2 # (C) Copyright 2000 - 2013
3 # Wolfgang Denk, DENX Software Engineering, wd@denx.de.
5 # SPDX-License-Identifier: GPL-2.0+
11 This directory contains the source code for U-Boot, a boot loader for
12 Embedded boards based on PowerPC, ARM, MIPS and several other
13 processors, which can be installed in a boot ROM and used to
14 initialize and test the hardware or to download and run application
17 The development of U-Boot is closely related to Linux: some parts of
18 the source code originate in the Linux source tree, we have some
19 header files in common, and special provision has been made to
20 support booting of Linux images.
22 Some attention has been paid to make this software easily
23 configurable and extendable. For instance, all monitor commands are
24 implemented with the same call interface, so that it's very easy to
25 add new commands. Also, instead of permanently adding rarely used
26 code (for instance hardware test utilities) to the monitor, you can
27 load and run it dynamically.
33 In general, all boards for which a configuration option exists in the
34 Makefile have been tested to some extent and can be considered
35 "working". In fact, many of them are used in production systems.
37 In case of problems see the CHANGELOG file to find out who contributed
38 the specific port. In addition, there are various MAINTAINERS files
39 scattered throughout the U-Boot source identifying the people or
40 companies responsible for various boards and subsystems.
42 Note: As of August, 2010, there is no longer a CHANGELOG file in the
43 actual U-Boot source tree; however, it can be created dynamically
44 from the Git log using:
52 In case you have questions about, problems with or contributions for
53 U-Boot, you should send a message to the U-Boot mailing list at
54 <u-boot@lists.denx.de>. There is also an archive of previous traffic
55 on the mailing list - please search the archive before asking FAQ's.
56 Please see http://lists.denx.de/pipermail/u-boot and
57 http://dir.gmane.org/gmane.comp.boot-loaders.u-boot
60 Where to get source code:
61 =========================
63 The U-Boot source code is maintained in the Git repository at
64 git://www.denx.de/git/u-boot.git ; you can browse it online at
65 http://www.denx.de/cgi-bin/gitweb.cgi?p=u-boot.git;a=summary
67 The "snapshot" links on this page allow you to download tarballs of
68 any version you might be interested in. Official releases are also
69 available for FTP download from the ftp://ftp.denx.de/pub/u-boot/
72 Pre-built (and tested) images are available from
73 ftp://ftp.denx.de/pub/u-boot/images/
79 - start from 8xxrom sources
80 - create PPCBoot project (http://sourceforge.net/projects/ppcboot)
82 - make it easier to add custom boards
83 - make it possible to add other [PowerPC] CPUs
84 - extend functions, especially:
85 * Provide extended interface to Linux boot loader
88 * PCMCIA / CompactFlash / ATA disk / SCSI ... boot
89 - create ARMBoot project (http://sourceforge.net/projects/armboot)
90 - add other CPU families (starting with ARM)
91 - create U-Boot project (http://sourceforge.net/projects/u-boot)
92 - current project page: see http://www.denx.de/wiki/U-Boot
98 The "official" name of this project is "Das U-Boot". The spelling
99 "U-Boot" shall be used in all written text (documentation, comments
100 in source files etc.). Example:
102 This is the README file for the U-Boot project.
104 File names etc. shall be based on the string "u-boot". Examples:
106 include/asm-ppc/u-boot.h
108 #include <asm/u-boot.h>
110 Variable names, preprocessor constants etc. shall be either based on
111 the string "u_boot" or on "U_BOOT". Example:
113 U_BOOT_VERSION u_boot_logo
114 IH_OS_U_BOOT u_boot_hush_start
120 Starting with the release in October 2008, the names of the releases
121 were changed from numerical release numbers without deeper meaning
122 into a time stamp based numbering. Regular releases are identified by
123 names consisting of the calendar year and month of the release date.
124 Additional fields (if present) indicate release candidates or bug fix
125 releases in "stable" maintenance trees.
128 U-Boot v2009.11 - Release November 2009
129 U-Boot v2009.11.1 - Release 1 in version November 2009 stable tree
130 U-Boot v2010.09-rc1 - Release candidate 1 for September 2010 release
136 /arch Architecture specific files
137 /arc Files generic to ARC architecture
138 /arm Files generic to ARM architecture
139 /avr32 Files generic to AVR32 architecture
140 /m68k Files generic to m68k architecture
141 /microblaze Files generic to microblaze architecture
142 /mips Files generic to MIPS architecture
143 /nds32 Files generic to NDS32 architecture
144 /nios2 Files generic to Altera NIOS2 architecture
145 /openrisc Files generic to OpenRISC architecture
146 /powerpc Files generic to PowerPC architecture
147 /sandbox Files generic to HW-independent "sandbox"
148 /sh Files generic to SH architecture
149 /x86 Files generic to x86 architecture
150 /api Machine/arch independent API for external apps
151 /board Board dependent files
152 /cmd U-Boot commands functions
153 /common Misc architecture independent functions
154 /configs Board default configuration files
155 /disk Code for disk drive partition handling
156 /doc Documentation (don't expect too much)
157 /drivers Commonly used device drivers
158 /dts Contains Makefile for building internal U-Boot fdt.
159 /examples Example code for standalone applications, etc.
160 /fs Filesystem code (cramfs, ext2, jffs2, etc.)
161 /include Header Files
162 /lib Library routines generic to all architectures
163 /Licenses Various license files
165 /post Power On Self Test
166 /scripts Various build scripts and Makefiles
167 /test Various unit test files
168 /tools Tools to build S-Record or U-Boot images, etc.
170 Software Configuration:
171 =======================
173 Configuration is usually done using C preprocessor defines; the
174 rationale behind that is to avoid dead code whenever possible.
176 There are two classes of configuration variables:
178 * Configuration _OPTIONS_:
179 These are selectable by the user and have names beginning with
182 * Configuration _SETTINGS_:
183 These depend on the hardware etc. and should not be meddled with if
184 you don't know what you're doing; they have names beginning with
187 Previously, all configuration was done by hand, which involved creating
188 symbolic links and editing configuration files manually. More recently,
189 U-Boot has added the Kbuild infrastructure used by the Linux kernel,
190 allowing you to use the "make menuconfig" command to configure your
194 Selection of Processor Architecture and Board Type:
195 ---------------------------------------------------
197 For all supported boards there are ready-to-use default
198 configurations available; just type "make <board_name>_defconfig".
200 Example: For a TQM823L module type:
203 make TQM823L_defconfig
205 Note: If you're looking for the default configuration file for a board
206 you're sure used to be there but is now missing, check the file
207 doc/README.scrapyard for a list of no longer supported boards.
212 U-Boot can be built natively to run on a Linux host using the 'sandbox'
213 board. This allows feature development which is not board- or architecture-
214 specific to be undertaken on a native platform. The sandbox is also used to
215 run some of U-Boot's tests.
217 See board/sandbox/README.sandbox for more details.
220 Board Initialisation Flow:
221 --------------------------
223 This is the intended start-up flow for boards. This should apply for both
224 SPL and U-Boot proper (i.e. they both follow the same rules).
226 Note: "SPL" stands for "Secondary Program Loader," which is explained in
227 more detail later in this file.
229 At present, SPL mostly uses a separate code path, but the function names
230 and roles of each function are the same. Some boards or architectures
231 may not conform to this. At least most ARM boards which use
232 CONFIG_SPL_FRAMEWORK conform to this.
234 Execution typically starts with an architecture-specific (and possibly
235 CPU-specific) start.S file, such as:
237 - arch/arm/cpu/armv7/start.S
238 - arch/powerpc/cpu/mpc83xx/start.S
239 - arch/mips/cpu/start.S
241 and so on. From there, three functions are called; the purpose and
242 limitations of each of these functions are described below.
245 - purpose: essential init to permit execution to reach board_init_f()
246 - no global_data or BSS
247 - there is no stack (ARMv7 may have one but it will soon be removed)
248 - must not set up SDRAM or use console
249 - must only do the bare minimum to allow execution to continue to
251 - this is almost never needed
252 - return normally from this function
255 - purpose: set up the machine ready for running board_init_r():
256 i.e. SDRAM and serial UART
257 - global_data is available
259 - BSS is not available, so you cannot use global/static variables,
260 only stack variables and global_data
262 Non-SPL-specific notes:
263 - dram_init() is called to set up DRAM. If already done in SPL this
267 - you can override the entire board_init_f() function with your own
269 - preloader_console_init() can be called here in extremis
270 - should set up SDRAM, and anything needed to make the UART work
271 - these is no need to clear BSS, it will be done by crt0.S
272 - must return normally from this function (don't call board_init_r()
275 Here the BSS is cleared. For SPL, if CONFIG_SPL_STACK_R is defined, then at
276 this point the stack and global_data are relocated to below
277 CONFIG_SPL_STACK_R_ADDR. For non-SPL, U-Boot is relocated to run at the top of
281 - purpose: main execution, common code
282 - global_data is available
284 - BSS is available, all static/global variables can be used
285 - execution eventually continues to main_loop()
287 Non-SPL-specific notes:
288 - U-Boot is relocated to the top of memory and is now running from
292 - stack is optionally in SDRAM, if CONFIG_SPL_STACK_R is defined and
293 CONFIG_SPL_STACK_R_ADDR points into SDRAM
294 - preloader_console_init() can be called here - typically this is
295 done by selecting CONFIG_SPL_BOARD_INIT and then supplying a
296 spl_board_init() function containing this call
297 - loads U-Boot or (in falcon mode) Linux
301 Configuration Options:
302 ----------------------
304 Configuration depends on the combination of board and CPU type; all
305 such information is kept in a configuration file
306 "include/configs/<board_name>.h".
308 Example: For a TQM823L module, all configuration settings are in
309 "include/configs/TQM823L.h".
312 Many of the options are named exactly as the corresponding Linux
313 kernel configuration options. The intention is to make it easier to
314 build a config tool - later.
317 The following options need to be configured:
319 - CPU Type: Define exactly one, e.g. CONFIG_MPC85XX.
321 - Board Type: Define exactly one, e.g. CONFIG_MPC8540ADS.
323 - CPU Daughterboard Type: (if CONFIG_ATSTK1000 is defined)
324 Define exactly one, e.g. CONFIG_ATSTK1002
326 - Marvell Family Member
327 CONFIG_SYS_MVFS - define it if you want to enable
328 multiple fs option at one time
329 for marvell soc family
331 - 8xx CPU Options: (if using an MPC8xx CPU)
332 CONFIG_8xx_GCLK_FREQ - deprecated: CPU clock if
333 get_gclk_freq() cannot work
334 e.g. if there is no 32KHz
335 reference PIT/RTC clock
336 CONFIG_8xx_OSCLK - PLL input clock (either EXTCLK
339 - 859/866/885 CPU options: (if using a MPC859 or MPC866 or MPC885 CPU):
340 CONFIG_SYS_8xx_CPUCLK_MIN
341 CONFIG_SYS_8xx_CPUCLK_MAX
342 CONFIG_8xx_CPUCLK_DEFAULT
343 See doc/README.MPC866
345 CONFIG_SYS_MEASURE_CPUCLK
347 Define this to measure the actual CPU clock instead
348 of relying on the correctness of the configured
349 values. Mostly useful for board bringup to make sure
350 the PLL is locked at the intended frequency. Note
351 that this requires a (stable) reference clock (32 kHz
352 RTC clock or CONFIG_SYS_8XX_XIN)
354 CONFIG_SYS_DELAYED_ICACHE
356 Define this option if you want to enable the
357 ICache only when Code runs from RAM.
362 Specifies that the core is a 64-bit PowerPC implementation (implements
363 the "64" category of the Power ISA). This is necessary for ePAPR
364 compliance, among other possible reasons.
366 CONFIG_SYS_FSL_TBCLK_DIV
368 Defines the core time base clock divider ratio compared to the
369 system clock. On most PQ3 devices this is 8, on newer QorIQ
370 devices it can be 16 or 32. The ratio varies from SoC to Soc.
372 CONFIG_SYS_FSL_PCIE_COMPAT
374 Defines the string to utilize when trying to match PCIe device
375 tree nodes for the given platform.
377 CONFIG_SYS_FSL_ERRATUM_A004510
379 Enables a workaround for erratum A004510. If set,
380 then CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV and
381 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY must be set.
383 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV
384 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV2 (optional)
386 Defines one or two SoC revisions (low 8 bits of SVR)
387 for which the A004510 workaround should be applied.
389 The rest of SVR is either not relevant to the decision
390 of whether the erratum is present (e.g. p2040 versus
391 p2041) or is implied by the build target, which controls
392 whether CONFIG_SYS_FSL_ERRATUM_A004510 is set.
394 See Freescale App Note 4493 for more information about
397 CONFIG_A003399_NOR_WORKAROUND
398 Enables a workaround for IFC erratum A003399. It is only
399 required during NOR boot.
401 CONFIG_A008044_WORKAROUND
402 Enables a workaround for T1040/T1042 erratum A008044. It is only
403 required during NAND boot and valid for Rev 1.0 SoC revision
405 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY
407 This is the value to write into CCSR offset 0x18600
408 according to the A004510 workaround.
410 CONFIG_SYS_FSL_DSP_DDR_ADDR
411 This value denotes start offset of DDR memory which is
412 connected exclusively to the DSP cores.
414 CONFIG_SYS_FSL_DSP_M2_RAM_ADDR
415 This value denotes start offset of M2 memory
416 which is directly connected to the DSP core.
418 CONFIG_SYS_FSL_DSP_M3_RAM_ADDR
419 This value denotes start offset of M3 memory which is directly
420 connected to the DSP core.
422 CONFIG_SYS_FSL_DSP_CCSRBAR_DEFAULT
423 This value denotes start offset of DSP CCSR space.
425 CONFIG_SYS_FSL_SINGLE_SOURCE_CLK
426 Single Source Clock is clocking mode present in some of FSL SoC's.
427 In this mode, a single differential clock is used to supply
428 clocks to the sysclock, ddrclock and usbclock.
430 CONFIG_SYS_CPC_REINIT_F
431 This CONFIG is defined when the CPC is configured as SRAM at the
432 time of U-Boot entry and is required to be re-initialized.
435 Indicates this SoC supports deep sleep feature. If deep sleep is
436 supported, core will start to execute uboot when wakes up.
438 - Generic CPU options:
439 CONFIG_SYS_GENERIC_GLOBAL_DATA
440 Defines global data is initialized in generic board board_init_f().
441 If this macro is defined, global data is created and cleared in
442 generic board board_init_f(). Without this macro, architecture/board
443 should initialize global data before calling board_init_f().
445 CONFIG_SYS_BIG_ENDIAN, CONFIG_SYS_LITTLE_ENDIAN
447 Defines the endianess of the CPU. Implementation of those
448 values is arch specific.
451 Freescale DDR driver in use. This type of DDR controller is
452 found in mpc83xx, mpc85xx, mpc86xx as well as some ARM core
455 CONFIG_SYS_FSL_DDR_ADDR
456 Freescale DDR memory-mapped register base.
458 CONFIG_SYS_FSL_DDR_EMU
459 Specify emulator support for DDR. Some DDR features such as
460 deskew training are not available.
462 CONFIG_SYS_FSL_DDRC_GEN1
463 Freescale DDR1 controller.
465 CONFIG_SYS_FSL_DDRC_GEN2
466 Freescale DDR2 controller.
468 CONFIG_SYS_FSL_DDRC_GEN3
469 Freescale DDR3 controller.
471 CONFIG_SYS_FSL_DDRC_GEN4
472 Freescale DDR4 controller.
474 CONFIG_SYS_FSL_DDRC_ARM_GEN3
475 Freescale DDR3 controller for ARM-based SoCs.
478 Board config to use DDR1. It can be enabled for SoCs with
479 Freescale DDR1 or DDR2 controllers, depending on the board
483 Board config to use DDR2. It can be enabled for SoCs with
484 Freescale DDR2 or DDR3 controllers, depending on the board
488 Board config to use DDR3. It can be enabled for SoCs with
489 Freescale DDR3 or DDR3L controllers.
492 Board config to use DDR3L. It can be enabled for SoCs with
496 Board config to use DDR4. It can be enabled for SoCs with
499 CONFIG_SYS_FSL_IFC_BE
500 Defines the IFC controller register space as Big Endian
502 CONFIG_SYS_FSL_IFC_LE
503 Defines the IFC controller register space as Little Endian
505 CONFIG_SYS_FSL_IFC_CLK_DIV
506 Defines divider of platform clock(clock input to IFC controller).
508 CONFIG_SYS_FSL_LBC_CLK_DIV
509 Defines divider of platform clock(clock input to eLBC controller).
511 CONFIG_SYS_FSL_PBL_PBI
512 It enables addition of RCW (Power on reset configuration) in built image.
513 Please refer doc/README.pblimage for more details
515 CONFIG_SYS_FSL_PBL_RCW
516 It adds PBI(pre-boot instructions) commands in u-boot build image.
517 PBI commands can be used to configure SoC before it starts the execution.
518 Please refer doc/README.pblimage for more details
521 It adds a target to create boot binary having SPL binary in PBI format
522 concatenated with u-boot binary.
524 CONFIG_SYS_FSL_DDR_BE
525 Defines the DDR controller register space as Big Endian
527 CONFIG_SYS_FSL_DDR_LE
528 Defines the DDR controller register space as Little Endian
530 CONFIG_SYS_FSL_DDR_SDRAM_BASE_PHY
531 Physical address from the view of DDR controllers. It is the
532 same as CONFIG_SYS_DDR_SDRAM_BASE for all Power SoCs. But
533 it could be different for ARM SoCs.
535 CONFIG_SYS_FSL_DDR_INTLV_256B
536 DDR controller interleaving on 256-byte. This is a special
537 interleaving mode, handled by Dickens for Freescale layerscape
540 CONFIG_SYS_FSL_DDR_MAIN_NUM_CTRLS
541 Number of controllers used as main memory.
543 CONFIG_SYS_FSL_OTHER_DDR_NUM_CTRLS
544 Number of controllers used for other than main memory.
546 CONFIG_SYS_FSL_HAS_DP_DDR
547 Defines the SoC has DP-DDR used for DPAA.
549 CONFIG_SYS_FSL_SEC_BE
550 Defines the SEC controller register space as Big Endian
552 CONFIG_SYS_FSL_SEC_LE
553 Defines the SEC controller register space as Little Endian
556 CONFIG_SYS_INIT_SP_OFFSET
558 Offset relative to CONFIG_SYS_SDRAM_BASE for initial stack
559 pointer. This is needed for the temporary stack before
562 CONFIG_SYS_MIPS_CACHE_MODE
564 Cache operation mode for the MIPS CPU.
565 See also arch/mips/include/asm/mipsregs.h.
567 CONF_CM_CACHABLE_NO_WA
570 CONF_CM_CACHABLE_NONCOHERENT
574 CONF_CM_CACHABLE_ACCELERATED
576 CONFIG_SYS_XWAY_EBU_BOOTCFG
578 Special option for Lantiq XWAY SoCs for booting from NOR flash.
579 See also arch/mips/cpu/mips32/start.S.
581 CONFIG_XWAY_SWAP_BYTES
583 Enable compilation of tools/xway-swap-bytes needed for Lantiq
584 XWAY SoCs for booting from NOR flash. The U-Boot image needs to
585 be swapped if a flash programmer is used.
588 CONFIG_SYS_EXCEPTION_VECTORS_HIGH
590 Select high exception vectors of the ARM core, e.g., do not
591 clear the V bit of the c1 register of CP15.
594 Generic timer clock source frequency.
596 COUNTER_FREQUENCY_REAL
597 Generic timer clock source frequency if the real clock is
598 different from COUNTER_FREQUENCY, and can only be determined
602 CONFIG_TEGRA_SUPPORT_NON_SECURE
604 Support executing U-Boot in non-secure (NS) mode. Certain
605 impossible actions will be skipped if the CPU is in NS mode,
606 such as ARM architectural timer initialization.
608 - Linux Kernel Interface:
611 U-Boot stores all clock information in Hz
612 internally. For binary compatibility with older Linux
613 kernels (which expect the clocks passed in the
614 bd_info data to be in MHz) the environment variable
615 "clocks_in_mhz" can be defined so that U-Boot
616 converts clock data to MHZ before passing it to the
618 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
619 "clocks_in_mhz=1" is automatically included in the
622 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
624 When transferring memsize parameter to Linux, some versions
625 expect it to be in bytes, others in MB.
626 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
630 New kernel versions are expecting firmware settings to be
631 passed using flattened device trees (based on open firmware
635 * New libfdt-based support
636 * Adds the "fdt" command
637 * The bootm command automatically updates the fdt
639 OF_CPU - The proper name of the cpus node (only required for
640 MPC512X and MPC5xxx based boards).
641 OF_SOC - The proper name of the soc node (only required for
642 MPC512X and MPC5xxx based boards).
643 OF_TBCLK - The timebase frequency.
644 OF_STDOUT_PATH - The path to the console device
646 boards with QUICC Engines require OF_QE to set UCC MAC
649 CONFIG_OF_BOARD_SETUP
651 Board code has addition modification that it wants to make
652 to the flat device tree before handing it off to the kernel
654 CONFIG_OF_SYSTEM_SETUP
656 Other code has addition modification that it wants to make
657 to the flat device tree before handing it off to the kernel.
658 This causes ft_system_setup() to be called before booting
663 U-Boot can detect if an IDE device is present or not.
664 If not, and this new config option is activated, U-Boot
665 removes the ATA node from the DTS before booting Linux,
666 so the Linux IDE driver does not probe the device and
667 crash. This is needed for buggy hardware (uc101) where
668 no pull down resistor is connected to the signal IDE5V_DD7.
670 CONFIG_MACH_TYPE [relevant for ARM only][mandatory]
672 This setting is mandatory for all boards that have only one
673 machine type and must be used to specify the machine type
674 number as it appears in the ARM machine registry
675 (see http://www.arm.linux.org.uk/developer/machines/).
676 Only boards that have multiple machine types supported
677 in a single configuration file and the machine type is
678 runtime discoverable, do not have to use this setting.
680 - vxWorks boot parameters:
682 bootvx constructs a valid bootline using the following
683 environments variables: bootdev, bootfile, ipaddr, netmask,
684 serverip, gatewayip, hostname, othbootargs.
685 It loads the vxWorks image pointed bootfile.
687 Note: If a "bootargs" environment is defined, it will overwride
688 the defaults discussed just above.
690 - Cache Configuration:
691 CONFIG_SYS_ICACHE_OFF - Do not enable instruction cache in U-Boot
692 CONFIG_SYS_DCACHE_OFF - Do not enable data cache in U-Boot
693 CONFIG_SYS_L2CACHE_OFF- Do not enable L2 cache in U-Boot
695 - Cache Configuration for ARM:
696 CONFIG_SYS_L2_PL310 - Enable support for ARM PL310 L2 cache
698 CONFIG_SYS_PL310_BASE - Physical base address of PL310
699 controller register space
704 Define this if you want support for Amba PrimeCell PL010 UARTs.
708 Define this if you want support for Amba PrimeCell PL011 UARTs.
712 If you have Amba PrimeCell PL011 UARTs, set this variable to
713 the clock speed of the UARTs.
717 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
718 define this to a list of base addresses for each (supported)
719 port. See e.g. include/configs/versatile.h
721 CONFIG_SERIAL_HW_FLOW_CONTROL
723 Define this variable to enable hw flow control in serial driver.
724 Current user of this option is drivers/serial/nsl16550.c driver
727 Depending on board, define exactly one serial port
728 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
729 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
730 console by defining CONFIG_8xx_CONS_NONE
732 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
733 port routines must be defined elsewhere
734 (i.e. serial_init(), serial_getc(), ...)
737 CONFIG_BAUDRATE - in bps
738 Select one of the baudrates listed in
739 CONFIG_SYS_BAUDRATE_TABLE, see below.
740 CONFIG_SYS_BRGCLK_PRESCALE, baudrate prescale
742 - Console Rx buffer length
743 With CONFIG_SYS_SMC_RXBUFLEN it is possible to define
744 the maximum receive buffer length for the SMC.
745 This option is actual only for 82xx and 8xx possible.
746 If using CONFIG_SYS_SMC_RXBUFLEN also CONFIG_SYS_MAXIDLE
747 must be defined, to setup the maximum idle timeout for
752 Only needed when CONFIG_BOOTDELAY is enabled;
753 define a command string that is automatically executed
754 when no character is read on the console interface
755 within "Boot Delay" after reset.
758 This can be used to pass arguments to the bootm
759 command. The value of CONFIG_BOOTARGS goes into the
760 environment value "bootargs".
762 CONFIG_RAMBOOT and CONFIG_NFSBOOT
763 The value of these goes into the environment as
764 "ramboot" and "nfsboot" respectively, and can be used
765 as a convenience, when switching between booting from
769 CONFIG_BOOTCOUNT_LIMIT
770 Implements a mechanism for detecting a repeating reboot
772 http://www.denx.de/wiki/view/DULG/UBootBootCountLimit
775 If no softreset save registers are found on the hardware
776 "bootcount" is stored in the environment. To prevent a
777 saveenv on all reboots, the environment variable
778 "upgrade_available" is used. If "upgrade_available" is
779 0, "bootcount" is always 0, if "upgrade_available" is
780 1 "bootcount" is incremented in the environment.
781 So the Userspace Applikation must set the "upgrade_available"
782 and "bootcount" variable to 0, if a boot was successfully.
787 When this option is #defined, the existence of the
788 environment variable "preboot" will be checked
789 immediately before starting the CONFIG_BOOTDELAY
790 countdown and/or running the auto-boot command resp.
791 entering interactive mode.
793 This feature is especially useful when "preboot" is
794 automatically generated or modified. For an example
795 see the LWMON board specific code: here "preboot" is
796 modified when the user holds down a certain
797 combination of keys on the (special) keyboard when
800 - Serial Download Echo Mode:
802 If defined to 1, all characters received during a
803 serial download (using the "loads" command) are
804 echoed back. This might be needed by some terminal
805 emulations (like "cu"), but may as well just take
806 time on others. This setting #define's the initial
807 value of the "loads_echo" environment variable.
809 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
811 Select one of the baudrates listed in
812 CONFIG_SYS_BAUDRATE_TABLE, see below.
815 Monitor commands can be included or excluded
816 from the build by using the #include files
817 <config_cmd_all.h> and #undef'ing unwanted
818 commands, or adding #define's for wanted commands.
820 The default command configuration includes all commands
821 except those marked below with a "*".
823 CONFIG_CMD_AES AES 128 CBC encrypt/decrypt
824 CONFIG_CMD_ASKENV * ask for env variable
825 CONFIG_CMD_BDI bdinfo
826 CONFIG_CMD_BOOTD bootd
827 CONFIG_CMD_BOOTI * ARM64 Linux kernel Image support
828 CONFIG_CMD_CACHE * icache, dcache
829 CONFIG_CMD_CONSOLE coninfo
830 CONFIG_CMD_CRC32 * crc32
831 CONFIG_CMD_DHCP * DHCP support
832 CONFIG_CMD_DIAG * Diagnostics
833 CONFIG_CMD_ECHO echo arguments
834 CONFIG_CMD_EDITENV edit env variable
835 CONFIG_CMD_ELF * bootelf, bootvx
836 CONFIG_CMD_ENV_EXISTS * check existence of env variable
837 CONFIG_CMD_EXPORTENV * export the environment
838 CONFIG_CMD_EXT2 * ext2 command support
839 CONFIG_CMD_EXT4 * ext4 command support
840 CONFIG_CMD_FS_GENERIC * filesystem commands (e.g. load, ls)
841 that work for multiple fs types
842 CONFIG_CMD_FS_UUID * Look up a filesystem UUID
843 CONFIG_CMD_SAVEENV saveenv
844 CONFIG_CMD_FAT * FAT command support
845 CONFIG_CMD_FLASH flinfo, erase, protect
846 CONFIG_CMD_FPGA FPGA device initialization support
847 CONFIG_CMD_GO * the 'go' command (exec code)
848 CONFIG_CMD_GREPENV * search environment
849 CONFIG_CMD_I2C * I2C serial bus support
850 CONFIG_CMD_IDE * IDE harddisk support
851 CONFIG_CMD_IMI iminfo
852 CONFIG_CMD_IMLS List all images found in NOR flash
853 CONFIG_CMD_IMLS_NAND * List all images found in NAND flash
854 CONFIG_CMD_IMMAP * IMMR dump support
855 CONFIG_CMD_IOTRACE * I/O tracing for debugging
856 CONFIG_CMD_IMPORTENV * import an environment
857 CONFIG_CMD_INI * import data from an ini file into the env
858 CONFIG_CMD_IRQ * irqinfo
859 CONFIG_CMD_ITEST Integer/string test of 2 values
860 CONFIG_CMD_JFFS2 * JFFS2 Support
861 CONFIG_CMD_KGDB * kgdb
862 CONFIG_CMD_LDRINFO * ldrinfo (display Blackfin loader)
863 CONFIG_CMD_LINK_LOCAL * link-local IP address auto-configuration
865 CONFIG_CMD_LOADB loadb
866 CONFIG_CMD_LOADS loads
867 CONFIG_CMD_MD5SUM * print md5 message digest
868 (requires CONFIG_CMD_MEMORY and CONFIG_MD5)
869 CONFIG_CMD_MEMINFO * Display detailed memory information
870 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
872 CONFIG_CMD_MEMTEST * mtest
873 CONFIG_CMD_MISC Misc functions like sleep etc
874 CONFIG_CMD_MMC * MMC memory mapped support
875 CONFIG_CMD_MII * MII utility commands
876 CONFIG_CMD_MTDPARTS * MTD partition support
877 CONFIG_CMD_NAND * NAND support
878 CONFIG_CMD_NET bootp, tftpboot, rarpboot
879 CONFIG_CMD_NFS NFS support
880 CONFIG_CMD_PCA953X * PCA953x I2C gpio commands
881 CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command
882 CONFIG_CMD_PCI * pciinfo
883 CONFIG_CMD_PCMCIA * PCMCIA support
884 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
886 CONFIG_CMD_PORTIO * Port I/O
887 CONFIG_CMD_READ * Read raw data from partition
888 CONFIG_CMD_REGINFO * Register dump
889 CONFIG_CMD_RUN run command in env variable
890 CONFIG_CMD_SANDBOX * sb command to access sandbox features
891 CONFIG_CMD_SAVES * save S record dump
892 CONFIG_SCSI * SCSI Support
893 CONFIG_CMD_SDRAM * print SDRAM configuration information
894 (requires CONFIG_CMD_I2C)
895 CONFIG_CMD_SETGETDCR Support for DCR Register access
897 CONFIG_CMD_SF * Read/write/erase SPI NOR flash
898 CONFIG_CMD_SHA1SUM * print sha1 memory digest
899 (requires CONFIG_CMD_MEMORY)
900 CONFIG_CMD_SOFTSWITCH * Soft switch setting command for BF60x
901 CONFIG_CMD_SOURCE "source" command Support
902 CONFIG_CMD_SPI * SPI serial bus support
903 CONFIG_CMD_TFTPSRV * TFTP transfer in server mode
904 CONFIG_CMD_TFTPPUT * TFTP put command (upload)
905 CONFIG_CMD_TIME * run command and report execution time (ARM specific)
906 CONFIG_CMD_TIMER * access to the system tick timer
907 CONFIG_CMD_USB * USB support
908 CONFIG_CMD_CDP * Cisco Discover Protocol support
909 CONFIG_CMD_MFSL * Microblaze FSL support
910 CONFIG_CMD_XIMG Load part of Multi Image
911 CONFIG_CMD_UUID * Generate random UUID or GUID string
913 EXAMPLE: If you want all functions except of network
914 support you can write:
916 #include "config_cmd_all.h"
917 #undef CONFIG_CMD_NET
920 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
922 Note: Don't enable the "icache" and "dcache" commands
923 (configuration option CONFIG_CMD_CACHE) unless you know
924 what you (and your U-Boot users) are doing. Data
925 cache cannot be enabled on systems like the 8xx or
926 8260 (where accesses to the IMMR region must be
927 uncached), and it cannot be disabled on all other
928 systems where we (mis-) use the data cache to hold an
929 initial stack and some data.
932 XXX - this list needs to get updated!
934 - Removal of commands
935 If no commands are needed to boot, you can disable
936 CONFIG_CMDLINE to remove them. In this case, the command line
937 will not be available, and when U-Boot wants to execute the
938 boot command (on start-up) it will call board_run_command()
939 instead. This can reduce image size significantly for very
940 simple boot procedures.
942 - Regular expression support:
944 If this variable is defined, U-Boot is linked against
945 the SLRE (Super Light Regular Expression) library,
946 which adds regex support to some commands, as for
947 example "env grep" and "setexpr".
951 If this variable is defined, U-Boot will use a device tree
952 to configure its devices, instead of relying on statically
953 compiled #defines in the board file. This option is
954 experimental and only available on a few boards. The device
955 tree is available in the global data as gd->fdt_blob.
957 U-Boot needs to get its device tree from somewhere. This can
958 be done using one of the three options below:
961 If this variable is defined, U-Boot will embed a device tree
962 binary in its image. This device tree file should be in the
963 board directory and called <soc>-<board>.dts. The binary file
964 is then picked up in board_init_f() and made available through
965 the global data structure as gd->blob.
968 If this variable is defined, U-Boot will build a device tree
969 binary. It will be called u-boot.dtb. Architecture-specific
970 code will locate it at run-time. Generally this works by:
972 cat u-boot.bin u-boot.dtb >image.bin
974 and in fact, U-Boot does this for you, creating a file called
975 u-boot-dtb.bin which is useful in the common case. You can
976 still use the individual files if you need something more
980 If this variable is defined, U-Boot will use the device tree
981 provided by the board at runtime instead of embedding one with
982 the image. Only boards defining board_fdt_blob_setup() support
983 this option (see include/fdtdec.h file).
987 If this variable is defined, it enables watchdog
988 support for the SoC. There must be support in the SoC
989 specific code for a watchdog. For the 8xx and 8260
990 CPUs, the SIU Watchdog feature is enabled in the SYPCR
991 register. When supported for a specific SoC is
992 available, then no further board specific code should
996 When using a watchdog circuitry external to the used
997 SoC, then define this variable and provide board
998 specific code for the "hw_watchdog_reset" function.
1000 CONFIG_AT91_HW_WDT_TIMEOUT
1001 specify the timeout in seconds. default 2 seconds.
1004 CONFIG_VERSION_VARIABLE
1005 If this variable is defined, an environment variable
1006 named "ver" is created by U-Boot showing the U-Boot
1007 version as printed by the "version" command.
1008 Any change to this variable will be reverted at the
1013 When CONFIG_CMD_DATE is selected, the type of the RTC
1014 has to be selected, too. Define exactly one of the
1017 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
1018 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
1019 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC
1020 CONFIG_RTC_MC146818 - use MC146818 RTC
1021 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
1022 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
1023 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
1024 CONFIG_RTC_DS1339 - use Maxim, Inc. DS1339 RTC
1025 CONFIG_RTC_DS164x - use Dallas DS164x RTC
1026 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
1027 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
1028 CONFIG_SYS_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
1029 CONFIG_SYS_RV3029_TCR - enable trickle charger on
1032 Note that if the RTC uses I2C, then the I2C interface
1033 must also be configured. See I2C Support, below.
1036 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
1038 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
1039 chip-ngpio pairs that tell the PCA953X driver the number of
1040 pins supported by a particular chip.
1042 Note that if the GPIO device uses I2C, then the I2C interface
1043 must also be configured. See I2C Support, below.
1046 When CONFIG_IO_TRACE is selected, U-Boot intercepts all I/O
1047 accesses and can checksum them or write a list of them out
1048 to memory. See the 'iotrace' command for details. This is
1049 useful for testing device drivers since it can confirm that
1050 the driver behaves the same way before and after a code
1051 change. Currently this is supported on sandbox and arm. To
1052 add support for your architecture, add '#include <iotrace.h>'
1053 to the bottom of arch/<arch>/include/asm/io.h and test.
1055 Example output from the 'iotrace stats' command is below.
1056 Note that if the trace buffer is exhausted, the checksum will
1057 still continue to operate.
1060 Start: 10000000 (buffer start address)
1061 Size: 00010000 (buffer size)
1062 Offset: 00000120 (current buffer offset)
1063 Output: 10000120 (start + offset)
1064 Count: 00000018 (number of trace records)
1065 CRC32: 9526fb66 (CRC32 of all trace records)
1067 - Timestamp Support:
1069 When CONFIG_TIMESTAMP is selected, the timestamp
1070 (date and time) of an image is printed by image
1071 commands like bootm or iminfo. This option is
1072 automatically enabled when you select CONFIG_CMD_DATE .
1074 - Partition Labels (disklabels) Supported:
1075 Zero or more of the following:
1076 CONFIG_MAC_PARTITION Apple's MacOS partition table.
1077 CONFIG_DOS_PARTITION MS Dos partition table, traditional on the
1078 Intel architecture, USB sticks, etc.
1079 CONFIG_ISO_PARTITION ISO partition table, used on CDROM etc.
1080 CONFIG_EFI_PARTITION GPT partition table, common when EFI is the
1081 bootloader. Note 2TB partition limit; see
1083 CONFIG_MTD_PARTITIONS Memory Technology Device partition table.
1085 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
1086 CONFIG_SCSI) you must configure support for at
1087 least one non-MTD partition type as well.
1090 CONFIG_IDE_RESET_ROUTINE - this is defined in several
1091 board configurations files but used nowhere!
1093 CONFIG_IDE_RESET - is this is defined, IDE Reset will
1094 be performed by calling the function
1095 ide_set_reset(int reset)
1096 which has to be defined in a board specific file
1101 Set this to enable ATAPI support.
1106 Set this to enable support for disks larger than 137GB
1107 Also look at CONFIG_SYS_64BIT_LBA.
1108 Whithout these , LBA48 support uses 32bit variables and will 'only'
1109 support disks up to 2.1TB.
1111 CONFIG_SYS_64BIT_LBA:
1112 When enabled, makes the IDE subsystem use 64bit sector addresses.
1116 At the moment only there is only support for the
1117 SYM53C8XX SCSI controller; define
1118 CONFIG_SCSI_SYM53C8XX to enable it.
1120 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
1121 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
1122 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
1123 maximum numbers of LUNs, SCSI ID's and target
1125 CONFIG_SYS_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
1127 The environment variable 'scsidevs' is set to the number of
1128 SCSI devices found during the last scan.
1130 - NETWORK Support (PCI):
1132 Support for Intel 8254x/8257x gigabit chips.
1135 Utility code for direct access to the SPI bus on Intel 8257x.
1136 This does not do anything useful unless you set at least one
1137 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
1139 CONFIG_E1000_SPI_GENERIC
1140 Allow generic access to the SPI bus on the Intel 8257x, for
1141 example with the "sspi" command.
1144 Management command for E1000 devices. When used on devices
1145 with SPI support you can reprogram the EEPROM from U-Boot.
1148 Support for Intel 82557/82559/82559ER chips.
1149 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
1150 write routine for first time initialisation.
1153 Support for Digital 2114x chips.
1154 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
1155 modem chip initialisation (KS8761/QS6611).
1158 Support for National dp83815 chips.
1161 Support for National dp8382[01] gigabit chips.
1163 - NETWORK Support (other):
1165 CONFIG_DRIVER_AT91EMAC
1166 Support for AT91RM9200 EMAC.
1169 Define this to use reduced MII inteface
1171 CONFIG_DRIVER_AT91EMAC_QUIET
1172 If this defined, the driver is quiet.
1173 The driver doen't show link status messages.
1175 CONFIG_CALXEDA_XGMAC
1176 Support for the Calxeda XGMAC device
1179 Support for SMSC's LAN91C96 chips.
1181 CONFIG_LAN91C96_USE_32_BIT
1182 Define this to enable 32 bit addressing
1185 Support for SMSC's LAN91C111 chip
1187 CONFIG_SMC91111_BASE
1188 Define this to hold the physical address
1189 of the device (I/O space)
1191 CONFIG_SMC_USE_32_BIT
1192 Define this if data bus is 32 bits
1194 CONFIG_SMC_USE_IOFUNCS
1195 Define this to use i/o functions instead of macros
1196 (some hardware wont work with macros)
1198 CONFIG_DRIVER_TI_EMAC
1199 Support for davinci emac
1201 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
1202 Define this if you have more then 3 PHYs.
1205 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
1207 CONFIG_FTGMAC100_EGIGA
1208 Define this to use GE link update with gigabit PHY.
1209 Define this if FTGMAC100 is connected to gigabit PHY.
1210 If your system has 10/100 PHY only, it might not occur
1211 wrong behavior. Because PHY usually return timeout or
1212 useless data when polling gigabit status and gigabit
1213 control registers. This behavior won't affect the
1214 correctnessof 10/100 link speed update.
1217 Support for SMSC's LAN911x and LAN921x chips
1220 Define this to hold the physical address
1221 of the device (I/O space)
1223 CONFIG_SMC911X_32_BIT
1224 Define this if data bus is 32 bits
1226 CONFIG_SMC911X_16_BIT
1227 Define this if data bus is 16 bits. If your processor
1228 automatically converts one 32 bit word to two 16 bit
1229 words you may also try CONFIG_SMC911X_32_BIT.
1232 Support for Renesas on-chip Ethernet controller
1234 CONFIG_SH_ETHER_USE_PORT
1235 Define the number of ports to be used
1237 CONFIG_SH_ETHER_PHY_ADDR
1238 Define the ETH PHY's address
1240 CONFIG_SH_ETHER_CACHE_WRITEBACK
1241 If this option is set, the driver enables cache flush.
1245 Support for PWM module on the imx6.
1249 Support TPM devices.
1251 CONFIG_TPM_TIS_INFINEON
1252 Support for Infineon i2c bus TPM devices. Only one device
1253 per system is supported at this time.
1255 CONFIG_TPM_TIS_I2C_BURST_LIMITATION
1256 Define the burst count bytes upper limit
1259 Support for STMicroelectronics TPM devices. Requires DM_TPM support.
1261 CONFIG_TPM_ST33ZP24_I2C
1262 Support for STMicroelectronics ST33ZP24 I2C devices.
1263 Requires TPM_ST33ZP24 and I2C.
1265 CONFIG_TPM_ST33ZP24_SPI
1266 Support for STMicroelectronics ST33ZP24 SPI devices.
1267 Requires TPM_ST33ZP24 and SPI.
1269 CONFIG_TPM_ATMEL_TWI
1270 Support for Atmel TWI TPM device. Requires I2C support.
1273 Support for generic parallel port TPM devices. Only one device
1274 per system is supported at this time.
1276 CONFIG_TPM_TIS_BASE_ADDRESS
1277 Base address where the generic TPM device is mapped
1278 to. Contemporary x86 systems usually map it at
1282 Add tpm monitor functions.
1283 Requires CONFIG_TPM. If CONFIG_TPM_AUTH_SESSIONS is set, also
1284 provides monitor access to authorized functions.
1287 Define this to enable the TPM support library which provides
1288 functional interfaces to some TPM commands.
1289 Requires support for a TPM device.
1291 CONFIG_TPM_AUTH_SESSIONS
1292 Define this to enable authorized functions in the TPM library.
1293 Requires CONFIG_TPM and CONFIG_SHA1.
1296 At the moment only the UHCI host controller is
1297 supported (PIP405, MIP405, MPC5200); define
1298 CONFIG_USB_UHCI to enable it.
1299 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
1300 and define CONFIG_USB_STORAGE to enable the USB
1303 Supported are USB Keyboards and USB Floppy drives
1305 MPC5200 USB requires additional defines:
1307 for 528 MHz Clock: 0x0001bbbb
1311 for differential drivers: 0x00001000
1312 for single ended drivers: 0x00005000
1313 for differential drivers on PSC3: 0x00000100
1314 for single ended drivers on PSC3: 0x00004100
1315 CONFIG_SYS_USB_EVENT_POLL
1316 May be defined to allow interrupt polling
1317 instead of using asynchronous interrupts
1319 CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
1320 txfilltuning field in the EHCI controller on reset.
1322 CONFIG_USB_DWC2_REG_ADDR the physical CPU address of the DWC2
1323 HW module registers.
1326 Define the below if you wish to use the USB console.
1327 Once firmware is rebuilt from a serial console issue the
1328 command "setenv stdin usbtty; setenv stdout usbtty" and
1329 attach your USB cable. The Unix command "dmesg" should print
1330 it has found a new device. The environment variable usbtty
1331 can be set to gserial or cdc_acm to enable your device to
1332 appear to a USB host as a Linux gserial device or a
1333 Common Device Class Abstract Control Model serial device.
1334 If you select usbtty = gserial you should be able to enumerate
1336 # modprobe usbserial vendor=0xVendorID product=0xProductID
1337 else if using cdc_acm, simply setting the environment
1338 variable usbtty to be cdc_acm should suffice. The following
1339 might be defined in YourBoardName.h
1342 Define this to build a UDC device
1345 Define this to have a tty type of device available to
1346 talk to the UDC device
1349 Define this to enable the high speed support for usb
1350 device and usbtty. If this feature is enabled, a routine
1351 int is_usbd_high_speed(void)
1352 also needs to be defined by the driver to dynamically poll
1353 whether the enumeration has succeded at high speed or full
1356 CONFIG_SYS_CONSOLE_IS_IN_ENV
1357 Define this if you want stdin, stdout &/or stderr to
1361 CONFIG_SYS_USB_EXTC_CLK 0xBLAH
1362 Derive USB clock from external clock "blah"
1363 - CONFIG_SYS_USB_EXTC_CLK 0x02
1365 If you have a USB-IF assigned VendorID then you may wish to
1366 define your own vendor specific values either in BoardName.h
1367 or directly in usbd_vendor_info.h. If you don't define
1368 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
1369 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
1370 should pretend to be a Linux device to it's target host.
1372 CONFIG_USBD_MANUFACTURER
1373 Define this string as the name of your company for
1374 - CONFIG_USBD_MANUFACTURER "my company"
1376 CONFIG_USBD_PRODUCT_NAME
1377 Define this string as the name of your product
1378 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
1380 CONFIG_USBD_VENDORID
1381 Define this as your assigned Vendor ID from the USB
1382 Implementors Forum. This *must* be a genuine Vendor ID
1383 to avoid polluting the USB namespace.
1384 - CONFIG_USBD_VENDORID 0xFFFF
1386 CONFIG_USBD_PRODUCTID
1387 Define this as the unique Product ID
1389 - CONFIG_USBD_PRODUCTID 0xFFFF
1391 - ULPI Layer Support:
1392 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
1393 the generic ULPI layer. The generic layer accesses the ULPI PHY
1394 via the platform viewport, so you need both the genric layer and
1395 the viewport enabled. Currently only Chipidea/ARC based
1396 viewport is supported.
1397 To enable the ULPI layer support, define CONFIG_USB_ULPI and
1398 CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
1399 If your ULPI phy needs a different reference clock than the
1400 standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to
1401 the appropriate value in Hz.
1404 The MMC controller on the Intel PXA is supported. To
1405 enable this define CONFIG_MMC. The MMC can be
1406 accessed from the boot prompt by mapping the device
1407 to physical memory similar to flash. Command line is
1408 enabled with CONFIG_CMD_MMC. The MMC driver also works with
1409 the FAT fs. This is enabled with CONFIG_CMD_FAT.
1412 Support for Renesas on-chip MMCIF controller
1414 CONFIG_SH_MMCIF_ADDR
1415 Define the base address of MMCIF registers
1418 Define the clock frequency for MMCIF
1420 CONFIG_SUPPORT_EMMC_BOOT
1421 Enable some additional features of the eMMC boot partitions.
1423 CONFIG_SUPPORT_EMMC_RPMB
1424 Enable the commands for reading, writing and programming the
1425 key for the Replay Protection Memory Block partition in eMMC.
1427 - USB Device Firmware Update (DFU) class support:
1428 CONFIG_USB_FUNCTION_DFU
1429 This enables the USB portion of the DFU USB class
1432 This enables the command "dfu" which is used to have
1433 U-Boot create a DFU class device via USB. This command
1434 requires that the "dfu_alt_info" environment variable be
1435 set and define the alt settings to expose to the host.
1438 This enables support for exposing (e)MMC devices via DFU.
1441 This enables support for exposing NAND devices via DFU.
1444 This enables support for exposing RAM via DFU.
1445 Note: DFU spec refer to non-volatile memory usage, but
1446 allow usages beyond the scope of spec - here RAM usage,
1447 one that would help mostly the developer.
1449 CONFIG_SYS_DFU_DATA_BUF_SIZE
1450 Dfu transfer uses a buffer before writing data to the
1451 raw storage device. Make the size (in bytes) of this buffer
1452 configurable. The size of this buffer is also configurable
1453 through the "dfu_bufsiz" environment variable.
1455 CONFIG_SYS_DFU_MAX_FILE_SIZE
1456 When updating files rather than the raw storage device,
1457 we use a static buffer to copy the file into and then write
1458 the buffer once we've been given the whole file. Define
1459 this to the maximum filesize (in bytes) for the buffer.
1460 Default is 4 MiB if undefined.
1462 DFU_DEFAULT_POLL_TIMEOUT
1463 Poll timeout [ms], is the timeout a device can send to the
1464 host. The host must wait for this timeout before sending
1465 a subsequent DFU_GET_STATUS request to the device.
1467 DFU_MANIFEST_POLL_TIMEOUT
1468 Poll timeout [ms], which the device sends to the host when
1469 entering dfuMANIFEST state. Host waits this timeout, before
1470 sending again an USB request to the device.
1472 - USB Device Android Fastboot support:
1473 CONFIG_USB_FUNCTION_FASTBOOT
1474 This enables the USB part of the fastboot gadget
1477 This enables the command "fastboot" which enables the Android
1478 fastboot mode for the platform's USB device. Fastboot is a USB
1479 protocol for downloading images, flashing and device control
1480 used on Android devices.
1481 See doc/README.android-fastboot for more information.
1483 CONFIG_ANDROID_BOOT_IMAGE
1484 This enables support for booting images which use the Android
1485 image format header.
1487 CONFIG_FASTBOOT_BUF_ADDR
1488 The fastboot protocol requires a large memory buffer for
1489 downloads. Define this to the starting RAM address to use for
1492 CONFIG_FASTBOOT_BUF_SIZE
1493 The fastboot protocol requires a large memory buffer for
1494 downloads. This buffer should be as large as possible for a
1495 platform. Define this to the size available RAM for fastboot.
1497 CONFIG_FASTBOOT_FLASH
1498 The fastboot protocol includes a "flash" command for writing
1499 the downloaded image to a non-volatile storage device. Define
1500 this to enable the "fastboot flash" command.
1502 CONFIG_FASTBOOT_FLASH_MMC_DEV
1503 The fastboot "flash" command requires additional information
1504 regarding the non-volatile storage device. Define this to
1505 the eMMC device that fastboot should use to store the image.
