From 3f9af0513ae5b1f185302c2d0ba656640926d970 Mon Sep 17 00:00:00 2001 From: Alan Stern Date: Sat, 25 Sep 2010 23:34:54 +0200 Subject: PM / Runtime: Replace boolean arguments with bitflags The "from_wq" argument in __pm_runtime_suspend() and __pm_runtime_resume() supposedly indicates whether or not the function was called by the PM workqueue thread, but in fact it isn't always used this way. It really indicates whether or not the function should return early if the requested operation is already in progress. Along with this badly-named boolean argument, later patches in this series will add several other boolean arguments to these functions and others. Therefore this patch (as1422) begins the conversion process by replacing from_wq with a bitflag argument. The same bitflags are also used in __pm_runtime_get() and __pm_runtime_put(), where they indicate whether or not the operation should be asynchronous. Signed-off-by: Alan Stern Signed-off-by: Rafael J. Wysocki --- include/linux/pm_runtime.h | 23 +++++++++++++++-------- 1 file changed, 15 insertions(+), 8 deletions(-) (limited to 'include/linux/pm_runtime.h') diff --git a/include/linux/pm_runtime.h b/include/linux/pm_runtime.h index 6e81888c6222..c030cac59aac 100644 --- a/include/linux/pm_runtime.h +++ b/include/linux/pm_runtime.h @@ -12,6 +12,11 @@ #include #include +/* Runtime PM flag argument bits */ +#define RPM_ASYNC 0x01 /* Request is asynchronous */ +#define RPM_NOWAIT 0x02 /* Don't wait for concurrent + state change */ + #ifdef CONFIG_PM_RUNTIME extern struct workqueue_struct *pm_wq; @@ -22,8 +27,8 @@ extern int pm_runtime_resume(struct device *dev); extern int pm_request_idle(struct device *dev); extern int pm_schedule_suspend(struct device *dev, unsigned int delay); extern int pm_request_resume(struct device *dev); -extern int __pm_runtime_get(struct device *dev, bool sync); -extern int __pm_runtime_put(struct device *dev, bool sync); +extern int __pm_runtime_get(struct device *dev, int rpmflags); +extern int __pm_runtime_put(struct device *dev, int rpmflags); extern int __pm_runtime_set_status(struct device *dev, unsigned int status); extern int pm_runtime_barrier(struct device *dev); extern void pm_runtime_enable(struct device *dev); @@ -81,8 +86,10 @@ static inline int pm_schedule_suspend(struct device *dev, unsigned int delay) return -ENOSYS; } static inline int pm_request_resume(struct device *dev) { return 0; } -static inline int __pm_runtime_get(struct device *dev, bool sync) { return 1; } -static inline int __pm_runtime_put(struct device *dev, bool sync) { return 0; } +static inline int __pm_runtime_get(struct device *dev, int rpmflags) + { return 1; } +static inline int __pm_runtime_put(struct device *dev, int rpmflags) + { return 0; } static inline int __pm_runtime_set_status(struct device *dev, unsigned int status) { return 0; } static inline int pm_runtime_barrier(struct device *dev) { return 0; } @@ -107,22 +114,22 @@ static inline int pm_generic_runtime_resume(struct device *dev) { return 0; } static inline int pm_runtime_get(struct device *dev) { - return __pm_runtime_get(dev, false); + return __pm_runtime_get(dev, RPM_ASYNC); } static inline int pm_runtime_get_sync(struct device *dev) { - return __pm_runtime_get(dev, true); + return __pm_runtime_get(dev, 0); } static inline int pm_runtime_put(struct device *dev) { - return __pm_runtime_put(dev, false); + return __pm_runtime_put(dev, RPM_ASYNC); } static inline int pm_runtime_put_sync(struct device *dev) { - return __pm_runtime_put(dev, true); + return __pm_runtime_put(dev, 0); } static inline int pm_runtime_set_active(struct device *dev) -- cgit v1.3-7-g2ca7 From 140a6c945211ee911dec776fafa52e03a7d7bb9a Mon Sep 17 00:00:00 2001 From: Alan Stern Date: Sat, 25 Sep 2010 23:35:07 +0200 Subject: PM / Runtime: Combine runtime PM entry points This patch (as1424) combines the various public entry points for the runtime PM routines into three simple functions: one for idle, one for suspend, and one for resume. A new bitflag specifies whether or not to increment or decrement the usage_count field. The new entry points are named __pm_runtime_idle, __pm_runtime_suspend, and __pm_runtime_resume, to reflect that they are trampolines. Simultaneously, the corresponding internal routines are renamed to rpm_idle, rpm_suspend, and rpm_resume. Signed-off-by: Alan Stern Signed-off-by: Rafael J. Wysocki --- drivers/base/power/runtime.c | 174 ++++++++++++++++--------------------------- include/linux/pm_runtime.h | 66 +++++++++++----- 2 files changed, 110 insertions(+), 130 deletions(-) (limited to 'include/linux/pm_runtime.h') diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c index d7b5d84c235c..ed227b7c1bb5 100644 --- a/drivers/base/power/runtime.c +++ b/drivers/base/power/runtime.c @@ -11,7 +11,7 @@ #include #include -static int __pm_runtime_resume(struct device *dev, int rpmflags); +static int rpm_resume(struct device *dev, int rpmflags); /** * update_pm_runtime_accounting - Update the time accounting of power states @@ -107,7 +107,7 @@ static int rpm_check_suspend_allowed(struct device *dev) /** - * __pm_runtime_idle - Notify device bus type if the device can be suspended. + * rpm_idle - Notify device bus type if the device can be suspended. * @dev: Device to notify the bus type about. * @rpmflags: Flag bits. * @@ -118,7 +118,7 @@ static int rpm_check_suspend_allowed(struct device *dev) * * This function must be called under dev->power.lock with interrupts disabled. */ -static int __pm_runtime_idle(struct device *dev, int rpmflags) +static int rpm_idle(struct device *dev, int rpmflags) __releases(&dev->power.lock) __acquires(&dev->power.lock) { int retval; @@ -189,23 +189,7 @@ static int __pm_runtime_idle(struct device *dev, int rpmflags) } /** - * 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, 0); - 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. + * rpm_suspend - Carry out run-time suspend of given device. * @dev: Device to suspend. * @rpmflags: Flag bits. * @@ -220,7 +204,7 @@ EXPORT_SYMBOL_GPL(pm_runtime_idle); * * This function must be called under dev->power.lock with interrupts disabled. */ -static int __pm_runtime_suspend(struct device *dev, int rpmflags) +static int rpm_suspend(struct device *dev, int rpmflags) __releases(&dev->power.lock) __acquires(&dev->power.lock) { struct device *parent = NULL; @@ -332,13 +316,13 @@ static int __pm_runtime_suspend(struct device *dev, int rpmflags) wake_up_all(&dev->power.wait_queue); if (dev->power.deferred_resume) { - __pm_runtime_resume(dev, 0); + rpm_resume(dev, 0); retval = -EAGAIN; goto out; } if (notify) - __pm_runtime_idle(dev, 0); + rpm_idle(dev, 0); if (parent && !parent->power.ignore_children) { spin_unlock_irq(&dev->power.lock); @@ -355,23 +339,7 @@ static int __pm_runtime_suspend(struct device *dev, int rpmflags) } /** - * 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, 0); - 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. + * rpm_resume - Carry out run-time resume of given device. * @dev: Device to resume. * @rpmflags: Flag bits. * @@ -387,7 +355,7 @@ EXPORT_SYMBOL_GPL(pm_runtime_suspend); * * This function must be called under dev->power.lock with interrupts disabled. */ -static int __pm_runtime_resume(struct device *dev, int rpmflags) +static int rpm_resume(struct device *dev, int rpmflags) __releases(&dev->power.lock) __acquires(&dev->power.lock) { struct device *parent = NULL; @@ -469,7 +437,7 @@ static int __pm_runtime_resume(struct device *dev, int rpmflags) */ if (!parent->power.disable_depth && !parent->power.ignore_children) { - __pm_runtime_resume(parent, 0); + rpm_resume(parent, 0); if (parent->power.runtime_status != RPM_ACTIVE) retval = -EBUSY; } @@ -521,7 +489,7 @@ static int __pm_runtime_resume(struct device *dev, int rpmflags) wake_up_all(&dev->power.wait_queue); if (!retval) - __pm_runtime_idle(dev, RPM_ASYNC); + rpm_idle(dev, RPM_ASYNC); out: if (parent) { @@ -537,22 +505,6 @@ static int __pm_runtime_resume(struct device *dev, int rpmflags) return retval; } -/** - * pm_runtime_resume - Carry out run-time resume of given device. - * @dev: Device to suspend. - */ -int pm_runtime_resume(struct device *dev) -{ - int retval; - - spin_lock_irq(&dev->power.lock); - retval = __pm_runtime_resume(dev, 0); - spin_unlock_irq(&dev->power.lock); - - return retval; -} -EXPORT_SYMBOL_GPL(pm_runtime_resume); - /** * pm_runtime_work - Universal run-time PM work function. * @work: Work structure used for scheduling the execution of this function. @@ -578,13 +530,13 @@ static void pm_runtime_work(struct work_struct *work) case RPM_REQ_NONE: break; case RPM_REQ_IDLE: - __pm_runtime_idle(dev, RPM_NOWAIT); + rpm_idle(dev, RPM_NOWAIT); break; case RPM_REQ_SUSPEND: - __pm_runtime_suspend(dev, RPM_NOWAIT); + rpm_suspend(dev, RPM_NOWAIT); break; case RPM_REQ_RESUME: - __pm_runtime_resume(dev, RPM_NOWAIT); + rpm_resume(dev, RPM_NOWAIT); break; } @@ -592,23 +544,6 @@ static void pm_runtime_work(struct work_struct *work) spin_unlock_irq(&dev->power.lock); } -/** - * pm_request_idle - Submit an idle notification request for given device. - * @dev: Device to handle. - */ -int pm_request_idle(struct device *dev) -{ - unsigned long flags; - int retval; - - spin_lock_irqsave(&dev->power.lock, flags); - retval = __pm_runtime_idle(dev, RPM_ASYNC); - spin_unlock_irqrestore(&dev->power.lock, flags); - - return retval; -} -EXPORT_SYMBOL_GPL(pm_request_idle); - /** * pm_suspend_timer_fn - Timer function for pm_schedule_suspend(). * @data: Device pointer passed by pm_schedule_suspend(). @@ -627,7 +562,7 @@ static void pm_suspend_timer_fn(unsigned long data) /* If 'expire' is after 'jiffies' we've been called too early. */ if (expires > 0 && !time_after(expires, jiffies)) { dev->power.timer_expires = 0; - __pm_runtime_suspend(dev, RPM_ASYNC); + rpm_suspend(dev, RPM_ASYNC); } spin_unlock_irqrestore(&dev->power.lock, flags); @@ -646,7 +581,7 @@ int pm_schedule_suspend(struct device *dev, unsigned int delay) spin_lock_irqsave(&dev->power.lock, flags); if (!delay) { - retval = __pm_runtime_suspend(dev, RPM_ASYNC); + retval = rpm_suspend(dev, RPM_ASYNC); goto out; } @@ -669,62 +604,81 @@ int pm_schedule_suspend(struct device *dev, unsigned int delay) EXPORT_SYMBOL_GPL(pm_schedule_suspend); /** - * pm_request_resume - Submit a resume request for given device. - * @dev: Device to resume. + * __pm_runtime_idle - Entry point for run-time 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. */ -int pm_request_resume(struct device *dev) +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; + } + spin_lock_irqsave(&dev->power.lock, flags); - retval = __pm_runtime_resume(dev, RPM_ASYNC); + retval = rpm_idle(dev, rpmflags); spin_unlock_irqrestore(&dev->power.lock, flags); return retval; } -EXPORT_SYMBOL_GPL(pm_request_resume); +EXPORT_SYMBOL_GPL(__pm_runtime_idle); /** - * __pm_runtime_get - Reference count a device and wake it up, if necessary. - * @dev: Device to handle. + * __pm_runtime_suspend - Entry point for run-time put/suspend operations. + * @dev: Device to suspend. * @rpmflags: Flag bits. * - * Increment the usage count of the device and resume it or submit a resume - * request for it, depending on the RPM_ASYNC flag bit. + * Carry out a suspend, either synchronous or asynchronous. + * + * This routine may be called in atomic context if the RPM_ASYNC flag is set. */ -int __pm_runtime_get(struct device *dev, int rpmflags) +int __pm_runtime_suspend(struct device *dev, int rpmflags) { + unsigned long flags; int retval; - atomic_inc(&dev->power.usage_count); - retval = (rpmflags & RPM_ASYNC) ? - pm_request_resume(dev) : pm_runtime_resume(dev); + 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_get); +EXPORT_SYMBOL_GPL(__pm_runtime_suspend); /** - * __pm_runtime_put - Decrement the device's usage counter and notify its bus. - * @dev: Device to handle. + * __pm_runtime_resume - Entry point for run-time resume operations. + * @dev: Device to resume. * @rpmflags: Flag bits. * - * Decrement the usage count of the device and if it reaches zero, carry out a - * synchronous idle notification or submit an idle notification request for it, - * depending on the RPM_ASYNC flag bit. + * 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. */ -int __pm_runtime_put(struct device *dev, int rpmflags) +int __pm_runtime_resume(struct device *dev, int rpmflags) { - int retval = 0; + unsigned long flags; + int retval; - if (atomic_dec_and_test(&dev->power.usage_count)) - retval = (rpmflags & RPM_ASYNC) ? - pm_request_idle(dev) : pm_runtime_idle(dev); + 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_put); +EXPORT_SYMBOL_GPL(__pm_runtime_resume); /** * __pm_runtime_set_status - Set run-time PM status of a device. @@ -875,7 +829,7 @@ int pm_runtime_barrier(struct device *dev) if (dev->power.request_pending && dev->power.request == RPM_REQ_RESUME) { - __pm_runtime_resume(dev, 0); + rpm_resume(dev, 0); retval = 1; } @@ -924,7 +878,7 @@ void __pm_runtime_disable(struct device *dev, bool check_resume) */ pm_runtime_get_noresume(dev); - __pm_runtime_resume(dev, 0); + rpm_resume(dev, 0); pm_runtime_put_noidle(dev); } @@ -972,7 +926,7 @@ void pm_runtime_forbid(struct device *dev) dev->power.runtime_auto = false; atomic_inc(&dev->power.usage_count); - __pm_runtime_resume(dev, 0); + rpm_resume(dev, 0); out: spin_unlock_irq(&dev->power.lock); @@ -993,7 +947,7 @@ void