From: Subhash Jadavani subhashj@codeaurora.org
[ Upstream commit 6d303e4b19d694cdbebf76bcdb51ada664ee953d ]
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() and if failure is encountered, link recovery shall put the link back to the 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.
Link: https://lore.kernel.org/r/1573798172-20534-8-git-send-email-cang@codeaurora.... Reviewed-by: Avri Altman avri.altman@wdc.com Reviewed-by: Bean Huo beanhuo@micron.com Signed-off-by: Subhash Jadavani subhashj@codeaurora.org Signed-off-by: Can Guo cang@codeaurora.org Signed-off-by: Martin K. Petersen martin.petersen@oracle.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/scsi/ufs/ufshcd.c | 19 ++++++++++++++----- 1 file changed, 14 insertions(+), 5 deletions(-)
diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c index 7510d8328d4d..3601e770da16 100644 --- a/drivers/scsi/ufs/ufshcd.c +++ b/drivers/scsi/ufs/ufshcd.c @@ -3875,15 +3875,24 @@ static int __ufshcd_uic_hibern8_enter(struct ufs_hba *hba) ktime_to_us(ktime_sub(ktime_get(), start)), ret);
if (ret) { + int err; + dev_err(hba->dev, "%s: hibern8 enter failed. ret = %d\n", __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 returned from + * ufshcd_link_recovery(). + * If link recovery succeeds then return -EAGAIN to attempt + * hibern8 enter retry again. */ - if (ufshcd_link_recovery(hba)) - ret = -ENOLINK; + err = ufshcd_link_recovery(hba); + if (err) { + dev_err(hba->dev, "%s: link recovery failed", __func__); + ret = err; + } else { + ret = -EAGAIN; + } } else ufshcd_vops_hibern8_notify(hba, UIC_CMD_DME_HIBER_ENTER, POST_CHANGE); @@ -3897,7 +3906,7 @@ static int ufshcd_uic_hibern8_enter(struct ufs_hba *hba)
for (retries = UIC_HIBERN8_ENTER_RETRIES; retries > 0; retries--) { ret = __ufshcd_uic_hibern8_enter(hba); - if (!ret || ret == -ENOLINK) + if (!ret) goto out; } out: