2 # (C) Copyright 2000 - 2013
3 # Wolfgang Denk, DENX Software Engineering, wd@denx.de.
5 # SPDX-License-Identifier: GPL-2.0+
11 This directory contains the source code for U-Boot, a boot loader for
12 Embedded boards based on PowerPC, ARM, MIPS and several other
13 processors, which can be installed in a boot ROM and used to
14 initialize and test the hardware or to download and run application
17 The development of U-Boot is closely related to Linux: some parts of
18 the source code originate in the Linux source tree, we have some
19 header files in common, and special provision has been made to
20 support booting of Linux images.
22 Some attention has been paid to make this software easily
23 configurable and extendable. For instance, all monitor commands are
24 implemented with the same call interface, so that it's very easy to
25 add new commands. Also, instead of permanently adding rarely used
26 code (for instance hardware test utilities) to the monitor, you can
27 load and run it dynamically.
33 In general, all boards for which a configuration option exists in the
34 Makefile have been tested to some extent and can be considered
35 "working". In fact, many of them are used in production systems.
37 In case of problems see the CHANGELOG file to find out who contributed
38 the specific port. In addition, there are various MAINTAINERS files
39 scattered throughout the U-Boot source identifying the people or
40 companies responsible for various boards and subsystems.
42 Note: As of August, 2010, there is no longer a CHANGELOG file in the
43 actual U-Boot source tree; however, it can be created dynamically
44 from the Git log using:
52 In case you have questions about, problems with or contributions for
53 U-Boot, you should send a message to the U-Boot mailing list at
54 <u-boot@lists.denx.de>. There is also an archive of previous traffic
55 on the mailing list - please search the archive before asking FAQ's.
56 Please see http://lists.denx.de/pipermail/u-boot and
57 http://dir.gmane.org/gmane.comp.boot-loaders.u-boot
60 Where to get source code:
61 =========================
63 The U-Boot source code is maintained in the Git repository at
64 git://www.denx.de/git/u-boot.git ; you can browse it online at
65 http://www.denx.de/cgi-bin/gitweb.cgi?p=u-boot.git;a=summary
67 The "snapshot" links on this page allow you to download tarballs of
68 any version you might be interested in. Official releases are also
69 available for FTP download from the ftp://ftp.denx.de/pub/u-boot/
72 Pre-built (and tested) images are available from
73 ftp://ftp.denx.de/pub/u-boot/images/
79 - start from 8xxrom sources
80 - create PPCBoot project (http://sourceforge.net/projects/ppcboot)
82 - make it easier to add custom boards
83 - make it possible to add other [PowerPC] CPUs
84 - extend functions, especially:
85 * Provide extended interface to Linux boot loader
88 * PCMCIA / CompactFlash / ATA disk / SCSI ... boot
89 - create ARMBoot project (http://sourceforge.net/projects/armboot)
90 - add other CPU families (starting with ARM)
91 - create U-Boot project (http://sourceforge.net/projects/u-boot)
92 - current project page: see http://www.denx.de/wiki/U-Boot
98 The "official" name of this project is "Das U-Boot". The spelling
99 "U-Boot" shall be used in all written text (documentation, comments
100 in source files etc.). Example:
102 This is the README file for the U-Boot project.
104 File names etc. shall be based on the string "u-boot". Examples:
106 include/asm-ppc/u-boot.h
108 #include <asm/u-boot.h>
110 Variable names, preprocessor constants etc. shall be either based on
111 the string "u_boot" or on "U_BOOT". Example:
113 U_BOOT_VERSION u_boot_logo
114 IH_OS_U_BOOT u_boot_hush_start
120 Starting with the release in October 2008, the names of the releases
121 were changed from numerical release numbers without deeper meaning
122 into a time stamp based numbering. Regular releases are identified by
123 names consisting of the calendar year and month of the release date.
124 Additional fields (if present) indicate release candidates or bug fix
125 releases in "stable" maintenance trees.
128 U-Boot v2009.11 - Release November 2009
129 U-Boot v2009.11.1 - Release 1 in version November 2009 stable tree
130 U-Boot v2010.09-rc1 - Release candidate 1 for September 2010 release
136 /arch Architecture specific files
137 /arc Files generic to ARC architecture
138 /arm Files generic to ARM architecture
139 /avr32 Files generic to AVR32 architecture
140 /m68k Files generic to m68k architecture
141 /microblaze Files generic to microblaze architecture
142 /mips Files generic to MIPS architecture
143 /nds32 Files generic to NDS32 architecture
144 /nios2 Files generic to Altera NIOS2 architecture
145 /openrisc Files generic to OpenRISC architecture
146 /powerpc Files generic to PowerPC architecture
147 /sandbox Files generic to HW-independent "sandbox"
148 /sh Files generic to SH architecture
149 /x86 Files generic to x86 architecture
150 /api Machine/arch independent API for external apps
151 /board Board dependent files
152 /cmd U-Boot commands functions
153 /common Misc architecture independent functions
154 /configs Board default configuration files
155 /disk Code for disk drive partition handling
156 /doc Documentation (don't expect too much)
157 /drivers Commonly used device drivers
158 /dts Contains Makefile for building internal U-Boot fdt.
159 /examples Example code for standalone applications, etc.
160 /fs Filesystem code (cramfs, ext2, jffs2, etc.)
161 /include Header Files
162 /lib Library routines generic to all architectures
163 /Licenses Various license files
165 /post Power On Self Test
166 /scripts Various build scripts and Makefiles
167 /test Various unit test files
168 /tools Tools to build S-Record or U-Boot images, etc.
170 Software Configuration:
171 =======================
173 Configuration is usually done using C preprocessor defines; the
174 rationale behind that is to avoid dead code whenever possible.
176 There are two classes of configuration variables:
178 * Configuration _OPTIONS_:
179 These are selectable by the user and have names beginning with
182 * Configuration _SETTINGS_:
183 These depend on the hardware etc. and should not be meddled with if
184 you don't know what you're doing; they have names beginning with
187 Previously, all configuration was done by hand, which involved creating
188 symbolic links and editing configuration files manually. More recently,
189 U-Boot has added the Kbuild infrastructure used by the Linux kernel,
190 allowing you to use the "make menuconfig" command to configure your
194 Selection of Processor Architecture and Board Type:
195 ---------------------------------------------------
197 For all supported boards there are ready-to-use default
198 configurations available; just type "make <board_name>_defconfig".
200 Example: For a TQM823L module type:
203 make TQM823L_defconfig
205 Note: If you're looking for the default configuration file for a board
206 you're sure used to be there but is now missing, check the file
207 doc/README.scrapyard for a list of no longer supported boards.
212 U-Boot can be built natively to run on a Linux host using the 'sandbox'
213 board. This allows feature development which is not board- or architecture-
214 specific to be undertaken on a native platform. The sandbox is also used to
215 run some of U-Boot's tests.
217 See board/sandbox/README.sandbox for more details.
220 Board Initialisation Flow:
221 --------------------------
223 This is the intended start-up flow for boards. This should apply for both
224 SPL and U-Boot proper (i.e. they both follow the same rules).
226 Note: "SPL" stands for "Secondary Program Loader," which is explained in
227 more detail later in this file.
229 At present, SPL mostly uses a separate code path, but the function names
230 and roles of each function are the same. Some boards or architectures
231 may not conform to this. At least most ARM boards which use
232 CONFIG_SPL_FRAMEWORK conform to this.
234 Execution typically starts with an architecture-specific (and possibly
235 CPU-specific) start.S file, such as:
237 - arch/arm/cpu/armv7/start.S
238 - arch/powerpc/cpu/mpc83xx/start.S
239 - arch/mips/cpu/start.S
241 and so on. From there, three functions are called; the purpose and
242 limitations of each of these functions are described below.
245 - purpose: essential init to permit execution to reach board_init_f()
246 - no global_data or BSS
247 - there is no stack (ARMv7 may have one but it will soon be removed)
248 - must not set up SDRAM or use console
249 - must only do the bare minimum to allow execution to continue to
251 - this is almost never needed
252 - return normally from this function
255 - purpose: set up the machine ready for running board_init_r():
256 i.e. SDRAM and serial UART
257 - global_data is available
259 - BSS is not available, so you cannot use global/static variables,
260 only stack variables and global_data
262 Non-SPL-specific notes:
263 - dram_init() is called to set up DRAM. If already done in SPL this
267 - you can override the entire board_init_f() function with your own
269 - preloader_console_init() can be called here in extremis
270 - should set up SDRAM, and anything needed to make the UART work
271 - these is no need to clear BSS, it will be done by crt0.S
272 - must return normally from this function (don't call board_init_r()
275 Here the BSS is cleared. For SPL, if CONFIG_SPL_STACK_R is defined, then at
276 this point the stack and global_data are relocated to below
277 CONFIG_SPL_STACK_R_ADDR. For non-SPL, U-Boot is relocated to run at the top of
281 - purpose: main execution, common code
282 - global_data is available
284 - BSS is available, all static/global variables can be used
285 - execution eventually continues to main_loop()
287 Non-SPL-specific notes:
288 - U-Boot is relocated to the top of memory and is now running from
292 - stack is optionally in SDRAM, if CONFIG_SPL_STACK_R is defined and
293 CONFIG_SPL_STACK_R_ADDR points into SDRAM
294 - preloader_console_init() can be called here - typically this is
295 done by selecting CONFIG_SPL_BOARD_INIT and then supplying a
296 spl_board_init() function containing this call
297 - loads U-Boot or (in falcon mode) Linux
301 Configuration Options:
302 ----------------------
304 Configuration depends on the combination of board and CPU type; all
305 such information is kept in a configuration file
306 "include/configs/<board_name>.h".
308 Example: For a TQM823L module, all configuration settings are in
309 "include/configs/TQM823L.h".
312 Many of the options are named exactly as the corresponding Linux
313 kernel configuration options. The intention is to make it easier to
314 build a config tool - later.
317 The following options need to be configured:
319 - CPU Type: Define exactly one, e.g. CONFIG_MPC85XX.
321 - Board Type: Define exactly one, e.g. CONFIG_MPC8540ADS.
323 - CPU Daughterboard Type: (if CONFIG_ATSTK1000 is defined)
324 Define exactly one, e.g. CONFIG_ATSTK1002
326 - Marvell Family Member
327 CONFIG_SYS_MVFS - define it if you want to enable
328 multiple fs option at one time
329 for marvell soc family
331 - 8xx CPU Options: (if using an MPC8xx CPU)
332 CONFIG_8xx_GCLK_FREQ - deprecated: CPU clock if
333 get_gclk_freq() cannot work
334 e.g. if there is no 32KHz
335 reference PIT/RTC clock
336 CONFIG_8xx_OSCLK - PLL input clock (either EXTCLK
339 - 859/866/885 CPU options: (if using a MPC859 or MPC866 or MPC885 CPU):
340 CONFIG_SYS_8xx_CPUCLK_MIN
341 CONFIG_SYS_8xx_CPUCLK_MAX
342 CONFIG_8xx_CPUCLK_DEFAULT
343 See doc/README.MPC866
345 CONFIG_SYS_MEASURE_CPUCLK
347 Define this to measure the actual CPU clock instead
348 of relying on the correctness of the configured
349 values. Mostly useful for board bringup to make sure
350 the PLL is locked at the intended frequency. Note
351 that this requires a (stable) reference clock (32 kHz
352 RTC clock or CONFIG_SYS_8XX_XIN)
354 CONFIG_SYS_DELAYED_ICACHE
356 Define this option if you want to enable the
357 ICache only when Code runs from RAM.
362 Specifies that the core is a 64-bit PowerPC implementation (implements
363 the "64" category of the Power ISA). This is necessary for ePAPR
364 compliance, among other possible reasons.
366 CONFIG_SYS_FSL_TBCLK_DIV
368 Defines the core time base clock divider ratio compared to the
369 system clock. On most PQ3 devices this is 8, on newer QorIQ
370 devices it can be 16 or 32. The ratio varies from SoC to Soc.
372 CONFIG_SYS_FSL_PCIE_COMPAT
374 Defines the string to utilize when trying to match PCIe device
375 tree nodes for the given platform.
377 CONFIG_SYS_FSL_ERRATUM_A004510
379 Enables a workaround for erratum A004510. If set,
380 then CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV and
381 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY must be set.
383 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV
384 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV2 (optional)
386 Defines one or two SoC revisions (low 8 bits of SVR)
387 for which the A004510 workaround should be applied.
389 The rest of SVR is either not relevant to the decision
390 of whether the erratum is present (e.g. p2040 versus
391 p2041) or is implied by the build target, which controls
392 whether CONFIG_SYS_FSL_ERRATUM_A004510 is set.
394 See Freescale App Note 4493 for more information about
397 CONFIG_A003399_NOR_WORKAROUND
398 Enables a workaround for IFC erratum A003399. It is only
399 required during NOR boot.
401 CONFIG_A008044_WORKAROUND
402 Enables a workaround for T1040/T1042 erratum A008044. It is only
403 required during NAND boot and valid for Rev 1.0 SoC revision
405 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY
407 This is the value to write into CCSR offset 0x18600
408 according to the A004510 workaround.
410 CONFIG_SYS_FSL_DSP_DDR_ADDR
411 This value denotes start offset of DDR memory which is
412 connected exclusively to the DSP cores.
414 CONFIG_SYS_FSL_DSP_M2_RAM_ADDR
415 This value denotes start offset of M2 memory
416 which is directly connected to the DSP core.
418 CONFIG_SYS_FSL_DSP_M3_RAM_ADDR
419 This value denotes start offset of M3 memory which is directly
420 connected to the DSP core.
422 CONFIG_SYS_FSL_DSP_CCSRBAR_DEFAULT
423 This value denotes start offset of DSP CCSR space.
425 CONFIG_SYS_FSL_SINGLE_SOURCE_CLK
426 Single Source Clock is clocking mode present in some of FSL SoC's.
427 In this mode, a single differential clock is used to supply
428 clocks to the sysclock, ddrclock and usbclock.
430 CONFIG_SYS_CPC_REINIT_F
431 This CONFIG is defined when the CPC is configured as SRAM at the
432 time of U-Boot entry and is required to be re-initialized.
435 Indicates this SoC supports deep sleep feature. If deep sleep is
436 supported, core will start to execute uboot when wakes up.
438 - Generic CPU options:
439 CONFIG_SYS_GENERIC_GLOBAL_DATA
440 Defines global data is initialized in generic board board_init_f().
441 If this macro is defined, global data is created and cleared in
442 generic board board_init_f(). Without this macro, architecture/board
443 should initialize global data before calling board_init_f().
445 CONFIG_SYS_BIG_ENDIAN, CONFIG_SYS_LITTLE_ENDIAN
447 Defines the endianess of the CPU. Implementation of those
448 values is arch specific.
451 Freescale DDR driver in use. This type of DDR controller is
452 found in mpc83xx, mpc85xx, mpc86xx as well as some ARM core
455 CONFIG_SYS_FSL_DDR_ADDR
456 Freescale DDR memory-mapped register base.
458 CONFIG_SYS_FSL_DDR_EMU
459 Specify emulator support for DDR. Some DDR features such as
460 deskew training are not available.
462 CONFIG_SYS_FSL_DDRC_GEN1
463 Freescale DDR1 controller.
465 CONFIG_SYS_FSL_DDRC_GEN2
466 Freescale DDR2 controller.
468 CONFIG_SYS_FSL_DDRC_GEN3
469 Freescale DDR3 controller.
471 CONFIG_SYS_FSL_DDRC_GEN4
472 Freescale DDR4 controller.
474 CONFIG_SYS_FSL_DDRC_ARM_GEN3
475 Freescale DDR3 controller for ARM-based SoCs.
478 Board config to use DDR1. It can be enabled for SoCs with
479 Freescale DDR1 or DDR2 controllers, depending on the board
483 Board config to use DDR2. It can be enabled for SoCs with
484 Freescale DDR2 or DDR3 controllers, depending on the board
488 Board config to use DDR3. It can be enabled for SoCs with
489 Freescale DDR3 or DDR3L controllers.
492 Board config to use DDR3L. It can be enabled for SoCs with
496 Board config to use DDR4. It can be enabled for SoCs with
499 CONFIG_SYS_FSL_IFC_BE
500 Defines the IFC controller register space as Big Endian
502 CONFIG_SYS_FSL_IFC_LE
503 Defines the IFC controller register space as Little Endian
505 CONFIG_SYS_FSL_IFC_CLK_DIV
506 Defines divider of platform clock(clock input to IFC controller).
508 CONFIG_SYS_FSL_LBC_CLK_DIV
509 Defines divider of platform clock(clock input to eLBC controller).
511 CONFIG_SYS_FSL_PBL_PBI
512 It enables addition of RCW (Power on reset configuration) in built image.
513 Please refer doc/README.pblimage for more details
515 CONFIG_SYS_FSL_PBL_RCW
516 It adds PBI(pre-boot instructions) commands in u-boot build image.
517 PBI commands can be used to configure SoC before it starts the execution.
518 Please refer doc/README.pblimage for more details
521 It adds a target to create boot binary having SPL binary in PBI format
522 concatenated with u-boot binary.
524 CONFIG_SYS_FSL_DDR_BE
525 Defines the DDR controller register space as Big Endian
527 CONFIG_SYS_FSL_DDR_LE
528 Defines the DDR controller register space as Little Endian
530 CONFIG_SYS_FSL_DDR_SDRAM_BASE_PHY
531 Physical address from the view of DDR controllers. It is the
532 same as CONFIG_SYS_DDR_SDRAM_BASE for all Power SoCs. But
533 it could be different for ARM SoCs.
535 CONFIG_SYS_FSL_DDR_INTLV_256B
536 DDR controller interleaving on 256-byte. This is a special
537 interleaving mode, handled by Dickens for Freescale layerscape
540 CONFIG_SYS_FSL_DDR_MAIN_NUM_CTRLS
541 Number of controllers used as main memory.
543 CONFIG_SYS_FSL_OTHER_DDR_NUM_CTRLS
544 Number of controllers used for other than main memory.
546 CONFIG_SYS_FSL_HAS_DP_DDR
547 Defines the SoC has DP-DDR used for DPAA.
549 CONFIG_SYS_FSL_SEC_BE
550 Defines the SEC controller register space as Big Endian
552 CONFIG_SYS_FSL_SEC_LE
553 Defines the SEC controller register space as Little Endian
556 CONFIG_SYS_INIT_SP_OFFSET
558 Offset relative to CONFIG_SYS_SDRAM_BASE for initial stack
559 pointer. This is needed for the temporary stack before
562 CONFIG_SYS_MIPS_CACHE_MODE
564 Cache operation mode for the MIPS CPU.
565 See also arch/mips/include/asm/mipsregs.h.
567 CONF_CM_CACHABLE_NO_WA
570 CONF_CM_CACHABLE_NONCOHERENT
574 CONF_CM_CACHABLE_ACCELERATED
576 CONFIG_SYS_XWAY_EBU_BOOTCFG
578 Special option for Lantiq XWAY SoCs for booting from NOR flash.
579 See also arch/mips/cpu/mips32/start.S.
581 CONFIG_XWAY_SWAP_BYTES
583 Enable compilation of tools/xway-swap-bytes needed for Lantiq
584 XWAY SoCs for booting from NOR flash. The U-Boot image needs to
585 be swapped if a flash programmer is used.
588 CONFIG_SYS_EXCEPTION_VECTORS_HIGH
590 Select high exception vectors of the ARM core, e.g., do not
591 clear the V bit of the c1 register of CP15.
594 Generic timer clock source frequency.
596 COUNTER_FREQUENCY_REAL
597 Generic timer clock source frequency if the real clock is
598 different from COUNTER_FREQUENCY, and can only be determined
602 CONFIG_TEGRA_SUPPORT_NON_SECURE
604 Support executing U-Boot in non-secure (NS) mode. Certain
605 impossible actions will be skipped if the CPU is in NS mode,
606 such as ARM architectural timer initialization.
608 - Linux Kernel Interface:
611 U-Boot stores all clock information in Hz
612 internally. For binary compatibility with older Linux
613 kernels (which expect the clocks passed in the
614 bd_info data to be in MHz) the environment variable
615 "clocks_in_mhz" can be defined so that U-Boot
616 converts clock data to MHZ before passing it to the
618 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
619 "clocks_in_mhz=1" is automatically included in the
622 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
624 When transferring memsize parameter to Linux, some versions
625 expect it to be in bytes, others in MB.
626 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
630 New kernel versions are expecting firmware settings to be
631 passed using flattened device trees (based on open firmware
635 * New libfdt-based support
636 * Adds the "fdt" command
637 * The bootm command automatically updates the fdt
639 OF_CPU - The proper name of the cpus node (only required for
640 MPC512X and MPC5xxx based boards).
641 OF_SOC - The proper name of the soc node (only required for
642 MPC512X and MPC5xxx based boards).
643 OF_TBCLK - The timebase frequency.
644 OF_STDOUT_PATH - The path to the console device
646 boards with QUICC Engines require OF_QE to set UCC MAC
649 CONFIG_OF_BOARD_SETUP
651 Board code has addition modification that it wants to make
652 to the flat device tree before handing it off to the kernel
654 CONFIG_OF_SYSTEM_SETUP
656 Other code has addition modification that it wants to make
657 to the flat device tree before handing it off to the kernel.
658 This causes ft_system_setup() to be called before booting
663 U-Boot can detect if an IDE device is present or not.
664 If not, and this new config option is activated, U-Boot
665 removes the ATA node from the DTS before booting Linux,
666 so the Linux IDE driver does not probe the device and
667 crash. This is needed for buggy hardware (uc101) where
668 no pull down resistor is connected to the signal IDE5V_DD7.
670 CONFIG_MACH_TYPE [relevant for ARM only][mandatory]
672 This setting is mandatory for all boards that have only one
673 machine type and must be used to specify the machine type
674 number as it appears in the ARM machine registry
675 (see http://www.arm.linux.org.uk/developer/machines/).
676 Only boards that have multiple machine types supported
677 in a single configuration file and the machine type is
678 runtime discoverable, do not have to use this setting.
680 - vxWorks boot parameters:
682 bootvx constructs a valid bootline using the following
683 environments variables: bootdev, bootfile, ipaddr, netmask,
684 serverip, gatewayip, hostname, othbootargs.
685 It loads the vxWorks image pointed bootfile.
687 Note: If a "bootargs" environment is defined, it will overwride
688 the defaults discussed just above.
690 - Cache Configuration:
691 CONFIG_SYS_ICACHE_OFF - Do not enable instruction cache in U-Boot
692 CONFIG_SYS_DCACHE_OFF - Do not enable data cache in U-Boot
693 CONFIG_SYS_L2CACHE_OFF- Do not enable L2 cache in U-Boot
695 - Cache Configuration for ARM:
696 CONFIG_SYS_L2_PL310 - Enable support for ARM PL310 L2 cache
698 CONFIG_SYS_PL310_BASE - Physical base address of PL310
699 controller register space
704 Define this if you want support for Amba PrimeCell PL010 UARTs.
708 Define this if you want support for Amba PrimeCell PL011 UARTs.
712 If you have Amba PrimeCell PL011 UARTs, set this variable to
713 the clock speed of the UARTs.
717 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
718 define this to a list of base addresses for each (supported)
719 port. See e.g. include/configs/versatile.h
721 CONFIG_SERIAL_HW_FLOW_CONTROL
723 Define this variable to enable hw flow control in serial driver.
724 Current user of this option is drivers/serial/nsl16550.c driver
727 Depending on board, define exactly one serial port
728 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
729 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
730 console by defining CONFIG_8xx_CONS_NONE
732 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
733 port routines must be defined elsewhere
734 (i.e. serial_init(), serial_getc(), ...)
737 CONFIG_BAUDRATE - in bps
738 Select one of the baudrates listed in
739 CONFIG_SYS_BAUDRATE_TABLE, see below.
740 CONFIG_SYS_BRGCLK_PRESCALE, baudrate prescale
742 - Console Rx buffer length
743 With CONFIG_SYS_SMC_RXBUFLEN it is possible to define
744 the maximum receive buffer length for the SMC.
745 This option is actual only for 82xx and 8xx possible.
746 If using CONFIG_SYS_SMC_RXBUFLEN also CONFIG_SYS_MAXIDLE
747 must be defined, to setup the maximum idle timeout for
752 Only needed when CONFIG_BOOTDELAY is enabled;
753 define a command string that is automatically executed
754 when no character is read on the console interface
755 within "Boot Delay" after reset.
758 This can be used to pass arguments to the bootm
759 command. The value of CONFIG_BOOTARGS goes into the
760 environment value "bootargs".
762 CONFIG_RAMBOOT and CONFIG_NFSBOOT
763 The value of these goes into the environment as
764 "ramboot" and "nfsboot" respectively, and can be used
765 as a convenience, when switching between booting from
769 CONFIG_BOOTCOUNT_LIMIT
770 Implements a mechanism for detecting a repeating reboot
772 http://www.denx.de/wiki/view/DULG/UBootBootCountLimit
775 If no softreset save registers are found on the hardware
776 "bootcount" is stored in the environment. To prevent a
777 saveenv on all reboots, the environment variable
778 "upgrade_available" is used. If "upgrade_available" is
779 0, "bootcount" is always 0, if "upgrade_available" is
780 1 "bootcount" is incremented in the environment.
781 So the Userspace Applikation must set the "upgrade_available"
782 and "bootcount" variable to 0, if a boot was successfully.
787 When this option is #defined, the existence of the
788 environment variable "preboot" will be checked
789 immediately before starting the CONFIG_BOOTDELAY
790 countdown and/or running the auto-boot command resp.
