[PATCH v2 4/8] mmc: block: Add mmc_bdev_to_part_type() helper

[Dmitry Osipenko <digetx@gmail.com>]

NVIDIA Tegra Partition Table parser needs to know eMMC boot partition ID
that is associated with the block device in order to validate and parse
partition table properly. This patch adds new mmc_bdev_to_part_type()
helper which takes block device for the input and returns a corresponding
MMC card partition ID (part_type).

This is needed by tegra-partition parser in order to distinguish boot0
eMMC partition from boot1.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/mmc/core/block.c   | 16 ++++++++++++++++
 include/linux/mmc/blkdev.h |  1 +
 2 files changed, 17 insertions(+)

diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c
index 36d84a8e182c..2cee57c7388d 100644
--- a/drivers/mmc/core/block.c
+++ b/drivers/mmc/core/block.c
@@ -321,6 +321,22 @@ struct mmc_card *mmc_bdev_to_card(struct block_device *bdev)
 	return md->queue.card;
 }
 
+int mmc_bdev_to_part_type(struct block_device *bdev)
+{
+	struct mmc_blk_data *md;
+	struct mmc_card *card;
+
+	card = mmc_bdev_to_card(bdev);
+	if (!card)
+		return -EINVAL;
+
+	md = mmc_blk_get(bdev->bd_disk);
+	if (!md)
+		return -EINVAL;
+
+	return md->part_type;
+}
+
 static int mmc_blk_open(struct block_device *bdev, fmode_t mode)
 {
 	struct mmc_blk_data *md = mmc_blk_get(bdev->bd_disk);
diff --git a/include/linux/mmc/blkdev.h b/include/linux/mmc/blkdev.h
index 67608c58de70..24e73ac02b4b 100644
--- a/include/linux/mmc/blkdev.h
+++ b/include/linux/mmc/blkdev.h
@@ -9,5 +9,6 @@ struct block_device;
 struct mmc_card;
 
 struct mmc_card *mmc_bdev_to_card(struct block_device *bdev);
+int mmc_bdev_to_part_type(struct block_device *bdev);
 
 #endif /* LINUX_MMC_BLOCK_DEVICE_H */
-- 
2.25.1