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_GETTIME * Get time since boot
848 CONFIG_CMD_GO * the 'go' command (exec code)
849 CONFIG_CMD_GREPENV * search environment
850 CONFIG_CMD_HASH * calculate hash / digest
851 CONFIG_CMD_I2C * I2C serial bus support
852 CONFIG_CMD_IDE * IDE harddisk support
853 CONFIG_CMD_IMI iminfo
854 CONFIG_CMD_IMLS List all images found in NOR flash
855 CONFIG_CMD_IMLS_NAND * List all images found in NAND flash
856 CONFIG_CMD_IMMAP * IMMR dump support
857 CONFIG_CMD_IOTRACE * I/O tracing for debugging
858 CONFIG_CMD_IMPORTENV * import an environment
859 CONFIG_CMD_INI * import data from an ini file into the env
860 CONFIG_CMD_IRQ * irqinfo
861 CONFIG_CMD_ITEST Integer/string test of 2 values
862 CONFIG_CMD_JFFS2 * JFFS2 Support
863 CONFIG_CMD_KGDB * kgdb
864 CONFIG_CMD_LDRINFO * ldrinfo (display Blackfin loader)
865 CONFIG_CMD_LINK_LOCAL * link-local IP address auto-configuration
867 CONFIG_CMD_LOADB loadb
868 CONFIG_CMD_LOADS loads
869 CONFIG_CMD_MD5SUM * print md5 message digest
870 (requires CONFIG_CMD_MEMORY and CONFIG_MD5)
871 CONFIG_CMD_MEMINFO * Display detailed memory information
872 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
874 CONFIG_CMD_MEMTEST * mtest
875 CONFIG_CMD_MISC Misc functions like sleep etc
876 CONFIG_CMD_MMC * MMC memory mapped support
877 CONFIG_CMD_MII * MII utility commands
878 CONFIG_CMD_MTDPARTS * MTD partition support
879 CONFIG_CMD_NAND * NAND support
880 CONFIG_CMD_NET bootp, tftpboot, rarpboot
881 CONFIG_CMD_NFS NFS support
882 CONFIG_CMD_PCA953X * PCA953x I2C gpio commands
883 CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command
884 CONFIG_CMD_PCI * pciinfo
885 CONFIG_CMD_PCMCIA * PCMCIA support
886 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
888 CONFIG_CMD_PORTIO * Port I/O
889 CONFIG_CMD_READ * Read raw data from partition
890 CONFIG_CMD_REGINFO * Register dump
891 CONFIG_CMD_RUN run command in env variable
892 CONFIG_CMD_SANDBOX * sb command to access sandbox features
893 CONFIG_CMD_SAVES * save S record dump
894 CONFIG_SCSI * SCSI Support
895 CONFIG_CMD_SDRAM * print SDRAM configuration information
896 (requires CONFIG_CMD_I2C)
897 CONFIG_CMD_SETGETDCR Support for DCR Register access
899 CONFIG_CMD_SF * Read/write/erase SPI NOR flash
900 CONFIG_CMD_SHA1SUM * print sha1 memory digest
901 (requires CONFIG_CMD_MEMORY)
902 CONFIG_CMD_SOFTSWITCH * Soft switch setting command for BF60x
903 CONFIG_CMD_SOURCE "source" command Support
904 CONFIG_CMD_SPI * SPI serial bus support
905 CONFIG_CMD_TFTPSRV * TFTP transfer in server mode
906 CONFIG_CMD_TFTPPUT * TFTP put command (upload)
907 CONFIG_CMD_TIME * run command and report execution time (ARM specific)
908 CONFIG_CMD_TIMER * access to the system tick timer
909 CONFIG_CMD_USB * USB support
910 CONFIG_CMD_CDP * Cisco Discover Protocol support
911 CONFIG_CMD_MFSL * Microblaze FSL support
912 CONFIG_CMD_XIMG Load part of Multi Image
913 CONFIG_CMD_UUID * Generate random UUID or GUID string
915 EXAMPLE: If you want all functions except of network
916 support you can write:
918 #include "config_cmd_all.h"
919 #undef CONFIG_CMD_NET
922 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
924 Note: Don't enable the "icache" and "dcache" commands
925 (configuration option CONFIG_CMD_CACHE) unless you know
926 what you (and your U-Boot users) are doing. Data
927 cache cannot be enabled on systems like the 8xx or
928 8260 (where accesses to the IMMR region must be
929 uncached), and it cannot be disabled on all other
930 systems where we (mis-) use the data cache to hold an
931 initial stack and some data.
934 XXX - this list needs to get updated!
936 - Removal of commands
937 If no commands are needed to boot, you can disable
938 CONFIG_CMDLINE to remove them. In this case, the command line
939 will not be available, and when U-Boot wants to execute the
940 boot command (on start-up) it will call board_run_command()
941 instead. This can reduce image size significantly for very
942 simple boot procedures.
944 - Regular expression support:
946 If this variable is defined, U-Boot is linked against
947 the SLRE (Super Light Regular Expression) library,
948 which adds regex support to some commands, as for
949 example "env grep" and "setexpr".
953 If this variable is defined, U-Boot will use a device tree
954 to configure its devices, instead of relying on statically
955 compiled #defines in the board file. This option is
956 experimental and only available on a few boards. The device
957 tree is available in the global data as gd->fdt_blob.
959 U-Boot needs to get its device tree from somewhere. This can
960 be done using one of the three options below:
963 If this variable is defined, U-Boot will embed a device tree
964 binary in its image. This device tree file should be in the
965 board directory and called <soc>-<board>.dts. The binary file
966 is then picked up in board_init_f() and made available through
967 the global data structure as gd->blob.
970 If this variable is defined, U-Boot will build a device tree
971 binary. It will be called u-boot.dtb. Architecture-specific
972 code will locate it at run-time. Generally this works by:
974 cat u-boot.bin u-boot.dtb >image.bin
976 and in fact, U-Boot does this for you, creating a file called
977 u-boot-dtb.bin which is useful in the common case. You can
978 still use the individual files if you need something more
982 If this variable is defined, U-Boot will use the device tree
983 provided by the board at runtime instead of embedding one with
984 the image. Only boards defining board_fdt_blob_setup() support
985 this option (see include/fdtdec.h file).
989 If this variable is defined, it enables watchdog
990 support for the SoC. There must be support in the SoC
991 specific code for a watchdog. For the 8xx and 8260
992 CPUs, the SIU Watchdog feature is enabled in the SYPCR
993 register. When supported for a specific SoC is
994 available, then no further board specific code should
998 When using a watchdog circuitry external to the used
999 SoC, then define this variable and provide board
1000 specific code for the "hw_watchdog_reset" function.
1002 CONFIG_AT91_HW_WDT_TIMEOUT
1003 specify the timeout in seconds. default 2 seconds.
1006 CONFIG_VERSION_VARIABLE
1007 If this variable is defined, an environment variable
1008 named "ver" is created by U-Boot showing the U-Boot
1009 version as printed by the "version" command.
1010 Any change to this variable will be reverted at the
1015 When CONFIG_CMD_DATE is selected, the type of the RTC
1016 has to be selected, too. Define exactly one of the
1019 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
1020 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
1021 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC
1022 CONFIG_RTC_MC146818 - use MC146818 RTC
1023 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
1024 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
1025 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
1026 CONFIG_RTC_DS1339 - use Maxim, Inc. DS1339 RTC
1027 CONFIG_RTC_DS164x - use Dallas DS164x RTC
1028 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
1029 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
1030 CONFIG_SYS_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
1031 CONFIG_SYS_RV3029_TCR - enable trickle charger on
1034 Note that if the RTC uses I2C, then the I2C interface
1035 must also be configured. See I2C Support, below.
1038 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
1040 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
1041 chip-ngpio pairs that tell the PCA953X driver the number of
1042 pins supported by a particular chip.
1044 Note that if the GPIO device uses I2C, then the I2C interface
1045 must also be configured. See I2C Support, below.
1048 When CONFIG_IO_TRACE is selected, U-Boot intercepts all I/O
1049 accesses and can checksum them or write a list of them out
1050 to memory. See the 'iotrace' command for details. This is
1051 useful for testing device drivers since it can confirm that
1052 the driver behaves the same way before and after a code
1053 change. Currently this is supported on sandbox and arm. To
1054 add support for your architecture, add '#include <iotrace.h>'
1055 to the bottom of arch/<arch>/include/asm/io.h and test.
1057 Example output from the 'iotrace stats' command is below.
1058 Note that if the trace buffer is exhausted, the checksum will
1059 still continue to operate.
1062 Start: 10000000 (buffer start address)
1063 Size: 00010000 (buffer size)
1064 Offset: 00000120 (current buffer offset)
1065 Output: 10000120 (start + offset)
1066 Count: 00000018 (number of trace records)
1067 CRC32: 9526fb66 (CRC32 of all trace records)
1069 - Timestamp Support:
1071 When CONFIG_TIMESTAMP is selected, the timestamp
1072 (date and time) of an image is printed by image
1073 commands like bootm or iminfo. This option is
1074 automatically enabled when you select CONFIG_CMD_DATE .
1076 - Partition Labels (disklabels) Supported:
1077 Zero or more of the following:
1078 CONFIG_MAC_PARTITION Apple's MacOS partition table.
1079 CONFIG_DOS_PARTITION MS Dos partition table, traditional on the
1080 Intel architecture, USB sticks, etc.
1081 CONFIG_ISO_PARTITION ISO partition table, used on CDROM etc.
1082 CONFIG_EFI_PARTITION GPT partition table, common when EFI is the
1083 bootloader. Note 2TB partition limit; see
1085 CONFIG_MTD_PARTITIONS Memory Technology Device partition table.
1087 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
1088 CONFIG_SCSI) you must configure support for at
1089 least one non-MTD partition type as well.
1092 CONFIG_IDE_RESET_ROUTINE - this is defined in several
1093 board configurations files but used nowhere!
1095 CONFIG_IDE_RESET - is this is defined, IDE Reset will
1096 be performed by calling the function
1097 ide_set_reset(int reset)
1098 which has to be defined in a board specific file
1103 Set this to enable ATAPI support.
1108 Set this to enable support for disks larger than 137GB
1109 Also look at CONFIG_SYS_64BIT_LBA.
1110 Whithout these , LBA48 support uses 32bit variables and will 'only'
1111 support disks up to 2.1TB.
1113 CONFIG_SYS_64BIT_LBA:
1114 When enabled, makes the IDE subsystem use 64bit sector addresses.
1118 At the moment only there is only support for the
1119 SYM53C8XX SCSI controller; define
1120 CONFIG_SCSI_SYM53C8XX to enable it.
1122 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
1123 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
1124 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
1125 maximum numbers of LUNs, SCSI ID's and target
1127 CONFIG_SYS_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
1129 The environment variable 'scsidevs' is set to the number of
1130 SCSI devices found during the last scan.
1132 - NETWORK Support (PCI):
1134 Support for Intel 8254x/8257x gigabit chips.
1137 Utility code for direct access to the SPI bus on Intel 8257x.
1138 This does not do anything useful unless you set at least one
1139 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
1141 CONFIG_E1000_SPI_GENERIC
1142 Allow generic access to the SPI bus on the Intel 8257x, for
1143 example with the "sspi" command.
1146 Management command for E1000 devices. When used on devices
1147 with SPI support you can reprogram the EEPROM from U-Boot.
1150 Support for Intel 82557/82559/82559ER chips.
1151 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
1152 write routine for first time initialisation.
1155 Support for Digital 2114x chips.
1156 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
1157 modem chip initialisation (KS8761/QS6611).
1160 Support for National dp83815 chips.
1163 Support for National dp8382[01] gigabit chips.
1165 - NETWORK Support (other):
1167 CONFIG_DRIVER_AT91EMAC
1168 Support for AT91RM9200 EMAC.
1171 Define this to use reduced MII inteface
1173 CONFIG_DRIVER_AT91EMAC_QUIET
1174 If this defined, the driver is quiet.
1175 The driver doen't show link status messages.
1177 CONFIG_CALXEDA_XGMAC
1178 Support for the Calxeda XGMAC device
1181 Support for SMSC's LAN91C96 chips.
1183 CONFIG_LAN91C96_USE_32_BIT
1184 Define this to enable 32 bit addressing
1187 Support for SMSC's LAN91C111 chip
1189 CONFIG_SMC91111_BASE
1190 Define this to hold the physical address
1191 of the device (I/O space)
1193 CONFIG_SMC_USE_32_BIT
1194 Define this if data bus is 32 bits
1196 CONFIG_SMC_USE_IOFUNCS
1197 Define this to use i/o functions instead of macros
1198 (some hardware wont work with macros)
1200 CONFIG_DRIVER_TI_EMAC
1201 Support for davinci emac
1203 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
1204 Define this if you have more then 3 PHYs.
1207 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
1209 CONFIG_FTGMAC100_EGIGA
1210 Define this to use GE link update with gigabit PHY.
1211 Define this if FTGMAC100 is connected to gigabit PHY.
1212 If your system has 10/100 PHY only, it might not occur
1213 wrong behavior. Because PHY usually return timeout or
1214 useless data when polling gigabit status and gigabit
1215 control registers. This behavior won't affect the
1216 correctnessof 10/100 link speed update.
1219 Support for SMSC's LAN911x and LAN921x chips
1222 Define this to hold the physical address
1223 of the device (I/O space)
1225 CONFIG_SMC911X_32_BIT
1226 Define this if data bus is 32 bits
1228 CONFIG_SMC911X_16_BIT
1229 Define this if data bus is 16 bits. If your processor
1230 automatically converts one 32 bit word to two 16 bit
1231 words you may also try CONFIG_SMC911X_32_BIT.
1234 Support for Renesas on-chip Ethernet controller
1236 CONFIG_SH_ETHER_USE_PORT
1237 Define the number of ports to be used
1239 CONFIG_SH_ETHER_PHY_ADDR
1240 Define the ETH PHY's address
1242 CONFIG_SH_ETHER_CACHE_WRITEBACK
1243 If this option is set, the driver enables cache flush.
1247 Support for PWM module on the imx6.
1251 Support TPM devices.
1253 CONFIG_TPM_TIS_INFINEON
1254 Support for Infineon i2c bus TPM devices. Only one device
1255 per system is supported at this time.
1257 CONFIG_TPM_TIS_I2C_BURST_LIMITATION
1258 Define the burst count bytes upper limit
1261 Support for STMicroelectronics TPM devices. Requires DM_TPM support.
1263 CONFIG_TPM_ST33ZP24_I2C
1264 Support for STMicroelectronics ST33ZP24 I2C devices.
1265 Requires TPM_ST33ZP24 and I2C.
1267 CONFIG_TPM_ST33ZP24_SPI
1268 Support for STMicroelectronics ST33ZP24 SPI devices.
1269 Requires TPM_ST33ZP24 and SPI.
1271 CONFIG_TPM_ATMEL_TWI
1272 Support for Atmel TWI TPM device. Requires I2C support.
1275 Support for generic parallel port TPM devices. Only one device
1276 per system is supported at this time.
1278 CONFIG_TPM_TIS_BASE_ADDRESS
1279 Base address where the generic TPM device is mapped
1280 to. Contemporary x86 systems usually map it at
1284 Add tpm monitor functions.
1285 Requires CONFIG_TPM. If CONFIG_TPM_AUTH_SESSIONS is set, also
1286 provides monitor access to authorized functions.
1289 Define this to enable the TPM support library which provides
1290 functional interfaces to some TPM commands.
1291 Requires support for a TPM device.
1293 CONFIG_TPM_AUTH_SESSIONS
1294 Define this to enable authorized functions in the TPM library.
1295 Requires CONFIG_TPM and CONFIG_SHA1.
1298 At the moment only the UHCI host controller is
1299 supported (PIP405, MIP405, MPC5200); define
1300 CONFIG_USB_UHCI to enable it.
1301 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
1302 and define CONFIG_USB_STORAGE to enable the USB
1305 Supported are USB Keyboards and USB Floppy drives
1307 MPC5200 USB requires additional defines:
1309 for 528 MHz Clock: 0x0001bbbb
1313 for differential drivers: 0x00001000
1314 for single ended drivers: 0x00005000
1315 for differential drivers on PSC3: 0x00000100
1316 for single ended drivers on PSC3: 0x00004100
1317 CONFIG_SYS_USB_EVENT_POLL
1318 May be defined to allow interrupt polling
1319 instead of using asynchronous interrupts
1321 CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
1322 txfilltuning field in the EHCI controller on reset.
1324 CONFIG_USB_DWC2_REG_ADDR the physical CPU address of the DWC2
1325 HW module registers.
1328 Define the below if you wish to use the USB console.
1329 Once firmware is rebuilt from a serial console issue the
1330 command "setenv stdin usbtty; setenv stdout usbtty" and
1331 attach your USB cable. The Unix command "dmesg" should print
1332 it has found a new device. The environment variable usbtty
1333 can be set to gserial or cdc_acm to enable your device to
1334 appear to a USB host as a Linux gserial device or a
1335 Common Device Class Abstract Control Model serial device.
1336 If you select usbtty = gserial you should be able to enumerate
1338 # modprobe usbserial vendor=0xVendorID product=0xProductID
1339 else if using cdc_acm, simply setting the environment
1340 variable usbtty to be cdc_acm should suffice. The following
1341 might be defined in YourBoardName.h
1344 Define this to build a UDC device
1347 Define this to have a tty type of device available to
1348 talk to the UDC device
1351 Define this to enable the high speed support for usb
1352 device and usbtty. If this feature is enabled, a routine
1353 int is_usbd_high_speed(void)
1354 also needs to be defined by the driver to dynamically poll
1355 whether the enumeration has succeded at high speed or full
1358 CONFIG_SYS_CONSOLE_IS_IN_ENV
1359 Define this if you want stdin, stdout &/or stderr to
1363 CONFIG_SYS_USB_EXTC_CLK 0xBLAH
1364 Derive USB clock from external clock "blah"
1365 - CONFIG_SYS_USB_EXTC_CLK 0x02
1367 If you have a USB-IF assigned VendorID then you may wish to
1368 define your own vendor specific values either in BoardName.h
1369 or directly in usbd_vendor_info.h. If you don't define
1370 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
1371 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
1372 should pretend to be a Linux device to it's target host.
1374 CONFIG_USBD_MANUFACTURER
1375 Define this string as the name of your company for
1376 - CONFIG_USBD_MANUFACTURER "my company"
1378 CONFIG_USBD_PRODUCT_NAME
1379 Define this string as the name of your product
1380 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
1382 CONFIG_USBD_VENDORID
1383 Define this as your assigned Vendor ID from the USB
1384 Implementors Forum. This *must* be a genuine Vendor ID
1385 to avoid polluting the USB namespace.
1386 - CONFIG_USBD_VENDORID 0xFFFF
1388 CONFIG_USBD_PRODUCTID
1389 Define this as the unique Product ID
1391 - CONFIG_USBD_PRODUCTID 0xFFFF
1393 - ULPI Layer Support:
1394 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
1395 the generic ULPI layer. The generic layer accesses the ULPI PHY
1396 via the platform viewport, so you need both the genric layer and
1397 the viewport enabled. Currently only Chipidea/ARC based
1398 viewport is supported.
1399 To enable the ULPI layer support, define CONFIG_USB_ULPI and
1400 CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
1401 If your ULPI phy needs a different reference clock than the
1402 standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to
1403 the appropriate value in Hz.
1406 The MMC controller on the Intel PXA is supported. To
1407 enable this define CONFIG_MMC. The MMC can be
1408 accessed from the boot prompt by mapping the device
1409 to physical memory similar to flash. Command line is
1410 enabled with CONFIG_CMD_MMC. The MMC driver also works with
1411 the FAT fs. This is enabled with CONFIG_CMD_FAT.
1414 Support for Renesas on-chip MMCIF controller
1416 CONFIG_SH_MMCIF_ADDR
1417 Define the base address of MMCIF registers
1420 Define the clock frequency for MMCIF
1422 CONFIG_SUPPORT_EMMC_BOOT
1423 Enable some additional features of the eMMC boot partitions.
1425 CONFIG_SUPPORT_EMMC_RPMB
1426 Enable the commands for reading, writing and programming the
1427 key for the Replay Protection Memory Block partition in eMMC.
1429 - USB Device Firmware Update (DFU) class support:
1430 CONFIG_USB_FUNCTION_DFU
1431 This enables the USB portion of the DFU USB class
1434 This enables the command "dfu" which is used to have
1435 U-Boot create a DFU class device via USB. This command
1436 requires that the "dfu_alt_info" environment variable be
1437 set and define the alt settings to expose to the host.
1440 This enables support for exposing (e)MMC devices via DFU.
1443 This enables support for exposing NAND devices via DFU.
1446 This enables support for exposing RAM via DFU.
1447 Note: DFU spec refer to non-volatile memory usage, but
1448 allow usages beyond the scope of spec - here RAM usage,
1449 one that would help mostly the developer.
1451 CONFIG_SYS_DFU_DATA_BUF_SIZE
1452 Dfu transfer uses a buffer before writing data to the
1453 raw storage device. Make the size (in bytes) of this buffer
1454 configurable. The size of this buffer is also configurable
1455 through the "dfu_bufsiz" environment variable.
1457 CONFIG_SYS_DFU_MAX_FILE_SIZE
1458 When updating files rather than the raw storage device,
1459 we use a static buffer to copy the file into and then write
1460 the buffer once we've been given the whole file. Define
1461 this to the maximum filesize (in bytes) for the buffer.
1462 Default is 4 MiB if undefined.
1464 DFU_DEFAULT_POLL_TIMEOUT
1465 Poll timeout [ms], is the timeout a device can send to the
1466 host. The host must wait for this timeout before sending
1467 a subsequent DFU_GET_STATUS request to the device.
1469 DFU_MANIFEST_POLL_TIMEOUT
1470 Poll timeout [ms], which the device sends to the host when
1471 entering dfuMANIFEST state. Host waits this timeout, before
1472 sending again an USB request to the device.
1474 - USB Device Android Fastboot support:
1475 CONFIG_USB_FUNCTION_FASTBOOT
1476 This enables the USB part of the fastboot gadget
1479 This enables the command "fastboot" which enables the Android
1480 fastboot mode for the platform's USB device. Fastboot is a USB
1481 protocol for downloading images, flashing and device control
1482 used on Android devices.
