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_FUSE * Device fuse support
848 CONFIG_CMD_GETTIME * Get time since boot
849 CONFIG_CMD_GO * the 'go' command (exec code)
850 CONFIG_CMD_GREPENV * search environment
851 CONFIG_CMD_HASH * calculate hash / digest
852 CONFIG_CMD_I2C * I2C serial bus support
853 CONFIG_CMD_IDE * IDE harddisk support
854 CONFIG_CMD_IMI iminfo
855 CONFIG_CMD_IMLS List all images found in NOR flash
856 CONFIG_CMD_IMLS_NAND * List all images found in NAND flash
857 CONFIG_CMD_IMMAP * IMMR dump support
858 CONFIG_CMD_IOTRACE * I/O tracing for debugging
859 CONFIG_CMD_IMPORTENV * import an environment
860 CONFIG_CMD_INI * import data from an ini file into the env
861 CONFIG_CMD_IRQ * irqinfo
862 CONFIG_CMD_ITEST Integer/string test of 2 values
863 CONFIG_CMD_JFFS2 * JFFS2 Support
864 CONFIG_CMD_KGDB * kgdb
865 CONFIG_CMD_LDRINFO * ldrinfo (display Blackfin loader)
866 CONFIG_CMD_LINK_LOCAL * link-local IP address auto-configuration
868 CONFIG_CMD_LOADB loadb
869 CONFIG_CMD_LOADS loads
870 CONFIG_CMD_MD5SUM * print md5 message digest
871 (requires CONFIG_CMD_MEMORY and CONFIG_MD5)
872 CONFIG_CMD_MEMINFO * Display detailed memory information
873 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
875 CONFIG_CMD_MEMTEST * mtest
876 CONFIG_CMD_MISC Misc functions like sleep etc
877 CONFIG_CMD_MMC * MMC memory mapped support
878 CONFIG_CMD_MII * MII utility commands
879 CONFIG_CMD_MTDPARTS * MTD partition support
880 CONFIG_CMD_NAND * NAND support
881 CONFIG_CMD_NET bootp, tftpboot, rarpboot
882 CONFIG_CMD_NFS NFS support
883 CONFIG_CMD_PCA953X * PCA953x I2C gpio commands
884 CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command
885 CONFIG_CMD_PCI * pciinfo
886 CONFIG_CMD_PCMCIA * PCMCIA support
887 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
889 CONFIG_CMD_PORTIO * Port I/O
890 CONFIG_CMD_READ * Read raw data from partition
891 CONFIG_CMD_REGINFO * Register dump
892 CONFIG_CMD_RUN run command in env variable
893 CONFIG_CMD_SANDBOX * sb command to access sandbox features
894 CONFIG_CMD_SAVES * save S record dump
895 CONFIG_SCSI * SCSI Support
896 CONFIG_CMD_SDRAM * print SDRAM configuration information
897 (requires CONFIG_CMD_I2C)
898 CONFIG_CMD_SETGETDCR Support for DCR Register access
900 CONFIG_CMD_SF * Read/write/erase SPI NOR flash
901 CONFIG_CMD_SHA1SUM * print sha1 memory digest
902 (requires CONFIG_CMD_MEMORY)
903 CONFIG_CMD_SOFTSWITCH * Soft switch setting command for BF60x
904 CONFIG_CMD_SOURCE "source" command Support
905 CONFIG_CMD_SPI * SPI serial bus support
906 CONFIG_CMD_TFTPSRV * TFTP transfer in server mode
907 CONFIG_CMD_TFTPPUT * TFTP put command (upload)
908 CONFIG_CMD_TIME * run command and report execution time (ARM specific)
909 CONFIG_CMD_TIMER * access to the system tick timer
910 CONFIG_CMD_USB * USB support
911 CONFIG_CMD_CDP * Cisco Discover Protocol support
912 CONFIG_CMD_MFSL * Microblaze FSL support
913 CONFIG_CMD_XIMG Load part of Multi Image
914 CONFIG_CMD_UUID * Generate random UUID or GUID string
916 EXAMPLE: If you want all functions except of network
917 support you can write:
919 #include "config_cmd_all.h"
920 #undef CONFIG_CMD_NET
923 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
925 Note: Don't enable the "icache" and "dcache" commands
926 (configuration option CONFIG_CMD_CACHE) unless you know
927 what you (and your U-Boot users) are doing. Data
928 cache cannot be enabled on systems like the 8xx or
929 8260 (where accesses to the IMMR region must be
930 uncached), and it cannot be disabled on all other
931 systems where we (mis-) use the data cache to hold an
932 initial stack and some data.
935 XXX - this list needs to get updated!
937 - Removal of commands
938 If no commands are needed to boot, you can disable
939 CONFIG_CMDLINE to remove them. In this case, the command line
940 will not be available, and when U-Boot wants to execute the
941 boot command (on start-up) it will call board_run_command()
942 instead. This can reduce image size significantly for very
943 simple boot procedures.
945 - Regular expression support:
947 If this variable is defined, U-Boot is linked against
948 the SLRE (Super Light Regular Expression) library,
949 which adds regex support to some commands, as for
950 example "env grep" and "setexpr".
954 If this variable is defined, U-Boot will use a device tree
955 to configure its devices, instead of relying on statically
956 compiled #defines in the board file. This option is
957 experimental and only available on a few boards. The device
958 tree is available in the global data as gd->fdt_blob.
960 U-Boot needs to get its device tree from somewhere. This can
961 be done using one of the three options below:
964 If this variable is defined, U-Boot will embed a device tree
965 binary in its image. This device tree file should be in the
966 board directory and called <soc>-<board>.dts. The binary file
967 is then picked up in board_init_f() and made available through
968 the global data structure as gd->blob.
971 If this variable is defined, U-Boot will build a device tree
972 binary. It will be called u-boot.dtb. Architecture-specific
973 code will locate it at run-time. Generally this works by:
975 cat u-boot.bin u-boot.dtb >image.bin
977 and in fact, U-Boot does this for you, creating a file called
978 u-boot-dtb.bin which is useful in the common case. You can
979 still use the individual files if you need something more
983 If this variable is defined, U-Boot will use the device tree
984 provided by the board at runtime instead of embedding one with
985 the image. Only boards defining board_fdt_blob_setup() support
986 this option (see include/fdtdec.h file).
990 If this variable is defined, it enables watchdog
991 support for the SoC. There must be support in the SoC
992 specific code for a watchdog. For the 8xx and 8260
993 CPUs, the SIU Watchdog feature is enabled in the SYPCR
994 register. When supported for a specific SoC is
995 available, then no further board specific code should
999 When using a watchdog circuitry external to the used
1000 SoC, then define this variable and provide board
1001 specific code for the "hw_watchdog_reset" function.
1003 CONFIG_AT91_HW_WDT_TIMEOUT
1004 specify the timeout in seconds. default 2 seconds.
1007 CONFIG_VERSION_VARIABLE
1008 If this variable is defined, an environment variable
1009 named "ver" is created by U-Boot showing the U-Boot
1010 version as printed by the "version" command.
1011 Any change to this variable will be reverted at the
1016 When CONFIG_CMD_DATE is selected, the type of the RTC
1017 has to be selected, too. Define exactly one of the
1020 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
1021 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
1022 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC
1023 CONFIG_RTC_MC146818 - use MC146818 RTC
1024 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
1025 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
1026 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
1027 CONFIG_RTC_DS1339 - use Maxim, Inc. DS1339 RTC
1028 CONFIG_RTC_DS164x - use Dallas DS164x RTC
1029 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
1030 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
1031 CONFIG_SYS_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
1032 CONFIG_SYS_RV3029_TCR - enable trickle charger on
1035 Note that if the RTC uses I2C, then the I2C interface
1036 must also be configured. See I2C Support, below.
1039 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
1041 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
1042 chip-ngpio pairs that tell the PCA953X driver the number of
1043 pins supported by a particular chip.
1045 Note that if the GPIO device uses I2C, then the I2C interface
1046 must also be configured. See I2C Support, below.
1049 When CONFIG_IO_TRACE is selected, U-Boot intercepts all I/O
1050 accesses and can checksum them or write a list of them out
1051 to memory. See the 'iotrace' command for details. This is
1052 useful for testing device drivers since it can confirm that
1053 the driver behaves the same way before and after a code
1054 change. Currently this is supported on sandbox and arm. To
1055 add support for your architecture, add '#include <iotrace.h>'
1056 to the bottom of arch/<arch>/include/asm/io.h and test.
1058 Example output from the 'iotrace stats' command is below.
1059 Note that if the trace buffer is exhausted, the checksum will
1060 still continue to operate.
1063 Start: 10000000 (buffer start address)
1064 Size: 00010000 (buffer size)
1065 Offset: 00000120 (current buffer offset)
1066 Output: 10000120 (start + offset)
1067 Count: 00000018 (number of trace records)
1068 CRC32: 9526fb66 (CRC32 of all trace records)
1070 - Timestamp Support:
1072 When CONFIG_TIMESTAMP is selected, the timestamp
1073 (date and time) of an image is printed by image
1074 commands like bootm or iminfo. This option is
1075 automatically enabled when you select CONFIG_CMD_DATE .
1077 - Partition Labels (disklabels) Supported:
1078 Zero or more of the following:
1079 CONFIG_MAC_PARTITION Apple's MacOS partition table.
1080 CONFIG_DOS_PARTITION MS Dos partition table, traditional on the
1081 Intel architecture, USB sticks, etc.
1082 CONFIG_ISO_PARTITION ISO partition table, used on CDROM etc.
1083 CONFIG_EFI_PARTITION GPT partition table, common when EFI is the
1084 bootloader. Note 2TB partition limit; see
1086 CONFIG_MTD_PARTITIONS Memory Technology Device partition table.
1088 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
1089 CONFIG_SCSI) you must configure support for at
1090 least one non-MTD partition type as well.
1093 CONFIG_IDE_RESET_ROUTINE - this is defined in several
1094 board configurations files but used nowhere!
1096 CONFIG_IDE_RESET - is this is defined, IDE Reset will
1097 be performed by calling the function
1098 ide_set_reset(int reset)
1099 which has to be defined in a board specific file
1104 Set this to enable ATAPI support.
1109 Set this to enable support for disks larger than 137GB
1110 Also look at CONFIG_SYS_64BIT_LBA.
1111 Whithout these , LBA48 support uses 32bit variables and will 'only'
1112 support disks up to 2.1TB.
1114 CONFIG_SYS_64BIT_LBA:
1115 When enabled, makes the IDE subsystem use 64bit sector addresses.
1119 At the moment only there is only support for the
1120 SYM53C8XX SCSI controller; define
1121 CONFIG_SCSI_SYM53C8XX to enable it.
1123 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
1124 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
1125 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
1126 maximum numbers of LUNs, SCSI ID's and target
1128 CONFIG_SYS_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
1130 The environment variable 'scsidevs' is set to the number of
1131 SCSI devices found during the last scan.
1133 - NETWORK Support (PCI):
1135 Support for Intel 8254x/8257x gigabit chips.
1138 Utility code for direct access to the SPI bus on Intel 8257x.
1139 This does not do anything useful unless you set at least one
1140 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
1142 CONFIG_E1000_SPI_GENERIC
1143 Allow generic access to the SPI bus on the Intel 8257x, for
1144 example with the "sspi" command.
1147 Management command for E1000 devices. When used on devices
1148 with SPI support you can reprogram the EEPROM from U-Boot.
1151 Support for Intel 82557/82559/82559ER chips.
1152 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
1153 write routine for first time initialisation.
1156 Support for Digital 2114x chips.
1157 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
1158 modem chip initialisation (KS8761/QS6611).
1161 Support for National dp83815 chips.
1164 Support for National dp8382[01] gigabit chips.
1166 - NETWORK Support (other):
1168 CONFIG_DRIVER_AT91EMAC
1169 Support for AT91RM9200 EMAC.
1172 Define this to use reduced MII inteface
1174 CONFIG_DRIVER_AT91EMAC_QUIET
1175 If this defined, the driver is quiet.
1176 The driver doen't show link status messages.
1178 CONFIG_CALXEDA_XGMAC
1179 Support for the Calxeda XGMAC device
1182 Support for SMSC's LAN91C96 chips.
1184 CONFIG_LAN91C96_USE_32_BIT
1185 Define this to enable 32 bit addressing
1188 Support for SMSC's LAN91C111 chip
1190 CONFIG_SMC91111_BASE
1191 Define this to hold the physical address
1192 of the device (I/O space)
1194 CONFIG_SMC_USE_32_BIT
1195 Define this if data bus is 32 bits
1197 CONFIG_SMC_USE_IOFUNCS
1198 Define this to use i/o functions instead of macros
1199 (some hardware wont work with macros)
1201 CONFIG_DRIVER_TI_EMAC
1202 Support for davinci emac
1204 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
1205 Define this if you have more then 3 PHYs.
1208 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
1210 CONFIG_FTGMAC100_EGIGA
1211 Define this to use GE link update with gigabit PHY.
1212 Define this if FTGMAC100 is connected to gigabit PHY.
1213 If your system has 10/100 PHY only, it might not occur
1214 wrong behavior. Because PHY usually return timeout or
1215 useless data when polling gigabit status and gigabit
1216 control registers. This behavior won't affect the
1217 correctnessof 10/100 link speed update.
1220 Support for SMSC's LAN911x and LAN921x chips
1223 Define this to hold the physical address
1224 of the device (I/O space)
1226 CONFIG_SMC911X_32_BIT
1227 Define this if data bus is 32 bits
1229 CONFIG_SMC911X_16_BIT
1230 Define this if data bus is 16 bits. If your processor
1231 automatically converts one 32 bit word to two 16 bit
1232 words you may also try CONFIG_SMC911X_32_BIT.
1235 Support for Renesas on-chip Ethernet controller
1237 CONFIG_SH_ETHER_USE_PORT
1238 Define the number of ports to be used
1240 CONFIG_SH_ETHER_PHY_ADDR
1241 Define the ETH PHY's address
1243 CONFIG_SH_ETHER_CACHE_WRITEBACK
1244 If this option is set, the driver enables cache flush.
1248 Support for PWM module on the imx6.
1252 Support TPM devices.
1254 CONFIG_TPM_TIS_INFINEON
1255 Support for Infineon i2c bus TPM devices. Only one device
1256 per system is supported at this time.
1258 CONFIG_TPM_TIS_I2C_BURST_LIMITATION
1259 Define the burst count bytes upper limit
1262 Support for STMicroelectronics TPM devices. Requires DM_TPM support.
1264 CONFIG_TPM_ST33ZP24_I2C
1265 Support for STMicroelectronics ST33ZP24 I2C devices.
1266 Requires TPM_ST33ZP24 and I2C.
1268 CONFIG_TPM_ST33ZP24_SPI
1269 Support for STMicroelectronics ST33ZP24 SPI devices.
1270 Requires TPM_ST33ZP24 and SPI.
1272 CONFIG_TPM_ATMEL_TWI
1273 Support for Atmel TWI TPM device. Requires I2C support.
1276 Support for generic parallel port TPM devices. Only one device
1277 per system is supported at this time.
1279 CONFIG_TPM_TIS_BASE_ADDRESS
1280 Base address where the generic TPM device is mapped
1281 to. Contemporary x86 systems usually map it at
1285 Add tpm monitor functions.
1286 Requires CONFIG_TPM. If CONFIG_TPM_AUTH_SESSIONS is set, also
1287 provides monitor access to authorized functions.
1290 Define this to enable the TPM support library which provides
1291 functional interfaces to some TPM commands.
1292 Requires support for a TPM device.
1294 CONFIG_TPM_AUTH_SESSIONS
1295 Define this to enable authorized functions in the TPM library.
1296 Requires CONFIG_TPM and CONFIG_SHA1.
1299 At the moment only the UHCI host controller is
1300 supported (PIP405, MIP405, MPC5200); define
1301 CONFIG_USB_UHCI to enable it.
1302 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
1303 and define CONFIG_USB_STORAGE to enable the USB
1306 Supported are USB Keyboards and USB Floppy drives
1308 MPC5200 USB requires additional defines:
1310 for 528 MHz Clock: 0x0001bbbb
1314 for differential drivers: 0x00001000
1315 for single ended drivers: 0x00005000
1316 for differential drivers on PSC3: 0x00000100
1317 for single ended drivers on PSC3: 0x00004100
1318 CONFIG_SYS_USB_EVENT_POLL
1319 May be defined to allow interrupt polling
1320 instead of using asynchronous interrupts
1322 CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
1323 txfilltuning field in the EHCI controller on reset.
1325 CONFIG_USB_DWC2_REG_ADDR the physical CPU address of the DWC2
1326 HW module registers.
1329 Define the below if you wish to use the USB console.
1330 Once firmware is rebuilt from a serial console issue the
1331 command "setenv stdin usbtty; setenv stdout usbtty" and
1332 attach your USB cable. The Unix command "dmesg" should print
1333 it has found a new device. The environment variable usbtty
1334 can be set to gserial or cdc_acm to enable your device to
1335 appear to a USB host as a Linux gserial device or a
1336 Common Device Class Abstract Control Model serial device.
1337 If you select usbtty = gserial you should be able to enumerate
1339 # modprobe usbserial vendor=0xVendorID product=0xProductID
1340 else if using cdc_acm, simply setting the environment
1341 variable usbtty to be cdc_acm should suffice. The following
1342 might be defined in YourBoardName.h
1345 Define this to build a UDC device
1348 Define this to have a tty type of device available to
1349 talk to the UDC device
1352 Define this to enable the high speed support for usb
1353 device and usbtty. If this feature is enabled, a routine
1354 int is_usbd_high_speed(void)
1355 also needs to be defined by the driver to dynamically poll
1356 whether the enumeration has succeded at high speed or full
1359 CONFIG_SYS_CONSOLE_IS_IN_ENV
1360 Define this if you want stdin, stdout &/or stderr to
1364 CONFIG_SYS_USB_EXTC_CLK 0xBLAH
1365 Derive USB clock from external clock "blah"
1366 - CONFIG_SYS_USB_EXTC_CLK 0x02
1368 If you have a USB-IF assigned VendorID then you may wish to
1369 define your own vendor specific values either in BoardName.h
1370 or directly in usbd_vendor_info.h. If you don't define
1371 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
1372 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
1373 should pretend to be a Linux device to it's target host.
1375 CONFIG_USBD_MANUFACTURER
1376 Define this string as the name of your company for
1377 - CONFIG_USBD_MANUFACTURER "my company"
1379 CONFIG_USBD_PRODUCT_NAME
1380 Define this string as the name of your product
1381 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
1383 CONFIG_USBD_VENDORID
1384 Define this as your assigned Vendor ID from the USB
1385 Implementors Forum. This *must* be a genuine Vendor ID
1386 to avoid polluting the USB namespace.
1387 - CONFIG_USBD_VENDORID 0xFFFF
1389 CONFIG_USBD_PRODUCTID
1390 Define this as the unique Product ID
1392 - CONFIG_USBD_PRODUCTID 0xFFFF
1394 - ULPI Layer Support:
1395 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
1396 the generic ULPI layer. The generic layer accesses the ULPI PHY
1397 via the platform viewport, so you need both the genric layer and
1398 the viewport enabled. Currently only Chipidea/ARC based
1399 viewport is supported.
1400 To enable the ULPI layer support, define CONFIG_USB_ULPI and
1401 CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
1402 If your ULPI phy needs a different reference clock than the
1403 standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to
1404 the appropriate value in Hz.
1407 The MMC controller on the Intel PXA is supported. To
1408 enable this define CONFIG_MMC. The MMC can be
1409 accessed from the boot prompt by mapping the device
1410 to physical memory similar to flash. Command line is
1411 enabled with CONFIG_CMD_MMC. The MMC driver also works with
1412 the FAT fs. This is enabled with CONFIG_CMD_FAT.
1415 Support for Renesas on-chip MMCIF controller
1417 CONFIG_SH_MMCIF_ADDR
1418 Define the base address of MMCIF registers
1421 Define the clock frequency for MMCIF
1423 CONFIG_SUPPORT_EMMC_BOOT
1424 Enable some additional features of the eMMC boot partitions.
1426 CONFIG_SUPPORT_EMMC_RPMB
1427 Enable the commands for reading, writing and programming the
1428 key for the Replay Protection Memory Block partition in eMMC.
1430 - USB Device Firmware Update (DFU) class support:
1431 CONFIG_USB_FUNCTION_DFU
1432 This enables the USB portion of the DFU USB class
1435 This enables the command "dfu" which is used to have
1436 U-Boot create a DFU class device via USB. This command
1437 requires that the "dfu_alt_info" environment variable be
1438 set and define the alt settings to expose to the host.
1441 This enables support for exposing (e)MMC devices via DFU.
1444 This enables support for exposing NAND devices via DFU.
1447 This enables support for exposing RAM via DFU.
1448 Note: DFU spec refer to non-volatile memory usage, but
1449 allow usages beyond the scope of spec - here RAM usage,
1450 one that would help mostly the developer.
1452 CONFIG_SYS_DFU_DATA_BUF_SIZE
1453 Dfu transfer uses a buffer before writing data to the
1454 raw storage device. Make the size (in bytes) of this buffer
1455 configurable. The size of this buffer is also configurable
1456 through the "dfu_bufsiz" environment variable.
1458 CONFIG_SYS_DFU_MAX_FILE_SIZE
1459 When updating files rather than the raw storage device,
1460 we use a static buffer to copy the file into and then write
1461 the buffer once we've been given the whole file. Define
1462 this to the maximum filesize (in bytes) for the buffer.
1463 Default is 4 MiB if undefined.
1465 DFU_DEFAULT_POLL_TIMEOUT
1466 Poll timeout [ms], is the timeout a device can send to the
1467 host. The host must wait for this timeout before sending
1468 a subsequent DFU_GET_STATUS request to the device.
1470 DFU_MANIFEST_POLL_TIMEOUT
1471 Poll timeout [ms], which the device sends to the host when
1472 entering dfuMANIFEST state. Host waits this timeout, before
1473 sending again an USB request to the device.
