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_IRQ * irqinfo
856 CONFIG_CMD_ITEST Integer/string test of 2 values
857 CONFIG_CMD_JFFS2 * JFFS2 Support
858 CONFIG_CMD_KGDB * kgdb
859 CONFIG_CMD_LDRINFO * ldrinfo (display Blackfin loader)
860 CONFIG_CMD_LINK_LOCAL * link-local IP address auto-configuration
862 CONFIG_CMD_LOADB loadb
863 CONFIG_CMD_LOADS loads
864 CONFIG_CMD_MD5SUM * print md5 message digest
865 (requires CONFIG_CMD_MEMORY and CONFIG_MD5)
866 CONFIG_CMD_MEMINFO * Display detailed memory information
867 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
869 CONFIG_CMD_MEMTEST * mtest
870 CONFIG_CMD_MISC Misc functions like sleep etc
871 CONFIG_CMD_MMC * MMC memory mapped support
872 CONFIG_CMD_MII * MII utility commands
873 CONFIG_CMD_MTDPARTS * MTD partition support
874 CONFIG_CMD_NAND * NAND support
875 CONFIG_CMD_NET bootp, tftpboot, rarpboot
876 CONFIG_CMD_NFS NFS support
877 CONFIG_CMD_PCA953X * PCA953x I2C gpio commands
878 CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command
879 CONFIG_CMD_PCI * pciinfo
880 CONFIG_CMD_PCMCIA * PCMCIA support
881 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
883 CONFIG_CMD_PORTIO * Port I/O
884 CONFIG_CMD_READ * Read raw data from partition
885 CONFIG_CMD_REGINFO * Register dump
886 CONFIG_CMD_RUN run command in env variable
887 CONFIG_CMD_SANDBOX * sb command to access sandbox features
888 CONFIG_CMD_SAVES * save S record dump
889 CONFIG_SCSI * SCSI Support
890 CONFIG_CMD_SDRAM * print SDRAM configuration information
891 (requires CONFIG_CMD_I2C)
892 CONFIG_CMD_SETGETDCR Support for DCR Register access
894 CONFIG_CMD_SF * Read/write/erase SPI NOR flash
895 CONFIG_CMD_SHA1SUM * print sha1 memory digest
896 (requires CONFIG_CMD_MEMORY)
897 CONFIG_CMD_SOFTSWITCH * Soft switch setting command for BF60x
898 CONFIG_CMD_SOURCE "source" command Support
899 CONFIG_CMD_SPI * SPI serial bus support
900 CONFIG_CMD_TFTPSRV * TFTP transfer in server mode
901 CONFIG_CMD_TFTPPUT * TFTP put command (upload)
902 CONFIG_CMD_TIME * run command and report execution time (ARM specific)
903 CONFIG_CMD_TIMER * access to the system tick timer
904 CONFIG_CMD_USB * USB support
905 CONFIG_CMD_CDP * Cisco Discover Protocol support
906 CONFIG_CMD_MFSL * Microblaze FSL support
907 CONFIG_CMD_XIMG Load part of Multi Image
908 CONFIG_CMD_UUID * Generate random UUID or GUID string
910 EXAMPLE: If you want all functions except of network
911 support you can write:
913 #include "config_cmd_all.h"
914 #undef CONFIG_CMD_NET
917 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
919 Note: Don't enable the "icache" and "dcache" commands
920 (configuration option CONFIG_CMD_CACHE) unless you know
921 what you (and your U-Boot users) are doing. Data
922 cache cannot be enabled on systems like the 8xx or
923 8260 (where accesses to the IMMR region must be
924 uncached), and it cannot be disabled on all other
925 systems where we (mis-) use the data cache to hold an
926 initial stack and some data.
929 XXX - this list needs to get updated!
931 - Removal of commands
932 If no commands are needed to boot, you can disable
933 CONFIG_CMDLINE to remove them. In this case, the command line
934 will not be available, and when U-Boot wants to execute the
935 boot command (on start-up) it will call board_run_command()
936 instead. This can reduce image size significantly for very
937 simple boot procedures.
939 - Regular expression support:
941 If this variable is defined, U-Boot is linked against
942 the SLRE (Super Light Regular Expression) library,
943 which adds regex support to some commands, as for
944 example "env grep" and "setexpr".
948 If this variable is defined, U-Boot will use a device tree
949 to configure its devices, instead of relying on statically
950 compiled #defines in the board file. This option is
951 experimental and only available on a few boards. The device
952 tree is available in the global data as gd->fdt_blob.
954 U-Boot needs to get its device tree from somewhere. This can
955 be done using one of the three options below:
958 If this variable is defined, U-Boot will embed a device tree
959 binary in its image. This device tree file should be in the
960 board directory and called <soc>-<board>.dts. The binary file
961 is then picked up in board_init_f() and made available through
962 the global data structure as gd->blob.
965 If this variable is defined, U-Boot will build a device tree
966 binary. It will be called u-boot.dtb. Architecture-specific
967 code will locate it at run-time. Generally this works by:
969 cat u-boot.bin u-boot.dtb >image.bin
971 and in fact, U-Boot does this for you, creating a file called
972 u-boot-dtb.bin which is useful in the common case. You can
973 still use the individual files if you need something more
977 If this variable is defined, U-Boot will use the device tree
978 provided by the board at runtime instead of embedding one with
979 the image. Only boards defining board_fdt_blob_setup() support
980 this option (see include/fdtdec.h file).
984 If this variable is defined, it enables watchdog
985 support for the SoC. There must be support in the SoC
986 specific code for a watchdog. For the 8xx and 8260
987 CPUs, the SIU Watchdog feature is enabled in the SYPCR
988 register. When supported for a specific SoC is
989 available, then no further board specific code should
993 When using a watchdog circuitry external to the used
994 SoC, then define this variable and provide board
995 specific code for the "hw_watchdog_reset" function.
997 CONFIG_AT91_HW_WDT_TIMEOUT
998 specify the timeout in seconds. default 2 seconds.
1001 CONFIG_VERSION_VARIABLE
1002 If this variable is defined, an environment variable
1003 named "ver" is created by U-Boot showing the U-Boot
1004 version as printed by the "version" command.
1005 Any change to this variable will be reverted at the
1010 When CONFIG_CMD_DATE is selected, the type of the RTC
1011 has to be selected, too. Define exactly one of the
1014 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
1015 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
1016 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC
1017 CONFIG_RTC_MC146818 - use MC146818 RTC
1018 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
1019 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
1020 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
1021 CONFIG_RTC_DS1339 - use Maxim, Inc. DS1339 RTC
1022 CONFIG_RTC_DS164x - use Dallas DS164x RTC
1023 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
1024 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
1025 CONFIG_SYS_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
1026 CONFIG_SYS_RV3029_TCR - enable trickle charger on
1029 Note that if the RTC uses I2C, then the I2C interface
1030 must also be configured. See I2C Support, below.
1033 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
1035 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
1036 chip-ngpio pairs that tell the PCA953X driver the number of
1037 pins supported by a particular chip.
1039 Note that if the GPIO device uses I2C, then the I2C interface
1040 must also be configured. See I2C Support, below.
1043 When CONFIG_IO_TRACE is selected, U-Boot intercepts all I/O
1044 accesses and can checksum them or write a list of them out
1045 to memory. See the 'iotrace' command for details. This is
1046 useful for testing device drivers since it can confirm that
1047 the driver behaves the same way before and after a code
1048 change. Currently this is supported on sandbox and arm. To
1049 add support for your architecture, add '#include <iotrace.h>'
1050 to the bottom of arch/<arch>/include/asm/io.h and test.
1052 Example output from the 'iotrace stats' command is below.
1053 Note that if the trace buffer is exhausted, the checksum will
1054 still continue to operate.
1057 Start: 10000000 (buffer start address)
1058 Size: 00010000 (buffer size)
1059 Offset: 00000120 (current buffer offset)
1060 Output: 10000120 (start + offset)
1061 Count: 00000018 (number of trace records)
1062 CRC32: 9526fb66 (CRC32 of all trace records)
1064 - Timestamp Support:
1066 When CONFIG_TIMESTAMP is selected, the timestamp
1067 (date and time) of an image is printed by image
1068 commands like bootm or iminfo. This option is
1069 automatically enabled when you select CONFIG_CMD_DATE .
1071 - Partition Labels (disklabels) Supported:
1072 Zero or more of the following:
1073 CONFIG_MAC_PARTITION Apple's MacOS partition table.
1074 CONFIG_DOS_PARTITION MS Dos partition table, traditional on the
1075 Intel architecture, USB sticks, etc.
1076 CONFIG_ISO_PARTITION ISO partition table, used on CDROM etc.
1077 CONFIG_EFI_PARTITION GPT partition table, common when EFI is the
1078 bootloader. Note 2TB partition limit; see
1080 CONFIG_MTD_PARTITIONS Memory Technology Device partition table.
1082 If IDE or SCSI support is enabled (CONFIG_IDE or
1083 CONFIG_SCSI) you must configure support for at
1084 least one non-MTD partition type as well.
1087 CONFIG_IDE_RESET_ROUTINE - this is defined in several
1088 board configurations files but used nowhere!
1090 CONFIG_IDE_RESET - is this is defined, IDE Reset will
1091 be performed by calling the function
1092 ide_set_reset(int reset)
1093 which has to be defined in a board specific file
1098 Set this to enable ATAPI support.
1103 Set this to enable support for disks larger than 137GB
1104 Also look at CONFIG_SYS_64BIT_LBA.
1105 Whithout these , LBA48 support uses 32bit variables and will 'only'
1106 support disks up to 2.1TB.
1108 CONFIG_SYS_64BIT_LBA:
1109 When enabled, makes the IDE subsystem use 64bit sector addresses.
1113 At the moment only there is only support for the
1114 SYM53C8XX SCSI controller; define
1115 CONFIG_SCSI_SYM53C8XX to enable it.
1117 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
1118 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
1119 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
1120 maximum numbers of LUNs, SCSI ID's and target
1122 CONFIG_SYS_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
1124 The environment variable 'scsidevs' is set to the number of
1125 SCSI devices found during the last scan.
1127 - NETWORK Support (PCI):
1129 Support for Intel 8254x/8257x gigabit chips.
1132 Utility code for direct access to the SPI bus on Intel 8257x.
1133 This does not do anything useful unless you set at least one
1134 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
1136 CONFIG_E1000_SPI_GENERIC
1137 Allow generic access to the SPI bus on the Intel 8257x, for
1138 example with the "sspi" command.
1141 Management command for E1000 devices. When used on devices
1142 with SPI support you can reprogram the EEPROM from U-Boot.
1145 Support for Intel 82557/82559/82559ER chips.
1146 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
1147 write routine for first time initialisation.
1150 Support for Digital 2114x chips.
1151 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
1152 modem chip initialisation (KS8761/QS6611).
1155 Support for National dp83815 chips.
1158 Support for National dp8382[01] gigabit chips.
1160 - NETWORK Support (other):
1162 CONFIG_DRIVER_AT91EMAC
1163 Support for AT91RM9200 EMAC.
1166 Define this to use reduced MII inteface
1168 CONFIG_DRIVER_AT91EMAC_QUIET
1169 If this defined, the driver is quiet.
1170 The driver doen't show link status messages.
1172 CONFIG_CALXEDA_XGMAC
1173 Support for the Calxeda XGMAC device
1176 Support for SMSC's LAN91C96 chips.
1178 CONFIG_LAN91C96_USE_32_BIT
1179 Define this to enable 32 bit addressing
1182 Support for SMSC's LAN91C111 chip
1184 CONFIG_SMC91111_BASE
1185 Define this to hold the physical address
1186 of the device (I/O space)
1188 CONFIG_SMC_USE_32_BIT
1189 Define this if data bus is 32 bits
1191 CONFIG_SMC_USE_IOFUNCS
1192 Define this to use i/o functions instead of macros
1193 (some hardware wont work with macros)
1195 CONFIG_DRIVER_TI_EMAC
1196 Support for davinci emac
1198 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
1199 Define this if you have more then 3 PHYs.
1202 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
1204 CONFIG_FTGMAC100_EGIGA
1205 Define this to use GE link update with gigabit PHY.
1206 Define this if FTGMAC100 is connected to gigabit PHY.
1207 If your system has 10/100 PHY only, it might not occur
1208 wrong behavior. Because PHY usually return timeout or
1209 useless data when polling gigabit status and gigabit
1210 control registers. This behavior won't affect the
1211 correctnessof 10/100 link speed update.
1214 Support for SMSC's LAN911x and LAN921x chips
1217 Define this to hold the physical address
1218 of the device (I/O space)
1220 CONFIG_SMC911X_32_BIT
1221 Define this if data bus is 32 bits
1223 CONFIG_SMC911X_16_BIT
1224 Define this if data bus is 16 bits. If your processor
1225 automatically converts one 32 bit word to two 16 bit
1226 words you may also try CONFIG_SMC911X_32_BIT.
1229 Support for Renesas on-chip Ethernet controller
1231 CONFIG_SH_ETHER_USE_PORT
1232 Define the number of ports to be used
1234 CONFIG_SH_ETHER_PHY_ADDR
1235 Define the ETH PHY's address
1237 CONFIG_SH_ETHER_CACHE_WRITEBACK
1238 If this option is set, the driver enables cache flush.
1242 Support for PWM module on the imx6.
1246 Support TPM devices.
1248 CONFIG_TPM_TIS_INFINEON
1249 Support for Infineon i2c bus TPM devices. Only one device
1250 per system is supported at this time.
1252 CONFIG_TPM_TIS_I2C_BURST_LIMITATION
1253 Define the burst count bytes upper limit
1256 Support for STMicroelectronics TPM devices. Requires DM_TPM support.
1258 CONFIG_TPM_ST33ZP24_I2C
1259 Support for STMicroelectronics ST33ZP24 I2C devices.
1260 Requires TPM_ST33ZP24 and I2C.
1262 CONFIG_TPM_ST33ZP24_SPI
1263 Support for STMicroelectronics ST33ZP24 SPI devices.
1264 Requires TPM_ST33ZP24 and SPI.
1266 CONFIG_TPM_ATMEL_TWI
1267 Support for Atmel TWI TPM device. Requires I2C support.
1270 Support for generic parallel port TPM devices. Only one device
1271 per system is supported at this time.
1273 CONFIG_TPM_TIS_BASE_ADDRESS
1274 Base address where the generic TPM device is mapped
1275 to. Contemporary x86 systems usually map it at
1279 Add tpm monitor functions.
1280 Requires CONFIG_TPM. If CONFIG_TPM_AUTH_SESSIONS is set, also
1281 provides monitor access to authorized functions.
1284 Define this to enable the TPM support library which provides
1285 functional interfaces to some TPM commands.
1286 Requires support for a TPM device.
1288 CONFIG_TPM_AUTH_SESSIONS
1289 Define this to enable authorized functions in the TPM library.
1290 Requires CONFIG_TPM and CONFIG_SHA1.
1293 At the moment only the UHCI host controller is
1294 supported (PIP405, MIP405, MPC5200); define
1295 CONFIG_USB_UHCI to enable it.
1296 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
1297 and define CONFIG_USB_STORAGE to enable the USB
1300 Supported are USB Keyboards and USB Floppy drives
1302 MPC5200 USB requires additional defines:
1304 for 528 MHz Clock: 0x0001bbbb
1308 for differential drivers: 0x00001000
1309 for single ended drivers: 0x00005000
1310 for differential drivers on PSC3: 0x00000100
1311 for single ended drivers on PSC3: 0x00004100
1312 CONFIG_SYS_USB_EVENT_POLL
1313 May be defined to allow interrupt polling
1314 instead of using asynchronous interrupts
1316 CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
1317 txfilltuning field in the EHCI controller on reset.
1319 CONFIG_USB_DWC2_REG_ADDR the physical CPU address of the DWC2
1320 HW module registers.
1323 Define the below if you wish to use the USB console.
1324 Once firmware is rebuilt from a serial console issue the
1325 command "setenv stdin usbtty; setenv stdout usbtty" and
1326 attach your USB cable. The Unix command "dmesg" should print
1327 it has found a new device. The environment variable usbtty
1328 can be set to gserial or cdc_acm to enable your device to
1329 appear to a USB host as a Linux gserial device or a
1330 Common Device Class Abstract Control Model serial device.
1331 If you select usbtty = gserial you should be able to enumerate
1333 # modprobe usbserial vendor=0xVendorID product=0xProductID
1334 else if using cdc_acm, simply setting the environment
1335 variable usbtty to be cdc_acm should suffice. The following
1336 might be defined in YourBoardName.h
1339 Define this to build a UDC device
1342 Define this to have a tty type of device available to
1343 talk to the UDC device
1346 Define this to enable the high speed support for usb
1347 device and usbtty. If this feature is enabled, a routine
1348 int is_usbd_high_speed(void)
1349 also needs to be defined by the driver to dynamically poll
1350 whether the enumeration has succeded at high speed or full
1353 CONFIG_SYS_CONSOLE_IS_IN_ENV
1354 Define this if you want stdin, stdout &/or stderr to
1358 CONFIG_SYS_USB_EXTC_CLK 0xBLAH
1359 Derive USB clock from external clock "blah"
1360 - CONFIG_SYS_USB_EXTC_CLK 0x02
1362 If you have a USB-IF assigned VendorID then you may wish to
1363 define your own vendor specific values either in BoardName.h
1364 or directly in usbd_vendor_info.h. If you don't define
1365 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
1366 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
1367 should pretend to be a Linux device to it's target host.
1369 CONFIG_USBD_MANUFACTURER
1370 Define this string as the name of your company for
1371 - CONFIG_USBD_MANUFACTURER "my company"
1373 CONFIG_USBD_PRODUCT_NAME
1374 Define this string as the name of your product
1375 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
1377 CONFIG_USBD_VENDORID
1378 Define this as your assigned Vendor ID from the USB
1379 Implementors Forum. This *must* be a genuine Vendor ID
1380 to avoid polluting the USB namespace.
1381 - CONFIG_USBD_VENDORID 0xFFFF
1383 CONFIG_USBD_PRODUCTID
1384 Define this as the unique Product ID
1386 - CONFIG_USBD_PRODUCTID 0xFFFF
1388 - ULPI Layer Support:
1389 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
1390 the generic ULPI layer. The generic layer accesses the ULPI PHY
1391 via the platform viewport, so you need both the genric layer and
1392 the viewport enabled. Currently only Chipidea/ARC based
1393 viewport is supported.
1394 To enable the ULPI layer support, define CONFIG_USB_ULPI and
1395 CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
1396 If your ULPI phy needs a different reference clock than the
1397 standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to
1398 the appropriate value in Hz.
1401 The MMC controller on the Intel PXA is supported. To
1402 enable this define CONFIG_MMC. The MMC can be
1403 accessed from the boot prompt by mapping the device
1404 to physical memory similar to flash. Command line is
1405 enabled with CONFIG_CMD_MMC. The MMC driver also works with
1406 the FAT fs. This is enabled with CONFIG_CMD_FAT.
1409 Support for Renesas on-chip MMCIF controller
1411 CONFIG_SH_MMCIF_ADDR
1412 Define the base address of MMCIF registers
1415 Define the clock frequency for MMCIF
1417 CONFIG_SUPPORT_EMMC_BOOT
1418 Enable some additional features of the eMMC boot partitions.
1420 CONFIG_SUPPORT_EMMC_RPMB
1421 Enable the commands for reading, writing and programming the
1422 key for the Replay Protection Memory Block partition in eMMC.
1424 - USB Device Firmware Update (DFU) class support:
1425 CONFIG_USB_FUNCTION_DFU
1426 This enables the USB portion of the DFU USB class
1429 This enables the command "dfu" which is used to have
1430 U-Boot create a DFU class device via USB. This command
1431 requires that the "dfu_alt_info" environment variable be
1432 set and define the alt settings to expose to the host.
1435 This enables support for exposing (e)MMC devices via DFU.
1438 This enables support for exposing NAND devices via DFU.
1441 This enables support for exposing RAM via DFU.
1442 Note: DFU spec refer to non-volatile memory usage, but
1443 allow usages beyond the scope of spec - here RAM usage,
1444 one that would help mostly the developer.
1446 CONFIG_SYS_DFU_DATA_BUF_SIZE
1447 Dfu transfer uses a buffer before writing data to the
1448 raw storage device. Make the size (in bytes) of this buffer
1449 configurable. The size of this buffer is also configurable
1450 through the "dfu_bufsiz" environment variable.
1452 CONFIG_SYS_DFU_MAX_FILE_SIZE
1453 When updating files rather than the raw storage device,
1454 we use a static buffer to copy the file into and then write
1455 the buffer once we've been given the whole file. Define
1456 this to the maximum filesize (in bytes) for the buffer.
1457 Default is 4 MiB if undefined.
1459 DFU_DEFAULT_POLL_TIMEOUT
1460 Poll timeout [ms], is the timeout a device can send to the
1461 host. The host must wait for this timeout before sending
1462 a subsequent DFU_GET_STATUS request to the device.
1464 DFU_MANIFEST_POLL_TIMEOUT
1465 Poll timeout [ms], which the device sends to the host when
1466 entering dfuMANIFEST state. Host waits this timeout, before
1467 sending again an USB request to the device.
1469 - USB Device Android Fastboot support:
1470 CONFIG_USB_FUNCTION_FASTBOOT
1471 This enables the USB part of the fastboot gadget
1474 This enables the command "fastboot" which enables the Android
1475 fastboot mode for the platform's USB device. Fastboot is a USB
1476 protocol for downloading images, flashing and device control
1477 used on Android devices.
1478 See doc/README.android-fastboot for more information.
1480 CONFIG_ANDROID_BOOT_IMAGE
1481 This enables support for booting images which use the Android
1482 image format header.
1484 CONFIG_FASTBOOT_BUF_ADDR
1485 The fastboot protocol requires a large memory buffer for
1486 downloads. Define this to the starting RAM address to use for
1489 CONFIG_FASTBOOT_BUF_SIZE
1490 The fastboot protocol requires a large memory buffer for
1491 downloads. This buffer should be as large as possible for a
1492 platform. Define this to the size available RAM for fastboot.
1494 CONFIG_FASTBOOT_FLASH
1495 The fastboot protocol includes a "flash" command for writing
1496 the downloaded image to a non-volatile storage device. Define
1497 this to enable the "fastboot flash" command.
1499 CONFIG_FASTBOOT_FLASH_MMC_DEV
1500 The fastboot "flash" command requires additional information
1501 regarding the non-volatile storage device. Define this to
1502 the eMMC device that fastboot should use to store the image.
1504 CONFIG_FASTBOOT_GPT_NAME
1505 The fastboot "flash" command supports writing the downloaded
1506 image to the Protective MBR and the Primary GUID Partition
1507 Table. (Additionally, this downloaded image is post-processed
1508 to generate and write the Backup GUID Partition Table.)
1509 This occurs when the specified "partition name" on the
1510 "fastboot flash" command line matches this value.
1511 The default is "gpt" if undefined.
1513 CONFIG_FASTBOOT_MBR_NAME
1514 The fastboot "flash" command supports writing the downloaded
1516 This occurs when the "partition name" specified on the
1517 "fastboot flash" command line matches this value.
1518 If not defined the default value "mbr" is used.
1520 - Journaling Flash filesystem support:
1522 Define these for a default partition on a NAND device
1524 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1525 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1526 Define these for a default partition on a NOR device
1528 - FAT(File Allocation Table) filesystem write function support:
1531 Define this to enable support for saving memory data as a
1532 file in FAT formatted partition.
1534 This will also enable the command "fatwrite" enabling the
1535 user to write files to FAT.
1537 - FAT(File Allocation Table) filesystem cluster size:
1538 CONFIG_FS_FAT_MAX_CLUSTSIZE
1540 Define the max cluster size for fat operations else
1541 a default value of 65536 will be defined.
1544 See Kconfig help for available keyboard drivers.
1548 Define this to enable a custom keyboard support.
1549 This simply calls drv_keyboard_init() which must be
1550 defined in your board-specific files. This option is deprecated
1551 and is only used by novena. For new boards, use driver model
1556 Enable the Freescale DIU video driver. Reference boards for
1557 SOCs that have a DIU should define this macro to enable DIU
1558 support, and should also define these other macros:
1563 CONFIG_VIDEO_SW_CURSOR
1564 CONFIG_VGA_AS_SINGLE_DEVICE
1566 CONFIG_VIDEO_BMP_LOGO
1568 The DIU driver will look for the 'video-mode' environment
1569 variable, and if defined, enable the DIU as a console during
1570 boot. See the documentation file doc/README.video for a
1571 description of this variable.
1573 - LCD Support: CONFIG_LCD
1575 Define this to enable LCD support (for output to LCD
1576 display); also select one of the supported displays
1577 by defining one of these:
1581 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1583 CONFIG_NEC_NL6448AC33:
1585 NEC NL6448AC33-18. Active, color, single scan.
1587 CONFIG_NEC_NL6448BC20
1589 NEC NL6448BC20-08. 6.5", 640x480.
1590 Active, color, single scan.
1592 CONFIG_NEC_NL6448BC33_54
1594 NEC NL6448BC33-54. 10.4", 640x480.
1595 Active, color, single scan.
1599 Sharp 320x240. Active, color, single scan.
1600 It isn't 16x9, and I am not sure what it is.
1602 CONFIG_SHARP_LQ64D341
1604 Sharp LQ64D341 display, 640x480.
1605 Active, color, single scan.
1609 HLD1045 display, 640x480.
1610 Active, color, single scan.
1614 Optrex CBL50840-2 NF-FW 99 22 M5
1616 Hitachi LMG6912RPFC-00T
1620 320x240. Black & white.
1622 CONFIG_LCD_ALIGNMENT
1624 Normally the LCD is page-aligned (typically 4KB). If this is
1625 defined then the LCD will be aligned to this value instead.
1626 For ARM it is sometimes useful to use MMU_SECTION_SIZE
1627 here, since it is cheaper to change data cache settings on
1628 a per-section basis.
1633 Sometimes, for example if the display is mounted in portrait
1634 mode or even if it's mounted landscape but rotated by 180degree,
1635 we need to rotate our content of the display relative to the
1636 framebuffer, so that user can read the messages which are
1638 Once CONFIG_LCD_ROTATION is defined, the lcd_console will be
1639 initialized with a given rotation from "vl_rot" out of
1640 "vidinfo_t" which is provided by the board specific code.
1641 The value for vl_rot is coded as following (matching to
1642 fbcon=rotate:<n> linux-kernel commandline):
1643 0 = no rotation respectively 0 degree
1644 1 = 90 degree rotation
1645 2 = 180 degree rotation
1646 3 = 270 degree rotation
1648 If CONFIG_LCD_ROTATION is not defined, the console will be
1649 initialized with 0degree rotation.
1653 Support drawing of RLE8-compressed bitmaps on the LCD.
1657 Enables an 'i2c edid' command which can read EDID
1658 information over I2C from an attached LCD display.
1660 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1662 If this option is set, the environment is checked for
1663 a variable "splashimage". If found, the usual display
1664 of logo, copyright and system information on the LCD
1665 is suppressed and the BMP image at the address
1666 specified in "splashimage" is loaded instead. The
1667 console is redirected to the "nulldev", too. This
1668 allows for a "silent" boot where a splash screen is
1669 loaded very quickly after power-on.
1671 CONFIG_SPLASHIMAGE_GUARD
1673 If this option is set, then U-Boot will prevent the environment
1674 variable "splashimage" from being set to a problematic address
1675 (see doc/README.displaying-bmps).
1676 This option is useful for targets where, due to alignment
1677 restrictions, an improperly aligned BMP image will cause a data
1678 abort. If you think you will not have problems with unaligned
1679 accesses (for example because your toolchain prevents them)
1680 there is no need to set this option.
1682 CONFIG_SPLASH_SCREEN_ALIGN
1684 If this option is set the splash image can be freely positioned
1685 on the screen. Environment variable "splashpos" specifies the
1686 position as "x,y". If a positive number is given it is used as
1687 number of pixel from left/top. If a negative number is given it
1688 is used as number of pixel from right/bottom. You can also
1689 specify 'm' for centering the image.
1692 setenv splashpos m,m
1693 => image at center of screen
1695 setenv splashpos 30,20
1696 => image at x = 30 and y = 20
1698 setenv splashpos -10,m
1699 => vertically centered image
1700 at x = dspWidth - bmpWidth - 9
1702 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1704 If this option is set, additionally to standard BMP
1705 images, gzipped BMP images can be displayed via the
1706 splashscreen support or the bmp command.
1708 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1710 If this option is set, 8-bit RLE compressed BMP images
1711 can be displayed via the splashscreen support or the
1714 - Compression support:
1717 Enabled by default to support gzip compressed images.
1721 If this option is set, support for bzip2 compressed
1722 images is included. If not, only uncompressed and gzip
1723 compressed images are supported.
1725 NOTE: the bzip2 algorithm requires a lot of RAM, so
1726 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1731 If this option is set, support for lzma compressed
1734 Note: The LZMA algorithm adds between 2 and 4KB of code and it
1735 requires an amount of dynamic memory that is given by the
1738 (1846 + 768 << (lc + lp)) * sizeof(uint16)
1740 Where lc and lp stand for, respectively, Literal context bits
1741 and Literal pos bits.
1743 This value is upper-bounded by 14MB in the worst case. Anyway,
1744 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
1745 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
1746 a very small buffer.
1748 Use the lzmainfo tool to determinate the lc and lp values and
1749 then calculate the amount of needed dynamic memory (ensuring
1750 the appropriate CONFIG_SYS_MALLOC_LEN value).
1754 If this option is set, support for LZO compressed images
1760 The address of PHY on MII bus.
1762 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1764 The clock frequency of the MII bus
1768 If this option is set, support for speed/duplex
1769 detection of gigabit PHY is included.
1771 CONFIG_PHY_RESET_DELAY
1773 Some PHY like Intel LXT971A need extra delay after
1774 reset before any MII register access is possible.
1775 For such PHY, set this option to the usec delay
1776 required. (minimum 300usec for LXT971A)
1778 CONFIG_PHY_CMD_DELAY (ppc4xx)
1780 Some PHY like Intel LXT971A need extra delay after
1781 command issued before MII status register can be read
1786 Define a default value for the IP address to use for
1787 the default Ethernet interface, in case this is not
1788 determined through e.g. bootp.
1789 (Environment variable "ipaddr")
1791 - Server IP address:
1794 Defines a default value for the IP address of a TFTP
1795 server to contact when using the "tftboot" command.
1796 (Environment variable "serverip")
1798 CONFIG_KEEP_SERVERADDR
1800 Keeps the server's MAC address, in the env 'serveraddr'
1801 for passing to bootargs (like Linux's netconsole option)
1803 - Gateway IP address:
1806 Defines a default value for the IP address of the
1807 default router where packets to other networks are
1809 (Environment variable "gatewayip")
1814 Defines a default value for the subnet mask (or
1815 routing prefix) which is used to determine if an IP
1816 address belongs to the local subnet or needs to be
1817 forwarded through a router.
1818 (Environment variable "netmask")
1820 - Multicast TFTP Mode:
1823 Defines whether you want to support multicast TFTP as per
1824 rfc-2090; for example to work with atftp. Lets lots of targets
1825 tftp down the same boot image concurrently. Note: the Ethernet
1826 driver in use must provide a function: mcast() to join/leave a
1829 - BOOTP Recovery Mode:
1830 CONFIG_BOOTP_RANDOM_DELAY
1832 If you have many targets in a network that try to
1833 boot using BOOTP, you may want to avoid that all
1834 systems send out BOOTP requests at precisely the same
1835 moment (which would happen for instance at recovery
1836 from a power failure, when all systems will try to
1837 boot, thus flooding the BOOTP server. Defining
1838 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1839 inserted before sending out BOOTP requests. The
1840 following delays are inserted then:
1842 1st BOOTP request: delay 0 ... 1 sec
1843 2nd BOOTP request: delay 0 ... 2 sec
1844 3rd BOOTP request: delay 0 ... 4 sec
1846 BOOTP requests: delay 0 ... 8 sec
1848 CONFIG_BOOTP_ID_CACHE_SIZE
1850 BOOTP packets are uniquely identified using a 32-bit ID. The
1851 server will copy the ID from client requests to responses and
1852 U-Boot will use this to determine if it is the destination of
1853 an incoming response. Some servers will check that addresses
1854 aren't in use before handing them out (usually using an ARP
1855 ping) and therefore take up to a few hundred milliseconds to
1856 respond. Network congestion may also influence the time it
1857 takes for a response to make it back to the client. If that
1858 time is too long, U-Boot will retransmit requests. In order
1859 to allow earlier responses to still be accepted after these
1860 retransmissions, U-Boot's BOOTP client keeps a small cache of
1861 IDs. The CONFIG_BOOTP_ID_CACHE_SIZE controls the size of this
1862 cache. The default is to keep IDs for up to four outstanding
1863 requests. Increasing this will allow U-Boot to accept offers
1864 from a BOOTP client in networks with unusually high latency.
1866 - DHCP Advanced Options:
1867 You can fine tune the DHCP functionality by defining
1868 CONFIG_BOOTP_* symbols:
1870 CONFIG_BOOTP_SUBNETMASK
1871 CONFIG_BOOTP_GATEWAY
1872 CONFIG_BOOTP_HOSTNAME
1873 CONFIG_BOOTP_NISDOMAIN
1874 CONFIG_BOOTP_BOOTPATH
1875 CONFIG_BOOTP_BOOTFILESIZE
1878 CONFIG_BOOTP_SEND_HOSTNAME
1879 CONFIG_BOOTP_NTPSERVER
1880 CONFIG_BOOTP_TIMEOFFSET
1881 CONFIG_BOOTP_VENDOREX
1882 CONFIG_BOOTP_MAY_FAIL
1884 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1885 environment variable, not the BOOTP server.
1887 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
1888 after the configured retry count, the call will fail
1889 instead of starting over. This can be used to fail over
1890 to Link-local IP address configuration if the DHCP server
1893 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1894 serverip from a DHCP server, it is possible that more
1895 than one DNS serverip is offered to the client.
1896 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1897 serverip will be stored in the additional environment
1898 variable "dnsip2". The first DNS serverip is always
1899 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1902 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1903 to do a dynamic update of a DNS server. To do this, they
1904 need the hostname of the DHCP requester.
1905 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1906 of the "hostname" environment variable is passed as
1907 option 12 to the DHCP server.
1909 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1911 A 32bit value in microseconds for a delay between
1912 receiving a "DHCP Offer" and sending the "DHCP Request".
1913 This fixes a problem with certain DHCP servers that don't
1914 respond 100% of the time to a "DHCP request". E.g. On an
1915 AT91RM9200 processor running at 180MHz, this delay needed
1916 to be *at least* 15,000 usec before a Windows Server 2003
1917 DHCP server would reply 100% of the time. I recommend at
1918 least 50,000 usec to be safe. The alternative is to hope
1919 that one of the retries will be successful but note that
1920 the DHCP timeout and retry process takes a longer than
1923 - Link-local IP address negotiation:
1924 Negotiate with other link-local clients on the local network
1925 for an address that doesn't require explicit configuration.
1926 This is especially useful if a DHCP server cannot be guaranteed
1927 to exist in all environments that the device must operate.
1929 See doc/README.link-local for more information.
1932 CONFIG_CDP_DEVICE_ID
1934 The device id used in CDP trigger frames.
1936 CONFIG_CDP_DEVICE_ID_PREFIX
1938 A two character string which is prefixed to the MAC address
1943 A printf format string which contains the ascii name of
1944 the port. Normally is set to "eth%d" which sets
1945 eth0 for the first Ethernet, eth1 for the second etc.
1947 CONFIG_CDP_CAPABILITIES
1949 A 32bit integer which indicates the device capabilities;
1950 0x00000010 for a normal host which does not forwards.
1954 An ascii string containing the version of the software.
1958 An ascii string containing the name of the platform.
1962 A 32bit integer sent on the trigger.
1964 CONFIG_CDP_POWER_CONSUMPTION
1966 A 16bit integer containing the power consumption of the
1967 device in .1 of milliwatts.
1969 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1971 A byte containing the id of the VLAN.
1973 - Status LED: CONFIG_LED_STATUS
1975 Several configurations allow to display the current
1976 status using a LED. For instance, the LED will blink
1977 fast while running U-Boot code, stop blinking as
1978 soon as a reply to a BOOTP request was received, and
1979 start blinking slow once the Linux kernel is running
1980 (supported by a status LED driver in the Linux
1981 kernel). Defining CONFIG_LED_STATUS enables this
1986 CONFIG_LED_STATUS_GPIO
1987 The status LED can be connected to a GPIO pin.
1988 In such cases, the gpio_led driver can be used as a
1989 status LED backend implementation. Define CONFIG_LED_STATUS_GPIO
1990 to include the gpio_led driver in the U-Boot binary.
1992 CONFIG_GPIO_LED_INVERTED_TABLE
1993 Some GPIO connected LEDs may have inverted polarity in which
1994 case the GPIO high value corresponds to LED off state and
1995 GPIO low value corresponds to LED on state.
1996 In such cases CONFIG_GPIO_LED_INVERTED_TABLE may be defined
1997 with a list of GPIO LEDs that have inverted polarity.
1999 - CAN Support: CONFIG_CAN_DRIVER
2001 Defining CONFIG_CAN_DRIVER enables CAN driver support
2002 on those systems that support this (optional)
2003 feature, like the TQM8xxL modules.
2005 - I2C Support: CONFIG_SYS_I2C
2007 This enable the NEW i2c subsystem, and will allow you to use
2008 i2c commands at the u-boot command line (as long as you set
2009 CONFIG_CMD_I2C in CONFIG_COMMANDS) and communicate with i2c
2010 based realtime clock chips or other i2c devices. See
2011 common/cmd_i2c.c for a description of the command line
2014 ported i2c driver to the new framework:
2015 - drivers/i2c/soft_i2c.c:
2016 - activate first bus with CONFIG_SYS_I2C_SOFT define
2017 CONFIG_SYS_I2C_SOFT_SPEED and CONFIG_SYS_I2C_SOFT_SLAVE
2018 for defining speed and slave address
2019 - activate second bus with I2C_SOFT_DECLARATIONS2 define
2020 CONFIG_SYS_I2C_SOFT_SPEED_2 and CONFIG_SYS_I2C_SOFT_SLAVE_2
2021 for defining speed and slave address
2022 - activate third bus with I2C_SOFT_DECLARATIONS3 define
2023 CONFIG_SYS_I2C_SOFT_SPEED_3 and CONFIG_SYS_I2C_SOFT_SLAVE_3
2024 for defining speed and slave address
2025 - activate fourth bus with I2C_SOFT_DECLARATIONS4 define
2026 CONFIG_SYS_I2C_SOFT_SPEED_4 and CONFIG_SYS_I2C_SOFT_SLAVE_4
2027 for defining speed and slave address
2029 - drivers/i2c/fsl_i2c.c:
2030 - activate i2c driver with CONFIG_SYS_I2C_FSL
2031 define CONFIG_SYS_FSL_I2C_OFFSET for setting the register
2032 offset CONFIG_SYS_FSL_I2C_SPEED for the i2c speed and
2033 CONFIG_SYS_FSL_I2C_SLAVE for the slave addr of the first
2035 - If your board supports a second fsl i2c bus, define
2036 CONFIG_SYS_FSL_I2C2_OFFSET for the register offset
2037 CONFIG_SYS_FSL_I2C2_SPEED for the speed and
2038 CONFIG_SYS_FSL_I2C2_SLAVE for the slave address of the
2041 - drivers/i2c/tegra_i2c.c:
2042 - activate this driver with CONFIG_SYS_I2C_TEGRA
2043 - This driver adds 4 i2c buses with a fix speed from
2044 100000 and the slave addr 0!
2046 - drivers/i2c/ppc4xx_i2c.c
2047 - activate this driver with CONFIG_SYS_I2C_PPC4XX
2048 - CONFIG_SYS_I2C_PPC4XX_CH0 activate hardware channel 0
2049 - CONFIG_SYS_I2C_PPC4XX_CH1 activate hardware channel 1
2051 - drivers/i2c/i2c_mxc.c
2052 - activate this driver with CONFIG_SYS_I2C_MXC
2053 - enable bus 1 with CONFIG_SYS_I2C_MXC_I2C1
2054 - enable bus 2 with CONFIG_SYS_I2C_MXC_I2C2
2055 - enable bus 3 with CONFIG_SYS_I2C_MXC_I2C3
2056 - enable bus 4 with CONFIG_SYS_I2C_MXC_I2C4
2057 - define speed for bus 1 with CONFIG_SYS_MXC_I2C1_SPEED
2058 - define slave for bus 1 with CONFIG_SYS_MXC_I2C1_SLAVE
2059 - define speed for bus 2 with CONFIG_SYS_MXC_I2C2_SPEED
2060 - define slave for bus 2 with CONFIG_SYS_MXC_I2C2_SLAVE
2061 - define speed for bus 3 with CONFIG_SYS_MXC_I2C3_SPEED
2062 - define slave for bus 3 with CONFIG_SYS_MXC_I2C3_SLAVE
2063 - define speed for bus 4 with CONFIG_SYS_MXC_I2C4_SPEED
2064 - define slave for bus 4 with CONFIG_SYS_MXC_I2C4_SLAVE
2065 If those defines are not set, default value is 100000
2066 for speed, and 0 for slave.
2068 - drivers/i2c/rcar_i2c.c:
2069 - activate this driver with CONFIG_SYS_I2C_RCAR
2070 - This driver adds 4 i2c buses
2072 - CONFIG_SYS_RCAR_I2C0_BASE for setting the register channel 0
2073 - CONFIG_SYS_RCAR_I2C0_SPEED for for the speed channel 0
2074 - CONFIG_SYS_RCAR_I2C1_BASE for setting the register channel 1
2075 - CONFIG_SYS_RCAR_I2C1_SPEED for for the speed channel 1
2076 - CONFIG_SYS_RCAR_I2C2_BASE for setting the register channel 2
2077 - CONFIG_SYS_RCAR_I2C2_SPEED for for the speed channel 2
2078 - CONFIG_SYS_RCAR_I2C3_BASE for setting the register channel 3
2079 - CONFIG_SYS_RCAR_I2C3_SPEED for for the speed channel 3
2080 - CONFIF_SYS_RCAR_I2C_NUM_CONTROLLERS for number of i2c buses
2082 - drivers/i2c/sh_i2c.c:
2083 - activate this driver with CONFIG_SYS_I2C_SH
2084 - This driver adds from 2 to 5 i2c buses
2086 - CONFIG_SYS_I2C_SH_BASE0 for setting the register channel 0
2087 - CONFIG_SYS_I2C_SH_SPEED0 for for the speed channel 0
2088 - CONFIG_SYS_I2C_SH_BASE1 for setting the register channel 1
2089 - CONFIG_SYS_I2C_SH_SPEED1 for for the speed channel 1
2090 - CONFIG_SYS_I2C_SH_BASE2 for setting the register channel 2
2091 - CONFIG_SYS_I2C_SH_SPEED2 for for the speed channel 2
2092 - CONFIG_SYS_I2C_SH_BASE3 for setting the register channel 3
2093 - CONFIG_SYS_I2C_SH_SPEED3 for for the speed channel 3
2094 - CONFIG_SYS_I2C_SH_BASE4 for setting the register channel 4
2095 - CONFIG_SYS_I2C_SH_SPEED4 for for the speed channel 4
2096 - CONFIG_SYS_I2C_SH_NUM_CONTROLLERS for number of i2c buses
2098 - drivers/i2c/omap24xx_i2c.c
2099 - activate this driver with CONFIG_SYS_I2C_OMAP24XX
2100 - CONFIG_SYS_OMAP24_I2C_SPEED speed channel 0
2101 - CONFIG_SYS_OMAP24_I2C_SLAVE slave addr channel 0
2102 - CONFIG_SYS_OMAP24_I2C_SPEED1 speed channel 1
2103 - CONFIG_SYS_OMAP24_I2C_SLAVE1 slave addr channel 1
2104 - CONFIG_SYS_OMAP24_I2C_SPEED2 speed channel 2
2105 - CONFIG_SYS_OMAP24_I2C_SLAVE2 slave addr channel 2
2106 - CONFIG_SYS_OMAP24_I2C_SPEED3 speed channel 3
2107 - CONFIG_SYS_OMAP24_I2C_SLAVE3 slave addr channel 3
2108 - CONFIG_SYS_OMAP24_I2C_SPEED4 speed channel 4
2109 - CONFIG_SYS_OMAP24_I2C_SLAVE4 slave addr channel 4
2111 - drivers/i2c/zynq_i2c.c
2112 - activate this driver with CONFIG_SYS_I2C_ZYNQ
2113 - set CONFIG_SYS_I2C_ZYNQ_SPEED for speed setting
2114 - set CONFIG_SYS_I2C_ZYNQ_SLAVE for slave addr
2116 - drivers/i2c/s3c24x0_i2c.c:
2117 - activate this driver with CONFIG_SYS_I2C_S3C24X0
2118 - This driver adds i2c buses (11 for Exynos5250, Exynos5420
2119 9 i2c buses for Exynos4 and 1 for S3C24X0 SoCs from Samsung)
2120 with a fix speed from 100000 and the slave addr 0!
