On Friday, May 27, 2011, MyungJoo Ham wrote:
> 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@xxxxxxxxxxx>
> Signed-off-by: Kyungmin Park <kyungmin.park@xxxxxxxxxxx>
>
> --
> Changed from v2
> - add ABI entries for devfreq sysfs interface
> ---
> Documentation/ABI/testing/sysfs-devices-devfreq | 21 ++++
> Documentation/ABI/testing/sysfs-power | 43 ++++++++
> drivers/base/power/devfreq.c | 133 ++++++++++++++++++++++-
> include/linux/devfreq.h | 3 +
> 4 files changed, 199 insertions(+), 1 deletions(-)
> create mode 100644 Documentation/ABI/testing/sysfs-devices-devfreq
>
> diff --git a/Documentation/ABI/testing/sysfs-devices-devfreq b/Documentation/ABI/testing/sysfs-devices-devfreq
> new file mode 100644
> index 0000000..7f35a64
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-devices-devfreq
> @@ -0,0 +1,21 @@
> +What: /sys/devices/.../devfreq/
> +Date: May 2011
> +Contact: MyungJoo Ham <myungjoo.ham@xxxxxxxxxxx>
> +Description:
> + The /sys/device/.../devfreq directory will contain files
> + that provide interfaces to DEVFREQ for a specific device.
> +
> +What: /sys/devices/.../devfreq/tickle
> +Date: May 2011
> +Contact: MyungJoo Ham <myungjoo.ham@xxxxxxxxxxx>
> +Description:
> + The /sys/devices/.../devfreq/tickle file allows user space
> + to force the corresponding device to operate at its maximum
> + operable frequency instaneously and temporarily. After a
> + designated duration has passed, the operating frequency returns
> + to normal. When a user reads the tickle entry, it returns
> + the number of tickle executions for the device. When a user
> + writes to the tickle entry with the tickle duration in ms,
> + the effect of device tickling is held for the designated
> + duration. Note that the duration is rounded-up by
> + the value DEVFREQ_INTERVAL defined in devfreq.c
> diff --git a/Documentation/ABI/testing/sysfs-power b/Documentation/ABI/testing/sysfs-power
> index b464d12..4d8434b 100644
> --- a/Documentation/ABI/testing/sysfs-power
> +++ b/Documentation/ABI/testing/sysfs-power
> @@ -172,3 +172,46 @@ Description:
>
> Reading from this file will display the current value, which is
> set to 1 MB by default.
> +
> +What: /sys/power/devfreq/
> +Date: May 2011
> +Contact: MyungJoo Ham <myungjoo.ham@xxxxxxxxxxx>
> +Description:
> + The /sys/power/devfreq directory will contain files that will
> + provide a unified interface to the DEVFREQ, a generic DVFS
> + (dynamic voltage and frequency scaling) framework.
> +
> +What: /sys/power/devfreq/tickle_all
> +Date: May 2011
> +Contact: MyungJoo Ham <myungjoo.ham@xxxxxxxxxxx>
> +Description:
> + The /sys/power/devfreq/tickle_all file allows user space to
> + force every device with DEVFREQ to operate at the maximum
> + frequency of the device instaneously and temporarily. After
> + a designated delay has passed, the operating frequency returns
> + to normal. If a user reads the tickle_all entry, it returns
> + the number of tickle_all executions. When writing to the
> + tickle_all entry, the user should supply with the duration of
> + tickle in ms (the "designated delay" mentioned before). Then,
> + the effect of tickle_all will hold for the denoted duration.
> + Note that the duration is rounded by the monitoring period
> + defined by DEVFREQ_INTERVAL in /drivers/base/power/devfreq.c.
> +
> +What: /sys/power/devfreq/min_interval
> +Date: May 2011
> +Contact: MyungJoo Ham <myungjoo.ham@xxxxxxxxxxx>
> +Description:
> + The /sys/power/devfreq/min_interval file shows the monitoring
> + period defined by DEVFREQ_INTERVAL in
> + /drivers/base/power/devfreq.c. The duration of device tickling
> + is rounded-up by DEVFREQ_INTERVAL.
> +
> +What: /sys/power/devfreq/monitoring
> +Date: May 2011
> +Contact: MyungJoo Ham <myungjoo.ham@xxxxxxxxxxx>
> +Description:
> + The /sys/power/devfreq/monitoring file shows whether DEVFREQ
> + is periodically monitoring. Periodic monitoring is activated
> + if there is a device that wants periodic monitoring for DVFS or
> + there is a device that is tickled (and the tickling duration is
> + not yet expired).
> diff --git a/drivers/base/power/devfreq.c b/drivers/base/power/devfreq.c
> index 7648a94..709c138 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.
> @@ -237,6 +240,8 @@ 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);
This appears to modify the attributes of the device, but anything like it is
not mentioned in the documentation. What's up?
> out:
> mutex_unlock(&devfreq_list_lock);
>
> @@ -263,6 +268,8 @@ int devfreq_remove_device(struct device *dev)
> return -EINVAL;
> }
>
> + sysfs_remove_group(&dev->kobj, &dev_attr_group);
> +
> list_del(&devfreq->node);
>
> kfree(devfreq);
> @@ -344,7 +351,7 @@ static int _devfreq_tickle_device(struct devfreq *df, unsigned long delay)
> if (devfreq_wq && !polling) {
> polling = true;
> queue_delayed_work(devfreq_wq, &devfreq_work,
> - msecs_to_jiffies(DEVFREQ_INTERVAL));
> + msecs_to_jiffies(DEVFREQ_INTERVAL));
This change doesn't seem to belong to this patch.
> }
>
> return err;
> @@ -382,6 +389,116 @@ int devfreq_tickle_device(struct device *dev, unsigned long duration_ms)
> 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 = 0;
> + 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__);
Please say "null device" instead of in addition to the above.
> + return -EINVAL;
> + }
> +
> + 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);
> +
> + 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 = NULL,
> + .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__);
Like above.
> + return -EINVAL;
> + }
> +
> + 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 = "devfreq",
> + .attrs = dev_entries,
> +};
> +
> static int __init devfreq_init(void)
> {
> mutex_lock(&devfreq_list_lock);
> @@ -389,6 +506,20 @@ static int __init devfreq_init(void)
> polling = false;
> devfreq_wq = create_freezable_workqueue("devfreq_wq");
> INIT_DELAYED_WORK_DEFERRABLE(&devfreq_work, devfreq_monitor);
> +
> +#ifdef CONFIG_PM
> + /* Create sysfs */
> + devfreq_kobj = kobject_create_and_add("devfreq", power_kobj);
Hmm, so power_kobj is global? It shouldn't be.
Generally, whatever adds attributes to /sys/power should be located in
kernel/power/ .
> + 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 1ec9a40..69334e7 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)
It looks like the above two changes should be moved to a separate patch.
Thanks,
Rafael
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