[PATCH v7 13/14] scsi: ufs: commit descriptors before setting the doorbell

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From	Yaniv Gardi <ygardi@codeaurora.org>
Newsgroups	linux.kernel
Subject	[PATCH v7 13/14] scsi: ufs: commit descriptors before setting the doorbell
Date	Mon, 01 Feb 2016 14:10:01 +0100
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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.

Reviewed-by: Dolev Raviv <draviv@codeaurora.org>
Signed-off-by: Gilad Broner <gbroner@codeaurora.org>
Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>
Signed-off-by: Yaniv Gardi <ygardi@codeaurora.org>

---
 drivers/scsi/ufs/ufshcd.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 1893a14..2fc678d 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -1625,6 +1625,8 @@ static int ufshcd_exec_dev_cmd(struct ufs_hba *hba,
 
 	hba->dev_cmd.complete = &wait;
 
+	/* Make sure descriptors are ready before ringing the doorbell */
+	wmb();
 	spin_lock_irqsave(hba->host->host_lock, flags);
 	ufshcd_send_command(hba, tag);
 	spin_unlock_irqrestore(hba->host->host_lock, flags);
-- 
1.8.5.2

-- 
QUALCOMM ISRAEL, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation

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[PATCH v7 13/14] scsi: ufs: commit descriptors before setting the doorbell Yaniv Gardi <ygardi@codeaurora.org> - 2016-02-01 14:10 +0100

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