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_FLAGS * display details about env flags
837 CONFIG_CMD_ENV_EXISTS * check existence of env variable
838 CONFIG_CMD_EXPORTENV * export the environment
839 CONFIG_CMD_EXT2 * ext2 command support
840 CONFIG_CMD_EXT4 * ext4 command support
841 CONFIG_CMD_FS_GENERIC * filesystem commands (e.g. load, ls)
842 that work for multiple fs types
843 CONFIG_CMD_FS_UUID * Look up a filesystem UUID
844 CONFIG_CMD_SAVEENV saveenv
845 CONFIG_CMD_FDC * Floppy Disk Support
846 CONFIG_CMD_FAT * FAT command support
847 CONFIG_CMD_FLASH flinfo, erase, protect
848 CONFIG_CMD_FPGA FPGA device initialization support
849 CONFIG_CMD_FUSE * Device fuse support
850 CONFIG_CMD_GETTIME * Get time since boot
851 CONFIG_CMD_GO * the 'go' command (exec code)
852 CONFIG_CMD_GREPENV * search environment
853 CONFIG_CMD_HASH * calculate hash / digest
854 CONFIG_CMD_I2C * I2C serial bus support
855 CONFIG_CMD_IDE * IDE harddisk support
856 CONFIG_CMD_IMI iminfo
857 CONFIG_CMD_IMLS List all images found in NOR flash
858 CONFIG_CMD_IMLS_NAND * List all images found in NAND flash
859 CONFIG_CMD_IMMAP * IMMR dump support
860 CONFIG_CMD_IOTRACE * I/O tracing for debugging
861 CONFIG_CMD_IMPORTENV * import an environment
862 CONFIG_CMD_INI * import data from an ini file into the env
863 CONFIG_CMD_IRQ * irqinfo
864 CONFIG_CMD_ITEST Integer/string test of 2 values
865 CONFIG_CMD_JFFS2 * JFFS2 Support
866 CONFIG_CMD_KGDB * kgdb
867 CONFIG_CMD_LDRINFO * ldrinfo (display Blackfin loader)
868 CONFIG_CMD_LINK_LOCAL * link-local IP address auto-configuration
870 CONFIG_CMD_LOADB loadb
871 CONFIG_CMD_LOADS loads
872 CONFIG_CMD_MD5SUM * print md5 message digest
873 (requires CONFIG_CMD_MEMORY and CONFIG_MD5)
874 CONFIG_CMD_MEMINFO * Display detailed memory information
875 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
877 CONFIG_CMD_MEMTEST * mtest
878 CONFIG_CMD_MISC Misc functions like sleep etc
879 CONFIG_CMD_MMC * MMC memory mapped support
880 CONFIG_CMD_MII * MII utility commands
881 CONFIG_CMD_MTDPARTS * MTD partition support
882 CONFIG_CMD_NAND * NAND support
883 CONFIG_CMD_NET bootp, tftpboot, rarpboot
884 CONFIG_CMD_NFS NFS support
885 CONFIG_CMD_PCA953X * PCA953x I2C gpio commands
886 CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command
887 CONFIG_CMD_PCI * pciinfo
888 CONFIG_CMD_PCMCIA * PCMCIA support
889 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
891 CONFIG_CMD_PORTIO * Port I/O
892 CONFIG_CMD_READ * Read raw data from partition
893 CONFIG_CMD_REGINFO * Register dump
894 CONFIG_CMD_RUN run command in env variable
895 CONFIG_CMD_SANDBOX * sb command to access sandbox features
896 CONFIG_CMD_SAVES * save S record dump
897 CONFIG_SCSI * SCSI Support
898 CONFIG_CMD_SDRAM * print SDRAM configuration information
899 (requires CONFIG_CMD_I2C)
900 CONFIG_CMD_SETGETDCR Support for DCR Register access
902 CONFIG_CMD_SF * Read/write/erase SPI NOR flash
903 CONFIG_CMD_SHA1SUM * print sha1 memory digest
904 (requires CONFIG_CMD_MEMORY)
905 CONFIG_CMD_SOFTSWITCH * Soft switch setting command for BF60x
906 CONFIG_CMD_SOURCE "source" command Support
907 CONFIG_CMD_SPI * SPI serial bus support
908 CONFIG_CMD_TFTPSRV * TFTP transfer in server mode
909 CONFIG_CMD_TFTPPUT * TFTP put command (upload)
910 CONFIG_CMD_TIME * run command and report execution time (ARM specific)
911 CONFIG_CMD_TIMER * access to the system tick timer
912 CONFIG_CMD_USB * USB support
913 CONFIG_CMD_CDP * Cisco Discover Protocol support
914 CONFIG_CMD_MFSL * Microblaze FSL support
915 CONFIG_CMD_XIMG Load part of Multi Image
916 CONFIG_CMD_UUID * Generate random UUID or GUID string
918 EXAMPLE: If you want all functions except of network
919 support you can write:
921 #include "config_cmd_all.h"
922 #undef CONFIG_CMD_NET
925 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
927 Note: Don't enable the "icache" and "dcache" commands
928 (configuration option CONFIG_CMD_CACHE) unless you know
929 what you (and your U-Boot users) are doing. Data
930 cache cannot be enabled on systems like the 8xx or
931 8260 (where accesses to the IMMR region must be
932 uncached), and it cannot be disabled on all other
933 systems where we (mis-) use the data cache to hold an
934 initial stack and some data.
937 XXX - this list needs to get updated!
939 - Removal of commands
940 If no commands are needed to boot, you can disable
941 CONFIG_CMDLINE to remove them. In this case, the command line
942 will not be available, and when U-Boot wants to execute the
943 boot command (on start-up) it will call board_run_command()
944 instead. This can reduce image size significantly for very
945 simple boot procedures.
947 - Regular expression support:
949 If this variable is defined, U-Boot is linked against
950 the SLRE (Super Light Regular Expression) library,
951 which adds regex support to some commands, as for
952 example "env grep" and "setexpr".
956 If this variable is defined, U-Boot will use a device tree
957 to configure its devices, instead of relying on statically
958 compiled #defines in the board file. This option is
959 experimental and only available on a few boards. The device
960 tree is available in the global data as gd->fdt_blob.
962 U-Boot needs to get its device tree from somewhere. This can
963 be done using one of the three options below:
966 If this variable is defined, U-Boot will embed a device tree
967 binary in its image. This device tree file should be in the
968 board directory and called <soc>-<board>.dts. The binary file
969 is then picked up in board_init_f() and made available through
970 the global data structure as gd->blob.
973 If this variable is defined, U-Boot will build a device tree
974 binary. It will be called u-boot.dtb. Architecture-specific
975 code will locate it at run-time. Generally this works by:
977 cat u-boot.bin u-boot.dtb >image.bin
979 and in fact, U-Boot does this for you, creating a file called
980 u-boot-dtb.bin which is useful in the common case. You can
981 still use the individual files if you need something more
985 If this variable is defined, U-Boot will use the device tree
986 provided by the board at runtime instead of embedding one with
987 the image. Only boards defining board_fdt_blob_setup() support
988 this option (see include/fdtdec.h file).
992 If this variable is defined, it enables watchdog
993 support for the SoC. There must be support in the SoC
994 specific code for a watchdog. For the 8xx and 8260
995 CPUs, the SIU Watchdog feature is enabled in the SYPCR
996 register. When supported for a specific SoC is
997 available, then no further board specific code should
1001 When using a watchdog circuitry external to the used
1002 SoC, then define this variable and provide board
1003 specific code for the "hw_watchdog_reset" function.
1005 CONFIG_AT91_HW_WDT_TIMEOUT
1006 specify the timeout in seconds. default 2 seconds.
1009 CONFIG_VERSION_VARIABLE
1010 If this variable is defined, an environment variable
1011 named "ver" is created by U-Boot showing the U-Boot
1012 version as printed by the "version" command.
1013 Any change to this variable will be reverted at the
1018 When CONFIG_CMD_DATE is selected, the type of the RTC
1019 has to be selected, too. Define exactly one of the
1022 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
1023 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
1024 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC
1025 CONFIG_RTC_MC146818 - use MC146818 RTC
1026 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
1027 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
1028 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
1029 CONFIG_RTC_DS1339 - use Maxim, Inc. DS1339 RTC
1030 CONFIG_RTC_DS164x - use Dallas DS164x RTC
1031 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
1032 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
1033 CONFIG_SYS_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
1034 CONFIG_SYS_RV3029_TCR - enable trickle charger on
1037 Note that if the RTC uses I2C, then the I2C interface
1038 must also be configured. See I2C Support, below.
1041 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
1043 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
1044 chip-ngpio pairs that tell the PCA953X driver the number of
1045 pins supported by a particular chip.
1047 Note that if the GPIO device uses I2C, then the I2C interface
1048 must also be configured. See I2C Support, below.
1051 When CONFIG_IO_TRACE is selected, U-Boot intercepts all I/O
1052 accesses and can checksum them or write a list of them out
1053 to memory. See the 'iotrace' command for details. This is
1054 useful for testing device drivers since it can confirm that
1055 the driver behaves the same way before and after a code
1056 change. Currently this is supported on sandbox and arm. To
1057 add support for your architecture, add '#include <iotrace.h>'
1058 to the bottom of arch/<arch>/include/asm/io.h and test.
1060 Example output from the 'iotrace stats' command is below.
1061 Note that if the trace buffer is exhausted, the checksum will
1062 still continue to operate.
1065 Start: 10000000 (buffer start address)
1066 Size: 00010000 (buffer size)
1067 Offset: 00000120 (current buffer offset)
1068 Output: 10000120 (start + offset)
1069 Count: 00000018 (number of trace records)
1070 CRC32: 9526fb66 (CRC32 of all trace records)
1072 - Timestamp Support:
1074 When CONFIG_TIMESTAMP is selected, the timestamp
1075 (date and time) of an image is printed by image
1076 commands like bootm or iminfo. This option is
1077 automatically enabled when you select CONFIG_CMD_DATE .
1079 - Partition Labels (disklabels) Supported:
1080 Zero or more of the following:
1081 CONFIG_MAC_PARTITION Apple's MacOS partition table.
1082 CONFIG_DOS_PARTITION MS Dos partition table, traditional on the
1083 Intel architecture, USB sticks, etc.
1084 CONFIG_ISO_PARTITION ISO partition table, used on CDROM etc.
1085 CONFIG_EFI_PARTITION GPT partition table, common when EFI is the
1086 bootloader. Note 2TB partition limit; see
1088 CONFIG_MTD_PARTITIONS Memory Technology Device partition table.
1090 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
1091 CONFIG_SCSI) you must configure support for at
1092 least one non-MTD partition type as well.
1095 CONFIG_IDE_RESET_ROUTINE - this is defined in several
1096 board configurations files but used nowhere!
1098 CONFIG_IDE_RESET - is this is defined, IDE Reset will
1099 be performed by calling the function
1100 ide_set_reset(int reset)
1101 which has to be defined in a board specific file
1106 Set this to enable ATAPI support.
1111 Set this to enable support for disks larger than 137GB
1112 Also look at CONFIG_SYS_64BIT_LBA.
1113 Whithout these , LBA48 support uses 32bit variables and will 'only'
1114 support disks up to 2.1TB.
1116 CONFIG_SYS_64BIT_LBA:
1117 When enabled, makes the IDE subsystem use 64bit sector addresses.
1121 At the moment only there is only support for the
1122 SYM53C8XX SCSI controller; define
1123 CONFIG_SCSI_SYM53C8XX to enable it.
1125 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
1126 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
1127 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
1128 maximum numbers of LUNs, SCSI ID's and target
1130 CONFIG_SYS_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
1132 The environment variable 'scsidevs' is set to the number of
1133 SCSI devices found during the last scan.
1135 - NETWORK Support (PCI):
1137 Support for Intel 8254x/8257x gigabit chips.
1140 Utility code for direct access to the SPI bus on Intel 8257x.
1141 This does not do anything useful unless you set at least one
1142 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
1144 CONFIG_E1000_SPI_GENERIC
1145 Allow generic access to the SPI bus on the Intel 8257x, for
1146 example with the "sspi" command.
1149 Management command for E1000 devices. When used on devices
1150 with SPI support you can reprogram the EEPROM from U-Boot.
1153 Support for Intel 82557/82559/82559ER chips.
1154 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
1155 write routine for first time initialisation.
1158 Support for Digital 2114x chips.
1159 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
1160 modem chip initialisation (KS8761/QS6611).
1163 Support for National dp83815 chips.
1166 Support for National dp8382[01] gigabit chips.
1168 - NETWORK Support (other):
1170 CONFIG_DRIVER_AT91EMAC
1171 Support for AT91RM9200 EMAC.
1174 Define this to use reduced MII inteface
1176 CONFIG_DRIVER_AT91EMAC_QUIET
1177 If this defined, the driver is quiet.
1178 The driver doen't show link status messages.
1180 CONFIG_CALXEDA_XGMAC
1181 Support for the Calxeda XGMAC device
1184 Support for SMSC's LAN91C96 chips.
1186 CONFIG_LAN91C96_USE_32_BIT
1187 Define this to enable 32 bit addressing
1190 Support for SMSC's LAN91C111 chip
1192 CONFIG_SMC91111_BASE
1193 Define this to hold the physical address
1194 of the device (I/O space)
1196 CONFIG_SMC_USE_32_BIT
1197 Define this if data bus is 32 bits
1199 CONFIG_SMC_USE_IOFUNCS
1200 Define this to use i/o functions instead of macros
1201 (some hardware wont work with macros)
1203 CONFIG_DRIVER_TI_EMAC
1204 Support for davinci emac
1206 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
1207 Define this if you have more then 3 PHYs.
1210 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
1212 CONFIG_FTGMAC100_EGIGA
1213 Define this to use GE link update with gigabit PHY.
1214 Define this if FTGMAC100 is connected to gigabit PHY.
1215 If your system has 10/100 PHY only, it might not occur
1216 wrong behavior. Because PHY usually return timeout or
1217 useless data when polling gigabit status and gigabit
1218 control registers. This behavior won't affect the
1219 correctnessof 10/100 link speed update.
1222 Support for SMSC's LAN911x and LAN921x chips
1225 Define this to hold the physical address
1226 of the device (I/O space)
1228 CONFIG_SMC911X_32_BIT
1229 Define this if data bus is 32 bits
1231 CONFIG_SMC911X_16_BIT
1232 Define this if data bus is 16 bits. If your processor
1233 automatically converts one 32 bit word to two 16 bit
1234 words you may also try CONFIG_SMC911X_32_BIT.
1237 Support for Renesas on-chip Ethernet controller
1239 CONFIG_SH_ETHER_USE_PORT
1240 Define the number of ports to be used
1242 CONFIG_SH_ETHER_PHY_ADDR
1243 Define the ETH PHY's address
1245 CONFIG_SH_ETHER_CACHE_WRITEBACK
1246 If this option is set, the driver enables cache flush.
1250 Support for PWM module on the imx6.
1254 Support TPM devices.
1256 CONFIG_TPM_TIS_INFINEON
1257 Support for Infineon i2c bus TPM devices. Only one device
1258 per system is supported at this time.
1260 CONFIG_TPM_TIS_I2C_BURST_LIMITATION
1261 Define the burst count bytes upper limit
1264 Support for STMicroelectronics TPM devices. Requires DM_TPM support.
1266 CONFIG_TPM_ST33ZP24_I2C
1267 Support for STMicroelectronics ST33ZP24 I2C devices.
1268 Requires TPM_ST33ZP24 and I2C.
1270 CONFIG_TPM_ST33ZP24_SPI
1271 Support for STMicroelectronics ST33ZP24 SPI devices.
1272 Requires TPM_ST33ZP24 and SPI.
1274 CONFIG_TPM_ATMEL_TWI
1275 Support for Atmel TWI TPM device. Requires I2C support.
1278 Support for generic parallel port TPM devices. Only one device
1279 per system is supported at this time.
1281 CONFIG_TPM_TIS_BASE_ADDRESS
1282 Base address where the generic TPM device is mapped
1283 to. Contemporary x86 systems usually map it at
1287 Add tpm monitor functions.
1288 Requires CONFIG_TPM. If CONFIG_TPM_AUTH_SESSIONS is set, also
1289 provides monitor access to authorized functions.
1292 Define this to enable the TPM support library which provides
1293 functional interfaces to some TPM commands.
1294 Requires support for a TPM device.
1296 CONFIG_TPM_AUTH_SESSIONS
1297 Define this to enable authorized functions in the TPM library.
1298 Requires CONFIG_TPM and CONFIG_SHA1.
1301 At the moment only the UHCI host controller is
1302 supported (PIP405, MIP405, MPC5200); define
1303 CONFIG_USB_UHCI to enable it.
1304 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
1305 and define CONFIG_USB_STORAGE to enable the USB
1308 Supported are USB Keyboards and USB Floppy drives
1310 MPC5200 USB requires additional defines:
1312 for 528 MHz Clock: 0x0001bbbb
1316 for differential drivers: 0x00001000
1317 for single ended drivers: 0x00005000
1318 for differential drivers on PSC3: 0x00000100
1319 for single ended drivers on PSC3: 0x00004100
1320 CONFIG_SYS_USB_EVENT_POLL
1321 May be defined to allow interrupt polling
1322 instead of using asynchronous interrupts
1324 CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
1325 txfilltuning field in the EHCI controller on reset.
1327 CONFIG_USB_DWC2_REG_ADDR the physical CPU address of the DWC2
1328 HW module registers.
1331 Define the below if you wish to use the USB console.
1332 Once firmware is rebuilt from a serial console issue the
1333 command "setenv stdin usbtty; setenv stdout usbtty" and
1334 attach your USB cable. The Unix command "dmesg" should print
1335 it has found a new device. The environment variable usbtty
1336 can be set to gserial or cdc_acm to enable your device to
1337 appear to a USB host as a Linux gserial device or a
1338 Common Device Class Abstract Control Model serial device.
1339 If you select usbtty = gserial you should be able to enumerate
1341 # modprobe usbserial vendor=0xVendorID product=0xProductID
1342 else if using cdc_acm, simply setting the environment
1343 variable usbtty to be cdc_acm should suffice. The following
1344 might be defined in YourBoardName.h
1347 Define this to build a UDC device
1350 Define this to have a tty type of device available to
1351 talk to the UDC device
1354 Define this to enable the high speed support for usb
1355 device and usbtty. If this feature is enabled, a routine
1356 int is_usbd_high_speed(void)
1357 also needs to be defined by the driver to dynamically poll
1358 whether the enumeration has succeded at high speed or full
1361 CONFIG_SYS_CONSOLE_IS_IN_ENV
1362 Define this if you want stdin, stdout &/or stderr to
1366 CONFIG_SYS_USB_EXTC_CLK 0xBLAH
1367 Derive USB clock from external clock "blah"
1368 - CONFIG_SYS_USB_EXTC_CLK 0x02
1370 If you have a USB-IF assigned VendorID then you may wish to
1371 define your own vendor specific values either in BoardName.h
1372 or directly in usbd_vendor_info.h. If you don't define
1373 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
1374 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
1375 should pretend to be a Linux device to it's target host.
1377 CONFIG_USBD_MANUFACTURER
1378 Define this string as the name of your company for
1379 - CONFIG_USBD_MANUFACTURER "my company"
1381 CONFIG_USBD_PRODUCT_NAME
1382 Define this string as the name of your product
1383 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
1385 CONFIG_USBD_VENDORID
1386 Define this as your assigned Vendor ID from the USB
1387 Implementors Forum. This *must* be a genuine Vendor ID
1388 to avoid polluting the USB namespace.
1389 - CONFIG_USBD_VENDORID 0xFFFF
1391 CONFIG_USBD_PRODUCTID
1392 Define this as the unique Product ID
1394 - CONFIG_USBD_PRODUCTID 0xFFFF
1396 - ULPI Layer Support:
1397 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
1398 the generic ULPI layer. The generic layer accesses the ULPI PHY
1399 via the platform viewport, so you need both the genric layer and
1400 the viewport enabled. Currently only Chipidea/ARC based
1401 viewport is supported.
1402 To enable the ULPI layer support, define CONFIG_USB_ULPI and
1403 CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
1404 If your ULPI phy needs a different reference clock than the
1405 standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to
1406 the appropriate value in Hz.
1409 The MMC controller on the Intel PXA is supported. To
1410 enable this define CONFIG_MMC. The MMC can be
1411 accessed from the boot prompt by mapping the device
1412 to physical memory similar to flash. Command line is
1413 enabled with CONFIG_CMD_MMC. The MMC driver also works with
1414 the FAT fs. This is enabled with CONFIG_CMD_FAT.
1417 Support for Renesas on-chip MMCIF controller
1419 CONFIG_SH_MMCIF_ADDR
1420 Define the base address of MMCIF registers
1423 Define the clock frequency for MMCIF
1425 CONFIG_SUPPORT_EMMC_BOOT
1426 Enable some additional features of the eMMC boot partitions.
1428 CONFIG_SUPPORT_EMMC_RPMB
1429 Enable the commands for reading, writing and programming the
1430 key for the Replay Protection Memory Block partition in eMMC.
1432 - USB Device Firmware Update (DFU) class support:
1433 CONFIG_USB_FUNCTION_DFU
1434 This enables the USB portion of the DFU USB class
1437 This enables the command "dfu" which is used to have
1438 U-Boot create a DFU class device via USB. This command
1439 requires that the "dfu_alt_info" environment variable be
1440 set and define the alt settings to expose to the host.
1443 This enables support for exposing (e)MMC devices via DFU.
1446 This enables support for exposing NAND devices via DFU.
1449 This enables support for exposing RAM via DFU.
1450 Note: DFU spec refer to non-volatile memory usage, but
1451 allow usages beyond the scope of spec - here RAM usage,
1452 one that would help mostly the developer.
1454 CONFIG_SYS_DFU_DATA_BUF_SIZE
1455 Dfu transfer uses a buffer before writing data to the
1456 raw storage device. Make the size (in bytes) of this buffer
1457 configurable. The size of this buffer is also configurable
1458 through the "dfu_bufsiz" environment variable.
1460 CONFIG_SYS_DFU_MAX_FILE_SIZE
1461 When updating files rather than the raw storage device,
1462 we use a static buffer to copy the file into and then write
1463 the buffer once we've been given the whole file. Define
1464 this to the maximum filesize (in bytes) for the buffer.
1465 Default is 4 MiB if undefined.
1467 DFU_DEFAULT_POLL_TIMEOUT
1468 Poll timeout [ms], is the timeout a device can send to the
1469 host. The host must wait for this timeout before sending
1470 a subsequent DFU_GET_STATUS request to the device.
1472 DFU_MANIFEST_POLL_TIMEOUT
1473 Poll timeout [ms], which the device sends to the host when
1474 entering dfuMANIFEST state. Host waits this timeout, before
1475 sending again an USB request to the device.
1477 - USB Device Android Fastboot support:
1478 CONFIG_USB_FUNCTION_FASTBOOT
1479 This enables the USB part of the fastboot gadget
1482 This enables the command "fastboot" which enables the Android
1483 fastboot mode for the platform's USB device. Fastboot is a USB
1484 protocol for downloading images, flashing and device control
1485 used on Android devices.
1486 See doc/README.android-fastboot for more information.
1488 CONFIG_ANDROID_BOOT_IMAGE
1489 This enables support for booting images which use the Android
1490 image format header.
1492 CONFIG_FASTBOOT_BUF_ADDR
1493 The fastboot protocol requires a large memory buffer for
1494 downloads. Define this to the starting RAM address to use for
1497 CONFIG_FASTBOOT_BUF_SIZE
1498 The fastboot protocol requires a large memory buffer for
1499 downloads. This buffer should be as large as possible for a
1500 platform. Define this to the size available RAM for fastboot.
1502 CONFIG_FASTBOOT_FLASH
1503 The fastboot protocol includes a "flash" command for writing
1504 the downloaded image to a non-volatile storage device. Define
1505 this to enable the "fastboot flash" command.
1507 CONFIG_FASTBOOT_FLASH_MMC_DEV
1508 The fastboot "flash" command requires additional information
1509 regarding the non-volatile storage device. Define this to
1510 the eMMC device that fastboot should use to store the image.
1512 CONFIG_FASTBOOT_GPT_NAME
1513 The fastboot "flash" command supports writing the downloaded
1514 image to the Protective MBR and the Primary GUID Partition
1515 Table. (Additionally, this downloaded image is post-processed
1516 to generate and write the Backup GUID Partition Table.)
1517 This occurs when the specified "partition name" on the
1518 "fastboot flash" command line matches this value.
1519 The default is "gpt" if undefined.
1521 CONFIG_FASTBOOT_MBR_NAME
1522 The fastboot "flash" command supports writing the downloaded
1524 This occurs when the "partition name" specified on the
1525 "fastboot flash" command line matches this value.
1526 If not defined the default value "mbr" is used.
1528 - Journaling Flash filesystem support:
1530 Define these for a default partition on a NAND device
1532 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1533 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1534 Define these for a default partition on a NOR device
1536 - FAT(File Allocation Table) filesystem write function support:
1539 Define this to enable support for saving memory data as a
1540 file in FAT formatted partition.
1542 This will also enable the command "fatwrite" enabling the
1543 user to write files to FAT.
1545 - FAT(File Allocation Table) filesystem cluster size:
1546 CONFIG_FS_FAT_MAX_CLUSTSIZE
1548 Define the max cluster size for fat operations else
1549 a default value of 65536 will be defined.
1552 See Kconfig help for available keyboard drivers.
1556 Define this to enable a custom keyboard support.
1557 This simply calls drv_keyboard_init() which must be
1558 defined in your board-specific files. This option is deprecated
1559 and is only used by novena. For new boards, use driver model
1564 Enable the Freescale DIU video driver. Reference boards for
1565 SOCs that have a DIU should define this macro to enable DIU
1566 support, and should also define these other macros:
1571 CONFIG_VIDEO_SW_CURSOR
1572 CONFIG_VGA_AS_SINGLE_DEVICE
1574 CONFIG_VIDEO_BMP_LOGO
1576 The DIU driver will look for the 'video-mode' environment
1577 variable, and if defined, enable the DIU as a console during
1578 boot. See the documentation file doc/README.video for a
1579 description of this variable.
1581 - LCD Support: CONFIG_LCD
1583 Define this to enable LCD support (for output to LCD
1584 display); also select one of the supported displays
1585 by defining one of these:
1589 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1591 CONFIG_NEC_NL6448AC33:
1593 NEC NL6448AC33-18. Active, color, single scan.
1595 CONFIG_NEC_NL6448BC20
1597 NEC NL6448BC20-08. 6.5", 640x480.
1598 Active, color, single scan.
1600 CONFIG_NEC_NL6448BC33_54
1602 NEC NL6448BC33-54. 10.4", 640x480.
1603 Active, color, single scan.
1607 Sharp 320x240. Active, color, single scan.
1608 It isn't 16x9, and I am not sure what it is.
1610 CONFIG_SHARP_LQ64D341
1612 Sharp LQ64D341 display, 640x480.
1613 Active, color, single scan.
1617 HLD1045 display, 640x480.
1618 Active, color, single scan.
1622 Optrex CBL50840-2 NF-FW 99 22 M5
1624 Hitachi LMG6912RPFC-00T
1628 320x240. Black & white.
1630 CONFIG_LCD_ALIGNMENT
1632 Normally the LCD is page-aligned (typically 4KB). If this is
1633 defined then the LCD will be aligned to this value instead.
1634 For ARM it is sometimes useful to use MMU_SECTION_SIZE
1635 here, since it is cheaper to change data cache settings on
1636 a per-section basis.
1641 Sometimes, for example if the display is mounted in portrait
1642 mode or even if it's mounted landscape but rotated by 180degree,
1643 we need to rotate our content of the display relative to the
1644 framebuffer, so that user can read the messages which are
1646 Once CONFIG_LCD_ROTATION is defined, the lcd_console will be
1647 initialized with a given rotation from "vl_rot" out of
1648 "vidinfo_t" which is provided by the board specific code.
1649 The value for vl_rot is coded as following (matching to
1650 fbcon=rotate:<n> linux-kernel commandline):
1651 0 = no rotation respectively 0 degree
1652 1 = 90 degree rotation
1653 2 = 180 degree rotation
1654 3 = 270 degree rotation
1656 If CONFIG_LCD_ROTATION is not defined, the console will be
1657 initialized with 0degree rotation.
1661 Support drawing of RLE8-compressed bitmaps on the LCD.
1665 Enables an 'i2c edid' command which can read EDID
1666 information over I2C from an attached LCD display.
1668 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1670 If this option is set, the environment is checked for
1671 a variable "splashimage". If found, the usual display
1672 of logo, copyright and system information on the LCD
1673 is suppressed and the BMP image at the address
1674 specified in "splashimage" is loaded instead. The
1675 console is redirected to the "nulldev", too. This
1676 allows for a "silent" boot where a splash screen is
1677 loaded very quickly after power-on.
1679 CONFIG_SPLASHIMAGE_GUARD
1681 If this option is set, then U-Boot will prevent the environment
1682 variable "splashimage" from being set to a problematic address
1683 (see doc/README.displaying-bmps).
1684 This option is useful for targets where, due to alignment
1685 restrictions, an improperly aligned BMP image will cause a data
1686 abort. If you think you will not have problems with unaligned
1687 accesses (for example because your toolchain prevents them)
1688 there is no need to set this option.
1690 CONFIG_SPLASH_SCREEN_ALIGN
1692 If this option is set the splash image can be freely positioned
1693 on the screen. Environment variable "splashpos" specifies the
1694 position as "x,y". If a positive number is given it is used as
1695 number of pixel from left/top. If a negative number is given it
1696 is used as number of pixel from right/bottom. You can also
1697 specify 'm' for centering the image.
1700 setenv splashpos m,m
1701 => image at center of screen
1703 setenv splashpos 30,20
1704 => image at x = 30 and y = 20
1706 setenv splashpos -10,m
1707 => vertically centered image
1708 at x = dspWidth - bmpWidth - 9
1710 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1712 If this option is set, additionally to standard BMP
1713 images, gzipped BMP images can be displayed via the
1714 splashscreen support or the bmp command.
1716 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1718 If this option is set, 8-bit RLE compressed BMP images
1719 can be displayed via the splashscreen support or the
1722 - Compression support:
1725 Enabled by default to support gzip compressed images.
1729 If this option is set, support for bzip2 compressed
1730 images is included. If not, only uncompressed and gzip
1731 compressed images are supported.
1733 NOTE: the bzip2 algorithm requires a lot of RAM, so
1734 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1739 If this option is set, support for lzma compressed
1742 Note: The LZMA algorithm adds between 2 and 4KB of code and it
1743 requires an amount of dynamic memory that is given by the
1746 (1846 + 768 << (lc + lp)) * sizeof(uint16)
1748 Where lc and lp stand for, respectively, Literal context bits
1749 and Literal pos bits.
1751 This value is upper-bounded by 14MB in the worst case. Anyway,
1752 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
1753 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
1754 a very small buffer.
1756 Use the lzmainfo tool to determinate the lc and lp values and
1757 then calculate the amount of needed dynamic memory (ensuring
1758 the appropriate CONFIG_SYS_MALLOC_LEN value).
1762 If this option is set, support for LZO compressed images
1768 The address of PHY on MII bus.
1770 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1772 The clock frequency of the MII bus
1776 If this option is set, support for speed/duplex
1777 detection of gigabit PHY is included.
1779 CONFIG_PHY_RESET_DELAY
1781 Some PHY like Intel LXT971A need extra delay after
1782 reset before any MII register access is possible.
1783 For such PHY, set this option to the usec delay
1784 required. (minimum 300usec for LXT971A)
1786 CONFIG_PHY_CMD_DELAY (ppc4xx)
1788 Some PHY like Intel LXT971A need extra delay after
1789 command issued before MII status register can be read
1794 Define a default value for the IP address to use for
1795 the default Ethernet interface, in case this is not
1796 determined through e.g. bootp.
1797 (Environment variable "ipaddr")
1799 - Server IP address:
1802 Defines a default value for the IP address of a TFTP
1803 server to contact when using the "tftboot" command.
1804 (Environment variable "serverip")
1806 CONFIG_KEEP_SERVERADDR
1808 Keeps the server's MAC address, in the env 'serveraddr'
1809 for passing to bootargs (like Linux's netconsole option)
1811 - Gateway IP address:
1814 Defines a default value for the IP address of the
1815 default router where packets to other networks are
1817 (Environment variable "gatewayip")
1822 Defines a default value for the subnet mask (or
1823 routing prefix) which is used to determine if an IP
1824 address belongs to the local subnet or needs to be
1825 forwarded through a router.
1826 (Environment variable "netmask")
1828 - Multicast TFTP Mode:
1831 Defines whether you want to support multicast TFTP as per
1832 rfc-2090; for example to work with atftp. Lets lots of targets
1833 tftp down the same boot image concurrently. Note: the Ethernet
1834 driver in use must provide a function: mcast() to join/leave a
1837 - BOOTP Recovery Mode:
1838 CONFIG_BOOTP_RANDOM_DELAY
1840 If you have many targets in a network that try to
1841 boot using BOOTP, you may want to avoid that all
1842 systems send out BOOTP requests at precisely the same
1843 moment (which would happen for instance at recovery
1844 from a power failure, when all systems will try to
1845 boot, thus flooding the BOOTP server. Defining
1846 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1847 inserted before sending out BOOTP requests. The
1848 following delays are inserted then:
1850 1st BOOTP request: delay 0 ... 1 sec
1851 2nd BOOTP request: delay 0 ... 2 sec
1852 3rd BOOTP request: delay 0 ... 4 sec
1854 BOOTP requests: delay 0 ... 8 sec
1856 CONFIG_BOOTP_ID_CACHE_SIZE
1858 BOOTP packets are uniquely identified using a 32-bit ID. The
1859 server will copy the ID from client requests to responses and
1860 U-Boot will use this to determine if it is the destination of
1861 an incoming response. Some servers will check that addresses
1862 aren't in use before handing them out (usually using an ARP
1863 ping) and therefore take up to a few hundred milliseconds to
1864 respond. Network congestion may also influence the time it
1865 takes for a response to make it back to the client. If that
1866 time is too long, U-Boot will retransmit requests. In order
1867 to allow earlier responses to still be accepted after these
1868 retransmissions, U-Boot's BOOTP client keeps a small cache of
1869 IDs. The CONFIG_BOOTP_ID_CACHE_SIZE controls the size of this
1870 cache. The default is to keep IDs for up to four outstanding
1871 requests. Increasing this will allow U-Boot to accept offers
1872 from a BOOTP client in networks with unusually high latency.
1874 - DHCP Advanced Options:
1875 You can fine tune the DHCP functionality by defining
1876 CONFIG_BOOTP_* symbols:
1878 CONFIG_BOOTP_SUBNETMASK
1879 CONFIG_BOOTP_GATEWAY
1880 CONFIG_BOOTP_HOSTNAME
1881 CONFIG_BOOTP_NISDOMAIN
1882 CONFIG_BOOTP_BOOTPATH
1883 CONFIG_BOOTP_BOOTFILESIZE
1886 CONFIG_BOOTP_SEND_HOSTNAME
1887 CONFIG_BOOTP_NTPSERVER
1888 CONFIG_BOOTP_TIMEOFFSET
1889 CONFIG_BOOTP_VENDOREX
1890 CONFIG_BOOTP_MAY_FAIL
1892 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1893 environment variable, not the BOOTP server.
1895 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
1896 after the configured retry count, the call will fail
1897 instead of starting over. This can be used to fail over
1898 to Link-local IP address configuration if the DHCP server
1901 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1902 serverip from a DHCP server, it is possible that more
1903 than one DNS serverip is offered to the client.
1904 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1905 serverip will be stored in the additional environment
1906 variable "dnsip2". The first DNS serverip is always
1907 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1910 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1911 to do a dynamic update of a DNS server. To do this, they
1912 need the hostname of the DHCP requester.
1913 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1914 of the "hostname" environment variable is passed as
1915 option 12 to the DHCP server.
1917 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1919 A 32bit value in microseconds for a delay between
1920 receiving a "DHCP Offer" and sending the "DHCP Request".
1921 This fixes a problem with certain DHCP servers that don't
1922 respond 100% of the time to a "DHCP request". E.g. On an
1923 AT91RM9200 processor running at 180MHz, this delay needed
1924 to be *at least* 15,000 usec before a Windows Server 2003
1925 DHCP server would reply 100% of the time. I recommend at
1926 least 50,000 usec to be safe. The alternative is to hope
1927 that one of the retries will be successful but note that
1928 the DHCP timeout and retry process takes a longer than
1931 - Link-local IP address negotiation:
1932 Negotiate with other link-local clients on the local network
1933 for an address that doesn't require explicit configuration.
1934 This is especially useful if a DHCP server cannot be guaranteed
1935 to exist in all environments that the device must operate.
1937 See doc/README.link-local for more information.
1940 CONFIG_CDP_DEVICE_ID
1942 The device id used in CDP trigger frames.
1944 CONFIG_CDP_DEVICE_ID_PREFIX
1946 A two character string which is prefixed to the MAC address
1951 A printf format string which contains the ascii name of
1952 the port. Normally is set to "eth%d" which sets
1953 eth0 for the first Ethernet, eth1 for the second etc.
1955 CONFIG_CDP_CAPABILITIES
1957 A 32bit integer which indicates the device capabilities;
1958 0x00000010 for a normal host which does not forwards.
1962 An ascii string containing the version of the software.
1966 An ascii string containing the name of the platform.
1970 A 32bit integer sent on the trigger.
1972 CONFIG_CDP_POWER_CONSUMPTION
1974 A 16bit integer containing the power consumption of the
1975 device in .1 of milliwatts.
1977 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1979 A byte containing the id of the VLAN.
1981 - Status LED: CONFIG_LED_STATUS
1983 Several configurations allow to display the current
1984 status using a LED. For instance, the LED will blink
1985 fast while running U-Boot code, stop blinking as
1986 soon as a reply to a BOOTP request was received, and
1987 start blinking slow once the Linux kernel is running
1988 (supported by a status LED driver in the Linux
1989 kernel). Defining CONFIG_LED_STATUS enables this
1994 CONFIG_LED_STATUS_GPIO
1995 The status LED can be connected to a GPIO pin.
1996 In such cases, the gpio_led driver can be used as a
1997 status LED backend implementation. Define CONFIG_LED_STATUS_GPIO
1998 to include the gpio_led driver in the U-Boot binary.
2000 CONFIG_GPIO_LED_INVERTED_TABLE
2001 Some GPIO connected LEDs may have inverted polarity in which
2002 case the GPIO high value corresponds to LED off state and
2003 GPIO low value corresponds to LED on state.
2004 In such cases CONFIG_GPIO_LED_INVERTED_TABLE may be defined
2005 with a list of GPIO LEDs that have inverted polarity.
2007 - CAN Support: CONFIG_CAN_DRIVER
2009 Defining CONFIG_CAN_DRIVER enables CAN driver support
2010 on those systems that support this (optional)
2011 feature, like the TQM8xxL modules.
2013 - I2C Support: CONFIG_SYS_I2C
2015 This enable the NEW i2c subsystem, and will allow you to use
2016 i2c commands at the u-boot command line (as long as you set
2017 CONFIG_CMD_I2C in CONFIG_COMMANDS) and communicate with i2c
2018 based realtime clock chips or other i2c devices. See
2019 common/cmd_i2c.c for a description of the command line
2022 ported i2c driver to the new framework:
2023 - drivers/i2c/soft_i2c.c:
2024 - activate first bus with CONFIG_SYS_I2C_SOFT define
2025 CONFIG_SYS_I2C_SOFT_SPEED and CONFIG_SYS_I2C_SOFT_SLAVE
2026 for defining speed and slave address
2027 - activate second bus with I2C_SOFT_DECLARATIONS2 define
2028 CONFIG_SYS_I2C_SOFT_SPEED_2 and CONFIG_SYS_I2C_SOFT_SLAVE_2
2029 for defining speed and slave address
2030 - activate third bus with I2C_SOFT_DECLARATIONS3 define
2031 CONFIG_SYS_I2C_SOFT_SPEED_3 and CONFIG_SYS_I2C_SOFT_SLAVE_3
2032 for defining speed and slave address
2033 - activate fourth bus with I2C_SOFT_DECLARATIONS4 define
2034 CONFIG_SYS_I2C_SOFT_SPEED_4 and CONFIG_SYS_I2C_SOFT_SLAVE_4
2035 for defining speed and slave address
2037 - drivers/i2c/fsl_i2c.c:
2038 - activate i2c driver with CONFIG_SYS_I2C_FSL
2039 define CONFIG_SYS_FSL_I2C_OFFSET for setting the register
2040 offset CONFIG_SYS_FSL_I2C_SPEED for the i2c speed and
2041 CONFIG_SYS_FSL_I2C_SLAVE for the slave addr of the first
2043 - If your board supports a second fsl i2c bus, define
2044 CONFIG_SYS_FSL_I2C2_OFFSET for the register offset
2045 CONFIG_SYS_FSL_I2C2_SPEED for the speed and
2046 CONFIG_SYS_FSL_I2C2_SLAVE for the slave address of the
2049 - drivers/i2c/tegra_i2c.c:
2050 - activate this driver with CONFIG_SYS_I2C_TEGRA
2051 - This driver adds 4 i2c buses with a fix speed from
2052 100000 and the slave addr 0!
2054 - drivers/i2c/ppc4xx_i2c.c
2055 - activate this driver with CONFIG_SYS_I2C_PPC4XX
2056 - CONFIG_SYS_I2C_PPC4XX_CH0 activate hardware channel 0
2057 - CONFIG_SYS_I2C_PPC4XX_CH1 activate hardware channel 1
2059 - drivers/i2c/i2c_mxc.c
2060 - activate this driver with CONFIG_SYS_I2C_MXC
2061 - enable bus 1 with CONFIG_SYS_I2C_MXC_I2C1
2062 - enable bus 2 with CONFIG_SYS_I2C_MXC_I2C2
2063 - enable bus 3 with CONFIG_SYS_I2C_MXC_I2C3
2064 - enable bus 4 with CONFIG_SYS_I2C_MXC_I2C4
2065 - define speed for bus 1 with CONFIG_SYS_MXC_I2C1_SPEED
2066 - define slave for bus 1 with CONFIG_SYS_MXC_I2C1_SLAVE
2067 - define speed for bus 2 with CONFIG_SYS_MXC_I2C2_SPEED
2068 - define slave for bus 2 with CONFIG_SYS_MXC_I2C2_SLAVE
2069 - define speed for bus 3 with CONFIG_SYS_MXC_I2C3_SPEED
2070 - define slave for bus 3 with CONFIG_SYS_MXC_I2C3_SLAVE
2071 - define speed for bus 4 with CONFIG_SYS_MXC_I2C4_SPEED
2072 - define slave for bus 4 with CONFIG_SYS_MXC_I2C4_SLAVE
2073 If those defines are not set, default value is 100000
2074 for speed, and 0 for slave.
