Re: [PATCH RESEND 15/16] Thermal: Unify the code for both active and passive cooling

["Rafael J. Wysocki" <rjw@sisk.pl>]

On Wednesday, July 25, 2012, Zhang Rui wrote:
> Remove thermal_zone_device_passive(). And use
> thermal_zone_trip_update() and thermal_zone_do_update()
> for both active and passive cooling.
> 
> Signed-off-by: Zhang Rui <rui.zhang@intel.com>

Reviewed-by: Rafael J. Wysocki <rjw@sisk.pl>

> ---
>  drivers/thermal/thermal_sys.c |   97 ++++++++++-------------------------------
>  include/linux/thermal.h       |    2 +-
>  2 files changed, 24 insertions(+), 75 deletions(-)
> 
> diff --git a/drivers/thermal/thermal_sys.c b/drivers/thermal/thermal_sys.c
> index ee10df5..23a5c86 100644
> --- a/drivers/thermal/thermal_sys.c
> +++ b/drivers/thermal/thermal_sys.c
> @@ -730,73 +730,6 @@ static void thermal_zone_device_set_polling(struct thermal_zone_device *tz,
>  				      msecs_to_jiffies(delay));
>  }
>  
> -static void thermal_zone_device_passive(struct thermal_zone_device *tz,
> -					int temp, int trip_temp, int trip)
> -{
> -	enum thermal_trend trend;
> -	struct thermal_instance *instance;
> -	struct thermal_cooling_device *cdev;
> -	long state, max_state;
> -
> -	/*
> -	 * Above Trip?
> -	 * -----------
> -	 * Calculate the thermal trend (using the passive cooling equation)
> -	 * and modify the performance limit for all passive cooling devices
> -	 * accordingly.  Note that we assume symmetry.
> -	 */
> -	if (temp >= trip_temp) {
> -		tz->passive = true;
> -
> -		thermal_get_trend(tz, trip, &trend);
> -
> -		/* Heating up? */
> -		if (trend == THERMAL_TREND_RAISING) {
> -			list_for_each_entry(instance, &tz->thermal_instances,
> -					    tz_node) {
> -				if (instance->trip != trip)
> -					continue;
> -				cdev = instance->cdev;
> -				cdev->ops->get_cur_state(cdev, &state);
> -				cdev->ops->get_max_state(cdev, &max_state);
> -				if (state++ < max_state)
> -					cdev->ops->set_cur_state(cdev, state);
> -			}
> -		} else if (trend == THERMAL_TREND_DROPPING) { /* Cooling off? */
> -			list_for_each_entry(instance, &tz->thermal_instances,
> -					    tz_node) {
> -				if (instance->trip != trip)
> -					continue;
> -				cdev = instance->cdev;
> -				cdev->ops->get_cur_state(cdev, &state);
> -				cdev->ops->get_max_state(cdev, &max_state);
> -				if (state > 0)
> -					cdev->ops->set_cur_state(cdev, --state);
> -			}
> -		}
> -		return;
> -	}
> -
> -	/*
> -	 * Below Trip?
> -	 * -----------
> -	 * Implement passive cooling hysteresis to slowly increase performance
> -	 * and avoid thrashing around the passive trip point.  Note that we
> -	 * assume symmetry.
> -	 */
> -	list_for_each_entry(instance, &tz->thermal_instances, tz_node) {
> -		if (instance->trip != trip)
> -			continue;
> -		cdev = instance->cdev;
> -		cdev->ops->get_cur_state(cdev, &state);
> -		cdev->ops->get_max_state(cdev, &max_state);
> -		if (state > 0)
> -			cdev->ops->set_cur_state(cdev, --state);
> -		if (state == 0)
> -			tz->passive = false;
> -	}
> -}
> -
>  static void thermal_zone_device_check(struct work_struct *work)
>  {
>  	struct thermal_zone_device *tz = container_of(work, struct
> @@ -1118,7 +1051,7 @@ static void thermal_zone_do_update(struct thermal_zone_device *tz)
>  }
>  
>  /*
> - * Cooling algorithm for active trip points
> + * Cooling algorithm for both active and passive cooling
>   *
>   * 1. if the temperature is higher than a trip point,
>   *    a. if the trend is THERMAL_TREND_RAISING, use higher cooling
> @@ -1140,9 +1073,16 @@ static void thermal_zone_trip_update(struct thermal_zone_device *tz,
>  	struct thermal_cooling_device *cdev = NULL;
>  	unsigned long cur_state, max_state;
>  	long trip_temp;
> +	enum thermal_trip_type trip_type;
>  	enum thermal_trend trend;
>  
> -	tz->ops->get_trip_temp(tz, trip, &trip_temp);
> +	if (trip == THERMAL_TRIPS_NONE) {
> +		trip_temp = tz->forced_passive;
> +		trip_type = THERMAL_TRIPS_NONE;
> +	} else {
> +		tz->ops->get_trip_temp(tz, trip, &trip_temp);
> +		tz->ops->get_trip_type(tz, trip, &trip_type);
> +	}
>  
>  	if (temp >= trip_temp) {
>  		thermal_get_trend(tz, trip, &trend);
> @@ -1163,6 +1103,12 @@ static void thermal_zone_trip_update(struct thermal_zone_device *tz,
>  				cur_state = cur_state > instance->lower ?
>  				    (cur_state - 1) : instance->lower;
>  			}
> +
> +			/* activate a passive thermal instance */
> +			if (trip_type == THERMAL_TRIP_PASSIVE &&
> +			    instance->target == THERMAL_NO_TARGET)
> +				tz->passive++;
> +
>  			instance->target = cur_state;
>  			cdev->updated = false; /* cooling device needs update */
>  		}
> @@ -1179,6 +1125,11 @@ static void thermal_zone_trip_update(struct thermal_zone_device *tz,
>  
>  			cur_state = cur_state > instance->lower ?
>  				    (cur_state - 1) : THERMAL_NO_TARGET;
> +
> +			/* deactivate a passive thermal instance */
> +			if (trip_type == THERMAL_TRIP_PASSIVE &&
> +			    cur_state == THERMAL_NO_TARGET)
> +				tz->passive--;
>  			instance->target = cur_state;
>  			cdev->updated = false; /* cooling device needs update */
>  		}
> @@ -1235,16 +1186,14 @@ void thermal_zone_device_update(struct thermal_zone_device *tz)
>  			break;
>  		case THERMAL_TRIP_PASSIVE:
>  			if (temp >= trip_temp || tz->passive)
> -				thermal_zone_device_passive(tz, temp,
> -							    trip_temp, count);
> +				thermal_zone_trip_update(tz, count, temp);
>  			break;
>  		}
>  	}
>  
> -	thermal_zone_do_update(tz);
>  	if (tz->forced_passive)
> -		thermal_zone_device_passive(tz, temp, tz->forced_passive,
> -					    THERMAL_TRIPS_NONE);
> +		thermal_zone_trip_update(tz, THERMAL_TRIPS_NONE, temp);
> +	thermal_zone_do_update(tz);
>  
>  leave:
>  	if (tz->passive)
> diff --git a/include/linux/thermal.h b/include/linux/thermal.h
> index 3e66214..06fd04d 100644
> --- a/include/linux/thermal.h
> +++ b/include/linux/thermal.h
> @@ -121,7 +121,7 @@ struct thermal_zone_device {
>  	int polling_delay;
>  	int temperature;
>  	int last_temperature;
> -	bool passive;
> +	int passive;
>  	unsigned int forced_passive;
>  	const struct thermal_zone_device_ops *ops;
>  	struct list_head thermal_instances;
>