diff options
| -rw-r--r-- | Documentation/power/runtime_pm.txt | 37 | ||||
| -rw-r--r-- | drivers/base/power/power.h | 1 | ||||
| -rw-r--r-- | drivers/base/power/runtime.c | 54 | ||||
| -rw-r--r-- | drivers/base/power/sysfs.c | 56 | ||||
| -rw-r--r-- | include/linux/pm.h | 7 | ||||
| -rw-r--r-- | include/linux/pm_runtime.h | 2 |
6 files changed, 149 insertions, 8 deletions
diff --git a/Documentation/power/runtime_pm.txt b/Documentation/power/runtime_pm.txt index 55b859b3bc7..9ba49b21ac8 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 <rjw@sisk.pl>, Novell Inc. +(C) 2010 Alan Stern <stern@rowland.harvard.edu> 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 8b2745c69e2..698dde74258 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 ed227b7c1bb..5bd4daa93ef 100644 --- a/drivers/base/power/runtime.c +++ b/drivers/base/power/runtime.c @@ -10,8 +10,10 @@ #include <linux/sched.h> #include <linux/pm_runtime.h> #include <linux/jiffies.h> +#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); @@ -955,6 +988,25 @@ 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 8859780817e..b5708c47ce2 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 1abfe84f447..abd81ffaba3 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 5869d87fffa..8ca52f7c357 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 */ |