[PATCH 1/7] thermal: stats: track time each dev changes due to tz

[Eduardo Valentin <evalenti@kernel.org>]

From: Eduardo Valentin <eduval@amazon.com>

This patch improves the current cooling device
statistics by adding a new file under
cdev/stats/time_in_thermal_zone_ms
to represent the time in milliseconds
that the cooling device was driven by each
associated thermal zone.

The file format is:
thermal_zone: <type> <time_in_ms>

Samples:
$ cat /sys/class/thermal/cooling_device0/stats/time_in_thermal_zone_ms
thermal_zone: amb0	117496

Cc: "Rafael J. Wysocki" <rafael@kernel.org> (supporter:THERMAL)
Cc: Daniel Lezcano <daniel.lezcano@linaro.org> (supporter:THERMAL)
Cc: Amit Kucheria <amitk@kernel.org> (reviewer:THERMAL)
Cc: Zhang Rui <rui.zhang@intel.com> (reviewer:THERMAL)
Cc: Jonathan Corbet <corbet@lwn.net> (maintainer:DOCUMENTATION)
Cc: linux-pm@vger.kernel.org (open list:THERMAL)
Cc: linux-doc@vger.kernel.org (open list:DOCUMENTATION)
Cc: linux-kernel@vger.kernel.org (open list)

Signed-off-by: Eduardo Valentin <eduval@amazon.com>
---
 .../driver-api/thermal/sysfs-api.rst          |   2 +
 drivers/thermal/thermal_core.c                |   2 +-
 drivers/thermal/thermal_core.h                |   5 +
 drivers/thermal/thermal_helpers.c             |  11 +-
 drivers/thermal/thermal_sysfs.c               | 128 +++++++++++++++++-
 5 files changed, 139 insertions(+), 9 deletions(-)

diff --git a/Documentation/driver-api/thermal/sysfs-api.rst b/Documentation/driver-api/thermal/sysfs-api.rst
index 6c1175c6afba..caa50d61a5bc 100644
--- a/Documentation/driver-api/thermal/sysfs-api.rst
+++ b/Documentation/driver-api/thermal/sysfs-api.rst
@@ -367,6 +367,8 @@ Thermal cooling device sys I/F, created once it's registered::
     |---stats/time_in_state_ms:	Time (msec) spent in various cooling states
     |---stats/total_trans:	Total number of times cooling state is changed
     |---stats/trans_table:	Cooling state transition table
+    |---stats/time_in_thermal_zone_ms:	Time that this cooling device was driven
+                                each associated thermal zone.
 
 
 Then next two dynamic attributes are created/removed in pairs. They represent
diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c
index 842f678c1c3e..4bb77af6a6f4 100644
--- a/drivers/thermal/thermal_core.c
+++ b/drivers/thermal/thermal_core.c
@@ -1078,7 +1078,7 @@ void thermal_cooling_device_update(struct thermal_cooling_device *cdev)
 	if (cdev->ops->get_cur_state(cdev, &state) || state > cdev->max_state)
 		goto unlock;
 
-	thermal_cooling_device_stats_update(cdev, state);
+	thermal_cooling_device_stats_update(cdev, NULL, state);
 
 unlock:
 	mutex_unlock(&cdev->lock);
diff --git a/drivers/thermal/thermal_core.h b/drivers/thermal/thermal_core.h
index 3d4a787c6b28..3cce60c6e065 100644
--- a/drivers/thermal/thermal_core.h
+++ b/drivers/thermal/thermal_core.h
@@ -102,6 +102,9 @@ struct thermal_instance {
 	struct list_head cdev_node; /* node in cdev->thermal_instances */
 	unsigned int weight; /* The weight of the cooling device */
 	bool upper_no_limit;
+#if IS_ENABLED(CONFIG_THERMAL_STATISTICS)
+	ktime_t time_in; /* time spent in this instance */
+#endif
 };
 
 #define to_thermal_zone(_dev) \
@@ -137,10 +140,12 @@ ssize_t weight_store(struct device *, struct device_attribute *, const char *,
 
 #ifdef CONFIG_THERMAL_STATISTICS
 void thermal_cooling_device_stats_update(struct thermal_cooling_device *cdev,
+					 struct thermal_instance *instance,
 					 unsigned long new_state);
 #else
 static inline void
 thermal_cooling_device_stats_update(struct thermal_cooling_device *cdev,
+				    struct thermal_instance *instance,
 				    unsigned long new_state) {}
 #endif /* CONFIG_THERMAL_STATISTICS */
 
diff --git a/drivers/thermal/thermal_helpers.c b/drivers/thermal/thermal_helpers.c
index cfba0965a22d..ec8e86394977 100644
--- a/drivers/thermal/thermal_helpers.c
+++ b/drivers/thermal/thermal_helpers.c
@@ -149,18 +149,19 @@ int thermal_zone_get_temp(struct thermal_zone_device *tz, int *temp)
 EXPORT_SYMBOL_GPL(thermal_zone_get_temp);
 
 static void thermal_cdev_set_cur_state(struct thermal_cooling_device *cdev,
+				       struct thermal_instance *target_instance,
 				       int target)
 {
 	if (cdev->ops->set_cur_state(cdev, target))
 		return;
 
 	thermal_notify_cdev_state_update(cdev->id, target);
-	thermal_cooling_device_stats_update(cdev, target);
+	thermal_cooling_device_stats_update(cdev, target_instance, target);
 }
 
 void __thermal_cdev_update(struct thermal_cooling_device *cdev)
 {
-	struct thermal_instance *instance;
+	struct thermal_instance *instance, *target_instance = NULL;
 	unsigned long target = 0;
 
