Re: [PATCH v10 09/11] PM / devfreq: Introduce get_freq_range helper

[Leonard Crestez <leonard.crestez@nxp.com>]

On Mon, 2019-11-11 at 14:56 +0900, Chanwoo Choi wrote:
> On 11/1/19 6:34 AM, Leonard Crestez wrote:
> > Moving handling of min/max freq to a single function and call it from
> > update_devfreq and for printing min/max freq values in sysfs.
> > 
> > This changes the behavior of out-of-range min_freq/max_freq: clamping
> > is now done at evaluation time. This means that if an out-of-range
> > constraint is imposed by sysfs and it later becomes valid then it will
> > be enforced.
> > 
> > Signed-off-by: Leonard Crestez <leonard.crestez@nxp.com>
> > Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
> > Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com>
> > ---
> >  drivers/devfreq/devfreq.c | 108 +++++++++++++++++++++-----------------
> >  1 file changed, 60 insertions(+), 48 deletions(-)
> > 
> > diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
> > index ab12fd22aa08..ba3b53ee23fd 100644
> > --- a/drivers/devfreq/devfreq.c
> > +++ b/drivers/devfreq/devfreq.c
> > @@ -96,10 +96,51 @@ static unsigned long find_available_max_freq(struct devfreq *devfreq)
> >  		dev_pm_opp_put(opp);
> >  
> >  	return max_freq;
> >  }
> >  
> > +/**
> > + * get_freq_range() - Get the current freq range
> > + * @devfreq:	the devfreq instance
> > + * @min_freq:	the min frequency
> > + * @max_freq:	the max frequency
> > + *
> > + * This takes into consideration all constraints.
> > + */
> > +static void get_freq_range(struct devfreq *devfreq,
> > +			   unsigned long *min_freq,
> > +			   unsigned long *max_freq)
> > +{
> > +	unsigned long *freq_table = devfreq->profile->freq_table;
> > +
> > +	lockdep_assert_held(&devfreq->lock);
> > +
> > +	/*
> > +	 * Initialize minimum/maximum frequency from freq table.
> > +	 * The devfreq drivers can initialize this in either ascending or
> > +	 * descending order and devfreq core supports both.
> > +	 */
> > +	if (freq_table[0] < freq_table[devfreq->profile->max_state - 1]) {
> > +		*min_freq = freq_table[0];
> > +		*max_freq = freq_table[devfreq->profile->max_state - 1];
> > +	} else {
> > +		*min_freq = freq_table[devfreq->profile->max_state - 1];
> > +		*max_freq = freq_table[0];
> > +	}
> > +
> > +	/* Apply constraints from sysfs */
> > +	*min_freq = max(*min_freq, devfreq->min_freq);
> > +	*max_freq = min(*max_freq, devfreq->max_freq);
> > +
> > +	/* Apply constraints from OPP interface */
> > +	*min_freq = max(*min_freq, devfreq->scaling_min_freq);
> > +	*max_freq = min(*max_freq, devfreq->scaling_max_freq);
> > +
> > +	if (*min_freq > *max_freq)
> > +		*min_freq = *max_freq;
> > +}
> > +
> >  /**
> >   * devfreq_get_freq_level() - Lookup freq_table for the frequency
> >   * @devfreq:	the devfreq instance
> >   * @freq:	the target frequency
> >   */
> > @@ -348,20 +389,11 @@ int update_devfreq(struct devfreq *devfreq)
> >  
> >  	/* Reevaluate the proper frequency */
> >  	err = devfreq->governor->get_target_freq(devfreq, &freq);
> >  	if (err)
> >  		return err;
> > -
> > -	/*
> > -	 * Adjust the frequency with user freq, QoS and available freq.
> > -	 *
> > -	 * List from the highest priority
> > -	 * max_freq
> > -	 * min_freq
> > -	 */
> > -	max_freq = min(devfreq->scaling_max_freq, devfreq->max_freq);
