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 /riscv Files generic to RISC-V architecture
147 /sandbox Files generic to HW-independent "sandbox"
148 /sh Files generic to SH architecture
149 /x86 Files generic to x86 architecture
150 /api Machine/arch independent API for external apps
151 /board Board dependent files
152 /cmd U-Boot commands functions
153 /common Misc architecture independent functions
154 /configs Board default configuration files
155 /disk Code for disk drive partition handling
156 /doc Documentation (don't expect too much)
157 /drivers Commonly used device drivers
158 /dts Contains Makefile for building internal U-Boot fdt.
159 /examples Example code for standalone applications, etc.
160 /fs Filesystem code (cramfs, ext2, jffs2, etc.)
161 /include Header Files
162 /lib Library routines generic to all architectures
163 /Licenses Various license files
165 /post Power On Self Test
166 /scripts Various build scripts and Makefiles
167 /test Various unit test files
168 /tools Tools to build S-Record or U-Boot images, etc.
170 Software Configuration:
171 =======================
173 Configuration is usually done using C preprocessor defines; the
174 rationale behind that is to avoid dead code whenever possible.
176 There are two classes of configuration variables:
178 * Configuration _OPTIONS_:
179 These are selectable by the user and have names beginning with
182 * Configuration _SETTINGS_:
183 These depend on the hardware etc. and should not be meddled with if
184 you don't know what you're doing; they have names beginning with
187 Previously, all configuration was done by hand, which involved creating
188 symbolic links and editing configuration files manually. More recently,
189 U-Boot has added the Kbuild infrastructure used by the Linux kernel,
190 allowing you to use the "make menuconfig" command to configure your
194 Selection of Processor Architecture and Board Type:
195 ---------------------------------------------------
197 For all supported boards there are ready-to-use default
198 configurations available; just type "make <board_name>_defconfig".
200 Example: For a TQM823L module type:
203 make TQM823L_defconfig
205 Note: If you're looking for the default configuration file for a board
206 you're sure used to be there but is now missing, check the file
207 doc/README.scrapyard for a list of no longer supported boards.
212 U-Boot can be built natively to run on a Linux host using the 'sandbox'
213 board. This allows feature development which is not board- or architecture-
214 specific to be undertaken on a native platform. The sandbox is also used to
215 run some of U-Boot's tests.
217 See board/sandbox/README.sandbox for more details.
220 Board Initialisation Flow:
221 --------------------------
223 This is the intended start-up flow for boards. This should apply for both
224 SPL and U-Boot proper (i.e. they both follow the same rules).
226 Note: "SPL" stands for "Secondary Program Loader," which is explained in
227 more detail later in this file.
229 At present, SPL mostly uses a separate code path, but the function names
230 and roles of each function are the same. Some boards or architectures
231 may not conform to this. At least most ARM boards which use
232 CONFIG_SPL_FRAMEWORK conform to this.
234 Execution typically starts with an architecture-specific (and possibly
235 CPU-specific) start.S file, such as:
237 - arch/arm/cpu/armv7/start.S
238 - arch/powerpc/cpu/mpc83xx/start.S
239 - arch/mips/cpu/start.S
241 and so on. From there, three functions are called; the purpose and
242 limitations of each of these functions are described below.
245 - purpose: essential init to permit execution to reach board_init_f()
246 - no global_data or BSS
247 - there is no stack (ARMv7 may have one but it will soon be removed)
248 - must not set up SDRAM or use console
249 - must only do the bare minimum to allow execution to continue to
251 - this is almost never needed
252 - return normally from this function
255 - purpose: set up the machine ready for running board_init_r():
256 i.e. SDRAM and serial UART
257 - global_data is available
259 - BSS is not available, so you cannot use global/static variables,
260 only stack variables and global_data
262 Non-SPL-specific notes:
263 - dram_init() is called to set up DRAM. If already done in SPL this
267 - you can override the entire board_init_f() function with your own
269 - preloader_console_init() can be called here in extremis
270 - should set up SDRAM, and anything needed to make the UART work
271 - these is no need to clear BSS, it will be done by crt0.S
272 - must return normally from this function (don't call board_init_r()
275 Here the BSS is cleared. For SPL, if CONFIG_SPL_STACK_R is defined, then at
276 this point the stack and global_data are relocated to below
277 CONFIG_SPL_STACK_R_ADDR. For non-SPL, U-Boot is relocated to run at the top of
281 - purpose: main execution, common code
282 - global_data is available
284 - BSS is available, all static/global variables can be used
285 - execution eventually continues to main_loop()
287 Non-SPL-specific notes:
288 - U-Boot is relocated to the top of memory and is now running from
292 - stack is optionally in SDRAM, if CONFIG_SPL_STACK_R is defined and
293 CONFIG_SPL_STACK_R_ADDR points into SDRAM
294 - preloader_console_init() can be called here - typically this is
295 done by selecting CONFIG_SPL_BOARD_INIT and then supplying a
296 spl_board_init() function containing this call
297 - loads U-Boot or (in falcon mode) Linux
301 Configuration Options:
302 ----------------------
304 Configuration depends on the combination of board and CPU type; all
305 such information is kept in a configuration file
306 "include/configs/<board_name>.h".
308 Example: For a TQM823L module, all configuration settings are in
309 "include/configs/TQM823L.h".
312 Many of the options are named exactly as the corresponding Linux
313 kernel configuration options. The intention is to make it easier to
314 build a config tool - later.
316 - ARM Platform Bus Type(CCI):
317 CoreLink Cache Coherent Interconnect (CCI) is ARM BUS which
318 provides full cache coherency between two clusters of multi-core
319 CPUs and I/O coherency for devices and I/O masters
321 CONFIG_SYS_FSL_HAS_CCI400
323 Defined For SoC that has cache coherent interconnect
326 CONFIG_SYS_FSL_HAS_CCN504
328 Defined for SoC that has cache coherent interconnect CCN-504
330 The following options need to be configured:
332 - CPU Type: Define exactly one, e.g. CONFIG_MPC85XX.
334 - Board Type: Define exactly one, e.g. CONFIG_MPC8540ADS.
336 - Marvell Family Member
337 CONFIG_SYS_MVFS - define it if you want to enable
338 multiple fs option at one time
339 for marvell soc family
344 Specifies that the core is a 64-bit PowerPC implementation (implements
345 the "64" category of the Power ISA). This is necessary for ePAPR
346 compliance, among other possible reasons.
348 CONFIG_SYS_FSL_TBCLK_DIV
350 Defines the core time base clock divider ratio compared to the
351 system clock. On most PQ3 devices this is 8, on newer QorIQ
352 devices it can be 16 or 32. The ratio varies from SoC to Soc.
354 CONFIG_SYS_FSL_PCIE_COMPAT
356 Defines the string to utilize when trying to match PCIe device
357 tree nodes for the given platform.
359 CONFIG_SYS_FSL_ERRATUM_A004510
361 Enables a workaround for erratum A004510. If set,
362 then CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV and
363 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY must be set.
365 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV
366 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV2 (optional)
368 Defines one or two SoC revisions (low 8 bits of SVR)
369 for which the A004510 workaround should be applied.
371 The rest of SVR is either not relevant to the decision
372 of whether the erratum is present (e.g. p2040 versus
373 p2041) or is implied by the build target, which controls
374 whether CONFIG_SYS_FSL_ERRATUM_A004510 is set.
376 See Freescale App Note 4493 for more information about
379 CONFIG_A003399_NOR_WORKAROUND
380 Enables a workaround for IFC erratum A003399. It is only
381 required during NOR boot.
383 CONFIG_A008044_WORKAROUND
384 Enables a workaround for T1040/T1042 erratum A008044. It is only
385 required during NAND boot and valid for Rev 1.0 SoC revision
387 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY
389 This is the value to write into CCSR offset 0x18600
390 according to the A004510 workaround.
392 CONFIG_SYS_FSL_DSP_DDR_ADDR
393 This value denotes start offset of DDR memory which is
394 connected exclusively to the DSP cores.
396 CONFIG_SYS_FSL_DSP_M2_RAM_ADDR
397 This value denotes start offset of M2 memory
398 which is directly connected to the DSP core.
400 CONFIG_SYS_FSL_DSP_M3_RAM_ADDR
401 This value denotes start offset of M3 memory which is directly
402 connected to the DSP core.
404 CONFIG_SYS_FSL_DSP_CCSRBAR_DEFAULT
405 This value denotes start offset of DSP CCSR space.
407 CONFIG_SYS_FSL_SINGLE_SOURCE_CLK
408 Single Source Clock is clocking mode present in some of FSL SoC's.
409 In this mode, a single differential clock is used to supply
410 clocks to the sysclock, ddrclock and usbclock.
412 CONFIG_SYS_CPC_REINIT_F
413 This CONFIG is defined when the CPC is configured as SRAM at the
414 time of U-Boot entry and is required to be re-initialized.
417 Indicates this SoC supports deep sleep feature. If deep sleep is
418 supported, core will start to execute uboot when wakes up.
420 - Generic CPU options:
421 CONFIG_SYS_BIG_ENDIAN, CONFIG_SYS_LITTLE_ENDIAN
423 Defines the endianess of the CPU. Implementation of those
424 values is arch specific.
427 Freescale DDR driver in use. This type of DDR controller is
428 found in mpc83xx, mpc85xx, mpc86xx as well as some ARM core
431 CONFIG_SYS_FSL_DDR_ADDR
432 Freescale DDR memory-mapped register base.
434 CONFIG_SYS_FSL_DDR_EMU
435 Specify emulator support for DDR. Some DDR features such as
436 deskew training are not available.
438 CONFIG_SYS_FSL_DDRC_GEN1
439 Freescale DDR1 controller.
441 CONFIG_SYS_FSL_DDRC_GEN2
442 Freescale DDR2 controller.
444 CONFIG_SYS_FSL_DDRC_GEN3
445 Freescale DDR3 controller.
447 CONFIG_SYS_FSL_DDRC_GEN4
448 Freescale DDR4 controller.
450 CONFIG_SYS_FSL_DDRC_ARM_GEN3
451 Freescale DDR3 controller for ARM-based SoCs.
454 Board config to use DDR1. It can be enabled for SoCs with
455 Freescale DDR1 or DDR2 controllers, depending on the board
459 Board config to use DDR2. It can be enabled for SoCs with
460 Freescale DDR2 or DDR3 controllers, depending on the board
464 Board config to use DDR3. It can be enabled for SoCs with
465 Freescale DDR3 or DDR3L controllers.
468 Board config to use DDR3L. It can be enabled for SoCs with
472 Board config to use DDR4. It can be enabled for SoCs with
475 CONFIG_SYS_FSL_IFC_BE
476 Defines the IFC controller register space as Big Endian
478 CONFIG_SYS_FSL_IFC_LE
479 Defines the IFC controller register space as Little Endian
481 CONFIG_SYS_FSL_IFC_CLK_DIV
482 Defines divider of platform clock(clock input to IFC controller).
484 CONFIG_SYS_FSL_LBC_CLK_DIV
485 Defines divider of platform clock(clock input to eLBC controller).
487 CONFIG_SYS_FSL_PBL_PBI
488 It enables addition of RCW (Power on reset configuration) in built image.
489 Please refer doc/README.pblimage for more details
491 CONFIG_SYS_FSL_PBL_RCW
492 It adds PBI(pre-boot instructions) commands in u-boot build image.
493 PBI commands can be used to configure SoC before it starts the execution.
494 Please refer doc/README.pblimage for more details
497 It adds a target to create boot binary having SPL binary in PBI format
498 concatenated with u-boot binary.
500 CONFIG_SYS_FSL_DDR_BE
501 Defines the DDR controller register space as Big Endian
503 CONFIG_SYS_FSL_DDR_LE
504 Defines the DDR controller register space as Little Endian
506 CONFIG_SYS_FSL_DDR_SDRAM_BASE_PHY
507 Physical address from the view of DDR controllers. It is the
508 same as CONFIG_SYS_DDR_SDRAM_BASE for all Power SoCs. But
509 it could be different for ARM SoCs.
511 CONFIG_SYS_FSL_DDR_INTLV_256B
512 DDR controller interleaving on 256-byte. This is a special
513 interleaving mode, handled by Dickens for Freescale layerscape
516 CONFIG_SYS_FSL_DDR_MAIN_NUM_CTRLS
517 Number of controllers used as main memory.
519 CONFIG_SYS_FSL_OTHER_DDR_NUM_CTRLS
520 Number of controllers used for other than main memory.
522 CONFIG_SYS_FSL_HAS_DP_DDR
523 Defines the SoC has DP-DDR used for DPAA.
525 CONFIG_SYS_FSL_SEC_BE
526 Defines the SEC controller register space as Big Endian
528 CONFIG_SYS_FSL_SEC_LE
529 Defines the SEC controller register space as Little Endian
532 CONFIG_SYS_INIT_SP_OFFSET
534 Offset relative to CONFIG_SYS_SDRAM_BASE for initial stack
535 pointer. This is needed for the temporary stack before
538 CONFIG_SYS_MIPS_CACHE_MODE
540 Cache operation mode for the MIPS CPU.
541 See also arch/mips/include/asm/mipsregs.h.
543 CONF_CM_CACHABLE_NO_WA
546 CONF_CM_CACHABLE_NONCOHERENT
550 CONF_CM_CACHABLE_ACCELERATED
552 CONFIG_SYS_XWAY_EBU_BOOTCFG
554 Special option for Lantiq XWAY SoCs for booting from NOR flash.
555 See also arch/mips/cpu/mips32/start.S.
557 CONFIG_XWAY_SWAP_BYTES
559 Enable compilation of tools/xway-swap-bytes needed for Lantiq
560 XWAY SoCs for booting from NOR flash. The U-Boot image needs to
561 be swapped if a flash programmer is used.
564 CONFIG_SYS_EXCEPTION_VECTORS_HIGH
566 Select high exception vectors of the ARM core, e.g., do not
567 clear the V bit of the c1 register of CP15.
570 Generic timer clock source frequency.
572 COUNTER_FREQUENCY_REAL
573 Generic timer clock source frequency if the real clock is
574 different from COUNTER_FREQUENCY, and can only be determined
578 CONFIG_TEGRA_SUPPORT_NON_SECURE
580 Support executing U-Boot in non-secure (NS) mode. Certain
581 impossible actions will be skipped if the CPU is in NS mode,
582 such as ARM architectural timer initialization.
584 - Linux Kernel Interface:
587 U-Boot stores all clock information in Hz
588 internally. For binary compatibility with older Linux
589 kernels (which expect the clocks passed in the
590 bd_info data to be in MHz) the environment variable
591 "clocks_in_mhz" can be defined so that U-Boot
592 converts clock data to MHZ before passing it to the
594 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
595 "clocks_in_mhz=1" is automatically included in the
598 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
600 When transferring memsize parameter to Linux, some versions
601 expect it to be in bytes, others in MB.
602 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
606 New kernel versions are expecting firmware settings to be
607 passed using flattened device trees (based on open firmware
611 * New libfdt-based support
612 * Adds the "fdt" command
613 * The bootm command automatically updates the fdt
615 OF_TBCLK - The timebase frequency.
616 OF_STDOUT_PATH - The path to the console device
618 boards with QUICC Engines require OF_QE to set UCC MAC
621 CONFIG_OF_BOARD_SETUP
623 Board code has addition modification that it wants to make
624 to the flat device tree before handing it off to the kernel
626 CONFIG_OF_SYSTEM_SETUP
628 Other code has addition modification that it wants to make
629 to the flat device tree before handing it off to the kernel.
630 This causes ft_system_setup() to be called before booting
635 U-Boot can detect if an IDE device is present or not.
636 If not, and this new config option is activated, U-Boot
637 removes the ATA node from the DTS before booting Linux,
638 so the Linux IDE driver does not probe the device and
639 crash. This is needed for buggy hardware (uc101) where
640 no pull down resistor is connected to the signal IDE5V_DD7.
642 CONFIG_MACH_TYPE [relevant for ARM only][mandatory]
644 This setting is mandatory for all boards that have only one
645 machine type and must be used to specify the machine type
646 number as it appears in the ARM machine registry
647 (see http://www.arm.linux.org.uk/developer/machines/).
648 Only boards that have multiple machine types supported
649 in a single configuration file and the machine type is
650 runtime discoverable, do not have to use this setting.
652 - vxWorks boot parameters:
654 bootvx constructs a valid bootline using the following
655 environments variables: bootdev, bootfile, ipaddr, netmask,
656 serverip, gatewayip, hostname, othbootargs.
657 It loads the vxWorks image pointed bootfile.
659 Note: If a "bootargs" environment is defined, it will overwride
660 the defaults discussed just above.
662 - Cache Configuration:
663 CONFIG_SYS_ICACHE_OFF - Do not enable instruction cache in U-Boot
664 CONFIG_SYS_DCACHE_OFF - Do not enable data cache in U-Boot
665 CONFIG_SYS_L2CACHE_OFF- Do not enable L2 cache in U-Boot
667 - Cache Configuration for ARM:
668 CONFIG_SYS_L2_PL310 - Enable support for ARM PL310 L2 cache
670 CONFIG_SYS_PL310_BASE - Physical base address of PL310
671 controller register space
676 Define this if you want support for Amba PrimeCell PL010 UARTs.
680 Define this if you want support for Amba PrimeCell PL011 UARTs.
684 If you have Amba PrimeCell PL011 UARTs, set this variable to
685 the clock speed of the UARTs.
689 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
690 define this to a list of base addresses for each (supported)
691 port. See e.g. include/configs/versatile.h
693 CONFIG_SERIAL_HW_FLOW_CONTROL
695 Define this variable to enable hw flow control in serial driver.
696 Current user of this option is drivers/serial/nsl16550.c driver
699 CONFIG_BAUDRATE - in bps
700 Select one of the baudrates listed in
701 CONFIG_SYS_BAUDRATE_TABLE, see below.
705 Only needed when CONFIG_BOOTDELAY is enabled;
706 define a command string that is automatically executed
707 when no character is read on the console interface
708 within "Boot Delay" after reset.
710 CONFIG_RAMBOOT and CONFIG_NFSBOOT
711 The value of these goes into the environment as
712 "ramboot" and "nfsboot" respectively, and can be used
713 as a convenience, when switching between booting from
718 If no softreset save registers are found on the hardware
719 "bootcount" is stored in the environment. To prevent a
720 saveenv on all reboots, the environment variable
721 "upgrade_available" is used. If "upgrade_available" is
722 0, "bootcount" is always 0, if "upgrade_available" is
723 1 "bootcount" is incremented in the environment.
724 So the Userspace Applikation must set the "upgrade_available"
725 and "bootcount" variable to 0, if a boot was successfully.
730 When this option is #defined, the existence of the
731 environment variable "preboot" will be checked
732 immediately before starting the CONFIG_BOOTDELAY
733 countdown and/or running the auto-boot command resp.
734 entering interactive mode.
736 This feature is especially useful when "preboot" is
737 automatically generated or modified. For an example
738 see the LWMON board specific code: here "preboot" is
739 modified when the user holds down a certain
740 combination of keys on the (special) keyboard when
743 - Serial Download Echo Mode:
745 If defined to 1, all characters received during a
746 serial download (using the "loads" command) are
747 echoed back. This might be needed by some terminal
748 emulations (like "cu"), but may as well just take
749 time on others. This setting #define's the initial
750 value of the "loads_echo" environment variable.
752 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
754 Select one of the baudrates listed in
755 CONFIG_SYS_BAUDRATE_TABLE, see below.
757 - Removal of commands
758 If no commands are needed to boot, you can disable
759 CONFIG_CMDLINE to remove them. In this case, the command line
760 will not be available, and when U-Boot wants to execute the
761 boot command (on start-up) it will call board_run_command()
762 instead. This can reduce image size significantly for very
763 simple boot procedures.
765 - Regular expression support:
767 If this variable is defined, U-Boot is linked against
768 the SLRE (Super Light Regular Expression) library,
769 which adds regex support to some commands, as for
770 example "env grep" and "setexpr".
774 If this variable is defined, U-Boot will use a device tree
775 to configure its devices, instead of relying on statically
776 compiled #defines in the board file. This option is
777 experimental and only available on a few boards. The device
778 tree is available in the global data as gd->fdt_blob.
780 U-Boot needs to get its device tree from somewhere. This can
781 be done using one of the three options below:
784 If this variable is defined, U-Boot will embed a device tree
785 binary in its image. This device tree file should be in the
786 board directory and called <soc>-<board>.dts. The binary file
787 is then picked up in board_init_f() and made available through
788 the global data structure as gd->fdt_blob.
791 If this variable is defined, U-Boot will build a device tree
792 binary. It will be called u-boot.dtb. Architecture-specific
793 code will locate it at run-time. Generally this works by:
795 cat u-boot.bin u-boot.dtb >image.bin
797 and in fact, U-Boot does this for you, creating a file called
798 u-boot-dtb.bin which is useful in the common case. You can
799 still use the individual files if you need something more
803 If this variable is defined, U-Boot will use the device tree
804 provided by the board at runtime instead of embedding one with
805 the image. Only boards defining board_fdt_blob_setup() support
806 this option (see include/fdtdec.h file).
810 If this variable is defined, it enables watchdog
811 support for the SoC. There must be support in the SoC
812 specific code for a watchdog. For the 8xx
813 CPUs, the SIU Watchdog feature is enabled in the SYPCR
814 register. When supported for a specific SoC is
815 available, then no further board specific code should
819 When using a watchdog circuitry external to the used
820 SoC, then define this variable and provide board
821 specific code for the "hw_watchdog_reset" function.
