scsi: ufs: core: mcq: Use shared tags for MCQ mode

Enable shared tags for MCQ. For UFS, this should not have a huge
performance impact. It however simplifies the MCQ implementation and reuses
most of the existing code in the issue and completion path.  Also add
multiple queue mapping to map_queue().
Co-developed-by: Can Guo <quic_cang@quicinc.com>
Signed-off-by: Can Guo <quic_cang@quicinc.com>
Signed-off-by: Asutosh Das <quic_asutoshd@quicinc.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Manivannan Sadhasivam <mani@kernel.org>
Reviewed-by: Stanley Chu <stanley.chu@mediatek.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/ufs/core/ufs-mcq.c

@@ -280,6 +280,7 @@ void ufshcd_mcq_make_queues_operational(struct ufs_hba *hba)
 
 int ufshcd_mcq_init(struct ufs_hba *hba)
 {
+	struct Scsi_Host *host = hba->host;
 	struct ufs_hw_queue *hwq;
 	int ret, i;
 
@@ -315,5 +316,6 @@ int ufshcd_mcq_init(struct ufs_hba *hba)
 	/* Give dev_cmd_queue the minimal number of entries */
 	hba->dev_cmd_queue->max_entries = MAX_DEV_CMD_ENTRIES;
 
+	host->host_tagset = 1;
 	return 0;
 }

drivers/ufs/core/ufshcd.c

@@ -2776,24 +2776,28 @@ static inline bool is_device_wlun(struct scsi_device *sdev)
  */
 static void ufshcd_map_queues(struct Scsi_Host *shost)
 {
-	int i;
+	struct ufs_hba *hba = shost_priv(shost);
+	int i, queue_offset = 0;
+
+	if (!is_mcq_supported(hba)) {
+		hba->nr_queues[HCTX_TYPE_DEFAULT] = 1;
+		hba->nr_queues[HCTX_TYPE_READ] = 0;
+		hba->nr_queues[HCTX_TYPE_POLL] = 1;
+		hba->nr_hw_queues = 1;
+	}
 
 	for (i = 0; i < shost->nr_maps; i++) {
 		struct blk_mq_queue_map *map = &shost->tag_set.map[i];
 
-		switch (i) {
-		case HCTX_TYPE_DEFAULT:
-		case HCTX_TYPE_POLL:
-			map->nr_queues = 1;
-			break;
-		case HCTX_TYPE_READ:
-			map->nr_queues = 0;
+		map->nr_queues = hba->nr_queues[i];
+		if (!map->nr_queues)
 			continue;
-		default:
-			WARN_ON_ONCE(true);
-		}
-		map->queue_offset = 0;
+		map->queue_offset = queue_offset;
+		if (i == HCTX_TYPE_POLL && !is_mcq_supported(hba))
+			map->queue_offset = 0;
+
 		blk_mq_map_queues(map);
+		queue_offset += map->nr_queues;
 	}
 }