diff options
Diffstat (limited to 'drivers/base/power/runtime.c')
| -rw-r--r-- | drivers/base/power/runtime.c | 1721 |
1 files changed, 1721 insertions, 0 deletions
diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c new file mode 100644 index 000000000..eaae4adf9 --- /dev/null +++ b/drivers/base/power/runtime.c @@ -0,0 +1,1721 @@ +/* + * drivers/base/power/runtime.c - Helper functions for device runtime PM + * + * Copyright (c) 2009 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc. + * Copyright (C) 2010 Alan Stern <stern@rowland.harvard.edu> + * + * This file is released under the GPLv2. + */ + +#include <linux/sched/mm.h> +#include <linux/export.h> +#include <linux/pm_runtime.h> +#include <linux/pm_wakeirq.h> +#include <trace/events/rpm.h> + +#include "../base.h" +#include "power.h" + +typedef int (*pm_callback_t)(struct device *); + +static pm_callback_t __rpm_get_callback(struct device *dev, size_t cb_offset) +{ + pm_callback_t cb; + const struct dev_pm_ops *ops; + + if (dev->pm_domain) + ops = &dev->pm_domain->ops; + else if (dev->type && dev->type->pm) + ops = dev->type->pm; + else if (dev->class && dev->class->pm) + ops = dev->class->pm; + else if (dev->bus && dev->bus->pm) + ops = dev->bus->pm; + else + ops = NULL; + + if (ops) + cb = *(pm_callback_t *)((void *)ops + cb_offset); + else + cb = NULL; + + if (!cb && dev->driver && dev->driver->pm) + cb = *(pm_callback_t *)((void *)dev->driver->pm + cb_offset); + + return cb; +} + +#define RPM_GET_CALLBACK(dev, callback) \ + __rpm_get_callback(dev, offsetof(struct dev_pm_ops, 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. + */ +void update_pm_runtime_accounting(struct device *dev) +{ + unsigned long now = jiffies; + unsigned long delta; + + delta = now - dev->power.accounting_timestamp; + + dev->power.accounting_timestamp = now; + + if (dev->power.disable_depth > 0) + return; + + if (dev->power.runtime_status == RPM_SUSPENDED) + dev->power.suspended_jiffies += delta; + else + dev->power.active_jiffies += delta; +} + +static void __update_runtime_status(struct device *dev, enum rpm_status status) +{ + update_pm_runtime_accounting(dev); + dev->power.runtime_status = status; +} + +/** + * pm_runtime_deactivate_timer - Deactivate given device's suspend timer. + * @dev: Device to handle. + */ +static void pm_runtime_deactivate_timer(struct device *dev) +{ + if (dev->power.timer_expires > 0) { + del_timer(&dev->power.suspend_timer); + dev->power.timer_expires = 0; + } +} + +/** + * 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_deactivate_timer(dev); + /* + * In case there's a request pending, make sure its work function will + * return without doing anything. + */ + dev->power.request = RPM_REQ_NONE; +} + +/* + * 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 jiffies (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. + */ +unsigned long pm_runtime_autosuspend_expiration(struct device *dev) +{ + int autosuspend_delay; + long elapsed; + unsigned long last_busy; + unsigned long expires = 0; + + if (!dev->power.use_autosuspend) + goto out; + + autosuspend_delay = READ_ONCE(dev->power.autosuspend_delay); + if (autosuspend_delay < 0) + goto out; + + last_busy = READ_ONCE(dev->power.last_busy); + elapsed = jiffies - last_busy; + if (elapsed < 0) + goto out; /* jiffies has wrapped around. */ + + /* + * If the autosuspend_delay is >= 1 second, align the timer by rounding + * up to the nearest second. + */ + expires = last_busy + msecs_to_jiffies(autosuspend_delay); + if (autosuspend_delay >= 1000) + expires = round_jiffies(expires); + expires += !expires; + if (elapsed >= expires - last_busy) + expires = 0; /* Already expired. */ + + out: + return expires; +} +EXPORT_SYMBOL_GPL(pm_runtime_autosuspend_expiration); + +static int dev_memalloc_noio(struct device *dev, void *data) +{ + return dev->power.memalloc_noio; +} + +/* + * 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) +{ + static DEFINE_MUTEX(dev_hotplug_mutex); + + mutex_lock(&dev_hotplug_mutex); + for (;;) { + bool enabled; + + /* hold power lock since bitfield is not SMP-safe. */ + spin_lock_irq(&dev->power.lock); + enabled = dev->power.memalloc_noio; + dev->power.memalloc_noio = enable; + spin_unlock_irq(&dev->power.lock); + + /* + * not need to enable ancestors any more if the device + * has been enabled. + */ + if (enabled && enable) + break; + + dev = dev->parent; + + /* + * clear flag of the parent device only if all the + * children don't set the flag because ancestor's + * flag