pm_runtime_allow(struct device *dev) dev->power.runtime_auto = true; if (atomic_dec_and_test(&dev->power.usage_count)) - __pm_runtime_idle(dev, 0); + rpm_idle(dev, 0); out: spin_unlock_irq(&dev->power.lock); diff --git a/include/linux/pm_runtime.h b/include/linux/pm_runtime.h index c030cac59aac..5869d87fffac 100644 --- a/include/linux/pm_runtime.h +++ b/include/linux/pm_runtime.h @@ -16,19 +16,17 @@ #define RPM_ASYNC 0x01 /* Request is asynchronous */ #define RPM_NOWAIT 0x02 /* Don't wait for concurrent state change */ +#define RPM_GET_PUT 0x04 /* Increment/decrement the + usage_count */ #ifdef CONFIG_PM_RUNTIME extern struct workqueue_struct *pm_wq; -extern int pm_runtime_idle(struct device *dev); -extern int pm_runtime_suspend(struct device *dev); -extern int pm_runtime_resume(struct device *dev); -extern int pm_request_idle(struct device *dev); +extern int __pm_runtime_idle(struct device *dev, int rpmflags); +extern int __pm_runtime_suspend(struct device *dev, int rpmflags); +extern int __pm_runtime_resume(struct device *dev, int rpmflags); extern int pm_schedule_suspend(struct device *dev, unsigned int delay); -extern int pm_request_resume(struct device *dev); -extern int __pm_runtime_get(struct device *dev, int rpmflags); -extern int __pm_runtime_put(struct device *dev, int rpmflags); extern int __pm_runtime_set_status(struct device *dev, unsigned int status); extern int pm_runtime_barrier(struct device *dev); extern void pm_runtime_enable(struct device *dev); @@ -77,19 +75,22 @@ static inline bool pm_runtime_suspended(struct device *dev) #else /* !CONFIG_PM_RUNTIME */ -static inline int pm_runtime_idle(struct device *dev) { return -ENOSYS; } -static inline int pm_runtime_suspend(struct device *dev) { return -ENOSYS; } -static inline int pm_runtime_resume(struct device *dev) { return 0; } -static inline int pm_request_idle(struct device *dev) { return -ENOSYS; } +static inline int __pm_runtime_idle(struct device *dev, int rpmflags) +{ + return -ENOSYS; +} +static inline int __pm_runtime_suspend(struct device *dev, int rpmflags) +{ + return -ENOSYS; +} +static inline int __pm_runtime_resume(struct device *dev, int rpmflags) +{ + return 1; +} static inline int pm_schedule_suspend(struct device *dev, unsigned int delay) { return -ENOSYS; } -static inline int pm_request_resume(struct device *dev) { return 0; } -static inline int __pm_runtime_get(struct device *dev, int rpmflags) - { return 1; } -static inline int __pm_runtime_put(struct device *dev, int rpmflags) - { return 0; } static inline int __pm_runtime_set_status(struct device *dev, unsigned int status) { return 0; } static inline int pm_runtime_barrier(struct device *dev) { return 0; } @@ -112,24 +113,49 @@ static inline int pm_generic_runtime_resume(struct device *dev) { return 0; } #endif /* !CONFIG_PM_RUNTIME */ +static inline int pm_runtime_idle(struct device *dev) +{ + return __pm_runtime_idle(dev, 0); +} + +static inline int pm_runtime_suspend(struct device *dev) +{ + return __pm_runtime_suspend(dev, 0); +} + +static inline int pm_runtime_resume(struct device *dev) +{ + return __pm_runtime_resume(dev, 0); +} + +static inline int pm_request_idle(struct device *dev) +{ + return __pm_runtime_idle(dev, RPM_ASYNC); +} + +static inline int pm_request_resume(struct device *dev) +{ + return __pm_runtime_resume(dev, RPM_ASYNC); +} + static inline int pm_runtime_get(struct device *dev) { - return __pm_runtime_get(dev, RPM_ASYNC); + return __pm_runtime_resume(dev, RPM_GET_PUT | RPM_ASYNC); } static inline int pm_runtime_get_sync(struct device *dev) { - return __pm_runtime_get(dev, 0); + return __pm_runtime_resume(dev, RPM_GET_PUT); } static inline int pm_runtime_put(struct device *dev) { - return __pm_runtime_put(dev, RPM_ASYNC); + return __pm_runtime_idle(dev, RPM_GET_PUT | RPM_ASYNC); } static inline int pm_runtime_put_sync(struct device *dev) { - return __pm_runtime_put(dev, 0); + return __pm_runtime_idle(dev, RPM_GET_PUT); } static inline int pm_runtime_set_active(struct device *dev) -- cgit v1.3-7-g2ca7 From 7490e44239e60293bca0c2663229050c36c660c2 Mon Sep 17 00:00:00 2001 From: Alan Stern Date: Sat, 25 Sep 2010 23:35:15 +0200 Subject: PM / Runtime: Add no_callbacks flag Some devices, such as USB interfaces, cannot be power-managed independently of their parents, i.e., they cannot be put in low power while the parent remains at full power. This patch (as1425) creates a new "no_callbacks" flag, which tells the PM core not to invoke the runtime-PM callback routines for the such devices but instead to assume that the callbacks always succeed. In addition, the non-debugging runtime-PM sysfs attributes for the devices are removed, since they are pretty much meaningless. The advantage of this scheme comes not so much from avoiding the callbacks themselves, but rather from the fact that without the need for a process context in which to run the callbacks, more work can be done in interrupt context. Signed-off-by: Alan Stern Signed-off-by: Rafael J. Wysocki --- Documentation/power/runtime_pm.txt | 37 +++++++++++++++++++++++++ drivers/base/power/power.h | 1 + drivers/base/power/runtime.c | 54 +++++++++++++++++++++++++++++++++++- drivers/base/power/sysfs.c | 56 +++++++++++++++++++++++++++++++++----- include/linux/pm.h | 7 +++++ include/linux/pm_runtime.h | 2 ++ 6 files changed, 149 insertions(+), 8 deletions(-) (limited to 'include/linux/pm_runtime.h') diff --git a/Documentation/power/runtime_pm.txt b/Documentation/power/runtime_pm.txt index 55b859b3bc72..9ba49b21ac86 100644 --- a/Documentation/power/runtime_pm.txt +++ b/Documentation/power/runtime_pm.txt @@ -1,6 +1,7 @@ Run-time Power Management Framework for I/O Devices (C) 2009 Rafael J. Wysocki , Novell Inc. +(C) 2010 Alan Stern 1. Introduction @@ -230,6 +231,11 @@ defined in include/linux/pm.h: interface; it may only be modified with the help of the pm_runtime_allow() and pm_runtime_forbid() helper functions + unsigned int no_callbacks; + - indicates that the device does not use the run-time PM callbacks (see + Section 8); it may be modified only by the pm_runtime_no_callbacks() + helper function + All of the above fields are members of the 'power' member of 'struct device'. 