diff mbox series

[1/2] thermal: devfreq_cooling: Use PM QoS to set frequency limits

Message ID 20200110094913.1.I146403d05b9ec82f48b807efd416a57f545b447a@changeid (mailing list archive)
State Changes Requested
Delegated to: Chanwoo Choi
Headers show
Series [1/2] thermal: devfreq_cooling: Use PM QoS to set frequency limits | expand

Commit Message

Matthias Kaehlcke Jan. 10, 2020, 5:49 p.m. UTC
Now that devfreq supports limiting the frequency range of a device
through PM QoS make use of it instead of disabling OPPs that should
not be used.

Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
---

 drivers/thermal/devfreq_cooling.c | 66 ++++++++++---------------------
 1 file changed, 20 insertions(+), 46 deletions(-)

Comments

Chanwoo Choi Jan. 13, 2020, 7:25 a.m. UTC | #1
Hi,

On 1/11/20 2:49 AM, Matthias Kaehlcke wrote:
> Now that devfreq supports limiting the frequency range of a device
> through PM QoS make use of it instead of disabling OPPs that should
> not be used.
> 
> Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
> ---
> 
>  drivers/thermal/devfreq_cooling.c | 66 ++++++++++---------------------
>  1 file changed, 20 insertions(+), 46 deletions(-)
> 
> diff --git a/drivers/thermal/devfreq_cooling.c b/drivers/thermal/devfreq_cooling.c
> index ef59256887ff..3a63603afcf2 100644
> --- a/drivers/thermal/devfreq_cooling.c
> +++ b/drivers/thermal/devfreq_cooling.c
> @@ -24,11 +24,13 @@
>  #include <linux/idr.h>
>  #include <linux/slab.h>
>  #include <linux/pm_opp.h>
> +#include <linux/pm_qos.h>
>  #include <linux/thermal.h>
>  
>  #include <trace/events/thermal.h>
>  
> -#define SCALE_ERROR_MITIGATION 100
> +#define HZ_PER_KHZ		1000
> +#define SCALE_ERROR_MITIGATION	100
>  
>  static DEFINE_IDA(devfreq_ida);
>  
> @@ -65,49 +67,9 @@ struct devfreq_cooling_device {
>  	struct devfreq_cooling_power *power_ops;
>  	u32 res_util;
>  	int capped_state;
> +	struct dev_pm_qos_request req_max_freq;

Need to add the description of 'req_max_freq'.

>  };
>  
> -/**
> - * partition_enable_opps() - disable all opps above a given state
> - * @dfc:	Pointer to devfreq we are operating on
> - * @cdev_state:	cooling device state we're setting
> - *
> - * Go through the OPPs of the device, enabling all OPPs until
> - * @cdev_state and disabling those frequencies above it.
> - */
> -static int partition_enable_opps(struct devfreq_cooling_device *dfc,
> -				 unsigned long cdev_state)
> -{
> -	int i;
> -	struct device *dev = dfc->devfreq->dev.parent;
> -
> -	for (i = 0; i < dfc->freq_table_size; i++) {
> -		struct dev_pm_opp *opp;
> -		int ret = 0;
> -		unsigned int freq = dfc->freq_table[i];
> -		bool want_enable = i >= cdev_state ? true : false;
> -
> -		opp = dev_pm_opp_find_freq_exact(dev, freq, !want_enable);
> -
> -		if (PTR_ERR(opp) == -ERANGE)
> -			continue;
> -		else if (IS_ERR(opp))
> -			return PTR_ERR(opp);
> -
> -		dev_pm_opp_put(opp);
> -
> -		if (want_enable)
> -			ret = dev_pm_opp_enable(dev, freq);
> -		else
> -			ret = dev_pm_opp_disable(dev, freq);
> -
> -		if (ret)
> -			return ret;
> -	}
> -
> -	return 0;
> -}
> -
>  static int devfreq_cooling_get_max_state(struct thermal_cooling_device *cdev,
>  					 unsigned long *state)
>  {
> @@ -134,7 +96,7 @@ static int devfreq_cooling_set_cur_state(struct thermal_cooling_device *cdev,
>  	struct devfreq_cooling_device *dfc = cdev->devdata;
>  	struct devfreq *df = dfc->devfreq;
>  	struct device *dev = df->dev.parent;
> -	int ret;
> +	unsigned long freq;
>  
>  	if (state == dfc->cooling_state)
>  		return 0;
> @@ -144,9 +106,10 @@ static int devfreq_cooling_set_cur_state(struct thermal_cooling_device *cdev,
>  	if (state >= dfc->freq_table_size)
>  		return -EINVAL;
>  
> -	ret = partition_enable_opps(dfc, state);
> -	if (ret)
> -		return ret;
> +	freq = dfc->freq_table[state];
> +
> +	dev_pm_qos_update_request(&dfc->req_max_freq,
> +				  DIV_ROUND_UP(freq, HZ_PER_KHZ));
>  
>  	dfc->cooling_state = state;
>  
> @@ -529,6 +492,12 @@ of_devfreq_cooling_register_power(struct device_node *np, struct devfreq *df,
>  	if (err)
>  		goto free_dfc;
>  
> +	err = dev_pm_qos_add_request(df->dev.parent, &dfc->req_max_freq,
> +				     DEV_PM_QOS_MAX_FREQUENCY,
> +				     PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE);
> +	if (err < 0)
> +		goto remove_qos_req;

Jump 'free_table' instead of 'remove_qos_req'.

> +
>  	err = ida_simple_get(&devfreq_ida, 0, 0, GFP_KERNEL);
>  	if (err < 0)
>  		goto free_tables;

Jump remove_qos_req.

> @@ -552,6 +521,10 @@ of_devfreq_cooling_register_power(struct device_node *np, struct devfreq *df,
>  
>  release_ida:
>  	ida_simple_remove(&devfreq_ida, dfc->id);
> +
> +remove_qos_req:
> +	dev_pm_qos_remove_request(&dfc->req_max_freq);
> +
>  free_tables:
>  	kfree(dfc->power_table);
>  	kfree(dfc->freq_table);
> @@ -600,6 +573,7 @@ void devfreq_cooling_unregister(struct thermal_cooling_device *cdev)
>  
>  	thermal_cooling_device_unregister(dfc->cdev);
>  	ida_simple_remove(&devfreq_ida, dfc->id);
> +	dev_pm_qos_remove_request(&dfc->req_max_freq);
>  	kfree(dfc->power_table);
>  	kfree(dfc->freq_table);
>  
>
Leonard Crestez Jan. 14, 2020, 4:08 p.m. UTC | #2
On 10.01.2020 19:49, Matthias Kaehlcke wrote:
> Now that devfreq supports limiting the frequency range of a device
> through PM QoS make use of it instead of disabling OPPs that should
> not be used.
> 
> Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
> ---

It is not obvious but this changes behavior when min max requests 
conflict (min > max): with PM QoS a MIN_FREQUENCY request takes 
precedence but if higher OPPs are disabled then this will override 
MIN_FREQUENCY.

There are very few users of this functionality so I don't think there 
are any systems that depend on this behaving one way or the other but 
perhaps it should be mentioned in commit message?

As far as I can tell the only user of devfreq_cooling in upstream is 
drivers/gpu/drm/panfrost?

