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 defining 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_CLK * clock command support
830 CONFIG_CMD_CONSOLE coninfo
831 CONFIG_CMD_CRC32 * crc32
832 CONFIG_CMD_DATE * support for RTC, date/time...
833 CONFIG_CMD_DHCP * DHCP support
834 CONFIG_CMD_DIAG * Diagnostics
835 CONFIG_CMD_DS4510 * ds4510 I2C gpio commands
836 CONFIG_CMD_DS4510_INFO * ds4510 I2C info command
837 CONFIG_CMD_DS4510_MEM * ds4510 I2C eeprom/sram commansd
838 CONFIG_CMD_DS4510_RST * ds4510 I2C rst command
839 CONFIG_CMD_DTT * Digital Therm and Thermostat
840 CONFIG_CMD_ECHO echo arguments
841 CONFIG_CMD_EDITENV edit env variable
842 CONFIG_CMD_EEPROM * EEPROM read/write support
843 CONFIG_CMD_EEPROM_LAYOUT* EEPROM layout aware commands
844 CONFIG_CMD_ELF * bootelf, bootvx
845 CONFIG_CMD_ENV_CALLBACK * display details about env callbacks
846 CONFIG_CMD_ENV_FLAGS * display details about env flags
847 CONFIG_CMD_ENV_EXISTS * check existence of env variable
848 CONFIG_CMD_EXPORTENV * export the environment
849 CONFIG_CMD_EXT2 * ext2 command support
850 CONFIG_CMD_EXT4 * ext4 command support
851 CONFIG_CMD_FS_GENERIC * filesystem commands (e.g. load, ls)
852 that work for multiple fs types
853 CONFIG_CMD_FS_UUID * Look up a filesystem UUID
854 CONFIG_CMD_SAVEENV saveenv
855 CONFIG_CMD_FDC * Floppy Disk Support
856 CONFIG_CMD_FAT * FAT command support
857 CONFIG_CMD_FLASH flinfo, erase, protect
858 CONFIG_CMD_FPGA FPGA device initialization support
859 CONFIG_CMD_FUSE * Device fuse support
860 CONFIG_CMD_GETTIME * Get time since boot
861 CONFIG_CMD_GO * the 'go' command (exec code)
862 CONFIG_CMD_GREPENV * search environment
863 CONFIG_CMD_HASH * calculate hash / digest
864 CONFIG_CMD_I2C * I2C serial bus support
865 CONFIG_CMD_IDE * IDE harddisk support
866 CONFIG_CMD_IMI iminfo
867 CONFIG_CMD_IMLS List all images found in NOR flash
868 CONFIG_CMD_IMLS_NAND * List all images found in NAND flash
869 CONFIG_CMD_IMMAP * IMMR dump support
870 CONFIG_CMD_IOTRACE * I/O tracing for debugging
871 CONFIG_CMD_IMPORTENV * import an environment
872 CONFIG_CMD_INI * import data from an ini file into the env
873 CONFIG_CMD_IRQ * irqinfo
874 CONFIG_CMD_ITEST Integer/string test of 2 values
875 CONFIG_CMD_JFFS2 * JFFS2 Support
876 CONFIG_CMD_KGDB * kgdb
877 CONFIG_CMD_LDRINFO * ldrinfo (display Blackfin loader)
878 CONFIG_CMD_LINK_LOCAL * link-local IP address auto-configuration
880 CONFIG_CMD_LOADB loadb
881 CONFIG_CMD_LOADS loads
882 CONFIG_CMD_MD5SUM * print md5 message digest
883 (requires CONFIG_CMD_MEMORY and CONFIG_MD5)
884 CONFIG_CMD_MEMINFO * Display detailed memory information
885 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
887 CONFIG_CMD_MEMTEST * mtest
888 CONFIG_CMD_MISC Misc functions like sleep etc
889 CONFIG_CMD_MMC * MMC memory mapped support
890 CONFIG_CMD_MII * MII utility commands
891 CONFIG_CMD_MTDPARTS * MTD partition support
892 CONFIG_CMD_NAND * NAND support
893 CONFIG_CMD_NET bootp, tftpboot, rarpboot
894 CONFIG_CMD_NFS NFS support
895 CONFIG_CMD_PCA953X * PCA953x I2C gpio commands
896 CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command
897 CONFIG_CMD_PCI * pciinfo
898 CONFIG_CMD_PCMCIA * PCMCIA support
899 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
901 CONFIG_CMD_PORTIO * Port I/O
902 CONFIG_CMD_READ * Read raw data from partition
903 CONFIG_CMD_REGINFO * Register dump
904 CONFIG_CMD_RUN run command in env variable
905 CONFIG_CMD_SANDBOX * sb command to access sandbox features
906 CONFIG_CMD_SAVES * save S record dump
907 CONFIG_SCSI * SCSI Support
908 CONFIG_CMD_SDRAM * print SDRAM configuration information
909 (requires CONFIG_CMD_I2C)
910 CONFIG_CMD_SETGETDCR Support for DCR Register access
912 CONFIG_CMD_SF * Read/write/erase SPI NOR flash
913 CONFIG_CMD_SHA1SUM * print sha1 memory digest
914 (requires CONFIG_CMD_MEMORY)
915 CONFIG_CMD_SOFTSWITCH * Soft switch setting command for BF60x
916 CONFIG_CMD_SOURCE "source" command Support
917 CONFIG_CMD_SPI * SPI serial bus support
918 CONFIG_CMD_TFTPSRV * TFTP transfer in server mode
919 CONFIG_CMD_TFTPPUT * TFTP put command (upload)
920 CONFIG_CMD_TIME * run command and report execution time (ARM specific)
921 CONFIG_CMD_TIMER * access to the system tick timer
922 CONFIG_CMD_USB * USB support
923 CONFIG_CMD_CDP * Cisco Discover Protocol support
924 CONFIG_CMD_MFSL * Microblaze FSL support
925 CONFIG_CMD_XIMG Load part of Multi Image
926 CONFIG_CMD_UUID * Generate random UUID or GUID string
928 EXAMPLE: If you want all functions except of network
929 support you can write:
931 #include "config_cmd_all.h"
932 #undef CONFIG_CMD_NET
935 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
937 Note: Don't enable the "icache" and "dcache" commands
938 (configuration option CONFIG_CMD_CACHE) unless you know
939 what you (and your U-Boot users) are doing. Data
940 cache cannot be enabled on systems like the 8xx or
941 8260 (where accesses to the IMMR region must be
942 uncached), and it cannot be disabled on all other
943 systems where we (mis-) use the data cache to hold an
944 initial stack and some data.
947 XXX - this list needs to get updated!
949 - Removal of commands
950 If no commands are needed to boot, you can disable
951 CONFIG_CMDLINE to remove them. In this case, the command line
952 will not be available, and when U-Boot wants to execute the
953 boot command (on start-up) it will call board_run_command()
954 instead. This can reduce image size significantly for very
955 simple boot procedures.
957 - Regular expression support:
959 If this variable is defined, U-Boot is linked against
960 the SLRE (Super Light Regular Expression) library,
961 which adds regex support to some commands, as for
962 example "env grep" and "setexpr".
966 If this variable is defined, U-Boot will use a device tree
967 to configure its devices, instead of relying on statically
968 compiled #defines in the board file. This option is
969 experimental and only available on a few boards. The device
970 tree is available in the global data as gd->fdt_blob.
972 U-Boot needs to get its device tree from somewhere. This can
973 be done using one of the two options below:
976 If this variable is defined, U-Boot will embed a device tree
977 binary in its image. This device tree file should be in the
978 board directory and called <soc>-<board>.dts. The binary file
979 is then picked up in board_init_f() and made available through
980 the global data structure as gd->blob.
983 If this variable is defined, U-Boot will build a device tree
984 binary. It will be called u-boot.dtb. Architecture-specific
985 code will locate it at run-time. Generally this works by:
987 cat u-boot.bin u-boot.dtb >image.bin
989 and in fact, U-Boot does this for you, creating a file called
990 u-boot-dtb.bin which is useful in the common case. You can
991 still use the individual files if you need something more
996 If this variable is defined, it enables watchdog
997 support for the SoC. There must be support in the SoC
998 specific code for a watchdog. For the 8xx and 8260
999 CPUs, the SIU Watchdog feature is enabled in the SYPCR
1000 register. When supported for a specific SoC is
1001 available, then no further board specific code should
1002 be needed to use it.
1005 When using a watchdog circuitry external to the used
1006 SoC, then define this variable and provide board
1007 specific code for the "hw_watchdog_reset" function.
1009 CONFIG_AT91_HW_WDT_TIMEOUT
1010 specify the timeout in seconds. default 2 seconds.
1013 CONFIG_VERSION_VARIABLE
1014 If this variable is defined, an environment variable
1015 named "ver" is created by U-Boot showing the U-Boot
1016 version as printed by the "version" command.
1017 Any change to this variable will be reverted at the
1022 When CONFIG_CMD_DATE is selected, the type of the RTC
1023 has to be selected, too. Define exactly one of the
1026 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
1027 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
1028 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC
1029 CONFIG_RTC_MC146818 - use MC146818 RTC
1030 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
1031 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
1032 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
1033 CONFIG_RTC_DS1339 - use Maxim, Inc. DS1339 RTC
1034 CONFIG_RTC_DS164x - use Dallas DS164x RTC
1035 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
1036 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
1037 CONFIG_SYS_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
1038 CONFIG_SYS_RV3029_TCR - enable trickle charger on
1041 Note that if the RTC uses I2C, then the I2C interface
1042 must also be configured. See I2C Support, below.
1045 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
1047 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
1048 chip-ngpio pairs that tell the PCA953X driver the number of
1049 pins supported by a particular chip.
1051 Note that if the GPIO device uses I2C, then the I2C interface
1052 must also be configured. See I2C Support, below.
1055 When CONFIG_IO_TRACE is selected, U-Boot intercepts all I/O
1056 accesses and can checksum them or write a list of them out
1057 to memory. See the 'iotrace' command for details. This is
1058 useful for testing device drivers since it can confirm that
1059 the driver behaves the same way before and after a code
1060 change. Currently this is supported on sandbox and arm. To
1061 add support for your architecture, add '#include <iotrace.h>'
1062 to the bottom of arch/<arch>/include/asm/io.h and test.
1064 Example output from the 'iotrace stats' command is below.
1065 Note that if the trace buffer is exhausted, the checksum will
1066 still continue to operate.
1069 Start: 10000000 (buffer start address)
1070 Size: 00010000 (buffer size)
1071 Offset: 00000120 (current buffer offset)
1072 Output: 10000120 (start + offset)
1073 Count: 00000018 (number of trace records)
1074 CRC32: 9526fb66 (CRC32 of all trace records)
1076 - Timestamp Support:
1078 When CONFIG_TIMESTAMP is selected, the timestamp
1079 (date and time) of an image is printed by image
1080 commands like bootm or iminfo. This option is
1081 automatically enabled when you select CONFIG_CMD_DATE .
1083 - Partition Labels (disklabels) Supported:
1084 Zero or more of the following:
1085 CONFIG_MAC_PARTITION Apple's MacOS partition table.
1086 CONFIG_DOS_PARTITION MS Dos partition table, traditional on the
1087 Intel architecture, USB sticks, etc.
1088 CONFIG_ISO_PARTITION ISO partition table, used on CDROM etc.
1089 CONFIG_EFI_PARTITION GPT partition table, common when EFI is the
1090 bootloader. Note 2TB partition limit; see
1092 CONFIG_MTD_PARTITIONS Memory Technology Device partition table.
1094 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
1095 CONFIG_SCSI) you must configure support for at
1096 least one non-MTD partition type as well.
1099 CONFIG_IDE_RESET_ROUTINE - this is defined in several
1100 board configurations files but used nowhere!
1102 CONFIG_IDE_RESET - is this is defined, IDE Reset will
1103 be performed by calling the function
1104 ide_set_reset(int reset)
1105 which has to be defined in a board specific file
1110 Set this to enable ATAPI support.
1115 Set this to enable support for disks larger than 137GB
1116 Also look at CONFIG_SYS_64BIT_LBA.
1117 Whithout these , LBA48 support uses 32bit variables and will 'only'
1118 support disks up to 2.1TB.
1120 CONFIG_SYS_64BIT_LBA:
1121 When enabled, makes the IDE subsystem use 64bit sector addresses.
1125 At the moment only there is only support for the
1126 SYM53C8XX SCSI controller; define
1127 CONFIG_SCSI_SYM53C8XX to enable it.
1129 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
1130 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
1131 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
1132 maximum numbers of LUNs, SCSI ID's and target
1134 CONFIG_SYS_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
1136 The environment variable 'scsidevs' is set to the number of
1137 SCSI devices found during the last scan.
1139 - NETWORK Support (PCI):
1141 Support for Intel 8254x/8257x gigabit chips.
1144 Utility code for direct access to the SPI bus on Intel 8257x.
1145 This does not do anything useful unless you set at least one
1146 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
1148 CONFIG_E1000_SPI_GENERIC
1149 Allow generic access to the SPI bus on the Intel 8257x, for
1150 example with the "sspi" command.
1153 Management command for E1000 devices. When used on devices
1154 with SPI support you can reprogram the EEPROM from U-Boot.
1157 Support for Intel 82557/82559/82559ER chips.
1158 Optional CONFIG_EEPRO100_SROM_WRITE enables EEPROM
1159 write routine for first time initialisation.
1162 Support for Digital 2114x chips.
1163 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
1164 modem chip initialisation (KS8761/QS6611).
1167 Support for National dp83815 chips.
1170 Support for National dp8382[01] gigabit chips.
1172 - NETWORK Support (other):
1174 CONFIG_DRIVER_AT91EMAC
1175 Support for AT91RM9200 EMAC.
1178 Define this to use reduced MII inteface
1180 CONFIG_DRIVER_AT91EMAC_QUIET
1181 If this defined, the driver is quiet.
1182 The driver doen't show link status messages.
1184 CONFIG_CALXEDA_XGMAC
1185 Support for the Calxeda XGMAC device
1188 Support for SMSC's LAN91C96 chips.
1190 CONFIG_LAN91C96_USE_32_BIT
1191 Define this to enable 32 bit addressing
1194 Support for SMSC's LAN91C111 chip
1196 CONFIG_SMC91111_BASE
1197 Define this to hold the physical address
1198 of the device (I/O space)
1200 CONFIG_SMC_USE_32_BIT
1201 Define this if data bus is 32 bits
1203 CONFIG_SMC_USE_IOFUNCS
1204 Define this to use i/o functions instead of macros
1205 (some hardware wont work with macros)
1207 CONFIG_DRIVER_TI_EMAC
1208 Support for davinci emac
1210 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
1211 Define this if you have more then 3 PHYs.
1214 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
1216 CONFIG_FTGMAC100_EGIGA
1217 Define this to use GE link update with gigabit PHY.
1218 Define this if FTGMAC100 is connected to gigabit PHY.
1219 If your system has 10/100 PHY only, it might not occur
1220 wrong behavior. Because PHY usually return timeout or
1221 useless data when polling gigabit status and gigabit
1222 control registers. This behavior won't affect the
1223 correctnessof 10/100 link speed update.
1226 Support for SMSC's LAN911x and LAN921x chips
1229 Define this to hold the physical address
1230 of the device (I/O space)
1232 CONFIG_SMC911X_32_BIT
1233 Define this if data bus is 32 bits
1235 CONFIG_SMC911X_16_BIT
1236 Define this if data bus is 16 bits. If your processor
1237 automatically converts one 32 bit word to two 16 bit
1238 words you may also try CONFIG_SMC911X_32_BIT.
1241 Support for Renesas on-chip Ethernet controller
1243 CONFIG_SH_ETHER_USE_PORT
1244 Define the number of ports to be used
1246 CONFIG_SH_ETHER_PHY_ADDR
1247 Define the ETH PHY's address
1249 CONFIG_SH_ETHER_CACHE_WRITEBACK
1250 If this option is set, the driver enables cache flush.
1254 Support for PWM module on the imx6.
1258 Support TPM devices.
1260 CONFIG_TPM_TIS_INFINEON
1261 Support for Infineon i2c bus TPM devices. Only one device
1262 per system is supported at this time.
1264 CONFIG_TPM_TIS_I2C_BURST_LIMITATION
1265 Define the burst count bytes upper limit
1268 Support for STMicroelectronics TPM devices. Requires DM_TPM support.
1270 CONFIG_TPM_ST33ZP24_I2C
1271 Support for STMicroelectronics ST33ZP24 I2C devices.
1272 Requires TPM_ST33ZP24 and I2C.
1274 CONFIG_TPM_ST33ZP24_SPI
1275 Support for STMicroelectronics ST33ZP24 SPI devices.
1276 Requires TPM_ST33ZP24 and SPI.
1278 CONFIG_TPM_ATMEL_TWI
1279 Support for Atmel TWI TPM device. Requires I2C support.
1282 Support for generic parallel port TPM devices. Only one device
1283 per system is supported at this time.
1285 CONFIG_TPM_TIS_BASE_ADDRESS
1286 Base address where the generic TPM device is mapped
1287 to. Contemporary x86 systems usually map it at
1291 Add tpm monitor functions.
1292 Requires CONFIG_TPM. If CONFIG_TPM_AUTH_SESSIONS is set, also
1293 provides monitor access to authorized functions.
1296 Define this to enable the TPM support library which provides
1297 functional interfaces to some TPM commands.
1298 Requires support for a TPM device.
1300 CONFIG_TPM_AUTH_SESSIONS
1301 Define this to enable authorized functions in the TPM library.
1302 Requires CONFIG_TPM and CONFIG_SHA1.
1305 At the moment only the UHCI host controller is
1306 supported (PIP405, MIP405, MPC5200); define
1307 CONFIG_USB_UHCI to enable it.
1308 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
1309 and define CONFIG_USB_STORAGE to enable the USB
1312 Supported are USB Keyboards and USB Floppy drives
1314 MPC5200 USB requires additional defines:
1316 for 528 MHz Clock: 0x0001bbbb
1320 for differential drivers: 0x00001000
1321 for single ended drivers: 0x00005000
1322 for differential drivers on PSC3: 0x00000100
1323 for single ended drivers on PSC3: 0x00004100
1324 CONFIG_SYS_USB_EVENT_POLL
1325 May be defined to allow interrupt polling
1326 instead of using asynchronous interrupts
1328 CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
1329 txfilltuning field in the EHCI controller on reset.
1331 CONFIG_USB_DWC2_REG_ADDR the physical CPU address of the DWC2
1332 HW module registers.
1335 Define the below if you wish to use the USB console.
1336 Once firmware is rebuilt from a serial console issue the
1337 command "setenv stdin usbtty; setenv stdout usbtty" and
1338 attach your USB cable. The Unix command "dmesg" should print
1339 it has found a new device. The environment variable usbtty
1340 can be set to gserial or cdc_acm to enable your device to
1341 appear to a USB host as a Linux gserial device or a
1342 Common Device Class Abstract Control Model serial device.
1343 If you select usbtty = gserial you should be able to enumerate
1345 # modprobe usbserial vendor=0xVendorID product=0xProductID
1346 else if using cdc_acm, simply setting the environment
1347 variable usbtty to be cdc_acm should suffice. The following
1348 might be defined in YourBoardName.h
1351 Define this to build a UDC device
1354 Define this to have a tty type of device available to
1355 talk to the UDC device
1358 Define this to enable the high speed support for usb
1359 device and usbtty. If this feature is enabled, a routine
1360 int is_usbd_high_speed(void)
1361 also needs to be defined by the driver to dynamically poll
1362 whether the enumeration has succeded at high speed or full
1365 CONFIG_SYS_CONSOLE_IS_IN_ENV
1366 Define this if you want stdin, stdout &/or stderr to
1370 CONFIG_SYS_USB_EXTC_CLK 0xBLAH
1371 Derive USB clock from external clock "blah"
1372 - CONFIG_SYS_USB_EXTC_CLK 0x02
1374 If you have a USB-IF assigned VendorID then you may wish to
1375 define your own vendor specific values either in BoardName.h
1376 or directly in usbd_vendor_info.h. If you don't define
1377 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
1378 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
1379 should pretend to be a Linux device to it's target host.
1381 CONFIG_USBD_MANUFACTURER
1382 Define this string as the name of your company for
1383 - CONFIG_USBD_MANUFACTURER "my company"
1385 CONFIG_USBD_PRODUCT_NAME
1386 Define this string as the name of your product
1387 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
1389 CONFIG_USBD_VENDORID
1390 Define this as your assigned Vendor ID from the USB
1391 Implementors Forum. This *must* be a genuine Vendor ID
1392 to avoid polluting the USB namespace.
1393 - CONFIG_USBD_VENDORID 0xFFFF
1395 CONFIG_USBD_PRODUCTID
1396 Define this as the unique Product ID
1398 - CONFIG_USBD_PRODUCTID 0xFFFF
1400 - ULPI Layer Support:
1401 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
1402 the generic ULPI layer. The generic layer accesses the ULPI PHY
1403 via the platform viewport, so you need both the genric layer and
1404 the viewport enabled. Currently only Chipidea/ARC based
1405 viewport is supported.
1406 To enable the ULPI layer support, define CONFIG_USB_ULPI and
1407 CONFIG_USB_ULPI_VIEWPORT in your board configuration file.
1408 If your ULPI phy needs a different reference clock than the
1409 standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to
1410 the appropriate value in Hz.
1413 The MMC controller on the Intel PXA is supported. To
1414 enable this define CONFIG_MMC. The MMC can be
1415 accessed from the boot prompt by mapping the device
1416 to physical memory similar to flash. Command line is
1417 enabled with CONFIG_CMD_MMC. The MMC driver also works with
1418 the FAT fs. This is enabled with CONFIG_CMD_FAT.
1421 Support for Renesas on-chip MMCIF controller
1423 CONFIG_SH_MMCIF_ADDR
1424 Define the base address of MMCIF registers
1427 Define the clock frequency for MMCIF
1429 CONFIG_SUPPORT_EMMC_BOOT
1430 Enable some additional features of the eMMC boot partitions.
1432 CONFIG_SUPPORT_EMMC_RPMB
1433 Enable the commands for reading, writing and programming the
1434 key for the Replay Protection Memory Block partition in eMMC.
1436 - USB Device Firmware Update (DFU) class support:
1437 CONFIG_USB_FUNCTION_DFU
1438 This enables the USB portion of the DFU USB class
1441 This enables the command "dfu" which is used to have
1442 U-Boot create a DFU class device via USB. This command
1443 requires that the "dfu_alt_info" environment variable be
1444 set and define the alt settings to expose to the host.
1447 This enables support for exposing (e)MMC devices via DFU.
1450 This enables support for exposing NAND devices via DFU.
1453 This enables support for exposing RAM via DFU.
1454 Note: DFU spec refer to non-volatile memory usage, but
1455 allow usages beyond the scope of spec - here RAM usage,
1456 one that would help mostly the developer.
1458 CONFIG_SYS_DFU_DATA_BUF_SIZE
1459 Dfu transfer uses a buffer before writing data to the
1460 raw storage device. Make the size (in bytes) of this buffer
1461 configurable. The size of this buffer is also configurable
1462 through the "dfu_bufsiz" environment variable.
1464 CONFIG_SYS_DFU_MAX_FILE_SIZE
1465 When updating files rather than the raw storage device,
1466 we use a static buffer to copy the file into and then write
1467 the buffer once we've been given the whole file. Define
1468 this to the maximum filesize (in bytes) for the buffer.
1469 Default is 4 MiB if undefined.
1471 DFU_DEFAULT_POLL_TIMEOUT
1472 Poll timeout [ms], is the timeout a device can send to the
1473 host. The host must wait for this timeout before sending
1474 a subsequent DFU_GET_STATUS request to the device.
