scsi: ufs: core: mcq: Find hardware queue to queue request

Add support to find the hardware queue on which the request would be
queued.  Since the very first queue is to serve device commands, an offset
of 1 is added to the index of the hardware 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>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/ufs/core/ufs-mcq.c

@@ -92,6 +92,25 @@ void ufshcd_mcq_config_mac(struct ufs_hba *hba, u32 max_active_cmds)
 	ufshcd_writel(hba, val, REG_UFS_MCQ_CFG);
 }
 
+/**
+ * ufshcd_mcq_req_to_hwq - find the hardware queue on which the
+ * request would be issued.
+ * @hba - per adapter instance
+ * @req - pointer to the request to be issued
+ *
+ * Returns the hardware queue instance on which the request would
+ * be queued.
+ */
+struct ufs_hw_queue *ufshcd_mcq_req_to_hwq(struct ufs_hba *hba,
+					 struct request *req)
+{
+	u32 utag = blk_mq_unique_tag(req);
+	u32 hwq = blk_mq_unique_tag_to_hwq(utag);
+
+	/* uhq[0] is used to serve device commands */
+	return &hba->uhq[hwq + UFSHCD_MCQ_IO_QUEUE_OFFSET];
+}
+
 /**
  * ufshcd_mcq_decide_queue_depth - decide the queue depth
  * @hba - per adapter instance

drivers/ufs/core/ufshcd-priv.h

@@ -67,7 +67,10 @@ int ufshcd_mcq_memory_alloc(struct ufs_hba *hba);
 void ufshcd_mcq_make_queues_operational(struct ufs_hba *hba);
 void ufshcd_mcq_config_mac(struct ufs_hba *hba, u32 max_active_cmds);
 void ufshcd_mcq_select_mcq_mode(struct ufs_hba *hba);
+struct ufs_hw_queue *ufshcd_mcq_req_to_hwq(struct ufs_hba *hba,
+					   struct request *req);
 
+#define UFSHCD_MCQ_IO_QUEUE_OFFSET	1
 #define SD_ASCII_STD true
 #define SD_RAW false
 int ufshcd_read_string_desc(struct ufs_hba *hba, u8 desc_index,

drivers/ufs/core/ufshcd.c

@@ -2935,6 +2935,9 @@ static int ufshcd_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *cmd)
 		goto out;
 	}
 
+	if (is_mcq_enabled(hba))
+		hwq = ufshcd_mcq_req_to_hwq(hba, scsi_cmd_to_rq(cmd));
+
 	ufshcd_send_command(hba, tag, hwq);
 
 out: