[PATCH v5 2/5] mmc: block: Support alternative_gpt_sector() operation

[Dmitry Osipenko <digetx@gmail.com>]

Support generic alternative_gpt_sector() block device operation by
invoking a new platform-specific MMC host hook that is also named
alternative_gpt_sector().

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/mmc/core/block.c | 30 ++++++++++++++++++++++++++++++
 include/linux/mmc/host.h |  4 ++++
 2 files changed, 34 insertions(+)

diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c
index 672cc505ce37..8ad1841f0dbd 100644
--- a/drivers/mmc/core/block.c
+++ b/drivers/mmc/core/block.c
@@ -178,6 +178,7 @@ static void mmc_blk_rw_rq_prep(struct mmc_queue_req *mqrq,
 			       int disable_multi,
 			       struct mmc_queue *mq);
 static void mmc_blk_hsq_req_done(struct mmc_request *mrq);
+static struct mmc_card *mmc_bdev_to_card(struct block_device *bdev);
 
 static struct mmc_blk_data *mmc_blk_get(struct gendisk *disk)
 {
@@ -801,6 +802,20 @@ static int mmc_blk_compat_ioctl(struct block_device *bdev, fmode_t mode,
 }
 #endif
 
+static int mmc_blk_alternative_gpt_sector(struct block_device *bdev,
+					  sector_t *sector)
+{
+	struct mmc_card *card = mmc_bdev_to_card(bdev);
+
+	if (!card)
+		return -ENODEV;
+
+	if (!card->host->ops->alternative_gpt_sector)
+		return -EOPNOTSUPP;
+
+	return card->host->ops->alternative_gpt_sector(card, sector);
+}
+
 static const struct block_device_operations mmc_bdops = {
 	.open			= mmc_blk_open,
 	.release		= mmc_blk_release,
@@ -810,8 +825,23 @@ static const struct block_device_operations mmc_bdops = {
 #ifdef CONFIG_COMPAT
 	.compat_ioctl		= mmc_blk_compat_ioctl,
 #endif
+	.alternative_gpt_sector	= mmc_blk_alternative_gpt_sector,
 };
 
+static struct mmc_card *mmc_bdev_to_card(struct block_device *bdev)
+{
+	struct mmc_blk_data *md;
+
+	if (bdev->bd_disk->fops != &mmc_bdops)
+		return NULL;
+
+	md = mmc_blk_get(bdev->bd_disk);
+	if (!md)
+		return NULL;
+
+	return md->queue.card;
+}
+
 static int mmc_blk_part_switch_pre(struct mmc_card *card,
 				   unsigned int part_type)
 {
diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
index 0abd47e9ef9b..18281c444bf6 100644
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -190,6 +190,10 @@ struct mmc_host_ops {
 
 	/* Initialize an SD express card, mandatory for MMC_CAP2_SD_EXP. */
 	int	(*init_sd_express)(struct mmc_host *host, struct mmc_ios *ios);
+
+	/* Get platform-specific GPT entry location */
+	int	(*alternative_gpt_sector)(struct mmc_card *card,
+					  sector_t *sector);
 };
 
 struct mmc_cqe_ops {
-- 
2.32.0