Date:	Tue, 15 Oct 2013 18:22:41 +0800
From:	Zhang Rui <rui.zhang@...el.com>
To:	Durgadoss R <durgadoss.r@...el.com>
Cc:	eduardo.valentin@...com, linux-pm@...r.kernel.org,
	linux-kernel@...r.kernel.org, hongbo.zhang@...escale.com,
	wni@...dia.com
Subject: Re: [PATCHv4 3/9] Thermal: Create zone level APIs

On Wed, 2013-10-02 at 00:08 +0530, Durgadoss R wrote:
> This patch adds a new thermal_zone structure to
> thermal.h. Also, adds zone level APIs to the thermal
> framework.
> 
> A thermal zone is a hot spot on the platform, which
> can have one or more sensors and cooling devices attached
> to it. These sensors can be mapped to a set of cooling
> devices, which when throttled, can help to bring down
> the temperature of the hot spot.
> 
> Signed-off-by: Durgadoss R <durgadoss.r@...el.com>
> ---
>  drivers/thermal/thermal_core.c |  267 +++++++++++++++++++++++++++++++++++++++-
>  include/linux/thermal.h        |   23 ++++
>  2 files changed, 289 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c
> index 8c46567..a053b60 100644
> --- a/drivers/thermal/thermal_core.c
> +++ b/drivers/thermal/thermal_core.c
> @@ -44,19 +44,48 @@ MODULE_DESCRIPTION("Generic thermal management sysfs support");
>  MODULE_LICENSE("GPL v2");
>  
>  static DEFINE_IDR(thermal_tz_idr);
> +static DEFINE_IDR(thermal_zone_idr);
>  static DEFINE_IDR(thermal_cdev_idr);
>  static DEFINE_IDR(thermal_sensor_idr);
>  static DEFINE_MUTEX(thermal_idr_lock);
>  
>  static LIST_HEAD(thermal_tz_list);
>  static LIST_HEAD(thermal_sensor_list);
> +static LIST_HEAD(thermal_zone_list);
>  static LIST_HEAD(thermal_cdev_list);
>  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(thermal_governor_lock);
>  
> +#define for_each_thermal_sensor(pos) \
> +	list_for_each_entry(pos, &thermal_sensor_list, node)
> +
> +#define for_each_thermal_zone(pos) \
> +	list_for_each_entry(pos, &thermal_zone_list, node)
> +
> +#define GET_INDEX(tz, ptr, type)			\
> +({							\
> +	int i, ret = -EINVAL;				\
> +	do {						\
> +		if (!tz || !ptr)			\
> +			break;				\
> +		mutex_lock(&tz->lock);			\
> +		mutex_lock(&type##_list_lock);		\
> +		for (i = 0; i < tz->type##_indx; i++) {	\
> +			if (tz->type##s[i] == ptr) {	\
> +				ret = i;		\
> +				break;			\
> +			}				\
> +		}					\
> +		mutex_unlock(&type##_list_lock);	\
> +		mutex_unlock(&tz->lock);		\
> +	} while (0);					\
> +	ret;						\
> +})
> +
>  static struct thermal_governor *__find_governor(const char *name)
>  {
>  	struct thermal_governor *pos;
> @@ -461,15 +490,47 @@ static void thermal_zone_device_check(struct work_struct *work)
>  	thermal_zone_device_update(tz);
>  }
>  
> +static void remove_sensor_from_zone(struct thermal_zone *tz,
> +				struct thermal_sensor *ts)
> +{
> +	int j, indx;
> +
> +	indx = GET_INDEX(tz, ts, sensor);
> +	if (indx < 0)
> +		return;
> +
> +	sysfs_remove_link(&tz->device.kobj, kobject_name(&ts->device.kobj));
> +
> +	mutex_lock(&tz->lock);
> +
> +	/* Shift the entries in the tz->sensors array */
> +	for (j = indx; j < MAX_SENSORS_PER_ZONE - 1; j++)
> +		tz->sensors[j] = tz->sensors[j + 1];
> +
> +	tz->sensor_indx--;
> +	mutex_unlock(&tz->lock);
> +}
> +
>  /* sys I/F for thermal zone */
