scsi: ufs: core: mcq: Add completion support in poll

Complete CQE requests in poll. Assumption is that several poll completion
may happen in different CPUs for the same completion queue. Hence a spin
lock protection is added.

Co-developed-by: Can Guo <[email protected]>
Signed-off-by: Can Guo <[email protected]>
Signed-off-by: Asutosh Das <[email protected]>
Reviewed-by: Bart Van Assche <[email protected]>
Reviewed-by: Manivannan Sadhasivam <[email protected]>
Reviewed-by: Stanley Chu <[email protected]>
Signed-off-by: Martin K. Petersen <[email protected]>

Author: Asutosh Das

drivers/ufs/core/ufs-mcq.c

@@ -294,6 +294,18 @@ unsigned long ufshcd_mcq_poll_cqe_nolock(struct ufs_hba *hba,
 	return completed_reqs;
 }
 
+unsigned long ufshcd_mcq_poll_cqe_lock(struct ufs_hba *hba,
+				       struct ufs_hw_queue *hwq)
+{
+	unsigned long completed_reqs;
+
+	spin_lock(&hwq->cq_lock);
+	completed_reqs = ufshcd_mcq_poll_cqe_nolock(hba, hwq);
+	spin_unlock(&hwq->cq_lock);
+
+	return completed_reqs;
+}
+
 void ufshcd_mcq_make_queues_operational(struct ufs_hba *hba)
 {
 	struct ufs_hw_queue *hwq;
@@ -390,6 +402,7 @@ int ufshcd_mcq_init(struct ufs_hba *hba)
 		hwq = &hba->uhq[i];
 		hwq->max_entries = hba->nutrs;
 		spin_lock_init(&hwq->sq_lock);
+		spin_lock_init(&hwq->cq_lock);
 	}
 
 	/* The very first HW queue serves device commands */

drivers/ufs/core/ufshcd-priv.h

@@ -75,6 +75,8 @@ unsigned long ufshcd_mcq_poll_cqe_nolock(struct ufs_hba *hba,
 					 struct ufs_hw_queue *hwq);
 struct ufs_hw_queue *ufshcd_mcq_req_to_hwq(struct ufs_hba *hba,
 					   struct request *req);
+unsigned long ufshcd_mcq_poll_cqe_lock(struct ufs_hba *hba,
+				       struct ufs_hw_queue *hwq);
 
 #define UFSHCD_MCQ_IO_QUEUE_OFFSET	1
 #define SD_ASCII_STD true

drivers/ufs/core/ufshcd.c

@@ -5461,6 +5461,13 @@ static int ufshcd_poll(struct Scsi_Host *shost, unsigned int queue_num)
 	struct ufs_hba *hba = shost_priv(shost);
 	unsigned long completed_reqs, flags;
 	u32 tr_doorbell;
+	struct ufs_hw_queue *hwq;
+
+	if (is_mcq_enabled(hba)) {
+		hwq = &hba->uhq[queue_num + UFSHCD_MCQ_IO_QUEUE_OFFSET];
+
+		return ufshcd_mcq_poll_cqe_lock(hba, hwq);
+	}
 
 	spin_lock_irqsave(&hba->outstanding_lock, flags);
 	tr_doorbell = ufshcd_readl(hba, REG_UTP_TRANSFER_REQ_DOOR_BELL);

include/ufs/ufshcd.h

@@ -1086,6 +1086,7 @@ struct ufs_hba {
  * @sq_lock: serialize submission queue access
  * @cq_tail_slot: current slot to which CQ tail pointer is pointing
  * @cq_head_slot: current slot to which CQ head pointer is pointing
+ * @cq_lock: Synchronize between multiple polling instances
  */
 struct ufs_hw_queue {
 	void __iomem *mcq_sq_head;
@@ -1103,6 +1104,7 @@ struct ufs_hw_queue {
 	spinlock_t sq_lock;
 	u32 cq_tail_slot;
 	u32 cq_head_slot;
+	spinlock_t cq_lock;
 };
 
 static inline bool is_mcq_enabled(struct ufs_hba *hba)