2122 - drivers/i2c/ihs_i2c.c
2123 - activate this driver with CONFIG_SYS_I2C_IHS
2124 - CONFIG_SYS_I2C_IHS_CH0 activate hardware channel 0
2125 - CONFIG_SYS_I2C_IHS_SPEED_0 speed channel 0
2126 - CONFIG_SYS_I2C_IHS_SLAVE_0 slave addr channel 0
2127 - CONFIG_SYS_I2C_IHS_CH1 activate hardware channel 1
2128 - CONFIG_SYS_I2C_IHS_SPEED_1 speed channel 1
2129 - CONFIG_SYS_I2C_IHS_SLAVE_1 slave addr channel 1
2130 - CONFIG_SYS_I2C_IHS_CH2 activate hardware channel 2
2131 - CONFIG_SYS_I2C_IHS_SPEED_2 speed channel 2
2132 - CONFIG_SYS_I2C_IHS_SLAVE_2 slave addr channel 2
2133 - CONFIG_SYS_I2C_IHS_CH3 activate hardware channel 3
2134 - CONFIG_SYS_I2C_IHS_SPEED_3 speed channel 3
2135 - CONFIG_SYS_I2C_IHS_SLAVE_3 slave addr channel 3
2136 - activate dual channel with CONFIG_SYS_I2C_IHS_DUAL
2137 - CONFIG_SYS_I2C_IHS_SPEED_0_1 speed channel 0_1
2138 - CONFIG_SYS_I2C_IHS_SLAVE_0_1 slave addr channel 0_1
2139 - CONFIG_SYS_I2C_IHS_SPEED_1_1 speed channel 1_1
2140 - CONFIG_SYS_I2C_IHS_SLAVE_1_1 slave addr channel 1_1
2141 - CONFIG_SYS_I2C_IHS_SPEED_2_1 speed channel 2_1
2142 - CONFIG_SYS_I2C_IHS_SLAVE_2_1 slave addr channel 2_1
2143 - CONFIG_SYS_I2C_IHS_SPEED_3_1 speed channel 3_1
2144 - CONFIG_SYS_I2C_IHS_SLAVE_3_1 slave addr channel 3_1
2148 CONFIG_SYS_NUM_I2C_BUSES
2149 Hold the number of i2c buses you want to use.
2151 CONFIG_SYS_I2C_DIRECT_BUS
2152 define this, if you don't use i2c muxes on your hardware.
2153 if CONFIG_SYS_I2C_MAX_HOPS is not defined or == 0 you can
2156 CONFIG_SYS_I2C_MAX_HOPS
2157 define how many muxes are maximal consecutively connected
2158 on one i2c bus. If you not use i2c muxes, omit this
2161 CONFIG_SYS_I2C_BUSES
2162 hold a list of buses you want to use, only used if
2163 CONFIG_SYS_I2C_DIRECT_BUS is not defined, for example
2164 a board with CONFIG_SYS_I2C_MAX_HOPS = 1 and
2165 CONFIG_SYS_NUM_I2C_BUSES = 9:
2167 CONFIG_SYS_I2C_BUSES {{0, {I2C_NULL_HOP}}, \
2168 {0, {{I2C_MUX_PCA9547, 0x70, 1}}}, \
2169 {0, {{I2C_MUX_PCA9547, 0x70, 2}}}, \
2170 {0, {{I2C_MUX_PCA9547, 0x70, 3}}}, \
2171 {0, {{I2C_MUX_PCA9547, 0x70, 4}}}, \
2172 {0, {{I2C_MUX_PCA9547, 0x70, 5}}}, \
2173 {1, {I2C_NULL_HOP}}, \
2174 {1, {{I2C_MUX_PCA9544, 0x72, 1}}}, \
2175 {1, {{I2C_MUX_PCA9544, 0x72, 2}}}, \
2179 bus 0 on adapter 0 without a mux
2180 bus 1 on adapter 0 with a PCA9547 on address 0x70 port 1
2181 bus 2 on adapter 0 with a PCA9547 on address 0x70 port 2
2182 bus 3 on adapter 0 with a PCA9547 on address 0x70 port 3
2183 bus 4 on adapter 0 with a PCA9547 on address 0x70 port 4
2184 bus 5 on adapter 0 with a PCA9547 on address 0x70 port 5
2185 bus 6 on adapter 1 without a mux
2186 bus 7 on adapter 1 with a PCA9544 on address 0x72 port 1
2187 bus 8 on adapter 1 with a PCA9544 on address 0x72 port 2
2189 If you do not have i2c muxes on your board, omit this define.
2191 - Legacy I2C Support:
2192 If you use the software i2c interface (CONFIG_SYS_I2C_SOFT)
2193 then the following macros need to be defined (examples are
2194 from include/configs/lwmon.h):
2198 (Optional). Any commands necessary to enable the I2C
2199 controller or configure ports.
2201 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
2205 (Only for MPC8260 CPU). The I/O port to use (the code
2206 assumes both bits are on the same port). Valid values
2207 are 0..3 for ports A..D.
2211 The code necessary to make the I2C data line active
2212 (driven). If the data line is open collector, this
2215 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
2219 The code necessary to make the I2C data line tri-stated
2220 (inactive). If the data line is open collector, this
2223 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
2227 Code that returns true if the I2C data line is high,
2230 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
2234 If <bit> is true, sets the I2C data line high. If it
2235 is false, it clears it (low).
2237 eg: #define I2C_SDA(bit) \
2238 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
2239 else immr->im_cpm.cp_pbdat &= ~PB_SDA
2243 If <bit> is true, sets the I2C clock line high. If it
2244 is false, it clears it (low).
2246 eg: #define I2C_SCL(bit) \
2247 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
2248 else immr->im_cpm.cp_pbdat &= ~PB_SCL
2252 This delay is invoked four times per clock cycle so this
2253 controls the rate of data transfer. The data rate thus
2254 is 1 / (I2C_DELAY * 4). Often defined to be something
2257 #define I2C_DELAY udelay(2)
2259 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
2261 If your arch supports the generic GPIO framework (asm/gpio.h),
2262 then you may alternatively define the two GPIOs that are to be
2263 used as SCL / SDA. Any of the previous I2C_xxx macros will
2264 have GPIO-based defaults assigned to them as appropriate.
2266 You should define these to the GPIO value as given directly to
2267 the generic GPIO functions.
2269 CONFIG_SYS_I2C_INIT_BOARD
2271 When a board is reset during an i2c bus transfer
2272 chips might think that the current transfer is still
2273 in progress. On some boards it is possible to access
2274 the i2c SCLK line directly, either by using the
2275 processor pin as a GPIO or by having a second pin
2276 connected to the bus. If this option is defined a
2277 custom i2c_init_board() routine in boards/xxx/board.c
2278 is run early in the boot sequence.
2280 CONFIG_I2C_MULTI_BUS
2282 This option allows the use of multiple I2C buses, each of which
2283 must have a controller. At any point in time, only one bus is
2284 active. To switch to a different bus, use the 'i2c dev' command.
2285 Note that bus numbering is zero-based.
2287 CONFIG_SYS_I2C_NOPROBES
2289 This option specifies a list of I2C devices that will be skipped
2290 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
2291 is set, specify a list of bus-device pairs. Otherwise, specify
2292 a 1D array of device addresses
2295 #undef CONFIG_I2C_MULTI_BUS
2296 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
2298 will skip addresses 0x50 and 0x68 on a board with one I2C bus
2300 #define CONFIG_I2C_MULTI_BUS
2301 #define CONFIG_SYS_I2C_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
2303 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
2305 CONFIG_SYS_SPD_BUS_NUM
2307 If defined, then this indicates the I2C bus number for DDR SPD.
2308 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
2310 CONFIG_SYS_RTC_BUS_NUM
2312 If defined, then this indicates the I2C bus number for the RTC.
2313 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
2315 CONFIG_SOFT_I2C_READ_REPEATED_START
2317 defining this will force the i2c_read() function in
2318 the soft_i2c driver to perform an I2C repeated start
2319 between writing the address pointer and reading the
2320 data. If this define is omitted the default behaviour
2321 of doing a stop-start sequence will be used. Most I2C
2322 devices can use either method, but some require one or
2325 - SPI Support: CONFIG_SPI
2327 Enables SPI driver (so far only tested with
2328 SPI EEPROM, also an instance works with Crystal A/D and
2329 D/As on the SACSng board)
2333 Enables the driver for SPI controller on SuperH. Currently
2334 only SH7757 is supported.
2338 Enables a software (bit-bang) SPI driver rather than
2339 using hardware support. This is a general purpose
2340 driver that only requires three general I/O port pins
2341 (two outputs, one input) to function. If this is
2342 defined, the board configuration must define several
2343 SPI configuration items (port pins to use, etc). For
2344 an example, see include/configs/sacsng.h.
2348 Enables a hardware SPI driver for general-purpose reads
2349 and writes. As with CONFIG_SOFT_SPI, the board configuration
2350 must define a list of chip-select function pointers.
2351 Currently supported on some MPC8xxx processors. For an
2352 example, see include/configs/mpc8349emds.h.
2356 Enables the driver for the SPI controllers on i.MX and MXC
2357 SoCs. Currently i.MX31/35/51 are supported.
2359 CONFIG_SYS_SPI_MXC_WAIT
2360 Timeout for waiting until spi transfer completed.
2361 default: (CONFIG_SYS_HZ/100) /* 10 ms */
2363 - FPGA Support: CONFIG_FPGA
2365 Enables FPGA subsystem.
2367 CONFIG_FPGA_<vendor>
2369 Enables support for specific chip vendors.
2372 CONFIG_FPGA_<family>
2374 Enables support for FPGA family.
2375 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
2379 Specify the number of FPGA devices to support.
2381 CONFIG_SYS_FPGA_PROG_FEEDBACK
2383 Enable printing of hash marks during FPGA configuration.
2385 CONFIG_SYS_FPGA_CHECK_BUSY
2387 Enable checks on FPGA configuration interface busy
2388 status by the configuration function. This option
2389 will require a board or device specific function to
2394 If defined, a function that provides delays in the FPGA
2395 configuration driver.
2397 CONFIG_SYS_FPGA_CHECK_CTRLC
2398 Allow Control-C to interrupt FPGA configuration
2400 CONFIG_SYS_FPGA_CHECK_ERROR
2402 Check for configuration errors during FPGA bitfile
2403 loading. For example, abort during Virtex II
2404 configuration if the INIT_B line goes low (which
2405 indicated a CRC error).
2407 CONFIG_SYS_FPGA_WAIT_INIT
2409 Maximum time to wait for the INIT_B line to de-assert
2410 after PROB_B has been de-asserted during a Virtex II
2411 FPGA configuration sequence. The default time is 500
2414 CONFIG_SYS_FPGA_WAIT_BUSY
2416 Maximum time to wait for BUSY to de-assert during
2417 Virtex II FPGA configuration. The default is 5 ms.
2419 CONFIG_SYS_FPGA_WAIT_CONFIG
2421 Time to wait after FPGA configuration. The default is
2424 - Configuration Management:
2427 Some SoCs need special image types (e.g. U-Boot binary
2428 with a special header) as build targets. By defining
2429 CONFIG_BUILD_TARGET in the SoC / board header, this
2430 special image will be automatically built upon calling
2435 If defined, this string will be added to the U-Boot
2436 version information (U_BOOT_VERSION)
2438 - Vendor Parameter Protection:
2440 U-Boot considers the values of the environment
2441 variables "serial#" (Board Serial Number) and
2442 "ethaddr" (Ethernet Address) to be parameters that
2443 are set once by the board vendor / manufacturer, and
2444 protects these variables from casual modification by
2445 the user. Once set, these variables are read-only,
2446 and write or delete attempts are rejected. You can
2447 change this behaviour:
2449 If CONFIG_ENV_OVERWRITE is #defined in your config
2450 file, the write protection for vendor parameters is
2451 completely disabled. Anybody can change or delete
2454 Alternatively, if you define _both_ an ethaddr in the
2455 default env _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2456 Ethernet address is installed in the environment,
2457 which can be changed exactly ONCE by the user. [The
2458 serial# is unaffected by this, i. e. it remains
2461 The same can be accomplished in a more flexible way
2462 for any variable by configuring the type of access
2463 to allow for those variables in the ".flags" variable
2464 or define CONFIG_ENV_FLAGS_LIST_STATIC.
2469 Define this variable to enable the reservation of
2470 "protected RAM", i. e. RAM which is not overwritten
2471 by U-Boot. Define CONFIG_PRAM to hold the number of
2472 kB you want to reserve for pRAM. You can overwrite
2473 this default value by defining an environment
2474 variable "pram" to the number of kB you want to
2475 reserve. Note that the board info structure will
2476 still show the full amount of RAM. If pRAM is
2477 reserved, a new environment variable "mem" will
2478 automatically be defined to hold the amount of
2479 remaining RAM in a form that can be passed as boot
2480 argument to Linux, for instance like that:
2482 setenv bootargs ... mem=\${mem}
2485 This way you can tell Linux not to use this memory,
2486 either, which results in a memory region that will
2487 not be affected by reboots.
2489 *WARNING* If your board configuration uses automatic
2490 detection of the RAM size, you must make sure that
2491 this memory test is non-destructive. So far, the
2492 following board configurations are known to be
2495 IVMS8, IVML24, SPD8xx, TQM8xxL,
2496 HERMES, IP860, RPXlite, LWMON,
2499 - Access to physical memory region (> 4GB)
2500 Some basic support is provided for operations on memory not
2501 normally accessible to U-Boot - e.g. some architectures
2502 support access to more than 4GB of memory on 32-bit
2503 machines using physical address extension or similar.
2504 Define CONFIG_PHYSMEM to access this basic support, which
2505 currently only supports clearing the memory.
2510 Define this variable to stop the system in case of a
2511 fatal error, so that you have to reset it manually.
2512 This is probably NOT a good idea for an embedded
2513 system where you want the system to reboot
2514 automatically as fast as possible, but it may be
2515 useful during development since you can try to debug
2516 the conditions that lead to the situation.
2518 CONFIG_NET_RETRY_COUNT
2520 This variable defines the number of retries for
2521 network operations like ARP, RARP, TFTP, or BOOTP
2522 before giving up the operation. If not defined, a
2523 default value of 5 is used.
2527 Timeout waiting for an ARP reply in milliseconds.
2531 Timeout in milliseconds used in NFS protocol.
2532 If you encounter "ERROR: Cannot umount" in nfs command,
2533 try longer timeout such as
2534 #define CONFIG_NFS_TIMEOUT 10000UL
2536 - Command Interpreter:
2537 CONFIG_AUTO_COMPLETE
2539 Enable auto completion of commands using TAB.
2541 CONFIG_SYS_PROMPT_HUSH_PS2
2543 This defines the secondary prompt string, which is
2544 printed when the command interpreter needs more input
2545 to complete a command. Usually "> ".
2549 In the current implementation, the local variables
2550 space and global environment variables space are
2551 separated. Local variables are those you define by
2552 simply typing `name=value'. To access a local
2553 variable later on, you have write `$name' or
2554 `${name}'; to execute the contents of a variable
2555 directly type `$name' at the command prompt.
2557 Global environment variables are those you use
2558 setenv/printenv to work with. To run a command stored
2559 in such a variable, you need to use the run command,
2560 and you must not use the '$' sign to access them.
2562 To store commands and special characters in a
2563 variable, please use double quotation marks
2564 surrounding the whole text of the variable, instead
2565 of the backslashes before semicolons and special
2568 - Command Line Editing and History:
2569 CONFIG_CMDLINE_EDITING
2571 Enable editing and History functions for interactive
2572 command line input operations
2574 - Command Line PS1/PS2 support:
2575 CONFIG_CMDLINE_PS_SUPPORT
2577 Enable support for changing the command prompt string
2578 at run-time. Only static string is supported so far.
2579 The string is obtained from environment variables PS1
2582 - Default Environment:
2583 CONFIG_EXTRA_ENV_SETTINGS
2585 Define this to contain any number of null terminated
2586 strings (variable = value pairs) that will be part of
2587 the default environment compiled into the boot image.
2589 For example, place something like this in your
2590 board's config file:
2592 #define CONFIG_EXTRA_ENV_SETTINGS \
2596 Warning: This method is based on knowledge about the
2597 internal format how the environment is stored by the
2598 U-Boot code. This is NOT an official, exported
2599 interface! Although it is unlikely that this format
2600 will change soon, there is no guarantee either.
2601 You better know what you are doing here.
2603 Note: overly (ab)use of the default environment is
2604 discouraged. Make sure to check other ways to preset
2605 the environment like the "source" command or the
2608 CONFIG_ENV_VARS_UBOOT_CONFIG
2610 Define this in order to add variables describing the
2611 U-Boot build configuration to the default environment.
2612 These will be named arch, cpu, board, vendor, and soc.
2614 Enabling this option will cause the following to be defined:
2622 CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG
2624 Define this in order to add variables describing certain
2625 run-time determined information about the hardware to the
2626 environment. These will be named board_name, board_rev.
2628 CONFIG_DELAY_ENVIRONMENT
2630 Normally the environment is loaded when the board is
2631 initialised so that it is available to U-Boot. This inhibits
2632 that so that the environment is not available until
2633 explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL
2634 this is instead controlled by the value of
2635 /config/load-environment.
2637 - DataFlash Support:
2638 CONFIG_HAS_DATAFLASH
2640 Defining this option enables DataFlash features and
2641 allows to read/write in Dataflash via the standard
2644 - Serial Flash support
2647 Defining this option enables SPI flash commands
2648 'sf probe/read/write/erase/update'.
2650 Usage requires an initial 'probe' to define the serial
2651 flash parameters, followed by read/write/erase/update
2654 The following defaults may be provided by the platform
2655 to handle the common case when only a single serial
2656 flash is present on the system.
2658 CONFIG_SF_DEFAULT_BUS Bus identifier
2659 CONFIG_SF_DEFAULT_CS Chip-select
2660 CONFIG_SF_DEFAULT_MODE (see include/spi.h)
2661 CONFIG_SF_DEFAULT_SPEED in Hz
2665 Define this option to include a destructive SPI flash
2668 CONFIG_SF_DUAL_FLASH Dual flash memories
2670 Define this option to use dual flash support where two flash
2671 memories can be connected with a given cs line.
2672 Currently Xilinx Zynq qspi supports these type of connections.
2674 - SystemACE Support:
2677 Adding this option adds support for Xilinx SystemACE
2678 chips attached via some sort of local bus. The address
2679 of the chip must also be defined in the
2680 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
2682 #define CONFIG_SYSTEMACE
2683 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
2685 When SystemACE support is added, the "ace" device type
2686 becomes available to the fat commands, i.e. fatls.
2688 - TFTP Fixed UDP Port:
2691 If this is defined, the environment variable tftpsrcp
2692 is used to supply the TFTP UDP source port value.
2693 If tftpsrcp isn't defined, the normal pseudo-random port
2694 number generator is used.
2696 Also, the environment variable tftpdstp is used to supply
2697 the TFTP UDP destination port value. If tftpdstp isn't
2698 defined, the normal port 69 is used.
2700 The purpose for tftpsrcp is to allow a TFTP server to
2701 blindly start the TFTP transfer using the pre-configured
2702 target IP address and UDP port. This has the effect of
2703 "punching through" the (Windows XP) firewall, allowing
2704 the remainder of the TFTP transfer to proceed normally.
2705 A better solution is to properly configure the firewall,
2706 but sometimes that is not allowed.
2711 Enable the hash verify command (hash -v). This adds to code
2714 Note: There is also a sha1sum command, which should perhaps
2715 be deprecated in favour of 'hash sha1'.
2717 - bootcount support:
2718 CONFIG_BOOTCOUNT_LIMIT
2720 This enables the bootcounter support, see:
2721 http://www.denx.de/wiki/DULG/UBootBootCountLimit
2724 enable special bootcounter support on at91sam9xe based boards.
2726 enable special bootcounter support on da850 based boards.
2727 CONFIG_BOOTCOUNT_RAM
2728 enable support for the bootcounter in RAM
2729 CONFIG_BOOTCOUNT_I2C
2730 enable support for the bootcounter on an i2c (like RTC) device.
