README: Add new NAND env features

CONFIG_ENV_SIZE does not need block alignment.

Document CONFIG_ENV_RANGE and CONFIG_ENV_OFFSET_OOB.

Signed-off-by: Scott Wood <scottwood@freescale.com>
This commit is contained in:
Scott Wood 2010-09-17 14:38:37 -05:00
parent 36650ca9f1
commit fdd813def8
1 changed files with 22 additions and 8 deletions

30
README
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@ -2534,18 +2534,32 @@ to save the current settings.
- CONFIG_ENV_SIZE:
These two #defines specify the offset and size of the environment
area within the first NAND device.
area within the first NAND device. CONFIG_ENV_OFFSET must be
aligned to an erase block boundary.
- CONFIG_ENV_OFFSET_REDUND
- 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.
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_RENDUND must be
aligned to an erase block boundary.
Note: CONFIG_ENV_OFFSET and CONFIG_ENV_OFFSET_REDUND must be aligned
to a block boundary, and CONFIG_ENV_SIZE must be a multiple of
the NAND devices block size.
- 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