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 candiate 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 /blackfin Files generic to Analog Devices Blackfin architecture
141 /m68k Files generic to m68k architecture
142 /microblaze Files generic to microblaze architecture
143 /mips Files generic to MIPS architecture
144 /nds32 Files generic to NDS32 architecture
145 /nios2 Files generic to Altera NIOS2 architecture
146 /openrisc Files generic to OpenRISC architecture
147 /powerpc Files generic to PowerPC architecture
148 /sandbox Files generic to HW-independent "sandbox"
149 /sh Files generic to SH architecture
150 /sparc Files generic to SPARC architecture
151 /x86 Files generic to x86 architecture
152 /api Machine/arch independent API for external apps
153 /board Board dependent files
154 /cmd U-Boot commands functions
155 /common Misc architecture independent functions
156 /configs Board default configuration files
157 /disk Code for disk drive partition handling
158 /doc Documentation (don't expect too much)
159 /drivers Commonly used device drivers
160 /dts Contains Makefile for building internal U-Boot fdt.
161 /examples Example code for standalone applications, etc.
162 /fs Filesystem code (cramfs, ext2, jffs2, etc.)
163 /include Header Files
164 /lib Library routines generic to all architectures
165 /Licenses Various license files
167 /post Power On Self Test
168 /scripts Various build scripts and Makefiles
169 /test Various unit test files
170 /tools Tools to build S-Record or U-Boot images, etc.
172 Software Configuration:
173 =======================
175 Configuration is usually done using C preprocessor defines; the
176 rationale behind that is to avoid dead code whenever possible.
178 There are two classes of configuration variables:
180 * Configuration _OPTIONS_:
181 These are selectable by the user and have names beginning with
184 * Configuration _SETTINGS_:
185 These depend on the hardware etc. and should not be meddled with if
186 you don't know what you're doing; they have names beginning with
189 Previously, all configuration was done by hand, which involved creating
190 symbolic links and editing configuration files manually. More recently,
191 U-Boot has added the Kbuild infrastructure used by the Linux kernel,
192 allowing you to use the "make menuconfig" command to configure your
196 Selection of Processor Architecture and Board Type:
197 ---------------------------------------------------
199 For all supported boards there are ready-to-use default
200 configurations available; just type "make <board_name>_defconfig".
202 Example: For a TQM823L module type:
205 make TQM823L_defconfig
207 Note: If you're looking for the default configuration file for a board
208 you're sure used to be there but is now missing, check the file
209 doc/README.scrapyard for a list of no longer supported boards.
214 U-Boot can be built natively to run on a Linux host using the 'sandbox'
215 board. This allows feature development which is not board- or architecture-
216 specific to be undertaken on a native platform. The sandbox is also used to
217 run some of U-Boot's tests.
219 See board/sandbox/README.sandbox for more details.
222 Board Initialisation Flow:
223 --------------------------
225 This is the intended start-up flow for boards. This should apply for both
226 SPL and U-Boot proper (i.e. they both follow the same rules).
228 Note: "SPL" stands for "Secondary Program Loader," which is explained in
229 more detail later in this file.
231 At present, SPL mostly uses a separate code path, but the function names
232 and roles of each function are the same. Some boards or architectures
233 may not conform to this. At least most ARM boards which use
234 CONFIG_SPL_FRAMEWORK conform to this.
236 Execution typically starts with an architecture-specific (and possibly
237 CPU-specific) start.S file, such as:
239 - arch/arm/cpu/armv7/start.S
240 - arch/powerpc/cpu/mpc83xx/start.S
241 - arch/mips/cpu/start.S
243 and so on. From there, three functions are called; the purpose and
244 limitations of each of these functions are described below.
247 - purpose: essential init to permit execution to reach board_init_f()
248 - no global_data or BSS
249 - there is no stack (ARMv7 may have one but it will soon be removed)
250 - must not set up SDRAM or use console
251 - must only do the bare minimum to allow execution to continue to
253 - this is almost never needed
254 - return normally from this function
257 - purpose: set up the machine ready for running board_init_r():
258 i.e. SDRAM and serial UART
259 - global_data is available
261 - BSS is not available, so you cannot use global/static variables,
262 only stack variables and global_data
264 Non-SPL-specific notes:
265 - dram_init() is called to set up DRAM. If already done in SPL this
269 - you can override the entire board_init_f() function with your own
271 - preloader_console_init() can be called here in extremis
272 - should set up SDRAM, and anything needed to make the UART work
273 - these is no need to clear BSS, it will be done by crt0.S
274 - must return normally from this function (don't call board_init_r()
277 Here the BSS is cleared. For SPL, if CONFIG_SPL_STACK_R is defined, then at
278 this point the stack and global_data are relocated to below
279 CONFIG_SPL_STACK_R_ADDR. For non-SPL, U-Boot is relocated to run at the top of
283 - purpose: main execution, common code
284 - global_data is available
286 - BSS is available, all static/global variables can be used
287 - execution eventually continues to main_loop()
289 Non-SPL-specific notes:
290 - U-Boot is relocated to the top of memory and is now running from
294 - stack is optionally in SDRAM, if CONFIG_SPL_STACK_R is defined and
295 CONFIG_SPL_STACK_R_ADDR points into SDRAM
296 - preloader_console_init() can be called here - typically this is
297 done by defining CONFIG_SPL_BOARD_INIT and then supplying a
298 spl_board_init() function containing this call
299 - loads U-Boot or (in falcon mode) Linux
303 Configuration Options:
304 ----------------------
306 Configuration depends on the combination of board and CPU type; all
307 such information is kept in a configuration file
308 "include/configs/<board_name>.h".
310 Example: For a TQM823L module, all configuration settings are in
311 "include/configs/TQM823L.h".
314 Many of the options are named exactly as the corresponding Linux
315 kernel configuration options. The intention is to make it easier to
316 build a config tool - later.
319 The following options need to be configured:
321 - CPU Type: Define exactly one, e.g. CONFIG_MPC85XX.
323 - Board Type: Define exactly one, e.g. CONFIG_MPC8540ADS.
325 - CPU Daughterboard Type: (if CONFIG_ATSTK1000 is defined)
326 Define exactly one, e.g. CONFIG_ATSTK1002
328 - CPU Module Type: (if CONFIG_COGENT is defined)
329 Define exactly one of
331 --- FIXME --- not tested yet:
332 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P,
333 CONFIG_CMA287_23, CONFIG_CMA287_50
335 - Motherboard Type: (if CONFIG_COGENT is defined)
336 Define exactly one of
337 CONFIG_CMA101, CONFIG_CMA102
339 - Motherboard I/O Modules: (if CONFIG_COGENT is defined)
340 Define one or more of
343 - Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined)
344 Define one or more of
345 CONFIG_LCD_HEARTBEAT - update a character position on
346 the LCD display every second with
349 - Marvell Family Member
350 CONFIG_SYS_MVFS - define it if you want to enable
351 multiple fs option at one time
352 for marvell soc family
354 - 8xx CPU Options: (if using an MPC8xx CPU)
355 CONFIG_8xx_GCLK_FREQ - deprecated: CPU clock if
356 get_gclk_freq() cannot work
357 e.g. if there is no 32KHz
358 reference PIT/RTC clock
359 CONFIG_8xx_OSCLK - PLL input clock (either EXTCLK
362 - 859/866/885 CPU options: (if using a MPC859 or MPC866 or MPC885 CPU):
363 CONFIG_SYS_8xx_CPUCLK_MIN
364 CONFIG_SYS_8xx_CPUCLK_MAX
365 CONFIG_8xx_CPUCLK_DEFAULT
366 See doc/README.MPC866
368 CONFIG_SYS_MEASURE_CPUCLK
370 Define this to measure the actual CPU clock instead
371 of relying on the correctness of the configured
372 values. Mostly useful for board bringup to make sure
373 the PLL is locked at the intended frequency. Note
374 that this requires a (stable) reference clock (32 kHz
375 RTC clock or CONFIG_SYS_8XX_XIN)
377 CONFIG_SYS_DELAYED_ICACHE
379 Define this option if you want to enable the
380 ICache only when Code runs from RAM.
385 Specifies that the core is a 64-bit PowerPC implementation (implements
386 the "64" category of the Power ISA). This is necessary for ePAPR
387 compliance, among other possible reasons.
389 CONFIG_SYS_FSL_TBCLK_DIV
391 Defines the core time base clock divider ratio compared to the
392 system clock. On most PQ3 devices this is 8, on newer QorIQ
393 devices it can be 16 or 32. The ratio varies from SoC to Soc.
395 CONFIG_SYS_FSL_PCIE_COMPAT
397 Defines the string to utilize when trying to match PCIe device
398 tree nodes for the given platform.
400 CONFIG_SYS_PPC_E500_DEBUG_TLB
402 Enables a temporary TLB entry to be used during boot to work
403 around limitations in e500v1 and e500v2 external debugger
404 support. This reduces the portions of the boot code where
405 breakpoints and single stepping do not work. The value of this
406 symbol should be set to the TLB1 entry to be used for this
409 CONFIG_SYS_FSL_ERRATUM_A004510
411 Enables a workaround for erratum A004510. If set,
412 then CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV and
413 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY must be set.
415 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV
416 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV2 (optional)
418 Defines one or two SoC revisions (low 8 bits of SVR)
419 for which the A004510 workaround should be applied.
421 The rest of SVR is either not relevant to the decision
422 of whether the erratum is present (e.g. p2040 versus
423 p2041) or is implied by the build target, which controls
424 whether CONFIG_SYS_FSL_ERRATUM_A004510 is set.
426 See Freescale App Note 4493 for more information about
429 CONFIG_A003399_NOR_WORKAROUND
430 Enables a workaround for IFC erratum A003399. It is only
431 required during NOR boot.
433 CONFIG_A008044_WORKAROUND
434 Enables a workaround for T1040/T1042 erratum A008044. It is only
435 required during NAND boot and valid for Rev 1.0 SoC revision
437 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY
439 This is the value to write into CCSR offset 0x18600
440 according to the A004510 workaround.
442 CONFIG_SYS_FSL_DSP_DDR_ADDR
443 This value denotes start offset of DDR memory which is
444 connected exclusively to the DSP cores.
446 CONFIG_SYS_FSL_DSP_M2_RAM_ADDR
447 This value denotes start offset of M2 memory
448 which is directly connected to the DSP core.
450 CONFIG_SYS_FSL_DSP_M3_RAM_ADDR
451 This value denotes start offset of M3 memory which is directly
452 connected to the DSP core.
454 CONFIG_SYS_FSL_DSP_CCSRBAR_DEFAULT
455 This value denotes start offset of DSP CCSR space.
457 CONFIG_SYS_FSL_SINGLE_SOURCE_CLK
458 Single Source Clock is clocking mode present in some of FSL SoC's.
459 In this mode, a single differential clock is used to supply
460 clocks to the sysclock, ddrclock and usbclock.
462 CONFIG_SYS_CPC_REINIT_F
463 This CONFIG is defined when the CPC is configured as SRAM at the
464 time of U-Boot entry and is required to be re-initialized.
467 Indicates this SoC supports deep sleep feature. If deep sleep is
468 supported, core will start to execute uboot when wakes up.
470 - Generic CPU options:
471 CONFIG_SYS_GENERIC_GLOBAL_DATA
472 Defines global data is initialized in generic board board_init_f().
473 If this macro is defined, global data is created and cleared in
474 generic board board_init_f(). Without this macro, architecture/board
475 should initialize global data before calling board_init_f().
477 CONFIG_SYS_BIG_ENDIAN, CONFIG_SYS_LITTLE_ENDIAN
479 Defines the endianess of the CPU. Implementation of those
480 values is arch specific.
483 Freescale DDR driver in use. This type of DDR controller is
484 found in mpc83xx, mpc85xx, mpc86xx as well as some ARM core
487 CONFIG_SYS_FSL_DDR_ADDR
488 Freescale DDR memory-mapped register base.
490 CONFIG_SYS_FSL_DDR_EMU
491 Specify emulator support for DDR. Some DDR features such as
492 deskew training are not available.
494 CONFIG_SYS_FSL_DDRC_GEN1
495 Freescale DDR1 controller.
497 CONFIG_SYS_FSL_DDRC_GEN2
498 Freescale DDR2 controller.
500 CONFIG_SYS_FSL_DDRC_GEN3
501 Freescale DDR3 controller.
503 CONFIG_SYS_FSL_DDRC_GEN4
504 Freescale DDR4 controller.
506 CONFIG_SYS_FSL_DDRC_ARM_GEN3
507 Freescale DDR3 controller for ARM-based SoCs.
510 Board config to use DDR1. It can be enabled for SoCs with
511 Freescale DDR1 or DDR2 controllers, depending on the board
515 Board config to use DDR2. It can be enabled for SoCs with
516 Freescale DDR2 or DDR3 controllers, depending on the board
520 Board config to use DDR3. It can be enabled for SoCs with
521 Freescale DDR3 or DDR3L controllers.
524 Board config to use DDR3L. It can be enabled for SoCs with
528 Board config to use DDR4. It can be enabled for SoCs with
531 CONFIG_SYS_FSL_IFC_BE
532 Defines the IFC controller register space as Big Endian
534 CONFIG_SYS_FSL_IFC_LE
535 Defines the IFC controller register space as Little Endian
537 CONFIG_SYS_FSL_PBL_PBI
538 It enables addition of RCW (Power on reset configuration) in built image.
539 Please refer doc/README.pblimage for more details
541 CONFIG_SYS_FSL_PBL_RCW
542 It adds PBI(pre-boot instructions) commands in u-boot build image.
543 PBI commands can be used to configure SoC before it starts the execution.
544 Please refer doc/README.pblimage for more details
547 It adds a target to create boot binary having SPL binary in PBI format
548 concatenated with u-boot binary.
550 CONFIG_SYS_FSL_DDR_BE
551 Defines the DDR controller register space as Big Endian
553 CONFIG_SYS_FSL_DDR_LE
554 Defines the DDR controller register space as Little Endian
556 CONFIG_SYS_FSL_DDR_SDRAM_BASE_PHY
557 Physical address from the view of DDR controllers. It is the
558 same as CONFIG_SYS_DDR_SDRAM_BASE for all Power SoCs. But
559 it could be different for ARM SoCs.
561 CONFIG_SYS_FSL_DDR_INTLV_256B
562 DDR controller interleaving on 256-byte. This is a special
563 interleaving mode, handled by Dickens for Freescale layerscape
566 CONFIG_SYS_FSL_DDR_MAIN_NUM_CTRLS
567 Number of controllers used as main memory.
569 CONFIG_SYS_FSL_OTHER_DDR_NUM_CTRLS
570 Number of controllers used for other than main memory.
572 CONFIG_SYS_FSL_HAS_DP_DDR
573 Defines the SoC has DP-DDR used for DPAA.
575 CONFIG_SYS_FSL_SEC_BE
576 Defines the SEC controller register space as Big Endian
578 CONFIG_SYS_FSL_SEC_LE
579 Defines the SEC controller register space as Little Endian
581 - Intel Monahans options:
582 CONFIG_SYS_MONAHANS_RUN_MODE_OSC_RATIO
584 Defines the Monahans run mode to oscillator
585 ratio. Valid values are 8, 16, 24, 31. The core
586 frequency is this value multiplied by 13 MHz.
588 CONFIG_SYS_MONAHANS_TURBO_RUN_MODE_RATIO
590 Defines the Monahans turbo mode to oscillator
591 ratio. Valid values are 1 (default if undefined) and
592 2. The core frequency as calculated above is multiplied
596 CONFIG_SYS_INIT_SP_OFFSET
598 Offset relative to CONFIG_SYS_SDRAM_BASE for initial stack
599 pointer. This is needed for the temporary stack before
602 CONFIG_SYS_MIPS_CACHE_MODE
604 Cache operation mode for the MIPS CPU.
605 See also arch/mips/include/asm/mipsregs.h.
607 CONF_CM_CACHABLE_NO_WA
610 CONF_CM_CACHABLE_NONCOHERENT
614 CONF_CM_CACHABLE_ACCELERATED
616 CONFIG_SYS_XWAY_EBU_BOOTCFG
618 Special option for Lantiq XWAY SoCs for booting from NOR flash.
619 See also arch/mips/cpu/mips32/start.S.
621 CONFIG_XWAY_SWAP_BYTES
623 Enable compilation of tools/xway-swap-bytes needed for Lantiq
624 XWAY SoCs for booting from NOR flash. The U-Boot image needs to
625 be swapped if a flash programmer is used.
628 CONFIG_SYS_EXCEPTION_VECTORS_HIGH
630 Select high exception vectors of the ARM core, e.g., do not
631 clear the V bit of the c1 register of CP15.
633 CONFIG_SYS_THUMB_BUILD
635 Use this flag to build U-Boot using the Thumb instruction
636 set for ARM architectures. Thumb instruction set provides
637 better code density. For ARM architectures that support
638 Thumb2 this flag will result in Thumb2 code generated by
641 CONFIG_ARM_ERRATA_716044
642 CONFIG_ARM_ERRATA_742230
643 CONFIG_ARM_ERRATA_743622
644 CONFIG_ARM_ERRATA_751472
645 CONFIG_ARM_ERRATA_761320
646 CONFIG_ARM_ERRATA_773022
647 CONFIG_ARM_ERRATA_774769
648 CONFIG_ARM_ERRATA_794072
650 If set, the workarounds for these ARM errata are applied early
651 during U-Boot startup. Note that these options force the
652 workarounds to be applied; no CPU-type/version detection
653 exists, unlike the similar options in the Linux kernel. Do not
654 set these options unless they apply!
657 Generic timer clock source frequency.
659 COUNTER_FREQUENCY_REAL
660 Generic timer clock source frequency if the real clock is
661 different from COUNTER_FREQUENCY, and can only be determined
664 NOTE: The following can be machine specific errata. These
665 do have ability to provide rudimentary version and machine
666 specific checks, but expect no product checks.
667 CONFIG_ARM_ERRATA_430973
668 CONFIG_ARM_ERRATA_454179
669 CONFIG_ARM_ERRATA_621766
670 CONFIG_ARM_ERRATA_798870
671 CONFIG_ARM_ERRATA_801819
674 CONFIG_TEGRA_SUPPORT_NON_SECURE
676 Support executing U-Boot in non-secure (NS) mode. Certain
677 impossible actions will be skipped if the CPU is in NS mode,
678 such as ARM architectural timer initialization.
680 - Linux Kernel Interface:
683 U-Boot stores all clock information in Hz
684 internally. For binary compatibility with older Linux
685 kernels (which expect the clocks passed in the
686 bd_info data to be in MHz) the environment variable
687 "clocks_in_mhz" can be defined so that U-Boot
688 converts clock data to MHZ before passing it to the
690 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
691 "clocks_in_mhz=1" is automatically included in the
694 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
696 When transferring memsize parameter to Linux, some versions
697 expect it to be in bytes, others in MB.
698 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
702 New kernel versions are expecting firmware settings to be
703 passed using flattened device trees (based on open firmware
707 * New libfdt-based support
708 * Adds the "fdt" command
709 * The bootm command automatically updates the fdt
711 OF_CPU - The proper name of the cpus node (only required for
712 MPC512X and MPC5xxx based boards).
713 OF_SOC - The proper name of the soc node (only required for
714 MPC512X and MPC5xxx based boards).
715 OF_TBCLK - The timebase frequency.
716 OF_STDOUT_PATH - The path to the console device
718 boards with QUICC Engines require OF_QE to set UCC MAC
721 CONFIG_OF_BOARD_SETUP
723 Board code has addition modification that it wants to make
724 to the flat device tree before handing it off to the kernel
726 CONFIG_OF_SYSTEM_SETUP
728 Other code has addition modification that it wants to make
729 to the flat device tree before handing it off to the kernel.
730 This causes ft_system_setup() to be called before booting
735 This define fills in the correct boot CPU in the boot
736 param header, the default value is zero if undefined.
740 U-Boot can detect if an IDE device is present or not.
741 If not, and this new config option is activated, U-Boot
742 removes the ATA node from the DTS before booting Linux,
743 so the Linux IDE driver does not probe the device and
744 crash. This is needed for buggy hardware (uc101) where
745 no pull down resistor is connected to the signal IDE5V_DD7.
747 CONFIG_MACH_TYPE [relevant for ARM only][mandatory]
749 This setting is mandatory for all boards that have only one
750 machine type and must be used to specify the machine type
751 number as it appears in the ARM machine registry
752 (see http://www.arm.linux.org.uk/developer/machines/).
753 Only boards that have multiple machine types supported
754 in a single configuration file and the machine type is
755 runtime discoverable, do not have to use this setting.
757 - vxWorks boot parameters:
759 bootvx constructs a valid bootline using the following
760 environments variables: bootdev, bootfile, ipaddr, netmask,
761 serverip, gatewayip, hostname, othbootargs.
762 It loads the vxWorks image pointed bootfile.
764 Note: If a "bootargs" environment is defined, it will overwride
765 the defaults discussed just above.
767 - Cache Configuration:
768 CONFIG_SYS_ICACHE_OFF - Do not enable instruction cache in U-Boot
769 CONFIG_SYS_DCACHE_OFF - Do not enable data cache in U-Boot
770 CONFIG_SYS_L2CACHE_OFF- Do not enable L2 cache in U-Boot
772 - Cache Configuration for ARM:
773 CONFIG_SYS_L2_PL310 - Enable support for ARM PL310 L2 cache
775 CONFIG_SYS_PL310_BASE - Physical base address of PL310
776 controller register space
781 Define this if you want support for Amba PrimeCell PL010 UARTs.
785 Define this if you want support for Amba PrimeCell PL011 UARTs.
789 If you have Amba PrimeCell PL011 UARTs, set this variable to
790 the clock speed of the UARTs.
794 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
795 define this to a list of base addresses for each (supported)
796 port. See e.g. include/configs/versatile.h
798 CONFIG_SERIAL_HW_FLOW_CONTROL
800 Define this variable to enable hw flow control in serial driver.
801 Current user of this option is drivers/serial/nsl16550.c driver
804 Depending on board, define exactly one serial port
805 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
806 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
807 console by defining CONFIG_8xx_CONS_NONE
809 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
810 port routines must be defined elsewhere
811 (i.e. serial_init(), serial_getc(), ...)
814 Enables console device for a color framebuffer. Needs following
815 defines (cf. smiLynxEM, i8042)
816 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
818 VIDEO_HW_RECTFILL graphic chip supports
821 VIDEO_HW_BITBLT graphic chip supports
822 bit-blit (cf. smiLynxEM)
823 VIDEO_VISIBLE_COLS visible pixel columns
825 VIDEO_VISIBLE_ROWS visible pixel rows
826 VIDEO_PIXEL_SIZE bytes per pixel
827 VIDEO_DATA_FORMAT graphic data format
828 (0-5, cf. cfb_console.c)
829 VIDEO_FB_ADRS framebuffer address
830 VIDEO_KBD_INIT_FCT keyboard int fct
831 (i.e. rx51_kp_init())
832 VIDEO_TSTC_FCT test char fct
834 VIDEO_GETC_FCT get char fct
836 CONFIG_VIDEO_LOGO display Linux logo in
838 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of
839 linux_logo.h for logo.
840 Requires CONFIG_VIDEO_LOGO
841 CONFIG_CONSOLE_EXTRA_INFO
842 additional board info beside
844 CONFIG_HIDE_LOGO_VERSION
845 do not display bootloader
848 When CONFIG_CFB_CONSOLE_ANSI is defined, console will support
849 a limited number of ANSI escape sequences (cursor control,
850 erase functions and limited graphics rendition control).
852 When CONFIG_CFB_CONSOLE is defined, video console is
853 default i/o. Serial console can be forced with
854 environment 'console=serial'.
856 When CONFIG_SILENT_CONSOLE is defined, all console
857 messages (by U-Boot and Linux!) can be silenced with
858 the "silent" environment variable. See
859 doc/README.silent for more information.
861 CONFIG_SYS_CONSOLE_BG_COL: define the backgroundcolor, default
863 CONFIG_SYS_CONSOLE_FG_COL: define the foregroundcolor, default
867 CONFIG_BAUDRATE - in bps
868 Select one of the baudrates listed in
869 CONFIG_SYS_BAUDRATE_TABLE, see below.
870 CONFIG_SYS_BRGCLK_PRESCALE, baudrate prescale
872 - Console Rx buffer length
873 With CONFIG_SYS_SMC_RXBUFLEN it is possible to define
874 the maximum receive buffer length for the SMC.
875 This option is actual only for 82xx and 8xx possible.
876 If using CONFIG_SYS_SMC_RXBUFLEN also CONFIG_SYS_MAXIDLE
877 must be defined, to setup the maximum idle timeout for
880 - Pre-Console Buffer:
881 Prior to the console being initialised (i.e. serial UART
882 initialised etc) all console output is silently discarded.
883 Defining CONFIG_PRE_CONSOLE_BUFFER will cause U-Boot to
884 buffer any console messages prior to the console being
885 initialised to a buffer of size CONFIG_PRE_CON_BUF_SZ
886 bytes located at CONFIG_PRE_CON_BUF_ADDR. The buffer is
887 a circular buffer, so if more than CONFIG_PRE_CON_BUF_SZ
888 bytes are output before the console is initialised, the
889 earlier bytes are discarded.
891 Note that when printing the buffer a copy is made on the
892 stack so CONFIG_PRE_CON_BUF_SZ must fit on the stack.
894 'Sane' compilers will generate smaller code if
895 CONFIG_PRE_CON_BUF_SZ is a power of 2
899 Only needed when CONFIG_BOOTDELAY is enabled;
900 define a command string that is automatically executed
901 when no character is read on the console interface
902 within "Boot Delay" after reset.
905 This can be used to pass arguments to the bootm
906 command. The value of CONFIG_BOOTARGS goes into the
907 environment value "bootargs".
909 CONFIG_RAMBOOT and CONFIG_NFSBOOT
910 The value of these goes into the environment as
911 "ramboot" and "nfsboot" respectively, and can be used
912 as a convenience, when switching between booting from
916 CONFIG_BOOTCOUNT_LIMIT
917 Implements a mechanism for detecting a repeating reboot
919 http://www.denx.de/wiki/view/DULG/UBootBootCountLimit
922 If no softreset save registers are found on the hardware
923 "bootcount" is stored in the environment. To prevent a
924 saveenv on all reboots, the environment variable
925 "upgrade_available" is used. If "upgrade_available" is
926 0, "bootcount" is always 0, if "upgrade_available" is
927 1 "bootcount" is incremented in the environment.
928 So the Userspace Applikation must set the "upgrade_available"
929 and "bootcount" variable to 0, if a boot was successfully.
934 When this option is #defined, the existence of the
935 environment variable "preboot" will be checked
936 immediately before starting the CONFIG_BOOTDELAY
937 countdown and/or running the auto-boot command resp.
938 entering interactive mode.
940 This feature is especially useful when "preboot" is
941 automatically generated or modified. For an example
942 see the LWMON board specific code: here "preboot" is
943 modified when the user holds down a certain
944 combination of keys on the (special) keyboard when
947 - Serial Download Echo Mode:
949 If defined to 1, all characters received during a
950 serial download (using the "loads" command) are
951 echoed back. This might be needed by some terminal
952 emulations (like "cu"), but may as well just take
953 time on others. This setting #define's the initial
954 value of the "loads_echo" environment variable.
