> Prepare devfreq core framework to support devices which > can idle. When device idleness is detected perhaps through > runtime-pm, need some mechanism to suspend devfreq load > monitoring and resume back when device is online. Present > code continues monitoring unless device is removed from > devfreq core. > > This patch introduces following design changes, > > - use per device work instead of global work to monitor device > load. This enables suspend/resume of device devfreq and > reduces monitoring code complexity. > - decouple delayed work based load monitoring logic from core > by introducing helpers functions to be used by governors. This > provides flexibility for governors either to use delayed work > based monitoring functions or to implement their own mechanism. > - devfreq core interacts with governors via events to perform > specific actions. These events include start/stop devfreq. > This sets ground for adding suspend/resume events. > > The devfreq apis are not modified and are kept intact. > > Signed-off-by: Rajagopal Venkat Hello, I'll do more through review tomorrow (sorry, I was occuppied by something other than Linux tasks for a while again); however, there are two concerns in this patch. 1. (minor but may bothersome in some rare but not-ignorable cases) Serialization issue between suspend/resume functions; this may happen with some failure or interrupts while entering STR or unexpected usage of the API at drivers. For example, if devfreq_monitor_suspend() and devfreq_montir_resume() are called almost simultaneously, we may execute 1) locked part of suspend, 2) locked part of resume, 3) cancel_delayed_work_sync of suspend. Then, we may have stop_polling = false w/ cancel_delayed_work_sync() in effect. Let's not assume that suspend() and resume() may called almost simultaneously, especially in subsystem core code. 2. What if polling_ms = 0 w/ active governors (such as ondemand)? Users may declare the initial polling_ms = 0 w/ simple-ondemand in order to pause sampling at boot-time and start sampling at run-time some time later. It appears that this patch will start forcibly at boot-time in such a case. > --- > Documentation/ABI/testing/sysfs-class-devfreq | 8 - > drivers/devfreq/devfreq.c | 431 +++++++++++--------------- > drivers/devfreq/governor.h | 11 + > drivers/devfreq/governor_performance.c | 16 +- > drivers/devfreq/governor_powersave.c | 16 +- > drivers/devfreq/governor_simpleondemand.c | 24 ++ > drivers/devfreq/governor_userspace.c | 23 +- > include/linux/devfreq.h | 34 +- > 8 files changed, 267 insertions(+), 296 deletions(-) > > diff --git a/Documentation/ABI/testing/sysfs-class-devfreq b/Documentation/ABI/testing/sysfs-class-devfreq > index 23d78b5..89283b1 100644 > --- a/Documentation/ABI/testing/sysfs-class-devfreq > +++ b/Documentation/ABI/testing/sysfs-class-devfreq > @@ -21,14 +21,6 @@ Description: > The /sys/class/devfreq/.../cur_freq shows the current > frequency of the corresponding devfreq object. > > -What: /sys/class/devfreq/.../central_polling > -Date: September 2011 > -Contact: MyungJoo Ham > -Description: > - The /sys/class/devfreq/.../central_polling shows whether > - the devfreq ojbect is using devfreq-provided central > - polling mechanism or not. > - > What: /sys/class/devfreq/.../polling_interval > Date: September 2011 > Contact: MyungJoo Ham > diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c > index b146d76..8e9b5aa 100644 > --- a/drivers/devfreq/devfreq.c > +++ b/drivers/devfreq/devfreq.c > @@ -30,17 +30,11 @@ > struct class *devfreq_class; > > /* > - * devfreq_work