PM / devfreq: add min/max_freq limit requested by users.

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>

5 files changed, 96 insertions, 8 deletions

diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index c189b82f5ec..a129a7b6bfd 100644
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -501,12 +501,82 @@ 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 c0596b29176..574a06b1b1d 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 2483a85a266..d742d4a82d6 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 efad8dcf902..a2e3eae7901 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 4f8b563da78..0681246fc89 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;
 }