823 CONFIG_AT91_HW_WDT_TIMEOUT
824 specify the timeout in seconds. default 2 seconds.
827 CONFIG_VERSION_VARIABLE
828 If this variable is defined, an environment variable
829 named "ver" is created by U-Boot showing the U-Boot
830 version as printed by the "version" command.
831 Any change to this variable will be reverted at the
836 When CONFIG_CMD_DATE is selected, the type of the RTC
837 has to be selected, too. Define exactly one of the
840 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
841 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC
842 CONFIG_RTC_MC146818 - use MC146818 RTC
843 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
844 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
845 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
846 CONFIG_RTC_DS1339 - use Maxim, Inc. DS1339 RTC
847 CONFIG_RTC_DS164x - use Dallas DS164x RTC
848 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
849 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
850 CONFIG_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
851 CONFIG_SYS_RV3029_TCR - enable trickle charger on
854 Note that if the RTC uses I2C, then the I2C interface
855 must also be configured. See I2C Support, below.
858 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
860 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
861 chip-ngpio pairs that tell the PCA953X driver the number of
862 pins supported by a particular chip.
864 Note that if the GPIO device uses I2C, then the I2C interface
865 must also be configured. See I2C Support, below.
868 When CONFIG_IO_TRACE is selected, U-Boot intercepts all I/O
869 accesses and can checksum them or write a list of them out
870 to memory. See the 'iotrace' command for details. This is
871 useful for testing device drivers since it can confirm that
872 the driver behaves the same way before and after a code
873 change. Currently this is supported on sandbox and arm. To
874 add support for your architecture, add '#include <iotrace.h>'
875 to the bottom of arch/<arch>/include/asm/io.h and test.
877 Example output from the 'iotrace stats' command is below.
878 Note that if the trace buffer is exhausted, the checksum will
879 still continue to operate.
882 Start: 10000000 (buffer start address)
883 Size: 00010000 (buffer size)
884 Offset: 00000120 (current buffer offset)
885 Output: 10000120 (start + offset)
886 Count: 00000018 (number of trace records)
887 CRC32: 9526fb66 (CRC32 of all trace records)
891 When CONFIG_TIMESTAMP is selected, the timestamp
892 (date and time) of an image is printed by image
893 commands like bootm or iminfo. This option is
894 automatically enabled when you select CONFIG_CMD_DATE .
896 - Partition Labels (disklabels) Supported:
897 Zero or more of the following:
898 CONFIG_MAC_PARTITION Apple's MacOS partition table.
899 CONFIG_ISO_PARTITION ISO partition table, used on CDROM etc.
900 CONFIG_EFI_PARTITION GPT partition table, common when EFI is the
901 bootloader. Note 2TB partition limit; see
903 CONFIG_MTD_PARTITIONS Memory Technology Device partition table.
905 If IDE or SCSI support is enabled (CONFIG_IDE or
906 CONFIG_SCSI) you must configure support for at
907 least one non-MTD partition type as well.
910 CONFIG_IDE_RESET_ROUTINE - this is defined in several
911 board configurations files but used nowhere!
913 CONFIG_IDE_RESET - is this is defined, IDE Reset will
914 be performed by calling the function
915 ide_set_reset(int reset)
916 which has to be defined in a board specific file
921 Set this to enable ATAPI support.
926 Set this to enable support for disks larger than 137GB
927 Also look at CONFIG_SYS_64BIT_LBA.
928 Whithout these , LBA48 support uses 32bit variables and will 'only'
929 support disks up to 2.1TB.
931 CONFIG_SYS_64BIT_LBA:
932 When enabled, makes the IDE subsystem use 64bit sector addresses.
936 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
937 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
938 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
939 maximum numbers of LUNs, SCSI ID's and target
942 The environment variable 'scsidevs' is set to the number of
943 SCSI devices found during the last scan.
945 - NETWORK Support (PCI):
947 Support for Intel 8254x/8257x gigabit chips.
950 Utility code for direct access to the SPI bus on Intel 8257x.
951 This does not do anything useful unless you set at least one
952 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
954 CONFIG_E1000_SPI_GENERIC
955 Allow generic access to the SPI bus on the Intel 8257x, for
956 example with the "sspi" command.
959 Support for Intel 82557/82559/82559ER chips.
960 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
961 write routine for first time initialisation.
964 Support for Digital 2114x chips.
965 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
966 modem chip initialisation (KS8761/QS6611).
969 Support for National dp83815 chips.
972 Support for National dp8382[01] gigabit chips.
974 - NETWORK Support (other):
976 CONFIG_DRIVER_AT91EMAC
977 Support for AT91RM9200 EMAC.
980 Define this to use reduced MII inteface
982 CONFIG_DRIVER_AT91EMAC_QUIET
983 If this defined, the driver is quiet.
984 The driver doen't show link status messages.
987 Support for the Calxeda XGMAC device
990 Support for SMSC's LAN91C96 chips.
992 CONFIG_LAN91C96_USE_32_BIT
993 Define this to enable 32 bit addressing
996 Support for SMSC's LAN91C111 chip
999 Define this to hold the physical address
1000 of the device (I/O space)
1002 CONFIG_SMC_USE_32_BIT
1003 Define this if data bus is 32 bits
1005 CONFIG_SMC_USE_IOFUNCS
1006 Define this to use i/o functions instead of macros
1007 (some hardware wont work with macros)
1009 CONFIG_DRIVER_TI_EMAC
1010 Support for davinci emac
1012 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
1013 Define this if you have more then 3 PHYs.
1016 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
1018 CONFIG_FTGMAC100_EGIGA
1019 Define this to use GE link update with gigabit PHY.
1020 Define this if FTGMAC100 is connected to gigabit PHY.
1021 If your system has 10/100 PHY only, it might not occur
1022 wrong behavior. Because PHY usually return timeout or
1023 useless data when polling gigabit status and gigabit
1024 control registers. This behavior won't affect the
1025 correctnessof 10/100 link speed update.
1028 Support for Renesas on-chip Ethernet controller
1030 CONFIG_SH_ETHER_USE_PORT
1031 Define the number of ports to be used
1033 CONFIG_SH_ETHER_PHY_ADDR
1034 Define the ETH PHY's address
1036 CONFIG_SH_ETHER_CACHE_WRITEBACK
1037 If this option is set, the driver enables cache flush.
1041 Support for PWM module on the imx6.
1045 Support TPM devices.
1047 CONFIG_TPM_TIS_INFINEON
1048 Support for Infineon i2c bus TPM devices. Only one device
1049 per system is supported at this time.
1051 CONFIG_TPM_TIS_I2C_BURST_LIMITATION
1052 Define the burst count bytes upper limit
1055 Support for STMicroelectronics TPM devices. Requires DM_TPM support.
1057 CONFIG_TPM_ST33ZP24_I2C
1058 Support for STMicroelectronics ST33ZP24 I2C devices.
1059 Requires TPM_ST33ZP24 and I2C.
1061 CONFIG_TPM_ST33ZP24_SPI
1062 Support for STMicroelectronics ST33ZP24 SPI devices.
1063 Requires TPM_ST33ZP24 and SPI.
1065 CONFIG_TPM_ATMEL_TWI
1066 Support for Atmel TWI TPM device. Requires I2C support.
1069 Support for generic parallel port TPM devices. Only one device
1070 per system is supported at this time.
1072 CONFIG_TPM_TIS_BASE_ADDRESS
1073 Base address where the generic TPM device is mapped
1074 to. Contemporary x86 systems usually map it at
1078 Define this to enable the TPM support library which provides
1079 functional interfaces to some TPM commands.
1080 Requires support for a TPM device.
1082 CONFIG_TPM_AUTH_SESSIONS
1083 Define this to enable authorized functions in the TPM library.
1084 Requires CONFIG_TPM and CONFIG_SHA1.
1087 At the moment only the UHCI host controller is
1088 supported (PIP405, MIP405); define
1089 CONFIG_USB_UHCI to enable it.
1090 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
1091 and define CONFIG_USB_STORAGE to enable the USB
1094 Supported are USB Keyboards and USB Floppy drives
1097 CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
1098 txfilltuning field in the EHCI controller on reset.
1100 CONFIG_USB_DWC2_REG_ADDR the physical CPU address of the DWC2
1101 HW module registers.
1104 Define the below if you wish to use the USB console.
1105 Once firmware is rebuilt from a serial console issue the
1106 command "setenv stdin usbtty; setenv stdout usbtty" and
1107 attach your USB cable. The Unix command "dmesg" should print
1108 it has found a new device. The environment variable usbtty
1109 can be set to gserial or cdc_acm to enable your device to
1110 appear to a USB host as a Linux gserial device or a
1111 Common Device Class Abstract Control Model serial device.
1112 If you select usbtty = gserial you should be able to enumerate
1114 # modprobe usbserial vendor=0xVendorID product=0xProductID
1115 else if using cdc_acm, simply setting the environment
1116 variable usbtty to be cdc_acm should suffice. The following
1117 might be defined in YourBoardName.h
1120 Define this to build a UDC device
1123 Define this to have a tty type of device available to
1124 talk to the UDC device
1127 Define this to enable the high speed support for usb
1128 device and usbtty. If this feature is enabled, a routine
1129 int is_usbd_high_speed(void)
1130 also needs to be defined by the driver to dynamically poll
1131 whether the enumeration has succeded at high speed or full
1134 CONFIG_SYS_CONSOLE_IS_IN_ENV
1135 Define this if you want stdin, stdout &/or stderr to
1138 If you have a USB-IF assigned VendorID then you may wish to
1139 define your own vendor specific values either in BoardName.h
1140 or directly in usbd_vendor_info.h. If you don't define
1141 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
1142 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
1143 should pretend to be a Linux device to it's target host.
1145 CONFIG_USBD_MANUFACTURER
1146 Define this string as the name of your company for
1147 - CONFIG_USBD_MANUFACTURER "my company"
1149 CONFIG_USBD_PRODUCT_NAME
1150 Define this string as the name of your product
1151 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
1153 CONFIG_USBD_VENDORID
1154 Define this as your assigned Vendor ID from the USB
1155 Implementors Forum. This *must* be a genuine Vendor ID
1156 to avoid polluting the USB namespace.
1157 - CONFIG_USBD_VENDORID 0xFFFF
1159 CONFIG_USBD_PRODUCTID
1160 Define this as the unique Product ID
1162 - CONFIG_USBD_PRODUCTID 0xFFFF
1164 - ULPI Layer Support:
1165 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
1166 the generic ULPI layer. The generic layer accesses the ULPI PHY
1167 via the platform viewport, so you need both the genric layer and
1168 the viewport enabled. Currently only Chipidea/ARC based
1169 viewport is supported.
1170 To enable the ULPI layer support, define CONFIG_USB_ULPI and
1171 CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
1172 If your ULPI phy needs a different reference clock than the
1173 standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to
1174 the appropriate value in Hz.
1177 The MMC controller on the Intel PXA is supported. To
1178 enable this define CONFIG_MMC. The MMC can be
1179 accessed from the boot prompt by mapping the device
1180 to physical memory similar to flash. Command line is
1181 enabled with CONFIG_CMD_MMC. The MMC driver also works with
1182 the FAT fs. This is enabled with CONFIG_CMD_FAT.
1185 Support for Renesas on-chip MMCIF controller
1187 CONFIG_SH_MMCIF_ADDR
1188 Define the base address of MMCIF registers
1191 Define the clock frequency for MMCIF
1193 CONFIG_SUPPORT_EMMC_BOOT
1194 Enable some additional features of the eMMC boot partitions.
1196 CONFIG_SUPPORT_EMMC_RPMB
1197 Enable the commands for reading, writing and programming the
1198 key for the Replay Protection Memory Block partition in eMMC.
1200 - USB Device Firmware Update (DFU) class support:
1202 This enables the USB portion of the DFU USB class
1205 This enables support for exposing (e)MMC devices via DFU.
1208 This enables support for exposing NAND devices via DFU.
1211 This enables support for exposing RAM via DFU.
1212 Note: DFU spec refer to non-volatile memory usage, but
1213 allow usages beyond the scope of spec - here RAM usage,
1214 one that would help mostly the developer.
1216 CONFIG_SYS_DFU_DATA_BUF_SIZE
1217 Dfu transfer uses a buffer before writing data to the
1218 raw storage device. Make the size (in bytes) of this buffer
1219 configurable. The size of this buffer is also configurable
1220 through the "dfu_bufsiz" environment variable.
1222 CONFIG_SYS_DFU_MAX_FILE_SIZE
1223 When updating files rather than the raw storage device,
1224 we use a static buffer to copy the file into and then write
1225 the buffer once we've been given the whole file. Define
1226 this to the maximum filesize (in bytes) for the buffer.
1227 Default is 4 MiB if undefined.
1229 DFU_DEFAULT_POLL_TIMEOUT
1230 Poll timeout [ms], is the timeout a device can send to the
1231 host. The host must wait for this timeout before sending
1232 a subsequent DFU_GET_STATUS request to the device.
1234 DFU_MANIFEST_POLL_TIMEOUT
1235 Poll timeout [ms], which the device sends to the host when
1236 entering dfuMANIFEST state. Host waits this timeout, before
1237 sending again an USB request to the device.
1239 - Journaling Flash filesystem support:
1241 Define these for a default partition on a NAND device
1243 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1244 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1245 Define these for a default partition on a NOR device
1248 See Kconfig help for available keyboard drivers.
1252 Define this to enable a custom keyboard support.
1253 This simply calls drv_keyboard_init() which must be
1254 defined in your board-specific files. This option is deprecated
1255 and is only used by novena. For new boards, use driver model
1260 Enable the Freescale DIU video driver. Reference boards for
1261 SOCs that have a DIU should define this macro to enable DIU
1262 support, and should also define these other macros:
1267 CONFIG_VIDEO_SW_CURSOR
1268 CONFIG_VGA_AS_SINGLE_DEVICE
1270 CONFIG_VIDEO_BMP_LOGO
1272 The DIU driver will look for the 'video-mode' environment
1273 variable, and if defined, enable the DIU as a console during
1274 boot. See the documentation file doc/README.video for a
1275 description of this variable.
1277 - LCD Support: CONFIG_LCD
1279 Define this to enable LCD support (for output to LCD
1280 display); also select one of the supported displays
1281 by defining one of these:
1285 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1287 CONFIG_NEC_NL6448AC33:
1289 NEC NL6448AC33-18. Active, color, single scan.
1291 CONFIG_NEC_NL6448BC20
1293 NEC NL6448BC20-08. 6.5", 640x480.
1294 Active, color, single scan.
1296 CONFIG_NEC_NL6448BC33_54
1298 NEC NL6448BC33-54. 10.4", 640x480.
1299 Active, color, single scan.
1303 Sharp 320x240. Active, color, single scan.
1304 It isn't 16x9, and I am not sure what it is.
1306 CONFIG_SHARP_LQ64D341
1308 Sharp LQ64D341 display, 640x480.
1309 Active, color, single scan.
1313 HLD1045 display, 640x480.
1314 Active, color, single scan.
1318 Optrex CBL50840-2 NF-FW 99 22 M5
1320 Hitachi LMG6912RPFC-00T
1324 320x240. Black & white.
1326 CONFIG_LCD_ALIGNMENT
1328 Normally the LCD is page-aligned (typically 4KB). If this is
1329 defined then the LCD will be aligned to this value instead.
1330 For ARM it is sometimes useful to use MMU_SECTION_SIZE
1331 here, since it is cheaper to change data cache settings on
1332 a per-section basis.
1337 Sometimes, for example if the display is mounted in portrait
1338 mode or even if it's mounted landscape but rotated by 180degree,
1339 we need to rotate our content of the display relative to the
1340 framebuffer, so that user can read the messages which are
1342 Once CONFIG_LCD_ROTATION is defined, the lcd_console will be
1343 initialized with a given rotation from "vl_rot" out of
1344 "vidinfo_t" which is provided by the board specific code.
1345 The value for vl_rot is coded as following (matching to
1346 fbcon=rotate:<n> linux-kernel commandline):
1347 0 = no rotation respectively 0 degree
1348 1 = 90 degree rotation
1349 2 = 180 degree rotation
1350 3 = 270 degree rotation
1352 If CONFIG_LCD_ROTATION is not defined, the console will be
1353 initialized with 0degree rotation.
1357 Support drawing of RLE8-compressed bitmaps on the LCD.
1361 Enables an 'i2c edid' command which can read EDID
1362 information over I2C from an attached LCD display.
1364 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1366 If this option is set, the environment is checked for
1367 a variable "splashimage". If found, the usual display
1368 of logo, copyright and system information on the LCD
1369 is suppressed and the BMP image at the address
1370 specified in "splashimage" is loaded instead. The
1371 console is redirected to the "nulldev", too. This
1372 allows for a "silent" boot where a splash screen is
1373 loaded very quickly after power-on.
1375 CONFIG_SPLASHIMAGE_GUARD
1377 If this option is set, then U-Boot will prevent the environment
1378 variable "splashimage" from being set to a problematic address
1379 (see doc/README.displaying-bmps).
1380 This option is useful for targets where, due to alignment
1381 restrictions, an improperly aligned BMP image will cause a data
1382 abort. If you think you will not have problems with unaligned
1383 accesses (for example because your toolchain prevents them)
1384 there is no need to set this option.
1386 CONFIG_SPLASH_SCREEN_ALIGN
1388 If this option is set the splash image can be freely positioned
1389 on the screen. Environment variable "splashpos" specifies the
1390 position as "x,y". If a positive number is given it is used as
1391 number of pixel from left/top. If a negative number is given it
1392 is used as number of pixel from right/bottom. You can also
1393 specify 'm' for centering the image.
1396 setenv splashpos m,m
1397 => image at center of screen
1399 setenv splashpos 30,20
1400 => image at x = 30 and y = 20
1402 setenv splashpos -10,m
1403 => vertically centered image
1404 at x = dspWidth - bmpWidth - 9
1406 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1408 If this option is set, additionally to standard BMP
1409 images, gzipped BMP images can be displayed via the
1410 splashscreen support or the bmp command.
1412 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1414 If this option is set, 8-bit RLE compressed BMP images
1415 can be displayed via the splashscreen support or the
1418 - Compression support:
1421 Enabled by default to support gzip compressed images.
1425 If this option is set, support for bzip2 compressed
1426 images is included. If not, only uncompressed and gzip
1427 compressed images are supported.
1429 NOTE: the bzip2 algorithm requires a lot of RAM, so
1430 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1436 The address of PHY on MII bus.
1438 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1440 The clock frequency of the MII bus
1442 CONFIG_PHY_RESET_DELAY
1444 Some PHY like Intel LXT971A need extra delay after
1445 reset before any MII register access is possible.
1446 For such PHY, set this option to the usec delay
1447 required. (minimum 300usec for LXT971A)
1449 CONFIG_PHY_CMD_DELAY (ppc4xx)
1451 Some PHY like Intel LXT971A need extra delay after
1452 command issued before MII status register can be read
1457 Define a default value for the IP address to use for
1458 the default Ethernet interface, in case this is not
1459 determined through e.g. bootp.
1460 (Environment variable "ipaddr")
1462 - Server IP address:
1465 Defines a default value for the IP address of a TFTP
1466 server to contact when using the "tftboot" command.
1467 (Environment variable "serverip")
1469 CONFIG_KEEP_SERVERADDR
1471 Keeps the server's MAC address, in the env 'serveraddr'
1472 for passing to bootargs (like Linux's netconsole option)
1474 - Gateway IP address:
1477 Defines a default value for the IP address of the
1478 default router where packets to other networks are
1480 (Environment variable "gatewayip")
1485 Defines a default value for the subnet mask (or
1486 routing prefix) which is used to determine if an IP
1487 address belongs to the local subnet or needs to be
1488 forwarded through a router.
1489 (Environment variable "netmask")
1491 - Multicast TFTP Mode:
1494 Defines whether you want to support multicast TFTP as per
1495 rfc-2090; for example to work with atftp. Lets lots of targets
1496 tftp down the same boot image concurrently. Note: the Ethernet
1497 driver in use must provide a function: mcast() to join/leave a
1500 - BOOTP Recovery Mode:
1501 CONFIG_BOOTP_RANDOM_DELAY
1503 If you have many targets in a network that try to
1504 boot using BOOTP, you may want to avoid that all
1505 systems send out BOOTP requests at precisely the same
1506 moment (which would happen for instance at recovery
1507 from a power failure, when all systems will try to
1508 boot, thus flooding the BOOTP server. Defining
1509 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1510 inserted before sending out BOOTP requests. The
1511 following delays are inserted then:
1513 1st BOOTP request: delay 0 ... 1 sec
1514 2nd BOOTP request: delay 0 ... 2 sec
1515 3rd BOOTP request: delay 0 ... 4 sec
1517 BOOTP requests: delay 0 ... 8 sec
1519 CONFIG_BOOTP_ID_CACHE_SIZE
1521 BOOTP packets are uniquely identified using a 32-bit ID. The
1522 server will copy the ID from client requests to responses and
1523 U-Boot will use this to determine if it is the destination of
1524 an incoming response. Some servers will check that addresses
1525 aren't in use before handing them out (usually using an ARP
1526 ping) and therefore take up to a few hundred milliseconds to
1527 respond. Network congestion may also influence the time it
1528 takes for a response to make it back to the client. If that
1529 time is too long, U-Boot will retransmit requests. In order
1530 to allow earlier responses to still be accepted after these
1531 retransmissions, U-Boot's BOOTP client keeps a small cache of
1532 IDs. The CONFIG_BOOTP_ID_CACHE_SIZE controls the size of this
1533 cache. The default is to keep IDs for up to four outstanding
1534 requests. Increasing this will allow U-Boot to accept offers
1535 from a BOOTP client in networks with unusually high latency.
