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Wysocki" Cc: Linux PM , LKML , Alan Stern , Wolfram Sang , Sakari Ailus Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 31 Jul 2020 at 19:03, Rafael J. Wysocki wrote: > > From: Rafael J. Wysocki > > Add kerneldoc comments to multiple PM-runtime helper functions > defined as static inline wrappers around lower-level routines to > provide quick reference decumentation of their behavior. > > Some of them are similar to each other with subtle differences only > and the behavior of some of them may appear as counter-intuitive, so > clarify all that to avoid confusion. > > Signed-off-by: Rafael J. Wysocki Reviewed-by: Ulf Hansson Kind regards Uffe > --- > include/linux/pm_runtime.h | 246 +++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 246 insertions(+) > > Index: linux-pm/include/linux/pm_runtime.h > =================================================================== > --- linux-pm.orig/include/linux/pm_runtime.h > +++ linux-pm/include/linux/pm_runtime.h > @@ -60,58 +60,151 @@ extern void pm_runtime_put_suppliers(str > extern void pm_runtime_new_link(struct device *dev); > extern void pm_runtime_drop_link(struct device *dev); > > +/** > + * pm_runtime_get_if_in_use - Conditionally bump up runtime PM usage counter. > + * @dev: Target device. > + * > + * Increment the runtime PM usage counter of @dev if its runtime PM status is > + * %RPM_ACTIVE and its runtime PM usage counter is greater than 0. > + */ > static inline int pm_runtime_get_if_in_use(struct device *dev) > { > return pm_runtime_get_if_active(dev, false); > } > > +/** > + * pm_suspend_ignore_children - Set runtime PM behavior regarding children. > + * @dev: Target device. > + * @enable: Whether or not to ignore possible dependencies on children. > + * > + * The dependencies of @dev on its children will not be taken into account by > + * the runtime PM framework going forward if @enable is %true, or they will > + * be taken into account otherwise. > + */ > static inline void pm_suspend_ignore_children(struct device *dev, bool enable) > { > dev->power.ignore_children = enable; > } > > +/** > + * pm_runtime_get_noresume - Bump up runtime PM usage counter of a device. > + * @dev: Target device. > + */ > static inline void pm_runtime_get_noresume(struct device *dev) > { > atomic_inc(&dev->power.usage_count); > } > > +/** > + * pm_runtime_put_noidle - Drop runtime PM usage counter of a device. > + * @dev: Target device. > + * > + * Decrement the runtime PM usage counter of @dev unless it is 0 already. > + */ > static inline void pm_runtime_put_noidle(struct device *dev) > { > atomic_add_unless(&dev->power.usage_count, -1, 0); > } > > +/** > + * pm_runtime_suspended - Check whether or not a device is runtime-suspended. > + * @dev: Target device. > + * > + * Return %true if runtime PM is enabled for @dev and its runtime PM status is > + * %RPM_SUSPENDED, or %false otherwise. > + * > + * Note that the return value of this function can only be trusted if it is > + * called under the runtime PM lock of @dev or under conditions in which > + * runtime PM cannot be either disabled or enabled for @dev and its runtime PM > + * status cannot change. > + */ > static inline bool pm_runtime_suspended(struct device *dev) > { > return dev->power.runtime_status == RPM_SUSPENDED > && !dev->power.disable_depth; > } > > +/** > + * pm_runtime_active - Check whether or not a device is runtime-active. > + * @dev: Target device. > + * > + * Return %true if runtime PM is enabled for @dev and its runtime PM status is > + * %RPM_ACTIVE, or %false otherwise. > + * > + * Note that the return value of this function can only be trusted if it is > + * called under the runtime PM lock of @dev or under conditions in which > + * runtime PM cannot be either disabled or enabled for @dev and its runtime PM > + * status cannot change. > + */ > static inline bool pm_runtime_active(struct device *dev) > { > return dev->power.runtime_status == RPM_ACTIVE > || dev->power.disable_depth; > } > > +/** > + * pm_runtime_status_suspended - Check if runtime PM status is "suspended". > + * @dev: Target device. > + * > + * Return %true if the runtime PM status of @dev is %RPM_SUSPENDED, or %false > + * otherwise, regardless of whether or not runtime PM has been enabled for @dev. > + * > + * Note that the return value of this function can only be trusted if it is > + * called under the runtime PM lock of @dev or under conditions in which the > + * runtime PM status of @dev cannot change. > + */ > static inline bool pm_runtime_status_suspended(struct device *dev) > { > return dev->power.runtime_status == RPM_SUSPENDED; > } > > +/** > + * pm_runtime_enabled - Check if runtime PM is enabled. > + * @dev: Target device. > + * > + * Return %true if runtime PM is enabled for @dev or %false otherwise. > + * > + * Note that the return value of this function can only be