openwrt/target/linux/generic/patches-4.4/040-0002-mtd-bcm47xxpart-don-t-fail-because-of-bit-flips.patch

From 36bcc0c9c2bc8f56569cd735ba531a51358d7c2b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <zajec5@gmail.com>
Date: Sun, 6 Dec 2015 11:31:38 +0100
Subject: [PATCH] mtd: bcm47xxpart: don't fail because of bit-flips
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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>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
---
 drivers/mtd/bcm47xxpart.c | 38 ++++++++++++++++++++++----------------
 1 file changed, 22 insertions(+), 16 deletions(-)

--- a/drivers/mtd/bcm47xxpart.c
+++ b/drivers/mtd/bcm47xxpart.c
@@ -66,11 +66,13 @@ static const char *bcm47xxpart_trx_data_
 {
 	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_
 	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_
 		}
 
 		/* 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;
 		}
 
@@ -252,10 +256,11 @@ static int bcm47xxpart_parse(struct mtd_
 		}
 
 		/* 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;
 		}
 
@@ -275,10 +280,11 @@ static int bcm47xxpart_parse(struct mtd_
 		}
 
 		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;
 		}