 	/* Make sure cdev enters the deepest cooling state */
@@ -169,11 +170,13 @@ void __thermal_cdev_update(struct thermal_cooling_device *cdev)
 			instance->tz->id, instance->target);
 		if (instance->target == THERMAL_NO_TARGET)
 			continue;
-		if (instance->target > target)
+		if (instance->target > target) {
 			target = instance->target;
+			target_instance = instance;
+		}
 	}
 
-	thermal_cdev_set_cur_state(cdev, target);
+	thermal_cdev_set_cur_state(cdev, target_instance, target);
 
 	trace_cdev_update(cdev, target);
 	dev_dbg(&cdev->device, "set to state %lu\n", target);
diff --git a/drivers/thermal/thermal_sysfs.c b/drivers/thermal/thermal_sysfs.c
index 6c20c9f90a05..a3b71f03db75 100644
--- a/drivers/thermal/thermal_sysfs.c
+++ b/drivers/thermal/thermal_sysfs.c
@@ -632,7 +632,7 @@ cur_state_store(struct device *dev, struct device_attribute *attr,
 
 	result = cdev->ops->set_cur_state(cdev, state);
 	if (!result)
-		thermal_cooling_device_stats_update(cdev, state);
+		thermal_cooling_device_stats_update(cdev, NULL, state);
 
 	mutex_unlock(&cdev->lock);
 	return result ? result : count;
@@ -661,6 +661,7 @@ static const struct attribute_group *cooling_device_attr_groups[] = {
 };
 
 #ifdef CONFIG_THERMAL_STATISTICS
+/* thermal cooling device statistics handling */
 struct cooling_dev_stats {
 	spinlock_t lock;
 	unsigned int total_trans;
@@ -668,9 +669,29 @@ struct cooling_dev_stats {
 	ktime_t last_time;
 	ktime_t *time_in_state;
 	unsigned int *trans_table;
+	struct thermal_instance *last_instance;
+	struct thermal_instance *curr_instance;
 };
 
-static void update_time_in_state(struct cooling_dev_stats *stats)
+static void update_time_in_instance(struct cooling_dev_stats *stats,
+				    struct thermal_instance *instance,
+				    ktime_t now, ktime_t delta)
+{
+	if (!instance)
+		return;
+
+	stats->last_instance = stats->curr_instance;
+	stats->curr_instance = instance;
+
+	if (!stats->last_instance)
+		stats->last_instance = instance;
+
+	stats->last_instance->time_in =
+			ktime_add(stats->last_instance->time_in, delta);
+}
+
+static void update_time_in_state(struct cooling_dev_stats *stats,
+				 struct thermal_instance *instance)
 {
 	ktime_t now = ktime_get(), delta;
 
@@ -678,9 +699,12 @@ static void update_time_in_state(struct cooling_dev_stats *stats)
 	stats->time_in_state[stats->state] =
 		ktime_add(stats->time_in_state[stats->state], delta);
 	stats->last_time = now;
+
+	update_time_in_instance(stats, instance, now, delta);
 }
 
 void thermal_cooling_device_stats_update(struct thermal_cooling_device *cdev,
+					 struct thermal_instance *instance,
 					 unsigned long new_state)
 {
 	struct cooling_dev_stats *stats = cdev->stats;
@@ -695,7 +719,7 @@ void thermal_cooling_device_stats_update(struct thermal_cooling_device *cdev,
 	if (stats->state == new_state)
 		goto unlock;
 
-	update_time_in_state(stats);
+	update_time_in_state(stats, instance);
 	stats->trans_table[stats->state * (cdev->max_state + 1) + new_state]++;
 	stats->state = new_state;
 	stats->total_trans++;
@@ -744,7 +768,7 @@ time_in_state_ms_show(struct device *dev, struct device_attribute *attr,
 
 	spin_lock(&stats->lock);
 
-	update_time_in_state(stats);
+	update_time_in_state(stats, stats->curr_instance);
 
 	for (i = 0; i <= cdev->max_state; i++) {
 		len += sprintf(buf + len, "state%u\t%llu\n", i,
@@ -758,12 +782,98 @@ time_in_state_ms_show(struct device *dev, struct device_attribute *attr,
 	return len;
 }
 