was set by any one of the descendants. + */ + if (!dev || (!enable && + device_for_each_child(dev, NULL, + dev_memalloc_noio))) + break; + } + mutex_unlock(&dev_hotplug_mutex); +} +EXPORT_SYMBOL_GPL(pm_runtime_set_memalloc_noio); + +/** + * rpm_check_suspend_allowed - Test whether a device may be suspended. + * @dev: Device to test. + */ +static int rpm_check_suspend_allowed(struct device *dev) +{ + int retval = 0; + + if (dev->power.runtime_error) + retval = -EINVAL; + else if (dev->power.disable_depth > 0) + retval = -EACCES; + else if (atomic_read(&dev->power.usage_count) > 0) + retval = -EAGAIN; + else if (!dev->power.ignore_children && + atomic_read(&dev->power.child_count)) + retval = -EBUSY; + + /* Pending resume requests take precedence over suspends. */ + else if ((dev->power.deferred_resume + && dev->power.runtime_status == RPM_SUSPENDING) + || (dev->power.request_pending + && dev->power.request == RPM_REQ_RESUME)) + retval = -EAGAIN; + else if (__dev_pm_qos_read_value(dev) == 0) + retval = -EPERM; + else if (dev->power.runtime_status == RPM_SUSPENDED) + retval = 1; + + return retval; +} + +static int rpm_get_suppliers(struct device *dev) +{ + struct device_link *link; + + list_for_each_entry_rcu(link, &dev->links.suppliers, c_node) { + int retval; + + if (!(link->flags & DL_FLAG_PM_RUNTIME) || + READ_ONCE(link->status) == DL_STATE_SUPPLIER_UNBIND) + continue; + + retval = pm_runtime_get_sync(link->supplier); + /* Ignore suppliers with disabled runtime PM. */ + if (retval < 0 && retval != -EACCES) { + pm_runtime_put_noidle(link->supplier); + return retval; + } + refcount_inc(&link->rpm_active); + } + return 0; +} + +static void rpm_put_suppliers(struct device *dev) +{ + struct device_link *link; + + list_for_each_entry_rcu(link, &dev->links.suppliers, c_node) { + if (READ_ONCE(link->status) == DL_STATE_SUPPLIER_UNBIND) + continue; + + while (refcount_dec_not_one(&link->rpm_active)) + pm_runtime_put(link->supplier); + } +} + +/** + * __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) +{ + int retval, idx; + bool use_links = dev->power.links_count > 0; + + if (dev->power.irq_safe) { + spin_unlock(&dev->power.lock); + } else { + spin_unlock_irq(&dev->power.lock); + + /* + * Resume suppliers if necessary. + * + * The device's runtime PM status cannot change until this + * routine returns, so it is safe to read the status outside of + * the lock. + */ + if (use_links && dev->power.runtime_status == RPM_RESUMING) { + idx = device_links_read_lock(); + + retval = rpm_get_suppliers(dev); + if (retval) + goto fail; + + device_links_read_unlock(idx); + } + } + + retval = cb(dev); + + if (dev->power.irq_safe) { + spin_lock(&dev->power.lock); + } else { + /* + * If the device is suspending and the callback has returned + * success, drop the usage counters of the suppliers that have + * been reference counted on its resume. + * + * Do that if resume fails too. + */ + if (use_links + && ((dev->power.runtime_status == RPM_SUSPENDING && !retval) + || (dev->power.runtime_status == RPM_RESUMING && retval))) { + idx = device_links_read_lock(); + + fail: + rpm_put_suppliers(dev); + + device_links_read_unlock(idx); + } + + spin_lock_irq(&dev->power.lock); + } + + return retval; +} + +/** + * 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) +{ + int (*callback)(struct device *); + int retval; + + trace_rpm_idle_rcuidle(dev, rpmflags); + retval = rpm_check_suspend_allowed(dev); + if (retval < 0) + ; /* Conditions are wrong. */ + + /* Idle notifications are allowed only in the RPM_ACTIVE state. */ + else if (dev->power.runtime_status != RPM_ACTIVE) + retval = -EAGAIN; + + /* + * Any pending request other than an idle notification takes + * precedence over us, except that the timer may be running. + */ + else if (dev->power.request_pending && + dev->power.request > RPM_REQ_IDLE) + retval = -EAGAIN; + + /* Act as though RPM_NOWAIT is always set. */ + else if (dev->power.idle_notification) + retval = -EINPROGRESS; + if (retval) + goto out; + + /* Pending requests need to be canceled. */ + dev->power.request = RPM_REQ_NONE; + + if (dev->power.no_callbacks) + goto out; + + /* Carry out an asynchronous or a synchronous idle notification. */ + if (rpmflags & RPM_ASYNC) { + dev->power.request = RPM_REQ_IDLE; + if (!dev->power.request_pending) { + dev->power.request_pending = true; + queue_work(pm_wq, &dev->power.work); + } + trace_rpm_return_int_rcuidle(dev, _THIS_IP_, 0); + return 0; + } + + dev->power.idle_notification = true; + + callback = RPM_GET_CALLBACK(dev, runtime_idle); + + if (callback) + retval = __rpm_callback(callback, dev); + + dev->power.idle_notification = false; + wake_up_all(&dev->power.wait_queue); + + out: + trace_rpm_return_int_rcuidle(dev, _THIS_IP_, retval); + return retval ? retval : rpm_suspend(dev, rpmflags | RPM_AUTO); +} + +/** + * 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) +{ + int retval; + + if (!cb) + return -ENOSYS; + + if (dev->power.memalloc_noio) { + unsigned int noio_flag; + + /* + * Deadlock might be caused if memory allocation with + * GFP_KERNEL happens inside runtime_suspend and + * runtime_resume callbacks of one block device's + * ancestor or the block device itself. Network + * device might be thought as part of iSCSI block + * device, so network device and its ancestor should + * be marked as memalloc_noio too. + */ + noio_flag = memalloc_noio_save(); + retval = __rpm_callback(cb, dev); + memalloc_noio_restore(noio_flag); + } else { + retval = __rpm_callback(cb, dev); + } + + dev->power.runtime_error = retval; + return retval != -EACCES ? retval : -EIO; +} + +/** + * 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) +{ + int (*callback)(struct device *); + struct device *parent = NULL; + int retval; + + trace_rpm_suspend_rcuidle(dev, rpmflags); + + repeat: + retval = rpm_check_suspend_allowed(dev); + + if (retval < 0) + ; /* Conditions are wrong. */ + + /* Synchronous suspends are not allowed in the RPM_RESUMING state. */ + else if (dev->power.runtime_status == RPM_RESUMING && + !(rpmflags & RPM_ASYNC)) + retval = -EAGAIN; + if (retval) + goto out; + + /* If the autosuspend_delay time hasn't expired yet, reschedule. */ + if ((rpmflags & RPM_AUTO) + && dev->power.runtime_status != RPM_SUSPENDING) { + unsigned long expires = pm_runtime_autosuspend_expiration(dev); + + if (expires != 0) { + /* Pending requests need to be canceled. */ + dev->power.request = RPM_REQ_NONE; + + /* + * Optimization: If the timer is already running and is + * set to expire at or before the autosuspend delay, + * avoid the overhead of resetting it. Just let it + * expire; pm_suspend_timer_fn() will take care of the + * rest. + */ + if (!(dev->power.timer_expires && time_before_eq( + dev->power.timer_expires, expires))) { + dev->power.timer_expires = expires; + mod_timer(&dev->power.suspend_timer, expires); + } + dev->power.timer_autosuspends = 1; + goto out; + } + } + + /* Other scheduled or pending requests need to be canceled. */ + pm_runtime_cancel_pending(dev); + + if (dev->power.runtime_status == RPM_SUSPENDING) { + DEFINE_WAIT(wait); + + if (rpmflags & (RPM_ASYNC | RPM_NOWAIT)) { + retval = -EINPROGRESS; + goto out; + } + + if (dev->power.irq_safe) { + spin_unlock(&dev->power.lock); + + cpu_relax(); + + spin_lock(&dev->power.lock); + goto repeat; + } + + /* Wait for the other suspend running in parallel with us. */ + for (;;) { + prepare_to_wait(&dev->power.wait_queue, &wait, + TASK_UNINTERRUPTIBLE); + if (dev->power.runtime_status != RPM_SUSPENDING) + break; + + spin_unlock_irq(&dev->power.lock); + + schedule(); + + spin_lock_irq(&dev->power.lock); + } + finish_wait(&dev->power.wait_queue, &wait); + goto repeat; + } + + if (dev->power.no_callbacks) + goto no_callback; /* Assume success. */ + + /* Carry out an asynchronous or a synchronous suspend. */ + if (rpmflags & RPM_ASYNC) { + dev->power.request = (rpmflags & RPM_AUTO) ? + RPM_REQ_AUTOSUSPEND : RPM_REQ_SUSPEND; + if (!dev->power.request_pending) { + dev->power.request_pending = true; + queue_work(pm_wq, &dev->power.work); + } + goto out; + } + + __update_runtime_status(dev, RPM_SUSPENDING); + + callback = RPM_GET_CALLBACK(dev, runtime_suspend); + + dev_pm_enable_wake_irq_check(dev, true); + retval = rpm_callback(callback, dev); + if (retval) + goto fail; + + no_callback: + __update_runtime_status(dev, RPM_SUSPENDED); + pm_runtime_deactivate_timer(dev); + + if (dev->parent) { + parent = dev->parent; + atomic_add_unless(&parent->power.child_count, -1, 0); + } + wake_up_all(&dev->power.wait_queue); + + if (dev->power.deferred_resume) { + dev->power.deferred_resume = false; + rpm_resume(dev, 0); + retval = -EAGAIN; + goto out; + } + + /* Maybe the parent is now able to suspend. */ + if (parent && !parent->power.ignore_children && !dev->power.irq_safe) { + spin_unlock(&dev->power.lock); + + spin_lock(&parent->power.lock); + rpm_idle(parent, RPM_ASYNC); + spin_unlock(&parent->power.lock); + + spin_lock(&dev->power.lock); + } + + out: + trace_rpm_return_int_rcuidle(dev, _THIS_IP_, retval); + + return retval; + + fail: + dev_pm_disable_wake_irq_check(dev); + __update_runtime_status(dev, RPM_ACTIVE); + dev->power.deferred_resume = false; + wake_up_all(&dev->power.wait_queue); + + if (retval == -EAGAIN || retval == -EBUSY) { + dev->power.runtime_error = 0; + + /* + * If the callback routine failed an autosuspend, and + * if the last_busy time has been updated so that there + * is a new autosuspend expiration time, automatically + * reschedule another autosuspend. + */ + if ((rpmflags & RPM_AUTO) && + pm_runtime_autosuspend_expiration(dev) != 0) + goto repeat; + } else { + pm_runtime_cancel_pending(dev); + } + goto out; +} + +/** + * 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) +{ + int (*callback)(struct device *); + struct device *parent = NULL; + int retval = 0; + + trace_rpm_resume_rcuidle(dev, rpmflags); + + repeat: + if (dev->power.runtime_error) + retval = -EINVAL; + else if (dev->power.disable_depth == 1 && dev->power.is_suspended + && dev->power.runtime_status == RPM_ACTIVE) + retval = 1; + else if (dev->power.disable_depth > 0) + retval = -EACCES; + if (retval) + goto out; + + /* + * Other scheduled or pending requests need to be canceled. Small + * optimization: If an autosuspend timer is running, leave it running + * rather than cancelling it now only to restart it again in the near + * future. + */ + dev->power.request = RPM_REQ_NONE; + if (!dev->power.timer_autosuspends) + pm_runtime_deactivate_timer(dev); + + if (dev->power.runtime_status == RPM_ACTIVE) { + retval = 1; + goto out; + } + + if (dev->power.runtime_status == RPM_RESUMING + || dev->power.runtime_status == RPM_SUSPENDING) { + DEFINE_WAIT(wait); + + if (rpmflags & (RPM_ASYNC | RPM_NOWAIT)) { + if (dev->power.runtime_status == RPM_SUSPENDING) + dev->power.deferred_resume = true; + else + retval = -EINPROGRESS; + goto out; + } + + if (dev->power.irq_safe) { + spin_unlock(&dev->power.lock); + + cpu_relax(); + + spin_lock(&dev->power.lock); + goto repeat; + } + + /* Wait for the operation carried out in parallel with us. */ + for (;;) { + prepare_to_wait(&dev->power.wait_queue, &wait, + TASK_UNINTERRUPTIBLE); + if (dev->power.runtime_status != RPM_RESUMING + && dev->power.runtime_status != RPM_SUSPENDING) + break; + + spin_unlock_irq(&dev->power.lock); + + schedule(); + + spin_lock_irq(&dev->power.lock); + } + finish_wait(&dev->power.wait_queue, &wait); + goto repeat; + } + + /* + * See if we can skip waking up the parent. This is safe only if + * power.no_callbacks is set, because otherwise we don't know whether + * the resume will actually succeed. + */ + if (dev->power.no_callbacks && !parent && dev->parent) { + spin_lock_nested(&dev->parent->power.lock, SINGLE_DEPTH_NESTING); + if (dev->parent->power.disable_depth > 0 + || dev->parent->power.ignore_children + || dev->parent->power.runtime_status == RPM_ACTIVE) { + atomic_inc(&dev->parent->power.child_count); + spin_unlock(&dev->parent->power.lock); + retval = 1; + goto no_callback; /* Assume success. */ + } + spin_unlock(&dev->parent->power.lock); + } + + /* Carry out an asynchronous or a synchronous resume. */ + if (rpmflags & RPM_ASYNC) { + dev->power.request = RPM_REQ_RESUME; + if (!dev->power.request_pending) { + dev->power.request_pending = true; + queue_work(pm_wq, &dev->power.work); + } + retval = 0; + goto out; + } + + if (!parent && dev->parent) { + /* + * Increment the parent's usage counter and resume it if + * necessary. Not needed if dev is irq-safe; then the + * parent is permanently resumed. + */ + parent = dev->parent; + if (dev->power.irq_safe) + goto skip_parent; + spin_unlock(&dev->power.lock); + + pm_runtime_get_noresume(parent); + + spin_lock(&parent->power.lock); + /* + * Resume the parent if it has runtime PM enabled and not been + * set to ignore its children. + */ + if (!parent->power.disable_depth + && !parent->power.ignore_children) { + rpm_resume(parent, 0); + if (parent->power.runtime_status != RPM_ACTIVE) + retval = -EBUSY; + } + spin_unlock(&parent->power.lock); + + spin_lock(&dev->power.lock); + if (retval) + goto out; + goto repeat; + } + skip_parent: + + if (dev->power.no_callbacks) + goto no_callback; /* Assume success. */ + + __update_runtime_status(dev, RPM_RESUMING); + + callback = RPM_GET_CALLBACK(dev, runtime_resume); + + dev_pm_disable_wake_irq_check(dev); + retval = rpm_callback(callback, dev); + if (retval) { + __update_runtime_status(dev, RPM_SUSPENDED); + pm_runtime_cancel_pending(dev); + dev_pm_enable_wake_irq_check(dev, false); + } else { + no_callback: + __update_runtime_status(dev, RPM_ACTIVE); + pm_runtime_mark_last_busy(dev); + if (parent) + atomic_inc(&parent->power.child_count); + } + wake_up_all(&dev->power.wait_queue); + + if (retval >= 0) + rpm_idle(dev, RPM_ASYNC); + + out: + if (parent && !dev->power.irq_safe) { + spin_unlock_irq(&dev->power.lock); + + pm_runtime_put(parent); + + spin_lock_irq(&dev->power.lock); + } + + trace_rpm_return_int_rcuidle(dev, _THIS_IP_, retval); + + return retval; +} + +/** + * 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) +{ + struct device *dev = container_of(work, struct device, power.work); + enum rpm_request req; + + spin_lock_irq(&dev->power.lock); + + if (!dev->power.request_pending) + goto out; + + req = dev->power.request; + dev->power.request = RPM_REQ_NONE; + dev->power.request_pending = false; + + switch (req) { + case RPM_REQ_NONE: + break; + case RPM_REQ_IDLE: + rpm_idle(dev, RPM_NOWAIT); + break; + case RPM_REQ_SUSPEND: + rpm_suspend(dev, RPM_NOWAIT); + break; + case RPM_REQ_AUTOSUSPEND: + rpm_suspend(dev, RPM_NOWAIT | RPM_AUTO); + break; + case RPM_REQ_RESUME: + rpm_resume(dev, RPM_NOWAIT); + break; + } + + out: + spin_unlock_irq(&dev->power.lock); +} + +/** + * pm_suspend_timer_fn - Timer function for pm_schedule_suspend(). + * @data: Device pointer passed by pm_schedule_suspend(). + * + * Check if the time is right and queue a suspend request. + */ +static void pm_suspend_timer_fn(struct timer_list *t) +{ + struct device *dev = from_timer(dev, t, power.suspend_timer); + unsigned long flags; + unsigned long expires; + + spin_lock_irqsave(&dev->power.lock, flags); + + expires = dev->power.timer_expires; + /* If 'expire' is after 'jiffies' we've been called too early. */ + if (expires > 0 && !time_after(expires, jiffies)) { + dev->power.timer_expires = 0; + rpm_suspend(dev, dev->power.timer_autosuspends ? + (RPM_ASYNC | RPM_AUTO) : RPM_ASYNC); + } + + spin_unlock_irqrestore(&dev->power.lock, flags); +} + +/** + * 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) +{ + unsigned long flags; + int retval; + + spin_lock_irqsave(&dev->power.lock, flags); + + if (!delay) { + retval = rpm_suspend(dev, RPM_ASYNC); + goto out; + } + + retval = rpm_check_suspend_allowed(dev); + if (retval) + goto out; + + /* Other scheduled or pending requests need to be canceled. */ + pm_runtime_cancel_pending(dev); + + dev->power.timer_expires = jiffies + msecs_to_jiffies(delay); + dev->power.timer_expires += !dev->power.timer_expires; + dev->power.timer_autosuspends = 0; + mod_timer(&dev->power.suspend_timer, dev->power.timer_expires); + + out: + spin_unlock_irqrestore(&dev->power.lock, flags); + + return retval; +} +EXPORT_SYMBOL_GPL(pm_schedule_suspend); + +/** + * __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. 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) +{ + unsigned long flags; + int retval; + + if (rpmflags & RPM_GET_PUT) { + if (!atomic_dec_and_test(&dev->power.usage_count)) + return 0; + } + + might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe); + + spin_lock_irqsave(&dev->power.lock, flags); + retval = rpm_idle(dev, rpmflags); + spin_unlock_irqrestore(&dev->power.lock, flags); + + return retval; +} +EXPORT_SYMBOL_GPL(__pm_runtime_idle); + +/** + * __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. 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) +{ + unsigned long flags; + int retval; + + if (rpmflags & RPM_GET_PUT) { + if (!atomic_dec_and_test(&dev->power.usage_count)) + return 0; + } + + might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe); + + spin_lock_irqsave(&dev->power.lock, flags); + retval = rpm_suspend(dev, rpmflags); + spin_unlock_irqrestore(&dev->power.lock, flags); + + return retval; +} +EXPORT_SYMBOL_GPL(__pm_runtime_suspend); + +/** + * __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) +{ + unsigned long flags; + int retval; + + might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe && + dev->power.runtime_status != RPM_ACTIVE); + + if (rpmflags & RPM_GET_PUT) + atomic_inc(&dev->power.usage_count); + + spin_lock_irqsave(&dev->power.lock, flags); + retval = rpm_resume(dev, rpmflags); + spin_unlock_irqrestore(&dev->power.lock, flags); + + return retval; +} +EXPORT_SYMBOL_GPL(__pm_runtime_resume); + +/** + * pm_runtime_get_if_in_use - Conditionally bump up the device's usage counter. + * @dev: Device to handle. + * + * Return -EINVAL if runtime PM is disabled for the device. + * + * If that's not the case and if