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[PATCH v4 14/15] scsi: ufs: commit descriptors before setting the doorbell

From Yaniv Gardi <ygardi@codeaurora.org>
Newsgroups linux.kernel
Subject [PATCH v4 14/15] scsi: ufs: commit descriptors before setting the doorbell
Date 2015-10-25 16:00 +0100
Message-ID <qnuW8-4fF-91@gated-at.bofh.it> (permalink)
References <qnuW5-4fF-3@gated-at.bofh.it>
Organization linux.* mail to news gateway

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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.

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 14bebc5..c87bd4b 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -1628,6 +1628,8 @@ 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

-- 
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Thread

[PATCH v4 00/15] Big fixes, retries, handle a race condition Yaniv Gardi <ygardi@codeaurora.org> - 2015-10-25 16:00 +0100
  [PATCH v4 08/15] scsi: ufs: add retries to dme_peer get and set attribute Yaniv Gardi <ygardi@codeaurora.org> - 2015-10-25 16:00 +0100
  [PATCH v4 04/15] scsi: ufs: clear outstanding_request bit in case query timeout Yaniv Gardi <ygardi@codeaurora.org> - 2015-10-25 16:00 +0100
  [PATCH v4 13/15] scsi: ufs: add missing memory barriers Yaniv Gardi <ygardi@codeaurora.org> - 2015-10-25 16:00 +0100
  [PATCH v4 15/15] scsi: ufs: add wrapper for retrying sending query attribute Yaniv Gardi <ygardi@codeaurora.org> - 2015-10-25 16:00 +0100
  [PATCH v4 06/15] scsi: ufs: avoid exception event handler racing with PM callbacks Yaniv Gardi <ygardi@codeaurora.org> - 2015-10-25 16:00 +0100
  [PATCH v4 10/15] scsi: ufs: fix error recovery after the hibern8 exit failure Yaniv Gardi <ygardi@codeaurora.org> - 2015-10-25 16:00 +0100
  [PATCH v4 03/15] scsi: ufs: verify command tag validity Yaniv Gardi <ygardi@codeaurora.org> - 2015-10-25 16:00 +0100
  [PATCH v4 09/15] scsi: ufs: add retries for hibern8 enter Yaniv Gardi <ygardi@codeaurora.org> - 2015-10-25 16:00 +0100
  [PATCH v4 14/15] scsi: ufs: commit descriptors before setting the doorbell Yaniv Gardi <ygardi@codeaurora.org> - 2015-10-25 16:00 +0100
  [PATCH v4 05/15] scsi: ufs: increase fDeviceInit query response timeout Yaniv Gardi <ygardi@codeaurora.org> - 2015-10-25 16:00 +0100
  [PATCH v4 02/15] scsi: ufs: clear fields UTRD, UPIU req and rsp before new transfers Yaniv Gardi <ygardi@codeaurora.org> - 2015-10-25 16:00 +0100
  [PATCH v4 01/15] scsi: ufs: clear UTRD, UPIU req and rsp before new transfers Yaniv Gardi <ygardi@codeaurora.org> - 2015-10-25 16:10 +0100
  [PATCH v4 07/15] scsi: ufs: set REQUEST_SENSE command size to 18 bytes Yaniv Gardi <ygardi@codeaurora.org> - 2015-10-25 16:10 +0100

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