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 <ezequiel.garcia@free-electrons.com>
Tested-by: Pekon Gupta <pekon@ti.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

4 files changed, 53 insertions, 2 deletions

diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c
index 11857faa0d96..e4831b4159db 100644
--- a/drivers/mtd/mtdcore.c
+++ b/drivers/mtd/mtdcore.c
@@ -1043,12 +1043,22 @@ int mtd_is_locked(struct mtd_info *mtd, loff_t ofs, uint64_t len)
 }
 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)
+        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);
diff --git a/drivers/mtd/mtdpart.c b/drivers/mtd/mtdpart.c
index 1ca9aec141ff..921e8c647884 100644
--- a/drivers/mtd/mtdpart.c
+++ b/drivers/mtd/mtdpart.c
@@ -290,6 +290,13 @@ static void part_resume(struct mtd_info *mtd)
         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);
@@ -422,6 +429,8 @@ static struct mtd_part *allocate_partition(struct mtd_info *master,
                 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)
diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
index 41167e9e991e..0c505dd1f522 100644
--- a/drivers/mtd/nand/nand_base.c
+++ b/drivers/mtd/nand/nand_base.c
@@ -488,6 +488,23 @@ static int nand_check_wp(struct mtd_info *mtd)
  * 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
  *
@@ -4111,6 +4128,7 @@ int nand_scan_tail(struct mtd_info *mtd)
         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;
diff --git a/drivers/mtd/nand/nand_bbt.c b/drivers/mtd/nand/nand_bbt.c
index 7f0c3b4c2a4f..443fa82cde6a 100644
--- a/drivers/mtd/nand/nand_bbt.c
+++ b/drivers/mtd/nand/nand_bbt.c
@@ -1311,6 +1311,20 @@ int nand_default_bbt(struct mtd_info *mtd)
 }
 
 /**
+ * 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