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 CONFIG_FASTBOOT_MBR_NAME
1687 The fastboot "flash" command supports writing the downloaded
1689 This occurs when the "partition name" specified on the
1690 "fastboot flash" command line matches this value.
1691 If not defined the default value "mbr" is used.
1693 - Journaling Flash filesystem support:
1694 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
1695 CONFIG_JFFS2_NAND_DEV
1696 Define these for a default partition on a NAND device
1698 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1699 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1700 Define these for a default partition on a NOR device
1702 CONFIG_SYS_JFFS_CUSTOM_PART
1703 Define this to create an own partition. You have to provide a
1704 function struct part_info* jffs2_part_info(int part_num)
1706 If you define only one JFFS2 partition you may also want to
1707 #define CONFIG_SYS_JFFS_SINGLE_PART 1
1708 to disable the command chpart. This is the default when you
1709 have not defined a custom partition
1711 - FAT(File Allocation Table) filesystem write function support:
1714 Define this to enable support for saving memory data as a
1715 file in FAT formatted partition.
1717 This will also enable the command "fatwrite" enabling the
1718 user to write files to FAT.
1720 CBFS (Coreboot Filesystem) support
1723 Define this to enable support for reading from a Coreboot
1724 filesystem. Available commands are cbfsinit, cbfsinfo, cbfsls
1727 - FAT(File Allocation Table) filesystem cluster size:
1728 CONFIG_FS_FAT_MAX_CLUSTSIZE
1730 Define the max cluster size for fat operations else
1731 a default value of 65536 will be defined.
1734 See Kconfig help for available keyboard drivers.
1738 Define this to enable a custom keyboard support.
1739 This simply calls drv_keyboard_init() which must be
1740 defined in your board-specific files. This option is deprecated
1741 and is only used by novena. For new boards, use driver model
1747 Define this to enable video support (for output to
1750 CONFIG_VIDEO_CT69000
1752 Enable Chips & Technologies 69000 Video chip
1754 CONFIG_VIDEO_SMI_LYNXEM
1755 Enable Silicon Motion SMI 712/710/810 Video chip. The
1756 video output is selected via environment 'videoout'
1757 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
1760 For the CT69000 and SMI_LYNXEM drivers, videomode is
1761 selected via environment 'videomode'. Two different ways
1763 - "videomode=num" 'num' is a standard LiLo mode numbers.
1764 Following standard modes are supported (* is default):
1766 Colors 640x480 800x600 1024x768 1152x864 1280x1024
1767 -------------+---------------------------------------------
1768 8 bits | 0x301* 0x303 0x305 0x161 0x307
1769 15 bits | 0x310 0x313 0x316 0x162 0x319
1770 16 bits | 0x311 0x314 0x317 0x163 0x31A
1771 24 bits | 0x312 0x315 0x318 ? 0x31B
1772 -------------+---------------------------------------------
1773 (i.e. setenv videomode 317; saveenv; reset;)
1775 - "videomode=bootargs" all the video parameters are parsed
1776 from the bootargs. (See drivers/video/videomodes.c)
1779 CONFIG_VIDEO_SED13806
1780 Enable Epson SED13806 driver. This driver supports 8bpp
1781 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
1782 or CONFIG_VIDEO_SED13806_16BPP
1785 Enable the Freescale DIU video driver. Reference boards for
1786 SOCs that have a DIU should define this macro to enable DIU
1787 support, and should also define these other macros:
1793 CONFIG_VIDEO_SW_CURSOR
1794 CONFIG_VGA_AS_SINGLE_DEVICE
1796 CONFIG_VIDEO_BMP_LOGO
1798 The DIU driver will look for the 'video-mode' environment
1799 variable, and if defined, enable the DIU as a console during
1800 boot. See the documentation file doc/README.video for a
1801 description of this variable.
1803 - LCD Support: CONFIG_LCD
1805 Define this to enable LCD support (for output to LCD
1806 display); also select one of the supported displays
1807 by defining one of these:
1811 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1813 CONFIG_NEC_NL6448AC33:
1815 NEC NL6448AC33-18. Active, color, single scan.
1817 CONFIG_NEC_NL6448BC20
1819 NEC NL6448BC20-08. 6.5", 640x480.
1820 Active, color, single scan.
1822 CONFIG_NEC_NL6448BC33_54
1824 NEC NL6448BC33-54. 10.4", 640x480.
1825 Active, color, single scan.
1829 Sharp 320x240. Active, color, single scan.
1830 It isn't 16x9, and I am not sure what it is.
1832 CONFIG_SHARP_LQ64D341
1834 Sharp LQ64D341 display, 640x480.
1835 Active, color, single scan.
1839 HLD1045 display, 640x480.
1840 Active, color, single scan.
1844 Optrex CBL50840-2 NF-FW 99 22 M5
1846 Hitachi LMG6912RPFC-00T
1850 320x240. Black & white.
1852 Normally display is black on white background; define
1853 CONFIG_SYS_WHITE_ON_BLACK to get it inverted.
1855 CONFIG_LCD_ALIGNMENT
1857 Normally the LCD is page-aligned (typically 4KB). If this is
1858 defined then the LCD will be aligned to this value instead.
1859 For ARM it is sometimes useful to use MMU_SECTION_SIZE
1860 here, since it is cheaper to change data cache settings on
1861 a per-section basis.
1863 CONFIG_CONSOLE_SCROLL_LINES
1865 When the console need to be scrolled, this is the number of
1866 lines to scroll by. It defaults to 1. Increasing this makes
1867 the console jump but can help speed up operation when scrolling
1872 Sometimes, for example if the display is mounted in portrait
1873 mode or even if it's mounted landscape but rotated by 180degree,
1874 we need to rotate our content of the display relative to the
1875 framebuffer, so that user can read the messages which are
1877 Once CONFIG_LCD_ROTATION is defined, the lcd_console will be
1878 initialized with a given rotation from "vl_rot" out of
1879 "vidinfo_t" which is provided by the board specific code.
1880 The value for vl_rot is coded as following (matching to
1881 fbcon=rotate:<n> linux-kernel commandline):
1882 0 = no rotation respectively 0 degree
1883 1 = 90 degree rotation
1884 2 = 180 degree rotation
1885 3 = 270 degree rotation
1887 If CONFIG_LCD_ROTATION is not defined, the console will be
1888 initialized with 0degree rotation.
1892 Support drawing of RLE8-compressed bitmaps on the LCD.
1896 Enables an 'i2c edid' command which can read EDID
1897 information over I2C from an attached LCD display.
1899 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1901 If this option is set, the environment is checked for
1902 a variable "splashimage". If found, the usual display
1903 of logo, copyright and system information on the LCD
1904 is suppressed and the BMP image at the address
1905 specified in "splashimage" is loaded instead. The
1906 console is redirected to the "nulldev", too. This
1907 allows for a "silent" boot where a splash screen is
1908 loaded very quickly after power-on.
1910 CONFIG_SPLASHIMAGE_GUARD
1912 If this option is set, then U-Boot will prevent the environment
1913 variable "splashimage" from being set to a problematic address
1914 (see doc/README.displaying-bmps).
1915 This option is useful for targets where, due to alignment
1916 restrictions, an improperly aligned BMP image will cause a data
1917 abort. If you think you will not have problems with unaligned
1918 accesses (for example because your toolchain prevents them)
1919 there is no need to set this option.
1921 CONFIG_SPLASH_SCREEN_ALIGN
1923 If this option is set the splash image can be freely positioned
1924 on the screen. Environment variable "splashpos" specifies the
1925 position as "x,y". If a positive number is given it is used as
1926 number of pixel from left/top. If a negative number is given it
1927 is used as number of pixel from right/bottom. You can also
1928 specify 'm' for centering the image.
1931 setenv splashpos m,m
1932 => image at center of screen
1934 setenv splashpos 30,20
1935 => image at x = 30 and y = 20
1937 setenv splashpos -10,m
1938 => vertically centered image
1939 at x = dspWidth - bmpWidth - 9
1941 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1943 If this option is set, additionally to standard BMP
1944 images, gzipped BMP images can be displayed via the
1945 splashscreen support or the bmp command.
1947 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1949 If this option is set, 8-bit RLE compressed BMP images
1950 can be displayed via the splashscreen support or the
1953 - Do compressing for memory range:
1956 If this option is set, it would use zlib deflate method
1957 to compress the specified memory at its best effort.
1959 - Compression support:
1962 Enabled by default to support gzip compressed images.
1966 If this option is set, support for bzip2 compressed
1967 images is included. If not, only uncompressed and gzip
1968 compressed images are supported.
1970 NOTE: the bzip2 algorithm requires a lot of RAM, so
1971 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1976 If this option is set, support for lzma compressed
1979 Note: The LZMA algorithm adds between 2 and 4KB of code and it
1980 requires an amount of dynamic memory that is given by the
1983 (1846 + 768 << (lc + lp)) * sizeof(uint16)
1985 Where lc and lp stand for, respectively, Literal context bits
1986 and Literal pos bits.
1988 This value is upper-bounded by 14MB in the worst case. Anyway,
1989 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
1990 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
1991 a very small buffer.
1993 Use the lzmainfo tool to determinate the lc and lp values and
1994 then calculate the amount of needed dynamic memory (ensuring
1995 the appropriate CONFIG_SYS_MALLOC_LEN value).
1999 If this option is set, support for LZO compressed images
2005 The address of PHY on MII bus.
2007 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
2009 The clock frequency of the MII bus
2013 If this option is set, support for speed/duplex
2014 detection of gigabit PHY is included.
2016 CONFIG_PHY_RESET_DELAY
2018 Some PHY like Intel LXT971A need extra delay after
2019 reset before any MII register access is possible.
2020 For such PHY, set this option to the usec delay
2021 required. (minimum 300usec for LXT971A)
2023 CONFIG_PHY_CMD_DELAY (ppc4xx)
2025 Some PHY like Intel LXT971A need extra delay after
2026 command issued before MII status register can be read
2031 Define a default value for the IP address to use for
2032 the default Ethernet interface, in case this is not
2033 determined through e.g. bootp.
2034 (Environment variable "ipaddr")
2036 - Server IP address:
2039 Defines a default value for the IP address of a TFTP
2040 server to contact when using the "tftboot" command.
2041 (Environment variable "serverip")
2043 CONFIG_KEEP_SERVERADDR
2045 Keeps the server's MAC address, in the env 'serveraddr'
2046 for passing to bootargs (like Linux's netconsole option)
2048 - Gateway IP address:
2051 Defines a default value for the IP address of the
2052 default router where packets to other networks are
2054 (Environment variable "gatewayip")
2059 Defines a default value for the subnet mask (or
2060 routing prefix) which is used to determine if an IP
2061 address belongs to the local subnet or needs to be
2062 forwarded through a router.
2063 (Environment variable "netmask")
2065 - Multicast TFTP Mode:
2068 Defines whether you want to support multicast TFTP as per
2069 rfc-2090; for example to work with atftp. Lets lots of targets
2070 tftp down the same boot image concurrently. Note: the Ethernet
2071 driver in use must provide a function: mcast() to join/leave a
2074 - BOOTP Recovery Mode:
2075 CONFIG_BOOTP_RANDOM_DELAY
2077 If you have many targets in a network that try to
2078 boot using BOOTP, you may want to avoid that all
2079 systems send out BOOTP requests at precisely the same
2080 moment (which would happen for instance at recovery
2081 from a power failure, when all systems will try to
2082 boot, thus flooding the BOOTP server. Defining
2083 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
2084 inserted before sending out BOOTP requests. The
2085 following delays are inserted then:
2087 1st BOOTP request: delay 0 ... 1 sec
2088 2nd BOOTP request: delay 0 ... 2 sec
2089 3rd BOOTP request: delay 0 ... 4 sec
2091 BOOTP requests: delay 0 ... 8 sec
2093 CONFIG_BOOTP_ID_CACHE_SIZE
2095 BOOTP packets are uniquely identified using a 32-bit ID. The
2096 server will copy the ID from client requests to responses and
2097 U-Boot will use this to determine if it is the destination of
2098 an incoming response. Some servers will check that addresses
2099 aren't in use before handing them out (usually using an ARP
2100 ping) and therefore take up to a few hundred milliseconds to
2101 respond. Network congestion may also influence the time it
2102 takes for a response to make it back to the client. If that
2103 time is too long, U-Boot will retransmit requests. In order
2104 to allow earlier responses to still be accepted after these
2105 retransmissions, U-Boot's BOOTP client keeps a small cache of
2106 IDs. The CONFIG_BOOTP_ID_CACHE_SIZE controls the size of this
2107 cache. The default is to keep IDs for up to four outstanding
2108 requests. Increasing this will allow U-Boot to accept offers
2109 from a BOOTP client in networks with unusually high latency.
2111 - DHCP Advanced Options:
2112 You can fine tune the DHCP functionality by defining
2113 CONFIG_BOOTP_* symbols:
2115 CONFIG_BOOTP_SUBNETMASK
2116 CONFIG_BOOTP_GATEWAY
2117 CONFIG_BOOTP_HOSTNAME
2118 CONFIG_BOOTP_NISDOMAIN
2119 CONFIG_BOOTP_BOOTPATH
2120 CONFIG_BOOTP_BOOTFILESIZE
2123 CONFIG_BOOTP_SEND_HOSTNAME
2124 CONFIG_BOOTP_NTPSERVER
2125 CONFIG_BOOTP_TIMEOFFSET
2126 CONFIG_BOOTP_VENDOREX
2127 CONFIG_BOOTP_MAY_FAIL
2129 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
2130 environment variable, not the BOOTP server.
2132 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
2133 after the configured retry count, the call will fail
2134 instead of starting over. This can be used to fail over
2135 to Link-local IP address configuration if the DHCP server
2138 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
2139 serverip from a DHCP server, it is possible that more
2140 than one DNS serverip is offered to the client.
2141 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
2142 serverip will be stored in the additional environment
2143 variable "dnsip2". The first DNS serverip is always
2144 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
2147 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
2148 to do a dynamic update of a DNS server. To do this, they
2149 need the hostname of the DHCP requester.
2150 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
2151 of the "hostname" environment variable is passed as
2152 option 12 to the DHCP server.
2154 CONFIG_BOOTP_DHCP_REQUEST_DELAY
2156 A 32bit value in microseconds for a delay between
2157 receiving a "DHCP Offer" and sending the "DHCP Request".
2158 This fixes a problem with certain DHCP servers that don't
2159 respond 100% of the time to a "DHCP request". E.g. On an
2160 AT91RM9200 processor running at 180MHz, this delay needed
2161 to be *at least* 15,000 usec before a Windows Server 2003
2162 DHCP server would reply 100% of the time. I recommend at
2163 least 50,000 usec to be safe. The alternative is to hope
2164 that one of the retries will be successful but note that
2165 the DHCP timeout and retry process takes a longer than
2168 - Link-local IP address negotiation:
2169 Negotiate with other link-local clients on the local network
2170 for an address that doesn't require explicit configuration.
2171 This is especially useful if a DHCP server cannot be guaranteed
2172 to exist in all environments that the device must operate.
2174 See doc/README.link-local for more information.
2177 CONFIG_CDP_DEVICE_ID
2179 The device id used in CDP trigger frames.
2181 CONFIG_CDP_DEVICE_ID_PREFIX
2183 A two character string which is prefixed to the MAC address
2188 A printf format string which contains the ascii name of
2189 the port. Normally is set to "eth%d" which sets
2190 eth0 for the first Ethernet, eth1 for the second etc.
2192 CONFIG_CDP_CAPABILITIES
2194 A 32bit integer which indicates the device capabilities;
2195 0x00000010 for a normal host which does not forwards.
2199 An ascii string containing the version of the software.
2203 An ascii string containing the name of the platform.
2207 A 32bit integer sent on the trigger.
2209 CONFIG_CDP_POWER_CONSUMPTION
2211 A 16bit integer containing the power consumption of the
2212 device in .1 of milliwatts.
2214 CONFIG_CDP_APPLIANCE_VLAN_TYPE
2216 A byte containing the id of the VLAN.
2218 - Status LED: CONFIG_STATUS_LED
2220 Several configurations allow to display the current
2221 status using a LED. For instance, the LED will blink
2222 fast while running U-Boot code, stop blinking as
2223 soon as a reply to a BOOTP request was received, and
2224 start blinking slow once the Linux kernel is running
2225 (supported by a status LED driver in the Linux
2226 kernel). Defining CONFIG_STATUS_LED enables this
2232 The status LED can be connected to a GPIO pin.
2233 In such cases, the gpio_led driver can be used as a
2234 status LED backend implementation. Define CONFIG_GPIO_LED
2235 to include the gpio_led driver in the U-Boot binary.
2237 CONFIG_GPIO_LED_INVERTED_TABLE
2238 Some GPIO connected LEDs may have inverted polarity in which
2239 case the GPIO high value corresponds to LED off state and
2240 GPIO low value corresponds to LED on state.
2241 In such cases CONFIG_GPIO_LED_INVERTED_TABLE may be defined
2242 with a list of GPIO LEDs that have inverted polarity.
2244 - CAN Support: CONFIG_CAN_DRIVER
2246 Defining CONFIG_CAN_DRIVER enables CAN driver support
2247 on those systems that support this (optional)
2248 feature, like the TQM8xxL modules.
2250 - I2C Support: CONFIG_SYS_I2C
2252 This enable the NEW i2c subsystem, and will allow you to use
2253 i2c commands at the u-boot command line (as long as you set
2254 CONFIG_CMD_I2C in CONFIG_COMMANDS) and communicate with i2c
2255 based realtime clock chips or other i2c devices. See
2256 common/cmd_i2c.c for a description of the command line
2259 ported i2c driver to the new framework:
2260 - drivers/i2c/soft_i2c.c:
2261 - activate first bus with CONFIG_SYS_I2C_SOFT define
2262 CONFIG_SYS_I2C_SOFT_SPEED and CONFIG_SYS_I2C_SOFT_SLAVE
2263 for defining speed and slave address
2264 - activate second bus with I2C_SOFT_DECLARATIONS2 define
2265 CONFIG_SYS_I2C_SOFT_SPEED_2 and CONFIG_SYS_I2C_SOFT_SLAVE_2
2266 for defining speed and slave address
2267 - activate third bus with I2C_SOFT_DECLARATIONS3 define
2268 CONFIG_SYS_I2C_SOFT_SPEED_3 and CONFIG_SYS_I2C_SOFT_SLAVE_3
2269 for defining speed and slave address
2270 - activate fourth bus with I2C_SOFT_DECLARATIONS4 define
2271 CONFIG_SYS_I2C_SOFT_SPEED_4 and CONFIG_SYS_I2C_SOFT_SLAVE_4
2272 for defining speed and slave address
2274 - drivers/i2c/fsl_i2c.c:
2275 - activate i2c driver with CONFIG_SYS_I2C_FSL
2276 define CONFIG_SYS_FSL_I2C_OFFSET for setting the register
2277 offset CONFIG_SYS_FSL_I2C_SPEED for the i2c speed and
2278 CONFIG_SYS_FSL_I2C_SLAVE for the slave addr of the first
2280 - If your board supports a second fsl i2c bus, define
2281 CONFIG_SYS_FSL_I2C2_OFFSET for the register offset
2282 CONFIG_SYS_FSL_I2C2_SPEED for the speed and
2283 CONFIG_SYS_FSL_I2C2_SLAVE for the slave address of the
2286 - drivers/i2c/tegra_i2c.c:
2287 - activate this driver with CONFIG_SYS_I2C_TEGRA
2288 - This driver adds 4 i2c buses with a fix speed from
2289 100000 and the slave addr 0!
2291 - drivers/i2c/ppc4xx_i2c.c
2292 - activate this driver with CONFIG_SYS_I2C_PPC4XX
2293 - CONFIG_SYS_I2C_PPC4XX_CH0 activate hardware channel 0
2294 - CONFIG_SYS_I2C_PPC4XX_CH1 activate hardware channel 1
2296 - drivers/i2c/i2c_mxc.c
2297 - activate this driver with CONFIG_SYS_I2C_MXC
2298 - enable bus 1 with CONFIG_SYS_I2C_MXC_I2C1
2299 - enable bus 2 with CONFIG_SYS_I2C_MXC_I2C2
2300 - enable bus 3 with CONFIG_SYS_I2C_MXC_I2C3
2301 - enable bus 4 with CONFIG_SYS_I2C_MXC_I2C4
2302 - define speed for bus 1 with CONFIG_SYS_MXC_I2C1_SPEED
2303 - define slave for bus 1 with CONFIG_SYS_MXC_I2C1_SLAVE
2304 - define speed for bus 2 with CONFIG_SYS_MXC_I2C2_SPEED
2305 - define slave for bus 2 with CONFIG_SYS_MXC_I2C2_SLAVE
2306 - define speed for bus 3 with CONFIG_SYS_MXC_I2C3_SPEED
2307 - define slave for bus 3 with CONFIG_SYS_MXC_I2C3_SLAVE
2308 - define speed for bus 4 with CONFIG_SYS_MXC_I2C4_SPEED
2309 - define slave for bus 4 with CONFIG_SYS_MXC_I2C4_SLAVE
2310 If those defines are not set, default value is 100000
2311 for speed, and 0 for slave.
