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Commit 4b185480 authored by Sahitya Tummala's avatar Sahitya Tummala Committed by Channagoud Kadabi
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PM / devfreq: Add new flag to do simple clock scaling 



Add new flag "simple_scaling" to on demand governor so that
the clocks can be scaled up only when the load is more than
up threshold and can be scaled down only when the load is less
than down differential data as provided within
struct devfreq_simple_ondemand_data.

Change-Id: Ibc6ab6297c1b64b6e6eaaa76d735d0b9ae0f6477
Signed-off-by: default avatarSahitya Tummala <stummala@codeaurora.org>
[venkatg@codeaurora.org: dereference stat variables]
Signed-off-by: default avatarVenkat Gopalakrishnan <venkatg@codeaurora.org>
parent 7ce751bf

drivers/devfreq/governor_simpleondemand.c

+19 −6
Original line number Diff line number Diff line
@@ -28,6 +28,7 @@ static int devfreq_simple_ondemand_func(struct devfreq *df, 
	unsigned int dfso_downdifferential = DFSO_DOWNDIFFERENCTIAL;

	struct devfreq_simple_ondemand_data *data = df->data;

	unsigned long max = (df->max_freq) ? df->max_freq : UINT_MAX;

	unsigned long min = (df->min_freq) ? df->min_freq : 0;



	err = devfreq_update_stats(df);

	if (err)
@@ -45,18 +46,30 @@ static int devfreq_simple_ondemand_func(struct devfreq *df, 
	    dfso_upthreshold < dfso_downdifferential)

		return -EINVAL;



	/* Assume MAX if it is going to be divided by zero */

	if (stat->total_time == 0) {

		*freq = max;

		return 0;

	}



	/* Prevent overflow */

	if (stat->busy_time >= (1 << 24) || stat->total_time >= (1 << 24)) {

		stat->busy_time >>= 7;

		stat->total_time >>= 7;

	}



	if (data && data->simple_scaling) {

		if (stat->busy_time * 100 >

		    stat->total_time * dfso_upthreshold)

			*freq = max;

		else if (stat->busy_time * 100 <

		    stat->total_time * dfso_downdifferential)

			*freq = min;

		else

			*freq = df->previous_freq;

		return 0;

	}



	/* Assume MAX if it is going to be divided by zero */

	if (stat->total_time == 0) {

		*freq = max;

		return 0;

	}



	/* Set MAX if it's busy enough */

	if (stat->busy_time * 100 >

	    stat->total_time * dfso_upthreshold) {

include/linux/devfreq.h

+4 −0
Original line number Diff line number Diff line
@@ -262,6 +262,9 @@ static inline int devfreq_update_stats(struct devfreq *df) 
 *			the governor may consider slowing the frequency down.

 *			Specify 0 to use the default. Valid value = 0 to 100.

 *			downdifferential < upthreshold must hold.

 * @simple_scaling:	Setting this flag will scale the clocks up only if the

 *			load is above @upthreshold and will scale the clocks

 *			down only if the load is below @downdifferential.

 *

 * If the fed devfreq_simple_ondemand_data pointer is NULL to the governor,

 * the governor uses the default values.
@@ -269,6 +272,7 @@ static inline int devfreq_update_stats(struct devfreq *df) 
struct devfreq_simple_ondemand_data {

	unsigned int upthreshold;

	unsigned int downdifferential;

	unsigned int simple_scaling;

};

#endif