1537 - DHCP Advanced Options:
1538 You can fine tune the DHCP functionality by defining
1539 CONFIG_BOOTP_* symbols:
1541 CONFIG_BOOTP_NISDOMAIN
1542 CONFIG_BOOTP_BOOTFILESIZE
1543 CONFIG_BOOTP_SEND_HOSTNAME
1544 CONFIG_BOOTP_NTPSERVER
1545 CONFIG_BOOTP_TIMEOFFSET
1546 CONFIG_BOOTP_VENDOREX
1547 CONFIG_BOOTP_MAY_FAIL
1549 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1550 environment variable, not the BOOTP server.
1552 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
1553 after the configured retry count, the call will fail
1554 instead of starting over. This can be used to fail over
1555 to Link-local IP address configuration if the DHCP server
1558 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1559 to do a dynamic update of a DNS server. To do this, they
1560 need the hostname of the DHCP requester.
1561 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1562 of the "hostname" environment variable is passed as
1563 option 12 to the DHCP server.
1565 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1567 A 32bit value in microseconds for a delay between
1568 receiving a "DHCP Offer" and sending the "DHCP Request".
1569 This fixes a problem with certain DHCP servers that don't
1570 respond 100% of the time to a "DHCP request". E.g. On an
1571 AT91RM9200 processor running at 180MHz, this delay needed
1572 to be *at least* 15,000 usec before a Windows Server 2003
1573 DHCP server would reply 100% of the time. I recommend at
1574 least 50,000 usec to be safe. The alternative is to hope
1575 that one of the retries will be successful but note that
1576 the DHCP timeout and retry process takes a longer than
1579 - Link-local IP address negotiation:
1580 Negotiate with other link-local clients on the local network
1581 for an address that doesn't require explicit configuration.
1582 This is especially useful if a DHCP server cannot be guaranteed
1583 to exist in all environments that the device must operate.
1585 See doc/README.link-local for more information.
1587 - MAC address from environment variables
1589 FDT_SEQ_MACADDR_FROM_ENV
1591 Fix-up device tree with MAC addresses fetched sequentially from
1592 environment variables. This config work on assumption that
1593 non-usable ethernet node of device-tree are either not present
1594 or their status has been marked as "disabled".
1597 CONFIG_CDP_DEVICE_ID
1599 The device id used in CDP trigger frames.
1601 CONFIG_CDP_DEVICE_ID_PREFIX
1603 A two character string which is prefixed to the MAC address
1608 A printf format string which contains the ascii name of
1609 the port. Normally is set to "eth%d" which sets
1610 eth0 for the first Ethernet, eth1 for the second etc.
1612 CONFIG_CDP_CAPABILITIES
1614 A 32bit integer which indicates the device capabilities;
1615 0x00000010 for a normal host which does not forwards.
1619 An ascii string containing the version of the software.
1623 An ascii string containing the name of the platform.
1627 A 32bit integer sent on the trigger.
1629 CONFIG_CDP_POWER_CONSUMPTION
1631 A 16bit integer containing the power consumption of the
1632 device in .1 of milliwatts.
1634 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1636 A byte containing the id of the VLAN.
1638 - Status LED: CONFIG_LED_STATUS
1640 Several configurations allow to display the current
1641 status using a LED. For instance, the LED will blink
1642 fast while running U-Boot code, stop blinking as
1643 soon as a reply to a BOOTP request was received, and
1644 start blinking slow once the Linux kernel is running
1645 (supported by a status LED driver in the Linux
1646 kernel). Defining CONFIG_LED_STATUS enables this
1651 CONFIG_LED_STATUS_GPIO
1652 The status LED can be connected to a GPIO pin.
1653 In such cases, the gpio_led driver can be used as a
1654 status LED backend implementation. Define CONFIG_LED_STATUS_GPIO
1655 to include the gpio_led driver in the U-Boot binary.
1657 CONFIG_GPIO_LED_INVERTED_TABLE
1658 Some GPIO connected LEDs may have inverted polarity in which
1659 case the GPIO high value corresponds to LED off state and
1660 GPIO low value corresponds to LED on state.
1661 In such cases CONFIG_GPIO_LED_INVERTED_TABLE may be defined
1662 with a list of GPIO LEDs that have inverted polarity.
1664 - I2C Support: CONFIG_SYS_I2C
1666 This enable the NEW i2c subsystem, and will allow you to use
1667 i2c commands at the u-boot command line (as long as you set
1668 CONFIG_CMD_I2C in CONFIG_COMMANDS) and communicate with i2c
1669 based realtime clock chips or other i2c devices. See
1670 common/cmd_i2c.c for a description of the command line
1673 ported i2c driver to the new framework:
1674 - drivers/i2c/soft_i2c.c:
1675 - activate first bus with CONFIG_SYS_I2C_SOFT define
1676 CONFIG_SYS_I2C_SOFT_SPEED and CONFIG_SYS_I2C_SOFT_SLAVE
1677 for defining speed and slave address
1678 - activate second bus with I2C_SOFT_DECLARATIONS2 define
1679 CONFIG_SYS_I2C_SOFT_SPEED_2 and CONFIG_SYS_I2C_SOFT_SLAVE_2
1680 for defining speed and slave address
1681 - activate third bus with I2C_SOFT_DECLARATIONS3 define
1682 CONFIG_SYS_I2C_SOFT_SPEED_3 and CONFIG_SYS_I2C_SOFT_SLAVE_3
1683 for defining speed and slave address
1684 - activate fourth bus with I2C_SOFT_DECLARATIONS4 define
1685 CONFIG_SYS_I2C_SOFT_SPEED_4 and CONFIG_SYS_I2C_SOFT_SLAVE_4
1686 for defining speed and slave address
1688 - drivers/i2c/fsl_i2c.c:
1689 - activate i2c driver with CONFIG_SYS_I2C_FSL
1690 define CONFIG_SYS_FSL_I2C_OFFSET for setting the register
1691 offset CONFIG_SYS_FSL_I2C_SPEED for the i2c speed and
1692 CONFIG_SYS_FSL_I2C_SLAVE for the slave addr of the first
1694 - If your board supports a second fsl i2c bus, define
1695 CONFIG_SYS_FSL_I2C2_OFFSET for the register offset
1696 CONFIG_SYS_FSL_I2C2_SPEED for the speed and
1697 CONFIG_SYS_FSL_I2C2_SLAVE for the slave address of the
1700 - drivers/i2c/tegra_i2c.c:
1701 - activate this driver with CONFIG_SYS_I2C_TEGRA
1702 - This driver adds 4 i2c buses with a fix speed from
1703 100000 and the slave addr 0!
1705 - drivers/i2c/ppc4xx_i2c.c
1706 - activate this driver with CONFIG_SYS_I2C_PPC4XX
1707 - CONFIG_SYS_I2C_PPC4XX_CH0 activate hardware channel 0
1708 - CONFIG_SYS_I2C_PPC4XX_CH1 activate hardware channel 1
1710 - drivers/i2c/i2c_mxc.c
1711 - activate this driver with CONFIG_SYS_I2C_MXC
1712 - enable bus 1 with CONFIG_SYS_I2C_MXC_I2C1
1713 - enable bus 2 with CONFIG_SYS_I2C_MXC_I2C2
1714 - enable bus 3 with CONFIG_SYS_I2C_MXC_I2C3
1715 - enable bus 4 with CONFIG_SYS_I2C_MXC_I2C4
1716 - define speed for bus 1 with CONFIG_SYS_MXC_I2C1_SPEED
1717 - define slave for bus 1 with CONFIG_SYS_MXC_I2C1_SLAVE
1718 - define speed for bus 2 with CONFIG_SYS_MXC_I2C2_SPEED
1719 - define slave for bus 2 with CONFIG_SYS_MXC_I2C2_SLAVE
1720 - define speed for bus 3 with CONFIG_SYS_MXC_I2C3_SPEED
1721 - define slave for bus 3 with CONFIG_SYS_MXC_I2C3_SLAVE
1722 - define speed for bus 4 with CONFIG_SYS_MXC_I2C4_SPEED
1723 - define slave for bus 4 with CONFIG_SYS_MXC_I2C4_SLAVE
1724 If those defines are not set, default value is 100000
1725 for speed, and 0 for slave.
1727 - drivers/i2c/rcar_i2c.c:
1728 - activate this driver with CONFIG_SYS_I2C_RCAR
1729 - This driver adds 4 i2c buses
1731 - CONFIG_SYS_RCAR_I2C0_BASE for setting the register channel 0
1732 - CONFIG_SYS_RCAR_I2C0_SPEED for for the speed channel 0
1733 - CONFIG_SYS_RCAR_I2C1_BASE for setting the register channel 1
1734 - CONFIG_SYS_RCAR_I2C1_SPEED for for the speed channel 1
1735 - CONFIG_SYS_RCAR_I2C2_BASE for setting the register channel 2
1736 - CONFIG_SYS_RCAR_I2C2_SPEED for for the speed channel 2
1737 - CONFIG_SYS_RCAR_I2C3_BASE for setting the register channel 3
1738 - CONFIG_SYS_RCAR_I2C3_SPEED for for the speed channel 3
1739 - CONFIF_SYS_RCAR_I2C_NUM_CONTROLLERS for number of i2c buses
1741 - drivers/i2c/sh_i2c.c:
1742 - activate this driver with CONFIG_SYS_I2C_SH
1743 - This driver adds from 2 to 5 i2c buses
1745 - CONFIG_SYS_I2C_SH_BASE0 for setting the register channel 0
1746 - CONFIG_SYS_I2C_SH_SPEED0 for for the speed channel 0
1747 - CONFIG_SYS_I2C_SH_BASE1 for setting the register channel 1
1748 - CONFIG_SYS_I2C_SH_SPEED1 for for the speed channel 1
1749 - CONFIG_SYS_I2C_SH_BASE2 for setting the register channel 2
1750 - CONFIG_SYS_I2C_SH_SPEED2 for for the speed channel 2
1751 - CONFIG_SYS_I2C_SH_BASE3 for setting the register channel 3
1752 - CONFIG_SYS_I2C_SH_SPEED3 for for the speed channel 3
1753 - CONFIG_SYS_I2C_SH_BASE4 for setting the register channel 4
1754 - CONFIG_SYS_I2C_SH_SPEED4 for for the speed channel 4
1755 - CONFIG_SYS_I2C_SH_NUM_CONTROLLERS for number of i2c buses
1757 - drivers/i2c/omap24xx_i2c.c
1758 - activate this driver with CONFIG_SYS_I2C_OMAP24XX
1759 - CONFIG_SYS_OMAP24_I2C_SPEED speed channel 0
1760 - CONFIG_SYS_OMAP24_I2C_SLAVE slave addr channel 0
1761 - CONFIG_SYS_OMAP24_I2C_SPEED1 speed channel 1
1762 - CONFIG_SYS_OMAP24_I2C_SLAVE1 slave addr channel 1
1763 - CONFIG_SYS_OMAP24_I2C_SPEED2 speed channel 2
1764 - CONFIG_SYS_OMAP24_I2C_SLAVE2 slave addr channel 2
1765 - CONFIG_SYS_OMAP24_I2C_SPEED3 speed channel 3
1766 - CONFIG_SYS_OMAP24_I2C_SLAVE3 slave addr channel 3
1767 - CONFIG_SYS_OMAP24_I2C_SPEED4 speed channel 4
1768 - CONFIG_SYS_OMAP24_I2C_SLAVE4 slave addr channel 4
1770 - drivers/i2c/zynq_i2c.c
1771 - activate this driver with CONFIG_SYS_I2C_ZYNQ
1772 - set CONFIG_SYS_I2C_ZYNQ_SPEED for speed setting
1773 - set CONFIG_SYS_I2C_ZYNQ_SLAVE for slave addr
1775 - drivers/i2c/s3c24x0_i2c.c:
1776 - activate this driver with CONFIG_SYS_I2C_S3C24X0
1777 - This driver adds i2c buses (11 for Exynos5250, Exynos5420
1778 9 i2c buses for Exynos4 and 1 for S3C24X0 SoCs from Samsung)
1779 with a fix speed from 100000 and the slave addr 0!
1781 - drivers/i2c/ihs_i2c.c
1782 - activate this driver with CONFIG_SYS_I2C_IHS
1783 - CONFIG_SYS_I2C_IHS_CH0 activate hardware channel 0
1784 - CONFIG_SYS_I2C_IHS_SPEED_0 speed channel 0
1785 - CONFIG_SYS_I2C_IHS_SLAVE_0 slave addr channel 0
1786 - CONFIG_SYS_I2C_IHS_CH1 activate hardware channel 1
1787 - CONFIG_SYS_I2C_IHS_SPEED_1 speed channel 1
1788 - CONFIG_SYS_I2C_IHS_SLAVE_1 slave addr channel 1
1789 - CONFIG_SYS_I2C_IHS_CH2 activate hardware channel 2
1790 - CONFIG_SYS_I2C_IHS_SPEED_2 speed channel 2
1791 - CONFIG_SYS_I2C_IHS_SLAVE_2 slave addr channel 2
1792 - CONFIG_SYS_I2C_IHS_CH3 activate hardware channel 3
1793 - CONFIG_SYS_I2C_IHS_SPEED_3 speed channel 3
1794 - CONFIG_SYS_I2C_IHS_SLAVE_3 slave addr channel 3
1795 - activate dual channel with CONFIG_SYS_I2C_IHS_DUAL
1796 - CONFIG_SYS_I2C_IHS_SPEED_0_1 speed channel 0_1
1797 - CONFIG_SYS_I2C_IHS_SLAVE_0_1 slave addr channel 0_1
1798 - CONFIG_SYS_I2C_IHS_SPEED_1_1 speed channel 1_1
1799 - CONFIG_SYS_I2C_IHS_SLAVE_1_1 slave addr channel 1_1
1800 - CONFIG_SYS_I2C_IHS_SPEED_2_1 speed channel 2_1
1801 - CONFIG_SYS_I2C_IHS_SLAVE_2_1 slave addr channel 2_1
1802 - CONFIG_SYS_I2C_IHS_SPEED_3_1 speed channel 3_1
1803 - CONFIG_SYS_I2C_IHS_SLAVE_3_1 slave addr channel 3_1
1807 CONFIG_SYS_NUM_I2C_BUSES
1808 Hold the number of i2c buses you want to use.
1810 CONFIG_SYS_I2C_DIRECT_BUS
1811 define this, if you don't use i2c muxes on your hardware.
1812 if CONFIG_SYS_I2C_MAX_HOPS is not defined or == 0 you can
1815 CONFIG_SYS_I2C_MAX_HOPS
1816 define how many muxes are maximal consecutively connected
1817 on one i2c bus. If you not use i2c muxes, omit this
1820 CONFIG_SYS_I2C_BUSES
1821 hold a list of buses you want to use, only used if
1822 CONFIG_SYS_I2C_DIRECT_BUS is not defined, for example
1823 a board with CONFIG_SYS_I2C_MAX_HOPS = 1 and
1824 CONFIG_SYS_NUM_I2C_BUSES = 9:
1826 CONFIG_SYS_I2C_BUSES {{0, {I2C_NULL_HOP}}, \
1827 {0, {{I2C_MUX_PCA9547, 0x70, 1}}}, \
1828 {0, {{I2C_MUX_PCA9547, 0x70, 2}}}, \
1829 {0, {{I2C_MUX_PCA9547, 0x70, 3}}}, \
1830 {0, {{I2C_MUX_PCA9547, 0x70, 4}}}, \
1831 {0, {{I2C_MUX_PCA9547, 0x70, 5}}}, \
1832 {1, {I2C_NULL_HOP}}, \
1833 {1, {{I2C_MUX_PCA9544, 0x72, 1}}}, \
1834 {1, {{I2C_MUX_PCA9544, 0x72, 2}}}, \
1838 bus 0 on adapter 0 without a mux
1839 bus 1 on adapter 0 with a PCA9547 on address 0x70 port 1
1840 bus 2 on adapter 0 with a PCA9547 on address 0x70 port 2
1841 bus 3 on adapter 0 with a PCA9547 on address 0x70 port 3
1842 bus 4 on adapter 0 with a PCA9547 on address 0x70 port 4
1843 bus 5 on adapter 0 with a PCA9547 on address 0x70 port 5
1844 bus 6 on adapter 1 without a mux
1845 bus 7 on adapter 1 with a PCA9544 on address 0x72 port 1
1846 bus 8 on adapter 1 with a PCA9544 on address 0x72 port 2
1848 If you do not have i2c muxes on your board, omit this define.
1850 - Legacy I2C Support:
1851 If you use the software i2c interface (CONFIG_SYS_I2C_SOFT)
1852 then the following macros need to be defined (examples are
1853 from include/configs/lwmon.h):
1857 (Optional). Any commands necessary to enable the I2C
1858 controller or configure ports.
1860 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1864 The code necessary to make the I2C data line active
1865 (driven). If the data line is open collector, this
1868 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1872 The code necessary to make the I2C data line tri-stated
1873 (inactive). If the data line is open collector, this
1876 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1880 Code that returns true if the I2C data line is high,
1883 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1887 If <bit> is true, sets the I2C data line high. If it
1888 is false, it clears it (low).
1890 eg: #define I2C_SDA(bit) \
1891 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1892 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1896 If <bit> is true, sets the I2C clock line high. If it
1897 is false, it clears it (low).
1899 eg: #define I2C_SCL(bit) \
1900 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1901 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1905 This delay is invoked four times per clock cycle so this
1906 controls the rate of data transfer. The data rate thus
1907 is 1 / (I2C_DELAY * 4). Often defined to be something
1910 #define I2C_DELAY udelay(2)
1912 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
1914 If your arch supports the generic GPIO framework (asm/gpio.h),
1915 then you may alternatively define the two GPIOs that are to be
1916 used as SCL / SDA. Any of the previous I2C_xxx macros will
1917 have GPIO-based defaults assigned to them as appropriate.
1919 You should define these to the GPIO value as given directly to
1920 the generic GPIO functions.
1922 CONFIG_SYS_I2C_INIT_BOARD
1924 When a board is reset during an i2c bus transfer
1925 chips might think that the current transfer is still
1926 in progress. On some boards it is possible to access
1927 the i2c SCLK line directly, either by using the
1928 processor pin as a GPIO or by having a second pin
1929 connected to the bus. If this option is defined a
1930 custom i2c_init_board() routine in boards/xxx/board.c
1931 is run early in the boot sequence.
1933 CONFIG_I2C_MULTI_BUS
1935 This option allows the use of multiple I2C buses, each of which
1936 must have a controller. At any point in time, only one bus is
1937 active. To switch to a different bus, use the 'i2c dev' command.
1938 Note that bus numbering is zero-based.
1940 CONFIG_SYS_I2C_NOPROBES
1942 This option specifies a list of I2C devices that will be skipped
1943 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
1944 is set, specify a list of bus-device pairs. Otherwise, specify
1945 a 1D array of device addresses
1948 #undef CONFIG_I2C_MULTI_BUS
1949 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
1951 will skip addresses 0x50 and 0x68 on a board with one I2C bus
1953 #define CONFIG_I2C_MULTI_BUS
1954 #define CONFIG_SYS_I2C_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
1956 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
1958 CONFIG_SYS_SPD_BUS_NUM
1960 If defined, then this indicates the I2C bus number for DDR SPD.
1961 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
1963 CONFIG_SYS_RTC_BUS_NUM
1965 If defined, then this indicates the I2C bus number for the RTC.
1966 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
1968 CONFIG_SOFT_I2C_READ_REPEATED_START
1970 defining this will force the i2c_read() function in
1971 the soft_i2c driver to perform an I2C repeated start
1972 between writing the address pointer and reading the
1973 data. If this define is omitted the default behaviour
1974 of doing a stop-start sequence will be used. Most I2C
1975 devices can use either method, but some require one or
1978 - SPI Support: CONFIG_SPI
1980 Enables SPI driver (so far only tested with
1981 SPI EEPROM, also an instance works with Crystal A/D and
1982 D/As on the SACSng board)
1986 Enables a software (bit-bang) SPI driver rather than
1987 using hardware support. This is a general purpose
1988 driver that only requires three general I/O port pins
1989 (two outputs, one input) to function. If this is
1990 defined, the board configuration must define several
1991 SPI configuration items (port pins to use, etc). For
1992 an example, see include/configs/sacsng.h.
1996 Enables a hardware SPI driver for general-purpose reads
1997 and writes. As with CONFIG_SOFT_SPI, the board configuration
1998 must define a list of chip-select function pointers.
1999 Currently supported on some MPC8xxx processors. For an
2000 example, see include/configs/mpc8349emds.h.
