/m68k Files generic to m68k architecture
/microblaze Files generic to microblaze architecture
/mips Files generic to MIPS architecture
- /nds32 Files generic to NDS32 architecture
/nios2 Files generic to Altera NIOS2 architecture
/powerpc Files generic to PowerPC architecture
/riscv Files generic to RISC-V architecture
See Freescale App Note 4493 for more information about
this erratum.
- CONFIG_A003399_NOR_WORKAROUND
- Enables a workaround for IFC erratum A003399. It is only
- required during NOR boot.
-
- CONFIG_A008044_WORKAROUND
- Enables a workaround for T1040/T1042 erratum A008044. It is only
- required during NAND boot and valid for Rev 1.0 SoC revision
-
CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY
This is the value to write into CCSR offset 0x18600
This CONFIG is defined when the CPC is configured as SRAM at the
time of U-Boot entry and is required to be re-initialized.
- CONFIG_DEEP_SLEEP
- Indicates this SoC supports deep sleep feature. If deep sleep is
- supported, core will start to execute uboot when wakes up.
-
- Generic CPU options:
CONFIG_SYS_BIG_ENDIAN, CONFIG_SYS_LITTLE_ENDIAN
CONFIG_SYS_FSL_OTHER_DDR_NUM_CTRLS
Number of controllers used for other than main memory.
- CONFIG_SYS_FSL_HAS_DP_DDR
- Defines the SoC has DP-DDR used for DPAA.
-
CONFIG_SYS_FSL_SEC_BE
Defines the SEC controller register space as Big Endian
boards with QUICC Engines require OF_QE to set UCC MAC
addresses
- CONFIG_OF_BOARD_SETUP
-
- Board code has addition modification that it wants to make
- to the flat device tree before handing it off to the kernel
-
- CONFIG_OF_SYSTEM_SETUP
-
- Other code has addition modification that it wants to make
- to the flat device tree before handing it off to the kernel.
- This causes ft_system_setup() to be called before booting
- the kernel.
-
CONFIG_OF_IDE_FIXUP
U-Boot can detect if an IDE device is present or not.
Note: If a "bootargs" environment is defined, it will override
the defaults discussed just above.
-- Cache Configuration:
- CONFIG_SYS_L2CACHE_OFF- Do not enable L2 cache in U-Boot
-
- Cache Configuration for ARM:
CONFIG_SYS_L2_PL310 - Enable support for ARM PL310 L2 cache
controller
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
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_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
- support for the SoC. There must be support in the SoC
- specific code for a watchdog. For the 8xx
- CPUs, the SIU Watchdog feature is enabled in the SYPCR
- register. When supported for a specific SoC is
- available, then no further board specific code should
- be needed to use it.
-
- CONFIG_HW_WATCHDOG
- When using a watchdog circuitry external to the used
- SoC, then define this variable and provide board
- specific code for the "hw_watchdog_reset" function.
-
CONFIG_SYS_WATCHDOG_FREQ
Some platforms automatically call WATCHDOG_RESET()
from the timer interrupt handler every
CONFIG_SCSI) you must configure support for at
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)
- which has to be defined in a board specific file
-
-- ATAPI Support:
- CONFIG_ATAPI
-
- Set this to enable ATAPI support.
-
- LBA48 Support
CONFIG_LBA48
When enabled, makes the IDE subsystem use 64bit sector addresses.
Default is 32bit.
-- SCSI Support:
- CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and
- CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID *
- CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the
- maximum numbers of LUNs, SCSI ID's and target
- devices.
-
- The environment variable 'scsidevs' is set to the number of
- 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.
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
sending again an USB request to the device.
- Journaling Flash filesystem support:
- CONFIG_JFFS2_NAND
- Define these for a default partition on a NAND device
-
CONFIG_SYS_JFFS2_FIRST_SECTOR,
CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS
Define these for a default partition on a NOR device
- 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
- SOCs that have a DIU should define this macro to enable DIU
- support, and should also define these other macros:
-
- CONFIG_SYS_DIU_ADDR
- CONFIG_VIDEO
- 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
- variable, and if defined, enable the DIU as a console during
- boot. See the documentation file doc/README.video for a
- description of this variable.
