/xtensa Files generic to Xtensa architecture
/api Machine/arch-independent API for external apps
/board Board-dependent files
+/boot Support for images and booting
/cmd U-Boot commands functions
/common Misc architecture-independent functions
/configs Board default configuration files
- loads U-Boot or (in falcon mode) Linux
-
Configuration Options:
----------------------
CONFIG_SYS_FSL_LBC_CLK_DIV
Defines divider of platform clock(clock input to eLBC controller).
- CONFIG_SYS_FSL_PBL_PBI
- It enables addition of RCW (Power on reset configuration) in built image.
- Please refer doc/README.pblimage for more details
-
- CONFIG_SYS_FSL_PBL_RCW
- It adds PBI(pre-boot instructions) commands in u-boot build image.
- PBI commands can be used to configure SoC before it starts the execution.
- Please refer doc/README.pblimage for more details
-
CONFIG_SYS_FSL_DDR_BE
Defines the DDR controller register space as Big Endian
crash. This is needed for buggy hardware (uc101) where
no pull down resistor is connected to the signal IDE5V_DD7.
- CONFIG_MACH_TYPE [relevant for ARM only][mandatory]
-
- This setting is mandatory for all boards that have only one
- machine type and must be used to specify the machine type
- number as it appears in the ARM machine registry
- (see https://www.arm.linux.org.uk/developer/machines/).
- Only boards that have multiple machine types supported
- in a single configuration file and the machine type is
- runtime discoverable, do not have to use this setting.
-
- vxWorks boot parameters:
bootvx constructs a valid bootline using the following
controller register space
- Serial Ports:
- CONFIG_PL011_SERIAL
-
- Define this if you want support for Amba PrimeCell PL011 UARTs.
-
CONFIG_PL011_CLOCK
If you have Amba PrimeCell PL011 UARTs, set this variable to
Define this variable to enable hw flow control in serial driver.
Current user of this option is drivers/serial/nsl16550.c driver
-- Autoboot Command:
- CONFIG_BOOTCOMMAND
- Only needed when CONFIG_BOOTDELAY is enabled;
- define a command string that is automatically executed
- when no character is read on the console interface
- within "Boot Delay" after reset.
-
- CONFIG_RAMBOOT and CONFIG_NFSBOOT
- The value of these goes into the environment as
- "ramboot" and "nfsboot" respectively, and can be used
- as a convenience, when switching between booting from
- RAM and NFS.
-
- Serial Download Echo Mode:
CONFIG_LOADS_ECHO
If defined to 1, all characters received during a
time on others. This setting #define's the initial
value of the "loads_echo" environment variable.
-- Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
- CONFIG_KGDB_BAUDRATE
- Select one of the baudrates listed in
- CONFIG_SYS_BAUDRATE_TABLE, see below.
-
- Removal of commands
If no commands are needed to boot, you can disable
CONFIG_CMDLINE to remove them. In this case, the command line
which adds regex support to some commands, as for
example "env grep" and "setexpr".
-- Device tree:
- CONFIG_OF_CONTROL
- If this variable is defined, U-Boot will use a device tree
- to configure its devices, instead of relying on statically
- compiled #defines in the board file. This option is
- experimental and only available on a few boards. The device
- tree is available in the global data as gd->fdt_blob.
-
- U-Boot needs to get its device tree from somewhere. This can
- be done using one of the three options below:
-
- CONFIG_OF_EMBED
- If this variable is defined, U-Boot will embed a device tree
- binary in its image. This device tree file should be in the
- board directory and called <soc>-<board>.dts. The binary file
- is then picked up in board_init_f() and made available through
- the global data structure as gd->fdt_blob.
-
- CONFIG_OF_SEPARATE
- If this variable is defined, U-Boot will build a device tree
- binary. It will be called u-boot.dtb. Architecture-specific
- code will locate it at run-time. Generally this works by:
-
- cat u-boot.bin u-boot.dtb >image.bin
-
- and in fact, U-Boot does this for you, creating a file called
- u-boot-dtb.bin which is useful in the common case. You can
- still use the individual files if you need something more
- exotic.
-
- CONFIG_OF_BOARD
- If this variable is defined, U-Boot will use the device tree
- provided by the board at runtime instead of embedding one with
- the image. Only boards defining board_fdt_blob_setup() support
- this option (see include/fdtdec.h file).
-
- Watchdog:
CONFIG_WATCHDOG
If this variable is defined, it enables watchdog
least one non-MTD partition type as well.
- IDE Reset method:
- CONFIG_IDE_RESET_ROUTINE - this is defined in several
- board configurations files but used nowhere!
-
CONFIG_IDE_RESET - is this is defined, IDE Reset will
be performed by calling the function
ide_set_reset(int reset)
SCSI devices found during the last scan.
- NETWORK Support (PCI):
- CONFIG_E1000
- Support for Intel 8254x/8257x gigabit chips.
-
CONFIG_E1000_SPI
Utility code for direct access to the SPI bus on Intel 8257x.
This does not do anything useful unless you set at least one
of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
- CONFIG_E1000_SPI_GENERIC
- Allow generic access to the SPI bus on the Intel 8257x, for
- example with the "sspi" command.
-
CONFIG_NATSEMI
Support for National dp83815 chips.
Support for National dp8382[01] gigabit chips.
- NETWORK Support (other):
-
- CONFIG_DRIVER_AT91EMAC
- Support for AT91RM9200 EMAC.
-
- CONFIG_RMII
- Define this to use reduced MII inteface
-
- CONFIG_DRIVER_AT91EMAC_QUIET
- If this defined, the driver is quiet.
- The driver doen't show link status messages.
-
CONFIG_CALXEDA_XGMAC
Support for the Calxeda XGMAC device
whether the enumeration has succeded at high speed or full
speed.
- CONFIG_SYS_CONSOLE_IS_IN_ENV
- Define this if you want stdin, stdout &/or stderr to
- be set to usbtty.
-
If you have a USB-IF assigned VendorID then you may wish to
define your own vendor specific values either in BoardName.h
or directly in usbd_vendor_info.h. If you don't define
- Keyboard Support:
See Kconfig help for available keyboard drivers.
- CONFIG_KEYBOARD
-
- Define this to enable a custom keyboard support.
- This simply calls drv_keyboard_init() which must be
- defined in your board-specific files. This option is deprecated
- and is only used by novena. For new boards, use driver model
- instead.
-
- Video support:
CONFIG_FSL_DIU_FB
Enable the Freescale DIU video driver. Reference boards for
CONFIG_CFB_CONSOLE
CONFIG_VIDEO_SW_CURSOR
CONFIG_VGA_AS_SINGLE_DEVICE
- CONFIG_VIDEO_LOGO
CONFIG_VIDEO_BMP_LOGO
The DIU driver will look for the 'video-mode' environment
Support drawing of RLE8-compressed bitmaps on the LCD.
- CONFIG_I2C_EDID
-
- Enables an 'i2c edid' command which can read EDID
- information over I2C from an attached LCD display.
-
- MII/PHY support:
CONFIG_PHY_CLOCK_FREQ (ppc4xx)
HERMES, IP860, RPXlite, LWMON,
FLAGADM
-- Access to physical memory region (> 4GB)
- Some basic support is provided for operations on memory not
- normally accessible to U-Boot - e.g. some architectures
- support access to more than 4GB of memory on 32-bit
- machines using physical address extension or similar.
- Define CONFIG_PHYSMEM to access this basic support, which
- currently only supports clearing the memory.
-
- Error Recovery:
CONFIG_NET_RETRY_COUNT
CONFIG_SPL
Enable building of SPL globally.
- CONFIG_SPL_LDSCRIPT
- LDSCRIPT for linking the SPL binary.
-
CONFIG_SPL_MAX_FOOTPRINT
Maximum size in memory allocated to the SPL, BSS included.
When defined, the linker checks that the actual memory
CONFIG_SYS_SPL_MALLOC_SIZE
The size of the malloc pool used in SPL.
- CONFIG_SPL_OS_BOOT
- Enable booting directly to an OS from SPL.
- See also: doc/README.falcon
-
CONFIG_SPL_DISPLAY_PRINT
For ARM, enable an optional function to print more information
about the running system.
