[PATCH 3/4] mtd: nand: hide in-memory BBT implementation details

[Brian Norris]

nand_base.c shouldn't have to know the implementation details of
nand_bbt's in-memory BBT. Specifically, nand_base shouldn't perform the
bit masking and shifting to isolate a BBT entry.

Instead, just move some of the BBT code into a new nand_markbad_bbt()
interface. This interface allows external users (i.e., nand_base) to
mark a single block as bad in the BBT. Then nand_bbt will take care of
modifying the in-memory BBT and updating the flash-based BBT (if
applicable).

Signed-off-by: Brian Norris <computersforpeace at gmail.com>
---
 drivers/mtd/nand/nand_base.c | 32 +++++++++++---------------------
 drivers/mtd/nand/nand_bbt.c  | 28 ++++++++++++++++++++++++++--
 include/linux/mtd/nand.h     |  2 +-
 3 files changed, 38 insertions(+), 24 deletions(-)

diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
index a9119f7..da3ba77 100644
--- a/drivers/mtd/nand/nand_base.c
+++ b/drivers/mtd/nand/nand_base.c
@@ -374,22 +374,20 @@ static int nand_default_block_markbad(struct mtd_info *mtd, loff_t ofs)
  * block table(s) and/or marker(s)). We only allow the hardware driver to
  * specify how to write bad block markers to OOB (chip->block_markbad).
  *
- * We try operations in the following order, according to our bbt_options
- * (NAND_BBT_NO_OOB_BBM and NAND_BBT_USE_FLASH):
+ * We try operations in the following order:
  *  (1) erase the affected block, to allow OOB marker to be written cleanly
- *  (2) update in-memory BBT
- *  (3) write bad block marker to OOB area of affected block
- *  (4) update flash-based BBT
- * Note that we retain the first error encountered in (3) or (4), finish the
+ *  (2) write bad block marker to OOB area of affected block (unless flag
+ *      NAND_BBT_NO_OOB_BBM is present)
+ *  (3) update the BBT
+ * Note that we retain the first error encountered in (2) or (3), finish the
  * procedures, and dump the error in the end.
 */
 static int nand_block_markbad_lowlevel(struct mtd_info *mtd, loff_t ofs)
 {
 	struct nand_chip *chip = mtd->priv;
-	int block, res, ret = 0;
-	int write_oob = !(chip->bbt_options & NAND_BBT_NO_OOB_BBM);
+	int res, ret = 0;
 
-	if (write_oob) {
+	if (!(chip->bbt_options & NAND_BBT_NO_OOB_BBM)) {
 		struct erase_info einfo;
 
 		/* Attempt erase before marking OOB */
@@ -398,24 +396,16 @@ static int nand_block_markbad_lowlevel(struct mtd_info *mtd, loff_t ofs)
 		einfo.addr = ofs;
 		einfo.len = 1 << chip->phys_erase_shift;
 		nand_erase_nand(mtd, &einfo, 0);
-	}
-
-	/* Get block number */
-	block = (int)(ofs >> chip->bbt_erase_shift);
-	/* Mark block bad in memory-based BBT */
-	if (chip->bbt)
-		chip->bbt[block >> 2] |= 0x01 << ((block & 0x03) << 1);
 
-	/* Write bad block marker to OOB */
-	if (write_oob) {
+		/* Write bad block marker to OOB */
 		nand_get_device(mtd, FL_WRITING);
 		ret = chip->block_markbad(mtd, ofs);
 		nand_release_device(mtd);
 	}
 
-	/* Update flash-based bad block table */
-	if (chip->bbt_options & NAND_BBT_USE_FLASH) {
-		res = nand_update_bbt(mtd, ofs);
+	/* Mark block bad in BBT */
+	if (chip->bbt) {
+		res = nand_markbad_bbt(mtd, ofs);
 		if (!ret)
 			ret = res;
 	}
diff --git a/drivers/mtd/nand/nand_bbt.c b/drivers/mtd/nand/nand_bbt.c
index bac481a..ae3fb58 100644
--- a/drivers/mtd/nand/nand_bbt.c
+++ b/drivers/mtd/nand/nand_bbt.c
@@ -79,6 +79,8 @@
 #define BBT_ENTRY_MASK		0x03
 #define BBT_ENTRY_SHIFT		2
 
+static int nand_update_bbt(struct mtd_info *mtd, loff_t offs);
+
 static inline uint8_t bbt_get_entry(struct nand_chip *chip, int block)
 {
 	uint8_t entry = chip->bbt[block >> BBT_ENTRY_SHIFT];
@@ -1194,13 +1196,13 @@ int nand_scan_bbt(struct mtd_info *mtd, struct nand_bbt_descr *bd)
 }
 
 /**
- * nand_update_bbt - [NAND Interface] update bad block table(s)
+ * nand_update_bbt - update bad block table(s)
  * @mtd: MTD device structure
  * @offs: the offset of the newly marked block
  *
  * The function updates the bad block table(s).
  */
-int nand_update_bbt(struct mtd_info *mtd, loff_t offs)
+static int nand_update_bbt(struct mtd_info *mtd, loff_t offs)
 {
 	struct nand_chip *this = mtd->priv;
 	int len, res = 0;
@@ -1390,5 +1392,27 @@ int nand_isbad_bbt(struct mtd_info *mtd, loff_t offs, int allowbbt)
 	return 1;
 }
 
+/**
+ * nand_markbad_bbt - [NAND Interface] Mark a block bad in the BBT
+ * @mtd: MTD device structure
+ * @offs: offset of the bad block
+ */
+int nand_markbad_bbt(struct mtd_info *mtd, loff_t offs)
+{
+	struct nand_chip *this = mtd->priv;
+	int block, ret = 0;
+
+	block = (int)(offs >> this->bbt_erase_shift);
+
+	/* Mark bad block in memory */
+	bbt_mark_entry(this, block, BBT_BLOCK_WORN);
+
+	/* Update flash-based bad block table */
+	if (this->bbt_options & NAND_BBT_USE_FLASH)
+		ret = nand_update_bbt(mtd, offs);
+
+	return ret;
+}
+
 EXPORT_SYMBOL(nand_scan_bbt);
 EXPORT_SYMBOL(nand_default_bbt);
diff --git a/include/linux/mtd/nand.h b/include/linux/mtd/nand.h
index 0745a42..9f7b248 100644
--- a/include/linux/mtd/nand.h
+++ b/include/linux/mtd/nand.h
@@ -628,8 +628,8 @@ extern struct nand_flash_dev nand_flash_ids[];
 extern struct nand_manufacturers nand_manuf_ids[];
 
 extern int nand_scan_bbt(struct mtd_info *mtd, struct nand_bbt_descr *bd);
-extern int nand_update_bbt(struct mtd_info *mtd, loff_t offs);
 extern int nand_default_bbt(struct mtd_info *mtd);
+extern int nand_markbad_bbt(struct mtd_info *mtd, loff_t offs);
 extern int nand_isbad_bbt(struct mtd_info *mtd, loff_t offs, int allowbbt);
 extern int nand_erase_nand(struct mtd_info *mtd, struct erase_info *instr,
 			   int allowbbt);
-- 
1.8.3.2