[PATCH v2 2/4] mtd: rawnand: Support bad block markers in first, second or last page

[Schrempf Frieder <frieder.schrempf@xxxxxxxxxx>]

From: Frieder Schrempf <frieder.schrempf@xxxxxxxxxx>

Currently supported bad block marker positions within the block are:
* in first page only
* in last page only
* in first or second page

Some ESMT NANDs are known to have been shipped by the manufacturer
with bad block markers in the first or last page, instead of the
first or second page.

Also the datasheets for Cypress/Spansion/AMD NANDs claim that the
first, second *and* last page needs to be checked.

Therefore we make it possible to set NAND_BBM_FIRSTPAGE,
NAND_BBM_SECONDPAGE and NAND_BBM_LASTPAGE independently in any
combination.

To simplify the code, the logic to evaluate the flags is moved to a
a new function nand_bbm_get_next_page().

Signed-off-by: Frieder Schrempf <frieder.schrempf@xxxxxxxxxx>
---
 drivers/mtd/nand/raw/internals.h |  1 +
 drivers/mtd/nand/raw/nand_base.c | 62 ++++++++++++++++++++++++-----------
 drivers/mtd/nand/raw/nand_bbt.c  | 29 +++++++---------
 3 files changed, 55 insertions(+), 37 deletions(-)

diff --git a/drivers/mtd/nand/raw/internals.h b/drivers/mtd/nand/raw/internals.h
index fbf6ca015cd7..97ae67e009d5 100644
--- a/drivers/mtd/nand/raw/internals.h
+++ b/drivers/mtd/nand/raw/internals.h
@@ -76,6 +76,7 @@ extern const struct nand_manufacturer_ops toshiba_nand_manuf_ops;
 
 /* Core functions */
 const struct nand_manufacturer *nand_get_manufacturer(u8 id);
+int nand_bbm_get_next_page(struct nand_chip *chip, int page);
 int nand_markbad_bbm(struct nand_chip *chip, loff_t ofs);
 int nand_erase_nand(struct nand_chip *chip, struct erase_info *instr,
 		    int allowbbt);
diff --git a/drivers/mtd/nand/raw/nand_base.c b/drivers/mtd/nand/raw/nand_base.c
index 9ef7b86cdc42..7bc20c1fe23c 100644
--- a/drivers/mtd/nand/raw/nand_base.c
+++ b/drivers/mtd/nand/raw/nand_base.c
@@ -285,6 +285,31 @@ static void nand_release_device(struct nand_chip *chip)
 	spin_unlock(&chip->controller->lock);
 }
 
+/**
+ * nand_bbm_get_next_page - Get the next page for bad block markers
+ * @chip: NAND chip object
+ * @index: Current page, only pages beyond this will be considered
+ *
+ * Returns an integer that corresponds to the page offset within a block, for
+ * a page that is used to store bad block markers. If no more pages are
+ * available, -1 is returned.
+ */
+int nand_bbm_get_next_page(struct nand_chip *chip, int page)
+{
+	struct mtd_info *mtd = nand_to_mtd(chip);
+	int last_page = ((mtd->erasesize - mtd->writesize) >>
+			 chip->page_shift) & chip->pagemask;
+
+	if (page < 0 && chip->options & NAND_BBM_FIRSTPAGE)
+		return 0;
+	else if (page < 1 && chip->options & NAND_BBM_SECONDPAGE)
+		return 1;
+	else if (page < last_page && chip->options & NAND_BBM_LASTPAGE)
+		return last_page;
+
+	return -1;
+}
+
 /**
  * nand_block_bad - [DEFAULT] Read bad block marker from the chip
  * @chip: NAND chip object
@@ -294,19 +319,14 @@ static void nand_release_device(struct nand_chip *chip)
  */
 static int nand_block_bad(struct nand_chip *chip, loff_t ofs)
 {
-	struct mtd_info *mtd = nand_to_mtd(chip);
-	int page, page_end, res;
+	int page_offset;
+	int res, first_page = (int)(ofs >> chip->page_shift) & chip->pagemask;
 	u8 bad;
 
-	if (chip->options & NAND_BBM_LASTPAGE)
-		ofs += mtd->erasesize - mtd->writesize;
+	page_offset = nand_bbm_get_next_page(chip, -1);
 
-	page = (int)(ofs >> chip->page_shift) & chip->pagemask;
-	page_end = page + (((chip->options & NAND_BBM_FIRSTPAGE) &&
-			    (chip->options & NAND_BBM_SECONDPAGE)) ? 2 : 1);
-
-	for (; page < page_end; page++) {
-		res = chip->ecc.read_oob(chip, page);
+	while (page_offset != -1) {
+		res = chip->ecc.read_oob(chip, first_page + page_offset);
 		if (res < 0)
 			return res;
 
