[PATCH v10 0/2] Enable power management for ufs wlun

Asutosh Das
2021-03-03T01:21:35Z

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

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-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 | 30 +-
drivers/scsi/ufs/ufs_bsg.c | 6 +-
drivers/scsi/ufs/ufshcd-pci.c | 32 +-
drivers/scsi/ufs/ufshcd.c | 583 +++++++++++++++++++++++++++----------
drivers/scsi/ufs/ufshcd.h | 7 +
include/trace/events/ufs.h | 20 ++
12 files changed, 495 insertions(+), 195 deletions(-)

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