4. Run-time PM Device Helper Functions @@ -349,6 +355,11 @@ drivers/base/power/runtime.c and include/linux/pm_runtime.h: counter (used by the /sys/devices/.../power/control interface to effectively prevent the device from being power managed at run time) + void pm_runtime_no_callbacks(struct device *dev); + - set the power.no_callbacks flag for the device and remove the run-time + PM attributes from /sys/devices/.../power (or prevent them from being + added when the device is registered) + It is safe to execute the following helper functions from interrupt context: pm_request_idle() @@ -524,3 +535,29 @@ poweroff and run-time suspend callback, and similarly for system resume, thaw, restore, and run-time resume, can achieve this with the help of the UNIVERSAL_DEV_PM_OPS macro defined in include/linux/pm.h (possibly setting its last argument to NULL). + +8. "No-Callback" Devices + +Some "devices" are only logical sub-devices of their parent and cannot be +power-managed on their own. (The prototype example is a USB interface. Entire +USB devices can go into low-power mode or send wake-up requests, but neither is +possible for individual interfaces.) The drivers for these devices have no +need of run-time PM callbacks; if the callbacks did exist, ->runtime_suspend() +and ->runtime_resume() would always return 0 without doing anything else and +->runtime_idle() would always call pm_runtime_suspend(). + +Subsystems can tell the PM core about these devices by calling +pm_runtime_no_callbacks(). This should be done after the device structure is +initialized and before it is registered (although after device registration is +also okay). The routine will set the device's power.no_callbacks flag and +prevent the non-debugging run-time PM sysfs attributes from being created. + +When power.no_callbacks is set, the PM core will not invoke the +->runtime_idle(), ->runtime_suspend(), or ->runtime_resume() callbacks. +Instead it will assume that suspends and resumes always succeed and that idle +devices should be suspended. + +As a consequence, the PM core will never directly inform the device's subsystem +or driver about run-time power changes. Instead, the driver for the device's +parent must take responsibility for telling the device's driver when the +parent's power state changes. diff --git a/drivers/base/power/power.h b/drivers/base/power/power.h index 8b2745c69e2a..698dde742587 100644 --- a/drivers/base/power/power.h +++ b/drivers/base/power/power.h @@ -60,6 +60,7 @@ static inline void device_pm_move_last(struct device *dev) {} extern int dpm_sysfs_add(struct device *); extern void dpm_sysfs_remove(struct device *); +extern void rpm_sysfs_remove(struct device *); #else /* CONFIG_PM */ diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c index ed227b7c1bb5..5bd4daa93ef1 100644 --- a/drivers/base/power/runtime.c +++ b/drivers/base/power/runtime.c @@ -10,8 +10,10 @@ #include #include #include +#include "power.h" 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 @@ -148,6 +150,12 @@ static int rpm_idle(struct device *dev, int rpmflags) /* Pending requests need to be canceled. */ dev->power.request = RPM_REQ_NONE; + if (dev->power.no_callbacks) { + /* Assume ->runtime_idle() callback would have suspended. */ + retval = rpm_suspend(dev, rpmflags); + goto out; + } + /* Carry out an asynchronous or a synchronous idle notification. */ if (rpmflags & RPM_ASYNC) { dev->power.request = RPM_REQ_IDLE; @@ -254,6 +262,10 @@ static int rpm_suspend(struct device *dev, int rpmflags) goto repeat; } + dev->power.deferred_resume = false; + 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 = RPM_REQ_SUSPEND; @@ -265,7 +277,6 @@ static int rpm_suspend(struct device *dev, int rpmflags) } __update_runtime_status(dev, RPM_SUSPENDING); - dev->power.deferred_resume = false; if (dev->bus && dev->bus->pm && dev->bus->pm->runtime_suspend) { spin_unlock_irq(&dev->power.lock); @@ -305,6 +316,7 @@ static int rpm_suspend(struct device *dev, int rpmflags) pm_runtime_cancel_pending(dev); } } else { + no_callback: __update_runtime_status(dev, RPM_SUSPENDED); pm_runtime_deactivate_timer(dev); @@ -409,6 +421,23 @@ static int rpm_resume(struct device *dev, int rpmflags) 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(&dev->parent->power.lock); + 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); + 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; @@ -449,6 +478,9 @@ static int rpm_resume(struct device *dev, int rpmflags) goto repeat; } + if (dev->power.no_callbacks) + goto no_callback; /* Assume success. */ + __update_runtime_status(dev, RPM_RESUMING); if (dev->bus && dev->bus->pm && dev->bus->pm->runtime_resume) { @@ -482,6 +514,7 @@ static int rpm_resume(struct device *dev, int rpmflags) __update_runtime_status(dev, RPM_SUSPENDED); pm_runtime_cancel_pending(dev); } else { + no_callback: __update_runtime_status(dev, RPM_ACTIVE); if (parent) atomic_inc(&parent->power.child_count); @@ -954,6 +987,25 @@ void pm_runtime_allow(struct device *dev) } EXPORT_SYMBOL_GPL(pm_runtime_allow); +/** + * pm_runtime_no_callbacks - Ignore run-time 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 run-time PM + * callbacks of its own. The run-time 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_init - Initialize run-time PM fields in given device object. * @dev: Device object to initialize. diff --git a/drivers/base/power/sysfs.c b/drivers/base/power/sysfs.c index 8859780817e1..b5708c47ce2d 100644 --- a/drivers/base/power/sysfs.c +++ b/drivers/base/power/sysfs.c @@ -81,6 +81,9 @@ static const char enabled[] = "enabled"; static const char disabled[] = "disabled"; +const char power_group_name[] = "power"; +EXPORT_SYMBOL_GPL(power_group_name); + #ifdef CONFIG_PM_RUNTIME static const char ctrl_auto[] = "auto"; static const char ctrl_on[] = "on"; @@ -390,12 +393,6 @@ static DEVICE_ATTR(async, 0644, async_show, async_store); #endif /* CONFIG_PM_ADVANCED_DEBUG */ static struct attribute * power_attrs[] = { -#ifdef CONFIG_PM_RUNTIME - &dev_attr_control.attr, - &dev_attr_runtime_status.attr, - &dev_attr_runtime_suspended_time.attr, - &dev_attr_runtime_active_time.attr, -#endif &dev_attr_wakeup.attr, #ifdef CONFIG_PM_SLEEP &dev_attr_wakeup_count.attr, @@ -409,6 +406,7 @@ static struct attribute * power_attrs[] = { #ifdef CONFIG_PM_ADVANCED_DEBUG &dev_attr_async.attr, #ifdef CONFIG_PM_RUNTIME + &dev_attr_runtime_status.attr, &dev_attr_runtime_usage.attr, &dev_attr_runtime_active_kids.attr, &dev_attr_runtime_enabled.attr, @@ -417,10 +415,52 @@ static struct attribute * power_attrs[] = { NULL, }; static struct attribute_group pm_attr_group = { - .name = "power", + .name = power_group_name, .attrs = power_attrs, }; +#ifdef CONFIG_PM_RUNTIME + +static struct attribute *runtime_attrs[] = { +#ifndef CONFIG_PM_ADVANCED_DEBUG + &dev_attr_runtime_status.attr, +#endif + &dev_attr_control.attr, + &dev_attr_runtime_suspended_time.attr, + &dev_attr_runtime_active_time.attr, + NULL, +}; +static struct attribute_group pm_runtime_attr_group = { + .name = power_group_name, + .attrs = runtime_attrs, +}; + +int dpm_sysfs_add(struct device *dev) +{ + int rc; + + rc = sysfs_create_group(&dev->kobj, &pm_attr_group); + if (rc == 0 && !dev->power.no_callbacks) { + rc = sysfs_merge_group(&dev->kobj, &pm_runtime_attr_group); + if (rc) + sysfs_remove_group(&dev->kobj, &pm_attr_group); + } + return rc; +} + +void rpm_sysfs_remove(struct device *dev) +{ + sysfs_unmerge_group(&dev->kobj, &pm_runtime_attr_group); +} + +void dpm_sysfs_remove(struct device *dev) +{ + rpm_sysfs_remove(dev); + sysfs_remove_group(&dev->kobj, &pm_attr_group); +} + +#else /* CONFIG_PM_RUNTIME */ + int dpm_sysfs_add(struct device * dev) { return sysfs_create_group(&dev->kobj, &pm_attr_group); @@ -430,3 +470,5 @@ void dpm_sysfs_remove(struct device * dev) { sysfs_remove_group(&dev->kobj, &pm_attr_group); } + +#endif diff --git a/include/linux/pm.h b/include/linux/pm.h index 1abfe84f447d..abd81ffaba3c 100644 --- a/include/linux/pm.h +++ b/include/linux/pm.h @@ -41,6 +41,12 @@ extern void (*pm_power_off_prepare)(void); struct device; +#ifdef CONFIG_PM +extern const char power_group_name[]; /* = "power" */ +#else +#define power_group_name NULL +#endif + typedef struct pm_message { int event; } pm_message_t; @@ -475,6 +481,7 @@ struct dev_pm_info { unsigned int deferred_resume:1; unsigned int run_wake:1; unsigned int runtime_auto:1; + unsigned int no_callbacks:1; enum rpm_request request; enum rpm_status runtime_status; int runtime_error; diff --git a/include/linux/pm_runtime.h b/include/linux/pm_runtime.h index 5869d87fffac..8ca52f7c357e 100644 --- a/include/linux/pm_runtime.h +++ b/include/linux/pm_runtime.h @@ -36,6 +36,7 @@ extern void pm_runtime_forbid(struct device *dev); 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); static inline bool pm_children_suspended(struct device *dev) { @@ -110,6 +111,7 @@ static inline bool pm_runtime_suspended(struct device *dev) { return false; } 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) {} #endif /* !CONFIG_PM_RUNTIME */ -- cgit v1.3-7-g2ca7 From 15bcb91d7e607d8a2e060f01f7784a7454668da4 Mon Sep 17 00:00:00 2001 From: Alan Stern Date: Sat, 25 Sep 2010 23:35:21 +0200 Subject: PM / Runtime: Implement autosuspend support This patch (as1427) implements the "autosuspend" facility for runtime PM. A few new fields are added to the dev_pm_info structure and several new PM helper functions are defined, for telling the PM core whether or not a device uses autosuspend, for setting the autosuspend delay, and for marking periods of device activity. Drivers that do not want to use autosuspend can continue using the same helper functions as before; their behavior will not change. In addition, drivers supporting autosuspend can also call the old helper functions to get the old behavior. The details are all explained in Documentation/power/runtime_pm.txt and Documentation/ABI/testing/sysfs-devices-power. Signed-off-by: Alan Stern Signed-off-by: Rafael J. Wysocki --- Documentation/ABI/testing/sysfs-devices-power | 18 +++ Documentation/power/runtime_pm.txt | 190 +++++++++++++++++++++++++- drivers/base/power/runtime.c | 186 ++++++++++++++++++++++++- drivers/base/power/sysfs.c | 40 ++++++ include/linux/pm.h | 8 ++ include/linux/pm_runtime.h | 45 ++++++ 6 files changed, 473 insertions(+), 14 deletions(-) (limited to 'include/linux/pm_runtime.h') diff --git a/Documentation/ABI/testing/sysfs-devices-power b/Documentation/ABI/testing/sysfs-devices-power index 6bb2dd3c3a71..7628cd1bc36a 100644 --- a/Documentation/ABI/testing/sysfs-devices-power +++ b/Documentation/ABI/testing/sysfs-devices-power @@ -147,3 +147,21 @@ Description: milliseconds. This attribute is read-only. If the device is not enabled to wake up the system from sleep states, this attribute is empty. + +What: /sys/devices/.../power/autosuspend_delay_ms +Date: September 2010 +Contact: Alan Stern +Description: + The /sys/devices/.../power/autosuspend_delay_ms attribute + contains the autosuspend delay value (in milliseconds). Some + drivers do not want their device to suspend as soon as it + becomes idle at run time; they want the device to remain + inactive for a certain minimum period of time first. That + period is called the autosuspend delay. Negative values will + prevent the device from being suspended at run time (similar + to writing "on" to the power/control attribute). Values >= + 1000 will cause the autosuspend timer expiration to be rounded + up to the nearest second. + + Not all drivers support this attribute. If it isn't supported, + attempts to read or write it will yield I/O errors. diff --git a/Documentation/power/runtime_pm.txt b/Documentation/power/runtime_pm.txt index 9ba49b21ac86..489e9bacd165 100644 --- a/Documentation/power/runtime_pm.txt +++ b/Documentation/power/runtime_pm.txt @@ -158,7 +158,8 @@ rules: 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. + scheduled requests to execute the other callbacks for the same device, + except for scheduled autosuspends. 3. Run-time PM Device Fields @@ -166,7 +167,7 @@ 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 + - timer used for scheduling (delayed) suspend and autosuspend requests unsigned long timer_expires; - timer expiration time, in jiffies (if this is different from zero, the @@ -236,6 +237,23 @@ defined in include/linux/pm.h: Section 8); it may be modified only by the pm_runtime_no_callbacks() helper function + unsigned int use_autosuspend; + - indicates that the device's driver supports delayed autosuspend (see + Section 9); it may be modified only by the + pm_runtime{_dont}_use_autosuspend() helper functions + + unsigned int timer_autosuspends; + - indicates that the PM core should attempt to carry out an autosuspend + when the timer expires rather than a normal suspend + + int autosuspend_delay; + - the delay time (in milliseconds) to be used for autosuspend + + unsigned long last_busy; + - the time (in jiffies) when the pm_runtime_mark_last_busy() helper + function was last called for this device; used in calculating inactivity + periods for autosuspend + All of the above fields are members of the 'power' member of 'struct device'. 