1507 CONFIG_FASTBOOT_GPT_NAME
1508 The fastboot "flash" command supports writing the downloaded
1509 image to the Protective MBR and the Primary GUID Partition
1510 Table. (Additionally, this downloaded image is post-processed
1511 to generate and write the Backup GUID Partition Table.)
1512 This occurs when the specified "partition name" on the
1513 "fastboot flash" command line matches this value.
1514 The default is "gpt" if undefined.
1516 CONFIG_FASTBOOT_MBR_NAME
1517 The fastboot "flash" command supports writing the downloaded
1519 This occurs when the "partition name" specified on the
1520 "fastboot flash" command line matches this value.
1521 If not defined the default value "mbr" is used.
1523 - Journaling Flash filesystem support:
1525 Define these for a default partition on a NAND device
1527 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1528 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1529 Define these for a default partition on a NOR device
1531 - FAT(File Allocation Table) filesystem write function support:
1534 Define this to enable support for saving memory data as a
1535 file in FAT formatted partition.
1537 This will also enable the command "fatwrite" enabling the
1538 user to write files to FAT.
1540 - FAT(File Allocation Table) filesystem cluster size:
1541 CONFIG_FS_FAT_MAX_CLUSTSIZE
1543 Define the max cluster size for fat operations else
1544 a default value of 65536 will be defined.
1547 See Kconfig help for available keyboard drivers.
1551 Define this to enable a custom keyboard support.
1552 This simply calls drv_keyboard_init() which must be
1553 defined in your board-specific files. This option is deprecated
1554 and is only used by novena. For new boards, use driver model
1559 Enable the Freescale DIU video driver. Reference boards for
1560 SOCs that have a DIU should define this macro to enable DIU
1561 support, and should also define these other macros:
1566 CONFIG_VIDEO_SW_CURSOR
1567 CONFIG_VGA_AS_SINGLE_DEVICE
1569 CONFIG_VIDEO_BMP_LOGO
1571 The DIU driver will look for the 'video-mode' environment
1572 variable, and if defined, enable the DIU as a console during
1573 boot. See the documentation file doc/README.video for a
1574 description of this variable.
1576 - LCD Support: CONFIG_LCD
1578 Define this to enable LCD support (for output to LCD
1579 display); also select one of the supported displays
1580 by defining one of these:
1584 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1586 CONFIG_NEC_NL6448AC33:
1588 NEC NL6448AC33-18. Active, color, single scan.
1590 CONFIG_NEC_NL6448BC20
1592 NEC NL6448BC20-08. 6.5", 640x480.
1593 Active, color, single scan.
1595 CONFIG_NEC_NL6448BC33_54
1597 NEC NL6448BC33-54. 10.4", 640x480.
1598 Active, color, single scan.
1602 Sharp 320x240. Active, color, single scan.
1603 It isn't 16x9, and I am not sure what it is.
1605 CONFIG_SHARP_LQ64D341
1607 Sharp LQ64D341 display, 640x480.
1608 Active, color, single scan.
1612 HLD1045 display, 640x480.
1613 Active, color, single scan.
1617 Optrex CBL50840-2 NF-FW 99 22 M5
1619 Hitachi LMG6912RPFC-00T
1623 320x240. Black & white.
1625 CONFIG_LCD_ALIGNMENT
1627 Normally the LCD is page-aligned (typically 4KB). If this is
1628 defined then the LCD will be aligned to this value instead.
1629 For ARM it is sometimes useful to use MMU_SECTION_SIZE
1630 here, since it is cheaper to change data cache settings on
1631 a per-section basis.
1636 Sometimes, for example if the display is mounted in portrait
1637 mode or even if it's mounted landscape but rotated by 180degree,
1638 we need to rotate our content of the display relative to the
1639 framebuffer, so that user can read the messages which are
1641 Once CONFIG_LCD_ROTATION is defined, the lcd_console will be
1642 initialized with a given rotation from "vl_rot" out of
1643 "vidinfo_t" which is provided by the board specific code.
1644 The value for vl_rot is coded as following (matching to
1645 fbcon=rotate:<n> linux-kernel commandline):
1646 0 = no rotation respectively 0 degree
1647 1 = 90 degree rotation
1648 2 = 180 degree rotation
1649 3 = 270 degree rotation
1651 If CONFIG_LCD_ROTATION is not defined, the console will be
1652 initialized with 0degree rotation.
1656 Support drawing of RLE8-compressed bitmaps on the LCD.
1660 Enables an 'i2c edid' command which can read EDID
1661 information over I2C from an attached LCD display.
1663 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1665 If this option is set, the environment is checked for
1666 a variable "splashimage". If found, the usual display
1667 of logo, copyright and system information on the LCD
1668 is suppressed and the BMP image at the address
1669 specified in "splashimage" is loaded instead. The
1670 console is redirected to the "nulldev", too. This
1671 allows for a "silent" boot where a splash screen is
1672 loaded very quickly after power-on.
1674 CONFIG_SPLASHIMAGE_GUARD
1676 If this option is set, then U-Boot will prevent the environment
1677 variable "splashimage" from being set to a problematic address
1678 (see doc/README.displaying-bmps).
1679 This option is useful for targets where, due to alignment
1680 restrictions, an improperly aligned BMP image will cause a data
1681 abort. If you think you will not have problems with unaligned
1682 accesses (for example because your toolchain prevents them)
1683 there is no need to set this option.
1685 CONFIG_SPLASH_SCREEN_ALIGN
1687 If this option is set the splash image can be freely positioned
1688 on the screen. Environment variable "splashpos" specifies the
1689 position as "x,y". If a positive number is given it is used as
1690 number of pixel from left/top. If a negative number is given it
1691 is used as number of pixel from right/bottom. You can also
1692 specify 'm' for centering the image.
1695 setenv splashpos m,m
1696 => image at center of screen
1698 setenv splashpos 30,20
1699 => image at x = 30 and y = 20
1701 setenv splashpos -10,m
1702 => vertically centered image
1703 at x = dspWidth - bmpWidth - 9
1705 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1707 If this option is set, additionally to standard BMP
1708 images, gzipped BMP images can be displayed via the
1709 splashscreen support or the bmp command.
1711 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1713 If this option is set, 8-bit RLE compressed BMP images
1714 can be displayed via the splashscreen support or the
1717 - Compression support:
1720 Enabled by default to support gzip compressed images.
1724 If this option is set, support for bzip2 compressed
1725 images is included. If not, only uncompressed and gzip
1726 compressed images are supported.
1728 NOTE: the bzip2 algorithm requires a lot of RAM, so
1729 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1734 If this option is set, support for lzma compressed
1737 Note: The LZMA algorithm adds between 2 and 4KB of code and it
1738 requires an amount of dynamic memory that is given by the
1741 (1846 + 768 << (lc + lp)) * sizeof(uint16)
1743 Where lc and lp stand for, respectively, Literal context bits
1744 and Literal pos bits.
1746 This value is upper-bounded by 14MB in the worst case. Anyway,
1747 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
1748 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
1749 a very small buffer.
1751 Use the lzmainfo tool to determinate the lc and lp values and
1752 then calculate the amount of needed dynamic memory (ensuring
1753 the appropriate CONFIG_SYS_MALLOC_LEN value).
1757 If this option is set, support for LZO compressed images
1763 The address of PHY on MII bus.
1765 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1767 The clock frequency of the MII bus
1771 If this option is set, support for speed/duplex
1772 detection of gigabit PHY is included.
1774 CONFIG_PHY_RESET_DELAY
1776 Some PHY like Intel LXT971A need extra delay after
1777 reset before any MII register access is possible.
1778 For such PHY, set this option to the usec delay
1779 required. (minimum 300usec for LXT971A)
1781 CONFIG_PHY_CMD_DELAY (ppc4xx)
1783 Some PHY like Intel LXT971A need extra delay after
1784 command issued before MII status register can be read
1789 Define a default value for the IP address to use for
1790 the default Ethernet interface, in case this is not
1791 determined through e.g. bootp.
1792 (Environment variable "ipaddr")
1794 - Server IP address:
1797 Defines a default value for the IP address of a TFTP
1798 server to contact when using the "tftboot" command.
1799 (Environment variable "serverip")
1801 CONFIG_KEEP_SERVERADDR
1803 Keeps the server's MAC address, in the env 'serveraddr'
1804 for passing to bootargs (like Linux's netconsole option)
1806 - Gateway IP address:
1809 Defines a default value for the IP address of the
1810 default router where packets to other networks are
1812 (Environment variable "gatewayip")
1817 Defines a default value for the subnet mask (or
1818 routing prefix) which is used to determine if an IP
1819 address belongs to the local subnet or needs to be
1820 forwarded through a router.
1821 (Environment variable "netmask")
1823 - Multicast TFTP Mode:
1826 Defines whether you want to support multicast TFTP as per
1827 rfc-2090; for example to work with atftp. Lets lots of targets
1828 tftp down the same boot image concurrently. Note: the Ethernet
1829 driver in use must provide a function: mcast() to join/leave a
1832 - BOOTP Recovery Mode:
1833 CONFIG_BOOTP_RANDOM_DELAY
1835 If you have many targets in a network that try to
1836 boot using BOOTP, you may want to avoid that all
1837 systems send out BOOTP requests at precisely the same
1838 moment (which would happen for instance at recovery
1839 from a power failure, when all systems will try to
1840 boot, thus flooding the BOOTP server. Defining
1841 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1842 inserted before sending out BOOTP requests. The
1843 following delays are inserted then:
1845 1st BOOTP request: delay 0 ... 1 sec
1846 2nd BOOTP request: delay 0 ... 2 sec
1847 3rd BOOTP request: delay 0 ... 4 sec
1849 BOOTP requests: delay 0 ... 8 sec
1851 CONFIG_BOOTP_ID_CACHE_SIZE
1853 BOOTP packets are uniquely identified using a 32-bit ID. The
1854 server will copy the ID from client requests to responses and
1855 U-Boot will use this to determine if it is the destination of
1856 an incoming response. Some servers will check that addresses
1857 aren't in use before handing them out (usually using an ARP
1858 ping) and therefore take up to a few hundred milliseconds to
1859 respond. Network congestion may also influence the time it
1860 takes for a response to make it back to the client. If that
1861 time is too long, U-Boot will retransmit requests. In order
1862 to allow earlier responses to still be accepted after these
1863 retransmissions, U-Boot's BOOTP client keeps a small cache of
1864 IDs. The CONFIG_BOOTP_ID_CACHE_SIZE controls the size of this
1865 cache. The default is to keep IDs for up to four outstanding
1866 requests. Increasing this will allow U-Boot to accept offers
1867 from a BOOTP client in networks with unusually high latency.
1869 - DHCP Advanced Options:
1870 You can fine tune the DHCP functionality by defining
1871 CONFIG_BOOTP_* symbols:
1873 CONFIG_BOOTP_SUBNETMASK
1874 CONFIG_BOOTP_GATEWAY
1875 CONFIG_BOOTP_HOSTNAME
1876 CONFIG_BOOTP_NISDOMAIN
1877 CONFIG_BOOTP_BOOTPATH
1878 CONFIG_BOOTP_BOOTFILESIZE
1881 CONFIG_BOOTP_SEND_HOSTNAME
1882 CONFIG_BOOTP_NTPSERVER
1883 CONFIG_BOOTP_TIMEOFFSET
1884 CONFIG_BOOTP_VENDOREX
1885 CONFIG_BOOTP_MAY_FAIL
1887 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1888 environment variable, not the BOOTP server.
1890 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
1891 after the configured retry count, the call will fail
1892 instead of starting over. This can be used to fail over
1893 to Link-local IP address configuration if the DHCP server
1896 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1897 serverip from a DHCP server, it is possible that more
1898 than one DNS serverip is offered to the client.
1899 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1900 serverip will be stored in the additional environment
1901 variable "dnsip2". The first DNS serverip is always
1902 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1905 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1906 to do a dynamic update of a DNS server. To do this, they
1907 need the hostname of the DHCP requester.
1908 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1909 of the "hostname" environment variable is passed as
1910 option 12 to the DHCP server.
1912 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1914 A 32bit value in microseconds for a delay between
1915 receiving a "DHCP Offer" and sending the "DHCP Request".
1916 This fixes a problem with certain DHCP servers that don't
1917 respond 100% of the time to a "DHCP request". E.g. On an
1918 AT91RM9200 processor running at 180MHz, this delay needed
1919 to be *at least* 15,000 usec before a Windows Server 2003
1920 DHCP server would reply 100% of the time. I recommend at
1921 least 50,000 usec to be safe. The alternative is to hope
1922 that one of the retries will be successful but note that
1923 the DHCP timeout and retry process takes a longer than
1926 - Link-local IP address negotiation:
1927 Negotiate with other link-local clients on the local network
1928 for an address that doesn't require explicit configuration.
1929 This is especially useful if a DHCP server cannot be guaranteed
1930 to exist in all environments that the device must operate.
1932 See doc/README.link-local for more information.
1935 CONFIG_CDP_DEVICE_ID
1937 The device id used in CDP trigger frames.
1939 CONFIG_CDP_DEVICE_ID_PREFIX
1941 A two character string which is prefixed to the MAC address
1946 A printf format string which contains the ascii name of
1947 the port. Normally is set to "eth%d" which sets
1948 eth0 for the first Ethernet, eth1 for the second etc.
1950 CONFIG_CDP_CAPABILITIES
1952 A 32bit integer which indicates the device capabilities;
1953 0x00000010 for a normal host which does not forwards.
1957 An ascii string containing the version of the software.
1961 An ascii string containing the name of the platform.
1965 A 32bit integer sent on the trigger.
1967 CONFIG_CDP_POWER_CONSUMPTION
1969 A 16bit integer containing the power consumption of the
1970 device in .1 of milliwatts.
1972 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1974 A byte containing the id of the VLAN.
1976 - Status LED: CONFIG_LED_STATUS
1978 Several configurations allow to display the current
1979 status using a LED. For instance, the LED will blink
1980 fast while running U-Boot code, stop blinking as
1981 soon as a reply to a BOOTP request was received, and
1982 start blinking slow once the Linux kernel is running
1983 (supported by a status LED driver in the Linux
1984 kernel). Defining CONFIG_LED_STATUS enables this
1989 CONFIG_LED_STATUS_GPIO
1990 The status LED can be connected to a GPIO pin.
1991 In such cases, the gpio_led driver can be used as a
1992 status LED backend implementation. Define CONFIG_LED_STATUS_GPIO
1993 to include the gpio_led driver in the U-Boot binary.
1995 CONFIG_GPIO_LED_INVERTED_TABLE
1996 Some GPIO connected LEDs may have inverted polarity in which
1997 case the GPIO high value corresponds to LED off state and
1998 GPIO low value corresponds to LED on state.
1999 In such cases CONFIG_GPIO_LED_INVERTED_TABLE may be defined
2000 with a list of GPIO LEDs that have inverted polarity.
2002 - CAN Support: CONFIG_CAN_DRIVER
2004 Defining CONFIG_CAN_DRIVER enables CAN driver support
2005 on those systems that support this (optional)
2006 feature, like the TQM8xxL modules.
2008 - I2C Support: CONFIG_SYS_I2C
2010 This enable the NEW i2c subsystem, and will allow you to use
2011 i2c commands at the u-boot command line (as long as you set
2012 CONFIG_CMD_I2C in CONFIG_COMMANDS) and communicate with i2c
2013 based realtime clock chips or other i2c devices. See
2014 common/cmd_i2c.c for a description of the command line
2017 ported i2c driver to the new framework:
2018 - drivers/i2c/soft_i2c.c:
2019 - activate first bus with CONFIG_SYS_I2C_SOFT define
2020 CONFIG_SYS_I2C_SOFT_SPEED and CONFIG_SYS_I2C_SOFT_SLAVE
2021 for defining speed and slave address
2022 - activate second bus with I2C_SOFT_DECLARATIONS2 define
2023 CONFIG_SYS_I2C_SOFT_SPEED_2 and CONFIG_SYS_I2C_SOFT_SLAVE_2
2024 for defining speed and slave address
2025 - activate third bus with I2C_SOFT_DECLARATIONS3 define
2026 CONFIG_SYS_I2C_SOFT_SPEED_3 and CONFIG_SYS_I2C_SOFT_SLAVE_3
2027 for defining speed and slave address
2028 - activate fourth bus with I2C_SOFT_DECLARATIONS4 define
2029 CONFIG_SYS_I2C_SOFT_SPEED_4 and CONFIG_SYS_I2C_SOFT_SLAVE_4
2030 for defining speed and slave address
2032 - drivers/i2c/fsl_i2c.c:
2033 - activate i2c driver with CONFIG_SYS_I2C_FSL
2034 define CONFIG_SYS_FSL_I2C_OFFSET for setting the register
2035 offset CONFIG_SYS_FSL_I2C_SPEED for the i2c speed and
2036 CONFIG_SYS_FSL_I2C_SLAVE for the slave addr of the first
2038 - If your board supports a second fsl i2c bus, define
2039 CONFIG_SYS_FSL_I2C2_OFFSET for the register offset
2040 CONFIG_SYS_FSL_I2C2_SPEED for the speed and
2041 CONFIG_SYS_FSL_I2C2_SLAVE for the slave address of the
2044 - drivers/i2c/tegra_i2c.c:
2045 - activate this driver with CONFIG_SYS_I2C_TEGRA
2046 - This driver adds 4 i2c buses with a fix speed from
2047 100000 and the slave addr 0!
2049 - drivers/i2c/ppc4xx_i2c.c
2050 - activate this driver with CONFIG_SYS_I2C_PPC4XX
2051 - CONFIG_SYS_I2C_PPC4XX_CH0 activate hardware channel 0
2052 - CONFIG_SYS_I2C_PPC4XX_CH1 activate hardware channel 1
2054 - drivers/i2c/i2c_mxc.c
2055 - activate this driver with CONFIG_SYS_I2C_MXC
2056 - enable bus 1 with CONFIG_SYS_I2C_MXC_I2C1
2057 - enable bus 2 with CONFIG_SYS_I2C_MXC_I2C2
2058 - enable bus 3 with CONFIG_SYS_I2C_MXC_I2C3
2059 - enable bus 4 with CONFIG_SYS_I2C_MXC_I2C4
2060 - define speed for bus 1 with CONFIG_SYS_MXC_I2C1_SPEED
2061 - define slave for bus 1 with CONFIG_SYS_MXC_I2C1_SLAVE
2062 - define speed for bus 2 with CONFIG_SYS_MXC_I2C2_SPEED
2063 - define slave for bus 2 with CONFIG_SYS_MXC_I2C2_SLAVE
2064 - define speed for bus 3 with CONFIG_SYS_MXC_I2C3_SPEED
2065 - define slave for bus 3 with CONFIG_SYS_MXC_I2C3_SLAVE
2066 - define speed for bus 4 with CONFIG_SYS_MXC_I2C4_SPEED
2067 - define slave for bus 4 with CONFIG_SYS_MXC_I2C4_SLAVE
2068 If those defines are not set, default value is 100000
2069 for speed, and 0 for slave.
2071 - drivers/i2c/rcar_i2c.c:
2072 - activate this driver with CONFIG_SYS_I2C_RCAR
2073 - This driver adds 4 i2c buses
2075 - CONFIG_SYS_RCAR_I2C0_BASE for setting the register channel 0
2076 - CONFIG_SYS_RCAR_I2C0_SPEED for for the speed channel 0
2077 - CONFIG_SYS_RCAR_I2C1_BASE for setting the register channel 1
2078 - CONFIG_SYS_RCAR_I2C1_SPEED for for the speed channel 1
2079 - CONFIG_SYS_RCAR_I2C2_BASE for setting the register channel 2
2080 - CONFIG_SYS_RCAR_I2C2_SPEED for for the speed channel 2
2081 - CONFIG_SYS_RCAR_I2C3_BASE for setting the register channel 3
2082 - CONFIG_SYS_RCAR_I2C3_SPEED for for the speed channel 3
2083 - CONFIF_SYS_RCAR_I2C_NUM_CONTROLLERS for number of i2c buses
2085 - drivers/i2c/sh_i2c.c:
2086 - activate this driver with CONFIG_SYS_I2C_SH
2087 - This driver adds from 2 to 5 i2c buses
2089 - CONFIG_SYS_I2C_SH_BASE0 for setting the register channel 0
2090 - CONFIG_SYS_I2C_SH_SPEED0 for for the speed channel 0
2091 - CONFIG_SYS_I2C_SH_BASE1 for setting the register channel 1
2092 - CONFIG_SYS_I2C_SH_SPEED1 for for the speed channel 1
2093 - CONFIG_SYS_I2C_SH_BASE2 for setting the register channel 2
2094 - CONFIG_SYS_I2C_SH_SPEED2 for for the speed channel 2
2095 - CONFIG_SYS_I2C_SH_BASE3 for setting the register channel 3
2096 - CONFIG_SYS_I2C_SH_SPEED3 for for the speed channel 3
2097 - CONFIG_SYS_I2C_SH_BASE4 for setting the register channel 4
2098 - CONFIG_SYS_I2C_SH_SPEED4 for for the speed channel 4
2099 - CONFIG_SYS_I2C_SH_NUM_CONTROLLERS for number of i2c buses
2101 - drivers/i2c/omap24xx_i2c.c
2102 - activate this driver with CONFIG_SYS_I2C_OMAP24XX
2103 - CONFIG_SYS_OMAP24_I2C_SPEED speed channel 0
2104 - CONFIG_SYS_OMAP24_I2C_SLAVE slave addr channel 0
2105 - CONFIG_SYS_OMAP24_I2C_SPEED1 speed channel 1
2106 - CONFIG_SYS_OMAP24_I2C_SLAVE1 slave addr channel 1
2107 - CONFIG_SYS_OMAP24_I2C_SPEED2 speed channel 2
2108 - CONFIG_SYS_OMAP24_I2C_SLAVE2 slave addr channel 2
2109 - CONFIG_SYS_OMAP24_I2C_SPEED3 speed channel 3
2110 - CONFIG_SYS_OMAP24_I2C_SLAVE3 slave addr channel 3
2111 - CONFIG_SYS_OMAP24_I2C_SPEED4 speed channel 4
2112 - CONFIG_SYS_OMAP24_I2C_SLAVE4 slave addr channel 4
2114 - drivers/i2c/zynq_i2c.c
2115 - activate this driver with CONFIG_SYS_I2C_ZYNQ
2116 - set CONFIG_SYS_I2C_ZYNQ_SPEED for speed setting
2117 - set CONFIG_SYS_I2C_ZYNQ_SLAVE for slave addr
2119 - drivers/i2c/s3c24x0_i2c.c:
2120 - activate this driver with CONFIG_SYS_I2C_S3C24X0
2121 - This driver adds i2c buses (11 for Exynos5250, Exynos5420
2122 9 i2c buses for Exynos4 and 1 for S3C24X0 SoCs from Samsung)
2123 with a fix speed from 100000 and the slave addr 0!
2125 - drivers/i2c/ihs_i2c.c
2126 - activate this driver with CONFIG_SYS_I2C_IHS
2127 - CONFIG_SYS_I2C_IHS_CH0 activate hardware channel 0
2128 - CONFIG_SYS_I2C_IHS_SPEED_0 speed channel 0
2129 - CONFIG_SYS_I2C_IHS_SLAVE_0 slave addr channel 0
2130 - CONFIG_SYS_I2C_IHS_CH1 activate hardware channel 1
2131 - CONFIG_SYS_I2C_IHS_SPEED_1 speed channel 1
2132 - CONFIG_SYS_I2C_IHS_SLAVE_1 slave addr channel 1
2133 - CONFIG_SYS_I2C_IHS_CH2 activate hardware channel 2
2134 - CONFIG_SYS_I2C_IHS_SPEED_2 speed channel 2
2135 - CONFIG_SYS_I2C_IHS_SLAVE_2 slave addr channel 2
2136 - CONFIG_SYS_I2C_IHS_CH3 activate hardware channel 3
2137 - CONFIG_SYS_I2C_IHS_SPEED_3 speed channel 3
2138 - CONFIG_SYS_I2C_IHS_SLAVE_3 slave addr channel 3
2139 - activate dual channel with CONFIG_SYS_I2C_IHS_DUAL
2140 - CONFIG_SYS_I2C_IHS_SPEED_0_1 speed channel 0_1
2141 - CONFIG_SYS_I2C_IHS_SLAVE_0_1 slave addr channel 0_1
2142 - CONFIG_SYS_I2C_IHS_SPEED_1_1 speed channel 1_1
2143 - CONFIG_SYS_I2C_IHS_SLAVE_1_1 slave addr channel 1_1
2144 - CONFIG_SYS_I2C_IHS_SPEED_2_1 speed channel 2_1
2145 - CONFIG_SYS_I2C_IHS_SLAVE_2_1 slave addr channel 2_1
2146 - CONFIG_SYS_I2C_IHS_SPEED_3_1 speed channel 3_1
2147 - CONFIG_SYS_I2C_IHS_SLAVE_3_1 slave addr channel 3_1
2151 CONFIG_SYS_NUM_I2C_BUSES
2152 Hold the number of i2c buses you want to use.
2154 CONFIG_SYS_I2C_DIRECT_BUS
2155 define this, if you don't use i2c muxes on your hardware.
