[PATCH v1 2/3] mmc: block: Add mmc_bdev_to_card() helper

[Dmitry Osipenko <digetx@gmail.com>]

NVIDIA Tegra Partition Table takes into account MMC card's BOOT_SIZE_MULT
parameter, and thus, the partition parser needs to retrieve that EXT_CSD
value from the block device. This patch introduces new helper which takes
block device for the input argument and returns corresponding MMC card.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/mmc/core/block.c | 14 ++++++++++++++
 include/linux/mmc/card.h |  3 +++
 2 files changed, 17 insertions(+)

diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c
index 663d87924e5e..5d853450c764 100644
--- a/drivers/mmc/core/block.c
+++ b/drivers/mmc/core/block.c
@@ -301,6 +301,20 @@ static ssize_t force_ro_store(struct device *dev, struct device_attribute *attr,
 	return ret;
 }
 
+struct mmc_card *mmc_bdev_to_card(struct block_device *bdev)
+{
+	struct mmc_blk_data *md;
+
+	if (bdev->bd_disk->major != MMC_BLOCK_MAJOR)
+		return NULL;
+
+	md = mmc_blk_get(bdev->bd_disk);
+	if (!md)
+		return NULL;
+
+	return md->queue.card;
+}
+
 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/card.h b/include/linux/mmc/card.h
index 90b1d83ce675..daccb0cc25f8 100644
--- a/include/linux/mmc/card.h
+++ b/include/linux/mmc/card.h
@@ -7,6 +7,7 @@
 #ifndef LINUX_MMC_CARD_H
 #define LINUX_MMC_CARD_H
 
+#include <linux/blkdev.h>
 #include <linux/device.h>
 #include <linux/mod_devicetable.h>
 
@@ -324,4 +325,6 @@ bool mmc_card_is_blockaddr(struct mmc_card *card);
 #define mmc_card_sd(c)		((c)->type == MMC_TYPE_SD)
 #define mmc_card_sdio(c)	((c)->type == MMC_TYPE_SDIO)
 
+struct mmc_card *mmc_bdev_to_card(struct block_device *bdev);
+
 #endif /* LINUX_MMC_CARD_H */
-- 
2.24.0