mtd: mtdparts: introduce mtd_get_device_size

'mtd_get_device_size()' returns the size of the whole MTD device, that is the
mtd_info master size. This will be used by UBI to calculate the maximum number
of bad blocks (MBB) on a MTD device.

Artem: amended the patch a bit.
Signed-off-by: Richard Genoud <richard.genoud@gmail.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>

drivers/mtd/mtdpart.c

@@ -760,3 +760,13 @@ int mtd_is_partition(const struct mtd_info *mtd)
 	return ispart;
 }
 EXPORT_SYMBOL_GPL(mtd_is_partition);
+
+/* Returns the size of the entire flash chip */
+uint64_t mtd_get_device_size(const struct mtd_info *mtd)
+{
+	if (!mtd_is_partition(mtd))
+		return mtd->size;
+
+	return PART(mtd)->master->size;
+}
+EXPORT_SYMBOL_GPL(mtd_get_device_size);

include/linux/mtd/partitions.h

@@ -83,5 +83,6 @@ int mtd_is_partition(const struct mtd_info *mtd);
 int mtd_add_partition(struct mtd_info *master, char *name,
 		      long long offset, long long length);
 int mtd_del_partition(struct mtd_info *master, int partno);
+uint64_t mtd_get_device_size(const struct mtd_info *mtd);
 
 #endif