From ad1a1b9cd67a4b5bee8a62454336d94f9e816c1f Mon Sep 17 00:00:00 2001 From: Gilad Broner Date: Mon, 17 Oct 2016 17:09:36 -0700 Subject: [PATCH] scsi: ufs: commit descriptors before setting the doorbell Add a write memory barrier to make sure descriptors prepared are actually written to memory before ringing the doorbell. We have also added the write memory barrier after ringing the doorbell register so that controller sees the new request immediately. Signed-off-by: Gilad Broner Signed-off-by: Subhash Jadavani Signed-off-by: Martin K. Petersen --- drivers/scsi/ufs/ufshcd.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c index d46709ed0555..2fbbe62f3696 100644 --- a/drivers/scsi/ufs/ufshcd.c +++ b/drivers/scsi/ufs/ufshcd.c @@ -878,6 +878,8 @@ void ufshcd_send_command(struct ufs_hba *hba, unsigned int task_tag) ufshcd_clk_scaling_start_busy(hba); __set_bit(task_tag, &hba->outstanding_reqs); ufshcd_writel(hba, 1 << task_tag, REG_UTP_TRANSFER_REQ_DOOR_BELL); + /* Make sure that doorbell is committed immediately */ + wmb(); } /** @@ -1475,6 +1477,8 @@ static int ufshcd_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *cmd) clear_bit_unlock(tag, &hba->lrb_in_use); goto out; } + /* Make sure descriptors are ready before ringing the doorbell */ + wmb(); /* issue command to the controller */ spin_lock_irqsave(hba->host->host_lock, flags); @@ -1585,6 +1589,8 @@ static int ufshcd_wait_for_dev_cmd(struct ufs_hba *hba, time_left = wait_for_completion_timeout(hba->dev_cmd.complete, msecs_to_jiffies(max_timeout)); + /* Make sure descriptors are ready before ringing the doorbell */ + wmb(); spin_lock_irqsave(hba->host->host_lock, flags); hba->dev_cmd.complete = NULL; if (likely(time_left)) { @@ -4322,6 +4328,8 @@ static int ufshcd_issue_tm_cmd(struct ufs_hba *hba, int lun_id, int task_id, wmb(); ufshcd_writel(hba, 1 << free_slot, REG_UTP_TASK_REQ_DOOR_BELL); + /* Make sure that doorbell is committed immediately */ + wmb(); spin_unlock_irqrestore(host->host_lock, flags);