2002 CONFIG_SYS_SPI_MXC_WAIT
2003 Timeout for waiting until spi transfer completed.
2004 default: (CONFIG_SYS_HZ/100) /* 10 ms */
2006 - FPGA Support: CONFIG_FPGA
2008 Enables FPGA subsystem.
2010 CONFIG_FPGA_<vendor>
2012 Enables support for specific chip vendors.
2015 CONFIG_FPGA_<family>
2017 Enables support for FPGA family.
2018 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
2022 Specify the number of FPGA devices to support.
2024 CONFIG_SYS_FPGA_PROG_FEEDBACK
2026 Enable printing of hash marks during FPGA configuration.
2028 CONFIG_SYS_FPGA_CHECK_BUSY
2030 Enable checks on FPGA configuration interface busy
2031 status by the configuration function. This option
2032 will require a board or device specific function to
2037 If defined, a function that provides delays in the FPGA
2038 configuration driver.
2040 CONFIG_SYS_FPGA_CHECK_CTRLC
2041 Allow Control-C to interrupt FPGA configuration
2043 CONFIG_SYS_FPGA_CHECK_ERROR
2045 Check for configuration errors during FPGA bitfile
2046 loading. For example, abort during Virtex II
2047 configuration if the INIT_B line goes low (which
2048 indicated a CRC error).
2050 CONFIG_SYS_FPGA_WAIT_INIT
2052 Maximum time to wait for the INIT_B line to de-assert
2053 after PROB_B has been de-asserted during a Virtex II
2054 FPGA configuration sequence. The default time is 500
2057 CONFIG_SYS_FPGA_WAIT_BUSY
2059 Maximum time to wait for BUSY to de-assert during
2060 Virtex II FPGA configuration. The default is 5 ms.
2062 CONFIG_SYS_FPGA_WAIT_CONFIG
2064 Time to wait after FPGA configuration. The default is
2067 - Configuration Management:
2070 Some SoCs need special image types (e.g. U-Boot binary
2071 with a special header) as build targets. By defining
2072 CONFIG_BUILD_TARGET in the SoC / board header, this
2073 special image will be automatically built upon calling
2078 If defined, this string will be added to the U-Boot
2079 version information (U_BOOT_VERSION)
2081 - Vendor Parameter Protection:
2083 U-Boot considers the values of the environment
2084 variables "serial#" (Board Serial Number) and
2085 "ethaddr" (Ethernet Address) to be parameters that
2086 are set once by the board vendor / manufacturer, and
2087 protects these variables from casual modification by
2088 the user. Once set, these variables are read-only,
2089 and write or delete attempts are rejected. You can
2090 change this behaviour:
2092 If CONFIG_ENV_OVERWRITE is #defined in your config
2093 file, the write protection for vendor parameters is
2094 completely disabled. Anybody can change or delete
2097 Alternatively, if you define _both_ an ethaddr in the
2098 default env _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2099 Ethernet address is installed in the environment,
2100 which can be changed exactly ONCE by the user. [The
2101 serial# is unaffected by this, i. e. it remains
2104 The same can be accomplished in a more flexible way
2105 for any variable by configuring the type of access
2106 to allow for those variables in the ".flags" variable
2107 or define CONFIG_ENV_FLAGS_LIST_STATIC.
2112 Define this variable to enable the reservation of
2113 "protected RAM", i. e. RAM which is not overwritten
2114 by U-Boot. Define CONFIG_PRAM to hold the number of
2115 kB you want to reserve for pRAM. You can overwrite
2116 this default value by defining an environment
2117 variable "pram" to the number of kB you want to
2118 reserve. Note that the board info structure will
2119 still show the full amount of RAM. If pRAM is
2120 reserved, a new environment variable "mem" will
2121 automatically be defined to hold the amount of
2122 remaining RAM in a form that can be passed as boot
2123 argument to Linux, for instance like that:
2125 setenv bootargs ... mem=\${mem}
2128 This way you can tell Linux not to use this memory,
2129 either, which results in a memory region that will
2130 not be affected by reboots.
2132 *WARNING* If your board configuration uses automatic
2133 detection of the RAM size, you must make sure that
2134 this memory test is non-destructive. So far, the
2135 following board configurations are known to be
2138 IVMS8, IVML24, SPD8xx,
2139 HERMES, IP860, RPXlite, LWMON,
2142 - Access to physical memory region (> 4GB)
2143 Some basic support is provided for operations on memory not
2144 normally accessible to U-Boot - e.g. some architectures
2145 support access to more than 4GB of memory on 32-bit
2146 machines using physical address extension or similar.
2147 Define CONFIG_PHYSMEM to access this basic support, which
2148 currently only supports clearing the memory.
2151 CONFIG_NET_RETRY_COUNT
2153 This variable defines the number of retries for
2154 network operations like ARP, RARP, TFTP, or BOOTP
2155 before giving up the operation. If not defined, a
2156 default value of 5 is used.
2160 Timeout waiting for an ARP reply in milliseconds.
2164 Timeout in milliseconds used in NFS protocol.
2165 If you encounter "ERROR: Cannot umount" in nfs command,
2166 try longer timeout such as
2167 #define CONFIG_NFS_TIMEOUT 10000UL
2169 - Command Interpreter:
2170 CONFIG_SYS_PROMPT_HUSH_PS2
2172 This defines the secondary prompt string, which is
2173 printed when the command interpreter needs more input
2174 to complete a command. Usually "> ".
2178 In the current implementation, the local variables
2179 space and global environment variables space are
2180 separated. Local variables are those you define by
2181 simply typing `name=value'. To access a local
2182 variable later on, you have write `$name' or
2183 `${name}'; to execute the contents of a variable
2184 directly type `$name' at the command prompt.
2186 Global environment variables are those you use
2187 setenv/printenv to work with. To run a command stored
2188 in such a variable, you need to use the run command,
2189 and you must not use the '$' sign to access them.
2191 To store commands and special characters in a
2192 variable, please use double quotation marks
2193 surrounding the whole text of the variable, instead
2194 of the backslashes before semicolons and special
2197 - Command Line Editing and History:
2198 CONFIG_CMDLINE_PS_SUPPORT
2200 Enable support for changing the command prompt string
2201 at run-time. Only static string is supported so far.
2202 The string is obtained from environment variables PS1
2205 - Default Environment:
2206 CONFIG_EXTRA_ENV_SETTINGS
2208 Define this to contain any number of null terminated
2209 strings (variable = value pairs) that will be part of
2210 the default environment compiled into the boot image.
2212 For example, place something like this in your
2213 board's config file:
2215 #define CONFIG_EXTRA_ENV_SETTINGS \
2219 Warning: This method is based on knowledge about the
2220 internal format how the environment is stored by the
2221 U-Boot code. This is NOT an official, exported
2222 interface! Although it is unlikely that this format
2223 will change soon, there is no guarantee either.
2224 You better know what you are doing here.
2226 Note: overly (ab)use of the default environment is
2227 discouraged. Make sure to check other ways to preset
2228 the environment like the "source" command or the
2231 CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG
2233 Define this in order to add variables describing certain
2234 run-time determined information about the hardware to the
2235 environment. These will be named board_name, board_rev.
2237 CONFIG_DELAY_ENVIRONMENT
2239 Normally the environment is loaded when the board is
2240 initialised so that it is available to U-Boot. This inhibits
2241 that so that the environment is not available until
2242 explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL
2243 this is instead controlled by the value of
2244 /config/load-environment.
2246 - Serial Flash support
2247 Usage requires an initial 'sf probe' to define the serial
2248 flash parameters, followed by read/write/erase/update
2251 The following defaults may be provided by the platform
2252 to handle the common case when only a single serial
2253 flash is present on the system.
2255 CONFIG_SF_DEFAULT_BUS Bus identifier
2256 CONFIG_SF_DEFAULT_CS Chip-select
2257 CONFIG_SF_DEFAULT_MODE (see include/spi.h)
2258 CONFIG_SF_DEFAULT_SPEED in Hz
2261 - TFTP Fixed UDP Port:
2264 If this is defined, the environment variable tftpsrcp
2265 is used to supply the TFTP UDP source port value.
2266 If tftpsrcp isn't defined, the normal pseudo-random port
2267 number generator is used.
2269 Also, the environment variable tftpdstp is used to supply
2270 the TFTP UDP destination port value. If tftpdstp isn't
2271 defined, the normal port 69 is used.
2273 The purpose for tftpsrcp is to allow a TFTP server to
2274 blindly start the TFTP transfer using the pre-configured
2275 target IP address and UDP port. This has the effect of
2276 "punching through" the (Windows XP) firewall, allowing
2277 the remainder of the TFTP transfer to proceed normally.
2278 A better solution is to properly configure the firewall,
2279 but sometimes that is not allowed.
2281 - bootcount support:
2283 enable special bootcounter support on at91sam9xe based boards.
2284 CONFIG_BOOTCOUNT_RAM
2285 enable support for the bootcounter in RAM
2286 CONFIG_BOOTCOUNT_I2C
2287 enable support for the bootcounter on an i2c (like RTC) device.
2288 CONFIG_SYS_I2C_RTC_ADDR = i2c chip address
2289 CONFIG_SYS_BOOTCOUNT_ADDR = i2c addr which is used for
2291 CONFIG_BOOTCOUNT_ALEN = address len
2292 CONFIG_BOOTCOUNT_EXT
2293 enable support for the bootcounter in EXT filesystem
2294 CONFIG_SYS_BOOTCOUNT_ADDR = RAM address used for read
2296 CONFIG_SYS_BOOTCOUNT_EXT_INTERFACE = interface
2297 CONFIG_SYS_BOOTCOUNT_EXT_DEVPART = device and part
2298 CONFIG_SYS_BOOTCOUNT_EXT_NAME = filename
2300 - Show boot progress:
2301 CONFIG_SHOW_BOOT_PROGRESS
2303 Defining this option allows to add some board-
2304 specific code (calling a user-provided function
2305 "show_boot_progress(int)") that enables you to show
2306 the system's boot progress on some display (for
2307 example, some LED's) on your board. At the moment,
2308 the following checkpoints are implemented:
2311 Legacy uImage format:
2314 1 common/cmd_bootm.c before attempting to boot an image
2315 -1 common/cmd_bootm.c Image header has bad magic number
2316 2 common/cmd_bootm.c Image header has correct magic number
2317 -2 common/cmd_bootm.c Image header has bad checksum
2318 3 common/cmd_bootm.c Image header has correct checksum
2319 -3 common/cmd_bootm.c Image data has bad checksum
2320 4 common/cmd_bootm.c Image data has correct checksum
2321 -4 common/cmd_bootm.c Image is for unsupported architecture
2322 5 common/cmd_bootm.c Architecture check OK
2323 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
2324 6 common/cmd_bootm.c Image Type check OK
2325 -6 common/cmd_bootm.c gunzip uncompression error
2326 -7 common/cmd_bootm.c Unimplemented compression type
2327 7 common/cmd_bootm.c Uncompression OK
2328 8 common/cmd_bootm.c No uncompress/copy overwrite error
2329 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
2331 9 common/image.c Start initial ramdisk verification
2332 -10 common/image.c Ramdisk header has bad magic number
2333 -11 common/image.c Ramdisk header has bad checksum
2334 10 common/image.c Ramdisk header is OK
2335 -12 common/image.c Ramdisk data has bad checksum
2336 11 common/image.c Ramdisk data has correct checksum
2337 12 common/image.c Ramdisk verification complete, start loading
2338 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
2339 13 common/image.c Start multifile image verification
2340 14 common/image.c No initial ramdisk, no multifile, continue.
2342 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
2344 -30 arch/powerpc/lib/board.c Fatal error, hang the system
2345 -31 post/post.c POST test failed, detected by post_output_backlog()
2346 -32 post/post.c POST test failed, detected by post_run_single()
2348 34 common/cmd_doc.c before loading a Image from a DOC device
2349 -35 common/cmd_doc.c Bad usage of "doc" command
2350 35 common/cmd_doc.c correct usage of "doc" command
2351 -36 common/cmd_doc.c No boot device
2352 36 common/cmd_doc.c correct boot device
2353 -37 common/cmd_doc.c Unknown Chip ID on boot device
2354 37 common/cmd_doc.c correct chip ID found, device available
2355 -38 common/cmd_doc.c Read Error on boot device
2356 38 common/cmd_doc.c reading Image header from DOC device OK
2357 -39 common/cmd_doc.c Image header has bad magic number
2358 39 common/cmd_doc.c Image header has correct magic number
2359 -40 common/cmd_doc.c Error reading Image from DOC device
2360 40 common/cmd_doc.c Image header has correct magic number
2361 41 common/cmd_ide.c before loading a Image from a IDE device
2362 -42 common/cmd_ide.c Bad usage of "ide" command
2363 42 common/cmd_ide.c correct usage of "ide" command
2364 -43 common/cmd_ide.c No boot device
2365 43 common/cmd_ide.c boot device found
2366 -44 common/cmd_ide.c Device not available
2367 44 common/cmd_ide.c Device available
2368 -45 common/cmd_ide.c wrong partition selected
2369 45 common/cmd_ide.c partition selected
2370 -46 common/cmd_ide.c Unknown partition table
2371 46 common/cmd_ide.c valid partition table found
2372 -47 common/cmd_ide.c Invalid partition type
2373 47 common/cmd_ide.c correct partition type
2374 -48 common/cmd_ide.c Error reading Image Header on boot device
2375 48 common/cmd_ide.c reading Image Header from IDE device OK
2376 -49 common/cmd_ide.c Image header has bad magic number
2377 49 common/cmd_ide.c Image header has correct magic number
2378 -50 common/cmd_ide.c Image header has bad checksum
2379 50 common/cmd_ide.c Image header has correct checksum
2380 -51 common/cmd_ide.c Error reading Image from IDE device
2381 51 common/cmd_ide.c reading Image from IDE device OK
2382 52 common/cmd_nand.c before loading a Image from a NAND device
2383 -53 common/cmd_nand.c Bad usage of "nand" command
2384 53 common/cmd_nand.c correct usage of "nand" command
2385 -54 common/cmd_nand.c No boot device
2386 54 common/cmd_nand.c boot device found
2387 -55 common/cmd_nand.c Unknown Chip ID on boot device
2388 55 common/cmd_nand.c correct chip ID found, device available
2389 -56 common/cmd_nand.c Error reading Image Header on boot device
2390 56 common/cmd_nand.c reading Image Header from NAND device OK
2391 -57 common/cmd_nand.c Image header has bad magic number
2392 57 common/cmd_nand.c Image header has correct magic number
2393 -58 common/cmd_nand.c Error reading Image from NAND device
2394 58 common/cmd_nand.c reading Image from NAND device OK
2396 -60 common/env_common.c Environment has a bad CRC, using default
2398 64 net/eth.c starting with Ethernet configuration.
2399 -64 net/eth.c no Ethernet found.
2400 65 net/eth.c Ethernet found.
2402 -80 common/cmd_net.c usage wrong
2403 80 common/cmd_net.c before calling net_loop()
2404 -81 common/cmd_net.c some error in net_loop() occurred
2405 81 common/cmd_net.c net_loop() back without error
2406 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
2407 82 common/cmd_net.c trying automatic boot
2408 83 common/cmd_net.c running "source" command
2409 -83 common/cmd_net.c some error in automatic boot or "source" command
2410 84 common/cmd_net.c end without errors
2415 100 common/cmd_bootm.c Kernel FIT Image has correct format
2416 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
2417 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
2418 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
2419 102 common/cmd_bootm.c Kernel unit name specified
2420 -103 common/cmd_bootm.c Can't get kernel subimage node offset
2421 103 common/cmd_bootm.c Found configuration node
2422 104 common/cmd_bootm.c Got kernel subimage node offset
2423 -104 common/cmd_bootm.c Kernel subimage hash verification failed
2424 105 common/cmd_bootm.c Kernel subimage hash verification OK
2425 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
2426 106 common/cmd_bootm.c Architecture check OK
2427 -106 common/cmd_bootm.c Kernel subimage has wrong type
2428 107 common/cmd_bootm.c Kernel subimage type OK
2429 -107 common/cmd_bootm.c Can't get kernel subimage data/size
2430 108 common/cmd_bootm.c Got kernel subimage data/size
2431 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
2432 -109 common/cmd_bootm.c Can't get kernel subimage type
2433 -110 common/cmd_bootm.c Can't get kernel subimage comp
2434 -111 common/cmd_bootm.c Can't get kernel subimage os
2435 -112 common/cmd_bootm.c Can't get kernel subimage load address
2436 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
2438 120 common/image.c Start initial ramdisk verification
2439 -120 common/image.c Ramdisk FIT image has incorrect format
2440 121 common/image.c Ramdisk FIT image has correct format
2441 122 common/image.c No ramdisk subimage unit name, using configuration
2442 -122 common/image.c Can't get configuration for ramdisk subimage
2443 123 common/image.c Ramdisk unit name specified
2444 -124 common/image.c Can't get ramdisk subimage node offset
2445 125 common/image.c Got ramdisk subimage node offset
2446 -125 common/image.c Ramdisk subimage hash verification failed
2447 126 common/image.c Ramdisk subimage hash verification OK
2448 -126 common/image.c Ramdisk subimage for unsupported architecture
2449 127 common/image.c Architecture check OK
2450 -127 common/image.c Can't get ramdisk subimage data/size
2451 128 common/image.c Got ramdisk subimage data/size
2452 129 common/image.c Can't get ramdisk load address
2453 -129 common/image.c Got ramdisk load address
2455 -130 common/cmd_doc.c Incorrect FIT image format
2456 131 common/cmd_doc.c FIT image format OK
2458 -140 common/cmd_ide.c Incorrect FIT image format
2459 141 common/cmd_ide.c FIT image format OK
2461 -150 common/cmd_nand.c Incorrect FIT image format
2462 151 common/cmd_nand.c FIT image format OK
2464 - legacy image format:
2465 CONFIG_IMAGE_FORMAT_LEGACY
2466 enables the legacy image format support in U-Boot.
2469 enabled if CONFIG_FIT_SIGNATURE is not defined.
2471 CONFIG_DISABLE_IMAGE_LEGACY
2472 disable the legacy image format
2474 This define is introduced, as the legacy image format is
2475 enabled per default for backward compatibility.
2477 - Standalone program support:
2478 CONFIG_STANDALONE_LOAD_ADDR
2480 This option defines a board specific value for the
2481 address where standalone program gets loaded, thus
2482 overwriting the architecture dependent default
2485 - Frame Buffer Address:
2488 Define CONFIG_FB_ADDR if you want to use specific
2489 address for frame buffer. This is typically the case
2490 when using a graphics controller has separate video
2491 memory. U-Boot will then place the frame buffer at
2492 the given address instead of dynamically reserving it
2493 in system RAM by calling lcd_setmem(), which grabs
2494 the memory for the frame buffer depending on the
2495 configured panel size.
2497 Please see board_init_f function.
2499 - Automatic software updates via TFTP server
2501 CONFIG_UPDATE_TFTP_CNT_MAX
2502 CONFIG_UPDATE_TFTP_MSEC_MAX
2504 These options enable and control the auto-update feature;
2505 for a more detailed description refer to doc/README.update.
2507 - MTD Support (mtdparts command, UBI support)
2510 Adds the MTD device infrastructure from the Linux kernel.
2511 Needed for mtdparts command support.
2513 CONFIG_MTD_PARTITIONS
2515 Adds the MTD partitioning infrastructure from the Linux
2516 kernel. Needed for UBI support.
2519 CONFIG_UBI_SILENCE_MSG
2521 Make the verbose messages from UBI stop printing. This leaves
2522 warnings and errors enabled.
2525 CONFIG_MTD_UBI_WL_THRESHOLD
2526 This parameter defines the maximum difference between the highest
2527 erase counter value and the lowest erase counter value of eraseblocks
2528 of UBI devices. When this threshold is exceeded, UBI starts performing
2529 wear leveling by means of moving data from eraseblock with low erase
2530 counter to eraseblocks with high erase counter.
2532 The default value should be OK for SLC NAND flashes, NOR flashes and
2533 other flashes which have eraseblock life-cycle 100000 or more.
2534 However, in case of MLC NAND flashes which typically have eraseblock
2535 life-cycle less than 10000, the threshold should be lessened (e.g.,
2536 to 128 or 256, although it does not have to be power of 2).
2540 CONFIG_MTD_UBI_BEB_LIMIT
2541 This option specifies the maximum bad physical eraseblocks UBI
2542 expects on the MTD device (per 1024 eraseblocks). If the
2543 underlying flash does not admit of bad eraseblocks (e.g. NOR
2544 flash), this value is ignored.
2546 NAND datasheets often specify the minimum and maximum NVM
2547 (Number of Valid Blocks) for the flashes' endurance lifetime.
2548 The maximum expected bad eraseblocks per 1024 eraseblocks
2549 then can be calculated as "1024 * (1 - MinNVB / MaxNVB)",
2550 which gives 20 for most NANDs (MaxNVB is basically the total
2551 count of eraseblocks on the chip).
2553 To put it differently, if this value is 20, UBI will try to
2554 reserve about 1.9% of physical eraseblocks for bad blocks
2555 handling. And that will be 1.9% of eraseblocks on the entire
2556 NAND chip, not just the MTD partition UBI attaches. This means
2557 that if you have, say, a NAND flash chip admits maximum 40 bad
2558 eraseblocks, and it is split on two MTD partitions of the same
2559 size, UBI will reserve 40 eraseblocks when attaching a
2564 CONFIG_MTD_UBI_FASTMAP
2565 Fastmap is a mechanism which allows attaching an UBI device
2566 in nearly constant time. Instead of scanning the whole MTD device it
2567 only has to locate a checkpoint (called fastmap) on the device.