791 entering interactive mode.
793 This feature is especially useful when "preboot" is
794 automatically generated or modified. For an example
795 see the LWMON board specific code: here "preboot" is
796 modified when the user holds down a certain
797 combination of keys on the (special) keyboard when
800 - Serial Download Echo Mode:
802 If defined to 1, all characters received during a
803 serial download (using the "loads" command) are
804 echoed back. This might be needed by some terminal
805 emulations (like "cu"), but may as well just take
806 time on others. This setting #define's the initial
807 value of the "loads_echo" environment variable.
809 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
811 Select one of the baudrates listed in
812 CONFIG_SYS_BAUDRATE_TABLE, see below.
815 Monitor commands can be included or excluded
816 from the build by using the #include files
817 <config_cmd_all.h> and #undef'ing unwanted
818 commands, or adding #define's for wanted commands.
820 The default command configuration includes all commands
821 except those marked below with a "*".
823 CONFIG_CMD_AES AES 128 CBC encrypt/decrypt
824 CONFIG_CMD_ASKENV * ask for env variable
825 CONFIG_CMD_BDI bdinfo
826 CONFIG_CMD_BOOTD bootd
827 CONFIG_CMD_BOOTI * ARM64 Linux kernel Image support
828 CONFIG_CMD_CACHE * icache, dcache
829 CONFIG_CMD_CONSOLE coninfo
830 CONFIG_CMD_CRC32 * crc32
831 CONFIG_CMD_DHCP * DHCP support
832 CONFIG_CMD_DIAG * Diagnostics
833 CONFIG_CMD_ECHO echo arguments
834 CONFIG_CMD_EDITENV edit env variable
835 CONFIG_CMD_ELF * bootelf, bootvx
836 CONFIG_CMD_ENV_EXISTS * check existence of env variable
837 CONFIG_CMD_EXPORTENV * export the environment
838 CONFIG_CMD_EXT2 * ext2 command support
839 CONFIG_CMD_EXT4 * ext4 command support
840 CONFIG_CMD_FS_GENERIC * filesystem commands (e.g. load, ls)
841 that work for multiple fs types
842 CONFIG_CMD_FS_UUID * Look up a filesystem UUID
843 CONFIG_CMD_SAVEENV saveenv
844 CONFIG_CMD_FAT * FAT command support
845 CONFIG_CMD_FLASH flinfo, erase, protect
846 CONFIG_CMD_FPGA FPGA device initialization support
847 CONFIG_CMD_GO * the 'go' command (exec code)
848 CONFIG_CMD_GREPENV * search environment
849 CONFIG_CMD_I2C * I2C serial bus support
850 CONFIG_CMD_IMI iminfo
851 CONFIG_CMD_IMLS List all images found in NOR flash
852 CONFIG_CMD_IMLS_NAND * List all images found in NAND flash
853 CONFIG_CMD_IMPORTENV * import an environment
854 CONFIG_CMD_INI * import data from an ini file into the env
855 CONFIG_CMD_ITEST Integer/string test of 2 values
856 CONFIG_CMD_KGDB * kgdb
857 CONFIG_CMD_LDRINFO * ldrinfo (display Blackfin loader)
858 CONFIG_CMD_LINK_LOCAL * link-local IP address auto-configuration
860 CONFIG_CMD_LOADB loadb
861 CONFIG_CMD_LOADS loads
862 CONFIG_CMD_MD5SUM * print md5 message digest
863 (requires CONFIG_CMD_MEMORY and CONFIG_MD5)
864 CONFIG_CMD_MEMINFO * Display detailed memory information
865 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
867 CONFIG_CMD_MEMTEST * mtest
868 CONFIG_CMD_MISC Misc functions like sleep etc
869 CONFIG_CMD_MMC * MMC memory mapped support
870 CONFIG_CMD_MII * MII utility commands
871 CONFIG_CMD_MTDPARTS * MTD partition support
872 CONFIG_CMD_NAND * NAND support
873 CONFIG_CMD_NET bootp, tftpboot, rarpboot
874 CONFIG_CMD_NFS NFS support
875 CONFIG_CMD_PCA953X * PCA953x I2C gpio commands
876 CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command
877 CONFIG_CMD_PCI * pciinfo
878 CONFIG_CMD_PCMCIA * PCMCIA support
879 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
881 CONFIG_CMD_PORTIO * Port I/O
882 CONFIG_CMD_READ * Read raw data from partition
883 CONFIG_CMD_REGINFO * Register dump
884 CONFIG_CMD_RUN run command in env variable
885 CONFIG_CMD_SANDBOX * sb command to access sandbox features
886 CONFIG_CMD_SAVES * save S record dump
887 CONFIG_SCSI * SCSI Support
888 CONFIG_CMD_SDRAM * print SDRAM configuration information
889 (requires CONFIG_CMD_I2C)
890 CONFIG_CMD_SETGETDCR Support for DCR Register access
892 CONFIG_CMD_SF * Read/write/erase SPI NOR flash
893 CONFIG_CMD_SHA1SUM * print sha1 memory digest
894 (requires CONFIG_CMD_MEMORY)
895 CONFIG_CMD_SOFTSWITCH * Soft switch setting command for BF60x
896 CONFIG_CMD_SOURCE "source" command Support
897 CONFIG_CMD_SPI * SPI serial bus support
898 CONFIG_CMD_TFTPSRV * TFTP transfer in server mode
899 CONFIG_CMD_TFTPPUT * TFTP put command (upload)
900 CONFIG_CMD_TIME * run command and report execution time (ARM specific)
901 CONFIG_CMD_TIMER * access to the system tick timer
902 CONFIG_CMD_USB * USB support
903 CONFIG_CMD_CDP * Cisco Discover Protocol support
904 CONFIG_CMD_MFSL * Microblaze FSL support
905 CONFIG_CMD_XIMG Load part of Multi Image
906 CONFIG_CMD_UUID * Generate random UUID or GUID string
908 EXAMPLE: If you want all functions except of network
909 support you can write:
911 #include "config_cmd_all.h"
912 #undef CONFIG_CMD_NET
915 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
917 Note: Don't enable the "icache" and "dcache" commands
918 (configuration option CONFIG_CMD_CACHE) unless you know
919 what you (and your U-Boot users) are doing. Data
920 cache cannot be enabled on systems like the 8xx or
921 8260 (where accesses to the IMMR region must be
922 uncached), and it cannot be disabled on all other
923 systems where we (mis-) use the data cache to hold an
924 initial stack and some data.
927 XXX - this list needs to get updated!
929 - Removal of commands
930 If no commands are needed to boot, you can disable
931 CONFIG_CMDLINE to remove them. In this case, the command line
932 will not be available, and when U-Boot wants to execute the
933 boot command (on start-up) it will call board_run_command()
934 instead. This can reduce image size significantly for very
935 simple boot procedures.
937 - Regular expression support:
939 If this variable is defined, U-Boot is linked against
940 the SLRE (Super Light Regular Expression) library,
941 which adds regex support to some commands, as for
942 example "env grep" and "setexpr".
946 If this variable is defined, U-Boot will use a device tree
947 to configure its devices, instead of relying on statically
948 compiled #defines in the board file. This option is
949 experimental and only available on a few boards. The device
950 tree is available in the global data as gd->fdt_blob.
952 U-Boot needs to get its device tree from somewhere. This can
953 be done using one of the three options below:
956 If this variable is defined, U-Boot will embed a device tree
957 binary in its image. This device tree file should be in the
958 board directory and called <soc>-<board>.dts. The binary file
959 is then picked up in board_init_f() and made available through
960 the global data structure as gd->blob.
963 If this variable is defined, U-Boot will build a device tree
964 binary. It will be called u-boot.dtb. Architecture-specific
965 code will locate it at run-time. Generally this works by:
967 cat u-boot.bin u-boot.dtb >image.bin
969 and in fact, U-Boot does this for you, creating a file called
970 u-boot-dtb.bin which is useful in the common case. You can
971 still use the individual files if you need something more
975 If this variable is defined, U-Boot will use the device tree
976 provided by the board at runtime instead of embedding one with
977 the image. Only boards defining board_fdt_blob_setup() support
978 this option (see include/fdtdec.h file).
982 If this variable is defined, it enables watchdog
983 support for the SoC. There must be support in the SoC
984 specific code for a watchdog. For the 8xx and 8260
985 CPUs, the SIU Watchdog feature is enabled in the SYPCR
986 register. When supported for a specific SoC is
987 available, then no further board specific code should
991 When using a watchdog circuitry external to the used
992 SoC, then define this variable and provide board
993 specific code for the "hw_watchdog_reset" function.
995 CONFIG_AT91_HW_WDT_TIMEOUT
996 specify the timeout in seconds. default 2 seconds.
999 CONFIG_VERSION_VARIABLE
1000 If this variable is defined, an environment variable
1001 named "ver" is created by U-Boot showing the U-Boot
1002 version as printed by the "version" command.
1003 Any change to this variable will be reverted at the
1008 When CONFIG_CMD_DATE is selected, the type of the RTC
1009 has to be selected, too. Define exactly one of the
1012 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
1013 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
1014 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC
1015 CONFIG_RTC_MC146818 - use MC146818 RTC
1016 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
1017 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
1018 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
1019 CONFIG_RTC_DS1339 - use Maxim, Inc. DS1339 RTC
1020 CONFIG_RTC_DS164x - use Dallas DS164x RTC
1021 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
1022 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
1023 CONFIG_SYS_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
1024 CONFIG_SYS_RV3029_TCR - enable trickle charger on
1027 Note that if the RTC uses I2C, then the I2C interface
1028 must also be configured. See I2C Support, below.
1031 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
1033 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
1034 chip-ngpio pairs that tell the PCA953X driver the number of
1035 pins supported by a particular chip.
1037 Note that if the GPIO device uses I2C, then the I2C interface
1038 must also be configured. See I2C Support, below.
1041 When CONFIG_IO_TRACE is selected, U-Boot intercepts all I/O
1042 accesses and can checksum them or write a list of them out
1043 to memory. See the 'iotrace' command for details. This is
1044 useful for testing device drivers since it can confirm that
1045 the driver behaves the same way before and after a code
1046 change. Currently this is supported on sandbox and arm. To
1047 add support for your architecture, add '#include <iotrace.h>'
1048 to the bottom of arch/<arch>/include/asm/io.h and test.
1050 Example output from the 'iotrace stats' command is below.
1051 Note that if the trace buffer is exhausted, the checksum will
1052 still continue to operate.
1055 Start: 10000000 (buffer start address)
1056 Size: 00010000 (buffer size)
1057 Offset: 00000120 (current buffer offset)
1058 Output: 10000120 (start + offset)
1059 Count: 00000018 (number of trace records)
1060 CRC32: 9526fb66 (CRC32 of all trace records)
1062 - Timestamp Support:
1064 When CONFIG_TIMESTAMP is selected, the timestamp
1065 (date and time) of an image is printed by image
1066 commands like bootm or iminfo. This option is
1067 automatically enabled when you select CONFIG_CMD_DATE .
1069 - Partition Labels (disklabels) Supported:
1070 Zero or more of the following:
1071 CONFIG_MAC_PARTITION Apple's MacOS partition table.
1072 CONFIG_DOS_PARTITION MS Dos partition table, traditional on the
1073 Intel architecture, USB sticks, etc.
1074 CONFIG_ISO_PARTITION ISO partition table, used on CDROM etc.
1075 CONFIG_EFI_PARTITION GPT partition table, common when EFI is the
1076 bootloader. Note 2TB partition limit; see
1078 CONFIG_MTD_PARTITIONS Memory Technology Device partition table.
1080 If IDE or SCSI support is enabled (CONFIG_IDE or
1081 CONFIG_SCSI) you must configure support for at
1082 least one non-MTD partition type as well.
1085 CONFIG_IDE_RESET_ROUTINE - this is defined in several
1086 board configurations files but used nowhere!
1088 CONFIG_IDE_RESET - is this is defined, IDE Reset will
1089 be performed by calling the function
1090 ide_set_reset(int reset)
1091 which has to be defined in a board specific file
1096 Set this to enable ATAPI support.
1101 Set this to enable support for disks larger than 137GB
1102 Also look at CONFIG_SYS_64BIT_LBA.
1103 Whithout these , LBA48 support uses 32bit variables and will 'only'
1104 support disks up to 2.1TB.
1106 CONFIG_SYS_64BIT_LBA:
1107 When enabled, makes the IDE subsystem use 64bit sector addresses.
1111 At the moment only there is only support for the
1112 SYM53C8XX SCSI controller; define
1113 CONFIG_SCSI_SYM53C8XX to enable it.
1115 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
1116 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
1117 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
1118 maximum numbers of LUNs, SCSI ID's and target
1120 CONFIG_SYS_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
1122 The environment variable 'scsidevs' is set to the number of
1123 SCSI devices found during the last scan.
1125 - NETWORK Support (PCI):
1127 Support for Intel 8254x/8257x gigabit chips.
1130 Utility code for direct access to the SPI bus on Intel 8257x.
1131 This does not do anything useful unless you set at least one
1132 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
1134 CONFIG_E1000_SPI_GENERIC
1135 Allow generic access to the SPI bus on the Intel 8257x, for
1136 example with the "sspi" command.
1139 Management command for E1000 devices. When used on devices
1140 with SPI support you can reprogram the EEPROM from U-Boot.
1143 Support for Intel 82557/82559/82559ER chips.
1144 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
1145 write routine for first time initialisation.
1148 Support for Digital 2114x chips.
1149 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
1150 modem chip initialisation (KS8761/QS6611).
1153 Support for National dp83815 chips.
1156 Support for National dp8382[01] gigabit chips.
1158 - NETWORK Support (other):
1160 CONFIG_DRIVER_AT91EMAC
1161 Support for AT91RM9200 EMAC.
1164 Define this to use reduced MII inteface
1166 CONFIG_DRIVER_AT91EMAC_QUIET
1167 If this defined, the driver is quiet.
1168 The driver doen't show link status messages.
1170 CONFIG_CALXEDA_XGMAC
1171 Support for the Calxeda XGMAC device
1174 Support for SMSC's LAN91C96 chips.
1176 CONFIG_LAN91C96_USE_32_BIT
1177 Define this to enable 32 bit addressing
1180 Support for SMSC's LAN91C111 chip
1182 CONFIG_SMC91111_BASE
1183 Define this to hold the physical address
1184 of the device (I/O space)
1186 CONFIG_SMC_USE_32_BIT
1187 Define this if data bus is 32 bits
1189 CONFIG_SMC_USE_IOFUNCS
1190 Define this to use i/o functions instead of macros
1191 (some hardware wont work with macros)
1193 CONFIG_DRIVER_TI_EMAC
1194 Support for davinci emac
1196 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
1197 Define this if you have more then 3 PHYs.
1200 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
1202 CONFIG_FTGMAC100_EGIGA
1203 Define this to use GE link update with gigabit PHY.
1204 Define this if FTGMAC100 is connected to gigabit PHY.
1205 If your system has 10/100 PHY only, it might not occur
1206 wrong behavior. Because PHY usually return timeout or
1207 useless data when polling gigabit status and gigabit
1208 control registers. This behavior won't affect the
1209 correctnessof 10/100 link speed update.
1212 Support for SMSC's LAN911x and LAN921x chips
1215 Define this to hold the physical address
1216 of the device (I/O space)
1218 CONFIG_SMC911X_32_BIT
1219 Define this if data bus is 32 bits
1221 CONFIG_SMC911X_16_BIT
1222 Define this if data bus is 16 bits. If your processor
1223 automatically converts one 32 bit word to two 16 bit
1224 words you may also try CONFIG_SMC911X_32_BIT.
1227 Support for Renesas on-chip Ethernet controller
1229 CONFIG_SH_ETHER_USE_PORT
1230 Define the number of ports to be used
1232 CONFIG_SH_ETHER_PHY_ADDR
1233 Define the ETH PHY's address
1235 CONFIG_SH_ETHER_CACHE_WRITEBACK
1236 If this option is set, the driver enables cache flush.
1240 Support for PWM module on the imx6.
1244 Support TPM devices.
1246 CONFIG_TPM_TIS_INFINEON
1247 Support for Infineon i2c bus TPM devices. Only one device
1248 per system is supported at this time.
1250 CONFIG_TPM_TIS_I2C_BURST_LIMITATION
1251 Define the burst count bytes upper limit
1254 Support for STMicroelectronics TPM devices. Requires DM_TPM support.
1256 CONFIG_TPM_ST33ZP24_I2C
1257 Support for STMicroelectronics ST33ZP24 I2C devices.
1258 Requires TPM_ST33ZP24 and I2C.
1260 CONFIG_TPM_ST33ZP24_SPI
1261 Support for STMicroelectronics ST33ZP24 SPI devices.
1262 Requires TPM_ST33ZP24 and SPI.
1264 CONFIG_TPM_ATMEL_TWI
1265 Support for Atmel TWI TPM device. Requires I2C support.
1268 Support for generic parallel port TPM devices. Only one device
1269 per system is supported at this time.
1271 CONFIG_TPM_TIS_BASE_ADDRESS
1272 Base address where the generic TPM device is mapped
1273 to. Contemporary x86 systems usually map it at
1277 Add tpm monitor functions.
1278 Requires CONFIG_TPM. If CONFIG_TPM_AUTH_SESSIONS is set, also
1279 provides monitor access to authorized functions.
1282 Define this to enable the TPM support library which provides
1283 functional interfaces to some TPM commands.
1284 Requires support for a TPM device.
1286 CONFIG_TPM_AUTH_SESSIONS
1287 Define this to enable authorized functions in the TPM library.
1288 Requires CONFIG_TPM and CONFIG_SHA1.
1291 At the moment only the UHCI host controller is
1292 supported (PIP405, MIP405, MPC5200); define
1293 CONFIG_USB_UHCI to enable it.
1294 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
1295 and define CONFIG_USB_STORAGE to enable the USB
1298 Supported are USB Keyboards and USB Floppy drives
1300 MPC5200 USB requires additional defines:
1302 for 528 MHz Clock: 0x0001bbbb
1306 for differential drivers: 0x00001000
1307 for single ended drivers: 0x00005000
1308 for differential drivers on PSC3: 0x00000100
1309 for single ended drivers on PSC3: 0x00004100
1310 CONFIG_SYS_USB_EVENT_POLL
1311 May be defined to allow interrupt polling
1312 instead of using asynchronous interrupts
1314 CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
1315 txfilltuning field in the EHCI controller on reset.
1317 CONFIG_USB_DWC2_REG_ADDR the physical CPU address of the DWC2
1318 HW module registers.
1321 Define the below if you wish to use the USB console.
1322 Once firmware is rebuilt from a serial console issue the
1323 command "setenv stdin usbtty; setenv stdout usbtty" and
1324 attach your USB cable. The Unix command "dmesg" should print
1325 it has found a new device. The environment variable usbtty
1326 can be set to gserial or cdc_acm to enable your device to
1327 appear to a USB host as a Linux gserial device or a
1328 Common Device Class Abstract Control Model serial device.
1329 If you select usbtty = gserial you should be able to enumerate
1331 # modprobe usbserial vendor=0xVendorID product=0xProductID
1332 else if using cdc_acm, simply setting the environment
1333 variable usbtty to be cdc_acm should suffice. The following
1334 might be defined in YourBoardName.h
1337 Define this to build a UDC device
1340 Define this to have a tty type of device available to
1341 talk to the UDC device
1344 Define this to enable the high speed support for usb
1345 device and usbtty. If this feature is enabled, a routine
1346 int is_usbd_high_speed(void)
1347 also needs to be defined by the driver to dynamically poll
1348 whether the enumeration has succeded at high speed or full
1351 CONFIG_SYS_CONSOLE_IS_IN_ENV
1352 Define this if you want stdin, stdout &/or stderr to
1356 CONFIG_SYS_USB_EXTC_CLK 0xBLAH
1357 Derive USB clock from external clock "blah"
1358 - CONFIG_SYS_USB_EXTC_CLK 0x02
1360 If you have a USB-IF assigned VendorID then you may wish to
1361 define your own vendor specific values either in BoardName.h
1362 or directly in usbd_vendor_info.h. If you don't define
1363 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
1364 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
1365 should pretend to be a Linux device to it's target host.
1367 CONFIG_USBD_MANUFACTURER
1368 Define this string as the name of your company for
1369 - CONFIG_USBD_MANUFACTURER "my company"
1371 CONFIG_USBD_PRODUCT_NAME
1372 Define this string as the name of your product
1373 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
1375 CONFIG_USBD_VENDORID
1376 Define this as your assigned Vendor ID from the USB
1377 Implementors Forum. This *must* be a genuine Vendor ID
1378 to avoid polluting the USB namespace.
1379 - CONFIG_USBD_VENDORID 0xFFFF
1381 CONFIG_USBD_PRODUCTID
1382 Define this as the unique Product ID
1384 - CONFIG_USBD_PRODUCTID 0xFFFF
1386 - ULPI Layer Support:
1387 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
1388 the generic ULPI layer. The generic layer accesses the ULPI PHY
1389 via the platform viewport, so you need both the genric layer and
1390 the viewport enabled. Currently only Chipidea/ARC based
1391 viewport is supported.
1392 To enable the ULPI layer support, define CONFIG_USB_ULPI and
1393 CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
1394 If your ULPI phy needs a different reference clock than the
1395 standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to
1396 the appropriate value in Hz.
1399 The MMC controller on the Intel PXA is supported. To
1400 enable this define CONFIG_MMC. The MMC can be
1401 accessed from the boot prompt by mapping the device
1402 to physical memory similar to flash. Command line is
1403 enabled with CONFIG_CMD_MMC. The MMC driver also works with
1404 the FAT fs. This is enabled with CONFIG_CMD_FAT.
1407 Support for Renesas on-chip MMCIF controller
1409 CONFIG_SH_MMCIF_ADDR
1410 Define the base address of MMCIF registers
1413 Define the clock frequency for MMCIF
1415 CONFIG_SUPPORT_EMMC_BOOT
1416 Enable some additional features of the eMMC boot partitions.
1418 CONFIG_SUPPORT_EMMC_RPMB
1419 Enable the commands for reading, writing and programming the
1420 key for the Replay Protection Memory Block partition in eMMC.
1422 - USB Device Firmware Update (DFU) class support:
1423 CONFIG_USB_FUNCTION_DFU
1424 This enables the USB portion of the DFU USB class
1427 This enables the command "dfu" which is used to have
1428 U-Boot create a DFU class device via USB. This command
1429 requires that the "dfu_alt_info" environment variable be
1430 set and define the alt settings to expose to the host.
1433 This enables support for exposing (e)MMC devices via DFU.
1436 This enables support for exposing NAND devices via DFU.
1439 This enables support for exposing RAM via DFU.
1440 Note: DFU spec refer to non-volatile memory usage, but
1441 allow usages beyond the scope of spec - here RAM usage,
1442 one that would help mostly the developer.
1444 CONFIG_SYS_DFU_DATA_BUF_SIZE
1445 Dfu transfer uses a buffer before writing data to the
1446 raw storage device. Make the size (in bytes) of this buffer
1447 configurable. The size of this buffer is also configurable
1448 through the "dfu_bufsiz" environment variable.
1450 CONFIG_SYS_DFU_MAX_FILE_SIZE
1451 When updating files rather than the raw storage device,
1452 we use a static buffer to copy the file into and then write
1453 the buffer once we've been given the whole file. Define
1454 this to the maximum filesize (in bytes) for the buffer.
1455 Default is 4 MiB if undefined.
1457 DFU_DEFAULT_POLL_TIMEOUT
1458 Poll timeout [ms], is the timeout a device can send to the
1459 host. The host must wait for this timeout before sending
1460 a subsequent DFU_GET_STATUS request to the device.
1462 DFU_MANIFEST_POLL_TIMEOUT
1463 Poll timeout [ms], which the device sends to the host when
1464 entering dfuMANIFEST state. Host waits this timeout, before
1465 sending again an USB request to the device.
1467 - USB Device Android Fastboot support:
1468 CONFIG_USB_FUNCTION_FASTBOOT
1469 This enables the USB part of the fastboot gadget
1472 This enables the command "fastboot" which enables the Android
1473 fastboot mode for the platform's USB device. Fastboot is a USB
1474 protocol for downloading images, flashing and device control
1475 used on Android devices.
1476 See doc/README.android-fastboot for more information.
1478 CONFIG_ANDROID_BOOT_IMAGE
1479 This enables support for booting images which use the Android
1480 image format header.
1482 CONFIG_FASTBOOT_BUF_ADDR
1483 The fastboot protocol requires a large memory buffer for
1484 downloads. Define this to the starting RAM address to use for
1487 CONFIG_FASTBOOT_BUF_SIZE
1488 The fastboot protocol requires a large memory buffer for
1489 downloads. This buffer should be as large as possible for a
1490 platform. Define this to the size available RAM for fastboot.
1492 CONFIG_FASTBOOT_FLASH
1493 The fastboot protocol includes a "flash" command for writing
1494 the downloaded image to a non-volatile storage device. Define
1495 this to enable the "fastboot flash" command.
1497 CONFIG_FASTBOOT_FLASH_MMC_DEV
1498 The fastboot "flash" command requires additional information
1499 regarding the non-volatile storage device. Define this to
1500 the eMMC device that fastboot should use to store the image.
1502 CONFIG_FASTBOOT_GPT_NAME
1503 The fastboot "flash" command supports writing the downloaded
1504 image to the Protective MBR and the Primary GUID Partition
1505 Table. (Additionally, this downloaded image is post-processed
1506 to generate and write the Backup GUID Partition Table.)
