@@ -6,6 +6,7 @@ CFLAGS_thermal_core.o := -I$(src)
obj-$(CONFIG_THERMAL) += thermal_sys.o
thermal_sys-y += thermal_core.o thermal_sysfs.o
thermal_sys-y += thermal_trip.o thermal_helpers.o
+thermal_sys-y += thermal_thresholds.o
# netlink interface to manage the thermal framework
thermal_sys-$(CONFIG_THERMAL_NETLINK) += thermal_netlink.o
@@ -13,6 +13,7 @@
#include <linux/thermal.h>
#include "thermal_netlink.h"
+#include "thermal_thresholds.h"
#include "thermal_debugfs.h"
struct thermal_attr {
@@ -139,6 +140,7 @@ struct thermal_zone_device {
#ifdef CONFIG_THERMAL_DEBUGFS
struct thermal_debugfs *debugfs;
#endif
+ struct list_head user_thresholds;
struct thermal_trip_desc trips[] __counted_by(num_trips);
};
new file mode 100644
@@ -0,0 +1,229 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 2024 Linaro Limited
+ *
+ * Author: Daniel Lezcano <daniel.lezcano@linaro.org>
+ *
+ * Thermal thresholds
+ */
+#include <linux/list.h>
+#include <linux/list_sort.h>
+#include <linux/slab.h>
+
+#include "thermal_core.h"
+#include "thermal_thresholds.h"
+
+int thermal_thresholds_init(struct thermal_zone_device *tz)
+{
+ INIT_LIST_HEAD(&tz->user_thresholds);
+
+ return 0;
+}
+
+void thermal_thresholds_flush(struct thermal_zone_device *tz)
+{
+ struct list_head *thresholds = &tz->user_thresholds;
+ struct user_threshold *entry, *tmp;
+
+ lockdep_assert_held(&tz->lock);
+
+ list_for_each_entry_safe(entry, tmp, thresholds, list_node) {
+ list_del(&entry->list_node);
+ kfree(entry);
+ }
+
+ __thermal_zone_device_update(tz, THERMAL_TZ_FLUSH_THRESHOLDS);
+}
+
+void thermal_thresholds_exit(struct thermal_zone_device *tz)
+{
+ thermal_thresholds_flush(tz);
+}
+
+static int __thermal_thresholds_cmp(void *data,
+ const struct list_head *l1,
+ const struct list_head *l2)
+{
+ struct user_threshold *t1 = container_of(l1, struct user_threshold, list_node);
+ struct user_threshold *t2 = container_of(l2, struct user_threshold, list_node);
+
+ return t1->temperature - t2->temperature;
+}
+
+static struct user_threshold *__thermal_thresholds_find(const struct list_head *thresholds,
+ int temperature)
+{
+ struct user_threshold *t;
+
+ list_for_each_entry(t, thresholds, list_node)
+ if (t->temperature == temperature)
+ return t;
+
+ return NULL;
+}
+
+static bool __thermal_threshold_is_crossed(struct user_threshold *threshold, int temperature,
+ int last_temperature, int direction,
+ int *low, int *high)
+{
+
+ if (temperature >= threshold->temperature) {
+ if (threshold->temperature > *low &&
+ THERMAL_THRESHOLD_WAY_DOWN & threshold->direction)
+ *low = threshold->temperature;
+
+ if (last_temperature < threshold->temperature &&
+ threshold->direction & direction)
+ return true;
+ } else {
+ if (threshold->temperature < *high && THERMAL_THRESHOLD_WAY_UP
+ & threshold->direction)
+ *high = threshold->temperature;
+
+ if (last_temperature >= threshold->temperature &&
+ threshold->direction & direction)
+ return true;
+ }
+
+ return false;
+}
+
+static bool thermal_thresholds_handle_raising(struct list_head *thresholds, int temperature,
+ int last_temperature, int *low, int *high)
+{
+ struct user_threshold *t;
+
+ list_for_each_entry(t, thresholds, list_node) {
+ if (__thermal_threshold_is_crossed(t, temperature, last_temperature,
+ THERMAL_THRESHOLD_WAY_UP, low, high))
+ return true;
+ }
+
+ return false;
+}
+
