diff options
| -rw-r--r-- | Documentation/power/runtime_pm.txt | 378 | ||||
| -rw-r--r-- | drivers/base/dd.c | 11 | ||||
| -rw-r--r-- | drivers/base/power/Makefile | 1 | ||||
| -rw-r--r-- | drivers/base/power/main.c | 22 | ||||
| -rw-r--r-- | drivers/base/power/power.h | 31 | ||||
| -rw-r--r-- | drivers/base/power/runtime.c | 1011 | ||||
| -rw-r--r-- | include/linux/pm.h | 101 | ||||
| -rw-r--r-- | include/linux/pm_runtime.h | 114 | ||||
| -rw-r--r-- | kernel/power/Kconfig | 14 | ||||
| -rw-r--r-- | kernel/power/main.c | 17 |
10 files changed, 1689 insertions, 11 deletions
diff --git a/Documentation/power/runtime_pm.txt b/Documentation/power/runtime_pm.txt new file mode 100644 index 00000000000..f49a33b704d --- /dev/null +++ b/Documentation/power/runtime_pm.txt @@ -0,0 +1,378 @@ +Run-time Power Management Framework for I/O Devices + +(C) 2009 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc. + +1. Introduction + +Support for run-time power management (run-time PM) of I/O devices is provided +at the power management core (PM core) level by means of: + +* The power management workqueue pm_wq in which bus types and device drivers can + put their PM-related work items. It is strongly recommended that pm_wq be + used for queuing all work items related to run-time PM, because this allows + them to be synchronized with system-wide power transitions (suspend to RAM, + hibernation and resume from system sleep states). pm_wq is declared in + include/linux/pm_runtime.h and defined in kernel/power/main.c. + +* A number of run-time PM fields in the 'power' member of 'struct device' (which + is of the type 'struct dev_pm_info', defined in include/linux/pm.h) that can + be used for synchronizing run-time PM operations with one another. + +* Three device run-time PM callbacks in 'struct dev_pm_ops' (defined in + include/linux/pm.h). + +* A set of helper functions defined in drivers/base/power/runtime.c that can be + used for carrying out run-time PM operations in such a way that the + synchronization between them is taken care of by the PM core. Bus types and + device drivers are encouraged to use these functions. + +The run-time PM callbacks present in 'struct dev_pm_ops', the device run-time PM +fields of 'struct dev_pm_info' and the core helper functions provided for +run-time PM are described below. + +2. Device Run-time PM Callbacks + +There are three device run-time PM callbacks defined in 'struct dev_pm_ops': + +struct dev_pm_ops { + ... + int (*runtime_suspend)(struct device *dev); + int (*runtime_resume)(struct device *dev); + void (*runtime_idle)(struct device *dev); + ... +}; + +The ->runtime_suspend() callback is executed by the PM core for the bus type of +the device being suspended. The bus type's callback is then _entirely_ +_responsible_ for handling the device as appropriate, which may, but need not +include executing the device driver's own ->runtime_suspend() callback (from the +PM core's point of view it is not necessary to implement a ->runtime_suspend() +callback in a device driver as long as the bus type's ->runtime_suspend() knows +what to do to handle the device). + + * Once the bus type's ->runtime_suspend() callback has completed successfully + for given device, the PM core regards the device as suspended, which need + not mean that the device has been put into a low power state. It is + supposed to mean, however, that the device will not process data and will + not communicate with the CPU(s) and RAM until its bus type's + ->runtime_resume() callback is executed for it. The run-time PM status of + a device after successful execution of its bus type's ->runtime_suspend() + callback is 'suspended'. + + * If the bus type's ->runtime_suspend() callback returns -EBUSY or -EAGAIN, + the device's run-time PM status is supposed to be 'active', which means that + the device _must_ be fully operational afterwards. + + * If the bus type's ->runtime_suspend() callback returns an error code + different from -EBUSY or -EAGAIN, the PM core regards this as a fatal + error and will refuse to run the helper functions described in Section 4 + for the device, until the status of it is directly set either to 'active' + or to 'suspended' (the PM core provides special helper functions for this + purpose). + +In particular, if the driver requires remote wakeup capability for proper +functioning and device_may_wakeup() returns 'false' for the device, then +->runtime_suspend() should return -EBUSY. On the other hand, if +device_may_wakeup() returns 'true' for the device and the device is put +into a low power state during the execution of its bus type's +->runtime_suspend(), it is expected that remote wake-up (i.e. hardware mechanism +allowing the device to request a change of its power state, such as PCI PME) +will be enabled for the device. Generally, remote wake-up should be enabled +for all input devices put into a low power state at run time. + +The ->runtime_resume() callback is executed by the PM core for the bus type of +the device being woken up. The bus type's callback is then _entirely_ +_responsible_ for handling the device as appropriate, which may, but need not +include executing the device driver's own ->runtime_resume() callback (from the +PM core's point of view it is not necessary to implement a ->runtime_resume() +callback in a device driver as long as the bus type's ->runtime_resume() knows +what to do to handle the device). + + * Once the bus type's ->runtime_resume() callback has completed successfully, + the PM core regards the device as fully operational, which means that the + device _must_ be able to complete I/O operations as needed. The run-time + PM status of the device is then 'active'. + + * If the bus type's ->runtime_resume() callback returns an error code, the PM + core regards this as a fatal error and will refuse to run the helper + functions described in Section 4 for the device, until its status is + directly set either to 'active' or to 'suspended' (the PM core provides + special helper functions for this purpose). + +The ->runtime_idle() callback is executed by the PM core for the bus type of +given device whenever the device appears to be idle, which is indicated to the +PM core by two counters, the device's usage counter and the counter of 'active' +children of the device. + + * If any of these counters is decreased using a helper function provided by + the PM core and it turns out to be equal to zero, the other counter is + checked. If that counter also is equal to zero, the PM core executes the + device bus type's ->runtime_idle() callback (with the device as an + argument). + +The action performed by a bus type's ->runtime_idle() callback is totally +dependent on the bus type in question, but the expected and recommended action +is to check if the device can be suspended (i.e. if all of the conditions +necessary for suspending the device are satisfied) and to queue up a suspend +request for the device in that case. + +The helper functions provided by the PM core, described in Section 4, guarantee +that the following constraints are met with respect to the bus type's run-time +PM callbacks: + +(1) The callbacks are mutually exclusive (e.g. it is forbidden to execute + ->runtime_suspend() in parallel with ->runtime_resume() or with another + instance of ->runtime_suspend() for the same device) with the exception that + ->runtime_suspend() or ->runtime_resume() can be executed in parallel with + ->runtime_idle() (although ->runtime_idle() will not be started while any + of the other callbacks is being executed for the same device). + +(2) ->runtime_idle() and ->runtime_suspend() can only be executed for 'active' + devices (i.e. the PM core will only execute ->runtime_idle() or + ->runtime_suspend() for the devices the run-time PM status of which is + 'active'). + +(3) ->runtime_idle() and ->runtime_suspend() can only be executed for a device + the usage counter of which is equal to zero _and_ either the counter of + 'active' children of which is equal to zero, or the 'power.ignore_children' + flag