periodically monitors every registered device. > - * The minimum polling interval is one jiffy. The polling interval is > - * determined by the minimum polling period among all polling devfreq > - * devices. The resolution of polling interval is one jiffy. > + * devfreq core provides delayed work based load monitoring helper > + * functions. Governors can use these or can implement their own > + * monitoring mechanism. > */ > -static bool polling; > static struct workqueue_struct *devfreq_wq; > -static struct delayed_work devfreq_work; > - > -/* wait removing if this is to be removed */ > -static struct devfreq *wait_remove_device; > > /* The list of all device-devfreq */ > static LIST_HEAD(devfreq_list); > @@ -72,6 +66,8 @@ static struct devfreq *find_device_devfreq(struct device *dev) > return ERR_PTR(-ENODEV); > } > > +/* Load monitoring helper functions for governors use */ > + > /** > * update_devfreq() - Reevaluate the device and configure frequency. > * @devfreq: the devfreq instance. > @@ -121,6 +117,140 @@ int update_devfreq(struct devfreq *devfreq) > } > > /** > + * devfreq_monitor() - Periodically poll devfreq objects. > + * @work: the work struct used to run devfreq_monitor periodically. > + * > + */ > +static void devfreq_monitor(struct work_struct *work) > +{ > + int err; > + struct devfreq *devfreq = container_of(work, > + struct devfreq, work.work); > + > + mutex_lock(&devfreq->lock); > + err = update_devfreq(devfreq); > + if (err) > + dev_err(&devfreq->dev, "dvfs failed with (%d) error\n", err); > + > + queue_delayed_work(devfreq_wq, &devfreq->work, > + msecs_to_jiffies(devfreq->profile->polling_ms)); > + mutex_unlock(&devfreq->lock); > +} > + > +/** > + * devfreq_monitor_start() - Start load monitoring of devfreq instance > + * @devfreq: the devfreq instance. > + * > + * Helper function for starting devfreq device load monitoing. By > + * default delayed work based monitoring is supported. Function > + * to be called from governor in response to DEVFREQ_GOV_START > + * event when device is added to devfreq framework. > + */ > +void devfreq_monitor_start(struct devfreq *devfreq) > +{ > + INIT_DEFERRABLE_WORK(&devfreq->work, devfreq_monitor); > + queue_delayed_work(devfreq_wq, &devfreq->work, > + msecs_to_jiffies(devfreq->profile->polling_ms)); > +} > + > +/** > + * devfreq_monitor_stop() - Stop load monitoring of a devfreq instance > + * @devfreq: the devfreq instance. > + * > + * Helper function to stop devfreq device load monitoing. Function > + * to be called from governor in response to DEVFREQ_GOV_STOP > + * event when device is removed from devfreq framework. > + */ > +void devfreq_monitor_stop(struct devfreq *devfreq) > +{ > + cancel_delayed_work_sync(&devfreq->work); > +} > + > +/** > + * devfreq_monitor_suspend() - Suspend load monitoring of a devfreq instance > + * @devfreq: the devfreq instance. > + * > + * Helper function to suspend devfreq device load monitoing. Function > + * to be called from governor in response to DEVFREQ_GOV_SUSPEND > + * event or when polling interval is set to zero. > + * > + * Note: Though this function is same as devfreq_monitor_stop(), > + * intentionally kept separate to provide hooks for collecting > + * transition statistics. > + */ > +void devfreq_monitor_suspend(struct devfreq *devfreq) > +{ > + mutex_lock(&devfreq->lock); > + devfreq->stop_polling = true; > + mutex_unlock(&devfreq->lock); > + cancel_delayed_work_sync(&devfreq->work); > +} > + > +/** > + * devfreq_monitor_resume() - Resume load monitoring of a devfreq instance > + * @devfreq: the devfreq