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Subject[PATCH v2 3/3] PM / DEVFREQ: add sysfs interface (including user tickling)
1. System-wide sysfs interface
- tickle_all R: number of tickle_all execution
W: tickle all devfreq devices
- min_interval R: devfreq monitoring base interval in ms
- monitoring R: shows whether devfreq monitoring is active or
not.

2. Device specific sysfs interface
- tickle R: number of tickle execution for the device
W: tickle the device

Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
---
drivers/base/power/devfreq.c | 191 ++++++++++++++++++++++++++++++++++++-----
include/linux/devfreq.h | 3 +
2 files changed, 170 insertions(+), 24 deletions(-)
diff --git a/drivers/base/power/devfreq.c b/drivers/base/power/devfreq.c
index 251d761..ba1b606 100644
--- a/drivers/base/power/devfreq.c
+++ b/drivers/base/power/devfreq.c
@@ -40,6 +40,9 @@ static LIST_HEAD(devfreq_list);
/* Exclusive access to devfreq_list and its elements */
static DEFINE_MUTEX(devfreq_list_lock);

+static struct kobject *devfreq_kobj;
+static struct attribute_group dev_attr_group;
+
/**
* find_device_devfreq() - find devfreq struct using device pointer
* @dev: device pointer used to lookup device DEVFREQ.
@@ -211,6 +214,8 @@ int devfreq_add_device(struct device *dev, struct devfreq_dev_profile *profile,
queue_delayed_work(devfreq_wq, &devfreq_work,
msecs_to_jiffies(DEVFREQ_INTERVAL));
}
+
+ sysfs_update_group(&dev->kobj, &dev_attr_group);
out:
mutex_unlock(&devfreq_list_lock);

@@ -237,6 +242,8 @@ int devfreq_remove_device(struct device *dev)
return -EINVAL;
}

+ sysfs_remove_group(&dev->kobj, &dev_attr_group);
+
list_del(&devfreq->node);

kfree(devfreq);
@@ -286,6 +293,38 @@ out:
return err;
}

+int _devfreq_tickle_device(struct devfreq *df, unsigned long delay)
+{
+ int err = 0;
+ unsigned long freq;
+ struct opp *opp;
+
+ freq = df->profile->max_freq;
+ opp = opp_find_freq_floor(df->dev, &freq);
+ if (IS_ERR(opp))
+ return PTR_ERR(opp);
+
+ freq = opp_get_freq(opp);
+ if (df->previous_freq != freq) {
+ err = df->profile->target(df->dev, opp);
+ if (!err)
+ df->previous_freq = freq;
+ }
+ if (err) {
+ dev_err(df->dev, "%s: Cannot set frequency.\n", __func__);
+ } else {
+ df->tickle = delay;
+ df->num_tickle++;
+ }
+
+ if (devfreq_wq && !monitoring) {
+ monitoring = true;
+ queue_delayed_work(devfreq_wq, &devfreq_work,
+ msecs_to_jiffies(DEVFREQ_INTERVAL));
+ }
+
+ return err;
+}
/**
* devfreq_tickle_device() - Guarantee maximum operation speed for a while
* instaneously.
@@ -301,43 +340,133 @@ out:
int devfreq_tickle_device(struct device *dev, unsigned long duration_ms)
{
struct devfreq *devfreq;
- struct opp *opp;
- unsigned long freq;
int err = 0;
+ unsigned long delay; /* in num DEVFREQ_INTERVAL */

mutex_lock(&devfreq_list_lock);
devfreq = find_device_devfreq(dev);
- if (!IS_ERR(devfreq)) {
- freq = devfreq->profile->max_freq;
- opp = opp_find_freq_floor(devfreq->dev, &freq);
- freq = opp_get_freq(opp);
- if (devfreq->previous_freq != freq) {
- err = devfreq->profile->target(devfreq->dev, opp);
- if (!err)
- devfreq->previous_freq = freq;
- }
- if (err)
- dev_err(dev, "%s: Cannot set frequency.\n", __func__);
- else
- devfreq->tickle = DIV_ROUND_UP(duration_ms,
- DEVFREQ_INTERVAL);
+ delay = DIV_ROUND_UP(duration_ms, DEVFREQ_INTERVAL);
+
+ if (IS_ERR(devfreq))
+ err = PTR_ERR(devfreq);
+ else
+ err = _devfreq_tickle_device(devfreq, delay);
+
+ mutex_unlock(&devfreq_list_lock);
+
+ return err;
+}
+
+static int num_tickle_all;
+static ssize_t tickle_all(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ int duration;
+ struct devfreq *tmp;
+ unsigned long delay;
+
+ sscanf(buf, "%d", &duration);
+ if (duration < DEVFREQ_INTERVAL)
+ duration = DEVFREQ_INTERVAL;
+
+ if (unlikely(IS_ERR_OR_NULL(dev))) {
+ pr_err("%s: Invalid parameters\n", __func__);
+ return -EINVAL;
}