1483 See doc/README.android-fastboot for more information.
1485 CONFIG_ANDROID_BOOT_IMAGE
1486 This enables support for booting images which use the Android
1487 image format header.
1489 CONFIG_FASTBOOT_BUF_ADDR
1490 The fastboot protocol requires a large memory buffer for
1491 downloads. Define this to the starting RAM address to use for
1494 CONFIG_FASTBOOT_BUF_SIZE
1495 The fastboot protocol requires a large memory buffer for
1496 downloads. This buffer should be as large as possible for a
1497 platform. Define this to the size available RAM for fastboot.
1499 CONFIG_FASTBOOT_FLASH
1500 The fastboot protocol includes a "flash" command for writing
1501 the downloaded image to a non-volatile storage device. Define
1502 this to enable the "fastboot flash" command.
1504 CONFIG_FASTBOOT_FLASH_MMC_DEV
1505 The fastboot "flash" command requires additional information
1506 regarding the non-volatile storage device. Define this to
1507 the eMMC device that fastboot should use to store the image.
1509 CONFIG_FASTBOOT_GPT_NAME
1510 The fastboot "flash" command supports writing the downloaded
1511 image to the Protective MBR and the Primary GUID Partition
1512 Table. (Additionally, this downloaded image is post-processed
1513 to generate and write the Backup GUID Partition Table.)
1514 This occurs when the specified "partition name" on the
1515 "fastboot flash" command line matches this value.
1516 The default is "gpt" if undefined.
1518 CONFIG_FASTBOOT_MBR_NAME
1519 The fastboot "flash" command supports writing the downloaded
1521 This occurs when the "partition name" specified on the
1522 "fastboot flash" command line matches this value.
1523 If not defined the default value "mbr" is used.
1525 - Journaling Flash filesystem support:
1527 Define these for a default partition on a NAND device
1529 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1530 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1531 Define these for a default partition on a NOR device
1533 - FAT(File Allocation Table) filesystem write function support:
1536 Define this to enable support for saving memory data as a
1537 file in FAT formatted partition.
1539 This will also enable the command "fatwrite" enabling the
1540 user to write files to FAT.
1542 - FAT(File Allocation Table) filesystem cluster size:
1543 CONFIG_FS_FAT_MAX_CLUSTSIZE
1545 Define the max cluster size for fat operations else
1546 a default value of 65536 will be defined.
1549 See Kconfig help for available keyboard drivers.
1553 Define this to enable a custom keyboard support.
1554 This simply calls drv_keyboard_init() which must be
1555 defined in your board-specific files. This option is deprecated
1556 and is only used by novena. For new boards, use driver model
1561 Enable the Freescale DIU video driver. Reference boards for
1562 SOCs that have a DIU should define this macro to enable DIU
1563 support, and should also define these other macros:
1568 CONFIG_VIDEO_SW_CURSOR
1569 CONFIG_VGA_AS_SINGLE_DEVICE
1571 CONFIG_VIDEO_BMP_LOGO
1573 The DIU driver will look for the 'video-mode' environment
1574 variable, and if defined, enable the DIU as a console during
1575 boot. See the documentation file doc/README.video for a
1576 description of this variable.
1578 - LCD Support: CONFIG_LCD
1580 Define this to enable LCD support (for output to LCD
1581 display); also select one of the supported displays
1582 by defining one of these:
1586 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1588 CONFIG_NEC_NL6448AC33:
1590 NEC NL6448AC33-18. Active, color, single scan.
1592 CONFIG_NEC_NL6448BC20
1594 NEC NL6448BC20-08. 6.5", 640x480.
1595 Active, color, single scan.
1597 CONFIG_NEC_NL6448BC33_54
1599 NEC NL6448BC33-54. 10.4", 640x480.
1600 Active, color, single scan.
1604 Sharp 320x240. Active, color, single scan.
1605 It isn't 16x9, and I am not sure what it is.
1607 CONFIG_SHARP_LQ64D341
1609 Sharp LQ64D341 display, 640x480.
1610 Active, color, single scan.
1614 HLD1045 display, 640x480.
1615 Active, color, single scan.
1619 Optrex CBL50840-2 NF-FW 99 22 M5
1621 Hitachi LMG6912RPFC-00T
1625 320x240. Black & white.
1627 CONFIG_LCD_ALIGNMENT
1629 Normally the LCD is page-aligned (typically 4KB). If this is
1630 defined then the LCD will be aligned to this value instead.
1631 For ARM it is sometimes useful to use MMU_SECTION_SIZE
1632 here, since it is cheaper to change data cache settings on
1633 a per-section basis.
1638 Sometimes, for example if the display is mounted in portrait
1639 mode or even if it's mounted landscape but rotated by 180degree,
1640 we need to rotate our content of the display relative to the
1641 framebuffer, so that user can read the messages which are
1643 Once CONFIG_LCD_ROTATION is defined, the lcd_console will be
1644 initialized with a given rotation from "vl_rot" out of
1645 "vidinfo_t" which is provided by the board specific code.
1646 The value for vl_rot is coded as following (matching to
1647 fbcon=rotate:<n> linux-kernel commandline):
1648 0 = no rotation respectively 0 degree
1649 1 = 90 degree rotation
1650 2 = 180 degree rotation
1651 3 = 270 degree rotation
1653 If CONFIG_LCD_ROTATION is not defined, the console will be
1654 initialized with 0degree rotation.
1658 Support drawing of RLE8-compressed bitmaps on the LCD.
1662 Enables an 'i2c edid' command which can read EDID
1663 information over I2C from an attached LCD display.
1665 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1667 If this option is set, the environment is checked for
1668 a variable "splashimage". If found, the usual display
1669 of logo, copyright and system information on the LCD
1670 is suppressed and the BMP image at the address
1671 specified in "splashimage" is loaded instead. The
1672 console is redirected to the "nulldev", too. This
1673 allows for a "silent" boot where a splash screen is
1674 loaded very quickly after power-on.
1676 CONFIG_SPLASHIMAGE_GUARD
1678 If this option is set, then U-Boot will prevent the environment
1679 variable "splashimage" from being set to a problematic address
1680 (see doc/README.displaying-bmps).
1681 This option is useful for targets where, due to alignment
1682 restrictions, an improperly aligned BMP image will cause a data
1683 abort. If you think you will not have problems with unaligned
1684 accesses (for example because your toolchain prevents them)
1685 there is no need to set this option.
1687 CONFIG_SPLASH_SCREEN_ALIGN
1689 If this option is set the splash image can be freely positioned
1690 on the screen. Environment variable "splashpos" specifies the
1691 position as "x,y". If a positive number is given it is used as
1692 number of pixel from left/top. If a negative number is given it
1693 is used as number of pixel from right/bottom. You can also
1694 specify 'm' for centering the image.
1697 setenv splashpos m,m
1698 => image at center of screen
1700 setenv splashpos 30,20
1701 => image at x = 30 and y = 20
1703 setenv splashpos -10,m
1704 => vertically centered image
1705 at x = dspWidth - bmpWidth - 9
1707 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1709 If this option is set, additionally to standard BMP
1710 images, gzipped BMP images can be displayed via the
1711 splashscreen support or the bmp command.
1713 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1715 If this option is set, 8-bit RLE compressed BMP images
1716 can be displayed via the splashscreen support or the
1719 - Compression support:
1722 Enabled by default to support gzip compressed images.
1726 If this option is set, support for bzip2 compressed
1727 images is included. If not, only uncompressed and gzip
1728 compressed images are supported.
1730 NOTE: the bzip2 algorithm requires a lot of RAM, so
1731 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1736 If this option is set, support for lzma compressed
1739 Note: The LZMA algorithm adds between 2 and 4KB of code and it
1740 requires an amount of dynamic memory that is given by the
1743 (1846 + 768 << (lc + lp)) * sizeof(uint16)
1745 Where lc and lp stand for, respectively, Literal context bits
1746 and Literal pos bits.
1748 This value is upper-bounded by 14MB in the worst case. Anyway,
1749 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
1750 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
1751 a very small buffer.
1753 Use the lzmainfo tool to determinate the lc and lp values and
1754 then calculate the amount of needed dynamic memory (ensuring
1755 the appropriate CONFIG_SYS_MALLOC_LEN value).
1759 If this option is set, support for LZO compressed images
1765 The address of PHY on MII bus.
1767 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1769 The clock frequency of the MII bus
1773 If this option is set, support for speed/duplex
1774 detection of gigabit PHY is included.
1776 CONFIG_PHY_RESET_DELAY
1778 Some PHY like Intel LXT971A need extra delay after
1779 reset before any MII register access is possible.
1780 For such PHY, set this option to the usec delay
1781 required. (minimum 300usec for LXT971A)
1783 CONFIG_PHY_CMD_DELAY (ppc4xx)
1785 Some PHY like Intel LXT971A need extra delay after
1786 command issued before MII status register can be read
1791 Define a default value for the IP address to use for
1792 the default Ethernet interface, in case this is not
1793 determined through e.g. bootp.
1794 (Environment variable "ipaddr")
1796 - Server IP address:
1799 Defines a default value for the IP address of a TFTP
1800 server to contact when using the "tftboot" command.
1801 (Environment variable "serverip")
1803 CONFIG_KEEP_SERVERADDR
1805 Keeps the server's MAC address, in the env 'serveraddr'
1806 for passing to bootargs (like Linux's netconsole option)
1808 - Gateway IP address:
1811 Defines a default value for the IP address of the
1812 default router where packets to other networks are
1814 (Environment variable "gatewayip")
1819 Defines a default value for the subnet mask (or
1820 routing prefix) which is used to determine if an IP
1821 address belongs to the local subnet or needs to be
1822 forwarded through a router.
1823 (Environment variable "netmask")
1825 - Multicast TFTP Mode:
1828 Defines whether you want to support multicast TFTP as per
1829 rfc-2090; for example to work with atftp. Lets lots of targets
1830 tftp down the same boot image concurrently. Note: the Ethernet
1831 driver in use must provide a function: mcast() to join/leave a
1834 - BOOTP Recovery Mode:
1835 CONFIG_BOOTP_RANDOM_DELAY
1837 If you have many targets in a network that try to
1838 boot using BOOTP, you may want to avoid that all
1839 systems send out BOOTP requests at precisely the same
1840 moment (which would happen for instance at recovery
1841 from a power failure, when all systems will try to
1842 boot, thus flooding the BOOTP server. Defining
1843 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1844 inserted before sending out BOOTP requests. The
1845 following delays are inserted then:
1847 1st BOOTP request: delay 0 ... 1 sec
1848 2nd BOOTP request: delay 0 ... 2 sec
1849 3rd BOOTP request: delay 0 ... 4 sec
1851 BOOTP requests: delay 0 ... 8 sec
1853 CONFIG_BOOTP_ID_CACHE_SIZE
1855 BOOTP packets are uniquely identified using a 32-bit ID. The
1856 server will copy the ID from client requests to responses and
1857 U-Boot will use this to determine if it is the destination of
1858 an incoming response. Some servers will check that addresses
1859 aren't in use before handing them out (usually using an ARP
1860 ping) and therefore take up to a few hundred milliseconds to
1861 respond. Network congestion may also influence the time it
1862 takes for a response to make it back to the client. If that
1863 time is too long, U-Boot will retransmit requests. In order
1864 to allow earlier responses to still be accepted after these
1865 retransmissions, U-Boot's BOOTP client keeps a small cache of
1866 IDs. The CONFIG_BOOTP_ID_CACHE_SIZE controls the size of this
1867 cache. The default is to keep IDs for up to four outstanding
1868 requests. Increasing this will allow U-Boot to accept offers
1869 from a BOOTP client in networks with unusually high latency.
1871 - DHCP Advanced Options:
1872 You can fine tune the DHCP functionality by defining
1873 CONFIG_BOOTP_* symbols:
1875 CONFIG_BOOTP_SUBNETMASK
1876 CONFIG_BOOTP_GATEWAY
1877 CONFIG_BOOTP_HOSTNAME
1878 CONFIG_BOOTP_NISDOMAIN
1879 CONFIG_BOOTP_BOOTPATH
1880 CONFIG_BOOTP_BOOTFILESIZE
1883 CONFIG_BOOTP_SEND_HOSTNAME
1884 CONFIG_BOOTP_NTPSERVER
1885 CONFIG_BOOTP_TIMEOFFSET
1886 CONFIG_BOOTP_VENDOREX
1887 CONFIG_BOOTP_MAY_FAIL
1889 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1890 environment variable, not the BOOTP server.
1892 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
1893 after the configured retry count, the call will fail
1894 instead of starting over. This can be used to fail over
1895 to Link-local IP address configuration if the DHCP server
1898 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1899 serverip from a DHCP server, it is possible that more
1900 than one DNS serverip is offered to the client.
1901 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1902 serverip will be stored in the additional environment
1903 variable "dnsip2". The first DNS serverip is always
1904 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1907 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1908 to do a dynamic update of a DNS server. To do this, they
1909 need the hostname of the DHCP requester.
1910 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1911 of the "hostname" environment variable is passed as
1912 option 12 to the DHCP server.
1914 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1916 A 32bit value in microseconds for a delay between
1917 receiving a "DHCP Offer" and sending the "DHCP Request".
1918 This fixes a problem with certain DHCP servers that don't
1919 respond 100% of the time to a "DHCP request". E.g. On an
1920 AT91RM9200 processor running at 180MHz, this delay needed
1921 to be *at least* 15,000 usec before a Windows Server 2003
1922 DHCP server would reply 100% of the time. I recommend at
1923 least 50,000 usec to be safe. The alternative is to hope
1924 that one of the retries will be successful but note that
1925 the DHCP timeout and retry process takes a longer than
1928 - Link-local IP address negotiation:
1929 Negotiate with other link-local clients on the local network
1930 for an address that doesn't require explicit configuration.
1931 This is especially useful if a DHCP server cannot be guaranteed
1932 to exist in all environments that the device must operate.
1934 See doc/README.link-local for more information.
1937 CONFIG_CDP_DEVICE_ID
1939 The device id used in CDP trigger frames.
1941 CONFIG_CDP_DEVICE_ID_PREFIX
1943 A two character string which is prefixed to the MAC address
1948 A printf format string which contains the ascii name of
1949 the port. Normally is set to "eth%d" which sets
1950 eth0 for the first Ethernet, eth1 for the second etc.
1952 CONFIG_CDP_CAPABILITIES
1954 A 32bit integer which indicates the device capabilities;
1955 0x00000010 for a normal host which does not forwards.
1959 An ascii string containing the version of the software.
1963 An ascii string containing the name of the platform.
1967 A 32bit integer sent on the trigger.
1969 CONFIG_CDP_POWER_CONSUMPTION
1971 A 16bit integer containing the power consumption of the
1972 device in .1 of milliwatts.
1974 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1976 A byte containing the id of the VLAN.
1978 - Status LED: CONFIG_LED_STATUS
1980 Several configurations allow to display the current
1981 status using a LED. For instance, the LED will blink
1982 fast while running U-Boot code, stop blinking as
1983 soon as a reply to a BOOTP request was received, and
1984 start blinking slow once the Linux kernel is running
1985 (supported by a status LED driver in the Linux
1986 kernel). Defining CONFIG_LED_STATUS enables this
1991 CONFIG_LED_STATUS_GPIO
1992 The status LED can be connected to a GPIO pin.
1993 In such cases, the gpio_led driver can be used as a
1994 status LED backend implementation. Define CONFIG_LED_STATUS_GPIO
1995 to include the gpio_led driver in the U-Boot binary.
1997 CONFIG_GPIO_LED_INVERTED_TABLE
1998 Some GPIO connected LEDs may have inverted polarity in which
1999 case the GPIO high value corresponds to LED off state and
2000 GPIO low value corresponds to LED on state.
2001 In such cases CONFIG_GPIO_LED_INVERTED_TABLE may be defined
2002 with a list of GPIO LEDs that have inverted polarity.
2004 - CAN Support: CONFIG_CAN_DRIVER
2006 Defining CONFIG_CAN_DRIVER enables CAN driver support
2007 on those systems that support this (optional)
2008 feature, like the TQM8xxL modules.
2010 - I2C Support: CONFIG_SYS_I2C
2012 This enable the NEW i2c subsystem, and will allow you to use
2013 i2c commands at the u-boot command line (as long as you set
2014 CONFIG_CMD_I2C in CONFIG_COMMANDS) and communicate with i2c
2015 based realtime clock chips or other i2c devices. See
2016 common/cmd_i2c.c for a description of the command line
2019 ported i2c driver to the new framework:
2020 - drivers/i2c/soft_i2c.c:
2021 - activate first bus with CONFIG_SYS_I2C_SOFT define
2022 CONFIG_SYS_I2C_SOFT_SPEED and CONFIG_SYS_I2C_SOFT_SLAVE
2023 for defining speed and slave address
2024 - activate second bus with I2C_SOFT_DECLARATIONS2 define
2025 CONFIG_SYS_I2C_SOFT_SPEED_2 and CONFIG_SYS_I2C_SOFT_SLAVE_2
2026 for defining speed and slave address
2027 - activate third bus with I2C_SOFT_DECLARATIONS3 define
2028 CONFIG_SYS_I2C_SOFT_SPEED_3 and CONFIG_SYS_I2C_SOFT_SLAVE_3
2029 for defining speed and slave address
2030 - activate fourth bus with I2C_SOFT_DECLARATIONS4 define
2031 CONFIG_SYS_I2C_SOFT_SPEED_4 and CONFIG_SYS_I2C_SOFT_SLAVE_4
2032 for defining speed and slave address
2034 - drivers/i2c/fsl_i2c.c:
2035 - activate i2c driver with CONFIG_SYS_I2C_FSL
2036 define CONFIG_SYS_FSL_I2C_OFFSET for setting the register
2037 offset CONFIG_SYS_FSL_I2C_SPEED for the i2c speed and
2038 CONFIG_SYS_FSL_I2C_SLAVE for the slave addr of the first
2040 - If your board supports a second fsl i2c bus, define
2041 CONFIG_SYS_FSL_I2C2_OFFSET for the register offset
2042 CONFIG_SYS_FSL_I2C2_SPEED for the speed and
2043 CONFIG_SYS_FSL_I2C2_SLAVE for the slave address of the
2046 - drivers/i2c/tegra_i2c.c:
2047 - activate this driver with CONFIG_SYS_I2C_TEGRA
2048 - This driver adds 4 i2c buses with a fix speed from
2049 100000 and the slave addr 0!
2051 - drivers/i2c/ppc4xx_i2c.c
2052 - activate this driver with CONFIG_SYS_I2C_PPC4XX
2053 - CONFIG_SYS_I2C_PPC4XX_CH0 activate hardware channel 0
2054 - CONFIG_SYS_I2C_PPC4XX_CH1 activate hardware channel 1
2056 - drivers/i2c/i2c_mxc.c
2057 - activate this driver with CONFIG_SYS_I2C_MXC
2058 - enable bus 1 with CONFIG_SYS_I2C_MXC_I2C1
2059 - enable bus 2 with CONFIG_SYS_I2C_MXC_I2C2
2060 - enable bus 3 with CONFIG_SYS_I2C_MXC_I2C3
2061 - enable bus 4 with CONFIG_SYS_I2C_MXC_I2C4
2062 - define speed for bus 1 with CONFIG_SYS_MXC_I2C1_SPEED
2063 - define slave for bus 1 with CONFIG_SYS_MXC_I2C1_SLAVE
2064 - define speed for bus 2 with CONFIG_SYS_MXC_I2C2_SPEED
2065 - define slave for bus 2 with CONFIG_SYS_MXC_I2C2_SLAVE
2066 - define speed for bus 3 with CONFIG_SYS_MXC_I2C3_SPEED
2067 - define slave for bus 3 with CONFIG_SYS_MXC_I2C3_SLAVE
2068 - define speed for bus 4 with CONFIG_SYS_MXC_I2C4_SPEED
2069 - define slave for bus 4 with CONFIG_SYS_MXC_I2C4_SLAVE
2070 If those defines are not set, default value is 100000
2071 for speed, and 0 for slave.
2073 - drivers/i2c/rcar_i2c.c:
2074 - activate this driver with CONFIG_SYS_I2C_RCAR
2075 - This driver adds 4 i2c buses
2077 - CONFIG_SYS_RCAR_I2C0_BASE for setting the register channel 0
2078 - CONFIG_SYS_RCAR_I2C0_SPEED for for the speed channel 0
2079 - CONFIG_SYS_RCAR_I2C1_BASE for setting the register channel 1
2080 - CONFIG_SYS_RCAR_I2C1_SPEED for for the speed channel 1
2081 - CONFIG_SYS_RCAR_I2C2_BASE for setting the register channel 2
2082 - CONFIG_SYS_RCAR_I2C2_SPEED for for the speed channel 2
2083 - CONFIG_SYS_RCAR_I2C3_BASE for setting the register channel 3
2084 - CONFIG_SYS_RCAR_I2C3_SPEED for for the speed channel 3
2085 - CONFIF_SYS_RCAR_I2C_NUM_CONTROLLERS for number of i2c buses
2087 - drivers/i2c/sh_i2c.c:
2088 - activate this driver with CONFIG_SYS_I2C_SH
2089 - This driver adds from 2 to 5 i2c buses
2091 - CONFIG_SYS_I2C_SH_BASE0 for setting the register channel 0
2092 - CONFIG_SYS_I2C_SH_SPEED0 for for the speed channel 0
2093 - CONFIG_SYS_I2C_SH_BASE1 for setting the register channel 1
2094 - CONFIG_SYS_I2C_SH_SPEED1 for for the speed channel 1
2095 - CONFIG_SYS_I2C_SH_BASE2 for setting the register channel 2
2096 - CONFIG_SYS_I2C_SH_SPEED2 for for the speed channel 2
2097 - CONFIG_SYS_I2C_SH_BASE3 for setting the register channel 3
2098 - CONFIG_SYS_I2C_SH_SPEED3 for for the speed channel 3
2099 - CONFIG_SYS_I2C_SH_BASE4 for setting the register channel 4
2100 - CONFIG_SYS_I2C_SH_SPEED4 for for the speed channel 4
2101 - CONFIG_SYS_I2C_SH_NUM_CONTROLLERS for number of i2c buses
2103 - drivers/i2c/omap24xx_i2c.c
2104 - activate this driver with CONFIG_SYS_I2C_OMAP24XX
2105 - CONFIG_SYS_OMAP24_I2C_SPEED speed channel 0
2106 - CONFIG_SYS_OMAP24_I2C_SLAVE slave addr channel 0
2107 - CONFIG_SYS_OMAP24_I2C_SPEED1 speed channel 1
2108 - CONFIG_SYS_OMAP24_I2C_SLAVE1 slave addr channel 1
2109 - CONFIG_SYS_OMAP24_I2C_SPEED2 speed channel 2
2110 - CONFIG_SYS_OMAP24_I2C_SLAVE2 slave addr channel 2
2111 - CONFIG_SYS_OMAP24_I2C_SPEED3 speed channel 3
2112 - CONFIG_SYS_OMAP24_I2C_SLAVE3 slave addr channel 3
2113 - CONFIG_SYS_OMAP24_I2C_SPEED4 speed channel 4
2114 - CONFIG_SYS_OMAP24_I2C_SLAVE4 slave addr channel 4
2116 - drivers/i2c/zynq_i2c.c
2117 - activate this driver with CONFIG_SYS_I2C_ZYNQ
2118 - set CONFIG_SYS_I2C_ZYNQ_SPEED for speed setting
2119 - set CONFIG_SYS_I2C_ZYNQ_SLAVE for slave addr
2121 - drivers/i2c/s3c24x0_i2c.c:
2122 - activate this driver with CONFIG_SYS_I2C_S3C24X0
2123 - This driver adds i2c buses (11 for Exynos5250, Exynos5420
2124 9 i2c buses for Exynos4 and 1 for S3C24X0 SoCs from Samsung)
2125 with a fix speed from 100000 and the slave addr 0!