the device's runtime PM status is RPM_ACTIVE + * and the runtime PM usage counter is nonzero, increment the counter and + * return 1. Otherwise return 0 without changing the counter. + */ +int pm_runtime_get_if_in_use(struct device *dev) +{ + unsigned long flags; + int retval; + + spin_lock_irqsave(&dev->power.lock, flags); + retval = dev->power.disable_depth > 0 ? -EINVAL : + dev->power.runtime_status == RPM_ACTIVE + && atomic_inc_not_zero(&dev->power.usage_count); + spin_unlock_irqrestore(&dev->power.lock, flags); + return retval; +} +EXPORT_SYMBOL_GPL(pm_runtime_get_if_in_use); + +/** + * __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. + */ +int __pm_runtime_set_status(struct device *dev, unsigned int status) +{ + struct device *parent = dev->parent; + unsigned long flags; + bool notify_parent = false; + int error = 0; + + if (status != RPM_ACTIVE && status != RPM_SUSPENDED) + return -EINVAL; + + spin_lock_irqsave(&dev->power.lock, flags); + + if (!dev->power.runtime_error && !dev->power.disable_depth) { + error = -EAGAIN; + goto out; + } + + if (dev->power.runtime_status == status || !parent) + goto out_set; + + if (status == RPM_SUSPENDED) { + atomic_add_unless(&parent->power.child_count, -1, 0); + notify_parent = !parent->power.ignore_children; + } else { + spin_lock_nested(&parent->power.lock, SINGLE_DEPTH_NESTING); + + /* + * It is invalid to put an active child under a parent that is + * not active, has runtime PM enabled and the + * 'power.ignore_children' flag unset. + */ + if (!parent->power.disable_depth + && !parent->power.ignore_children + && parent->power.runtime_status != RPM_ACTIVE) { + dev_err(dev, "runtime PM trying to activate child device %s but parent (%s) is not active\n", + dev_name(dev), + dev_name(parent)); + error = -EBUSY; + } else if (dev->power.runtime_status == RPM_SUSPENDED) { + atomic_inc(&parent->power.child_count); + } + + spin_unlock(&parent->power.lock); + + if (error) + goto out; + } + + out_set: + __update_runtime_status(dev, status); + dev->power.runtime_error = 0; + out: + spin_unlock_irqrestore(&dev->power.lock, flags); + + if (notify_parent) + pm_request_idle(parent); + + return error; +} +EXPORT_SYMBOL_GPL(__pm_runtime_set_status); + +/** + * __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_deactivate_timer(dev); + + if (dev->power.request_pending) { + dev->power.request = RPM_REQ_NONE; + spin_unlock_irq(&dev->power.lock); + + cancel_work_sync(&dev->power.work); + + spin_lock_irq(&dev->power.lock); + dev->power.request_pending = false; + } + + if (dev->power.runtime_status == RPM_SUSPENDING + || dev->power.runtime_status == RPM_RESUMING + || dev->power.idle_notification) { + DEFINE_WAIT(wait); + + /* Suspend, wake-up or idle notification in progress. */ + for (;;) { + prepare_to_wait(&dev->power.wait_queue, &wait, + TASK_UNINTERRUPTIBLE); + if (dev->power.runtime_status != RPM_SUSPENDING + && dev->power.runtime_status != RPM_RESUMING + && !dev->power.idle_notification) + break; + spin_unlock_irq(&dev->power.lock); + + schedule(); + + spin_lock_irq(&dev->power.lock); + } + finish_wait(&dev->power.wait_queue, &wait); + } +} + +/** + * 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) +{ + int retval = 0; + + pm_runtime_get_noresume(dev); + spin_lock_irq(&dev->power.lock); + + if (dev->power.request_pending + && dev->power.request == RPM_REQ_RESUME) { + rpm_resume(dev, 0); + retval = 1; + } + + __pm_runtime_barrier(dev); + + spin_unlock_irq(&dev->power.lock); + pm_runtime_put_noidle(dev); + + return retval; +} +EXPORT_SYMBOL_GPL(pm_runtime_barrier); + +/** + * __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) +{ + spin_lock_irq(&dev->power.lock); + + if (dev->power.disable_depth > 0) { + dev->power.disable_depth++; + goto out; + } + + /* + * Wake up the device if there's a resume request pending, because that + * means there probably is some I/O to process and disabling runtime PM + * shouldn't prevent the device from processing the I/O. + */ + if (check_resume && dev->power.request_pending + && dev->power.request == RPM_REQ_RESUME) { + /* + * Prevent suspends and idle notifications from being carried + * out after we have woken up the device. + */ + pm_runtime_get_noresume(dev); + + rpm_resume(dev, 0); + + pm_runtime_put_noidle(dev); + } + + if (!dev->power.disable_depth++) + __pm_runtime_barrier(dev); + + out: + spin_unlock_irq(&dev->power.lock); +} +EXPORT_SYMBOL_GPL(__pm_runtime_disable); + +/** + * pm_runtime_enable - Enable runtime PM of a device. + * @dev: Device to handle. + */ +void pm_runtime_enable(struct device *dev) +{ + unsigned long flags; + + spin_lock_irqsave(&dev->power.lock, flags); + + if (dev->power.disable_depth > 0) + dev->power.disable_depth--; + else + dev_warn(dev, "Unbalanced %s!\n", __func__); + + WARN(!dev->power.disable_depth && + dev->power.runtime_status == RPM_SUSPENDED && + !dev->power.ignore_children && + atomic_read(&dev->power.child_count) > 0, + "Enabling runtime PM for inactive device (%s) with active children\n", + dev_name(dev)); + + spin_unlock_irqrestore(&dev->power.lock, flags); +} +EXPORT_SYMBOL_GPL(pm_runtime_enable); + +/** + * 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) +{ + spin_lock_irq(&dev->power.lock); + if (!dev->power.runtime_auto) + goto out; + + dev->power.runtime_auto = false; + atomic_inc(&dev->power.usage_count); + rpm_resume(dev, 0); + + out: + spin_unlock_irq(&dev->power.lock); +} +EXPORT_SYMBOL_GPL(pm_runtime_forbid); + +/** + * 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) +{ + spin_lock_irq(&dev->power.lock); + if (dev->power.runtime_auto) + goto out; + + dev->power.runtime_auto = true; + if (atomic_dec_and_test(&dev->power.usage_count)) + rpm_idle(dev, RPM_AUTO | RPM_ASYNC); + + out: + spin_unlock_irq(&dev->power.lock); +} +EXPORT_SYMBOL_GPL(pm_runtime_allow); + +/** + * 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) +{ + spin_lock_irq(&dev->power.lock); + dev->power.no_callbacks = 1; + spin_unlock_irq(&dev->power.lock); + if (device_is_registered(dev)) + rpm_sysfs_remove(dev); +} +EXPORT_SYMBOL_GPL(pm_runtime_no_callbacks); + +/** + * 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) +{ + if (dev->parent) + pm_runtime_get_sync(dev->parent); + spin_lock_irq(&dev->power.lock); + dev->power.irq_safe = 1; + spin_unlock_irq(&dev->power.lock); +} +EXPORT_SYMBOL_GPL(pm_runtime_irq_safe); + +/** + * 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) +{ + int delay = dev->power.autosuspend_delay; + + /* Should runtime suspend be prevented now? */ + if (dev->power.use_autosuspend && delay < 0) { + + /* If it used to be allowed then prevent it. */ + if (!old_use || old_delay >= 0) { + atomic_inc(&dev->power.usage_count); + rpm_resume(dev, 0); + } + } + + /* Runtime suspend should be allowed now. */ + else { + + /* If it used to be prevented then allow it. */ + if (old_use && old_delay < 0) + atomic_dec(&dev->power.usage_count); + + /* Maybe we can autosuspend now. */ + rpm_idle(dev, RPM_AUTO); + } +} + +/** + * 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) +{ + int old_delay, old_use; + + spin_lock_irq(&dev->power.lock); + old_delay = dev->power.autosuspend_delay; + old_use = dev->power.use_autosuspend; + dev->power.autosuspend_delay = delay; + update_autosuspend(dev, old_delay, old_use); + spin_unlock_irq(&dev->power.lock); +} +EXPORT_SYMBOL_GPL(pm_runtime_set_autosuspend_delay); + +/** + * __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) +{ + int old_delay, old_use; + + spin_lock_irq(&dev->power.lock); + old_delay = dev->power.autosuspend_delay; + old_use = dev->power.use_autosuspend; + dev->power.use_autosuspend = use; + update_autosuspend(dev, old_delay, old_use); + spin_unlock_irq(&dev->power.lock); +} +EXPORT_SYMBOL_GPL(__pm_runtime_use_autosuspend); + +/** + * pm_runtime_init - Initialize runtime PM fields in given device object. + * @dev: Device object to initialize. + */ +void pm_runtime_init(struct device *dev) +{ + dev->power.runtime_status = RPM_SUSPENDED; + dev->power.idle_notification = false; + + dev->power.disable_depth = 1; + atomic_set(&dev->power.usage_count, 0); + + dev->power.runtime_error = 0; + + atomic_set(&dev->power.child_count, 0); + pm_suspend_ignore_children(dev, false); + dev->power.runtime_auto = true; + + dev->power.request_pending = false; + dev->power.request = RPM_REQ_NONE; + dev->power.deferred_resume = false; + dev->power.accounting_timestamp = jiffies; + INIT_WORK(&dev->power.work, pm_runtime_work); + + dev->power.timer_expires = 0; + timer_setup(&dev->power.suspend_timer, pm_suspend_timer_fn, 0); + + init_waitqueue_head(&dev->power.wait_queue); +} + +/** + * 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) +{ + if (!pm_runtime_enabled(dev)) { + if (dev->power.runtime_status == RPM_ACTIVE) + pm_runtime_set_suspended(dev); + if (dev->power.irq_safe) { + spin_lock_irq(&dev->power.lock); + dev->power.irq_safe = 0; + spin_unlock_irq(&dev->power.lock); + if (dev->parent) + pm_runtime_put(dev->parent); + } + } +} + +/** + * 