- if (devfreq_wq && !monitoring) {
- monitoring = true;
- queue_delayed_work(devfreq_wq, &devfreq_work,
- msecs_to_jiffies(DEVFREQ_INTERVAL));
+ delay = DIV_ROUND_UP(duration, DEVFREQ_INTERVAL);
+
+ mutex_lock(&devfreq_list_lock);
+ list_for_each_entry(tmp, &devfreq_list, node) {
+ _devfreq_tickle_device(tmp, delay);
}
mutex_unlock(&devfreq_list_lock);

- if (IS_ERR(devfreq)) {
- dev_err(dev, "%s: Cannot find devfreq.\n", __func__);
- err = PTR_ERR(devfreq);
+ num_tickle_all++;
+ return count;
+}
+
+static ssize_t show_num_tickle_all(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ return sprintf(buf, "%d\n", num_tickle_all);
+}
+
+static ssize_t show_min_interval(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ return sprintf(buf, "%d\n", DEVFREQ_INTERVAL);
+}
+
+static ssize_t show_monitoring(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ return sprintf(buf, "%d\n", monitoring ? 1 : 0);
+}
+
+static DEVICE_ATTR(tickle_all, 0644, show_num_tickle_all, tickle_all);
+static DEVICE_ATTR(min_interval, 0444, show_min_interval, NULL);
+static DEVICE_ATTR(monitoring, 0444, show_monitoring, NULL);
+static struct attribute *devfreq_entries[] = {
+ &dev_attr_tickle_all.attr,
+ &dev_attr_min_interval.attr,
+ &dev_attr_monitoring.attr,
+ NULL,
+};
+static struct attribute_group devfreq_attr_group = {
+ .name = "devfreq",
+ .attrs = devfreq_entries,
+};
+
+static ssize_t tickle(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ int duration;
+ struct devfreq *df;
+ unsigned long delay;
+
+ sscanf(buf, "%d", &duration);
+ if (duration < DEVFREQ_INTERVAL)
+ duration = DEVFREQ_INTERVAL;
+
+ if (unlikely(IS_ERR_OR_NULL(dev))) {
+ pr_err("%s: Invalid parameters\n", __func__);
+ return -EINVAL;
}

- return err;
+ delay = DIV_ROUND_UP(duration, DEVFREQ_INTERVAL);
+
+ mutex_lock(&devfreq_list_lock);
+ df = find_device_devfreq(dev);
+ _devfreq_tickle_device(df, delay);
+ mutex_unlock(&devfreq_list_lock);
+
+ return count;
}

+static ssize_t show_num_tickle(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct devfreq *df;
+
+ df = find_device_devfreq(dev);
+
+ if (!IS_ERR(df))
+ return sprintf(buf, "%d\n", df->num_tickle);
+
+ return PTR_ERR(df);
+}
+
+static DEVICE_ATTR(tickle, 0644, show_num_tickle, tickle);
+static struct attribute *dev_entries[] = {
+ &dev_attr_tickle.attr,
+ NULL,
+};
+static struct attribute_group dev_attr_group = {
+ .name = NULL,
+ .attrs = dev_entries,
+};
+
static int __init devfreq_init(void)
{
mutex_lock(&devfreq_list_lock);
@@ -345,6 +474,20 @@ static int __init devfreq_init(void)
monitoring = false;
devfreq_wq = create_freezable_workqueue("devfreq_wq");
INIT_DELAYED_WORK_DEFERRABLE(&devfreq_work, devfreq_monitor);
+
+ /* Create sysfs */
+#ifdef CONFIG_PM
+ devfreq_kobj = kobject_create_and_add("devfreq", power_kobj);
+ if (!devfreq_kobj) {
+ pr_err("Unable to create DEVFREQ kobject.\n");
+ goto out;
+ }
+ if (sysfs_create_group(devfreq_kobj, &devfreq_attr_group)) {
+ pr_err("Unable to create DEVFREQ sysfs entries.\n");
+ goto out;
+ }
+#endif
+out:
mutex_unlock(&devfreq_list_lock);

devfreq_monitor(&devfreq_work.work);
diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h
index ec41ba6..f6e38ee 100644
--- a/include/linux/devfreq.h
+++ b/include/linux/devfreq.h
@@ -59,6 +59,7 @@ struct devfreq_governor {
* at each executino of devfreq_monitor, tickle is decremented.
* User may tickle a device-devfreq in order to set maximum
* frequency instaneously with some guaranteed duration.
+ * @num_tickle number of tickle calls.
*
* This structure stores the DEVFREQ information for a give device.
*/
@@ -72,6 +73,8 @@ struct devfreq {
unsigned long previous_freq;
unsigned int next_polling;
unsigned int tickle;
+
+ unsigned int num_tickle;
};

#if defined(CONFIG_PM_DEVFREQ)
--
1.7.4.1


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