2568 The on-flash fastmap contains all information needed to attach
2569 the device. Using fastmap makes only sense on large devices where
2570 attaching by scanning takes long. UBI will not automatically install
2571 a fastmap on old images, but you can set the UBI parameter
2572 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT to 1 if you want so. Please note
2573 that fastmap-enabled images are still usable with UBI implementations
2574 without fastmap support. On typical flash devices the whole fastmap
2575 fits into one PEB. UBI will reserve PEBs to hold two fastmaps.
2577 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT
2578 Set this parameter to enable fastmap automatically on images
2582 CONFIG_MTD_UBI_FM_DEBUG
2583 Enable UBI fastmap debug
2587 CONFIG_UBIFS_SILENCE_MSG
2589 Make the verbose messages from UBIFS stop printing. This leaves
2590 warnings and errors enabled.
2594 Enable building of SPL globally.
2597 LDSCRIPT for linking the SPL binary.
2599 CONFIG_SPL_MAX_FOOTPRINT
2600 Maximum size in memory allocated to the SPL, BSS included.
2601 When defined, the linker checks that the actual memory
2602 used by SPL from _start to __bss_end does not exceed it.
2603 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
2604 must not be both defined at the same time.
2607 Maximum size of the SPL image (text, data, rodata, and
2608 linker lists sections), BSS excluded.
2609 When defined, the linker checks that the actual size does
2612 CONFIG_SPL_TEXT_BASE
2613 TEXT_BASE for linking the SPL binary.
2615 CONFIG_SPL_RELOC_TEXT_BASE
2616 Address to relocate to. If unspecified, this is equal to
2617 CONFIG_SPL_TEXT_BASE (i.e. no relocation is done).
2619 CONFIG_SPL_BSS_START_ADDR
2620 Link address for the BSS within the SPL binary.
2622 CONFIG_SPL_BSS_MAX_SIZE
2623 Maximum size in memory allocated to the SPL BSS.
2624 When defined, the linker checks that the actual memory used
2625 by SPL from __bss_start to __bss_end does not exceed it.
2626 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
2627 must not be both defined at the same time.
2630 Adress of the start of the stack SPL will use
2632 CONFIG_SPL_PANIC_ON_RAW_IMAGE
2633 When defined, SPL will panic() if the image it has
2634 loaded does not have a signature.
2635 Defining this is useful when code which loads images
2636 in SPL cannot guarantee that absolutely all read errors
2638 An example is the LPC32XX MLC NAND driver, which will
2639 consider that a completely unreadable NAND block is bad,
2640 and thus should be skipped silently.
2642 CONFIG_SPL_RELOC_STACK
2643 Adress of the start of the stack SPL will use after
2644 relocation. If unspecified, this is equal to
2647 CONFIG_SYS_SPL_MALLOC_START
2648 Starting address of the malloc pool used in SPL.
2649 When this option is set the full malloc is used in SPL and
2650 it is set up by spl_init() and before that, the simple malloc()
2651 can be used if CONFIG_SYS_MALLOC_F is defined.
2653 CONFIG_SYS_SPL_MALLOC_SIZE
2654 The size of the malloc pool used in SPL.
2657 Enable booting directly to an OS from SPL.
2658 See also: doc/README.falcon
2660 CONFIG_SPL_DISPLAY_PRINT
2661 For ARM, enable an optional function to print more information
2662 about the running system.
2664 CONFIG_SPL_INIT_MINIMAL
2665 Arch init code should be built for a very small image
2667 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_PARTITION
2668 Partition on the MMC to load U-Boot from when the MMC is being
2671 CONFIG_SYS_MMCSD_RAW_MODE_KERNEL_SECTOR
2672 Sector to load kernel uImage from when MMC is being
2673 used in raw mode (for Falcon mode)
2675 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTOR,
2676 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTORS
2677 Sector and number of sectors to load kernel argument
2678 parameters from when MMC is being used in raw mode
2681 CONFIG_SYS_MMCSD_FS_BOOT_PARTITION
2682 Partition on the MMC to load U-Boot from when the MMC is being
2685 CONFIG_SPL_FS_LOAD_PAYLOAD_NAME
2686 Filename to read to load U-Boot when reading from filesystem
2688 CONFIG_SPL_FS_LOAD_KERNEL_NAME
2689 Filename to read to load kernel uImage when reading
2690 from filesystem (for Falcon mode)
2692 CONFIG_SPL_FS_LOAD_ARGS_NAME
2693 Filename to read to load kernel argument parameters
2694 when reading from filesystem (for Falcon mode)
2696 CONFIG_SPL_MPC83XX_WAIT_FOR_NAND
2697 Set this for NAND SPL on PPC mpc83xx targets, so that
2698 start.S waits for the rest of the SPL to load before
2699 continuing (the hardware starts execution after just
2700 loading the first page rather than the full 4K).
2702 CONFIG_SPL_SKIP_RELOCATE
2703 Avoid SPL relocation
2705 CONFIG_SPL_NAND_BASE
2706 Include nand_base.c in the SPL. Requires
2707 CONFIG_SPL_NAND_DRIVERS.
2709 CONFIG_SPL_NAND_DRIVERS
2710 SPL uses normal NAND drivers, not minimal drivers.
2713 Include standard software ECC in the SPL
2715 CONFIG_SPL_NAND_SIMPLE
2716 Support for NAND boot using simple NAND drivers that
2717 expose the cmd_ctrl() interface.
2720 Support for a lightweight UBI (fastmap) scanner and
2723 CONFIG_SPL_NAND_RAW_ONLY
2724 Support to boot only raw u-boot.bin images. Use this only
2725 if you need to save space.
2727 CONFIG_SPL_COMMON_INIT_DDR
2728 Set for common ddr init with serial presence detect in
2731 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
2732 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
2733 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
2734 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
2735 CONFIG_SYS_NAND_ECCBYTES
2736 Defines the size and behavior of the NAND that SPL uses
2739 CONFIG_SPL_NAND_BOOT
2740 Add support NAND boot
2742 CONFIG_SYS_NAND_U_BOOT_OFFS
2743 Location in NAND to read U-Boot from
2745 CONFIG_SYS_NAND_U_BOOT_DST
2746 Location in memory to load U-Boot to
2748 CONFIG_SYS_NAND_U_BOOT_SIZE
2749 Size of image to load
2751 CONFIG_SYS_NAND_U_BOOT_START
2752 Entry point in loaded image to jump to
2754 CONFIG_SYS_NAND_HW_ECC_OOBFIRST
2755 Define this if you need to first read the OOB and then the
2756 data. This is used, for example, on davinci platforms.
2758 CONFIG_SPL_RAM_DEVICE
2759 Support for running image already present in ram, in SPL binary
2762 Image offset to which the SPL should be padded before appending
2763 the SPL payload. By default, this is defined as
2764 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
2765 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
2766 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
2769 Final target image containing SPL and payload. Some SPLs
2770 use an arch-specific makefile fragment instead, for
2771 example if more than one image needs to be produced.
2773 CONFIG_FIT_SPL_PRINT
2774 Printing information about a FIT image adds quite a bit of
2775 code to SPL. So this is normally disabled in SPL. Use this
2776 option to re-enable it. This will affect the output of the
2777 bootm command when booting a FIT image.
2781 Enable building of TPL globally.
2784 Image offset to which the TPL should be padded before appending
2785 the TPL payload. By default, this is defined as
2786 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
2787 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
2788 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
2790 - Interrupt support (PPC):
2792 There are common interrupt_init() and timer_interrupt()
2793 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
2794 for CPU specific initialization. interrupt_init_cpu()
2795 should set decrementer_count to appropriate value. If
2796 CPU resets decrementer automatically after interrupt
2797 (ppc4xx) it should set decrementer_count to zero.
2798 timer_interrupt() calls timer_interrupt_cpu() for CPU
2799 specific handling. If board has watchdog / status_led
2800 / other_activity_monitor it works automatically from
2801 general timer_interrupt().
2804 Board initialization settings:
2805 ------------------------------
2807 During Initialization u-boot calls a number of board specific functions
2808 to allow the preparation of board specific prerequisites, e.g. pin setup
2809 before drivers are initialized. To enable these callbacks the
2810 following configuration macros have to be defined. Currently this is
2811 architecture specific, so please check arch/your_architecture/lib/board.c
2812 typically in board_init_f() and board_init_r().
2814 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
2815 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
2816 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
2817 - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
2819 Configuration Settings:
2820 -----------------------
2822 - CONFIG_SYS_SUPPORT_64BIT_DATA: Defined automatically if compiled as 64-bit.
2823 Optionally it can be defined to support 64-bit memory commands.
2825 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
2826 undefine this when you're short of memory.
2828 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
2829 width of the commands listed in the 'help' command output.
2831 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
2832 prompt for user input.
2834 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
2836 - CONFIG_SYS_PBSIZE: Buffer size for Console output
2838 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
2840 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
2841 the application (usually a Linux kernel) when it is
2844 - CONFIG_SYS_BAUDRATE_TABLE:
2845 List of legal baudrate settings for this board.
2847 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
2848 Begin and End addresses of the area used by the
2851 - CONFIG_SYS_ALT_MEMTEST:
2852 Enable an alternate, more extensive memory test.
2854 - CONFIG_SYS_MEMTEST_SCRATCH:
2855 Scratch address used by the alternate memory test
2856 You only need to set this if address zero isn't writeable
2858 - CONFIG_SYS_MEM_RESERVE_SECURE
2859 Only implemented for ARMv8 for now.
2860 If defined, the size of CONFIG_SYS_MEM_RESERVE_SECURE memory
2861 is substracted from total RAM and won't be reported to OS.
2862 This memory can be used as secure memory. A variable
2863 gd->arch.secure_ram is used to track the location. In systems
2864 the RAM base is not zero, or RAM is divided into banks,
2865 this variable needs to be recalcuated to get the address.
2867 - CONFIG_SYS_MEM_TOP_HIDE:
2868 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
2869 this specified memory area will get subtracted from the top
2870 (end) of RAM and won't get "touched" at all by U-Boot. By
2871 fixing up gd->ram_size the Linux kernel should gets passed
2872 the now "corrected" memory size and won't touch it either.
2873 This should work for arch/ppc and arch/powerpc. Only Linux
2874 board ports in arch/powerpc with bootwrapper support that
2875 recalculate the memory size from the SDRAM controller setup
2876 will have to get fixed in Linux additionally.
2878 This option can be used as a workaround for the 440EPx/GRx
2879 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
2882 WARNING: Please make sure that this value is a multiple of
2883 the Linux page size (normally 4k). If this is not the case,
2884 then the end address of the Linux memory will be located at a
2885 non page size aligned address and this could cause major
2888 - CONFIG_SYS_LOADS_BAUD_CHANGE:
2889 Enable temporary baudrate change while serial download
2891 - CONFIG_SYS_SDRAM_BASE:
2892 Physical start address of SDRAM. _Must_ be 0 here.
2894 - CONFIG_SYS_FLASH_BASE:
2895 Physical start address of Flash memory.
2897 - CONFIG_SYS_MONITOR_BASE:
2898 Physical start address of boot monitor code (set by
2899 make config files to be same as the text base address
2900 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
2901 CONFIG_SYS_FLASH_BASE when booting from flash.
2903 - CONFIG_SYS_MONITOR_LEN:
2904 Size of memory reserved for monitor code, used to
2905 determine _at_compile_time_ (!) if the environment is
2906 embedded within the U-Boot image, or in a separate
2909 - CONFIG_SYS_MALLOC_LEN:
2910 Size of DRAM reserved for malloc() use.
2912 - CONFIG_SYS_MALLOC_F_LEN
2913 Size of the malloc() pool for use before relocation. If
2914 this is defined, then a very simple malloc() implementation
2915 will become available before relocation. The address is just
2916 below the global data, and the stack is moved down to make
2919 This feature allocates regions with increasing addresses
2920 within the region. calloc() is supported, but realloc()
2921 is not available. free() is supported but does nothing.
2922 The memory will be freed (or in fact just forgotten) when
2923 U-Boot relocates itself.
2925 - CONFIG_SYS_MALLOC_SIMPLE
2926 Provides a simple and small malloc() and calloc() for those
2927 boards which do not use the full malloc in SPL (which is
2928 enabled with CONFIG_SYS_SPL_MALLOC_START).
2930 - CONFIG_SYS_NONCACHED_MEMORY:
2931 Size of non-cached memory area. This area of memory will be
2932 typically located right below the malloc() area and mapped
2933 uncached in the MMU. This is useful for drivers that would
2934 otherwise require a lot of explicit cache maintenance. For
2935 some drivers it's also impossible to properly maintain the
2936 cache. For example if the regions that need to be flushed
2937 are not a multiple of the cache-line size, *and* padding
2938 cannot be allocated between the regions to align them (i.e.
2939 if the HW requires a contiguous array of regions, and the
2940 size of each region is not cache-aligned), then a flush of
2941 one region may result in overwriting data that hardware has
2942 written to another region in the same cache-line. This can
2943 happen for example in network drivers where descriptors for
2944 buffers are typically smaller than the CPU cache-line (e.g.
2945 16 bytes vs. 32 or 64 bytes).
2947 Non-cached memory is only supported on 32-bit ARM at present.
2949 - CONFIG_SYS_BOOTM_LEN:
2950 Normally compressed uImages are limited to an
2951 uncompressed size of 8 MBytes. If this is not enough,
2952 you can define CONFIG_SYS_BOOTM_LEN in your board config file
2953 to adjust this setting to your needs.
2955 - CONFIG_SYS_BOOTMAPSZ:
2956 Maximum size of memory mapped by the startup code of
2957 the Linux kernel; all data that must be processed by
2958 the Linux kernel (bd_info, boot arguments, FDT blob if
2959 used) must be put below this limit, unless "bootm_low"
2960 environment variable is defined and non-zero. In such case
2961 all data for the Linux kernel must be between "bootm_low"
2962 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
2963 variable "bootm_mapsize" will override the value of
2964 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
2965 then the value in "bootm_size" will be used instead.
2967 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
2968 Enable initrd_high functionality. If defined then the
2969 initrd_high feature is enabled and the bootm ramdisk subcommand
2972 - CONFIG_SYS_BOOT_GET_CMDLINE:
2973 Enables allocating and saving kernel cmdline in space between
2974 "bootm_low" and "bootm_low" + BOOTMAPSZ.
2976 - CONFIG_SYS_BOOT_GET_KBD:
2977 Enables allocating and saving a kernel copy of the bd_info in
2978 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
2980 - CONFIG_SYS_MAX_FLASH_BANKS:
2981 Max number of Flash memory banks
2983 - CONFIG_SYS_MAX_FLASH_SECT:
2984 Max number of sectors on a Flash chip
2986 - CONFIG_SYS_FLASH_ERASE_TOUT:
2987 Timeout for Flash erase operations (in ms)
2989 - CONFIG_SYS_FLASH_WRITE_TOUT:
2990 Timeout for Flash write operations (in ms)
2992 - CONFIG_SYS_FLASH_LOCK_TOUT
2993 Timeout for Flash set sector lock bit operation (in ms)
2995 - CONFIG_SYS_FLASH_UNLOCK_TOUT
2996 Timeout for Flash clear lock bits operation (in ms)
2998 - CONFIG_SYS_FLASH_PROTECTION
2999 If defined, hardware flash sectors protection is used
3000 instead of U-Boot software protection.
3002 - CONFIG_SYS_DIRECT_FLASH_TFTP:
3004 Enable TFTP transfers directly to flash memory;
3005 without this option such a download has to be
3006 performed in two steps: (1) download to RAM, and (2)
3007 copy from RAM to flash.
3009 The two-step approach is usually more reliable, since
3010 you can check if the download worked before you erase
3011 the flash, but in some situations (when system RAM is
3012 too limited to allow for a temporary copy of the
3013 downloaded image) this option may be very useful.
3015 - CONFIG_SYS_FLASH_CFI:
3016 Define if the flash driver uses extra elements in the
3017 common flash structure for storing flash geometry.
3019 - CONFIG_FLASH_CFI_DRIVER
3020 This option also enables the building of the cfi_flash driver
3021 in the drivers directory
3023 - CONFIG_FLASH_CFI_MTD
3024 This option enables the building of the cfi_mtd driver
3025 in the drivers directory. The driver exports CFI flash
3028 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
3029 Use buffered writes to flash.
3031 - CONFIG_FLASH_SPANSION_S29WS_N
3032 s29ws-n MirrorBit flash has non-standard addresses for buffered
3035 - CONFIG_SYS_FLASH_QUIET_TEST
3036 If this option is defined, the common CFI flash doesn't
3037 print it's warning upon not recognized FLASH banks. This
3038 is useful, if some of the configured banks are only
3039 optionally available.
3041 - CONFIG_FLASH_SHOW_PROGRESS
3042 If defined (must be an integer), print out countdown
3043 digits and dots. Recommended value: 45 (9..1) for 80
3044 column displays, 15 (3..1) for 40 column displays.
3046 - CONFIG_FLASH_VERIFY
3047 If defined, the content of the flash (destination) is compared
3048 against the source after the write operation. An error message
3049 will be printed when the contents are not identical.
3050 Please note that this option is useless in nearly all cases,
3051 since such flash programming errors usually are detected earlier
3052 while unprotecting/erasing/programming. Please only enable
3053 this option if you really know what you are doing.
3055 - CONFIG_SYS_RX_ETH_BUFFER:
3056 Defines the number of Ethernet receive buffers. On some
3057 Ethernet controllers it is recommended to set this value
3058 to 8 or even higher (EEPRO100 or 405 EMAC), since all
3059 buffers can be full shortly after enabling the interface
3060 on high Ethernet traffic.
3061 Defaults to 4 if not defined.
3063 - CONFIG_ENV_MAX_ENTRIES
3065 Maximum number of entries in the hash table that is used
3066 internally to store the environment settings. The default
3067 setting is supposed to be generous and should work in most
3068 cases. This setting can be used to tune behaviour; see
3069 lib/hashtable.c for details.
3071 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3072 - CONFIG_ENV_FLAGS_LIST_STATIC
3073 Enable validation of the values given to environment variables when
3074 calling env set. Variables can be restricted to only decimal,
3075 hexadecimal, or boolean. If CONFIG_CMD_NET is also defined,
3076 the variables can also be restricted to IP address or MAC address.
3078 The format of the list is:
3079 type_attribute = [s|d|x|b|i|m]
3080 access_attribute = [a|r|o|c]
3081 attributes = type_attribute[access_attribute]
3082 entry = variable_name[:attributes]
3085 The type attributes are:
3086 s - String (default)
3089 b - Boolean ([1yYtT|0nNfF])
3093 The access attributes are:
3099 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3100 Define this to a list (string) to define the ".flags"
3101 environment variable in the default or embedded environment.
3103 - CONFIG_ENV_FLAGS_LIST_STATIC
3104 Define this to a list (string) to define validation that
3105 should be done if an entry is not found in the ".flags"
3106 environment variable. To override a setting in the static
3107 list, simply add an entry for the same variable name to the
3110 If CONFIG_REGEX is defined, the variable_name above is evaluated as a
3111 regular expression. This allows multiple variables to define the same
3112 flags without explicitly listing them for each variable.
3114 - CONFIG_ENV_ACCESS_IGNORE_FORCE
3115 If defined, don't allow the -f switch to env set override variable
3119 If stdint.h is available with your toolchain you can define this
3120 option to enable it. You can provide option 'USE_STDINT=1' when
3121 building U-Boot to enable this.
3123 The following definitions that deal with the placement and management
3124 of environment data (variable area); in general, we support the
3125 following configurations:
3127 - CONFIG_BUILD_ENVCRC:
3129 Builds up envcrc with the target environment so that external utils
3130 may easily extract it and embed it in final U-Boot images.
3132 BE CAREFUL! The first access to the environment happens quite early
3133 in U-Boot initialization (when we try to get the setting of for the
3134 console baudrate). You *MUST* have mapped your NVRAM area then, or
3137 Please note that even with NVRAM we still use a copy of the
3138 environment in RAM: we could work on NVRAM directly, but we want to
3139 keep settings there always unmodified except somebody uses "saveenv"
3140 to save the current settings.
3142 BE CAREFUL! For some special cases, the local device can not use
3143 "saveenv" command. For example, the local device will get the
3144 environment stored in a remote NOR flash by SRIO or PCIE link,
3145 but it can not erase, write this NOR flash by SRIO or PCIE interface.
3147 - CONFIG_NAND_ENV_DST
3149 Defines address in RAM to which the nand_spl code should copy the
3150 environment. If redundant environment is used, it will be copied to
3151 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
3153 Please note that the environment is read-only until the monitor
3154 has been relocated to RAM and a RAM copy of the environment has been
3155 created; also, when using EEPROM you will have to use env_get_f()
3156 until then to read environment variables.
3158 The environment is protected by a CRC32 checksum. Before the monitor
3159 is relocated into RAM, as a result of a bad CRC you will be working
3160 with the compiled-in default environment - *silently*!!! [This is
3161 necessary, because the first environment variable we need is the
3162 "baudrate" setting for the console - if we have a bad CRC, we don't
3163 have any device yet where we could complain.]
