scsi: ufs: Fix error handing during hibern8 enter

commit 6d303e4b upstream.

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.org


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: Paul Gortmaker <paul.gortmaker@windriver.com>