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 /avr32 Files generic to AVR32 architecture
140 /m68k Files generic to m68k architecture
141 /microblaze Files generic to microblaze architecture
142 /mips Files generic to MIPS architecture
143 /nds32 Files generic to NDS32 architecture
144 /nios2 Files generic to Altera NIOS2 architecture
145 /openrisc Files generic to OpenRISC architecture
146 /powerpc Files generic to PowerPC architecture
147 /sandbox Files generic to HW-independent "sandbox"
148 /sh Files generic to SH architecture
149 /sparc Files generic to SPARC architecture
150 /x86 Files generic to x86 architecture
151 /api Machine/arch independent API for external apps
152 /board Board dependent files
153 /cmd U-Boot commands functions
154 /common Misc architecture independent functions
155 /configs Board default configuration files
156 /disk Code for disk drive partition handling
157 /doc Documentation (don't expect too much)
158 /drivers Commonly used device drivers
159 /dts Contains Makefile for building internal U-Boot fdt.
160 /examples Example code for standalone applications, etc.
161 /fs Filesystem code (cramfs, ext2, jffs2, etc.)
162 /include Header Files
163 /lib Library routines generic to all architectures
164 /Licenses Various license files
166 /post Power On Self Test
167 /scripts Various build scripts and Makefiles
168 /test Various unit test files
169 /tools Tools to build S-Record or U-Boot images, etc.
171 Software Configuration:
172 =======================
174 Configuration is usually done using C preprocessor defines; the
175 rationale behind that is to avoid dead code whenever possible.
177 There are two classes of configuration variables:
179 * Configuration _OPTIONS_:
180 These are selectable by the user and have names beginning with
183 * Configuration _SETTINGS_:
184 These depend on the hardware etc. and should not be meddled with if
185 you don't know what you're doing; they have names beginning with
188 Previously, all configuration was done by hand, which involved creating
189 symbolic links and editing configuration files manually. More recently,
190 U-Boot has added the Kbuild infrastructure used by the Linux kernel,
191 allowing you to use the "make menuconfig" command to configure your
195 Selection of Processor Architecture and Board Type:
196 ---------------------------------------------------
198 For all supported boards there are ready-to-use default
199 configurations available; just type "make <board_name>_defconfig".
201 Example: For a TQM823L module type:
204 make TQM823L_defconfig
206 Note: If you're looking for the default configuration file for a board
207 you're sure used to be there but is now missing, check the file
208 doc/README.scrapyard for a list of no longer supported boards.
213 U-Boot can be built natively to run on a Linux host using the 'sandbox'
214 board. This allows feature development which is not board- or architecture-
215 specific to be undertaken on a native platform. The sandbox is also used to
216 run some of U-Boot's tests.
218 See board/sandbox/README.sandbox for more details.
221 Board Initialisation Flow:
222 --------------------------
224 This is the intended start-up flow for boards. This should apply for both
225 SPL and U-Boot proper (i.e. they both follow the same rules).
227 Note: "SPL" stands for "Secondary Program Loader," which is explained in
228 more detail later in this file.
230 At present, SPL mostly uses a separate code path, but the function names
231 and roles of each function are the same. Some boards or architectures
232 may not conform to this. At least most ARM boards which use
233 CONFIG_SPL_FRAMEWORK conform to this.
235 Execution typically starts with an architecture-specific (and possibly
236 CPU-specific) start.S file, such as:
238 - arch/arm/cpu/armv7/start.S
239 - arch/powerpc/cpu/mpc83xx/start.S
240 - arch/mips/cpu/start.S
242 and so on. From there, three functions are called; the purpose and
243 limitations of each of these functions are described below.
246 - purpose: essential init to permit execution to reach board_init_f()
247 - no global_data or BSS
248 - there is no stack (ARMv7 may have one but it will soon be removed)
249 - must not set up SDRAM or use console
250 - must only do the bare minimum to allow execution to continue to
252 - this is almost never needed
253 - return normally from this function
256 - purpose: set up the machine ready for running board_init_r():
257 i.e. SDRAM and serial UART
258 - global_data is available
260 - BSS is not available, so you cannot use global/static variables,
261 only stack variables and global_data
263 Non-SPL-specific notes:
264 - dram_init() is called to set up DRAM. If already done in SPL this
268 - you can override the entire board_init_f() function with your own
270 - preloader_console_init() can be called here in extremis
271 - should set up SDRAM, and anything needed to make the UART work
272 - these is no need to clear BSS, it will be done by crt0.S
273 - must return normally from this function (don't call board_init_r()
276 Here the BSS is cleared. For SPL, if CONFIG_SPL_STACK_R is defined, then at
277 this point the stack and global_data are relocated to below
278 CONFIG_SPL_STACK_R_ADDR. For non-SPL, U-Boot is relocated to run at the top of
282 - purpose: main execution, common code
283 - global_data is available
285 - BSS is available, all static/global variables can be used
286 - execution eventually continues to main_loop()
288 Non-SPL-specific notes:
289 - U-Boot is relocated to the top of memory and is now running from
293 - stack is optionally in SDRAM, if CONFIG_SPL_STACK_R is defined and
294 CONFIG_SPL_STACK_R_ADDR points into SDRAM
295 - preloader_console_init() can be called here - typically this is
296 done by defining CONFIG_SPL_BOARD_INIT and then supplying a
297 spl_board_init() function containing this call
298 - loads U-Boot or (in falcon mode) Linux
302 Configuration Options:
303 ----------------------
305 Configuration depends on the combination of board and CPU type; all
306 such information is kept in a configuration file
307 "include/configs/<board_name>.h".
309 Example: For a TQM823L module, all configuration settings are in
310 "include/configs/TQM823L.h".
313 Many of the options are named exactly as the corresponding Linux
314 kernel configuration options. The intention is to make it easier to
315 build a config tool - later.
318 The following options need to be configured:
320 - CPU Type: Define exactly one, e.g. CONFIG_MPC85XX.
322 - Board Type: Define exactly one, e.g. CONFIG_MPC8540ADS.
324 - CPU Daughterboard Type: (if CONFIG_ATSTK1000 is defined)
325 Define exactly one, e.g. CONFIG_ATSTK1002
327 - Marvell Family Member
328 CONFIG_SYS_MVFS - define it if you want to enable
329 multiple fs option at one time
330 for marvell soc family
332 - 8xx CPU Options: (if using an MPC8xx CPU)
333 CONFIG_8xx_GCLK_FREQ - deprecated: CPU clock if
334 get_gclk_freq() cannot work
335 e.g. if there is no 32KHz
336 reference PIT/RTC clock
337 CONFIG_8xx_OSCLK - PLL input clock (either EXTCLK
340 - 859/866/885 CPU options: (if using a MPC859 or MPC866 or MPC885 CPU):
341 CONFIG_SYS_8xx_CPUCLK_MIN
342 CONFIG_SYS_8xx_CPUCLK_MAX
343 CONFIG_8xx_CPUCLK_DEFAULT
344 See doc/README.MPC866
346 CONFIG_SYS_MEASURE_CPUCLK
348 Define this to measure the actual CPU clock instead
349 of relying on the correctness of the configured
350 values. Mostly useful for board bringup to make sure
351 the PLL is locked at the intended frequency. Note
352 that this requires a (stable) reference clock (32 kHz
353 RTC clock or CONFIG_SYS_8XX_XIN)
355 CONFIG_SYS_DELAYED_ICACHE
357 Define this option if you want to enable the
358 ICache only when Code runs from RAM.
363 Specifies that the core is a 64-bit PowerPC implementation (implements
364 the "64" category of the Power ISA). This is necessary for ePAPR
365 compliance, among other possible reasons.
367 CONFIG_SYS_FSL_TBCLK_DIV
369 Defines the core time base clock divider ratio compared to the
370 system clock. On most PQ3 devices this is 8, on newer QorIQ
371 devices it can be 16 or 32. The ratio varies from SoC to Soc.
373 CONFIG_SYS_FSL_PCIE_COMPAT
375 Defines the string to utilize when trying to match PCIe device
376 tree nodes for the given platform.
378 CONFIG_SYS_FSL_ERRATUM_A004510
380 Enables a workaround for erratum A004510. If set,
381 then CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV and
382 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY must be set.
384 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV
385 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV2 (optional)
387 Defines one or two SoC revisions (low 8 bits of SVR)
388 for which the A004510 workaround should be applied.
390 The rest of SVR is either not relevant to the decision
391 of whether the erratum is present (e.g. p2040 versus
392 p2041) or is implied by the build target, which controls
393 whether CONFIG_SYS_FSL_ERRATUM_A004510 is set.
395 See Freescale App Note 4493 for more information about
398 CONFIG_A003399_NOR_WORKAROUND
399 Enables a workaround for IFC erratum A003399. It is only
400 required during NOR boot.
402 CONFIG_A008044_WORKAROUND
403 Enables a workaround for T1040/T1042 erratum A008044. It is only
404 required during NAND boot and valid for Rev 1.0 SoC revision
406 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY
408 This is the value to write into CCSR offset 0x18600
409 according to the A004510 workaround.
411 CONFIG_SYS_FSL_DSP_DDR_ADDR
412 This value denotes start offset of DDR memory which is
413 connected exclusively to the DSP cores.
415 CONFIG_SYS_FSL_DSP_M2_RAM_ADDR
416 This value denotes start offset of M2 memory
417 which is directly connected to the DSP core.
419 CONFIG_SYS_FSL_DSP_M3_RAM_ADDR
420 This value denotes start offset of M3 memory which is directly
421 connected to the DSP core.
423 CONFIG_SYS_FSL_DSP_CCSRBAR_DEFAULT
424 This value denotes start offset of DSP CCSR space.
426 CONFIG_SYS_FSL_SINGLE_SOURCE_CLK
427 Single Source Clock is clocking mode present in some of FSL SoC's.
428 In this mode, a single differential clock is used to supply
429 clocks to the sysclock, ddrclock and usbclock.
431 CONFIG_SYS_CPC_REINIT_F
432 This CONFIG is defined when the CPC is configured as SRAM at the
433 time of U-Boot entry and is required to be re-initialized.
436 Indicates this SoC supports deep sleep feature. If deep sleep is
437 supported, core will start to execute uboot when wakes up.
439 - Generic CPU options:
440 CONFIG_SYS_GENERIC_GLOBAL_DATA
441 Defines global data is initialized in generic board board_init_f().
442 If this macro is defined, global data is created and cleared in
443 generic board board_init_f(). Without this macro, architecture/board
444 should initialize global data before calling board_init_f().
446 CONFIG_SYS_BIG_ENDIAN, CONFIG_SYS_LITTLE_ENDIAN
448 Defines the endianess of the CPU. Implementation of those
449 values is arch specific.
452 Freescale DDR driver in use. This type of DDR controller is
453 found in mpc83xx, mpc85xx, mpc86xx as well as some ARM core
456 CONFIG_SYS_FSL_DDR_ADDR
457 Freescale DDR memory-mapped register base.
459 CONFIG_SYS_FSL_DDR_EMU
460 Specify emulator support for DDR. Some DDR features such as
461 deskew training are not available.
463 CONFIG_SYS_FSL_DDRC_GEN1
464 Freescale DDR1 controller.
466 CONFIG_SYS_FSL_DDRC_GEN2
467 Freescale DDR2 controller.
469 CONFIG_SYS_FSL_DDRC_GEN3
470 Freescale DDR3 controller.
472 CONFIG_SYS_FSL_DDRC_GEN4
473 Freescale DDR4 controller.
475 CONFIG_SYS_FSL_DDRC_ARM_GEN3
476 Freescale DDR3 controller for ARM-based SoCs.
479 Board config to use DDR1. It can be enabled for SoCs with
480 Freescale DDR1 or DDR2 controllers, depending on the board
484 Board config to use DDR2. It can be enabled for SoCs with
485 Freescale DDR2 or DDR3 controllers, depending on the board
489 Board config to use DDR3. It can be enabled for SoCs with
490 Freescale DDR3 or DDR3L controllers.
493 Board config to use DDR3L. It can be enabled for SoCs with
497 Board config to use DDR4. It can be enabled for SoCs with
500 CONFIG_SYS_FSL_IFC_BE
501 Defines the IFC controller register space as Big Endian
503 CONFIG_SYS_FSL_IFC_LE
504 Defines the IFC controller register space as Little Endian
506 CONFIG_SYS_FSL_IFC_CLK_DIV
507 Defines divider of platform clock(clock input to IFC controller).
509 CONFIG_SYS_FSL_LBC_CLK_DIV
510 Defines divider of platform clock(clock input to eLBC controller).
512 CONFIG_SYS_FSL_PBL_PBI
513 It enables addition of RCW (Power on reset configuration) in built image.
514 Please refer doc/README.pblimage for more details
516 CONFIG_SYS_FSL_PBL_RCW
517 It adds PBI(pre-boot instructions) commands in u-boot build image.
518 PBI commands can be used to configure SoC before it starts the execution.
519 Please refer doc/README.pblimage for more details
522 It adds a target to create boot binary having SPL binary in PBI format
523 concatenated with u-boot binary.
525 CONFIG_SYS_FSL_DDR_BE
526 Defines the DDR controller register space as Big Endian
528 CONFIG_SYS_FSL_DDR_LE
529 Defines the DDR controller register space as Little Endian
531 CONFIG_SYS_FSL_DDR_SDRAM_BASE_PHY
532 Physical address from the view of DDR controllers. It is the
533 same as CONFIG_SYS_DDR_SDRAM_BASE for all Power SoCs. But
534 it could be different for ARM SoCs.
536 CONFIG_SYS_FSL_DDR_INTLV_256B
537 DDR controller interleaving on 256-byte. This is a special
538 interleaving mode, handled by Dickens for Freescale layerscape
541 CONFIG_SYS_FSL_DDR_MAIN_NUM_CTRLS
542 Number of controllers used as main memory.
544 CONFIG_SYS_FSL_OTHER_DDR_NUM_CTRLS
545 Number of controllers used for other than main memory.
547 CONFIG_SYS_FSL_HAS_DP_DDR
548 Defines the SoC has DP-DDR used for DPAA.
550 CONFIG_SYS_FSL_SEC_BE
551 Defines the SEC controller register space as Big Endian
553 CONFIG_SYS_FSL_SEC_LE
554 Defines the SEC controller register space as Little Endian
557 CONFIG_SYS_INIT_SP_OFFSET
559 Offset relative to CONFIG_SYS_SDRAM_BASE for initial stack
560 pointer. This is needed for the temporary stack before
563 CONFIG_SYS_MIPS_CACHE_MODE
565 Cache operation mode for the MIPS CPU.
566 See also arch/mips/include/asm/mipsregs.h.
568 CONF_CM_CACHABLE_NO_WA
571 CONF_CM_CACHABLE_NONCOHERENT
575 CONF_CM_CACHABLE_ACCELERATED
577 CONFIG_SYS_XWAY_EBU_BOOTCFG
579 Special option for Lantiq XWAY SoCs for booting from NOR flash.
580 See also arch/mips/cpu/mips32/start.S.
582 CONFIG_XWAY_SWAP_BYTES
584 Enable compilation of tools/xway-swap-bytes needed for Lantiq
585 XWAY SoCs for booting from NOR flash. The U-Boot image needs to
586 be swapped if a flash programmer is used.
589 CONFIG_SYS_EXCEPTION_VECTORS_HIGH
591 Select high exception vectors of the ARM core, e.g., do not
592 clear the V bit of the c1 register of CP15.
595 Generic timer clock source frequency.
597 COUNTER_FREQUENCY_REAL
598 Generic timer clock source frequency if the real clock is
599 different from COUNTER_FREQUENCY, and can only be determined
603 CONFIG_TEGRA_SUPPORT_NON_SECURE
605 Support executing U-Boot in non-secure (NS) mode. Certain
606 impossible actions will be skipped if the CPU is in NS mode,
607 such as ARM architectural timer initialization.
609 - Linux Kernel Interface:
612 U-Boot stores all clock information in Hz
613 internally. For binary compatibility with older Linux
614 kernels (which expect the clocks passed in the
615 bd_info data to be in MHz) the environment variable
616 "clocks_in_mhz" can be defined so that U-Boot
617 converts clock data to MHZ before passing it to the
619 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
620 "clocks_in_mhz=1" is automatically included in the
623 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
625 When transferring memsize parameter to Linux, some versions
626 expect it to be in bytes, others in MB.
627 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
631 New kernel versions are expecting firmware settings to be
632 passed using flattened device trees (based on open firmware
636 * New libfdt-based support
637 * Adds the "fdt" command
638 * The bootm command automatically updates the fdt
640 OF_CPU - The proper name of the cpus node (only required for
641 MPC512X and MPC5xxx based boards).
642 OF_SOC - The proper name of the soc node (only required for
643 MPC512X and MPC5xxx based boards).
644 OF_TBCLK - The timebase frequency.
645 OF_STDOUT_PATH - The path to the console device
647 boards with QUICC Engines require OF_QE to set UCC MAC
650 CONFIG_OF_BOARD_SETUP
652 Board code has addition modification that it wants to make
653 to the flat device tree before handing it off to the kernel
655 CONFIG_OF_SYSTEM_SETUP
657 Other code has addition modification that it wants to make
658 to the flat device tree before handing it off to the kernel.
659 This causes ft_system_setup() to be called before booting
664 U-Boot can detect if an IDE device is present or not.
665 If not, and this new config option is activated, U-Boot
666 removes the ATA node from the DTS before booting Linux,
667 so the Linux IDE driver does not probe the device and
668 crash. This is needed for buggy hardware (uc101) where
669 no pull down resistor is connected to the signal IDE5V_DD7.
671 CONFIG_MACH_TYPE [relevant for ARM only][mandatory]
673 This setting is mandatory for all boards that have only one
674 machine type and must be used to specify the machine type
675 number as it appears in the ARM machine registry
676 (see http://www.arm.linux.org.uk/developer/machines/).
677 Only boards that have multiple machine types supported
678 in a single configuration file and the machine type is
679 runtime discoverable, do not have to use this setting.
681 - vxWorks boot parameters:
683 bootvx constructs a valid bootline using the following
684 environments variables: bootdev, bootfile, ipaddr, netmask,
685 serverip, gatewayip, hostname, othbootargs.
686 It loads the vxWorks image pointed bootfile.
688 Note: If a "bootargs" environment is defined, it will overwride
689 the defaults discussed just above.
691 - Cache Configuration:
692 CONFIG_SYS_ICACHE_OFF - Do not enable instruction cache in U-Boot
693 CONFIG_SYS_DCACHE_OFF - Do not enable data cache in U-Boot
694 CONFIG_SYS_L2CACHE_OFF- Do not enable L2 cache in U-Boot
696 - Cache Configuration for ARM:
697 CONFIG_SYS_L2_PL310 - Enable support for ARM PL310 L2 cache
699 CONFIG_SYS_PL310_BASE - Physical base address of PL310
700 controller register space
705 Define this if you want support for Amba PrimeCell PL010 UARTs.
709 Define this if you want support for Amba PrimeCell PL011 UARTs.
713 If you have Amba PrimeCell PL011 UARTs, set this variable to
714 the clock speed of the UARTs.
718 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
719 define this to a list of base addresses for each (supported)
720 port. See e.g. include/configs/versatile.h
722 CONFIG_SERIAL_HW_FLOW_CONTROL
724 Define this variable to enable hw flow control in serial driver.
725 Current user of this option is drivers/serial/nsl16550.c driver
728 Depending on board, define exactly one serial port
729 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
730 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
731 console by defining CONFIG_8xx_CONS_NONE
733 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
734 port routines must be defined elsewhere
735 (i.e. serial_init(), serial_getc(), ...)
738 CONFIG_BAUDRATE - in bps
739 Select one of the baudrates listed in
740 CONFIG_SYS_BAUDRATE_TABLE, see below.
741 CONFIG_SYS_BRGCLK_PRESCALE, baudrate prescale
743 - Console Rx buffer length
744 With CONFIG_SYS_SMC_RXBUFLEN it is possible to define
745 the maximum receive buffer length for the SMC.
746 This option is actual only for 82xx and 8xx possible.
747 If using CONFIG_SYS_SMC_RXBUFLEN also CONFIG_SYS_MAXIDLE
748 must be defined, to setup the maximum idle timeout for
753 Only needed when CONFIG_BOOTDELAY is enabled;
754 define a command string that is automatically executed
755 when no character is read on the console interface
756 within "Boot Delay" after reset.
759 This can be used to pass arguments to the bootm
760 command. The value of CONFIG_BOOTARGS goes into the
761 environment value "bootargs".
763 CONFIG_RAMBOOT and CONFIG_NFSBOOT
764 The value of these goes into the environment as
765 "ramboot" and "nfsboot" respectively, and can be used
766 as a convenience, when switching between booting from
770 CONFIG_BOOTCOUNT_LIMIT
771 Implements a mechanism for detecting a repeating reboot
773 http://www.denx.de/wiki/view/DULG/UBootBootCountLimit
776 If no softreset save registers are found on the hardware
777 "bootcount" is stored in the environment. To prevent a
778 saveenv on all reboots, the environment variable
779 "upgrade_available" is used. If "upgrade_available" is
780 0, "bootcount" is always 0, if "upgrade_available" is
781 1 "bootcount" is incremented in the environment.
782 So the Userspace Applikation must set the "upgrade_available"
783 and "bootcount" variable to 0, if a boot was successfully.
788 When this option is #defined, the existence of the
789 environment variable "preboot" will be checked
790 immediately before starting the CONFIG_BOOTDELAY
791 countdown and/or running the auto-boot command resp.
792 entering interactive mode.
794 This feature is especially useful when "preboot" is
795 automatically generated or modified. For an example
796 see the LWMON board specific code: here "preboot" is
797 modified when the user holds down a certain
798 combination of keys on the (special) keyboard when
801 - Serial Download Echo Mode:
803 If defined to 1, all characters received during a
804 serial download (using the "loads" command) are
805 echoed back. This might be needed by some terminal
806 emulations (like "cu"), but may as well just take
807 time on others. This setting #define's the initial
808 value of the "loads_echo" environment variable.
810 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
812 Select one of the baudrates listed in
813 CONFIG_SYS_BAUDRATE_TABLE, see below.
816 Monitor commands can be included or excluded
817 from the build by using the #include files
818 <config_cmd_all.h> and #undef'ing unwanted
819 commands, or adding #define's for wanted commands.
821 The default command configuration includes all commands
822 except those marked below with a "*".
824 CONFIG_CMD_AES AES 128 CBC encrypt/decrypt
825 CONFIG_CMD_ASKENV * ask for env variable
826 CONFIG_CMD_BDI bdinfo
827 CONFIG_CMD_BEDBUG * Include BedBug Debugger
828 CONFIG_CMD_BMP * BMP support
829 CONFIG_CMD_BSP * Board specific commands
830 CONFIG_CMD_BOOTD bootd
831 CONFIG_CMD_BOOTI * ARM64 Linux kernel Image support
832 CONFIG_CMD_CACHE * icache, dcache
833 CONFIG_CMD_CLK * clock command support
834 CONFIG_CMD_CONSOLE coninfo
835 CONFIG_CMD_CRC32 * crc32
836 CONFIG_CMD_DATE * support for RTC, date/time...
837 CONFIG_CMD_DHCP * DHCP support
838 CONFIG_CMD_DIAG * Diagnostics
839 CONFIG_CMD_DS4510 * ds4510 I2C gpio commands
840 CONFIG_CMD_DS4510_INFO * ds4510 I2C info command
841 CONFIG_CMD_DS4510_MEM * ds4510 I2C eeprom/sram commansd
842 CONFIG_CMD_DS4510_RST * ds4510 I2C rst command
843 CONFIG_CMD_DTT * Digital Therm and Thermostat
844 CONFIG_CMD_ECHO echo arguments
845 CONFIG_CMD_EDITENV edit env variable
846 CONFIG_CMD_EEPROM * EEPROM read/write support
847 CONFIG_CMD_EEPROM_LAYOUT* EEPROM layout aware commands
848 CONFIG_CMD_ELF * bootelf, bootvx
849 CONFIG_CMD_ENV_CALLBACK * display details about env callbacks
850 CONFIG_CMD_ENV_FLAGS * display details about env flags
851 CONFIG_CMD_ENV_EXISTS * check existence of env variable
852 CONFIG_CMD_EXPORTENV * export the environment
853 CONFIG_CMD_EXT2 * ext2 command support
854 CONFIG_CMD_EXT4 * ext4 command support
855 CONFIG_CMD_FS_GENERIC * filesystem commands (e.g. load, ls)
856 that work for multiple fs types
857 CONFIG_CMD_FS_UUID * Look up a filesystem UUID
858 CONFIG_CMD_SAVEENV saveenv
859 CONFIG_CMD_FDC * Floppy Disk Support
860 CONFIG_CMD_FAT * FAT command support
861 CONFIG_CMD_FLASH flinfo, erase, protect
862 CONFIG_CMD_FPGA FPGA device initialization support
863 CONFIG_CMD_FUSE * Device fuse support
864 CONFIG_CMD_GETTIME * Get time since boot
865 CONFIG_CMD_GO * the 'go' command (exec code)
866 CONFIG_CMD_GREPENV * search environment
867 CONFIG_CMD_HASH * calculate hash / digest
868 CONFIG_CMD_I2C * I2C serial bus support
869 CONFIG_CMD_IDE * IDE harddisk support
870 CONFIG_CMD_IMI iminfo
871 CONFIG_CMD_IMLS List all images found in NOR flash
872 CONFIG_CMD_IMLS_NAND * List all images found in NAND flash
873 CONFIG_CMD_IMMAP * IMMR dump support
874 CONFIG_CMD_IOTRACE * I/O tracing for debugging
875 CONFIG_CMD_IMPORTENV * import an environment
876 CONFIG_CMD_INI * import data from an ini file into the env
877 CONFIG_CMD_IRQ * irqinfo
878 CONFIG_CMD_ITEST Integer/string test of 2 values
879 CONFIG_CMD_JFFS2 * JFFS2 Support
880 CONFIG_CMD_KGDB * kgdb
881 CONFIG_CMD_LDRINFO * ldrinfo (display Blackfin loader)
882 CONFIG_CMD_LINK_LOCAL * link-local IP address auto-configuration
884 CONFIG_CMD_LOADB loadb
885 CONFIG_CMD_LOADS loads
886 CONFIG_CMD_MD5SUM * print md5 message digest
887 (requires CONFIG_CMD_MEMORY and CONFIG_MD5)
888 CONFIG_CMD_MEMINFO * Display detailed memory information
889 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
891 CONFIG_CMD_MEMTEST * mtest
892 CONFIG_CMD_MISC Misc functions like sleep etc
893 CONFIG_CMD_MMC * MMC memory mapped support
894 CONFIG_CMD_MII * MII utility commands
895 CONFIG_CMD_MTDPARTS * MTD partition support
896 CONFIG_CMD_NAND * NAND support
897 CONFIG_CMD_NET bootp, tftpboot, rarpboot
898 CONFIG_CMD_NFS NFS support
899 CONFIG_CMD_PCA953X * PCA953x I2C gpio commands
900 CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command
901 CONFIG_CMD_PCI * pciinfo
902 CONFIG_CMD_PCMCIA * PCMCIA support
903 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
905 CONFIG_CMD_PORTIO * Port I/O
906 CONFIG_CMD_READ * Read raw data from partition
907 CONFIG_CMD_REGINFO * Register dump
908 CONFIG_CMD_RUN run command in env variable
909 CONFIG_CMD_SANDBOX * sb command to access sandbox features
910 CONFIG_CMD_SAVES * save S record dump
911 CONFIG_SCSI * SCSI Support
912 CONFIG_CMD_SDRAM * print SDRAM configuration information
913 (requires CONFIG_CMD_I2C)
914 CONFIG_CMD_SETGETDCR Support for DCR Register access
916 CONFIG_CMD_SF * Read/write/erase SPI NOR flash
917 CONFIG_CMD_SHA1SUM * print sha1 memory digest
918 (requires CONFIG_CMD_MEMORY)
919 CONFIG_CMD_SOFTSWITCH * Soft switch setting command for BF60x
920 CONFIG_CMD_SOURCE "source" command Support
921 CONFIG_CMD_SPI * SPI serial bus support
922 CONFIG_CMD_TFTPSRV * TFTP transfer in server mode
923 CONFIG_CMD_TFTPPUT * TFTP put command (upload)
924 CONFIG_CMD_TIME * run command and report execution time (ARM specific)
925 CONFIG_CMD_TIMER * access to the system tick timer
926 CONFIG_CMD_USB * USB support
927 CONFIG_CMD_CDP * Cisco Discover Protocol support
928 CONFIG_CMD_MFSL * Microblaze FSL support
929 CONFIG_CMD_XIMG Load part of Multi Image
930 CONFIG_CMD_UUID * Generate random UUID or GUID string
932 EXAMPLE: If you want all functions except of network
933 support you can write:
935 #include "config_cmd_all.h"
936 #undef CONFIG_CMD_NET
939 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
941 Note: Don't enable the "icache" and "dcache" commands
942 (configuration option CONFIG_CMD_CACHE) unless you know
943 what you (and your U-Boot users) are doing. Data
944 cache cannot be enabled on systems like the 8xx or
945 8260 (where accesses to the IMMR region must be
946 uncached), and it cannot be disabled on all other
947 systems where we (mis-) use the data cache to hold an
948 initial stack and some data.
951 XXX - this list needs to get updated!
953 - Removal of commands
954 If no commands are needed to boot, you can disable
955 CONFIG_CMDLINE to remove them. In this case, the command line
956 will not be available, and when U-Boot wants to execute the
957 boot command (on start-up) it will call board_run_command()
958 instead. This can reduce image size significantly for very
959 simple boot procedures.
961 - Regular expression support:
963 If this variable is defined, U-Boot is linked against
964 the SLRE (Super Light Regular Expression) library,
965 which adds regex support to some commands, as for
966 example "env grep" and "setexpr".
970 If this variable is defined, U-Boot will use a device tree
971 to configure its devices, instead of relying on statically
972 compiled #defines in the board file. This option is
973 experimental and only available on a few boards. The device
974 tree is available in the global data as gd->fdt_blob.
976 U-Boot needs to get its device tree from somewhere. This can
977 be done using one of the two options below:
980 If this variable is defined, U-Boot will embed a device tree
981 binary in its image. This device tree file should be in the
982 board directory and called <soc>-<board>.dts. The binary file
983 is then picked up in board_init_f() and made available through
984 the global data structure as gd->blob.
987 If this variable is defined, U-Boot will build a device tree
988 binary. It will be called u-boot.dtb. Architecture-specific
989 code will locate it at run-time. Generally this works by:
991 cat u-boot.bin u-boot.dtb >image.bin
993 and in fact, U-Boot does this for you, creating a file called
994 u-boot-dtb.bin which is useful in the common case. You can
995 still use the individual files if you need something more
1000 If this variable is defined, it enables watchdog
1001 support for the SoC. There must be support in the SoC
1002 specific code for a watchdog. For the 8xx and 8260
1003 CPUs, the SIU Watchdog feature is enabled in the SYPCR
1004 register. When supported for a specific SoC is
1005 available, then no further board specific code should
1006 be needed to use it.
1009 When using a watchdog circuitry external to the used
1010 SoC, then define this variable and provide board
1011 specific code for the "hw_watchdog_reset" function.
1013 CONFIG_AT91_HW_WDT_TIMEOUT
1014 specify the timeout in seconds. default 2 seconds.
1017 CONFIG_VERSION_VARIABLE
1018 If this variable is defined, an environment variable
1019 named "ver" is created by U-Boot showing the U-Boot
1020 version as printed by the "version" command.
1021 Any change to this variable will be reverted at the
1026 When CONFIG_CMD_DATE is selected, the type of the RTC
1027 has to be selected, too. Define exactly one of the
1030 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
1031 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
1032 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC
1033 CONFIG_RTC_MC146818 - use MC146818 RTC
1034 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
1035 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
1036 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
1037 CONFIG_RTC_DS1339 - use Maxim, Inc. DS1339 RTC
1038 CONFIG_RTC_DS164x - use Dallas DS164x RTC
1039 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
1040 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
1041 CONFIG_SYS_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
1042 CONFIG_SYS_RV3029_TCR - enable trickle charger on
1045 Note that if the RTC uses I2C, then the I2C interface
1046 must also be configured. See I2C Support, below.
1049 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
1051 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
1052 chip-ngpio pairs that tell the PCA953X driver the number of
1053 pins supported by a particular chip.
1055 Note that if the GPIO device uses I2C, then the I2C interface
1056 must also be configured. See I2C Support, below.
1059 When CONFIG_IO_TRACE is selected, U-Boot intercepts all I/O
1060 accesses and can checksum them or write a list of them out
1061 to memory. See the 'iotrace' command for details. This is
1062 useful for testing device drivers since it can confirm that
1063 the driver behaves the same way before and after a code
1064 change. Currently this is supported on sandbox and arm. To
1065 add support for your architecture, add '#include <iotrace.h>'
1066 to the bottom of arch/<arch>/include/asm/io.h and test.
1068 Example output from the 'iotrace stats' command is below.
1069 Note that if the trace buffer is exhausted, the checksum will
1070 still continue to operate.
1073 Start: 10000000 (buffer start address)
1074 Size: 00010000 (buffer size)
1075 Offset: 00000120 (current buffer offset)
1076 Output: 10000120 (start + offset)
1077 Count: 00000018 (number of trace records)
1078 CRC32: 9526fb66 (CRC32 of all trace records)
1080 - Timestamp Support:
1082 When CONFIG_TIMESTAMP is selected, the timestamp
1083 (date and time) of an image is printed by image
1084 commands like bootm or iminfo. This option is
1085 automatically enabled when you select CONFIG_CMD_DATE .
1087 - Partition Labels (disklabels) Supported:
1088 Zero or more of the following:
1089 CONFIG_MAC_PARTITION Apple's MacOS partition table.
1090 CONFIG_DOS_PARTITION MS Dos partition table, traditional on the
1091 Intel architecture, USB sticks, etc.
1092 CONFIG_ISO_PARTITION ISO partition table, used on CDROM etc.
1093 CONFIG_EFI_PARTITION GPT partition table, common when EFI is the
1094 bootloader. Note 2TB partition limit; see
1096 CONFIG_MTD_PARTITIONS Memory Technology Device partition table.
1098 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
1099 CONFIG_SCSI) you must configure support for at
1100 least one non-MTD partition type as well.
1103 CONFIG_IDE_RESET_ROUTINE - this is defined in several
1104 board configurations files but used nowhere!
1106 CONFIG_IDE_RESET - is this is defined, IDE Reset will
1107 be performed by calling the function
1108 ide_set_reset(int reset)
1109 which has to be defined in a board specific file
1114 Set this to enable ATAPI support.
1119 Set this to enable support for disks larger than 137GB
1120 Also look at CONFIG_SYS_64BIT_LBA.
1121 Whithout these , LBA48 support uses 32bit variables and will 'only'
1122 support disks up to 2.1TB.
1124 CONFIG_SYS_64BIT_LBA:
1125 When enabled, makes the IDE subsystem use 64bit sector addresses.
1129 At the moment only there is only support for the
1130 SYM53C8XX SCSI controller; define
1131 CONFIG_SCSI_SYM53C8XX to enable it.
1133 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
1134 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
1135 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
1136 maximum numbers of LUNs, SCSI ID's and target
1138 CONFIG_SYS_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
1140 The environment variable 'scsidevs' is set to the number of
1141 SCSI devices found during the last scan.
1143 - NETWORK Support (PCI):
1145 Support for Intel 8254x/8257x gigabit chips.
1148 Utility code for direct access to the SPI bus on Intel 8257x.
1149 This does not do anything useful unless you set at least one
1150 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
1152 CONFIG_E1000_SPI_GENERIC
1153 Allow generic access to the SPI bus on the Intel 8257x, for
1154 example with the "sspi" command.
1157 Management command for E1000 devices. When used on devices
1158 with SPI support you can reprogram the EEPROM from U-Boot.
1161 Support for Intel 82557/82559/82559ER chips.
1162 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
1163 write routine for first time initialisation.
1166 Support for Digital 2114x chips.
1167 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
1168 modem chip initialisation (KS8761/QS6611).
1171 Support for National dp83815 chips.
1174 Support for National dp8382[01] gigabit chips.
1176 - NETWORK Support (other):
1178 CONFIG_DRIVER_AT91EMAC
1179 Support for AT91RM9200 EMAC.
1182 Define this to use reduced MII inteface
1184 CONFIG_DRIVER_AT91EMAC_QUIET
1185 If this defined, the driver is quiet.
1186 The driver doen't show link status messages.
1188 CONFIG_CALXEDA_XGMAC
1189 Support for the Calxeda XGMAC device
1192 Support for SMSC's LAN91C96 chips.
1194 CONFIG_LAN91C96_USE_32_BIT
1195 Define this to enable 32 bit addressing
1198 Support for SMSC's LAN91C111 chip
1200 CONFIG_SMC91111_BASE
1201 Define this to hold the physical address
1202 of the device (I/O space)
1204 CONFIG_SMC_USE_32_BIT
1205 Define this if data bus is 32 bits
1207 CONFIG_SMC_USE_IOFUNCS
1208 Define this to use i/o functions instead of macros
1209 (some hardware wont work with macros)
1211 CONFIG_DRIVER_TI_EMAC
1212 Support for davinci emac
1214 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
1215 Define this if you have more then 3 PHYs.
1218 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
1220 CONFIG_FTGMAC100_EGIGA
1221 Define this to use GE link update with gigabit PHY.
1222 Define this if FTGMAC100 is connected to gigabit PHY.
1223 If your system has 10/100 PHY only, it might not occur
1224 wrong behavior. Because PHY usually return timeout or
1225 useless data when polling gigabit status and gigabit
1226 control registers. This behavior won't affect the
1227 correctnessof 10/100 link speed update.
1230 Support for SMSC's LAN911x and LAN921x chips
1233 Define this to hold the physical address
1234 of the device (I/O space)
1236 CONFIG_SMC911X_32_BIT
1237 Define this if data bus is 32 bits
1239 CONFIG_SMC911X_16_BIT
1240 Define this if data bus is 16 bits. If your processor
1241 automatically converts one 32 bit word to two 16 bit
1242 words you may also try CONFIG_SMC911X_32_BIT.
1245 Support for Renesas on-chip Ethernet controller
1247 CONFIG_SH_ETHER_USE_PORT
1248 Define the number of ports to be used
1250 CONFIG_SH_ETHER_PHY_ADDR
1251 Define the ETH PHY's address
1253 CONFIG_SH_ETHER_CACHE_WRITEBACK
1254 If this option is set, the driver enables cache flush.
1258 Support for PWM module on the imx6.
1262 Support TPM devices.
1264 CONFIG_TPM_TIS_INFINEON
1265 Support for Infineon i2c bus TPM devices. Only one device
1266 per system is supported at this time.
1268 CONFIG_TPM_TIS_I2C_BURST_LIMITATION
1269 Define the burst count bytes upper limit
1272 Support for STMicroelectronics TPM devices. Requires DM_TPM support.
1274 CONFIG_TPM_ST33ZP24_I2C
1275 Support for STMicroelectronics ST33ZP24 I2C devices.
1276 Requires TPM_ST33ZP24 and I2C.
1278 CONFIG_TPM_ST33ZP24_SPI
1279 Support for STMicroelectronics ST33ZP24 SPI devices.
1280 Requires TPM_ST33ZP24 and SPI.
1282 CONFIG_TPM_ATMEL_TWI
1283 Support for Atmel TWI TPM device. Requires I2C support.
1286 Support for generic parallel port TPM devices. Only one device
1287 per system is supported at this time.
1289 CONFIG_TPM_TIS_BASE_ADDRESS
1290 Base address where the generic TPM device is mapped
1291 to. Contemporary x86 systems usually map it at
1295 Add tpm monitor functions.
1296 Requires CONFIG_TPM. If CONFIG_TPM_AUTH_SESSIONS is set, also
1297 provides monitor access to authorized functions.
1300 Define this to enable the TPM support library which provides
1301 functional interfaces to some TPM commands.
1302 Requires support for a TPM device.
1304 CONFIG_TPM_AUTH_SESSIONS
1305 Define this to enable authorized functions in the TPM library.
1306 Requires CONFIG_TPM and CONFIG_SHA1.
1309 At the moment only the UHCI host controller is
1310 supported (PIP405, MIP405, MPC5200); define
1311 CONFIG_USB_UHCI to enable it.
1312 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
1313 and define CONFIG_USB_STORAGE to enable the USB
1316 Supported are USB Keyboards and USB Floppy drives
1318 MPC5200 USB requires additional defines:
1320 for 528 MHz Clock: 0x0001bbbb
1324 for differential drivers: 0x00001000
1325 for single ended drivers: 0x00005000
1326 for differential drivers on PSC3: 0x00000100
1327 for single ended drivers on PSC3: 0x00004100
1328 CONFIG_SYS_USB_EVENT_POLL
1329 May be defined to allow interrupt polling
1330 instead of using asynchronous interrupts
1332 CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
1333 txfilltuning field in the EHCI controller on reset.
1335 CONFIG_USB_DWC2_REG_ADDR the physical CPU address of the DWC2
1336 HW module registers.
1339 Define the below if you wish to use the USB console.
1340 Once firmware is rebuilt from a serial console issue the
1341 command "setenv stdin usbtty; setenv stdout usbtty" and
1342 attach your USB cable. The Unix command "dmesg" should print
1343 it has found a new device. The environment variable usbtty
1344 can be set to gserial or cdc_acm to enable your device to
1345 appear to a USB host as a Linux gserial device or a
1346 Common Device Class Abstract Control Model serial device.
1347 If you select usbtty = gserial you should be able to enumerate
1349 # modprobe usbserial vendor=0xVendorID product=0xProductID
1350 else if using cdc_acm, simply setting the environment
1351 variable usbtty to be cdc_acm should suffice. The following
1352 might be defined in YourBoardName.h
1355 Define this to build a UDC device
1358 Define this to have a tty type of device available to
1359 talk to the UDC device
1362 Define this to enable the high speed support for usb
1363 device and usbtty. If this feature is enabled, a routine
1364 int is_usbd_high_speed(void)
1365 also needs to be defined by the driver to dynamically poll
1366 whether the enumeration has succeded at high speed or full
1369 CONFIG_SYS_CONSOLE_IS_IN_ENV
1370 Define this if you want stdin, stdout &/or stderr to
1374 CONFIG_SYS_USB_EXTC_CLK 0xBLAH
1375 Derive USB clock from external clock "blah"
1376 - CONFIG_SYS_USB_EXTC_CLK 0x02
1378 If you have a USB-IF assigned VendorID then you may wish to
1379 define your own vendor specific values either in BoardName.h
1380 or directly in usbd_vendor_info.h. If you don't define
1381 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
1382 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
1383 should pretend to be a Linux device to it's target host.
1385 CONFIG_USBD_MANUFACTURER
1386 Define this string as the name of your company for
1387 - CONFIG_USBD_MANUFACTURER "my company"
1389 CONFIG_USBD_PRODUCT_NAME
1390 Define this string as the name of your product
1391 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
1393 CONFIG_USBD_VENDORID
1394 Define this as your assigned Vendor ID from the USB
1395 Implementors Forum. This *must* be a genuine Vendor ID
1396 to avoid polluting the USB namespace.
1397 - CONFIG_USBD_VENDORID 0xFFFF
1399 CONFIG_USBD_PRODUCTID
1400 Define this as the unique Product ID
1402 - CONFIG_USBD_PRODUCTID 0xFFFF
1404 - ULPI Layer Support:
1405 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
1406 the generic ULPI layer. The generic layer accesses the ULPI PHY
1407 via the platform viewport, so you need both the genric layer and
1408 the viewport enabled. Currently only Chipidea/ARC based
1409 viewport is supported.
1410 To enable the ULPI layer support, define CONFIG_USB_ULPI and
1411 CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
1412 If your ULPI phy needs a different reference clock than the
1413 standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to
1414 the appropriate value in Hz.
1417 The MMC controller on the Intel PXA is supported. To
1418 enable this define CONFIG_MMC. The MMC can be
1419 accessed from the boot prompt by mapping the device
1420 to physical memory similar to flash. Command line is
1421 enabled with CONFIG_CMD_MMC. The MMC driver also works with
1422 the FAT fs. This is enabled with CONFIG_CMD_FAT.
1425 Support for Renesas on-chip MMCIF controller
1427 CONFIG_SH_MMCIF_ADDR
1428 Define the base address of MMCIF registers
1431 Define the clock frequency for MMCIF
1433 CONFIG_SUPPORT_EMMC_BOOT
1434 Enable some additional features of the eMMC boot partitions.
1436 CONFIG_SUPPORT_EMMC_RPMB
1437 Enable the commands for reading, writing and programming the
1438 key for the Replay Protection Memory Block partition in eMMC.
1440 - USB Device Firmware Update (DFU) class support:
1441 CONFIG_USB_FUNCTION_DFU
1442 This enables the USB portion of the DFU USB class
1445 This enables the command "dfu" which is used to have
1446 U-Boot create a DFU class device via USB. This command
1447 requires that the "dfu_alt_info" environment variable be
1448 set and define the alt settings to expose to the host.
1451 This enables support for exposing (e)MMC devices via DFU.
1454 This enables support for exposing NAND devices via DFU.
1457 This enables support for exposing RAM via DFU.
1458 Note: DFU spec refer to non-volatile memory usage, but
1459 allow usages beyond the scope of spec - here RAM usage,
1460 one that would help mostly the developer.
1462 CONFIG_SYS_DFU_DATA_BUF_SIZE
1463 Dfu transfer uses a buffer before writing data to the
1464 raw storage device. Make the size (in bytes) of this buffer
1465 configurable. The size of this buffer is also configurable
1466 through the "dfu_bufsiz" environment variable.
1468 CONFIG_SYS_DFU_MAX_FILE_SIZE
1469 When updating files rather than the raw storage device,
1470 we use a static buffer to copy the file into and then write
1471 the buffer once we've been given the whole file. Define
1472 this to the maximum filesize (in bytes) for the buffer.
1473 Default is 4 MiB if undefined.
1475 DFU_DEFAULT_POLL_TIMEOUT
1476 Poll timeout [ms], is the timeout a device can send to the
1477 host. The host must wait for this timeout before sending
1478 a subsequent DFU_GET_STATUS request to the device.
1480 DFU_MANIFEST_POLL_TIMEOUT
1481 Poll timeout [ms], which the device sends to the host when
1482 entering dfuMANIFEST state. Host waits this timeout, before
1483 sending again an USB request to the device.
1485 - USB Device Android Fastboot support:
1486 CONFIG_USB_FUNCTION_FASTBOOT
1487 This enables the USB part of the fastboot gadget
1490 This enables the command "fastboot" which enables the Android
1491 fastboot mode for the platform's USB device. Fastboot is a USB
1492 protocol for downloading images, flashing and device control
1493 used on Android devices.
1494 See doc/README.android-fastboot for more information.
1496 CONFIG_ANDROID_BOOT_IMAGE
1497 This enables support for booting images which use the Android
1498 image format header.
1500 CONFIG_FASTBOOT_BUF_ADDR
1501 The fastboot protocol requires a large memory buffer for
1502 downloads. Define this to the starting RAM address to use for
1505 CONFIG_FASTBOOT_BUF_SIZE
1506 The fastboot protocol requires a large memory buffer for
1507 downloads. This buffer should be as large as possible for a
1508 platform. Define this to the size available RAM for fastboot.
1510 CONFIG_FASTBOOT_FLASH
1511 The fastboot protocol includes a "flash" command for writing
1512 the downloaded image to a non-volatile storage device. Define
1513 this to enable the "fastboot flash" command.
1515 CONFIG_FASTBOOT_FLASH_MMC_DEV
1516 The fastboot "flash" command requires additional information
1517 regarding the non-volatile storage device. Define this to
1518 the eMMC device that fastboot should use to store the image.
1520 CONFIG_FASTBOOT_GPT_NAME
1521 The fastboot "flash" command supports writing the downloaded
1522 image to the Protective MBR and the Primary GUID Partition
1523 Table. (Additionally, this downloaded image is post-processed
1524 to generate and write the Backup GUID Partition Table.)
1525 This occurs when the specified "partition name" on the
1526 "fastboot flash" command line matches this value.
1527 The default is "gpt" if undefined.
1529 CONFIG_FASTBOOT_MBR_NAME
1530 The fastboot "flash" command supports writing the downloaded
1532 This occurs when the "partition name" specified on the
1533 "fastboot flash" command line matches this value.
1534 If not defined the default value "mbr" is used.
1536 - Journaling Flash filesystem support:
1538 Define these for a default partition on a NAND device
1540 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1541 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1542 Define these for a default partition on a NOR device
1544 - FAT(File Allocation Table) filesystem write function support:
1547 Define this to enable support for saving memory data as a
1548 file in FAT formatted partition.
1550 This will also enable the command "fatwrite" enabling the
1551 user to write files to FAT.
1553 - CBFS (Coreboot Filesystem) support:
1556 Define this to enable support for reading from a Coreboot
1557 filesystem. Available commands are cbfsinit, cbfsinfo, cbfsls
1560 - FAT(File Allocation Table) filesystem cluster size:
1561 CONFIG_FS_FAT_MAX_CLUSTSIZE
1563 Define the max cluster size for fat operations else
1564 a default value of 65536 will be defined.
1567 See Kconfig help for available keyboard drivers.
1571 Define this to enable a custom keyboard support.
1572 This simply calls drv_keyboard_init() which must be
1573 defined in your board-specific files. This option is deprecated
1574 and is only used by novena. For new boards, use driver model
1579 Enable the Freescale DIU video driver. Reference boards for
1580 SOCs that have a DIU should define this macro to enable DIU
1581 support, and should also define these other macros:
1587 CONFIG_VIDEO_SW_CURSOR
1588 CONFIG_VGA_AS_SINGLE_DEVICE
1590 CONFIG_VIDEO_BMP_LOGO
1592 The DIU driver will look for the 'video-mode' environment
1593 variable, and if defined, enable the DIU as a console during
1594 boot. See the documentation file doc/README.video for a
1595 description of this variable.
1597 - LCD Support: CONFIG_LCD
1599 Define this to enable LCD support (for output to LCD
1600 display); also select one of the supported displays
1601 by defining one of these:
1605 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1607 CONFIG_NEC_NL6448AC33:
1609 NEC NL6448AC33-18. Active, color, single scan.
1611 CONFIG_NEC_NL6448BC20
1613 NEC NL6448BC20-08. 6.5", 640x480.
1614 Active, color, single scan.
1616 CONFIG_NEC_NL6448BC33_54
1618 NEC NL6448BC33-54. 10.4", 640x480.
1619 Active, color, single scan.
1623 Sharp 320x240. Active, color, single scan.
1624 It isn't 16x9, and I am not sure what it is.
1626 CONFIG_SHARP_LQ64D341
1628 Sharp LQ64D341 display, 640x480.
1629 Active, color, single scan.
1633 HLD1045 display, 640x480.
1634 Active, color, single scan.
1638 Optrex CBL50840-2 NF-FW 99 22 M5
1640 Hitachi LMG6912RPFC-00T
1644 320x240. Black & white.
1646 Normally display is black on white background; define
1647 CONFIG_SYS_WHITE_ON_BLACK to get it inverted.
1649 CONFIG_LCD_ALIGNMENT
1651 Normally the LCD is page-aligned (typically 4KB). If this is
1652 defined then the LCD will be aligned to this value instead.
1653 For ARM it is sometimes useful to use MMU_SECTION_SIZE
1654 here, since it is cheaper to change data cache settings on
1655 a per-section basis.