3165 Note: once the monitor has been relocated, then it will complain if
3166 the default environment is used; a new CRC is computed as soon as you
3167 use the "saveenv" command to store a valid environment.
3169 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
3170 Echo the inverted Ethernet link state to the fault LED.
3172 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
3173 also needs to be defined.
3175 - CONFIG_SYS_FAULT_MII_ADDR:
3176 MII address of the PHY to check for the Ethernet link state.
3178 - CONFIG_NS16550_MIN_FUNCTIONS:
3179 Define this if you desire to only have use of the NS16550_init
3180 and NS16550_putc functions for the serial driver located at
3181 drivers/serial/ns16550.c. This option is useful for saving
3182 space for already greatly restricted images, including but not
3183 limited to NAND_SPL configurations.
3185 - CONFIG_DISPLAY_BOARDINFO
3186 Display information about the board that U-Boot is running on
3187 when U-Boot starts up. The board function checkboard() is called
3190 - CONFIG_DISPLAY_BOARDINFO_LATE
3191 Similar to the previous option, but display this information
3192 later, once stdio is running and output goes to the LCD, if
3195 - CONFIG_BOARD_SIZE_LIMIT:
3196 Maximum size of the U-Boot image. When defined, the
3197 build system checks that the actual size does not
3200 Low Level (hardware related) configuration options:
3201 ---------------------------------------------------
3203 - CONFIG_SYS_CACHELINE_SIZE:
3204 Cache Line Size of the CPU.
3206 - CONFIG_SYS_CCSRBAR_DEFAULT:
3207 Default (power-on reset) physical address of CCSR on Freescale
3210 - CONFIG_SYS_CCSRBAR:
3211 Virtual address of CCSR. On a 32-bit build, this is typically
3212 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
3214 - CONFIG_SYS_CCSRBAR_PHYS:
3215 Physical address of CCSR. CCSR can be relocated to a new
3216 physical address, if desired. In this case, this macro should
3217 be set to that address. Otherwise, it should be set to the
3218 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
3219 is typically relocated on 36-bit builds. It is recommended
3220 that this macro be defined via the _HIGH and _LOW macros:
3222 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
3223 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
3225 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
3226 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
3227 either 0 (32-bit build) or 0xF (36-bit build). This macro is
3228 used in assembly code, so it must not contain typecasts or
3229 integer size suffixes (e.g. "ULL").
3231 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
3232 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
3233 used in assembly code, so it must not contain typecasts or
3234 integer size suffixes (e.g. "ULL").
3236 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
3237 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
3238 forced to a value that ensures that CCSR is not relocated.
3240 - Floppy Disk Support:
3241 CONFIG_SYS_FDC_DRIVE_NUMBER
3243 the default drive number (default value 0)
3245 CONFIG_SYS_ISA_IO_STRIDE
3247 defines the spacing between FDC chipset registers
3250 CONFIG_SYS_ISA_IO_OFFSET
3252 defines the offset of register from address. It
3253 depends on which part of the data bus is connected to
3254 the FDC chipset. (default value 0)
3256 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
3257 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
3260 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
3261 fdc_hw_init() is called at the beginning of the FDC
3262 setup. fdc_hw_init() must be provided by the board
3263 source code. It is used to make hardware-dependent
3267 Most IDE controllers were designed to be connected with PCI
3268 interface. Only few of them were designed for AHB interface.
3269 When software is doing ATA command and data transfer to
3270 IDE devices through IDE-AHB controller, some additional
3271 registers accessing to these kind of IDE-AHB controller
3274 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
3275 DO NOT CHANGE unless you know exactly what you're
3276 doing! (11-4) [MPC8xx systems only]
3278 - CONFIG_SYS_INIT_RAM_ADDR:
3280 Start address of memory area that can be used for
3281 initial data and stack; please note that this must be
3282 writable memory that is working WITHOUT special
3283 initialization, i. e. you CANNOT use normal RAM which
3284 will become available only after programming the
3285 memory controller and running certain initialization
3288 U-Boot uses the following memory types:
3289 - MPC8xx: IMMR (internal memory of the CPU)
3291 - CONFIG_SYS_GBL_DATA_OFFSET:
3293 Offset of the initial data structure in the memory
3294 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
3295 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
3296 data is located at the end of the available space
3297 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
3298 GENERATED_GBL_DATA_SIZE), and the initial stack is just
3299 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
3300 CONFIG_SYS_GBL_DATA_OFFSET) downward.
3303 On the MPC824X (or other systems that use the data
3304 cache for initial memory) the address chosen for
3305 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
3306 point to an otherwise UNUSED address space between
3307 the top of RAM and the start of the PCI space.
3309 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
3311 - CONFIG_SYS_OR_TIMING_SDRAM:
3314 - CONFIG_SYS_MAMR_PTA:
3315 periodic timer for refresh
3317 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
3318 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
3319 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
3320 CONFIG_SYS_BR1_PRELIM:
3321 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
3323 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
3324 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
3325 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
3326 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
3328 - CONFIG_PCI_ENUM_ONLY
3329 Only scan through and get the devices on the buses.
3330 Don't do any setup work, presumably because someone or
3331 something has already done it, and we don't need to do it
3332 a second time. Useful for platforms that are pre-booted
3333 by coreboot or similar.
3335 - CONFIG_PCI_INDIRECT_BRIDGE:
3336 Enable support for indirect PCI bridges.
3339 Chip has SRIO or not
3342 Board has SRIO 1 port available
3345 Board has SRIO 2 port available
3347 - CONFIG_SRIO_PCIE_BOOT_MASTER
3348 Board can support master function for Boot from SRIO and PCIE
3350 - CONFIG_SYS_SRIOn_MEM_VIRT:
3351 Virtual Address of SRIO port 'n' memory region
3353 - CONFIG_SYS_SRIOn_MEM_PHYS:
3354 Physical Address of SRIO port 'n' memory region
3356 - CONFIG_SYS_SRIOn_MEM_SIZE:
3357 Size of SRIO port 'n' memory region
3359 - CONFIG_SYS_NAND_BUSWIDTH_16BIT
3360 Defined to tell the NAND controller that the NAND chip is using
3362 Not all NAND drivers use this symbol.
3363 Example of drivers that use it:
3364 - drivers/mtd/nand/ndfc.c
3365 - drivers/mtd/nand/mxc_nand.c
3367 - CONFIG_SYS_NDFC_EBC0_CFG
3368 Sets the EBC0_CFG register for the NDFC. If not defined
3369 a default value will be used.
3372 Get DDR timing information from an I2C EEPROM. Common
3373 with pluggable memory modules such as SODIMMs
3376 I2C address of the SPD EEPROM
3378 - CONFIG_SYS_SPD_BUS_NUM
3379 If SPD EEPROM is on an I2C bus other than the first
3380 one, specify here. Note that the value must resolve
3381 to something your driver can deal with.
3383 - CONFIG_SYS_DDR_RAW_TIMING
3384 Get DDR timing information from other than SPD. Common with
3385 soldered DDR chips onboard without SPD. DDR raw timing
3386 parameters are extracted from datasheet and hard-coded into
3387 header files or board specific files.
3389 - CONFIG_FSL_DDR_INTERACTIVE
3390 Enable interactive DDR debugging. See doc/README.fsl-ddr.
3392 - CONFIG_FSL_DDR_SYNC_REFRESH
3393 Enable sync of refresh for multiple controllers.
3395 - CONFIG_FSL_DDR_BIST
3396 Enable built-in memory test for Freescale DDR controllers.
3398 - CONFIG_SYS_83XX_DDR_USES_CS0
3399 Only for 83xx systems. If specified, then DDR should
3400 be configured using CS0 and CS1 instead of CS2 and CS3.
3403 Enable RMII mode for all FECs.
3404 Note that this is a global option, we can't
3405 have one FEC in standard MII mode and another in RMII mode.
3407 - CONFIG_CRC32_VERIFY
3408 Add a verify option to the crc32 command.
3411 => crc32 -v <address> <count> <crc32>
3413 Where address/count indicate a memory area
3414 and crc32 is the correct crc32 which the
3418 Add the "loopw" memory command. This only takes effect if
3419 the memory commands are activated globally (CONFIG_CMD_MEMORY).
3422 Add the "mdc" and "mwc" memory commands. These are cyclic
3427 This command will print 4 bytes (10,11,12,13) each 500 ms.
3429 => mwc.l 100 12345678 10
3430 This command will write 12345678 to address 100 all 10 ms.
3432 This only takes effect if the memory commands are activated
3433 globally (CONFIG_CMD_MEMORY).
3435 - CONFIG_SKIP_LOWLEVEL_INIT
3436 [ARM, NDS32, MIPS, RISC-V only] If this variable is defined, then certain
3437 low level initializations (like setting up the memory
3438 controller) are omitted and/or U-Boot does not
3439 relocate itself into RAM.
3441 Normally this variable MUST NOT be defined. The only
3442 exception is when U-Boot is loaded (to RAM) by some
3443 other boot loader or by a debugger which performs
3444 these initializations itself.
3446 - CONFIG_SKIP_LOWLEVEL_INIT_ONLY
3447 [ARM926EJ-S only] This allows just the call to lowlevel_init()
3448 to be skipped. The normal CP15 init (such as enabling the
3449 instruction cache) is still performed.
3452 Modifies the behaviour of start.S when compiling a loader
3453 that is executed before the actual U-Boot. E.g. when
3454 compiling a NAND SPL.
3457 Modifies the behaviour of start.S when compiling a loader
3458 that is executed after the SPL and before the actual U-Boot.
3459 It is loaded by the SPL.
3461 - CONFIG_SYS_MPC85XX_NO_RESETVEC
3462 Only for 85xx systems. If this variable is specified, the section
3463 .resetvec is not kept and the section .bootpg is placed in the
3464 previous 4k of the .text section.
3466 - CONFIG_ARCH_MAP_SYSMEM
3467 Generally U-Boot (and in particular the md command) uses
3468 effective address. It is therefore not necessary to regard
3469 U-Boot address as virtual addresses that need to be translated
3470 to physical addresses. However, sandbox requires this, since
3471 it maintains its own little RAM buffer which contains all
3472 addressable memory. This option causes some memory accesses
3473 to be mapped through map_sysmem() / unmap_sysmem().
3475 - CONFIG_X86_RESET_VECTOR
3476 If defined, the x86 reset vector code is included. This is not
3477 needed when U-Boot is running from Coreboot.
3479 - CONFIG_SPL_AM33XX_ENABLE_RTC32K_OSC:
3480 Enables the RTC32K OSC on AM33xx based plattforms
3482 - CONFIG_SYS_NAND_NO_SUBPAGE_WRITE
3483 Option to disable subpage write in NAND driver
3484 driver that uses this:
3485 drivers/mtd/nand/davinci_nand.c
3487 Freescale QE/FMAN Firmware Support:
3488 -----------------------------------
3490 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
3491 loading of "firmware", which is encoded in the QE firmware binary format.
3492 This firmware often needs to be loaded during U-Boot booting, so macros
3493 are used to identify the storage device (NOR flash, SPI, etc) and the address
3496 - CONFIG_SYS_FMAN_FW_ADDR
3497 The address in the storage device where the FMAN microcode is located. The
3498 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
3501 - CONFIG_SYS_QE_FW_ADDR
3502 The address in the storage device where the QE microcode is located. The
3503 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
3506 - CONFIG_SYS_QE_FMAN_FW_LENGTH
3507 The maximum possible size of the firmware. The firmware binary format
3508 has a field that specifies the actual size of the firmware, but it
3509 might not be possible to read any part of the firmware unless some
3510 local storage is allocated to hold the entire firmware first.
3512 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
3513 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
3514 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
3515 virtual address in NOR flash.
3517 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
3518 Specifies that QE/FMAN firmware is located in NAND flash.
3519 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
3521 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
3522 Specifies that QE/FMAN firmware is located on the primary SD/MMC
3523 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
3525 - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
3526 Specifies that QE/FMAN firmware is located in the remote (master)
3527 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
3528 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
3529 window->master inbound window->master LAW->the ucode address in
3530 master's memory space.
3532 Freescale Layerscape Management Complex Firmware Support:
3533 ---------------------------------------------------------
3534 The Freescale Layerscape Management Complex (MC) supports the loading of
3536 This firmware often needs to be loaded during U-Boot booting, so macros
3537 are used to identify the storage device (NOR flash, SPI, etc) and the address
3540 - CONFIG_FSL_MC_ENET
3541 Enable the MC driver for Layerscape SoCs.
3543 Freescale Layerscape Debug Server Support:
3544 -------------------------------------------
3545 The Freescale Layerscape Debug Server Support supports the loading of
3546 "Debug Server firmware" and triggering SP boot-rom.
3547 This firmware often needs to be loaded during U-Boot booting.
3549 - CONFIG_SYS_MC_RSV_MEM_ALIGN
3550 Define alignment of reserved memory MC requires
3555 In order to achieve reproducible builds, timestamps used in the U-Boot build
3556 process have to be set to a fixed value.
3558 This is done using the SOURCE_DATE_EPOCH environment variable.
3559 SOURCE_DATE_EPOCH is to be set on the build host's shell, not as a configuration
3560 option for U-Boot or an environment variable in U-Boot.
3562 SOURCE_DATE_EPOCH should be set to a number of seconds since the epoch, in UTC.
3564 Building the Software:
3565 ======================
3567 Building U-Boot has been tested in several native build environments
3568 and in many different cross environments. Of course we cannot support
3569 all possibly existing versions of cross development tools in all
3570 (potentially obsolete) versions. In case of tool chain problems we
3571 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
3572 which is extensively used to build and test U-Boot.
3574 If you are not using a native environment, it is assumed that you
3575 have GNU cross compiling tools available in your path. In this case,
3576 you must set the environment variable CROSS_COMPILE in your shell.
3577 Note that no changes to the Makefile or any other source files are
3578 necessary. For example using the ELDK on a 4xx CPU, please enter:
3580 $ CROSS_COMPILE=ppc_4xx-
3581 $ export CROSS_COMPILE
3583 Note: If you wish to generate Windows versions of the utilities in
3584 the tools directory you can use the MinGW toolchain
3585 (http://www.mingw.org). Set your HOST tools to the MinGW
3586 toolchain and execute 'make tools'. For example:
3588 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
3590 Binaries such as tools/mkimage.exe will be created which can
3591 be executed on computers running Windows.
3593 U-Boot is intended to be simple to build. After installing the
3594 sources you must configure U-Boot for one specific board type. This
3599 where "NAME_defconfig" is the name of one of the existing configu-
3600 rations; see boards.cfg for supported names.
3602 Note: for some board special configuration names may exist; check if
3603 additional information is available from the board vendor; for
3604 instance, the TQM823L systems are available without (standard)
3605 or with LCD support. You can select such additional "features"
3606 when choosing the configuration, i. e.
3608 make TQM823L_defconfig
3609 - will configure for a plain TQM823L, i. e. no LCD support
3611 make TQM823L_LCD_defconfig
3612 - will configure for a TQM823L with U-Boot console on LCD
3617 Finally, type "make all", and you should get some working U-Boot
3618 images ready for download to / installation on your system:
3620 - "u-boot.bin" is a raw binary image
3621 - "u-boot" is an image in ELF binary format
3622 - "u-boot.srec" is in Motorola S-Record format
3624 By default the build is performed locally and the objects are saved
3625 in the source directory. One of the two methods can be used to change
3626 this behavior and build U-Boot to some external directory:
3628 1. Add O= to the make command line invocations:
3630 make O=/tmp/build distclean
3631 make O=/tmp/build NAME_defconfig
3632 make O=/tmp/build all
3634 2. Set environment variable KBUILD_OUTPUT to point to the desired location:
3636 export KBUILD_OUTPUT=/tmp/build
3641 Note that the command line "O=" setting overrides the KBUILD_OUTPUT environment
3644 User specific CPPFLAGS, AFLAGS and CFLAGS can be passed to the compiler by
3645 setting the according environment variables KCPPFLAGS, KAFLAGS and KCFLAGS.
3646 For example to treat all compiler warnings as errors:
3648 make KCFLAGS=-Werror
3650 Please be aware that the Makefiles assume you are using GNU make, so
3651 for instance on NetBSD you might need to use "gmake" instead of
3655 If the system board that you have is not listed, then you will need
3656 to port U-Boot to your hardware platform. To do this, follow these
3659 1. Create a new directory to hold your board specific code. Add any
3660 files you need. In your board directory, you will need at least
3661 the "Makefile" and a "<board>.c".
3662 2. Create a new configuration file "include/configs/<board>.h" for
3664 3. If you're porting U-Boot to a new CPU, then also create a new
3665 directory to hold your CPU specific code. Add any files you need.
3666 4. Run "make <board>_defconfig" with your new name.
3667 5. Type "make", and you should get a working "u-boot.srec" file
3668 to be installed on your target system.
3669 6. Debug and solve any problems that might arise.
3670 [Of course, this last step is much harder than it sounds.]
3673 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
3674 ==============================================================
3676 If you have modified U-Boot sources (for instance added a new board
3677 or support for new devices, a new CPU, etc.) you are expected to
3678 provide feedback to the other developers. The feedback normally takes
3679 the form of a "patch", i. e. a context diff against a certain (latest
3680 official or latest in the git repository) version of U-Boot sources.
3682 But before you submit such a patch, please verify that your modifi-
3683 cation did not break existing code. At least make sure that *ALL* of
3684 the supported boards compile WITHOUT ANY compiler warnings. To do so,
3685 just run the buildman script (tools/buildman/buildman), which will
3686 configure and build U-Boot for ALL supported system. Be warned, this
3687 will take a while. Please see the buildman README, or run 'buildman -H'
3691 See also "U-Boot Porting Guide" below.
3694 Monitor Commands - Overview:
3695 ============================
3697 go - start application at address 'addr'
3698 run - run commands in an environment variable
3699 bootm - boot application image from memory
3700 bootp - boot image via network using BootP/TFTP protocol
3701 bootz - boot zImage from memory
3702 tftpboot- boot image via network using TFTP protocol
3703 and env variables "ipaddr" and "serverip"
3704 (and eventually "gatewayip")
3705 tftpput - upload a file via network using TFTP protocol
3706 rarpboot- boot image via network using RARP/TFTP protocol
3707 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
3708 loads - load S-Record file over serial line
3709 loadb - load binary file over serial line (kermit mode)
3711 mm - memory modify (auto-incrementing)
3712 nm - memory modify (constant address)
3713 mw - memory write (fill)
3715 cmp - memory compare
3716 crc32 - checksum calculation
3717 i2c - I2C sub-system
3718 sspi - SPI utility commands
3719 base - print or set address offset
3720 printenv- print environment variables
3721 setenv - set environment variables
3722 saveenv - save environment variables to persistent storage
3723 protect - enable or disable FLASH write protection
3724 erase - erase FLASH memory
3725 flinfo - print FLASH memory information
3726 nand - NAND memory operations (see doc/README.nand)
3727 bdinfo - print Board Info structure
3728 iminfo - print header information for application image
3729 coninfo - print console devices and informations
3730 ide - IDE sub-system
3731 loop - infinite loop on address range
3732 loopw - infinite write loop on address range
3733 mtest - simple RAM test
3734 icache - enable or disable instruction cache
3735 dcache - enable or disable data cache
3736 reset - Perform RESET of the CPU
3737 echo - echo args to console
3738 version - print monitor version
3739 help - print online help
3740 ? - alias for 'help'
3743 Monitor Commands - Detailed Description:
3744 ========================================
3748 For now: just type "help <command>".
3751 Environment Variables:
3752 ======================
3754 U-Boot supports user configuration using Environment Variables which
3755 can be made persistent by saving to Flash memory.
3757 Environment Variables are set using "setenv", printed using
3758 "printenv", and saved to Flash using "saveenv". Using "setenv"
3759 without a value can be used to delete a variable from the
3760 environment. As long as you don't save the environment you are
3761 working with an in-memory copy. In case the Flash area containing the
3762 environment is erased by accident, a default environment is provided.
3764 Some configuration options can be set using Environment Variables.
3766 List of environment variables (most likely not complete):
3768 baudrate - see CONFIG_BAUDRATE
3770 bootdelay - see CONFIG_BOOTDELAY
3772 bootcmd - see CONFIG_BOOTCOMMAND
3774 bootargs - Boot arguments when booting an RTOS image
3776 bootfile - Name of the image to load with TFTP
3778 bootm_low - Memory range available for image processing in the bootm
3779 command can be restricted. This variable is given as
3780 a hexadecimal number and defines lowest address allowed
3781 for use by the bootm command. See also "bootm_size"
3782 environment variable. Address defined by "bootm_low" is
3783 also the base of the initial memory mapping for the Linux
3784 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
3787 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
3788 This variable is given as a hexadecimal number and it
3789 defines the size of the memory region starting at base
3790 address bootm_low that is accessible by the Linux kernel
3791 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
3792 as the default value if it is defined, and bootm_size is
3795 bootm_size - Memory range available for image processing in the bootm
3796 command can be restricted. This variable is given as
3797 a hexadecimal number and defines the size of the region
3798 allowed for use by the bootm command. See also "bootm_low"
3799 environment variable.
3801 updatefile - Location of the software update file on a TFTP server, used
3802 by the automatic software update feature. Please refer to
3803 documentation in doc/README.update for more details.