+static bool thermal_thresholds_handle_dropping(struct list_head *thresholds, int temperature,
+ int last_temperature, int *low, int *high)
+{
+ struct user_threshold *t;
+
+ list_for_each_entry_reverse(t, thresholds, list_node) {
+ if (__thermal_threshold_is_crossed(t, temperature, last_temperature,
+ THERMAL_THRESHOLD_WAY_DOWN, low, high))
+ return true;
+ }
+
+ return false;
+}
+
+void thermal_thresholds_handle(struct thermal_zone_device *tz, int *low, int *high)
+{
+ struct list_head *thresholds = &tz->user_thresholds;
+
+ int temperature = tz->temperature;
+ int last_temperature = tz->last_temperature;
+ bool notify;
+
+ lockdep_assert_held(&tz->lock);
+
+ /*
+ * We need a second update in order to detect a threshold being crossed
+ */
+ if (last_temperature == THERMAL_TEMP_INVALID)
+ return;
+
+ /*
+ * The temperature is stable, so obviously we can not have
+ * crossed a threshold.
+ */
+ if (last_temperature == temperature)
+ return;
+
+ /*
+ * Since last update the temperature:
+ * - increased : thresholds are crossed the way up
+ * - decreased : thresholds are crossed the way down
+ */
+ if (temperature > last_temperature)
+ notify = thermal_thresholds_handle_raising(thresholds, temperature,
+ last_temperature, low, high);
+ else
+ notify = thermal_thresholds_handle_dropping(thresholds, temperature,
+ last_temperature, low, high);
+
+ if (notify)
+ pr_debug("A threshold has been crossed the way %s, with a temperature=%d, last_temperature=%d\n",
+ temperature > last_temperature ? "up" : "down", temperature, last_temperature);
+}
+
+int thermal_thresholds_add(struct thermal_zone_device *tz, int temperature, int direction)
+{
+ struct list_head *thresholds = &tz->user_thresholds;
+ struct user_threshold *t;
+
+ lockdep_assert_held(&tz->lock);
+
+ t = __thermal_thresholds_find(thresholds, temperature);
+ if (t) {
+ if (t->direction == direction)
+ return -EEXIST;
+
+ t->direction |= direction;
+ } else {
+
+ t = kmalloc(sizeof(*t), GFP_KERNEL);
+ if (!t)
+ return -ENOMEM;
+
+ INIT_LIST_HEAD(&t->list_node);
+ t->temperature = temperature;
+ t->direction = direction;
+ list_add(&t->list_node, thresholds);
+ list_sort(NULL, thresholds, __thermal_thresholds_cmp);
+ }
+
+ __thermal_zone_device_update(tz, THERMAL_TZ_ADD_THRESHOLD);
+
+ return 0;
+}
+
+int thermal_thresholds_delete(struct thermal_zone_device *tz, int temperature, int direction)
+{
+ struct list_head *thresholds = &tz->user_thresholds;
+ struct user_threshold *t;
+
+ lockdep_assert_held(&tz->lock);
+
+ t = __thermal_thresholds_find(thresholds, temperature);
+ if (!t)
+ return -ENOENT;
+
+ if (t->direction == direction) {
+ list_del(&t->list_node);
+ kfree(t);
+ } else {
+ t->direction &= ~direction;
+ }
+
+ __thermal_zone_device_update(tz, THERMAL_TZ_DEL_THRESHOLD);
+
+ return 0;
+}
+
+int thermal_thresholds_for_each(struct thermal_zone_device *tz,
+ int (*cb)(struct user_threshold *, void *arg), void *arg)
+{
+ struct list_head *thresholds = &tz->user_thresholds;
+ struct user_threshold *entry;
+ int ret;
+
+ lockdep_assert_held(&tz->lock);
+
+ list_for_each_entry(entry, thresholds, list_node) {
+ ret = cb(entry, arg);
+ if (ret)
+ return ret;
+ }
+
+ return 0;
+}
new file mode 100644
@@ -0,0 +1,19 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __THERMAL_THRESHOLDS_H__
+#define __THERMAL_THRESHOLDS_H__
+
+struct user_threshold {
+ struct list_head list_node;
+ int temperature;