trusted if it is > + * called under the runtime PM lock of @dev or under conditions in which > + * runtime PM cannot be either disabled or enabled for @dev. > + */ > static inline bool pm_runtime_enabled(struct device *dev) > { > return !dev->power.disable_depth; > } > > +/** > + * pm_runtime_has_no_callbacks - Check if runtime PM callbacks may be present. > + * @dev: Target device. > + * > + * Return %true if @dev is a special device without runtime PM callbacks or > + * %false otherwise. > + */ > static inline bool pm_runtime_has_no_callbacks(struct device *dev) > { > return dev->power.no_callbacks; > } > > +/** > + * pm_runtime_mark_last_busy - Update the last access time of a device. > + * @dev: Target device. > + * > + * Update the last access time of @dev used by the runtime PM autosuspend > + * mechanism to the current time as returned by ktime_get_mono_fast_ns(). > + */ > static inline void pm_runtime_mark_last_busy(struct device *dev) > { > WRITE_ONCE(dev->power.last_busy, ktime_get_mono_fast_ns()); > } > > +/** > + * pm_runtime_is_irq_safe - Check if runtime PM can work in interrupt context. > + * @dev: Target device. > + * > + * Return %true if @dev has been marked as an "IRQ-safe" device (with respect > + * to runtime PM), in which case its runtime PM callabcks can be expected to > + * work correctly when invoked from interrupt handlers. > + */ > static inline bool pm_runtime_is_irq_safe(struct device *dev) > { > return dev->power.irq_safe; > @@ -191,97 +284,250 @@ static inline void pm_runtime_drop_link( > > #endif /* !CONFIG_PM */ > > +/** > + * pm_runtime_idle - Conditionally set up autosuspend of a device or suspend it. > + * @dev: Target device. > + * > + * Invoke the "idle check" callback of @dev and, depending on its return value, > + * set up autosuspend of @dev or suspend it (depending on whether or not > + * autosuspend has been enabled for it). > + */ > static inline int pm_runtime_idle(struct device *dev) > { > return __pm_runtime_idle(dev, 0); > } > > +/** > + * pm_runtime_suspend - Suspend a device synchronously. > + * @dev: Target device. > + */ > static inline int pm_runtime_suspend(struct device *dev) > { > return __pm_runtime_suspend(dev, 0); > } > > +/** > + * pm_runtime_autosuspend - Set up autosuspend of a device or suspend it. > + * @dev: Target device. > + * > + * Set up autosuspend of @dev or suspend it (depending on whether or not > + * autosuspend is enabled for it) without engaging its "idle check" callback. > + */ > static inline int pm_runtime_autosuspend(struct device *dev) > { > return __pm_runtime_suspend(dev, RPM_AUTO); > } > > +/** > + * pm_runtime_resume - Resume a device synchronously. > + * @dev: Target device. > + */ > static inline int pm_runtime_resume(struct device *dev) > { > return __pm_runtime_resume(dev, 0); > } > > +/** > + * pm_request_idle - Queue up "idle check" execution for a device. > + * @dev: Target device. > + * > + * Queue up a work item to run an equivalent of pm_runtime_idle() for @dev > + * asynchronously. > + */ > static inline int pm_request_idle(struct device *dev) > { > return __pm_runtime_idle(dev, RPM_ASYNC); > } > > +/** > + * pm_request_resume - Queue up runtime-resume of a device. > + * @dev: Target device. > + */ > static inline int pm_request_resume(struct device *dev) > { > return __pm_runtime_resume(dev, RPM_ASYNC); > } > > +/** > + * pm_request_autosuspend - Queue up autosuspend of a device. > + * @dev: Target device. > + * > + * Queue up a work item to run an equivalent pm_runtime_autosuspend() for @dev > + * asynchronously. > + */ > static inline int pm_request_autosuspend(struct device *dev) > { > return __pm_runtime_suspend(dev, RPM_ASYNC | RPM_AUTO); > } > > +/** > + * pm_runtime_get - Bump up usage counter and queue up resume of a device. > + * @dev: Target device. > + * > + * Bump up the runtime PM usage counter of @dev and queue up a work item to > + * carry out runtime-resume of it. > + */ > static inline int pm_runtime_get(struct device *dev) > { > return __pm_runtime_resume(dev, RPM_GET_PUT | RPM_ASYNC); > } > > +/** > + * pm_runtime_get_sync - Bump up usage counter of a device and resume it. > + * @dev: Target device. > + * > + * Bump up the runtime PM usage counter of @dev and carry out runtime-resume of > + * it synchronously. > + * > + * The possible return values of this function are the same as for > + * pm_runtime_resume() and the runtime PM usage counter of @dev remains > + * incremented in all cases, even if it returns an error code. > + */ > static inline int pm_runtime_get_sync(struct device *dev) > { > return __pm_runtime_resume(dev, RPM_GET_PUT); > } > > +/** > + * pm_runtime_put - Drop device usage counter and queue up "idle check" if 0. > + * @dev: Target device. > + * > + * Decrement the runtime PM usage counter of @dev and if it turns out to be > + * equal to 0, queue up a work item for @dev like in pm_request_idle(). > + */ > static inline int pm_runtime_put(struct device *dev) > { > return __pm_runtime_idle(dev, RPM_GET_PUT | RPM_ASYNC); > } > > +/** > + * pm_runtime_put_autosuspend - Drop device usage counter and queue autosuspend if 0. > + * @dev: Target device. > + * > + * Decrement the runtime PM usage counter of @dev and if it turns out to be > + * equal to 0, queue up a work item for @dev like in pm_request_autosuspend(). > + */ > static inline int pm_runtime_put_autosuspend(struct device *dev) > { > return __pm_runtime_suspend(dev, > RPM_GET_PUT | RPM_ASYNC | RPM_AUTO); > } > > +/** > + * pm_runtime_put_sync - Drop device usage counter and run "idle check" if 0. > + * @dev: Target device. > + * > + * Decrement the runtime PM usage counter of @dev and if it turns out to be > + * equal to 0, invoke the "idle check" callback of @dev and, depending on its > + * return value, set up autosuspend of @dev or suspend it (depending on whether > + * or not autosuspend has been enabled for it). > + * > + * The possible return values of this function are the same as for > + * pm_runtime_idle() and the runtime PM usage counter of @dev remains > + * decremented in all cases, even if it returns an error code. > + */ > static inline int pm_runtime_put_sync(struct device *dev) > { > return __pm_runtime_idle(dev, RPM_GET_PUT); > } > > +/** > + * pm_runtime_put_sync_suspend - Drop device usage counter and suspend if 0. > + * @dev: Target device. > + * > + * Decrement the runtime PM usage counter of @dev and if it turns out to be > + * equal to 0, carry out runtime-suspend of @dev synchronously. > + * > + * The possible return values of this function are the same as for > + * pm_runtime_suspend() and the runtime PM usage counter of @dev remains > + * decremented in all cases, even if it returns an error code. > + */ > static inline int pm_runtime_put_sync_suspend(struct device *dev) > { > return __pm_runtime_suspend(dev, RPM_GET_PUT); > } > > +/** > + * pm_runtime_put_sync_autosuspend - Drop device usage counter and autosuspend if 0. > + * @dev: Target device. > + * > + * Decrement the runtime PM usage counter of @dev and if it turns out to be > + * equal to 0, set up autosuspend of @dev or suspend it synchronously (depending > + * on whether or not autosuspend has been enabled for it). > + * > + * The possible return values of this function are the same as for > + * pm_runtime_autosuspend() and the runtime PM usage counter of @dev remains > + * decremented in all cases, even if it returns an error code. > + */ > static inline int pm_runtime_put_sync_autosuspend(struct device *dev) > { > return __pm_runtime_suspend(dev, RPM_GET_PUT | RPM_AUTO); > } > > +/** > + * pm_runtime_set_active - Set runtime PM status to "active". > + * @dev: Target device. > + * > + * Set the runtime PM status of @dev to %RPM_ACTIVE and ensure that dependencies > + * of it will be taken into account. > + * > + * It is not valid to call this function for devices with runtime PM enabled. > + */ > static inline int pm_runtime_set_active(struct device *dev) > { > return __pm_runtime_set_status(dev, RPM_ACTIVE); > } > > +/** > + * pm_runtime_set_suspended - Set runtime PM status to "active". > + * @dev: Target device. > + * > + * Set the runtime PM status of @dev to %RPM_SUSPENDED and ensure that > + * dependencies of it will be taken into account. > + * > + * It is not valid to call this function for devices with runtime PM enabled. > + */ > static inline int pm_runtime_set_suspended(struct device *dev) > { > return __pm_runtime_set_status(dev, RPM_SUSPENDED); > } > > +/** > + * pm_runtime_disable - Disable runtime PM for a device. > + * @dev: Target device. > + * > + * Prevent the runtime PM framework from working with @dev (by incrementing its > + * "blocking" counter). > + * > + * For each invocation of this function for @dev there must be a matching > + * pm_runtime_enable() call in order for runtime PM to be enabled for it. > + */ > static inline void pm_runtime_disable(struct device *dev) > { > __pm_runtime_disable(dev, true); > } > > +/** > + * pm_runtime_use_autosuspend - Allow autosuspend to be used for a device. > + * @dev: Target device. > + * > + * Allow the runtime PM autosuspend mechanism to be used for @dev whenever > + * requested (or "autosuspend" will be handled as direct runtime-suspend for > + * it). > + */ > static inline void pm_runtime_use_autosuspend(struct device *dev) > { > __pm_runtime_use_autosuspend(dev, true); > } > > +/** > + * pm_runtime_dont_use_autosuspend - Prevent autosuspend from being used. > + * @dev: Target device. > + * > + * Prevent the runtime PM autosuspend mechanism from being used for @dev which > + * means that "autosuspend" will be handled as direct runtime-suspend for it > + * going forward. > + */ > static inline void pm_runtime_dont_use_autosuspend(struct device *dev) > { > __pm_runtime_use_autosuspend(dev, false); > > >