2731 CONFIG_SYS_I2C_RTC_ADDR = i2c chip address
2732 CONFIG_SYS_BOOTCOUNT_ADDR = i2c addr which is used for
2734 CONFIG_BOOTCOUNT_ALEN = address len
2736 - Show boot progress:
2737 CONFIG_SHOW_BOOT_PROGRESS
2739 Defining this option allows to add some board-
2740 specific code (calling a user-provided function
2741 "show_boot_progress(int)") that enables you to show
2742 the system's boot progress on some display (for
2743 example, some LED's) on your board. At the moment,
2744 the following checkpoints are implemented:
2747 Legacy uImage format:
2750 1 common/cmd_bootm.c before attempting to boot an image
2751 -1 common/cmd_bootm.c Image header has bad magic number
2752 2 common/cmd_bootm.c Image header has correct magic number
2753 -2 common/cmd_bootm.c Image header has bad checksum
2754 3 common/cmd_bootm.c Image header has correct checksum
2755 -3 common/cmd_bootm.c Image data has bad checksum
2756 4 common/cmd_bootm.c Image data has correct checksum
2757 -4 common/cmd_bootm.c Image is for unsupported architecture
2758 5 common/cmd_bootm.c Architecture check OK
2759 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
2760 6 common/cmd_bootm.c Image Type check OK
2761 -6 common/cmd_bootm.c gunzip uncompression error
2762 -7 common/cmd_bootm.c Unimplemented compression type
2763 7 common/cmd_bootm.c Uncompression OK
2764 8 common/cmd_bootm.c No uncompress/copy overwrite error
2765 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
2767 9 common/image.c Start initial ramdisk verification
2768 -10 common/image.c Ramdisk header has bad magic number
2769 -11 common/image.c Ramdisk header has bad checksum
2770 10 common/image.c Ramdisk header is OK
2771 -12 common/image.c Ramdisk data has bad checksum
2772 11 common/image.c Ramdisk data has correct checksum
2773 12 common/image.c Ramdisk verification complete, start loading
2774 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
2775 13 common/image.c Start multifile image verification
2776 14 common/image.c No initial ramdisk, no multifile, continue.
2778 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
2780 -30 arch/powerpc/lib/board.c Fatal error, hang the system
2781 -31 post/post.c POST test failed, detected by post_output_backlog()
2782 -32 post/post.c POST test failed, detected by post_run_single()
2784 34 common/cmd_doc.c before loading a Image from a DOC device
2785 -35 common/cmd_doc.c Bad usage of "doc" command
2786 35 common/cmd_doc.c correct usage of "doc" command
2787 -36 common/cmd_doc.c No boot device
2788 36 common/cmd_doc.c correct boot device
2789 -37 common/cmd_doc.c Unknown Chip ID on boot device
2790 37 common/cmd_doc.c correct chip ID found, device available
2791 -38 common/cmd_doc.c Read Error on boot device
2792 38 common/cmd_doc.c reading Image header from DOC device OK
2793 -39 common/cmd_doc.c Image header has bad magic number
2794 39 common/cmd_doc.c Image header has correct magic number
2795 -40 common/cmd_doc.c Error reading Image from DOC device
2796 40 common/cmd_doc.c Image header has correct magic number
2797 41 common/cmd_ide.c before loading a Image from a IDE device
2798 -42 common/cmd_ide.c Bad usage of "ide" command
2799 42 common/cmd_ide.c correct usage of "ide" command
2800 -43 common/cmd_ide.c No boot device
2801 43 common/cmd_ide.c boot device found
2802 -44 common/cmd_ide.c Device not available
2803 44 common/cmd_ide.c Device available
2804 -45 common/cmd_ide.c wrong partition selected
2805 45 common/cmd_ide.c partition selected
2806 -46 common/cmd_ide.c Unknown partition table
2807 46 common/cmd_ide.c valid partition table found
2808 -47 common/cmd_ide.c Invalid partition type
2809 47 common/cmd_ide.c correct partition type
2810 -48 common/cmd_ide.c Error reading Image Header on boot device
2811 48 common/cmd_ide.c reading Image Header from IDE device OK
2812 -49 common/cmd_ide.c Image header has bad magic number
2813 49 common/cmd_ide.c Image header has correct magic number
2814 -50 common/cmd_ide.c Image header has bad checksum
2815 50 common/cmd_ide.c Image header has correct checksum
2816 -51 common/cmd_ide.c Error reading Image from IDE device
2817 51 common/cmd_ide.c reading Image from IDE device OK
2818 52 common/cmd_nand.c before loading a Image from a NAND device
2819 -53 common/cmd_nand.c Bad usage of "nand" command
2820 53 common/cmd_nand.c correct usage of "nand" command
2821 -54 common/cmd_nand.c No boot device
2822 54 common/cmd_nand.c boot device found
2823 -55 common/cmd_nand.c Unknown Chip ID on boot device
2824 55 common/cmd_nand.c correct chip ID found, device available
2825 -56 common/cmd_nand.c Error reading Image Header on boot device
2826 56 common/cmd_nand.c reading Image Header from NAND device OK
2827 -57 common/cmd_nand.c Image header has bad magic number
2828 57 common/cmd_nand.c Image header has correct magic number
2829 -58 common/cmd_nand.c Error reading Image from NAND device
2830 58 common/cmd_nand.c reading Image from NAND device OK
2832 -60 common/env_common.c Environment has a bad CRC, using default
2834 64 net/eth.c starting with Ethernet configuration.
2835 -64 net/eth.c no Ethernet found.
2836 65 net/eth.c Ethernet found.
2838 -80 common/cmd_net.c usage wrong
2839 80 common/cmd_net.c before calling net_loop()
2840 -81 common/cmd_net.c some error in net_loop() occurred
2841 81 common/cmd_net.c net_loop() back without error
2842 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
2843 82 common/cmd_net.c trying automatic boot
2844 83 common/cmd_net.c running "source" command
2845 -83 common/cmd_net.c some error in automatic boot or "source" command
2846 84 common/cmd_net.c end without errors
2851 100 common/cmd_bootm.c Kernel FIT Image has correct format
2852 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
2853 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
2854 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
2855 102 common/cmd_bootm.c Kernel unit name specified
2856 -103 common/cmd_bootm.c Can't get kernel subimage node offset
2857 103 common/cmd_bootm.c Found configuration node
2858 104 common/cmd_bootm.c Got kernel subimage node offset
2859 -104 common/cmd_bootm.c Kernel subimage hash verification failed
2860 105 common/cmd_bootm.c Kernel subimage hash verification OK
2861 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
2862 106 common/cmd_bootm.c Architecture check OK
2863 -106 common/cmd_bootm.c Kernel subimage has wrong type
2864 107 common/cmd_bootm.c Kernel subimage type OK
2865 -107 common/cmd_bootm.c Can't get kernel subimage data/size
2866 108 common/cmd_bootm.c Got kernel subimage data/size
2867 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
2868 -109 common/cmd_bootm.c Can't get kernel subimage type
2869 -110 common/cmd_bootm.c Can't get kernel subimage comp
2870 -111 common/cmd_bootm.c Can't get kernel subimage os
2871 -112 common/cmd_bootm.c Can't get kernel subimage load address
2872 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
2874 120 common/image.c Start initial ramdisk verification
2875 -120 common/image.c Ramdisk FIT image has incorrect format
2876 121 common/image.c Ramdisk FIT image has correct format
2877 122 common/image.c No ramdisk subimage unit name, using configuration
2878 -122 common/image.c Can't get configuration for ramdisk subimage
2879 123 common/image.c Ramdisk unit name specified
2880 -124 common/image.c Can't get ramdisk subimage node offset
2881 125 common/image.c Got ramdisk subimage node offset
2882 -125 common/image.c Ramdisk subimage hash verification failed
2883 126 common/image.c Ramdisk subimage hash verification OK
2884 -126 common/image.c Ramdisk subimage for unsupported architecture
2885 127 common/image.c Architecture check OK
2886 -127 common/image.c Can't get ramdisk subimage data/size
2887 128 common/image.c Got ramdisk subimage data/size
2888 129 common/image.c Can't get ramdisk load address
2889 -129 common/image.c Got ramdisk load address
2891 -130 common/cmd_doc.c Incorrect FIT image format
2892 131 common/cmd_doc.c FIT image format OK
2894 -140 common/cmd_ide.c Incorrect FIT image format
2895 141 common/cmd_ide.c FIT image format OK
2897 -150 common/cmd_nand.c Incorrect FIT image format
2898 151 common/cmd_nand.c FIT image format OK
2900 - legacy image format:
2901 CONFIG_IMAGE_FORMAT_LEGACY
2902 enables the legacy image format support in U-Boot.
2905 enabled if CONFIG_FIT_SIGNATURE is not defined.
2907 CONFIG_DISABLE_IMAGE_LEGACY
2908 disable the legacy image format
2910 This define is introduced, as the legacy image format is
2911 enabled per default for backward compatibility.
2913 - Standalone program support:
2914 CONFIG_STANDALONE_LOAD_ADDR
2916 This option defines a board specific value for the
2917 address where standalone program gets loaded, thus
2918 overwriting the architecture dependent default
2921 - Frame Buffer Address:
2924 Define CONFIG_FB_ADDR if you want to use specific
2925 address for frame buffer. This is typically the case
2926 when using a graphics controller has separate video
2927 memory. U-Boot will then place the frame buffer at
2928 the given address instead of dynamically reserving it
2929 in system RAM by calling lcd_setmem(), which grabs
2930 the memory for the frame buffer depending on the
2931 configured panel size.
2933 Please see board_init_f function.
2935 - Automatic software updates via TFTP server
2937 CONFIG_UPDATE_TFTP_CNT_MAX
2938 CONFIG_UPDATE_TFTP_MSEC_MAX
2940 These options enable and control the auto-update feature;
2941 for a more detailed description refer to doc/README.update.
2943 - MTD Support (mtdparts command, UBI support)
2946 Adds the MTD device infrastructure from the Linux kernel.
2947 Needed for mtdparts command support.
2949 CONFIG_MTD_PARTITIONS
2951 Adds the MTD partitioning infrastructure from the Linux
2952 kernel. Needed for UBI support.
2957 Adds commands for interacting with MTD partitions formatted
2958 with the UBI flash translation layer
2960 Requires also defining CONFIG_RBTREE
2962 CONFIG_UBI_SILENCE_MSG
2964 Make the verbose messages from UBI stop printing. This leaves
2965 warnings and errors enabled.
2968 CONFIG_MTD_UBI_WL_THRESHOLD
2969 This parameter defines the maximum difference between the highest
2970 erase counter value and the lowest erase counter value of eraseblocks
2971 of UBI devices. When this threshold is exceeded, UBI starts performing
2972 wear leveling by means of moving data from eraseblock with low erase
2973 counter to eraseblocks with high erase counter.
2975 The default value should be OK for SLC NAND flashes, NOR flashes and
2976 other flashes which have eraseblock life-cycle 100000 or more.
2977 However, in case of MLC NAND flashes which typically have eraseblock
2978 life-cycle less than 10000, the threshold should be lessened (e.g.,
2979 to 128 or 256, although it does not have to be power of 2).
2983 CONFIG_MTD_UBI_BEB_LIMIT
2984 This option specifies the maximum bad physical eraseblocks UBI
2985 expects on the MTD device (per 1024 eraseblocks). If the
2986 underlying flash does not admit of bad eraseblocks (e.g. NOR
2987 flash), this value is ignored.
2989 NAND datasheets often specify the minimum and maximum NVM
2990 (Number of Valid Blocks) for the flashes' endurance lifetime.
2991 The maximum expected bad eraseblocks per 1024 eraseblocks
2992 then can be calculated as "1024 * (1 - MinNVB / MaxNVB)",
2993 which gives 20 for most NANDs (MaxNVB is basically the total
2994 count of eraseblocks on the chip).
2996 To put it differently, if this value is 20, UBI will try to
2997 reserve about 1.9% of physical eraseblocks for bad blocks
2998 handling. And that will be 1.9% of eraseblocks on the entire
2999 NAND chip, not just the MTD partition UBI attaches. This means
3000 that if you have, say, a NAND flash chip admits maximum 40 bad
3001 eraseblocks, and it is split on two MTD partitions of the same
3002 size, UBI will reserve 40 eraseblocks when attaching a
3007 CONFIG_MTD_UBI_FASTMAP
3008 Fastmap is a mechanism which allows attaching an UBI device
3009 in nearly constant time. Instead of scanning the whole MTD device it
3010 only has to locate a checkpoint (called fastmap) on the device.
3011 The on-flash fastmap contains all information needed to attach
3012 the device. Using fastmap makes only sense on large devices where
3013 attaching by scanning takes long. UBI will not automatically install
3014 a fastmap on old images, but you can set the UBI parameter
3015 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT to 1 if you want so. Please note
3016 that fastmap-enabled images are still usable with UBI implementations
3017 without fastmap support. On typical flash devices the whole fastmap
3018 fits into one PEB. UBI will reserve PEBs to hold two fastmaps.
3020 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT
3021 Set this parameter to enable fastmap automatically on images
3025 CONFIG_MTD_UBI_FM_DEBUG
3026 Enable UBI fastmap debug
3032 Adds commands for interacting with UBI volumes formatted as
3033 UBIFS. UBIFS is read-only in u-boot.
3035 Requires UBI support as well as CONFIG_LZO
3037 CONFIG_UBIFS_SILENCE_MSG
3039 Make the verbose messages from UBIFS stop printing. This leaves
3040 warnings and errors enabled.
3044 Enable building of SPL globally.
3047 LDSCRIPT for linking the SPL binary.
3049 CONFIG_SPL_MAX_FOOTPRINT
3050 Maximum size in memory allocated to the SPL, BSS included.
3051 When defined, the linker checks that the actual memory
3052 used by SPL from _start to __bss_end does not exceed it.
3053 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3054 must not be both defined at the same time.
3057 Maximum size of the SPL image (text, data, rodata, and
3058 linker lists sections), BSS excluded.
3059 When defined, the linker checks that the actual size does
3062 CONFIG_SPL_TEXT_BASE
3063 TEXT_BASE for linking the SPL binary.
3065 CONFIG_SPL_RELOC_TEXT_BASE
3066 Address to relocate to. If unspecified, this is equal to
3067 CONFIG_SPL_TEXT_BASE (i.e. no relocation is done).
3069 CONFIG_SPL_BSS_START_ADDR
3070 Link address for the BSS within the SPL binary.
3072 CONFIG_SPL_BSS_MAX_SIZE
3073 Maximum size in memory allocated to the SPL BSS.
3074 When defined, the linker checks that the actual memory used
3075 by SPL from __bss_start to __bss_end does not exceed it.
3076 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3077 must not be both defined at the same time.
3080 Adress of the start of the stack SPL will use
3082 CONFIG_SPL_PANIC_ON_RAW_IMAGE
3083 When defined, SPL will panic() if the image it has
3084 loaded does not have a signature.
3085 Defining this is useful when code which loads images
3086 in SPL cannot guarantee that absolutely all read errors
3088 An example is the LPC32XX MLC NAND driver, which will
3089 consider that a completely unreadable NAND block is bad,
3090 and thus should be skipped silently.
3092 CONFIG_SPL_RELOC_STACK
3093 Adress of the start of the stack SPL will use after
3094 relocation. If unspecified, this is equal to
3097 CONFIG_SYS_SPL_MALLOC_START
3098 Starting address of the malloc pool used in SPL.
3099 When this option is set the full malloc is used in SPL and
3100 it is set up by spl_init() and before that, the simple malloc()
3101 can be used if CONFIG_SYS_MALLOC_F is defined.
3103 CONFIG_SYS_SPL_MALLOC_SIZE
3104 The size of the malloc pool used in SPL.
3106 CONFIG_SPL_FRAMEWORK
3107 Enable the SPL framework under common/. This framework
3108 supports MMC, NAND and YMODEM loading of U-Boot and NAND
3109 NAND loading of the Linux Kernel.
3112 Enable booting directly to an OS from SPL.
3113 See also: doc/README.falcon
3115 CONFIG_SPL_DISPLAY_PRINT
3116 For ARM, enable an optional function to print more information
3117 about the running system.
3119 CONFIG_SPL_INIT_MINIMAL
3120 Arch init code should be built for a very small image
3122 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_PARTITION
3123 Partition on the MMC to load U-Boot from when the MMC is being
3126 CONFIG_SYS_MMCSD_RAW_MODE_KERNEL_SECTOR
3127 Sector to load kernel uImage from when MMC is being
3128 used in raw mode (for Falcon mode)
3130 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTOR,
3131 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTORS
3132 Sector and number of sectors to load kernel argument
3133 parameters from when MMC is being used in raw mode
3136 CONFIG_SYS_MMCSD_FS_BOOT_PARTITION
3137 Partition on the MMC to load U-Boot from when the MMC is being
3140 CONFIG_SPL_FS_LOAD_PAYLOAD_NAME
3141 Filename to read to load U-Boot when reading from filesystem
3143 CONFIG_SPL_FS_LOAD_KERNEL_NAME
3144 Filename to read to load kernel uImage when reading
3145 from filesystem (for Falcon mode)
3147 CONFIG_SPL_FS_LOAD_ARGS_NAME
3148 Filename to read to load kernel argument parameters
3149 when reading from filesystem (for Falcon mode)
3151 CONFIG_SPL_MPC83XX_WAIT_FOR_NAND
3152 Set this for NAND SPL on PPC mpc83xx targets, so that
3153 start.S waits for the rest of the SPL to load before
3154 continuing (the hardware starts execution after just
3155 loading the first page rather than the full 4K).
3157 CONFIG_SPL_SKIP_RELOCATE
3158 Avoid SPL relocation
3160 CONFIG_SPL_NAND_BASE
3161 Include nand_base.c in the SPL. Requires
3162 CONFIG_SPL_NAND_DRIVERS.
3164 CONFIG_SPL_NAND_DRIVERS
3165 SPL uses normal NAND drivers, not minimal drivers.
3168 Include standard software ECC in the SPL
3170 CONFIG_SPL_NAND_SIMPLE
3171 Support for NAND boot using simple NAND drivers that
3172 expose the cmd_ctrl() interface.
3175 Support for a lightweight UBI (fastmap) scanner and
3178 CONFIG_SPL_NAND_RAW_ONLY
3179 Support to boot only raw u-boot.bin images. Use this only
3180 if you need to save space.
3182 CONFIG_SPL_COMMON_INIT_DDR
3183 Set for common ddr init with serial presence detect in
3186 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
3187 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
3188 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
3189 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
3190 CONFIG_SYS_NAND_ECCBYTES
3191 Defines the size and behavior of the NAND that SPL uses
3194 CONFIG_SPL_NAND_BOOT
3195 Add support NAND boot
3197 CONFIG_SYS_NAND_U_BOOT_OFFS
3198 Location in NAND to read U-Boot from
3200 CONFIG_SYS_NAND_U_BOOT_DST
3201 Location in memory to load U-Boot to
3203 CONFIG_SYS_NAND_U_BOOT_SIZE
3204 Size of image to load
3206 CONFIG_SYS_NAND_U_BOOT_START
3207 Entry point in loaded image to jump to
3209 CONFIG_SYS_NAND_HW_ECC_OOBFIRST
3210 Define this if you need to first read the OOB and then the
3211 data. This is used, for example, on davinci platforms.
3213 CONFIG_SPL_OMAP3_ID_NAND
3214 Support for an OMAP3-specific set of functions to return the
3215 ID and MFR of the first attached NAND chip, if present.
3217 CONFIG_SPL_RAM_DEVICE
3218 Support for running image already present in ram, in SPL binary
3221 Image offset to which the SPL should be padded before appending
3222 the SPL payload. By default, this is defined as
3223 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3224 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3225 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3228 Final target image containing SPL and payload. Some SPLs
3229 use an arch-specific makefile fragment instead, for
3230 example if more than one image needs to be produced.
3232 CONFIG_FIT_SPL_PRINT
3233 Printing information about a FIT image adds quite a bit of
3234 code to SPL. So this is normally disabled in SPL. Use this
3235 option to re-enable it. This will affect the output of the
3236 bootm command when booting a FIT image.
3240 Enable building of TPL globally.
3243 Image offset to which the TPL should be padded before appending
3244 the TPL payload. By default, this is defined as
3245 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3246 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3247 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3249 - Interrupt support (PPC):
3251 There are common interrupt_init() and timer_interrupt()
3252 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
3253 for CPU specific initialization. interrupt_init_cpu()
3254 should set decrementer_count to appropriate value. If
3255 CPU resets decrementer automatically after interrupt
3256 (ppc4xx) it should set decrementer_count to zero.
3257 timer_interrupt() calls timer_interrupt_cpu() for CPU
3258 specific handling. If board has watchdog / status_led
3259 / other_activity_monitor it works automatically from
3260 general timer_interrupt().
3263 Board initialization settings:
3264 ------------------------------
3266 During Initialization u-boot calls a number of board specific functions
3267 to allow the preparation of board specific prerequisites, e.g. pin setup
3268 before drivers are initialized. To enable these callbacks the
3269 following configuration macros have to be defined. Currently this is
3270 architecture specific, so please check arch/your_architecture/lib/board.c
3271 typically in board_init_f() and board_init_r().
3273 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
3274 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
3275 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
3276 - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
3278 Configuration Settings:
3279 -----------------------
3281 - CONFIG_SYS_SUPPORT_64BIT_DATA: Defined automatically if compiled as 64-bit.
3282 Optionally it can be defined to support 64-bit memory commands.
3284 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
3285 undefine this when you're short of memory.
3287 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
3288 width of the commands listed in the 'help' command output.
3290 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
3291 prompt for user input.
3293 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
3295 - CONFIG_SYS_PBSIZE: Buffer size for Console output
3297 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
3299 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
3300 the application (usually a Linux kernel) when it is
3303 - CONFIG_SYS_BAUDRATE_TABLE:
3304 List of legal baudrate settings for this board.
3306 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
3307 Begin and End addresses of the area used by the
3310 - CONFIG_SYS_ALT_MEMTEST:
3311 Enable an alternate, more extensive memory test.
3313 - CONFIG_SYS_MEMTEST_SCRATCH:
3314 Scratch address used by the alternate memory test
3315 You only need to set this if address zero isn't writeable
3317 - CONFIG_SYS_MEM_RESERVE_SECURE
3318 Only implemented for ARMv8 for now.
3319 If defined, the size of CONFIG_SYS_MEM_RESERVE_SECURE memory
3320 is substracted from total RAM and won't be reported to OS.
