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>

diff --git a/README b/README
index f997a5d8605e91ff085da24eeaceac926cf9f194..197804e354e1bb36268f7fa56780141b3ecd0714 100644 (file)
--- a/README
+++ b/README
@@ -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.
-
-       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.
+         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.
+
+       - 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