2 # (C) Copyright 2000 - 2013
3 # Wolfgang Denk, DENX Software Engineering, wd@denx.de.
5 # SPDX-License-Identifier: GPL-2.0+
11 This directory contains the source code for U-Boot, a boot loader for
12 Embedded boards based on PowerPC, ARM, MIPS and several other
13 processors, which can be installed in a boot ROM and used to
14 initialize and test the hardware or to download and run application
17 The development of U-Boot is closely related to Linux: some parts of
18 the source code originate in the Linux source tree, we have some
19 header files in common, and special provision has been made to
20 support booting of Linux images.
22 Some attention has been paid to make this software easily
23 configurable and extendable. For instance, all monitor commands are
24 implemented with the same call interface, so that it's very easy to
25 add new commands. Also, instead of permanently adding rarely used
26 code (for instance hardware test utilities) to the monitor, you can
27 load and run it dynamically.
33 In general, all boards for which a configuration option exists in the
34 Makefile have been tested to some extent and can be considered
35 "working". In fact, many of them are used in production systems.
37 In case of problems see the CHANGELOG file to find out who contributed
38 the specific port. In addition, there are various MAINTAINERS files
39 scattered throughout the U-Boot source identifying the people or
40 companies responsible for various boards and subsystems.
42 Note: As of August, 2010, there is no longer a CHANGELOG file in the
43 actual U-Boot source tree; however, it can be created dynamically
44 from the Git log using:
52 In case you have questions about, problems with or contributions for
53 U-Boot, you should send a message to the U-Boot mailing list at
54 <u-boot@lists.denx.de>. There is also an archive of previous traffic
55 on the mailing list - please search the archive before asking FAQ's.
56 Please see http://lists.denx.de/pipermail/u-boot and
57 http://dir.gmane.org/gmane.comp.boot-loaders.u-boot
60 Where to get source code:
61 =========================
63 The U-Boot source code is maintained in the Git repository at
64 git://www.denx.de/git/u-boot.git ; you can browse it online at
65 http://www.denx.de/cgi-bin/gitweb.cgi?p=u-boot.git;a=summary
67 The "snapshot" links on this page allow you to download tarballs of
68 any version you might be interested in. Official releases are also
69 available for FTP download from the ftp://ftp.denx.de/pub/u-boot/
72 Pre-built (and tested) images are available from
73 ftp://ftp.denx.de/pub/u-boot/images/
79 - start from 8xxrom sources
80 - create PPCBoot project (http://sourceforge.net/projects/ppcboot)
82 - make it easier to add custom boards
83 - make it possible to add other [PowerPC] CPUs
84 - extend functions, especially:
85 * Provide extended interface to Linux boot loader
88 * PCMCIA / CompactFlash / ATA disk / SCSI ... boot
89 - create ARMBoot project (http://sourceforge.net/projects/armboot)
90 - add other CPU families (starting with ARM)
91 - create U-Boot project (http://sourceforge.net/projects/u-boot)
92 - current project page: see http://www.denx.de/wiki/U-Boot
98 The "official" name of this project is "Das U-Boot". The spelling
99 "U-Boot" shall be used in all written text (documentation, comments
100 in source files etc.). Example:
102 This is the README file for the U-Boot project.
104 File names etc. shall be based on the string "u-boot". Examples:
106 include/asm-ppc/u-boot.h
108 #include <asm/u-boot.h>
110 Variable names, preprocessor constants etc. shall be either based on
111 the string "u_boot" or on "U_BOOT". Example:
113 U_BOOT_VERSION u_boot_logo
114 IH_OS_U_BOOT u_boot_hush_start
120 Starting with the release in October 2008, the names of the releases
121 were changed from numerical release numbers without deeper meaning
122 into a time stamp based numbering. Regular releases are identified by
123 names consisting of the calendar year and month of the release date.
124 Additional fields (if present) indicate release candidates or bug fix
125 releases in "stable" maintenance trees.
128 U-Boot v2009.11 - Release November 2009
129 U-Boot v2009.11.1 - Release 1 in version November 2009 stable tree
130 U-Boot v2010.09-rc1 - Release candidate 1 for September 2010 release
136 /arch Architecture specific files
137 /arc Files generic to ARC architecture
138 /arm Files generic to ARM architecture
139 /avr32 Files generic to AVR32 architecture
140 /m68k Files generic to m68k architecture
141 /microblaze Files generic to microblaze architecture
142 /mips Files generic to MIPS architecture
143 /nds32 Files generic to NDS32 architecture
144 /nios2 Files generic to Altera NIOS2 architecture
145 /openrisc Files generic to OpenRISC architecture
146 /powerpc Files generic to PowerPC architecture
147 /sandbox Files generic to HW-independent "sandbox"
148 /sh Files generic to SH architecture
149 /x86 Files generic to x86 architecture
150 /api Machine/arch independent API for external apps
151 /board Board dependent files
152 /cmd U-Boot commands functions
153 /common Misc architecture independent functions
154 /configs Board default configuration files
155 /disk Code for disk drive partition handling
156 /doc Documentation (don't expect too much)
157 /drivers Commonly used device drivers
158 /dts Contains Makefile for building internal U-Boot fdt.
159 /examples Example code for standalone applications, etc.
160 /fs Filesystem code (cramfs, ext2, jffs2, etc.)
161 /include Header Files
162 /lib Library routines generic to all architectures
163 /Licenses Various license files
165 /post Power On Self Test
166 /scripts Various build scripts and Makefiles
167 /test Various unit test files
168 /tools Tools to build S-Record or U-Boot images, etc.
170 Software Configuration:
171 =======================
173 Configuration is usually done using C preprocessor defines; the
174 rationale behind that is to avoid dead code whenever possible.
176 There are two classes of configuration variables:
178 * Configuration _OPTIONS_:
179 These are selectable by the user and have names beginning with
182 * Configuration _SETTINGS_:
183 These depend on the hardware etc. and should not be meddled with if
184 you don't know what you're doing; they have names beginning with
187 Previously, all configuration was done by hand, which involved creating
188 symbolic links and editing configuration files manually. More recently,
189 U-Boot has added the Kbuild infrastructure used by the Linux kernel,
190 allowing you to use the "make menuconfig" command to configure your
194 Selection of Processor Architecture and Board Type:
195 ---------------------------------------------------
197 For all supported boards there are ready-to-use default
198 configurations available; just type "make <board_name>_defconfig".
200 Example: For a TQM823L module type:
203 make TQM823L_defconfig
205 Note: If you're looking for the default configuration file for a board
206 you're sure used to be there but is now missing, check the file
207 doc/README.scrapyard for a list of no longer supported boards.
212 U-Boot can be built natively to run on a Linux host using the 'sandbox'
213 board. This allows feature development which is not board- or architecture-
214 specific to be undertaken on a native platform. The sandbox is also used to
215 run some of U-Boot's tests.
217 See board/sandbox/README.sandbox for more details.
220 Board Initialisation Flow:
221 --------------------------
223 This is the intended start-up flow for boards. This should apply for both
224 SPL and U-Boot proper (i.e. they both follow the same rules).
226 Note: "SPL" stands for "Secondary Program Loader," which is explained in
227 more detail later in this file.
229 At present, SPL mostly uses a separate code path, but the function names
230 and roles of each function are the same. Some boards or architectures
231 may not conform to this. At least most ARM boards which use
232 CONFIG_SPL_FRAMEWORK conform to this.
234 Execution typically starts with an architecture-specific (and possibly
235 CPU-specific) start.S file, such as:
237 - arch/arm/cpu/armv7/start.S
238 - arch/powerpc/cpu/mpc83xx/start.S
239 - arch/mips/cpu/start.S
241 and so on. From there, three functions are called; the purpose and
242 limitations of each of these functions are described below.
245 - purpose: essential init to permit execution to reach board_init_f()
246 - no global_data or BSS
247 - there is no stack (ARMv7 may have one but it will soon be removed)
248 - must not set up SDRAM or use console
249 - must only do the bare minimum to allow execution to continue to
251 - this is almost never needed
252 - return normally from this function
255 - purpose: set up the machine ready for running board_init_r():
256 i.e. SDRAM and serial UART
257 - global_data is available
259 - BSS is not available, so you cannot use global/static variables,
260 only stack variables and global_data
262 Non-SPL-specific notes:
263 - dram_init() is called to set up DRAM. If already done in SPL this
267 - you can override the entire board_init_f() function with your own
269 - preloader_console_init() can be called here in extremis
270 - should set up SDRAM, and anything needed to make the UART work
271 - these is no need to clear BSS, it will be done by crt0.S
272 - must return normally from this function (don't call board_init_r()
275 Here the BSS is cleared. For SPL, if CONFIG_SPL_STACK_R is defined, then at
276 this point the stack and global_data are relocated to below
277 CONFIG_SPL_STACK_R_ADDR. For non-SPL, U-Boot is relocated to run at the top of
281 - purpose: main execution, common code
282 - global_data is available
284 - BSS is available, all static/global variables can be used
285 - execution eventually continues to main_loop()
287 Non-SPL-specific notes:
288 - U-Boot is relocated to the top of memory and is now running from
292 - stack is optionally in SDRAM, if CONFIG_SPL_STACK_R is defined and
293 CONFIG_SPL_STACK_R_ADDR points into SDRAM
294 - preloader_console_init() can be called here - typically this is
295 done by selecting CONFIG_SPL_BOARD_INIT and then supplying a
296 spl_board_init() function containing this call
297 - loads U-Boot or (in falcon mode) Linux
301 Configuration Options:
302 ----------------------
304 Configuration depends on the combination of board and CPU type; all
305 such information is kept in a configuration file
306 "include/configs/<board_name>.h".
308 Example: For a TQM823L module, all configuration settings are in
309 "include/configs/TQM823L.h".
312 Many of the options are named exactly as the corresponding Linux
313 kernel configuration options. The intention is to make it easier to
314 build a config tool - later.
317 The following options need to be configured:
319 - CPU Type: Define exactly one, e.g. CONFIG_MPC85XX.
321 - Board Type: Define exactly one, e.g. CONFIG_MPC8540ADS.
323 - CPU Daughterboard Type: (if CONFIG_ATSTK1000 is defined)
324 Define exactly one, e.g. CONFIG_ATSTK1002
326 - Marvell Family Member
327 CONFIG_SYS_MVFS - define it if you want to enable
328 multiple fs option at one time
329 for marvell soc family
331 - 8xx CPU Options: (if using an MPC8xx CPU)
332 CONFIG_8xx_GCLK_FREQ - deprecated: CPU clock if
333 get_gclk_freq() cannot work
334 e.g. if there is no 32KHz
335 reference PIT/RTC clock
336 CONFIG_8xx_OSCLK - PLL input clock (either EXTCLK
339 - 859/866/885 CPU options: (if using a MPC859 or MPC866 or MPC885 CPU):
340 CONFIG_SYS_8xx_CPUCLK_MIN
341 CONFIG_SYS_8xx_CPUCLK_MAX
342 CONFIG_8xx_CPUCLK_DEFAULT
343 See doc/README.MPC866
345 CONFIG_SYS_MEASURE_CPUCLK
347 Define this to measure the actual CPU clock instead
348 of relying on the correctness of the configured
349 values. Mostly useful for board bringup to make sure
350 the PLL is locked at the intended frequency. Note
351 that this requires a (stable) reference clock (32 kHz
352 RTC clock or CONFIG_SYS_8XX_XIN)
354 CONFIG_SYS_DELAYED_ICACHE
356 Define this option if you want to enable the
357 ICache only when Code runs from RAM.
362 Specifies that the core is a 64-bit PowerPC implementation (implements
363 the "64" category of the Power ISA). This is necessary for ePAPR
364 compliance, among other possible reasons.
366 CONFIG_SYS_FSL_TBCLK_DIV
368 Defines the core time base clock divider ratio compared to the
369 system clock. On most PQ3 devices this is 8, on newer QorIQ
370 devices it can be 16 or 32. The ratio varies from SoC to Soc.
372 CONFIG_SYS_FSL_PCIE_COMPAT
374 Defines the string to utilize when trying to match PCIe device
375 tree nodes for the given platform.
377 CONFIG_SYS_FSL_ERRATUM_A004510
379 Enables a workaround for erratum A004510. If set,
380 then CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV and
381 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY must be set.
383 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV
384 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV2 (optional)
386 Defines one or two SoC revisions (low 8 bits of SVR)
387 for which the A004510 workaround should be applied.
389 The rest of SVR is either not relevant to the decision
390 of whether the erratum is present (e.g. p2040 versus
391 p2041) or is implied by the build target, which controls
392 whether CONFIG_SYS_FSL_ERRATUM_A004510 is set.
394 See Freescale App Note 4493 for more information about
397 CONFIG_A003399_NOR_WORKAROUND
398 Enables a workaround for IFC erratum A003399. It is only
399 required during NOR boot.
401 CONFIG_A008044_WORKAROUND
402 Enables a workaround for T1040/T1042 erratum A008044. It is only
403 required during NAND boot and valid for Rev 1.0 SoC revision
405 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY
407 This is the value to write into CCSR offset 0x18600
408 according to the A004510 workaround.
410 CONFIG_SYS_FSL_DSP_DDR_ADDR
411 This value denotes start offset of DDR memory which is
412 connected exclusively to the DSP cores.
414 CONFIG_SYS_FSL_DSP_M2_RAM_ADDR
415 This value denotes start offset of M2 memory
416 which is directly connected to the DSP core.
418 CONFIG_SYS_FSL_DSP_M3_RAM_ADDR
419 This value denotes start offset of M3 memory which is directly
420 connected to the DSP core.
422 CONFIG_SYS_FSL_DSP_CCSRBAR_DEFAULT
423 This value denotes start offset of DSP CCSR space.
425 CONFIG_SYS_FSL_SINGLE_SOURCE_CLK
426 Single Source Clock is clocking mode present in some of FSL SoC's.
427 In this mode, a single differential clock is used to supply
428 clocks to the sysclock, ddrclock and usbclock.
430 CONFIG_SYS_CPC_REINIT_F
431 This CONFIG is defined when the CPC is configured as SRAM at the
432 time of U-Boot entry and is required to be re-initialized.
435 Indicates this SoC supports deep sleep feature. If deep sleep is
436 supported, core will start to execute uboot when wakes up.
438 - Generic CPU options:
439 CONFIG_SYS_GENERIC_GLOBAL_DATA
440 Defines global data is initialized in generic board board_init_f().
441 If this macro is defined, global data is created and cleared in
442 generic board board_init_f(). Without this macro, architecture/board
443 should initialize global data before calling board_init_f().
445 CONFIG_SYS_BIG_ENDIAN, CONFIG_SYS_LITTLE_ENDIAN
447 Defines the endianess of the CPU. Implementation of those
448 values is arch specific.
451 Freescale DDR driver in use. This type of DDR controller is
452 found in mpc83xx, mpc85xx, mpc86xx as well as some ARM core
455 CONFIG_SYS_FSL_DDR_ADDR
456 Freescale DDR memory-mapped register base.
458 CONFIG_SYS_FSL_DDR_EMU
459 Specify emulator support for DDR. Some DDR features such as
460 deskew training are not available.
462 CONFIG_SYS_FSL_DDRC_GEN1
463 Freescale DDR1 controller.
465 CONFIG_SYS_FSL_DDRC_GEN2
466 Freescale DDR2 controller.
468 CONFIG_SYS_FSL_DDRC_GEN3
469 Freescale DDR3 controller.
471 CONFIG_SYS_FSL_DDRC_GEN4
472 Freescale DDR4 controller.
474 CONFIG_SYS_FSL_DDRC_ARM_GEN3
475 Freescale DDR3 controller for ARM-based SoCs.
478 Board config to use DDR1. It can be enabled for SoCs with
479 Freescale DDR1 or DDR2 controllers, depending on the board
483 Board config to use DDR2. It can be enabled for SoCs with
484 Freescale DDR2 or DDR3 controllers, depending on the board
488 Board config to use DDR3. It can be enabled for SoCs with
489 Freescale DDR3 or DDR3L controllers.
492 Board config to use DDR3L. It can be enabled for SoCs with
496 Board config to use DDR4. It can be enabled for SoCs with
499 CONFIG_SYS_FSL_IFC_BE
500 Defines the IFC controller register space as Big Endian
502 CONFIG_SYS_FSL_IFC_LE
503 Defines the IFC controller register space as Little Endian
505 CONFIG_SYS_FSL_IFC_CLK_DIV
506 Defines divider of platform clock(clock input to IFC controller).
508 CONFIG_SYS_FSL_LBC_CLK_DIV
509 Defines divider of platform clock(clock input to eLBC controller).
511 CONFIG_SYS_FSL_PBL_PBI
512 It enables addition of RCW (Power on reset configuration) in built image.
513 Please refer doc/README.pblimage for more details
515 CONFIG_SYS_FSL_PBL_RCW
516 It adds PBI(pre-boot instructions) commands in u-boot build image.
517 PBI commands can be used to configure SoC before it starts the execution.
518 Please refer doc/README.pblimage for more details
521 It adds a target to create boot binary having SPL binary in PBI format
522 concatenated with u-boot binary.
524 CONFIG_SYS_FSL_DDR_BE
525 Defines the DDR controller register space as Big Endian
527 CONFIG_SYS_FSL_DDR_LE
528 Defines the DDR controller register space as Little Endian
530 CONFIG_SYS_FSL_DDR_SDRAM_BASE_PHY
531 Physical address from the view of DDR controllers. It is the
532 same as CONFIG_SYS_DDR_SDRAM_BASE for all Power SoCs. But
533 it could be different for ARM SoCs.
535 CONFIG_SYS_FSL_DDR_INTLV_256B
536 DDR controller interleaving on 256-byte. This is a special
537 interleaving mode, handled by Dickens for Freescale layerscape
540 CONFIG_SYS_FSL_DDR_MAIN_NUM_CTRLS
541 Number of controllers used as main memory.
543 CONFIG_SYS_FSL_OTHER_DDR_NUM_CTRLS
544 Number of controllers used for other than main memory.
546 CONFIG_SYS_FSL_HAS_DP_DDR
547 Defines the SoC has DP-DDR used for DPAA.
549 CONFIG_SYS_FSL_SEC_BE
550 Defines the SEC controller register space as Big Endian
552 CONFIG_SYS_FSL_SEC_LE
553 Defines the SEC controller register space as Little Endian
556 CONFIG_SYS_INIT_SP_OFFSET
558 Offset relative to CONFIG_SYS_SDRAM_BASE for initial stack
559 pointer. This is needed for the temporary stack before
562 CONFIG_SYS_MIPS_CACHE_MODE
564 Cache operation mode for the MIPS CPU.
565 See also arch/mips/include/asm/mipsregs.h.
567 CONF_CM_CACHABLE_NO_WA
570 CONF_CM_CACHABLE_NONCOHERENT
574 CONF_CM_CACHABLE_ACCELERATED
576 CONFIG_SYS_XWAY_EBU_BOOTCFG
578 Special option for Lantiq XWAY SoCs for booting from NOR flash.
579 See also arch/mips/cpu/mips32/start.S.
581 CONFIG_XWAY_SWAP_BYTES
583 Enable compilation of tools/xway-swap-bytes needed for Lantiq
584 XWAY SoCs for booting from NOR flash. The U-Boot image needs to
585 be swapped if a flash programmer is used.
588 CONFIG_SYS_EXCEPTION_VECTORS_HIGH
590 Select high exception vectors of the ARM core, e.g., do not
591 clear the V bit of the c1 register of CP15.
594 Generic timer clock source frequency.
596 COUNTER_FREQUENCY_REAL
597 Generic timer clock source frequency if the real clock is
598 different from COUNTER_FREQUENCY, and can only be determined
602 CONFIG_TEGRA_SUPPORT_NON_SECURE
604 Support executing U-Boot in non-secure (NS) mode. Certain
605 impossible actions will be skipped if the CPU is in NS mode,
606 such as ARM architectural timer initialization.
608 - Linux Kernel Interface:
611 U-Boot stores all clock information in Hz
612 internally. For binary compatibility with older Linux
613 kernels (which expect the clocks passed in the
614 bd_info data to be in MHz) the environment variable
615 "clocks_in_mhz" can be defined so that U-Boot
616 converts clock data to MHZ before passing it to the
618 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
619 "clocks_in_mhz=1" is automatically included in the
622 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
624 When transferring memsize parameter to Linux, some versions
625 expect it to be in bytes, others in MB.
626 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
630 New kernel versions are expecting firmware settings to be
631 passed using flattened device trees (based on open firmware
635 * New libfdt-based support
636 * Adds the "fdt" command
637 * The bootm command automatically updates the fdt
639 OF_CPU - The proper name of the cpus node (only required for
640 MPC512X and MPC5xxx based boards).
641 OF_SOC - The proper name of the soc node (only required for
642 MPC512X and MPC5xxx based boards).
643 OF_TBCLK - The timebase frequency.
644 OF_STDOUT_PATH - The path to the console device
646 boards with QUICC Engines require OF_QE to set UCC MAC
649 CONFIG_OF_BOARD_SETUP
651 Board code has addition modification that it wants to make
652 to the flat device tree before handing it off to the kernel
654 CONFIG_OF_SYSTEM_SETUP
656 Other code has addition modification that it wants to make
657 to the flat device tree before handing it off to the kernel.
658 This causes ft_system_setup() to be called before booting
663 U-Boot can detect if an IDE device is present or not.
664 If not, and this new config option is activated, U-Boot
665 removes the ATA node from the DTS before booting Linux,
666 so the Linux IDE driver does not probe the device and
667 crash. This is needed for buggy hardware (uc101) where
668 no pull down resistor is connected to the signal IDE5V_DD7.
670 CONFIG_MACH_TYPE [relevant for ARM only][mandatory]
672 This setting is mandatory for all boards that have only one
673 machine type and must be used to specify the machine type
674 number as it appears in the ARM machine registry
675 (see http://www.arm.linux.org.uk/developer/machines/).
676 Only boards that have multiple machine types supported
677 in a single configuration file and the machine type is
678 runtime discoverable, do not have to use this setting.
680 - vxWorks boot parameters:
682 bootvx constructs a valid bootline using the following
683 environments variables: bootdev, bootfile, ipaddr, netmask,
684 serverip, gatewayip, hostname, othbootargs.
685 It loads the vxWorks image pointed bootfile.
687 Note: If a "bootargs" environment is defined, it will overwride
688 the defaults discussed just above.
690 - Cache Configuration:
691 CONFIG_SYS_ICACHE_OFF - Do not enable instruction cache in U-Boot
692 CONFIG_SYS_DCACHE_OFF - Do not enable data cache in U-Boot
693 CONFIG_SYS_L2CACHE_OFF- Do not enable L2 cache in U-Boot
695 - Cache Configuration for ARM:
696 CONFIG_SYS_L2_PL310 - Enable support for ARM PL310 L2 cache
698 CONFIG_SYS_PL310_BASE - Physical base address of PL310
699 controller register space
704 Define this if you want support for Amba PrimeCell PL010 UARTs.
708 Define this if you want support for Amba PrimeCell PL011 UARTs.
712 If you have Amba PrimeCell PL011 UARTs, set this variable to
713 the clock speed of the UARTs.
717 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
718 define this to a list of base addresses for each (supported)
719 port. See e.g. include/configs/versatile.h
721 CONFIG_SERIAL_HW_FLOW_CONTROL
723 Define this variable to enable hw flow control in serial driver.
724 Current user of this option is drivers/serial/nsl16550.c driver
727 Depending on board, define exactly one serial port
728 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
729 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
730 console by defining CONFIG_8xx_CONS_NONE
732 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
733 port routines must be defined elsewhere
734 (i.e. serial_init(), serial_getc(), ...)
737 CONFIG_BAUDRATE - in bps
738 Select one of the baudrates listed in
739 CONFIG_SYS_BAUDRATE_TABLE, see below.
740 CONFIG_SYS_BRGCLK_PRESCALE, baudrate prescale
742 - Console Rx buffer length
743 With CONFIG_SYS_SMC_RXBUFLEN it is possible to define
744 the maximum receive buffer length for the SMC.
745 This option is actual only for 82xx and 8xx possible.
746 If using CONFIG_SYS_SMC_RXBUFLEN also CONFIG_SYS_MAXIDLE
747 must be defined, to setup the maximum idle timeout for
752 Only needed when CONFIG_BOOTDELAY is enabled;
753 define a command string that is automatically executed
754 when no character is read on the console interface
755 within "Boot Delay" after reset.
758 This can be used to pass arguments to the bootm
759 command. The value of CONFIG_BOOTARGS goes into the
760 environment value "bootargs".
762 CONFIG_RAMBOOT and CONFIG_NFSBOOT
763 The value of these goes into the environment as
764 "ramboot" and "nfsboot" respectively, and can be used
765 as a convenience, when switching between booting from
769 CONFIG_BOOTCOUNT_LIMIT
770 Implements a mechanism for detecting a repeating reboot
772 http://www.denx.de/wiki/view/DULG/UBootBootCountLimit
775 If no softreset save registers are found on the hardware
776 "bootcount" is stored in the environment. To prevent a
777 saveenv on all reboots, the environment variable
778 "upgrade_available" is used. If "upgrade_available" is
779 0, "bootcount" is always 0, if "upgrade_available" is
780 1 "bootcount" is incremented in the environment.
781 So the Userspace Applikation must set the "upgrade_available"
782 and "bootcount" variable to 0, if a boot was successfully.
787 When this option is #defined, the existence of the
788 environment variable "preboot" will be checked
789 immediately before starting the CONFIG_BOOTDELAY
790 countdown and/or running the auto-boot command resp.