@@ -318,6 +338,8 @@ static int nand_block_bad(struct nand_chip *chip, loff_t ofs)
 			res = hweight8(bad) < chip->badblockbits;
 		if (res)
 			return res;
+
+		page_offset = nand_bbm_get_next_page(chip, page_offset);
 	}
 
 	return 0;
@@ -528,7 +550,7 @@ static int nand_default_block_markbad(struct nand_chip *chip, loff_t ofs)
 	struct mtd_info *mtd = nand_to_mtd(chip);
 	struct mtd_oob_ops ops;
 	uint8_t buf[2] = { 0, 0 };
-	int ret = 0, res, i = 0;
+	int ret = 0, res, page_offset;
 
 	memset(&ops, 0, sizeof(ops));
 	ops.oobbuf = buf;
@@ -541,18 +563,18 @@ static int nand_default_block_markbad(struct nand_chip *chip, loff_t ofs)
 	}
 	ops.mode = MTD_OPS_PLACE_OOB;
 
-	/* Write to first/last page(s) if necessary */
-	if (chip->options & NAND_BBM_LASTPAGE)
-		ofs += mtd->erasesize - mtd->writesize;
-	do {
-		res = nand_do_write_oob(chip, ofs, &ops);
+	page_offset = nand_bbm_get_next_page(chip, -1);
+
+	while (page_offset != -1) {
+		res = nand_do_write_oob(chip,
+					ofs + page_offset * mtd->writesize,
+					&ops);
+
 		if (!ret)
 			ret = res;
 
-		i++;
-		ofs += mtd->writesize;
-	} while ((chip->options & NAND_BBM_FIRSTPAGE) &&
-		 (chip->options & NAND_BBM_SECONDPAGE) && i < 2);
+		page_offset = nand_bbm_get_next_page(chip, page_offset);
+	}
 
 	return ret;
 }
diff --git a/drivers/mtd/nand/raw/nand_bbt.c b/drivers/mtd/nand/raw/nand_bbt.c
index c095c04d566d..09603c502931 100644
--- a/drivers/mtd/nand/raw/nand_bbt.c
+++ b/drivers/mtd/nand/raw/nand_bbt.c
@@ -415,11 +415,12 @@ static void read_abs_bbts(struct nand_chip *this, uint8_t *buf,
 
 /* Scan a given block partially */
 static int scan_block_fast(struct nand_chip *this, struct nand_bbt_descr *bd,
-			   loff_t offs, uint8_t *buf, int numpages)
+			   loff_t offs, uint8_t *buf)
 {
 	struct mtd_info *mtd = nand_to_mtd(this);
+
 	struct mtd_oob_ops ops;
-	int j, ret;
+	int ret, page_offset;
 
 	ops.ooblen = mtd->oobsize;
 	ops.oobbuf = buf;
@@ -427,12 +428,15 @@ static int scan_block_fast(struct nand_chip *this, struct nand_bbt_descr *bd,
 	ops.datbuf = NULL;
 	ops.mode = MTD_OPS_PLACE_OOB;
 
-	for (j = 0; j < numpages; j++) {
+	page_offset = nand_bbm_get_next_page(this, -1);
+
+	while (page_offset != -1) {
 		/*
 		 * Read the full oob until read_oob is fixed to handle single
 		 * byte reads for 16 bit buswidth.
 		 */
-		ret = mtd_read_oob(mtd, offs, &ops);
+		ret = mtd_read_oob(mtd, offs + page_offset * mtd->writesize,
+				   &ops);
 		/* Ignore ECC errors when checking for BBM */
 		if (ret && !mtd_is_bitflip_or_eccerr(ret))
 			return ret;
@@ -440,8 +444,9 @@ static int scan_block_fast(struct nand_chip *this, struct nand_bbt_descr *bd,
 		if (check_short_pattern(buf, bd))
 			return 1;
 
-		offs += mtd->writesize;
+		page_offset = nand_bbm_get_next_page(this, page_offset);
 	}
+
 	return 0;
 }
 
@@ -460,18 +465,11 @@ static int create_bbt(struct nand_chip *this, uint8_t *buf,
 		      struct nand_bbt_descr *bd, int chip)
 {
 	struct mtd_info *mtd = nand_to_mtd(this);
-	int i, numblocks, numpages;
-	int startblock;
+	int i, numblocks, startblock;
 	loff_t from;
 
 	pr_info("Scanning device for bad blocks\n");
 
-	if ((this->options & NAND_BBM_FIRSTPAGE) &&
-	    (this->options & NAND_BBM_SECONDPAGE))
-		numpages = 2;
-	else
-		numpages = 1;
-
 	if (chip == -1) {
 		numblocks = mtd->size >> this->bbt_erase_shift;
 		startblock = 0;
@@ -488,15 +486,12 @@ static int create_bbt(struct nand_chip *this, uint8_t *buf,
 		from = (loff_t)startblock << this->bbt_erase_shift;
 	}
 
-	if (this->bbt_options & NAND_BBM_LASTPAGE)
-		from += mtd->erasesize - (mtd->writesize * numpages);
-
 	for (i = startblock; i < numblocks; i++) {
 		int ret;
 
 		BUG_ON(bd->options & NAND_BBT_NO_OOB);
 
-		ret = scan_block_fast(this, bd, from, buf, numpages);
+		ret = scan_block_fast(this, bd, from, buf);
 		if (ret < 0)
 			return ret;
 
-- 
2.17.1

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