kernel: handle bad blocks in ubi auto attach code

The first block(s) of the ubi mtd device might be bad. We need to take
care on our own to skip the bad block(s) and read the next one(s).

Don't treat recoverable read errors as fatal and check for the UBI magic
if the data of a block could be recovered using ECC or similar.

Signed-off-by: Mathias Kresin <dev@kresin.me>

diff --git a/target/linux/generic/pending-4.14/490-ubi-auto-attach-mtd-device-named-ubi-or-data-on-boot.patch b/target/linux/generic/pending-4.14/490-ubi-auto-attach-mtd-device-named-ubi-or-data-on-boot.patch
index aa4dc12201d73e9c2b97a1da6609ce9756d4964b..66da310e84b61494fec209f0d557f682c1fb3c87 100644 (file)
--- a/target/linux/generic/pending-4.14/490-ubi-auto-attach-mtd-device-named-ubi-or-data-on-boot.patch
+++ b/target/linux/generic/pending-4.14/490-ubi-auto-attach-mtd-device-named-ubi-or-data-on-boot.patch
@@ -8,7 +8,7 @@ Signed-off-by: Daniel Golle <daniel@makrotopia.org>
 
 --- a/drivers/mtd/ubi/build.c
 +++ b/drivers/mtd/ubi/build.c
-@@ -1171,6 +1171,54 @@ static struct mtd_info * __init open_mtd
+@@ -1171,6 +1171,68 @@ static struct mtd_info * __init open_mtd
        return mtd;
  }
  
@@ -20,6 +20,7 @@ Signed-off-by: Daniel Golle <daniel@makrotopia.org>
 +{
 +      int err;
 +      struct mtd_info *mtd;
++      loff_t offset = 0;
 +      size_t len;
 +      char magic[4];
 +
@@ -31,9 +32,22 @@ Signed-off-by: Daniel Golle <daniel@makrotopia.org>
 +      if (IS_ERR(mtd))
 +              return;
 +
++      /* get the first not bad block */
++      if (mtd_can_have_bb(mtd))
++              while (mtd_block_isbad(mtd, offset)) {
++                      offset += mtd->erasesize;
++
++                      if (offset > mtd->size) {
++                              pr_err("UBI error: Failed to find a non-bad "
++                                     "block on mtd%d\n", mtd->index);
++                              goto cleanup;
++                      }
++              }
++
 +      /* check for a valid ubi magic if read from flash was successful */
-+      err = mtd_read(mtd, 0, 4, &len, (void *) magic);
-+      if (!err && len == 4 && strncmp(magic, "UBI#", 4)) {
++      err = mtd_read(mtd, offset, 4, &len, (void *) magic);
++      if ((!err || mtd_is_bitflip(err)) &&
++          len == 4 && strncmp(magic, "UBI#", 4)) {
 +              pr_err("UBI error: no valid UBI magic found inside mtd%d\n", mtd->index);
 +              goto cleanup;
 +      }
@@ -63,7 +77,7 @@ Signed-off-by: Daniel Golle <daniel@makrotopia.org>
  static int __init ubi_init(void)
  {
        int err, i, k;
-@@ -1254,6 +1302,12 @@ static int __init ubi_init(void)
+@@ -1254,6 +1316,12 @@ static int __init ubi_init(void)
                }
        }
  

diff --git a/target/linux/generic/pending-4.9/490-ubi-auto-attach-mtd-device-named-ubi-or-data-on-boot.patch b/target/linux/generic/pending-4.9/490-ubi-auto-attach-mtd-device-named-ubi-or-data-on-boot.patch
index 1436e486ddee54ad98003b94089ba71a0047181b..8b923d17d6342e8fb2bb6b0aa5c041b3ccf5eeba 100644 (file)
--- a/target/linux/generic/pending-4.9/490-ubi-auto-attach-mtd-device-named-ubi-or-data-on-boot.patch
+++ b/target/linux/generic/pending-4.9/490-ubi-auto-attach-mtd-device-named-ubi-or-data-on-boot.patch
@@ -8,7 +8,7 @@ Signed-off-by: Daniel Golle <daniel@makrotopia.org>
 
 --- a/drivers/mtd/ubi/build.c
 +++ b/drivers/mtd/ubi/build.c
-@@ -1226,6 +1226,54 @@ static struct mtd_info * __init open_mtd
+@@ -1226,6 +1226,68 @@ static struct mtd_info * __init open_mtd
        return mtd;
  }
  
@@ -20,6 +20,7 @@ Signed-off-by: Daniel Golle <daniel@makrotopia.org>
 +{
 +      int err;
 +      struct mtd_info *mtd;
++      loff_t offset = 0;
 +      size_t len;
 +      char magic[4];
 +
@@ -31,9 +32,22 @@ Signed-off-by: Daniel Golle <daniel@makrotopia.org>
 +      if (IS_ERR(mtd))
 +              return;
 +
++      /* get the first not bad block */
++      if (mtd_can_have_bb(mtd))
++              while (mtd_block_isbad(mtd, offset)) {
++                      offset += mtd->erasesize;
++
++                      if (offset > mtd->size) {
++                              pr_err("UBI error: Failed to find a non-bad "
++                                     "block on mtd%d\n", mtd->index);
++                              goto cleanup;
++                      }
++              }
++
 +      /* check for a valid ubi magic if read from flash was successful */
-+      err = mtd_read(mtd, 0, 4, &len, (void *) magic);
-+      if (!err && len == 4 && strncmp(magic, "UBI#", 4)) {
++      err = mtd_read(mtd, offset, 4, &len, (void *) magic);
++      if ((!err || mtd_is_bitflip(err)) &&
++          len == 4 && strncmp(magic, "UBI#", 4)) {
 +              pr_err("UBI error: no valid UBI magic found inside mtd%d\n", mtd->index);
 +              goto cleanup;
 +      }
@@ -63,7 +77,7 @@ Signed-off-by: Daniel Golle <daniel@makrotopia.org>
  static int __init ubi_init(void)
  {
        int err, i, k;
-@@ -1309,6 +1357,12 @@ static int __init ubi_init(void)
+@@ -1309,6 +1371,12 @@ static int __init ubi_init(void)
                }
        }