>   drivers/thermal/devfreq_cooling.c | 66 ++++++++++---------------------
>   1 file changed, 20 insertions(+), 46 deletions(-)
> 
> diff --git a/drivers/thermal/devfreq_cooling.c b/drivers/thermal/devfreq_cooling.c
> index ef59256887ff..3a63603afcf2 100644
> --- a/drivers/thermal/devfreq_cooling.c
> +++ b/drivers/thermal/devfreq_cooling.c
> @@ -24,11 +24,13 @@
>   #include <linux/idr.h>
>   #include <linux/slab.h>
>   #include <linux/pm_opp.h>
> +#include <linux/pm_qos.h>
>   #include <linux/thermal.h>
>   
>   #include <trace/events/thermal.h>
>   
> -#define SCALE_ERROR_MITIGATION 100
> +#define HZ_PER_KHZ		1000
> +#define SCALE_ERROR_MITIGATION	100
>   
>   static DEFINE_IDA(devfreq_ida);
>   
> @@ -65,49 +67,9 @@ struct devfreq_cooling_device {
>   	struct devfreq_cooling_power *power_ops;
>   	u32 res_util;
>   	int capped_state;
> +	struct dev_pm_qos_request req_max_freq;
>   };
>   
> -/**
> - * partition_enable_opps() - disable all opps above a given state
> - * @dfc:	Pointer to devfreq we are operating on
> - * @cdev_state:	cooling device state we're setting
> - *
> - * Go through the OPPs of the device, enabling all OPPs until
> - * @cdev_state and disabling those frequencies above it.
> - */
> -static int partition_enable_opps(struct devfreq_cooling_device *dfc,
> -				 unsigned long cdev_state)
> -{
> -	int i;
> -	struct device *dev = dfc->devfreq->dev.parent;
> -
> -	for (i = 0; i < dfc->freq_table_size; i++) {
> -		struct dev_pm_opp *opp;
> -		int ret = 0;
> -		unsigned int freq = dfc->freq_table[i];
> -		bool want_enable = i >= cdev_state ? true : false;
> -
> -		opp = dev_pm_opp_find_freq_exact(dev, freq, !want_enable);
> -
> -		if (PTR_ERR(opp) == -ERANGE)
> -			continue;
> -		else if (IS_ERR(opp))
> -			return PTR_ERR(opp);
> -
> -		dev_pm_opp_put(opp);
> -
> -		if (want_enable)
> -			ret = dev_pm_opp_enable(dev, freq);
> -		else
> -			ret = dev_pm_opp_disable(dev, freq);
> -
> -		if (ret)
> -			return ret;
> -	}
> -
> -	return 0;
> -}
> -
>   static int devfreq_cooling_get_max_state(struct thermal_cooling_device *cdev,
>   					 unsigned long *state)
>   {
> @@ -134,7 +96,7 @@ static int devfreq_cooling_set_cur_state(struct thermal_cooling_device *cdev,
>   	struct devfreq_cooling_device *dfc = cdev->devdata;
>   	struct devfreq *df = dfc->devfreq;
>   	struct device *dev = df->dev.parent;
> -	int ret;
> +	unsigned long freq;
>   
>   	if (state == dfc->cooling_state)
>   		return 0;
> @@ -144,9 +106,10 @@ static int devfreq_cooling_set_cur_state(struct thermal_cooling_device *cdev,
>   	if (state >= dfc->freq_table_size)
>   		return -EINVAL;
>   
> -	ret = partition_enable_opps(dfc, state);
> -	if (ret)
> -		return ret;
> +	freq = dfc->freq_table[state];
> +
> +	dev_pm_qos_update_request(&dfc->req_max_freq,
> +				  DIV_ROUND_UP(freq, HZ_PER_KHZ));
>   
>   	dfc->cooling_state = state;
>   
> @@ -529,6 +492,12 @@ of_devfreq_cooling_register_power(struct device_node *np, struct devfreq *df,
>   	if (err)
>   		goto free_dfc;
>   
> +	err = dev_pm_qos_add_request(df->dev.parent, &dfc->req_max_freq,
> +				     DEV_PM_QOS_MAX_FREQUENCY,
> +				     PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE);
> +	if (err < 0)
> +		goto remove_qos_req;
> +
>   	err = ida_simple_get(&devfreq_ida, 0, 0, GFP_KERNEL);
>   	if (err < 0)
>   		goto free_tables;
> @@ -552,6 +521,10 @@ of_devfreq_cooling_register_power(struct device_node *np, struct devfreq *df,
>   
>   release_ida:
>   	ida_simple_remove(&devfreq_ida, dfc->id);
> +
> +remove_qos_req:
> +	dev_pm_qos_remove_request(&dfc->req_max_freq); > +

A quirk of the dev_pm_qos API is that dev_pm_qos_remove_request prints a 
WARN splat if !dev_pm_qos_request_active and this can true on 
dev_pm_qos_add_request error.

