1 files changed, 119 insertions, 0 deletions
diff --git a/drivers/thermal/gov_fair_share.c b/drivers/thermal/gov_fair_share.c
new file mode 100644
index 000000000000..4643be4f941d
--- /dev/null
+++ b/drivers/thermal/gov_fair_share.c
@@ -0,0 +1,119 @@
+// 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 "thermal_trace.h"
+
+#include "thermal_core.h"
+
+static int get_trip_level(struct thermal_zone_device *tz)
+{
+	const struct thermal_trip_desc *level_td = NULL;
+	const struct thermal_trip_desc *td;
+	int trip_level = -1;
+
+	for_each_trip_desc(tz, td) {
+		if (td->threshold > tz->temperature)
+			continue;
+
+		trip_level++;
+
+		if (!level_td || td->threshold > level_td->threshold)
+			level_td = td;
+	}
+
+	/*  Bail out if the temperature is not greater than any trips. */
+	if (trip_level < 0)
+		return 0;
+
+	trace_thermal_zone_trip(tz, thermal_zone_trip_id(tz, &level_td->trip),
+				level_td->trip.type);
+
+	return trip_level;
+}
+
+/**
+ * fair_share_throttle - throttles devices associated with the given zone
+ * @tz: thermal_zone_device
+ * @td: trip point descriptor
+ * @trip_level: number of trips crossed by the zone temperature
+ *
+ * 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. weight[i]/total_weight:
+ *	How 'effective' the 'i'th device is, in cooling the given zone.
+ * P3. 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.
+ * new_state of cooling device = P3 * P2 * P1
+ */
+static void fair_share_throttle(struct thermal_zone_device *tz,
+				const struct thermal_trip_desc *td,
+				int trip_level)
+{
+	struct thermal_instance *instance;
+	int total_weight = 0;
+	int nr_instances = 0;
+
+	list_for_each_entry(instance, &td->thermal_instances, trip_node) {
+		total_weight += instance->weight;
+		nr_instances++;
+	}
+
+	list_for_each_entry(instance, &td->thermal_instances, trip_node) {
+		struct thermal_cooling_device *cdev = instance->cdev;
+		u64 dividend;
+		u32 divisor;
+
+		dividend = trip_level;
+		dividend *= cdev->max_state;
+		divisor = tz->num_trips;
+		if (total_weight) {
+			dividend *= instance->weight;
+			divisor *= total_weight;
+		} else {
+			divisor *= nr_instances;
+		}
+		instance->target = div_u64(dividend, divisor);
+
+		thermal_cdev_update_nocheck(cdev);
+	}
+}
+
+static void fair_share_manage(struct thermal_zone_device *tz)
+{
+	int trip_level = get_trip_level(tz);
+	const struct thermal_trip_desc *td;
+
+	lockdep_assert_held(&tz->lock);
+
+	for_each_trip_desc(tz, td) {
+		const struct thermal_trip *trip = &td->trip;
+
+		if (trip->temperature == THERMAL_TEMP_INVALID ||
+		    trip->type == THERMAL_TRIP_CRITICAL ||
+		    trip->type == THERMAL_TRIP_HOT)
+			continue;
+
+		fair_share_throttle(tz, td, trip_level);
+	}
+}
+
+static struct thermal_governor thermal_gov_fair_share = {
+	.name	= "fair_share",
+	.manage	= fair_share_manage,
+};
+THERMAL_GOVERNOR_DECLARE(thermal_gov_fair_share);