-
- LCD Support: CONFIG_LCD
Define this to enable LCD support (for output to LCD
display); also select one of the supported displays
by defining one of these:
- CONFIG_ATMEL_LCD:
-
- HITACHI TX09D70VM1CCA, 3.5", 240x320.
-
CONFIG_NEC_NL6448AC33:
NEC NL6448AC33-18. Active, color, single scan.
If CONFIG_LCD_ROTATION is not defined, the console will be
initialized with 0degree rotation.
- CONFIG_LCD_BMP_RLE8
-
- 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)
The clock frequency of the MII bus
- CONFIG_PHY_RESET_DELAY
-
- Some PHY like Intel LXT971A need extra delay after
- reset before any MII register access is possible.
- For such PHY, set this option to the usec delay
- required. (minimum 300usec for LXT971A)
-
CONFIG_PHY_CMD_DELAY (ppc4xx)
Some PHY like Intel LXT971A need extra delay after
server to contact when using the "tftboot" command.
(Environment variable "serverip")
- CONFIG_KEEP_SERVERADDR
-
- Keeps the server's MAC address, in the env 'serveraddr'
- for passing to bootargs (like Linux's netconsole option)
-
- Gateway IP address:
CONFIG_GATEWAYIP
from a BOOTP client in networks with unusually high latency.
- DHCP Advanced Options:
- You can fine tune the DHCP functionality by defining
- CONFIG_BOOTP_* symbols:
-
- CONFIG_BOOTP_NISDOMAIN
- CONFIG_BOOTP_BOOTFILESIZE
- CONFIG_BOOTP_NTPSERVER
- CONFIG_BOOTP_TIMEOFFSET
- CONFIG_BOOTP_VENDOREX
- CONFIG_BOOTP_MAY_FAIL
-
- CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
- environment variable, not the BOOTP server.
-
- CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
- after the configured retry count, the call will fail
- instead of starting over. This can be used to fail over
- to Link-local IP address configuration if the DHCP server
- is not available.
-
- CONFIG_BOOTP_DHCP_REQUEST_DELAY
-
- A 32bit value in microseconds for a delay between
- receiving a "DHCP Offer" and sending the "DHCP Request".
- This fixes a problem with certain DHCP servers that don't
- respond 100% of the time to a "DHCP request". E.g. On an
- AT91RM9200 processor running at 180MHz, this delay needed
- to be *at least* 15,000 usec before a Windows Server 2003
- DHCP server would reply 100% of the time. I recommend at
- least 50,000 usec to be safe. The alternative is to hope
- that one of the retries will be successful but note that
- the DHCP timeout and retry process takes a longer than
- this delay.
- Link-local IP address negotiation:
Negotiate with other link-local clients on the local network
SPI EEPROM, also an instance works with Crystal A/D and
D/As on the SACSng board)
- CONFIG_SOFT_SPI
-
- Enables a software (bit-bang) SPI driver rather than
- using hardware support. This is a general purpose
- driver that only requires three general I/O port pins
- (two outputs, one input) to function. If this is
- defined, the board configuration must define several
- SPI configuration items (port pins to use, etc). For
- an example, see include/configs/sacsng.h.
-
CONFIG_SYS_SPI_MXC_WAIT
Timeout for waiting until spi transfer completed.
default: (CONFIG_SYS_HZ/100) /* 10 ms */
Time to wait after FPGA configuration. The default is
200 ms.
-- Configuration Management:
-
- CONFIG_IDENT_STRING
-
- If defined, this string will be added to the U-Boot
- version information (U_BOOT_VERSION)
-
- Vendor Parameter Protection:
U-Boot considers the values of the environment
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
-
- This variable defines the number of retries for
- network operations like ARP, RARP, TFTP, or BOOTP
- before giving up the operation. If not defined, a
- default value of 5 is used.
-
- CONFIG_ARP_TIMEOUT
-
- Timeout waiting for an ARP reply in milliseconds.
-
- CONFIG_NFS_TIMEOUT
-
- Timeout in milliseconds used in NFS protocol.
- If you encounter "ERROR: Cannot umount" in nfs command,
- try longer timeout such as
- #define CONFIG_NFS_TIMEOUT 10000UL
-
Note:
In the current implementation, the local variables
of the backslashes before semicolons and special
symbols.
-- Command Line Editing and History:
- CONFIG_CMDLINE_PS_SUPPORT
-
- Enable support for changing the command prompt string
- at run-time. Only static string is supported so far.
- The string is obtained from environment variables PS1
- and PS2.
-
- Default Environment:
CONFIG_EXTRA_ENV_SETTINGS
this is instead controlled by the value of
/config/load-environment.
-- TFTP Fixed UDP Port:
- CONFIG_TFTP_PORT
-
- If this is defined, the environment variable tftpsrcp
- is used to supply the TFTP UDP source port value.
- If tftpsrcp isn't defined, the normal pseudo-random port
- number generator is used.
-
- Also, the environment variable tftpdstp is used to supply
- the TFTP UDP destination port value. If tftpdstp isn't
- defined, the normal port 69 is used.
-
- The purpose for tftpsrcp is to allow a TFTP server to
- blindly start the TFTP transfer using the pre-configured
- target IP address and UDP port. This has the effect of
- "punching through" the (Windows XP) firewall, allowing
- the remainder of the TFTP transfer to proceed normally.
- A better solution is to properly configure the firewall,
- but sometimes that is not allowed.
-
CONFIG_STANDALONE_LOAD_ADDR
This option defines a board specific value for the
CONFIG_SPL_INIT_MINIMAL
Arch init code should be built for a very small image
- CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_PARTITION
- Partition on the MMC to load U-Boot from when the MMC is being
- used in raw mode
-
- CONFIG_SYS_MMCSD_RAW_MODE_KERNEL_SECTOR
- Sector to load kernel uImage from when MMC is being
- used in raw mode (for Falcon mode)
-
CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTOR,
CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTORS
Sector and number of sectors to load kernel argument
CONFIG_SPL_SKIP_RELOCATE
Avoid SPL relocation
- CONFIG_SPL_NAND_IDENT
- SPL uses the chip ID list to identify the NAND flash.
- Requires CONFIG_SPL_NAND_BASE.
-
CONFIG_SPL_UBI
Support for a lightweight UBI (fastmap) scanner and
loader
- CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
- CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
- CONFIG_BOARD_LATE_INIT: Call board_late_init()
-- CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()
Configuration Settings:
-----------------------
the RAM base is not zero, or RAM is divided into banks,
this variable needs to be recalcuated to get the address.
-- CONFIG_SYS_MEM_TOP_HIDE:
- If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
- this specified memory area will get subtracted from the top
- (end) of RAM and won't get "touched" at all by U-Boot. By
- fixing up gd->ram_size the Linux kernel should gets passed
- the now "corrected" memory size and won't touch it either.
- This should work for arch/ppc and arch/powerpc. Only Linux
- board ports in arch/powerpc with bootwrapper support that
- recalculate the memory size from the SDRAM controller setup
- will have to get fixed in Linux additionally.
-
- This option can be used as a workaround for the 440EPx/GRx
- CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
- be touched.
-
- WARNING: Please make sure that this value is a multiple of
- the Linux page size (normally 4k). If this is not the case,
- then the end address of the Linux memory will be located at a
- non page size aligned address and this could cause major
- problems.
-
- CONFIG_SYS_LOADS_BAUD_CHANGE:
Enable temporary baudrate change while serial download
- CONFIG_SYS_FLASH_BASE:
Physical start address of Flash memory.