3321 This memory can be used as secure memory. A variable
3322 gd->arch.secure_ram is used to track the location. In systems
3323 the RAM base is not zero, or RAM is divided into banks,
3324 this variable needs to be recalcuated to get the address.
3326 - CONFIG_SYS_MEM_TOP_HIDE:
3327 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
3328 this specified memory area will get subtracted from the top
3329 (end) of RAM and won't get "touched" at all by U-Boot. By
3330 fixing up gd->ram_size the Linux kernel should gets passed
3331 the now "corrected" memory size and won't touch it either.
3332 This should work for arch/ppc and arch/powerpc. Only Linux
3333 board ports in arch/powerpc with bootwrapper support that
3334 recalculate the memory size from the SDRAM controller setup
3335 will have to get fixed in Linux additionally.
3337 This option can be used as a workaround for the 440EPx/GRx
3338 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
3341 WARNING: Please make sure that this value is a multiple of
3342 the Linux page size (normally 4k). If this is not the case,
3343 then the end address of the Linux memory will be located at a
3344 non page size aligned address and this could cause major
3347 - CONFIG_SYS_LOADS_BAUD_CHANGE:
3348 Enable temporary baudrate change while serial download
3350 - CONFIG_SYS_SDRAM_BASE:
3351 Physical start address of SDRAM. _Must_ be 0 here.
3353 - CONFIG_SYS_FLASH_BASE:
3354 Physical start address of Flash memory.
3356 - CONFIG_SYS_MONITOR_BASE:
3357 Physical start address of boot monitor code (set by
3358 make config files to be same as the text base address
3359 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
3360 CONFIG_SYS_FLASH_BASE when booting from flash.
3362 - CONFIG_SYS_MONITOR_LEN:
3363 Size of memory reserved for monitor code, used to
3364 determine _at_compile_time_ (!) if the environment is
3365 embedded within the U-Boot image, or in a separate
3368 - CONFIG_SYS_MALLOC_LEN:
3369 Size of DRAM reserved for malloc() use.
3371 - CONFIG_SYS_MALLOC_F_LEN
3372 Size of the malloc() pool for use before relocation. If
3373 this is defined, then a very simple malloc() implementation
3374 will become available before relocation. The address is just
3375 below the global data, and the stack is moved down to make
3378 This feature allocates regions with increasing addresses
3379 within the region. calloc() is supported, but realloc()
3380 is not available. free() is supported but does nothing.
3381 The memory will be freed (or in fact just forgotten) when
3382 U-Boot relocates itself.
3384 - CONFIG_SYS_MALLOC_SIMPLE
3385 Provides a simple and small malloc() and calloc() for those
3386 boards which do not use the full malloc in SPL (which is
3387 enabled with CONFIG_SYS_SPL_MALLOC_START).
3389 - CONFIG_SYS_NONCACHED_MEMORY:
3390 Size of non-cached memory area. This area of memory will be
3391 typically located right below the malloc() area and mapped
3392 uncached in the MMU. This is useful for drivers that would
3393 otherwise require a lot of explicit cache maintenance. For
3394 some drivers it's also impossible to properly maintain the
3395 cache. For example if the regions that need to be flushed
3396 are not a multiple of the cache-line size, *and* padding
3397 cannot be allocated between the regions to align them (i.e.
3398 if the HW requires a contiguous array of regions, and the
3399 size of each region is not cache-aligned), then a flush of
3400 one region may result in overwriting data that hardware has
3401 written to another region in the same cache-line. This can
3402 happen for example in network drivers where descriptors for
3403 buffers are typically smaller than the CPU cache-line (e.g.
3404 16 bytes vs. 32 or 64 bytes).
3406 Non-cached memory is only supported on 32-bit ARM at present.
3408 - CONFIG_SYS_BOOTM_LEN:
3409 Normally compressed uImages are limited to an
3410 uncompressed size of 8 MBytes. If this is not enough,
3411 you can define CONFIG_SYS_BOOTM_LEN in your board config file
3412 to adjust this setting to your needs.
3414 - CONFIG_SYS_BOOTMAPSZ:
3415 Maximum size of memory mapped by the startup code of
3416 the Linux kernel; all data that must be processed by
3417 the Linux kernel (bd_info, boot arguments, FDT blob if
3418 used) must be put below this limit, unless "bootm_low"
3419 environment variable is defined and non-zero. In such case
3420 all data for the Linux kernel must be between "bootm_low"
3421 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
3422 variable "bootm_mapsize" will override the value of
3423 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
3424 then the value in "bootm_size" will be used instead.
3426 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
3427 Enable initrd_high functionality. If defined then the
3428 initrd_high feature is enabled and the bootm ramdisk subcommand
3431 - CONFIG_SYS_BOOT_GET_CMDLINE:
3432 Enables allocating and saving kernel cmdline in space between
3433 "bootm_low" and "bootm_low" + BOOTMAPSZ.
3435 - CONFIG_SYS_BOOT_GET_KBD:
3436 Enables allocating and saving a kernel copy of the bd_info in
3437 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
3439 - CONFIG_SYS_MAX_FLASH_BANKS:
3440 Max number of Flash memory banks
3442 - CONFIG_SYS_MAX_FLASH_SECT:
3443 Max number of sectors on a Flash chip
3445 - CONFIG_SYS_FLASH_ERASE_TOUT:
3446 Timeout for Flash erase operations (in ms)
3448 - CONFIG_SYS_FLASH_WRITE_TOUT:
3449 Timeout for Flash write operations (in ms)
3451 - CONFIG_SYS_FLASH_LOCK_TOUT
3452 Timeout for Flash set sector lock bit operation (in ms)
3454 - CONFIG_SYS_FLASH_UNLOCK_TOUT
3455 Timeout for Flash clear lock bits operation (in ms)
3457 - CONFIG_SYS_FLASH_PROTECTION
3458 If defined, hardware flash sectors protection is used
3459 instead of U-Boot software protection.
3461 - CONFIG_SYS_DIRECT_FLASH_TFTP:
3463 Enable TFTP transfers directly to flash memory;
3464 without this option such a download has to be
3465 performed in two steps: (1) download to RAM, and (2)
3466 copy from RAM to flash.
3468 The two-step approach is usually more reliable, since
3469 you can check if the download worked before you erase
3470 the flash, but in some situations (when system RAM is
3471 too limited to allow for a temporary copy of the
3472 downloaded image) this option may be very useful.
3474 - CONFIG_SYS_FLASH_CFI:
3475 Define if the flash driver uses extra elements in the
3476 common flash structure for storing flash geometry.
3478 - CONFIG_FLASH_CFI_DRIVER
3479 This option also enables the building of the cfi_flash driver
3480 in the drivers directory
3482 - CONFIG_FLASH_CFI_MTD
3483 This option enables the building of the cfi_mtd driver
3484 in the drivers directory. The driver exports CFI flash
3487 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
3488 Use buffered writes to flash.
3490 - CONFIG_FLASH_SPANSION_S29WS_N
3491 s29ws-n MirrorBit flash has non-standard addresses for buffered
3494 - CONFIG_SYS_FLASH_QUIET_TEST
3495 If this option is defined, the common CFI flash doesn't
3496 print it's warning upon not recognized FLASH banks. This
3497 is useful, if some of the configured banks are only
3498 optionally available.
3500 - CONFIG_FLASH_SHOW_PROGRESS
3501 If defined (must be an integer), print out countdown
3502 digits and dots. Recommended value: 45 (9..1) for 80
3503 column displays, 15 (3..1) for 40 column displays.
3505 - CONFIG_FLASH_VERIFY
3506 If defined, the content of the flash (destination) is compared
3507 against the source after the write operation. An error message
3508 will be printed when the contents are not identical.
3509 Please note that this option is useless in nearly all cases,
3510 since such flash programming errors usually are detected earlier
3511 while unprotecting/erasing/programming. Please only enable
3512 this option if you really know what you are doing.
3514 - CONFIG_SYS_RX_ETH_BUFFER:
3515 Defines the number of Ethernet receive buffers. On some
3516 Ethernet controllers it is recommended to set this value
3517 to 8 or even higher (EEPRO100 or 405 EMAC), since all
3518 buffers can be full shortly after enabling the interface
3519 on high Ethernet traffic.
3520 Defaults to 4 if not defined.
3522 - CONFIG_ENV_MAX_ENTRIES
3524 Maximum number of entries in the hash table that is used
3525 internally to store the environment settings. The default
3526 setting is supposed to be generous and should work in most
3527 cases. This setting can be used to tune behaviour; see
3528 lib/hashtable.c for details.
3530 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3531 - CONFIG_ENV_FLAGS_LIST_STATIC
3532 Enable validation of the values given to environment variables when
3533 calling env set. Variables can be restricted to only decimal,
3534 hexadecimal, or boolean. If CONFIG_CMD_NET is also defined,
3535 the variables can also be restricted to IP address or MAC address.
3537 The format of the list is:
3538 type_attribute = [s|d|x|b|i|m]
3539 access_attribute = [a|r|o|c]
3540 attributes = type_attribute[access_attribute]
3541 entry = variable_name[:attributes]
3544 The type attributes are:
3545 s - String (default)
3548 b - Boolean ([1yYtT|0nNfF])
3552 The access attributes are:
3558 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3559 Define this to a list (string) to define the ".flags"
3560 environment variable in the default or embedded environment.
3562 - CONFIG_ENV_FLAGS_LIST_STATIC
3563 Define this to a list (string) to define validation that
3564 should be done if an entry is not found in the ".flags"
3565 environment variable. To override a setting in the static
3566 list, simply add an entry for the same variable name to the
3569 If CONFIG_REGEX is defined, the variable_name above is evaluated as a
3570 regular expression. This allows multiple variables to define the same
3571 flags without explicitly listing them for each variable.
3573 - CONFIG_ENV_ACCESS_IGNORE_FORCE
3574 If defined, don't allow the -f switch to env set override variable
3578 If stdint.h is available with your toolchain you can define this
3579 option to enable it. You can provide option 'USE_STDINT=1' when
3580 building U-Boot to enable this.
3582 The following definitions that deal with the placement and management
3583 of environment data (variable area); in general, we support the
3584 following configurations:
3586 - CONFIG_BUILD_ENVCRC:
3588 Builds up envcrc with the target environment so that external utils
3589 may easily extract it and embed it in final U-Boot images.
3591 - CONFIG_ENV_IS_IN_FLASH:
3593 Define this if the environment is in flash memory.
3595 a) The environment occupies one whole flash sector, which is
3596 "embedded" in the text segment with the U-Boot code. This
3597 happens usually with "bottom boot sector" or "top boot
3598 sector" type flash chips, which have several smaller
3599 sectors at the start or the end. For instance, such a
3600 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
3601 such a case you would place the environment in one of the
3602 4 kB sectors - with U-Boot code before and after it. With
3603 "top boot sector" type flash chips, you would put the
3604 environment in one of the last sectors, leaving a gap
3605 between U-Boot and the environment.
3607 - CONFIG_ENV_OFFSET:
3609 Offset of environment data (variable area) to the
3610 beginning of flash memory; for instance, with bottom boot
3611 type flash chips the second sector can be used: the offset
3612 for this sector is given here.
3614 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
3618 This is just another way to specify the start address of
3619 the flash sector containing the environment (instead of
3622 - CONFIG_ENV_SECT_SIZE:
3624 Size of the sector containing the environment.
3627 b) Sometimes flash chips have few, equal sized, BIG sectors.
3628 In such a case you don't want to spend a whole sector for
3633 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
3634 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
3635 of this flash sector for the environment. This saves
3636 memory for the RAM copy of the environment.
3638 It may also save flash memory if you decide to use this
3639 when your environment is "embedded" within U-Boot code,
3640 since then the remainder of the flash sector could be used
3641 for U-Boot code. It should be pointed out that this is
3642 STRONGLY DISCOURAGED from a robustness point of view:
3643 updating the environment in flash makes it always
3644 necessary to erase the WHOLE sector. If something goes
3645 wrong before the contents has been restored from a copy in
3646 RAM, your target system will be dead.
3648 - CONFIG_ENV_ADDR_REDUND
3649 CONFIG_ENV_SIZE_REDUND
3651 These settings describe a second storage area used to hold
3652 a redundant copy of the environment data, so that there is
3653 a valid backup copy in case there is a power failure during
3654 a "saveenv" operation.
3656 BE CAREFUL! Any changes to the flash layout, and some changes to the
3657 source code will make it necessary to adapt <board>/u-boot.lds*
3661 - CONFIG_ENV_IS_IN_NVRAM:
3663 Define this if you have some non-volatile memory device
3664 (NVRAM, battery buffered SRAM) which you want to use for the
3670 These two #defines are used to determine the memory area you
3671 want to use for environment. It is assumed that this memory
3672 can just be read and written to, without any special
3675 BE CAREFUL! The first access to the environment happens quite early
3676 in U-Boot initialization (when we try to get the setting of for the
3677 console baudrate). You *MUST* have mapped your NVRAM area then, or
3680 Please note that even with NVRAM we still use a copy of the
3681 environment in RAM: we could work on NVRAM directly, but we want to
3682 keep settings there always unmodified except somebody uses "saveenv"
3683 to save the current settings.
3686 - CONFIG_ENV_IS_IN_EEPROM:
3688 Use this if you have an EEPROM or similar serial access
3689 device and a driver for it.
3691 - CONFIG_ENV_OFFSET:
3694 These two #defines specify the offset and size of the
3695 environment area within the total memory of your EEPROM.
3697 - CONFIG_SYS_I2C_EEPROM_ADDR:
3698 If defined, specified the chip address of the EEPROM device.
3699 The default address is zero.
3701 - CONFIG_SYS_I2C_EEPROM_BUS:
3702 If defined, specified the i2c bus of the EEPROM device.
3704 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
3705 If defined, the number of bits used to address bytes in a
3706 single page in the EEPROM device. A 64 byte page, for example
3707 would require six bits.
3709 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
3710 If defined, the number of milliseconds to delay between
3711 page writes. The default is zero milliseconds.
3713 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
3714 The length in bytes of the EEPROM memory array address. Note
3715 that this is NOT the chip address length!
3717 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
3718 EEPROM chips that implement "address overflow" are ones
3719 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
3720 address and the extra bits end up in the "chip address" bit
3721 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
3724 Note that we consider the length of the address field to
3725 still be one byte because the extra address bits are hidden
3726 in the chip address.
3728 - CONFIG_SYS_EEPROM_SIZE:
3729 The size in bytes of the EEPROM device.
3731 - CONFIG_ENV_EEPROM_IS_ON_I2C
3732 define this, if you have I2C and SPI activated, and your
3733 EEPROM, which holds the environment, is on the I2C bus.
3735 - CONFIG_I2C_ENV_EEPROM_BUS
3736 if you have an Environment on an EEPROM reached over
3737 I2C muxes, you can define here, how to reach this
3738 EEPROM. For example:
3740 #define CONFIG_I2C_ENV_EEPROM_BUS 1
3742 EEPROM which holds the environment, is reached over
3743 a pca9547 i2c mux with address 0x70, channel 3.
3745 - CONFIG_ENV_IS_IN_DATAFLASH:
3747 Define this if you have a DataFlash memory device which you
3748 want to use for the environment.
3750 - CONFIG_ENV_OFFSET:
3754 These three #defines specify the offset and size of the
3755 environment area within the total memory of your DataFlash placed
3756 at the specified address.
3758 - CONFIG_ENV_IS_IN_SPI_FLASH:
3760 Define this if you have a SPI Flash memory device which you
3761 want to use for the environment.
3763 - CONFIG_ENV_OFFSET:
3766 These two #defines specify the offset and size of the
3767 environment area within the SPI Flash. CONFIG_ENV_OFFSET must be
3768 aligned to an erase sector boundary.
3770 - CONFIG_ENV_SECT_SIZE:
3772 Define the SPI flash's sector size.
3774 - CONFIG_ENV_OFFSET_REDUND (optional):
3776 This setting describes a second storage area of CONFIG_ENV_SIZE
3777 size used to hold a redundant copy of the environment data, so
3778 that there is a valid backup copy in case there is a power failure
3779 during a "saveenv" operation. CONFIG_ENV_OFFSET_REDUND must be
3780 aligned to an erase sector boundary.
3782 - CONFIG_ENV_SPI_BUS (optional):
3783 - CONFIG_ENV_SPI_CS (optional):
3785 Define the SPI bus and chip select. If not defined they will be 0.
3787 - CONFIG_ENV_SPI_MAX_HZ (optional):
3789 Define the SPI max work clock. If not defined then use 1MHz.
3791 - CONFIG_ENV_SPI_MODE (optional):
3793 Define the SPI work mode. If not defined then use SPI_MODE_3.
3795 - CONFIG_ENV_IS_IN_REMOTE:
3797 Define this if you have a remote memory space which you
3798 want to use for the local device's environment.
3803 These two #defines specify the address and size of the
3804 environment area within the remote memory space. The
3805 local device can get the environment from remote memory
3806 space by SRIO or PCIE links.
3808 BE CAREFUL! For some special cases, the local device can not use
3809 "saveenv" command. For example, the local device will get the
3810 environment stored in a remote NOR flash by SRIO or PCIE link,
3811 but it can not erase, write this NOR flash by SRIO or PCIE interface.
3813 - CONFIG_ENV_IS_IN_NAND:
3815 Define this if you have a NAND device which you want to use
3816 for the environment.
3818 - CONFIG_ENV_OFFSET:
3821 These two #defines specify the offset and size of the environment
3822 area within the first NAND device. CONFIG_ENV_OFFSET must be
3823 aligned to an erase block boundary.
3825 - CONFIG_ENV_OFFSET_REDUND (optional):
3827 This setting describes a second storage area of CONFIG_ENV_SIZE
3828 size used to hold a redundant copy of the environment data, so
3829 that there is a valid backup copy in case there is a power failure
3830 during a "saveenv" operation. CONFIG_ENV_OFFSET_REDUND must be
3831 aligned to an erase block boundary.
3833 - CONFIG_ENV_RANGE (optional):
3835 Specifies the length of the region in which the environment
3836 can be written. This should be a multiple of the NAND device's
3837 block size. Specifying a range with more erase blocks than
3838 are needed to hold CONFIG_ENV_SIZE allows bad blocks within
3839 the range to be avoided.
3841 - CONFIG_ENV_OFFSET_OOB (optional):
3843 Enables support for dynamically retrieving the offset of the
3844 environment from block zero's out-of-band data. The
3845 "nand env.oob" command can be used to record this offset.
3846 Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
3847 using CONFIG_ENV_OFFSET_OOB.
3849 - CONFIG_NAND_ENV_DST
3851 Defines address in RAM to which the nand_spl code should copy the
3852 environment. If redundant environment is used, it will be copied to
3853 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
3855 - CONFIG_ENV_IS_IN_UBI:
3857 Define this if you have an UBI volume that you want to use for the
3858 environment. This has the benefit of wear-leveling the environment
3859 accesses, which is important on NAND.
3861 - CONFIG_ENV_UBI_PART:
3863 Define this to a string that is the mtd partition containing the UBI.
3865 - CONFIG_ENV_UBI_VOLUME:
3867 Define this to the name of the volume that you want to store the
3870 - CONFIG_ENV_UBI_VOLUME_REDUND:
3872 Define this to the name of another volume to store a second copy of
3873 the environment in. This will enable redundant environments in UBI.
3874 It is assumed that both volumes are in the same MTD partition.
3876 - CONFIG_UBI_SILENCE_MSG
3877 - CONFIG_UBIFS_SILENCE_MSG
3879 You will probably want to define these to avoid a really noisy system
3880 when storing the env in UBI.
3882 - CONFIG_ENV_IS_IN_FAT:
3883 Define this if you want to use the FAT file system for the environment.
3885 - FAT_ENV_INTERFACE:
3887 Define this to a string that is the name of the block device.
3889 - FAT_ENV_DEVICE_AND_PART:
3891 Define this to a string to specify the partition of the device. It can
3894 "D:P", "D:0", "D", "D:" or "D:auto" (D, P are integers. And P >= 1)
3895 - "D:P": device D partition P. Error occurs if device D has no
3898 - "D" or "D:": device D partition 1 if device D has partition
3899 table, or the whole device D if has no partition
3901 - "D:auto": first partition in device D with bootable flag set.
3902 If none, first valid partition in device D. If no
3903 partition table then means device D.
3907 It's a string of the FAT file name. This file use to store the
3911 This should be defined. Otherwise it cannot save the environment file.
3913 - CONFIG_ENV_IS_IN_MMC:
3915 Define this if you have an MMC device which you want to use for the
3918 - CONFIG_SYS_MMC_ENV_DEV:
3920 Specifies which MMC device the environment is stored in.
3922 - CONFIG_SYS_MMC_ENV_PART (optional):
3924 Specifies which MMC partition the environment is stored in. If not
3925 set, defaults to partition 0, the user area. Common values might be
3926 1 (first MMC boot partition), 2 (second MMC boot partition).
3928 - CONFIG_ENV_OFFSET:
3931 These two #defines specify the offset and size of the environment
3932 area within the specified MMC device.
3934 If offset is positive (the usual case), it is treated as relative to
3935 the start of the MMC partition. If offset is negative, it is treated
3936 as relative to the end of the MMC partition. This can be useful if
3937 your board may be fitted with different MMC devices, which have
3938 different sizes for the MMC partitions, and you always want the
3939 environment placed at the very end of the partition, to leave the
3940 maximum possible space before it, to store other data.
3942 These two values are in units of bytes, but must be aligned to an
3943 MMC sector boundary.
3945 - CONFIG_ENV_OFFSET_REDUND (optional):
3947 Specifies a second storage area, of CONFIG_ENV_SIZE size, used to
3948 hold a redundant copy of the environment data. This provides a
3949 valid backup copy in case the other copy is corrupted, e.g. due
3950 to a power failure during a "saveenv" operation.
3952 This value may also be positive or negative; this is handled in the
3953 same way as CONFIG_ENV_OFFSET.
3955 This value is also in units of bytes, but must also be aligned to
3956 an MMC sector boundary.