2127 - drivers/i2c/ihs_i2c.c
2128 - activate this driver with CONFIG_SYS_I2C_IHS
2129 - CONFIG_SYS_I2C_IHS_CH0 activate hardware channel 0
2130 - CONFIG_SYS_I2C_IHS_SPEED_0 speed channel 0
2131 - CONFIG_SYS_I2C_IHS_SLAVE_0 slave addr channel 0
2132 - CONFIG_SYS_I2C_IHS_CH1 activate hardware channel 1
2133 - CONFIG_SYS_I2C_IHS_SPEED_1 speed channel 1
2134 - CONFIG_SYS_I2C_IHS_SLAVE_1 slave addr channel 1
2135 - CONFIG_SYS_I2C_IHS_CH2 activate hardware channel 2
2136 - CONFIG_SYS_I2C_IHS_SPEED_2 speed channel 2
2137 - CONFIG_SYS_I2C_IHS_SLAVE_2 slave addr channel 2
2138 - CONFIG_SYS_I2C_IHS_CH3 activate hardware channel 3
2139 - CONFIG_SYS_I2C_IHS_SPEED_3 speed channel 3
2140 - CONFIG_SYS_I2C_IHS_SLAVE_3 slave addr channel 3
2141 - activate dual channel with CONFIG_SYS_I2C_IHS_DUAL
2142 - CONFIG_SYS_I2C_IHS_SPEED_0_1 speed channel 0_1
2143 - CONFIG_SYS_I2C_IHS_SLAVE_0_1 slave addr channel 0_1
2144 - CONFIG_SYS_I2C_IHS_SPEED_1_1 speed channel 1_1
2145 - CONFIG_SYS_I2C_IHS_SLAVE_1_1 slave addr channel 1_1
2146 - CONFIG_SYS_I2C_IHS_SPEED_2_1 speed channel 2_1
2147 - CONFIG_SYS_I2C_IHS_SLAVE_2_1 slave addr channel 2_1
2148 - CONFIG_SYS_I2C_IHS_SPEED_3_1 speed channel 3_1
2149 - CONFIG_SYS_I2C_IHS_SLAVE_3_1 slave addr channel 3_1
2153 CONFIG_SYS_NUM_I2C_BUSES
2154 Hold the number of i2c buses you want to use.
2156 CONFIG_SYS_I2C_DIRECT_BUS
2157 define this, if you don't use i2c muxes on your hardware.
2158 if CONFIG_SYS_I2C_MAX_HOPS is not defined or == 0 you can
2161 CONFIG_SYS_I2C_MAX_HOPS
2162 define how many muxes are maximal consecutively connected
2163 on one i2c bus. If you not use i2c muxes, omit this
2166 CONFIG_SYS_I2C_BUSES
2167 hold a list of buses you want to use, only used if
2168 CONFIG_SYS_I2C_DIRECT_BUS is not defined, for example
2169 a board with CONFIG_SYS_I2C_MAX_HOPS = 1 and
2170 CONFIG_SYS_NUM_I2C_BUSES = 9:
2172 CONFIG_SYS_I2C_BUSES {{0, {I2C_NULL_HOP}}, \
2173 {0, {{I2C_MUX_PCA9547, 0x70, 1}}}, \
2174 {0, {{I2C_MUX_PCA9547, 0x70, 2}}}, \
2175 {0, {{I2C_MUX_PCA9547, 0x70, 3}}}, \
2176 {0, {{I2C_MUX_PCA9547, 0x70, 4}}}, \
2177 {0, {{I2C_MUX_PCA9547, 0x70, 5}}}, \
2178 {1, {I2C_NULL_HOP}}, \
2179 {1, {{I2C_MUX_PCA9544, 0x72, 1}}}, \
2180 {1, {{I2C_MUX_PCA9544, 0x72, 2}}}, \
2184 bus 0 on adapter 0 without a mux
2185 bus 1 on adapter 0 with a PCA9547 on address 0x70 port 1
2186 bus 2 on adapter 0 with a PCA9547 on address 0x70 port 2
2187 bus 3 on adapter 0 with a PCA9547 on address 0x70 port 3
2188 bus 4 on adapter 0 with a PCA9547 on address 0x70 port 4
2189 bus 5 on adapter 0 with a PCA9547 on address 0x70 port 5
2190 bus 6 on adapter 1 without a mux
2191 bus 7 on adapter 1 with a PCA9544 on address 0x72 port 1
2192 bus 8 on adapter 1 with a PCA9544 on address 0x72 port 2
2194 If you do not have i2c muxes on your board, omit this define.
2196 - Legacy I2C Support:
2197 If you use the software i2c interface (CONFIG_SYS_I2C_SOFT)
2198 then the following macros need to be defined (examples are
2199 from include/configs/lwmon.h):
2203 (Optional). Any commands necessary to enable the I2C
2204 controller or configure ports.
2206 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
2210 (Only for MPC8260 CPU). The I/O port to use (the code
2211 assumes both bits are on the same port). Valid values
2212 are 0..3 for ports A..D.
2216 The code necessary to make the I2C data line active
2217 (driven). If the data line is open collector, this
2220 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
2224 The code necessary to make the I2C data line tri-stated
2225 (inactive). If the data line is open collector, this
2228 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
2232 Code that returns true if the I2C data line is high,
2235 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
2239 If <bit> is true, sets the I2C data line high. If it
2240 is false, it clears it (low).
2242 eg: #define I2C_SDA(bit) \
2243 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
2244 else immr->im_cpm.cp_pbdat &= ~PB_SDA
2248 If <bit> is true, sets the I2C clock line high. If it
2249 is false, it clears it (low).
2251 eg: #define I2C_SCL(bit) \
2252 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
2253 else immr->im_cpm.cp_pbdat &= ~PB_SCL
2257 This delay is invoked four times per clock cycle so this
2258 controls the rate of data transfer. The data rate thus
2259 is 1 / (I2C_DELAY * 4). Often defined to be something
2262 #define I2C_DELAY udelay(2)
2264 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
2266 If your arch supports the generic GPIO framework (asm/gpio.h),
2267 then you may alternatively define the two GPIOs that are to be
2268 used as SCL / SDA. Any of the previous I2C_xxx macros will
2269 have GPIO-based defaults assigned to them as appropriate.
2271 You should define these to the GPIO value as given directly to
2272 the generic GPIO functions.
2274 CONFIG_SYS_I2C_INIT_BOARD
2276 When a board is reset during an i2c bus transfer
2277 chips might think that the current transfer is still
2278 in progress. On some boards it is possible to access
2279 the i2c SCLK line directly, either by using the
2280 processor pin as a GPIO or by having a second pin
2281 connected to the bus. If this option is defined a
2282 custom i2c_init_board() routine in boards/xxx/board.c
2283 is run early in the boot sequence.
2285 CONFIG_I2C_MULTI_BUS
2287 This option allows the use of multiple I2C buses, each of which
2288 must have a controller. At any point in time, only one bus is
2289 active. To switch to a different bus, use the 'i2c dev' command.
2290 Note that bus numbering is zero-based.
2292 CONFIG_SYS_I2C_NOPROBES
2294 This option specifies a list of I2C devices that will be skipped
2295 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
2296 is set, specify a list of bus-device pairs. Otherwise, specify
2297 a 1D array of device addresses
2300 #undef CONFIG_I2C_MULTI_BUS
2301 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
2303 will skip addresses 0x50 and 0x68 on a board with one I2C bus
2305 #define CONFIG_I2C_MULTI_BUS
2306 #define CONFIG_SYS_I2C_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
2308 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
2310 CONFIG_SYS_SPD_BUS_NUM
2312 If defined, then this indicates the I2C bus number for DDR SPD.
2313 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
2315 CONFIG_SYS_RTC_BUS_NUM
2317 If defined, then this indicates the I2C bus number for the RTC.
2318 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
2320 CONFIG_SOFT_I2C_READ_REPEATED_START
2322 defining this will force the i2c_read() function in
2323 the soft_i2c driver to perform an I2C repeated start
2324 between writing the address pointer and reading the
2325 data. If this define is omitted the default behaviour
2326 of doing a stop-start sequence will be used. Most I2C
2327 devices can use either method, but some require one or
2330 - SPI Support: CONFIG_SPI
2332 Enables SPI driver (so far only tested with
2333 SPI EEPROM, also an instance works with Crystal A/D and
2334 D/As on the SACSng board)
2338 Enables the driver for SPI controller on SuperH. Currently
2339 only SH7757 is supported.
2343 Enables a software (bit-bang) SPI driver rather than
2344 using hardware support. This is a general purpose
2345 driver that only requires three general I/O port pins
2346 (two outputs, one input) to function. If this is
2347 defined, the board configuration must define several
2348 SPI configuration items (port pins to use, etc). For
2349 an example, see include/configs/sacsng.h.
2353 Enables a hardware SPI driver for general-purpose reads
2354 and writes. As with CONFIG_SOFT_SPI, the board configuration
2355 must define a list of chip-select function pointers.
2356 Currently supported on some MPC8xxx processors. For an
2357 example, see include/configs/mpc8349emds.h.
2361 Enables the driver for the SPI controllers on i.MX and MXC
2362 SoCs. Currently i.MX31/35/51 are supported.
2364 CONFIG_SYS_SPI_MXC_WAIT
2365 Timeout for waiting until spi transfer completed.
2366 default: (CONFIG_SYS_HZ/100) /* 10 ms */
2368 - FPGA Support: CONFIG_FPGA
2370 Enables FPGA subsystem.
2372 CONFIG_FPGA_<vendor>
2374 Enables support for specific chip vendors.
2377 CONFIG_FPGA_<family>
2379 Enables support for FPGA family.
2380 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
2384 Specify the number of FPGA devices to support.
2386 CONFIG_SYS_FPGA_PROG_FEEDBACK
2388 Enable printing of hash marks during FPGA configuration.
2390 CONFIG_SYS_FPGA_CHECK_BUSY
2392 Enable checks on FPGA configuration interface busy
2393 status by the configuration function. This option
2394 will require a board or device specific function to
2399 If defined, a function that provides delays in the FPGA
2400 configuration driver.
2402 CONFIG_SYS_FPGA_CHECK_CTRLC
2403 Allow Control-C to interrupt FPGA configuration
2405 CONFIG_SYS_FPGA_CHECK_ERROR
2407 Check for configuration errors during FPGA bitfile
2408 loading. For example, abort during Virtex II
2409 configuration if the INIT_B line goes low (which
2410 indicated a CRC error).
2412 CONFIG_SYS_FPGA_WAIT_INIT
2414 Maximum time to wait for the INIT_B line to de-assert
2415 after PROB_B has been de-asserted during a Virtex II
2416 FPGA configuration sequence. The default time is 500
2419 CONFIG_SYS_FPGA_WAIT_BUSY
2421 Maximum time to wait for BUSY to de-assert during
2422 Virtex II FPGA configuration. The default is 5 ms.
2424 CONFIG_SYS_FPGA_WAIT_CONFIG
2426 Time to wait after FPGA configuration. The default is
2429 - Configuration Management:
2432 Some SoCs need special image types (e.g. U-Boot binary
2433 with a special header) as build targets. By defining
2434 CONFIG_BUILD_TARGET in the SoC / board header, this
2435 special image will be automatically built upon calling
2440 If defined, this string will be added to the U-Boot
2441 version information (U_BOOT_VERSION)
2443 - Vendor Parameter Protection:
2445 U-Boot considers the values of the environment
2446 variables "serial#" (Board Serial Number) and
2447 "ethaddr" (Ethernet Address) to be parameters that
2448 are set once by the board vendor / manufacturer, and
2449 protects these variables from casual modification by
2450 the user. Once set, these variables are read-only,
2451 and write or delete attempts are rejected. You can
2452 change this behaviour:
2454 If CONFIG_ENV_OVERWRITE is #defined in your config
2455 file, the write protection for vendor parameters is
2456 completely disabled. Anybody can change or delete
2459 Alternatively, if you define _both_ an ethaddr in the
2460 default env _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2461 Ethernet address is installed in the environment,
2462 which can be changed exactly ONCE by the user. [The
2463 serial# is unaffected by this, i. e. it remains
2466 The same can be accomplished in a more flexible way
2467 for any variable by configuring the type of access
2468 to allow for those variables in the ".flags" variable
2469 or define CONFIG_ENV_FLAGS_LIST_STATIC.
2474 Define this variable to enable the reservation of
2475 "protected RAM", i. e. RAM which is not overwritten
2476 by U-Boot. Define CONFIG_PRAM to hold the number of
2477 kB you want to reserve for pRAM. You can overwrite
2478 this default value by defining an environment
2479 variable "pram" to the number of kB you want to
2480 reserve. Note that the board info structure will
2481 still show the full amount of RAM. If pRAM is
2482 reserved, a new environment variable "mem" will
2483 automatically be defined to hold the amount of
2484 remaining RAM in a form that can be passed as boot
2485 argument to Linux, for instance like that:
2487 setenv bootargs ... mem=\${mem}
2490 This way you can tell Linux not to use this memory,
2491 either, which results in a memory region that will
2492 not be affected by reboots.
2494 *WARNING* If your board configuration uses automatic
2495 detection of the RAM size, you must make sure that
2496 this memory test is non-destructive. So far, the
2497 following board configurations are known to be
2500 IVMS8, IVML24, SPD8xx, TQM8xxL,
2501 HERMES, IP860, RPXlite, LWMON,
2504 - Access to physical memory region (> 4GB)
2505 Some basic support is provided for operations on memory not
2506 normally accessible to U-Boot - e.g. some architectures
2507 support access to more than 4GB of memory on 32-bit
2508 machines using physical address extension or similar.
2509 Define CONFIG_PHYSMEM to access this basic support, which
2510 currently only supports clearing the memory.
2515 Define this variable to stop the system in case of a
2516 fatal error, so that you have to reset it manually.
2517 This is probably NOT a good idea for an embedded
2518 system where you want the system to reboot
2519 automatically as fast as possible, but it may be
2520 useful during development since you can try to debug
2521 the conditions that lead to the situation.
2523 CONFIG_NET_RETRY_COUNT
2525 This variable defines the number of retries for
2526 network operations like ARP, RARP, TFTP, or BOOTP
2527 before giving up the operation. If not defined, a
2528 default value of 5 is used.
2532 Timeout waiting for an ARP reply in milliseconds.
2536 Timeout in milliseconds used in NFS protocol.
2537 If you encounter "ERROR: Cannot umount" in nfs command,
2538 try longer timeout such as
2539 #define CONFIG_NFS_TIMEOUT 10000UL
2541 - Command Interpreter:
2542 CONFIG_AUTO_COMPLETE
2544 Enable auto completion of commands using TAB.
2546 CONFIG_SYS_PROMPT_HUSH_PS2
2548 This defines the secondary prompt string, which is
2549 printed when the command interpreter needs more input
2550 to complete a command. Usually "> ".
2554 In the current implementation, the local variables
2555 space and global environment variables space are
2556 separated. Local variables are those you define by
2557 simply typing `name=value'. To access a local
2558 variable later on, you have write `$name' or
2559 `${name}'; to execute the contents of a variable
2560 directly type `$name' at the command prompt.
2562 Global environment variables are those you use
2563 setenv/printenv to work with. To run a command stored
2564 in such a variable, you need to use the run command,
2565 and you must not use the '$' sign to access them.
2567 To store commands and special characters in a
2568 variable, please use double quotation marks
2569 surrounding the whole text of the variable, instead
2570 of the backslashes before semicolons and special
2573 - Command Line Editing and History:
2574 CONFIG_CMDLINE_EDITING
2576 Enable editing and History functions for interactive
2577 command line input operations
2579 - Command Line PS1/PS2 support:
2580 CONFIG_CMDLINE_PS_SUPPORT
2582 Enable support for changing the command prompt string
2583 at run-time. Only static string is supported so far.
2584 The string is obtained from environment variables PS1
2587 - Default Environment:
2588 CONFIG_EXTRA_ENV_SETTINGS
2590 Define this to contain any number of null terminated
2591 strings (variable = value pairs) that will be part of
2592 the default environment compiled into the boot image.
2594 For example, place something like this in your
2595 board's config file:
2597 #define CONFIG_EXTRA_ENV_SETTINGS \
2601 Warning: This method is based on knowledge about the
2602 internal format how the environment is stored by the
2603 U-Boot code. This is NOT an official, exported
2604 interface! Although it is unlikely that this format
2605 will change soon, there is no guarantee either.
2606 You better know what you are doing here.
2608 Note: overly (ab)use of the default environment is
2609 discouraged. Make sure to check other ways to preset
2610 the environment like the "source" command or the
2613 CONFIG_ENV_VARS_UBOOT_CONFIG
2615 Define this in order to add variables describing the
2616 U-Boot build configuration to the default environment.
2617 These will be named arch, cpu, board, vendor, and soc.
2619 Enabling this option will cause the following to be defined:
2627 CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG
2629 Define this in order to add variables describing certain
2630 run-time determined information about the hardware to the
2631 environment. These will be named board_name, board_rev.
2633 CONFIG_DELAY_ENVIRONMENT
2635 Normally the environment is loaded when the board is
2636 initialised so that it is available to U-Boot. This inhibits
2637 that so that the environment is not available until
2638 explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL
2639 this is instead controlled by the value of
2640 /config/load-environment.
2642 - DataFlash Support:
2643 CONFIG_HAS_DATAFLASH
2645 Defining this option enables DataFlash features and
2646 allows to read/write in Dataflash via the standard
2649 - Serial Flash support
2652 Defining this option enables SPI flash commands
2653 'sf probe/read/write/erase/update'.
2655 Usage requires an initial 'probe' to define the serial
2656 flash parameters, followed by read/write/erase/update
2659 The following defaults may be provided by the platform
2660 to handle the common case when only a single serial
2661 flash is present on the system.
2663 CONFIG_SF_DEFAULT_BUS Bus identifier
2664 CONFIG_SF_DEFAULT_CS Chip-select
2665 CONFIG_SF_DEFAULT_MODE (see include/spi.h)
2666 CONFIG_SF_DEFAULT_SPEED in Hz
2670 Define this option to include a destructive SPI flash
2673 CONFIG_SF_DUAL_FLASH Dual flash memories
2675 Define this option to use dual flash support where two flash
2676 memories can be connected with a given cs line.
2677 Currently Xilinx Zynq qspi supports these type of connections.
2679 - SystemACE Support:
2682 Adding this option adds support for Xilinx SystemACE
2683 chips attached via some sort of local bus. The address
2684 of the chip must also be defined in the
2685 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
2687 #define CONFIG_SYSTEMACE
2688 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
2690 When SystemACE support is added, the "ace" device type
2691 becomes available to the fat commands, i.e. fatls.
2693 - TFTP Fixed UDP Port:
2696 If this is defined, the environment variable tftpsrcp
2697 is used to supply the TFTP UDP source port value.
2698 If tftpsrcp isn't defined, the normal pseudo-random port
2699 number generator is used.
2701 Also, the environment variable tftpdstp is used to supply
2702 the TFTP UDP destination port value. If tftpdstp isn't
2703 defined, the normal port 69 is used.
2705 The purpose for tftpsrcp is to allow a TFTP server to
2706 blindly start the TFTP transfer using the pre-configured
2707 target IP address and UDP port. This has the effect of
2708 "punching through" the (Windows XP) firewall, allowing
2709 the remainder of the TFTP transfer to proceed normally.
2710 A better solution is to properly configure the firewall,
2711 but sometimes that is not allowed.
2716 This enables a generic 'hash' command which can produce
2717 hashes / digests from a few algorithms (e.g. SHA1, SHA256).
2721 Enable the hash verify command (hash -v). This adds to code
2724 Note: There is also a sha1sum command, which should perhaps
2725 be deprecated in favour of 'hash sha1'.
2727 - Freescale i.MX specific commands:
2728 CONFIG_CMD_HDMIDETECT
2729 This enables 'hdmidet' command which returns true if an
2730 HDMI monitor is detected. This command is i.MX 6 specific.
2732 - bootcount support:
2733 CONFIG_BOOTCOUNT_LIMIT
2735 This enables the bootcounter support, see:
2736 http://www.denx.de/wiki/DULG/UBootBootCountLimit
2739 enable special bootcounter support on at91sam9xe based boards.
2741 enable special bootcounter support on da850 based boards.
