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85dc0b8a40
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>
149 lines
4.8 KiB
C
149 lines
4.8 KiB
C
#ifndef _LINUX_PM_QOS_H
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#define _LINUX_PM_QOS_H
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/* interface for the pm_qos_power infrastructure of the linux kernel.
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*
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* Mark Gross <mgross@linux.intel.com>
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*/
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#include <linux/plist.h>
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#include <linux/notifier.h>
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#include <linux/miscdevice.h>
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#include <linux/device.h>
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enum {
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PM_QOS_RESERVED = 0,
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PM_QOS_CPU_DMA_LATENCY,
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PM_QOS_NETWORK_LATENCY,
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PM_QOS_NETWORK_THROUGHPUT,
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/* insert new class ID */
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PM_QOS_NUM_CLASSES,
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};
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#define PM_QOS_DEFAULT_VALUE -1
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#define PM_QOS_CPU_DMA_LAT_DEFAULT_VALUE (2000 * USEC_PER_SEC)
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#define PM_QOS_NETWORK_LAT_DEFAULT_VALUE (2000 * USEC_PER_SEC)
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#define PM_QOS_NETWORK_THROUGHPUT_DEFAULT_VALUE 0
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#define PM_QOS_DEV_LAT_DEFAULT_VALUE 0
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struct pm_qos_request {
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struct plist_node node;
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int pm_qos_class;
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};
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struct dev_pm_qos_request {
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struct plist_node node;
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struct device *dev;
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};
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enum pm_qos_type {
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PM_QOS_UNITIALIZED,
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PM_QOS_MAX, /* return the largest value */
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PM_QOS_MIN /* return the smallest value */
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};
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/*
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* Note: The lockless read path depends on the CPU accessing
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* target_value atomically. Atomic access is only guaranteed on all CPU
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* types linux supports for 32 bit quantites
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*/
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struct pm_qos_constraints {
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struct plist_head list;
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s32 target_value; /* Do not change to 64 bit */
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s32 default_value;
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enum pm_qos_type type;
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struct blocking_notifier_head *notifiers;
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};
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/* Action requested to pm_qos_update_target */
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enum pm_qos_req_action {
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PM_QOS_ADD_REQ, /* Add a new request */
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PM_QOS_UPDATE_REQ, /* Update an existing request */
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PM_QOS_REMOVE_REQ /* Remove an existing request */
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};
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static inline int dev_pm_qos_request_active(struct dev_pm_qos_request *req)
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{
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return req->dev != 0;
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}
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int pm_qos_update_target(struct pm_qos_constraints *c, struct plist_node *node,
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enum pm_qos_req_action action, int value);
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void pm_qos_add_request(struct pm_qos_request *req, int pm_qos_class,
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s32 value);
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void pm_qos_update_request(struct pm_qos_request *req,
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s32 new_value);
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void pm_qos_remove_request(struct pm_qos_request *req);
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int pm_qos_request(int pm_qos_class);
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int pm_qos_add_notifier(int pm_qos_class, struct notifier_block *notifier);
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int pm_qos_remove_notifier(int pm_qos_class, struct notifier_block *notifier);
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int pm_qos_request_active(struct pm_qos_request *req);
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s32 pm_qos_read_value(struct pm_qos_constraints *c);
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#ifdef CONFIG_PM
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s32 __dev_pm_qos_read_value(struct device *dev);
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s32 dev_pm_qos_read_value(struct device *dev);
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int dev_pm_qos_add_request(struct device *dev, struct dev_pm_qos_request *req,
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s32 value);
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int dev_pm_qos_update_request(struct dev_pm_qos_request *req, s32 new_value);
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int dev_pm_qos_remove_request(struct dev_pm_qos_request *req);
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int dev_pm_qos_add_notifier(struct device *dev,
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struct notifier_block *notifier);
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int dev_pm_qos_remove_notifier(struct device *dev,
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struct notifier_block *notifier);
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int dev_pm_qos_add_global_notifier(struct notifier_block *notifier);
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int dev_pm_qos_remove_global_notifier(struct notifier_block *notifier);
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void dev_pm_qos_constraints_init(struct device *dev);
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void dev_pm_qos_constraints_destroy(struct device *dev);
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int dev_pm_qos_add_ancestor_request(struct device *dev,
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struct dev_pm_qos_request *req, s32 value);
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#else
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static inline s32 __dev_pm_qos_read_value(struct device *dev)
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{ return 0; }
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static inline s32 dev_pm_qos_read_value(struct device *dev)
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{ return 0; }
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static inline int dev_pm_qos_add_request(struct device *dev,
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struct dev_pm_qos_request *req,
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s32 value)
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{ return 0; }
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static inline int dev_pm_qos_update_request(struct dev_pm_qos_request *req,
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s32 new_value)
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{ return 0; }
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static inline int dev_pm_qos_remove_request(struct dev_pm_qos_request *req)
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{ return 0; }
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static inline int dev_pm_qos_add_notifier(struct device *dev,
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struct notifier_block *notifier)
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{ return 0; }
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static inline int dev_pm_qos_remove_notifier(struct device *dev,
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struct notifier_block *notifier)
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{ return 0; }
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static inline int dev_pm_qos_add_global_notifier(
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struct notifier_block *notifier)
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{ return 0; }
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static inline int dev_pm_qos_remove_global_notifier(
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struct notifier_block *notifier)
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{ return 0; }
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static inline void dev_pm_qos_constraints_init(struct device *dev)
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{
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dev->power.power_state = PMSG_ON;
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}
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static inline void dev_pm_qos_constraints_destroy(struct device *dev)
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{
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dev->power.power_state = PMSG_INVALID;
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}
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static inline int dev_pm_qos_add_ancestor_request(struct device *dev,
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struct dev_pm_qos_request *req, s32 value)
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{ return 0; }
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#endif
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#ifdef CONFIG_PM_RUNTIME
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int dev_pm_qos_expose_latency_limit(struct device *dev, s32 value);
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void dev_pm_qos_hide_latency_limit(struct device *dev);
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#else
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static inline int dev_pm_qos_expose_latency_limit(struct device *dev, s32 value)
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{ return 0; }
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static inline void dev_pm_qos_hide_latency_limit(struct device *dev) {}
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#endif
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#endif
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