2156 if CONFIG_SYS_I2C_MAX_HOPS is not defined or == 0 you can
2159 CONFIG_SYS_I2C_MAX_HOPS
2160 define how many muxes are maximal consecutively connected
2161 on one i2c bus. If you not use i2c muxes, omit this
2164 CONFIG_SYS_I2C_BUSES
2165 hold a list of buses you want to use, only used if
2166 CONFIG_SYS_I2C_DIRECT_BUS is not defined, for example
2167 a board with CONFIG_SYS_I2C_MAX_HOPS = 1 and
2168 CONFIG_SYS_NUM_I2C_BUSES = 9:
2170 CONFIG_SYS_I2C_BUSES {{0, {I2C_NULL_HOP}}, \
2171 {0, {{I2C_MUX_PCA9547, 0x70, 1}}}, \
2172 {0, {{I2C_MUX_PCA9547, 0x70, 2}}}, \
2173 {0, {{I2C_MUX_PCA9547, 0x70, 3}}}, \
2174 {0, {{I2C_MUX_PCA9547, 0x70, 4}}}, \
2175 {0, {{I2C_MUX_PCA9547, 0x70, 5}}}, \
2176 {1, {I2C_NULL_HOP}}, \
2177 {1, {{I2C_MUX_PCA9544, 0x72, 1}}}, \
2178 {1, {{I2C_MUX_PCA9544, 0x72, 2}}}, \
2182 bus 0 on adapter 0 without a mux
2183 bus 1 on adapter 0 with a PCA9547 on address 0x70 port 1
2184 bus 2 on adapter 0 with a PCA9547 on address 0x70 port 2
2185 bus 3 on adapter 0 with a PCA9547 on address 0x70 port 3
2186 bus 4 on adapter 0 with a PCA9547 on address 0x70 port 4
2187 bus 5 on adapter 0 with a PCA9547 on address 0x70 port 5
2188 bus 6 on adapter 1 without a mux
2189 bus 7 on adapter 1 with a PCA9544 on address 0x72 port 1
2190 bus 8 on adapter 1 with a PCA9544 on address 0x72 port 2
2192 If you do not have i2c muxes on your board, omit this define.
2194 - Legacy I2C Support:
2195 If you use the software i2c interface (CONFIG_SYS_I2C_SOFT)
2196 then the following macros need to be defined (examples are
2197 from include/configs/lwmon.h):
2201 (Optional). Any commands necessary to enable the I2C
2202 controller or configure ports.
2204 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
2208 (Only for MPC8260 CPU). The I/O port to use (the code
2209 assumes both bits are on the same port). Valid values
2210 are 0..3 for ports A..D.
2214 The code necessary to make the I2C data line active
2215 (driven). If the data line is open collector, this
2218 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
2222 The code necessary to make the I2C data line tri-stated
2223 (inactive). If the data line is open collector, this
2226 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
2230 Code that returns true if the I2C data line is high,
2233 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
2237 If <bit> is true, sets the I2C data line high. If it
2238 is false, it clears it (low).
2240 eg: #define I2C_SDA(bit) \
2241 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
2242 else immr->im_cpm.cp_pbdat &= ~PB_SDA
2246 If <bit> is true, sets the I2C clock line high. If it
2247 is false, it clears it (low).
2249 eg: #define I2C_SCL(bit) \
2250 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
2251 else immr->im_cpm.cp_pbdat &= ~PB_SCL
2255 This delay is invoked four times per clock cycle so this
2256 controls the rate of data transfer. The data rate thus
2257 is 1 / (I2C_DELAY * 4). Often defined to be something
2260 #define I2C_DELAY udelay(2)
2262 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
2264 If your arch supports the generic GPIO framework (asm/gpio.h),
2265 then you may alternatively define the two GPIOs that are to be
2266 used as SCL / SDA. Any of the previous I2C_xxx macros will
2267 have GPIO-based defaults assigned to them as appropriate.
2269 You should define these to the GPIO value as given directly to
2270 the generic GPIO functions.
2272 CONFIG_SYS_I2C_INIT_BOARD
2274 When a board is reset during an i2c bus transfer
2275 chips might think that the current transfer is still
2276 in progress. On some boards it is possible to access
2277 the i2c SCLK line directly, either by using the
2278 processor pin as a GPIO or by having a second pin
2279 connected to the bus. If this option is defined a
2280 custom i2c_init_board() routine in boards/xxx/board.c
2281 is run early in the boot sequence.
2283 CONFIG_I2C_MULTI_BUS
2285 This option allows the use of multiple I2C buses, each of which
2286 must have a controller. At any point in time, only one bus is
2287 active. To switch to a different bus, use the 'i2c dev' command.
2288 Note that bus numbering is zero-based.
2290 CONFIG_SYS_I2C_NOPROBES
2292 This option specifies a list of I2C devices that will be skipped
2293 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
2294 is set, specify a list of bus-device pairs. Otherwise, specify
2295 a 1D array of device addresses
2298 #undef CONFIG_I2C_MULTI_BUS
2299 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
2301 will skip addresses 0x50 and 0x68 on a board with one I2C bus
2303 #define CONFIG_I2C_MULTI_BUS
2304 #define CONFIG_SYS_I2C_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
2306 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
2308 CONFIG_SYS_SPD_BUS_NUM
2310 If defined, then this indicates the I2C bus number for DDR SPD.
2311 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
2313 CONFIG_SYS_RTC_BUS_NUM
2315 If defined, then this indicates the I2C bus number for the RTC.
2316 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
2318 CONFIG_SOFT_I2C_READ_REPEATED_START
2320 defining this will force the i2c_read() function in
2321 the soft_i2c driver to perform an I2C repeated start
2322 between writing the address pointer and reading the
2323 data. If this define is omitted the default behaviour
2324 of doing a stop-start sequence will be used. Most I2C
2325 devices can use either method, but some require one or
2328 - SPI Support: CONFIG_SPI
2330 Enables SPI driver (so far only tested with
2331 SPI EEPROM, also an instance works with Crystal A/D and
2332 D/As on the SACSng board)
2336 Enables the driver for SPI controller on SuperH. Currently
2337 only SH7757 is supported.
2341 Enables a software (bit-bang) SPI driver rather than
2342 using hardware support. This is a general purpose
2343 driver that only requires three general I/O port pins
2344 (two outputs, one input) to function. If this is
2345 defined, the board configuration must define several
2346 SPI configuration items (port pins to use, etc). For
2347 an example, see include/configs/sacsng.h.
2351 Enables a hardware SPI driver for general-purpose reads
2352 and writes. As with CONFIG_SOFT_SPI, the board configuration
2353 must define a list of chip-select function pointers.
2354 Currently supported on some MPC8xxx processors. For an
2355 example, see include/configs/mpc8349emds.h.
2359 Enables the driver for the SPI controllers on i.MX and MXC
2360 SoCs. Currently i.MX31/35/51 are supported.
2362 CONFIG_SYS_SPI_MXC_WAIT
2363 Timeout for waiting until spi transfer completed.
2364 default: (CONFIG_SYS_HZ/100) /* 10 ms */
2366 - FPGA Support: CONFIG_FPGA
2368 Enables FPGA subsystem.
2370 CONFIG_FPGA_<vendor>
2372 Enables support for specific chip vendors.
2375 CONFIG_FPGA_<family>
2377 Enables support for FPGA family.
2378 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
2382 Specify the number of FPGA devices to support.
2384 CONFIG_SYS_FPGA_PROG_FEEDBACK
2386 Enable printing of hash marks during FPGA configuration.
2388 CONFIG_SYS_FPGA_CHECK_BUSY
2390 Enable checks on FPGA configuration interface busy
2391 status by the configuration function. This option
2392 will require a board or device specific function to
2397 If defined, a function that provides delays in the FPGA
2398 configuration driver.
2400 CONFIG_SYS_FPGA_CHECK_CTRLC
2401 Allow Control-C to interrupt FPGA configuration
2403 CONFIG_SYS_FPGA_CHECK_ERROR
2405 Check for configuration errors during FPGA bitfile
2406 loading. For example, abort during Virtex II
2407 configuration if the INIT_B line goes low (which
2408 indicated a CRC error).
2410 CONFIG_SYS_FPGA_WAIT_INIT
2412 Maximum time to wait for the INIT_B line to de-assert
2413 after PROB_B has been de-asserted during a Virtex II
2414 FPGA configuration sequence. The default time is 500
2417 CONFIG_SYS_FPGA_WAIT_BUSY
2419 Maximum time to wait for BUSY to de-assert during
2420 Virtex II FPGA configuration. The default is 5 ms.
2422 CONFIG_SYS_FPGA_WAIT_CONFIG
2424 Time to wait after FPGA configuration. The default is
2427 - Configuration Management:
2430 Some SoCs need special image types (e.g. U-Boot binary
2431 with a special header) as build targets. By defining
2432 CONFIG_BUILD_TARGET in the SoC / board header, this
2433 special image will be automatically built upon calling
2438 If defined, this string will be added to the U-Boot
2439 version information (U_BOOT_VERSION)
2441 - Vendor Parameter Protection:
2443 U-Boot considers the values of the environment
2444 variables "serial#" (Board Serial Number) and
2445 "ethaddr" (Ethernet Address) to be parameters that
2446 are set once by the board vendor / manufacturer, and
2447 protects these variables from casual modification by
2448 the user. Once set, these variables are read-only,
2449 and write or delete attempts are rejected. You can
2450 change this behaviour:
2452 If CONFIG_ENV_OVERWRITE is #defined in your config
2453 file, the write protection for vendor parameters is
2454 completely disabled. Anybody can change or delete
2457 Alternatively, if you define _both_ an ethaddr in the
2458 default env _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2459 Ethernet address is installed in the environment,
2460 which can be changed exactly ONCE by the user. [The
2461 serial# is unaffected by this, i. e. it remains
2464 The same can be accomplished in a more flexible way
2465 for any variable by configuring the type of access
2466 to allow for those variables in the ".flags" variable
2467 or define CONFIG_ENV_FLAGS_LIST_STATIC.
2472 Define this variable to enable the reservation of
2473 "protected RAM", i. e. RAM which is not overwritten
2474 by U-Boot. Define CONFIG_PRAM to hold the number of
2475 kB you want to reserve for pRAM. You can overwrite
2476 this default value by defining an environment
2477 variable "pram" to the number of kB you want to
2478 reserve. Note that the board info structure will
2479 still show the full amount of RAM. If pRAM is
2480 reserved, a new environment variable "mem" will
2481 automatically be defined to hold the amount of
2482 remaining RAM in a form that can be passed as boot
2483 argument to Linux, for instance like that:
2485 setenv bootargs ... mem=\${mem}
2488 This way you can tell Linux not to use this memory,
2489 either, which results in a memory region that will
2490 not be affected by reboots.
2492 *WARNING* If your board configuration uses automatic
2493 detection of the RAM size, you must make sure that
2494 this memory test is non-destructive. So far, the
2495 following board configurations are known to be
2498 IVMS8, IVML24, SPD8xx, TQM8xxL,
2499 HERMES, IP860, RPXlite, LWMON,
2502 - Access to physical memory region (> 4GB)
2503 Some basic support is provided for operations on memory not
2504 normally accessible to U-Boot - e.g. some architectures
2505 support access to more than 4GB of memory on 32-bit
2506 machines using physical address extension or similar.
2507 Define CONFIG_PHYSMEM to access this basic support, which
2508 currently only supports clearing the memory.
2513 Define this variable to stop the system in case of a
2514 fatal error, so that you have to reset it manually.
2515 This is probably NOT a good idea for an embedded
2516 system where you want the system to reboot
2517 automatically as fast as possible, but it may be
2518 useful during development since you can try to debug
2519 the conditions that lead to the situation.
2521 CONFIG_NET_RETRY_COUNT
2523 This variable defines the number of retries for
2524 network operations like ARP, RARP, TFTP, or BOOTP
2525 before giving up the operation. If not defined, a
2526 default value of 5 is used.
2530 Timeout waiting for an ARP reply in milliseconds.
2534 Timeout in milliseconds used in NFS protocol.
2535 If you encounter "ERROR: Cannot umount" in nfs command,
2536 try longer timeout such as
2537 #define CONFIG_NFS_TIMEOUT 10000UL
2539 - Command Interpreter:
2540 CONFIG_AUTO_COMPLETE
2542 Enable auto completion of commands using TAB.
2544 CONFIG_SYS_PROMPT_HUSH_PS2
2546 This defines the secondary prompt string, which is
2547 printed when the command interpreter needs more input
2548 to complete a command. Usually "> ".
2552 In the current implementation, the local variables
2553 space and global environment variables space are
2554 separated. Local variables are those you define by
2555 simply typing `name=value'. To access a local
2556 variable later on, you have write `$name' or
2557 `${name}'; to execute the contents of a variable
2558 directly type `$name' at the command prompt.
2560 Global environment variables are those you use
2561 setenv/printenv to work with. To run a command stored
2562 in such a variable, you need to use the run command,
2563 and you must not use the '$' sign to access them.
2565 To store commands and special characters in a
2566 variable, please use double quotation marks
2567 surrounding the whole text of the variable, instead
2568 of the backslashes before semicolons and special
2571 - Command Line Editing and History:
2572 CONFIG_CMDLINE_EDITING
2574 Enable editing and History functions for interactive
2575 command line input operations
2577 - Command Line PS1/PS2 support:
2578 CONFIG_CMDLINE_PS_SUPPORT
2580 Enable support for changing the command prompt string
2581 at run-time. Only static string is supported so far.
2582 The string is obtained from environment variables PS1
2585 - Default Environment:
2586 CONFIG_EXTRA_ENV_SETTINGS
2588 Define this to contain any number of null terminated
2589 strings (variable = value pairs) that will be part of
2590 the default environment compiled into the boot image.
2592 For example, place something like this in your
2593 board's config file:
2595 #define CONFIG_EXTRA_ENV_SETTINGS \
2599 Warning: This method is based on knowledge about the
2600 internal format how the environment is stored by the
2601 U-Boot code. This is NOT an official, exported
2602 interface! Although it is unlikely that this format
2603 will change soon, there is no guarantee either.
2604 You better know what you are doing here.
2606 Note: overly (ab)use of the default environment is
2607 discouraged. Make sure to check other ways to preset
2608 the environment like the "source" command or the
2611 CONFIG_ENV_VARS_UBOOT_CONFIG
2613 Define this in order to add variables describing the
2614 U-Boot build configuration to the default environment.
2615 These will be named arch, cpu, board, vendor, and soc.
2617 Enabling this option will cause the following to be defined:
2625 CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG
2627 Define this in order to add variables describing certain
2628 run-time determined information about the hardware to the
2629 environment. These will be named board_name, board_rev.
2631 CONFIG_DELAY_ENVIRONMENT
2633 Normally the environment is loaded when the board is
2634 initialised so that it is available to U-Boot. This inhibits
2635 that so that the environment is not available until
2636 explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL
2637 this is instead controlled by the value of
2638 /config/load-environment.
2640 - DataFlash Support:
2641 CONFIG_HAS_DATAFLASH
2643 Defining this option enables DataFlash features and
2644 allows to read/write in Dataflash via the standard
2647 - Serial Flash support
2650 Defining this option enables SPI flash commands
2651 'sf probe/read/write/erase/update'.
2653 Usage requires an initial 'probe' to define the serial
2654 flash parameters, followed by read/write/erase/update
2657 The following defaults may be provided by the platform
2658 to handle the common case when only a single serial
2659 flash is present on the system.
2661 CONFIG_SF_DEFAULT_BUS Bus identifier
2662 CONFIG_SF_DEFAULT_CS Chip-select
2663 CONFIG_SF_DEFAULT_MODE (see include/spi.h)
2664 CONFIG_SF_DEFAULT_SPEED in Hz
2668 Define this option to include a destructive SPI flash
2671 CONFIG_SF_DUAL_FLASH Dual flash memories
2673 Define this option to use dual flash support where two flash
2674 memories can be connected with a given cs line.
2675 Currently Xilinx Zynq qspi supports these type of connections.
2677 - SystemACE Support:
2680 Adding this option adds support for Xilinx SystemACE
2681 chips attached via some sort of local bus. The address
2682 of the chip must also be defined in the
2683 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
2685 #define CONFIG_SYSTEMACE
2686 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
2688 When SystemACE support is added, the "ace" device type
2689 becomes available to the fat commands, i.e. fatls.
2691 - TFTP Fixed UDP Port:
2694 If this is defined, the environment variable tftpsrcp
2695 is used to supply the TFTP UDP source port value.
2696 If tftpsrcp isn't defined, the normal pseudo-random port
2697 number generator is used.
2699 Also, the environment variable tftpdstp is used to supply
2700 the TFTP UDP destination port value. If tftpdstp isn't
2701 defined, the normal port 69 is used.
2703 The purpose for tftpsrcp is to allow a TFTP server to
2704 blindly start the TFTP transfer using the pre-configured
2705 target IP address and UDP port. This has the effect of
2706 "punching through" the (Windows XP) firewall, allowing
2707 the remainder of the TFTP transfer to proceed normally.
2708 A better solution is to properly configure the firewall,
2709 but sometimes that is not allowed.
2714 Enable the hash verify command (hash -v). This adds to code
2717 Note: There is also a sha1sum command, which should perhaps
2718 be deprecated in favour of 'hash sha1'.
2720 - Freescale i.MX specific commands:
2721 CONFIG_CMD_HDMIDETECT
2722 This enables 'hdmidet' command which returns true if an
2723 HDMI monitor is detected. This command is i.MX 6 specific.
2725 - bootcount support:
2726 CONFIG_BOOTCOUNT_LIMIT
2728 This enables the bootcounter support, see:
2729 http://www.denx.de/wiki/DULG/UBootBootCountLimit
2732 enable special bootcounter support on at91sam9xe based boards.
2734 enable special bootcounter support on da850 based boards.
2735 CONFIG_BOOTCOUNT_RAM
2736 enable support for the bootcounter in RAM
2737 CONFIG_BOOTCOUNT_I2C
2738 enable support for the bootcounter on an i2c (like RTC) device.
2739 CONFIG_SYS_I2C_RTC_ADDR = i2c chip address
2740 CONFIG_SYS_BOOTCOUNT_ADDR = i2c addr which is used for
2742 CONFIG_BOOTCOUNT_ALEN = address len
2744 - Show boot progress:
2745 CONFIG_SHOW_BOOT_PROGRESS
2747 Defining this option allows to add some board-
2748 specific code (calling a user-provided function
2749 "show_boot_progress(int)") that enables you to show
2750 the system's boot progress on some display (for
2751 example, some LED's) on your board. At the moment,
2752 the following checkpoints are implemented:
2755 Legacy uImage format:
2758 1 common/cmd_bootm.c before attempting to boot an image
2759 -1 common/cmd_bootm.c Image header has bad magic number
2760 2 common/cmd_bootm.c Image header has correct magic number
2761 -2 common/cmd_bootm.c Image header has bad checksum
2762 3 common/cmd_bootm.c Image header has correct checksum
2763 -3 common/cmd_bootm.c Image data has bad checksum
2764 4 common/cmd_bootm.c Image data has correct checksum
2765 -4 common/cmd_bootm.c Image is for unsupported architecture
2766 5 common/cmd_bootm.c Architecture check OK
2767 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
2768 6 common/cmd_bootm.c Image Type check OK
2769 -6 common/cmd_bootm.c gunzip uncompression error
2770 -7 common/cmd_bootm.c Unimplemented compression type
2771 7 common/cmd_bootm.c Uncompression OK
2772 8 common/cmd_bootm.c No uncompress/copy overwrite error
2773 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
2775 9 common/image.c Start initial ramdisk verification
2776 -10 common/image.c Ramdisk header has bad magic number
2777 -11 common/image.c Ramdisk header has bad checksum
2778 10 common/image.c Ramdisk header is OK
2779 -12 common/image.c Ramdisk data has bad checksum
2780 11 common/image.c Ramdisk data has correct checksum
2781 12 common/image.c Ramdisk verification complete, start loading
2782 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
2783 13 common/image.c Start multifile image verification
2784 14 common/image.c No initial ramdisk, no multifile, continue.
2786 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
2788 -30 arch/powerpc/lib/board.c Fatal error, hang the system
2789 -31 post/post.c POST test failed, detected by post_output_backlog()
2790 -32 post/post.c POST test failed, detected by post_run_single()
2792 34 common/cmd_doc.c before loading a Image from a DOC device
2793 -35 common/cmd_doc.c Bad usage of "doc" command
2794 35 common/cmd_doc.c correct usage of "doc" command
2795 -36 common/cmd_doc.c No boot device
2796 36 common/cmd_doc.c correct boot device
2797 -37 common/cmd_doc.c Unknown Chip ID on boot device
2798 37 common/cmd_doc.c correct chip ID found, device available
2799 -38 common/cmd_doc.c Read Error on boot device
2800 38 common/cmd_doc.c reading Image header from DOC device OK
2801 -39 common/cmd_doc.c Image header has bad magic number
2802 39 common/cmd_doc.c Image header has correct magic number
2803 -40 common/cmd_doc.c Error reading Image from DOC device
2804 40 common/cmd_doc.c Image header has correct magic number
2805 41 common/cmd_ide.c before loading a Image from a IDE device
2806 -42 common/cmd_ide.c Bad usage of "ide" command
2807 42 common/cmd_ide.c correct usage of "ide" command
2808 -43 common/cmd_ide.c No boot device
2809 43 common/cmd_ide.c boot device found
2810 -44 common/cmd_ide.c Device not available
2811 44 common/cmd_ide.c Device available
2812 -45 common/cmd_ide.c wrong partition selected
2813 45 common/cmd_ide.c partition selected
2814 -46 common/cmd_ide.c Unknown partition table
2815 46 common/cmd_ide.c valid partition table found
2816 -47 common/cmd_ide.c Invalid partition type
2817 47 common/cmd_ide.c correct partition type
2818 -48 common/cmd_ide.c Error reading Image Header on boot device
2819 48 common/cmd_ide.c reading Image Header from IDE device OK
2820 -49 common/cmd_ide.c Image header has bad magic number
2821 49 common/cmd_ide.c Image header has correct magic number
2822 -50 common/cmd_ide.c Image header has bad checksum
2823 50 common/cmd_ide.c Image header has correct checksum
2824 -51 common/cmd_ide.c Error reading Image from IDE device
2825 51 common/cmd_ide.c reading Image from IDE device OK
2826 52 common/cmd_nand.c before loading a Image from a NAND device
2827 -53 common/cmd_nand.c Bad usage of "nand" command
2828 53 common/cmd_nand.c correct usage of "nand" command
2829 -54 common/cmd_nand.c No boot device
2830 54 common/cmd_nand.c boot device found
2831 -55 common/cmd_nand.c Unknown Chip ID on boot device
2832 55 common/cmd_nand.c correct chip ID found, device available
2833 -56 common/cmd_nand.c Error reading Image Header on boot device
2834 56 common/cmd_nand.c reading Image Header from NAND device OK
2835 -57 common/cmd_nand.c Image header has bad magic number
2836 57 common/cmd_nand.c Image header has correct magic number
2837 -58 common/cmd_nand.c Error reading Image from NAND device
2838 58 common/cmd_nand.c reading Image from NAND device OK
2840 -60 common/env_common.c Environment has a bad CRC, using default
2842 64 net/eth.c starting with Ethernet configuration.
2843 -64 net/eth.c no Ethernet found.
2844 65 net/eth.c Ethernet found.
2846 -80 common/cmd_net.c usage wrong
2847 80 common/cmd_net.c before calling net_loop()
2848 -81 common/cmd_net.c some error in net_loop() occurred
2849 81 common/cmd_net.c net_loop() back without error
2850 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
2851 82 common/cmd_net.c trying automatic boot
2852 83 common/cmd_net.c running "source" command
2853 -83 common/cmd_net.c some error in automatic boot or "source" command
2854 84 common/cmd_net.c end without errors
2859 100 common/cmd_bootm.c Kernel FIT Image has correct format
2860 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
2861 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
2862 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
2863 102 common/cmd_bootm.c Kernel unit name specified
2864 -103 common/cmd_bootm.c Can't get kernel subimage node offset
2865 103 common/cmd_bootm.c Found configuration node
2866 104 common/cmd_bootm.c Got kernel subimage node offset
2867 -104 common/cmd_bootm.c Kernel subimage hash verification failed
2868 105 common/cmd_bootm.c Kernel subimage hash verification OK
2869 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
2870 106 common/cmd_bootm.c Architecture check OK
2871 -106 common/cmd_bootm.c Kernel subimage has wrong type
2872 107 common/cmd_bootm.c Kernel subimage type OK
2873 -107 common/cmd_bootm.c Can't get kernel subimage data/size
2874 108 common/cmd_bootm.c Got kernel subimage data/size
2875 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
2876 -109 common/cmd_bootm.c Can't get kernel subimage type
2877 -110 common/cmd_bootm.c Can't get kernel subimage comp
2878 -111 common/cmd_bootm.c Can't get kernel subimage os
2879 -112 common/cmd_bootm.c Can't get kernel subimage load address
2880 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
2882 120 common/image.c Start initial ramdisk verification
2883 -120 common/image.c Ramdisk FIT image has incorrect format
2884 121 common/image.c Ramdisk FIT image has correct format
2885 122 common/image.c No ramdisk subimage unit name, using configuration
2886 -122 common/image.c Can't get configuration for ramdisk subimage
2887 123 common/image.c Ramdisk unit name specified
2888 -124 common/image.c Can't get ramdisk subimage node offset
2889 125 common/image.c Got ramdisk subimage node offset
2890 -125 common/image.c Ramdisk subimage hash verification failed
2891 126 common/image.c Ramdisk subimage hash verification OK
2892 -126 common/image.c Ramdisk subimage for unsupported architecture
2893 127 common/image.c Architecture check OK
2894 -127 common/image.c Can't get ramdisk subimage data/size
2895 128 common/image.c Got ramdisk subimage data/size
2896 129 common/image.c Can't get ramdisk load address
2897 -129 common/image.c Got ramdisk load address
2899 -130 common/cmd_doc.c Incorrect FIT image format
2900 131 common/cmd_doc.c FIT image format OK
2902 -140 common/cmd_ide.c Incorrect FIT image format
2903 141 common/cmd_ide.c FIT image format OK
2905 -150 common/cmd_nand.c Incorrect FIT image format
2906 151 common/cmd_nand.c FIT image format OK
2908 - legacy image format:
2909 CONFIG_IMAGE_FORMAT_LEGACY
2910 enables the legacy image format support in U-Boot.
