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

[Dmitry Osipenko <digetx@gmail.com>]

Add mmc_bdev_to_card() helper which is needed for finding EFI entry
on EMMC of NVIDIA Tegra devices.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/mmc/core/block.c   | 15 +++++++++++++++
 include/linux/mmc/blkdev.h | 13 +++++++++++++
 2 files changed, 28 insertions(+)
 create mode 100644 include/linux/mmc/blkdev.h

diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c
index fe5892d30778..666066fd6037 100644
--- a/drivers/mmc/core/block.c
+++ b/drivers/mmc/core/block.c
@@ -40,6 +40,7 @@
 #include <linux/debugfs.h>
 
 #include <linux/mmc/ioctl.h>
+#include <linux/mmc/blkdev.h>
 #include <linux/mmc/card.h>
 #include <linux/mmc/host.h>
 #include <linux/mmc/mmc.h>
@@ -306,6 +307,20 @@ 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/blkdev.h b/include/linux/mmc/blkdev.h
new file mode 100644
index 000000000000..67608c58de70
--- /dev/null
+++ b/include/linux/mmc/blkdev.h
@@ -0,0 +1,13 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ *  linux/include/linux/mmc/blkdev.h
+ */
+#ifndef LINUX_MMC_BLOCK_DEVICE_H
+#define LINUX_MMC_BLOCK_DEVICE_H
+
+struct block_device;
+struct mmc_card;
+
+struct mmc_card *mmc_bdev_to_card(struct block_device *bdev);
+
+#endif /* LINUX_MMC_BLOCK_DEVICE_H */
-- 
2.30.2