1476 DFU_MANIFEST_POLL_TIMEOUT
1477 Poll timeout [ms], which the device sends to the host when
1478 entering dfuMANIFEST state. Host waits this timeout, before
1479 sending again an USB request to the device.
1481 - USB Device Android Fastboot support:
1482 CONFIG_USB_FUNCTION_FASTBOOT
1483 This enables the USB part of the fastboot gadget
1486 This enables the command "fastboot" which enables the Android
1487 fastboot mode for the platform's USB device. Fastboot is a USB
1488 protocol for downloading images, flashing and device control
1489 used on Android devices.
1490 See doc/README.android-fastboot for more information.
1492 CONFIG_ANDROID_BOOT_IMAGE
1493 This enables support for booting images which use the Android
1494 image format header.
1496 CONFIG_FASTBOOT_BUF_ADDR
1497 The fastboot protocol requires a large memory buffer for
1498 downloads. Define this to the starting RAM address to use for
1501 CONFIG_FASTBOOT_BUF_SIZE
1502 The fastboot protocol requires a large memory buffer for
1503 downloads. This buffer should be as large as possible for a
1504 platform. Define this to the size available RAM for fastboot.
1506 CONFIG_FASTBOOT_FLASH
1507 The fastboot protocol includes a "flash" command for writing
1508 the downloaded image to a non-volatile storage device. Define
1509 this to enable the "fastboot flash" command.
1511 CONFIG_FASTBOOT_FLASH_MMC_DEV
1512 The fastboot "flash" command requires additional information
1513 regarding the non-volatile storage device. Define this to
1514 the eMMC device that fastboot should use to store the image.
1516 CONFIG_FASTBOOT_GPT_NAME
1517 The fastboot "flash" command supports writing the downloaded
1518 image to the Protective MBR and the Primary GUID Partition
1519 Table. (Additionally, this downloaded image is post-processed
1520 to generate and write the Backup GUID Partition Table.)
1521 This occurs when the specified "partition name" on the
1522 "fastboot flash" command line matches this value.
1523 The default is "gpt" if undefined.
1525 CONFIG_FASTBOOT_MBR_NAME
1526 The fastboot "flash" command supports writing the downloaded
1528 This occurs when the "partition name" specified on the
1529 "fastboot flash" command line matches this value.
1530 If not defined the default value "mbr" is used.
1532 - Journaling Flash filesystem support:
1534 Define these for a default partition on a NAND device
1536 CONFIG_SYS_JFFS2_FIRST_SECTOR,
1537 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
1538 Define these for a default partition on a NOR device
1540 - FAT(File Allocation Table) filesystem write function support:
1543 Define this to enable support for saving memory data as a
1544 file in FAT formatted partition.
1546 This will also enable the command "fatwrite" enabling the
1547 user to write files to FAT.
1549 - CBFS (Coreboot Filesystem) support:
1552 Define this to enable support for reading from a Coreboot
1553 filesystem. Available commands are cbfsinit, cbfsinfo, cbfsls
1556 - FAT(File Allocation Table) filesystem cluster size:
1557 CONFIG_FS_FAT_MAX_CLUSTSIZE
1559 Define the max cluster size for fat operations else
1560 a default value of 65536 will be defined.
1563 See Kconfig help for available keyboard drivers.
1567 Define this to enable a custom keyboard support.
1568 This simply calls drv_keyboard_init() which must be
1569 defined in your board-specific files. This option is deprecated
1570 and is only used by novena. For new boards, use driver model
1575 Enable the Freescale DIU video driver. Reference boards for
1576 SOCs that have a DIU should define this macro to enable DIU
1577 support, and should also define these other macros:
1582 CONFIG_VIDEO_SW_CURSOR
1583 CONFIG_VGA_AS_SINGLE_DEVICE
1585 CONFIG_VIDEO_BMP_LOGO
1587 The DIU driver will look for the 'video-mode' environment
1588 variable, and if defined, enable the DIU as a console during
1589 boot. See the documentation file doc/README.video for a
1590 description of this variable.
1592 - LCD Support: CONFIG_LCD
1594 Define this to enable LCD support (for output to LCD
1595 display); also select one of the supported displays
1596 by defining one of these:
1600 HITACHI TX09D70VM1CCA, 3.5", 240x320.
1602 CONFIG_NEC_NL6448AC33:
1604 NEC NL6448AC33-18. Active, color, single scan.
1606 CONFIG_NEC_NL6448BC20
1608 NEC NL6448BC20-08. 6.5", 640x480.
1609 Active, color, single scan.
1611 CONFIG_NEC_NL6448BC33_54
1613 NEC NL6448BC33-54. 10.4", 640x480.
1614 Active, color, single scan.
1618 Sharp 320x240. Active, color, single scan.
1619 It isn't 16x9, and I am not sure what it is.
1621 CONFIG_SHARP_LQ64D341
1623 Sharp LQ64D341 display, 640x480.
1624 Active, color, single scan.
1628 HLD1045 display, 640x480.
1629 Active, color, single scan.
1633 Optrex CBL50840-2 NF-FW 99 22 M5
1635 Hitachi LMG6912RPFC-00T
1639 320x240. Black & white.
1641 Normally display is black on white background; define
1642 CONFIG_SYS_WHITE_ON_BLACK to get it inverted.
1644 CONFIG_LCD_ALIGNMENT
1646 Normally the LCD is page-aligned (typically 4KB). If this is
1647 defined then the LCD will be aligned to this value instead.
1648 For ARM it is sometimes useful to use MMU_SECTION_SIZE
1649 here, since it is cheaper to change data cache settings on
1650 a per-section basis.
1655 Sometimes, for example if the display is mounted in portrait
1656 mode or even if it's mounted landscape but rotated by 180degree,
1657 we need to rotate our content of the display relative to the
1658 framebuffer, so that user can read the messages which are
1660 Once CONFIG_LCD_ROTATION is defined, the lcd_console will be
1661 initialized with a given rotation from "vl_rot" out of
1662 "vidinfo_t" which is provided by the board specific code.
1663 The value for vl_rot is coded as following (matching to
1664 fbcon=rotate:<n> linux-kernel commandline):
1665 0 = no rotation respectively 0 degree
1666 1 = 90 degree rotation
1667 2 = 180 degree rotation
1668 3 = 270 degree rotation
1670 If CONFIG_LCD_ROTATION is not defined, the console will be
1671 initialized with 0degree rotation.
1675 Support drawing of RLE8-compressed bitmaps on the LCD.
1679 Enables an 'i2c edid' command which can read EDID
1680 information over I2C from an attached LCD display.
1682 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1684 If this option is set, the environment is checked for
1685 a variable "splashimage". If found, the usual display
1686 of logo, copyright and system information on the LCD
1687 is suppressed and the BMP image at the address
1688 specified in "splashimage" is loaded instead. The
1689 console is redirected to the "nulldev", too. This
1690 allows for a "silent" boot where a splash screen is
1691 loaded very quickly after power-on.
1693 CONFIG_SPLASHIMAGE_GUARD
1695 If this option is set, then U-Boot will prevent the environment
1696 variable "splashimage" from being set to a problematic address
1697 (see doc/README.displaying-bmps).
1698 This option is useful for targets where, due to alignment
1699 restrictions, an improperly aligned BMP image will cause a data
1700 abort. If you think you will not have problems with unaligned
1701 accesses (for example because your toolchain prevents them)
1702 there is no need to set this option.
1704 CONFIG_SPLASH_SCREEN_ALIGN
1706 If this option is set the splash image can be freely positioned
1707 on the screen. Environment variable "splashpos" specifies the
1708 position as "x,y". If a positive number is given it is used as
1709 number of pixel from left/top. If a negative number is given it
1710 is used as number of pixel from right/bottom. You can also
1711 specify 'm' for centering the image.
1714 setenv splashpos m,m
1715 => image at center of screen
1717 setenv splashpos 30,20
1718 => image at x = 30 and y = 20
1720 setenv splashpos -10,m
1721 => vertically centered image
1722 at x = dspWidth - bmpWidth - 9
1724 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1726 If this option is set, additionally to standard BMP
1727 images, gzipped BMP images can be displayed via the
1728 splashscreen support or the bmp command.
1730 - Run length encoded BMP image (RLE8) support: CONFIG_VIDEO_BMP_RLE8
1732 If this option is set, 8-bit RLE compressed BMP images
1733 can be displayed via the splashscreen support or the
1736 - Compression support:
1739 Enabled by default to support gzip compressed images.
1743 If this option is set, support for bzip2 compressed
1744 images is included. If not, only uncompressed and gzip
1745 compressed images are supported.
1747 NOTE: the bzip2 algorithm requires a lot of RAM, so
1748 the malloc area (as defined by CONFIG_SYS_MALLOC_LEN) should
1753 If this option is set, support for lzma compressed
1756 Note: The LZMA algorithm adds between 2 and 4KB of code and it
1757 requires an amount of dynamic memory that is given by the
1760 (1846 + 768 << (lc + lp)) * sizeof(uint16)
1762 Where lc and lp stand for, respectively, Literal context bits
1763 and Literal pos bits.
1765 This value is upper-bounded by 14MB in the worst case. Anyway,
1766 for a ~4MB large kernel image, we have lc=3 and lp=0 for a
1767 total amount of (1846 + 768 << (3 + 0)) * 2 = ~41KB... that is
1768 a very small buffer.
1770 Use the lzmainfo tool to determinate the lc and lp values and
1771 then calculate the amount of needed dynamic memory (ensuring
1772 the appropriate CONFIG_SYS_MALLOC_LEN value).
1776 If this option is set, support for LZO compressed images
1782 The address of PHY on MII bus.
1784 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1786 The clock frequency of the MII bus
1790 If this option is set, support for speed/duplex
1791 detection of gigabit PHY is included.
1793 CONFIG_PHY_RESET_DELAY
1795 Some PHY like Intel LXT971A need extra delay after
1796 reset before any MII register access is possible.
1797 For such PHY, set this option to the usec delay
1798 required. (minimum 300usec for LXT971A)
1800 CONFIG_PHY_CMD_DELAY (ppc4xx)
1802 Some PHY like Intel LXT971A need extra delay after
1803 command issued before MII status register can be read
1808 Define a default value for the IP address to use for
1809 the default Ethernet interface, in case this is not
1810 determined through e.g. bootp.
1811 (Environment variable "ipaddr")
1813 - Server IP address:
1816 Defines a default value for the IP address of a TFTP
1817 server to contact when using the "tftboot" command.
1818 (Environment variable "serverip")
1820 CONFIG_KEEP_SERVERADDR
1822 Keeps the server's MAC address, in the env 'serveraddr'
1823 for passing to bootargs (like Linux's netconsole option)
1825 - Gateway IP address:
1828 Defines a default value for the IP address of the
1829 default router where packets to other networks are
1831 (Environment variable "gatewayip")
1836 Defines a default value for the subnet mask (or
1837 routing prefix) which is used to determine if an IP
1838 address belongs to the local subnet or needs to be
1839 forwarded through a router.
1840 (Environment variable "netmask")
1842 - Multicast TFTP Mode:
1845 Defines whether you want to support multicast TFTP as per
1846 rfc-2090; for example to work with atftp. Lets lots of targets
1847 tftp down the same boot image concurrently. Note: the Ethernet
1848 driver in use must provide a function: mcast() to join/leave a
1851 - BOOTP Recovery Mode:
1852 CONFIG_BOOTP_RANDOM_DELAY
1854 If you have many targets in a network that try to
1855 boot using BOOTP, you may want to avoid that all
1856 systems send out BOOTP requests at precisely the same
1857 moment (which would happen for instance at recovery
1858 from a power failure, when all systems will try to
1859 boot, thus flooding the BOOTP server. Defining
1860 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1861 inserted before sending out BOOTP requests. The
1862 following delays are inserted then:
1864 1st BOOTP request: delay 0 ... 1 sec
1865 2nd BOOTP request: delay 0 ... 2 sec
1866 3rd BOOTP request: delay 0 ... 4 sec
1868 BOOTP requests: delay 0 ... 8 sec
1870 CONFIG_BOOTP_ID_CACHE_SIZE
1872 BOOTP packets are uniquely identified using a 32-bit ID. The
1873 server will copy the ID from client requests to responses and
1874 U-Boot will use this to determine if it is the destination of
1875 an incoming response. Some servers will check that addresses
1876 aren't in use before handing them out (usually using an ARP
1877 ping) and therefore take up to a few hundred milliseconds to
1878 respond. Network congestion may also influence the time it
1879 takes for a response to make it back to the client. If that
1880 time is too long, U-Boot will retransmit requests. In order
1881 to allow earlier responses to still be accepted after these
1882 retransmissions, U-Boot's BOOTP client keeps a small cache of
1883 IDs. The CONFIG_BOOTP_ID_CACHE_SIZE controls the size of this
1884 cache. The default is to keep IDs for up to four outstanding
1885 requests. Increasing this will allow U-Boot to accept offers
1886 from a BOOTP client in networks with unusually high latency.
1888 - DHCP Advanced Options:
1889 You can fine tune the DHCP functionality by defining
1890 CONFIG_BOOTP_* symbols:
1892 CONFIG_BOOTP_SUBNETMASK
1893 CONFIG_BOOTP_GATEWAY
1894 CONFIG_BOOTP_HOSTNAME
1895 CONFIG_BOOTP_NISDOMAIN
1896 CONFIG_BOOTP_BOOTPATH
1897 CONFIG_BOOTP_BOOTFILESIZE
1900 CONFIG_BOOTP_SEND_HOSTNAME
1901 CONFIG_BOOTP_NTPSERVER
1902 CONFIG_BOOTP_TIMEOFFSET
1903 CONFIG_BOOTP_VENDOREX
1904 CONFIG_BOOTP_MAY_FAIL
1906 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1907 environment variable, not the BOOTP server.
1909 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
1910 after the configured retry count, the call will fail
1911 instead of starting over. This can be used to fail over
1912 to Link-local IP address configuration if the DHCP server
1915 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1916 serverip from a DHCP server, it is possible that more
1917 than one DNS serverip is offered to the client.
1918 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1919 serverip will be stored in the additional environment
1920 variable "dnsip2". The first DNS serverip is always
1921 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1924 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1925 to do a dynamic update of a DNS server. To do this, they
1926 need the hostname of the DHCP requester.
1927 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1928 of the "hostname" environment variable is passed as
1929 option 12 to the DHCP server.
1931 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1933 A 32bit value in microseconds for a delay between
1934 receiving a "DHCP Offer" and sending the "DHCP Request".
1935 This fixes a problem with certain DHCP servers that don't
1936 respond 100% of the time to a "DHCP request". E.g. On an
1937 AT91RM9200 processor running at 180MHz, this delay needed
1938 to be *at least* 15,000 usec before a Windows Server 2003
1939 DHCP server would reply 100% of the time. I recommend at
1940 least 50,000 usec to be safe. The alternative is to hope
1941 that one of the retries will be successful but note that
1942 the DHCP timeout and retry process takes a longer than
1945 - Link-local IP address negotiation:
1946 Negotiate with other link-local clients on the local network
1947 for an address that doesn't require explicit configuration.
1948 This is especially useful if a DHCP server cannot be guaranteed
1949 to exist in all environments that the device must operate.
1951 See doc/README.link-local for more information.
1954 CONFIG_CDP_DEVICE_ID
1956 The device id used in CDP trigger frames.
1958 CONFIG_CDP_DEVICE_ID_PREFIX
1960 A two character string which is prefixed to the MAC address
1965 A printf format string which contains the ascii name of
1966 the port. Normally is set to "eth%d" which sets
1967 eth0 for the first Ethernet, eth1 for the second etc.
1969 CONFIG_CDP_CAPABILITIES
1971 A 32bit integer which indicates the device capabilities;
1972 0x00000010 for a normal host which does not forwards.
1976 An ascii string containing the version of the software.
1980 An ascii string containing the name of the platform.
1984 A 32bit integer sent on the trigger.
1986 CONFIG_CDP_POWER_CONSUMPTION
1988 A 16bit integer containing the power consumption of the
1989 device in .1 of milliwatts.
1991 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1993 A byte containing the id of the VLAN.
1995 - Status LED: CONFIG_LED_STATUS
1997 Several configurations allow to display the current
1998 status using a LED. For instance, the LED will blink
1999 fast while running U-Boot code, stop blinking as
2000 soon as a reply to a BOOTP request was received, and
2001 start blinking slow once the Linux kernel is running
2002 (supported by a status LED driver in the Linux
2003 kernel). Defining CONFIG_LED_STATUS enables this
2008 CONFIG_LED_STATUS_GPIO
2009 The status LED can be connected to a GPIO pin.
2010 In such cases, the gpio_led driver can be used as a
2011 status LED backend implementation. Define CONFIG_LED_STATUS_GPIO
2012 to include the gpio_led driver in the U-Boot binary.
2014 CONFIG_GPIO_LED_INVERTED_TABLE
2015 Some GPIO connected LEDs may have inverted polarity in which
2016 case the GPIO high value corresponds to LED off state and
2017 GPIO low value corresponds to LED on state.
2018 In such cases CONFIG_GPIO_LED_INVERTED_TABLE may be defined
2019 with a list of GPIO LEDs that have inverted polarity.
2021 - CAN Support: CONFIG_CAN_DRIVER
2023 Defining CONFIG_CAN_DRIVER enables CAN driver support
2024 on those systems that support this (optional)
2025 feature, like the TQM8xxL modules.
2027 - I2C Support: CONFIG_SYS_I2C
2029 This enable the NEW i2c subsystem, and will allow you to use
2030 i2c commands at the u-boot command line (as long as you set
2031 CONFIG_CMD_I2C in CONFIG_COMMANDS) and communicate with i2c
2032 based realtime clock chips or other i2c devices. See
2033 common/cmd_i2c.c for a description of the command line
2036 ported i2c driver to the new framework:
2037 - drivers/i2c/soft_i2c.c:
2038 - activate first bus with CONFIG_SYS_I2C_SOFT define
2039 CONFIG_SYS_I2C_SOFT_SPEED and CONFIG_SYS_I2C_SOFT_SLAVE
2040 for defining speed and slave address
2041 - activate second bus with I2C_SOFT_DECLARATIONS2 define
2042 CONFIG_SYS_I2C_SOFT_SPEED_2 and CONFIG_SYS_I2C_SOFT_SLAVE_2
2043 for defining speed and slave address
2044 - activate third bus with I2C_SOFT_DECLARATIONS3 define
2045 CONFIG_SYS_I2C_SOFT_SPEED_3 and CONFIG_SYS_I2C_SOFT_SLAVE_3
2046 for defining speed and slave address
2047 - activate fourth bus with I2C_SOFT_DECLARATIONS4 define
2048 CONFIG_SYS_I2C_SOFT_SPEED_4 and CONFIG_SYS_I2C_SOFT_SLAVE_4
2049 for defining speed and slave address
2051 - drivers/i2c/fsl_i2c.c:
2052 - activate i2c driver with CONFIG_SYS_I2C_FSL
2053 define CONFIG_SYS_FSL_I2C_OFFSET for setting the register
2054 offset CONFIG_SYS_FSL_I2C_SPEED for the i2c speed and
2055 CONFIG_SYS_FSL_I2C_SLAVE for the slave addr of the first
2057 - If your board supports a second fsl i2c bus, define
2058 CONFIG_SYS_FSL_I2C2_OFFSET for the register offset
2059 CONFIG_SYS_FSL_I2C2_SPEED for the speed and
2060 CONFIG_SYS_FSL_I2C2_SLAVE for the slave address of the
2063 - drivers/i2c/tegra_i2c.c:
2064 - activate this driver with CONFIG_SYS_I2C_TEGRA
2065 - This driver adds 4 i2c buses with a fix speed from
2066 100000 and the slave addr 0!
2068 - drivers/i2c/ppc4xx_i2c.c
2069 - activate this driver with CONFIG_SYS_I2C_PPC4XX
2070 - CONFIG_SYS_I2C_PPC4XX_CH0 activate hardware channel 0
2071 - CONFIG_SYS_I2C_PPC4XX_CH1 activate hardware channel 1
2073 - drivers/i2c/i2c_mxc.c
2074 - activate this driver with CONFIG_SYS_I2C_MXC
2075 - enable bus 1 with CONFIG_SYS_I2C_MXC_I2C1
2076 - enable bus 2 with CONFIG_SYS_I2C_MXC_I2C2
2077 - enable bus 3 with CONFIG_SYS_I2C_MXC_I2C3
2078 - enable bus 4 with CONFIG_SYS_I2C_MXC_I2C4
2079 - define speed for bus 1 with CONFIG_SYS_MXC_I2C1_SPEED
2080 - define slave for bus 1 with CONFIG_SYS_MXC_I2C1_SLAVE
2081 - define speed for bus 2 with CONFIG_SYS_MXC_I2C2_SPEED
2082 - define slave for bus 2 with CONFIG_SYS_MXC_I2C2_SLAVE
2083 - define speed for bus 3 with CONFIG_SYS_MXC_I2C3_SPEED
2084 - define slave for bus 3 with CONFIG_SYS_MXC_I2C3_SLAVE
2085 - define speed for bus 4 with CONFIG_SYS_MXC_I2C4_SPEED
2086 - define slave for bus 4 with CONFIG_SYS_MXC_I2C4_SLAVE
2087 If those defines are not set, default value is 100000
2088 for speed, and 0 for slave.
2090 - drivers/i2c/rcar_i2c.c:
2091 - activate this driver with CONFIG_SYS_I2C_RCAR
2092 - This driver adds 4 i2c buses
2094 - CONFIG_SYS_RCAR_I2C0_BASE for setting the register channel 0
2095 - CONFIG_SYS_RCAR_I2C0_SPEED for for the speed channel 0
2096 - CONFIG_SYS_RCAR_I2C1_BASE for setting the register channel 1
2097 - CONFIG_SYS_RCAR_I2C1_SPEED for for the speed channel 1
2098 - CONFIG_SYS_RCAR_I2C2_BASE for setting the register channel 2
2099 - CONFIG_SYS_RCAR_I2C2_SPEED for for the speed channel 2
2100 - CONFIG_SYS_RCAR_I2C3_BASE for setting the register channel 3
2101 - CONFIG_SYS_RCAR_I2C3_SPEED for for the speed channel 3
2102 - CONFIF_SYS_RCAR_I2C_NUM_CONTROLLERS for number of i2c buses
2104 - drivers/i2c/sh_i2c.c:
2105 - activate this driver with CONFIG_SYS_I2C_SH
2106 - This driver adds from 2 to 5 i2c buses
2108 - CONFIG_SYS_I2C_SH_BASE0 for setting the register channel 0
2109 - CONFIG_SYS_I2C_SH_SPEED0 for for the speed channel 0
2110 - CONFIG_SYS_I2C_SH_BASE1 for setting the register channel 1
2111 - CONFIG_SYS_I2C_SH_SPEED1 for for the speed channel 1
2112 - CONFIG_SYS_I2C_SH_BASE2 for setting the register channel 2
2113 - CONFIG_SYS_I2C_SH_SPEED2 for for the speed channel 2
2114 - CONFIG_SYS_I2C_SH_BASE3 for setting the register channel 3
2115 - CONFIG_SYS_I2C_SH_SPEED3 for for the speed channel 3
2116 - CONFIG_SYS_I2C_SH_BASE4 for setting the register channel 4
2117 - CONFIG_SYS_I2C_SH_SPEED4 for for the speed channel 4
2118 - CONFIG_SYS_I2C_SH_NUM_CONTROLLERS for number of i2c buses
2120 - drivers/i2c/omap24xx_i2c.c
2121 - activate this driver with CONFIG_SYS_I2C_OMAP24XX
2122 - CONFIG_SYS_OMAP24_I2C_SPEED speed channel 0
2123 - CONFIG_SYS_OMAP24_I2C_SLAVE slave addr channel 0
2124 - CONFIG_SYS_OMAP24_I2C_SPEED1 speed channel 1
2125 - CONFIG_SYS_OMAP24_I2C_SLAVE1 slave addr channel 1
2126 - CONFIG_SYS_OMAP24_I2C_SPEED2 speed channel 2
2127 - CONFIG_SYS_OMAP24_I2C_SLAVE2 slave addr channel 2
2128 - CONFIG_SYS_OMAP24_I2C_SPEED3 speed channel 3
2129 - CONFIG_SYS_OMAP24_I2C_SLAVE3 slave addr channel 3
2130 - CONFIG_SYS_OMAP24_I2C_SPEED4 speed channel 4
2131 - CONFIG_SYS_OMAP24_I2C_SLAVE4 slave addr channel 4
2133 - drivers/i2c/zynq_i2c.c
2134 - activate this driver with CONFIG_SYS_I2C_ZYNQ
2135 - set CONFIG_SYS_I2C_ZYNQ_SPEED for speed setting
2136 - set CONFIG_SYS_I2C_ZYNQ_SLAVE for slave addr
2138 - drivers/i2c/s3c24x0_i2c.c:
2139 - activate this driver with CONFIG_SYS_I2C_S3C24X0
2140 - This driver adds i2c buses (11 for Exynos5250, Exynos5420
2141 9 i2c buses for Exynos4 and 1 for S3C24X0 SoCs from Samsung)
2142 with a fix speed from 100000 and the slave addr 0!