2913 enabled if CONFIG_FIT_SIGNATURE is not defined.
2915 CONFIG_DISABLE_IMAGE_LEGACY
2916 disable the legacy image format
2918 This define is introduced, as the legacy image format is
2919 enabled per default for backward compatibility.
2921 - Standalone program support:
2922 CONFIG_STANDALONE_LOAD_ADDR
2924 This option defines a board specific value for the
2925 address where standalone program gets loaded, thus
2926 overwriting the architecture dependent default
2929 - Frame Buffer Address:
2932 Define CONFIG_FB_ADDR if you want to use specific
2933 address for frame buffer. This is typically the case
2934 when using a graphics controller has separate video
2935 memory. U-Boot will then place the frame buffer at
2936 the given address instead of dynamically reserving it
2937 in system RAM by calling lcd_setmem(), which grabs
2938 the memory for the frame buffer depending on the
2939 configured panel size.
2941 Please see board_init_f function.
2943 - Automatic software updates via TFTP server
2945 CONFIG_UPDATE_TFTP_CNT_MAX
2946 CONFIG_UPDATE_TFTP_MSEC_MAX
2948 These options enable and control the auto-update feature;
2949 for a more detailed description refer to doc/README.update.
2951 - MTD Support (mtdparts command, UBI support)
2954 Adds the MTD device infrastructure from the Linux kernel.
2955 Needed for mtdparts command support.
2957 CONFIG_MTD_PARTITIONS
2959 Adds the MTD partitioning infrastructure from the Linux
2960 kernel. Needed for UBI support.
2965 Adds commands for interacting with MTD partitions formatted
2966 with the UBI flash translation layer
2968 Requires also defining CONFIG_RBTREE
2970 CONFIG_UBI_SILENCE_MSG
2972 Make the verbose messages from UBI stop printing. This leaves
2973 warnings and errors enabled.
2976 CONFIG_MTD_UBI_WL_THRESHOLD
2977 This parameter defines the maximum difference between the highest
2978 erase counter value and the lowest erase counter value of eraseblocks
2979 of UBI devices. When this threshold is exceeded, UBI starts performing
2980 wear leveling by means of moving data from eraseblock with low erase
2981 counter to eraseblocks with high erase counter.
2983 The default value should be OK for SLC NAND flashes, NOR flashes and
2984 other flashes which have eraseblock life-cycle 100000 or more.
2985 However, in case of MLC NAND flashes which typically have eraseblock
2986 life-cycle less than 10000, the threshold should be lessened (e.g.,
2987 to 128 or 256, although it does not have to be power of 2).
2991 CONFIG_MTD_UBI_BEB_LIMIT
2992 This option specifies the maximum bad physical eraseblocks UBI
2993 expects on the MTD device (per 1024 eraseblocks). If the
2994 underlying flash does not admit of bad eraseblocks (e.g. NOR
2995 flash), this value is ignored.
2997 NAND datasheets often specify the minimum and maximum NVM
2998 (Number of Valid Blocks) for the flashes' endurance lifetime.
2999 The maximum expected bad eraseblocks per 1024 eraseblocks
3000 then can be calculated as "1024 * (1 - MinNVB / MaxNVB)",
3001 which gives 20 for most NANDs (MaxNVB is basically the total
3002 count of eraseblocks on the chip).
3004 To put it differently, if this value is 20, UBI will try to
3005 reserve about 1.9% of physical eraseblocks for bad blocks
3006 handling. And that will be 1.9% of eraseblocks on the entire
3007 NAND chip, not just the MTD partition UBI attaches. This means
3008 that if you have, say, a NAND flash chip admits maximum 40 bad
3009 eraseblocks, and it is split on two MTD partitions of the same
3010 size, UBI will reserve 40 eraseblocks when attaching a
3015 CONFIG_MTD_UBI_FASTMAP
3016 Fastmap is a mechanism which allows attaching an UBI device
3017 in nearly constant time. Instead of scanning the whole MTD device it
3018 only has to locate a checkpoint (called fastmap) on the device.
3019 The on-flash fastmap contains all information needed to attach
3020 the device. Using fastmap makes only sense on large devices where
3021 attaching by scanning takes long. UBI will not automatically install
3022 a fastmap on old images, but you can set the UBI parameter
3023 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT to 1 if you want so. Please note
3024 that fastmap-enabled images are still usable with UBI implementations
3025 without fastmap support. On typical flash devices the whole fastmap
3026 fits into one PEB. UBI will reserve PEBs to hold two fastmaps.
3028 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT
3029 Set this parameter to enable fastmap automatically on images
3033 CONFIG_MTD_UBI_FM_DEBUG
3034 Enable UBI fastmap debug
3040 Adds commands for interacting with UBI volumes formatted as
3041 UBIFS. UBIFS is read-only in u-boot.
3043 Requires UBI support as well as CONFIG_LZO
3045 CONFIG_UBIFS_SILENCE_MSG
3047 Make the verbose messages from UBIFS stop printing. This leaves
3048 warnings and errors enabled.
3052 Enable building of SPL globally.
3055 LDSCRIPT for linking the SPL binary.
3057 CONFIG_SPL_MAX_FOOTPRINT
3058 Maximum size in memory allocated to the SPL, BSS included.
3059 When defined, the linker checks that the actual memory
3060 used by SPL from _start to __bss_end does not exceed it.
3061 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3062 must not be both defined at the same time.
3065 Maximum size of the SPL image (text, data, rodata, and
3066 linker lists sections), BSS excluded.
3067 When defined, the linker checks that the actual size does
3070 CONFIG_SPL_TEXT_BASE
3071 TEXT_BASE for linking the SPL binary.
3073 CONFIG_SPL_RELOC_TEXT_BASE
3074 Address to relocate to. If unspecified, this is equal to
3075 CONFIG_SPL_TEXT_BASE (i.e. no relocation is done).
3077 CONFIG_SPL_BSS_START_ADDR
3078 Link address for the BSS within the SPL binary.
3080 CONFIG_SPL_BSS_MAX_SIZE
3081 Maximum size in memory allocated to the SPL BSS.
3082 When defined, the linker checks that the actual memory used
3083 by SPL from __bss_start to __bss_end does not exceed it.
3084 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3085 must not be both defined at the same time.
3088 Adress of the start of the stack SPL will use
3090 CONFIG_SPL_PANIC_ON_RAW_IMAGE
3091 When defined, SPL will panic() if the image it has
3092 loaded does not have a signature.
3093 Defining this is useful when code which loads images
3094 in SPL cannot guarantee that absolutely all read errors
3096 An example is the LPC32XX MLC NAND driver, which will
3097 consider that a completely unreadable NAND block is bad,
3098 and thus should be skipped silently.
3100 CONFIG_SPL_RELOC_STACK
3101 Adress of the start of the stack SPL will use after
3102 relocation. If unspecified, this is equal to
3105 CONFIG_SYS_SPL_MALLOC_START
3106 Starting address of the malloc pool used in SPL.
3107 When this option is set the full malloc is used in SPL and
3108 it is set up by spl_init() and before that, the simple malloc()
3109 can be used if CONFIG_SYS_MALLOC_F is defined.
3111 CONFIG_SYS_SPL_MALLOC_SIZE
3112 The size of the malloc pool used in SPL.
3114 CONFIG_SPL_FRAMEWORK
3115 Enable the SPL framework under common/. This framework
3116 supports MMC, NAND and YMODEM loading of U-Boot and NAND
3117 NAND loading of the Linux Kernel.
3120 Enable booting directly to an OS from SPL.
3121 See also: doc/README.falcon
3123 CONFIG_SPL_DISPLAY_PRINT
3124 For ARM, enable an optional function to print more information
3125 about the running system.
3127 CONFIG_SPL_INIT_MINIMAL
3128 Arch init code should be built for a very small image
3130 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_PARTITION
3131 Partition on the MMC to load U-Boot from when the MMC is being
3134 CONFIG_SYS_MMCSD_RAW_MODE_KERNEL_SECTOR
3135 Sector to load kernel uImage from when MMC is being
3136 used in raw mode (for Falcon mode)
3138 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTOR,
3139 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTORS
3140 Sector and number of sectors to load kernel argument
3141 parameters from when MMC is being used in raw mode
3144 CONFIG_SYS_MMCSD_FS_BOOT_PARTITION
3145 Partition on the MMC to load U-Boot from when the MMC is being
3148 CONFIG_SPL_FS_LOAD_PAYLOAD_NAME
3149 Filename to read to load U-Boot when reading from filesystem
3151 CONFIG_SPL_FS_LOAD_KERNEL_NAME
3152 Filename to read to load kernel uImage when reading
3153 from filesystem (for Falcon mode)
3155 CONFIG_SPL_FS_LOAD_ARGS_NAME
3156 Filename to read to load kernel argument parameters
3157 when reading from filesystem (for Falcon mode)
3159 CONFIG_SPL_MPC83XX_WAIT_FOR_NAND
3160 Set this for NAND SPL on PPC mpc83xx targets, so that
3161 start.S waits for the rest of the SPL to load before
3162 continuing (the hardware starts execution after just
3163 loading the first page rather than the full 4K).
3165 CONFIG_SPL_SKIP_RELOCATE
3166 Avoid SPL relocation
3168 CONFIG_SPL_NAND_BASE
3169 Include nand_base.c in the SPL. Requires
3170 CONFIG_SPL_NAND_DRIVERS.
3172 CONFIG_SPL_NAND_DRIVERS
3173 SPL uses normal NAND drivers, not minimal drivers.
3176 Include standard software ECC in the SPL
3178 CONFIG_SPL_NAND_SIMPLE
3179 Support for NAND boot using simple NAND drivers that
3180 expose the cmd_ctrl() interface.
3183 Support for a lightweight UBI (fastmap) scanner and
3186 CONFIG_SPL_NAND_RAW_ONLY
3187 Support to boot only raw u-boot.bin images. Use this only
3188 if you need to save space.
3190 CONFIG_SPL_COMMON_INIT_DDR
3191 Set for common ddr init with serial presence detect in
3194 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
3195 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
3196 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
3197 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
3198 CONFIG_SYS_NAND_ECCBYTES
3199 Defines the size and behavior of the NAND that SPL uses
3202 CONFIG_SPL_NAND_BOOT
3203 Add support NAND boot
3205 CONFIG_SYS_NAND_U_BOOT_OFFS
3206 Location in NAND to read U-Boot from
3208 CONFIG_SYS_NAND_U_BOOT_DST
3209 Location in memory to load U-Boot to
3211 CONFIG_SYS_NAND_U_BOOT_SIZE
3212 Size of image to load
3214 CONFIG_SYS_NAND_U_BOOT_START
3215 Entry point in loaded image to jump to
3217 CONFIG_SYS_NAND_HW_ECC_OOBFIRST
3218 Define this if you need to first read the OOB and then the
3219 data. This is used, for example, on davinci platforms.
3221 CONFIG_SPL_OMAP3_ID_NAND
3222 Support for an OMAP3-specific set of functions to return the
3223 ID and MFR of the first attached NAND chip, if present.
3225 CONFIG_SPL_RAM_DEVICE
3226 Support for running image already present in ram, in SPL binary
3229 Image offset to which the SPL should be padded before appending
3230 the SPL payload. By default, this is defined as
3231 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3232 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3233 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3236 Final target image containing SPL and payload. Some SPLs
3237 use an arch-specific makefile fragment instead, for
3238 example if more than one image needs to be produced.
3240 CONFIG_FIT_SPL_PRINT
3241 Printing information about a FIT image adds quite a bit of
3242 code to SPL. So this is normally disabled in SPL. Use this
3243 option to re-enable it. This will affect the output of the
3244 bootm command when booting a FIT image.
3248 Enable building of TPL globally.
3251 Image offset to which the TPL should be padded before appending
3252 the TPL payload. By default, this is defined as
3253 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3254 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3255 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3257 - Interrupt support (PPC):
3259 There are common interrupt_init() and timer_interrupt()
3260 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
3261 for CPU specific initialization. interrupt_init_cpu()
3262 should set decrementer_count to appropriate value. If
3263 CPU resets decrementer automatically after interrupt
3264 (ppc4xx) it should set decrementer_count to zero.
3265 timer_interrupt() calls timer_interrupt_cpu() for CPU
3266 specific handling. If board has watchdog / status_led
3267 / other_activity_monitor it works automatically from
3268 general timer_interrupt().
3271 Board initialization settings:
3272 ------------------------------
3274 During Initialization u-boot calls a number of board specific functions
3275 to allow the preparation of board specific prerequisites, e.g. pin setup
3276 before drivers are initialized. To enable these callbacks the
3277 following configuration macros have to be defined. Currently this is
3278 architecture specific, so please check arch/your_architecture/lib/board.c
3279 typically in board_init_f() and board_init_r().
3281 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
3282 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
3283 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
3284 - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
3286 Configuration Settings:
3287 -----------------------
3289 - CONFIG_SYS_SUPPORT_64BIT_DATA: Defined automatically if compiled as 64-bit.
3290 Optionally it can be defined to support 64-bit memory commands.
3292 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
3293 undefine this when you're short of memory.
3295 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
3296 width of the commands listed in the 'help' command output.
3298 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
3299 prompt for user input.
3301 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
3303 - CONFIG_SYS_PBSIZE: Buffer size for Console output
3305 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
3307 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
3308 the application (usually a Linux kernel) when it is
3311 - CONFIG_SYS_BAUDRATE_TABLE:
3312 List of legal baudrate settings for this board.
3314 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
3315 Begin and End addresses of the area used by the
3318 - CONFIG_SYS_ALT_MEMTEST:
3319 Enable an alternate, more extensive memory test.
3321 - CONFIG_SYS_MEMTEST_SCRATCH:
3322 Scratch address used by the alternate memory test
3323 You only need to set this if address zero isn't writeable
3325 - CONFIG_SYS_MEM_RESERVE_SECURE
3326 Only implemented for ARMv8 for now.
3327 If defined, the size of CONFIG_SYS_MEM_RESERVE_SECURE memory
3328 is substracted from total RAM and won't be reported to OS.
3329 This memory can be used as secure memory. A variable
3330 gd->arch.secure_ram is used to track the location. In systems
3331 the RAM base is not zero, or RAM is divided into banks,
3332 this variable needs to be recalcuated to get the address.
3334 - CONFIG_SYS_MEM_TOP_HIDE:
3335 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
3336 this specified memory area will get subtracted from the top
3337 (end) of RAM and won't get "touched" at all by U-Boot. By
3338 fixing up gd->ram_size the Linux kernel should gets passed
3339 the now "corrected" memory size and won't touch it either.
3340 This should work for arch/ppc and arch/powerpc. Only Linux
3341 board ports in arch/powerpc with bootwrapper support that
3342 recalculate the memory size from the SDRAM controller setup
3343 will have to get fixed in Linux additionally.
3345 This option can be used as a workaround for the 440EPx/GRx
3346 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
3349 WARNING: Please make sure that this value is a multiple of
3350 the Linux page size (normally 4k). If this is not the case,
3351 then the end address of the Linux memory will be located at a
3352 non page size aligned address and this could cause major
3355 - CONFIG_SYS_LOADS_BAUD_CHANGE:
3356 Enable temporary baudrate change while serial download
3358 - CONFIG_SYS_SDRAM_BASE:
3359 Physical start address of SDRAM. _Must_ be 0 here.
3361 - CONFIG_SYS_FLASH_BASE:
3362 Physical start address of Flash memory.
3364 - CONFIG_SYS_MONITOR_BASE:
3365 Physical start address of boot monitor code (set by
3366 make config files to be same as the text base address
3367 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
3368 CONFIG_SYS_FLASH_BASE when booting from flash.
3370 - CONFIG_SYS_MONITOR_LEN:
3371 Size of memory reserved for monitor code, used to
3372 determine _at_compile_time_ (!) if the environment is
3373 embedded within the U-Boot image, or in a separate
3376 - CONFIG_SYS_MALLOC_LEN:
3377 Size of DRAM reserved for malloc() use.
3379 - CONFIG_SYS_MALLOC_F_LEN
3380 Size of the malloc() pool for use before relocation. If
3381 this is defined, then a very simple malloc() implementation
3382 will become available before relocation. The address is just
3383 below the global data, and the stack is moved down to make
3386 This feature allocates regions with increasing addresses
3387 within the region. calloc() is supported, but realloc()
3388 is not available. free() is supported but does nothing.
3389 The memory will be freed (or in fact just forgotten) when
3390 U-Boot relocates itself.
3392 - CONFIG_SYS_MALLOC_SIMPLE
3393 Provides a simple and small malloc() and calloc() for those
3394 boards which do not use the full malloc in SPL (which is
3395 enabled with CONFIG_SYS_SPL_MALLOC_START).
3397 - CONFIG_SYS_NONCACHED_MEMORY:
3398 Size of non-cached memory area. This area of memory will be
3399 typically located right below the malloc() area and mapped
3400 uncached in the MMU. This is useful for drivers that would
3401 otherwise require a lot of explicit cache maintenance. For
3402 some drivers it's also impossible to properly maintain the
3403 cache. For example if the regions that need to be flushed
3404 are not a multiple of the cache-line size, *and* padding
3405 cannot be allocated between the regions to align them (i.e.
3406 if the HW requires a contiguous array of regions, and the
3407 size of each region is not cache-aligned), then a flush of
3408 one region may result in overwriting data that hardware has
3409 written to another region in the same cache-line. This can
3410 happen for example in network drivers where descriptors for
3411 buffers are typically smaller than the CPU cache-line (e.g.
3412 16 bytes vs. 32 or 64 bytes).
3414 Non-cached memory is only supported on 32-bit ARM at present.
3416 - CONFIG_SYS_BOOTM_LEN:
3417 Normally compressed uImages are limited to an
3418 uncompressed size of 8 MBytes. If this is not enough,
3419 you can define CONFIG_SYS_BOOTM_LEN in your board config file
3420 to adjust this setting to your needs.
3422 - CONFIG_SYS_BOOTMAPSZ:
3423 Maximum size of memory mapped by the startup code of
3424 the Linux kernel; all data that must be processed by
3425 the Linux kernel (bd_info, boot arguments, FDT blob if
3426 used) must be put below this limit, unless "bootm_low"
3427 environment variable is defined and non-zero. In such case
3428 all data for the Linux kernel must be between "bootm_low"
3429 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
3430 variable "bootm_mapsize" will override the value of
3431 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
3432 then the value in "bootm_size" will be used instead.
3434 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
3435 Enable initrd_high functionality. If defined then the
3436 initrd_high feature is enabled and the bootm ramdisk subcommand
3439 - CONFIG_SYS_BOOT_GET_CMDLINE:
3440 Enables allocating and saving kernel cmdline in space between
3441 "bootm_low" and "bootm_low" + BOOTMAPSZ.
3443 - CONFIG_SYS_BOOT_GET_KBD:
3444 Enables allocating and saving a kernel copy of the bd_info in
3445 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
3447 - CONFIG_SYS_MAX_FLASH_BANKS:
3448 Max number of Flash memory banks
3450 - CONFIG_SYS_MAX_FLASH_SECT:
3451 Max number of sectors on a Flash chip
3453 - CONFIG_SYS_FLASH_ERASE_TOUT:
3454 Timeout for Flash erase operations (in ms)
3456 - CONFIG_SYS_FLASH_WRITE_TOUT:
3457 Timeout for Flash write operations (in ms)
3459 - CONFIG_SYS_FLASH_LOCK_TOUT
3460 Timeout for Flash set sector lock bit operation (in ms)
3462 - CONFIG_SYS_FLASH_UNLOCK_TOUT
3463 Timeout for Flash clear lock bits operation (in ms)
3465 - CONFIG_SYS_FLASH_PROTECTION
3466 If defined, hardware flash sectors protection is used
3467 instead of U-Boot software protection.
3469 - CONFIG_SYS_DIRECT_FLASH_TFTP:
3471 Enable TFTP transfers directly to flash memory;
3472 without this option such a download has to be
3473 performed in two steps: (1) download to RAM, and (2)
3474 copy from RAM to flash.
3476 The two-step approach is usually more reliable, since
3477 you can check if the download worked before you erase
3478 the flash, but in some situations (when system RAM is
3479 too limited to allow for a temporary copy of the
3480 downloaded image) this option may be very useful.
3482 - CONFIG_SYS_FLASH_CFI:
3483 Define if the flash driver uses extra elements in the
3484 common flash structure for storing flash geometry.
3486 - CONFIG_FLASH_CFI_DRIVER
3487 This option also enables the building of the cfi_flash driver
3488 in the drivers directory
3490 - CONFIG_FLASH_CFI_MTD
3491 This option enables the building of the cfi_mtd driver
3492 in the drivers directory. The driver exports CFI flash
3495 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
3496 Use buffered writes to flash.
3498 - CONFIG_FLASH_SPANSION_S29WS_N
3499 s29ws-n MirrorBit flash has non-standard addresses for buffered
3502 - CONFIG_SYS_FLASH_QUIET_TEST
3503 If this option is defined, the common CFI flash doesn't
3504 print it's warning upon not recognized FLASH banks. This
3505 is useful, if some of the configured banks are only
3506 optionally available.
3508 - CONFIG_FLASH_SHOW_PROGRESS
3509 If defined (must be an integer), print out countdown
3510 digits and dots. Recommended value: 45 (9..1) for 80
3511 column displays, 15 (3..1) for 40 column displays.
3513 - CONFIG_FLASH_VERIFY
3514 If defined, the content of the flash (destination) is compared
3515 against the source after the write operation. An error message
3516 will be printed when the contents are not identical.
3517 Please note that this option is useless in nearly all cases,
3518 since such flash programming errors usually are detected earlier
3519 while unprotecting/erasing/programming. Please only enable
3520 this option if you really know what you are doing.
3522 - CONFIG_SYS_RX_ETH_BUFFER:
3523 Defines the number of Ethernet receive buffers. On some
3524 Ethernet controllers it is recommended to set this value
3525 to 8 or even higher (EEPRO100 or 405 EMAC), since all
3526 buffers can be full shortly after enabling the interface
3527 on high Ethernet traffic.
3528 Defaults to 4 if not defined.
3530 - CONFIG_ENV_MAX_ENTRIES
3532 Maximum number of entries in the hash table that is used
3533 internally to store the environment settings. The default
3534 setting is supposed to be generous and should work in most
3535 cases. This setting can be used to tune behaviour; see
3536 lib/hashtable.c for details.
3538 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3539 - CONFIG_ENV_FLAGS_LIST_STATIC
3540 Enable validation of the values given to environment variables when
3541 calling env set. Variables can be restricted to only decimal,
3542 hexadecimal, or boolean. If CONFIG_CMD_NET is also defined,
3543 the variables can also be restricted to IP address or MAC address.
3545 The format of the list is:
3546 type_attribute = [s|d|x|b|i|m]
3547 access_attribute = [a|r|o|c]
3548 attributes = type_attribute[access_attribute]
3549 entry = variable_name[:attributes]
3552 The type attributes are:
3553 s - String (default)
3556 b - Boolean ([1yYtT|0nNfF])
3560 The access attributes are:
3566 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3567 Define this to a list (string) to define the ".flags"
3568 environment variable in the default or embedded environment.
3570 - CONFIG_ENV_FLAGS_LIST_STATIC
3571 Define this to a list (string) to define validation that
3572 should be done if an entry is not found in the ".flags"
3573 environment variable. To override a setting in the static
3574 list, simply add an entry for the same variable name to the
3577 If CONFIG_REGEX is defined, the variable_name above is evaluated as a
3578 regular expression. This allows multiple variables to define the same
3579 flags without explicitly listing them for each variable.
3581 - CONFIG_ENV_ACCESS_IGNORE_FORCE
3582 If defined, don't allow the -f switch to env set override variable
3586 If stdint.h is available with your toolchain you can define this
3587 option to enable it. You can provide option 'USE_STDINT=1' when
3588 building U-Boot to enable this.
3590 The following definitions that deal with the placement and management
3591 of environment data (variable area); in general, we support the
3592 following configurations:
3594 - CONFIG_BUILD_ENVCRC:
3596 Builds up envcrc with the target environment so that external utils
3597 may easily extract it and embed it in final U-Boot images.
3599 - CONFIG_ENV_IS_IN_FLASH:
3601 Define this if the environment is in flash memory.
3603 a) The environment occupies one whole flash sector, which is
3604 "embedded" in the text segment with the U-Boot code. This
3605 happens usually with "bottom boot sector" or "top boot
3606 sector" type flash chips, which have several smaller
3607 sectors at the start or the end. For instance, such a
3608 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
3609 such a case you would place the environment in one of the
3610 4 kB sectors - with U-Boot code before and after it. With
3611 "top boot sector" type flash chips, you would put the
3612 environment in one of the last sectors, leaving a gap
3613 between U-Boot and the environment.
3615 - CONFIG_ENV_OFFSET:
3617 Offset of environment data (variable area) to the
3618 beginning of flash memory; for instance, with bottom boot
3619 type flash chips the second sector can be used: the offset
3620 for this sector is given here.
3622 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
3626 This is just another way to specify the start address of
3627 the flash sector containing the environment (instead of
3630 - CONFIG_ENV_SECT_SIZE:
3632 Size of the sector containing the environment.
3635 b) Sometimes flash chips have few, equal sized, BIG sectors.
