Commit a115b29a authored Mar 24, 2017 by Subhash Jadavani Committed by Gerrit - the friendly Code Review server Apr 05, 2017

scsi: ufs: fix error handing during hibern8 enter



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>

parent c5751be2

drivers/scsi/ufs/ufshcd.c

+15 −5

Original line number	Diff line number	Diff line
		@@ -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;
		else if (ret != -EAGAIN)
		/* Unable to recover the link, so no point proceeding */
		if (ret == -ENOLINK)
		BUG();
		}
		out: