* Provide extended interface to Linux boot loader
* S-Record download
* network boot
- * PCMCIA / CompactFlash / ATA disk / SCSI ... boot
+ * ATA disk / SCSI ... boot
- create ARMBoot project (http://sourceforge.net/projects/armboot)
- add other CPU families (starting with ARM)
- create U-Boot project (http://sourceforge.net/projects/u-boot)
specific to be undertaken on a native platform. The sandbox is also used to
run some of U-Boot's tests.
-See board/sandbox/README.sandbox for more details.
+See doc/arch/index.rst for more details.
Board Initialisation Flow:
- preloader_console_init() can be called here in extremis
- should set up SDRAM, and anything needed to make the UART work
- these is no need to clear BSS, it will be done by crt0.S
+ - for specific scenarios on certain architectures an early BSS *can*
+ be made available (via CONFIG_SPL_EARLY_BSS by moving the clearing
+ of BSS prior to entering board_init_f()) but doing so is discouraged.
+ Instead it is strongly recommended to architect any code changes
+ or additions such to not depend on the availability of BSS during
+ board_init_f() as indicated in other sections of this README to
+ maintain compatibility and consistency across the entire code base.
- must return normally from this function (don't call board_init_r()
directly)
PBI commands can be used to configure SoC before it starts the execution.
Please refer doc/README.pblimage for more details
- CONFIG_SPL_FSL_PBL
- It adds a target to create boot binary having SPL binary in PBI format
- concatenated with u-boot binary.
-
CONFIG_SYS_FSL_DDR_BE
Defines the DDR controller register space as Big Endian
pointer. This is needed for the temporary stack before
relocation.
- CONFIG_SYS_MIPS_CACHE_MODE
-
- Cache operation mode for the MIPS CPU.
- See also arch/mips/include/asm/mipsregs.h.
- Possible values are:
- CONF_CM_CACHABLE_NO_WA
- CONF_CM_CACHABLE_WA
- CONF_CM_UNCACHED
- CONF_CM_CACHABLE_NONCOHERENT
- CONF_CM_CACHABLE_CE
- CONF_CM_CACHABLE_COW
- CONF_CM_CACHABLE_CUW
- CONF_CM_CACHABLE_ACCELERATED
-
- CONFIG_SYS_XWAY_EBU_BOOTCFG
-
- Special option for Lantiq XWAY SoCs for booting from NOR flash.
- See also arch/mips/cpu/mips32/start.S.
-
CONFIG_XWAY_SWAP_BYTES
Enable compilation of tools/xway-swap-bytes needed for Lantiq
the defaults discussed just above.
- Cache Configuration:
- CONFIG_SYS_ICACHE_OFF - Do not enable instruction cache in U-Boot
- CONFIG_SYS_DCACHE_OFF - Do not enable data cache in U-Boot
CONFIG_SYS_L2CACHE_OFF- Do not enable L2 cache in U-Boot
- Cache Configuration for ARM:
as a convenience, when switching between booting from
RAM and NFS.
-- Pre-Boot Commands:
- CONFIG_PREBOOT
-
- When this option is #defined, the existence of the
- environment variable "preboot" will be checked
- immediately before starting the CONFIG_BOOTDELAY
- countdown and/or running the auto-boot command resp.
- entering interactive mode.
-
- This feature is especially useful when "preboot" is
- automatically generated or modified. For an example
- see the LWMON board specific code: here "preboot" is
- modified when the user holds down a certain
- combination of keys on the (special) keyboard when
- booting the systems
-
- Serial Download Echo Mode:
CONFIG_LOADS_ECHO
If defined to 1, all characters received during a
SoC, then define this variable and provide board
specific code for the "hw_watchdog_reset" function.
- CONFIG_AT91_HW_WDT_TIMEOUT
- specify the timeout in seconds. default 2 seconds.
-
- Real-Time Clock:
When CONFIG_CMD_DATE is selected, the type of the RTC
CONFIG_EFI_PARTITION GPT partition table, common when EFI is the
bootloader. Note 2TB partition limit; see
disk/part_efi.c
- CONFIG_MTD_PARTITIONS Memory Technology Device partition table.
-
- If IDE or SCSI support is enabled (CONFIG_IDE or
CONFIG_SCSI) you must configure support for at
least one non-MTD partition type as well.
Define this to use i/o functions instead of macros
(some hardware wont work with macros)
- CONFIG_DRIVER_TI_EMAC
- Support for davinci emac
-
CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
Define this if you have more then 3 PHYs.
CONFIG_SH_ETHER_CACHE_WRITEBACK
If this option is set, the driver enables cache flush.
-- PWM Support:
- CONFIG_PWM_IMX
- Support for PWM module on the imx6.
-
- TPM Support:
CONFIG_TPM
Support TPM devices.
CONFIG_SH_MMCIF_CLK
Define the clock frequency for MMCIF
- CONFIG_SUPPORT_EMMC_BOOT
- Enable some additional features of the eMMC boot partitions.
-
- USB Device Firmware Update (DFU) class support:
CONFIG_DFU_OVER_USB
This enables the USB portion of the DFU USB class
- CONFIG_DFU_MMC
- This enables support for exposing (e)MMC devices via DFU.
-
CONFIG_DFU_NAND
This enables support for exposing NAND devices via DFU.
forwarded through a router.
(Environment variable "netmask")
-- Multicast TFTP Mode:
- CONFIG_MCAST_TFTP
-
- Defines whether you want to support multicast TFTP as per
- rfc-2090; for example to work with atftp. Lets lots of targets
- tftp down the same boot image concurrently. Note: the Ethernet
- driver in use must provide a function: mcast() to join/leave a
- multicast group.
-
- BOOTP Recovery Mode:
CONFIG_BOOTP_RANDOM_DELAY
- CONFIG_SYS_OMAP24_I2C_SPEED4 speed channel 4
- CONFIG_SYS_OMAP24_I2C_SLAVE4 slave addr channel 4
- - drivers/i2c/zynq_i2c.c
- - activate this driver with CONFIG_SYS_I2C_ZYNQ
- - set CONFIG_SYS_I2C_ZYNQ_SPEED for speed setting
- - set CONFIG_SYS_I2C_ZYNQ_SLAVE for slave addr
-
- drivers/i2c/s3c24x0_i2c.c:
- activate this driver with CONFIG_SYS_I2C_S3C24X0
- This driver adds i2c buses (11 for Exynos5250, Exynos5420
SPI configuration items (port pins to use, etc). For
an example, see include/configs/sacsng.h.
- CONFIG_HARD_SPI
-
- Enables a hardware SPI driver for general-purpose reads
- and writes. As with CONFIG_SOFT_SPI, the board configuration
- must define a list of chip-select function pointers.
- Currently supported on some MPC8xxx processors. For an
- example, see include/configs/mpc8349emds.h.
-
CONFIG_SYS_SPI_MXC_WAIT
Timeout for waiting until spi transfer completed.
default: (CONFIG_SYS_HZ/100) /* 10 ms */
200 ms.
- Configuration Management:
- CONFIG_BUILD_TARGET
-
- Some SoCs need special image types (e.g. U-Boot binary
- with a special header) as build targets. By defining
- CONFIG_BUILD_TARGET in the SoC / board header, this
- special image will be automatically built upon calling
- make / buildman.
CONFIG_IDENT_STRING
this is instead controlled by the value of
/config/load-environment.
-- Serial Flash support
- Usage requires an initial 'sf probe' to define the serial
- flash parameters, followed by read/write/erase/update
- commands.
-
- The following defaults may be provided by the platform
- to handle the common case when only a single serial
- flash is present on the system.
-
- CONFIG_SF_DEFAULT_BUS Bus identifier
- CONFIG_SF_DEFAULT_CS Chip-select
- CONFIG_SF_DEFAULT_MODE (see include/spi.h)
- CONFIG_SF_DEFAULT_SPEED in Hz
-
-
- TFTP Fixed UDP Port:
CONFIG_TFTP_PORT
A better solution is to properly configure the firewall,
but sometimes that is not allowed.