I dealt with this by checking dev_pm_qos_request_active explicitly but 
perhaps dev_pm_qos API could be changed? In general "free/release" 
functions shouldn't complain if there's nothing to do.

>   free_tables:
>   	kfree(dfc->power_table);
>   	kfree(dfc->freq_table);
> @@ -600,6 +573,7 @@ void devfreq_cooling_unregister(struct thermal_cooling_device *cdev)
>   
>   	thermal_cooling_device_unregister(dfc->cdev);
>   	ida_simple_remove(&devfreq_ida, dfc->id);
> +	dev_pm_qos_remove_request(&dfc->req_max_freq);
>   	kfree(dfc->power_table);
>   	kfree(dfc->freq_table);
Matthias Kaehlcke Jan. 14, 2020, 6:51 p.m. UTC | #3
On Mon, Jan 13, 2020 at 04:25:17PM +0900, Chanwoo Choi wrote:
> Hi,
> 
> On 1/11/20 2:49 AM, Matthias Kaehlcke wrote:
> > Now that devfreq supports limiting the frequency range of a device
> > through PM QoS make use of it instead of disabling OPPs that should
> > not be used.
> > 
> > Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
> > ---
> > 
> >  drivers/thermal/devfreq_cooling.c | 66 ++++++++++---------------------
> >  1 file changed, 20 insertions(+), 46 deletions(-)
> > 
> > diff --git a/drivers/thermal/devfreq_cooling.c b/drivers/thermal/devfreq_cooling.c
> > index ef59256887ff..3a63603afcf2 100644
> > --- a/drivers/thermal/devfreq_cooling.c
> > +++ b/drivers/thermal/devfreq_cooling.c
> > @@ -24,11 +24,13 @@
> >  #include <linux/idr.h>
> >  #include <linux/slab.h>
> >  #include <linux/pm_opp.h>
> > +#include <linux/pm_qos.h>
> >  #include <linux/thermal.h>
> >  
> >  #include <trace/events/thermal.h>
> >  
> > -#define SCALE_ERROR_MITIGATION 100
> > +#define HZ_PER_KHZ		1000
> > +#define SCALE_ERROR_MITIGATION	100
> >  
> >  static DEFINE_IDA(devfreq_ida);
> >  
> > @@ -65,49 +67,9 @@ struct devfreq_cooling_device {
> >  	struct devfreq_cooling_power *power_ops;
> >  	u32 res_util;
> >  	int capped_state;
> > +	struct dev_pm_qos_request req_max_freq;
> 
> Need to add the description of 'req_max_freq'.

