diff options
Diffstat (limited to 'drivers/devfreq')
| -rw-r--r-- | drivers/devfreq/devfreq.c | 442 | ||||
| -rw-r--r-- | drivers/devfreq/governor.h | 11 | ||||
| -rw-r--r-- | drivers/devfreq/governor_performance.c | 16 | ||||
| -rw-r--r-- | drivers/devfreq/governor_powersave.c | 16 | ||||
| -rw-r--r-- | drivers/devfreq/governor_simpleondemand.c | 24 | ||||
| -rw-r--r-- | drivers/devfreq/governor_userspace.c | 23 |
6 files changed, 268 insertions, 264 deletions
diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c index b146d76f04cf..1aaf1aeb1f1d 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 +117,152 @@ 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); + if (devfreq->profile->polling_ms) + 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); + if (devfreq->stop_polling) { + mutex_unlock(&devfreq->lock); + return; + } + + 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 (!devfreq->stop_polling) + goto out; + + 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; + +out: + 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); + if (!devfreq->stop_polling) + 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 +285,32 @@ 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 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 +325,8 @@ 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 +350,13 @@ 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 +376,41 @@ 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 +418,14 @@ 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 +457,13 @@ 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 +535,6 @@ 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 +542,6 @@ 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 +549,15 @@ 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 +565,7 @@ 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 ea7f13c58ded..bb3aff32d627 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 af75ddd4f158..eea3f9bd7894 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 fec0cdbd2477..2868d98ed3e2 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 a2e3eae79011..3716a659122b 100644 --- a/drivers/devfreq/governor_simpleondemand.c +++ b/drivers/devfreq/governor_simpleondemand.c @@ -12,6 +12,7 @@ #include <linux/errno.h> #include <linux/devfreq.h> #include <linux/math64.h> +#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; } +static 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 0681246fc89d..7067555bd444 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; } +static 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, }; |