2144 - drivers/i2c/ihs_i2c.c
2145 - activate this driver with CONFIG_SYS_I2C_IHS
2146 - CONFIG_SYS_I2C_IHS_CH0 activate hardware channel 0
2147 - CONFIG_SYS_I2C_IHS_SPEED_0 speed channel 0
2148 - CONFIG_SYS_I2C_IHS_SLAVE_0 slave addr channel 0
2149 - CONFIG_SYS_I2C_IHS_CH1 activate hardware channel 1
2150 - CONFIG_SYS_I2C_IHS_SPEED_1 speed channel 1
2151 - CONFIG_SYS_I2C_IHS_SLAVE_1 slave addr channel 1
2152 - CONFIG_SYS_I2C_IHS_CH2 activate hardware channel 2
2153 - CONFIG_SYS_I2C_IHS_SPEED_2 speed channel 2
2154 - CONFIG_SYS_I2C_IHS_SLAVE_2 slave addr channel 2
2155 - CONFIG_SYS_I2C_IHS_CH3 activate hardware channel 3
2156 - CONFIG_SYS_I2C_IHS_SPEED_3 speed channel 3
2157 - CONFIG_SYS_I2C_IHS_SLAVE_3 slave addr channel 3
2158 - activate dual channel with CONFIG_SYS_I2C_IHS_DUAL
2159 - CONFIG_SYS_I2C_IHS_SPEED_0_1 speed channel 0_1
2160 - CONFIG_SYS_I2C_IHS_SLAVE_0_1 slave addr channel 0_1
2161 - CONFIG_SYS_I2C_IHS_SPEED_1_1 speed channel 1_1
2162 - CONFIG_SYS_I2C_IHS_SLAVE_1_1 slave addr channel 1_1
2163 - CONFIG_SYS_I2C_IHS_SPEED_2_1 speed channel 2_1
2164 - CONFIG_SYS_I2C_IHS_SLAVE_2_1 slave addr channel 2_1
2165 - CONFIG_SYS_I2C_IHS_SPEED_3_1 speed channel 3_1
2166 - CONFIG_SYS_I2C_IHS_SLAVE_3_1 slave addr channel 3_1
2170 CONFIG_SYS_NUM_I2C_BUSES
2171 Hold the number of i2c buses you want to use.
2173 CONFIG_SYS_I2C_DIRECT_BUS
2174 define this, if you don't use i2c muxes on your hardware.
2175 if CONFIG_SYS_I2C_MAX_HOPS is not defined or == 0 you can
2178 CONFIG_SYS_I2C_MAX_HOPS
2179 define how many muxes are maximal consecutively connected
2180 on one i2c bus. If you not use i2c muxes, omit this
2183 CONFIG_SYS_I2C_BUSES
2184 hold a list of buses you want to use, only used if
2185 CONFIG_SYS_I2C_DIRECT_BUS is not defined, for example
2186 a board with CONFIG_SYS_I2C_MAX_HOPS = 1 and
2187 CONFIG_SYS_NUM_I2C_BUSES = 9:
2189 CONFIG_SYS_I2C_BUSES {{0, {I2C_NULL_HOP}}, \
2190 {0, {{I2C_MUX_PCA9547, 0x70, 1}}}, \
2191 {0, {{I2C_MUX_PCA9547, 0x70, 2}}}, \
2192 {0, {{I2C_MUX_PCA9547, 0x70, 3}}}, \
2193 {0, {{I2C_MUX_PCA9547, 0x70, 4}}}, \
2194 {0, {{I2C_MUX_PCA9547, 0x70, 5}}}, \
2195 {1, {I2C_NULL_HOP}}, \
2196 {1, {{I2C_MUX_PCA9544, 0x72, 1}}}, \
2197 {1, {{I2C_MUX_PCA9544, 0x72, 2}}}, \
2201 bus 0 on adapter 0 without a mux
2202 bus 1 on adapter 0 with a PCA9547 on address 0x70 port 1
2203 bus 2 on adapter 0 with a PCA9547 on address 0x70 port 2
2204 bus 3 on adapter 0 with a PCA9547 on address 0x70 port 3
2205 bus 4 on adapter 0 with a PCA9547 on address 0x70 port 4
2206 bus 5 on adapter 0 with a PCA9547 on address 0x70 port 5
2207 bus 6 on adapter 1 without a mux
2208 bus 7 on adapter 1 with a PCA9544 on address 0x72 port 1
2209 bus 8 on adapter 1 with a PCA9544 on address 0x72 port 2
2211 If you do not have i2c muxes on your board, omit this define.
2213 - Legacy I2C Support: CONFIG_HARD_I2C
2215 NOTE: It is intended to move drivers to CONFIG_SYS_I2C which
2216 provides the following compelling advantages:
2218 - more than one i2c adapter is usable
2219 - approved multibus support
2220 - better i2c mux support
2222 ** Please consider updating your I2C driver now. **
2224 These enable legacy I2C serial bus commands. Defining
2225 CONFIG_HARD_I2C will include the appropriate I2C driver
2226 for the selected CPU.
2228 This will allow you to use i2c commands at the u-boot
2229 command line (as long as you set CONFIG_CMD_I2C in
2230 CONFIG_COMMANDS) and communicate with i2c based realtime
2231 clock chips. See common/cmd_i2c.c for a description of the
2232 command line interface.
2234 CONFIG_HARD_I2C selects a hardware I2C controller.
2236 There are several other quantities that must also be
2237 defined when you define CONFIG_HARD_I2C.
2239 In both cases you will need to define CONFIG_SYS_I2C_SPEED
2240 to be the frequency (in Hz) at which you wish your i2c bus
2241 to run and CONFIG_SYS_I2C_SLAVE to be the address of this node (ie
2242 the CPU's i2c node address).
2244 Now, the u-boot i2c code for the mpc8xx
2245 (arch/powerpc/cpu/mpc8xx/i2c.c) sets the CPU up as a master node
2246 and so its address should therefore be cleared to 0 (See,
2247 eg, MPC823e User's Manual p.16-473). So, set
2248 CONFIG_SYS_I2C_SLAVE to 0.
2250 CONFIG_SYS_I2C_INIT_MPC5XXX
2252 When a board is reset during an i2c bus transfer
2253 chips might think that the current transfer is still
2254 in progress. Reset the slave devices by sending start
2255 commands until the slave device responds.
2257 That's all that's required for CONFIG_HARD_I2C.
2259 If you use the software i2c interface (CONFIG_SYS_I2C_SOFT)
2260 then the following macros need to be defined (examples are
2261 from include/configs/lwmon.h):
2265 (Optional). Any commands necessary to enable the I2C
2266 controller or configure ports.
2268 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
2272 (Only for MPC8260 CPU). The I/O port to use (the code
2273 assumes both bits are on the same port). Valid values
2274 are 0..3 for ports A..D.
2278 The code necessary to make the I2C data line active
2279 (driven). If the data line is open collector, this
2282 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
2286 The code necessary to make the I2C data line tri-stated
2287 (inactive). If the data line is open collector, this
2290 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
2294 Code that returns true if the I2C data line is high,
2297 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
2301 If <bit> is true, sets the I2C data line high. If it
2302 is false, it clears it (low).
2304 eg: #define I2C_SDA(bit) \
2305 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
2306 else immr->im_cpm.cp_pbdat &= ~PB_SDA
2310 If <bit> is true, sets the I2C clock line high. If it
2311 is false, it clears it (low).
2313 eg: #define I2C_SCL(bit) \
2314 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
2315 else immr->im_cpm.cp_pbdat &= ~PB_SCL
2319 This delay is invoked four times per clock cycle so this
2320 controls the rate of data transfer. The data rate thus
2321 is 1 / (I2C_DELAY * 4). Often defined to be something
2324 #define I2C_DELAY udelay(2)
2326 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA
2328 If your arch supports the generic GPIO framework (asm/gpio.h),
2329 then you may alternatively define the two GPIOs that are to be
2330 used as SCL / SDA. Any of the previous I2C_xxx macros will
2331 have GPIO-based defaults assigned to them as appropriate.
2333 You should define these to the GPIO value as given directly to
2334 the generic GPIO functions.
2336 CONFIG_SYS_I2C_INIT_BOARD
2338 When a board is reset during an i2c bus transfer
2339 chips might think that the current transfer is still
2340 in progress. On some boards it is possible to access
2341 the i2c SCLK line directly, either by using the
2342 processor pin as a GPIO or by having a second pin
2343 connected to the bus. If this option is defined a
2344 custom i2c_init_board() routine in boards/xxx/board.c
2345 is run early in the boot sequence.
2347 CONFIG_SYS_I2C_BOARD_LATE_INIT
2349 An alternative to CONFIG_SYS_I2C_INIT_BOARD. If this option is
2350 defined a custom i2c_board_late_init() routine in
2351 boards/xxx/board.c is run AFTER the operations in i2c_init()
2352 is completed. This callpoint can be used to unreset i2c bus
2353 using CPU i2c controller register accesses for CPUs whose i2c
2354 controller provide such a method. It is called at the end of
2355 i2c_init() to allow i2c_init operations to setup the i2c bus
2356 controller on the CPU (e.g. setting bus speed & slave address).
2358 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
2360 This option enables configuration of bi_iic_fast[] flags
2361 in u-boot bd_info structure based on u-boot environment
2362 variable "i2cfast". (see also i2cfast)
2364 CONFIG_I2C_MULTI_BUS
2366 This option allows the use of multiple I2C buses, each of which
2367 must have a controller. At any point in time, only one bus is
2368 active. To switch to a different bus, use the 'i2c dev' command.
2369 Note that bus numbering is zero-based.
2371 CONFIG_SYS_I2C_NOPROBES
2373 This option specifies a list of I2C devices that will be skipped
2374 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS
2375 is set, specify a list of bus-device pairs. Otherwise, specify
2376 a 1D array of device addresses
2379 #undef CONFIG_I2C_MULTI_BUS
2380 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
2382 will skip addresses 0x50 and 0x68 on a board with one I2C bus
2384 #define CONFIG_I2C_MULTI_BUS
2385 #define CONFIG_SYS_I2C_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
2387 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
2389 CONFIG_SYS_SPD_BUS_NUM
2391 If defined, then this indicates the I2C bus number for DDR SPD.
2392 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
2394 CONFIG_SYS_RTC_BUS_NUM
2396 If defined, then this indicates the I2C bus number for the RTC.
2397 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
2399 CONFIG_SYS_DTT_BUS_NUM
2401 If defined, then this indicates the I2C bus number for the DTT.
2402 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
2404 CONFIG_SYS_I2C_DTT_ADDR:
2406 If defined, specifies the I2C address of the DTT device.
2407 If not defined, then U-Boot uses predefined value for
2408 specified DTT device.
2410 CONFIG_SOFT_I2C_READ_REPEATED_START
2412 defining this will force the i2c_read() function in
2413 the soft_i2c driver to perform an I2C repeated start
2414 between writing the address pointer and reading the
2415 data. If this define is omitted the default behaviour
2416 of doing a stop-start sequence will be used. Most I2C
2417 devices can use either method, but some require one or
2420 - SPI Support: CONFIG_SPI
2422 Enables SPI driver (so far only tested with
2423 SPI EEPROM, also an instance works with Crystal A/D and
2424 D/As on the SACSng board)
2428 Enables the driver for SPI controller on SuperH. Currently
2429 only SH7757 is supported.
2433 Enables a software (bit-bang) SPI driver rather than
2434 using hardware support. This is a general purpose
2435 driver that only requires three general I/O port pins
2436 (two outputs, one input) to function. If this is
2437 defined, the board configuration must define several
2438 SPI configuration items (port pins to use, etc). For
2439 an example, see include/configs/sacsng.h.
2443 Enables a hardware SPI driver for general-purpose reads
2444 and writes. As with CONFIG_SOFT_SPI, the board configuration
2445 must define a list of chip-select function pointers.
2446 Currently supported on some MPC8xxx processors. For an
2447 example, see include/configs/mpc8349emds.h.
2451 Enables the driver for the SPI controllers on i.MX and MXC
2452 SoCs. Currently i.MX31/35/51 are supported.
2454 CONFIG_SYS_SPI_MXC_WAIT
2455 Timeout for waiting until spi transfer completed.
2456 default: (CONFIG_SYS_HZ/100) /* 10 ms */
2458 - FPGA Support: CONFIG_FPGA
2460 Enables FPGA subsystem.
2462 CONFIG_FPGA_<vendor>
2464 Enables support for specific chip vendors.
2467 CONFIG_FPGA_<family>
2469 Enables support for FPGA family.
2470 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
2474 Specify the number of FPGA devices to support.
2476 CONFIG_CMD_FPGA_LOADMK
2478 Enable support for fpga loadmk command
2480 CONFIG_CMD_FPGA_LOADP
2482 Enable support for fpga loadp command - load partial bitstream
2484 CONFIG_CMD_FPGA_LOADBP
2486 Enable support for fpga loadbp command - load partial bitstream
2489 CONFIG_SYS_FPGA_PROG_FEEDBACK
2491 Enable printing of hash marks during FPGA configuration.
2493 CONFIG_SYS_FPGA_CHECK_BUSY
2495 Enable checks on FPGA configuration interface busy
2496 status by the configuration function. This option
2497 will require a board or device specific function to
2502 If defined, a function that provides delays in the FPGA
2503 configuration driver.
2505 CONFIG_SYS_FPGA_CHECK_CTRLC
2506 Allow Control-C to interrupt FPGA configuration
2508 CONFIG_SYS_FPGA_CHECK_ERROR
2510 Check for configuration errors during FPGA bitfile
2511 loading. For example, abort during Virtex II
2512 configuration if the INIT_B line goes low (which
2513 indicated a CRC error).
2515 CONFIG_SYS_FPGA_WAIT_INIT
2517 Maximum time to wait for the INIT_B line to de-assert
2518 after PROB_B has been de-asserted during a Virtex II
2519 FPGA configuration sequence. The default time is 500
2522 CONFIG_SYS_FPGA_WAIT_BUSY
2524 Maximum time to wait for BUSY to de-assert during
2525 Virtex II FPGA configuration. The default is 5 ms.
2527 CONFIG_SYS_FPGA_WAIT_CONFIG
2529 Time to wait after FPGA configuration. The default is
2532 - Configuration Management:
2535 Some SoCs need special image types (e.g. U-Boot binary
2536 with a special header) as build targets. By defining
2537 CONFIG_BUILD_TARGET in the SoC / board header, this
2538 special image will be automatically built upon calling
2543 If defined, this string will be added to the U-Boot
2544 version information (U_BOOT_VERSION)
2546 - Vendor Parameter Protection:
2548 U-Boot considers the values of the environment
2549 variables "serial#" (Board Serial Number) and
2550 "ethaddr" (Ethernet Address) to be parameters that
2551 are set once by the board vendor / manufacturer, and
2552 protects these variables from casual modification by
2553 the user. Once set, these variables are read-only,
2554 and write or delete attempts are rejected. You can
2555 change this behaviour:
2557 If CONFIG_ENV_OVERWRITE is #defined in your config
2558 file, the write protection for vendor parameters is
2559 completely disabled. Anybody can change or delete
2562 Alternatively, if you define _both_ an ethaddr in the
2563 default env _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
2564 Ethernet address is installed in the environment,
2565 which can be changed exactly ONCE by the user. [The
2566 serial# is unaffected by this, i. e. it remains
2569 The same can be accomplished in a more flexible way
2570 for any variable by configuring the type of access
2571 to allow for those variables in the ".flags" variable
2572 or define CONFIG_ENV_FLAGS_LIST_STATIC.
2577 Define this variable to enable the reservation of
2578 "protected RAM", i. e. RAM which is not overwritten
2579 by U-Boot. Define CONFIG_PRAM to hold the number of
2580 kB you want to reserve for pRAM. You can overwrite
2581 this default value by defining an environment
2582 variable "pram" to the number of kB you want to
2583 reserve. Note that the board info structure will
2584 still show the full amount of RAM. If pRAM is
2585 reserved, a new environment variable "mem" will
2586 automatically be defined to hold the amount of
2587 remaining RAM in a form that can be passed as boot
2588 argument to Linux, for instance like that:
2590 setenv bootargs ... mem=\${mem}
2593 This way you can tell Linux not to use this memory,
2594 either, which results in a memory region that will
2595 not be affected by reboots.
2597 *WARNING* If your board configuration uses automatic
2598 detection of the RAM size, you must make sure that
2599 this memory test is non-destructive. So far, the
2600 following board configurations are known to be
2603 IVMS8, IVML24, SPD8xx, TQM8xxL,
2604 HERMES, IP860, RPXlite, LWMON,
2607 - Access to physical memory region (> 4GB)
2608 Some basic support is provided for operations on memory not
2609 normally accessible to U-Boot - e.g. some architectures
2610 support access to more than 4GB of memory on 32-bit
2611 machines using physical address extension or similar.
2612 Define CONFIG_PHYSMEM to access this basic support, which
2613 currently only supports clearing the memory.
2618 Define this variable to stop the system in case of a
2619 fatal error, so that you have to reset it manually.
2620 This is probably NOT a good idea for an embedded
2621 system where you want the system to reboot
2622 automatically as fast as possible, but it may be
2623 useful during development since you can try to debug
2624 the conditions that lead to the situation.
2626 CONFIG_NET_RETRY_COUNT
2628 This variable defines the number of retries for
2629 network operations like ARP, RARP, TFTP, or BOOTP
2630 before giving up the operation. If not defined, a
2631 default value of 5 is used.
2635 Timeout waiting for an ARP reply in milliseconds.
2639 Timeout in milliseconds used in NFS protocol.
2640 If you encounter "ERROR: Cannot umount" in nfs command,
2641 try longer timeout such as
2642 #define CONFIG_NFS_TIMEOUT 10000UL
2644 - Command Interpreter:
2645 CONFIG_AUTO_COMPLETE
2647 Enable auto completion of commands using TAB.
2649 CONFIG_SYS_PROMPT_HUSH_PS2
2651 This defines the secondary prompt string, which is
2652 printed when the command interpreter needs more input
2653 to complete a command. Usually "> ".
2657 In the current implementation, the local variables
2658 space and global environment variables space are
2659 separated. Local variables are those you define by
2660 simply typing `name=value'. To access a local
2661 variable later on, you have write `$name' or
2662 `${name}'; to execute the contents of a variable
2663 directly type `$name' at the command prompt.
2665 Global environment variables are those you use
2666 setenv/printenv to work with. To run a command stored
2667 in such a variable, you need to use the run command,
2668 and you must not use the '$' sign to access them.
2670 To store commands and special characters in a
2671 variable, please use double quotation marks
2672 surrounding the whole text of the variable, instead
2673 of the backslashes before semicolons and special
2676 - Command Line Editing and History:
2677 CONFIG_CMDLINE_EDITING
2679 Enable editing and History functions for interactive
2680 command line input operations
2682 - Command Line PS1/PS2 support:
2683 CONFIG_CMDLINE_PS_SUPPORT
2685 Enable support for changing the command prompt string
2686 at run-time. Only static string is supported so far.
2687 The string is obtained from environment variables PS1
2690 - Default Environment:
2691 CONFIG_EXTRA_ENV_SETTINGS
2693 Define this to contain any number of null terminated
2694 strings (variable = value pairs) that will be part of
2695 the default environment compiled into the boot image.
2697 For example, place something like this in your
2698 board's config file:
2700 #define CONFIG_EXTRA_ENV_SETTINGS \
2704 Warning: This method is based on knowledge about the
2705 internal format how the environment is stored by the
2706 U-Boot code. This is NOT an official, exported
2707 interface! Although it is unlikely that this format
2708 will change soon, there is no guarantee either.
2709 You better know what you are doing here.
2711 Note: overly (ab)use of the default environment is
2712 discouraged. Make sure to check other ways to preset
2713 the environment like the "source" command or the
2716 CONFIG_ENV_VARS_UBOOT_CONFIG
2718 Define this in order to add variables describing the
2719 U-Boot build configuration to the default environment.
2720 These will be named arch, cpu, board, vendor, and soc.
2722 Enabling this option will cause the following to be defined:
2730 CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG
2732 Define this in order to add variables describing certain
2733 run-time determined information about the hardware to the
2734 environment. These will be named board_name, board_rev.
2736 CONFIG_DELAY_ENVIRONMENT
2738 Normally the environment is loaded when the board is
2739 initialised so that it is available to U-Boot. This inhibits
2740 that so that the environment is not available until
2741 explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL
2742 this is instead controlled by the value of
2743 /config/load-environment.
2745 - DataFlash Support:
2746 CONFIG_HAS_DATAFLASH
2748 Defining this option enables DataFlash features and
2749 allows to read/write in Dataflash via the standard
2752 - Serial Flash support
2755 Defining this option enables SPI flash commands
2756 'sf probe/read/write/erase/update'.
2758 Usage requires an initial 'probe' to define the serial
2759 flash parameters, followed by read/write/erase/update
2762 The following defaults may be provided by the platform
2763 to handle the common case when only a single serial
2764 flash is present on the system.
2766 CONFIG_SF_DEFAULT_BUS Bus identifier
2767 CONFIG_SF_DEFAULT_CS Chip-select
2768 CONFIG_SF_DEFAULT_MODE (see include/spi.h)
2769 CONFIG_SF_DEFAULT_SPEED in Hz
2773 Define this option to include a destructive SPI flash
2776 CONFIG_SF_DUAL_FLASH Dual flash memories
2778 Define this option to use dual flash support where two flash
2779 memories can be connected with a given cs line.
2780 Currently Xilinx Zynq qspi supports these type of connections.
2782 - SystemACE Support:
2785 Adding this option adds support for Xilinx SystemACE
2786 chips attached via some sort of local bus. The address
2787 of the chip must also be defined in the
2788 CONFIG_SYS_SYSTEMACE_BASE macro. For example:
2790 #define CONFIG_SYSTEMACE
2791 #define CONFIG_SYS_SYSTEMACE_BASE 0xf0000000
2793 When SystemACE support is added, the "ace" device type
2794 becomes available to the fat commands, i.e. fatls.
2796 - TFTP Fixed UDP Port:
2799 If this is defined, the environment variable tftpsrcp
2800 is used to supply the TFTP UDP source port value.