2742 CONFIG_BOOTCOUNT_RAM
2743 enable support for the bootcounter in RAM
2744 CONFIG_BOOTCOUNT_I2C
2745 enable support for the bootcounter on an i2c (like RTC) device.
2746 CONFIG_SYS_I2C_RTC_ADDR = i2c chip address
2747 CONFIG_SYS_BOOTCOUNT_ADDR = i2c addr which is used for
2749 CONFIG_BOOTCOUNT_ALEN = address len
2751 - Show boot progress:
2752 CONFIG_SHOW_BOOT_PROGRESS
2754 Defining this option allows to add some board-
2755 specific code (calling a user-provided function
2756 "show_boot_progress(int)") that enables you to show
2757 the system's boot progress on some display (for
2758 example, some LED's) on your board. At the moment,
2759 the following checkpoints are implemented:
2762 Legacy uImage format:
2765 1 common/cmd_bootm.c before attempting to boot an image
2766 -1 common/cmd_bootm.c Image header has bad magic number
2767 2 common/cmd_bootm.c Image header has correct magic number
2768 -2 common/cmd_bootm.c Image header has bad checksum
2769 3 common/cmd_bootm.c Image header has correct checksum
2770 -3 common/cmd_bootm.c Image data has bad checksum
2771 4 common/cmd_bootm.c Image data has correct checksum
2772 -4 common/cmd_bootm.c Image is for unsupported architecture
2773 5 common/cmd_bootm.c Architecture check OK
2774 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
2775 6 common/cmd_bootm.c Image Type check OK
2776 -6 common/cmd_bootm.c gunzip uncompression error
2777 -7 common/cmd_bootm.c Unimplemented compression type
2778 7 common/cmd_bootm.c Uncompression OK
2779 8 common/cmd_bootm.c No uncompress/copy overwrite error
2780 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
2782 9 common/image.c Start initial ramdisk verification
2783 -10 common/image.c Ramdisk header has bad magic number
2784 -11 common/image.c Ramdisk header has bad checksum
2785 10 common/image.c Ramdisk header is OK
2786 -12 common/image.c Ramdisk data has bad checksum
2787 11 common/image.c Ramdisk data has correct checksum
2788 12 common/image.c Ramdisk verification complete, start loading
2789 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
2790 13 common/image.c Start multifile image verification
2791 14 common/image.c No initial ramdisk, no multifile, continue.
2793 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
2795 -30 arch/powerpc/lib/board.c Fatal error, hang the system
2796 -31 post/post.c POST test failed, detected by post_output_backlog()
2797 -32 post/post.c POST test failed, detected by post_run_single()
2799 34 common/cmd_doc.c before loading a Image from a DOC device
2800 -35 common/cmd_doc.c Bad usage of "doc" command
2801 35 common/cmd_doc.c correct usage of "doc" command
2802 -36 common/cmd_doc.c No boot device
2803 36 common/cmd_doc.c correct boot device
2804 -37 common/cmd_doc.c Unknown Chip ID on boot device
2805 37 common/cmd_doc.c correct chip ID found, device available
2806 -38 common/cmd_doc.c Read Error on boot device
2807 38 common/cmd_doc.c reading Image header from DOC device OK
2808 -39 common/cmd_doc.c Image header has bad magic number
2809 39 common/cmd_doc.c Image header has correct magic number
2810 -40 common/cmd_doc.c Error reading Image from DOC device
2811 40 common/cmd_doc.c Image header has correct magic number
2812 41 common/cmd_ide.c before loading a Image from a IDE device
2813 -42 common/cmd_ide.c Bad usage of "ide" command
2814 42 common/cmd_ide.c correct usage of "ide" command
2815 -43 common/cmd_ide.c No boot device
2816 43 common/cmd_ide.c boot device found
2817 -44 common/cmd_ide.c Device not available
2818 44 common/cmd_ide.c Device available
2819 -45 common/cmd_ide.c wrong partition selected
2820 45 common/cmd_ide.c partition selected
2821 -46 common/cmd_ide.c Unknown partition table
2822 46 common/cmd_ide.c valid partition table found
2823 -47 common/cmd_ide.c Invalid partition type
2824 47 common/cmd_ide.c correct partition type
2825 -48 common/cmd_ide.c Error reading Image Header on boot device
2826 48 common/cmd_ide.c reading Image Header from IDE device OK
2827 -49 common/cmd_ide.c Image header has bad magic number
2828 49 common/cmd_ide.c Image header has correct magic number
2829 -50 common/cmd_ide.c Image header has bad checksum
2830 50 common/cmd_ide.c Image header has correct checksum
2831 -51 common/cmd_ide.c Error reading Image from IDE device
2832 51 common/cmd_ide.c reading Image from IDE device OK
2833 52 common/cmd_nand.c before loading a Image from a NAND device
2834 -53 common/cmd_nand.c Bad usage of "nand" command
2835 53 common/cmd_nand.c correct usage of "nand" command
2836 -54 common/cmd_nand.c No boot device
2837 54 common/cmd_nand.c boot device found
2838 -55 common/cmd_nand.c Unknown Chip ID on boot device
2839 55 common/cmd_nand.c correct chip ID found, device available
2840 -56 common/cmd_nand.c Error reading Image Header on boot device
2841 56 common/cmd_nand.c reading Image Header from NAND device OK
2842 -57 common/cmd_nand.c Image header has bad magic number
2843 57 common/cmd_nand.c Image header has correct magic number
2844 -58 common/cmd_nand.c Error reading Image from NAND device
2845 58 common/cmd_nand.c reading Image from NAND device OK
2847 -60 common/env_common.c Environment has a bad CRC, using default
2849 64 net/eth.c starting with Ethernet configuration.
2850 -64 net/eth.c no Ethernet found.
2851 65 net/eth.c Ethernet found.
2853 -80 common/cmd_net.c usage wrong
2854 80 common/cmd_net.c before calling net_loop()
2855 -81 common/cmd_net.c some error in net_loop() occurred
2856 81 common/cmd_net.c net_loop() back without error
2857 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
2858 82 common/cmd_net.c trying automatic boot
2859 83 common/cmd_net.c running "source" command
2860 -83 common/cmd_net.c some error in automatic boot or "source" command
2861 84 common/cmd_net.c end without errors
2866 100 common/cmd_bootm.c Kernel FIT Image has correct format
2867 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
2868 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
2869 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
2870 102 common/cmd_bootm.c Kernel unit name specified
2871 -103 common/cmd_bootm.c Can't get kernel subimage node offset
2872 103 common/cmd_bootm.c Found configuration node
2873 104 common/cmd_bootm.c Got kernel subimage node offset
2874 -104 common/cmd_bootm.c Kernel subimage hash verification failed
2875 105 common/cmd_bootm.c Kernel subimage hash verification OK
2876 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
2877 106 common/cmd_bootm.c Architecture check OK
2878 -106 common/cmd_bootm.c Kernel subimage has wrong type
2879 107 common/cmd_bootm.c Kernel subimage type OK
2880 -107 common/cmd_bootm.c Can't get kernel subimage data/size
2881 108 common/cmd_bootm.c Got kernel subimage data/size
2882 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
2883 -109 common/cmd_bootm.c Can't get kernel subimage type
2884 -110 common/cmd_bootm.c Can't get kernel subimage comp
2885 -111 common/cmd_bootm.c Can't get kernel subimage os
2886 -112 common/cmd_bootm.c Can't get kernel subimage load address
2887 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
2889 120 common/image.c Start initial ramdisk verification
2890 -120 common/image.c Ramdisk FIT image has incorrect format
2891 121 common/image.c Ramdisk FIT image has correct format
2892 122 common/image.c No ramdisk subimage unit name, using configuration
2893 -122 common/image.c Can't get configuration for ramdisk subimage
2894 123 common/image.c Ramdisk unit name specified
2895 -124 common/image.c Can't get ramdisk subimage node offset
2896 125 common/image.c Got ramdisk subimage node offset
2897 -125 common/image.c Ramdisk subimage hash verification failed
2898 126 common/image.c Ramdisk subimage hash verification OK
2899 -126 common/image.c Ramdisk subimage for unsupported architecture
2900 127 common/image.c Architecture check OK
2901 -127 common/image.c Can't get ramdisk subimage data/size
2902 128 common/image.c Got ramdisk subimage data/size
2903 129 common/image.c Can't get ramdisk load address
2904 -129 common/image.c Got ramdisk load address
2906 -130 common/cmd_doc.c Incorrect FIT image format
2907 131 common/cmd_doc.c FIT image format OK
2909 -140 common/cmd_ide.c Incorrect FIT image format
2910 141 common/cmd_ide.c FIT image format OK
2912 -150 common/cmd_nand.c Incorrect FIT image format
2913 151 common/cmd_nand.c FIT image format OK
2915 - legacy image format:
2916 CONFIG_IMAGE_FORMAT_LEGACY
2917 enables the legacy image format support in U-Boot.
2920 enabled if CONFIG_FIT_SIGNATURE is not defined.
2922 CONFIG_DISABLE_IMAGE_LEGACY
2923 disable the legacy image format
2925 This define is introduced, as the legacy image format is
2926 enabled per default for backward compatibility.
2928 - Standalone program support:
2929 CONFIG_STANDALONE_LOAD_ADDR
2931 This option defines a board specific value for the
2932 address where standalone program gets loaded, thus
2933 overwriting the architecture dependent default
2936 - Frame Buffer Address:
2939 Define CONFIG_FB_ADDR if you want to use specific
2940 address for frame buffer. This is typically the case
2941 when using a graphics controller has separate video
2942 memory. U-Boot will then place the frame buffer at
2943 the given address instead of dynamically reserving it
2944 in system RAM by calling lcd_setmem(), which grabs
2945 the memory for the frame buffer depending on the
2946 configured panel size.
2948 Please see board_init_f function.
2950 - Automatic software updates via TFTP server
2952 CONFIG_UPDATE_TFTP_CNT_MAX
2953 CONFIG_UPDATE_TFTP_MSEC_MAX
2955 These options enable and control the auto-update feature;
2956 for a more detailed description refer to doc/README.update.
2958 - MTD Support (mtdparts command, UBI support)
2961 Adds the MTD device infrastructure from the Linux kernel.
2962 Needed for mtdparts command support.
2964 CONFIG_MTD_PARTITIONS
2966 Adds the MTD partitioning infrastructure from the Linux
2967 kernel. Needed for UBI support.
2972 Adds commands for interacting with MTD partitions formatted
2973 with the UBI flash translation layer
2975 Requires also defining CONFIG_RBTREE
2977 CONFIG_UBI_SILENCE_MSG
2979 Make the verbose messages from UBI stop printing. This leaves
2980 warnings and errors enabled.
2983 CONFIG_MTD_UBI_WL_THRESHOLD
2984 This parameter defines the maximum difference between the highest
2985 erase counter value and the lowest erase counter value of eraseblocks
2986 of UBI devices. When this threshold is exceeded, UBI starts performing
2987 wear leveling by means of moving data from eraseblock with low erase
2988 counter to eraseblocks with high erase counter.
2990 The default value should be OK for SLC NAND flashes, NOR flashes and
2991 other flashes which have eraseblock life-cycle 100000 or more.
2992 However, in case of MLC NAND flashes which typically have eraseblock
2993 life-cycle less than 10000, the threshold should be lessened (e.g.,
2994 to 128 or 256, although it does not have to be power of 2).
2998 CONFIG_MTD_UBI_BEB_LIMIT
2999 This option specifies the maximum bad physical eraseblocks UBI
3000 expects on the MTD device (per 1024 eraseblocks). If the
3001 underlying flash does not admit of bad eraseblocks (e.g. NOR
3002 flash), this value is ignored.
3004 NAND datasheets often specify the minimum and maximum NVM
3005 (Number of Valid Blocks) for the flashes' endurance lifetime.
3006 The maximum expected bad eraseblocks per 1024 eraseblocks
3007 then can be calculated as "1024 * (1 - MinNVB / MaxNVB)",
3008 which gives 20 for most NANDs (MaxNVB is basically the total
3009 count of eraseblocks on the chip).
3011 To put it differently, if this value is 20, UBI will try to
3012 reserve about 1.9% of physical eraseblocks for bad blocks
3013 handling. And that will be 1.9% of eraseblocks on the entire
3014 NAND chip, not just the MTD partition UBI attaches. This means
3015 that if you have, say, a NAND flash chip admits maximum 40 bad
3016 eraseblocks, and it is split on two MTD partitions of the same
3017 size, UBI will reserve 40 eraseblocks when attaching a
3022 CONFIG_MTD_UBI_FASTMAP
3023 Fastmap is a mechanism which allows attaching an UBI device
3024 in nearly constant time. Instead of scanning the whole MTD device it
3025 only has to locate a checkpoint (called fastmap) on the device.
3026 The on-flash fastmap contains all information needed to attach
3027 the device. Using fastmap makes only sense on large devices where
3028 attaching by scanning takes long. UBI will not automatically install
3029 a fastmap on old images, but you can set the UBI parameter
3030 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT to 1 if you want so. Please note
3031 that fastmap-enabled images are still usable with UBI implementations
3032 without fastmap support. On typical flash devices the whole fastmap
3033 fits into one PEB. UBI will reserve PEBs to hold two fastmaps.
3035 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT
3036 Set this parameter to enable fastmap automatically on images
3040 CONFIG_MTD_UBI_FM_DEBUG
3041 Enable UBI fastmap debug
3047 Adds commands for interacting with UBI volumes formatted as
3048 UBIFS. UBIFS is read-only in u-boot.
3050 Requires UBI support as well as CONFIG_LZO
3052 CONFIG_UBIFS_SILENCE_MSG
3054 Make the verbose messages from UBIFS stop printing. This leaves
3055 warnings and errors enabled.
3059 Enable building of SPL globally.
3062 LDSCRIPT for linking the SPL binary.
3064 CONFIG_SPL_MAX_FOOTPRINT
3065 Maximum size in memory allocated to the SPL, BSS included.
3066 When defined, the linker checks that the actual memory
3067 used by SPL from _start to __bss_end does not exceed it.
3068 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3069 must not be both defined at the same time.
3072 Maximum size of the SPL image (text, data, rodata, and
3073 linker lists sections), BSS excluded.
3074 When defined, the linker checks that the actual size does
3077 CONFIG_SPL_TEXT_BASE
3078 TEXT_BASE for linking the SPL binary.
3080 CONFIG_SPL_RELOC_TEXT_BASE
3081 Address to relocate to. If unspecified, this is equal to
3082 CONFIG_SPL_TEXT_BASE (i.e. no relocation is done).
3084 CONFIG_SPL_BSS_START_ADDR
3085 Link address for the BSS within the SPL binary.
3087 CONFIG_SPL_BSS_MAX_SIZE
3088 Maximum size in memory allocated to the SPL BSS.
3089 When defined, the linker checks that the actual memory used
3090 by SPL from __bss_start to __bss_end does not exceed it.
3091 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3092 must not be both defined at the same time.
3095 Adress of the start of the stack SPL will use
3097 CONFIG_SPL_PANIC_ON_RAW_IMAGE
3098 When defined, SPL will panic() if the image it has
3099 loaded does not have a signature.
3100 Defining this is useful when code which loads images
3101 in SPL cannot guarantee that absolutely all read errors
3103 An example is the LPC32XX MLC NAND driver, which will
3104 consider that a completely unreadable NAND block is bad,
3105 and thus should be skipped silently.
3107 CONFIG_SPL_RELOC_STACK
3108 Adress of the start of the stack SPL will use after
3109 relocation. If unspecified, this is equal to
3112 CONFIG_SYS_SPL_MALLOC_START
3113 Starting address of the malloc pool used in SPL.
3114 When this option is set the full malloc is used in SPL and
3115 it is set up by spl_init() and before that, the simple malloc()
3116 can be used if CONFIG_SYS_MALLOC_F is defined.
3118 CONFIG_SYS_SPL_MALLOC_SIZE
3119 The size of the malloc pool used in SPL.
3121 CONFIG_SPL_FRAMEWORK
3122 Enable the SPL framework under common/. This framework
3123 supports MMC, NAND and YMODEM loading of U-Boot and NAND
3124 NAND loading of the Linux Kernel.
3127 Enable booting directly to an OS from SPL.
3128 See also: doc/README.falcon
3130 CONFIG_SPL_DISPLAY_PRINT
3131 For ARM, enable an optional function to print more information
3132 about the running system.
3134 CONFIG_SPL_INIT_MINIMAL
3135 Arch init code should be built for a very small image
3137 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_PARTITION
3138 Partition on the MMC to load U-Boot from when the MMC is being
3141 CONFIG_SYS_MMCSD_RAW_MODE_KERNEL_SECTOR
3142 Sector to load kernel uImage from when MMC is being
3143 used in raw mode (for Falcon mode)
3145 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTOR,
3146 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTORS
3147 Sector and number of sectors to load kernel argument
3148 parameters from when MMC is being used in raw mode
3151 CONFIG_SYS_MMCSD_FS_BOOT_PARTITION
3152 Partition on the MMC to load U-Boot from when the MMC is being
3155 CONFIG_SPL_FS_LOAD_PAYLOAD_NAME
3156 Filename to read to load U-Boot when reading from filesystem
3158 CONFIG_SPL_FS_LOAD_KERNEL_NAME
3159 Filename to read to load kernel uImage when reading
3160 from filesystem (for Falcon mode)
3162 CONFIG_SPL_FS_LOAD_ARGS_NAME
3163 Filename to read to load kernel argument parameters
3164 when reading from filesystem (for Falcon mode)
3166 CONFIG_SPL_MPC83XX_WAIT_FOR_NAND
3167 Set this for NAND SPL on PPC mpc83xx targets, so that
3168 start.S waits for the rest of the SPL to load before
3169 continuing (the hardware starts execution after just
3170 loading the first page rather than the full 4K).
3172 CONFIG_SPL_SKIP_RELOCATE
3173 Avoid SPL relocation
3175 CONFIG_SPL_NAND_BASE
3176 Include nand_base.c in the SPL. Requires
3177 CONFIG_SPL_NAND_DRIVERS.
3179 CONFIG_SPL_NAND_DRIVERS
3180 SPL uses normal NAND drivers, not minimal drivers.
3183 Include standard software ECC in the SPL
3185 CONFIG_SPL_NAND_SIMPLE
3186 Support for NAND boot using simple NAND drivers that
3187 expose the cmd_ctrl() interface.
3190 Support for a lightweight UBI (fastmap) scanner and
3193 CONFIG_SPL_NAND_RAW_ONLY
3194 Support to boot only raw u-boot.bin images. Use this only
3195 if you need to save space.
3197 CONFIG_SPL_COMMON_INIT_DDR
3198 Set for common ddr init with serial presence detect in
3201 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
3202 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
3203 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
3204 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
3205 CONFIG_SYS_NAND_ECCBYTES
3206 Defines the size and behavior of the NAND that SPL uses
3209 CONFIG_SPL_NAND_BOOT
3210 Add support NAND boot
3212 CONFIG_SYS_NAND_U_BOOT_OFFS
3213 Location in NAND to read U-Boot from
3215 CONFIG_SYS_NAND_U_BOOT_DST
3216 Location in memory to load U-Boot to
3218 CONFIG_SYS_NAND_U_BOOT_SIZE
3219 Size of image to load
3221 CONFIG_SYS_NAND_U_BOOT_START
3222 Entry point in loaded image to jump to
3224 CONFIG_SYS_NAND_HW_ECC_OOBFIRST
3225 Define this if you need to first read the OOB and then the
3226 data. This is used, for example, on davinci platforms.
3228 CONFIG_SPL_OMAP3_ID_NAND
3229 Support for an OMAP3-specific set of functions to return the
3230 ID and MFR of the first attached NAND chip, if present.
3232 CONFIG_SPL_RAM_DEVICE
3233 Support for running image already present in ram, in SPL binary
3236 Image offset to which the SPL should be padded before appending
3237 the SPL payload. By default, this is defined as
3238 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3239 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3240 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3243 Final target image containing SPL and payload. Some SPLs
3244 use an arch-specific makefile fragment instead, for
3245 example if more than one image needs to be produced.
3247 CONFIG_FIT_SPL_PRINT
3248 Printing information about a FIT image adds quite a bit of
3249 code to SPL. So this is normally disabled in SPL. Use this
3250 option to re-enable it. This will affect the output of the
3251 bootm command when booting a FIT image.
3255 Enable building of TPL globally.
3258 Image offset to which the TPL should be padded before appending
3259 the TPL payload. By default, this is defined as
3260 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3261 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3262 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3264 - Interrupt support (PPC):
3266 There are common interrupt_init() and timer_interrupt()
3267 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
3268 for CPU specific initialization. interrupt_init_cpu()
3269 should set decrementer_count to appropriate value. If
3270 CPU resets decrementer automatically after interrupt
3271 (ppc4xx) it should set decrementer_count to zero.
3272 timer_interrupt() calls timer_interrupt_cpu() for CPU
3273 specific handling. If board has watchdog / status_led
3274 / other_activity_monitor it works automatically from
3275 general timer_interrupt().
3278 Board initialization settings:
3279 ------------------------------
3281 During Initialization u-boot calls a number of board specific functions
3282 to allow the preparation of board specific prerequisites, e.g. pin setup
3283 before drivers are initialized. To enable these callbacks the
3284 following configuration macros have to be defined. Currently this is
3285 architecture specific, so please check arch/your_architecture/lib/board.c
3286 typically in board_init_f() and board_init_r().
3288 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
3289 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
3290 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
3291 - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
3293 Configuration Settings:
3294 -----------------------
3296 - CONFIG_SYS_SUPPORT_64BIT_DATA: Defined automatically if compiled as 64-bit.
3297 Optionally it can be defined to support 64-bit memory commands.
3299 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
3300 undefine this when you're short of memory.
3302 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
3303 width of the commands listed in the 'help' command output.
3305 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
3306 prompt for user input.
