[PATCH] mtd: bcm47xxpart: don't fail because of bit-flips

[PATCH] mtd: bcm47xxpart: don't fail because of bit-flips

[Rafał Miłecki]

Bit-flip errors may occur on NAND flashes and are harmless. Handle them
gracefully as read content is still reliable and can be parsed.

Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
---
 drivers/mtd/bcm47xxpart.c | 38 ++++++++++++++++++++++----------------
 1 file changed, 22 insertions(+), 16 deletions(-)

diff --git a/drivers/mtd/bcm47xxpart.c b/drivers/mtd/bcm47xxpart.c
index 4450e74..1ab3451 100644
--- a/drivers/mtd/bcm47xxpart.c
+++ b/drivers/mtd/bcm47xxpart.c
@@ -66,11 +66,13 @@ static const char *bcm47xxpart_trx_data_part_name(struct mtd_info *master,
 {
 	uint32_t buf;
 	size_t bytes_read;
+	int err;
 
-	if (mtd_read(master, offset, sizeof(buf), &bytes_read,
-		     (uint8_t *)&buf) < 0) {
-		pr_err("mtd_read error while parsing (offset: 0x%X)!\n",
-			offset);
+	err  = mtd_read(master, offset, sizeof(buf), &bytes_read,
+			(uint8_t *)&buf);
+	if (err && !mtd_is_bitflip(err)) {
+		pr_err("mtd_read error while parsing (offset: 0x%X): %d\n",
+			offset, err);
 		goto out_default;
 	}
 
@@ -95,6 +97,7 @@ static int bcm47xxpart_parse(struct mtd_info *master,
 	int trx_part = -1;
 	int last_trx_part = -1;
 	int possible_nvram_sizes[] = { 0x8000, 0xF000, 0x10000, };
+	int err;
 
 	/*
 	 * Some really old flashes (like AT45DB*) had smaller erasesize-s, but
@@ -128,10 +131,11 @@ static int bcm47xxpart_parse(struct mtd_info *master,
 		}
 
 		/* Read beginning of the block */
-		if (mtd_read(master, offset, BCM47XXPART_BYTES_TO_READ,
-			     &bytes_read, (uint8_t *)buf) < 0) {
-			pr_err("mtd_read error while parsing (offset: 0x%X)!\n",
-			       offset);
+		err = mtd_read(master, offset, BCM47XXPART_BYTES_TO_READ,
+			       &bytes_read, (uint8_t *)buf);
+		if (err && !mtd_is_bitflip(err)) {
+			pr_err("mtd_read error while parsing (offset: 0x%X): %d\n",
+			       offset, err);
 			continue;
 		}
 
@@ -254,10 +258,11 @@ static int bcm47xxpart_parse(struct mtd_info *master,
 		}
 
 		/* Read middle of the block */
-		if (mtd_read(master, offset + 0x8000, 0x4,
-			     &bytes_read, (uint8_t *)buf) < 0) {
-			pr_err("mtd_read error while parsing (offset: 0x%X)!\n",
-			       offset);
+		err = mtd_read(master, offset + 0x8000, 0x4, &bytes_read,
+			       (uint8_t *)buf);
+		if (err && !mtd_is_bitflip(err)) {
+			pr_err("mtd_read error while parsing (offset: 0x%X): %d\n",
+			       offset, err);
 			continue;
 		}
 
@@ -277,10 +282,11 @@ static int bcm47xxpart_parse(struct mtd_info *master,
 		}
 
 		offset = master->size - possible_nvram_sizes[i];
-		if (mtd_read(master, offset, 0x4, &bytes_read,
-			     (uint8_t *)buf) < 0) {
-			pr_err("mtd_read error while reading at offset 0x%X!\n",
-			       offset);
+		err = mtd_read(master, offset, 0x4, &bytes_read,
+			       (uint8_t *)buf);
+		if (err && !mtd_is_bitflip(err)) {
+			pr_err("mtd_read error while reading (offset 0x%X): %d\n",
+			       offset, err);
 			continue;
 		}
 
-- 
1.8.4.5

Re: [PATCH] mtd: bcm47xxpart: don't fail because of bit-flips

[Brian Norris]

On Sun, Dec 06, 2015 at 11:31:38AM +0100, Rafał Miłecki wrote:
> Bit-flip errors may occur on NAND flashes and are harmless. Handle them
> gracefully as read content is still reliable and can be parsed.
> 
> Signed-off-by: Rafał Miłecki <zajec5@gmail.com>

Pushed to l2-mtd.git/next