UBI: add image sequence number to EC header

An image sequence number is added to the UBI erase-counter header
to be able determine if the root file system contains a mixture
of old and new images (because the flashing failed to complete).

A change to nolo is also needed for this to take effect.

Signed-off-by: Adrian Hunter <adrian.hunter@nokia.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

1 files changed, 13 insertions, 2 deletions

diff --git a/drivers/mtd/ubi/io.c b/drivers/mtd/ubi/io.c
index c8edbfd09b6..b5871401109 100644
--- a/drivers/mtd/ubi/io.c
+++ b/drivers/mtd/ubi/io.c
@@ -563,15 +563,16 @@ int ubi_io_mark_bad(const struct ubi_device *ubi, int pnum)
  * This function returns zero if the erase counter header is OK, and %1 if
  * not.
  */
-static int validate_ec_hdr(const struct ubi_device *ubi,
+static int validate_ec_hdr(struct ubi_device *ubi,
                            const struct ubi_ec_hdr *ec_hdr)
 {
         long long ec;
-        int vid_hdr_offset, leb_start;
+        int vid_hdr_offset, leb_start, image_seq;
 
         ec = be64_to_cpu(ec_hdr->ec);
         vid_hdr_offset = be32_to_cpu(ec_hdr->vid_hdr_offset);
         leb_start = be32_to_cpu(ec_hdr->data_offset);
+        image_seq = be32_to_cpu(ec_hdr->image_seq);
 
         if (ec_hdr->version != UBI_VERSION) {
                 ubi_err("node with incompatible UBI version found: "
@@ -597,6 +598,15 @@ static int validate_ec_hdr(const struct ubi_device *ubi,
                 goto bad;
         }
 
+        if (!ubi->image_seq_set) {
+                ubi->image_seq = image_seq;
+                ubi->image_seq_set = 1;
+        } else if (ubi->image_seq != image_seq) {
+                ubi_err("bad image sequence number %d, expected %d",
+                        image_seq, ubi->image_seq);
+                goto bad;
+        }
+
         return 0;
 
 bad:
@@ -742,6 +752,7 @@ int ubi_io_write_ec_hdr(struct ubi_device *ubi, int pnum,
         ec_hdr->version = UBI_VERSION;
         ec_hdr->vid_hdr_offset = cpu_to_be32(ubi->vid_hdr_offset);
         ec_hdr->data_offset = cpu_to_be32(ubi->leb_start);
+        ec_hdr->image_seq = cpu_to_be32(ubi->image_seq);
         crc = crc32(UBI_CRC32_INIT, ec_hdr, UBI_EC_HDR_SIZE_CRC);
         ec_hdr->hdr_crc = cpu_to_be32(crc);