2801 If tftpsrcp isn't defined, the normal pseudo-random port
2802 number generator is used.
2804 Also, the environment variable tftpdstp is used to supply
2805 the TFTP UDP destination port value. If tftpdstp isn't
2806 defined, the normal port 69 is used.
2808 The purpose for tftpsrcp is to allow a TFTP server to
2809 blindly start the TFTP transfer using the pre-configured
2810 target IP address and UDP port. This has the effect of
2811 "punching through" the (Windows XP) firewall, allowing
2812 the remainder of the TFTP transfer to proceed normally.
2813 A better solution is to properly configure the firewall,
2814 but sometimes that is not allowed.
2819 This enables a generic 'hash' command which can produce
2820 hashes / digests from a few algorithms (e.g. SHA1, SHA256).
2824 Enable the hash verify command (hash -v). This adds to code
2827 CONFIG_SHA1 - This option enables support of hashing using SHA1
2828 algorithm. The hash is calculated in software.
2829 CONFIG_SHA256 - This option enables support of hashing using
2830 SHA256 algorithm. The hash is calculated in software.
2831 CONFIG_SHA_HW_ACCEL - This option enables hardware acceleration
2832 for SHA1/SHA256 hashing.
2833 This affects the 'hash' command and also the
2834 hash_lookup_algo() function.
2835 CONFIG_SHA_PROG_HW_ACCEL - This option enables
2836 hardware-acceleration for SHA1/SHA256 progressive hashing.
2837 Data can be streamed in a block at a time and the hashing
2838 is performed in hardware.
2840 Note: There is also a sha1sum command, which should perhaps
2841 be deprecated in favour of 'hash sha1'.
2843 - Freescale i.MX specific commands:
2844 CONFIG_CMD_HDMIDETECT
2845 This enables 'hdmidet' command which returns true if an
2846 HDMI monitor is detected. This command is i.MX 6 specific.
2848 - bootcount support:
2849 CONFIG_BOOTCOUNT_LIMIT
2851 This enables the bootcounter support, see:
2852 http://www.denx.de/wiki/DULG/UBootBootCountLimit
2855 enable special bootcounter support on at91sam9xe based boards.
2857 enable special bootcounter support on da850 based boards.
2858 CONFIG_BOOTCOUNT_RAM
2859 enable support for the bootcounter in RAM
2860 CONFIG_BOOTCOUNT_I2C
2861 enable support for the bootcounter on an i2c (like RTC) device.
2862 CONFIG_SYS_I2C_RTC_ADDR = i2c chip address
2863 CONFIG_SYS_BOOTCOUNT_ADDR = i2c addr which is used for
2865 CONFIG_BOOTCOUNT_ALEN = address len
2867 - Show boot progress:
2868 CONFIG_SHOW_BOOT_PROGRESS
2870 Defining this option allows to add some board-
2871 specific code (calling a user-provided function
2872 "show_boot_progress(int)") that enables you to show
2873 the system's boot progress on some display (for
2874 example, some LED's) on your board. At the moment,
2875 the following checkpoints are implemented:
2878 Legacy uImage format:
2881 1 common/cmd_bootm.c before attempting to boot an image
2882 -1 common/cmd_bootm.c Image header has bad magic number
2883 2 common/cmd_bootm.c Image header has correct magic number
2884 -2 common/cmd_bootm.c Image header has bad checksum
2885 3 common/cmd_bootm.c Image header has correct checksum
2886 -3 common/cmd_bootm.c Image data has bad checksum
2887 4 common/cmd_bootm.c Image data has correct checksum
2888 -4 common/cmd_bootm.c Image is for unsupported architecture
2889 5 common/cmd_bootm.c Architecture check OK
2890 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
2891 6 common/cmd_bootm.c Image Type check OK
2892 -6 common/cmd_bootm.c gunzip uncompression error
2893 -7 common/cmd_bootm.c Unimplemented compression type
2894 7 common/cmd_bootm.c Uncompression OK
2895 8 common/cmd_bootm.c No uncompress/copy overwrite error
2896 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
2898 9 common/image.c Start initial ramdisk verification
2899 -10 common/image.c Ramdisk header has bad magic number
2900 -11 common/image.c Ramdisk header has bad checksum
2901 10 common/image.c Ramdisk header is OK
2902 -12 common/image.c Ramdisk data has bad checksum
2903 11 common/image.c Ramdisk data has correct checksum
2904 12 common/image.c Ramdisk verification complete, start loading
2905 -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
2906 13 common/image.c Start multifile image verification
2907 14 common/image.c No initial ramdisk, no multifile, continue.
2909 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
2911 -30 arch/powerpc/lib/board.c Fatal error, hang the system
2912 -31 post/post.c POST test failed, detected by post_output_backlog()
2913 -32 post/post.c POST test failed, detected by post_run_single()
2915 34 common/cmd_doc.c before loading a Image from a DOC device
2916 -35 common/cmd_doc.c Bad usage of "doc" command
2917 35 common/cmd_doc.c correct usage of "doc" command
2918 -36 common/cmd_doc.c No boot device
2919 36 common/cmd_doc.c correct boot device
2920 -37 common/cmd_doc.c Unknown Chip ID on boot device
2921 37 common/cmd_doc.c correct chip ID found, device available
2922 -38 common/cmd_doc.c Read Error on boot device
2923 38 common/cmd_doc.c reading Image header from DOC device OK
2924 -39 common/cmd_doc.c Image header has bad magic number
2925 39 common/cmd_doc.c Image header has correct magic number
2926 -40 common/cmd_doc.c Error reading Image from DOC device
2927 40 common/cmd_doc.c Image header has correct magic number
2928 41 common/cmd_ide.c before loading a Image from a IDE device
2929 -42 common/cmd_ide.c Bad usage of "ide" command
2930 42 common/cmd_ide.c correct usage of "ide" command
2931 -43 common/cmd_ide.c No boot device
2932 43 common/cmd_ide.c boot device found
2933 -44 common/cmd_ide.c Device not available
2934 44 common/cmd_ide.c Device available
2935 -45 common/cmd_ide.c wrong partition selected
2936 45 common/cmd_ide.c partition selected
2937 -46 common/cmd_ide.c Unknown partition table
2938 46 common/cmd_ide.c valid partition table found
2939 -47 common/cmd_ide.c Invalid partition type
2940 47 common/cmd_ide.c correct partition type
2941 -48 common/cmd_ide.c Error reading Image Header on boot device
2942 48 common/cmd_ide.c reading Image Header from IDE device OK
2943 -49 common/cmd_ide.c Image header has bad magic number
2944 49 common/cmd_ide.c Image header has correct magic number
2945 -50 common/cmd_ide.c Image header has bad checksum
2946 50 common/cmd_ide.c Image header has correct checksum
2947 -51 common/cmd_ide.c Error reading Image from IDE device
2948 51 common/cmd_ide.c reading Image from IDE device OK
2949 52 common/cmd_nand.c before loading a Image from a NAND device
2950 -53 common/cmd_nand.c Bad usage of "nand" command
2951 53 common/cmd_nand.c correct usage of "nand" command
2952 -54 common/cmd_nand.c No boot device
2953 54 common/cmd_nand.c boot device found
2954 -55 common/cmd_nand.c Unknown Chip ID on boot device
2955 55 common/cmd_nand.c correct chip ID found, device available
2956 -56 common/cmd_nand.c Error reading Image Header on boot device
2957 56 common/cmd_nand.c reading Image Header from NAND device OK
2958 -57 common/cmd_nand.c Image header has bad magic number
2959 57 common/cmd_nand.c Image header has correct magic number
2960 -58 common/cmd_nand.c Error reading Image from NAND device
2961 58 common/cmd_nand.c reading Image from NAND device OK
2963 -60 common/env_common.c Environment has a bad CRC, using default
2965 64 net/eth.c starting with Ethernet configuration.
2966 -64 net/eth.c no Ethernet found.
2967 65 net/eth.c Ethernet found.
2969 -80 common/cmd_net.c usage wrong
2970 80 common/cmd_net.c before calling net_loop()
2971 -81 common/cmd_net.c some error in net_loop() occurred
2972 81 common/cmd_net.c net_loop() back without error
2973 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
2974 82 common/cmd_net.c trying automatic boot
2975 83 common/cmd_net.c running "source" command
2976 -83 common/cmd_net.c some error in automatic boot or "source" command
2977 84 common/cmd_net.c end without errors
2982 100 common/cmd_bootm.c Kernel FIT Image has correct format
2983 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
2984 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
2985 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
2986 102 common/cmd_bootm.c Kernel unit name specified
2987 -103 common/cmd_bootm.c Can't get kernel subimage node offset
2988 103 common/cmd_bootm.c Found configuration node
2989 104 common/cmd_bootm.c Got kernel subimage node offset
2990 -104 common/cmd_bootm.c Kernel subimage hash verification failed
2991 105 common/cmd_bootm.c Kernel subimage hash verification OK
2992 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
2993 106 common/cmd_bootm.c Architecture check OK
2994 -106 common/cmd_bootm.c Kernel subimage has wrong type
2995 107 common/cmd_bootm.c Kernel subimage type OK
2996 -107 common/cmd_bootm.c Can't get kernel subimage data/size
2997 108 common/cmd_bootm.c Got kernel subimage data/size
2998 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
2999 -109 common/cmd_bootm.c Can't get kernel subimage type
3000 -110 common/cmd_bootm.c Can't get kernel subimage comp
3001 -111 common/cmd_bootm.c Can't get kernel subimage os
3002 -112 common/cmd_bootm.c Can't get kernel subimage load address
3003 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
3005 120 common/image.c Start initial ramdisk verification
3006 -120 common/image.c Ramdisk FIT image has incorrect format
3007 121 common/image.c Ramdisk FIT image has correct format
3008 122 common/image.c No ramdisk subimage unit name, using configuration
3009 -122 common/image.c Can't get configuration for ramdisk subimage
3010 123 common/image.c Ramdisk unit name specified
3011 -124 common/image.c Can't get ramdisk subimage node offset
3012 125 common/image.c Got ramdisk subimage node offset
3013 -125 common/image.c Ramdisk subimage hash verification failed
3014 126 common/image.c Ramdisk subimage hash verification OK
3015 -126 common/image.c Ramdisk subimage for unsupported architecture
3016 127 common/image.c Architecture check OK
3017 -127 common/image.c Can't get ramdisk subimage data/size
3018 128 common/image.c Got ramdisk subimage data/size
3019 129 common/image.c Can't get ramdisk load address
3020 -129 common/image.c Got ramdisk load address
3022 -130 common/cmd_doc.c Incorrect FIT image format
3023 131 common/cmd_doc.c FIT image format OK
3025 -140 common/cmd_ide.c Incorrect FIT image format
3026 141 common/cmd_ide.c FIT image format OK
3028 -150 common/cmd_nand.c Incorrect FIT image format
3029 151 common/cmd_nand.c FIT image format OK
3031 - legacy image format:
3032 CONFIG_IMAGE_FORMAT_LEGACY
3033 enables the legacy image format support in U-Boot.
3036 enabled if CONFIG_FIT_SIGNATURE is not defined.
3038 CONFIG_DISABLE_IMAGE_LEGACY
3039 disable the legacy image format
3041 This define is introduced, as the legacy image format is
3042 enabled per default for backward compatibility.
3044 - FIT image support:
3045 CONFIG_FIT_DISABLE_SHA256
3046 Supporting SHA256 hashes has quite an impact on binary size.
3047 For constrained systems sha256 hash support can be disabled
3050 TODO(sjg@chromium.org): Adjust this option to be positive,
3051 and move it to Kconfig
3053 - Standalone program support:
3054 CONFIG_STANDALONE_LOAD_ADDR
3056 This option defines a board specific value for the
3057 address where standalone program gets loaded, thus
3058 overwriting the architecture dependent default
3061 - Frame Buffer Address:
3064 Define CONFIG_FB_ADDR if you want to use specific
3065 address for frame buffer. This is typically the case
3066 when using a graphics controller has separate video
3067 memory. U-Boot will then place the frame buffer at
3068 the given address instead of dynamically reserving it
3069 in system RAM by calling lcd_setmem(), which grabs
3070 the memory for the frame buffer depending on the
3071 configured panel size.
3073 Please see board_init_f function.
3075 - Automatic software updates via TFTP server
3077 CONFIG_UPDATE_TFTP_CNT_MAX
3078 CONFIG_UPDATE_TFTP_MSEC_MAX
3080 These options enable and control the auto-update feature;
3081 for a more detailed description refer to doc/README.update.
3083 - MTD Support (mtdparts command, UBI support)
3086 Adds the MTD device infrastructure from the Linux kernel.
3087 Needed for mtdparts command support.
3089 CONFIG_MTD_PARTITIONS
3091 Adds the MTD partitioning infrastructure from the Linux
3092 kernel. Needed for UBI support.
3097 Adds commands for interacting with MTD partitions formatted
3098 with the UBI flash translation layer
3100 Requires also defining CONFIG_RBTREE
3102 CONFIG_UBI_SILENCE_MSG
3104 Make the verbose messages from UBI stop printing. This leaves
3105 warnings and errors enabled.
3108 CONFIG_MTD_UBI_WL_THRESHOLD
3109 This parameter defines the maximum difference between the highest
3110 erase counter value and the lowest erase counter value of eraseblocks
3111 of UBI devices. When this threshold is exceeded, UBI starts performing
3112 wear leveling by means of moving data from eraseblock with low erase
3113 counter to eraseblocks with high erase counter.
3115 The default value should be OK for SLC NAND flashes, NOR flashes and
3116 other flashes which have eraseblock life-cycle 100000 or more.
3117 However, in case of MLC NAND flashes which typically have eraseblock
3118 life-cycle less than 10000, the threshold should be lessened (e.g.,
3119 to 128 or 256, although it does not have to be power of 2).
3123 CONFIG_MTD_UBI_BEB_LIMIT
3124 This option specifies the maximum bad physical eraseblocks UBI
3125 expects on the MTD device (per 1024 eraseblocks). If the
3126 underlying flash does not admit of bad eraseblocks (e.g. NOR
3127 flash), this value is ignored.
3129 NAND datasheets often specify the minimum and maximum NVM
3130 (Number of Valid Blocks) for the flashes' endurance lifetime.
3131 The maximum expected bad eraseblocks per 1024 eraseblocks
3132 then can be calculated as "1024 * (1 - MinNVB / MaxNVB)",
3133 which gives 20 for most NANDs (MaxNVB is basically the total
3134 count of eraseblocks on the chip).
3136 To put it differently, if this value is 20, UBI will try to
3137 reserve about 1.9% of physical eraseblocks for bad blocks
3138 handling. And that will be 1.9% of eraseblocks on the entire
3139 NAND chip, not just the MTD partition UBI attaches. This means
3140 that if you have, say, a NAND flash chip admits maximum 40 bad
3141 eraseblocks, and it is split on two MTD partitions of the same
3142 size, UBI will reserve 40 eraseblocks when attaching a
3147 CONFIG_MTD_UBI_FASTMAP
3148 Fastmap is a mechanism which allows attaching an UBI device
3149 in nearly constant time. Instead of scanning the whole MTD device it
3150 only has to locate a checkpoint (called fastmap) on the device.
3151 The on-flash fastmap contains all information needed to attach
3152 the device. Using fastmap makes only sense on large devices where
3153 attaching by scanning takes long. UBI will not automatically install
3154 a fastmap on old images, but you can set the UBI parameter
3155 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT to 1 if you want so. Please note
3156 that fastmap-enabled images are still usable with UBI implementations
3157 without fastmap support. On typical flash devices the whole fastmap
3158 fits into one PEB. UBI will reserve PEBs to hold two fastmaps.
3160 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT
3161 Set this parameter to enable fastmap automatically on images
3165 CONFIG_MTD_UBI_FM_DEBUG
3166 Enable UBI fastmap debug
3172 Adds commands for interacting with UBI volumes formatted as
3173 UBIFS. UBIFS is read-only in u-boot.
3175 Requires UBI support as well as CONFIG_LZO
3177 CONFIG_UBIFS_SILENCE_MSG
3179 Make the verbose messages from UBIFS stop printing. This leaves
3180 warnings and errors enabled.
3184 Enable building of SPL globally.
3187 LDSCRIPT for linking the SPL binary.
3189 CONFIG_SPL_MAX_FOOTPRINT
3190 Maximum size in memory allocated to the SPL, BSS included.
3191 When defined, the linker checks that the actual memory
3192 used by SPL from _start to __bss_end does not exceed it.
3193 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3194 must not be both defined at the same time.
3197 Maximum size of the SPL image (text, data, rodata, and
3198 linker lists sections), BSS excluded.
3199 When defined, the linker checks that the actual size does
3202 CONFIG_SPL_TEXT_BASE
3203 TEXT_BASE for linking the SPL binary.
3205 CONFIG_SPL_RELOC_TEXT_BASE
3206 Address to relocate to. If unspecified, this is equal to
3207 CONFIG_SPL_TEXT_BASE (i.e. no relocation is done).
3209 CONFIG_SPL_BSS_START_ADDR
3210 Link address for the BSS within the SPL binary.
3212 CONFIG_SPL_BSS_MAX_SIZE
3213 Maximum size in memory allocated to the SPL BSS.
3214 When defined, the linker checks that the actual memory used
3215 by SPL from __bss_start to __bss_end does not exceed it.
3216 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE
3217 must not be both defined at the same time.
3220 Adress of the start of the stack SPL will use
3222 CONFIG_SPL_PANIC_ON_RAW_IMAGE
3223 When defined, SPL will panic() if the image it has
3224 loaded does not have a signature.
3225 Defining this is useful when code which loads images
3226 in SPL cannot guarantee that absolutely all read errors
3228 An example is the LPC32XX MLC NAND driver, which will
3229 consider that a completely unreadable NAND block is bad,
3230 and thus should be skipped silently.
3232 CONFIG_SPL_RELOC_STACK
3233 Adress of the start of the stack SPL will use after
3234 relocation. If unspecified, this is equal to
3237 CONFIG_SYS_SPL_MALLOC_START
3238 Starting address of the malloc pool used in SPL.
3239 When this option is set the full malloc is used in SPL and
3240 it is set up by spl_init() and before that, the simple malloc()
3241 can be used if CONFIG_SYS_MALLOC_F is defined.
3243 CONFIG_SYS_SPL_MALLOC_SIZE
3244 The size of the malloc pool used in SPL.
3246 CONFIG_SPL_FRAMEWORK
3247 Enable the SPL framework under common/. This framework
3248 supports MMC, NAND and YMODEM loading of U-Boot and NAND
3249 NAND loading of the Linux Kernel.
3252 Enable booting directly to an OS from SPL.
3253 See also: doc/README.falcon
3255 CONFIG_SPL_DISPLAY_PRINT
3256 For ARM, enable an optional function to print more information
3257 about the running system.
3259 CONFIG_SPL_INIT_MINIMAL
3260 Arch init code should be built for a very small image
3262 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_PARTITION
3263 Partition on the MMC to load U-Boot from when the MMC is being
3266 CONFIG_SYS_MMCSD_RAW_MODE_KERNEL_SECTOR
3267 Sector to load kernel uImage from when MMC is being
3268 used in raw mode (for Falcon mode)
3270 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTOR,
3271 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTORS
3272 Sector and number of sectors to load kernel argument
3273 parameters from when MMC is being used in raw mode
3276 CONFIG_SYS_MMCSD_FS_BOOT_PARTITION
3277 Partition on the MMC to load U-Boot from when the MMC is being
3280 CONFIG_SPL_FS_LOAD_PAYLOAD_NAME
3281 Filename to read to load U-Boot when reading from filesystem
3283 CONFIG_SPL_FS_LOAD_KERNEL_NAME
3284 Filename to read to load kernel uImage when reading
3285 from filesystem (for Falcon mode)
3287 CONFIG_SPL_FS_LOAD_ARGS_NAME
3288 Filename to read to load kernel argument parameters
3289 when reading from filesystem (for Falcon mode)
3291 CONFIG_SPL_MPC83XX_WAIT_FOR_NAND
3292 Set this for NAND SPL on PPC mpc83xx targets, so that
3293 start.S waits for the rest of the SPL to load before
3294 continuing (the hardware starts execution after just
3295 loading the first page rather than the full 4K).
3297 CONFIG_SPL_SKIP_RELOCATE
3298 Avoid SPL relocation
3300 CONFIG_SPL_NAND_BASE
3301 Include nand_base.c in the SPL. Requires
3302 CONFIG_SPL_NAND_DRIVERS.
3304 CONFIG_SPL_NAND_DRIVERS
3305 SPL uses normal NAND drivers, not minimal drivers.
3308 Include standard software ECC in the SPL
3310 CONFIG_SPL_NAND_SIMPLE
3311 Support for NAND boot using simple NAND drivers that
3312 expose the cmd_ctrl() interface.
3315 Support for a lightweight UBI (fastmap) scanner and
3318 CONFIG_SPL_NAND_RAW_ONLY
3319 Support to boot only raw u-boot.bin images. Use this only
3320 if you need to save space.
3322 CONFIG_SPL_COMMON_INIT_DDR
3323 Set for common ddr init with serial presence detect in
3326 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
3327 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
3328 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
3329 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
3330 CONFIG_SYS_NAND_ECCBYTES
3331 Defines the size and behavior of the NAND that SPL uses
3334 CONFIG_SPL_NAND_BOOT
3335 Add support NAND boot
3337 CONFIG_SYS_NAND_U_BOOT_OFFS
3338 Location in NAND to read U-Boot from
3340 CONFIG_SYS_NAND_U_BOOT_DST
3341 Location in memory to load U-Boot to
3343 CONFIG_SYS_NAND_U_BOOT_SIZE
3344 Size of image to load
3346 CONFIG_SYS_NAND_U_BOOT_START
3347 Entry point in loaded image to jump to
3349 CONFIG_SYS_NAND_HW_ECC_OOBFIRST
3350 Define this if you need to first read the OOB and then the
3351 data. This is used, for example, on davinci platforms.
3353 CONFIG_SPL_OMAP3_ID_NAND
3354 Support for an OMAP3-specific set of functions to return the
3355 ID and MFR of the first attached NAND chip, if present.
3357 CONFIG_SPL_RAM_DEVICE
3358 Support for running image already present in ram, in SPL binary
3361 Image offset to which the SPL should be padded before appending
3362 the SPL payload. By default, this is defined as
3363 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3364 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3365 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3368 Final target image containing SPL and payload. Some SPLs
3369 use an arch-specific makefile fragment instead, for
3370 example if more than one image needs to be produced.
3372 CONFIG_FIT_SPL_PRINT
3373 Printing information about a FIT image adds quite a bit of
3374 code to SPL. So this is normally disabled in SPL. Use this
3375 option to re-enable it. This will affect the output of the
3376 bootm command when booting a FIT image.
3380 Enable building of TPL globally.
3383 Image offset to which the TPL should be padded before appending
3384 the TPL payload. By default, this is defined as
3385 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined.
3386 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL
3387 payload without any padding, or >= CONFIG_SPL_MAX_SIZE.
3389 - Interrupt support (PPC):
3391 There are common interrupt_init() and timer_interrupt()
3392 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
3393 for CPU specific initialization. interrupt_init_cpu()
3394 should set decrementer_count to appropriate value. If
3395 CPU resets decrementer automatically after interrupt
3396 (ppc4xx) it should set decrementer_count to zero.
3397 timer_interrupt() calls timer_interrupt_cpu() for CPU
3398 specific handling. If board has watchdog / status_led
3399 / other_activity_monitor it works automatically from
3400 general timer_interrupt().
3403 Board initialization settings:
3404 ------------------------------
3406 During Initialization u-boot calls a number of board specific functions
3407 to allow the preparation of board specific prerequisites, e.g. pin setup
3408 before drivers are initialized. To enable these callbacks the
3409 following configuration macros have to be defined. Currently this is
3410 architecture specific, so please check arch/your_architecture/lib/board.c
3411 typically in board_init_f() and board_init_r().
3413 - CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
3414 - CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
3415 - CONFIG_BOARD_LATE_INIT: Call board_late_init()
3416 - CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
3418 Configuration Settings:
3419 -----------------------
3421 - CONFIG_SYS_SUPPORT_64BIT_DATA: Defined automatically if compiled as 64-bit.
3422 Optionally it can be defined to support 64-bit memory commands.
3424 - CONFIG_SYS_LONGHELP: Defined when you want long help messages included;
3425 undefine this when you're short of memory.
3427 - CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default
3428 width of the commands listed in the 'help' command output.
3430 - CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to
3431 prompt for user input.
3433 - CONFIG_SYS_CBSIZE: Buffer size for input from the Console
3435 - CONFIG_SYS_PBSIZE: Buffer size for Console output
3437 - CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands
3439 - CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to
3440 the application (usually a Linux kernel) when it is
3443 - CONFIG_SYS_BAUDRATE_TABLE:
3444 List of legal baudrate settings for this board.
3446 - CONFIG_SYS_MEMTEST_START, CONFIG_SYS_MEMTEST_END:
3447 Begin and End addresses of the area used by the
3450 - CONFIG_SYS_ALT_MEMTEST:
3451 Enable an alternate, more extensive memory test.
3453 - CONFIG_SYS_MEMTEST_SCRATCH:
3454 Scratch address used by the alternate memory test
3455 You only need to set this if address zero isn't writeable
3457 - CONFIG_SYS_MEM_RESERVE_SECURE
3458 Only implemented for ARMv8 for now.
3459 If defined, the size of CONFIG_SYS_MEM_RESERVE_SECURE memory
3460 is substracted from total RAM and won't be reported to OS.
3461 This memory can be used as secure memory. A variable
3462 gd->arch.secure_ram is used to track the location. In systems
3463 the RAM base is not zero, or RAM is divided into banks,
3464 this variable needs to be recalcuated to get the address.
3466 - CONFIG_SYS_MEM_TOP_HIDE:
3467 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
3468 this specified memory area will get subtracted from the top
3469 (end) of RAM and won't get "touched" at all by U-Boot. By
3470 fixing up gd->ram_size the Linux kernel should gets passed
3471 the now "corrected" memory size and won't touch it either.
3472 This should work for arch/ppc and arch/powerpc. Only Linux
3473 board ports in arch/powerpc with bootwrapper support that
3474 recalculate the memory size from the SDRAM controller setup
3475 will have to get fixed in Linux additionally.
3477 This option can be used as a workaround for the 440EPx/GRx
3478 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
3481 WARNING: Please make sure that this value is a multiple of
3482 the Linux page size (normally 4k). If this is not the case,
3483 then the end address of the Linux memory will be located at a
3484 non page size aligned address and this could cause major
3487 - CONFIG_SYS_LOADS_BAUD_CHANGE:
3488 Enable temporary baudrate change while serial download
3490 - CONFIG_SYS_SDRAM_BASE:
3491 Physical start address of SDRAM. _Must_ be 0 here.
3493 - CONFIG_SYS_FLASH_BASE:
3494 Physical start address of Flash memory.
3496 - CONFIG_SYS_MONITOR_BASE:
3497 Physical start address of boot monitor code (set by
3498 make config files to be same as the text base address
3499 (CONFIG_SYS_TEXT_BASE) used when linking) - same as
3500 CONFIG_SYS_FLASH_BASE when booting from flash.
3502 - CONFIG_SYS_MONITOR_LEN:
3503 Size of memory reserved for monitor code, used to
3504 determine _at_compile_time_ (!) if the environment is
3505 embedded within the U-Boot image, or in a separate
3508 - CONFIG_SYS_MALLOC_LEN:
3509 Size of DRAM reserved for malloc() use.
3511 - CONFIG_SYS_MALLOC_F_LEN
3512 Size of the malloc() pool for use before relocation. If
3513 this is defined, then a very simple malloc() implementation
3514 will become available before relocation. The address is just
3515 below the global data, and the stack is moved down to make
3518 This feature allocates regions with increasing addresses
3519 within the region. calloc() is supported, but realloc()
3520 is not available. free() is supported but does nothing.
3521 The memory will be freed (or in fact just forgotten) when
3522 U-Boot relocates itself.
3524 - CONFIG_SYS_MALLOC_SIMPLE
3525 Provides a simple and small malloc() and calloc() for those
3526 boards which do not use the full malloc in SPL (which is
3527 enabled with CONFIG_SYS_SPL_MALLOC_START).
3529 - CONFIG_SYS_NONCACHED_MEMORY:
3530 Size of non-cached memory area. This area of memory will be
3531 typically located right below the malloc() area and mapped
3532 uncached in the MMU. This is useful for drivers that would
3533 otherwise require a lot of explicit cache maintenance. For
3534 some drivers it's also impossible to properly maintain the
3535 cache. For example if the regions that need to be flushed
3536 are not a multiple of the cache-line size, *and* padding
3537 cannot be allocated between the regions to align them (i.e.
3538 if the HW requires a contiguous array of regions, and the
3539 size of each region is not cache-aligned), then a flush of
3540 one region may result in overwriting data that hardware has
3541 written to another region in the same cache-line. This can
3542 happen for example in network drivers where descriptors for
3543 buffers are typically smaller than the CPU cache-line (e.g.
3544 16 bytes vs. 32 or 64 bytes).
3546 Non-cached memory is only supported on 32-bit ARM at present.
3548 - CONFIG_SYS_BOOTM_LEN:
3549 Normally compressed uImages are limited to an
3550 uncompressed size of 8 MBytes. If this is not enough,
3551 you can define CONFIG_SYS_BOOTM_LEN in your board config file
3552 to adjust this setting to your needs.
3554 - CONFIG_SYS_BOOTMAPSZ:
3555 Maximum size of memory mapped by the startup code of
3556 the Linux kernel; all data that must be processed by
3557 the Linux kernel (bd_info, boot arguments, FDT blob if
3558 used) must be put below this limit, unless "bootm_low"
3559 environment variable is defined and non-zero. In such case
3560 all data for the Linux kernel must be between "bootm_low"
3561 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment
3562 variable "bootm_mapsize" will override the value of
3563 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined,
3564 then the value in "bootm_size" will be used instead.
3566 - CONFIG_SYS_BOOT_RAMDISK_HIGH:
3567 Enable initrd_high functionality. If defined then the
3568 initrd_high feature is enabled and the bootm ramdisk subcommand
3571 - CONFIG_SYS_BOOT_GET_CMDLINE:
3572 Enables allocating and saving kernel cmdline in space between
3573 "bootm_low" and "bootm_low" + BOOTMAPSZ.
3575 - CONFIG_SYS_BOOT_GET_KBD:
3576 Enables allocating and saving a kernel copy of the bd_info in
3577 space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
3579 - CONFIG_SYS_MAX_FLASH_BANKS:
3580 Max number of Flash memory banks
3582 - CONFIG_SYS_MAX_FLASH_SECT:
3583 Max number of sectors on a Flash chip
3585 - CONFIG_SYS_FLASH_ERASE_TOUT:
3586 Timeout for Flash erase operations (in ms)
3588 - CONFIG_SYS_FLASH_WRITE_TOUT:
3589 Timeout for Flash write operations (in ms)
3591 - CONFIG_SYS_FLASH_LOCK_TOUT
3592 Timeout for Flash set sector lock bit operation (in ms)
3594 - CONFIG_SYS_FLASH_UNLOCK_TOUT
3595 Timeout for Flash clear lock bits operation (in ms)
3597 - CONFIG_SYS_FLASH_PROTECTION
3598 If defined, hardware flash sectors protection is used
3599 instead of U-Boot software protection.
3601 - CONFIG_SYS_DIRECT_FLASH_TFTP:
3603 Enable TFTP transfers directly to flash memory;
3604 without this option such a download has to be
3605 performed in two steps: (1) download to RAM, and (2)
3606 copy from RAM to flash.
3608 The two-step approach is usually more reliable, since
3609 you can check if the download worked before you erase
3610 the flash, but in some situations (when system RAM is
3611 too limited to allow for a temporary copy of the
3612 downloaded image) this option may be very useful.
3614 - CONFIG_SYS_FLASH_CFI:
3615 Define if the flash driver uses extra elements in the
3616 common flash structure for storing flash geometry.
3618 - CONFIG_FLASH_CFI_DRIVER
3619 This option also enables the building of the cfi_flash driver
3620 in the drivers directory
3622 - CONFIG_FLASH_CFI_MTD
3623 This option enables the building of the cfi_mtd driver
3624 in the drivers directory. The driver exports CFI flash
3627 - CONFIG_SYS_FLASH_USE_BUFFER_WRITE
3628 Use buffered writes to flash.
3630 - CONFIG_FLASH_SPANSION_S29WS_N
3631 s29ws-n MirrorBit flash has non-standard addresses for buffered
3634 - CONFIG_SYS_FLASH_QUIET_TEST
3635 If this option is defined, the common CFI flash doesn't
3636 print it's warning upon not recognized FLASH banks. This
3637 is useful, if some of the configured banks are only
3638 optionally available.
3640 - CONFIG_FLASH_SHOW_PROGRESS
3641 If defined (must be an integer), print out countdown
3642 digits and dots. Recommended value: 45 (9..1) for 80
3643 column displays, 15 (3..1) for 40 column displays.
3645 - CONFIG_FLASH_VERIFY
3646 If defined, the content of the flash (destination) is compared
3647 against the source after the write operation. An error message
3648 will be printed when the contents are not identical.
3649 Please note that this option is useless in nearly all cases,
3650 since such flash programming errors usually are detected earlier
3651 while unprotecting/erasing/programming. Please only enable
3652 this option if you really know what you are doing.
3654 - CONFIG_SYS_RX_ETH_BUFFER:
3655 Defines the number of Ethernet receive buffers. On some
3656 Ethernet controllers it is recommended to set this value
3657 to 8 or even higher (EEPRO100 or 405 EMAC), since all
3658 buffers can be full shortly after enabling the interface
3659 on high Ethernet traffic.
3660 Defaults to 4 if not defined.
3662 - CONFIG_ENV_MAX_ENTRIES
3664 Maximum number of entries in the hash table that is used
3665 internally to store the environment settings. The default
3666 setting is supposed to be generous and should work in most
3667 cases. This setting can be used to tune behaviour; see
3668 lib/hashtable.c for details.
3670 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3671 - CONFIG_ENV_FLAGS_LIST_STATIC
3672 Enable validation of the values given to environment variables when
3673 calling env set. Variables can be restricted to only decimal,
3674 hexadecimal, or boolean. If CONFIG_CMD_NET is also defined,
3675 the variables can also be restricted to IP address or MAC address.
3677 The format of the list is:
3678 type_attribute = [s|d|x|b|i|m]
3679 access_attribute = [a|r|o|c]
3680 attributes = type_attribute[access_attribute]
3681 entry = variable_name[:attributes]
3684 The type attributes are:
3685 s - String (default)
3688 b - Boolean ([1yYtT|0nNfF])
3692 The access attributes are:
3698 - CONFIG_ENV_FLAGS_LIST_DEFAULT
3699 Define this to a list (string) to define the ".flags"
3700 environment variable in the default or embedded environment.
3702 - CONFIG_ENV_FLAGS_LIST_STATIC
3703 Define this to a list (string) to define validation that
3704 should be done if an entry is not found in the ".flags"
3705 environment variable. To override a setting in the static
3706 list, simply add an entry for the same variable name to the
3709 If CONFIG_REGEX is defined, the variable_name above is evaluated as a
3710 regular expression. This allows multiple variables to define the same
3711 flags without explicitly listing them for each variable.
3713 - CONFIG_ENV_ACCESS_IGNORE_FORCE
3714 If defined, don't allow the -f switch to env set override variable
3717 - CONFIG_OMAP_PLATFORM_RESET_TIME_MAX_USEC (OMAP only)
3718 This is set by OMAP boards for the max time that reset should
3719 be asserted. See doc/README.omap-reset-time for details on how
3720 the value can be calculated on a given board.
3723 If stdint.h is available with your toolchain you can define this
3724 option to enable it. You can provide option 'USE_STDINT=1' when
3725 building U-Boot to enable this.
3727 The following definitions that deal with the placement and management
3728 of environment data (variable area); in general, we support the
3729 following configurations:
3731 - CONFIG_BUILD_ENVCRC:
3733 Builds up envcrc with the target environment so that external utils
3734 may easily extract it and embed it in final U-Boot images.
3736 - CONFIG_ENV_IS_IN_FLASH:
3738 Define this if the environment is in flash memory.
3740 a) The environment occupies one whole flash sector, which is
3741 "embedded" in the text segment with the U-Boot code. This
3742 happens usually with "bottom boot sector" or "top boot
3743 sector" type flash chips, which have several smaller
3744 sectors at the start or the end. For instance, such a
3745 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
3746 such a case you would place the environment in one of the
3747 4 kB sectors - with U-Boot code before and after it. With
3748 "top boot sector" type flash chips, you would put the
3749 environment in one of the last sectors, leaving a gap
3750 between U-Boot and the environment.
3752 - CONFIG_ENV_OFFSET:
3754 Offset of environment data (variable area) to the
3755 beginning of flash memory; for instance, with bottom boot
3756 type flash chips the second sector can be used: the offset
3757 for this sector is given here.
3759 CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
3763 This is just another way to specify the start address of
3764 the flash sector containing the environment (instead of
3767 - CONFIG_ENV_SECT_SIZE:
3769 Size of the sector containing the environment.
3772 b) Sometimes flash chips have few, equal sized, BIG sectors.
3773 In such a case you don't want to spend a whole sector for
3778 If you use this in combination with CONFIG_ENV_IS_IN_FLASH
3779 and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
3780 of this flash sector for the environment. This saves
3781 memory for the RAM copy of the environment.
3783 It may also save flash memory if you decide to use this
3784 when your environment is "embedded" within U-Boot code,
3785 since then the remainder of the flash sector could be used
3786 for U-Boot code. It should be pointed out that this is
3787 STRONGLY DISCOURAGED from a robustness point of view:
3788 updating the environment in flash makes it always
3789 necessary to erase the WHOLE sector. If something goes
3790 wrong before the contents has been restored from a copy in
3791 RAM, your target system will be dead.
3793 - CONFIG_ENV_ADDR_REDUND
3794 CONFIG_ENV_SIZE_REDUND
3796 These settings describe a second storage area used to hold
3797 a redundant copy of the environment data, so that there is
3798 a valid backup copy in case there is a power failure during
3799 a "saveenv" operation.
3801 BE CAREFUL! Any changes to the flash layout, and some changes to the
3802 source code will make it necessary to adapt <board>/u-boot.lds*
3806 - CONFIG_ENV_IS_IN_NVRAM:
3808 Define this if you have some non-volatile memory device
3809 (NVRAM, battery buffered SRAM) which you want to use for the
3815 These two #defines are used to determine the memory area you
3816 want to use for environment. It is assumed that this memory
3817 can just be read and written to, without any special
3820 BE CAREFUL! The first access to the environment happens quite early
3821 in U-Boot initialization (when we try to get the setting of for the
3822 console baudrate). You *MUST* have mapped your NVRAM area then, or
3825 Please note that even with NVRAM we still use a copy of the
3826 environment in RAM: we could work on NVRAM directly, but we want to
3827 keep settings there always unmodified except somebody uses "saveenv"
3828 to save the current settings.
3831 - CONFIG_ENV_IS_IN_EEPROM:
3833 Use this if you have an EEPROM or similar serial access
3834 device and a driver for it.
3836 - CONFIG_ENV_OFFSET:
3839 These two #defines specify the offset and size of the
3840 environment area within the total memory of your EEPROM.
3842 - CONFIG_SYS_I2C_EEPROM_ADDR:
3843 If defined, specified the chip address of the EEPROM device.
3844 The default address is zero.
3846 - CONFIG_SYS_I2C_EEPROM_BUS:
3847 If defined, specified the i2c bus of the EEPROM device.
3849 - CONFIG_SYS_EEPROM_PAGE_WRITE_BITS:
3850 If defined, the number of bits used to address bytes in a
3851 single page in the EEPROM device. A 64 byte page, for example
3852 would require six bits.
3854 - CONFIG_SYS_EEPROM_PAGE_WRITE_DELAY_MS:
3855 If defined, the number of milliseconds to delay between
3856 page writes. The default is zero milliseconds.
3858 - CONFIG_SYS_I2C_EEPROM_ADDR_LEN:
3859 The length in bytes of the EEPROM memory array address. Note
3860 that this is NOT the chip address length!
3862 - CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW:
3863 EEPROM chips that implement "address overflow" are ones
3864 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
3865 address and the extra bits end up in the "chip address" bit
3866 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
3869 Note that we consider the length of the address field to
3870 still be one byte because the extra address bits are hidden
3871 in the chip address.
3873 - CONFIG_SYS_EEPROM_SIZE:
3874 The size in bytes of the EEPROM device.
3876 - CONFIG_ENV_EEPROM_IS_ON_I2C
3877 define this, if you have I2C and SPI activated, and your
3878 EEPROM, which holds the environment, is on the I2C bus.
3880 - CONFIG_I2C_ENV_EEPROM_BUS
3881 if you have an Environment on an EEPROM reached over
3882 I2C muxes, you can define here, how to reach this
3883 EEPROM. For example:
3885 #define CONFIG_I2C_ENV_EEPROM_BUS 1
3887 EEPROM which holds the environment, is reached over
3888 a pca9547 i2c mux with address 0x70, channel 3.
3890 - CONFIG_ENV_IS_IN_DATAFLASH:
3892 Define this if you have a DataFlash memory device which you
3893 want to use for the environment.
3895 - CONFIG_ENV_OFFSET:
3899 These three #defines specify the offset and size of the
3900 environment area within the total memory of your DataFlash placed
3901 at the specified address.
3903 - CONFIG_ENV_IS_IN_SPI_FLASH:
3905 Define this if you have a SPI Flash memory device which you
3906 want to use for the environment.
3908 - CONFIG_ENV_OFFSET:
3911 These two #defines specify the offset and size of the
3912 environment area within the SPI Flash. CONFIG_ENV_OFFSET must be
3913 aligned to an erase sector boundary.
3915 - CONFIG_ENV_SECT_SIZE:
3917 Define the SPI flash's sector size.
3919 - CONFIG_ENV_OFFSET_REDUND (optional):
3921 This setting describes a second storage area of CONFIG_ENV_SIZE
3922 size used to hold a redundant copy of the environment data, so
3923 that there is a valid backup copy in case there is a power failure
3924 during a "saveenv" operation. CONFIG_ENV_OFFSET_REDUND must be
3925 aligned to an erase sector boundary.
3927 - CONFIG_ENV_SPI_BUS (optional):
3928 - CONFIG_ENV_SPI_CS (optional):
3930 Define the SPI bus and chip select. If not defined they will be 0.
3932 - CONFIG_ENV_SPI_MAX_HZ (optional):
3934 Define the SPI max work clock. If not defined then use 1MHz.
3936 - CONFIG_ENV_SPI_MODE (optional):
3938 Define the SPI work mode. If not defined then use SPI_MODE_3.
3940 - CONFIG_ENV_IS_IN_REMOTE:
3942 Define this if you have a remote memory space which you
3943 want to use for the local device's environment.
3948 These two #defines specify the address and size of the
3949 environment area within the remote memory space. The
3950 local device can get the environment from remote memory
3951 space by SRIO or PCIE links.
3953 BE CAREFUL! For some special cases, the local device can not use
3954 "saveenv" command. For example, the local device will get the
3955 environment stored in a remote NOR flash by SRIO or PCIE link,
3956 but it can not erase, write this NOR flash by SRIO or PCIE interface.
3958 - CONFIG_ENV_IS_IN_NAND:
3960 Define this if you have a NAND device which you want to use
3961 for the environment.
3963 - CONFIG_ENV_OFFSET:
3966 These two #defines specify the offset and size of the environment
3967 area within the first NAND device. CONFIG_ENV_OFFSET must be
3968 aligned to an erase block boundary.
3970 - CONFIG_ENV_OFFSET_REDUND (optional):
3972 This setting describes a second storage area of CONFIG_ENV_SIZE
3973 size used to hold a redundant copy of the environment data, so
3974 that there is a valid backup copy in case there is a power failure
3975 during a "saveenv" operation. CONFIG_ENV_OFFSET_REDUND must be
3976 aligned to an erase block boundary.
3978 - CONFIG_ENV_RANGE (optional):
3980 Specifies the length of the region in which the environment
3981 can be written. This should be a multiple of the NAND device's
3982 block size. Specifying a range with more erase blocks than
3983 are needed to hold CONFIG_ENV_SIZE allows bad blocks within
3984 the range to be avoided.
3986 - CONFIG_ENV_OFFSET_OOB (optional):
3988 Enables support for dynamically retrieving the offset of the
3989 environment from block zero's out-of-band data. The
3990 "nand env.oob" command can be used to record this offset.
3991 Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
3992 using CONFIG_ENV_OFFSET_OOB.
3994 - CONFIG_NAND_ENV_DST
3996 Defines address in RAM to which the nand_spl code should copy the
3997 environment. If redundant environment is used, it will be copied to
3998 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
4000 - CONFIG_ENV_IS_IN_UBI:
4002 Define this if you have an UBI volume that you want to use for the
4003 environment. This has the benefit of wear-leveling the environment
4004 accesses, which is important on NAND.
4006 - CONFIG_ENV_UBI_PART:
4008 Define this to a string that is the mtd partition containing the UBI.
4010 - CONFIG_ENV_UBI_VOLUME:
4012 Define this to the name of the volume that you want to store the
4015 - CONFIG_ENV_UBI_VOLUME_REDUND:
4017 Define this to the name of another volume to store a second copy of
4018 the environment in. This will enable redundant environments in UBI.
4019 It is assumed that both volumes are in the same MTD partition.
4021 - CONFIG_UBI_SILENCE_MSG
4022 - CONFIG_UBIFS_SILENCE_MSG
4024 You will probably want to define these to avoid a really noisy system
4025 when storing the env in UBI.
4027 - CONFIG_ENV_IS_IN_FAT:
4028 Define this if you want to use the FAT file system for the environment.
4030 - FAT_ENV_INTERFACE:
4032 Define this to a string that is the name of the block device.
4034 - FAT_ENV_DEVICE_AND_PART:
4036 Define this to a string to specify the partition of the device. It can
4039 "D:P", "D:0", "D", "D:" or "D:auto" (D, P are integers. And P >= 1)
4040 - "D:P": device D partition P. Error occurs if device D has no
4043 - "D" or "D:": device D partition 1 if device D has partition
4044 table, or the whole device D if has no partition
4046 - "D:auto": first partition in device D with bootable flag set.
4047 If none, first valid partition in device D. If no
4048 partition table then means device D.
4052 It's a string of the FAT file name. This file use to store the
4056 This should be defined. Otherwise it cannot save the environment file.
4058 - CONFIG_ENV_IS_IN_MMC:
4060 Define this if you have an MMC device which you want to use for the
4063 - CONFIG_SYS_MMC_ENV_DEV:
4065 Specifies which MMC device the environment is stored in.
4067 - CONFIG_SYS_MMC_ENV_PART (optional):
4069 Specifies which MMC partition the environment is stored in. If not
4070 set, defaults to partition 0, the user area. Common values might be
4071 1 (first MMC boot partition), 2 (second MMC boot partition).
4073 - CONFIG_ENV_OFFSET:
4076 These two #defines specify the offset and size of the environment
4077 area within the specified MMC device.