3636 In such a case you don't want to spend a whole sector for
3641 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
3642 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
3643 of this flash sector for the environment. This saves
3644 memory for the RAM copy of the environment.
3646 It may also save flash memory if you decide to use this
3647 when your environment is "embedded" within U-Boot code,
3648 since then the remainder of the flash sector could be used
3649 for U-Boot code. It should be pointed out that this is
3650 STRONGLY DISCOURAGED from a robustness point of view:
3651 updating the environment in flash makes it always
3652 necessary to erase the WHOLE sector. If something goes
3653 wrong before the contents has been restored from a copy in
3654 RAM, your target system will be dead.
3656 - CONFIG_ENV_ADDR_REDUND
3657 CONFIG_ENV_SIZE_REDUND
3659 These settings describe a second storage area used to hold
3660 a redundant copy of the environment data, so that there is
3661 a valid backup copy in case there is a power failure during
3662 a "saveenv" operation.
3664 BE CAREFUL! Any changes to the flash layout, and some changes to the
3665 source code will make it necessary to adapt <board>/u-boot.lds*
3669 - CONFIG_ENV_IS_IN_NVRAM:
3671 Define this if you have some non-volatile memory device
3672 (NVRAM, battery buffered SRAM) which you want to use for the
3678 These two #defines are used to determine the memory area you
3679 want to use for environment. It is assumed that this memory
3680 can just be read and written to, without any special
3683 BE CAREFUL! The first access to the environment happens quite early
3684 in U-Boot initialization (when we try to get the setting of for the
3685 console baudrate). You *MUST* have mapped your NVRAM area then, or
3688 Please note that even with NVRAM we still use a copy of the
3689 environment in RAM: we could work on NVRAM directly, but we want to
3690 keep settings there always unmodified except somebody uses "saveenv"
3691 to save the current settings.
3694 - CONFIG_ENV_IS_IN_EEPROM:
3696 Use this if you have an EEPROM or similar serial access
3697 device and a driver for it.
3699 - CONFIG_ENV_OFFSET:
3702 These two #defines specify the offset and size of the
3703 environment area within the total memory of your EEPROM.
3705 - CONFIG_SYS_I2C_EEPROM_ADDR:
3706 If defined, specified the chip address of the EEPROM device.
3707 The default address is zero.
3709 - CONFIG_SYS_I2C_EEPROM_BUS:
3710 If defined, specified the i2c bus of the EEPROM device.
3712 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
3713 If defined, the number of bits used to address bytes in a
3714 single page in the EEPROM device. A 64 byte page, for example
3715 would require six bits.
3717 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
3718 If defined, the number of milliseconds to delay between
3719 page writes. The default is zero milliseconds.
3721 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
3722 The length in bytes of the EEPROM memory array address. Note
3723 that this is NOT the chip address length!
3725 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
3726 EEPROM chips that implement "address overflow" are ones
3727 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
3728 address and the extra bits end up in the "chip address" bit
3729 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
3732 Note that we consider the length of the address field to
3733 still be one byte because the extra address bits are hidden
3734 in the chip address.
3736 - CONFIG_SYS_EEPROM_SIZE:
3737 The size in bytes of the EEPROM device.
3739 - CONFIG_ENV_EEPROM_IS_ON_I2C
3740 define this, if you have I2C and SPI activated, and your
3741 EEPROM, which holds the environment, is on the I2C bus.
3743 - CONFIG_I2C_ENV_EEPROM_BUS
3744 if you have an Environment on an EEPROM reached over
3745 I2C muxes, you can define here, how to reach this
3746 EEPROM. For example:
3748 #define CONFIG_I2C_ENV_EEPROM_BUS 1
3750 EEPROM which holds the environment, is reached over
3751 a pca9547 i2c mux with address 0x70, channel 3.
3753 - CONFIG_ENV_IS_IN_DATAFLASH:
3755 Define this if you have a DataFlash memory device which you
3756 want to use for the environment.
3758 - CONFIG_ENV_OFFSET:
3762 These three #defines specify the offset and size of the
3763 environment area within the total memory of your DataFlash placed
3764 at the specified address.
3766 - CONFIG_ENV_IS_IN_SPI_FLASH:
3768 Define this if you have a SPI Flash memory device which you
3769 want to use for the environment.
3771 - CONFIG_ENV_OFFSET:
3774 These two #defines specify the offset and size of the
3775 environment area within the SPI Flash. CONFIG_ENV_OFFSET must be
3776 aligned to an erase sector boundary.
3778 - CONFIG_ENV_SECT_SIZE:
3780 Define the SPI flash's sector size.
3782 - CONFIG_ENV_OFFSET_REDUND (optional):
3784 This setting describes a second storage area of CONFIG_ENV_SIZE
3785 size used to hold a redundant copy of the environment data, so
3786 that there is a valid backup copy in case there is a power failure
3787 during a "saveenv" operation. CONFIG_ENV_OFFSET_REDUND must be
3788 aligned to an erase sector boundary.
3790 - CONFIG_ENV_SPI_BUS (optional):
3791 - CONFIG_ENV_SPI_CS (optional):
3793 Define the SPI bus and chip select. If not defined they will be 0.
3795 - CONFIG_ENV_SPI_MAX_HZ (optional):
3797 Define the SPI max work clock. If not defined then use 1MHz.
3799 - CONFIG_ENV_SPI_MODE (optional):
3801 Define the SPI work mode. If not defined then use SPI_MODE_3.
3803 - CONFIG_ENV_IS_IN_REMOTE:
3805 Define this if you have a remote memory space which you
3806 want to use for the local device's environment.
3811 These two #defines specify the address and size of the
3812 environment area within the remote memory space. The
3813 local device can get the environment from remote memory
3814 space by SRIO or PCIE links.
3816 BE CAREFUL! For some special cases, the local device can not use
3817 "saveenv" command. For example, the local device will get the
3818 environment stored in a remote NOR flash by SRIO or PCIE link,
3819 but it can not erase, write this NOR flash by SRIO or PCIE interface.
3821 - CONFIG_ENV_IS_IN_NAND:
3823 Define this if you have a NAND device which you want to use
3824 for the environment.
3826 - CONFIG_ENV_OFFSET:
3829 These two #defines specify the offset and size of the environment
3830 area within the first NAND device. CONFIG_ENV_OFFSET must be
3831 aligned to an erase block boundary.
3833 - CONFIG_ENV_OFFSET_REDUND (optional):
3835 This setting describes a second storage area of CONFIG_ENV_SIZE
3836 size used to hold a redundant copy of the environment data, so
3837 that there is a valid backup copy in case there is a power failure
3838 during a "saveenv" operation. CONFIG_ENV_OFFSET_REDUND must be
3839 aligned to an erase block boundary.
3841 - CONFIG_ENV_RANGE (optional):
3843 Specifies the length of the region in which the environment
3844 can be written. This should be a multiple of the NAND device's
3845 block size. Specifying a range with more erase blocks than
3846 are needed to hold CONFIG_ENV_SIZE allows bad blocks within
3847 the range to be avoided.
3849 - CONFIG_ENV_OFFSET_OOB (optional):
3851 Enables support for dynamically retrieving the offset of the
3852 environment from block zero's out-of-band data. The
3853 "nand env.oob" command can be used to record this offset.
3854 Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
3855 using CONFIG_ENV_OFFSET_OOB.
3857 - CONFIG_NAND_ENV_DST
3859 Defines address in RAM to which the nand_spl code should copy the
3860 environment. If redundant environment is used, it will be copied to
3861 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
3863 - CONFIG_ENV_IS_IN_UBI:
3865 Define this if you have an UBI volume that you want to use for the
3866 environment. This has the benefit of wear-leveling the environment
3867 accesses, which is important on NAND.
3869 - CONFIG_ENV_UBI_PART:
3871 Define this to a string that is the mtd partition containing the UBI.
3873 - CONFIG_ENV_UBI_VOLUME:
3875 Define this to the name of the volume that you want to store the
3878 - CONFIG_ENV_UBI_VOLUME_REDUND:
3880 Define this to the name of another volume to store a second copy of
3881 the environment in. This will enable redundant environments in UBI.
3882 It is assumed that both volumes are in the same MTD partition.
3884 - CONFIG_UBI_SILENCE_MSG
3885 - CONFIG_UBIFS_SILENCE_MSG
3887 You will probably want to define these to avoid a really noisy system
3888 when storing the env in UBI.
3890 - CONFIG_ENV_IS_IN_FAT:
3891 Define this if you want to use the FAT file system for the environment.
3893 - FAT_ENV_INTERFACE:
3895 Define this to a string that is the name of the block device.
3897 - FAT_ENV_DEVICE_AND_PART:
3899 Define this to a string to specify the partition of the device. It can
3902 "D:P", "D:0", "D", "D:" or "D:auto" (D, P are integers. And P >= 1)
3903 - "D:P": device D partition P. Error occurs if device D has no
3906 - "D" or "D:": device D partition 1 if device D has partition
3907 table, or the whole device D if has no partition
3909 - "D:auto": first partition in device D with bootable flag set.
3910 If none, first valid partition in device D. If no
3911 partition table then means device D.
3915 It's a string of the FAT file name. This file use to store the
3919 This should be defined. Otherwise it cannot save the environment file.
3921 - CONFIG_ENV_IS_IN_MMC:
3923 Define this if you have an MMC device which you want to use for the
3926 - CONFIG_SYS_MMC_ENV_DEV:
3928 Specifies which MMC device the environment is stored in.
3930 - CONFIG_SYS_MMC_ENV_PART (optional):
3932 Specifies which MMC partition the environment is stored in. If not
3933 set, defaults to partition 0, the user area. Common values might be
3934 1 (first MMC boot partition), 2 (second MMC boot partition).
3936 - CONFIG_ENV_OFFSET:
3939 These two #defines specify the offset and size of the environment
3940 area within the specified MMC device.
3942 If offset is positive (the usual case), it is treated as relative to
3943 the start of the MMC partition. If offset is negative, it is treated
3944 as relative to the end of the MMC partition. This can be useful if
3945 your board may be fitted with different MMC devices, which have
3946 different sizes for the MMC partitions, and you always want the
3947 environment placed at the very end of the partition, to leave the
3948 maximum possible space before it, to store other data.
3950 These two values are in units of bytes, but must be aligned to an
3951 MMC sector boundary.
3953 - CONFIG_ENV_OFFSET_REDUND (optional):
3955 Specifies a second storage area, of CONFIG_ENV_SIZE size, used to
3956 hold a redundant copy of the environment data. This provides a
3957 valid backup copy in case the other copy is corrupted, e.g. due
3958 to a power failure during a "saveenv" operation.
3960 This value may also be positive or negative; this is handled in the
3961 same way as CONFIG_ENV_OFFSET.
3963 This value is also in units of bytes, but must also be aligned to
3964 an MMC sector boundary.
3966 - CONFIG_ENV_SIZE_REDUND (optional):
3968 This value need not be set, even when CONFIG_ENV_OFFSET_REDUND is
3969 set. If this value is set, it must be set to the same value as
3972 - CONFIG_SYS_SPI_INIT_OFFSET
3974 Defines offset to the initial SPI buffer area in DPRAM. The
3975 area is used at an early stage (ROM part) if the environment
3976 is configured to reside in the SPI EEPROM: We need a 520 byte
3977 scratch DPRAM area. It is used between the two initialization
3978 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
3979 to be a good choice since it makes it far enough from the
3980 start of the data area as well as from the stack pointer.
3982 Please note that the environment is read-only until the monitor
3983 has been relocated to RAM and a RAM copy of the environment has been
3984 created; also, when using EEPROM you will have to use getenv_f()
3985 until then to read environment variables.
3987 The environment is protected by a CRC32 checksum. Before the monitor
3988 is relocated into RAM, as a result of a bad CRC you will be working
3989 with the compiled-in default environment - *silently*!!! [This is
3990 necessary, because the first environment variable we need is the
3991 "baudrate" setting for the console - if we have a bad CRC, we don't
3992 have any device yet where we could complain.]
3994 Note: once the monitor has been relocated, then it will complain if
3995 the default environment is used; a new CRC is computed as soon as you
3996 use the "saveenv" command to store a valid environment.
3998 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
3999 Echo the inverted Ethernet link state to the fault LED.
4001 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
4002 also needs to be defined.
4004 - CONFIG_SYS_FAULT_MII_ADDR:
4005 MII address of the PHY to check for the Ethernet link state.
4007 - CONFIG_NS16550_MIN_FUNCTIONS:
4008 Define this if you desire to only have use of the NS16550_init
4009 and NS16550_putc functions for the serial driver located at
4010 drivers/serial/ns16550.c. This option is useful for saving
4011 space for already greatly restricted images, including but not
4012 limited to NAND_SPL configurations.
4014 - CONFIG_DISPLAY_BOARDINFO
4015 Display information about the board that U-Boot is running on
4016 when U-Boot starts up. The board function checkboard() is called
4019 - CONFIG_DISPLAY_BOARDINFO_LATE
4020 Similar to the previous option, but display this information
4021 later, once stdio is running and output goes to the LCD, if
4024 - CONFIG_BOARD_SIZE_LIMIT:
4025 Maximum size of the U-Boot image. When defined, the
4026 build system checks that the actual size does not
4029 Low Level (hardware related) configuration options:
4030 ---------------------------------------------------
4032 - CONFIG_SYS_CACHELINE_SIZE:
4033 Cache Line Size of the CPU.
4035 - CONFIG_SYS_DEFAULT_IMMR:
4036 Default address of the IMMR after system reset.
4038 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
4039 and RPXsuper) to be able to adjust the position of
4040 the IMMR register after a reset.
4042 - CONFIG_SYS_CCSRBAR_DEFAULT:
4043 Default (power-on reset) physical address of CCSR on Freescale
4046 - CONFIG_SYS_CCSRBAR:
4047 Virtual address of CCSR. On a 32-bit build, this is typically
4048 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
4050 CONFIG_SYS_DEFAULT_IMMR must also be set to this value,
4051 for cross-platform code that uses that macro instead.
4053 - CONFIG_SYS_CCSRBAR_PHYS:
4054 Physical address of CCSR. CCSR can be relocated to a new
4055 physical address, if desired. In this case, this macro should
4056 be set to that address. Otherwise, it should be set to the
4057 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
4058 is typically relocated on 36-bit builds. It is recommended
4059 that this macro be defined via the _HIGH and _LOW macros:
4061 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
4062 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
4064 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
4065 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
4066 either 0 (32-bit build) or 0xF (36-bit build). This macro is
4067 used in assembly code, so it must not contain typecasts or
4068 integer size suffixes (e.g. "ULL").
4070 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
4071 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
4072 used in assembly code, so it must not contain typecasts or
4073 integer size suffixes (e.g. "ULL").
4075 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
4076 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
4077 forced to a value that ensures that CCSR is not relocated.
4079 - Floppy Disk Support:
4080 CONFIG_SYS_FDC_DRIVE_NUMBER
4082 the default drive number (default value 0)
4084 CONFIG_SYS_ISA_IO_STRIDE
4086 defines the spacing between FDC chipset registers
4089 CONFIG_SYS_ISA_IO_OFFSET
4091 defines the offset of register from address. It
4092 depends on which part of the data bus is connected to
4093 the FDC chipset. (default value 0)
4095 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
4096 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
4099 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
4100 fdc_hw_init() is called at the beginning of the FDC
4101 setup. fdc_hw_init() must be provided by the board
4102 source code. It is used to make hardware-dependent
4106 Most IDE controllers were designed to be connected with PCI
4107 interface. Only few of them were designed for AHB interface.
4108 When software is doing ATA command and data transfer to
4109 IDE devices through IDE-AHB controller, some additional
4110 registers accessing to these kind of IDE-AHB controller
4113 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
4114 DO NOT CHANGE unless you know exactly what you're
4115 doing! (11-4) [MPC8xx/82xx systems only]
4117 - CONFIG_SYS_INIT_RAM_ADDR:
4119 Start address of memory area that can be used for
4120 initial data and stack; please note that this must be
4121 writable memory that is working WITHOUT special
4122 initialization, i. e. you CANNOT use normal RAM which
4123 will become available only after programming the
4124 memory controller and running certain initialization
4127 U-Boot uses the following memory types:
4128 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
4129 - MPC824X: data cache
4130 - PPC4xx: data cache
4132 - CONFIG_SYS_GBL_DATA_OFFSET:
4134 Offset of the initial data structure in the memory
4135 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
4136 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
4137 data is located at the end of the available space
4138 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
4139 GENERATED_GBL_DATA_SIZE), and the initial stack is just
4140 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
4141 CONFIG_SYS_GBL_DATA_OFFSET) downward.
4144 On the MPC824X (or other systems that use the data
4145 cache for initial memory) the address chosen for
4146 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
4147 point to an otherwise UNUSED address space between
4148 the top of RAM and the start of the PCI space.
4150 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
4152 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
4154 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
4156 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
4158 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
4160 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
4162 - CONFIG_SYS_OR_TIMING_SDRAM:
4165 - CONFIG_SYS_MAMR_PTA:
4166 periodic timer for refresh
4168 - CONFIG_SYS_DER: Debug Event Register (37-47)
4170 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
4171 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
4172 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
4173 CONFIG_SYS_BR1_PRELIM:
4174 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
4176 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
4177 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
4178 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
4179 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
4181 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
4182 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
4183 Machine Mode Register and Memory Periodic Timer
4184 Prescaler definitions (SDRAM timing)
4186 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
4187 enable I2C microcode relocation patch (MPC8xx);
4188 define relocation offset in DPRAM [DSP2]
4190 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
4191 enable SMC microcode relocation patch (MPC8xx);
4192 define relocation offset in DPRAM [SMC1]
4194 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
4195 enable SPI microcode relocation patch (MPC8xx);
4196 define relocation offset in DPRAM [SCC4]
4198 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
4199 Offset of the bootmode word in DPRAM used by post
4200 (Power On Self Tests). This definition overrides
4201 #define'd default value in commproc.h resp.
4204 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
4205 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
4206 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
4207 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
4208 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
4209 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
4210 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
4211 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
4212 Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
4214 - CONFIG_PCI_DISABLE_PCIE:
4215 Disable PCI-Express on systems where it is supported but not
4218 - CONFIG_PCI_ENUM_ONLY
4219 Only scan through and get the devices on the buses.
4220 Don't do any setup work, presumably because someone or
4221 something has already done it, and we don't need to do it
4222 a second time. Useful for platforms that are pre-booted
4223 by coreboot or similar.
4225 - CONFIG_PCI_INDIRECT_BRIDGE:
4226 Enable support for indirect PCI bridges.
4229 Chip has SRIO or not
4232 Board has SRIO 1 port available
4235 Board has SRIO 2 port available
4237 - CONFIG_SRIO_PCIE_BOOT_MASTER
4238 Board can support master function for Boot from SRIO and PCIE
4240 - CONFIG_SYS_SRIOn_MEM_VIRT:
4241 Virtual Address of SRIO port 'n' memory region
4243 - CONFIG_SYS_SRIOn_MEM_PHYS:
4244 Physical Address of SRIO port 'n' memory region
4246 - CONFIG_SYS_SRIOn_MEM_SIZE:
4247 Size of SRIO port 'n' memory region
4249 - CONFIG_SYS_NAND_BUSWIDTH_16BIT
4250 Defined to tell the NAND controller that the NAND chip is using
4252 Not all NAND drivers use this symbol.
4253 Example of drivers that use it:
4254 - drivers/mtd/nand/ndfc.c
4255 - drivers/mtd/nand/mxc_nand.c
4257 - CONFIG_SYS_NDFC_EBC0_CFG
4258 Sets the EBC0_CFG register for the NDFC. If not defined
4259 a default value will be used.
4262 Get DDR timing information from an I2C EEPROM. Common
4263 with pluggable memory modules such as SODIMMs
4266 I2C address of the SPD EEPROM
4268 - CONFIG_SYS_SPD_BUS_NUM
4269 If SPD EEPROM is on an I2C bus other than the first
4270 one, specify here. Note that the value must resolve
4271 to something your driver can deal with.
4273 - CONFIG_SYS_DDR_RAW_TIMING
4274 Get DDR timing information from other than SPD. Common with
4275 soldered DDR chips onboard without SPD. DDR raw timing
4276 parameters are extracted from datasheet and hard-coded into
4277 header files or board specific files.
4279 - CONFIG_FSL_DDR_INTERACTIVE
4280 Enable interactive DDR debugging. See doc/README.fsl-ddr.
4282 - CONFIG_FSL_DDR_SYNC_REFRESH
4283 Enable sync of refresh for multiple controllers.
4285 - CONFIG_FSL_DDR_BIST
4286 Enable built-in memory test for Freescale DDR controllers.
4288 - CONFIG_SYS_83XX_DDR_USES_CS0
4289 Only for 83xx systems. If specified, then DDR should
4290 be configured using CS0 and CS1 instead of CS2 and CS3.
4292 - CONFIG_ETHER_ON_FEC[12]
4293 Define to enable FEC[12] on a 8xx series processor.
4295 - CONFIG_FEC[12]_PHY
4296 Define to the hardcoded PHY address which corresponds
4297 to the given FEC; i. e.
4298 #define CONFIG_FEC1_PHY 4
4299 means that the PHY with address 4 is connected to FEC1
4301 When set to -1, means to probe for first available.
4303 - CONFIG_FEC[12]_PHY_NORXERR
4304 The PHY does not have a RXERR line (RMII only).
4305 (so program the FEC to ignore it).
4308 Enable RMII mode for all FECs.
4309 Note that this is a global option, we can't
4310 have one FEC in standard MII mode and another in RMII mode.
4312 - CONFIG_CRC32_VERIFY
4313 Add a verify option to the crc32 command.
4316 => crc32 -v <address> <count> <crc32>
4318 Where address/count indicate a memory area
4319 and crc32 is the correct crc32 which the
4323 Add the "loopw" memory command. This only takes effect if
4324 the memory commands are activated globally (CONFIG_CMD_MEM).
4327 Add the "mdc" and "mwc" memory commands. These are cyclic
4332 This command will print 4 bytes (10,11,12,13) each 500 ms.
4334 => mwc.l 100 12345678 10
4335 This command will write 12345678 to address 100 all 10 ms.
4337 This only takes effect if the memory commands are activated
4338 globally (CONFIG_CMD_MEM).
4340 - CONFIG_SKIP_LOWLEVEL_INIT
4341 [ARM, NDS32, MIPS only] If this variable is defined, then certain
4342 low level initializations (like setting up the memory
4343 controller) are omitted and/or U-Boot does not
4344 relocate itself into RAM.
4346 Normally this variable MUST NOT be defined. The only
4347 exception is when U-Boot is loaded (to RAM) by some
4348 other boot loader or by a debugger which performs
4349 these initializations itself.
4351 - CONFIG_SKIP_LOWLEVEL_INIT_ONLY
4352 [ARM926EJ-S only] This allows just the call to lowlevel_init()
4353 to be skipped. The normal CP15 init (such as enabling the
4354 instruction cache) is still performed.
4357 Modifies the behaviour of start.S when compiling a loader
4358 that is executed before the actual U-Boot. E.g. when
4359 compiling a NAND SPL.
4362 Modifies the behaviour of start.S when compiling a loader
4363 that is executed after the SPL and before the actual U-Boot.
4364 It is loaded by the SPL.
4366 - CONFIG_SYS_MPC85XX_NO_RESETVEC
4367 Only for 85xx systems. If this variable is specified, the section
4368 .resetvec is not kept and the section .bootpg is placed in the
4369 previous 4k of the .text section.
4371 - CONFIG_ARCH_MAP_SYSMEM
4372 Generally U-Boot (and in particular the md command) uses
4373 effective address. It is therefore not necessary to regard
4374 U-Boot address as virtual addresses that need to be translated
4375 to physical addresses. However, sandbox requires this, since
4376 it maintains its own little RAM buffer which contains all
4377 addressable memory. This option causes some memory accesses
4378 to be mapped through map_sysmem() / unmap_sysmem().
4380 - CONFIG_X86_RESET_VECTOR
4381 If defined, the x86 reset vector code is included. This is not
4382 needed when U-Boot is running from Coreboot.
4384 - CONFIG_SPL_AM33XX_ENABLE_RTC32K_OSC:
4385 Enables the RTC32K OSC on AM33xx based plattforms
4387 - CONFIG_SYS_NAND_NO_SUBPAGE_WRITE
4388 Option to disable subpage write in NAND driver
4389 driver that uses this:
4390 drivers/mtd/nand/davinci_nand.c
4392 Freescale QE/FMAN Firmware Support:
4393 -----------------------------------
4395 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
4396 loading of "firmware", which is encoded in the QE firmware binary format.
4397 This firmware often needs to be loaded during U-Boot booting, so macros
4398 are used to identify the storage device (NOR flash, SPI, etc) and the address
4401 - CONFIG_SYS_FMAN_FW_ADDR
4402 The address in the storage device where the FMAN microcode is located. The
4403 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4406 - CONFIG_SYS_QE_FW_ADDR
4407 The address in the storage device where the QE microcode is located. The
4408 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4411 - CONFIG_SYS_QE_FMAN_FW_LENGTH
4412 The maximum possible size of the firmware. The firmware binary format
4413 has a field that specifies the actual size of the firmware, but it
4414 might not be possible to read any part of the firmware unless some
4415 local storage is allocated to hold the entire firmware first.
4417 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
4418 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
4419 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
4420 virtual address in NOR flash.
