Support generic alternative_gpt_sector() block device operation which
calculates custom GPT location. Add new MMC_CAP2_ALTERNATIVE_GPT_SECTOR
flag that enables scanning of the alternative sector.
Signed-off-by: Dmitry Osipenko <digetx@xxxxxxxxx>
---
drivers/mmc/core/block.c | 21 +++++++++++++++++++++
drivers/mmc/core/core.c | 35 +++++++++++++++++++++++++++++++++++
drivers/mmc/core/core.h | 2 ++
include/linux/mmc/host.h | 1 +
4 files changed, 59 insertions(+)
diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c
index 672cc505ce37..edd26164be06 100644
--- a/drivers/mmc/core/block.c
+++ b/drivers/mmc/core/block.c
@@ -801,6 +801,26 @@ static int mmc_blk_compat_ioctl(struct block_device *bdev, fmode_t mode,
}
#endif
+static int mmc_blk_alternative_gpt_sector(struct gendisk *disk,
+ sector_t *sector)
+{
+ struct mmc_blk_data *md;
+ int ret;
+
+ md = mmc_blk_get(disk);
+ if (!md)
+ return -EINVAL;
+
+ if (md->queue.card)
+ ret = mmc_card_alternative_gpt_sector(md->queue.card, sector);
+ else
+ ret = -ENODEV;
+
+ mmc_blk_put(md);
+
+ return ret;
+}
+
static const struct block_device_operations mmc_bdops = {
.open = mmc_blk_open,
.release = mmc_blk_release,
@@ -810,6 +830,7 @@ 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 int mmc_blk_part_switch_pre(struct mmc_card *card,
diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index 6249c83d616f..c5cdd56051cb 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -2150,6 +2150,41 @@ int mmc_detect_card_removed(struct mmc_host *host)
}
EXPORT_SYMBOL(mmc_detect_card_removed);
+int mmc_card_alternative_gpt_sector(struct mmc_card *card, sector_t *gpt_sector)
+{
+ unsigned int boot_sectors_num;
+
+ if ((!(card->host->caps2 & MMC_CAP2_ALT_GPT_SECTOR)))
+ return -EOPNOTSUPP;
+
+ /* filter out unrelated cards */
+ if (card->ext_csd.rev < 3 ||
+ !mmc_card_mmc(card) ||
+ !mmc_card_is_blockaddr(card) ||
+ mmc_card_is_removable(card->host))
+ return -ENOENT;
+
+ /*
+ * eMMC storage has two special boot partitions in addition to the
+ * main one. NVIDIA's bootloader linearizes eMMC boot0->boot1->main
+ * accesses, this means that the partition table addresses are shifted
+ * by the size of boot partitions. In accordance with the eMMC
+ * specification, the boot partition size is calculated as follows:
+ *
+ * boot partition size = 128K byte x BOOT_SIZE_MULT
+ *
+ * Calculate number of sectors occupied by the both boot partitions.
+ */
+ boot_sectors_num = card->ext_csd.raw_boot_mult * SZ_128K /
+ SZ_512 * MMC_NUM_BOOT_PARTITION;
+
+ /* Defined by NVIDIA and used by Android devices. */
+ *gpt_sector = card->ext_csd.sectors - boot_sectors_num - 1;
+
+ return 0;
+}
+EXPORT_SYMBOL(mmc_card_alternative_gpt_sector);
+
void mmc_rescan(struct work_struct *work)
{
struct mmc_host *host =
diff --git a/drivers/mmc/core/core.h b/drivers/mmc/core/core.h
index 0c4de2030b3f..7931a4f0137d 100644
--- a/drivers/mmc/core/core.h
+++ b/drivers/mmc/core/core.h
@@ -119,6 +119,8 @@ void mmc_release_host(struct mmc_host *host);
void mmc_get_card(struct mmc_card *card, struct mmc_ctx *ctx);
void mmc_put_card(struct mmc_card *card, struct mmc_ctx *ctx);
+int mmc_card_alternative_gpt_sector(struct mmc_card *card, sector_t *sector);
+
/**
* mmc_claim_host - exclusively claim a host
* @host: mmc host to claim
diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
index 0abd47e9ef9b..73a4cc063bb0 100644
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -398,6 +398,7 @@ struct mmc_host {
#else
#define MMC_CAP2_CRYPTO 0
#endif
+#define MMC_CAP2_ALT_GPT_SECTOR (1 << 28) /* Host with eMMC card that has GPT entry at a non-standard location */
int fixed_drv_type; /* fixed driver type for non-removable media */
--
2.32.0