791 entering interactive mode.
793 This feature is especially useful when "preboot" is
794 automatically generated or modified. For an example
795 see the LWMON board specific code: here "preboot" is
796 modified when the user holds down a certain
797 combination of keys on the (special) keyboard when
800 - Serial Download Echo Mode:
802 If defined to 1, all characters received during a
803 serial download (using the "loads" command) are
804 echoed back. This might be needed by some terminal
805 emulations (like "cu"), but may as well just take
806 time on others. This setting #define's the initial
807 value of the "loads_echo" environment variable.
809 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
811 Select one of the baudrates listed in
812 CONFIG_SYS_BAUDRATE_TABLE, see below.
815 Monitor commands can be included or excluded
816 from the build by using the #include files
817 <config_cmd_all.h> and #undef'ing unwanted
818 commands, or adding #define's for wanted commands.
820 The default command configuration includes all commands
821 except those marked below with a "*".
823 CONFIG_CMD_AES AES 128 CBC encrypt/decrypt
824 CONFIG_CMD_ASKENV * ask for env variable
825 CONFIG_CMD_BDI bdinfo
826 CONFIG_CMD_BOOTD bootd
827 CONFIG_CMD_BOOTI * ARM64 Linux kernel Image support
828 CONFIG_CMD_CACHE * icache, dcache
829 CONFIG_CMD_CONSOLE coninfo
830 CONFIG_CMD_CRC32 * crc32
831 CONFIG_CMD_DHCP * DHCP support
832 CONFIG_CMD_DIAG * Diagnostics
833 CONFIG_CMD_ECHO echo arguments
834 CONFIG_CMD_EDITENV edit env variable
835 CONFIG_CMD_ELF * bootelf, bootvx
836 CONFIG_CMD_ENV_EXISTS * check existence of env variable
837 CONFIG_CMD_EXPORTENV * export the environment
838 CONFIG_CMD_EXT2 * ext2 command support
839 CONFIG_CMD_EXT4 * ext4 command support
840 CONFIG_CMD_FS_GENERIC * filesystem commands (e.g. load, ls)
841 that work for multiple fs types
842 CONFIG_CMD_FS_UUID * Look up a filesystem UUID
843 CONFIG_CMD_SAVEENV saveenv
844 CONFIG_CMD_FAT * FAT command support
845 CONFIG_CMD_FLASH flinfo, erase, protect
846 CONFIG_CMD_FPGA FPGA device initialization support
847 CONFIG_CMD_GO * the 'go' command (exec code)
848 CONFIG_CMD_GREPENV * search environment
849 CONFIG_CMD_I2C * I2C serial bus support
850 CONFIG_CMD_IMI iminfo
851 CONFIG_CMD_IMLS List all images found in NOR flash
852 CONFIG_CMD_IMLS_NAND * List all images found in NAND flash
853 CONFIG_CMD_IMPORTENV * import an environment
854 CONFIG_CMD_INI * import data from an ini file into the env
855 CONFIG_CMD_ITEST Integer/string test of 2 values
856 CONFIG_CMD_LDRINFO * ldrinfo (display Blackfin loader)
857 CONFIG_CMD_LINK_LOCAL * link-local IP address auto-configuration
859 CONFIG_CMD_LOADB loadb
860 CONFIG_CMD_LOADS loads
861 CONFIG_CMD_MD5SUM * print md5 message digest
862 (requires CONFIG_CMD_MEMORY and CONFIG_MD5)
863 CONFIG_CMD_MEMINFO * Display detailed memory information
864 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
866 CONFIG_CMD_MEMTEST * mtest
867 CONFIG_CMD_MISC Misc functions like sleep etc
868 CONFIG_CMD_MMC * MMC memory mapped support
869 CONFIG_CMD_MII * MII utility commands
870 CONFIG_CMD_MTDPARTS * MTD partition support
871 CONFIG_CMD_NAND * NAND support
872 CONFIG_CMD_NET bootp, tftpboot, rarpboot
873 CONFIG_CMD_NFS NFS support
874 CONFIG_CMD_PCA953X * PCA953x I2C gpio commands
875 CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command
876 CONFIG_CMD_PCI * pciinfo
877 CONFIG_CMD_PCMCIA * PCMCIA support
878 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
880 CONFIG_CMD_PORTIO * Port I/O
881 CONFIG_CMD_READ * Read raw data from partition
882 CONFIG_CMD_REGINFO * Register dump
883 CONFIG_CMD_RUN run command in env variable
884 CONFIG_CMD_SANDBOX * sb command to access sandbox features
885 CONFIG_CMD_SAVES * save S record dump
886 CONFIG_SCSI * SCSI Support
887 CONFIG_CMD_SDRAM * print SDRAM configuration information
888 (requires CONFIG_CMD_I2C)
889 CONFIG_CMD_SETGETDCR Support for DCR Register access
891 CONFIG_CMD_SF * Read/write/erase SPI NOR flash
892 CONFIG_CMD_SHA1SUM * print sha1 memory digest
893 (requires CONFIG_CMD_MEMORY)
894 CONFIG_CMD_SOFTSWITCH * Soft switch setting command for BF60x
895 CONFIG_CMD_SOURCE "source" command Support
896 CONFIG_CMD_SPI * SPI serial bus support
897 CONFIG_CMD_TFTPSRV * TFTP transfer in server mode
898 CONFIG_CMD_TFTPPUT * TFTP put command (upload)
899 CONFIG_CMD_TIME * run command and report execution time (ARM specific)
900 CONFIG_CMD_TIMER * access to the system tick timer
901 CONFIG_CMD_USB * USB support
902 CONFIG_CMD_CDP * Cisco Discover Protocol support
903 CONFIG_CMD_MFSL * Microblaze FSL support
904 CONFIG_CMD_XIMG Load part of Multi Image
905 CONFIG_CMD_UUID * Generate random UUID or GUID string
907 EXAMPLE: If you want all functions except of network
908 support you can write:
910 #include "config_cmd_all.h"
911 #undef CONFIG_CMD_NET
914 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
916 Note: Don't enable the "icache" and "dcache" commands
917 (configuration option CONFIG_CMD_CACHE) unless you know
918 what you (and your U-Boot users) are doing. Data
919 cache cannot be enabled on systems like the 8xx or
920 8260 (where accesses to the IMMR region must be
921 uncached), and it cannot be disabled on all other
922 systems where we (mis-) use the data cache to hold an
923 initial stack and some data.
926 XXX - this list needs to get updated!
928 - Removal of commands
929 If no commands are needed to boot, you can disable
930 CONFIG_CMDLINE to remove them. In this case, the command line
931 will not be available, and when U-Boot wants to execute the
932 boot command (on start-up) it will call board_run_command()
933 instead. This can reduce image size significantly for very
934 simple boot procedures.
936 - Regular expression support:
938 If this variable is defined, U-Boot is linked against
939 the SLRE (Super Light Regular Expression) library,
940 which adds regex support to some commands, as for
941 example "env grep" and "setexpr".
945 If this variable is defined, U-Boot will use a device tree
946 to configure its devices, instead of relying on statically
947 compiled #defines in the board file. This option is
948 experimental and only available on a few boards. The device
949 tree is available in the global data as gd->fdt_blob.
951 U-Boot needs to get its device tree from somewhere. This can
952 be done using one of the three options below:
955 If this variable is defined, U-Boot will embed a device tree
956 binary in its image. This device tree file should be in the
957 board directory and called <soc>-<board>.dts. The binary file
958 is then picked up in board_init_f() and made available through
959 the global data structure as gd->blob.
962 If this variable is defined, U-Boot will build a device tree
963 binary. It will be called u-boot.dtb. Architecture-specific
964 code will locate it at run-time. Generally this works by:
966 cat u-boot.bin u-boot.dtb >image.bin
968 and in fact, U-Boot does this for you, creating a file called
969 u-boot-dtb.bin which is useful in the common case. You can
970 still use the individual files if you need something more
974 If this variable is defined, U-Boot will use the device tree
975 provided by the board at runtime instead of embedding one with
976 the image. Only boards defining board_fdt_blob_setup() support
977 this option (see include/fdtdec.h file).
981 If this variable is defined, it enables watchdog
982 support for the SoC. There must be support in the SoC
983 specific code for a watchdog. For the 8xx and 8260
984 CPUs, the SIU Watchdog feature is enabled in the SYPCR
985 register. When supported for a specific SoC is
986 available, then no further board specific code should
990 When using a watchdog circuitry external to the used
991 SoC, then define this variable and provide board
992 specific code for the "hw_watchdog_reset" function.
994 CONFIG_AT91_HW_WDT_TIMEOUT
995 specify the timeout in seconds. default 2 seconds.
998 CONFIG_VERSION_VARIABLE
999 If this variable is defined, an environment variable
1000 named "ver" is created by U-Boot showing the U-Boot
1001 version as printed by the "version" command.
1002 Any change to this variable will be reverted at the
1007 When CONFIG_CMD_DATE is selected, the type of the RTC
1008 has to be selected, too. Define exactly one of the
1011 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
1012 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
1013 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC
1014 CONFIG_RTC_MC146818 - use MC146818 RTC
1015 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
1016 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
1017 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
1018 CONFIG_RTC_DS1339 - use Maxim, Inc. DS1339 RTC
1019 CONFIG_RTC_DS164x - use Dallas DS164x RTC
1020 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
1021 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
1022 CONFIG_SYS_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
1023 CONFIG_SYS_RV3029_TCR - enable trickle charger on
1026 Note that if the RTC uses I2C, then the I2C interface
1027 must also be configured. See I2C Support, below.
1030 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
1032 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
1033 chip-ngpio pairs that tell the PCA953X driver the number of
1034 pins supported by a particular chip.
1036 Note that if the GPIO device uses I2C, then the I2C interface
1037 must also be configured. See I2C Support, below.
1040 When CONFIG_IO_TRACE is selected, U-Boot intercepts all I/O
1041 accesses and can checksum them or write a list of them out
1042 to memory. See the 'iotrace' command for details. This is
1043 useful for testing device drivers since it can confirm that
1044 the driver behaves the same way before and after a code
1045 change. Currently this is supported on sandbox and arm. To
1046 add support for your architecture, add '#include <iotrace.h>'
1047 to the bottom of arch/<arch>/include/asm/io.h and test.
1049 Example output from the 'iotrace stats' command is below.
1050 Note that if the trace buffer is exhausted, the checksum will
1051 still continue to operate.
1054 Start: 10000000 (buffer start address)
1055 Size: 00010000 (buffer size)
1056 Offset: 00000120 (current buffer offset)
1057 Output: 10000120 (start + offset)
1058 Count: 00000018 (number of trace records)
1059 CRC32: 9526fb66 (CRC32 of all trace records)
1061 - Timestamp Support:
1063 When CONFIG_TIMESTAMP is selected, the timestamp
1064 (date and time) of an image is printed by image
1065 commands like bootm or iminfo. This option is
1066 automatically enabled when you select CONFIG_CMD_DATE .
1068 - Partition Labels (disklabels) Supported:
1069 Zero or more of the following:
1070 CONFIG_MAC_PARTITION Apple's MacOS partition table.
1071 CONFIG_DOS_PARTITION MS Dos partition table, traditional on the
1072 Intel architecture, USB sticks, etc.
1073 CONFIG_ISO_PARTITION ISO partition table, used on CDROM etc.
1074 CONFIG_EFI_PARTITION GPT partition table, common when EFI is the
1075 bootloader. Note 2TB partition limit; see
1077 CONFIG_MTD_PARTITIONS Memory Technology Device partition table.
1079 If IDE or SCSI support is enabled (CONFIG_IDE or
1080 CONFIG_SCSI) you must configure support for at
1081 least one non-MTD partition type as well.
1084 CONFIG_IDE_RESET_ROUTINE - this is defined in several
1085 board configurations files but used nowhere!
1087 CONFIG_IDE_RESET - is this is defined, IDE Reset will
1088 be performed by calling the function
1089 ide_set_reset(int reset)
1090 which has to be defined in a board specific file
1095 Set this to enable ATAPI support.
1100 Set this to enable support for disks larger than 137GB
1101 Also look at CONFIG_SYS_64BIT_LBA.
1102 Whithout these , LBA48 support uses 32bit variables and will 'only'
1103 support disks up to 2.1TB.
1105 CONFIG_SYS_64BIT_LBA:
1106 When enabled, makes the IDE subsystem use 64bit sector addresses.
1110 At the moment only there is only support for the
1111 SYM53C8XX SCSI controller; define
1112 CONFIG_SCSI_SYM53C8XX to enable it.
1114 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
1115 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
1116 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
1117 maximum numbers of LUNs, SCSI ID's and target
1119 CONFIG_SYS_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
1121 The environment variable 'scsidevs' is set to the number of
1122 SCSI devices found during the last scan.
1124 - NETWORK Support (PCI):
1126 Support for Intel 8254x/8257x gigabit chips.
1129 Utility code for direct access to the SPI bus on Intel 8257x.
1130 This does not do anything useful unless you set at least one
1131 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
1133 CONFIG_E1000_SPI_GENERIC
1134 Allow generic access to the SPI bus on the Intel 8257x, for
1135 example with the "sspi" command.
1138 Management command for E1000 devices. When used on devices
1139 with SPI support you can reprogram the EEPROM from U-Boot.
1142 Support for Intel 82557/82559/82559ER chips.
1143 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
1144 write routine for first time initialisation.
1147 Support for Digital 2114x chips.
1148 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
1149 modem chip initialisation (KS8761/QS6611).
1152 Support for National dp83815 chips.
1155 Support for National dp8382[01] gigabit chips.
1157 - NETWORK Support (other):
1159 CONFIG_DRIVER_AT91EMAC
1160 Support for AT91RM9200 EMAC.
1163 Define this to use reduced MII inteface
1165 CONFIG_DRIVER_AT91EMAC_QUIET
1166 If this defined, the driver is quiet.
1167 The driver doen't show link status messages.
1169 CONFIG_CALXEDA_XGMAC
1170 Support for the Calxeda XGMAC device
1173 Support for SMSC's LAN91C96 chips.
1175 CONFIG_LAN91C96_USE_32_BIT
1176 Define this to enable 32 bit addressing
1179 Support for SMSC's LAN91C111 chip
1181 CONFIG_SMC91111_BASE
1182 Define this to hold the physical address
1183 of the device (I/O space)
1185 CONFIG_SMC_USE_32_BIT
1186 Define this if data bus is 32 bits
1188 CONFIG_SMC_USE_IOFUNCS
1189 Define this to use i/o functions instead of macros
1190 (some hardware wont work with macros)
1192 CONFIG_DRIVER_TI_EMAC
1193 Support for davinci emac
1195 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
1196 Define this if you have more then 3 PHYs.
1199 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
1201 CONFIG_FTGMAC100_EGIGA
1202 Define this to use GE link update with gigabit PHY.
1203 Define this if FTGMAC100 is connected to gigabit PHY.
1204 If your system has 10/100 PHY only, it might not occur
1205 wrong behavior. Because PHY usually return timeout or
1206 useless data when polling gigabit status and gigabit
1207 control registers. This behavior won't affect the
1208 correctnessof 10/100 link speed update.
1211 Support for SMSC's LAN911x and LAN921x chips
1214 Define this to hold the physical address
1215 of the device (I/O space)
1217 CONFIG_SMC911X_32_BIT
1218 Define this if data bus is 32 bits
1220 CONFIG_SMC911X_16_BIT
1221 Define this if data bus is 16 bits. If your processor
1222 automatically converts one 32 bit word to two 16 bit
1223 words you may also try CONFIG_SMC911X_32_BIT.
1226 Support for Renesas on-chip Ethernet controller
1228 CONFIG_SH_ETHER_USE_PORT
1229 Define the number of ports to be used
1231 CONFIG_SH_ETHER_PHY_ADDR
1232 Define the ETH PHY's address
1234 CONFIG_SH_ETHER_CACHE_WRITEBACK
1235 If this option is set, the driver enables cache flush.
1239 Support for PWM module on the imx6.
1243 Support TPM devices.
1245 CONFIG_TPM_TIS_INFINEON
1246 Support for Infineon i2c bus TPM devices. Only one device
1247 per system is supported at this time.
1249 CONFIG_TPM_TIS_I2C_BURST_LIMITATION
1250 Define the burst count bytes upper limit
1253 Support for STMicroelectronics TPM devices. Requires DM_TPM support.
1255 CONFIG_TPM_ST33ZP24_I2C
1256 Support for STMicroelectronics ST33ZP24 I2C devices.
1257 Requires TPM_ST33ZP24 and I2C.
1259 CONFIG_TPM_ST33ZP24_SPI
1260 Support for STMicroelectronics ST33ZP24 SPI devices.
1261 Requires TPM_ST33ZP24 and SPI.
1263 CONFIG_TPM_ATMEL_TWI
1264 Support for Atmel TWI TPM device. Requires I2C support.
1267 Support for generic parallel port TPM devices. Only one device
1268 per system is supported at this time.
1270 CONFIG_TPM_TIS_BASE_ADDRESS
1271 Base address where the generic TPM device is mapped
1272 to. Contemporary x86 systems usually map it at
1276 Add tpm monitor functions.
1277 Requires CONFIG_TPM. If CONFIG_TPM_AUTH_SESSIONS is set, also
1278 provides monitor access to authorized functions.
1281 Define this to enable the TPM support library which provides
1282 functional interfaces to some TPM commands.
1283 Requires support for a TPM device.
1285 CONFIG_TPM_AUTH_SESSIONS
1286 Define this to enable authorized functions in the TPM library.
1287 Requires CONFIG_TPM and CONFIG_SHA1.
1290 At the moment only the UHCI host controller is
1291 supported (PIP405, MIP405, MPC5200); define
1292 CONFIG_USB_UHCI to enable it.
1293 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
1294 and define CONFIG_USB_STORAGE to enable the USB
1297 Supported are USB Keyboards and USB Floppy drives
1299 MPC5200 USB requires additional defines:
1301 for 528 MHz Clock: 0x0001bbbb
1305 for differential drivers: 0x00001000
1306 for single ended drivers: 0x00005000
1307 for differential drivers on PSC3: 0x00000100
1308 for single ended drivers on PSC3: 0x00004100
1309 CONFIG_SYS_USB_EVENT_POLL
1310 May be defined to allow interrupt polling
1311 instead of using asynchronous interrupts
1313 CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
1314 txfilltuning field in the EHCI controller on reset.
1316 CONFIG_USB_DWC2_REG_ADDR the physical CPU address of the DWC2
1317 HW module registers.
1320 Define the below if you wish to use the USB console.
1321 Once firmware is rebuilt from a serial console issue the
1322 command "setenv stdin usbtty; setenv stdout usbtty" and
1323 attach your USB cable. The Unix command "dmesg" should print
1324 it has found a new device. The environment variable usbtty
1325 can be set to gserial or cdc_acm to enable your device to
1326 appear to a USB host as a Linux gserial device or a
1327 Common Device Class Abstract Control Model serial device.
1328 If you select usbtty = gserial you should be able to enumerate
1330 # modprobe usbserial vendor=0xVendorID product=0xProductID
1331 else if using cdc_acm, simply setting the environment
1332 variable usbtty to be cdc_acm should suffice. The following
1333 might be defined in YourBoardName.h
1336 Define this to build a UDC device
1339 Define this to have a tty type of device available to
1340 talk to the UDC device
1343 Define this to enable the high speed support for usb
1344 device and usbtty. If this feature is enabled, a routine
1345 int is_usbd_high_speed(void)
1346 also needs to be defined by the driver to dynamically poll
1347 whether the enumeration has succeded at high speed or full
1350 CONFIG_SYS_CONSOLE_IS_IN_ENV
1351 Define this if you want stdin, stdout &/or stderr to
1355 CONFIG_SYS_USB_EXTC_CLK 0xBLAH
1356 Derive USB clock from external clock "blah"
1357 - CONFIG_SYS_USB_EXTC_CLK 0x02
1359 If you have a USB-IF assigned VendorID then you may wish to
1360 define your own vendor specific values either in BoardName.h
1361 or directly in usbd_vendor_info.h. If you don't define
1362 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
1363 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
1364 should pretend to be a Linux device to it's target host.
1366 CONFIG_USBD_MANUFACTURER
1367 Define this string as the name of your company for
1368 - CONFIG_USBD_MANUFACTURER "my company"
1370 CONFIG_USBD_PRODUCT_NAME
1371 Define this string as the name of your product
1372 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
1374 CONFIG_USBD_VENDORID
1375 Define this as your assigned Vendor ID from the USB
1376 Implementors Forum. This *must* be a genuine Vendor ID
1377 to avoid polluting the USB namespace.
1378 - CONFIG_USBD_VENDORID 0xFFFF
1380 CONFIG_USBD_PRODUCTID
1381 Define this as the unique Product ID
1383 - CONFIG_USBD_PRODUCTID 0xFFFF
1385 - ULPI Layer Support:
1386 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
1387 the generic ULPI layer. The generic layer accesses the ULPI PHY
1388 via the platform viewport, so you need both the genric layer and
1389 the viewport enabled. Currently only Chipidea/ARC based
1390 viewport is supported.
1391 To enable the ULPI layer support, define CONFIG_USB_ULPI and
1392 CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
1393 If your ULPI phy needs a different reference clock than the
1394 standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to
1395 the appropriate value in Hz.
1398 The MMC controller on the Intel PXA is supported. To
1399 enable this define CONFIG_MMC. The MMC can be
1400 accessed from the boot prompt by mapping the device
1401 to physical memory similar to flash. Command line is
1402 enabled with CONFIG_CMD_MMC. The MMC driver also works with
1403 the FAT fs. This is enabled with CONFIG_CMD_FAT.
1406 Support for Renesas on-chip MMCIF controller
1408 CONFIG_SH_MMCIF_ADDR
1409 Define the base address of MMCIF registers
1412 Define the clock frequency for MMCIF
1414 CONFIG_SUPPORT_EMMC_BOOT
1415 Enable some additional features of the eMMC boot partitions.
1417 CONFIG_SUPPORT_EMMC_RPMB
1418 Enable the commands for reading, writing and programming the
1419 key for the Replay Protection Memory Block partition in eMMC.
1421 - USB Device Firmware Update (DFU) class support:
1422 CONFIG_USB_FUNCTION_DFU
1423 This enables the USB portion of the DFU USB class
1426 This enables the command "dfu" which is used to have
1427 U-Boot create a DFU class device via USB. This command
1428 requires that the "dfu_alt_info" environment variable be
1429 set and define the alt settings to expose to the host.
1432 This enables support for exposing (e)MMC devices via DFU.
1435 This enables support for exposing NAND devices via DFU.
1438 This enables support for exposing RAM via DFU.
1439 Note: DFU spec refer to non-volatile memory usage, but
1440 allow usages beyond the scope of spec - here RAM usage,
1441 one that would help mostly the developer.
1443 CONFIG_SYS_DFU_DATA_BUF_SIZE
1444 Dfu transfer uses a buffer before writing data to the
1445 raw storage device. Make the size (in bytes) of this buffer
1446 configurable. The size of this buffer is also configurable
1447 through the "dfu_bufsiz" environment variable.
1449 CONFIG_SYS_DFU_MAX_FILE_SIZE
1450 When updating files rather than the raw storage device,
1451 we use a static buffer to copy the file into and then write
1452 the buffer once we've been given the whole file. Define
1453 this to the maximum filesize (in bytes) for the buffer.
1454 Default is 4 MiB if undefined.
1456 DFU_DEFAULT_POLL_TIMEOUT
1457 Poll timeout [ms], is the timeout a device can send to the
1458 host. The host must wait for this timeout before sending
1459 a subsequent DFU_GET_STATUS request to the device.
1461 DFU_MANIFEST_POLL_TIMEOUT
1462 Poll timeout [ms], which the device sends to the host when
1463 entering dfuMANIFEST state. Host waits this timeout, before
1464 sending again an USB request to the device.
1466 - USB Device Android Fastboot support:
1467 CONFIG_USB_FUNCTION_FASTBOOT
1468 This enables the USB part of the fastboot gadget
1471 This enables the command "fastboot" which enables the Android
1472 fastboot mode for the platform's USB device. Fastboot is a USB
1473 protocol for downloading images, flashing and device control
1474 used on Android devices.
1475 See doc/README.android-fastboot for more information.
1477 CONFIG_ANDROID_BOOT_IMAGE
1478 This enables support for booting images which use the Android
1479 image format header.
1481 CONFIG_FASTBOOT_BUF_ADDR
1482 The fastboot protocol requires a large memory buffer for
1483 downloads. Define this to the starting RAM address to use for
1486 CONFIG_FASTBOOT_BUF_SIZE
1487 The fastboot protocol requires a large memory buffer for
1488 downloads. This buffer should be as large as possible for a
1489 platform. Define this to the size available RAM for fastboot.
1491 CONFIG_FASTBOOT_FLASH
1492 The fastboot protocol includes a "flash" command for writing
1493 the downloaded image to a non-volatile storage device. Define
1494 this to enable the "fastboot flash" command.
1496 CONFIG_FASTBOOT_FLASH_MMC_DEV
1497 The fastboot "flash" command requires additional information
1498 regarding the non-volatile storage device. Define this to
1499 the eMMC device that fastboot should use to store the image.
1501 CONFIG_FASTBOOT_GPT_NAME
1502 The fastboot "flash" command supports writing the downloaded
1503 image to the Protective MBR and the Primary GUID Partition
1504 Table. (Additionally, this downloaded image is post-processed
1505 to generate and write the Backup GUID Partition Table.)
