[PATCHv4 4/9] Thermal: Add APIs to bind cdev to new zone structure

[Durgadoss R]

This patch creates new APIs to add/remove a
cdev to/from a zone. This patch does not change
the old cooling device implementation.

Signed-off-by: Durgadoss R <durgadoss.r@xxxxxxxxx>
---
 drivers/thermal/thermal_core.c |  136 ++++++++++++++++++++++++++++++++++++++++
 include/linux/thermal.h        |    9 +++
 2 files changed, 145 insertions(+)

diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c
index a053b60..3c4ef62 100644
--- a/drivers/thermal/thermal_core.c
+++ b/drivers/thermal/thermal_core.c
@@ -58,6 +58,7 @@ static LIST_HEAD(thermal_governor_list);
 static DEFINE_MUTEX(thermal_list_lock);
 static DEFINE_MUTEX(sensor_list_lock);
 static DEFINE_MUTEX(zone_list_lock);
+static DEFINE_MUTEX(cdev_list_lock);
 static DEFINE_MUTEX(thermal_governor_lock);
 
 #define for_each_thermal_sensor(pos) \
@@ -86,6 +87,9 @@ static DEFINE_MUTEX(thermal_governor_lock);
 	ret;						\
 })
 
+#define for_each_cdev(pos) \
+	list_for_each_entry(pos, &thermal_cdev_list, node)
+
 static struct thermal_governor *__find_governor(const char *name)
 {
 	struct thermal_governor *pos;
@@ -511,6 +515,27 @@ static void remove_sensor_from_zone(struct thermal_zone *tz,
 	mutex_unlock(&tz->lock);
 }
 
+static void remove_cdev_from_zone(struct thermal_zone *tz,
+				struct thermal_cooling_device *cdev)
+{
+	int j, indx;
+
+	indx = GET_INDEX(tz, cdev, cdev);
+	if (indx < 0)
+		return;
+
+	sysfs_remove_link(&tz->device.kobj, kobject_name(&cdev->device.kobj));
+
+	mutex_lock(&tz->lock);
+
+	/* Shift the entries in the tz->cdevs array */
+	for (j = indx; j < MAX_CDEVS_PER_ZONE - 1; j++)
+		tz->cdevs[j] = tz->cdevs[j + 1];
+
+	tz->cdev_indx--;
+	mutex_unlock(&tz->lock);
+}
+
 /* sys I/F for thermal zone */
 
 #define to_thermal_zone(_dev) \
@@ -1555,6 +1580,7 @@ void thermal_cooling_device_unregister(struct thermal_cooling_device *cdev)
 	int i;
 	const struct thermal_zone_params *tzp;
 	struct thermal_zone_device *tz;
+	struct thermal_zone *tmp_tz;
 	struct thermal_cooling_device *pos = NULL;
 
 	if (!cdev)
@@ -1592,6 +1618,13 @@ void thermal_cooling_device_unregister(struct thermal_cooling_device *cdev)
 
 	mutex_unlock(&thermal_list_lock);
 
+	mutex_lock(&zone_list_lock);
+
+	for_each_thermal_zone(tmp_tz)
+		remove_cdev_from_zone(tmp_tz, cdev);
+
+	mutex_unlock(&zone_list_lock);
+
 	if (cdev->type[0])
 		device_remove_file(&cdev->device, &dev_attr_cdev_type);
 	device_remove_file(&cdev->device, &dev_attr_max_state);
@@ -1873,6 +1906,7 @@ void remove_thermal_zone(struct thermal_zone *tz)
 {
 	struct thermal_zone *pos, *next;
 	struct thermal_sensor *ts;
+	struct thermal_cooling_device *cdev;
 	bool found = false;
 
 	if (!tz)
@@ -1894,6 +1928,9 @@ void remove_thermal_zone(struct thermal_zone *tz)
 	for_each_thermal_sensor(ts)
 		remove_sensor_from_zone(tz, ts);
 
+	for_each_cdev(cdev)
+		remove_cdev_from_zone(tz, cdev);
+
 	device_remove_file(&tz->device, &dev_attr_zone_name);
 
 	mutex_destroy(&tz->lock);
@@ -1909,6 +1946,47 @@ exit:
 EXPORT_SYMBOL(remove_thermal_zone);
 
