[PATCH 7/8] scsi: ufs: Add a PM notifier

[Bart Van Assche <bvanassche@acm.org>]

Add a PM notifier to track whether or not the system is suspending. This
information will be used in a later patch to fix a deadlock between the
SCSI error handler and the suspend code.

Signed-off-by: Bart Van Assche <bvanassche@acm.org>
---
 drivers/ufs/core/ufshcd.c | 24 ++++++++++++++++++++++++
 include/ufs/ufshcd.h      |  7 ++++++-
 2 files changed, 30 insertions(+), 1 deletion(-)

diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
index d7453f788d0d..abeb120b12eb 100644
--- a/drivers/ufs/core/ufshcd.c
+++ b/drivers/ufs/core/ufshcd.c
@@ -9246,6 +9246,25 @@ static int ufshcd_wl_runtime_resume(struct device *dev)
 }
 #endif
 
+static int ufshcd_pm_cb(struct notifier_block *nb, unsigned long action,
+			void *data)
+{
+	struct ufs_hba *hba = container_of(nb, typeof(*hba), pm_nb);
+
+	switch (action) {
+	case PM_HIBERNATION_PREPARE:
+	case PM_SUSPEND_PREPARE:
+		hba->system_suspending = true;
+		break;
+	case PM_POST_RESTORE:
+	case PM_POST_SUSPEND:
+		hba->system_suspending = false;
+		break;
+	}
+
+	return 0;
+}
+
 #ifdef CONFIG_PM_SLEEP
 static int ufshcd_wl_suspend(struct device *dev)
 {
@@ -9534,6 +9553,7 @@ EXPORT_SYMBOL(ufshcd_shutdown);
  */
 void ufshcd_remove(struct ufs_hba *hba)
 {
+	unregister_pm_notifier(&hba->pm_nb);
 	if (hba->ufs_device_wlun)
 		ufshcd_rpm_get_sync(hba);
 	ufs_hwmon_remove(hba);
@@ -9832,7 +9852,11 @@ int ufshcd_init(struct ufs_hba *hba, void __iomem *mmio_base, unsigned int irq)
 	async_schedule(ufshcd_async_scan, hba);
 	ufs_sysfs_add_nodes(hba->dev);
 
+	hba->pm_nb = (struct notifier_block){ .notifier_call = ufshcd_pm_cb };
+	register_pm_notifier(&hba->pm_nb);
+
 	device_enable_async_suspend(dev);
+
 	return 0;
 
 free_tmf_queue:
diff --git a/include/ufs/ufshcd.h b/include/ufs/ufshcd.h
index 24c97e0772bb..9bc48c13006f 100644
--- a/include/ufs/ufshcd.h
+++ b/include/ufs/ufshcd.h
@@ -802,7 +802,10 @@ struct ufs_hba_monitor {
  * @caps: bitmask with information about UFS controller capabilities
  * @devfreq: frequency scaling information owned by the devfreq core
  * @clk_scaling: frequency scaling information owned by the UFS driver
- * @is_sys_suspended: whether or not the entire system has been suspended
+ * @system_suspending: system suspend has been started and system resume has
+ *	not yet finished.
+ * @is_sys_suspended: UFS device has been suspended because of system suspend
+ * @pm_nb: power management notifier block
  * @urgent_bkops_lvl: keeps track of urgent bkops level for device
  * @is_urgent_bkops_lvl_checked: keeps track if the urgent bkops level for
  *  device is known or not.
@@ -943,7 +946,9 @@ struct ufs_hba {
 
 	struct devfreq *devfreq;
 	struct ufs_clk_scaling clk_scaling;
+	bool system_suspending;
 	bool is_sys_suspended;
+	struct notifier_block pm_nb;
 
 	enum bkops_status urgent_bkops_lvl;
 	bool is_urgent_bkops_lvl_checked;