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_disable(dev, false); + pm_runtime_reinit(dev); +} + +/** + * pm_runtime_clean_up_links - Prepare links to consumers for driver removal. + * @dev: Device whose driver is going to be removed. + * + * Check links from this device to any consumers and if any of them have active + * runtime PM references to the device, drop the usage counter of the device + * (as many times as needed). + * + * Links with the DL_FLAG_MANAGED flag unset are ignored. + * + * Since the device is guaranteed to be runtime-active at the point this is + * called, nothing else needs to be done here. + * + * Moreover, this is called after device_links_busy() has returned 'false', so + * the status of each link is guaranteed to be DL_STATE_SUPPLIER_UNBIND and + * therefore rpm_active can't be manipulated concurrently. + */ +void pm_runtime_clean_up_links(struct device *dev) +{ + struct device_link *link; + int idx; + + idx = device_links_read_lock(); + + list_for_each_entry_rcu(link, &dev->links.consumers, s_node) { + if (!(link->flags & DL_FLAG_MANAGED)) + continue; + + while (refcount_dec_not_one(&link->rpm_active)) + pm_runtime_put_noidle(dev); + } + + device_links_read_unlock(idx); +} + +/** + * pm_runtime_get_suppliers - Resume and reference-count supplier devices. + * @dev: Consumer device. + */ +void pm_runtime_get_suppliers(struct device *dev) +{ + struct device_link *link; + int idx; + + idx = device_links_read_lock(); + + list_for_each_entry_rcu(link, &dev->links.suppliers, c_node) + if (link->flags & DL_FLAG_PM_RUNTIME) { + link->supplier_preactivated = true; + pm_runtime_get_sync(link->supplier); + refcount_inc(&link->rpm_active); + } + + device_links_read_unlock(idx); +} + +/** + * pm_runtime_put_suppliers - Drop references to supplier devices. + * @dev: Consumer device. + */ +void pm_runtime_put_suppliers(struct device *dev) +{ + struct device_link *link; + unsigned long flags; + bool put; + int idx; + + idx = device_links_read_lock(); + + list_for_each_entry_rcu(link, &dev->links.suppliers, c_node) + if (link->supplier_preactivated) { + link->supplier_preactivated = false; + spin_lock_irqsave(&dev->power.lock, flags); + put = pm_runtime_status_suspended(dev) && + refcount_dec_not_one(&link->rpm_active); + spin_unlock_irqrestore(&dev->power.lock, flags); + if (put) + pm_runtime_put(link->supplier); + } + + device_links_read_unlock(idx); +} + +void pm_runtime_new_link(struct device *dev) +{ + spin_lock_irq(&dev->power.lock); + dev->power.links_count++; + spin_unlock_irq(&dev->power.lock); +} + +void pm_runtime_drop_link(struct device *dev) +{ + spin_lock_irq(&dev->power.lock); + WARN_ON(dev->power.links_count == 0); + dev->power.links_count--; + spin_unlock_irq(&dev->power.lock); +} + +static bool pm_runtime_need_not_resume(struct device *dev) +{ + return atomic_read(&dev->power.usage_count) <= 1 && + (atomic_read(&dev->power.child_count) == 0 || + dev->power.ignore_children); +} + +/** + * 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. + */ +int pm_runtime_force_suspend(struct device *dev) +{ + int (*callback)(struct device *); + int ret; + + pm_runtime_disable(dev); + if (pm_runtime_status_suspended(dev)) + return 0; + + callback = RPM_GET_CALLBACK(dev, runtime_suspend); + + ret = callback ? callback(dev) : 0; + if (ret) + goto err; + + /* + * If the device can stay in suspend after the system-wide transition + * to the working state that will follow, drop the children counter of + * its parent, but set its status to RPM_SUSPENDED anyway in case this + * function will be called again for it in the meantime. + */ + if (pm_runtime_need_not_resume(dev)) + pm_runtime_set_suspended(dev); + else + __update_runtime_status(dev, RPM_SUSPENDED); + + return 0; + +err: + pm_runtime_enable(dev); + return ret; +} +EXPORT_SYMBOL_GPL(pm_runtime_force_suspend); + +/** + * 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) +{ + int (*callback)(struct device *); + int ret = 0; + + if (!pm_runtime_status_suspended(dev) || pm_runtime_need_not_resume(dev)) + goto out; + + /* + * The value of the parent's children counter is correct already, so + * just update the status of the device. + */ + __update_runtime_status(dev, RPM_ACTIVE); + + callback = RPM_GET_CALLBACK(dev, runtime_resume); + + ret = callback ? callback(dev) : 0; + if (ret) { + pm_runtime_set_suspended(dev); + goto out; + } + + pm_runtime_mark_last_busy(dev); +out: + pm_runtime_enable(dev); + return ret; +} +EXPORT_SYMBOL_GPL(pm_runtime_force_resume); |