[PATCH v14 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

v13 -> v14:
- Addressed Adrian's comments
  * Rebased it on top of scsi-next
  * Added scsi_autopm_[get/put] to ufs_debugfs[get/put]_user_access()
  * Resume the device in ufshcd_remove()
  * Unregister ufs_rpmb_wlun before ufs_dev_wlun
  * hba->shutting_down moved to ufshcd_wl_shutdown()

v12 -> v13:
- Addressed Adrian's comments
  * Paired pm_runtime_get_noresume() with pm_runtime_put()
  * no rpm_autosuspend for ufs device wlun
  * Moved runtime-pm init functionality to ufshcd_wl_probe()
- Addressed Bart's comments
  * Expanded abbrevs in commit message

v11 -> v12:
- Addressed Adrian's comments
  * Fixed ahit for Mediatek driver
  * Fixed error handling in ufshcd_core_init()
  * Tested this patch and the issue is still seen.

v10 -> v11:
- Fixed supplier suspending before consumer race
- Addressed Adrian's comments
  * Added proper resume/suspend cb to ufshcd_auto_hibern8_update()
  * Cosmetic changes to ufshcd-pci.c
  * Cleaned up ufshcd_system_suspend()
  * Added ufshcd_debugfs_eh_exit to ufshcd_core_init()

v9 -> v10:
- Addressed Adrian's comments
  * Moved suspend/resume vops to __ufshcd_wl_[suspend/resume]()
  * Added correct resume in ufs_bsg

v8 -> v9:
- Addressed Adrian's comments
  * Moved link transition to __ufshcd_wl_[suspend/resume]()
  * Fixed the other minor comments

v7 -> v8:
- Addressed Adrian's comments
  * Removed separate autosuspend delay for ufs-device lun
  * Fixed the ee handler getting scheduled during pm
  * Always runtime resume in suspend_prepare()
  * Added CONFIG_PM_SLEEP where needed
  
v6 -> v7:
  * Resume the ufs device before shutting it down

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-debugfs.c     |   6 +-
 drivers/scsi/ufs/ufs-debugfs.h     |   2 +-
 drivers/scsi/ufs/ufs-exynos.c      |   2 +
 drivers/scsi/ufs/ufs-hisi.c        |   2 +
 drivers/scsi/ufs/ufs-mediatek.c    |  12 +-
 drivers/scsi/ufs/ufs-qcom.c        |   2 +
 drivers/scsi/ufs/ufs-sysfs.c       |  30 +-
 drivers/scsi/ufs/ufs_bsg.c         |   6 +-
 drivers/scsi/ufs/ufshcd-pci.c      |  36 +--
 drivers/scsi/ufs/ufshcd.c          | 636 ++++++++++++++++++++++++++-----------
 drivers/scsi/ufs/ufshcd.h          |   6 +
 include/trace/events/ufs.h         |  20 ++
 14 files changed, 521 insertions(+), 243 deletions(-)

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