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-rw-r--r--drivers/thermal/gov_fair_share.c118
1 files changed, 118 insertions, 0 deletions
diff --git a/drivers/thermal/gov_fair_share.c b/drivers/thermal/gov_fair_share.c
new file mode 100644
index 000000000..1cfeac16e
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+++ b/drivers/thermal/gov_fair_share.c
@@ -0,0 +1,118 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * fair_share.c - A simple weight based Thermal governor
+ *
+ * Copyright (C) 2012 Intel Corp
+ * Copyright (C) 2012 Durgadoss R <durgadoss.r@intel.com>
+ *
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ *
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ */
+
+#include <linux/thermal.h>
+#include <trace/events/thermal.h>
+
+#include "thermal_core.h"
+
+/**
+ * get_trip_level: - obtains the current trip level for a zone
+ * @tz: thermal zone device
+ */
+static int get_trip_level(struct thermal_zone_device *tz)
+{
+ int count = 0;
+ int trip_temp;
+ enum thermal_trip_type trip_type;
+
+ if (tz->num_trips == 0 || !tz->ops->get_trip_temp)
+ return 0;
+
+ for (count = 0; count < tz->num_trips; count++) {
+ tz->ops->get_trip_temp(tz, count, &trip_temp);
+ if (tz->temperature < trip_temp)
+ break;
+ }
+
+ /*
+ * count > 0 only if temperature is greater than first trip
+ * point, in which case, trip_point = count - 1
+ */
+ if (count > 0) {
+ tz->ops->get_trip_type(tz, count - 1, &trip_type);
+ trace_thermal_zone_trip(tz, count - 1, trip_type);
+ }
+
+ return count;
+}
+
+static long get_target_state(struct thermal_zone_device *tz,
+ struct thermal_cooling_device *cdev, int percentage, int level)
+{
+ return (long)(percentage * level * cdev->max_state) / (100 * tz->num_trips);
+}
+
+/**
+ * fair_share_throttle - throttles devices associated with the given zone
+ * @tz: thermal_zone_device
+ * @trip: trip point index
+ *
+ * Throttling Logic: This uses three parameters to calculate the new
+ * throttle state of the cooling devices associated with the given zone.
+ *
+ * Parameters used for Throttling:
+ * P1. max_state: Maximum throttle state exposed by the cooling device.
+ * P2. percentage[i]/100:
+ * How 'effective' the 'i'th device is, in cooling the given zone.
+ * P3. cur_trip_level/max_no_of_trips:
+ * This describes the extent to which the devices should be throttled.
+ * We do not want to throttle too much when we trip a lower temperature,
+ * whereas the throttling is at full swing if we trip critical levels.
+ * (Heavily assumes the trip points are in ascending order)
+ * new_state of cooling device = P3 * P2 * P1
+ */
+static int fair_share_throttle(struct thermal_zone_device *tz, int trip)
+{
+ struct thermal_instance *instance;
+ int total_weight = 0;
+ int total_instance = 0;
+ int cur_trip_level = get_trip_level(tz);
+
+ lockdep_assert_held(&tz->lock);
+
+ list_for_each_entry(instance, &tz->thermal_instances, tz_node) {
+ if (instance->trip != trip)
+ continue;
+
+ total_weight += instance->weight;
+ total_instance++;
+ }
+
+ list_for_each_entry(instance, &tz->thermal_instances, tz_node) {
+ int percentage;
+ struct thermal_cooling_device *cdev = instance->cdev;
+
+ if (instance->trip != trip)
+ continue;
+
+ if (!total_weight)
+ percentage = 100 / total_instance;
+ else
+ percentage = (instance->weight * 100) / total_weight;
+
+ instance->target = get_target_state(tz, cdev, percentage,
+ cur_trip_level);
+
+ mutex_lock(&cdev->lock);
+ __thermal_cdev_update(cdev);
+ mutex_unlock(&cdev->lock);
+ }
+
+ return 0;
+}
+
+static struct thermal_governor thermal_gov_fair_share = {
+ .name = "fair_share",
+ .throttle = fair_share_throttle,
+};
+THERMAL_GOVERNOR_DECLARE(thermal_gov_fair_share);