2076 - drivers/i2c/rcar_i2c.c:
2077 - activate this driver with CONFIG_SYS_I2C_RCAR
2078 - This driver adds 4 i2c buses
2080 - CONFIG_SYS_RCAR_I2C0_BASE for setting the register channel 0
2081 - CONFIG_SYS_RCAR_I2C0_SPEED for for the speed channel 0
2082 - CONFIG_SYS_RCAR_I2C1_BASE for setting the register channel 1
2083 - CONFIG_SYS_RCAR_I2C1_SPEED for for the speed channel 1
2084 - CONFIG_SYS_RCAR_I2C2_BASE for setting the register channel 2
2085 - CONFIG_SYS_RCAR_I2C2_SPEED for for the speed channel 2
2086 - CONFIG_SYS_RCAR_I2C3_BASE for setting the register channel 3
2087 - CONFIG_SYS_RCAR_I2C3_SPEED for for the speed channel 3
2088 - CONFIF_SYS_RCAR_I2C_NUM_CONTROLLERS for number of i2c buses
2090 - drivers/i2c/sh_i2c.c:
2091 - activate this driver with CONFIG_SYS_I2C_SH
2092 - This driver adds from 2 to 5 i2c buses
2094 - CONFIG_SYS_I2C_SH_BASE0 for setting the register channel 0
2095 - CONFIG_SYS_I2C_SH_SPEED0 for for the speed channel 0
2096 - CONFIG_SYS_I2C_SH_BASE1 for setting the register channel 1
2097 - CONFIG_SYS_I2C_SH_SPEED1 for for the speed channel 1
2098 - CONFIG_SYS_I2C_SH_BASE2 for setting the register channel 2
2099 - CONFIG_SYS_I2C_SH_SPEED2 for for the speed channel 2
2100 - CONFIG_SYS_I2C_SH_BASE3 for setting the register channel 3
2101 - CONFIG_SYS_I2C_SH_SPEED3 for for the speed channel 3
2102 - CONFIG_SYS_I2C_SH_BASE4 for setting the register channel 4
2103 - CONFIG_SYS_I2C_SH_SPEED4 for for the speed channel 4
2104 - CONFIG_SYS_I2C_SH_NUM_CONTROLLERS for number of i2c buses
2106 - drivers/i2c/omap24xx_i2c.c
2107 - activate this driver with CONFIG_SYS_I2C_OMAP24XX
2108 - CONFIG_SYS_OMAP24_I2C_SPEED speed channel 0
2109 - CONFIG_SYS_OMAP24_I2C_SLAVE slave addr channel 0
2110 - CONFIG_SYS_OMAP24_I2C_SPEED1 speed channel 1
2111 - CONFIG_SYS_OMAP24_I2C_SLAVE1 slave addr channel 1
2112 - CONFIG_SYS_OMAP24_I2C_SPEED2 speed channel 2
2113 - CONFIG_SYS_OMAP24_I2C_SLAVE2 slave addr channel 2
2114 - CONFIG_SYS_OMAP24_I2C_SPEED3 speed channel 3
2115 - CONFIG_SYS_OMAP24_I2C_SLAVE3 slave addr channel 3
2116 - CONFIG_SYS_OMAP24_I2C_SPEED4 speed channel 4
2117 - CONFIG_SYS_OMAP24_I2C_SLAVE4 slave addr channel 4
2119 - drivers/i2c/zynq_i2c.c
2120 - activate this driver with CONFIG_SYS_I2C_ZYNQ
2121 - set CONFIG_SYS_I2C_ZYNQ_SPEED for speed setting
2122 - set CONFIG_SYS_I2C_ZYNQ_SLAVE for slave addr
2124 - drivers/i2c/s3c24x0_i2c.c:
2125 - activate this driver with CONFIG_SYS_I2C_S3C24X0
2126 - This driver adds i2c buses (11 for Exynos5250, Exynos5420
2127 9 i2c buses for Exynos4 and 1 for S3C24X0 SoCs from Samsung)
2128 with a fix speed from 100000 and the slave addr 0!
2130 - drivers/i2c/ihs_i2c.c
2131 - activate this driver with CONFIG_SYS_I2C_IHS
2132 - CONFIG_SYS_I2C_IHS_CH0 activate hardware channel 0
2133 - CONFIG_SYS_I2C_IHS_SPEED_0 speed channel 0
2134 - CONFIG_SYS_I2C_IHS_SLAVE_0 slave addr channel 0
2135 - CONFIG_SYS_I2C_IHS_CH1 activate hardware channel 1
2136 - CONFIG_SYS_I2C_IHS_SPEED_1 speed channel 1
2137 - CONFIG_SYS_I2C_IHS_SLAVE_1 slave addr channel 1
2138 - CONFIG_SYS_I2C_IHS_CH2 activate hardware channel 2
2139 - CONFIG_SYS_I2C_IHS_SPEED_2 speed channel 2
2140 - CONFIG_SYS_I2C_IHS_SLAVE_2 slave addr channel 2
2141 - CONFIG_SYS_I2C_IHS_CH3 activate hardware channel 3
2142 - CONFIG_SYS_I2C_IHS_SPEED_3 speed channel 3
2143 - CONFIG_SYS_I2C_IHS_SLAVE_3 slave addr channel 3
2144 - activate dual channel with CONFIG_SYS_I2C_IHS_DUAL
2145 - CONFIG_SYS_I2C_IHS_SPEED_0_1 speed channel 0_1
2146 - CONFIG_SYS_I2C_IHS_SLAVE_0_1 slave addr channel 0_1
2147 - CONFIG_SYS_I2C_IHS_SPEED_1_1 speed channel 1_1
2148 - CONFIG_SYS_I2C_IHS_SLAVE_1_1 slave addr channel 1_1
2149 - CONFIG_SYS_I2C_IHS_SPEED_2_1 speed channel 2_1
2150 - CONFIG_SYS_I2C_IHS_SLAVE_2_1 slave addr channel 2_1
2151 - CONFIG_SYS_I2C_IHS_SPEED_3_1 speed channel 3_1
2152 - CONFIG_SYS_I2C_IHS_SLAVE_3_1 slave addr channel 3_1
2156 CONFIG_SYS_NUM_I2C_BUSES
2157 Hold the number of i2c buses you want to use.
2159 CONFIG_SYS_I2C_DIRECT_BUS
2160 define this, if you don't use i2c muxes on your hardware.
2161 if CONFIG_SYS_I2C_MAX_HOPS is not defined or == 0 you can
2164 CONFIG_SYS_I2C_MAX_HOPS
2165 define how many muxes are maximal consecutively connected
2166 on one i2c bus. If you not use i2c muxes, omit this
2169 CONFIG_SYS_I2C_BUSES
2170 hold a list of buses you want to use, only used if
2171 CONFIG_SYS_I2C_DIRECT_BUS is not defined, for example
2172 a board with CONFIG_SYS_I2C_MAX_HOPS = 1 and
2173 CONFIG_SYS_NUM_I2C_BUSES = 9:
2175 CONFIG_SYS_I2C_BUSES {{0, {I2C_NULL_HOP}}, \
2176 {0, {{I2C_MUX_PCA9547, 0x70, 1}}}, \
2177 {0, {{I2C_MUX_PCA9547, 0x70, 2}}}, \
2178 {0, {{I2C_MUX_PCA9547, 0x70, 3}}}, \
2179 {0, {{I2C_MUX_PCA9547, 0x70, 4}}}, \
2180 {0, {{I2C_MUX_PCA9547, 0x70, 5}}}, \
2181 {1, {I2C_NULL_HOP}}, \
2182 {1, {{I2C_MUX_PCA9544, 0x72, 1}}}, \
2183 {1, {{I2C_MUX_PCA9544, 0x72, 2}}}, \
2187 bus 0 on adapter 0 without a mux
2188 bus 1 on adapter 0 with a PCA9547 on address 0x70 port 1
2189 bus 2 on adapter 0 with a PCA9547 on address 0x70 port 2
2190 bus 3 on adapter 0 with a PCA9547 on address 0x70 port 3
2191 bus 4 on adapter 0 with a PCA9547 on address 0x70 port 4
2192 bus 5 on adapter 0 with a PCA9547 on address 0x70 port 5
2193 bus 6 on adapter 1 without a mux
2194 bus 7 on adapter 1 with a PCA9544 on address 0x72 port 1
2195 bus 8 on adapter 1 with a PCA9544 on address 0x72 port 2
2197 If you do not have i2c muxes on your board, omit this define.
2199 - Legacy I2C Support:
2200 If you use the software i2c interface (CONFIG_SYS_I2C_SOFT)
2201 then the following macros need to be defined (examples are
2202 from include/configs/lwmon.h):
2206 (Optional). Any commands necessary to enable the I2C
2207 controller or configure ports.
2209 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
2213 (Only for MPC8260 CPU). The I/O port to use (the code
2214 assumes both bits are on the same port). Valid values
2215 are 0..3 for ports A..D.
2219 The code necessary to make the I2C data line active
2220 (driven). If the data line is open collector, this
2223 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
2227 The code necessary to make the I2C data line tri-stated
2228 (inactive). If the data line is open collector, this
2231 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
2235 Code that returns true if the I2C data line is high,
2238 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
2242 If <bit> is true, sets the I2C data line high. If it
2243 is false, it clears it (low).
2245 eg: #define I2C_SDA(bit) \
2246 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
2247 else immr->im_cpm.cp_pbdat &= ~PB_SDA
2251 If <bit> is true, sets the I2C clock line high. If it
2252 is false, it clears it (low).
2254 eg: #define I2C_SCL(bit) \
2255 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
2256 else immr->im_cpm.cp_pbdat &= ~PB_SCL
2260 This delay is invoked four times per clock cycle so this
2261 controls the rate of data transfer. The data rate thus
2262 is 1 / (I2C_DELAY * 4). Often defined to be something
2265 #define I2C_DELAY udelay(2)
2267 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
2269 If your arch supports the generic GPIO framework (asm/gpio.h),
2270 then you may alternatively define the two GPIOs that are to be
2271 used as SCL / SDA. Any of the previous I2C_xxx macros will
2272 have GPIO-based defaults assigned to them as appropriate.
2274 You should define these to the GPIO value as given directly to
2275 the generic GPIO functions.
2277 CONFIG_SYS_I2C_INIT_BOARD
2279 When a board is reset during an i2c bus transfer
2280 chips might think that the current transfer is still
2281 in progress. On some boards it is possible to access
2282 the i2c SCLK line directly, either by using the
2283 processor pin as a GPIO or by having a second pin
2284 connected to the bus. If this option is defined a
2285 custom i2c_init_board() routine in boards/xxx/board.c
2286 is run early in the boot sequence.
2288 CONFIG_I2C_MULTI_BUS
2290 This option allows the use of multiple I2C buses, each of which
2291 must have a controller. At any point in time, only one bus is
2292 active. To switch to a different bus, use the 'i2c dev' command.
2293 Note that bus numbering is zero-based.
2295 CONFIG_SYS_I2C_NOPROBES
2297 This option specifies a list of I2C devices that will be skipped
2298 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
2299 is set, specify a list of bus-device pairs. Otherwise, specify
2300 a 1D array of device addresses
2303 #undef CONFIG_I2C_MULTI_BUS
2304 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
2306 will skip addresses 0x50 and 0x68 on a board with one I2C bus
2308 #define CONFIG_I2C_MULTI_BUS
2309 #define CONFIG_SYS_I2C_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
2311 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
2313 CONFIG_SYS_SPD_BUS_NUM
2315 If defined, then this indicates the I2C bus number for DDR SPD.
2316 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
2318 CONFIG_SYS_RTC_BUS_NUM
2320 If defined, then this indicates the I2C bus number for the RTC.
2321 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
2323 CONFIG_SOFT_I2C_READ_REPEATED_START
2325 defining this will force the i2c_read() function in
2326 the soft_i2c driver to perform an I2C repeated start
2327 between writing the address pointer and reading the
2328 data. If this define is omitted the default behaviour
2329 of doing a stop-start sequence will be used. Most I2C
2330 devices can use either method, but some require one or
2333 - SPI Support: CONFIG_SPI
2335 Enables SPI driver (so far only tested with
2336 SPI EEPROM, also an instance works with Crystal A/D and
2337 D/As on the SACSng board)
2341 Enables the driver for SPI controller on SuperH. Currently
2342 only SH7757 is supported.
2346 Enables a software (bit-bang) SPI driver rather than
2347 using hardware support. This is a general purpose
2348 driver that only requires three general I/O port pins
2349 (two outputs, one input) to function. If this is
2350 defined, the board configuration must define several
2351 SPI configuration items (port pins to use, etc). For
2352 an example, see include/configs/sacsng.h.
2356 Enables a hardware SPI driver for general-purpose reads
2357 and writes. As with CONFIG_SOFT_SPI, the board configuration
2358 must define a list of chip-select function pointers.
2359 Currently supported on some MPC8xxx processors. For an
2360 example, see include/configs/mpc8349emds.h.
2364 Enables the driver for the SPI controllers on i.MX and MXC
2365 SoCs. Currently i.MX31/35/51 are supported.
2367 CONFIG_SYS_SPI_MXC_WAIT
2368 Timeout for waiting until spi transfer completed.
2369 default: (CONFIG_SYS_HZ/100) /* 10 ms */
2371 - FPGA Support: CONFIG_FPGA
2373 Enables FPGA subsystem.
2375 CONFIG_FPGA_<vendor>
2377 Enables support for specific chip vendors.
2380 CONFIG_FPGA_<family>
2382 Enables support for FPGA family.
2383 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
2387 Specify the number of FPGA devices to support.
2389 CONFIG_CMD_FPGA_LOADMK
2391 Enable support for fpga loadmk command
2393 CONFIG_CMD_FPGA_LOADP
2395 Enable support for fpga loadp command - load partial bitstream
2397 CONFIG_CMD_FPGA_LOADBP
2399 Enable support for fpga loadbp command - load partial bitstream
2402 CONFIG_SYS_FPGA_PROG_FEEDBACK
2404 Enable printing of hash marks during FPGA configuration.
2406 CONFIG_SYS_FPGA_CHECK_BUSY
2408 Enable checks on FPGA configuration interface busy
2409 status by the configuration function. This option
2410 will require a board or device specific function to
2415 If defined, a function that provides delays in the FPGA
2416 configuration driver.
2418 CONFIG_SYS_FPGA_CHECK_CTRLC
2419 Allow Control-C to interrupt FPGA configuration
2421 CONFIG_SYS_FPGA_CHECK_ERROR
2423 Check for configuration errors during FPGA bitfile
2424 loading. For example, abort during Virtex II
2425 configuration if the INIT_B line goes low (which
2426 indicated a CRC error).
2428 CONFIG_SYS_FPGA_WAIT_INIT
2430 Maximum time to wait for the INIT_B line to de-assert
2431 after PROB_B has been de-asserted during a Virtex II
2432 FPGA configuration sequence. The default time is 500
2435 CONFIG_SYS_FPGA_WAIT_BUSY
2437 Maximum time to wait for BUSY to de-assert during
2438 Virtex II FPGA configuration. The default is 5 ms.
2440 CONFIG_SYS_FPGA_WAIT_CONFIG
2442 Time to wait after FPGA configuration. The default is
2445 - Configuration Management:
2448 Some SoCs need special image types (e.g. U-Boot binary
2449 with a special header) as build targets. By defining
2450 CONFIG_BUILD_TARGET in the SoC / board header, this
2451 special image will be automatically built upon calling
2456 If defined, this string will be added to the U-Boot
2457 version information (U_BOOT_VERSION)
2459 - Vendor Parameter Protection:
2461 U-Boot considers the values of the environment
2462 variables "serial#" (Board Serial Number) and
2463 "ethaddr" (Ethernet Address) to be parameters that
2464 are set once by the board vendor / manufacturer, and
2465 protects these variables from casual modification by
2466 the user. Once set, these variables are read-only,
2467 and write or delete attempts are rejected. You can
2468 change this behaviour:
2470 If CONFIG_ENV_OVERWRITE is #defined in your config
2471 file, the write protection for vendor parameters is
2472 completely disabled. Anybody can change or delete
2475 Alternatively, if you define _both_ an ethaddr in the
2476 default env _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2477 Ethernet address is installed in the environment,
2478 which can be changed exactly ONCE by the user. [The
2479 serial# is unaffected by this, i. e. it remains
2482 The same can be accomplished in a more flexible way
2483 for any variable by configuring the type of access
2484 to allow for those variables in the ".flags" variable
2485 or define CONFIG_ENV_FLAGS_LIST_STATIC.
2490 Define this variable to enable the reservation of
2491 "protected RAM", i. e. RAM which is not overwritten
2492 by U-Boot. Define CONFIG_PRAM to hold the number of
2493 kB you want to reserve for pRAM. You can overwrite
2494 this default value by defining an environment
2495 variable "pram" to the number of kB you want to
2496 reserve. Note that the board info structure will
2497 still show the full amount of RAM. If pRAM is
2498 reserved, a new environment variable "mem" will
2499 automatically be defined to hold the amount of
2500 remaining RAM in a form that can be passed as boot
2501 argument to Linux, for instance like that:
2503 setenv bootargs ... mem=\${mem}
2506 This way you can tell Linux not to use this memory,
2507 either, which results in a memory region that will
2508 not be affected by reboots.
2510 *WARNING* If your board configuration uses automatic
2511 detection of the RAM size, you must make sure that
2512 this memory test is non-destructive. So far, the
2513 following board configurations are known to be
2516 IVMS8, IVML24, SPD8xx, TQM8xxL,
2517 HERMES, IP860, RPXlite, LWMON,
2520 - Access to physical memory region (> 4GB)
2521 Some basic support is provided for operations on memory not
2522 normally accessible to U-Boot - e.g. some architectures
2523 support access to more than 4GB of memory on 32-bit
2524 machines using physical address extension or similar.
2525 Define CONFIG_PHYSMEM to access this basic support, which
2526 currently only supports clearing the memory.
2531 Define this variable to stop the system in case of a
2532 fatal error, so that you have to reset it manually.
2533 This is probably NOT a good idea for an embedded
2534 system where you want the system to reboot
2535 automatically as fast as possible, but it may be
2536 useful during development since you can try to debug
2537 the conditions that lead to the situation.
2539 CONFIG_NET_RETRY_COUNT
2541 This variable defines the number of retries for
2542 network operations like ARP, RARP, TFTP, or BOOTP
2543 before giving up the operation. If not defined, a
2544 default value of 5 is used.
2548 Timeout waiting for an ARP reply in milliseconds.
2552 Timeout in milliseconds used in NFS protocol.
2553 If you encounter "ERROR: Cannot umount" in nfs command,
2554 try longer timeout such as
2555 #define CONFIG_NFS_TIMEOUT 10000UL
2557 - Command Interpreter:
2558 CONFIG_AUTO_COMPLETE
2560 Enable auto completion of commands using TAB.
2562 CONFIG_SYS_PROMPT_HUSH_PS2
2564 This defines the secondary prompt string, which is
2565 printed when the command interpreter needs more input
2566 to complete a command. Usually "> ".
2570 In the current implementation, the local variables
2571 space and global environment variables space are
2572 separated. Local variables are those you define by
2573 simply typing `name=value'. To access a local
2574 variable later on, you have write `$name' or
2575 `${name}'; to execute the contents of a variable
2576 directly type `$name' at the command prompt.
2578 Global environment variables are those you use
2579 setenv/printenv to work with. To run a command stored
2580 in such a variable, you need to use the run command,
2581 and you must not use the '$' sign to access them.
2583 To store commands and special characters in a
2584 variable, please use double quotation marks
2585 surrounding the whole text of the variable, instead
2586 of the backslashes before semicolons and special
2589 - Command Line Editing and History:
2590 CONFIG_CMDLINE_EDITING
2592 Enable editing and History functions for interactive
2593 command line input operations
2595 - Command Line PS1/PS2 support:
2596 CONFIG_CMDLINE_PS_SUPPORT
2598 Enable support for changing the command prompt string
2599 at run-time. Only static string is supported so far.
2600 The string is obtained from environment variables PS1
2603 - Default Environment:
2604 CONFIG_EXTRA_ENV_SETTINGS
2606 Define this to contain any number of null terminated
2607 strings (variable = value pairs) that will be part of
2608 the default environment compiled into the boot image.
2610 For example, place something like this in your
2611 board's config file:
2613 #define CONFIG_EXTRA_ENV_SETTINGS \
2617 Warning: This method is based on knowledge about the
2618 internal format how the environment is stored by the
2619 U-Boot code. This is NOT an official, exported
2620 interface! Although it is unlikely that this format
2621 will change soon, there is no guarantee either.
2622 You better know what you are doing here.
2624 Note: overly (ab)use of the default environment is
2625 discouraged. Make sure to check other ways to preset
2626 the environment like the "source" command or the
2629 CONFIG_ENV_VARS_UBOOT_CONFIG
2631 Define this in order to add variables describing the
2632 U-Boot build configuration to the default environment.
2633 These will be named arch, cpu, board, vendor, and soc.
2635 Enabling this option will cause the following to be defined:
2643 CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG
2645 Define this in order to add variables describing certain
2646 run-time determined information about the hardware to the
2647 environment. These will be named board_name, board_rev.
2649 CONFIG_DELAY_ENVIRONMENT
2651 Normally the environment is loaded when the board is
2652 initialised so that it is available to U-Boot. This inhibits
2653 that so that the environment is not available until
2654 explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL
2655 this is instead controlled by the value of
2656 /config/load-environment.
2658 - DataFlash Support:
2659 CONFIG_HAS_DATAFLASH
2661 Defining this option enables DataFlash features and
2662 allows to read/write in Dataflash via the standard
2665 - Serial Flash support
2668 Defining this option enables SPI flash commands
2669 'sf probe/read/write/erase/update'.
2671 Usage requires an initial 'probe' to define the serial
2672 flash parameters, followed by read/write/erase/update
2675 The following defaults may be provided by the platform
2676 to handle the common case when only a single serial
2677 flash is present on the system.
2679 CONFIG_SF_DEFAULT_BUS Bus identifier
2680 CONFIG_SF_DEFAULT_CS Chip-select
2681 CONFIG_SF_DEFAULT_MODE (see include/spi.h)
2682 CONFIG_SF_DEFAULT_SPEED in Hz
2686 Define this option to include a destructive SPI flash
2689 CONFIG_SF_DUAL_FLASH Dual flash memories
2691 Define this option to use dual flash support where two flash
2692 memories can be connected with a given cs line.
2693 Currently Xilinx Zynq qspi supports these type of connections.
2695 - SystemACE Support:
2698 Adding this option adds support for Xilinx SystemACE
2699 chips attached via some sort of local bus. The address
2700 of the chip must also be defined in the
2701 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
2703 #define CONFIG_SYSTEMACE
2704 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
2706 When SystemACE support is added, the "ace" device type
2707 becomes available to the fat commands, i.e. fatls.
2709 - TFTP Fixed UDP Port:
2712 If this is defined, the environment variable tftpsrcp
2713 is used to supply the TFTP UDP source port value.
2714 If tftpsrcp isn't defined, the normal pseudo-random port
2715 number generator is used.
2717 Also, the environment variable tftpdstp is used to supply
2718 the TFTP UDP destination port value. If tftpdstp isn't
2719 defined, the normal port 69 is used.
2721 The purpose for tftpsrcp is to allow a TFTP server to
2722 blindly start the TFTP transfer using the pre-configured
2723 target IP address and UDP port. This has the effect of
2724 "punching through" the (Windows XP) firewall, allowing
2725 the remainder of the TFTP transfer to proceed normally.
2726 A better solution is to properly configure the firewall,
2727 but sometimes that is not allowed.
2732 This enables a generic 'hash' command which can produce
2733 hashes / digests from a few algorithms (e.g. SHA1, SHA256).