1660 Sometimes, for example if the display is mounted in portrait
1661 mode or even if it's mounted landscape but rotated by 180degree,
1662 we need to rotate our content of the display relative to the
1663 framebuffer, so that user can read the messages which are
1665 Once CONFIG_LCD_ROTATION is defined, the lcd_console will be
1666 initialized with a given rotation from "vl_rot" out of
1667 "vidinfo_t" which is provided by the board specific code.
1668 The value for vl_rot is coded as following (matching to
1669 fbcon=rotate:<n> linux-kernel commandline):
1670 0 = no rotation respectively 0 degree
1671 1 = 90 degree rotation
1672 2 = 180 degree rotation
1673 3 = 270 degree rotation
1675 If CONFIG_LCD_ROTATION is not defined, the console will be
1676 initialized with 0degree rotation.
1680 Support drawing of RLE8-compressed bitmaps on the LCD.
1684 Enables an 'i2c edid' command which can read EDID
1685 information over I2C from an attached LCD display.
1687 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1689 If this option is set, the environment is checked for
1690 a variable "splashimage". If found, the usual display
1691 of logo, copyright and system information on the LCD
1692 is suppressed and the BMP image at the address
1693 specified in "splashimage" is loaded instead. The
1694 console is redirected to the "nulldev", too. This
1695 allows for a "silent" boot where a splash screen is
1696 loaded very quickly after power-on.
1698 CONFIG_SPLASHIMAGE_GUARD
1700 If this option is set, then U-Boot will prevent the environment
1701 variable "splashimage" from being set to a problematic address
1702 (see doc/README.displaying-bmps).
1703 This option is useful for targets where, due to alignment
1704 restrictions, an improperly aligned BMP image will cause a data
1705 abort. If you think you will not have problems with unaligned
1706 accesses (for example because your toolchain prevents them)
1707 there is no need to set this option.
1709 CONFIG_SPLASH_SCREEN_ALIGN
1711 If this option is set the splash image can be freely positioned
1712 on the screen. Environment variable "splashpos" specifies the
1713 position as "x,y". If a positive number is given it is used as
1714 number of pixel from left/top. If a negative number is given it
1715 is used as number of pixel from right/bottom. You can also
1716 specify 'm' for centering the image.
1719 setenv splashpos m,m
1720 => image at center of screen
1722 setenv splashpos 30,20
1723 => image at x = 30 and y = 20
1725 setenv splashpos -10,m
1726 => vertically centered image
1727 at x = dspWidth - bmpWidth - 9
1729 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1731 If this option is set, additionally to standard BMP
1732 images, gzipped BMP images can be displayed via the
1733 splashscreen support or the bmp command.
1735 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1737 If this option is set, 8-bit RLE compressed BMP images
1738 can be displayed via the splashscreen support or the
1741 - Compression support:
1744 Enabled by default to support gzip compressed images.
1748 If this option is set, support for bzip2 compressed
1749 images is included. If not, only uncompressed and gzip
1750 compressed images are supported.
1752 NOTE: the bzip2 algorithm requires a lot of RAM, so
1753 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1758 If this option is set, support for lzma compressed
1761 Note: The LZMA algorithm adds between 2 and 4KB of code and it
1762 requires an amount of dynamic memory that is given by the
1765 (1846 + 768 << (lc + lp)) * sizeof(uint16)
1767 Where lc and lp stand for, respectively, Literal context bits
1768 and Literal pos bits.
1770 This value is upper-bounded by 14MB in the worst case. Anyway,
1771 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
1772 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
1773 a very small buffer.
1775 Use the lzmainfo tool to determinate the lc and lp values and
1776 then calculate the amount of needed dynamic memory (ensuring
1777 the appropriate CONFIG_SYS_MALLOC_LEN value).
1781 If this option is set, support for LZO compressed images
1787 The address of PHY on MII bus.
1789 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1791 The clock frequency of the MII bus
1795 If this option is set, support for speed/duplex
1796 detection of gigabit PHY is included.
1798 CONFIG_PHY_RESET_DELAY
1800 Some PHY like Intel LXT971A need extra delay after
1801 reset before any MII register access is possible.
1802 For such PHY, set this option to the usec delay
1803 required. (minimum 300usec for LXT971A)
1805 CONFIG_PHY_CMD_DELAY (ppc4xx)
1807 Some PHY like Intel LXT971A need extra delay after
1808 command issued before MII status register can be read
1813 Define a default value for the IP address to use for
1814 the default Ethernet interface, in case this is not
1815 determined through e.g. bootp.
1816 (Environment variable "ipaddr")
1818 - Server IP address:
1821 Defines a default value for the IP address of a TFTP
1822 server to contact when using the "tftboot" command.
1823 (Environment variable "serverip")
1825 CONFIG_KEEP_SERVERADDR
1827 Keeps the server's MAC address, in the env 'serveraddr'
1828 for passing to bootargs (like Linux's netconsole option)
1830 - Gateway IP address:
1833 Defines a default value for the IP address of the
1834 default router where packets to other networks are
1836 (Environment variable "gatewayip")
1841 Defines a default value for the subnet mask (or
1842 routing prefix) which is used to determine if an IP
1843 address belongs to the local subnet or needs to be
1844 forwarded through a router.
1845 (Environment variable "netmask")
1847 - Multicast TFTP Mode:
1850 Defines whether you want to support multicast TFTP as per
1851 rfc-2090; for example to work with atftp. Lets lots of targets
1852 tftp down the same boot image concurrently. Note: the Ethernet
1853 driver in use must provide a function: mcast() to join/leave a
1856 - BOOTP Recovery Mode:
1857 CONFIG_BOOTP_RANDOM_DELAY
1859 If you have many targets in a network that try to
1860 boot using BOOTP, you may want to avoid that all
1861 systems send out BOOTP requests at precisely the same
1862 moment (which would happen for instance at recovery
1863 from a power failure, when all systems will try to
1864 boot, thus flooding the BOOTP server. Defining
1865 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1866 inserted before sending out BOOTP requests. The
1867 following delays are inserted then:
1869 1st BOOTP request: delay 0 ... 1 sec
1870 2nd BOOTP request: delay 0 ... 2 sec
1871 3rd BOOTP request: delay 0 ... 4 sec
1873 BOOTP requests: delay 0 ... 8 sec
1875 CONFIG_BOOTP_ID_CACHE_SIZE
1877 BOOTP packets are uniquely identified using a 32-bit ID. The
1878 server will copy the ID from client requests to responses and
1879 U-Boot will use this to determine if it is the destination of
1880 an incoming response. Some servers will check that addresses
1881 aren't in use before handing them out (usually using an ARP
1882 ping) and therefore take up to a few hundred milliseconds to
1883 respond. Network congestion may also influence the time it
1884 takes for a response to make it back to the client. If that
1885 time is too long, U-Boot will retransmit requests. In order
1886 to allow earlier responses to still be accepted after these
1887 retransmissions, U-Boot's BOOTP client keeps a small cache of
1888 IDs. The CONFIG_BOOTP_ID_CACHE_SIZE controls the size of this
1889 cache. The default is to keep IDs for up to four outstanding
1890 requests. Increasing this will allow U-Boot to accept offers
1891 from a BOOTP client in networks with unusually high latency.
1893 - DHCP Advanced Options:
1894 You can fine tune the DHCP functionality by defining
1895 CONFIG_BOOTP_* symbols:
1897 CONFIG_BOOTP_SUBNETMASK
1898 CONFIG_BOOTP_GATEWAY
1899 CONFIG_BOOTP_HOSTNAME
1900 CONFIG_BOOTP_NISDOMAIN
1901 CONFIG_BOOTP_BOOTPATH
1902 CONFIG_BOOTP_BOOTFILESIZE
1905 CONFIG_BOOTP_SEND_HOSTNAME
1906 CONFIG_BOOTP_NTPSERVER
1907 CONFIG_BOOTP_TIMEOFFSET
1908 CONFIG_BOOTP_VENDOREX
1909 CONFIG_BOOTP_MAY_FAIL
1911 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1912 environment variable, not the BOOTP server.
1914 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
1915 after the configured retry count, the call will fail
1916 instead of starting over. This can be used to fail over
1917 to Link-local IP address configuration if the DHCP server
1920 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1921 serverip from a DHCP server, it is possible that more
1922 than one DNS serverip is offered to the client.
1923 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1924 serverip will be stored in the additional environment
1925 variable "dnsip2". The first DNS serverip is always
1926 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1929 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1930 to do a dynamic update of a DNS server. To do this, they
1931 need the hostname of the DHCP requester.
1932 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1933 of the "hostname" environment variable is passed as
1934 option 12 to the DHCP server.
1936 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1938 A 32bit value in microseconds for a delay between
1939 receiving a "DHCP Offer" and sending the "DHCP Request".
1940 This fixes a problem with certain DHCP servers that don't
1941 respond 100% of the time to a "DHCP request". E.g. On an
1942 AT91RM9200 processor running at 180MHz, this delay needed
1943 to be *at least* 15,000 usec before a Windows Server 2003
1944 DHCP server would reply 100% of the time. I recommend at
1945 least 50,000 usec to be safe. The alternative is to hope
1946 that one of the retries will be successful but note that
1947 the DHCP timeout and retry process takes a longer than
1950 - Link-local IP address negotiation:
1951 Negotiate with other link-local clients on the local network
1952 for an address that doesn't require explicit configuration.
1953 This is especially useful if a DHCP server cannot be guaranteed
1954 to exist in all environments that the device must operate.
1956 See doc/README.link-local for more information.
1959 CONFIG_CDP_DEVICE_ID
1961 The device id used in CDP trigger frames.
1963 CONFIG_CDP_DEVICE_ID_PREFIX
1965 A two character string which is prefixed to the MAC address
1970 A printf format string which contains the ascii name of
1971 the port. Normally is set to "eth%d" which sets
1972 eth0 for the first Ethernet, eth1 for the second etc.
1974 CONFIG_CDP_CAPABILITIES
1976 A 32bit integer which indicates the device capabilities;
1977 0x00000010 for a normal host which does not forwards.
1981 An ascii string containing the version of the software.
1985 An ascii string containing the name of the platform.
1989 A 32bit integer sent on the trigger.
1991 CONFIG_CDP_POWER_CONSUMPTION
1993 A 16bit integer containing the power consumption of the
1994 device in .1 of milliwatts.
1996 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1998 A byte containing the id of the VLAN.
2000 - Status LED: CONFIG_LED_STATUS
2002 Several configurations allow to display the current
2003 status using a LED. For instance, the LED will blink
2004 fast while running U-Boot code, stop blinking as
2005 soon as a reply to a BOOTP request was received, and
2006 start blinking slow once the Linux kernel is running
2007 (supported by a status LED driver in the Linux
2008 kernel). Defining CONFIG_LED_STATUS enables this
2013 CONFIG_LED_STATUS_GPIO
2014 The status LED can be connected to a GPIO pin.
2015 In such cases, the gpio_led driver can be used as a
2016 status LED backend implementation. Define CONFIG_LED_STATUS_GPIO
2017 to include the gpio_led driver in the U-Boot binary.
2019 CONFIG_GPIO_LED_INVERTED_TABLE
2020 Some GPIO connected LEDs may have inverted polarity in which
2021 case the GPIO high value corresponds to LED off state and
2022 GPIO low value corresponds to LED on state.
2023 In such cases CONFIG_GPIO_LED_INVERTED_TABLE may be defined
2024 with a list of GPIO LEDs that have inverted polarity.
2026 - CAN Support: CONFIG_CAN_DRIVER
2028 Defining CONFIG_CAN_DRIVER enables CAN driver support
2029 on those systems that support this (optional)
2030 feature, like the TQM8xxL modules.
2032 - I2C Support: CONFIG_SYS_I2C
2034 This enable the NEW i2c subsystem, and will allow you to use
2035 i2c commands at the u-boot command line (as long as you set
2036 CONFIG_CMD_I2C in CONFIG_COMMANDS) and communicate with i2c
2037 based realtime clock chips or other i2c devices. See
2038 common/cmd_i2c.c for a description of the command line
2041 ported i2c driver to the new framework:
2042 - drivers/i2c/soft_i2c.c:
2043 - activate first bus with CONFIG_SYS_I2C_SOFT define
2044 CONFIG_SYS_I2C_SOFT_SPEED and CONFIG_SYS_I2C_SOFT_SLAVE
2045 for defining speed and slave address
2046 - activate second bus with I2C_SOFT_DECLARATIONS2 define
2047 CONFIG_SYS_I2C_SOFT_SPEED_2 and CONFIG_SYS_I2C_SOFT_SLAVE_2
2048 for defining speed and slave address
2049 - activate third bus with I2C_SOFT_DECLARATIONS3 define
2050 CONFIG_SYS_I2C_SOFT_SPEED_3 and CONFIG_SYS_I2C_SOFT_SLAVE_3
2051 for defining speed and slave address
2052 - activate fourth bus with I2C_SOFT_DECLARATIONS4 define
2053 CONFIG_SYS_I2C_SOFT_SPEED_4 and CONFIG_SYS_I2C_SOFT_SLAVE_4
2054 for defining speed and slave address
2056 - drivers/i2c/fsl_i2c.c:
2057 - activate i2c driver with CONFIG_SYS_I2C_FSL
2058 define CONFIG_SYS_FSL_I2C_OFFSET for setting the register
2059 offset CONFIG_SYS_FSL_I2C_SPEED for the i2c speed and
2060 CONFIG_SYS_FSL_I2C_SLAVE for the slave addr of the first
2062 - If your board supports a second fsl i2c bus, define
2063 CONFIG_SYS_FSL_I2C2_OFFSET for the register offset
2064 CONFIG_SYS_FSL_I2C2_SPEED for the speed and
2065 CONFIG_SYS_FSL_I2C2_SLAVE for the slave address of the
2068 - drivers/i2c/tegra_i2c.c:
2069 - activate this driver with CONFIG_SYS_I2C_TEGRA
2070 - This driver adds 4 i2c buses with a fix speed from
2071 100000 and the slave addr 0!
2073 - drivers/i2c/ppc4xx_i2c.c
2074 - activate this driver with CONFIG_SYS_I2C_PPC4XX
2075 - CONFIG_SYS_I2C_PPC4XX_CH0 activate hardware channel 0
2076 - CONFIG_SYS_I2C_PPC4XX_CH1 activate hardware channel 1
2078 - drivers/i2c/i2c_mxc.c
2079 - activate this driver with CONFIG_SYS_I2C_MXC
2080 - enable bus 1 with CONFIG_SYS_I2C_MXC_I2C1
2081 - enable bus 2 with CONFIG_SYS_I2C_MXC_I2C2
2082 - enable bus 3 with CONFIG_SYS_I2C_MXC_I2C3
2083 - enable bus 4 with CONFIG_SYS_I2C_MXC_I2C4
2084 - define speed for bus 1 with CONFIG_SYS_MXC_I2C1_SPEED
2085 - define slave for bus 1 with CONFIG_SYS_MXC_I2C1_SLAVE
2086 - define speed for bus 2 with CONFIG_SYS_MXC_I2C2_SPEED
2087 - define slave for bus 2 with CONFIG_SYS_MXC_I2C2_SLAVE
2088 - define speed for bus 3 with CONFIG_SYS_MXC_I2C3_SPEED
2089 - define slave for bus 3 with CONFIG_SYS_MXC_I2C3_SLAVE
2090 - define speed for bus 4 with CONFIG_SYS_MXC_I2C4_SPEED
2091 - define slave for bus 4 with CONFIG_SYS_MXC_I2C4_SLAVE
2092 If those defines are not set, default value is 100000
2093 for speed, and 0 for slave.
2095 - drivers/i2c/rcar_i2c.c:
2096 - activate this driver with CONFIG_SYS_I2C_RCAR
2097 - This driver adds 4 i2c buses
2099 - CONFIG_SYS_RCAR_I2C0_BASE for setting the register channel 0
2100 - CONFIG_SYS_RCAR_I2C0_SPEED for for the speed channel 0
2101 - CONFIG_SYS_RCAR_I2C1_BASE for setting the register channel 1
2102 - CONFIG_SYS_RCAR_I2C1_SPEED for for the speed channel 1
2103 - CONFIG_SYS_RCAR_I2C2_BASE for setting the register channel 2
2104 - CONFIG_SYS_RCAR_I2C2_SPEED for for the speed channel 2
2105 - CONFIG_SYS_RCAR_I2C3_BASE for setting the register channel 3
2106 - CONFIG_SYS_RCAR_I2C3_SPEED for for the speed channel 3
2107 - CONFIF_SYS_RCAR_I2C_NUM_CONTROLLERS for number of i2c buses
2109 - drivers/i2c/sh_i2c.c:
2110 - activate this driver with CONFIG_SYS_I2C_SH
2111 - This driver adds from 2 to 5 i2c buses
2113 - CONFIG_SYS_I2C_SH_BASE0 for setting the register channel 0
2114 - CONFIG_SYS_I2C_SH_SPEED0 for for the speed channel 0
2115 - CONFIG_SYS_I2C_SH_BASE1 for setting the register channel 1
2116 - CONFIG_SYS_I2C_SH_SPEED1 for for the speed channel 1
2117 - CONFIG_SYS_I2C_SH_BASE2 for setting the register channel 2
2118 - CONFIG_SYS_I2C_SH_SPEED2 for for the speed channel 2
2119 - CONFIG_SYS_I2C_SH_BASE3 for setting the register channel 3
2120 - CONFIG_SYS_I2C_SH_SPEED3 for for the speed channel 3
2121 - CONFIG_SYS_I2C_SH_BASE4 for setting the register channel 4
2122 - CONFIG_SYS_I2C_SH_SPEED4 for for the speed channel 4
2123 - CONFIG_SYS_I2C_SH_NUM_CONTROLLERS for number of i2c buses
2125 - drivers/i2c/omap24xx_i2c.c
2126 - activate this driver with CONFIG_SYS_I2C_OMAP24XX
2127 - CONFIG_SYS_OMAP24_I2C_SPEED speed channel 0
2128 - CONFIG_SYS_OMAP24_I2C_SLAVE slave addr channel 0
2129 - CONFIG_SYS_OMAP24_I2C_SPEED1 speed channel 1
2130 - CONFIG_SYS_OMAP24_I2C_SLAVE1 slave addr channel 1
2131 - CONFIG_SYS_OMAP24_I2C_SPEED2 speed channel 2
2132 - CONFIG_SYS_OMAP24_I2C_SLAVE2 slave addr channel 2
2133 - CONFIG_SYS_OMAP24_I2C_SPEED3 speed channel 3
2134 - CONFIG_SYS_OMAP24_I2C_SLAVE3 slave addr channel 3
2135 - CONFIG_SYS_OMAP24_I2C_SPEED4 speed channel 4
2136 - CONFIG_SYS_OMAP24_I2C_SLAVE4 slave addr channel 4
2138 - drivers/i2c/zynq_i2c.c
2139 - activate this driver with CONFIG_SYS_I2C_ZYNQ
2140 - set CONFIG_SYS_I2C_ZYNQ_SPEED for speed setting
2141 - set CONFIG_SYS_I2C_ZYNQ_SLAVE for slave addr
2143 - drivers/i2c/s3c24x0_i2c.c:
2144 - activate this driver with CONFIG_SYS_I2C_S3C24X0
2145 - This driver adds i2c buses (11 for Exynos5250, Exynos5420
2146 9 i2c buses for Exynos4 and 1 for S3C24X0 SoCs from Samsung)
2147 with a fix speed from 100000 and the slave addr 0!
2149 - drivers/i2c/ihs_i2c.c
2150 - activate this driver with CONFIG_SYS_I2C_IHS
2151 - CONFIG_SYS_I2C_IHS_CH0 activate hardware channel 0
2152 - CONFIG_SYS_I2C_IHS_SPEED_0 speed channel 0
2153 - CONFIG_SYS_I2C_IHS_SLAVE_0 slave addr channel 0
2154 - CONFIG_SYS_I2C_IHS_CH1 activate hardware channel 1
2155 - CONFIG_SYS_I2C_IHS_SPEED_1 speed channel 1
2156 - CONFIG_SYS_I2C_IHS_SLAVE_1 slave addr channel 1
2157 - CONFIG_SYS_I2C_IHS_CH2 activate hardware channel 2
2158 - CONFIG_SYS_I2C_IHS_SPEED_2 speed channel 2
2159 - CONFIG_SYS_I2C_IHS_SLAVE_2 slave addr channel 2
2160 - CONFIG_SYS_I2C_IHS_CH3 activate hardware channel 3
2161 - CONFIG_SYS_I2C_IHS_SPEED_3 speed channel 3
2162 - CONFIG_SYS_I2C_IHS_SLAVE_3 slave addr channel 3
2163 - activate dual channel with CONFIG_SYS_I2C_IHS_DUAL
2164 - CONFIG_SYS_I2C_IHS_SPEED_0_1 speed channel 0_1
2165 - CONFIG_SYS_I2C_IHS_SLAVE_0_1 slave addr channel 0_1
2166 - CONFIG_SYS_I2C_IHS_SPEED_1_1 speed channel 1_1
2167 - CONFIG_SYS_I2C_IHS_SLAVE_1_1 slave addr channel 1_1
2168 - CONFIG_SYS_I2C_IHS_SPEED_2_1 speed channel 2_1
2169 - CONFIG_SYS_I2C_IHS_SLAVE_2_1 slave addr channel 2_1
2170 - CONFIG_SYS_I2C_IHS_SPEED_3_1 speed channel 3_1
2171 - CONFIG_SYS_I2C_IHS_SLAVE_3_1 slave addr channel 3_1
2175 CONFIG_SYS_NUM_I2C_BUSES
2176 Hold the number of i2c buses you want to use.
2178 CONFIG_SYS_I2C_DIRECT_BUS
2179 define this, if you don't use i2c muxes on your hardware.
2180 if CONFIG_SYS_I2C_MAX_HOPS is not defined or == 0 you can
2183 CONFIG_SYS_I2C_MAX_HOPS
2184 define how many muxes are maximal consecutively connected
2185 on one i2c bus. If you not use i2c muxes, omit this
2188 CONFIG_SYS_I2C_BUSES
2189 hold a list of buses you want to use, only used if
2190 CONFIG_SYS_I2C_DIRECT_BUS is not defined, for example
2191 a board with CONFIG_SYS_I2C_MAX_HOPS = 1 and
2192 CONFIG_SYS_NUM_I2C_BUSES = 9:
2194 CONFIG_SYS_I2C_BUSES {{0, {I2C_NULL_HOP}}, \
2195 {0, {{I2C_MUX_PCA9547, 0x70, 1}}}, \
2196 {0, {{I2C_MUX_PCA9547, 0x70, 2}}}, \
2197 {0, {{I2C_MUX_PCA9547, 0x70, 3}}}, \
2198 {0, {{I2C_MUX_PCA9547, 0x70, 4}}}, \
2199 {0, {{I2C_MUX_PCA9547, 0x70, 5}}}, \
2200 {1, {I2C_NULL_HOP}}, \
2201 {1, {{I2C_MUX_PCA9544, 0x72, 1}}}, \
2202 {1, {{I2C_MUX_PCA9544, 0x72, 2}}}, \
2206 bus 0 on adapter 0 without a mux
2207 bus 1 on adapter 0 with a PCA9547 on address 0x70 port 1
2208 bus 2 on adapter 0 with a PCA9547 on address 0x70 port 2
2209 bus 3 on adapter 0 with a PCA9547 on address 0x70 port 3
2210 bus 4 on adapter 0 with a PCA9547 on address 0x70 port 4
2211 bus 5 on adapter 0 with a PCA9547 on address 0x70 port 5
2212 bus 6 on adapter 1 without a mux
2213 bus 7 on adapter 1 with a PCA9544 on address 0x72 port 1
2214 bus 8 on adapter 1 with a PCA9544 on address 0x72 port 2
2216 If you do not have i2c muxes on your board, omit this define.
2218 - Legacy I2C Support: CONFIG_HARD_I2C
2220 NOTE: It is intended to move drivers to CONFIG_SYS_I2C which
2221 provides the following compelling advantages:
2223 - more than one i2c adapter is usable
2224 - approved multibus support
2225 - better i2c mux support
2227 ** Please consider updating your I2C driver now. **
2229 These enable legacy I2C serial bus commands. Defining
2230 CONFIG_HARD_I2C will include the appropriate I2C driver
2231 for the selected CPU.
2233 This will allow you to use i2c commands at the u-boot
2234 command line (as long as you set CONFIG_CMD_I2C in
2235 CONFIG_COMMANDS) and communicate with i2c based realtime
2236 clock chips. See common/cmd_i2c.c for a description of the
2237 command line interface.
2239 CONFIG_HARD_I2C selects a hardware I2C controller.
2241 There are several other quantities that must also be
2242 defined when you define CONFIG_HARD_I2C.
2244 In both cases you will need to define CONFIG_SYS_I2C_SPEED
2245 to be the frequency (in Hz) at which you wish your i2c bus
2246 to run and CONFIG_SYS_I2C_SLAVE to be the address of this node (ie
2247 the CPU's i2c node address).
2249 Now, the u-boot i2c code for the mpc8xx
2250 (arch/powerpc/cpu/mpc8xx/i2c.c) sets the CPU up as a master node
2251 and so its address should therefore be cleared to 0 (See,
2252 eg, MPC823e User's Manual p.16-473). So, set
2253 CONFIG_SYS_I2C_SLAVE to 0.
2255 CONFIG_SYS_I2C_INIT_MPC5XXX
2257 When a board is reset during an i2c bus transfer
2258 chips might think that the current transfer is still
2259 in progress. Reset the slave devices by sending start
2260 commands until the slave device responds.
2262 That's all that's required for CONFIG_HARD_I2C.
2264 If you use the software i2c interface (CONFIG_SYS_I2C_SOFT)
2265 then the following macros need to be defined (examples are
2266 from include/configs/lwmon.h):
2270 (Optional). Any commands necessary to enable the I2C
2271 controller or configure ports.