3958 - CONFIG_ENV_SIZE_REDUND (optional):
3960 This value need not be set, even when CONFIG_ENV_OFFSET_REDUND is
3961 set. If this value is set, it must be set to the same value as
3964 - CONFIG_SYS_SPI_INIT_OFFSET
3966 Defines offset to the initial SPI buffer area in DPRAM. The
3967 area is used at an early stage (ROM part) if the environment
3968 is configured to reside in the SPI EEPROM: We need a 520 byte
3969 scratch DPRAM area. It is used between the two initialization
3970 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
3971 to be a good choice since it makes it far enough from the
3972 start of the data area as well as from the stack pointer.
3974 Please note that the environment is read-only until the monitor
3975 has been relocated to RAM and a RAM copy of the environment has been
3976 created; also, when using EEPROM you will have to use getenv_f()
3977 until then to read environment variables.
3979 The environment is protected by a CRC32 checksum. Before the monitor
3980 is relocated into RAM, as a result of a bad CRC you will be working
3981 with the compiled-in default environment - *silently*!!! [This is
3982 necessary, because the first environment variable we need is the
3983 "baudrate" setting for the console - if we have a bad CRC, we don't
3984 have any device yet where we could complain.]
3986 Note: once the monitor has been relocated, then it will complain if
3987 the default environment is used; a new CRC is computed as soon as you
3988 use the "saveenv" command to store a valid environment.
3990 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
3991 Echo the inverted Ethernet link state to the fault LED.
3993 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
3994 also needs to be defined.
3996 - CONFIG_SYS_FAULT_MII_ADDR:
3997 MII address of the PHY to check for the Ethernet link state.
3999 - CONFIG_NS16550_MIN_FUNCTIONS:
4000 Define this if you desire to only have use of the NS16550_init
4001 and NS16550_putc functions for the serial driver located at
4002 drivers/serial/ns16550.c. This option is useful for saving
4003 space for already greatly restricted images, including but not
4004 limited to NAND_SPL configurations.
4006 - CONFIG_DISPLAY_BOARDINFO
4007 Display information about the board that U-Boot is running on
4008 when U-Boot starts up. The board function checkboard() is called
4011 - CONFIG_DISPLAY_BOARDINFO_LATE
4012 Similar to the previous option, but display this information
4013 later, once stdio is running and output goes to the LCD, if
4016 - CONFIG_BOARD_SIZE_LIMIT:
4017 Maximum size of the U-Boot image. When defined, the
4018 build system checks that the actual size does not
4021 Low Level (hardware related) configuration options:
4022 ---------------------------------------------------
4024 - CONFIG_SYS_CACHELINE_SIZE:
4025 Cache Line Size of the CPU.
4027 - CONFIG_SYS_DEFAULT_IMMR:
4028 Default address of the IMMR after system reset.
4030 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
4031 and RPXsuper) to be able to adjust the position of
4032 the IMMR register after a reset.
4034 - CONFIG_SYS_CCSRBAR_DEFAULT:
4035 Default (power-on reset) physical address of CCSR on Freescale
4038 - CONFIG_SYS_CCSRBAR:
4039 Virtual address of CCSR. On a 32-bit build, this is typically
4040 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
4042 CONFIG_SYS_DEFAULT_IMMR must also be set to this value,
4043 for cross-platform code that uses that macro instead.
4045 - CONFIG_SYS_CCSRBAR_PHYS:
4046 Physical address of CCSR. CCSR can be relocated to a new
4047 physical address, if desired. In this case, this macro should
4048 be set to that address. Otherwise, it should be set to the
4049 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
4050 is typically relocated on 36-bit builds. It is recommended
4051 that this macro be defined via the _HIGH and _LOW macros:
4053 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
4054 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
4056 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
4057 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
4058 either 0 (32-bit build) or 0xF (36-bit build). This macro is
4059 used in assembly code, so it must not contain typecasts or
4060 integer size suffixes (e.g. "ULL").
4062 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
4063 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
4064 used in assembly code, so it must not contain typecasts or
4065 integer size suffixes (e.g. "ULL").
4067 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
4068 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
4069 forced to a value that ensures that CCSR is not relocated.
4071 - Floppy Disk Support:
4072 CONFIG_SYS_FDC_DRIVE_NUMBER
4074 the default drive number (default value 0)
4076 CONFIG_SYS_ISA_IO_STRIDE
4078 defines the spacing between FDC chipset registers
4081 CONFIG_SYS_ISA_IO_OFFSET
4083 defines the offset of register from address. It
4084 depends on which part of the data bus is connected to
4085 the FDC chipset. (default value 0)
4087 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
4088 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
4091 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
4092 fdc_hw_init() is called at the beginning of the FDC
4093 setup. fdc_hw_init() must be provided by the board
4094 source code. It is used to make hardware-dependent
4098 Most IDE controllers were designed to be connected with PCI
4099 interface. Only few of them were designed for AHB interface.
4100 When software is doing ATA command and data transfer to
4101 IDE devices through IDE-AHB controller, some additional
4102 registers accessing to these kind of IDE-AHB controller
4105 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
4106 DO NOT CHANGE unless you know exactly what you're
4107 doing! (11-4) [MPC8xx/82xx systems only]
4109 - CONFIG_SYS_INIT_RAM_ADDR:
4111 Start address of memory area that can be used for
4112 initial data and stack; please note that this must be
4113 writable memory that is working WITHOUT special
4114 initialization, i. e. you CANNOT use normal RAM which
4115 will become available only after programming the
4116 memory controller and running certain initialization
4119 U-Boot uses the following memory types:
4120 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
4121 - MPC824X: data cache
4122 - PPC4xx: data cache
4124 - CONFIG_SYS_GBL_DATA_OFFSET:
4126 Offset of the initial data structure in the memory
4127 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
4128 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
4129 data is located at the end of the available space
4130 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
4131 GENERATED_GBL_DATA_SIZE), and the initial stack is just
4132 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
4133 CONFIG_SYS_GBL_DATA_OFFSET) downward.
4136 On the MPC824X (or other systems that use the data
4137 cache for initial memory) the address chosen for
4138 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
4139 point to an otherwise UNUSED address space between
4140 the top of RAM and the start of the PCI space.
4142 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
4144 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
4146 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
4148 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
4150 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
4152 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
4154 - CONFIG_SYS_OR_TIMING_SDRAM:
4157 - CONFIG_SYS_MAMR_PTA:
4158 periodic timer for refresh
4160 - CONFIG_SYS_DER: Debug Event Register (37-47)
4162 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
4163 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
4164 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
4165 CONFIG_SYS_BR1_PRELIM:
4166 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
4168 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
4169 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
4170 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
4171 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
4173 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
4174 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
4175 Machine Mode Register and Memory Periodic Timer
4176 Prescaler definitions (SDRAM timing)
4178 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
4179 enable I2C microcode relocation patch (MPC8xx);
4180 define relocation offset in DPRAM [DSP2]
4182 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
4183 enable SMC microcode relocation patch (MPC8xx);
4184 define relocation offset in DPRAM [SMC1]
4186 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
4187 enable SPI microcode relocation patch (MPC8xx);
4188 define relocation offset in DPRAM [SCC4]
4190 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
4191 Offset of the bootmode word in DPRAM used by post
4192 (Power On Self Tests). This definition overrides
4193 #define'd default value in commproc.h resp.
4196 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
4197 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
4198 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
4199 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
4200 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
4201 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
4202 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
4203 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
4204 Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
4206 - CONFIG_PCI_DISABLE_PCIE:
4207 Disable PCI-Express on systems where it is supported but not
4210 - CONFIG_PCI_ENUM_ONLY
4211 Only scan through and get the devices on the buses.
4212 Don't do any setup work, presumably because someone or
4213 something has already done it, and we don't need to do it
4214 a second time. Useful for platforms that are pre-booted
4215 by coreboot or similar.
4217 - CONFIG_PCI_INDIRECT_BRIDGE:
4218 Enable support for indirect PCI bridges.
4221 Chip has SRIO or not
4224 Board has SRIO 1 port available
4227 Board has SRIO 2 port available
4229 - CONFIG_SRIO_PCIE_BOOT_MASTER
4230 Board can support master function for Boot from SRIO and PCIE
4232 - CONFIG_SYS_SRIOn_MEM_VIRT:
4233 Virtual Address of SRIO port 'n' memory region
4235 - CONFIG_SYS_SRIOn_MEM_PHYS:
4236 Physical Address of SRIO port 'n' memory region
4238 - CONFIG_SYS_SRIOn_MEM_SIZE:
4239 Size of SRIO port 'n' memory region
4241 - CONFIG_SYS_NAND_BUSWIDTH_16BIT
4242 Defined to tell the NAND controller that the NAND chip is using
4244 Not all NAND drivers use this symbol.
4245 Example of drivers that use it:
4246 - drivers/mtd/nand/ndfc.c
4247 - drivers/mtd/nand/mxc_nand.c
4249 - CONFIG_SYS_NDFC_EBC0_CFG
4250 Sets the EBC0_CFG register for the NDFC. If not defined
4251 a default value will be used.
4254 Get DDR timing information from an I2C EEPROM. Common
4255 with pluggable memory modules such as SODIMMs
4258 I2C address of the SPD EEPROM
4260 - CONFIG_SYS_SPD_BUS_NUM
4261 If SPD EEPROM is on an I2C bus other than the first
4262 one, specify here. Note that the value must resolve
4263 to something your driver can deal with.
4265 - CONFIG_SYS_DDR_RAW_TIMING
4266 Get DDR timing information from other than SPD. Common with
4267 soldered DDR chips onboard without SPD. DDR raw timing
4268 parameters are extracted from datasheet and hard-coded into
4269 header files or board specific files.
4271 - CONFIG_FSL_DDR_INTERACTIVE
4272 Enable interactive DDR debugging. See doc/README.fsl-ddr.
4274 - CONFIG_FSL_DDR_SYNC_REFRESH
4275 Enable sync of refresh for multiple controllers.
4277 - CONFIG_FSL_DDR_BIST
4278 Enable built-in memory test for Freescale DDR controllers.
4280 - CONFIG_SYS_83XX_DDR_USES_CS0
4281 Only for 83xx systems. If specified, then DDR should
4282 be configured using CS0 and CS1 instead of CS2 and CS3.
4284 - CONFIG_ETHER_ON_FEC[12]
4285 Define to enable FEC[12] on a 8xx series processor.
4287 - CONFIG_FEC[12]_PHY
4288 Define to the hardcoded PHY address which corresponds
4289 to the given FEC; i. e.
4290 #define CONFIG_FEC1_PHY 4
4291 means that the PHY with address 4 is connected to FEC1
4293 When set to -1, means to probe for first available.
4295 - CONFIG_FEC[12]_PHY_NORXERR
4296 The PHY does not have a RXERR line (RMII only).
4297 (so program the FEC to ignore it).
4300 Enable RMII mode for all FECs.
4301 Note that this is a global option, we can't
4302 have one FEC in standard MII mode and another in RMII mode.
4304 - CONFIG_CRC32_VERIFY
4305 Add a verify option to the crc32 command.
4308 => crc32 -v <address> <count> <crc32>
4310 Where address/count indicate a memory area
4311 and crc32 is the correct crc32 which the
4315 Add the "loopw" memory command. This only takes effect if
4316 the memory commands are activated globally (CONFIG_CMD_MEM).
4319 Add the "mdc" and "mwc" memory commands. These are cyclic
4324 This command will print 4 bytes (10,11,12,13) each 500 ms.
4326 => mwc.l 100 12345678 10
4327 This command will write 12345678 to address 100 all 10 ms.
4329 This only takes effect if the memory commands are activated
4330 globally (CONFIG_CMD_MEM).
4332 - CONFIG_SKIP_LOWLEVEL_INIT
4333 [ARM, NDS32, MIPS only] If this variable is defined, then certain
4334 low level initializations (like setting up the memory
4335 controller) are omitted and/or U-Boot does not
4336 relocate itself into RAM.
4338 Normally this variable MUST NOT be defined. The only
4339 exception is when U-Boot is loaded (to RAM) by some
4340 other boot loader or by a debugger which performs
4341 these initializations itself.
4343 - CONFIG_SKIP_LOWLEVEL_INIT_ONLY
4344 [ARM926EJ-S only] This allows just the call to lowlevel_init()
4345 to be skipped. The normal CP15 init (such as enabling the
4346 instruction cache) is still performed.
4349 Modifies the behaviour of start.S when compiling a loader
4350 that is executed before the actual U-Boot. E.g. when
4351 compiling a NAND SPL.
4354 Modifies the behaviour of start.S when compiling a loader
4355 that is executed after the SPL and before the actual U-Boot.
4356 It is loaded by the SPL.
4358 - CONFIG_SYS_MPC85XX_NO_RESETVEC
4359 Only for 85xx systems. If this variable is specified, the section
4360 .resetvec is not kept and the section .bootpg is placed in the
4361 previous 4k of the .text section.
4363 - CONFIG_ARCH_MAP_SYSMEM
4364 Generally U-Boot (and in particular the md command) uses
4365 effective address. It is therefore not necessary to regard
4366 U-Boot address as virtual addresses that need to be translated
4367 to physical addresses. However, sandbox requires this, since
4368 it maintains its own little RAM buffer which contains all
4369 addressable memory. This option causes some memory accesses
4370 to be mapped through map_sysmem() / unmap_sysmem().
4372 - CONFIG_X86_RESET_VECTOR
4373 If defined, the x86 reset vector code is included. This is not
4374 needed when U-Boot is running from Coreboot.
4376 - CONFIG_SPL_AM33XX_ENABLE_RTC32K_OSC:
4377 Enables the RTC32K OSC on AM33xx based plattforms
4379 - CONFIG_SYS_NAND_NO_SUBPAGE_WRITE
4380 Option to disable subpage write in NAND driver
4381 driver that uses this:
4382 drivers/mtd/nand/davinci_nand.c
4384 Freescale QE/FMAN Firmware Support:
4385 -----------------------------------
4387 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
4388 loading of "firmware", which is encoded in the QE firmware binary format.
4389 This firmware often needs to be loaded during U-Boot booting, so macros
4390 are used to identify the storage device (NOR flash, SPI, etc) and the address
4393 - CONFIG_SYS_FMAN_FW_ADDR
4394 The address in the storage device where the FMAN microcode is located. The
4395 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4398 - CONFIG_SYS_QE_FW_ADDR
4399 The address in the storage device where the QE microcode is located. The
4400 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4403 - CONFIG_SYS_QE_FMAN_FW_LENGTH
4404 The maximum possible size of the firmware. The firmware binary format
4405 has a field that specifies the actual size of the firmware, but it
4406 might not be possible to read any part of the firmware unless some
4407 local storage is allocated to hold the entire firmware first.
4409 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
4410 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
4411 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
4412 virtual address in NOR flash.
4414 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
4415 Specifies that QE/FMAN firmware is located in NAND flash.
4416 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
4418 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
4419 Specifies that QE/FMAN firmware is located on the primary SD/MMC
4420 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
4422 - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
4423 Specifies that QE/FMAN firmware is located in the remote (master)
4424 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
4425 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
4426 window->master inbound window->master LAW->the ucode address in
4427 master's memory space.
4429 Freescale Layerscape Management Complex Firmware Support:
4430 ---------------------------------------------------------
4431 The Freescale Layerscape Management Complex (MC) supports the loading of
4433 This firmware often needs to be loaded during U-Boot booting, so macros
4434 are used to identify the storage device (NOR flash, SPI, etc) and the address
4437 - CONFIG_FSL_MC_ENET
4438 Enable the MC driver for Layerscape SoCs.
4440 Freescale Layerscape Debug Server Support:
4441 -------------------------------------------
4442 The Freescale Layerscape Debug Server Support supports the loading of
4443 "Debug Server firmware" and triggering SP boot-rom.
4444 This firmware often needs to be loaded during U-Boot booting.
4446 - CONFIG_SYS_MC_RSV_MEM_ALIGN
4447 Define alignment of reserved memory MC requires
4452 In order to achieve reproducible builds, timestamps used in the U-Boot build
4453 process have to be set to a fixed value.
4455 This is done using the SOURCE_DATE_EPOCH environment variable.
4456 SOURCE_DATE_EPOCH is to be set on the build host's shell, not as a configuration
4457 option for U-Boot or an environment variable in U-Boot.
4459 SOURCE_DATE_EPOCH should be set to a number of seconds since the epoch, in UTC.
4461 Building the Software:
4462 ======================
4464 Building U-Boot has been tested in several native build environments
4465 and in many different cross environments. Of course we cannot support
4466 all possibly existing versions of cross development tools in all
4467 (potentially obsolete) versions. In case of tool chain problems we
4468 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
4469 which is extensively used to build and test U-Boot.
4471 If you are not using a native environment, it is assumed that you
4472 have GNU cross compiling tools available in your path. In this case,
4473 you must set the environment variable CROSS_COMPILE in your shell.
4474 Note that no changes to the Makefile or any other source files are
4475 necessary. For example using the ELDK on a 4xx CPU, please enter:
4477 $ CROSS_COMPILE=ppc_4xx-
4478 $ export CROSS_COMPILE
4480 Note: If you wish to generate Windows versions of the utilities in
4481 the tools directory you can use the MinGW toolchain
4482 (http://www.mingw.org). Set your HOST tools to the MinGW
4483 toolchain and execute 'make tools'. For example:
4485 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
4487 Binaries such as tools/mkimage.exe will be created which can
4488 be executed on computers running Windows.
4490 U-Boot is intended to be simple to build. After installing the
4491 sources you must configure U-Boot for one specific board type. This
4496 where "NAME_defconfig" is the name of one of the existing configu-
4497 rations; see boards.cfg for supported names.
4499 Note: for some board special configuration names may exist; check if
4500 additional information is available from the board vendor; for
4501 instance, the TQM823L systems are available without (standard)
4502 or with LCD support. You can select such additional "features"
4503 when choosing the configuration, i. e.
4505 make TQM823L_defconfig
4506 - will configure for a plain TQM823L, i. e. no LCD support
4508 make TQM823L_LCD_defconfig
4509 - will configure for a TQM823L with U-Boot console on LCD
4514 Finally, type "make all", and you should get some working U-Boot
4515 images ready for download to / installation on your system:
4517 - "u-boot.bin" is a raw binary image
4518 - "u-boot" is an image in ELF binary format
4519 - "u-boot.srec" is in Motorola S-Record format
4521 By default the build is performed locally and the objects are saved
4522 in the source directory. One of the two methods can be used to change
4523 this behavior and build U-Boot to some external directory:
4525 1. Add O= to the make command line invocations:
4527 make O=/tmp/build distclean
4528 make O=/tmp/build NAME_defconfig
4529 make O=/tmp/build all
4531 2. Set environment variable KBUILD_OUTPUT to point to the desired location:
4533 export KBUILD_OUTPUT=/tmp/build
4538 Note that the command line "O=" setting overrides the KBUILD_OUTPUT environment
4542 Please be aware that the Makefiles assume you are using GNU make, so
4543 for instance on NetBSD you might need to use "gmake" instead of
4547 If the system board that you have is not listed, then you will need
4548 to port U-Boot to your hardware platform. To do this, follow these
4551 1. Create a new directory to hold your board specific code. Add any
4552 files you need. In your board directory, you will need at least
4553 the "Makefile" and a "<board>.c".
4554 2. Create a new configuration file "include/configs/<board>.h" for
4556 3. If you're porting U-Boot to a new CPU, then also create a new
4557 directory to hold your CPU specific code. Add any files you need.
4558 4. Run "make <board>_defconfig" with your new name.
4559 5. Type "make", and you should get a working "u-boot.srec" file
4560 to be installed on your target system.
4561 6. Debug and solve any problems that might arise.
4562 [Of course, this last step is much harder than it sounds.]
4565 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
4566 ==============================================================
4568 If you have modified U-Boot sources (for instance added a new board
4569 or support for new devices, a new CPU, etc.) you are expected to
4570 provide feedback to the other developers. The feedback normally takes
4571 the form of a "patch", i. e. a context diff against a certain (latest
4572 official or latest in the git repository) version of U-Boot sources.
4574 But before you submit such a patch, please verify that your modifi-
4575 cation did not break existing code. At least make sure that *ALL* of
4576 the supported boards compile WITHOUT ANY compiler warnings. To do so,
4577 just run the buildman script (tools/buildman/buildman), which will
4578 configure and build U-Boot for ALL supported system. Be warned, this
4579 will take a while. Please see the buildman README, or run 'buildman -H'
4583 See also "U-Boot Porting Guide" below.
4586 Monitor Commands - Overview:
4587 ============================
4589 go - start application at address 'addr'
4590 run - run commands in an environment variable
4591 bootm - boot application image from memory
4592 bootp - boot image via network using BootP/TFTP protocol
4593 bootz - boot zImage from memory
4594 tftpboot- boot image via network using TFTP protocol
4595 and env variables "ipaddr" and "serverip"
4596 (and eventually "gatewayip")
4597 tftpput - upload a file via network using TFTP protocol
4598 rarpboot- boot image via network using RARP/TFTP protocol
4599 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
4600 loads - load S-Record file over serial line
4601 loadb - load binary file over serial line (kermit mode)
4603 mm - memory modify (auto-incrementing)
4604 nm - memory modify (constant address)
4605 mw - memory write (fill)
4607 cmp - memory compare
4608 crc32 - checksum calculation
4609 i2c - I2C sub-system
4610 sspi - SPI utility commands
4611 base - print or set address offset
4612 printenv- print environment variables
4613 setenv - set environment variables
4614 saveenv - save environment variables to persistent storage
4615 protect - enable or disable FLASH write protection
4616 erase - erase FLASH memory
4617 flinfo - print FLASH memory information
4618 nand - NAND memory operations (see doc/README.nand)
4619 bdinfo - print Board Info structure
4620 iminfo - print header information for application image
4621 coninfo - print console devices and informations
4622 ide - IDE sub-system
4623 loop - infinite loop on address range
4624 loopw - infinite write loop on address range
4625 mtest - simple RAM test
4626 icache - enable or disable instruction cache
4627 dcache - enable or disable data cache
4628 reset - Perform RESET of the CPU
4629 echo - echo args to console
4630 version - print monitor version
4631 help - print online help
4632 ? - alias for 'help'
4635 Monitor Commands - Detailed Description:
4636 ========================================
4640 For now: just type "help <command>".
4643 Environment Variables:
4644 ======================
4646 U-Boot supports user configuration using Environment Variables which
4647 can be made persistent by saving to Flash memory.