2737 Enable the hash verify command (hash -v). This adds to code
2740 Note: There is also a sha1sum command, which should perhaps
2741 be deprecated in favour of 'hash sha1'.
2743 - Freescale i.MX specific commands:
2744 CONFIG_CMD_HDMIDETECT
2745 This enables 'hdmidet' command which returns true if an
2746 HDMI monitor is detected. This command is i.MX 6 specific.
2748 - bootcount support:
2749 CONFIG_BOOTCOUNT_LIMIT
2751 This enables the bootcounter support, see:
2752 http://www.denx.de/wiki/DULG/UBootBootCountLimit
2755 enable special bootcounter support on at91sam9xe based boards.
2757 enable special bootcounter support on da850 based boards.
2758 CONFIG_BOOTCOUNT_RAM
2759 enable support for the bootcounter in RAM
2760 CONFIG_BOOTCOUNT_I2C
2761 enable support for the bootcounter on an i2c (like RTC) device.
2762 CONFIG_SYS_I2C_RTC_ADDR = i2c chip address
2763 CONFIG_SYS_BOOTCOUNT_ADDR = i2c addr which is used for
2765 CONFIG_BOOTCOUNT_ALEN = address len
2767 - Show boot progress:
2768 CONFIG_SHOW_BOOT_PROGRESS
2770 Defining this option allows to add some board-
2771 specific code (calling a user-provided function
2772 "show_boot_progress(int)") that enables you to show
2773 the system's boot progress on some display (for
2774 example, some LED's) on your board. At the moment,
2775 the following checkpoints are implemented:
2778 Legacy uImage format:
2781 1 common/cmd_bootm.c before attempting to boot an image
2782 -1 common/cmd_bootm.c Image header has bad magic number
2783 2 common/cmd_bootm.c Image header has correct magic number
2784 -2 common/cmd_bootm.c Image header has bad checksum
2785 3 common/cmd_bootm.c Image header has correct checksum
2786 -3 common/cmd_bootm.c Image data has bad checksum
2787 4 common/cmd_bootm.c Image data has correct checksum
2788 -4 common/cmd_bootm.c Image is for unsupported architecture
2789 5 common/cmd_bootm.c Architecture check OK
2790 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
2791 6 common/cmd_bootm.c Image Type check OK
2792 -6 common/cmd_bootm.c gunzip uncompression error
2793 -7 common/cmd_bootm.c Unimplemented compression type
2794 7 common/cmd_bootm.c Uncompression OK
2795 8 common/cmd_bootm.c No uncompress/copy overwrite error
2796 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
2798 9 common/image.c Start initial ramdisk verification
2799 -10 common/image.c Ramdisk header has bad magic number
2800 -11 common/image.c Ramdisk header has bad checksum
2801 10 common/image.c Ramdisk header is OK
2802 -12 common/image.c Ramdisk data has bad checksum
2803 11 common/image.c Ramdisk data has correct checksum
2804 12 common/image.c Ramdisk verification complete, start loading
2805 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
2806 13 common/image.c Start multifile image verification
2807 14 common/image.c No initial ramdisk, no multifile, continue.
2809 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
2811 -30 arch/powerpc/lib/board.c Fatal error, hang the system
2812 -31 post/post.c POST test failed, detected by post_output_backlog()
2813 -32 post/post.c POST test failed, detected by post_run_single()
2815 34 common/cmd_doc.c before loading a Image from a DOC device
2816 -35 common/cmd_doc.c Bad usage of "doc" command
2817 35 common/cmd_doc.c correct usage of "doc" command
2818 -36 common/cmd_doc.c No boot device
2819 36 common/cmd_doc.c correct boot device
2820 -37 common/cmd_doc.c Unknown Chip ID on boot device
2821 37 common/cmd_doc.c correct chip ID found, device available
2822 -38 common/cmd_doc.c Read Error on boot device
2823 38 common/cmd_doc.c reading Image header from DOC device OK
2824 -39 common/cmd_doc.c Image header has bad magic number
2825 39 common/cmd_doc.c Image header has correct magic number
2826 -40 common/cmd_doc.c Error reading Image from DOC device
2827 40 common/cmd_doc.c Image header has correct magic number
2828 41 common/cmd_ide.c before loading a Image from a IDE device
2829 -42 common/cmd_ide.c Bad usage of "ide" command
2830 42 common/cmd_ide.c correct usage of "ide" command
2831 -43 common/cmd_ide.c No boot device
2832 43 common/cmd_ide.c boot device found
2833 -44 common/cmd_ide.c Device not available
2834 44 common/cmd_ide.c Device available
2835 -45 common/cmd_ide.c wrong partition selected
2836 45 common/cmd_ide.c partition selected
2837 -46 common/cmd_ide.c Unknown partition table
2838 46 common/cmd_ide.c valid partition table found
2839 -47 common/cmd_ide.c Invalid partition type
2840 47 common/cmd_ide.c correct partition type
2841 -48 common/cmd_ide.c Error reading Image Header on boot device
2842 48 common/cmd_ide.c reading Image Header from IDE device OK
2843 -49 common/cmd_ide.c Image header has bad magic number
2844 49 common/cmd_ide.c Image header has correct magic number
2845 -50 common/cmd_ide.c Image header has bad checksum
2846 50 common/cmd_ide.c Image header has correct checksum
2847 -51 common/cmd_ide.c Error reading Image from IDE device
2848 51 common/cmd_ide.c reading Image from IDE device OK
2849 52 common/cmd_nand.c before loading a Image from a NAND device
2850 -53 common/cmd_nand.c Bad usage of "nand" command
2851 53 common/cmd_nand.c correct usage of "nand" command
2852 -54 common/cmd_nand.c No boot device
2853 54 common/cmd_nand.c boot device found
2854 -55 common/cmd_nand.c Unknown Chip ID on boot device
2855 55 common/cmd_nand.c correct chip ID found, device available
2856 -56 common/cmd_nand.c Error reading Image Header on boot device
2857 56 common/cmd_nand.c reading Image Header from NAND device OK
2858 -57 common/cmd_nand.c Image header has bad magic number
2859 57 common/cmd_nand.c Image header has correct magic number
2860 -58 common/cmd_nand.c Error reading Image from NAND device
2861 58 common/cmd_nand.c reading Image from NAND device OK
2863 -60 common/env_common.c Environment has a bad CRC, using default
2865 64 net/eth.c starting with Ethernet configuration.
2866 -64 net/eth.c no Ethernet found.
2867 65 net/eth.c Ethernet found.
2869 -80 common/cmd_net.c usage wrong
2870 80 common/cmd_net.c before calling net_loop()
2871 -81 common/cmd_net.c some error in net_loop() occurred
2872 81 common/cmd_net.c net_loop() back without error
2873 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
2874 82 common/cmd_net.c trying automatic boot
2875 83 common/cmd_net.c running "source" command
2876 -83 common/cmd_net.c some error in automatic boot or "source" command
2877 84 common/cmd_net.c end without errors
2882 100 common/cmd_bootm.c Kernel FIT Image has correct format
2883 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
2884 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
2885 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
2886 102 common/cmd_bootm.c Kernel unit name specified
2887 -103 common/cmd_bootm.c Can't get kernel subimage node offset
2888 103 common/cmd_bootm.c Found configuration node
2889 104 common/cmd_bootm.c Got kernel subimage node offset
2890 -104 common/cmd_bootm.c Kernel subimage hash verification failed
2891 105 common/cmd_bootm.c Kernel subimage hash verification OK
2892 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
2893 106 common/cmd_bootm.c Architecture check OK
2894 -106 common/cmd_bootm.c Kernel subimage has wrong type
2895 107 common/cmd_bootm.c Kernel subimage type OK
2896 -107 common/cmd_bootm.c Can't get kernel subimage data/size
2897 108 common/cmd_bootm.c Got kernel subimage data/size
2898 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
2899 -109 common/cmd_bootm.c Can't get kernel subimage type
2900 -110 common/cmd_bootm.c Can't get kernel subimage comp
2901 -111 common/cmd_bootm.c Can't get kernel subimage os
2902 -112 common/cmd_bootm.c Can't get kernel subimage load address
2903 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
2905 120 common/image.c Start initial ramdisk verification
2906 -120 common/image.c Ramdisk FIT image has incorrect format
2907 121 common/image.c Ramdisk FIT image has correct format
2908 122 common/image.c No ramdisk subimage unit name, using configuration
2909 -122 common/image.c Can't get configuration for ramdisk subimage
2910 123 common/image.c Ramdisk unit name specified
2911 -124 common/image.c Can't get ramdisk subimage node offset
2912 125 common/image.c Got ramdisk subimage node offset
2913 -125 common/image.c Ramdisk subimage hash verification failed
2914 126 common/image.c Ramdisk subimage hash verification OK
2915 -126 common/image.c Ramdisk subimage for unsupported architecture
2916 127 common/image.c Architecture check OK
2917 -127 common/image.c Can't get ramdisk subimage data/size
2918 128 common/image.c Got ramdisk subimage data/size
2919 129 common/image.c Can't get ramdisk load address
2920 -129 common/image.c Got ramdisk load address
2922 -130 common/cmd_doc.c Incorrect FIT image format
2923 131 common/cmd_doc.c FIT image format OK
2925 -140 common/cmd_ide.c Incorrect FIT image format
2926 141 common/cmd_ide.c FIT image format OK
2928 -150 common/cmd_nand.c Incorrect FIT image format
2929 151 common/cmd_nand.c FIT image format OK
2931 - legacy image format:
2932 CONFIG_IMAGE_FORMAT_LEGACY
2933 enables the legacy image format support in U-Boot.
2936 enabled if CONFIG_FIT_SIGNATURE is not defined.
2938 CONFIG_DISABLE_IMAGE_LEGACY
2939 disable the legacy image format
2941 This define is introduced, as the legacy image format is
2942 enabled per default for backward compatibility.
2944 - Standalone program support:
2945 CONFIG_STANDALONE_LOAD_ADDR
2947 This option defines a board specific value for the
2948 address where standalone program gets loaded, thus
2949 overwriting the architecture dependent default
2952 - Frame Buffer Address:
2955 Define CONFIG_FB_ADDR if you want to use specific
2956 address for frame buffer. This is typically the case
2957 when using a graphics controller has separate video
2958 memory. U-Boot will then place the frame buffer at
2959 the given address instead of dynamically reserving it
2960 in system RAM by calling lcd_setmem(), which grabs
2961 the memory for the frame buffer depending on the
2962 configured panel size.
2964 Please see board_init_f function.
2966 - Automatic software updates via TFTP server
2968 CONFIG_UPDATE_TFTP_CNT_MAX
2969 CONFIG_UPDATE_TFTP_MSEC_MAX
2971 These options enable and control the auto-update feature;
2972 for a more detailed description refer to doc/README.update.
2974 - MTD Support (mtdparts command, UBI support)
2977 Adds the MTD device infrastructure from the Linux kernel.
2978 Needed for mtdparts command support.
2980 CONFIG_MTD_PARTITIONS
2982 Adds the MTD partitioning infrastructure from the Linux
2983 kernel. Needed for UBI support.
2988 Adds commands for interacting with MTD partitions formatted
2989 with the UBI flash translation layer
2991 Requires also defining CONFIG_RBTREE
2993 CONFIG_UBI_SILENCE_MSG
2995 Make the verbose messages from UBI stop printing. This leaves
2996 warnings and errors enabled.
2999 CONFIG_MTD_UBI_WL_THRESHOLD
3000 This parameter defines the maximum difference between the highest
3001 erase counter value and the lowest erase counter value of eraseblocks
3002 of UBI devices. When this threshold is exceeded, UBI starts performing
3003 wear leveling by means of moving data from eraseblock with low erase
3004 counter to eraseblocks with high erase counter.
3006 The default value should be OK for SLC NAND flashes, NOR flashes and
3007 other flashes which have eraseblock life-cycle 100000 or more.
3008 However, in case of MLC NAND flashes which typically have eraseblock
3009 life-cycle less than 10000, the threshold should be lessened (e.g.,
3010 to 128 or 256, although it does not have to be power of 2).
3014 CONFIG_MTD_UBI_BEB_LIMIT
3015 This option specifies the maximum bad physical eraseblocks UBI
3016 expects on the MTD device (per 1024 eraseblocks). If the
3017 underlying flash does not admit of bad eraseblocks (e.g. NOR
3018 flash), this value is ignored.
3020 NAND datasheets often specify the minimum and maximum NVM
3021 (Number of Valid Blocks) for the flashes' endurance lifetime.
3022 The maximum expected bad eraseblocks per 1024 eraseblocks
3023 then can be calculated as "1024 * (1 - MinNVB / MaxNVB)",
3024 which gives 20 for most NANDs (MaxNVB is basically the total
3025 count of eraseblocks on the chip).
3027 To put it differently, if this value is 20, UBI will try to
3028 reserve about 1.9% of physical eraseblocks for bad blocks
3029 handling. And that will be 1.9% of eraseblocks on the entire
3030 NAND chip, not just the MTD partition UBI attaches. This means
3031 that if you have, say, a NAND flash chip admits maximum 40 bad
3032 eraseblocks, and it is split on two MTD partitions of the same
3033 size, UBI will reserve 40 eraseblocks when attaching a
3038 CONFIG_MTD_UBI_FASTMAP
3039 Fastmap is a mechanism which allows attaching an UBI device
3040 in nearly constant time. Instead of scanning the whole MTD device it
3041 only has to locate a checkpoint (called fastmap) on the device.
3042 The on-flash fastmap contains all information needed to attach
3043 the device. Using fastmap makes only sense on large devices where
3044 attaching by scanning takes long. UBI will not automatically install
3045 a fastmap on old images, but you can set the UBI parameter
3046 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT to 1 if you want so. Please note
3047 that fastmap-enabled images are still usable with UBI implementations
3048 without fastmap support. On typical flash devices the whole fastmap
3049 fits into one PEB. UBI will reserve PEBs to hold two fastmaps.
3051 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT
3052 Set this parameter to enable fastmap automatically on images
3056 CONFIG_MTD_UBI_FM_DEBUG
3057 Enable UBI fastmap debug
3063 Adds commands for interacting with UBI volumes formatted as
3064 UBIFS. UBIFS is read-only in u-boot.
3066 Requires UBI support as well as CONFIG_LZO
3068 CONFIG_UBIFS_SILENCE_MSG
3070 Make the verbose messages from UBIFS stop printing. This leaves
3071 warnings and errors enabled.
3075 Enable building of SPL globally.
3078 LDSCRIPT for linking the SPL binary.
3080 CONFIG_SPL_MAX_FOOTPRINT
3081 Maximum size in memory allocated to the SPL, BSS included.
3082 When defined, the linker checks that the actual memory
3083 used by SPL from _start to __bss_end does not exceed it.
3084 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3085 must not be both defined at the same time.
3088 Maximum size of the SPL image (text, data, rodata, and
3089 linker lists sections), BSS excluded.
3090 When defined, the linker checks that the actual size does
3093 CONFIG_SPL_TEXT_BASE
3094 TEXT_BASE for linking the SPL binary.
3096 CONFIG_SPL_RELOC_TEXT_BASE
3097 Address to relocate to. If unspecified, this is equal to
3098 CONFIG_SPL_TEXT_BASE (i.e. no relocation is done).
3100 CONFIG_SPL_BSS_START_ADDR
3101 Link address for the BSS within the SPL binary.
3103 CONFIG_SPL_BSS_MAX_SIZE
3104 Maximum size in memory allocated to the SPL BSS.
3105 When defined, the linker checks that the actual memory used
3106 by SPL from __bss_start to __bss_end does not exceed it.
3107 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3108 must not be both defined at the same time.
3111 Adress of the start of the stack SPL will use
3113 CONFIG_SPL_PANIC_ON_RAW_IMAGE
3114 When defined, SPL will panic() if the image it has
3115 loaded does not have a signature.
3116 Defining this is useful when code which loads images
3117 in SPL cannot guarantee that absolutely all read errors
3119 An example is the LPC32XX MLC NAND driver, which will
3120 consider that a completely unreadable NAND block is bad,
3121 and thus should be skipped silently.
3123 CONFIG_SPL_RELOC_STACK
3124 Adress of the start of the stack SPL will use after
3125 relocation. If unspecified, this is equal to
3128 CONFIG_SYS_SPL_MALLOC_START
3129 Starting address of the malloc pool used in SPL.
3130 When this option is set the full malloc is used in SPL and
3131 it is set up by spl_init() and before that, the simple malloc()
3132 can be used if CONFIG_SYS_MALLOC_F is defined.
3134 CONFIG_SYS_SPL_MALLOC_SIZE
3135 The size of the malloc pool used in SPL.
3137 CONFIG_SPL_FRAMEWORK
3138 Enable the SPL framework under common/. This framework
3139 supports MMC, NAND and YMODEM loading of U-Boot and NAND
3140 NAND loading of the Linux Kernel.
3143 Enable booting directly to an OS from SPL.
3144 See also: doc/README.falcon
3146 CONFIG_SPL_DISPLAY_PRINT
3147 For ARM, enable an optional function to print more information
3148 about the running system.
3150 CONFIG_SPL_INIT_MINIMAL
3151 Arch init code should be built for a very small image
3153 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_PARTITION
3154 Partition on the MMC to load U-Boot from when the MMC is being
3157 CONFIG_SYS_MMCSD_RAW_MODE_KERNEL_SECTOR
3158 Sector to load kernel uImage from when MMC is being
3159 used in raw mode (for Falcon mode)
3161 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTOR,
3162 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTORS
3163 Sector and number of sectors to load kernel argument
3164 parameters from when MMC is being used in raw mode
3167 CONFIG_SYS_MMCSD_FS_BOOT_PARTITION
3168 Partition on the MMC to load U-Boot from when the MMC is being
3171 CONFIG_SPL_FS_LOAD_PAYLOAD_NAME
3172 Filename to read to load U-Boot when reading from filesystem
3174 CONFIG_SPL_FS_LOAD_KERNEL_NAME
3175 Filename to read to load kernel uImage when reading
3176 from filesystem (for Falcon mode)
3178 CONFIG_SPL_FS_LOAD_ARGS_NAME
3179 Filename to read to load kernel argument parameters
3180 when reading from filesystem (for Falcon mode)
3182 CONFIG_SPL_MPC83XX_WAIT_FOR_NAND
3183 Set this for NAND SPL on PPC mpc83xx targets, so that
3184 start.S waits for the rest of the SPL to load before
3185 continuing (the hardware starts execution after just
3186 loading the first page rather than the full 4K).
3188 CONFIG_SPL_SKIP_RELOCATE
3189 Avoid SPL relocation
3191 CONFIG_SPL_NAND_BASE
3192 Include nand_base.c in the SPL. Requires
3193 CONFIG_SPL_NAND_DRIVERS.
3195 CONFIG_SPL_NAND_DRIVERS
3196 SPL uses normal NAND drivers, not minimal drivers.
3199 Include standard software ECC in the SPL
3201 CONFIG_SPL_NAND_SIMPLE
3202 Support for NAND boot using simple NAND drivers that
3203 expose the cmd_ctrl() interface.
3206 Support for a lightweight UBI (fastmap) scanner and
3209 CONFIG_SPL_NAND_RAW_ONLY
3210 Support to boot only raw u-boot.bin images. Use this only
3211 if you need to save space.
3213 CONFIG_SPL_COMMON_INIT_DDR
3214 Set for common ddr init with serial presence detect in
3217 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
3218 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
3219 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
3220 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
3221 CONFIG_SYS_NAND_ECCBYTES
3222 Defines the size and behavior of the NAND that SPL uses
3225 CONFIG_SPL_NAND_BOOT
3226 Add support NAND boot
3228 CONFIG_SYS_NAND_U_BOOT_OFFS
3229 Location in NAND to read U-Boot from
3231 CONFIG_SYS_NAND_U_BOOT_DST
3232 Location in memory to load U-Boot to
3234 CONFIG_SYS_NAND_U_BOOT_SIZE
3235 Size of image to load
3237 CONFIG_SYS_NAND_U_BOOT_START
3238 Entry point in loaded image to jump to
3240 CONFIG_SYS_NAND_HW_ECC_OOBFIRST
3241 Define this if you need to first read the OOB and then the
3242 data. This is used, for example, on davinci platforms.
3244 CONFIG_SPL_OMAP3_ID_NAND
3245 Support for an OMAP3-specific set of functions to return the
3246 ID and MFR of the first attached NAND chip, if present.
3248 CONFIG_SPL_RAM_DEVICE
3249 Support for running image already present in ram, in SPL binary
3252 Image offset to which the SPL should be padded before appending
3253 the SPL payload. By default, this is defined as
3254 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3255 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3256 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3259 Final target image containing SPL and payload. Some SPLs
3260 use an arch-specific makefile fragment instead, for
3261 example if more than one image needs to be produced.
3263 CONFIG_FIT_SPL_PRINT
3264 Printing information about a FIT image adds quite a bit of
3265 code to SPL. So this is normally disabled in SPL. Use this
3266 option to re-enable it. This will affect the output of the
3267 bootm command when booting a FIT image.
3271 Enable building of TPL globally.
3274 Image offset to which the TPL should be padded before appending
3275 the TPL payload. By default, this is defined as
3276 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3277 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3278 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3280 - Interrupt support (PPC):
3282 There are common interrupt_init() and timer_interrupt()
3283 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
3284 for CPU specific initialization. interrupt_init_cpu()
3285 should set decrementer_count to appropriate value. If
3286 CPU resets decrementer automatically after interrupt
3287 (ppc4xx) it should set decrementer_count to zero.
3288 timer_interrupt() calls timer_interrupt_cpu() for CPU
3289 specific handling. If board has watchdog / status_led
3290 / other_activity_monitor it works automatically from
3291 general timer_interrupt().
3294 Board initialization settings:
3295 ------------------------------
3297 During Initialization u-boot calls a number of board specific functions
3298 to allow the preparation of board specific prerequisites, e.g. pin setup
3299 before drivers are initialized. To enable these callbacks the
3300 following configuration macros have to be defined. Currently this is
3301 architecture specific, so please check arch/your_architecture/lib/board.c
3302 typically in board_init_f() and board_init_r().
3304 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
3305 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
3306 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
3307 - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
3309 Configuration Settings:
3310 -----------------------
3312 - CONFIG_SYS_SUPPORT_64BIT_DATA: Defined automatically if compiled as 64-bit.