1506 This occurs when the specified "partition name" on the
1507 "fastboot flash" command line matches this value.
1508 The default is "gpt" if undefined.
1510 CONFIG_FASTBOOT_MBR_NAME
1511 The fastboot "flash" command supports writing the downloaded
1513 This occurs when the "partition name" specified on the
1514 "fastboot flash" command line matches this value.
1515 If not defined the default value "mbr" is used.
1517 - Journaling Flash filesystem support:
1519 Define these for a default partition on a NAND device
1521 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1522 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1523 Define these for a default partition on a NOR device
1525 - FAT(File Allocation Table) filesystem write function support:
1528 Define this to enable support for saving memory data as a
1529 file in FAT formatted partition.
1531 This will also enable the command "fatwrite" enabling the
1532 user to write files to FAT.
1534 - FAT(File Allocation Table) filesystem cluster size:
1535 CONFIG_FS_FAT_MAX_CLUSTSIZE
1537 Define the max cluster size for fat operations else
1538 a default value of 65536 will be defined.
1541 See Kconfig help for available keyboard drivers.
1545 Define this to enable a custom keyboard support.
1546 This simply calls drv_keyboard_init() which must be
1547 defined in your board-specific files. This option is deprecated
1548 and is only used by novena. For new boards, use driver model
1553 Enable the Freescale DIU video driver. Reference boards for
1554 SOCs that have a DIU should define this macro to enable DIU
1555 support, and should also define these other macros:
1560 CONFIG_VIDEO_SW_CURSOR
1561 CONFIG_VGA_AS_SINGLE_DEVICE
1563 CONFIG_VIDEO_BMP_LOGO
1565 The DIU driver will look for the 'video-mode' environment
1566 variable, and if defined, enable the DIU as a console during
1567 boot. See the documentation file doc/README.video for a
1568 description of this variable.
1570 - LCD Support: CONFIG_LCD
1572 Define this to enable LCD support (for output to LCD
1573 display); also select one of the supported displays
1574 by defining one of these:
1578 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1580 CONFIG_NEC_NL6448AC33:
1582 NEC NL6448AC33-18. Active, color, single scan.
1584 CONFIG_NEC_NL6448BC20
1586 NEC NL6448BC20-08. 6.5", 640x480.
1587 Active, color, single scan.
1589 CONFIG_NEC_NL6448BC33_54
1591 NEC NL6448BC33-54. 10.4", 640x480.
1592 Active, color, single scan.
1596 Sharp 320x240. Active, color, single scan.
1597 It isn't 16x9, and I am not sure what it is.
1599 CONFIG_SHARP_LQ64D341
1601 Sharp LQ64D341 display, 640x480.
1602 Active, color, single scan.
1606 HLD1045 display, 640x480.
1607 Active, color, single scan.
1611 Optrex CBL50840-2 NF-FW 99 22 M5
1613 Hitachi LMG6912RPFC-00T
1617 320x240. Black & white.
1619 CONFIG_LCD_ALIGNMENT
1621 Normally the LCD is page-aligned (typically 4KB). If this is
1622 defined then the LCD will be aligned to this value instead.
1623 For ARM it is sometimes useful to use MMU_SECTION_SIZE
1624 here, since it is cheaper to change data cache settings on
1625 a per-section basis.
1630 Sometimes, for example if the display is mounted in portrait
1631 mode or even if it's mounted landscape but rotated by 180degree,
1632 we need to rotate our content of the display relative to the
1633 framebuffer, so that user can read the messages which are
1635 Once CONFIG_LCD_ROTATION is defined, the lcd_console will be
1636 initialized with a given rotation from "vl_rot" out of
1637 "vidinfo_t" which is provided by the board specific code.
1638 The value for vl_rot is coded as following (matching to
1639 fbcon=rotate:<n> linux-kernel commandline):
1640 0 = no rotation respectively 0 degree
1641 1 = 90 degree rotation
1642 2 = 180 degree rotation
1643 3 = 270 degree rotation
1645 If CONFIG_LCD_ROTATION is not defined, the console will be
1646 initialized with 0degree rotation.
1650 Support drawing of RLE8-compressed bitmaps on the LCD.
1654 Enables an 'i2c edid' command which can read EDID
1655 information over I2C from an attached LCD display.
1657 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1659 If this option is set, the environment is checked for
1660 a variable "splashimage". If found, the usual display
1661 of logo, copyright and system information on the LCD
1662 is suppressed and the BMP image at the address
1663 specified in "splashimage" is loaded instead. The
1664 console is redirected to the "nulldev", too. This
1665 allows for a "silent" boot where a splash screen is
1666 loaded very quickly after power-on.
1668 CONFIG_SPLASHIMAGE_GUARD
1670 If this option is set, then U-Boot will prevent the environment
1671 variable "splashimage" from being set to a problematic address
1672 (see doc/README.displaying-bmps).
1673 This option is useful for targets where, due to alignment
1674 restrictions, an improperly aligned BMP image will cause a data
1675 abort. If you think you will not have problems with unaligned
1676 accesses (for example because your toolchain prevents them)
1677 there is no need to set this option.
1679 CONFIG_SPLASH_SCREEN_ALIGN
1681 If this option is set the splash image can be freely positioned
1682 on the screen. Environment variable "splashpos" specifies the
1683 position as "x,y". If a positive number is given it is used as
1684 number of pixel from left/top. If a negative number is given it
1685 is used as number of pixel from right/bottom. You can also
1686 specify 'm' for centering the image.
1689 setenv splashpos m,m
1690 => image at center of screen
1692 setenv splashpos 30,20
1693 => image at x = 30 and y = 20
1695 setenv splashpos -10,m
1696 => vertically centered image
1697 at x = dspWidth - bmpWidth - 9
1699 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1701 If this option is set, additionally to standard BMP
1702 images, gzipped BMP images can be displayed via the
1703 splashscreen support or the bmp command.
1705 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1707 If this option is set, 8-bit RLE compressed BMP images
1708 can be displayed via the splashscreen support or the
1711 - Compression support:
1714 Enabled by default to support gzip compressed images.
1718 If this option is set, support for bzip2 compressed
1719 images is included. If not, only uncompressed and gzip
1720 compressed images are supported.
1722 NOTE: the bzip2 algorithm requires a lot of RAM, so
1723 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1728 If this option is set, support for lzma compressed
1731 Note: The LZMA algorithm adds between 2 and 4KB of code and it
1732 requires an amount of dynamic memory that is given by the
1735 (1846 + 768 << (lc + lp)) * sizeof(uint16)
1737 Where lc and lp stand for, respectively, Literal context bits
1738 and Literal pos bits.
1740 This value is upper-bounded by 14MB in the worst case. Anyway,
1741 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
1742 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
1743 a very small buffer.
1745 Use the lzmainfo tool to determinate the lc and lp values and
1746 then calculate the amount of needed dynamic memory (ensuring
1747 the appropriate CONFIG_SYS_MALLOC_LEN value).
1751 If this option is set, support for LZO compressed images
1757 The address of PHY on MII bus.
1759 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1761 The clock frequency of the MII bus
1765 If this option is set, support for speed/duplex
1766 detection of gigabit PHY is included.
1768 CONFIG_PHY_RESET_DELAY
1770 Some PHY like Intel LXT971A need extra delay after
1771 reset before any MII register access is possible.
1772 For such PHY, set this option to the usec delay
1773 required. (minimum 300usec for LXT971A)
1775 CONFIG_PHY_CMD_DELAY (ppc4xx)
1777 Some PHY like Intel LXT971A need extra delay after
1778 command issued before MII status register can be read
1783 Define a default value for the IP address to use for
1784 the default Ethernet interface, in case this is not
1785 determined through e.g. bootp.
1786 (Environment variable "ipaddr")
1788 - Server IP address:
1791 Defines a default value for the IP address of a TFTP
1792 server to contact when using the "tftboot" command.
1793 (Environment variable "serverip")
1795 CONFIG_KEEP_SERVERADDR
1797 Keeps the server's MAC address, in the env 'serveraddr'
1798 for passing to bootargs (like Linux's netconsole option)
1800 - Gateway IP address:
1803 Defines a default value for the IP address of the
1804 default router where packets to other networks are
1806 (Environment variable "gatewayip")
1811 Defines a default value for the subnet mask (or
1812 routing prefix) which is used to determine if an IP
1813 address belongs to the local subnet or needs to be
1814 forwarded through a router.
1815 (Environment variable "netmask")
1817 - Multicast TFTP Mode:
1820 Defines whether you want to support multicast TFTP as per
1821 rfc-2090; for example to work with atftp. Lets lots of targets
1822 tftp down the same boot image concurrently. Note: the Ethernet
1823 driver in use must provide a function: mcast() to join/leave a
1826 - BOOTP Recovery Mode:
1827 CONFIG_BOOTP_RANDOM_DELAY
1829 If you have many targets in a network that try to
1830 boot using BOOTP, you may want to avoid that all
1831 systems send out BOOTP requests at precisely the same
1832 moment (which would happen for instance at recovery
1833 from a power failure, when all systems will try to
1834 boot, thus flooding the BOOTP server. Defining
1835 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1836 inserted before sending out BOOTP requests. The
1837 following delays are inserted then:
1839 1st BOOTP request: delay 0 ... 1 sec
1840 2nd BOOTP request: delay 0 ... 2 sec
1841 3rd BOOTP request: delay 0 ... 4 sec
1843 BOOTP requests: delay 0 ... 8 sec
1845 CONFIG_BOOTP_ID_CACHE_SIZE
1847 BOOTP packets are uniquely identified using a 32-bit ID. The
1848 server will copy the ID from client requests to responses and
1849 U-Boot will use this to determine if it is the destination of
1850 an incoming response. Some servers will check that addresses
1851 aren't in use before handing them out (usually using an ARP
1852 ping) and therefore take up to a few hundred milliseconds to
1853 respond. Network congestion may also influence the time it
1854 takes for a response to make it back to the client. If that
1855 time is too long, U-Boot will retransmit requests. In order
1856 to allow earlier responses to still be accepted after these
1857 retransmissions, U-Boot's BOOTP client keeps a small cache of
1858 IDs. The CONFIG_BOOTP_ID_CACHE_SIZE controls the size of this
1859 cache. The default is to keep IDs for up to four outstanding
1860 requests. Increasing this will allow U-Boot to accept offers
1861 from a BOOTP client in networks with unusually high latency.
1863 - DHCP Advanced Options:
1864 You can fine tune the DHCP functionality by defining
1865 CONFIG_BOOTP_* symbols:
1867 CONFIG_BOOTP_SUBNETMASK
1868 CONFIG_BOOTP_GATEWAY
1869 CONFIG_BOOTP_HOSTNAME
1870 CONFIG_BOOTP_NISDOMAIN
1871 CONFIG_BOOTP_BOOTPATH
1872 CONFIG_BOOTP_BOOTFILESIZE
1875 CONFIG_BOOTP_SEND_HOSTNAME
1876 CONFIG_BOOTP_NTPSERVER
1877 CONFIG_BOOTP_TIMEOFFSET
1878 CONFIG_BOOTP_VENDOREX
1879 CONFIG_BOOTP_MAY_FAIL
1881 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1882 environment variable, not the BOOTP server.
1884 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
1885 after the configured retry count, the call will fail
1886 instead of starting over. This can be used to fail over
1887 to Link-local IP address configuration if the DHCP server
1890 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1891 serverip from a DHCP server, it is possible that more
1892 than one DNS serverip is offered to the client.
1893 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1894 serverip will be stored in the additional environment
1895 variable "dnsip2". The first DNS serverip is always
1896 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1899 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1900 to do a dynamic update of a DNS server. To do this, they
1901 need the hostname of the DHCP requester.
1902 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1903 of the "hostname" environment variable is passed as
1904 option 12 to the DHCP server.
1906 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1908 A 32bit value in microseconds for a delay between
1909 receiving a "DHCP Offer" and sending the "DHCP Request".
1910 This fixes a problem with certain DHCP servers that don't
1911 respond 100% of the time to a "DHCP request". E.g. On an
1912 AT91RM9200 processor running at 180MHz, this delay needed
1913 to be *at least* 15,000 usec before a Windows Server 2003
1914 DHCP server would reply 100% of the time. I recommend at
1915 least 50,000 usec to be safe. The alternative is to hope
1916 that one of the retries will be successful but note that
1917 the DHCP timeout and retry process takes a longer than
1920 - Link-local IP address negotiation:
1921 Negotiate with other link-local clients on the local network
1922 for an address that doesn't require explicit configuration.
1923 This is especially useful if a DHCP server cannot be guaranteed
1924 to exist in all environments that the device must operate.
1926 See doc/README.link-local for more information.
1929 CONFIG_CDP_DEVICE_ID
1931 The device id used in CDP trigger frames.
1933 CONFIG_CDP_DEVICE_ID_PREFIX
1935 A two character string which is prefixed to the MAC address
1940 A printf format string which contains the ascii name of
1941 the port. Normally is set to "eth%d" which sets
1942 eth0 for the first Ethernet, eth1 for the second etc.
1944 CONFIG_CDP_CAPABILITIES
1946 A 32bit integer which indicates the device capabilities;
1947 0x00000010 for a normal host which does not forwards.
1951 An ascii string containing the version of the software.
1955 An ascii string containing the name of the platform.
1959 A 32bit integer sent on the trigger.
1961 CONFIG_CDP_POWER_CONSUMPTION
1963 A 16bit integer containing the power consumption of the
1964 device in .1 of milliwatts.
1966 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1968 A byte containing the id of the VLAN.
1970 - Status LED: CONFIG_LED_STATUS
1972 Several configurations allow to display the current
1973 status using a LED. For instance, the LED will blink
1974 fast while running U-Boot code, stop blinking as
1975 soon as a reply to a BOOTP request was received, and
1976 start blinking slow once the Linux kernel is running
1977 (supported by a status LED driver in the Linux
1978 kernel). Defining CONFIG_LED_STATUS enables this
1983 CONFIG_LED_STATUS_GPIO
1984 The status LED can be connected to a GPIO pin.
1985 In such cases, the gpio_led driver can be used as a
1986 status LED backend implementation. Define CONFIG_LED_STATUS_GPIO
1987 to include the gpio_led driver in the U-Boot binary.
1989 CONFIG_GPIO_LED_INVERTED_TABLE
1990 Some GPIO connected LEDs may have inverted polarity in which
1991 case the GPIO high value corresponds to LED off state and
1992 GPIO low value corresponds to LED on state.
1993 In such cases CONFIG_GPIO_LED_INVERTED_TABLE may be defined
1994 with a list of GPIO LEDs that have inverted polarity.
1996 - CAN Support: CONFIG_CAN_DRIVER
1998 Defining CONFIG_CAN_DRIVER enables CAN driver support
1999 on those systems that support this (optional)
2000 feature, like the TQM8xxL modules.
2002 - I2C Support: CONFIG_SYS_I2C
2004 This enable the NEW i2c subsystem, and will allow you to use
2005 i2c commands at the u-boot command line (as long as you set
2006 CONFIG_CMD_I2C in CONFIG_COMMANDS) and communicate with i2c
2007 based realtime clock chips or other i2c devices. See
2008 common/cmd_i2c.c for a description of the command line
2011 ported i2c driver to the new framework:
2012 - drivers/i2c/soft_i2c.c:
2013 - activate first bus with CONFIG_SYS_I2C_SOFT define
2014 CONFIG_SYS_I2C_SOFT_SPEED and CONFIG_SYS_I2C_SOFT_SLAVE
2015 for defining speed and slave address
2016 - activate second bus with I2C_SOFT_DECLARATIONS2 define
2017 CONFIG_SYS_I2C_SOFT_SPEED_2 and CONFIG_SYS_I2C_SOFT_SLAVE_2
2018 for defining speed and slave address
2019 - activate third bus with I2C_SOFT_DECLARATIONS3 define
2020 CONFIG_SYS_I2C_SOFT_SPEED_3 and CONFIG_SYS_I2C_SOFT_SLAVE_3
2021 for defining speed and slave address
2022 - activate fourth bus with I2C_SOFT_DECLARATIONS4 define
2023 CONFIG_SYS_I2C_SOFT_SPEED_4 and CONFIG_SYS_I2C_SOFT_SLAVE_4
2024 for defining speed and slave address
2026 - drivers/i2c/fsl_i2c.c:
2027 - activate i2c driver with CONFIG_SYS_I2C_FSL
2028 define CONFIG_SYS_FSL_I2C_OFFSET for setting the register
2029 offset CONFIG_SYS_FSL_I2C_SPEED for the i2c speed and
2030 CONFIG_SYS_FSL_I2C_SLAVE for the slave addr of the first
2032 - If your board supports a second fsl i2c bus, define
2033 CONFIG_SYS_FSL_I2C2_OFFSET for the register offset
2034 CONFIG_SYS_FSL_I2C2_SPEED for the speed and
2035 CONFIG_SYS_FSL_I2C2_SLAVE for the slave address of the
2038 - drivers/i2c/tegra_i2c.c:
2039 - activate this driver with CONFIG_SYS_I2C_TEGRA
2040 - This driver adds 4 i2c buses with a fix speed from
2041 100000 and the slave addr 0!
2043 - drivers/i2c/ppc4xx_i2c.c
2044 - activate this driver with CONFIG_SYS_I2C_PPC4XX
2045 - CONFIG_SYS_I2C_PPC4XX_CH0 activate hardware channel 0
2046 - CONFIG_SYS_I2C_PPC4XX_CH1 activate hardware channel 1
2048 - drivers/i2c/i2c_mxc.c
2049 - activate this driver with CONFIG_SYS_I2C_MXC
2050 - enable bus 1 with CONFIG_SYS_I2C_MXC_I2C1
2051 - enable bus 2 with CONFIG_SYS_I2C_MXC_I2C2
2052 - enable bus 3 with CONFIG_SYS_I2C_MXC_I2C3
2053 - enable bus 4 with CONFIG_SYS_I2C_MXC_I2C4
2054 - define speed for bus 1 with CONFIG_SYS_MXC_I2C1_SPEED
2055 - define slave for bus 1 with CONFIG_SYS_MXC_I2C1_SLAVE
2056 - define speed for bus 2 with CONFIG_SYS_MXC_I2C2_SPEED
2057 - define slave for bus 2 with CONFIG_SYS_MXC_I2C2_SLAVE
2058 - define speed for bus 3 with CONFIG_SYS_MXC_I2C3_SPEED
2059 - define slave for bus 3 with CONFIG_SYS_MXC_I2C3_SLAVE
2060 - define speed for bus 4 with CONFIG_SYS_MXC_I2C4_SPEED
2061 - define slave for bus 4 with CONFIG_SYS_MXC_I2C4_SLAVE
2062 If those defines are not set, default value is 100000
2063 for speed, and 0 for slave.
2065 - drivers/i2c/rcar_i2c.c:
2066 - activate this driver with CONFIG_SYS_I2C_RCAR
2067 - This driver adds 4 i2c buses
2069 - CONFIG_SYS_RCAR_I2C0_BASE for setting the register channel 0
2070 - CONFIG_SYS_RCAR_I2C0_SPEED for for the speed channel 0
2071 - CONFIG_SYS_RCAR_I2C1_BASE for setting the register channel 1
2072 - CONFIG_SYS_RCAR_I2C1_SPEED for for the speed channel 1
2073 - CONFIG_SYS_RCAR_I2C2_BASE for setting the register channel 2
2074 - CONFIG_SYS_RCAR_I2C2_SPEED for for the speed channel 2
2075 - CONFIG_SYS_RCAR_I2C3_BASE for setting the register channel 3
2076 - CONFIG_SYS_RCAR_I2C3_SPEED for for the speed channel 3
2077 - CONFIF_SYS_RCAR_I2C_NUM_CONTROLLERS for number of i2c buses
2079 - drivers/i2c/sh_i2c.c:
2080 - activate this driver with CONFIG_SYS_I2C_SH
2081 - This driver adds from 2 to 5 i2c buses
2083 - CONFIG_SYS_I2C_SH_BASE0 for setting the register channel 0
2084 - CONFIG_SYS_I2C_SH_SPEED0 for for the speed channel 0
2085 - CONFIG_SYS_I2C_SH_BASE1 for setting the register channel 1
2086 - CONFIG_SYS_I2C_SH_SPEED1 for for the speed channel 1
2087 - CONFIG_SYS_I2C_SH_BASE2 for setting the register channel 2
2088 - CONFIG_SYS_I2C_SH_SPEED2 for for the speed channel 2
2089 - CONFIG_SYS_I2C_SH_BASE3 for setting the register channel 3
2090 - CONFIG_SYS_I2C_SH_SPEED3 for for the speed channel 3
2091 - CONFIG_SYS_I2C_SH_BASE4 for setting the register channel 4
2092 - CONFIG_SYS_I2C_SH_SPEED4 for for the speed channel 4
2093 - CONFIG_SYS_I2C_SH_NUM_CONTROLLERS for number of i2c buses
2095 - drivers/i2c/omap24xx_i2c.c
2096 - activate this driver with CONFIG_SYS_I2C_OMAP24XX
2097 - CONFIG_SYS_OMAP24_I2C_SPEED speed channel 0
2098 - CONFIG_SYS_OMAP24_I2C_SLAVE slave addr channel 0
2099 - CONFIG_SYS_OMAP24_I2C_SPEED1 speed channel 1
2100 - CONFIG_SYS_OMAP24_I2C_SLAVE1 slave addr channel 1
2101 - CONFIG_SYS_OMAP24_I2C_SPEED2 speed channel 2
2102 - CONFIG_SYS_OMAP24_I2C_SLAVE2 slave addr channel 2
2103 - CONFIG_SYS_OMAP24_I2C_SPEED3 speed channel 3
2104 - CONFIG_SYS_OMAP24_I2C_SLAVE3 slave addr channel 3
2105 - CONFIG_SYS_OMAP24_I2C_SPEED4 speed channel 4
2106 - CONFIG_SYS_OMAP24_I2C_SLAVE4 slave addr channel 4
2108 - drivers/i2c/zynq_i2c.c
2109 - activate this driver with CONFIG_SYS_I2C_ZYNQ
2110 - set CONFIG_SYS_I2C_ZYNQ_SPEED for speed setting
2111 - set CONFIG_SYS_I2C_ZYNQ_SLAVE for slave addr
2113 - drivers/i2c/s3c24x0_i2c.c:
2114 - activate this driver with CONFIG_SYS_I2C_S3C24X0
2115 - This driver adds i2c buses (11 for Exynos5250, Exynos5420
2116 9 i2c buses for Exynos4 and 1 for S3C24X0 SoCs from Samsung)
2117 with a fix speed from 100000 and the slave addr 0!
2119 - drivers/i2c/ihs_i2c.c
2120 - activate this driver with CONFIG_SYS_I2C_IHS
2121 - CONFIG_SYS_I2C_IHS_CH0 activate hardware channel 0
2122 - CONFIG_SYS_I2C_IHS_SPEED_0 speed channel 0
2123 - CONFIG_SYS_I2C_IHS_SLAVE_0 slave addr channel 0
2124 - CONFIG_SYS_I2C_IHS_CH1 activate hardware channel 1
2125 - CONFIG_SYS_I2C_IHS_SPEED_1 speed channel 1
2126 - CONFIG_SYS_I2C_IHS_SLAVE_1 slave addr channel 1
2127 - CONFIG_SYS_I2C_IHS_CH2 activate hardware channel 2
2128 - CONFIG_SYS_I2C_IHS_SPEED_2 speed channel 2
2129 - CONFIG_SYS_I2C_IHS_SLAVE_2 slave addr channel 2
2130 - CONFIG_SYS_I2C_IHS_CH3 activate hardware channel 3
2131 - CONFIG_SYS_I2C_IHS_SPEED_3 speed channel 3
2132 - CONFIG_SYS_I2C_IHS_SLAVE_3 slave addr channel 3
2133 - activate dual channel with CONFIG_SYS_I2C_IHS_DUAL
2134 - CONFIG_SYS_I2C_IHS_SPEED_0_1 speed channel 0_1
2135 - CONFIG_SYS_I2C_IHS_SLAVE_0_1 slave addr channel 0_1
2136 - CONFIG_SYS_I2C_IHS_SPEED_1_1 speed channel 1_1
2137 - CONFIG_SYS_I2C_IHS_SLAVE_1_1 slave addr channel 1_1
2138 - CONFIG_SYS_I2C_IHS_SPEED_2_1 speed channel 2_1
2139 - CONFIG_SYS_I2C_IHS_SLAVE_2_1 slave addr channel 2_1
2140 - CONFIG_SYS_I2C_IHS_SPEED_3_1 speed channel 3_1
2141 - CONFIG_SYS_I2C_IHS_SLAVE_3_1 slave addr channel 3_1
2145 CONFIG_SYS_NUM_I2C_BUSES
2146 Hold the number of i2c buses you want to use.
2148 CONFIG_SYS_I2C_DIRECT_BUS
2149 define this, if you don't use i2c muxes on your hardware.
