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Subject[PATCH 1/2] PM / devfreq: add min/max_freq limit requested by users.
Date
The frequency requested to devfreq device driver from devfreq governors
is restricted by min_freq and max_freq input.

Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
---
drivers/devfreq/devfreq.c | 70 +++++++++++++++++++++++++++++
drivers/devfreq/governor_performance.c | 5 ++-
drivers/devfreq/governor_powersave.c | 2 +-
drivers/devfreq/governor_simpleondemand.c | 12 ++++-
drivers/devfreq/governor_userspace.c | 15 +++++-
include/linux/devfreq.h | 5 ++
6 files changed, 101 insertions(+), 8 deletions(-)

diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index 59d24e9..358d129 100644
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -502,12 +502,82 @@ static ssize_t show_central_polling(struct device *dev,
!to_devfreq(dev)->governor->no_central_polling);
}

+static ssize_t store_min_freq(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct devfreq *df = to_devfreq(dev);
+ unsigned long value;
+ int ret;
+ unsigned long max;
+
+ ret = sscanf(buf, "%lu", &value);
+ if (ret != 1)
+ goto out;
+
+ mutex_lock(&df->lock);
+ max = df->max_freq;
+ if (value && max && value > max) {
+ ret = -EINVAL;
+ goto unlock;
+ }
+
+ df->min_freq = value;
+ update_devfreq(df);
+ ret = count;
+unlock:
+ mutex_unlock(&df->lock);
+out:
+ return ret;
+}
+
+static ssize_t show_min_freq(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ return sprintf(buf, "%lu\n", to_devfreq(dev)->min_freq);
+}
+
+static ssize_t store_max_freq(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct devfreq *df = to_devfreq(dev);
+ unsigned long value;
+ int ret;
+ unsigned long min;
+
+ ret = sscanf(buf, "%lu", &value);
+ if (ret != 1)
+ goto out;
+
+ mutex_lock(&df->lock);
+ min = df->min_freq;
+ if (value && min && value < min) {
+ ret = -EINVAL;
+ goto unlock;
+ }
+
+ df->max_freq = value;
+ update_devfreq(df);
+ ret = count;
+unlock:
+ mutex_unlock(&df->lock);
+out:
+ return ret;
+}
+
+static ssize_t show_max_freq(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ return sprintf(buf, "%lu\n", to_devfreq(dev)->max_freq);
+}
+
static struct device_attribute devfreq_attrs[] = {
__ATTR(governor, S_IRUGO, show_governor, NULL),
__ATTR(cur_freq, S_IRUGO, show_freq, NULL),
__ATTR(central_polling, S_IRUGO, show_central_polling, NULL),
__ATTR(polling_interval, S_IRUGO | S_IWUSR, show_polling_interval,
store_polling_interval),
+ __ATTR(min_freq, S_IRUGO | S_IWUSR, show_min_freq, store_min_freq),
+ __ATTR(max_freq, S_IRUGO | S_IWUSR, show_max_freq, store_max_freq),
{ },
};

diff --git a/drivers/devfreq/governor_performance.c b/drivers/devfreq/governor_performance.c
index c0596b2..574a06b 100644
--- a/drivers/devfreq/governor_performance.c
+++ b/drivers/devfreq/governor_performance.c
@@ -18,7 +18,10 @@ static int devfreq_performance_func(struct devfreq *df,
* target callback should be able to get floor value as
* said in devfreq.h
*/
- *freq = UINT_MAX;
+ if (!df->max_freq)
+ *freq = UINT_MAX;
+ else
+ *freq = df->max_freq;
return 0;
}

diff --git a/drivers/devfreq/governor_powersave.c b/drivers/devfreq/governor_powersave.c
index 2483a85..d742d4a 100644
--- a/drivers/devfreq/governor_powersave.c
+++ b/drivers/devfreq/governor_powersave.c
@@ -18,7 +18,7 @@ static int devfreq_powersave_func(struct devfreq *df,
* target callback should be able to get ceiling value as
* said in devfreq.h
*/
- *freq = 0;
+ *freq = df->min_freq;
return 0;
}

diff --git a/drivers/devfreq/governor_simpleondemand.c b/drivers/devfreq/governor_simpleondemand.c
index efad8dc..a2e3eae 100644
--- a/drivers/devfreq/governor_simpleondemand.c
+++ b/drivers/devfreq/governor_simpleondemand.c
@@ -25,6 +25,7 @@ static int devfreq_simple_ondemand_func(struct devfreq *df,
unsigned int dfso_upthreshold = DFSO_UPTHRESHOLD;
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;

if (err)
return err;
@@ -41,7 +42,7 @@ static int devfreq_simple_ondemand_func(struct devfreq *df,

/* Assume MAX if it is going to be divided by zero */
if (stat.total_time == 0) {
- *freq = UINT_MAX;
+ *freq = max;
return 0;
}

@@ -54,13 +55,13 @@ static int devfreq_simple_ondemand_func(struct devfreq *df,
/* Set MAX if it's busy enough */
if (stat.busy_time * 100 >
stat.total_time * dfso_upthreshold) {
- *freq = UINT_MAX;
+ *freq = max;
return 0;
}

/* Set MAX if we do not know the initial frequency */
if (stat.current_frequency == 0) {
- *freq = UINT_MAX;
+ *freq = max;
return 0;
}

@@ -79,6 +80,11 @@ static int devfreq_simple_ondemand_func(struct devfreq *df,
b = div_u64(b, (dfso_upthreshold - dfso_downdifferential / 2));
*freq = (unsigned long) b;

+ if (df->min_freq && *freq < df->min_freq)
+ *freq = df->min_freq;
+ if (df->max_freq && *freq > df->max_freq)
+ *freq = df->max_freq;
+
return 0;
}

diff --git a/drivers/devfreq/governor_userspace.c b/drivers/devfreq/governor_userspace.c
index 4f8b563..0681246 100644
--- a/drivers/devfreq/governor_userspace.c
+++ b/drivers/devfreq/governor_userspace.c
@@ -25,10 +25,19 @@ static int devfreq_userspace_func(struct devfreq *df, unsigned long *freq)
{
struct userspace_data *data = df->data;

- if (!data->valid)
+ if (data->valid) {
+ unsigned long adjusted_freq = data->user_frequency;
+
+ if (df->max_freq && adjusted_freq > df->max_freq)
+ adjusted_freq = df->max_freq;
+
+ if (df->min_freq && adjusted_freq < df->min_freq)
+ adjusted_freq = df->min_freq;
+
+ *freq = adjusted_freq;
+ } else {
*freq = df->previous_freq; /* No user freq specified yet */
- else
- *freq = data->user_frequency;
+ }
return 0;
}

diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h
index 98ce812..e9385bf 100644
--- a/include/linux/devfreq.h
+++ b/include/linux/devfreq.h
@@ -124,6 +124,8 @@ struct devfreq_governor {
* touch this.
* @being_removed a flag to mark that this object is being removed in
* order to prevent trying to remove the object multiple times.
+ * @min_freq Limit minimum frequency requested by user (0: none)
+ * @max_freq Limit maximum frequency requested by user (0: none)
*
* This structure stores the devfreq information for a give device.
*
@@ -149,6 +151,9 @@ struct devfreq {
void *data; /* private data for governors */

bool being_removed;
+
+ unsigned long min_freq;
+ unsigned long max_freq;
};

#if defined(CONFIG_PM_DEVFREQ)
--
1.7.4.1


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