4079 If offset is positive (the usual case), it is treated as relative to
4080 the start of the MMC partition. If offset is negative, it is treated
4081 as relative to the end of the MMC partition. This can be useful if
4082 your board may be fitted with different MMC devices, which have
4083 different sizes for the MMC partitions, and you always want the
4084 environment placed at the very end of the partition, to leave the
4085 maximum possible space before it, to store other data.
4087 These two values are in units of bytes, but must be aligned to an
4088 MMC sector boundary.
4090 - CONFIG_ENV_OFFSET_REDUND (optional):
4092 Specifies a second storage area, of CONFIG_ENV_SIZE size, used to
4093 hold a redundant copy of the environment data. This provides a
4094 valid backup copy in case the other copy is corrupted, e.g. due
4095 to a power failure during a "saveenv" operation.
4097 This value may also be positive or negative; this is handled in the
4098 same way as CONFIG_ENV_OFFSET.
4100 This value is also in units of bytes, but must also be aligned to
4101 an MMC sector boundary.
4103 - CONFIG_ENV_SIZE_REDUND (optional):
4105 This value need not be set, even when CONFIG_ENV_OFFSET_REDUND is
4106 set. If this value is set, it must be set to the same value as
4109 - CONFIG_SYS_SPI_INIT_OFFSET
4111 Defines offset to the initial SPI buffer area in DPRAM. The
4112 area is used at an early stage (ROM part) if the environment
4113 is configured to reside in the SPI EEPROM: We need a 520 byte
4114 scratch DPRAM area. It is used between the two initialization
4115 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
4116 to be a good choice since it makes it far enough from the
4117 start of the data area as well as from the stack pointer.
4119 Please note that the environment is read-only until the monitor
4120 has been relocated to RAM and a RAM copy of the environment has been
4121 created; also, when using EEPROM you will have to use getenv_f()
4122 until then to read environment variables.
4124 The environment is protected by a CRC32 checksum. Before the monitor
4125 is relocated into RAM, as a result of a bad CRC you will be working
4126 with the compiled-in default environment - *silently*!!! [This is
4127 necessary, because the first environment variable we need is the
4128 "baudrate" setting for the console - if we have a bad CRC, we don't
4129 have any device yet where we could complain.]
4131 Note: once the monitor has been relocated, then it will complain if
4132 the default environment is used; a new CRC is computed as soon as you
4133 use the "saveenv" command to store a valid environment.
4135 - CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
4136 Echo the inverted Ethernet link state to the fault LED.
4138 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
4139 also needs to be defined.
4141 - CONFIG_SYS_FAULT_MII_ADDR:
4142 MII address of the PHY to check for the Ethernet link state.
4144 - CONFIG_NS16550_MIN_FUNCTIONS:
4145 Define this if you desire to only have use of the NS16550_init
4146 and NS16550_putc functions for the serial driver located at
4147 drivers/serial/ns16550.c. This option is useful for saving
4148 space for already greatly restricted images, including but not
4149 limited to NAND_SPL configurations.
4151 - CONFIG_DISPLAY_BOARDINFO
4152 Display information about the board that U-Boot is running on
4153 when U-Boot starts up. The board function checkboard() is called
4156 - CONFIG_DISPLAY_BOARDINFO_LATE
4157 Similar to the previous option, but display this information
4158 later, once stdio is running and output goes to the LCD, if
4161 - CONFIG_BOARD_SIZE_LIMIT:
4162 Maximum size of the U-Boot image. When defined, the
4163 build system checks that the actual size does not
4166 Low Level (hardware related) configuration options:
4167 ---------------------------------------------------
4169 - CONFIG_SYS_CACHELINE_SIZE:
4170 Cache Line Size of the CPU.
4172 - CONFIG_SYS_DEFAULT_IMMR:
4173 Default address of the IMMR after system reset.
4175 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
4176 and RPXsuper) to be able to adjust the position of
4177 the IMMR register after a reset.
4179 - CONFIG_SYS_CCSRBAR_DEFAULT:
4180 Default (power-on reset) physical address of CCSR on Freescale
4183 - CONFIG_SYS_CCSRBAR:
4184 Virtual address of CCSR. On a 32-bit build, this is typically
4185 the same value as CONFIG_SYS_CCSRBAR_DEFAULT.
4187 CONFIG_SYS_DEFAULT_IMMR must also be set to this value,
4188 for cross-platform code that uses that macro instead.
4190 - CONFIG_SYS_CCSRBAR_PHYS:
4191 Physical address of CCSR. CCSR can be relocated to a new
4192 physical address, if desired. In this case, this macro should
4193 be set to that address. Otherwise, it should be set to the
4194 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR
4195 is typically relocated on 36-bit builds. It is recommended
4196 that this macro be defined via the _HIGH and _LOW macros:
4198 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH
4199 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW)
4201 - CONFIG_SYS_CCSRBAR_PHYS_HIGH:
4202 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically
4203 either 0 (32-bit build) or 0xF (36-bit build). This macro is
4204 used in assembly code, so it must not contain typecasts or
4205 integer size suffixes (e.g. "ULL").
4207 - CONFIG_SYS_CCSRBAR_PHYS_LOW:
4208 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is
4209 used in assembly code, so it must not contain typecasts or
4210 integer size suffixes (e.g. "ULL").
4212 - CONFIG_SYS_CCSR_DO_NOT_RELOCATE:
4213 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
4214 forced to a value that ensures that CCSR is not relocated.
4216 - Floppy Disk Support:
4217 CONFIG_SYS_FDC_DRIVE_NUMBER
4219 the default drive number (default value 0)
4221 CONFIG_SYS_ISA_IO_STRIDE
4223 defines the spacing between FDC chipset registers
4226 CONFIG_SYS_ISA_IO_OFFSET
4228 defines the offset of register from address. It
4229 depends on which part of the data bus is connected to
4230 the FDC chipset. (default value 0)
4232 If CONFIG_SYS_ISA_IO_STRIDE CONFIG_SYS_ISA_IO_OFFSET and
4233 CONFIG_SYS_FDC_DRIVE_NUMBER are undefined, they take their
4236 if CONFIG_SYS_FDC_HW_INIT is defined, then the function
4237 fdc_hw_init() is called at the beginning of the FDC
4238 setup. fdc_hw_init() must be provided by the board
4239 source code. It is used to make hardware-dependent
4243 Most IDE controllers were designed to be connected with PCI
4244 interface. Only few of them were designed for AHB interface.
4245 When software is doing ATA command and data transfer to
4246 IDE devices through IDE-AHB controller, some additional
4247 registers accessing to these kind of IDE-AHB controller
4250 - CONFIG_SYS_IMMR: Physical address of the Internal Memory.
4251 DO NOT CHANGE unless you know exactly what you're
4252 doing! (11-4) [MPC8xx/82xx systems only]
4254 - CONFIG_SYS_INIT_RAM_ADDR:
4256 Start address of memory area that can be used for
4257 initial data and stack; please note that this must be
4258 writable memory that is working WITHOUT special
4259 initialization, i. e. you CANNOT use normal RAM which
4260 will become available only after programming the
4261 memory controller and running certain initialization
4264 U-Boot uses the following memory types:
4265 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
4266 - MPC824X: data cache
4267 - PPC4xx: data cache
4269 - CONFIG_SYS_GBL_DATA_OFFSET:
4271 Offset of the initial data structure in the memory
4272 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually
4273 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial
4274 data is located at the end of the available space
4275 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE -
4276 GENERATED_GBL_DATA_SIZE), and the initial stack is just
4277 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR +
4278 CONFIG_SYS_GBL_DATA_OFFSET) downward.
4281 On the MPC824X (or other systems that use the data
4282 cache for initial memory) the address chosen for
4283 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must
4284 point to an otherwise UNUSED address space between
4285 the top of RAM and the start of the PCI space.
4287 - CONFIG_SYS_SIUMCR: SIU Module Configuration (11-6)
4289 - CONFIG_SYS_SYPCR: System Protection Control (11-9)
4291 - CONFIG_SYS_TBSCR: Time Base Status and Control (11-26)
4293 - CONFIG_SYS_PISCR: Periodic Interrupt Status and Control (11-31)
4295 - CONFIG_SYS_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
4297 - CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27)
4299 - CONFIG_SYS_OR_TIMING_SDRAM:
4302 - CONFIG_SYS_MAMR_PTA:
4303 periodic timer for refresh
4305 - CONFIG_SYS_DER: Debug Event Register (37-47)
4307 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
4308 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
4309 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
4310 CONFIG_SYS_BR1_PRELIM:
4311 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
4313 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
4314 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
4315 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
4316 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
4318 - CONFIG_SYS_MAMR_PTA, CONFIG_SYS_MPTPR_2BK_4K, CONFIG_SYS_MPTPR_1BK_4K, CONFIG_SYS_MPTPR_2BK_8K,
4319 CONFIG_SYS_MPTPR_1BK_8K, CONFIG_SYS_MAMR_8COL, CONFIG_SYS_MAMR_9COL:
4320 Machine Mode Register and Memory Periodic Timer
4321 Prescaler definitions (SDRAM timing)
4323 - CONFIG_SYS_I2C_UCODE_PATCH, CONFIG_SYS_I2C_DPMEM_OFFSET [0x1FC0]:
4324 enable I2C microcode relocation patch (MPC8xx);
4325 define relocation offset in DPRAM [DSP2]
4327 - CONFIG_SYS_SMC_UCODE_PATCH, CONFIG_SYS_SMC_DPMEM_OFFSET [0x1FC0]:
4328 enable SMC microcode relocation patch (MPC8xx);
4329 define relocation offset in DPRAM [SMC1]
4331 - CONFIG_SYS_SPI_UCODE_PATCH, CONFIG_SYS_SPI_DPMEM_OFFSET [0x1FC0]:
4332 enable SPI microcode relocation patch (MPC8xx);
4333 define relocation offset in DPRAM [SCC4]
4335 - CONFIG_SYS_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
4336 Offset of the bootmode word in DPRAM used by post
4337 (Power On Self Tests). This definition overrides
4338 #define'd default value in commproc.h resp.
4341 - CONFIG_SYS_PCI_SLV_MEM_LOCAL, CONFIG_SYS_PCI_SLV_MEM_BUS, CONFIG_SYS_PICMR0_MASK_ATTRIB,
4342 CONFIG_SYS_PCI_MSTR0_LOCAL, CONFIG_SYS_PCIMSK0_MASK, CONFIG_SYS_PCI_MSTR1_LOCAL,
4343 CONFIG_SYS_PCIMSK1_MASK, CONFIG_SYS_PCI_MSTR_MEM_LOCAL, CONFIG_SYS_PCI_MSTR_MEM_BUS,
4344 CONFIG_SYS_CPU_PCI_MEM_START, CONFIG_SYS_PCI_MSTR_MEM_SIZE, CONFIG_SYS_POCMR0_MASK_ATTRIB,
4345 CONFIG_SYS_PCI_MSTR_MEMIO_LOCAL, CONFIG_SYS_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
4346 CONFIG_SYS_PCI_MSTR_MEMIO_SIZE, CONFIG_SYS_POCMR1_MASK_ATTRIB, CONFIG_SYS_PCI_MSTR_IO_LOCAL,
4347 CONFIG_SYS_PCI_MSTR_IO_BUS, CONFIG_SYS_CPU_PCI_IO_START, CONFIG_SYS_PCI_MSTR_IO_SIZE,
4348 CONFIG_SYS_POCMR2_MASK_ATTRIB: (MPC826x only)
4349 Overrides the default PCI memory map in arch/powerpc/cpu/mpc8260/pci.c if set.
4351 - CONFIG_PCI_DISABLE_PCIE:
4352 Disable PCI-Express on systems where it is supported but not
4355 - CONFIG_PCI_ENUM_ONLY
4356 Only scan through and get the devices on the buses.
4357 Don't do any setup work, presumably because someone or
4358 something has already done it, and we don't need to do it
4359 a second time. Useful for platforms that are pre-booted
4360 by coreboot or similar.
4362 - CONFIG_PCI_INDIRECT_BRIDGE:
4363 Enable support for indirect PCI bridges.
4366 Chip has SRIO or not
4369 Board has SRIO 1 port available
4372 Board has SRIO 2 port available
4374 - CONFIG_SRIO_PCIE_BOOT_MASTER
4375 Board can support master function for Boot from SRIO and PCIE
4377 - CONFIG_SYS_SRIOn_MEM_VIRT:
4378 Virtual Address of SRIO port 'n' memory region
4380 - CONFIG_SYS_SRIOn_MEM_PHYS:
4381 Physical Address of SRIO port 'n' memory region
4383 - CONFIG_SYS_SRIOn_MEM_SIZE:
4384 Size of SRIO port 'n' memory region
4386 - CONFIG_SYS_NAND_BUSWIDTH_16BIT
4387 Defined to tell the NAND controller that the NAND chip is using
4389 Not all NAND drivers use this symbol.
4390 Example of drivers that use it:
4391 - drivers/mtd/nand/ndfc.c
4392 - drivers/mtd/nand/mxc_nand.c
4394 - CONFIG_SYS_NDFC_EBC0_CFG
4395 Sets the EBC0_CFG register for the NDFC. If not defined
4396 a default value will be used.
4399 Get DDR timing information from an I2C EEPROM. Common
4400 with pluggable memory modules such as SODIMMs
4403 I2C address of the SPD EEPROM
4405 - CONFIG_SYS_SPD_BUS_NUM
4406 If SPD EEPROM is on an I2C bus other than the first
4407 one, specify here. Note that the value must resolve
4408 to something your driver can deal with.
4410 - CONFIG_SYS_DDR_RAW_TIMING
4411 Get DDR timing information from other than SPD. Common with
4412 soldered DDR chips onboard without SPD. DDR raw timing
4413 parameters are extracted from datasheet and hard-coded into
4414 header files or board specific files.
4416 - CONFIG_FSL_DDR_INTERACTIVE
4417 Enable interactive DDR debugging. See doc/README.fsl-ddr.
4419 - CONFIG_FSL_DDR_SYNC_REFRESH
4420 Enable sync of refresh for multiple controllers.
4422 - CONFIG_FSL_DDR_BIST
4423 Enable built-in memory test for Freescale DDR controllers.
4425 - CONFIG_SYS_83XX_DDR_USES_CS0
4426 Only for 83xx systems. If specified, then DDR should
4427 be configured using CS0 and CS1 instead of CS2 and CS3.
4429 - CONFIG_ETHER_ON_FEC[12]
4430 Define to enable FEC[12] on a 8xx series processor.
4432 - CONFIG_FEC[12]_PHY
4433 Define to the hardcoded PHY address which corresponds
4434 to the given FEC; i. e.
4435 #define CONFIG_FEC1_PHY 4
4436 means that the PHY with address 4 is connected to FEC1
4438 When set to -1, means to probe for first available.
4440 - CONFIG_FEC[12]_PHY_NORXERR
4441 The PHY does not have a RXERR line (RMII only).
4442 (so program the FEC to ignore it).
4445 Enable RMII mode for all FECs.
4446 Note that this is a global option, we can't
4447 have one FEC in standard MII mode and another in RMII mode.
4449 - CONFIG_CRC32_VERIFY
4450 Add a verify option to the crc32 command.
4453 => crc32 -v <address> <count> <crc32>
4455 Where address/count indicate a memory area
4456 and crc32 is the correct crc32 which the
4460 Add the "loopw" memory command. This only takes effect if
4461 the memory commands are activated globally (CONFIG_CMD_MEM).
4464 Add the "mdc" and "mwc" memory commands. These are cyclic
4469 This command will print 4 bytes (10,11,12,13) each 500 ms.
4471 => mwc.l 100 12345678 10
4472 This command will write 12345678 to address 100 all 10 ms.
4474 This only takes effect if the memory commands are activated
4475 globally (CONFIG_CMD_MEM).
4477 - CONFIG_SKIP_LOWLEVEL_INIT
4478 [ARM, NDS32, MIPS only] If this variable is defined, then certain
4479 low level initializations (like setting up the memory
4480 controller) are omitted and/or U-Boot does not
4481 relocate itself into RAM.
4483 Normally this variable MUST NOT be defined. The only
4484 exception is when U-Boot is loaded (to RAM) by some
4485 other boot loader or by a debugger which performs
4486 these initializations itself.
4488 - CONFIG_SKIP_LOWLEVEL_INIT_ONLY
4489 [ARM926EJ-S only] This allows just the call to lowlevel_init()
4490 to be skipped. The normal CP15 init (such as enabling the
4491 instruction cache) is still performed.
4494 Modifies the behaviour of start.S when compiling a loader
4495 that is executed before the actual U-Boot. E.g. when
4496 compiling a NAND SPL.
4499 Modifies the behaviour of start.S when compiling a loader
4500 that is executed after the SPL and before the actual U-Boot.
4501 It is loaded by the SPL.
4503 - CONFIG_SYS_MPC85XX_NO_RESETVEC
4504 Only for 85xx systems. If this variable is specified, the section
4505 .resetvec is not kept and the section .bootpg is placed in the
4506 previous 4k of the .text section.
4508 - CONFIG_ARCH_MAP_SYSMEM
4509 Generally U-Boot (and in particular the md command) uses
4510 effective address. It is therefore not necessary to regard
4511 U-Boot address as virtual addresses that need to be translated
4512 to physical addresses. However, sandbox requires this, since
4513 it maintains its own little RAM buffer which contains all
4514 addressable memory. This option causes some memory accesses
4515 to be mapped through map_sysmem() / unmap_sysmem().
4517 - CONFIG_X86_RESET_VECTOR
4518 If defined, the x86 reset vector code is included. This is not
4519 needed when U-Boot is running from Coreboot.
4522 Defines the MPU clock speed (in MHz).
4524 NOTE : currently only supported on AM335x platforms.
4526 - CONFIG_SPL_AM33XX_ENABLE_RTC32K_OSC:
4527 Enables the RTC32K OSC on AM33xx based plattforms
4529 - CONFIG_SYS_NAND_NO_SUBPAGE_WRITE
4530 Option to disable subpage write in NAND driver
4531 driver that uses this:
4532 drivers/mtd/nand/davinci_nand.c
4534 Freescale QE/FMAN Firmware Support:
4535 -----------------------------------
4537 The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
4538 loading of "firmware", which is encoded in the QE firmware binary format.
4539 This firmware often needs to be loaded during U-Boot booting, so macros
4540 are used to identify the storage device (NOR flash, SPI, etc) and the address
4543 - CONFIG_SYS_FMAN_FW_ADDR
4544 The address in the storage device where the FMAN microcode is located. The
4545 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4548 - CONFIG_SYS_QE_FW_ADDR
4549 The address in the storage device where the QE microcode is located. The
4550 meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
4553 - CONFIG_SYS_QE_FMAN_FW_LENGTH
4554 The maximum possible size of the firmware. The firmware binary format
4555 has a field that specifies the actual size of the firmware, but it
4556 might not be possible to read any part of the firmware unless some
4557 local storage is allocated to hold the entire firmware first.
4559 - CONFIG_SYS_QE_FMAN_FW_IN_NOR
4560 Specifies that QE/FMAN firmware is located in NOR flash, mapped as
4561 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the
4562 virtual address in NOR flash.
4564 - CONFIG_SYS_QE_FMAN_FW_IN_NAND
4565 Specifies that QE/FMAN firmware is located in NAND flash.
4566 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
4568 - CONFIG_SYS_QE_FMAN_FW_IN_MMC
4569 Specifies that QE/FMAN firmware is located on the primary SD/MMC
4570 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
4572 - CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
4573 Specifies that QE/FMAN firmware is located in the remote (master)
4574 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
4575 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound
4576 window->master inbound window->master LAW->the ucode address in
4577 master's memory space.
4579 Freescale Layerscape Management Complex Firmware Support:
4580 ---------------------------------------------------------
4581 The Freescale Layerscape Management Complex (MC) supports the loading of
4583 This firmware often needs to be loaded during U-Boot booting, so macros
4584 are used to identify the storage device (NOR flash, SPI, etc) and the address
4587 - CONFIG_FSL_MC_ENET
4588 Enable the MC driver for Layerscape SoCs.
4590 Freescale Layerscape Debug Server Support:
4591 -------------------------------------------
4592 The Freescale Layerscape Debug Server Support supports the loading of
4593 "Debug Server firmware" and triggering SP boot-rom.
4594 This firmware often needs to be loaded during U-Boot booting.
4596 - CONFIG_SYS_MC_RSV_MEM_ALIGN
4597 Define alignment of reserved memory MC requires
4602 In order to achieve reproducible builds, timestamps used in the U-Boot build
4603 process have to be set to a fixed value.
4605 This is done using the SOURCE_DATE_EPOCH environment variable.
4606 SOURCE_DATE_EPOCH is to be set on the build host's shell, not as a configuration
4607 option for U-Boot or an environment variable in U-Boot.
4609 SOURCE_DATE_EPOCH should be set to a number of seconds since the epoch, in UTC.
4611 Building the Software:
4612 ======================
4614 Building U-Boot has been tested in several native build environments
4615 and in many different cross environments. Of course we cannot support
4616 all possibly existing versions of cross development tools in all
4617 (potentially obsolete) versions. In case of tool chain problems we
4618 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
4619 which is extensively used to build and test U-Boot.
4621 If you are not using a native environment, it is assumed that you
4622 have GNU cross compiling tools available in your path. In this case,
4623 you must set the environment variable CROSS_COMPILE in your shell.
4624 Note that no changes to the Makefile or any other source files are
4625 necessary. For example using the ELDK on a 4xx CPU, please enter:
4627 $ CROSS_COMPILE=ppc_4xx-
4628 $ export CROSS_COMPILE
4630 Note: If you wish to generate Windows versions of the utilities in
4631 the tools directory you can use the MinGW toolchain
4632 (http://www.mingw.org). Set your HOST tools to the MinGW
4633 toolchain and execute 'make tools'. For example:
4635 $ make HOSTCC=i586-mingw32msvc-gcc HOSTSTRIP=i586-mingw32msvc-strip tools
4637 Binaries such as tools/mkimage.exe will be created which can
4638 be executed on computers running Windows.
4640 U-Boot is intended to be simple to build. After installing the
4641 sources you must configure U-Boot for one specific board type. This
4646 where "NAME_defconfig" is the name of one of the existing configu-
4647 rations; see boards.cfg for supported names.
4649 Note: for some board special configuration names may exist; check if
4650 additional information is available from the board vendor; for
4651 instance, the TQM823L systems are available without (standard)
4652 or with LCD support. You can select such additional "features"
4653 when choosing the configuration, i. e.
4655 make TQM823L_defconfig
4656 - will configure for a plain TQM823L, i. e. no LCD support
4658 make TQM823L_LCD_defconfig
4659 - will configure for a TQM823L with U-Boot console on LCD
4664 Finally, type "make all", and you should get some working U-Boot
4665 images ready for download to / installation on your system:
4667 - "u-boot.bin" is a raw binary image
4668 - "u-boot" is an image in ELF binary format
4669 - "u-boot.srec" is in Motorola S-Record format
4671 By default the build is performed locally and the objects are saved
4672 in the source directory. One of the two methods can be used to change
4673 this behavior and build U-Boot to some external directory:
4675 1. Add O= to the make command line invocations:
4677 make O=/tmp/build distclean
4678 make O=/tmp/build NAME_defconfig
4679 make O=/tmp/build all
4681 2. Set environment variable KBUILD_OUTPUT to point to the desired location:
4683 export KBUILD_OUTPUT=/tmp/build
4688 Note that the command line "O=" setting overrides the KBUILD_OUTPUT environment
4692 Please be aware that the Makefiles assume you are using GNU make, so
4693 for instance on NetBSD you might need to use "gmake" instead of
4697 If the system board that you have is not listed, then you will need
4698 to port U-Boot to your hardware platform. To do this, follow these
4701 1. Create a new directory to hold your board specific code. Add any
4702 files you need. In your board directory, you will need at least
4703 the "Makefile" and a "<board>.c".