3308 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
3310 - CONFIG_SYS_PBSIZE: Buffer size for Console output
3312 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
3314 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
3315 the application (usually a Linux kernel) when it is
3318 - CONFIG_SYS_BAUDRATE_TABLE:
3319 List of legal baudrate settings for this board.
3321 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
3322 Begin and End addresses of the area used by the
3325 - CONFIG_SYS_ALT_MEMTEST:
3326 Enable an alternate, more extensive memory test.
3328 - CONFIG_SYS_MEMTEST_SCRATCH:
3329 Scratch address used by the alternate memory test
3330 You only need to set this if address zero isn't writeable
3332 - CONFIG_SYS_MEM_RESERVE_SECURE
3333 Only implemented for ARMv8 for now.
3334 If defined, the size of CONFIG_SYS_MEM_RESERVE_SECURE memory
3335 is substracted from total RAM and won't be reported to OS.
3336 This memory can be used as secure memory. A variable
3337 gd->arch.secure_ram is used to track the location. In systems
3338 the RAM base is not zero, or RAM is divided into banks,
3339 this variable needs to be recalcuated to get the address.
3341 - CONFIG_SYS_MEM_TOP_HIDE:
3342 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
3343 this specified memory area will get subtracted from the top
3344 (end) of RAM and won't get "touched" at all by U-Boot. By
3345 fixing up gd->ram_size the Linux kernel should gets passed
3346 the now "corrected" memory size and won't touch it either.
3347 This should work for arch/ppc and arch/powerpc. Only Linux
3348 board ports in arch/powerpc with bootwrapper support that
3349 recalculate the memory size from the SDRAM controller setup
3350 will have to get fixed in Linux additionally.
3352 This option can be used as a workaround for the 440EPx/GRx
3353 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
3356 WARNING: Please make sure that this value is a multiple of
3357 the Linux page size (normally 4k). If this is not the case,
3358 then the end address of the Linux memory will be located at a
3359 non page size aligned address and this could cause major
3362 - CONFIG_SYS_LOADS_BAUD_CHANGE:
3363 Enable temporary baudrate change while serial download
3365 - CONFIG_SYS_SDRAM_BASE:
3366 Physical start address of SDRAM. _Must_ be 0 here.
3368 - CONFIG_SYS_FLASH_BASE:
3369 Physical start address of Flash memory.
3371 - CONFIG_SYS_MONITOR_BASE:
3372 Physical start address of boot monitor code (set by
3373 make config files to be same as the text base address
3374 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
3375 CONFIG_SYS_FLASH_BASE when booting from flash.
3377 - CONFIG_SYS_MONITOR_LEN:
3378 Size of memory reserved for monitor code, used to
3379 determine _at_compile_time_ (!) if the environment is
3380 embedded within the U-Boot image, or in a separate
3383 - CONFIG_SYS_MALLOC_LEN:
3384 Size of DRAM reserved for malloc() use.
3386 - CONFIG_SYS_MALLOC_F_LEN
3387 Size of the malloc() pool for use before relocation. If
3388 this is defined, then a very simple malloc() implementation
3389 will become available before relocation. The address is just
3390 below the global data, and the stack is moved down to make
3393 This feature allocates regions with increasing addresses
3394 within the region. calloc() is supported, but realloc()
3395 is not available. free() is supported but does nothing.
3396 The memory will be freed (or in fact just forgotten) when
3397 U-Boot relocates itself.
3399 - CONFIG_SYS_MALLOC_SIMPLE
3400 Provides a simple and small malloc() and calloc() for those
3401 boards which do not use the full malloc in SPL (which is
3402 enabled with CONFIG_SYS_SPL_MALLOC_START).
3404 - CONFIG_SYS_NONCACHED_MEMORY:
3405 Size of non-cached memory area. This area of memory will be
3406 typically located right below the malloc() area and mapped
3407 uncached in the MMU. This is useful for drivers that would
3408 otherwise require a lot of explicit cache maintenance. For
3409 some drivers it's also impossible to properly maintain the
3410 cache. For example if the regions that need to be flushed
3411 are not a multiple of the cache-line size, *and* padding
3412 cannot be allocated between the regions to align them (i.e.
3413 if the HW requires a contiguous array of regions, and the
3414 size of each region is not cache-aligned), then a flush of
3415 one region may result in overwriting data that hardware has
3416 written to another region in the same cache-line. This can
3417 happen for example in network drivers where descriptors for
3418 buffers are typically smaller than the CPU cache-line (e.g.
3419 16 bytes vs. 32 or 64 bytes).
3421 Non-cached memory is only supported on 32-bit ARM at present.
3423 - CONFIG_SYS_BOOTM_LEN:
3424 Normally compressed uImages are limited to an
3425 uncompressed size of 8 MBytes. If this is not enough,
3426 you can define CONFIG_SYS_BOOTM_LEN in your board config file
3427 to adjust this setting to your needs.
3429 - CONFIG_SYS_BOOTMAPSZ:
3430 Maximum size of memory mapped by the startup code of
3431 the Linux kernel; all data that must be processed by
3432 the Linux kernel (bd_info, boot arguments, FDT blob if
3433 used) must be put below this limit, unless "bootm_low"
3434 environment variable is defined and non-zero. In such case
3435 all data for the Linux kernel must be between "bootm_low"
3436 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
3437 variable "bootm_mapsize" will override the value of
3438 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
3439 then the value in "bootm_size" will be used instead.
3441 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
3442 Enable initrd_high functionality. If defined then the
3443 initrd_high feature is enabled and the bootm ramdisk subcommand
3446 - CONFIG_SYS_BOOT_GET_CMDLINE:
3447 Enables allocating and saving kernel cmdline in space between
3448 "bootm_low" and "bootm_low" + BOOTMAPSZ.
3450 - CONFIG_SYS_BOOT_GET_KBD:
3451 Enables allocating and saving a kernel copy of the bd_info in
3452 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
3454 - CONFIG_SYS_MAX_FLASH_BANKS:
3455 Max number of Flash memory banks
3457 - CONFIG_SYS_MAX_FLASH_SECT:
3458 Max number of sectors on a Flash chip
3460 - CONFIG_SYS_FLASH_ERASE_TOUT:
3461 Timeout for Flash erase operations (in ms)
3463 - CONFIG_SYS_FLASH_WRITE_TOUT:
3464 Timeout for Flash write operations (in ms)
3466 - CONFIG_SYS_FLASH_LOCK_TOUT
3467 Timeout for Flash set sector lock bit operation (in ms)
3469 - CONFIG_SYS_FLASH_UNLOCK_TOUT
3470 Timeout for Flash clear lock bits operation (in ms)
3472 - CONFIG_SYS_FLASH_PROTECTION
3473 If defined, hardware flash sectors protection is used
3474 instead of U-Boot software protection.
3476 - CONFIG_SYS_DIRECT_FLASH_TFTP:
3478 Enable TFTP transfers directly to flash memory;
3479 without this option such a download has to be
3480 performed in two steps: (1) download to RAM, and (2)
3481 copy from RAM to flash.
3483 The two-step approach is usually more reliable, since
3484 you can check if the download worked before you erase
3485 the flash, but in some situations (when system RAM is
3486 too limited to allow for a temporary copy of the
3487 downloaded image) this option may be very useful.
3489 - CONFIG_SYS_FLASH_CFI:
3490 Define if the flash driver uses extra elements in the
3491 common flash structure for storing flash geometry.
3493 - CONFIG_FLASH_CFI_DRIVER
3494 This option also enables the building of the cfi_flash driver
3495 in the drivers directory
3497 - CONFIG_FLASH_CFI_MTD
3498 This option enables the building of the cfi_mtd driver
3499 in the drivers directory. The driver exports CFI flash
3502 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
3503 Use buffered writes to flash.
3505 - CONFIG_FLASH_SPANSION_S29WS_N
3506 s29ws-n MirrorBit flash has non-standard addresses for buffered
3509 - CONFIG_SYS_FLASH_QUIET_TEST
3510 If this option is defined, the common CFI flash doesn't
3511 print it's warning upon not recognized FLASH banks. This
3512 is useful, if some of the configured banks are only
3513 optionally available.
3515 - CONFIG_FLASH_SHOW_PROGRESS
3516 If defined (must be an integer), print out countdown
3517 digits and dots. Recommended value: 45 (9..1) for 80
3518 column displays, 15 (3..1) for 40 column displays.
3520 - CONFIG_FLASH_VERIFY
3521 If defined, the content of the flash (destination) is compared
3522 against the source after the write operation. An error message
3523 will be printed when the contents are not identical.
3524 Please note that this option is useless in nearly all cases,
3525 since such flash programming errors usually are detected earlier
3526 while unprotecting/erasing/programming. Please only enable
3527 this option if you really know what you are doing.
3529 - CONFIG_SYS_RX_ETH_BUFFER:
3530 Defines the number of Ethernet receive buffers. On some
3531 Ethernet controllers it is recommended to set this value
3532 to 8 or even higher (EEPRO100 or 405 EMAC), since all
3533 buffers can be full shortly after enabling the interface
3534 on high Ethernet traffic.
3535 Defaults to 4 if not defined.
3537 - CONFIG_ENV_MAX_ENTRIES
3539 Maximum number of entries in the hash table that is used
3540 internally to store the environment settings. The default
3541 setting is supposed to be generous and should work in most
3542 cases. This setting can be used to tune behaviour; see
3543 lib/hashtable.c for details.
3545 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3546 - CONFIG_ENV_FLAGS_LIST_STATIC
3547 Enable validation of the values given to environment variables when
3548 calling env set. Variables can be restricted to only decimal,
3549 hexadecimal, or boolean. If CONFIG_CMD_NET is also defined,
3550 the variables can also be restricted to IP address or MAC address.
3552 The format of the list is:
3553 type_attribute = [s|d|x|b|i|m]
3554 access_attribute = [a|r|o|c]
3555 attributes = type_attribute[access_attribute]
3556 entry = variable_name[:attributes]
3559 The type attributes are:
3560 s - String (default)
3563 b - Boolean ([1yYtT|0nNfF])
3567 The access attributes are:
3573 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3574 Define this to a list (string) to define the ".flags"
3575 environment variable in the default or embedded environment.
3577 - CONFIG_ENV_FLAGS_LIST_STATIC
3578 Define this to a list (string) to define validation that
3579 should be done if an entry is not found in the ".flags"
3580 environment variable. To override a setting in the static
3581 list, simply add an entry for the same variable name to the
3584 If CONFIG_REGEX is defined, the variable_name above is evaluated as a
3585 regular expression. This allows multiple variables to define the same
3586 flags without explicitly listing them for each variable.
3588 - CONFIG_ENV_ACCESS_IGNORE_FORCE
3589 If defined, don't allow the -f switch to env set override variable
3593 If stdint.h is available with your toolchain you can define this
3594 option to enable it. You can provide option 'USE_STDINT=1' when
3595 building U-Boot to enable this.
3597 The following definitions that deal with the placement and management
3598 of environment data (variable area); in general, we support the
3599 following configurations:
3601 - CONFIG_BUILD_ENVCRC:
3603 Builds up envcrc with the target environment so that external utils
3604 may easily extract it and embed it in final U-Boot images.
3606 - CONFIG_ENV_IS_IN_FLASH:
3608 Define this if the environment is in flash memory.
3610 a) The environment occupies one whole flash sector, which is
3611 "embedded" in the text segment with the U-Boot code. This
3612 happens usually with "bottom boot sector" or "top boot
3613 sector" type flash chips, which have several smaller
3614 sectors at the start or the end. For instance, such a
3615 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
3616 such a case you would place the environment in one of the
3617 4 kB sectors - with U-Boot code before and after it. With
3618 "top boot sector" type flash chips, you would put the
3619 environment in one of the last sectors, leaving a gap
3620 between U-Boot and the environment.
3622 - CONFIG_ENV_OFFSET:
3624 Offset of environment data (variable area) to the
3625 beginning of flash memory; for instance, with bottom boot
3626 type flash chips the second sector can be used: the offset
3627 for this sector is given here.
3629 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
3633 This is just another way to specify the start address of
3634 the flash sector containing the environment (instead of
3637 - CONFIG_ENV_SECT_SIZE:
3639 Size of the sector containing the environment.
3642 b) Sometimes flash chips have few, equal sized, BIG sectors.
3643 In such a case you don't want to spend a whole sector for
3648 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
3649 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
3650 of this flash sector for the environment. This saves
3651 memory for the RAM copy of the environment.
3653 It may also save flash memory if you decide to use this
3654 when your environment is "embedded" within U-Boot code,
3655 since then the remainder of the flash sector could be used
3656 for U-Boot code. It should be pointed out that this is
3657 STRONGLY DISCOURAGED from a robustness point of view:
3658 updating the environment in flash makes it always
3659 necessary to erase the WHOLE sector. If something goes
3660 wrong before the contents has been restored from a copy in
3661 RAM, your target system will be dead.
3663 - CONFIG_ENV_ADDR_REDUND
3664 CONFIG_ENV_SIZE_REDUND
3666 These settings describe a second storage area used to hold
3667 a redundant copy of the environment data, so that there is
3668 a valid backup copy in case there is a power failure during
3669 a "saveenv" operation.
3671 BE CAREFUL! Any changes to the flash layout, and some changes to the
3672 source code will make it necessary to adapt <board>/u-boot.lds*
3676 - CONFIG_ENV_IS_IN_NVRAM:
3678 Define this if you have some non-volatile memory device
3679 (NVRAM, battery buffered SRAM) which you want to use for the
3685 These two #defines are used to determine the memory area you
3686 want to use for environment. It is assumed that this memory
3687 can just be read and written to, without any special
3690 BE CAREFUL! The first access to the environment happens quite early
3691 in U-Boot initialization (when we try to get the setting of for the
3692 console baudrate). You *MUST* have mapped your NVRAM area then, or
3695 Please note that even with NVRAM we still use a copy of the
3696 environment in RAM: we could work on NVRAM directly, but we want to
3697 keep settings there always unmodified except somebody uses "saveenv"
3698 to save the current settings.
3701 - CONFIG_ENV_IS_IN_EEPROM:
3703 Use this if you have an EEPROM or similar serial access
3704 device and a driver for it.
3706 - CONFIG_ENV_OFFSET:
3709 These two #defines specify the offset and size of the
3710 environment area within the total memory of your EEPROM.
3712 - CONFIG_SYS_I2C_EEPROM_ADDR:
3713 If defined, specified the chip address of the EEPROM device.
3714 The default address is zero.
3716 - CONFIG_SYS_I2C_EEPROM_BUS:
3717 If defined, specified the i2c bus of the EEPROM device.
3719 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
3720 If defined, the number of bits used to address bytes in a
3721 single page in the EEPROM device. A 64 byte page, for example
3722 would require six bits.
3724 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
3725 If defined, the number of milliseconds to delay between
3726 page writes. The default is zero milliseconds.
3728 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
3729 The length in bytes of the EEPROM memory array address. Note
3730 that this is NOT the chip address length!
3732 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
3733 EEPROM chips that implement "address overflow" are ones
3734 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
3735 address and the extra bits end up in the "chip address" bit
3736 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
3739 Note that we consider the length of the address field to
3740 still be one byte because the extra address bits are hidden
3741 in the chip address.
3743 - CONFIG_SYS_EEPROM_SIZE:
3744 The size in bytes of the EEPROM device.
3746 - CONFIG_ENV_EEPROM_IS_ON_I2C
3747 define this, if you have I2C and SPI activated, and your
3748 EEPROM, which holds the environment, is on the I2C bus.
3750 - CONFIG_I2C_ENV_EEPROM_BUS
3751 if you have an Environment on an EEPROM reached over
3752 I2C muxes, you can define here, how to reach this
3753 EEPROM. For example:
3755 #define CONFIG_I2C_ENV_EEPROM_BUS 1
3757 EEPROM which holds the environment, is reached over
3758 a pca9547 i2c mux with address 0x70, channel 3.
3760 - CONFIG_ENV_IS_IN_DATAFLASH:
3762 Define this if you have a DataFlash memory device which you
3763 want to use for the environment.
3765 - CONFIG_ENV_OFFSET:
3769 These three #defines specify the offset and size of the
3770 environment area within the total memory of your DataFlash placed
3771 at the specified address.
3773 - CONFIG_ENV_IS_IN_SPI_FLASH:
3775 Define this if you have a SPI Flash memory device which you
3776 want to use for the environment.
3778 - CONFIG_ENV_OFFSET:
3781 These two #defines specify the offset and size of the
3782 environment area within the SPI Flash. CONFIG_ENV_OFFSET must be
3783 aligned to an erase sector boundary.
3785 - CONFIG_ENV_SECT_SIZE:
3787 Define the SPI flash's sector size.
3789 - CONFIG_ENV_OFFSET_REDUND (optional):
3791 This setting describes a second storage area of CONFIG_ENV_SIZE
3792 size used to hold a redundant copy of the environment data, so
3793 that there is a valid backup copy in case there is a power failure
3794 during a "saveenv" operation. CONFIG_ENV_OFFSET_REDUND must be
3795 aligned to an erase sector boundary.
3797 - CONFIG_ENV_SPI_BUS (optional):
3798 - CONFIG_ENV_SPI_CS (optional):
3800 Define the SPI bus and chip select. If not defined they will be 0.
3802 - CONFIG_ENV_SPI_MAX_HZ (optional):
3804 Define the SPI max work clock. If not defined then use 1MHz.
3806 - CONFIG_ENV_SPI_MODE (optional):
3808 Define the SPI work mode. If not defined then use SPI_MODE_3.
3810 - CONFIG_ENV_IS_IN_REMOTE:
3812 Define this if you have a remote memory space which you
3813 want to use for the local device's environment.
3818 These two #defines specify the address and size of the
3819 environment area within the remote memory space. The
3820 local device can get the environment from remote memory
3821 space by SRIO or PCIE links.
3823 BE CAREFUL! For some special cases, the local device can not use
3824 "saveenv" command. For example, the local device will get the
3825 environment stored in a remote NOR flash by SRIO or PCIE link,
3826 but it can not erase, write this NOR flash by SRIO or PCIE interface.
3828 - CONFIG_ENV_IS_IN_NAND:
3830 Define this if you have a NAND device which you want to use
3831 for the environment.
3833 - CONFIG_ENV_OFFSET:
3836 These two #defines specify the offset and size of the environment
3837 area within the first NAND device. CONFIG_ENV_OFFSET must be
3838 aligned to an erase block boundary.
3840 - CONFIG_ENV_OFFSET_REDUND (optional):
3842 This setting describes a second storage area of CONFIG_ENV_SIZE
3843 size used to hold a redundant copy of the environment data, so
3844 that there is a valid backup copy in case there is a power failure
3845 during a "saveenv" operation. CONFIG_ENV_OFFSET_REDUND must be
3846 aligned to an erase block boundary.
3848 - CONFIG_ENV_RANGE (optional):
3850 Specifies the length of the region in which the environment
3851 can be written. This should be a multiple of the NAND device's
3852 block size. Specifying a range with more erase blocks than
3853 are needed to hold CONFIG_ENV_SIZE allows bad blocks within
3854 the range to be avoided.
3856 - CONFIG_ENV_OFFSET_OOB (optional):
3858 Enables support for dynamically retrieving the offset of the
3859 environment from block zero's out-of-band data. The
3860 "nand env.oob" command can be used to record this offset.
3861 Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
3862 using CONFIG_ENV_OFFSET_OOB.
3864 - CONFIG_NAND_ENV_DST
3866 Defines address in RAM to which the nand_spl code should copy the
3867 environment. If redundant environment is used, it will be copied to
3868 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
3870 - CONFIG_ENV_IS_IN_UBI:
3872 Define this if you have an UBI volume that you want to use for the
3873 environment. This has the benefit of wear-leveling the environment
3874 accesses, which is important on NAND.
3876 - CONFIG_ENV_UBI_PART:
3878 Define this to a string that is the mtd partition containing the UBI.
3880 - CONFIG_ENV_UBI_VOLUME:
3882 Define this to the name of the volume that you want to store the
3885 - CONFIG_ENV_UBI_VOLUME_REDUND:
3887 Define this to the name of another volume to store a second copy of
3888 the environment in. This will enable redundant environments in UBI.
3889 It is assumed that both volumes are in the same MTD partition.
3891 - CONFIG_UBI_SILENCE_MSG
3892 - CONFIG_UBIFS_SILENCE_MSG
3894 You will probably want to define these to avoid a really noisy system
3895 when storing the env in UBI.
3897 - CONFIG_ENV_IS_IN_FAT:
3898 Define this if you want to use the FAT file system for the environment.
3900 - FAT_ENV_INTERFACE:
3902 Define this to a string that is the name of the block device.
3904 - FAT_ENV_DEVICE_AND_PART:
3906 Define this to a string to specify the partition of the device. It can
3909 "D:P", "D:0", "D", "D:" or "D:auto" (D, P are integers. And P >= 1)
3910 - "D:P": device D partition P. Error occurs if device D has no
3913 - "D" or "D:": device D partition 1 if device D has partition
3914 table, or the whole device D if has no partition
3916 - "D:auto": first partition in device D with bootable flag set.
3917 If none, first valid partition in device D. If no
3918 partition table then means device D.
3922 It's a string of the FAT file name. This file use to store the
3926 This should be defined. Otherwise it cannot save the environment file.
3928 - CONFIG_ENV_IS_IN_MMC:
3930 Define this if you have an MMC device which you want to use for the
3933 - CONFIG_SYS_MMC_ENV_DEV:
3935 Specifies which MMC device the environment is stored in.
3937 - CONFIG_SYS_MMC_ENV_PART (optional):
3939 Specifies which MMC partition the environment is stored in. If not
3940 set, defaults to partition 0, the user area. Common values might be
3941 1 (first MMC boot partition), 2 (second MMC boot partition).
3943 - CONFIG_ENV_OFFSET:
3946 These two #defines specify the offset and size of the environment
3947 area within the specified MMC device.
3949 If offset is positive (the usual case), it is treated as relative to
3950 the start of the MMC partition. If offset is negative, it is treated
3951 as relative to the end of the MMC partition. This can be useful if
3952 your board may be fitted with different MMC devices, which have
3953 different sizes for the MMC partitions, and you always want the
3954 environment placed at the very end of the partition, to leave the
3955 maximum possible space before it, to store other data.
3957 These two values are in units of bytes, but must be aligned to an
3958 MMC sector boundary.
3960 - CONFIG_ENV_OFFSET_REDUND (optional):
3962 Specifies a second storage area, of CONFIG_ENV_SIZE size, used to
3963 hold a redundant copy of the environment data. This provides a
3964 valid backup copy in case the other copy is corrupted, e.g. due
3965 to a power failure during a "saveenv" operation.