>  
>  #define to_thermal_zone(_dev) \
>  	container_of(_dev, struct thermal_zone_device, device)
>  
> +#define to_zone(_dev) \
> +	container_of(_dev, struct thermal_zone, device)
> +
>  #define to_thermal_sensor(_dev) \
>  	container_of(_dev, struct thermal_sensor, device)
>  
>  static ssize_t
> +zone_name_show(struct device *dev, struct device_attribute *attr, char *buf)
> +{
> +	struct thermal_zone *tz = to_zone(dev);
> +
> +	return sprintf(buf, "%s\n", tz->name);
> +}
> +
> +static ssize_t
>  sensor_name_show(struct device *dev, struct device_attribute *attr, char *buf)
>  {
>  	struct thermal_sensor *ts = to_thermal_sensor(dev);
> @@ -876,6 +937,8 @@ static DEVICE_ATTR(policy, S_IRUGO | S_IWUSR, policy_show, policy_store);
>  static DEVICE_ATTR(sensor_name, 0444, sensor_name_show, NULL);
>  static DEVICE_ATTR(temp_input, 0444, sensor_temp_show, NULL);
>  
> +static DEVICE_ATTR(zone_name, 0444, zone_name_show, NULL);
> +
>  /* sys I/F for cooling device */
>  #define to_cooling_device(_dev)	\
>  	container_of(_dev, struct thermal_cooling_device, device)
> @@ -1689,7 +1752,7 @@ static void remove_trip_attrs(struct thermal_zone_device *tz)
>  	kfree(tz->trip_hyst_attrs);
>  }
>  
> - /**
> +/**
>   * enable_sensor_thresholds - create sysfs nodes for thresholdX
>   * @ts:		the thermal sensor
>   * @count:	Number of thresholds supported by sensor hardware
> @@ -1746,6 +1809,200 @@ static int enable_sensor_thresholds(struct thermal_sensor *ts, int count)
>  }
>  
>  /**
> + * create_thermal_zone - create sysfs nodes for thermal zone
> + * @name:	Name of the thermla zone
> + * @devdata:	Data supplied by the caller
> + *
> + * On Success returns a thermal zone reference, otherwise:
> + * -EINVAL for invalid parameters,
> + * -ENOMEM for insufficient memory cases,
> + */
> +struct thermal_zone *create_thermal_zone(const char *name, void *devdata)
> +{
> +	struct thermal_zone *tz;
> +	int ret;
> +
> +	if (!name || (name && strlen(name) >= THERMAL_NAME_LENGTH))
> +		return ERR_PTR(-EINVAL);
> +
> +	tz = kzalloc(sizeof(*tz), GFP_KERNEL);
> +	if (!tz)
> +		return ERR_PTR(-ENOMEM);
> +
> +	idr_init(&tz->idr);
> +	ret = get_idr(&thermal_zone_idr, &thermal_idr_lock, &tz->id);
> +	if (ret)
> +		goto exit_free;
> +
> +	mutex_init(&tz->lock);
> +	strlcpy(tz->name, name, sizeof(tz->name));
> +	tz->devdata = devdata;
> +	tz->device.class = &thermal_class;
> +
> +	dev_set_name(&tz->device, "zone%d", tz->id);
> +	ret = device_register(&tz->device);
> +	if (ret)
> +		goto exit_idr;
> +
> +	ret = device_create_file(&tz->device, &dev_attr_zone_name);
> +	if (ret)
> +		goto exit_unregister;
> +
> +	/* Add this zone to the global list of thermal zones */
> +	mutex_lock(&zone_list_lock);
> +	list_add_tail(&tz->node, &thermal_zone_list);
> +	mutex_unlock(&zone_list_lock);
> +	return tz;
> +
> +exit_unregister:
> +	device_unregister(&tz->device);
> +exit_idr:
> +	mutex_destroy(&tz->lock);
> +	release_idr(&thermal_zone_idr, &thermal_idr_lock, tz->id);
> +exit_free:
> +	kfree(tz);
> +	return ERR_PTR(ret);
> +}
> +EXPORT_SYMBOL(create_thermal_zone);
> +
as this is a thermal subsystem API, I'd prefer to use the names starting
with thermal_xxx.