3313 Optionally it can be defined to support 64-bit memory commands.
3315 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
3316 undefine this when you're short of memory.
3318 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
3319 width of the commands listed in the 'help' command output.
3321 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
3322 prompt for user input.
3324 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
3326 - CONFIG_SYS_PBSIZE: Buffer size for Console output
3328 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
3330 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
3331 the application (usually a Linux kernel) when it is
3334 - CONFIG_SYS_BAUDRATE_TABLE:
3335 List of legal baudrate settings for this board.
3337 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
3338 Begin and End addresses of the area used by the
3341 - CONFIG_SYS_ALT_MEMTEST:
3342 Enable an alternate, more extensive memory test.
3344 - CONFIG_SYS_MEMTEST_SCRATCH:
3345 Scratch address used by the alternate memory test
3346 You only need to set this if address zero isn't writeable
3348 - CONFIG_SYS_MEM_RESERVE_SECURE
3349 Only implemented for ARMv8 for now.
3350 If defined, the size of CONFIG_SYS_MEM_RESERVE_SECURE memory
3351 is substracted from total RAM and won't be reported to OS.
3352 This memory can be used as secure memory. A variable
3353 gd->arch.secure_ram is used to track the location. In systems
3354 the RAM base is not zero, or RAM is divided into banks,
3355 this variable needs to be recalcuated to get the address.
3357 - CONFIG_SYS_MEM_TOP_HIDE:
3358 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
3359 this specified memory area will get subtracted from the top
3360 (end) of RAM and won't get "touched" at all by U-Boot. By
3361 fixing up gd->ram_size the Linux kernel should gets passed
3362 the now "corrected" memory size and won't touch it either.
3363 This should work for arch/ppc and arch/powerpc. Only Linux
3364 board ports in arch/powerpc with bootwrapper support that
3365 recalculate the memory size from the SDRAM controller setup
3366 will have to get fixed in Linux additionally.
3368 This option can be used as a workaround for the 440EPx/GRx
3369 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
3372 WARNING: Please make sure that this value is a multiple of
3373 the Linux page size (normally 4k). If this is not the case,
3374 then the end address of the Linux memory will be located at a
3375 non page size aligned address and this could cause major
3378 - CONFIG_SYS_LOADS_BAUD_CHANGE:
3379 Enable temporary baudrate change while serial download
3381 - CONFIG_SYS_SDRAM_BASE:
3382 Physical start address of SDRAM. _Must_ be 0 here.
3384 - CONFIG_SYS_FLASH_BASE:
3385 Physical start address of Flash memory.
3387 - CONFIG_SYS_MONITOR_BASE:
3388 Physical start address of boot monitor code (set by
3389 make config files to be same as the text base address
3390 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
3391 CONFIG_SYS_FLASH_BASE when booting from flash.
3393 - CONFIG_SYS_MONITOR_LEN:
3394 Size of memory reserved for monitor code, used to
3395 determine _at_compile_time_ (!) if the environment is
3396 embedded within the U-Boot image, or in a separate
3399 - CONFIG_SYS_MALLOC_LEN:
3400 Size of DRAM reserved for malloc() use.
3402 - CONFIG_SYS_MALLOC_F_LEN
3403 Size of the malloc() pool for use before relocation. If
3404 this is defined, then a very simple malloc() implementation
3405 will become available before relocation. The address is just
3406 below the global data, and the stack is moved down to make
3409 This feature allocates regions with increasing addresses
3410 within the region. calloc() is supported, but realloc()
3411 is not available. free() is supported but does nothing.
3412 The memory will be freed (or in fact just forgotten) when
3413 U-Boot relocates itself.
3415 - CONFIG_SYS_MALLOC_SIMPLE
3416 Provides a simple and small malloc() and calloc() for those
3417 boards which do not use the full malloc in SPL (which is
3418 enabled with CONFIG_SYS_SPL_MALLOC_START).
3420 - CONFIG_SYS_NONCACHED_MEMORY:
3421 Size of non-cached memory area. This area of memory will be
3422 typically located right below the malloc() area and mapped
3423 uncached in the MMU. This is useful for drivers that would
3424 otherwise require a lot of explicit cache maintenance. For
3425 some drivers it's also impossible to properly maintain the
3426 cache. For example if the regions that need to be flushed
3427 are not a multiple of the cache-line size, *and* padding
3428 cannot be allocated between the regions to align them (i.e.
3429 if the HW requires a contiguous array of regions, and the
3430 size of each region is not cache-aligned), then a flush of
3431 one region may result in overwriting data that hardware has
3432 written to another region in the same cache-line. This can
3433 happen for example in network drivers where descriptors for
3434 buffers are typically smaller than the CPU cache-line (e.g.
3435 16 bytes vs. 32 or 64 bytes).
3437 Non-cached memory is only supported on 32-bit ARM at present.
3439 - CONFIG_SYS_BOOTM_LEN:
3440 Normally compressed uImages are limited to an
3441 uncompressed size of 8 MBytes. If this is not enough,
3442 you can define CONFIG_SYS_BOOTM_LEN in your board config file
3443 to adjust this setting to your needs.
3445 - CONFIG_SYS_BOOTMAPSZ:
3446 Maximum size of memory mapped by the startup code of
3447 the Linux kernel; all data that must be processed by
3448 the Linux kernel (bd_info, boot arguments, FDT blob if
3449 used) must be put below this limit, unless "bootm_low"
3450 environment variable is defined and non-zero. In such case
3451 all data for the Linux kernel must be between "bootm_low"
3452 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
3453 variable "bootm_mapsize" will override the value of
3454 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
3455 then the value in "bootm_size" will be used instead.
3457 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
3458 Enable initrd_high functionality. If defined then the
3459 initrd_high feature is enabled and the bootm ramdisk subcommand
3462 - CONFIG_SYS_BOOT_GET_CMDLINE:
3463 Enables allocating and saving kernel cmdline in space between
3464 "bootm_low" and "bootm_low" + BOOTMAPSZ.
3466 - CONFIG_SYS_BOOT_GET_KBD:
3467 Enables allocating and saving a kernel copy of the bd_info in
3468 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
3470 - CONFIG_SYS_MAX_FLASH_BANKS:
3471 Max number of Flash memory banks
3473 - CONFIG_SYS_MAX_FLASH_SECT:
3474 Max number of sectors on a Flash chip
3476 - CONFIG_SYS_FLASH_ERASE_TOUT:
3477 Timeout for Flash erase operations (in ms)
3479 - CONFIG_SYS_FLASH_WRITE_TOUT:
3480 Timeout for Flash write operations (in ms)
3482 - CONFIG_SYS_FLASH_LOCK_TOUT
3483 Timeout for Flash set sector lock bit operation (in ms)
3485 - CONFIG_SYS_FLASH_UNLOCK_TOUT
3486 Timeout for Flash clear lock bits operation (in ms)
3488 - CONFIG_SYS_FLASH_PROTECTION
3489 If defined, hardware flash sectors protection is used
3490 instead of U-Boot software protection.
3492 - CONFIG_SYS_DIRECT_FLASH_TFTP:
3494 Enable TFTP transfers directly to flash memory;
3495 without this option such a download has to be
3496 performed in two steps: (1) download to RAM, and (2)
3497 copy from RAM to flash.
3499 The two-step approach is usually more reliable, since
3500 you can check if the download worked before you erase
3501 the flash, but in some situations (when system RAM is
3502 too limited to allow for a temporary copy of the
3503 downloaded image) this option may be very useful.
3505 - CONFIG_SYS_FLASH_CFI:
3506 Define if the flash driver uses extra elements in the
3507 common flash structure for storing flash geometry.
3509 - CONFIG_FLASH_CFI_DRIVER
3510 This option also enables the building of the cfi_flash driver
3511 in the drivers directory
3513 - CONFIG_FLASH_CFI_MTD
3514 This option enables the building of the cfi_mtd driver
3515 in the drivers directory. The driver exports CFI flash
3518 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
3519 Use buffered writes to flash.
3521 - CONFIG_FLASH_SPANSION_S29WS_N
3522 s29ws-n MirrorBit flash has non-standard addresses for buffered
3525 - CONFIG_SYS_FLASH_QUIET_TEST
3526 If this option is defined, the common CFI flash doesn't
3527 print it's warning upon not recognized FLASH banks. This
3528 is useful, if some of the configured banks are only
3529 optionally available.
3531 - CONFIG_FLASH_SHOW_PROGRESS
3532 If defined (must be an integer), print out countdown
3533 digits and dots. Recommended value: 45 (9..1) for 80
3534 column displays, 15 (3..1) for 40 column displays.
3536 - CONFIG_FLASH_VERIFY
3537 If defined, the content of the flash (destination) is compared
3538 against the source after the write operation. An error message
3539 will be printed when the contents are not identical.
3540 Please note that this option is useless in nearly all cases,
3541 since such flash programming errors usually are detected earlier
3542 while unprotecting/erasing/programming. Please only enable
3543 this option if you really know what you are doing.
3545 - CONFIG_SYS_RX_ETH_BUFFER:
3546 Defines the number of Ethernet receive buffers. On some
3547 Ethernet controllers it is recommended to set this value
3548 to 8 or even higher (EEPRO100 or 405 EMAC), since all
3549 buffers can be full shortly after enabling the interface
3550 on high Ethernet traffic.
3551 Defaults to 4 if not defined.
3553 - CONFIG_ENV_MAX_ENTRIES
3555 Maximum number of entries in the hash table that is used
3556 internally to store the environment settings. The default
3557 setting is supposed to be generous and should work in most
3558 cases. This setting can be used to tune behaviour; see
3559 lib/hashtable.c for details.
3561 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3562 - CONFIG_ENV_FLAGS_LIST_STATIC
3563 Enable validation of the values given to environment variables when
3564 calling env set. Variables can be restricted to only decimal,
3565 hexadecimal, or boolean. If CONFIG_CMD_NET is also defined,
3566 the variables can also be restricted to IP address or MAC address.
3568 The format of the list is:
3569 type_attribute = [s|d|x|b|i|m]
3570 access_attribute = [a|r|o|c]
3571 attributes = type_attribute[access_attribute]
3572 entry = variable_name[:attributes]
3575 The type attributes are:
3576 s - String (default)
3579 b - Boolean ([1yYtT|0nNfF])
3583 The access attributes are:
3589 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3590 Define this to a list (string) to define the ".flags"
3591 environment variable in the default or embedded environment.
3593 - CONFIG_ENV_FLAGS_LIST_STATIC
3594 Define this to a list (string) to define validation that
3595 should be done if an entry is not found in the ".flags"
3596 environment variable. To override a setting in the static
3597 list, simply add an entry for the same variable name to the
3600 If CONFIG_REGEX is defined, the variable_name above is evaluated as a
3601 regular expression. This allows multiple variables to define the same
3602 flags without explicitly listing them for each variable.
3604 - CONFIG_ENV_ACCESS_IGNORE_FORCE
3605 If defined, don't allow the -f switch to env set override variable
3609 If stdint.h is available with your toolchain you can define this
3610 option to enable it. You can provide option 'USE_STDINT=1' when
3611 building U-Boot to enable this.
3613 The following definitions that deal with the placement and management
3614 of environment data (variable area); in general, we support the
3615 following configurations:
3617 - CONFIG_BUILD_ENVCRC:
3619 Builds up envcrc with the target environment so that external utils
3620 may easily extract it and embed it in final U-Boot images.
3622 - CONFIG_ENV_IS_IN_FLASH:
3624 Define this if the environment is in flash memory.
3626 a) The environment occupies one whole flash sector, which is
3627 "embedded" in the text segment with the U-Boot code. This
3628 happens usually with "bottom boot sector" or "top boot
3629 sector" type flash chips, which have several smaller
3630 sectors at the start or the end. For instance, such a
3631 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
3632 such a case you would place the environment in one of the
3633 4 kB sectors - with U-Boot code before and after it. With
3634 "top boot sector" type flash chips, you would put the
3635 environment in one of the last sectors, leaving a gap
3636 between U-Boot and the environment.
3638 - CONFIG_ENV_OFFSET:
3640 Offset of environment data (variable area) to the
3641 beginning of flash memory; for instance, with bottom boot
3642 type flash chips the second sector can be used: the offset
3643 for this sector is given here.
3645 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
3649 This is just another way to specify the start address of
3650 the flash sector containing the environment (instead of
3653 - CONFIG_ENV_SECT_SIZE:
3655 Size of the sector containing the environment.
3658 b) Sometimes flash chips have few, equal sized, BIG sectors.
3659 In such a case you don't want to spend a whole sector for
3664 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
3665 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
3666 of this flash sector for the environment. This saves
3667 memory for the RAM copy of the environment.
3669 It may also save flash memory if you decide to use this
3670 when your environment is "embedded" within U-Boot code,
3671 since then the remainder of the flash sector could be used
3672 for U-Boot code. It should be pointed out that this is
3673 STRONGLY DISCOURAGED from a robustness point of view:
3674 updating the environment in flash makes it always
3675 necessary to erase the WHOLE sector. If something goes
3676 wrong before the contents has been restored from a copy in
3677 RAM, your target system will be dead.
3679 - CONFIG_ENV_ADDR_REDUND
3680 CONFIG_ENV_SIZE_REDUND
3682 These settings describe a second storage area used to hold
3683 a redundant copy of the environment data, so that there is
3684 a valid backup copy in case there is a power failure during
3685 a "saveenv" operation.
3687 BE CAREFUL! Any changes to the flash layout, and some changes to the
3688 source code will make it necessary to adapt <board>/u-boot.lds*
3692 - CONFIG_ENV_IS_IN_NVRAM:
3694 Define this if you have some non-volatile memory device
3695 (NVRAM, battery buffered SRAM) which you want to use for the
3701 These two #defines are used to determine the memory area you
3702 want to use for environment. It is assumed that this memory
3703 can just be read and written to, without any special
3706 BE CAREFUL! The first access to the environment happens quite early
3707 in U-Boot initialization (when we try to get the setting of for the
3708 console baudrate). You *MUST* have mapped your NVRAM area then, or
3711 Please note that even with NVRAM we still use a copy of the
3712 environment in RAM: we could work on NVRAM directly, but we want to
3713 keep settings there always unmodified except somebody uses "saveenv"
3714 to save the current settings.
3717 - CONFIG_ENV_IS_IN_EEPROM:
3719 Use this if you have an EEPROM or similar serial access
3720 device and a driver for it.
3722 - CONFIG_ENV_OFFSET:
3725 These two #defines specify the offset and size of the
3726 environment area within the total memory of your EEPROM.
3728 - CONFIG_SYS_I2C_EEPROM_ADDR:
3729 If defined, specified the chip address of the EEPROM device.
3730 The default address is zero.
3732 - CONFIG_SYS_I2C_EEPROM_BUS:
3733 If defined, specified the i2c bus of the EEPROM device.
3735 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
3736 If defined, the number of bits used to address bytes in a
3737 single page in the EEPROM device. A 64 byte page, for example
3738 would require six bits.
3740 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
3741 If defined, the number of milliseconds to delay between
3742 page writes. The default is zero milliseconds.
3744 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
3745 The length in bytes of the EEPROM memory array address. Note
3746 that this is NOT the chip address length!
3748 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
3749 EEPROM chips that implement "address overflow" are ones
3750 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
3751 address and the extra bits end up in the "chip address" bit
3752 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
3755 Note that we consider the length of the address field to
3756 still be one byte because the extra address bits are hidden
3757 in the chip address.
3759 - CONFIG_SYS_EEPROM_SIZE:
3760 The size in bytes of the EEPROM device.
3762 - CONFIG_ENV_EEPROM_IS_ON_I2C
3763 define this, if you have I2C and SPI activated, and your
3764 EEPROM, which holds the environment, is on the I2C bus.
3766 - CONFIG_I2C_ENV_EEPROM_BUS
3767 if you have an Environment on an EEPROM reached over
3768 I2C muxes, you can define here, how to reach this
3769 EEPROM. For example:
3771 #define CONFIG_I2C_ENV_EEPROM_BUS 1
3773 EEPROM which holds the environment, is reached over
3774 a pca9547 i2c mux with address 0x70, channel 3.
3776 - CONFIG_ENV_IS_IN_DATAFLASH:
3778 Define this if you have a DataFlash memory device which you
3779 want to use for the environment.
3781 - CONFIG_ENV_OFFSET:
3785 These three #defines specify the offset and size of the
3786 environment area within the total memory of your DataFlash placed
3787 at the specified address.
3789 - CONFIG_ENV_IS_IN_SPI_FLASH:
3791 Define this if you have a SPI Flash memory device which you
3792 want to use for the environment.
3794 - CONFIG_ENV_OFFSET:
3797 These two #defines specify the offset and size of the
3798 environment area within the SPI Flash. CONFIG_ENV_OFFSET must be
3799 aligned to an erase sector boundary.
3801 - CONFIG_ENV_SECT_SIZE:
3803 Define the SPI flash's sector size.
3805 - CONFIG_ENV_OFFSET_REDUND (optional):
3807 This setting describes a second storage area of CONFIG_ENV_SIZE
3808 size used to hold a redundant copy of the environment data, so
3809 that there is a valid backup copy in case there is a power failure
3810 during a "saveenv" operation. CONFIG_ENV_OFFSET_REDUND must be
3811 aligned to an erase sector boundary.
3813 - CONFIG_ENV_SPI_BUS (optional):
3814 - CONFIG_ENV_SPI_CS (optional):
3816 Define the SPI bus and chip select. If not defined they will be 0.
3818 - CONFIG_ENV_SPI_MAX_HZ (optional):
3820 Define the SPI max work clock. If not defined then use 1MHz.
3822 - CONFIG_ENV_SPI_MODE (optional):
3824 Define the SPI work mode. If not defined then use SPI_MODE_3.
3826 - CONFIG_ENV_IS_IN_REMOTE:
3828 Define this if you have a remote memory space which you
3829 want to use for the local device's environment.
3834 These two #defines specify the address and size of the
3835 environment area within the remote memory space. The
3836 local device can get the environment from remote memory
3837 space by SRIO or PCIE links.
3839 BE CAREFUL! For some special cases, the local device can not use
3840 "saveenv" command. For example, the local device will get the
3841 environment stored in a remote NOR flash by SRIO or PCIE link,
3842 but it can not erase, write this NOR flash by SRIO or PCIE interface.
3844 - CONFIG_ENV_IS_IN_NAND:
3846 Define this if you have a NAND device which you want to use
3847 for the environment.
3849 - CONFIG_ENV_OFFSET:
3852 These two #defines specify the offset and size of the environment
3853 area within the first NAND device. CONFIG_ENV_OFFSET must be
3854 aligned to an erase block boundary.
3856 - CONFIG_ENV_OFFSET_REDUND (optional):
3858 This setting describes a second storage area of CONFIG_ENV_SIZE
3859 size used to hold a redundant copy of the environment data, so
3860 that there is a valid backup copy in case there is a power failure
3861 during a "saveenv" operation. CONFIG_ENV_OFFSET_REDUND must be
3862 aligned to an erase block boundary.
3864 - CONFIG_ENV_RANGE (optional):
3866 Specifies the length of the region in which the environment
3867 can be written. This should be a multiple of the NAND device's
3868 block size. Specifying a range with more erase blocks than
3869 are needed to hold CONFIG_ENV_SIZE allows bad blocks within
3870 the range to be avoided.
3872 - CONFIG_ENV_OFFSET_OOB (optional):
3874 Enables support for dynamically retrieving the offset of the
3875 environment from block zero's out-of-band data. The
3876 "nand env.oob" command can be used to record this offset.
3877 Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
3878 using CONFIG_ENV_OFFSET_OOB.
3880 - CONFIG_NAND_ENV_DST
3882 Defines address in RAM to which the nand_spl code should copy the
3883 environment. If redundant environment is used, it will be copied to
3884 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
3886 - CONFIG_ENV_IS_IN_UBI:
3888 Define this if you have an UBI volume that you want to use for the
3889 environment. This has the benefit of wear-leveling the environment
3890 accesses, which is important on NAND.
3892 - CONFIG_ENV_UBI_PART:
3894 Define this to a string that is the mtd partition containing the UBI.
3896 - CONFIG_ENV_UBI_VOLUME:
3898 Define this to the name of the volume that you want to store the
3901 - CONFIG_ENV_UBI_VOLUME_REDUND:
3903 Define this to the name of another volume to store a second copy of
3904 the environment in. This will enable redundant environments in UBI.
3905 It is assumed that both volumes are in the same MTD partition.
3907 - CONFIG_UBI_SILENCE_MSG
3908 - CONFIG_UBIFS_SILENCE_MSG
3910 You will probably want to define these to avoid a really noisy system
3911 when storing the env in UBI.
3913 - CONFIG_ENV_IS_IN_FAT:
3914 Define this if you want to use the FAT file system for the environment.
3916 - FAT_ENV_INTERFACE:
3918 Define this to a string that is the name of the block device.
3920 - FAT_ENV_DEVICE_AND_PART:
3922 Define this to a string to specify the partition of the device. It can
3925 "D:P", "D:0", "D", "D:" or "D:auto" (D, P are integers. And P >= 1)
3926 - "D:P": device D partition P. Error occurs if device D has no
3929 - "D" or "D:": device D partition 1 if device D has partition
3930 table, or the whole device D if has no partition
3932 - "D:auto": first partition in device D with bootable flag set.
3933 If none, first valid partition in device D. If no
3934 partition table then means device D.
3938 It's a string of the FAT file name. This file use to store the
3942 This should be defined. Otherwise it cannot save the environment file.
3944 - CONFIG_ENV_IS_IN_MMC:
3946 Define this if you have an MMC device which you want to use for the
3949 - CONFIG_SYS_MMC_ENV_DEV:
3951 Specifies which MMC device the environment is stored in.
3953 - CONFIG_SYS_MMC_ENV_PART (optional):
3955 Specifies which MMC partition the environment is stored in. If not
3956 set, defaults to partition 0, the user area. Common values might be
3957 1 (first MMC boot partition), 2 (second MMC boot partition).
3959 - CONFIG_ENV_OFFSET:
3962 These two #defines specify the offset and size of the environment
3963 area within the specified MMC device.