-- CONFIG_SYS_MONITOR_BASE:
- Physical start address of boot monitor code (set by
- make config files to be same as the text base address
- (CONFIG_SYS_TEXT_BASE) used when linking) - same as
- CONFIG_SYS_FLASH_BASE when booting from flash.
-
- CONFIG_SYS_MONITOR_LEN:
Size of memory reserved for monitor code, used to
determine _at_compile_time_ (!) if the environment is
Enables allocating and saving a kernel copy of the bd_info in
space between "bootm_low" and "bootm_low" + BOOTMAPSZ.
-- CONFIG_SYS_MAX_FLASH_BANKS:
- Max number of Flash memory banks
-
- CONFIG_SYS_MAX_FLASH_SECT:
Max number of sectors on a Flash chip
while unprotecting/erasing/programming. Please only enable
this option if you really know what you are doing.
-- CONFIG_SYS_RX_ETH_BUFFER:
- Defines the number of Ethernet receive buffers. On some
- Ethernet controllers it is recommended to set this value
- to 8 or even higher (EEPRO100 or 405 EMAC), since all
- buffers can be full shortly after enabling the interface
- on high Ethernet traffic.
- Defaults to 4 if not defined.
-
- CONFIG_ENV_MAX_ENTRIES
Maximum number of entries in the hash table that is used
the default environment is used; a new CRC is computed as soon as you
use the "saveenv" command to store a valid environment.
-- CONFIG_SYS_FAULT_ECHO_LINK_DOWN:
- Echo the inverted Ethernet link state to the fault LED.
-
- Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR
- also needs to be defined.
-
- CONFIG_SYS_FAULT_MII_ADDR:
MII address of the PHY to check for the Ethernet link state.
later, once stdio is running and output goes to the LCD, if
present.
-- CONFIG_BOARD_SIZE_LIMIT:
- Maximum size of the U-Boot image. When defined, the
- build system checks that the actual size does not
- exceed it.
-
Low Level (hardware related) configuration options:
---------------------------------------------------
If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be
forced to a value that ensures that CCSR is not relocated.
-- CONFIG_IDE_AHB:
- Most IDE controllers were designed to be connected with PCI
- interface. Only few of them were designed for AHB interface.
- When software is doing ATA command and data transfer to
- IDE devices through IDE-AHB controller, some additional
- registers accessing to these kind of IDE-AHB controller
- is required.
-
- CONFIG_SYS_IMMR: Physical address of the Internal Memory.
DO NOT CHANGE unless you know exactly what you're
doing! (11-4) [MPC8xx systems only]
- 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_SYS_SRIO:
Chip has SRIO or not
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:
=======================================
* Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
LynxOS, pSOS, QNX, RTEMS, INTEGRITY;
- Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
- INTEGRITY).
+ Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, INTEGRITY).
* Target CPU Architecture (Provisions for Alpha, ARM, Intel x86,
- IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
- Currently supported: ARM, Intel x86, MIPS, NDS32, Nios II, PowerPC).
+ IA64, MIPS, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
+ Currently supported: ARM, Intel x86, MIPS, Nios II, PowerPC).
* Compression Type (uncompressed, gzip, bzip2)
* Load Address
* Entry Point
Note: on Nios II, we give "-G0" option to gcc and don't use gp
to access small data sections, so gp is free.
-On NDS32, the following registers are used:
-
- R0-R1: argument/return
- R2-R5: argument
- R15: temporary register for assembler
- R16: trampoline register
- R28: frame pointer (FP)
- R29: global pointer (GP)
- R30: link register (LP)
- R31: stack pointer (SP)
- PC: program counter (PC)
-
- ==> U-Boot will use R10 to hold a pointer to the global data
-
-NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
-or current versions of GCC may "optimize" the code too much.
-
On RISC-V, the following registers are used:
x0: hard-wired zero (zero)
projects / u-boot.git / blobdiff