From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pb0-f49.google.com ([209.85.160.49]) by merlin.infradead.org with esmtps (Exim 4.76 #1 (Red Hat Linux)) id 1SiDO8-0004ge-0g for linux-mtd@lists.infradead.org; Fri, 22 Jun 2012 23:35:43 +0000 Received: by mail-pb0-f49.google.com with SMTP id rq13so4463121pbb.36 for ; Fri, 22 Jun 2012 16:35:39 -0700 (PDT) From: Brian Norris To: Subject: [PATCH 8/8] mtd: nand: use ECC, if present, when scanning OOB Date: Fri, 22 Jun 2012 16:35:45 -0700 Message-Id: <1340408145-24531-9-git-send-email-computersforpeace@gmail.com> In-Reply-To: <1340408145-24531-1-git-send-email-computersforpeace@gmail.com> References: <1340408145-24531-1-git-send-email-computersforpeace@gmail.com> Cc: Mike Dunn , Artem Bityutskiy , Sebastian Andrzej Siewior , Shmulik Ladkani , Brian Norris , David Woodhouse List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , scan_read_raw_oob() is used in only in places where the MTD_OPS_PLACE_OOB mode is preferable MTD_OPS_RAW mode, so use MTD_OPS_PLACE_OOB instead. MTD_OPS_PLACE_OOB provides the same functionality with the potential[1] added bonus of error correction. This brings scan_block_full() in line with scan_block_fast() so that they both read bad block markers with MTD_OPS_PLACE_OOB. This can help in preventing 0xff markers (in good blocks) from being interpreted as bad block indicators in the presence of a single bitflip. Note that ECC error codes (EUCLEAN or EBADMSG) are already silently ignored in all users of scan_read_raw_oob(). [1] Few drivers perform proper error correction on OOB data. In those cases, the use of MTD_OPS_RAW vs. MTD_OPS_PLACE_OOB is not significant. Signed-off-by: Brian Norris Cc: Shmulik Ladkani Cc: Mike Dunn Cc: Sebastian Andrzej Siewior --- drivers/mtd/nand/nand_bbt.c | 27 ++++++++++++++++++++------- 1 file changed, 20 insertions(+), 7 deletions(-) diff --git a/drivers/mtd/nand/nand_bbt.c b/drivers/mtd/nand/nand_bbt.c index 45cdb97..7b9a0a7 100644 --- a/drivers/mtd/nand/nand_bbt.c +++ b/drivers/mtd/nand/nand_bbt.c @@ -289,14 +289,24 @@ static int scan_read_data(struct mtd_info *mtd, uint8_t *buf, loff_t offs, return mtd_read(mtd, offs, len, &retlen, buf); } -/* Scan read data from flash */ +/** + * scan_read_oob - [GENERIC] Scan data+OOB region to buffer + * @mtd: MTD device structure + * @buf: temporary buffer + * @offs: offset at which to scan + * @len: length of data region to read + * + * Scan read data from data+OOB. May traverse multiple pages, interleaving + * page,OOB,page,OOB,... in buf. Completes transfer and returns the "strongest" + * ECC condition (error or bitflip). May quit on the first (non-ECC) error. + */ static int scan_read_oob(struct mtd_info *mtd, uint8_t *buf, loff_t offs, size_t len) { struct mtd_oob_ops ops; - int res; + int res, ret = 0; - ops.mode = MTD_OPS_RAW; + ops.mode = MTD_OPS_PLACE_OOB; ops.ooboffs = 0; ops.ooblen = mtd->oobsize; @@ -306,15 +316,18 @@ static int scan_read_oob(struct mtd_info *mtd, uint8_t *buf, loff_t offs, ops.oobbuf = buf + ops.len; res = mtd_read_oob(mtd, offs, &ops); - - if (res) - return res; + if (res) { + if (!mtd_is_bitflip_or_eccerr(res)) + return res; + else if (mtd_is_eccerr(res) || !ret) + ret = res; + } buf += mtd->oobsize + mtd->writesize; len -= mtd->writesize; offs += mtd->writesize; } - return 0; + return ret; } static int scan_read(struct mtd_info *mtd, uint8_t *buf, loff_t offs, -- 1.7.10