[PATCH v3 2/2] dfu: mtd: mark bad the MTD block on erase error

[Patrick Delaunay]

In the MTD DFU backend, it is needed to mark the NAND block bad when the
erase failed with the -EIO error, as it is done in UBI and JFFS2 code.

This operation is not done in the MTD framework, but the bad block
tag (in BBM or in BBT) is required to avoid to write data on this block
in the next DFU_OP_WRITE loop in mtd_block_op(): the code skip the bad
blocks, tested by mtd_block_isbad().

Without this patch, when the NAND block become bad on DFU write operation
- low probability on new NAND - the DFU write operation will always failed
because the failing block is never marked bad.

This patch also adds a test to avoid to request an erase operation on a
block already marked bad; this test is not performed in MTD framework
in mtd_erase().

Reviewed-by: Michael Trimarchi <michael at amarulasolutions.com>
Signed-off-by: Patrick Delaunay <patrick.delaunay at foss.st.com>
---

Changes in v3:
- Split serie with trace fix and support of bad block in MTD erase
- Fix trace for "bbt reserved" when mtd_block_isbad return 2

Changes in v2:
- fix mtd_block_isbad offset parameter for erase check
- Add trace when bad block are skipped in erase loop
- Add remaining byte in trace "Limit reached"

 drivers/dfu/dfu_mtd.c | 30 ++++++++++++++++++++++--------
 1 file changed, 22 insertions(+), 8 deletions(-)

diff --git a/drivers/dfu/dfu_mtd.c b/drivers/dfu/dfu_mtd.c
index b764f091786d..271d485d1c9a 100644
--- a/drivers/dfu/dfu_mtd.c
+++ b/drivers/dfu/dfu_mtd.c
@@ -91,22 +91,36 @@ static int mtd_block_op(enum dfu_op op, struct dfu_entity *dfu,
 				return -EIO;
 			}
 
+			/* Skip the block if it is bad, don't erase it again */
+			ret = mtd_block_isbad(mtd, erase_op.addr);
+			if (ret) {
+				printf("Skipping %s at 0x%08llx\n",
+				       ret == 1 ? "bad block" : "bbt reserved",
+				       erase_op.addr);
+				erase_op.addr += mtd->erasesize;
+				continue;
+			}
+
 			ret = mtd_erase(mtd, &erase_op);
 
 			if (ret) {
-				/* Abort if its not a bad block error */
-				if (ret != -EIO) {
-					printf("Failure while erasing at offset 0x%llx\n",
-					       erase_op.fail_addr);
-					return 0;
+				/* If this is not -EIO, we have no idea what to do. */
+				if (ret == -EIO) {
+					printf("Marking bad block at 0x%08llx (%d)\n",
+					       erase_op.fail_addr, ret);
+					ret = mtd_block_markbad(mtd, erase_op.addr);
+				}
+				/* Abort if it is not -EIO or can't mark bad */
+				if (ret) {
+					printf("Failure while erasing at offset 0x%llx (%d)\n",
+					       erase_op.fail_addr, ret);
+					return ret;
 				}
-				printf("Skipping bad block at 0x%08llx\n",
-				       erase_op.addr);
 			} else {
 				remaining -= mtd->erasesize;
 			}
 
-			/* Continue erase behind bad block */
+			/* Continue erase behind the current block */
 			erase_op.addr += mtd->erasesize;
 		}
 	}
-- 
2.25.1