// SPDX-License-Identifier: GPL-2.0 /* * drivers/base/power/runtime.c - Helper functions for device runtime PM * * Copyright (c) 2009 Rafael J. Wysocki <[email protected]>, Novell Inc. * Copyright (C) 2010 Alan Stern <[email protected]> */ #include <linux/sched/mm.h> #include <linux/ktime.h> #include <linux/hrtimer.h> #include <linux/export.h> #include <linux/pm_runtime.h> #include <linux/pm_wakeirq.h> #include <linux/rculist.h> #include <trace/events/rpm.h> #include "../base.h" #include "power.h" pm_callback_t; static pm_callback_t __rpm_get_callback(struct device *dev, size_t cb_offset) { … } #define RPM_GET_CALLBACK(dev, callback) … static int rpm_resume(struct device *dev, int rpmflags); static int rpm_suspend(struct device *dev, int rpmflags); /** * update_pm_runtime_accounting - Update the time accounting of power states * @dev: Device to update the accounting for * * In order to be able to have time accounting of the various power states * (as used by programs such as PowerTOP to show the effectiveness of runtime * PM), we need to track the time spent in each state. * update_pm_runtime_accounting must be called each time before the * runtime_status field is updated, to account the time in the old state * correctly. */ static void update_pm_runtime_accounting(struct device *dev) { … } static void __update_runtime_status(struct device *dev, enum rpm_status status) { … } static u64 rpm_get_accounted_time(struct device *dev, bool suspended) { … } u64 pm_runtime_active_time(struct device *dev) { … } u64 pm_runtime_suspended_time(struct device *dev) { … } EXPORT_SYMBOL_GPL(…); /** * pm_runtime_deactivate_timer - Deactivate given device's suspend timer. * @dev: Device to handle. */ static void pm_runtime_deactivate_timer(struct device *dev) { … } /** * pm_runtime_cancel_pending - Deactivate suspend timer and cancel requests. * @dev: Device to handle. */ static void pm_runtime_cancel_pending(struct device *dev) { … } /* * pm_runtime_autosuspend_expiration - Get a device's autosuspend-delay expiration time. * @dev: Device to handle. * * Compute the autosuspend-delay expiration time based on the device's * power.last_busy time. If the delay has already expired or is disabled * (negative) or the power.use_autosuspend flag isn't set, return 0. * Otherwise return the expiration time in nanoseconds (adjusted to be nonzero). * * This function may be called either with or without dev->power.lock held. * Either way it can be racy, since power.last_busy may be updated at any time. */ u64 pm_runtime_autosuspend_expiration(struct device *dev) { … } EXPORT_SYMBOL_GPL(…); static int dev_memalloc_noio(struct device *dev, void *data) { … } /* * pm_runtime_set_memalloc_noio - Set a device's memalloc_noio flag. * @dev: Device to handle. * @enable: True for setting the flag and False for clearing the flag. * * Set the flag for all devices in the path from the device to the * root device in the device tree if @enable is true, otherwise clear * the flag for devices in the path whose siblings don't set the flag. * * The function should only be called by block device, or network * device driver for solving the deadlock problem during runtime * resume/suspend: * * If memory allocation with GFP_KERNEL is called inside runtime * resume/suspend callback of any one of its ancestors(or the * block device itself), the deadlock may be triggered inside the * memory allocation since it might not complete until the block * device becomes active and the involed page I/O finishes. The * situation is pointed out first by Alan Stern. Network device * are involved in iSCSI kind of situation. * * The lock of dev_hotplug_mutex is held in the function for handling * hotplug race because pm_runtime_set_memalloc_noio() may be called * in async probe(). * * The function should be called between device_add() and device_del() * on the affected device(block/network device). */ void pm_runtime_set_memalloc_noio(struct device *dev, bool enable) { … } EXPORT_SYMBOL_GPL(…); /** * rpm_check_suspend_allowed - Test whether a device may be suspended. * @dev: Device to test. */ static int rpm_check_suspend_allowed(struct device *dev) { … } static int rpm_get_suppliers(struct device *dev) { … } /** * pm_runtime_release_supplier - Drop references to device link's supplier. * @link: Target device link. * * Drop all runtime PM references associated with @link to its supplier device. */ void pm_runtime_release_supplier(struct device_link *link) { … } static void __rpm_put_suppliers(struct device *dev, bool try_to_suspend) { … } static void rpm_put_suppliers(struct device *dev) { … } static void rpm_suspend_suppliers(struct device *dev) { … } /** * __rpm_callback - Run a given runtime PM callback for a given device. * @cb: Runtime PM callback to run. * @dev: Device to run the callback for. */ static int __rpm_callback(int (*cb)(struct device *), struct device *dev) __releases(&dev->power.lock) __acquires(&dev->power.lock) { … } /** * rpm_callback - Run a given runtime PM callback for a given device. * @cb: Runtime PM callback to run. * @dev: Device to run the callback for. */ static int rpm_callback(int (*cb)(struct device *), struct device *dev) { … } /** * rpm_idle - Notify device bus type if the device can be suspended. * @dev: Device to notify the bus type about. * @rpmflags: Flag bits. * * Check if the device's runtime PM status allows it to be suspended. If * another idle notification has been started earlier, return immediately. If * the RPM_ASYNC flag is set then queue an idle-notification request; otherwise * run the ->runtime_idle() callback directly. If the ->runtime_idle callback * doesn't exist or if it returns 0, call rpm_suspend with the RPM_AUTO flag. * * This function must be called under dev->power.lock with interrupts disabled. */ static int rpm_idle(struct device *dev, int rpmflags) { … } /** * rpm_suspend - Carry out runtime suspend of given device. * @dev: Device to suspend. * @rpmflags: Flag bits. * * Check if the device's runtime PM status allows it to be suspended. * Cancel a pending idle notification, autosuspend or suspend. If * another suspend has been started earlier, either return immediately * or wait for it to finish, depending on the RPM_NOWAIT and RPM_ASYNC * flags. If the RPM_ASYNC flag is set then queue a suspend request; * otherwise run the ->runtime_suspend() callback directly. When * ->runtime_suspend succeeded, if a deferred resume was requested while * the callback was running then carry it out, otherwise send an idle * notification for its parent (if the suspend succeeded and both * ignore_children of parent->power and irq_safe of dev->power are not set). * If ->runtime_suspend failed with -EAGAIN or -EBUSY, and if the RPM_AUTO * flag is set and the next autosuspend-delay expiration time is in the * future, schedule another autosuspend attempt. * * This function must be called under dev->power.lock with interrupts disabled. */ static int rpm_suspend(struct device *dev, int rpmflags) __releases(&dev->power.lock) __acquires(&dev->power.lock) { … } /** * rpm_resume - Carry out runtime resume of given device. * @dev: Device to resume. * @rpmflags: Flag bits. * * Check if the device's runtime PM status allows it to be resumed. Cancel * any scheduled or pending requests. If another resume has been started * earlier, either return immediately or wait for it to finish, depending on the * RPM_NOWAIT and RPM_ASYNC flags. Similarly, if there's a suspend running in * parallel with this function, either tell the other process to resume after * suspending (deferred_resume) or wait for it to finish. If the RPM_ASYNC * flag is set then queue a resume request; otherwise run the * ->runtime_resume() callback directly. Queue an idle notification for the * device if the resume succeeded. * * This function must be called under dev->power.lock with interrupts disabled. */ static int rpm_resume(struct device *dev, int rpmflags) __releases(&dev->power.lock) __acquires(&dev->power.lock) { … } /** * pm_runtime_work - Universal runtime PM work function. * @work: Work structure used for scheduling the execution of this function. * * Use @work to get the device object the work is to be done for, determine what * is to be done and execute the appropriate runtime PM function. */ static void pm_runtime_work(struct work_struct *work) { … } /** * pm_suspend_timer_fn - Timer function for pm_schedule_suspend(). * @timer: hrtimer used by pm_schedule_suspend(). * * Check if the time is right and queue a suspend request. */ static enum hrtimer_restart pm_suspend_timer_fn(struct hrtimer *timer) { … } /** * pm_schedule_suspend - Set up a timer to submit a suspend request in future. * @dev: Device to suspend. * @delay: Time to wait before submitting a suspend request, in milliseconds. */ int pm_schedule_suspend(struct device *dev, unsigned int delay) { … } EXPORT_SYMBOL_GPL(…); static int