1507 This occurs when the specified "partition name" on the
1508 "fastboot flash" command line matches this value.
1509 The default is "gpt" if undefined.
1511 CONFIG_FASTBOOT_MBR_NAME
1512 The fastboot "flash" command supports writing the downloaded
1514 This occurs when the "partition name" specified on the
1515 "fastboot flash" command line matches this value.
1516 If not defined the default value "mbr" is used.
1518 - Journaling Flash filesystem support:
1520 Define these for a default partition on a NAND device
1522 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1523 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1524 Define these for a default partition on a NOR device
1526 - FAT(File Allocation Table) filesystem write function support:
1529 Define this to enable support for saving memory data as a
1530 file in FAT formatted partition.
1532 This will also enable the command "fatwrite" enabling the
1533 user to write files to FAT.
1535 - FAT(File Allocation Table) filesystem cluster size:
1536 CONFIG_FS_FAT_MAX_CLUSTSIZE
1538 Define the max cluster size for fat operations else
1539 a default value of 65536 will be defined.
1542 See Kconfig help for available keyboard drivers.
1546 Define this to enable a custom keyboard support.
1547 This simply calls drv_keyboard_init() which must be
1548 defined in your board-specific files. This option is deprecated
1549 and is only used by novena. For new boards, use driver model
1554 Enable the Freescale DIU video driver. Reference boards for
1555 SOCs that have a DIU should define this macro to enable DIU
1556 support, and should also define these other macros:
1561 CONFIG_VIDEO_SW_CURSOR
1562 CONFIG_VGA_AS_SINGLE_DEVICE
1564 CONFIG_VIDEO_BMP_LOGO
1566 The DIU driver will look for the 'video-mode' environment
1567 variable, and if defined, enable the DIU as a console during
1568 boot. See the documentation file doc/README.video for a
1569 description of this variable.
1571 - LCD Support: CONFIG_LCD
1573 Define this to enable LCD support (for output to LCD
1574 display); also select one of the supported displays
1575 by defining one of these:
1579 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1581 CONFIG_NEC_NL6448AC33:
1583 NEC NL6448AC33-18. Active, color, single scan.
1585 CONFIG_NEC_NL6448BC20
1587 NEC NL6448BC20-08. 6.5", 640x480.
1588 Active, color, single scan.
1590 CONFIG_NEC_NL6448BC33_54
1592 NEC NL6448BC33-54. 10.4", 640x480.
1593 Active, color, single scan.
1597 Sharp 320x240. Active, color, single scan.
1598 It isn't 16x9, and I am not sure what it is.
1600 CONFIG_SHARP_LQ64D341
1602 Sharp LQ64D341 display, 640x480.
1603 Active, color, single scan.
1607 HLD1045 display, 640x480.
1608 Active, color, single scan.
1612 Optrex CBL50840-2 NF-FW 99 22 M5
1614 Hitachi LMG6912RPFC-00T
1618 320x240. Black & white.
1620 CONFIG_LCD_ALIGNMENT
1622 Normally the LCD is page-aligned (typically 4KB). If this is
1623 defined then the LCD will be aligned to this value instead.
1624 For ARM it is sometimes useful to use MMU_SECTION_SIZE
1625 here, since it is cheaper to change data cache settings on
1626 a per-section basis.
1631 Sometimes, for example if the display is mounted in portrait
1632 mode or even if it's mounted landscape but rotated by 180degree,
1633 we need to rotate our content of the display relative to the
1634 framebuffer, so that user can read the messages which are
1636 Once CONFIG_LCD_ROTATION is defined, the lcd_console will be
1637 initialized with a given rotation from "vl_rot" out of
1638 "vidinfo_t" which is provided by the board specific code.
1639 The value for vl_rot is coded as following (matching to
1640 fbcon=rotate:<n> linux-kernel commandline):
1641 0 = no rotation respectively 0 degree
1642 1 = 90 degree rotation
1643 2 = 180 degree rotation
1644 3 = 270 degree rotation
1646 If CONFIG_LCD_ROTATION is not defined, the console will be
1647 initialized with 0degree rotation.
1651 Support drawing of RLE8-compressed bitmaps on the LCD.
1655 Enables an 'i2c edid' command which can read EDID
1656 information over I2C from an attached LCD display.
1658 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1660 If this option is set, the environment is checked for
1661 a variable "splashimage". If found, the usual display
1662 of logo, copyright and system information on the LCD
1663 is suppressed and the BMP image at the address
1664 specified in "splashimage" is loaded instead. The
1665 console is redirected to the "nulldev", too. This
1666 allows for a "silent" boot where a splash screen is
1667 loaded very quickly after power-on.
1669 CONFIG_SPLASHIMAGE_GUARD
1671 If this option is set, then U-Boot will prevent the environment
1672 variable "splashimage" from being set to a problematic address
1673 (see doc/README.displaying-bmps).
1674 This option is useful for targets where, due to alignment
1675 restrictions, an improperly aligned BMP image will cause a data
1676 abort. If you think you will not have problems with unaligned
1677 accesses (for example because your toolchain prevents them)
1678 there is no need to set this option.
1680 CONFIG_SPLASH_SCREEN_ALIGN
1682 If this option is set the splash image can be freely positioned
1683 on the screen. Environment variable "splashpos" specifies the
1684 position as "x,y". If a positive number is given it is used as
1685 number of pixel from left/top. If a negative number is given it
1686 is used as number of pixel from right/bottom. You can also
1687 specify 'm' for centering the image.
1690 setenv splashpos m,m
1691 => image at center of screen
1693 setenv splashpos 30,20
1694 => image at x = 30 and y = 20
1696 setenv splashpos -10,m
1697 => vertically centered image
1698 at x = dspWidth - bmpWidth - 9
1700 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1702 If this option is set, additionally to standard BMP
1703 images, gzipped BMP images can be displayed via the
1704 splashscreen support or the bmp command.
1706 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1708 If this option is set, 8-bit RLE compressed BMP images
1709 can be displayed via the splashscreen support or the
1712 - Compression support:
1715 Enabled by default to support gzip compressed images.
1719 If this option is set, support for bzip2 compressed
1720 images is included. If not, only uncompressed and gzip
1721 compressed images are supported.
1723 NOTE: the bzip2 algorithm requires a lot of RAM, so
1724 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1729 If this option is set, support for lzma compressed
1732 Note: The LZMA algorithm adds between 2 and 4KB of code and it
1733 requires an amount of dynamic memory that is given by the
1736 (1846 + 768 << (lc + lp)) * sizeof(uint16)
1738 Where lc and lp stand for, respectively, Literal context bits
1739 and Literal pos bits.
1741 This value is upper-bounded by 14MB in the worst case. Anyway,
1742 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
1743 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
1744 a very small buffer.
1746 Use the lzmainfo tool to determinate the lc and lp values and
1747 then calculate the amount of needed dynamic memory (ensuring
1748 the appropriate CONFIG_SYS_MALLOC_LEN value).
1752 If this option is set, support for LZO compressed images
1758 The address of PHY on MII bus.
1760 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1762 The clock frequency of the MII bus
1766 If this option is set, support for speed/duplex
1767 detection of gigabit PHY is included.
1769 CONFIG_PHY_RESET_DELAY
1771 Some PHY like Intel LXT971A need extra delay after
1772 reset before any MII register access is possible.
1773 For such PHY, set this option to the usec delay
1774 required. (minimum 300usec for LXT971A)
1776 CONFIG_PHY_CMD_DELAY (ppc4xx)
1778 Some PHY like Intel LXT971A need extra delay after
1779 command issued before MII status register can be read
1784 Define a default value for the IP address to use for
1785 the default Ethernet interface, in case this is not
1786 determined through e.g. bootp.
1787 (Environment variable "ipaddr")
1789 - Server IP address:
1792 Defines a default value for the IP address of a TFTP
1793 server to contact when using the "tftboot" command.
1794 (Environment variable "serverip")
1796 CONFIG_KEEP_SERVERADDR
1798 Keeps the server's MAC address, in the env 'serveraddr'
1799 for passing to bootargs (like Linux's netconsole option)
1801 - Gateway IP address:
1804 Defines a default value for the IP address of the
1805 default router where packets to other networks are
1807 (Environment variable "gatewayip")
1812 Defines a default value for the subnet mask (or
1813 routing prefix) which is used to determine if an IP
1814 address belongs to the local subnet or needs to be
1815 forwarded through a router.
1816 (Environment variable "netmask")
1818 - Multicast TFTP Mode:
1821 Defines whether you want to support multicast TFTP as per
1822 rfc-2090; for example to work with atftp. Lets lots of targets
1823 tftp down the same boot image concurrently. Note: the Ethernet
1824 driver in use must provide a function: mcast() to join/leave a
1827 - BOOTP Recovery Mode:
1828 CONFIG_BOOTP_RANDOM_DELAY
1830 If you have many targets in a network that try to
1831 boot using BOOTP, you may want to avoid that all
1832 systems send out BOOTP requests at precisely the same
1833 moment (which would happen for instance at recovery
1834 from a power failure, when all systems will try to
1835 boot, thus flooding the BOOTP server. Defining
1836 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1837 inserted before sending out BOOTP requests. The
1838 following delays are inserted then:
1840 1st BOOTP request: delay 0 ... 1 sec
1841 2nd BOOTP request: delay 0 ... 2 sec
1842 3rd BOOTP request: delay 0 ... 4 sec
1844 BOOTP requests: delay 0 ... 8 sec
1846 CONFIG_BOOTP_ID_CACHE_SIZE
1848 BOOTP packets are uniquely identified using a 32-bit ID. The
1849 server will copy the ID from client requests to responses and
1850 U-Boot will use this to determine if it is the destination of
1851 an incoming response. Some servers will check that addresses
1852 aren't in use before handing them out (usually using an ARP
1853 ping) and therefore take up to a few hundred milliseconds to
1854 respond. Network congestion may also influence the time it
1855 takes for a response to make it back to the client. If that
1856 time is too long, U-Boot will retransmit requests. In order
1857 to allow earlier responses to still be accepted after these
1858 retransmissions, U-Boot's BOOTP client keeps a small cache of
1859 IDs. The CONFIG_BOOTP_ID_CACHE_SIZE controls the size of this
1860 cache. The default is to keep IDs for up to four outstanding
1861 requests. Increasing this will allow U-Boot to accept offers
1862 from a BOOTP client in networks with unusually high latency.
1864 - DHCP Advanced Options:
1865 You can fine tune the DHCP functionality by defining
1866 CONFIG_BOOTP_* symbols:
1868 CONFIG_BOOTP_SUBNETMASK
1869 CONFIG_BOOTP_GATEWAY
1870 CONFIG_BOOTP_HOSTNAME
1871 CONFIG_BOOTP_NISDOMAIN
1872 CONFIG_BOOTP_BOOTPATH
1873 CONFIG_BOOTP_BOOTFILESIZE
1876 CONFIG_BOOTP_SEND_HOSTNAME
1877 CONFIG_BOOTP_NTPSERVER
1878 CONFIG_BOOTP_TIMEOFFSET
1879 CONFIG_BOOTP_VENDOREX
1880 CONFIG_BOOTP_MAY_FAIL
1882 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1883 environment variable, not the BOOTP server.
1885 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
1886 after the configured retry count, the call will fail
1887 instead of starting over. This can be used to fail over
1888 to Link-local IP address configuration if the DHCP server
1891 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1892 serverip from a DHCP server, it is possible that more
1893 than one DNS serverip is offered to the client.
1894 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1895 serverip will be stored in the additional environment
1896 variable "dnsip2". The first DNS serverip is always
1897 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1900 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1901 to do a dynamic update of a DNS server. To do this, they
1902 need the hostname of the DHCP requester.
1903 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1904 of the "hostname" environment variable is passed as
1905 option 12 to the DHCP server.
1907 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1909 A 32bit value in microseconds for a delay between
1910 receiving a "DHCP Offer" and sending the "DHCP Request".
1911 This fixes a problem with certain DHCP servers that don't
1912 respond 100% of the time to a "DHCP request". E.g. On an
1913 AT91RM9200 processor running at 180MHz, this delay needed
1914 to be *at least* 15,000 usec before a Windows Server 2003
1915 DHCP server would reply 100% of the time. I recommend at
1916 least 50,000 usec to be safe. The alternative is to hope
1917 that one of the retries will be successful but note that
1918 the DHCP timeout and retry process takes a longer than
1921 - Link-local IP address negotiation:
1922 Negotiate with other link-local clients on the local network
1923 for an address that doesn't require explicit configuration.
1924 This is especially useful if a DHCP server cannot be guaranteed
1925 to exist in all environments that the device must operate.
1927 See doc/README.link-local for more information.
1930 CONFIG_CDP_DEVICE_ID
1932 The device id used in CDP trigger frames.
1934 CONFIG_CDP_DEVICE_ID_PREFIX
1936 A two character string which is prefixed to the MAC address
1941 A printf format string which contains the ascii name of
1942 the port. Normally is set to "eth%d" which sets
1943 eth0 for the first Ethernet, eth1 for the second etc.
1945 CONFIG_CDP_CAPABILITIES
1947 A 32bit integer which indicates the device capabilities;
1948 0x00000010 for a normal host which does not forwards.
1952 An ascii string containing the version of the software.
1956 An ascii string containing the name of the platform.
1960 A 32bit integer sent on the trigger.
1962 CONFIG_CDP_POWER_CONSUMPTION
1964 A 16bit integer containing the power consumption of the
1965 device in .1 of milliwatts.
1967 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1969 A byte containing the id of the VLAN.
1971 - Status LED: CONFIG_LED_STATUS
1973 Several configurations allow to display the current
1974 status using a LED. For instance, the LED will blink
1975 fast while running U-Boot code, stop blinking as
1976 soon as a reply to a BOOTP request was received, and
1977 start blinking slow once the Linux kernel is running
1978 (supported by a status LED driver in the Linux
1979 kernel). Defining CONFIG_LED_STATUS enables this
1984 CONFIG_LED_STATUS_GPIO
1985 The status LED can be connected to a GPIO pin.
1986 In such cases, the gpio_led driver can be used as a
1987 status LED backend implementation. Define CONFIG_LED_STATUS_GPIO
1988 to include the gpio_led driver in the U-Boot binary.
1990 CONFIG_GPIO_LED_INVERTED_TABLE
1991 Some GPIO connected LEDs may have inverted polarity in which
1992 case the GPIO high value corresponds to LED off state and
1993 GPIO low value corresponds to LED on state.
1994 In such cases CONFIG_GPIO_LED_INVERTED_TABLE may be defined
1995 with a list of GPIO LEDs that have inverted polarity.
1997 - CAN Support: CONFIG_CAN_DRIVER
1999 Defining CONFIG_CAN_DRIVER enables CAN driver support
2000 on those systems that support this (optional)
2001 feature, like the TQM8xxL modules.
2003 - I2C Support: CONFIG_SYS_I2C
2005 This enable the NEW i2c subsystem, and will allow you to use
2006 i2c commands at the u-boot command line (as long as you set
2007 CONFIG_CMD_I2C in CONFIG_COMMANDS) and communicate with i2c
2008 based realtime clock chips or other i2c devices. See
2009 common/cmd_i2c.c for a description of the command line
2012 ported i2c driver to the new framework:
2013 - drivers/i2c/soft_i2c.c:
2014 - activate first bus with CONFIG_SYS_I2C_SOFT define
2015 CONFIG_SYS_I2C_SOFT_SPEED and CONFIG_SYS_I2C_SOFT_SLAVE
2016 for defining speed and slave address
2017 - activate second bus with I2C_SOFT_DECLARATIONS2 define
2018 CONFIG_SYS_I2C_SOFT_SPEED_2 and CONFIG_SYS_I2C_SOFT_SLAVE_2
2019 for defining speed and slave address
2020 - activate third bus with I2C_SOFT_DECLARATIONS3 define
2021 CONFIG_SYS_I2C_SOFT_SPEED_3 and CONFIG_SYS_I2C_SOFT_SLAVE_3
2022 for defining speed and slave address
2023 - activate fourth bus with I2C_SOFT_DECLARATIONS4 define
2024 CONFIG_SYS_I2C_SOFT_SPEED_4 and CONFIG_SYS_I2C_SOFT_SLAVE_4
2025 for defining speed and slave address
2027 - drivers/i2c/fsl_i2c.c:
2028 - activate i2c driver with CONFIG_SYS_I2C_FSL
2029 define CONFIG_SYS_FSL_I2C_OFFSET for setting the register
2030 offset CONFIG_SYS_FSL_I2C_SPEED for the i2c speed and
2031 CONFIG_SYS_FSL_I2C_SLAVE for the slave addr of the first
2033 - If your board supports a second fsl i2c bus, define
2034 CONFIG_SYS_FSL_I2C2_OFFSET for the register offset
2035 CONFIG_SYS_FSL_I2C2_SPEED for the speed and
2036 CONFIG_SYS_FSL_I2C2_SLAVE for the slave address of the
2039 - drivers/i2c/tegra_i2c.c:
2040 - activate this driver with CONFIG_SYS_I2C_TEGRA
2041 - This driver adds 4 i2c buses with a fix speed from
2042 100000 and the slave addr 0!
2044 - drivers/i2c/ppc4xx_i2c.c
2045 - activate this driver with CONFIG_SYS_I2C_PPC4XX
2046 - CONFIG_SYS_I2C_PPC4XX_CH0 activate hardware channel 0
2047 - CONFIG_SYS_I2C_PPC4XX_CH1 activate hardware channel 1
2049 - drivers/i2c/i2c_mxc.c
2050 - activate this driver with CONFIG_SYS_I2C_MXC
2051 - enable bus 1 with CONFIG_SYS_I2C_MXC_I2C1
2052 - enable bus 2 with CONFIG_SYS_I2C_MXC_I2C2
2053 - enable bus 3 with CONFIG_SYS_I2C_MXC_I2C3
2054 - enable bus 4 with CONFIG_SYS_I2C_MXC_I2C4
2055 - define speed for bus 1 with CONFIG_SYS_MXC_I2C1_SPEED
2056 - define slave for bus 1 with CONFIG_SYS_MXC_I2C1_SLAVE
2057 - define speed for bus 2 with CONFIG_SYS_MXC_I2C2_SPEED
2058 - define slave for bus 2 with CONFIG_SYS_MXC_I2C2_SLAVE
2059 - define speed for bus 3 with CONFIG_SYS_MXC_I2C3_SPEED
2060 - define slave for bus 3 with CONFIG_SYS_MXC_I2C3_SLAVE
2061 - define speed for bus 4 with CONFIG_SYS_MXC_I2C4_SPEED
2062 - define slave for bus 4 with CONFIG_SYS_MXC_I2C4_SLAVE
2063 If those defines are not set, default value is 100000
2064 for speed, and 0 for slave.
2066 - drivers/i2c/rcar_i2c.c:
2067 - activate this driver with CONFIG_SYS_I2C_RCAR
2068 - This driver adds 4 i2c buses
2070 - CONFIG_SYS_RCAR_I2C0_BASE for setting the register channel 0
2071 - CONFIG_SYS_RCAR_I2C0_SPEED for for the speed channel 0
2072 - CONFIG_SYS_RCAR_I2C1_BASE for setting the register channel 1
2073 - CONFIG_SYS_RCAR_I2C1_SPEED for for the speed channel 1
2074 - CONFIG_SYS_RCAR_I2C2_BASE for setting the register channel 2
2075 - CONFIG_SYS_RCAR_I2C2_SPEED for for the speed channel 2
2076 - CONFIG_SYS_RCAR_I2C3_BASE for setting the register channel 3
2077 - CONFIG_SYS_RCAR_I2C3_SPEED for for the speed channel 3
2078 - CONFIF_SYS_RCAR_I2C_NUM_CONTROLLERS for number of i2c buses
2080 - drivers/i2c/sh_i2c.c:
2081 - activate this driver with CONFIG_SYS_I2C_SH
2082 - This driver adds from 2 to 5 i2c buses
2084 - CONFIG_SYS_I2C_SH_BASE0 for setting the register channel 0
2085 - CONFIG_SYS_I2C_SH_SPEED0 for for the speed channel 0
2086 - CONFIG_SYS_I2C_SH_BASE1 for setting the register channel 1
2087 - CONFIG_SYS_I2C_SH_SPEED1 for for the speed channel 1
2088 - CONFIG_SYS_I2C_SH_BASE2 for setting the register channel 2
2089 - CONFIG_SYS_I2C_SH_SPEED2 for for the speed channel 2
2090 - CONFIG_SYS_I2C_SH_BASE3 for setting the register channel 3
2091 - CONFIG_SYS_I2C_SH_SPEED3 for for the speed channel 3
2092 - CONFIG_SYS_I2C_SH_BASE4 for setting the register channel 4
2093 - CONFIG_SYS_I2C_SH_SPEED4 for for the speed channel 4
2094 - CONFIG_SYS_I2C_SH_NUM_CONTROLLERS for number of i2c buses
2096 - drivers/i2c/omap24xx_i2c.c
2097 - activate this driver with CONFIG_SYS_I2C_OMAP24XX
2098 - CONFIG_SYS_OMAP24_I2C_SPEED speed channel 0
2099 - CONFIG_SYS_OMAP24_I2C_SLAVE slave addr channel 0
2100 - CONFIG_SYS_OMAP24_I2C_SPEED1 speed channel 1
2101 - CONFIG_SYS_OMAP24_I2C_SLAVE1 slave addr channel 1
2102 - CONFIG_SYS_OMAP24_I2C_SPEED2 speed channel 2
2103 - CONFIG_SYS_OMAP24_I2C_SLAVE2 slave addr channel 2
2104 - CONFIG_SYS_OMAP24_I2C_SPEED3 speed channel 3
2105 - CONFIG_SYS_OMAP24_I2C_SLAVE3 slave addr channel 3
2106 - CONFIG_SYS_OMAP24_I2C_SPEED4 speed channel 4
2107 - CONFIG_SYS_OMAP24_I2C_SLAVE4 slave addr channel 4
2109 - drivers/i2c/zynq_i2c.c
2110 - activate this driver with CONFIG_SYS_I2C_ZYNQ
2111 - set CONFIG_SYS_I2C_ZYNQ_SPEED for speed setting
2112 - set CONFIG_SYS_I2C_ZYNQ_SLAVE for slave addr
2114 - drivers/i2c/s3c24x0_i2c.c:
2115 - activate this driver with CONFIG_SYS_I2C_S3C24X0
2116 - This driver adds i2c buses (11 for Exynos5250, Exynos5420
2117 9 i2c buses for Exynos4 and 1 for S3C24X0 SoCs from Samsung)
2118 with a fix speed from 100000 and the slave addr 0!
2120 - drivers/i2c/ihs_i2c.c
2121 - activate this driver with CONFIG_SYS_I2C_IHS
2122 - CONFIG_SYS_I2C_IHS_CH0 activate hardware channel 0
2123 - CONFIG_SYS_I2C_IHS_SPEED_0 speed channel 0
2124 - CONFIG_SYS_I2C_IHS_SLAVE_0 slave addr channel 0
2125 - CONFIG_SYS_I2C_IHS_CH1 activate hardware channel 1
2126 - CONFIG_SYS_I2C_IHS_SPEED_1 speed channel 1
2127 - CONFIG_SYS_I2C_IHS_SLAVE_1 slave addr channel 1
2128 - CONFIG_SYS_I2C_IHS_CH2 activate hardware channel 2
2129 - CONFIG_SYS_I2C_IHS_SPEED_2 speed channel 2
2130 - CONFIG_SYS_I2C_IHS_SLAVE_2 slave addr channel 2
2131 - CONFIG_SYS_I2C_IHS_CH3 activate hardware channel 3
2132 - CONFIG_SYS_I2C_IHS_SPEED_3 speed channel 3
2133 - CONFIG_SYS_I2C_IHS_SLAVE_3 slave addr channel 3
2134 - activate dual channel with CONFIG_SYS_I2C_IHS_DUAL
2135 - CONFIG_SYS_I2C_IHS_SPEED_0_1 speed channel 0_1
2136 - CONFIG_SYS_I2C_IHS_SLAVE_0_1 slave addr channel 0_1
2137 - CONFIG_SYS_I2C_IHS_SPEED_1_1 speed channel 1_1
2138 - CONFIG_SYS_I2C_IHS_SLAVE_1_1 slave addr channel 1_1
2139 - CONFIG_SYS_I2C_IHS_SPEED_2_1 speed channel 2_1
2140 - CONFIG_SYS_I2C_IHS_SLAVE_2_1 slave addr channel 2_1
2141 - CONFIG_SYS_I2C_IHS_SPEED_3_1 speed channel 3_1
2142 - CONFIG_SYS_I2C_IHS_SLAVE_3_1 slave addr channel 3_1
2146 CONFIG_SYS_NUM_I2C_BUSES
2147 Hold the number of i2c buses you want to use.
2149 CONFIG_SYS_I2C_DIRECT_BUS
2150 define this, if you don't use i2c muxes on your hardware.