of which is set. + +(4) ->runtime_resume() can only be executed for 'suspended' devices (i.e. the + PM core will only execute ->runtime_resume() for the devices the run-time + PM status of which is 'suspended'). + +Additionally, the helper functions provided by the PM core obey the following +rules: + + * If ->runtime_suspend() is about to be executed or there's a pending request + to execute it, ->runtime_idle() will not be executed for the same device. + + * A request to execute or to schedule the execution of ->runtime_suspend() + will cancel any pending requests to execute ->runtime_idle() for the same + device. + + * If ->runtime_resume() is about to be executed or there's a pending request + to execute it, the other callbacks will not be executed for the same device. + + * A request to execute ->runtime_resume() will cancel any pending or + scheduled requests to execute the other callbacks for the same device. + +3. Run-time PM Device Fields + +The following device run-time PM fields are present in 'struct dev_pm_info', as +defined in include/linux/pm.h: + + struct timer_list suspend_timer; + - timer used for scheduling (delayed) suspend request + + unsigned long timer_expires; + - timer expiration time, in jiffies (if this is different from zero, the + timer is running and will expire at that time, otherwise the timer is not + running) + + struct work_struct work; + - work structure used for queuing up requests (i.e. work items in pm_wq) + + wait_queue_head_t wait_queue; + - wait queue used if any of the helper functions needs to wait for another + one to complete + + spinlock_t lock; + - lock used for synchronisation + + atomic_t usage_count; + - the usage counter of the device + + atomic_t child_count; + - the count of 'active' children of the device + + unsigned int ignore_children; + - if set, the value of child_count is ignored (but still updated) + + unsigned int disable_depth; + - used for disabling the helper funcions (they work normally if this is + equal to zero); the initial value of it is 1 (i.e. run-time PM is + initially disabled for all devices) + + unsigned int runtime_error; + - if set, there was a fatal error (one of the callbacks returned error code + as described in Section 2), so the helper funtions will not work until + this flag is cleared; this is the error code returned by the failing + callback + + unsigned int idle_notification; + - if set, ->runtime_idle() is being executed + + unsigned int request_pending; + - if set, there's a pending request (i.e. a work item queued up into pm_wq) + + enum rpm_request request; + - type of request that's pending (valid if request_pending is set) + + unsigned int deferred_resume; + - set if ->runtime_resume() is about to be run while ->runtime_suspend() is + being executed for that device and it is not practical to wait for the + suspend to complete; means "start a resume as soon as you've suspended" + + enum rpm_status runtime_status; + - the run-time PM status of the device; this field's initial value is + RPM_SUSPENDED, which means that each device is initially regarded by the + PM core as 'suspended', regardless of its real hardware status + +All of the above fields are members of the 'power' member of 'struct device'. + +4. Run-time PM Device Helper Functions + +The following run-time PM helper functions are defined in +drivers/base/power/runtime.c and include/linux/pm_runtime.h: + + void pm_runtime_init(struct device *dev); + - initialize the device run-time PM fields in 'struct dev_pm_info' + + void pm_runtime_remove(struct device *dev); + - make sure that the run-time PM of the device will be disabled after + removing the device from device hierarchy + + int pm_runtime_idle(struct device *dev); + - execute ->runtime_idle() for the device's bus type; returns 0 on success + or error code on failure, where -EINPROGRESS means that ->runtime_idle() + is already being executed + + int pm_runtime_suspend(struct device *dev); + - execute ->runtime_suspend() for the device's bus type; returns 0 on + success, 1 if the device's run-time PM status was already 'suspended', or + error code on failure, where -EAGAIN or -EBUSY means it is safe to attempt + to suspend the device again in future + + int pm_runtime_resume(struct device *dev); + - execute ->runtime_resume() for the device's bus type; returns 0 on + success, 1 if the device's run-time PM status was already 'active' or + error code on failure, where -EAGAIN means it may be safe to attempt to + resume the device again in future, but 'power.runtime_error' should be + checked additionally + + int pm_request_idle(struct device *dev); + - submit a request to execute ->runtime_idle() for the device's bus type + (the request is represented by a work item in pm_wq); returns 0 on success + or error code if the request has not been queued up + + int pm_schedule_suspend(struct device *dev, unsigned int delay); + - schedule the execution of ->runtime_suspend() for the device's bus type + in future, where 'delay' is the time to wait before queuing up a suspend + work item in pm_wq, in milliseconds (if 'delay' is zero, the work item is + queued up immediately); returns 0 on success, 1 if the device's PM + run-time status was already 'suspended', or error code if the request + hasn't been scheduled (or queued up if 'delay' is 0); if the execution of + ->runtime_suspend() is already scheduled and not yet expired, the new + value of 'delay' will be used as the time to wait + + int pm_request_resume(struct device *dev); + - submit a request to execute ->runtime_resume() for the device's bus type + (the request is represented by a work item in pm_wq); returns 0 on + success, 1 if the device's run-time PM status was already 'active', or + error code if the request hasn't been queued up + + void pm_runtime_get_noresume(struct device *dev); + - increment the device's usage counter + + int pm_runtime_get(struct device *dev); + - increment the device's usage counter, run pm_request_resume(dev) and + return its result + + int pm_runtime_get_sync(struct device *dev); + - increment the device's usage counter, run pm_runtime_resume(dev) and + return its result + + void pm_runtime_put_noidle(struct device *dev); + - decrement the device's usage counter + + int pm_runtime_put(struct device *dev); + - decrement the device's usage counter, run pm_request_idle(dev) and return + its result + + int pm_runtime_put_sync(struct device *dev); + - decrement the device's usage counter, run pm_runtime_idle(dev) and return + its result + + void pm_runtime_enable(struct device *dev); + - enable the run-time PM helper functions to run the device bus type's + run-time PM callbacks described in Section 2 + + int pm_runtime_disable(struct device *dev); + - prevent the run-time PM helper functions from running the device bus + type's run-time PM callbacks, make sure that all of the pending run-time + PM operations on the device are either completed or canceled; returns + 1 if there was a resume request pending and it was necessary to execute + ->runtime_resume() for the device's bus type to satisfy that request, + otherwise 0 is returned + + void pm_suspend_ignore_children(struct device *dev, bool enable); + - set/unset the power.ignore_children flag of the device + + int pm_runtime_set_active(struct device *dev); + - clear the device's 'power.runtime_error' flag, set the device's run-time + PM status to 'active' and update its parent's counter of 'active' + children as appropriate (it is only valid to use this function if + 'power.runtime_error' is set or 'power.disable_depth' is greater than + zero); it will fail and return error code if the device has a parent + which is not active and the 'power.ignore_children' flag of which is unset + + void pm_runtime_set_suspended(struct device *dev); + - clear the device's 'power.runtime_error' flag, set the device's run-time + PM status to 'suspended' and update its parent's counter of 'active' + children as appropriate (it is only valid to use this function if + 'power.runtime_error' is set or 'power.disable_depth' is greater than + zero) + +It is safe to execute the following helper functions from interrupt context: + +pm_request_idle() +pm_schedule_suspend() +pm_request_resume() +pm_runtime_get_noresume() +pm_runtime_get() +pm_runtime_put_noidle() +pm_runtime_put() +pm_suspend_ignore_children() +pm_runtime_set_active() +pm_runtime_set_suspended() +pm_runtime_enable() + +5. Run-time PM Initialization, Device Probing and Removal + +Initially, the run-time PM is disabled for all devices, which means that the +majority of the run-time PM helper funtions described in Section 4 will return +-EAGAIN until pm_runtime_enable() is called for the device. + +In addition to that, the initial run-time PM status of all devices is +'suspended', but it need not reflect the actual physical state of the device. +Thus, if the device is initially active (i.e. it is able to process I/O), its +run-time PM status must be changed to 'active', with the help of +pm_runtime_set_active(), before pm_runtime_enable() is called for the device. + +However, if the device has a parent and the parent's run-time PM is enabled, +calling pm_runtime_set_active() for the device will affect the parent, unless +the parent's 'power.ignore_children' flag is set. Namely, in that case the +parent won't be able to suspend at run time, using the PM core's helper +functions, as long as the child's status is 'active', even if the child's +run-time PM is still disabled (i.e. pm_runtime_enable() hasn't been called for +the child yet or pm_runtime_disable() has been called for it). For this reason, +once pm_runtime_set_active() has been called for the device, pm_runtime_enable() +should be called for it too as soon as reasonably possible or its run-time PM +status should be changed back to 'suspended' with the help of +pm_runtime_set_suspended(). + +If the default initial run-time PM status of the device (i.e. 'suspended') +reflects the actual state of the device, its bus type's or its driver's +->probe() callback will likely need to wake it up using one of the PM core's +helper functions described in Section 4. In that case, pm_runtime_resume() +should be used. Of course, for this purpose the device's run-time PM has to be +enabled earlier by calling pm_runtime_enable(). + +If the device bus type's or driver's ->probe() or ->remove() callback runs +pm_runtime_suspend() or pm_runtime_idle() or their asynchronous counterparts, +they will fail returning -EAGAIN, because the device's usage counter is +incremented by the core before executing ->probe() and ->remove(). Still, it +may be desirable to suspend the device as soon as ->probe() or ->remove() has +finished, so the PM core uses pm_runtime_idle_sync() to invoke the device bus +type's ->runtime_idle() callback at that time. diff --git a/drivers/base/dd.c b/drivers/base/dd.c index f0106875f01..7b34b3a48f6 100644 --- a/drivers/base/dd.c +++ b/drivers/base/dd.c @@ -23,6 +23,7 @@ #include <linux/kthread.h> #include <linux/wait.h> #include <linux/async.h> +#include <linux/pm_runtime.h> #include "base.h" #include "power/power.h" @@ -202,7 +203,10 @@ int driver_probe_device(struct device_driver *drv, struct device *dev) pr_debug("bus: '%s': %s: matched device %s with driver %s\n", drv->bus->name, __func__, dev_name(dev), drv->name); + pm_runtime_get_noresume(dev); + pm_runtime_barrier(dev); ret = really_probe(dev, drv); + pm_runtime_put_sync(dev); return ret; } @@ -245,7 +249,9 @@ int device_attach(struct device *dev) ret = 0; } } else { + pm_runtime_get_noresume(dev); ret = bus_for_each_drv(dev->bus, NULL, dev, __device_attach); + pm_runtime_put_sync(dev); } up(&dev->sem); return ret; @@ -306,6 +312,9 @@ static void __device_release_driver(struct device *dev) drv = dev->driver; if (drv) { + pm_runtime_get_noresume(dev); + pm_runtime_barrier(dev); + driver_sysfs_remove(dev); if (dev->bus) @@ -324,6 +333,8 @@ static void __device_release_driver(struct device *dev) blocking_notifier_call_chain(&dev->bus->p->bus_notifier, BUS_NOTIFY_UNBOUND_DRIVER, dev); + + pm_runtime_put_sync(dev); } } diff --git a/drivers/base/power/Makefile b/drivers/base/power/Makefile index 911208b8925..3ce3519e8f3 100644 --- a/drivers/base/power/Makefile +++ b/drivers/base/power/Makefile @@ -1,5 +1,6 @@ obj-$(CONFIG_PM) += sysfs.o obj-$(CONFIG_PM_SLEEP) += main.o +obj-$(CONFIG_PM_RUNTIME) += runtime.o obj-$(CONFIG_PM_TRACE_RTC) += trace.o ccflags-$(CONFIG_DEBUG_DRIVER) := -DDEBUG diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c index 1b1a786b7de..86990011277 100644 --- a/drivers/base/power/main.c +++ b/drivers/base/power/main.c @@ -21,6 +21,7 @@ #include <linux/kallsyms.h> #include <linux/mutex.h> #include <linux/pm.h> +#include <linux/pm_runtime.h> #include <linux/resume-trace.h> #include <linux/rwsem.h> #include <linux/interrupt.h> @@ -49,6 +50,16 @@ static DEFINE_MUTEX(dpm_list_mtx); static bool transition_started; /** + * device_pm_init - Initialize the PM-related part of a device object + * @dev: Device object being initialized. + */ +void device_pm_init(struct device *dev) +{ + dev->power.status = DPM_ON; + pm_runtime_init(dev); +} + +/** * device_pm_lock - lock the list of active devices used by the PM core */ void device_pm_lock(void) @@ -105,6 +116,7 @@ void device_pm_remove(struct device *dev) mutex_lock(&dpm_list_mtx); list_del_init(&dev->power.entry); mutex_unlock(&dpm_list_mtx); + pm_runtime_remove(dev); } /** @@ -512,6 +524,7 @@ static void dpm_complete(pm_message_t state) mutex_unlock(&dpm_list_mtx); device_complete(dev, state); + pm_runtime_put_noidle(dev); mutex_lock(&dpm_list_mtx); } @@ -757,7 +770,14 @@ static int dpm_prepare(pm_message_t state) dev->power.status = DPM_PREPARING; mutex_unlock(&dpm_list_mtx); - error = device_prepare(dev, state); + pm_runtime_get_noresume(dev); + if (pm_runtime_barrier(dev) && device_may_wakeup(dev)) { + /* Wake-up requested during system sleep transition. */ + pm_runtime_put_noidle(dev); + error = -EBUSY; + } else { + error = device_prepare(dev, state); + } mutex_lock(&dpm_list_mtx); if (error) { diff --git a/drivers/base/power/power.h b/drivers/base/power/power.h index c7cb4fc3735..b8fa1aa5225 100644 --- a/drivers/base/power/power.h +++ b/drivers/base/power/power.h @@ -1,7 +1,14 @@ -static inline void device_pm_init(struct device *dev) -{ - dev->power.status = DPM_ON; -} +#ifdef CONFIG_PM_RUNTIME + +extern void pm_runtime_init(struct device *dev); +extern void pm_runtime_remove(struct device *dev); + +#else /* !CONFIG_PM_RUNTIME */ + +static inline void pm_runtime_init(struct device *dev) {} +static inline void pm_runtime_remove(struct device *dev) {} + +#endif /* !CONFIG_PM_RUNTIME */ #ifdef CONFIG_PM_SLEEP @@ -16,23 +23,33 @@ static inline struct device *to_device(struct list_head *entry) return container_of(entry, struct device, power.entry); } +extern void device_pm_init(struct device *dev); extern void device_pm_add(struct device *); extern void device_pm_remove(struct device *); extern void device_pm_move_before(struct device *, struct device *); extern void device_pm_move_after(struct device *, struct device *); extern void device_pm_move_last(struct device *); -#else /* CONFIG_PM_SLEEP */ +#else /* !CONFIG_PM_SLEEP */ + +static inline void device_pm_init(struct device *dev) +{ + pm_runtime_init(dev); +} + +static inline void device_pm_remove(struct device *dev) +{ + pm_runtime_remove(dev); +} static inline void device_pm_add(struct device *dev) {} -static inline void device_pm_remove(struct device *dev) {} static inline void device_pm_move_before(struct device *deva, struct device *devb) {} static inline void device_pm_move_after(struct device *deva, struct device *devb) {} static inline void device_pm_move_last(struct device *dev) {} -#endif +#endif /* !CONFIG_PM_SLEEP */ #ifdef CONFIG_PM diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c new file mode 100644 index 00000000000..38556f6cc22 --- /dev/null +++ b/drivers/base/power/runtime.c @@ -0,0 +1,1011 @@ +/* + * drivers/base/power/runtime.c - Helper functions for device run-time PM + * + * Copyright (c) 2009 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc. + * + * This file is released under the GPLv2. + */ + +#include <linux/sched.h> +#include <linux/pm_runtime.h> +#include <linux/jiffies.h> + +static int __pm_runtime_resume(struct device *dev, bool from_wq); +static int __pm_request_idle(struct device *dev); +static int __pm_request_resume(struct device *dev); + +/** + * 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_idle - Notify device bus type if the device can be suspended. + * @dev: Device to notify the bus type about. + * + * This function must be called under dev->power.lock with interrupts disabled. + */ +static int __pm_runtime_idle(struct device *dev) + __releases(&dev->power.lock) __acquires(&dev->power.lock) +{ + int retval = 0; + + dev_dbg(dev, "__pm_runtime_idle()!\n"); + + if (dev->power.runtime_error) + retval = -EINVAL; + else if (dev->power.idle_notification) + retval = -EINPROGRESS; + else if (atomic_read(&dev->power.usage_count) > 0 + || dev->power.disable_depth > 0 + || dev->power.runtime_status != RPM_ACTIVE) + retval = -EAGAIN; + else if (!pm_children_suspended(dev)) + retval = -EBUSY; + if (retval) + goto out; + + if (dev->power.request_pending) { + /* + * If an idle notification request is pending, cancel it. Any + * other pending request takes precedence over us. + */ + if (dev->power.request == RPM_REQ_IDLE) { + dev->power.request = RPM_REQ_NONE; + } else if (dev->power.request != RPM_REQ_NONE) { + retval = -EAGAIN; + goto out; + } + } + + dev->power.idle_notification = true; + + if (dev->bus && dev->bus->pm && dev->bus->pm->runtime_idle) { + spin_unlock_irq(&dev->power.lock); + + dev->bus->pm->runtime_idle(dev); + + spin_lock_irq(&dev->power.lock); + } + + dev->power.idle_notification = false; + wake_up_all(&dev->power.wait_queue); + + out: + dev_dbg(dev, "__pm_runtime_idle() returns %d!\n", retval); + + return retval; +} + +/** + * pm_runtime_idle - Notify device bus type if the device can be suspended. + * @dev: Device to notify the bus type about. + */ +int pm_runtime_idle(struct device *dev) +{ + int retval; + + spin_lock_irq(&dev->power.lock); + retval = __pm_runtime_idle(dev); + spin_unlock_irq(&dev->power.lock); + + return retval; +} +EXPORT_SYMBOL_GPL(pm_runtime_idle); + +/** + * __pm_runtime_suspend - Carry out run-time suspend of given device. + * @dev: Device to suspend. + * @from_wq: If set, the function has been called via pm_wq. + * + * Check if the device can be suspended and run the ->runtime_suspend() callback + * provided by its bus type. If another suspend has been started earlier, wait + * for it to finish. If an idle notification or suspend request is pending or + * scheduled, cancel it. + * + * This function must be called under dev->power.lock with interrupts disabled. + */ +int __pm_runtime_suspend(struct device *dev, bool from_wq) + __releases(&dev->power.lock) __acquires(&dev->power.lock) +{ + struct device *parent = NULL; + bool notify = false; + int retval = 0; + + dev_dbg(dev, "__pm_runtime_suspend()%s!\n", + from_wq ? " from workqueue" : ""); + + repeat: + if (dev->power.runtime_error) { + retval = -EINVAL; + goto out; + } + + /* Pending resume requests take precedence over us. */ + if (dev->power.request_pending + && dev->power.request == RPM_REQ_RESUME) { + retval = -EAGAIN; + goto out; + } + + /* Other scheduled or pending requests need to be canceled. */ + pm_runtime_cancel_pending(dev); + + if (dev->power.runtime_status == RPM_SUSPENDED) + retval = 1; + else if (dev->power.runtime_status == RPM_RESUMING + || dev->power.disable_depth > 0 + || atomic_read(&dev->power.usage_count) > 0) + retval = -EAGAIN; + else if (!pm_children_suspended(dev)) + retval = -EBUSY; + if (retval) + goto out; + + if (dev->power.runtime_status == RPM_SUSPENDING) { + DEFINE_WAIT(wait); + + if (from_wq) { + retval = -EINPROGRESS; + goto out; + } + + /* 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; + } + + dev->power.runtime_status = RPM_SUSPENDING; + + if (dev->bus && dev->bus->pm && dev->bus->pm->runtime_suspend) { + spin_unlock_irq(&dev->power.lock); + + retval = dev->bus->pm->runtime_suspend(dev); + + spin_lock_irq(&dev->power.lock); + dev->power.runtime_error = retval; + } else { + retval = -ENOSYS; + } + + if (retval) { + dev->power.runtime_status = RPM_ACTIVE; + pm_runtime_cancel_pending(dev); + dev->power.deferred_resume = false; + + if (retval == -EAGAIN || retval == -EBUSY) { + notify = true; + dev->power.runtime_error = 0; + } + } else { + dev->power.runtime_status = RPM_SUSPENDED; + + 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; + __pm_runtime_resume(dev, false); + retval = -EAGAIN; + goto out; + } + + if (notify) + __pm_runtime_idle(dev); + + if (parent && !parent->power.ignore_children) { + spin_unlock_irq(&dev->power.lock); + + pm_request_idle(parent); + + spin_lock_irq(&dev->power.lock); + } + + out: + dev_dbg(dev, "__pm_runtime_suspend() returns %d!\n", retval); + + return retval; +} + +/** + * pm_runtime_suspend - Carry out run-time suspend of given device. + * @dev: Device to suspend. + */ +int pm_runtime_suspend(struct device *dev) +{ + int retval; + + spin_lock_irq(&dev->power.lock); + retval = __pm_runtime_suspend(dev, false); + spin_unlock_irq(&dev->power.lock); + + return retval; +} +EXPORT_SYMBOL_GPL(pm_runtime_suspend); + +/** + * __pm_runtime_resume - Carry out run-time resume of given device. + * @dev: Device to resume. + * @from_wq: If set, the function has been called via pm_wq. + * + * Check if the device can be woken up and run the ->runtime_resume() callback + * provided by its bus type. If another resume has been started earlier, wait + * for it to finish. If there's a suspend running in parallel with this + * function, wait for it to finish and resume the device. Cancel any scheduled + * or pending requests. + * + * This function must be called under dev->power.lock with interrupts disabled. + */ +int __pm_runtime_resume(struct device *dev, bool from_wq) + __releases(&dev->power.lock) __acquires(&dev->power.lock) +{ + struct device *parent = NULL; + int retval = 0; + + dev_dbg(dev, "__pm_runtime_resume()%s!\n", + from_wq ? " from workqueue" : ""); + + repeat: + if (dev->power.runtime_error) { + retval = -EINVAL; + goto out; + } + + pm_runtime_cancel_pending(dev); + + if (dev->power.runtime_status == RPM_ACTIVE) + retval = 1; + else if (dev->power.disable_depth > 0) + retval = -EAGAIN; + if (retval) + goto out; + + if (dev->power.runtime_status == RPM_RESUMING + || dev->power.runtime_status == RPM_SUSPENDING) { + DEFINE_WAIT(wait); + + if (from_wq) { + if (dev->power.runtime_status == RPM_SUSPENDING) + dev->power.deferred_resume = true; + retval = -EINPROGRESS; + goto out; + } + + /* 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; + } + + if (!parent && dev->parent) { + /* + * Increment the parent's resume counter and resume it if + * necessary. + */ + parent = dev->parent; + spin_unlock_irq(&dev->power.lock); + + pm_runtime_get_noresume(parent); + + spin_lock_irq(&parent->power.lock); + /* + * We can resume if the parent's run-time PM is disabled or it + * is set to ignore children. + */ + if (!parent->power.disable_depth + && !parent->power.ignore_children) { + __pm_runtime_resume(parent, false); + if (parent->power.runtime_status != RPM_ACTIVE) + retval = -EBUSY; + } + spin_unlock_irq(&parent->power.lock); + + spin_lock_irq(&dev->power.lock); + if (retval) + goto out; + goto repeat; + } + + dev->power.runtime_status = RPM_RESUMING; + + if (dev->bus && dev->bus->pm && dev->bus->pm->runtime_resume) { + spin_unlock_irq(&dev->power.lock); + + retval = dev->bus->pm->runtime_resume(dev); + + spin_lock_irq(&dev->power.lock); + dev->power.runtime_error = retval; + } else { + retval = -ENOSYS; + } + + if (retval) { + dev->power.runtime_status = RPM_SUSPENDED; + pm_runtime_cancel_pending(dev); + } else { + dev->power.runtime_status = RPM_ACTIVE; + if (parent) + atomic_inc(&parent->power.child_count); + } + wake_up_all(&dev->power.wait_queue); + + if (!retval) + __pm_request_idle(dev); + + out: + if (parent) { + spin_unlock_irq(&dev->power.lock); + + pm_runtime_put(parent); + |