956 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
958 Select one of the baudrates listed in
959 CONFIG_SYS_BAUDRATE_TABLE, see below.
962 Monitor commands can be included or excluded
963 from the build by using the #include files
964 <config_cmd_all.h> and #undef'ing unwanted
965 commands, or adding #define's for wanted commands.
967 The default command configuration includes all commands
968 except those marked below with a "*".
970 CONFIG_CMD_AES AES 128 CBC encrypt/decrypt
971 CONFIG_CMD_ASKENV * ask for env variable
972 CONFIG_CMD_BDI bdinfo
973 CONFIG_CMD_BEDBUG * Include BedBug Debugger
974 CONFIG_CMD_BMP * BMP support
975 CONFIG_CMD_BSP * Board specific commands
976 CONFIG_CMD_BOOTD bootd
977 CONFIG_CMD_BOOTI * ARM64 Linux kernel Image support
978 CONFIG_CMD_CACHE * icache, dcache
979 CONFIG_CMD_CLK * clock command support
980 CONFIG_CMD_CONSOLE coninfo
981 CONFIG_CMD_CRC32 * crc32
982 CONFIG_CMD_DATE * support for RTC, date/time...
983 CONFIG_CMD_DHCP * DHCP support
984 CONFIG_CMD_DIAG * Diagnostics
985 CONFIG_CMD_DS4510 * ds4510 I2C gpio commands
986 CONFIG_CMD_DS4510_INFO * ds4510 I2C info command
987 CONFIG_CMD_DS4510_MEM * ds4510 I2C eeprom/sram commansd
988 CONFIG_CMD_DS4510_RST * ds4510 I2C rst command
989 CONFIG_CMD_DTT * Digital Therm and Thermostat
990 CONFIG_CMD_ECHO echo arguments
991 CONFIG_CMD_EDITENV edit env variable
992 CONFIG_CMD_EEPROM * EEPROM read/write support
993 CONFIG_CMD_EEPROM_LAYOUT* EEPROM layout aware commands
994 CONFIG_CMD_ELF * bootelf, bootvx
995 CONFIG_CMD_ENV_CALLBACK * display details about env callbacks
996 CONFIG_CMD_ENV_FLAGS * display details about env flags
997 CONFIG_CMD_ENV_EXISTS * check existence of env variable
998 CONFIG_CMD_EXPORTENV * export the environment
999 CONFIG_CMD_EXT2 * ext2 command support
1000 CONFIG_CMD_EXT4 * ext4 command support
1001 CONFIG_CMD_FS_GENERIC * filesystem commands (e.g. load, ls)
1002 that work for multiple fs types
1003 CONFIG_CMD_FS_UUID * Look up a filesystem UUID
1004 CONFIG_CMD_SAVEENV saveenv
1005 CONFIG_CMD_FDC * Floppy Disk Support
1006 CONFIG_CMD_FAT * FAT command support
1007 CONFIG_CMD_FLASH flinfo, erase, protect
1008 CONFIG_CMD_FPGA FPGA device initialization support
1009 CONFIG_CMD_FUSE * Device fuse support
1010 CONFIG_CMD_GETTIME * Get time since boot
1011 CONFIG_CMD_GO * the 'go' command (exec code)
1012 CONFIG_CMD_GREPENV * search environment
1013 CONFIG_CMD_HASH * calculate hash / digest
1014 CONFIG_CMD_I2C * I2C serial bus support
1015 CONFIG_CMD_IDE * IDE harddisk support
1016 CONFIG_CMD_IMI iminfo
1017 CONFIG_CMD_IMLS List all images found in NOR flash
1018 CONFIG_CMD_IMLS_NAND * List all images found in NAND flash
1019 CONFIG_CMD_IMMAP * IMMR dump support
1020 CONFIG_CMD_IOTRACE * I/O tracing for debugging
1021 CONFIG_CMD_IMPORTENV * import an environment
1022 CONFIG_CMD_INI * import data from an ini file into the env
1023 CONFIG_CMD_IRQ * irqinfo
1024 CONFIG_CMD_ITEST Integer/string test of 2 values
1025 CONFIG_CMD_JFFS2 * JFFS2 Support
1026 CONFIG_CMD_KGDB * kgdb
1027 CONFIG_CMD_LDRINFO * ldrinfo (display Blackfin loader)
1028 CONFIG_CMD_LINK_LOCAL * link-local IP address auto-configuration
1030 CONFIG_CMD_LOADB loadb
1031 CONFIG_CMD_LOADS loads
1032 CONFIG_CMD_MD5SUM * print md5 message digest
1033 (requires CONFIG_CMD_MEMORY and CONFIG_MD5)
1034 CONFIG_CMD_MEMINFO * Display detailed memory information
1035 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
1037 CONFIG_CMD_MEMTEST * mtest
1038 CONFIG_CMD_MISC Misc functions like sleep etc
1039 CONFIG_CMD_MMC * MMC memory mapped support
1040 CONFIG_CMD_MII * MII utility commands
1041 CONFIG_CMD_MTDPARTS * MTD partition support
1042 CONFIG_CMD_NAND * NAND support
1043 CONFIG_CMD_NET bootp, tftpboot, rarpboot
1044 CONFIG_CMD_NFS NFS support
1045 CONFIG_CMD_PCA953X * PCA953x I2C gpio commands
1046 CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command
1047 CONFIG_CMD_PCI * pciinfo
1048 CONFIG_CMD_PCMCIA * PCMCIA support
1049 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
1051 CONFIG_CMD_PORTIO * Port I/O
1052 CONFIG_CMD_READ * Read raw data from partition
1053 CONFIG_CMD_REGINFO * Register dump
1054 CONFIG_CMD_RUN run command in env variable
1055 CONFIG_CMD_SANDBOX * sb command to access sandbox features
1056 CONFIG_CMD_SAVES * save S record dump
1057 CONFIG_SCSI * SCSI Support
1058 CONFIG_CMD_SDRAM * print SDRAM configuration information
1059 (requires CONFIG_CMD_I2C)
1060 CONFIG_CMD_SETGETDCR Support for DCR Register access
1062 CONFIG_CMD_SF * Read/write/erase SPI NOR flash
1063 CONFIG_CMD_SHA1SUM * print sha1 memory digest
1064 (requires CONFIG_CMD_MEMORY)
1065 CONFIG_CMD_SOFTSWITCH * Soft switch setting command for BF60x
1066 CONFIG_CMD_SOURCE "source" command Support
1067 CONFIG_CMD_SPI * SPI serial bus support
1068 CONFIG_CMD_TFTPSRV * TFTP transfer in server mode
1069 CONFIG_CMD_TFTPPUT * TFTP put command (upload)
1070 CONFIG_CMD_TIME * run command and report execution time (ARM specific)
1071 CONFIG_CMD_TIMER * access to the system tick timer
1072 CONFIG_CMD_USB * USB support
1073 CONFIG_CMD_CDP * Cisco Discover Protocol support
1074 CONFIG_CMD_MFSL * Microblaze FSL support
1075 CONFIG_CMD_XIMG Load part of Multi Image
1076 CONFIG_CMD_UUID * Generate random UUID or GUID string
1078 EXAMPLE: If you want all functions except of network
1079 support you can write:
1081 #include "config_cmd_all.h"
1082 #undef CONFIG_CMD_NET
1085 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
1087 Note: Don't enable the "icache" and "dcache" commands
1088 (configuration option CONFIG_CMD_CACHE) unless you know
1089 what you (and your U-Boot users) are doing. Data
1090 cache cannot be enabled on systems like the 8xx or
1091 8260 (where accesses to the IMMR region must be
1092 uncached), and it cannot be disabled on all other
1093 systems where we (mis-) use the data cache to hold an
1094 initial stack and some data.
1097 XXX - this list needs to get updated!
1099 - Removal of commands
1100 If no commands are needed to boot, you can disable
1101 CONFIG_CMDLINE to remove them. In this case, the command line
1102 will not be available, and when U-Boot wants to execute the
1103 boot command (on start-up) it will call board_run_command()
1104 instead. This can reduce image size significantly for very
1105 simple boot procedures.
1107 - Regular expression support:
1109 If this variable is defined, U-Boot is linked against
1110 the SLRE (Super Light Regular Expression) library,
1111 which adds regex support to some commands, as for
1112 example "env grep" and "setexpr".
1116 If this variable is defined, U-Boot will use a device tree
1117 to configure its devices, instead of relying on statically
1118 compiled #defines in the board file. This option is
1119 experimental and only available on a few boards. The device
1120 tree is available in the global data as gd->fdt_blob.
1122 U-Boot needs to get its device tree from somewhere. This can
1123 be done using one of the two options below:
1126 If this variable is defined, U-Boot will embed a device tree
1127 binary in its image. This device tree file should be in the
1128 board directory and called <soc>-<board>.dts. The binary file
1129 is then picked up in board_init_f() and made available through
1130 the global data structure as gd->blob.
1133 If this variable is defined, U-Boot will build a device tree
1134 binary. It will be called u-boot.dtb. Architecture-specific
1135 code will locate it at run-time. Generally this works by:
1137 cat u-boot.bin u-boot.dtb >image.bin
1139 and in fact, U-Boot does this for you, creating a file called
1140 u-boot-dtb.bin which is useful in the common case. You can
1141 still use the individual files if you need something more
1146 If this variable is defined, it enables watchdog
1147 support for the SoC. There must be support in the SoC
1148 specific code for a watchdog. For the 8xx and 8260
1149 CPUs, the SIU Watchdog feature is enabled in the SYPCR
1150 register. When supported for a specific SoC is
1151 available, then no further board specific code should
1152 be needed to use it.
1155 When using a watchdog circuitry external to the used
1156 SoC, then define this variable and provide board
1157 specific code for the "hw_watchdog_reset" function.
1159 CONFIG_AT91_HW_WDT_TIMEOUT
1160 specify the timeout in seconds. default 2 seconds.
1163 CONFIG_VERSION_VARIABLE
1164 If this variable is defined, an environment variable
1165 named "ver" is created by U-Boot showing the U-Boot
1166 version as printed by the "version" command.
1167 Any change to this variable will be reverted at the
1172 When CONFIG_CMD_DATE is selected, the type of the RTC
1173 has to be selected, too. Define exactly one of the
1176 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
1177 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
1178 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC
1179 CONFIG_RTC_MC146818 - use MC146818 RTC
1180 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
1181 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
1182 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
1183 CONFIG_RTC_DS1339 - use Maxim, Inc. DS1339 RTC
1184 CONFIG_RTC_DS164x - use Dallas DS164x RTC
1185 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
1186 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
1187 CONFIG_SYS_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
1188 CONFIG_SYS_RV3029_TCR - enable trickle charger on
1191 Note that if the RTC uses I2C, then the I2C interface
1192 must also be configured. See I2C Support, below.
1195 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
1197 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
1198 chip-ngpio pairs that tell the PCA953X driver the number of
1199 pins supported by a particular chip.
1201 Note that if the GPIO device uses I2C, then the I2C interface
1202 must also be configured. See I2C Support, below.
1205 When CONFIG_IO_TRACE is selected, U-Boot intercepts all I/O
1206 accesses and can checksum them or write a list of them out
1207 to memory. See the 'iotrace' command for details. This is
1208 useful for testing device drivers since it can confirm that
1209 the driver behaves the same way before and after a code
1210 change. Currently this is supported on sandbox and arm. To
1211 add support for your architecture, add '#include <iotrace.h>'
1212 to the bottom of arch/<arch>/include/asm/io.h and test.
1214 Example output from the 'iotrace stats' command is below.
1215 Note that if the trace buffer is exhausted, the checksum will
1216 still continue to operate.
1219 Start: 10000000 (buffer start address)
1220 Size: 00010000 (buffer size)
1221 Offset: 00000120 (current buffer offset)
1222 Output: 10000120 (start + offset)
1223 Count: 00000018 (number of trace records)
1224 CRC32: 9526fb66 (CRC32 of all trace records)
1226 - Timestamp Support:
1228 When CONFIG_TIMESTAMP is selected, the timestamp
1229 (date and time) of an image is printed by image
1230 commands like bootm or iminfo. This option is
1231 automatically enabled when you select CONFIG_CMD_DATE .
1233 - Partition Labels (disklabels) Supported:
1234 Zero or more of the following:
1235 CONFIG_MAC_PARTITION Apple's MacOS partition table.
1236 CONFIG_DOS_PARTITION MS Dos partition table, traditional on the
1237 Intel architecture, USB sticks, etc.
1238 CONFIG_ISO_PARTITION ISO partition table, used on CDROM etc.
1239 CONFIG_EFI_PARTITION GPT partition table, common when EFI is the
1240 bootloader. Note 2TB partition limit; see
1242 CONFIG_MTD_PARTITIONS Memory Technology Device partition table.
1244 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
1245 CONFIG_SCSI) you must configure support for at
1246 least one non-MTD partition type as well.
1249 CONFIG_IDE_RESET_ROUTINE - this is defined in several
1250 board configurations files but used nowhere!
1252 CONFIG_IDE_RESET - is this is defined, IDE Reset will
1253 be performed by calling the function
1254 ide_set_reset(int reset)
1255 which has to be defined in a board specific file
1260 Set this to enable ATAPI support.
1265 Set this to enable support for disks larger than 137GB
1266 Also look at CONFIG_SYS_64BIT_LBA.
1267 Whithout these , LBA48 support uses 32bit variables and will 'only'
1268 support disks up to 2.1TB.
1270 CONFIG_SYS_64BIT_LBA:
1271 When enabled, makes the IDE subsystem use 64bit sector addresses.
1275 At the moment only there is only support for the
1276 SYM53C8XX SCSI controller; define
1277 CONFIG_SCSI_SYM53C8XX to enable it.
1279 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
1280 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
1281 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
1282 maximum numbers of LUNs, SCSI ID's and target
1284 CONFIG_SYS_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
1286 The environment variable 'scsidevs' is set to the number of
1287 SCSI devices found during the last scan.
1289 - NETWORK Support (PCI):
1291 Support for Intel 8254x/8257x gigabit chips.
1294 Utility code for direct access to the SPI bus on Intel 8257x.
1295 This does not do anything useful unless you set at least one
1296 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
1298 CONFIG_E1000_SPI_GENERIC
1299 Allow generic access to the SPI bus on the Intel 8257x, for
1300 example with the "sspi" command.
1303 Management command for E1000 devices. When used on devices
1304 with SPI support you can reprogram the EEPROM from U-Boot.
1307 Support for Intel 82557/82559/82559ER chips.
1308 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
1309 write routine for first time initialisation.
1312 Support for Digital 2114x chips.
1313 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
1314 modem chip initialisation (KS8761/QS6611).
1317 Support for National dp83815 chips.
1320 Support for National dp8382[01] gigabit chips.
1322 - NETWORK Support (other):
1324 CONFIG_DRIVER_AT91EMAC
1325 Support for AT91RM9200 EMAC.
1328 Define this to use reduced MII inteface
1330 CONFIG_DRIVER_AT91EMAC_QUIET
1331 If this defined, the driver is quiet.
1332 The driver doen't show link status messages.
1334 CONFIG_CALXEDA_XGMAC
1335 Support for the Calxeda XGMAC device
1338 Support for SMSC's LAN91C96 chips.
1340 CONFIG_LAN91C96_BASE
1341 Define this to hold the physical address
1342 of the LAN91C96's I/O space
1344 CONFIG_LAN91C96_USE_32_BIT
1345 Define this to enable 32 bit addressing
1348 Support for SMSC's LAN91C111 chip
1350 CONFIG_SMC91111_BASE
1351 Define this to hold the physical address
1352 of the device (I/O space)
1354 CONFIG_SMC_USE_32_BIT
1355 Define this if data bus is 32 bits
1357 CONFIG_SMC_USE_IOFUNCS
1358 Define this to use i/o functions instead of macros
1359 (some hardware wont work with macros)
1361 CONFIG_DRIVER_TI_EMAC
1362 Support for davinci emac
1364 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
1365 Define this if you have more then 3 PHYs.
1368 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
1370 CONFIG_FTGMAC100_EGIGA
1371 Define this to use GE link update with gigabit PHY.
1372 Define this if FTGMAC100 is connected to gigabit PHY.
1373 If your system has 10/100 PHY only, it might not occur
1374 wrong behavior. Because PHY usually return timeout or
1375 useless data when polling gigabit status and gigabit
1376 control registers. This behavior won't affect the
1377 correctnessof 10/100 link speed update.
1380 Support for SMSC's LAN911x and LAN921x chips
1383 Define this to hold the physical address
1384 of the device (I/O space)
1386 CONFIG_SMC911X_32_BIT
1387 Define this if data bus is 32 bits
1389 CONFIG_SMC911X_16_BIT
1390 Define this if data bus is 16 bits. If your processor
1391 automatically converts one 32 bit word to two 16 bit
1392 words you may also try CONFIG_SMC911X_32_BIT.
1395 Support for Renesas on-chip Ethernet controller
1397 CONFIG_SH_ETHER_USE_PORT
1398 Define the number of ports to be used
1400 CONFIG_SH_ETHER_PHY_ADDR
1401 Define the ETH PHY's address
1403 CONFIG_SH_ETHER_CACHE_WRITEBACK
1404 If this option is set, the driver enables cache flush.
1408 Support for PWM modul on the imx6.
1412 Support TPM devices.
1414 CONFIG_TPM_TIS_INFINEON
1415 Support for Infineon i2c bus TPM devices. Only one device
1416 per system is supported at this time.
1418 CONFIG_TPM_TIS_I2C_BURST_LIMITATION
1419 Define the burst count bytes upper limit
1422 Support for STMicroelectronics TPM devices. Requires DM_TPM support.
1424 CONFIG_TPM_ST33ZP24_I2C
1425 Support for STMicroelectronics ST33ZP24 I2C devices.
1426 Requires TPM_ST33ZP24 and I2C.
1428 CONFIG_TPM_ST33ZP24_SPI
1429 Support for STMicroelectronics ST33ZP24 SPI devices.
1430 Requires TPM_ST33ZP24 and SPI.
1432 CONFIG_TPM_ATMEL_TWI
1433 Support for Atmel TWI TPM device. Requires I2C support.
1436 Support for generic parallel port TPM devices. Only one device
1437 per system is supported at this time.
1439 CONFIG_TPM_TIS_BASE_ADDRESS
1440 Base address where the generic TPM device is mapped
1441 to. Contemporary x86 systems usually map it at
1445 Add tpm monitor functions.
1446 Requires CONFIG_TPM. If CONFIG_TPM_AUTH_SESSIONS is set, also
1447 provides monitor access to authorized functions.
1450 Define this to enable the TPM support library which provides
1451 functional interfaces to some TPM commands.
1452 Requires support for a TPM device.
1454 CONFIG_TPM_AUTH_SESSIONS
1455 Define this to enable authorized functions in the TPM library.
1456 Requires CONFIG_TPM and CONFIG_SHA1.
1459 At the moment only the UHCI host controller is
1460 supported (PIP405, MIP405, MPC5200); define
1461 CONFIG_USB_UHCI to enable it.
1462 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
1463 and define CONFIG_USB_STORAGE to enable the USB
1466 Supported are USB Keyboards and USB Floppy drives
1468 MPC5200 USB requires additional defines:
1470 for 528 MHz Clock: 0x0001bbbb
1474 for differential drivers: 0x00001000
1475 for single ended drivers: 0x00005000
1476 for differential drivers on PSC3: 0x00000100
1477 for single ended drivers on PSC3: 0x00004100
1478 CONFIG_SYS_USB_EVENT_POLL
1479 May be defined to allow interrupt polling
1480 instead of using asynchronous interrupts
1482 CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
1483 txfilltuning field in the EHCI controller on reset.
1485 CONFIG_USB_DWC2_REG_ADDR the physical CPU address of the DWC2
1486 HW module registers.
1489 Define the below if you wish to use the USB console.
1490 Once firmware is rebuilt from a serial console issue the
1491 command "setenv stdin usbtty; setenv stdout usbtty" and
1492 attach your USB cable. The Unix command "dmesg" should print
1493 it has found a new device. The environment variable usbtty
1494 can be set to gserial or cdc_acm to enable your device to
1495 appear to a USB host as a Linux gserial device or a
1496 Common Device Class Abstract Control Model serial device.
1497 If you select usbtty = gserial you should be able to enumerate
1499 # modprobe usbserial vendor=0xVendorID product=0xProductID
1500 else if using cdc_acm, simply setting the environment
1501 variable usbtty to be cdc_acm should suffice. The following
1502 might be defined in YourBoardName.h
1505 Define this to build a UDC device
1508 Define this to have a tty type of device available to
1509 talk to the UDC device
1512 Define this to enable the high speed support for usb
1513 device and usbtty. If this feature is enabled, a routine
1514 int is_usbd_high_speed(void)
1515 also needs to be defined by the driver to dynamically poll
1516 whether the enumeration has succeded at high speed or full
1519 CONFIG_SYS_CONSOLE_IS_IN_ENV
1520 Define this if you want stdin, stdout &/or stderr to
1524 CONFIG_SYS_USB_EXTC_CLK 0xBLAH
1525 Derive USB clock from external clock "blah"
1526 - CONFIG_SYS_USB_EXTC_CLK 0x02
1528 CONFIG_SYS_USB_BRG_CLK 0xBLAH
1529 Derive USB clock from brgclk
1530 - CONFIG_SYS_USB_BRG_CLK 0x04
1532 If you have a USB-IF assigned VendorID then you may wish to
1533 define your own vendor specific values either in BoardName.h
1534 or directly in usbd_vendor_info.h. If you don't define
1535 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
1536 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
1537 should pretend to be a Linux device to it's target host.
1539 CONFIG_USBD_MANUFACTURER
1540 Define this string as the name of your company for
1541 - CONFIG_USBD_MANUFACTURER "my company"
1543 CONFIG_USBD_PRODUCT_NAME
1544 Define this string as the name of your product
1545 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
1547 CONFIG_USBD_VENDORID
1548 Define this as your assigned Vendor ID from the USB
1549 Implementors Forum. This *must* be a genuine Vendor ID
1550 to avoid polluting the USB namespace.
1551 - CONFIG_USBD_VENDORID 0xFFFF
1553 CONFIG_USBD_PRODUCTID
1554 Define this as the unique Product ID
1556 - CONFIG_USBD_PRODUCTID 0xFFFF
1558 - ULPI Layer Support:
1559 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
1560 the generic ULPI layer. The generic layer accesses the ULPI PHY
1561 via the platform viewport, so you need both the genric layer and
1562 the viewport enabled. Currently only Chipidea/ARC based
1563 viewport is supported.
1564 To enable the ULPI layer support, define CONFIG_USB_ULPI and
1565 CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
1566 If your ULPI phy needs a different reference clock than the
1567 standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to
1568 the appropriate value in Hz.
1571 The MMC controller on the Intel PXA is supported. To
1572 enable this define CONFIG_MMC. The MMC can be
1573 accessed from the boot prompt by mapping the device
1574 to physical memory similar to flash. Command line is
1575 enabled with CONFIG_CMD_MMC. The MMC driver also works with
1576 the FAT fs. This is enabled with CONFIG_CMD_FAT.
1579 Support for Renesas on-chip MMCIF controller
1581 CONFIG_SH_MMCIF_ADDR
1582 Define the base address of MMCIF registers
1585 Define the clock frequency for MMCIF
1588 Enable the generic MMC driver
1590 CONFIG_SUPPORT_EMMC_BOOT
1591 Enable some additional features of the eMMC boot partitions.
1593 CONFIG_SUPPORT_EMMC_RPMB
1594 Enable the commands for reading, writing and programming the
1595 key for the Replay Protection Memory Block partition in eMMC.
1597 - USB Device Firmware Update (DFU) class support:
1598 CONFIG_USB_FUNCTION_DFU
1599 This enables the USB portion of the DFU USB class
1602 This enables the command "dfu" which is used to have
1603 U-Boot create a DFU class device via USB. This command
1604 requires that the "dfu_alt_info" environment variable be
1605 set and define the alt settings to expose to the host.
1608 This enables support for exposing (e)MMC devices via DFU.
1611 This enables support for exposing NAND devices via DFU.
1614 This enables support for exposing RAM via DFU.
1615 Note: DFU spec refer to non-volatile memory usage, but
1616 allow usages beyond the scope of spec - here RAM usage,
1617 one that would help mostly the developer.
1619 CONFIG_SYS_DFU_DATA_BUF_SIZE
1620 Dfu transfer uses a buffer before writing data to the
1621 raw storage device. Make the size (in bytes) of this buffer
1622 configurable. The size of this buffer is also configurable
1623 through the "dfu_bufsiz" environment variable.
1625 CONFIG_SYS_DFU_MAX_FILE_SIZE
1626 When updating files rather than the raw storage device,
1627 we use a static buffer to copy the file into and then write
1628 the buffer once we've been given the whole file. Define
1629 this to the maximum filesize (in bytes) for the buffer.
1630 Default is 4 MiB if undefined.
1632 DFU_DEFAULT_POLL_TIMEOUT
1633 Poll timeout [ms], is the timeout a device can send to the
1634 host. The host must wait for this timeout before sending
1635 a subsequent DFU_GET_STATUS request to the device.
1637 DFU_MANIFEST_POLL_TIMEOUT
1638 Poll timeout [ms], which the device sends to the host when
1639 entering dfuMANIFEST state. Host waits this timeout, before
1640 sending again an USB request to the device.
1642 - USB Device Android Fastboot support:
1643 CONFIG_USB_FUNCTION_FASTBOOT
1644 This enables the USB part of the fastboot gadget
1647 This enables the command "fastboot" which enables the Android
1648 fastboot mode for the platform's USB device. Fastboot is a USB
1649 protocol for downloading images, flashing and device control
1650 used on Android devices.
1651 See doc/README.android-fastboot for more information.
1653 CONFIG_ANDROID_BOOT_IMAGE
1654 This enables support for booting images which use the Android
1655 image format header.
1657 CONFIG_FASTBOOT_BUF_ADDR
1658 The fastboot protocol requires a large memory buffer for
1659 downloads. Define this to the starting RAM address to use for
1662 CONFIG_FASTBOOT_BUF_SIZE
1663 The fastboot protocol requires a large memory buffer for
1664 downloads. This buffer should be as large as possible for a
1665 platform. Define this to the size available RAM for fastboot.
1667 CONFIG_FASTBOOT_FLASH
1668 The fastboot protocol includes a "flash" command for writing
1669 the downloaded image to a non-volatile storage device. Define
1670 this to enable the "fastboot flash" command.
1672 CONFIG_FASTBOOT_FLASH_MMC_DEV
1673 The fastboot "flash" command requires additional information
1674 regarding the non-volatile storage device. Define this to
1675 the eMMC device that fastboot should use to store the image.
1677 CONFIG_FASTBOOT_GPT_NAME
1678 The fastboot "flash" command supports writing the downloaded
1679 image to the Protective MBR and the Primary GUID Partition
1680 Table. (Additionally, this downloaded image is post-processed
1681 to generate and write the Backup GUID Partition Table.)
1682 This occurs when the specified "partition name" on the
1683 "fastboot flash" command line matches this value.