4649 Environment Variables are set using "setenv", printed using
4650 "printenv", and saved to Flash using "saveenv". Using "setenv"
4651 without a value can be used to delete a variable from the
4652 environment. As long as you don't save the environment you are
4653 working with an in-memory copy. In case the Flash area containing the
4654 environment is erased by accident, a default environment is provided.
4656 Some configuration options can be set using Environment Variables.
4658 List of environment variables (most likely not complete):
4660 baudrate - see CONFIG_BAUDRATE
4662 bootdelay - see CONFIG_BOOTDELAY
4664 bootcmd - see CONFIG_BOOTCOMMAND
4666 bootargs - Boot arguments when booting an RTOS image
4668 bootfile - Name of the image to load with TFTP
4670 bootm_low - Memory range available for image processing in the bootm
4671 command can be restricted. This variable is given as
4672 a hexadecimal number and defines lowest address allowed
4673 for use by the bootm command. See also "bootm_size"
4674 environment variable. Address defined by "bootm_low" is
4675 also the base of the initial memory mapping for the Linux
4676 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
4679 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
4680 This variable is given as a hexadecimal number and it
4681 defines the size of the memory region starting at base
4682 address bootm_low that is accessible by the Linux kernel
4683 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
4684 as the default value if it is defined, and bootm_size is
4687 bootm_size - Memory range available for image processing in the bootm
4688 command can be restricted. This variable is given as
4689 a hexadecimal number and defines the size of the region
4690 allowed for use by the bootm command. See also "bootm_low"
4691 environment variable.
4693 updatefile - Location of the software update file on a TFTP server, used
4694 by the automatic software update feature. Please refer to
4695 documentation in doc/README.update for more details.
4697 autoload - if set to "no" (any string beginning with 'n'),
4698 "bootp" will just load perform a lookup of the
4699 configuration from the BOOTP server, but not try to
4700 load any image using TFTP
4702 autostart - if set to "yes", an image loaded using the "bootp",
4703 "rarpboot", "tftpboot" or "diskboot" commands will
4704 be automatically started (by internally calling
4707 If set to "no", a standalone image passed to the
4708 "bootm" command will be copied to the load address
4709 (and eventually uncompressed), but NOT be started.
4710 This can be used to load and uncompress arbitrary
4713 fdt_high - if set this restricts the maximum address that the
4714 flattened device tree will be copied into upon boot.
4715 For example, if you have a system with 1 GB memory
4716 at physical address 0x10000000, while Linux kernel
4717 only recognizes the first 704 MB as low memory, you
4718 may need to set fdt_high as 0x3C000000 to have the
4719 device tree blob be copied to the maximum address
4720 of the 704 MB low memory, so that Linux kernel can
4721 access it during the boot procedure.
4723 If this is set to the special value 0xFFFFFFFF then
4724 the fdt will not be copied at all on boot. For this
4725 to work it must reside in writable memory, have
4726 sufficient padding on the end of it for u-boot to
4727 add the information it needs into it, and the memory
4728 must be accessible by the kernel.
4730 fdtcontroladdr- if set this is the address of the control flattened
4731 device tree used by U-Boot when CONFIG_OF_CONTROL is
4734 i2cfast - (PPC405GP|PPC405EP only)
4735 if set to 'y' configures Linux I2C driver for fast
4736 mode (400kHZ). This environment variable is used in
4737 initialization code. So, for changes to be effective
4738 it must be saved and board must be reset.
4740 initrd_high - restrict positioning of initrd images:
4741 If this variable is not set, initrd images will be
4742 copied to the highest possible address in RAM; this
4743 is usually what you want since it allows for
4744 maximum initrd size. If for some reason you want to
4745 make sure that the initrd image is loaded below the
4746 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
4747 variable to a value of "no" or "off" or "0".
4748 Alternatively, you can set it to a maximum upper
4749 address to use (U-Boot will still check that it
4750 does not overwrite the U-Boot stack and data).
4752 For instance, when you have a system with 16 MB
4753 RAM, and want to reserve 4 MB from use by Linux,
4754 you can do this by adding "mem=12M" to the value of
4755 the "bootargs" variable. However, now you must make
4756 sure that the initrd image is placed in the first
4757 12 MB as well - this can be done with
4759 setenv initrd_high 00c00000
4761 If you set initrd_high to 0xFFFFFFFF, this is an
4762 indication to U-Boot that all addresses are legal
4763 for the Linux kernel, including addresses in flash
4764 memory. In this case U-Boot will NOT COPY the
4765 ramdisk at all. This may be useful to reduce the
4766 boot time on your system, but requires that this
4767 feature is supported by your Linux kernel.
4769 ipaddr - IP address; needed for tftpboot command
4771 loadaddr - Default load address for commands like "bootp",
4772 "rarpboot", "tftpboot", "loadb" or "diskboot"
4774 loads_echo - see CONFIG_LOADS_ECHO
4776 serverip - TFTP server IP address; needed for tftpboot command
4778 bootretry - see CONFIG_BOOT_RETRY_TIME
4780 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
4782 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
4784 ethprime - controls which interface is used first.
4786 ethact - controls which interface is currently active.
4787 For example you can do the following
4789 => setenv ethact FEC
4790 => ping 192.168.0.1 # traffic sent on FEC
4791 => setenv ethact SCC
4792 => ping 10.0.0.1 # traffic sent on SCC
4794 ethrotate - When set to "no" U-Boot does not go through all
4795 available network interfaces.
4796 It just stays at the currently selected interface.
4798 netretry - When set to "no" each network operation will
4799 either succeed or fail without retrying.
4800 When set to "once" the network operation will
4801 fail when all the available network interfaces
4802 are tried once without success.
4803 Useful on scripts which control the retry operation
4806 npe_ucode - set load address for the NPE microcode
4808 silent_linux - If set then Linux will be told to boot silently, by
4809 changing the console to be empty. If "yes" it will be
4810 made silent. If "no" it will not be made silent. If
4811 unset, then it will be made silent if the U-Boot console
4814 tftpsrcp - If this is set, the value is used for TFTP's
4817 tftpdstp - If this is set, the value is used for TFTP's UDP
4818 destination port instead of the Well Know Port 69.
4820 tftpblocksize - Block size to use for TFTP transfers; if not set,
4821 we use the TFTP server's default block size
4823 tftptimeout - Retransmission timeout for TFTP packets (in milli-
4824 seconds, minimum value is 1000 = 1 second). Defines
4825 when a packet is considered to be lost so it has to
4826 be retransmitted. The default is 5000 = 5 seconds.
4827 Lowering this value may make downloads succeed
4828 faster in networks with high packet loss rates or
4829 with unreliable TFTP servers.
4831 tftptimeoutcountmax - maximum count of TFTP timeouts (no
4832 unit, minimum value = 0). Defines how many timeouts
4833 can happen during a single file transfer before that
4834 transfer is aborted. The default is 10, and 0 means
4835 'no timeouts allowed'. Increasing this value may help
4836 downloads succeed with high packet loss rates, or with
4837 unreliable TFTP servers or client hardware.
4839 vlan - When set to a value < 4095 the traffic over
4840 Ethernet is encapsulated/received over 802.1q
4843 bootpretryperiod - Period during which BOOTP/DHCP sends retries.
4844 Unsigned value, in milliseconds. If not set, the period will
4845 be either the default (28000), or a value based on
4846 CONFIG_NET_RETRY_COUNT, if defined. This value has
4847 precedence over the valu based on CONFIG_NET_RETRY_COUNT.
4849 The following image location variables contain the location of images
4850 used in booting. The "Image" column gives the role of the image and is
4851 not an environment variable name. The other columns are environment
4852 variable names. "File Name" gives the name of the file on a TFTP
4853 server, "RAM Address" gives the location in RAM the image will be
4854 loaded to, and "Flash Location" gives the image's address in NOR
4855 flash or offset in NAND flash.
4857 *Note* - these variables don't have to be defined for all boards, some
4858 boards currently use other variables for these purposes, and some
4859 boards use these variables for other purposes.
4861 Image File Name RAM Address Flash Location
4862 ----- --------- ----------- --------------
4863 u-boot u-boot u-boot_addr_r u-boot_addr
4864 Linux kernel bootfile kernel_addr_r kernel_addr
4865 device tree blob fdtfile fdt_addr_r fdt_addr
4866 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
4868 The following environment variables may be used and automatically
4869 updated by the network boot commands ("bootp" and "rarpboot"),
4870 depending the information provided by your boot server:
4872 bootfile - see above
4873 dnsip - IP address of your Domain Name Server
4874 dnsip2 - IP address of your secondary Domain Name Server
4875 gatewayip - IP address of the Gateway (Router) to use
4876 hostname - Target hostname
4878 netmask - Subnet Mask
4879 rootpath - Pathname of the root filesystem on the NFS server
4880 serverip - see above
4883 There are two special Environment Variables:
4885 serial# - contains hardware identification information such
4886 as type string and/or serial number
4887 ethaddr - Ethernet address
4889 These variables can be set only once (usually during manufacturing of
4890 the board). U-Boot refuses to delete or overwrite these variables
4891 once they have been set once.
4894 Further special Environment Variables:
4896 ver - Contains the U-Boot version string as printed
4897 with the "version" command. This variable is
4898 readonly (see CONFIG_VERSION_VARIABLE).
4901 Please note that changes to some configuration parameters may take
4902 only effect after the next boot (yes, that's just like Windoze :-).
4905 Callback functions for environment variables:
4906 ---------------------------------------------
4908 For some environment variables, the behavior of u-boot needs to change
4909 when their values are changed. This functionality allows functions to
4910 be associated with arbitrary variables. On creation, overwrite, or
4911 deletion, the callback will provide the opportunity for some side
4912 effect to happen or for the change to be rejected.
4914 The callbacks are named and associated with a function using the
4915 U_BOOT_ENV_CALLBACK macro in your board or driver code.
4917 These callbacks are associated with variables in one of two ways. The
4918 static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC
4919 in the board configuration to a string that defines a list of
4920 associations. The list must be in the following format:
4922 entry = variable_name[:callback_name]
4925 If the callback name is not specified, then the callback is deleted.
4926 Spaces are also allowed anywhere in the list.
4928 Callbacks can also be associated by defining the ".callbacks" variable
4929 with the same list format above. Any association in ".callbacks" will
4930 override any association in the static list. You can define
4931 CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the
4932 ".callbacks" environment variable in the default or embedded environment.
4934 If CONFIG_REGEX is defined, the variable_name above is evaluated as a
4935 regular expression. This allows multiple variables to be connected to
4936 the same callback without explicitly listing them all out.
4939 Command Line Parsing:
4940 =====================
4942 There are two different command line parsers available with U-Boot:
4943 the old "simple" one, and the much more powerful "hush" shell:
4945 Old, simple command line parser:
4946 --------------------------------
4948 - supports environment variables (through setenv / saveenv commands)
4949 - several commands on one line, separated by ';'
4950 - variable substitution using "... ${name} ..." syntax
4951 - special characters ('$', ';') can be escaped by prefixing with '\',
4953 setenv bootcmd bootm \${address}
4954 - You can also escape text by enclosing in single apostrophes, for example:
4955 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
4960 - similar to Bourne shell, with control structures like
4961 if...then...else...fi, for...do...done; while...do...done,
4962 until...do...done, ...
4963 - supports environment ("global") variables (through setenv / saveenv
4964 commands) and local shell variables (through standard shell syntax
4965 "name=value"); only environment variables can be used with "run"
4971 (1) If a command line (or an environment variable executed by a "run"
4972 command) contains several commands separated by semicolon, and
4973 one of these commands fails, then the remaining commands will be
4976 (2) If you execute several variables with one call to run (i. e.
4977 calling run with a list of variables as arguments), any failing
4978 command will cause "run" to terminate, i. e. the remaining
4979 variables are not executed.
4981 Note for Redundant Ethernet Interfaces:
4982 =======================================
4984 Some boards come with redundant Ethernet interfaces; U-Boot supports
4985 such configurations and is capable of automatic selection of a
4986 "working" interface when needed. MAC assignment works as follows:
4988 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
4989 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
4990 "eth1addr" (=>eth1), "eth2addr", ...
4992 If the network interface stores some valid MAC address (for instance
4993 in SROM), this is used as default address if there is NO correspon-
4994 ding setting in the environment; if the corresponding environment
4995 variable is set, this overrides the settings in the card; that means:
4997 o If the SROM has a valid MAC address, and there is no address in the
4998 environment, the SROM's address is used.
5000 o If there is no valid address in the SROM, and a definition in the
5001 environment exists, then the value from the environment variable is
5004 o If both the SROM and the environment contain a MAC address, and
5005 both addresses are the same, this MAC address is used.
5007 o If both the SROM and the environment contain a MAC address, and the
5008 addresses differ, the value from the environment is used and a
5011 o If neither SROM nor the environment contain a MAC address, an error
5012 is raised. If CONFIG_NET_RANDOM_ETHADDR is defined, then in this case
5013 a random, locally-assigned MAC is used.
5015 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
5016 will be programmed into hardware as part of the initialization process. This
5017 may be skipped by setting the appropriate 'ethmacskip' environment variable.
5018 The naming convention is as follows:
5019 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
5024 U-Boot is capable of booting (and performing other auxiliary operations on)
5025 images in two formats:
5027 New uImage format (FIT)
5028 -----------------------
5030 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
5031 to Flattened Device Tree). It allows the use of images with multiple
5032 components (several kernels, ramdisks, etc.), with contents protected by
5033 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
5039 Old image format is based on binary files which can be basically anything,
5040 preceded by a special header; see the definitions in include/image.h for
5041 details; basically, the header defines the following image properties:
5043 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
5044 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
5045 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
5046 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
5048 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
5049 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
5050 Currently supported: ARM, AVR32, Intel x86, MIPS, NDS32, Nios II, PowerPC).
5051 * Compression Type (uncompressed, gzip, bzip2)
5057 The header is marked by a special Magic Number, and both the header
5058 and the data portions of the image are secured against corruption by
5065 Although U-Boot should support any OS or standalone application
5066 easily, the main focus has always been on Linux during the design of
5069 U-Boot includes many features that so far have been part of some
5070 special "boot loader" code within the Linux kernel. Also, any
5071 "initrd" images to be used are no longer part of one big Linux image;
5072 instead, kernel and "initrd" are separate images. This implementation
5073 serves several purposes:
5075 - the same features can be used for other OS or standalone
5076 applications (for instance: using compressed images to reduce the
5077 Flash memory footprint)
5079 - it becomes much easier to port new Linux kernel versions because
5080 lots of low-level, hardware dependent stuff are done by U-Boot
5082 - the same Linux kernel image can now be used with different "initrd"
5083 images; of course this also means that different kernel images can
5084 be run with the same "initrd". This makes testing easier (you don't
5085 have to build a new "zImage.initrd" Linux image when you just
5086 change a file in your "initrd"). Also, a field-upgrade of the
5087 software is easier now.
5093 Porting Linux to U-Boot based systems:
5094 ---------------------------------------
5096 U-Boot cannot save you from doing all the necessary modifications to
5097 configure the Linux device drivers for use with your target hardware
5098 (no, we don't intend to provide a full virtual machine interface to
5101 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
5103 Just make sure your machine specific header file (for instance
5104 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
5105 Information structure as we define in include/asm-<arch>/u-boot.h,
5106 and make sure that your definition of IMAP_ADDR uses the same value
5107 as your U-Boot configuration in CONFIG_SYS_IMMR.
5109 Note that U-Boot now has a driver model, a unified model for drivers.
5110 If you are adding a new driver, plumb it into driver model. If there
5111 is no uclass available, you are encouraged to create one. See
5115 Configuring the Linux kernel:
5116 -----------------------------
5118 No specific requirements for U-Boot. Make sure you have some root
5119 device (initial ramdisk, NFS) for your target system.
5122 Building a Linux Image:
5123 -----------------------
5125 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
5126 not used. If you use recent kernel source, a new build target
5127 "uImage" will exist which automatically builds an image usable by
5128 U-Boot. Most older kernels also have support for a "pImage" target,
5129 which was introduced for our predecessor project PPCBoot and uses a
5130 100% compatible format.
5134 make TQM850L_defconfig
5139 The "uImage" build target uses a special tool (in 'tools/mkimage') to
5140 encapsulate a compressed Linux kernel image with header information,
5141 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
5143 * build a standard "vmlinux" kernel image (in ELF binary format):
5145 * convert the kernel into a raw binary image:
5147 ${CROSS_COMPILE}-objcopy -O binary \
5148 -R .note -R .comment \
5149 -S vmlinux linux.bin
5151 * compress the binary image:
5155 * package compressed binary image for U-Boot:
5157 mkimage -A ppc -O linux -T kernel -C gzip \
5158 -a 0 -e 0 -n "Linux Kernel Image" \
5159 -d linux.bin.gz uImage
5162 The "mkimage" tool can also be used to create ramdisk images for use
5163 with U-Boot, either separated from the Linux kernel image, or
5164 combined into one file. "mkimage" encapsulates the images with a 64
5165 byte header containing information about target architecture,
5166 operating system, image type, compression method, entry points, time
5167 stamp, CRC32 checksums, etc.
5169 "mkimage" can be called in two ways: to verify existing images and
5170 print the header information, or to build new images.
5172 In the first form (with "-l" option) mkimage lists the information
5173 contained in the header of an existing U-Boot image; this includes
5174 checksum verification:
5176 tools/mkimage -l image
5177 -l ==> list image header information
5179 The second form (with "-d" option) is used to build a U-Boot image
5180 from a "data file" which is used as image payload:
5182 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
5183 -n name -d data_file image
5184 -A ==> set architecture to 'arch'
5185 -O ==> set operating system to 'os'
5186 -T ==> set image type to 'type'
5187 -C ==> set compression type 'comp'
5188 -a ==> set load address to 'addr' (hex)
5189 -e ==> set entry point to 'ep' (hex)
5190 -n ==> set image name to 'name'
5191 -d ==> use image data from 'datafile'
5193 Right now, all Linux kernels for PowerPC systems use the same load
5194 address (0x00000000), but the entry point address depends on the
5197 - 2.2.x kernels have the entry point at 0x0000000C,
5198 - 2.3.x and later kernels have the entry point at 0x00000000.
5200 So a typical call to build a U-Boot image would read:
5202 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5203 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
5204 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
5205 > examples/uImage.TQM850L
5206 Image Name: 2.4.4 kernel for TQM850L
5207 Created: Wed Jul 19 02:34:59 2000
5208 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5209 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5210 Load Address: 0x00000000
5211 Entry Point: 0x00000000
5213 To verify the contents of the image (or check for corruption):
5215 -> tools/mkimage -l examples/uImage.TQM850L
5216 Image Name: 2.4.4 kernel for TQM850L
5217 Created: Wed Jul 19 02:34:59 2000
5218 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5219 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5220 Load Address: 0x00000000
5221 Entry Point: 0x00000000
5223 NOTE: for embedded systems where boot time is critical you can trade
5224 speed for memory and install an UNCOMPRESSED image instead: this
5225 needs more space in Flash, but boots much faster since it does not
5226 need to be uncompressed:
5228 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
5229 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5230 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
5231 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
5232 > examples/uImage.TQM850L-uncompressed
5233 Image Name: 2.4.4 kernel for TQM850L
5234 Created: Wed Jul 19 02:34:59 2000
5235 Image Type: PowerPC Linux Kernel Image (uncompressed)
5236 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
5237 Load Address: 0x00000000
5238 Entry Point: 0x00000000
5241 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
5242 when your kernel is intended to use an initial ramdisk:
5244 -> tools/mkimage -n 'Simple Ramdisk Image' \
5245 > -A ppc -O linux -T ramdisk -C gzip \
5246 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
5247 Image Name: Simple Ramdisk Image
5248 Created: Wed Jan 12 14:01:50 2000
5249 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5250 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
5251 Load Address: 0x00000000
5252 Entry Point: 0x00000000
5254 The "dumpimage" is a tool to disassemble images built by mkimage. Its "-i"
5255 option performs the converse operation of the mkimage's second form (the "-d"
5256 option). Given an image built by mkimage, the dumpimage extracts a "data file"
5259 tools/dumpimage -i image -T type -p position data_file
5260 -i ==> extract from the 'image' a specific 'data_file'
5261 -T ==> set image type to 'type'
5262 -p ==> 'position' (starting at 0) of the 'data_file' inside the 'image'
5265 Installing a Linux Image:
5266 -------------------------
5268 To downloading a U-Boot image over the serial (console) interface,
5269 you must convert the image to S-Record format:
5271 objcopy -I binary -O srec examples/image examples/image.srec
5273 The 'objcopy' does not understand the information in the U-Boot
5274 image header, so the resulting S-Record file will be relative to
5275 address 0x00000000. To load it to a given address, you need to
5276 specify the target address as 'offset' parameter with the 'loads'
5279 Example: install the image to address 0x40100000 (which on the
5280 TQM8xxL is in the first Flash bank):
5282 => erase 40100000 401FFFFF
5288 ## Ready for S-Record download ...
5289 ~>examples/image.srec
5290 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
5292 15989 15990 15991 15992
5293 [file transfer complete]
5295 ## Start Addr = 0x00000000
5298 You can check the success of the download using the 'iminfo' command;
5299 this includes a checksum verification so you can be sure no data
5300 corruption happened:
5304 ## Checking Image at 40100000 ...
5305 Image Name: 2.2.13 for initrd on TQM850L
5306 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5307 Data Size: 335725 Bytes = 327 kB = 0 MB
5308 Load Address: 00000000
5309 Entry Point: 0000000c
5310 Verifying Checksum ... OK
5316 The "bootm" command is used to boot an application that is stored in
5317 memory (RAM or Flash). In case of a Linux kernel image, the contents
5318 of the "bootargs" environment variable is passed to the kernel as
5319 parameters. You can check and modify this variable using the
5320 "printenv" and "setenv" commands:
5323 => printenv bootargs
5324 bootargs=root=/dev/ram
5326 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5328 => printenv bootargs
5329 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5332 ## Booting Linux kernel at 40020000 ...