rpm_drop_usage_count(struct device *dev) { … } /** * __pm_runtime_idle - Entry point for runtime idle operations. * @dev: Device to send idle notification for. * @rpmflags: Flag bits. * * If the RPM_GET_PUT flag is set, decrement the device's usage count and * return immediately if it is larger than zero (if it becomes negative, log a * warning, increment it, and return an error). Then carry out an idle * notification, either synchronous or asynchronous. * * This routine may be called in atomic context if the RPM_ASYNC flag is set, * or if pm_runtime_irq_safe() has been called. */ int __pm_runtime_idle(struct device *dev, int rpmflags) { … } EXPORT_SYMBOL_GPL(…); /** * __pm_runtime_suspend - Entry point for runtime put/suspend operations. * @dev: Device to suspend. * @rpmflags: Flag bits. * * If the RPM_GET_PUT flag is set, decrement the device's usage count and * return immediately if it is larger than zero (if it becomes negative, log a * warning, increment it, and return an error). Then carry out a suspend, * either synchronous or asynchronous. * * This routine may be called in atomic context if the RPM_ASYNC flag is set, * or if pm_runtime_irq_safe() has been called. */ int __pm_runtime_suspend(struct device *dev, int rpmflags) { … } EXPORT_SYMBOL_GPL(…); /** * __pm_runtime_resume - Entry point for runtime resume operations. * @dev: Device to resume. * @rpmflags: Flag bits. * * If the RPM_GET_PUT flag is set, increment the device's usage count. Then * carry out a resume, either synchronous or asynchronous. * * This routine may be called in atomic context if the RPM_ASYNC flag is set, * or if pm_runtime_irq_safe() has been called. */ int __pm_runtime_resume(struct device *dev, int rpmflags) { … } EXPORT_SYMBOL_GPL(…); /** * pm_runtime_get_conditional - Conditionally bump up device usage counter. * @dev: Device to handle. * @ign_usage_count: Whether or not to look at the current usage counter value. * * Return -EINVAL if runtime PM is disabled for @dev. * * Otherwise, if the runtime PM status of @dev is %RPM_ACTIVE and either * @ign_usage_count is %true or the runtime PM usage counter of @dev is not * zero, increment the usage counter of @dev and return 1. Otherwise, return 0 * without changing the usage counter. * * If @ign_usage_count is %true, this function can be used to prevent suspending * the device when its runtime PM status is %RPM_ACTIVE. * * If @ign_usage_count is %false, this function can be used to prevent * suspending the device when both its runtime PM status is %RPM_ACTIVE and its * runtime PM usage counter is not zero. * * The caller is responsible for decrementing the runtime PM usage counter of * @dev after this function has returned a positive value for it. */ static int pm_runtime_get_conditional(struct device *dev, bool ign_usage_count) { … } /** * pm_runtime_get_if_active - Bump up runtime PM usage counter if the device is * in active state * @dev: Target device. * * Increment the runtime PM usage counter of @dev if its runtime PM status is * %RPM_ACTIVE, in which case it returns 1. If the device is in a different * state, 0 is returned. -EINVAL is returned if runtime PM is disabled for the * device, in which case also the usage_count will remain unmodified. */ int pm_runtime_get_if_active(struct device *dev) { … } EXPORT_SYMBOL_GPL(…); /** * 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, in which case * it returns 1. If the device is in a different state or its usage_count is 0, * 0 is returned. -EINVAL is returned if runtime PM is disabled for the device, * in which case also the usage_count will remain unmodified. */ int pm_runtime_get_if_in_use(struct device *dev) { … } EXPORT_SYMBOL_GPL(…); /** * __pm_runtime_set_status - Set runtime PM status of a device. * @dev: Device to handle. * @status: New runtime PM status of the device. * * If runtime PM of the device is disabled or its power.runtime_error field is * different from zero, the status may be changed either to RPM_ACTIVE, or to * RPM_SUSPENDED, as long as that reflects the actual state of the device. * However, if the device has a parent and the parent is not active, and the * parent's power.ignore_children flag is unset, the device's status cannot be * set to RPM_ACTIVE, so -EBUSY is returned in that case. * * If successful, __pm_runtime_set_status() clears the power.runtime_error field * and the device parent's counter of unsuspended children is modified to * reflect the new status. If the