instance. > + * > + * Helper function to resume devfreq device load monitoing. Function > + * to be called from governor in response to DEVFREQ_GOV_RESUME > + * event or when polling interval is set to non-zero. > + */ > +void devfreq_monitor_resume(struct devfreq *devfreq) > +{ > + mutex_lock(&devfreq->lock); > + if (!delayed_work_pending(&devfreq->work) && > + devfreq->profile->polling_ms) > + queue_delayed_work(devfreq_wq, &devfreq->work, > + msecs_to_jiffies(devfreq->profile->polling_ms)); > + devfreq->stop_polling = false; > + mutex_unlock(&devfreq->lock); > +} > + > +/** > + * devfreq_interval_update() - Update device devfreq monitoring interval > + * @devfreq: the devfreq instance. > + * @delay: new polling interval to be set. > + * > + * Helper function to set new load monitoring polling interval. Function > + * to be called from governor in response to DEVFREQ_GOV_INTERVAL event. > + */ > +void devfreq_interval_update(struct devfreq *devfreq, unsigned int *delay) > +{ > + unsigned int cur_delay = devfreq->profile->polling_ms; > + unsigned int new_delay = *delay; > + > + mutex_lock(&devfreq->lock); > + devfreq->profile->polling_ms = new_delay; > + > + if (devfreq->stop_polling) > + goto out; > + > + /* if new delay is zero, stop polling */ > + if (!new_delay) { > + mutex_unlock(&devfreq->lock); > + cancel_delayed_work_sync(&devfreq->work); > + return; > + } > + > + /* if current delay is zero, start polling with new delay */ > + if (!cur_delay) { > + queue_delayed_work(devfreq_wq, &devfreq->work, > + msecs_to_jiffies(devfreq->profile->polling_ms)); > + goto out; > + } > + > + /* if current delay is greater than new delay, restart polling */ > + if (cur_delay > new_delay) { > + mutex_unlock(&devfreq->lock); > + cancel_delayed_work_sync(&devfreq->work); > + mutex_lock(&devfreq->lock); > + queue_delayed_work(devfreq_wq, &devfreq->work, > + msecs_to_jiffies(devfreq->profile->polling_ms)); > + } > +out: > + mutex_unlock(&devfreq->lock); > +} > + > +/** > * devfreq_notifier_call() - Notify that the device frequency requirements > * has been changed out of devfreq framework. > * @nb the notifier_block (supposed to be devfreq->nb) > @@ -143,59 +273,33 @@ static int devfreq_notifier_call(struct notifier_block *nb, unsigned long type, > } > > /** > - * _remove_devfreq() - Remove devfreq from the device. > + * _remove_devfreq() - Remove devfreq from the devfreq list and > + release its resources. > * @devfreq: the devfreq struct > * @skip: skip calling device_unregister(). > - * > - * Note that the caller should lock devfreq->lock before calling > - * this. _remove_devfreq() will unlock it and free devfreq > - * internally. devfreq_list_lock should be locked by the caller > - * as well (not relased at return) > - * > - * Lock usage: > - * devfreq->lock: locked before call. > - * unlocked at return (and freed) > - * devfreq_list_lock: locked before call. > - * kept locked at return. > - * if devfreq is centrally polled. > - * > - * Freed memory: > - * devfreq > */ > static void _remove_devfreq(struct devfreq *devfreq, bool skip) > { > - if (!mutex_is_locked(&devfreq->lock)) { > - WARN(true, "devfreq->lock must be locked by the caller.\n"); > - return; > - } > - if (!devfreq->governor->no_central_polling && > - !mutex_is_locked(&devfreq_list_lock)) { > - WARN(true, "devfreq_list_lock must be locked by the caller.