+ int direction;
+};
+
+int thermal_thresholds_init(struct thermal_zone_device *tz);
+void thermal_thresholds_exit(struct thermal_zone_device *tz);
+void thermal_thresholds_flush(struct thermal_zone_device *tz);
+void thermal_thresholds_handle(struct thermal_zone_device *tz, int *low, int *high);
+int thermal_thresholds_add(struct thermal_zone_device *tz, int temperature, int direction);
+int thermal_thresholds_delete(struct thermal_zone_device *tz, int temperature, int direction);
+int thermal_thresholds_for_each(struct thermal_zone_device *tz,
+ int (*cb)(struct user_threshold *, void *arg), void *arg);
+#endif
@@ -56,6 +56,9 @@ enum thermal_notify_event {
THERMAL_TZ_UNBIND_CDEV, /* Cooling dev is unbind from the thermal zone */
THERMAL_INSTANCE_WEIGHT_CHANGED, /* Thermal instance weight changed */
THERMAL_TZ_RESUME, /* Thermal zone is resuming after system sleep */
+ THERMAL_TZ_ADD_THRESHOLD, /* Threshold added */
+ THERMAL_TZ_DEL_THRESHOLD, /* Threshold deleted */
+ THERMAL_TZ_FLUSH_THRESHOLDS, /* All thresholds deleted */
};
/**
@@ -3,6 +3,8 @@
#define _UAPI_LINUX_THERMAL_H
#define THERMAL_NAME_LENGTH 20
+#define THERMAL_THRESHOLD_WAY_UP 0x1
+#define THERMAL_THRESHOLD_WAY_DOWN 0x2
enum thermal_device_mode {
THERMAL_DEVICE_DISABLED = 0,
The user thresholds mechanism is a way to have the userspace to tell the thermal framework to send a notification when a temperature limit is crossed. There is no id, no hysteresis, just the temperature and the direction of the limit crossing. That means we can be notified when a threshold is crossed the way up only, or the way down only or both ways. That allows to create hysteresis values if it is needed. A threshold can be added, deleted or flushed. The latter means all thresholds belonging to a thermal zone will be deleted. When a threshold is added: - if the same threshold (temperature and direction) exists, an error is returned - if a threshold is specified with the same temperature but a different direction, the specified direction is added - if there is no threshold with the same temperature then it is created When a threshold is deleted: - if the same threshold (temperature and direction) exists, it is deleted - if a threshold is specified with the same temperature but a different direction, the specified direction is removed - if there is no threshold with the same temperature, then an error is returned When the threshold are flushed: - All thresholds related to a thermal zone are deleted When a threshold is crossed: - the userspace does not need to know which threshold(s) have been crossed, it will be notified with the current temperature and the previous temperature - if multiple thresholds have been crossed between two updates only one notification will be send to the userspace, it is pointless to send a notification per thresholds crossed as the userspace can handle that easily when it has the temperature delta information Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org> --- drivers/thermal/Makefile | 1 + drivers/thermal/thermal_core.h | 2 + drivers/thermal/thermal_thresholds.c | 229 +++++++++++++++++++++++++++ drivers/thermal/thermal_thresholds.h | 19 +++ include/linux/thermal.h | 3 + include/uapi/linux/thermal.h | 2 + 6 files changed, 256 insertions(+) create mode 100644 drivers/thermal/thermal_thresholds.c create mode 100644 drivers/thermal/thermal_thresholds.h