-- Show boot progress:
- CONFIG_SHOW_BOOT_PROGRESS
-
- Defining this option allows to add some board-
- specific code (calling a user-provided function
- "show_boot_progress(int)") that enables you to show
- the system's boot progress on some display (for
- example, some LED's) on your board. At the moment,
- the following checkpoints are implemented:
-
-
-Legacy uImage format:
-
- Arg Where When
- 1 common/cmd_bootm.c before attempting to boot an image
- -1 common/cmd_bootm.c Image header has bad magic number
- 2 common/cmd_bootm.c Image header has correct magic number
- -2 common/cmd_bootm.c Image header has bad checksum
- 3 common/cmd_bootm.c Image header has correct checksum
- -3 common/cmd_bootm.c Image data has bad checksum
- 4 common/cmd_bootm.c Image data has correct checksum
- -4 common/cmd_bootm.c Image is for unsupported architecture
- 5 common/cmd_bootm.c Architecture check OK
- -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
- 6 common/cmd_bootm.c Image Type check OK
- -6 common/cmd_bootm.c gunzip uncompression error
- -7 common/cmd_bootm.c Unimplemented compression type
- 7 common/cmd_bootm.c Uncompression OK
- 8 common/cmd_bootm.c No uncompress/copy overwrite error
- -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
-
- 9 common/image.c Start initial ramdisk verification
- -10 common/image.c Ramdisk header has bad magic number
- -11 common/image.c Ramdisk header has bad checksum
- 10 common/image.c Ramdisk header is OK
- -12 common/image.c Ramdisk data has bad checksum
- 11 common/image.c Ramdisk data has correct checksum
- 12 common/image.c Ramdisk verification complete, start loading
- -13 common/image.c Wrong Image Type (not PPC Linux ramdisk)
- 13 common/image.c Start multifile image verification
- 14 common/image.c No initial ramdisk, no multifile, continue.
-
- 15 arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
-
- -30 arch/powerpc/lib/board.c Fatal error, hang the system
- -31 post/post.c POST test failed, detected by post_output_backlog()
- -32 post/post.c POST test failed, detected by post_run_single()
-
- 34 common/cmd_doc.c before loading a Image from a DOC device
- -35 common/cmd_doc.c Bad usage of "doc" command
- 35 common/cmd_doc.c correct usage of "doc" command
- -36 common/cmd_doc.c No boot device
- 36 common/cmd_doc.c correct boot device
- -37 common/cmd_doc.c Unknown Chip ID on boot device
- 37 common/cmd_doc.c correct chip ID found, device available
- -38 common/cmd_doc.c Read Error on boot device
- 38 common/cmd_doc.c reading Image header from DOC device OK
- -39 common/cmd_doc.c Image header has bad magic number
- 39 common/cmd_doc.c Image header has correct magic number
- -40 common/cmd_doc.c Error reading Image from DOC device
- 40 common/cmd_doc.c Image header has correct magic number
- 41 common/cmd_ide.c before loading a Image from a IDE device
- -42 common/cmd_ide.c Bad usage of "ide" command
- 42 common/cmd_ide.c correct usage of "ide" command
- -43 common/cmd_ide.c No boot device
- 43 common/cmd_ide.c boot device found
- -44 common/cmd_ide.c Device not available
- 44 common/cmd_ide.c Device available
- -45 common/cmd_ide.c wrong partition selected
- 45 common/cmd_ide.c partition selected
- -46 common/cmd_ide.c Unknown partition table
- 46 common/cmd_ide.c valid partition table found
- -47 common/cmd_ide.c Invalid partition type
- 47 common/cmd_ide.c correct partition type
- -48 common/cmd_ide.c Error reading Image Header on boot device
- 48 common/cmd_ide.c reading Image Header from IDE device OK
- -49 common/cmd_ide.c Image header has bad magic number
- 49 common/cmd_ide.c Image header has correct magic number
- -50 common/cmd_ide.c Image header has bad checksum
- 50 common/cmd_ide.c Image header has correct checksum
- -51 common/cmd_ide.c Error reading Image from IDE device
- 51 common/cmd_ide.c reading Image from IDE device OK
- 52 common/cmd_nand.c before loading a Image from a NAND device
- -53 common/cmd_nand.c Bad usage of "nand" command
- 53 common/cmd_nand.c correct usage of "nand" command
- -54 common/cmd_nand.c No boot device
- 54 common/cmd_nand.c boot device found
- -55 common/cmd_nand.c Unknown Chip ID on boot device
- 55 common/cmd_nand.c correct chip ID found, device available
- -56 common/cmd_nand.c Error reading Image Header on boot device
- 56 common/cmd_nand.c reading Image Header from NAND device OK
- -57 common/cmd_nand.c Image header has bad magic number
- 57 common/cmd_nand.c Image header has correct magic number
- -58 common/cmd_nand.c Error reading Image from NAND device
- 58 common/cmd_nand.c reading Image from NAND device OK
-
- -60 common/env_common.c Environment has a bad CRC, using default
-
- 64 net/eth.c starting with Ethernet configuration.
- -64 net/eth.c no Ethernet found.
- 65 net/eth.c Ethernet found.