will add the description

> >  };
> >  
> > -/**
> > - * partition_enable_opps() - disable all opps above a given state
> > - * @dfc:	Pointer to devfreq we are operating on
> > - * @cdev_state:	cooling device state we're setting
> > - *
> > - * Go through the OPPs of the device, enabling all OPPs until
> > - * @cdev_state and disabling those frequencies above it.
> > - */
> > -static int partition_enable_opps(struct devfreq_cooling_device *dfc,
> > -				 unsigned long cdev_state)
> > -{
> > -	int i;
> > -	struct device *dev = dfc->devfreq->dev.parent;
> > -
> > -	for (i = 0; i < dfc->freq_table_size; i++) {
> > -		struct dev_pm_opp *opp;
> > -		int ret = 0;
> > -		unsigned int freq = dfc->freq_table[i];
> > -		bool want_enable = i >= cdev_state ? true : false;
> > -
> > -		opp = dev_pm_opp_find_freq_exact(dev, freq, !want_enable);
> > -
> > -		if (PTR_ERR(opp) == -ERANGE)
> > -			continue;
> > -		else if (IS_ERR(opp))
> > -			return PTR_ERR(opp);
> > -
> > -		dev_pm_opp_put(opp);
> > -
> > -		if (want_enable)
> > -			ret = dev_pm_opp_enable(dev, freq);
> > -		else
> > -			ret = dev_pm_opp_disable(dev, freq);
> > -
> > -		if (ret)
> > -			return ret;
> > -	}
> > -
> > -	return 0;
> > -}
> > -
> >  static int devfreq_cooling_get_max_state(struct thermal_cooling_device *cdev,
> >  					 unsigned long *state)
> >  {
> > @@ -134,7 +96,7 @@ static int devfreq_cooling_set_cur_state(struct thermal_cooling_device *cdev,
> >  	struct devfreq_cooling_device *dfc = cdev->devdata;
> >  	struct devfreq *df = dfc->devfreq;
> >  	struct device *dev = df->dev.parent;
> > -	int ret;
> > +	unsigned long freq;
> >  
> >  	if (state == dfc->cooling_state)
> >  		return 0;
> > @@ -144,9 +106,10 @@ static int devfreq_cooling_set_cur_state(struct thermal_cooling_device *cdev,
> >  	if (state >= dfc->freq_table_size)
> >  		return -EINVAL;
> >  
> > -	ret = partition_enable_opps(dfc, state);
> > -	if (ret)
> > -		return ret;
> > +	freq = dfc->freq_table[state];
> > +
> > +	dev_pm_qos_update_request(&dfc->req_max_freq,
> > +				  DIV_ROUND_UP(freq, HZ_PER_KHZ));
> >  
> >  	dfc->cooling_state = state;
> >  
> > @@ -529,6 +492,12 @@ of_devfreq_cooling_register_power(struct device_node *np, struct devfreq *df,
> >  	if (err)
> >  		goto free_dfc;
> >  
> > +	err = dev_pm_qos_add_request(df->dev.parent, &dfc->req_max_freq,
> > +				     DEV_PM_QOS_MAX_FREQUENCY,
> > +				     PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE);
> > +	if (err < 0)
> > +		goto remove_qos_req;
> 
> Jump 'free_table' instead of 'remove_qos_req'.

ack

> > +
> >  	err = ida_simple_get(&devfreq_ida, 0, 0, GFP_KERNEL);
> >  	if (err < 0)
> >  		goto free_tables;
> 
> Jump remove_qos_req.

ack

> > @@ -552,6 +521,10 @@ of_devfreq_cooling_register_power(struct device_node *np, struct devfreq *df,
> >  
> >  release_ida:
> >  	ida_simple_remove(&devfreq_ida, dfc->id);
> > +
> > +remove_qos_req:
> > +	dev_pm_qos_remove_request(&dfc->req_max_freq);
> > +
> >  free_tables:
> >  	kfree(dfc->power_table);
> >  	kfree(dfc->freq_table);
> > @@ -600,6 +573,7 @@ void devfreq_cooling_unregister(struct thermal_cooling_device *cdev)
> >  
> >  	thermal_cooling_device_unregister(dfc->cdev);
> >  	ida_simple_remove(&devfreq_ida, dfc->id);
> > +	dev_pm_qos_remove_request(&dfc->req_max_freq);
> >  	kfree(dfc->power_table);
> >  	kfree(dfc->freq_table);
Matthias Kaehlcke Jan. 14, 2020, 7:07 p.m. UTC | #4
On Tue, Jan 14, 2020 at 04:08:38PM +0000, Leonard Crestez wrote:
> On 10.01.2020 19:49, Matthias Kaehlcke wrote:
> > Now that devfreq supports limiting the frequency range of a device
> > through PM QoS make use of it instead of disabling OPPs that should
> > not be used.
> > 
> > Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
> > ---
> 
> It is not obvious but this changes behavior when min max requests 
> conflict (min > max): with PM QoS a MIN_FREQUENCY request takes 
> precedence but if higher OPPs are disabled then this will override 
> MIN_FREQUENCY.