2151 if CONFIG_SYS_I2C_MAX_HOPS is not defined or == 0 you can
2154 CONFIG_SYS_I2C_MAX_HOPS
2155 define how many muxes are maximal consecutively connected
2156 on one i2c bus. If you not use i2c muxes, omit this
2159 CONFIG_SYS_I2C_BUSES
2160 hold a list of buses you want to use, only used if
2161 CONFIG_SYS_I2C_DIRECT_BUS is not defined, for example
2162 a board with CONFIG_SYS_I2C_MAX_HOPS = 1 and
2163 CONFIG_SYS_NUM_I2C_BUSES = 9:
2165 CONFIG_SYS_I2C_BUSES {{0, {I2C_NULL_HOP}}, \
2166 {0, {{I2C_MUX_PCA9547, 0x70, 1}}}, \
2167 {0, {{I2C_MUX_PCA9547, 0x70, 2}}}, \
2168 {0, {{I2C_MUX_PCA9547, 0x70, 3}}}, \
2169 {0, {{I2C_MUX_PCA9547, 0x70, 4}}}, \
2170 {0, {{I2C_MUX_PCA9547, 0x70, 5}}}, \
2171 {1, {I2C_NULL_HOP}}, \
2172 {1, {{I2C_MUX_PCA9544, 0x72, 1}}}, \
2173 {1, {{I2C_MUX_PCA9544, 0x72, 2}}}, \
2177 bus 0 on adapter 0 without a mux
2178 bus 1 on adapter 0 with a PCA9547 on address 0x70 port 1
2179 bus 2 on adapter 0 with a PCA9547 on address 0x70 port 2
2180 bus 3 on adapter 0 with a PCA9547 on address 0x70 port 3
2181 bus 4 on adapter 0 with a PCA9547 on address 0x70 port 4
2182 bus 5 on adapter 0 with a PCA9547 on address 0x70 port 5
2183 bus 6 on adapter 1 without a mux
2184 bus 7 on adapter 1 with a PCA9544 on address 0x72 port 1
2185 bus 8 on adapter 1 with a PCA9544 on address 0x72 port 2
2187 If you do not have i2c muxes on your board, omit this define.
2189 - Legacy I2C Support:
2190 If you use the software i2c interface (CONFIG_SYS_I2C_SOFT)
2191 then the following macros need to be defined (examples are
2192 from include/configs/lwmon.h):
2196 (Optional). Any commands necessary to enable the I2C
2197 controller or configure ports.
2199 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
2203 (Only for MPC8260 CPU). The I/O port to use (the code
2204 assumes both bits are on the same port). Valid values
2205 are 0..3 for ports A..D.
2209 The code necessary to make the I2C data line active
2210 (driven). If the data line is open collector, this
2213 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
2217 The code necessary to make the I2C data line tri-stated
2218 (inactive). If the data line is open collector, this
2221 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
2225 Code that returns true if the I2C data line is high,
2228 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
2232 If <bit> is true, sets the I2C data line high. If it
2233 is false, it clears it (low).
2235 eg: #define I2C_SDA(bit) \
2236 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
2237 else immr->im_cpm.cp_pbdat &= ~PB_SDA
2241 If <bit> is true, sets the I2C clock line high. If it
2242 is false, it clears it (low).
2244 eg: #define I2C_SCL(bit) \
2245 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
2246 else immr->im_cpm.cp_pbdat &= ~PB_SCL
2250 This delay is invoked four times per clock cycle so this
2251 controls the rate of data transfer. The data rate thus
2252 is 1 / (I2C_DELAY * 4). Often defined to be something
2255 #define I2C_DELAY udelay(2)
2257 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
2259 If your arch supports the generic GPIO framework (asm/gpio.h),
2260 then you may alternatively define the two GPIOs that are to be
2261 used as SCL / SDA. Any of the previous I2C_xxx macros will
2262 have GPIO-based defaults assigned to them as appropriate.
2264 You should define these to the GPIO value as given directly to
2265 the generic GPIO functions.
2267 CONFIG_SYS_I2C_INIT_BOARD
2269 When a board is reset during an i2c bus transfer
2270 chips might think that the current transfer is still
2271 in progress. On some boards it is possible to access
2272 the i2c SCLK line directly, either by using the
2273 processor pin as a GPIO or by having a second pin
2274 connected to the bus. If this option is defined a
2275 custom i2c_init_board() routine in boards/xxx/board.c
2276 is run early in the boot sequence.
2278 CONFIG_I2C_MULTI_BUS
2280 This option allows the use of multiple I2C buses, each of which
2281 must have a controller. At any point in time, only one bus is
2282 active. To switch to a different bus, use the 'i2c dev' command.
2283 Note that bus numbering is zero-based.
2285 CONFIG_SYS_I2C_NOPROBES
2287 This option specifies a list of I2C devices that will be skipped
2288 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
2289 is set, specify a list of bus-device pairs. Otherwise, specify
2290 a 1D array of device addresses
2293 #undef CONFIG_I2C_MULTI_BUS
2294 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
2296 will skip addresses 0x50 and 0x68 on a board with one I2C bus
2298 #define CONFIG_I2C_MULTI_BUS
2299 #define CONFIG_SYS_I2C_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
2301 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
2303 CONFIG_SYS_SPD_BUS_NUM
2305 If defined, then this indicates the I2C bus number for DDR SPD.
2306 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
2308 CONFIG_SYS_RTC_BUS_NUM
2310 If defined, then this indicates the I2C bus number for the RTC.
2311 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
2313 CONFIG_SOFT_I2C_READ_REPEATED_START
2315 defining this will force the i2c_read() function in
2316 the soft_i2c driver to perform an I2C repeated start
2317 between writing the address pointer and reading the
2318 data. If this define is omitted the default behaviour
2319 of doing a stop-start sequence will be used. Most I2C
2320 devices can use either method, but some require one or
2323 - SPI Support: CONFIG_SPI
2325 Enables SPI driver (so far only tested with
2326 SPI EEPROM, also an instance works with Crystal A/D and
2327 D/As on the SACSng board)
2331 Enables the driver for SPI controller on SuperH. Currently
2332 only SH7757 is supported.
2336 Enables a software (bit-bang) SPI driver rather than
2337 using hardware support. This is a general purpose
2338 driver that only requires three general I/O port pins
2339 (two outputs, one input) to function. If this is
2340 defined, the board configuration must define several
2341 SPI configuration items (port pins to use, etc). For
2342 an example, see include/configs/sacsng.h.
2346 Enables a hardware SPI driver for general-purpose reads
2347 and writes. As with CONFIG_SOFT_SPI, the board configuration
2348 must define a list of chip-select function pointers.
2349 Currently supported on some MPC8xxx processors. For an
2350 example, see include/configs/mpc8349emds.h.
2354 Enables the driver for the SPI controllers on i.MX and MXC
2355 SoCs. Currently i.MX31/35/51 are supported.
2357 CONFIG_SYS_SPI_MXC_WAIT
2358 Timeout for waiting until spi transfer completed.
2359 default: (CONFIG_SYS_HZ/100) /* 10 ms */
2361 - FPGA Support: CONFIG_FPGA
2363 Enables FPGA subsystem.
2365 CONFIG_FPGA_<vendor>
2367 Enables support for specific chip vendors.
2370 CONFIG_FPGA_<family>
2372 Enables support for FPGA family.
2373 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
2377 Specify the number of FPGA devices to support.
2379 CONFIG_SYS_FPGA_PROG_FEEDBACK
2381 Enable printing of hash marks during FPGA configuration.
2383 CONFIG_SYS_FPGA_CHECK_BUSY
2385 Enable checks on FPGA configuration interface busy
2386 status by the configuration function. This option
2387 will require a board or device specific function to
2392 If defined, a function that provides delays in the FPGA
2393 configuration driver.
2395 CONFIG_SYS_FPGA_CHECK_CTRLC
2396 Allow Control-C to interrupt FPGA configuration
2398 CONFIG_SYS_FPGA_CHECK_ERROR
2400 Check for configuration errors during FPGA bitfile
2401 loading. For example, abort during Virtex II
2402 configuration if the INIT_B line goes low (which
2403 indicated a CRC error).
2405 CONFIG_SYS_FPGA_WAIT_INIT
2407 Maximum time to wait for the INIT_B line to de-assert
2408 after PROB_B has been de-asserted during a Virtex II
2409 FPGA configuration sequence. The default time is 500
2412 CONFIG_SYS_FPGA_WAIT_BUSY
2414 Maximum time to wait for BUSY to de-assert during
2415 Virtex II FPGA configuration. The default is 5 ms.
2417 CONFIG_SYS_FPGA_WAIT_CONFIG
2419 Time to wait after FPGA configuration. The default is
2422 - Configuration Management:
2425 Some SoCs need special image types (e.g. U-Boot binary
2426 with a special header) as build targets. By defining
2427 CONFIG_BUILD_TARGET in the SoC / board header, this
2428 special image will be automatically built upon calling
2433 If defined, this string will be added to the U-Boot
2434 version information (U_BOOT_VERSION)
2436 - Vendor Parameter Protection:
2438 U-Boot considers the values of the environment
2439 variables "serial#" (Board Serial Number) and
2440 "ethaddr" (Ethernet Address) to be parameters that
2441 are set once by the board vendor / manufacturer, and
2442 protects these variables from casual modification by
2443 the user. Once set, these variables are read-only,
2444 and write or delete attempts are rejected. You can
2445 change this behaviour:
2447 If CONFIG_ENV_OVERWRITE is #defined in your config
2448 file, the write protection for vendor parameters is
2449 completely disabled. Anybody can change or delete
2452 Alternatively, if you define _both_ an ethaddr in the
2453 default env _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2454 Ethernet address is installed in the environment,
2455 which can be changed exactly ONCE by the user. [The
2456 serial# is unaffected by this, i. e. it remains
2459 The same can be accomplished in a more flexible way
2460 for any variable by configuring the type of access
2461 to allow for those variables in the ".flags" variable
2462 or define CONFIG_ENV_FLAGS_LIST_STATIC.
2467 Define this variable to enable the reservation of
2468 "protected RAM", i. e. RAM which is not overwritten
2469 by U-Boot. Define CONFIG_PRAM to hold the number of
2470 kB you want to reserve for pRAM. You can overwrite
2471 this default value by defining an environment
2472 variable "pram" to the number of kB you want to
2473 reserve. Note that the board info structure will
2474 still show the full amount of RAM. If pRAM is
2475 reserved, a new environment variable "mem" will
2476 automatically be defined to hold the amount of
2477 remaining RAM in a form that can be passed as boot
2478 argument to Linux, for instance like that:
2480 setenv bootargs ... mem=\${mem}
2483 This way you can tell Linux not to use this memory,
2484 either, which results in a memory region that will
2485 not be affected by reboots.
2487 *WARNING* If your board configuration uses automatic
2488 detection of the RAM size, you must make sure that
2489 this memory test is non-destructive. So far, the
2490 following board configurations are known to be
2493 IVMS8, IVML24, SPD8xx, TQM8xxL,
2494 HERMES, IP860, RPXlite, LWMON,
2497 - Access to physical memory region (> 4GB)
2498 Some basic support is provided for operations on memory not
2499 normally accessible to U-Boot - e.g. some architectures
2500 support access to more than 4GB of memory on 32-bit
2501 machines using physical address extension or similar.
2502 Define CONFIG_PHYSMEM to access this basic support, which
2503 currently only supports clearing the memory.
2508 Define this variable to stop the system in case of a
2509 fatal error, so that you have to reset it manually.
2510 This is probably NOT a good idea for an embedded
2511 system where you want the system to reboot
2512 automatically as fast as possible, but it may be
2513 useful during development since you can try to debug
2514 the conditions that lead to the situation.
2516 CONFIG_NET_RETRY_COUNT
2518 This variable defines the number of retries for
2519 network operations like ARP, RARP, TFTP, or BOOTP
2520 before giving up the operation. If not defined, a
2521 default value of 5 is used.
2525 Timeout waiting for an ARP reply in milliseconds.
2529 Timeout in milliseconds used in NFS protocol.
2530 If you encounter "ERROR: Cannot umount" in nfs command,
2531 try longer timeout such as
2532 #define CONFIG_NFS_TIMEOUT 10000UL
2534 - Command Interpreter:
2535 CONFIG_AUTO_COMPLETE
2537 Enable auto completion of commands using TAB.
2539 CONFIG_SYS_PROMPT_HUSH_PS2
2541 This defines the secondary prompt string, which is
2542 printed when the command interpreter needs more input
2543 to complete a command. Usually "> ".
2547 In the current implementation, the local variables
2548 space and global environment variables space are
2549 separated. Local variables are those you define by
2550 simply typing `name=value'. To access a local
2551 variable later on, you have write `$name' or
2552 `${name}'; to execute the contents of a variable
2553 directly type `$name' at the command prompt.
2555 Global environment variables are those you use
2556 setenv/printenv to work with. To run a command stored
2557 in such a variable, you need to use the run command,
2558 and you must not use the '$' sign to access them.
2560 To store commands and special characters in a
2561 variable, please use double quotation marks
2562 surrounding the whole text of the variable, instead
2563 of the backslashes before semicolons and special
2566 - Command Line Editing and History:
2567 CONFIG_CMDLINE_EDITING
2569 Enable editing and History functions for interactive
2570 command line input operations
2572 - Command Line PS1/PS2 support:
2573 CONFIG_CMDLINE_PS_SUPPORT
2575 Enable support for changing the command prompt string
2576 at run-time. Only static string is supported so far.
2577 The string is obtained from environment variables PS1
2580 - Default Environment:
2581 CONFIG_EXTRA_ENV_SETTINGS
2583 Define this to contain any number of null terminated
2584 strings (variable = value pairs) that will be part of
2585 the default environment compiled into the boot image.
2587 For example, place something like this in your
2588 board's config file:
2590 #define CONFIG_EXTRA_ENV_SETTINGS \
2594 Warning: This method is based on knowledge about the
2595 internal format how the environment is stored by the
2596 U-Boot code. This is NOT an official, exported
2597 interface! Although it is unlikely that this format
2598 will change soon, there is no guarantee either.
2599 You better know what you are doing here.
2601 Note: overly (ab)use of the default environment is
2602 discouraged. Make sure to check other ways to preset
2603 the environment like the "source" command or the
2606 CONFIG_ENV_VARS_UBOOT_CONFIG
2608 Define this in order to add variables describing the
2609 U-Boot build configuration to the default environment.
2610 These will be named arch, cpu, board, vendor, and soc.
2612 Enabling this option will cause the following to be defined:
2620 CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG
2622 Define this in order to add variables describing certain
2623 run-time determined information about the hardware to the
2624 environment. These will be named board_name, board_rev.
2626 CONFIG_DELAY_ENVIRONMENT
2628 Normally the environment is loaded when the board is
2629 initialised so that it is available to U-Boot. This inhibits
2630 that so that the environment is not available until
2631 explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL
2632 this is instead controlled by the value of
2633 /config/load-environment.
2635 - DataFlash Support:
2636 CONFIG_HAS_DATAFLASH
2638 Defining this option enables DataFlash features and
2639 allows to read/write in Dataflash via the standard
2642 - Serial Flash support
2645 Defining this option enables SPI flash commands
2646 'sf probe/read/write/erase/update'.
2648 Usage requires an initial 'probe' to define the serial
2649 flash parameters, followed by read/write/erase/update
2652 The following defaults may be provided by the platform
2653 to handle the common case when only a single serial
2654 flash is present on the system.
2656 CONFIG_SF_DEFAULT_BUS Bus identifier
2657 CONFIG_SF_DEFAULT_CS Chip-select
2658 CONFIG_SF_DEFAULT_MODE (see include/spi.h)
2659 CONFIG_SF_DEFAULT_SPEED in Hz
2663 Define this option to include a destructive SPI flash
2666 CONFIG_SF_DUAL_FLASH Dual flash memories
2668 Define this option to use dual flash support where two flash
2669 memories can be connected with a given cs line.
2670 Currently Xilinx Zynq qspi supports these type of connections.
2672 - SystemACE Support:
2675 Adding this option adds support for Xilinx SystemACE
2676 chips attached via some sort of local bus. The address
2677 of the chip must also be defined in the
2678 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
2680 #define CONFIG_SYSTEMACE
2681 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
2683 When SystemACE support is added, the "ace" device type
2684 becomes available to the fat commands, i.e. fatls.
2686 - TFTP Fixed UDP Port:
2689 If this is defined, the environment variable tftpsrcp
2690 is used to supply the TFTP UDP source port value.
2691 If tftpsrcp isn't defined, the normal pseudo-random port
2692 number generator is used.
2694 Also, the environment variable tftpdstp is used to supply
2695 the TFTP UDP destination port value. If tftpdstp isn't
2696 defined, the normal port 69 is used.
2698 The purpose for tftpsrcp is to allow a TFTP server to
2699 blindly start the TFTP transfer using the pre-configured
2700 target IP address and UDP port. This has the effect of
2701 "punching through" the (Windows XP) firewall, allowing
2702 the remainder of the TFTP transfer to proceed normally.
2703 A better solution is to properly configure the firewall,
2704 but sometimes that is not allowed.
2709 Enable the hash verify command (hash -v). This adds to code
2712 Note: There is also a sha1sum command, which should perhaps
2713 be deprecated in favour of 'hash sha1'.
2715 - bootcount support:
2716 CONFIG_BOOTCOUNT_LIMIT
2718 This enables the bootcounter support, see:
2719 http://www.denx.de/wiki/DULG/UBootBootCountLimit
2722 enable special bootcounter support on at91sam9xe based boards.
2724 enable special bootcounter support on da850 based boards.
2725 CONFIG_BOOTCOUNT_RAM
2726 enable support for the bootcounter in RAM
2727 CONFIG_BOOTCOUNT_I2C
2728 enable support for the bootcounter on an i2c (like RTC) device.
2729 CONFIG_SYS_I2C_RTC_ADDR = i2c chip address
2730 CONFIG_SYS_BOOTCOUNT_ADDR = i2c addr which is used for
2732 CONFIG_BOOTCOUNT_ALEN = address len
2734 - Show boot progress:
2735 CONFIG_SHOW_BOOT_PROGRESS
2737 Defining this option allows to add some board-
2738 specific code (calling a user-provided function
2739 "show_boot_progress(int)") that enables you to show
2740 the system's boot progress on some display (for
2741 example, some LED's) on your board. At the moment,
2742 the following checkpoints are implemented:
2745 Legacy uImage format:
2748 1 common/cmd_bootm.c before attempting to boot an image
2749 -1 common/cmd_bootm.c Image header has bad magic number
2750 2 common/cmd_bootm.c Image header has correct magic number
2751 -2 common/cmd_bootm.c Image header has bad checksum
2752 3 common/cmd_bootm.c Image header has correct checksum
2753 -3 common/cmd_bootm.c Image data has bad checksum
2754 4 common/cmd_bootm.c Image data has correct checksum
2755 -4 common/cmd_bootm.c Image is for unsupported architecture
2756 5 common/cmd_bootm.c Architecture check OK
2757 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
2758 6 common/cmd_bootm.c Image Type check OK
2759 -6 common/cmd_bootm.c gunzip uncompression error
2760 -7 common/cmd_bootm.c Unimplemented compression type
2761 7 common/cmd_bootm.c Uncompression OK
2762 8 common/cmd_bootm.c No uncompress/copy overwrite error
2763 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
2765 9 common/image.c Start initial ramdisk verification
2766 -10 common/image.c Ramdisk header has bad magic number
2767 -11 common/image.c Ramdisk header has bad checksum
2768 10 common/image.c Ramdisk header is OK
2769 -12 common/image.c Ramdisk data has bad checksum
2770 11 common/image.c Ramdisk data has correct checksum
2771 12 common/image.c Ramdisk verification complete, start loading
2772 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
2773 13 common/image.c Start multifile image verification
2774 14 common/image.c No initial ramdisk, no multifile, continue.
2776 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
2778 -30 arch/powerpc/lib/board.c Fatal error, hang the system
2779 -31 post/post.c POST test failed, detected by post_output_backlog()
2780 -32 post/post.c POST test failed, detected by post_run_single()
2782 34 common/cmd_doc.c before loading a Image from a DOC device
2783 -35 common/cmd_doc.c Bad usage of "doc" command
2784 35 common/cmd_doc.c correct usage of "doc" command
2785 -36 common/cmd_doc.c No boot device
2786 36 common/cmd_doc.c correct boot device
2787 -37 common/cmd_doc.c Unknown Chip ID on boot device
2788 37 common/cmd_doc.c correct chip ID found, device available
2789 -38 common/cmd_doc.c Read Error on boot device
2790 38 common/cmd_doc.c reading Image header from DOC device OK
2791 -39 common/cmd_doc.c Image header has bad magic number
2792 39 common/cmd_doc.c Image header has correct magic number
2793 -40 common/cmd_doc.c Error reading Image from DOC device
2794 40 common/cmd_doc.c Image header has correct magic number
2795 41 common/cmd_ide.c before loading a Image from a IDE device
2796 -42 common/cmd_ide.c Bad usage of "ide" command
2797 42 common/cmd_ide.c correct usage of "ide" command
2798 -43 common/cmd_ide.c No boot device
2799 43 common/cmd_ide.c boot device found
2800 -44 common/cmd_ide.c Device not available
2801 44 common/cmd_ide.c Device available
2802 -45 common/cmd_ide.c wrong partition selected
2803 45 common/cmd_ide.c partition selected
2804 -46 common/cmd_ide.c Unknown partition table
2805 46 common/cmd_ide.c valid partition table found
2806 -47 common/cmd_ide.c Invalid partition type
2807 47 common/cmd_ide.c correct partition type
2808 -48 common/cmd_ide.c Error reading Image Header on boot device
2809 48 common/cmd_ide.c reading Image Header from IDE device OK
2810 -49 common/cmd_ide.c Image header has bad magic number
2811 49 common/cmd_ide.c Image header has correct magic number
2812 -50 common/cmd_ide.c Image header has bad checksum
2813 50 common/cmd_ide.c Image header has correct checksum
2814 -51 common/cmd_ide.c Error reading Image from IDE device
2815 51 common/cmd_ide.c reading Image from IDE device OK
2816 52 common/cmd_nand.c before loading a Image from a NAND device
2817 -53 common/cmd_nand.c Bad usage of "nand" command
2818 53 common/cmd_nand.c correct usage of "nand" command
2819 -54 common/cmd_nand.c No boot device
2820 54 common/cmd_nand.c boot device found
2821 -55 common/cmd_nand.c Unknown Chip ID on boot device
2822 55 common/cmd_nand.c correct chip ID found, device available
2823 -56 common/cmd_nand.c Error reading Image Header on boot device
2824 56 common/cmd_nand.c reading Image Header from NAND device OK
2825 -57 common/cmd_nand.c Image header has bad magic number
2826 57 common/cmd_nand.c Image header has correct magic number
2827 -58 common/cmd_nand.c Error reading Image from NAND device
2828 58 common/cmd_nand.c reading Image from NAND device OK
2830 -60 common/env_common.c Environment has a bad CRC, using default
2832 64 net/eth.c starting with Ethernet configuration.
2833 -64 net/eth.c no Ethernet found.
2834 65 net/eth.c Ethernet found.
2836 -80 common/cmd_net.c usage wrong
2837 80 common/cmd_net.c before calling net_loop()
2838 -81 common/cmd_net.c some error in net_loop() occurred
2839 81 common/cmd_net.c net_loop() back without error
2840 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
2841 82 common/cmd_net.c trying automatic boot
2842 83 common/cmd_net.c running "source" command
2843 -83 common/cmd_net.c some error in automatic boot or "source" command
2844 84 common/cmd_net.c end without errors
2849 100 common/cmd_bootm.c Kernel FIT Image has correct format
2850 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
2851 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
2852 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
2853 102 common/cmd_bootm.c Kernel unit name specified
2854 -103 common/cmd_bootm.c Can't get kernel subimage node offset
2855 103 common/cmd_bootm.c Found configuration node
2856 104 common/cmd_bootm.c Got kernel subimage node offset
2857 -104 common/cmd_bootm.c Kernel subimage hash verification failed
2858 105 common/cmd_bootm.c Kernel subimage hash verification OK
2859 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
2860 106 common/cmd_bootm.c Architecture check OK
2861 -106 common/cmd_bootm.c Kernel subimage has wrong type
2862 107 common/cmd_bootm.c Kernel subimage type OK
2863 -107 common/cmd_bootm.c Can't get kernel subimage data/size
2864 108 common/cmd_bootm.c Got kernel subimage data/size
2865 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
2866 -109 common/cmd_bootm.c Can't get kernel subimage type
2867 -110 common/cmd_bootm.c Can't get kernel subimage comp
2868 -111 common/cmd_bootm.c Can't get kernel subimage os
2869 -112 common/cmd_bootm.c Can't get kernel subimage load address
2870 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
2872 120 common/image.c Start initial ramdisk verification
2873 -120 common/image.c Ramdisk FIT image has incorrect format
2874 121 common/image.c Ramdisk FIT image has correct format
2875 122 common/image.c No ramdisk subimage unit name, using configuration
2876 -122 common/image.c Can't get configuration for ramdisk subimage
2877 123 common/image.c Ramdisk unit name specified
2878 -124 common/image.c Can't get ramdisk subimage node offset
2879 125 common/image.c Got ramdisk subimage node offset
2880 -125 common/image.c Ramdisk subimage hash verification failed
2881 126 common/image.c Ramdisk subimage hash verification OK
2882 -126 common/image.c Ramdisk subimage for unsupported architecture
2883 127 common/image.c Architecture check OK
2884 -127 common/image.c Can't get ramdisk subimage data/size
2885 128 common/image.c Got ramdisk subimage data/size
2886 129 common/image.c Can't get ramdisk load address
2887 -129 common/image.c Got ramdisk load address
2889 -130 common/cmd_doc.c Incorrect FIT image format
2890 131 common/cmd_doc.c FIT image format OK
2892 -140 common/cmd_ide.c Incorrect FIT image format
2893 141 common/cmd_ide.c FIT image format OK
2895 -150 common/cmd_nand.c Incorrect FIT image format
2896 151 common/cmd_nand.c FIT image format OK
2898 - legacy image format:
2899 CONFIG_IMAGE_FORMAT_LEGACY
2900 enables the legacy image format support in U-Boot.