4704 2. Create a new configuration file "include/configs/<board>.h" for
4706 3. If you're porting U-Boot to a new CPU, then also create a new
4707 directory to hold your CPU specific code. Add any files you need.
4708 4. Run "make <board>_defconfig" with your new name.
4709 5. Type "make", and you should get a working "u-boot.srec" file
4710 to be installed on your target system.
4711 6. Debug and solve any problems that might arise.
4712 [Of course, this last step is much harder than it sounds.]
4715 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
4716 ==============================================================
4718 If you have modified U-Boot sources (for instance added a new board
4719 or support for new devices, a new CPU, etc.) you are expected to
4720 provide feedback to the other developers. The feedback normally takes
4721 the form of a "patch", i. e. a context diff against a certain (latest
4722 official or latest in the git repository) version of U-Boot sources.
4724 But before you submit such a patch, please verify that your modifi-
4725 cation did not break existing code. At least make sure that *ALL* of
4726 the supported boards compile WITHOUT ANY compiler warnings. To do so,
4727 just run the buildman script (tools/buildman/buildman), which will
4728 configure and build U-Boot for ALL supported system. Be warned, this
4729 will take a while. Please see the buildman README, or run 'buildman -H'
4733 See also "U-Boot Porting Guide" below.
4736 Monitor Commands - Overview:
4737 ============================
4739 go - start application at address 'addr'
4740 run - run commands in an environment variable
4741 bootm - boot application image from memory
4742 bootp - boot image via network using BootP/TFTP protocol
4743 bootz - boot zImage from memory
4744 tftpboot- boot image via network using TFTP protocol
4745 and env variables "ipaddr" and "serverip"
4746 (and eventually "gatewayip")
4747 tftpput - upload a file via network using TFTP protocol
4748 rarpboot- boot image via network using RARP/TFTP protocol
4749 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
4750 loads - load S-Record file over serial line
4751 loadb - load binary file over serial line (kermit mode)
4753 mm - memory modify (auto-incrementing)
4754 nm - memory modify (constant address)
4755 mw - memory write (fill)
4757 cmp - memory compare
4758 crc32 - checksum calculation
4759 i2c - I2C sub-system
4760 sspi - SPI utility commands
4761 base - print or set address offset
4762 printenv- print environment variables
4763 setenv - set environment variables
4764 saveenv - save environment variables to persistent storage
4765 protect - enable or disable FLASH write protection
4766 erase - erase FLASH memory
4767 flinfo - print FLASH memory information
4768 nand - NAND memory operations (see doc/README.nand)
4769 bdinfo - print Board Info structure
4770 iminfo - print header information for application image
4771 coninfo - print console devices and informations
4772 ide - IDE sub-system
4773 loop - infinite loop on address range
4774 loopw - infinite write loop on address range
4775 mtest - simple RAM test
4776 icache - enable or disable instruction cache
4777 dcache - enable or disable data cache
4778 reset - Perform RESET of the CPU
4779 echo - echo args to console
4780 version - print monitor version
4781 help - print online help
4782 ? - alias for 'help'
4785 Monitor Commands - Detailed Description:
4786 ========================================
4790 For now: just type "help <command>".
4793 Environment Variables:
4794 ======================
4796 U-Boot supports user configuration using Environment Variables which
4797 can be made persistent by saving to Flash memory.
4799 Environment Variables are set using "setenv", printed using
4800 "printenv", and saved to Flash using "saveenv". Using "setenv"
4801 without a value can be used to delete a variable from the
4802 environment. As long as you don't save the environment you are
4803 working with an in-memory copy. In case the Flash area containing the
4804 environment is erased by accident, a default environment is provided.
4806 Some configuration options can be set using Environment Variables.
4808 List of environment variables (most likely not complete):
4810 baudrate - see CONFIG_BAUDRATE
4812 bootdelay - see CONFIG_BOOTDELAY
4814 bootcmd - see CONFIG_BOOTCOMMAND
4816 bootargs - Boot arguments when booting an RTOS image
4818 bootfile - Name of the image to load with TFTP
4820 bootm_low - Memory range available for image processing in the bootm
4821 command can be restricted. This variable is given as
4822 a hexadecimal number and defines lowest address allowed
4823 for use by the bootm command. See also "bootm_size"
4824 environment variable. Address defined by "bootm_low" is
4825 also the base of the initial memory mapping for the Linux
4826 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
4829 bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
4830 This variable is given as a hexadecimal number and it
4831 defines the size of the memory region starting at base
4832 address bootm_low that is accessible by the Linux kernel
4833 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
4834 as the default value if it is defined, and bootm_size is
4837 bootm_size - Memory range available for image processing in the bootm
4838 command can be restricted. This variable is given as
4839 a hexadecimal number and defines the size of the region
4840 allowed for use by the bootm command. See also "bootm_low"
4841 environment variable.
4843 updatefile - Location of the software update file on a TFTP server, used
4844 by the automatic software update feature. Please refer to
4845 documentation in doc/README.update for more details.
4847 autoload - if set to "no" (any string beginning with 'n'),
4848 "bootp" will just load perform a lookup of the
4849 configuration from the BOOTP server, but not try to
4850 load any image using TFTP
4852 autostart - if set to "yes", an image loaded using the "bootp",
4853 "rarpboot", "tftpboot" or "diskboot" commands will
4854 be automatically started (by internally calling
4857 If set to "no", a standalone image passed to the
4858 "bootm" command will be copied to the load address
4859 (and eventually uncompressed), but NOT be started.
4860 This can be used to load and uncompress arbitrary
4863 fdt_high - if set this restricts the maximum address that the
4864 flattened device tree will be copied into upon boot.
4865 For example, if you have a system with 1 GB memory
4866 at physical address 0x10000000, while Linux kernel
4867 only recognizes the first 704 MB as low memory, you
4868 may need to set fdt_high as 0x3C000000 to have the
4869 device tree blob be copied to the maximum address
4870 of the 704 MB low memory, so that Linux kernel can
4871 access it during the boot procedure.
4873 If this is set to the special value 0xFFFFFFFF then
4874 the fdt will not be copied at all on boot. For this
4875 to work it must reside in writable memory, have
4876 sufficient padding on the end of it for u-boot to
4877 add the information it needs into it, and the memory
4878 must be accessible by the kernel.
4880 fdtcontroladdr- if set this is the address of the control flattened
4881 device tree used by U-Boot when CONFIG_OF_CONTROL is
4884 i2cfast - (PPC405GP|PPC405EP only)
4885 if set to 'y' configures Linux I2C driver for fast
4886 mode (400kHZ). This environment variable is used in
4887 initialization code. So, for changes to be effective
4888 it must be saved and board must be reset.
4890 initrd_high - restrict positioning of initrd images:
4891 If this variable is not set, initrd images will be
4892 copied to the highest possible address in RAM; this
4893 is usually what you want since it allows for
4894 maximum initrd size. If for some reason you want to
4895 make sure that the initrd image is loaded below the
4896 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
4897 variable to a value of "no" or "off" or "0".
4898 Alternatively, you can set it to a maximum upper
4899 address to use (U-Boot will still check that it
4900 does not overwrite the U-Boot stack and data).
4902 For instance, when you have a system with 16 MB
4903 RAM, and want to reserve 4 MB from use by Linux,
4904 you can do this by adding "mem=12M" to the value of
4905 the "bootargs" variable. However, now you must make
4906 sure that the initrd image is placed in the first
4907 12 MB as well - this can be done with
4909 setenv initrd_high 00c00000
4911 If you set initrd_high to 0xFFFFFFFF, this is an
4912 indication to U-Boot that all addresses are legal
4913 for the Linux kernel, including addresses in flash
4914 memory. In this case U-Boot will NOT COPY the
4915 ramdisk at all. This may be useful to reduce the
4916 boot time on your system, but requires that this
4917 feature is supported by your Linux kernel.
4919 ipaddr - IP address; needed for tftpboot command
4921 loadaddr - Default load address for commands like "bootp",
4922 "rarpboot", "tftpboot", "loadb" or "diskboot"
4924 loads_echo - see CONFIG_LOADS_ECHO
4926 serverip - TFTP server IP address; needed for tftpboot command
4928 bootretry - see CONFIG_BOOT_RETRY_TIME
4930 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
4932 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
4934 ethprime - controls which interface is used first.
4936 ethact - controls which interface is currently active.
4937 For example you can do the following
4939 => setenv ethact FEC
4940 => ping 192.168.0.1 # traffic sent on FEC
4941 => setenv ethact SCC
4942 => ping 10.0.0.1 # traffic sent on SCC
4944 ethrotate - When set to "no" U-Boot does not go through all
4945 available network interfaces.
4946 It just stays at the currently selected interface.
4948 netretry - When set to "no" each network operation will
4949 either succeed or fail without retrying.
4950 When set to "once" the network operation will
4951 fail when all the available network interfaces
4952 are tried once without success.
4953 Useful on scripts which control the retry operation
4956 npe_ucode - set load address for the NPE microcode
4958 silent_linux - If set then Linux will be told to boot silently, by
4959 changing the console to be empty. If "yes" it will be
4960 made silent. If "no" it will not be made silent. If
4961 unset, then it will be made silent if the U-Boot console
4964 tftpsrcp - If this is set, the value is used for TFTP's
4967 tftpdstp - If this is set, the value is used for TFTP's UDP
4968 destination port instead of the Well Know Port 69.
4970 tftpblocksize - Block size to use for TFTP transfers; if not set,
4971 we use the TFTP server's default block size
4973 tftptimeout - Retransmission timeout for TFTP packets (in milli-
4974 seconds, minimum value is 1000 = 1 second). Defines
4975 when a packet is considered to be lost so it has to
4976 be retransmitted. The default is 5000 = 5 seconds.
4977 Lowering this value may make downloads succeed
4978 faster in networks with high packet loss rates or
4979 with unreliable TFTP servers.
4981 tftptimeoutcountmax - maximum count of TFTP timeouts (no
4982 unit, minimum value = 0). Defines how many timeouts
4983 can happen during a single file transfer before that
4984 transfer is aborted. The default is 10, and 0 means
4985 'no timeouts allowed'. Increasing this value may help
4986 downloads succeed with high packet loss rates, or with
4987 unreliable TFTP servers or client hardware.
4989 vlan - When set to a value < 4095 the traffic over
4990 Ethernet is encapsulated/received over 802.1q
4993 bootpretryperiod - Period during which BOOTP/DHCP sends retries.
4994 Unsigned value, in milliseconds. If not set, the period will
4995 be either the default (28000), or a value based on
4996 CONFIG_NET_RETRY_COUNT, if defined. This value has
4997 precedence over the valu based on CONFIG_NET_RETRY_COUNT.
4999 The following image location variables contain the location of images
5000 used in booting. The "Image" column gives the role of the image and is
5001 not an environment variable name. The other columns are environment
5002 variable names. "File Name" gives the name of the file on a TFTP
5003 server, "RAM Address" gives the location in RAM the image will be
5004 loaded to, and "Flash Location" gives the image's address in NOR
5005 flash or offset in NAND flash.
5007 *Note* - these variables don't have to be defined for all boards, some
5008 boards currently use other variables for these purposes, and some
5009 boards use these variables for other purposes.
5011 Image File Name RAM Address Flash Location
5012 ----- --------- ----------- --------------
5013 u-boot u-boot u-boot_addr_r u-boot_addr
5014 Linux kernel bootfile kernel_addr_r kernel_addr
5015 device tree blob fdtfile fdt_addr_r fdt_addr
5016 ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
5018 The following environment variables may be used and automatically
5019 updated by the network boot commands ("bootp" and "rarpboot"),
5020 depending the information provided by your boot server:
5022 bootfile - see above
5023 dnsip - IP address of your Domain Name Server
5024 dnsip2 - IP address of your secondary Domain Name Server
5025 gatewayip - IP address of the Gateway (Router) to use
5026 hostname - Target hostname
5028 netmask - Subnet Mask
5029 rootpath - Pathname of the root filesystem on the NFS server
5030 serverip - see above
5033 There are two special Environment Variables:
5035 serial# - contains hardware identification information such
5036 as type string and/or serial number
5037 ethaddr - Ethernet address
5039 These variables can be set only once (usually during manufacturing of
5040 the board). U-Boot refuses to delete or overwrite these variables
5041 once they have been set once.
5044 Further special Environment Variables:
5046 ver - Contains the U-Boot version string as printed
5047 with the "version" command. This variable is
5048 readonly (see CONFIG_VERSION_VARIABLE).
5051 Please note that changes to some configuration parameters may take
5052 only effect after the next boot (yes, that's just like Windoze :-).
5055 Callback functions for environment variables:
5056 ---------------------------------------------
5058 For some environment variables, the behavior of u-boot needs to change
5059 when their values are changed. This functionality allows functions to
5060 be associated with arbitrary variables. On creation, overwrite, or
5061 deletion, the callback will provide the opportunity for some side
5062 effect to happen or for the change to be rejected.
5064 The callbacks are named and associated with a function using the
5065 U_BOOT_ENV_CALLBACK macro in your board or driver code.
5067 These callbacks are associated with variables in one of two ways. The
5068 static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC
5069 in the board configuration to a string that defines a list of
5070 associations. The list must be in the following format:
5072 entry = variable_name[:callback_name]
5075 If the callback name is not specified, then the callback is deleted.
5076 Spaces are also allowed anywhere in the list.
5078 Callbacks can also be associated by defining the ".callbacks" variable
5079 with the same list format above. Any association in ".callbacks" will
5080 override any association in the static list. You can define
5081 CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the
5082 ".callbacks" environment variable in the default or embedded environment.
5084 If CONFIG_REGEX is defined, the variable_name above is evaluated as a
5085 regular expression. This allows multiple variables to be connected to
5086 the same callback without explicitly listing them all out.
5089 Command Line Parsing:
5090 =====================
5092 There are two different command line parsers available with U-Boot:
5093 the old "simple" one, and the much more powerful "hush" shell:
5095 Old, simple command line parser:
5096 --------------------------------
5098 - supports environment variables (through setenv / saveenv commands)
5099 - several commands on one line, separated by ';'
5100 - variable substitution using "... ${name} ..." syntax
5101 - special characters ('$', ';') can be escaped by prefixing with '\',
5103 setenv bootcmd bootm \${address}
5104 - You can also escape text by enclosing in single apostrophes, for example:
5105 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
5110 - similar to Bourne shell, with control structures like
5111 if...then...else...fi, for...do...done; while...do...done,
5112 until...do...done, ...
5113 - supports environment ("global") variables (through setenv / saveenv
5114 commands) and local shell variables (through standard shell syntax
5115 "name=value"); only environment variables can be used with "run"
5121 (1) If a command line (or an environment variable executed by a "run"
5122 command) contains several commands separated by semicolon, and
5123 one of these commands fails, then the remaining commands will be
5126 (2) If you execute several variables with one call to run (i. e.
5127 calling run with a list of variables as arguments), any failing
5128 command will cause "run" to terminate, i. e. the remaining
5129 variables are not executed.
5131 Note for Redundant Ethernet Interfaces:
5132 =======================================
5134 Some boards come with redundant Ethernet interfaces; U-Boot supports
5135 such configurations and is capable of automatic selection of a
5136 "working" interface when needed. MAC assignment works as follows:
5138 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
5139 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
5140 "eth1addr" (=>eth1), "eth2addr", ...
5142 If the network interface stores some valid MAC address (for instance
5143 in SROM), this is used as default address if there is NO correspon-
5144 ding setting in the environment; if the corresponding environment
5145 variable is set, this overrides the settings in the card; that means:
5147 o If the SROM has a valid MAC address, and there is no address in the
5148 environment, the SROM's address is used.
5150 o If there is no valid address in the SROM, and a definition in the
5151 environment exists, then the value from the environment variable is
5154 o If both the SROM and the environment contain a MAC address, and
5155 both addresses are the same, this MAC address is used.
5157 o If both the SROM and the environment contain a MAC address, and the
5158 addresses differ, the value from the environment is used and a
5161 o If neither SROM nor the environment contain a MAC address, an error
5162 is raised. If CONFIG_NET_RANDOM_ETHADDR is defined, then in this case
5163 a random, locally-assigned MAC is used.
5165 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
5166 will be programmed into hardware as part of the initialization process. This
5167 may be skipped by setting the appropriate 'ethmacskip' environment variable.
5168 The naming convention is as follows:
5169 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
5174 U-Boot is capable of booting (and performing other auxiliary operations on)
5175 images in two formats:
5177 New uImage format (FIT)
5178 -----------------------
5180 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
5181 to Flattened Device Tree). It allows the use of images with multiple
5182 components (several kernels, ramdisks, etc.), with contents protected by
5183 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
5189 Old image format is based on binary files which can be basically anything,
5190 preceded by a special header; see the definitions in include/image.h for
5191 details; basically, the header defines the following image properties:
5193 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
5194 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
5195 LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
5196 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
5198 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
5199 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
5200 Currently supported: ARM, AVR32, Intel x86, MIPS, NDS32, Nios II, PowerPC).
5201 * Compression Type (uncompressed, gzip, bzip2)
5207 The header is marked by a special Magic Number, and both the header
5208 and the data portions of the image are secured against corruption by
5215 Although U-Boot should support any OS or standalone application
5216 easily, the main focus has always been on Linux during the design of
5219 U-Boot includes many features that so far have been part of some
5220 special "boot loader" code within the Linux kernel. Also, any
5221 "initrd" images to be used are no longer part of one big Linux image;
5222 instead, kernel and "initrd" are separate images. This implementation
5223 serves several purposes:
5225 - the same features can be used for other OS or standalone
5226 applications (for instance: using compressed images to reduce the
5227 Flash memory footprint)
5229 - it becomes much easier to port new Linux kernel versions because
5230 lots of low-level, hardware dependent stuff are done by U-Boot
5232 - the same Linux kernel image can now be used with different "initrd"
5233 images; of course this also means that different kernel images can
5234 be run with the same "initrd". This makes testing easier (you don't
5235 have to build a new "zImage.initrd" Linux image when you just
5236 change a file in your "initrd"). Also, a field-upgrade of the
5237 software is easier now.
5243 Porting Linux to U-Boot based systems:
5244 ---------------------------------------
5246 U-Boot cannot save you from doing all the necessary modifications to
5247 configure the Linux device drivers for use with your target hardware
5248 (no, we don't intend to provide a full virtual machine interface to
5251 But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot).
5253 Just make sure your machine specific header file (for instance
5254 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
5255 Information structure as we define in include/asm-<arch>/u-boot.h,
5256 and make sure that your definition of IMAP_ADDR uses the same value
5257 as your U-Boot configuration in CONFIG_SYS_IMMR.
5259 Note that U-Boot now has a driver model, a unified model for drivers.
5260 If you are adding a new driver, plumb it into driver model. If there
5261 is no uclass available, you are encouraged to create one. See
5265 Configuring the Linux kernel:
5266 -----------------------------
5268 No specific requirements for U-Boot. Make sure you have some root
5269 device (initial ramdisk, NFS) for your target system.
5272 Building a Linux Image:
5273 -----------------------
5275 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
5276 not used. If you use recent kernel source, a new build target
5277 "uImage" will exist which automatically builds an image usable by
5278 U-Boot. Most older kernels also have support for a "pImage" target,
5279 which was introduced for our predecessor project PPCBoot and uses a
5280 100% compatible format.
5284 make TQM850L_defconfig
5289 The "uImage" build target uses a special tool (in 'tools/mkimage') to
5290 encapsulate a compressed Linux kernel image with header information,
5291 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
5293 * build a standard "vmlinux" kernel image (in ELF binary format):
5295 * convert the kernel into a raw binary image:
5297 ${CROSS_COMPILE}-objcopy -O binary \
5298 -R .note -R .comment \
5299 -S vmlinux linux.bin
5301 * compress the binary image:
5305 * package compressed binary image for U-Boot:
5307 mkimage -A ppc -O linux -T kernel -C gzip \
5308 -a 0 -e 0 -n "Linux Kernel Image" \
5309 -d linux.bin.gz uImage
5312 The "mkimage" tool can also be used to create ramdisk images for use
5313 with U-Boot, either separated from the Linux kernel image, or
5314 combined into one file. "mkimage" encapsulates the images with a 64
5315 byte header containing information about target architecture,
5316 operating system, image type, compression method, entry points, time
5317 stamp, CRC32 checksums, etc.
5319 "mkimage" can be called in two ways: to verify existing images and
5320 print the header information, or to build new images.
5322 In the first form (with "-l" option) mkimage lists the information
5323 contained in the header of an existing U-Boot image; this includes
5324 checksum verification:
5326 tools/mkimage -l image
5327 -l ==> list image header information
5329 The second form (with "-d" option) is used to build a U-Boot image
5330 from a "data file" which is used as image payload:
5332 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
5333 -n name -d data_file image
5334 -A ==> set architecture to 'arch'
5335 -O ==> set operating system to 'os'
5336 -T ==> set image type to 'type'
5337 -C ==> set compression type 'comp'
5338 -a ==> set load address to 'addr' (hex)
5339 -e ==> set entry point to 'ep' (hex)
5340 -n ==> set image name to 'name'
5341 -d ==> use image data from 'datafile'
5343 Right now, all Linux kernels for PowerPC systems use the same load
5344 address (0x00000000), but the entry point address depends on the
5347 - 2.2.x kernels have the entry point at 0x0000000C,
5348 - 2.3.x and later kernels have the entry point at 0x00000000.
5350 So a typical call to build a U-Boot image would read:
5352 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5353 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
5354 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \
5355 > examples/uImage.TQM850L
5356 Image Name: 2.4.4 kernel for TQM850L
5357 Created: Wed Jul 19 02:34:59 2000
5358 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5359 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5360 Load Address: 0x00000000
5361 Entry Point: 0x00000000
5363 To verify the contents of the image (or check for corruption):
5365 -> tools/mkimage -l examples/uImage.TQM850L
5366 Image Name: 2.4.4 kernel for TQM850L
5367 Created: Wed Jul 19 02:34:59 2000
5368 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5369 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
5370 Load Address: 0x00000000
5371 Entry Point: 0x00000000
5373 NOTE: for embedded systems where boot time is critical you can trade
5374 speed for memory and install an UNCOMPRESSED image instead: this
5375 needs more space in Flash, but boots much faster since it does not
5376 need to be uncompressed:
5378 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz
5379 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
5380 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
5381 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \
5382 > examples/uImage.TQM850L-uncompressed
5383 Image Name: 2.4.4 kernel for TQM850L
5384 Created: Wed Jul 19 02:34:59 2000
5385 Image Type: PowerPC Linux Kernel Image (uncompressed)
5386 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
5387 Load Address: 0x00000000
5388 Entry Point: 0x00000000
5391 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
5392 when your kernel is intended to use an initial ramdisk:
5394 -> tools/mkimage -n 'Simple Ramdisk Image' \
5395 > -A ppc -O linux -T ramdisk -C gzip \
5396 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
5397 Image Name: Simple Ramdisk Image
5398 Created: Wed Jan 12 14:01:50 2000
5399 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5400 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
5401 Load Address: 0x00000000
5402 Entry Point: 0x00000000
5404 The "dumpimage" is a tool to disassemble images built by mkimage. Its "-i"
5405 option performs the converse operation of the mkimage's second form (the "-d"
5406 option). Given an image built by mkimage, the dumpimage extracts a "data file"
5409 tools/dumpimage -i image -T type -p position data_file
5410 -i ==> extract from the 'image' a specific 'data_file'
5411 -T ==> set image type to 'type'
5412 -p ==> 'position' (starting at 0) of the 'data_file' inside the 'image'
5415 Installing a Linux Image:
5416 -------------------------
5418 To downloading a U-Boot image over the serial (console) interface,
5419 you must convert the image to S-Record format:
5421 objcopy -I binary -O srec examples/image examples/image.srec
5423 The 'objcopy' does not understand the information in the U-Boot
5424 image header, so the resulting S-Record file will be relative to
5425 address 0x00000000. To load it to a given address, you need to
5426 specify the target address as 'offset' parameter with the 'loads'
5429 Example: install the image to address 0x40100000 (which on the
5430 TQM8xxL is in the first Flash bank):
5432 => erase 40100000 401FFFFF
5438 ## Ready for S-Record download ...