2313 - drivers/i2c/rcar_i2c.c:
2314 - activate this driver with CONFIG_SYS_I2C_RCAR
2315 - This driver adds 4 i2c buses
2317 - CONFIG_SYS_RCAR_I2C0_BASE for setting the register channel 0
2318 - CONFIG_SYS_RCAR_I2C0_SPEED for for the speed channel 0
2319 - CONFIG_SYS_RCAR_I2C1_BASE for setting the register channel 1
2320 - CONFIG_SYS_RCAR_I2C1_SPEED for for the speed channel 1
2321 - CONFIG_SYS_RCAR_I2C2_BASE for setting the register channel 2
2322 - CONFIG_SYS_RCAR_I2C2_SPEED for for the speed channel 2
2323 - CONFIG_SYS_RCAR_I2C3_BASE for setting the register channel 3
2324 - CONFIG_SYS_RCAR_I2C3_SPEED for for the speed channel 3
2325 - CONFIF_SYS_RCAR_I2C_NUM_CONTROLLERS for number of i2c buses
2327 - drivers/i2c/sh_i2c.c:
2328 - activate this driver with CONFIG_SYS_I2C_SH
2329 - This driver adds from 2 to 5 i2c buses
2331 - CONFIG_SYS_I2C_SH_BASE0 for setting the register channel 0
2332 - CONFIG_SYS_I2C_SH_SPEED0 for for the speed channel 0
2333 - CONFIG_SYS_I2C_SH_BASE1 for setting the register channel 1
2334 - CONFIG_SYS_I2C_SH_SPEED1 for for the speed channel 1
2335 - CONFIG_SYS_I2C_SH_BASE2 for setting the register channel 2
2336 - CONFIG_SYS_I2C_SH_SPEED2 for for the speed channel 2
2337 - CONFIG_SYS_I2C_SH_BASE3 for setting the register channel 3
2338 - CONFIG_SYS_I2C_SH_SPEED3 for for the speed channel 3
2339 - CONFIG_SYS_I2C_SH_BASE4 for setting the register channel 4
2340 - CONFIG_SYS_I2C_SH_SPEED4 for for the speed channel 4
2341 - CONFIG_SYS_I2C_SH_BASE5 for setting the register channel 5
2342 - CONFIG_SYS_I2C_SH_SPEED5 for for the speed channel 5
2343 - CONFIG_SYS_I2C_SH_NUM_CONTROLLERS for number of i2c buses
2345 - drivers/i2c/omap24xx_i2c.c
2346 - activate this driver with CONFIG_SYS_I2C_OMAP24XX
2347 - CONFIG_SYS_OMAP24_I2C_SPEED speed channel 0
2348 - CONFIG_SYS_OMAP24_I2C_SLAVE slave addr channel 0
2349 - CONFIG_SYS_OMAP24_I2C_SPEED1 speed channel 1
2350 - CONFIG_SYS_OMAP24_I2C_SLAVE1 slave addr channel 1
2351 - CONFIG_SYS_OMAP24_I2C_SPEED2 speed channel 2
2352 - CONFIG_SYS_OMAP24_I2C_SLAVE2 slave addr channel 2
2353 - CONFIG_SYS_OMAP24_I2C_SPEED3 speed channel 3
2354 - CONFIG_SYS_OMAP24_I2C_SLAVE3 slave addr channel 3
2355 - CONFIG_SYS_OMAP24_I2C_SPEED4 speed channel 4
2356 - CONFIG_SYS_OMAP24_I2C_SLAVE4 slave addr channel 4
2358 - drivers/i2c/zynq_i2c.c
2359 - activate this driver with CONFIG_SYS_I2C_ZYNQ
2360 - set CONFIG_SYS_I2C_ZYNQ_SPEED for speed setting
2361 - set CONFIG_SYS_I2C_ZYNQ_SLAVE for slave addr
2363 - drivers/i2c/s3c24x0_i2c.c:
2364 - activate this driver with CONFIG_SYS_I2C_S3C24X0
2365 - This driver adds i2c buses (11 for Exynos5250, Exynos5420
2366 9 i2c buses for Exynos4 and 1 for S3C24X0 SoCs from Samsung)
2367 with a fix speed from 100000 and the slave addr 0!
2369 - drivers/i2c/ihs_i2c.c
2370 - activate this driver with CONFIG_SYS_I2C_IHS
2371 - CONFIG_SYS_I2C_IHS_CH0 activate hardware channel 0
2372 - CONFIG_SYS_I2C_IHS_SPEED_0 speed channel 0
2373 - CONFIG_SYS_I2C_IHS_SLAVE_0 slave addr channel 0
2374 - CONFIG_SYS_I2C_IHS_CH1 activate hardware channel 1
2375 - CONFIG_SYS_I2C_IHS_SPEED_1 speed channel 1
2376 - CONFIG_SYS_I2C_IHS_SLAVE_1 slave addr channel 1
2377 - CONFIG_SYS_I2C_IHS_CH2 activate hardware channel 2
2378 - CONFIG_SYS_I2C_IHS_SPEED_2 speed channel 2
2379 - CONFIG_SYS_I2C_IHS_SLAVE_2 slave addr channel 2
2380 - CONFIG_SYS_I2C_IHS_CH3 activate hardware channel 3
2381 - CONFIG_SYS_I2C_IHS_SPEED_3 speed channel 3
2382 - CONFIG_SYS_I2C_IHS_SLAVE_3 slave addr channel 3
2383 - activate dual channel with CONFIG_SYS_I2C_IHS_DUAL
2384 - CONFIG_SYS_I2C_IHS_SPEED_0_1 speed channel 0_1
2385 - CONFIG_SYS_I2C_IHS_SLAVE_0_1 slave addr channel 0_1
2386 - CONFIG_SYS_I2C_IHS_SPEED_1_1 speed channel 1_1
2387 - CONFIG_SYS_I2C_IHS_SLAVE_1_1 slave addr channel 1_1
2388 - CONFIG_SYS_I2C_IHS_SPEED_2_1 speed channel 2_1
2389 - CONFIG_SYS_I2C_IHS_SLAVE_2_1 slave addr channel 2_1
2390 - CONFIG_SYS_I2C_IHS_SPEED_3_1 speed channel 3_1
2391 - CONFIG_SYS_I2C_IHS_SLAVE_3_1 slave addr channel 3_1
2395 CONFIG_SYS_NUM_I2C_BUSES
2396 Hold the number of i2c buses you want to use. If you
2397 don't use/have i2c muxes on your i2c bus, this
2398 is equal to CONFIG_SYS_NUM_I2C_ADAPTERS, and you can
2401 CONFIG_SYS_I2C_DIRECT_BUS
2402 define this, if you don't use i2c muxes on your hardware.
2403 if CONFIG_SYS_I2C_MAX_HOPS is not defined or == 0 you can
2406 CONFIG_SYS_I2C_MAX_HOPS
2407 define how many muxes are maximal consecutively connected
2408 on one i2c bus. If you not use i2c muxes, omit this
2411 CONFIG_SYS_I2C_BUSES
2412 hold a list of buses you want to use, only used if
2413 CONFIG_SYS_I2C_DIRECT_BUS is not defined, for example
2414 a board with CONFIG_SYS_I2C_MAX_HOPS = 1 and
2415 CONFIG_SYS_NUM_I2C_BUSES = 9:
2417 CONFIG_SYS_I2C_BUSES {{0, {I2C_NULL_HOP}}, \
2418 {0, {{I2C_MUX_PCA9547, 0x70, 1}}}, \
2419 {0, {{I2C_MUX_PCA9547, 0x70, 2}}}, \
2420 {0, {{I2C_MUX_PCA9547, 0x70, 3}}}, \
2421 {0, {{I2C_MUX_PCA9547, 0x70, 4}}}, \
2422 {0, {{I2C_MUX_PCA9547, 0x70, 5}}}, \
2423 {1, {I2C_NULL_HOP}}, \
2424 {1, {{I2C_MUX_PCA9544, 0x72, 1}}}, \
2425 {1, {{I2C_MUX_PCA9544, 0x72, 2}}}, \
2429 bus 0 on adapter 0 without a mux
2430 bus 1 on adapter 0 with a PCA9547 on address 0x70 port 1
2431 bus 2 on adapter 0 with a PCA9547 on address 0x70 port 2
2432 bus 3 on adapter 0 with a PCA9547 on address 0x70 port 3
2433 bus 4 on adapter 0 with a PCA9547 on address 0x70 port 4
2434 bus 5 on adapter 0 with a PCA9547 on address 0x70 port 5
2435 bus 6 on adapter 1 without a mux
2436 bus 7 on adapter 1 with a PCA9544 on address 0x72 port 1
2437 bus 8 on adapter 1 with a PCA9544 on address 0x72 port 2
2439 If you do not have i2c muxes on your board, omit this define.
2441 - Legacy I2C Support: CONFIG_HARD_I2C
2443 NOTE: It is intended to move drivers to CONFIG_SYS_I2C which
2444 provides the following compelling advantages:
2446 - more than one i2c adapter is usable
2447 - approved multibus support
2448 - better i2c mux support
2450 ** Please consider updating your I2C driver now. **
2452 These enable legacy I2C serial bus commands. Defining
2453 CONFIG_HARD_I2C will include the appropriate I2C driver
2454 for the selected CPU.
2456 This will allow you to use i2c commands at the u-boot
2457 command line (as long as you set CONFIG_CMD_I2C in
2458 CONFIG_COMMANDS) and communicate with i2c based realtime
2459 clock chips. See common/cmd_i2c.c for a description of the
2460 command line interface.
2462 CONFIG_HARD_I2C selects a hardware I2C controller.
2464 There are several other quantities that must also be
2465 defined when you define CONFIG_HARD_I2C.
2467 In both cases you will need to define CONFIG_SYS_I2C_SPEED
2468 to be the frequency (in Hz) at which you wish your i2c bus
2469 to run and CONFIG_SYS_I2C_SLAVE to be the address of this node (ie
2470 the CPU's i2c node address).
2472 Now, the u-boot i2c code for the mpc8xx
2473 (arch/powerpc/cpu/mpc8xx/i2c.c) sets the CPU up as a master node
2474 and so its address should therefore be cleared to 0 (See,
2475 eg, MPC823e User's Manual p.16-473). So, set
2476 CONFIG_SYS_I2C_SLAVE to 0.
2478 CONFIG_SYS_I2C_INIT_MPC5XXX
2480 When a board is reset during an i2c bus transfer
2481 chips might think that the current transfer is still
2482 in progress. Reset the slave devices by sending start
2483 commands until the slave device responds.
2485 That's all that's required for CONFIG_HARD_I2C.
2487 If you use the software i2c interface (CONFIG_SYS_I2C_SOFT)
2488 then the following macros need to be defined (examples are
2489 from include/configs/lwmon.h):
2493 (Optional). Any commands necessary to enable the I2C
2494 controller or configure ports.
2496 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
2500 (Only for MPC8260 CPU). The I/O port to use (the code
2501 assumes both bits are on the same port). Valid values
2502 are 0..3 for ports A..D.
2506 The code necessary to make the I2C data line active
2507 (driven). If the data line is open collector, this
2510 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
2514 The code necessary to make the I2C data line tri-stated
2515 (inactive). If the data line is open collector, this
2518 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
2522 Code that returns true if the I2C data line is high,
2525 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
2529 If <bit> is true, sets the I2C data line high. If it
2530 is false, it clears it (low).
2532 eg: #define I2C_SDA(bit) \
2533 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
2534 else immr->im_cpm.cp_pbdat &= ~PB_SDA
2538 If <bit> is true, sets the I2C clock line high. If it
2539 is false, it clears it (low).
2541 eg: #define I2C_SCL(bit) \
2542 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
2543 else immr->im_cpm.cp_pbdat &= ~PB_SCL
2547 This delay is invoked four times per clock cycle so this
2548 controls the rate of data transfer. The data rate thus
2549 is 1 / (I2C_DELAY * 4). Often defined to be something
2552 #define I2C_DELAY udelay(2)
2554 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
2556 If your arch supports the generic GPIO framework (asm/gpio.h),
2557 then you may alternatively define the two GPIOs that are to be
2558 used as SCL / SDA. Any of the previous I2C_xxx macros will
2559 have GPIO-based defaults assigned to them as appropriate.
2561 You should define these to the GPIO value as given directly to
2562 the generic GPIO functions.
2564 CONFIG_SYS_I2C_INIT_BOARD
2566 When a board is reset during an i2c bus transfer
2567 chips might think that the current transfer is still
2568 in progress. On some boards it is possible to access
2569 the i2c SCLK line directly, either by using the
2570 processor pin as a GPIO or by having a second pin
2571 connected to the bus. If this option is defined a
2572 custom i2c_init_board() routine in boards/xxx/board.c
2573 is run early in the boot sequence.
2575 CONFIG_SYS_I2C_BOARD_LATE_INIT
2577 An alternative to CONFIG_SYS_I2C_INIT_BOARD. If this option is
2578 defined a custom i2c_board_late_init() routine in
2579 boards/xxx/board.c is run AFTER the operations in i2c_init()
2580 is completed. This callpoint can be used to unreset i2c bus
2581 using CPU i2c controller register accesses for CPUs whose i2c
2582 controller provide such a method. It is called at the end of
2583 i2c_init() to allow i2c_init operations to setup the i2c bus
2584 controller on the CPU (e.g. setting bus speed & slave address).
2586 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
2588 This option enables configuration of bi_iic_fast[] flags
2589 in u-boot bd_info structure based on u-boot environment
2590 variable "i2cfast". (see also i2cfast)
2592 CONFIG_I2C_MULTI_BUS
2594 This option allows the use of multiple I2C buses, each of which
2595 must have a controller. At any point in time, only one bus is
2596 active. To switch to a different bus, use the 'i2c dev' command.
2597 Note that bus numbering is zero-based.
2599 CONFIG_SYS_I2C_NOPROBES
2601 This option specifies a list of I2C devices that will be skipped
2602 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
2603 is set, specify a list of bus-device pairs. Otherwise, specify
2604 a 1D array of device addresses
2607 #undef CONFIG_I2C_MULTI_BUS
2608 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
2610 will skip addresses 0x50 and 0x68 on a board with one I2C bus
2612 #define CONFIG_I2C_MULTI_BUS
2613 #define CONFIG_SYS_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
2615 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
2617 CONFIG_SYS_SPD_BUS_NUM
2619 If defined, then this indicates the I2C bus number for DDR SPD.
2620 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
2622 CONFIG_SYS_RTC_BUS_NUM
2624 If defined, then this indicates the I2C bus number for the RTC.
2625 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
2627 CONFIG_SYS_DTT_BUS_NUM
2629 If defined, then this indicates the I2C bus number for the DTT.
2630 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
2632 CONFIG_SYS_I2C_DTT_ADDR:
2634 If defined, specifies the I2C address of the DTT device.
2635 If not defined, then U-Boot uses predefined value for
2636 specified DTT device.
2638 CONFIG_SOFT_I2C_READ_REPEATED_START
2640 defining this will force the i2c_read() function in
2641 the soft_i2c driver to perform an I2C repeated start
2642 between writing the address pointer and reading the
2643 data. If this define is omitted the default behaviour
2644 of doing a stop-start sequence will be used. Most I2C
2645 devices can use either method, but some require one or
2648 - SPI Support: CONFIG_SPI
2650 Enables SPI driver (so far only tested with
2651 SPI EEPROM, also an instance works with Crystal A/D and
2652 D/As on the SACSng board)
2656 Enables the driver for SPI controller on SuperH. Currently
2657 only SH7757 is supported.
2661 Enables a software (bit-bang) SPI driver rather than
2662 using hardware support. This is a general purpose
2663 driver that only requires three general I/O port pins
2664 (two outputs, one input) to function. If this is
2665 defined, the board configuration must define several
2666 SPI configuration items (port pins to use, etc). For
2667 an example, see include/configs/sacsng.h.
2671 Enables a hardware SPI driver for general-purpose reads
2672 and writes. As with CONFIG_SOFT_SPI, the board configuration
2673 must define a list of chip-select function pointers.
2674 Currently supported on some MPC8xxx processors. For an
2675 example, see include/configs/mpc8349emds.h.
2679 Enables the driver for the SPI controllers on i.MX and MXC
2680 SoCs. Currently i.MX31/35/51 are supported.
2682 CONFIG_SYS_SPI_MXC_WAIT
2683 Timeout for waiting until spi transfer completed.
2684 default: (CONFIG_SYS_HZ/100) /* 10 ms */
2686 - FPGA Support: CONFIG_FPGA
2688 Enables FPGA subsystem.
2690 CONFIG_FPGA_<vendor>
2692 Enables support for specific chip vendors.
2695 CONFIG_FPGA_<family>
2697 Enables support for FPGA family.
2698 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
2702 Specify the number of FPGA devices to support.
2704 CONFIG_CMD_FPGA_LOADMK
2706 Enable support for fpga loadmk command
2708 CONFIG_CMD_FPGA_LOADP
2710 Enable support for fpga loadp command - load partial bitstream
2712 CONFIG_CMD_FPGA_LOADBP
2714 Enable support for fpga loadbp command - load partial bitstream
2717 CONFIG_SYS_FPGA_PROG_FEEDBACK
2719 Enable printing of hash marks during FPGA configuration.
2721 CONFIG_SYS_FPGA_CHECK_BUSY
2723 Enable checks on FPGA configuration interface busy
2724 status by the configuration function. This option
2725 will require a board or device specific function to
2730 If defined, a function that provides delays in the FPGA
2731 configuration driver.
2733 CONFIG_SYS_FPGA_CHECK_CTRLC
2734 Allow Control-C to interrupt FPGA configuration
2736 CONFIG_SYS_FPGA_CHECK_ERROR
2738 Check for configuration errors during FPGA bitfile
2739 loading. For example, abort during Virtex II
2740 configuration if the INIT_B line goes low (which
2741 indicated a CRC error).
2743 CONFIG_SYS_FPGA_WAIT_INIT
2745 Maximum time to wait for the INIT_B line to de-assert
2746 after PROB_B has been de-asserted during a Virtex II
2747 FPGA configuration sequence. The default time is 500
2750 CONFIG_SYS_FPGA_WAIT_BUSY
2752 Maximum time to wait for BUSY to de-assert during
2753 Virtex II FPGA configuration. The default is 5 ms.
2755 CONFIG_SYS_FPGA_WAIT_CONFIG
2757 Time to wait after FPGA configuration. The default is
2760 - Configuration Management:
2763 Some SoCs need special image types (e.g. U-Boot binary
2764 with a special header) as build targets. By defining
2765 CONFIG_BUILD_TARGET in the SoC / board header, this
2766 special image will be automatically built upon calling
2771 If defined, this string will be added to the U-Boot
2772 version information (U_BOOT_VERSION)
2774 - Vendor Parameter Protection:
2776 U-Boot considers the values of the environment
2777 variables "serial#" (Board Serial Number) and
2778 "ethaddr" (Ethernet Address) to be parameters that
2779 are set once by the board vendor / manufacturer, and
2780 protects these variables from casual modification by
2781 the user. Once set, these variables are read-only,
2782 and write or delete attempts are rejected. You can
2783 change this behaviour:
2785 If CONFIG_ENV_OVERWRITE is #defined in your config
2786 file, the write protection for vendor parameters is
2787 completely disabled. Anybody can change or delete
2790 Alternatively, if you define _both_ an ethaddr in the
2791 default env _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2792 Ethernet address is installed in the environment,
2793 which can be changed exactly ONCE by the user. [The
2794 serial# is unaffected by this, i. e. it remains
2797 The same can be accomplished in a more flexible way
2798 for any variable by configuring the type of access
2799 to allow for those variables in the ".flags" variable
2800 or define CONFIG_ENV_FLAGS_LIST_STATIC.
2805 Define this variable to enable the reservation of
2806 "protected RAM", i. e. RAM which is not overwritten
2807 by U-Boot. Define CONFIG_PRAM to hold the number of
2808 kB you want to reserve for pRAM. You can overwrite
2809 this default value by defining an environment
2810 variable "pram" to the number of kB you want to
2811 reserve. Note that the board info structure will
2812 still show the full amount of RAM. If pRAM is
2813 reserved, a new environment variable "mem" will
2814 automatically be defined to hold the amount of
2815 remaining RAM in a form that can be passed as boot
2816 argument to Linux, for instance like that:
2818 setenv bootargs ... mem=\${mem}
2821 This way you can tell Linux not to use this memory,
2822 either, which results in a memory region that will
2823 not be affected by reboots.
2825 *WARNING* If your board configuration uses automatic
2826 detection of the RAM size, you must make sure that
2827 this memory test is non-destructive. So far, the
2828 following board configurations are known to be
2831 IVMS8, IVML24, SPD8xx, TQM8xxL,
2832 HERMES, IP860, RPXlite, LWMON,
2835 - Access to physical memory region (> 4GB)
2836 Some basic support is provided for operations on memory not
2837 normally accessible to U-Boot - e.g. some architectures
2838 support access to more than 4GB of memory on 32-bit
2839 machines using physical address extension or similar.
2840 Define CONFIG_PHYSMEM to access this basic support, which
2841 currently only supports clearing the memory.
2846 Define this variable to stop the system in case of a
2847 fatal error, so that you have to reset it manually.
2848 This is probably NOT a good idea for an embedded
2849 system where you want the system to reboot
2850 automatically as fast as possible, but it may be
2851 useful during development since you can try to debug
2852 the conditions that lead to the situation.
2854 CONFIG_NET_RETRY_COUNT
2856 This variable defines the number of retries for
2857 network operations like ARP, RARP, TFTP, or BOOTP
2858 before giving up the operation. If not defined, a
2859 default value of 5 is used.
2863 Timeout waiting for an ARP reply in milliseconds.
2867 Timeout in milliseconds used in NFS protocol.
2868 If you encounter "ERROR: Cannot umount" in nfs command,
2869 try longer timeout such as
2870 #define CONFIG_NFS_TIMEOUT 10000UL
2872 - Command Interpreter:
2873 CONFIG_AUTO_COMPLETE
2875 Enable auto completion of commands using TAB.
2877 CONFIG_SYS_PROMPT_HUSH_PS2
2879 This defines the secondary prompt string, which is
2880 printed when the command interpreter needs more input
2881 to complete a command. Usually "> ".
2885 In the current implementation, the local variables
2886 space and global environment variables space are
2887 separated. Local variables are those you define by
2888 simply typing `name=value'. To access a local
2889 variable later on, you have write `$name' or
2890 `${name}'; to execute the contents of a variable
2891 directly type `$name' at the command prompt.
2893 Global environment variables are those you use
2894 setenv/printenv to work with. To run a command stored
2895 in such a variable, you need to use the run command,
2896 and you must not use the '$' sign to access them.
2898 To store commands and special characters in a
2899 variable, please use double quotation marks
2900 surrounding the whole text of the variable, instead
2901 of the backslashes before semicolons and special
2904 - Command Line Editing and History:
2905 CONFIG_CMDLINE_EDITING
2907 Enable editing and History functions for interactive
2908 command line input operations
2910 - Command Line PS1/PS2 support:
2911 CONFIG_CMDLINE_PS_SUPPORT
2913 Enable support for changing the command prompt string
2914 at run-time. Only static string is supported so far.
2915 The string is obtained from environment variables PS1
2918 - Default Environment:
2919 CONFIG_EXTRA_ENV_SETTINGS
2921 Define this to contain any number of null terminated
2922 strings (variable = value pairs) that will be part of
2923 the default environment compiled into the boot image.
2925 For example, place something like this in your
2926 board's config file:
2928 #define CONFIG_EXTRA_ENV_SETTINGS \
2932 Warning: This method is based on knowledge about the
2933 internal format how the environment is stored by the
2934 U-Boot code. This is NOT an official, exported
2935 interface! Although it is unlikely that this format
2936 will change soon, there is no guarantee either.
2937 You better know what you are doing here.
2939 Note: overly (ab)use of the default environment is
2940 discouraged. Make sure to check other ways to preset
2941 the environment like the "source" command or the
2944 CONFIG_ENV_VARS_UBOOT_CONFIG
2946 Define this in order to add variables describing the
2947 U-Boot build configuration to the default environment.
2948 These will be named arch, cpu, board, vendor, and soc.
2950 Enabling this option will cause the following to be defined:
2958 CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG
2960 Define this in order to add variables describing certain
2961 run-time determined information about the hardware to the
2962 environment. These will be named board_name, board_rev.
2964 CONFIG_DELAY_ENVIRONMENT
2966 Normally the environment is loaded when the board is
2967 initialised so that it is available to U-Boot. This inhibits
2968 that so that the environment is not available until
2969 explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL
2970 this is instead controlled by the value of
2971 /config/load-environment.
2973 - Parallel Flash support:
2976 Traditionally U-Boot was run on systems with parallel NOR
2977 flash. This option is used to disable support for parallel NOR
2978 flash. This option should be defined if the board does not have
2981 If this option is not defined one of the generic flash drivers
2982 (e.g. CONFIG_FLASH_CFI_DRIVER or CONFIG_ST_SMI) must be
2983 selected or the board must provide an implementation of the
2984 flash API (see include/flash.h).
2986 - DataFlash Support:
2987 CONFIG_HAS_DATAFLASH
2989 Defining this option enables DataFlash features and
2990 allows to read/write in Dataflash via the standard
2993 - Serial Flash support
2996 Defining this option enables SPI flash commands
2997 'sf probe/read/write/erase/update'.
2999 Usage requires an initial 'probe' to define the serial
3000 flash parameters, followed by read/write/erase/update
3003 The following defaults may be provided by the platform
3004 to handle the common case when only a single serial
3005 flash is present on the system.
3007 CONFIG_SF_DEFAULT_BUS Bus identifier
3008 CONFIG_SF_DEFAULT_CS Chip-select
3009 CONFIG_SF_DEFAULT_MODE (see include/spi.h)
3010 CONFIG_SF_DEFAULT_SPEED in Hz
3014 Define this option to include a destructive SPI flash
3017 CONFIG_SF_DUAL_FLASH Dual flash memories
3019 Define this option to use dual flash support where two flash
3020 memories can be connected with a given cs line.
3021 Currently Xilinx Zynq qspi supports these type of connections.
3023 - SystemACE Support:
3026 Adding this option adds support for Xilinx SystemACE
3027 chips attached via some sort of local bus. The address
3028 of the chip must also be defined in the
3029 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
3031 #define CONFIG_SYSTEMACE
3032 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
3034 When SystemACE support is added, the "ace" device type
3035 becomes available to the fat commands, i.e. fatls.
3037 - TFTP Fixed UDP Port:
3040 If this is defined, the environment variable tftpsrcp
3041 is used to supply the TFTP UDP source port value.
3042 If tftpsrcp isn't defined, the normal pseudo-random port
3043 number generator is used.
3045 Also, the environment variable tftpdstp is used to supply
3046 the TFTP UDP destination port value. If tftpdstp isn't
3047 defined, the normal port 69 is used.
3049 The purpose for tftpsrcp is to allow a TFTP server to
3050 blindly start the TFTP transfer using the pre-configured
3051 target IP address and UDP port. This has the effect of
3052 "punching through" the (Windows XP) firewall, allowing
3053 the remainder of the TFTP transfer to proceed normally.
3054 A better solution is to properly configure the firewall,
3055 but sometimes that is not allowed.
3060 This enables a generic 'hash' command which can produce
3061 hashes / digests from a few algorithms (e.g. SHA1, SHA256).
3065 Enable the hash verify command (hash -v). This adds to code
3068 CONFIG_SHA1 - This option enables support of hashing using SHA1
3069 algorithm. The hash is calculated in software.
3070 CONFIG_SHA256 - This option enables support of hashing using
3071 SHA256 algorithm. The hash is calculated in software.
3072 CONFIG_SHA_HW_ACCEL - This option enables hardware acceleration
3073 for SHA1/SHA256 hashing.
3074 This affects the 'hash' command and also the
3075 hash_lookup_algo() function.
3076 CONFIG_SHA_PROG_HW_ACCEL - This option enables
3077 hardware-acceleration for SHA1/SHA256 progressive hashing.
3078 Data can be streamed in a block at a time and the hashing
3079 is performed in hardware.
3081 Note: There is also a sha1sum command, which should perhaps
3082 be deprecated in favour of 'hash sha1'.
3084 - Freescale i.MX specific commands:
3085 CONFIG_CMD_HDMIDETECT
3086 This enables 'hdmidet' command which returns true if an
3087 HDMI monitor is detected. This command is i.MX 6 specific.
3090 This enables the 'bmode' (bootmode) command for forcing
3091 a boot from specific media.
3093 This is useful for forcing the ROM's usb downloader to
3094 activate upon a watchdog reset which is nice when iterating
3095 on U-Boot. Using the reset button or running bmode normal
3096 will set it back to normal. This command currently
3097 supports i.MX53 and i.MX6.
3099 - bootcount support:
3100 CONFIG_BOOTCOUNT_LIMIT
3102 This enables the bootcounter support, see:
3103 http://www.denx.de/wiki/DULG/UBootBootCountLimit
3106 enable special bootcounter support on at91sam9xe based boards.
3108 enable special bootcounter support on blackfin based boards.
3110 enable special bootcounter support on da850 based boards.
3111 CONFIG_BOOTCOUNT_RAM
3112 enable support for the bootcounter in RAM
3113 CONFIG_BOOTCOUNT_I2C
3114 enable support for the bootcounter on an i2c (like RTC) device.
3115 CONFIG_SYS_I2C_RTC_ADDR = i2c chip address
3116 CONFIG_SYS_BOOTCOUNT_ADDR = i2c addr which is used for
3118 CONFIG_BOOTCOUNT_ALEN = address len
3120 - Show boot progress:
3121 CONFIG_SHOW_BOOT_PROGRESS
3123 Defining this option allows to add some board-
3124 specific code (calling a user-provided function
3125 "show_boot_progress(int)") that enables you to show
3126 the system's boot progress on some display (for
3127 example, some LED's) on your board. At the moment,
3128 the following checkpoints are implemented:
3131 Legacy uImage format:
3134 1 common/cmd_bootm.c before attempting to boot an image
3135 -1 common/cmd_bootm.c Image header has bad magic number
3136 2 common/cmd_bootm.c Image header has correct magic number
3137 -2 common/cmd_bootm.c Image header has bad checksum
3138 3 common/cmd_bootm.c Image header has correct checksum
3139 -3 common/cmd_bootm.c Image data has bad checksum
3140 4 common/cmd_bootm.c Image data has correct checksum
3141 -4 common/cmd_bootm.c Image is for unsupported architecture
3142 5 common/cmd_bootm.c Architecture check OK
3143 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
3144 6 common/cmd_bootm.c Image Type check OK
3145 -6 common/cmd_bootm.c gunzip uncompression error
3146 -7 common/cmd_bootm.c Unimplemented compression type
3147 7 common/cmd_bootm.c Uncompression OK
3148 8 common/cmd_bootm.c No uncompress/copy overwrite error
3149 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
3151 9 common/image.c Start initial ramdisk verification
3152 -10 common/image.c Ramdisk header has bad magic number
3153 -11 common/image.c Ramdisk header has bad checksum
3154 10 common/image.c Ramdisk header is OK
3155 -12 common/image.c Ramdisk data has bad checksum
3156 11 common/image.c Ramdisk data has correct checksum
3157 12 common/image.c Ramdisk verification complete, start loading
3158 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
3159 13 common/image.c Start multifile image verification
3160 14 common/image.c No initial ramdisk, no multifile, continue.
3162 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
3164 -30 arch/powerpc/lib/board.c Fatal error, hang the system
3165 -31 post/post.c POST test failed, detected by post_output_backlog()
3166 -32 post/post.c POST test failed, detected by post_run_single()
3168 34 common/cmd_doc.c before loading a Image from a DOC device
3169 -35 common/cmd_doc.c Bad usage of "doc" command
3170 35 common/cmd_doc.c correct usage of "doc" command
3171 -36 common/cmd_doc.c No boot device
3172 36 common/cmd_doc.c correct boot device
3173 -37 common/cmd_doc.c Unknown Chip ID on boot device
3174 37 common/cmd_doc.c correct chip ID found, device available
3175 -38 common/cmd_doc.c Read Error on boot device
3176 38 common/cmd_doc.c reading Image header from DOC device OK
3177 -39 common/cmd_doc.c Image header has bad magic number
3178 39 common/cmd_doc.c Image header has correct magic number
3179 -40 common/cmd_doc.c Error reading Image from DOC device
3180 40 common/cmd_doc.c Image header has correct magic number
3181 41 common/cmd_ide.c before loading a Image from a IDE device
3182 -42 common/cmd_ide.c Bad usage of "ide" command
3183 42 common/cmd_ide.c correct usage of "ide" command
3184 -43 common/cmd_ide.c No boot device
3185 43 common/cmd_ide.c boot device found
3186 -44 common/cmd_ide.c Device not available
3187 44 common/cmd_ide.c Device available
3188 -45 common/cmd_ide.c wrong partition selected
3189 45 common/cmd_ide.c partition selected
3190 -46 common/cmd_ide.c Unknown partition table
3191 46 common/cmd_ide.c valid partition table found
3192 -47 common/cmd_ide.c Invalid partition type
3193 47 common/cmd_ide.c correct partition type
3194 -48 common/cmd_ide.c Error reading Image Header on boot device
3195 48 common/cmd_ide.c reading Image Header from IDE device OK
3196 -49 common/cmd_ide.c Image header has bad magic number
3197 49 common/cmd_ide.c Image header has correct magic number
3198 -50 common/cmd_ide.c Image header has bad checksum
3199 50 common/cmd_ide.c Image header has correct checksum
3200 -51 common/cmd_ide.c Error reading Image from IDE device
3201 51 common/cmd_ide.c reading Image from IDE device OK
3202 52 common/cmd_nand.c before loading a Image from a NAND device
3203 -53 common/cmd_nand.c Bad usage of "nand" command
3204 53 common/cmd_nand.c correct usage of "nand" command
3205 -54 common/cmd_nand.c No boot device
3206 54 common/cmd_nand.c boot device found
3207 -55 common/cmd_nand.c Unknown Chip ID on boot device
3208 55 common/cmd_nand.c correct chip ID found, device available
3209 -56 common/cmd_nand.c Error reading Image Header on boot device
3210 56 common/cmd_nand.c reading Image Header from NAND device OK
3211 -57 common/cmd_nand.c Image header has bad magic number
3212 57 common/cmd_nand.c Image header has correct magic number
3213 -58 common/cmd_nand.c Error reading Image from NAND device
3214 58 common/cmd_nand.c reading Image from NAND device OK
3216 -60 common/env_common.c Environment has a bad CRC, using default
3218 64 net/eth.c starting with Ethernet configuration.
3219 -64 net/eth.c no Ethernet found.
3220 65 net/eth.c Ethernet found.
3222 -80 common/cmd_net.c usage wrong
3223 80 common/cmd_net.c before calling net_loop()
3224 -81 common/cmd_net.c some error in net_loop() occurred
3225 81 common/cmd_net.c net_loop() back without error
3226 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
3227 82 common/cmd_net.c trying automatic boot
3228 83 common/cmd_net.c running "source" command
3229 -83 common/cmd_net.c some error in automatic boot or "source" command
3230 84 common/cmd_net.c end without errors
3235 100 common/cmd_bootm.c Kernel FIT Image has correct format
3236 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
3237 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
3238 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
3239 102 common/cmd_bootm.c Kernel unit name specified
3240 -103 common/cmd_bootm.c Can't get kernel subimage node offset
3241 103 common/cmd_bootm.c Found configuration node
3242 104 common/cmd_bootm.c Got kernel subimage node offset
3243 -104 common/cmd_bootm.c Kernel subimage hash verification failed
3244 105 common/cmd_bootm.c Kernel subimage hash verification OK
3245 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
3246 106 common/cmd_bootm.c Architecture check OK
3247 -106 common/cmd_bootm.c Kernel subimage has wrong type
3248 107 common/cmd_bootm.c Kernel subimage type OK
3249 -107 common/cmd_bootm.c Can't get kernel subimage data/size
3250 108 common/cmd_bootm.c Got kernel subimage data/size
3251 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
3252 -109 common/cmd_bootm.c Can't get kernel subimage type
3253 -110 common/cmd_bootm.c Can't get kernel subimage comp
3254 -111 common/cmd_bootm.c Can't get kernel subimage os
3255 -112 common/cmd_bootm.c Can't get kernel subimage load address
3256 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
3258 120 common/image.c Start initial ramdisk verification
3259 -120 common/image.c Ramdisk FIT image has incorrect format
3260 121 common/image.c Ramdisk FIT image has correct format
3261 122 common/image.c No ramdisk subimage unit name, using configuration
3262 -122 common/image.c Can't get configuration for ramdisk subimage
3263 123 common/image.c Ramdisk unit name specified
3264 -124 common/image.c Can't get ramdisk subimage node offset
3265 125 common/image.c Got ramdisk subimage node offset
3266 -125 common/image.c Ramdisk subimage hash verification failed
3267 126 common/image.c Ramdisk subimage hash verification OK
3268 -126 common/image.c Ramdisk subimage for unsupported architecture
3269 127 common/image.c Architecture check OK
3270 -127 common/image.c Can't get ramdisk subimage data/size
3271 128 common/image.c Got ramdisk subimage data/size
3272 129 common/image.c Can't get ramdisk load address
3273 -129 common/image.c Got ramdisk load address
3275 -130 common/cmd_doc.c Incorrect FIT image format
3276 131 common/cmd_doc.c FIT image format OK
3278 -140 common/cmd_ide.c Incorrect FIT image format
3279 141 common/cmd_ide.c FIT image format OK
3281 -150 common/cmd_nand.c Incorrect FIT image format
3282 151 common/cmd_nand.c FIT image format OK
3284 - legacy image format:
3285 CONFIG_IMAGE_FORMAT_LEGACY
3286 enables the legacy image format support in U-Boot.
3289 enabled if CONFIG_FIT_SIGNATURE is not defined.
3291 CONFIG_DISABLE_IMAGE_LEGACY
3292 disable the legacy image format
3294 This define is introduced, as the legacy image format is
3295 enabled per default for backward compatibility.
3297 - FIT image support:
3298 CONFIG_FIT_DISABLE_SHA256
3299 Supporting SHA256 hashes has quite an impact on binary size.
3300 For constrained systems sha256 hash support can be disabled
3303 TODO(sjg@chromium.org): Adjust this option to be positive,
3304 and move it to Kconfig
3306 - Standalone program support:
3307 CONFIG_STANDALONE_LOAD_ADDR
3309 This option defines a board specific value for the
3310 address where standalone program gets loaded, thus
3311 overwriting the architecture dependent default
3314 - Frame Buffer Address:
3317 Define CONFIG_FB_ADDR if you want to use specific
3318 address for frame buffer. This is typically the case
3319 when using a graphics controller has separate video
3320 memory. U-Boot will then place the frame buffer at
3321 the given address instead of dynamically reserving it
3322 in system RAM by calling lcd_setmem(), which grabs
3323 the memory for the frame buffer depending on the
3324 configured panel size.
3326 Please see board_init_f function.
3328 - Automatic software updates via TFTP server
3330 CONFIG_UPDATE_TFTP_CNT_MAX
3331 CONFIG_UPDATE_TFTP_MSEC_MAX
3333 These options enable and control the auto-update feature;
3334 for a more detailed description refer to doc/README.update.
3336 - MTD Support (mtdparts command, UBI support)
3339 Adds the MTD device infrastructure from the Linux kernel.
3340 Needed for mtdparts command support.
3342 CONFIG_MTD_PARTITIONS
3344 Adds the MTD partitioning infrastructure from the Linux
3345 kernel. Needed for UBI support.
3350 Adds commands for interacting with MTD partitions formatted
3351 with the UBI flash translation layer
3353 Requires also defining CONFIG_RBTREE
3355 CONFIG_UBI_SILENCE_MSG
3357 Make the verbose messages from UBI stop printing. This leaves
3358 warnings and errors enabled.
3361 CONFIG_MTD_UBI_WL_THRESHOLD
3362 This parameter defines the maximum difference between the highest
3363 erase counter value and the lowest erase counter value of eraseblocks
3364 of UBI devices. When this threshold is exceeded, UBI starts performing
3365 wear leveling by means of moving data from eraseblock with low erase
3366 counter to eraseblocks with high erase counter.
3368 The default value should be OK for SLC NAND flashes, NOR flashes and
3369 other flashes which have eraseblock life-cycle 100000 or more.