1475 - USB Device Android Fastboot support:
1476 CONFIG_USB_FUNCTION_FASTBOOT
1477 This enables the USB part of the fastboot gadget
1480 This enables the command "fastboot" which enables the Android
1481 fastboot mode for the platform's USB device. Fastboot is a USB
1482 protocol for downloading images, flashing and device control
1483 used on Android devices.
1484 See doc/README.android-fastboot for more information.
1486 CONFIG_ANDROID_BOOT_IMAGE
1487 This enables support for booting images which use the Android
1488 image format header.
1490 CONFIG_FASTBOOT_BUF_ADDR
1491 The fastboot protocol requires a large memory buffer for
1492 downloads. Define this to the starting RAM address to use for
1495 CONFIG_FASTBOOT_BUF_SIZE
1496 The fastboot protocol requires a large memory buffer for
1497 downloads. This buffer should be as large as possible for a
1498 platform. Define this to the size available RAM for fastboot.
1500 CONFIG_FASTBOOT_FLASH
1501 The fastboot protocol includes a "flash" command for writing
1502 the downloaded image to a non-volatile storage device. Define
1503 this to enable the "fastboot flash" command.
1505 CONFIG_FASTBOOT_FLASH_MMC_DEV
1506 The fastboot "flash" command requires additional information
1507 regarding the non-volatile storage device. Define this to
1508 the eMMC device that fastboot should use to store the image.
1510 CONFIG_FASTBOOT_GPT_NAME
1511 The fastboot "flash" command supports writing the downloaded
1512 image to the Protective MBR and the Primary GUID Partition
1513 Table. (Additionally, this downloaded image is post-processed
1514 to generate and write the Backup GUID Partition Table.)
1515 This occurs when the specified "partition name" on the
1516 "fastboot flash" command line matches this value.
1517 The default is "gpt" if undefined.
1519 CONFIG_FASTBOOT_MBR_NAME
1520 The fastboot "flash" command supports writing the downloaded
1522 This occurs when the "partition name" specified on the
1523 "fastboot flash" command line matches this value.
1524 If not defined the default value "mbr" is used.
1526 - Journaling Flash filesystem support:
1528 Define these for a default partition on a NAND device
1530 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1531 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1532 Define these for a default partition on a NOR device
1534 - FAT(File Allocation Table) filesystem write function support:
1537 Define this to enable support for saving memory data as a
1538 file in FAT formatted partition.
1540 This will also enable the command "fatwrite" enabling the
1541 user to write files to FAT.
1543 - FAT(File Allocation Table) filesystem cluster size:
1544 CONFIG_FS_FAT_MAX_CLUSTSIZE
1546 Define the max cluster size for fat operations else
1547 a default value of 65536 will be defined.
1550 See Kconfig help for available keyboard drivers.
1554 Define this to enable a custom keyboard support.
1555 This simply calls drv_keyboard_init() which must be
1556 defined in your board-specific files. This option is deprecated
1557 and is only used by novena. For new boards, use driver model
1562 Enable the Freescale DIU video driver. Reference boards for
1563 SOCs that have a DIU should define this macro to enable DIU
1564 support, and should also define these other macros:
1569 CONFIG_VIDEO_SW_CURSOR
1570 CONFIG_VGA_AS_SINGLE_DEVICE
1572 CONFIG_VIDEO_BMP_LOGO
1574 The DIU driver will look for the 'video-mode' environment
1575 variable, and if defined, enable the DIU as a console during
1576 boot. See the documentation file doc/README.video for a
1577 description of this variable.
1579 - LCD Support: CONFIG_LCD
1581 Define this to enable LCD support (for output to LCD
1582 display); also select one of the supported displays
1583 by defining one of these:
1587 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1589 CONFIG_NEC_NL6448AC33:
1591 NEC NL6448AC33-18. Active, color, single scan.
1593 CONFIG_NEC_NL6448BC20
1595 NEC NL6448BC20-08. 6.5", 640x480.
1596 Active, color, single scan.
1598 CONFIG_NEC_NL6448BC33_54
1600 NEC NL6448BC33-54. 10.4", 640x480.
1601 Active, color, single scan.
1605 Sharp 320x240. Active, color, single scan.
1606 It isn't 16x9, and I am not sure what it is.
1608 CONFIG_SHARP_LQ64D341
1610 Sharp LQ64D341 display, 640x480.
1611 Active, color, single scan.
1615 HLD1045 display, 640x480.
1616 Active, color, single scan.
1620 Optrex CBL50840-2 NF-FW 99 22 M5
1622 Hitachi LMG6912RPFC-00T
1626 320x240. Black & white.
1628 CONFIG_LCD_ALIGNMENT
1630 Normally the LCD is page-aligned (typically 4KB). If this is
1631 defined then the LCD will be aligned to this value instead.
1632 For ARM it is sometimes useful to use MMU_SECTION_SIZE
1633 here, since it is cheaper to change data cache settings on
1634 a per-section basis.
1639 Sometimes, for example if the display is mounted in portrait
1640 mode or even if it's mounted landscape but rotated by 180degree,
1641 we need to rotate our content of the display relative to the
1642 framebuffer, so that user can read the messages which are
1644 Once CONFIG_LCD_ROTATION is defined, the lcd_console will be
1645 initialized with a given rotation from "vl_rot" out of
1646 "vidinfo_t" which is provided by the board specific code.
1647 The value for vl_rot is coded as following (matching to
1648 fbcon=rotate:<n> linux-kernel commandline):
1649 0 = no rotation respectively 0 degree
1650 1 = 90 degree rotation
1651 2 = 180 degree rotation
1652 3 = 270 degree rotation
1654 If CONFIG_LCD_ROTATION is not defined, the console will be
1655 initialized with 0degree rotation.
1659 Support drawing of RLE8-compressed bitmaps on the LCD.
1663 Enables an 'i2c edid' command which can read EDID
1664 information over I2C from an attached LCD display.
1666 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1668 If this option is set, the environment is checked for
1669 a variable "splashimage". If found, the usual display
1670 of logo, copyright and system information on the LCD
1671 is suppressed and the BMP image at the address
1672 specified in "splashimage" is loaded instead. The
1673 console is redirected to the "nulldev", too. This
1674 allows for a "silent" boot where a splash screen is
1675 loaded very quickly after power-on.
1677 CONFIG_SPLASHIMAGE_GUARD
1679 If this option is set, then U-Boot will prevent the environment
1680 variable "splashimage" from being set to a problematic address
1681 (see doc/README.displaying-bmps).
1682 This option is useful for targets where, due to alignment
1683 restrictions, an improperly aligned BMP image will cause a data
1684 abort. If you think you will not have problems with unaligned
1685 accesses (for example because your toolchain prevents them)
1686 there is no need to set this option.
1688 CONFIG_SPLASH_SCREEN_ALIGN
1690 If this option is set the splash image can be freely positioned
1691 on the screen. Environment variable "splashpos" specifies the
1692 position as "x,y". If a positive number is given it is used as
1693 number of pixel from left/top. If a negative number is given it
1694 is used as number of pixel from right/bottom. You can also
1695 specify 'm' for centering the image.
1698 setenv splashpos m,m
1699 => image at center of screen
1701 setenv splashpos 30,20
1702 => image at x = 30 and y = 20
1704 setenv splashpos -10,m
1705 => vertically centered image
1706 at x = dspWidth - bmpWidth - 9
1708 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1710 If this option is set, additionally to standard BMP
1711 images, gzipped BMP images can be displayed via the
1712 splashscreen support or the bmp command.
1714 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1716 If this option is set, 8-bit RLE compressed BMP images
1717 can be displayed via the splashscreen support or the
1720 - Compression support:
1723 Enabled by default to support gzip compressed images.
1727 If this option is set, support for bzip2 compressed
1728 images is included. If not, only uncompressed and gzip
1729 compressed images are supported.
1731 NOTE: the bzip2 algorithm requires a lot of RAM, so
1732 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1737 If this option is set, support for lzma compressed
1740 Note: The LZMA algorithm adds between 2 and 4KB of code and it
1741 requires an amount of dynamic memory that is given by the
1744 (1846 + 768 << (lc + lp)) * sizeof(uint16)
1746 Where lc and lp stand for, respectively, Literal context bits
1747 and Literal pos bits.
1749 This value is upper-bounded by 14MB in the worst case. Anyway,
1750 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
1751 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
1752 a very small buffer.
1754 Use the lzmainfo tool to determinate the lc and lp values and
1755 then calculate the amount of needed dynamic memory (ensuring
1756 the appropriate CONFIG_SYS_MALLOC_LEN value).
1760 If this option is set, support for LZO compressed images
1766 The address of PHY on MII bus.
1768 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1770 The clock frequency of the MII bus
1774 If this option is set, support for speed/duplex
1775 detection of gigabit PHY is included.
1777 CONFIG_PHY_RESET_DELAY
1779 Some PHY like Intel LXT971A need extra delay after
1780 reset before any MII register access is possible.
1781 For such PHY, set this option to the usec delay
1782 required. (minimum 300usec for LXT971A)
1784 CONFIG_PHY_CMD_DELAY (ppc4xx)
1786 Some PHY like Intel LXT971A need extra delay after
1787 command issued before MII status register can be read
1792 Define a default value for the IP address to use for
1793 the default Ethernet interface, in case this is not
1794 determined through e.g. bootp.
1795 (Environment variable "ipaddr")
1797 - Server IP address:
1800 Defines a default value for the IP address of a TFTP
1801 server to contact when using the "tftboot" command.
1802 (Environment variable "serverip")
1804 CONFIG_KEEP_SERVERADDR
1806 Keeps the server's MAC address, in the env 'serveraddr'
1807 for passing to bootargs (like Linux's netconsole option)
1809 - Gateway IP address:
1812 Defines a default value for the IP address of the
1813 default router where packets to other networks are
1815 (Environment variable "gatewayip")
1820 Defines a default value for the subnet mask (or
1821 routing prefix) which is used to determine if an IP
1822 address belongs to the local subnet or needs to be
1823 forwarded through a router.
1824 (Environment variable "netmask")
1826 - Multicast TFTP Mode:
1829 Defines whether you want to support multicast TFTP as per
1830 rfc-2090; for example to work with atftp. Lets lots of targets
1831 tftp down the same boot image concurrently. Note: the Ethernet
1832 driver in use must provide a function: mcast() to join/leave a
1835 - BOOTP Recovery Mode:
1836 CONFIG_BOOTP_RANDOM_DELAY
1838 If you have many targets in a network that try to
1839 boot using BOOTP, you may want to avoid that all
1840 systems send out BOOTP requests at precisely the same
1841 moment (which would happen for instance at recovery
1842 from a power failure, when all systems will try to
1843 boot, thus flooding the BOOTP server. Defining
1844 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1845 inserted before sending out BOOTP requests. The
1846 following delays are inserted then:
1848 1st BOOTP request: delay 0 ... 1 sec
1849 2nd BOOTP request: delay 0 ... 2 sec
1850 3rd BOOTP request: delay 0 ... 4 sec
1852 BOOTP requests: delay 0 ... 8 sec
1854 CONFIG_BOOTP_ID_CACHE_SIZE
1856 BOOTP packets are uniquely identified using a 32-bit ID. The
1857 server will copy the ID from client requests to responses and
1858 U-Boot will use this to determine if it is the destination of
1859 an incoming response. Some servers will check that addresses
1860 aren't in use before handing them out (usually using an ARP
1861 ping) and therefore take up to a few hundred milliseconds to
1862 respond. Network congestion may also influence the time it
1863 takes for a response to make it back to the client. If that
1864 time is too long, U-Boot will retransmit requests. In order
1865 to allow earlier responses to still be accepted after these
1866 retransmissions, U-Boot's BOOTP client keeps a small cache of
1867 IDs. The CONFIG_BOOTP_ID_CACHE_SIZE controls the size of this
1868 cache. The default is to keep IDs for up to four outstanding
1869 requests. Increasing this will allow U-Boot to accept offers
1870 from a BOOTP client in networks with unusually high latency.
1872 - DHCP Advanced Options:
1873 You can fine tune the DHCP functionality by defining
1874 CONFIG_BOOTP_* symbols:
1876 CONFIG_BOOTP_SUBNETMASK
1877 CONFIG_BOOTP_GATEWAY
1878 CONFIG_BOOTP_HOSTNAME
1879 CONFIG_BOOTP_NISDOMAIN
1880 CONFIG_BOOTP_BOOTPATH
1881 CONFIG_BOOTP_BOOTFILESIZE
1884 CONFIG_BOOTP_SEND_HOSTNAME
1885 CONFIG_BOOTP_NTPSERVER
1886 CONFIG_BOOTP_TIMEOFFSET
1887 CONFIG_BOOTP_VENDOREX
1888 CONFIG_BOOTP_MAY_FAIL
1890 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1891 environment variable, not the BOOTP server.
1893 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
1894 after the configured retry count, the call will fail
1895 instead of starting over. This can be used to fail over
1896 to Link-local IP address configuration if the DHCP server
1899 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1900 serverip from a DHCP server, it is possible that more
1901 than one DNS serverip is offered to the client.
1902 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1903 serverip will be stored in the additional environment
1904 variable "dnsip2". The first DNS serverip is always
1905 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1908 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1909 to do a dynamic update of a DNS server. To do this, they
1910 need the hostname of the DHCP requester.
1911 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1912 of the "hostname" environment variable is passed as
1913 option 12 to the DHCP server.
1915 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1917 A 32bit value in microseconds for a delay between
1918 receiving a "DHCP Offer" and sending the "DHCP Request".
1919 This fixes a problem with certain DHCP servers that don't
1920 respond 100% of the time to a "DHCP request". E.g. On an
1921 AT91RM9200 processor running at 180MHz, this delay needed
1922 to be *at least* 15,000 usec before a Windows Server 2003
1923 DHCP server would reply 100% of the time. I recommend at
1924 least 50,000 usec to be safe. The alternative is to hope
1925 that one of the retries will be successful but note that
1926 the DHCP timeout and retry process takes a longer than
1929 - Link-local IP address negotiation:
1930 Negotiate with other link-local clients on the local network
1931 for an address that doesn't require explicit configuration.
1932 This is especially useful if a DHCP server cannot be guaranteed
1933 to exist in all environments that the device must operate.
1935 See doc/README.link-local for more information.
1938 CONFIG_CDP_DEVICE_ID
1940 The device id used in CDP trigger frames.
1942 CONFIG_CDP_DEVICE_ID_PREFIX
1944 A two character string which is prefixed to the MAC address
1949 A printf format string which contains the ascii name of
1950 the port. Normally is set to "eth%d" which sets
1951 eth0 for the first Ethernet, eth1 for the second etc.
1953 CONFIG_CDP_CAPABILITIES
1955 A 32bit integer which indicates the device capabilities;
1956 0x00000010 for a normal host which does not forwards.
1960 An ascii string containing the version of the software.
1964 An ascii string containing the name of the platform.
1968 A 32bit integer sent on the trigger.
1970 CONFIG_CDP_POWER_CONSUMPTION
1972 A 16bit integer containing the power consumption of the
1973 device in .1 of milliwatts.
1975 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1977 A byte containing the id of the VLAN.
1979 - Status LED: CONFIG_LED_STATUS
1981 Several configurations allow to display the current
1982 status using a LED. For instance, the LED will blink
1983 fast while running U-Boot code, stop blinking as
1984 soon as a reply to a BOOTP request was received, and
1985 start blinking slow once the Linux kernel is running
1986 (supported by a status LED driver in the Linux
1987 kernel). Defining CONFIG_LED_STATUS enables this
1992 CONFIG_LED_STATUS_GPIO
1993 The status LED can be connected to a GPIO pin.
1994 In such cases, the gpio_led driver can be used as a
1995 status LED backend implementation. Define CONFIG_LED_STATUS_GPIO
1996 to include the gpio_led driver in the U-Boot binary.
1998 CONFIG_GPIO_LED_INVERTED_TABLE
1999 Some GPIO connected LEDs may have inverted polarity in which
2000 case the GPIO high value corresponds to LED off state and
2001 GPIO low value corresponds to LED on state.
2002 In such cases CONFIG_GPIO_LED_INVERTED_TABLE may be defined
2003 with a list of GPIO LEDs that have inverted polarity.
2005 - CAN Support: CONFIG_CAN_DRIVER
2007 Defining CONFIG_CAN_DRIVER enables CAN driver support
2008 on those systems that support this (optional)
2009 feature, like the TQM8xxL modules.
2011 - I2C Support: CONFIG_SYS_I2C
2013 This enable the NEW i2c subsystem, and will allow you to use
2014 i2c commands at the u-boot command line (as long as you set
2015 CONFIG_CMD_I2C in CONFIG_COMMANDS) and communicate with i2c
2016 based realtime clock chips or other i2c devices. See
2017 common/cmd_i2c.c for a description of the command line
2020 ported i2c driver to the new framework:
2021 - drivers/i2c/soft_i2c.c:
2022 - activate first bus with CONFIG_SYS_I2C_SOFT define
2023 CONFIG_SYS_I2C_SOFT_SPEED and CONFIG_SYS_I2C_SOFT_SLAVE
2024 for defining speed and slave address
2025 - activate second bus with I2C_SOFT_DECLARATIONS2 define
2026 CONFIG_SYS_I2C_SOFT_SPEED_2 and CONFIG_SYS_I2C_SOFT_SLAVE_2
2027 for defining speed and slave address
2028 - activate third bus with I2C_SOFT_DECLARATIONS3 define
2029 CONFIG_SYS_I2C_SOFT_SPEED_3 and CONFIG_SYS_I2C_SOFT_SLAVE_3
2030 for defining speed and slave address
2031 - activate fourth bus with I2C_SOFT_DECLARATIONS4 define
2032 CONFIG_SYS_I2C_SOFT_SPEED_4 and CONFIG_SYS_I2C_SOFT_SLAVE_4
2033 for defining speed and slave address
2035 - drivers/i2c/fsl_i2c.c:
2036 - activate i2c driver with CONFIG_SYS_I2C_FSL
2037 define CONFIG_SYS_FSL_I2C_OFFSET for setting the register
2038 offset CONFIG_SYS_FSL_I2C_SPEED for the i2c speed and
2039 CONFIG_SYS_FSL_I2C_SLAVE for the slave addr of the first
2041 - If your board supports a second fsl i2c bus, define
2042 CONFIG_SYS_FSL_I2C2_OFFSET for the register offset
2043 CONFIG_SYS_FSL_I2C2_SPEED for the speed and
2044 CONFIG_SYS_FSL_I2C2_SLAVE for the slave address of the
2047 - drivers/i2c/tegra_i2c.c:
2048 - activate this driver with CONFIG_SYS_I2C_TEGRA
2049 - This driver adds 4 i2c buses with a fix speed from
2050 100000 and the slave addr 0!
2052 - drivers/i2c/ppc4xx_i2c.c
2053 - activate this driver with CONFIG_SYS_I2C_PPC4XX
2054 - CONFIG_SYS_I2C_PPC4XX_CH0 activate hardware channel 0
2055 - CONFIG_SYS_I2C_PPC4XX_CH1 activate hardware channel 1
2057 - drivers/i2c/i2c_mxc.c
2058 - activate this driver with CONFIG_SYS_I2C_MXC
2059 - enable bus 1 with CONFIG_SYS_I2C_MXC_I2C1
2060 - enable bus 2 with CONFIG_SYS_I2C_MXC_I2C2
2061 - enable bus 3 with CONFIG_SYS_I2C_MXC_I2C3
2062 - enable bus 4 with CONFIG_SYS_I2C_MXC_I2C4
2063 - define speed for bus 1 with CONFIG_SYS_MXC_I2C1_SPEED
2064 - define slave for bus 1 with CONFIG_SYS_MXC_I2C1_SLAVE
2065 - define speed for bus 2 with CONFIG_SYS_MXC_I2C2_SPEED
2066 - define slave for bus 2 with CONFIG_SYS_MXC_I2C2_SLAVE
2067 - define speed for bus 3 with CONFIG_SYS_MXC_I2C3_SPEED
2068 - define slave for bus 3 with CONFIG_SYS_MXC_I2C3_SLAVE
2069 - define speed for bus 4 with CONFIG_SYS_MXC_I2C4_SPEED
2070 - define slave for bus 4 with CONFIG_SYS_MXC_I2C4_SLAVE
2071 If those defines are not set, default value is 100000
2072 for speed, and 0 for slave.
2074 - drivers/i2c/rcar_i2c.c:
2075 - activate this driver with CONFIG_SYS_I2C_RCAR
2076 - This driver adds 4 i2c buses
2078 - CONFIG_SYS_RCAR_I2C0_BASE for setting the register channel 0
2079 - CONFIG_SYS_RCAR_I2C0_SPEED for for the speed channel 0
2080 - CONFIG_SYS_RCAR_I2C1_BASE for setting the register channel 1
2081 - CONFIG_SYS_RCAR_I2C1_SPEED for for the speed channel 1
2082 - CONFIG_SYS_RCAR_I2C2_BASE for setting the register channel 2
2083 - CONFIG_SYS_RCAR_I2C2_SPEED for for the speed channel 2
2084 - CONFIG_SYS_RCAR_I2C3_BASE for setting the register channel 3
2085 - CONFIG_SYS_RCAR_I2C3_SPEED for for the speed channel 3
2086 - CONFIF_SYS_RCAR_I2C_NUM_CONTROLLERS for number of i2c buses
2088 - drivers/i2c/sh_i2c.c:
2089 - activate this driver with CONFIG_SYS_I2C_SH
2090 - This driver adds from 2 to 5 i2c buses
2092 - CONFIG_SYS_I2C_SH_BASE0 for setting the register channel 0
2093 - CONFIG_SYS_I2C_SH_SPEED0 for for the speed channel 0
2094 - CONFIG_SYS_I2C_SH_BASE1 for setting the register channel 1
2095 - CONFIG_SYS_I2C_SH_SPEED1 for for the speed channel 1
2096 - CONFIG_SYS_I2C_SH_BASE2 for setting the register channel 2
2097 - CONFIG_SYS_I2C_SH_SPEED2 for for the speed channel 2
2098 - CONFIG_SYS_I2C_SH_BASE3 for setting the register channel 3
2099 - CONFIG_SYS_I2C_SH_SPEED3 for for the speed channel 3
2100 - CONFIG_SYS_I2C_SH_BASE4 for setting the register channel 4
2101 - CONFIG_SYS_I2C_SH_SPEED4 for for the speed channel 4
2102 - CONFIG_SYS_I2C_SH_NUM_CONTROLLERS for number of i2c buses
2104 - drivers/i2c/omap24xx_i2c.c
2105 - activate this driver with CONFIG_SYS_I2C_OMAP24XX
2106 - CONFIG_SYS_OMAP24_I2C_SPEED speed channel 0
2107 - CONFIG_SYS_OMAP24_I2C_SLAVE slave addr channel 0
2108 - CONFIG_SYS_OMAP24_I2C_SPEED1 speed channel 1
2109 - CONFIG_SYS_OMAP24_I2C_SLAVE1 slave addr channel 1
2110 - CONFIG_SYS_OMAP24_I2C_SPEED2 speed channel 2
2111 - CONFIG_SYS_OMAP24_I2C_SLAVE2 slave addr channel 2
2112 - CONFIG_SYS_OMAP24_I2C_SPEED3 speed channel 3
2113 - CONFIG_SYS_OMAP24_I2C_SLAVE3 slave addr channel 3
2114 - CONFIG_SYS_OMAP24_I2C_SPEED4 speed channel 4
2115 - CONFIG_SYS_OMAP24_I2C_SLAVE4 slave addr channel 4
2117 - drivers/i2c/zynq_i2c.c
2118 - activate this driver with CONFIG_SYS_I2C_ZYNQ
2119 - set CONFIG_SYS_I2C_ZYNQ_SPEED for speed setting
2120 - set CONFIG_SYS_I2C_ZYNQ_SLAVE for slave addr
2122 - drivers/i2c/s3c24x0_i2c.c:
2123 - activate this driver with CONFIG_SYS_I2C_S3C24X0
2124 - This driver adds i2c buses (11 for Exynos5250, Exynos5420
2125 9 i2c buses for Exynos4 and 1 for S3C24X0 SoCs from Samsung)
2126 with a fix speed from 100000 and the slave addr 0!