1684 Default is GPT_ENTRY_NAME (currently "gpt") if undefined.
1686 - Journaling Flash filesystem support:
1687 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
1688 CONFIG_JFFS2_NAND_DEV
1689 Define these for a default partition on a NAND device
1691 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1692 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1693 Define these for a default partition on a NOR device
1695 CONFIG_SYS_JFFS_CUSTOM_PART
1696 Define this to create an own partition. You have to provide a
1697 function struct part_info* jffs2_part_info(int part_num)
1699 If you define only one JFFS2 partition you may also want to
1700 #define CONFIG_SYS_JFFS_SINGLE_PART 1
1701 to disable the command chpart. This is the default when you
1702 have not defined a custom partition
1704 - FAT(File Allocation Table) filesystem write function support:
1707 Define this to enable support for saving memory data as a
1708 file in FAT formatted partition.
1710 This will also enable the command "fatwrite" enabling the
1711 user to write files to FAT.
1713 CBFS (Coreboot Filesystem) support
1716 Define this to enable support for reading from a Coreboot
1717 filesystem. Available commands are cbfsinit, cbfsinfo, cbfsls
1720 - FAT(File Allocation Table) filesystem cluster size:
1721 CONFIG_FS_FAT_MAX_CLUSTSIZE
1723 Define the max cluster size for fat operations else
1724 a default value of 65536 will be defined.
1727 See Kconfig help for available keyboard drivers.
1731 Define this to enable a custom keyboard support.
1732 This simply calls drv_keyboard_init() which must be
1733 defined in your board-specific files. This option is deprecated
1734 and is only used by novena. For new boards, use driver model
1740 Define this to enable video support (for output to
1743 CONFIG_VIDEO_CT69000
1745 Enable Chips & Technologies 69000 Video chip
1747 CONFIG_VIDEO_SMI_LYNXEM
1748 Enable Silicon Motion SMI 712/710/810 Video chip. The
1749 video output is selected via environment 'videoout'
1750 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
1753 For the CT69000 and SMI_LYNXEM drivers, videomode is
1754 selected via environment 'videomode'. Two different ways
1756 - "videomode=num" 'num' is a standard LiLo mode numbers.
1757 Following standard modes are supported (* is default):
1759 Colors 640x480 800x600 1024x768 1152x864 1280x1024
1760 -------------+---------------------------------------------
1761 8 bits | 0x301* 0x303 0x305 0x161 0x307
1762 15 bits | 0x310 0x313 0x316 0x162 0x319
1763 16 bits | 0x311 0x314 0x317 0x163 0x31A
1764 24 bits | 0x312 0x315 0x318 ? 0x31B
1765 -------------+---------------------------------------------
1766 (i.e. setenv videomode 317; saveenv; reset;)
1768 - "videomode=bootargs" all the video parameters are parsed
1769 from the bootargs. (See drivers/video/videomodes.c)
1772 CONFIG_VIDEO_SED13806
1773 Enable Epson SED13806 driver. This driver supports 8bpp
1774 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
1775 or CONFIG_VIDEO_SED13806_16BPP
1778 Enable the Freescale DIU video driver. Reference boards for
1779 SOCs that have a DIU should define this macro to enable DIU
1780 support, and should also define these other macros:
1786 CONFIG_VIDEO_SW_CURSOR
1787 CONFIG_VGA_AS_SINGLE_DEVICE
1789 CONFIG_VIDEO_BMP_LOGO
1791 The DIU driver will look for the 'video-mode' environment
1792 variable, and if defined, enable the DIU as a console during
1793 boot. See the documentation file doc/README.video for a
1794 description of this variable.
1796 - LCD Support: CONFIG_LCD
1798 Define this to enable LCD support (for output to LCD
1799 display); also select one of the supported displays
1800 by defining one of these:
1804 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1806 CONFIG_NEC_NL6448AC33:
1808 NEC NL6448AC33-18. Active, color, single scan.
1810 CONFIG_NEC_NL6448BC20
1812 NEC NL6448BC20-08. 6.5", 640x480.
1813 Active, color, single scan.
1815 CONFIG_NEC_NL6448BC33_54
1817 NEC NL6448BC33-54. 10.4", 640x480.
1818 Active, color, single scan.
1822 Sharp 320x240. Active, color, single scan.
1823 It isn't 16x9, and I am not sure what it is.
1825 CONFIG_SHARP_LQ64D341
1827 Sharp LQ64D341 display, 640x480.
1828 Active, color, single scan.
1832 HLD1045 display, 640x480.
1833 Active, color, single scan.
1837 Optrex CBL50840-2 NF-FW 99 22 M5
1839 Hitachi LMG6912RPFC-00T
1843 320x240. Black & white.
1845 Normally display is black on white background; define
1846 CONFIG_SYS_WHITE_ON_BLACK to get it inverted.
1848 CONFIG_LCD_ALIGNMENT
1850 Normally the LCD is page-aligned (typically 4KB). If this is
1851 defined then the LCD will be aligned to this value instead.
1852 For ARM it is sometimes useful to use MMU_SECTION_SIZE
1853 here, since it is cheaper to change data cache settings on
1854 a per-section basis.
1856 CONFIG_CONSOLE_SCROLL_LINES
1858 When the console need to be scrolled, this is the number of
1859 lines to scroll by. It defaults to 1. Increasing this makes
1860 the console jump but can help speed up operation when scrolling
1865 Sometimes, for example if the display is mounted in portrait
1866 mode or even if it's mounted landscape but rotated by 180degree,
1867 we need to rotate our content of the display relative to the
1868 framebuffer, so that user can read the messages which are
1870 Once CONFIG_LCD_ROTATION is defined, the lcd_console will be
1871 initialized with a given rotation from "vl_rot" out of
1872 "vidinfo_t" which is provided by the board specific code.
1873 The value for vl_rot is coded as following (matching to
1874 fbcon=rotate:<n> linux-kernel commandline):
1875 0 = no rotation respectively 0 degree
1876 1 = 90 degree rotation
1877 2 = 180 degree rotation
1878 3 = 270 degree rotation
1880 If CONFIG_LCD_ROTATION is not defined, the console will be
1881 initialized with 0degree rotation.
1885 Support drawing of RLE8-compressed bitmaps on the LCD.
1889 Enables an 'i2c edid' command which can read EDID
1890 information over I2C from an attached LCD display.
1892 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1894 If this option is set, the environment is checked for
1895 a variable "splashimage". If found, the usual display
1896 of logo, copyright and system information on the LCD
1897 is suppressed and the BMP image at the address
1898 specified in "splashimage" is loaded instead. The
1899 console is redirected to the "nulldev", too. This
1900 allows for a "silent" boot where a splash screen is
1901 loaded very quickly after power-on.
1903 CONFIG_SPLASHIMAGE_GUARD
1905 If this option is set, then U-Boot will prevent the environment
1906 variable "splashimage" from being set to a problematic address
1907 (see doc/README.displaying-bmps).
1908 This option is useful for targets where, due to alignment
1909 restrictions, an improperly aligned BMP image will cause a data
1910 abort. If you think you will not have problems with unaligned
1911 accesses (for example because your toolchain prevents them)
1912 there is no need to set this option.
1914 CONFIG_SPLASH_SCREEN_ALIGN
1916 If this option is set the splash image can be freely positioned
1917 on the screen. Environment variable "splashpos" specifies the
1918 position as "x,y". If a positive number is given it is used as
1919 number of pixel from left/top. If a negative number is given it
1920 is used as number of pixel from right/bottom. You can also
1921 specify 'm' for centering the image.
1924 setenv splashpos m,m
1925 => image at center of screen
1927 setenv splashpos 30,20
1928 => image at x = 30 and y = 20
1930 setenv splashpos -10,m
1931 => vertically centered image
1932 at x = dspWidth - bmpWidth - 9
1934 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1936 If this option is set, additionally to standard BMP
1937 images, gzipped BMP images can be displayed via the
1938 splashscreen support or the bmp command.
1940 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1942 If this option is set, 8-bit RLE compressed BMP images
1943 can be displayed via the splashscreen support or the
1946 - Do compressing for memory range:
1949 If this option is set, it would use zlib deflate method
1950 to compress the specified memory at its best effort.
1952 - Compression support:
1955 Enabled by default to support gzip compressed images.
1959 If this option is set, support for bzip2 compressed
1960 images is included. If not, only uncompressed and gzip
1961 compressed images are supported.
1963 NOTE: the bzip2 algorithm requires a lot of RAM, so
1964 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1969 If this option is set, support for lzma compressed
1972 Note: The LZMA algorithm adds between 2 and 4KB of code and it
1973 requires an amount of dynamic memory that is given by the
1976 (1846 + 768 << (lc + lp)) * sizeof(uint16)
1978 Where lc and lp stand for, respectively, Literal context bits
1979 and Literal pos bits.
1981 This value is upper-bounded by 14MB in the worst case. Anyway,
1982 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
1983 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
1984 a very small buffer.
1986 Use the lzmainfo tool to determinate the lc and lp values and
1987 then calculate the amount of needed dynamic memory (ensuring
1988 the appropriate CONFIG_SYS_MALLOC_LEN value).
1992 If this option is set, support for LZO compressed images
1998 The address of PHY on MII bus.
2000 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
2002 The clock frequency of the MII bus
2006 If this option is set, support for speed/duplex
2007 detection of gigabit PHY is included.
2009 CONFIG_PHY_RESET_DELAY
2011 Some PHY like Intel LXT971A need extra delay after
2012 reset before any MII register access is possible.
2013 For such PHY, set this option to the usec delay
2014 required. (minimum 300usec for LXT971A)
2016 CONFIG_PHY_CMD_DELAY (ppc4xx)
2018 Some PHY like Intel LXT971A need extra delay after
2019 command issued before MII status register can be read
2024 Define a default value for the IP address to use for
2025 the default Ethernet interface, in case this is not
2026 determined through e.g. bootp.
2027 (Environment variable "ipaddr")
2029 - Server IP address:
2032 Defines a default value for the IP address of a TFTP
2033 server to contact when using the "tftboot" command.
2034 (Environment variable "serverip")
2036 CONFIG_KEEP_SERVERADDR
2038 Keeps the server's MAC address, in the env 'serveraddr'
2039 for passing to bootargs (like Linux's netconsole option)
2041 - Gateway IP address:
2044 Defines a default value for the IP address of the
2045 default router where packets to other networks are
2047 (Environment variable "gatewayip")
2052 Defines a default value for the subnet mask (or
2053 routing prefix) which is used to determine if an IP
2054 address belongs to the local subnet or needs to be
2055 forwarded through a router.
2056 (Environment variable "netmask")
2058 - Multicast TFTP Mode:
2061 Defines whether you want to support multicast TFTP as per
2062 rfc-2090; for example to work with atftp. Lets lots of targets
2063 tftp down the same boot image concurrently. Note: the Ethernet
2064 driver in use must provide a function: mcast() to join/leave a
2067 - BOOTP Recovery Mode:
2068 CONFIG_BOOTP_RANDOM_DELAY
2070 If you have many targets in a network that try to
2071 boot using BOOTP, you may want to avoid that all
2072 systems send out BOOTP requests at precisely the same
2073 moment (which would happen for instance at recovery
2074 from a power failure, when all systems will try to
2075 boot, thus flooding the BOOTP server. Defining
2076 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
2077 inserted before sending out BOOTP requests. The
2078 following delays are inserted then:
2080 1st BOOTP request: delay 0 ... 1 sec
2081 2nd BOOTP request: delay 0 ... 2 sec
2082 3rd BOOTP request: delay 0 ... 4 sec
2084 BOOTP requests: delay 0 ... 8 sec
2086 CONFIG_BOOTP_ID_CACHE_SIZE
2088 BOOTP packets are uniquely identified using a 32-bit ID. The
2089 server will copy the ID from client requests to responses and
2090 U-Boot will use this to determine if it is the destination of
2091 an incoming response. Some servers will check that addresses
2092 aren't in use before handing them out (usually using an ARP
2093 ping) and therefore take up to a few hundred milliseconds to
2094 respond. Network congestion may also influence the time it
2095 takes for a response to make it back to the client. If that
2096 time is too long, U-Boot will retransmit requests. In order
2097 to allow earlier responses to still be accepted after these
2098 retransmissions, U-Boot's BOOTP client keeps a small cache of
2099 IDs. The CONFIG_BOOTP_ID_CACHE_SIZE controls the size of this
2100 cache. The default is to keep IDs for up to four outstanding
2101 requests. Increasing this will allow U-Boot to accept offers
2102 from a BOOTP client in networks with unusually high latency.
2104 - DHCP Advanced Options:
2105 You can fine tune the DHCP functionality by defining
2106 CONFIG_BOOTP_* symbols:
2108 CONFIG_BOOTP_SUBNETMASK
2109 CONFIG_BOOTP_GATEWAY
2110 CONFIG_BOOTP_HOSTNAME
2111 CONFIG_BOOTP_NISDOMAIN
2112 CONFIG_BOOTP_BOOTPATH
2113 CONFIG_BOOTP_BOOTFILESIZE
2116 CONFIG_BOOTP_SEND_HOSTNAME
2117 CONFIG_BOOTP_NTPSERVER
2118 CONFIG_BOOTP_TIMEOFFSET
2119 CONFIG_BOOTP_VENDOREX
2120 CONFIG_BOOTP_MAY_FAIL
2122 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
2123 environment variable, not the BOOTP server.
2125 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
2126 after the configured retry count, the call will fail
2127 instead of starting over. This can be used to fail over
2128 to Link-local IP address configuration if the DHCP server
2131 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
2132 serverip from a DHCP server, it is possible that more
2133 than one DNS serverip is offered to the client.
2134 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
2135 serverip will be stored in the additional environment
2136 variable "dnsip2". The first DNS serverip is always
2137 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
2140 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
2141 to do a dynamic update of a DNS server. To do this, they
2142 need the hostname of the DHCP requester.
2143 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
2144 of the "hostname" environment variable is passed as
2145 option 12 to the DHCP server.
2147 CONFIG_BOOTP_DHCP_REQUEST_DELAY
2149 A 32bit value in microseconds for a delay between
2150 receiving a "DHCP Offer" and sending the "DHCP Request".
2151 This fixes a problem with certain DHCP servers that don't
2152 respond 100% of the time to a "DHCP request". E.g. On an
2153 AT91RM9200 processor running at 180MHz, this delay needed
2154 to be *at least* 15,000 usec before a Windows Server 2003
2155 DHCP server would reply 100% of the time. I recommend at
2156 least 50,000 usec to be safe. The alternative is to hope
2157 that one of the retries will be successful but note that
2158 the DHCP timeout and retry process takes a longer than
2161 - Link-local IP address negotiation:
2162 Negotiate with other link-local clients on the local network
2163 for an address that doesn't require explicit configuration.
2164 This is especially useful if a DHCP server cannot be guaranteed
2165 to exist in all environments that the device must operate.
2167 See doc/README.link-local for more information.
2170 CONFIG_CDP_DEVICE_ID
2172 The device id used in CDP trigger frames.
2174 CONFIG_CDP_DEVICE_ID_PREFIX
2176 A two character string which is prefixed to the MAC address
2181 A printf format string which contains the ascii name of
2182 the port. Normally is set to "eth%d" which sets
2183 eth0 for the first Ethernet, eth1 for the second etc.
2185 CONFIG_CDP_CAPABILITIES
2187 A 32bit integer which indicates the device capabilities;
2188 0x00000010 for a normal host which does not forwards.
2192 An ascii string containing the version of the software.
2196 An ascii string containing the name of the platform.
2200 A 32bit integer sent on the trigger.
2202 CONFIG_CDP_POWER_CONSUMPTION
2204 A 16bit integer containing the power consumption of the
2205 device in .1 of milliwatts.
2207 CONFIG_CDP_APPLIANCE_VLAN_TYPE
2209 A byte containing the id of the VLAN.
2211 - Status LED: CONFIG_STATUS_LED
2213 Several configurations allow to display the current
2214 status using a LED. For instance, the LED will blink
2215 fast while running U-Boot code, stop blinking as
2216 soon as a reply to a BOOTP request was received, and
2217 start blinking slow once the Linux kernel is running
2218 (supported by a status LED driver in the Linux
2219 kernel). Defining CONFIG_STATUS_LED enables this
2225 The status LED can be connected to a GPIO pin.
2226 In such cases, the gpio_led driver can be used as a
2227 status LED backend implementation. Define CONFIG_GPIO_LED
2228 to include the gpio_led driver in the U-Boot binary.
2230 CONFIG_GPIO_LED_INVERTED_TABLE
2231 Some GPIO connected LEDs may have inverted polarity in which
2232 case the GPIO high value corresponds to LED off state and
2233 GPIO low value corresponds to LED on state.
2234 In such cases CONFIG_GPIO_LED_INVERTED_TABLE may be defined
2235 with a list of GPIO LEDs that have inverted polarity.
2237 - CAN Support: CONFIG_CAN_DRIVER
2239 Defining CONFIG_CAN_DRIVER enables CAN driver support
2240 on those systems that support this (optional)
2241 feature, like the TQM8xxL modules.
2243 - I2C Support: CONFIG_SYS_I2C
2245 This enable the NEW i2c subsystem, and will allow you to use
2246 i2c commands at the u-boot command line (as long as you set
2247 CONFIG_CMD_I2C in CONFIG_COMMANDS) and communicate with i2c
2248 based realtime clock chips or other i2c devices. See
2249 common/cmd_i2c.c for a description of the command line
2252 ported i2c driver to the new framework:
2253 - drivers/i2c/soft_i2c.c:
2254 - activate first bus with CONFIG_SYS_I2C_SOFT define
2255 CONFIG_SYS_I2C_SOFT_SPEED and CONFIG_SYS_I2C_SOFT_SLAVE
2256 for defining speed and slave address
2257 - activate second bus with I2C_SOFT_DECLARATIONS2 define
2258 CONFIG_SYS_I2C_SOFT_SPEED_2 and CONFIG_SYS_I2C_SOFT_SLAVE_2
2259 for defining speed and slave address
2260 - activate third bus with I2C_SOFT_DECLARATIONS3 define
2261 CONFIG_SYS_I2C_SOFT_SPEED_3 and CONFIG_SYS_I2C_SOFT_SLAVE_3
2262 for defining speed and slave address
2263 - activate fourth bus with I2C_SOFT_DECLARATIONS4 define
2264 CONFIG_SYS_I2C_SOFT_SPEED_4 and CONFIG_SYS_I2C_SOFT_SLAVE_4
2265 for defining speed and slave address
2267 - drivers/i2c/fsl_i2c.c:
2268 - activate i2c driver with CONFIG_SYS_I2C_FSL
2269 define CONFIG_SYS_FSL_I2C_OFFSET for setting the register
2270 offset CONFIG_SYS_FSL_I2C_SPEED for the i2c speed and
2271 CONFIG_SYS_FSL_I2C_SLAVE for the slave addr of the first
2273 - If your board supports a second fsl i2c bus, define
2274 CONFIG_SYS_FSL_I2C2_OFFSET for the register offset
2275 CONFIG_SYS_FSL_I2C2_SPEED for the speed and
2276 CONFIG_SYS_FSL_I2C2_SLAVE for the slave address of the
2279 - drivers/i2c/tegra_i2c.c:
2280 - activate this driver with CONFIG_SYS_I2C_TEGRA
2281 - This driver adds 4 i2c buses with a fix speed from
2282 100000 and the slave addr 0!
2284 - drivers/i2c/ppc4xx_i2c.c
2285 - activate this driver with CONFIG_SYS_I2C_PPC4XX
2286 - CONFIG_SYS_I2C_PPC4XX_CH0 activate hardware channel 0
2287 - CONFIG_SYS_I2C_PPC4XX_CH1 activate hardware channel 1
2289 - drivers/i2c/i2c_mxc.c
2290 - activate this driver with CONFIG_SYS_I2C_MXC
2291 - enable bus 1 with CONFIG_SYS_I2C_MXC_I2C1
2292 - enable bus 2 with CONFIG_SYS_I2C_MXC_I2C2
2293 - enable bus 3 with CONFIG_SYS_I2C_MXC_I2C3
2294 - enable bus 4 with CONFIG_SYS_I2C_MXC_I2C4
2295 - define speed for bus 1 with CONFIG_SYS_MXC_I2C1_SPEED
2296 - define slave for bus 1 with CONFIG_SYS_MXC_I2C1_SLAVE
2297 - define speed for bus 2 with CONFIG_SYS_MXC_I2C2_SPEED
2298 - define slave for bus 2 with CONFIG_SYS_MXC_I2C2_SLAVE
2299 - define speed for bus 3 with CONFIG_SYS_MXC_I2C3_SPEED
2300 - define slave for bus 3 with CONFIG_SYS_MXC_I2C3_SLAVE
2301 - define speed for bus 4 with CONFIG_SYS_MXC_I2C4_SPEED
2302 - define slave for bus 4 with CONFIG_SYS_MXC_I2C4_SLAVE
2303 If those defines are not set, default value is 100000
2304 for speed, and 0 for slave.
2306 - drivers/i2c/rcar_i2c.c:
2307 - activate this driver with CONFIG_SYS_I2C_RCAR
2308 - This driver adds 4 i2c buses
2310 - CONFIG_SYS_RCAR_I2C0_BASE for setting the register channel 0
2311 - CONFIG_SYS_RCAR_I2C0_SPEED for for the speed channel 0
2312 - CONFIG_SYS_RCAR_I2C1_BASE for setting the register channel 1
2313 - CONFIG_SYS_RCAR_I2C1_SPEED for for the speed channel 1
2314 - CONFIG_SYS_RCAR_I2C2_BASE for setting the register channel 2
2315 - CONFIG_SYS_RCAR_I2C2_SPEED for for the speed channel 2
2316 - CONFIG_SYS_RCAR_I2C3_BASE for setting the register channel 3
2317 - CONFIG_SYS_RCAR_I2C3_SPEED for for the speed channel 3
2318 - CONFIF_SYS_RCAR_I2C_NUM_CONTROLLERS for number of i2c buses
2320 - drivers/i2c/sh_i2c.c:
2321 - activate this driver with CONFIG_SYS_I2C_SH
2322 - This driver adds from 2 to 5 i2c buses
2324 - CONFIG_SYS_I2C_SH_BASE0 for setting the register channel 0
2325 - CONFIG_SYS_I2C_SH_SPEED0 for for the speed channel 0
2326 - CONFIG_SYS_I2C_SH_BASE1 for setting the register channel 1
2327 - CONFIG_SYS_I2C_SH_SPEED1 for for the speed channel 1
2328 - CONFIG_SYS_I2C_SH_BASE2 for setting the register channel 2
2329 - CONFIG_SYS_I2C_SH_SPEED2 for for the speed channel 2
2330 - CONFIG_SYS_I2C_SH_BASE3 for setting the register channel 3
2331 - CONFIG_SYS_I2C_SH_SPEED3 for for the speed channel 3
2332 - CONFIG_SYS_I2C_SH_BASE4 for setting the register channel 4
2333 - CONFIG_SYS_I2C_SH_SPEED4 for for the speed channel 4
2334 - CONFIG_SYS_I2C_SH_BASE5 for setting the register channel 5
2335 - CONFIG_SYS_I2C_SH_SPEED5 for for the speed channel 5
2336 - CONFIG_SYS_I2C_SH_NUM_CONTROLLERS for number of i2c buses
2338 - drivers/i2c/omap24xx_i2c.c
2339 - activate this driver with CONFIG_SYS_I2C_OMAP24XX
2340 - CONFIG_SYS_OMAP24_I2C_SPEED speed channel 0
2341 - CONFIG_SYS_OMAP24_I2C_SLAVE slave addr channel 0
2342 - CONFIG_SYS_OMAP24_I2C_SPEED1 speed channel 1
2343 - CONFIG_SYS_OMAP24_I2C_SLAVE1 slave addr channel 1
2344 - CONFIG_SYS_OMAP24_I2C_SPEED2 speed channel 2
2345 - CONFIG_SYS_OMAP24_I2C_SLAVE2 slave addr channel 2
2346 - CONFIG_SYS_OMAP24_I2C_SPEED3 speed channel 3
2347 - CONFIG_SYS_OMAP24_I2C_SLAVE3 slave addr channel 3
2348 - CONFIG_SYS_OMAP24_I2C_SPEED4 speed channel 4
2349 - CONFIG_SYS_OMAP24_I2C_SLAVE4 slave addr channel 4
2351 - drivers/i2c/zynq_i2c.c
2352 - activate this driver with CONFIG_SYS_I2C_ZYNQ
2353 - set CONFIG_SYS_I2C_ZYNQ_SPEED for speed setting
2354 - set CONFIG_SYS_I2C_ZYNQ_SLAVE for slave addr
2356 - drivers/i2c/s3c24x0_i2c.c:
2357 - activate this driver with CONFIG_SYS_I2C_S3C24X0
2358 - This driver adds i2c buses (11 for Exynos5250, Exynos5420
2359 9 i2c buses for Exynos4 and 1 for S3C24X0 SoCs from Samsung)
2360 with a fix speed from 100000 and the slave addr 0!
2362 - drivers/i2c/ihs_i2c.c
2363 - activate this driver with CONFIG_SYS_I2C_IHS
2364 - CONFIG_SYS_I2C_IHS_CH0 activate hardware channel 0
2365 - CONFIG_SYS_I2C_IHS_SPEED_0 speed channel 0
2366 - CONFIG_SYS_I2C_IHS_SLAVE_0 slave addr channel 0
2367 - CONFIG_SYS_I2C_IHS_CH1 activate hardware channel 1
2368 - CONFIG_SYS_I2C_IHS_SPEED_1 speed channel 1
2369 - CONFIG_SYS_I2C_IHS_SLAVE_1 slave addr channel 1
2370 - CONFIG_SYS_I2C_IHS_CH2 activate hardware channel 2
2371 - CONFIG_SYS_I2C_IHS_SPEED_2 speed channel 2
2372 - CONFIG_SYS_I2C_IHS_SLAVE_2 slave addr channel 2
2373 - CONFIG_SYS_I2C_IHS_CH3 activate hardware channel 3
2374 - CONFIG_SYS_I2C_IHS_SPEED_3 speed channel 3
2375 - CONFIG_SYS_I2C_IHS_SLAVE_3 slave addr channel 3
2376 - activate dual channel with CONFIG_SYS_I2C_IHS_DUAL
2377 - CONFIG_SYS_I2C_IHS_SPEED_0_1 speed channel 0_1
2378 - CONFIG_SYS_I2C_IHS_SLAVE_0_1 slave addr channel 0_1
2379 - CONFIG_SYS_I2C_IHS_SPEED_1_1 speed channel 1_1
2380 - CONFIG_SYS_I2C_IHS_SLAVE_1_1 slave addr channel 1_1
2381 - CONFIG_SYS_I2C_IHS_SPEED_2_1 speed channel 2_1
2382 - CONFIG_SYS_I2C_IHS_SLAVE_2_1 slave addr channel 2_1
2383 - CONFIG_SYS_I2C_IHS_SPEED_3_1 speed channel 3_1
2384 - CONFIG_SYS_I2C_IHS_SLAVE_3_1 slave addr channel 3_1
2388 CONFIG_SYS_NUM_I2C_BUSES
2389 Hold the number of i2c buses you want to use. If you
2390 don't use/have i2c muxes on your i2c bus, this
2391 is equal to CONFIG_SYS_NUM_I2C_ADAPTERS, and you can
2394 CONFIG_SYS_I2C_DIRECT_BUS
2395 define this, if you don't use i2c muxes on your hardware.