3965 If offset is positive (the usual case), it is treated as relative to
3966 the start of the MMC partition. If offset is negative, it is treated
3967 as relative to the end of the MMC partition. This can be useful if
3968 your board may be fitted with different MMC devices, which have
3969 different sizes for the MMC partitions, and you always want the
3970 environment placed at the very end of the partition, to leave the
3971 maximum possible space before it, to store other data.
3973 These two values are in units of bytes, but must be aligned to an
3974 MMC sector boundary.
3976 - CONFIG_ENV_OFFSET_REDUND (optional):
3978 Specifies a second storage area, of CONFIG_ENV_SIZE size, used to
3979 hold a redundant copy of the environment data. This provides a
3980 valid backup copy in case the other copy is corrupted, e.g. due
3981 to a power failure during a "saveenv" operation.
3983 This value may also be positive or negative; this is handled in the
3984 same way as CONFIG_ENV_OFFSET.
3986 This value is also in units of bytes, but must also be aligned to
3987 an MMC sector boundary.
3989 - CONFIG_ENV_SIZE_REDUND (optional):
3991 This value need not be set, even when CONFIG_ENV_OFFSET_REDUND is
3992 set. If this value is set, it must be set to the same value as
3995 - CONFIG_SYS_SPI_INIT_OFFSET
3997 Defines offset to the initial SPI buffer area in DPRAM. The
3998 area is used at an early stage (ROM part) if the environment
3999 is configured to reside in the SPI EEPROM: We need a 520 byte
4000 scratch DPRAM area. It is used between the two initialization
4001 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
4002 to be a good choice since it makes it far enough from the
4003 start of the data area as well as from the stack pointer.
4005 Please note that the environment is read-only until the monitor
4006 has been relocated to RAM and a RAM copy of the environment has been
4007 created; also, when using EEPROM you will have to use getenv_f()
4008 until then to read environment variables.
4010 The environment is protected by a CRC32 checksum. Before the monitor
4011 is relocated into RAM, as a result of a bad CRC you will be working
4012 with the compiled-in default environment - *silently*!!! [This is
4013 necessary, because the first environment variable we need is the
4014 "baudrate" setting for the console - if we have a bad CRC, we don't
4015 have any device yet where we could complain.]
4017 Note: once the monitor has been relocated, then it will complain if
4018 the default environment is used; a new CRC is computed as soon as you
4019 use the "saveenv" command to store a valid environment.
4021 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
4022 Echo the inverted Ethernet link state to the fault LED.
4024 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
4025 also needs to be defined.
4027 - CONFIG_SYS_FAULT_MII_ADDR:
4028 MII address of the PHY to check for the Ethernet link state.
4030 - CONFIG_NS16550_MIN_FUNCTIONS:
4031 Define this if you desire to only have use of the NS16550_init
4032 and NS16550_putc functions for the serial driver located at
4033 drivers/serial/ns16550.c. This option is useful for saving
4034 space for already greatly restricted images, including but not
4035 limited to NAND_SPL configurations.
4037 - CONFIG_DISPLAY_BOARDINFO
4038 Display information about the board that U-Boot is running on
4039 when U-Boot starts up. The board function checkboard() is called
4042 - CONFIG_DISPLAY_BOARDINFO_LATE
4043 Similar to the previous option, but display this information
4044 later, once stdio is running and output goes to the LCD, if
4047 - CONFIG_BOARD_SIZE_LIMIT:
4048 Maximum size of the U-Boot image. When defined, the
4049 build system checks that the actual size does not
4052 Low Level (hardware related) configuration options:
4053 ---------------------------------------------------
4055 - CONFIG_SYS_CACHELINE_SIZE:
4056 Cache Line Size of the CPU.
4058 - CONFIG_SYS_DEFAULT_IMMR:
4059 Default address of the IMMR after system reset.
4061 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
4062 and RPXsuper) to be able to adjust the position of
4063 the IMMR register after a reset.
4065 - CONFIG_SYS_CCSRBAR_DEFAULT:
4066 Default (power-on reset) physical address of CCSR on Freescale
4069 - CONFIG_SYS_CCSRBAR:
4070 Virtual address of CCSR. On a 32-bit build, this is typically
4071 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
4073 CONFIG_SYS_DEFAULT_IMMR must also be set to this value,
4074 for cross-platform code that uses that macro instead.
4076 - CONFIG_SYS_CCSRBAR_PHYS:
4077 Physical address of CCSR. CCSR can be relocated to a new
4078 physical address, if desired. In this case, this macro should
4079 be set to that address. Otherwise, it should be set to the
4080 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
4081 is typically relocated on 36-bit builds. It is recommended
4082 that this macro be defined via the _HIGH and _LOW macros:
4084 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
4085 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
4087 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
4088 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
4089 either 0 (32-bit build) or 0xF (36-bit build). This macro is
4090 used in assembly code, so it must not contain typecasts or
4091 integer size suffixes (e.g. "ULL").
4093 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
4094 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
4095 used in assembly code, so it must not contain typecasts or
4096 integer size suffixes (e.g. "ULL").
4098 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
4099 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
4100 forced to a value that ensures that CCSR is not relocated.
4102 - Floppy Disk Support:
4103 CONFIG_SYS_FDC_DRIVE_NUMBER
4105 the default drive number (default value 0)
4107 CONFIG_SYS_ISA_IO_STRIDE
4109 defines the spacing between FDC chipset registers
4112 CONFIG_SYS_ISA_IO_OFFSET
4114 defines the offset of register from address. It
4115 depends on which part of the data bus is connected to
4116 the FDC chipset. (default value 0)
4118 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
4119 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
4122 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
4123 fdc_hw_init() is called at the beginning of the FDC
4124 setup. fdc_hw_init() must be provided by the board
4125 source code. It is used to make hardware-dependent
4129 Most IDE controllers were designed to be connected with PCI
4130 interface. Only few of them were designed for AHB interface.
4131 When software is doing ATA command and data transfer to
4132 IDE devices through IDE-AHB controller, some additional
4133 registers accessing to these kind of IDE-AHB controller
4136 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
4137 DO NOT CHANGE unless you know exactly what you're
4138 doing! (11-4) [MPC8xx/82xx systems only]
4140 - CONFIG_SYS_INIT_RAM_ADDR:
4142 Start address of memory area that can be used for
4143 initial data and stack; please note that this must be
4144 writable memory that is working WITHOUT special
4145 initialization, i. e. you CANNOT use normal RAM which
4146 will become available only after programming the
4147 memory controller and running certain initialization
4150 U-Boot uses the following memory types:
4151 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
4152 - MPC824X: data cache
4153 - PPC4xx: data cache
4155 - CONFIG_SYS_GBL_DATA_OFFSET:
4157 Offset of the initial data structure in the memory
4158 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
4159 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
4160 data is located at the end of the available space
4161 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
4162 GENERATED_GBL_DATA_SIZE), and the initial stack is just
4163 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
4164 CONFIG_SYS_GBL_DATA_OFFSET) downward.
4167 On the MPC824X (or other systems that use the data
4168 cache for initial memory) the address chosen for
4169 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
4170 point to an otherwise UNUSED address space between
4171 the top of RAM and the start of the PCI space.
4173 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
4175 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
4177 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
4179 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
4181 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
4183 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
4185 - CONFIG_SYS_OR_TIMING_SDRAM:
4188 - CONFIG_SYS_MAMR_PTA:
4189 periodic timer for refresh
4191 - CONFIG_SYS_DER: Debug Event Register (37-47)
4193 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
4194 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
4195 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
4196 CONFIG_SYS_BR1_PRELIM:
4197 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
4199 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
4200 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
4201 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
4202 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
4204 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
4205 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
4206 Machine Mode Register and Memory Periodic Timer
4207 Prescaler definitions (SDRAM timing)
4209 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
4210 enable I2C microcode relocation patch (MPC8xx);
4211 define relocation offset in DPRAM [DSP2]
4213 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
4214 enable SMC microcode relocation patch (MPC8xx);
4215 define relocation offset in DPRAM [SMC1]
4217 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
4218 enable SPI microcode relocation patch (MPC8xx);
4219 define relocation offset in DPRAM [SCC4]
4221 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
4222 Offset of the bootmode word in DPRAM used by post
4223 (Power On Self Tests). This definition overrides
4224 #define'd default value in commproc.h resp.
4227 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
4228 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
4229 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
4230 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
4231 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
4232 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
4233 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
4234 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
4235 Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
4237 - CONFIG_PCI_DISABLE_PCIE:
4238 Disable PCI-Express on systems where it is supported but not
4241 - CONFIG_PCI_ENUM_ONLY
4242 Only scan through and get the devices on the buses.
4243 Don't do any setup work, presumably because someone or
4244 something has already done it, and we don't need to do it
4245 a second time. Useful for platforms that are pre-booted
4246 by coreboot or similar.
4248 - CONFIG_PCI_INDIRECT_BRIDGE:
4249 Enable support for indirect PCI bridges.
4252 Chip has SRIO or not
4255 Board has SRIO 1 port available
4258 Board has SRIO 2 port available
4260 - CONFIG_SRIO_PCIE_BOOT_MASTER
4261 Board can support master function for Boot from SRIO and PCIE
4263 - CONFIG_SYS_SRIOn_MEM_VIRT:
4264 Virtual Address of SRIO port 'n' memory region
4266 - CONFIG_SYS_SRIOn_MEM_PHYS:
4267 Physical Address of SRIO port 'n' memory region
4269 - CONFIG_SYS_SRIOn_MEM_SIZE:
4270 Size of SRIO port 'n' memory region
4272 - CONFIG_SYS_NAND_BUSWIDTH_16BIT
4273 Defined to tell the NAND controller that the NAND chip is using
4275 Not all NAND drivers use this symbol.
4276 Example of drivers that use it:
4277 - drivers/mtd/nand/ndfc.c
4278 - drivers/mtd/nand/mxc_nand.c
4280 - CONFIG_SYS_NDFC_EBC0_CFG
4281 Sets the EBC0_CFG register for the NDFC. If not defined
4282 a default value will be used.
4285 Get DDR timing information from an I2C EEPROM. Common
4286 with pluggable memory modules such as SODIMMs
4289 I2C address of the SPD EEPROM
4291 - CONFIG_SYS_SPD_BUS_NUM
4292 If SPD EEPROM is on an I2C bus other than the first
4293 one, specify here. Note that the value must resolve
4294 to something your driver can deal with.
4296 - CONFIG_SYS_DDR_RAW_TIMING
4297 Get DDR timing information from other than SPD. Common with
4298 soldered DDR chips onboard without SPD. DDR raw timing
4299 parameters are extracted from datasheet and hard-coded into
4300 header files or board specific files.
4302 - CONFIG_FSL_DDR_INTERACTIVE
4303 Enable interactive DDR debugging. See doc/README.fsl-ddr.
4305 - CONFIG_FSL_DDR_SYNC_REFRESH
4306 Enable sync of refresh for multiple controllers.
4308 - CONFIG_FSL_DDR_BIST
4309 Enable built-in memory test for Freescale DDR controllers.
4311 - CONFIG_SYS_83XX_DDR_USES_CS0
4312 Only for 83xx systems. If specified, then DDR should
4313 be configured using CS0 and CS1 instead of CS2 and CS3.
4315 - CONFIG_ETHER_ON_FEC[12]
4316 Define to enable FEC[12] on a 8xx series processor.
4318 - CONFIG_FEC[12]_PHY
4319 Define to the hardcoded PHY address which corresponds
4320 to the given FEC; i. e.
4321 #define CONFIG_FEC1_PHY 4
4322 means that the PHY with address 4 is connected to FEC1
4324 When set to -1, means to probe for first available.
4326 - CONFIG_FEC[12]_PHY_NORXERR
4327 The PHY does not have a RXERR line (RMII only).
4328 (so program the FEC to ignore it).
4331 Enable RMII mode for all FECs.
4332 Note that this is a global option, we can't
4333 have one FEC in standard MII mode and another in RMII mode.
4335 - CONFIG_CRC32_VERIFY
4336 Add a verify option to the crc32 command.
4339 => crc32 -v <address> <count> <crc32>
4341 Where address/count indicate a memory area
4342 and crc32 is the correct crc32 which the
4346 Add the "loopw" memory command. This only takes effect if
4347 the memory commands are activated globally (CONFIG_CMD_MEM).
4350 Add the "mdc" and "mwc" memory commands. These are cyclic
4355 This command will print 4 bytes (10,11,12,13) each 500 ms.
4357 => mwc.l 100 12345678 10
4358 This command will write 12345678 to address 100 all 10 ms.
4360 This only takes effect if the memory commands are activated
4361 globally (CONFIG_CMD_MEM).
4363 - CONFIG_SKIP_LOWLEVEL_INIT
4364 [ARM, NDS32, MIPS only] If this variable is defined, then certain
4365 low level initializations (like setting up the memory
4366 controller) are omitted and/or U-Boot does not
4367 relocate itself into RAM.
4369 Normally this variable MUST NOT be defined. The only
4370 exception is when U-Boot is loaded (to RAM) by some
4371 other boot loader or by a debugger which performs
4372 these initializations itself.
4374 - CONFIG_SKIP_LOWLEVEL_INIT_ONLY
4375 [ARM926EJ-S only] This allows just the call to lowlevel_init()
4376 to be skipped. The normal CP15 init (such as enabling the
4377 instruction cache) is still performed.
4380 Modifies the behaviour of start.S when compiling a loader
4381 that is executed before the actual U-Boot. E.g. when
4382 compiling a NAND SPL.
4385 Modifies the behaviour of start.S when compiling a loader
4386 that is executed after the SPL and before the actual U-Boot.
4387 It is loaded by the SPL.
4389 - CONFIG_SYS_MPC85XX_NO_RESETVEC
4390 Only for 85xx systems. If this variable is specified, the section
4391 .resetvec is not kept and the section .bootpg is placed in the
4392 previous 4k of the .text section.
4394 - CONFIG_ARCH_MAP_SYSMEM
4395 Generally U-Boot (and in particular the md command) uses
4396 effective address. It is therefore not necessary to regard
4397 U-Boot address as virtual addresses that need to be translated
4398 to physical addresses. However, sandbox requires this, since
4399 it maintains its own little RAM buffer which contains all
4400 addressable memory. This option causes some memory accesses
4401 to be mapped through map_sysmem() / unmap_sysmem().
4403 - CONFIG_X86_RESET_VECTOR
4404 If defined, the x86 reset vector code is included. This is not
4405 needed when U-Boot is running from Coreboot.
4407 - CONFIG_SPL_AM33XX_ENABLE_RTC32K_OSC:
4408 Enables the RTC32K OSC on AM33xx based plattforms
4410 - CONFIG_SYS_NAND_NO_SUBPAGE_WRITE
4411 Option to disable subpage write in NAND driver
4412 driver that uses this:
4413 drivers/mtd/nand/davinci_nand.c
4415 Freescale QE/FMAN Firmware Support:
4416 -----------------------------------
4418 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
4419 loading of "firmware", which is encoded in the QE firmware binary format.
4420 This firmware often needs to be loaded during U-Boot booting, so macros
4421 are used to identify the storage device (NOR flash, SPI, etc) and the address
4424 - CONFIG_SYS_FMAN_FW_ADDR
4425 The address in the storage device where the FMAN microcode is located. The
4426 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4429 - CONFIG_SYS_QE_FW_ADDR
4430 The address in the storage device where the QE microcode is located. The
4431 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4434 - CONFIG_SYS_QE_FMAN_FW_LENGTH
4435 The maximum possible size of the firmware. The firmware binary format
4436 has a field that specifies the actual size of the firmware, but it
4437 might not be possible to read any part of the firmware unless some
4438 local storage is allocated to hold the entire firmware first.
4440 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
4441 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
4442 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
4443 virtual address in NOR flash.
4445 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
4446 Specifies that QE/FMAN firmware is located in NAND flash.
4447 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
4449 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
4450 Specifies that QE/FMAN firmware is located on the primary SD/MMC
4451 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
4453 - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
4454 Specifies that QE/FMAN firmware is located in the remote (master)
4455 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
4456 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
4457 window->master inbound window->master LAW->the ucode address in
4458 master's memory space.
4460 Freescale Layerscape Management Complex Firmware Support:
4461 ---------------------------------------------------------
4462 The Freescale Layerscape Management Complex (MC) supports the loading of
4464 This firmware often needs to be loaded during U-Boot booting, so macros
4465 are used to identify the storage device (NOR flash, SPI, etc) and the address
4468 - CONFIG_FSL_MC_ENET
4469 Enable the MC driver for Layerscape SoCs.
4471 Freescale Layerscape Debug Server Support:
4472 -------------------------------------------
4473 The Freescale Layerscape Debug Server Support supports the loading of
4474 "Debug Server firmware" and triggering SP boot-rom.
4475 This firmware often needs to be loaded during U-Boot booting.
4477 - CONFIG_SYS_MC_RSV_MEM_ALIGN
4478 Define alignment of reserved memory MC requires
4483 In order to achieve reproducible builds, timestamps used in the U-Boot build
4484 process have to be set to a fixed value.
4486 This is done using the SOURCE_DATE_EPOCH environment variable.
4487 SOURCE_DATE_EPOCH is to be set on the build host's shell, not as a configuration
4488 option for U-Boot or an environment variable in U-Boot.
4490 SOURCE_DATE_EPOCH should be set to a number of seconds since the epoch, in UTC.
4492 Building the Software:
4493 ======================
4495 Building U-Boot has been tested in several native build environments
4496 and in many different cross environments. Of course we cannot support
4497 all possibly existing versions of cross development tools in all
4498 (potentially obsolete) versions. In case of tool chain problems we
4499 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
4500 which is extensively used to build and test U-Boot.
4502 If you are not using a native environment, it is assumed that you
4503 have GNU cross compiling tools available in your path. In this case,
4504 you must set the environment variable CROSS_COMPILE in your shell.
4505 Note that no changes to the Makefile or any other source files are
4506 necessary. For example using the ELDK on a 4xx CPU, please enter:
4508 $ CROSS_COMPILE=ppc_4xx-
4509 $ export CROSS_COMPILE
4511 Note: If you wish to generate Windows versions of the utilities in
4512 the tools directory you can use the MinGW toolchain
4513 (http://www.mingw.org). Set your HOST tools to the MinGW
4514 toolchain and execute 'make tools'. For example:
4516 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
4518 Binaries such as tools/mkimage.exe will be created which can
4519 be executed on computers running Windows.
4521 U-Boot is intended to be simple to build. After installing the
4522 sources you must configure U-Boot for one specific board type. This
4527 where "NAME_defconfig" is the name of one of the existing configu-
4528 rations; see boards.cfg for supported names.
4530 Note: for some board special configuration names may exist; check if
4531 additional information is available from the board vendor; for
4532 instance, the TQM823L systems are available without (standard)
4533 or with LCD support. You can select such additional "features"
4534 when choosing the configuration, i. e.
4536 make TQM823L_defconfig
4537 - will configure for a plain TQM823L, i. e. no LCD support
4539 make TQM823L_LCD_defconfig
4540 - will configure for a TQM823L with U-Boot console on LCD
4545 Finally, type "make all", and you should get some working U-Boot
4546 images ready for download to / installation on your system:
4548 - "u-boot.bin" is a raw binary image
4549 - "u-boot" is an image in ELF binary format
4550 - "u-boot.srec" is in Motorola S-Record format
4552 By default the build is performed locally and the objects are saved
4553 in the source directory. One of the two methods can be used to change
4554 this behavior and build U-Boot to some external directory:
4556 1. Add O= to the make command line invocations:
4558 make O=/tmp/build distclean
4559 make O=/tmp/build NAME_defconfig
4560 make O=/tmp/build all
4562 2. Set environment variable KBUILD_OUTPUT to point to the desired location:
4564 export KBUILD_OUTPUT=/tmp/build
4569 Note that the command line "O=" setting overrides the KBUILD_OUTPUT environment
4573 Please be aware that the Makefiles assume you are using GNU make, so
4574 for instance on NetBSD you might need to use "gmake" instead of
4578 If the system board that you have is not listed, then you will need
4579 to port U-Boot to your hardware platform. To do this, follow these
4582 1. Create a new directory to hold your board specific code. Add any
4583 files you need. In your board directory, you will need at least
4584 the "Makefile" and a "<board>.c".
4585 2. Create a new configuration file "include/configs/<board>.h" for
4587 3. If you're porting U-Boot to a new CPU, then also create a new
4588 directory to hold your CPU specific code. Add any files you need.
4589 4. Run "make <board>_defconfig" with your new name.
4590 5. Type "make", and you should get a working "u-boot.srec" file
4591 to be installed on your target system.
4592 6. Debug and solve any problems that might arise.
4593 [Of course, this last step is much harder than it sounds.]
4596 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
4597 ==============================================================
4599 If you have modified U-Boot sources (for instance added a new board
4600 or support for new devices, a new CPU, etc.) you are expected to
4601 provide feedback to the other developers. The feedback normally takes
4602 the form of a "patch", i. e. a context diff against a certain (latest
4603 official or latest in the git repository) version of U-Boot sources.
4605 But before you submit such a patch, please verify that your modifi-
4606 cation did not break existing code. At least make sure that *ALL* of
4607 the supported boards compile WITHOUT ANY compiler warnings. To do so,
4608 just run the buildman script (tools/buildman/buildman), which will
4609 configure and build U-Boot for ALL supported system. Be warned, this
4610 will take a while. Please see the buildman README, or run 'buildman -H'
4614 See also "U-Boot Porting Guide" below.
4617 Monitor Commands - Overview:
4618 ============================
4620 go - start application at address 'addr'
4621 run - run commands in an environment variable
4622 bootm - boot application image from memory
4623 bootp - boot image via network using BootP/TFTP protocol
4624 bootz - boot zImage from memory
4625 tftpboot- boot image via network using TFTP protocol
4626 and env variables "ipaddr" and "serverip"
4627 (and eventually "gatewayip")
4628 tftpput - upload a file via network using TFTP protocol
4629 rarpboot- boot image via network using RARP/TFTP protocol
4630 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
4631 loads - load S-Record file over serial line
4632 loadb - load binary file over serial line (kermit mode)
4634 mm - memory modify (auto-incrementing)
4635 nm - memory modify (constant address)
4636 mw - memory write (fill)
4638 cmp - memory compare
4639 crc32 - checksum calculation
4640 i2c - I2C sub-system
4641 sspi - SPI utility commands
4642 base - print or set address offset
4643 printenv- print environment variables
4644 setenv - set environment variables
4645 saveenv - save environment variables to persistent storage
4646 protect - enable or disable FLASH write protection
4647 erase - erase FLASH memory
4648 flinfo - print FLASH memory information
4649 nand - NAND memory operations (see doc/README.nand)
4650 bdinfo - print Board Info structure
4651 iminfo - print header information for application image
4652 coninfo - print console devices and informations
4653 ide - IDE sub-system
4654 loop - infinite loop on address range
4655 loopw - infinite write loop on address range
4656 mtest - simple RAM test
4657 icache - enable or disable instruction cache
4658 dcache - enable or disable data cache
4659 reset - Perform RESET of the CPU
4660 echo - echo args to console
4661 version - print monitor version
4662 help - print online help
4663 ? - alias for 'help'
4666 Monitor Commands - Detailed Description:
4667 ========================================
4671 For now: just type "help <command>".
4674 Environment Variables:
4675 ======================
4677 U-Boot supports user configuration using Environment Variables which
4678 can be made persistent by saving to Flash memory.