Thanks for pointing this out.

> There are very few users of this functionality so I don't think there 
> are any systems that depend on this behaving one way or the other but 
> perhaps it should be mentioned in commit message?

Sounds good, I'll add a note.

> As far as I can tell the only user of devfreq_cooling in upstream is 
> drivers/gpu/drm/panfrost?

Indeed, apparently GPUs are the primary devfreq device used for cooling,
and unfortunately most GPU drivers are not in upstream.

> >   drivers/thermal/devfreq_cooling.c | 66 ++++++++++---------------------
> >   1 file changed, 20 insertions(+), 46 deletions(-)
> > 
> > diff --git a/drivers/thermal/devfreq_cooling.c b/drivers/thermal/devfreq_cooling.c
> > index ef59256887ff..3a63603afcf2 100644
> > --- a/drivers/thermal/devfreq_cooling.c
> > +++ b/drivers/thermal/devfreq_cooling.c
> > @@ -24,11 +24,13 @@
> >   #include <linux/idr.h>
> >   #include <linux/slab.h>
> >   #include <linux/pm_opp.h>
> > +#include <linux/pm_qos.h>
> >   #include <linux/thermal.h>
> >   
> >   #include <trace/events/thermal.h>
> >   
> > -#define SCALE_ERROR_MITIGATION 100
> > +#define HZ_PER_KHZ		1000
> > +#define SCALE_ERROR_MITIGATION	100
> >   
> >   static DEFINE_IDA(devfreq_ida);
> >   
> > @@ -65,49 +67,9 @@ struct devfreq_cooling_device {
> >   	struct devfreq_cooling_power *power_ops;
> >   	u32 res_util;
> >   	int capped_state;
> > +	struct dev_pm_qos_request req_max_freq;
> >   };
> >   
> > -/**
> > - * partition_enable_opps() - disable all opps above a given state
> > - * @dfc:	Pointer to devfreq we are operating on
> > - * @cdev_state:	cooling device state we're setting
> > - *
> > - * Go through the OPPs of the device, enabling all OPPs until
> > - * @cdev_state and disabling those frequencies above it.
> > - */
> > -static int partition_enable_opps(struct devfreq_cooling_device *dfc,
> > -				 unsigned long cdev_state)
> > -{
> > -	int i;
> > -	struct device *dev = dfc->devfreq->dev.parent;
> > -
> > -	for (i = 0; i < dfc->freq_table_size; i++) {
> > -		struct dev_pm_opp *opp;
> > -		int ret = 0;
> > -		unsigned int freq = dfc->freq_table[i];
> > -		bool want_enable = i >= cdev_state ? true : false;
> > -
> > -		opp = dev_pm_opp_find_freq_exact(dev, freq, !want_enable);
> > -
> > -		if (PTR_ERR(opp) == -ERANGE)
> > -			continue;
> > -		else if (IS_ERR(opp))
> > -			return PTR_ERR(opp);
> > -
> > -		dev_pm_opp_put(opp);
> > -
> > -		if (want_enable)
> > -			ret = dev_pm_opp_enable(dev, freq);
> > -		else
> > -			ret = dev_pm_opp_disable(dev, freq);
> > -
> > -		if (ret)
> > -			return ret;
> > -	}
> > -
> > -	return 0;
> > -}
> > -
> >   static int devfreq_cooling_get_max_state(struct thermal_cooling_device *cdev,
> >   					 unsigned long *state)
> >   {
> > @@ -134,7 +96,7 @@ static int devfreq_cooling_set_cur_state(struct thermal_cooling_device *cdev,
> >   	struct devfreq_cooling_device *dfc = cdev->devdata;
> >   	struct devfreq *df = dfc->devfreq;
> >   	struct device *dev = df->dev.parent;
> > -	int ret;
> > +	unsigned long freq;
> >   
> >   	if (state == dfc->cooling_state)
> >   		return 0;
> > @@ -144,9 +106,10 @@ static int devfreq_cooling_set_cur_state(struct thermal_cooling_device *cdev,
> >   	if (state >= dfc->freq_table_size)
> >   		return -EINVAL;
> >   
> > -	ret = partition_enable_opps(dfc, state);
> > -	if (ret)
> > -		return ret;
> > +	freq = dfc->freq_table[state];
> > +
> > +	dev_pm_qos_update_request(&dfc->req_max_freq,
> > +				  DIV_ROUND_UP(freq, HZ_PER_KHZ));
> >   
> >   	dfc->cooling_state = state;
> >   
> > @@ -529,6 +492,12 @@ of_devfreq_cooling_register_power(struct device_node *np, struct devfreq *df,
> >   	if (err)
> >   		goto free_dfc;
> >   
> > +	err = dev_pm_qos_add_request(df->dev.parent, &dfc->req_max_freq,
> > +				     DEV_PM_QOS_MAX_FREQUENCY,
> > +				     PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE);
> > +	if (err < 0)
> > +		goto remove_qos_req;
> > +
> >   	err = ida_simple_get(&devfreq_ida, 0, 0, GFP_KERNEL);
> >   	if (err < 0)
> >   		goto free_tables;
> > @@ -552,6 +521,10 @@ of_devfreq_cooling_register_power(struct device_node *np, struct devfreq *df,
> >   
> >   release_ida:
> >   	ida_simple_remove(&devfreq_ida, dfc->id);
> > +
> > +remove_qos_req:
> > +	dev_pm_qos_remove_request(&dfc->req_max_freq); > +
> 
> A quirk of the dev_pm_qos API is that dev_pm_qos_remove_request prints a 
> WARN splat if !dev_pm_qos_request_active and this can true on 
> dev_pm_qos_add_request error.
> 
> I dealt with this by checking dev_pm_qos_request_active explicitly but 
> perhaps dev_pm_qos API could be changed? In general "free/release" 
> functions shouldn't complain if there's nothing to do.

I think we should be good here if we jump to 'free_tables' if
_add_request() fails, as requested by Chanwoo. Then _remove_request() is
only called when _add_request() was successful.

> >   free_tables:
> >   	kfree(dfc->power_table);
> >   	kfree(dfc->freq_table);
> > @@ -600,6 +573,7 @@ void devfreq_cooling_unregister(struct thermal_cooling_device *cdev)
> >   
> >   	thermal_cooling_device_unregister(dfc->cdev);
> >   	ida_simple_remove(&devfreq_ida, dfc->id);
> > +	dev_pm_qos_remove_request(&dfc->req_max_freq);
> >   	kfree(dfc->power_table);
> >   	kfree(dfc->freq_table);
diff mbox series

Patch

diff --git a/drivers/thermal/devfreq_cooling.c b/drivers/thermal/devfreq_cooling.c
index ef59256887ff..3a63603afcf2 100644
--- a/drivers/thermal/devfreq_cooling.c
+++ b/drivers/thermal/devfreq_cooling.c
@@ -24,11 +24,13 @@ 
 #include <linux/idr.h>
 #include <linux/slab.h>
 #include <linux/pm_opp.h>
+#include <linux/pm_qos.h>
 #include <linux/thermal.h>
 
 #include <trace/events/thermal.h>
 
-#define SCALE_ERROR_MITIGATION 100
+#define HZ_PER_KHZ		1000
+#define SCALE_ERROR_MITIGATION	100
 
 static DEFINE_IDA(devfreq_ida);
 
