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scsi: ufs: fix error handing during hibern8 enter

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During clock gating (ufshcd_gate_work()), we first put the link hibern8 by
calling ufshcd_uic_hibern8_enter() and if ufshcd_uic_hibern8_enter()
returns success (0) then we gate all the clocks.
Now let’s zoom in to what ufshcd_uic_hibern8_enter() does internally:
It calls __ufshcd_uic_hibern8_enter() which on detecting the LINERESET,
initiates the full recovery and puts the link back to highest HS gear and
returns success (0) to ufshcd_uic_hibern8_enter() which is the issue as
link is still in active state due to recovery!
Now ufshcd_uic_hibern8_enter() returns success to ufshcd_gate_work() and
hence it goes ahead with gating the UFS clock while link is still in active
state hence I believe controller would raise UIC error interrupts. But when
we service the interrupt, clocks might have already been disabled!

This change fixes for this by returning failure from
__ufshcd_uic_hibern8_enter() if recovery succeeds as link is still not in
hibern8, upon receiving the error ufshcd_hibern8_enter() would initiate
retry to put the link state back into hibern8.

Change-Id: Ib550fb791fa4c582b8f2d317a7f5f7594acb0872
Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>
This commit is contained in:
Subhash Jadavani 2017-03-24 14:44:01 -07:00 • committed by Gerrit - the friendly Code Review server
parent c5751be200
commit a115b29aaa
1 changed files with 15 additions and 5 deletions
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20
drivers/scsi/ufs/ufshcd.c
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@ -4289,15 +4289,25 @@ static int __ufshcd_uic_hibern8_enter(struct ufs_hba *hba)
* mode hence full reinit is required to move link to HS speeds.
*/
if (ret || hba->full_init_linereset) {
int err;
hba->full_init_linereset = false;
ufshcd_update_error_stats(hba, UFS_ERR_HIBERN8_ENTER);
dev_err(hba->dev, "%s: hibern8 enter failed. ret = %d",
__func__, ret);
/*
* If link recovery fails then return error so that caller
* don't retry the hibern8 enter again.
* If link recovery fails then return error code (-ENOLINK)
* returned ufshcd_link_recovery().
* If link recovery succeeds then return -EAGAIN to attempt
* hibern8 enter retry again.
*/
ret = ufshcd_link_recovery(hba);
err = ufshcd_link_recovery(hba);
if (err) {
dev_err(hba->dev, "%s: link recovery failed", __func__);
ret = err;
} else {
ret = -EAGAIN;
}
} else {
dev_dbg(hba->dev, "%s: Hibern8 Enter at %lld us", __func__,
ktime_to_us(ktime_get()));
@ -4314,8 +4324,8 @@ int ufshcd_uic_hibern8_enter(struct ufs_hba *hba)
ret = __ufshcd_uic_hibern8_enter(hba);
if (!ret)
goto out;
/* Unable to recover the link, so no point proceeding */
if (ret == -ENOLINK)
else if (ret != -EAGAIN)
/* Unable to recover the link, so no point proceeding */
BUG();
}
out: