TI TFW: omap die governor:fix for staying in PANIC zone

the OMAP4470 more heats up. The patch adds timer which
helps to avoid staying in PANIC zone too long time.

patch realises following algorithm

1. panic_zone_reached == 1;
2. schedule work to be executed after 2s;
3. scheduled work will cancelled if zone will be changed through 2s;
4. after 2s executes scheduled work
5. panic_zone_reached == 2;
6. schedule work to be executed after 4s relative to point 1
7. etc

Change-Id: Ide8bd588b0bf504e2378b5a655fefdeee51c90b1
Signed-off-by: Eugen Mandrenko <ievgen.mandrenko@ti.com>

1 files changed, 31 insertions, 1 deletions

diff --git a/drivers/staging/thermal_framework/governor/omap_die_governor.c b/drivers/staging/thermal_framework/governor/omap_die_governor.c
index ffdacdb..e3f731a 100644
--- a/drivers/staging/thermal_framework/governor/omap_die_governor.c
+++ b/drivers/staging/thermal_framework/governor/omap_die_governor.c
@@ -43,6 +43,7 @@
 #define HYSTERESIS_VALUE 2000
 #define NORMAL_TEMP_MONITORING_RATE 1000
 #define FAST_TEMP_MONITORING_RATE 250
+#define DECREASE_MPU_FREQ_PERIOD 2000
 
 #define OMAP_GRADIENT_SLOPE_4460    348
 #define OMAP_GRADIENT_CONST_4460  -9301
@@ -61,6 +62,7 @@ struct omap_die_governor {
 	void (*update_temp_thresh) (struct thermal_dev *, int min, int max);
 	int report_rate;
 	int panic_zone_reached;
+	int decrease_mpu_freq_period;
 	int cooling_level;
 	int hotspot_temp_upper;
 	int hotspot_temp_lower;
@@ -71,6 +73,7 @@ struct omap_die_governor {
 	int avg_cpu_sensor_temp;
 	int avg_is_valid;
 	struct delayed_work average_cpu_sensor_work;
+	struct delayed_work decrease_mpu_freq_work;
 	int gradient_slope;
 	int gradient_const;
 	int gradient_slope_w_pcb;
@@ -297,6 +300,12 @@ static void omap_fatal_zone(int cpu_temp)
 	kernel_restart(NULL);
 }
 
+static void start_panic_guard(void)
+{
+	schedule_delayed_work(&omap_gov->decrease_mpu_freq_work,
+		msecs_to_jiffies(omap_gov->decrease_mpu_freq_period));
+}
+
 static int omap_cpu_thermal_manager(struct list_head *cooling_list, int temp)
 {
 	int cpu_temp, zone = NO_ACTION;
@@ -358,13 +367,29 @@ static int omap_cpu_thermal_manager(struct list_head *cooling_list, int temp)
 		zone = ALERT_ZONE;
 	}
 
-	if (zone != NO_ACTION)
+	if (zone != NO_ACTION) {
+		if (omap_gov->panic_zone_reached)
+			start_panic_guard();
+		else
+			cancel_delayed_work(&omap_gov->decrease_mpu_freq_work);
 		omap_enter_zone(&omap_thermal_zones[zone - 1],
 				set_cooling_level, cooling_list, cpu_temp);
+	}
 
 	return zone;
 }
 
+static void decrease_mpu_freq_fn(struct work_struct *work)
+{
+	struct omap_die_governor *omap_gov;
+
+	omap_gov = container_of(work, struct omap_die_governor,
+				decrease_mpu_freq_work.work);
+
+	omap_gov->sensor_temp = thermal_request_temp(omap_gov->temp_sensor);
+	thermal_sensor_set_temp(omap_gov->temp_sensor);
+}
+
 /*
  * Make an average of the OMAP on-die temperature
  * this is helpful to handle burst activity of OMAP when extrapolating
@@ -451,6 +476,7 @@ static int omap_die_pm_notifier_cb(struct notifier_block *notifier,
 	switch (pm_event) {
 	case PM_SUSPEND_PREPARE:
 		cancel_delayed_work_sync(&omap_gov->average_cpu_sensor_work);
+		cancel_delayed_work(&omap_gov->decrease_mpu_freq_work);
 		break;
 	case PM_POST_SUSPEND:
 		schedule_work(&omap_gov->average_cpu_sensor_work.work);
@@ -511,8 +537,11 @@ static int __init omap_die_governor_init(void)
 	/* Init delayed work to average on-die temperature */
 	INIT_DELAYED_WORK(&omap_gov->average_cpu_sensor_work,
 			  average_cpu_sensor_delayed_work_fn);
+	INIT_DELAYED_WORK(&omap_gov->decrease_mpu_freq_work,
+			  decrease_mpu_freq_fn);
 
 	omap_gov->average_period = NORMAL_TEMP_MONITORING_RATE;
+	omap_gov->decrease_mpu_freq_period = DECREASE_MPU_FREQ_PERIOD;
 	omap_gov->avg_is_valid = 0;
 
 	if (register_pm_notifier(&omap_die_pm_notifier))
@@ -527,6 +556,7 @@ static int __init omap_die_governor_init(void)
 static void __exit omap_die_governor_exit(void)
 {
 	cancel_delayed_work_sync(&omap_gov->average_cpu_sensor_work);
+	cancel_delayed_work_sync(&omap_gov->decrease_mpu_freq_work);
 	thermal_governor_dev_unregister(therm_fw);
 	kfree(therm_fw);
 	kfree(omap_gov);