\n"); > + mutex_lock(&devfreq_list_lock); > + if (IS_ERR(find_device_devfreq(devfreq->dev.parent))) { > + mutex_unlock(&devfreq_list_lock); > + dev_warn(&devfreq->dev, "releasing devfreq which doesn't exist\n"); > return; > } > + list_del(&devfreq->node); > + mutex_unlock(&devfreq_list_lock); > > - if (devfreq->being_removed) > - return; > - > - devfreq->being_removed = true; > + devfreq->governor->event_handler(devfreq, DEVFREQ_GOV_STOP, NULL); > > if (devfreq->profile->exit) > devfreq->profile->exit(devfreq->dev.parent); > > - if (devfreq->governor->exit) > - devfreq->governor->exit(devfreq); > - > if (!skip && get_device(&devfreq->dev)) { > device_unregister(&devfreq->dev); > put_device(&devfreq->dev); > } > > - if (!devfreq->governor->no_central_polling) > - list_del(&devfreq->node); > - > - mutex_unlock(&devfreq->lock); > mutex_destroy(&devfreq->lock); > - > kfree(devfreq); > } > > @@ -210,130 +314,8 @@ static void _remove_devfreq(struct devfreq *devfreq, bool skip) > static void devfreq_dev_release(struct device *dev) > { > struct devfreq *devfreq = to_devfreq(dev); > - bool central_polling = !devfreq->governor->no_central_polling; > > - /* > - * If devfreq_dev_release() was called by device_unregister() of > - * _remove_devfreq(), we cannot mutex_lock(&devfreq->lock) and > - * being_removed is already set. This also partially checks the case > - * where devfreq_dev_release() is called from a thread other than > - * the one called _remove_devfreq(); however, this case is > - * dealt completely with another following being_removed check. > - * > - * Because being_removed is never being > - * unset, we do not need to worry about race conditions on > - * being_removed. > - */ > - if (devfreq->being_removed) > - return; > - > - if (central_polling) > - mutex_lock(&devfreq_list_lock); > - > - mutex_lock(&devfreq->lock); > - > - /* > - * Check being_removed flag again for the case where > - * devfreq_dev_release() was called in a thread other than the one > - * possibly called _remove_devfreq(). > - */ > - if (devfreq->being_removed) { > - mutex_unlock(&devfreq->lock); > - goto out; > - } > - > - /* devfreq->lock is unlocked and removed in _removed_devfreq() */ > _remove_devfreq(devfreq, true); > - > -out: > - if (central_polling) > - mutex_unlock(&devfreq_list_lock); > -} > - > -/** > - * devfreq_monitor() - Periodically poll devfreq objects. > - * @work: the work struct used to run devfreq_monitor periodically. > - * > - */ > -static void devfreq_monitor(struct work_struct *work) > -{ > - static unsigned long last_polled_at; > - struct devfreq *devfreq, *tmp; > - int error; > - unsigned long jiffies_passed; > - unsigned long next_jiffies = ULONG_MAX, now = jiffies; > - struct device *dev; > - > - /* Initially last_polled_at = 0, polling every device at bootup */ > - jiffies_passed = now - last_polled_at; > - last_polled_at = now; > - if (jiffies_passed == 0) > - jiffies_passed = 1; > - > - mutex_lock(&devfreq_list_lock); > - list_for_each_entry_safe(devfreq, tmp, &devfreq_list, node) { > - mutex_lock(&devfreq->lock); > - dev = devfreq->dev.parent; > - > - /* Do not remove tmp for a while */ > - wait_remove_device = tmp; > - > - if (devfreq->governor->no_central_polling || > - devfreq->next_polling == 0) { > - mutex_unlock(&devfreq->lock); > - continue; > - } > - mutex_unlock(&devfreq_list_lock); > - > - /* > - * Reduce more next_polling if devfreq_wq took an extra > - * delay. (i.e., CPU has been idled.) > - */ > - if (devfreq->next_polling <= jiffies_passed) { > - error = update_devfreq(devfreq); > - > - /* Remove a devfreq with an error. */ > - if (error && error != -EAGAIN) { > - > - dev_err(dev, "Due to update_devfreq error(%d), devfreq(%s) is removed from the device\n", > - error, devfreq->governor->name); > - > - /* > - * Unlock devfreq before locking