3967 This value may also be positive or negative; this is handled in the
3968 same way as CONFIG_ENV_OFFSET.
3970 This value is also in units of bytes, but must also be aligned to
3971 an MMC sector boundary.
3973 - CONFIG_ENV_SIZE_REDUND (optional):
3975 This value need not be set, even when CONFIG_ENV_OFFSET_REDUND is
3976 set. If this value is set, it must be set to the same value as
3979 - CONFIG_SYS_SPI_INIT_OFFSET
3981 Defines offset to the initial SPI buffer area in DPRAM. The
3982 area is used at an early stage (ROM part) if the environment
3983 is configured to reside in the SPI EEPROM: We need a 520 byte
3984 scratch DPRAM area. It is used between the two initialization
3985 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
3986 to be a good choice since it makes it far enough from the
3987 start of the data area as well as from the stack pointer.
3989 Please note that the environment is read-only until the monitor
3990 has been relocated to RAM and a RAM copy of the environment has been
3991 created; also, when using EEPROM you will have to use getenv_f()
3992 until then to read environment variables.
3994 The environment is protected by a CRC32 checksum. Before the monitor
3995 is relocated into RAM, as a result of a bad CRC you will be working
3996 with the compiled-in default environment - *silently*!!! [This is
3997 necessary, because the first environment variable we need is the
3998 "baudrate" setting for the console - if we have a bad CRC, we don't
3999 have any device yet where we could complain.]
4001 Note: once the monitor has been relocated, then it will complain if
4002 the default environment is used; a new CRC is computed as soon as you
4003 use the "saveenv" command to store a valid environment.
4005 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
4006 Echo the inverted Ethernet link state to the fault LED.
4008 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
4009 also needs to be defined.
4011 - CONFIG_SYS_FAULT_MII_ADDR:
4012 MII address of the PHY to check for the Ethernet link state.
4014 - CONFIG_NS16550_MIN_FUNCTIONS:
4015 Define this if you desire to only have use of the NS16550_init
4016 and NS16550_putc functions for the serial driver located at
4017 drivers/serial/ns16550.c. This option is useful for saving
4018 space for already greatly restricted images, including but not
4019 limited to NAND_SPL configurations.
4021 - CONFIG_DISPLAY_BOARDINFO
4022 Display information about the board that U-Boot is running on
4023 when U-Boot starts up. The board function checkboard() is called
4026 - CONFIG_DISPLAY_BOARDINFO_LATE
4027 Similar to the previous option, but display this information
4028 later, once stdio is running and output goes to the LCD, if
4031 - CONFIG_BOARD_SIZE_LIMIT:
4032 Maximum size of the U-Boot image. When defined, the
4033 build system checks that the actual size does not
4036 Low Level (hardware related) configuration options:
4037 ---------------------------------------------------
4039 - CONFIG_SYS_CACHELINE_SIZE:
4040 Cache Line Size of the CPU.
4042 - CONFIG_SYS_DEFAULT_IMMR:
4043 Default address of the IMMR after system reset.
4045 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
4046 and RPXsuper) to be able to adjust the position of
4047 the IMMR register after a reset.
4049 - CONFIG_SYS_CCSRBAR_DEFAULT:
4050 Default (power-on reset) physical address of CCSR on Freescale
4053 - CONFIG_SYS_CCSRBAR:
4054 Virtual address of CCSR. On a 32-bit build, this is typically
4055 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
4057 CONFIG_SYS_DEFAULT_IMMR must also be set to this value,
4058 for cross-platform code that uses that macro instead.
4060 - CONFIG_SYS_CCSRBAR_PHYS:
4061 Physical address of CCSR. CCSR can be relocated to a new
4062 physical address, if desired. In this case, this macro should
4063 be set to that address. Otherwise, it should be set to the
4064 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
4065 is typically relocated on 36-bit builds. It is recommended
4066 that this macro be defined via the _HIGH and _LOW macros:
4068 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
4069 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
4071 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
4072 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
4073 either 0 (32-bit build) or 0xF (36-bit build). This macro is
4074 used in assembly code, so it must not contain typecasts or
4075 integer size suffixes (e.g. "ULL").
4077 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
4078 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
4079 used in assembly code, so it must not contain typecasts or
4080 integer size suffixes (e.g. "ULL").
4082 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
4083 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
4084 forced to a value that ensures that CCSR is not relocated.
4086 - Floppy Disk Support:
4087 CONFIG_SYS_FDC_DRIVE_NUMBER
4089 the default drive number (default value 0)
4091 CONFIG_SYS_ISA_IO_STRIDE
4093 defines the spacing between FDC chipset registers
4096 CONFIG_SYS_ISA_IO_OFFSET
4098 defines the offset of register from address. It
4099 depends on which part of the data bus is connected to
4100 the FDC chipset. (default value 0)
4102 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
4103 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
4106 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
4107 fdc_hw_init() is called at the beginning of the FDC
4108 setup. fdc_hw_init() must be provided by the board
4109 source code. It is used to make hardware-dependent
4113 Most IDE controllers were designed to be connected with PCI
4114 interface. Only few of them were designed for AHB interface.
4115 When software is doing ATA command and data transfer to
4116 IDE devices through IDE-AHB controller, some additional
4117 registers accessing to these kind of IDE-AHB controller
4120 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
4121 DO NOT CHANGE unless you know exactly what you're
4122 doing! (11-4) [MPC8xx/82xx systems only]
4124 - CONFIG_SYS_INIT_RAM_ADDR:
4126 Start address of memory area that can be used for
4127 initial data and stack; please note that this must be
4128 writable memory that is working WITHOUT special
4129 initialization, i. e. you CANNOT use normal RAM which
4130 will become available only after programming the
4131 memory controller and running certain initialization
4134 U-Boot uses the following memory types:
4135 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
4136 - MPC824X: data cache
4137 - PPC4xx: data cache
4139 - CONFIG_SYS_GBL_DATA_OFFSET:
4141 Offset of the initial data structure in the memory
4142 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
4143 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
4144 data is located at the end of the available space
4145 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
4146 GENERATED_GBL_DATA_SIZE), and the initial stack is just
4147 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
4148 CONFIG_SYS_GBL_DATA_OFFSET) downward.
4151 On the MPC824X (or other systems that use the data
4152 cache for initial memory) the address chosen for
4153 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
4154 point to an otherwise UNUSED address space between
4155 the top of RAM and the start of the PCI space.
4157 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
4159 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
4161 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
4163 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
4165 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
4167 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
4169 - CONFIG_SYS_OR_TIMING_SDRAM:
4172 - CONFIG_SYS_MAMR_PTA:
4173 periodic timer for refresh
4175 - CONFIG_SYS_DER: Debug Event Register (37-47)
4177 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
4178 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
4179 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
4180 CONFIG_SYS_BR1_PRELIM:
4181 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
4183 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
4184 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
4185 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
4186 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
4188 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
4189 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
4190 Machine Mode Register and Memory Periodic Timer
4191 Prescaler definitions (SDRAM timing)
4193 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
4194 enable I2C microcode relocation patch (MPC8xx);
4195 define relocation offset in DPRAM [DSP2]
4197 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
4198 enable SMC microcode relocation patch (MPC8xx);
4199 define relocation offset in DPRAM [SMC1]
4201 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
4202 enable SPI microcode relocation patch (MPC8xx);
4203 define relocation offset in DPRAM [SCC4]
4205 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
4206 Offset of the bootmode word in DPRAM used by post
4207 (Power On Self Tests). This definition overrides
4208 #define'd default value in commproc.h resp.
4211 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
4212 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
4213 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
4214 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
4215 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
4216 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
4217 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
4218 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
4219 Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
4221 - CONFIG_PCI_DISABLE_PCIE:
4222 Disable PCI-Express on systems where it is supported but not
4225 - CONFIG_PCI_ENUM_ONLY
4226 Only scan through and get the devices on the buses.
4227 Don't do any setup work, presumably because someone or
4228 something has already done it, and we don't need to do it
4229 a second time. Useful for platforms that are pre-booted
4230 by coreboot or similar.
4232 - CONFIG_PCI_INDIRECT_BRIDGE:
4233 Enable support for indirect PCI bridges.
4236 Chip has SRIO or not
4239 Board has SRIO 1 port available
4242 Board has SRIO 2 port available
4244 - CONFIG_SRIO_PCIE_BOOT_MASTER
4245 Board can support master function for Boot from SRIO and PCIE
4247 - CONFIG_SYS_SRIOn_MEM_VIRT:
4248 Virtual Address of SRIO port 'n' memory region
4250 - CONFIG_SYS_SRIOn_MEM_PHYS:
4251 Physical Address of SRIO port 'n' memory region
4253 - CONFIG_SYS_SRIOn_MEM_SIZE:
4254 Size of SRIO port 'n' memory region
4256 - CONFIG_SYS_NAND_BUSWIDTH_16BIT
4257 Defined to tell the NAND controller that the NAND chip is using
4259 Not all NAND drivers use this symbol.
4260 Example of drivers that use it:
4261 - drivers/mtd/nand/ndfc.c
4262 - drivers/mtd/nand/mxc_nand.c
4264 - CONFIG_SYS_NDFC_EBC0_CFG
4265 Sets the EBC0_CFG register for the NDFC. If not defined
4266 a default value will be used.
4269 Get DDR timing information from an I2C EEPROM. Common
4270 with pluggable memory modules such as SODIMMs
4273 I2C address of the SPD EEPROM
4275 - CONFIG_SYS_SPD_BUS_NUM
4276 If SPD EEPROM is on an I2C bus other than the first
4277 one, specify here. Note that the value must resolve
4278 to something your driver can deal with.
4280 - CONFIG_SYS_DDR_RAW_TIMING
4281 Get DDR timing information from other than SPD. Common with
4282 soldered DDR chips onboard without SPD. DDR raw timing
4283 parameters are extracted from datasheet and hard-coded into
4284 header files or board specific files.
4286 - CONFIG_FSL_DDR_INTERACTIVE
4287 Enable interactive DDR debugging. See doc/README.fsl-ddr.
4289 - CONFIG_FSL_DDR_SYNC_REFRESH
4290 Enable sync of refresh for multiple controllers.
4292 - CONFIG_FSL_DDR_BIST
4293 Enable built-in memory test for Freescale DDR controllers.
4295 - CONFIG_SYS_83XX_DDR_USES_CS0
4296 Only for 83xx systems. If specified, then DDR should
4297 be configured using CS0 and CS1 instead of CS2 and CS3.
4299 - CONFIG_ETHER_ON_FEC[12]
4300 Define to enable FEC[12] on a 8xx series processor.
4302 - CONFIG_FEC[12]_PHY
4303 Define to the hardcoded PHY address which corresponds
4304 to the given FEC; i. e.
4305 #define CONFIG_FEC1_PHY 4
4306 means that the PHY with address 4 is connected to FEC1
4308 When set to -1, means to probe for first available.
4310 - CONFIG_FEC[12]_PHY_NORXERR
4311 The PHY does not have a RXERR line (RMII only).
4312 (so program the FEC to ignore it).
4315 Enable RMII mode for all FECs.
4316 Note that this is a global option, we can't
4317 have one FEC in standard MII mode and another in RMII mode.
4319 - CONFIG_CRC32_VERIFY
4320 Add a verify option to the crc32 command.
4323 => crc32 -v <address> <count> <crc32>
4325 Where address/count indicate a memory area
4326 and crc32 is the correct crc32 which the
4330 Add the "loopw" memory command. This only takes effect if
4331 the memory commands are activated globally (CONFIG_CMD_MEM).
4334 Add the "mdc" and "mwc" memory commands. These are cyclic
4339 This command will print 4 bytes (10,11,12,13) each 500 ms.
4341 => mwc.l 100 12345678 10
4342 This command will write 12345678 to address 100 all 10 ms.
4344 This only takes effect if the memory commands are activated
4345 globally (CONFIG_CMD_MEM).
4347 - CONFIG_SKIP_LOWLEVEL_INIT
4348 [ARM, NDS32, MIPS only] If this variable is defined, then certain
4349 low level initializations (like setting up the memory
4350 controller) are omitted and/or U-Boot does not
4351 relocate itself into RAM.
4353 Normally this variable MUST NOT be defined. The only
4354 exception is when U-Boot is loaded (to RAM) by some
4355 other boot loader or by a debugger which performs
4356 these initializations itself.
4358 - CONFIG_SKIP_LOWLEVEL_INIT_ONLY
4359 [ARM926EJ-S only] This allows just the call to lowlevel_init()
4360 to be skipped. The normal CP15 init (such as enabling the
4361 instruction cache) is still performed.
4364 Modifies the behaviour of start.S when compiling a loader
4365 that is executed before the actual U-Boot. E.g. when
4366 compiling a NAND SPL.
4369 Modifies the behaviour of start.S when compiling a loader
4370 that is executed after the SPL and before the actual U-Boot.
4371 It is loaded by the SPL.
4373 - CONFIG_SYS_MPC85XX_NO_RESETVEC
4374 Only for 85xx systems. If this variable is specified, the section
4375 .resetvec is not kept and the section .bootpg is placed in the
4376 previous 4k of the .text section.
4378 - CONFIG_ARCH_MAP_SYSMEM
4379 Generally U-Boot (and in particular the md command) uses
4380 effective address. It is therefore not necessary to regard
4381 U-Boot address as virtual addresses that need to be translated
4382 to physical addresses. However, sandbox requires this, since
4383 it maintains its own little RAM buffer which contains all
4384 addressable memory. This option causes some memory accesses
4385 to be mapped through map_sysmem() / unmap_sysmem().
4387 - CONFIG_X86_RESET_VECTOR
4388 If defined, the x86 reset vector code is included. This is not
4389 needed when U-Boot is running from Coreboot.
4391 - CONFIG_SPL_AM33XX_ENABLE_RTC32K_OSC:
4392 Enables the RTC32K OSC on AM33xx based plattforms
4394 - CONFIG_SYS_NAND_NO_SUBPAGE_WRITE
4395 Option to disable subpage write in NAND driver
4396 driver that uses this:
4397 drivers/mtd/nand/davinci_nand.c
4399 Freescale QE/FMAN Firmware Support:
4400 -----------------------------------
4402 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
4403 loading of "firmware", which is encoded in the QE firmware binary format.
4404 This firmware often needs to be loaded during U-Boot booting, so macros
4405 are used to identify the storage device (NOR flash, SPI, etc) and the address
4408 - CONFIG_SYS_FMAN_FW_ADDR
4409 The address in the storage device where the FMAN microcode is located. The
4410 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4413 - CONFIG_SYS_QE_FW_ADDR
4414 The address in the storage device where the QE microcode is located. The
4415 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4418 - CONFIG_SYS_QE_FMAN_FW_LENGTH
4419 The maximum possible size of the firmware. The firmware binary format
4420 has a field that specifies the actual size of the firmware, but it
4421 might not be possible to read any part of the firmware unless some
4422 local storage is allocated to hold the entire firmware first.
4424 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
4425 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
4426 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
4427 virtual address in NOR flash.
4429 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
4430 Specifies that QE/FMAN firmware is located in NAND flash.
4431 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
4433 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
4434 Specifies that QE/FMAN firmware is located on the primary SD/MMC
4435 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
4437 - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
4438 Specifies that QE/FMAN firmware is located in the remote (master)
4439 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
4440 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
4441 window->master inbound window->master LAW->the ucode address in
4442 master's memory space.
4444 Freescale Layerscape Management Complex Firmware Support:
4445 ---------------------------------------------------------
4446 The Freescale Layerscape Management Complex (MC) supports the loading of
4448 This firmware often needs to be loaded during U-Boot booting, so macros
4449 are used to identify the storage device (NOR flash, SPI, etc) and the address
4452 - CONFIG_FSL_MC_ENET
4453 Enable the MC driver for Layerscape SoCs.
4455 Freescale Layerscape Debug Server Support:
4456 -------------------------------------------
4457 The Freescale Layerscape Debug Server Support supports the loading of
4458 "Debug Server firmware" and triggering SP boot-rom.
4459 This firmware often needs to be loaded during U-Boot booting.
4461 - CONFIG_SYS_MC_RSV_MEM_ALIGN
4462 Define alignment of reserved memory MC requires
4467 In order to achieve reproducible builds, timestamps used in the U-Boot build
4468 process have to be set to a fixed value.
4470 This is done using the SOURCE_DATE_EPOCH environment variable.
4471 SOURCE_DATE_EPOCH is to be set on the build host's shell, not as a configuration
4472 option for U-Boot or an environment variable in U-Boot.
4474 SOURCE_DATE_EPOCH should be set to a number of seconds since the epoch, in UTC.
4476 Building the Software:
4477 ======================
4479 Building U-Boot has been tested in several native build environments
4480 and in many different cross environments. Of course we cannot support
4481 all possibly existing versions of cross development tools in all
4482 (potentially obsolete) versions. In case of tool chain problems we
4483 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
4484 which is extensively used to build and test U-Boot.
4486 If you are not using a native environment, it is assumed that you
4487 have GNU cross compiling tools available in your path. In this case,
4488 you must set the environment variable CROSS_COMPILE in your shell.
4489 Note that no changes to the Makefile or any other source files are
4490 necessary. For example using the ELDK on a 4xx CPU, please enter:
4492 $ CROSS_COMPILE=ppc_4xx-
4493 $ export CROSS_COMPILE
4495 Note: If you wish to generate Windows versions of the utilities in
4496 the tools directory you can use the MinGW toolchain
4497 (http://www.mingw.org). Set your HOST tools to the MinGW
4498 toolchain and execute 'make tools'. For example:
4500 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
4502 Binaries such as tools/mkimage.exe will be created which can
4503 be executed on computers running Windows.
4505 U-Boot is intended to be simple to build. After installing the
4506 sources you must configure U-Boot for one specific board type. This
4511 where "NAME_defconfig" is the name of one of the existing configu-
4512 rations; see boards.cfg for supported names.
4514 Note: for some board special configuration names may exist; check if
4515 additional information is available from the board vendor; for
4516 instance, the TQM823L systems are available without (standard)
4517 or with LCD support. You can select such additional "features"
4518 when choosing the configuration, i. e.
4520 make TQM823L_defconfig
4521 - will configure for a plain TQM823L, i. e. no LCD support
4523 make TQM823L_LCD_defconfig
4524 - will configure for a TQM823L with U-Boot console on LCD
4529 Finally, type "make all", and you should get some working U-Boot
4530 images ready for download to / installation on your system:
4532 - "u-boot.bin" is a raw binary image
4533 - "u-boot" is an image in ELF binary format
4534 - "u-boot.srec" is in Motorola S-Record format
4536 By default the build is performed locally and the objects are saved
4537 in the source directory. One of the two methods can be used to change
4538 this behavior and build U-Boot to some external directory:
4540 1. Add O= to the make command line invocations:
4542 make O=/tmp/build distclean
4543 make O=/tmp/build NAME_defconfig
4544 make O=/tmp/build all
4546 2. Set environment variable KBUILD_OUTPUT to point to the desired location:
4548 export KBUILD_OUTPUT=/tmp/build
4553 Note that the command line "O=" setting overrides the KBUILD_OUTPUT environment
4557 Please be aware that the Makefiles assume you are using GNU make, so
4558 for instance on NetBSD you might need to use "gmake" instead of
4562 If the system board that you have is not listed, then you will need
4563 to port U-Boot to your hardware platform. To do this, follow these
4566 1. Create a new directory to hold your board specific code. Add any
4567 files you need. In your board directory, you will need at least
4568 the "Makefile" and a "<board>.c".
4569 2. Create a new configuration file "include/configs/<board>.h" for
4571 3. If you're porting U-Boot to a new CPU, then also create a new
4572 directory to hold your CPU specific code. Add any files you need.
4573 4. Run "make <board>_defconfig" with your new name.
4574 5. Type "make", and you should get a working "u-boot.srec" file
4575 to be installed on your target system.
4576 6. Debug and solve any problems that might arise.
4577 [Of course, this last step is much harder than it sounds.]
4580 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
4581 ==============================================================
4583 If you have modified U-Boot sources (for instance added a new board
4584 or support for new devices, a new CPU, etc.) you are expected to
4585 provide feedback to the other developers. The feedback normally takes
4586 the form of a "patch", i. e. a context diff against a certain (latest
4587 official or latest in the git repository) version of U-Boot sources.
4589 But before you submit such a patch, please verify that your modifi-
4590 cation did not break existing code. At least make sure that *ALL* of
4591 the supported boards compile WITHOUT ANY compiler warnings. To do so,
4592 just run the buildman script (tools/buildman/buildman), which will
4593 configure and build U-Boot for ALL supported system. Be warned, this
4594 will take a while. Please see the buildman README, or run 'buildman -H'
4598 See also "U-Boot Porting Guide" below.
4601 Monitor Commands - Overview:
4602 ============================
4604 go - start application at address 'addr'
4605 run - run commands in an environment variable
4606 bootm - boot application image from memory
4607 bootp - boot image via network using BootP/TFTP protocol
4608 bootz - boot zImage from memory
4609 tftpboot- boot image via network using TFTP protocol
4610 and env variables "ipaddr" and "serverip"
4611 (and eventually "gatewayip")
4612 tftpput - upload a file via network using TFTP protocol
4613 rarpboot- boot image via network using RARP/TFTP protocol
4614 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
4615 loads - load S-Record file over serial line
4616 loadb - load binary file over serial line (kermit mode)
4618 mm - memory modify (auto-incrementing)
4619 nm - memory modify (constant address)
4620 mw - memory write (fill)
4622 cmp - memory compare
4623 crc32 - checksum calculation
4624 i2c - I2C sub-system
4625 sspi - SPI utility commands
4626 base - print or set address offset
4627 printenv- print environment variables
4628 setenv - set environment variables
4629 saveenv - save environment variables to persistent storage
4630 protect - enable or disable FLASH write protection
4631 erase - erase FLASH memory
4632 flinfo - print FLASH memory information
4633 nand - NAND memory operations (see doc/README.nand)
4634 bdinfo - print Board Info structure
4635 iminfo - print header information for application image
4636 coninfo - print console devices and informations
4637 ide - IDE sub-system
4638 loop - infinite loop on address range
4639 loopw - infinite write loop on address range
4640 mtest - simple RAM test
4641 icache - enable or disable instruction cache
4642 dcache - enable or disable data cache
4643 reset - Perform RESET of the CPU
4644 echo - echo args to console
4645 version - print monitor version
4646 help - print online help
4647 ? - alias for 'help'
4650 Monitor Commands - Detailed Description:
4651 ========================================
4655 For now: just type "help <command>".
4658 Environment Variables:
4659 ======================
4661 U-Boot supports user configuration using Environment Variables which
4662 can be made persistent by saving to Flash memory.
