[PATCH v2 2/4] mtd: nand: mxc_nand: Cleanup code creating bad block table

[Uwe Kleine-König]

Let the variable "numblocks" contain the number of blocks of the NAND
device (and not twice this value). Also the loop variable counts blocks
now instead of the doubled value. Further calculate the offset of the
i-th block from i instead of incrementing in each step and pick a more
sensbile variable name for it.

Also checkbad() only makes use of *mtd which is already available in the
caller, so pass that one directly. Additionally initialize the struct
mtd_oob_ops in the declarator (which has the nice side effect of zeroing
the members not mentioned) and improve code comments.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig at pengutronix.de>
---
 drivers/mtd/nand/raw/mxc_nand.c | 41 ++++++++++++++++-----------------
 1 file changed, 20 insertions(+), 21 deletions(-)

diff --git a/drivers/mtd/nand/raw/mxc_nand.c b/drivers/mtd/nand/raw/mxc_nand.c
index f7ef2e4374a9..8e564fa76a33 100644
--- a/drivers/mtd/nand/raw/mxc_nand.c
+++ b/drivers/mtd/nand/raw/mxc_nand.c
@@ -1555,19 +1555,18 @@ static const struct nand_controller_ops mxcnd_controller_ops = {
  * From this point on we can forget about the BBMs and rely completely
  * on the flash BBT.
  */
-static int checkbad(struct nand_chip *chip, loff_t ofs)
+static int checkbad(struct mtd_info *mtd, loff_t ofs)
 {
-	struct mtd_info *mtd = nand_to_mtd(chip);
 	int ret;
 	uint8_t buf[mtd->writesize + mtd->oobsize];
-	struct mtd_oob_ops ops;
-
-	ops.mode = MTD_OPS_RAW;
-	ops.ooboffs = 0;
-	ops.datbuf = buf;
-	ops.len = mtd->writesize;
-	ops.oobbuf = buf + mtd->writesize;
-	ops.ooblen = mtd->oobsize;
+	struct mtd_oob_ops ops = {
+		.mode = MTD_OPS_RAW,
+		.ooboffs = 0,
+		.datbuf = buf,
+		.len = mtd->writesize,
+		.oobbuf = buf + mtd->writesize,
+		.ooblen = mtd->oobsize,
+	};
 
 	ret = mtd_read_oob(mtd, ofs, &ops);
 	if (ret < 0)
@@ -1585,31 +1584,31 @@ static int imxnd_create_bbt(struct nand_chip *chip)
 {
 	struct mtd_info *mtd = nand_to_mtd(chip);
 	int len, i, numblocks, ret;
-	loff_t from = 0;
 	uint8_t *bbt;
 
-	len = mtd->size >> (chip->bbt_erase_shift + 2);
+	numblocks = mtd->size >> chip->bbt_erase_shift;
 
-	/* Allocate memory (2bit per block) and clear the memory bad block table */
+	/*
+	 * Allocate memory (2bit per block = 1 byte per 4 blocks) and clear the
+	 * memory bad block table
+	 */
+	len = (numblocks + 3) >> 2;
 	bbt = kzalloc(len, GFP_KERNEL);
 	if (!bbt)
 		return -ENOMEM;
 
-	numblocks = mtd->size >> (chip->bbt_erase_shift - 1);
+	for (i = 0; i < numblocks; ++i) {
+		loff_t ofs = i << chip->bbt_erase_shift;
 
-	for (i = 0; i < numblocks;) {
-		ret = checkbad(chip, from);
+		ret = checkbad(mtd, ofs);
 		if (ret < 0)
 			goto out;
 
 		if (ret) {
-			bbt[i >> 3] |= 0x03 << (i & 0x6);
+			bbt[i >> 2] |= 0x03 << (2 * (i & 0x3));
 			dev_info(mtd->dev.parent, "Bad eraseblock %d at 0x%08x\n",
-				 i >> 1, (unsigned int)from);
+				 i, (unsigned int)ofs);
 		}
-
-		i += 2;
-		from += (1 << chip->bbt_erase_shift);
 	}
 
 	chip->bbt_td->options |= NAND_BBT_CREATE;
-- 
2.43.0