2273 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
2277 (Only for MPC8260 CPU). The I/O port to use (the code
2278 assumes both bits are on the same port). Valid values
2279 are 0..3 for ports A..D.
2283 The code necessary to make the I2C data line active
2284 (driven). If the data line is open collector, this
2287 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
2291 The code necessary to make the I2C data line tri-stated
2292 (inactive). If the data line is open collector, this
2295 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
2299 Code that returns true if the I2C data line is high,
2302 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
2306 If <bit> is true, sets the I2C data line high. If it
2307 is false, it clears it (low).
2309 eg: #define I2C_SDA(bit) \
2310 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
2311 else immr->im_cpm.cp_pbdat &= ~PB_SDA
2315 If <bit> is true, sets the I2C clock line high. If it
2316 is false, it clears it (low).
2318 eg: #define I2C_SCL(bit) \
2319 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
2320 else immr->im_cpm.cp_pbdat &= ~PB_SCL
2324 This delay is invoked four times per clock cycle so this
2325 controls the rate of data transfer. The data rate thus
2326 is 1 / (I2C_DELAY * 4). Often defined to be something
2329 #define I2C_DELAY udelay(2)
2331 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
2333 If your arch supports the generic GPIO framework (asm/gpio.h),
2334 then you may alternatively define the two GPIOs that are to be
2335 used as SCL / SDA. Any of the previous I2C_xxx macros will
2336 have GPIO-based defaults assigned to them as appropriate.
2338 You should define these to the GPIO value as given directly to
2339 the generic GPIO functions.
2341 CONFIG_SYS_I2C_INIT_BOARD
2343 When a board is reset during an i2c bus transfer
2344 chips might think that the current transfer is still
2345 in progress. On some boards it is possible to access
2346 the i2c SCLK line directly, either by using the
2347 processor pin as a GPIO or by having a second pin
2348 connected to the bus. If this option is defined a
2349 custom i2c_init_board() routine in boards/xxx/board.c
2350 is run early in the boot sequence.
2352 CONFIG_SYS_I2C_BOARD_LATE_INIT
2354 An alternative to CONFIG_SYS_I2C_INIT_BOARD. If this option is
2355 defined a custom i2c_board_late_init() routine in
2356 boards/xxx/board.c is run AFTER the operations in i2c_init()
2357 is completed. This callpoint can be used to unreset i2c bus
2358 using CPU i2c controller register accesses for CPUs whose i2c
2359 controller provide such a method. It is called at the end of
2360 i2c_init() to allow i2c_init operations to setup the i2c bus
2361 controller on the CPU (e.g. setting bus speed & slave address).
2363 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
2365 This option enables configuration of bi_iic_fast[] flags
2366 in u-boot bd_info structure based on u-boot environment
2367 variable "i2cfast". (see also i2cfast)
2369 CONFIG_I2C_MULTI_BUS
2371 This option allows the use of multiple I2C buses, each of which
2372 must have a controller. At any point in time, only one bus is
2373 active. To switch to a different bus, use the 'i2c dev' command.
2374 Note that bus numbering is zero-based.
2376 CONFIG_SYS_I2C_NOPROBES
2378 This option specifies a list of I2C devices that will be skipped
2379 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
2380 is set, specify a list of bus-device pairs. Otherwise, specify
2381 a 1D array of device addresses
2384 #undef CONFIG_I2C_MULTI_BUS
2385 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
2387 will skip addresses 0x50 and 0x68 on a board with one I2C bus
2389 #define CONFIG_I2C_MULTI_BUS
2390 #define CONFIG_SYS_I2C_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
2392 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
2394 CONFIG_SYS_SPD_BUS_NUM
2396 If defined, then this indicates the I2C bus number for DDR SPD.
2397 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
2399 CONFIG_SYS_RTC_BUS_NUM
2401 If defined, then this indicates the I2C bus number for the RTC.
2402 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
2404 CONFIG_SYS_DTT_BUS_NUM
2406 If defined, then this indicates the I2C bus number for the DTT.
2407 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
2409 CONFIG_SYS_I2C_DTT_ADDR:
2411 If defined, specifies the I2C address of the DTT device.
2412 If not defined, then U-Boot uses predefined value for
2413 specified DTT device.
2415 CONFIG_SOFT_I2C_READ_REPEATED_START
2417 defining this will force the i2c_read() function in
2418 the soft_i2c driver to perform an I2C repeated start
2419 between writing the address pointer and reading the
2420 data. If this define is omitted the default behaviour
2421 of doing a stop-start sequence will be used. Most I2C
2422 devices can use either method, but some require one or
2425 - SPI Support: CONFIG_SPI
2427 Enables SPI driver (so far only tested with
2428 SPI EEPROM, also an instance works with Crystal A/D and
2429 D/As on the SACSng board)
2433 Enables the driver for SPI controller on SuperH. Currently
2434 only SH7757 is supported.
2438 Enables a software (bit-bang) SPI driver rather than
2439 using hardware support. This is a general purpose
2440 driver that only requires three general I/O port pins
2441 (two outputs, one input) to function. If this is
2442 defined, the board configuration must define several
2443 SPI configuration items (port pins to use, etc). For
2444 an example, see include/configs/sacsng.h.
2448 Enables a hardware SPI driver for general-purpose reads
2449 and writes. As with CONFIG_SOFT_SPI, the board configuration
2450 must define a list of chip-select function pointers.
2451 Currently supported on some MPC8xxx processors. For an
2452 example, see include/configs/mpc8349emds.h.
2456 Enables the driver for the SPI controllers on i.MX and MXC
2457 SoCs. Currently i.MX31/35/51 are supported.
2459 CONFIG_SYS_SPI_MXC_WAIT
2460 Timeout for waiting until spi transfer completed.
2461 default: (CONFIG_SYS_HZ/100) /* 10 ms */
2463 - FPGA Support: CONFIG_FPGA
2465 Enables FPGA subsystem.
2467 CONFIG_FPGA_<vendor>
2469 Enables support for specific chip vendors.
2472 CONFIG_FPGA_<family>
2474 Enables support for FPGA family.
2475 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
2479 Specify the number of FPGA devices to support.
2481 CONFIG_CMD_FPGA_LOADMK
2483 Enable support for fpga loadmk command
2485 CONFIG_CMD_FPGA_LOADP
2487 Enable support for fpga loadp command - load partial bitstream
2489 CONFIG_CMD_FPGA_LOADBP
2491 Enable support for fpga loadbp command - load partial bitstream
2494 CONFIG_SYS_FPGA_PROG_FEEDBACK
2496 Enable printing of hash marks during FPGA configuration.
2498 CONFIG_SYS_FPGA_CHECK_BUSY
2500 Enable checks on FPGA configuration interface busy
2501 status by the configuration function. This option
2502 will require a board or device specific function to
2507 If defined, a function that provides delays in the FPGA
2508 configuration driver.
2510 CONFIG_SYS_FPGA_CHECK_CTRLC
2511 Allow Control-C to interrupt FPGA configuration
2513 CONFIG_SYS_FPGA_CHECK_ERROR
2515 Check for configuration errors during FPGA bitfile
2516 loading. For example, abort during Virtex II
2517 configuration if the INIT_B line goes low (which
2518 indicated a CRC error).
2520 CONFIG_SYS_FPGA_WAIT_INIT
2522 Maximum time to wait for the INIT_B line to de-assert
2523 after PROB_B has been de-asserted during a Virtex II
2524 FPGA configuration sequence. The default time is 500
2527 CONFIG_SYS_FPGA_WAIT_BUSY
2529 Maximum time to wait for BUSY to de-assert during
2530 Virtex II FPGA configuration. The default is 5 ms.
2532 CONFIG_SYS_FPGA_WAIT_CONFIG
2534 Time to wait after FPGA configuration. The default is
2537 - Configuration Management:
2540 Some SoCs need special image types (e.g. U-Boot binary
2541 with a special header) as build targets. By defining
2542 CONFIG_BUILD_TARGET in the SoC / board header, this
2543 special image will be automatically built upon calling
2548 If defined, this string will be added to the U-Boot
2549 version information (U_BOOT_VERSION)
2551 - Vendor Parameter Protection:
2553 U-Boot considers the values of the environment
2554 variables "serial#" (Board Serial Number) and
2555 "ethaddr" (Ethernet Address) to be parameters that
2556 are set once by the board vendor / manufacturer, and
2557 protects these variables from casual modification by
2558 the user. Once set, these variables are read-only,
2559 and write or delete attempts are rejected. You can
2560 change this behaviour:
2562 If CONFIG_ENV_OVERWRITE is #defined in your config
2563 file, the write protection for vendor parameters is
2564 completely disabled. Anybody can change or delete
2567 Alternatively, if you define _both_ an ethaddr in the
2568 default env _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2569 Ethernet address is installed in the environment,
2570 which can be changed exactly ONCE by the user. [The
2571 serial# is unaffected by this, i. e. it remains
2574 The same can be accomplished in a more flexible way
2575 for any variable by configuring the type of access
2576 to allow for those variables in the ".flags" variable
2577 or define CONFIG_ENV_FLAGS_LIST_STATIC.
2582 Define this variable to enable the reservation of
2583 "protected RAM", i. e. RAM which is not overwritten
2584 by U-Boot. Define CONFIG_PRAM to hold the number of
2585 kB you want to reserve for pRAM. You can overwrite
2586 this default value by defining an environment
2587 variable "pram" to the number of kB you want to
2588 reserve. Note that the board info structure will
2589 still show the full amount of RAM. If pRAM is
2590 reserved, a new environment variable "mem" will
2591 automatically be defined to hold the amount of
2592 remaining RAM in a form that can be passed as boot
2593 argument to Linux, for instance like that:
2595 setenv bootargs ... mem=\${mem}
2598 This way you can tell Linux not to use this memory,
2599 either, which results in a memory region that will
2600 not be affected by reboots.
2602 *WARNING* If your board configuration uses automatic
2603 detection of the RAM size, you must make sure that
2604 this memory test is non-destructive. So far, the
2605 following board configurations are known to be
2608 IVMS8, IVML24, SPD8xx, TQM8xxL,
2609 HERMES, IP860, RPXlite, LWMON,
2612 - Access to physical memory region (> 4GB)
2613 Some basic support is provided for operations on memory not
2614 normally accessible to U-Boot - e.g. some architectures
2615 support access to more than 4GB of memory on 32-bit
2616 machines using physical address extension or similar.
2617 Define CONFIG_PHYSMEM to access this basic support, which
2618 currently only supports clearing the memory.
2623 Define this variable to stop the system in case of a
2624 fatal error, so that you have to reset it manually.
2625 This is probably NOT a good idea for an embedded
2626 system where you want the system to reboot
2627 automatically as fast as possible, but it may be
2628 useful during development since you can try to debug
2629 the conditions that lead to the situation.
2631 CONFIG_NET_RETRY_COUNT
2633 This variable defines the number of retries for
2634 network operations like ARP, RARP, TFTP, or BOOTP
2635 before giving up the operation. If not defined, a
2636 default value of 5 is used.
2640 Timeout waiting for an ARP reply in milliseconds.
2644 Timeout in milliseconds used in NFS protocol.
2645 If you encounter "ERROR: Cannot umount" in nfs command,
2646 try longer timeout such as
2647 #define CONFIG_NFS_TIMEOUT 10000UL
2649 - Command Interpreter:
2650 CONFIG_AUTO_COMPLETE
2652 Enable auto completion of commands using TAB.
2654 CONFIG_SYS_PROMPT_HUSH_PS2
2656 This defines the secondary prompt string, which is
2657 printed when the command interpreter needs more input
2658 to complete a command. Usually "> ".
2662 In the current implementation, the local variables
2663 space and global environment variables space are
2664 separated. Local variables are those you define by
2665 simply typing `name=value'. To access a local
2666 variable later on, you have write `$name' or
2667 `${name}'; to execute the contents of a variable
2668 directly type `$name' at the command prompt.
2670 Global environment variables are those you use
2671 setenv/printenv to work with. To run a command stored
2672 in such a variable, you need to use the run command,
2673 and you must not use the '$' sign to access them.
2675 To store commands and special characters in a
2676 variable, please use double quotation marks
2677 surrounding the whole text of the variable, instead
2678 of the backslashes before semicolons and special
2681 - Command Line Editing and History:
2682 CONFIG_CMDLINE_EDITING
2684 Enable editing and History functions for interactive
2685 command line input operations
2687 - Command Line PS1/PS2 support:
2688 CONFIG_CMDLINE_PS_SUPPORT
2690 Enable support for changing the command prompt string
2691 at run-time. Only static string is supported so far.
2692 The string is obtained from environment variables PS1
2695 - Default Environment:
2696 CONFIG_EXTRA_ENV_SETTINGS
2698 Define this to contain any number of null terminated
2699 strings (variable = value pairs) that will be part of
2700 the default environment compiled into the boot image.
2702 For example, place something like this in your
2703 board's config file:
2705 #define CONFIG_EXTRA_ENV_SETTINGS \
2709 Warning: This method is based on knowledge about the
2710 internal format how the environment is stored by the
2711 U-Boot code. This is NOT an official, exported
2712 interface! Although it is unlikely that this format
2713 will change soon, there is no guarantee either.
2714 You better know what you are doing here.
2716 Note: overly (ab)use of the default environment is
2717 discouraged. Make sure to check other ways to preset
2718 the environment like the "source" command or the
2721 CONFIG_ENV_VARS_UBOOT_CONFIG
2723 Define this in order to add variables describing the
2724 U-Boot build configuration to the default environment.
2725 These will be named arch, cpu, board, vendor, and soc.
2727 Enabling this option will cause the following to be defined:
2735 CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG
2737 Define this in order to add variables describing certain
2738 run-time determined information about the hardware to the
2739 environment. These will be named board_name, board_rev.
2741 CONFIG_DELAY_ENVIRONMENT
2743 Normally the environment is loaded when the board is
2744 initialised so that it is available to U-Boot. This inhibits
2745 that so that the environment is not available until
2746 explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL
2747 this is instead controlled by the value of
2748 /config/load-environment.
2750 - DataFlash Support:
2751 CONFIG_HAS_DATAFLASH
2753 Defining this option enables DataFlash features and
2754 allows to read/write in Dataflash via the standard
2757 - Serial Flash support
2760 Defining this option enables SPI flash commands
2761 'sf probe/read/write/erase/update'.
2763 Usage requires an initial 'probe' to define the serial
2764 flash parameters, followed by read/write/erase/update
2767 The following defaults may be provided by the platform
2768 to handle the common case when only a single serial
2769 flash is present on the system.
2771 CONFIG_SF_DEFAULT_BUS Bus identifier
2772 CONFIG_SF_DEFAULT_CS Chip-select
2773 CONFIG_SF_DEFAULT_MODE (see include/spi.h)
2774 CONFIG_SF_DEFAULT_SPEED in Hz
2778 Define this option to include a destructive SPI flash
2781 CONFIG_SF_DUAL_FLASH Dual flash memories
2783 Define this option to use dual flash support where two flash
2784 memories can be connected with a given cs line.
2785 Currently Xilinx Zynq qspi supports these type of connections.
2787 - SystemACE Support:
2790 Adding this option adds support for Xilinx SystemACE
2791 chips attached via some sort of local bus. The address
2792 of the chip must also be defined in the
2793 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
2795 #define CONFIG_SYSTEMACE
2796 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
2798 When SystemACE support is added, the "ace" device type
2799 becomes available to the fat commands, i.e. fatls.
2801 - TFTP Fixed UDP Port:
2804 If this is defined, the environment variable tftpsrcp
2805 is used to supply the TFTP UDP source port value.
2806 If tftpsrcp isn't defined, the normal pseudo-random port
2807 number generator is used.
2809 Also, the environment variable tftpdstp is used to supply
2810 the TFTP UDP destination port value. If tftpdstp isn't
2811 defined, the normal port 69 is used.
2813 The purpose for tftpsrcp is to allow a TFTP server to
2814 blindly start the TFTP transfer using the pre-configured
2815 target IP address and UDP port. This has the effect of
2816 "punching through" the (Windows XP) firewall, allowing
2817 the remainder of the TFTP transfer to proceed normally.
2818 A better solution is to properly configure the firewall,
2819 but sometimes that is not allowed.
2824 This enables a generic 'hash' command which can produce
2825 hashes / digests from a few algorithms (e.g. SHA1, SHA256).
2829 Enable the hash verify command (hash -v). This adds to code
2832 CONFIG_SHA1 - This option enables support of hashing using SHA1
2833 algorithm. The hash is calculated in software.
2834 CONFIG_SHA256 - This option enables support of hashing using
2835 SHA256 algorithm. The hash is calculated in software.
2836 CONFIG_SHA_HW_ACCEL - This option enables hardware acceleration
2837 for SHA1/SHA256 hashing.
2838 This affects the 'hash' command and also the
2839 hash_lookup_algo() function.
2840 CONFIG_SHA_PROG_HW_ACCEL - This option enables
2841 hardware-acceleration for SHA1/SHA256 progressive hashing.
2842 Data can be streamed in a block at a time and the hashing
2843 is performed in hardware.
2845 Note: There is also a sha1sum command, which should perhaps
2846 be deprecated in favour of 'hash sha1'.
2848 - Freescale i.MX specific commands:
2849 CONFIG_CMD_HDMIDETECT
2850 This enables 'hdmidet' command which returns true if an
2851 HDMI monitor is detected. This command is i.MX 6 specific.
2854 This enables the 'bmode' (bootmode) command for forcing
2855 a boot from specific media.
2857 This is useful for forcing the ROM's usb downloader to
2858 activate upon a watchdog reset which is nice when iterating
2859 on U-Boot. Using the reset button or running bmode normal
2860 will set it back to normal. This command currently
2861 supports i.MX53 and i.MX6.
2863 - bootcount support:
2864 CONFIG_BOOTCOUNT_LIMIT
2866 This enables the bootcounter support, see:
2867 http://www.denx.de/wiki/DULG/UBootBootCountLimit
2870 enable special bootcounter support on at91sam9xe based boards.
2872 enable special bootcounter support on da850 based boards.
2873 CONFIG_BOOTCOUNT_RAM
2874 enable support for the bootcounter in RAM
2875 CONFIG_BOOTCOUNT_I2C
2876 enable support for the bootcounter on an i2c (like RTC) device.
2877 CONFIG_SYS_I2C_RTC_ADDR = i2c chip address
2878 CONFIG_SYS_BOOTCOUNT_ADDR = i2c addr which is used for
2880 CONFIG_BOOTCOUNT_ALEN = address len
2882 - Show boot progress:
2883 CONFIG_SHOW_BOOT_PROGRESS
2885 Defining this option allows to add some board-
2886 specific code (calling a user-provided function
2887 "show_boot_progress(int)") that enables you to show
2888 the system's boot progress on some display (for
2889 example, some LED's) on your board. At the moment,
2890 the following checkpoints are implemented:
2893 Legacy uImage format:
2896 1 common/cmd_bootm.c before attempting to boot an image
2897 -1 common/cmd_bootm.c Image header has bad magic number
2898 2 common/cmd_bootm.c Image header has correct magic number
2899 -2 common/cmd_bootm.c Image header has bad checksum
2900 3 common/cmd_bootm.c Image header has correct checksum
2901 -3 common/cmd_bootm.c Image data has bad checksum
2902 4 common/cmd_bootm.c Image data has correct checksum
2903 -4 common/cmd_bootm.c Image is for unsupported architecture
2904 5 common/cmd_bootm.c Architecture check OK
2905 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
2906 6 common/cmd_bootm.c Image Type check OK
2907 -6 common/cmd_bootm.c gunzip uncompression error
2908 -7 common/cmd_bootm.c Unimplemented compression type
2909 7 common/cmd_bootm.c Uncompression OK
2910 8 common/cmd_bootm.c No uncompress/copy overwrite error
2911 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
2913 9 common/image.c Start initial ramdisk verification
2914 -10 common/image.c Ramdisk header has bad magic number
2915 -11 common/image.c Ramdisk header has bad checksum
2916 10 common/image.c Ramdisk header is OK
2917 -12 common/image.c Ramdisk data has bad checksum
2918 11 common/image.c Ramdisk data has correct checksum
2919 12 common/image.c Ramdisk verification complete, start loading
2920 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
2921 13 common/image.c Start multifile image verification
2922 14 common/image.c No initial ramdisk, no multifile, continue.
2924 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
2926 -30 arch/powerpc/lib/board.c Fatal error, hang the system
2927 -31 post/post.c POST test failed, detected by post_output_backlog()
2928 -32 post/post.c POST test failed, detected by post_run_single()
2930 34 common/cmd_doc.c before loading a Image from a DOC device
2931 -35 common/cmd_doc.c Bad usage of "doc" command
2932 35 common/cmd_doc.c correct usage of "doc" command
2933 -36 common/cmd_doc.c No boot device
2934 36 common/cmd_doc.c correct boot device
2935 -37 common/cmd_doc.c Unknown Chip ID on boot device
2936 37 common/cmd_doc.c correct chip ID found, device available
2937 -38 common/cmd_doc.c Read Error on boot device
2938 38 common/cmd_doc.c reading Image header from DOC device OK
2939 -39 common/cmd_doc.c Image header has bad magic number
2940 39 common/cmd_doc.c Image header has correct magic number
2941 -40 common/cmd_doc.c Error reading Image from DOC device
2942 40 common/cmd_doc.c Image header has correct magic number
2943 41 common/cmd_ide.c before loading a Image from a IDE device
2944 -42 common/cmd_ide.c Bad usage of "ide" command
2945 42 common/cmd_ide.c correct usage of "ide" command
2946 -43 common/cmd_ide.c No boot device
2947 43 common/cmd_ide.c boot device found
2948 -44 common/cmd_ide.c Device not available
2949 44 common/cmd_ide.c Device available
2950 -45 common/cmd_ide.c wrong partition selected
2951 45 common/cmd_ide.c partition selected
2952 -46 common/cmd_ide.c Unknown partition table
2953 46 common/cmd_ide.c valid partition table found
2954 -47 common/cmd_ide.c Invalid partition type
2955 47 common/cmd_ide.c correct partition type
2956 -48 common/cmd_ide.c Error reading Image Header on boot device
2957 48 common/cmd_ide.c reading Image Header from IDE device OK
2958 -49 common/cmd_ide.c Image header has bad magic number
2959 49 common/cmd_ide.c Image header has correct magic number
2960 -50 common/cmd_ide.c Image header has bad checksum
2961 50 common/cmd_ide.c Image header has correct checksum
2962 -51 common/cmd_ide.c Error reading Image from IDE device
2963 51 common/cmd_ide.c reading Image from IDE device OK
2964 52 common/cmd_nand.c before loading a Image from a NAND device
2965 -53 common/cmd_nand.c Bad usage of "nand" command
2966 53 common/cmd_nand.c correct usage of "nand" command
2967 -54 common/cmd_nand.c No boot device
2968 54 common/cmd_nand.c boot device found
2969 -55 common/cmd_nand.c Unknown Chip ID on boot device
2970 55 common/cmd_nand.c correct chip ID found, device available
2971 -56 common/cmd_nand.c Error reading Image Header on boot device
2972 56 common/cmd_nand.c reading Image Header from NAND device OK
2973 -57 common/cmd_nand.c Image header has bad magic number
2974 57 common/cmd_nand.c Image header has correct magic number
2975 -58 common/cmd_nand.c Error reading Image from NAND device
2976 58 common/cmd_nand.c reading Image from NAND device OK
2978 -60 common/env_common.c Environment has a bad CRC, using default
2980 64 net/eth.c starting with Ethernet configuration.
2981 -64 net/eth.c no Ethernet found.
2982 65 net/eth.c Ethernet found.
2984 -80 common/cmd_net.c usage wrong
2985 80 common/cmd_net.c before calling net_loop()
2986 -81 common/cmd_net.c some error in net_loop() occurred
2987 81 common/cmd_net.c net_loop() back without error
2988 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
2989 82 common/cmd_net.c trying automatic boot
2990 83 common/cmd_net.c running "source" command
2991 -83 common/cmd_net.c some error in automatic boot or "source" command
2992 84 common/cmd_net.c end without errors
2997 100 common/cmd_bootm.c Kernel FIT Image has correct format
2998 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
2999 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
3000 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
3001 102 common/cmd_bootm.c Kernel unit name specified
3002 -103 common/cmd_bootm.c Can't get kernel subimage node offset
3003 103 common/cmd_bootm.c Found configuration node
3004 104 common/cmd_bootm.c Got kernel subimage node offset
3005 -104 common/cmd_bootm.c Kernel subimage hash verification failed
3006 105 common/cmd_bootm.c Kernel subimage hash verification OK
3007 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
3008 106 common/cmd_bootm.c Architecture check OK
3009 -106 common/cmd_bootm.c Kernel subimage has wrong type
3010 107 common/cmd_bootm.c Kernel subimage type OK
3011 -107 common/cmd_bootm.c Can't get kernel subimage data/size
3012 108 common/cmd_bootm.c Got kernel subimage data/size
3013 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
3014 -109 common/cmd_bootm.c Can't get kernel subimage type
3015 -110 common/cmd_bootm.c Can't get kernel subimage comp
3016 -111 common/cmd_bootm.c Can't get kernel subimage os
3017 -112 common/cmd_bootm.c Can't get kernel subimage load address
3018 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
3020 120 common/image.c Start initial ramdisk verification
3021 -120 common/image.c Ramdisk FIT image has incorrect format
3022 121 common/image.c Ramdisk FIT image has correct format
3023 122 common/image.c No ramdisk subimage unit name, using configuration
3024 -122 common/image.c Can't get configuration for ramdisk subimage
3025 123 common/image.c Ramdisk unit name specified
3026 -124 common/image.c Can't get ramdisk subimage node offset
3027 125 common/image.c Got ramdisk subimage node offset
3028 -125 common/image.c Ramdisk subimage hash verification failed
3029 126 common/image.c Ramdisk subimage hash verification OK
3030 -126 common/image.c Ramdisk subimage for unsupported architecture
3031 127 common/image.c Architecture check OK
3032 -127 common/image.c Can't get ramdisk subimage data/size
3033 128 common/image.c Got ramdisk subimage data/size
3034 129 common/image.c Can't get ramdisk load address
3035 -129 common/image.c Got ramdisk load address
3037 -130 common/cmd_doc.c Incorrect FIT image format
3038 131 common/cmd_doc.c FIT image format OK
3040 -140 common/cmd_ide.c Incorrect FIT image format
3041 141 common/cmd_ide.c FIT image format OK
3043 -150 common/cmd_nand.c Incorrect FIT image format
3044 151 common/cmd_nand.c FIT image format OK
3046 - legacy image format:
3047 CONFIG_IMAGE_FORMAT_LEGACY
3048 enables the legacy image format support in U-Boot.