4422 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
4423 Specifies that QE/FMAN firmware is located in NAND flash.
4424 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
4426 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
4427 Specifies that QE/FMAN firmware is located on the primary SD/MMC
4428 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
4430 - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
4431 Specifies that QE/FMAN firmware is located in the remote (master)
4432 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
4433 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
4434 window->master inbound window->master LAW->the ucode address in
4435 master's memory space.
4437 Freescale Layerscape Management Complex Firmware Support:
4438 ---------------------------------------------------------
4439 The Freescale Layerscape Management Complex (MC) supports the loading of
4441 This firmware often needs to be loaded during U-Boot booting, so macros
4442 are used to identify the storage device (NOR flash, SPI, etc) and the address
4445 - CONFIG_FSL_MC_ENET
4446 Enable the MC driver for Layerscape SoCs.
4448 Freescale Layerscape Debug Server Support:
4449 -------------------------------------------
4450 The Freescale Layerscape Debug Server Support supports the loading of
4451 "Debug Server firmware" and triggering SP boot-rom.
4452 This firmware often needs to be loaded during U-Boot booting.
4454 - CONFIG_SYS_MC_RSV_MEM_ALIGN
4455 Define alignment of reserved memory MC requires
4460 In order to achieve reproducible builds, timestamps used in the U-Boot build
4461 process have to be set to a fixed value.
4463 This is done using the SOURCE_DATE_EPOCH environment variable.
4464 SOURCE_DATE_EPOCH is to be set on the build host's shell, not as a configuration
4465 option for U-Boot or an environment variable in U-Boot.
4467 SOURCE_DATE_EPOCH should be set to a number of seconds since the epoch, in UTC.
4469 Building the Software:
4470 ======================
4472 Building U-Boot has been tested in several native build environments
4473 and in many different cross environments. Of course we cannot support
4474 all possibly existing versions of cross development tools in all
4475 (potentially obsolete) versions. In case of tool chain problems we
4476 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
4477 which is extensively used to build and test U-Boot.
4479 If you are not using a native environment, it is assumed that you
4480 have GNU cross compiling tools available in your path. In this case,
4481 you must set the environment variable CROSS_COMPILE in your shell.
4482 Note that no changes to the Makefile or any other source files are
4483 necessary. For example using the ELDK on a 4xx CPU, please enter:
4485 $ CROSS_COMPILE=ppc_4xx-
4486 $ export CROSS_COMPILE
4488 Note: If you wish to generate Windows versions of the utilities in
4489 the tools directory you can use the MinGW toolchain
4490 (http://www.mingw.org). Set your HOST tools to the MinGW
4491 toolchain and execute 'make tools'. For example:
4493 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
4495 Binaries such as tools/mkimage.exe will be created which can
4496 be executed on computers running Windows.
4498 U-Boot is intended to be simple to build. After installing the
4499 sources you must configure U-Boot for one specific board type. This
4504 where "NAME_defconfig" is the name of one of the existing configu-
4505 rations; see boards.cfg for supported names.
4507 Note: for some board special configuration names may exist; check if
4508 additional information is available from the board vendor; for
4509 instance, the TQM823L systems are available without (standard)
4510 or with LCD support. You can select such additional "features"
4511 when choosing the configuration, i. e.
4513 make TQM823L_defconfig
4514 - will configure for a plain TQM823L, i. e. no LCD support
4516 make TQM823L_LCD_defconfig
4517 - will configure for a TQM823L with U-Boot console on LCD
4522 Finally, type "make all", and you should get some working U-Boot
4523 images ready for download to / installation on your system:
4525 - "u-boot.bin" is a raw binary image
4526 - "u-boot" is an image in ELF binary format
4527 - "u-boot.srec" is in Motorola S-Record format
4529 By default the build is performed locally and the objects are saved
4530 in the source directory. One of the two methods can be used to change
4531 this behavior and build U-Boot to some external directory:
4533 1. Add O= to the make command line invocations:
4535 make O=/tmp/build distclean
4536 make O=/tmp/build NAME_defconfig
4537 make O=/tmp/build all
4539 2. Set environment variable KBUILD_OUTPUT to point to the desired location:
4541 export KBUILD_OUTPUT=/tmp/build
4546 Note that the command line "O=" setting overrides the KBUILD_OUTPUT environment
4550 Please be aware that the Makefiles assume you are using GNU make, so
4551 for instance on NetBSD you might need to use "gmake" instead of
4555 If the system board that you have is not listed, then you will need
4556 to port U-Boot to your hardware platform. To do this, follow these
4559 1. Create a new directory to hold your board specific code. Add any
4560 files you need. In your board directory, you will need at least
4561 the "Makefile" and a "<board>.c".
4562 2. Create a new configuration file "include/configs/<board>.h" for
4564 3. If you're porting U-Boot to a new CPU, then also create a new
4565 directory to hold your CPU specific code. Add any files you need.
4566 4. Run "make <board>_defconfig" with your new name.
4567 5. Type "make", and you should get a working "u-boot.srec" file
4568 to be installed on your target system.
4569 6. Debug and solve any problems that might arise.
4570 [Of course, this last step is much harder than it sounds.]
4573 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
4574 ==============================================================
4576 If you have modified U-Boot sources (for instance added a new board
4577 or support for new devices, a new CPU, etc.) you are expected to
4578 provide feedback to the other developers. The feedback normally takes
4579 the form of a "patch", i. e. a context diff against a certain (latest
4580 official or latest in the git repository) version of U-Boot sources.
4582 But before you submit such a patch, please verify that your modifi-
4583 cation did not break existing code. At least make sure that *ALL* of
4584 the supported boards compile WITHOUT ANY compiler warnings. To do so,
4585 just run the buildman script (tools/buildman/buildman), which will
4586 configure and build U-Boot for ALL supported system. Be warned, this
4587 will take a while. Please see the buildman README, or run 'buildman -H'
4591 See also "U-Boot Porting Guide" below.
4594 Monitor Commands - Overview:
4595 ============================
4597 go - start application at address 'addr'
4598 run - run commands in an environment variable
4599 bootm - boot application image from memory
4600 bootp - boot image via network using BootP/TFTP protocol
4601 bootz - boot zImage from memory
4602 tftpboot- boot image via network using TFTP protocol
4603 and env variables "ipaddr" and "serverip"
4604 (and eventually "gatewayip")
4605 tftpput - upload a file via network using TFTP protocol
4606 rarpboot- boot image via network using RARP/TFTP protocol
4607 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
4608 loads - load S-Record file over serial line
4609 loadb - load binary file over serial line (kermit mode)
4611 mm - memory modify (auto-incrementing)
4612 nm - memory modify (constant address)
4613 mw - memory write (fill)
4615 cmp - memory compare
4616 crc32 - checksum calculation
4617 i2c - I2C sub-system
4618 sspi - SPI utility commands
4619 base - print or set address offset
4620 printenv- print environment variables
4621 setenv - set environment variables
4622 saveenv - save environment variables to persistent storage
4623 protect - enable or disable FLASH write protection
4624 erase - erase FLASH memory
4625 flinfo - print FLASH memory information
4626 nand - NAND memory operations (see doc/README.nand)
4627 bdinfo - print Board Info structure
4628 iminfo - print header information for application image
4629 coninfo - print console devices and informations
4630 ide - IDE sub-system
4631 loop - infinite loop on address range
4632 loopw - infinite write loop on address range
4633 mtest - simple RAM test
4634 icache - enable or disable instruction cache
4635 dcache - enable or disable data cache
4636 reset - Perform RESET of the CPU
4637 echo - echo args to console
4638 version - print monitor version
4639 help - print online help
4640 ? - alias for 'help'
4643 Monitor Commands - Detailed Description:
4644 ========================================
4648 For now: just type "help <command>".
4651 Environment Variables:
4652 ======================
4654 U-Boot supports user configuration using Environment Variables which
4655 can be made persistent by saving to Flash memory.
4657 Environment Variables are set using "setenv", printed using
4658 "printenv", and saved to Flash using "saveenv". Using "setenv"
4659 without a value can be used to delete a variable from the
4660 environment. As long as you don't save the environment you are
4661 working with an in-memory copy. In case the Flash area containing the
4662 environment is erased by accident, a default environment is provided.
4664 Some configuration options can be set using Environment Variables.
4666 List of environment variables (most likely not complete):
4668 baudrate - see CONFIG_BAUDRATE
4670 bootdelay - see CONFIG_BOOTDELAY
4672 bootcmd - see CONFIG_BOOTCOMMAND
4674 bootargs - Boot arguments when booting an RTOS image
4676 bootfile - Name of the image to load with TFTP
4678 bootm_low - Memory range available for image processing in the bootm
4679 command can be restricted. This variable is given as
4680 a hexadecimal number and defines lowest address allowed
4681 for use by the bootm command. See also "bootm_size"
4682 environment variable. Address defined by "bootm_low" is
4683 also the base of the initial memory mapping for the Linux
4684 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
4687 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
4688 This variable is given as a hexadecimal number and it
4689 defines the size of the memory region starting at base
4690 address bootm_low that is accessible by the Linux kernel
4691 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
4692 as the default value if it is defined, and bootm_size is
4695 bootm_size - Memory range available for image processing in the bootm
4696 command can be restricted. This variable is given as
4697 a hexadecimal number and defines the size of the region
4698 allowed for use by the bootm command. See also "bootm_low"
4699 environment variable.
4701 updatefile - Location of the software update file on a TFTP server, used
4702 by the automatic software update feature. Please refer to
4703 documentation in doc/README.update for more details.
4705 autoload - if set to "no" (any string beginning with 'n'),
4706 "bootp" will just load perform a lookup of the
4707 configuration from the BOOTP server, but not try to
4708 load any image using TFTP
4710 autostart - if set to "yes", an image loaded using the "bootp",
4711 "rarpboot", "tftpboot" or "diskboot" commands will
4712 be automatically started (by internally calling
4715 If set to "no", a standalone image passed to the
4716 "bootm" command will be copied to the load address
4717 (and eventually uncompressed), but NOT be started.
4718 This can be used to load and uncompress arbitrary
4721 fdt_high - if set this restricts the maximum address that the
4722 flattened device tree will be copied into upon boot.
4723 For example, if you have a system with 1 GB memory
4724 at physical address 0x10000000, while Linux kernel
4725 only recognizes the first 704 MB as low memory, you
4726 may need to set fdt_high as 0x3C000000 to have the
4727 device tree blob be copied to the maximum address
4728 of the 704 MB low memory, so that Linux kernel can
4729 access it during the boot procedure.
4731 If this is set to the special value 0xFFFFFFFF then
4732 the fdt will not be copied at all on boot. For this
4733 to work it must reside in writable memory, have
4734 sufficient padding on the end of it for u-boot to
4735 add the information it needs into it, and the memory
4736 must be accessible by the kernel.
4738 fdtcontroladdr- if set this is the address of the control flattened
4739 device tree used by U-Boot when CONFIG_OF_CONTROL is
4742 i2cfast - (PPC405GP|PPC405EP only)
4743 if set to 'y' configures Linux I2C driver for fast
4744 mode (400kHZ). This environment variable is used in
4745 initialization code. So, for changes to be effective
4746 it must be saved and board must be reset.
4748 initrd_high - restrict positioning of initrd images:
4749 If this variable is not set, initrd images will be
4750 copied to the highest possible address in RAM; this
4751 is usually what you want since it allows for
4752 maximum initrd size. If for some reason you want to
4753 make sure that the initrd image is loaded below the
4754 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
4755 variable to a value of "no" or "off" or "0".
4756 Alternatively, you can set it to a maximum upper
4757 address to use (U-Boot will still check that it
4758 does not overwrite the U-Boot stack and data).
4760 For instance, when you have a system with 16 MB
4761 RAM, and want to reserve 4 MB from use by Linux,
4762 you can do this by adding "mem=12M" to the value of
4763 the "bootargs" variable. However, now you must make
4764 sure that the initrd image is placed in the first
4765 12 MB as well - this can be done with
4767 setenv initrd_high 00c00000
4769 If you set initrd_high to 0xFFFFFFFF, this is an
4770 indication to U-Boot that all addresses are legal
4771 for the Linux kernel, including addresses in flash
4772 memory. In this case U-Boot will NOT COPY the
4773 ramdisk at all. This may be useful to reduce the
4774 boot time on your system, but requires that this
4775 feature is supported by your Linux kernel.
4777 ipaddr - IP address; needed for tftpboot command
4779 loadaddr - Default load address for commands like "bootp",
4780 "rarpboot", "tftpboot", "loadb" or "diskboot"
4782 loads_echo - see CONFIG_LOADS_ECHO
4784 serverip - TFTP server IP address; needed for tftpboot command
4786 bootretry - see CONFIG_BOOT_RETRY_TIME
4788 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
4790 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
4792 ethprime - controls which interface is used first.
4794 ethact - controls which interface is currently active.
4795 For example you can do the following
4797 => setenv ethact FEC
4798 => ping 192.168.0.1 # traffic sent on FEC
4799 => setenv ethact SCC
4800 => ping 10.0.0.1 # traffic sent on SCC
4802 ethrotate - When set to "no" U-Boot does not go through all
4803 available network interfaces.
4804 It just stays at the currently selected interface.
4806 netretry - When set to "no" each network operation will
4807 either succeed or fail without retrying.
4808 When set to "once" the network operation will
4809 fail when all the available network interfaces
4810 are tried once without success.
4811 Useful on scripts which control the retry operation
4814 npe_ucode - set load address for the NPE microcode
4816 silent_linux - If set then Linux will be told to boot silently, by
4817 changing the console to be empty. If "yes" it will be
4818 made silent. If "no" it will not be made silent. If
4819 unset, then it will be made silent if the U-Boot console
4822 tftpsrcp - If this is set, the value is used for TFTP's
4825 tftpdstp - If this is set, the value is used for TFTP's UDP
4826 destination port instead of the Well Know Port 69.
4828 tftpblocksize - Block size to use for TFTP transfers; if not set,
4829 we use the TFTP server's default block size
4831 tftptimeout - Retransmission timeout for TFTP packets (in milli-
4832 seconds, minimum value is 1000 = 1 second). Defines
4833 when a packet is considered to be lost so it has to
4834 be retransmitted. The default is 5000 = 5 seconds.
4835 Lowering this value may make downloads succeed
4836 faster in networks with high packet loss rates or
4837 with unreliable TFTP servers.
4839 tftptimeoutcountmax - maximum count of TFTP timeouts (no
4840 unit, minimum value = 0). Defines how many timeouts
4841 can happen during a single file transfer before that
4842 transfer is aborted. The default is 10, and 0 means
4843 'no timeouts allowed'. Increasing this value may help
4844 downloads succeed with high packet loss rates, or with
4845 unreliable TFTP servers or client hardware.
4847 vlan - When set to a value < 4095 the traffic over
4848 Ethernet is encapsulated/received over 802.1q
4851 bootpretryperiod - Period during which BOOTP/DHCP sends retries.
4852 Unsigned value, in milliseconds. If not set, the period will
4853 be either the default (28000), or a value based on
4854 CONFIG_NET_RETRY_COUNT, if defined. This value has
4855 precedence over the valu based on CONFIG_NET_RETRY_COUNT.
4857 The following image location variables contain the location of images
4858 used in booting. The "Image" column gives the role of the image and is
4859 not an environment variable name. The other columns are environment
4860 variable names. "File Name" gives the name of the file on a TFTP
4861 server, "RAM Address" gives the location in RAM the image will be
4862 loaded to, and "Flash Location" gives the image's address in NOR
4863 flash or offset in NAND flash.
4865 *Note* - these variables don't have to be defined for all boards, some
4866 boards currently use other variables for these purposes, and some
4867 boards use these variables for other purposes.
4869 Image File Name RAM Address Flash Location
4870 ----- --------- ----------- --------------
4871 u-boot u-boot u-boot_addr_r u-boot_addr
4872 Linux kernel bootfile kernel_addr_r kernel_addr
4873 device tree blob fdtfile fdt_addr_r fdt_addr
4874 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
4876 The following environment variables may be used and automatically
4877 updated by the network boot commands ("bootp" and "rarpboot"),
4878 depending the information provided by your boot server:
4880 bootfile - see above
4881 dnsip - IP address of your Domain Name Server
4882 dnsip2 - IP address of your secondary Domain Name Server
4883 gatewayip - IP address of the Gateway (Router) to use
4884 hostname - Target hostname
4886 netmask - Subnet Mask
4887 rootpath - Pathname of the root filesystem on the NFS server
4888 serverip - see above
4891 There are two special Environment Variables:
4893 serial# - contains hardware identification information such
4894 as type string and/or serial number
4895 ethaddr - Ethernet address
4897 These variables can be set only once (usually during manufacturing of
4898 the board). U-Boot refuses to delete or overwrite these variables
4899 once they have been set once.
4902 Further special Environment Variables:
4904 ver - Contains the U-Boot version string as printed
4905 with the "version" command. This variable is
4906 readonly (see CONFIG_VERSION_VARIABLE).
4909 Please note that changes to some configuration parameters may take
4910 only effect after the next boot (yes, that's just like Windoze :-).
4913 Callback functions for environment variables:
4914 ---------------------------------------------
4916 For some environment variables, the behavior of u-boot needs to change
4917 when their values are changed. This functionality allows functions to
4918 be associated with arbitrary variables. On creation, overwrite, or
4919 deletion, the callback will provide the opportunity for some side
4920 effect to happen or for the change to be rejected.
4922 The callbacks are named and associated with a function using the
4923 U_BOOT_ENV_CALLBACK macro in your board or driver code.
4925 These callbacks are associated with variables in one of two ways. The
4926 static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC
4927 in the board configuration to a string that defines a list of
4928 associations. The list must be in the following format:
4930 entry = variable_name[:callback_name]
4933 If the callback name is not specified, then the callback is deleted.
4934 Spaces are also allowed anywhere in the list.
4936 Callbacks can also be associated by defining the ".callbacks" variable
4937 with the same list format above. Any association in ".callbacks" will
4938 override any association in the static list. You can define
4939 CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the
4940 ".callbacks" environment variable in the default or embedded environment.
4942 If CONFIG_REGEX is defined, the variable_name above is evaluated as a
4943 regular expression. This allows multiple variables to be connected to
4944 the same callback without explicitly listing them all out.
4947 Command Line Parsing:
4948 =====================
4950 There are two different command line parsers available with U-Boot:
4951 the old "simple" one, and the much more powerful "hush" shell:
4953 Old, simple command line parser:
4954 --------------------------------
4956 - supports environment variables (through setenv / saveenv commands)
4957 - several commands on one line, separated by ';'
4958 - variable substitution using "... ${name} ..." syntax
4959 - special characters ('$', ';') can be escaped by prefixing with '\',
4961 setenv bootcmd bootm \${address}
4962 - You can also escape text by enclosing in single apostrophes, for example:
4963 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
4968 - similar to Bourne shell, with control structures like
4969 if...then...else...fi, for...do...done; while...do...done,
4970 until...do...done, ...
4971 - supports environment ("global") variables (through setenv / saveenv
4972 commands) and local shell variables (through standard shell syntax
4973 "name=value"); only environment variables can be used with "run"
4979 (1) If a command line (or an environment variable executed by a "run"
4980 command) contains several commands separated by semicolon, and
4981 one of these commands fails, then the remaining commands will be
4984 (2) If you execute several variables with one call to run (i. e.
4985 calling run with a list of variables as arguments), any failing
4986 command will cause "run" to terminate, i. e. the remaining
4987 variables are not executed.
4989 Note for Redundant Ethernet Interfaces:
4990 =======================================
4992 Some boards come with redundant Ethernet interfaces; U-Boot supports
4993 such configurations and is capable of automatic selection of a
4994 "working" interface when needed. MAC assignment works as follows:
4996 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
4997 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
4998 "eth1addr" (=>eth1), "eth2addr", ...
5000 If the network interface stores some valid MAC address (for instance
5001 in SROM), this is used as default address if there is NO correspon-
5002 ding setting in the environment; if the corresponding environment
5003 variable is set, this overrides the settings in the card; that means:
5005 o If the SROM has a valid MAC address, and there is no address in the
5006 environment, the SROM's address is used.
5008 o If there is no valid address in the SROM, and a definition in the
5009 environment exists, then the value from the environment variable is
5012 o If both the SROM and the environment contain a MAC address, and
5013 both addresses are the same, this MAC address is used.
5015 o If both the SROM and the environment contain a MAC address, and the
5016 addresses differ, the value from the environment is used and a
5019 o If neither SROM nor the environment contain a MAC address, an error
5020 is raised. If CONFIG_NET_RANDOM_ETHADDR is defined, then in this case
5021 a random, locally-assigned MAC is used.
5023 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
5024 will be programmed into hardware as part of the initialization process. This
5025 may be skipped by setting the appropriate 'ethmacskip' environment variable.
5026 The naming convention is as follows:
5027 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
5032 U-Boot is capable of booting (and performing other auxiliary operations on)
5033 images in two formats:
5035 New uImage format (FIT)
5036 -----------------------
5038 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
5039 to Flattened Device Tree). It allows the use of images with multiple
5040 components (several kernels, ramdisks, etc.), with contents protected by
5041 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
5047 Old image format is based on binary files which can be basically anything,
5048 preceded by a special header; see the definitions in include/image.h for
5049 details; basically, the header defines the following image properties:
5051 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
5052 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
5053 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
5054 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
5056 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
5057 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
5058 Currently supported: ARM, AVR32, Intel x86, MIPS, NDS32, Nios II, PowerPC).
5059 * Compression Type (uncompressed, gzip, bzip2)
5065 The header is marked by a special Magic Number, and both the header
5066 and the data portions of the image are secured against corruption by
5073 Although U-Boot should support any OS or standalone application
5074 easily, the main focus has always been on Linux during the design of
5077 U-Boot includes many features that so far have been part of some
5078 special "boot loader" code within the Linux kernel. Also, any
5079 "initrd" images to be used are no longer part of one big Linux image;
5080 instead, kernel and "initrd" are separate images. This implementation
5081 serves several purposes:
5083 - the same features can be used for other OS or standalone
5084 applications (for instance: using compressed images to reduce the
5085 Flash memory footprint)
5087 - it becomes much easier to port new Linux kernel versions because
5088 lots of low-level, hardware dependent stuff are done by U-Boot
5090 - the same Linux kernel image can now be used with different "initrd"
5091 images; of course this also means that different kernel images can
5092 be run with the same "initrd". This makes testing easier (you don't
5093 have to build a new "zImage.initrd" Linux image when you just
5094 change a file in your "initrd"). Also, a field-upgrade of the
5095 software is easier now.
5101 Porting Linux to U-Boot based systems:
5102 ---------------------------------------
5104 U-Boot cannot save you from doing all the necessary modifications to
5105 configure the Linux device drivers for use with your target hardware
5106 (no, we don't intend to provide a full virtual machine interface to
5109 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
5111 Just make sure your machine specific header file (for instance
5112 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
5113 Information structure as we define in include/asm-<arch>/u-boot.h,
5114 and make sure that your definition of IMAP_ADDR uses the same value
5115 as your U-Boot configuration in CONFIG_SYS_IMMR.
5117 Note that U-Boot now has a driver model, a unified model for drivers.
5118 If you are adding a new driver, plumb it into driver model. If there
5119 is no uclass available, you are encouraged to create one. See
5123 Configuring the Linux kernel:
5124 -----------------------------
5126 No specific requirements for U-Boot. Make sure you have some root
5127 device (initial ramdisk, NFS) for your target system.
5130 Building a Linux Image:
5131 -----------------------
5133 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
5134 not used. If you use recent kernel source, a new build target
5135 "uImage" will exist which automatically builds an image usable by
5136 U-Boot. Most older kernels also have support for a "pImage" target,
5137 which was introduced for our predecessor project PPCBoot and uses a
5138 100% compatible format.
5142 make TQM850L_defconfig
5147 The "uImage" build target uses a special tool (in 'tools/mkimage') to
5148 encapsulate a compressed Linux kernel image with header information,
5149 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
5151 * build a standard "vmlinux" kernel image (in ELF binary format):
5153 * convert the kernel into a raw binary image:
5155 ${CROSS_COMPILE}-objcopy -O binary \
5156 -R .note -R .comment \
5157 -S vmlinux linux.bin
5159 * compress the binary image:
5163 * package compressed binary image for U-Boot:
5165 mkimage -A ppc -O linux -T kernel -C gzip \
5166 -a 0 -e 0 -n "Linux Kernel Image" \
5167 -d linux.bin.gz uImage
5170 The "mkimage" tool can also be used to create ramdisk images for use
5171 with U-Boot, either separated from the Linux kernel image, or
5172 combined into one file. "mkimage" encapsulates the images with a 64
5173 byte header containing information about target architecture,
5174 operating system, image type, compression method, entry points, time
5175 stamp, CRC32 checksums, etc.
5177 "mkimage" can be called in two ways: to verify existing images and
5178 print the header information, or to build new images.
5180 In the first form (with "-l" option) mkimage lists the information
5181 contained in the header of an existing U-Boot image; this includes
5182 checksum verification:
5184 tools/mkimage -l image
5185 -l ==> list image header information
5187 The second form (with "-d" option) is used to build a U-Boot image
5188 from a "data file" which is used as image payload:
5190 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
5191 -n name -d data_file image
5192 -A ==> set architecture to 'arch'
5193 -O ==> set operating system to 'os'
5194 -T ==> set image type to 'type'
5195 -C ==> set compression type 'comp'
5196 -a ==> set load address to 'addr' (hex)
5197 -e ==> set entry point to 'ep' (hex)
5198 -n ==> set image name to 'name'
5199 -d ==> use image data from 'datafile'
5201 Right now, all Linux kernels for PowerPC systems use the same load
5202 address (0x00000000), but the entry point address depends on the
5205 - 2.2.x kernels have the entry point at 0x0000000C,
5206 - 2.3.x and later kernels have the entry point at 0x00000000.
