Merge branch 'mhi-immutable' of...

Merge branch 'mhi-immutable' of git://git.kernel.org/pub/scm/linux/kernel/git/mani/mhi into ath-next

This is needed for patch 'wifi: ath11k: support hibernation'.

drivers/bus/mhi/host/internal.h

@@ -80,6 +80,7 @@ enum dev_st_transition {
 	DEV_ST_TRANSITION_FP,
 	DEV_ST_TRANSITION_SYS_ERR,
 	DEV_ST_TRANSITION_DISABLE,
+	DEV_ST_TRANSITION_DISABLE_DESTROY_DEVICE,
 	DEV_ST_TRANSITION_MAX,
 };
 
@@ -90,7 +91,8 @@ enum dev_st_transition {
 	dev_st_trans(MISSION_MODE,	"MISSION MODE")		\
 	dev_st_trans(FP,		"FLASH PROGRAMMER")	\
 	dev_st_trans(SYS_ERR,		"SYS ERROR")		\
-	dev_st_trans_end(DISABLE,	"DISABLE")
+	dev_st_trans(DISABLE,		"DISABLE")		\
+	dev_st_trans_end(DISABLE_DESTROY_DEVICE, "DISABLE (DESTROY DEVICE)")
 
 extern const char * const dev_state_tran_str[DEV_ST_TRANSITION_MAX];
 #define TO_DEV_STATE_TRANS_STR(state) (((state) >= DEV_ST_TRANSITION_MAX) ? \

drivers/bus/mhi/host/pm.c

@@ -468,7 +468,8 @@ static int mhi_pm_mission_mode_transition(struct mhi_controller *mhi_cntrl)
 }
 
 /* Handle shutdown transitions */
-static void mhi_pm_disable_transition(struct mhi_controller *mhi_cntrl)
+static void mhi_pm_disable_transition(struct mhi_controller *mhi_cntrl,
+				      bool destroy_device)
 {
 	enum mhi_pm_state cur_state;
 	struct mhi_event *mhi_event;
@@ -530,8 +531,16 @@ static void mhi_pm_disable_transition(struct mhi_controller *mhi_cntrl)
 	dev_dbg(dev, "Waiting for all pending threads to complete\n");
 	wake_up_all(&mhi_cntrl->state_event);
 
-	dev_dbg(dev, "Reset all active channels and remove MHI devices\n");
-	device_for_each_child(&mhi_cntrl->mhi_dev->dev, NULL, mhi_destroy_device);
+	/*
+	 * Only destroy the 'struct device' for channels if indicated by the
+	 * 'destroy_device' flag. Because, during system suspend or hibernation
+	 * state, there is no need to destroy the 'struct device' as the endpoint
+	 * device would still be physically attached to the machine.
+	 */
+	if (destroy_device) {
+		dev_dbg(dev, "Reset all active channels and remove MHI devices\n");
+		device_for_each_child(&mhi_cntrl->mhi_dev->dev, NULL, mhi_destroy_device);
+	}
 
 	mutex_lock(&mhi_cntrl->pm_mutex);
 
@@ -821,7 +830,10 @@ void mhi_pm_st_worker(struct work_struct *work)
 			mhi_pm_sys_error_transition(mhi_cntrl);
 			break;
 		case DEV_ST_TRANSITION_DISABLE:
-			mhi_pm_disable_transition(mhi_cntrl);
+			mhi_pm_disable_transition(mhi_cntrl, false);
+			break;
+		case DEV_ST_TRANSITION_DISABLE_DESTROY_DEVICE:
+			mhi_pm_disable_transition(mhi_cntrl, true);
 			break;
 		default:
 			break;
@@ -1175,7 +1187,8 @@ int mhi_async_power_up(struct mhi_controller *mhi_cntrl)
 }
 EXPORT_SYMBOL_GPL(mhi_async_power_up);
 
-void mhi_power_down(struct mhi_controller *mhi_cntrl, bool graceful)
+static void __mhi_power_down(struct mhi_controller *mhi_cntrl, bool graceful,
+			     bool destroy_device)
 {
 	enum mhi_pm_state cur_state, transition_state;
 	struct device *dev = &mhi_cntrl->mhi_dev->dev;
@@ -1211,15 +1224,32 @@ void mhi_power_down(struct mhi_controller *mhi_cntrl, bool graceful)
 	write_unlock_irq(&mhi_cntrl->pm_lock);
 	mutex_unlock(&mhi_cntrl->pm_mutex);
 
-	mhi_queue_state_transition(mhi_cntrl, DEV_ST_TRANSITION_DISABLE);
+	if (destroy_device)
+		mhi_queue_state_transition(mhi_cntrl,
+					   DEV_ST_TRANSITION_DISABLE_DESTROY_DEVICE);
+	else
+		mhi_queue_state_transition(mhi_cntrl,
+					   DEV_ST_TRANSITION_DISABLE);
 
 	/* Wait for shutdown to complete */
 	flush_work(&mhi_cntrl->st_worker);
 
 	disable_irq(mhi_cntrl->irq[0]);
 }
+
+void mhi_power_down(struct mhi_controller *mhi_cntrl, bool graceful)
+{
+	__mhi_power_down(mhi_cntrl, graceful, true);
+}
 EXPORT_SYMBOL_GPL(mhi_power_down);
 
+void mhi_power_down_keep_dev(struct mhi_controller *mhi_cntrl,
+			       bool graceful)
+{
+	__mhi_power_down(mhi_cntrl, graceful, false);
+}
+EXPORT_SYMBOL_GPL(mhi_power_down_keep_dev);
+
 int mhi_sync_power_up(struct mhi_controller *mhi_cntrl)
 {
 	int ret = mhi_async_power_up(mhi_cntrl);

include/linux/mhi.h

@@ -630,12 +630,28 @@ int mhi_async_power_up(struct mhi_controller *mhi_cntrl);
 int mhi_sync_power_up(struct mhi_controller *mhi_cntrl);
 
 /**
- * mhi_power_down - Start MHI power down sequence
+ * mhi_power_down - Power down the MHI device and also destroy the
+ *                  'struct device' for the channels associated with it.
+ *                  See also mhi_power_down_keep_dev() which is a variant
+ *                  of this API that keeps the 'struct device' for channels
+ *                  (useful during suspend/hibernation).
  * @mhi_cntrl: MHI controller
  * @graceful: Link is still accessible, so do a graceful shutdown process
  */
 void mhi_power_down(struct mhi_controller *mhi_cntrl, bool graceful);
 
+/**
+ * mhi_power_down_keep_dev - Power down the MHI device but keep the 'struct
+ *                           device' for the channels associated with it.
+ *                           This is a variant of 'mhi_power_down()' and
+ *                           useful in scenarios such as suspend/hibernation
+ *                           where destroying of the 'struct device' is not
+ *                           needed.
+ * @mhi_cntrl: MHI controller
+ * @graceful: Link is still accessible, so do a graceful shutdown process
+ */
+void mhi_power_down_keep_dev(struct mhi_controller *mhi_cntrl, bool graceful);
+
 /**
  * mhi_unprepare_after_power_down - Free any allocated memory after power down
  * @mhi_cntrl: MHI controller