4680 Environment Variables are set using "setenv", printed using
4681 "printenv", and saved to Flash using "saveenv". Using "setenv"
4682 without a value can be used to delete a variable from the
4683 environment. As long as you don't save the environment you are
4684 working with an in-memory copy. In case the Flash area containing the
4685 environment is erased by accident, a default environment is provided.
4687 Some configuration options can be set using Environment Variables.
4689 List of environment variables (most likely not complete):
4691 baudrate - see CONFIG_BAUDRATE
4693 bootdelay - see CONFIG_BOOTDELAY
4695 bootcmd - see CONFIG_BOOTCOMMAND
4697 bootargs - Boot arguments when booting an RTOS image
4699 bootfile - Name of the image to load with TFTP
4701 bootm_low - Memory range available for image processing in the bootm
4702 command can be restricted. This variable is given as
4703 a hexadecimal number and defines lowest address allowed
4704 for use by the bootm command. See also "bootm_size"
4705 environment variable. Address defined by "bootm_low" is
4706 also the base of the initial memory mapping for the Linux
4707 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
4710 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
4711 This variable is given as a hexadecimal number and it
4712 defines the size of the memory region starting at base
4713 address bootm_low that is accessible by the Linux kernel
4714 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
4715 as the default value if it is defined, and bootm_size is
4718 bootm_size - Memory range available for image processing in the bootm
4719 command can be restricted. This variable is given as
4720 a hexadecimal number and defines the size of the region
4721 allowed for use by the bootm command. See also "bootm_low"
4722 environment variable.
4724 updatefile - Location of the software update file on a TFTP server, used
4725 by the automatic software update feature. Please refer to
4726 documentation in doc/README.update for more details.
4728 autoload - if set to "no" (any string beginning with 'n'),
4729 "bootp" will just load perform a lookup of the
4730 configuration from the BOOTP server, but not try to
4731 load any image using TFTP
4733 autostart - if set to "yes", an image loaded using the "bootp",
4734 "rarpboot", "tftpboot" or "diskboot" commands will
4735 be automatically started (by internally calling
4738 If set to "no", a standalone image passed to the
4739 "bootm" command will be copied to the load address
4740 (and eventually uncompressed), but NOT be started.
4741 This can be used to load and uncompress arbitrary
4744 fdt_high - if set this restricts the maximum address that the
4745 flattened device tree will be copied into upon boot.
4746 For example, if you have a system with 1 GB memory
4747 at physical address 0x10000000, while Linux kernel
4748 only recognizes the first 704 MB as low memory, you
4749 may need to set fdt_high as 0x3C000000 to have the
4750 device tree blob be copied to the maximum address
4751 of the 704 MB low memory, so that Linux kernel can
4752 access it during the boot procedure.
4754 If this is set to the special value 0xFFFFFFFF then
4755 the fdt will not be copied at all on boot. For this
4756 to work it must reside in writable memory, have
4757 sufficient padding on the end of it for u-boot to
4758 add the information it needs into it, and the memory
4759 must be accessible by the kernel.
4761 fdtcontroladdr- if set this is the address of the control flattened
4762 device tree used by U-Boot when CONFIG_OF_CONTROL is
4765 i2cfast - (PPC405GP|PPC405EP only)
4766 if set to 'y' configures Linux I2C driver for fast
4767 mode (400kHZ). This environment variable is used in
4768 initialization code. So, for changes to be effective
4769 it must be saved and board must be reset.
4771 initrd_high - restrict positioning of initrd images:
4772 If this variable is not set, initrd images will be
4773 copied to the highest possible address in RAM; this
4774 is usually what you want since it allows for
4775 maximum initrd size. If for some reason you want to
4776 make sure that the initrd image is loaded below the
4777 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
4778 variable to a value of "no" or "off" or "0".
4779 Alternatively, you can set it to a maximum upper
4780 address to use (U-Boot will still check that it
4781 does not overwrite the U-Boot stack and data).
4783 For instance, when you have a system with 16 MB
4784 RAM, and want to reserve 4 MB from use by Linux,
4785 you can do this by adding "mem=12M" to the value of
4786 the "bootargs" variable. However, now you must make
4787 sure that the initrd image is placed in the first
4788 12 MB as well - this can be done with
4790 setenv initrd_high 00c00000
4792 If you set initrd_high to 0xFFFFFFFF, this is an
4793 indication to U-Boot that all addresses are legal
4794 for the Linux kernel, including addresses in flash
4795 memory. In this case U-Boot will NOT COPY the
4796 ramdisk at all. This may be useful to reduce the
4797 boot time on your system, but requires that this
4798 feature is supported by your Linux kernel.
4800 ipaddr - IP address; needed for tftpboot command
4802 loadaddr - Default load address for commands like "bootp",
4803 "rarpboot", "tftpboot", "loadb" or "diskboot"
4805 loads_echo - see CONFIG_LOADS_ECHO
4807 serverip - TFTP server IP address; needed for tftpboot command
4809 bootretry - see CONFIG_BOOT_RETRY_TIME
4811 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
4813 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
4815 ethprime - controls which interface is used first.
4817 ethact - controls which interface is currently active.
4818 For example you can do the following
4820 => setenv ethact FEC
4821 => ping 192.168.0.1 # traffic sent on FEC
4822 => setenv ethact SCC
4823 => ping 10.0.0.1 # traffic sent on SCC
4825 ethrotate - When set to "no" U-Boot does not go through all
4826 available network interfaces.
4827 It just stays at the currently selected interface.
4829 netretry - When set to "no" each network operation will
4830 either succeed or fail without retrying.
4831 When set to "once" the network operation will
4832 fail when all the available network interfaces
4833 are tried once without success.
4834 Useful on scripts which control the retry operation
4837 npe_ucode - set load address for the NPE microcode
4839 silent_linux - If set then Linux will be told to boot silently, by
4840 changing the console to be empty. If "yes" it will be
4841 made silent. If "no" it will not be made silent. If
4842 unset, then it will be made silent if the U-Boot console
4845 tftpsrcp - If this is set, the value is used for TFTP's
4848 tftpdstp - If this is set, the value is used for TFTP's UDP
4849 destination port instead of the Well Know Port 69.
4851 tftpblocksize - Block size to use for TFTP transfers; if not set,
4852 we use the TFTP server's default block size
4854 tftptimeout - Retransmission timeout for TFTP packets (in milli-
4855 seconds, minimum value is 1000 = 1 second). Defines
4856 when a packet is considered to be lost so it has to
4857 be retransmitted. The default is 5000 = 5 seconds.
4858 Lowering this value may make downloads succeed
4859 faster in networks with high packet loss rates or
4860 with unreliable TFTP servers.
4862 tftptimeoutcountmax - maximum count of TFTP timeouts (no
4863 unit, minimum value = 0). Defines how many timeouts
4864 can happen during a single file transfer before that
4865 transfer is aborted. The default is 10, and 0 means
4866 'no timeouts allowed'. Increasing this value may help
4867 downloads succeed with high packet loss rates, or with
4868 unreliable TFTP servers or client hardware.
4870 vlan - When set to a value < 4095 the traffic over
4871 Ethernet is encapsulated/received over 802.1q
4874 bootpretryperiod - Period during which BOOTP/DHCP sends retries.
4875 Unsigned value, in milliseconds. If not set, the period will
4876 be either the default (28000), or a value based on
4877 CONFIG_NET_RETRY_COUNT, if defined. This value has
4878 precedence over the valu based on CONFIG_NET_RETRY_COUNT.
4880 The following image location variables contain the location of images
4881 used in booting. The "Image" column gives the role of the image and is
4882 not an environment variable name. The other columns are environment
4883 variable names. "File Name" gives the name of the file on a TFTP
4884 server, "RAM Address" gives the location in RAM the image will be
4885 loaded to, and "Flash Location" gives the image's address in NOR
4886 flash or offset in NAND flash.
4888 *Note* - these variables don't have to be defined for all boards, some
4889 boards currently use other variables for these purposes, and some
4890 boards use these variables for other purposes.
4892 Image File Name RAM Address Flash Location
4893 ----- --------- ----------- --------------
4894 u-boot u-boot u-boot_addr_r u-boot_addr
4895 Linux kernel bootfile kernel_addr_r kernel_addr
4896 device tree blob fdtfile fdt_addr_r fdt_addr
4897 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
4899 The following environment variables may be used and automatically
4900 updated by the network boot commands ("bootp" and "rarpboot"),
4901 depending the information provided by your boot server:
4903 bootfile - see above
4904 dnsip - IP address of your Domain Name Server
4905 dnsip2 - IP address of your secondary Domain Name Server
4906 gatewayip - IP address of the Gateway (Router) to use
4907 hostname - Target hostname
4909 netmask - Subnet Mask
4910 rootpath - Pathname of the root filesystem on the NFS server
4911 serverip - see above
4914 There are two special Environment Variables:
4916 serial# - contains hardware identification information such
4917 as type string and/or serial number
4918 ethaddr - Ethernet address
4920 These variables can be set only once (usually during manufacturing of
4921 the board). U-Boot refuses to delete or overwrite these variables
4922 once they have been set once.
4925 Further special Environment Variables:
4927 ver - Contains the U-Boot version string as printed
4928 with the "version" command. This variable is
4929 readonly (see CONFIG_VERSION_VARIABLE).
4932 Please note that changes to some configuration parameters may take
4933 only effect after the next boot (yes, that's just like Windoze :-).
4936 Callback functions for environment variables:
4937 ---------------------------------------------
4939 For some environment variables, the behavior of u-boot needs to change
4940 when their values are changed. This functionality allows functions to
4941 be associated with arbitrary variables. On creation, overwrite, or
4942 deletion, the callback will provide the opportunity for some side
4943 effect to happen or for the change to be rejected.
4945 The callbacks are named and associated with a function using the
4946 U_BOOT_ENV_CALLBACK macro in your board or driver code.
4948 These callbacks are associated with variables in one of two ways. The
4949 static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC
4950 in the board configuration to a string that defines a list of
4951 associations. The list must be in the following format:
4953 entry = variable_name[:callback_name]
4956 If the callback name is not specified, then the callback is deleted.
4957 Spaces are also allowed anywhere in the list.
4959 Callbacks can also be associated by defining the ".callbacks" variable
4960 with the same list format above. Any association in ".callbacks" will
4961 override any association in the static list. You can define
4962 CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the
4963 ".callbacks" environment variable in the default or embedded environment.
4965 If CONFIG_REGEX is defined, the variable_name above is evaluated as a
4966 regular expression. This allows multiple variables to be connected to
4967 the same callback without explicitly listing them all out.
4970 Command Line Parsing:
4971 =====================
4973 There are two different command line parsers available with U-Boot:
4974 the old "simple" one, and the much more powerful "hush" shell:
4976 Old, simple command line parser:
4977 --------------------------------
4979 - supports environment variables (through setenv / saveenv commands)
4980 - several commands on one line, separated by ';'
4981 - variable substitution using "... ${name} ..." syntax
4982 - special characters ('$', ';') can be escaped by prefixing with '\',
4984 setenv bootcmd bootm \${address}
4985 - You can also escape text by enclosing in single apostrophes, for example:
4986 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
4991 - similar to Bourne shell, with control structures like
4992 if...then...else...fi, for...do...done; while...do...done,
4993 until...do...done, ...
4994 - supports environment ("global") variables (through setenv / saveenv
4995 commands) and local shell variables (through standard shell syntax
4996 "name=value"); only environment variables can be used with "run"
5002 (1) If a command line (or an environment variable executed by a "run"
5003 command) contains several commands separated by semicolon, and
5004 one of these commands fails, then the remaining commands will be
5007 (2) If you execute several variables with one call to run (i. e.
5008 calling run with a list of variables as arguments), any failing
5009 command will cause "run" to terminate, i. e. the remaining
5010 variables are not executed.
5012 Note for Redundant Ethernet Interfaces:
5013 =======================================
5015 Some boards come with redundant Ethernet interfaces; U-Boot supports
5016 such configurations and is capable of automatic selection of a
5017 "working" interface when needed. MAC assignment works as follows:
5019 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
5020 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
5021 "eth1addr" (=>eth1), "eth2addr", ...
5023 If the network interface stores some valid MAC address (for instance
5024 in SROM), this is used as default address if there is NO correspon-
5025 ding setting in the environment; if the corresponding environment
5026 variable is set, this overrides the settings in the card; that means:
5028 o If the SROM has a valid MAC address, and there is no address in the
5029 environment, the SROM's address is used.
5031 o If there is no valid address in the SROM, and a definition in the
5032 environment exists, then the value from the environment variable is
5035 o If both the SROM and the environment contain a MAC address, and
5036 both addresses are the same, this MAC address is used.
5038 o If both the SROM and the environment contain a MAC address, and the
5039 addresses differ, the value from the environment is used and a
5042 o If neither SROM nor the environment contain a MAC address, an error
5043 is raised. If CONFIG_NET_RANDOM_ETHADDR is defined, then in this case
5044 a random, locally-assigned MAC is used.
5046 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
5047 will be programmed into hardware as part of the initialization process. This
5048 may be skipped by setting the appropriate 'ethmacskip' environment variable.
5049 The naming convention is as follows:
5050 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
5055 U-Boot is capable of booting (and performing other auxiliary operations on)
5056 images in two formats:
5058 New uImage format (FIT)
5059 -----------------------
5061 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
5062 to Flattened Device Tree). It allows the use of images with multiple
5063 components (several kernels, ramdisks, etc.), with contents protected by
5064 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
5070 Old image format is based on binary files which can be basically anything,
5071 preceded by a special header; see the definitions in include/image.h for
5072 details; basically, the header defines the following image properties:
5074 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
5075 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
5076 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
5077 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
5079 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
5080 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
5081 Currently supported: ARM, AVR32, Intel x86, MIPS, NDS32, Nios II, PowerPC).
5082 * Compression Type (uncompressed, gzip, bzip2)
5088 The header is marked by a special Magic Number, and both the header
5089 and the data portions of the image are secured against corruption by
5096 Although U-Boot should support any OS or standalone application
5097 easily, the main focus has always been on Linux during the design of
5100 U-Boot includes many features that so far have been part of some
5101 special "boot loader" code within the Linux kernel. Also, any
5102 "initrd" images to be used are no longer part of one big Linux image;
5103 instead, kernel and "initrd" are separate images. This implementation
5104 serves several purposes:
5106 - the same features can be used for other OS or standalone
5107 applications (for instance: using compressed images to reduce the
5108 Flash memory footprint)
5110 - it becomes much easier to port new Linux kernel versions because
5111 lots of low-level, hardware dependent stuff are done by U-Boot
5113 - the same Linux kernel image can now be used with different "initrd"
5114 images; of course this also means that different kernel images can
5115 be run with the same "initrd". This makes testing easier (you don't
5116 have to build a new "zImage.initrd" Linux image when you just
5117 change a file in your "initrd"). Also, a field-upgrade of the
5118 software is easier now.
5124 Porting Linux to U-Boot based systems:
5125 ---------------------------------------
5127 U-Boot cannot save you from doing all the necessary modifications to
5128 configure the Linux device drivers for use with your target hardware
5129 (no, we don't intend to provide a full virtual machine interface to
5132 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
5134 Just make sure your machine specific header file (for instance
5135 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
5136 Information structure as we define in include/asm-<arch>/u-boot.h,
5137 and make sure that your definition of IMAP_ADDR uses the same value
5138 as your U-Boot configuration in CONFIG_SYS_IMMR.
5140 Note that U-Boot now has a driver model, a unified model for drivers.
5141 If you are adding a new driver, plumb it into driver model. If there
5142 is no uclass available, you are encouraged to create one. See
5146 Configuring the Linux kernel:
5147 -----------------------------
5149 No specific requirements for U-Boot. Make sure you have some root
5150 device (initial ramdisk, NFS) for your target system.
5153 Building a Linux Image:
5154 -----------------------
5156 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
5157 not used. If you use recent kernel source, a new build target
5158 "uImage" will exist which automatically builds an image usable by
5159 U-Boot. Most older kernels also have support for a "pImage" target,
5160 which was introduced for our predecessor project PPCBoot and uses a
5161 100% compatible format.
5165 make TQM850L_defconfig
5170 The "uImage" build target uses a special tool (in 'tools/mkimage') to
5171 encapsulate a compressed Linux kernel image with header information,
5172 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
5174 * build a standard "vmlinux" kernel image (in ELF binary format):
5176 * convert the kernel into a raw binary image:
5178 ${CROSS_COMPILE}-objcopy -O binary \
5179 -R .note -R .comment \
5180 -S vmlinux linux.bin
5182 * compress the binary image:
5186 * package compressed binary image for U-Boot:
5188 mkimage -A ppc -O linux -T kernel -C gzip \
5189 -a 0 -e 0 -n "Linux Kernel Image" \
5190 -d linux.bin.gz uImage
5193 The "mkimage" tool can also be used to create ramdisk images for use
5194 with U-Boot, either separated from the Linux kernel image, or
5195 combined into one file. "mkimage" encapsulates the images with a 64
5196 byte header containing information about target architecture,
5197 operating system, image type, compression method, entry points, time
5198 stamp, CRC32 checksums, etc.
5200 "mkimage" can be called in two ways: to verify existing images and
5201 print the header information, or to build new images.
5203 In the first form (with "-l" option) mkimage lists the information
5204 contained in the header of an existing U-Boot image; this includes
5205 checksum verification:
5207 tools/mkimage -l image
5208 -l ==> list image header information
5210 The second form (with "-d" option) is used to build a U-Boot image
5211 from a "data file" which is used as image payload:
5213 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
5214 -n name -d data_file image
5215 -A ==> set architecture to 'arch'
5216 -O ==> set operating system to 'os'
5217 -T ==> set image type to 'type'
5218 -C ==> set compression type 'comp'
5219 -a ==> set load address to 'addr' (hex)
5220 -e ==> set entry point to 'ep' (hex)
5221 -n ==> set image name to 'name'
5222 -d ==> use image data from 'datafile'
5224 Right now, all Linux kernels for PowerPC systems use the same load
5225 address (0x00000000), but the entry point address depends on the
5228 - 2.2.x kernels have the entry point at 0x0000000C,
5229 - 2.3.x and later kernels have the entry point at 0x00000000.
5231 So a typical call to build a U-Boot image would read:
5233 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5234 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
5235 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
5236 > examples/uImage.TQM850L
5237 Image Name: 2.4.4 kernel for TQM850L
5238 Created: Wed Jul 19 02:34:59 2000
5239 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5240 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5241 Load Address: 0x00000000
5242 Entry Point: 0x00000000
5244 To verify the contents of the image (or check for corruption):
5246 -> tools/mkimage -l examples/uImage.TQM850L
5247 Image Name: 2.4.4 kernel for TQM850L
5248 Created: Wed Jul 19 02:34:59 2000
5249 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5250 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5251 Load Address: 0x00000000
5252 Entry Point: 0x00000000
5254 NOTE: for embedded systems where boot time is critical you can trade
5255 speed for memory and install an UNCOMPRESSED image instead: this
5256 needs more space in Flash, but boots much faster since it does not
5257 need to be uncompressed:
5259 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
5260 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5261 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
5262 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
5263 > examples/uImage.TQM850L-uncompressed
5264 Image Name: 2.4.4 kernel for TQM850L
5265 Created: Wed Jul 19 02:34:59 2000
5266 Image Type: PowerPC Linux Kernel Image (uncompressed)
5267 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
5268 Load Address: 0x00000000
5269 Entry Point: 0x00000000
5272 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
5273 when your kernel is intended to use an initial ramdisk:
5275 -> tools/mkimage -n 'Simple Ramdisk Image' \
5276 > -A ppc -O linux -T ramdisk -C gzip \
5277 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
5278 Image Name: Simple Ramdisk Image
5279 Created: Wed Jan 12 14:01:50 2000
5280 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5281 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
5282 Load Address: 0x00000000
5283 Entry Point: 0x00000000
5285 The "dumpimage" is a tool to disassemble images built by mkimage. Its "-i"
5286 option performs the converse operation of the mkimage's second form (the "-d"
5287 option). Given an image built by mkimage, the dumpimage extracts a "data file"
5290 tools/dumpimage -i image -T type -p position data_file
5291 -i ==> extract from the 'image' a specific 'data_file'
5292 -T ==> set image type to 'type'
5293 -p ==> 'position' (starting at 0) of the 'data_file' inside the 'image'
5296 Installing a Linux Image:
5297 -------------------------
5299 To downloading a U-Boot image over the serial (console) interface,
5300 you must convert the image to S-Record format:
5302 objcopy -I binary -O srec examples/image examples/image.srec
5304 The 'objcopy' does not understand the information in the U-Boot
5305 image header, so the resulting S-Record file will be relative to
5306 address 0x00000000. To load it to a given address, you need to
5307 specify the target address as 'offset' parameter with the 'loads'
5310 Example: install the image to address 0x40100000 (which on the
5311 TQM8xxL is in the first Flash bank):
5313 => erase 40100000 401FFFFF
5319 ## Ready for S-Record download ...
5320 ~>examples/image.srec
5321 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
5323 15989 15990 15991 15992
5324 [file transfer complete]
5326 ## Start Addr = 0x00000000
5329 You can check the success of the download using the 'iminfo' command;
5330 this includes a checksum verification so you can be sure no data
5331 corruption happened:
5335 ## Checking Image at 40100000 ...