3370 However, in case of MLC NAND flashes which typically have eraseblock
3371 life-cycle less than 10000, the threshold should be lessened (e.g.,
3372 to 128 or 256, although it does not have to be power of 2).
3376 CONFIG_MTD_UBI_BEB_LIMIT
3377 This option specifies the maximum bad physical eraseblocks UBI
3378 expects on the MTD device (per 1024 eraseblocks). If the
3379 underlying flash does not admit of bad eraseblocks (e.g. NOR
3380 flash), this value is ignored.
3382 NAND datasheets often specify the minimum and maximum NVM
3383 (Number of Valid Blocks) for the flashes' endurance lifetime.
3384 The maximum expected bad eraseblocks per 1024 eraseblocks
3385 then can be calculated as "1024 * (1 - MinNVB / MaxNVB)",
3386 which gives 20 for most NANDs (MaxNVB is basically the total
3387 count of eraseblocks on the chip).
3389 To put it differently, if this value is 20, UBI will try to
3390 reserve about 1.9% of physical eraseblocks for bad blocks
3391 handling. And that will be 1.9% of eraseblocks on the entire
3392 NAND chip, not just the MTD partition UBI attaches. This means
3393 that if you have, say, a NAND flash chip admits maximum 40 bad
3394 eraseblocks, and it is split on two MTD partitions of the same
3395 size, UBI will reserve 40 eraseblocks when attaching a
3400 CONFIG_MTD_UBI_FASTMAP
3401 Fastmap is a mechanism which allows attaching an UBI device
3402 in nearly constant time. Instead of scanning the whole MTD device it
3403 only has to locate a checkpoint (called fastmap) on the device.
3404 The on-flash fastmap contains all information needed to attach
3405 the device. Using fastmap makes only sense on large devices where
3406 attaching by scanning takes long. UBI will not automatically install
3407 a fastmap on old images, but you can set the UBI parameter
3408 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT to 1 if you want so. Please note
3409 that fastmap-enabled images are still usable with UBI implementations
3410 without fastmap support. On typical flash devices the whole fastmap
3411 fits into one PEB. UBI will reserve PEBs to hold two fastmaps.
3413 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT
3414 Set this parameter to enable fastmap automatically on images
3418 CONFIG_MTD_UBI_FM_DEBUG
3419 Enable UBI fastmap debug
3425 Adds commands for interacting with UBI volumes formatted as
3426 UBIFS. UBIFS is read-only in u-boot.
3428 Requires UBI support as well as CONFIG_LZO
3430 CONFIG_UBIFS_SILENCE_MSG
3432 Make the verbose messages from UBIFS stop printing. This leaves
3433 warnings and errors enabled.
3437 Enable building of SPL globally.
3440 LDSCRIPT for linking the SPL binary.
3442 CONFIG_SPL_MAX_FOOTPRINT
3443 Maximum size in memory allocated to the SPL, BSS included.
3444 When defined, the linker checks that the actual memory
3445 used by SPL from _start to __bss_end does not exceed it.
3446 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3447 must not be both defined at the same time.
3450 Maximum size of the SPL image (text, data, rodata, and
3451 linker lists sections), BSS excluded.
3452 When defined, the linker checks that the actual size does
3455 CONFIG_SPL_TEXT_BASE
3456 TEXT_BASE for linking the SPL binary.
3458 CONFIG_SPL_RELOC_TEXT_BASE
3459 Address to relocate to. If unspecified, this is equal to
3460 CONFIG_SPL_TEXT_BASE (i.e. no relocation is done).
3462 CONFIG_SPL_BSS_START_ADDR
3463 Link address for the BSS within the SPL binary.
3465 CONFIG_SPL_BSS_MAX_SIZE
3466 Maximum size in memory allocated to the SPL BSS.
3467 When defined, the linker checks that the actual memory used
3468 by SPL from __bss_start to __bss_end does not exceed it.
3469 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3470 must not be both defined at the same time.
3473 Adress of the start of the stack SPL will use
3475 CONFIG_SPL_PANIC_ON_RAW_IMAGE
3476 When defined, SPL will panic() if the image it has
3477 loaded does not have a signature.
3478 Defining this is useful when code which loads images
3479 in SPL cannot guarantee that absolutely all read errors
3481 An example is the LPC32XX MLC NAND driver, which will
3482 consider that a completely unreadable NAND block is bad,
3483 and thus should be skipped silently.
3485 CONFIG_SPL_ABORT_ON_RAW_IMAGE
3486 When defined, SPL will proceed to another boot method
3487 if the image it has loaded does not have a signature.
3489 CONFIG_SPL_RELOC_STACK
3490 Adress of the start of the stack SPL will use after
3491 relocation. If unspecified, this is equal to
3494 CONFIG_SYS_SPL_MALLOC_START
3495 Starting address of the malloc pool used in SPL.
3496 When this option is set the full malloc is used in SPL and
3497 it is set up by spl_init() and before that, the simple malloc()
3498 can be used if CONFIG_SYS_MALLOC_F is defined.
3500 CONFIG_SYS_SPL_MALLOC_SIZE
3501 The size of the malloc pool used in SPL.
3503 CONFIG_SPL_FRAMEWORK
3504 Enable the SPL framework under common/. This framework
3505 supports MMC, NAND and YMODEM loading of U-Boot and NAND
3506 NAND loading of the Linux Kernel.
3509 Enable booting directly to an OS from SPL.
3510 See also: doc/README.falcon
3512 CONFIG_SPL_DISPLAY_PRINT
3513 For ARM, enable an optional function to print more information
3514 about the running system.
3516 CONFIG_SPL_INIT_MINIMAL
3517 Arch init code should be built for a very small image
3519 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR,
3520 CONFIG_SYS_U_BOOT_MAX_SIZE_SECTORS,
3521 Address and partition on the MMC to load U-Boot from
3522 when the MMC is being used in raw mode.
3524 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_PARTITION
3525 Partition on the MMC to load U-Boot from when the MMC is being
3528 CONFIG_SYS_MMCSD_RAW_MODE_KERNEL_SECTOR
3529 Sector to load kernel uImage from when MMC is being
3530 used in raw mode (for Falcon mode)
3532 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTOR,
3533 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTORS
3534 Sector and number of sectors to load kernel argument
3535 parameters from when MMC is being used in raw mode
3538 CONFIG_SYS_MMCSD_FS_BOOT_PARTITION
3539 Partition on the MMC to load U-Boot from when the MMC is being
3542 CONFIG_SPL_FS_LOAD_PAYLOAD_NAME
3543 Filename to read to load U-Boot when reading from filesystem
3545 CONFIG_SPL_FS_LOAD_KERNEL_NAME
3546 Filename to read to load kernel uImage when reading
3547 from filesystem (for Falcon mode)
3549 CONFIG_SPL_FS_LOAD_ARGS_NAME
3550 Filename to read to load kernel argument parameters
3551 when reading from filesystem (for Falcon mode)
3553 CONFIG_SPL_MPC83XX_WAIT_FOR_NAND
3554 Set this for NAND SPL on PPC mpc83xx targets, so that
3555 start.S waits for the rest of the SPL to load before
3556 continuing (the hardware starts execution after just
3557 loading the first page rather than the full 4K).
3559 CONFIG_SPL_SKIP_RELOCATE
3560 Avoid SPL relocation
3562 CONFIG_SPL_NAND_BASE
3563 Include nand_base.c in the SPL. Requires
3564 CONFIG_SPL_NAND_DRIVERS.
3566 CONFIG_SPL_NAND_DRIVERS
3567 SPL uses normal NAND drivers, not minimal drivers.
3570 Include standard software ECC in the SPL
3572 CONFIG_SPL_NAND_SIMPLE
3573 Support for NAND boot using simple NAND drivers that
3574 expose the cmd_ctrl() interface.
3577 Support for a lightweight UBI (fastmap) scanner and
3580 CONFIG_SPL_NAND_RAW_ONLY
3581 Support to boot only raw u-boot.bin images. Use this only
3582 if you need to save space.
3584 CONFIG_SPL_COMMON_INIT_DDR
3585 Set for common ddr init with serial presence detect in
3588 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
3589 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
3590 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
3591 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
3592 CONFIG_SYS_NAND_ECCBYTES
3593 Defines the size and behavior of the NAND that SPL uses
3596 CONFIG_SPL_NAND_BOOT
3597 Add support NAND boot
3599 CONFIG_SYS_NAND_U_BOOT_OFFS
3600 Location in NAND to read U-Boot from
3602 CONFIG_SYS_NAND_U_BOOT_DST
3603 Location in memory to load U-Boot to
3605 CONFIG_SYS_NAND_U_BOOT_SIZE
3606 Size of image to load
3608 CONFIG_SYS_NAND_U_BOOT_START
3609 Entry point in loaded image to jump to
3611 CONFIG_SYS_NAND_HW_ECC_OOBFIRST
3612 Define this if you need to first read the OOB and then the
3613 data. This is used, for example, on davinci platforms.
3615 CONFIG_SPL_OMAP3_ID_NAND
3616 Support for an OMAP3-specific set of functions to return the
3617 ID and MFR of the first attached NAND chip, if present.
3619 CONFIG_SPL_RAM_DEVICE
3620 Support for running image already present in ram, in SPL binary
3623 Image offset to which the SPL should be padded before appending
3624 the SPL payload. By default, this is defined as
3625 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3626 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3627 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3630 Final target image containing SPL and payload. Some SPLs
3631 use an arch-specific makefile fragment instead, for
3632 example if more than one image needs to be produced.
3634 CONFIG_FIT_SPL_PRINT
3635 Printing information about a FIT image adds quite a bit of
3636 code to SPL. So this is normally disabled in SPL. Use this
3637 option to re-enable it. This will affect the output of the
3638 bootm command when booting a FIT image.
3642 Enable building of TPL globally.
3645 Image offset to which the TPL should be padded before appending
3646 the TPL payload. By default, this is defined as
3647 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3648 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3649 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3651 - Interrupt support (PPC):
3653 There are common interrupt_init() and timer_interrupt()
3654 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
3655 for CPU specific initialization. interrupt_init_cpu()
3656 should set decrementer_count to appropriate value. If
3657 CPU resets decrementer automatically after interrupt
3658 (ppc4xx) it should set decrementer_count to zero.
3659 timer_interrupt() calls timer_interrupt_cpu() for CPU
3660 specific handling. If board has watchdog / status_led
3661 / other_activity_monitor it works automatically from
3662 general timer_interrupt().
3665 Board initialization settings:
3666 ------------------------------
3668 During Initialization u-boot calls a number of board specific functions
3669 to allow the preparation of board specific prerequisites, e.g. pin setup
3670 before drivers are initialized. To enable these callbacks the
3671 following configuration macros have to be defined. Currently this is
3672 architecture specific, so please check arch/your_architecture/lib/board.c
3673 typically in board_init_f() and board_init_r().
3675 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
3676 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
3677 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
3678 - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
3680 Configuration Settings:
3681 -----------------------
3683 - CONFIG_SYS_SUPPORT_64BIT_DATA: Defined automatically if compiled as 64-bit.
3684 Optionally it can be defined to support 64-bit memory commands.
3686 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
3687 undefine this when you're short of memory.
3689 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
3690 width of the commands listed in the 'help' command output.
3692 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
3693 prompt for user input.
3695 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
3697 - CONFIG_SYS_PBSIZE: Buffer size for Console output
3699 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
3701 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
3702 the application (usually a Linux kernel) when it is
3705 - CONFIG_SYS_BAUDRATE_TABLE:
3706 List of legal baudrate settings for this board.
3708 - CONFIG_SYS_CONSOLE_INFO_QUIET
3709 Suppress display of console information at boot.
3711 - CONFIG_SYS_CONSOLE_IS_IN_ENV
3712 If the board specific function
3713 extern int overwrite_console (void);
3714 returns 1, the stdin, stderr and stdout are switched to the
3715 serial port, else the settings in the environment are used.
3717 - CONFIG_SYS_CONSOLE_OVERWRITE_ROUTINE
3718 Enable the call to overwrite_console().
3720 - CONFIG_SYS_CONSOLE_ENV_OVERWRITE
3721 Enable overwrite of previous console environment settings.
3723 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
3724 Begin and End addresses of the area used by the
3727 - CONFIG_SYS_ALT_MEMTEST:
3728 Enable an alternate, more extensive memory test.
3730 - CONFIG_SYS_MEMTEST_SCRATCH:
3731 Scratch address used by the alternate memory test
3732 You only need to set this if address zero isn't writeable
3734 - CONFIG_SYS_MEM_RESERVE_SECURE
3735 Only implemented for ARMv8 for now.
3736 If defined, the size of CONFIG_SYS_MEM_RESERVE_SECURE memory
3737 is substracted from total RAM and won't be reported to OS.
3738 This memory can be used as secure memory. A variable
3739 gd->arch.secure_ram is used to track the location. In systems
3740 the RAM base is not zero, or RAM is divided into banks,
3741 this variable needs to be recalcuated to get the address.
3743 - CONFIG_SYS_MEM_TOP_HIDE:
3744 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
3745 this specified memory area will get subtracted from the top
3746 (end) of RAM and won't get "touched" at all by U-Boot. By
3747 fixing up gd->ram_size the Linux kernel should gets passed
3748 the now "corrected" memory size and won't touch it either.
3749 This should work for arch/ppc and arch/powerpc. Only Linux
3750 board ports in arch/powerpc with bootwrapper support that
3751 recalculate the memory size from the SDRAM controller setup
3752 will have to get fixed in Linux additionally.
3754 This option can be used as a workaround for the 440EPx/GRx
3755 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
3758 WARNING: Please make sure that this value is a multiple of
3759 the Linux page size (normally 4k). If this is not the case,
3760 then the end address of the Linux memory will be located at a
3761 non page size aligned address and this could cause major
3764 - CONFIG_SYS_LOADS_BAUD_CHANGE:
3765 Enable temporary baudrate change while serial download
3767 - CONFIG_SYS_SDRAM_BASE:
3768 Physical start address of SDRAM. _Must_ be 0 here.
3770 - CONFIG_SYS_MBIO_BASE:
3771 Physical start address of Motherboard I/O (if using a
3774 - CONFIG_SYS_FLASH_BASE:
3775 Physical start address of Flash memory.
3777 - CONFIG_SYS_MONITOR_BASE:
3778 Physical start address of boot monitor code (set by
3779 make config files to be same as the text base address
3780 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
3781 CONFIG_SYS_FLASH_BASE when booting from flash.
3783 - CONFIG_SYS_MONITOR_LEN:
3784 Size of memory reserved for monitor code, used to
3785 determine _at_compile_time_ (!) if the environment is
3786 embedded within the U-Boot image, or in a separate
3789 - CONFIG_SYS_MALLOC_LEN:
3790 Size of DRAM reserved for malloc() use.
3792 - CONFIG_SYS_MALLOC_F_LEN
3793 Size of the malloc() pool for use before relocation. If
3794 this is defined, then a very simple malloc() implementation
3795 will become available before relocation. The address is just
3796 below the global data, and the stack is moved down to make
3799 This feature allocates regions with increasing addresses
3800 within the region. calloc() is supported, but realloc()
3801 is not available. free() is supported but does nothing.
3802 The memory will be freed (or in fact just forgotten) when
3803 U-Boot relocates itself.
3805 - CONFIG_SYS_MALLOC_SIMPLE
3806 Provides a simple and small malloc() and calloc() for those
3807 boards which do not use the full malloc in SPL (which is
3808 enabled with CONFIG_SYS_SPL_MALLOC_START).
3810 - CONFIG_SYS_NONCACHED_MEMORY:
3811 Size of non-cached memory area. This area of memory will be
3812 typically located right below the malloc() area and mapped
3813 uncached in the MMU. This is useful for drivers that would
3814 otherwise require a lot of explicit cache maintenance. For
3815 some drivers it's also impossible to properly maintain the
3816 cache. For example if the regions that need to be flushed
3817 are not a multiple of the cache-line size, *and* padding
3818 cannot be allocated between the regions to align them (i.e.
3819 if the HW requires a contiguous array of regions, and the
3820 size of each region is not cache-aligned), then a flush of
3821 one region may result in overwriting data that hardware has
3822 written to another region in the same cache-line. This can
3823 happen for example in network drivers where descriptors for
3824 buffers are typically smaller than the CPU cache-line (e.g.
3825 16 bytes vs. 32 or 64 bytes).
3827 Non-cached memory is only supported on 32-bit ARM at present.
3829 - CONFIG_SYS_BOOTM_LEN:
3830 Normally compressed uImages are limited to an
3831 uncompressed size of 8 MBytes. If this is not enough,
3832 you can define CONFIG_SYS_BOOTM_LEN in your board config file
3833 to adjust this setting to your needs.
3835 - CONFIG_SYS_BOOTMAPSZ:
3836 Maximum size of memory mapped by the startup code of
3837 the Linux kernel; all data that must be processed by
3838 the Linux kernel (bd_info, boot arguments, FDT blob if
3839 used) must be put below this limit, unless "bootm_low"
3840 environment variable is defined and non-zero. In such case
3841 all data for the Linux kernel must be between "bootm_low"
3842 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
3843 variable "bootm_mapsize" will override the value of
3844 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
3845 then the value in "bootm_size" will be used instead.
3847 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
3848 Enable initrd_high functionality. If defined then the
3849 initrd_high feature is enabled and the bootm ramdisk subcommand
3852 - CONFIG_SYS_BOOT_GET_CMDLINE:
3853 Enables allocating and saving kernel cmdline in space between
3854 "bootm_low" and "bootm_low" + BOOTMAPSZ.
3856 - CONFIG_SYS_BOOT_GET_KBD:
3857 Enables allocating and saving a kernel copy of the bd_info in
3858 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
3860 - CONFIG_SYS_MAX_FLASH_BANKS:
3861 Max number of Flash memory banks
3863 - CONFIG_SYS_MAX_FLASH_SECT:
3864 Max number of sectors on a Flash chip
3866 - CONFIG_SYS_FLASH_ERASE_TOUT:
3867 Timeout for Flash erase operations (in ms)
3869 - CONFIG_SYS_FLASH_WRITE_TOUT:
3870 Timeout for Flash write operations (in ms)
3872 - CONFIG_SYS_FLASH_LOCK_TOUT
3873 Timeout for Flash set sector lock bit operation (in ms)
3875 - CONFIG_SYS_FLASH_UNLOCK_TOUT
3876 Timeout for Flash clear lock bits operation (in ms)
3878 - CONFIG_SYS_FLASH_PROTECTION
3879 If defined, hardware flash sectors protection is used
3880 instead of U-Boot software protection.
3882 - CONFIG_SYS_DIRECT_FLASH_TFTP:
3884 Enable TFTP transfers directly to flash memory;
3885 without this option such a download has to be
3886 performed in two steps: (1) download to RAM, and (2)
3887 copy from RAM to flash.
3889 The two-step approach is usually more reliable, since
3890 you can check if the download worked before you erase
3891 the flash, but in some situations (when system RAM is
3892 too limited to allow for a temporary copy of the
3893 downloaded image) this option may be very useful.
3895 - CONFIG_SYS_FLASH_CFI:
3896 Define if the flash driver uses extra elements in the
3897 common flash structure for storing flash geometry.
3899 - CONFIG_FLASH_CFI_DRIVER
3900 This option also enables the building of the cfi_flash driver
3901 in the drivers directory
3903 - CONFIG_FLASH_CFI_MTD
3904 This option enables the building of the cfi_mtd driver
3905 in the drivers directory. The driver exports CFI flash
3908 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
3909 Use buffered writes to flash.
3911 - CONFIG_FLASH_SPANSION_S29WS_N
3912 s29ws-n MirrorBit flash has non-standard addresses for buffered
3915 - CONFIG_SYS_FLASH_QUIET_TEST
3916 If this option is defined, the common CFI flash doesn't
3917 print it's warning upon not recognized FLASH banks. This
3918 is useful, if some of the configured banks are only
3919 optionally available.
3921 - CONFIG_FLASH_SHOW_PROGRESS
3922 If defined (must be an integer), print out countdown
3923 digits and dots. Recommended value: 45 (9..1) for 80
3924 column displays, 15 (3..1) for 40 column displays.
3926 - CONFIG_FLASH_VERIFY
3927 If defined, the content of the flash (destination) is compared
3928 against the source after the write operation. An error message
3929 will be printed when the contents are not identical.
3930 Please note that this option is useless in nearly all cases,
3931 since such flash programming errors usually are detected earlier
3932 while unprotecting/erasing/programming. Please only enable
3933 this option if you really know what you are doing.