> > -	min_freq = max(devfreq->scaling_min_freq, devfreq->min_freq);
> > +	get_freq_range(devfreq, &min_freq, &max_freq);
> >  
> >  	if (freq < min_freq) {
> >  		freq = min_freq;
> >  		flags &= ~DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use GLB */
> >  	}
> > @@ -1292,40 +1324,28 @@ static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr,
> >  	ret = sscanf(buf, "%lu", &value);
> >  	if (ret != 1)
> >  		return -EINVAL;
> >  
> >  	mutex_lock(&df->lock);
> > -
> > -	if (value) {
> > -		if (value > df->max_freq) {
> > -			ret = -EINVAL;
> > -			goto unlock;
> > -		}
> > -	} else {
> > -		unsigned long *freq_table = df->profile->freq_table;
> > -
> > -		/* Get minimum frequency according to sorting order */
> > -		if (freq_table[0] < freq_table[df->profile->max_state - 1])
> > -			value = freq_table[0];
> > -		else
> > -			value = freq_table[df->profile->max_state - 1];
> > -	}
> > -
> >  	df->min_freq = value;
> >  	update_devfreq(df);
> > -	ret = count;
> > -unlock:
> >  	mutex_unlock(&df->lock);
> > -	return ret;
> > +
> > +	return count;
> >  }
> >  
> >  static ssize_t min_freq_show(struct device *dev, struct device_attribute *attr,
> >  			     char *buf)
> >  {
> >  	struct devfreq *df = to_devfreq(dev);
> > +	unsigned long min_freq, max_freq;
> >  
> > -	return sprintf(buf, "%lu\n", max(df->scaling_min_freq, df->min_freq));
> > +	mutex_lock(&df->lock);
> > +	get_freq_range(df, &min_freq, &max_freq);
> > +	mutex_unlock(&df->lock);
> > +
> > +	return sprintf(buf, "%lu\n", min_freq);
> >  }
> >  
> >  static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
> >  			      const char *buf, size_t count)
> >  {
> > @@ -1337,40 +1357,32 @@ static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
> >  	if (ret != 1)
> >  		return -EINVAL;
> >  
> >  	mutex_lock(&df->lock);
> >  
> > -	if (value) {
> > -		if (value < df->min_freq) {
> > -			ret = -EINVAL;
> > -			goto unlock;
> > -		}
> > -	} else {
> > -		unsigned long *freq_table = df->profile->freq_table;
> > -
> > -		/* Get maximum frequency according to sorting order */
> > -		if (freq_table[0] < freq_table[df->profile->max_state - 1])
> > -			value = freq_table[df->profile->max_state - 1];
> > -		else
> > -			value = freq_table[0];
> > -	}
> > +	if (!value)
> > +		value = ULONG_MAX;
> >  
> >  	df->max_freq = value;
> >  	update_devfreq(df);
> > -	ret = count;
> > -unlock:
> >  	mutex_unlock(&df->lock);
> > -	return ret;
> > +
> > +	return count;
> >  }
> >  static DEVICE_ATTR_RW(min_freq);
> >  
> >  static ssize_t max_freq_show(struct device *dev, struct device_attribute *attr,
> >  			     char *buf)
> >  {
> >  	struct devfreq *df = to_devfreq(dev);
> > +	unsigned long min_freq, max_freq;
> > +
> > +	mutex_lock(&df->lock);
> > +	get_freq_range(df, &min_freq, &max_freq);
> > +	mutex_unlock(&df->lock);
> >  
> > -	return sprintf(buf, "%lu\n", min(df->scaling_max_freq, df->max_freq));
> > +	return sprintf(buf, "%lu\n", max_freq);
> >  }
> >  static DEVICE_ATTR_RW(max_freq);
> >  
> >  static ssize_t available_frequencies_show(struct device *d,
> >  					  struct device_attribute *attr,
> > 
> 
> Applied it because it doesn't depend on the pm_qos feature.

Thanks, this will make it easier to move forward.

--
Regards,
Leonard
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