From: Sujit Reddy Thumma <sthumma@xxxxxxxxxxxxxx>
In some cases, due to hardware timing issues the Uni-Pro link-startup
might fail. The UFS HCI recovery procedure contradicts the Uni-Pro
sequence. The UFS HCI specifies to resend DME_LINKSTARTUP command
after IS.ULLS (link-lost interrupt) is received. The Uni-Pro specifies
that if link-startup fails the link is in "down" state. The link-lost is
indicated to the DME user only when the link is up. Hence, the UFS HCI
recovery procedure of waiting for IS.ULLS and retrying link-startup may
not work properly.
In order to resolve the ambiguity, reset the host controller to make
sure the link is in down state and retry the link-startup.
Signed-off-by: Sujit Reddy Thumma <sthumma@xxxxxxxxxxxxxx>
Signed-off-by: Dolev Raviv <draviv@xxxxxxxxxxxxxx>
---
drivers/scsi/ufs/ufshcd.c | 25 ++++++++++++++++++++++++-
1 file changed, 24 insertions(+), 1 deletion(-)
diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index f189e8a..3776f5d 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -58,6 +58,9 @@
/* Task management command timeout */
#define TM_CMD_TIMEOUT 100 /* msecs */
+/* maximum number of link-startup retries */
+#define DME_LINKSTARTUP_RETRIES 3
+
/* Expose the flag value from utp_upiu_query.value */
#define MASK_QUERY_UPIU_FLAG_LOC 0xFF
@@ -1923,12 +1926,32 @@ static int ufshcd_hba_enable(struct ufs_hba *hba)
static int ufshcd_link_startup(struct ufs_hba *hba)
{
int ret;
+ int retries = DME_LINKSTARTUP_RETRIES;
/* enable UIC related interrupts */
ufshcd_enable_intr(hba, UIC_COMMAND_COMPL);
- ret = ufshcd_dme_link_startup(hba);
+ do {
+ ret = ufshcd_dme_link_startup(hba);
+
+ /* check if device is detected by inter-connect layer */
+ if (!ret && !ufshcd_is_device_present(hba)) {
+ dev_err(hba->dev, "%s: Device not present\n", __func__);
+ ret = -ENXIO;
+ goto out;
+ }
+
+ /*
+ * DME link lost indication is only received when link is up,
+ * but we can't be sure if the link is up until link startup
+ * succeeds. So reset the local Uni-Pro and try again.
+ */
+ if (ret && ufshcd_hba_enable(hba))
+ goto out;
+ } while (ret && retries--);
+
if (ret)
+ /* failed to get the link up... retire */
goto out;
ret = ufshcd_make_hba_operational(hba);
--
1.8.5.2
--
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