diff options
| -rw-r--r-- | Documentation/power/runtime_pm.txt | 31 | ||||
| -rw-r--r-- | drivers/base/power/runtime.c | 47 | ||||
| -rw-r--r-- | include/linux/pm.h | 1 | ||||
| -rw-r--r-- | include/linux/pm_runtime.h | 7 |
4 files changed, 77 insertions, 9 deletions
diff --git a/Documentation/power/runtime_pm.txt b/Documentation/power/runtime_pm.txt index 41cc7b30d7dd..ffe55ffa540a 100644 --- a/Documentation/power/runtime_pm.txt +++ b/Documentation/power/runtime_pm.txt @@ -50,6 +50,15 @@ type's callbacks are not defined) of given device. The bus type, device type and device class callbacks are referred to as subsystem-level callbacks in what follows. +By default, the callbacks are always invoked in process context with interrupts +enabled. However, subsystems can use the pm_runtime_irq_safe() helper function +to tell the PM core that a device's ->runtime_suspend() and ->runtime_resume() +callbacks should be invoked in atomic context with interrupts disabled +(->runtime_idle() is still invoked the default way). This implies that these +callback routines must not block or sleep, but it also means that the +synchronous helper functions listed at the end of Section 4 can be used within +an interrupt handler or in an atomic context. + The subsystem-level suspend callback is _entirely_ _responsible_ for handling the suspend of the device as appropriate, which may, but need not include executing the device driver's own ->runtime_suspend() callback (from the @@ -237,6 +246,10 @@ defined in include/linux/pm.h: Section 8); it may be modified only by the pm_runtime_no_callbacks() helper function + unsigned int irq_safe; + - indicates that the ->runtime_suspend() and ->runtime_resume() callbacks + will be invoked with the spinlock held and interrupts disabled + unsigned int use_autosuspend; - indicates that the device's driver supports delayed autosuspend (see Section 9); it may be modified only by the @@ -344,6 +357,10 @@ drivers/base/power/runtime.c and include/linux/pm_runtime.h: - decrement the device's usage counter; if the result is 0 then run pm_runtime_idle(dev) and return its result + int pm_runtime_put_sync_suspend(struct device *dev); + - decrement the device's usage counter; if the result is 0 then run + pm_runtime_suspend(dev) and return its result + int pm_runtime_put_sync_autosuspend(struct device *dev); - decrement the device's usage counter; if the result is 0 then run pm_runtime_autosuspend(dev) and return its result @@ -397,6 +414,11 @@ drivers/base/power/runtime.c and include/linux/pm_runtime.h: PM attributes from /sys/devices/.../power (or prevent them from being added when the device is registered) + void pm_runtime_irq_safe(struct device *dev); + - set the power.irq_safe flag for the device, causing the runtime-PM + suspend and resume callbacks (but not the idle callback) to be invoked + with interrupts disabled + void pm_runtime_mark_last_busy(struct device *dev); - set the power.last_busy field to the current time @@ -438,6 +460,15 @@ pm_runtime_suspended() pm_runtime_mark_last_busy() pm_runtime_autosuspend_expiration() +If pm_runtime_irq_safe() has been called for a device then the following helper +functions may also be used in interrupt context: + +pm_runtime_suspend() +pm_runtime_autosuspend() +pm_runtime_resume() +pm_runtime_get_sync() +pm_runtime_put_sync_suspend() + 5. Run-time PM Initialization, Device Probing and Removal Initially, the run-time PM is disabled for all devices, which means that the diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c index 02c652be83e7..656493a5e073 100644 --- a/drivers/base/power/runtime.c +++ b/drivers/base/power/runtime.c @@ -250,13 +250,16 @@ static int rpm_callback(int (*cb)(struct device *), struct device *dev) if (!cb) return -ENOSYS; - spin_unlock_irq(&dev->power.lock); + if (dev->power.irq_safe) { + retval = cb(dev); + } else { + spin_unlock_irq(&dev->power.lock); - retval = cb(dev); + retval = cb(dev); - spin_lock_irq(&dev->power.lock); + spin_lock_irq(&dev->power.lock); + } dev->power.runtime_error = retval; - return retval; } @@ -404,7 +407,7 @@ static int rpm_suspend(struct device *dev, int rpmflags) goto out; } - if (parent && !parent->power.ignore_children) { + if (parent && !parent->power.ignore_children && !dev->power.irq_safe) { spin_unlock_irq(&dev->power.lock); pm_request_idle(parent); @@ -527,10 +530,13 @@ static int rpm_resume(struct device *dev, int rpmflags) if (!parent && dev->parent) { /* - * Increment the parent's resume counter and resume it if - * necessary. + * 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); @@ -553,6 +559,7 @@ static int rpm_resume(struct device *dev, int rpmflags) goto out; goto repeat; } + skip_parent: if (dev->power.no_callbacks) goto no_callback; /* Assume success. */ @@ -584,7 +591,7 @@ static int rpm_resume(struct device *dev, int rpmflags) rpm_idle(dev, RPM_ASYNC); out: - if (parent) { + if (parent && !dev->power.irq_safe) { spin_unlock_irq(&dev->power.lock); pm_runtime_put(parent); @@ -1065,7 +1072,6 @@ EXPORT_SYMBOL_GPL(pm_runtime_allow); * Set the power.no_callbacks flag, which tells the PM core that this * device is power-managed through its parent and has no run-time PM * callbacks of its own. The run-time sysfs attributes will be removed. - * */ void pm_runtime_no_callbacks(struct device *dev) { @@ -1078,6 +1084,27 @@ void pm_runtime_no_callbacks(struct device *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. @@ -1199,4 +1226,6 @@ void pm_runtime_remove(struct device *dev) /* Change the status back to 'suspended' to match the initial status. */ if (dev->power.runtime_status == RPM_ACTIVE) pm_runtime_set_suspended(dev); + if (dev->power.irq_safe && dev->parent) + pm_runtime_put_sync(dev->parent); } diff --git a/include/linux/pm.h b/include/linux/pm.h index 40f3f45702ba..61f2066e6852 100644 --- a/include/linux/pm.h +++ b/include/linux/pm.h @@ -486,6 +486,7 @@ struct dev_pm_info { unsigned int run_wake:1; unsigned int runtime_auto:1; unsigned int no_callbacks:1; + unsigned int irq_safe:1; unsigned int use_autosuspend:1; unsigned int timer_autosuspends:1; enum rpm_request request; diff --git a/include/linux/pm_runtime.h b/include/linux/pm_runtime.h index d19f1cca7f74..e9cc049ccb62 100644 --- a/include/linux/pm_runtime.h +++ b/include/linux/pm_runtime.h @@ -40,6 +40,7 @@ extern int pm_generic_runtime_idle(struct device *dev); extern int pm_generic_runtime_suspend(struct device *dev); extern int pm_generic_runtime_resume(struct device *dev); extern void pm_runtime_no_callbacks(struct device *dev); +extern void pm_runtime_irq_safe(struct device *dev); extern void __pm_runtime_use_autosuspend(struct device *dev, bool use); extern void pm_runtime_set_autosuspend_delay(struct device *dev, int delay); extern unsigned long pm_runtime_autosuspend_expiration(struct device *dev); @@ -124,6 +125,7 @@ static inline int pm_generic_runtime_idle(struct device *dev) { return 0; } static inline int pm_generic_runtime_suspend(struct device *dev) { return 0; } static inline int pm_generic_runtime_resume(struct device *dev) { return 0; } static inline void pm_runtime_no_callbacks(struct device *dev) {} +static inline void pm_runtime_irq_safe(struct device *dev) {} static inline void pm_runtime_mark_last_busy(struct device *dev) {} static inline void __pm_runtime_use_autosuspend(struct device *dev, @@ -196,6 +198,11 @@ static inline int pm_runtime_put_sync(struct device *dev) return __pm_runtime_idle(dev, RPM_GET_PUT); } +static inline int pm_runtime_put_sync_suspend(struct device *dev) +{ + return __pm_runtime_suspend(dev, RPM_GET_PUT); +} + static inline int pm_runtime_put_sync_autosuspend(struct device *dev) { return __pm_runtime_suspend(dev, RPM_GET_PUT | RPM_AUTO); |