the list > - * in order to avoid deadlock with > - * find_device_devfreq or others > - */ > - mutex_unlock(&devfreq->lock); > - mutex_lock(&devfreq_list_lock); > - /* Check if devfreq is already removed */ > - if (IS_ERR(find_device_devfreq(dev))) > - continue; > - mutex_lock(&devfreq->lock); > - /* This unlocks devfreq->lock and free it */ > - _remove_devfreq(devfreq, false); > - continue; > - } > - devfreq->next_polling = devfreq->polling_jiffies; > - } else { > - devfreq->next_polling -= jiffies_passed; > - } > - > - if (devfreq->next_polling) > - next_jiffies = (next_jiffies > devfreq->next_polling) ? > - devfreq->next_polling : next_jiffies; > - > - mutex_unlock(&devfreq->lock); > - mutex_lock(&devfreq_list_lock); > - } > - wait_remove_device = NULL; > - mutex_unlock(&devfreq_list_lock); > - > - if (next_jiffies > 0 && next_jiffies < ULONG_MAX) { > - polling = true; > - queue_delayed_work(devfreq_wq, &devfreq_work, next_jiffies); > - } else { > - polling = false; > - } > } > > /** > @@ -357,16 +339,13 @@ struct devfreq *devfreq_add_device(struct device *dev, > return ERR_PTR(-EINVAL); > } > > - > - if (!governor->no_central_polling) { > - mutex_lock(&devfreq_list_lock); > - devfreq = find_device_devfreq(dev); > - mutex_unlock(&devfreq_list_lock); > - if (!IS_ERR(devfreq)) { > - dev_err(dev, "%s: Unable to create devfreq for the device. It already has one.\n", __func__); > - err = -EINVAL; > - goto err_out; > - } > + mutex_lock(&devfreq_list_lock); > + devfreq = find_device_devfreq(dev); > + mutex_unlock(&devfreq_list_lock); > + if (!IS_ERR(devfreq)) { > + dev_err(dev, "%s: Unable to create devfreq for the device. It already has one.\n", __func__); > + err = -EINVAL; > + goto err_out; > } > > devfreq = kzalloc(sizeof(struct devfreq), GFP_KERNEL); > @@ -386,48 +365,41 @@ struct devfreq *devfreq_add_device(struct device *dev, > devfreq->governor = governor; > devfreq->previous_freq = profile->initial_freq; > devfreq->data = data; > - devfreq->next_polling = devfreq->polling_jiffies > - = msecs_to_jiffies(devfreq->profile->polling_ms); > devfreq->nb.notifier_call = devfreq_notifier_call; > > dev_set_name(&devfreq->dev, dev_name(dev)); > err = device_register(&devfreq->dev); > if (err) { > put_device(&devfreq->dev); > + mutex_unlock(&devfreq->lock); > goto err_dev; > } > > - if (governor->init) > - err = governor->init(devfreq); > - if (err) > - goto err_init; > - > mutex_unlock(&devfreq->lock); > > - if (governor->no_central_polling) > - goto out; > - > mutex_lock(&devfreq_list_lock); > - > list_add(&devfreq->node, &devfreq_list); > + mutex_unlock(&devfreq_list_lock); > > - if (devfreq_wq && devfreq->next_polling && !polling) { > - polling = true; > - queue_delayed_work(devfreq_wq, &devfreq_work, > - devfreq->next_polling); > + err = devfreq->governor->event_handler(devfreq, > + DEVFREQ_GOV_START, NULL); > + if (err) { > + dev_err(dev, "%s: Unable to start governor for the device\n", > + __func__); > + goto err_init; > } > - mutex_unlock(&devfreq_list_lock); > -out: > + > return devfreq; > > err_init: > + list_del(&devfreq->node); > device_unregister(&devfreq->dev); > err_dev: > - mutex_unlock(&devfreq->lock); > kfree(devfreq); > err_out: > return ERR_PTR(err); > } > +EXPORT_SYMBOL(devfreq_add_device); > > /** > * devfreq_remove_device() - Remove devfreq feature from a device. > @@ -435,30 +407,14 @@ err_out: > */ > int devfreq_remove_device(struct devfreq *devfreq) > { > - bool central_polling; > - > if (!devfreq) > return -EINVAL; > > - central_polling = !devfreq->governor->no_central_polling; > - > - if (central_polling) { > - mutex_lock(&devfreq_list_lock); > - while (wait_remove_device == devfreq) { > - mutex_unlock(&devfreq_list_lock); > - schedule(); > - mutex_lock(&devfreq_list_lock); > - } > - } > - > - mutex_lock(&devfreq->lock); > - _remove_devfreq(devfreq, false); /* it unlocks devfreq->lock */ > - > - if (central_polling) > - mutex_unlock(&devfreq_list_lock); > + _remove_devfreq(devfreq, false); > > return 0; > } > +EXPORT_SYMBOL(devfreq_remove_device); > > static ssize_t show_governor(struct device *dev, > struct device_attribute *attr, char *buf) > @@ -490,35 +446,13 @@ static ssize_t store_polling_interval(struct device *dev, > if (ret != 1) > goto out; > > - mutex_lock(&df->lock); > - df->profile->polling_ms = value; > - df->next_polling = df->polling_jiffies > - = msecs_to_jiffies(value); > - mutex_unlock(&df->lock); > - > + df->governor->event_handler(df, DEVFREQ_GOV_INTERVAL, &value); > ret = count; > > - if (df->governor->no_central_polling) > - goto out; > - > - mutex_lock(&devfreq_list_lock); > - if (df->next_polling > 0 && !polling) { > - polling = true; > - queue_delayed_work(devfreq_wq, &devfreq_work, > - df->next_polling); > - } > - mutex_unlock(&devfreq_list_lock); > out: > return ret; > } > > -static ssize_t show_central_polling(struct device *dev, > - struct device_attribute *attr, char *buf) > -{ > - return sprintf(buf, "%d\n", > - !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) > { > @@ -590,7 +524,6 @@ static ssize_t show_max_freq(struct device *dev, struct device_attribute *attr, > 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), > @@ -598,23 +531,6 @@ static struct device_attribute devfreq_attrs[] = { > { }, > }; > > -/** > - * devfreq_start_polling() - Initialize data structure for devfreq framework and > - * start polling registered devfreq devices. > - */ > -static int __init devfreq_start_polling(void) > -{ > - mutex_lock(&devfreq_list_lock); > - polling = false; > - devfreq_wq = create_freezable_workqueue("devfreq_wq"); > - INIT_DEFERRABLE_WORK(&devfreq_work, devfreq_monitor); > - mutex_unlock(&devfreq_list_lock); > - > - devfreq_monitor(&devfreq_work.work); > - return 0; > -} > -late_initcall(devfreq_start_polling); > - > static int __init devfreq_init(void) > { > devfreq_class = class_create(THIS_MODULE, "devfreq"); > @@ -622,7 +538,15 @@ static int __init devfreq_init(void) > pr_err("%s: couldn't create class\n", __FILE__); > return PTR_ERR(devfreq_class); > } > + > + devfreq_wq = create_freezable_workqueue("devfreq_wq"); > + if (IS_ERR(devfreq_wq)) { > + class_destroy(devfreq_class); > + pr_err("%s: couldn't create workqueue\n", __FILE__); > + return PTR_ERR(devfreq_wq); > + } > devfreq_class->dev_attrs = devfreq_attrs; > + > return 0; > } > subsys_initcall(devfreq_init); > @@ -630,6 +554,7 @@ subsys_initcall(devfreq_init); > static void __exit devfreq_exit(void) > { > class_destroy(devfreq_class); > + destroy_workqueue(devfreq_wq); > } > module_exit(devfreq_exit); > > diff --git a/drivers/devfreq/governor.h b/drivers/devfreq/governor.h > index ea7f13c..bb3aff3 100644 > --- a/drivers/devfreq/governor.h > +++ b/drivers/devfreq/governor.h > @@ -18,7 +18,18 @@ > > #define to_devfreq(DEV) container_of((DEV), struct devfreq, dev) > > +/* Devfreq events */ > +#define DEVFREQ_GOV_START 0x1 > +#define DEVFREQ_GOV_STOP 0x2 > +#define DEVFREQ_GOV_INTERVAL 0x3 > + > /* Caution: devfreq->lock must be locked before calling update_devfreq */ > extern int update_devfreq(struct devfreq *devfreq); > > +extern void devfreq_monitor_start(struct devfreq *devfreq); > +extern void devfreq_monitor_stop(struct