2128 - drivers/i2c/ihs_i2c.c
2129 - activate this driver with CONFIG_SYS_I2C_IHS
2130 - CONFIG_SYS_I2C_IHS_CH0 activate hardware channel 0
2131 - CONFIG_SYS_I2C_IHS_SPEED_0 speed channel 0
2132 - CONFIG_SYS_I2C_IHS_SLAVE_0 slave addr channel 0
2133 - CONFIG_SYS_I2C_IHS_CH1 activate hardware channel 1
2134 - CONFIG_SYS_I2C_IHS_SPEED_1 speed channel 1
2135 - CONFIG_SYS_I2C_IHS_SLAVE_1 slave addr channel 1
2136 - CONFIG_SYS_I2C_IHS_CH2 activate hardware channel 2
2137 - CONFIG_SYS_I2C_IHS_SPEED_2 speed channel 2
2138 - CONFIG_SYS_I2C_IHS_SLAVE_2 slave addr channel 2
2139 - CONFIG_SYS_I2C_IHS_CH3 activate hardware channel 3
2140 - CONFIG_SYS_I2C_IHS_SPEED_3 speed channel 3
2141 - CONFIG_SYS_I2C_IHS_SLAVE_3 slave addr channel 3
2142 - activate dual channel with CONFIG_SYS_I2C_IHS_DUAL
2143 - CONFIG_SYS_I2C_IHS_SPEED_0_1 speed channel 0_1
2144 - CONFIG_SYS_I2C_IHS_SLAVE_0_1 slave addr channel 0_1
2145 - CONFIG_SYS_I2C_IHS_SPEED_1_1 speed channel 1_1
2146 - CONFIG_SYS_I2C_IHS_SLAVE_1_1 slave addr channel 1_1
2147 - CONFIG_SYS_I2C_IHS_SPEED_2_1 speed channel 2_1
2148 - CONFIG_SYS_I2C_IHS_SLAVE_2_1 slave addr channel 2_1
2149 - CONFIG_SYS_I2C_IHS_SPEED_3_1 speed channel 3_1
2150 - CONFIG_SYS_I2C_IHS_SLAVE_3_1 slave addr channel 3_1
2154 CONFIG_SYS_NUM_I2C_BUSES
2155 Hold the number of i2c buses you want to use.
2157 CONFIG_SYS_I2C_DIRECT_BUS
2158 define this, if you don't use i2c muxes on your hardware.
2159 if CONFIG_SYS_I2C_MAX_HOPS is not defined or == 0 you can
2162 CONFIG_SYS_I2C_MAX_HOPS
2163 define how many muxes are maximal consecutively connected
2164 on one i2c bus. If you not use i2c muxes, omit this
2167 CONFIG_SYS_I2C_BUSES
2168 hold a list of buses you want to use, only used if
2169 CONFIG_SYS_I2C_DIRECT_BUS is not defined, for example
2170 a board with CONFIG_SYS_I2C_MAX_HOPS = 1 and
2171 CONFIG_SYS_NUM_I2C_BUSES = 9:
2173 CONFIG_SYS_I2C_BUSES {{0, {I2C_NULL_HOP}}, \
2174 {0, {{I2C_MUX_PCA9547, 0x70, 1}}}, \
2175 {0, {{I2C_MUX_PCA9547, 0x70, 2}}}, \
2176 {0, {{I2C_MUX_PCA9547, 0x70, 3}}}, \
2177 {0, {{I2C_MUX_PCA9547, 0x70, 4}}}, \
2178 {0, {{I2C_MUX_PCA9547, 0x70, 5}}}, \
2179 {1, {I2C_NULL_HOP}}, \
2180 {1, {{I2C_MUX_PCA9544, 0x72, 1}}}, \
2181 {1, {{I2C_MUX_PCA9544, 0x72, 2}}}, \
2185 bus 0 on adapter 0 without a mux
2186 bus 1 on adapter 0 with a PCA9547 on address 0x70 port 1
2187 bus 2 on adapter 0 with a PCA9547 on address 0x70 port 2
2188 bus 3 on adapter 0 with a PCA9547 on address 0x70 port 3
2189 bus 4 on adapter 0 with a PCA9547 on address 0x70 port 4
2190 bus 5 on adapter 0 with a PCA9547 on address 0x70 port 5
2191 bus 6 on adapter 1 without a mux
2192 bus 7 on adapter 1 with a PCA9544 on address 0x72 port 1
2193 bus 8 on adapter 1 with a PCA9544 on address 0x72 port 2
2195 If you do not have i2c muxes on your board, omit this define.
2197 - Legacy I2C Support:
2198 If you use the software i2c interface (CONFIG_SYS_I2C_SOFT)
2199 then the following macros need to be defined (examples are
2200 from include/configs/lwmon.h):
2204 (Optional). Any commands necessary to enable the I2C
2205 controller or configure ports.
2207 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
2211 (Only for MPC8260 CPU). The I/O port to use (the code
2212 assumes both bits are on the same port). Valid values
2213 are 0..3 for ports A..D.
2217 The code necessary to make the I2C data line active
2218 (driven). If the data line is open collector, this
2221 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
2225 The code necessary to make the I2C data line tri-stated
2226 (inactive). If the data line is open collector, this
2229 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
2233 Code that returns true if the I2C data line is high,
2236 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
2240 If <bit> is true, sets the I2C data line high. If it
2241 is false, it clears it (low).
2243 eg: #define I2C_SDA(bit) \
2244 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
2245 else immr->im_cpm.cp_pbdat &= ~PB_SDA
2249 If <bit> is true, sets the I2C clock line high. If it
2250 is false, it clears it (low).
2252 eg: #define I2C_SCL(bit) \
2253 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
2254 else immr->im_cpm.cp_pbdat &= ~PB_SCL
2258 This delay is invoked four times per clock cycle so this
2259 controls the rate of data transfer. The data rate thus
2260 is 1 / (I2C_DELAY * 4). Often defined to be something
2263 #define I2C_DELAY udelay(2)
2265 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
2267 If your arch supports the generic GPIO framework (asm/gpio.h),
2268 then you may alternatively define the two GPIOs that are to be
2269 used as SCL / SDA. Any of the previous I2C_xxx macros will
2270 have GPIO-based defaults assigned to them as appropriate.
2272 You should define these to the GPIO value as given directly to
2273 the generic GPIO functions.
2275 CONFIG_SYS_I2C_INIT_BOARD
2277 When a board is reset during an i2c bus transfer
2278 chips might think that the current transfer is still
2279 in progress. On some boards it is possible to access
2280 the i2c SCLK line directly, either by using the
2281 processor pin as a GPIO or by having a second pin
2282 connected to the bus. If this option is defined a
2283 custom i2c_init_board() routine in boards/xxx/board.c
2284 is run early in the boot sequence.
2286 CONFIG_I2C_MULTI_BUS
2288 This option allows the use of multiple I2C buses, each of which
2289 must have a controller. At any point in time, only one bus is
2290 active. To switch to a different bus, use the 'i2c dev' command.
2291 Note that bus numbering is zero-based.
2293 CONFIG_SYS_I2C_NOPROBES
2295 This option specifies a list of I2C devices that will be skipped
2296 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
2297 is set, specify a list of bus-device pairs. Otherwise, specify
2298 a 1D array of device addresses
2301 #undef CONFIG_I2C_MULTI_BUS
2302 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
2304 will skip addresses 0x50 and 0x68 on a board with one I2C bus
2306 #define CONFIG_I2C_MULTI_BUS
2307 #define CONFIG_SYS_I2C_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
2309 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
2311 CONFIG_SYS_SPD_BUS_NUM
2313 If defined, then this indicates the I2C bus number for DDR SPD.
2314 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
2316 CONFIG_SYS_RTC_BUS_NUM
2318 If defined, then this indicates the I2C bus number for the RTC.
2319 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
2321 CONFIG_SOFT_I2C_READ_REPEATED_START
2323 defining this will force the i2c_read() function in
2324 the soft_i2c driver to perform an I2C repeated start
2325 between writing the address pointer and reading the
2326 data. If this define is omitted the default behaviour
2327 of doing a stop-start sequence will be used. Most I2C
2328 devices can use either method, but some require one or
2331 - SPI Support: CONFIG_SPI
2333 Enables SPI driver (so far only tested with
2334 SPI EEPROM, also an instance works with Crystal A/D and
2335 D/As on the SACSng board)
2339 Enables the driver for SPI controller on SuperH. Currently
2340 only SH7757 is supported.
2344 Enables a software (bit-bang) SPI driver rather than
2345 using hardware support. This is a general purpose
2346 driver that only requires three general I/O port pins
2347 (two outputs, one input) to function. If this is
2348 defined, the board configuration must define several
2349 SPI configuration items (port pins to use, etc). For
2350 an example, see include/configs/sacsng.h.
2354 Enables a hardware SPI driver for general-purpose reads
2355 and writes. As with CONFIG_SOFT_SPI, the board configuration
2356 must define a list of chip-select function pointers.
2357 Currently supported on some MPC8xxx processors. For an
2358 example, see include/configs/mpc8349emds.h.
2362 Enables the driver for the SPI controllers on i.MX and MXC
2363 SoCs. Currently i.MX31/35/51 are supported.
2365 CONFIG_SYS_SPI_MXC_WAIT
2366 Timeout for waiting until spi transfer completed.
2367 default: (CONFIG_SYS_HZ/100) /* 10 ms */
2369 - FPGA Support: CONFIG_FPGA
2371 Enables FPGA subsystem.
2373 CONFIG_FPGA_<vendor>
2375 Enables support for specific chip vendors.
2378 CONFIG_FPGA_<family>
2380 Enables support for FPGA family.
2381 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
2385 Specify the number of FPGA devices to support.
2387 CONFIG_SYS_FPGA_PROG_FEEDBACK
2389 Enable printing of hash marks during FPGA configuration.
2391 CONFIG_SYS_FPGA_CHECK_BUSY
2393 Enable checks on FPGA configuration interface busy
2394 status by the configuration function. This option
2395 will require a board or device specific function to
2400 If defined, a function that provides delays in the FPGA
2401 configuration driver.
2403 CONFIG_SYS_FPGA_CHECK_CTRLC
2404 Allow Control-C to interrupt FPGA configuration
2406 CONFIG_SYS_FPGA_CHECK_ERROR
2408 Check for configuration errors during FPGA bitfile
2409 loading. For example, abort during Virtex II
2410 configuration if the INIT_B line goes low (which
2411 indicated a CRC error).
2413 CONFIG_SYS_FPGA_WAIT_INIT
2415 Maximum time to wait for the INIT_B line to de-assert
2416 after PROB_B has been de-asserted during a Virtex II
2417 FPGA configuration sequence. The default time is 500
2420 CONFIG_SYS_FPGA_WAIT_BUSY
2422 Maximum time to wait for BUSY to de-assert during
2423 Virtex II FPGA configuration. The default is 5 ms.
2425 CONFIG_SYS_FPGA_WAIT_CONFIG
2427 Time to wait after FPGA configuration. The default is
2430 - Configuration Management:
2433 Some SoCs need special image types (e.g. U-Boot binary
2434 with a special header) as build targets. By defining
2435 CONFIG_BUILD_TARGET in the SoC / board header, this
2436 special image will be automatically built upon calling
2441 If defined, this string will be added to the U-Boot
2442 version information (U_BOOT_VERSION)
2444 - Vendor Parameter Protection:
2446 U-Boot considers the values of the environment
2447 variables "serial#" (Board Serial Number) and
2448 "ethaddr" (Ethernet Address) to be parameters that
2449 are set once by the board vendor / manufacturer, and
2450 protects these variables from casual modification by
2451 the user. Once set, these variables are read-only,
2452 and write or delete attempts are rejected. You can
2453 change this behaviour:
2455 If CONFIG_ENV_OVERWRITE is #defined in your config
2456 file, the write protection for vendor parameters is
2457 completely disabled. Anybody can change or delete
2460 Alternatively, if you define _both_ an ethaddr in the
2461 default env _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2462 Ethernet address is installed in the environment,
2463 which can be changed exactly ONCE by the user. [The
2464 serial# is unaffected by this, i. e. it remains
2467 The same can be accomplished in a more flexible way
2468 for any variable by configuring the type of access
2469 to allow for those variables in the ".flags" variable
2470 or define CONFIG_ENV_FLAGS_LIST_STATIC.
2475 Define this variable to enable the reservation of
2476 "protected RAM", i. e. RAM which is not overwritten
2477 by U-Boot. Define CONFIG_PRAM to hold the number of
2478 kB you want to reserve for pRAM. You can overwrite
2479 this default value by defining an environment
2480 variable "pram" to the number of kB you want to
2481 reserve. Note that the board info structure will
2482 still show the full amount of RAM. If pRAM is
2483 reserved, a new environment variable "mem" will
2484 automatically be defined to hold the amount of
2485 remaining RAM in a form that can be passed as boot
2486 argument to Linux, for instance like that:
2488 setenv bootargs ... mem=\${mem}
2491 This way you can tell Linux not to use this memory,
2492 either, which results in a memory region that will
2493 not be affected by reboots.
2495 *WARNING* If your board configuration uses automatic
2496 detection of the RAM size, you must make sure that
2497 this memory test is non-destructive. So far, the
2498 following board configurations are known to be
2501 IVMS8, IVML24, SPD8xx, TQM8xxL,
2502 HERMES, IP860, RPXlite, LWMON,
2505 - Access to physical memory region (> 4GB)
2506 Some basic support is provided for operations on memory not
2507 normally accessible to U-Boot - e.g. some architectures
2508 support access to more than 4GB of memory on 32-bit
2509 machines using physical address extension or similar.
2510 Define CONFIG_PHYSMEM to access this basic support, which
2511 currently only supports clearing the memory.
2516 Define this variable to stop the system in case of a
2517 fatal error, so that you have to reset it manually.
2518 This is probably NOT a good idea for an embedded
2519 system where you want the system to reboot
2520 automatically as fast as possible, but it may be
2521 useful during development since you can try to debug
2522 the conditions that lead to the situation.
2524 CONFIG_NET_RETRY_COUNT
2526 This variable defines the number of retries for
2527 network operations like ARP, RARP, TFTP, or BOOTP
2528 before giving up the operation. If not defined, a
2529 default value of 5 is used.
2533 Timeout waiting for an ARP reply in milliseconds.
2537 Timeout in milliseconds used in NFS protocol.
2538 If you encounter "ERROR: Cannot umount" in nfs command,
2539 try longer timeout such as
2540 #define CONFIG_NFS_TIMEOUT 10000UL
2542 - Command Interpreter:
2543 CONFIG_AUTO_COMPLETE
2545 Enable auto completion of commands using TAB.
2547 CONFIG_SYS_PROMPT_HUSH_PS2
2549 This defines the secondary prompt string, which is
2550 printed when the command interpreter needs more input
2551 to complete a command. Usually "> ".
2555 In the current implementation, the local variables
2556 space and global environment variables space are
2557 separated. Local variables are those you define by
2558 simply typing `name=value'. To access a local
2559 variable later on, you have write `$name' or
2560 `${name}'; to execute the contents of a variable
2561 directly type `$name' at the command prompt.
2563 Global environment variables are those you use
2564 setenv/printenv to work with. To run a command stored
2565 in such a variable, you need to use the run command,
2566 and you must not use the '$' sign to access them.
2568 To store commands and special characters in a
2569 variable, please use double quotation marks
2570 surrounding the whole text of the variable, instead
2571 of the backslashes before semicolons and special
2574 - Command Line Editing and History:
2575 CONFIG_CMDLINE_EDITING
2577 Enable editing and History functions for interactive
2578 command line input operations
2580 - Command Line PS1/PS2 support:
2581 CONFIG_CMDLINE_PS_SUPPORT
2583 Enable support for changing the command prompt string
2584 at run-time. Only static string is supported so far.
2585 The string is obtained from environment variables PS1
2588 - Default Environment:
2589 CONFIG_EXTRA_ENV_SETTINGS
2591 Define this to contain any number of null terminated
2592 strings (variable = value pairs) that will be part of
2593 the default environment compiled into the boot image.
2595 For example, place something like this in your
2596 board's config file:
2598 #define CONFIG_EXTRA_ENV_SETTINGS \
2602 Warning: This method is based on knowledge about the
2603 internal format how the environment is stored by the
2604 U-Boot code. This is NOT an official, exported
2605 interface! Although it is unlikely that this format
2606 will change soon, there is no guarantee either.
2607 You better know what you are doing here.
2609 Note: overly (ab)use of the default environment is
2610 discouraged. Make sure to check other ways to preset
2611 the environment like the "source" command or the
2614 CONFIG_ENV_VARS_UBOOT_CONFIG
2616 Define this in order to add variables describing the
2617 U-Boot build configuration to the default environment.
2618 These will be named arch, cpu, board, vendor, and soc.
2620 Enabling this option will cause the following to be defined:
2628 CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG
2630 Define this in order to add variables describing certain
2631 run-time determined information about the hardware to the
2632 environment. These will be named board_name, board_rev.
2634 CONFIG_DELAY_ENVIRONMENT
2636 Normally the environment is loaded when the board is
2637 initialised so that it is available to U-Boot. This inhibits
2638 that so that the environment is not available until
2639 explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL
2640 this is instead controlled by the value of
2641 /config/load-environment.
2643 - DataFlash Support:
2644 CONFIG_HAS_DATAFLASH
2646 Defining this option enables DataFlash features and
2647 allows to read/write in Dataflash via the standard
2650 - Serial Flash support
2653 Defining this option enables SPI flash commands
2654 'sf probe/read/write/erase/update'.
2656 Usage requires an initial 'probe' to define the serial
2657 flash parameters, followed by read/write/erase/update
2660 The following defaults may be provided by the platform
2661 to handle the common case when only a single serial
2662 flash is present on the system.
2664 CONFIG_SF_DEFAULT_BUS Bus identifier
2665 CONFIG_SF_DEFAULT_CS Chip-select
2666 CONFIG_SF_DEFAULT_MODE (see include/spi.h)
2667 CONFIG_SF_DEFAULT_SPEED in Hz
2671 Define this option to include a destructive SPI flash
2674 CONFIG_SF_DUAL_FLASH Dual flash memories
2676 Define this option to use dual flash support where two flash
2677 memories can be connected with a given cs line.
2678 Currently Xilinx Zynq qspi supports these type of connections.
2680 - SystemACE Support:
2683 Adding this option adds support for Xilinx SystemACE
2684 chips attached via some sort of local bus. The address
2685 of the chip must also be defined in the
2686 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
2688 #define CONFIG_SYSTEMACE
2689 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
2691 When SystemACE support is added, the "ace" device type
2692 becomes available to the fat commands, i.e. fatls.
2694 - TFTP Fixed UDP Port:
2697 If this is defined, the environment variable tftpsrcp
2698 is used to supply the TFTP UDP source port value.
2699 If tftpsrcp isn't defined, the normal pseudo-random port
2700 number generator is used.
2702 Also, the environment variable tftpdstp is used to supply
2703 the TFTP UDP destination port value. If tftpdstp isn't
2704 defined, the normal port 69 is used.
2706 The purpose for tftpsrcp is to allow a TFTP server to
2707 blindly start the TFTP transfer using the pre-configured
2708 target IP address and UDP port. This has the effect of
2709 "punching through" the (Windows XP) firewall, allowing
2710 the remainder of the TFTP transfer to proceed normally.
2711 A better solution is to properly configure the firewall,
2712 but sometimes that is not allowed.
2717 This enables a generic 'hash' command which can produce
2718 hashes / digests from a few algorithms (e.g. SHA1, SHA256).
2722 Enable the hash verify command (hash -v). This adds to code
2725 Note: There is also a sha1sum command, which should perhaps
2726 be deprecated in favour of 'hash sha1'.
2728 - Freescale i.MX specific commands:
2729 CONFIG_CMD_HDMIDETECT
2730 This enables 'hdmidet' command which returns true if an
2731 HDMI monitor is detected. This command is i.MX 6 specific.
2733 - bootcount support:
2734 CONFIG_BOOTCOUNT_LIMIT
2736 This enables the bootcounter support, see:
2737 http://www.denx.de/wiki/DULG/UBootBootCountLimit
2740 enable special bootcounter support on at91sam9xe based boards.
2742 enable special bootcounter support on da850 based boards.