Defines the size and behavior of the NAND that SPL uses
to read U-Boot
- CONFIG_SYS_NAND_U_BOOT_OFFS
- Location in NAND to read U-Boot from
-
CONFIG_SYS_NAND_U_BOOT_DST
Location in memory to load U-Boot to
- CONFIG_SYS_MAMR_PTA:
periodic timer for refresh
-- FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM,
- CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP,
- CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM,
- CONFIG_SYS_BR1_PRELIM:
- Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
-
-- SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
- CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM,
- CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM:
- Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
-
-- CONFIG_PCI_INDIRECT_BRIDGE:
- Enable support for indirect PCI bridges.
-
- CONFIG_SYS_SRIO:
Chip has SRIO or not
This only takes effect if the memory commands are activated
globally (CONFIG_CMD_MEMORY).
-- CONFIG_SKIP_LOWLEVEL_INIT
- [ARM, NDS32, MIPS, RISC-V only] If this variable is defined, then certain
- low level initializations (like setting up the memory
- controller) are omitted and/or U-Boot does not
- relocate itself into RAM.
-
- Normally this variable MUST NOT be defined. The only
- exception is when U-Boot is loaded (to RAM) by some
- other boot loader or by a debugger which performs
- these initializations itself.
-
-- CONFIG_SKIP_LOWLEVEL_INIT_ONLY
- [ARM926EJ-S only] This allows just the call to lowlevel_init()
- to be skipped. The normal CP15 init (such as enabling the
- instruction cache) is still performed.
-
- CONFIG_SPL_BUILD
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
For now: just type "help <command>".
-Environment Variables:
-======================
-
-U-Boot supports user configuration using Environment Variables which
-can be made persistent by saving to Flash memory.
-
-Environment Variables are set using "setenv", printed using
-"printenv", and saved to Flash using "saveenv". Using "setenv"
-without a value can be used to delete a variable from the
-environment. As long as you don't save the environment you are
-working with an in-memory copy. In case the Flash area containing the
-environment is erased by accident, a default environment is provided.
-
-Some configuration options can be set using Environment Variables.
-
-List of environment variables (most likely not complete):
-
- baudrate - see CONFIG_BAUDRATE
-
- bootdelay - see CONFIG_BOOTDELAY
-
- bootcmd - see CONFIG_BOOTCOMMAND
-
- bootargs - Boot arguments when booting an RTOS image
-
- bootfile - Name of the image to load with TFTP
-
- bootm_low - Memory range available for image processing in the bootm
- command can be restricted. This variable is given as
- a hexadecimal number and defines lowest address allowed
- for use by the bootm command. See also "bootm_size"
- environment variable. Address defined by "bootm_low" is
- also the base of the initial memory mapping for the Linux
- kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
- bootm_mapsize.
-
- bootm_mapsize - Size of the initial memory mapping for the Linux kernel.
- This variable is given as a hexadecimal number and it
- defines the size of the memory region starting at base
- address bootm_low that is accessible by the Linux kernel
- during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used
- as the default value if it is defined, and bootm_size is
- used otherwise.
-
- bootm_size - Memory range available for image processing in the bootm
- command can be restricted. This variable is given as
- a hexadecimal number and defines the size of the region
- 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.
-
- autoload - if set to "no" (any string beginning with 'n'),
- "bootp" will just load perform a lookup of the
- configuration from the BOOTP server, but not try to
- load any image using TFTP
-
- autostart - if set to "yes", an image loaded using the "bootp",
- "rarpboot", "tftpboot" or "diskboot" commands will
- be automatically started (by internally calling
- "bootm")
-
- If set to "no", a standalone image passed to the
- "bootm" command will be copied to the load address
- (and eventually uncompressed), but NOT be started.
- This can be used to load and uncompress arbitrary
- data.
-
- fdt_high - if set this restricts the maximum address that the
- flattened device tree will be copied into upon boot.
- For example, if you have a system with 1 GB memory
- at physical address 0x10000000, while Linux kernel
- only recognizes the first 704 MB as low memory, you
- may need to set fdt_high as 0x3C000000 to have the
- device tree blob be copied to the maximum address
- of the 704 MB low memory, so that Linux kernel can
- access it during the boot procedure.
-
- If this is set to the special value 0xFFFFFFFF then
- the fdt will not be copied at all on boot. For this
- to work it must reside in writable memory, have
- sufficient padding on the end of it for u-boot to
- add the information it needs into it, and the memory
- must be accessible by the kernel.
-
- fdtcontroladdr- if set this is the address of the control flattened
- device tree used by U-Boot when CONFIG_OF_CONTROL is
- defined.
-
- i2cfast - (PPC405GP|PPC405EP only)
- if set to 'y' configures Linux I2C driver for fast
- mode (400kHZ). This environment variable is used in
- initialization code. So, for changes to be effective
- it must be saved and board must be reset.
-
- initrd_high - restrict positioning of initrd images:
- If this variable is not set, initrd images will be
- copied to the highest possible address in RAM; this
- is usually what you want since it allows for
- maximum initrd size. If for some reason you want to
- make sure that the initrd image is loaded below the
- CONFIG_SYS_BOOTMAPSZ limit, you can set this environment
- variable to a value of "no" or "off" or "0".
- Alternatively, you can set it to a maximum upper
- address to use (U-Boot will still check that it
- does not overwrite the U-Boot stack and data).
-
- For instance, when you have a system with 16 MB
- RAM, and want to reserve 4 MB from use by Linux,
- you can do this by adding "mem=12M" to the value of
- the "bootargs" variable. However, now you must make
- sure that the initrd image is placed in the first
- 12 MB as well - this can be done with
-
- setenv initrd_high 00c00000
-
- If you set initrd_high to 0xFFFFFFFF, this is an
- indication to U-Boot that all addresses are legal
- for the Linux kernel, including addresses in flash
- memory. In this case U-Boot will NOT COPY the
- ramdisk at all. This may be useful to reduce the
- boot time on your system, but requires that this
- feature is supported by your Linux kernel.
-
- ipaddr - IP address; needed for tftpboot command
-
- loadaddr - Default load address for commands like "bootp",
- "rarpboot", "tftpboot", "loadb" or "diskboot"
-
- loads_echo - see CONFIG_LOADS_ECHO
-
- serverip - TFTP server IP address; needed for tftpboot command
-
- bootretry - see CONFIG_BOOT_RETRY_TIME
-
- bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
-
- bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
-
- ethprime - controls which interface is used first.
-
- ethact - controls which interface is currently active.
- For example you can do the following
-
- => setenv ethact FEC
- => ping 192.168.0.1 # traffic sent on FEC
- => setenv ethact SCC
- => ping 10.0.0.1 # traffic sent on SCC
-
- ethrotate - When set to "no" U-Boot does not go through all
- available network interfaces.
- It just stays at the currently selected interface.
-
- netretry - When set to "no" each network operation will
- either succeed or fail without retrying.
- When set to "once" the network operation will
- fail when all the available network interfaces
- are tried once without success.
- Useful on scripts which control the retry operation
- themselves.
-
- npe_ucode - set load address for the NPE microcode
-
- silent_linux - If set then Linux will be told to boot silently, by
- changing the console to be empty. If "yes" it will be
- made silent. If "no" it will not be made silent. If
- unset, then it will be made silent if the U-Boot console
- is silent.
-
- tftpsrcp - If this is set, the value is used for TFTP's
- UDP source port.
-
- tftpdstp - If this is set, the value is used for TFTP's UDP
- destination port instead of the Well Know Port 69.
-
- tftpblocksize - Block size to use for TFTP transfers; if not set,
- we use the TFTP server's default block size
-
- tftptimeout - Retransmission timeout for TFTP packets (in milli-
- seconds, minimum value is 1000 = 1 second). Defines
- when a packet is considered to be lost so it has to
- be retransmitted. The default is 5000 = 5 seconds.
- Lowering this value may make downloads succeed
- faster in networks with high packet loss rates or
- with unreliable TFTP servers.
-
- tftptimeoutcountmax - maximum count of TFTP timeouts (no
- unit, minimum value = 0). Defines how many timeouts
- can happen during a single file transfer before that
- transfer is aborted. The default is 10, and 0 means
- 'no timeouts allowed'. Increasing this value may help
- downloads succeed with high packet loss rates, or with
- unreliable TFTP servers or client hardware.
-
- tftpwindowsize - if this is set, the value is used for TFTP's
- window size as described by RFC 7440.
- This means the count of blocks we can receive before
- sending ack to server.
-
- vlan - When set to a value < 4095 the traffic over
- Ethernet is encapsulated/received over 802.1q
- VLAN tagged frames.
-
- bootpretryperiod - Period during which BOOTP/DHCP sends retries.
- Unsigned value, in milliseconds. If not set, the period will
- be either the default (28000), or a value based on
- CONFIG_NET_RETRY_COUNT, if defined. This value has
- precedence over the valu based on CONFIG_NET_RETRY_COUNT.
-
- memmatches - Number of matches found by the last 'ms' command, in hex
-
- memaddr - Address of the last match found by the 'ms' command, in hex,
- or 0 if none
-
- mempos - Index position of the last match found by the 'ms' command,
- in units of the size (.b, .w, .l) of the search
-
- zbootbase - (x86 only) Base address of the bzImage 'setup' block
-
- zbootaddr - (x86 only) Address of the loaded bzImage, typically
- BZIMAGE_LOAD_ADDR which is 0x100000
-
-The following image location variables contain the location of images
-used in booting. The "Image" column gives the role of the image and is
-not an environment variable name. The other columns are environment
-variable names. "File Name" gives the name of the file on a TFTP
-server, "RAM Address" gives the location in RAM the image will be
-loaded to, and "Flash Location" gives the image's address in NOR
-flash or offset in NAND flash.
-
-*Note* - these variables don't have to be defined for all boards, some
-boards currently use other variables for these purposes, and some
-boards use these variables for other purposes.
-
-Image File Name RAM Address Flash Location
------ --------- ----------- --------------
-u-boot u-boot u-boot_addr_r u-boot_addr
-Linux kernel bootfile kernel_addr_r kernel_addr
-device tree blob fdtfile fdt_addr_r fdt_addr
-ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr
-
-The following environment variables may be used and automatically
-updated by the network boot commands ("bootp" and "rarpboot"),
-depending the information provided by your boot server:
-
- bootfile - see above
- dnsip - IP address of your Domain Name Server
- dnsip2 - IP address of your secondary Domain Name Server
- gatewayip - IP address of the Gateway (Router) to use
- hostname - Target hostname
- ipaddr - see above
- netmask - Subnet Mask
- rootpath - Pathname of the root filesystem on the NFS server
- serverip - see above
-
-
-There are two special Environment Variables:
-
- serial# - contains hardware identification information such
- as type string and/or serial number
- ethaddr - Ethernet address
-
-These variables can be set only once (usually during manufacturing of
-the board). U-Boot refuses to delete or overwrite these variables
-once they have been set once.
-
-
-Further special Environment Variables:
-
- ver - Contains the U-Boot version string as printed
- with the "version" command. This variable is
- readonly (see CONFIG_VERSION_VARIABLE).
-
-
-Please note that changes to some configuration parameters may take
-only effect after the next boot (yes, that's just like Windoze :-).
-
-
-Callback functions for environment variables:
----------------------------------------------
-
-For some environment variables, the behavior of u-boot needs to change
-when their values are changed. This functionality allows functions to
-be associated with arbitrary variables. On creation, overwrite, or
-deletion, the callback will provide the opportunity for some side
-effect to happen or for the change to be rejected.
-
-The callbacks are named and associated with a function using the
-U_BOOT_ENV_CALLBACK macro in your board or driver code.
-
-These callbacks are associated with variables in one of two ways. The
-static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC
-in the board configuration to a string that defines a list of
-associations. The list must be in the following format:
-
- entry = variable_name[:callback_name]
- list = entry[,list]
-
-If the callback name is not specified, then the callback is deleted.
-Spaces are also allowed anywhere in the list.
-
-Callbacks can also be associated by defining the ".callbacks" variable
-with the same list format above. Any association in ".callbacks" will
-override any association in the static list. You can define
-CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the
-".callbacks" environment variable in the default or embedded environment.
-
-If CONFIG_REGEX is defined, the variable_name above is evaluated as a
-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.
-
-
Note for Redundant Ethernet Interfaces:
=======================================
projects / platform / kernel / u-boot.git / blobdiff