3935 - CONFIG_SYS_RX_ETH_BUFFER:
3936 Defines the number of Ethernet receive buffers. On some
3937 Ethernet controllers it is recommended to set this value
3938 to 8 or even higher (EEPRO100 or 405 EMAC), since all
3939 buffers can be full shortly after enabling the interface
3940 on high Ethernet traffic.
3941 Defaults to 4 if not defined.
3943 - CONFIG_ENV_MAX_ENTRIES
3945 Maximum number of entries in the hash table that is used
3946 internally to store the environment settings. The default
3947 setting is supposed to be generous and should work in most
3948 cases. This setting can be used to tune behaviour; see
3949 lib/hashtable.c for details.
3951 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3952 - CONFIG_ENV_FLAGS_LIST_STATIC
3953 Enable validation of the values given to environment variables when
3954 calling env set. Variables can be restricted to only decimal,
3955 hexadecimal, or boolean. If CONFIG_CMD_NET is also defined,
3956 the variables can also be restricted to IP address or MAC address.
3958 The format of the list is:
3959 type_attribute = [s|d|x|b|i|m]
3960 access_attribute = [a|r|o|c]
3961 attributes = type_attribute[access_attribute]
3962 entry = variable_name[:attributes]
3965 The type attributes are:
3966 s - String (default)
3969 b - Boolean ([1yYtT|0nNfF])
3973 The access attributes are:
3979 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3980 Define this to a list (string) to define the ".flags"
3981 environment variable in the default or embedded environment.
3983 - CONFIG_ENV_FLAGS_LIST_STATIC
3984 Define this to a list (string) to define validation that
3985 should be done if an entry is not found in the ".flags"
3986 environment variable. To override a setting in the static
3987 list, simply add an entry for the same variable name to the
3990 If CONFIG_REGEX is defined, the variable_name above is evaluated as a
3991 regular expression. This allows multiple variables to define the same
3992 flags without explicitly listing them for each variable.
3994 - CONFIG_ENV_ACCESS_IGNORE_FORCE
3995 If defined, don't allow the -f switch to env set override variable
3998 - CONFIG_OMAP_PLATFORM_RESET_TIME_MAX_USEC (OMAP only)
3999 This is set by OMAP boards for the max time that reset should
4000 be asserted. See doc/README.omap-reset-time for details on how
4001 the value can be calculated on a given board.
4004 If stdint.h is available with your toolchain you can define this
4005 option to enable it. You can provide option 'USE_STDINT=1' when
4006 building U-Boot to enable this.
4008 The following definitions that deal with the placement and management
4009 of environment data (variable area); in general, we support the
4010 following configurations:
4012 - CONFIG_BUILD_ENVCRC:
4014 Builds up envcrc with the target environment so that external utils
4015 may easily extract it and embed it in final U-Boot images.
4017 - CONFIG_ENV_IS_IN_FLASH:
4019 Define this if the environment is in flash memory.
4021 a) The environment occupies one whole flash sector, which is
4022 "embedded" in the text segment with the U-Boot code. This
4023 happens usually with "bottom boot sector" or "top boot
4024 sector" type flash chips, which have several smaller
4025 sectors at the start or the end. For instance, such a
4026 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
4027 such a case you would place the environment in one of the
4028 4 kB sectors - with U-Boot code before and after it. With
4029 "top boot sector" type flash chips, you would put the
4030 environment in one of the last sectors, leaving a gap
4031 between U-Boot and the environment.
4033 - CONFIG_ENV_OFFSET:
4035 Offset of environment data (variable area) to the
4036 beginning of flash memory; for instance, with bottom boot
4037 type flash chips the second sector can be used: the offset
4038 for this sector is given here.
4040 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
4044 This is just another way to specify the start address of
4045 the flash sector containing the environment (instead of
4048 - CONFIG_ENV_SECT_SIZE:
4050 Size of the sector containing the environment.
4053 b) Sometimes flash chips have few, equal sized, BIG sectors.
4054 In such a case you don't want to spend a whole sector for
4059 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
4060 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
4061 of this flash sector for the environment. This saves
4062 memory for the RAM copy of the environment.
4064 It may also save flash memory if you decide to use this
4065 when your environment is "embedded" within U-Boot code,
4066 since then the remainder of the flash sector could be used
4067 for U-Boot code. It should be pointed out that this is
4068 STRONGLY DISCOURAGED from a robustness point of view:
4069 updating the environment in flash makes it always
4070 necessary to erase the WHOLE sector. If something goes
4071 wrong before the contents has been restored from a copy in
4072 RAM, your target system will be dead.
4074 - CONFIG_ENV_ADDR_REDUND
4075 CONFIG_ENV_SIZE_REDUND
4077 These settings describe a second storage area used to hold
4078 a redundant copy of the environment data, so that there is
4079 a valid backup copy in case there is a power failure during
4080 a "saveenv" operation.
4082 BE CAREFUL! Any changes to the flash layout, and some changes to the
4083 source code will make it necessary to adapt <board>/u-boot.lds*
4087 - CONFIG_ENV_IS_IN_NVRAM:
4089 Define this if you have some non-volatile memory device
4090 (NVRAM, battery buffered SRAM) which you want to use for the
4096 These two #defines are used to determine the memory area you
4097 want to use for environment. It is assumed that this memory
4098 can just be read and written to, without any special
4101 BE CAREFUL! The first access to the environment happens quite early
4102 in U-Boot initialization (when we try to get the setting of for the
4103 console baudrate). You *MUST* have mapped your NVRAM area then, or
4106 Please note that even with NVRAM we still use a copy of the
4107 environment in RAM: we could work on NVRAM directly, but we want to
4108 keep settings there always unmodified except somebody uses "saveenv"
4109 to save the current settings.
4112 - CONFIG_ENV_IS_IN_EEPROM:
4114 Use this if you have an EEPROM or similar serial access
4115 device and a driver for it.
4117 - CONFIG_ENV_OFFSET:
4120 These two #defines specify the offset and size of the
4121 environment area within the total memory of your EEPROM.
4123 - CONFIG_SYS_I2C_EEPROM_ADDR:
4124 If defined, specified the chip address of the EEPROM device.
4125 The default address is zero.
4127 - CONFIG_SYS_I2C_EEPROM_BUS:
4128 If defined, specified the i2c bus of the EEPROM device.
4130 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
4131 If defined, the number of bits used to address bytes in a
4132 single page in the EEPROM device. A 64 byte page, for example
4133 would require six bits.
4135 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
4136 If defined, the number of milliseconds to delay between
4137 page writes. The default is zero milliseconds.
4139 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
4140 The length in bytes of the EEPROM memory array address. Note
4141 that this is NOT the chip address length!
4143 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
4144 EEPROM chips that implement "address overflow" are ones
4145 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
4146 address and the extra bits end up in the "chip address" bit
4147 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
4150 Note that we consider the length of the address field to
4151 still be one byte because the extra address bits are hidden
4152 in the chip address.
4154 - CONFIG_SYS_EEPROM_SIZE:
4155 The size in bytes of the EEPROM device.
4157 - CONFIG_ENV_EEPROM_IS_ON_I2C
4158 define this, if you have I2C and SPI activated, and your
4159 EEPROM, which holds the environment, is on the I2C bus.
4161 - CONFIG_I2C_ENV_EEPROM_BUS
4162 if you have an Environment on an EEPROM reached over
4163 I2C muxes, you can define here, how to reach this
4164 EEPROM. For example:
4166 #define CONFIG_I2C_ENV_EEPROM_BUS 1
4168 EEPROM which holds the environment, is reached over
4169 a pca9547 i2c mux with address 0x70, channel 3.
4171 - CONFIG_ENV_IS_IN_DATAFLASH:
4173 Define this if you have a DataFlash memory device which you
4174 want to use for the environment.
4176 - CONFIG_ENV_OFFSET:
4180 These three #defines specify the offset and size of the
4181 environment area within the total memory of your DataFlash placed
4182 at the specified address.
4184 - CONFIG_ENV_IS_IN_SPI_FLASH:
4186 Define this if you have a SPI Flash memory device which you
4187 want to use for the environment.
4189 - CONFIG_ENV_OFFSET:
4192 These two #defines specify the offset and size of the
4193 environment area within the SPI Flash. CONFIG_ENV_OFFSET must be
4194 aligned to an erase sector boundary.
4196 - CONFIG_ENV_SECT_SIZE:
4198 Define the SPI flash's sector size.
4200 - CONFIG_ENV_OFFSET_REDUND (optional):
4202 This setting describes a second storage area of CONFIG_ENV_SIZE
4203 size used to hold a redundant copy of the environment data, so
4204 that there is a valid backup copy in case there is a power failure
4205 during a "saveenv" operation. CONFIG_ENV_OFFSET_RENDUND must be
4206 aligned to an erase sector boundary.
4208 - CONFIG_ENV_SPI_BUS (optional):
4209 - CONFIG_ENV_SPI_CS (optional):
4211 Define the SPI bus and chip select. If not defined they will be 0.
4213 - CONFIG_ENV_SPI_MAX_HZ (optional):
4215 Define the SPI max work clock. If not defined then use 1MHz.
4217 - CONFIG_ENV_SPI_MODE (optional):
4219 Define the SPI work mode. If not defined then use SPI_MODE_3.
4221 - CONFIG_ENV_IS_IN_REMOTE:
4223 Define this if you have a remote memory space which you
4224 want to use for the local device's environment.
4229 These two #defines specify the address and size of the
4230 environment area within the remote memory space. The
4231 local device can get the environment from remote memory
4232 space by SRIO or PCIE links.
4234 BE CAREFUL! For some special cases, the local device can not use
4235 "saveenv" command. For example, the local device will get the
4236 environment stored in a remote NOR flash by SRIO or PCIE link,
4237 but it can not erase, write this NOR flash by SRIO or PCIE interface.
4239 - CONFIG_ENV_IS_IN_NAND:
4241 Define this if you have a NAND device which you want to use
4242 for the environment.
4244 - CONFIG_ENV_OFFSET:
4247 These two #defines specify the offset and size of the environment
4248 area within the first NAND device. CONFIG_ENV_OFFSET must be
4249 aligned to an erase block boundary.
4251 - CONFIG_ENV_OFFSET_REDUND (optional):
4253 This setting describes a second storage area of CONFIG_ENV_SIZE
4254 size used to hold a redundant copy of the environment data, so
4255 that there is a valid backup copy in case there is a power failure
4256 during a "saveenv" operation. CONFIG_ENV_OFFSET_RENDUND must be
4257 aligned to an erase block boundary.
4259 - CONFIG_ENV_RANGE (optional):
4261 Specifies the length of the region in which the environment
4262 can be written. This should be a multiple of the NAND device's
4263 block size. Specifying a range with more erase blocks than
4264 are needed to hold CONFIG_ENV_SIZE allows bad blocks within
4265 the range to be avoided.
4267 - CONFIG_ENV_OFFSET_OOB (optional):
4269 Enables support for dynamically retrieving the offset of the
4270 environment from block zero's out-of-band data. The
4271 "nand env.oob" command can be used to record this offset.
4272 Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
4273 using CONFIG_ENV_OFFSET_OOB.
4275 - CONFIG_NAND_ENV_DST
4277 Defines address in RAM to which the nand_spl code should copy the
4278 environment. If redundant environment is used, it will be copied to
4279 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
4281 - CONFIG_ENV_IS_IN_UBI:
4283 Define this if you have an UBI volume that you want to use for the
4284 environment. This has the benefit of wear-leveling the environment
4285 accesses, which is important on NAND.
4287 - CONFIG_ENV_UBI_PART:
4289 Define this to a string that is the mtd partition containing the UBI.
4291 - CONFIG_ENV_UBI_VOLUME:
4293 Define this to the name of the volume that you want to store the
4296 - CONFIG_ENV_UBI_VOLUME_REDUND:
4298 Define this to the name of another volume to store a second copy of
4299 the environment in. This will enable redundant environments in UBI.
4300 It is assumed that both volumes are in the same MTD partition.
4302 - CONFIG_UBI_SILENCE_MSG
4303 - CONFIG_UBIFS_SILENCE_MSG
4305 You will probably want to define these to avoid a really noisy system
4306 when storing the env in UBI.
4308 - CONFIG_ENV_IS_IN_FAT:
4309 Define this if you want to use the FAT file system for the environment.
4311 - FAT_ENV_INTERFACE:
4313 Define this to a string that is the name of the block device.
4315 - FAT_ENV_DEV_AND_PART:
4317 Define this to a string to specify the partition of the device. It can
4320 "D:P", "D:0", "D", "D:" or "D:auto" (D, P are integers. And P >= 1)
4321 - "D:P": device D partition P. Error occurs if device D has no
4324 - "D" or "D:": device D partition 1 if device D has partition
4325 table, or the whole device D if has no partition
4327 - "D:auto": first partition in device D with bootable flag set.
4328 If none, first valid partition in device D. If no
4329 partition table then means device D.
4333 It's a string of the FAT file name. This file use to store the
4337 This should be defined. Otherwise it cannot save the environment file.
4339 - CONFIG_ENV_IS_IN_MMC:
4341 Define this if you have an MMC device which you want to use for the
4344 - CONFIG_SYS_MMC_ENV_DEV:
4346 Specifies which MMC device the environment is stored in.
4348 - CONFIG_SYS_MMC_ENV_PART (optional):
4350 Specifies which MMC partition the environment is stored in. If not
4351 set, defaults to partition 0, the user area. Common values might be
4352 1 (first MMC boot partition), 2 (second MMC boot partition).
4354 - CONFIG_ENV_OFFSET:
4357 These two #defines specify the offset and size of the environment
4358 area within the specified MMC device.
4360 If offset is positive (the usual case), it is treated as relative to
4361 the start of the MMC partition. If offset is negative, it is treated
4362 as relative to the end of the MMC partition. This can be useful if
4363 your board may be fitted with different MMC devices, which have
4364 different sizes for the MMC partitions, and you always want the
4365 environment placed at the very end of the partition, to leave the
4366 maximum possible space before it, to store other data.
4368 These two values are in units of bytes, but must be aligned to an
4369 MMC sector boundary.
4371 - CONFIG_ENV_OFFSET_REDUND (optional):
4373 Specifies a second storage area, of CONFIG_ENV_SIZE size, used to
4374 hold a redundant copy of the environment data. This provides a
4375 valid backup copy in case the other copy is corrupted, e.g. due
4376 to a power failure during a "saveenv" operation.
4378 This value may also be positive or negative; this is handled in the
4379 same way as CONFIG_ENV_OFFSET.
4381 This value is also in units of bytes, but must also be aligned to
4382 an MMC sector boundary.
4384 - CONFIG_ENV_SIZE_REDUND (optional):
4386 This value need not be set, even when CONFIG_ENV_OFFSET_REDUND is
4387 set. If this value is set, it must be set to the same value as
4390 - CONFIG_SYS_SPI_INIT_OFFSET
4392 Defines offset to the initial SPI buffer area in DPRAM. The
4393 area is used at an early stage (ROM part) if the environment
4394 is configured to reside in the SPI EEPROM: We need a 520 byte
4395 scratch DPRAM area. It is used between the two initialization
4396 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
4397 to be a good choice since it makes it far enough from the
4398 start of the data area as well as from the stack pointer.
4400 Please note that the environment is read-only until the monitor
4401 has been relocated to RAM and a RAM copy of the environment has been
4402 created; also, when using EEPROM you will have to use getenv_f()
4403 until then to read environment variables.
4405 The environment is protected by a CRC32 checksum. Before the monitor
4406 is relocated into RAM, as a result of a bad CRC you will be working
4407 with the compiled-in default environment - *silently*!!! [This is
4408 necessary, because the first environment variable we need is the
4409 "baudrate" setting for the console - if we have a bad CRC, we don't
4410 have any device yet where we could complain.]
4412 Note: once the monitor has been relocated, then it will complain if
4413 the default environment is used; a new CRC is computed as soon as you
4414 use the "saveenv" command to store a valid environment.
4416 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
4417 Echo the inverted Ethernet link state to the fault LED.
4419 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
4420 also needs to be defined.
4422 - CONFIG_SYS_FAULT_MII_ADDR:
4423 MII address of the PHY to check for the Ethernet link state.
4425 - CONFIG_NS16550_MIN_FUNCTIONS:
4426 Define this if you desire to only have use of the NS16550_init
4427 and NS16550_putc functions for the serial driver located at
4428 drivers/serial/ns16550.c. This option is useful for saving
4429 space for already greatly restricted images, including but not
4430 limited to NAND_SPL configurations.
4432 - CONFIG_DISPLAY_BOARDINFO
4433 Display information about the board that U-Boot is running on
4434 when U-Boot starts up. The board function checkboard() is called
4437 - CONFIG_DISPLAY_BOARDINFO_LATE
4438 Similar to the previous option, but display this information
4439 later, once stdio is running and output goes to the LCD, if
4442 - CONFIG_BOARD_SIZE_LIMIT:
4443 Maximum size of the U-Boot image. When defined, the
4444 build system checks that the actual size does not
4447 Low Level (hardware related) configuration options:
4448 ---------------------------------------------------
4450 - CONFIG_SYS_CACHELINE_SIZE:
4451 Cache Line Size of the CPU.
4453 - CONFIG_SYS_DEFAULT_IMMR:
4454 Default address of the IMMR after system reset.
4456 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
4457 and RPXsuper) to be able to adjust the position of
4458 the IMMR register after a reset.
4460 - CONFIG_SYS_CCSRBAR_DEFAULT:
4461 Default (power-on reset) physical address of CCSR on Freescale
4464 - CONFIG_SYS_CCSRBAR:
4465 Virtual address of CCSR. On a 32-bit build, this is typically
4466 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
4468 CONFIG_SYS_DEFAULT_IMMR must also be set to this value,
4469 for cross-platform code that uses that macro instead.
4471 - CONFIG_SYS_CCSRBAR_PHYS:
4472 Physical address of CCSR. CCSR can be relocated to a new
4473 physical address, if desired. In this case, this macro should
4474 be set to that address. Otherwise, it should be set to the
4475 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
4476 is typically relocated on 36-bit builds. It is recommended
4477 that this macro be defined via the _HIGH and _LOW macros:
4479 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
4480 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
4482 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
4483 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
4484 either 0 (32-bit build) or 0xF (36-bit build). This macro is
4485 used in assembly code, so it must not contain typecasts or
4486 integer size suffixes (e.g. "ULL").
4488 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
4489 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
4490 used in assembly code, so it must not contain typecasts or
4491 integer size suffixes (e.g. "ULL").
4493 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
4494 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
4495 forced to a value that ensures that CCSR is not relocated.
4497 - Floppy Disk Support:
4498 CONFIG_SYS_FDC_DRIVE_NUMBER
4500 the default drive number (default value 0)
4502 CONFIG_SYS_ISA_IO_STRIDE
4504 defines the spacing between FDC chipset registers
4507 CONFIG_SYS_ISA_IO_OFFSET
4509 defines the offset of register from address. It
4510 depends on which part of the data bus is connected to
4511 the FDC chipset. (default value 0)
4513 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
4514 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
4517 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
4518 fdc_hw_init() is called at the beginning of the FDC
4519 setup. fdc_hw_init() must be provided by the board
4520 source code. It is used to make hardware-dependent
4524 Most IDE controllers were designed to be connected with PCI
4525 interface. Only few of them were designed for AHB interface.
4526 When software is doing ATA command and data transfer to
4527 IDE devices through IDE-AHB controller, some additional
4528 registers accessing to these kind of IDE-AHB controller
4531 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
4532 DO NOT CHANGE unless you know exactly what you're
4533 doing! (11-4) [MPC8xx/82xx systems only]
4535 - CONFIG_SYS_INIT_RAM_ADDR:
4537 Start address of memory area that can be used for
4538 initial data and stack; please note that this must be
4539 writable memory that is working WITHOUT special
4540 initialization, i. e. you CANNOT use normal RAM which
4541 will become available only after programming the
4542 memory controller and running certain initialization
4545 U-Boot uses the following memory types:
4546 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
4547 - MPC824X: data cache
4548 - PPC4xx: data cache
4550 - CONFIG_SYS_GBL_DATA_OFFSET:
4552 Offset of the initial data structure in the memory
4553 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
4554 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
4555 data is located at the end of the available space
4556 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
4557 CONFIG_SYS_INIT_DATA_SIZE), and the initial stack is just
4558 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
4559 CONFIG_SYS_GBL_DATA_OFFSET) downward.
4562 On the MPC824X (or other systems that use the data
4563 cache for initial memory) the address chosen for
4564 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
4565 point to an otherwise UNUSED address space between
4566 the top of RAM and the start of the PCI space.