2743 CONFIG_BOOTCOUNT_RAM
2744 enable support for the bootcounter in RAM
2745 CONFIG_BOOTCOUNT_I2C
2746 enable support for the bootcounter on an i2c (like RTC) device.
2747 CONFIG_SYS_I2C_RTC_ADDR = i2c chip address
2748 CONFIG_SYS_BOOTCOUNT_ADDR = i2c addr which is used for
2750 CONFIG_BOOTCOUNT_ALEN = address len
2752 - Show boot progress:
2753 CONFIG_SHOW_BOOT_PROGRESS
2755 Defining this option allows to add some board-
2756 specific code (calling a user-provided function
2757 "show_boot_progress(int)") that enables you to show
2758 the system's boot progress on some display (for
2759 example, some LED's) on your board. At the moment,
2760 the following checkpoints are implemented:
2763 Legacy uImage format:
2766 1 common/cmd_bootm.c before attempting to boot an image
2767 -1 common/cmd_bootm.c Image header has bad magic number
2768 2 common/cmd_bootm.c Image header has correct magic number
2769 -2 common/cmd_bootm.c Image header has bad checksum
2770 3 common/cmd_bootm.c Image header has correct checksum
2771 -3 common/cmd_bootm.c Image data has bad checksum
2772 4 common/cmd_bootm.c Image data has correct checksum
2773 -4 common/cmd_bootm.c Image is for unsupported architecture
2774 5 common/cmd_bootm.c Architecture check OK
2775 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
2776 6 common/cmd_bootm.c Image Type check OK
2777 -6 common/cmd_bootm.c gunzip uncompression error
2778 -7 common/cmd_bootm.c Unimplemented compression type
2779 7 common/cmd_bootm.c Uncompression OK
2780 8 common/cmd_bootm.c No uncompress/copy overwrite error
2781 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
2783 9 common/image.c Start initial ramdisk verification
2784 -10 common/image.c Ramdisk header has bad magic number
2785 -11 common/image.c Ramdisk header has bad checksum
2786 10 common/image.c Ramdisk header is OK
2787 -12 common/image.c Ramdisk data has bad checksum
2788 11 common/image.c Ramdisk data has correct checksum
2789 12 common/image.c Ramdisk verification complete, start loading
2790 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
2791 13 common/image.c Start multifile image verification
2792 14 common/image.c No initial ramdisk, no multifile, continue.
2794 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
2796 -30 arch/powerpc/lib/board.c Fatal error, hang the system
2797 -31 post/post.c POST test failed, detected by post_output_backlog()
2798 -32 post/post.c POST test failed, detected by post_run_single()
2800 34 common/cmd_doc.c before loading a Image from a DOC device
2801 -35 common/cmd_doc.c Bad usage of "doc" command
2802 35 common/cmd_doc.c correct usage of "doc" command
2803 -36 common/cmd_doc.c No boot device
2804 36 common/cmd_doc.c correct boot device
2805 -37 common/cmd_doc.c Unknown Chip ID on boot device
2806 37 common/cmd_doc.c correct chip ID found, device available
2807 -38 common/cmd_doc.c Read Error on boot device
2808 38 common/cmd_doc.c reading Image header from DOC device OK
2809 -39 common/cmd_doc.c Image header has bad magic number
2810 39 common/cmd_doc.c Image header has correct magic number
2811 -40 common/cmd_doc.c Error reading Image from DOC device
2812 40 common/cmd_doc.c Image header has correct magic number
2813 41 common/cmd_ide.c before loading a Image from a IDE device
2814 -42 common/cmd_ide.c Bad usage of "ide" command
2815 42 common/cmd_ide.c correct usage of "ide" command
2816 -43 common/cmd_ide.c No boot device
2817 43 common/cmd_ide.c boot device found
2818 -44 common/cmd_ide.c Device not available
2819 44 common/cmd_ide.c Device available
2820 -45 common/cmd_ide.c wrong partition selected
2821 45 common/cmd_ide.c partition selected
2822 -46 common/cmd_ide.c Unknown partition table
2823 46 common/cmd_ide.c valid partition table found
2824 -47 common/cmd_ide.c Invalid partition type
2825 47 common/cmd_ide.c correct partition type
2826 -48 common/cmd_ide.c Error reading Image Header on boot device
2827 48 common/cmd_ide.c reading Image Header from IDE device OK
2828 -49 common/cmd_ide.c Image header has bad magic number
2829 49 common/cmd_ide.c Image header has correct magic number
2830 -50 common/cmd_ide.c Image header has bad checksum
2831 50 common/cmd_ide.c Image header has correct checksum
2832 -51 common/cmd_ide.c Error reading Image from IDE device
2833 51 common/cmd_ide.c reading Image from IDE device OK
2834 52 common/cmd_nand.c before loading a Image from a NAND device
2835 -53 common/cmd_nand.c Bad usage of "nand" command
2836 53 common/cmd_nand.c correct usage of "nand" command
2837 -54 common/cmd_nand.c No boot device
2838 54 common/cmd_nand.c boot device found
2839 -55 common/cmd_nand.c Unknown Chip ID on boot device
2840 55 common/cmd_nand.c correct chip ID found, device available
2841 -56 common/cmd_nand.c Error reading Image Header on boot device
2842 56 common/cmd_nand.c reading Image Header from NAND device OK
2843 -57 common/cmd_nand.c Image header has bad magic number
2844 57 common/cmd_nand.c Image header has correct magic number
2845 -58 common/cmd_nand.c Error reading Image from NAND device
2846 58 common/cmd_nand.c reading Image from NAND device OK
2848 -60 common/env_common.c Environment has a bad CRC, using default
2850 64 net/eth.c starting with Ethernet configuration.
2851 -64 net/eth.c no Ethernet found.
2852 65 net/eth.c Ethernet found.
2854 -80 common/cmd_net.c usage wrong
2855 80 common/cmd_net.c before calling net_loop()
2856 -81 common/cmd_net.c some error in net_loop() occurred
2857 81 common/cmd_net.c net_loop() back without error
2858 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
2859 82 common/cmd_net.c trying automatic boot
2860 83 common/cmd_net.c running "source" command
2861 -83 common/cmd_net.c some error in automatic boot or "source" command
2862 84 common/cmd_net.c end without errors
2867 100 common/cmd_bootm.c Kernel FIT Image has correct format
2868 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
2869 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
2870 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
2871 102 common/cmd_bootm.c Kernel unit name specified
2872 -103 common/cmd_bootm.c Can't get kernel subimage node offset
2873 103 common/cmd_bootm.c Found configuration node
2874 104 common/cmd_bootm.c Got kernel subimage node offset
2875 -104 common/cmd_bootm.c Kernel subimage hash verification failed
2876 105 common/cmd_bootm.c Kernel subimage hash verification OK
2877 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
2878 106 common/cmd_bootm.c Architecture check OK
2879 -106 common/cmd_bootm.c Kernel subimage has wrong type
2880 107 common/cmd_bootm.c Kernel subimage type OK
2881 -107 common/cmd_bootm.c Can't get kernel subimage data/size
2882 108 common/cmd_bootm.c Got kernel subimage data/size
2883 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
2884 -109 common/cmd_bootm.c Can't get kernel subimage type
2885 -110 common/cmd_bootm.c Can't get kernel subimage comp
2886 -111 common/cmd_bootm.c Can't get kernel subimage os
2887 -112 common/cmd_bootm.c Can't get kernel subimage load address
2888 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
2890 120 common/image.c Start initial ramdisk verification
2891 -120 common/image.c Ramdisk FIT image has incorrect format
2892 121 common/image.c Ramdisk FIT image has correct format
2893 122 common/image.c No ramdisk subimage unit name, using configuration
2894 -122 common/image.c Can't get configuration for ramdisk subimage
2895 123 common/image.c Ramdisk unit name specified
2896 -124 common/image.c Can't get ramdisk subimage node offset
2897 125 common/image.c Got ramdisk subimage node offset
2898 -125 common/image.c Ramdisk subimage hash verification failed
2899 126 common/image.c Ramdisk subimage hash verification OK
2900 -126 common/image.c Ramdisk subimage for unsupported architecture
2901 127 common/image.c Architecture check OK
2902 -127 common/image.c Can't get ramdisk subimage data/size
2903 128 common/image.c Got ramdisk subimage data/size
2904 129 common/image.c Can't get ramdisk load address
2905 -129 common/image.c Got ramdisk load address
2907 -130 common/cmd_doc.c Incorrect FIT image format
2908 131 common/cmd_doc.c FIT image format OK
2910 -140 common/cmd_ide.c Incorrect FIT image format
2911 141 common/cmd_ide.c FIT image format OK
2913 -150 common/cmd_nand.c Incorrect FIT image format
2914 151 common/cmd_nand.c FIT image format OK
2916 - legacy image format:
2917 CONFIG_IMAGE_FORMAT_LEGACY
2918 enables the legacy image format support in U-Boot.
2921 enabled if CONFIG_FIT_SIGNATURE is not defined.
2923 CONFIG_DISABLE_IMAGE_LEGACY
2924 disable the legacy image format
2926 This define is introduced, as the legacy image format is
2927 enabled per default for backward compatibility.
2929 - Standalone program support:
2930 CONFIG_STANDALONE_LOAD_ADDR
2932 This option defines a board specific value for the
2933 address where standalone program gets loaded, thus
2934 overwriting the architecture dependent default
2937 - Frame Buffer Address:
2940 Define CONFIG_FB_ADDR if you want to use specific
2941 address for frame buffer. This is typically the case
2942 when using a graphics controller has separate video
2943 memory. U-Boot will then place the frame buffer at
2944 the given address instead of dynamically reserving it
2945 in system RAM by calling lcd_setmem(), which grabs
2946 the memory for the frame buffer depending on the
2947 configured panel size.
2949 Please see board_init_f function.
2951 - Automatic software updates via TFTP server
2953 CONFIG_UPDATE_TFTP_CNT_MAX
2954 CONFIG_UPDATE_TFTP_MSEC_MAX
2956 These options enable and control the auto-update feature;
2957 for a more detailed description refer to doc/README.update.
2959 - MTD Support (mtdparts command, UBI support)
2962 Adds the MTD device infrastructure from the Linux kernel.
2963 Needed for mtdparts command support.
2965 CONFIG_MTD_PARTITIONS
2967 Adds the MTD partitioning infrastructure from the Linux
2968 kernel. Needed for UBI support.
2973 Adds commands for interacting with MTD partitions formatted
2974 with the UBI flash translation layer
2976 Requires also defining CONFIG_RBTREE
2978 CONFIG_UBI_SILENCE_MSG
2980 Make the verbose messages from UBI stop printing. This leaves
2981 warnings and errors enabled.
2984 CONFIG_MTD_UBI_WL_THRESHOLD
2985 This parameter defines the maximum difference between the highest
2986 erase counter value and the lowest erase counter value of eraseblocks
2987 of UBI devices. When this threshold is exceeded, UBI starts performing
2988 wear leveling by means of moving data from eraseblock with low erase
2989 counter to eraseblocks with high erase counter.
2991 The default value should be OK for SLC NAND flashes, NOR flashes and
2992 other flashes which have eraseblock life-cycle 100000 or more.
2993 However, in case of MLC NAND flashes which typically have eraseblock
2994 life-cycle less than 10000, the threshold should be lessened (e.g.,
2995 to 128 or 256, although it does not have to be power of 2).
2999 CONFIG_MTD_UBI_BEB_LIMIT
3000 This option specifies the maximum bad physical eraseblocks UBI
3001 expects on the MTD device (per 1024 eraseblocks). If the
3002 underlying flash does not admit of bad eraseblocks (e.g. NOR
3003 flash), this value is ignored.
3005 NAND datasheets often specify the minimum and maximum NVM
3006 (Number of Valid Blocks) for the flashes' endurance lifetime.
3007 The maximum expected bad eraseblocks per 1024 eraseblocks
3008 then can be calculated as "1024 * (1 - MinNVB / MaxNVB)",
3009 which gives 20 for most NANDs (MaxNVB is basically the total
3010 count of eraseblocks on the chip).
3012 To put it differently, if this value is 20, UBI will try to
3013 reserve about 1.9% of physical eraseblocks for bad blocks
3014 handling. And that will be 1.9% of eraseblocks on the entire
3015 NAND chip, not just the MTD partition UBI attaches. This means
3016 that if you have, say, a NAND flash chip admits maximum 40 bad
3017 eraseblocks, and it is split on two MTD partitions of the same
3018 size, UBI will reserve 40 eraseblocks when attaching a
3023 CONFIG_MTD_UBI_FASTMAP
3024 Fastmap is a mechanism which allows attaching an UBI device
3025 in nearly constant time. Instead of scanning the whole MTD device it
3026 only has to locate a checkpoint (called fastmap) on the device.
3027 The on-flash fastmap contains all information needed to attach
3028 the device. Using fastmap makes only sense on large devices where
3029 attaching by scanning takes long. UBI will not automatically install
3030 a fastmap on old images, but you can set the UBI parameter
3031 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT to 1 if you want so. Please note
3032 that fastmap-enabled images are still usable with UBI implementations
3033 without fastmap support. On typical flash devices the whole fastmap
3034 fits into one PEB. UBI will reserve PEBs to hold two fastmaps.
3036 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT
3037 Set this parameter to enable fastmap automatically on images
3041 CONFIG_MTD_UBI_FM_DEBUG
3042 Enable UBI fastmap debug
3048 Adds commands for interacting with UBI volumes formatted as
3049 UBIFS. UBIFS is read-only in u-boot.
3051 Requires UBI support as well as CONFIG_LZO
3053 CONFIG_UBIFS_SILENCE_MSG
3055 Make the verbose messages from UBIFS stop printing. This leaves
3056 warnings and errors enabled.
3060 Enable building of SPL globally.
3063 LDSCRIPT for linking the SPL binary.
3065 CONFIG_SPL_MAX_FOOTPRINT
3066 Maximum size in memory allocated to the SPL, BSS included.
3067 When defined, the linker checks that the actual memory
3068 used by SPL from _start to __bss_end does not exceed it.
3069 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3070 must not be both defined at the same time.
3073 Maximum size of the SPL image (text, data, rodata, and
3074 linker lists sections), BSS excluded.
3075 When defined, the linker checks that the actual size does
3078 CONFIG_SPL_TEXT_BASE
3079 TEXT_BASE for linking the SPL binary.
3081 CONFIG_SPL_RELOC_TEXT_BASE
3082 Address to relocate to. If unspecified, this is equal to
3083 CONFIG_SPL_TEXT_BASE (i.e. no relocation is done).
3085 CONFIG_SPL_BSS_START_ADDR
3086 Link address for the BSS within the SPL binary.
3088 CONFIG_SPL_BSS_MAX_SIZE
3089 Maximum size in memory allocated to the SPL BSS.
3090 When defined, the linker checks that the actual memory used
3091 by SPL from __bss_start to __bss_end does not exceed it.
3092 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3093 must not be both defined at the same time.
3096 Adress of the start of the stack SPL will use
3098 CONFIG_SPL_PANIC_ON_RAW_IMAGE
3099 When defined, SPL will panic() if the image it has
3100 loaded does not have a signature.
3101 Defining this is useful when code which loads images
3102 in SPL cannot guarantee that absolutely all read errors
3104 An example is the LPC32XX MLC NAND driver, which will
3105 consider that a completely unreadable NAND block is bad,
3106 and thus should be skipped silently.
3108 CONFIG_SPL_RELOC_STACK
3109 Adress of the start of the stack SPL will use after
3110 relocation. If unspecified, this is equal to
3113 CONFIG_SYS_SPL_MALLOC_START
3114 Starting address of the malloc pool used in SPL.
3115 When this option is set the full malloc is used in SPL and
3116 it is set up by spl_init() and before that, the simple malloc()
3117 can be used if CONFIG_SYS_MALLOC_F is defined.
3119 CONFIG_SYS_SPL_MALLOC_SIZE
3120 The size of the malloc pool used in SPL.
3122 CONFIG_SPL_FRAMEWORK
3123 Enable the SPL framework under common/. This framework
3124 supports MMC, NAND and YMODEM loading of U-Boot and NAND
3125 NAND loading of the Linux Kernel.
3128 Enable booting directly to an OS from SPL.
3129 See also: doc/README.falcon
3131 CONFIG_SPL_DISPLAY_PRINT
3132 For ARM, enable an optional function to print more information
3133 about the running system.
3135 CONFIG_SPL_INIT_MINIMAL
3136 Arch init code should be built for a very small image
3138 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_PARTITION
3139 Partition on the MMC to load U-Boot from when the MMC is being
3142 CONFIG_SYS_MMCSD_RAW_MODE_KERNEL_SECTOR
3143 Sector to load kernel uImage from when MMC is being
3144 used in raw mode (for Falcon mode)
3146 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTOR,
3147 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTORS
3148 Sector and number of sectors to load kernel argument
3149 parameters from when MMC is being used in raw mode
3152 CONFIG_SYS_MMCSD_FS_BOOT_PARTITION
3153 Partition on the MMC to load U-Boot from when the MMC is being
3156 CONFIG_SPL_FS_LOAD_PAYLOAD_NAME
3157 Filename to read to load U-Boot when reading from filesystem
3159 CONFIG_SPL_FS_LOAD_KERNEL_NAME
3160 Filename to read to load kernel uImage when reading
3161 from filesystem (for Falcon mode)
3163 CONFIG_SPL_FS_LOAD_ARGS_NAME
3164 Filename to read to load kernel argument parameters
3165 when reading from filesystem (for Falcon mode)
3167 CONFIG_SPL_MPC83XX_WAIT_FOR_NAND
3168 Set this for NAND SPL on PPC mpc83xx targets, so that
3169 start.S waits for the rest of the SPL to load before
3170 continuing (the hardware starts execution after just
3171 loading the first page rather than the full 4K).
3173 CONFIG_SPL_SKIP_RELOCATE
3174 Avoid SPL relocation
3176 CONFIG_SPL_NAND_BASE
3177 Include nand_base.c in the SPL. Requires
3178 CONFIG_SPL_NAND_DRIVERS.
3180 CONFIG_SPL_NAND_DRIVERS
3181 SPL uses normal NAND drivers, not minimal drivers.
3184 Include standard software ECC in the SPL
3186 CONFIG_SPL_NAND_SIMPLE
3187 Support for NAND boot using simple NAND drivers that
3188 expose the cmd_ctrl() interface.
3191 Support for a lightweight UBI (fastmap) scanner and
3194 CONFIG_SPL_NAND_RAW_ONLY
3195 Support to boot only raw u-boot.bin images. Use this only
3196 if you need to save space.
3198 CONFIG_SPL_COMMON_INIT_DDR
3199 Set for common ddr init with serial presence detect in
3202 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
3203 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
3204 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
3205 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
3206 CONFIG_SYS_NAND_ECCBYTES
3207 Defines the size and behavior of the NAND that SPL uses
3210 CONFIG_SPL_NAND_BOOT
3211 Add support NAND boot
3213 CONFIG_SYS_NAND_U_BOOT_OFFS
3214 Location in NAND to read U-Boot from
3216 CONFIG_SYS_NAND_U_BOOT_DST
3217 Location in memory to load U-Boot to
3219 CONFIG_SYS_NAND_U_BOOT_SIZE
3220 Size of image to load
3222 CONFIG_SYS_NAND_U_BOOT_START
3223 Entry point in loaded image to jump to
3225 CONFIG_SYS_NAND_HW_ECC_OOBFIRST
3226 Define this if you need to first read the OOB and then the
3227 data. This is used, for example, on davinci platforms.
3229 CONFIG_SPL_OMAP3_ID_NAND
3230 Support for an OMAP3-specific set of functions to return the
3231 ID and MFR of the first attached NAND chip, if present.
3233 CONFIG_SPL_RAM_DEVICE
3234 Support for running image already present in ram, in SPL binary
3237 Image offset to which the SPL should be padded before appending
3238 the SPL payload. By default, this is defined as
3239 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3240 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3241 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3244 Final target image containing SPL and payload. Some SPLs
3245 use an arch-specific makefile fragment instead, for
3246 example if more than one image needs to be produced.
3248 CONFIG_FIT_SPL_PRINT
3249 Printing information about a FIT image adds quite a bit of
3250 code to SPL. So this is normally disabled in SPL. Use this
3251 option to re-enable it. This will affect the output of the
3252 bootm command when booting a FIT image.
3256 Enable building of TPL globally.
3259 Image offset to which the TPL should be padded before appending
3260 the TPL payload. By default, this is defined as
3261 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3262 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3263 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3265 - Interrupt support (PPC):
3267 There are common interrupt_init() and timer_interrupt()
3268 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
3269 for CPU specific initialization. interrupt_init_cpu()
3270 should set decrementer_count to appropriate value. If
3271 CPU resets decrementer automatically after interrupt
3272 (ppc4xx) it should set decrementer_count to zero.
3273 timer_interrupt() calls timer_interrupt_cpu() for CPU
3274 specific handling. If board has watchdog / status_led
3275 / other_activity_monitor it works automatically from
3276 general timer_interrupt().
3279 Board initialization settings:
3280 ------------------------------
3282 During Initialization u-boot calls a number of board specific functions
3283 to allow the preparation of board specific prerequisites, e.g. pin setup
3284 before drivers are initialized. To enable these callbacks the
3285 following configuration macros have to be defined. Currently this is
3286 architecture specific, so please check arch/your_architecture/lib/board.c
3287 typically in board_init_f() and board_init_r().
3289 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
3290 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
3291 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
3292 - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
3294 Configuration Settings:
3295 -----------------------
3297 - CONFIG_SYS_SUPPORT_64BIT_DATA: Defined automatically if compiled as 64-bit.
3298 Optionally it can be defined to support 64-bit memory commands.
3300 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
3301 undefine this when you're short of memory.
3303 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
3304 width of the commands listed in the 'help' command output.
3306 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
3307 prompt for user input.