@@ -65,49 +67,9 @@  struct devfreq_cooling_device {
 	struct devfreq_cooling_power *power_ops;
 	u32 res_util;
 	int capped_state;
+	struct dev_pm_qos_request req_max_freq;
 };
 
-/**
- * partition_enable_opps() - disable all opps above a given state
- * @dfc:	Pointer to devfreq we are operating on
- * @cdev_state:	cooling device state we're setting
- *
- * Go through the OPPs of the device, enabling all OPPs until
- * @cdev_state and disabling those frequencies above it.
- */
-static int partition_enable_opps(struct devfreq_cooling_device *dfc,
-				 unsigned long cdev_state)
-{
-	int i;
-	struct device *dev = dfc->devfreq->dev.parent;
-
-	for (i = 0; i < dfc->freq_table_size; i++) {
-		struct dev_pm_opp *opp;
-		int ret = 0;
-		unsigned int freq = dfc->freq_table[i];
-		bool want_enable = i >= cdev_state ? true : false;
-
-		opp = dev_pm_opp_find_freq_exact(dev, freq, !want_enable);
-
-		if (PTR_ERR(opp) == -ERANGE)
-			continue;
-		else if (IS_ERR(opp))
-			return PTR_ERR(opp);
-
-		dev_pm_opp_put(opp);
-
-		if (want_enable)
-			ret = dev_pm_opp_enable(dev, freq);
-		else
-			ret = dev_pm_opp_disable(dev, freq);
-
-		if (ret)
-			return ret;
-	}
-
-	return 0;
-}
-
 static int devfreq_cooling_get_max_state(struct thermal_cooling_device *cdev,
 					 unsigned long *state)
 {
@@ -134,7 +96,7 @@  static int devfreq_cooling_set_cur_state(struct thermal_cooling_device *cdev,
 	struct devfreq_cooling_device *dfc = cdev->devdata;
 	struct devfreq *df = dfc->devfreq;
 	struct device *dev = df->dev.parent;
-	int ret;
+	unsigned long freq;
 
 	if (state == dfc->cooling_state)
 		return 0;
@@ -144,9 +106,10 @@  static int devfreq_cooling_set_cur_state(struct thermal_cooling_device *cdev,
 	if (state >= dfc->freq_table_size)
 		return -EINVAL;
 
-	ret = partition_enable_opps(dfc, state);
-	if (ret)
-		return ret;
+	freq = dfc->freq_table[state];
+
+	dev_pm_qos_update_request(&dfc->req_max_freq,
+				  DIV_ROUND_UP(freq, HZ_PER_KHZ));
 
 	dfc->cooling_state = state;
 
@@ -529,6 +492,12 @@  of_devfreq_cooling_register_power(struct device_node *np, struct devfreq *df,
 	if (err)
 		goto free_dfc;
 
+	err = dev_pm_qos_add_request(df->dev.parent, &dfc->req_max_freq,
+				     DEV_PM_QOS_MAX_FREQUENCY,
+				     PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE);
+	if (err < 0)
+		goto remove_qos_req;
+
 	err = ida_simple_get(&devfreq_ida, 0, 0, GFP_KERNEL);
 	if (err < 0)
 		goto free_tables;
@@ -552,6 +521,10 @@  of_devfreq_cooling_register_power(struct device_node *np, struct devfreq *df,
 
 release_ida:
 	ida_simple_remove(&devfreq_ida, dfc->id);
+
+remove_qos_req:
+	dev_pm_qos_remove_request(&dfc->req_max_freq);
+
 free_tables:
 	kfree(dfc->power_table);
 	kfree(dfc->freq_table);
@@ -600,6 +573,7 @@  void devfreq_cooling_unregister(struct thermal_cooling_device *cdev)
 
 	thermal_cooling_device_unregister(dfc->cdev);
 	ida_simple_remove(&devfreq_ida, dfc->id);
+	dev_pm_qos_remove_request(&dfc->req_max_freq);
 	kfree(dfc->power_table);
 	kfree(dfc->freq_table);