+struct cdev_thermal_zone_residency {
+	char thermal_zone[THERMAL_NAME_LENGTH];
+	ktime_t time_in;
+	unsigned long counter;
+	struct list_head node; /* we build this as we go */
+};
+
+static void
+build_cdev_thermal_zone_residency(struct list_head *list,
+				  struct thermal_cooling_device *cdev)
+{
+	struct cdev_thermal_zone_residency *res, *update_res;
+	struct thermal_instance *instance;
+
+	/*
+	 * Build an array of pairs <thermal zone, time> to represent
+	 * how this cooling device was driven by each thermal zone
+	 */
+	list_for_each_entry(instance, &cdev->thermal_instances, cdev_node) {
+		update_res = NULL;
+
+		list_for_each_entry(res, list, node) {
+			if (strncmp(res->thermal_zone, instance->tz->type,
+				    THERMAL_NAME_LENGTH) == 0)
+				update_res = res;
+		}
+		if (!update_res) {
+			update_res = kzalloc(sizeof(*update_res), GFP_KERNEL);
+			strscpy(update_res->thermal_zone,
+				instance->tz->type, THERMAL_NAME_LENGTH);
+			list_add_tail(&update_res->node, list);
+		}
+	}
+}
+
+static ssize_t
+time_in_thermal_zone_ms_show(struct device *dev, struct device_attribute *attr,
+			     char *buf)
+{
+	LIST_HEAD(cdev_thermal_zone_list);
+	struct thermal_cooling_device *cdev = to_cooling_device(dev);
+	struct cooling_dev_stats *stats = cdev->stats;
+	struct cdev_thermal_zone_residency *res, *next;
+	struct thermal_instance *instance;
+	ssize_t len = 0, ret = 0;
+
+	mutex_lock(&cdev->lock);
+
+	spin_lock(&stats->lock);
+	update_time_in_state(stats, stats->curr_instance);
+	spin_unlock(&stats->lock);
+
+	build_cdev_thermal_zone_residency(&cdev_thermal_zone_list, cdev);
+
+	list_for_each_entry(instance, &cdev->thermal_instances, cdev_node)
+		list_for_each_entry(res, &cdev_thermal_zone_list, node)
+			if (strncmp(res->thermal_zone, instance->tz->type,
+				    THERMAL_NAME_LENGTH) == 0)
+				res->time_in = ktime_add(res->time_in,
+							 instance->time_in);
+
+	mutex_unlock(&cdev->lock);
+
+	list_for_each_entry_safe(res, next, &cdev_thermal_zone_list, node) {
+		ret = snprintf(buf + len, PAGE_SIZE - len,
+			       "thermal_zone: %s\t%llu\n",
+			       res->thermal_zone, ktime_to_ms(res->time_in));
+
+		if (ret == 0)
+			ret = -EOVERFLOW;
+
+		if (ret < 0)
+			break;
+
+		len += ret;
+	}
+
+	list_for_each_entry_safe(res, next, &cdev_thermal_zone_list, node) {
+		list_del(&res->node);
+		kfree(res);
+	}
+
+	return ret < 0 ? ret : len;
+}
+
 static ssize_t
 reset_store(struct device *dev, struct device_attribute *attr, const char *buf,
 	    size_t count)
 {
 	struct thermal_cooling_device *cdev = to_cooling_device(dev);
 	struct cooling_dev_stats *stats;
+	struct thermal_instance *instance;
 	int i, states;
 
 	mutex_lock(&cdev->lock);
@@ -774,6 +884,7 @@ reset_store(struct device *dev, struct device_attribute *attr, const char *buf,
 
 	states = cdev->max_state + 1;
 
+	mutex_lock(&cdev->lock);
 	spin_lock(&stats->lock);
 
 	stats->total_trans = 0;
@@ -784,7 +895,14 @@ reset_store(struct device *dev, struct device_attribute *attr, const char *buf,
 	for (i = 0; i < states; i++)
 		stats->time_in_state[i] = ktime_set(0, 0);
 
+	/* Make sure we reset all counters per instance */
+	list_for_each_entry(instance, &cdev->thermal_instances, cdev_node) {
+		instance->time_in = ktime_set(0, 0);
+	}
+
 	spin_unlock(&stats->lock);
+	mutex_unlock(&cdev->lock);
+
 
 unlock:
 	mutex_unlock(&cdev->lock);
@@ -852,12 +970,14 @@ static ssize_t trans_table_show(struct device *dev,
 
 static DEVICE_ATTR_RO(total_trans);
 static DEVICE_ATTR_RO(time_in_state_ms);
+static DEVICE_ATTR_RO(time_in_thermal_zone_ms);
 static DEVICE_ATTR_WO(reset);
 static DEVICE_ATTR_RO(trans_table);
 
 static struct attribute *cooling_device_stats_attrs[] = {
 	&dev_attr_total_trans.attr,
 	&dev_attr_time_in_state_ms.attr,
+	&dev_attr_time_in_thermal_zone_ms.attr,
 	&dev_attr_reset.attr,
 	&dev_attr_trans_table.attr,
 	NULL
-- 
2.34.1