3805 autoload - if set to "no" (any string beginning with 'n'),
3806 "bootp" will just load perform a lookup of the
3807 configuration from the BOOTP server, but not try to
3808 load any image using TFTP
3810 autostart - if set to "yes", an image loaded using the "bootp",
3811 "rarpboot", "tftpboot" or "diskboot" commands will
3812 be automatically started (by internally calling
3815 If set to "no", a standalone image passed to the
3816 "bootm" command will be copied to the load address
3817 (and eventually uncompressed), but NOT be started.
3818 This can be used to load and uncompress arbitrary
3821 fdt_high - if set this restricts the maximum address that the
3822 flattened device tree will be copied into upon boot.
3823 For example, if you have a system with 1 GB memory
3824 at physical address 0x10000000, while Linux kernel
3825 only recognizes the first 704 MB as low memory, you
3826 may need to set fdt_high as 0x3C000000 to have the
3827 device tree blob be copied to the maximum address
3828 of the 704 MB low memory, so that Linux kernel can
3829 access it during the boot procedure.
3831 If this is set to the special value 0xFFFFFFFF then
3832 the fdt will not be copied at all on boot. For this
3833 to work it must reside in writable memory, have
3834 sufficient padding on the end of it for u-boot to
3835 add the information it needs into it, and the memory
3836 must be accessible by the kernel.
3838 fdtcontroladdr- if set this is the address of the control flattened
3839 device tree used by U-Boot when CONFIG_OF_CONTROL is
3842 i2cfast - (PPC405GP|PPC405EP only)
3843 if set to 'y' configures Linux I2C driver for fast
3844 mode (400kHZ). This environment variable is used in
3845 initialization code. So, for changes to be effective
3846 it must be saved and board must be reset.
3848 initrd_high - restrict positioning of initrd images:
3849 If this variable is not set, initrd images will be
3850 copied to the highest possible address in RAM; this
3851 is usually what you want since it allows for
3852 maximum initrd size. If for some reason you want to
3853 make sure that the initrd image is loaded below the
3854 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
3855 variable to a value of "no" or "off" or "0".
3856 Alternatively, you can set it to a maximum upper
3857 address to use (U-Boot will still check that it
3858 does not overwrite the U-Boot stack and data).
3860 For instance, when you have a system with 16 MB
3861 RAM, and want to reserve 4 MB from use by Linux,
3862 you can do this by adding "mem=12M" to the value of
3863 the "bootargs" variable. However, now you must make
3864 sure that the initrd image is placed in the first
3865 12 MB as well - this can be done with
3867 setenv initrd_high 00c00000
3869 If you set initrd_high to 0xFFFFFFFF, this is an
3870 indication to U-Boot that all addresses are legal
3871 for the Linux kernel, including addresses in flash
3872 memory. In this case U-Boot will NOT COPY the
3873 ramdisk at all. This may be useful to reduce the
3874 boot time on your system, but requires that this
3875 feature is supported by your Linux kernel.
3877 ipaddr - IP address; needed for tftpboot command
3879 loadaddr - Default load address for commands like "bootp",
3880 "rarpboot", "tftpboot", "loadb" or "diskboot"
3882 loads_echo - see CONFIG_LOADS_ECHO
3884 serverip - TFTP server IP address; needed for tftpboot command
3886 bootretry - see CONFIG_BOOT_RETRY_TIME
3888 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
3890 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
3892 ethprime - controls which interface is used first.
3894 ethact - controls which interface is currently active.
3895 For example you can do the following
3897 => setenv ethact FEC
3898 => ping 192.168.0.1 # traffic sent on FEC
3899 => setenv ethact SCC
3900 => ping 10.0.0.1 # traffic sent on SCC
3902 ethrotate - When set to "no" U-Boot does not go through all
3903 available network interfaces.
3904 It just stays at the currently selected interface.
3906 netretry - When set to "no" each network operation will
3907 either succeed or fail without retrying.
3908 When set to "once" the network operation will
3909 fail when all the available network interfaces
3910 are tried once without success.
3911 Useful on scripts which control the retry operation
3914 npe_ucode - set load address for the NPE microcode
3916 silent_linux - If set then Linux will be told to boot silently, by
3917 changing the console to be empty. If "yes" it will be
3918 made silent. If "no" it will not be made silent. If
3919 unset, then it will be made silent if the U-Boot console
3922 tftpsrcp - If this is set, the value is used for TFTP's
3925 tftpdstp - If this is set, the value is used for TFTP's UDP
3926 destination port instead of the Well Know Port 69.
3928 tftpblocksize - Block size to use for TFTP transfers; if not set,
3929 we use the TFTP server's default block size
3931 tftptimeout - Retransmission timeout for TFTP packets (in milli-
3932 seconds, minimum value is 1000 = 1 second). Defines
3933 when a packet is considered to be lost so it has to
3934 be retransmitted. The default is 5000 = 5 seconds.
3935 Lowering this value may make downloads succeed
3936 faster in networks with high packet loss rates or
3937 with unreliable TFTP servers.
3939 tftptimeoutcountmax - maximum count of TFTP timeouts (no
3940 unit, minimum value = 0). Defines how many timeouts
3941 can happen during a single file transfer before that
3942 transfer is aborted. The default is 10, and 0 means
3943 'no timeouts allowed'. Increasing this value may help
3944 downloads succeed with high packet loss rates, or with
3945 unreliable TFTP servers or client hardware.
3947 vlan - When set to a value < 4095 the traffic over
3948 Ethernet is encapsulated/received over 802.1q
3951 bootpretryperiod - Period during which BOOTP/DHCP sends retries.
3952 Unsigned value, in milliseconds. If not set, the period will
3953 be either the default (28000), or a value based on
3954 CONFIG_NET_RETRY_COUNT, if defined. This value has
3955 precedence over the valu based on CONFIG_NET_RETRY_COUNT.
3957 The following image location variables contain the location of images
3958 used in booting. The "Image" column gives the role of the image and is
3959 not an environment variable name. The other columns are environment
3960 variable names. "File Name" gives the name of the file on a TFTP
3961 server, "RAM Address" gives the location in RAM the image will be
3962 loaded to, and "Flash Location" gives the image's address in NOR
3963 flash or offset in NAND flash.
3965 *Note* - these variables don't have to be defined for all boards, some
3966 boards currently use other variables for these purposes, and some
3967 boards use these variables for other purposes.
3969 Image File Name RAM Address Flash Location
3970 ----- --------- ----------- --------------
3971 u-boot u-boot u-boot_addr_r u-boot_addr
3972 Linux kernel bootfile kernel_addr_r kernel_addr
3973 device tree blob fdtfile fdt_addr_r fdt_addr
3974 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
3976 The following environment variables may be used and automatically
3977 updated by the network boot commands ("bootp" and "rarpboot"),
3978 depending the information provided by your boot server:
3980 bootfile - see above
3981 dnsip - IP address of your Domain Name Server
3982 dnsip2 - IP address of your secondary Domain Name Server
3983 gatewayip - IP address of the Gateway (Router) to use
3984 hostname - Target hostname
3986 netmask - Subnet Mask
3987 rootpath - Pathname of the root filesystem on the NFS server
3988 serverip - see above
3991 There are two special Environment Variables:
3993 serial# - contains hardware identification information such
3994 as type string and/or serial number
3995 ethaddr - Ethernet address
3997 These variables can be set only once (usually during manufacturing of
3998 the board). U-Boot refuses to delete or overwrite these variables
3999 once they have been set once.
4002 Further special Environment Variables:
4004 ver - Contains the U-Boot version string as printed
4005 with the "version" command. This variable is
4006 readonly (see CONFIG_VERSION_VARIABLE).
4009 Please note that changes to some configuration parameters may take
4010 only effect after the next boot (yes, that's just like Windoze :-).
4013 Callback functions for environment variables:
4014 ---------------------------------------------
4016 For some environment variables, the behavior of u-boot needs to change
4017 when their values are changed. This functionality allows functions to
4018 be associated with arbitrary variables. On creation, overwrite, or
4019 deletion, the callback will provide the opportunity for some side
4020 effect to happen or for the change to be rejected.
4022 The callbacks are named and associated with a function using the
4023 U_BOOT_ENV_CALLBACK macro in your board or driver code.
4025 These callbacks are associated with variables in one of two ways. The
4026 static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC
4027 in the board configuration to a string that defines a list of
4028 associations. The list must be in the following format:
4030 entry = variable_name[:callback_name]
4033 If the callback name is not specified, then the callback is deleted.
4034 Spaces are also allowed anywhere in the list.
4036 Callbacks can also be associated by defining the ".callbacks" variable
4037 with the same list format above. Any association in ".callbacks" will
4038 override any association in the static list. You can define
4039 CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the
4040 ".callbacks" environment variable in the default or embedded environment.
4042 If CONFIG_REGEX is defined, the variable_name above is evaluated as a
4043 regular expression. This allows multiple variables to be connected to
4044 the same callback without explicitly listing them all out.
4047 Command Line Parsing:
4048 =====================
4050 There are two different command line parsers available with U-Boot:
4051 the old "simple" one, and the much more powerful "hush" shell:
4053 Old, simple command line parser:
4054 --------------------------------
4056 - supports environment variables (through setenv / saveenv commands)
4057 - several commands on one line, separated by ';'
4058 - variable substitution using "... ${name} ..." syntax
4059 - special characters ('$', ';') can be escaped by prefixing with '\',
4061 setenv bootcmd bootm \${address}
4062 - You can also escape text by enclosing in single apostrophes, for example:
4063 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
4068 - similar to Bourne shell, with control structures like
4069 if...then...else...fi, for...do...done; while...do...done,
4070 until...do...done, ...
4071 - supports environment ("global") variables (through setenv / saveenv
4072 commands) and local shell variables (through standard shell syntax
4073 "name=value"); only environment variables can be used with "run"
4079 (1) If a command line (or an environment variable executed by a "run"
4080 command) contains several commands separated by semicolon, and
4081 one of these commands fails, then the remaining commands will be
4084 (2) If you execute several variables with one call to run (i. e.
4085 calling run with a list of variables as arguments), any failing
4086 command will cause "run" to terminate, i. e. the remaining
4087 variables are not executed.
4089 Note for Redundant Ethernet Interfaces:
4090 =======================================
4092 Some boards come with redundant Ethernet interfaces; U-Boot supports
4093 such configurations and is capable of automatic selection of a
4094 "working" interface when needed. MAC assignment works as follows:
4096 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
4097 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
4098 "eth1addr" (=>eth1), "eth2addr", ...
4100 If the network interface stores some valid MAC address (for instance
4101 in SROM), this is used as default address if there is NO correspon-
4102 ding setting in the environment; if the corresponding environment
4103 variable is set, this overrides the settings in the card; that means:
4105 o If the SROM has a valid MAC address, and there is no address in the
4106 environment, the SROM's address is used.
4108 o If there is no valid address in the SROM, and a definition in the
4109 environment exists, then the value from the environment variable is
4112 o If both the SROM and the environment contain a MAC address, and
4113 both addresses are the same, this MAC address is used.
4115 o If both the SROM and the environment contain a MAC address, and the
4116 addresses differ, the value from the environment is used and a
4119 o If neither SROM nor the environment contain a MAC address, an error
4120 is raised. If CONFIG_NET_RANDOM_ETHADDR is defined, then in this case
4121 a random, locally-assigned MAC is used.
4123 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
4124 will be programmed into hardware as part of the initialization process. This
4125 may be skipped by setting the appropriate 'ethmacskip' environment variable.
4126 The naming convention is as follows:
4127 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
4132 U-Boot is capable of booting (and performing other auxiliary operations on)
4133 images in two formats:
4135 New uImage format (FIT)
4136 -----------------------
4138 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
4139 to Flattened Device Tree). It allows the use of images with multiple
4140 components (several kernels, ramdisks, etc.), with contents protected by
4141 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
4147 Old image format is based on binary files which can be basically anything,
4148 preceded by a special header; see the definitions in include/image.h for
4149 details; basically, the header defines the following image properties:
4151 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
4152 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
4153 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
4154 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
4156 * Target CPU Architecture (Provisions for Alpha, ARM, Intel x86,
4157 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
4158 Currently supported: ARM, Intel x86, MIPS, NDS32, Nios II, PowerPC).
4159 * Compression Type (uncompressed, gzip, bzip2)
4165 The header is marked by a special Magic Number, and both the header
4166 and the data portions of the image are secured against corruption by
4173 Although U-Boot should support any OS or standalone application
4174 easily, the main focus has always been on Linux during the design of
4177 U-Boot includes many features that so far have been part of some
4178 special "boot loader" code within the Linux kernel. Also, any
4179 "initrd" images to be used are no longer part of one big Linux image;
4180 instead, kernel and "initrd" are separate images. This implementation
4181 serves several purposes:
4183 - the same features can be used for other OS or standalone
4184 applications (for instance: using compressed images to reduce the
4185 Flash memory footprint)
4187 - it becomes much easier to port new Linux kernel versions because
4188 lots of low-level, hardware dependent stuff are done by U-Boot
4190 - the same Linux kernel image can now be used with different "initrd"
4191 images; of course this also means that different kernel images can
4192 be run with the same "initrd". This makes testing easier (you don't
4193 have to build a new "zImage.initrd" Linux image when you just
4194 change a file in your "initrd"). Also, a field-upgrade of the
4195 software is easier now.
4201 Porting Linux to U-Boot based systems:
4202 ---------------------------------------
4204 U-Boot cannot save you from doing all the necessary modifications to
4205 configure the Linux device drivers for use with your target hardware
4206 (no, we don't intend to provide a full virtual machine interface to
4209 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
4211 Just make sure your machine specific header file (for instance
4212 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
4213 Information structure as we define in include/asm-<arch>/u-boot.h,
4214 and make sure that your definition of IMAP_ADDR uses the same value
4215 as your U-Boot configuration in CONFIG_SYS_IMMR.
4217 Note that U-Boot now has a driver model, a unified model for drivers.
4218 If you are adding a new driver, plumb it into driver model. If there
4219 is no uclass available, you are encouraged to create one. See
4223 Configuring the Linux kernel:
4224 -----------------------------
4226 No specific requirements for U-Boot. Make sure you have some root
4227 device (initial ramdisk, NFS) for your target system.
4230 Building a Linux Image:
4231 -----------------------
4233 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
4234 not used. If you use recent kernel source, a new build target
4235 "uImage" will exist which automatically builds an image usable by
4236 U-Boot. Most older kernels also have support for a "pImage" target,
4237 which was introduced for our predecessor project PPCBoot and uses a
4238 100% compatible format.
4242 make TQM850L_defconfig
4247 The "uImage" build target uses a special tool (in 'tools/mkimage') to
4248 encapsulate a compressed Linux kernel image with header information,
4249 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
4251 * build a standard "vmlinux" kernel image (in ELF binary format):
4253 * convert the kernel into a raw binary image:
4255 ${CROSS_COMPILE}-objcopy -O binary \
4256 -R .note -R .comment \
4257 -S vmlinux linux.bin
4259 * compress the binary image:
4263 * package compressed binary image for U-Boot:
4265 mkimage -A ppc -O linux -T kernel -C gzip \
4266 -a 0 -e 0 -n "Linux Kernel Image" \
4267 -d linux.bin.gz uImage
4270 The "mkimage" tool can also be used to create ramdisk images for use
4271 with U-Boot, either separated from the Linux kernel image, or
4272 combined into one file. "mkimage" encapsulates the images with a 64
4273 byte header containing information about target architecture,
4274 operating system, image type, compression method, entry points, time
4275 stamp, CRC32 checksums, etc.
4277 "mkimage" can be called in two ways: to verify existing images and
4278 print the header information, or to build new images.
4280 In the first form (with "-l" option) mkimage lists the information
4281 contained in the header of an existing U-Boot image; this includes
4282 checksum verification:
4284 tools/mkimage -l image
4285 -l ==> list image header information
4287 The second form (with "-d" option) is used to build a U-Boot image
4288 from a "data file" which is used as image payload:
4290 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
4291 -n name -d data_file image
4292 -A ==> set architecture to 'arch'
4293 -O ==> set operating system to 'os'
4294 -T ==> set image type to 'type'
4295 -C ==> set compression type 'comp'
4296 -a ==> set load address to 'addr' (hex)
4297 -e ==> set entry point to 'ep' (hex)
4298 -n ==> set image name to 'name'
4299 -d ==> use image data from 'datafile'
4301 Right now, all Linux kernels for PowerPC systems use the same load
4302 address (0x00000000), but the entry point address depends on the
4305 - 2.2.x kernels have the entry point at 0x0000000C,
4306 - 2.3.x and later kernels have the entry point at 0x00000000.
4308 So a typical call to build a U-Boot image would read:
4310 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
4311 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
4312 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
4313 > examples/uImage.TQM850L
4314 Image Name: 2.4.4 kernel for TQM850L
4315 Created: Wed Jul 19 02:34:59 2000
4316 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4317 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
4318 Load Address: 0x00000000
4319 Entry Point: 0x00000000
4321 To verify the contents of the image (or check for corruption):
4323 -> tools/mkimage -l examples/uImage.TQM850L
4324 Image Name: 2.4.4 kernel for TQM850L
4325 Created: Wed Jul 19 02:34:59 2000
4326 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4327 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
4328 Load Address: 0x00000000
4329 Entry Point: 0x00000000
4331 NOTE: for embedded systems where boot time is critical you can trade
4332 speed for memory and install an UNCOMPRESSED image instead: this
4333 needs more space in Flash, but boots much faster since it does not
4334 need to be uncompressed:
4336 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
4337 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
4338 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
4339 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
4340 > examples/uImage.TQM850L-uncompressed
4341 Image Name: 2.4.4 kernel for TQM850L
4342 Created: Wed Jul 19 02:34:59 2000
4343 Image Type: PowerPC Linux Kernel Image (uncompressed)
4344 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
4345 Load Address: 0x00000000
4346 Entry Point: 0x00000000
4349 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
4350 when your kernel is intended to use an initial ramdisk:
4352 -> tools/mkimage -n 'Simple Ramdisk Image' \
4353 > -A ppc -O linux -T ramdisk -C gzip \
4354 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
4355 Image Name: Simple Ramdisk Image
4356 Created: Wed Jan 12 14:01:50 2000
4357 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4358 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
4359 Load Address: 0x00000000
4360 Entry Point: 0x00000000
4362 The "dumpimage" is a tool to disassemble images built by mkimage. Its "-i"
4363 option performs the converse operation of the mkimage's second form (the "-d"
4364 option). Given an image built by mkimage, the dumpimage extracts a "data file"
4367 tools/dumpimage -i image -T type -p position data_file
4368 -i ==> extract from the 'image' a specific 'data_file'
4369 -T ==> set image type to 'type'
4370 -p ==> 'position' (starting at 0) of the 'data_file' inside the 'image'
4373 Installing a Linux Image:
4374 -------------------------
4376 To downloading a U-Boot image over the serial (console) interface,
4377 you must convert the image to S-Record format:
4379 objcopy -I binary -O srec examples/image examples/image.srec
4381 The 'objcopy' does not understand the information in the U-Boot
4382 image header, so the resulting S-Record file will be relative to
4383 address 0x00000000. To load it to a given address, you need to
4384 specify the target address as 'offset' parameter with the 'loads'
4387 Example: install the image to address 0x40100000 (which on the
4388 TQM8xxL is in the first Flash bank):
4390 => erase 40100000 401FFFFF
4396 ## Ready for S-Record download ...
4397 ~>examples/image.srec
4398 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
4400 15989 15990 15991 15992
4401 [file transfer complete]
4403 ## Start Addr = 0x00000000
4406 You can check the success of the download using the 'iminfo' command;
4407 this includes a checksum verification so you can be sure no data
4408 corruption happened:
4412 ## Checking Image at 40100000 ...
4413 Image Name: 2.2.13 for initrd on TQM850L
4414 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4415 Data Size: 335725 Bytes = 327 kB = 0 MB
4416 Load Address: 00000000
4417 Entry Point: 0000000c
4418 Verifying Checksum ... OK
4424 The "bootm" command is used to boot an application that is stored in
4425 memory (RAM or Flash). In case of a Linux kernel image, the contents
4426 of the "bootargs" environment variable is passed to the kernel as
4427 parameters. You can check and modify this variable using the
4428 "printenv" and "setenv" commands:
4431 => printenv bootargs
4432 bootargs=root=/dev/ram
4434 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4436 => printenv bootargs
4437 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4440 ## Booting Linux kernel at 40020000 ...
4441 Image Name: 2.2.13 for NFS on TQM850L
4442 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4443 Data Size: 381681 Bytes = 372 kB = 0 MB
4444 Load Address: 00000000
4445 Entry Point: 0000000c
4446 Verifying Checksum ... OK
4447 Uncompressing Kernel Image ... OK
4448 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
4449 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
4450 time_init: decrementer frequency = 187500000/60
4451 Calibrating delay loop... 49.77 BogoMIPS
4452 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
4455 If you want to boot a Linux kernel with initial RAM disk, you pass
4456 the memory addresses of both the kernel and the initrd image (PPBCOOT
4457 format!) to the "bootm" command:
4459 => imi 40100000 40200000
4461 ## Checking Image at 40100000 ...
4462 Image Name: 2.2.13 for initrd on TQM850L
4463 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4464 Data Size: 335725 Bytes = 327 kB = 0 MB
4465 Load Address: 00000000
4466 Entry Point: 0000000c
4467 Verifying Checksum ... OK
4469 ## Checking Image at 40200000 ...
