mtd: introduce function max_bad_blocks

If implemented, 'max_bad_blocks' returns the maximum number of bad
blocks to reserve for a MTD. An implementation for NAND is coming soon.
Signed-off-by: Jeff Westfahl <jeff.westfahl@ni.com>
Signed-off-by: Zach Brown <zach.brown@ni.com>
Acked-by: Boris Brezillon <boris.brezillon@free-electron.com>
Acked-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

drivers/mtd/mtdpart.c

@@ -349,6 +349,14 @@ static const struct mtd_ooblayout_ops part_ooblayout_ops = {
 	.free = part_ooblayout_free,
 };
 
+static int part_max_bad_blocks(struct mtd_info *mtd, loff_t ofs, size_t len)
+{
+	struct mtd_part *part = mtd_to_part(mtd);
+
+	return part->master->_max_bad_blocks(part->master,
+					     ofs + part->offset, len);
+}
+
 static inline void free_partition(struct mtd_part *p)
 {
 	kfree(p->mtd.name);
@@ -475,6 +483,8 @@ static struct mtd_part *allocate_partition(struct mtd_info *master,
 		slave->mtd._block_isbad = part_block_isbad;
 	if (master->_block_markbad)
 		slave->mtd._block_markbad = part_block_markbad;
+	if (master->_max_bad_blocks)
+		slave->mtd._max_bad_blocks = part_max_bad_blocks;
 
 	if (master->_get_device)
 		slave->mtd._get_device = part_get_device;

include/linux/mtd/mtd.h

@@ -322,6 +322,7 @@ struct mtd_info {
 	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 (*_max_bad_blocks) (struct mtd_info *mtd, loff_t ofs, size_t len);
 	int (*_suspend) (struct mtd_info *mtd);
 	void (*_resume) (struct mtd_info *mtd);
 	void (*_reboot) (struct mtd_info *mtd);
@@ -397,6 +398,18 @@ static inline int mtd_oobavail(struct mtd_info *mtd, struct mtd_oob_ops *ops)
 	return ops->mode == MTD_OPS_AUTO_OOB ? mtd->oobavail : mtd->oobsize;
 }
 
+static inline int mtd_max_bad_blocks(struct mtd_info *mtd,
+				     loff_t ofs, size_t len)
+{
+	if (!mtd->_max_bad_blocks)
+		return -ENOTSUPP;
+
+	if (mtd->size < (len + ofs) || ofs < 0)
+		return -EINVAL;
+
+	return mtd->_max_bad_blocks(mtd, ofs, len);
+}
+
 int mtd_wunit_to_pairing_info(struct mtd_info *mtd, int wunit,
 			      struct mtd_pairing_info *info);
 int mtd_pairing_info_to_wunit(struct mtd_info *mtd,