> +/**
> + * remove_thermal_zone - removes the sysfs nodes for given tz
> + * @tz:	Thermal zone to be removed.
> + */
> +void remove_thermal_zone(struct thermal_zone *tz)
> +{
> +	struct thermal_zone *pos, *next;
> +	struct thermal_sensor *ts;
> +	bool found = false;
> +
> +	if (!tz)
> +		return;
> +
> +	mutex_lock(&zone_list_lock);
> +
> +	list_for_each_entry_safe(pos, next, &thermal_zone_list, node) {
> +		if (pos == tz) {
> +			list_del(&tz->node);
> +			found = true;
> +			break;
> +		}
> +	}
> +
> +	if (!found)
> +		goto exit;
> +
> +	for_each_thermal_sensor(ts)
> +		remove_sensor_from_zone(tz, ts);
> +
> +	device_remove_file(&tz->device, &dev_attr_zone_name);
> +
> +	mutex_destroy(&tz->lock);
> +	release_idr(&thermal_zone_idr, &thermal_idr_lock, tz->id);
> +	idr_destroy(&tz->idr);
> +
> +	device_unregister(&tz->device);
> +	kfree(tz);
> +exit:
> +	mutex_unlock(&zone_list_lock);
> +	return;
> +}
> +EXPORT_SYMBOL(remove_thermal_zone);
> +
ditto

> +/**
> + * get_sensor_by_name() - search for a sensor and returns its reference
> + * @name: thermal sensor name to fetch the reference
> + *
> + * On success returns a reference to a unique sensor with
> + * name matching that of @name, an ERR_PTR otherwise:
> + * -EINVAL for invalid paramenters
> + * -ENODEV for sensor not found
> + * -EEXIST for multiple matches
> + */
> +struct thermal_sensor *get_sensor_by_name(const char *name)
> +{
> +	int found = 0;
> +	struct thermal_sensor *pos;
> +	struct thermal_sensor *ts = ERR_PTR(-EINVAL);
> +
> +	if (!name)
> +		return ts;
> +
> +	mutex_lock(&sensor_list_lock);
> +	for_each_thermal_sensor(pos) {
> +		if (!strnicmp(pos->name, name, THERMAL_NAME_LENGTH)) {
> +			found++;
> +			ts = pos;
> +		}
> +	}
> +	mutex_unlock(&sensor_list_lock);
> +
> +	if (found == 0)
> +		ts = ERR_PTR(-ENODEV);
> +	else if (found > 1)
> +		ts = ERR_PTR(-EEXIST);
> +
> +	return ts;
> +}
> +EXPORT_SYMBOL(get_sensor_by_name);
> +
ditto

> +/**
> + * add_sensor_to_zone - Add @ts to thermal zone @tz
> + * @tz:		Thermal zone reference
> + * @ts:		Thermal sensor reference
> + *
> + * Returns 0 on success, otherwise
> + * -EINVAL for invalid paramenters
> + * -EINVAL when trying to add more zones than MAX_SENSORS_PER_ZONE
> + * -EEXIST when trying add existing thermal sensor again
> + */
> +int add_sensor_to_zone(struct thermal_zone *tz, struct thermal_sensor *ts)
> +{
> +	int ret;
> +
> +	if (!tz || !ts)
> +		return -EINVAL;
> +
> +	mutex_lock(&zone_list_lock);
> +
> +	/* Ensure we are not adding the same sensor again!! */
> +	ret = GET_INDEX(tz, ts, sensor);
> +	if (ret >= 0) {
> +		ret = -EEXIST;
> +		goto exit_zone;
> +	}
> +
> +	/* Protect against 'ts' being unregistered */
> +	mutex_lock(&sensor_list_lock);
> +
> +	ret = sysfs_create_link(&tz->device.kobj, &ts->device.kobj,
> +				kobject_name(&ts->device.kobj));
> +	if (ret)
> +		goto exit_sensor;
> +
> +	mutex_lock(&tz->lock);
> +
> +	if (tz->sensor_indx >= MAX_SENSORS_PER_ZONE - 1) {
> +		dev_err(&tz->device, "Only %d sensors allowed per zone\n",
> +					MAX_SENSORS_PER_ZONE);
> +		sysfs_remove_link(&tz->device.kobj,
> +					kobject_name(&ts->device.kobj));
> +		ret = -EINVAL;
> +		goto exit_indx_check;
> +	}
> +
> +	tz->sensors[tz->sensor_indx++] = ts;
> +
> +exit_indx_check:
> +	mutex_unlock(&tz->lock);
> +exit_sensor:
> +	mutex_unlock(&sensor_list_lock);
> +exit_zone:
> +	mutex_unlock(&zone_list_lock);
> +	return ret;
> +}
> +EXPORT_SYMBOL(add_sensor_to_zone);
> +
ditto

