diff --git a/Documentation/ABI/testing/sysfs-class-devfreq b/Documentation/ABI/testing/sysfs-class-devfreq
index e672ccb02e7fb180f1871ed6a932adb87fbb3716..40f98a9428dce6f3380170e60b6f72e8257c1543 100644
--- a/Documentation/ABI/testing/sysfs-class-devfreq
+++ b/Documentation/ABI/testing/sysfs-class-devfreq
@@ -44,6 +44,17 @@ Description:
(/sys/class/devfreq/.../central_polling is 0), this value
may be useless.
+What: /sys/class/devfreq/.../trans_stat
+Date: October 2012
+Contact: MyungJoo Ham <myungjoo.ham@samsung.com>
+Descrtiption:
+ This ABI shows the statistics of devfreq behavior on a
+ specific device. It shows the time spent in each state and
+ the number of transitions between states.
+ In order to activate this ABI, the devfreq target device
+ driver should provide the list of available frequencies
+ with its profile.
+
What: /sys/class/devfreq/.../userspace/set_freq
Date: September 2011
Contact: MyungJoo Ham <myungjoo.ham@samsung.com>
diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index c44e562bdfe08ffa2f084aab0570d162f285a924..bf6de38190cf5ff19a867e2515b4cb47e9ed515b 100644
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -66,6 +66,51 @@ static struct devfreq *find_device_devfreq(struct device *dev)
return ERR_PTR(-ENODEV);
}
+/**
+ * devfreq_get_freq_level() - Lookup freq_table for the frequency
+ * @devfreq: the devfreq instance
+ * @freq: the target frequency
+ */
+static int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq)
+{
+ int lev;
+
+ for (lev = 0; lev < devfreq->profile->max_state; lev++)
+ if (freq == devfreq->profile->freq_table[lev])
+ return lev;
+
+ return -EINVAL;
+}
+
+/**
+ * devfreq_update_status() - Update statistics of devfreq behavior
+ * @devfreq: the devfreq instance
+ * @freq: the update target frequency
+ */
+static int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
+{
+ int lev, prev_lev;
+ unsigned long cur_time;
+
+ lev = devfreq_get_freq_level(devfreq, freq);
+ if (lev < 0)
+ return lev;
+
+ cur_time = jiffies;
+ devfreq->time_in_state[lev] +=
+ cur_time - devfreq->last_stat_updated;
+ if (freq != devfreq->previous_freq) {
+ prev_lev = devfreq_get_freq_level(devfreq,
+ devfreq->previous_freq);
+ devfreq->trans_table[(prev_lev *
+ devfreq->profile->max_state) + lev]++;
+ devfreq->total_trans++;
+ }
+ devfreq->last_stat_updated = cur_time;
+
+ return 0;
+}
+
/* Load monitoring helper functions for governors use */
/**
@@ -112,6 +157,11 @@ int update_devfreq(struct devfreq *devfreq)
if (err)
return err;
+ if (devfreq->profile->freq_table)
+ if (devfreq_update_status(devfreq, freq))
+ dev_err(&devfreq->dev,
+ "Couldn't update frequency transition information.\n");
+
devfreq->previous_freq = freq;
return err;
}
@@ -378,6 +428,15 @@ struct devfreq *devfreq_add_device(struct device *dev,
devfreq->data = data;
devfreq->nb.notifier_call = devfreq_notifier_call;
+ devfreq->trans_table = devm_kzalloc(dev, sizeof(unsigned int) *
+ devfreq->profile->max_state *
+ devfreq->profile->max_state,
+ GFP_KERNEL);
+ devfreq->time_in_state = devm_kzalloc(dev, sizeof(unsigned int) *
+ devfreq->profile->max_state,
+ GFP_KERNEL);
+ devfreq->last_stat_updated = jiffies;
+
dev_set_name(&devfreq->dev, dev_name(dev));
err = device_register(&devfreq->dev);
if (err) {
@@ -601,6 +660,47 @@ static ssize_t show_available_freqs(struct device *d,
return count;
}
+static ssize_t show_trans_table(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ struct devfreq *devfreq = to_devfreq(dev);
+ ssize_t len;
+ int i, j, err;
+ unsigned int max_state = devfreq->profile->max_state;
+
+ err = devfreq_update_status(devfreq, devfreq->previous_freq);
+ if (err)
+ return 0;
+
+ len = sprintf(buf, " From : To\n");
+ len += sprintf(buf + len, " :");
+ for (i = 0; i < max_state; i++)
+ len += sprintf(buf + len, "%8u",
+ devfreq->profile->freq_table[i]);
+
+ len += sprintf(buf + len, " time(ms)\n");
+
+ for (i = 0; i < max_state; i++) {
+ if (devfreq->profile->freq_table[i]
+ == devfreq->previous_freq) {
+ len += sprintf(buf + len, "*");
+ } else {
+ len += sprintf(buf + len, " ");
+ }
+ len += sprintf(buf + len, "%8u:",
+ devfreq->profile->freq_table[i]);
+ for (j = 0; j < max_state; j++)
+ len += sprintf(buf + len, "%8u",
+ devfreq->trans_table[(i * max_state) + j]);
+ len += sprintf(buf + len, "%10u\n",
+ jiffies_to_msecs(devfreq->time_in_state[i]));
+ }
+
+ len += sprintf(buf + len, "Total transition : %u\n",
+ devfreq->total_trans);
+ return len;
+}
+
static struct device_attribute devfreq_attrs[] = {
__ATTR(governor, S_IRUGO, show_governor, NULL),
__ATTR(cur_freq, S_IRUGO, show_freq, NULL),
@@ -610,6 +710,7 @@ static struct device_attribute devfreq_attrs[] = {
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),
+ __ATTR(trans_stat, S_IRUGO, show_trans_table, NULL),
{ },
};
diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h
index 1461fb2355ad4f1470ee8c3fa00614287a79b052..bc35c4aee6a38b420fffc9ece7a5fa94dd0f439c 100644
--- a/include/linux/devfreq.h
+++ b/include/linux/devfreq.h
@@ -73,6 +73,8 @@ struct devfreq_dev_status {
* from devfreq_remove_device() call. If the user
* has registered devfreq->nb at a notifier-head,
* this is the time to unregister it.
+ * @freq_table: Optional list of frequencies to support statistics.
+ * @max_state: The size of freq_table.
*/
struct devfreq_dev_profile {
unsigned long initial_freq;
@@ -83,6 +85,9 @@ struct devfreq_dev_profile {
struct devfreq_dev_status *stat);
int (*get_cur_freq)(struct device *dev, unsigned long *freq);
void (*exit)(struct device *dev);
+
+ unsigned int *freq_table;
+ unsigned int max_state;
};
/**
@@ -127,6 +132,10 @@ struct devfreq_governor {
* @min_freq: Limit minimum frequency requested by user (0: none)
* @max_freq: Limit maximum frequency requested by user (0: none)
* @stop_polling: devfreq polling status of a device.
+ * @total_trans: Number of devfreq transitions
+ * @trans_table: Statistics of devfreq transitions
+ * @time_in_state: Statistics of devfreq states
+ * @last_stat_updated: The last time stat updated
*
* This structure stores the devfreq information for a give device.
*
@@ -153,6 +162,12 @@ struct devfreq {
unsigned long min_freq;
unsigned long max_freq;
bool stop_polling;
+
+ /* information for device freqeuncy transition */
+ unsigned int total_trans;
+ unsigned int *trans_table;
+ unsigned long *time_in_state;
+ unsigned long last_stat_updated;
};
#if defined(CONFIG_PM_DEVFREQ)