msm-tsens: Reschedule work instead of causing uninterruptible sleep

The tsens_poll work causes uninterruptible sleep on the UI
thread and thus blocks other tasks from running due to the
msleep call.

To avoid this condition, we introduce a variable to hold
the staging state of the critical polling and reschedule the
work itself to be executed again after the same
duration as the msleep.

Additionally we switch the currently unused wq to
a singlethreaded wq and queue the tsens work onto
that wq.

Change-Id: I0bf48837310decd035d35ac78aa7d51614032b36
Signed-off-by: Alex Naidis <alex.naidis@linux.com>
Signed-off-by: Ícaro Hoff <icarohoff@gmail.com>

drivers/thermal/msm-tsens.c

@@ -867,6 +867,7 @@ struct tsens_tm_device {
 	u64				qtimer_val_last_detection_interrupt;
 	u64				qtimer_val_last_polling_check;
 	bool				tsens_critical_poll;
+	bool				tsens_critical_poll_state;
 	struct tsens_tm_device_sensor	sensor[0];
 };
 
@@ -2010,7 +2011,7 @@ static void tsens_poll(struct work_struct *work)
 	unsigned int debug_id = 0, cntrl_id = 0;
 	uint32_t r1, r2, r3, r4, offset = 0, idx = 0;
 	unsigned long temp, flags;
-	unsigned int status, int_mask, int_mask_val;
+	unsigned int status, int_mask, int_mask_val, resched_ms;
 	void __iomem *srot_addr;
 	void __iomem *controller_id_addr;
 	void __iomem *debug_id_addr;
@@ -2034,6 +2035,10 @@ static void tsens_poll(struct work_struct *work)
 	/* Sensor 0 on either of the controllers */
 	mask = 0;
 
+	if (tmdev->tsens_critical_poll_state) {
+		goto critical_poll;
+	}
+
 	reinit_completion(&tmdev->tsens_rslt_completion);
 
 	temp &= TSENS_TM_SN_CRITICAL_THRESHOLD_MASK;
@@ -2069,8 +2074,12 @@ static void tsens_poll(struct work_struct *work)
 	}
 	spin_unlock_irqrestore(&tmdev->tsens_crit_lock, flags);
 
-	if (tmdev->tsens_critical_poll) {
-		msleep(TSENS_DEBUG_POLL_MS);
+critical_poll:
+	if (tmdev->tsens_critical_poll && !tmdev->tsens_critical_poll_state) {
+		tmdev->tsens_critical_poll_state = true;
+		goto re_schedule;
+	} else if (tmdev->tsens_critical_poll) {
+		tmdev->tsens_critical_poll_state = false;
 		sensor_status_addr = TSENS_TM_SN_STATUS(tmdev->tsens_addr);
 
 		spin_lock_irqsave(&tmdev->tsens_crit_lock, flags);
@@ -2230,9 +2239,11 @@ static void tsens_poll(struct work_struct *work)
 	}
 
 re_schedule:
-
-	schedule_delayed_work(&tmdev->tsens_critical_poll_test,
-			msecs_to_jiffies(tsens_sec_to_msec_value));
+	resched_ms = tmdev->tsens_critical_poll_state
+		? TSENS_DEBUG_POLL_MS : tsens_sec_to_msec_value;
+	queue_delayed_work(tmdev->tsens_critical_wq,
+		&tmdev->tsens_critical_poll_test,
+		msecs_to_jiffies(resched_ms));
 }
 
 int tsens_mtc_reset_history_counter(unsigned int zone)
@@ -5744,8 +5755,8 @@ static int tsens_tm_probe(struct platform_device *pdev)
 
 	tmdev->pdev = pdev;
 
-	tmdev->tsens_critical_wq = alloc_workqueue("tsens_critical_wq",
-							WQ_HIGHPRI, 0);
+	tmdev->tsens_critical_wq = create_singlethread_workqueue("tsens_critical_wq");
+
 	if (!tmdev->tsens_critical_wq) {
 		rc = -ENOMEM;
 		goto fail;
@@ -5770,6 +5781,7 @@ static int tsens_tm_probe(struct platform_device *pdev)
 	spin_lock_init(&tmdev->tsens_upp_low_lock);
 	spin_lock_init(&tmdev->tsens_debug_lock);
 
+	tmdev->tsens_critical_poll_state = false;
 	tmdev->is_ready = true;
 
 	list_add_tail(&tmdev->list, &tsens_device_list);
@@ -5938,7 +5950,8 @@ static int tsens_thermal_zone_register(struct tsens_tm_device *tmdev)
 		if (tsens_poll_check) {
 			INIT_DEFERRABLE_WORK(&tmdev->tsens_critical_poll_test,
 								tsens_poll);
-			schedule_delayed_work(&tmdev->tsens_critical_poll_test,
+			queue_delayed_work(tmdev->tsens_critical_wq,
+				&tmdev->tsens_critical_poll_test,
 				msecs_to_jiffies(tsens_sec_to_msec_value));
 			init_completion(&tmdev->tsens_rslt_completion);
 			tmdev->tsens_critical_poll = true;