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[PATCH v3 09/15] scsi: ufs: add retries for hibern8 enter

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If hibern8 enter command fails then UFS link state may be unknown which
may result into timeout of all the commands issued after failure.

This change does 2 things (for pre-defined number of retry counts) after
hibern8 enter failure:
1. Recovers the UFS link to active state
2. If link is recovered to active state, tries to put the UFS link in
   hibern8 enter again until retry count expires.

Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>
Signed-off-by: Yaniv Gardi <ygardi@codeaurora.org>

---
 drivers/scsi/ufs/ufshcd.c | 26 ++++++++++++++++++++++++--
 1 file changed, 24 insertions(+), 2 deletions(-)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 8d5bdf0..5800b08 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -75,6 +75,9 @@
 /* maximum number of link-startup retries */
 #define DME_LINKSTARTUP_RETRIES 3
 
+/* Maximum retries for Hibern8 enter */
+#define UIC_HIBERN8_ENTER_RETRIES 3
+
 /* maximum number of reset retries before giving up */
 #define MAX_HOST_RESET_RETRIES 5
 
@@ -2389,13 +2392,32 @@ out:
 	return ret;
 }
 
-static int ufshcd_uic_hibern8_enter(struct ufs_hba *hba)
+static int __ufshcd_uic_hibern8_enter(struct ufs_hba *hba)
 {
+	int ret;
 	struct uic_command uic_cmd = {0};
 
 	uic_cmd.command = UIC_CMD_DME_HIBER_ENTER;
+	ret = ufshcd_uic_pwr_ctrl(hba, &uic_cmd);
+
+	if (ret)
+		dev_err(hba->dev, "%s: hibern8 enter failed. ret = %d",
+			__func__, ret);
+
+	return ret;
+}
+
+static int ufshcd_uic_hibern8_enter(struct ufs_hba *hba)
+{
+	int ret = 0, retries;
 
-	return ufshcd_uic_pwr_ctrl(hba, &uic_cmd);
+	for (retries = UIC_HIBERN8_ENTER_RETRIES; retries > 0; retries--) {
+		ret = __ufshcd_uic_hibern8_enter(hba);
+		if (!ret || ret == -ENOLINK)
+			goto out;
+	}
+out:
+	return ret;
 }
 
 static int ufshcd_uic_hibern8_exit(struct ufs_hba *hba)
-- 
1.8.5.2

-- 
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[PATCH v3 00/15] Big fixes, retries, handle a race condition Yaniv Gardi <ygardi@codeaurora.org> - 2015-09-02 12:20 +0200
  [PATCH v3 10/15] scsi: ufs: fix error recovery after the hibern8 exit failure Yaniv Gardi <ygardi@codeaurora.org> - 2015-09-02 12:20 +0200
  [PATCH v3 02/15] scsi: ufs: clear fields UTRD, UPIU req and rsp before new transfers Yaniv Gardi <ygardi@codeaurora.org> - 2015-09-02 12:20 +0200
  [PATCH v3 01/15] scsi: ufs: clear UTRD, UPIU req and rsp before new transfers Yaniv Gardi <ygardi@codeaurora.org> - 2015-09-02 12:20 +0200
  [PATCH v3 08/15] scsi: ufs: add retries to dme_peer get and set attribute Yaniv Gardi <ygardi@codeaurora.org> - 2015-09-02 12:20 +0200
  [PATCH v3 04/15] scsi: ufs: clear outstanding_request bit in case query timeout Yaniv Gardi <ygardi@codeaurora.org> - 2015-09-02 12:20 +0200
  [PATCH v3 12/15] scsi: ufs: reduce the interrupts for power mode change requests Yaniv Gardi <ygardi@codeaurora.org> - 2015-09-02 12:20 +0200
  [PATCH v3 07/15] scsi: ufs: set REQUEST_SENSE command size to 18 bytes Yaniv Gardi <ygardi@codeaurora.org> - 2015-09-02 12:20 +0200
  [PATCH v3 09/15] scsi: ufs: add retries for hibern8 enter Yaniv Gardi <ygardi@codeaurora.org> - 2015-09-02 12:20 +0200

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