* @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.
* 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;
__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));
* (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.