devfreq *devfreq); > +extern void devfreq_monitor_suspend(struct devfreq *devfreq); > +extern void devfreq_monitor_resume(struct devfreq *devfreq); > +extern void devfreq_interval_update(struct devfreq *devfreq, > + unsigned int *delay); > #endif /* _GOVERNOR_H */ > diff --git a/drivers/devfreq/governor_performance.c b/drivers/devfreq/governor_performance.c > index af75ddd..eea3f9b 100644 > --- a/drivers/devfreq/governor_performance.c > +++ b/drivers/devfreq/governor_performance.c > @@ -26,14 +26,22 @@ static int devfreq_performance_func(struct devfreq *df, > return 0; > } > > -static int performance_init(struct devfreq *devfreq) > +static int devfreq_performance_handler(struct devfreq *devfreq, > + unsigned int event, void *data) > { > - return update_devfreq(devfreq); > + int ret = 0; > + > + if (event == DEVFREQ_GOV_START) { > + mutex_lock(&devfreq->lock); > + ret = update_devfreq(devfreq); > + mutex_unlock(&devfreq->lock); > + } > + > + return ret; > } > > const struct devfreq_governor devfreq_performance = { > .name = "performance", > - .init = performance_init, > .get_target_freq = devfreq_performance_func, > - .no_central_polling = true, > + .event_handler = devfreq_performance_handler, > }; > diff --git a/drivers/devfreq/governor_powersave.c b/drivers/devfreq/governor_powersave.c > index fec0cdb..2868d98 100644 > --- a/drivers/devfreq/governor_powersave.c > +++ b/drivers/devfreq/governor_powersave.c > @@ -23,14 +23,22 @@ static int devfreq_powersave_func(struct devfreq *df, > return 0; > } > > -static int powersave_init(struct devfreq *devfreq) > +static int devfreq_powersave_handler(struct devfreq *devfreq, > + unsigned int event, void *data) > { > - return update_devfreq(devfreq); > + int ret = 0; > + > + if (event == DEVFREQ_GOV_START) { > + mutex_lock(&devfreq->lock); > + ret = update_devfreq(devfreq); > + mutex_unlock(&devfreq->lock); > + } > + > + return ret; > } > > const struct devfreq_governor devfreq_powersave = { > .name = "powersave", > - .init = powersave_init, > .get_target_freq = devfreq_powersave_func, > - .no_central_polling = true, > + .event_handler = devfreq_powersave_handler, > }; > diff --git a/drivers/devfreq/governor_simpleondemand.c b/drivers/devfreq/governor_simpleondemand.c > index a2e3eae..cf94218 100644 > --- a/drivers/devfreq/governor_simpleondemand.c > +++ b/drivers/devfreq/governor_simpleondemand.c > @@ -12,6 +12,7 @@ > #include > #include > #include > +#include "governor.h" > > /* Default constants for DevFreq-Simple-Ondemand (DFSO) */ > #define DFSO_UPTHRESHOLD (90) > @@ -88,7 +89,30 @@ static int devfreq_simple_ondemand_func(struct devfreq *df, > return 0; > } > > +int devfreq_simple_ondemand_handler(struct devfreq *devfreq, > + unsigned int event, void *data) > +{ > + switch (event) { > + case DEVFREQ_GOV_START: > + devfreq_monitor_start(devfreq); > + break; > + > + case DEVFREQ_GOV_STOP: > + devfreq_monitor_stop(devfreq); > + break; > + > + case DEVFREQ_GOV_INTERVAL: > + devfreq_interval_update(devfreq, (unsigned int *)data); > + break; > + default: > + break; > + } > + > + return 0; > +} > + > const struct devfreq_governor devfreq_simple_ondemand = { > .name = "simple_ondemand", > .get_target_freq = devfreq_simple_ondemand_func, > + .event_handler = devfreq_simple_ondemand_handler, > }; > diff --git a/drivers/devfreq/governor_userspace.c b/drivers/devfreq/governor_userspace.c > index 0681246..1fddee5 100644 > --- a/drivers/devfreq/governor_userspace.c > +++ b/drivers/devfreq/governor_userspace.c > @@ -116,10 +116,27 @@ static void userspace_exit(struct devfreq *devfreq) > devfreq->data = NULL; > } > > +int devfreq_userspace_handler(struct devfreq *devfreq, > + unsigned int event, void *data) > +{ > + int ret = 0; > + > + switch (event) { > + case DEVFREQ_GOV_START: > + ret = userspace_init(devfreq); > + break; > + case DEVFREQ_GOV_STOP: > + userspace_exit(devfreq); > + break; > + default: > + break; > + } > + > + return ret; > +} > + > const struct devfreq_governor devfreq_userspace = { > .name = "userspace", > .get_target_freq = devfreq_userspace_func, > - .init = userspace_init, > - .exit = userspace_exit, > - .no_central_polling = true, > + .event_handler = devfreq_userspace_handler, > }; > diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h > index 281c72a..2ab70e3 100644 > --- a/include/linux/devfreq.h > +++ b/include/linux/devfreq.h > @@ -91,25 +91,18 @@ struct devfreq_dev_profile { > * status of the device (load = busy_time / total_time). > * If no_central_polling is set, this callback is called > * only with update_devfreq() notified by OPP. > - * @init Called when the devfreq is being attached to a device > - * @exit Called when the devfreq is being removed from a > - * device. Governor should stop any internal routines > - * before return because related data may be > - * freed after exit(). > - * @no_central_polling Do not use devfreq's central polling mechanism. > - * When this is set, devfreq will not call > - * get_target_freq with devfreq_monitor(). However, > - * devfreq will call get_target_freq with > - * devfreq_update() notified by OPP framework. > + * @event_handler Callback for devfreq core framework to notify events > + * to governors. Events include per device governor > + * init and exit, opp changes out of devfreq, suspend > + * and resume of per device devfreq during device idle. > * > * Note that the callbacks are called with devfreq->lock locked by devfreq. > */ > struct devfreq_governor { > const char name[DEVFREQ_NAME_LEN]; > int (*get_target_freq)(struct devfreq *this, unsigned long *freq); > - int (*init)(struct devfreq *this); > - void (*exit)(struct devfreq *this); > - const bool no_central_polling; > + int (*event_handler)(struct devfreq *devfreq, > + unsigned int event, void *data); > }; > > /** > @@ -124,18 +117,13 @@ struct devfreq_governor { > * @nb notifier block used to notify devfreq object that it should > * reevaluate operable frequencies. Devfreq users may use > * devfreq.nb to the corresponding register notifier call chain. > - * @polling_jiffies interval in jiffies. > + * @work delayed work for load monitoring. > * @previous_freq previously configured frequency value. > - * @next_polling the number of remaining jiffies to poll with > - * "devfreq_monitor" executions to reevaluate > - * frequency/voltage of the device. Set by > - * profile's polling_ms interval. > * @data Private data of the governor. The devfreq framework does not > * 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) > + * @stop_polling device load monitoring status. > * > * This structure stores the devfreq information for a give device. > * > @@ -153,17 +141,15 @@ struct devfreq { > struct devfreq_dev_profile *profile; > const struct devfreq_governor *governor; > struct notifier_block nb; > + struct delayed_work work; > > - unsigned long polling_jiffies; > unsigned long previous_freq; > - unsigned int next_polling; > > void *data; /* private data for governors */ > > - bool being_removed; > - > unsigned long min_freq; > unsigned long max_freq; > + bool stop_polling; > }; > > #if defined(CONFIG_PM_DEVFREQ) > -- > 1.7.11.3 > > > > > > > > {.n++%ݶw{.n+{G{ayʇڙ,jfhz_(階ݢj"mG?&~iOzv^m ?I