README: document CONFIG_ENV_IS_IN_MMC
Describe the meaning of CONFIG_ENV_IS_IN_MMC, and all related defines that
must or can be set when using that option.
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Reviewed-by: Peter Korsgaard <jacmet@sunsite.dk>
Acked-by: Tom Rini <trini@ti.com>
Signed-off-by: Andy Fleming <afleming@freescale.com>
diff --git a/README b/README
index 33bda8c..f1485ba 100644
--- a/README
+++ b/README
@@ -3645,6 +3645,46 @@
You will probably want to define these to avoid a really noisy system
when storing the env in UBI.
+- 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.
+
+ 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 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_SYS_SPI_INIT_OFFSET
Defines offset to the initial SPI buffer area in DPRAM. The