3051 enabled if CONFIG_FIT_SIGNATURE is not defined.
3053 CONFIG_DISABLE_IMAGE_LEGACY
3054 disable the legacy image format
3056 This define is introduced, as the legacy image format is
3057 enabled per default for backward compatibility.
3059 - FIT image support:
3060 CONFIG_FIT_DISABLE_SHA256
3061 Supporting SHA256 hashes has quite an impact on binary size.
3062 For constrained systems sha256 hash support can be disabled
3065 TODO(sjg@chromium.org): Adjust this option to be positive,
3066 and move it to Kconfig
3068 - Standalone program support:
3069 CONFIG_STANDALONE_LOAD_ADDR
3071 This option defines a board specific value for the
3072 address where standalone program gets loaded, thus
3073 overwriting the architecture dependent default
3076 - Frame Buffer Address:
3079 Define CONFIG_FB_ADDR if you want to use specific
3080 address for frame buffer. This is typically the case
3081 when using a graphics controller has separate video
3082 memory. U-Boot will then place the frame buffer at
3083 the given address instead of dynamically reserving it
3084 in system RAM by calling lcd_setmem(), which grabs
3085 the memory for the frame buffer depending on the
3086 configured panel size.
3088 Please see board_init_f function.
3090 - Automatic software updates via TFTP server
3092 CONFIG_UPDATE_TFTP_CNT_MAX
3093 CONFIG_UPDATE_TFTP_MSEC_MAX
3095 These options enable and control the auto-update feature;
3096 for a more detailed description refer to doc/README.update.
3098 - MTD Support (mtdparts command, UBI support)
3101 Adds the MTD device infrastructure from the Linux kernel.
3102 Needed for mtdparts command support.
3104 CONFIG_MTD_PARTITIONS
3106 Adds the MTD partitioning infrastructure from the Linux
3107 kernel. Needed for UBI support.
3112 Adds commands for interacting with MTD partitions formatted
3113 with the UBI flash translation layer
3115 Requires also defining CONFIG_RBTREE
3117 CONFIG_UBI_SILENCE_MSG
3119 Make the verbose messages from UBI stop printing. This leaves
3120 warnings and errors enabled.
3123 CONFIG_MTD_UBI_WL_THRESHOLD
3124 This parameter defines the maximum difference between the highest
3125 erase counter value and the lowest erase counter value of eraseblocks
3126 of UBI devices. When this threshold is exceeded, UBI starts performing
3127 wear leveling by means of moving data from eraseblock with low erase
3128 counter to eraseblocks with high erase counter.
3130 The default value should be OK for SLC NAND flashes, NOR flashes and
3131 other flashes which have eraseblock life-cycle 100000 or more.
3132 However, in case of MLC NAND flashes which typically have eraseblock
3133 life-cycle less than 10000, the threshold should be lessened (e.g.,
3134 to 128 or 256, although it does not have to be power of 2).
3138 CONFIG_MTD_UBI_BEB_LIMIT
3139 This option specifies the maximum bad physical eraseblocks UBI
3140 expects on the MTD device (per 1024 eraseblocks). If the
3141 underlying flash does not admit of bad eraseblocks (e.g. NOR
3142 flash), this value is ignored.
3144 NAND datasheets often specify the minimum and maximum NVM
3145 (Number of Valid Blocks) for the flashes' endurance lifetime.
3146 The maximum expected bad eraseblocks per 1024 eraseblocks
3147 then can be calculated as "1024 * (1 - MinNVB / MaxNVB)",
3148 which gives 20 for most NANDs (MaxNVB is basically the total
3149 count of eraseblocks on the chip).
3151 To put it differently, if this value is 20, UBI will try to
3152 reserve about 1.9% of physical eraseblocks for bad blocks
3153 handling. And that will be 1.9% of eraseblocks on the entire
3154 NAND chip, not just the MTD partition UBI attaches. This means
3155 that if you have, say, a NAND flash chip admits maximum 40 bad
3156 eraseblocks, and it is split on two MTD partitions of the same
3157 size, UBI will reserve 40 eraseblocks when attaching a
3162 CONFIG_MTD_UBI_FASTMAP
3163 Fastmap is a mechanism which allows attaching an UBI device
3164 in nearly constant time. Instead of scanning the whole MTD device it
3165 only has to locate a checkpoint (called fastmap) on the device.
3166 The on-flash fastmap contains all information needed to attach
3167 the device. Using fastmap makes only sense on large devices where
3168 attaching by scanning takes long. UBI will not automatically install
3169 a fastmap on old images, but you can set the UBI parameter
3170 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT to 1 if you want so. Please note
3171 that fastmap-enabled images are still usable with UBI implementations
3172 without fastmap support. On typical flash devices the whole fastmap
3173 fits into one PEB. UBI will reserve PEBs to hold two fastmaps.
3175 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT
3176 Set this parameter to enable fastmap automatically on images
3180 CONFIG_MTD_UBI_FM_DEBUG
3181 Enable UBI fastmap debug
3187 Adds commands for interacting with UBI volumes formatted as
3188 UBIFS. UBIFS is read-only in u-boot.
3190 Requires UBI support as well as CONFIG_LZO
3192 CONFIG_UBIFS_SILENCE_MSG
3194 Make the verbose messages from UBIFS stop printing. This leaves
3195 warnings and errors enabled.
3199 Enable building of SPL globally.
3202 LDSCRIPT for linking the SPL binary.
3204 CONFIG_SPL_MAX_FOOTPRINT
3205 Maximum size in memory allocated to the SPL, BSS included.
3206 When defined, the linker checks that the actual memory
3207 used by SPL from _start to __bss_end does not exceed it.
3208 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3209 must not be both defined at the same time.
3212 Maximum size of the SPL image (text, data, rodata, and
3213 linker lists sections), BSS excluded.
3214 When defined, the linker checks that the actual size does
3217 CONFIG_SPL_TEXT_BASE
3218 TEXT_BASE for linking the SPL binary.
3220 CONFIG_SPL_RELOC_TEXT_BASE
3221 Address to relocate to. If unspecified, this is equal to
3222 CONFIG_SPL_TEXT_BASE (i.e. no relocation is done).
3224 CONFIG_SPL_BSS_START_ADDR
3225 Link address for the BSS within the SPL binary.
3227 CONFIG_SPL_BSS_MAX_SIZE
3228 Maximum size in memory allocated to the SPL BSS.
3229 When defined, the linker checks that the actual memory used
3230 by SPL from __bss_start to __bss_end does not exceed it.
3231 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3232 must not be both defined at the same time.
3235 Adress of the start of the stack SPL will use
3237 CONFIG_SPL_PANIC_ON_RAW_IMAGE
3238 When defined, SPL will panic() if the image it has
3239 loaded does not have a signature.
3240 Defining this is useful when code which loads images
3241 in SPL cannot guarantee that absolutely all read errors
3243 An example is the LPC32XX MLC NAND driver, which will
3244 consider that a completely unreadable NAND block is bad,
3245 and thus should be skipped silently.
3247 CONFIG_SPL_RELOC_STACK
3248 Adress of the start of the stack SPL will use after
3249 relocation. If unspecified, this is equal to
3252 CONFIG_SYS_SPL_MALLOC_START
3253 Starting address of the malloc pool used in SPL.
3254 When this option is set the full malloc is used in SPL and
3255 it is set up by spl_init() and before that, the simple malloc()
3256 can be used if CONFIG_SYS_MALLOC_F is defined.
3258 CONFIG_SYS_SPL_MALLOC_SIZE
3259 The size of the malloc pool used in SPL.
3261 CONFIG_SPL_FRAMEWORK
3262 Enable the SPL framework under common/. This framework
3263 supports MMC, NAND and YMODEM loading of U-Boot and NAND
3264 NAND loading of the Linux Kernel.
3267 Enable booting directly to an OS from SPL.
3268 See also: doc/README.falcon
3270 CONFIG_SPL_DISPLAY_PRINT
3271 For ARM, enable an optional function to print more information
3272 about the running system.
3274 CONFIG_SPL_INIT_MINIMAL
3275 Arch init code should be built for a very small image
3277 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_PARTITION
3278 Partition on the MMC to load U-Boot from when the MMC is being
3281 CONFIG_SYS_MMCSD_RAW_MODE_KERNEL_SECTOR
3282 Sector to load kernel uImage from when MMC is being
3283 used in raw mode (for Falcon mode)
3285 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTOR,
3286 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTORS
3287 Sector and number of sectors to load kernel argument
3288 parameters from when MMC is being used in raw mode
3291 CONFIG_SYS_MMCSD_FS_BOOT_PARTITION
3292 Partition on the MMC to load U-Boot from when the MMC is being
3295 CONFIG_SPL_FS_LOAD_PAYLOAD_NAME
3296 Filename to read to load U-Boot when reading from filesystem
3298 CONFIG_SPL_FS_LOAD_KERNEL_NAME
3299 Filename to read to load kernel uImage when reading
3300 from filesystem (for Falcon mode)
3302 CONFIG_SPL_FS_LOAD_ARGS_NAME
3303 Filename to read to load kernel argument parameters
3304 when reading from filesystem (for Falcon mode)
3306 CONFIG_SPL_MPC83XX_WAIT_FOR_NAND
3307 Set this for NAND SPL on PPC mpc83xx targets, so that
3308 start.S waits for the rest of the SPL to load before
3309 continuing (the hardware starts execution after just
3310 loading the first page rather than the full 4K).
3312 CONFIG_SPL_SKIP_RELOCATE
3313 Avoid SPL relocation
3315 CONFIG_SPL_NAND_BASE
3316 Include nand_base.c in the SPL. Requires
3317 CONFIG_SPL_NAND_DRIVERS.
3319 CONFIG_SPL_NAND_DRIVERS
3320 SPL uses normal NAND drivers, not minimal drivers.
3323 Include standard software ECC in the SPL
3325 CONFIG_SPL_NAND_SIMPLE
3326 Support for NAND boot using simple NAND drivers that
3327 expose the cmd_ctrl() interface.
3330 Support for a lightweight UBI (fastmap) scanner and
3333 CONFIG_SPL_NAND_RAW_ONLY
3334 Support to boot only raw u-boot.bin images. Use this only
3335 if you need to save space.
3337 CONFIG_SPL_COMMON_INIT_DDR
3338 Set for common ddr init with serial presence detect in
3341 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
3342 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
3343 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
3344 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
3345 CONFIG_SYS_NAND_ECCBYTES
3346 Defines the size and behavior of the NAND that SPL uses
3349 CONFIG_SPL_NAND_BOOT
3350 Add support NAND boot
3352 CONFIG_SYS_NAND_U_BOOT_OFFS
3353 Location in NAND to read U-Boot from
3355 CONFIG_SYS_NAND_U_BOOT_DST
3356 Location in memory to load U-Boot to
3358 CONFIG_SYS_NAND_U_BOOT_SIZE
3359 Size of image to load
3361 CONFIG_SYS_NAND_U_BOOT_START
3362 Entry point in loaded image to jump to
3364 CONFIG_SYS_NAND_HW_ECC_OOBFIRST
3365 Define this if you need to first read the OOB and then the
3366 data. This is used, for example, on davinci platforms.
3368 CONFIG_SPL_OMAP3_ID_NAND
3369 Support for an OMAP3-specific set of functions to return the
3370 ID and MFR of the first attached NAND chip, if present.
3372 CONFIG_SPL_RAM_DEVICE
3373 Support for running image already present in ram, in SPL binary
3376 Image offset to which the SPL should be padded before appending
3377 the SPL payload. By default, this is defined as
3378 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3379 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3380 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3383 Final target image containing SPL and payload. Some SPLs
3384 use an arch-specific makefile fragment instead, for
3385 example if more than one image needs to be produced.
3387 CONFIG_FIT_SPL_PRINT
3388 Printing information about a FIT image adds quite a bit of
3389 code to SPL. So this is normally disabled in SPL. Use this
3390 option to re-enable it. This will affect the output of the
3391 bootm command when booting a FIT image.
3395 Enable building of TPL globally.
3398 Image offset to which the TPL should be padded before appending
3399 the TPL payload. By default, this is defined as
3400 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3401 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3402 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3404 - Interrupt support (PPC):
3406 There are common interrupt_init() and timer_interrupt()
3407 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
3408 for CPU specific initialization. interrupt_init_cpu()
3409 should set decrementer_count to appropriate value. If
3410 CPU resets decrementer automatically after interrupt
3411 (ppc4xx) it should set decrementer_count to zero.
3412 timer_interrupt() calls timer_interrupt_cpu() for CPU
3413 specific handling. If board has watchdog / status_led
3414 / other_activity_monitor it works automatically from
3415 general timer_interrupt().
3418 Board initialization settings:
3419 ------------------------------
3421 During Initialization u-boot calls a number of board specific functions
3422 to allow the preparation of board specific prerequisites, e.g. pin setup
3423 before drivers are initialized. To enable these callbacks the
3424 following configuration macros have to be defined. Currently this is
3425 architecture specific, so please check arch/your_architecture/lib/board.c
3426 typically in board_init_f() and board_init_r().
3428 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
3429 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
3430 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
3431 - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
3433 Configuration Settings:
3434 -----------------------
3436 - CONFIG_SYS_SUPPORT_64BIT_DATA: Defined automatically if compiled as 64-bit.
3437 Optionally it can be defined to support 64-bit memory commands.
3439 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
3440 undefine this when you're short of memory.
3442 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
3443 width of the commands listed in the 'help' command output.
3445 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
3446 prompt for user input.
3448 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
3450 - CONFIG_SYS_PBSIZE: Buffer size for Console output
3452 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
3454 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
3455 the application (usually a Linux kernel) when it is
3458 - CONFIG_SYS_BAUDRATE_TABLE:
3459 List of legal baudrate settings for this board.
3461 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
3462 Begin and End addresses of the area used by the
3465 - CONFIG_SYS_ALT_MEMTEST:
3466 Enable an alternate, more extensive memory test.
3468 - CONFIG_SYS_MEMTEST_SCRATCH:
3469 Scratch address used by the alternate memory test
3470 You only need to set this if address zero isn't writeable
3472 - CONFIG_SYS_MEM_RESERVE_SECURE
3473 Only implemented for ARMv8 for now.
3474 If defined, the size of CONFIG_SYS_MEM_RESERVE_SECURE memory
3475 is substracted from total RAM and won't be reported to OS.
3476 This memory can be used as secure memory. A variable
3477 gd->arch.secure_ram is used to track the location. In systems
3478 the RAM base is not zero, or RAM is divided into banks,
3479 this variable needs to be recalcuated to get the address.
3481 - CONFIG_SYS_MEM_TOP_HIDE:
3482 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
3483 this specified memory area will get subtracted from the top
3484 (end) of RAM and won't get "touched" at all by U-Boot. By
3485 fixing up gd->ram_size the Linux kernel should gets passed
3486 the now "corrected" memory size and won't touch it either.
3487 This should work for arch/ppc and arch/powerpc. Only Linux
3488 board ports in arch/powerpc with bootwrapper support that
3489 recalculate the memory size from the SDRAM controller setup
3490 will have to get fixed in Linux additionally.
3492 This option can be used as a workaround for the 440EPx/GRx
3493 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
3496 WARNING: Please make sure that this value is a multiple of
3497 the Linux page size (normally 4k). If this is not the case,
3498 then the end address of the Linux memory will be located at a
3499 non page size aligned address and this could cause major
3502 - CONFIG_SYS_LOADS_BAUD_CHANGE:
3503 Enable temporary baudrate change while serial download
3505 - CONFIG_SYS_SDRAM_BASE:
3506 Physical start address of SDRAM. _Must_ be 0 here.
3508 - CONFIG_SYS_FLASH_BASE:
3509 Physical start address of Flash memory.
3511 - CONFIG_SYS_MONITOR_BASE:
3512 Physical start address of boot monitor code (set by
3513 make config files to be same as the text base address
3514 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
3515 CONFIG_SYS_FLASH_BASE when booting from flash.
3517 - CONFIG_SYS_MONITOR_LEN:
3518 Size of memory reserved for monitor code, used to
3519 determine _at_compile_time_ (!) if the environment is
3520 embedded within the U-Boot image, or in a separate
3523 - CONFIG_SYS_MALLOC_LEN:
3524 Size of DRAM reserved for malloc() use.
3526 - CONFIG_SYS_MALLOC_F_LEN
3527 Size of the malloc() pool for use before relocation. If
3528 this is defined, then a very simple malloc() implementation
3529 will become available before relocation. The address is just
3530 below the global data, and the stack is moved down to make
3533 This feature allocates regions with increasing addresses
3534 within the region. calloc() is supported, but realloc()
3535 is not available. free() is supported but does nothing.
3536 The memory will be freed (or in fact just forgotten) when
3537 U-Boot relocates itself.
3539 - CONFIG_SYS_MALLOC_SIMPLE
3540 Provides a simple and small malloc() and calloc() for those
3541 boards which do not use the full malloc in SPL (which is
3542 enabled with CONFIG_SYS_SPL_MALLOC_START).
3544 - CONFIG_SYS_NONCACHED_MEMORY:
3545 Size of non-cached memory area. This area of memory will be
3546 typically located right below the malloc() area and mapped
3547 uncached in the MMU. This is useful for drivers that would
3548 otherwise require a lot of explicit cache maintenance. For
3549 some drivers it's also impossible to properly maintain the
3550 cache. For example if the regions that need to be flushed
3551 are not a multiple of the cache-line size, *and* padding
3552 cannot be allocated between the regions to align them (i.e.
3553 if the HW requires a contiguous array of regions, and the
3554 size of each region is not cache-aligned), then a flush of
3555 one region may result in overwriting data that hardware has
3556 written to another region in the same cache-line. This can
3557 happen for example in network drivers where descriptors for
3558 buffers are typically smaller than the CPU cache-line (e.g.
3559 16 bytes vs. 32 or 64 bytes).
3561 Non-cached memory is only supported on 32-bit ARM at present.
3563 - CONFIG_SYS_BOOTM_LEN:
3564 Normally compressed uImages are limited to an
3565 uncompressed size of 8 MBytes. If this is not enough,
3566 you can define CONFIG_SYS_BOOTM_LEN in your board config file
3567 to adjust this setting to your needs.
3569 - CONFIG_SYS_BOOTMAPSZ:
3570 Maximum size of memory mapped by the startup code of
3571 the Linux kernel; all data that must be processed by
3572 the Linux kernel (bd_info, boot arguments, FDT blob if
3573 used) must be put below this limit, unless "bootm_low"
3574 environment variable is defined and non-zero. In such case
3575 all data for the Linux kernel must be between "bootm_low"
3576 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
3577 variable "bootm_mapsize" will override the value of
3578 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
3579 then the value in "bootm_size" will be used instead.
3581 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
3582 Enable initrd_high functionality. If defined then the
3583 initrd_high feature is enabled and the bootm ramdisk subcommand
3586 - CONFIG_SYS_BOOT_GET_CMDLINE:
3587 Enables allocating and saving kernel cmdline in space between
3588 "bootm_low" and "bootm_low" + BOOTMAPSZ.
3590 - CONFIG_SYS_BOOT_GET_KBD:
3591 Enables allocating and saving a kernel copy of the bd_info in
3592 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
3594 - CONFIG_SYS_MAX_FLASH_BANKS:
3595 Max number of Flash memory banks
3597 - CONFIG_SYS_MAX_FLASH_SECT:
3598 Max number of sectors on a Flash chip
3600 - CONFIG_SYS_FLASH_ERASE_TOUT:
3601 Timeout for Flash erase operations (in ms)
3603 - CONFIG_SYS_FLASH_WRITE_TOUT:
3604 Timeout for Flash write operations (in ms)
3606 - CONFIG_SYS_FLASH_LOCK_TOUT
3607 Timeout for Flash set sector lock bit operation (in ms)
3609 - CONFIG_SYS_FLASH_UNLOCK_TOUT
3610 Timeout for Flash clear lock bits operation (in ms)
3612 - CONFIG_SYS_FLASH_PROTECTION
3613 If defined, hardware flash sectors protection is used
3614 instead of U-Boot software protection.
3616 - CONFIG_SYS_DIRECT_FLASH_TFTP:
3618 Enable TFTP transfers directly to flash memory;
3619 without this option such a download has to be
3620 performed in two steps: (1) download to RAM, and (2)
3621 copy from RAM to flash.
3623 The two-step approach is usually more reliable, since
3624 you can check if the download worked before you erase
3625 the flash, but in some situations (when system RAM is
3626 too limited to allow for a temporary copy of the
3627 downloaded image) this option may be very useful.
3629 - CONFIG_SYS_FLASH_CFI:
3630 Define if the flash driver uses extra elements in the
3631 common flash structure for storing flash geometry.
3633 - CONFIG_FLASH_CFI_DRIVER
3634 This option also enables the building of the cfi_flash driver
3635 in the drivers directory
3637 - CONFIG_FLASH_CFI_MTD
3638 This option enables the building of the cfi_mtd driver
3639 in the drivers directory. The driver exports CFI flash
3642 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
3643 Use buffered writes to flash.
3645 - CONFIG_FLASH_SPANSION_S29WS_N
3646 s29ws-n MirrorBit flash has non-standard addresses for buffered
3649 - CONFIG_SYS_FLASH_QUIET_TEST
3650 If this option is defined, the common CFI flash doesn't
3651 print it's warning upon not recognized FLASH banks. This
3652 is useful, if some of the configured banks are only
3653 optionally available.
3655 - CONFIG_FLASH_SHOW_PROGRESS
3656 If defined (must be an integer), print out countdown
3657 digits and dots. Recommended value: 45 (9..1) for 80
3658 column displays, 15 (3..1) for 40 column displays.
3660 - CONFIG_FLASH_VERIFY
3661 If defined, the content of the flash (destination) is compared
3662 against the source after the write operation. An error message
3663 will be printed when the contents are not identical.
3664 Please note that this option is useless in nearly all cases,
3665 since such flash programming errors usually are detected earlier
3666 while unprotecting/erasing/programming. Please only enable
3667 this option if you really know what you are doing.
3669 - CONFIG_SYS_RX_ETH_BUFFER:
3670 Defines the number of Ethernet receive buffers. On some
3671 Ethernet controllers it is recommended to set this value
3672 to 8 or even higher (EEPRO100 or 405 EMAC), since all
3673 buffers can be full shortly after enabling the interface
3674 on high Ethernet traffic.
3675 Defaults to 4 if not defined.
3677 - CONFIG_ENV_MAX_ENTRIES
3679 Maximum number of entries in the hash table that is used
3680 internally to store the environment settings. The default
3681 setting is supposed to be generous and should work in most
3682 cases. This setting can be used to tune behaviour; see
3683 lib/hashtable.c for details.
3685 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3686 - CONFIG_ENV_FLAGS_LIST_STATIC
3687 Enable validation of the values given to environment variables when
3688 calling env set. Variables can be restricted to only decimal,
3689 hexadecimal, or boolean. If CONFIG_CMD_NET is also defined,
3690 the variables can also be restricted to IP address or MAC address.
3692 The format of the list is:
3693 type_attribute = [s|d|x|b|i|m]
3694 access_attribute = [a|r|o|c]
3695 attributes = type_attribute[access_attribute]
3696 entry = variable_name[:attributes]
3699 The type attributes are:
3700 s - String (default)
3703 b - Boolean ([1yYtT|0nNfF])
3707 The access attributes are:
3713 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3714 Define this to a list (string) to define the ".flags"
3715 environment variable in the default or embedded environment.
3717 - CONFIG_ENV_FLAGS_LIST_STATIC
3718 Define this to a list (string) to define validation that
3719 should be done if an entry is not found in the ".flags"
3720 environment variable. To override a setting in the static
3721 list, simply add an entry for the same variable name to the
3724 If CONFIG_REGEX is defined, the variable_name above is evaluated as a
3725 regular expression. This allows multiple variables to define the same
3726 flags without explicitly listing them for each variable.
3728 - CONFIG_ENV_ACCESS_IGNORE_FORCE
3729 If defined, don't allow the -f switch to env set override variable
3732 - CONFIG_OMAP_PLATFORM_RESET_TIME_MAX_USEC (OMAP only)
3733 This is set by OMAP boards for the max time that reset should
3734 be asserted. See doc/README.omap-reset-time for details on how
3735 the value can be calculated on a given board.
3738 If stdint.h is available with your toolchain you can define this
3739 option to enable it. You can provide option 'USE_STDINT=1' when
3740 building U-Boot to enable this.
3742 The following definitions that deal with the placement and management
3743 of environment data (variable area); in general, we support the
3744 following configurations:
3746 - CONFIG_BUILD_ENVCRC:
3748 Builds up envcrc with the target environment so that external utils
3749 may easily extract it and embed it in final U-Boot images.
3751 - CONFIG_ENV_IS_IN_FLASH:
3753 Define this if the environment is in flash memory.
3755 a) The environment occupies one whole flash sector, which is
3756 "embedded" in the text segment with the U-Boot code. This
3757 happens usually with "bottom boot sector" or "top boot
3758 sector" type flash chips, which have several smaller
3759 sectors at the start or the end. For instance, such a
3760 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
3761 such a case you would place the environment in one of the
3762 4 kB sectors - with U-Boot code before and after it. With
3763 "top boot sector" type flash chips, you would put the
3764 environment in one of the last sectors, leaving a gap
3765 between U-Boot and the environment.
3767 - CONFIG_ENV_OFFSET:
3769 Offset of environment data (variable area) to the
3770 beginning of flash memory; for instance, with bottom boot
3771 type flash chips the second sector can be used: the offset
3772 for this sector is given here.
3774 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
3778 This is just another way to specify the start address of
3779 the flash sector containing the environment (instead of
3782 - CONFIG_ENV_SECT_SIZE:
3784 Size of the sector containing the environment.
3787 b) Sometimes flash chips have few, equal sized, BIG sectors.
3788 In such a case you don't want to spend a whole sector for
3793 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
3794 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
3795 of this flash sector for the environment. This saves
3796 memory for the RAM copy of the environment.
3798 It may also save flash memory if you decide to use this
3799 when your environment is "embedded" within U-Boot code,
3800 since then the remainder of the flash sector could be used
3801 for U-Boot code. It should be pointed out that this is
3802 STRONGLY DISCOURAGED from a robustness point of view:
3803 updating the environment in flash makes it always
3804 necessary to erase the WHOLE sector. If something goes
3805 wrong before the contents has been restored from a copy in
3806 RAM, your target system will be dead.
3808 - CONFIG_ENV_ADDR_REDUND
3809 CONFIG_ENV_SIZE_REDUND
3811 These settings describe a second storage area used to hold
3812 a redundant copy of the environment data, so that there is
3813 a valid backup copy in case there is a power failure during
3814 a "saveenv" operation.
3816 BE CAREFUL! Any changes to the flash layout, and some changes to the
3817 source code will make it necessary to adapt <board>/u-boot.lds*
3821 - CONFIG_ENV_IS_IN_NVRAM:
3823 Define this if you have some non-volatile memory device
3824 (NVRAM, battery buffered SRAM) which you want to use for the
3830 These two #defines are used to determine the memory area you
3831 want to use for environment. It is assumed that this memory
3832 can just be read and written to, without any special
3835 BE CAREFUL! The first access to the environment happens quite early
3836 in U-Boot initialization (when we try to get the setting of for the
3837 console baudrate). You *MUST* have mapped your NVRAM area then, or
3840 Please note that even with NVRAM we still use a copy of the
3841 environment in RAM: we could work on NVRAM directly, but we want to
3842 keep settings there always unmodified except somebody uses "saveenv"
3843 to save the current settings.
3846 - CONFIG_ENV_IS_IN_EEPROM:
3848 Use this if you have an EEPROM or similar serial access
3849 device and a driver for it.
3851 - CONFIG_ENV_OFFSET:
3854 These two #defines specify the offset and size of the
3855 environment area within the total memory of your EEPROM.
3857 - CONFIG_SYS_I2C_EEPROM_ADDR:
3858 If defined, specified the chip address of the EEPROM device.
3859 The default address is zero.
3861 - CONFIG_SYS_I2C_EEPROM_BUS:
3862 If defined, specified the i2c bus of the EEPROM device.
3864 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
3865 If defined, the number of bits used to address bytes in a
3866 single page in the EEPROM device. A 64 byte page, for example
3867 would require six bits.
3869 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
3870 If defined, the number of milliseconds to delay between
3871 page writes. The default is zero milliseconds.
3873 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
3874 The length in bytes of the EEPROM memory array address. Note
3875 that this is NOT the chip address length!
3877 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
3878 EEPROM chips that implement "address overflow" are ones
3879 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
3880 address and the extra bits end up in the "chip address" bit
3881 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
3884 Note that we consider the length of the address field to
3885 still be one byte because the extra address bits are hidden
3886 in the chip address.
3888 - CONFIG_SYS_EEPROM_SIZE:
3889 The size in bytes of the EEPROM device.
3891 - CONFIG_ENV_EEPROM_IS_ON_I2C
3892 define this, if you have I2C and SPI activated, and your
3893 EEPROM, which holds the environment, is on the I2C bus.
3895 - CONFIG_I2C_ENV_EEPROM_BUS
3896 if you have an Environment on an EEPROM reached over
3897 I2C muxes, you can define here, how to reach this
3898 EEPROM. For example:
3900 #define CONFIG_I2C_ENV_EEPROM_BUS 1
3902 EEPROM which holds the environment, is reached over
3903 a pca9547 i2c mux with address 0x70, channel 3.
3905 - CONFIG_ENV_IS_IN_DATAFLASH:
3907 Define this if you have a DataFlash memory device which you
3908 want to use for the environment.
3910 - CONFIG_ENV_OFFSET:
3914 These three #defines specify the offset and size of the
3915 environment area within the total memory of your DataFlash placed
3916 at the specified address.
3918 - CONFIG_ENV_IS_IN_SPI_FLASH:
3920 Define this if you have a SPI Flash memory device which you
3921 want to use for the environment.
3923 - CONFIG_ENV_OFFSET:
3926 These two #defines specify the offset and size of the
3927 environment area within the SPI Flash. CONFIG_ENV_OFFSET must be
3928 aligned to an erase sector boundary.
3930 - CONFIG_ENV_SECT_SIZE:
3932 Define the SPI flash's sector size.
3934 - CONFIG_ENV_OFFSET_REDUND (optional):
3936 This setting describes a second storage area of CONFIG_ENV_SIZE
3937 size used to hold a redundant copy of the environment data, so
3938 that there is a valid backup copy in case there is a power failure
3939 during a "saveenv" operation. CONFIG_ENV_OFFSET_REDUND must be
3940 aligned to an erase sector boundary.
3942 - CONFIG_ENV_SPI_BUS (optional):
3943 - CONFIG_ENV_SPI_CS (optional):
3945 Define the SPI bus and chip select. If not defined they will be 0.
3947 - CONFIG_ENV_SPI_MAX_HZ (optional):
3949 Define the SPI max work clock. If not defined then use 1MHz.
3951 - CONFIG_ENV_SPI_MODE (optional):
3953 Define the SPI work mode. If not defined then use SPI_MODE_3.
3955 - CONFIG_ENV_IS_IN_REMOTE:
3957 Define this if you have a remote memory space which you
3958 want to use for the local device's environment.
3963 These two #defines specify the address and size of the
3964 environment area within the remote memory space. The
3965 local device can get the environment from remote memory
3966 space by SRIO or PCIE links.
3968 BE CAREFUL! For some special cases, the local device can not use
3969 "saveenv" command. For example, the local device will get the
3970 environment stored in a remote NOR flash by SRIO or PCIE link,
3971 but it can not erase, write this NOR flash by SRIO or PCIE interface.
3973 - CONFIG_ENV_IS_IN_NAND:
3975 Define this if you have a NAND device which you want to use
3976 for the environment.
3978 - CONFIG_ENV_OFFSET:
3981 These two #defines specify the offset and size of the environment
3982 area within the first NAND device. CONFIG_ENV_OFFSET must be
3983 aligned to an erase block boundary.
3985 - CONFIG_ENV_OFFSET_REDUND (optional):
3987 This setting describes a second storage area of CONFIG_ENV_SIZE
3988 size used to hold a redundant copy of the environment data, so
3989 that there is a valid backup copy in case there is a power failure
3990 during a "saveenv" operation. CONFIG_ENV_OFFSET_REDUND must be
3991 aligned to an erase block boundary.
3993 - CONFIG_ENV_RANGE (optional):
3995 Specifies the length of the region in which the environment
3996 can be written. This should be a multiple of the NAND device's
3997 block size. Specifying a range with more erase blocks than
3998 are needed to hold CONFIG_ENV_SIZE allows bad blocks within
3999 the range to be avoided.
4001 - CONFIG_ENV_OFFSET_OOB (optional):
4003 Enables support for dynamically retrieving the offset of the
4004 environment from block zero's out-of-band data. The
4005 "nand env.oob" command can be used to record this offset.
4006 Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
4007 using CONFIG_ENV_OFFSET_OOB.
4009 - CONFIG_NAND_ENV_DST
4011 Defines address in RAM to which the nand_spl code should copy the
4012 environment. If redundant environment is used, it will be copied to
4013 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
4015 - CONFIG_ENV_IS_IN_UBI:
4017 Define this if you have an UBI volume that you want to use for the
4018 environment. This has the benefit of wear-leveling the environment
4019 accesses, which is important on NAND.
4021 - CONFIG_ENV_UBI_PART:
4023 Define this to a string that is the mtd partition containing the UBI.
4025 - CONFIG_ENV_UBI_VOLUME:
4027 Define this to the name of the volume that you want to store the
4030 - CONFIG_ENV_UBI_VOLUME_REDUND:
4032 Define this to the name of another volume to store a second copy of
4033 the environment in. This will enable redundant environments in UBI.
4034 It is assumed that both volumes are in the same MTD partition.
4036 - CONFIG_UBI_SILENCE_MSG
4037 - CONFIG_UBIFS_SILENCE_MSG
4039 You will probably want to define these to avoid a really noisy system
4040 when storing the env in UBI.
4042 - CONFIG_ENV_IS_IN_FAT:
4043 Define this if you want to use the FAT file system for the environment.
4045 - FAT_ENV_INTERFACE:
4047 Define this to a string that is the name of the block device.
4049 - FAT_ENV_DEVICE_AND_PART:
4051 Define this to a string to specify the partition of the device. It can
4054 "D:P", "D:0", "D", "D:" or "D:auto" (D, P are integers. And P >= 1)
4055 - "D:P": device D partition P. Error occurs if device D has no
4058 - "D" or "D:": device D partition 1 if device D has partition
4059 table, or the whole device D if has no partition
4061 - "D:auto": first partition in device D with bootable flag set.
4062 If none, first valid partition in device D. If no
4063 partition table then means device D.
4067 It's a string of the FAT file name. This file use to store the
4071 This should be defined. Otherwise it cannot save the environment file.
4073 - CONFIG_ENV_IS_IN_MMC:
4075 Define this if you have an MMC device which you want to use for the
4078 - CONFIG_SYS_MMC_ENV_DEV:
4080 Specifies which MMC device the environment is stored in.
4082 - CONFIG_SYS_MMC_ENV_PART (optional):
4084 Specifies which MMC partition the environment is stored in. If not
4085 set, defaults to partition 0, the user area. Common values might be
4086 1 (first MMC boot partition), 2 (second MMC boot partition).
4088 - CONFIG_ENV_OFFSET:
4091 These two #defines specify the offset and size of the environment
4092 area within the specified MMC device.
4094 If offset is positive (the usual case), it is treated as relative to
4095 the start of the MMC partition. If offset is negative, it is treated
4096 as relative to the end of the MMC partition. This can be useful if
4097 your board may be fitted with different MMC devices, which have
4098 different sizes for the MMC partitions, and you always want the
4099 environment placed at the very end of the partition, to leave the
4100 maximum possible space before it, to store other data.
4102 These two values are in units of bytes, but must be aligned to an
4103 MMC sector boundary.
4105 - CONFIG_ENV_OFFSET_REDUND (optional):
4107 Specifies a second storage area, of CONFIG_ENV_SIZE size, used to
4108 hold a redundant copy of the environment data. This provides a
4109 valid backup copy in case the other copy is corrupted, e.g. due
4110 to a power failure during a "saveenv" operation.
4112 This value may also be positive or negative; this is handled in the
4113 same way as CONFIG_ENV_OFFSET.
4115 This value is also in units of bytes, but must also be aligned to
4116 an MMC sector boundary.
4118 - CONFIG_ENV_SIZE_REDUND (optional):
4120 This value need not be set, even when CONFIG_ENV_OFFSET_REDUND is
4121 set. If this value is set, it must be set to the same value as
4124 - CONFIG_SYS_SPI_INIT_OFFSET
4126 Defines offset to the initial SPI buffer area in DPRAM. The
4127 area is used at an early stage (ROM part) if the environment
4128 is configured to reside in the SPI EEPROM: We need a 520 byte
4129 scratch DPRAM area. It is used between the two initialization
4130 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
4131 to be a good choice since it makes it far enough from the
4132 start of the data area as well as from the stack pointer.
4134 Please note that the environment is read-only until the monitor
4135 has been relocated to RAM and a RAM copy of the environment has been
4136 created; also, when using EEPROM you will have to use getenv_f()
4137 until then to read environment variables.
4139 The environment is protected by a CRC32 checksum. Before the monitor
4140 is relocated into RAM, as a result of a bad CRC you will be working
4141 with the compiled-in default environment - *silently*!!! [This is
4142 necessary, because the first environment variable we need is the
4143 "baudrate" setting for the console - if we have a bad CRC, we don't
4144 have any device yet where we could complain.]
4146 Note: once the monitor has been relocated, then it will complain if
4147 the default environment is used; a new CRC is computed as soon as you
4148 use the "saveenv" command to store a valid environment.
4150 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
4151 Echo the inverted Ethernet link state to the fault LED.
4153 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
4154 also needs to be defined.
4156 - CONFIG_SYS_FAULT_MII_ADDR:
4157 MII address of the PHY to check for the Ethernet link state.
4159 - CONFIG_NS16550_MIN_FUNCTIONS:
4160 Define this if you desire to only have use of the NS16550_init
4161 and NS16550_putc functions for the serial driver located at
4162 drivers/serial/ns16550.c. This option is useful for saving
4163 space for already greatly restricted images, including but not
4164 limited to NAND_SPL configurations.
4166 - CONFIG_DISPLAY_BOARDINFO
4167 Display information about the board that U-Boot is running on
4168 when U-Boot starts up. The board function checkboard() is called
4171 - CONFIG_DISPLAY_BOARDINFO_LATE
4172 Similar to the previous option, but display this information
4173 later, once stdio is running and output goes to the LCD, if
4176 - CONFIG_BOARD_SIZE_LIMIT:
4177 Maximum size of the U-Boot image. When defined, the
4178 build system checks that the actual size does not
4181 Low Level (hardware related) configuration options:
4182 ---------------------------------------------------
4184 - CONFIG_SYS_CACHELINE_SIZE:
4185 Cache Line Size of the CPU.
4187 - CONFIG_SYS_DEFAULT_IMMR:
4188 Default address of the IMMR after system reset.
4190 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
4191 and RPXsuper) to be able to adjust the position of
4192 the IMMR register after a reset.
4194 - CONFIG_SYS_CCSRBAR_DEFAULT:
4195 Default (power-on reset) physical address of CCSR on Freescale
4198 - CONFIG_SYS_CCSRBAR:
4199 Virtual address of CCSR. On a 32-bit build, this is typically
4200 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
4202 CONFIG_SYS_DEFAULT_IMMR must also be set to this value,
4203 for cross-platform code that uses that macro instead.
4205 - CONFIG_SYS_CCSRBAR_PHYS:
4206 Physical address of CCSR. CCSR can be relocated to a new
4207 physical address, if desired. In this case, this macro should
4208 be set to that address. Otherwise, it should be set to the
4209 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
4210 is typically relocated on 36-bit builds. It is recommended
4211 that this macro be defined via the _HIGH and _LOW macros:
4213 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
4214 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
4216 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
4217 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
4218 either 0 (32-bit build) or 0xF (36-bit build). This macro is
4219 used in assembly code, so it must not contain typecasts or
4220 integer size suffixes (e.g. "ULL").
4222 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
4223 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
4224 used in assembly code, so it must not contain typecasts or
4225 integer size suffixes (e.g. "ULL").
4227 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
4228 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
4229 forced to a value that ensures that CCSR is not relocated.
4231 - Floppy Disk Support:
4232 CONFIG_SYS_FDC_DRIVE_NUMBER
4234 the default drive number (default value 0)
4236 CONFIG_SYS_ISA_IO_STRIDE
4238 defines the spacing between FDC chipset registers
4241 CONFIG_SYS_ISA_IO_OFFSET
4243 defines the offset of register from address. It
4244 depends on which part of the data bus is connected to
4245 the FDC chipset. (default value 0)
4247 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
4248 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
4251 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
4252 fdc_hw_init() is called at the beginning of the FDC
4253 setup. fdc_hw_init() must be provided by the board
4254 source code. It is used to make hardware-dependent
4258 Most IDE controllers were designed to be connected with PCI
4259 interface. Only few of them were designed for AHB interface.
4260 When software is doing ATA command and data transfer to
4261 IDE devices through IDE-AHB controller, some additional
4262 registers accessing to these kind of IDE-AHB controller
4265 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
4266 DO NOT CHANGE unless you know exactly what you're
4267 doing! (11-4) [MPC8xx/82xx systems only]
4269 - CONFIG_SYS_INIT_RAM_ADDR:
4271 Start address of memory area that can be used for
4272 initial data and stack; please note that this must be
4273 writable memory that is working WITHOUT special
4274 initialization, i. e. you CANNOT use normal RAM which
4275 will become available only after programming the
4276 memory controller and running certain initialization
4279 U-Boot uses the following memory types:
4280 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
4281 - MPC824X: data cache
4282 - PPC4xx: data cache
4284 - CONFIG_SYS_GBL_DATA_OFFSET:
4286 Offset of the initial data structure in the memory
4287 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
4288 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
4289 data is located at the end of the available space
4290 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
4291 GENERATED_GBL_DATA_SIZE), and the initial stack is just
4292 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
4293 CONFIG_SYS_GBL_DATA_OFFSET) downward.
4296 On the MPC824X (or other systems that use the data
4297 cache for initial memory) the address chosen for
4298 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
4299 point to an otherwise UNUSED address space between
4300 the top of RAM and the start of the PCI space.
4302 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
4304 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
4306 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
4308 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
4310 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
4312 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
4314 - CONFIG_SYS_OR_TIMING_SDRAM:
4317 - CONFIG_SYS_MAMR_PTA:
4318 periodic timer for refresh
4320 - CONFIG_SYS_DER: Debug Event Register (37-47)
4322 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
4323 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
4324 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
4325 CONFIG_SYS_BR1_PRELIM:
4326 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
4328 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
4329 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
4330 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
4331 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
4333 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
4334 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
4335 Machine Mode Register and Memory Periodic Timer
4336 Prescaler definitions (SDRAM timing)
4338 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
4339 enable I2C microcode relocation patch (MPC8xx);
4340 define relocation offset in DPRAM [DSP2]
4342 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
4343 enable SMC microcode relocation patch (MPC8xx);
4344 define relocation offset in DPRAM [SMC1]
4346 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
4347 enable SPI microcode relocation patch (MPC8xx);
4348 define relocation offset in DPRAM [SCC4]
4350 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
4351 Offset of the bootmode word in DPRAM used by post
4352 (Power On Self Tests). This definition overrides
4353 #define'd default value in commproc.h resp.
4356 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
4357 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
4358 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
4359 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
4360 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
4361 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
4362 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
4363 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
4364 Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
4366 - CONFIG_PCI_DISABLE_PCIE:
4367 Disable PCI-Express on systems where it is supported but not
4370 - CONFIG_PCI_ENUM_ONLY
4371 Only scan through and get the devices on the buses.
4372 Don't do any setup work, presumably because someone or
4373 something has already done it, and we don't need to do it
4374 a second time. Useful for platforms that are pre-booted
4375 by coreboot or similar.
4377 - CONFIG_PCI_INDIRECT_BRIDGE:
4378 Enable support for indirect PCI bridges.
4381 Chip has SRIO or not
4384 Board has SRIO 1 port available
4387 Board has SRIO 2 port available
4389 - CONFIG_SRIO_PCIE_BOOT_MASTER
4390 Board can support master function for Boot from SRIO and PCIE
4392 - CONFIG_SYS_SRIOn_MEM_VIRT:
4393 Virtual Address of SRIO port 'n' memory region
4395 - CONFIG_SYS_SRIOn_MEM_PHYS:
4396 Physical Address of SRIO port 'n' memory region
4398 - CONFIG_SYS_SRIOn_MEM_SIZE:
4399 Size of SRIO port 'n' memory region
4401 - CONFIG_SYS_NAND_BUSWIDTH_16BIT
4402 Defined to tell the NAND controller that the NAND chip is using
4404 Not all NAND drivers use this symbol.
4405 Example of drivers that use it:
4406 - drivers/mtd/nand/ndfc.c
4407 - drivers/mtd/nand/mxc_nand.c
4409 - CONFIG_SYS_NDFC_EBC0_CFG
4410 Sets the EBC0_CFG register for the NDFC. If not defined
4411 a default value will be used.
4414 Get DDR timing information from an I2C EEPROM. Common
4415 with pluggable memory modules such as SODIMMs
4418 I2C address of the SPD EEPROM
4420 - CONFIG_SYS_SPD_BUS_NUM
4421 If SPD EEPROM is on an I2C bus other than the first
4422 one, specify here. Note that the value must resolve
4423 to something your driver can deal with.
4425 - CONFIG_SYS_DDR_RAW_TIMING
4426 Get DDR timing information from other than SPD. Common with
4427 soldered DDR chips onboard without SPD. DDR raw timing
4428 parameters are extracted from datasheet and hard-coded into
4429 header files or board specific files.
4431 - CONFIG_FSL_DDR_INTERACTIVE
4432 Enable interactive DDR debugging. See doc/README.fsl-ddr.
4434 - CONFIG_FSL_DDR_SYNC_REFRESH
4435 Enable sync of refresh for multiple controllers.
4437 - CONFIG_FSL_DDR_BIST
4438 Enable built-in memory test for Freescale DDR controllers.
4440 - CONFIG_SYS_83XX_DDR_USES_CS0
4441 Only for 83xx systems. If specified, then DDR should
4442 be configured using CS0 and CS1 instead of CS2 and CS3.
4444 - CONFIG_ETHER_ON_FEC[12]
4445 Define to enable FEC[12] on a 8xx series processor.
4447 - CONFIG_FEC[12]_PHY
4448 Define to the hardcoded PHY address which corresponds
4449 to the given FEC; i. e.
4450 #define CONFIG_FEC1_PHY 4
4451 means that the PHY with address 4 is connected to FEC1
4453 When set to -1, means to probe for first available.
4455 - CONFIG_FEC[12]_PHY_NORXERR
4456 The PHY does not have a RXERR line (RMII only).
4457 (so program the FEC to ignore it).
4460 Enable RMII mode for all FECs.
4461 Note that this is a global option, we can't
4462 have one FEC in standard MII mode and another in RMII mode.
4464 - CONFIG_CRC32_VERIFY
4465 Add a verify option to the crc32 command.
4468 => crc32 -v <address> <count> <crc32>
4470 Where address/count indicate a memory area
4471 and crc32 is the correct crc32 which the
4475 Add the "loopw" memory command. This only takes effect if
4476 the memory commands are activated globally (CONFIG_CMD_MEM).
4479 Add the "mdc" and "mwc" memory commands. These are cyclic
4484 This command will print 4 bytes (10,11,12,13) each 500 ms.
4486 => mwc.l 100 12345678 10
4487 This command will write 12345678 to address 100 all 10 ms.
4489 This only takes effect if the memory commands are activated
4490 globally (CONFIG_CMD_MEM).
4492 - CONFIG_SKIP_LOWLEVEL_INIT
4493 [ARM, NDS32, MIPS only] If this variable is defined, then certain
4494 low level initializations (like setting up the memory
4495 controller) are omitted and/or U-Boot does not
4496 relocate itself into RAM.
4498 Normally this variable MUST NOT be defined. The only
4499 exception is when U-Boot is loaded (to RAM) by some
4500 other boot loader or by a debugger which performs
4501 these initializations itself.
4503 - CONFIG_SKIP_LOWLEVEL_INIT_ONLY
4504 [ARM926EJ-S only] This allows just the call to lowlevel_init()
4505 to be skipped. The normal CP15 init (such as enabling the
4506 instruction cache) is still performed.
4509 Modifies the behaviour of start.S when compiling a loader
4510 that is executed before the actual U-Boot. E.g. when
4511 compiling a NAND SPL.
4514 Modifies the behaviour of start.S when compiling a loader
4515 that is executed after the SPL and before the actual U-Boot.
4516 It is loaded by the SPL.
4518 - CONFIG_SYS_MPC85XX_NO_RESETVEC
4519 Only for 85xx systems. If this variable is specified, the section
4520 .resetvec is not kept and the section .bootpg is placed in the
4521 previous 4k of the .text section.
4523 - CONFIG_ARCH_MAP_SYSMEM
4524 Generally U-Boot (and in particular the md command) uses
4525 effective address. It is therefore not necessary to regard
4526 U-Boot address as virtual addresses that need to be translated
4527 to physical addresses. However, sandbox requires this, since
4528 it maintains its own little RAM buffer which contains all
4529 addressable memory. This option causes some memory accesses
4530 to be mapped through map_sysmem() / unmap_sysmem().
4532 - CONFIG_X86_RESET_VECTOR
4533 If defined, the x86 reset vector code is included. This is not
4534 needed when U-Boot is running from Coreboot.
4537 Defines the MPU clock speed (in MHz).
4539 NOTE : currently only supported on AM335x platforms.
4541 - CONFIG_SPL_AM33XX_ENABLE_RTC32K_OSC:
4542 Enables the RTC32K OSC on AM33xx based plattforms
4544 - CONFIG_SYS_NAND_NO_SUBPAGE_WRITE
4545 Option to disable subpage write in NAND driver
4546 driver that uses this:
4547 drivers/mtd/nand/davinci_nand.c
4549 Freescale QE/FMAN Firmware Support:
4550 -----------------------------------
4552 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
4553 loading of "firmware", which is encoded in the QE firmware binary format.
