[PATCH v1 1/2] scsi: ufs: Abort tasks before clear them from doorbell

[Can Guo <cang@codeaurora.org>]

To recovery non-fatal errors, no full reset is required, err_handler only
clears those pending TRs/TMRs so that scsi layer can re-issue them. In
current err_handler, TRs are directly cleared from UFS host's doorbell but
not aborted from device side. However, according to the UFSHCI JEDEC spec,
the host software shall use UTP Transfer Request List CLear Register to
clear a task from UFS host's doorbell only when a UTP Transfer Request is
expected to not be completed, e.g. when the host software receives a
“FUNCTION COMPLETE” Task Management response which means a Transfer Request
was aborted. To follow the UFSHCI JEDEC spec, in err_handler, aborts one TR
before clearing it from doorbell.

Signed-off-by: Can Guo <cang@codeaurora.org>
---
 drivers/scsi/ufs/ufshcd.c | 143 ++++++++++++++++++++++++++--------------------
 1 file changed, 81 insertions(+), 62 deletions(-)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index b8441ad..000895f 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -235,6 +235,7 @@ static int ufshcd_setup_hba_vreg(struct ufs_hba *hba, bool on);
 static int ufshcd_setup_vreg(struct ufs_hba *hba, bool on);
 static inline int ufshcd_config_vreg_hpm(struct ufs_hba *hba,
 					 struct ufs_vreg *vreg);
+static int ufshcd_try_to_abort_task(struct ufs_hba *hba, int tag);
 static int ufshcd_wb_buf_flush_enable(struct ufs_hba *hba);
 static int ufshcd_wb_buf_flush_disable(struct ufs_hba *hba);
 static int ufshcd_wb_ctrl(struct ufs_hba *hba, bool enable);
@@ -5657,8 +5658,8 @@ static void ufshcd_err_handler(struct work_struct *work)
 {
 	struct ufs_hba *hba;
 	unsigned long flags;
-	u32 err_xfer = 0;
-	u32 err_tm = 0;
+	bool err_xfer = false;
+	bool err_tm = false;
 	int err = 0;
 	int tag;
 	bool needs_reset = false;
@@ -5734,7 +5735,7 @@ static void ufshcd_err_handler(struct work_struct *work)
 	spin_unlock_irqrestore(hba->host->host_lock, flags);
 	/* Clear pending transfer requests */
 	for_each_set_bit(tag, &hba->outstanding_reqs, hba->nutrs) {
-		if (ufshcd_clear_cmd(hba, tag)) {
+		if (ufshcd_try_to_abort_task(hba, tag)) {
 			err_xfer = true;
 			goto lock_skip_pending_xfer_clear;
 		}
@@ -6486,7 +6487,7 @@ static void ufshcd_set_req_abort_skip(struct ufs_hba *hba, unsigned long bitmap)
 }
 