2903 enabled if CONFIG_FIT_SIGNATURE is not defined.
2905 CONFIG_DISABLE_IMAGE_LEGACY
2906 disable the legacy image format
2908 This define is introduced, as the legacy image format is
2909 enabled per default for backward compatibility.
2911 - Standalone program support:
2912 CONFIG_STANDALONE_LOAD_ADDR
2914 This option defines a board specific value for the
2915 address where standalone program gets loaded, thus
2916 overwriting the architecture dependent default
2919 - Frame Buffer Address:
2922 Define CONFIG_FB_ADDR if you want to use specific
2923 address for frame buffer. This is typically the case
2924 when using a graphics controller has separate video
2925 memory. U-Boot will then place the frame buffer at
2926 the given address instead of dynamically reserving it
2927 in system RAM by calling lcd_setmem(), which grabs
2928 the memory for the frame buffer depending on the
2929 configured panel size.
2931 Please see board_init_f function.
2933 - Automatic software updates via TFTP server
2935 CONFIG_UPDATE_TFTP_CNT_MAX
2936 CONFIG_UPDATE_TFTP_MSEC_MAX
2938 These options enable and control the auto-update feature;
2939 for a more detailed description refer to doc/README.update.
2941 - MTD Support (mtdparts command, UBI support)
2944 Adds the MTD device infrastructure from the Linux kernel.
2945 Needed for mtdparts command support.
2947 CONFIG_MTD_PARTITIONS
2949 Adds the MTD partitioning infrastructure from the Linux
2950 kernel. Needed for UBI support.
2955 Adds commands for interacting with MTD partitions formatted
2956 with the UBI flash translation layer
2958 Requires also defining CONFIG_RBTREE
2960 CONFIG_UBI_SILENCE_MSG
2962 Make the verbose messages from UBI stop printing. This leaves
2963 warnings and errors enabled.
2966 CONFIG_MTD_UBI_WL_THRESHOLD
2967 This parameter defines the maximum difference between the highest
2968 erase counter value and the lowest erase counter value of eraseblocks
2969 of UBI devices. When this threshold is exceeded, UBI starts performing
2970 wear leveling by means of moving data from eraseblock with low erase
2971 counter to eraseblocks with high erase counter.
2973 The default value should be OK for SLC NAND flashes, NOR flashes and
2974 other flashes which have eraseblock life-cycle 100000 or more.
2975 However, in case of MLC NAND flashes which typically have eraseblock
2976 life-cycle less than 10000, the threshold should be lessened (e.g.,
2977 to 128 or 256, although it does not have to be power of 2).
2981 CONFIG_MTD_UBI_BEB_LIMIT
2982 This option specifies the maximum bad physical eraseblocks UBI
2983 expects on the MTD device (per 1024 eraseblocks). If the
2984 underlying flash does not admit of bad eraseblocks (e.g. NOR
2985 flash), this value is ignored.
2987 NAND datasheets often specify the minimum and maximum NVM
2988 (Number of Valid Blocks) for the flashes' endurance lifetime.
2989 The maximum expected bad eraseblocks per 1024 eraseblocks
2990 then can be calculated as "1024 * (1 - MinNVB / MaxNVB)",
2991 which gives 20 for most NANDs (MaxNVB is basically the total
2992 count of eraseblocks on the chip).
2994 To put it differently, if this value is 20, UBI will try to
2995 reserve about 1.9% of physical eraseblocks for bad blocks
2996 handling. And that will be 1.9% of eraseblocks on the entire
2997 NAND chip, not just the MTD partition UBI attaches. This means
2998 that if you have, say, a NAND flash chip admits maximum 40 bad
2999 eraseblocks, and it is split on two MTD partitions of the same
3000 size, UBI will reserve 40 eraseblocks when attaching a
3005 CONFIG_MTD_UBI_FASTMAP
3006 Fastmap is a mechanism which allows attaching an UBI device
3007 in nearly constant time. Instead of scanning the whole MTD device it
3008 only has to locate a checkpoint (called fastmap) on the device.
3009 The on-flash fastmap contains all information needed to attach
3010 the device. Using fastmap makes only sense on large devices where
3011 attaching by scanning takes long. UBI will not automatically install
3012 a fastmap on old images, but you can set the UBI parameter
3013 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT to 1 if you want so. Please note
3014 that fastmap-enabled images are still usable with UBI implementations
3015 without fastmap support. On typical flash devices the whole fastmap
3016 fits into one PEB. UBI will reserve PEBs to hold two fastmaps.
3018 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT
3019 Set this parameter to enable fastmap automatically on images
3023 CONFIG_MTD_UBI_FM_DEBUG
3024 Enable UBI fastmap debug
3030 Adds commands for interacting with UBI volumes formatted as
3031 UBIFS. UBIFS is read-only in u-boot.
3033 Requires UBI support as well as CONFIG_LZO
3035 CONFIG_UBIFS_SILENCE_MSG
3037 Make the verbose messages from UBIFS stop printing. This leaves
3038 warnings and errors enabled.
3042 Enable building of SPL globally.
3045 LDSCRIPT for linking the SPL binary.
3047 CONFIG_SPL_MAX_FOOTPRINT
3048 Maximum size in memory allocated to the SPL, BSS included.
3049 When defined, the linker checks that the actual memory
3050 used by SPL from _start to __bss_end does not exceed it.
3051 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3052 must not be both defined at the same time.
3055 Maximum size of the SPL image (text, data, rodata, and
3056 linker lists sections), BSS excluded.
3057 When defined, the linker checks that the actual size does
3060 CONFIG_SPL_TEXT_BASE
3061 TEXT_BASE for linking the SPL binary.
3063 CONFIG_SPL_RELOC_TEXT_BASE
3064 Address to relocate to. If unspecified, this is equal to
3065 CONFIG_SPL_TEXT_BASE (i.e. no relocation is done).
3067 CONFIG_SPL_BSS_START_ADDR
3068 Link address for the BSS within the SPL binary.
3070 CONFIG_SPL_BSS_MAX_SIZE
3071 Maximum size in memory allocated to the SPL BSS.
3072 When defined, the linker checks that the actual memory used
3073 by SPL from __bss_start to __bss_end does not exceed it.
3074 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3075 must not be both defined at the same time.
3078 Adress of the start of the stack SPL will use
3080 CONFIG_SPL_PANIC_ON_RAW_IMAGE
3081 When defined, SPL will panic() if the image it has
3082 loaded does not have a signature.
3083 Defining this is useful when code which loads images
3084 in SPL cannot guarantee that absolutely all read errors
3086 An example is the LPC32XX MLC NAND driver, which will
3087 consider that a completely unreadable NAND block is bad,
3088 and thus should be skipped silently.
3090 CONFIG_SPL_RELOC_STACK
3091 Adress of the start of the stack SPL will use after
3092 relocation. If unspecified, this is equal to
3095 CONFIG_SYS_SPL_MALLOC_START
3096 Starting address of the malloc pool used in SPL.
3097 When this option is set the full malloc is used in SPL and
3098 it is set up by spl_init() and before that, the simple malloc()
3099 can be used if CONFIG_SYS_MALLOC_F is defined.
3101 CONFIG_SYS_SPL_MALLOC_SIZE
3102 The size of the malloc pool used in SPL.
3104 CONFIG_SPL_FRAMEWORK
3105 Enable the SPL framework under common/. This framework
3106 supports MMC, NAND and YMODEM loading of U-Boot and NAND
3107 NAND loading of the Linux Kernel.
3110 Enable booting directly to an OS from SPL.
3111 See also: doc/README.falcon
3113 CONFIG_SPL_DISPLAY_PRINT
3114 For ARM, enable an optional function to print more information
3115 about the running system.
3117 CONFIG_SPL_INIT_MINIMAL
3118 Arch init code should be built for a very small image
3120 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_PARTITION
3121 Partition on the MMC to load U-Boot from when the MMC is being
3124 CONFIG_SYS_MMCSD_RAW_MODE_KERNEL_SECTOR
3125 Sector to load kernel uImage from when MMC is being
3126 used in raw mode (for Falcon mode)
3128 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTOR,
3129 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTORS
3130 Sector and number of sectors to load kernel argument
3131 parameters from when MMC is being used in raw mode
3134 CONFIG_SYS_MMCSD_FS_BOOT_PARTITION
3135 Partition on the MMC to load U-Boot from when the MMC is being
3138 CONFIG_SPL_FS_LOAD_PAYLOAD_NAME
3139 Filename to read to load U-Boot when reading from filesystem
3141 CONFIG_SPL_FS_LOAD_KERNEL_NAME
3142 Filename to read to load kernel uImage when reading
3143 from filesystem (for Falcon mode)
3145 CONFIG_SPL_FS_LOAD_ARGS_NAME
3146 Filename to read to load kernel argument parameters
3147 when reading from filesystem (for Falcon mode)
3149 CONFIG_SPL_MPC83XX_WAIT_FOR_NAND
3150 Set this for NAND SPL on PPC mpc83xx targets, so that
3151 start.S waits for the rest of the SPL to load before
3152 continuing (the hardware starts execution after just
3153 loading the first page rather than the full 4K).
3155 CONFIG_SPL_SKIP_RELOCATE
3156 Avoid SPL relocation
3158 CONFIG_SPL_NAND_BASE
3159 Include nand_base.c in the SPL. Requires
3160 CONFIG_SPL_NAND_DRIVERS.
3162 CONFIG_SPL_NAND_DRIVERS
3163 SPL uses normal NAND drivers, not minimal drivers.
3166 Include standard software ECC in the SPL
3168 CONFIG_SPL_NAND_SIMPLE
3169 Support for NAND boot using simple NAND drivers that
3170 expose the cmd_ctrl() interface.
3173 Support for a lightweight UBI (fastmap) scanner and
3176 CONFIG_SPL_NAND_RAW_ONLY
3177 Support to boot only raw u-boot.bin images. Use this only
3178 if you need to save space.
3180 CONFIG_SPL_COMMON_INIT_DDR
3181 Set for common ddr init with serial presence detect in
3184 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
3185 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
3186 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
3187 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
3188 CONFIG_SYS_NAND_ECCBYTES
3189 Defines the size and behavior of the NAND that SPL uses
3192 CONFIG_SPL_NAND_BOOT
3193 Add support NAND boot
3195 CONFIG_SYS_NAND_U_BOOT_OFFS
3196 Location in NAND to read U-Boot from
3198 CONFIG_SYS_NAND_U_BOOT_DST
3199 Location in memory to load U-Boot to
3201 CONFIG_SYS_NAND_U_BOOT_SIZE
3202 Size of image to load
3204 CONFIG_SYS_NAND_U_BOOT_START
3205 Entry point in loaded image to jump to
3207 CONFIG_SYS_NAND_HW_ECC_OOBFIRST
3208 Define this if you need to first read the OOB and then the
3209 data. This is used, for example, on davinci platforms.
3211 CONFIG_SPL_OMAP3_ID_NAND
3212 Support for an OMAP3-specific set of functions to return the
3213 ID and MFR of the first attached NAND chip, if present.
3215 CONFIG_SPL_RAM_DEVICE
3216 Support for running image already present in ram, in SPL binary
3219 Image offset to which the SPL should be padded before appending
3220 the SPL payload. By default, this is defined as
3221 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3222 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3223 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3226 Final target image containing SPL and payload. Some SPLs
3227 use an arch-specific makefile fragment instead, for
3228 example if more than one image needs to be produced.
3230 CONFIG_FIT_SPL_PRINT
3231 Printing information about a FIT image adds quite a bit of
3232 code to SPL. So this is normally disabled in SPL. Use this
3233 option to re-enable it. This will affect the output of the
3234 bootm command when booting a FIT image.
3238 Enable building of TPL globally.
3241 Image offset to which the TPL should be padded before appending
3242 the TPL payload. By default, this is defined as
3243 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3244 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3245 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3247 - Interrupt support (PPC):
3249 There are common interrupt_init() and timer_interrupt()
3250 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
3251 for CPU specific initialization. interrupt_init_cpu()
3252 should set decrementer_count to appropriate value. If
3253 CPU resets decrementer automatically after interrupt
3254 (ppc4xx) it should set decrementer_count to zero.
3255 timer_interrupt() calls timer_interrupt_cpu() for CPU
3256 specific handling. If board has watchdog / status_led
3257 / other_activity_monitor it works automatically from
3258 general timer_interrupt().
3261 Board initialization settings:
3262 ------------------------------
3264 During Initialization u-boot calls a number of board specific functions
3265 to allow the preparation of board specific prerequisites, e.g. pin setup
3266 before drivers are initialized. To enable these callbacks the
3267 following configuration macros have to be defined. Currently this is
3268 architecture specific, so please check arch/your_architecture/lib/board.c
3269 typically in board_init_f() and board_init_r().
3271 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
3272 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
3273 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
3274 - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
3276 Configuration Settings:
3277 -----------------------
3279 - CONFIG_SYS_SUPPORT_64BIT_DATA: Defined automatically if compiled as 64-bit.
3280 Optionally it can be defined to support 64-bit memory commands.
3282 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
3283 undefine this when you're short of memory.
3285 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
3286 width of the commands listed in the 'help' command output.
3288 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
3289 prompt for user input.
3291 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
3293 - CONFIG_SYS_PBSIZE: Buffer size for Console output
3295 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
3297 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
3298 the application (usually a Linux kernel) when it is
3301 - CONFIG_SYS_BAUDRATE_TABLE:
3302 List of legal baudrate settings for this board.
3304 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
3305 Begin and End addresses of the area used by the
3308 - CONFIG_SYS_ALT_MEMTEST:
3309 Enable an alternate, more extensive memory test.
3311 - CONFIG_SYS_MEMTEST_SCRATCH:
3312 Scratch address used by the alternate memory test
3313 You only need to set this if address zero isn't writeable
3315 - CONFIG_SYS_MEM_RESERVE_SECURE
3316 Only implemented for ARMv8 for now.
3317 If defined, the size of CONFIG_SYS_MEM_RESERVE_SECURE memory
3318 is substracted from total RAM and won't be reported to OS.
3319 This memory can be used as secure memory. A variable
3320 gd->arch.secure_ram is used to track the location. In systems
3321 the RAM base is not zero, or RAM is divided into banks,
3322 this variable needs to be recalcuated to get the address.
3324 - CONFIG_SYS_MEM_TOP_HIDE:
3325 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
3326 this specified memory area will get subtracted from the top
3327 (end) of RAM and won't get "touched" at all by U-Boot. By
3328 fixing up gd->ram_size the Linux kernel should gets passed
3329 the now "corrected" memory size and won't touch it either.
3330 This should work for arch/ppc and arch/powerpc. Only Linux
3331 board ports in arch/powerpc with bootwrapper support that
3332 recalculate the memory size from the SDRAM controller setup
3333 will have to get fixed in Linux additionally.
3335 This option can be used as a workaround for the 440EPx/GRx
3336 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
3339 WARNING: Please make sure that this value is a multiple of
3340 the Linux page size (normally 4k). If this is not the case,
3341 then the end address of the Linux memory will be located at a
3342 non page size aligned address and this could cause major
3345 - CONFIG_SYS_LOADS_BAUD_CHANGE:
3346 Enable temporary baudrate change while serial download
3348 - CONFIG_SYS_SDRAM_BASE:
3349 Physical start address of SDRAM. _Must_ be 0 here.
3351 - CONFIG_SYS_FLASH_BASE:
3352 Physical start address of Flash memory.
3354 - CONFIG_SYS_MONITOR_BASE:
3355 Physical start address of boot monitor code (set by
3356 make config files to be same as the text base address
3357 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
3358 CONFIG_SYS_FLASH_BASE when booting from flash.
3360 - CONFIG_SYS_MONITOR_LEN:
3361 Size of memory reserved for monitor code, used to
3362 determine _at_compile_time_ (!) if the environment is
3363 embedded within the U-Boot image, or in a separate
3366 - CONFIG_SYS_MALLOC_LEN:
3367 Size of DRAM reserved for malloc() use.
3369 - CONFIG_SYS_MALLOC_F_LEN
3370 Size of the malloc() pool for use before relocation. If
3371 this is defined, then a very simple malloc() implementation
3372 will become available before relocation. The address is just
3373 below the global data, and the stack is moved down to make
3376 This feature allocates regions with increasing addresses
3377 within the region. calloc() is supported, but realloc()
3378 is not available. free() is supported but does nothing.
3379 The memory will be freed (or in fact just forgotten) when
3380 U-Boot relocates itself.
3382 - CONFIG_SYS_MALLOC_SIMPLE
3383 Provides a simple and small malloc() and calloc() for those
3384 boards which do not use the full malloc in SPL (which is
3385 enabled with CONFIG_SYS_SPL_MALLOC_START).
3387 - CONFIG_SYS_NONCACHED_MEMORY:
3388 Size of non-cached memory area. This area of memory will be
3389 typically located right below the malloc() area and mapped
3390 uncached in the MMU. This is useful for drivers that would
3391 otherwise require a lot of explicit cache maintenance. For
3392 some drivers it's also impossible to properly maintain the
3393 cache. For example if the regions that need to be flushed
3394 are not a multiple of the cache-line size, *and* padding
3395 cannot be allocated between the regions to align them (i.e.
3396 if the HW requires a contiguous array of regions, and the
3397 size of each region is not cache-aligned), then a flush of
3398 one region may result in overwriting data that hardware has
3399 written to another region in the same cache-line. This can
3400 happen for example in network drivers where descriptors for
3401 buffers are typically smaller than the CPU cache-line (e.g.
3402 16 bytes vs. 32 or 64 bytes).
3404 Non-cached memory is only supported on 32-bit ARM at present.
3406 - CONFIG_SYS_BOOTM_LEN:
3407 Normally compressed uImages are limited to an
3408 uncompressed size of 8 MBytes. If this is not enough,
3409 you can define CONFIG_SYS_BOOTM_LEN in your board config file
3410 to adjust this setting to your needs.
3412 - CONFIG_SYS_BOOTMAPSZ:
3413 Maximum size of memory mapped by the startup code of
3414 the Linux kernel; all data that must be processed by
3415 the Linux kernel (bd_info, boot arguments, FDT blob if
3416 used) must be put below this limit, unless "bootm_low"
3417 environment variable is defined and non-zero. In such case
3418 all data for the Linux kernel must be between "bootm_low"
3419 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
3420 variable "bootm_mapsize" will override the value of
3421 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
3422 then the value in "bootm_size" will be used instead.
3424 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
3425 Enable initrd_high functionality. If defined then the
3426 initrd_high feature is enabled and the bootm ramdisk subcommand
3429 - CONFIG_SYS_BOOT_GET_CMDLINE:
3430 Enables allocating and saving kernel cmdline in space between
3431 "bootm_low" and "bootm_low" + BOOTMAPSZ.
3433 - CONFIG_SYS_BOOT_GET_KBD:
3434 Enables allocating and saving a kernel copy of the bd_info in
3435 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
3437 - CONFIG_SYS_MAX_FLASH_BANKS:
3438 Max number of Flash memory banks
3440 - CONFIG_SYS_MAX_FLASH_SECT:
3441 Max number of sectors on a Flash chip
3443 - CONFIG_SYS_FLASH_ERASE_TOUT:
3444 Timeout for Flash erase operations (in ms)
3446 - CONFIG_SYS_FLASH_WRITE_TOUT:
3447 Timeout for Flash write operations (in ms)
3449 - CONFIG_SYS_FLASH_LOCK_TOUT
3450 Timeout for Flash set sector lock bit operation (in ms)
3452 - CONFIG_SYS_FLASH_UNLOCK_TOUT
3453 Timeout for Flash clear lock bits operation (in ms)
3455 - CONFIG_SYS_FLASH_PROTECTION
3456 If defined, hardware flash sectors protection is used
3457 instead of U-Boot software protection.
3459 - CONFIG_SYS_DIRECT_FLASH_TFTP:
3461 Enable TFTP transfers directly to flash memory;
3462 without this option such a download has to be
3463 performed in two steps: (1) download to RAM, and (2)
3464 copy from RAM to flash.
3466 The two-step approach is usually more reliable, since
3467 you can check if the download worked before you erase
3468 the flash, but in some situations (when system RAM is
3469 too limited to allow for a temporary copy of the
3470 downloaded image) this option may be very useful.
3472 - CONFIG_SYS_FLASH_CFI:
3473 Define if the flash driver uses extra elements in the
3474 common flash structure for storing flash geometry.
3476 - CONFIG_FLASH_CFI_DRIVER
3477 This option also enables the building of the cfi_flash driver
3478 in the drivers directory
3480 - CONFIG_FLASH_CFI_MTD
3481 This option enables the building of the cfi_mtd driver
3482 in the drivers directory. The driver exports CFI flash
3485 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
3486 Use buffered writes to flash.
3488 - CONFIG_FLASH_SPANSION_S29WS_N
3489 s29ws-n MirrorBit flash has non-standard addresses for buffered
3492 - CONFIG_SYS_FLASH_QUIET_TEST
3493 If this option is defined, the common CFI flash doesn't
3494 print it's warning upon not recognized FLASH banks. This
3495 is useful, if some of the configured banks are only
3496 optionally available.
3498 - CONFIG_FLASH_SHOW_PROGRESS
3499 If defined (must be an integer), print out countdown
3500 digits and dots. Recommended value: 45 (9..1) for 80
3501 column displays, 15 (3..1) for 40 column displays.
3503 - CONFIG_FLASH_VERIFY
3504 If defined, the content of the flash (destination) is compared
3505 against the source after the write operation. An error message
3506 will be printed when the contents are not identical.
3507 Please note that this option is useless in nearly all cases,
3508 since such flash programming errors usually are detected earlier
3509 while unprotecting/erasing/programming. Please only enable
3510 this option if you really know what you are doing.
3512 - CONFIG_SYS_RX_ETH_BUFFER:
3513 Defines the number of Ethernet receive buffers. On some
3514 Ethernet controllers it is recommended to set this value
3515 to 8 or even higher (EEPRO100 or 405 EMAC), since all
3516 buffers can be full shortly after enabling the interface
3517 on high Ethernet traffic.
3518 Defaults to 4 if not defined.
3520 - CONFIG_ENV_MAX_ENTRIES
3522 Maximum number of entries in the hash table that is used
3523 internally to store the environment settings. The default
3524 setting is supposed to be generous and should work in most
3525 cases. This setting can be used to tune behaviour; see
3526 lib/hashtable.c for details.
3528 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3529 - CONFIG_ENV_FLAGS_LIST_STATIC
3530 Enable validation of the values given to environment variables when
3531 calling env set. Variables can be restricted to only decimal,
3532 hexadecimal, or boolean. If CONFIG_CMD_NET is also defined,
3533 the variables can also be restricted to IP address or MAC address.
3535 The format of the list is:
3536 type_attribute = [s|d|x|b|i|m]
3537 access_attribute = [a|r|o|c]
3538 attributes = type_attribute[access_attribute]
3539 entry = variable_name[:attributes]
3542 The type attributes are:
3543 s - String (default)
3546 b - Boolean ([1yYtT|0nNfF])
3550 The access attributes are:
3556 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3557 Define this to a list (string) to define the ".flags"
3558 environment variable in the default or embedded environment.
3560 - CONFIG_ENV_FLAGS_LIST_STATIC
3561 Define this to a list (string) to define validation that
3562 should be done if an entry is not found in the ".flags"
3563 environment variable. To override a setting in the static
3564 list, simply add an entry for the same variable name to the
3567 If CONFIG_REGEX is defined, the variable_name above is evaluated as a
3568 regular expression. This allows multiple variables to define the same
3569 flags without explicitly listing them for each variable.
3571 - CONFIG_ENV_ACCESS_IGNORE_FORCE
3572 If defined, don't allow the -f switch to env set override variable
3576 If stdint.h is available with your toolchain you can define this
3577 option to enable it. You can provide option 'USE_STDINT=1' when
3578 building U-Boot to enable this.
3580 The following definitions that deal with the placement and management
3581 of environment data (variable area); in general, we support the
3582 following configurations:
3584 - CONFIG_BUILD_ENVCRC:
3586 Builds up envcrc with the target environment so that external utils
3587 may easily extract it and embed it in final U-Boot images.
3589 - CONFIG_ENV_IS_IN_FLASH:
3591 Define this if the environment is in flash memory.
3593 a) The environment occupies one whole flash sector, which is
3594 "embedded" in the text segment with the U-Boot code. This
3595 happens usually with "bottom boot sector" or "top boot
3596 sector" type flash chips, which have several smaller
3597 sectors at the start or the end. For instance, such a
3598 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
3599 such a case you would place the environment in one of the
3600 4 kB sectors - with U-Boot code before and after it. With
3601 "top boot sector" type flash chips, you would put the
3602 environment in one of the last sectors, leaving a gap
3603 between U-Boot and the environment.
3605 - CONFIG_ENV_OFFSET:
3607 Offset of environment data (variable area) to the
3608 beginning of flash memory; for instance, with bottom boot
3609 type flash chips the second sector can be used: the offset
3610 for this sector is given here.
3612 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
3616 This is just another way to specify the start address of
3617 the flash sector containing the environment (instead of
3620 - CONFIG_ENV_SECT_SIZE:
3622 Size of the sector containing the environment.
3625 b) Sometimes flash chips have few, equal sized, BIG sectors.
3626 In such a case you don't want to spend a whole sector for
3631 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
3632 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
3633 of this flash sector for the environment. This saves
3634 memory for the RAM copy of the environment.