4. Run-time PM Device Helper Functions @@ -261,6 +279,12 @@ drivers/base/power/runtime.c and include/linux/pm_runtime.h: error code on failure, where -EAGAIN or -EBUSY means it is safe to attempt to suspend the device again in future + int pm_runtime_autosuspend(struct device *dev); + - same as pm_runtime_suspend() except that the autosuspend delay is taken + into account; if pm_runtime_autosuspend_expiration() says the delay has + not yet expired then an autosuspend is scheduled for the appropriate time + and 0 is returned + int pm_runtime_resume(struct device *dev); - execute the subsystem-level resume callback for the device; returns 0 on success, 1 if the device's run-time PM status was already 'active' or @@ -273,6 +297,11 @@ drivers/base/power/runtime.c and include/linux/pm_runtime.h: device (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_request_autosuspend(struct device *dev); + - schedule the execution of the subsystem-level suspend callback for the + device when the autosuspend delay has expired; if the delay has already + expired then the work item is queued up immediately + int pm_schedule_suspend(struct device *dev, unsigned int delay); - schedule the execution of the subsystem-level suspend callback for the device in future, where 'delay' is the time to wait before queuing up a @@ -304,12 +333,20 @@ drivers/base/power/runtime.c and include/linux/pm_runtime.h: - 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 + - decrement the device's usage counter; if the result is 0 then run + pm_request_idle(dev) and return its result + + int pm_runtime_put_autosuspend(struct device *dev); + - decrement the device's usage counter; if the result is 0 then run + pm_request_autosuspend(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 + - 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_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 void pm_runtime_enable(struct device *dev); - enable the run-time PM helper functions to run the device bus type's @@ -360,19 +397,46 @@ 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_mark_last_busy(struct device *dev); + - set the power.last_busy field to the current time + + void pm_runtime_use_autosuspend(struct device *dev); + - set the power.use_autosuspend flag, enabling autosuspend delays + + void pm_runtime_dont_use_autosuspend(struct device *dev); + - clear the power.use_autosuspend flag, disabling autosuspend delays + + void pm_runtime_set_autosuspend_delay(struct device *dev, int delay); + - set the power.autosuspend_delay value to 'delay' (expressed in + milliseconds); if 'delay' is negative then run-time suspends are + prevented + + unsigned long pm_runtime_autosuspend_expiration(struct device *dev); + - calculate the time when the current autosuspend delay period will expire, + based on power.last_busy and power.autosuspend_delay; if the delay time + is 1000 ms or larger then the expiration time is rounded up to the + nearest second; returns 0 if the delay period has already expired or + power.use_autosuspend isn't set, otherwise returns the expiration time + in jiffies + It is safe to execute the following helper functions from interrupt context: pm_request_idle() +pm_request_autosuspend() pm_schedule_suspend() pm_request_resume() pm_runtime_get_noresume() pm_runtime_get() pm_runtime_put_noidle() pm_runtime_put() +pm_runtime_put_autosuspend() +pm_runtime_enable() pm_suspend_ignore_children() pm_runtime_set_active() pm_runtime_set_suspended() -pm_runtime_enable() +pm_runtime_suspended() +pm_runtime_mark_last_busy() +pm_runtime_autosuspend_expiration() 5. Run-time PM Initialization, Device Probing and Removal @@ -561,3 +625,115 @@ As a consequence, the PM core will never directly inform the device's subsystem or driver about run-time power changes. Instead, the driver for the device's parent must take responsibility for telling the device's driver when the parent's power state changes. + +9. Autosuspend, or automatically-delayed suspends + +Changing a device's power state isn't free; it requires both time and energy. +A device should be put in a low-power state only when there's some reason to +think it will remain in that state for a substantial time. A common heuristic +says that a device which hasn't been used for a while is liable to remain +unused; following this advice, drivers should not allow devices to be suspended +at run-time until they have been inactive for some minimum period. Even when +the heuristic ends up being non-optimal, it will still prevent devices from +"bouncing" too rapidly between low-power and full-power states. + +The term "autosuspend" is an historical remnant. It doesn't mean that the +device is automatically suspended (the subsystem or driver still has to call +the appropriate PM routines); rather it means that run-time suspends will +automatically be delayed until the desired period of inactivity has elapsed. + +Inactivity is determined based on the power.last_busy field. Drivers should +call pm_runtime_mark_last_busy() to update this field after carrying out I/O, +typically just before calling pm_runtime_put_autosuspend(). The desired length +of the inactivity period is a matter of policy. Subsystems can set this length +initially by calling pm_runtime_set_autosuspend_delay(), but after device +registration the length should be controlled by user space, using the +/sys/devices/.../power/autosuspend_delay_ms attribute. + +In order to use autosuspend, subsystems or drivers must call +pm_runtime_use_autosuspend() (preferably before registering the device), and +thereafter they should use the various *_autosuspend() helper functions instead +of the non-autosuspend counterparts: + + Instead of: pm_runtime_suspend use: pm_runtime_autosuspend; + Instead of: pm_schedule_suspend use: pm_request_autosuspend; + Instead of: pm_runtime_put use: pm_runtime_put_autosuspend; + Instead of: pm_runtime_put_sync use: pm_runtime_put_sync_autosuspend. + +Drivers may also continue to use the non-autosuspend helper functions; they +will behave normally, not taking the autosuspend delay into account. +Similarly, if the power.use_autosuspend field isn't set then the autosuspend +helper functions will behave just like the non-autosuspend counterparts. + +The implementation is well suited for asynchronous use in interrupt contexts. +However such use inevitably involves races, because the PM core can't +synchronize ->runtime_suspend() callbacks with the arrival of I/O requests. +This synchronization must be handled by the driver, using its private lock. +Here is a schematic pseudo-code example: + + foo_read_or_write(struct foo_priv *foo, void *data) + { + lock(&foo->private_lock); + add_request_to_io_queue(foo, data); + if (foo->num_pending_requests++ == 0) + pm_runtime_get(&foo->dev); + if (!foo->is_suspended) + foo_process_next_request(foo); + unlock(&foo->private_lock); + } + + foo_io_completion(struct foo_priv *foo, void *req) + { + lock(&foo->private_lock); + if (--foo->num_pending_requests == 0) { + pm_runtime_mark_last_busy(&foo->dev); + pm_runtime_put_autosuspend(&foo->dev); + } else { + foo_process_next_request(foo); + } + unlock(&foo->private_lock); + /* Send req result back to the user ... */ + } + + int foo_runtime_suspend(struct device *dev) + { + struct foo_priv foo = container_of(dev, ...); + int ret = 0; + + lock(&foo->private_lock); + if (foo->num_pending_requests > 0) { + ret = -EBUSY; + } else { + /* ... suspend the device ... */ + foo->is_suspended = 1; + } + unlock(&foo->private_lock); + return ret; + } + + int foo_runtime_resume(struct device *dev) + { + struct foo_priv foo = container_of(dev, ...); + + lock(&foo->private_lock); + /* ... resume the device ... */ + foo->is_suspended = 0; + pm_runtime_mark_last_busy(&foo->dev); + if (foo->num_pending_requests > 0) + foo_process_requests(foo); + unlock(&foo->private_lock); + return 0; + } + +The important point is that after foo_io_completion() asks for an autosuspend, +the foo_runtime_suspend() callback may race with foo_read_or_write(). +Therefore foo_runtime_suspend() has to check whether there are any pending I/O +requests (while holding the private lock) before allowing the suspend to +proceed. + +In addition, the power.autosuspend_delay field can be changed by user space at +any time. If a driver cares about this, it can call +pm_runtime_autosuspend_expiration() from within the ->runtime_suspend() +callback while holding its private lock. If the function returns a nonzero +value then the delay has not yet expired and the callback should return +-EAGAIN. diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c index 5bd4daa93ef1..cd4e100a1362 100644 --- a/drivers/base/power/runtime.c +++ b/drivers/base/power/runtime.c @@ -9,7 +9,6 @@ #include #include -#include #include "power.h" static int rpm_resume(struct device *dev, int rpmflags); @@ -79,6 +78,53 @@ static void pm_runtime_cancel_pending(struct device *dev) 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 = ACCESS_ONCE(dev->power.autosuspend_delay); + if (autosuspend_delay < 0) + goto out; + + last_busy = ACCESS_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); + /** * rpm_check_suspend_allowed - Test whether a device may be suspended. * @dev: Device to test. @@ -234,6 +280,32 @@ static int rpm_suspend(struct device *dev, int rpmflags) 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); @@ -268,7 +340,8 @@ static int rpm_suspend(struct device *dev, int rpmflags) /* Carry out an asynchronous or a synchronous suspend. */ if (rpmflags & RPM_ASYNC) { - dev->power.request = RPM_REQ_SUSPEND; + 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); @@ -383,8 +456,15 @@ static int rpm_resume(struct device *dev, int rpmflags) if (retval) goto out; - /* Other scheduled or pending requests need to be canceled. */ - pm_runtime_cancel_pending(dev); + /* + * 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; @@ -568,6 +648,9 @@ static void pm_runtime_work(struct work_struct *work) 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; @@ -595,7 +678,8 @@ static void pm_suspend_timer_fn(unsigned long data) /* 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, RPM_ASYNC); + rpm_suspend(dev, dev->power.timer_autosuspends ? + (RPM_ASYNC | RPM_AUTO) : RPM_ASYNC); } spin_unlock_irqrestore(&dev->power.lock, flags); @@ -627,6 +711,7 @@ int pm_schedule_suspend(struct device *dev, unsigned int delay) 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: @@ -670,7 +755,9 @@ EXPORT_SYMBOL_GPL(__pm_runtime_idle); * @dev: Device to suspend. * @rpmflags: Flag bits. * - * Carry out a suspend, either synchronous or asynchronous. + * 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. */ @@ -679,6 +766,11 @@ 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; + } + spin_lock_irqsave(&dev->power.lock, flags); retval = rpm_suspend(dev, rpmflags); spin_unlock_irqrestore(&dev->power.lock, flags); @@ -980,7 +1072,7 @@ void pm_runtime_allow(struct device *dev) dev->power.runtime_auto = true; if (atomic_dec_and_test(&dev->power.usage_count)) - rpm_idle(dev, 0); + rpm_idle(dev, RPM_AUTO); out: spin_unlock_irq(&dev->power.lock); @@ -1006,6 +1098,86 @@ void pm_runtime_no_callbacks(struct device *dev) } EXPORT_SYMBOL_GPL(pm_runtime_no_callbacks); +/** + * 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 run-time suspends. If it + * changes the other way, allow run-time 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 run-time + * 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 run-time PM fields in given device object. * @dev: Device object to initialize. diff --git a/drivers/base/power/sysfs.c b/drivers/base/power/sysfs.c index b5708c47ce2d..0b1e46bf3e56 100644 --- a/drivers/base/power/sysfs.c +++ b/drivers/base/power/sysfs.c @@ -75,6 +75,18 @@ * attribute is set to "enabled" by bus type code or device drivers and in * that cases it should be safe to leave the default value. * + * autosuspend_delay_ms - Report/change a device's autosuspend_delay value + * + * Some drivers don't want to carry out a runtime suspend as soon as a + * device becomes idle; they want it always to remain idle for some period + * of time before suspending it. This period is the autosuspend_delay + * value (expressed in milliseconds) and it can be controlled by the user. + * If the value is negative then the device will never be runtime + * suspended. + * + * NOTE: The autosuspend_delay_ms attribute and the autosuspend_delay + * value are used only if the driver calls pm_runtime_use_autosuspend(). + * * wakeup_count - Report the number of wakeup events related to the device */ @@ -173,6 +185,33 @@ static ssize_t rtpm_status_show(struct device *dev, } static DEVICE_ATTR(runtime_status, 0444, rtpm_status_show, NULL); + +static ssize_t autosuspend_delay_ms_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + if (!dev->power.use_autosuspend) + return -EIO; + return sprintf(buf, "%d\n", dev->power.autosuspend_delay); +} + +static ssize_t autosuspend_delay_ms_store(struct device *dev, + struct device_attribute *attr, const char *buf, size_t n) +{ + long delay; + + if (!dev->power.use_autosuspend) + return -EIO; + + if (strict_strtol(buf, 10, &delay) != 0 || delay != (int) delay) + return -EINVAL; + + pm_runtime_set_autosuspend_delay(dev, delay); + return n; +} + +static DEVICE_ATTR(autosuspend_delay_ms, 0644, autosuspend_delay_ms_show, + autosuspend_delay_ms_store); + #endif static ssize_t @@ -428,6 +467,7 @@ static struct attribute *runtime_attrs[] = { &dev_attr_control.attr, &dev_attr_runtime_suspended_time.attr, &dev_attr_runtime_active_time.attr, + &dev_attr_autosuspend_delay_ms.attr, NULL, }; static struct attribute_group pm_runtime_attr_group = { diff --git a/include/linux/pm.h b/include/linux/pm.h index abd81ffaba3c..40f3f45702ba 100644 --- a/include/linux/pm.h +++ b/include/linux/pm.h @@ -444,6 +444,9 @@ enum rpm_status { * * RPM_REQ_SUSPEND Run the device bus type's ->runtime_suspend() callback * + * RPM_REQ_AUTOSUSPEND Same as RPM_REQ_SUSPEND, but not until the device has + * been inactive for as long as power.autosuspend_delay + * * RPM_REQ_RESUME Run the