5333 Image Name: 2.2.13 for NFS on TQM850L
5334 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5335 Data Size: 381681 Bytes = 372 kB = 0 MB
5336 Load Address: 00000000
5337 Entry Point: 0000000c
5338 Verifying Checksum ... OK
5339 Uncompressing Kernel Image ... OK
5340 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
5341 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5342 time_init: decrementer frequency = 187500000/60
5343 Calibrating delay loop... 49.77 BogoMIPS
5344 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
5347 If you want to boot a Linux kernel with initial RAM disk, you pass
5348 the memory addresses of both the kernel and the initrd image (PPBCOOT
5349 format!) to the "bootm" command:
5351 => imi 40100000 40200000
5353 ## Checking Image at 40100000 ...
5354 Image Name: 2.2.13 for initrd on TQM850L
5355 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5356 Data Size: 335725 Bytes = 327 kB = 0 MB
5357 Load Address: 00000000
5358 Entry Point: 0000000c
5359 Verifying Checksum ... OK
5361 ## Checking Image at 40200000 ...
5362 Image Name: Simple Ramdisk Image
5363 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5364 Data Size: 566530 Bytes = 553 kB = 0 MB
5365 Load Address: 00000000
5366 Entry Point: 00000000
5367 Verifying Checksum ... OK
5369 => bootm 40100000 40200000
5370 ## Booting Linux kernel at 40100000 ...
5371 Image Name: 2.2.13 for initrd on TQM850L
5372 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5373 Data Size: 335725 Bytes = 327 kB = 0 MB
5374 Load Address: 00000000
5375 Entry Point: 0000000c
5376 Verifying Checksum ... OK
5377 Uncompressing Kernel Image ... OK
5378 ## Loading RAMDisk Image at 40200000 ...
5379 Image Name: Simple Ramdisk Image
5380 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5381 Data Size: 566530 Bytes = 553 kB = 0 MB
5382 Load Address: 00000000
5383 Entry Point: 00000000
5384 Verifying Checksum ... OK
5385 Loading Ramdisk ... OK
5386 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
5387 Boot arguments: root=/dev/ram
5388 time_init: decrementer frequency = 187500000/60
5389 Calibrating delay loop... 49.77 BogoMIPS
5391 RAMDISK: Compressed image found at block 0
5392 VFS: Mounted root (ext2 filesystem).
5396 Boot Linux and pass a flat device tree:
5399 First, U-Boot must be compiled with the appropriate defines. See the section
5400 titled "Linux Kernel Interface" above for a more in depth explanation. The
5401 following is an example of how to start a kernel and pass an updated
5407 oft=oftrees/mpc8540ads.dtb
5408 => tftp $oftaddr $oft
5409 Speed: 1000, full duplex
5411 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
5412 Filename 'oftrees/mpc8540ads.dtb'.
5413 Load address: 0x300000
5416 Bytes transferred = 4106 (100a hex)
5417 => tftp $loadaddr $bootfile
5418 Speed: 1000, full duplex
5420 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
5422 Load address: 0x200000
5423 Loading:############
5425 Bytes transferred = 1029407 (fb51f hex)
5430 => bootm $loadaddr - $oftaddr
5431 ## Booting image at 00200000 ...
5432 Image Name: Linux-2.6.17-dirty
5433 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5434 Data Size: 1029343 Bytes = 1005.2 kB
5435 Load Address: 00000000
5436 Entry Point: 00000000
5437 Verifying Checksum ... OK
5438 Uncompressing Kernel Image ... OK
5439 Booting using flat device tree at 0x300000
5440 Using MPC85xx ADS machine description
5441 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
5445 More About U-Boot Image Types:
5446 ------------------------------
5448 U-Boot supports the following image types:
5450 "Standalone Programs" are directly runnable in the environment
5451 provided by U-Boot; it is expected that (if they behave
5452 well) you can continue to work in U-Boot after return from
5453 the Standalone Program.
5454 "OS Kernel Images" are usually images of some Embedded OS which
5455 will take over control completely. Usually these programs
5456 will install their own set of exception handlers, device
5457 drivers, set up the MMU, etc. - this means, that you cannot
5458 expect to re-enter U-Boot except by resetting the CPU.
5459 "RAMDisk Images" are more or less just data blocks, and their
5460 parameters (address, size) are passed to an OS kernel that is
5462 "Multi-File Images" contain several images, typically an OS
5463 (Linux) kernel image and one or more data images like
5464 RAMDisks. This construct is useful for instance when you want
5465 to boot over the network using BOOTP etc., where the boot
5466 server provides just a single image file, but you want to get
5467 for instance an OS kernel and a RAMDisk image.
5469 "Multi-File Images" start with a list of image sizes, each
5470 image size (in bytes) specified by an "uint32_t" in network
5471 byte order. This list is terminated by an "(uint32_t)0".
5472 Immediately after the terminating 0 follow the images, one by
5473 one, all aligned on "uint32_t" boundaries (size rounded up to
5474 a multiple of 4 bytes).
5476 "Firmware Images" are binary images containing firmware (like
5477 U-Boot or FPGA images) which usually will be programmed to
5480 "Script files" are command sequences that will be executed by
5481 U-Boot's command interpreter; this feature is especially
5482 useful when you configure U-Boot to use a real shell (hush)
5483 as command interpreter.
5485 Booting the Linux zImage:
5486 -------------------------
5488 On some platforms, it's possible to boot Linux zImage. This is done
5489 using the "bootz" command. The syntax of "bootz" command is the same
5490 as the syntax of "bootm" command.
5492 Note, defining the CONFIG_SUPPORT_RAW_INITRD allows user to supply
5493 kernel with raw initrd images. The syntax is slightly different, the
5494 address of the initrd must be augmented by it's size, in the following
5495 format: "<initrd addres>:<initrd size>".
5501 One of the features of U-Boot is that you can dynamically load and
5502 run "standalone" applications, which can use some resources of
5503 U-Boot like console I/O functions or interrupt services.
5505 Two simple examples are included with the sources:
5510 'examples/hello_world.c' contains a small "Hello World" Demo
5511 application; it is automatically compiled when you build U-Boot.
5512 It's configured to run at address 0x00040004, so you can play with it
5516 ## Ready for S-Record download ...
5517 ~>examples/hello_world.srec
5518 1 2 3 4 5 6 7 8 9 10 11 ...
5519 [file transfer complete]
5521 ## Start Addr = 0x00040004
5523 => go 40004 Hello World! This is a test.
5524 ## Starting application at 0x00040004 ...
5535 Hit any key to exit ...
5537 ## Application terminated, rc = 0x0
5539 Another example, which demonstrates how to register a CPM interrupt
5540 handler with the U-Boot code, can be found in 'examples/timer.c'.
5541 Here, a CPM timer is set up to generate an interrupt every second.
5542 The interrupt service routine is trivial, just printing a '.'
5543 character, but this is just a demo program. The application can be
5544 controlled by the following keys:
5546 ? - print current values og the CPM Timer registers
5547 b - enable interrupts and start timer
5548 e - stop timer and disable interrupts
5549 q - quit application
5552 ## Ready for S-Record download ...
5553 ~>examples/timer.srec
5554 1 2 3 4 5 6 7 8 9 10 11 ...
5555 [file transfer complete]
5557 ## Start Addr = 0x00040004
5560 ## Starting application at 0x00040004 ...
5563 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
5566 [q, b, e, ?] Set interval 1000000 us
5569 [q, b, e, ?] ........
5570 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
5573 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
5576 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
5579 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
5581 [q, b, e, ?] ...Stopping timer
5583 [q, b, e, ?] ## Application terminated, rc = 0x0
5589 Over time, many people have reported problems when trying to use the
5590 "minicom" terminal emulation program for serial download. I (wd)
5591 consider minicom to be broken, and recommend not to use it. Under
5592 Unix, I recommend to use C-Kermit for general purpose use (and
5593 especially for kermit binary protocol download ("loadb" command), and
5594 use "cu" for S-Record download ("loads" command). See
5595 http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
5596 for help with kermit.
5599 Nevertheless, if you absolutely want to use it try adding this
5600 configuration to your "File transfer protocols" section:
5602 Name Program Name U/D FullScr IO-Red. Multi
5603 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
5604 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
5610 Starting at version 0.9.2, U-Boot supports NetBSD both as host
5611 (build U-Boot) and target system (boots NetBSD/mpc8xx).
5613 Building requires a cross environment; it is known to work on
5614 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
5615 need gmake since the Makefiles are not compatible with BSD make).
5616 Note that the cross-powerpc package does not install include files;
5617 attempting to build U-Boot will fail because <machine/ansi.h> is
5618 missing. This file has to be installed and patched manually:
5620 # cd /usr/pkg/cross/powerpc-netbsd/include
5622 # ln -s powerpc machine
5623 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
5624 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
5626 Native builds *don't* work due to incompatibilities between native
5627 and U-Boot include files.
5629 Booting assumes that (the first part of) the image booted is a
5630 stage-2 loader which in turn loads and then invokes the kernel
5631 proper. Loader sources will eventually appear in the NetBSD source
5632 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
5633 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
5636 Implementation Internals:
5637 =========================
5639 The following is not intended to be a complete description of every
5640 implementation detail. However, it should help to understand the
5641 inner workings of U-Boot and make it easier to port it to custom
5645 Initial Stack, Global Data:
5646 ---------------------------
5648 The implementation of U-Boot is complicated by the fact that U-Boot
5649 starts running out of ROM (flash memory), usually without access to
5650 system RAM (because the memory controller is not initialized yet).
5651 This means that we don't have writable Data or BSS segments, and BSS
5652 is not initialized as zero. To be able to get a C environment working
5653 at all, we have to allocate at least a minimal stack. Implementation
5654 options for this are defined and restricted by the CPU used: Some CPU
5655 models provide on-chip memory (like the IMMR area on MPC8xx and
5656 MPC826x processors), on others (parts of) the data cache can be
5657 locked as (mis-) used as memory, etc.
5659 Chris Hallinan posted a good summary of these issues to the
5660 U-Boot mailing list:
5662 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
5663 From: "Chris Hallinan" <clh@net1plus.com>
5664 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
5667 Correct me if I'm wrong, folks, but the way I understand it
5668 is this: Using DCACHE as initial RAM for Stack, etc, does not
5669 require any physical RAM backing up the cache. The cleverness
5670 is that the cache is being used as a temporary supply of
5671 necessary storage before the SDRAM controller is setup. It's
5672 beyond the scope of this list to explain the details, but you
5673 can see how this works by studying the cache architecture and
5674 operation in the architecture and processor-specific manuals.
5676 OCM is On Chip Memory, which I believe the 405GP has 4K. It
5677 is another option for the system designer to use as an
5678 initial stack/RAM area prior to SDRAM being available. Either
5679 option should work for you. Using CS 4 should be fine if your
5680 board designers haven't used it for something that would
5681 cause you grief during the initial boot! It is frequently not
5684 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
5685 with your processor/board/system design. The default value
5686 you will find in any recent u-boot distribution in
5687 walnut.h should work for you. I'd set it to a value larger
5688 than your SDRAM module. If you have a 64MB SDRAM module, set
5689 it above 400_0000. Just make sure your board has no resources
5690 that are supposed to respond to that address! That code in
5691 start.S has been around a while and should work as is when
5692 you get the config right.
5697 It is essential to remember this, since it has some impact on the C
5698 code for the initialization procedures:
5700 * Initialized global data (data segment) is read-only. Do not attempt
5703 * Do not use any uninitialized global data (or implicitly initialized
5704 as zero data - BSS segment) at all - this is undefined, initiali-
5705 zation is performed later (when relocating to RAM).
5707 * Stack space is very limited. Avoid big data buffers or things like
5710 Having only the stack as writable memory limits means we cannot use
5711 normal global data to share information between the code. But it
5712 turned out that the implementation of U-Boot can be greatly
5713 simplified by making a global data structure (gd_t) available to all
5714 functions. We could pass a pointer to this data as argument to _all_
5715 functions, but this would bloat the code. Instead we use a feature of
5716 the GCC compiler (Global Register Variables) to share the data: we
5717 place a pointer (gd) to the global data into a register which we
5718 reserve for this purpose.
5720 When choosing a register for such a purpose we are restricted by the
5721 relevant (E)ABI specifications for the current architecture, and by
5722 GCC's implementation.
5724 For PowerPC, the following registers have specific use:
5726 R2: reserved for system use
5727 R3-R4: parameter passing and return values
5728 R5-R10: parameter passing
5729 R13: small data area pointer
5733 (U-Boot also uses R12 as internal GOT pointer. r12
5734 is a volatile register so r12 needs to be reset when
5735 going back and forth between asm and C)
5737 ==> U-Boot will use R2 to hold a pointer to the global data
5739 Note: on PPC, we could use a static initializer (since the
5740 address of the global data structure is known at compile time),
5741 but it turned out that reserving a register results in somewhat
5742 smaller code - although the code savings are not that big (on
5743 average for all boards 752 bytes for the whole U-Boot image,
5744 624 text + 127 data).
5746 On ARM, the following registers are used:
5748 R0: function argument word/integer result
5749 R1-R3: function argument word
5750 R9: platform specific
5751 R10: stack limit (used only if stack checking is enabled)
5752 R11: argument (frame) pointer
5753 R12: temporary workspace
5756 R15: program counter
5758 ==> U-Boot will use R9 to hold a pointer to the global data
5760 Note: on ARM, only R_ARM_RELATIVE relocations are supported.
5762 On Nios II, the ABI is documented here:
5763 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
5765 ==> U-Boot will use gp to hold a pointer to the global data
5767 Note: on Nios II, we give "-G0" option to gcc and don't use gp
5768 to access small data sections, so gp is free.
5770 On NDS32, the following registers are used:
5772 R0-R1: argument/return
5774 R15: temporary register for assembler
5775 R16: trampoline register
5776 R28: frame pointer (FP)
5777 R29: global pointer (GP)
5778 R30: link register (LP)
5779 R31: stack pointer (SP)
5780 PC: program counter (PC)
5782 ==> U-Boot will use R10 to hold a pointer to the global data
5784 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
5785 or current versions of GCC may "optimize" the code too much.
5790 U-Boot runs in system state and uses physical addresses, i.e. the
5791 MMU is not used either for address mapping nor for memory protection.
5793 The available memory is mapped to fixed addresses using the memory
5794 controller. In this process, a contiguous block is formed for each
5795 memory type (Flash, SDRAM, SRAM), even when it consists of several
5796 physical memory banks.
5798 U-Boot is installed in the first 128 kB of the first Flash bank (on
5799 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
5800 booting and sizing and initializing DRAM, the code relocates itself
5801 to the upper end of DRAM. Immediately below the U-Boot code some
5802 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
5803 configuration setting]. Below that, a structure with global Board
5804 Info data is placed, followed by the stack (growing downward).
5806 Additionally, some exception handler code is copied to the low 8 kB
5807 of DRAM (0x00000000 ... 0x00001FFF).
5809 So a typical memory configuration with 16 MB of DRAM could look like
5812 0x0000 0000 Exception Vector code
5815 0x0000 2000 Free for Application Use
5821 0x00FB FF20 Monitor Stack (Growing downward)
5822 0x00FB FFAC Board Info Data and permanent copy of global data
5823 0x00FC 0000 Malloc Arena
5826 0x00FE 0000 RAM Copy of Monitor Code
5827 ... eventually: LCD or video framebuffer
5828 ... eventually: pRAM (Protected RAM - unchanged by reset)
5829 0x00FF FFFF [End of RAM]
5832 System Initialization:
5833 ----------------------
5835 In the reset configuration, U-Boot starts at the reset entry point
5836 (on most PowerPC systems at address 0x00000100). Because of the reset
5837 configuration for CS0# this is a mirror of the on board Flash memory.
5838 To be able to re-map memory U-Boot then jumps to its link address.
5839 To be able to implement the initialization code in C, a (small!)
5840 initial stack is set up in the internal Dual Ported RAM (in case CPUs
5841 which provide such a feature like MPC8xx or MPC8260), or in a locked
5842 part of the data cache. After that, U-Boot initializes the CPU core,
5843 the caches and the SIU.
5845 Next, all (potentially) available memory banks are mapped using a
5846 preliminary mapping. For example, we put them on 512 MB boundaries
5847 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
5848 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
5849 programmed for SDRAM access. Using the temporary configuration, a
5850 simple memory test is run that determines the size of the SDRAM
5853 When there is more than one SDRAM bank, and the banks are of
5854 different size, the largest is mapped first. For equal size, the first
5855 bank (CS2#) is mapped first. The first mapping is always for address
5856 0x00000000, with any additional banks following immediately to create
5857 contiguous memory starting from 0.
5859 Then, the monitor installs itself at the upper end of the SDRAM area
5860 and allocates memory for use by malloc() and for the global Board
5861 Info data; also, the exception vector code is copied to the low RAM
5862 pages, and the final stack is set up.
5864 Only after this relocation will you have a "normal" C environment;
5865 until that you are restricted in several ways, mostly because you are
5866 running from ROM, and because the code will have to be relocated to a
5870 U-Boot Porting Guide:
5871 ----------------------
5873 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
5877 int main(int argc, char *argv[])
5879 sighandler_t no_more_time;
5881 signal(SIGALRM, no_more_time);
5882 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
5884 if (available_money > available_manpower) {
5885 Pay consultant to port U-Boot;
5889 Download latest U-Boot source;
5891 Subscribe to u-boot mailing list;
5894 email("Hi, I am new to U-Boot, how do I get started?");
5897 Read the README file in the top level directory;
5898 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
5899 Read applicable doc/*.README;
5900 Read the source, Luke;
5901 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
5904 if (available_money > toLocalCurrency ($2500))
5907 Add a lot of aggravation and time;
5909 if (a similar board exists) { /* hopefully... */
5910 cp -a board/<similar> board/<myboard>
5911 cp include/configs/<similar>.h include/configs/<myboard>.h
5913 Create your own board support subdirectory;
5914 Create your own board include/configs/<myboard>.h file;
5916 Edit new board/<myboard> files
5917 Edit new include/configs/<myboard>.h
5922 Add / modify source code;
5926 email("Hi, I am having problems...");
5928 Send patch file to the U-Boot email list;
5929 if (reasonable critiques)
5930 Incorporate improvements from email list code review;
5932 Defend code as written;
5938 void no_more_time (int sig)
5947 All contributions to U-Boot should conform to the Linux kernel
5948 coding style; see the file "Documentation/CodingStyle" and the script
5949 "scripts/Lindent" in your Linux kernel source directory.
5951 Source files originating from a different project (for example the
5952 MTD subsystem) are generally exempt from these guidelines and are not
5953 reformatted to ease subsequent migration to newer versions of those
5956 Please note that U-Boot is implemented in C (and to some small parts in
5957 Assembler); no C++ is used, so please do not use C++ style comments (//)
5960 Please also stick to the following formatting rules:
5961 - remove any trailing white space
5962 - use TAB characters for indentation and vertical alignment, not spaces
5963 - make sure NOT to use DOS '\r\n' line feeds
5964 - do not add more than 2 consecutive empty lines to source files
5965 - do not add trailing empty lines to source files
5967 Submissions which do not conform to the standards may be returned
5968 with a request to reformat the changes.
5974 Since the number of patches for U-Boot is growing, we need to
5975 establish some rules. Submissions which do not conform to these rules
5976 may be rejected, even when they contain important and valuable stuff.
5978 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
5980 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
5981 see http://lists.denx.de/mailman/listinfo/u-boot
5983 When you send a patch, please include the following information with
5986 * For bug fixes: a description of the bug and how your patch fixes
5987 this bug. Please try to include a way of demonstrating that the
5988 patch actually fixes something.
5990 * For new features: a description of the feature and your
5993 * A CHANGELOG entry as plaintext (separate from the patch)
5995 * For major contributions, add a MAINTAINERS file with your
5996 information and associated file and directory references.
5998 * When you add support for a new board, don't forget to add a
5999 maintainer e-mail address to the boards.cfg file, too.
6001 * If your patch adds new configuration options, don't forget to
6002 document these in the README file.
6004 * The patch itself. If you are using git (which is *strongly*
6005 recommended) you can easily generate the patch using the
6006 "git format-patch". If you then use "git send-email" to send it to
6007 the U-Boot mailing list, you will avoid most of the common problems
6008 with some other mail clients.
6010 If you cannot use git, use "diff -purN OLD NEW". If your version of
6011 diff does not support these options, then get the latest version of
6014 The current directory when running this command shall be the parent
6015 directory of the U-Boot source tree (i. e. please make sure that
6016 your patch includes sufficient directory information for the
6019 We prefer patches as plain text. MIME attachments are discouraged,
6020 and compressed attachments must not be used.
6022 * If one logical set of modifications affects or creates several
6023 files, all these changes shall be submitted in a SINGLE patch file.
6025 * Changesets that contain different, unrelated modifications shall be
6026 submitted as SEPARATE patches, one patch per changeset.
6031 * Before sending the patch, run the buildman script on your patched
6032 source tree and make sure that no errors or warnings are reported
6033 for any of the boards.
6035 * Keep your modifications to the necessary minimum: A patch
6036 containing several unrelated changes or arbitrary reformats will be
6037 returned with a request to re-formatting / split it.
6039 * If you modify existing code, make sure that your new code does not
6040 add to the memory footprint of the code ;-) Small is beautiful!
6041 When adding new features, these should compile conditionally only
6042 (using #ifdef), and the resulting code with the new feature
6043 disabled must not need more memory than the old code without your
6046 * Remember that there is a size limit of 100 kB per message on the
6047 u-boot mailing list. Bigger patches will be moderated. If they are
6048 reasonable and not too big, they will be acknowledged. But patches
6049 bigger than the size limit should be avoided.
projects / platform / kernel / u-boot.git / blob