3309 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
3311 - CONFIG_SYS_PBSIZE: Buffer size for Console output
3313 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
3315 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
3316 the application (usually a Linux kernel) when it is
3319 - CONFIG_SYS_BAUDRATE_TABLE:
3320 List of legal baudrate settings for this board.
3322 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
3323 Begin and End addresses of the area used by the
3326 - CONFIG_SYS_ALT_MEMTEST:
3327 Enable an alternate, more extensive memory test.
3329 - CONFIG_SYS_MEMTEST_SCRATCH:
3330 Scratch address used by the alternate memory test
3331 You only need to set this if address zero isn't writeable
3333 - CONFIG_SYS_MEM_RESERVE_SECURE
3334 Only implemented for ARMv8 for now.
3335 If defined, the size of CONFIG_SYS_MEM_RESERVE_SECURE memory
3336 is substracted from total RAM and won't be reported to OS.
3337 This memory can be used as secure memory. A variable
3338 gd->arch.secure_ram is used to track the location. In systems
3339 the RAM base is not zero, or RAM is divided into banks,
3340 this variable needs to be recalcuated to get the address.
3342 - CONFIG_SYS_MEM_TOP_HIDE:
3343 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
3344 this specified memory area will get subtracted from the top
3345 (end) of RAM and won't get "touched" at all by U-Boot. By
3346 fixing up gd->ram_size the Linux kernel should gets passed
3347 the now "corrected" memory size and won't touch it either.
3348 This should work for arch/ppc and arch/powerpc. Only Linux
3349 board ports in arch/powerpc with bootwrapper support that
3350 recalculate the memory size from the SDRAM controller setup
3351 will have to get fixed in Linux additionally.
3353 This option can be used as a workaround for the 440EPx/GRx
3354 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
3357 WARNING: Please make sure that this value is a multiple of
3358 the Linux page size (normally 4k). If this is not the case,
3359 then the end address of the Linux memory will be located at a
3360 non page size aligned address and this could cause major
3363 - CONFIG_SYS_LOADS_BAUD_CHANGE:
3364 Enable temporary baudrate change while serial download
3366 - CONFIG_SYS_SDRAM_BASE:
3367 Physical start address of SDRAM. _Must_ be 0 here.
3369 - CONFIG_SYS_FLASH_BASE:
3370 Physical start address of Flash memory.
3372 - CONFIG_SYS_MONITOR_BASE:
3373 Physical start address of boot monitor code (set by
3374 make config files to be same as the text base address
3375 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
3376 CONFIG_SYS_FLASH_BASE when booting from flash.
3378 - CONFIG_SYS_MONITOR_LEN:
3379 Size of memory reserved for monitor code, used to
3380 determine _at_compile_time_ (!) if the environment is
3381 embedded within the U-Boot image, or in a separate
3384 - CONFIG_SYS_MALLOC_LEN:
3385 Size of DRAM reserved for malloc() use.
3387 - CONFIG_SYS_MALLOC_F_LEN
3388 Size of the malloc() pool for use before relocation. If
3389 this is defined, then a very simple malloc() implementation
3390 will become available before relocation. The address is just
3391 below the global data, and the stack is moved down to make
3394 This feature allocates regions with increasing addresses
3395 within the region. calloc() is supported, but realloc()
3396 is not available. free() is supported but does nothing.
3397 The memory will be freed (or in fact just forgotten) when
3398 U-Boot relocates itself.
3400 - CONFIG_SYS_MALLOC_SIMPLE
3401 Provides a simple and small malloc() and calloc() for those
3402 boards which do not use the full malloc in SPL (which is
3403 enabled with CONFIG_SYS_SPL_MALLOC_START).
3405 - CONFIG_SYS_NONCACHED_MEMORY:
3406 Size of non-cached memory area. This area of memory will be
3407 typically located right below the malloc() area and mapped
3408 uncached in the MMU. This is useful for drivers that would
3409 otherwise require a lot of explicit cache maintenance. For
3410 some drivers it's also impossible to properly maintain the
3411 cache. For example if the regions that need to be flushed
3412 are not a multiple of the cache-line size, *and* padding
3413 cannot be allocated between the regions to align them (i.e.
3414 if the HW requires a contiguous array of regions, and the
3415 size of each region is not cache-aligned), then a flush of
3416 one region may result in overwriting data that hardware has
3417 written to another region in the same cache-line. This can
3418 happen for example in network drivers where descriptors for
3419 buffers are typically smaller than the CPU cache-line (e.g.
3420 16 bytes vs. 32 or 64 bytes).
3422 Non-cached memory is only supported on 32-bit ARM at present.
3424 - CONFIG_SYS_BOOTM_LEN:
3425 Normally compressed uImages are limited to an
3426 uncompressed size of 8 MBytes. If this is not enough,
3427 you can define CONFIG_SYS_BOOTM_LEN in your board config file
3428 to adjust this setting to your needs.
3430 - CONFIG_SYS_BOOTMAPSZ:
3431 Maximum size of memory mapped by the startup code of
3432 the Linux kernel; all data that must be processed by
3433 the Linux kernel (bd_info, boot arguments, FDT blob if
3434 used) must be put below this limit, unless "bootm_low"
3435 environment variable is defined and non-zero. In such case
3436 all data for the Linux kernel must be between "bootm_low"
3437 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
3438 variable "bootm_mapsize" will override the value of
3439 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
3440 then the value in "bootm_size" will be used instead.
3442 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
3443 Enable initrd_high functionality. If defined then the
3444 initrd_high feature is enabled and the bootm ramdisk subcommand
3447 - CONFIG_SYS_BOOT_GET_CMDLINE:
3448 Enables allocating and saving kernel cmdline in space between
3449 "bootm_low" and "bootm_low" + BOOTMAPSZ.
3451 - CONFIG_SYS_BOOT_GET_KBD:
3452 Enables allocating and saving a kernel copy of the bd_info in
3453 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
3455 - CONFIG_SYS_MAX_FLASH_BANKS:
3456 Max number of Flash memory banks
3458 - CONFIG_SYS_MAX_FLASH_SECT:
3459 Max number of sectors on a Flash chip
3461 - CONFIG_SYS_FLASH_ERASE_TOUT:
3462 Timeout for Flash erase operations (in ms)
3464 - CONFIG_SYS_FLASH_WRITE_TOUT:
3465 Timeout for Flash write operations (in ms)
3467 - CONFIG_SYS_FLASH_LOCK_TOUT
3468 Timeout for Flash set sector lock bit operation (in ms)
3470 - CONFIG_SYS_FLASH_UNLOCK_TOUT
3471 Timeout for Flash clear lock bits operation (in ms)
3473 - CONFIG_SYS_FLASH_PROTECTION
3474 If defined, hardware flash sectors protection is used
3475 instead of U-Boot software protection.
3477 - CONFIG_SYS_DIRECT_FLASH_TFTP:
3479 Enable TFTP transfers directly to flash memory;
3480 without this option such a download has to be
3481 performed in two steps: (1) download to RAM, and (2)
3482 copy from RAM to flash.
3484 The two-step approach is usually more reliable, since
3485 you can check if the download worked before you erase
3486 the flash, but in some situations (when system RAM is
3487 too limited to allow for a temporary copy of the
3488 downloaded image) this option may be very useful.
3490 - CONFIG_SYS_FLASH_CFI:
3491 Define if the flash driver uses extra elements in the
3492 common flash structure for storing flash geometry.
3494 - CONFIG_FLASH_CFI_DRIVER
3495 This option also enables the building of the cfi_flash driver
3496 in the drivers directory
3498 - CONFIG_FLASH_CFI_MTD
3499 This option enables the building of the cfi_mtd driver
3500 in the drivers directory. The driver exports CFI flash
3503 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
3504 Use buffered writes to flash.
3506 - CONFIG_FLASH_SPANSION_S29WS_N
3507 s29ws-n MirrorBit flash has non-standard addresses for buffered
3510 - CONFIG_SYS_FLASH_QUIET_TEST
3511 If this option is defined, the common CFI flash doesn't
3512 print it's warning upon not recognized FLASH banks. This
3513 is useful, if some of the configured banks are only
3514 optionally available.
3516 - CONFIG_FLASH_SHOW_PROGRESS
3517 If defined (must be an integer), print out countdown
3518 digits and dots. Recommended value: 45 (9..1) for 80
3519 column displays, 15 (3..1) for 40 column displays.
3521 - CONFIG_FLASH_VERIFY
3522 If defined, the content of the flash (destination) is compared
3523 against the source after the write operation. An error message
3524 will be printed when the contents are not identical.
3525 Please note that this option is useless in nearly all cases,
3526 since such flash programming errors usually are detected earlier
3527 while unprotecting/erasing/programming. Please only enable
3528 this option if you really know what you are doing.
3530 - CONFIG_SYS_RX_ETH_BUFFER:
3531 Defines the number of Ethernet receive buffers. On some
3532 Ethernet controllers it is recommended to set this value
3533 to 8 or even higher (EEPRO100 or 405 EMAC), since all
3534 buffers can be full shortly after enabling the interface
3535 on high Ethernet traffic.
3536 Defaults to 4 if not defined.
3538 - CONFIG_ENV_MAX_ENTRIES
3540 Maximum number of entries in the hash table that is used
3541 internally to store the environment settings. The default
3542 setting is supposed to be generous and should work in most
3543 cases. This setting can be used to tune behaviour; see
3544 lib/hashtable.c for details.
3546 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3547 - CONFIG_ENV_FLAGS_LIST_STATIC
3548 Enable validation of the values given to environment variables when
3549 calling env set. Variables can be restricted to only decimal,
3550 hexadecimal, or boolean. If CONFIG_CMD_NET is also defined,
3551 the variables can also be restricted to IP address or MAC address.
3553 The format of the list is:
3554 type_attribute = [s|d|x|b|i|m]
3555 access_attribute = [a|r|o|c]
3556 attributes = type_attribute[access_attribute]
3557 entry = variable_name[:attributes]
3560 The type attributes are:
3561 s - String (default)
3564 b - Boolean ([1yYtT|0nNfF])
3568 The access attributes are:
3574 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3575 Define this to a list (string) to define the ".flags"
3576 environment variable in the default or embedded environment.
3578 - CONFIG_ENV_FLAGS_LIST_STATIC
3579 Define this to a list (string) to define validation that
3580 should be done if an entry is not found in the ".flags"
3581 environment variable. To override a setting in the static
3582 list, simply add an entry for the same variable name to the
3585 If CONFIG_REGEX is defined, the variable_name above is evaluated as a
3586 regular expression. This allows multiple variables to define the same
3587 flags without explicitly listing them for each variable.
3589 - CONFIG_ENV_ACCESS_IGNORE_FORCE
3590 If defined, don't allow the -f switch to env set override variable
3594 If stdint.h is available with your toolchain you can define this
3595 option to enable it. You can provide option 'USE_STDINT=1' when
3596 building U-Boot to enable this.
3598 The following definitions that deal with the placement and management
3599 of environment data (variable area); in general, we support the
3600 following configurations:
3602 - CONFIG_BUILD_ENVCRC:
3604 Builds up envcrc with the target environment so that external utils
3605 may easily extract it and embed it in final U-Boot images.
3607 - CONFIG_ENV_IS_IN_FLASH:
3609 Define this if the environment is in flash memory.
3611 a) The environment occupies one whole flash sector, which is
3612 "embedded" in the text segment with the U-Boot code. This
3613 happens usually with "bottom boot sector" or "top boot
3614 sector" type flash chips, which have several smaller
3615 sectors at the start or the end. For instance, such a
3616 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
3617 such a case you would place the environment in one of the
3618 4 kB sectors - with U-Boot code before and after it. With
3619 "top boot sector" type flash chips, you would put the
3620 environment in one of the last sectors, leaving a gap
3621 between U-Boot and the environment.
3623 - CONFIG_ENV_OFFSET:
3625 Offset of environment data (variable area) to the
3626 beginning of flash memory; for instance, with bottom boot
3627 type flash chips the second sector can be used: the offset
3628 for this sector is given here.
3630 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
3634 This is just another way to specify the start address of
3635 the flash sector containing the environment (instead of
3638 - CONFIG_ENV_SECT_SIZE:
3640 Size of the sector containing the environment.
3643 b) Sometimes flash chips have few, equal sized, BIG sectors.
3644 In such a case you don't want to spend a whole sector for
3649 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
3650 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
3651 of this flash sector for the environment. This saves
3652 memory for the RAM copy of the environment.
3654 It may also save flash memory if you decide to use this
3655 when your environment is "embedded" within U-Boot code,
3656 since then the remainder of the flash sector could be used
3657 for U-Boot code. It should be pointed out that this is
3658 STRONGLY DISCOURAGED from a robustness point of view:
3659 updating the environment in flash makes it always
3660 necessary to erase the WHOLE sector. If something goes
3661 wrong before the contents has been restored from a copy in
3662 RAM, your target system will be dead.
3664 - CONFIG_ENV_ADDR_REDUND
3665 CONFIG_ENV_SIZE_REDUND
3667 These settings describe a second storage area used to hold
3668 a redundant copy of the environment data, so that there is
3669 a valid backup copy in case there is a power failure during
3670 a "saveenv" operation.
3672 BE CAREFUL! Any changes to the flash layout, and some changes to the
3673 source code will make it necessary to adapt <board>/u-boot.lds*
3677 - CONFIG_ENV_IS_IN_NVRAM:
3679 Define this if you have some non-volatile memory device
3680 (NVRAM, battery buffered SRAM) which you want to use for the
3686 These two #defines are used to determine the memory area you
3687 want to use for environment. It is assumed that this memory
3688 can just be read and written to, without any special
3691 BE CAREFUL! The first access to the environment happens quite early
3692 in U-Boot initialization (when we try to get the setting of for the
3693 console baudrate). You *MUST* have mapped your NVRAM area then, or
3696 Please note that even with NVRAM we still use a copy of the
3697 environment in RAM: we could work on NVRAM directly, but we want to
3698 keep settings there always unmodified except somebody uses "saveenv"
3699 to save the current settings.
3702 - CONFIG_ENV_IS_IN_EEPROM:
3704 Use this if you have an EEPROM or similar serial access
3705 device and a driver for it.
3707 - CONFIG_ENV_OFFSET:
3710 These two #defines specify the offset and size of the
3711 environment area within the total memory of your EEPROM.
3713 - CONFIG_SYS_I2C_EEPROM_ADDR:
3714 If defined, specified the chip address of the EEPROM device.
3715 The default address is zero.
3717 - CONFIG_SYS_I2C_EEPROM_BUS:
3718 If defined, specified the i2c bus of the EEPROM device.
3720 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
3721 If defined, the number of bits used to address bytes in a
3722 single page in the EEPROM device. A 64 byte page, for example
3723 would require six bits.
3725 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
3726 If defined, the number of milliseconds to delay between
3727 page writes. The default is zero milliseconds.
3729 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
3730 The length in bytes of the EEPROM memory array address. Note
3731 that this is NOT the chip address length!
3733 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
3734 EEPROM chips that implement "address overflow" are ones
3735 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
3736 address and the extra bits end up in the "chip address" bit
3737 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
3740 Note that we consider the length of the address field to
3741 still be one byte because the extra address bits are hidden
3742 in the chip address.
3744 - CONFIG_SYS_EEPROM_SIZE:
3745 The size in bytes of the EEPROM device.
3747 - CONFIG_ENV_EEPROM_IS_ON_I2C
3748 define this, if you have I2C and SPI activated, and your
3749 EEPROM, which holds the environment, is on the I2C bus.
3751 - CONFIG_I2C_ENV_EEPROM_BUS
3752 if you have an Environment on an EEPROM reached over
3753 I2C muxes, you can define here, how to reach this
3754 EEPROM. For example:
3756 #define CONFIG_I2C_ENV_EEPROM_BUS 1
3758 EEPROM which holds the environment, is reached over
3759 a pca9547 i2c mux with address 0x70, channel 3.
3761 - CONFIG_ENV_IS_IN_DATAFLASH:
3763 Define this if you have a DataFlash memory device which you
3764 want to use for the environment.
3766 - CONFIG_ENV_OFFSET:
3770 These three #defines specify the offset and size of the
3771 environment area within the total memory of your DataFlash placed
3772 at the specified address.
3774 - CONFIG_ENV_IS_IN_SPI_FLASH:
3776 Define this if you have a SPI Flash memory device which you
3777 want to use for the environment.
3779 - CONFIG_ENV_OFFSET:
3782 These two #defines specify the offset and size of the
3783 environment area within the SPI Flash. CONFIG_ENV_OFFSET must be
3784 aligned to an erase sector boundary.
3786 - CONFIG_ENV_SECT_SIZE:
3788 Define the SPI flash's sector size.
3790 - CONFIG_ENV_OFFSET_REDUND (optional):
3792 This setting describes a second storage area of CONFIG_ENV_SIZE
3793 size used to hold a redundant copy of the environment data, so
3794 that there is a valid backup copy in case there is a power failure
3795 during a "saveenv" operation. CONFIG_ENV_OFFSET_REDUND must be
3796 aligned to an erase sector boundary.
3798 - CONFIG_ENV_SPI_BUS (optional):
3799 - CONFIG_ENV_SPI_CS (optional):
3801 Define the SPI bus and chip select. If not defined they will be 0.
3803 - CONFIG_ENV_SPI_MAX_HZ (optional):
3805 Define the SPI max work clock. If not defined then use 1MHz.
3807 - CONFIG_ENV_SPI_MODE (optional):
3809 Define the SPI work mode. If not defined then use SPI_MODE_3.
3811 - CONFIG_ENV_IS_IN_REMOTE:
3813 Define this if you have a remote memory space which you
3814 want to use for the local device's environment.
3819 These two #defines specify the address and size of the
3820 environment area within the remote memory space. The
3821 local device can get the environment from remote memory
3822 space by SRIO or PCIE links.
3824 BE CAREFUL! For some special cases, the local device can not use
3825 "saveenv" command. For example, the local device will get the
3826 environment stored in a remote NOR flash by SRIO or PCIE link,
3827 but it can not erase, write this NOR flash by SRIO or PCIE interface.
3829 - CONFIG_ENV_IS_IN_NAND:
3831 Define this if you have a NAND device which you want to use
3832 for the environment.
3834 - CONFIG_ENV_OFFSET:
3837 These two #defines specify the offset and size of the environment
3838 area within the first NAND device. CONFIG_ENV_OFFSET must be
3839 aligned to an erase block boundary.
3841 - CONFIG_ENV_OFFSET_REDUND (optional):
3843 This setting describes a second storage area of CONFIG_ENV_SIZE
3844 size used to hold a redundant copy of the environment data, so
3845 that there is a valid backup copy in case there is a power failure
3846 during a "saveenv" operation. CONFIG_ENV_OFFSET_REDUND must be
3847 aligned to an erase block boundary.
3849 - CONFIG_ENV_RANGE (optional):
3851 Specifies the length of the region in which the environment
3852 can be written. This should be a multiple of the NAND device's
3853 block size. Specifying a range with more erase blocks than
3854 are needed to hold CONFIG_ENV_SIZE allows bad blocks within
3855 the range to be avoided.
3857 - CONFIG_ENV_OFFSET_OOB (optional):
3859 Enables support for dynamically retrieving the offset of the
3860 environment from block zero's out-of-band data. The
3861 "nand env.oob" command can be used to record this offset.
3862 Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
3863 using CONFIG_ENV_OFFSET_OOB.
3865 - CONFIG_NAND_ENV_DST
3867 Defines address in RAM to which the nand_spl code should copy the
3868 environment. If redundant environment is used, it will be copied to
3869 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
3871 - CONFIG_ENV_IS_IN_UBI:
3873 Define this if you have an UBI volume that you want to use for the
3874 environment. This has the benefit of wear-leveling the environment
3875 accesses, which is important on NAND.
3877 - CONFIG_ENV_UBI_PART:
3879 Define this to a string that is the mtd partition containing the UBI.
3881 - CONFIG_ENV_UBI_VOLUME:
3883 Define this to the name of the volume that you want to store the
3886 - CONFIG_ENV_UBI_VOLUME_REDUND:
3888 Define this to the name of another volume to store a second copy of
3889 the environment in. This will enable redundant environments in UBI.
3890 It is assumed that both volumes are in the same MTD partition.
3892 - CONFIG_UBI_SILENCE_MSG
3893 - CONFIG_UBIFS_SILENCE_MSG
3895 You will probably want to define these to avoid a really noisy system
3896 when storing the env in UBI.
3898 - CONFIG_ENV_IS_IN_FAT:
3899 Define this if you want to use the FAT file system for the environment.
3901 - FAT_ENV_INTERFACE:
3903 Define this to a string that is the name of the block device.
3905 - FAT_ENV_DEVICE_AND_PART:
3907 Define this to a string to specify the partition of the device. It can
3910 "D:P", "D:0", "D", "D:" or "D:auto" (D, P are integers. And P >= 1)
3911 - "D:P": device D partition P. Error occurs if device D has no
3914 - "D" or "D:": device D partition 1 if device D has partition
3915 table, or the whole device D if has no partition
3917 - "D:auto": first partition in device D with bootable flag set.
3918 If none, first valid partition in device D. If no
3919 partition table then means device D.
3923 It's a string of the FAT file name. This file use to store the
3927 This should be defined. Otherwise it cannot save the environment file.
3929 - CONFIG_ENV_IS_IN_MMC:
3931 Define this if you have an MMC device which you want to use for the
3934 - CONFIG_SYS_MMC_ENV_DEV:
3936 Specifies which MMC device the environment is stored in.
3938 - CONFIG_SYS_MMC_ENV_PART (optional):
3940 Specifies which MMC partition the environment is stored in. If not
3941 set, defaults to partition 0, the user area. Common values might be
3942 1 (first MMC boot partition), 2 (second MMC boot partition).
3944 - CONFIG_ENV_OFFSET:
3947 These two #defines specify the offset and size of the environment
3948 area within the specified MMC device.
3950 If offset is positive (the usual case), it is treated as relative to
3951 the start of the MMC partition. If offset is negative, it is treated
3952 as relative to the end of the MMC partition. This can be useful if
3953 your board may be fitted with different MMC devices, which have
3954 different sizes for the MMC partitions, and you always want the
3955 environment placed at the very end of the partition, to leave the
3956 maximum possible space before it, to store other data.
3958 These two values are in units of bytes, but must be aligned to an
3959 MMC sector boundary.
3961 - CONFIG_ENV_OFFSET_REDUND (optional):
3963 Specifies a second storage area, of CONFIG_ENV_SIZE size, used to
3964 hold a redundant copy of the environment data. This provides a
3965 valid backup copy in case the other copy is corrupted, e.g. due
3966 to a power failure during a "saveenv" operation.