4554 This firmware often needs to be loaded during U-Boot booting, so macros
4555 are used to identify the storage device (NOR flash, SPI, etc) and the address
4558 - CONFIG_SYS_FMAN_FW_ADDR
4559 The address in the storage device where the FMAN microcode is located. The
4560 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4563 - CONFIG_SYS_QE_FW_ADDR
4564 The address in the storage device where the QE microcode is located. The
4565 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4568 - CONFIG_SYS_QE_FMAN_FW_LENGTH
4569 The maximum possible size of the firmware. The firmware binary format
4570 has a field that specifies the actual size of the firmware, but it
4571 might not be possible to read any part of the firmware unless some
4572 local storage is allocated to hold the entire firmware first.
4574 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
4575 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
4576 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
4577 virtual address in NOR flash.
4579 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
4580 Specifies that QE/FMAN firmware is located in NAND flash.
4581 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
4583 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
4584 Specifies that QE/FMAN firmware is located on the primary SD/MMC
4585 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
4587 - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
4588 Specifies that QE/FMAN firmware is located in the remote (master)
4589 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
4590 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
4591 window->master inbound window->master LAW->the ucode address in
4592 master's memory space.
4594 Freescale Layerscape Management Complex Firmware Support:
4595 ---------------------------------------------------------
4596 The Freescale Layerscape Management Complex (MC) supports the loading of
4598 This firmware often needs to be loaded during U-Boot booting, so macros
4599 are used to identify the storage device (NOR flash, SPI, etc) and the address
4602 - CONFIG_FSL_MC_ENET
4603 Enable the MC driver for Layerscape SoCs.
4605 Freescale Layerscape Debug Server Support:
4606 -------------------------------------------
4607 The Freescale Layerscape Debug Server Support supports the loading of
4608 "Debug Server firmware" and triggering SP boot-rom.
4609 This firmware often needs to be loaded during U-Boot booting.
4611 - CONFIG_SYS_MC_RSV_MEM_ALIGN
4612 Define alignment of reserved memory MC requires
4617 In order to achieve reproducible builds, timestamps used in the U-Boot build
4618 process have to be set to a fixed value.
4620 This is done using the SOURCE_DATE_EPOCH environment variable.
4621 SOURCE_DATE_EPOCH is to be set on the build host's shell, not as a configuration
4622 option for U-Boot or an environment variable in U-Boot.
4624 SOURCE_DATE_EPOCH should be set to a number of seconds since the epoch, in UTC.
4626 Building the Software:
4627 ======================
4629 Building U-Boot has been tested in several native build environments
4630 and in many different cross environments. Of course we cannot support
4631 all possibly existing versions of cross development tools in all
4632 (potentially obsolete) versions. In case of tool chain problems we
4633 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
4634 which is extensively used to build and test U-Boot.
4636 If you are not using a native environment, it is assumed that you
4637 have GNU cross compiling tools available in your path. In this case,
4638 you must set the environment variable CROSS_COMPILE in your shell.
4639 Note that no changes to the Makefile or any other source files are
4640 necessary. For example using the ELDK on a 4xx CPU, please enter:
4642 $ CROSS_COMPILE=ppc_4xx-
4643 $ export CROSS_COMPILE
4645 Note: If you wish to generate Windows versions of the utilities in
4646 the tools directory you can use the MinGW toolchain
4647 (http://www.mingw.org). Set your HOST tools to the MinGW
4648 toolchain and execute 'make tools'. For example:
4650 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
4652 Binaries such as tools/mkimage.exe will be created which can
4653 be executed on computers running Windows.
4655 U-Boot is intended to be simple to build. After installing the
4656 sources you must configure U-Boot for one specific board type. This
4661 where "NAME_defconfig" is the name of one of the existing configu-
4662 rations; see boards.cfg for supported names.
4664 Note: for some board special configuration names may exist; check if
4665 additional information is available from the board vendor; for
4666 instance, the TQM823L systems are available without (standard)
4667 or with LCD support. You can select such additional "features"
4668 when choosing the configuration, i. e.
4670 make TQM823L_defconfig
4671 - will configure for a plain TQM823L, i. e. no LCD support
4673 make TQM823L_LCD_defconfig
4674 - will configure for a TQM823L with U-Boot console on LCD
4679 Finally, type "make all", and you should get some working U-Boot
4680 images ready for download to / installation on your system:
4682 - "u-boot.bin" is a raw binary image
4683 - "u-boot" is an image in ELF binary format
4684 - "u-boot.srec" is in Motorola S-Record format
4686 By default the build is performed locally and the objects are saved
4687 in the source directory. One of the two methods can be used to change
4688 this behavior and build U-Boot to some external directory:
4690 1. Add O= to the make command line invocations:
4692 make O=/tmp/build distclean
4693 make O=/tmp/build NAME_defconfig
4694 make O=/tmp/build all
4696 2. Set environment variable KBUILD_OUTPUT to point to the desired location:
4698 export KBUILD_OUTPUT=/tmp/build
4703 Note that the command line "O=" setting overrides the KBUILD_OUTPUT environment
4707 Please be aware that the Makefiles assume you are using GNU make, so
4708 for instance on NetBSD you might need to use "gmake" instead of
4712 If the system board that you have is not listed, then you will need
4713 to port U-Boot to your hardware platform. To do this, follow these
4716 1. Create a new directory to hold your board specific code. Add any
4717 files you need. In your board directory, you will need at least
4718 the "Makefile" and a "<board>.c".
4719 2. Create a new configuration file "include/configs/<board>.h" for
4721 3. If you're porting U-Boot to a new CPU, then also create a new
4722 directory to hold your CPU specific code. Add any files you need.
4723 4. Run "make <board>_defconfig" with your new name.
4724 5. Type "make", and you should get a working "u-boot.srec" file
4725 to be installed on your target system.
4726 6. Debug and solve any problems that might arise.
4727 [Of course, this last step is much harder than it sounds.]
4730 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
4731 ==============================================================
4733 If you have modified U-Boot sources (for instance added a new board
4734 or support for new devices, a new CPU, etc.) you are expected to
4735 provide feedback to the other developers. The feedback normally takes
4736 the form of a "patch", i. e. a context diff against a certain (latest
4737 official or latest in the git repository) version of U-Boot sources.
4739 But before you submit such a patch, please verify that your modifi-
4740 cation did not break existing code. At least make sure that *ALL* of
4741 the supported boards compile WITHOUT ANY compiler warnings. To do so,
4742 just run the buildman script (tools/buildman/buildman), which will
4743 configure and build U-Boot for ALL supported system. Be warned, this
4744 will take a while. Please see the buildman README, or run 'buildman -H'
4748 See also "U-Boot Porting Guide" below.
4751 Monitor Commands - Overview:
4752 ============================
4754 go - start application at address 'addr'
4755 run - run commands in an environment variable
4756 bootm - boot application image from memory
4757 bootp - boot image via network using BootP/TFTP protocol
4758 bootz - boot zImage from memory
4759 tftpboot- boot image via network using TFTP protocol
4760 and env variables "ipaddr" and "serverip"
4761 (and eventually "gatewayip")
4762 tftpput - upload a file via network using TFTP protocol
4763 rarpboot- boot image via network using RARP/TFTP protocol
4764 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
4765 loads - load S-Record file over serial line
4766 loadb - load binary file over serial line (kermit mode)
4768 mm - memory modify (auto-incrementing)
4769 nm - memory modify (constant address)
4770 mw - memory write (fill)
4772 cmp - memory compare
4773 crc32 - checksum calculation
4774 i2c - I2C sub-system
4775 sspi - SPI utility commands
4776 base - print or set address offset
4777 printenv- print environment variables
4778 setenv - set environment variables
4779 saveenv - save environment variables to persistent storage
4780 protect - enable or disable FLASH write protection
4781 erase - erase FLASH memory
4782 flinfo - print FLASH memory information
4783 nand - NAND memory operations (see doc/README.nand)
4784 bdinfo - print Board Info structure
4785 iminfo - print header information for application image
4786 coninfo - print console devices and informations
4787 ide - IDE sub-system
4788 loop - infinite loop on address range
4789 loopw - infinite write loop on address range
4790 mtest - simple RAM test
4791 icache - enable or disable instruction cache
4792 dcache - enable or disable data cache
4793 reset - Perform RESET of the CPU
4794 echo - echo args to console
4795 version - print monitor version
4796 help - print online help
4797 ? - alias for 'help'
4800 Monitor Commands - Detailed Description:
4801 ========================================
4805 For now: just type "help <command>".
4808 Environment Variables:
4809 ======================
4811 U-Boot supports user configuration using Environment Variables which
4812 can be made persistent by saving to Flash memory.
4814 Environment Variables are set using "setenv", printed using
4815 "printenv", and saved to Flash using "saveenv". Using "setenv"
4816 without a value can be used to delete a variable from the
4817 environment. As long as you don't save the environment you are
4818 working with an in-memory copy. In case the Flash area containing the
4819 environment is erased by accident, a default environment is provided.
4821 Some configuration options can be set using Environment Variables.
4823 List of environment variables (most likely not complete):
4825 baudrate - see CONFIG_BAUDRATE
4827 bootdelay - see CONFIG_BOOTDELAY
4829 bootcmd - see CONFIG_BOOTCOMMAND
4831 bootargs - Boot arguments when booting an RTOS image
4833 bootfile - Name of the image to load with TFTP
4835 bootm_low - Memory range available for image processing in the bootm
4836 command can be restricted. This variable is given as
4837 a hexadecimal number and defines lowest address allowed
4838 for use by the bootm command. See also "bootm_size"
4839 environment variable. Address defined by "bootm_low" is
4840 also the base of the initial memory mapping for the Linux
4841 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
4844 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
4845 This variable is given as a hexadecimal number and it
4846 defines the size of the memory region starting at base
4847 address bootm_low that is accessible by the Linux kernel
4848 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
4849 as the default value if it is defined, and bootm_size is
4852 bootm_size - Memory range available for image processing in the bootm
4853 command can be restricted. This variable is given as
4854 a hexadecimal number and defines the size of the region
4855 allowed for use by the bootm command. See also "bootm_low"
4856 environment variable.
4858 updatefile - Location of the software update file on a TFTP server, used
4859 by the automatic software update feature. Please refer to
4860 documentation in doc/README.update for more details.
4862 autoload - if set to "no" (any string beginning with 'n'),
4863 "bootp" will just load perform a lookup of the
4864 configuration from the BOOTP server, but not try to
4865 load any image using TFTP
4867 autostart - if set to "yes", an image loaded using the "bootp",
4868 "rarpboot", "tftpboot" or "diskboot" commands will
4869 be automatically started (by internally calling
4872 If set to "no", a standalone image passed to the
4873 "bootm" command will be copied to the load address
4874 (and eventually uncompressed), but NOT be started.
4875 This can be used to load and uncompress arbitrary
4878 fdt_high - if set this restricts the maximum address that the
4879 flattened device tree will be copied into upon boot.
4880 For example, if you have a system with 1 GB memory
4881 at physical address 0x10000000, while Linux kernel
4882 only recognizes the first 704 MB as low memory, you
4883 may need to set fdt_high as 0x3C000000 to have the
4884 device tree blob be copied to the maximum address
4885 of the 704 MB low memory, so that Linux kernel can
4886 access it during the boot procedure.
4888 If this is set to the special value 0xFFFFFFFF then
4889 the fdt will not be copied at all on boot. For this
4890 to work it must reside in writable memory, have
4891 sufficient padding on the end of it for u-boot to
4892 add the information it needs into it, and the memory
4893 must be accessible by the kernel.
4895 fdtcontroladdr- if set this is the address of the control flattened
4896 device tree used by U-Boot when CONFIG_OF_CONTROL is
4899 i2cfast - (PPC405GP|PPC405EP only)
4900 if set to 'y' configures Linux I2C driver for fast
4901 mode (400kHZ). This environment variable is used in
4902 initialization code. So, for changes to be effective
4903 it must be saved and board must be reset.
4905 initrd_high - restrict positioning of initrd images:
4906 If this variable is not set, initrd images will be
4907 copied to the highest possible address in RAM; this
4908 is usually what you want since it allows for
4909 maximum initrd size. If for some reason you want to
4910 make sure that the initrd image is loaded below the
4911 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
4912 variable to a value of "no" or "off" or "0".
4913 Alternatively, you can set it to a maximum upper
4914 address to use (U-Boot will still check that it
4915 does not overwrite the U-Boot stack and data).
4917 For instance, when you have a system with 16 MB
4918 RAM, and want to reserve 4 MB from use by Linux,
4919 you can do this by adding "mem=12M" to the value of
4920 the "bootargs" variable. However, now you must make
4921 sure that the initrd image is placed in the first
4922 12 MB as well - this can be done with
4924 setenv initrd_high 00c00000
4926 If you set initrd_high to 0xFFFFFFFF, this is an
4927 indication to U-Boot that all addresses are legal
4928 for the Linux kernel, including addresses in flash
4929 memory. In this case U-Boot will NOT COPY the
4930 ramdisk at all. This may be useful to reduce the
4931 boot time on your system, but requires that this
4932 feature is supported by your Linux kernel.
4934 ipaddr - IP address; needed for tftpboot command
4936 loadaddr - Default load address for commands like "bootp",
4937 "rarpboot", "tftpboot", "loadb" or "diskboot"
4939 loads_echo - see CONFIG_LOADS_ECHO
4941 serverip - TFTP server IP address; needed for tftpboot command
4943 bootretry - see CONFIG_BOOT_RETRY_TIME
4945 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
4947 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
4949 ethprime - controls which interface is used first.
4951 ethact - controls which interface is currently active.
4952 For example you can do the following
4954 => setenv ethact FEC
4955 => ping 192.168.0.1 # traffic sent on FEC
4956 => setenv ethact SCC
4957 => ping 10.0.0.1 # traffic sent on SCC
4959 ethrotate - When set to "no" U-Boot does not go through all
4960 available network interfaces.
4961 It just stays at the currently selected interface.
4963 netretry - When set to "no" each network operation will
4964 either succeed or fail without retrying.
4965 When set to "once" the network operation will
4966 fail when all the available network interfaces
4967 are tried once without success.
4968 Useful on scripts which control the retry operation
4971 npe_ucode - set load address for the NPE microcode
4973 silent_linux - If set then Linux will be told to boot silently, by
4974 changing the console to be empty. If "yes" it will be
4975 made silent. If "no" it will not be made silent. If
4976 unset, then it will be made silent if the U-Boot console
4979 tftpsrcp - If this is set, the value is used for TFTP's
4982 tftpdstp - If this is set, the value is used for TFTP's UDP
4983 destination port instead of the Well Know Port 69.
4985 tftpblocksize - Block size to use for TFTP transfers; if not set,
4986 we use the TFTP server's default block size
4988 tftptimeout - Retransmission timeout for TFTP packets (in milli-
4989 seconds, minimum value is 1000 = 1 second). Defines
4990 when a packet is considered to be lost so it has to
4991 be retransmitted. The default is 5000 = 5 seconds.
4992 Lowering this value may make downloads succeed
4993 faster in networks with high packet loss rates or
4994 with unreliable TFTP servers.
4996 tftptimeoutcountmax - maximum count of TFTP timeouts (no
4997 unit, minimum value = 0). Defines how many timeouts
4998 can happen during a single file transfer before that
4999 transfer is aborted. The default is 10, and 0 means
5000 'no timeouts allowed'. Increasing this value may help
5001 downloads succeed with high packet loss rates, or with
5002 unreliable TFTP servers or client hardware.
5004 vlan - When set to a value < 4095 the traffic over
5005 Ethernet is encapsulated/received over 802.1q
5008 bootpretryperiod - Period during which BOOTP/DHCP sends retries.
5009 Unsigned value, in milliseconds. If not set, the period will
5010 be either the default (28000), or a value based on
5011 CONFIG_NET_RETRY_COUNT, if defined. This value has
5012 precedence over the valu based on CONFIG_NET_RETRY_COUNT.
5014 The following image location variables contain the location of images
5015 used in booting. The "Image" column gives the role of the image and is
5016 not an environment variable name. The other columns are environment
5017 variable names. "File Name" gives the name of the file on a TFTP
5018 server, "RAM Address" gives the location in RAM the image will be
5019 loaded to, and "Flash Location" gives the image's address in NOR
5020 flash or offset in NAND flash.
5022 *Note* - these variables don't have to be defined for all boards, some
5023 boards currently use other variables for these purposes, and some
5024 boards use these variables for other purposes.
5026 Image File Name RAM Address Flash Location
5027 ----- --------- ----------- --------------
5028 u-boot u-boot u-boot_addr_r u-boot_addr
5029 Linux kernel bootfile kernel_addr_r kernel_addr
5030 device tree blob fdtfile fdt_addr_r fdt_addr
5031 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
5033 The following environment variables may be used and automatically
5034 updated by the network boot commands ("bootp" and "rarpboot"),
5035 depending the information provided by your boot server:
5037 bootfile - see above
5038 dnsip - IP address of your Domain Name Server
5039 dnsip2 - IP address of your secondary Domain Name Server
5040 gatewayip - IP address of the Gateway (Router) to use
5041 hostname - Target hostname
5043 netmask - Subnet Mask
5044 rootpath - Pathname of the root filesystem on the NFS server
5045 serverip - see above
5048 There are two special Environment Variables:
5050 serial# - contains hardware identification information such
5051 as type string and/or serial number
5052 ethaddr - Ethernet address
5054 These variables can be set only once (usually during manufacturing of
5055 the board). U-Boot refuses to delete or overwrite these variables
5056 once they have been set once.
5059 Further special Environment Variables:
5061 ver - Contains the U-Boot version string as printed
5062 with the "version" command. This variable is
5063 readonly (see CONFIG_VERSION_VARIABLE).
5066 Please note that changes to some configuration parameters may take
5067 only effect after the next boot (yes, that's just like Windoze :-).
5070 Callback functions for environment variables:
5071 ---------------------------------------------
5073 For some environment variables, the behavior of u-boot needs to change
5074 when their values are changed. This functionality allows functions to
5075 be associated with arbitrary variables. On creation, overwrite, or
5076 deletion, the callback will provide the opportunity for some side
5077 effect to happen or for the change to be rejected.
5079 The callbacks are named and associated with a function using the
5080 U_BOOT_ENV_CALLBACK macro in your board or driver code.
5082 These callbacks are associated with variables in one of two ways. The
5083 static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC
5084 in the board configuration to a string that defines a list of
5085 associations. The list must be in the following format:
5087 entry = variable_name[:callback_name]
5090 If the callback name is not specified, then the callback is deleted.
5091 Spaces are also allowed anywhere in the list.
5093 Callbacks can also be associated by defining the ".callbacks" variable
5094 with the same list format above. Any association in ".callbacks" will
5095 override any association in the static list. You can define
5096 CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the
5097 ".callbacks" environment variable in the default or embedded environment.
5099 If CONFIG_REGEX is defined, the variable_name above is evaluated as a
5100 regular expression. This allows multiple variables to be connected to
5101 the same callback without explicitly listing them all out.
5104 Command Line Parsing:
5105 =====================
5107 There are two different command line parsers available with U-Boot:
5108 the old "simple" one, and the much more powerful "hush" shell:
5110 Old, simple command line parser:
5111 --------------------------------
5113 - supports environment variables (through setenv / saveenv commands)
5114 - several commands on one line, separated by ';'
5115 - variable substitution using "... ${name} ..." syntax
5116 - special characters ('$', ';') can be escaped by prefixing with '\',
5118 setenv bootcmd bootm \${address}
5119 - You can also escape text by enclosing in single apostrophes, for example:
5120 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
5125 - similar to Bourne shell, with control structures like
5126 if...then...else...fi, for...do...done; while...do...done,
5127 until...do...done, ...
5128 - supports environment ("global") variables (through setenv / saveenv
5129 commands) and local shell variables (through standard shell syntax
5130 "name=value"); only environment variables can be used with "run"
5136 (1) If a command line (or an environment variable executed by a "run"
5137 command) contains several commands separated by semicolon, and
5138 one of these commands fails, then the remaining commands will be
5141 (2) If you execute several variables with one call to run (i. e.
5142 calling run with a list of variables as arguments), any failing
5143 command will cause "run" to terminate, i. e. the remaining
5144 variables are not executed.
5146 Note for Redundant Ethernet Interfaces:
5147 =======================================
5149 Some boards come with redundant Ethernet interfaces; U-Boot supports
5150 such configurations and is capable of automatic selection of a
5151 "working" interface when needed. MAC assignment works as follows:
5153 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
5154 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
5155 "eth1addr" (=>eth1), "eth2addr", ...
5157 If the network interface stores some valid MAC address (for instance
5158 in SROM), this is used as default address if there is NO correspon-
5159 ding setting in the environment; if the corresponding environment
5160 variable is set, this overrides the settings in the card; that means:
5162 o If the SROM has a valid MAC address, and there is no address in the
5163 environment, the SROM's address is used.
5165 o If there is no valid address in the SROM, and a definition in the
5166 environment exists, then the value from the environment variable is
5169 o If both the SROM and the environment contain a MAC address, and
5170 both addresses are the same, this MAC address is used.
5172 o If both the SROM and the environment contain a MAC address, and the
5173 addresses differ, the value from the environment is used and a
5176 o If neither SROM nor the environment contain a MAC address, an error
5177 is raised. If CONFIG_NET_RANDOM_ETHADDR is defined, then in this case
5178 a random, locally-assigned MAC is used.
5180 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
5181 will be programmed into hardware as part of the initialization process. This
5182 may be skipped by setting the appropriate 'ethmacskip' environment variable.
5183 The naming convention is as follows:
5184 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
5189 U-Boot is capable of booting (and performing other auxiliary operations on)
5190 images in two formats:
5192 New uImage format (FIT)
5193 -----------------------
5195 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
5196 to Flattened Device Tree). It allows the use of images with multiple
5197 components (several kernels, ramdisks, etc.), with contents protected by
5198 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
5204 Old image format is based on binary files which can be basically anything,
5205 preceded by a special header; see the definitions in include/image.h for
5206 details; basically, the header defines the following image properties:
5208 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
5209 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
5210 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
5211 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
5213 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
5214 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
5215 Currently supported: ARM, AVR32, Intel x86, MIPS, NDS32, Nios II, PowerPC).
5216 * Compression Type (uncompressed, gzip, bzip2)
5222 The header is marked by a special Magic Number, and both the header
5223 and the data portions of the image are secured against corruption by
5230 Although U-Boot should support any OS or standalone application
5231 easily, the main focus has always been on Linux during the design of
5234 U-Boot includes many features that so far have been part of some
5235 special "boot loader" code within the Linux kernel. Also, any
5236 "initrd" images to be used are no longer part of one big Linux image;
5237 instead, kernel and "initrd" are separate images. This implementation
5238 serves several purposes:
5240 - the same features can be used for other OS or standalone
5241 applications (for instance: using compressed images to reduce the
5242 Flash memory footprint)
5244 - it becomes much easier to port new Linux kernel versions because
5245 lots of low-level, hardware dependent stuff are done by U-Boot
5247 - the same Linux kernel image can now be used with different "initrd"
5248 images; of course this also means that different kernel images can
5249 be run with the same "initrd". This makes testing easier (you don't
5250 have to build a new "zImage.initrd" Linux image when you just
5251 change a file in your "initrd"). Also, a field-upgrade of the
5252 software is easier now.
5258 Porting Linux to U-Boot based systems:
5259 ---------------------------------------
5261 U-Boot cannot save you from doing all the necessary modifications to
5262 configure the Linux device drivers for use with your target hardware
5263 (no, we don't intend to provide a full virtual machine interface to
5266 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
5268 Just make sure your machine specific header file (for instance
5269 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
5270 Information structure as we define in include/asm-<arch>/u-boot.h,
5271 and make sure that your definition of IMAP_ADDR uses the same value
5272 as your U-Boot configuration in CONFIG_SYS_IMMR.
5274 Note that U-Boot now has a driver model, a unified model for drivers.
5275 If you are adding a new driver, plumb it into driver model. If there
5276 is no uclass available, you are encouraged to create one. See
5280 Configuring the Linux kernel:
5281 -----------------------------
5283 No specific requirements for U-Boot. Make sure you have some root
5284 device (initial ramdisk, NFS) for your target system.
5287 Building a Linux Image:
5288 -----------------------
5290 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
5291 not used. If you use recent kernel source, a new build target
5292 "uImage" will exist which automatically builds an image usable by
5293 U-Boot. Most older kernels also have support for a "pImage" target,
5294 which was introduced for our predecessor project PPCBoot and uses a
5295 100% compatible format.
5299 make TQM850L_defconfig
5304 The "uImage" build target uses a special tool (in 'tools/mkimage') to
5305 encapsulate a compressed Linux kernel image with header information,
5306 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
5308 * build a standard "vmlinux" kernel image (in ELF binary format):
5310 * convert the kernel into a raw binary image:
5312 ${CROSS_COMPILE}-objcopy -O binary \
5313 -R .note -R .comment \
5314 -S vmlinux linux.bin
5316 * compress the binary image:
5320 * package compressed binary image for U-Boot:
5322 mkimage -A ppc -O linux -T kernel -C gzip \
5323 -a 0 -e 0 -n "Linux Kernel Image" \
5324 -d linux.bin.gz uImage
5327 The "mkimage" tool can also be used to create ramdisk images for use
5328 with U-Boot, either separated from the Linux kernel image, or
5329 combined into one file. "mkimage" encapsulates the images with a 64
5330 byte header containing information about target architecture,
5331 operating system, image type, compression method, entry points, time
5332 stamp, CRC32 checksums, etc.
5334 "mkimage" can be called in two ways: to verify existing images and
5335 print the header information, or to build new images.
5337 In the first form (with "-l" option) mkimage lists the information
5338 contained in the header of an existing U-Boot image; this includes
5339 checksum verification:
5341 tools/mkimage -l image
5342 -l ==> list image header information
5344 The second form (with "-d" option) is used to build a U-Boot image
5345 from a "data file" which is used as image payload:
5347 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
5348 -n name -d data_file image
5349 -A ==> set architecture to 'arch'
5350 -O ==> set operating system to 'os'
5351 -T ==> set image type to 'type'
5352 -C ==> set compression type 'comp'
5353 -a ==> set load address to 'addr' (hex)
5354 -e ==> set entry point to 'ep' (hex)
5355 -n ==> set image name to 'name'
5356 -d ==> use image data from 'datafile'
5358 Right now, all Linux kernels for PowerPC systems use the same load
5359 address (0x00000000), but the entry point address depends on the
5362 - 2.2.x kernels have the entry point at 0x0000000C,
5363 - 2.3.x and later kernels have the entry point at 0x00000000.
5365 So a typical call to build a U-Boot image would read:
5367 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5368 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
5369 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
5370 > examples/uImage.TQM850L
5371 Image Name: 2.4.4 kernel for TQM850L
5372 Created: Wed Jul 19 02:34:59 2000
5373 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5374 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5375 Load Address: 0x00000000
5376 Entry Point: 0x00000000
5378 To verify the contents of the image (or check for corruption):
5380 -> tools/mkimage -l examples/uImage.TQM850L
5381 Image Name: 2.4.4 kernel for TQM850L
5382 Created: Wed Jul 19 02:34:59 2000
5383 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5384 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5385 Load Address: 0x00000000
5386 Entry Point: 0x00000000
5388 NOTE: for embedded systems where boot time is critical you can trade
5389 speed for memory and install an UNCOMPRESSED image instead: this
5390 needs more space in Flash, but boots much faster since it does not
5391 need to be uncompressed:
5393 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
5394 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5395 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
5396 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
5397 > examples/uImage.TQM850L-uncompressed
5398 Image Name: 2.4.4 kernel for TQM850L
5399 Created: Wed Jul 19 02:34:59 2000
5400 Image Type: PowerPC Linux Kernel Image (uncompressed)
5401 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
5402 Load Address: 0x00000000
5403 Entry Point: 0x00000000
5406 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
5407 when your kernel is intended to use an initial ramdisk:
5409 -> tools/mkimage -n 'Simple Ramdisk Image' \
5410 > -A ppc -O linux -T ramdisk -C gzip \
5411 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
5412 Image Name: Simple Ramdisk Image
5413 Created: Wed Jan 12 14:01:50 2000
5414 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5415 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
5416 Load Address: 0x00000000
5417 Entry Point: 0x00000000
5419 The "dumpimage" is a tool to disassemble images built by mkimage. Its "-i"
5420 option performs the converse operation of the mkimage's second form (the "-d"
5421 option). Given an image built by mkimage, the dumpimage extracts a "data file"
5424 tools/dumpimage -i image -T type -p position data_file
5425 -i ==> extract from the 'image' a specific 'data_file'
5426 -T ==> set image type to 'type'
5427 -p ==> 'position' (starting at 0) of the 'data_file' inside the 'image'
5430 Installing a Linux Image:
5431 -------------------------
5433 To downloading a U-Boot image over the serial (console) interface,
5434 you must convert the image to S-Record format:
5436 objcopy -I binary -O srec examples/image examples/image.srec
5438 The 'objcopy' does not understand the information in the U-Boot
5439 image header, so the resulting S-Record file will be relative to
5440 address 0x00000000. To load it to a given address, you need to
5441 specify the target address as 'offset' parameter with the 'loads'
5444 Example: install the image to address 0x40100000 (which on the
5445 TQM8xxL is in the first Flash bank):
5447 => erase 40100000 401FFFFF
5453 ## Ready for S-Record download ...
5454 ~>examples/image.srec
5455 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
5457 15989 15990 15991 15992
5458 [file transfer complete]
5460 ## Start Addr = 0x00000000
5463 You can check the success of the download using the 'iminfo' command;
5464 this includes a checksum verification so you can be sure no data
5465 corruption happened:
5469 ## Checking Image at 40100000 ...
5470 Image Name: 2.2.13 for initrd on TQM850L
5471 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5472 Data Size: 335725 Bytes = 327 kB = 0 MB
5473 Load Address: 00000000
5474 Entry Point: 0000000c
5475 Verifying Checksum ... OK
5481 The "bootm" command is used to boot an application that is stored in
5482 memory (RAM or Flash). In case of a Linux kernel image, the contents
5483 of the "bootargs" environment variable is passed to the kernel as
5484 parameters. You can check and modify this variable using the
5485 "printenv" and "setenv" commands:
5488 => printenv bootargs
5489 bootargs=root=/dev/ram
5491 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5493 => printenv bootargs
5494 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5497 ## Booting Linux kernel at 40020000 ...
5498 Image Name: 2.2.13 for NFS on TQM850L
5499 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5500 Data Size: 381681 Bytes = 372 kB = 0 MB
5501 Load Address: 00000000
5502 Entry Point: 0000000c
5503 Verifying Checksum ... OK
5504 Uncompressing Kernel Image ... OK
5505 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
5506 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5507 time_init: decrementer frequency = 187500000/60
5508 Calibrating delay loop... 49.77 BogoMIPS
5509 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
5512 If you want to boot a Linux kernel with initial RAM disk, you pass
5513 the memory addresses of both the kernel and the initrd image (PPBCOOT
5514 format!) to the "bootm" command:
5516 => imi 40100000 40200000
5518 ## Checking Image at 40100000 ...
5519 Image Name: 2.2.13 for initrd on TQM850L
5520 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5521 Data Size: 335725 Bytes = 327 kB = 0 MB
5522 Load Address: 00000000
5523 Entry Point: 0000000c
5524 Verifying Checksum ... OK
5526 ## Checking Image at 40200000 ...
5527 Image Name: Simple Ramdisk Image
5528 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5529 Data Size: 566530 Bytes = 553 kB = 0 MB
5530 Load Address: 00000000
5531 Entry Point: 00000000
5532 Verifying Checksum ... OK
5534 => bootm 40100000 40200000
5535 ## Booting Linux kernel at 40100000 ...
5536 Image Name: 2.2.13 for initrd on TQM850L
5537 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5538 Data Size: 335725 Bytes = 327 kB = 0 MB
5539 Load Address: 00000000
5540 Entry Point: 0000000c
5541 Verifying Checksum ... OK
5542 Uncompressing Kernel Image ... OK
5543 ## Loading RAMDisk Image at 40200000 ...
5544 Image Name: Simple Ramdisk Image
5545 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5546 Data Size: 566530 Bytes = 553 kB = 0 MB
5547 Load Address: 00000000
5548 Entry Point: 00000000
5549 Verifying Checksum ... OK
5550 Loading Ramdisk ... OK
5551 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
5552 Boot arguments: root=/dev/ram
5553 time_init: decrementer frequency = 187500000/60
5554 Calibrating delay loop... 49.77 BogoMIPS
5556 RAMDISK: Compressed image found at block 0
5557 VFS: Mounted root (ext2 filesystem).
5561 Boot Linux and pass a flat device tree:
5564 First, U-Boot must be compiled with the appropriate defines. See the section
5565 titled "Linux Kernel Interface" above for a more in depth explanation. The
5566 following is an example of how to start a kernel and pass an updated
5572 oft=oftrees/mpc8540ads.dtb
5573 => tftp $oftaddr $oft
5574 Speed: 1000, full duplex
5576 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
5577 Filename 'oftrees/mpc8540ads.dtb'.
5578 Load address: 0x300000
5581 Bytes transferred = 4106 (100a hex)
5582 => tftp $loadaddr $bootfile
5583 Speed: 1000, full duplex
5585 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
5587 Load address: 0x200000
5588 Loading:############
5590 Bytes transferred = 1029407 (fb51f hex)
5595 => bootm $loadaddr - $oftaddr
5596 ## Booting image at 00200000 ...
5597 Image Name: Linux-2.6.17-dirty
5598 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5599 Data Size: 1029343 Bytes = 1005.2 kB
5600 Load Address: 00000000
5601 Entry Point: 00000000
5602 Verifying Checksum ... OK
5603 Uncompressing Kernel Image ... OK
5604 Booting using flat device tree at 0x300000
5605 Using MPC85xx ADS machine description
5606 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
5610 More About U-Boot Image Types:
5611 ------------------------------
5613 U-Boot supports the following image types:
5615 "Standalone Programs" are directly runnable in the environment
5616 provided by U-Boot; it is expected that (if they behave
5617 well) you can continue to work in U-Boot after return from
5618 the Standalone Program.
5619 "OS Kernel Images" are usually images of some Embedded OS which
5620 will take over control completely. Usually these programs
5621 will install their own set of exception handlers, device
5622 drivers, set up the MMU, etc. - this means, that you cannot
5623 expect to re-enter U-Boot except by resetting the CPU.
5624 "RAMDisk Images" are more or less just data blocks, and their
5625 parameters (address, size) are passed to an OS kernel that is
5627 "Multi-File Images" contain several images, typically an OS
5628 (Linux) kernel image and one or more data images like
5629 RAMDisks. This construct is useful for instance when you want
5630 to boot over the network using BOOTP etc., where the boot
5631 server provides just a single image file, but you want to get
5632 for instance an OS kernel and a RAMDisk image.
5634 "Multi-File Images" start with a list of image sizes, each
5635 image size (in bytes) specified by an "uint32_t" in network
5636 byte order. This list is terminated by an "(uint32_t)0".
5637 Immediately after the terminating 0 follow the images, one by
5638 one, all aligned on "uint32_t" boundaries (size rounded up to
5639 a multiple of 4 bytes).
5641 "Firmware Images" are binary images containing firmware (like
5642 U-Boot or FPGA images) which usually will be programmed to
5645 "Script files" are command sequences that will be executed by
5646 U-Boot's command interpreter; this feature is especially
5647 useful when you configure U-Boot to use a real shell (hush)
5648 as command interpreter.
5650 Booting the Linux zImage:
5651 -------------------------
5653 On some platforms, it's possible to boot Linux zImage. This is done
5654 using the "bootz" command. The syntax of "bootz" command is the same
5655 as the syntax of "bootm" command.
5657 Note, defining the CONFIG_SUPPORT_RAW_INITRD allows user to supply
5658 kernel with raw initrd images. The syntax is slightly different, the
5659 address of the initrd must be augmented by it's size, in the following
5660 format: "<initrd addres>:<initrd size>".
5666 One of the features of U-Boot is that you can dynamically load and
5667 run "standalone" applications, which can use some resources of
5668 U-Boot like console I/O functions or interrupt services.
5670 Two simple examples are included with the sources:
5675 'examples/hello_world.c' contains a small "Hello World" Demo
5676 application; it is automatically compiled when you build U-Boot.
5677 It's configured to run at address 0x00040004, so you can play with it
5681 ## Ready for S-Record download ...
5682 ~>examples/hello_world.srec
5683 1 2 3 4 5 6 7 8 9 10 11 ...
5684 [file transfer complete]
5686 ## Start Addr = 0x00040004
5688 => go 40004 Hello World! This is a test.
5689 ## Starting application at 0x00040004 ...
5700 Hit any key to exit ...
5702 ## Application terminated, rc = 0x0
5704 Another example, which demonstrates how to register a CPM interrupt
5705 handler with the U-Boot code, can be found in 'examples/timer.c'.
5706 Here, a CPM timer is set up to generate an interrupt every second.
5707 The interrupt service routine is trivial, just printing a '.'
5708 character, but this is just a demo program. The application can be
5709 controlled by the following keys:
5711 ? - print current values og the CPM Timer registers
5712 b - enable interrupts and start timer
5713 e - stop timer and disable interrupts
5714 q - quit application
5717 ## Ready for S-Record download ...
5718 ~>examples/timer.srec
5719 1 2 3 4 5 6 7 8 9 10 11 ...
5720 [file transfer complete]
5722 ## Start Addr = 0x00040004
5725 ## Starting application at 0x00040004 ...
5728 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
5731 [q, b, e, ?] Set interval 1000000 us
5734 [q, b, e, ?] ........
5735 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
5738 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
5741 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
5744 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
5746 [q, b, e, ?] ...Stopping timer
5748 [q, b, e, ?] ## Application terminated, rc = 0x0
5754 Over time, many people have reported problems when trying to use the
5755 "minicom" terminal emulation program for serial download. I (wd)
5756 consider minicom to be broken, and recommend not to use it. Under
5757 Unix, I recommend to use C-Kermit for general purpose use (and
5758 especially for kermit binary protocol download ("loadb" command), and
5759 use "cu" for S-Record download ("loads" command). See
5760 http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
5761 for help with kermit.
5764 Nevertheless, if you absolutely want to use it try adding this
5765 configuration to your "File transfer protocols" section:
5767 Name Program Name U/D FullScr IO-Red. Multi
5768 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
5769 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
5775 Starting at version 0.9.2, U-Boot supports NetBSD both as host
5776 (build U-Boot) and target system (boots NetBSD/mpc8xx).
5778 Building requires a cross environment; it is known to work on
5779 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
5780 need gmake since the Makefiles are not compatible with BSD make).
5781 Note that the cross-powerpc package does not install include files;
5782 attempting to build U-Boot will fail because <machine/ansi.h> is
5783 missing. This file has to be installed and patched manually:
5785 # cd /usr/pkg/cross/powerpc-netbsd/include
5787 # ln -s powerpc machine
5788 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
5789 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
5791 Native builds *don't* work due to incompatibilities between native
5792 and U-Boot include files.
5794 Booting assumes that (the first part of) the image booted is a
5795 stage-2 loader which in turn loads and then invokes the kernel
5796 proper. Loader sources will eventually appear in the NetBSD source
5797 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
5798 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
5801 Implementation Internals:
5802 =========================
5804 The following is not intended to be a complete description of every
5805 implementation detail. However, it should help to understand the
5806 inner workings of U-Boot and make it easier to port it to custom
5810 Initial Stack, Global Data:
5811 ---------------------------
5813 The implementation of U-Boot is complicated by the fact that U-Boot
5814 starts running out of ROM (flash memory), usually without access to
5815 system RAM (because the memory controller is not initialized yet).
5816 This means that we don't have writable Data or BSS segments, and BSS
5817 is not initialized as zero. To be able to get a C environment working
5818 at all, we have to allocate at least a minimal stack. Implementation
5819 options for this are defined and restricted by the CPU used: Some CPU
5820 models provide on-chip memory (like the IMMR area on MPC8xx and
5821 MPC826x processors), on others (parts of) the data cache can be
5822 locked as (mis-) used as memory, etc.
5824 Chris Hallinan posted a good summary of these issues to the
5825 U-Boot mailing list:
5827 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
5828 From: "Chris Hallinan" <clh@net1plus.com>
5829 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
5832 Correct me if I'm wrong, folks, but the way I understand it
5833 is this: Using DCACHE as initial RAM for Stack, etc, does not
5834 require any physical RAM backing up the cache. The cleverness
5835 is that the cache is being used as a temporary supply of
5836 necessary storage before the SDRAM controller is setup. It's
5837 beyond the scope of this list to explain the details, but you
5838 can see how this works by studying the cache architecture and
5839 operation in the architecture and processor-specific manuals.
5841 OCM is On Chip Memory, which I believe the 405GP has 4K. It
5842 is another option for the system designer to use as an
5843 initial stack/RAM area prior to SDRAM being available. Either
5844 option should work for you. Using CS 4 should be fine if your
5845 board designers haven't used it for something that would
5846 cause you grief during the initial boot! It is frequently not
5849 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
5850 with your processor/board/system design. The default value
5851 you will find in any recent u-boot distribution in
5852 walnut.h should work for you. I'd set it to a value larger
5853 than your SDRAM module. If you have a 64MB SDRAM module, set
5854 it above 400_0000. Just make sure your board has no resources
5855 that are supposed to respond to that address! That code in
5856 start.S has been around a while and should work as is when
5857 you get the config right.
5862 It is essential to remember this, since it has some impact on the C
5863 code for the initialization procedures:
5865 * Initialized global data (data segment) is read-only. Do not attempt
5868 * Do not use any uninitialized global data (or implicitly initialized
5869 as zero data - BSS segment) at all - this is undefined, initiali-
5870 zation is performed later (when relocating to RAM).
5872 * Stack space is very limited. Avoid big data buffers or things like
5875 Having only the stack as writable memory limits means we cannot use
5876 normal global data to share information between the code. But it
5877 turned out that the implementation of U-Boot can be greatly
5878 simplified by making a global data structure (gd_t) available to all
5879 functions. We could pass a pointer to this data as argument to _all_
5880 functions, but this would bloat the code. Instead we use a feature of
5881 the GCC compiler (Global Register Variables) to share the data: we
5882 place a pointer (gd) to the global data into a register which we
5883 reserve for this purpose.
5885 When choosing a register for such a purpose we are restricted by the
5886 relevant (E)ABI specifications for the current architecture, and by
5887 GCC's implementation.
5889 For PowerPC, the following registers have specific use:
5891 R2: reserved for system use
5892 R3-R4: parameter passing and return values
5893 R5-R10: parameter passing
5894 R13: small data area pointer
5898 (U-Boot also uses R12 as internal GOT pointer. r12
5899 is a volatile register so r12 needs to be reset when
5900 going back and forth between asm and C)
5902 ==> U-Boot will use R2 to hold a pointer to the global data
5904 Note: on PPC, we could use a static initializer (since the
5905 address of the global data structure is known at compile time),
5906 but it turned out that reserving a register results in somewhat
5907 smaller code - although the code savings are not that big (on
5908 average for all boards 752 bytes for the whole U-Boot image,
5909 624 text + 127 data).
5911 On ARM, the following registers are used:
5913 R0: function argument word/integer result
5914 R1-R3: function argument word
5915 R9: platform specific
5916 R10: stack limit (used only if stack checking is enabled)
5917 R11: argument (frame) pointer
5918 R12: temporary workspace
5921 R15: program counter
5923 ==> U-Boot will use R9 to hold a pointer to the global data
5925 Note: on ARM, only R_ARM_RELATIVE relocations are supported.
5927 On Nios II, the ABI is documented here:
5928 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
5930 ==> U-Boot will use gp to hold a pointer to the global data
5932 Note: on Nios II, we give "-G0" option to gcc and don't use gp
5933 to access small data sections, so gp is free.
5935 On NDS32, the following registers are used:
5937 R0-R1: argument/return
5939 R15: temporary register for assembler
5940 R16: trampoline register
5941 R28: frame pointer (FP)
5942 R29: global pointer (GP)
5943 R30: link register (LP)
5944 R31: stack pointer (SP)
5945 PC: program counter (PC)
5947 ==> U-Boot will use R10 to hold a pointer to the global data
5949 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
5950 or current versions of GCC may "optimize" the code too much.
5955 U-Boot runs in system state and uses physical addresses, i.e. the
5956 MMU is not used either for address mapping nor for memory protection.
5958 The available memory is mapped to fixed addresses using the memory
5959 controller. In this process, a contiguous block is formed for each
5960 memory type (Flash, SDRAM, SRAM), even when it consists of several
5961 physical memory banks.
5963 U-Boot is installed in the first 128 kB of the first Flash bank (on
5964 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
5965 booting and sizing and initializing DRAM, the code relocates itself
5966 to the upper end of DRAM. Immediately below the U-Boot code some
5967 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
5968 configuration setting]. Below that, a structure with global Board
5969 Info data is placed, followed by the stack (growing downward).
5971 Additionally, some exception handler code is copied to the low 8 kB
5972 of DRAM (0x00000000 ... 0x00001FFF).
5974 So a typical memory configuration with 16 MB of DRAM could look like
5977 0x0000 0000 Exception Vector code
5980 0x0000 2000 Free for Application Use
5986 0x00FB FF20 Monitor Stack (Growing downward)
5987 0x00FB FFAC Board Info Data and permanent copy of global data
5988 0x00FC 0000 Malloc Arena
5991 0x00FE 0000 RAM Copy of Monitor Code
5992 ... eventually: LCD or video framebuffer
5993 ... eventually: pRAM (Protected RAM - unchanged by reset)
5994 0x00FF FFFF [End of RAM]
5997 System Initialization:
5998 ----------------------
6000 In the reset configuration, U-Boot starts at the reset entry point
6001 (on most PowerPC systems at address 0x00000100). Because of the reset
6002 configuration for CS0# this is a mirror of the on board Flash memory.
6003 To be able to re-map memory U-Boot then jumps to its link address.
6004 To be able to implement the initialization code in C, a (small!)
6005 initial stack is set up in the internal Dual Ported RAM (in case CPUs
6006 which provide such a feature like MPC8xx or MPC8260), or in a locked
6007 part of the data cache. After that, U-Boot initializes the CPU core,
6008 the caches and the SIU.
6010 Next, all (potentially) available memory banks are mapped using a
6011 preliminary mapping. For example, we put them on 512 MB boundaries
6012 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
6013 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
6014 programmed for SDRAM access. Using the temporary configuration, a
6015 simple memory test is run that determines the size of the SDRAM
6018 When there is more than one SDRAM bank, and the banks are of
6019 different size, the largest is mapped first. For equal size, the first
6020 bank (CS2#) is mapped first. The first mapping is always for address
6021 0x00000000, with any additional banks following immediately to create
6022 contiguous memory starting from 0.
6024 Then, the monitor installs itself at the upper end of the SDRAM area
6025 and allocates memory for use by malloc() and for the global Board
6026 Info data; also, the exception vector code is copied to the low RAM
6027 pages, and the final stack is set up.
6029 Only after this relocation will you have a "normal" C environment;
6030 until that you are restricted in several ways, mostly because you are
6031 running from ROM, and because the code will have to be relocated to a
6035 U-Boot Porting Guide:
6036 ----------------------
6038 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
6042 int main(int argc, char *argv[])
6044 sighandler_t no_more_time;
6046 signal(SIGALRM, no_more_time);
6047 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
6049 if (available_money > available_manpower) {
6050 Pay consultant to port U-Boot;
6054 Download latest U-Boot source;
6056 Subscribe to u-boot mailing list;
6059 email("Hi, I am new to U-Boot, how do I get started?");
6062 Read the README file in the top level directory;
6063 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
6064 Read applicable doc/*.README;
6065 Read the source, Luke;
6066 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
6069 if (available_money > toLocalCurrency ($2500))
6072 Add a lot of aggravation and time;
6074 if (a similar board exists) { /* hopefully... */
6075 cp -a board/<similar> board/<myboard>
6076 cp include/configs/<similar>.h include/configs/<myboard>.h
6078 Create your own board support subdirectory;
6079 Create your own board include/configs/<myboard>.h file;
6081 Edit new board/<myboard> files
6082 Edit new include/configs/<myboard>.h
6087 Add / modify source code;
6091 email("Hi, I am having problems...");
6093 Send patch file to the U-Boot email list;
6094 if (reasonable critiques)
6095 Incorporate improvements from email list code review;
6097 Defend code as written;
6103 void no_more_time (int sig)
6112 All contributions to U-Boot should conform to the Linux kernel
6113 coding style; see the file "Documentation/CodingStyle" and the script
6114 "scripts/Lindent" in your Linux kernel source directory.
6116 Source files originating from a different project (for example the
6117 MTD subsystem) are generally exempt from these guidelines and are not
6118 reformatted to ease subsequent migration to newer versions of those
6121 Please note that U-Boot is implemented in C (and to some small parts in
6122 Assembler); no C++ is used, so please do not use C++ style comments (//)
6125 Please also stick to the following formatting rules:
6126 - remove any trailing white space
6127 - use TAB characters for indentation and vertical alignment, not spaces
6128 - make sure NOT to use DOS '\r\n' line feeds
6129 - do not add more than 2 consecutive empty lines to source files
6130 - do not add trailing empty lines to source files
6132 Submissions which do not conform to the standards may be returned
6133 with a request to reformat the changes.
6139 Since the number of patches for U-Boot is growing, we need to
6140 establish some rules. Submissions which do not conform to these rules
6141 may be rejected, even when they contain important and valuable stuff.
6143 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
6145 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
6146 see http://lists.denx.de/mailman/listinfo/u-boot
6148 When you send a patch, please include the following information with
6151 * For bug fixes: a description of the bug and how your patch fixes
6152 this bug. Please try to include a way of demonstrating that the
6153 patch actually fixes something.
6155 * For new features: a description of the feature and your
6158 * A CHANGELOG entry as plaintext (separate from the patch)
6160 * For major contributions, add a MAINTAINERS file with your
6161 information and associated file and directory references.
6163 * When you add support for a new board, don't forget to add a
6164 maintainer e-mail address to the boards.cfg file, too.
6166 * If your patch adds new configuration options, don't forget to
6167 document these in the README file.
6169 * The patch itself. If you are using git (which is *strongly*
6170 recommended) you can easily generate the patch using the
6171 "git format-patch". If you then use "git send-email" to send it to
6172 the U-Boot mailing list, you will avoid most of the common problems
6173 with some other mail clients.
6175 If you cannot use git, use "diff -purN OLD NEW". If your version of
6176 diff does not support these options, then get the latest version of
6179 The current directory when running this command shall be the parent
6180 directory of the U-Boot source tree (i. e. please make sure that
6181 your patch includes sufficient directory information for the
6184 We prefer patches as plain text. MIME attachments are discouraged,
6185 and compressed attachments must not be used.
6187 * If one logical set of modifications affects or creates several
6188 files, all these changes shall be submitted in a SINGLE patch file.
6190 * Changesets that contain different, unrelated modifications shall be
6191 submitted as SEPARATE patches, one patch per changeset.
6196 * Before sending the patch, run the buildman script on your patched
6197 source tree and make sure that no errors or warnings are reported
6198 for any of the boards.
6200 * Keep your modifications to the necessary minimum: A patch
6201 containing several unrelated changes or arbitrary reformats will be
6202 returned with a request to re-formatting / split it.
6204 * If you modify existing code, make sure that your new code does not
6205 add to the memory footprint of the code ;-) Small is beautiful!
6206 When adding new features, these should compile conditionally only
6207 (using #ifdef), and the resulting code with the new feature
6208 disabled must not need more memory than the old code without your
6211 * Remember that there is a size limit of 100 kB per message on the
6212 u-boot mailing list. Bigger patches will be moderated. If they are
6213 reasonable and not too big, they will be acknowledged. But patches
6214 bigger than the size limit should be avoided.