[PATCH v6 0/2] Enable power management for ufs wlun

[Asutosh Das]

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

v5 -> v6:
- Addressed Adrian's comments
  * Added complete() cb
  * Added suspend_prepare() and complete() to all drivers
  * Moved suspend_prepare() and complete() to ufshcd
  * .poweroff() uses ufhcd_wl_poweroff()
  * Removed several forward declarations
  * Moved scsi_register_driver() to ufshcd_core_init()

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/cdns-pltfrm.c     |   2 +
 drivers/scsi/ufs/tc-dwc-g210-pci.c |   2 +
 drivers/scsi/ufs/ufs-exynos.c      |   2 +
 drivers/scsi/ufs/ufs-hisi.c        |   2 +
 drivers/scsi/ufs/ufs-mediatek.c    |   2 +
 drivers/scsi/ufs/ufs-qcom.c        |   2 +
 drivers/scsi/ufs/ufs-sysfs.c       |  26 +-
 drivers/scsi/ufs/ufshcd-pci.c      |  26 +-
 drivers/scsi/ufs/ufshcd.c          | 530 ++++++++++++++++++++++++++++++-------
 drivers/scsi/ufs/ufshcd.h          |   7 +
 include/trace/events/ufs.h         |  20 ++
 11 files changed, 489 insertions(+), 132 deletions(-)

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