mtd: Introduce mtd_block_isreserved()

In addition to mtd_block_isbad(), which checks if a block is bad or
reserved, it's needed to check if a block is reserved only (but not
bad). This commit adds an MTD interface for it, in a similar fashion to
mtd_block_isbad().

While here, fix mtd_block_isbad() so the out-of-bounds checking is done
before the callback check.

Signed-off-by: Ezequiel Garcia <[e-mail]>
Tested-by: Pekon Gupta <[e-mail]>
Signed-off-by: Brian Norris <[e-mail]>

drivers/mtd/mtdcore.c

···
 }
 EXPORT_SYMBOL_GPL(mtd_is_locked);
 
-int mtd_block_isbad(struct mtd_info *mtd, loff_t ofs)
+int mtd_block_isreserved(struct mtd_info *mtd, loff_t ofs)
 {
-	if (!mtd->_block_isbad)
-		return 0;
 	if (ofs < 0 || ofs > mtd->size)
 		return -EINVAL;
+	if (!mtd->_block_isreserved)
+		return 0;
+	return mtd->_block_isreserved(mtd, ofs);
+}
+EXPORT_SYMBOL_GPL(mtd_block_isreserved);
+
+int mtd_block_isbad(struct mtd_info *mtd, loff_t ofs)
+{
+	if (ofs < 0 || ofs > mtd->size)
+		return -EINVAL;
+	if (!mtd->_block_isbad)
+		return 0;
 	return mtd->_block_isbad(mtd, ofs);
 }
 EXPORT_SYMBOL_GPL(mtd_block_isbad);

drivers/mtd/mtdpart.c

···
 	part->master->_resume(part->master);
 }
 
+static int part_block_isreserved(struct mtd_info *mtd, loff_t ofs)
+{
+	struct mtd_part *part = PART(mtd);
+	ofs += part->offset;
+	return part->master->_block_isreserved(part->master, ofs);
+}
+
 static int part_block_isbad(struct mtd_info *mtd, loff_t ofs)
 {
 	struct mtd_part *part = PART(mtd);
···
 		slave->mtd._unlock = part_unlock;
 	if (master->_is_locked)
 		slave->mtd._is_locked = part_is_locked;
+	if (master->_block_isreserved)
+		slave->mtd._block_isreserved = part_block_isreserved;
 	if (master->_block_isbad)
 		slave->mtd._block_isbad = part_block_isbad;
 	if (master->_block_markbad)

drivers/mtd/nand/nand_base.c

···
  * nand_block_checkbad - [GENERIC] Check if a block is marked bad
  * @mtd: MTD device structure
  * @ofs: offset from device start
+ *
+ * Check if the block is mark as reserved.
+ */
+static int nand_block_isreserved(struct mtd_info *mtd, loff_t ofs)
+{
+	struct nand_chip *chip = mtd->priv;
+
+	if (!chip->bbt)
+		return 0;
+	/* Return info from the table */
+	return nand_isreserved_bbt(mtd, ofs);
+}
+
+/**
+ * nand_block_checkbad - [GENERIC] Check if a block is marked bad
+ * @mtd: MTD device structure
+ * @ofs: offset from device start
  * @getchip: 0, if the chip is already selected
  * @allowbbt: 1, if its allowed to access the bbt area
  *
···
 	mtd->_unlock = NULL;
 	mtd->_suspend = nand_suspend;
 	mtd->_resume = nand_resume;
+	mtd->_block_isreserved = nand_block_isreserved;
 	mtd->_block_isbad = nand_block_isbad;
 	mtd->_block_markbad = nand_block_markbad;
 	mtd->writebufsize = mtd->writesize;

drivers/mtd/nand/nand_bbt.c

···
 }
 
 /**
+ * nand_isreserved_bbt - [NAND Interface] Check if a block is reserved
+ * @mtd: MTD device structure
+ * @offs: offset in the device
+ */
+int nand_isreserved_bbt(struct mtd_info *mtd, loff_t offs)
+{
+	struct nand_chip *this = mtd->priv;
+	int block;
+
+	block = (int)(offs >> this->bbt_erase_shift);
+	return bbt_get_entry(this, block) == BBT_BLOCK_RESERVED;
+}
+
+/**
  * nand_isbad_bbt - [NAND Interface] Check if a block is bad
  * @mtd: MTD device structure
  * @offs: offset in the device

include/linux/mtd/mtd.h

···
 	int (*_lock) (struct mtd_info *mtd, loff_t ofs, uint64_t len);
 	int (*_unlock) (struct mtd_info *mtd, loff_t ofs, uint64_t len);
 	int (*_is_locked) (struct mtd_info *mtd, loff_t ofs, uint64_t len);
+	int (*_block_isreserved) (struct mtd_info *mtd, loff_t ofs);
 	int (*_block_isbad) (struct mtd_info *mtd, loff_t ofs);
 	int (*_block_markbad) (struct mtd_info *mtd, loff_t ofs);
 	int (*_suspend) (struct mtd_info *mtd);
···
 int mtd_lock(struct mtd_info *mtd, loff_t ofs, uint64_t len);
 int mtd_unlock(struct mtd_info *mtd, loff_t ofs, uint64_t len);
 int mtd_is_locked(struct mtd_info *mtd, loff_t ofs, uint64_t len);
+int mtd_block_isreserved(struct mtd_info *mtd, loff_t ofs);
 int mtd_block_isbad(struct mtd_info *mtd, loff_t ofs);
 int mtd_block_markbad(struct mtd_info *mtd, loff_t ofs);
 

include/linux/mtd/nand.h

···
 extern int nand_scan_bbt(struct mtd_info *mtd, struct nand_bbt_descr *bd);
 extern int nand_default_bbt(struct mtd_info *mtd);
 extern int nand_markbad_bbt(struct mtd_info *mtd, loff_t offs);
+extern int nand_isreserved_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);