4568 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
4570 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
4572 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
4574 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
4576 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
4578 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
4580 - CONFIG_SYS_OR_TIMING_SDRAM:
4583 - CONFIG_SYS_MAMR_PTA:
4584 periodic timer for refresh
4586 - CONFIG_SYS_DER: Debug Event Register (37-47)
4588 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
4589 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
4590 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
4591 CONFIG_SYS_BR1_PRELIM:
4592 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
4594 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
4595 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
4596 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
4597 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
4599 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
4600 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
4601 Machine Mode Register and Memory Periodic Timer
4602 Prescaler definitions (SDRAM timing)
4604 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
4605 enable I2C microcode relocation patch (MPC8xx);
4606 define relocation offset in DPRAM [DSP2]
4608 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
4609 enable SMC microcode relocation patch (MPC8xx);
4610 define relocation offset in DPRAM [SMC1]
4612 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
4613 enable SPI microcode relocation patch (MPC8xx);
4614 define relocation offset in DPRAM [SCC4]
4616 - CONFIG_SYS_USE_OSCCLK:
4617 Use OSCM clock mode on MBX8xx board. Be careful,
4618 wrong setting might damage your board. Read
4619 doc/README.MBX before setting this variable!
4621 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
4622 Offset of the bootmode word in DPRAM used by post
4623 (Power On Self Tests). This definition overrides
4624 #define'd default value in commproc.h resp.
4627 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
4628 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
4629 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
4630 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
4631 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
4632 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
4633 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
4634 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
4635 Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
4637 - CONFIG_PCI_DISABLE_PCIE:
4638 Disable PCI-Express on systems where it is supported but not
4641 - CONFIG_PCI_ENUM_ONLY
4642 Only scan through and get the devices on the buses.
4643 Don't do any setup work, presumably because someone or
4644 something has already done it, and we don't need to do it
4645 a second time. Useful for platforms that are pre-booted
4646 by coreboot or similar.
4648 - CONFIG_PCI_INDIRECT_BRIDGE:
4649 Enable support for indirect PCI bridges.
4652 Chip has SRIO or not
4655 Board has SRIO 1 port available
4658 Board has SRIO 2 port available
4660 - CONFIG_SRIO_PCIE_BOOT_MASTER
4661 Board can support master function for Boot from SRIO and PCIE
4663 - CONFIG_SYS_SRIOn_MEM_VIRT:
4664 Virtual Address of SRIO port 'n' memory region
4666 - CONFIG_SYS_SRIOn_MEM_PHYS:
4667 Physical Address of SRIO port 'n' memory region
4669 - CONFIG_SYS_SRIOn_MEM_SIZE:
4670 Size of SRIO port 'n' memory region
4672 - CONFIG_SYS_NAND_BUSWIDTH_16BIT
4673 Defined to tell the NAND controller that the NAND chip is using
4675 Not all NAND drivers use this symbol.
4676 Example of drivers that use it:
4677 - drivers/mtd/nand/ndfc.c
4678 - drivers/mtd/nand/mxc_nand.c
4680 - CONFIG_SYS_NDFC_EBC0_CFG
4681 Sets the EBC0_CFG register for the NDFC. If not defined
4682 a default value will be used.
4685 Get DDR timing information from an I2C EEPROM. Common
4686 with pluggable memory modules such as SODIMMs
4689 I2C address of the SPD EEPROM
4691 - CONFIG_SYS_SPD_BUS_NUM
4692 If SPD EEPROM is on an I2C bus other than the first
4693 one, specify here. Note that the value must resolve
4694 to something your driver can deal with.
4696 - CONFIG_SYS_DDR_RAW_TIMING
4697 Get DDR timing information from other than SPD. Common with
4698 soldered DDR chips onboard without SPD. DDR raw timing
4699 parameters are extracted from datasheet and hard-coded into
4700 header files or board specific files.
4702 - CONFIG_FSL_DDR_INTERACTIVE
4703 Enable interactive DDR debugging. See doc/README.fsl-ddr.
4705 - CONFIG_FSL_DDR_SYNC_REFRESH
4706 Enable sync of refresh for multiple controllers.
4708 - CONFIG_FSL_DDR_BIST
4709 Enable built-in memory test for Freescale DDR controllers.
4711 - CONFIG_SYS_83XX_DDR_USES_CS0
4712 Only for 83xx systems. If specified, then DDR should
4713 be configured using CS0 and CS1 instead of CS2 and CS3.
4715 - CONFIG_ETHER_ON_FEC[12]
4716 Define to enable FEC[12] on a 8xx series processor.
4718 - CONFIG_FEC[12]_PHY
4719 Define to the hardcoded PHY address which corresponds
4720 to the given FEC; i. e.
4721 #define CONFIG_FEC1_PHY 4
4722 means that the PHY with address 4 is connected to FEC1
4724 When set to -1, means to probe for first available.
4726 - CONFIG_FEC[12]_PHY_NORXERR
4727 The PHY does not have a RXERR line (RMII only).
4728 (so program the FEC to ignore it).
4731 Enable RMII mode for all FECs.
4732 Note that this is a global option, we can't
4733 have one FEC in standard MII mode and another in RMII mode.
4735 - CONFIG_CRC32_VERIFY
4736 Add a verify option to the crc32 command.
4739 => crc32 -v <address> <count> <crc32>
4741 Where address/count indicate a memory area
4742 and crc32 is the correct crc32 which the
4746 Add the "loopw" memory command. This only takes effect if
4747 the memory commands are activated globally (CONFIG_CMD_MEM).
4750 Add the "mdc" and "mwc" memory commands. These are cyclic
4755 This command will print 4 bytes (10,11,12,13) each 500 ms.
4757 => mwc.l 100 12345678 10
4758 This command will write 12345678 to address 100 all 10 ms.
4760 This only takes effect if the memory commands are activated
4761 globally (CONFIG_CMD_MEM).
4763 - CONFIG_SKIP_LOWLEVEL_INIT
4764 [ARM, NDS32, MIPS only] If this variable is defined, then certain
4765 low level initializations (like setting up the memory
4766 controller) are omitted and/or U-Boot does not
4767 relocate itself into RAM.
4769 Normally this variable MUST NOT be defined. The only
4770 exception is when U-Boot is loaded (to RAM) by some
4771 other boot loader or by a debugger which performs
4772 these initializations itself.
4774 - CONFIG_SKIP_LOWLEVEL_INIT_ONLY
4775 [ARM926EJ-S only] This allows just the call to lowlevel_init()
4776 to be skipped. The normal CP15 init (such as enabling the
4777 instruction cache) is still performed.
4780 Modifies the behaviour of start.S when compiling a loader
4781 that is executed before the actual U-Boot. E.g. when
4782 compiling a NAND SPL.
4785 Modifies the behaviour of start.S when compiling a loader
4786 that is executed after the SPL and before the actual U-Boot.
4787 It is loaded by the SPL.
4789 - CONFIG_SYS_MPC85XX_NO_RESETVEC
4790 Only for 85xx systems. If this variable is specified, the section
4791 .resetvec is not kept and the section .bootpg is placed in the
4792 previous 4k of the .text section.
4794 - CONFIG_ARCH_MAP_SYSMEM
4795 Generally U-Boot (and in particular the md command) uses
4796 effective address. It is therefore not necessary to regard
4797 U-Boot address as virtual addresses that need to be translated
4798 to physical addresses. However, sandbox requires this, since
4799 it maintains its own little RAM buffer which contains all
4800 addressable memory. This option causes some memory accesses
4801 to be mapped through map_sysmem() / unmap_sysmem().
4803 - CONFIG_USE_ARCH_MEMCPY
4804 CONFIG_USE_ARCH_MEMSET
4805 If these options are used a optimized version of memcpy/memset will
4806 be used if available. These functions may be faster under some
4807 conditions but may increase the binary size.
4809 - CONFIG_X86_RESET_VECTOR
4810 If defined, the x86 reset vector code is included. This is not
4811 needed when U-Boot is running from Coreboot.
4814 Defines the MPU clock speed (in MHz).
4816 NOTE : currently only supported on AM335x platforms.
4818 - CONFIG_SPL_AM33XX_ENABLE_RTC32K_OSC:
4819 Enables the RTC32K OSC on AM33xx based plattforms
4821 - CONFIG_SYS_NAND_NO_SUBPAGE_WRITE
4822 Option to disable subpage write in NAND driver
4823 driver that uses this:
4824 drivers/mtd/nand/davinci_nand.c
4826 Freescale QE/FMAN Firmware Support:
4827 -----------------------------------
4829 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
4830 loading of "firmware", which is encoded in the QE firmware binary format.
4831 This firmware often needs to be loaded during U-Boot booting, so macros
4832 are used to identify the storage device (NOR flash, SPI, etc) and the address
4835 - CONFIG_SYS_FMAN_FW_ADDR
4836 The address in the storage device where the FMAN microcode is located. The
4837 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4840 - CONFIG_SYS_QE_FW_ADDR
4841 The address in the storage device where the QE microcode is located. The
4842 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4845 - CONFIG_SYS_QE_FMAN_FW_LENGTH
4846 The maximum possible size of the firmware. The firmware binary format
4847 has a field that specifies the actual size of the firmware, but it
4848 might not be possible to read any part of the firmware unless some
4849 local storage is allocated to hold the entire firmware first.
4851 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
4852 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
4853 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
4854 virtual address in NOR flash.
4856 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
4857 Specifies that QE/FMAN firmware is located in NAND flash.
4858 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
4860 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
4861 Specifies that QE/FMAN firmware is located on the primary SD/MMC
4862 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
4864 - CONFIG_SYS_QE_FMAN_FW_IN_SPIFLASH
4865 Specifies that QE/FMAN firmware is located on the primary SPI
4866 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
4868 - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
4869 Specifies that QE/FMAN firmware is located in the remote (master)
4870 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
4871 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
4872 window->master inbound window->master LAW->the ucode address in
4873 master's memory space.
4875 Freescale Layerscape Management Complex Firmware Support:
4876 ---------------------------------------------------------
4877 The Freescale Layerscape Management Complex (MC) supports the loading of
4879 This firmware often needs to be loaded during U-Boot booting, so macros
4880 are used to identify the storage device (NOR flash, SPI, etc) and the address
4883 - CONFIG_FSL_MC_ENET
4884 Enable the MC driver for Layerscape SoCs.
4886 - CONFIG_SYS_LS_MC_FW_ADDR
4887 The address in the storage device where the firmware is located. The
4888 meaning of this address depends on which CONFIG_SYS_LS_MC_FW_IN_xxx macro
4891 - CONFIG_SYS_LS_MC_FW_LENGTH
4892 The maximum possible size of the firmware. The firmware binary format
4893 has a field that specifies the actual size of the firmware, but it
4894 might not be possible to read any part of the firmware unless some
4895 local storage is allocated to hold the entire firmware first.
4897 - CONFIG_SYS_LS_MC_FW_IN_NOR
4898 Specifies that MC firmware is located in NOR flash, mapped as
4899 normal addressable memory via the LBC. CONFIG_SYS_LS_MC_FW_ADDR is the
4900 virtual address in NOR flash.
4902 Freescale Layerscape Debug Server Support:
4903 -------------------------------------------
4904 The Freescale Layerscape Debug Server Support supports the loading of
4905 "Debug Server firmware" and triggering SP boot-rom.
4906 This firmware often needs to be loaded during U-Boot booting.
4908 - CONFIG_SYS_MC_RSV_MEM_ALIGN
4909 Define alignment of reserved memory MC requires
4914 In order to achieve reproducible builds, timestamps used in the U-Boot build
4915 process have to be set to a fixed value.
4917 This is done using the SOURCE_DATE_EPOCH environment variable.
4918 SOURCE_DATE_EPOCH is to be set on the build host's shell, not as a configuration
4919 option for U-Boot or an environment variable in U-Boot.
4921 SOURCE_DATE_EPOCH should be set to a number of seconds since the epoch, in UTC.
4923 Building the Software:
4924 ======================
4926 Building U-Boot has been tested in several native build environments
4927 and in many different cross environments. Of course we cannot support
4928 all possibly existing versions of cross development tools in all
4929 (potentially obsolete) versions. In case of tool chain problems we
4930 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
4931 which is extensively used to build and test U-Boot.
4933 If you are not using a native environment, it is assumed that you
4934 have GNU cross compiling tools available in your path. In this case,
4935 you must set the environment variable CROSS_COMPILE in your shell.
4936 Note that no changes to the Makefile or any other source files are
4937 necessary. For example using the ELDK on a 4xx CPU, please enter:
4939 $ CROSS_COMPILE=ppc_4xx-
4940 $ export CROSS_COMPILE
4942 Note: If you wish to generate Windows versions of the utilities in
4943 the tools directory you can use the MinGW toolchain
4944 (http://www.mingw.org). Set your HOST tools to the MinGW
4945 toolchain and execute 'make tools'. For example:
4947 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
4949 Binaries such as tools/mkimage.exe will be created which can
4950 be executed on computers running Windows.
4952 U-Boot is intended to be simple to build. After installing the
4953 sources you must configure U-Boot for one specific board type. This
4958 where "NAME_defconfig" is the name of one of the existing configu-
4959 rations; see boards.cfg for supported names.
4961 Note: for some board special configuration names may exist; check if
4962 additional information is available from the board vendor; for
4963 instance, the TQM823L systems are available without (standard)
4964 or with LCD support. You can select such additional "features"
4965 when choosing the configuration, i. e.
4967 make TQM823L_defconfig
4968 - will configure for a plain TQM823L, i. e. no LCD support
4970 make TQM823L_LCD_defconfig
4971 - will configure for a TQM823L with U-Boot console on LCD
4976 Finally, type "make all", and you should get some working U-Boot
4977 images ready for download to / installation on your system:
4979 - "u-boot.bin" is a raw binary image
4980 - "u-boot" is an image in ELF binary format
4981 - "u-boot.srec" is in Motorola S-Record format
4983 By default the build is performed locally and the objects are saved
4984 in the source directory. One of the two methods can be used to change
4985 this behavior and build U-Boot to some external directory:
4987 1. Add O= to the make command line invocations:
4989 make O=/tmp/build distclean
4990 make O=/tmp/build NAME_defconfig
4991 make O=/tmp/build all
4993 2. Set environment variable KBUILD_OUTPUT to point to the desired location:
4995 export KBUILD_OUTPUT=/tmp/build
5000 Note that the command line "O=" setting overrides the KBUILD_OUTPUT environment
5004 Please be aware that the Makefiles assume you are using GNU make, so
5005 for instance on NetBSD you might need to use "gmake" instead of
5009 If the system board that you have is not listed, then you will need
5010 to port U-Boot to your hardware platform. To do this, follow these
5013 1. Create a new directory to hold your board specific code. Add any
5014 files you need. In your board directory, you will need at least
5015 the "Makefile" and a "<board>.c".
5016 2. Create a new configuration file "include/configs/<board>.h" for
5018 3. If you're porting U-Boot to a new CPU, then also create a new
5019 directory to hold your CPU specific code. Add any files you need.
5020 4. Run "make <board>_defconfig" with your new name.
5021 5. Type "make", and you should get a working "u-boot.srec" file
5022 to be installed on your target system.
5023 6. Debug and solve any problems that might arise.
5024 [Of course, this last step is much harder than it sounds.]
5027 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
5028 ==============================================================
5030 If you have modified U-Boot sources (for instance added a new board
5031 or support for new devices, a new CPU, etc.) you are expected to
5032 provide feedback to the other developers. The feedback normally takes
5033 the form of a "patch", i. e. a context diff against a certain (latest
5034 official or latest in the git repository) version of U-Boot sources.
5036 But before you submit such a patch, please verify that your modifi-
5037 cation did not break existing code. At least make sure that *ALL* of
5038 the supported boards compile WITHOUT ANY compiler warnings. To do so,
5039 just run the buildman script (tools/buildman/buildman), which will
5040 configure and build U-Boot for ALL supported system. Be warned, this
5041 will take a while. Please see the buildman README, or run 'buildman -H'
5045 See also "U-Boot Porting Guide" below.
5048 Monitor Commands - Overview:
5049 ============================
5051 go - start application at address 'addr'
5052 run - run commands in an environment variable
5053 bootm - boot application image from memory
5054 bootp - boot image via network using BootP/TFTP protocol
5055 bootz - boot zImage from memory
5056 tftpboot- boot image via network using TFTP protocol
5057 and env variables "ipaddr" and "serverip"
5058 (and eventually "gatewayip")
5059 tftpput - upload a file via network using TFTP protocol
5060 rarpboot- boot image via network using RARP/TFTP protocol
5061 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
5062 loads - load S-Record file over serial line
5063 loadb - load binary file over serial line (kermit mode)
5065 mm - memory modify (auto-incrementing)
5066 nm - memory modify (constant address)
5067 mw - memory write (fill)
5069 cmp - memory compare
5070 crc32 - checksum calculation
5071 i2c - I2C sub-system
5072 sspi - SPI utility commands
5073 base - print or set address offset
5074 printenv- print environment variables
5075 setenv - set environment variables
5076 saveenv - save environment variables to persistent storage
5077 protect - enable or disable FLASH write protection
5078 erase - erase FLASH memory
5079 flinfo - print FLASH memory information
5080 nand - NAND memory operations (see doc/README.nand)
5081 bdinfo - print Board Info structure
5082 iminfo - print header information for application image
5083 coninfo - print console devices and informations
5084 ide - IDE sub-system
5085 loop - infinite loop on address range
5086 loopw - infinite write loop on address range
5087 mtest - simple RAM test
5088 icache - enable or disable instruction cache
5089 dcache - enable or disable data cache
5090 reset - Perform RESET of the CPU
5091 echo - echo args to console
5092 version - print monitor version
5093 help - print online help
5094 ? - alias for 'help'
5097 Monitor Commands - Detailed Description:
5098 ========================================
5102 For now: just type "help <command>".
5105 Environment Variables:
5106 ======================
5108 U-Boot supports user configuration using Environment Variables which
5109 can be made persistent by saving to Flash memory.
5111 Environment Variables are set using "setenv", printed using
5112 "printenv", and saved to Flash using "saveenv". Using "setenv"
5113 without a value can be used to delete a variable from the
5114 environment. As long as you don't save the environment you are
5115 working with an in-memory copy. In case the Flash area containing the
5116 environment is erased by accident, a default environment is provided.
5118 Some configuration options can be set using Environment Variables.
5120 List of environment variables (most likely not complete):
5122 baudrate - see CONFIG_BAUDRATE
5124 bootdelay - see CONFIG_BOOTDELAY
5126 bootcmd - see CONFIG_BOOTCOMMAND
5128 bootargs - Boot arguments when booting an RTOS image
5130 bootfile - Name of the image to load with TFTP
5132 bootm_low - Memory range available for image processing in the bootm
5133 command can be restricted. This variable is given as
5134 a hexadecimal number and defines lowest address allowed
5135 for use by the bootm command. See also "bootm_size"
5136 environment variable. Address defined by "bootm_low" is
5137 also the base of the initial memory mapping for the Linux
5138 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
5141 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
5142 This variable is given as a hexadecimal number and it
5143 defines the size of the memory region starting at base
5144 address bootm_low that is accessible by the Linux kernel
5145 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
5146 as the default value if it is defined, and bootm_size is
5149 bootm_size - Memory range available for image processing in the bootm
5150 command can be restricted. This variable is given as
5151 a hexadecimal number and defines the size of the region
5152 allowed for use by the bootm command. See also "bootm_low"
5153 environment variable.
5155 updatefile - Location of the software update file on a TFTP server, used
5156 by the automatic software update feature. Please refer to
5157 documentation in doc/README.update for more details.
5159 autoload - if set to "no" (any string beginning with 'n'),
5160 "bootp" will just load perform a lookup of the
5161 configuration from the BOOTP server, but not try to
5162 load any image using TFTP
5164 autostart - if set to "yes", an image loaded using the "bootp",
5165 "rarpboot", "tftpboot" or "diskboot" commands will
5166 be automatically started (by internally calling
5169 If set to "no", a standalone image passed to the
5170 "bootm" command will be copied to the load address
5171 (and eventually uncompressed), but NOT be started.
5172 This can be used to load and uncompress arbitrary
5175 fdt_high - if set this restricts the maximum address that the
5176 flattened device tree will be copied into upon boot.
5177 For example, if you have a system with 1 GB memory
5178 at physical address 0x10000000, while Linux kernel
5179 only recognizes the first 704 MB as low memory, you
5180 may need to set fdt_high as 0x3C000000 to have the
5181 device tree blob be copied to the maximum address
5182 of the 704 MB low memory, so that Linux kernel can
5183 access it during the boot procedure.
