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

1 files changed, 4 insertions, 56 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)