2150 if CONFIG_SYS_I2C_MAX_HOPS is not defined or == 0 you can
2153 CONFIG_SYS_I2C_MAX_HOPS
2154 define how many muxes are maximal consecutively connected
2155 on one i2c bus. If you not use i2c muxes, omit this
2158 CONFIG_SYS_I2C_BUSES
2159 hold a list of buses you want to use, only used if
2160 CONFIG_SYS_I2C_DIRECT_BUS is not defined, for example
2161 a board with CONFIG_SYS_I2C_MAX_HOPS = 1 and
2162 CONFIG_SYS_NUM_I2C_BUSES = 9:
2164 CONFIG_SYS_I2C_BUSES {{0, {I2C_NULL_HOP}}, \
2165 {0, {{I2C_MUX_PCA9547, 0x70, 1}}}, \
2166 {0, {{I2C_MUX_PCA9547, 0x70, 2}}}, \
2167 {0, {{I2C_MUX_PCA9547, 0x70, 3}}}, \
2168 {0, {{I2C_MUX_PCA9547, 0x70, 4}}}, \
2169 {0, {{I2C_MUX_PCA9547, 0x70, 5}}}, \
2170 {1, {I2C_NULL_HOP}}, \
2171 {1, {{I2C_MUX_PCA9544, 0x72, 1}}}, \
2172 {1, {{I2C_MUX_PCA9544, 0x72, 2}}}, \
2176 bus 0 on adapter 0 without a mux
2177 bus 1 on adapter 0 with a PCA9547 on address 0x70 port 1
2178 bus 2 on adapter 0 with a PCA9547 on address 0x70 port 2
2179 bus 3 on adapter 0 with a PCA9547 on address 0x70 port 3
2180 bus 4 on adapter 0 with a PCA9547 on address 0x70 port 4
2181 bus 5 on adapter 0 with a PCA9547 on address 0x70 port 5
2182 bus 6 on adapter 1 without a mux
2183 bus 7 on adapter 1 with a PCA9544 on address 0x72 port 1
2184 bus 8 on adapter 1 with a PCA9544 on address 0x72 port 2
2186 If you do not have i2c muxes on your board, omit this define.
2188 - Legacy I2C Support:
2189 If you use the software i2c interface (CONFIG_SYS_I2C_SOFT)
2190 then the following macros need to be defined (examples are
2191 from include/configs/lwmon.h):
2195 (Optional). Any commands necessary to enable the I2C
2196 controller or configure ports.
2198 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
2202 (Only for MPC8260 CPU). The I/O port to use (the code
2203 assumes both bits are on the same port). Valid values
2204 are 0..3 for ports A..D.
2208 The code necessary to make the I2C data line active
2209 (driven). If the data line is open collector, this
2212 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
2216 The code necessary to make the I2C data line tri-stated
2217 (inactive). If the data line is open collector, this
2220 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
2224 Code that returns true if the I2C data line is high,
2227 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
2231 If <bit> is true, sets the I2C data line high. If it
2232 is false, it clears it (low).
2234 eg: #define I2C_SDA(bit) \
2235 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
2236 else immr->im_cpm.cp_pbdat &= ~PB_SDA
2240 If <bit> is true, sets the I2C clock line high. If it
2241 is false, it clears it (low).
2243 eg: #define I2C_SCL(bit) \
2244 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
2245 else immr->im_cpm.cp_pbdat &= ~PB_SCL
2249 This delay is invoked four times per clock cycle so this
2250 controls the rate of data transfer. The data rate thus
2251 is 1 / (I2C_DELAY * 4). Often defined to be something
2254 #define I2C_DELAY udelay(2)
2256 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
2258 If your arch supports the generic GPIO framework (asm/gpio.h),
2259 then you may alternatively define the two GPIOs that are to be
2260 used as SCL / SDA. Any of the previous I2C_xxx macros will
2261 have GPIO-based defaults assigned to them as appropriate.
2263 You should define these to the GPIO value as given directly to
2264 the generic GPIO functions.
2266 CONFIG_SYS_I2C_INIT_BOARD
2268 When a board is reset during an i2c bus transfer
2269 chips might think that the current transfer is still
2270 in progress. On some boards it is possible to access
2271 the i2c SCLK line directly, either by using the
2272 processor pin as a GPIO or by having a second pin
2273 connected to the bus. If this option is defined a
2274 custom i2c_init_board() routine in boards/xxx/board.c
2275 is run early in the boot sequence.
2277 CONFIG_I2C_MULTI_BUS
2279 This option allows the use of multiple I2C buses, each of which
2280 must have a controller. At any point in time, only one bus is
2281 active. To switch to a different bus, use the 'i2c dev' command.
2282 Note that bus numbering is zero-based.
2284 CONFIG_SYS_I2C_NOPROBES
2286 This option specifies a list of I2C devices that will be skipped
2287 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
2288 is set, specify a list of bus-device pairs. Otherwise, specify
2289 a 1D array of device addresses
2292 #undef CONFIG_I2C_MULTI_BUS
2293 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
2295 will skip addresses 0x50 and 0x68 on a board with one I2C bus
2297 #define CONFIG_I2C_MULTI_BUS
2298 #define CONFIG_SYS_I2C_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
2300 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
2302 CONFIG_SYS_SPD_BUS_NUM
2304 If defined, then this indicates the I2C bus number for DDR SPD.
2305 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
2307 CONFIG_SYS_RTC_BUS_NUM
2309 If defined, then this indicates the I2C bus number for the RTC.
2310 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
2312 CONFIG_SOFT_I2C_READ_REPEATED_START
2314 defining this will force the i2c_read() function in
2315 the soft_i2c driver to perform an I2C repeated start
2316 between writing the address pointer and reading the
2317 data. If this define is omitted the default behaviour
2318 of doing a stop-start sequence will be used. Most I2C
2319 devices can use either method, but some require one or
2322 - SPI Support: CONFIG_SPI
2324 Enables SPI driver (so far only tested with
2325 SPI EEPROM, also an instance works with Crystal A/D and
2326 D/As on the SACSng board)
2330 Enables the driver for SPI controller on SuperH. Currently
2331 only SH7757 is supported.
2335 Enables a software (bit-bang) SPI driver rather than
2336 using hardware support. This is a general purpose
2337 driver that only requires three general I/O port pins
2338 (two outputs, one input) to function. If this is
2339 defined, the board configuration must define several
2340 SPI configuration items (port pins to use, etc). For
2341 an example, see include/configs/sacsng.h.
2345 Enables a hardware SPI driver for general-purpose reads
2346 and writes. As with CONFIG_SOFT_SPI, the board configuration
2347 must define a list of chip-select function pointers.
2348 Currently supported on some MPC8xxx processors. For an
2349 example, see include/configs/mpc8349emds.h.
2353 Enables the driver for the SPI controllers on i.MX and MXC
2354 SoCs. Currently i.MX31/35/51 are supported.
2356 CONFIG_SYS_SPI_MXC_WAIT
2357 Timeout for waiting until spi transfer completed.
2358 default: (CONFIG_SYS_HZ/100) /* 10 ms */
2360 - FPGA Support: CONFIG_FPGA
2362 Enables FPGA subsystem.
2364 CONFIG_FPGA_<vendor>
2366 Enables support for specific chip vendors.
2369 CONFIG_FPGA_<family>
2371 Enables support for FPGA family.
2372 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
2376 Specify the number of FPGA devices to support.
2378 CONFIG_SYS_FPGA_PROG_FEEDBACK
2380 Enable printing of hash marks during FPGA configuration.
2382 CONFIG_SYS_FPGA_CHECK_BUSY
2384 Enable checks on FPGA configuration interface busy
2385 status by the configuration function. This option
2386 will require a board or device specific function to
2391 If defined, a function that provides delays in the FPGA
2392 configuration driver.
2394 CONFIG_SYS_FPGA_CHECK_CTRLC
2395 Allow Control-C to interrupt FPGA configuration
2397 CONFIG_SYS_FPGA_CHECK_ERROR
2399 Check for configuration errors during FPGA bitfile
2400 loading. For example, abort during Virtex II
2401 configuration if the INIT_B line goes low (which
2402 indicated a CRC error).
2404 CONFIG_SYS_FPGA_WAIT_INIT
2406 Maximum time to wait for the INIT_B line to de-assert
2407 after PROB_B has been de-asserted during a Virtex II
2408 FPGA configuration sequence. The default time is 500
2411 CONFIG_SYS_FPGA_WAIT_BUSY
2413 Maximum time to wait for BUSY to de-assert during
2414 Virtex II FPGA configuration. The default is 5 ms.
2416 CONFIG_SYS_FPGA_WAIT_CONFIG
2418 Time to wait after FPGA configuration. The default is
2421 - Configuration Management:
2424 Some SoCs need special image types (e.g. U-Boot binary
2425 with a special header) as build targets. By defining
2426 CONFIG_BUILD_TARGET in the SoC / board header, this
2427 special image will be automatically built upon calling
2432 If defined, this string will be added to the U-Boot
2433 version information (U_BOOT_VERSION)
2435 - Vendor Parameter Protection:
2437 U-Boot considers the values of the environment
2438 variables "serial#" (Board Serial Number) and
2439 "ethaddr" (Ethernet Address) to be parameters that
2440 are set once by the board vendor / manufacturer, and
2441 protects these variables from casual modification by
2442 the user. Once set, these variables are read-only,
2443 and write or delete attempts are rejected. You can
2444 change this behaviour:
2446 If CONFIG_ENV_OVERWRITE is #defined in your config
2447 file, the write protection for vendor parameters is
2448 completely disabled. Anybody can change or delete
2451 Alternatively, if you define _both_ an ethaddr in the
2452 default env _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2453 Ethernet address is installed in the environment,
2454 which can be changed exactly ONCE by the user. [The
2455 serial# is unaffected by this, i. e. it remains
2458 The same can be accomplished in a more flexible way
2459 for any variable by configuring the type of access
2460 to allow for those variables in the ".flags" variable
2461 or define CONFIG_ENV_FLAGS_LIST_STATIC.
2466 Define this variable to enable the reservation of
2467 "protected RAM", i. e. RAM which is not overwritten
2468 by U-Boot. Define CONFIG_PRAM to hold the number of
2469 kB you want to reserve for pRAM. You can overwrite
2470 this default value by defining an environment
2471 variable "pram" to the number of kB you want to
2472 reserve. Note that the board info structure will
2473 still show the full amount of RAM. If pRAM is
2474 reserved, a new environment variable "mem" will
2475 automatically be defined to hold the amount of
2476 remaining RAM in a form that can be passed as boot
2477 argument to Linux, for instance like that:
2479 setenv bootargs ... mem=\${mem}
2482 This way you can tell Linux not to use this memory,
2483 either, which results in a memory region that will
2484 not be affected by reboots.
2486 *WARNING* If your board configuration uses automatic
2487 detection of the RAM size, you must make sure that
2488 this memory test is non-destructive. So far, the
2489 following board configurations are known to be
2492 IVMS8, IVML24, SPD8xx, TQM8xxL,
2493 HERMES, IP860, RPXlite, LWMON,
2496 - Access to physical memory region (> 4GB)
2497 Some basic support is provided for operations on memory not
2498 normally accessible to U-Boot - e.g. some architectures
2499 support access to more than 4GB of memory on 32-bit
2500 machines using physical address extension or similar.
2501 Define CONFIG_PHYSMEM to access this basic support, which
2502 currently only supports clearing the memory.
2507 Define this variable to stop the system in case of a
2508 fatal error, so that you have to reset it manually.
2509 This is probably NOT a good idea for an embedded
2510 system where you want the system to reboot
2511 automatically as fast as possible, but it may be
2512 useful during development since you can try to debug
2513 the conditions that lead to the situation.
2515 CONFIG_NET_RETRY_COUNT
2517 This variable defines the number of retries for
2518 network operations like ARP, RARP, TFTP, or BOOTP
2519 before giving up the operation. If not defined, a
2520 default value of 5 is used.
2524 Timeout waiting for an ARP reply in milliseconds.
2528 Timeout in milliseconds used in NFS protocol.
2529 If you encounter "ERROR: Cannot umount" in nfs command,
2530 try longer timeout such as
2531 #define CONFIG_NFS_TIMEOUT 10000UL
2533 - Command Interpreter:
2534 CONFIG_AUTO_COMPLETE
2536 Enable auto completion of commands using TAB.
2538 CONFIG_SYS_PROMPT_HUSH_PS2
2540 This defines the secondary prompt string, which is
2541 printed when the command interpreter needs more input
2542 to complete a command. Usually "> ".
2546 In the current implementation, the local variables
2547 space and global environment variables space are
2548 separated. Local variables are those you define by
2549 simply typing `name=value'. To access a local
2550 variable later on, you have write `$name' or
2551 `${name}'; to execute the contents of a variable
2552 directly type `$name' at the command prompt.
2554 Global environment variables are those you use
2555 setenv/printenv to work with. To run a command stored
2556 in such a variable, you need to use the run command,
2557 and you must not use the '$' sign to access them.
2559 To store commands and special characters in a
2560 variable, please use double quotation marks
2561 surrounding the whole text of the variable, instead
2562 of the backslashes before semicolons and special
2565 - Command Line Editing and History:
2566 CONFIG_CMDLINE_EDITING
2568 Enable editing and History functions for interactive
2569 command line input operations
2571 - Command Line PS1/PS2 support:
2572 CONFIG_CMDLINE_PS_SUPPORT
2574 Enable support for changing the command prompt string
2575 at run-time. Only static string is supported so far.
2576 The string is obtained from environment variables PS1
2579 - Default Environment:
2580 CONFIG_EXTRA_ENV_SETTINGS
2582 Define this to contain any number of null terminated
2583 strings (variable = value pairs) that will be part of
2584 the default environment compiled into the boot image.
2586 For example, place something like this in your
2587 board's config file:
2589 #define CONFIG_EXTRA_ENV_SETTINGS \
2593 Warning: This method is based on knowledge about the
2594 internal format how the environment is stored by the
2595 U-Boot code. This is NOT an official, exported
2596 interface! Although it is unlikely that this format
2597 will change soon, there is no guarantee either.
2598 You better know what you are doing here.
2600 Note: overly (ab)use of the default environment is
2601 discouraged. Make sure to check other ways to preset
2602 the environment like the "source" command or the
2605 CONFIG_ENV_VARS_UBOOT_CONFIG
2607 Define this in order to add variables describing the
2608 U-Boot build configuration to the default environment.
2609 These will be named arch, cpu, board, vendor, and soc.
2611 Enabling this option will cause the following to be defined:
2619 CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG
2621 Define this in order to add variables describing certain
2622 run-time determined information about the hardware to the
2623 environment. These will be named board_name, board_rev.
2625 CONFIG_DELAY_ENVIRONMENT
2627 Normally the environment is loaded when the board is
2628 initialised so that it is available to U-Boot. This inhibits
2629 that so that the environment is not available until
2630 explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL
2631 this is instead controlled by the value of
2632 /config/load-environment.
2634 - DataFlash Support:
2635 CONFIG_HAS_DATAFLASH
2637 Defining this option enables DataFlash features and
2638 allows to read/write in Dataflash via the standard
2641 - Serial Flash support
2644 Defining this option enables SPI flash commands
2645 'sf probe/read/write/erase/update'.
2647 Usage requires an initial 'probe' to define the serial
2648 flash parameters, followed by read/write/erase/update
2651 The following defaults may be provided by the platform
2652 to handle the common case when only a single serial
2653 flash is present on the system.
2655 CONFIG_SF_DEFAULT_BUS Bus identifier
2656 CONFIG_SF_DEFAULT_CS Chip-select
2657 CONFIG_SF_DEFAULT_MODE (see include/spi.h)
2658 CONFIG_SF_DEFAULT_SPEED in Hz
2662 Define this option to include a destructive SPI flash
2665 CONFIG_SF_DUAL_FLASH Dual flash memories
2667 Define this option to use dual flash support where two flash
2668 memories can be connected with a given cs line.
2669 Currently Xilinx Zynq qspi supports these type of connections.
2671 - SystemACE Support:
2674 Adding this option adds support for Xilinx SystemACE
2675 chips attached via some sort of local bus. The address
2676 of the chip must also be defined in the
2677 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
2679 #define CONFIG_SYSTEMACE
2680 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
2682 When SystemACE support is added, the "ace" device type
2683 becomes available to the fat commands, i.e. fatls.
2685 - TFTP Fixed UDP Port:
2688 If this is defined, the environment variable tftpsrcp
2689 is used to supply the TFTP UDP source port value.
2690 If tftpsrcp isn't defined, the normal pseudo-random port
2691 number generator is used.
2693 Also, the environment variable tftpdstp is used to supply
2694 the TFTP UDP destination port value. If tftpdstp isn't
2695 defined, the normal port 69 is used.
2697 The purpose for tftpsrcp is to allow a TFTP server to
2698 blindly start the TFTP transfer using the pre-configured
2699 target IP address and UDP port. This has the effect of
2700 "punching through" the (Windows XP) firewall, allowing
2701 the remainder of the TFTP transfer to proceed normally.
2702 A better solution is to properly configure the firewall,
2703 but sometimes that is not allowed.
2708 Enable the hash verify command (hash -v). This adds to code
2711 Note: There is also a sha1sum command, which should perhaps
2712 be deprecated in favour of 'hash sha1'.
2714 - bootcount support:
2715 CONFIG_BOOTCOUNT_LIMIT
2717 This enables the bootcounter support, see:
2718 http://www.denx.de/wiki/DULG/UBootBootCountLimit
2721 enable special bootcounter support on at91sam9xe based boards.
2723 enable special bootcounter support on da850 based boards.
2724 CONFIG_BOOTCOUNT_RAM
2725 enable support for the bootcounter in RAM
2726 CONFIG_BOOTCOUNT_I2C
2727 enable support for the bootcounter on an i2c (like RTC) device.
2728 CONFIG_SYS_I2C_RTC_ADDR = i2c chip address
2729 CONFIG_SYS_BOOTCOUNT_ADDR = i2c addr which is used for
2731 CONFIG_BOOTCOUNT_ALEN = address len
2733 - Show boot progress:
2734 CONFIG_SHOW_BOOT_PROGRESS
2736 Defining this option allows to add some board-
2737 specific code (calling a user-provided function
2738 "show_boot_progress(int)") that enables you to show
2739 the system's boot progress on some display (for
2740 example, some LED's) on your board. At the moment,
2741 the following checkpoints are implemented:
2744 Legacy uImage format:
2747 1 common/cmd_bootm.c before attempting to boot an image
2748 -1 common/cmd_bootm.c Image header has bad magic number
2749 2 common/cmd_bootm.c Image header has correct magic number
2750 -2 common/cmd_bootm.c Image header has bad checksum
2751 3 common/cmd_bootm.c Image header has correct checksum
2752 -3 common/cmd_bootm.c Image data has bad checksum
2753 4 common/cmd_bootm.c Image data has correct checksum
2754 -4 common/cmd_bootm.c Image is for unsupported architecture
2755 5 common/cmd_bootm.c Architecture check OK
2756 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
2757 6 common/cmd_bootm.c Image Type check OK
2758 -6 common/cmd_bootm.c gunzip uncompression error
2759 -7 common/cmd_bootm.c Unimplemented compression type
2760 7 common/cmd_bootm.c Uncompression OK
2761 8 common/cmd_bootm.c No uncompress/copy overwrite error
2762 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
2764 9 common/image.c Start initial ramdisk verification
2765 -10 common/image.c Ramdisk header has bad magic number
2766 -11 common/image.c Ramdisk header has bad checksum
2767 10 common/image.c Ramdisk header is OK
2768 -12 common/image.c Ramdisk data has bad checksum
2769 11 common/image.c Ramdisk data has correct checksum
2770 12 common/image.c Ramdisk verification complete, start loading
2771 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
2772 13 common/image.c Start multifile image verification
2773 14 common/image.c No initial ramdisk, no multifile, continue.
2775 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
2777 -30 arch/powerpc/lib/board.c Fatal error, hang the system
2778 -31 post/post.c POST test failed, detected by post_output_backlog()
2779 -32 post/post.c POST test failed, detected by post_run_single()
2781 34 common/cmd_doc.c before loading a Image from a DOC device
2782 -35 common/cmd_doc.c Bad usage of "doc" command
2783 35 common/cmd_doc.c correct usage of "doc" command
2784 -36 common/cmd_doc.c No boot device
2785 36 common/cmd_doc.c correct boot device
2786 -37 common/cmd_doc.c Unknown Chip ID on boot device
2787 37 common/cmd_doc.c correct chip ID found, device available
2788 -38 common/cmd_doc.c Read Error on boot device
2789 38 common/cmd_doc.c reading Image header from DOC device OK
2790 -39 common/cmd_doc.c Image header has bad magic number
2791 39 common/cmd_doc.c Image header has correct magic number
2792 -40 common/cmd_doc.c Error reading Image from DOC device
2793 40 common/cmd_doc.c Image header has correct magic number
2794 41 common/cmd_ide.c before loading a Image from a IDE device
2795 -42 common/cmd_ide.c Bad usage of "ide" command
2796 42 common/cmd_ide.c correct usage of "ide" command
2797 -43 common/cmd_ide.c No boot device
2798 43 common/cmd_ide.c boot device found
2799 -44 common/cmd_ide.c Device not available
2800 44 common/cmd_ide.c Device available
2801 -45 common/cmd_ide.c wrong partition selected
2802 45 common/cmd_ide.c partition selected
2803 -46 common/cmd_ide.c Unknown partition table
2804 46 common/cmd_ide.c valid partition table found
2805 -47 common/cmd_ide.c Invalid partition type
2806 47 common/cmd_ide.c correct partition type
2807 -48 common/cmd_ide.c Error reading Image Header on boot device
2808 48 common/cmd_ide.c reading Image Header from IDE device OK
2809 -49 common/cmd_ide.c Image header has bad magic number
2810 49 common/cmd_ide.c Image header has correct magic number
2811 -50 common/cmd_ide.c Image header has bad checksum
2812 50 common/cmd_ide.c Image header has correct checksum
2813 -51 common/cmd_ide.c Error reading Image from IDE device
2814 51 common/cmd_ide.c reading Image from IDE device OK
2815 52 common/cmd_nand.c before loading a Image from a NAND device
2816 -53 common/cmd_nand.c Bad usage of "nand" command
2817 53 common/cmd_nand.c correct usage of "nand" command
2818 -54 common/cmd_nand.c No boot device
2819 54 common/cmd_nand.c boot device found
2820 -55 common/cmd_nand.c Unknown Chip ID on boot device
2821 55 common/cmd_nand.c correct chip ID found, device available
2822 -56 common/cmd_nand.c Error reading Image Header on boot device
2823 56 common/cmd_nand.c reading Image Header from NAND device OK
2824 -57 common/cmd_nand.c Image header has bad magic number
2825 57 common/cmd_nand.c Image header has correct magic number
2826 -58 common/cmd_nand.c Error reading Image from NAND device
2827 58 common/cmd_nand.c reading Image from NAND device OK
2829 -60 common/env_common.c Environment has a bad CRC, using default
2831 64 net/eth.c starting with Ethernet configuration.
2832 -64 net/eth.c no Ethernet found.
2833 65 net/eth.c Ethernet found.
2835 -80 common/cmd_net.c usage wrong
2836 80 common/cmd_net.c before calling net_loop()
2837 -81 common/cmd_net.c some error in net_loop() occurred
2838 81 common/cmd_net.c net_loop() back without error
2839 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
2840 82 common/cmd_net.c trying automatic boot
2841 83 common/cmd_net.c running "source" command
2842 -83 common/cmd_net.c some error in automatic boot or "source" command
2843 84 common/cmd_net.c end without errors
2848 100 common/cmd_bootm.c Kernel FIT Image has correct format
2849 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
2850 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
2851 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
2852 102 common/cmd_bootm.c Kernel unit name specified
2853 -103 common/cmd_bootm.c Can't get kernel subimage node offset
2854 103 common/cmd_bootm.c Found configuration node
2855 104 common/cmd_bootm.c Got kernel subimage node offset
2856 -104 common/cmd_bootm.c Kernel subimage hash verification failed
2857 105 common/cmd_bootm.c Kernel subimage hash verification OK
2858 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
2859 106 common/cmd_bootm.c Architecture check OK
2860 -106 common/cmd_bootm.c Kernel subimage has wrong type
2861 107 common/cmd_bootm.c Kernel subimage type OK
2862 -107 common/cmd_bootm.c Can't get kernel subimage data/size
2863 108 common/cmd_bootm.c Got kernel subimage data/size
2864 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
2865 -109 common/cmd_bootm.c Can't get kernel subimage type
2866 -110 common/cmd_bootm.c Can't get kernel subimage comp
2867 -111 common/cmd_bootm.c Can't get kernel subimage os
2868 -112 common/cmd_bootm.c Can't get kernel subimage load address
2869 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
2871 120 common/image.c Start initial ramdisk verification
2872 -120 common/image.c Ramdisk FIT image has incorrect format
2873 121 common/image.c Ramdisk FIT image has correct format
2874 122 common/image.c No ramdisk subimage unit name, using configuration
2875 -122 common/image.c Can't get configuration for ramdisk subimage
2876 123 common/image.c Ramdisk unit name specified
2877 -124 common/image.c Can't get ramdisk subimage node offset
2878 125 common/image.c Got ramdisk subimage node offset
2879 -125 common/image.c Ramdisk subimage hash verification failed
2880 126 common/image.c Ramdisk subimage hash verification OK
2881 -126 common/image.c Ramdisk subimage for unsupported architecture
2882 127 common/image.c Architecture check OK
2883 -127 common/image.c Can't get ramdisk subimage data/size
2884 128 common/image.c Got ramdisk subimage data/size
2885 129 common/image.c Can't get ramdisk load address
2886 -129 common/image.c Got ramdisk load address
2888 -130 common/cmd_doc.c Incorrect FIT image format
2889 131 common/cmd_doc.c FIT image format OK
2891 -140 common/cmd_ide.c Incorrect FIT image format
2892 141 common/cmd_ide.c FIT image format OK
2894 -150 common/cmd_nand.c Incorrect FIT image format
2895 151 common/cmd_nand.c FIT image format OK
2897 - legacy image format:
2898 CONFIG_IMAGE_FORMAT_LEGACY
2899 enables the legacy image format support in U-Boot.
2902 enabled if CONFIG_FIT_SIGNATURE is not defined.
2904 CONFIG_DISABLE_IMAGE_LEGACY
2905 disable the legacy image format
2907 This define is introduced, as the legacy image format is
2908 enabled per default for backward compatibility.
2910 - Standalone program support:
2911 CONFIG_STANDALONE_LOAD_ADDR
2913 This option defines a board specific value for the
2914 address where standalone program gets loaded, thus
2915 overwriting the architecture dependent default
2918 - Frame Buffer Address:
2921 Define CONFIG_FB_ADDR if you want to use specific
2922 address for frame buffer. This is typically the case
2923 when using a graphics controller has separate video
2924 memory. U-Boot will then place the frame buffer at
2925 the given address instead of dynamically reserving it
2926 in system RAM by calling lcd_setmem(), which grabs
2927 the memory for the frame buffer depending on the
2928 configured panel size.
2930 Please see board_init_f function.
2932 - Automatic software updates via TFTP server
2934 CONFIG_UPDATE_TFTP_CNT_MAX
2935 CONFIG_UPDATE_TFTP_MSEC_MAX
2937 These options enable and control the auto-update feature;
2938 for a more detailed description refer to doc/README.update.
2940 - MTD Support (mtdparts command, UBI support)
2943 Adds the MTD device infrastructure from the Linux kernel.
2944 Needed for mtdparts command support.
2946 CONFIG_MTD_PARTITIONS
2948 Adds the MTD partitioning infrastructure from the Linux
2949 kernel. Needed for UBI support.
2954 Adds commands for interacting with MTD partitions formatted
2955 with the UBI flash translation layer
2957 Requires also defining CONFIG_RBTREE
2959 CONFIG_UBI_SILENCE_MSG
2961 Make the verbose messages from UBI stop printing. This leaves
2962 warnings and errors enabled.
2965 CONFIG_MTD_UBI_WL_THRESHOLD
2966 This parameter defines the maximum difference between the highest
2967 erase counter value and the lowest erase counter value of eraseblocks
2968 of UBI devices. When this threshold is exceeded, UBI starts performing
2969 wear leveling by means of moving data from eraseblock with low erase
2970 counter to eraseblocks with high erase counter.
2972 The default value should be OK for SLC NAND flashes, NOR flashes and
2973 other flashes which have eraseblock life-cycle 100000 or more.
2974 However, in case of MLC NAND flashes which typically have eraseblock
2975 life-cycle less than 10000, the threshold should be lessened (e.g.,
2976 to 128 or 256, although it does not have to be power of 2).
2980 CONFIG_MTD_UBI_BEB_LIMIT
2981 This option specifies the maximum bad physical eraseblocks UBI
2982 expects on the MTD device (per 1024 eraseblocks). If the
2983 underlying flash does not admit of bad eraseblocks (e.g. NOR
2984 flash), this value is ignored.
2986 NAND datasheets often specify the minimum and maximum NVM
2987 (Number of Valid Blocks) for the flashes' endurance lifetime.
2988 The maximum expected bad eraseblocks per 1024 eraseblocks
2989 then can be calculated as "1024 * (1 - MinNVB / MaxNVB)",
2990 which gives 20 for most NANDs (MaxNVB is basically the total
2991 count of eraseblocks on the chip).
2993 To put it differently, if this value is 20, UBI will try to
2994 reserve about 1.9% of physical eraseblocks for bad blocks
2995 handling. And that will be 1.9% of eraseblocks on the entire
2996 NAND chip, not just the MTD partition UBI attaches. This means
2997 that if you have, say, a NAND flash chip admits maximum 40 bad
2998 eraseblocks, and it is split on two MTD partitions of the same
2999 size, UBI will reserve 40 eraseblocks when attaching a
3004 CONFIG_MTD_UBI_FASTMAP
3005 Fastmap is a mechanism which allows attaching an UBI device
3006 in nearly constant time. Instead of scanning the whole MTD device it
3007 only has to locate a checkpoint (called fastmap) on the device.
3008 The on-flash fastmap contains all information needed to attach
3009 the device. Using fastmap makes only sense on large devices where
3010 attaching by scanning takes long. UBI will not automatically install
3011 a fastmap on old images, but you can set the UBI parameter
3012 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT to 1 if you want so. Please note
3013 that fastmap-enabled images are still usable with UBI implementations
3014 without fastmap support. On typical flash devices the whole fastmap
3015 fits into one PEB. UBI will reserve PEBs to hold two fastmaps.
3017 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT
3018 Set this parameter to enable fastmap automatically on images
3022 CONFIG_MTD_UBI_FM_DEBUG
3023 Enable UBI fastmap debug
3029 Adds commands for interacting with UBI volumes formatted as
3030 UBIFS. UBIFS is read-only in u-boot.
3032 Requires UBI support as well as CONFIG_LZO
3034 CONFIG_UBIFS_SILENCE_MSG
3036 Make the verbose messages from UBIFS stop printing. This leaves
3037 warnings and errors enabled.
3041 Enable building of SPL globally.
3044 LDSCRIPT for linking the SPL binary.
3046 CONFIG_SPL_MAX_FOOTPRINT
3047 Maximum size in memory allocated to the SPL, BSS included.
3048 When defined, the linker checks that the actual memory
3049 used by SPL from _start to __bss_end does not exceed it.
3050 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3051 must not be both defined at the same time.
3054 Maximum size of the SPL image (text, data, rodata, and
3055 linker lists sections), BSS excluded.
3056 When defined, the linker checks that the actual size does
3059 CONFIG_SPL_TEXT_BASE
3060 TEXT_BASE for linking the SPL binary.
3062 CONFIG_SPL_RELOC_TEXT_BASE
3063 Address to relocate to. If unspecified, this is equal to
3064 CONFIG_SPL_TEXT_BASE (i.e. no relocation is done).
3066 CONFIG_SPL_BSS_START_ADDR
3067 Link address for the BSS within the SPL binary.
3069 CONFIG_SPL_BSS_MAX_SIZE
3070 Maximum size in memory allocated to the SPL BSS.
3071 When defined, the linker checks that the actual memory used
3072 by SPL from __bss_start to __bss_end does not exceed it.
3073 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3074 must not be both defined at the same time.
3077 Adress of the start of the stack SPL will use
3079 CONFIG_SPL_PANIC_ON_RAW_IMAGE
3080 When defined, SPL will panic() if the image it has
3081 loaded does not have a signature.
3082 Defining this is useful when code which loads images
3083 in SPL cannot guarantee that absolutely all read errors
3085 An example is the LPC32XX MLC NAND driver, which will
3086 consider that a completely unreadable NAND block is bad,
3087 and thus should be skipped silently.
3089 CONFIG_SPL_RELOC_STACK
3090 Adress of the start of the stack SPL will use after
3091 relocation. If unspecified, this is equal to
3094 CONFIG_SYS_SPL_MALLOC_START
3095 Starting address of the malloc pool used in SPL.
3096 When this option is set the full malloc is used in SPL and
3097 it is set up by spl_init() and before that, the simple malloc()
3098 can be used if CONFIG_SYS_MALLOC_F is defined.
3100 CONFIG_SYS_SPL_MALLOC_SIZE
3101 The size of the malloc pool used in SPL.
3103 CONFIG_SPL_FRAMEWORK
3104 Enable the SPL framework under common/. This framework
3105 supports MMC, NAND and YMODEM loading of U-Boot and NAND
3106 NAND loading of the Linux Kernel.
3109 Enable booting directly to an OS from SPL.
3110 See also: doc/README.falcon
3112 CONFIG_SPL_DISPLAY_PRINT
3113 For ARM, enable an optional function to print more information
3114 about the running system.
3116 CONFIG_SPL_INIT_MINIMAL
3117 Arch init code should be built for a very small image
3119 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_PARTITION
3120 Partition on the MMC to load U-Boot from when the MMC is being
3123 CONFIG_SYS_MMCSD_RAW_MODE_KERNEL_SECTOR
3124 Sector to load kernel uImage from when MMC is being
3125 used in raw mode (for Falcon mode)
3127 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTOR,
3128 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTORS
3129 Sector and number of sectors to load kernel argument
3130 parameters from when MMC is being used in raw mode
3133 CONFIG_SYS_MMCSD_FS_BOOT_PARTITION
3134 Partition on the MMC to load U-Boot from when the MMC is being
3137 CONFIG_SPL_FS_LOAD_PAYLOAD_NAME
3138 Filename to read to load U-Boot when reading from filesystem
3140 CONFIG_SPL_FS_LOAD_KERNEL_NAME
3141 Filename to read to load kernel uImage when reading
3142 from filesystem (for Falcon mode)
3144 CONFIG_SPL_FS_LOAD_ARGS_NAME
3145 Filename to read to load kernel argument parameters
3146 when reading from filesystem (for Falcon mode)
3148 CONFIG_SPL_MPC83XX_WAIT_FOR_NAND
3149 Set this for NAND SPL on PPC mpc83xx targets, so that
3150 start.S waits for the rest of the SPL to load before
3151 continuing (the hardware starts execution after just
3152 loading the first page rather than the full 4K).
3154 CONFIG_SPL_SKIP_RELOCATE
3155 Avoid SPL relocation
3157 CONFIG_SPL_NAND_BASE
3158 Include nand_base.c in the SPL. Requires
3159 CONFIG_SPL_NAND_DRIVERS.
3161 CONFIG_SPL_NAND_DRIVERS
3162 SPL uses normal NAND drivers, not minimal drivers.
3165 Include standard software ECC in the SPL
3167 CONFIG_SPL_NAND_SIMPLE
3168 Support for NAND boot using simple NAND drivers that
3169 expose the cmd_ctrl() interface.
3172 Support for a lightweight UBI (fastmap) scanner and
3175 CONFIG_SPL_NAND_RAW_ONLY
3176 Support to boot only raw u-boot.bin images. Use this only
3177 if you need to save space.
3179 CONFIG_SPL_COMMON_INIT_DDR
3180 Set for common ddr init with serial presence detect in
3183 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
3184 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
3185 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
3186 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
3187 CONFIG_SYS_NAND_ECCBYTES
3188 Defines the size and behavior of the NAND that SPL uses
3191 CONFIG_SPL_NAND_BOOT
3192 Add support NAND boot
3194 CONFIG_SYS_NAND_U_BOOT_OFFS
3195 Location in NAND to read U-Boot from
3197 CONFIG_SYS_NAND_U_BOOT_DST
3198 Location in memory to load U-Boot to
3200 CONFIG_SYS_NAND_U_BOOT_SIZE
3201 Size of image to load
3203 CONFIG_SYS_NAND_U_BOOT_START
3204 Entry point in loaded image to jump to
3206 CONFIG_SYS_NAND_HW_ECC_OOBFIRST
3207 Define this if you need to first read the OOB and then the
3208 data. This is used, for example, on davinci platforms.
3210 CONFIG_SPL_OMAP3_ID_NAND
3211 Support for an OMAP3-specific set of functions to return the
3212 ID and MFR of the first attached NAND chip, if present.
3214 CONFIG_SPL_RAM_DEVICE
3215 Support for running image already present in ram, in SPL binary
3218 Image offset to which the SPL should be padded before appending
3219 the SPL payload. By default, this is defined as
3220 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3221 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3222 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3225 Final target image containing SPL and payload. Some SPLs
3226 use an arch-specific makefile fragment instead, for
3227 example if more than one image needs to be produced.
3229 CONFIG_FIT_SPL_PRINT
3230 Printing information about a FIT image adds quite a bit of
3231 code to SPL. So this is normally disabled in SPL. Use this
3232 option to re-enable it. This will affect the output of the
3233 bootm command when booting a FIT image.
3237 Enable building of TPL globally.
3240 Image offset to which the TPL should be padded before appending
3241 the TPL payload. By default, this is defined as
3242 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3243 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3244 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3246 - Interrupt support (PPC):
3248 There are common interrupt_init() and timer_interrupt()
3249 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
3250 for CPU specific initialization. interrupt_init_cpu()
3251 should set decrementer_count to appropriate value. If
3252 CPU resets decrementer automatically after interrupt
3253 (ppc4xx) it should set decrementer_count to zero.
3254 timer_interrupt() calls timer_interrupt_cpu() for CPU
3255 specific handling. If board has watchdog / status_led
3256 / other_activity_monitor it works automatically from
3257 general timer_interrupt().
3260 Board initialization settings:
3261 ------------------------------
3263 During Initialization u-boot calls a number of board specific functions
3264 to allow the preparation of board specific prerequisites, e.g. pin setup
3265 before drivers are initialized. To enable these callbacks the
3266 following configuration macros have to be defined. Currently this is
3267 architecture specific, so please check arch/your_architecture/lib/board.c
3268 typically in board_init_f() and board_init_r().
3270 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
3271 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
3272 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
3273 - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
3275 Configuration Settings:
3276 -----------------------
3278 - CONFIG_SYS_SUPPORT_64BIT_DATA: Defined automatically if compiled as 64-bit.
3279 Optionally it can be defined to support 64-bit memory commands.
3281 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
3282 undefine this when you're short of memory.
3284 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
3285 width of the commands listed in the 'help' command output.
3287 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
3288 prompt for user input.
3290 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
3292 - CONFIG_SYS_PBSIZE: Buffer size for Console output
3294 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
3296 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
3297 the application (usually a Linux kernel) when it is
3300 - CONFIG_SYS_BAUDRATE_TABLE:
3301 List of legal baudrate settings for this board.
3303 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
3304 Begin and End addresses of the area used by the
3307 - CONFIG_SYS_ALT_MEMTEST:
3308 Enable an alternate, more extensive memory test.
3310 - CONFIG_SYS_MEMTEST_SCRATCH:
3311 Scratch address used by the alternate memory test
3312 You only need to set this if address zero isn't writeable
3314 - CONFIG_SYS_MEM_RESERVE_SECURE
3315 Only implemented for ARMv8 for now.
3316 If defined, the size of CONFIG_SYS_MEM_RESERVE_SECURE memory
3317 is substracted from total RAM and won't be reported to OS.
3318 This memory can be used as secure memory. A variable
3319 gd->arch.secure_ram is used to track the location. In systems
3320 the RAM base is not zero, or RAM is divided into banks,
3321 this variable needs to be recalcuated to get the address.
3323 - CONFIG_SYS_MEM_TOP_HIDE:
3324 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
3325 this specified memory area will get subtracted from the top
3326 (end) of RAM and won't get "touched" at all by U-Boot. By
3327 fixing up gd->ram_size the Linux kernel should gets passed
3328 the now "corrected" memory size and won't touch it either.
3329 This should work for arch/ppc and arch/powerpc. Only Linux
3330 board ports in arch/powerpc with bootwrapper support that
3331 recalculate the memory size from the SDRAM controller setup
3332 will have to get fixed in Linux additionally.
3334 This option can be used as a workaround for the 440EPx/GRx
3335 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
3338 WARNING: Please make sure that this value is a multiple of
3339 the Linux page size (normally 4k). If this is not the case,
3340 then the end address of the Linux memory will be located at a
3341 non page size aligned address and this could cause major
3344 - CONFIG_SYS_LOADS_BAUD_CHANGE:
3345 Enable temporary baudrate change while serial download
3347 - CONFIG_SYS_SDRAM_BASE:
3348 Physical start address of SDRAM. _Must_ be 0 here.
3350 - CONFIG_SYS_FLASH_BASE:
3351 Physical start address of Flash memory.
3353 - CONFIG_SYS_MONITOR_BASE:
3354 Physical start address of boot monitor code (set by
3355 make config files to be same as the text base address
3356 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
3357 CONFIG_SYS_FLASH_BASE when booting from flash.
3359 - CONFIG_SYS_MONITOR_LEN:
3360 Size of memory reserved for monitor code, used to
3361 determine _at_compile_time_ (!) if the environment is
3362 embedded within the U-Boot image, or in a separate
3365 - CONFIG_SYS_MALLOC_LEN:
3366 Size of DRAM reserved for malloc() use.
3368 - CONFIG_SYS_MALLOC_F_LEN
3369 Size of the malloc() pool for use before relocation. If
3370 this is defined, then a very simple malloc() implementation
3371 will become available before relocation. The address is just
3372 below the global data, and the stack is moved down to make
3375 This feature allocates regions with increasing addresses
3376 within the region. calloc() is supported, but realloc()
3377 is not available. free() is supported but does nothing.
3378 The memory will be freed (or in fact just forgotten) when
3379 U-Boot relocates itself.
3381 - CONFIG_SYS_MALLOC_SIMPLE
3382 Provides a simple and small malloc() and calloc() for those
3383 boards which do not use the full malloc in SPL (which is
3384 enabled with CONFIG_SYS_SPL_MALLOC_START).
3386 - CONFIG_SYS_NONCACHED_MEMORY:
3387 Size of non-cached memory area. This area of memory will be
3388 typically located right below the malloc() area and mapped
3389 uncached in the MMU. This is useful for drivers that would
3390 otherwise require a lot of explicit cache maintenance. For
3391 some drivers it's also impossible to properly maintain the
3392 cache. For example if the regions that need to be flushed
3393 are not a multiple of the cache-line size, *and* padding
3394 cannot be allocated between the regions to align them (i.e.
3395 if the HW requires a contiguous array of regions, and the
3396 size of each region is not cache-aligned), then a flush of
3397 one region may result in overwriting data that hardware has
3398 written to another region in the same cache-line. This can
3399 happen for example in network drivers where descriptors for
3400 buffers are typically smaller than the CPU cache-line (e.g.
3401 16 bytes vs. 32 or 64 bytes).
3403 Non-cached memory is only supported on 32-bit ARM at present.
3405 - CONFIG_SYS_BOOTM_LEN:
3406 Normally compressed uImages are limited to an
3407 uncompressed size of 8 MBytes. If this is not enough,
3408 you can define CONFIG_SYS_BOOTM_LEN in your board config file
3409 to adjust this setting to your needs.
3411 - CONFIG_SYS_BOOTMAPSZ:
3412 Maximum size of memory mapped by the startup code of
3413 the Linux kernel; all data that must be processed by
3414 the Linux kernel (bd_info, boot arguments, FDT blob if
3415 used) must be put below this limit, unless "bootm_low"
3416 environment variable is defined and non-zero. In such case
3417 all data for the Linux kernel must be between "bootm_low"
3418 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
3419 variable "bootm_mapsize" will override the value of
3420 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
3421 then the value in "bootm_size" will be used instead.
3423 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
3424 Enable initrd_high functionality. If defined then the
3425 initrd_high feature is enabled and the bootm ramdisk subcommand
3428 - CONFIG_SYS_BOOT_GET_CMDLINE:
3429 Enables allocating and saving kernel cmdline in space between
3430 "bootm_low" and "bootm_low" + BOOTMAPSZ.
3432 - CONFIG_SYS_BOOT_GET_KBD:
3433 Enables allocating and saving a kernel copy of the bd_info in
3434 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
3436 - CONFIG_SYS_MAX_FLASH_BANKS:
3437 Max number of Flash memory banks
3439 - CONFIG_SYS_MAX_FLASH_SECT:
3440 Max number of sectors on a Flash chip
3442 - CONFIG_SYS_FLASH_ERASE_TOUT:
3443 Timeout for Flash erase operations (in ms)
3445 - CONFIG_SYS_FLASH_WRITE_TOUT:
3446 Timeout for Flash write operations (in ms)
3448 - CONFIG_SYS_FLASH_LOCK_TOUT
3449 Timeout for Flash set sector lock bit operation (in ms)
3451 - CONFIG_SYS_FLASH_UNLOCK_TOUT
3452 Timeout for Flash clear lock bits operation (in ms)
3454 - CONFIG_SYS_FLASH_PROTECTION
3455 If defined, hardware flash sectors protection is used
3456 instead of U-Boot software protection.
3458 - CONFIG_SYS_DIRECT_FLASH_TFTP:
3460 Enable TFTP transfers directly to flash memory;
3461 without this option such a download has to be
3462 performed in two steps: (1) download to RAM, and (2)
3463 copy from RAM to flash.
3465 The two-step approach is usually more reliable, since
3466 you can check if the download worked before you erase
3467 the flash, but in some situations (when system RAM is
3468 too limited to allow for a temporary copy of the
3469 downloaded image) this option may be very useful.
3471 - CONFIG_SYS_FLASH_CFI:
3472 Define if the flash driver uses extra elements in the
3473 common flash structure for storing flash geometry.
3475 - CONFIG_FLASH_CFI_DRIVER
3476 This option also enables the building of the cfi_flash driver
3477 in the drivers directory
3479 - CONFIG_FLASH_CFI_MTD
3480 This option enables the building of the cfi_mtd driver
3481 in the drivers directory. The driver exports CFI flash
3484 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
3485 Use buffered writes to flash.
3487 - CONFIG_FLASH_SPANSION_S29WS_N
3488 s29ws-n MirrorBit flash has non-standard addresses for buffered
3491 - CONFIG_SYS_FLASH_QUIET_TEST
3492 If this option is defined, the common CFI flash doesn't
3493 print it's warning upon not recognized FLASH banks. This
3494 is useful, if some of the configured banks are only
3495 optionally available.
3497 - CONFIG_FLASH_SHOW_PROGRESS
3498 If defined (must be an integer), print out countdown
3499 digits and dots. Recommended value: 45 (9..1) for 80
3500 column displays, 15 (3..1) for 40 column displays.
3502 - CONFIG_FLASH_VERIFY
3503 If defined, the content of the flash (destination) is compared
3504 against the source after the write operation. An error message
3505 will be printed when the contents are not identical.
3506 Please note that this option is useless in nearly all cases,
3507 since such flash programming errors usually are detected earlier
3508 while unprotecting/erasing/programming. Please only enable
3509 this option if you really know what you are doing.
3511 - CONFIG_SYS_RX_ETH_BUFFER:
3512 Defines the number of Ethernet receive buffers. On some
3513 Ethernet controllers it is recommended to set this value
3514 to 8 or even higher (EEPRO100 or 405 EMAC), since all
3515 buffers can be full shortly after enabling the interface
3516 on high Ethernet traffic.
3517 Defaults to 4 if not defined.
3519 - CONFIG_ENV_MAX_ENTRIES
3521 Maximum number of entries in the hash table that is used
3522 internally to store the environment settings. The default
3523 setting is supposed to be generous and should work in most
3524 cases. This setting can be used to tune behaviour; see
3525 lib/hashtable.c for details.
3527 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3528 - CONFIG_ENV_FLAGS_LIST_STATIC
3529 Enable validation of the values given to environment variables when
3530 calling env set. Variables can be restricted to only decimal,
3531 hexadecimal, or boolean. If CONFIG_CMD_NET is also defined,
3532 the variables can also be restricted to IP address or MAC address.
3534 The format of the list is:
3535 type_attribute = [s|d|x|b|i|m]
3536 access_attribute = [a|r|o|c]
3537 attributes = type_attribute[access_attribute]
3538 entry = variable_name[:attributes]
3541 The type attributes are:
3542 s - String (default)
3545 b - Boolean ([1yYtT|0nNfF])
3549 The access attributes are:
3555 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3556 Define this to a list (string) to define the ".flags"
3557 environment variable in the default or embedded environment.
3559 - CONFIG_ENV_FLAGS_LIST_STATIC
3560 Define this to a list (string) to define validation that
3561 should be done if an entry is not found in the ".flags"
3562 environment variable. To override a setting in the static
3563 list, simply add an entry for the same variable name to the
3566 If CONFIG_REGEX is defined, the variable_name above is evaluated as a
3567 regular expression. This allows multiple variables to define the same
3568 flags without explicitly listing them for each variable.
3570 - CONFIG_ENV_ACCESS_IGNORE_FORCE
3571 If defined, don't allow the -f switch to env set override variable
3575 If stdint.h is available with your toolchain you can define this
3576 option to enable it. You can provide option 'USE_STDINT=1' when
3577 building U-Boot to enable this.
3579 The following definitions that deal with the placement and management
3580 of environment data (variable area); in general, we support the
3581 following configurations:
3583 - CONFIG_BUILD_ENVCRC:
3585 Builds up envcrc with the target environment so that external utils
3586 may easily extract it and embed it in final U-Boot images.
3588 - CONFIG_ENV_IS_IN_FLASH:
3590 Define this if the environment is in flash memory.
3592 a) The environment occupies one whole flash sector, which is
3593 "embedded" in the text segment with the U-Boot code. This
3594 happens usually with "bottom boot sector" or "top boot
3595 sector" type flash chips, which have several smaller
3596 sectors at the start or the end. For instance, such a
3597 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
3598 such a case you would place the environment in one of the
3599 4 kB sectors - with U-Boot code before and after it. With
3600 "top boot sector" type flash chips, you would put the
3601 environment in one of the last sectors, leaving a gap
3602 between U-Boot and the environment.
3604 - CONFIG_ENV_OFFSET:
3606 Offset of environment data (variable area) to the
3607 beginning of flash memory; for instance, with bottom boot
3608 type flash chips the second sector can be used: the offset
3609 for this sector is given here.
3611 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
3615 This is just another way to specify the start address of
3616 the flash sector containing the environment (instead of
3619 - CONFIG_ENV_SECT_SIZE:
3621 Size of the sector containing the environment.
3624 b) Sometimes flash chips have few, equal sized, BIG sectors.
3625 In such a case you don't want to spend a whole sector for
3630 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
3631 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
3632 of this flash sector for the environment. This saves
3633 memory for the RAM copy of the environment.