 /**
+ * get_cdev_by_name() - search for a cdev and returns its reference
+ * @name: cooling device name to fetch the reference
+ *
+ * On success returns a reference to an unique cdev with
+ * the name matching that of @name, an ERR_PTR otherwise:
+ * -EINVAL for invalid paramenters
+ * -ENODEV for cdev not found
+ * -EEXIST for multiple matches
+ */
+struct thermal_cooling_device *get_cdev_by_name(const char *name)
+{
+	int found = 0;
+	struct thermal_cooling_device *pos;
+	struct thermal_cooling_device *cdev = ERR_PTR(-EINVAL);
+
+	if (!name)
+		return cdev;
+
+	mutex_lock(&cdev_list_lock);
+	for_each_cdev(pos) {
+		if (!strnicmp(pos->type, name, THERMAL_NAME_LENGTH)) {
+			found++;
+			cdev = pos;
+		}
+	}
+	mutex_unlock(&cdev_list_lock);
+
+	/*
+	 * Nothing has been found; return an error code for it.
+	 * Return success only when an unique cdev is found.
+	 */
+	if (found == 0)
+		cdev = ERR_PTR(-ENODEV);
+	else if (found > 1)
+		cdev = ERR_PTR(-EEXIST);
+
+	return cdev;
+}
+EXPORT_SYMBOL(get_cdev_by_name);
+
+/**
  * get_sensor_by_name() - search for a sensor and returns its reference
  * @name: thermal sensor name to fetch the reference
  *
@@ -2003,6 +2081,64 @@ exit_zone:
 EXPORT_SYMBOL(add_sensor_to_zone);
 
 /**
+ * add_cdev_to_zone - Add @cdev to thermal zone @tz
+ * @tz:		Thermal zone reference
+ * @cdev:	Cooling device reference
+ *
+ * Returns 0 on success, otherwise
+ * -EINVAL for invalid paramenters
+ * -EINVAL when trying to add more cdevs than MAX_CDEVS_PER_ZONE
+ * -EEXIST when trying add existing cdev again
+ */
+int add_cdev_to_zone(struct thermal_zone *tz,
+			struct thermal_cooling_device *cdev)
+{
+	int ret;
+
+	if (!tz || !cdev)
+		return -EINVAL;
+
+	mutex_lock(&zone_list_lock);
+
+	/* Ensure we are not adding the same cdev again!! */
+	ret = GET_INDEX(tz, cdev, cdev);
+	if (ret >= 0) {
+		ret = -EEXIST;
+		goto exit_zone;
+	}
+
+	/* Protect against 'cdev' being unregistered */
+	mutex_lock(&cdev_list_lock);
+
+	ret = sysfs_create_link(&tz->device.kobj, &cdev->device.kobj,
+				kobject_name(&cdev->device.kobj));
+	if (ret)
+		goto exit_cdev;
+
+	mutex_lock(&tz->lock);
+
+	if (tz->cdev_indx >= MAX_CDEVS_PER_ZONE - 1) {
+		dev_err(&tz->device, "Only %d cdevs allowed per zone\n",
+					MAX_CDEVS_PER_ZONE);
+		sysfs_remove_link(&tz->device.kobj,
+				kobject_name(&cdev->device.kobj));
+		ret = -EINVAL;
+		goto exit_indx_check;
+	}
+
+	tz->cdevs[tz->cdev_indx++] = cdev;
+
+exit_indx_check:
+	mutex_unlock(&tz->lock);
+exit_cdev:
+	mutex_unlock(&cdev_list_lock);
+exit_zone:
+	mutex_unlock(&zone_list_lock);
+	return ret;
+}
+EXPORT_SYMBOL(add_cdev_to_zone);
+
+/**
  * thermal_sensor_register - register a new thermal sensor
  * @name:	name of the thermal sensor
  * @count:	Number of thresholds supported by hardware
diff --git a/include/linux/thermal.h b/include/linux/thermal.h
index 2e12321..da7520c 100644
--- a/include/linux/thermal.h
+++ b/include/linux/thermal.h
@@ -60,6 +60,8 @@
 
 #define MAX_SENSORS_PER_ZONE		5
 
+#define MAX_CDEVS_PER_ZONE		5
+
 struct thermal_sensor;
 struct thermal_zone_device;
 struct thermal_cooling_device;
@@ -223,6 +225,10 @@ struct thermal_zone {
 	/* Sensor level information */
 	int sensor_indx; /* index into 'sensors' array */
 	struct thermal_sensor *sensors[MAX_SENSORS_PER_ZONE];
+
+	/* cdev level information */
+	int cdev_indx; /* index into 'cdevs' array */
+	struct thermal_cooling_device *cdevs[MAX_CDEVS_PER_ZONE];
 };
 
 /* Structure that holds thermal governor information */
@@ -300,6 +306,9 @@ void remove_thermal_zone(struct thermal_zone *);
 int add_sensor_to_zone(struct thermal_zone *, struct thermal_sensor *);
 struct thermal_sensor *get_sensor_by_name(const char *);
 
+int add_cdev_to_zone(struct thermal_zone *, struct thermal_cooling_device *);
+struct thermal_cooling_device *get_cdev_by_name(const char *);
+
 #ifdef CONFIG_NET
 extern int thermal_generate_netlink_event(struct thermal_zone_device *tz,
 						enum events event);
-- 
1.7.9.5

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