2396 if CONFIG_SYS_I2C_MAX_HOPS is not defined or == 0 you can
2399 CONFIG_SYS_I2C_MAX_HOPS
2400 define how many muxes are maximal consecutively connected
2401 on one i2c bus. If you not use i2c muxes, omit this
2404 CONFIG_SYS_I2C_BUSES
2405 hold a list of buses you want to use, only used if
2406 CONFIG_SYS_I2C_DIRECT_BUS is not defined, for example
2407 a board with CONFIG_SYS_I2C_MAX_HOPS = 1 and
2408 CONFIG_SYS_NUM_I2C_BUSES = 9:
2410 CONFIG_SYS_I2C_BUSES {{0, {I2C_NULL_HOP}}, \
2411 {0, {{I2C_MUX_PCA9547, 0x70, 1}}}, \
2412 {0, {{I2C_MUX_PCA9547, 0x70, 2}}}, \
2413 {0, {{I2C_MUX_PCA9547, 0x70, 3}}}, \
2414 {0, {{I2C_MUX_PCA9547, 0x70, 4}}}, \
2415 {0, {{I2C_MUX_PCA9547, 0x70, 5}}}, \
2416 {1, {I2C_NULL_HOP}}, \
2417 {1, {{I2C_MUX_PCA9544, 0x72, 1}}}, \
2418 {1, {{I2C_MUX_PCA9544, 0x72, 2}}}, \
2422 bus 0 on adapter 0 without a mux
2423 bus 1 on adapter 0 with a PCA9547 on address 0x70 port 1
2424 bus 2 on adapter 0 with a PCA9547 on address 0x70 port 2
2425 bus 3 on adapter 0 with a PCA9547 on address 0x70 port 3
2426 bus 4 on adapter 0 with a PCA9547 on address 0x70 port 4
2427 bus 5 on adapter 0 with a PCA9547 on address 0x70 port 5
2428 bus 6 on adapter 1 without a mux
2429 bus 7 on adapter 1 with a PCA9544 on address 0x72 port 1
2430 bus 8 on adapter 1 with a PCA9544 on address 0x72 port 2
2432 If you do not have i2c muxes on your board, omit this define.
2434 - Legacy I2C Support: CONFIG_HARD_I2C
2436 NOTE: It is intended to move drivers to CONFIG_SYS_I2C which
2437 provides the following compelling advantages:
2439 - more than one i2c adapter is usable
2440 - approved multibus support
2441 - better i2c mux support
2443 ** Please consider updating your I2C driver now. **
2445 These enable legacy I2C serial bus commands. Defining
2446 CONFIG_HARD_I2C will include the appropriate I2C driver
2447 for the selected CPU.
2449 This will allow you to use i2c commands at the u-boot
2450 command line (as long as you set CONFIG_CMD_I2C in
2451 CONFIG_COMMANDS) and communicate with i2c based realtime
2452 clock chips. See common/cmd_i2c.c for a description of the
2453 command line interface.
2455 CONFIG_HARD_I2C selects a hardware I2C controller.
2457 There are several other quantities that must also be
2458 defined when you define CONFIG_HARD_I2C.
2460 In both cases you will need to define CONFIG_SYS_I2C_SPEED
2461 to be the frequency (in Hz) at which you wish your i2c bus
2462 to run and CONFIG_SYS_I2C_SLAVE to be the address of this node (ie
2463 the CPU's i2c node address).
2465 Now, the u-boot i2c code for the mpc8xx
2466 (arch/powerpc/cpu/mpc8xx/i2c.c) sets the CPU up as a master node
2467 and so its address should therefore be cleared to 0 (See,
2468 eg, MPC823e User's Manual p.16-473). So, set
2469 CONFIG_SYS_I2C_SLAVE to 0.
2471 CONFIG_SYS_I2C_INIT_MPC5XXX
2473 When a board is reset during an i2c bus transfer
2474 chips might think that the current transfer is still
2475 in progress. Reset the slave devices by sending start
2476 commands until the slave device responds.
2478 That's all that's required for CONFIG_HARD_I2C.
2480 If you use the software i2c interface (CONFIG_SYS_I2C_SOFT)
2481 then the following macros need to be defined (examples are
2482 from include/configs/lwmon.h):
2486 (Optional). Any commands necessary to enable the I2C
2487 controller or configure ports.
2489 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
2493 (Only for MPC8260 CPU). The I/O port to use (the code
2494 assumes both bits are on the same port). Valid values
2495 are 0..3 for ports A..D.
2499 The code necessary to make the I2C data line active
2500 (driven). If the data line is open collector, this
2503 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
2507 The code necessary to make the I2C data line tri-stated
2508 (inactive). If the data line is open collector, this
2511 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
2515 Code that returns true if the I2C data line is high,
2518 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
2522 If <bit> is true, sets the I2C data line high. If it
2523 is false, it clears it (low).
2525 eg: #define I2C_SDA(bit) \
2526 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
2527 else immr->im_cpm.cp_pbdat &= ~PB_SDA
2531 If <bit> is true, sets the I2C clock line high. If it
2532 is false, it clears it (low).
2534 eg: #define I2C_SCL(bit) \
2535 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
2536 else immr->im_cpm.cp_pbdat &= ~PB_SCL
2540 This delay is invoked four times per clock cycle so this
2541 controls the rate of data transfer. The data rate thus
2542 is 1 / (I2C_DELAY * 4). Often defined to be something
2545 #define I2C_DELAY udelay(2)
2547 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
2549 If your arch supports the generic GPIO framework (asm/gpio.h),
2550 then you may alternatively define the two GPIOs that are to be
2551 used as SCL / SDA. Any of the previous I2C_xxx macros will
2552 have GPIO-based defaults assigned to them as appropriate.
2554 You should define these to the GPIO value as given directly to
2555 the generic GPIO functions.
2557 CONFIG_SYS_I2C_INIT_BOARD
2559 When a board is reset during an i2c bus transfer
2560 chips might think that the current transfer is still
2561 in progress. On some boards it is possible to access
2562 the i2c SCLK line directly, either by using the
2563 processor pin as a GPIO or by having a second pin
2564 connected to the bus. If this option is defined a
2565 custom i2c_init_board() routine in boards/xxx/board.c
2566 is run early in the boot sequence.
2568 CONFIG_SYS_I2C_BOARD_LATE_INIT
2570 An alternative to CONFIG_SYS_I2C_INIT_BOARD. If this option is
2571 defined a custom i2c_board_late_init() routine in
2572 boards/xxx/board.c is run AFTER the operations in i2c_init()
2573 is completed. This callpoint can be used to unreset i2c bus
2574 using CPU i2c controller register accesses for CPUs whose i2c
2575 controller provide such a method. It is called at the end of
2576 i2c_init() to allow i2c_init operations to setup the i2c bus
2577 controller on the CPU (e.g. setting bus speed & slave address).
2579 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
2581 This option enables configuration of bi_iic_fast[] flags
2582 in u-boot bd_info structure based on u-boot environment
2583 variable "i2cfast". (see also i2cfast)
2585 CONFIG_I2C_MULTI_BUS
2587 This option allows the use of multiple I2C buses, each of which
2588 must have a controller. At any point in time, only one bus is
2589 active. To switch to a different bus, use the 'i2c dev' command.
2590 Note that bus numbering is zero-based.
2592 CONFIG_SYS_I2C_NOPROBES
2594 This option specifies a list of I2C devices that will be skipped
2595 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
2596 is set, specify a list of bus-device pairs. Otherwise, specify
2597 a 1D array of device addresses
2600 #undef CONFIG_I2C_MULTI_BUS
2601 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
2603 will skip addresses 0x50 and 0x68 on a board with one I2C bus
2605 #define CONFIG_I2C_MULTI_BUS
2606 #define CONFIG_SYS_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
2608 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
2610 CONFIG_SYS_SPD_BUS_NUM
2612 If defined, then this indicates the I2C bus number for DDR SPD.
2613 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
2615 CONFIG_SYS_RTC_BUS_NUM
2617 If defined, then this indicates the I2C bus number for the RTC.
2618 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
2620 CONFIG_SYS_DTT_BUS_NUM
2622 If defined, then this indicates the I2C bus number for the DTT.
2623 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
2625 CONFIG_SYS_I2C_DTT_ADDR:
2627 If defined, specifies the I2C address of the DTT device.
2628 If not defined, then U-Boot uses predefined value for
2629 specified DTT device.
2631 CONFIG_SOFT_I2C_READ_REPEATED_START
2633 defining this will force the i2c_read() function in
2634 the soft_i2c driver to perform an I2C repeated start
2635 between writing the address pointer and reading the
2636 data. If this define is omitted the default behaviour
2637 of doing a stop-start sequence will be used. Most I2C
2638 devices can use either method, but some require one or
2641 - SPI Support: CONFIG_SPI
2643 Enables SPI driver (so far only tested with
2644 SPI EEPROM, also an instance works with Crystal A/D and
2645 D/As on the SACSng board)
2649 Enables the driver for SPI controller on SuperH. Currently
2650 only SH7757 is supported.
2654 Enables a software (bit-bang) SPI driver rather than
2655 using hardware support. This is a general purpose
2656 driver that only requires three general I/O port pins
2657 (two outputs, one input) to function. If this is
2658 defined, the board configuration must define several
2659 SPI configuration items (port pins to use, etc). For
2660 an example, see include/configs/sacsng.h.
2664 Enables a hardware SPI driver for general-purpose reads
2665 and writes. As with CONFIG_SOFT_SPI, the board configuration
2666 must define a list of chip-select function pointers.
2667 Currently supported on some MPC8xxx processors. For an
2668 example, see include/configs/mpc8349emds.h.
2672 Enables the driver for the SPI controllers on i.MX and MXC
2673 SoCs. Currently i.MX31/35/51 are supported.
2675 CONFIG_SYS_SPI_MXC_WAIT
2676 Timeout for waiting until spi transfer completed.
2677 default: (CONFIG_SYS_HZ/100) /* 10 ms */
2679 - FPGA Support: CONFIG_FPGA
2681 Enables FPGA subsystem.
2683 CONFIG_FPGA_<vendor>
2685 Enables support for specific chip vendors.
2688 CONFIG_FPGA_<family>
2690 Enables support for FPGA family.
2691 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
2695 Specify the number of FPGA devices to support.
2697 CONFIG_CMD_FPGA_LOADMK
2699 Enable support for fpga loadmk command
2701 CONFIG_CMD_FPGA_LOADP
2703 Enable support for fpga loadp command - load partial bitstream
2705 CONFIG_CMD_FPGA_LOADBP
2707 Enable support for fpga loadbp command - load partial bitstream
2710 CONFIG_SYS_FPGA_PROG_FEEDBACK
2712 Enable printing of hash marks during FPGA configuration.
2714 CONFIG_SYS_FPGA_CHECK_BUSY
2716 Enable checks on FPGA configuration interface busy
2717 status by the configuration function. This option
2718 will require a board or device specific function to
2723 If defined, a function that provides delays in the FPGA
2724 configuration driver.
2726 CONFIG_SYS_FPGA_CHECK_CTRLC
2727 Allow Control-C to interrupt FPGA configuration
2729 CONFIG_SYS_FPGA_CHECK_ERROR
2731 Check for configuration errors during FPGA bitfile
2732 loading. For example, abort during Virtex II
2733 configuration if the INIT_B line goes low (which
2734 indicated a CRC error).
2736 CONFIG_SYS_FPGA_WAIT_INIT
2738 Maximum time to wait for the INIT_B line to de-assert
2739 after PROB_B has been de-asserted during a Virtex II
2740 FPGA configuration sequence. The default time is 500
2743 CONFIG_SYS_FPGA_WAIT_BUSY
2745 Maximum time to wait for BUSY to de-assert during
2746 Virtex II FPGA configuration. The default is 5 ms.
2748 CONFIG_SYS_FPGA_WAIT_CONFIG
2750 Time to wait after FPGA configuration. The default is
2753 - Configuration Management:
2756 Some SoCs need special image types (e.g. U-Boot binary
2757 with a special header) as build targets. By defining
2758 CONFIG_BUILD_TARGET in the SoC / board header, this
2759 special image will be automatically built upon calling
2764 If defined, this string will be added to the U-Boot
2765 version information (U_BOOT_VERSION)
2767 - Vendor Parameter Protection:
2769 U-Boot considers the values of the environment
2770 variables "serial#" (Board Serial Number) and
2771 "ethaddr" (Ethernet Address) to be parameters that
2772 are set once by the board vendor / manufacturer, and
2773 protects these variables from casual modification by
2774 the user. Once set, these variables are read-only,
2775 and write or delete attempts are rejected. You can
2776 change this behaviour:
2778 If CONFIG_ENV_OVERWRITE is #defined in your config
2779 file, the write protection for vendor parameters is
2780 completely disabled. Anybody can change or delete
2783 Alternatively, if you define _both_ an ethaddr in the
2784 default env _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2785 Ethernet address is installed in the environment,
2786 which can be changed exactly ONCE by the user. [The
2787 serial# is unaffected by this, i. e. it remains
2790 The same can be accomplished in a more flexible way
2791 for any variable by configuring the type of access
2792 to allow for those variables in the ".flags" variable
2793 or define CONFIG_ENV_FLAGS_LIST_STATIC.
2798 Define this variable to enable the reservation of
2799 "protected RAM", i. e. RAM which is not overwritten
2800 by U-Boot. Define CONFIG_PRAM to hold the number of
2801 kB you want to reserve for pRAM. You can overwrite
2802 this default value by defining an environment
2803 variable "pram" to the number of kB you want to
2804 reserve. Note that the board info structure will
2805 still show the full amount of RAM. If pRAM is
2806 reserved, a new environment variable "mem" will
2807 automatically be defined to hold the amount of
2808 remaining RAM in a form that can be passed as boot
2809 argument to Linux, for instance like that:
2811 setenv bootargs ... mem=\${mem}
2814 This way you can tell Linux not to use this memory,
2815 either, which results in a memory region that will
2816 not be affected by reboots.
2818 *WARNING* If your board configuration uses automatic
2819 detection of the RAM size, you must make sure that
2820 this memory test is non-destructive. So far, the
2821 following board configurations are known to be
2824 IVMS8, IVML24, SPD8xx, TQM8xxL,
2825 HERMES, IP860, RPXlite, LWMON,
2828 - Access to physical memory region (> 4GB)
2829 Some basic support is provided for operations on memory not
2830 normally accessible to U-Boot - e.g. some architectures
2831 support access to more than 4GB of memory on 32-bit
2832 machines using physical address extension or similar.
2833 Define CONFIG_PHYSMEM to access this basic support, which
2834 currently only supports clearing the memory.
2839 Define this variable to stop the system in case of a
2840 fatal error, so that you have to reset it manually.
2841 This is probably NOT a good idea for an embedded
2842 system where you want the system to reboot
2843 automatically as fast as possible, but it may be
2844 useful during development since you can try to debug
2845 the conditions that lead to the situation.
2847 CONFIG_NET_RETRY_COUNT
2849 This variable defines the number of retries for
2850 network operations like ARP, RARP, TFTP, or BOOTP
2851 before giving up the operation. If not defined, a
2852 default value of 5 is used.
2856 Timeout waiting for an ARP reply in milliseconds.
2860 Timeout in milliseconds used in NFS protocol.
2861 If you encounter "ERROR: Cannot umount" in nfs command,
2862 try longer timeout such as
2863 #define CONFIG_NFS_TIMEOUT 10000UL
2865 - Command Interpreter:
2866 CONFIG_AUTO_COMPLETE
2868 Enable auto completion of commands using TAB.
2870 CONFIG_SYS_PROMPT_HUSH_PS2
2872 This defines the secondary prompt string, which is
2873 printed when the command interpreter needs more input
2874 to complete a command. Usually "> ".
2878 In the current implementation, the local variables
2879 space and global environment variables space are
2880 separated. Local variables are those you define by
2881 simply typing `name=value'. To access a local
2882 variable later on, you have write `$name' or
2883 `${name}'; to execute the contents of a variable
2884 directly type `$name' at the command prompt.
2886 Global environment variables are those you use
2887 setenv/printenv to work with. To run a command stored
2888 in such a variable, you need to use the run command,
2889 and you must not use the '$' sign to access them.
2891 To store commands and special characters in a
2892 variable, please use double quotation marks
2893 surrounding the whole text of the variable, instead
2894 of the backslashes before semicolons and special
2897 - Command Line Editing and History:
2898 CONFIG_CMDLINE_EDITING
2900 Enable editing and History functions for interactive
2901 command line input operations
2903 - Command Line PS1/PS2 support:
2904 CONFIG_CMDLINE_PS_SUPPORT
2906 Enable support for changing the command prompt string
2907 at run-time. Only static string is supported so far.
2908 The string is obtained from environment variables PS1
2911 - Default Environment:
2912 CONFIG_EXTRA_ENV_SETTINGS
2914 Define this to contain any number of null terminated
2915 strings (variable = value pairs) that will be part of
2916 the default environment compiled into the boot image.
2918 For example, place something like this in your
2919 board's config file:
2921 #define CONFIG_EXTRA_ENV_SETTINGS \
2925 Warning: This method is based on knowledge about the
2926 internal format how the environment is stored by the
2927 U-Boot code. This is NOT an official, exported
2928 interface! Although it is unlikely that this format
2929 will change soon, there is no guarantee either.
2930 You better know what you are doing here.
2932 Note: overly (ab)use of the default environment is
2933 discouraged. Make sure to check other ways to preset
2934 the environment like the "source" command or the
2937 CONFIG_ENV_VARS_UBOOT_CONFIG
2939 Define this in order to add variables describing the
2940 U-Boot build configuration to the default environment.
2941 These will be named arch, cpu, board, vendor, and soc.
2943 Enabling this option will cause the following to be defined:
2951 CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG
2953 Define this in order to add variables describing certain
2954 run-time determined information about the hardware to the
2955 environment. These will be named board_name, board_rev.
2957 CONFIG_DELAY_ENVIRONMENT
2959 Normally the environment is loaded when the board is
2960 initialised so that it is available to U-Boot. This inhibits
2961 that so that the environment is not available until
2962 explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL
2963 this is instead controlled by the value of
2964 /config/load-environment.
2966 - Parallel Flash support:
2969 Traditionally U-Boot was run on systems with parallel NOR
2970 flash. This option is used to disable support for parallel NOR
2971 flash. This option should be defined if the board does not have
2974 If this option is not defined one of the generic flash drivers
2975 (e.g. CONFIG_FLASH_CFI_DRIVER or CONFIG_ST_SMI) must be
2976 selected or the board must provide an implementation of the
2977 flash API (see include/flash.h).
2979 - DataFlash Support:
2980 CONFIG_HAS_DATAFLASH
2982 Defining this option enables DataFlash features and
2983 allows to read/write in Dataflash via the standard
2986 - Serial Flash support
2989 Defining this option enables SPI flash commands
2990 'sf probe/read/write/erase/update'.
2992 Usage requires an initial 'probe' to define the serial
2993 flash parameters, followed by read/write/erase/update
2996 The following defaults may be provided by the platform
2997 to handle the common case when only a single serial
2998 flash is present on the system.
3000 CONFIG_SF_DEFAULT_BUS Bus identifier
3001 CONFIG_SF_DEFAULT_CS Chip-select
3002 CONFIG_SF_DEFAULT_MODE (see include/spi.h)
3003 CONFIG_SF_DEFAULT_SPEED in Hz
3007 Define this option to include a destructive SPI flash
3010 CONFIG_SF_DUAL_FLASH Dual flash memories
3012 Define this option to use dual flash support where two flash
3013 memories can be connected with a given cs line.
3014 Currently Xilinx Zynq qspi supports these type of connections.
3016 - SystemACE Support:
3019 Adding this option adds support for Xilinx SystemACE
3020 chips attached via some sort of local bus. The address
3021 of the chip must also be defined in the
3022 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
3024 #define CONFIG_SYSTEMACE
3025 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
3027 When SystemACE support is added, the "ace" device type
3028 becomes available to the fat commands, i.e. fatls.
3030 - TFTP Fixed UDP Port:
3033 If this is defined, the environment variable tftpsrcp
3034 is used to supply the TFTP UDP source port value.
3035 If tftpsrcp isn't defined, the normal pseudo-random port
3036 number generator is used.
3038 Also, the environment variable tftpdstp is used to supply
3039 the TFTP UDP destination port value. If tftpdstp isn't
3040 defined, the normal port 69 is used.
3042 The purpose for tftpsrcp is to allow a TFTP server to
3043 blindly start the TFTP transfer using the pre-configured
3044 target IP address and UDP port. This has the effect of
3045 "punching through" the (Windows XP) firewall, allowing
3046 the remainder of the TFTP transfer to proceed normally.
3047 A better solution is to properly configure the firewall,
3048 but sometimes that is not allowed.
3053 This enables a generic 'hash' command which can produce
3054 hashes / digests from a few algorithms (e.g. SHA1, SHA256).
3058 Enable the hash verify command (hash -v). This adds to code
3061 CONFIG_SHA1 - This option enables support of hashing using SHA1
3062 algorithm. The hash is calculated in software.
3063 CONFIG_SHA256 - This option enables support of hashing using
3064 SHA256 algorithm. The hash is calculated in software.
3065 CONFIG_SHA_HW_ACCEL - This option enables hardware acceleration
3066 for SHA1/SHA256 hashing.
3067 This affects the 'hash' command and also the
3068 hash_lookup_algo() function.
3069 CONFIG_SHA_PROG_HW_ACCEL - This option enables
3070 hardware-acceleration for SHA1/SHA256 progressive hashing.
3071 Data can be streamed in a block at a time and the hashing
3072 is performed in hardware.
3074 Note: There is also a sha1sum command, which should perhaps
3075 be deprecated in favour of 'hash sha1'.
3077 - Freescale i.MX specific commands:
3078 CONFIG_CMD_HDMIDETECT
3079 This enables 'hdmidet' command which returns true if an
3080 HDMI monitor is detected. This command is i.MX 6 specific.
3083 This enables the 'bmode' (bootmode) command for forcing
3084 a boot from specific media.
3086 This is useful for forcing the ROM's usb downloader to
3087 activate upon a watchdog reset which is nice when iterating
3088 on U-Boot. Using the reset button or running bmode normal
3089 will set it back to normal. This command currently
3090 supports i.MX53 and i.MX6.
3092 - bootcount support:
3093 CONFIG_BOOTCOUNT_LIMIT
3095 This enables the bootcounter support, see:
3096 http://www.denx.de/wiki/DULG/UBootBootCountLimit
3099 enable special bootcounter support on at91sam9xe based boards.
3101 enable special bootcounter support on blackfin based boards.
3103 enable special bootcounter support on da850 based boards.
3104 CONFIG_BOOTCOUNT_RAM
3105 enable support for the bootcounter in RAM
3106 CONFIG_BOOTCOUNT_I2C
3107 enable support for the bootcounter on an i2c (like RTC) device.
3108 CONFIG_SYS_I2C_RTC_ADDR = i2c chip address
3109 CONFIG_SYS_BOOTCOUNT_ADDR = i2c addr which is used for
3111 CONFIG_BOOTCOUNT_ALEN = address len
3113 - Show boot progress:
3114 CONFIG_SHOW_BOOT_PROGRESS
3116 Defining this option allows to add some board-
3117 specific code (calling a user-provided function
3118 "show_boot_progress(int)") that enables you to show
3119 the system's boot progress on some display (for
3120 example, some LED's) on your board. At the moment,
3121 the following checkpoints are implemented:
3124 Legacy uImage format:
3127 1 common/cmd_bootm.c before attempting to boot an image
3128 -1 common/cmd_bootm.c Image header has bad magic number
3129 2 common/cmd_bootm.c Image header has correct magic number
3130 -2 common/cmd_bootm.c Image header has bad checksum
3131 3 common/cmd_bootm.c Image header has correct checksum
3132 -3 common/cmd_bootm.c Image data has bad checksum
3133 4 common/cmd_bootm.c Image data has correct checksum
3134 -4 common/cmd_bootm.c Image is for unsupported architecture
3135 5 common/cmd_bootm.c Architecture check OK
3136 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
3137 6 common/cmd_bootm.c Image Type check OK
3138 -6 common/cmd_bootm.c gunzip uncompression error
3139 -7 common/cmd_bootm.c Unimplemented compression type
3140 7 common/cmd_bootm.c Uncompression OK
3141 8 common/cmd_bootm.c No uncompress/copy overwrite error
3142 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
3144 9 common/image.c Start initial ramdisk verification
3145 -10 common/image.c Ramdisk header has bad magic number
3146 -11 common/image.c Ramdisk header has bad checksum
3147 10 common/image.c Ramdisk header is OK
3148 -12 common/image.c Ramdisk data has bad checksum
3149 11 common/image.c Ramdisk data has correct checksum
3150 12 common/image.c Ramdisk verification complete, start loading
3151 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
3152 13 common/image.c Start multifile image verification
3153 14 common/image.c No initial ramdisk, no multifile, continue.
3155 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
3157 -30 arch/powerpc/lib/board.c Fatal error, hang the system
3158 -31 post/post.c POST test failed, detected by post_output_backlog()
3159 -32 post/post.c POST test failed, detected by post_run_single()
3161 34 common/cmd_doc.c before loading a Image from a DOC device
3162 -35 common/cmd_doc.c Bad usage of "doc" command
3163 35 common/cmd_doc.c correct usage of "doc" command
3164 -36 common/cmd_doc.c No boot device
3165 36 common/cmd_doc.c correct boot device
3166 -37 common/cmd_doc.c Unknown Chip ID on boot device
3167 37 common/cmd_doc.c correct chip ID found, device available
3168 -38 common/cmd_doc.c Read Error on boot device
3169 38 common/cmd_doc.c reading Image header from DOC device OK
3170 -39 common/cmd_doc.c Image header has bad magic number
3171 39 common/cmd_doc.c Image header has correct magic number
3172 -40 common/cmd_doc.c Error reading Image from DOC device
3173 40 common/cmd_doc.c Image header has correct magic number
3174 41 common/cmd_ide.c before loading a Image from a IDE device
3175 -42 common/cmd_ide.c Bad usage of "ide" command
3176 42 common/cmd_ide.c correct usage of "ide" command
3177 -43 common/cmd_ide.c No boot device
3178 43 common/cmd_ide.c boot device found
3179 -44 common/cmd_ide.c Device not available
3180 44 common/cmd_ide.c Device available
3181 -45 common/cmd_ide.c wrong partition selected
3182 45 common/cmd_ide.c partition selected
3183 -46 common/cmd_ide.c Unknown partition table
3184 46 common/cmd_ide.c valid partition table found
3185 -47 common/cmd_ide.c Invalid partition type
3186 47 common/cmd_ide.c correct partition type
3187 -48 common/cmd_ide.c Error reading Image Header on boot device
3188 48 common/cmd_ide.c reading Image Header from IDE device OK
3189 -49 common/cmd_ide.c Image header has bad magic number
3190 49 common/cmd_ide.c Image header has correct magic number
3191 -50 common/cmd_ide.c Image header has bad checksum
3192 50 common/cmd_ide.c Image header has correct checksum
3193 -51 common/cmd_ide.c Error reading Image from IDE device
3194 51 common/cmd_ide.c reading Image from IDE device OK
3195 52 common/cmd_nand.c before loading a Image from a NAND device
3196 -53 common/cmd_nand.c Bad usage of "nand" command
3197 53 common/cmd_nand.c correct usage of "nand" command
3198 -54 common/cmd_nand.c No boot device
3199 54 common/cmd_nand.c boot device found
3200 -55 common/cmd_nand.c Unknown Chip ID on boot device
3201 55 common/cmd_nand.c correct chip ID found, device available
3202 -56 common/cmd_nand.c Error reading Image Header on boot device
3203 56 common/cmd_nand.c reading Image Header from NAND device OK
3204 -57 common/cmd_nand.c Image header has bad magic number
3205 57 common/cmd_nand.c Image header has correct magic number
3206 -58 common/cmd_nand.c Error reading Image from NAND device
3207 58 common/cmd_nand.c reading Image from NAND device OK
3209 -60 common/env_common.c Environment has a bad CRC, using default
3211 64 net/eth.c starting with Ethernet configuration.