new status is RPM_SUSPENDED, an idle * notification request for the parent is submitted. * * If @dev has any suppliers (as reflected by device links to them), and @status * is RPM_ACTIVE, they will be activated upfront and if the activation of one * of them fails, the status of @dev will be changed to RPM_SUSPENDED (instead * of the @status value) and the suppliers will be deacticated on exit. The * error returned by the failing supplier activation will be returned in that * case. */ int __pm_runtime_set_status(struct device *dev, unsigned int status) { … } EXPORT_SYMBOL_GPL(…); /** * __pm_runtime_barrier - Cancel pending requests and wait for completions. * @dev: Device to handle. * * Flush all pending requests for the device from pm_wq and wait for all * runtime PM operations involving the device in progress to complete. * * Should be called under dev->power.lock with interrupts disabled. */ static void __pm_runtime_barrier(struct device *dev) { … } /** * pm_runtime_barrier - Flush pending requests and wait for completions. * @dev: Device to handle. * * Prevent the device from being suspended by incrementing its usage counter and * if there's a pending resume request for the device, wake the device up. * Next, make sure that all pending requests for the device have been flushed * from pm_wq and wait for all runtime PM operations involving the device in * progress to complete. * * Return value: * 1, if there was a resume request pending and the device had to be woken up, * 0, otherwise */ int pm_runtime_barrier(struct device *dev) { … } EXPORT_SYMBOL_GPL(…); /** * __pm_runtime_disable - Disable runtime PM of a device. * @dev: Device to handle. * @check_resume: If set, check if there's a resume request for the device. * * Increment power.disable_depth for the device and if it was zero previously, * cancel all pending runtime PM requests for the device and wait for all * operations in progress to complete. The device can be either active or * suspended after its runtime PM has been disabled. * * If @check_resume is set and there's a resume request pending when * __pm_runtime_disable() is called and power.disable_depth is zero, the * function will wake up the device before disabling its runtime PM. */ void __pm_runtime_disable(struct device *dev, bool check_resume) { … } EXPORT_SYMBOL_GPL(…); /** * pm_runtime_enable - Enable runtime PM of a device. * @dev: Device to handle. */ void pm_runtime_enable(struct device *dev) { … } EXPORT_SYMBOL_GPL(…); static void pm_runtime_disable_action(void *data) { … } /** * devm_pm_runtime_enable - devres-enabled version of pm_runtime_enable. * * NOTE: this will also handle calling pm_runtime_dont_use_autosuspend() for * you at driver exit time if needed. * * @dev: Device to handle. */ int devm_pm_runtime_enable(struct device *dev) { … } EXPORT_SYMBOL_GPL(…); /** * pm_runtime_forbid - Block runtime PM of a device. * @dev: Device to handle. * * Increase the device's usage count and clear its power.runtime_auto flag, * so that it cannot be suspended at run time until pm_runtime_allow() is called * for it. */ void pm_runtime_forbid(struct device *dev) { … } EXPORT_SYMBOL_GPL(…); /** * pm_runtime_allow - Unblock runtime PM of a device. * @dev: Device to handle. * * Decrease the device's usage count and set its power.runtime_auto flag. */ void pm_runtime_allow(struct device *dev) { … } EXPORT_SYMBOL_GPL(…); /** * pm_runtime_no_callbacks - Ignore runtime PM callbacks for a device. * @dev: Device to handle. * * Set the power.no_callbacks flag, which tells the PM core that this * device is power-managed through its parent and has no runtime PM * callbacks of its own. The runtime sysfs attributes will be removed. */ void pm_runtime_no_callbacks(struct device *dev) { … } EXPORT_SYMBOL_GPL(…); /** * pm_runtime_irq_safe - Leave interrupts disabled during callbacks. * @dev: Device to handle * * Set the power.irq_safe flag, which tells the PM core that the * ->runtime_suspend() and ->runtime_resume() callbacks for this device should * always be invoked with the spinlock held and interrupts disabled. It also * causes the parent's usage counter to be permanently incremented, preventing * the parent from runtime suspending -- otherwise an irq-safe child might have * to wait for a non-irq-safe parent. */ void pm_runtime_irq_safe(struct device *dev) { … } EXPORT_SYMBOL_GPL(…); /** * update_autosuspend - Handle a change to a device's autosuspend settings. * @dev: Device to handle. * @old_delay: The former autosuspend_delay value. * @old_use: The former use_autosuspend value. * * Prevent runtime suspend if the new delay is negative and use_autosuspend is * set; otherwise allow it. Send an idle notification if suspends are allowed. * * This function must be called under dev->power.lock with interrupts disabled. */ static void update_autosuspend(struct device *dev, int old_delay, int old_use) { … } /** * pm_runtime_set_autosuspend_delay - Set a device's autosuspend_delay value. * @dev: Device to handle. * @delay: Value of the new delay in milliseconds. * * Set the device's power.autosuspend_delay value. If it changes to negative * and the power.use_autosuspend flag is set, prevent runtime suspends. If it * changes the other way, allow runtime suspends. */ void pm_runtime_set_autosuspend_delay(struct device *dev, int delay) { … } EXPORT_SYMBOL_GPL(…); /** * __pm_runtime_use_autosuspend - Set a device's use_autosuspend flag. * @dev: Device to handle. * @use: New value for use_autosuspend. * * Set the device's power.use_autosuspend flag, and allow or prevent runtime * suspends as needed. */ void __pm_runtime_use_autosuspend(struct device *dev, bool use) { … } EXPORT_SYMBOL_GPL(…); /** * pm_runtime_init - Initialize runtime PM fields in given device object. * @dev: Device object to initialize. */ void pm_runtime_init(struct device *dev) { … } /** * pm_runtime_reinit - Re-initialize runtime PM fields in given device object. * @dev: Device object to re-initialize. */ void pm_runtime_reinit(struct device *dev) { … } /** * pm_runtime_remove - Prepare for removing a device from device hierarchy. * @dev: Device object being removed from device hierarchy. */ void pm_runtime_remove(struct device *dev) { … } /** * pm_runtime_get_suppliers - Resume and reference-count supplier devices. * @dev: Consumer device. */ void pm_runtime_get_suppliers(struct device *dev) { … } /** * pm_runtime_put_suppliers - Drop references to supplier devices. * @dev: Consumer device. */ void pm_runtime_put_suppliers(struct device *dev) { … } void pm_runtime_new_link(struct device *dev) { … } static void pm_runtime_drop_link_count(struct device *dev) { … } /** * pm_runtime_drop_link - Prepare for device link removal. * @link: Device link going away. * * Drop the link count of the consumer end of @link and decrement the supplier * device's runtime PM usage counter as many times as needed to drop all of the * PM runtime reference to it from the consumer. */ void pm_runtime_drop_link(struct device_link *link) { … } static bool pm_runtime_need_not_resume(struct device *dev) { … } /** * pm_runtime_force_suspend - Force a device into suspend state if needed. * @dev: Device to suspend. * * Disable runtime PM so we safely can check the device's runtime PM status and * if it is active, invoke its ->runtime_suspend callback to suspend it and * change its runtime PM status field to RPM_SUSPENDED. Also, if the device's * usage and children counters don't indicate that the device was in use before * the system-wide transition under way, decrement its parent's children counter * (if there is a parent). Keep runtime PM disabled to preserve the state * unless we encounter errors. * * Typically this function may be invoked from a system suspend callback to make * sure the device is put into low power state and it should only be used during * system-wide PM transitions to sleep states. It assumes that the analogous * pm_runtime_force_resume() will be used to resume the device. * * Do not use with DPM_FLAG_SMART_SUSPEND as this can lead to an inconsistent * state where this function has called the ->runtime_suspend callback but the * PM core marks the driver as runtime active. */ int pm_runtime_force_suspend(struct device *dev) { … } EXPORT_SYMBOL_GPL(…); /** * pm_runtime_force_resume - Force a device into resume state if needed. * @dev: Device to resume. * * Prior invoking this function we expect the user to have brought the device * into low power state by a call to pm_runtime_force_suspend(). Here we reverse * those actions and bring the device into full power, if it is expected to be * used on system resume. In the other case, we defer the resume to be managed * via runtime PM. * * Typically this function may be invoked from a system resume callback. */ int pm_runtime_force_resume(struct device *dev) { … } EXPORT_SYMBOL_GPL(…);
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