-
- -80 common/cmd_net.c usage wrong
- 80 common/cmd_net.c before calling net_loop()
- -81 common/cmd_net.c some error in net_loop() occurred
- 81 common/cmd_net.c net_loop() back without error
- -82 common/cmd_net.c size == 0 (File with size 0 loaded)
- 82 common/cmd_net.c trying automatic boot
- 83 common/cmd_net.c running "source" command
- -83 common/cmd_net.c some error in automatic boot or "source" command
- 84 common/cmd_net.c end without errors
-
-FIT uImage format:
-
- Arg Where When
- 100 common/cmd_bootm.c Kernel FIT Image has correct format
- -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
- 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
- -101 common/cmd_bootm.c Can't get configuration for kernel subimage
- 102 common/cmd_bootm.c Kernel unit name specified
- -103 common/cmd_bootm.c Can't get kernel subimage node offset
- 103 common/cmd_bootm.c Found configuration node
- 104 common/cmd_bootm.c Got kernel subimage node offset
- -104 common/cmd_bootm.c Kernel subimage hash verification failed
- 105 common/cmd_bootm.c Kernel subimage hash verification OK
- -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
- 106 common/cmd_bootm.c Architecture check OK
- -106 common/cmd_bootm.c Kernel subimage has wrong type
- 107 common/cmd_bootm.c Kernel subimage type OK
- -107 common/cmd_bootm.c Can't get kernel subimage data/size
- 108 common/cmd_bootm.c Got kernel subimage data/size
- -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
- -109 common/cmd_bootm.c Can't get kernel subimage type
- -110 common/cmd_bootm.c Can't get kernel subimage comp
- -111 common/cmd_bootm.c Can't get kernel subimage os
- -112 common/cmd_bootm.c Can't get kernel subimage load address
- -113 common/cmd_bootm.c Image uncompress/copy overwrite error
-
- 120 common/image.c Start initial ramdisk verification
- -120 common/image.c Ramdisk FIT image has incorrect format
- 121 common/image.c Ramdisk FIT image has correct format
- 122 common/image.c No ramdisk subimage unit name, using configuration
- -122 common/image.c Can't get configuration for ramdisk subimage
- 123 common/image.c Ramdisk unit name specified
- -124 common/image.c Can't get ramdisk subimage node offset
- 125 common/image.c Got ramdisk subimage node offset
- -125 common/image.c Ramdisk subimage hash verification failed
- 126 common/image.c Ramdisk subimage hash verification OK
- -126 common/image.c Ramdisk subimage for unsupported architecture
- 127 common/image.c Architecture check OK
- -127 common/image.c Can't get ramdisk subimage data/size
- 128 common/image.c Got ramdisk subimage data/size
- 129 common/image.c Can't get ramdisk load address
- -129 common/image.c Got ramdisk load address
-
- -130 common/cmd_doc.c Incorrect FIT image format
- 131 common/cmd_doc.c FIT image format OK
-
- -140 common/cmd_ide.c Incorrect FIT image format
- 141 common/cmd_ide.c FIT image format OK
-
- -150 common/cmd_nand.c Incorrect FIT image format
- 151 common/cmd_nand.c FIT image format OK
-
-- Standalone program support:
CONFIG_STANDALONE_LOAD_ADDR
This option defines a board specific value for the
for a more detailed description refer to doc/README.update.
- MTD Support (mtdparts command, UBI support)
- CONFIG_MTD_DEVICE
-
- Adds the MTD device infrastructure from the Linux kernel.
- Needed for mtdparts command support.
-
- CONFIG_MTD_PARTITIONS
-
- Adds the MTD partitioning infrastructure from the Linux
- kernel. Needed for UBI support.
-
-- UBI support
CONFIG_MTD_UBI_WL_THRESHOLD
This parameter defines the maximum difference between the highest
erase counter value and the lowest erase counter value of eraseblocks
When defined, the linker checks that the actual size does
not exceed it.
- CONFIG_SPL_TEXT_BASE
- TEXT_BASE for linking the SPL binary.
-
CONFIG_SPL_RELOC_TEXT_BASE
Address to relocate to. If unspecified, this is equal to
CONFIG_SPL_TEXT_BASE (i.e. no relocation is done).
CONFIG_SPL_NAND_DRIVERS
SPL uses normal NAND drivers, not minimal drivers.
+ CONFIG_SPL_NAND_IDENT
+ SPL uses the chip ID list to identify the NAND flash.
+ Requires CONFIG_SPL_NAND_BASE.