3968 This value may also be positive or negative; this is handled in the
3969 same way as CONFIG_ENV_OFFSET.
3971 This value is also in units of bytes, but must also be aligned to
3972 an MMC sector boundary.
3974 - CONFIG_ENV_SIZE_REDUND (optional):
3976 This value need not be set, even when CONFIG_ENV_OFFSET_REDUND is
3977 set. If this value is set, it must be set to the same value as
3980 - CONFIG_SYS_SPI_INIT_OFFSET
3982 Defines offset to the initial SPI buffer area in DPRAM. The
3983 area is used at an early stage (ROM part) if the environment
3984 is configured to reside in the SPI EEPROM: We need a 520 byte
3985 scratch DPRAM area. It is used between the two initialization
3986 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
3987 to be a good choice since it makes it far enough from the
3988 start of the data area as well as from the stack pointer.
3990 Please note that the environment is read-only until the monitor
3991 has been relocated to RAM and a RAM copy of the environment has been
3992 created; also, when using EEPROM you will have to use getenv_f()
3993 until then to read environment variables.
3995 The environment is protected by a CRC32 checksum. Before the monitor
3996 is relocated into RAM, as a result of a bad CRC you will be working
3997 with the compiled-in default environment - *silently*!!! [This is
3998 necessary, because the first environment variable we need is the
3999 "baudrate" setting for the console - if we have a bad CRC, we don't
4000 have any device yet where we could complain.]
4002 Note: once the monitor has been relocated, then it will complain if
4003 the default environment is used; a new CRC is computed as soon as you
4004 use the "saveenv" command to store a valid environment.
4006 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
4007 Echo the inverted Ethernet link state to the fault LED.
4009 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
4010 also needs to be defined.
4012 - CONFIG_SYS_FAULT_MII_ADDR:
4013 MII address of the PHY to check for the Ethernet link state.
4015 - CONFIG_NS16550_MIN_FUNCTIONS:
4016 Define this if you desire to only have use of the NS16550_init
4017 and NS16550_putc functions for the serial driver located at
4018 drivers/serial/ns16550.c. This option is useful for saving
4019 space for already greatly restricted images, including but not
4020 limited to NAND_SPL configurations.
4022 - CONFIG_DISPLAY_BOARDINFO
4023 Display information about the board that U-Boot is running on
4024 when U-Boot starts up. The board function checkboard() is called
4027 - CONFIG_DISPLAY_BOARDINFO_LATE
4028 Similar to the previous option, but display this information
4029 later, once stdio is running and output goes to the LCD, if
4032 - CONFIG_BOARD_SIZE_LIMIT:
4033 Maximum size of the U-Boot image. When defined, the
4034 build system checks that the actual size does not
4037 Low Level (hardware related) configuration options:
4038 ---------------------------------------------------
4040 - CONFIG_SYS_CACHELINE_SIZE:
4041 Cache Line Size of the CPU.
4043 - CONFIG_SYS_DEFAULT_IMMR:
4044 Default address of the IMMR after system reset.
4046 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
4047 and RPXsuper) to be able to adjust the position of
4048 the IMMR register after a reset.
4050 - CONFIG_SYS_CCSRBAR_DEFAULT:
4051 Default (power-on reset) physical address of CCSR on Freescale
4054 - CONFIG_SYS_CCSRBAR:
4055 Virtual address of CCSR. On a 32-bit build, this is typically
4056 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
4058 CONFIG_SYS_DEFAULT_IMMR must also be set to this value,
4059 for cross-platform code that uses that macro instead.
4061 - CONFIG_SYS_CCSRBAR_PHYS:
4062 Physical address of CCSR. CCSR can be relocated to a new
4063 physical address, if desired. In this case, this macro should
4064 be set to that address. Otherwise, it should be set to the
4065 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
4066 is typically relocated on 36-bit builds. It is recommended
4067 that this macro be defined via the _HIGH and _LOW macros:
4069 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
4070 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
4072 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
4073 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
4074 either 0 (32-bit build) or 0xF (36-bit build). This macro is
4075 used in assembly code, so it must not contain typecasts or
4076 integer size suffixes (e.g. "ULL").
4078 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
4079 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
4080 used in assembly code, so it must not contain typecasts or
4081 integer size suffixes (e.g. "ULL").
4083 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
4084 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
4085 forced to a value that ensures that CCSR is not relocated.
4087 - Floppy Disk Support:
4088 CONFIG_SYS_FDC_DRIVE_NUMBER
4090 the default drive number (default value 0)
4092 CONFIG_SYS_ISA_IO_STRIDE
4094 defines the spacing between FDC chipset registers
4097 CONFIG_SYS_ISA_IO_OFFSET
4099 defines the offset of register from address. It
4100 depends on which part of the data bus is connected to
4101 the FDC chipset. (default value 0)
4103 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
4104 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
4107 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
4108 fdc_hw_init() is called at the beginning of the FDC
4109 setup. fdc_hw_init() must be provided by the board
4110 source code. It is used to make hardware-dependent
4114 Most IDE controllers were designed to be connected with PCI
4115 interface. Only few of them were designed for AHB interface.
4116 When software is doing ATA command and data transfer to
4117 IDE devices through IDE-AHB controller, some additional
4118 registers accessing to these kind of IDE-AHB controller
4121 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
4122 DO NOT CHANGE unless you know exactly what you're
4123 doing! (11-4) [MPC8xx/82xx systems only]
4125 - CONFIG_SYS_INIT_RAM_ADDR:
4127 Start address of memory area that can be used for
4128 initial data and stack; please note that this must be
4129 writable memory that is working WITHOUT special
4130 initialization, i. e. you CANNOT use normal RAM which
4131 will become available only after programming the
4132 memory controller and running certain initialization
4135 U-Boot uses the following memory types:
4136 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
4137 - MPC824X: data cache
4138 - PPC4xx: data cache
4140 - CONFIG_SYS_GBL_DATA_OFFSET:
4142 Offset of the initial data structure in the memory
4143 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
4144 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
4145 data is located at the end of the available space
4146 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
4147 GENERATED_GBL_DATA_SIZE), and the initial stack is just
4148 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
4149 CONFIG_SYS_GBL_DATA_OFFSET) downward.
4152 On the MPC824X (or other systems that use the data
4153 cache for initial memory) the address chosen for
4154 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
4155 point to an otherwise UNUSED address space between
4156 the top of RAM and the start of the PCI space.
4158 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
4160 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
4162 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
4164 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
4166 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
4168 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
4170 - CONFIG_SYS_OR_TIMING_SDRAM:
4173 - CONFIG_SYS_MAMR_PTA:
4174 periodic timer for refresh
4176 - CONFIG_SYS_DER: Debug Event Register (37-47)
4178 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
4179 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
4180 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
4181 CONFIG_SYS_BR1_PRELIM:
4182 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
4184 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
4185 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
4186 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
4187 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
4189 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
4190 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
4191 Machine Mode Register and Memory Periodic Timer
4192 Prescaler definitions (SDRAM timing)
4194 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
4195 enable I2C microcode relocation patch (MPC8xx);
4196 define relocation offset in DPRAM [DSP2]
4198 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
4199 enable SMC microcode relocation patch (MPC8xx);
4200 define relocation offset in DPRAM [SMC1]
4202 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
4203 enable SPI microcode relocation patch (MPC8xx);
4204 define relocation offset in DPRAM [SCC4]
4206 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
4207 Offset of the bootmode word in DPRAM used by post
4208 (Power On Self Tests). This definition overrides
4209 #define'd default value in commproc.h resp.
4212 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
4213 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
4214 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
4215 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
4216 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
4217 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
4218 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
4219 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
4220 Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
4222 - CONFIG_PCI_DISABLE_PCIE:
4223 Disable PCI-Express on systems where it is supported but not
4226 - CONFIG_PCI_ENUM_ONLY
4227 Only scan through and get the devices on the buses.
4228 Don't do any setup work, presumably because someone or
4229 something has already done it, and we don't need to do it
4230 a second time. Useful for platforms that are pre-booted
4231 by coreboot or similar.
4233 - CONFIG_PCI_INDIRECT_BRIDGE:
4234 Enable support for indirect PCI bridges.
4237 Chip has SRIO or not
4240 Board has SRIO 1 port available
4243 Board has SRIO 2 port available
4245 - CONFIG_SRIO_PCIE_BOOT_MASTER
4246 Board can support master function for Boot from SRIO and PCIE
4248 - CONFIG_SYS_SRIOn_MEM_VIRT:
4249 Virtual Address of SRIO port 'n' memory region
4251 - CONFIG_SYS_SRIOn_MEM_PHYS:
4252 Physical Address of SRIO port 'n' memory region
4254 - CONFIG_SYS_SRIOn_MEM_SIZE:
4255 Size of SRIO port 'n' memory region
4257 - CONFIG_SYS_NAND_BUSWIDTH_16BIT
4258 Defined to tell the NAND controller that the NAND chip is using
4260 Not all NAND drivers use this symbol.
4261 Example of drivers that use it:
4262 - drivers/mtd/nand/ndfc.c
4263 - drivers/mtd/nand/mxc_nand.c
4265 - CONFIG_SYS_NDFC_EBC0_CFG
4266 Sets the EBC0_CFG register for the NDFC. If not defined
4267 a default value will be used.
4270 Get DDR timing information from an I2C EEPROM. Common
4271 with pluggable memory modules such as SODIMMs
4274 I2C address of the SPD EEPROM
4276 - CONFIG_SYS_SPD_BUS_NUM
4277 If SPD EEPROM is on an I2C bus other than the first
4278 one, specify here. Note that the value must resolve
4279 to something your driver can deal with.
4281 - CONFIG_SYS_DDR_RAW_TIMING
4282 Get DDR timing information from other than SPD. Common with
4283 soldered DDR chips onboard without SPD. DDR raw timing
4284 parameters are extracted from datasheet and hard-coded into
4285 header files or board specific files.
4287 - CONFIG_FSL_DDR_INTERACTIVE
4288 Enable interactive DDR debugging. See doc/README.fsl-ddr.
4290 - CONFIG_FSL_DDR_SYNC_REFRESH
4291 Enable sync of refresh for multiple controllers.
4293 - CONFIG_FSL_DDR_BIST
4294 Enable built-in memory test for Freescale DDR controllers.
4296 - CONFIG_SYS_83XX_DDR_USES_CS0
4297 Only for 83xx systems. If specified, then DDR should
4298 be configured using CS0 and CS1 instead of CS2 and CS3.
4300 - CONFIG_ETHER_ON_FEC[12]
4301 Define to enable FEC[12] on a 8xx series processor.
4303 - CONFIG_FEC[12]_PHY
4304 Define to the hardcoded PHY address which corresponds
4305 to the given FEC; i. e.
4306 #define CONFIG_FEC1_PHY 4
4307 means that the PHY with address 4 is connected to FEC1
4309 When set to -1, means to probe for first available.
4311 - CONFIG_FEC[12]_PHY_NORXERR
4312 The PHY does not have a RXERR line (RMII only).
4313 (so program the FEC to ignore it).
4316 Enable RMII mode for all FECs.
4317 Note that this is a global option, we can't
4318 have one FEC in standard MII mode and another in RMII mode.
4320 - CONFIG_CRC32_VERIFY
4321 Add a verify option to the crc32 command.
4324 => crc32 -v <address> <count> <crc32>
4326 Where address/count indicate a memory area
4327 and crc32 is the correct crc32 which the
4331 Add the "loopw" memory command. This only takes effect if
4332 the memory commands are activated globally (CONFIG_CMD_MEM).
4335 Add the "mdc" and "mwc" memory commands. These are cyclic
4340 This command will print 4 bytes (10,11,12,13) each 500 ms.
4342 => mwc.l 100 12345678 10
4343 This command will write 12345678 to address 100 all 10 ms.
4345 This only takes effect if the memory commands are activated
4346 globally (CONFIG_CMD_MEM).
4348 - CONFIG_SKIP_LOWLEVEL_INIT
4349 [ARM, NDS32, MIPS only] If this variable is defined, then certain
4350 low level initializations (like setting up the memory
4351 controller) are omitted and/or U-Boot does not
4352 relocate itself into RAM.
4354 Normally this variable MUST NOT be defined. The only
4355 exception is when U-Boot is loaded (to RAM) by some
4356 other boot loader or by a debugger which performs
4357 these initializations itself.
4359 - CONFIG_SKIP_LOWLEVEL_INIT_ONLY
4360 [ARM926EJ-S only] This allows just the call to lowlevel_init()
4361 to be skipped. The normal CP15 init (such as enabling the
4362 instruction cache) is still performed.
4365 Modifies the behaviour of start.S when compiling a loader
4366 that is executed before the actual U-Boot. E.g. when
4367 compiling a NAND SPL.
4370 Modifies the behaviour of start.S when compiling a loader
4371 that is executed after the SPL and before the actual U-Boot.
4372 It is loaded by the SPL.
4374 - CONFIG_SYS_MPC85XX_NO_RESETVEC
4375 Only for 85xx systems. If this variable is specified, the section
4376 .resetvec is not kept and the section .bootpg is placed in the
4377 previous 4k of the .text section.
4379 - CONFIG_ARCH_MAP_SYSMEM
4380 Generally U-Boot (and in particular the md command) uses
4381 effective address. It is therefore not necessary to regard
4382 U-Boot address as virtual addresses that need to be translated
4383 to physical addresses. However, sandbox requires this, since
4384 it maintains its own little RAM buffer which contains all
4385 addressable memory. This option causes some memory accesses
4386 to be mapped through map_sysmem() / unmap_sysmem().
4388 - CONFIG_X86_RESET_VECTOR
4389 If defined, the x86 reset vector code is included. This is not
4390 needed when U-Boot is running from Coreboot.
4392 - CONFIG_SPL_AM33XX_ENABLE_RTC32K_OSC:
4393 Enables the RTC32K OSC on AM33xx based plattforms
4395 - CONFIG_SYS_NAND_NO_SUBPAGE_WRITE
4396 Option to disable subpage write in NAND driver
4397 driver that uses this:
4398 drivers/mtd/nand/davinci_nand.c
4400 Freescale QE/FMAN Firmware Support:
4401 -----------------------------------
4403 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
4404 loading of "firmware", which is encoded in the QE firmware binary format.
4405 This firmware often needs to be loaded during U-Boot booting, so macros
4406 are used to identify the storage device (NOR flash, SPI, etc) and the address
4409 - CONFIG_SYS_FMAN_FW_ADDR
4410 The address in the storage device where the FMAN microcode is located. The
4411 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4414 - CONFIG_SYS_QE_FW_ADDR
4415 The address in the storage device where the QE microcode is located. The
4416 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4419 - CONFIG_SYS_QE_FMAN_FW_LENGTH
4420 The maximum possible size of the firmware. The firmware binary format
4421 has a field that specifies the actual size of the firmware, but it
4422 might not be possible to read any part of the firmware unless some
4423 local storage is allocated to hold the entire firmware first.
4425 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
4426 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
4427 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
4428 virtual address in NOR flash.
4430 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
4431 Specifies that QE/FMAN firmware is located in NAND flash.
4432 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
4434 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
4435 Specifies that QE/FMAN firmware is located on the primary SD/MMC
4436 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
4438 - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
4439 Specifies that QE/FMAN firmware is located in the remote (master)
4440 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
4441 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
4442 window->master inbound window->master LAW->the ucode address in
4443 master's memory space.
4445 Freescale Layerscape Management Complex Firmware Support:
4446 ---------------------------------------------------------
4447 The Freescale Layerscape Management Complex (MC) supports the loading of
4449 This firmware often needs to be loaded during U-Boot booting, so macros
4450 are used to identify the storage device (NOR flash, SPI, etc) and the address
4453 - CONFIG_FSL_MC_ENET
4454 Enable the MC driver for Layerscape SoCs.
4456 Freescale Layerscape Debug Server Support:
4457 -------------------------------------------
4458 The Freescale Layerscape Debug Server Support supports the loading of
4459 "Debug Server firmware" and triggering SP boot-rom.
4460 This firmware often needs to be loaded during U-Boot booting.
4462 - CONFIG_SYS_MC_RSV_MEM_ALIGN
4463 Define alignment of reserved memory MC requires
4468 In order to achieve reproducible builds, timestamps used in the U-Boot build
4469 process have to be set to a fixed value.
4471 This is done using the SOURCE_DATE_EPOCH environment variable.
4472 SOURCE_DATE_EPOCH is to be set on the build host's shell, not as a configuration
4473 option for U-Boot or an environment variable in U-Boot.
4475 SOURCE_DATE_EPOCH should be set to a number of seconds since the epoch, in UTC.
4477 Building the Software:
4478 ======================
4480 Building U-Boot has been tested in several native build environments
4481 and in many different cross environments. Of course we cannot support
4482 all possibly existing versions of cross development tools in all
4483 (potentially obsolete) versions. In case of tool chain problems we
4484 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
4485 which is extensively used to build and test U-Boot.
4487 If you are not using a native environment, it is assumed that you
4488 have GNU cross compiling tools available in your path. In this case,
4489 you must set the environment variable CROSS_COMPILE in your shell.
4490 Note that no changes to the Makefile or any other source files are
4491 necessary. For example using the ELDK on a 4xx CPU, please enter:
4493 $ CROSS_COMPILE=ppc_4xx-
4494 $ export CROSS_COMPILE
4496 Note: If you wish to generate Windows versions of the utilities in
4497 the tools directory you can use the MinGW toolchain
4498 (http://www.mingw.org). Set your HOST tools to the MinGW
4499 toolchain and execute 'make tools'. For example:
4501 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
4503 Binaries such as tools/mkimage.exe will be created which can
4504 be executed on computers running Windows.
4506 U-Boot is intended to be simple to build. After installing the
4507 sources you must configure U-Boot for one specific board type. This
4512 where "NAME_defconfig" is the name of one of the existing configu-
4513 rations; see boards.cfg for supported names.
4515 Note: for some board special configuration names may exist; check if
4516 additional information is available from the board vendor; for
4517 instance, the TQM823L systems are available without (standard)
4518 or with LCD support. You can select such additional "features"
4519 when choosing the configuration, i. e.
4521 make TQM823L_defconfig
4522 - will configure for a plain TQM823L, i. e. no LCD support
4524 make TQM823L_LCD_defconfig
4525 - will configure for a TQM823L with U-Boot console on LCD
4530 Finally, type "make all", and you should get some working U-Boot
4531 images ready for download to / installation on your system:
4533 - "u-boot.bin" is a raw binary image
4534 - "u-boot" is an image in ELF binary format
4535 - "u-boot.srec" is in Motorola S-Record format
4537 By default the build is performed locally and the objects are saved
4538 in the source directory. One of the two methods can be used to change
4539 this behavior and build U-Boot to some external directory:
4541 1. Add O= to the make command line invocations:
4543 make O=/tmp/build distclean
4544 make O=/tmp/build NAME_defconfig
4545 make O=/tmp/build all
4547 2. Set environment variable KBUILD_OUTPUT to point to the desired location:
4549 export KBUILD_OUTPUT=/tmp/build
4554 Note that the command line "O=" setting overrides the KBUILD_OUTPUT environment
4558 Please be aware that the Makefiles assume you are using GNU make, so
4559 for instance on NetBSD you might need to use "gmake" instead of
4563 If the system board that you have is not listed, then you will need
4564 to port U-Boot to your hardware platform. To do this, follow these
4567 1. Create a new directory to hold your board specific code. Add any
4568 files you need. In your board directory, you will need at least
4569 the "Makefile" and a "<board>.c".
4570 2. Create a new configuration file "include/configs/<board>.h" for
4572 3. If you're porting U-Boot to a new CPU, then also create a new
4573 directory to hold your CPU specific code. Add any files you need.
4574 4. Run "make <board>_defconfig" with your new name.
4575 5. Type "make", and you should get a working "u-boot.srec" file
4576 to be installed on your target system.
4577 6. Debug and solve any problems that might arise.
4578 [Of course, this last step is much harder than it sounds.]
4581 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
4582 ==============================================================
4584 If you have modified U-Boot sources (for instance added a new board
4585 or support for new devices, a new CPU, etc.) you are expected to
4586 provide feedback to the other developers. The feedback normally takes
4587 the form of a "patch", i. e. a context diff against a certain (latest
4588 official or latest in the git repository) version of U-Boot sources.
4590 But before you submit such a patch, please verify that your modifi-
4591 cation did not break existing code. At least make sure that *ALL* of
4592 the supported boards compile WITHOUT ANY compiler warnings. To do so,
4593 just run the buildman script (tools/buildman/buildman), which will
4594 configure and build U-Boot for ALL supported system. Be warned, this
4595 will take a while. Please see the buildman README, or run 'buildman -H'
4599 See also "U-Boot Porting Guide" below.
4602 Monitor Commands - Overview:
4603 ============================
4605 go - start application at address 'addr'
4606 run - run commands in an environment variable
4607 bootm - boot application image from memory
4608 bootp - boot image via network using BootP/TFTP protocol
4609 bootz - boot zImage from memory
4610 tftpboot- boot image via network using TFTP protocol
4611 and env variables "ipaddr" and "serverip"
4612 (and eventually "gatewayip")
4613 tftpput - upload a file via network using TFTP protocol
4614 rarpboot- boot image via network using RARP/TFTP protocol
4615 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
4616 loads - load S-Record file over serial line
4617 loadb - load binary file over serial line (kermit mode)
4619 mm - memory modify (auto-incrementing)
4620 nm - memory modify (constant address)
4621 mw - memory write (fill)
4623 cmp - memory compare
4624 crc32 - checksum calculation
4625 i2c - I2C sub-system
4626 sspi - SPI utility commands
4627 base - print or set address offset
4628 printenv- print environment variables
4629 setenv - set environment variables
4630 saveenv - save environment variables to persistent storage
4631 protect - enable or disable FLASH write protection
4632 erase - erase FLASH memory
4633 flinfo - print FLASH memory information
4634 nand - NAND memory operations (see doc/README.nand)
4635 bdinfo - print Board Info structure
4636 iminfo - print header information for application image
4637 coninfo - print console devices and informations
4638 ide - IDE sub-system
4639 loop - infinite loop on address range
4640 loopw - infinite write loop on address range
4641 mtest - simple RAM test
4642 icache - enable or disable instruction cache
4643 dcache - enable or disable data cache
4644 reset - Perform RESET of the CPU
4645 echo - echo args to console
4646 version - print monitor version
4647 help - print online help
4648 ? - alias for 'help'
4651 Monitor Commands - Detailed Description:
4652 ========================================
4656 For now: just type "help <command>".
4659 Environment Variables:
4660 ======================
4662 U-Boot supports user configuration using Environment Variables which
4663 can be made persistent by saving to Flash memory.
