mmc: block: Prepare CQE data

Enhance mmc_blk_data_prep() to support CQE requests. That means adding
some things that for non-CQE requests would be encoded into the command
arguments - such as the block address, reliable-write flag, and data tag
flag. Also the request tag is needed to provide the command queue task id,
and a comment is added to explain the future possibility of defining a
priority.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

drivers/mmc/core/block.c

@@ -1595,6 +1595,7 @@ static void mmc_blk_data_prep(struct mmc_queue *mq, struct mmc_queue_req *mqrq,
 	memset(brq, 0, sizeof(struct mmc_blk_request));
 
 	brq->mrq.data = &brq->data;
+	brq->mrq.tag = req->tag;
 
 	brq->stop.opcode = MMC_STOP_TRANSMISSION;
 	brq->stop.arg = 0;
@@ -1609,6 +1610,14 @@ static void mmc_blk_data_prep(struct mmc_queue *mq, struct mmc_queue_req *mqrq,
 
 	brq->data.blksz = 512;
 	brq->data.blocks = blk_rq_sectors(req);
+	brq->data.blk_addr = blk_rq_pos(req);
+
+	/*
+	 * The command queue supports 2 priorities: "high" (1) and "simple" (0).
+	 * The eMMC will give "high" priority tasks priority over "simple"
+	 * priority tasks. Here we always set "simple" priority by not setting
+	 * MMC_DATA_PRIO.
+	 */
 
 	/*
 	 * The block layer doesn't support all sector count
@@ -1638,8 +1647,10 @@ static void mmc_blk_data_prep(struct mmc_queue *mq, struct mmc_queue_req *mqrq,
 						brq->data.blocks);
 	}
 
-	if (do_rel_wr)
+	if (do_rel_wr) {
 		mmc_apply_rel_rw(brq, card, req);
+		brq->data.flags |= MMC_DATA_REL_WR;
+	}
 
 	/*
 	 * Data tag is used only during writing meta data to speed
@@ -1651,6 +1662,9 @@ static void mmc_blk_data_prep(struct mmc_queue *mq, struct mmc_queue_req *mqrq,
 		      ((brq->data.blocks * brq->data.blksz) >=
 		       card->ext_csd.data_tag_unit_size);
 
+	if (do_data_tag)
+		brq->data.flags |= MMC_DATA_DAT_TAG;
+
 	mmc_set_data_timeout(&brq->data, card);
 
 	brq->data.sg = mqrq->sg;