5185 If this is set to the special value 0xFFFFFFFF then
5186 the fdt will not be copied at all on boot. For this
5187 to work it must reside in writable memory, have
5188 sufficient padding on the end of it for u-boot to
5189 add the information it needs into it, and the memory
5190 must be accessible by the kernel.
5192 fdtcontroladdr- if set this is the address of the control flattened
5193 device tree used by U-Boot when CONFIG_OF_CONTROL is
5196 i2cfast - (PPC405GP|PPC405EP only)
5197 if set to 'y' configures Linux I2C driver for fast
5198 mode (400kHZ). This environment variable is used in
5199 initialization code. So, for changes to be effective
5200 it must be saved and board must be reset.
5202 initrd_high - restrict positioning of initrd images:
5203 If this variable is not set, initrd images will be
5204 copied to the highest possible address in RAM; this
5205 is usually what you want since it allows for
5206 maximum initrd size. If for some reason you want to
5207 make sure that the initrd image is loaded below the
5208 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
5209 variable to a value of "no" or "off" or "0".
5210 Alternatively, you can set it to a maximum upper
5211 address to use (U-Boot will still check that it
5212 does not overwrite the U-Boot stack and data).
5214 For instance, when you have a system with 16 MB
5215 RAM, and want to reserve 4 MB from use by Linux,
5216 you can do this by adding "mem=12M" to the value of
5217 the "bootargs" variable. However, now you must make
5218 sure that the initrd image is placed in the first
5219 12 MB as well - this can be done with
5221 setenv initrd_high 00c00000
5223 If you set initrd_high to 0xFFFFFFFF, this is an
5224 indication to U-Boot that all addresses are legal
5225 for the Linux kernel, including addresses in flash
5226 memory. In this case U-Boot will NOT COPY the
5227 ramdisk at all. This may be useful to reduce the
5228 boot time on your system, but requires that this
5229 feature is supported by your Linux kernel.
5231 ipaddr - IP address; needed for tftpboot command
5233 loadaddr - Default load address for commands like "bootp",
5234 "rarpboot", "tftpboot", "loadb" or "diskboot"
5236 loads_echo - see CONFIG_LOADS_ECHO
5238 serverip - TFTP server IP address; needed for tftpboot command
5240 bootretry - see CONFIG_BOOT_RETRY_TIME
5242 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
5244 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
5246 ethprime - controls which interface is used first.
5248 ethact - controls which interface is currently active.
5249 For example you can do the following
5251 => setenv ethact FEC
5252 => ping 192.168.0.1 # traffic sent on FEC
5253 => setenv ethact SCC
5254 => ping 10.0.0.1 # traffic sent on SCC
5256 ethrotate - When set to "no" U-Boot does not go through all
5257 available network interfaces.
5258 It just stays at the currently selected interface.
5260 netretry - When set to "no" each network operation will
5261 either succeed or fail without retrying.
5262 When set to "once" the network operation will
5263 fail when all the available network interfaces
5264 are tried once without success.
5265 Useful on scripts which control the retry operation
5268 npe_ucode - set load address for the NPE microcode
5270 silent_linux - If set then Linux will be told to boot silently, by
5271 changing the console to be empty. If "yes" it will be
5272 made silent. If "no" it will not be made silent. If
5273 unset, then it will be made silent if the U-Boot console
5276 tftpsrcp - If this is set, the value is used for TFTP's
5279 tftpdstp - If this is set, the value is used for TFTP's UDP
5280 destination port instead of the Well Know Port 69.
5282 tftpblocksize - Block size to use for TFTP transfers; if not set,
5283 we use the TFTP server's default block size
5285 tftptimeout - Retransmission timeout for TFTP packets (in milli-
5286 seconds, minimum value is 1000 = 1 second). Defines
5287 when a packet is considered to be lost so it has to
5288 be retransmitted. The default is 5000 = 5 seconds.
5289 Lowering this value may make downloads succeed
5290 faster in networks with high packet loss rates or
5291 with unreliable TFTP servers.
5293 tftptimeoutcountmax - maximum count of TFTP timeouts (no
5294 unit, minimum value = 0). Defines how many timeouts
5295 can happen during a single file transfer before that
5296 transfer is aborted. The default is 10, and 0 means
5297 'no timeouts allowed'. Increasing this value may help
5298 downloads succeed with high packet loss rates, or with
5299 unreliable TFTP servers or client hardware.
5301 vlan - When set to a value < 4095 the traffic over
5302 Ethernet is encapsulated/received over 802.1q
5305 bootpretryperiod - Period during which BOOTP/DHCP sends retries.
5306 Unsigned value, in milliseconds. If not set, the period will
5307 be either the default (28000), or a value based on
5308 CONFIG_NET_RETRY_COUNT, if defined. This value has
5309 precedence over the valu based on CONFIG_NET_RETRY_COUNT.
5311 The following image location variables contain the location of images
5312 used in booting. The "Image" column gives the role of the image and is
5313 not an environment variable name. The other columns are environment
5314 variable names. "File Name" gives the name of the file on a TFTP
5315 server, "RAM Address" gives the location in RAM the image will be
5316 loaded to, and "Flash Location" gives the image's address in NOR
5317 flash or offset in NAND flash.
5319 *Note* - these variables don't have to be defined for all boards, some
5320 boards currently use other variables for these purposes, and some
5321 boards use these variables for other purposes.
5323 Image File Name RAM Address Flash Location
5324 ----- --------- ----------- --------------
5325 u-boot u-boot u-boot_addr_r u-boot_addr
5326 Linux kernel bootfile kernel_addr_r kernel_addr
5327 device tree blob fdtfile fdt_addr_r fdt_addr
5328 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
5330 The following environment variables may be used and automatically
5331 updated by the network boot commands ("bootp" and "rarpboot"),
5332 depending the information provided by your boot server:
5334 bootfile - see above
5335 dnsip - IP address of your Domain Name Server
5336 dnsip2 - IP address of your secondary Domain Name Server
5337 gatewayip - IP address of the Gateway (Router) to use
5338 hostname - Target hostname
5340 netmask - Subnet Mask
5341 rootpath - Pathname of the root filesystem on the NFS server
5342 serverip - see above
5345 There are two special Environment Variables:
5347 serial# - contains hardware identification information such
5348 as type string and/or serial number
5349 ethaddr - Ethernet address
5351 These variables can be set only once (usually during manufacturing of
5352 the board). U-Boot refuses to delete or overwrite these variables
5353 once they have been set once.
5356 Further special Environment Variables:
5358 ver - Contains the U-Boot version string as printed
5359 with the "version" command. This variable is
5360 readonly (see CONFIG_VERSION_VARIABLE).
5363 Please note that changes to some configuration parameters may take
5364 only effect after the next boot (yes, that's just like Windoze :-).
5367 Callback functions for environment variables:
5368 ---------------------------------------------
5370 For some environment variables, the behavior of u-boot needs to change
5371 when their values are changed. This functionality allows functions to
5372 be associated with arbitrary variables. On creation, overwrite, or
5373 deletion, the callback will provide the opportunity for some side
5374 effect to happen or for the change to be rejected.
5376 The callbacks are named and associated with a function using the
5377 U_BOOT_ENV_CALLBACK macro in your board or driver code.
5379 These callbacks are associated with variables in one of two ways. The
5380 static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC
5381 in the board configuration to a string that defines a list of
5382 associations. The list must be in the following format:
5384 entry = variable_name[:callback_name]
5387 If the callback name is not specified, then the callback is deleted.
5388 Spaces are also allowed anywhere in the list.
5390 Callbacks can also be associated by defining the ".callbacks" variable
5391 with the same list format above. Any association in ".callbacks" will
5392 override any association in the static list. You can define
5393 CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the
5394 ".callbacks" environment variable in the default or embedded environment.
5396 If CONFIG_REGEX is defined, the variable_name above is evaluated as a
5397 regular expression. This allows multiple variables to be connected to
5398 the same callback without explicitly listing them all out.
5401 Command Line Parsing:
5402 =====================
5404 There are two different command line parsers available with U-Boot:
5405 the old "simple" one, and the much more powerful "hush" shell:
5407 Old, simple command line parser:
5408 --------------------------------
5410 - supports environment variables (through setenv / saveenv commands)
5411 - several commands on one line, separated by ';'
5412 - variable substitution using "... ${name} ..." syntax
5413 - special characters ('$', ';') can be escaped by prefixing with '\',
5415 setenv bootcmd bootm \${address}
5416 - You can also escape text by enclosing in single apostrophes, for example:
5417 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
5422 - similar to Bourne shell, with control structures like
5423 if...then...else...fi, for...do...done; while...do...done,
5424 until...do...done, ...
5425 - supports environment ("global") variables (through setenv / saveenv
5426 commands) and local shell variables (through standard shell syntax
5427 "name=value"); only environment variables can be used with "run"
5433 (1) If a command line (or an environment variable executed by a "run"
5434 command) contains several commands separated by semicolon, and
5435 one of these commands fails, then the remaining commands will be
5438 (2) If you execute several variables with one call to run (i. e.
5439 calling run with a list of variables as arguments), any failing
5440 command will cause "run" to terminate, i. e. the remaining
5441 variables are not executed.
5443 Note for Redundant Ethernet Interfaces:
5444 =======================================
5446 Some boards come with redundant Ethernet interfaces; U-Boot supports
5447 such configurations and is capable of automatic selection of a
5448 "working" interface when needed. MAC assignment works as follows:
5450 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
5451 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
5452 "eth1addr" (=>eth1), "eth2addr", ...
5454 If the network interface stores some valid MAC address (for instance
5455 in SROM), this is used as default address if there is NO correspon-
5456 ding setting in the environment; if the corresponding environment
5457 variable is set, this overrides the settings in the card; that means:
5459 o If the SROM has a valid MAC address, and there is no address in the
5460 environment, the SROM's address is used.
5462 o If there is no valid address in the SROM, and a definition in the
5463 environment exists, then the value from the environment variable is
5466 o If both the SROM and the environment contain a MAC address, and
5467 both addresses are the same, this MAC address is used.
5469 o If both the SROM and the environment contain a MAC address, and the
5470 addresses differ, the value from the environment is used and a
5473 o If neither SROM nor the environment contain a MAC address, an error
5474 is raised. If CONFIG_NET_RANDOM_ETHADDR is defined, then in this case
5475 a random, locally-assigned MAC is used.
5477 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
5478 will be programmed into hardware as part of the initialization process. This
5479 may be skipped by setting the appropriate 'ethmacskip' environment variable.
5480 The naming convention is as follows:
5481 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
5486 U-Boot is capable of booting (and performing other auxiliary operations on)
5487 images in two formats:
5489 New uImage format (FIT)
5490 -----------------------
5492 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
5493 to Flattened Device Tree). It allows the use of images with multiple
5494 components (several kernels, ramdisks, etc.), with contents protected by
5495 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
5501 Old image format is based on binary files which can be basically anything,
5502 preceded by a special header; see the definitions in include/image.h for
5503 details; basically, the header defines the following image properties:
5505 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
5506 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
5507 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
5508 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
5510 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
5511 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
5512 Currently supported: ARM, AVR32, Intel x86, MIPS, NDS32, Nios II, PowerPC).
5513 * Compression Type (uncompressed, gzip, bzip2)
5519 The header is marked by a special Magic Number, and both the header
5520 and the data portions of the image are secured against corruption by
5527 Although U-Boot should support any OS or standalone application
5528 easily, the main focus has always been on Linux during the design of
5531 U-Boot includes many features that so far have been part of some
5532 special "boot loader" code within the Linux kernel. Also, any
5533 "initrd" images to be used are no longer part of one big Linux image;
5534 instead, kernel and "initrd" are separate images. This implementation
5535 serves several purposes:
5537 - the same features can be used for other OS or standalone
5538 applications (for instance: using compressed images to reduce the
5539 Flash memory footprint)
5541 - it becomes much easier to port new Linux kernel versions because
5542 lots of low-level, hardware dependent stuff are done by U-Boot
5544 - the same Linux kernel image can now be used with different "initrd"
5545 images; of course this also means that different kernel images can
5546 be run with the same "initrd". This makes testing easier (you don't
5547 have to build a new "zImage.initrd" Linux image when you just
5548 change a file in your "initrd"). Also, a field-upgrade of the
5549 software is easier now.
5555 Porting Linux to U-Boot based systems:
5556 ---------------------------------------
5558 U-Boot cannot save you from doing all the necessary modifications to
5559 configure the Linux device drivers for use with your target hardware
5560 (no, we don't intend to provide a full virtual machine interface to
5563 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
5565 Just make sure your machine specific header file (for instance
5566 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
5567 Information structure as we define in include/asm-<arch>/u-boot.h,
5568 and make sure that your definition of IMAP_ADDR uses the same value
5569 as your U-Boot configuration in CONFIG_SYS_IMMR.
5571 Note that U-Boot now has a driver model, a unified model for drivers.
5572 If you are adding a new driver, plumb it into driver model. If there
5573 is no uclass available, you are encouraged to create one. See
5577 Configuring the Linux kernel:
5578 -----------------------------
5580 No specific requirements for U-Boot. Make sure you have some root
5581 device (initial ramdisk, NFS) for your target system.
5584 Building a Linux Image:
5585 -----------------------
5587 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
5588 not used. If you use recent kernel source, a new build target
5589 "uImage" will exist which automatically builds an image usable by
5590 U-Boot. Most older kernels also have support for a "pImage" target,
5591 which was introduced for our predecessor project PPCBoot and uses a
5592 100% compatible format.
5596 make TQM850L_defconfig
5601 The "uImage" build target uses a special tool (in 'tools/mkimage') to
5602 encapsulate a compressed Linux kernel image with header information,
5603 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
5605 * build a standard "vmlinux" kernel image (in ELF binary format):
5607 * convert the kernel into a raw binary image:
5609 ${CROSS_COMPILE}-objcopy -O binary \
5610 -R .note -R .comment \
5611 -S vmlinux linux.bin
5613 * compress the binary image:
5617 * package compressed binary image for U-Boot:
5619 mkimage -A ppc -O linux -T kernel -C gzip \
5620 -a 0 -e 0 -n "Linux Kernel Image" \
5621 -d linux.bin.gz uImage
5624 The "mkimage" tool can also be used to create ramdisk images for use
5625 with U-Boot, either separated from the Linux kernel image, or
5626 combined into one file. "mkimage" encapsulates the images with a 64
5627 byte header containing information about target architecture,
5628 operating system, image type, compression method, entry points, time
5629 stamp, CRC32 checksums, etc.
5631 "mkimage" can be called in two ways: to verify existing images and
5632 print the header information, or to build new images.
5634 In the first form (with "-l" option) mkimage lists the information
5635 contained in the header of an existing U-Boot image; this includes
5636 checksum verification:
5638 tools/mkimage -l image
5639 -l ==> list image header information
5641 The second form (with "-d" option) is used to build a U-Boot image
5642 from a "data file" which is used as image payload:
5644 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
5645 -n name -d data_file image
5646 -A ==> set architecture to 'arch'
5647 -O ==> set operating system to 'os'
5648 -T ==> set image type to 'type'
5649 -C ==> set compression type 'comp'
5650 -a ==> set load address to 'addr' (hex)
5651 -e ==> set entry point to 'ep' (hex)
5652 -n ==> set image name to 'name'
5653 -d ==> use image data from 'datafile'
5655 Right now, all Linux kernels for PowerPC systems use the same load
5656 address (0x00000000), but the entry point address depends on the
5659 - 2.2.x kernels have the entry point at 0x0000000C,
5660 - 2.3.x and later kernels have the entry point at 0x00000000.
5662 So a typical call to build a U-Boot image would read:
5664 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5665 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
5666 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
5667 > examples/uImage.TQM850L
5668 Image Name: 2.4.4 kernel for TQM850L
5669 Created: Wed Jul 19 02:34:59 2000
5670 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5671 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5672 Load Address: 0x00000000
5673 Entry Point: 0x00000000
5675 To verify the contents of the image (or check for corruption):
5677 -> tools/mkimage -l examples/uImage.TQM850L
5678 Image Name: 2.4.4 kernel for TQM850L
5679 Created: Wed Jul 19 02:34:59 2000
5680 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5681 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5682 Load Address: 0x00000000
5683 Entry Point: 0x00000000
5685 NOTE: for embedded systems where boot time is critical you can trade
5686 speed for memory and install an UNCOMPRESSED image instead: this
5687 needs more space in Flash, but boots much faster since it does not
5688 need to be uncompressed:
5690 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
5691 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5692 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
5693 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
5694 > examples/uImage.TQM850L-uncompressed
5695 Image Name: 2.4.4 kernel for TQM850L
5696 Created: Wed Jul 19 02:34:59 2000
5697 Image Type: PowerPC Linux Kernel Image (uncompressed)
5698 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
5699 Load Address: 0x00000000
5700 Entry Point: 0x00000000
5703 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
5704 when your kernel is intended to use an initial ramdisk:
5706 -> tools/mkimage -n 'Simple Ramdisk Image' \
5707 > -A ppc -O linux -T ramdisk -C gzip \
5708 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
5709 Image Name: Simple Ramdisk Image
5710 Created: Wed Jan 12 14:01:50 2000
5711 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5712 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
5713 Load Address: 0x00000000
5714 Entry Point: 0x00000000
5716 The "dumpimage" is a tool to disassemble images built by mkimage. Its "-i"
5717 option performs the converse operation of the mkimage's second form (the "-d"
5718 option). Given an image built by mkimage, the dumpimage extracts a "data file"
5721 tools/dumpimage -i image -T type -p position data_file
5722 -i ==> extract from the 'image' a specific 'data_file'
5723 -T ==> set image type to 'type'
5724 -p ==> 'position' (starting at 0) of the 'data_file' inside the 'image'
5727 Installing a Linux Image:
5728 -------------------------
5730 To downloading a U-Boot image over the serial (console) interface,
5731 you must convert the image to S-Record format:
5733 objcopy -I binary -O srec examples/image examples/image.srec
5735 The 'objcopy' does not understand the information in the U-Boot
5736 image header, so the resulting S-Record file will be relative to
5737 address 0x00000000. To load it to a given address, you need to
5738 specify the target address as 'offset' parameter with the 'loads'
5741 Example: install the image to address 0x40100000 (which on the
5742 TQM8xxL is in the first Flash bank):
5744 => erase 40100000 401FFFFF
5750 ## Ready for S-Record download ...
5751 ~>examples/image.srec
5752 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
5754 15989 15990 15991 15992
5755 [file transfer complete]
5757 ## Start Addr = 0x00000000
5760 You can check the success of the download using the 'iminfo' command;
5761 this includes a checksum verification so you can be sure no data
5762 corruption happened:
5766 ## Checking Image at 40100000 ...
5767 Image Name: 2.2.13 for initrd on TQM850L
5768 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5769 Data Size: 335725 Bytes = 327 kB = 0 MB
5770 Load Address: 00000000
5771 Entry Point: 0000000c
5772 Verifying Checksum ... OK
5778 The "bootm" command is used to boot an application that is stored in
5779 memory (RAM or Flash). In case of a Linux kernel image, the contents
5780 of the "bootargs" environment variable is passed to the kernel as
5781 parameters. You can check and modify this variable using the
5782 "printenv" and "setenv" commands:
5785 => printenv bootargs
5786 bootargs=root=/dev/ram
5788 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5790 => printenv bootargs
5791 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5794 ## Booting Linux kernel at 40020000 ...
5795 Image Name: 2.2.13 for NFS on TQM850L
5796 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5797 Data Size: 381681 Bytes = 372 kB = 0 MB
5798 Load Address: 00000000
5799 Entry Point: 0000000c
5800 Verifying Checksum ... OK
5801 Uncompressing Kernel Image ... OK
5802 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
5803 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5804 time_init: decrementer frequency = 187500000/60
5805 Calibrating delay loop... 49.77 BogoMIPS
5806 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
5809 If you want to boot a Linux kernel with initial RAM disk, you pass
5810 the memory addresses of both the kernel and the initrd image (PPBCOOT
5811 format!) to the "bootm" command:
5813 => imi 40100000 40200000
5815 ## Checking Image at 40100000 ...
5816 Image Name: 2.2.13 for initrd on TQM850L
5817 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5818 Data Size: 335725 Bytes = 327 kB = 0 MB
5819 Load Address: 00000000
5820 Entry Point: 0000000c
5821 Verifying Checksum ... OK
5823 ## Checking Image at 40200000 ...
5824 Image Name: Simple Ramdisk Image
5825 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5826 Data Size: 566530 Bytes = 553 kB = 0 MB
5827 Load Address: 00000000
5828 Entry Point: 00000000
5829 Verifying Checksum ... OK
5831 => bootm 40100000 40200000
5832 ## Booting Linux kernel at 40100000 ...