5208 So a typical call to build a U-Boot image would read:
5210 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5211 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
5212 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
5213 > examples/uImage.TQM850L
5214 Image Name: 2.4.4 kernel for TQM850L
5215 Created: Wed Jul 19 02:34:59 2000
5216 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5217 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5218 Load Address: 0x00000000
5219 Entry Point: 0x00000000
5221 To verify the contents of the image (or check for corruption):
5223 -> tools/mkimage -l examples/uImage.TQM850L
5224 Image Name: 2.4.4 kernel for TQM850L
5225 Created: Wed Jul 19 02:34:59 2000
5226 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5227 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5228 Load Address: 0x00000000
5229 Entry Point: 0x00000000
5231 NOTE: for embedded systems where boot time is critical you can trade
5232 speed for memory and install an UNCOMPRESSED image instead: this
5233 needs more space in Flash, but boots much faster since it does not
5234 need to be uncompressed:
5236 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
5237 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5238 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
5239 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
5240 > examples/uImage.TQM850L-uncompressed
5241 Image Name: 2.4.4 kernel for TQM850L
5242 Created: Wed Jul 19 02:34:59 2000
5243 Image Type: PowerPC Linux Kernel Image (uncompressed)
5244 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
5245 Load Address: 0x00000000
5246 Entry Point: 0x00000000
5249 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
5250 when your kernel is intended to use an initial ramdisk:
5252 -> tools/mkimage -n 'Simple Ramdisk Image' \
5253 > -A ppc -O linux -T ramdisk -C gzip \
5254 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
5255 Image Name: Simple Ramdisk Image
5256 Created: Wed Jan 12 14:01:50 2000
5257 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5258 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
5259 Load Address: 0x00000000
5260 Entry Point: 0x00000000
5262 The "dumpimage" is a tool to disassemble images built by mkimage. Its "-i"
5263 option performs the converse operation of the mkimage's second form (the "-d"
5264 option). Given an image built by mkimage, the dumpimage extracts a "data file"
5267 tools/dumpimage -i image -T type -p position data_file
5268 -i ==> extract from the 'image' a specific 'data_file'
5269 -T ==> set image type to 'type'
5270 -p ==> 'position' (starting at 0) of the 'data_file' inside the 'image'
5273 Installing a Linux Image:
5274 -------------------------
5276 To downloading a U-Boot image over the serial (console) interface,
5277 you must convert the image to S-Record format:
5279 objcopy -I binary -O srec examples/image examples/image.srec
5281 The 'objcopy' does not understand the information in the U-Boot
5282 image header, so the resulting S-Record file will be relative to
5283 address 0x00000000. To load it to a given address, you need to
5284 specify the target address as 'offset' parameter with the 'loads'
5287 Example: install the image to address 0x40100000 (which on the
5288 TQM8xxL is in the first Flash bank):
5290 => erase 40100000 401FFFFF
5296 ## Ready for S-Record download ...
5297 ~>examples/image.srec
5298 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
5300 15989 15990 15991 15992
5301 [file transfer complete]
5303 ## Start Addr = 0x00000000
5306 You can check the success of the download using the 'iminfo' command;
5307 this includes a checksum verification so you can be sure no data
5308 corruption happened:
5312 ## Checking Image at 40100000 ...
5313 Image Name: 2.2.13 for initrd on TQM850L
5314 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5315 Data Size: 335725 Bytes = 327 kB = 0 MB
5316 Load Address: 00000000
5317 Entry Point: 0000000c
5318 Verifying Checksum ... OK
5324 The "bootm" command is used to boot an application that is stored in
5325 memory (RAM or Flash). In case of a Linux kernel image, the contents
5326 of the "bootargs" environment variable is passed to the kernel as
5327 parameters. You can check and modify this variable using the
5328 "printenv" and "setenv" commands:
5331 => printenv bootargs
5332 bootargs=root=/dev/ram
5334 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5336 => printenv bootargs
5337 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5340 ## Booting Linux kernel at 40020000 ...
5341 Image Name: 2.2.13 for NFS on TQM850L
5342 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5343 Data Size: 381681 Bytes = 372 kB = 0 MB
5344 Load Address: 00000000
5345 Entry Point: 0000000c
5346 Verifying Checksum ... OK
5347 Uncompressing Kernel Image ... OK
5348 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
5349 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5350 time_init: decrementer frequency = 187500000/60
5351 Calibrating delay loop... 49.77 BogoMIPS
5352 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
5355 If you want to boot a Linux kernel with initial RAM disk, you pass
5356 the memory addresses of both the kernel and the initrd image (PPBCOOT
5357 format!) to the "bootm" command:
5359 => imi 40100000 40200000
5361 ## Checking Image at 40100000 ...
5362 Image Name: 2.2.13 for initrd on TQM850L
5363 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5364 Data Size: 335725 Bytes = 327 kB = 0 MB
5365 Load Address: 00000000
5366 Entry Point: 0000000c
5367 Verifying Checksum ... OK
5369 ## Checking Image at 40200000 ...
5370 Image Name: Simple Ramdisk Image
5371 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5372 Data Size: 566530 Bytes = 553 kB = 0 MB
5373 Load Address: 00000000
5374 Entry Point: 00000000
5375 Verifying Checksum ... OK
5377 => bootm 40100000 40200000
5378 ## Booting Linux kernel at 40100000 ...
5379 Image Name: 2.2.13 for initrd on TQM850L
5380 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5381 Data Size: 335725 Bytes = 327 kB = 0 MB
5382 Load Address: 00000000
5383 Entry Point: 0000000c
5384 Verifying Checksum ... OK
5385 Uncompressing Kernel Image ... OK
5386 ## Loading RAMDisk Image at 40200000 ...
5387 Image Name: Simple Ramdisk Image
5388 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5389 Data Size: 566530 Bytes = 553 kB = 0 MB
5390 Load Address: 00000000
5391 Entry Point: 00000000
5392 Verifying Checksum ... OK
5393 Loading Ramdisk ... OK
5394 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
5395 Boot arguments: root=/dev/ram
5396 time_init: decrementer frequency = 187500000/60
5397 Calibrating delay loop... 49.77 BogoMIPS
5399 RAMDISK: Compressed image found at block 0
5400 VFS: Mounted root (ext2 filesystem).
5404 Boot Linux and pass a flat device tree:
5407 First, U-Boot must be compiled with the appropriate defines. See the section
5408 titled "Linux Kernel Interface" above for a more in depth explanation. The
5409 following is an example of how to start a kernel and pass an updated
5415 oft=oftrees/mpc8540ads.dtb
5416 => tftp $oftaddr $oft
5417 Speed: 1000, full duplex
5419 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
5420 Filename 'oftrees/mpc8540ads.dtb'.
5421 Load address: 0x300000
5424 Bytes transferred = 4106 (100a hex)
5425 => tftp $loadaddr $bootfile
5426 Speed: 1000, full duplex
5428 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
5430 Load address: 0x200000
5431 Loading:############
5433 Bytes transferred = 1029407 (fb51f hex)
5438 => bootm $loadaddr - $oftaddr
5439 ## Booting image at 00200000 ...
5440 Image Name: Linux-2.6.17-dirty
5441 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5442 Data Size: 1029343 Bytes = 1005.2 kB
5443 Load Address: 00000000
5444 Entry Point: 00000000
5445 Verifying Checksum ... OK
5446 Uncompressing Kernel Image ... OK
5447 Booting using flat device tree at 0x300000
5448 Using MPC85xx ADS machine description
5449 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
5453 More About U-Boot Image Types:
5454 ------------------------------
5456 U-Boot supports the following image types:
5458 "Standalone Programs" are directly runnable in the environment
5459 provided by U-Boot; it is expected that (if they behave
5460 well) you can continue to work in U-Boot after return from
5461 the Standalone Program.
5462 "OS Kernel Images" are usually images of some Embedded OS which
5463 will take over control completely. Usually these programs
5464 will install their own set of exception handlers, device
5465 drivers, set up the MMU, etc. - this means, that you cannot
5466 expect to re-enter U-Boot except by resetting the CPU.
5467 "RAMDisk Images" are more or less just data blocks, and their
5468 parameters (address, size) are passed to an OS kernel that is
5470 "Multi-File Images" contain several images, typically an OS
5471 (Linux) kernel image and one or more data images like
5472 RAMDisks. This construct is useful for instance when you want
5473 to boot over the network using BOOTP etc., where the boot
5474 server provides just a single image file, but you want to get
5475 for instance an OS kernel and a RAMDisk image.
5477 "Multi-File Images" start with a list of image sizes, each
5478 image size (in bytes) specified by an "uint32_t" in network
5479 byte order. This list is terminated by an "(uint32_t)0".
5480 Immediately after the terminating 0 follow the images, one by
5481 one, all aligned on "uint32_t" boundaries (size rounded up to
5482 a multiple of 4 bytes).
5484 "Firmware Images" are binary images containing firmware (like
5485 U-Boot or FPGA images) which usually will be programmed to
5488 "Script files" are command sequences that will be executed by
5489 U-Boot's command interpreter; this feature is especially
5490 useful when you configure U-Boot to use a real shell (hush)
5491 as command interpreter.
5493 Booting the Linux zImage:
5494 -------------------------
5496 On some platforms, it's possible to boot Linux zImage. This is done
5497 using the "bootz" command. The syntax of "bootz" command is the same
5498 as the syntax of "bootm" command.
5500 Note, defining the CONFIG_SUPPORT_RAW_INITRD allows user to supply
5501 kernel with raw initrd images. The syntax is slightly different, the
5502 address of the initrd must be augmented by it's size, in the following
5503 format: "<initrd addres>:<initrd size>".
5509 One of the features of U-Boot is that you can dynamically load and
5510 run "standalone" applications, which can use some resources of
5511 U-Boot like console I/O functions or interrupt services.
5513 Two simple examples are included with the sources:
5518 'examples/hello_world.c' contains a small "Hello World" Demo
5519 application; it is automatically compiled when you build U-Boot.
5520 It's configured to run at address 0x00040004, so you can play with it
5524 ## Ready for S-Record download ...
5525 ~>examples/hello_world.srec
5526 1 2 3 4 5 6 7 8 9 10 11 ...
5527 [file transfer complete]
5529 ## Start Addr = 0x00040004
5531 => go 40004 Hello World! This is a test.
5532 ## Starting application at 0x00040004 ...
5543 Hit any key to exit ...
5545 ## Application terminated, rc = 0x0
5547 Another example, which demonstrates how to register a CPM interrupt
5548 handler with the U-Boot code, can be found in 'examples/timer.c'.
5549 Here, a CPM timer is set up to generate an interrupt every second.
5550 The interrupt service routine is trivial, just printing a '.'
5551 character, but this is just a demo program. The application can be
5552 controlled by the following keys:
5554 ? - print current values og the CPM Timer registers
5555 b - enable interrupts and start timer
5556 e - stop timer and disable interrupts
5557 q - quit application
5560 ## Ready for S-Record download ...
5561 ~>examples/timer.srec
5562 1 2 3 4 5 6 7 8 9 10 11 ...
5563 [file transfer complete]
5565 ## Start Addr = 0x00040004
5568 ## Starting application at 0x00040004 ...
5571 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
5574 [q, b, e, ?] Set interval 1000000 us
5577 [q, b, e, ?] ........
5578 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
5581 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
5584 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
5587 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
5589 [q, b, e, ?] ...Stopping timer
5591 [q, b, e, ?] ## Application terminated, rc = 0x0
5597 Over time, many people have reported problems when trying to use the
5598 "minicom" terminal emulation program for serial download. I (wd)
5599 consider minicom to be broken, and recommend not to use it. Under
5600 Unix, I recommend to use C-Kermit for general purpose use (and
5601 especially for kermit binary protocol download ("loadb" command), and
5602 use "cu" for S-Record download ("loads" command). See
5603 http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
5604 for help with kermit.
5607 Nevertheless, if you absolutely want to use it try adding this
5608 configuration to your "File transfer protocols" section:
5610 Name Program Name U/D FullScr IO-Red. Multi
5611 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
5612 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
5618 Starting at version 0.9.2, U-Boot supports NetBSD both as host
5619 (build U-Boot) and target system (boots NetBSD/mpc8xx).
5621 Building requires a cross environment; it is known to work on
5622 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
5623 need gmake since the Makefiles are not compatible with BSD make).
5624 Note that the cross-powerpc package does not install include files;
5625 attempting to build U-Boot will fail because <machine/ansi.h> is
5626 missing. This file has to be installed and patched manually:
5628 # cd /usr/pkg/cross/powerpc-netbsd/include
5630 # ln -s powerpc machine
5631 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
5632 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
5634 Native builds *don't* work due to incompatibilities between native
5635 and U-Boot include files.
5637 Booting assumes that (the first part of) the image booted is a
5638 stage-2 loader which in turn loads and then invokes the kernel
5639 proper. Loader sources will eventually appear in the NetBSD source
5640 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
5641 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
5644 Implementation Internals:
5645 =========================
5647 The following is not intended to be a complete description of every
5648 implementation detail. However, it should help to understand the
5649 inner workings of U-Boot and make it easier to port it to custom
5653 Initial Stack, Global Data:
5654 ---------------------------
5656 The implementation of U-Boot is complicated by the fact that U-Boot
5657 starts running out of ROM (flash memory), usually without access to
5658 system RAM (because the memory controller is not initialized yet).
5659 This means that we don't have writable Data or BSS segments, and BSS
5660 is not initialized as zero. To be able to get a C environment working
5661 at all, we have to allocate at least a minimal stack. Implementation
5662 options for this are defined and restricted by the CPU used: Some CPU
5663 models provide on-chip memory (like the IMMR area on MPC8xx and
5664 MPC826x processors), on others (parts of) the data cache can be
5665 locked as (mis-) used as memory, etc.
5667 Chris Hallinan posted a good summary of these issues to the
5668 U-Boot mailing list:
5670 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
5671 From: "Chris Hallinan" <clh@net1plus.com>
5672 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
5675 Correct me if I'm wrong, folks, but the way I understand it
5676 is this: Using DCACHE as initial RAM for Stack, etc, does not
5677 require any physical RAM backing up the cache. The cleverness
5678 is that the cache is being used as a temporary supply of
5679 necessary storage before the SDRAM controller is setup. It's
5680 beyond the scope of this list to explain the details, but you
5681 can see how this works by studying the cache architecture and
5682 operation in the architecture and processor-specific manuals.
5684 OCM is On Chip Memory, which I believe the 405GP has 4K. It
5685 is another option for the system designer to use as an
5686 initial stack/RAM area prior to SDRAM being available. Either
5687 option should work for you. Using CS 4 should be fine if your
5688 board designers haven't used it for something that would
5689 cause you grief during the initial boot! It is frequently not
5692 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
5693 with your processor/board/system design. The default value
5694 you will find in any recent u-boot distribution in
5695 walnut.h should work for you. I'd set it to a value larger
5696 than your SDRAM module. If you have a 64MB SDRAM module, set
5697 it above 400_0000. Just make sure your board has no resources
5698 that are supposed to respond to that address! That code in
5699 start.S has been around a while and should work as is when
5700 you get the config right.
5705 It is essential to remember this, since it has some impact on the C
5706 code for the initialization procedures:
5708 * Initialized global data (data segment) is read-only. Do not attempt
5711 * Do not use any uninitialized global data (or implicitly initialized
5712 as zero data - BSS segment) at all - this is undefined, initiali-
5713 zation is performed later (when relocating to RAM).
5715 * Stack space is very limited. Avoid big data buffers or things like
5718 Having only the stack as writable memory limits means we cannot use
5719 normal global data to share information between the code. But it
5720 turned out that the implementation of U-Boot can be greatly
5721 simplified by making a global data structure (gd_t) available to all
5722 functions. We could pass a pointer to this data as argument to _all_
5723 functions, but this would bloat the code. Instead we use a feature of
5724 the GCC compiler (Global Register Variables) to share the data: we
5725 place a pointer (gd) to the global data into a register which we
5726 reserve for this purpose.
5728 When choosing a register for such a purpose we are restricted by the
5729 relevant (E)ABI specifications for the current architecture, and by
5730 GCC's implementation.
5732 For PowerPC, the following registers have specific use:
5734 R2: reserved for system use
5735 R3-R4: parameter passing and return values
5736 R5-R10: parameter passing
5737 R13: small data area pointer
5741 (U-Boot also uses R12 as internal GOT pointer. r12
5742 is a volatile register so r12 needs to be reset when
5743 going back and forth between asm and C)
5745 ==> U-Boot will use R2 to hold a pointer to the global data
5747 Note: on PPC, we could use a static initializer (since the
5748 address of the global data structure is known at compile time),
5749 but it turned out that reserving a register results in somewhat
5750 smaller code - although the code savings are not that big (on
5751 average for all boards 752 bytes for the whole U-Boot image,
5752 624 text + 127 data).
5754 On ARM, the following registers are used:
5756 R0: function argument word/integer result
5757 R1-R3: function argument word
5758 R9: platform specific
5759 R10: stack limit (used only if stack checking is enabled)
5760 R11: argument (frame) pointer
5761 R12: temporary workspace
5764 R15: program counter
5766 ==> U-Boot will use R9 to hold a pointer to the global data
5768 Note: on ARM, only R_ARM_RELATIVE relocations are supported.
5770 On Nios II, the ABI is documented here:
5771 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
5773 ==> U-Boot will use gp to hold a pointer to the global data
5775 Note: on Nios II, we give "-G0" option to gcc and don't use gp
5776 to access small data sections, so gp is free.
5778 On NDS32, the following registers are used:
5780 R0-R1: argument/return
5782 R15: temporary register for assembler
5783 R16: trampoline register
5784 R28: frame pointer (FP)
5785 R29: global pointer (GP)
5786 R30: link register (LP)
5787 R31: stack pointer (SP)
5788 PC: program counter (PC)
5790 ==> U-Boot will use R10 to hold a pointer to the global data
5792 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
5793 or current versions of GCC may "optimize" the code too much.
5798 U-Boot runs in system state and uses physical addresses, i.e. the
5799 MMU is not used either for address mapping nor for memory protection.
5801 The available memory is mapped to fixed addresses using the memory
5802 controller. In this process, a contiguous block is formed for each
5803 memory type (Flash, SDRAM, SRAM), even when it consists of several
5804 physical memory banks.
5806 U-Boot is installed in the first 128 kB of the first Flash bank (on
5807 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
5808 booting and sizing and initializing DRAM, the code relocates itself
5809 to the upper end of DRAM. Immediately below the U-Boot code some
5810 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
5811 configuration setting]. Below that, a structure with global Board
5812 Info data is placed, followed by the stack (growing downward).
5814 Additionally, some exception handler code is copied to the low 8 kB
5815 of DRAM (0x00000000 ... 0x00001FFF).
5817 So a typical memory configuration with 16 MB of DRAM could look like
5820 0x0000 0000 Exception Vector code
5823 0x0000 2000 Free for Application Use
5829 0x00FB FF20 Monitor Stack (Growing downward)
5830 0x00FB FFAC Board Info Data and permanent copy of global data
5831 0x00FC 0000 Malloc Arena
5834 0x00FE 0000 RAM Copy of Monitor Code
5835 ... eventually: LCD or video framebuffer
5836 ... eventually: pRAM (Protected RAM - unchanged by reset)
5837 0x00FF FFFF [End of RAM]
5840 System Initialization:
5841 ----------------------
5843 In the reset configuration, U-Boot starts at the reset entry point
5844 (on most PowerPC systems at address 0x00000100). Because of the reset
5845 configuration for CS0# this is a mirror of the on board Flash memory.
5846 To be able to re-map memory U-Boot then jumps to its link address.
5847 To be able to implement the initialization code in C, a (small!)
5848 initial stack is set up in the internal Dual Ported RAM (in case CPUs
5849 which provide such a feature like MPC8xx or MPC8260), or in a locked
5850 part of the data cache. After that, U-Boot initializes the CPU core,
5851 the caches and the SIU.
5853 Next, all (potentially) available memory banks are mapped using a
5854 preliminary mapping. For example, we put them on 512 MB boundaries
5855 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
5856 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
5857 programmed for SDRAM access. Using the temporary configuration, a
5858 simple memory test is run that determines the size of the SDRAM
5861 When there is more than one SDRAM bank, and the banks are of
5862 different size, the largest is mapped first. For equal size, the first
5863 bank (CS2#) is mapped first. The first mapping is always for address
5864 0x00000000, with any additional banks following immediately to create
5865 contiguous memory starting from 0.
5867 Then, the monitor installs itself at the upper end of the SDRAM area
5868 and allocates memory for use by malloc() and for the global Board
5869 Info data; also, the exception vector code is copied to the low RAM
5870 pages, and the final stack is set up.
5872 Only after this relocation will you have a "normal" C environment;
5873 until that you are restricted in several ways, mostly because you are
5874 running from ROM, and because the code will have to be relocated to a
5878 U-Boot Porting Guide:
5879 ----------------------
5881 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
5885 int main(int argc, char *argv[])
5887 sighandler_t no_more_time;
5889 signal(SIGALRM, no_more_time);
5890 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
5892 if (available_money > available_manpower) {
5893 Pay consultant to port U-Boot;
5897 Download latest U-Boot source;
5899 Subscribe to u-boot mailing list;
5902 email("Hi, I am new to U-Boot, how do I get started?");
5905 Read the README file in the top level directory;
5906 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
5907 Read applicable doc/*.README;
5908 Read the source, Luke;
5909 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
5912 if (available_money > toLocalCurrency ($2500))
5915 Add a lot of aggravation and time;
5917 if (a similar board exists) { /* hopefully... */
5918 cp -a board/<similar> board/<myboard>
5919 cp include/configs/<similar>.h include/configs/<myboard>.h
5921 Create your own board support subdirectory;
5922 Create your own board include/configs/<myboard>.h file;
5924 Edit new board/<myboard> files
5925 Edit new include/configs/<myboard>.h
5930 Add / modify source code;
5934 email("Hi, I am having problems...");
5936 Send patch file to the U-Boot email list;
5937 if (reasonable critiques)
5938 Incorporate improvements from email list code review;
5940 Defend code as written;
5946 void no_more_time (int sig)
5955 All contributions to U-Boot should conform to the Linux kernel
5956 coding style; see the file "Documentation/CodingStyle" and the script
5957 "scripts/Lindent" in your Linux kernel source directory.
5959 Source files originating from a different project (for example the
5960 MTD subsystem) are generally exempt from these guidelines and are not
5961 reformatted to ease subsequent migration to newer versions of those
5964 Please note that U-Boot is implemented in C (and to some small parts in
5965 Assembler); no C++ is used, so please do not use C++ style comments (//)
5968 Please also stick to the following formatting rules:
5969 - remove any trailing white space
5970 - use TAB characters for indentation and vertical alignment, not spaces
5971 - make sure NOT to use DOS '\r\n' line feeds
5972 - do not add more than 2 consecutive empty lines to source files
5973 - do not add trailing empty lines to source files
5975 Submissions which do not conform to the standards may be returned
5976 with a request to reformat the changes.
5982 Since the number of patches for U-Boot is growing, we need to
5983 establish some rules. Submissions which do not conform to these rules
5984 may be rejected, even when they contain important and valuable stuff.
5986 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
5988 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
5989 see http://lists.denx.de/mailman/listinfo/u-boot
5991 When you send a patch, please include the following information with
5994 * For bug fixes: a description of the bug and how your patch fixes
5995 this bug. Please try to include a way of demonstrating that the
5996 patch actually fixes something.
5998 * For new features: a description of the feature and your
6001 * A CHANGELOG entry as plaintext (separate from the patch)
6003 * For major contributions, add a MAINTAINERS file with your
6004 information and associated file and directory references.
6006 * When you add support for a new board, don't forget to add a
6007 maintainer e-mail address to the boards.cfg file, too.
6009 * If your patch adds new configuration options, don't forget to
6010 document these in the README file.
6012 * The patch itself. If you are using git (which is *strongly*
6013 recommended) you can easily generate the patch using the
6014 "git format-patch". If you then use "git send-email" to send it to
6015 the U-Boot mailing list, you will avoid most of the common problems
6016 with some other mail clients.
6018 If you cannot use git, use "diff -purN OLD NEW". If your version of
6019 diff does not support these options, then get the latest version of
6022 The current directory when running this command shall be the parent
6023 directory of the U-Boot source tree (i. e. please make sure that
6024 your patch includes sufficient directory information for the
6027 We prefer patches as plain text. MIME attachments are discouraged,
6028 and compressed attachments must not be used.
6030 * If one logical set of modifications affects or creates several
6031 files, all these changes shall be submitted in a SINGLE patch file.
6033 * Changesets that contain different, unrelated modifications shall be
6034 submitted as SEPARATE patches, one patch per changeset.
6039 * Before sending the patch, run the buildman script on your patched
6040 source tree and make sure that no errors or warnings are reported
6041 for any of the boards.
6043 * Keep your modifications to the necessary minimum: A patch
6044 containing several unrelated changes or arbitrary reformats will be
6045 returned with a request to re-formatting / split it.
6047 * If you modify existing code, make sure that your new code does not
6048 add to the memory footprint of the code ;-) Small is beautiful!
6049 When adding new features, these should compile conditionally only
6050 (using #ifdef), and the resulting code with the new feature
6051 disabled must not need more memory than the old code without your
6054 * Remember that there is a size limit of 100 kB per message on the
6055 u-boot mailing list. Bigger patches will be moderated. If they are
6056 reasonable and not too big, they will be acknowledged. But patches
6057 bigger than the size limit should be avoided.