3635 It may also save flash memory if you decide to use this
3636 when your environment is "embedded" within U-Boot code,
3637 since then the remainder of the flash sector could be used
3638 for U-Boot code. It should be pointed out that this is
3639 STRONGLY DISCOURAGED from a robustness point of view:
3640 updating the environment in flash makes it always
3641 necessary to erase the WHOLE sector. If something goes
3642 wrong before the contents has been restored from a copy in
3643 RAM, your target system will be dead.
3645 - CONFIG_ENV_ADDR_REDUND
3646 CONFIG_ENV_SIZE_REDUND
3648 These settings describe a second storage area used to hold
3649 a redundant copy of the environment data, so that there is
3650 a valid backup copy in case there is a power failure during
3651 a "saveenv" operation.
3653 BE CAREFUL! Any changes to the flash layout, and some changes to the
3654 source code will make it necessary to adapt <board>/u-boot.lds*
3658 - CONFIG_ENV_IS_IN_NVRAM:
3660 Define this if you have some non-volatile memory device
3661 (NVRAM, battery buffered SRAM) which you want to use for the
3667 These two #defines are used to determine the memory area you
3668 want to use for environment. It is assumed that this memory
3669 can just be read and written to, without any special
3672 BE CAREFUL! The first access to the environment happens quite early
3673 in U-Boot initialization (when we try to get the setting of for the
3674 console baudrate). You *MUST* have mapped your NVRAM area then, or
3677 Please note that even with NVRAM we still use a copy of the
3678 environment in RAM: we could work on NVRAM directly, but we want to
3679 keep settings there always unmodified except somebody uses "saveenv"
3680 to save the current settings.
3683 - CONFIG_ENV_IS_IN_EEPROM:
3685 Use this if you have an EEPROM or similar serial access
3686 device and a driver for it.
3688 - CONFIG_ENV_OFFSET:
3691 These two #defines specify the offset and size of the
3692 environment area within the total memory of your EEPROM.
3694 - CONFIG_SYS_I2C_EEPROM_ADDR:
3695 If defined, specified the chip address of the EEPROM device.
3696 The default address is zero.
3698 - CONFIG_SYS_I2C_EEPROM_BUS:
3699 If defined, specified the i2c bus of the EEPROM device.
3701 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
3702 If defined, the number of bits used to address bytes in a
3703 single page in the EEPROM device. A 64 byte page, for example
3704 would require six bits.
3706 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
3707 If defined, the number of milliseconds to delay between
3708 page writes. The default is zero milliseconds.
3710 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
3711 The length in bytes of the EEPROM memory array address. Note
3712 that this is NOT the chip address length!
3714 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
3715 EEPROM chips that implement "address overflow" are ones
3716 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
3717 address and the extra bits end up in the "chip address" bit
3718 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
3721 Note that we consider the length of the address field to
3722 still be one byte because the extra address bits are hidden
3723 in the chip address.
3725 - CONFIG_SYS_EEPROM_SIZE:
3726 The size in bytes of the EEPROM device.
3728 - CONFIG_ENV_EEPROM_IS_ON_I2C
3729 define this, if you have I2C and SPI activated, and your
3730 EEPROM, which holds the environment, is on the I2C bus.
3732 - CONFIG_I2C_ENV_EEPROM_BUS
3733 if you have an Environment on an EEPROM reached over
3734 I2C muxes, you can define here, how to reach this
3735 EEPROM. For example:
3737 #define CONFIG_I2C_ENV_EEPROM_BUS 1
3739 EEPROM which holds the environment, is reached over
3740 a pca9547 i2c mux with address 0x70, channel 3.
3742 - CONFIG_ENV_IS_IN_DATAFLASH:
3744 Define this if you have a DataFlash memory device which you
3745 want to use for the environment.
3747 - CONFIG_ENV_OFFSET:
3751 These three #defines specify the offset and size of the
3752 environment area within the total memory of your DataFlash placed
3753 at the specified address.
3755 - CONFIG_ENV_IS_IN_SPI_FLASH:
3757 Define this if you have a SPI Flash memory device which you
3758 want to use for the environment.
3760 - CONFIG_ENV_OFFSET:
3763 These two #defines specify the offset and size of the
3764 environment area within the SPI Flash. CONFIG_ENV_OFFSET must be
3765 aligned to an erase sector boundary.
3767 - CONFIG_ENV_SECT_SIZE:
3769 Define the SPI flash's sector size.
3771 - CONFIG_ENV_OFFSET_REDUND (optional):
3773 This setting describes a second storage area of CONFIG_ENV_SIZE
3774 size used to hold a redundant copy of the environment data, so
3775 that there is a valid backup copy in case there is a power failure
3776 during a "saveenv" operation. CONFIG_ENV_OFFSET_REDUND must be
3777 aligned to an erase sector boundary.
3779 - CONFIG_ENV_SPI_BUS (optional):
3780 - CONFIG_ENV_SPI_CS (optional):
3782 Define the SPI bus and chip select. If not defined they will be 0.
3784 - CONFIG_ENV_SPI_MAX_HZ (optional):
3786 Define the SPI max work clock. If not defined then use 1MHz.
3788 - CONFIG_ENV_SPI_MODE (optional):
3790 Define the SPI work mode. If not defined then use SPI_MODE_3.
3792 - CONFIG_ENV_IS_IN_REMOTE:
3794 Define this if you have a remote memory space which you
3795 want to use for the local device's environment.
3800 These two #defines specify the address and size of the
3801 environment area within the remote memory space. The
3802 local device can get the environment from remote memory
3803 space by SRIO or PCIE links.
3805 BE CAREFUL! For some special cases, the local device can not use
3806 "saveenv" command. For example, the local device will get the
3807 environment stored in a remote NOR flash by SRIO or PCIE link,
3808 but it can not erase, write this NOR flash by SRIO or PCIE interface.
3810 - CONFIG_ENV_IS_IN_NAND:
3812 Define this if you have a NAND device which you want to use
3813 for the environment.
3815 - CONFIG_ENV_OFFSET:
3818 These two #defines specify the offset and size of the environment
3819 area within the first NAND device. CONFIG_ENV_OFFSET must be
3820 aligned to an erase block boundary.
3822 - CONFIG_ENV_OFFSET_REDUND (optional):
3824 This setting describes a second storage area of CONFIG_ENV_SIZE
3825 size used to hold a redundant copy of the environment data, so
3826 that there is a valid backup copy in case there is a power failure
3827 during a "saveenv" operation. CONFIG_ENV_OFFSET_REDUND must be
3828 aligned to an erase block boundary.
3830 - CONFIG_ENV_RANGE (optional):
3832 Specifies the length of the region in which the environment
3833 can be written. This should be a multiple of the NAND device's
3834 block size. Specifying a range with more erase blocks than
3835 are needed to hold CONFIG_ENV_SIZE allows bad blocks within
3836 the range to be avoided.
3838 - CONFIG_ENV_OFFSET_OOB (optional):
3840 Enables support for dynamically retrieving the offset of the
3841 environment from block zero's out-of-band data. The
3842 "nand env.oob" command can be used to record this offset.
3843 Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
3844 using CONFIG_ENV_OFFSET_OOB.
3846 - CONFIG_NAND_ENV_DST
3848 Defines address in RAM to which the nand_spl code should copy the
3849 environment. If redundant environment is used, it will be copied to
3850 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
3852 - CONFIG_ENV_IS_IN_UBI:
3854 Define this if you have an UBI volume that you want to use for the
3855 environment. This has the benefit of wear-leveling the environment
3856 accesses, which is important on NAND.
3858 - CONFIG_ENV_UBI_PART:
3860 Define this to a string that is the mtd partition containing the UBI.
3862 - CONFIG_ENV_UBI_VOLUME:
3864 Define this to the name of the volume that you want to store the
3867 - CONFIG_ENV_UBI_VOLUME_REDUND:
3869 Define this to the name of another volume to store a second copy of
3870 the environment in. This will enable redundant environments in UBI.
3871 It is assumed that both volumes are in the same MTD partition.
3873 - CONFIG_UBI_SILENCE_MSG
3874 - CONFIG_UBIFS_SILENCE_MSG
3876 You will probably want to define these to avoid a really noisy system
3877 when storing the env in UBI.
3879 - CONFIG_ENV_IS_IN_FAT:
3880 Define this if you want to use the FAT file system for the environment.
3882 - FAT_ENV_INTERFACE:
3884 Define this to a string that is the name of the block device.
3886 - FAT_ENV_DEVICE_AND_PART:
3888 Define this to a string to specify the partition of the device. It can
3891 "D:P", "D:0", "D", "D:" or "D:auto" (D, P are integers. And P >= 1)
3892 - "D:P": device D partition P. Error occurs if device D has no
3895 - "D" or "D:": device D partition 1 if device D has partition
3896 table, or the whole device D if has no partition
3898 - "D:auto": first partition in device D with bootable flag set.
3899 If none, first valid partition in device D. If no
3900 partition table then means device D.
3904 It's a string of the FAT file name. This file use to store the
3908 This should be defined. Otherwise it cannot save the environment file.
3910 - CONFIG_ENV_IS_IN_MMC:
3912 Define this if you have an MMC device which you want to use for the
3915 - CONFIG_SYS_MMC_ENV_DEV:
3917 Specifies which MMC device the environment is stored in.
3919 - CONFIG_SYS_MMC_ENV_PART (optional):
3921 Specifies which MMC partition the environment is stored in. If not
3922 set, defaults to partition 0, the user area. Common values might be
3923 1 (first MMC boot partition), 2 (second MMC boot partition).
3925 - CONFIG_ENV_OFFSET:
3928 These two #defines specify the offset and size of the environment
3929 area within the specified MMC device.
3931 If offset is positive (the usual case), it is treated as relative to
3932 the start of the MMC partition. If offset is negative, it is treated
3933 as relative to the end of the MMC partition. This can be useful if
3934 your board may be fitted with different MMC devices, which have
3935 different sizes for the MMC partitions, and you always want the
3936 environment placed at the very end of the partition, to leave the
3937 maximum possible space before it, to store other data.
3939 These two values are in units of bytes, but must be aligned to an
3940 MMC sector boundary.
3942 - CONFIG_ENV_OFFSET_REDUND (optional):
3944 Specifies a second storage area, of CONFIG_ENV_SIZE size, used to
3945 hold a redundant copy of the environment data. This provides a
3946 valid backup copy in case the other copy is corrupted, e.g. due
3947 to a power failure during a "saveenv" operation.
3949 This value may also be positive or negative; this is handled in the
3950 same way as CONFIG_ENV_OFFSET.
3952 This value is also in units of bytes, but must also be aligned to
3953 an MMC sector boundary.
3955 - CONFIG_ENV_SIZE_REDUND (optional):
3957 This value need not be set, even when CONFIG_ENV_OFFSET_REDUND is
3958 set. If this value is set, it must be set to the same value as
3961 - CONFIG_SYS_SPI_INIT_OFFSET
3963 Defines offset to the initial SPI buffer area in DPRAM. The
3964 area is used at an early stage (ROM part) if the environment
3965 is configured to reside in the SPI EEPROM: We need a 520 byte
3966 scratch DPRAM area. It is used between the two initialization
3967 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
3968 to be a good choice since it makes it far enough from the
3969 start of the data area as well as from the stack pointer.
3971 Please note that the environment is read-only until the monitor
3972 has been relocated to RAM and a RAM copy of the environment has been
3973 created; also, when using EEPROM you will have to use getenv_f()
3974 until then to read environment variables.
3976 The environment is protected by a CRC32 checksum. Before the monitor
3977 is relocated into RAM, as a result of a bad CRC you will be working
3978 with the compiled-in default environment - *silently*!!! [This is
3979 necessary, because the first environment variable we need is the
3980 "baudrate" setting for the console - if we have a bad CRC, we don't
3981 have any device yet where we could complain.]
3983 Note: once the monitor has been relocated, then it will complain if
3984 the default environment is used; a new CRC is computed as soon as you
3985 use the "saveenv" command to store a valid environment.
3987 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
3988 Echo the inverted Ethernet link state to the fault LED.
3990 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
3991 also needs to be defined.
3993 - CONFIG_SYS_FAULT_MII_ADDR:
3994 MII address of the PHY to check for the Ethernet link state.
3996 - CONFIG_NS16550_MIN_FUNCTIONS:
3997 Define this if you desire to only have use of the NS16550_init
3998 and NS16550_putc functions for the serial driver located at
3999 drivers/serial/ns16550.c. This option is useful for saving
4000 space for already greatly restricted images, including but not
4001 limited to NAND_SPL configurations.
4003 - CONFIG_DISPLAY_BOARDINFO
4004 Display information about the board that U-Boot is running on
4005 when U-Boot starts up. The board function checkboard() is called
4008 - CONFIG_DISPLAY_BOARDINFO_LATE
4009 Similar to the previous option, but display this information
4010 later, once stdio is running and output goes to the LCD, if
4013 - CONFIG_BOARD_SIZE_LIMIT:
4014 Maximum size of the U-Boot image. When defined, the
4015 build system checks that the actual size does not
4018 Low Level (hardware related) configuration options:
4019 ---------------------------------------------------
4021 - CONFIG_SYS_CACHELINE_SIZE:
4022 Cache Line Size of the CPU.
4024 - CONFIG_SYS_DEFAULT_IMMR:
4025 Default address of the IMMR after system reset.
4027 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
4028 and RPXsuper) to be able to adjust the position of
4029 the IMMR register after a reset.
4031 - CONFIG_SYS_CCSRBAR_DEFAULT:
4032 Default (power-on reset) physical address of CCSR on Freescale
4035 - CONFIG_SYS_CCSRBAR:
4036 Virtual address of CCSR. On a 32-bit build, this is typically
4037 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
4039 CONFIG_SYS_DEFAULT_IMMR must also be set to this value,
4040 for cross-platform code that uses that macro instead.
4042 - CONFIG_SYS_CCSRBAR_PHYS:
4043 Physical address of CCSR. CCSR can be relocated to a new
4044 physical address, if desired. In this case, this macro should
4045 be set to that address. Otherwise, it should be set to the
4046 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
4047 is typically relocated on 36-bit builds. It is recommended
4048 that this macro be defined via the _HIGH and _LOW macros:
4050 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
4051 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
4053 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
4054 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
4055 either 0 (32-bit build) or 0xF (36-bit build). This macro is
4056 used in assembly code, so it must not contain typecasts or
4057 integer size suffixes (e.g. "ULL").
4059 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
4060 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
4061 used in assembly code, so it must not contain typecasts or
4062 integer size suffixes (e.g. "ULL").
4064 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
4065 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
4066 forced to a value that ensures that CCSR is not relocated.
4068 - Floppy Disk Support:
4069 CONFIG_SYS_FDC_DRIVE_NUMBER
4071 the default drive number (default value 0)
4073 CONFIG_SYS_ISA_IO_STRIDE
4075 defines the spacing between FDC chipset registers
4078 CONFIG_SYS_ISA_IO_OFFSET
4080 defines the offset of register from address. It
4081 depends on which part of the data bus is connected to
4082 the FDC chipset. (default value 0)
4084 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
4085 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
4088 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
4089 fdc_hw_init() is called at the beginning of the FDC
4090 setup. fdc_hw_init() must be provided by the board
4091 source code. It is used to make hardware-dependent
4095 Most IDE controllers were designed to be connected with PCI
4096 interface. Only few of them were designed for AHB interface.
4097 When software is doing ATA command and data transfer to
4098 IDE devices through IDE-AHB controller, some additional
4099 registers accessing to these kind of IDE-AHB controller
4102 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
4103 DO NOT CHANGE unless you know exactly what you're
4104 doing! (11-4) [MPC8xx/82xx systems only]
4106 - CONFIG_SYS_INIT_RAM_ADDR:
4108 Start address of memory area that can be used for
4109 initial data and stack; please note that this must be
4110 writable memory that is working WITHOUT special
4111 initialization, i. e. you CANNOT use normal RAM which
4112 will become available only after programming the
4113 memory controller and running certain initialization
4116 U-Boot uses the following memory types:
4117 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
4118 - MPC824X: data cache
4119 - PPC4xx: data cache
4121 - CONFIG_SYS_GBL_DATA_OFFSET:
4123 Offset of the initial data structure in the memory
4124 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
4125 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
4126 data is located at the end of the available space
4127 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
4128 GENERATED_GBL_DATA_SIZE), and the initial stack is just
4129 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
4130 CONFIG_SYS_GBL_DATA_OFFSET) downward.
4133 On the MPC824X (or other systems that use the data
4134 cache for initial memory) the address chosen for
4135 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
4136 point to an otherwise UNUSED address space between
4137 the top of RAM and the start of the PCI space.
4139 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
4141 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
4143 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
4145 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
4147 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
4149 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
4151 - CONFIG_SYS_OR_TIMING_SDRAM:
4154 - CONFIG_SYS_MAMR_PTA:
4155 periodic timer for refresh
4157 - CONFIG_SYS_DER: Debug Event Register (37-47)
4159 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
4160 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
4161 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
4162 CONFIG_SYS_BR1_PRELIM:
4163 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
4165 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
4166 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
4167 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
4168 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
4170 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
4171 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
4172 Machine Mode Register and Memory Periodic Timer
4173 Prescaler definitions (SDRAM timing)
4175 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
4176 enable I2C microcode relocation patch (MPC8xx);
4177 define relocation offset in DPRAM [DSP2]
4179 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
4180 enable SMC microcode relocation patch (MPC8xx);
4181 define relocation offset in DPRAM [SMC1]
4183 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
4184 enable SPI microcode relocation patch (MPC8xx);
4185 define relocation offset in DPRAM [SCC4]
4187 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
4188 Offset of the bootmode word in DPRAM used by post
4189 (Power On Self Tests). This definition overrides
4190 #define'd default value in commproc.h resp.
4193 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
4194 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
4195 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
4196 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
4197 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
4198 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
4199 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
4200 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
4201 Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
4203 - CONFIG_PCI_DISABLE_PCIE:
4204 Disable PCI-Express on systems where it is supported but not
4207 - CONFIG_PCI_ENUM_ONLY
4208 Only scan through and get the devices on the buses.
4209 Don't do any setup work, presumably because someone or
4210 something has already done it, and we don't need to do it
4211 a second time. Useful for platforms that are pre-booted
4212 by coreboot or similar.
4214 - CONFIG_PCI_INDIRECT_BRIDGE:
4215 Enable support for indirect PCI bridges.
4218 Chip has SRIO or not
4221 Board has SRIO 1 port available
4224 Board has SRIO 2 port available
4226 - CONFIG_SRIO_PCIE_BOOT_MASTER
4227 Board can support master function for Boot from SRIO and PCIE
4229 - CONFIG_SYS_SRIOn_MEM_VIRT:
4230 Virtual Address of SRIO port 'n' memory region
4232 - CONFIG_SYS_SRIOn_MEM_PHYS:
4233 Physical Address of SRIO port 'n' memory region
4235 - CONFIG_SYS_SRIOn_MEM_SIZE:
4236 Size of SRIO port 'n' memory region
4238 - CONFIG_SYS_NAND_BUSWIDTH_16BIT
4239 Defined to tell the NAND controller that the NAND chip is using
4241 Not all NAND drivers use this symbol.
4242 Example of drivers that use it:
4243 - drivers/mtd/nand/ndfc.c
4244 - drivers/mtd/nand/mxc_nand.c
4246 - CONFIG_SYS_NDFC_EBC0_CFG
4247 Sets the EBC0_CFG register for the NDFC. If not defined
4248 a default value will be used.
4251 Get DDR timing information from an I2C EEPROM. Common
4252 with pluggable memory modules such as SODIMMs
4255 I2C address of the SPD EEPROM
4257 - CONFIG_SYS_SPD_BUS_NUM
4258 If SPD EEPROM is on an I2C bus other than the first
4259 one, specify here. Note that the value must resolve
4260 to something your driver can deal with.
4262 - CONFIG_SYS_DDR_RAW_TIMING
4263 Get DDR timing information from other than SPD. Common with
4264 soldered DDR chips onboard without SPD. DDR raw timing
4265 parameters are extracted from datasheet and hard-coded into
4266 header files or board specific files.
4268 - CONFIG_FSL_DDR_INTERACTIVE
4269 Enable interactive DDR debugging. See doc/README.fsl-ddr.
4271 - CONFIG_FSL_DDR_SYNC_REFRESH
4272 Enable sync of refresh for multiple controllers.
4274 - CONFIG_FSL_DDR_BIST
4275 Enable built-in memory test for Freescale DDR controllers.
4277 - CONFIG_SYS_83XX_DDR_USES_CS0
4278 Only for 83xx systems. If specified, then DDR should
4279 be configured using CS0 and CS1 instead of CS2 and CS3.
4281 - CONFIG_ETHER_ON_FEC[12]
4282 Define to enable FEC[12] on a 8xx series processor.
4284 - CONFIG_FEC[12]_PHY
4285 Define to the hardcoded PHY address which corresponds
4286 to the given FEC; i. e.
4287 #define CONFIG_FEC1_PHY 4
4288 means that the PHY with address 4 is connected to FEC1
4290 When set to -1, means to probe for first available.
4292 - CONFIG_FEC[12]_PHY_NORXERR
4293 The PHY does not have a RXERR line (RMII only).
4294 (so program the FEC to ignore it).
4297 Enable RMII mode for all FECs.
4298 Note that this is a global option, we can't
4299 have one FEC in standard MII mode and another in RMII mode.
4301 - CONFIG_CRC32_VERIFY
4302 Add a verify option to the crc32 command.
4305 => crc32 -v <address> <count> <crc32>
4307 Where address/count indicate a memory area
4308 and crc32 is the correct crc32 which the
4312 Add the "loopw" memory command. This only takes effect if
4313 the memory commands are activated globally (CONFIG_CMD_MEM).
4316 Add the "mdc" and "mwc" memory commands. These are cyclic
4321 This command will print 4 bytes (10,11,12,13) each 500 ms.
4323 => mwc.l 100 12345678 10
4324 This command will write 12345678 to address 100 all 10 ms.
4326 This only takes effect if the memory commands are activated
4327 globally (CONFIG_CMD_MEM).
4329 - CONFIG_SKIP_LOWLEVEL_INIT
4330 [ARM, NDS32, MIPS only] If this variable is defined, then certain
4331 low level initializations (like setting up the memory
4332 controller) are omitted and/or U-Boot does not
4333 relocate itself into RAM.
4335 Normally this variable MUST NOT be defined. The only
4336 exception is when U-Boot is loaded (to RAM) by some
4337 other boot loader or by a debugger which performs
4338 these initializations itself.
4340 - CONFIG_SKIP_LOWLEVEL_INIT_ONLY
4341 [ARM926EJ-S only] This allows just the call to lowlevel_init()
4342 to be skipped. The normal CP15 init (such as enabling the
4343 instruction cache) is still performed.
4346 Modifies the behaviour of start.S when compiling a loader
4347 that is executed before the actual U-Boot. E.g. when
4348 compiling a NAND SPL.
4351 Modifies the behaviour of start.S when compiling a loader
4352 that is executed after the SPL and before the actual U-Boot.
4353 It is loaded by the SPL.
4355 - CONFIG_SYS_MPC85XX_NO_RESETVEC
4356 Only for 85xx systems. If this variable is specified, the section
4357 .resetvec is not kept and the section .bootpg is placed in the
4358 previous 4k of the .text section.
4360 - CONFIG_ARCH_MAP_SYSMEM
4361 Generally U-Boot (and in particular the md command) uses
4362 effective address. It is therefore not necessary to regard
4363 U-Boot address as virtual addresses that need to be translated
4364 to physical addresses. However, sandbox requires this, since
4365 it maintains its own little RAM buffer which contains all
4366 addressable memory. This option causes some memory accesses
4367 to be mapped through map_sysmem() / unmap_sysmem().
4369 - CONFIG_X86_RESET_VECTOR
4370 If defined, the x86 reset vector code is included. This is not
4371 needed when U-Boot is running from Coreboot.
4373 - CONFIG_SPL_AM33XX_ENABLE_RTC32K_OSC:
4374 Enables the RTC32K OSC on AM33xx based plattforms
4376 - CONFIG_SYS_NAND_NO_SUBPAGE_WRITE
4377 Option to disable subpage write in NAND driver
4378 driver that uses this:
4379 drivers/mtd/nand/davinci_nand.c
4381 Freescale QE/FMAN Firmware Support:
4382 -----------------------------------
4384 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
4385 loading of "firmware", which is encoded in the QE firmware binary format.
4386 This firmware often needs to be loaded during U-Boot booting, so macros
4387 are used to identify the storage device (NOR flash, SPI, etc) and the address
4390 - CONFIG_SYS_FMAN_FW_ADDR
4391 The address in the storage device where the FMAN microcode is located. The
4392 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4395 - CONFIG_SYS_QE_FW_ADDR
4396 The address in the storage device where the QE microcode is located. The
4397 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4400 - CONFIG_SYS_QE_FMAN_FW_LENGTH
4401 The maximum possible size of the firmware. The firmware binary format
4402 has a field that specifies the actual size of the firmware, but it
4403 might not be possible to read any part of the firmware unless some
4404 local storage is allocated to hold the entire firmware first.
4406 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
4407 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
4408 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
4409 virtual address in NOR flash.
4411 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
4412 Specifies that QE/FMAN firmware is located in NAND flash.
4413 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
4415 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
4416 Specifies that QE/FMAN firmware is located on the primary SD/MMC
4417 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
4419 - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
4420 Specifies that QE/FMAN firmware is located in the remote (master)
4421 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
4422 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
4423 window->master inbound window->master LAW->the ucode address in
4424 master's memory space.