4665 Environment Variables are set using "setenv", printed using
4666 "printenv", and saved to Flash using "saveenv". Using "setenv"
4667 without a value can be used to delete a variable from the
4668 environment. As long as you don't save the environment you are
4669 working with an in-memory copy. In case the Flash area containing the
4670 environment is erased by accident, a default environment is provided.
4672 Some configuration options can be set using Environment Variables.
4674 List of environment variables (most likely not complete):
4676 baudrate - see CONFIG_BAUDRATE
4678 bootdelay - see CONFIG_BOOTDELAY
4680 bootcmd - see CONFIG_BOOTCOMMAND
4682 bootargs - Boot arguments when booting an RTOS image
4684 bootfile - Name of the image to load with TFTP
4686 bootm_low - Memory range available for image processing in the bootm
4687 command can be restricted. This variable is given as
4688 a hexadecimal number and defines lowest address allowed
4689 for use by the bootm command. See also "bootm_size"
4690 environment variable. Address defined by "bootm_low" is
4691 also the base of the initial memory mapping for the Linux
4692 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
4695 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
4696 This variable is given as a hexadecimal number and it
4697 defines the size of the memory region starting at base
4698 address bootm_low that is accessible by the Linux kernel
4699 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
4700 as the default value if it is defined, and bootm_size is
4703 bootm_size - Memory range available for image processing in the bootm
4704 command can be restricted. This variable is given as
4705 a hexadecimal number and defines the size of the region
4706 allowed for use by the bootm command. See also "bootm_low"
4707 environment variable.
4709 updatefile - Location of the software update file on a TFTP server, used
4710 by the automatic software update feature. Please refer to
4711 documentation in doc/README.update for more details.
4713 autoload - if set to "no" (any string beginning with 'n'),
4714 "bootp" will just load perform a lookup of the
4715 configuration from the BOOTP server, but not try to
4716 load any image using TFTP
4718 autostart - if set to "yes", an image loaded using the "bootp",
4719 "rarpboot", "tftpboot" or "diskboot" commands will
4720 be automatically started (by internally calling
4723 If set to "no", a standalone image passed to the
4724 "bootm" command will be copied to the load address
4725 (and eventually uncompressed), but NOT be started.
4726 This can be used to load and uncompress arbitrary
4729 fdt_high - if set this restricts the maximum address that the
4730 flattened device tree will be copied into upon boot.
4731 For example, if you have a system with 1 GB memory
4732 at physical address 0x10000000, while Linux kernel
4733 only recognizes the first 704 MB as low memory, you
4734 may need to set fdt_high as 0x3C000000 to have the
4735 device tree blob be copied to the maximum address
4736 of the 704 MB low memory, so that Linux kernel can
4737 access it during the boot procedure.
4739 If this is set to the special value 0xFFFFFFFF then
4740 the fdt will not be copied at all on boot. For this
4741 to work it must reside in writable memory, have
4742 sufficient padding on the end of it for u-boot to
4743 add the information it needs into it, and the memory
4744 must be accessible by the kernel.
4746 fdtcontroladdr- if set this is the address of the control flattened
4747 device tree used by U-Boot when CONFIG_OF_CONTROL is
4750 i2cfast - (PPC405GP|PPC405EP only)
4751 if set to 'y' configures Linux I2C driver for fast
4752 mode (400kHZ). This environment variable is used in
4753 initialization code. So, for changes to be effective
4754 it must be saved and board must be reset.
4756 initrd_high - restrict positioning of initrd images:
4757 If this variable is not set, initrd images will be
4758 copied to the highest possible address in RAM; this
4759 is usually what you want since it allows for
4760 maximum initrd size. If for some reason you want to
4761 make sure that the initrd image is loaded below the
4762 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
4763 variable to a value of "no" or "off" or "0".
4764 Alternatively, you can set it to a maximum upper
4765 address to use (U-Boot will still check that it
4766 does not overwrite the U-Boot stack and data).
4768 For instance, when you have a system with 16 MB
4769 RAM, and want to reserve 4 MB from use by Linux,
4770 you can do this by adding "mem=12M" to the value of
4771 the "bootargs" variable. However, now you must make
4772 sure that the initrd image is placed in the first
4773 12 MB as well - this can be done with
4775 setenv initrd_high 00c00000
4777 If you set initrd_high to 0xFFFFFFFF, this is an
4778 indication to U-Boot that all addresses are legal
4779 for the Linux kernel, including addresses in flash
4780 memory. In this case U-Boot will NOT COPY the
4781 ramdisk at all. This may be useful to reduce the
4782 boot time on your system, but requires that this
4783 feature is supported by your Linux kernel.
4785 ipaddr - IP address; needed for tftpboot command
4787 loadaddr - Default load address for commands like "bootp",
4788 "rarpboot", "tftpboot", "loadb" or "diskboot"
4790 loads_echo - see CONFIG_LOADS_ECHO
4792 serverip - TFTP server IP address; needed for tftpboot command
4794 bootretry - see CONFIG_BOOT_RETRY_TIME
4796 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
4798 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
4800 ethprime - controls which interface is used first.
4802 ethact - controls which interface is currently active.
4803 For example you can do the following
4805 => setenv ethact FEC
4806 => ping 192.168.0.1 # traffic sent on FEC
4807 => setenv ethact SCC
4808 => ping 10.0.0.1 # traffic sent on SCC
4810 ethrotate - When set to "no" U-Boot does not go through all
4811 available network interfaces.
4812 It just stays at the currently selected interface.
4814 netretry - When set to "no" each network operation will
4815 either succeed or fail without retrying.
4816 When set to "once" the network operation will
4817 fail when all the available network interfaces
4818 are tried once without success.
4819 Useful on scripts which control the retry operation
4822 npe_ucode - set load address for the NPE microcode
4824 silent_linux - If set then Linux will be told to boot silently, by
4825 changing the console to be empty. If "yes" it will be
4826 made silent. If "no" it will not be made silent. If
4827 unset, then it will be made silent if the U-Boot console
4830 tftpsrcp - If this is set, the value is used for TFTP's
4833 tftpdstp - If this is set, the value is used for TFTP's UDP
4834 destination port instead of the Well Know Port 69.
4836 tftpblocksize - Block size to use for TFTP transfers; if not set,
4837 we use the TFTP server's default block size
4839 tftptimeout - Retransmission timeout for TFTP packets (in milli-
4840 seconds, minimum value is 1000 = 1 second). Defines
4841 when a packet is considered to be lost so it has to
4842 be retransmitted. The default is 5000 = 5 seconds.
4843 Lowering this value may make downloads succeed
4844 faster in networks with high packet loss rates or
4845 with unreliable TFTP servers.
4847 tftptimeoutcountmax - maximum count of TFTP timeouts (no
4848 unit, minimum value = 0). Defines how many timeouts
4849 can happen during a single file transfer before that
4850 transfer is aborted. The default is 10, and 0 means
4851 'no timeouts allowed'. Increasing this value may help
4852 downloads succeed with high packet loss rates, or with
4853 unreliable TFTP servers or client hardware.
4855 vlan - When set to a value < 4095 the traffic over
4856 Ethernet is encapsulated/received over 802.1q
4859 bootpretryperiod - Period during which BOOTP/DHCP sends retries.
4860 Unsigned value, in milliseconds. If not set, the period will
4861 be either the default (28000), or a value based on
4862 CONFIG_NET_RETRY_COUNT, if defined. This value has
4863 precedence over the valu based on CONFIG_NET_RETRY_COUNT.
4865 The following image location variables contain the location of images
4866 used in booting. The "Image" column gives the role of the image and is
4867 not an environment variable name. The other columns are environment
4868 variable names. "File Name" gives the name of the file on a TFTP
4869 server, "RAM Address" gives the location in RAM the image will be
4870 loaded to, and "Flash Location" gives the image's address in NOR
4871 flash or offset in NAND flash.
4873 *Note* - these variables don't have to be defined for all boards, some
4874 boards currently use other variables for these purposes, and some
4875 boards use these variables for other purposes.
4877 Image File Name RAM Address Flash Location
4878 ----- --------- ----------- --------------
4879 u-boot u-boot u-boot_addr_r u-boot_addr
4880 Linux kernel bootfile kernel_addr_r kernel_addr
4881 device tree blob fdtfile fdt_addr_r fdt_addr
4882 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
4884 The following environment variables may be used and automatically
4885 updated by the network boot commands ("bootp" and "rarpboot"),
4886 depending the information provided by your boot server:
4888 bootfile - see above
4889 dnsip - IP address of your Domain Name Server
4890 dnsip2 - IP address of your secondary Domain Name Server
4891 gatewayip - IP address of the Gateway (Router) to use
4892 hostname - Target hostname
4894 netmask - Subnet Mask
4895 rootpath - Pathname of the root filesystem on the NFS server
4896 serverip - see above
4899 There are two special Environment Variables:
4901 serial# - contains hardware identification information such
4902 as type string and/or serial number
4903 ethaddr - Ethernet address
4905 These variables can be set only once (usually during manufacturing of
4906 the board). U-Boot refuses to delete or overwrite these variables
4907 once they have been set once.
4910 Further special Environment Variables:
4912 ver - Contains the U-Boot version string as printed
4913 with the "version" command. This variable is
4914 readonly (see CONFIG_VERSION_VARIABLE).
4917 Please note that changes to some configuration parameters may take
4918 only effect after the next boot (yes, that's just like Windoze :-).
4921 Callback functions for environment variables:
4922 ---------------------------------------------
4924 For some environment variables, the behavior of u-boot needs to change
4925 when their values are changed. This functionality allows functions to
4926 be associated with arbitrary variables. On creation, overwrite, or
4927 deletion, the callback will provide the opportunity for some side
4928 effect to happen or for the change to be rejected.
4930 The callbacks are named and associated with a function using the
4931 U_BOOT_ENV_CALLBACK macro in your board or driver code.
4933 These callbacks are associated with variables in one of two ways. The
4934 static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC
4935 in the board configuration to a string that defines a list of
4936 associations. The list must be in the following format:
4938 entry = variable_name[:callback_name]
4941 If the callback name is not specified, then the callback is deleted.
4942 Spaces are also allowed anywhere in the list.
4944 Callbacks can also be associated by defining the ".callbacks" variable
4945 with the same list format above. Any association in ".callbacks" will
4946 override any association in the static list. You can define
4947 CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the
4948 ".callbacks" environment variable in the default or embedded environment.
4950 If CONFIG_REGEX is defined, the variable_name above is evaluated as a
4951 regular expression. This allows multiple variables to be connected to
4952 the same callback without explicitly listing them all out.
4955 Command Line Parsing:
4956 =====================
4958 There are two different command line parsers available with U-Boot:
4959 the old "simple" one, and the much more powerful "hush" shell:
4961 Old, simple command line parser:
4962 --------------------------------
4964 - supports environment variables (through setenv / saveenv commands)
4965 - several commands on one line, separated by ';'
4966 - variable substitution using "... ${name} ..." syntax
4967 - special characters ('$', ';') can be escaped by prefixing with '\',
4969 setenv bootcmd bootm \${address}
4970 - You can also escape text by enclosing in single apostrophes, for example:
4971 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
4976 - similar to Bourne shell, with control structures like
4977 if...then...else...fi, for...do...done; while...do...done,
4978 until...do...done, ...
4979 - supports environment ("global") variables (through setenv / saveenv
4980 commands) and local shell variables (through standard shell syntax
4981 "name=value"); only environment variables can be used with "run"
4987 (1) If a command line (or an environment variable executed by a "run"
4988 command) contains several commands separated by semicolon, and
4989 one of these commands fails, then the remaining commands will be
4992 (2) If you execute several variables with one call to run (i. e.
4993 calling run with a list of variables as arguments), any failing
4994 command will cause "run" to terminate, i. e. the remaining
4995 variables are not executed.
4997 Note for Redundant Ethernet Interfaces:
4998 =======================================
5000 Some boards come with redundant Ethernet interfaces; U-Boot supports
5001 such configurations and is capable of automatic selection of a
5002 "working" interface when needed. MAC assignment works as follows:
5004 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
5005 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
5006 "eth1addr" (=>eth1), "eth2addr", ...
5008 If the network interface stores some valid MAC address (for instance
5009 in SROM), this is used as default address if there is NO correspon-
5010 ding setting in the environment; if the corresponding environment
5011 variable is set, this overrides the settings in the card; that means:
5013 o If the SROM has a valid MAC address, and there is no address in the
5014 environment, the SROM's address is used.
5016 o If there is no valid address in the SROM, and a definition in the
5017 environment exists, then the value from the environment variable is
5020 o If both the SROM and the environment contain a MAC address, and
5021 both addresses are the same, this MAC address is used.
5023 o If both the SROM and the environment contain a MAC address, and the
5024 addresses differ, the value from the environment is used and a
5027 o If neither SROM nor the environment contain a MAC address, an error
5028 is raised. If CONFIG_NET_RANDOM_ETHADDR is defined, then in this case
5029 a random, locally-assigned MAC is used.
5031 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
5032 will be programmed into hardware as part of the initialization process. This
5033 may be skipped by setting the appropriate 'ethmacskip' environment variable.
5034 The naming convention is as follows:
5035 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
5040 U-Boot is capable of booting (and performing other auxiliary operations on)
5041 images in two formats:
5043 New uImage format (FIT)
5044 -----------------------
5046 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
5047 to Flattened Device Tree). It allows the use of images with multiple
5048 components (several kernels, ramdisks, etc.), with contents protected by
5049 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
5055 Old image format is based on binary files which can be basically anything,
5056 preceded by a special header; see the definitions in include/image.h for
5057 details; basically, the header defines the following image properties:
5059 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
5060 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
5061 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
5062 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
5064 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
5065 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
5066 Currently supported: ARM, AVR32, Intel x86, MIPS, NDS32, Nios II, PowerPC).
5067 * Compression Type (uncompressed, gzip, bzip2)
5073 The header is marked by a special Magic Number, and both the header
5074 and the data portions of the image are secured against corruption by
5081 Although U-Boot should support any OS or standalone application
5082 easily, the main focus has always been on Linux during the design of
5085 U-Boot includes many features that so far have been part of some
5086 special "boot loader" code within the Linux kernel. Also, any
5087 "initrd" images to be used are no longer part of one big Linux image;
5088 instead, kernel and "initrd" are separate images. This implementation
5089 serves several purposes:
5091 - the same features can be used for other OS or standalone
5092 applications (for instance: using compressed images to reduce the
5093 Flash memory footprint)
5095 - it becomes much easier to port new Linux kernel versions because
5096 lots of low-level, hardware dependent stuff are done by U-Boot
5098 - the same Linux kernel image can now be used with different "initrd"
5099 images; of course this also means that different kernel images can
5100 be run with the same "initrd". This makes testing easier (you don't
5101 have to build a new "zImage.initrd" Linux image when you just
5102 change a file in your "initrd"). Also, a field-upgrade of the
5103 software is easier now.
5109 Porting Linux to U-Boot based systems:
5110 ---------------------------------------
5112 U-Boot cannot save you from doing all the necessary modifications to
5113 configure the Linux device drivers for use with your target hardware
5114 (no, we don't intend to provide a full virtual machine interface to
5117 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
5119 Just make sure your machine specific header file (for instance
5120 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
5121 Information structure as we define in include/asm-<arch>/u-boot.h,
5122 and make sure that your definition of IMAP_ADDR uses the same value
5123 as your U-Boot configuration in CONFIG_SYS_IMMR.
5125 Note that U-Boot now has a driver model, a unified model for drivers.
5126 If you are adding a new driver, plumb it into driver model. If there
5127 is no uclass available, you are encouraged to create one. See
5131 Configuring the Linux kernel:
5132 -----------------------------
5134 No specific requirements for U-Boot. Make sure you have some root
5135 device (initial ramdisk, NFS) for your target system.
5138 Building a Linux Image:
5139 -----------------------
5141 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
5142 not used. If you use recent kernel source, a new build target
5143 "uImage" will exist which automatically builds an image usable by
5144 U-Boot. Most older kernels also have support for a "pImage" target,
5145 which was introduced for our predecessor project PPCBoot and uses a
5146 100% compatible format.
5150 make TQM850L_defconfig
5155 The "uImage" build target uses a special tool (in 'tools/mkimage') to
5156 encapsulate a compressed Linux kernel image with header information,
5157 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
5159 * build a standard "vmlinux" kernel image (in ELF binary format):
5161 * convert the kernel into a raw binary image:
5163 ${CROSS_COMPILE}-objcopy -O binary \
5164 -R .note -R .comment \
5165 -S vmlinux linux.bin
5167 * compress the binary image:
5171 * package compressed binary image for U-Boot:
5173 mkimage -A ppc -O linux -T kernel -C gzip \
5174 -a 0 -e 0 -n "Linux Kernel Image" \
5175 -d linux.bin.gz uImage
5178 The "mkimage" tool can also be used to create ramdisk images for use
5179 with U-Boot, either separated from the Linux kernel image, or
5180 combined into one file. "mkimage" encapsulates the images with a 64
5181 byte header containing information about target architecture,
5182 operating system, image type, compression method, entry points, time
5183 stamp, CRC32 checksums, etc.
5185 "mkimage" can be called in two ways: to verify existing images and
5186 print the header information, or to build new images.
5188 In the first form (with "-l" option) mkimage lists the information
5189 contained in the header of an existing U-Boot image; this includes
5190 checksum verification:
5192 tools/mkimage -l image
5193 -l ==> list image header information
5195 The second form (with "-d" option) is used to build a U-Boot image
5196 from a "data file" which is used as image payload:
5198 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
5199 -n name -d data_file image
5200 -A ==> set architecture to 'arch'
5201 -O ==> set operating system to 'os'
5202 -T ==> set image type to 'type'
5203 -C ==> set compression type 'comp'
5204 -a ==> set load address to 'addr' (hex)
5205 -e ==> set entry point to 'ep' (hex)
5206 -n ==> set image name to 'name'
5207 -d ==> use image data from 'datafile'
5209 Right now, all Linux kernels for PowerPC systems use the same load
5210 address (0x00000000), but the entry point address depends on the
5213 - 2.2.x kernels have the entry point at 0x0000000C,
5214 - 2.3.x and later kernels have the entry point at 0x00000000.
5216 So a typical call to build a U-Boot image would read:
5218 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5219 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
5220 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
5221 > examples/uImage.TQM850L
5222 Image Name: 2.4.4 kernel for TQM850L
5223 Created: Wed Jul 19 02:34:59 2000
5224 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5225 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5226 Load Address: 0x00000000
5227 Entry Point: 0x00000000
5229 To verify the contents of the image (or check for corruption):
5231 -> tools/mkimage -l examples/uImage.TQM850L
5232 Image Name: 2.4.4 kernel for TQM850L
5233 Created: Wed Jul 19 02:34:59 2000
5234 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5235 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5236 Load Address: 0x00000000
5237 Entry Point: 0x00000000
5239 NOTE: for embedded systems where boot time is critical you can trade
5240 speed for memory and install an UNCOMPRESSED image instead: this
5241 needs more space in Flash, but boots much faster since it does not
5242 need to be uncompressed:
5244 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
5245 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5246 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
5247 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
5248 > examples/uImage.TQM850L-uncompressed
5249 Image Name: 2.4.4 kernel for TQM850L
5250 Created: Wed Jul 19 02:34:59 2000
5251 Image Type: PowerPC Linux Kernel Image (uncompressed)
5252 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
5253 Load Address: 0x00000000
5254 Entry Point: 0x00000000
5257 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
5258 when your kernel is intended to use an initial ramdisk:
5260 -> tools/mkimage -n 'Simple Ramdisk Image' \
5261 > -A ppc -O linux -T ramdisk -C gzip \
5262 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
5263 Image Name: Simple Ramdisk Image
5264 Created: Wed Jan 12 14:01:50 2000
5265 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5266 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
5267 Load Address: 0x00000000
5268 Entry Point: 0x00000000
5270 The "dumpimage" is a tool to disassemble images built by mkimage. Its "-i"
5271 option performs the converse operation of the mkimage's second form (the "-d"
5272 option). Given an image built by mkimage, the dumpimage extracts a "data file"
5275 tools/dumpimage -i image -T type -p position data_file
5276 -i ==> extract from the 'image' a specific 'data_file'
5277 -T ==> set image type to 'type'
5278 -p ==> 'position' (starting at 0) of the 'data_file' inside the 'image'
5281 Installing a Linux Image:
5282 -------------------------
5284 To downloading a U-Boot image over the serial (console) interface,
5285 you must convert the image to S-Record format:
5287 objcopy -I binary -O srec examples/image examples/image.srec
5289 The 'objcopy' does not understand the information in the U-Boot
5290 image header, so the resulting S-Record file will be relative to
5291 address 0x00000000. To load it to a given address, you need to
5292 specify the target address as 'offset' parameter with the 'loads'
5295 Example: install the image to address 0x40100000 (which on the
5296 TQM8xxL is in the first Flash bank):
5298 => erase 40100000 401FFFFF
5304 ## Ready for S-Record download ...
5305 ~>examples/image.srec
5306 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
5308 15989 15990 15991 15992
5309 [file transfer complete]
5311 ## Start Addr = 0x00000000
5314 You can check the success of the download using the 'iminfo' command;
5315 this includes a checksum verification so you can be sure no data
5316 corruption happened:
5320 ## Checking Image at 40100000 ...
5321 Image Name: 2.2.13 for initrd on TQM850L
5322 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5323 Data Size: 335725 Bytes = 327 kB = 0 MB
5324 Load Address: 00000000
5325 Entry Point: 0000000c
5326 Verifying Checksum ... OK
5332 The "bootm" command is used to boot an application that is stored in
5333 memory (RAM or Flash). In case of a Linux kernel image, the contents
5334 of the "bootargs" environment variable is passed to the kernel as
5335 parameters. You can check and modify this variable using the
5336 "printenv" and "setenv" commands:
5339 => printenv bootargs
5340 bootargs=root=/dev/ram
5342 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5344 => printenv bootargs
5345 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5348 ## Booting Linux kernel at 40020000 ...
5349 Image Name: 2.2.13 for NFS on TQM850L
5350 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5351 Data Size: 381681 Bytes = 372 kB = 0 MB
5352 Load Address: 00000000
5353 Entry Point: 0000000c
5354 Verifying Checksum ... OK
5355 Uncompressing Kernel Image ... OK
5356 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
5357 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5358 time_init: decrementer frequency = 187500000/60
5359 Calibrating delay loop... 49.77 BogoMIPS
5360 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
5363 If you want to boot a Linux kernel with initial RAM disk, you pass
5364 the memory addresses of both the kernel and the initrd image (PPBCOOT
5365 format!) to the "bootm" command:
5367 => imi 40100000 40200000
5369 ## Checking Image at 40100000 ...
5370 Image Name: 2.2.13 for initrd on TQM850L
5371 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5372 Data Size: 335725 Bytes = 327 kB = 0 MB
5373 Load Address: 00000000
5374 Entry Point: 0000000c
5375 Verifying Checksum ... OK
5377 ## Checking Image at 40200000 ...
5378 Image Name: Simple Ramdisk Image
5379 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5380 Data Size: 566530 Bytes = 553 kB = 0 MB
5381 Load Address: 00000000
5382 Entry Point: 00000000
5383 Verifying Checksum ... OK
5385 => bootm 40100000 40200000
5386 ## Booting Linux kernel at 40100000 ...
5387 Image Name: 2.2.13 for initrd on TQM850L
5388 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5389 Data Size: 335725 Bytes = 327 kB = 0 MB
5390 Load Address: 00000000
5391 Entry Point: 0000000c
5392 Verifying Checksum ... OK
5393 Uncompressing Kernel Image ... OK
5394 ## Loading RAMDisk Image at 40200000 ...
5395 Image Name: Simple Ramdisk Image
5396 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5397 Data Size: 566530 Bytes = 553 kB = 0 MB
5398 Load Address: 00000000
5399 Entry Point: 00000000
5400 Verifying Checksum ... OK
5401 Loading Ramdisk ... OK
5402 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
5403 Boot arguments: root=/dev/ram
5404 time_init: decrementer frequency = 187500000/60
5405 Calibrating delay loop... 49.77 BogoMIPS
5407 RAMDISK: Compressed image found at block 0
5408 VFS: Mounted root (ext2 filesystem).
5412 Boot Linux and pass a flat device tree:
5415 First, U-Boot must be compiled with the appropriate defines. See the section
5416 titled "Linux Kernel Interface" above for a more in depth explanation. The
5417 following is an example of how to start a kernel and pass an updated
5423 oft=oftrees/mpc8540ads.dtb
5424 => tftp $oftaddr $oft
5425 Speed: 1000, full duplex
5427 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
5428 Filename 'oftrees/mpc8540ads.dtb'.
5429 Load address: 0x300000
5432 Bytes transferred = 4106 (100a hex)
5433 => tftp $loadaddr $bootfile
5434 Speed: 1000, full duplex
5436 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
5438 Load address: 0x200000
5439 Loading:############
5441 Bytes transferred = 1029407 (fb51f hex)
5446 => bootm $loadaddr - $oftaddr
5447 ## Booting image at 00200000 ...
5448 Image Name: Linux-2.6.17-dirty
5449 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5450 Data Size: 1029343 Bytes = 1005.2 kB
5451 Load Address: 00000000
5452 Entry Point: 00000000
5453 Verifying Checksum ... OK
5454 Uncompressing Kernel Image ... OK
5455 Booting using flat device tree at 0x300000
5456 Using MPC85xx ADS machine description
5457 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
5461 More About U-Boot Image Types:
5462 ------------------------------
5464 U-Boot supports the following image types:
5466 "Standalone Programs" are directly runnable in the environment
5467 provided by U-Boot; it is expected that (if they behave
5468 well) you can continue to work in U-Boot after return from
5469 the Standalone Program.
5470 "OS Kernel Images" are usually images of some Embedded OS which
5471 will take over control completely. Usually these programs
5472 will install their own set of exception handlers, device
5473 drivers, set up the MMU, etc. - this means, that you cannot
5474 expect to re-enter U-Boot except by resetting the CPU.
5475 "RAMDisk Images" are more or less just data blocks, and their
5476 parameters (address, size) are passed to an OS kernel that is
5478 "Multi-File Images" contain several images, typically an OS
5479 (Linux) kernel image and one or more data images like
5480 RAMDisks. This construct is useful for instance when you want
5481 to boot over the network using BOOTP etc., where the boot
5482 server provides just a single image file, but you want to get
5483 for instance an OS kernel and a RAMDisk image.
5485 "Multi-File Images" start with a list of image sizes, each
5486 image size (in bytes) specified by an "uint32_t" in network
5487 byte order. This list is terminated by an "(uint32_t)0".
5488 Immediately after the terminating 0 follow the images, one by
5489 one, all aligned on "uint32_t" boundaries (size rounded up to
5490 a multiple of 4 bytes).
5492 "Firmware Images" are binary images containing firmware (like
5493 U-Boot or FPGA images) which usually will be programmed to
5496 "Script files" are command sequences that will be executed by
5497 U-Boot's command interpreter; this feature is especially
5498 useful when you configure U-Boot to use a real shell (hush)
5499 as command interpreter.
5501 Booting the Linux zImage:
5502 -------------------------
5504 On some platforms, it's possible to boot Linux zImage. This is done
5505 using the "bootz" command. The syntax of "bootz" command is the same
5506 as the syntax of "bootm" command.
5508 Note, defining the CONFIG_SUPPORT_RAW_INITRD allows user to supply
5509 kernel with raw initrd images. The syntax is slightly different, the
5510 address of the initrd must be augmented by it's size, in the following
5511 format: "<initrd addres>:<initrd size>".
5517 One of the features of U-Boot is that you can dynamically load and
5518 run "standalone" applications, which can use some resources of
5519 U-Boot like console I/O functions or interrupt services.
5521 Two simple examples are included with the sources:
5526 'examples/hello_world.c' contains a small "Hello World" Demo
5527 application; it is automatically compiled when you build U-Boot.
5528 It's configured to run at address 0x00040004, so you can play with it
5532 ## Ready for S-Record download ...
5533 ~>examples/hello_world.srec
5534 1 2 3 4 5 6 7 8 9 10 11 ...
5535 [file transfer complete]
5537 ## Start Addr = 0x00040004
5539 => go 40004 Hello World! This is a test.
5540 ## Starting application at 0x00040004 ...
5551 Hit any key to exit ...
5553 ## Application terminated, rc = 0x0
5555 Another example, which demonstrates how to register a CPM interrupt
5556 handler with the U-Boot code, can be found in 'examples/timer.c'.
5557 Here, a CPM timer is set up to generate an interrupt every second.
5558 The interrupt service routine is trivial, just printing a '.'
5559 character, but this is just a demo program. The application can be
5560 controlled by the following keys:
5562 ? - print current values og the CPM Timer registers
5563 b - enable interrupts and start timer
5564 e - stop timer and disable interrupts
5565 q - quit application
5568 ## Ready for S-Record download ...
5569 ~>examples/timer.srec
5570 1 2 3 4 5 6 7 8 9 10 11 ...
5571 [file transfer complete]
5573 ## Start Addr = 0x00040004
5576 ## Starting application at 0x00040004 ...
5579 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
5582 [q, b, e, ?] Set interval 1000000 us
5585 [q, b, e, ?] ........
5586 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
5589 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
5592 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
5595 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
5597 [q, b, e, ?] ...Stopping timer
5599 [q, b, e, ?] ## Application terminated, rc = 0x0
5605 Over time, many people have reported problems when trying to use the
5606 "minicom" terminal emulation program for serial download. I (wd)
5607 consider minicom to be broken, and recommend not to use it. Under
5608 Unix, I recommend to use C-Kermit for general purpose use (and
5609 especially for kermit binary protocol download ("loadb" command), and
5610 use "cu" for S-Record download ("loads" command). See
5611 http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
5612 for help with kermit.
5615 Nevertheless, if you absolutely want to use it try adding this
5616 configuration to your "File transfer protocols" section:
5618 Name Program Name U/D FullScr IO-Red. Multi
5619 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
5620 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
5626 Starting at version 0.9.2, U-Boot supports NetBSD both as host
5627 (build U-Boot) and target system (boots NetBSD/mpc8xx).
5629 Building requires a cross environment; it is known to work on
5630 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
5631 need gmake since the Makefiles are not compatible with BSD make).
5632 Note that the cross-powerpc package does not install include files;
5633 attempting to build U-Boot will fail because <machine/ansi.h> is
5634 missing. This file has to be installed and patched manually:
5636 # cd /usr/pkg/cross/powerpc-netbsd/include
5638 # ln -s powerpc machine
5639 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
5640 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
5642 Native builds *don't* work due to incompatibilities between native
5643 and U-Boot include files.
5645 Booting assumes that (the first part of) the image booted is a
5646 stage-2 loader which in turn loads and then invokes the kernel
5647 proper. Loader sources will eventually appear in the NetBSD source
5648 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
5649 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
5652 Implementation Internals:
5653 =========================
5655 The following is not intended to be a complete description of every
5656 implementation detail. However, it should help to understand the
5657 inner workings of U-Boot and make it easier to port it to custom
5661 Initial Stack, Global Data:
5662 ---------------------------
5664 The implementation of U-Boot is complicated by the fact that U-Boot
5665 starts running out of ROM (flash memory), usually without access to
5666 system RAM (because the memory controller is not initialized yet).
5667 This means that we don't have writable Data or BSS segments, and BSS
5668 is not initialized as zero. To be able to get a C environment working
5669 at all, we have to allocate at least a minimal stack. Implementation
5670 options for this are defined and restricted by the CPU used: Some CPU
5671 models provide on-chip memory (like the IMMR area on MPC8xx and
5672 MPC826x processors), on others (parts of) the data cache can be
5673 locked as (mis-) used as memory, etc.
5675 Chris Hallinan posted a good summary of these issues to the
5676 U-Boot mailing list:
5678 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
5679 From: "Chris Hallinan" <clh@net1plus.com>
5680 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
5683 Correct me if I'm wrong, folks, but the way I understand it
5684 is this: Using DCACHE as initial RAM for Stack, etc, does not
5685 require any physical RAM backing up the cache. The cleverness
5686 is that the cache is being used as a temporary supply of
5687 necessary storage before the SDRAM controller is setup. It's
5688 beyond the scope of this list to explain the details, but you
5689 can see how this works by studying the cache architecture and
5690 operation in the architecture and processor-specific manuals.
5692 OCM is On Chip Memory, which I believe the 405GP has 4K. It
5693 is another option for the system designer to use as an
5694 initial stack/RAM area prior to SDRAM being available. Either
5695 option should work for you. Using CS 4 should be fine if your
5696 board designers haven't used it for something that would
5697 cause you grief during the initial boot! It is frequently not
5700 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
5701 with your processor/board/system design. The default value
5702 you will find in any recent u-boot distribution in
5703 walnut.h should work for you. I'd set it to a value larger
5704 than your SDRAM module. If you have a 64MB SDRAM module, set
5705 it above 400_0000. Just make sure your board has no resources
5706 that are supposed to respond to that address! That code in
5707 start.S has been around a while and should work as is when
5708 you get the config right.
5713 It is essential to remember this, since it has some impact on the C
5714 code for the initialization procedures:
5716 * Initialized global data (data segment) is read-only. Do not attempt
5719 * Do not use any uninitialized global data (or implicitly initialized
5720 as zero data - BSS segment) at all - this is undefined, initiali-
5721 zation is performed later (when relocating to RAM).
5723 * Stack space is very limited. Avoid big data buffers or things like
5726 Having only the stack as writable memory limits means we cannot use
5727 normal global data to share information between the code. But it
5728 turned out that the implementation of U-Boot can be greatly
5729 simplified by making a global data structure (gd_t) available to all
5730 functions. We could pass a pointer to this data as argument to _all_
5731 functions, but this would bloat the code. Instead we use a feature of
5732 the GCC compiler (Global Register Variables) to share the data: we
5733 place a pointer (gd) to the global data into a register which we
5734 reserve for this purpose.
5736 When choosing a register for such a purpose we are restricted by the
5737 relevant (E)ABI specifications for the current architecture, and by
5738 GCC's implementation.
5740 For PowerPC, the following registers have specific use:
5742 R2: reserved for system use
5743 R3-R4: parameter passing and return values
5744 R5-R10: parameter passing
5745 R13: small data area pointer
5749 (U-Boot also uses R12 as internal GOT pointer. r12
5750 is a volatile register so r12 needs to be reset when
5751 going back and forth between asm and C)
5753 ==> U-Boot will use R2 to hold a pointer to the global data
5755 Note: on PPC, we could use a static initializer (since the
5756 address of the global data structure is known at compile time),
5757 but it turned out that reserving a register results in somewhat
5758 smaller code - although the code savings are not that big (on
5759 average for all boards 752 bytes for the whole U-Boot image,
5760 624 text + 127 data).
5762 On ARM, the following registers are used:
5764 R0: function argument word/integer result
5765 R1-R3: function argument word
5766 R9: platform specific
5767 R10: stack limit (used only if stack checking is enabled)
5768 R11: argument (frame) pointer
5769 R12: temporary workspace
5772 R15: program counter
5774 ==> U-Boot will use R9 to hold a pointer to the global data
5776 Note: on ARM, only R_ARM_RELATIVE relocations are supported.
5778 On Nios II, the ABI is documented here:
5779 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
5781 ==> U-Boot will use gp to hold a pointer to the global data
5783 Note: on Nios II, we give "-G0" option to gcc and don't use gp
5784 to access small data sections, so gp is free.
5786 On NDS32, the following registers are used:
5788 R0-R1: argument/return
5790 R15: temporary register for assembler
5791 R16: trampoline register
5792 R28: frame pointer (FP)
5793 R29: global pointer (GP)
5794 R30: link register (LP)
5795 R31: stack pointer (SP)
5796 PC: program counter (PC)
5798 ==> U-Boot will use R10 to hold a pointer to the global data
5800 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
5801 or current versions of GCC may "optimize" the code too much.
5806 U-Boot runs in system state and uses physical addresses, i.e. the
5807 MMU is not used either for address mapping nor for memory protection.
5809 The available memory is mapped to fixed addresses using the memory
5810 controller. In this process, a contiguous block is formed for each
5811 memory type (Flash, SDRAM, SRAM), even when it consists of several
5812 physical memory banks.
5814 U-Boot is installed in the first 128 kB of the first Flash bank (on
5815 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
5816 booting and sizing and initializing DRAM, the code relocates itself
5817 to the upper end of DRAM. Immediately below the U-Boot code some
5818 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
5819 configuration setting]. Below that, a structure with global Board
5820 Info data is placed, followed by the stack (growing downward).
5822 Additionally, some exception handler code is copied to the low 8 kB
5823 of DRAM (0x00000000 ... 0x00001FFF).
5825 So a typical memory configuration with 16 MB of DRAM could look like
5828 0x0000 0000 Exception Vector code
5831 0x0000 2000 Free for Application Use
5837 0x00FB FF20 Monitor Stack (Growing downward)
5838 0x00FB FFAC Board Info Data and permanent copy of global data
5839 0x00FC 0000 Malloc Arena
5842 0x00FE 0000 RAM Copy of Monitor Code
5843 ... eventually: LCD or video framebuffer
5844 ... eventually: pRAM (Protected RAM - unchanged by reset)
5845 0x00FF FFFF [End of RAM]
5848 System Initialization:
5849 ----------------------
5851 In the reset configuration, U-Boot starts at the reset entry point
5852 (on most PowerPC systems at address 0x00000100). Because of the reset
5853 configuration for CS0# this is a mirror of the on board Flash memory.
5854 To be able to re-map memory U-Boot then jumps to its link address.
5855 To be able to implement the initialization code in C, a (small!)
5856 initial stack is set up in the internal Dual Ported RAM (in case CPUs
5857 which provide such a feature like MPC8xx or MPC8260), or in a locked
5858 part of the data cache. After that, U-Boot initializes the CPU core,
5859 the caches and the SIU.
5861 Next, all (potentially) available memory banks are mapped using a
5862 preliminary mapping. For example, we put them on 512 MB boundaries
5863 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
5864 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
5865 programmed for SDRAM access. Using the temporary configuration, a
5866 simple memory test is run that determines the size of the SDRAM
5869 When there is more than one SDRAM bank, and the banks are of
5870 different size, the largest is mapped first. For equal size, the first
5871 bank (CS2#) is mapped first. The first mapping is always for address
5872 0x00000000, with any additional banks following immediately to create
5873 contiguous memory starting from 0.
5875 Then, the monitor installs itself at the upper end of the SDRAM area
5876 and allocates memory for use by malloc() and for the global Board
5877 Info data; also, the exception vector code is copied to the low RAM
5878 pages, and the final stack is set up.
5880 Only after this relocation will you have a "normal" C environment;
5881 until that you are restricted in several ways, mostly because you are
5882 running from ROM, and because the code will have to be relocated to a
5886 U-Boot Porting Guide:
5887 ----------------------
5889 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
5893 int main(int argc, char *argv[])
5895 sighandler_t no_more_time;
5897 signal(SIGALRM, no_more_time);
5898 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
5900 if (available_money > available_manpower) {
5901 Pay consultant to port U-Boot;
5905 Download latest U-Boot source;
5907 Subscribe to u-boot mailing list;
5910 email("Hi, I am new to U-Boot, how do I get started?");
5913 Read the README file in the top level directory;
5914 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
5915 Read applicable doc/*.README;
5916 Read the source, Luke;
5917 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
5920 if (available_money > toLocalCurrency ($2500))
5923 Add a lot of aggravation and time;
5925 if (a similar board exists) { /* hopefully... */
5926 cp -a board/<similar> board/<myboard>
5927 cp include/configs/<similar>.h include/configs/<myboard>.h
5929 Create your own board support subdirectory;
5930 Create your own board include/configs/<myboard>.h file;
5932 Edit new board/<myboard> files
5933 Edit new include/configs/<myboard>.h
5938 Add / modify source code;
5942 email("Hi, I am having problems...");
5944 Send patch file to the U-Boot email list;
5945 if (reasonable critiques)
5946 Incorporate improvements from email list code review;
5948 Defend code as written;
5954 void no_more_time (int sig)
5963 All contributions to U-Boot should conform to the Linux kernel
5964 coding style; see the file "Documentation/CodingStyle" and the script
5965 "scripts/Lindent" in your Linux kernel source directory.
5967 Source files originating from a different project (for example the
5968 MTD subsystem) are generally exempt from these guidelines and are not
5969 reformatted to ease subsequent migration to newer versions of those
5972 Please note that U-Boot is implemented in C (and to some small parts in
5973 Assembler); no C++ is used, so please do not use C++ style comments (//)
5976 Please also stick to the following formatting rules:
5977 - remove any trailing white space
5978 - use TAB characters for indentation and vertical alignment, not spaces
5979 - make sure NOT to use DOS '\r\n' line feeds
5980 - do not add more than 2 consecutive empty lines to source files
5981 - do not add trailing empty lines to source files
5983 Submissions which do not conform to the standards may be returned
5984 with a request to reformat the changes.
5990 Since the number of patches for U-Boot is growing, we need to
5991 establish some rules. Submissions which do not conform to these rules
5992 may be rejected, even when they contain important and valuable stuff.
5994 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
5996 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
5997 see http://lists.denx.de/mailman/listinfo/u-boot
5999 When you send a patch, please include the following information with
6002 * For bug fixes: a description of the bug and how your patch fixes
6003 this bug. Please try to include a way of demonstrating that the
6004 patch actually fixes something.
6006 * For new features: a description of the feature and your
6009 * A CHANGELOG entry as plaintext (separate from the patch)
6011 * For major contributions, add a MAINTAINERS file with your
6012 information and associated file and directory references.
6014 * When you add support for a new board, don't forget to add a
6015 maintainer e-mail address to the boards.cfg file, too.
6017 * If your patch adds new configuration options, don't forget to
6018 document these in the README file.
6020 * The patch itself. If you are using git (which is *strongly*
6021 recommended) you can easily generate the patch using the
6022 "git format-patch". If you then use "git send-email" to send it to
6023 the U-Boot mailing list, you will avoid most of the common problems
6024 with some other mail clients.
6026 If you cannot use git, use "diff -purN OLD NEW". If your version of
6027 diff does not support these options, then get the latest version of
6030 The current directory when running this command shall be the parent
6031 directory of the U-Boot source tree (i. e. please make sure that
6032 your patch includes sufficient directory information for the
6035 We prefer patches as plain text. MIME attachments are discouraged,
6036 and compressed attachments must not be used.
6038 * If one logical set of modifications affects or creates several
6039 files, all these changes shall be submitted in a SINGLE patch file.
6041 * Changesets that contain different, unrelated modifications shall be
6042 submitted as SEPARATE patches, one patch per changeset.
6047 * Before sending the patch, run the buildman script on your patched
6048 source tree and make sure that no errors or warnings are reported
6049 for any of the boards.
6051 * Keep your modifications to the necessary minimum: A patch
6052 containing several unrelated changes or arbitrary reformats will be
6053 returned with a request to re-formatting / split it.
6055 * If you modify existing code, make sure that your new code does not
6056 add to the memory footprint of the code ;-) Small is beautiful!
6057 When adding new features, these should compile conditionally only
6058 (using #ifdef), and the resulting code with the new feature
6059 disabled must not need more memory than the old code without your
6062 * Remember that there is a size limit of 100 kB per message on the
6063 u-boot mailing list. Bigger patches will be moderated. If they are
6064 reasonable and not too big, they will be acknowledged. But patches
6065 bigger than the size limit should be avoided.