Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/ide-next-2.6

[karo-tx-linux.git] / drivers / mtd / ubi / ubi-media.h

diff --git a/drivers/mtd/ubi/ubi-media.h b/drivers/mtd/ubi/ubi-media.h
index 2ad94040905322528d9d36ec4edadeae15e086a8..503ea9b273094670d0933baafbfbfb04ae6d88cd 100644 (file)
--- a/drivers/mtd/ubi/ubi-media.h
+++ b/drivers/mtd/ubi/ubi-media.h
@@ -129,13 +129,14 @@ enum {
  * @ec: the erase counter
  * @vid_hdr_offset: where the VID header starts
  * @data_offset: where the user data start
+ * @image_seq: image sequence number
  * @padding2: reserved for future, zeroes
  * @hdr_crc: erase counter header CRC checksum
  *
  * The erase counter header takes 64 bytes and has a plenty of unused space for
  * future usage. The unused fields are zeroed. The @version field is used to
  * indicate the version of UBI implementation which is supposed to be able to
- * work with this UBI image. If @version is greater then the current UBI
+ * work with this UBI image. If @version is greater than the current UBI
  * version, the image is rejected. This may be useful in future if something
  * is changed radically. This field is duplicated in the volume identifier
  * header.
@@ -144,6 +145,14 @@ enum {
  * volume identifier header and user data, relative to the beginning of the
  * physical eraseblock. These values have to be the same for all physical
  * eraseblocks.
+ *
+ * The @image_seq field is used to validate a UBI image that has been prepared
+ * for a UBI device. The @image_seq value can be any value, but it must be the
+ * same on all eraseblocks. UBI will ensure that all new erase counter headers
+ * also contain this value, and will check the value when scanning at start-up.
+ * One way to make use of @image_seq is to increase its value by one every time
+ * an image is flashed over an existing image, then, if the flashing does not
+ * complete, UBI will detect the error when scanning.
  */
 struct ubi_ec_hdr {
        __be32  magic;
@@ -152,7 +161,8 @@ struct ubi_ec_hdr {
        __be64  ec; /* Warning: the current limit is 31-bit anyway! */
        __be32  vid_hdr_offset;
        __be32  data_offset;
-       __u8    padding2[36];
+       __be32  image_seq;
+       __u8    padding2[32];
        __be32  hdr_crc;
 } __attribute__ ((packed));
 
@@ -187,7 +197,7 @@ struct ubi_ec_hdr {
  * (sequence number) is used to distinguish between older and newer versions of
  * logical eraseblocks.
  *
- * There are 2 situations when there may be more then one physical eraseblock
+ * There are 2 situations when there may be more than one physical eraseblock
  * corresponding to the same logical eraseblock, i.e., having the same @vol_id
  * and @lnum values in the volume identifier header. Suppose we have a logical
  * eraseblock L and it is mapped to the physical eraseblock P.