5336 Image Name: 2.2.13 for initrd on TQM850L
5337 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5338 Data Size: 335725 Bytes = 327 kB = 0 MB
5339 Load Address: 00000000
5340 Entry Point: 0000000c
5341 Verifying Checksum ... OK
5347 The "bootm" command is used to boot an application that is stored in
5348 memory (RAM or Flash). In case of a Linux kernel image, the contents
5349 of the "bootargs" environment variable is passed to the kernel as
5350 parameters. You can check and modify this variable using the
5351 "printenv" and "setenv" commands:
5354 => printenv bootargs
5355 bootargs=root=/dev/ram
5357 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5359 => printenv bootargs
5360 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5363 ## Booting Linux kernel at 40020000 ...
5364 Image Name: 2.2.13 for NFS on TQM850L
5365 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5366 Data Size: 381681 Bytes = 372 kB = 0 MB
5367 Load Address: 00000000
5368 Entry Point: 0000000c
5369 Verifying Checksum ... OK
5370 Uncompressing Kernel Image ... OK
5371 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
5372 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5373 time_init: decrementer frequency = 187500000/60
5374 Calibrating delay loop... 49.77 BogoMIPS
5375 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
5378 If you want to boot a Linux kernel with initial RAM disk, you pass
5379 the memory addresses of both the kernel and the initrd image (PPBCOOT
5380 format!) to the "bootm" command:
5382 => imi 40100000 40200000
5384 ## Checking Image at 40100000 ...
5385 Image Name: 2.2.13 for initrd on TQM850L
5386 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5387 Data Size: 335725 Bytes = 327 kB = 0 MB
5388 Load Address: 00000000
5389 Entry Point: 0000000c
5390 Verifying Checksum ... OK
5392 ## Checking Image at 40200000 ...
5393 Image Name: Simple Ramdisk Image
5394 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5395 Data Size: 566530 Bytes = 553 kB = 0 MB
5396 Load Address: 00000000
5397 Entry Point: 00000000
5398 Verifying Checksum ... OK
5400 => bootm 40100000 40200000
5401 ## Booting Linux kernel at 40100000 ...
5402 Image Name: 2.2.13 for initrd on TQM850L
5403 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5404 Data Size: 335725 Bytes = 327 kB = 0 MB
5405 Load Address: 00000000
5406 Entry Point: 0000000c
5407 Verifying Checksum ... OK
5408 Uncompressing Kernel Image ... OK
5409 ## Loading RAMDisk Image at 40200000 ...
5410 Image Name: Simple Ramdisk Image
5411 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5412 Data Size: 566530 Bytes = 553 kB = 0 MB
5413 Load Address: 00000000
5414 Entry Point: 00000000
5415 Verifying Checksum ... OK
5416 Loading Ramdisk ... OK
5417 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
5418 Boot arguments: root=/dev/ram
5419 time_init: decrementer frequency = 187500000/60
5420 Calibrating delay loop... 49.77 BogoMIPS
5422 RAMDISK: Compressed image found at block 0
5423 VFS: Mounted root (ext2 filesystem).
5427 Boot Linux and pass a flat device tree:
5430 First, U-Boot must be compiled with the appropriate defines. See the section
5431 titled "Linux Kernel Interface" above for a more in depth explanation. The
5432 following is an example of how to start a kernel and pass an updated
5438 oft=oftrees/mpc8540ads.dtb
5439 => tftp $oftaddr $oft
5440 Speed: 1000, full duplex
5442 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
5443 Filename 'oftrees/mpc8540ads.dtb'.
5444 Load address: 0x300000
5447 Bytes transferred = 4106 (100a hex)
5448 => tftp $loadaddr $bootfile
5449 Speed: 1000, full duplex
5451 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
5453 Load address: 0x200000
5454 Loading:############
5456 Bytes transferred = 1029407 (fb51f hex)
5461 => bootm $loadaddr - $oftaddr
5462 ## Booting image at 00200000 ...
5463 Image Name: Linux-2.6.17-dirty
5464 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5465 Data Size: 1029343 Bytes = 1005.2 kB
5466 Load Address: 00000000
5467 Entry Point: 00000000
5468 Verifying Checksum ... OK
5469 Uncompressing Kernel Image ... OK
5470 Booting using flat device tree at 0x300000
5471 Using MPC85xx ADS machine description
5472 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
5476 More About U-Boot Image Types:
5477 ------------------------------
5479 U-Boot supports the following image types:
5481 "Standalone Programs" are directly runnable in the environment
5482 provided by U-Boot; it is expected that (if they behave
5483 well) you can continue to work in U-Boot after return from
5484 the Standalone Program.
5485 "OS Kernel Images" are usually images of some Embedded OS which
5486 will take over control completely. Usually these programs
5487 will install their own set of exception handlers, device
5488 drivers, set up the MMU, etc. - this means, that you cannot
5489 expect to re-enter U-Boot except by resetting the CPU.
5490 "RAMDisk Images" are more or less just data blocks, and their
5491 parameters (address, size) are passed to an OS kernel that is
5493 "Multi-File Images" contain several images, typically an OS
5494 (Linux) kernel image and one or more data images like
5495 RAMDisks. This construct is useful for instance when you want
5496 to boot over the network using BOOTP etc., where the boot
5497 server provides just a single image file, but you want to get
5498 for instance an OS kernel and a RAMDisk image.
5500 "Multi-File Images" start with a list of image sizes, each
5501 image size (in bytes) specified by an "uint32_t" in network
5502 byte order. This list is terminated by an "(uint32_t)0".
5503 Immediately after the terminating 0 follow the images, one by
5504 one, all aligned on "uint32_t" boundaries (size rounded up to
5505 a multiple of 4 bytes).
5507 "Firmware Images" are binary images containing firmware (like
5508 U-Boot or FPGA images) which usually will be programmed to
5511 "Script files" are command sequences that will be executed by
5512 U-Boot's command interpreter; this feature is especially
5513 useful when you configure U-Boot to use a real shell (hush)
5514 as command interpreter.
5516 Booting the Linux zImage:
5517 -------------------------
5519 On some platforms, it's possible to boot Linux zImage. This is done
5520 using the "bootz" command. The syntax of "bootz" command is the same
5521 as the syntax of "bootm" command.
5523 Note, defining the CONFIG_SUPPORT_RAW_INITRD allows user to supply
5524 kernel with raw initrd images. The syntax is slightly different, the
5525 address of the initrd must be augmented by it's size, in the following
5526 format: "<initrd addres>:<initrd size>".
5532 One of the features of U-Boot is that you can dynamically load and
5533 run "standalone" applications, which can use some resources of
5534 U-Boot like console I/O functions or interrupt services.
5536 Two simple examples are included with the sources:
5541 'examples/hello_world.c' contains a small "Hello World" Demo
5542 application; it is automatically compiled when you build U-Boot.
5543 It's configured to run at address 0x00040004, so you can play with it
5547 ## Ready for S-Record download ...
5548 ~>examples/hello_world.srec
5549 1 2 3 4 5 6 7 8 9 10 11 ...
5550 [file transfer complete]
5552 ## Start Addr = 0x00040004
5554 => go 40004 Hello World! This is a test.
5555 ## Starting application at 0x00040004 ...
5566 Hit any key to exit ...
5568 ## Application terminated, rc = 0x0
5570 Another example, which demonstrates how to register a CPM interrupt
5571 handler with the U-Boot code, can be found in 'examples/timer.c'.
5572 Here, a CPM timer is set up to generate an interrupt every second.
5573 The interrupt service routine is trivial, just printing a '.'
5574 character, but this is just a demo program. The application can be
5575 controlled by the following keys:
5577 ? - print current values og the CPM Timer registers
5578 b - enable interrupts and start timer
5579 e - stop timer and disable interrupts
5580 q - quit application
5583 ## Ready for S-Record download ...
5584 ~>examples/timer.srec
5585 1 2 3 4 5 6 7 8 9 10 11 ...
5586 [file transfer complete]
5588 ## Start Addr = 0x00040004
5591 ## Starting application at 0x00040004 ...
5594 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
5597 [q, b, e, ?] Set interval 1000000 us
5600 [q, b, e, ?] ........
5601 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
5604 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
5607 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
5610 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
5612 [q, b, e, ?] ...Stopping timer
5614 [q, b, e, ?] ## Application terminated, rc = 0x0
5620 Over time, many people have reported problems when trying to use the
5621 "minicom" terminal emulation program for serial download. I (wd)
5622 consider minicom to be broken, and recommend not to use it. Under
5623 Unix, I recommend to use C-Kermit for general purpose use (and
5624 especially for kermit binary protocol download ("loadb" command), and
5625 use "cu" for S-Record download ("loads" command). See
5626 http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
5627 for help with kermit.
5630 Nevertheless, if you absolutely want to use it try adding this
5631 configuration to your "File transfer protocols" section:
5633 Name Program Name U/D FullScr IO-Red. Multi
5634 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
5635 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
5641 Starting at version 0.9.2, U-Boot supports NetBSD both as host
5642 (build U-Boot) and target system (boots NetBSD/mpc8xx).
5644 Building requires a cross environment; it is known to work on
5645 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
5646 need gmake since the Makefiles are not compatible with BSD make).
5647 Note that the cross-powerpc package does not install include files;
5648 attempting to build U-Boot will fail because <machine/ansi.h> is
5649 missing. This file has to be installed and patched manually:
5651 # cd /usr/pkg/cross/powerpc-netbsd/include
5653 # ln -s powerpc machine
5654 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
5655 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
5657 Native builds *don't* work due to incompatibilities between native
5658 and U-Boot include files.
5660 Booting assumes that (the first part of) the image booted is a
5661 stage-2 loader which in turn loads and then invokes the kernel
5662 proper. Loader sources will eventually appear in the NetBSD source
5663 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
5664 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
5667 Implementation Internals:
5668 =========================
5670 The following is not intended to be a complete description of every
5671 implementation detail. However, it should help to understand the
5672 inner workings of U-Boot and make it easier to port it to custom
5676 Initial Stack, Global Data:
5677 ---------------------------
5679 The implementation of U-Boot is complicated by the fact that U-Boot
5680 starts running out of ROM (flash memory), usually without access to
5681 system RAM (because the memory controller is not initialized yet).
5682 This means that we don't have writable Data or BSS segments, and BSS
5683 is not initialized as zero. To be able to get a C environment working
5684 at all, we have to allocate at least a minimal stack. Implementation
5685 options for this are defined and restricted by the CPU used: Some CPU
5686 models provide on-chip memory (like the IMMR area on MPC8xx and
5687 MPC826x processors), on others (parts of) the data cache can be
5688 locked as (mis-) used as memory, etc.
5690 Chris Hallinan posted a good summary of these issues to the
5691 U-Boot mailing list:
5693 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
5694 From: "Chris Hallinan" <clh@net1plus.com>
5695 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
5698 Correct me if I'm wrong, folks, but the way I understand it
5699 is this: Using DCACHE as initial RAM for Stack, etc, does not
5700 require any physical RAM backing up the cache. The cleverness
5701 is that the cache is being used as a temporary supply of
5702 necessary storage before the SDRAM controller is setup. It's
5703 beyond the scope of this list to explain the details, but you
5704 can see how this works by studying the cache architecture and
5705 operation in the architecture and processor-specific manuals.
5707 OCM is On Chip Memory, which I believe the 405GP has 4K. It
5708 is another option for the system designer to use as an
5709 initial stack/RAM area prior to SDRAM being available. Either
5710 option should work for you. Using CS 4 should be fine if your
5711 board designers haven't used it for something that would
5712 cause you grief during the initial boot! It is frequently not
5715 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
5716 with your processor/board/system design. The default value
5717 you will find in any recent u-boot distribution in
5718 walnut.h should work for you. I'd set it to a value larger
5719 than your SDRAM module. If you have a 64MB SDRAM module, set
5720 it above 400_0000. Just make sure your board has no resources
5721 that are supposed to respond to that address! That code in
5722 start.S has been around a while and should work as is when
5723 you get the config right.
5728 It is essential to remember this, since it has some impact on the C
5729 code for the initialization procedures:
5731 * Initialized global data (data segment) is read-only. Do not attempt
5734 * Do not use any uninitialized global data (or implicitly initialized
5735 as zero data - BSS segment) at all - this is undefined, initiali-
5736 zation is performed later (when relocating to RAM).
5738 * Stack space is very limited. Avoid big data buffers or things like
5741 Having only the stack as writable memory limits means we cannot use
5742 normal global data to share information between the code. But it
5743 turned out that the implementation of U-Boot can be greatly
5744 simplified by making a global data structure (gd_t) available to all
5745 functions. We could pass a pointer to this data as argument to _all_
5746 functions, but this would bloat the code. Instead we use a feature of
5747 the GCC compiler (Global Register Variables) to share the data: we
5748 place a pointer (gd) to the global data into a register which we
5749 reserve for this purpose.
5751 When choosing a register for such a purpose we are restricted by the
5752 relevant (E)ABI specifications for the current architecture, and by
5753 GCC's implementation.
5755 For PowerPC, the following registers have specific use:
5757 R2: reserved for system use
5758 R3-R4: parameter passing and return values
5759 R5-R10: parameter passing
5760 R13: small data area pointer
5764 (U-Boot also uses R12 as internal GOT pointer. r12
5765 is a volatile register so r12 needs to be reset when
5766 going back and forth between asm and C)
5768 ==> U-Boot will use R2 to hold a pointer to the global data
5770 Note: on PPC, we could use a static initializer (since the
5771 address of the global data structure is known at compile time),
5772 but it turned out that reserving a register results in somewhat
5773 smaller code - although the code savings are not that big (on
5774 average for all boards 752 bytes for the whole U-Boot image,
5775 624 text + 127 data).
5777 On ARM, the following registers are used:
5779 R0: function argument word/integer result
5780 R1-R3: function argument word
5781 R9: platform specific
5782 R10: stack limit (used only if stack checking is enabled)
5783 R11: argument (frame) pointer
5784 R12: temporary workspace
5787 R15: program counter
5789 ==> U-Boot will use R9 to hold a pointer to the global data
5791 Note: on ARM, only R_ARM_RELATIVE relocations are supported.
5793 On Nios II, the ABI is documented here:
5794 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
5796 ==> U-Boot will use gp to hold a pointer to the global data
5798 Note: on Nios II, we give "-G0" option to gcc and don't use gp
5799 to access small data sections, so gp is free.
5801 On NDS32, the following registers are used:
5803 R0-R1: argument/return
5805 R15: temporary register for assembler
5806 R16: trampoline register
5807 R28: frame pointer (FP)
5808 R29: global pointer (GP)
5809 R30: link register (LP)
5810 R31: stack pointer (SP)
5811 PC: program counter (PC)
5813 ==> U-Boot will use R10 to hold a pointer to the global data
5815 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
5816 or current versions of GCC may "optimize" the code too much.
5821 U-Boot runs in system state and uses physical addresses, i.e. the
5822 MMU is not used either for address mapping nor for memory protection.
5824 The available memory is mapped to fixed addresses using the memory
5825 controller. In this process, a contiguous block is formed for each
5826 memory type (Flash, SDRAM, SRAM), even when it consists of several
5827 physical memory banks.
5829 U-Boot is installed in the first 128 kB of the first Flash bank (on
5830 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
5831 booting and sizing and initializing DRAM, the code relocates itself
5832 to the upper end of DRAM. Immediately below the U-Boot code some
5833 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
5834 configuration setting]. Below that, a structure with global Board
5835 Info data is placed, followed by the stack (growing downward).
5837 Additionally, some exception handler code is copied to the low 8 kB
5838 of DRAM (0x00000000 ... 0x00001FFF).
5840 So a typical memory configuration with 16 MB of DRAM could look like
5843 0x0000 0000 Exception Vector code
5846 0x0000 2000 Free for Application Use
5852 0x00FB FF20 Monitor Stack (Growing downward)
5853 0x00FB FFAC Board Info Data and permanent copy of global data
5854 0x00FC 0000 Malloc Arena
5857 0x00FE 0000 RAM Copy of Monitor Code
5858 ... eventually: LCD or video framebuffer
5859 ... eventually: pRAM (Protected RAM - unchanged by reset)
5860 0x00FF FFFF [End of RAM]
5863 System Initialization:
5864 ----------------------
5866 In the reset configuration, U-Boot starts at the reset entry point
5867 (on most PowerPC systems at address 0x00000100). Because of the reset
5868 configuration for CS0# this is a mirror of the on board Flash memory.
5869 To be able to re-map memory U-Boot then jumps to its link address.
5870 To be able to implement the initialization code in C, a (small!)
5871 initial stack is set up in the internal Dual Ported RAM (in case CPUs
5872 which provide such a feature like MPC8xx or MPC8260), or in a locked
5873 part of the data cache. After that, U-Boot initializes the CPU core,
5874 the caches and the SIU.
5876 Next, all (potentially) available memory banks are mapped using a
5877 preliminary mapping. For example, we put them on 512 MB boundaries
5878 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
5879 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
5880 programmed for SDRAM access. Using the temporary configuration, a
5881 simple memory test is run that determines the size of the SDRAM
5884 When there is more than one SDRAM bank, and the banks are of
5885 different size, the largest is mapped first. For equal size, the first
5886 bank (CS2#) is mapped first. The first mapping is always for address
5887 0x00000000, with any additional banks following immediately to create
5888 contiguous memory starting from 0.
5890 Then, the monitor installs itself at the upper end of the SDRAM area
5891 and allocates memory for use by malloc() and for the global Board
5892 Info data; also, the exception vector code is copied to the low RAM
5893 pages, and the final stack is set up.
5895 Only after this relocation will you have a "normal" C environment;
5896 until that you are restricted in several ways, mostly because you are
5897 running from ROM, and because the code will have to be relocated to a
5901 U-Boot Porting Guide:
5902 ----------------------
5904 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
5908 int main(int argc, char *argv[])
5910 sighandler_t no_more_time;
5912 signal(SIGALRM, no_more_time);
5913 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
5915 if (available_money > available_manpower) {
5916 Pay consultant to port U-Boot;
5920 Download latest U-Boot source;
5922 Subscribe to u-boot mailing list;
5925 email("Hi, I am new to U-Boot, how do I get started?");
5928 Read the README file in the top level directory;
5929 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
5930 Read applicable doc/*.README;
5931 Read the source, Luke;
5932 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
5935 if (available_money > toLocalCurrency ($2500))
5938 Add a lot of aggravation and time;
5940 if (a similar board exists) { /* hopefully... */
5941 cp -a board/<similar> board/<myboard>
5942 cp include/configs/<similar>.h include/configs/<myboard>.h
5944 Create your own board support subdirectory;
5945 Create your own board include/configs/<myboard>.h file;
5947 Edit new board/<myboard> files
5948 Edit new include/configs/<myboard>.h
5953 Add / modify source code;
5957 email("Hi, I am having problems...");
5959 Send patch file to the U-Boot email list;
5960 if (reasonable critiques)
5961 Incorporate improvements from email list code review;
5963 Defend code as written;
5969 void no_more_time (int sig)
5978 All contributions to U-Boot should conform to the Linux kernel
5979 coding style; see the file "Documentation/CodingStyle" and the script
5980 "scripts/Lindent" in your Linux kernel source directory.
5982 Source files originating from a different project (for example the
5983 MTD subsystem) are generally exempt from these guidelines and are not
5984 reformatted to ease subsequent migration to newer versions of those
5987 Please note that U-Boot is implemented in C (and to some small parts in
5988 Assembler); no C++ is used, so please do not use C++ style comments (//)
5991 Please also stick to the following formatting rules:
5992 - remove any trailing white space
5993 - use TAB characters for indentation and vertical alignment, not spaces
5994 - make sure NOT to use DOS '\r\n' line feeds
5995 - do not add more than 2 consecutive empty lines to source files
5996 - do not add trailing empty lines to source files
5998 Submissions which do not conform to the standards may be returned
5999 with a request to reformat the changes.
6005 Since the number of patches for U-Boot is growing, we need to
6006 establish some rules. Submissions which do not conform to these rules
6007 may be rejected, even when they contain important and valuable stuff.
6009 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
6011 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
6012 see http://lists.denx.de/mailman/listinfo/u-boot
6014 When you send a patch, please include the following information with
6017 * For bug fixes: a description of the bug and how your patch fixes
6018 this bug. Please try to include a way of demonstrating that the
6019 patch actually fixes something.
6021 * For new features: a description of the feature and your
6024 * A CHANGELOG entry as plaintext (separate from the patch)
6026 * For major contributions, add a MAINTAINERS file with your
6027 information and associated file and directory references.
6029 * When you add support for a new board, don't forget to add a
6030 maintainer e-mail address to the boards.cfg file, too.
6032 * If your patch adds new configuration options, don't forget to
6033 document these in the README file.
6035 * The patch itself. If you are using git (which is *strongly*
6036 recommended) you can easily generate the patch using the
6037 "git format-patch". If you then use "git send-email" to send it to
6038 the U-Boot mailing list, you will avoid most of the common problems
6039 with some other mail clients.
6041 If you cannot use git, use "diff -purN OLD NEW". If your version of
6042 diff does not support these options, then get the latest version of
6045 The current directory when running this command shall be the parent
6046 directory of the U-Boot source tree (i. e. please make sure that
6047 your patch includes sufficient directory information for the
6050 We prefer patches as plain text. MIME attachments are discouraged,
6051 and compressed attachments must not be used.
6053 * If one logical set of modifications affects or creates several
6054 files, all these changes shall be submitted in a SINGLE patch file.
6056 * Changesets that contain different, unrelated modifications shall be
6057 submitted as SEPARATE patches, one patch per changeset.
6062 * Before sending the patch, run the buildman script on your patched
6063 source tree and make sure that no errors or warnings are reported
6064 for any of the boards.
6066 * Keep your modifications to the necessary minimum: A patch
6067 containing several unrelated changes or arbitrary reformats will be
6068 returned with a request to re-formatting / split it.
6070 * If you modify existing code, make sure that your new code does not
6071 add to the memory footprint of the code ;-) Small is beautiful!
6072 When adding new features, these should compile conditionally only
6073 (using #ifdef), and the resulting code with the new feature
6074 disabled must not need more memory than the old code without your
6077 * Remember that there is a size limit of 100 kB per message on the
6078 u-boot mailing list. Bigger patches will be moderated. If they are
6079 reasonable and not too big, they will be acknowledged. But patches
6080 bigger than the size limit should be avoided.