device bus type's ->runtime_resume() callback */ @@ -451,6 +454,7 @@ enum rpm_request { RPM_REQ_NONE = 0, RPM_REQ_IDLE, RPM_REQ_SUSPEND, + RPM_REQ_AUTOSUSPEND, RPM_REQ_RESUME, }; @@ -482,9 +486,13 @@ struct dev_pm_info { unsigned int run_wake:1; unsigned int runtime_auto:1; unsigned int no_callbacks:1; + unsigned int use_autosuspend:1; + unsigned int timer_autosuspends:1; enum rpm_request request; enum rpm_status runtime_status; int runtime_error; + int autosuspend_delay; + unsigned long last_busy; unsigned long active_jiffies; unsigned long suspended_jiffies; unsigned long accounting_timestamp; diff --git a/include/linux/pm_runtime.h b/include/linux/pm_runtime.h index 8ca52f7c357e..99ed1aa8f933 100644 --- a/include/linux/pm_runtime.h +++ b/include/linux/pm_runtime.h @@ -12,12 +12,15 @@ #include #include +#include + /* Runtime PM flag argument bits */ #define RPM_ASYNC 0x01 /* Request is asynchronous */ #define RPM_NOWAIT 0x02 /* Don't wait for concurrent state change */ #define RPM_GET_PUT 0x04 /* Increment/decrement the usage_count */ +#define RPM_AUTO 0x08 /* Use autosuspend_delay */ #ifdef CONFIG_PM_RUNTIME @@ -37,6 +40,9 @@ 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_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); static inline bool pm_children_suspended(struct device *dev) { @@ -74,6 +80,11 @@ static inline bool pm_runtime_suspended(struct device *dev) return dev->power.runtime_status == RPM_SUSPENDED; } +static inline void pm_runtime_mark_last_busy(struct device *dev) +{ + ACCESS_ONCE(dev->power.last_busy) = jiffies; +} + #else /* !CONFIG_PM_RUNTIME */ static inline int __pm_runtime_idle(struct device *dev, int rpmflags) @@ -113,6 +124,14 @@ 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_mark_last_busy(struct device *dev) {} +static inline void __pm_runtime_use_autosuspend(struct device *dev, + bool use) {} +static inline void pm_runtime_set_autosuspend_delay(struct device *dev, + int delay) {} +static inline unsigned long pm_runtime_autosuspend_expiration( + struct device *dev) { return 0; } + #endif /* !CONFIG_PM_RUNTIME */ static inline int pm_runtime_idle(struct device *dev) @@ -125,6 +144,11 @@ static inline int pm_runtime_suspend(struct device *dev) return __pm_runtime_suspend(dev, 0); } +static inline int pm_runtime_autosuspend(struct device *dev) +{ + return __pm_runtime_suspend(dev, RPM_AUTO); +} + static inline int pm_runtime_resume(struct device *dev) { return __pm_runtime_resume(dev, 0); @@ -155,11 +179,22 @@ static inline int pm_runtime_put(struct device *dev) return __pm_runtime_idle(dev, RPM_GET_PUT | RPM_ASYNC); } +static inline int pm_runtime_put_autosuspend(struct device *dev) +{ + return __pm_runtime_suspend(dev, + RPM_GET_PUT | RPM_ASYNC | RPM_AUTO); +} + 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_autosuspend(struct device *dev) +{ + return __pm_runtime_suspend(dev, RPM_GET_PUT | RPM_AUTO); +} + static inline int pm_runtime_set_active(struct device *dev) { return __pm_runtime_set_status(dev, RPM_ACTIVE); @@ -175,4 +210,14 @@ static inline void pm_runtime_disable(struct device *dev) __pm_runtime_disable(dev, true); } +static inline void pm_runtime_use_autosuspend(struct device *dev) +{ + __pm_runtime_use_autosuspend(dev, true); +} + +static inline void pm_runtime_dont_use_autosuspend(struct device *dev) +{ + __pm_runtime_use_autosuspend(dev, false); +} + #endif -- cgit v1.3-7-g2ca7 From 5fc62aad4e7779c2f04691e48b351d08c050c1f1 Mon Sep 17 00:00:00 2001 From: Ming Lei Date: Wed, 29 Sep 2010 00:12:22 +0200 Subject: PM: runtime: add missed pm_request_autosuspend The patch "PM / Runtime: Implement autosuspend support" introduces "autosuspend" facility for runtime PM, but misses helper function of pm_request_autosuspend, so add it. Signed-off-by: Ming Lei Signed-off-by: Rafael J. Wysocki --- include/linux/pm_runtime.h | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'include/linux/pm_runtime.h') diff --git a/include/linux/pm_runtime.h b/include/linux/pm_runtime.h index 99ed1aa8f933..3ec2358f8692 100644 --- a/include/linux/pm_runtime.h +++ b/include/linux/pm_runtime.h @@ -164,6 +164,11 @@ static inline int pm_request_resume(struct device *dev) return __pm_runtime_resume(dev, RPM_ASYNC); } +static inline int pm_request_autosuspend(struct device *dev) +{ + return __pm_runtime_suspend(dev, RPM_ASYNC | RPM_AUTO); +} + static inline int pm_runtime_get(struct device *dev) { return __pm_runtime_resume(dev, RPM_GET_PUT | RPM_ASYNC); -- cgit v1.3-7-g2ca7 From f08f5a0add20834d3f3d876dfe08005a5df656db Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Thu, 16 Dec 2010 17:11:58 +0100 Subject: PM / Runtime: Fix pm_runtime_suspended() There are some situations (e.g. in __pm_generic_call()), where pm_runtime_suspended() is used to decide whether or not to execute a device's (system) ->suspend() callback. The callback is not executed if pm_runtime_suspended() returns true, but it does so for devices that don't even support runtime PM, because the power.disable_depth device field is ignored by it. This leads to problems (i.e. devices are not suspened when they should), so rework pm_runtime_suspended() so that it returns false if the device's power.disable_depth field is different from zero. Signed-off-by: Rafael J. Wysocki Cc: stable@kernel.org --- Documentation/power/runtime_pm.txt | 4 ++-- include/linux/pm_runtime.h | 3 ++- 2 files changed, 4 insertions(+), 3 deletions(-) (limited to 'include/linux/pm_runtime.h') diff --git a/Documentation/power/runtime_pm.txt b/Documentation/power/runtime_pm.txt index 489e9bacd165..41cc7b30d7dd 100644 --- a/Documentation/power/runtime_pm.txt +++ b/Documentation/power/runtime_pm.txt @@ -379,8 +379,8 @@ drivers/base/power/runtime.c and include/linux/pm_runtime.h: zero) bool pm_runtime_suspended(struct device *dev); - - return true if the device's runtime PM status is 'suspended', or false - otherwise + - return true if the device's runtime PM status is 'suspended' and its + 'power.disable_depth' field is equal to zero, or false otherwise void pm_runtime_allow(struct device *dev); - set the power.runtime_auto flag for the device and decrease its usage diff --git a/include/linux/pm_runtime.h b/include/linux/pm_runtime.h index 3ec2358f8692..d19f1cca7f74 100644 --- a/include/linux/pm_runtime.h +++ b/include/linux/pm_runtime.h @@ -77,7 +77,8 @@ static inline void device_set_run_wake(struct device *dev, bool enable) static inline bool pm_runtime_suspended(struct device *dev) { - return dev->power.runtime_status == RPM_SUSPENDED; + return dev->power.runtime_status == RPM_SUSPENDED + && !dev->power.disable_depth; } static inline void pm_runtime_mark_last_busy(struct device *dev) -- cgit v1.3-7-g2ca7