env: Move help from README to Kconfig
The CONFIG_ENV_IS_IN_... options which have already been converted to
Kconfig only have a small amount of help. Move the rest of it over from
the README.
Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/common/Kconfig b/common/Kconfig
index e06089b..de7584f 100644
--- a/common/Kconfig
+++ b/common/Kconfig
@@ -184,6 +184,52 @@
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.
+
config ENV_IS_IN_NAND
bool "Environment in a NAND device"
depends on !CHAIN_OF_TRUST
@@ -191,12 +237,65 @@
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 ENV_IS_IN_UBI
bool "Environment in a UBI volume"
depends on !CHAIN_OF_TRUST
help
- Define this if you have a UBI volume which you want to use for the
- environment.
+ 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_NOWHERE
bool "Environment is not stored"