+
CONFIG_SPL_NAND_ECC
Include standard software ECC in the SPL
Defines the size and behavior of the NAND that SPL uses
to read U-Boot
- CONFIG_SPL_NAND_BOOT
- Add support NAND boot
-
CONFIG_SYS_NAND_U_BOOT_OFFS
Location in NAND to read U-Boot from
If defined, don't allow the -f switch to env set override variable
access flags.
-- CONFIG_USE_STDINT
- If stdint.h is available with your toolchain you can define this
- option to enable it. You can provide option 'USE_STDINT=1' when
- building U-Boot to enable this.
-
The following definitions that deal with the placement and management
of environment data (variable area); in general, we support the
following configurations:
- CONFIG_SYS_SRIOn_MEM_VIRT:
Virtual Address of SRIO port 'n' memory region
-- CONFIG_SYS_SRIOn_MEM_PHYS:
+- CONFIG_SYS_SRIOn_MEM_PHYxS:
Physical Address of SRIO port 'n' memory region
- CONFIG_SYS_SRIOn_MEM_SIZE:
a 16 bit bus.
Not all NAND drivers use this symbol.
Example of drivers that use it:
- - drivers/mtd/nand/ndfc.c
- - drivers/mtd/nand/mxc_nand.c
+ - drivers/mtd/nand/raw/ndfc.c
+ - drivers/mtd/nand/raw/mxc_nand.c
- CONFIG_SYS_NDFC_EBC0_CFG
Sets the EBC0_CFG register for the NDFC. If not defined
instruction cache) is still performed.
- CONFIG_SPL_BUILD
- Modifies the behaviour of start.S when compiling a loader
- that is executed before the actual U-Boot. E.g. when
- compiling a NAND SPL.
+ Set when the currently-running compilation is for an artifact
+ that will end up in the SPL (as opposed to the TPL or U-Boot
+ proper). Code that needs stage-specific behavior should check
+ this.
- CONFIG_TPL_BUILD
- Modifies the behaviour of start.S when compiling a loader
- that is executed after the SPL and before the actual U-Boot.
- It is loaded by the SPL.
+ Set when the currently-running compilation is for an artifact
+ that will end up in the TPL (as opposed to the SPL or U-Boot
+ proper). Code that needs stage-specific behavior should check
+ this.
- CONFIG_SYS_MPC85XX_NO_RESETVEC
Only for 85xx systems. If this variable is specified, the section
- CONFIG_SYS_NAND_NO_SUBPAGE_WRITE
Option to disable subpage write in NAND driver
driver that uses this:
- drivers/mtd/nand/davinci_nand.c
+ drivers/mtd/nand/raw/davinci_nand.c
Freescale QE/FMAN Firmware Support:
-----------------------------------
- CONFIG_SYS_FMAN_FW_ADDR
The address in the storage device where the FMAN microcode is located. The
- meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
+ meaning of this address depends on which CONFIG_SYS_QE_FMAN_FW_IN_xxx macro
is also specified.
- CONFIG_SYS_QE_FW_ADDR
The address in the storage device where the QE microcode is located. The
- meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
+ meaning of this address depends on which CONFIG_SYS_QE_FMAN_FW_IN_xxx macro
is also specified.
- CONFIG_SYS_QE_FMAN_FW_LENGTH
If you have modified U-Boot sources (for instance added a new board
or support for new devices, a new CPU, etc.) you are expected to
provide feedback to the other developers. The feedback normally takes
-the form of a "patch", i. e. a context diff against a certain (latest
+the form of a "patch", i.e. a context diff against a certain (latest
official or latest in the git repository) version of U-Boot sources.
But before you submit such a patch, please verify that your modifi-
allowed for use by the bootm command. See also "bootm_low"
environment variable.
+ bootstopkeysha256, bootdelaykey, bootstopkey - See README.autoboot
+
updatefile - Location of the software update file on a TFTP server, used
by the automatic software update feature. Please refer to
documentation in doc/README.update for more details.
regular expression. This allows multiple variables to be connected to
the same callback without explicitly listing them all out.
+The signature of the callback functions is:
+
+ int callback(const char *name, const char *value, enum env_op op, int flags)
+
+* name - changed environment variable
+* value - new value of the environment variable
+* op - operation (create, overwrite, or delete)
+* flags - attributes of the environment variable change, see flags H_* in
+ include/search.h
+
+The return value is 0 if the variable change is accepted and 1 otherwise.
Command Line Parsing:
=====================