> +/**
>   * thermal_sensor_register - register a new thermal sensor
>   * @name:	name of the thermal sensor
>   * @count:	Number of thresholds supported by hardware
> @@ -1829,6 +2086,7 @@ EXPORT_SYMBOL(thermal_sensor_register);
>  void thermal_sensor_unregister(struct thermal_sensor *ts)
>  {
>  	int i;
> +	struct thermal_zone *tz;
>  	struct thermal_sensor *pos, *next;
>  	bool found = false;
>  
> @@ -1848,6 +2106,13 @@ void thermal_sensor_unregister(struct thermal_sensor *ts)
>  	if (!found)
>  		return;
>  
> +	mutex_lock(&zone_list_lock);
> +
> +	for_each_thermal_zone(tz)
> +		remove_sensor_from_zone(tz, ts);
> +
> +	mutex_unlock(&zone_list_lock);
> +
I do not see the code to bind the sensors to zone in this patch, and I
guess we support manually binding only, via explicitly calling () in
platform thermal driver, at the moment, right?

thanks,
rui
>  	for (i = 0; i < ts->thresholds; i++) {
>  		device_remove_file(&ts->device, &ts->thresh_attrs[i].attr);
>  		if (ts->ops->get_hyst) {
> diff --git a/include/linux/thermal.h b/include/linux/thermal.h
> index 25fc562..2e12321 100644
> --- a/include/linux/thermal.h
> +++ b/include/linux/thermal.h
> @@ -58,6 +58,8 @@
>  #define DEFAULT_THERMAL_GOVERNOR       "user_space"
>  #endif
>  
> +#define MAX_SENSORS_PER_ZONE		5
> +
>  struct thermal_sensor;
>  struct thermal_zone_device;
>  struct thermal_cooling_device;
> @@ -207,6 +209,22 @@ struct thermal_zone_device {
>  	struct delayed_work poll_queue;
>  };
>  
> +struct thermal_zone {
> +	char name[THERMAL_NAME_LENGTH];
> +	int id;
> +	void *devdata;
> +	struct thermal_zone *ops;
> +	struct thermal_governor *governor;
> +	struct idr idr;
> +	struct mutex lock; /* protect elements of this structure */
> +	struct device device;
> +	struct list_head node;
> +
> +	/* Sensor level information */
> +	int sensor_indx; /* index into 'sensors' array */
> +	struct thermal_sensor *sensors[MAX_SENSORS_PER_ZONE];
> +};
> +
>  /* Structure that holds thermal governor information */
>  struct thermal_governor {
>  	char name[THERMAL_NAME_LENGTH];
> @@ -277,6 +295,11 @@ struct thermal_sensor *thermal_sensor_register(const char *, int,
>  				struct thermal_sensor_ops *, void *);
>  void thermal_sensor_unregister(struct thermal_sensor *);
>  
> +struct thermal_zone *create_thermal_zone(const char *, void *);
> +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 *);
> +
>  #ifdef CONFIG_NET
>  extern int thermal_generate_netlink_event(struct thermal_zone_device *tz,
>  						enum events event);


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