4426 Freescale Layerscape Management Complex Firmware Support:
4427 ---------------------------------------------------------
4428 The Freescale Layerscape Management Complex (MC) supports the loading of
4430 This firmware often needs to be loaded during U-Boot booting, so macros
4431 are used to identify the storage device (NOR flash, SPI, etc) and the address
4434 - CONFIG_FSL_MC_ENET
4435 Enable the MC driver for Layerscape SoCs.
4437 Freescale Layerscape Debug Server Support:
4438 -------------------------------------------
4439 The Freescale Layerscape Debug Server Support supports the loading of
4440 "Debug Server firmware" and triggering SP boot-rom.
4441 This firmware often needs to be loaded during U-Boot booting.
4443 - CONFIG_SYS_MC_RSV_MEM_ALIGN
4444 Define alignment of reserved memory MC requires
4449 In order to achieve reproducible builds, timestamps used in the U-Boot build
4450 process have to be set to a fixed value.
4452 This is done using the SOURCE_DATE_EPOCH environment variable.
4453 SOURCE_DATE_EPOCH is to be set on the build host's shell, not as a configuration
4454 option for U-Boot or an environment variable in U-Boot.
4456 SOURCE_DATE_EPOCH should be set to a number of seconds since the epoch, in UTC.
4458 Building the Software:
4459 ======================
4461 Building U-Boot has been tested in several native build environments
4462 and in many different cross environments. Of course we cannot support
4463 all possibly existing versions of cross development tools in all
4464 (potentially obsolete) versions. In case of tool chain problems we
4465 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
4466 which is extensively used to build and test U-Boot.
4468 If you are not using a native environment, it is assumed that you
4469 have GNU cross compiling tools available in your path. In this case,
4470 you must set the environment variable CROSS_COMPILE in your shell.
4471 Note that no changes to the Makefile or any other source files are
4472 necessary. For example using the ELDK on a 4xx CPU, please enter:
4474 $ CROSS_COMPILE=ppc_4xx-
4475 $ export CROSS_COMPILE
4477 Note: If you wish to generate Windows versions of the utilities in
4478 the tools directory you can use the MinGW toolchain
4479 (http://www.mingw.org). Set your HOST tools to the MinGW
4480 toolchain and execute 'make tools'. For example:
4482 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
4484 Binaries such as tools/mkimage.exe will be created which can
4485 be executed on computers running Windows.
4487 U-Boot is intended to be simple to build. After installing the
4488 sources you must configure U-Boot for one specific board type. This
4493 where "NAME_defconfig" is the name of one of the existing configu-
4494 rations; see boards.cfg for supported names.
4496 Note: for some board special configuration names may exist; check if
4497 additional information is available from the board vendor; for
4498 instance, the TQM823L systems are available without (standard)
4499 or with LCD support. You can select such additional "features"
4500 when choosing the configuration, i. e.
4502 make TQM823L_defconfig
4503 - will configure for a plain TQM823L, i. e. no LCD support
4505 make TQM823L_LCD_defconfig
4506 - will configure for a TQM823L with U-Boot console on LCD
4511 Finally, type "make all", and you should get some working U-Boot
4512 images ready for download to / installation on your system:
4514 - "u-boot.bin" is a raw binary image
4515 - "u-boot" is an image in ELF binary format
4516 - "u-boot.srec" is in Motorola S-Record format
4518 By default the build is performed locally and the objects are saved
4519 in the source directory. One of the two methods can be used to change
4520 this behavior and build U-Boot to some external directory:
4522 1. Add O= to the make command line invocations:
4524 make O=/tmp/build distclean
4525 make O=/tmp/build NAME_defconfig
4526 make O=/tmp/build all
4528 2. Set environment variable KBUILD_OUTPUT to point to the desired location:
4530 export KBUILD_OUTPUT=/tmp/build
4535 Note that the command line "O=" setting overrides the KBUILD_OUTPUT environment
4539 Please be aware that the Makefiles assume you are using GNU make, so
4540 for instance on NetBSD you might need to use "gmake" instead of
4544 If the system board that you have is not listed, then you will need
4545 to port U-Boot to your hardware platform. To do this, follow these
4548 1. Create a new directory to hold your board specific code. Add any
4549 files you need. In your board directory, you will need at least
4550 the "Makefile" and a "<board>.c".
4551 2. Create a new configuration file "include/configs/<board>.h" for
4553 3. If you're porting U-Boot to a new CPU, then also create a new
4554 directory to hold your CPU specific code. Add any files you need.
4555 4. Run "make <board>_defconfig" with your new name.
4556 5. Type "make", and you should get a working "u-boot.srec" file
4557 to be installed on your target system.
4558 6. Debug and solve any problems that might arise.
4559 [Of course, this last step is much harder than it sounds.]
4562 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
4563 ==============================================================
4565 If you have modified U-Boot sources (for instance added a new board
4566 or support for new devices, a new CPU, etc.) you are expected to
4567 provide feedback to the other developers. The feedback normally takes
4568 the form of a "patch", i. e. a context diff against a certain (latest
4569 official or latest in the git repository) version of U-Boot sources.
4571 But before you submit such a patch, please verify that your modifi-
4572 cation did not break existing code. At least make sure that *ALL* of
4573 the supported boards compile WITHOUT ANY compiler warnings. To do so,
4574 just run the buildman script (tools/buildman/buildman), which will
4575 configure and build U-Boot for ALL supported system. Be warned, this
4576 will take a while. Please see the buildman README, or run 'buildman -H'
4580 See also "U-Boot Porting Guide" below.
4583 Monitor Commands - Overview:
4584 ============================
4586 go - start application at address 'addr'
4587 run - run commands in an environment variable
4588 bootm - boot application image from memory
4589 bootp - boot image via network using BootP/TFTP protocol
4590 bootz - boot zImage from memory
4591 tftpboot- boot image via network using TFTP protocol
4592 and env variables "ipaddr" and "serverip"
4593 (and eventually "gatewayip")
4594 tftpput - upload a file via network using TFTP protocol
4595 rarpboot- boot image via network using RARP/TFTP protocol
4596 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
4597 loads - load S-Record file over serial line
4598 loadb - load binary file over serial line (kermit mode)
4600 mm - memory modify (auto-incrementing)
4601 nm - memory modify (constant address)
4602 mw - memory write (fill)
4604 cmp - memory compare
4605 crc32 - checksum calculation
4606 i2c - I2C sub-system
4607 sspi - SPI utility commands
4608 base - print or set address offset
4609 printenv- print environment variables
4610 setenv - set environment variables
4611 saveenv - save environment variables to persistent storage
4612 protect - enable or disable FLASH write protection
4613 erase - erase FLASH memory
4614 flinfo - print FLASH memory information
4615 nand - NAND memory operations (see doc/README.nand)
4616 bdinfo - print Board Info structure
4617 iminfo - print header information for application image
4618 coninfo - print console devices and informations
4619 ide - IDE sub-system
4620 loop - infinite loop on address range
4621 loopw - infinite write loop on address range
4622 mtest - simple RAM test
4623 icache - enable or disable instruction cache
4624 dcache - enable or disable data cache
4625 reset - Perform RESET of the CPU
4626 echo - echo args to console
4627 version - print monitor version
4628 help - print online help
4629 ? - alias for 'help'
4632 Monitor Commands - Detailed Description:
4633 ========================================
4637 For now: just type "help <command>".
4640 Environment Variables:
4641 ======================
4643 U-Boot supports user configuration using Environment Variables which
4644 can be made persistent by saving to Flash memory.
4646 Environment Variables are set using "setenv", printed using
4647 "printenv", and saved to Flash using "saveenv". Using "setenv"
4648 without a value can be used to delete a variable from the
4649 environment. As long as you don't save the environment you are
4650 working with an in-memory copy. In case the Flash area containing the
4651 environment is erased by accident, a default environment is provided.
4653 Some configuration options can be set using Environment Variables.
4655 List of environment variables (most likely not complete):
4657 baudrate - see CONFIG_BAUDRATE
4659 bootdelay - see CONFIG_BOOTDELAY
4661 bootcmd - see CONFIG_BOOTCOMMAND
4663 bootargs - Boot arguments when booting an RTOS image
4665 bootfile - Name of the image to load with TFTP
4667 bootm_low - Memory range available for image processing in the bootm
4668 command can be restricted. This variable is given as
4669 a hexadecimal number and defines lowest address allowed
4670 for use by the bootm command. See also "bootm_size"
4671 environment variable. Address defined by "bootm_low" is
4672 also the base of the initial memory mapping for the Linux
4673 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
4676 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
4677 This variable is given as a hexadecimal number and it
4678 defines the size of the memory region starting at base
4679 address bootm_low that is accessible by the Linux kernel
4680 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
4681 as the default value if it is defined, and bootm_size is
4684 bootm_size - Memory range available for image processing in the bootm
4685 command can be restricted. This variable is given as
4686 a hexadecimal number and defines the size of the region
4687 allowed for use by the bootm command. See also "bootm_low"
4688 environment variable.
4690 updatefile - Location of the software update file on a TFTP server, used
4691 by the automatic software update feature. Please refer to
4692 documentation in doc/README.update for more details.
4694 autoload - if set to "no" (any string beginning with 'n'),
4695 "bootp" will just load perform a lookup of the
4696 configuration from the BOOTP server, but not try to
4697 load any image using TFTP
4699 autostart - if set to "yes", an image loaded using the "bootp",
4700 "rarpboot", "tftpboot" or "diskboot" commands will
4701 be automatically started (by internally calling
4704 If set to "no", a standalone image passed to the
4705 "bootm" command will be copied to the load address
4706 (and eventually uncompressed), but NOT be started.
4707 This can be used to load and uncompress arbitrary
4710 fdt_high - if set this restricts the maximum address that the
4711 flattened device tree will be copied into upon boot.
4712 For example, if you have a system with 1 GB memory
4713 at physical address 0x10000000, while Linux kernel
4714 only recognizes the first 704 MB as low memory, you
4715 may need to set fdt_high as 0x3C000000 to have the
4716 device tree blob be copied to the maximum address
4717 of the 704 MB low memory, so that Linux kernel can
4718 access it during the boot procedure.
4720 If this is set to the special value 0xFFFFFFFF then
4721 the fdt will not be copied at all on boot. For this
4722 to work it must reside in writable memory, have
4723 sufficient padding on the end of it for u-boot to
4724 add the information it needs into it, and the memory
4725 must be accessible by the kernel.
4727 fdtcontroladdr- if set this is the address of the control flattened
4728 device tree used by U-Boot when CONFIG_OF_CONTROL is
4731 i2cfast - (PPC405GP|PPC405EP only)
4732 if set to 'y' configures Linux I2C driver for fast
4733 mode (400kHZ). This environment variable is used in
4734 initialization code. So, for changes to be effective
4735 it must be saved and board must be reset.
4737 initrd_high - restrict positioning of initrd images:
4738 If this variable is not set, initrd images will be
4739 copied to the highest possible address in RAM; this
4740 is usually what you want since it allows for
4741 maximum initrd size. If for some reason you want to
4742 make sure that the initrd image is loaded below the
4743 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
4744 variable to a value of "no" or "off" or "0".
4745 Alternatively, you can set it to a maximum upper
4746 address to use (U-Boot will still check that it
4747 does not overwrite the U-Boot stack and data).
4749 For instance, when you have a system with 16 MB
4750 RAM, and want to reserve 4 MB from use by Linux,
4751 you can do this by adding "mem=12M" to the value of
4752 the "bootargs" variable. However, now you must make
4753 sure that the initrd image is placed in the first
4754 12 MB as well - this can be done with
4756 setenv initrd_high 00c00000
4758 If you set initrd_high to 0xFFFFFFFF, this is an
4759 indication to U-Boot that all addresses are legal
4760 for the Linux kernel, including addresses in flash
4761 memory. In this case U-Boot will NOT COPY the
4762 ramdisk at all. This may be useful to reduce the
4763 boot time on your system, but requires that this
4764 feature is supported by your Linux kernel.
4766 ipaddr - IP address; needed for tftpboot command
4768 loadaddr - Default load address for commands like "bootp",
4769 "rarpboot", "tftpboot", "loadb" or "diskboot"
4771 loads_echo - see CONFIG_LOADS_ECHO
4773 serverip - TFTP server IP address; needed for tftpboot command
4775 bootretry - see CONFIG_BOOT_RETRY_TIME
4777 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
4779 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
4781 ethprime - controls which interface is used first.
4783 ethact - controls which interface is currently active.
4784 For example you can do the following
4786 => setenv ethact FEC
4787 => ping 192.168.0.1 # traffic sent on FEC
4788 => setenv ethact SCC
4789 => ping 10.0.0.1 # traffic sent on SCC
4791 ethrotate - When set to "no" U-Boot does not go through all
4792 available network interfaces.
4793 It just stays at the currently selected interface.
4795 netretry - When set to "no" each network operation will
4796 either succeed or fail without retrying.
4797 When set to "once" the network operation will
4798 fail when all the available network interfaces
4799 are tried once without success.
4800 Useful on scripts which control the retry operation
4803 npe_ucode - set load address for the NPE microcode
4805 silent_linux - If set then Linux will be told to boot silently, by
4806 changing the console to be empty. If "yes" it will be
4807 made silent. If "no" it will not be made silent. If
4808 unset, then it will be made silent if the U-Boot console
4811 tftpsrcp - If this is set, the value is used for TFTP's
4814 tftpdstp - If this is set, the value is used for TFTP's UDP
4815 destination port instead of the Well Know Port 69.
4817 tftpblocksize - Block size to use for TFTP transfers; if not set,
4818 we use the TFTP server's default block size
4820 tftptimeout - Retransmission timeout for TFTP packets (in milli-
4821 seconds, minimum value is 1000 = 1 second). Defines
4822 when a packet is considered to be lost so it has to
4823 be retransmitted. The default is 5000 = 5 seconds.
4824 Lowering this value may make downloads succeed
4825 faster in networks with high packet loss rates or
4826 with unreliable TFTP servers.
4828 tftptimeoutcountmax - maximum count of TFTP timeouts (no
4829 unit, minimum value = 0). Defines how many timeouts
4830 can happen during a single file transfer before that
4831 transfer is aborted. The default is 10, and 0 means
4832 'no timeouts allowed'. Increasing this value may help
4833 downloads succeed with high packet loss rates, or with
4834 unreliable TFTP servers or client hardware.
4836 vlan - When set to a value < 4095 the traffic over
4837 Ethernet is encapsulated/received over 802.1q
4840 bootpretryperiod - Period during which BOOTP/DHCP sends retries.
4841 Unsigned value, in milliseconds. If not set, the period will
4842 be either the default (28000), or a value based on
4843 CONFIG_NET_RETRY_COUNT, if defined. This value has
4844 precedence over the valu based on CONFIG_NET_RETRY_COUNT.
4846 The following image location variables contain the location of images
4847 used in booting. The "Image" column gives the role of the image and is
4848 not an environment variable name. The other columns are environment
4849 variable names. "File Name" gives the name of the file on a TFTP
4850 server, "RAM Address" gives the location in RAM the image will be
4851 loaded to, and "Flash Location" gives the image's address in NOR
4852 flash or offset in NAND flash.
4854 *Note* - these variables don't have to be defined for all boards, some
4855 boards currently use other variables for these purposes, and some
4856 boards use these variables for other purposes.
4858 Image File Name RAM Address Flash Location
4859 ----- --------- ----------- --------------
4860 u-boot u-boot u-boot_addr_r u-boot_addr
4861 Linux kernel bootfile kernel_addr_r kernel_addr
4862 device tree blob fdtfile fdt_addr_r fdt_addr
4863 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
4865 The following environment variables may be used and automatically
4866 updated by the network boot commands ("bootp" and "rarpboot"),
4867 depending the information provided by your boot server:
4869 bootfile - see above
4870 dnsip - IP address of your Domain Name Server
4871 dnsip2 - IP address of your secondary Domain Name Server
4872 gatewayip - IP address of the Gateway (Router) to use
4873 hostname - Target hostname
4875 netmask - Subnet Mask
4876 rootpath - Pathname of the root filesystem on the NFS server
4877 serverip - see above
4880 There are two special Environment Variables:
4882 serial# - contains hardware identification information such
4883 as type string and/or serial number
4884 ethaddr - Ethernet address
4886 These variables can be set only once (usually during manufacturing of
4887 the board). U-Boot refuses to delete or overwrite these variables
4888 once they have been set once.
4891 Further special Environment Variables:
4893 ver - Contains the U-Boot version string as printed
4894 with the "version" command. This variable is
4895 readonly (see CONFIG_VERSION_VARIABLE).
4898 Please note that changes to some configuration parameters may take
4899 only effect after the next boot (yes, that's just like Windoze :-).
4902 Callback functions for environment variables:
4903 ---------------------------------------------
4905 For some environment variables, the behavior of u-boot needs to change
4906 when their values are changed. This functionality allows functions to
4907 be associated with arbitrary variables. On creation, overwrite, or
4908 deletion, the callback will provide the opportunity for some side
4909 effect to happen or for the change to be rejected.
4911 The callbacks are named and associated with a function using the
4912 U_BOOT_ENV_CALLBACK macro in your board or driver code.
4914 These callbacks are associated with variables in one of two ways. The
4915 static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC
4916 in the board configuration to a string that defines a list of
4917 associations. The list must be in the following format:
4919 entry = variable_name[:callback_name]
4922 If the callback name is not specified, then the callback is deleted.
4923 Spaces are also allowed anywhere in the list.
4925 Callbacks can also be associated by defining the ".callbacks" variable
4926 with the same list format above. Any association in ".callbacks" will
4927 override any association in the static list. You can define
4928 CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the
4929 ".callbacks" environment variable in the default or embedded environment.
4931 If CONFIG_REGEX is defined, the variable_name above is evaluated as a
4932 regular expression. This allows multiple variables to be connected to
4933 the same callback without explicitly listing them all out.
4936 Command Line Parsing:
4937 =====================
4939 There are two different command line parsers available with U-Boot:
4940 the old "simple" one, and the much more powerful "hush" shell:
4942 Old, simple command line parser:
4943 --------------------------------
4945 - supports environment variables (through setenv / saveenv commands)
4946 - several commands on one line, separated by ';'
4947 - variable substitution using "... ${name} ..." syntax
4948 - special characters ('$', ';') can be escaped by prefixing with '\',
4950 setenv bootcmd bootm \${address}
4951 - You can also escape text by enclosing in single apostrophes, for example:
4952 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
4957 - similar to Bourne shell, with control structures like
4958 if...then...else...fi, for...do...done; while...do...done,
4959 until...do...done, ...
4960 - supports environment ("global") variables (through setenv / saveenv
4961 commands) and local shell variables (through standard shell syntax
4962 "name=value"); only environment variables can be used with "run"
4968 (1) If a command line (or an environment variable executed by a "run"
4969 command) contains several commands separated by semicolon, and
4970 one of these commands fails, then the remaining commands will be
4973 (2) If you execute several variables with one call to run (i. e.
4974 calling run with a list of variables as arguments), any failing
4975 command will cause "run" to terminate, i. e. the remaining
4976 variables are not executed.
4978 Note for Redundant Ethernet Interfaces:
4979 =======================================
4981 Some boards come with redundant Ethernet interfaces; U-Boot supports
4982 such configurations and is capable of automatic selection of a
4983 "working" interface when needed. MAC assignment works as follows:
4985 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
4986 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
4987 "eth1addr" (=>eth1), "eth2addr", ...
4989 If the network interface stores some valid MAC address (for instance
4990 in SROM), this is used as default address if there is NO correspon-
4991 ding setting in the environment; if the corresponding environment
4992 variable is set, this overrides the settings in the card; that means:
4994 o If the SROM has a valid MAC address, and there is no address in the
4995 environment, the SROM's address is used.
4997 o If there is no valid address in the SROM, and a definition in the
4998 environment exists, then the value from the environment variable is
5001 o If both the SROM and the environment contain a MAC address, and
5002 both addresses are the same, this MAC address is used.
5004 o If both the SROM and the environment contain a MAC address, and the
5005 addresses differ, the value from the environment is used and a
5008 o If neither SROM nor the environment contain a MAC address, an error
5009 is raised. If CONFIG_NET_RANDOM_ETHADDR is defined, then in this case
5010 a random, locally-assigned MAC is used.
5012 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
5013 will be programmed into hardware as part of the initialization process. This
5014 may be skipped by setting the appropriate 'ethmacskip' environment variable.
5015 The naming convention is as follows:
5016 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
5021 U-Boot is capable of booting (and performing other auxiliary operations on)
5022 images in two formats:
5024 New uImage format (FIT)
5025 -----------------------
5027 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
5028 to Flattened Device Tree). It allows the use of images with multiple
5029 components (several kernels, ramdisks, etc.), with contents protected by
5030 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
5036 Old image format is based on binary files which can be basically anything,
5037 preceded by a special header; see the definitions in include/image.h for
5038 details; basically, the header defines the following image properties:
5040 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
5041 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
5042 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
5043 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
5045 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
5046 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
5047 Currently supported: ARM, AVR32, Intel x86, MIPS, NDS32, Nios II, PowerPC).
5048 * Compression Type (uncompressed, gzip, bzip2)
5054 The header is marked by a special Magic Number, and both the header
5055 and the data portions of the image are secured against corruption by
5062 Although U-Boot should support any OS or standalone application
5063 easily, the main focus has always been on Linux during the design of
5066 U-Boot includes many features that so far have been part of some
5067 special "boot loader" code within the Linux kernel. Also, any
5068 "initrd" images to be used are no longer part of one big Linux image;
5069 instead, kernel and "initrd" are separate images. This implementation
5070 serves several purposes:
5072 - the same features can be used for other OS or standalone
5073 applications (for instance: using compressed images to reduce the
5074 Flash memory footprint)
5076 - it becomes much easier to port new Linux kernel versions because
5077 lots of low-level, hardware dependent stuff are done by U-Boot
5079 - the same Linux kernel image can now be used with different "initrd"
5080 images; of course this also means that different kernel images can
5081 be run with the same "initrd". This makes testing easier (you don't
5082 have to build a new "zImage.initrd" Linux image when you just
5083 change a file in your "initrd"). Also, a field-upgrade of the
5084 software is easier now.
5090 Porting Linux to U-Boot based systems:
5091 ---------------------------------------
5093 U-Boot cannot save you from doing all the necessary modifications to
5094 configure the Linux device drivers for use with your target hardware
5095 (no, we don't intend to provide a full virtual machine interface to
5098 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
5100 Just make sure your machine specific header file (for instance
5101 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
5102 Information structure as we define in include/asm-<arch>/u-boot.h,
5103 and make sure that your definition of IMAP_ADDR uses the same value
5104 as your U-Boot configuration in CONFIG_SYS_IMMR.
5106 Note that U-Boot now has a driver model, a unified model for drivers.
5107 If you are adding a new driver, plumb it into driver model. If there
5108 is no uclass available, you are encouraged to create one. See
5112 Configuring the Linux kernel:
5113 -----------------------------
5115 No specific requirements for U-Boot. Make sure you have some root
5116 device (initial ramdisk, NFS) for your target system.
5119 Building a Linux Image:
5120 -----------------------
5122 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
5123 not used. If you use recent kernel source, a new build target
5124 "uImage" will exist which automatically builds an image usable by
5125 U-Boot. Most older kernels also have support for a "pImage" target,
5126 which was introduced for our predecessor project PPCBoot and uses a
5127 100% compatible format.
5131 make TQM850L_defconfig
5136 The "uImage" build target uses a special tool (in 'tools/mkimage') to
5137 encapsulate a compressed Linux kernel image with header information,
5138 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
5140 * build a standard "vmlinux" kernel image (in ELF binary format):
5142 * convert the kernel into a raw binary image:
5144 ${CROSS_COMPILE}-objcopy -O binary \
5145 -R .note -R .comment \
5146 -S vmlinux linux.bin
5148 * compress the binary image:
5152 * package compressed binary image for U-Boot:
5154 mkimage -A ppc -O linux -T kernel -C gzip \
5155 -a 0 -e 0 -n "Linux Kernel Image" \
5156 -d linux.bin.gz uImage
5159 The "mkimage" tool can also be used to create ramdisk images for use
5160 with U-Boot, either separated from the Linux kernel image, or
5161 combined into one file. "mkimage" encapsulates the images with a 64
5162 byte header containing information about target architecture,
5163 operating system, image type, compression method, entry points, time
5164 stamp, CRC32 checksums, etc.
5166 "mkimage" can be called in two ways: to verify existing images and
5167 print the header information, or to build new images.
5169 In the first form (with "-l" option) mkimage lists the information
5170 contained in the header of an existing U-Boot image; this includes
5171 checksum verification:
5173 tools/mkimage -l image
5174 -l ==> list image header information
5176 The second form (with "-d" option) is used to build a U-Boot image
5177 from a "data file" which is used as image payload:
5179 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
5180 -n name -d data_file image
5181 -A ==> set architecture to 'arch'
5182 -O ==> set operating system to 'os'
5183 -T ==> set image type to 'type'
5184 -C ==> set compression type 'comp'
5185 -a ==> set load address to 'addr' (hex)
5186 -e ==> set entry point to 'ep' (hex)
5187 -n ==> set image name to 'name'
5188 -d ==> use image data from 'datafile'
5190 Right now, all Linux kernels for PowerPC systems use the same load
5191 address (0x00000000), but the entry point address depends on the
5194 - 2.2.x kernels have the entry point at 0x0000000C,
5195 - 2.3.x and later kernels have the entry point at 0x00000000.
5197 So a typical call to build a U-Boot image would read:
5199 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5200 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
5201 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
5202 > examples/uImage.TQM850L
5203 Image Name: 2.4.4 kernel for TQM850L
5204 Created: Wed Jul 19 02:34:59 2000
5205 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5206 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5207 Load Address: 0x00000000
5208 Entry Point: 0x00000000
5210 To verify the contents of the image (or check for corruption):
5212 -> tools/mkimage -l examples/uImage.TQM850L
5213 Image Name: 2.4.4 kernel for TQM850L
5214 Created: Wed Jul 19 02:34:59 2000
5215 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5216 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5217 Load Address: 0x00000000
5218 Entry Point: 0x00000000
5220 NOTE: for embedded systems where boot time is critical you can trade
5221 speed for memory and install an UNCOMPRESSED image instead: this
5222 needs more space in Flash, but boots much faster since it does not
5223 need to be uncompressed:
5225 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
5226 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5227 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
5228 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
5229 > examples/uImage.TQM850L-uncompressed
5230 Image Name: 2.4.4 kernel for TQM850L
5231 Created: Wed Jul 19 02:34:59 2000
5232 Image Type: PowerPC Linux Kernel Image (uncompressed)
5233 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
5234 Load Address: 0x00000000
5235 Entry Point: 0x00000000
5238 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
5239 when your kernel is intended to use an initial ramdisk:
5241 -> tools/mkimage -n 'Simple Ramdisk Image' \
5242 > -A ppc -O linux -T ramdisk -C gzip \
5243 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
5244 Image Name: Simple Ramdisk Image
5245 Created: Wed Jan 12 14:01:50 2000
5246 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5247 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
5248 Load Address: 0x00000000
5249 Entry Point: 0x00000000
5251 The "dumpimage" is a tool to disassemble images built by mkimage. Its "-i"
5252 option performs the converse operation of the mkimage's second form (the "-d"
5253 option). Given an image built by mkimage, the dumpimage extracts a "data file"
5256 tools/dumpimage -i image -T type -p position data_file
5257 -i ==> extract from the 'image' a specific 'data_file'
5258 -T ==> set image type to 'type'
5259 -p ==> 'position' (starting at 0) of the 'data_file' inside the 'image'
5262 Installing a Linux Image:
5263 -------------------------
5265 To downloading a U-Boot image over the serial (console) interface,
5266 you must convert the image to S-Record format:
5268 objcopy -I binary -O srec examples/image examples/image.srec
5270 The 'objcopy' does not understand the information in the U-Boot
5271 image header, so the resulting S-Record file will be relative to
5272 address 0x00000000. To load it to a given address, you need to
5273 specify the target address as 'offset' parameter with the 'loads'
5276 Example: install the image to address 0x40100000 (which on the
5277 TQM8xxL is in the first Flash bank):
5279 => erase 40100000 401FFFFF
5285 ## Ready for S-Record download ...
5286 ~>examples/image.srec
5287 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
5289 15989 15990 15991 15992
5290 [file transfer complete]
5292 ## Start Addr = 0x00000000
5295 You can check the success of the download using the 'iminfo' command;
5296 this includes a checksum verification so you can be sure no data
5297 corruption happened:
5301 ## Checking Image at 40100000 ...
5302 Image Name: 2.2.13 for initrd on TQM850L
5303 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5304 Data Size: 335725 Bytes = 327 kB = 0 MB
5305 Load Address: 00000000
5306 Entry Point: 0000000c
5307 Verifying Checksum ... OK
5313 The "bootm" command is used to boot an application that is stored in
5314 memory (RAM or Flash). In case of a Linux kernel image, the contents
5315 of the "bootargs" environment variable is passed to the kernel as
5316 parameters. You can check and modify this variable using the
5317 "printenv" and "setenv" commands:
5320 => printenv bootargs
5321 bootargs=root=/dev/ram
5323 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5325 => printenv bootargs
5326 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5329 ## Booting Linux kernel at 40020000 ...
5330 Image Name: 2.2.13 for NFS on TQM850L
5331 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5332 Data Size: 381681 Bytes = 372 kB = 0 MB
5333 Load Address: 00000000
5334 Entry Point: 0000000c
5335 Verifying Checksum ... OK
5336 Uncompressing Kernel Image ... OK
5337 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
5338 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5339 time_init: decrementer frequency = 187500000/60
5340 Calibrating delay loop... 49.77 BogoMIPS
5341 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
5344 If you want to boot a Linux kernel with initial RAM disk, you pass
5345 the memory addresses of both the kernel and the initrd image (PPBCOOT
5346 format!) to the "bootm" command:
5348 => imi 40100000 40200000
5350 ## Checking Image at 40100000 ...
5351 Image Name: 2.2.13 for initrd on TQM850L
5352 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5353 Data Size: 335725 Bytes = 327 kB = 0 MB
5354 Load Address: 00000000
5355 Entry Point: 0000000c
5356 Verifying Checksum ... OK
5358 ## Checking Image at 40200000 ...
5359 Image Name: Simple Ramdisk Image
5360 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5361 Data Size: 566530 Bytes = 553 kB = 0 MB
5362 Load Address: 00000000
5363 Entry Point: 00000000
5364 Verifying Checksum ... OK
5366 => bootm 40100000 40200000
5367 ## Booting Linux kernel at 40100000 ...
5368 Image Name: 2.2.13 for initrd on TQM850L
5369 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5370 Data Size: 335725 Bytes = 327 kB = 0 MB
5371 Load Address: 00000000
5372 Entry Point: 0000000c
5373 Verifying Checksum ... OK
5374 Uncompressing Kernel Image ... OK
5375 ## Loading RAMDisk Image at 40200000 ...
5376 Image Name: Simple Ramdisk Image
5377 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5378 Data Size: 566530 Bytes = 553 kB = 0 MB
5379 Load Address: 00000000
5380 Entry Point: 00000000
5381 Verifying Checksum ... OK
5382 Loading Ramdisk ... OK
5383 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
5384 Boot arguments: root=/dev/ram
5385 time_init: decrementer frequency = 187500000/60
5386 Calibrating delay loop... 49.77 BogoMIPS
5388 RAMDISK: Compressed image found at block 0
5389 VFS: Mounted root (ext2 filesystem).
5393 Boot Linux and pass a flat device tree:
5396 First, U-Boot must be compiled with the appropriate defines. See the section
5397 titled "Linux Kernel Interface" above for a more in depth explanation. The
5398 following is an example of how to start a kernel and pass an updated
5404 oft=oftrees/mpc8540ads.dtb
5405 => tftp $oftaddr $oft
5406 Speed: 1000, full duplex
5408 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
5409 Filename 'oftrees/mpc8540ads.dtb'.
5410 Load address: 0x300000
5413 Bytes transferred = 4106 (100a hex)
5414 => tftp $loadaddr $bootfile
5415 Speed: 1000, full duplex
5417 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
5419 Load address: 0x200000
5420 Loading:############
5422 Bytes transferred = 1029407 (fb51f hex)
5427 => bootm $loadaddr - $oftaddr
5428 ## Booting image at 00200000 ...
5429 Image Name: Linux-2.6.17-dirty
5430 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5431 Data Size: 1029343 Bytes = 1005.2 kB
5432 Load Address: 00000000
5433 Entry Point: 00000000
5434 Verifying Checksum ... OK
5435 Uncompressing Kernel Image ... OK
5436 Booting using flat device tree at 0x300000
5437 Using MPC85xx ADS machine description
5438 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
5442 More About U-Boot Image Types:
5443 ------------------------------
5445 U-Boot supports the following image types:
5447 "Standalone Programs" are directly runnable in the environment
5448 provided by U-Boot; it is expected that (if they behave
5449 well) you can continue to work in U-Boot after return from
5450 the Standalone Program.
5451 "OS Kernel Images" are usually images of some Embedded OS which
5452 will take over control completely. Usually these programs
5453 will install their own set of exception handlers, device
5454 drivers, set up the MMU, etc. - this means, that you cannot
5455 expect to re-enter U-Boot except by resetting the CPU.
5456 "RAMDisk Images" are more or less just data blocks, and their
5457 parameters (address, size) are passed to an OS kernel that is
5459 "Multi-File Images" contain several images, typically an OS
5460 (Linux) kernel image and one or more data images like
5461 RAMDisks. This construct is useful for instance when you want
5462 to boot over the network using BOOTP etc., where the boot
5463 server provides just a single image file, but you want to get
5464 for instance an OS kernel and a RAMDisk image.
5466 "Multi-File Images" start with a list of image sizes, each
5467 image size (in bytes) specified by an "uint32_t" in network
5468 byte order. This list is terminated by an "(uint32_t)0".
5469 Immediately after the terminating 0 follow the images, one by
5470 one, all aligned on "uint32_t" boundaries (size rounded up to
5471 a multiple of 4 bytes).
5473 "Firmware Images" are binary images containing firmware (like
5474 U-Boot or FPGA images) which usually will be programmed to
5477 "Script files" are command sequences that will be executed by
5478 U-Boot's command interpreter; this feature is especially
5479 useful when you configure U-Boot to use a real shell (hush)
5480 as command interpreter.
5482 Booting the Linux zImage:
5483 -------------------------
5485 On some platforms, it's possible to boot Linux zImage. This is done
5486 using the "bootz" command. The syntax of "bootz" command is the same
5487 as the syntax of "bootm" command.
5489 Note, defining the CONFIG_SUPPORT_RAW_INITRD allows user to supply
5490 kernel with raw initrd images. The syntax is slightly different, the
5491 address of the initrd must be augmented by it's size, in the following
5492 format: "<initrd addres>:<initrd size>".
5498 One of the features of U-Boot is that you can dynamically load and
5499 run "standalone" applications, which can use some resources of
5500 U-Boot like console I/O functions or interrupt services.
5502 Two simple examples are included with the sources:
5507 'examples/hello_world.c' contains a small "Hello World" Demo
5508 application; it is automatically compiled when you build U-Boot.
5509 It's configured to run at address 0x00040004, so you can play with it
5513 ## Ready for S-Record download ...
5514 ~>examples/hello_world.srec
5515 1 2 3 4 5 6 7 8 9 10 11 ...
5516 [file transfer complete]
5518 ## Start Addr = 0x00040004
5520 => go 40004 Hello World! This is a test.
5521 ## Starting application at 0x00040004 ...
5532 Hit any key to exit ...
5534 ## Application terminated, rc = 0x0
5536 Another example, which demonstrates how to register a CPM interrupt
5537 handler with the U-Boot code, can be found in 'examples/timer.c'.
5538 Here, a CPM timer is set up to generate an interrupt every second.
5539 The interrupt service routine is trivial, just printing a '.'
5540 character, but this is just a demo program. The application can be
5541 controlled by the following keys:
5543 ? - print current values og the CPM Timer registers
5544 b - enable interrupts and start timer
5545 e - stop timer and disable interrupts
5546 q - quit application
5549 ## Ready for S-Record download ...
5550 ~>examples/timer.srec
5551 1 2 3 4 5 6 7 8 9 10 11 ...
5552 [file transfer complete]
5554 ## Start Addr = 0x00040004
5557 ## Starting application at 0x00040004 ...
5560 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
5563 [q, b, e, ?] Set interval 1000000 us
5566 [q, b, e, ?] ........
5567 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
5570 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
5573 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
5576 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
5578 [q, b, e, ?] ...Stopping timer
5580 [q, b, e, ?] ## Application terminated, rc = 0x0
5586 Over time, many people have reported problems when trying to use the
5587 "minicom" terminal emulation program for serial download. I (wd)
5588 consider minicom to be broken, and recommend not to use it. Under
5589 Unix, I recommend to use C-Kermit for general purpose use (and
5590 especially for kermit binary protocol download ("loadb" command), and
5591 use "cu" for S-Record download ("loads" command). See
5592 http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
5593 for help with kermit.
5596 Nevertheless, if you absolutely want to use it try adding this
5597 configuration to your "File transfer protocols" section:
5599 Name Program Name U/D FullScr IO-Red. Multi
5600 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
5601 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
5607 Starting at version 0.9.2, U-Boot supports NetBSD both as host
5608 (build U-Boot) and target system (boots NetBSD/mpc8xx).
5610 Building requires a cross environment; it is known to work on
5611 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
5612 need gmake since the Makefiles are not compatible with BSD make).
5613 Note that the cross-powerpc package does not install include files;
5614 attempting to build U-Boot will fail because <machine/ansi.h> is
5615 missing. This file has to be installed and patched manually:
5617 # cd /usr/pkg/cross/powerpc-netbsd/include
5619 # ln -s powerpc machine
5620 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
5621 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
5623 Native builds *don't* work due to incompatibilities between native
5624 and U-Boot include files.
5626 Booting assumes that (the first part of) the image booted is a
5627 stage-2 loader which in turn loads and then invokes the kernel
5628 proper. Loader sources will eventually appear in the NetBSD source
5629 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
5630 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
5633 Implementation Internals:
5634 =========================
5636 The following is not intended to be a complete description of every
5637 implementation detail. However, it should help to understand the
5638 inner workings of U-Boot and make it easier to port it to custom
5642 Initial Stack, Global Data:
5643 ---------------------------
5645 The implementation of U-Boot is complicated by the fact that U-Boot
5646 starts running out of ROM (flash memory), usually without access to
5647 system RAM (because the memory controller is not initialized yet).
5648 This means that we don't have writable Data or BSS segments, and BSS
5649 is not initialized as zero. To be able to get a C environment working
5650 at all, we have to allocate at least a minimal stack. Implementation
5651 options for this are defined and restricted by the CPU used: Some CPU
5652 models provide on-chip memory (like the IMMR area on MPC8xx and
5653 MPC826x processors), on others (parts of) the data cache can be
5654 locked as (mis-) used as memory, etc.
5656 Chris Hallinan posted a good summary of these issues to the
5657 U-Boot mailing list:
5659 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
5660 From: "Chris Hallinan" <clh@net1plus.com>
5661 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
5664 Correct me if I'm wrong, folks, but the way I understand it
5665 is this: Using DCACHE as initial RAM for Stack, etc, does not
5666 require any physical RAM backing up the cache. The cleverness
5667 is that the cache is being used as a temporary supply of
5668 necessary storage before the SDRAM controller is setup. It's
5669 beyond the scope of this list to explain the details, but you
5670 can see how this works by studying the cache architecture and
5671 operation in the architecture and processor-specific manuals.
5673 OCM is On Chip Memory, which I believe the 405GP has 4K. It
5674 is another option for the system designer to use as an
5675 initial stack/RAM area prior to SDRAM being available. Either
5676 option should work for you. Using CS 4 should be fine if your
5677 board designers haven't used it for something that would
5678 cause you grief during the initial boot! It is frequently not
5681 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
5682 with your processor/board/system design. The default value
5683 you will find in any recent u-boot distribution in
5684 walnut.h should work for you. I'd set it to a value larger
5685 than your SDRAM module. If you have a 64MB SDRAM module, set
5686 it above 400_0000. Just make sure your board has no resources
5687 that are supposed to respond to that address! That code in
5688 start.S has been around a while and should work as is when
5689 you get the config right.
5694 It is essential to remember this, since it has some impact on the C
5695 code for the initialization procedures:
5697 * Initialized global data (data segment) is read-only. Do not attempt
5700 * Do not use any uninitialized global data (or implicitly initialized
5701 as zero data - BSS segment) at all - this is undefined, initiali-
5702 zation is performed later (when relocating to RAM).
5704 * Stack space is very limited. Avoid big data buffers or things like
5707 Having only the stack as writable memory limits means we cannot use
5708 normal global data to share information between the code. But it
5709 turned out that the implementation of U-Boot can be greatly
5710 simplified by making a global data structure (gd_t) available to all
5711 functions. We could pass a pointer to this data as argument to _all_
5712 functions, but this would bloat the code. Instead we use a feature of
5713 the GCC compiler (Global Register Variables) to share the data: we
5714 place a pointer (gd) to the global data into a register which we
5715 reserve for this purpose.
5717 When choosing a register for such a purpose we are restricted by the
5718 relevant (E)ABI specifications for the current architecture, and by
5719 GCC's implementation.
5721 For PowerPC, the following registers have specific use:
5723 R2: reserved for system use
5724 R3-R4: parameter passing and return values
5725 R5-R10: parameter passing
5726 R13: small data area pointer
5730 (U-Boot also uses R12 as internal GOT pointer. r12
5731 is a volatile register so r12 needs to be reset when
5732 going back and forth between asm and C)
5734 ==> U-Boot will use R2 to hold a pointer to the global data
5736 Note: on PPC, we could use a static initializer (since the
5737 address of the global data structure is known at compile time),
5738 but it turned out that reserving a register results in somewhat
5739 smaller code - although the code savings are not that big (on
5740 average for all boards 752 bytes for the whole U-Boot image,
5741 624 text + 127 data).
5743 On ARM, the following registers are used:
5745 R0: function argument word/integer result
5746 R1-R3: function argument word
5747 R9: platform specific
5748 R10: stack limit (used only if stack checking is enabled)
5749 R11: argument (frame) pointer
5750 R12: temporary workspace
5753 R15: program counter
5755 ==> U-Boot will use R9 to hold a pointer to the global data
5757 Note: on ARM, only R_ARM_RELATIVE relocations are supported.
5759 On Nios II, the ABI is documented here:
5760 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
5762 ==> U-Boot will use gp to hold a pointer to the global data
5764 Note: on Nios II, we give "-G0" option to gcc and don't use gp
5765 to access small data sections, so gp is free.
5767 On NDS32, the following registers are used:
5769 R0-R1: argument/return
5771 R15: temporary register for assembler
5772 R16: trampoline register
5773 R28: frame pointer (FP)
5774 R29: global pointer (GP)
5775 R30: link register (LP)
5776 R31: stack pointer (SP)
5777 PC: program counter (PC)
5779 ==> U-Boot will use R10 to hold a pointer to the global data
5781 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
5782 or current versions of GCC may "optimize" the code too much.
5787 U-Boot runs in system state and uses physical addresses, i.e. the
5788 MMU is not used either for address mapping nor for memory protection.
5790 The available memory is mapped to fixed addresses using the memory
5791 controller. In this process, a contiguous block is formed for each
5792 memory type (Flash, SDRAM, SRAM), even when it consists of several
5793 physical memory banks.
5795 U-Boot is installed in the first 128 kB of the first Flash bank (on
5796 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
5797 booting and sizing and initializing DRAM, the code relocates itself
5798 to the upper end of DRAM. Immediately below the U-Boot code some
5799 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
5800 configuration setting]. Below that, a structure with global Board
5801 Info data is placed, followed by the stack (growing downward).
5803 Additionally, some exception handler code is copied to the low 8 kB
5804 of DRAM (0x00000000 ... 0x00001FFF).
5806 So a typical memory configuration with 16 MB of DRAM could look like
5809 0x0000 0000 Exception Vector code
5812 0x0000 2000 Free for Application Use
5818 0x00FB FF20 Monitor Stack (Growing downward)
5819 0x00FB FFAC Board Info Data and permanent copy of global data
5820 0x00FC 0000 Malloc Arena
5823 0x00FE 0000 RAM Copy of Monitor Code
5824 ... eventually: LCD or video framebuffer
5825 ... eventually: pRAM (Protected RAM - unchanged by reset)
5826 0x00FF FFFF [End of RAM]
5829 System Initialization:
5830 ----------------------
5832 In the reset configuration, U-Boot starts at the reset entry point
5833 (on most PowerPC systems at address 0x00000100). Because of the reset
5834 configuration for CS0# this is a mirror of the on board Flash memory.
5835 To be able to re-map memory U-Boot then jumps to its link address.
5836 To be able to implement the initialization code in C, a (small!)
5837 initial stack is set up in the internal Dual Ported RAM (in case CPUs
5838 which provide such a feature like MPC8xx or MPC8260), or in a locked
5839 part of the data cache. After that, U-Boot initializes the CPU core,
5840 the caches and the SIU.
5842 Next, all (potentially) available memory banks are mapped using a
5843 preliminary mapping. For example, we put them on 512 MB boundaries
5844 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
5845 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
5846 programmed for SDRAM access. Using the temporary configuration, a
5847 simple memory test is run that determines the size of the SDRAM
5850 When there is more than one SDRAM bank, and the banks are of
5851 different size, the largest is mapped first. For equal size, the first
5852 bank (CS2#) is mapped first. The first mapping is always for address
5853 0x00000000, with any additional banks following immediately to create
5854 contiguous memory starting from 0.
5856 Then, the monitor installs itself at the upper end of the SDRAM area
5857 and allocates memory for use by malloc() and for the global Board
5858 Info data; also, the exception vector code is copied to the low RAM
5859 pages, and the final stack is set up.
5861 Only after this relocation will you have a "normal" C environment;
5862 until that you are restricted in several ways, mostly because you are
5863 running from ROM, and because the code will have to be relocated to a
5867 U-Boot Porting Guide:
5868 ----------------------
5870 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
5874 int main(int argc, char *argv[])
5876 sighandler_t no_more_time;
5878 signal(SIGALRM, no_more_time);
5879 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
5881 if (available_money > available_manpower) {
5882 Pay consultant to port U-Boot;
5886 Download latest U-Boot source;
5888 Subscribe to u-boot mailing list;
5891 email("Hi, I am new to U-Boot, how do I get started?");
5894 Read the README file in the top level directory;
5895 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
5896 Read applicable doc/*.README;
5897 Read the source, Luke;
5898 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
5901 if (available_money > toLocalCurrency ($2500))
5904 Add a lot of aggravation and time;
5906 if (a similar board exists) { /* hopefully... */
5907 cp -a board/<similar> board/<myboard>
5908 cp include/configs/<similar>.h include/configs/<myboard>.h
5910 Create your own board support subdirectory;
5911 Create your own board include/configs/<myboard>.h file;
5913 Edit new board/<myboard> files
5914 Edit new include/configs/<myboard>.h
5919 Add / modify source code;
5923 email("Hi, I am having problems...");
5925 Send patch file to the U-Boot email list;
5926 if (reasonable critiques)
5927 Incorporate improvements from email list code review;
5929 Defend code as written;
5935 void no_more_time (int sig)
5944 All contributions to U-Boot should conform to the Linux kernel
5945 coding style; see the file "Documentation/CodingStyle" and the script
5946 "scripts/Lindent" in your Linux kernel source directory.
5948 Source files originating from a different project (for example the
5949 MTD subsystem) are generally exempt from these guidelines and are not
5950 reformatted to ease subsequent migration to newer versions of those
5953 Please note that U-Boot is implemented in C (and to some small parts in
5954 Assembler); no C++ is used, so please do not use C++ style comments (//)
5957 Please also stick to the following formatting rules:
5958 - remove any trailing white space
5959 - use TAB characters for indentation and vertical alignment, not spaces
5960 - make sure NOT to use DOS '\r\n' line feeds
5961 - do not add more than 2 consecutive empty lines to source files
5962 - do not add trailing empty lines to source files
5964 Submissions which do not conform to the standards may be returned
5965 with a request to reformat the changes.
5971 Since the number of patches for U-Boot is growing, we need to
5972 establish some rules. Submissions which do not conform to these rules
5973 may be rejected, even when they contain important and valuable stuff.
5975 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
5977 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
5978 see http://lists.denx.de/mailman/listinfo/u-boot
5980 When you send a patch, please include the following information with
5983 * For bug fixes: a description of the bug and how your patch fixes
5984 this bug. Please try to include a way of demonstrating that the
5985 patch actually fixes something.
5987 * For new features: a description of the feature and your
5990 * A CHANGELOG entry as plaintext (separate from the patch)
5992 * For major contributions, add a MAINTAINERS file with your
5993 information and associated file and directory references.
5995 * When you add support for a new board, don't forget to add a
5996 maintainer e-mail address to the boards.cfg file, too.
5998 * If your patch adds new configuration options, don't forget to
5999 document these in the README file.
6001 * The patch itself. If you are using git (which is *strongly*
6002 recommended) you can easily generate the patch using the
6003 "git format-patch". If you then use "git send-email" to send it to
6004 the U-Boot mailing list, you will avoid most of the common problems
6005 with some other mail clients.
6007 If you cannot use git, use "diff -purN OLD NEW". If your version of
6008 diff does not support these options, then get the latest version of
6011 The current directory when running this command shall be the parent
6012 directory of the U-Boot source tree (i. e. please make sure that
6013 your patch includes sufficient directory information for the
6016 We prefer patches as plain text. MIME attachments are discouraged,
6017 and compressed attachments must not be used.
6019 * If one logical set of modifications affects or creates several
6020 files, all these changes shall be submitted in a SINGLE patch file.
6022 * Changesets that contain different, unrelated modifications shall be
6023 submitted as SEPARATE patches, one patch per changeset.
6028 * Before sending the patch, run the buildman script on your patched
6029 source tree and make sure that no errors or warnings are reported
6030 for any of the boards.
6032 * Keep your modifications to the necessary minimum: A patch
6033 containing several unrelated changes or arbitrary reformats will be
6034 returned with a request to re-formatting / split it.
6036 * If you modify existing code, make sure that your new code does not
6037 add to the memory footprint of the code ;-) Small is beautiful!
6038 When adding new features, these should compile conditionally only
6039 (using #ifdef), and the resulting code with the new feature
6040 disabled must not need more memory than the old code without your
6043 * Remember that there is a size limit of 100 kB per message on the
6044 u-boot mailing list. Bigger patches will be moderated. If they are
6045 reasonable and not too big, they will be acknowledged. But patches
6046 bigger than the size limit should be avoided.
projects / platform / kernel / u-boot.git / blob