Thermal: initialize thermal zone device correctly

After thermal zone device registered, as we have not read any
temperature before, thus tz->temperature should not be 0,
which actually means 0C, and thermal trend is not available.
In this case, we need specially handling for the first
thermal_zone_device_update().

Both thermal core framework and step_wise governor is
enhanced to handle this. And since the step_wise governor
is the only one that uses trends, so it's the only thermal
governor that needs to be updated.

CC: <stable@vger.kernel.org> #3.18+
Tested-by: Manuel Krause <manuelkrause@netscape.net>
Tested-by: szegad <szegadlo@poczta.onet.pl>
Tested-by: prash <prash.n.rao@gmail.com>
Tested-by: amish <ammdispose-arch@yahoo.com>
Tested-by: Matthias <morpheusxyz123@yahoo.de>
Reviewed-by: Javi Merino <javi.merino@arm.com>
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Chen Yu <yu.c.chen@intel.com>

4 files changed, 36 insertions, 4 deletions

diff --git a/drivers/thermal/step_wise.c b/drivers/thermal/step_wise.c
index 2f9f7086ac3d..ea9366ad3e6b 100644
--- a/drivers/thermal/step_wise.c
+++ b/drivers/thermal/step_wise.c
@@ -63,6 +63,19 @@ static unsigned long get_target_state(struct thermal_instance *instance,
         next_target = instance->target;
         dev_dbg(&cdev->device, "cur_state=%ld\n", cur_state);
 
+        if (!instance->initialized) {
+                if (throttle) {
+                        next_target = (cur_state + 1) >= instance->upper ?
+                                        instance->upper :
+                                        ((cur_state + 1) < instance->lower ?
+                                        instance->lower : (cur_state + 1));
+                } else {
+                        next_target = THERMAL_NO_TARGET;
+                }
+
+                return next_target;
+        }
+
         switch (trend) {
         case THERMAL_TREND_RAISING:
                 if (throttle) {
@@ -149,7 +162,7 @@ static void thermal_zone_trip_update(struct thermal_zone_device *tz, int trip)
                 dev_dbg(&instance->cdev->device, "old_target=%d, target=%d\n",
                                         old_target, (int)instance->target);
 
-                if (old_target == instance->target)
+                if (instance->initialized && old_target == instance->target)
                         continue;
 
                 /* Activate a passive thermal instance */
@@ -161,7 +174,7 @@ static void thermal_zone_trip_update(struct thermal_zone_device *tz, int trip)
                         instance->target == THERMAL_NO_TARGET)
                         update_passive_instance(tz, trip_type, -1);
 
-
+                instance->initialized = true;
                 instance->cdev->updated = false; /* cdev needs update */
         }
 
diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c
index d9e525cc9c1c..682bc1ef9c37 100644
--- a/drivers/thermal/thermal_core.c
+++ b/drivers/thermal/thermal_core.c
@@ -532,8 +532,22 @@ static void update_temperature(struct thermal_zone_device *tz)
         mutex_unlock(&tz->lock);
 
         trace_thermal_temperature(tz);
-        dev_dbg(&tz->device, "last_temperature=%d, current_temperature=%d\n",
-                                tz->last_temperature, tz->temperature);
+        if (tz->last_temperature == THERMAL_TEMP_INVALID)
+                dev_dbg(&tz->device, "last_temperature N/A, current_temperature=%d\n",
+                        tz->temperature);
+        else
+                dev_dbg(&tz->device, "last_temperature=%d, current_temperature=%d\n",
+                        tz->last_temperature, tz->temperature);
+}
+
+static void thermal_zone_device_reset(struct thermal_zone_device *tz)
+{
+        struct thermal_instance *pos;
+
+        tz->temperature = THERMAL_TEMP_INVALID;
+        tz->passive = 0;
+        list_for_each_entry(pos, &tz->thermal_instances, tz_node)
+                pos->initialized = false;
 }
 
 void thermal_zone_device_update(struct thermal_zone_device *tz)
@@ -1900,6 +1914,7 @@ struct thermal_zone_device *thermal_zone_device_register(const char *type,
 
         INIT_DELAYED_WORK(&(tz->poll_queue), thermal_zone_device_check);
 
+        thermal_zone_device_reset(tz);
         thermal_zone_device_update(tz);
 
         return tz;
diff --git a/drivers/thermal/thermal_core.h b/drivers/thermal/thermal_core.h
index d7ac1fccd659..749d41abfbab 100644
--- a/drivers/thermal/thermal_core.h
+++ b/drivers/thermal/thermal_core.h
@@ -41,6 +41,7 @@ struct thermal_instance {
         struct thermal_zone_device *tz;
         struct thermal_cooling_device *cdev;
         int trip;
+        bool initialized;
         unsigned long upper;    /* Highest cooling state for this trip point */
         unsigned long lower;    /* Lowest cooling state for this trip point */
         unsigned long target;   /* expected cooling state */
diff --git a/include/linux/thermal.h b/include/linux/thermal.h
index 613c29bd6baf..103fcbe6bdaf 100644
--- a/include/linux/thermal.h
+++ b/include/linux/thermal.h
@@ -43,6 +43,9 @@
 /* Default weight of a bound cooling device */
 #define THERMAL_WEIGHT_DEFAULT 0
 
+/* use value, which < 0K, to indicate an invalid/uninitialized temperature */
+#define THERMAL_TEMP_INVALID    -274000
+
 /* Unit conversion macros */
 #define DECI_KELVIN_TO_CELSIUS(t)       ({                      \
         long _t = (t);                                          \