5439 ~>examples/image.srec
5440 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
5442 15989 15990 15991 15992
5443 [file transfer complete]
5445 ## Start Addr = 0x00000000
5448 You can check the success of the download using the 'iminfo' command;
5449 this includes a checksum verification so you can be sure no data
5450 corruption happened:
5454 ## Checking Image at 40100000 ...
5455 Image Name: 2.2.13 for initrd on TQM850L
5456 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5457 Data Size: 335725 Bytes = 327 kB = 0 MB
5458 Load Address: 00000000
5459 Entry Point: 0000000c
5460 Verifying Checksum ... OK
5466 The "bootm" command is used to boot an application that is stored in
5467 memory (RAM or Flash). In case of a Linux kernel image, the contents
5468 of the "bootargs" environment variable is passed to the kernel as
5469 parameters. You can check and modify this variable using the
5470 "printenv" and "setenv" commands:
5473 => printenv bootargs
5474 bootargs=root=/dev/ram
5476 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5478 => printenv bootargs
5479 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5482 ## Booting Linux kernel at 40020000 ...
5483 Image Name: 2.2.13 for NFS on TQM850L
5484 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5485 Data Size: 381681 Bytes = 372 kB = 0 MB
5486 Load Address: 00000000
5487 Entry Point: 0000000c
5488 Verifying Checksum ... OK
5489 Uncompressing Kernel Image ... OK
5490 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
5491 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
5492 time_init: decrementer frequency = 187500000/60
5493 Calibrating delay loop... 49.77 BogoMIPS
5494 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
5497 If you want to boot a Linux kernel with initial RAM disk, you pass
5498 the memory addresses of both the kernel and the initrd image (PPBCOOT
5499 format!) to the "bootm" command:
5501 => imi 40100000 40200000
5503 ## Checking Image at 40100000 ...
5504 Image Name: 2.2.13 for initrd on TQM850L
5505 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5506 Data Size: 335725 Bytes = 327 kB = 0 MB
5507 Load Address: 00000000
5508 Entry Point: 0000000c
5509 Verifying Checksum ... OK
5511 ## Checking Image at 40200000 ...
5512 Image Name: Simple Ramdisk Image
5513 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5514 Data Size: 566530 Bytes = 553 kB = 0 MB
5515 Load Address: 00000000
5516 Entry Point: 00000000
5517 Verifying Checksum ... OK
5519 => bootm 40100000 40200000
5520 ## Booting Linux kernel at 40100000 ...
5521 Image Name: 2.2.13 for initrd on TQM850L
5522 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5523 Data Size: 335725 Bytes = 327 kB = 0 MB
5524 Load Address: 00000000
5525 Entry Point: 0000000c
5526 Verifying Checksum ... OK
5527 Uncompressing Kernel Image ... OK
5528 ## Loading RAMDisk Image at 40200000 ...
5529 Image Name: Simple Ramdisk Image
5530 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
5531 Data Size: 566530 Bytes = 553 kB = 0 MB
5532 Load Address: 00000000
5533 Entry Point: 00000000
5534 Verifying Checksum ... OK
5535 Loading Ramdisk ... OK
5536 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
5537 Boot arguments: root=/dev/ram
5538 time_init: decrementer frequency = 187500000/60
5539 Calibrating delay loop... 49.77 BogoMIPS
5541 RAMDISK: Compressed image found at block 0
5542 VFS: Mounted root (ext2 filesystem).
5546 Boot Linux and pass a flat device tree:
5549 First, U-Boot must be compiled with the appropriate defines. See the section
5550 titled "Linux Kernel Interface" above for a more in depth explanation. The
5551 following is an example of how to start a kernel and pass an updated
5557 oft=oftrees/mpc8540ads.dtb
5558 => tftp $oftaddr $oft
5559 Speed: 1000, full duplex
5561 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
5562 Filename 'oftrees/mpc8540ads.dtb'.
5563 Load address: 0x300000
5566 Bytes transferred = 4106 (100a hex)
5567 => tftp $loadaddr $bootfile
5568 Speed: 1000, full duplex
5570 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
5572 Load address: 0x200000
5573 Loading:############
5575 Bytes transferred = 1029407 (fb51f hex)
5580 => bootm $loadaddr - $oftaddr
5581 ## Booting image at 00200000 ...
5582 Image Name: Linux-2.6.17-dirty
5583 Image Type: PowerPC Linux Kernel Image (gzip compressed)
5584 Data Size: 1029343 Bytes = 1005.2 kB
5585 Load Address: 00000000
5586 Entry Point: 00000000
5587 Verifying Checksum ... OK
5588 Uncompressing Kernel Image ... OK
5589 Booting using flat device tree at 0x300000
5590 Using MPC85xx ADS machine description
5591 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
5595 More About U-Boot Image Types:
5596 ------------------------------
5598 U-Boot supports the following image types:
5600 "Standalone Programs" are directly runnable in the environment
5601 provided by U-Boot; it is expected that (if they behave
5602 well) you can continue to work in U-Boot after return from
5603 the Standalone Program.
5604 "OS Kernel Images" are usually images of some Embedded OS which
5605 will take over control completely. Usually these programs
5606 will install their own set of exception handlers, device
5607 drivers, set up the MMU, etc. - this means, that you cannot
5608 expect to re-enter U-Boot except by resetting the CPU.
5609 "RAMDisk Images" are more or less just data blocks, and their
5610 parameters (address, size) are passed to an OS kernel that is
5612 "Multi-File Images" contain several images, typically an OS
5613 (Linux) kernel image and one or more data images like
5614 RAMDisks. This construct is useful for instance when you want
5615 to boot over the network using BOOTP etc., where the boot
5616 server provides just a single image file, but you want to get
5617 for instance an OS kernel and a RAMDisk image.
5619 "Multi-File Images" start with a list of image sizes, each
5620 image size (in bytes) specified by an "uint32_t" in network
5621 byte order. This list is terminated by an "(uint32_t)0".
5622 Immediately after the terminating 0 follow the images, one by
5623 one, all aligned on "uint32_t" boundaries (size rounded up to
5624 a multiple of 4 bytes).
5626 "Firmware Images" are binary images containing firmware (like
5627 U-Boot or FPGA images) which usually will be programmed to
5630 "Script files" are command sequences that will be executed by
5631 U-Boot's command interpreter; this feature is especially
5632 useful when you configure U-Boot to use a real shell (hush)
5633 as command interpreter.
5635 Booting the Linux zImage:
5636 -------------------------
5638 On some platforms, it's possible to boot Linux zImage. This is done
5639 using the "bootz" command. The syntax of "bootz" command is the same
5640 as the syntax of "bootm" command.
5642 Note, defining the CONFIG_SUPPORT_RAW_INITRD allows user to supply
5643 kernel with raw initrd images. The syntax is slightly different, the
5644 address of the initrd must be augmented by it's size, in the following
5645 format: "<initrd addres>:<initrd size>".
5651 One of the features of U-Boot is that you can dynamically load and
5652 run "standalone" applications, which can use some resources of
5653 U-Boot like console I/O functions or interrupt services.
5655 Two simple examples are included with the sources:
5660 'examples/hello_world.c' contains a small "Hello World" Demo
5661 application; it is automatically compiled when you build U-Boot.
5662 It's configured to run at address 0x00040004, so you can play with it
5666 ## Ready for S-Record download ...
5667 ~>examples/hello_world.srec
5668 1 2 3 4 5 6 7 8 9 10 11 ...
5669 [file transfer complete]
5671 ## Start Addr = 0x00040004
5673 => go 40004 Hello World! This is a test.
5674 ## Starting application at 0x00040004 ...
5685 Hit any key to exit ...
5687 ## Application terminated, rc = 0x0
5689 Another example, which demonstrates how to register a CPM interrupt
5690 handler with the U-Boot code, can be found in 'examples/timer.c'.
5691 Here, a CPM timer is set up to generate an interrupt every second.
5692 The interrupt service routine is trivial, just printing a '.'
5693 character, but this is just a demo program. The application can be
5694 controlled by the following keys:
5696 ? - print current values og the CPM Timer registers
5697 b - enable interrupts and start timer
5698 e - stop timer and disable interrupts
5699 q - quit application
5702 ## Ready for S-Record download ...
5703 ~>examples/timer.srec
5704 1 2 3 4 5 6 7 8 9 10 11 ...
5705 [file transfer complete]
5707 ## Start Addr = 0x00040004
5710 ## Starting application at 0x00040004 ...
5713 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
5716 [q, b, e, ?] Set interval 1000000 us
5719 [q, b, e, ?] ........
5720 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
5723 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
5726 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
5729 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
5731 [q, b, e, ?] ...Stopping timer
5733 [q, b, e, ?] ## Application terminated, rc = 0x0
5739 Over time, many people have reported problems when trying to use the
5740 "minicom" terminal emulation program for serial download. I (wd)
5741 consider minicom to be broken, and recommend not to use it. Under
5742 Unix, I recommend to use C-Kermit for general purpose use (and
5743 especially for kermit binary protocol download ("loadb" command), and
5744 use "cu" for S-Record download ("loads" command). See
5745 http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3.
5746 for help with kermit.
5749 Nevertheless, if you absolutely want to use it try adding this
5750 configuration to your "File transfer protocols" section:
5752 Name Program Name U/D FullScr IO-Red. Multi
5753 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
5754 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
5760 Starting at version 0.9.2, U-Boot supports NetBSD both as host
5761 (build U-Boot) and target system (boots NetBSD/mpc8xx).
5763 Building requires a cross environment; it is known to work on
5764 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
5765 need gmake since the Makefiles are not compatible with BSD make).
5766 Note that the cross-powerpc package does not install include files;
5767 attempting to build U-Boot will fail because <machine/ansi.h> is
5768 missing. This file has to be installed and patched manually:
5770 # cd /usr/pkg/cross/powerpc-netbsd/include
5772 # ln -s powerpc machine
5773 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
5774 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
5776 Native builds *don't* work due to incompatibilities between native
5777 and U-Boot include files.
5779 Booting assumes that (the first part of) the image booted is a
5780 stage-2 loader which in turn loads and then invokes the kernel
5781 proper. Loader sources will eventually appear in the NetBSD source
5782 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
5783 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
5786 Implementation Internals:
5787 =========================
5789 The following is not intended to be a complete description of every
5790 implementation detail. However, it should help to understand the
5791 inner workings of U-Boot and make it easier to port it to custom
5795 Initial Stack, Global Data:
5796 ---------------------------
5798 The implementation of U-Boot is complicated by the fact that U-Boot
5799 starts running out of ROM (flash memory), usually without access to
5800 system RAM (because the memory controller is not initialized yet).
5801 This means that we don't have writable Data or BSS segments, and BSS
5802 is not initialized as zero. To be able to get a C environment working
5803 at all, we have to allocate at least a minimal stack. Implementation
5804 options for this are defined and restricted by the CPU used: Some CPU
5805 models provide on-chip memory (like the IMMR area on MPC8xx and
5806 MPC826x processors), on others (parts of) the data cache can be
5807 locked as (mis-) used as memory, etc.
5809 Chris Hallinan posted a good summary of these issues to the
5810 U-Boot mailing list:
5812 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
5813 From: "Chris Hallinan" <clh@net1plus.com>
5814 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
5817 Correct me if I'm wrong, folks, but the way I understand it
5818 is this: Using DCACHE as initial RAM for Stack, etc, does not
5819 require any physical RAM backing up the cache. The cleverness
5820 is that the cache is being used as a temporary supply of
5821 necessary storage before the SDRAM controller is setup. It's
5822 beyond the scope of this list to explain the details, but you
5823 can see how this works by studying the cache architecture and
5824 operation in the architecture and processor-specific manuals.
5826 OCM is On Chip Memory, which I believe the 405GP has 4K. It
5827 is another option for the system designer to use as an
5828 initial stack/RAM area prior to SDRAM being available. Either
5829 option should work for you. Using CS 4 should be fine if your
5830 board designers haven't used it for something that would
5831 cause you grief during the initial boot! It is frequently not
5834 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere
5835 with your processor/board/system design. The default value
5836 you will find in any recent u-boot distribution in
5837 walnut.h should work for you. I'd set it to a value larger
5838 than your SDRAM module. If you have a 64MB SDRAM module, set
5839 it above 400_0000. Just make sure your board has no resources
5840 that are supposed to respond to that address! That code in
5841 start.S has been around a while and should work as is when
5842 you get the config right.
5847 It is essential to remember this, since it has some impact on the C
5848 code for the initialization procedures:
5850 * Initialized global data (data segment) is read-only. Do not attempt
5853 * Do not use any uninitialized global data (or implicitly initialized
5854 as zero data - BSS segment) at all - this is undefined, initiali-
5855 zation is performed later (when relocating to RAM).
5857 * Stack space is very limited. Avoid big data buffers or things like
5860 Having only the stack as writable memory limits means we cannot use
5861 normal global data to share information between the code. But it
5862 turned out that the implementation of U-Boot can be greatly
5863 simplified by making a global data structure (gd_t) available to all
5864 functions. We could pass a pointer to this data as argument to _all_
5865 functions, but this would bloat the code. Instead we use a feature of
5866 the GCC compiler (Global Register Variables) to share the data: we
5867 place a pointer (gd) to the global data into a register which we
5868 reserve for this purpose.
5870 When choosing a register for such a purpose we are restricted by the
5871 relevant (E)ABI specifications for the current architecture, and by
5872 GCC's implementation.
5874 For PowerPC, the following registers have specific use:
5876 R2: reserved for system use
5877 R3-R4: parameter passing and return values
5878 R5-R10: parameter passing
5879 R13: small data area pointer
5883 (U-Boot also uses R12 as internal GOT pointer. r12
5884 is a volatile register so r12 needs to be reset when
5885 going back and forth between asm and C)
5887 ==> U-Boot will use R2 to hold a pointer to the global data
5889 Note: on PPC, we could use a static initializer (since the
5890 address of the global data structure is known at compile time),
5891 but it turned out that reserving a register results in somewhat
5892 smaller code - although the code savings are not that big (on
5893 average for all boards 752 bytes for the whole U-Boot image,
5894 624 text + 127 data).
5896 On ARM, the following registers are used:
5898 R0: function argument word/integer result
5899 R1-R3: function argument word
5900 R9: platform specific
5901 R10: stack limit (used only if stack checking is enabled)
5902 R11: argument (frame) pointer
5903 R12: temporary workspace
5906 R15: program counter
5908 ==> U-Boot will use R9 to hold a pointer to the global data
5910 Note: on ARM, only R_ARM_RELATIVE relocations are supported.
5912 On Nios II, the ABI is documented here:
5913 http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
5915 ==> U-Boot will use gp to hold a pointer to the global data
5917 Note: on Nios II, we give "-G0" option to gcc and don't use gp
5918 to access small data sections, so gp is free.
5920 On NDS32, the following registers are used:
5922 R0-R1: argument/return
5924 R15: temporary register for assembler
5925 R16: trampoline register
5926 R28: frame pointer (FP)
5927 R29: global pointer (GP)
5928 R30: link register (LP)
5929 R31: stack pointer (SP)
5930 PC: program counter (PC)
5932 ==> U-Boot will use R10 to hold a pointer to the global data
5934 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
5935 or current versions of GCC may "optimize" the code too much.
5940 U-Boot runs in system state and uses physical addresses, i.e. the
5941 MMU is not used either for address mapping nor for memory protection.
5943 The available memory is mapped to fixed addresses using the memory
5944 controller. In this process, a contiguous block is formed for each
5945 memory type (Flash, SDRAM, SRAM), even when it consists of several
5946 physical memory banks.
5948 U-Boot is installed in the first 128 kB of the first Flash bank (on
5949 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
5950 booting and sizing and initializing DRAM, the code relocates itself
5951 to the upper end of DRAM. Immediately below the U-Boot code some
5952 memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
5953 configuration setting]. Below that, a structure with global Board
5954 Info data is placed, followed by the stack (growing downward).
5956 Additionally, some exception handler code is copied to the low 8 kB
5957 of DRAM (0x00000000 ... 0x00001FFF).
5959 So a typical memory configuration with 16 MB of DRAM could look like
5962 0x0000 0000 Exception Vector code
5965 0x0000 2000 Free for Application Use
5971 0x00FB FF20 Monitor Stack (Growing downward)
5972 0x00FB FFAC Board Info Data and permanent copy of global data
5973 0x00FC 0000 Malloc Arena
5976 0x00FE 0000 RAM Copy of Monitor Code
5977 ... eventually: LCD or video framebuffer
5978 ... eventually: pRAM (Protected RAM - unchanged by reset)
5979 0x00FF FFFF [End of RAM]
5982 System Initialization:
5983 ----------------------
5985 In the reset configuration, U-Boot starts at the reset entry point
5986 (on most PowerPC systems at address 0x00000100). Because of the reset
5987 configuration for CS0# this is a mirror of the on board Flash memory.
5988 To be able to re-map memory U-Boot then jumps to its link address.
5989 To be able to implement the initialization code in C, a (small!)
5990 initial stack is set up in the internal Dual Ported RAM (in case CPUs
5991 which provide such a feature like MPC8xx or MPC8260), or in a locked
5992 part of the data cache. After that, U-Boot initializes the CPU core,
5993 the caches and the SIU.
5995 Next, all (potentially) available memory banks are mapped using a
5996 preliminary mapping. For example, we put them on 512 MB boundaries
5997 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
5998 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
5999 programmed for SDRAM access. Using the temporary configuration, a
6000 simple memory test is run that determines the size of the SDRAM
6003 When there is more than one SDRAM bank, and the banks are of
6004 different size, the largest is mapped first. For equal size, the first
6005 bank (CS2#) is mapped first. The first mapping is always for address
6006 0x00000000, with any additional banks following immediately to create
6007 contiguous memory starting from 0.
6009 Then, the monitor installs itself at the upper end of the SDRAM area
6010 and allocates memory for use by malloc() and for the global Board
6011 Info data; also, the exception vector code is copied to the low RAM
6012 pages, and the final stack is set up.
6014 Only after this relocation will you have a "normal" C environment;
6015 until that you are restricted in several ways, mostly because you are
6016 running from ROM, and because the code will have to be relocated to a
6020 U-Boot Porting Guide:
6021 ----------------------
6023 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
6027 int main(int argc, char *argv[])
6029 sighandler_t no_more_time;
6031 signal(SIGALRM, no_more_time);
6032 alarm(PROJECT_DEADLINE - toSec (3 * WEEK));
6034 if (available_money > available_manpower) {
6035 Pay consultant to port U-Boot;
6039 Download latest U-Boot source;
6041 Subscribe to u-boot mailing list;
6044 email("Hi, I am new to U-Boot, how do I get started?");
6047 Read the README file in the top level directory;
6048 Read http://www.denx.de/twiki/bin/view/DULG/Manual;
6049 Read applicable doc/*.README;
6050 Read the source, Luke;
6051 /* find . -name "*.[chS]" | xargs grep -i <keyword> */
6054 if (available_money > toLocalCurrency ($2500))
6057 Add a lot of aggravation and time;
6059 if (a similar board exists) { /* hopefully... */
6060 cp -a board/<similar> board/<myboard>
6061 cp include/configs/<similar>.h include/configs/<myboard>.h
6063 Create your own board support subdirectory;
6064 Create your own board include/configs/<myboard>.h file;
6066 Edit new board/<myboard> files
6067 Edit new include/configs/<myboard>.h
6072 Add / modify source code;
6076 email("Hi, I am having problems...");
6078 Send patch file to the U-Boot email list;
6079 if (reasonable critiques)
6080 Incorporate improvements from email list code review;
6082 Defend code as written;
6088 void no_more_time (int sig)
6097 All contributions to U-Boot should conform to the Linux kernel
6098 coding style; see the file "Documentation/CodingStyle" and the script
6099 "scripts/Lindent" in your Linux kernel source directory.
6101 Source files originating from a different project (for example the
6102 MTD subsystem) are generally exempt from these guidelines and are not
6103 reformatted to ease subsequent migration to newer versions of those
6106 Please note that U-Boot is implemented in C (and to some small parts in
6107 Assembler); no C++ is used, so please do not use C++ style comments (//)
6110 Please also stick to the following formatting rules:
6111 - remove any trailing white space
6112 - use TAB characters for indentation and vertical alignment, not spaces
6113 - make sure NOT to use DOS '\r\n' line feeds
6114 - do not add more than 2 consecutive empty lines to source files
6115 - do not add trailing empty lines to source files
6117 Submissions which do not conform to the standards may be returned
6118 with a request to reformat the changes.
6124 Since the number of patches for U-Boot is growing, we need to
6125 establish some rules. Submissions which do not conform to these rules
6126 may be rejected, even when they contain important and valuable stuff.
6128 Please see http://www.denx.de/wiki/U-Boot/Patches for details.
6130 Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>;
6131 see http://lists.denx.de/mailman/listinfo/u-boot
6133 When you send a patch, please include the following information with
6136 * For bug fixes: a description of the bug and how your patch fixes
6137 this bug. Please try to include a way of demonstrating that the
6138 patch actually fixes something.
6140 * For new features: a description of the feature and your
6143 * A CHANGELOG entry as plaintext (separate from the patch)
6145 * For major contributions, add a MAINTAINERS file with your
6146 information and associated file and directory references.
6148 * When you add support for a new board, don't forget to add a
6149 maintainer e-mail address to the boards.cfg file, too.
6151 * If your patch adds new configuration options, don't forget to
6152 document these in the README file.
6154 * The patch itself. If you are using git (which is *strongly*
6155 recommended) you can easily generate the patch using the
6156 "git format-patch". If you then use "git send-email" to send it to
6157 the U-Boot mailing list, you will avoid most of the common problems
6158 with some other mail clients.
6160 If you cannot use git, use "diff -purN OLD NEW". If your version of
6161 diff does not support these options, then get the latest version of
6164 The current directory when running this command shall be the parent
6165 directory of the U-Boot source tree (i. e. please make sure that
6166 your patch includes sufficient directory information for the
6169 We prefer patches as plain text. MIME attachments are discouraged,
6170 and compressed attachments must not be used.
6172 * If one logical set of modifications affects or creates several
6173 files, all these changes shall be submitted in a SINGLE patch file.
6175 * Changesets that contain different, unrelated modifications shall be
6176 submitted as SEPARATE patches, one patch per changeset.
6181 * Before sending the patch, run the buildman script on your patched
6182 source tree and make sure that no errors or warnings are reported
6183 for any of the boards.
6185 * Keep your modifications to the necessary minimum: A patch
6186 containing several unrelated changes or arbitrary reformats will be
6187 returned with a request to re-formatting / split it.
6189 * If you modify existing code, make sure that your new code does not
6190 add to the memory footprint of the code ;-) Small is beautiful!
6191 When adding new features, these should compile conditionally only
6192 (using #ifdef), and the resulting code with the new feature
6193 disabled must not need more memory than the old code without your
6196 * Remember that there is a size limit of 100 kB per message on the
6197 u-boot mailing list. Bigger patches will be moderated. If they are
6198 reasonable and not too big, they will be acknowledged. But patches
6199 bigger than the size limit should be avoided.