3212 -64 net/eth.c no Ethernet found.
3213 65 net/eth.c Ethernet found.
3215 -80 common/cmd_net.c usage wrong
3216 80 common/cmd_net.c before calling net_loop()
3217 -81 common/cmd_net.c some error in net_loop() occurred
3218 81 common/cmd_net.c net_loop() back without error
3219 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
3220 82 common/cmd_net.c trying automatic boot
3221 83 common/cmd_net.c running "source" command
3222 -83 common/cmd_net.c some error in automatic boot or "source" command
3223 84 common/cmd_net.c end without errors
3228 100 common/cmd_bootm.c Kernel FIT Image has correct format
3229 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
3230 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
3231 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
3232 102 common/cmd_bootm.c Kernel unit name specified
3233 -103 common/cmd_bootm.c Can't get kernel subimage node offset
3234 103 common/cmd_bootm.c Found configuration node
3235 104 common/cmd_bootm.c Got kernel subimage node offset
3236 -104 common/cmd_bootm.c Kernel subimage hash verification failed
3237 105 common/cmd_bootm.c Kernel subimage hash verification OK
3238 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
3239 106 common/cmd_bootm.c Architecture check OK
3240 -106 common/cmd_bootm.c Kernel subimage has wrong type
3241 107 common/cmd_bootm.c Kernel subimage type OK
3242 -107 common/cmd_bootm.c Can't get kernel subimage data/size
3243 108 common/cmd_bootm.c Got kernel subimage data/size
3244 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
3245 -109 common/cmd_bootm.c Can't get kernel subimage type
3246 -110 common/cmd_bootm.c Can't get kernel subimage comp
3247 -111 common/cmd_bootm.c Can't get kernel subimage os
3248 -112 common/cmd_bootm.c Can't get kernel subimage load address
3249 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
3251 120 common/image.c Start initial ramdisk verification
3252 -120 common/image.c Ramdisk FIT image has incorrect format
3253 121 common/image.c Ramdisk FIT image has correct format
3254 122 common/image.c No ramdisk subimage unit name, using configuration
3255 -122 common/image.c Can't get configuration for ramdisk subimage
3256 123 common/image.c Ramdisk unit name specified
3257 -124 common/image.c Can't get ramdisk subimage node offset
3258 125 common/image.c Got ramdisk subimage node offset
3259 -125 common/image.c Ramdisk subimage hash verification failed
3260 126 common/image.c Ramdisk subimage hash verification OK
3261 -126 common/image.c Ramdisk subimage for unsupported architecture
3262 127 common/image.c Architecture check OK
3263 -127 common/image.c Can't get ramdisk subimage data/size
3264 128 common/image.c Got ramdisk subimage data/size
3265 129 common/image.c Can't get ramdisk load address
3266 -129 common/image.c Got ramdisk load address
3268 -130 common/cmd_doc.c Incorrect FIT image format
3269 131 common/cmd_doc.c FIT image format OK
3271 -140 common/cmd_ide.c Incorrect FIT image format
3272 141 common/cmd_ide.c FIT image format OK
3274 -150 common/cmd_nand.c Incorrect FIT image format
3275 151 common/cmd_nand.c FIT image format OK
3277 - legacy image format:
3278 CONFIG_IMAGE_FORMAT_LEGACY
3279 enables the legacy image format support in U-Boot.
3282 enabled if CONFIG_FIT_SIGNATURE is not defined.
3284 CONFIG_DISABLE_IMAGE_LEGACY
3285 disable the legacy image format
3287 This define is introduced, as the legacy image format is
3288 enabled per default for backward compatibility.
3290 - FIT image support:
3291 CONFIG_FIT_DISABLE_SHA256
3292 Supporting SHA256 hashes has quite an impact on binary size.
3293 For constrained systems sha256 hash support can be disabled
3296 TODO(sjg@chromium.org): Adjust this option to be positive,
3297 and move it to Kconfig
3299 - Standalone program support:
3300 CONFIG_STANDALONE_LOAD_ADDR
3302 This option defines a board specific value for the
3303 address where standalone program gets loaded, thus
3304 overwriting the architecture dependent default
3307 - Frame Buffer Address:
3310 Define CONFIG_FB_ADDR if you want to use specific
3311 address for frame buffer. This is typically the case
3312 when using a graphics controller has separate video
3313 memory. U-Boot will then place the frame buffer at
3314 the given address instead of dynamically reserving it
3315 in system RAM by calling lcd_setmem(), which grabs
3316 the memory for the frame buffer depending on the
3317 configured panel size.
3319 Please see board_init_f function.
3321 - Automatic software updates via TFTP server
3323 CONFIG_UPDATE_TFTP_CNT_MAX
3324 CONFIG_UPDATE_TFTP_MSEC_MAX
3326 These options enable and control the auto-update feature;
3327 for a more detailed description refer to doc/README.update.
3329 - MTD Support (mtdparts command, UBI support)
3332 Adds the MTD device infrastructure from the Linux kernel.
3333 Needed for mtdparts command support.
3335 CONFIG_MTD_PARTITIONS
3337 Adds the MTD partitioning infrastructure from the Linux
3338 kernel. Needed for UBI support.
3343 Adds commands for interacting with MTD partitions formatted
3344 with the UBI flash translation layer
3346 Requires also defining CONFIG_RBTREE
3348 CONFIG_UBI_SILENCE_MSG
3350 Make the verbose messages from UBI stop printing. This leaves
3351 warnings and errors enabled.
3354 CONFIG_MTD_UBI_WL_THRESHOLD
3355 This parameter defines the maximum difference between the highest
3356 erase counter value and the lowest erase counter value of eraseblocks
3357 of UBI devices. When this threshold is exceeded, UBI starts performing
3358 wear leveling by means of moving data from eraseblock with low erase
3359 counter to eraseblocks with high erase counter.
3361 The default value should be OK for SLC NAND flashes, NOR flashes and
3362 other flashes which have eraseblock life-cycle 100000 or more.
3363 However, in case of MLC NAND flashes which typically have eraseblock
3364 life-cycle less than 10000, the threshold should be lessened (e.g.,
3365 to 128 or 256, although it does not have to be power of 2).
3369 CONFIG_MTD_UBI_BEB_LIMIT
3370 This option specifies the maximum bad physical eraseblocks UBI
3371 expects on the MTD device (per 1024 eraseblocks). If the
3372 underlying flash does not admit of bad eraseblocks (e.g. NOR
3373 flash), this value is ignored.
3375 NAND datasheets often specify the minimum and maximum NVM
3376 (Number of Valid Blocks) for the flashes' endurance lifetime.
3377 The maximum expected bad eraseblocks per 1024 eraseblocks
3378 then can be calculated as "1024 * (1 - MinNVB / MaxNVB)",
3379 which gives 20 for most NANDs (MaxNVB is basically the total
3380 count of eraseblocks on the chip).
3382 To put it differently, if this value is 20, UBI will try to
3383 reserve about 1.9% of physical eraseblocks for bad blocks
3384 handling. And that will be 1.9% of eraseblocks on the entire
3385 NAND chip, not just the MTD partition UBI attaches. This means
3386 that if you have, say, a NAND flash chip admits maximum 40 bad
3387 eraseblocks, and it is split on two MTD partitions of the same
3388 size, UBI will reserve 40 eraseblocks when attaching a
3393 CONFIG_MTD_UBI_FASTMAP
3394 Fastmap is a mechanism which allows attaching an UBI device
3395 in nearly constant time. Instead of scanning the whole MTD device it
3396 only has to locate a checkpoint (called fastmap) on the device.
3397 The on-flash fastmap contains all information needed to attach
3398 the device. Using fastmap makes only sense on large devices where
3399 attaching by scanning takes long. UBI will not automatically install
3400 a fastmap on old images, but you can set the UBI parameter
3401 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT to 1 if you want so. Please note
3402 that fastmap-enabled images are still usable with UBI implementations
3403 without fastmap support. On typical flash devices the whole fastmap
3404 fits into one PEB. UBI will reserve PEBs to hold two fastmaps.
3406 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT
3407 Set this parameter to enable fastmap automatically on images
3411 CONFIG_MTD_UBI_FM_DEBUG
3412 Enable UBI fastmap debug
3418 Adds commands for interacting with UBI volumes formatted as
3419 UBIFS. UBIFS is read-only in u-boot.
3421 Requires UBI support as well as CONFIG_LZO
3423 CONFIG_UBIFS_SILENCE_MSG
3425 Make the verbose messages from UBIFS stop printing. This leaves
3426 warnings and errors enabled.
3430 Enable building of SPL globally.
3433 LDSCRIPT for linking the SPL binary.
3435 CONFIG_SPL_MAX_FOOTPRINT
3436 Maximum size in memory allocated to the SPL, BSS included.
3437 When defined, the linker checks that the actual memory
3438 used by SPL from _start to __bss_end does not exceed it.
3439 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3440 must not be both defined at the same time.
3443 Maximum size of the SPL image (text, data, rodata, and
3444 linker lists sections), BSS excluded.
3445 When defined, the linker checks that the actual size does
3448 CONFIG_SPL_TEXT_BASE
3449 TEXT_BASE for linking the SPL binary.
3451 CONFIG_SPL_RELOC_TEXT_BASE
3452 Address to relocate to. If unspecified, this is equal to
3453 CONFIG_SPL_TEXT_BASE (i.e. no relocation is done).
3455 CONFIG_SPL_BSS_START_ADDR
3456 Link address for the BSS within the SPL binary.
3458 CONFIG_SPL_BSS_MAX_SIZE
3459 Maximum size in memory allocated to the SPL BSS.
3460 When defined, the linker checks that the actual memory used
3461 by SPL from __bss_start to __bss_end does not exceed it.
3462 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3463 must not be both defined at the same time.
3466 Adress of the start of the stack SPL will use
3468 CONFIG_SPL_PANIC_ON_RAW_IMAGE
3469 When defined, SPL will panic() if the image it has
3470 loaded does not have a signature.
3471 Defining this is useful when code which loads images
3472 in SPL cannot guarantee that absolutely all read errors
3474 An example is the LPC32XX MLC NAND driver, which will
3475 consider that a completely unreadable NAND block is bad,
3476 and thus should be skipped silently.
3478 CONFIG_SPL_ABORT_ON_RAW_IMAGE
3479 When defined, SPL will proceed to another boot method
3480 if the image it has loaded does not have a signature.
3482 CONFIG_SPL_RELOC_STACK
3483 Adress of the start of the stack SPL will use after
3484 relocation. If unspecified, this is equal to
3487 CONFIG_SYS_SPL_MALLOC_START
3488 Starting address of the malloc pool used in SPL.
3489 When this option is set the full malloc is used in SPL and
3490 it is set up by spl_init() and before that, the simple malloc()
3491 can be used if CONFIG_SYS_MALLOC_F is defined.
3493 CONFIG_SYS_SPL_MALLOC_SIZE
3494 The size of the malloc pool used in SPL.
3496 CONFIG_SPL_FRAMEWORK
3497 Enable the SPL framework under common/. This framework
3498 supports MMC, NAND and YMODEM loading of U-Boot and NAND
3499 NAND loading of the Linux Kernel.
3502 Enable booting directly to an OS from SPL.
3503 See also: doc/README.falcon
3505 CONFIG_SPL_DISPLAY_PRINT
3506 For ARM, enable an optional function to print more information
3507 about the running system.
3509 CONFIG_SPL_INIT_MINIMAL
3510 Arch init code should be built for a very small image
3512 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR,
3513 CONFIG_SYS_U_BOOT_MAX_SIZE_SECTORS,
3514 Address and partition on the MMC to load U-Boot from
3515 when the MMC is being used in raw mode.
3517 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_PARTITION
3518 Partition on the MMC to load U-Boot from when the MMC is being
3521 CONFIG_SYS_MMCSD_RAW_MODE_KERNEL_SECTOR
3522 Sector to load kernel uImage from when MMC is being
3523 used in raw mode (for Falcon mode)
3525 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTOR,
3526 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTORS
3527 Sector and number of sectors to load kernel argument
3528 parameters from when MMC is being used in raw mode
3531 CONFIG_SYS_MMCSD_FS_BOOT_PARTITION
3532 Partition on the MMC to load U-Boot from when the MMC is being
3535 CONFIG_SPL_FS_LOAD_PAYLOAD_NAME
3536 Filename to read to load U-Boot when reading from filesystem
3538 CONFIG_SPL_FS_LOAD_KERNEL_NAME
3539 Filename to read to load kernel uImage when reading
3540 from filesystem (for Falcon mode)
3542 CONFIG_SPL_FS_LOAD_ARGS_NAME
3543 Filename to read to load kernel argument parameters
3544 when reading from filesystem (for Falcon mode)
3546 CONFIG_SPL_MPC83XX_WAIT_FOR_NAND
3547 Set this for NAND SPL on PPC mpc83xx targets, so that
3548 start.S waits for the rest of the SPL to load before
3549 continuing (the hardware starts execution after just
3550 loading the first page rather than the full 4K).
3552 CONFIG_SPL_SKIP_RELOCATE
3553 Avoid SPL relocation
3555 CONFIG_SPL_NAND_BASE
3556 Include nand_base.c in the SPL. Requires
3557 CONFIG_SPL_NAND_DRIVERS.
3559 CONFIG_SPL_NAND_DRIVERS
3560 SPL uses normal NAND drivers, not minimal drivers.
3563 Include standard software ECC in the SPL
3565 CONFIG_SPL_NAND_SIMPLE
3566 Support for NAND boot using simple NAND drivers that
3567 expose the cmd_ctrl() interface.
3570 Support for a lightweight UBI (fastmap) scanner and
3573 CONFIG_SPL_NAND_RAW_ONLY
3574 Support to boot only raw u-boot.bin images. Use this only
3575 if you need to save space.
3577 CONFIG_SPL_COMMON_INIT_DDR
3578 Set for common ddr init with serial presence detect in
3581 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
3582 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
3583 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
3584 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
3585 CONFIG_SYS_NAND_ECCBYTES
3586 Defines the size and behavior of the NAND that SPL uses
3589 CONFIG_SPL_NAND_BOOT
3590 Add support NAND boot
3592 CONFIG_SYS_NAND_U_BOOT_OFFS
3593 Location in NAND to read U-Boot from
3595 CONFIG_SYS_NAND_U_BOOT_DST
3596 Location in memory to load U-Boot to
3598 CONFIG_SYS_NAND_U_BOOT_SIZE
3599 Size of image to load
3601 CONFIG_SYS_NAND_U_BOOT_START
3602 Entry point in loaded image to jump to
3604 CONFIG_SYS_NAND_HW_ECC_OOBFIRST
3605 Define this if you need to first read the OOB and then the
3606 data. This is used, for example, on davinci platforms.
3608 CONFIG_SPL_OMAP3_ID_NAND
3609 Support for an OMAP3-specific set of functions to return the
3610 ID and MFR of the first attached NAND chip, if present.
3612 CONFIG_SPL_RAM_DEVICE
3613 Support for running image already present in ram, in SPL binary
3616 Image offset to which the SPL should be padded before appending
3617 the SPL payload. By default, this is defined as
3618 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3619 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3620 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3623 Final target image containing SPL and payload. Some SPLs
3624 use an arch-specific makefile fragment instead, for
3625 example if more than one image needs to be produced.
3627 CONFIG_FIT_SPL_PRINT
3628 Printing information about a FIT image adds quite a bit of
3629 code to SPL. So this is normally disabled in SPL. Use this
3630 option to re-enable it. This will affect the output of the
3631 bootm command when booting a FIT image.
3635 Enable building of TPL globally.
3638 Image offset to which the TPL should be padded before appending
3639 the TPL payload. By default, this is defined as
3640 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3641 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3642 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3644 - Interrupt support (PPC):
3646 There are common interrupt_init() and timer_interrupt()
3647 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
3648 for CPU specific initialization. interrupt_init_cpu()
3649 should set decrementer_count to appropriate value. If
3650 CPU resets decrementer automatically after interrupt
3651 (ppc4xx) it should set decrementer_count to zero.
3652 timer_interrupt() calls timer_interrupt_cpu() for CPU
3653 specific handling. If board has watchdog / status_led
3654 / other_activity_monitor it works automatically from
3655 general timer_interrupt().
3658 Board initialization settings:
3659 ------------------------------
3661 During Initialization u-boot calls a number of board specific functions
3662 to allow the preparation of board specific prerequisites, e.g. pin setup
3663 before drivers are initialized. To enable these callbacks the
3664 following configuration macros have to be defined. Currently this is
3665 architecture specific, so please check arch/your_architecture/lib/board.c
3666 typically in board_init_f() and board_init_r().
3668 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
3669 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
3670 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
3671 - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
3673 Configuration Settings:
3674 -----------------------
3676 - CONFIG_SYS_SUPPORT_64BIT_DATA: Defined automatically if compiled as 64-bit.
3677 Optionally it can be defined to support 64-bit memory commands.
3679 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
3680 undefine this when you're short of memory.
3682 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
3683 width of the commands listed in the 'help' command output.
3685 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
3686 prompt for user input.
3688 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
3690 - CONFIG_SYS_PBSIZE: Buffer size for Console output
3692 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
3694 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
3695 the application (usually a Linux kernel) when it is
3698 - CONFIG_SYS_BAUDRATE_TABLE:
3699 List of legal baudrate settings for this board.
3701 - CONFIG_SYS_CONSOLE_INFO_QUIET
3702 Suppress display of console information at boot.
3704 - CONFIG_SYS_CONSOLE_IS_IN_ENV
3705 If the board specific function
3706 extern int overwrite_console (void);
3707 returns 1, the stdin, stderr and stdout are switched to the
3708 serial port, else the settings in the environment are used.
3710 - CONFIG_SYS_CONSOLE_OVERWRITE_ROUTINE
3711 Enable the call to overwrite_console().
3713 - CONFIG_SYS_CONSOLE_ENV_OVERWRITE
3714 Enable overwrite of previous console environment settings.
3716 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
3717 Begin and End addresses of the area used by the
3720 - CONFIG_SYS_ALT_MEMTEST:
3721 Enable an alternate, more extensive memory test.
3723 - CONFIG_SYS_MEMTEST_SCRATCH:
3724 Scratch address used by the alternate memory test
3725 You only need to set this if address zero isn't writeable
3727 - CONFIG_SYS_MEM_RESERVE_SECURE
3728 Only implemented for ARMv8 for now.
3729 If defined, the size of CONFIG_SYS_MEM_RESERVE_SECURE memory
3730 is substracted from total RAM and won't be reported to OS.
3731 This memory can be used as secure memory. A variable
3732 gd->arch.secure_ram is used to track the location. In systems
3733 the RAM base is not zero, or RAM is divided into banks,
3734 this variable needs to be recalcuated to get the address.
3736 - CONFIG_SYS_MEM_TOP_HIDE:
3737 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
3738 this specified memory area will get subtracted from the top
3739 (end) of RAM and won't get "touched" at all by U-Boot. By
3740 fixing up gd->ram_size the Linux kernel should gets passed
3741 the now "corrected" memory size and won't touch it either.
3742 This should work for arch/ppc and arch/powerpc. Only Linux
3743 board ports in arch/powerpc with bootwrapper support that
3744 recalculate the memory size from the SDRAM controller setup
3745 will have to get fixed in Linux additionally.
3747 This option can be used as a workaround for the 440EPx/GRx
3748 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
3751 WARNING: Please make sure that this value is a multiple of
3752 the Linux page size (normally 4k). If this is not the case,
3753 then the end address of the Linux memory will be located at a
3754 non page size aligned address and this could cause major
3757 - CONFIG_SYS_LOADS_BAUD_CHANGE:
3758 Enable temporary baudrate change while serial download
3760 - CONFIG_SYS_SDRAM_BASE:
3761 Physical start address of SDRAM. _Must_ be 0 here.
3763 - CONFIG_SYS_MBIO_BASE:
3764 Physical start address of Motherboard I/O (if using a
3767 - CONFIG_SYS_FLASH_BASE:
3768 Physical start address of Flash memory.
3770 - CONFIG_SYS_MONITOR_BASE:
3771 Physical start address of boot monitor code (set by
3772 make config files to be same as the text base address
3773 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
3774 CONFIG_SYS_FLASH_BASE when booting from flash.
3776 - CONFIG_SYS_MONITOR_LEN:
3777 Size of memory reserved for monitor code, used to
3778 determine _at_compile_time_ (!) if the environment is
3779 embedded within the U-Boot image, or in a separate
3782 - CONFIG_SYS_MALLOC_LEN:
3783 Size of DRAM reserved for malloc() use.
3785 - CONFIG_SYS_MALLOC_F_LEN
3786 Size of the malloc() pool for use before relocation. If
3787 this is defined, then a very simple malloc() implementation
3788 will become available before relocation. The address is just
3789 below the global data, and the stack is moved down to make
3792 This feature allocates regions with increasing addresses
3793 within the region. calloc() is supported, but realloc()
3794 is not available. free() is supported but does nothing.
3795 The memory will be freed (or in fact just forgotten) when
3796 U-Boot relocates itself.
3798 - CONFIG_SYS_MALLOC_SIMPLE
3799 Provides a simple and small malloc() and calloc() for those
3800 boards which do not use the full malloc in SPL (which is
3801 enabled with CONFIG_SYS_SPL_MALLOC_START).
3803 - CONFIG_SYS_NONCACHED_MEMORY:
3804 Size of non-cached memory area. This area of memory will be
3805 typically located right below the malloc() area and mapped
3806 uncached in the MMU. This is useful for drivers that would
3807 otherwise require a lot of explicit cache maintenance. For
3808 some drivers it's also impossible to properly maintain the
3809 cache. For example if the regions that need to be flushed
3810 are not a multiple of the cache-line size, *and* padding
3811 cannot be allocated between the regions to align them (i.e.
3812 if the HW requires a contiguous array of regions, and the
3813 size of each region is not cache-aligned), then a flush of
3814 one region may result in overwriting data that hardware has
3815 written to another region in the same cache-line. This can
3816 happen for example in network drivers where descriptors for
3817 buffers are typically smaller than the CPU cache-line (e.g.
3818 16 bytes vs. 32 or 64 bytes).
3820 Non-cached memory is only supported on 32-bit ARM at present.
3822 - CONFIG_SYS_BOOTM_LEN:
3823 Normally compressed uImages are limited to an
3824 uncompressed size of 8 MBytes. If this is not enough,
3825 you can define CONFIG_SYS_BOOTM_LEN in your board config file
3826 to adjust this setting to your needs.
3828 - CONFIG_SYS_BOOTMAPSZ:
3829 Maximum size of memory mapped by the startup code of
3830 the Linux kernel; all data that must be processed by
3831 the Linux kernel (bd_info, boot arguments, FDT blob if
3832 used) must be put below this limit, unless "bootm_low"
3833 environment variable is defined and non-zero. In such case
3834 all data for the Linux kernel must be between "bootm_low"
3835 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
3836 variable "bootm_mapsize" will override the value of
3837 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
3838 then the value in "bootm_size" will be used instead.
3840 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
3841 Enable initrd_high functionality. If defined then the
3842 initrd_high feature is enabled and the bootm ramdisk subcommand
3845 - CONFIG_SYS_BOOT_GET_CMDLINE:
3846 Enables allocating and saving kernel cmdline in space between
3847 "bootm_low" and "bootm_low" + BOOTMAPSZ.
3849 - CONFIG_SYS_BOOT_GET_KBD:
3850 Enables allocating and saving a kernel copy of the bd_info in
3851 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
3853 - CONFIG_SYS_MAX_FLASH_BANKS:
3854 Max number of Flash memory banks
3856 - CONFIG_SYS_MAX_FLASH_SECT:
3857 Max number of sectors on a Flash chip
3859 - CONFIG_SYS_FLASH_ERASE_TOUT:
3860 Timeout for Flash erase operations (in ms)
3862 - CONFIG_SYS_FLASH_WRITE_TOUT:
3863 Timeout for Flash write operations (in ms)
3865 - CONFIG_SYS_FLASH_LOCK_TOUT
3866 Timeout for Flash set sector lock bit operation (in ms)
3868 - CONFIG_SYS_FLASH_UNLOCK_TOUT
3869 Timeout for Flash clear lock bits operation (in ms)
3871 - CONFIG_SYS_FLASH_PROTECTION
3872 If defined, hardware flash sectors protection is used
3873 instead of U-Boot software protection.
3875 - CONFIG_SYS_DIRECT_FLASH_TFTP:
3877 Enable TFTP transfers directly to flash memory;
3878 without this option such a download has to be
3879 performed in two steps: (1) download to RAM, and (2)
3880 copy from RAM to flash.
3882 The two-step approach is usually more reliable, since
3883 you can check if the download worked before you erase
3884 the flash, but in some situations (when system RAM is
3885 too limited to allow for a temporary copy of the
3886 downloaded image) this option may be very useful.
3888 - CONFIG_SYS_FLASH_CFI:
3889 Define if the flash driver uses extra elements in the
3890 common flash structure for storing flash geometry.
3892 - CONFIG_FLASH_CFI_DRIVER
3893 This option also enables the building of the cfi_flash driver
3894 in the drivers directory
3896 - CONFIG_FLASH_CFI_MTD
3897 This option enables the building of the cfi_mtd driver
3898 in the drivers directory. The driver exports CFI flash
3901 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
3902 Use buffered writes to flash.
3904 - CONFIG_FLASH_SPANSION_S29WS_N
3905 s29ws-n MirrorBit flash has non-standard addresses for buffered
3908 - CONFIG_SYS_FLASH_QUIET_TEST
3909 If this option is defined, the common CFI flash doesn't
3910 print it's warning upon not recognized FLASH banks. This
3911 is useful, if some of the configured banks are only
3912 optionally available.
3914 - CONFIG_FLASH_SHOW_PROGRESS
3915 If defined (must be an integer), print out countdown
3916 digits and dots. Recommended value: 45 (9..1) for 80
3917 column displays, 15 (3..1) for 40 column displays.
3919 - CONFIG_FLASH_VERIFY
3920 If defined, the content of the flash (destination) is compared
3921 against the source after the write operation. An error message
3922 will be printed when the contents are not identical.
3923 Please note that this option is useless in nearly all cases,
3924 since such flash programming errors usually are detected earlier
3925 while unprotecting/erasing/programming. Please only enable
3926 this option if you really know what you are doing.
3928 - CONFIG_SYS_RX_ETH_BUFFER:
3929 Defines the number of Ethernet receive buffers. On some
3930 Ethernet controllers it is recommended to set this value
3931 to 8 or even higher (EEPRO100 or 405 EMAC), since all
3932 buffers can be full shortly after enabling the interface
3933 on high Ethernet traffic.
3934 Defaults to 4 if not defined.
3936 - CONFIG_ENV_MAX_ENTRIES
3938 Maximum number of entries in the hash table that is used
3939 internally to store the environment settings. The default
3940 setting is supposed to be generous and should work in most
3941 cases. This setting can be used to tune behaviour; see
3942 lib/hashtable.c for details.
3944 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3945 - CONFIG_ENV_FLAGS_LIST_STATIC
3946 Enable validation of the values given to environment variables when
3947 calling env set. Variables can be restricted to only decimal,
3948 hexadecimal, or boolean. If CONFIG_CMD_NET is also defined,
3949 the variables can also be restricted to IP address or MAC address.
3951 The format of the list is:
3952 type_attribute = [s|d|x|b|i|m]
3953 access_attribute = [a|r|o|c]
3954 attributes = type_attribute[access_attribute]
3955 entry = variable_name[:attributes]
3958 The type attributes are:
3959 s - String (default)
3962 b - Boolean ([1yYtT|0nNfF])
3966 The access attributes are:
3972 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3973 Define this to a list (string) to define the ".flags"
3974 environment variable in the default or embedded environment.
3976 - CONFIG_ENV_FLAGS_LIST_STATIC
3977 Define this to a list (string) to define validation that
3978 should be done if an entry is not found in the ".flags"
3979 environment variable. To override a setting in the static
3980 list, simply add an entry for the same variable name to the
3983 If CONFIG_REGEX is defined, the variable_name above is evaluated as a
3984 regular expression. This allows multiple variables to define the same
3985 flags without explicitly listing them for each variable.
3987 - CONFIG_ENV_ACCESS_IGNORE_FORCE
3988 If defined, don't allow the -f switch to env set override variable
3991 - CONFIG_OMAP_PLATFORM_RESET_TIME_MAX_USEC (OMAP only)
3992 This is set by OMAP boards for the max time that reset should
3993 be asserted. See doc/README.omap-reset-time for details on how
3994 the value can be calculated on a given board.
3997 If stdint.h is available with your toolchain you can define this
3998 option to enable it. You can provide option 'USE_STDINT=1' when
3999 building U-Boot to enable this.
4001 The following definitions that deal with the placement and management
4002 of environment data (variable area); in general, we support the
4003 following configurations:
4005 - CONFIG_BUILD_ENVCRC:
4007 Builds up envcrc with the target environment so that external utils
4008 may easily extract it and embed it in final U-Boot images.
4010 - CONFIG_ENV_IS_IN_FLASH:
4012 Define this if the environment is in flash memory.
4014 a) The environment occupies one whole flash sector, which is
4015 "embedded" in the text segment with the U-Boot code. This
4016 happens usually with "bottom boot sector" or "top boot
4017 sector" type flash chips, which have several smaller
4018 sectors at the start or the end. For instance, such a
4019 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
4020 such a case you would place the environment in one of the
4021 4 kB sectors - with U-Boot code before and after it. With
4022 "top boot sector" type flash chips, you would put the
4023 environment in one of the last sectors, leaving a gap
4024 between U-Boot and the environment.
4026 - CONFIG_ENV_OFFSET:
4028 Offset of environment data (variable area) to the
4029 beginning of flash memory; for instance, with bottom boot
4030 type flash chips the second sector can be used: the offset
4031 for this sector is given here.
4033 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
4037 This is just another way to specify the start address of
4038 the flash sector containing the environment (instead of
4041 - CONFIG_ENV_SECT_SIZE:
4043 Size of the sector containing the environment.
4046 b) Sometimes flash chips have few, equal sized, BIG sectors.
4047 In such a case you don't want to spend a whole sector for
4052 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
4053 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
4054 of this flash sector for the environment. This saves
4055 memory for the RAM copy of the environment.
4057 It may also save flash memory if you decide to use this
4058 when your environment is "embedded" within U-Boot code,
4059 since then the remainder of the flash sector could be used
4060 for U-Boot code. It should be pointed out that this is
4061 STRONGLY DISCOURAGED from a robustness point of view:
4062 updating the environment in flash makes it always
4063 necessary to erase the WHOLE sector. If something goes
4064 wrong before the contents has been restored from a copy in
4065 RAM, your target system will be dead.
4067 - CONFIG_ENV_ADDR_REDUND
4068 CONFIG_ENV_SIZE_REDUND
4070 These settings describe a second storage area used to hold
4071 a redundant copy of the environment data, so that there is
4072 a valid backup copy in case there is a power failure during
4073 a "saveenv" operation.
4075 BE CAREFUL! Any changes to the flash layout, and some changes to the
4076 source code will make it necessary to adapt <board>/u-boot.lds*
4080 - CONFIG_ENV_IS_IN_NVRAM:
4082 Define this if you have some non-volatile memory device
4083 (NVRAM, battery buffered SRAM) which you want to use for the
4089 These two #defines are used to determine the memory area you
4090 want to use for environment. It is assumed that this memory
4091 can just be read and written to, without any special
4094 BE CAREFUL! The first access to the environment happens quite early
4095 in U-Boot initialization (when we try to get the setting of for the
4096 console baudrate). You *MUST* have mapped your NVRAM area then, or
4099 Please note that even with NVRAM we still use a copy of the
4100 environment in RAM: we could work on NVRAM directly, but we want to
4101 keep settings there always unmodified except somebody uses "saveenv"
4102 to save the current settings.
4105 - CONFIG_ENV_IS_IN_EEPROM:
4107 Use this if you have an EEPROM or similar serial access
4108 device and a driver for it.
4110 - CONFIG_ENV_OFFSET:
4113 These two #defines specify the offset and size of the
4114 environment area within the total memory of your EEPROM.
4116 - CONFIG_SYS_I2C_EEPROM_ADDR:
4117 If defined, specified the chip address of the EEPROM device.
4118 The default address is zero.
4120 - CONFIG_SYS_I2C_EEPROM_BUS:
4121 If defined, specified the i2c bus of the EEPROM device.
4123 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
4124 If defined, the number of bits used to address bytes in a
4125 single page in the EEPROM device. A 64 byte page, for example
4126 would require six bits.
4128 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
4129 If defined, the number of milliseconds to delay between
4130 page writes. The default is zero milliseconds.
4132 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
4133 The length in bytes of the EEPROM memory array address. Note
4134 that this is NOT the chip address length!
4136 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
4137 EEPROM chips that implement "address overflow" are ones
4138 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
4139 address and the extra bits end up in the "chip address" bit
4140 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
4143 Note that we consider the length of the address field to
4144 still be one byte because the extra address bits are hidden
4145 in the chip address.
4147 - CONFIG_SYS_EEPROM_SIZE:
4148 The size in bytes of the EEPROM device.
4150 - CONFIG_ENV_EEPROM_IS_ON_I2C
4151 define this, if you have I2C and SPI activated, and your
4152 EEPROM, which holds the environment, is on the I2C bus.
4154 - CONFIG_I2C_ENV_EEPROM_BUS
4155 if you have an Environment on an EEPROM reached over
4156 I2C muxes, you can define here, how to reach this
4157 EEPROM. For example:
4159 #define CONFIG_I2C_ENV_EEPROM_BUS 1
4161 EEPROM which holds the environment, is reached over
4162 a pca9547 i2c mux with address 0x70, channel 3.
4164 - CONFIG_ENV_IS_IN_DATAFLASH:
4166 Define this if you have a DataFlash memory device which you
4167 want to use for the environment.
4169 - CONFIG_ENV_OFFSET:
4173 These three #defines specify the offset and size of the
4174 environment area within the total memory of your DataFlash placed
4175 at the specified address.
4177 - CONFIG_ENV_IS_IN_SPI_FLASH:
4179 Define this if you have a SPI Flash memory device which you
4180 want to use for the environment.
4182 - CONFIG_ENV_OFFSET:
4185 These two #defines specify the offset and size of the
4186 environment area within the SPI Flash. CONFIG_ENV_OFFSET must be
4187 aligned to an erase sector boundary.
4189 - CONFIG_ENV_SECT_SIZE:
4191 Define the SPI flash's sector size.
4193 - CONFIG_ENV_OFFSET_REDUND (optional):
4195 This setting describes a second storage area of CONFIG_ENV_SIZE
4196 size used to hold a redundant copy of the environment data, so
4197 that there is a valid backup copy in case there is a power failure
4198 during a "saveenv" operation. CONFIG_ENV_OFFSET_RENDUND must be
4199 aligned to an erase sector boundary.
4201 - CONFIG_ENV_SPI_BUS (optional):
4202 - CONFIG_ENV_SPI_CS (optional):
4204 Define the SPI bus and chip select. If not defined they will be 0.
4206 - CONFIG_ENV_SPI_MAX_HZ (optional):
4208 Define the SPI max work clock. If not defined then use 1MHz.
4210 - CONFIG_ENV_SPI_MODE (optional):
4212 Define the SPI work mode. If not defined then use SPI_MODE_3.
4214 - CONFIG_ENV_IS_IN_REMOTE:
4216 Define this if you have a remote memory space which you
4217 want to use for the local device's environment.
4222 These two #defines specify the address and size of the
4223 environment area within the remote memory space. The
4224 local device can get the environment from remote memory
4225 space by SRIO or PCIE links.
4227 BE CAREFUL! For some special cases, the local device can not use
4228 "saveenv" command. For example, the local device will get the
4229 environment stored in a remote NOR flash by SRIO or PCIE link,
4230 but it can not erase, write this NOR flash by SRIO or PCIE interface.
4232 - CONFIG_ENV_IS_IN_NAND:
4234 Define this if you have a NAND device which you want to use
4235 for the environment.
4237 - CONFIG_ENV_OFFSET:
4240 These two #defines specify the offset and size of the environment
4241 area within the first NAND device. CONFIG_ENV_OFFSET must be
4242 aligned to an erase block boundary.
4244 - CONFIG_ENV_OFFSET_REDUND (optional):
4246 This setting describes a second storage area of CONFIG_ENV_SIZE
4247 size used to hold a redundant copy of the environment data, so
4248 that there is a valid backup copy in case there is a power failure
4249 during a "saveenv" operation. CONFIG_ENV_OFFSET_RENDUND must be
4250 aligned to an erase block boundary.
4252 - CONFIG_ENV_RANGE (optional):
4254 Specifies the length of the region in which the environment
4255 can be written. This should be a multiple of the NAND device's
4256 block size. Specifying a range with more erase blocks than
4257 are needed to hold CONFIG_ENV_SIZE allows bad blocks within
4258 the range to be avoided.
4260 - CONFIG_ENV_OFFSET_OOB (optional):
4262 Enables support for dynamically retrieving the offset of the
4263 environment from block zero's out-of-band data. The
4264 "nand env.oob" command can be used to record this offset.
4265 Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
4266 using CONFIG_ENV_OFFSET_OOB.
4268 - CONFIG_NAND_ENV_DST
4270 Defines address in RAM to which the nand_spl code should copy the
4271 environment. If redundant environment is used, it will be copied to
4272 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
4274 - CONFIG_ENV_IS_IN_UBI:
4276 Define this if you have an UBI volume that you want to use for the
4277 environment. This has the benefit of wear-leveling the environment
4278 accesses, which is important on NAND.
4280 - CONFIG_ENV_UBI_PART:
4282 Define this to a string that is the mtd partition containing the UBI.
4284 - CONFIG_ENV_UBI_VOLUME:
4286 Define this to the name of the volume that you want to store the
4289 - CONFIG_ENV_UBI_VOLUME_REDUND:
4291 Define this to the name of another volume to store a second copy of
4292 the environment in. This will enable redundant environments in UBI.
4293 It is assumed that both volumes are in the same MTD partition.
4295 - CONFIG_UBI_SILENCE_MSG
4296 - CONFIG_UBIFS_SILENCE_MSG
4298 You will probably want to define these to avoid a really noisy system
4299 when storing the env in UBI.
4301 - CONFIG_ENV_IS_IN_FAT:
4302 Define this if you want to use the FAT file system for the environment.
4304 - FAT_ENV_INTERFACE:
4306 Define this to a string that is the name of the block device.
4308 - FAT_ENV_DEV_AND_PART:
4310 Define this to a string to specify the partition of the device. It can
4313 "D:P", "D:0", "D", "D:" or "D:auto" (D, P are integers. And P >= 1)
4314 - "D:P": device D partition P. Error occurs if device D has no
4317 - "D" or "D:": device D partition 1 if device D has partition
4318 table, or the whole device D if has no partition
4320 - "D:auto": first partition in device D with bootable flag set.
4321 If none, first valid partition in device D. If no
4322 partition table then means device D.
4326 It's a string of the FAT file name. This file use to store the
4330 This should be defined. Otherwise it cannot save the environment file.
4332 - CONFIG_ENV_IS_IN_MMC:
4334 Define this if you have an MMC device which you want to use for the
4337 - CONFIG_SYS_MMC_ENV_DEV:
4339 Specifies which MMC device the environment is stored in.
4341 - CONFIG_SYS_MMC_ENV_PART (optional):
4343 Specifies which MMC partition the environment is stored in. If not
4344 set, defaults to partition 0, the user area. Common values might be
4345 1 (first MMC boot partition), 2 (second MMC boot partition).
4347 - CONFIG_ENV_OFFSET:
4350 These two #defines specify the offset and size of the environment
4351 area within the specified MMC device.
4353 If offset is positive (the usual case), it is treated as relative to
4354 the start of the MMC partition. If offset is negative, it is treated
4355 as relative to the end of the MMC partition. This can be useful if
4356 your board may be fitted with different MMC devices, which have
4357 different sizes for the MMC partitions, and you always want the
4358 environment placed at the very end of the partition, to leave the
4359 maximum possible space before it, to store other data.
4361 These two values are in units of bytes, but must be aligned to an
4362 MMC sector boundary.
4364 - CONFIG_ENV_OFFSET_REDUND (optional):
4366 Specifies a second storage area, of CONFIG_ENV_SIZE size, used to
4367 hold a redundant copy of the environment data. This provides a
4368 valid backup copy in case the other copy is corrupted, e.g. due
4369 to a power failure during a "saveenv" operation.
4371 This value may also be positive or negative; this is handled in the
4372 same way as CONFIG_ENV_OFFSET.
4374 This value is also in units of bytes, but must also be aligned to
4375 an MMC sector boundary.
4377 - CONFIG_ENV_SIZE_REDUND (optional):
4379 This value need not be set, even when CONFIG_ENV_OFFSET_REDUND is
4380 set. If this value is set, it must be set to the same value as
4383 - CONFIG_SYS_SPI_INIT_OFFSET
4385 Defines offset to the initial SPI buffer area in DPRAM. The
4386 area is used at an early stage (ROM part) if the environment
4387 is configured to reside in the SPI EEPROM: We need a 520 byte
4388 scratch DPRAM area. It is used between the two initialization
4389 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
4390 to be a good choice since it makes it far enough from the
4391 start of the data area as well as from the stack pointer.
4393 Please note that the environment is read-only until the monitor
4394 has been relocated to RAM and a RAM copy of the environment has been
4395 created; also, when using EEPROM you will have to use getenv_f()
4396 until then to read environment variables.
4398 The environment is protected by a CRC32 checksum. Before the monitor
4399 is relocated into RAM, as a result of a bad CRC you will be working
4400 with the compiled-in default environment - *silently*!!! [This is
4401 necessary, because the first environment variable we need is the
4402 "baudrate" setting for the console - if we have a bad CRC, we don't
4403 have any device yet where we could complain.]
4405 Note: once the monitor has been relocated, then it will complain if
4406 the default environment is used; a new CRC is computed as soon as you
4407 use the "saveenv" command to store a valid environment.
4409 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
4410 Echo the inverted Ethernet link state to the fault LED.
4412 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
4413 also needs to be defined.
4415 - CONFIG_SYS_FAULT_MII_ADDR:
4416 MII address of the PHY to check for the Ethernet link state.
4418 - CONFIG_NS16550_MIN_FUNCTIONS:
4419 Define this if you desire to only have use of the NS16550_init
4420 and NS16550_putc functions for the serial driver located at
4421 drivers/serial/ns16550.c. This option is useful for saving
4422 space for already greatly restricted images, including but not
4423 limited to NAND_SPL configurations.
4425 - CONFIG_DISPLAY_BOARDINFO
4426 Display information about the board that U-Boot is running on
4427 when U-Boot starts up. The board function checkboard() is called
4430 - CONFIG_DISPLAY_BOARDINFO_LATE
4431 Similar to the previous option, but display this information
4432 later, once stdio is running and output goes to the LCD, if
4435 - CONFIG_BOARD_SIZE_LIMIT:
4436 Maximum size of the U-Boot image. When defined, the
4437 build system checks that the actual size does not
4440 Low Level (hardware related) configuration options:
4441 ---------------------------------------------------
4443 - CONFIG_SYS_CACHELINE_SIZE:
4444 Cache Line Size of the CPU.
4446 - CONFIG_SYS_DEFAULT_IMMR:
4447 Default address of the IMMR after system reset.
4449 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
4450 and RPXsuper) to be able to adjust the position of
4451 the IMMR register after a reset.
4453 - CONFIG_SYS_CCSRBAR_DEFAULT:
4454 Default (power-on reset) physical address of CCSR on Freescale
4457 - CONFIG_SYS_CCSRBAR:
4458 Virtual address of CCSR. On a 32-bit build, this is typically
4459 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
4461 CONFIG_SYS_DEFAULT_IMMR must also be set to this value,
4462 for cross-platform code that uses that macro instead.
4464 - CONFIG_SYS_CCSRBAR_PHYS:
4465 Physical address of CCSR. CCSR can be relocated to a new
4466 physical address, if desired. In this case, this macro should
4467 be set to that address. Otherwise, it should be set to the
4468 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
4469 is typically relocated on 36-bit builds. It is recommended
4470 that this macro be defined via the _HIGH and _LOW macros:
4472 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
4473 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
4475 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
4476 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
4477 either 0 (32-bit build) or 0xF (36-bit build). This macro is
4478 used in assembly code, so it must not contain typecasts or
4479 integer size suffixes (e.g. "ULL").
4481 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
4482 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
4483 used in assembly code, so it must not contain typecasts or
4484 integer size suffixes (e.g. "ULL").
4486 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
4487 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
4488 forced to a value that ensures that CCSR is not relocated.
4490 - Floppy Disk Support:
4491 CONFIG_SYS_FDC_DRIVE_NUMBER
4493 the default drive number (default value 0)
4495 CONFIG_SYS_ISA_IO_STRIDE
4497 defines the spacing between FDC chipset registers
4500 CONFIG_SYS_ISA_IO_OFFSET
4502 defines the offset of register from address. It
4503 depends on which part of the data bus is connected to
4504 the FDC chipset. (default value 0)
4506 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
4507 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
4510 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
4511 fdc_hw_init() is called at the beginning of the FDC
4512 setup. fdc_hw_init() must be provided by the board
4513 source code. It is used to make hardware-dependent
4517 Most IDE controllers were designed to be connected with PCI
4518 interface. Only few of them were designed for AHB interface.
4519 When software is doing ATA command and data transfer to
4520 IDE devices through IDE-AHB controller, some additional
4521 registers accessing to these kind of IDE-AHB controller
4524 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
4525 DO NOT CHANGE unless you know exactly what you're
4526 doing! (11-4) [MPC8xx/82xx systems only]
4528 - CONFIG_SYS_INIT_RAM_ADDR:
4530 Start address of memory area that can be used for
4531 initial data and stack; please note that this must be
4532 writable memory that is working WITHOUT special
4533 initialization, i. e. you CANNOT use normal RAM which
4534 will become available only after programming the
4535 memory controller and running certain initialization
4538 U-Boot uses the following memory types:
4539 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
4540 - MPC824X: data cache
4541 - PPC4xx: data cache
4543 - CONFIG_SYS_GBL_DATA_OFFSET:
4545 Offset of the initial data structure in the memory
4546 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
4547 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
4548 data is located at the end of the available space
4549 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
4550 CONFIG_SYS_INIT_DATA_SIZE), and the initial stack is just
4551 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
4552 CONFIG_SYS_GBL_DATA_OFFSET) downward.
4555 On the MPC824X (or other systems that use the data
4556 cache for initial memory) the address chosen for
4557 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
4558 point to an otherwise UNUSED address space between
4559 the top of RAM and the start of the PCI space.
4561 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
4563 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
4565 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
4567 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
4569 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
4571 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
4573 - CONFIG_SYS_OR_TIMING_SDRAM:
4576 - CONFIG_SYS_MAMR_PTA:
4577 periodic timer for refresh
4579 - CONFIG_SYS_DER: Debug Event Register (37-47)
4581 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
4582 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
4583 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
4584 CONFIG_SYS_BR1_PRELIM:
4585 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
4587 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
4588 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
4589 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
4590 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
4592 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
4593 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
4594 Machine Mode Register and Memory Periodic Timer
4595 Prescaler definitions (SDRAM timing)
4597 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
4598 enable I2C microcode relocation patch (MPC8xx);
4599 define relocation offset in DPRAM [DSP2]
4601 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
4602 enable SMC microcode relocation patch (MPC8xx);
4603 define relocation offset in DPRAM [SMC1]
4605 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
4606 enable SPI microcode relocation patch (MPC8xx);
4607 define relocation offset in DPRAM [SCC4]
4609 - CONFIG_SYS_USE_OSCCLK:
4610 Use OSCM clock mode on MBX8xx board. Be careful,
4611 wrong setting might damage your board. Read
4612 doc/README.MBX before setting this variable!
4614 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
4615 Offset of the bootmode word in DPRAM used by post
4616 (Power On Self Tests). This definition overrides
4617 #define'd default value in commproc.h resp.
4620 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
4621 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
4622 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
4623 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
4624 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
4625 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
4626 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
4627 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
4628 Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
4630 - CONFIG_PCI_DISABLE_PCIE:
4631 Disable PCI-Express on systems where it is supported but not
4634 - CONFIG_PCI_ENUM_ONLY
4635 Only scan through and get the devices on the buses.
4636 Don't do any setup work, presumably because someone or
4637 something has already done it, and we don't need to do it
4638 a second time. Useful for platforms that are pre-booted
4639 by coreboot or similar.
4641 - CONFIG_PCI_INDIRECT_BRIDGE:
4642 Enable support for indirect PCI bridges.
4645 Chip has SRIO or not
4648 Board has SRIO 1 port available
4651 Board has SRIO 2 port available
4653 - CONFIG_SRIO_PCIE_BOOT_MASTER
4654 Board can support master function for Boot from SRIO and PCIE
4656 - CONFIG_SYS_SRIOn_MEM_VIRT:
4657 Virtual Address of SRIO port 'n' memory region
4659 - CONFIG_SYS_SRIOn_MEM_PHYS:
4660 Physical Address of SRIO port 'n' memory region
4662 - CONFIG_SYS_SRIOn_MEM_SIZE:
4663 Size of SRIO port 'n' memory region
4665 - CONFIG_SYS_NAND_BUSWIDTH_16BIT
4666 Defined to tell the NAND controller that the NAND chip is using
4668 Not all NAND drivers use this symbol.
4669 Example of drivers that use it:
4670 - drivers/mtd/nand/ndfc.c
4671 - drivers/mtd/nand/mxc_nand.c
4673 - CONFIG_SYS_NDFC_EBC0_CFG
4674 Sets the EBC0_CFG register for the NDFC. If not defined
4675 a default value will be used.
4678 Get DDR timing information from an I2C EEPROM. Common
4679 with pluggable memory modules such as SODIMMs
4682 I2C address of the SPD EEPROM
4684 - CONFIG_SYS_SPD_BUS_NUM
4685 If SPD EEPROM is on an I2C bus other than the first
4686 one, specify here. Note that the value must resolve
4687 to something your driver can deal with.
4689 - CONFIG_SYS_DDR_RAW_TIMING
4690 Get DDR timing information from other than SPD. Common with
4691 soldered DDR chips onboard without SPD. DDR raw timing
4692 parameters are extracted from datasheet and hard-coded into
4693 header files or board specific files.
4695 - CONFIG_FSL_DDR_INTERACTIVE
4696 Enable interactive DDR debugging. See doc/README.fsl-ddr.
4698 - CONFIG_FSL_DDR_SYNC_REFRESH
4699 Enable sync of refresh for multiple controllers.
4701 - CONFIG_FSL_DDR_BIST
4702 Enable built-in memory test for Freescale DDR controllers.
4704 - CONFIG_SYS_83XX_DDR_USES_CS0
4705 Only for 83xx systems. If specified, then DDR should
4706 be configured using CS0 and CS1 instead of CS2 and CS3.
4708 - CONFIG_ETHER_ON_FEC[12]
4709 Define to enable FEC[12] on a 8xx series processor.
4711 - CONFIG_FEC[12]_PHY
4712 Define to the hardcoded PHY address which corresponds
4713 to the given FEC; i. e.
4714 #define CONFIG_FEC1_PHY 4
4715 means that the PHY with address 4 is connected to FEC1
4717 When set to -1, means to probe for first available.
4719 - CONFIG_FEC[12]_PHY_NORXERR
4720 The PHY does not have a RXERR line (RMII only).
4721 (so program the FEC to ignore it).
4724 Enable RMII mode for all FECs.
4725 Note that this is a global option, we can't
4726 have one FEC in standard MII mode and another in RMII mode.
4728 - CONFIG_CRC32_VERIFY
4729 Add a verify option to the crc32 command.
4732 => crc32 -v <address> <count> <crc32>
4734 Where address/count indicate a memory area
4735 and crc32 is the correct crc32 which the
4739 Add the "loopw" memory command. This only takes effect if
4740 the memory commands are activated globally (CONFIG_CMD_MEM).
4743 Add the "mdc" and "mwc" memory commands. These are cyclic
4748 This command will print 4 bytes (10,11,12,13) each 500 ms.
4750 => mwc.l 100 12345678 10
4751 This command will write 12345678 to address 100 all 10 ms.
4753 This only takes effect if the memory commands are activated
4754 globally (CONFIG_CMD_MEM).
4756 - CONFIG_SKIP_LOWLEVEL_INIT
4757 [ARM, NDS32, MIPS only] If this variable is defined, then certain
4758 low level initializations (like setting up the memory
4759 controller) are omitted and/or U-Boot does not
4760 relocate itself into RAM.
4762 Normally this variable MUST NOT be defined. The only
4763 exception is when U-Boot is loaded (to RAM) by some
4764 other boot loader or by a debugger which performs
4765 these initializations itself.
4767 - CONFIG_SKIP_LOWLEVEL_INIT_ONLY
4768 [ARM926EJ-S only] This allows just the call to lowlevel_init()
4769 to be skipped. The normal CP15 init (such as enabling the
4770 instruction cache) is still performed.
4773 Modifies the behaviour of start.S when compiling a loader
4774 that is executed before the actual U-Boot. E.g. when
4775 compiling a NAND SPL.
4778 Modifies the behaviour of start.S when compiling a loader
4779 that is executed after the SPL and before the actual U-Boot.
4780 It is loaded by the SPL.
4782 - CONFIG_SYS_MPC85XX_NO_RESETVEC
4783 Only for 85xx systems. If this variable is specified, the section
4784 .resetvec is not kept and the section .bootpg is placed in the
4785 previous 4k of the .text section.
4787 - CONFIG_ARCH_MAP_SYSMEM
4788 Generally U-Boot (and in particular the md command) uses
4789 effective address. It is therefore not necessary to regard
4790 U-Boot address as virtual addresses that need to be translated
4791 to physical addresses. However, sandbox requires this, since
4792 it maintains its own little RAM buffer which contains all
4793 addressable memory. This option causes some memory accesses
4794 to be mapped through map_sysmem() / unmap_sysmem().
4796 - CONFIG_USE_ARCH_MEMCPY
4797 CONFIG_USE_ARCH_MEMSET
4798 If these options are used a optimized version of memcpy/memset will
4799 be used if available. These functions may be faster under some
4800 conditions but may increase the binary size.
4802 - CONFIG_X86_RESET_VECTOR
4803 If defined, the x86 reset vector code is included. This is not
4804 needed when U-Boot is running from Coreboot.
4807 Defines the MPU clock speed (in MHz).
4809 NOTE : currently only supported on AM335x platforms.
4811 - CONFIG_SPL_AM33XX_ENABLE_RTC32K_OSC:
4812 Enables the RTC32K OSC on AM33xx based plattforms
4814 - CONFIG_SYS_NAND_NO_SUBPAGE_WRITE
4815 Option to disable subpage write in NAND driver
4816 driver that uses this:
4817 drivers/mtd/nand/davinci_nand.c
4819 Freescale QE/FMAN Firmware Support:
4820 -----------------------------------
4822 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
4823 loading of "firmware", which is encoded in the QE firmware binary format.
4824 This firmware often needs to be loaded during U-Boot booting, so macros
4825 are used to identify the storage device (NOR flash, SPI, etc) and the address
4828 - CONFIG_SYS_FMAN_FW_ADDR
4829 The address in the storage device where the FMAN microcode is located. The
4830 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4833 - CONFIG_SYS_QE_FW_ADDR
4834 The address in the storage device where the QE microcode is located. The
4835 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4838 - CONFIG_SYS_QE_FMAN_FW_LENGTH
4839 The maximum possible size of the firmware. The firmware binary format
4840 has a field that specifies the actual size of the firmware, but it
4841 might not be possible to read any part of the firmware unless some
4842 local storage is allocated to hold the entire firmware first.
4844 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
4845 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
4846 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
4847 virtual address in NOR flash.
4849 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
4850 Specifies that QE/FMAN firmware is located in NAND flash.
4851 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
4853 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
4854 Specifies that QE/FMAN firmware is located on the primary SD/MMC
4855 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
4857 - CONFIG_SYS_QE_FMAN_FW_IN_SPIFLASH
4858 Specifies that QE/FMAN firmware is located on the primary SPI
4859 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
4861 - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
4862 Specifies that QE/FMAN firmware is located in the remote (master)
4863 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
4864 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
4865 window->master inbound window->master LAW->the ucode address in
4866 master's memory space.
4868 Freescale Layerscape Management Complex Firmware Support:
4869 ---------------------------------------------------------
4870 The Freescale Layerscape Management Complex (MC) supports the loading of
4872 This firmware often needs to be loaded during U-Boot booting, so macros
4873 are used to identify the storage device (NOR flash, SPI, etc) and the address
4876 - CONFIG_FSL_MC_ENET
4877 Enable the MC driver for Layerscape SoCs.
4879 - CONFIG_SYS_LS_MC_FW_ADDR
4880 The address in the storage device where the firmware is located. The
4881 meaning of this address depends on which CONFIG_SYS_LS_MC_FW_IN_xxx macro
4884 - CONFIG_SYS_LS_MC_FW_LENGTH
4885 The maximum possible size of the firmware. The firmware binary format
4886 has a field that specifies the actual size of the firmware, but it
4887 might not be possible to read any part of the firmware unless some
4888 local storage is allocated to hold the entire firmware first.
4890 - CONFIG_SYS_LS_MC_FW_IN_NOR
4891 Specifies that MC firmware is located in NOR flash, mapped as
4892 normal addressable memory via the LBC. CONFIG_SYS_LS_MC_FW_ADDR is the
4893 virtual address in NOR flash.
4895 Freescale Layerscape Debug Server Support:
4896 -------------------------------------------
4897 The Freescale Layerscape Debug Server Support supports the loading of
4898 "Debug Server firmware" and triggering SP boot-rom.
4899 This firmware often needs to be loaded during U-Boot booting.
4901 - CONFIG_SYS_MC_RSV_MEM_ALIGN
4902 Define alignment of reserved memory MC requires
4907 In order to achieve reproducible builds, timestamps used in the U-Boot build
4908 process have to be set to a fixed value.
4910 This is done using the SOURCE_DATE_EPOCH environment variable.
4911 SOURCE_DATE_EPOCH is to be set on the build host's shell, not as a configuration
4912 option for U-Boot or an environment variable in U-Boot.
4914 SOURCE_DATE_EPOCH should be set to a number of seconds since the epoch, in UTC.
4916 Building the Software:
4917 ======================
4919 Building U-Boot has been tested in several native build environments
4920 and in many different cross environments. Of course we cannot support
4921 all possibly existing versions of cross development tools in all
4922 (potentially obsolete) versions. In case of tool chain problems we
4923 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
4924 which is extensively used to build and test U-Boot.
4926 If you are not using a native environment, it is assumed that you
4927 have GNU cross compiling tools available in your path. In this case,
4928 you must set the environment variable CROSS_COMPILE in your shell.
4929 Note that no changes to the Makefile or any other source files are
4930 necessary. For example using the ELDK on a 4xx CPU, please enter:
4932 $ CROSS_COMPILE=ppc_4xx-
4933 $ export CROSS_COMPILE
4935 Note: If you wish to generate Windows versions of the utilities in
4936 the tools directory you can use the MinGW toolchain
4937 (http://www.mingw.org). Set your HOST tools to the MinGW
4938 toolchain and execute 'make tools'. For example:
4940 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
4942 Binaries such as tools/mkimage.exe will be created which can
4943 be executed on computers running Windows.
4945 U-Boot is intended to be simple to build. After installing the
4946 sources you must configure U-Boot for one specific board type. This
4951 where "NAME_defconfig" is the name of one of the existing configu-
4952 rations; see boards.cfg for supported names.
4954 Note: for some board special configuration names may exist; check if
4955 additional information is available from the board vendor; for
4956 instance, the TQM823L systems are available without (standard)
4957 or with LCD support. You can select such additional "features"
4958 when choosing the configuration, i. e.
4960 make TQM823L_defconfig
4961 - will configure for a plain TQM823L, i. e. no LCD support
4963 make TQM823L_LCD_defconfig
4964 - will configure for a TQM823L with U-Boot console on LCD
4969 Finally, type "make all", and you should get some working U-Boot
4970 images ready for download to / installation on your system:
4972 - "u-boot.bin" is a raw binary image
4973 - "u-boot" is an image in ELF binary format
4974 - "u-boot.srec" is in Motorola S-Record format
4976 By default the build is performed locally and the objects are saved
4977 in the source directory. One of the two methods can be used to change
4978 this behavior and build U-Boot to some external directory:
4980 1. Add O= to the make command line invocations:
4982 make O=/tmp/build distclean
4983 make O=/tmp/build NAME_defconfig
4984 make O=/tmp/build all
4986 2. Set environment variable KBUILD_OUTPUT to point to the desired location:
4988 export KBUILD_OUTPUT=/tmp/build
4993 Note that the command line "O=" setting overrides the KBUILD_OUTPUT environment
4997 Please be aware that the Makefiles assume you are using GNU make, so
4998 for instance on NetBSD you might need to use "gmake" instead of
5002 If the system board that you have is not listed, then you will need
5003 to port U-Boot to your hardware platform. To do this, follow these
5006 1. Create a new directory to hold your board specific code. Add any
5007 files you need. In your board directory, you will need at least
5008 the "Makefile" and a "<board>.c".
5009 2. Create a new configuration file "include/configs/<board>.h" for
5011 3. If you're porting U-Boot to a new CPU, then also create a new
5012 directory to hold your CPU specific code. Add any files you need.
5013 4. Run "make <board>_defconfig" with your new name.
5014 5. Type "make", and you should get a working "u-boot.srec" file
5015 to be installed on your target system.
5016 6. Debug and solve any problems that might arise.
5017 [Of course, this last step is much harder than it sounds.]
5020 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
5021 ==============================================================
5023 If you have modified U-Boot sources (for instance added a new board
5024 or support for new devices, a new CPU, etc.) you are expected to
5025 provide feedback to the other developers. The feedback normally takes
5026 the form of a "patch", i. e. a context diff against a certain (latest
5027 official or latest in the git repository) version of U-Boot sources.
5029 But before you submit such a patch, please verify that your modifi-
5030 cation did not break existing code. At least make sure that *ALL* of
5031 the supported boards compile WITHOUT ANY compiler warnings. To do so,
5032 just run the buildman script (tools/buildman/buildman), which will
5033 configure and build U-Boot for ALL supported system. Be warned, this
5034 will take a while. Please see the buildman README, or run 'buildman -H'
5038 See also "U-Boot Porting Guide" below.
5041 Monitor Commands - Overview:
5042 ============================
5044 go - start application at address 'addr'
5045 run - run commands in an environment variable
5046 bootm - boot application image from memory
5047 bootp - boot image via network using BootP/TFTP protocol
5048 bootz - boot zImage from memory
5049 tftpboot- boot image via network using TFTP protocol
5050 and env variables "ipaddr" and "serverip"
5051 (and eventually "gatewayip")
5052 tftpput - upload a file via network using TFTP protocol
5053 rarpboot- boot image via network using RARP/TFTP protocol
5054 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
5055 loads - load S-Record file over serial line
5056 loadb - load binary file over serial line (kermit mode)
5058 mm - memory modify (auto-incrementing)
5059 nm - memory modify (constant address)
5060 mw - memory write (fill)
5062 cmp - memory compare
5063 crc32 - checksum calculation
5064 i2c - I2C sub-system
5065 sspi - SPI utility commands
5066 base - print or set address offset
5067 printenv- print environment variables
5068 setenv - set environment variables
5069 saveenv - save environment variables to persistent storage
5070 protect - enable or disable FLASH write protection
5071 erase - erase FLASH memory
5072 flinfo - print FLASH memory information
5073 nand - NAND memory operations (see doc/README.nand)
5074 bdinfo - print Board Info structure
5075 iminfo - print header information for application image
5076 coninfo - print console devices and informations
5077 ide - IDE sub-system
5078 loop - infinite loop on address range
5079 loopw - infinite write loop on address range
5080 mtest - simple RAM test
5081 icache - enable or disable instruction cache
5082 dcache - enable or disable data cache
5083 reset - Perform RESET of the CPU
5084 echo - echo args to console
5085 version - print monitor version
5086 help - print online help
5087 ? - alias for 'help'
5090 Monitor Commands - Detailed Description:
5091 ========================================
5095 For now: just type "help <command>".
5098 Environment Variables:
5099 ======================
5101 U-Boot supports user configuration using Environment Variables which
5102 can be made persistent by saving to Flash memory.
5104 Environment Variables are set using "setenv", printed using
5105 "printenv", and saved to Flash using "saveenv". Using "setenv"
5106 without a value can be used to delete a variable from the
5107 environment. As long as you don't save the environment you are
5108 working with an in-memory copy. In case the Flash area containing the
5109 environment is erased by accident, a default environment is provided.
5111 Some configuration options can be set using Environment Variables.
5113 List of environment variables (most likely not complete):
5115 baudrate - see CONFIG_BAUDRATE
5117 bootdelay - see CONFIG_BOOTDELAY
5119 bootcmd - see CONFIG_BOOTCOMMAND
5121 bootargs - Boot arguments when booting an RTOS image
5123 bootfile - Name of the image to load with TFTP
5125 bootm_low - Memory range available for image processing in the bootm
5126 command can be restricted. This variable is given as
5127 a hexadecimal number and defines lowest address allowed
5128 for use by the bootm command. See also "bootm_size"
5129 environment variable. Address defined by "bootm_low" is
5130 also the base of the initial memory mapping for the Linux
5131 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
5134 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
5135 This variable is given as a hexadecimal number and it
5136 defines the size of the memory region starting at base
5137 address bootm_low that is accessible by the Linux kernel
5138 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
5139 as the default value if it is defined, and bootm_size is
5142 bootm_size - Memory range available for image processing in the bootm
5143 command can be restricted. This variable is given as
5144 a hexadecimal number and defines the size of the region
5145 allowed for use by the bootm command. See also "bootm_low"
5146 environment variable.
5148 updatefile - Location of the software update file on a TFTP server, used
5149 by the automatic software update feature. Please refer to
5150 documentation in doc/README.update for more details.
5152 autoload - if set to "no" (any string beginning with 'n'),
5153 "bootp" will just load perform a lookup of the
5154 configuration from the BOOTP server, but not try to
5155 load any image using TFTP
5157 autostart - if set to "yes", an image loaded using the "bootp",
5158 "rarpboot", "tftpboot" or "diskboot" commands will
5159 be automatically started (by internally calling
5162 If set to "no", a standalone image passed to the
5163 "bootm" command will be copied to the load address
5164 (and eventually uncompressed), but NOT be started.
5165 This can be used to load and uncompress arbitrary
5168 fdt_high - if set this restricts the maximum address that the
5169 flattened device tree will be copied into upon boot.
5170 For example, if you have a system with 1 GB memory
5171 at physical address 0x10000000, while Linux kernel
5172 only recognizes the first 704 MB as low memory, you
5173 may need to set fdt_high as 0x3C000000 to have the
5174 device tree blob be copied to the maximum address
5175 of the 704 MB low memory, so that Linux kernel can
5176 access it during the boot procedure.
5178 If this is set to the special value 0xFFFFFFFF then
5179 the fdt will not be copied at all on boot. For this
5180 to work it must reside in writable memory, have
5181 sufficient padding on the end of it for u-boot to
5182 add the information it needs into it, and the memory
5183 must be accessible by the kernel.
5185 fdtcontroladdr- if set this is the address of the control flattened
5186 device tree used by U-Boot when CONFIG_OF_CONTROL is
5189 i2cfast - (PPC405GP|PPC405EP only)
5190 if set to 'y' configures Linux I2C driver for fast
5191 mode (400kHZ). This environment variable is used in
5192 initialization code. So, for changes to be effective
5193 it must be saved and board must be reset.
5195 initrd_high - restrict positioning of initrd images:
5196 If this variable is not set, initrd images will be
5197 copied to the highest possible address in RAM; this
5198 is usually what you want since it allows for
5199 maximum initrd size. If for some reason you want to
5200 make sure that the initrd image is loaded below the
5201 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
5202 variable to a value of "no" or "off" or "0".
5203 Alternatively, you can set it to a maximum upper
5204 address to use (U-Boot will still check that it
5205 does not overwrite the U-Boot stack and data).
5207 For instance, when you have a system with 16 MB
5208 RAM, and want to reserve 4 MB from use by Linux,
5209 you can do this by adding "mem=12M" to the value of
5210 the "bootargs" variable. However, now you must make
5211 sure that the initrd image is placed in the first
5212 12 MB as well - this can be done with
5214 setenv initrd_high 00c00000
5216 If you set initrd_high to 0xFFFFFFFF, this is an
5217 indication to U-Boot that all addresses are legal
5218 for the Linux kernel, including addresses in flash
5219 memory. In this case U-Boot will NOT COPY the
5220 ramdisk at all. This may be useful to reduce the
5221 boot time on your system, but requires that this
5222 feature is supported by your Linux kernel.
5224 ipaddr - IP address; needed for tftpboot command
5226 loadaddr - Default load address for commands like "bootp",
5227 "rarpboot", "tftpboot", "loadb" or "diskboot"
5229 loads_echo - see CONFIG_LOADS_ECHO
5231 serverip - TFTP server IP address; needed for tftpboot command
5233 bootretry - see CONFIG_BOOT_RETRY_TIME
5235 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
5237 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
5239 ethprime - controls which interface is used first.
5241 ethact - controls which interface is currently active.
5242 For example you can do the following
5244 => setenv ethact FEC
5245 => ping 192.168.0.1 # traffic sent on FEC
5246 => setenv ethact SCC
5247 => ping 10.0.0.1 # traffic sent on SCC
5249 ethrotate - When set to "no" U-Boot does not go through all
5250 available network interfaces.
5251 It just stays at the currently selected interface.
5253 netretry - When set to "no" each network operation will
5254 either succeed or fail without retrying.
5255 When set to "once" the network operation will
5256 fail when all the available network interfaces
5257 are tried once without success.
5258 Useful on scripts which control the retry operation
5261 npe_ucode - set load address for the NPE microcode
5263 silent_linux - If set then Linux will be told to boot silently, by
5264 changing the console to be empty. If "yes" it will be
5265 made silent. If "no" it will not be made silent. If
5266 unset, then it will be made silent if the U-Boot console
5269 tftpsrcp - If this is set, the value is used for TFTP's
5272 tftpdstp - If this is set, the value is used for TFTP's UDP
5273 destination port instead of the Well Know Port 69.
5275 tftpblocksize - Block size to use for TFTP transfers; if not set,
5276 we use the TFTP server's default block size
5278 tftptimeout - Retransmission timeout for TFTP packets (in milli-
5279 seconds, minimum value is 1000 = 1 second). Defines
5280 when a packet is considered to be lost so it has to
5281 be retransmitted. The default is 5000 = 5 seconds.
5282 Lowering this value may make downloads succeed
5283 faster in networks with high packet loss rates or
5284 with unreliable TFTP servers.
5286 tftptimeoutcountmax - maximum count of TFTP timeouts (no
5287 unit, minimum value = 0). Defines how many timeouts
5288 can happen during a single file transfer before that
5289 transfer is aborted. The default is 10, and 0 means
5290 'no timeouts allowed'. Increasing this value may help
5291 downloads succeed with high packet loss rates, or with
5292 unreliable TFTP servers or client hardware.
5294 vlan - When set to a value < 4095 the traffic over
5295 Ethernet is encapsulated/received over 802.1q
5298 bootpretryperiod - Period during which BOOTP/DHCP sends retries.
5299 Unsigned value, in milliseconds. If not set, the period will
5300 be either the default (28000), or a value based on
5301 CONFIG_NET_RETRY_COUNT, if defined. This value has
5302 precedence over the valu based on CONFIG_NET_RETRY_COUNT.
5304 The following image location variables contain the location of images
5305 used in booting. The "Image" column gives the role of the image and is
5306 not an environment variable name. The other columns are environment
5307 variable names. "File Name" gives the name of the file on a TFTP
5308 server, "RAM Address" gives the location in RAM the image will be
5309 loaded to, and "Flash Location" gives the image's address in NOR
5310 flash or offset in NAND flash.
5312 *Note* - these variables don't have to be defined for all boards, some
5313 boards currently use other variables for these purposes, and some
5314 boards use these variables for other purposes.
5316 Image File Name RAM Address Flash Location
5317 ----- --------- ----------- --------------
5318 u-boot u-boot u-boot_addr_r u-boot_addr
5319 Linux kernel bootfile kernel_addr_r kernel_addr
5320 device tree blob fdtfile fdt_addr_r fdt_addr
5321 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
5323 The following environment variables may be used and automatically
5324 updated by the network boot commands ("bootp" and "rarpboot"),
5325 depending the information provided by your boot server:
5327 bootfile - see above
5328 dnsip - IP address of your Domain Name Server
5329 dnsip2 - IP address of your secondary Domain Name Server
5330 gatewayip - IP address of the Gateway (Router) to use
5331 hostname - Target hostname
5333 netmask - Subnet Mask
5334 rootpath - Pathname of the root filesystem on the NFS server
5335 serverip - see above
5338 There are two special Environment Variables:
5340 serial# - contains hardware identification information such
5341 as type string and/or serial number
5342 ethaddr - Ethernet address
5344 These variables can be set only once (usually during manufacturing of
5345 the board). U-Boot refuses to delete or overwrite these variables
5346 once they have been set once.
5349 Further special Environment Variables:
5351 ver - Contains the U-Boot version string as printed
5352 with the "version" command. This variable is
5353 readonly (see CONFIG_VERSION_VARIABLE).
5356 Please note that changes to some configuration parameters may take
5357 only effect after the next boot (yes, that's just like Windoze :-).
5360 Callback functions for environment variables:
5361 ---------------------------------------------
5363 For some environment variables, the behavior of u-boot needs to change
5364 when their values are changed. This functionality allows functions to
5365 be associated with arbitrary variables. On creation, overwrite, or
5366 deletion, the callback will provide the opportunity for some side
5367 effect to happen or for the change to be rejected.
5369 The callbacks are named and associated with a function using the
5370 U_BOOT_ENV_CALLBACK macro in your board or driver code.
5372 These callbacks are associated with variables in one of two ways. The
5373 static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC
5374 in the board configuration to a string that defines a list of
5375 associations. The list must be in the following format:
5377 entry = variable_name[:callback_name]
5380 If the callback name is not specified, then the callback is deleted.
5381 Spaces are also allowed anywhere in the list.
5383 Callbacks can also be associated by defining the ".callbacks" variable
5384 with the same list format above. Any association in ".callbacks" will
5385 override any association in the static list. You can define
5386 CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the
5387 ".callbacks" environment variable in the default or embedded environment.
5389 If CONFIG_REGEX is defined, the variable_name above is evaluated as a
5390 regular expression. This allows multiple variables to be connected to
5391 the same callback without explicitly listing them all out.
5394 Command Line Parsing:
5395 =====================
5397 There are two different command line parsers available with U-Boot:
5398 the old "simple" one, and the much more powerful "hush" shell:
5400 Old, simple command line parser:
5401 --------------------------------
5403 - supports environment variables (through setenv / saveenv commands)
5404 - several commands on one line, separated by ';'
5405 - variable substitution using "... ${name} ..." syntax
5406 - special characters ('$', ';') can be escaped by prefixing with '\',
5408 setenv bootcmd bootm \${address}
5409 - You can also escape text by enclosing in single apostrophes, for example:
5410 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
5415 - similar to Bourne shell, with control structures like
5416 if...then...else...fi, for...do...done; while...do...done,
5417 until...do...done, ...
5418 - supports environment ("global") variables (through setenv / saveenv
5419 commands) and local shell variables (through standard shell syntax
5420 "name=value"); only environment variables can be used with "run"
5426 (1) If a command line (or an environment variable executed by a "run"
5427 command) contains several commands separated by semicolon, and
5428 one of these commands fails, then the remaining commands will be
5431 (2) If you execute several variables with one call to run (i. e.
5432 calling run with a list of variables as arguments), any failing
5433 command will cause "run" to terminate, i. e. the remaining
5434 variables are not executed.
5436 Note for Redundant Ethernet Interfaces:
5437 =======================================
5439 Some boards come with redundant Ethernet interfaces; U-Boot supports
5440 such configurations and is capable of automatic selection of a
5441 "working" interface when needed. MAC assignment works as follows:
5443 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
5444 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
5445 "eth1addr" (=>eth1), "eth2addr", ...
5447 If the network interface stores some valid MAC address (for instance
5448 in SROM), this is used as default address if there is NO correspon-
5449 ding setting in the environment; if the corresponding environment
5450 variable is set, this overrides the settings in the card; that means:
5452 o If the SROM has a valid MAC address, and there is no address in the
5453 environment, the SROM's address is used.
5455 o If there is no valid address in the SROM, and a definition in the
5456 environment exists, then the value from the environment variable is
5459 o If both the SROM and the environment contain a MAC address, and
5460 both addresses are the same, this MAC address is used.
5462 o If both the SROM and the environment contain a MAC address, and the
5463 addresses differ, the value from the environment is used and a
5466 o If neither SROM nor the environment contain a MAC address, an error
5467 is raised. If CONFIG_NET_RANDOM_ETHADDR is defined, then in this case
5468 a random, locally-assigned MAC is used.
5470 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
5471 will be programmed into hardware as part of the initialization process. This
5472 may be skipped by setting the appropriate 'ethmacskip' environment variable.
5473 The naming convention is as follows:
5474 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
5479 U-Boot is capable of booting (and performing other auxiliary operations on)
5480 images in two formats:
5482 New uImage format (FIT)
5483 -----------------------
5485 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
5486 to Flattened Device Tree). It allows the use of images with multiple
5487 components (several kernels, ramdisks, etc.), with contents protected by
5488 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
5494 Old image format is based on binary files which can be basically anything,
5495 preceded by a special header; see the definitions in include/image.h for
5496 details; basically, the header defines the following image properties:
5498 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
5499 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
5500 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
5501 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
5503 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
5504 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
5505 Currently supported: ARM, AVR32, Intel x86, MIPS, NDS32, Nios II, PowerPC).
5506 * Compression Type (uncompressed, gzip, bzip2)
5512 The header is marked by a special Magic Number, and both the header
5513 and the data portions of the image are secured against corruption by
5520 Although U-Boot should support any OS or standalone application
5521 easily, the main focus has always been on Linux during the design of
5524 U-Boot includes many features that so far have been part of some
5525 special "boot loader" code within the Linux kernel. Also, any
5526 "initrd" images to be used are no longer part of one big Linux image;
5527 instead, kernel and "initrd" are separate images. This implementation
5528 serves several purposes:
5530 - the same features can be used for other OS or standalone
5531 applications (for instance: using compressed images to reduce the
5532 Flash memory footprint)
5534 - it becomes much easier to port new Linux kernel versions because
5535 lots of low-level, hardware dependent stuff are done by U-Boot
5537 - the same Linux kernel image can now be used with different "initrd"
5538 images; of course this also means that different kernel images can
5539 be run with the same "initrd". This makes testing easier (you don't
5540 have to build a new "zImage.initrd" Linux image when you just
5541 change a file in your "initrd"). Also, a field-upgrade of the
5542 software is easier now.
5548 Porting Linux to U-Boot based systems:
5549 ---------------------------------------
5551 U-Boot cannot save you from doing all the necessary modifications to
5552 configure the Linux device drivers for use with your target hardware
5553 (no, we don't intend to provide a full virtual machine interface to
5556 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
5558 Just make sure your machine specific header file (for instance
5559 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
5560 Information structure as we define in include/asm-<arch>/u-boot.h,
5561 and make sure that your definition of IMAP_ADDR uses the same value
5562 as your U-Boot configuration in CONFIG_SYS_IMMR.
5564 Note that U-Boot now has a driver model, a unified model for drivers.
5565 If you are adding a new driver, plumb it into driver model. If there
5566 is no uclass available, you are encouraged to create one. See
5570 Configuring the Linux kernel:
5571 -----------------------------
5573 No specific requirements for U-Boot. Make sure you have some root
5574 device (initial ramdisk, NFS) for your target system.
5577 Building a Linux Image:
5578 -----------------------
5580 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
5581 not used. If you use recent kernel source, a new build target
5582 "uImage" will exist which automatically builds an image usable by
5583 U-Boot. Most older kernels also have support for a "pImage" target,
5584 which was introduced for our predecessor project PPCBoot and uses a
5585 100% compatible format.
