This patch attempts to fix a deadlock in ufs while sending SSU.
Recently, blk_queue_enter() added a check to not process requests if the
queue is suspended. That leads to a resume of the associated device which
is suspended. In ufs, that device is ufs device wlun and it's parent is
ufs_hba. This resume tries to resume ufs device wlun which in turn tries
to resume ufs_hba, which is already in the process of suspending, thus
causing a deadlock.
This patch takes care of:
* Suspending the ufs device lun only after all other luns are suspended
* Sending SSU during ufs device wlun suspend
* Clearing uac for rpmb and ufs device wlun
* Not sending commands to the device during host suspend
v4 -> v5:
- Addressed Adrian's comments
* Used the rpmb driver contributed by Adrian
* Runtime-resume the ufs device during suspend to honor spm-lvl
* Unregister the scsi_driver in ufshcd_remove()
* Currently shutdown() puts the ufs device to power-down mode
so, just removed ufshcd_pci_poweroff()
* Quiesce the scsi device during shutdown instead of remove
v3 RFC -> v4:
- Addressed Bart's comments
* Except that I didn't get any checkpatch failures
- Addressed Avri's comments
- Addressed Adrian's comments
* Added a check for deepsleep power mode
* Removed a couple of forward declarations
* Didn't separate the scsi drivers because in rpmb case it just sends uac
in resume and it seemed pretty neat to me.
- Added sysfs changes to resume the devices before accessing
Asutosh Das (2):
scsi: ufs: Enable power management for wlun
ufs: sysfs: Resume the proper scsi device
drivers/scsi/ufs/ufs-qcom.c | 2 +
drivers/scsi/ufs/ufs-sysfs.c | 26 ++-
drivers/scsi/ufs/ufshcd-pci.c | 24 --
drivers/scsi/ufs/ufshcd-pltfrm.c | 29 +++
drivers/scsi/ufs/ufshcd-pltfrm.h | 4 +
drivers/scsi/ufs/ufshcd.c | 491 +++++++++++++++++++++++++++++++--------
drivers/scsi/ufs/ufshcd.h | 5 +
include/trace/events/ufs.h | 20 ++
8 files changed, 469 insertions(+), 132 deletions(-)
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