4664 Environment Variables are set using "setenv", printed using
4665 "printenv", and saved to Flash using "saveenv". Using "setenv"
4666 without a value can be used to delete a variable from the
4667 environment. As long as you don't save the environment you are
4668 working with an in-memory copy. In case the Flash area containing the
4669 environment is erased by accident, a default environment is provided.
4671 Some configuration options can be set using Environment Variables.
4673 List of environment variables (most likely not complete):
4675 baudrate - see CONFIG_BAUDRATE
4677 bootdelay - see CONFIG_BOOTDELAY
4679 bootcmd - see CONFIG_BOOTCOMMAND
4681 bootargs - Boot arguments when booting an RTOS image
4683 bootfile - Name of the image to load with TFTP
4685 bootm_low - Memory range available for image processing in the bootm
4686 command can be restricted. This variable is given as
4687 a hexadecimal number and defines lowest address allowed
4688 for use by the bootm command. See also "bootm_size"
4689 environment variable. Address defined by "bootm_low" is
4690 also the base of the initial memory mapping for the Linux
4691 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
4694 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
4695 This variable is given as a hexadecimal number and it
4696 defines the size of the memory region starting at base
4697 address bootm_low that is accessible by the Linux kernel
4698 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
4699 as the default value if it is defined, and bootm_size is
4702 bootm_size - Memory range available for image processing in the bootm
4703 command can be restricted. This variable is given as
4704 a hexadecimal number and defines the size of the region
4705 allowed for use by the bootm command. See also "bootm_low"
4706 environment variable.
4708 updatefile - Location of the software update file on a TFTP server, used
4709 by the automatic software update feature. Please refer to
4710 documentation in doc/README.update for more details.
4712 autoload - if set to "no" (any string beginning with 'n'),
4713 "bootp" will just load perform a lookup of the
4714 configuration from the BOOTP server, but not try to
4715 load any image using TFTP
4717 autostart - if set to "yes", an image loaded using the "bootp",
4718 "rarpboot", "tftpboot" or "diskboot" commands will
4719 be automatically started (by internally calling
4722 If set to "no", a standalone image passed to the
4723 "bootm" command will be copied to the load address
4724 (and eventually uncompressed), but NOT be started.
4725 This can be used to load and uncompress arbitrary
4728 fdt_high - if set this restricts the maximum address that the
4729 flattened device tree will be copied into upon boot.
4730 For example, if you have a system with 1 GB memory
4731 at physical address 0x10000000, while Linux kernel
4732 only recognizes the first 704 MB as low memory, you
4733 may need to set fdt_high as 0x3C000000 to have the
4734 device tree blob be copied to the maximum address
4735 of the 704 MB low memory, so that Linux kernel can
4736 access it during the boot procedure.
4738 If this is set to the special value 0xFFFFFFFF then
4739 the fdt will not be copied at all on boot. For this
4740 to work it must reside in writable memory, have
4741 sufficient padding on the end of it for u-boot to
4742 add the information it needs into it, and the memory
4743 must be accessible by the kernel.
4745 fdtcontroladdr- if set this is the address of the control flattened
4746 device tree used by U-Boot when CONFIG_OF_CONTROL is
4749 i2cfast - (PPC405GP|PPC405EP only)
4750 if set to 'y' configures Linux I2C driver for fast
4751 mode (400kHZ). This environment variable is used in
4752 initialization code. So, for changes to be effective
4753 it must be saved and board must be reset.
4755 initrd_high - restrict positioning of initrd images:
4756 If this variable is not set, initrd images will be
4757 copied to the highest possible address in RAM; this
4758 is usually what you want since it allows for
4759 maximum initrd size. If for some reason you want to
4760 make sure that the initrd image is loaded below the
4761 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
4762 variable to a value of "no" or "off" or "0".
4763 Alternatively, you can set it to a maximum upper
4764 address to use (U-Boot will still check that it
4765 does not overwrite the U-Boot stack and data).
4767 For instance, when you have a system with 16 MB
4768 RAM, and want to reserve 4 MB from use by Linux,
4769 you can do this by adding "mem=12M" to the value of
4770 the "bootargs" variable. However, now you must make
4771 sure that the initrd image is placed in the first
4772 12 MB as well - this can be done with
4774 setenv initrd_high 00c00000
4776 If you set initrd_high to 0xFFFFFFFF, this is an
4777 indication to U-Boot that all addresses are legal
4778 for the Linux kernel, including addresses in flash
4779 memory. In this case U-Boot will NOT COPY the
4780 ramdisk at all. This may be useful to reduce the
4781 boot time on your system, but requires that this
4782 feature is supported by your Linux kernel.
4784 ipaddr - IP address; needed for tftpboot command
4786 loadaddr - Default load address for commands like "bootp",
4787 "rarpboot", "tftpboot", "loadb" or "diskboot"
4789 loads_echo - see CONFIG_LOADS_ECHO
4791 serverip - TFTP server IP address; needed for tftpboot command
4793 bootretry - see CONFIG_BOOT_RETRY_TIME
4795 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
4797 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
4799 ethprime - controls which interface is used first.
4801 ethact - controls which interface is currently active.
4802 For example you can do the following
4804 => setenv ethact FEC
4805 => ping 192.168.0.1 # traffic sent on FEC
4806 => setenv ethact SCC
4807 => ping 10.0.0.1 # traffic sent on SCC
4809 ethrotate - When set to "no" U-Boot does not go through all
4810 available network interfaces.
4811 It just stays at the currently selected interface.
4813 netretry - When set to "no" each network operation will
4814 either succeed or fail without retrying.
4815 When set to "once" the network operation will
4816 fail when all the available network interfaces
4817 are tried once without success.
4818 Useful on scripts which control the retry operation
4821 npe_ucode - set load address for the NPE microcode
4823 silent_linux - If set then Linux will be told to boot silently, by
4824 changing the console to be empty. If "yes" it will be
4825 made silent. If "no" it will not be made silent. If
4826 unset, then it will be made silent if the U-Boot console
4829 tftpsrcp - If this is set, the value is used for TFTP's
4832 tftpdstp - If this is set, the value is used for TFTP's UDP
4833 destination port instead of the Well Know Port 69.
4835 tftpblocksize - Block size to use for TFTP transfers; if not set,
4836 we use the TFTP server's default block size
4838 tftptimeout - Retransmission timeout for TFTP packets (in milli-
4839 seconds, minimum value is 1000 = 1 second). Defines
4840 when a packet is considered to be lost so it has to
4841 be retransmitted. The default is 5000 = 5 seconds.
4842 Lowering this value may make downloads succeed
4843 faster in networks with high packet loss rates or
4844 with unreliable TFTP servers.
4846 tftptimeoutcountmax - maximum count of TFTP timeouts (no
4847 unit, minimum value = 0). Defines how many timeouts
4848 can happen during a single file transfer before that
4849 transfer is aborted. The default is 10, and 0 means
4850 'no timeouts allowed'. Increasing this value may help
4851 downloads succeed with high packet loss rates, or with
4852 unreliable TFTP servers or client hardware.
4854 vlan - When set to a value < 4095 the traffic over
4855 Ethernet is encapsulated/received over 802.1q
4858 bootpretryperiod - Period during which BOOTP/DHCP sends retries.
4859 Unsigned value, in milliseconds. If not set, the period will
4860 be either the default (28000), or a value based on
4861 CONFIG_NET_RETRY_COUNT, if defined. This value has
4862 precedence over the valu based on CONFIG_NET_RETRY_COUNT.
4864 The following image location variables contain the location of images
4865 used in booting. The "Image" column gives the role of the image and is
4866 not an environment variable name. The other columns are environment
4867 variable names. "File Name" gives the name of the file on a TFTP
4868 server, "RAM Address" gives the location in RAM the image will be
4869 loaded to, and "Flash Location" gives the image's address in NOR
4870 flash or offset in NAND flash.
4872 *Note* - these variables don't have to be defined for all boards, some
4873 boards currently use other variables for these purposes, and some
4874 boards use these variables for other purposes.
4876 Image File Name RAM Address Flash Location
4877 ----- --------- ----------- --------------
4878 u-boot u-boot u-boot_addr_r u-boot_addr
4879 Linux kernel bootfile kernel_addr_r kernel_addr
4880 device tree blob fdtfile fdt_addr_r fdt_addr
4881 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
4883 The following environment variables may be used and automatically
4884 updated by the network boot commands ("bootp" and "rarpboot"),
4885 depending the information provided by your boot server:
4887 bootfile - see above
4888 dnsip - IP address of your Domain Name Server
4889 dnsip2 - IP address of your secondary Domain Name Server
4890 gatewayip - IP address of the Gateway (Router) to use
4891 hostname - Target hostname
4893 netmask - Subnet Mask
4894 rootpath - Pathname of the root filesystem on the NFS server
4895 serverip - see above
4898 There are two special Environment Variables:
4900 serial# - contains hardware identification information such
4901 as type string and/or serial number
4902 ethaddr - Ethernet address
4904 These variables can be set only once (usually during manufacturing of
4905 the board). U-Boot refuses to delete or overwrite these variables
4906 once they have been set once.
4909 Further special Environment Variables:
4911 ver - Contains the U-Boot version string as printed
4912 with the "version" command. This variable is
4913 readonly (see CONFIG_VERSION_VARIABLE).
4916 Please note that changes to some configuration parameters may take
4917 only effect after the next boot (yes, that's just like Windoze :-).
4920 Callback functions for environment variables:
4921 ---------------------------------------------
4923 For some environment variables, the behavior of u-boot needs to change
4924 when their values are changed. This functionality allows functions to
4925 be associated with arbitrary variables. On creation, overwrite, or
4926 deletion, the callback will provide the opportunity for some side
4927 effect to happen or for the change to be rejected.
4929 The callbacks are named and associated with a function using the
4930 U_BOOT_ENV_CALLBACK macro in your board or driver code.
4932 These callbacks are associated with variables in one of two ways. The
4933 static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC
4934 in the board configuration to a string that defines a list of
4935 associations. The list must be in the following format:
4937 entry = variable_name[:callback_name]
4940 If the callback name is not specified, then the callback is deleted.
4941 Spaces are also allowed anywhere in the list.
4943 Callbacks can also be associated by defining the ".callbacks" variable
4944 with the same list format above. Any association in ".callbacks" will
4945 override any association in the static list. You can define
4946 CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the
4947 ".callbacks" environment variable in the default or embedded environment.
4949 If CONFIG_REGEX is defined, the variable_name above is evaluated as a
4950 regular expression. This allows multiple variables to be connected to
4951 the same callback without explicitly listing them all out.
4954 Command Line Parsing:
4955 =====================
4957 There are two different command line parsers available with U-Boot:
4958 the old "simple" one, and the much more powerful "hush" shell:
4960 Old, simple command line parser:
4961 --------------------------------
4963 - supports environment variables (through setenv / saveenv commands)
4964 - several commands on one line, separated by ';'
4965 - variable substitution using "... ${name} ..." syntax
4966 - special characters ('$', ';') can be escaped by prefixing with '\',
4968 setenv bootcmd bootm \${address}
4969 - You can also escape text by enclosing in single apostrophes, for example:
4970 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
4975 - similar to Bourne shell, with control structures like
4976 if...then...else...fi, for...do...done; while...do...done,
4977 until...do...done, ...
4978 - supports environment ("global") variables (through setenv / saveenv
4979 commands) and local shell variables (through standard shell syntax
4980 "name=value"); only environment variables can be used with "run"
4986 (1) If a command line (or an environment variable executed by a "run"
4987 command) contains several commands separated by semicolon, and
4988 one of these commands fails, then the remaining commands will be
4991 (2) If you execute several variables with one call to run (i. e.
4992 calling run with a list of variables as arguments), any failing
4993 command will cause "run" to terminate, i. e. the remaining
4994 variables are not executed.
4996 Note for Redundant Ethernet Interfaces:
4997 =======================================
4999 Some boards come with redundant Ethernet interfaces; U-Boot supports
5000 such configurations and is capable of automatic selection of a
5001 "working" interface when needed. MAC assignment works as follows:
5003 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
5004 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
5005 "eth1addr" (=>eth1), "eth2addr", ...
5007 If the network interface stores some valid MAC address (for instance
5008 in SROM), this is used as default address if there is NO correspon-
5009 ding setting in the environment; if the corresponding environment
5010 variable is set, this overrides the settings in the card; that means:
5012 o If the SROM has a valid MAC address, and there is no address in the
5013 environment, the SROM's address is used.
5015 o If there is no valid address in the SROM, and a definition in the
5016 environment exists, then the value from the environment variable is
5019 o If both the SROM and the environment contain a MAC address, and
5020 both addresses are the same, this MAC address is used.
5022 o If both the SROM and the environment contain a MAC address, and the
5023 addresses differ, the value from the environment is used and a
5026 o If neither SROM nor the environment contain a MAC address, an error
5027 is raised. If CONFIG_NET_RANDOM_ETHADDR is defined, then in this case
5028 a random, locally-assigned MAC is used.
5030 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
5031 will be programmed into hardware as part of the initialization process. This
5032 may be skipped by setting the appropriate 'ethmacskip' environment variable.
5033 The naming convention is as follows:
5034 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
5039 U-Boot is capable of booting (and performing other auxiliary operations on)
5040 images in two formats:
5042 New uImage format (FIT)
5043 -----------------------
5045 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
5046 to Flattened Device Tree). It allows the use of images with multiple
5047 components (several kernels, ramdisks, etc.), with contents protected by
5048 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
5054 Old image format is based on binary files which can be basically anything,
5055 preceded by a special header; see the definitions in include/image.h for
5056 details; basically, the header defines the following image properties:
5058 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
5059 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
5060 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
5061 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
5063 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
5064 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
5065 Currently supported: ARM, AVR32, Intel x86, MIPS, NDS32, Nios II, PowerPC).
5066 * Compression Type (uncompressed, gzip, bzip2)
5072 The header is marked by a special Magic Number, and both the header
5073 and the data portions of the image are secured against corruption by
5080 Although U-Boot should support any OS or standalone application
5081 easily, the main focus has always been on Linux during the design of
5084 U-Boot includes many features that so far have been part of some
5085 special "boot loader" code within the Linux kernel. Also, any
5086 "initrd" images to be used are no longer part of one big Linux image;
5087 instead, kernel and "initrd" are separate images. This implementation
5088 serves several purposes:
5090 - the same features can be used for other OS or standalone
5091 applications (for instance: using compressed images to reduce the
5092 Flash memory footprint)
5094 - it becomes much easier to port new Linux kernel versions because
5095 lots of low-level, hardware dependent stuff are done by U-Boot
5097 - the same Linux kernel image can now be used with different "initrd"
5098 images; of course this also means that different kernel images can
5099 be run with the same "initrd". This makes testing easier (you don't
5100 have to build a new "zImage.initrd" Linux image when you just
5101 change a file in your "initrd"). Also, a field-upgrade of the
5102 software is easier now.
5108 Porting Linux to U-Boot based systems:
5109 ---------------------------------------
5111 U-Boot cannot save you from doing all the necessary modifications to
5112 configure the Linux device drivers for use with your target hardware
5113 (no, we don't intend to provide a full virtual machine interface to
5116 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
5118 Just make sure your machine specific header file (for instance
5119 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
5120 Information structure as we define in include/asm-<arch>/u-boot.h,
5121 and make sure that your definition of IMAP_ADDR uses the same value
5122 as your U-Boot configuration in CONFIG_SYS_IMMR.
5124 Note that U-Boot now has a driver model, a unified model for drivers.
5125 If you are adding a new driver, plumb it into driver model. If there
5126 is no uclass available, you are encouraged to create one. See
5130 Configuring the Linux kernel:
5131 -----------------------------
5133 No specific requirements for U-Boot. Make sure you have some root
5134 device (initial ramdisk, NFS) for your target system.
5137 Building a Linux Image:
5138 -----------------------
5140 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
5141 not used. If you use recent kernel source, a new build target
5142 "uImage" will exist which automatically builds an image usable by
5143 U-Boot. Most older kernels also have support for a "pImage" target,
5144 which was introduced for our predecessor project PPCBoot and uses a
5145 100% compatible format.
5149 make TQM850L_defconfig
5154 The "uImage" build target uses a special tool (in 'tools/mkimage') to
5155 encapsulate a compressed Linux kernel image with header information,
5156 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
5158 * build a standard "vmlinux" kernel image (in ELF binary format):
5160 * convert the kernel into a raw binary image:
5162 ${CROSS_COMPILE}-objcopy -O binary \
5163 -R .note -R .comment \
5164 -S vmlinux linux.bin
5166 * compress the binary image:
5170 * package compressed binary image for U-Boot:
5172 mkimage -A ppc -O linux -T kernel -C gzip \
5173 -a 0 -e 0 -n "Linux Kernel Image" \
5174 -d linux.bin.gz uImage
5177 The "mkimage" tool can also be used to create ramdisk images for use
5178 with U-Boot, either separated from the Linux kernel image, or
5179 combined into one file. "mkimage" encapsulates the images with a 64
5180 byte header containing information about target architecture,
5181 operating system, image type, compression method, entry points, time
5182 stamp, CRC32 checksums, etc.
5184 "mkimage" can be called in two ways: to verify existing images and
5185 print the header information, or to build new images.
5187 In the first form (with "-l" option) mkimage lists the information
5188 contained in the header of an existing U-Boot image; this includes
5189 checksum verification:
5191 tools/mkimage -l image
5192 -l ==> list image header information
5194 The second form (with "-d" option) is used to build a U-Boot image
5195 from a "data file" which is used as image payload:
5197 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
5198 -n name -d data_file image
5199 -A ==> set architecture to 'arch'
5200 -O ==> set operating system to 'os'
5201 -T ==> set image type to 'type'
5202 -C ==> set compression type 'comp'
5203 -a ==> set load address to 'addr' (hex)
5204 -e ==> set entry point to 'ep' (hex)
5205 -n ==> set image name to 'name'
5206 -d ==> use image data from 'datafile'
5208 Right now, all Linux kernels for PowerPC systems use the same load
5209 address (0x00000000), but the entry point address depends on the
5212 - 2.2.x kernels have the entry point at 0x0000000C,
5213 - 2.3.x and later kernels have the entry point at 0x00000000.
5215 So a typical call to build a U-Boot image would read:
5217 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5218 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
5219 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
5220 > examples/uImage.TQM850L
5221 Image Name: 2.4.4 kernel for TQM850L
5222 Created: Wed Jul 19 02:34:59 2000
5223 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5224 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5225 Load Address: 0x00000000
5226 Entry Point: 0x00000000
5228 To verify the contents of the image (or check for corruption):
5230 -> tools/mkimage -l examples/uImage.TQM850L
5231 Image Name: 2.4.4 kernel for TQM850L
5232 Created: Wed Jul 19 02:34:59 2000
5233 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5234 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5235 Load Address: 0x00000000
5236 Entry Point: 0x00000000
5238 NOTE: for embedded systems where boot time is critical you can trade
5239 speed for memory and install an UNCOMPRESSED image instead: this
5240 needs more space in Flash, but boots much faster since it does not
5241 need to be uncompressed:
5243 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
5244 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5245 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
5246 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
5247 > examples/uImage.TQM850L-uncompressed
5248 Image Name: 2.4.4 kernel for TQM850L
5249 Created: Wed Jul 19 02:34:59 2000
5250 Image Type: PowerPC Linux Kernel Image (uncompressed)
5251 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
5252 Load Address: 0x00000000
5253 Entry Point: 0x00000000
5256 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
5257 when your kernel is intended to use an initial ramdisk:
5259 -> tools/mkimage -n 'Simple Ramdisk Image' \
5260 > -A ppc -O linux -T ramdisk -C gzip \
5261 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
5262 Image Name: Simple Ramdisk Image
5263 Created: Wed Jan 12 14:01:50 2000
5264 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5265 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
5266 Load Address: 0x00000000
5267 Entry Point: 0x00000000
5269 The "dumpimage" is a tool to disassemble images built by mkimage. Its "-i"
5270 option performs the converse operation of the mkimage's second form (the "-d"
5271 option). Given an image built by mkimage, the dumpimage extracts a "data file"
5274 tools/dumpimage -i image -T type -p position data_file
5275 -i ==> extract from the 'image' a specific 'data_file'
5276 -T ==> set image type to 'type'
5277 -p ==> 'position' (starting at 0) of the 'data_file' inside the 'image'
5280 Installing a Linux Image:
5281 -------------------------
5283 To downloading a U-Boot image over the serial (console) interface,
5284 you must convert the image to S-Record format:
5286 objcopy -I binary -O srec examples/image examples/image.srec
5288 The 'objcopy' does not understand the information in the U-Boot
5289 image header, so the resulting S-Record file will be relative to
5290 address 0x00000000. To load it to a given address, you need to
5291 specify the target address as 'offset' parameter with the 'loads'
5294 Example: install the image to address 0x40100000 (which on the
5295 TQM8xxL is in the first Flash bank):
5297 => erase 40100000 401FFFFF
5303 ## Ready for S-Record download ...
5304 ~>examples/image.srec
5305 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
5307 15989 15990 15991 15992
5308 [file transfer complete]
5310 ## Start Addr = 0x00000000
5313 You can check the success of the download using the 'iminfo' command;
5314 this includes a checksum verification so you can be sure no data
5315 corruption happened:
5319 ## Checking Image at 40100000 ...
5320 Image Name: 2.2.13 for initrd on TQM850L
5321 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5322 Data Size: 335725 Bytes = 327 kB = 0 MB
5323 Load Address: 00000000
5324 Entry Point: 0000000c
5325 Verifying Checksum ... OK
5331 The "bootm" command is used to boot an application that is stored in
5332 memory (RAM or Flash). In case of a Linux kernel image, the contents
5333 of the "bootargs" environment variable is passed to the kernel as
5334 parameters. You can check and modify this variable using the
5335 "printenv" and "setenv" commands:
5338 => printenv bootargs
5339 bootargs=root=/dev/ram
5341 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5343 => printenv bootargs
5344 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5347 ## Booting Linux kernel at 40020000 ...
5348 Image Name: 2.2.13 for NFS on TQM850L
5349 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5350 Data Size: 381681 Bytes = 372 kB = 0 MB
5351 Load Address: 00000000
5352 Entry Point: 0000000c
5353 Verifying Checksum ... OK
5354 Uncompressing Kernel Image ... OK
5355 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
5356 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5357 time_init: decrementer frequency = 187500000/60
5358 Calibrating delay loop... 49.77 BogoMIPS
5359 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
5362 If you want to boot a Linux kernel with initial RAM disk, you pass
5363 the memory addresses of both the kernel and the initrd image (PPBCOOT
5364 format!) to the "bootm" command:
5366 => imi 40100000 40200000
5368 ## Checking Image at 40100000 ...
5369 Image Name: 2.2.13 for initrd on TQM850L
5370 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5371 Data Size: 335725 Bytes = 327 kB = 0 MB
5372 Load Address: 00000000
5373 Entry Point: 0000000c
5374 Verifying Checksum ... OK
5376 ## Checking Image at 40200000 ...
5377 Image Name: Simple Ramdisk Image
5378 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5379 Data Size: 566530 Bytes = 553 kB = 0 MB
5380 Load Address: 00000000
5381 Entry Point: 00000000
5382 Verifying Checksum ... OK
5384 => bootm 40100000 40200000
5385 ## Booting Linux kernel at 40100000 ...
5386 Image Name: 2.2.13 for initrd on TQM850L
5387 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5388 Data Size: 335725 Bytes = 327 kB = 0 MB
5389 Load Address: 00000000
5390 Entry Point: 0000000c
5391 Verifying Checksum ... OK
5392 Uncompressing Kernel Image ... OK
5393 ## Loading RAMDisk Image at 40200000 ...
5394 Image Name: Simple Ramdisk Image
5395 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5396 Data Size: 566530 Bytes = 553 kB = 0 MB
5397 Load Address: 00000000
5398 Entry Point: 00000000
5399 Verifying Checksum ... OK
5400 Loading Ramdisk ... OK
5401 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
5402 Boot arguments: root=/dev/ram
5403 time_init: decrementer frequency = 187500000/60
5404 Calibrating delay loop... 49.77 BogoMIPS
5406 RAMDISK: Compressed image found at block 0
5407 VFS: Mounted root (ext2 filesystem).
5411 Boot Linux and pass a flat device tree:
5414 First, U-Boot must be compiled with the appropriate defines. See the section
5415 titled "Linux Kernel Interface" above for a more in depth explanation. The
5416 following is an example of how to start a kernel and pass an updated
5422 oft=oftrees/mpc8540ads.dtb
5423 => tftp $oftaddr $oft
5424 Speed: 1000, full duplex
5426 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
5427 Filename 'oftrees/mpc8540ads.dtb'.
5428 Load address: 0x300000
5431 Bytes transferred = 4106 (100a hex)
5432 => tftp $loadaddr $bootfile
5433 Speed: 1000, full duplex
5435 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
5437 Load address: 0x200000
5438 Loading:############
5440 Bytes transferred = 1029407 (fb51f hex)
5445 => bootm $loadaddr - $oftaddr
5446 ## Booting image at 00200000 ...
5447 Image Name: Linux-2.6.17-dirty
5448 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5449 Data Size: 1029343 Bytes = 1005.2 kB
5450 Load Address: 00000000
5451 Entry Point: 00000000
5452 Verifying Checksum ... OK
5453 Uncompressing Kernel Image ... OK
5454 Booting using flat device tree at 0x300000
5455 Using MPC85xx ADS machine description
5456 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
5460 More About U-Boot Image Types:
5461 ------------------------------
5463 U-Boot supports the following image types:
5465 "Standalone Programs" are directly runnable in the environment
5466 provided by U-Boot; it is expected that (if they behave
5467 well) you can continue to work in U-Boot after return from
5468 the Standalone Program.
5469 "OS Kernel Images" are usually images of some Embedded OS which
5470 will take over control completely. Usually these programs
5471 will install their own set of exception handlers, device
5472 drivers, set up the MMU, etc. - this means, that you cannot
5473 expect to re-enter U-Boot except by resetting the CPU.
5474 "RAMDisk Images" are more or less just data blocks, and their
5475 parameters (address, size) are passed to an OS kernel that is
5477 "Multi-File Images" contain several images, typically an OS
5478 (Linux) kernel image and one or more data images like
5479 RAMDisks. This construct is useful for instance when you want
5480 to boot over the network using BOOTP etc., where the boot
5481 server provides just a single image file, but you want to get
5482 for instance an OS kernel and a RAMDisk image.
5484 "Multi-File Images" start with a list of image sizes, each
5485 image size (in bytes) specified by an "uint32_t" in network
5486 byte order. This list is terminated by an "(uint32_t)0".
5487 Immediately after the terminating 0 follow the images, one by
5488 one, all aligned on "uint32_t" boundaries (size rounded up to
5489 a multiple of 4 bytes).
5491 "Firmware Images" are binary images containing firmware (like
5492 U-Boot or FPGA images) which usually will be programmed to
5495 "Script files" are command sequences that will be executed by
5496 U-Boot's command interpreter; this feature is especially
5497 useful when you configure U-Boot to use a real shell (hush)
5498 as command interpreter.
5500 Booting the Linux zImage:
5501 -------------------------
5503 On some platforms, it's possible to boot Linux zImage. This is done
5504 using the "bootz" command. The syntax of "bootz" command is the same
5505 as the syntax of "bootm" command.
5507 Note, defining the CONFIG_SUPPORT_RAW_INITRD allows user to supply
5508 kernel with raw initrd images. The syntax is slightly different, the
5509 address of the initrd must be augmented by it's size, in the following
5510 format: "<initrd addres>:<initrd size>".
5516 One of the features of U-Boot is that you can dynamically load and
5517 run "standalone" applications, which can use some resources of
5518 U-Boot like console I/O functions or interrupt services.
5520 Two simple examples are included with the sources:
5525 'examples/hello_world.c' contains a small "Hello World" Demo
5526 application; it is automatically compiled when you build U-Boot.
5527 It's configured to run at address 0x00040004, so you can play with it
5531 ## Ready for S-Record download ...
5532 ~>examples/hello_world.srec
5533 1 2 3 4 5 6 7 8 9 10 11 ...
5534 [file transfer complete]
5536 ## Start Addr = 0x00040004
5538 => go 40004 Hello World! This is a test.
5539 ## Starting application at 0x00040004 ...
5550 Hit any key to exit ...
5552 ## Application terminated, rc = 0x0
5554 Another example, which demonstrates how to register a CPM interrupt
5555 handler with the U-Boot code, can be found in 'examples/timer.c'.
5556 Here, a CPM timer is set up to generate an interrupt every second.
5557 The interrupt service routine is trivial, just printing a '.'
5558 character, but this is just a demo program. The application can be
5559 controlled by the following keys:
5561 ? - print current values og the CPM Timer registers
5562 b - enable interrupts and start timer
5563 e - stop timer and disable interrupts
5564 q - quit application
5567 ## Ready for S-Record download ...
5568 ~>examples/timer.srec
5569 1 2 3 4 5 6 7 8 9 10 11 ...
5570 [file transfer complete]
5572 ## Start Addr = 0x00040004
5575 ## Starting application at 0x00040004 ...
5578 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
5581 [q, b, e, ?] Set interval 1000000 us
5584 [q, b, e, ?] ........
5585 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
5588 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
5591 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
5594 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
5596 [q, b, e, ?] ...Stopping timer
5598 [q, b, e, ?] ## Application terminated, rc = 0x0
5604 Over time, many people have reported problems when trying to use the
5605 "minicom" terminal emulation program for serial download. I (wd)
5606 consider minicom to be broken, and recommend not to use it. Under
5607 Unix, I recommend to use C-Kermit for general purpose use (and
5608 especially for kermit binary protocol download ("loadb" command), and
5609 use "cu" for S-Record download ("loads" command). See
5610 http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
5611 for help with kermit.
5614 Nevertheless, if you absolutely want to use it try adding this
5615 configuration to your "File transfer protocols" section:
5617 Name Program Name U/D FullScr IO-Red. Multi
5618 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
5619 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
5625 Starting at version 0.9.2, U-Boot supports NetBSD both as host
5626 (build U-Boot) and target system (boots NetBSD/mpc8xx).
5628 Building requires a cross environment; it is known to work on
5629 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
5630 need gmake since the Makefiles are not compatible with BSD make).
5631 Note that the cross-powerpc package does not install include files;
5632 attempting to build U-Boot will fail because <machine/ansi.h> is
5633 missing. This file has to be installed and patched manually:
5635 # cd /usr/pkg/cross/powerpc-netbsd/include
5637 # ln -s powerpc machine
5638 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
5639 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
5641 Native builds *don't* work due to incompatibilities between native
5642 and U-Boot include files.
5644 Booting assumes that (the first part of) the image booted is a
5645 stage-2 loader which in turn loads and then invokes the kernel
5646 proper. Loader sources will eventually appear in the NetBSD source
5647 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
5648 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
5651 Implementation Internals:
5652 =========================
5654 The following is not intended to be a complete description of every
5655 implementation detail. However, it should help to understand the
5656 inner workings of U-Boot and make it easier to port it to custom
5660 Initial Stack, Global Data:
5661 ---------------------------
5663 The implementation of U-Boot is complicated by the fact that U-Boot
5664 starts running out of ROM (flash memory), usually without access to
5665 system RAM (because the memory controller is not initialized yet).
5666 This means that we don't have writable Data or BSS segments, and BSS
5667 is not initialized as zero. To be able to get a C environment working
5668 at all, we have to allocate at least a minimal stack. Implementation
5669 options for this are defined and restricted by the CPU used: Some CPU
5670 models provide on-chip memory (like the IMMR area on MPC8xx and
5671 MPC826x processors), on others (parts of) the data cache can be
5672 locked as (mis-) used as memory, etc.
5674 Chris Hallinan posted a good summary of these issues to the
5675 U-Boot mailing list:
5677 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
5678 From: "Chris Hallinan" <clh@net1plus.com>
5679 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
5682 Correct me if I'm wrong, folks, but the way I understand it
5683 is this: Using DCACHE as initial RAM for Stack, etc, does not
5684 require any physical RAM backing up the cache. The cleverness
5685 is that the cache is being used as a temporary supply of
5686 necessary storage before the SDRAM controller is setup. It's
5687 beyond the scope of this list to explain the details, but you
5688 can see how this works by studying the cache architecture and
5689 operation in the architecture and processor-specific manuals.
5691 OCM is On Chip Memory, which I believe the 405GP has 4K. It
5692 is another option for the system designer to use as an
5693 initial stack/RAM area prior to SDRAM being available. Either
5694 option should work for you. Using CS 4 should be fine if your
5695 board designers haven't used it for something that would
5696 cause you grief during the initial boot! It is frequently not
5699 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
5700 with your processor/board/system design. The default value
5701 you will find in any recent u-boot distribution in
5702 walnut.h should work for you. I'd set it to a value larger
5703 than your SDRAM module. If you have a 64MB SDRAM module, set
5704 it above 400_0000. Just make sure your board has no resources
5705 that are supposed to respond to that address! That code in
5706 start.S has been around a while and should work as is when
5707 you get the config right.
5712 It is essential to remember this, since it has some impact on the C
5713 code for the initialization procedures:
5715 * Initialized global data (data segment) is read-only. Do not attempt
5718 * Do not use any uninitialized global data (or implicitly initialized
5719 as zero data - BSS segment) at all - this is undefined, initiali-
5720 zation is performed later (when relocating to RAM).
5722 * Stack space is very limited. Avoid big data buffers or things like
5725 Having only the stack as writable memory limits means we cannot use
5726 normal global data to share information between the code. But it
5727 turned out that the implementation of U-Boot can be greatly
5728 simplified by making a global data structure (gd_t) available to all
5729 functions. We could pass a pointer to this data as argument to _all_
5730 functions, but this would bloat the code. Instead we use a feature of
5731 the GCC compiler (Global Register Variables) to share the data: we
5732 place a pointer (gd) to the global data into a register which we
5733 reserve for this purpose.
5735 When choosing a register for such a purpose we are restricted by the
5736 relevant (E)ABI specifications for the current architecture, and by
5737 GCC's implementation.
5739 For PowerPC, the following registers have specific use:
5741 R2: reserved for system use
5742 R3-R4: parameter passing and return values
5743 R5-R10: parameter passing
5744 R13: small data area pointer
5748 (U-Boot also uses R12 as internal GOT pointer. r12
5749 is a volatile register so r12 needs to be reset when
5750 going back and forth between asm and C)
5752 ==> U-Boot will use R2 to hold a pointer to the global data
5754 Note: on PPC, we could use a static initializer (since the
5755 address of the global data structure is known at compile time),
5756 but it turned out that reserving a register results in somewhat
5757 smaller code - although the code savings are not that big (on
5758 average for all boards 752 bytes for the whole U-Boot image,
5759 624 text + 127 data).
5761 On ARM, the following registers are used:
5763 R0: function argument word/integer result
5764 R1-R3: function argument word
5765 R9: platform specific
5766 R10: stack limit (used only if stack checking is enabled)
5767 R11: argument (frame) pointer
5768 R12: temporary workspace
5771 R15: program counter
5773 ==> U-Boot will use R9 to hold a pointer to the global data
5775 Note: on ARM, only R_ARM_RELATIVE relocations are supported.
5777 On Nios II, the ABI is documented here:
5778 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
5780 ==> U-Boot will use gp to hold a pointer to the global data
5782 Note: on Nios II, we give "-G0" option to gcc and don't use gp
5783 to access small data sections, so gp is free.
5785 On NDS32, the following registers are used:
5787 R0-R1: argument/return
5789 R15: temporary register for assembler
5790 R16: trampoline register
5791 R28: frame pointer (FP)
5792 R29: global pointer (GP)
5793 R30: link register (LP)
5794 R31: stack pointer (SP)
5795 PC: program counter (PC)
5797 ==> U-Boot will use R10 to hold a pointer to the global data
5799 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
5800 or current versions of GCC may "optimize" the code too much.
5805 U-Boot runs in system state and uses physical addresses, i.e. the
5806 MMU is not used either for address mapping nor for memory protection.
5808 The available memory is mapped to fixed addresses using the memory
5809 controller. In this process, a contiguous block is formed for each
5810 memory type (Flash, SDRAM, SRAM), even when it consists of several
5811 physical memory banks.
5813 U-Boot is installed in the first 128 kB of the first Flash bank (on
5814 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
5815 booting and sizing and initializing DRAM, the code relocates itself
5816 to the upper end of DRAM. Immediately below the U-Boot code some
5817 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
5818 configuration setting]. Below that, a structure with global Board
5819 Info data is placed, followed by the stack (growing downward).
5821 Additionally, some exception handler code is copied to the low 8 kB
5822 of DRAM (0x00000000 ... 0x00001FFF).
5824 So a typical memory configuration with 16 MB of DRAM could look like
5827 0x0000 0000 Exception Vector code
5830 0x0000 2000 Free for Application Use
5836 0x00FB FF20 Monitor Stack (Growing downward)
5837 0x00FB FFAC Board Info Data and permanent copy of global data
5838 0x00FC 0000 Malloc Arena
5841 0x00FE 0000 RAM Copy of Monitor Code
5842 ... eventually: LCD or video framebuffer
5843 ... eventually: pRAM (Protected RAM - unchanged by reset)
5844 0x00FF FFFF [End of RAM]
5847 System Initialization:
5848 ----------------------
5850 In the reset configuration, U-Boot starts at the reset entry point
5851 (on most PowerPC systems at address 0x00000100). Because of the reset
5852 configuration for CS0# this is a mirror of the on board Flash memory.
5853 To be able to re-map memory U-Boot then jumps to its link address.
5854 To be able to implement the initialization code in C, a (small!)
5855 initial stack is set up in the internal Dual Ported RAM (in case CPUs
5856 which provide such a feature like MPC8xx or MPC8260), or in a locked
5857 part of the data cache. After that, U-Boot initializes the CPU core,
5858 the caches and the SIU.
5860 Next, all (potentially) available memory banks are mapped using a
5861 preliminary mapping. For example, we put them on 512 MB boundaries
5862 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
5863 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
5864 programmed for SDRAM access. Using the temporary configuration, a
5865 simple memory test is run that determines the size of the SDRAM
5868 When there is more than one SDRAM bank, and the banks are of
5869 different size, the largest is mapped first. For equal size, the first
5870 bank (CS2#) is mapped first. The first mapping is always for address
5871 0x00000000, with any additional banks following immediately to create
5872 contiguous memory starting from 0.
5874 Then, the monitor installs itself at the upper end of the SDRAM area
5875 and allocates memory for use by malloc() and for the global Board
5876 Info data; also, the exception vector code is copied to the low RAM
5877 pages, and the final stack is set up.
5879 Only after this relocation will you have a "normal" C environment;
5880 until that you are restricted in several ways, mostly because you are
5881 running from ROM, and because the code will have to be relocated to a
5885 U-Boot Porting Guide:
5886 ----------------------
5888 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
5892 int main(int argc, char *argv[])
5894 sighandler_t no_more_time;
5896 signal(SIGALRM, no_more_time);
5897 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
5899 if (available_money > available_manpower) {
5900 Pay consultant to port U-Boot;
5904 Download latest U-Boot source;
5906 Subscribe to u-boot mailing list;
5909 email("Hi, I am new to U-Boot, how do I get started?");
5912 Read the README file in the top level directory;
5913 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
5914 Read applicable doc/*.README;
5915 Read the source, Luke;
5916 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
5919 if (available_money > toLocalCurrency ($2500))
5922 Add a lot of aggravation and time;
5924 if (a similar board exists) { /* hopefully... */
5925 cp -a board/<similar> board/<myboard>
5926 cp include/configs/<similar>.h include/configs/<myboard>.h
5928 Create your own board support subdirectory;
5929 Create your own board include/configs/<myboard>.h file;
5931 Edit new board/<myboard> files
5932 Edit new include/configs/<myboard>.h
5937 Add / modify source code;
5941 email("Hi, I am having problems...");
5943 Send patch file to the U-Boot email list;
5944 if (reasonable critiques)
5945 Incorporate improvements from email list code review;
5947 Defend code as written;
5953 void no_more_time (int sig)
5962 All contributions to U-Boot should conform to the Linux kernel
5963 coding style; see the file "Documentation/CodingStyle" and the script
5964 "scripts/Lindent" in your Linux kernel source directory.
5966 Source files originating from a different project (for example the
5967 MTD subsystem) are generally exempt from these guidelines and are not
5968 reformatted to ease subsequent migration to newer versions of those
5971 Please note that U-Boot is implemented in C (and to some small parts in
5972 Assembler); no C++ is used, so please do not use C++ style comments (//)
5975 Please also stick to the following formatting rules:
5976 - remove any trailing white space
5977 - use TAB characters for indentation and vertical alignment, not spaces
5978 - make sure NOT to use DOS '\r\n' line feeds
5979 - do not add more than 2 consecutive empty lines to source files
5980 - do not add trailing empty lines to source files
5982 Submissions which do not conform to the standards may be returned
5983 with a request to reformat the changes.
5989 Since the number of patches for U-Boot is growing, we need to
5990 establish some rules. Submissions which do not conform to these rules
5991 may be rejected, even when they contain important and valuable stuff.
5993 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
5995 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
5996 see http://lists.denx.de/mailman/listinfo/u-boot
5998 When you send a patch, please include the following information with
6001 * For bug fixes: a description of the bug and how your patch fixes
6002 this bug. Please try to include a way of demonstrating that the
6003 patch actually fixes something.
6005 * For new features: a description of the feature and your
6008 * A CHANGELOG entry as plaintext (separate from the patch)
6010 * For major contributions, add a MAINTAINERS file with your
6011 information and associated file and directory references.
6013 * When you add support for a new board, don't forget to add a
6014 maintainer e-mail address to the boards.cfg file, too.
6016 * If your patch adds new configuration options, don't forget to
6017 document these in the README file.
6019 * The patch itself. If you are using git (which is *strongly*
6020 recommended) you can easily generate the patch using the
6021 "git format-patch". If you then use "git send-email" to send it to
6022 the U-Boot mailing list, you will avoid most of the common problems
6023 with some other mail clients.
6025 If you cannot use git, use "diff -purN OLD NEW". If your version of
6026 diff does not support these options, then get the latest version of
6029 The current directory when running this command shall be the parent
6030 directory of the U-Boot source tree (i. e. please make sure that
6031 your patch includes sufficient directory information for the
6034 We prefer patches as plain text. MIME attachments are discouraged,
6035 and compressed attachments must not be used.
6037 * If one logical set of modifications affects or creates several
6038 files, all these changes shall be submitted in a SINGLE patch file.
6040 * Changesets that contain different, unrelated modifications shall be
6041 submitted as SEPARATE patches, one patch per changeset.
6046 * Before sending the patch, run the buildman script on your patched
6047 source tree and make sure that no errors or warnings are reported
6048 for any of the boards.
6050 * Keep your modifications to the necessary minimum: A patch
6051 containing several unrelated changes or arbitrary reformats will be
6052 returned with a request to re-formatting / split it.
6054 * If you modify existing code, make sure that your new code does not
6055 add to the memory footprint of the code ;-) Small is beautiful!
6056 When adding new features, these should compile conditionally only
6057 (using #ifdef), and the resulting code with the new feature
6058 disabled must not need more memory than the old code without your
6061 * Remember that there is a size limit of 100 kB per message on the
6062 u-boot mailing list. Bigger patches will be moderated. If they are
6063 reasonable and not too big, they will be acknowledged. But patches
6064 bigger than the size limit should be avoided.