mmc: card: add read/write support in command queue mode

Command queueing is defined in eMMC-5.1. It is designed for
higher performance by ensuring upto 32 requests to be serviced
at a time.

Adds read/write support for CMDQ enabled devices.

Change-Id: I136ddea8e5ca57eb4f85ca6e72c60001a7e24f78
Signed-off-by: Sujit Reddy Thumma <sthumma@codeaurora.org>
Signed-off-by: Asutosh Das <asutoshd@codeaurora.org>
Signed-off-by: Konstantin Dorfman <kdorfman@codeaurora.org>
Signed-off-by: Venkat Gopalakrishnan <venkatg@codeaurora.org>
[subhashj@codeaurora.org: fixed trivial merge conflicts]
Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>
[xiaonian@codeaurora.org: fixed trivial merge conflicts]
Signed-off-by: Xiaonian Wang <xiaonian@codeaurora.org>
diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
index de841f0..a78622d 100644
--- a/drivers/mmc/card/block.c
+++ b/drivers/mmc/card/block.c
@@ -36,6 +36,7 @@
 #include <linux/capability.h>
 #include <linux/compat.h>
 #include <linux/pm_runtime.h>
+#include <linux/ioprio.h>
 #include <linux/idr.h>
 
 #include <linux/mmc/ioctl.h>
@@ -118,6 +119,7 @@
 #define MMC_BLK_CMD23	(1 << 0)	/* Can do SET_BLOCK_COUNT for multiblock */
 #define MMC_BLK_REL_WR	(1 << 1)	/* MMC Reliable write support */
 #define MMC_BLK_PACKED_CMD	(1 << 2)	/* MMC packed command support */
+#define MMC_BLK_CMD_QUEUE	(1 << 3) /* MMC command queue support */
 
 	unsigned int	usage;
 	unsigned int	read_only;
@@ -156,6 +158,8 @@
 static inline int mmc_blk_part_switch(struct mmc_card *card,
 				      struct mmc_blk_data *md);
 static int get_card_status(struct mmc_card *card, u32 *status, int retries);
+static int mmc_blk_cmdq_switch(struct mmc_card *card,
+			       struct mmc_blk_data *md, bool enable);
 
 static inline void mmc_blk_clear_packed(struct mmc_queue_req *mqrq)
 {
@@ -1294,6 +1298,44 @@
 #endif
 };
 
+static int mmc_blk_cmdq_switch(struct mmc_card *card,
+			       struct mmc_blk_data *md, bool enable)
+{
+	int ret = 0;
+	bool cmdq_mode = !!mmc_card_cmdq(card);
+
+	if (!(card->host->caps2 & MMC_CAP2_CMD_QUEUE) ||
+	    !card->ext_csd.cmdq_support ||
+	    (enable && !(md->flags & MMC_BLK_CMD_QUEUE)) ||
+	    (cmdq_mode == enable))
+		return 0;
+
+	if (enable) {
+		ret = mmc_set_blocklen(card, MMC_CARD_CMDQ_BLK_SIZE);
+		if (ret) {
+			pr_err("%s: failed (%d) to set block-size to %d\n",
+			       __func__, ret, MMC_CARD_CMDQ_BLK_SIZE);
+			goto out;
+		}
+	}
+
+	ret = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
+			 EXT_CSD_CMDQ, enable,
+			 card->ext_csd.generic_cmd6_time);
+	if (ret) {
+		pr_err("%s: cmdq mode %sable failed %d\n",
+		       md->disk->disk_name, enable ? "en" : "dis", ret);
+		goto out;
+	}
+
+	if (enable)
+		mmc_card_set_cmdq(card);
+	else
+		mmc_card_clr_cmdq(card);
+out:
+	return ret;
+}
+
 static inline int mmc_blk_part_switch(struct mmc_card *card,
 				      struct mmc_blk_data *md)
 {
@@ -1307,6 +1349,13 @@
 	if (mmc_card_mmc(card)) {
 		u8 part_config = card->ext_csd.part_config;
 
+		if (md->part_type) {
+			/* disable CQ mode for non-user data partitions */
+			ret = mmc_blk_cmdq_switch(card, md, false);
+			if (ret)
+				return ret;
+		}
+
 		if (md->part_type == EXT_CSD_PART_CONFIG_ACC_RPMB)
 			mmc_retune_pause(card->host);
 
