Builds up envcrc with the target environment so that external utils
may easily extract it and embed it in final U-Boot images.
-- CONFIG_ENV_IS_IN_FLASH:
-
- Define this if the environment is in flash memory.
-
- a) The environment occupies one whole flash sector, which is
- "embedded" in the text segment with the U-Boot code. This
- happens usually with "bottom boot sector" or "top boot
- sector" type flash chips, which have several smaller
- sectors at the start or the end. For instance, such a
- layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
- such a case you would place the environment in one of the
- 4 kB sectors - with U-Boot code before and after it. With
- "top boot sector" type flash chips, you would put the
- environment in one of the last sectors, leaving a gap
- between U-Boot and the environment.
-
- - CONFIG_ENV_OFFSET:
-
- Offset of environment data (variable area) to the
- beginning of flash memory; for instance, with bottom boot
- type flash chips the second sector can be used: the offset
- for this sector is given here.
-
- CONFIG_ENV_OFFSET is used relative to CONFIG_SYS_FLASH_BASE.
-
- - CONFIG_ENV_ADDR:
-
- This is just another way to specify the start address of
- the flash sector containing the environment (instead of
- CONFIG_ENV_OFFSET).
-
- - CONFIG_ENV_SECT_SIZE:
-
- Size of the sector containing the environment.
-
-
- b) Sometimes flash chips have few, equal sized, BIG sectors.
- In such a case you don't want to spend a whole sector for
- the environment.
-
- - CONFIG_ENV_SIZE:
-
- If you use this in combination with CONFIG_ENV_IS_IN_FLASH
- and CONFIG_ENV_SECT_SIZE, you can specify to use only a part
- of this flash sector for the environment. This saves
- memory for the RAM copy of the environment.
-
- It may also save flash memory if you decide to use this
- when your environment is "embedded" within U-Boot code,
- since then the remainder of the flash sector could be used
- for U-Boot code. It should be pointed out that this is
- STRONGLY DISCOURAGED from a robustness point of view:
- updating the environment in flash makes it always
- necessary to erase the WHOLE sector. If something goes
- wrong before the contents has been restored from a copy in
- RAM, your target system will be dead.
-
- - CONFIG_ENV_ADDR_REDUND
- CONFIG_ENV_SIZE_REDUND
-
- These settings describe a second storage area used to hold
- a redundant copy of the environment data, so that there is
- a valid backup copy in case there is a power failure during
- a "saveenv" operation.
-
-BE CAREFUL! Any changes to the flash layout, and some changes to the
-source code will make it necessary to adapt <board>/u-boot.lds*
-accordingly!
-
-
- CONFIG_ENV_IS_IN_NVRAM:
Define this if you have some non-volatile memory device
environment stored in a remote NOR flash by SRIO or PCIE link,
but it can not erase, write this NOR flash by SRIO or PCIE interface.
-- CONFIG_ENV_IS_IN_NAND:
-
- Define this if you have a NAND device which you want to use
- for the environment.
-
- - CONFIG_ENV_OFFSET:
- - CONFIG_ENV_SIZE:
-
- These two #defines specify the offset and size of the environment
- area within the first NAND device. CONFIG_ENV_OFFSET must be
- aligned to an erase block boundary.
-
- - CONFIG_ENV_OFFSET_REDUND (optional):
-
- This setting describes a second storage area of CONFIG_ENV_SIZE
- size used to hold a redundant copy of the environment data, so
- that there is a valid backup copy in case there is a power failure
- during a "saveenv" operation. CONFIG_ENV_OFFSET_REDUND must be
- aligned to an erase block boundary.
-
- - CONFIG_ENV_RANGE (optional):
-
- Specifies the length of the region in which the environment
- can be written. This should be a multiple of the NAND device's
- block size. Specifying a range with more erase blocks than
- are needed to hold CONFIG_ENV_SIZE allows bad blocks within
- the range to be avoided.
-
- - CONFIG_ENV_OFFSET_OOB (optional):
-
- Enables support for dynamically retrieving the offset of the
- environment from block zero's out-of-band data. The
- "nand env.oob" command can be used to record this offset.
- Currently, CONFIG_ENV_OFFSET_REDUND is not supported when
- using CONFIG_ENV_OFFSET_OOB.
-
- CONFIG_NAND_ENV_DST
Defines address in RAM to which the nand_spl code should copy the
environment. If redundant environment is used, it will be copied to
CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE.
-- CONFIG_ENV_IS_IN_UBI:
-
- Define this if you have an UBI volume that you want to use for the
- environment. This has the benefit of wear-leveling the environment
- accesses, which is important on NAND.
-
- - CONFIG_ENV_UBI_PART:
-
- Define this to a string that is the mtd partition containing the UBI.
-
- - CONFIG_ENV_UBI_VOLUME:
-
- Define this to the name of the volume that you want to store the
- environment in.
-
- - CONFIG_ENV_UBI_VOLUME_REDUND:
-
- Define this to the name of another volume to store a second copy of
- the environment in. This will enable redundant environments in UBI.
- It is assumed that both volumes are in the same MTD partition.
-
- - CONFIG_UBI_SILENCE_MSG
- - CONFIG_UBIFS_SILENCE_MSG
-
- You will probably want to define these to avoid a really noisy system
- when storing the env in UBI.
-
- CONFIG_ENV_IS_IN_FAT:
Define this if you want to use the FAT file system for the environment.
- CONFIG_FAT_WRITE:
This must be enabled. Otherwise it cannot save the environment file.
-- CONFIG_ENV_IS_IN_MMC:
-
- Define this if you have an MMC device which you want to use for the
- environment.
-
- - CONFIG_SYS_MMC_ENV_DEV:
-
- Specifies which MMC device the environment is stored in.
-
- - CONFIG_SYS_MMC_ENV_PART (optional):
-
- Specifies which MMC partition the environment is stored in. If not
- set, defaults to partition 0, the user area. Common values might be
- 1 (first MMC boot partition), 2 (second MMC boot partition).
-
- - CONFIG_ENV_OFFSET:
- - CONFIG_ENV_SIZE:
-
- These two #defines specify the offset and size of the environment
- area within the specified MMC device.
-
- If offset is positive (the usual case), it is treated as relative to
- the start of the MMC partition. If offset is negative, it is treated
- as relative to the end of the MMC partition. This can be useful if
- your board may be fitted with different MMC devices, which have
- different sizes for the MMC partitions, and you always want the
- environment placed at the very end of the partition, to leave the
- maximum possible space before it, to store other data.
-
- These two values are in units of bytes, but must be aligned to an
- MMC sector boundary.
-
- - CONFIG_ENV_OFFSET_REDUND (optional):
-
- Specifies a second storage area, of CONFIG_ENV_SIZE size, used to
- hold a redundant copy of the environment data. This provides a
- valid backup copy in case the other copy is corrupted, e.g. due
- to a power failure during a "saveenv" operation.
-
- This value may also be positive or negative; this is handled in the
- same way as CONFIG_ENV_OFFSET.
-
- This value is also in units of bytes, but must also be aligned to
- an MMC sector boundary.
-
- - CONFIG_ENV_SIZE_REDUND (optional):
-
- This value need not be set, even when CONFIG_ENV_OFFSET_REDUND is
- set. If this value is set, it must be set to the same value as
- CONFIG_ENV_SIZE.
-
Please note that the environment is read-only until the monitor
has been relocated to RAM and a RAM copy of the environment has been
created; also, when using EEPROM you will have to use getenv_f()
projects / people / ms / u-boot.git / blobdiff