mmc: core: new discard feature support at Samsung eMMC v4.41+.

Support discard feature if MID field in the CID register is 0x15, EXT.CSD[192]
(device version) is 5 and Bit 0 in the EXT.CSD[64] is 1. Also removed REQ_SECURE flag
check to avoid kernel hang.

This patch is released from samsung.

Change-Id: I4023a900680e9bca10c40311b09ed077a22617db
(cherry picked from commit 4acc227edfb631d377e14911287c1b73682fc9c2)

Conflicts:
	drivers/mmc/card/block.c

6 files changed, 25 insertions, 58 deletions

diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
index ee16f1102e04..586b4ca4725e 100644
--- a/drivers/mmc/card/block.c
+++ b/drivers/mmc/card/block.c
@@ -703,7 +703,9 @@ static int mmc_blk_issue_discard_rq(struct mmc_queue *mq, struct request *req)
 	from = blk_rq_pos(req);
 	nr = blk_rq_sectors(req);
 
-	if (mmc_can_trim(card))
+	if (mmc_can_discard(card))
+		arg = MMC_DISCARD_ARG;
+	else if (mmc_can_trim(card))
 		arg = MMC_TRIM_ARG;
 	else
 		arg = MMC_ERASE_ARG;
@@ -727,57 +729,6 @@ out:
 	return err ? 0 : 1;
 }
 
-static int mmc_blk_issue_secdiscard_rq(struct mmc_queue *mq,
-				       struct request *req)
-{
-	struct mmc_blk_data *md = mq->data;
-	struct mmc_card *card = md->queue.card;
-	unsigned int from, nr, arg;
-	int err = 0;
-
-	if (!mmc_can_secure_erase_trim(card)) {
-		err = -EOPNOTSUPP;
-		goto out;
-	}
-
-	from = blk_rq_pos(req);
-	nr = blk_rq_sectors(req);
-
-	if (mmc_can_trim(card) && !mmc_erase_group_aligned(card, from, nr))
-		arg = MMC_SECURE_TRIM1_ARG;
-	else
-		arg = MMC_SECURE_ERASE_ARG;
-
-	if (card->quirks & MMC_QUIRK_INAND_CMD38) {
-		err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
-				 INAND_CMD38_ARG_EXT_CSD,
-				 arg == MMC_SECURE_TRIM1_ARG ?
-				 INAND_CMD38_ARG_SECTRIM1 :
-				 INAND_CMD38_ARG_SECERASE,
-				 0);
-		if (err)
-			goto out;
-	}
-	err = mmc_erase(card, from, nr, arg);
-	if (!err && arg == MMC_SECURE_TRIM1_ARG) {
-		if (card->quirks & MMC_QUIRK_INAND_CMD38) {
-			err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
-					 INAND_CMD38_ARG_EXT_CSD,
-					 INAND_CMD38_ARG_SECTRIM2,
-					 0);
-			if (err)
-				goto out;
-		}
-		err = mmc_erase(card, from, nr, MMC_SECURE_TRIM2_ARG);
-	}
-out:
-	spin_lock_irq(&md->lock);
-	__blk_end_request(req, err, blk_rq_bytes(req));
-	spin_unlock_irq(&md->lock);
-
-	return err ? 0 : 1;
-}
-
 static int mmc_blk_issue_flush(struct mmc_queue *mq, struct request *req)
 {
 	struct mmc_blk_data *md = mq->data;
@@ -1222,10 +1173,7 @@ static int mmc_blk_issue_rq(struct mmc_queue *mq, struct request *req)
 		/* complete ongoing async transfer before issuing discard */
 		if (card->host->areq)
 			mmc_blk_issue_rw_rq(mq, NULL);
-		if (req->cmd_flags & REQ_SECURE)
-			ret = mmc_blk_issue_secdiscard_rq(mq, req);
-		else
-			ret = mmc_blk_issue_discard_rq(mq, req);
+		ret = mmc_blk_issue_discard_rq(mq, req);
 	} else if (req && req->cmd_flags & REQ_FLUSH) {
 		/* complete ongoing async transfer before issuing flush */
 		if (card->host->areq)
diff --git a/drivers/mmc/card/queue.c b/drivers/mmc/card/queue.c
index 01c0357656a7..ba38a2fe12f5 100644
--- a/drivers/mmc/card/queue.c
+++ b/drivers/mmc/card/queue.c
@@ -142,7 +142,7 @@ static void mmc_queue_setup_discard(struct request_queue *q,
 
 	queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, q);
 	q->limits.max_discard_sectors = max_discard;
-	if (card->erased_byte == 0)
+	if (card->erased_byte == 0 && !mmc_can_discard(card))
 		q->limits.discard_zeroes_data = 1;
 	q->limits.discard_granularity = card->pref_erase << 9;
 	/* granularity must not be greater than max. discard */
diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index bc200be1b3c0..58a38153db63 100644..100755
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -1579,7 +1579,10 @@ static unsigned int mmc_mmc_erase_timeout(struct mmc_card *card,
 {
 	unsigned int erase_timeout;
 
-	if (card->ext_csd.erase_group_def & 1) {
+	if (arg == MMC_DISCARD_ARG ||
+		(arg == MMC_TRIM_ARG && card->ext_csd.rev >= 6)) {
+		erase_timeout = card->ext_csd.trim_timeout;
+	} else if (card->ext_csd.erase_group_def & 1) {
 		/* High Capacity Erase Group Size uses HC timeouts */
 		if (arg == MMC_TRIM_ARG)
 			erase_timeout = card->ext_csd.trim_timeout;
@@ -1855,6 +1858,14 @@ int mmc_can_trim(struct mmc_card *card)
 }
 EXPORT_SYMBOL(mmc_can_trim);
 
+int mmc_can_discard(struct mmc_card *card)
+{
+	if (card->ext_csd.feature_support & MMC_DISCARD_FEATURE)
+		return 1;
+	return 0;
+}
+EXPORT_SYMBOL( mmc_can_discard);
+
 int mmc_can_secure_erase_trim(struct mmc_card *card)
 {
 	if (card->ext_csd.sec_feature_support & EXT_CSD_SEC_ER_EN)
diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index a5e09b8ee068..9af23fe2ae8f 100644..100755
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -443,6 +443,9 @@ static int mmc_read_ext_csd(struct mmc_card *card, u8 *ext_csd)
 	else
 		card->erased_byte = 0x0;
 
+	if ((card->cid.manfid == 0x15) && (ext_csd[64] & 0x01))
+		card->ext_csd.feature_support |= MMC_DISCARD_FEATURE;
+
 out:
 	return err;
 }
diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h
index 85f17ff14e7e..ff194e553634 100644
--- a/include/linux/mmc/card.h
+++ b/include/linux/mmc/card.h
@@ -88,6 +88,9 @@ struct mmc_ext_csd {
 	__kernel_time_t		last_tv_sec;		/* last time a block was refreshed */
 	__kernel_time_t		last_bkops_tv_sec;	/* last time bkops was done */
 	unsigned int		sec_count;
+
+	unsigned int		feature_support;
+#define MMC_DISCARD_FEATURE	BIT(0)
 };
 
 struct sd_scr {
diff --git a/include/linux/mmc/core.h b/include/linux/mmc/core.h
index 0c4472eff796..921c4f6a2e0e 100644
--- a/include/linux/mmc/core.h
+++ b/include/linux/mmc/core.h
@@ -154,6 +154,7 @@ extern int mmc_switch(struct mmc_card *, u8, u8, u8, unsigned int);
 #define MMC_ERASE_ARG		0x00000000
 #define MMC_SECURE_ERASE_ARG	0x80000000
 #define MMC_TRIM_ARG		0x00000001
+#define MMC_DISCARD_ARG		0x00000003
 #define MMC_SECURE_TRIM1_ARG	0x80000001
 #define MMC_SECURE_TRIM2_ARG	0x80008000
 
@@ -164,6 +165,7 @@ extern int mmc_erase(struct mmc_card *card, unsigned int from, unsigned int nr,
 		     unsigned int arg);
 extern int mmc_can_erase(struct mmc_card *card);
 extern int mmc_can_trim(struct mmc_card *card);
+extern int mmc_can_discard(struct mmc_card *card);
 extern int mmc_can_secure_erase_trim(struct mmc_card *card);
 extern int mmc_erase_group_aligned(struct mmc_card *card, unsigned int from,
 				   unsigned int nr);