@@ -2782,6 +2831,166 @@
 	mmc_blk_clear_packed(mq_rq);
 }
 
+static int mmc_blk_cmdq_start_req(struct mmc_host *host,
+				  struct mmc_cmdq_req *cmdq_req)
+{
+	struct mmc_request *mrq = &cmdq_req->mrq;
+
+	mrq->done = mmc_blk_cmdq_req_done;
+	return mmc_cmdq_start_req(host, cmdq_req);
+}
+
+#define IS_RT_CLASS_REQ(x)     \
+	(IOPRIO_PRIO_CLASS(req_get_ioprio(x)) == IOPRIO_CLASS_RT)
+
+static struct mmc_cmdq_req *mmc_blk_cmdq_rw_prep(
+		struct mmc_queue_req *mqrq, struct mmc_queue *mq)
+{
+	struct mmc_card *card = mq->card;
+	struct request *req = mqrq->req;
+	struct mmc_blk_data *md = mq->data;
+	bool do_rel_wr = mmc_req_rel_wr(req) && (md->flags & MMC_BLK_REL_WR);
+	bool do_data_tag;
+	bool read_dir = (rq_data_dir(req) == READ);
+	bool prio = IS_RT_CLASS_REQ(req);
+	struct mmc_cmdq_req *cmdq_rq = &mqrq->cmdq_req;
+
+	memset(&mqrq->cmdq_req, 0, sizeof(struct mmc_cmdq_req));
+
+	cmdq_rq->tag = req->tag;
+	if (read_dir) {
+		cmdq_rq->cmdq_req_flags |= DIR;
+		cmdq_rq->data.flags = MMC_DATA_READ;
+	} else {
+		cmdq_rq->data.flags = MMC_DATA_WRITE;
+	}
+	if (prio)
+		cmdq_rq->cmdq_req_flags |= PRIO;
+
+	if (do_rel_wr)
+		cmdq_rq->cmdq_req_flags |= REL_WR;
+
+	cmdq_rq->data.blocks = blk_rq_sectors(req);
+	cmdq_rq->blk_addr = blk_rq_pos(req);
+	cmdq_rq->data.blksz = MMC_CARD_CMDQ_BLK_SIZE;
+
+	mmc_set_data_timeout(&cmdq_rq->data, card);
+
+	do_data_tag = (card->ext_csd.data_tag_unit_size) &&
+		(req->cmd_flags & REQ_META) &&
+		(rq_data_dir(req) == WRITE) &&
+		((cmdq_rq->data.blocks * cmdq_rq->data.blksz) >=
+		 card->ext_csd.data_tag_unit_size);
+	if (do_data_tag)
+		cmdq_rq->cmdq_req_flags |= DAT_TAG;
+	cmdq_rq->data.sg = mqrq->sg;
+	cmdq_rq->data.sg_len = mmc_queue_map_sg(mq, mqrq);
+
+	/*
+	 * Adjust the sg list so it is the same size as the
+	 * request.
+	 */
+	if (cmdq_rq->data.blocks > card->host->max_blk_count)
+		cmdq_rq->data.blocks = card->host->max_blk_count;
+
+	if (cmdq_rq->data.blocks != blk_rq_sectors(req)) {
+		int i, data_size = cmdq_rq->data.blocks << 9;
+		struct scatterlist *sg;
+
+		for_each_sg(cmdq_rq->data.sg, sg, cmdq_rq->data.sg_len, i) {
+			data_size -= sg->length;
+			if (data_size <= 0) {
+				sg->length += data_size;
+				i++;
+				break;
+			}
+		}
+		cmdq_rq->data.sg_len = i;
+	}
+
+	mqrq->cmdq_req.cmd_flags = req->cmd_flags;
+	mqrq->cmdq_req.mrq.req = mqrq->req;
+	mqrq->cmdq_req.mrq.cmdq_req = &mqrq->cmdq_req;
+	mqrq->cmdq_req.mrq.data = &mqrq->cmdq_req.data;
+	mqrq->req->special = mqrq;
+
+	pr_debug("%s: %s: mrq: 0x%p req: 0x%p mqrq: 0x%p bytes to xf: %d mmc_cmdq_req: 0x%p card-addr: 0x%08x dir(r-1/w-0): %d\n",
+		 mmc_hostname(card->host), __func__, &mqrq->cmdq_req.mrq,
+		 mqrq->req, mqrq, (cmdq_rq->data.blocks * cmdq_rq->data.blksz),
+		 cmdq_rq, cmdq_rq->blk_addr,
+		 (cmdq_rq->cmdq_req_flags & DIR) ? 1 : 0);
+
+	return &mqrq->cmdq_req;
+}
+
+static int mmc_blk_cmdq_issue_rw_rq(struct mmc_queue *mq, struct request *req)
+{
+	struct mmc_queue_req *active_mqrq;
+	struct mmc_card *card = mq->card;
+	struct mmc_host *host = card->host;
+	struct mmc_cmdq_req *mc_rq;
+	int ret = 0;
+
+	BUG_ON((req->tag < 0) || (req->tag > card->ext_csd.cmdq_depth));
+	BUG_ON(test_and_set_bit(req->tag, &host->cmdq_ctx.active_reqs));
+
+	active_mqrq = &mq->mqrq_cmdq[req->tag];
+	active_mqrq->req = req;
+
+	mc_rq = mmc_blk_cmdq_rw_prep(active_mqrq, mq);
+
+	ret = mmc_blk_cmdq_start_req(card->host, mc_rq);
+	return ret;
+}
+
+/* invoked by block layer in softirq context */
+void mmc_blk_cmdq_complete_rq(struct request *rq)
+{
+	struct mmc_queue_req *mq_rq = rq->special;
+	struct mmc_request *mrq = &mq_rq->cmdq_req.mrq;
+	struct mmc_host *host = mrq->host;
+	struct mmc_cmdq_context_info *ctx_info = &host->cmdq_ctx;
+	struct mmc_cmdq_req *cmdq_req = &mq_rq->cmdq_req;
+	struct mmc_queue *mq = (struct mmc_queue *)rq->q->queuedata;
+	int err = 0;
+
+	if (mrq->cmd && mrq->cmd->error)
+		err = mrq->cmd->error;
+	else if (mrq->data && mrq->data->error)
+		err = mrq->data->error;
+
+	mmc_cmdq_post_req(host, mrq, err);
+	if (err) {
+		pr_err("%s: %s: txfr error: %d\n", mmc_hostname(mrq->host),
+		       __func__, err);
+		set_bit(CMDQ_STATE_ERR, &ctx_info->curr_state);
+		WARN_ON(1);
+	}
+
+	BUG_ON(!test_and_clear_bit(cmdq_req->tag,
+				   &ctx_info->active_reqs));
+
+	blk_end_request(rq, err, cmdq_req->data.bytes_xfered);
+
+	if (test_and_clear_bit(0, &ctx_info->req_starved))
+		blk_run_queue(mq->queue);
+
+	mmc_release_host(host);
+	return;
+}
+
+/*
+ * Complete reqs from block layer softirq context
+ * Invoked in irq context
+ */
+void mmc_blk_cmdq_req_done(struct mmc_request *mrq)
+{
+	struct request *req = mrq->req;
+
+	blk_complete_request(req);
+}
+EXPORT_SYMBOL(mmc_blk_cmdq_req_done);
+
 static int mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *rqc)
 {
 	struct mmc_blk_data *md = mq->data;
@@ -2977,6 +3186,28 @@
 	return 0;
 }
 
+static int mmc_blk_cmdq_issue_rq(struct mmc_queue *mq, struct request *req)
+{
+	int ret;
+	struct mmc_blk_data *md = mq->data;
+	struct mmc_card *card = md->queue.card;
+
+	mmc_claim_host(card->host);
+	ret = mmc_blk_part_switch(card, md);
+	if (ret) {
+		pr_err("%s: %s: partition switch failed %d\n",
+				md->disk->disk_name, __func__, ret);
+		blk_end_request_all(req, ret);
+		mmc_release_host(card->host);
+		goto switch_failure;
+	}
+
+	ret = mmc_blk_cmdq_issue_rw_rq(mq, req);
+
+switch_failure:
+	return ret;
+}
+
 int mmc_blk_issue_rq(struct mmc_queue *mq, struct request *req)
 {
 	int ret;
@@ -3151,12 +3382,18 @@
 	if (mmc_card_mmc(card) &&
 	    md->flags & MMC_BLK_CMD23 &&
 	    ((card->ext_csd.rel_param & EXT_CSD_WR_REL_PARAM_EN) ||
-	     card->ext_csd.rel_sectors)) {
+	     card->ext_csd.rel_sectors) && !card->cmdq_init) {
 		md->flags |= MMC_BLK_REL_WR;
 		blk_queue_write_cache(md->queue.queue, true, true);
 	}
 
-	if (mmc_card_mmc(card) &&
+	if (card->cmdq_init) {
+		md->flags |= MMC_BLK_CMD_QUEUE;
+		md->queue.cmdq_complete_fn = mmc_blk_cmdq_complete_rq;
+		md->queue.cmdq_issue_fn = mmc_blk_cmdq_issue_rq;
+	}
+
+	if (mmc_card_mmc(card) && !card->cmdq_init &&
 	    (area_type == MMC_BLK_DATA_AREA_MAIN) &&
 	    (md->flags & MMC_BLK_CMD23) &&
 	    card->ext_csd.packed_event_en) {
@@ -3269,6 +3506,8 @@
 		mmc_cleanup_queue(&md->queue);
 		if (md->flags & MMC_BLK_PACKED_CMD)
 			mmc_packed_clean(&md->queue);
+		if (md->flags & MMC_BLK_CMD_QUEUE)
+			mmc_cmdq_clean(&md->queue, card);
 		device_remove_file(disk_to_dev(md->disk),
 				   &md->num_wr_reqs_to_start_packing);
 		if (md->disk->flags & GENHD_FL_UP) {