[PATCH v2 02/53] mtd: nand: use read_oob() instead of cmdfunc() for bad block check

Masahiro Yamada
2017-03-22T14:09:25Z

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@socionext.com>
---

Changes in v2:
- Error out immediately if the first page access fails
- Use for() {} instead of do {} while()
- Update git-log

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 a3c0f47..807398d 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;
}

/**
--
2.7.4