![Rafael J. Wysocki](/assets/img/avatar_default.png)
A runtime suspend of a device (e.g. an MMC controller) belonging to a power domain or, in a more complicated scenario, a runtime suspend of another device in the same power domain, may cause power to be removed from the entire domain. In that case, the amount of time necessary to runtime-resume the given device (e.g. the MMC controller) is often substantially greater than the time needed to run its driver's runtime resume callback. That may hurt performance in some situations, because user data may need to wait for the device to become operational, so we should make it possible to prevent that from happening. For this reason, introduce a new sysfs attribute for devices, power/pm_qos_resume_latency_us, allowing user space to specify the upper bound of the time necessary to bring the (runtime-suspended) device up after the resume of it has been requested. However, make that attribute appear only for the devices whose drivers declare support for it by calling the (new) dev_pm_qos_expose_latency_limit() helper function with the appropriate initial value of the attribute. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Reviewed-by: Kevin Hilman <khilman@ti.com> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Acked-by: Linus Walleij <linus.walleij@linaro.org>
88 lines
2.5 KiB
C
88 lines
2.5 KiB
C
#include <linux/pm_qos.h>
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#ifdef CONFIG_PM_RUNTIME
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extern void pm_runtime_init(struct device *dev);
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extern void pm_runtime_remove(struct device *dev);
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#else /* !CONFIG_PM_RUNTIME */
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static inline void pm_runtime_init(struct device *dev) {}
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static inline void pm_runtime_remove(struct device *dev) {}
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#endif /* !CONFIG_PM_RUNTIME */
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#ifdef CONFIG_PM_SLEEP
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/* kernel/power/main.c */
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extern int pm_async_enabled;
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/* drivers/base/power/main.c */
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extern struct list_head dpm_list; /* The active device list */
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static inline struct device *to_device(struct list_head *entry)
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{
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return container_of(entry, struct device, power.entry);
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}
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extern void device_pm_init(struct device *dev);
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extern void device_pm_add(struct device *);
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extern void device_pm_remove(struct device *);
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extern void device_pm_move_before(struct device *, struct device *);
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extern void device_pm_move_after(struct device *, struct device *);
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extern void device_pm_move_last(struct device *);
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#else /* !CONFIG_PM_SLEEP */
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static inline void device_pm_init(struct device *dev)
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{
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spin_lock_init(&dev->power.lock);
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dev->power.power_state = PMSG_INVALID;
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pm_runtime_init(dev);
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}
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static inline void device_pm_add(struct device *dev)
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{
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dev_pm_qos_constraints_init(dev);
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}
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static inline void device_pm_remove(struct device *dev)
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{
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dev_pm_qos_constraints_destroy(dev);
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pm_runtime_remove(dev);
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}
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static inline void device_pm_move_before(struct device *deva,
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struct device *devb) {}
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static inline void device_pm_move_after(struct device *deva,
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struct device *devb) {}
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static inline void device_pm_move_last(struct device *dev) {}
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#endif /* !CONFIG_PM_SLEEP */
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#ifdef CONFIG_PM
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/*
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* sysfs.c
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*/
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extern int dpm_sysfs_add(struct device *dev);
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extern void dpm_sysfs_remove(struct device *dev);
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extern void rpm_sysfs_remove(struct device *dev);
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extern int wakeup_sysfs_add(struct device *dev);
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extern void wakeup_sysfs_remove(struct device *dev);
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extern int pm_qos_sysfs_add(struct device *dev);
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extern void pm_qos_sysfs_remove(struct device *dev);
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#else /* CONFIG_PM */
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static inline int dpm_sysfs_add(struct device *dev) { return 0; }
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static inline void dpm_sysfs_remove(struct device *dev) {}
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static inline void rpm_sysfs_remove(struct device *dev) {}
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static inline int wakeup_sysfs_add(struct device *dev) { return 0; }
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static inline void wakeup_sysfs_remove(struct device *dev) {}
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static inline int pm_qos_sysfs_add(struct device *dev) { return 0; }
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static inline void pm_qos_sysfs_remove(struct device *dev) {}
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#endif
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