5833 Image Name: 2.2.13 for initrd on TQM850L
5834 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5835 Data Size: 335725 Bytes = 327 kB = 0 MB
5836 Load Address: 00000000
5837 Entry Point: 0000000c
5838 Verifying Checksum ... OK
5839 Uncompressing Kernel Image ... OK
5840 ## Loading RAMDisk Image at 40200000 ...
5841 Image Name: Simple Ramdisk Image
5842 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5843 Data Size: 566530 Bytes = 553 kB = 0 MB
5844 Load Address: 00000000
5845 Entry Point: 00000000
5846 Verifying Checksum ... OK
5847 Loading Ramdisk ... OK
5848 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
5849 Boot arguments: root=/dev/ram
5850 time_init: decrementer frequency = 187500000/60
5851 Calibrating delay loop... 49.77 BogoMIPS
5853 RAMDISK: Compressed image found at block 0
5854 VFS: Mounted root (ext2 filesystem).
5858 Boot Linux and pass a flat device tree:
5861 First, U-Boot must be compiled with the appropriate defines. See the section
5862 titled "Linux Kernel Interface" above for a more in depth explanation. The
5863 following is an example of how to start a kernel and pass an updated
5869 oft=oftrees/mpc8540ads.dtb
5870 => tftp $oftaddr $oft
5871 Speed: 1000, full duplex
5873 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
5874 Filename 'oftrees/mpc8540ads.dtb'.
5875 Load address: 0x300000
5878 Bytes transferred = 4106 (100a hex)
5879 => tftp $loadaddr $bootfile
5880 Speed: 1000, full duplex
5882 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
5884 Load address: 0x200000
5885 Loading:############
5887 Bytes transferred = 1029407 (fb51f hex)
5892 => bootm $loadaddr - $oftaddr
5893 ## Booting image at 00200000 ...
5894 Image Name: Linux-2.6.17-dirty
5895 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5896 Data Size: 1029343 Bytes = 1005.2 kB
5897 Load Address: 00000000
5898 Entry Point: 00000000
5899 Verifying Checksum ... OK
5900 Uncompressing Kernel Image ... OK
5901 Booting using flat device tree at 0x300000
5902 Using MPC85xx ADS machine description
5903 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
5907 More About U-Boot Image Types:
5908 ------------------------------
5910 U-Boot supports the following image types:
5912 "Standalone Programs" are directly runnable in the environment
5913 provided by U-Boot; it is expected that (if they behave
5914 well) you can continue to work in U-Boot after return from
5915 the Standalone Program.
5916 "OS Kernel Images" are usually images of some Embedded OS which
5917 will take over control completely. Usually these programs
5918 will install their own set of exception handlers, device
5919 drivers, set up the MMU, etc. - this means, that you cannot
5920 expect to re-enter U-Boot except by resetting the CPU.
5921 "RAMDisk Images" are more or less just data blocks, and their
5922 parameters (address, size) are passed to an OS kernel that is
5924 "Multi-File Images" contain several images, typically an OS
5925 (Linux) kernel image and one or more data images like
5926 RAMDisks. This construct is useful for instance when you want
5927 to boot over the network using BOOTP etc., where the boot
5928 server provides just a single image file, but you want to get
5929 for instance an OS kernel and a RAMDisk image.
5931 "Multi-File Images" start with a list of image sizes, each
5932 image size (in bytes) specified by an "uint32_t" in network
5933 byte order. This list is terminated by an "(uint32_t)0".
5934 Immediately after the terminating 0 follow the images, one by
5935 one, all aligned on "uint32_t" boundaries (size rounded up to
5936 a multiple of 4 bytes).
5938 "Firmware Images" are binary images containing firmware (like
5939 U-Boot or FPGA images) which usually will be programmed to
5942 "Script files" are command sequences that will be executed by
5943 U-Boot's command interpreter; this feature is especially
5944 useful when you configure U-Boot to use a real shell (hush)
5945 as command interpreter.
5947 Booting the Linux zImage:
5948 -------------------------
5950 On some platforms, it's possible to boot Linux zImage. This is done
5951 using the "bootz" command. The syntax of "bootz" command is the same
5952 as the syntax of "bootm" command.
5954 Note, defining the CONFIG_SUPPORT_RAW_INITRD allows user to supply
5955 kernel with raw initrd images. The syntax is slightly different, the
5956 address of the initrd must be augmented by it's size, in the following
5957 format: "<initrd addres>:<initrd size>".
5963 One of the features of U-Boot is that you can dynamically load and
5964 run "standalone" applications, which can use some resources of
5965 U-Boot like console I/O functions or interrupt services.
5967 Two simple examples are included with the sources:
5972 'examples/hello_world.c' contains a small "Hello World" Demo
5973 application; it is automatically compiled when you build U-Boot.
5974 It's configured to run at address 0x00040004, so you can play with it
5978 ## Ready for S-Record download ...
5979 ~>examples/hello_world.srec
5980 1 2 3 4 5 6 7 8 9 10 11 ...
5981 [file transfer complete]
5983 ## Start Addr = 0x00040004
5985 => go 40004 Hello World! This is a test.
5986 ## Starting application at 0x00040004 ...
5997 Hit any key to exit ...
5999 ## Application terminated, rc = 0x0
6001 Another example, which demonstrates how to register a CPM interrupt
6002 handler with the U-Boot code, can be found in 'examples/timer.c'.
6003 Here, a CPM timer is set up to generate an interrupt every second.
6004 The interrupt service routine is trivial, just printing a '.'
6005 character, but this is just a demo program. The application can be
6006 controlled by the following keys:
6008 ? - print current values og the CPM Timer registers
6009 b - enable interrupts and start timer
6010 e - stop timer and disable interrupts
6011 q - quit application
6014 ## Ready for S-Record download ...
6015 ~>examples/timer.srec
6016 1 2 3 4 5 6 7 8 9 10 11 ...
6017 [file transfer complete]
6019 ## Start Addr = 0x00040004
6022 ## Starting application at 0x00040004 ...
6025 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
6028 [q, b, e, ?] Set interval 1000000 us
6031 [q, b, e, ?] ........
6032 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
6035 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
6038 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
6041 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
6043 [q, b, e, ?] ...Stopping timer
6045 [q, b, e, ?] ## Application terminated, rc = 0x0
6051 Over time, many people have reported problems when trying to use the
6052 "minicom" terminal emulation program for serial download. I (wd)
6053 consider minicom to be broken, and recommend not to use it. Under
6054 Unix, I recommend to use C-Kermit for general purpose use (and
6055 especially for kermit binary protocol download ("loadb" command), and
6056 use "cu" for S-Record download ("loads" command). See
6057 http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
6058 for help with kermit.
6061 Nevertheless, if you absolutely want to use it try adding this
6062 configuration to your "File transfer protocols" section:
6064 Name Program Name U/D FullScr IO-Red. Multi
6065 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
6066 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
6072 Starting at version 0.9.2, U-Boot supports NetBSD both as host
6073 (build U-Boot) and target system (boots NetBSD/mpc8xx).
6075 Building requires a cross environment; it is known to work on
6076 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
6077 need gmake since the Makefiles are not compatible with BSD make).
6078 Note that the cross-powerpc package does not install include files;
6079 attempting to build U-Boot will fail because <machine/ansi.h> is
6080 missing. This file has to be installed and patched manually:
6082 # cd /usr/pkg/cross/powerpc-netbsd/include
6084 # ln -s powerpc machine
6085 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
6086 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
6088 Native builds *don't* work due to incompatibilities between native
6089 and U-Boot include files.
6091 Booting assumes that (the first part of) the image booted is a
6092 stage-2 loader which in turn loads and then invokes the kernel
6093 proper. Loader sources will eventually appear in the NetBSD source
6094 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
6095 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
6098 Implementation Internals:
6099 =========================
6101 The following is not intended to be a complete description of every
6102 implementation detail. However, it should help to understand the
6103 inner workings of U-Boot and make it easier to port it to custom
6107 Initial Stack, Global Data:
6108 ---------------------------
6110 The implementation of U-Boot is complicated by the fact that U-Boot
6111 starts running out of ROM (flash memory), usually without access to
6112 system RAM (because the memory controller is not initialized yet).
6113 This means that we don't have writable Data or BSS segments, and BSS
6114 is not initialized as zero. To be able to get a C environment working
6115 at all, we have to allocate at least a minimal stack. Implementation
6116 options for this are defined and restricted by the CPU used: Some CPU
6117 models provide on-chip memory (like the IMMR area on MPC8xx and
6118 MPC826x processors), on others (parts of) the data cache can be
6119 locked as (mis-) used as memory, etc.
6121 Chris Hallinan posted a good summary of these issues to the
6122 U-Boot mailing list:
6124 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
6125 From: "Chris Hallinan" <clh@net1plus.com>
6126 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
6129 Correct me if I'm wrong, folks, but the way I understand it
6130 is this: Using DCACHE as initial RAM for Stack, etc, does not
6131 require any physical RAM backing up the cache. The cleverness
6132 is that the cache is being used as a temporary supply of
6133 necessary storage before the SDRAM controller is setup. It's
6134 beyond the scope of this list to explain the details, but you
6135 can see how this works by studying the cache architecture and
6136 operation in the architecture and processor-specific manuals.
6138 OCM is On Chip Memory, which I believe the 405GP has 4K. It
6139 is another option for the system designer to use as an
6140 initial stack/RAM area prior to SDRAM being available. Either
6141 option should work for you. Using CS 4 should be fine if your
6142 board designers haven't used it for something that would
6143 cause you grief during the initial boot! It is frequently not
6146 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
6147 with your processor/board/system design. The default value
6148 you will find in any recent u-boot distribution in
6149 walnut.h should work for you. I'd set it to a value larger
6150 than your SDRAM module. If you have a 64MB SDRAM module, set
6151 it above 400_0000. Just make sure your board has no resources
6152 that are supposed to respond to that address! That code in
6153 start.S has been around a while and should work as is when
6154 you get the config right.
6159 It is essential to remember this, since it has some impact on the C
6160 code for the initialization procedures:
6162 * Initialized global data (data segment) is read-only. Do not attempt
6165 * Do not use any uninitialized global data (or implicitly initialized
6166 as zero data - BSS segment) at all - this is undefined, initiali-
6167 zation is performed later (when relocating to RAM).
6169 * Stack space is very limited. Avoid big data buffers or things like
6172 Having only the stack as writable memory limits means we cannot use
6173 normal global data to share information between the code. But it
6174 turned out that the implementation of U-Boot can be greatly
6175 simplified by making a global data structure (gd_t) available to all
6176 functions. We could pass a pointer to this data as argument to _all_
6177 functions, but this would bloat the code. Instead we use a feature of
6178 the GCC compiler (Global Register Variables) to share the data: we
6179 place a pointer (gd) to the global data into a register which we
6180 reserve for this purpose.
6182 When choosing a register for such a purpose we are restricted by the
6183 relevant (E)ABI specifications for the current architecture, and by
6184 GCC's implementation.
6186 For PowerPC, the following registers have specific use:
6188 R2: reserved for system use
6189 R3-R4: parameter passing and return values
6190 R5-R10: parameter passing
6191 R13: small data area pointer
6195 (U-Boot also uses R12 as internal GOT pointer. r12
6196 is a volatile register so r12 needs to be reset when
6197 going back and forth between asm and C)
6199 ==> U-Boot will use R2 to hold a pointer to the global data
6201 Note: on PPC, we could use a static initializer (since the
6202 address of the global data structure is known at compile time),
6203 but it turned out that reserving a register results in somewhat
6204 smaller code - although the code savings are not that big (on
6205 average for all boards 752 bytes for the whole U-Boot image,
6206 624 text + 127 data).
6208 On Blackfin, the normal C ABI (except for P3) is followed as documented here:
6209 http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
6211 ==> U-Boot will use P3 to hold a pointer to the global data
6213 On ARM, the following registers are used:
6215 R0: function argument word/integer result
6216 R1-R3: function argument word
6217 R9: platform specific
6218 R10: stack limit (used only if stack checking is enabled)
6219 R11: argument (frame) pointer
6220 R12: temporary workspace
6223 R15: program counter
6225 ==> U-Boot will use R9 to hold a pointer to the global data
6227 Note: on ARM, only R_ARM_RELATIVE relocations are supported.
6229 On Nios II, the ABI is documented here:
6230 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
6232 ==> U-Boot will use gp to hold a pointer to the global data
6234 Note: on Nios II, we give "-G0" option to gcc and don't use gp
6235 to access small data sections, so gp is free.
6237 On NDS32, the following registers are used:
6239 R0-R1: argument/return
6241 R15: temporary register for assembler
6242 R16: trampoline register
6243 R28: frame pointer (FP)
6244 R29: global pointer (GP)
6245 R30: link register (LP)
6246 R31: stack pointer (SP)
6247 PC: program counter (PC)
6249 ==> U-Boot will use R10 to hold a pointer to the global data
6251 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
6252 or current versions of GCC may "optimize" the code too much.
6257 U-Boot runs in system state and uses physical addresses, i.e. the
6258 MMU is not used either for address mapping nor for memory protection.
6260 The available memory is mapped to fixed addresses using the memory
6261 controller. In this process, a contiguous block is formed for each
6262 memory type (Flash, SDRAM, SRAM), even when it consists of several
6263 physical memory banks.
6265 U-Boot is installed in the first 128 kB of the first Flash bank (on
6266 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
6267 booting and sizing and initializing DRAM, the code relocates itself
6268 to the upper end of DRAM. Immediately below the U-Boot code some
6269 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
6270 configuration setting]. Below that, a structure with global Board
6271 Info data is placed, followed by the stack (growing downward).
6273 Additionally, some exception handler code is copied to the low 8 kB
6274 of DRAM (0x00000000 ... 0x00001FFF).
6276 So a typical memory configuration with 16 MB of DRAM could look like
6279 0x0000 0000 Exception Vector code
6282 0x0000 2000 Free for Application Use
6288 0x00FB FF20 Monitor Stack (Growing downward)
6289 0x00FB FFAC Board Info Data and permanent copy of global data
6290 0x00FC 0000 Malloc Arena
6293 0x00FE 0000 RAM Copy of Monitor Code
6294 ... eventually: LCD or video framebuffer
6295 ... eventually: pRAM (Protected RAM - unchanged by reset)
6296 0x00FF FFFF [End of RAM]
6299 System Initialization:
6300 ----------------------
6302 In the reset configuration, U-Boot starts at the reset entry point
6303 (on most PowerPC systems at address 0x00000100). Because of the reset
6304 configuration for CS0# this is a mirror of the on board Flash memory.
6305 To be able to re-map memory U-Boot then jumps to its link address.
6306 To be able to implement the initialization code in C, a (small!)
6307 initial stack is set up in the internal Dual Ported RAM (in case CPUs
6308 which provide such a feature like MPC8xx or MPC8260), or in a locked
6309 part of the data cache. After that, U-Boot initializes the CPU core,
6310 the caches and the SIU.
6312 Next, all (potentially) available memory banks are mapped using a
6313 preliminary mapping. For example, we put them on 512 MB boundaries
6314 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
6315 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
6316 programmed for SDRAM access. Using the temporary configuration, a
6317 simple memory test is run that determines the size of the SDRAM
6320 When there is more than one SDRAM bank, and the banks are of
6321 different size, the largest is mapped first. For equal size, the first
6322 bank (CS2#) is mapped first. The first mapping is always for address
6323 0x00000000, with any additional banks following immediately to create
6324 contiguous memory starting from 0.
6326 Then, the monitor installs itself at the upper end of the SDRAM area
6327 and allocates memory for use by malloc() and for the global Board
6328 Info data; also, the exception vector code is copied to the low RAM
6329 pages, and the final stack is set up.
6331 Only after this relocation will you have a "normal" C environment;
6332 until that you are restricted in several ways, mostly because you are
6333 running from ROM, and because the code will have to be relocated to a
6337 U-Boot Porting Guide:
6338 ----------------------
6340 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
6344 int main(int argc, char *argv[])
6346 sighandler_t no_more_time;
6348 signal(SIGALRM, no_more_time);
6349 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
6351 if (available_money > available_manpower) {
6352 Pay consultant to port U-Boot;
6356 Download latest U-Boot source;
6358 Subscribe to u-boot mailing list;
6361 email("Hi, I am new to U-Boot, how do I get started?");
6364 Read the README file in the top level directory;
6365 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
6366 Read applicable doc/*.README;
6367 Read the source, Luke;
6368 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
6371 if (available_money > toLocalCurrency ($2500))
6374 Add a lot of aggravation and time;
6376 if (a similar board exists) { /* hopefully... */
6377 cp -a board/<similar> board/<myboard>
6378 cp include/configs/<similar>.h include/configs/<myboard>.h
6380 Create your own board support subdirectory;
6381 Create your own board include/configs/<myboard>.h file;
6383 Edit new board/<myboard> files
6384 Edit new include/configs/<myboard>.h
6389 Add / modify source code;
6393 email("Hi, I am having problems...");
6395 Send patch file to the U-Boot email list;
6396 if (reasonable critiques)
6397 Incorporate improvements from email list code review;
6399 Defend code as written;
6405 void no_more_time (int sig)
6414 All contributions to U-Boot should conform to the Linux kernel
6415 coding style; see the file "Documentation/CodingStyle" and the script
6416 "scripts/Lindent" in your Linux kernel source directory.
6418 Source files originating from a different project (for example the
6419 MTD subsystem) are generally exempt from these guidelines and are not
6420 reformatted to ease subsequent migration to newer versions of those
6423 Please note that U-Boot is implemented in C (and to some small parts in
6424 Assembler); no C++ is used, so please do not use C++ style comments (//)
6427 Please also stick to the following formatting rules:
6428 - remove any trailing white space
6429 - use TAB characters for indentation and vertical alignment, not spaces
6430 - make sure NOT to use DOS '\r\n' line feeds
6431 - do not add more than 2 consecutive empty lines to source files
6432 - do not add trailing empty lines to source files
6434 Submissions which do not conform to the standards may be returned
6435 with a request to reformat the changes.
6441 Since the number of patches for U-Boot is growing, we need to
6442 establish some rules. Submissions which do not conform to these rules
6443 may be rejected, even when they contain important and valuable stuff.
6445 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
6447 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
6448 see http://lists.denx.de/mailman/listinfo/u-boot
6450 When you send a patch, please include the following information with
6453 * For bug fixes: a description of the bug and how your patch fixes
6454 this bug. Please try to include a way of demonstrating that the
6455 patch actually fixes something.
6457 * For new features: a description of the feature and your
6460 * A CHANGELOG entry as plaintext (separate from the patch)
6462 * For major contributions, add a MAINTAINERS file with your
6463 information and associated file and directory references.
6465 * When you add support for a new board, don't forget to add a
6466 maintainer e-mail address to the boards.cfg file, too.
6468 * If your patch adds new configuration options, don't forget to
6469 document these in the README file.
6471 * The patch itself. If you are using git (which is *strongly*
6472 recommended) you can easily generate the patch using the
6473 "git format-patch". If you then use "git send-email" to send it to
6474 the U-Boot mailing list, you will avoid most of the common problems
6475 with some other mail clients.
6477 If you cannot use git, use "diff -purN OLD NEW". If your version of
6478 diff does not support these options, then get the latest version of
6481 The current directory when running this command shall be the parent
6482 directory of the U-Boot source tree (i. e. please make sure that
6483 your patch includes sufficient directory information for the
6486 We prefer patches as plain text. MIME attachments are discouraged,
6487 and compressed attachments must not be used.
6489 * If one logical set of modifications affects or creates several
6490 files, all these changes shall be submitted in a SINGLE patch file.
6492 * Changesets that contain different, unrelated modifications shall be
6493 submitted as SEPARATE patches, one patch per changeset.
6498 * Before sending the patch, run the buildman script on your patched
6499 source tree and make sure that no errors or warnings are reported
6500 for any of the boards.
6502 * Keep your modifications to the necessary minimum: A patch
6503 containing several unrelated changes or arbitrary reformats will be
6504 returned with a request to re-formatting / split it.
6506 * If you modify existing code, make sure that your new code does not
6507 add to the memory footprint of the code ;-) Small is beautiful!
6508 When adding new features, these should compile conditionally only
6509 (using #ifdef), and the resulting code with the new feature
6510 disabled must not need more memory than the old code without your
6513 * Remember that there is a size limit of 100 kB per message on the
6514 u-boot mailing list. Bigger patches will be moderated. If they are
6515 reasonable and not too big, they will be acknowledged. But patches
6516 bigger than the size limit should be avoided.
projects / platform / kernel / u-boot.git / blob