4470 Image Name: Simple Ramdisk Image
4471 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4472 Data Size: 566530 Bytes = 553 kB = 0 MB
4473 Load Address: 00000000
4474 Entry Point: 00000000
4475 Verifying Checksum ... OK
4477 => bootm 40100000 40200000
4478 ## Booting Linux kernel at 40100000 ...
4479 Image Name: 2.2.13 for initrd on TQM850L
4480 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4481 Data Size: 335725 Bytes = 327 kB = 0 MB
4482 Load Address: 00000000
4483 Entry Point: 0000000c
4484 Verifying Checksum ... OK
4485 Uncompressing Kernel Image ... OK
4486 ## Loading RAMDisk Image at 40200000 ...
4487 Image Name: Simple Ramdisk Image
4488 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
4489 Data Size: 566530 Bytes = 553 kB = 0 MB
4490 Load Address: 00000000
4491 Entry Point: 00000000
4492 Verifying Checksum ... OK
4493 Loading Ramdisk ... OK
4494 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
4495 Boot arguments: root=/dev/ram
4496 time_init: decrementer frequency = 187500000/60
4497 Calibrating delay loop... 49.77 BogoMIPS
4499 RAMDISK: Compressed image found at block 0
4500 VFS: Mounted root (ext2 filesystem).
4504 Boot Linux and pass a flat device tree:
4507 First, U-Boot must be compiled with the appropriate defines. See the section
4508 titled "Linux Kernel Interface" above for a more in depth explanation. The
4509 following is an example of how to start a kernel and pass an updated
4515 oft=oftrees/mpc8540ads.dtb
4516 => tftp $oftaddr $oft
4517 Speed: 1000, full duplex
4519 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
4520 Filename 'oftrees/mpc8540ads.dtb'.
4521 Load address: 0x300000
4524 Bytes transferred = 4106 (100a hex)
4525 => tftp $loadaddr $bootfile
4526 Speed: 1000, full duplex
4528 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
4530 Load address: 0x200000
4531 Loading:############
4533 Bytes transferred = 1029407 (fb51f hex)
4538 => bootm $loadaddr - $oftaddr
4539 ## Booting image at 00200000 ...
4540 Image Name: Linux-2.6.17-dirty
4541 Image Type: PowerPC Linux Kernel Image (gzip compressed)
4542 Data Size: 1029343 Bytes = 1005.2 kB
4543 Load Address: 00000000
4544 Entry Point: 00000000
4545 Verifying Checksum ... OK
4546 Uncompressing Kernel Image ... OK
4547 Booting using flat device tree at 0x300000
4548 Using MPC85xx ADS machine description
4549 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
4553 More About U-Boot Image Types:
4554 ------------------------------
4556 U-Boot supports the following image types:
4558 "Standalone Programs" are directly runnable in the environment
4559 provided by U-Boot; it is expected that (if they behave
4560 well) you can continue to work in U-Boot after return from
4561 the Standalone Program.
4562 "OS Kernel Images" are usually images of some Embedded OS which
4563 will take over control completely. Usually these programs
4564 will install their own set of exception handlers, device
4565 drivers, set up the MMU, etc. - this means, that you cannot
4566 expect to re-enter U-Boot except by resetting the CPU.
4567 "RAMDisk Images" are more or less just data blocks, and their
4568 parameters (address, size) are passed to an OS kernel that is
4570 "Multi-File Images" contain several images, typically an OS
4571 (Linux) kernel image and one or more data images like
4572 RAMDisks. This construct is useful for instance when you want
4573 to boot over the network using BOOTP etc., where the boot
4574 server provides just a single image file, but you want to get
4575 for instance an OS kernel and a RAMDisk image.
4577 "Multi-File Images" start with a list of image sizes, each
4578 image size (in bytes) specified by an "uint32_t" in network
4579 byte order. This list is terminated by an "(uint32_t)0".
4580 Immediately after the terminating 0 follow the images, one by
4581 one, all aligned on "uint32_t" boundaries (size rounded up to
4582 a multiple of 4 bytes).
4584 "Firmware Images" are binary images containing firmware (like
4585 U-Boot or FPGA images) which usually will be programmed to
4588 "Script files" are command sequences that will be executed by
4589 U-Boot's command interpreter; this feature is especially
4590 useful when you configure U-Boot to use a real shell (hush)
4591 as command interpreter.
4593 Booting the Linux zImage:
4594 -------------------------
4596 On some platforms, it's possible to boot Linux zImage. This is done
4597 using the "bootz" command. The syntax of "bootz" command is the same
4598 as the syntax of "bootm" command.
4600 Note, defining the CONFIG_SUPPORT_RAW_INITRD allows user to supply
4601 kernel with raw initrd images. The syntax is slightly different, the
4602 address of the initrd must be augmented by it's size, in the following
4603 format: "<initrd addres>:<initrd size>".
4609 One of the features of U-Boot is that you can dynamically load and
4610 run "standalone" applications, which can use some resources of
4611 U-Boot like console I/O functions or interrupt services.
4613 Two simple examples are included with the sources:
4618 'examples/hello_world.c' contains a small "Hello World" Demo
4619 application; it is automatically compiled when you build U-Boot.
4620 It's configured to run at address 0x00040004, so you can play with it
4624 ## Ready for S-Record download ...
4625 ~>examples/hello_world.srec
4626 1 2 3 4 5 6 7 8 9 10 11 ...
4627 [file transfer complete]
4629 ## Start Addr = 0x00040004
4631 => go 40004 Hello World! This is a test.
4632 ## Starting application at 0x00040004 ...
4643 Hit any key to exit ...
4645 ## Application terminated, rc = 0x0
4647 Another example, which demonstrates how to register a CPM interrupt
4648 handler with the U-Boot code, can be found in 'examples/timer.c'.
4649 Here, a CPM timer is set up to generate an interrupt every second.
4650 The interrupt service routine is trivial, just printing a '.'
4651 character, but this is just a demo program. The application can be
4652 controlled by the following keys:
4654 ? - print current values og the CPM Timer registers
4655 b - enable interrupts and start timer
4656 e - stop timer and disable interrupts
4657 q - quit application
4660 ## Ready for S-Record download ...
4661 ~>examples/timer.srec
4662 1 2 3 4 5 6 7 8 9 10 11 ...
4663 [file transfer complete]
4665 ## Start Addr = 0x00040004
4668 ## Starting application at 0x00040004 ...
4671 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
4674 [q, b, e, ?] Set interval 1000000 us
4677 [q, b, e, ?] ........
4678 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
4681 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
4684 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
4687 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
4689 [q, b, e, ?] ...Stopping timer
4691 [q, b, e, ?] ## Application terminated, rc = 0x0
4697 Over time, many people have reported problems when trying to use the
4698 "minicom" terminal emulation program for serial download. I (wd)
4699 consider minicom to be broken, and recommend not to use it. Under
4700 Unix, I recommend to use C-Kermit for general purpose use (and
4701 especially for kermit binary protocol download ("loadb" command), and
4702 use "cu" for S-Record download ("loads" command). See
4703 http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
4704 for help with kermit.
4707 Nevertheless, if you absolutely want to use it try adding this
4708 configuration to your "File transfer protocols" section:
4710 Name Program Name U/D FullScr IO-Red. Multi
4711 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
4712 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
4718 Starting at version 0.9.2, U-Boot supports NetBSD both as host
4719 (build U-Boot) and target system (boots NetBSD/mpc8xx).
4721 Building requires a cross environment; it is known to work on
4722 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
4723 need gmake since the Makefiles are not compatible with BSD make).
4724 Note that the cross-powerpc package does not install include files;
4725 attempting to build U-Boot will fail because <machine/ansi.h> is
4726 missing. This file has to be installed and patched manually:
4728 # cd /usr/pkg/cross/powerpc-netbsd/include
4730 # ln -s powerpc machine
4731 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
4732 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
4734 Native builds *don't* work due to incompatibilities between native
4735 and U-Boot include files.
4737 Booting assumes that (the first part of) the image booted is a
4738 stage-2 loader which in turn loads and then invokes the kernel
4739 proper. Loader sources will eventually appear in the NetBSD source
4740 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
4741 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
4744 Implementation Internals:
4745 =========================
4747 The following is not intended to be a complete description of every
4748 implementation detail. However, it should help to understand the
4749 inner workings of U-Boot and make it easier to port it to custom
4753 Initial Stack, Global Data:
4754 ---------------------------
4756 The implementation of U-Boot is complicated by the fact that U-Boot
4757 starts running out of ROM (flash memory), usually without access to
4758 system RAM (because the memory controller is not initialized yet).
4759 This means that we don't have writable Data or BSS segments, and BSS
4760 is not initialized as zero. To be able to get a C environment working
4761 at all, we have to allocate at least a minimal stack. Implementation
4762 options for this are defined and restricted by the CPU used: Some CPU
4763 models provide on-chip memory (like the IMMR area on MPC8xx and
4764 MPC826x processors), on others (parts of) the data cache can be
4765 locked as (mis-) used as memory, etc.
4767 Chris Hallinan posted a good summary of these issues to the
4768 U-Boot mailing list:
4770 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
4771 From: "Chris Hallinan" <clh@net1plus.com>
4772 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
4775 Correct me if I'm wrong, folks, but the way I understand it
4776 is this: Using DCACHE as initial RAM for Stack, etc, does not
4777 require any physical RAM backing up the cache. The cleverness
4778 is that the cache is being used as a temporary supply of
4779 necessary storage before the SDRAM controller is setup. It's
4780 beyond the scope of this list to explain the details, but you
4781 can see how this works by studying the cache architecture and
4782 operation in the architecture and processor-specific manuals.
4784 OCM is On Chip Memory, which I believe the 405GP has 4K. It
4785 is another option for the system designer to use as an
4786 initial stack/RAM area prior to SDRAM being available. Either
4787 option should work for you. Using CS 4 should be fine if your
4788 board designers haven't used it for something that would
4789 cause you grief during the initial boot! It is frequently not
4792 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
4793 with your processor/board/system design. The default value
4794 you will find in any recent u-boot distribution in
4795 walnut.h should work for you. I'd set it to a value larger
4796 than your SDRAM module. If you have a 64MB SDRAM module, set
4797 it above 400_0000. Just make sure your board has no resources
4798 that are supposed to respond to that address! That code in
4799 start.S has been around a while and should work as is when
4800 you get the config right.
4805 It is essential to remember this, since it has some impact on the C
4806 code for the initialization procedures:
4808 * Initialized global data (data segment) is read-only. Do not attempt
4811 * Do not use any uninitialized global data (or implicitly initialized
4812 as zero data - BSS segment) at all - this is undefined, initiali-
4813 zation is performed later (when relocating to RAM).
4815 * Stack space is very limited. Avoid big data buffers or things like
4818 Having only the stack as writable memory limits means we cannot use
4819 normal global data to share information between the code. But it
4820 turned out that the implementation of U-Boot can be greatly
4821 simplified by making a global data structure (gd_t) available to all
4822 functions. We could pass a pointer to this data as argument to _all_
4823 functions, but this would bloat the code. Instead we use a feature of
4824 the GCC compiler (Global Register Variables) to share the data: we
4825 place a pointer (gd) to the global data into a register which we
4826 reserve for this purpose.
4828 When choosing a register for such a purpose we are restricted by the
4829 relevant (E)ABI specifications for the current architecture, and by
4830 GCC's implementation.
4832 For PowerPC, the following registers have specific use:
4834 R2: reserved for system use
4835 R3-R4: parameter passing and return values
4836 R5-R10: parameter passing
4837 R13: small data area pointer
4841 (U-Boot also uses R12 as internal GOT pointer. r12
4842 is a volatile register so r12 needs to be reset when
4843 going back and forth between asm and C)
4845 ==> U-Boot will use R2 to hold a pointer to the global data
4847 Note: on PPC, we could use a static initializer (since the
4848 address of the global data structure is known at compile time),
4849 but it turned out that reserving a register results in somewhat
4850 smaller code - although the code savings are not that big (on
4851 average for all boards 752 bytes for the whole U-Boot image,
4852 624 text + 127 data).
4854 On ARM, the following registers are used:
4856 R0: function argument word/integer result
4857 R1-R3: function argument word
4858 R9: platform specific
4859 R10: stack limit (used only if stack checking is enabled)
4860 R11: argument (frame) pointer
4861 R12: temporary workspace
4864 R15: program counter
4866 ==> U-Boot will use R9 to hold a pointer to the global data
4868 Note: on ARM, only R_ARM_RELATIVE relocations are supported.
4870 On Nios II, the ABI is documented here:
4871 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
4873 ==> U-Boot will use gp to hold a pointer to the global data
4875 Note: on Nios II, we give "-G0" option to gcc and don't use gp
4876 to access small data sections, so gp is free.
4878 On NDS32, the following registers are used:
4880 R0-R1: argument/return
4882 R15: temporary register for assembler
4883 R16: trampoline register
4884 R28: frame pointer (FP)
4885 R29: global pointer (GP)
4886 R30: link register (LP)
4887 R31: stack pointer (SP)
4888 PC: program counter (PC)
4890 ==> U-Boot will use R10 to hold a pointer to the global data
4892 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
4893 or current versions of GCC may "optimize" the code too much.
4895 On RISC-V, the following registers are used:
4897 x0: hard-wired zero (zero)
4898 x1: return address (ra)
4899 x2: stack pointer (sp)
4900 x3: global pointer (gp)
4901 x4: thread pointer (tp)
4902 x5: link register (t0)
4903 x8: frame pointer (fp)
4904 x10-x11: arguments/return values (a0-1)
4905 x12-x17: arguments (a2-7)
4906 x28-31: temporaries (t3-6)
4907 pc: program counter (pc)
4909 ==> U-Boot will use gp to hold a pointer to the global data
4914 U-Boot runs in system state and uses physical addresses, i.e. the
4915 MMU is not used either for address mapping nor for memory protection.
4917 The available memory is mapped to fixed addresses using the memory
4918 controller. In this process, a contiguous block is formed for each
4919 memory type (Flash, SDRAM, SRAM), even when it consists of several
4920 physical memory banks.
4922 U-Boot is installed in the first 128 kB of the first Flash bank (on
4923 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
4924 booting and sizing and initializing DRAM, the code relocates itself
4925 to the upper end of DRAM. Immediately below the U-Boot code some
4926 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
4927 configuration setting]. Below that, a structure with global Board
4928 Info data is placed, followed by the stack (growing downward).
4930 Additionally, some exception handler code is copied to the low 8 kB
4931 of DRAM (0x00000000 ... 0x00001FFF).
4933 So a typical memory configuration with 16 MB of DRAM could look like
4936 0x0000 0000 Exception Vector code
4939 0x0000 2000 Free for Application Use
4945 0x00FB FF20 Monitor Stack (Growing downward)
4946 0x00FB FFAC Board Info Data and permanent copy of global data
4947 0x00FC 0000 Malloc Arena
4950 0x00FE 0000 RAM Copy of Monitor Code
4951 ... eventually: LCD or video framebuffer
4952 ... eventually: pRAM (Protected RAM - unchanged by reset)
4953 0x00FF FFFF [End of RAM]
4956 System Initialization:
4957 ----------------------
4959 In the reset configuration, U-Boot starts at the reset entry point
4960 (on most PowerPC systems at address 0x00000100). Because of the reset
4961 configuration for CS0# this is a mirror of the on board Flash memory.
4962 To be able to re-map memory U-Boot then jumps to its link address.
4963 To be able to implement the initialization code in C, a (small!)
4964 initial stack is set up in the internal Dual Ported RAM (in case CPUs
4965 which provide such a feature like), or in a locked part of the data
4966 cache. After that, U-Boot initializes the CPU core, the caches and
4969 Next, all (potentially) available memory banks are mapped using a
4970 preliminary mapping. For example, we put them on 512 MB boundaries
4971 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
4972 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
4973 programmed for SDRAM access. Using the temporary configuration, a
4974 simple memory test is run that determines the size of the SDRAM
4977 When there is more than one SDRAM bank, and the banks are of
4978 different size, the largest is mapped first. For equal size, the first
4979 bank (CS2#) is mapped first. The first mapping is always for address
4980 0x00000000, with any additional banks following immediately to create
4981 contiguous memory starting from 0.
4983 Then, the monitor installs itself at the upper end of the SDRAM area
4984 and allocates memory for use by malloc() and for the global Board
4985 Info data; also, the exception vector code is copied to the low RAM
4986 pages, and the final stack is set up.
4988 Only after this relocation will you have a "normal" C environment;
4989 until that you are restricted in several ways, mostly because you are
4990 running from ROM, and because the code will have to be relocated to a
4994 U-Boot Porting Guide:
4995 ----------------------
4997 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
5001 int main(int argc, char *argv[])
5003 sighandler_t no_more_time;
5005 signal(SIGALRM, no_more_time);
5006 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
5008 if (available_money > available_manpower) {
5009 Pay consultant to port U-Boot;
5013 Download latest U-Boot source;
5015 Subscribe to u-boot mailing list;
5018 email("Hi, I am new to U-Boot, how do I get started?");
5021 Read the README file in the top level directory;
5022 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
5023 Read applicable doc/*.README;
5024 Read the source, Luke;
5025 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
5028 if (available_money > toLocalCurrency ($2500))
5031 Add a lot of aggravation and time;
5033 if (a similar board exists) { /* hopefully... */
5034 cp -a board/<similar> board/<myboard>
5035 cp include/configs/<similar>.h include/configs/<myboard>.h
5037 Create your own board support subdirectory;
5038 Create your own board include/configs/<myboard>.h file;
5040 Edit new board/<myboard> files
5041 Edit new include/configs/<myboard>.h
5046 Add / modify source code;
5050 email("Hi, I am having problems...");
5052 Send patch file to the U-Boot email list;
5053 if (reasonable critiques)
5054 Incorporate improvements from email list code review;
5056 Defend code as written;
5062 void no_more_time (int sig)
5071 All contributions to U-Boot should conform to the Linux kernel
5072 coding style; see the kernel coding style guide at
5073 https://www.kernel.org/doc/html/latest/process/coding-style.html, and the
5074 script "scripts/Lindent" in your Linux kernel source directory.
5076 Source files originating from a different project (for example the
5077 MTD subsystem) are generally exempt from these guidelines and are not
5078 reformatted to ease subsequent migration to newer versions of those
5081 Please note that U-Boot is implemented in C (and to some small parts in
5082 Assembler); no C++ is used, so please do not use C++ style comments (//)
5085 Please also stick to the following formatting rules:
5086 - remove any trailing white space
5087 - use TAB characters for indentation and vertical alignment, not spaces
5088 - make sure NOT to use DOS '\r\n' line feeds
5089 - do not add more than 2 consecutive empty lines to source files
5090 - do not add trailing empty lines to source files
5092 Submissions which do not conform to the standards may be returned
5093 with a request to reformat the changes.
5099 Since the number of patches for U-Boot is growing, we need to
5100 establish some rules. Submissions which do not conform to these rules
5101 may be rejected, even when they contain important and valuable stuff.
5103 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
5105 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
5106 see https://lists.denx.de/listinfo/u-boot
5108 When you send a patch, please include the following information with
5111 * For bug fixes: a description of the bug and how your patch fixes
5112 this bug. Please try to include a way of demonstrating that the
5113 patch actually fixes something.
5115 * For new features: a description of the feature and your
5118 * A CHANGELOG entry as plaintext (separate from the patch)
5120 * For major contributions, add a MAINTAINERS file with your
5121 information and associated file and directory references.
5123 * When you add support for a new board, don't forget to add a
5124 maintainer e-mail address to the boards.cfg file, too.
5126 * If your patch adds new configuration options, don't forget to
5127 document these in the README file.
5129 * The patch itself. If you are using git (which is *strongly*
5130 recommended) you can easily generate the patch using the
5131 "git format-patch". If you then use "git send-email" to send it to
5132 the U-Boot mailing list, you will avoid most of the common problems
5133 with some other mail clients.
5135 If you cannot use git, use "diff -purN OLD NEW". If your version of
5136 diff does not support these options, then get the latest version of
5139 The current directory when running this command shall be the parent
5140 directory of the U-Boot source tree (i. e. please make sure that
5141 your patch includes sufficient directory information for the
5144 We prefer patches as plain text. MIME attachments are discouraged,
5145 and compressed attachments must not be used.
5147 * If one logical set of modifications affects or creates several
5148 files, all these changes shall be submitted in a SINGLE patch file.
5150 * Changesets that contain different, unrelated modifications shall be
5151 submitted as SEPARATE patches, one patch per changeset.
5156 * Before sending the patch, run the buildman script on your patched
5157 source tree and make sure that no errors or warnings are reported
5158 for any of the boards.
5160 * Keep your modifications to the necessary minimum: A patch
5161 containing several unrelated changes or arbitrary reformats will be
5162 returned with a request to re-formatting / split it.
5164 * If you modify existing code, make sure that your new code does not
5165 add to the memory footprint of the code ;-) Small is beautiful!
5166 When adding new features, these should compile conditionally only
5167 (using #ifdef), and the resulting code with the new feature
5168 disabled must not need more memory than the old code without your
5171 * Remember that there is a size limit of 100 kB per message on the
5172 u-boot mailing list. Bigger patches will be moderated. If they are
5173 reasonable and not too big, they will be acknowledged. But patches
5174 bigger than the size limit should be avoided.