--- /dev/null
+/*
+ * step_wise.c - A step-by-step Thermal throttling governor
+ *
+ * Copyright (C) 2012 Intel Corp
+ * Copyright (C) 2012 Durgadoss R <durgadoss.r@intel.com>
+ *
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
+ *
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ */
+
+#include <linux/thermal.h>
+#include <trace/events/thermal.h>
+
+#include "thermal_core.h"
+
+/*
+ * If the temperature is higher than a trip point,
+ * a. if the trend is THERMAL_TREND_RAISING, use higher cooling
+ * state for this trip point
+ * b. if the trend is THERMAL_TREND_DROPPING, use lower cooling
+ * state for this trip point
+ * c. if the trend is THERMAL_TREND_RAISE_FULL, use upper limit
+ * for this trip point
+ * d. if the trend is THERMAL_TREND_DROP_FULL, use lower limit
+ * for this trip point
+ * If the temperature is lower than a trip point,
+ * a. if the trend is THERMAL_TREND_RAISING, do nothing
+ * b. if the trend is THERMAL_TREND_DROPPING, use lower cooling
+ * state for this trip point, if the cooling state already
+ * equals lower limit, deactivate the thermal instance
+ * c. if the trend is THERMAL_TREND_RAISE_FULL, do nothing
+ * d. if the trend is THERMAL_TREND_DROP_FULL, use lower limit,
+ * if the cooling state already equals lower limit,
+ * deactivate the thermal instance
+ */
+static unsigned long get_target_state(struct thermal_instance *instance,
+ enum thermal_trend trend, bool throttle)
+{
+ struct thermal_cooling_device *cdev = instance->cdev;
+ unsigned long cur_state;
+ unsigned long next_target;
+
+ /*
+ * We keep this instance the way it is by default.
+ * Otherwise, we use the current state of the
+ * cdev in use to determine the next_target.
+ */
+ cdev->ops->get_cur_state(cdev, &cur_state);
+ next_target = instance->target;
+ dev_dbg(&cdev->device, "cur_state=%ld\n", cur_state);
+
+ switch (trend) {
+ case THERMAL_TREND_RAISING:
+ if (throttle) {
+ next_target = cur_state < instance->upper ?
+ (cur_state + 1) : instance->upper;
+ if (next_target < instance->lower)
+ next_target = instance->lower;
+ }
+ break;
+ case THERMAL_TREND_RAISE_FULL:
+ if (throttle)
+ next_target = instance->upper;
+ break;
+ case THERMAL_TREND_DROPPING:
+ if (cur_state <= instance->lower) {
+ if (!throttle)
+ next_target = THERMAL_NO_TARGET;
+ } else {
+ next_target = cur_state - 1;
+ if (next_target > instance->upper)
+ next_target = instance->upper;
+ }
+ break;
+ case THERMAL_TREND_DROP_FULL:
+ if (cur_state == instance->lower) {
+ if (!throttle)
+ next_target = THERMAL_NO_TARGET;
+ } else
+ next_target = instance->lower;
+ break;
+ default:
+ break;
+ }
+
+ return next_target;
+}
+
+static void update_passive_instance(struct thermal_zone_device *tz,
+ enum thermal_trip_type type, int value)
+{
+ /*
+ * If value is +1, activate a passive instance.
+ * If value is -1, deactivate a passive instance.
+ */
+ if (type == THERMAL_TRIP_PASSIVE || type == THERMAL_TRIPS_NONE)
+ tz->passive += value;
+}
+
+static void thermal_zone_trip_update(struct thermal_zone_device *tz, int trip)
+{
+ long trip_temp;
+ enum thermal_trip_type trip_type;
+ enum thermal_trend trend;
+ struct thermal_instance *instance;
+ bool throttle = false;
+ int old_target;
+
+ if (trip == THERMAL_TRIPS_NONE) {
+ trip_temp = tz->forced_passive;
+ trip_type = THERMAL_TRIPS_NONE;
+ } else {
+ tz->ops->get_trip_temp(tz, trip, &trip_temp);
+ tz->ops->get_trip_type(tz, trip, &trip_type);
+ }
+
+ trend = get_tz_trend(tz, trip);
+
+ if (tz->temperature >= trip_temp) {
+ throttle = true;
+ trace_thermal_zone_trip(tz, trip, trip_type);
+ }
+
+ dev_dbg(&tz->device, "Trip%d[type=%d,temp=%ld]:trend=%d,throttle=%d\n",
+ trip, trip_type, trip_temp, trend, throttle);
+
+ mutex_lock(&tz->lock);
+
+ list_for_each_entry(instance, &tz->thermal_instances, tz_node) {
+ if (instance->trip != trip)
+ continue;
+
+ old_target = instance->target;
+ instance->target = get_target_state(instance, trend, throttle);
+ dev_dbg(&instance->cdev->device, "old_target=%d, target=%d\n",
+ old_target, (int)instance->target);
+
+ if (old_target == instance->target)
+ continue;
+
+ /* Activate a passive thermal instance */
+ if (old_target == THERMAL_NO_TARGET &&
+ instance->target != THERMAL_NO_TARGET)
+ update_passive_instance(tz, trip_type, 1);
+ /* Deactivate a passive thermal instance */
+ else if (old_target != THERMAL_NO_TARGET &&
+ instance->target == THERMAL_NO_TARGET)
+ update_passive_instance(tz, trip_type, -1);
+
+
+ instance->cdev->updated = false; /* cdev needs update */
+ }
+
+ mutex_unlock(&tz->lock);
+}
+
+/**
+ * step_wise_throttle - throttles devices associated with the given zone
+ * @tz - thermal_zone_device
+ * @trip - the trip point
+ * @trip_type - type of the trip point
+ *
+ * Throttling Logic: This uses the trend of the thermal zone to throttle.
+ * If the thermal zone is 'heating up' this throttles all the cooling
+ * devices associated with the zone and its particular trip point, by one
+ * step. If the zone is 'cooling down' it brings back the performance of
+ * the devices by one step.
+ */
+static int step_wise_throttle(struct thermal_zone_device *tz, int trip)
+{
+ struct thermal_instance *instance;
+
+ thermal_zone_trip_update(tz, trip);
+
+ if (tz->forced_passive)
+ thermal_zone_trip_update(tz, THERMAL_TRIPS_NONE);
+
+ mutex_lock(&tz->lock);
+
+ list_for_each_entry(instance, &tz->thermal_instances, tz_node)
+ thermal_cdev_update(instance->cdev);
+
+ mutex_unlock(&tz->lock);
+
+ return 0;
+}
+
+static struct thermal_governor thermal_gov_step_wise = {
+ .name = "step_wise",
+ .throttle = step_wise_throttle,
+};
+
+int thermal_gov_step_wise_register(void)
+{
+ return thermal_register_governor(&thermal_gov_step_wise);
+}
+
+void thermal_gov_step_wise_unregister(void)
+{
+ thermal_unregister_governor(&thermal_gov_step_wise);
+}
Code Review / kvmfornfv.git / blobdiff