5589 make TQM850L_defconfig
5594 The "uImage" build target uses a special tool (in 'tools/mkimage') to
5595 encapsulate a compressed Linux kernel image with header information,
5596 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
5598 * build a standard "vmlinux" kernel image (in ELF binary format):
5600 * convert the kernel into a raw binary image:
5602 ${CROSS_COMPILE}-objcopy -O binary \
5603 -R .note -R .comment \
5604 -S vmlinux linux.bin
5606 * compress the binary image:
5610 * package compressed binary image for U-Boot:
5612 mkimage -A ppc -O linux -T kernel -C gzip \
5613 -a 0 -e 0 -n "Linux Kernel Image" \
5614 -d linux.bin.gz uImage
5617 The "mkimage" tool can also be used to create ramdisk images for use
5618 with U-Boot, either separated from the Linux kernel image, or
5619 combined into one file. "mkimage" encapsulates the images with a 64
5620 byte header containing information about target architecture,
5621 operating system, image type, compression method, entry points, time
5622 stamp, CRC32 checksums, etc.
5624 "mkimage" can be called in two ways: to verify existing images and
5625 print the header information, or to build new images.
5627 In the first form (with "-l" option) mkimage lists the information
5628 contained in the header of an existing U-Boot image; this includes
5629 checksum verification:
5631 tools/mkimage -l image
5632 -l ==> list image header information
5634 The second form (with "-d" option) is used to build a U-Boot image
5635 from a "data file" which is used as image payload:
5637 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
5638 -n name -d data_file image
5639 -A ==> set architecture to 'arch'
5640 -O ==> set operating system to 'os'
5641 -T ==> set image type to 'type'
5642 -C ==> set compression type 'comp'
5643 -a ==> set load address to 'addr' (hex)
5644 -e ==> set entry point to 'ep' (hex)
5645 -n ==> set image name to 'name'
5646 -d ==> use image data from 'datafile'
5648 Right now, all Linux kernels for PowerPC systems use the same load
5649 address (0x00000000), but the entry point address depends on the
5652 - 2.2.x kernels have the entry point at 0x0000000C,
5653 - 2.3.x and later kernels have the entry point at 0x00000000.
5655 So a typical call to build a U-Boot image would read:
5657 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5658 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
5659 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
5660 > examples/uImage.TQM850L
5661 Image Name: 2.4.4 kernel for TQM850L
5662 Created: Wed Jul 19 02:34:59 2000
5663 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5664 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5665 Load Address: 0x00000000
5666 Entry Point: 0x00000000
5668 To verify the contents of the image (or check for corruption):
5670 -> tools/mkimage -l examples/uImage.TQM850L
5671 Image Name: 2.4.4 kernel for TQM850L
5672 Created: Wed Jul 19 02:34:59 2000
5673 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5674 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5675 Load Address: 0x00000000
5676 Entry Point: 0x00000000
5678 NOTE: for embedded systems where boot time is critical you can trade
5679 speed for memory and install an UNCOMPRESSED image instead: this
5680 needs more space in Flash, but boots much faster since it does not
5681 need to be uncompressed:
5683 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
5684 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5685 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
5686 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
5687 > examples/uImage.TQM850L-uncompressed
5688 Image Name: 2.4.4 kernel for TQM850L
5689 Created: Wed Jul 19 02:34:59 2000
5690 Image Type: PowerPC Linux Kernel Image (uncompressed)
5691 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
5692 Load Address: 0x00000000
5693 Entry Point: 0x00000000
5696 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
5697 when your kernel is intended to use an initial ramdisk:
5699 -> tools/mkimage -n 'Simple Ramdisk Image' \
5700 > -A ppc -O linux -T ramdisk -C gzip \
5701 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
5702 Image Name: Simple Ramdisk Image
5703 Created: Wed Jan 12 14:01:50 2000
5704 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5705 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
5706 Load Address: 0x00000000
5707 Entry Point: 0x00000000
5709 The "dumpimage" is a tool to disassemble images built by mkimage. Its "-i"
5710 option performs the converse operation of the mkimage's second form (the "-d"
5711 option). Given an image built by mkimage, the dumpimage extracts a "data file"
5714 tools/dumpimage -i image -T type -p position data_file
5715 -i ==> extract from the 'image' a specific 'data_file'
5716 -T ==> set image type to 'type'
5717 -p ==> 'position' (starting at 0) of the 'data_file' inside the 'image'
5720 Installing a Linux Image:
5721 -------------------------
5723 To downloading a U-Boot image over the serial (console) interface,
5724 you must convert the image to S-Record format:
5726 objcopy -I binary -O srec examples/image examples/image.srec
5728 The 'objcopy' does not understand the information in the U-Boot
5729 image header, so the resulting S-Record file will be relative to
5730 address 0x00000000. To load it to a given address, you need to
5731 specify the target address as 'offset' parameter with the 'loads'
5734 Example: install the image to address 0x40100000 (which on the
5735 TQM8xxL is in the first Flash bank):
5737 => erase 40100000 401FFFFF
5743 ## Ready for S-Record download ...
5744 ~>examples/image.srec
5745 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
5747 15989 15990 15991 15992
5748 [file transfer complete]
5750 ## Start Addr = 0x00000000
5753 You can check the success of the download using the 'iminfo' command;
5754 this includes a checksum verification so you can be sure no data
5755 corruption happened:
5759 ## Checking Image at 40100000 ...
5760 Image Name: 2.2.13 for initrd on TQM850L
5761 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5762 Data Size: 335725 Bytes = 327 kB = 0 MB
5763 Load Address: 00000000
5764 Entry Point: 0000000c
5765 Verifying Checksum ... OK
5771 The "bootm" command is used to boot an application that is stored in
5772 memory (RAM or Flash). In case of a Linux kernel image, the contents
5773 of the "bootargs" environment variable is passed to the kernel as
5774 parameters. You can check and modify this variable using the
5775 "printenv" and "setenv" commands:
5778 => printenv bootargs
5779 bootargs=root=/dev/ram
5781 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5783 => printenv bootargs
5784 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5787 ## Booting Linux kernel at 40020000 ...
5788 Image Name: 2.2.13 for NFS on TQM850L
5789 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5790 Data Size: 381681 Bytes = 372 kB = 0 MB
5791 Load Address: 00000000
5792 Entry Point: 0000000c
5793 Verifying Checksum ... OK
5794 Uncompressing Kernel Image ... OK
5795 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
5796 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5797 time_init: decrementer frequency = 187500000/60
5798 Calibrating delay loop... 49.77 BogoMIPS
5799 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
5802 If you want to boot a Linux kernel with initial RAM disk, you pass
5803 the memory addresses of both the kernel and the initrd image (PPBCOOT
5804 format!) to the "bootm" command:
5806 => imi 40100000 40200000
5808 ## Checking Image at 40100000 ...
5809 Image Name: 2.2.13 for initrd on TQM850L
5810 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5811 Data Size: 335725 Bytes = 327 kB = 0 MB
5812 Load Address: 00000000
5813 Entry Point: 0000000c
5814 Verifying Checksum ... OK
5816 ## Checking Image at 40200000 ...
5817 Image Name: Simple Ramdisk Image
5818 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5819 Data Size: 566530 Bytes = 553 kB = 0 MB
5820 Load Address: 00000000
5821 Entry Point: 00000000
5822 Verifying Checksum ... OK
5824 => bootm 40100000 40200000
5825 ## Booting Linux kernel at 40100000 ...
5826 Image Name: 2.2.13 for initrd on TQM850L
5827 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5828 Data Size: 335725 Bytes = 327 kB = 0 MB
5829 Load Address: 00000000
5830 Entry Point: 0000000c
5831 Verifying Checksum ... OK
5832 Uncompressing Kernel Image ... OK
5833 ## Loading RAMDisk Image at 40200000 ...
5834 Image Name: Simple Ramdisk Image
5835 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5836 Data Size: 566530 Bytes = 553 kB = 0 MB
5837 Load Address: 00000000
5838 Entry Point: 00000000
5839 Verifying Checksum ... OK
5840 Loading Ramdisk ... OK
5841 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
5842 Boot arguments: root=/dev/ram
5843 time_init: decrementer frequency = 187500000/60
5844 Calibrating delay loop... 49.77 BogoMIPS
5846 RAMDISK: Compressed image found at block 0
5847 VFS: Mounted root (ext2 filesystem).
5851 Boot Linux and pass a flat device tree:
5854 First, U-Boot must be compiled with the appropriate defines. See the section
5855 titled "Linux Kernel Interface" above for a more in depth explanation. The
5856 following is an example of how to start a kernel and pass an updated
5862 oft=oftrees/mpc8540ads.dtb
5863 => tftp $oftaddr $oft
5864 Speed: 1000, full duplex
5866 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
5867 Filename 'oftrees/mpc8540ads.dtb'.
5868 Load address: 0x300000
5871 Bytes transferred = 4106 (100a hex)
5872 => tftp $loadaddr $bootfile
5873 Speed: 1000, full duplex
5875 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
5877 Load address: 0x200000
5878 Loading:############
5880 Bytes transferred = 1029407 (fb51f hex)
5885 => bootm $loadaddr - $oftaddr
5886 ## Booting image at 00200000 ...
5887 Image Name: Linux-2.6.17-dirty
5888 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5889 Data Size: 1029343 Bytes = 1005.2 kB
5890 Load Address: 00000000
5891 Entry Point: 00000000
5892 Verifying Checksum ... OK
5893 Uncompressing Kernel Image ... OK
5894 Booting using flat device tree at 0x300000
5895 Using MPC85xx ADS machine description
5896 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
5900 More About U-Boot Image Types:
5901 ------------------------------
5903 U-Boot supports the following image types:
5905 "Standalone Programs" are directly runnable in the environment
5906 provided by U-Boot; it is expected that (if they behave
5907 well) you can continue to work in U-Boot after return from
5908 the Standalone Program.
5909 "OS Kernel Images" are usually images of some Embedded OS which
5910 will take over control completely. Usually these programs
5911 will install their own set of exception handlers, device
5912 drivers, set up the MMU, etc. - this means, that you cannot
5913 expect to re-enter U-Boot except by resetting the CPU.
5914 "RAMDisk Images" are more or less just data blocks, and their
5915 parameters (address, size) are passed to an OS kernel that is
5917 "Multi-File Images" contain several images, typically an OS
5918 (Linux) kernel image and one or more data images like
5919 RAMDisks. This construct is useful for instance when you want
5920 to boot over the network using BOOTP etc., where the boot
5921 server provides just a single image file, but you want to get
5922 for instance an OS kernel and a RAMDisk image.
5924 "Multi-File Images" start with a list of image sizes, each
5925 image size (in bytes) specified by an "uint32_t" in network
5926 byte order. This list is terminated by an "(uint32_t)0".
5927 Immediately after the terminating 0 follow the images, one by
5928 one, all aligned on "uint32_t" boundaries (size rounded up to
5929 a multiple of 4 bytes).
5931 "Firmware Images" are binary images containing firmware (like
5932 U-Boot or FPGA images) which usually will be programmed to
5935 "Script files" are command sequences that will be executed by
5936 U-Boot's command interpreter; this feature is especially
5937 useful when you configure U-Boot to use a real shell (hush)
5938 as command interpreter.
5940 Booting the Linux zImage:
5941 -------------------------
5943 On some platforms, it's possible to boot Linux zImage. This is done
5944 using the "bootz" command. The syntax of "bootz" command is the same
5945 as the syntax of "bootm" command.
5947 Note, defining the CONFIG_SUPPORT_RAW_INITRD allows user to supply
5948 kernel with raw initrd images. The syntax is slightly different, the
5949 address of the initrd must be augmented by it's size, in the following
5950 format: "<initrd addres>:<initrd size>".
5956 One of the features of U-Boot is that you can dynamically load and
5957 run "standalone" applications, which can use some resources of
5958 U-Boot like console I/O functions or interrupt services.
5960 Two simple examples are included with the sources:
5965 'examples/hello_world.c' contains a small "Hello World" Demo
5966 application; it is automatically compiled when you build U-Boot.
5967 It's configured to run at address 0x00040004, so you can play with it
5971 ## Ready for S-Record download ...
5972 ~>examples/hello_world.srec
5973 1 2 3 4 5 6 7 8 9 10 11 ...
5974 [file transfer complete]
5976 ## Start Addr = 0x00040004
5978 => go 40004 Hello World! This is a test.
5979 ## Starting application at 0x00040004 ...
5990 Hit any key to exit ...
5992 ## Application terminated, rc = 0x0
5994 Another example, which demonstrates how to register a CPM interrupt
5995 handler with the U-Boot code, can be found in 'examples/timer.c'.
5996 Here, a CPM timer is set up to generate an interrupt every second.
5997 The interrupt service routine is trivial, just printing a '.'
5998 character, but this is just a demo program. The application can be
5999 controlled by the following keys:
6001 ? - print current values og the CPM Timer registers
6002 b - enable interrupts and start timer
6003 e - stop timer and disable interrupts
6004 q - quit application
6007 ## Ready for S-Record download ...
6008 ~>examples/timer.srec
6009 1 2 3 4 5 6 7 8 9 10 11 ...
6010 [file transfer complete]
6012 ## Start Addr = 0x00040004
6015 ## Starting application at 0x00040004 ...
6018 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
6021 [q, b, e, ?] Set interval 1000000 us
6024 [q, b, e, ?] ........
6025 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
6028 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
6031 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
6034 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
6036 [q, b, e, ?] ...Stopping timer
6038 [q, b, e, ?] ## Application terminated, rc = 0x0
6044 Over time, many people have reported problems when trying to use the
6045 "minicom" terminal emulation program for serial download. I (wd)
6046 consider minicom to be broken, and recommend not to use it. Under
6047 Unix, I recommend to use C-Kermit for general purpose use (and
6048 especially for kermit binary protocol download ("loadb" command), and
6049 use "cu" for S-Record download ("loads" command). See
6050 http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
6051 for help with kermit.
6054 Nevertheless, if you absolutely want to use it try adding this
6055 configuration to your "File transfer protocols" section:
6057 Name Program Name U/D FullScr IO-Red. Multi
6058 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
6059 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
6065 Starting at version 0.9.2, U-Boot supports NetBSD both as host
6066 (build U-Boot) and target system (boots NetBSD/mpc8xx).
6068 Building requires a cross environment; it is known to work on
6069 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
6070 need gmake since the Makefiles are not compatible with BSD make).
6071 Note that the cross-powerpc package does not install include files;
6072 attempting to build U-Boot will fail because <machine/ansi.h> is
6073 missing. This file has to be installed and patched manually:
6075 # cd /usr/pkg/cross/powerpc-netbsd/include
6077 # ln -s powerpc machine
6078 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
6079 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
6081 Native builds *don't* work due to incompatibilities between native
6082 and U-Boot include files.
6084 Booting assumes that (the first part of) the image booted is a
6085 stage-2 loader which in turn loads and then invokes the kernel
6086 proper. Loader sources will eventually appear in the NetBSD source
6087 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
6088 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
6091 Implementation Internals:
6092 =========================
6094 The following is not intended to be a complete description of every
6095 implementation detail. However, it should help to understand the
6096 inner workings of U-Boot and make it easier to port it to custom
6100 Initial Stack, Global Data:
6101 ---------------------------
6103 The implementation of U-Boot is complicated by the fact that U-Boot
6104 starts running out of ROM (flash memory), usually without access to
6105 system RAM (because the memory controller is not initialized yet).
6106 This means that we don't have writable Data or BSS segments, and BSS
6107 is not initialized as zero. To be able to get a C environment working
6108 at all, we have to allocate at least a minimal stack. Implementation
6109 options for this are defined and restricted by the CPU used: Some CPU
6110 models provide on-chip memory (like the IMMR area on MPC8xx and
6111 MPC826x processors), on others (parts of) the data cache can be
6112 locked as (mis-) used as memory, etc.
6114 Chris Hallinan posted a good summary of these issues to the
6115 U-Boot mailing list:
6117 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
6118 From: "Chris Hallinan" <clh@net1plus.com>
6119 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
6122 Correct me if I'm wrong, folks, but the way I understand it
6123 is this: Using DCACHE as initial RAM for Stack, etc, does not
6124 require any physical RAM backing up the cache. The cleverness
6125 is that the cache is being used as a temporary supply of
6126 necessary storage before the SDRAM controller is setup. It's
6127 beyond the scope of this list to explain the details, but you
6128 can see how this works by studying the cache architecture and
6129 operation in the architecture and processor-specific manuals.
6131 OCM is On Chip Memory, which I believe the 405GP has 4K. It
6132 is another option for the system designer to use as an
6133 initial stack/RAM area prior to SDRAM being available. Either
6134 option should work for you. Using CS 4 should be fine if your
6135 board designers haven't used it for something that would
6136 cause you grief during the initial boot! It is frequently not
6139 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
6140 with your processor/board/system design. The default value
6141 you will find in any recent u-boot distribution in
6142 walnut.h should work for you. I'd set it to a value larger
6143 than your SDRAM module. If you have a 64MB SDRAM module, set
6144 it above 400_0000. Just make sure your board has no resources
6145 that are supposed to respond to that address! That code in
6146 start.S has been around a while and should work as is when
6147 you get the config right.
6152 It is essential to remember this, since it has some impact on the C
6153 code for the initialization procedures:
6155 * Initialized global data (data segment) is read-only. Do not attempt
6158 * Do not use any uninitialized global data (or implicitly initialized
6159 as zero data - BSS segment) at all - this is undefined, initiali-
6160 zation is performed later (when relocating to RAM).
6162 * Stack space is very limited. Avoid big data buffers or things like
6165 Having only the stack as writable memory limits means we cannot use
6166 normal global data to share information between the code. But it
6167 turned out that the implementation of U-Boot can be greatly
6168 simplified by making a global data structure (gd_t) available to all
6169 functions. We could pass a pointer to this data as argument to _all_
6170 functions, but this would bloat the code. Instead we use a feature of
6171 the GCC compiler (Global Register Variables) to share the data: we
6172 place a pointer (gd) to the global data into a register which we
6173 reserve for this purpose.
6175 When choosing a register for such a purpose we are restricted by the
6176 relevant (E)ABI specifications for the current architecture, and by
6177 GCC's implementation.
6179 For PowerPC, the following registers have specific use:
6181 R2: reserved for system use
6182 R3-R4: parameter passing and return values
6183 R5-R10: parameter passing
6184 R13: small data area pointer
6188 (U-Boot also uses R12 as internal GOT pointer. r12
6189 is a volatile register so r12 needs to be reset when
6190 going back and forth between asm and C)
6192 ==> U-Boot will use R2 to hold a pointer to the global data
6194 Note: on PPC, we could use a static initializer (since the
6195 address of the global data structure is known at compile time),
6196 but it turned out that reserving a register results in somewhat
6197 smaller code - although the code savings are not that big (on
6198 average for all boards 752 bytes for the whole U-Boot image,
6199 624 text + 127 data).
6201 On Blackfin, the normal C ABI (except for P3) is followed as documented here:
6202 http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
6204 ==> U-Boot will use P3 to hold a pointer to the global data
6206 On ARM, the following registers are used:
6208 R0: function argument word/integer result
6209 R1-R3: function argument word
6210 R9: platform specific
6211 R10: stack limit (used only if stack checking is enabled)
6212 R11: argument (frame) pointer
6213 R12: temporary workspace
6216 R15: program counter
6218 ==> U-Boot will use R9 to hold a pointer to the global data
6220 Note: on ARM, only R_ARM_RELATIVE relocations are supported.
6222 On Nios II, the ABI is documented here:
6223 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
6225 ==> U-Boot will use gp to hold a pointer to the global data
6227 Note: on Nios II, we give "-G0" option to gcc and don't use gp
6228 to access small data sections, so gp is free.
6230 On NDS32, the following registers are used:
6232 R0-R1: argument/return
6234 R15: temporary register for assembler
6235 R16: trampoline register
6236 R28: frame pointer (FP)
6237 R29: global pointer (GP)
6238 R30: link register (LP)
6239 R31: stack pointer (SP)
6240 PC: program counter (PC)
6242 ==> U-Boot will use R10 to hold a pointer to the global data
6244 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
6245 or current versions of GCC may "optimize" the code too much.
6250 U-Boot runs in system state and uses physical addresses, i.e. the
6251 MMU is not used either for address mapping nor for memory protection.
6253 The available memory is mapped to fixed addresses using the memory
6254 controller. In this process, a contiguous block is formed for each
6255 memory type (Flash, SDRAM, SRAM), even when it consists of several
6256 physical memory banks.
6258 U-Boot is installed in the first 128 kB of the first Flash bank (on
6259 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
6260 booting and sizing and initializing DRAM, the code relocates itself
6261 to the upper end of DRAM. Immediately below the U-Boot code some
6262 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
6263 configuration setting]. Below that, a structure with global Board
6264 Info data is placed, followed by the stack (growing downward).
6266 Additionally, some exception handler code is copied to the low 8 kB
6267 of DRAM (0x00000000 ... 0x00001FFF).
6269 So a typical memory configuration with 16 MB of DRAM could look like
6272 0x0000 0000 Exception Vector code
6275 0x0000 2000 Free for Application Use
6281 0x00FB FF20 Monitor Stack (Growing downward)
6282 0x00FB FFAC Board Info Data and permanent copy of global data
6283 0x00FC 0000 Malloc Arena
6286 0x00FE 0000 RAM Copy of Monitor Code
6287 ... eventually: LCD or video framebuffer
6288 ... eventually: pRAM (Protected RAM - unchanged by reset)
6289 0x00FF FFFF [End of RAM]
6292 System Initialization:
6293 ----------------------
6295 In the reset configuration, U-Boot starts at the reset entry point
6296 (on most PowerPC systems at address 0x00000100). Because of the reset
6297 configuration for CS0# this is a mirror of the on board Flash memory.
6298 To be able to re-map memory U-Boot then jumps to its link address.
6299 To be able to implement the initialization code in C, a (small!)
6300 initial stack is set up in the internal Dual Ported RAM (in case CPUs
6301 which provide such a feature like MPC8xx or MPC8260), or in a locked
6302 part of the data cache. After that, U-Boot initializes the CPU core,
6303 the caches and the SIU.
6305 Next, all (potentially) available memory banks are mapped using a
6306 preliminary mapping. For example, we put them on 512 MB boundaries
6307 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
6308 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
6309 programmed for SDRAM access. Using the temporary configuration, a
6310 simple memory test is run that determines the size of the SDRAM
6313 When there is more than one SDRAM bank, and the banks are of
6314 different size, the largest is mapped first. For equal size, the first
6315 bank (CS2#) is mapped first. The first mapping is always for address
6316 0x00000000, with any additional banks following immediately to create
6317 contiguous memory starting from 0.
6319 Then, the monitor installs itself at the upper end of the SDRAM area
6320 and allocates memory for use by malloc() and for the global Board
6321 Info data; also, the exception vector code is copied to the low RAM
6322 pages, and the final stack is set up.
6324 Only after this relocation will you have a "normal" C environment;
6325 until that you are restricted in several ways, mostly because you are
6326 running from ROM, and because the code will have to be relocated to a
6330 U-Boot Porting Guide:
6331 ----------------------
6333 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
6337 int main(int argc, char *argv[])
6339 sighandler_t no_more_time;
6341 signal(SIGALRM, no_more_time);
6342 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
6344 if (available_money > available_manpower) {
6345 Pay consultant to port U-Boot;
6349 Download latest U-Boot source;
6351 Subscribe to u-boot mailing list;
6354 email("Hi, I am new to U-Boot, how do I get started?");
6357 Read the README file in the top level directory;
6358 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
6359 Read applicable doc/*.README;
6360 Read the source, Luke;
6361 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
6364 if (available_money > toLocalCurrency ($2500))
6367 Add a lot of aggravation and time;
6369 if (a similar board exists) { /* hopefully... */
6370 cp -a board/<similar> board/<myboard>
6371 cp include/configs/<similar>.h include/configs/<myboard>.h
6373 Create your own board support subdirectory;
6374 Create your own board include/configs/<myboard>.h file;
6376 Edit new board/<myboard> files
6377 Edit new include/configs/<myboard>.h
6382 Add / modify source code;
6386 email("Hi, I am having problems...");
6388 Send patch file to the U-Boot email list;
6389 if (reasonable critiques)
6390 Incorporate improvements from email list code review;
6392 Defend code as written;
6398 void no_more_time (int sig)
6407 All contributions to U-Boot should conform to the Linux kernel
6408 coding style; see the file "Documentation/CodingStyle" and the script
6409 "scripts/Lindent" in your Linux kernel source directory.
6411 Source files originating from a different project (for example the
6412 MTD subsystem) are generally exempt from these guidelines and are not
6413 reformatted to ease subsequent migration to newer versions of those
6416 Please note that U-Boot is implemented in C (and to some small parts in
6417 Assembler); no C++ is used, so please do not use C++ style comments (//)
6420 Please also stick to the following formatting rules:
6421 - remove any trailing white space
6422 - use TAB characters for indentation and vertical alignment, not spaces
6423 - make sure NOT to use DOS '\r\n' line feeds
6424 - do not add more than 2 consecutive empty lines to source files
6425 - do not add trailing empty lines to source files
6427 Submissions which do not conform to the standards may be returned
6428 with a request to reformat the changes.
6434 Since the number of patches for U-Boot is growing, we need to
6435 establish some rules. Submissions which do not conform to these rules
6436 may be rejected, even when they contain important and valuable stuff.
6438 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
6440 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
6441 see http://lists.denx.de/mailman/listinfo/u-boot
6443 When you send a patch, please include the following information with
6446 * For bug fixes: a description of the bug and how your patch fixes
6447 this bug. Please try to include a way of demonstrating that the
6448 patch actually fixes something.
6450 * For new features: a description of the feature and your
6453 * A CHANGELOG entry as plaintext (separate from the patch)
6455 * For major contributions, add a MAINTAINERS file with your
6456 information and associated file and directory references.
6458 * When you add support for a new board, don't forget to add a
6459 maintainer e-mail address to the boards.cfg file, too.
6461 * If your patch adds new configuration options, don't forget to
6462 document these in the README file.
6464 * The patch itself. If you are using git (which is *strongly*
6465 recommended) you can easily generate the patch using the
6466 "git format-patch". If you then use "git send-email" to send it to
6467 the U-Boot mailing list, you will avoid most of the common problems
6468 with some other mail clients.
6470 If you cannot use git, use "diff -purN OLD NEW". If your version of
6471 diff does not support these options, then get the latest version of
6474 The current directory when running this command shall be the parent
6475 directory of the U-Boot source tree (i. e. please make sure that
6476 your patch includes sufficient directory information for the
6479 We prefer patches as plain text. MIME attachments are discouraged,
6480 and compressed attachments must not be used.
6482 * If one logical set of modifications affects or creates several
6483 files, all these changes shall be submitted in a SINGLE patch file.
6485 * Changesets that contain different, unrelated modifications shall be
6486 submitted as SEPARATE patches, one patch per changeset.
6491 * Before sending the patch, run the buildman script on your patched
6492 source tree and make sure that no errors or warnings are reported
6493 for any of the boards.
6495 * Keep your modifications to the necessary minimum: A patch
6496 containing several unrelated changes or arbitrary reformats will be
6497 returned with a request to re-formatting / split it.
6499 * If you modify existing code, make sure that your new code does not
6500 add to the memory footprint of the code ;-) Small is beautiful!
6501 When adding new features, these should compile conditionally only
6502 (using #ifdef), and the resulting code with the new feature
6503 disabled must not need more memory than the old code without your
6506 * Remember that there is a size limit of 100 kB per message on the
6507 u-boot mailing list. Bigger patches will be moderated. If they are
6508 reasonable and not too big, they will be acknowledged. But patches
6509 bigger than the size limit should be avoided.
projects / platform / kernel / u-boot.git / blob