 /**
- * ufshcd_abort - abort a specific command
+ * ufshcd_try_to_abort_task - abort a specific task
  * @cmd: SCSI command pointer
  *
  * Abort the pending command in device by sending UFS_ABORT_TASK task management
@@ -6495,6 +6496,80 @@ static void ufshcd_set_req_abort_skip(struct ufs_hba *hba, unsigned long bitmap)
  * issued. To avoid that, first issue UFS_QUERY_TASK to check if the command is
  * really issued and then try to abort it.
  *
+ * Returns zero on success, non-zero on failure
+ */
+static int ufshcd_try_to_abort_task(struct ufs_hba *hba, int tag)
+{
+	struct ufshcd_lrb *lrbp = &hba->lrb[tag];
+	int err = 0;
+	int poll_cnt;
+	u8 resp = 0xF;
+	u32 reg;
+
+	for (poll_cnt = 100; poll_cnt; poll_cnt--) {
+		err = ufshcd_issue_tm_cmd(hba, lrbp->lun, lrbp->task_tag,
+				UFS_QUERY_TASK, &resp);
+		if (!err && resp == UPIU_TASK_MANAGEMENT_FUNC_SUCCEEDED) {
+			/* cmd pending in the device */
+			dev_err(hba->dev, "%s: cmd pending in the device. tag = %d\n",
+				__func__, tag);
+			break;
+		} else if (!err && resp == UPIU_TASK_MANAGEMENT_FUNC_COMPL) {
+			/*
+			 * cmd not pending in the device, check if it is
+			 * in transition.
+			 */
+			dev_err(hba->dev, "%s: cmd at tag %d not pending in the device.\n",
+				__func__, tag);
+			reg = ufshcd_readl(hba, REG_UTP_TRANSFER_REQ_DOOR_BELL);
+			if (reg & (1 << tag)) {
+				/* sleep for max. 200us to stabilize */
+				usleep_range(100, 200);
+				continue;
+			}
+			/* command completed already */
+			dev_err(hba->dev, "%s: cmd at tag %d successfully cleared from DB.\n",
+				__func__, tag);
+			goto out;
+		} else {
+			dev_err(hba->dev,
+				"%s: no response from device. tag = %d, err %d\n",
+				__func__, tag, err);
+			if (!err)
+				err = resp; /* service response error */
+			goto out;
+		}
+	}
+
+	if (!poll_cnt) {
+		err = -EBUSY;
+		goto out;
+	}
+
+	err = ufshcd_issue_tm_cmd(hba, lrbp->lun, lrbp->task_tag,
+			UFS_ABORT_TASK, &resp);
+	if (err || resp != UPIU_TASK_MANAGEMENT_FUNC_COMPL) {
+		if (!err) {
+			err = resp; /* service response error */
+			dev_err(hba->dev, "%s: issued. tag = %d, err %d\n",
+				__func__, tag, err);
+		}
+		goto out;
+	}
+
+	err = ufshcd_clear_cmd(hba, tag);
+	if (err)
+		dev_err(hba->dev, "%s: Failed clearing cmd at tag %d, err %d\n",
+			__func__, tag, err);
+
+out:
+	return err;
+}
+
+/**
+ * ufshcd_abort - scsi host template eh_abort_handler callback
+ * @cmd: SCSI command pointer
+ *
  * Returns SUCCESS/FAILED
  */
 static int ufshcd_abort(struct scsi_cmnd *cmd)
@@ -6504,8 +6579,6 @@ static int ufshcd_abort(struct scsi_cmnd *cmd)
 	unsigned long flags;
 	unsigned int tag;
 	int err = 0;
-	int poll_cnt;
-	u8 resp = 0xF;
 	struct ufshcd_lrb *lrbp;
 	u32 reg;
 
@@ -6574,63 +6647,9 @@ static int ufshcd_abort(struct scsi_cmnd *cmd)
 		goto out;
 	}
 
-	for (poll_cnt = 100; poll_cnt; poll_cnt--) {
-		err = ufshcd_issue_tm_cmd(hba, lrbp->lun, lrbp->task_tag,
-				UFS_QUERY_TASK, &resp);
-		if (!err && resp == UPIU_TASK_MANAGEMENT_FUNC_SUCCEEDED) {
-			/* cmd pending in the device */
-			dev_err(hba->dev, "%s: cmd pending in the device. tag = %d\n",
-				__func__, tag);
-			break;
-		} else if (!err && resp == UPIU_TASK_MANAGEMENT_FUNC_COMPL) {
-			/*
-			 * cmd not pending in the device, check if it is
-			 * in transition.
-			 */
-			dev_err(hba->dev, "%s: cmd at tag %d not pending in the device.\n",
-				__func__, tag);
-			reg = ufshcd_readl(hba, REG_UTP_TRANSFER_REQ_DOOR_BELL);
-			if (reg & (1 << tag)) {
-				/* sleep for max. 200us to stabilize */
-				usleep_range(100, 200);
-				continue;
-			}
-			/* command completed already */
-			dev_err(hba->dev, "%s: cmd at tag %d successfully cleared from DB.\n",
-				__func__, tag);
-			goto out;
-		} else {
-			dev_err(hba->dev,
-				"%s: no response from device. tag = %d, err %d\n",
-				__func__, tag, err);
-			if (!err)
-				err = resp; /* service response error */
-			goto out;
-		}
-	}
-
-	if (!poll_cnt) {
-		err = -EBUSY;
-		goto out;
-	}
-
-	err = ufshcd_issue_tm_cmd(hba, lrbp->lun, lrbp->task_tag,
-			UFS_ABORT_TASK, &resp);
-	if (err || resp != UPIU_TASK_MANAGEMENT_FUNC_COMPL) {
-		if (!err) {
-			err = resp; /* service response error */
-			dev_err(hba->dev, "%s: issued. tag = %d, err %d\n",
-				__func__, tag, err);
-		}
-		goto out;
-	}
-
-	err = ufshcd_clear_cmd(hba, tag);
-	if (err) {
-		dev_err(hba->dev, "%s: Failed clearing cmd at tag %d, err %d\n",
-			__func__, tag, err);
+	err = ufshcd_try_to_abort_task(hba, tag);
+	if (err)
 		goto out;
-	}
 
 	spin_lock_irqsave(host->host_lock, flags);
 	__ufshcd_transfer_req_compl(hba, (1UL << tag));
-- 
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