3636 It may also save flash memory if you decide to use this
3637 when your environment is "embedded" within U-Boot code,
3638 since then the remainder of the flash sector could be used
3639 for U-Boot code. It should be pointed out that this is
3640 STRONGLY DISCOURAGED from a robustness point of view:
3641 updating the environment in flash makes it always
3642 necessary to erase the WHOLE sector. If something goes
3643 wrong before the contents has been restored from a copy in
3644 RAM, your target system will be dead.
3646 - CONFIG_ENV_ADDR_REDUND
3647 CONFIG_ENV_SIZE_REDUND
3649 These settings describe a second storage area used to hold
3650 a redundant copy of the environment data, so that there is
3651 a valid backup copy in case there is a power failure during
3652 a "saveenv" operation.
3654 BE CAREFUL! Any changes to the flash layout, and some changes to the
3655 source code will make it necessary to adapt <board>/u-boot.lds*
3659 - CONFIG_ENV_IS_IN_NVRAM:
3661 Define this if you have some non-volatile memory device
3662 (NVRAM, battery buffered SRAM) which you want to use for the
3668 These two #defines are used to determine the memory area you
3669 want to use for environment. It is assumed that this memory
3670 can just be read and written to, without any special
3673 BE CAREFUL! The first access to the environment happens quite early
3674 in U-Boot initialization (when we try to get the setting of for the
3675 console baudrate). You *MUST* have mapped your NVRAM area then, or
3678 Please note that even with NVRAM we still use a copy of the
3679 environment in RAM: we could work on NVRAM directly, but we want to
3680 keep settings there always unmodified except somebody uses "saveenv"
3681 to save the current settings.
3684 - CONFIG_ENV_IS_IN_EEPROM:
3686 Use this if you have an EEPROM or similar serial access
3687 device and a driver for it.
3689 - CONFIG_ENV_OFFSET:
3692 These two #defines specify the offset and size of the
3693 environment area within the total memory of your EEPROM.
3695 - CONFIG_SYS_I2C_EEPROM_ADDR:
3696 If defined, specified the chip address of the EEPROM device.
3697 The default address is zero.
3699 - CONFIG_SYS_I2C_EEPROM_BUS:
3700 If defined, specified the i2c bus of the EEPROM device.
3702 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
3703 If defined, the number of bits used to address bytes in a
3704 single page in the EEPROM device. A 64 byte page, for example
3705 would require six bits.
3707 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
3708 If defined, the number of milliseconds to delay between
3709 page writes. The default is zero milliseconds.
3711 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
3712 The length in bytes of the EEPROM memory array address. Note
3713 that this is NOT the chip address length!
3715 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
3716 EEPROM chips that implement "address overflow" are ones
3717 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
3718 address and the extra bits end up in the "chip address" bit
3719 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
3722 Note that we consider the length of the address field to
3723 still be one byte because the extra address bits are hidden
3724 in the chip address.
3726 - CONFIG_SYS_EEPROM_SIZE:
3727 The size in bytes of the EEPROM device.
3729 - CONFIG_ENV_EEPROM_IS_ON_I2C
3730 define this, if you have I2C and SPI activated, and your
3731 EEPROM, which holds the environment, is on the I2C bus.
3733 - CONFIG_I2C_ENV_EEPROM_BUS
3734 if you have an Environment on an EEPROM reached over
3735 I2C muxes, you can define here, how to reach this
3736 EEPROM. For example:
3738 #define CONFIG_I2C_ENV_EEPROM_BUS 1
3740 EEPROM which holds the environment, is reached over
3741 a pca9547 i2c mux with address 0x70, channel 3.
3743 - CONFIG_ENV_IS_IN_DATAFLASH:
3745 Define this if you have a DataFlash memory device which you
3746 want to use for the environment.
3748 - CONFIG_ENV_OFFSET:
3752 These three #defines specify the offset and size of the
3753 environment area within the total memory of your DataFlash placed
3754 at the specified address.
3756 - CONFIG_ENV_IS_IN_SPI_FLASH:
3758 Define this if you have a SPI Flash memory device which you
3759 want to use for the environment.
3761 - CONFIG_ENV_OFFSET:
3764 These two #defines specify the offset and size of the
3765 environment area within the SPI Flash. CONFIG_ENV_OFFSET must be
3766 aligned to an erase sector boundary.
3768 - CONFIG_ENV_SECT_SIZE:
3770 Define the SPI flash's sector size.
3772 - CONFIG_ENV_OFFSET_REDUND (optional):
3774 This setting describes a second storage area of CONFIG_ENV_SIZE
3775 size used to hold a redundant copy of the environment data, so
3776 that there is a valid backup copy in case there is a power failure
3777 during a "saveenv" operation. CONFIG_ENV_OFFSET_REDUND must be
3778 aligned to an erase sector boundary.
3780 - CONFIG_ENV_SPI_BUS (optional):
3781 - CONFIG_ENV_SPI_CS (optional):
3783 Define the SPI bus and chip select. If not defined they will be 0.
3785 - CONFIG_ENV_SPI_MAX_HZ (optional):
3787 Define the SPI max work clock. If not defined then use 1MHz.
3789 - CONFIG_ENV_SPI_MODE (optional):
3791 Define the SPI work mode. If not defined then use SPI_MODE_3.
3793 - CONFIG_ENV_IS_IN_REMOTE:
3795 Define this if you have a remote memory space which you
3796 want to use for the local device's environment.
3801 These two #defines specify the address and size of the
3802 environment area within the remote memory space. The
3803 local device can get the environment from remote memory
3804 space by SRIO or PCIE links.
3806 BE CAREFUL! For some special cases, the local device can not use
3807 "saveenv" command. For example, the local device will get the
3808 environment stored in a remote NOR flash by SRIO or PCIE link,
3809 but it can not erase, write this NOR flash by SRIO or PCIE interface.
3811 - CONFIG_ENV_IS_IN_NAND:
3813 Define this if you have a NAND device which you want to use
3814 for the environment.
3816 - CONFIG_ENV_OFFSET:
3819 These two #defines specify the offset and size of the environment
3820 area within the first NAND device. CONFIG_ENV_OFFSET must be
3821 aligned to an erase block boundary.
3823 - CONFIG_ENV_OFFSET_REDUND (optional):
3825 This setting describes a second storage area of CONFIG_ENV_SIZE
3826 size used to hold a redundant copy of the environment data, so
3827 that there is a valid backup copy in case there is a power failure
3828 during a "saveenv" operation. CONFIG_ENV_OFFSET_REDUND must be
3829 aligned to an erase block boundary.
3831 - CONFIG_ENV_RANGE (optional):
3833 Specifies the length of the region in which the environment
3834 can be written. This should be a multiple of the NAND device's
3835 block size. Specifying a range with more erase blocks than
3836 are needed to hold CONFIG_ENV_SIZE allows bad blocks within
3837 the range to be avoided.
3839 - CONFIG_ENV_OFFSET_OOB (optional):
3841 Enables support for dynamically retrieving the offset of the
3842 environment from block zero's out-of-band data. The
3843 "nand env.oob" command can be used to record this offset.
3844 Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
3845 using CONFIG_ENV_OFFSET_OOB.
3847 - CONFIG_NAND_ENV_DST
3849 Defines address in RAM to which the nand_spl code should copy the
3850 environment. If redundant environment is used, it will be copied to
3851 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
3853 - CONFIG_ENV_IS_IN_UBI:
3855 Define this if you have an UBI volume that you want to use for the
3856 environment. This has the benefit of wear-leveling the environment
3857 accesses, which is important on NAND.
3859 - CONFIG_ENV_UBI_PART:
3861 Define this to a string that is the mtd partition containing the UBI.
3863 - CONFIG_ENV_UBI_VOLUME:
3865 Define this to the name of the volume that you want to store the
3868 - CONFIG_ENV_UBI_VOLUME_REDUND:
3870 Define this to the name of another volume to store a second copy of
3871 the environment in. This will enable redundant environments in UBI.
3872 It is assumed that both volumes are in the same MTD partition.
3874 - CONFIG_UBI_SILENCE_MSG
3875 - CONFIG_UBIFS_SILENCE_MSG
3877 You will probably want to define these to avoid a really noisy system
3878 when storing the env in UBI.
3880 - CONFIG_ENV_IS_IN_FAT:
3881 Define this if you want to use the FAT file system for the environment.
3883 - FAT_ENV_INTERFACE:
3885 Define this to a string that is the name of the block device.
3887 - FAT_ENV_DEVICE_AND_PART:
3889 Define this to a string to specify the partition of the device. It can
3892 "D:P", "D:0", "D", "D:" or "D:auto" (D, P are integers. And P >= 1)
3893 - "D:P": device D partition P. Error occurs if device D has no
3896 - "D" or "D:": device D partition 1 if device D has partition
3897 table, or the whole device D if has no partition
3899 - "D:auto": first partition in device D with bootable flag set.
3900 If none, first valid partition in device D. If no
3901 partition table then means device D.
3905 It's a string of the FAT file name. This file use to store the
3909 This should be defined. Otherwise it cannot save the environment file.
3911 - CONFIG_ENV_IS_IN_MMC:
3913 Define this if you have an MMC device which you want to use for the
3916 - CONFIG_SYS_MMC_ENV_DEV:
3918 Specifies which MMC device the environment is stored in.
3920 - CONFIG_SYS_MMC_ENV_PART (optional):
3922 Specifies which MMC partition the environment is stored in. If not
3923 set, defaults to partition 0, the user area. Common values might be
3924 1 (first MMC boot partition), 2 (second MMC boot partition).
3926 - CONFIG_ENV_OFFSET:
3929 These two #defines specify the offset and size of the environment
3930 area within the specified MMC device.
3932 If offset is positive (the usual case), it is treated as relative to
3933 the start of the MMC partition. If offset is negative, it is treated
3934 as relative to the end of the MMC partition. This can be useful if
3935 your board may be fitted with different MMC devices, which have
3936 different sizes for the MMC partitions, and you always want the
3937 environment placed at the very end of the partition, to leave the
3938 maximum possible space before it, to store other data.
3940 These two values are in units of bytes, but must be aligned to an
3941 MMC sector boundary.
3943 - CONFIG_ENV_OFFSET_REDUND (optional):
3945 Specifies a second storage area, of CONFIG_ENV_SIZE size, used to
3946 hold a redundant copy of the environment data. This provides a
3947 valid backup copy in case the other copy is corrupted, e.g. due
3948 to a power failure during a "saveenv" operation.
3950 This value may also be positive or negative; this is handled in the
3951 same way as CONFIG_ENV_OFFSET.
3953 This value is also in units of bytes, but must also be aligned to
3954 an MMC sector boundary.
3956 - CONFIG_ENV_SIZE_REDUND (optional):
3958 This value need not be set, even when CONFIG_ENV_OFFSET_REDUND is
3959 set. If this value is set, it must be set to the same value as
3962 - CONFIG_SYS_SPI_INIT_OFFSET
3964 Defines offset to the initial SPI buffer area in DPRAM. The
3965 area is used at an early stage (ROM part) if the environment
3966 is configured to reside in the SPI EEPROM: We need a 520 byte
3967 scratch DPRAM area. It is used between the two initialization
3968 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
3969 to be a good choice since it makes it far enough from the
3970 start of the data area as well as from the stack pointer.
3972 Please note that the environment is read-only until the monitor
3973 has been relocated to RAM and a RAM copy of the environment has been
3974 created; also, when using EEPROM you will have to use getenv_f()
3975 until then to read environment variables.
3977 The environment is protected by a CRC32 checksum. Before the monitor
3978 is relocated into RAM, as a result of a bad CRC you will be working
3979 with the compiled-in default environment - *silently*!!! [This is
3980 necessary, because the first environment variable we need is the
3981 "baudrate" setting for the console - if we have a bad CRC, we don't
3982 have any device yet where we could complain.]
3984 Note: once the monitor has been relocated, then it will complain if
3985 the default environment is used; a new CRC is computed as soon as you
3986 use the "saveenv" command to store a valid environment.
3988 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
3989 Echo the inverted Ethernet link state to the fault LED.
3991 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
3992 also needs to be defined.
3994 - CONFIG_SYS_FAULT_MII_ADDR:
3995 MII address of the PHY to check for the Ethernet link state.
3997 - CONFIG_NS16550_MIN_FUNCTIONS:
3998 Define this if you desire to only have use of the NS16550_init
3999 and NS16550_putc functions for the serial driver located at
4000 drivers/serial/ns16550.c. This option is useful for saving
4001 space for already greatly restricted images, including but not
4002 limited to NAND_SPL configurations.
4004 - CONFIG_DISPLAY_BOARDINFO
4005 Display information about the board that U-Boot is running on
4006 when U-Boot starts up. The board function checkboard() is called
4009 - CONFIG_DISPLAY_BOARDINFO_LATE
4010 Similar to the previous option, but display this information
4011 later, once stdio is running and output goes to the LCD, if
4014 - CONFIG_BOARD_SIZE_LIMIT:
4015 Maximum size of the U-Boot image. When defined, the
4016 build system checks that the actual size does not
4019 Low Level (hardware related) configuration options:
4020 ---------------------------------------------------
4022 - CONFIG_SYS_CACHELINE_SIZE:
4023 Cache Line Size of the CPU.
4025 - CONFIG_SYS_DEFAULT_IMMR:
4026 Default address of the IMMR after system reset.
4028 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
4029 and RPXsuper) to be able to adjust the position of
4030 the IMMR register after a reset.
4032 - CONFIG_SYS_CCSRBAR_DEFAULT:
4033 Default (power-on reset) physical address of CCSR on Freescale
4036 - CONFIG_SYS_CCSRBAR:
4037 Virtual address of CCSR. On a 32-bit build, this is typically
4038 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
4040 CONFIG_SYS_DEFAULT_IMMR must also be set to this value,
4041 for cross-platform code that uses that macro instead.
4043 - CONFIG_SYS_CCSRBAR_PHYS:
4044 Physical address of CCSR. CCSR can be relocated to a new
4045 physical address, if desired. In this case, this macro should
4046 be set to that address. Otherwise, it should be set to the
4047 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
4048 is typically relocated on 36-bit builds. It is recommended
4049 that this macro be defined via the _HIGH and _LOW macros:
4051 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
4052 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
4054 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
4055 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
4056 either 0 (32-bit build) or 0xF (36-bit build). This macro is
4057 used in assembly code, so it must not contain typecasts or
4058 integer size suffixes (e.g. "ULL").
4060 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
4061 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
4062 used in assembly code, so it must not contain typecasts or
4063 integer size suffixes (e.g. "ULL").
4065 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
4066 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
4067 forced to a value that ensures that CCSR is not relocated.
4069 - Floppy Disk Support:
4070 CONFIG_SYS_FDC_DRIVE_NUMBER
4072 the default drive number (default value 0)
4074 CONFIG_SYS_ISA_IO_STRIDE
4076 defines the spacing between FDC chipset registers
4079 CONFIG_SYS_ISA_IO_OFFSET
4081 defines the offset of register from address. It
4082 depends on which part of the data bus is connected to
4083 the FDC chipset. (default value 0)
4085 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
4086 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
4089 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
4090 fdc_hw_init() is called at the beginning of the FDC
4091 setup. fdc_hw_init() must be provided by the board
4092 source code. It is used to make hardware-dependent
4096 Most IDE controllers were designed to be connected with PCI
4097 interface. Only few of them were designed for AHB interface.
4098 When software is doing ATA command and data transfer to
4099 IDE devices through IDE-AHB controller, some additional
4100 registers accessing to these kind of IDE-AHB controller
4103 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
4104 DO NOT CHANGE unless you know exactly what you're
4105 doing! (11-4) [MPC8xx/82xx systems only]
4107 - CONFIG_SYS_INIT_RAM_ADDR:
4109 Start address of memory area that can be used for
4110 initial data and stack; please note that this must be
4111 writable memory that is working WITHOUT special
4112 initialization, i. e. you CANNOT use normal RAM which
4113 will become available only after programming the
4114 memory controller and running certain initialization
4117 U-Boot uses the following memory types:
4118 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
4119 - MPC824X: data cache
4120 - PPC4xx: data cache
4122 - CONFIG_SYS_GBL_DATA_OFFSET:
4124 Offset of the initial data structure in the memory
4125 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
4126 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
4127 data is located at the end of the available space
4128 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
4129 GENERATED_GBL_DATA_SIZE), and the initial stack is just
4130 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
4131 CONFIG_SYS_GBL_DATA_OFFSET) downward.
4134 On the MPC824X (or other systems that use the data
4135 cache for initial memory) the address chosen for
4136 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
4137 point to an otherwise UNUSED address space between
4138 the top of RAM and the start of the PCI space.
4140 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
4142 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
4144 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
4146 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
4148 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
4150 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
4152 - CONFIG_SYS_OR_TIMING_SDRAM:
4155 - CONFIG_SYS_MAMR_PTA:
4156 periodic timer for refresh
4158 - CONFIG_SYS_DER: Debug Event Register (37-47)
4160 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
4161 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
4162 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
4163 CONFIG_SYS_BR1_PRELIM:
4164 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
4166 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
4167 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
4168 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
4169 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
4171 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
4172 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
4173 Machine Mode Register and Memory Periodic Timer
4174 Prescaler definitions (SDRAM timing)
4176 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
4177 enable I2C microcode relocation patch (MPC8xx);
4178 define relocation offset in DPRAM [DSP2]
4180 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
4181 enable SMC microcode relocation patch (MPC8xx);
4182 define relocation offset in DPRAM [SMC1]
4184 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
4185 enable SPI microcode relocation patch (MPC8xx);
4186 define relocation offset in DPRAM [SCC4]
4188 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
4189 Offset of the bootmode word in DPRAM used by post
4190 (Power On Self Tests). This definition overrides
4191 #define'd default value in commproc.h resp.
4194 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
4195 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
4196 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
4197 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
4198 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
4199 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
4200 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
4201 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
4202 Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
4204 - CONFIG_PCI_DISABLE_PCIE:
4205 Disable PCI-Express on systems where it is supported but not
4208 - CONFIG_PCI_ENUM_ONLY
4209 Only scan through and get the devices on the buses.
4210 Don't do any setup work, presumably because someone or
4211 something has already done it, and we don't need to do it
4212 a second time. Useful for platforms that are pre-booted
4213 by coreboot or similar.
4215 - CONFIG_PCI_INDIRECT_BRIDGE:
4216 Enable support for indirect PCI bridges.
4219 Chip has SRIO or not
4222 Board has SRIO 1 port available
4225 Board has SRIO 2 port available
4227 - CONFIG_SRIO_PCIE_BOOT_MASTER
4228 Board can support master function for Boot from SRIO and PCIE
4230 - CONFIG_SYS_SRIOn_MEM_VIRT:
4231 Virtual Address of SRIO port 'n' memory region
4233 - CONFIG_SYS_SRIOn_MEM_PHYS:
4234 Physical Address of SRIO port 'n' memory region
4236 - CONFIG_SYS_SRIOn_MEM_SIZE:
4237 Size of SRIO port 'n' memory region
4239 - CONFIG_SYS_NAND_BUSWIDTH_16BIT
4240 Defined to tell the NAND controller that the NAND chip is using
4242 Not all NAND drivers use this symbol.
4243 Example of drivers that use it:
4244 - drivers/mtd/nand/ndfc.c
4245 - drivers/mtd/nand/mxc_nand.c
4247 - CONFIG_SYS_NDFC_EBC0_CFG
4248 Sets the EBC0_CFG register for the NDFC. If not defined
4249 a default value will be used.
4252 Get DDR timing information from an I2C EEPROM. Common
4253 with pluggable memory modules such as SODIMMs
4256 I2C address of the SPD EEPROM
4258 - CONFIG_SYS_SPD_BUS_NUM
4259 If SPD EEPROM is on an I2C bus other than the first
4260 one, specify here. Note that the value must resolve
4261 to something your driver can deal with.
4263 - CONFIG_SYS_DDR_RAW_TIMING
4264 Get DDR timing information from other than SPD. Common with
4265 soldered DDR chips onboard without SPD. DDR raw timing
4266 parameters are extracted from datasheet and hard-coded into
4267 header files or board specific files.
4269 - CONFIG_FSL_DDR_INTERACTIVE
4270 Enable interactive DDR debugging. See doc/README.fsl-ddr.
4272 - CONFIG_FSL_DDR_SYNC_REFRESH
4273 Enable sync of refresh for multiple controllers.
4275 - CONFIG_FSL_DDR_BIST
4276 Enable built-in memory test for Freescale DDR controllers.
4278 - CONFIG_SYS_83XX_DDR_USES_CS0
4279 Only for 83xx systems. If specified, then DDR should
4280 be configured using CS0 and CS1 instead of CS2 and CS3.
4282 - CONFIG_ETHER_ON_FEC[12]
4283 Define to enable FEC[12] on a 8xx series processor.
4285 - CONFIG_FEC[12]_PHY
4286 Define to the hardcoded PHY address which corresponds
4287 to the given FEC; i. e.
4288 #define CONFIG_FEC1_PHY 4
4289 means that the PHY with address 4 is connected to FEC1
4291 When set to -1, means to probe for first available.
4293 - CONFIG_FEC[12]_PHY_NORXERR
4294 The PHY does not have a RXERR line (RMII only).
4295 (so program the FEC to ignore it).
4298 Enable RMII mode for all FECs.
4299 Note that this is a global option, we can't
4300 have one FEC in standard MII mode and another in RMII mode.
4302 - CONFIG_CRC32_VERIFY
4303 Add a verify option to the crc32 command.
4306 => crc32 -v <address> <count> <crc32>
4308 Where address/count indicate a memory area
4309 and crc32 is the correct crc32 which the
4313 Add the "loopw" memory command. This only takes effect if
4314 the memory commands are activated globally (CONFIG_CMD_MEM).
4317 Add the "mdc" and "mwc" memory commands. These are cyclic
4322 This command will print 4 bytes (10,11,12,13) each 500 ms.
4324 => mwc.l 100 12345678 10
4325 This command will write 12345678 to address 100 all 10 ms.
4327 This only takes effect if the memory commands are activated
4328 globally (CONFIG_CMD_MEM).
4330 - CONFIG_SKIP_LOWLEVEL_INIT
4331 [ARM, NDS32, MIPS only] If this variable is defined, then certain
4332 low level initializations (like setting up the memory
4333 controller) are omitted and/or U-Boot does not
4334 relocate itself into RAM.
4336 Normally this variable MUST NOT be defined. The only
4337 exception is when U-Boot is loaded (to RAM) by some
4338 other boot loader or by a debugger which performs
4339 these initializations itself.
4341 - CONFIG_SKIP_LOWLEVEL_INIT_ONLY
4342 [ARM926EJ-S only] This allows just the call to lowlevel_init()
4343 to be skipped. The normal CP15 init (such as enabling the
4344 instruction cache) is still performed.
4347 Modifies the behaviour of start.S when compiling a loader
4348 that is executed before the actual U-Boot. E.g. when
4349 compiling a NAND SPL.
4352 Modifies the behaviour of start.S when compiling a loader
4353 that is executed after the SPL and before the actual U-Boot.
4354 It is loaded by the SPL.
4356 - CONFIG_SYS_MPC85XX_NO_RESETVEC
4357 Only for 85xx systems. If this variable is specified, the section
4358 .resetvec is not kept and the section .bootpg is placed in the
4359 previous 4k of the .text section.
4361 - CONFIG_ARCH_MAP_SYSMEM
4362 Generally U-Boot (and in particular the md command) uses
4363 effective address. It is therefore not necessary to regard
4364 U-Boot address as virtual addresses that need to be translated
4365 to physical addresses. However, sandbox requires this, since
4366 it maintains its own little RAM buffer which contains all
4367 addressable memory. This option causes some memory accesses
4368 to be mapped through map_sysmem() / unmap_sysmem().
4370 - CONFIG_X86_RESET_VECTOR
4371 If defined, the x86 reset vector code is included. This is not
4372 needed when U-Boot is running from Coreboot.
4374 - CONFIG_SPL_AM33XX_ENABLE_RTC32K_OSC:
4375 Enables the RTC32K OSC on AM33xx based plattforms
4377 - CONFIG_SYS_NAND_NO_SUBPAGE_WRITE
4378 Option to disable subpage write in NAND driver
4379 driver that uses this:
4380 drivers/mtd/nand/davinci_nand.c
4382 Freescale QE/FMAN Firmware Support:
4383 -----------------------------------
4385 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
4386 loading of "firmware", which is encoded in the QE firmware binary format.
4387 This firmware often needs to be loaded during U-Boot booting, so macros
4388 are used to identify the storage device (NOR flash, SPI, etc) and the address
4391 - CONFIG_SYS_FMAN_FW_ADDR
4392 The address in the storage device where the FMAN microcode is located. The
4393 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4396 - CONFIG_SYS_QE_FW_ADDR
4397 The address in the storage device where the QE microcode is located. The
4398 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4401 - CONFIG_SYS_QE_FMAN_FW_LENGTH
4402 The maximum possible size of the firmware. The firmware binary format
4403 has a field that specifies the actual size of the firmware, but it
4404 might not be possible to read any part of the firmware unless some
4405 local storage is allocated to hold the entire firmware first.
4407 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
4408 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
4409 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
4410 virtual address in NOR flash.
4412 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
4413 Specifies that QE/FMAN firmware is located in NAND flash.
4414 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
4416 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
4417 Specifies that QE/FMAN firmware is located on the primary SD/MMC
4418 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
4420 - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
4421 Specifies that QE/FMAN firmware is located in the remote (master)
4422 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
4423 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
4424 window->master inbound window->master LAW->the ucode address in
4425 master's memory space.
