mtd: nand: report ECC errors properly when reading BBT

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Gitweb:     http://git.infradead.org/?p=mtd-2.6.git;a=commit;h=167a8d52509a0f7d6728a79e2588b800e866c147
Commit:     167a8d52509a0f7d6728a79e2588b800e866c147
Parent:     d57f40544a41fdfe90fd863b6865138c5a82f1cc
Author:     Brian Norris <computersforpeace at gmail.com>
AuthorDate: Tue Sep 20 18:35:08 2011 -0700
Committer:  Artem Bityutskiy <artem.bityutskiy at intel.com>
CommitDate: Wed Sep 21 09:19:07 2011 +0300

    mtd: nand: report ECC errors properly when reading BBT
    
    Instead of just printing a warning when encountering ECC errors, we
    should return a proper error status and print a more informative
    warning. Later, we will handle these error messages in the upper layers
    of the BBT scan.
    
    Note that this patch makes our check for ECC error codes a little bit
    more restrictive, leaving all unrecognized errors to the generic "else"
    clause. This shouldn't cause problems and could even be a benefit.
    
    This code is based on some findings reported by Matthieu Castet.
    
    Reported-by: Matthieu CASTET <matthieu.castet at parrot.com>
    Signed-off-by: Brian Norris <computersforpeace at gmail.com>
    Signed-off-by: Artem Bityutskiy <artem.bityutskiy at intel.com>
---
 drivers/mtd/nand/nand_bbt.c |   17 ++++++++++++-----
 1 files changed, 12 insertions(+), 5 deletions(-)

diff --git a/drivers/mtd/nand/nand_bbt.c b/drivers/mtd/nand/nand_bbt.c
index 584bdcb..0ed8591 100644
--- a/drivers/mtd/nand/nand_bbt.c
+++ b/drivers/mtd/nand/nand_bbt.c
@@ -178,7 +178,7 @@ static u32 add_marker_len(struct nand_bbt_descr *td)
 static int read_bbt(struct mtd_info *mtd, uint8_t *buf, int page, int num,
 		struct nand_bbt_descr *td, int offs)
 {
-	int res, i, j, act = 0;
+	int res, ret = 0, i, j, act = 0;
 	struct nand_chip *this = mtd->priv;
 	size_t retlen, len, totlen;
 	loff_t from;
@@ -204,11 +204,18 @@ static int read_bbt(struct mtd_info *mtd, uint8_t *buf, int page, int num,
 		}
 		res = mtd->read(mtd, from, len, &retlen, buf);
 		if (res < 0) {
-			if (retlen != len) {
-				pr_info("nand_bbt: error reading bad block table\n");
+			if (mtd_is_eccerr(res)) {
+				pr_info("nand_bbt: ECC error in BBT at "
+					"0x%012llx\n", from & ~mtd->writesize);
+				return res;
+			} else if (mtd_is_bitflip(res)) {
+				pr_info("nand_bbt: corrected error in BBT at "
+					"0x%012llx\n", from & ~mtd->writesize);
+				ret = res;
+			} else {
+				pr_info("nand_bbt: error reading BBT\n");
 				return res;
 			}
-			pr_warn("nand_bbt: ECC error while reading bad block table\n");
 		}
 
 		/* Analyse data */
@@ -242,7 +249,7 @@ static int read_bbt(struct mtd_info *mtd, uint8_t *buf, int page, int num,
 		totlen -= len;
 		from += len;
 	}
-	return 0;
+	return ret;
 }
 
 /**