mtd: nand: use read_oob() instead of cmdfunc() for bad block check

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Gitweb:     http://git.infradead.org/?p=mtd-2.6.git;a=commit;h=c120e75e0e7deff88119376298342df139b9b17c
Commit:     c120e75e0e7deff88119376298342df139b9b17c
Parent:     9fe4b66efb77fec71a9c11de58e5e51c5c826190
Author:     Masahiro Yamada <yamada.masahiro at socionext.com>
AuthorDate: Thu Mar 23 05:07:01 2017 +0900
Committer:  Boris Brezillon <boris.brezillon at free-electrons.com>
CommitDate: Fri Mar 24 09:47:43 2017 +0100

    mtd: nand: use read_oob() instead of cmdfunc() for bad block check
    
    The nand_default_block_markbad() and scan_block_fast() use high
    level APIs to get access to the BBM.
    
    On the other hand, nand_block_bad (the default implementation of
    ->block_bad) calls the lower level ->cmdfunc hook.  This prevents
    drivers from using ->ecc.read_oob() even if optimized read operation
    is implemented.  Besides, some NAND controllers may protect the BBM
    with ECC.
    
    Signed-off-by: Masahiro Yamada <yamada.masahiro at socionext.com>
    Signed-off-by: Boris Brezillon <boris.brezillon at free-electrons.com>
---
 drivers/mtd/nand/nand_base.c | 34 +++++++++++++---------------------
 1 file changed, 13 insertions(+), 21 deletions(-)

diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
index d3545c9..afbb80f 100644
--- a/drivers/mtd/nand/nand_base.c
+++ b/drivers/mtd/nand/nand_base.c
@@ -354,40 +354,32 @@ static void nand_read_buf16(struct mtd_info *mtd, uint8_t *buf, int len)
  */
 static int nand_block_bad(struct mtd_info *mtd, loff_t ofs)
 {
-	int page, res = 0, i = 0;
+	int page, page_end, res;
 	struct nand_chip *chip = mtd_to_nand(mtd);
-	u16 bad;
+	u8 bad;
 
 	if (chip->bbt_options & NAND_BBT_SCANLASTPAGE)
 		ofs += mtd->erasesize - mtd->writesize;
 
 	page = (int)(ofs >> chip->page_shift) & chip->pagemask;
+	page_end = page + (chip->bbt_options & NAND_BBT_SCAN2NDPAGE ? 2 : 1);
 
-	do {
-		if (chip->options & NAND_BUSWIDTH_16) {
-			chip->cmdfunc(mtd, NAND_CMD_READOOB,
-					chip->badblockpos & 0xFE, page);
-			bad = cpu_to_le16(chip->read_word(mtd));
-			if (chip->badblockpos & 0x1)
-				bad >>= 8;
-			else
-				bad &= 0xFF;
-		} else {
-			chip->cmdfunc(mtd, NAND_CMD_READOOB, chip->badblockpos,
-					page);
-			bad = chip->read_byte(mtd);
-		}
+	for (; page < page_end; page++) {
+		res = chip->ecc.read_oob(mtd, chip, page);
+		if (res)
+			return res;
+
+		bad = chip->oob_poi[chip->badblockpos];
 
 		if (likely(chip->badblockbits == 8))
 			res = bad != 0xFF;
 		else
 			res = hweight8(bad) < chip->badblockbits;
-		ofs += mtd->writesize;
-		page = (int)(ofs >> chip->page_shift) & chip->pagemask;
-		i++;
-	} while (!res && i < 2 && (chip->bbt_options & NAND_BBT_SCAN2NDPAGE));
+		if (res)
+			return res;
+	}
 
-	return res;
+	return 0;
 }
 
 /**