4427 Freescale Layerscape Management Complex Firmware Support:
4428 ---------------------------------------------------------
4429 The Freescale Layerscape Management Complex (MC) supports the loading of
4431 This firmware often needs to be loaded during U-Boot booting, so macros
4432 are used to identify the storage device (NOR flash, SPI, etc) and the address
4435 - CONFIG_FSL_MC_ENET
4436 Enable the MC driver for Layerscape SoCs.
4438 Freescale Layerscape Debug Server Support:
4439 -------------------------------------------
4440 The Freescale Layerscape Debug Server Support supports the loading of
4441 "Debug Server firmware" and triggering SP boot-rom.
4442 This firmware often needs to be loaded during U-Boot booting.
4444 - CONFIG_SYS_MC_RSV_MEM_ALIGN
4445 Define alignment of reserved memory MC requires
4450 In order to achieve reproducible builds, timestamps used in the U-Boot build
4451 process have to be set to a fixed value.
4453 This is done using the SOURCE_DATE_EPOCH environment variable.
4454 SOURCE_DATE_EPOCH is to be set on the build host's shell, not as a configuration
4455 option for U-Boot or an environment variable in U-Boot.
4457 SOURCE_DATE_EPOCH should be set to a number of seconds since the epoch, in UTC.
4459 Building the Software:
4460 ======================
4462 Building U-Boot has been tested in several native build environments
4463 and in many different cross environments. Of course we cannot support
4464 all possibly existing versions of cross development tools in all
4465 (potentially obsolete) versions. In case of tool chain problems we
4466 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
4467 which is extensively used to build and test U-Boot.
4469 If you are not using a native environment, it is assumed that you
4470 have GNU cross compiling tools available in your path. In this case,
4471 you must set the environment variable CROSS_COMPILE in your shell.
4472 Note that no changes to the Makefile or any other source files are
4473 necessary. For example using the ELDK on a 4xx CPU, please enter:
4475 $ CROSS_COMPILE=ppc_4xx-
4476 $ export CROSS_COMPILE
4478 Note: If you wish to generate Windows versions of the utilities in
4479 the tools directory you can use the MinGW toolchain
4480 (http://www.mingw.org). Set your HOST tools to the MinGW
4481 toolchain and execute 'make tools'. For example:
4483 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
4485 Binaries such as tools/mkimage.exe will be created which can
4486 be executed on computers running Windows.
4488 U-Boot is intended to be simple to build. After installing the
4489 sources you must configure U-Boot for one specific board type. This
4494 where "NAME_defconfig" is the name of one of the existing configu-
4495 rations; see boards.cfg for supported names.
4497 Note: for some board special configuration names may exist; check if
4498 additional information is available from the board vendor; for
4499 instance, the TQM823L systems are available without (standard)
4500 or with LCD support. You can select such additional "features"
4501 when choosing the configuration, i. e.
4503 make TQM823L_defconfig
4504 - will configure for a plain TQM823L, i. e. no LCD support
4506 make TQM823L_LCD_defconfig
4507 - will configure for a TQM823L with U-Boot console on LCD
4512 Finally, type "make all", and you should get some working U-Boot
4513 images ready for download to / installation on your system:
4515 - "u-boot.bin" is a raw binary image
4516 - "u-boot" is an image in ELF binary format
4517 - "u-boot.srec" is in Motorola S-Record format
4519 By default the build is performed locally and the objects are saved
4520 in the source directory. One of the two methods can be used to change
4521 this behavior and build U-Boot to some external directory:
4523 1. Add O= to the make command line invocations:
4525 make O=/tmp/build distclean
4526 make O=/tmp/build NAME_defconfig
4527 make O=/tmp/build all
4529 2. Set environment variable KBUILD_OUTPUT to point to the desired location:
4531 export KBUILD_OUTPUT=/tmp/build
4536 Note that the command line "O=" setting overrides the KBUILD_OUTPUT environment
4540 Please be aware that the Makefiles assume you are using GNU make, so
4541 for instance on NetBSD you might need to use "gmake" instead of
4545 If the system board that you have is not listed, then you will need
4546 to port U-Boot to your hardware platform. To do this, follow these
4549 1. Create a new directory to hold your board specific code. Add any
4550 files you need. In your board directory, you will need at least
4551 the "Makefile" and a "<board>.c".
4552 2. Create a new configuration file "include/configs/<board>.h" for
4554 3. If you're porting U-Boot to a new CPU, then also create a new
4555 directory to hold your CPU specific code. Add any files you need.
4556 4. Run "make <board>_defconfig" with your new name.
4557 5. Type "make", and you should get a working "u-boot.srec" file
4558 to be installed on your target system.
4559 6. Debug and solve any problems that might arise.
4560 [Of course, this last step is much harder than it sounds.]
4563 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
4564 ==============================================================
4566 If you have modified U-Boot sources (for instance added a new board
4567 or support for new devices, a new CPU, etc.) you are expected to
4568 provide feedback to the other developers. The feedback normally takes
4569 the form of a "patch", i. e. a context diff against a certain (latest
4570 official or latest in the git repository) version of U-Boot sources.
4572 But before you submit such a patch, please verify that your modifi-
4573 cation did not break existing code. At least make sure that *ALL* of
4574 the supported boards compile WITHOUT ANY compiler warnings. To do so,
4575 just run the buildman script (tools/buildman/buildman), which will
4576 configure and build U-Boot for ALL supported system. Be warned, this
4577 will take a while. Please see the buildman README, or run 'buildman -H'
4581 See also "U-Boot Porting Guide" below.
4584 Monitor Commands - Overview:
4585 ============================
4587 go - start application at address 'addr'
4588 run - run commands in an environment variable
4589 bootm - boot application image from memory
4590 bootp - boot image via network using BootP/TFTP protocol
4591 bootz - boot zImage from memory
4592 tftpboot- boot image via network using TFTP protocol
4593 and env variables "ipaddr" and "serverip"
4594 (and eventually "gatewayip")
4595 tftpput - upload a file via network using TFTP protocol
4596 rarpboot- boot image via network using RARP/TFTP protocol
4597 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
4598 loads - load S-Record file over serial line
4599 loadb - load binary file over serial line (kermit mode)
4601 mm - memory modify (auto-incrementing)
4602 nm - memory modify (constant address)
4603 mw - memory write (fill)
4605 cmp - memory compare
4606 crc32 - checksum calculation
4607 i2c - I2C sub-system
4608 sspi - SPI utility commands
4609 base - print or set address offset
4610 printenv- print environment variables
4611 setenv - set environment variables
4612 saveenv - save environment variables to persistent storage
4613 protect - enable or disable FLASH write protection
4614 erase - erase FLASH memory
4615 flinfo - print FLASH memory information
4616 nand - NAND memory operations (see doc/README.nand)
4617 bdinfo - print Board Info structure
4618 iminfo - print header information for application image
4619 coninfo - print console devices and informations
4620 ide - IDE sub-system
4621 loop - infinite loop on address range
4622 loopw - infinite write loop on address range
4623 mtest - simple RAM test
4624 icache - enable or disable instruction cache
4625 dcache - enable or disable data cache
4626 reset - Perform RESET of the CPU
4627 echo - echo args to console
4628 version - print monitor version
4629 help - print online help
4630 ? - alias for 'help'
4633 Monitor Commands - Detailed Description:
4634 ========================================
4638 For now: just type "help <command>".
4641 Environment Variables:
4642 ======================
4644 U-Boot supports user configuration using Environment Variables which
4645 can be made persistent by saving to Flash memory.
4647 Environment Variables are set using "setenv", printed using
4648 "printenv", and saved to Flash using "saveenv". Using "setenv"
4649 without a value can be used to delete a variable from the
4650 environment. As long as you don't save the environment you are
4651 working with an in-memory copy. In case the Flash area containing the
4652 environment is erased by accident, a default environment is provided.
4654 Some configuration options can be set using Environment Variables.
4656 List of environment variables (most likely not complete):
4658 baudrate - see CONFIG_BAUDRATE
4660 bootdelay - see CONFIG_BOOTDELAY
4662 bootcmd - see CONFIG_BOOTCOMMAND
4664 bootargs - Boot arguments when booting an RTOS image
4666 bootfile - Name of the image to load with TFTP
4668 bootm_low - Memory range available for image processing in the bootm
4669 command can be restricted. This variable is given as
4670 a hexadecimal number and defines lowest address allowed
4671 for use by the bootm command. See also "bootm_size"
4672 environment variable. Address defined by "bootm_low" is
4673 also the base of the initial memory mapping for the Linux
4674 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
4677 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
4678 This variable is given as a hexadecimal number and it
4679 defines the size of the memory region starting at base
4680 address bootm_low that is accessible by the Linux kernel
4681 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
4682 as the default value if it is defined, and bootm_size is
4685 bootm_size - Memory range available for image processing in the bootm
4686 command can be restricted. This variable is given as
4687 a hexadecimal number and defines the size of the region
4688 allowed for use by the bootm command. See also "bootm_low"
4689 environment variable.
4691 updatefile - Location of the software update file on a TFTP server, used
4692 by the automatic software update feature. Please refer to
4693 documentation in doc/README.update for more details.
4695 autoload - if set to "no" (any string beginning with 'n'),
4696 "bootp" will just load perform a lookup of the
4697 configuration from the BOOTP server, but not try to
4698 load any image using TFTP
4700 autostart - if set to "yes", an image loaded using the "bootp",
4701 "rarpboot", "tftpboot" or "diskboot" commands will
4702 be automatically started (by internally calling
4705 If set to "no", a standalone image passed to the
4706 "bootm" command will be copied to the load address
4707 (and eventually uncompressed), but NOT be started.
4708 This can be used to load and uncompress arbitrary
4711 fdt_high - if set this restricts the maximum address that the
4712 flattened device tree will be copied into upon boot.
4713 For example, if you have a system with 1 GB memory
4714 at physical address 0x10000000, while Linux kernel
4715 only recognizes the first 704 MB as low memory, you
4716 may need to set fdt_high as 0x3C000000 to have the
4717 device tree blob be copied to the maximum address
4718 of the 704 MB low memory, so that Linux kernel can
4719 access it during the boot procedure.
4721 If this is set to the special value 0xFFFFFFFF then
4722 the fdt will not be copied at all on boot. For this
4723 to work it must reside in writable memory, have
4724 sufficient padding on the end of it for u-boot to
4725 add the information it needs into it, and the memory
4726 must be accessible by the kernel.
4728 fdtcontroladdr- if set this is the address of the control flattened
4729 device tree used by U-Boot when CONFIG_OF_CONTROL is
4732 i2cfast - (PPC405GP|PPC405EP only)
4733 if set to 'y' configures Linux I2C driver for fast
4734 mode (400kHZ). This environment variable is used in
4735 initialization code. So, for changes to be effective
4736 it must be saved and board must be reset.
4738 initrd_high - restrict positioning of initrd images:
4739 If this variable is not set, initrd images will be
4740 copied to the highest possible address in RAM; this
4741 is usually what you want since it allows for
4742 maximum initrd size. If for some reason you want to
4743 make sure that the initrd image is loaded below the
4744 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
4745 variable to a value of "no" or "off" or "0".
4746 Alternatively, you can set it to a maximum upper
4747 address to use (U-Boot will still check that it
4748 does not overwrite the U-Boot stack and data).
4750 For instance, when you have a system with 16 MB
4751 RAM, and want to reserve 4 MB from use by Linux,
4752 you can do this by adding "mem=12M" to the value of
4753 the "bootargs" variable. However, now you must make
4754 sure that the initrd image is placed in the first
4755 12 MB as well - this can be done with
4757 setenv initrd_high 00c00000
4759 If you set initrd_high to 0xFFFFFFFF, this is an
4760 indication to U-Boot that all addresses are legal
4761 for the Linux kernel, including addresses in flash
4762 memory. In this case U-Boot will NOT COPY the
4763 ramdisk at all. This may be useful to reduce the
4764 boot time on your system, but requires that this
4765 feature is supported by your Linux kernel.
4767 ipaddr - IP address; needed for tftpboot command
4769 loadaddr - Default load address for commands like "bootp",
4770 "rarpboot", "tftpboot", "loadb" or "diskboot"
4772 loads_echo - see CONFIG_LOADS_ECHO
4774 serverip - TFTP server IP address; needed for tftpboot command
4776 bootretry - see CONFIG_BOOT_RETRY_TIME
4778 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
4780 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
4782 ethprime - controls which interface is used first.
4784 ethact - controls which interface is currently active.
4785 For example you can do the following
4787 => setenv ethact FEC
4788 => ping 192.168.0.1 # traffic sent on FEC
4789 => setenv ethact SCC
4790 => ping 10.0.0.1 # traffic sent on SCC
4792 ethrotate - When set to "no" U-Boot does not go through all
4793 available network interfaces.
4794 It just stays at the currently selected interface.
4796 netretry - When set to "no" each network operation will
4797 either succeed or fail without retrying.
4798 When set to "once" the network operation will
4799 fail when all the available network interfaces
4800 are tried once without success.
4801 Useful on scripts which control the retry operation
4804 npe_ucode - set load address for the NPE microcode
4806 silent_linux - If set then Linux will be told to boot silently, by
4807 changing the console to be empty. If "yes" it will be
4808 made silent. If "no" it will not be made silent. If
4809 unset, then it will be made silent if the U-Boot console
4812 tftpsrcp - If this is set, the value is used for TFTP's
4815 tftpdstp - If this is set, the value is used for TFTP's UDP
4816 destination port instead of the Well Know Port 69.
4818 tftpblocksize - Block size to use for TFTP transfers; if not set,
4819 we use the TFTP server's default block size
4821 tftptimeout - Retransmission timeout for TFTP packets (in milli-
4822 seconds, minimum value is 1000 = 1 second). Defines
4823 when a packet is considered to be lost so it has to
4824 be retransmitted. The default is 5000 = 5 seconds.
4825 Lowering this value may make downloads succeed
4826 faster in networks with high packet loss rates or
4827 with unreliable TFTP servers.
4829 tftptimeoutcountmax - maximum count of TFTP timeouts (no
4830 unit, minimum value = 0). Defines how many timeouts
4831 can happen during a single file transfer before that
4832 transfer is aborted. The default is 10, and 0 means
4833 'no timeouts allowed'. Increasing this value may help
4834 downloads succeed with high packet loss rates, or with
4835 unreliable TFTP servers or client hardware.
4837 vlan - When set to a value < 4095 the traffic over
4838 Ethernet is encapsulated/received over 802.1q
4841 bootpretryperiod - Period during which BOOTP/DHCP sends retries.
4842 Unsigned value, in milliseconds. If not set, the period will
4843 be either the default (28000), or a value based on
4844 CONFIG_NET_RETRY_COUNT, if defined. This value has
4845 precedence over the valu based on CONFIG_NET_RETRY_COUNT.
4847 The following image location variables contain the location of images
4848 used in booting. The "Image" column gives the role of the image and is
4849 not an environment variable name. The other columns are environment
4850 variable names. "File Name" gives the name of the file on a TFTP
4851 server, "RAM Address" gives the location in RAM the image will be
4852 loaded to, and "Flash Location" gives the image's address in NOR
4853 flash or offset in NAND flash.
4855 *Note* - these variables don't have to be defined for all boards, some
4856 boards currently use other variables for these purposes, and some
4857 boards use these variables for other purposes.
4859 Image File Name RAM Address Flash Location
4860 ----- --------- ----------- --------------
4861 u-boot u-boot u-boot_addr_r u-boot_addr
4862 Linux kernel bootfile kernel_addr_r kernel_addr
4863 device tree blob fdtfile fdt_addr_r fdt_addr
4864 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
4866 The following environment variables may be used and automatically
4867 updated by the network boot commands ("bootp" and "rarpboot"),
4868 depending the information provided by your boot server:
4870 bootfile - see above
4871 dnsip - IP address of your Domain Name Server
4872 dnsip2 - IP address of your secondary Domain Name Server
4873 gatewayip - IP address of the Gateway (Router) to use
4874 hostname - Target hostname
4876 netmask - Subnet Mask
4877 rootpath - Pathname of the root filesystem on the NFS server
4878 serverip - see above
4881 There are two special Environment Variables:
4883 serial# - contains hardware identification information such
4884 as type string and/or serial number
4885 ethaddr - Ethernet address
4887 These variables can be set only once (usually during manufacturing of
4888 the board). U-Boot refuses to delete or overwrite these variables
4889 once they have been set once.
4892 Further special Environment Variables:
4894 ver - Contains the U-Boot version string as printed
4895 with the "version" command. This variable is
4896 readonly (see CONFIG_VERSION_VARIABLE).
4899 Please note that changes to some configuration parameters may take
4900 only effect after the next boot (yes, that's just like Windoze :-).
4903 Callback functions for environment variables:
4904 ---------------------------------------------
4906 For some environment variables, the behavior of u-boot needs to change
4907 when their values are changed. This functionality allows functions to
4908 be associated with arbitrary variables. On creation, overwrite, or
4909 deletion, the callback will provide the opportunity for some side
4910 effect to happen or for the change to be rejected.
4912 The callbacks are named and associated with a function using the
4913 U_BOOT_ENV_CALLBACK macro in your board or driver code.
4915 These callbacks are associated with variables in one of two ways. The
4916 static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC
4917 in the board configuration to a string that defines a list of
4918 associations. The list must be in the following format:
4920 entry = variable_name[:callback_name]
4923 If the callback name is not specified, then the callback is deleted.
4924 Spaces are also allowed anywhere in the list.
4926 Callbacks can also be associated by defining the ".callbacks" variable
4927 with the same list format above. Any association in ".callbacks" will
4928 override any association in the static list. You can define
4929 CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the
4930 ".callbacks" environment variable in the default or embedded environment.
4932 If CONFIG_REGEX is defined, the variable_name above is evaluated as a
4933 regular expression. This allows multiple variables to be connected to
4934 the same callback without explicitly listing them all out.
4937 Command Line Parsing:
4938 =====================
4940 There are two different command line parsers available with U-Boot:
4941 the old "simple" one, and the much more powerful "hush" shell:
4943 Old, simple command line parser:
4944 --------------------------------
4946 - supports environment variables (through setenv / saveenv commands)
4947 - several commands on one line, separated by ';'
4948 - variable substitution using "... ${name} ..." syntax
4949 - special characters ('$', ';') can be escaped by prefixing with '\',
4951 setenv bootcmd bootm \${address}
4952 - You can also escape text by enclosing in single apostrophes, for example:
4953 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
4958 - similar to Bourne shell, with control structures like
4959 if...then...else...fi, for...do...done; while...do...done,
4960 until...do...done, ...
4961 - supports environment ("global") variables (through setenv / saveenv
4962 commands) and local shell variables (through standard shell syntax
4963 "name=value"); only environment variables can be used with "run"
4969 (1) If a command line (or an environment variable executed by a "run"
4970 command) contains several commands separated by semicolon, and
4971 one of these commands fails, then the remaining commands will be
4974 (2) If you execute several variables with one call to run (i. e.
4975 calling run with a list of variables as arguments), any failing
4976 command will cause "run" to terminate, i. e. the remaining
4977 variables are not executed.
4979 Note for Redundant Ethernet Interfaces:
4980 =======================================
4982 Some boards come with redundant Ethernet interfaces; U-Boot supports
4983 such configurations and is capable of automatic selection of a
4984 "working" interface when needed. MAC assignment works as follows:
4986 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
4987 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
4988 "eth1addr" (=>eth1), "eth2addr", ...
4990 If the network interface stores some valid MAC address (for instance
4991 in SROM), this is used as default address if there is NO correspon-
4992 ding setting in the environment; if the corresponding environment
4993 variable is set, this overrides the settings in the card; that means:
4995 o If the SROM has a valid MAC address, and there is no address in the
4996 environment, the SROM's address is used.
4998 o If there is no valid address in the SROM, and a definition in the
4999 environment exists, then the value from the environment variable is
5002 o If both the SROM and the environment contain a MAC address, and
5003 both addresses are the same, this MAC address is used.
5005 o If both the SROM and the environment contain a MAC address, and the
5006 addresses differ, the value from the environment is used and a
5009 o If neither SROM nor the environment contain a MAC address, an error
5010 is raised. If CONFIG_NET_RANDOM_ETHADDR is defined, then in this case
5011 a random, locally-assigned MAC is used.
5013 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
5014 will be programmed into hardware as part of the initialization process. This
5015 may be skipped by setting the appropriate 'ethmacskip' environment variable.
5016 The naming convention is as follows:
5017 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
5022 U-Boot is capable of booting (and performing other auxiliary operations on)
5023 images in two formats:
5025 New uImage format (FIT)
5026 -----------------------
5028 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
5029 to Flattened Device Tree). It allows the use of images with multiple
5030 components (several kernels, ramdisks, etc.), with contents protected by
5031 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
5037 Old image format is based on binary files which can be basically anything,
5038 preceded by a special header; see the definitions in include/image.h for
5039 details; basically, the header defines the following image properties:
5041 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
5042 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
5043 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
5044 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
5046 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
5047 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
5048 Currently supported: ARM, AVR32, Intel x86, MIPS, NDS32, Nios II, PowerPC).
5049 * Compression Type (uncompressed, gzip, bzip2)
5055 The header is marked by a special Magic Number, and both the header
5056 and the data portions of the image are secured against corruption by
5063 Although U-Boot should support any OS or standalone application
5064 easily, the main focus has always been on Linux during the design of
5067 U-Boot includes many features that so far have been part of some
5068 special "boot loader" code within the Linux kernel. Also, any
5069 "initrd" images to be used are no longer part of one big Linux image;
5070 instead, kernel and "initrd" are separate images. This implementation
5071 serves several purposes:
5073 - the same features can be used for other OS or standalone
5074 applications (for instance: using compressed images to reduce the
5075 Flash memory footprint)
5077 - it becomes much easier to port new Linux kernel versions because
5078 lots of low-level, hardware dependent stuff are done by U-Boot
5080 - the same Linux kernel image can now be used with different "initrd"
5081 images; of course this also means that different kernel images can
5082 be run with the same "initrd". This makes testing easier (you don't
5083 have to build a new "zImage.initrd" Linux image when you just
5084 change a file in your "initrd"). Also, a field-upgrade of the
5085 software is easier now.
5091 Porting Linux to U-Boot based systems:
5092 ---------------------------------------
5094 U-Boot cannot save you from doing all the necessary modifications to
5095 configure the Linux device drivers for use with your target hardware
5096 (no, we don't intend to provide a full virtual machine interface to
5099 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
5101 Just make sure your machine specific header file (for instance
5102 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
5103 Information structure as we define in include/asm-<arch>/u-boot.h,
5104 and make sure that your definition of IMAP_ADDR uses the same value
5105 as your U-Boot configuration in CONFIG_SYS_IMMR.
5107 Note that U-Boot now has a driver model, a unified model for drivers.
5108 If you are adding a new driver, plumb it into driver model. If there
5109 is no uclass available, you are encouraged to create one. See
5113 Configuring the Linux kernel:
5114 -----------------------------
5116 No specific requirements for U-Boot. Make sure you have some root
5117 device (initial ramdisk, NFS) for your target system.
5120 Building a Linux Image:
5121 -----------------------
5123 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
5124 not used. If you use recent kernel source, a new build target
5125 "uImage" will exist which automatically builds an image usable by
5126 U-Boot. Most older kernels also have support for a "pImage" target,
5127 which was introduced for our predecessor project PPCBoot and uses a
5128 100% compatible format.
5132 make TQM850L_defconfig
5137 The "uImage" build target uses a special tool (in 'tools/mkimage') to
5138 encapsulate a compressed Linux kernel image with header information,
5139 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
5141 * build a standard "vmlinux" kernel image (in ELF binary format):
5143 * convert the kernel into a raw binary image:
5145 ${CROSS_COMPILE}-objcopy -O binary \
5146 -R .note -R .comment \
5147 -S vmlinux linux.bin
5149 * compress the binary image:
5153 * package compressed binary image for U-Boot:
5155 mkimage -A ppc -O linux -T kernel -C gzip \
5156 -a 0 -e 0 -n "Linux Kernel Image" \
5157 -d linux.bin.gz uImage
5160 The "mkimage" tool can also be used to create ramdisk images for use
5161 with U-Boot, either separated from the Linux kernel image, or
5162 combined into one file. "mkimage" encapsulates the images with a 64
5163 byte header containing information about target architecture,
5164 operating system, image type, compression method, entry points, time
5165 stamp, CRC32 checksums, etc.
5167 "mkimage" can be called in two ways: to verify existing images and
5168 print the header information, or to build new images.
5170 In the first form (with "-l" option) mkimage lists the information
5171 contained in the header of an existing U-Boot image; this includes
5172 checksum verification:
5174 tools/mkimage -l image
5175 -l ==> list image header information
5177 The second form (with "-d" option) is used to build a U-Boot image
5178 from a "data file" which is used as image payload:
5180 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
5181 -n name -d data_file image
5182 -A ==> set architecture to 'arch'
5183 -O ==> set operating system to 'os'
5184 -T ==> set image type to 'type'
5185 -C ==> set compression type 'comp'
5186 -a ==> set load address to 'addr' (hex)
5187 -e ==> set entry point to 'ep' (hex)
5188 -n ==> set image name to 'name'
5189 -d ==> use image data from 'datafile'
5191 Right now, all Linux kernels for PowerPC systems use the same load
5192 address (0x00000000), but the entry point address depends on the
5195 - 2.2.x kernels have the entry point at 0x0000000C,
5196 - 2.3.x and later kernels have the entry point at 0x00000000.
5198 So a typical call to build a U-Boot image would read:
5200 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5201 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
5202 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
5203 > examples/uImage.TQM850L
5204 Image Name: 2.4.4 kernel for TQM850L
5205 Created: Wed Jul 19 02:34:59 2000
5206 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5207 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5208 Load Address: 0x00000000
5209 Entry Point: 0x00000000
5211 To verify the contents of the image (or check for corruption):
5213 -> tools/mkimage -l examples/uImage.TQM850L
5214 Image Name: 2.4.4 kernel for TQM850L
5215 Created: Wed Jul 19 02:34:59 2000
5216 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5217 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5218 Load Address: 0x00000000
5219 Entry Point: 0x00000000
5221 NOTE: for embedded systems where boot time is critical you can trade
5222 speed for memory and install an UNCOMPRESSED image instead: this
5223 needs more space in Flash, but boots much faster since it does not
5224 need to be uncompressed:
5226 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
5227 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5228 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
5229 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
5230 > examples/uImage.TQM850L-uncompressed
5231 Image Name: 2.4.4 kernel for TQM850L
5232 Created: Wed Jul 19 02:34:59 2000
5233 Image Type: PowerPC Linux Kernel Image (uncompressed)
5234 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
5235 Load Address: 0x00000000
5236 Entry Point: 0x00000000
5239 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
5240 when your kernel is intended to use an initial ramdisk:
5242 -> tools/mkimage -n 'Simple Ramdisk Image' \
5243 > -A ppc -O linux -T ramdisk -C gzip \
5244 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
5245 Image Name: Simple Ramdisk Image
5246 Created: Wed Jan 12 14:01:50 2000
5247 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5248 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
5249 Load Address: 0x00000000
5250 Entry Point: 0x00000000
5252 The "dumpimage" is a tool to disassemble images built by mkimage. Its "-i"
5253 option performs the converse operation of the mkimage's second form (the "-d"
5254 option). Given an image built by mkimage, the dumpimage extracts a "data file"
5257 tools/dumpimage -i image -T type -p position data_file
5258 -i ==> extract from the 'image' a specific 'data_file'
5259 -T ==> set image type to 'type'
5260 -p ==> 'position' (starting at 0) of the 'data_file' inside the 'image'
5263 Installing a Linux Image:
5264 -------------------------
5266 To downloading a U-Boot image over the serial (console) interface,
5267 you must convert the image to S-Record format:
5269 objcopy -I binary -O srec examples/image examples/image.srec
5271 The 'objcopy' does not understand the information in the U-Boot
5272 image header, so the resulting S-Record file will be relative to
5273 address 0x00000000. To load it to a given address, you need to
5274 specify the target address as 'offset' parameter with the 'loads'
5277 Example: install the image to address 0x40100000 (which on the
5278 TQM8xxL is in the first Flash bank):
5280 => erase 40100000 401FFFFF
5286 ## Ready for S-Record download ...
5287 ~>examples/image.srec
5288 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
5290 15989 15990 15991 15992
5291 [file transfer complete]
5293 ## Start Addr = 0x00000000
5296 You can check the success of the download using the 'iminfo' command;
5297 this includes a checksum verification so you can be sure no data
5298 corruption happened:
5302 ## Checking Image at 40100000 ...
5303 Image Name: 2.2.13 for initrd on TQM850L
5304 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5305 Data Size: 335725 Bytes = 327 kB = 0 MB
5306 Load Address: 00000000
5307 Entry Point: 0000000c
5308 Verifying Checksum ... OK
5314 The "bootm" command is used to boot an application that is stored in
5315 memory (RAM or Flash). In case of a Linux kernel image, the contents
5316 of the "bootargs" environment variable is passed to the kernel as
5317 parameters. You can check and modify this variable using the
5318 "printenv" and "setenv" commands:
5321 => printenv bootargs
5322 bootargs=root=/dev/ram
5324 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5326 => printenv bootargs
5327 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5330 ## Booting Linux kernel at 40020000 ...
5331 Image Name: 2.2.13 for NFS on TQM850L
5332 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5333 Data Size: 381681 Bytes = 372 kB = 0 MB
5334 Load Address: 00000000
5335 Entry Point: 0000000c
5336 Verifying Checksum ... OK
5337 Uncompressing Kernel Image ... OK
5338 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
5339 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5340 time_init: decrementer frequency = 187500000/60
5341 Calibrating delay loop... 49.77 BogoMIPS
5342 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
5345 If you want to boot a Linux kernel with initial RAM disk, you pass
5346 the memory addresses of both the kernel and the initrd image (PPBCOOT
5347 format!) to the "bootm" command:
5349 => imi 40100000 40200000
5351 ## Checking Image at 40100000 ...
5352 Image Name: 2.2.13 for initrd on TQM850L
5353 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5354 Data Size: 335725 Bytes = 327 kB = 0 MB
5355 Load Address: 00000000
5356 Entry Point: 0000000c
5357 Verifying Checksum ... OK
5359 ## Checking Image at 40200000 ...
5360 Image Name: Simple Ramdisk Image
5361 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5362 Data Size: 566530 Bytes = 553 kB = 0 MB
5363 Load Address: 00000000
5364 Entry Point: 00000000
5365 Verifying Checksum ... OK
5367 => bootm 40100000 40200000
5368 ## Booting Linux kernel at 40100000 ...
5369 Image Name: 2.2.13 for initrd on TQM850L
5370 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5371 Data Size: 335725 Bytes = 327 kB = 0 MB
5372 Load Address: 00000000
5373 Entry Point: 0000000c
5374 Verifying Checksum ... OK
5375 Uncompressing Kernel Image ... OK
5376 ## Loading RAMDisk Image at 40200000 ...
5377 Image Name: Simple Ramdisk Image
5378 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5379 Data Size: 566530 Bytes = 553 kB = 0 MB
5380 Load Address: 00000000
5381 Entry Point: 00000000
5382 Verifying Checksum ... OK
5383 Loading Ramdisk ... OK
5384 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
5385 Boot arguments: root=/dev/ram
5386 time_init: decrementer frequency = 187500000/60
5387 Calibrating delay loop... 49.77 BogoMIPS
5389 RAMDISK: Compressed image found at block 0
5390 VFS: Mounted root (ext2 filesystem).
5394 Boot Linux and pass a flat device tree:
5397 First, U-Boot must be compiled with the appropriate defines. See the section
5398 titled "Linux Kernel Interface" above for a more in depth explanation. The
5399 following is an example of how to start a kernel and pass an updated
5405 oft=oftrees/mpc8540ads.dtb
5406 => tftp $oftaddr $oft
5407 Speed: 1000, full duplex
5409 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
5410 Filename 'oftrees/mpc8540ads.dtb'.
5411 Load address: 0x300000
5414 Bytes transferred = 4106 (100a hex)
5415 => tftp $loadaddr $bootfile
5416 Speed: 1000, full duplex
5418 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
5420 Load address: 0x200000
5421 Loading:############
5423 Bytes transferred = 1029407 (fb51f hex)
5428 => bootm $loadaddr - $oftaddr
5429 ## Booting image at 00200000 ...
5430 Image Name: Linux-2.6.17-dirty
5431 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5432 Data Size: 1029343 Bytes = 1005.2 kB
5433 Load Address: 00000000
5434 Entry Point: 00000000
5435 Verifying Checksum ... OK
5436 Uncompressing Kernel Image ... OK
5437 Booting using flat device tree at 0x300000
5438 Using MPC85xx ADS machine description
5439 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
5443 More About U-Boot Image Types:
5444 ------------------------------
5446 U-Boot supports the following image types:
5448 "Standalone Programs" are directly runnable in the environment
5449 provided by U-Boot; it is expected that (if they behave
5450 well) you can continue to work in U-Boot after return from
5451 the Standalone Program.
5452 "OS Kernel Images" are usually images of some Embedded OS which
5453 will take over control completely. Usually these programs
5454 will install their own set of exception handlers, device
5455 drivers, set up the MMU, etc. - this means, that you cannot
5456 expect to re-enter U-Boot except by resetting the CPU.
5457 "RAMDisk Images" are more or less just data blocks, and their
5458 parameters (address, size) are passed to an OS kernel that is
5460 "Multi-File Images" contain several images, typically an OS
5461 (Linux) kernel image and one or more data images like
5462 RAMDisks. This construct is useful for instance when you want
5463 to boot over the network using BOOTP etc., where the boot
5464 server provides just a single image file, but you want to get
5465 for instance an OS kernel and a RAMDisk image.
5467 "Multi-File Images" start with a list of image sizes, each
5468 image size (in bytes) specified by an "uint32_t" in network
5469 byte order. This list is terminated by an "(uint32_t)0".
5470 Immediately after the terminating 0 follow the images, one by
5471 one, all aligned on "uint32_t" boundaries (size rounded up to
5472 a multiple of 4 bytes).
5474 "Firmware Images" are binary images containing firmware (like
5475 U-Boot or FPGA images) which usually will be programmed to
5478 "Script files" are command sequences that will be executed by
5479 U-Boot's command interpreter; this feature is especially
5480 useful when you configure U-Boot to use a real shell (hush)
5481 as command interpreter.
5483 Booting the Linux zImage:
5484 -------------------------
5486 On some platforms, it's possible to boot Linux zImage. This is done
5487 using the "bootz" command. The syntax of "bootz" command is the same
5488 as the syntax of "bootm" command.
5490 Note, defining the CONFIG_SUPPORT_RAW_INITRD allows user to supply
5491 kernel with raw initrd images. The syntax is slightly different, the
5492 address of the initrd must be augmented by it's size, in the following
5493 format: "<initrd addres>:<initrd size>".
5499 One of the features of U-Boot is that you can dynamically load and
5500 run "standalone" applications, which can use some resources of
5501 U-Boot like console I/O functions or interrupt services.
5503 Two simple examples are included with the sources:
5508 'examples/hello_world.c' contains a small "Hello World" Demo
5509 application; it is automatically compiled when you build U-Boot.
5510 It's configured to run at address 0x00040004, so you can play with it
5514 ## Ready for S-Record download ...
5515 ~>examples/hello_world.srec
5516 1 2 3 4 5 6 7 8 9 10 11 ...
5517 [file transfer complete]
5519 ## Start Addr = 0x00040004
5521 => go 40004 Hello World! This is a test.
5522 ## Starting application at 0x00040004 ...
5533 Hit any key to exit ...
5535 ## Application terminated, rc = 0x0
5537 Another example, which demonstrates how to register a CPM interrupt
5538 handler with the U-Boot code, can be found in 'examples/timer.c'.
5539 Here, a CPM timer is set up to generate an interrupt every second.
5540 The interrupt service routine is trivial, just printing a '.'
5541 character, but this is just a demo program. The application can be
5542 controlled by the following keys:
5544 ? - print current values og the CPM Timer registers
5545 b - enable interrupts and start timer
5546 e - stop timer and disable interrupts
5547 q - quit application
5550 ## Ready for S-Record download ...
5551 ~>examples/timer.srec
5552 1 2 3 4 5 6 7 8 9 10 11 ...
5553 [file transfer complete]
5555 ## Start Addr = 0x00040004
5558 ## Starting application at 0x00040004 ...
5561 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
5564 [q, b, e, ?] Set interval 1000000 us
5567 [q, b, e, ?] ........
5568 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
5571 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
5574 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
5577 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
5579 [q, b, e, ?] ...Stopping timer
5581 [q, b, e, ?] ## Application terminated, rc = 0x0
5587 Over time, many people have reported problems when trying to use the
5588 "minicom" terminal emulation program for serial download. I (wd)
5589 consider minicom to be broken, and recommend not to use it. Under
5590 Unix, I recommend to use C-Kermit for general purpose use (and
5591 especially for kermit binary protocol download ("loadb" command), and
5592 use "cu" for S-Record download ("loads" command). See
5593 http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
5594 for help with kermit.
5597 Nevertheless, if you absolutely want to use it try adding this
5598 configuration to your "File transfer protocols" section:
5600 Name Program Name U/D FullScr IO-Red. Multi
5601 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
5602 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
5608 Starting at version 0.9.2, U-Boot supports NetBSD both as host
5609 (build U-Boot) and target system (boots NetBSD/mpc8xx).
5611 Building requires a cross environment; it is known to work on
5612 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
5613 need gmake since the Makefiles are not compatible with BSD make).
5614 Note that the cross-powerpc package does not install include files;
5615 attempting to build U-Boot will fail because <machine/ansi.h> is
5616 missing. This file has to be installed and patched manually:
5618 # cd /usr/pkg/cross/powerpc-netbsd/include
5620 # ln -s powerpc machine
5621 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
5622 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
5624 Native builds *don't* work due to incompatibilities between native
5625 and U-Boot include files.
5627 Booting assumes that (the first part of) the image booted is a
5628 stage-2 loader which in turn loads and then invokes the kernel
5629 proper. Loader sources will eventually appear in the NetBSD source
5630 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
5631 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
5634 Implementation Internals:
5635 =========================
5637 The following is not intended to be a complete description of every
5638 implementation detail. However, it should help to understand the
5639 inner workings of U-Boot and make it easier to port it to custom
5643 Initial Stack, Global Data:
5644 ---------------------------
5646 The implementation of U-Boot is complicated by the fact that U-Boot
5647 starts running out of ROM (flash memory), usually without access to
5648 system RAM (because the memory controller is not initialized yet).
5649 This means that we don't have writable Data or BSS segments, and BSS
5650 is not initialized as zero. To be able to get a C environment working
5651 at all, we have to allocate at least a minimal stack. Implementation
5652 options for this are defined and restricted by the CPU used: Some CPU
5653 models provide on-chip memory (like the IMMR area on MPC8xx and
5654 MPC826x processors), on others (parts of) the data cache can be
5655 locked as (mis-) used as memory, etc.
5657 Chris Hallinan posted a good summary of these issues to the
5658 U-Boot mailing list:
5660 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
5661 From: "Chris Hallinan" <clh@net1plus.com>
5662 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
5665 Correct me if I'm wrong, folks, but the way I understand it
5666 is this: Using DCACHE as initial RAM for Stack, etc, does not
5667 require any physical RAM backing up the cache. The cleverness
5668 is that the cache is being used as a temporary supply of
5669 necessary storage before the SDRAM controller is setup. It's
5670 beyond the scope of this list to explain the details, but you
5671 can see how this works by studying the cache architecture and
5672 operation in the architecture and processor-specific manuals.
5674 OCM is On Chip Memory, which I believe the 405GP has 4K. It
5675 is another option for the system designer to use as an
5676 initial stack/RAM area prior to SDRAM being available. Either
5677 option should work for you. Using CS 4 should be fine if your
5678 board designers haven't used it for something that would
5679 cause you grief during the initial boot! It is frequently not
5682 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
5683 with your processor/board/system design. The default value
5684 you will find in any recent u-boot distribution in
5685 walnut.h should work for you. I'd set it to a value larger
5686 than your SDRAM module. If you have a 64MB SDRAM module, set
5687 it above 400_0000. Just make sure your board has no resources
5688 that are supposed to respond to that address! That code in
5689 start.S has been around a while and should work as is when
5690 you get the config right.
5695 It is essential to remember this, since it has some impact on the C
5696 code for the initialization procedures:
5698 * Initialized global data (data segment) is read-only. Do not attempt
5701 * Do not use any uninitialized global data (or implicitly initialized
5702 as zero data - BSS segment) at all - this is undefined, initiali-
5703 zation is performed later (when relocating to RAM).
5705 * Stack space is very limited. Avoid big data buffers or things like
5708 Having only the stack as writable memory limits means we cannot use
5709 normal global data to share information between the code. But it
5710 turned out that the implementation of U-Boot can be greatly
5711 simplified by making a global data structure (gd_t) available to all
5712 functions. We could pass a pointer to this data as argument to _all_
5713 functions, but this would bloat the code. Instead we use a feature of
5714 the GCC compiler (Global Register Variables) to share the data: we
5715 place a pointer (gd) to the global data into a register which we
5716 reserve for this purpose.
5718 When choosing a register for such a purpose we are restricted by the
5719 relevant (E)ABI specifications for the current architecture, and by
5720 GCC's implementation.
5722 For PowerPC, the following registers have specific use:
5724 R2: reserved for system use
5725 R3-R4: parameter passing and return values
5726 R5-R10: parameter passing
5727 R13: small data area pointer
5731 (U-Boot also uses R12 as internal GOT pointer. r12
5732 is a volatile register so r12 needs to be reset when
5733 going back and forth between asm and C)
5735 ==> U-Boot will use R2 to hold a pointer to the global data
5737 Note: on PPC, we could use a static initializer (since the
5738 address of the global data structure is known at compile time),
5739 but it turned out that reserving a register results in somewhat
5740 smaller code - although the code savings are not that big (on
5741 average for all boards 752 bytes for the whole U-Boot image,
5742 624 text + 127 data).
5744 On ARM, the following registers are used:
5746 R0: function argument word/integer result
5747 R1-R3: function argument word
5748 R9: platform specific
5749 R10: stack limit (used only if stack checking is enabled)
5750 R11: argument (frame) pointer
5751 R12: temporary workspace
5754 R15: program counter
5756 ==> U-Boot will use R9 to hold a pointer to the global data
5758 Note: on ARM, only R_ARM_RELATIVE relocations are supported.
5760 On Nios II, the ABI is documented here:
5761 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
5763 ==> U-Boot will use gp to hold a pointer to the global data
5765 Note: on Nios II, we give "-G0" option to gcc and don't use gp
5766 to access small data sections, so gp is free.
5768 On NDS32, the following registers are used:
5770 R0-R1: argument/return
5772 R15: temporary register for assembler
5773 R16: trampoline register
5774 R28: frame pointer (FP)
5775 R29: global pointer (GP)
5776 R30: link register (LP)
5777 R31: stack pointer (SP)
5778 PC: program counter (PC)
5780 ==> U-Boot will use R10 to hold a pointer to the global data
5782 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
5783 or current versions of GCC may "optimize" the code too much.
5788 U-Boot runs in system state and uses physical addresses, i.e. the
5789 MMU is not used either for address mapping nor for memory protection.
5791 The available memory is mapped to fixed addresses using the memory
5792 controller. In this process, a contiguous block is formed for each
5793 memory type (Flash, SDRAM, SRAM), even when it consists of several
5794 physical memory banks.
5796 U-Boot is installed in the first 128 kB of the first Flash bank (on
5797 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
5798 booting and sizing and initializing DRAM, the code relocates itself
5799 to the upper end of DRAM. Immediately below the U-Boot code some
5800 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
5801 configuration setting]. Below that, a structure with global Board
5802 Info data is placed, followed by the stack (growing downward).
5804 Additionally, some exception handler code is copied to the low 8 kB
5805 of DRAM (0x00000000 ... 0x00001FFF).
5807 So a typical memory configuration with 16 MB of DRAM could look like
5810 0x0000 0000 Exception Vector code
5813 0x0000 2000 Free for Application Use
5819 0x00FB FF20 Monitor Stack (Growing downward)
5820 0x00FB FFAC Board Info Data and permanent copy of global data
5821 0x00FC 0000 Malloc Arena
5824 0x00FE 0000 RAM Copy of Monitor Code
5825 ... eventually: LCD or video framebuffer
5826 ... eventually: pRAM (Protected RAM - unchanged by reset)
5827 0x00FF FFFF [End of RAM]
5830 System Initialization:
5831 ----------------------
5833 In the reset configuration, U-Boot starts at the reset entry point
5834 (on most PowerPC systems at address 0x00000100). Because of the reset
5835 configuration for CS0# this is a mirror of the on board Flash memory.
5836 To be able to re-map memory U-Boot then jumps to its link address.
5837 To be able to implement the initialization code in C, a (small!)
5838 initial stack is set up in the internal Dual Ported RAM (in case CPUs
5839 which provide such a feature like MPC8xx or MPC8260), or in a locked
5840 part of the data cache. After that, U-Boot initializes the CPU core,
5841 the caches and the SIU.
5843 Next, all (potentially) available memory banks are mapped using a
5844 preliminary mapping. For example, we put them on 512 MB boundaries
5845 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
5846 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
5847 programmed for SDRAM access. Using the temporary configuration, a
5848 simple memory test is run that determines the size of the SDRAM
5851 When there is more than one SDRAM bank, and the banks are of
5852 different size, the largest is mapped first. For equal size, the first
5853 bank (CS2#) is mapped first. The first mapping is always for address
5854 0x00000000, with any additional banks following immediately to create
5855 contiguous memory starting from 0.
5857 Then, the monitor installs itself at the upper end of the SDRAM area
5858 and allocates memory for use by malloc() and for the global Board
5859 Info data; also, the exception vector code is copied to the low RAM
5860 pages, and the final stack is set up.
5862 Only after this relocation will you have a "normal" C environment;
5863 until that you are restricted in several ways, mostly because you are
5864 running from ROM, and because the code will have to be relocated to a
5868 U-Boot Porting Guide:
5869 ----------------------
5871 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
5875 int main(int argc, char *argv[])
5877 sighandler_t no_more_time;
5879 signal(SIGALRM, no_more_time);
5880 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
5882 if (available_money > available_manpower) {
5883 Pay consultant to port U-Boot;
5887 Download latest U-Boot source;
5889 Subscribe to u-boot mailing list;
5892 email("Hi, I am new to U-Boot, how do I get started?");
5895 Read the README file in the top level directory;
5896 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
5897 Read applicable doc/*.README;
5898 Read the source, Luke;
5899 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
5902 if (available_money > toLocalCurrency ($2500))
5905 Add a lot of aggravation and time;
5907 if (a similar board exists) { /* hopefully... */
5908 cp -a board/<similar> board/<myboard>
5909 cp include/configs/<similar>.h include/configs/<myboard>.h
5911 Create your own board support subdirectory;
5912 Create your own board include/configs/<myboard>.h file;
5914 Edit new board/<myboard> files
5915 Edit new include/configs/<myboard>.h
5920 Add / modify source code;
5924 email("Hi, I am having problems...");
5926 Send patch file to the U-Boot email list;
5927 if (reasonable critiques)
5928 Incorporate improvements from email list code review;
5930 Defend code as written;
5936 void no_more_time (int sig)
5945 All contributions to U-Boot should conform to the Linux kernel
5946 coding style; see the file "Documentation/CodingStyle" and the script
5947 "scripts/Lindent" in your Linux kernel source directory.
5949 Source files originating from a different project (for example the
5950 MTD subsystem) are generally exempt from these guidelines and are not
5951 reformatted to ease subsequent migration to newer versions of those
5954 Please note that U-Boot is implemented in C (and to some small parts in
5955 Assembler); no C++ is used, so please do not use C++ style comments (//)
5958 Please also stick to the following formatting rules:
5959 - remove any trailing white space
5960 - use TAB characters for indentation and vertical alignment, not spaces
5961 - make sure NOT to use DOS '\r\n' line feeds
5962 - do not add more than 2 consecutive empty lines to source files
5963 - do not add trailing empty lines to source files
5965 Submissions which do not conform to the standards may be returned
5966 with a request to reformat the changes.
5972 Since the number of patches for U-Boot is growing, we need to
5973 establish some rules. Submissions which do not conform to these rules
5974 may be rejected, even when they contain important and valuable stuff.
5976 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
5978 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
5979 see http://lists.denx.de/mailman/listinfo/u-boot
5981 When you send a patch, please include the following information with
5984 * For bug fixes: a description of the bug and how your patch fixes
5985 this bug. Please try to include a way of demonstrating that the
5986 patch actually fixes something.
5988 * For new features: a description of the feature and your
5991 * A CHANGELOG entry as plaintext (separate from the patch)
5993 * For major contributions, add a MAINTAINERS file with your
5994 information and associated file and directory references.
5996 * When you add support for a new board, don't forget to add a
5997 maintainer e-mail address to the boards.cfg file, too.
5999 * If your patch adds new configuration options, don't forget to
6000 document these in the README file.
6002 * The patch itself. If you are using git (which is *strongly*
6003 recommended) you can easily generate the patch using the
6004 "git format-patch". If you then use "git send-email" to send it to
6005 the U-Boot mailing list, you will avoid most of the common problems
6006 with some other mail clients.
6008 If you cannot use git, use "diff -purN OLD NEW". If your version of
6009 diff does not support these options, then get the latest version of
6012 The current directory when running this command shall be the parent
6013 directory of the U-Boot source tree (i. e. please make sure that
6014 your patch includes sufficient directory information for the
6017 We prefer patches as plain text. MIME attachments are discouraged,
6018 and compressed attachments must not be used.
6020 * If one logical set of modifications affects or creates several
6021 files, all these changes shall be submitted in a SINGLE patch file.
6023 * Changesets that contain different, unrelated modifications shall be
6024 submitted as SEPARATE patches, one patch per changeset.
6029 * Before sending the patch, run the buildman script on your patched
6030 source tree and make sure that no errors or warnings are reported
6031 for any of the boards.
6033 * Keep your modifications to the necessary minimum: A patch
6034 containing several unrelated changes or arbitrary reformats will be
6035 returned with a request to re-formatting / split it.
6037 * If you modify existing code, make sure that your new code does not
6038 add to the memory footprint of the code ;-) Small is beautiful!
6039 When adding new features, these should compile conditionally only
6040 (using #ifdef), and the resulting code with the new feature
6041 disabled must not need more memory than the old code without your
6044 * Remember that there is a size limit of 100 kB per message on the
6045 u-boot mailing list. Bigger patches will be moderated. If they are
6046 reasonable and not too big, they will be acknowledged. But patches
6047 bigger than the size limit should be avoided.