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![Rafael J. Wysocki](/assets/img/avatar_default.png)
Add a new latency tolerance device PM QoS type to be use for specifying active state (RPM_ACTIVE) memory access (DMA) latency tolerance requirements for devices. It may be used to prevent hardware from choosing overly aggressive energy-saving operation modes (causing too much latency to appear) for the whole platform. This feature reqiures hardware support, so it only will be available for devices having a new .set_latency_tolerance() callback in struct dev_pm_info populated, in which case the routine pointed to by it should implement whatever is necessary to transfer the effective requirement value to the hardware. Whenever the effective latency tolerance changes for the device, its .set_latency_tolerance() callback will be executed and the effective value will be passed to it. If that value is negative, which means that the list of latency tolerance requirements for the device is empty, the callback is expected to switch the underlying hardware latency tolerance control mechanism to an autonomous mode if available. If that value is PM_QOS_LATENCY_ANY, in turn, and the hardware supports a special "no requirement" setting, the callback is expected to use it. That allows software to prevent the hardware from automatically updating the device's latency tolerance in response to its power state changes (e.g. during transitions from D3cold to D0), which generally may be done in the autonomous latency tolerance control mode. If .set_latency_tolerance() is present for the device, a new pm_qos_latency_tolerance_us attribute will be present in the devivce's power directory in sysfs. Then, user space can use that attribute to specify its latency tolerance requirement for the device, if any. Writing "any" to it means "no requirement, but do not let the hardware control latency tolerance" and writing "auto" to it allows the hardware to be switched to the autonomous mode if there are no other requirements from the kernel side in the device's list. This changeset includes a fix from Mika Westerberg. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
235 lines
7.8 KiB
C
235 lines
7.8 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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#include <linux/workqueue.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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enum pm_qos_flags_status {
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PM_QOS_FLAGS_UNDEFINED = -1,
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PM_QOS_FLAGS_NONE,
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PM_QOS_FLAGS_SOME,
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PM_QOS_FLAGS_ALL,
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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_RESUME_LATENCY_DEFAULT_VALUE 0
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#define PM_QOS_LATENCY_TOLERANCE_DEFAULT_VALUE 0
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#define PM_QOS_LATENCY_TOLERANCE_NO_CONSTRAINT (-1)
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#define PM_QOS_LATENCY_ANY ((s32)(~(__u32)0 >> 1))
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#define PM_QOS_FLAG_NO_POWER_OFF (1 << 0)
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#define PM_QOS_FLAG_REMOTE_WAKEUP (1 << 1)
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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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struct delayed_work work; /* for pm_qos_update_request_timeout */
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};
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struct pm_qos_flags_request {
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struct list_head node;
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s32 flags; /* Do not change to 64 bit */
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};
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enum dev_pm_qos_req_type {
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DEV_PM_QOS_RESUME_LATENCY = 1,
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DEV_PM_QOS_LATENCY_TOLERANCE,
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DEV_PM_QOS_FLAGS,
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};
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struct dev_pm_qos_request {
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enum dev_pm_qos_req_type type;
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union {
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struct plist_node pnode;
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struct pm_qos_flags_request flr;
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} data;
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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 target_value
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* or effective_flags 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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s32 no_constraint_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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struct pm_qos_flags {
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struct list_head list;
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s32 effective_flags; /* Do not change to 64 bit */
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};
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struct dev_pm_qos {
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struct pm_qos_constraints resume_latency;
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struct pm_qos_constraints latency_tolerance;
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struct pm_qos_flags flags;
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struct dev_pm_qos_request *resume_latency_req;
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struct dev_pm_qos_request *latency_tolerance_req;
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struct dev_pm_qos_request *flags_req;
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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 != NULL;
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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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bool pm_qos_update_flags(struct pm_qos_flags *pqf,
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struct pm_qos_flags_request *req,
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enum pm_qos_req_action action, s32 val);
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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_update_request_timeout(struct pm_qos_request *req,
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s32 new_value, unsigned long timeout_us);
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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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enum pm_qos_flags_status __dev_pm_qos_flags(struct device *dev, s32 mask);
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enum pm_qos_flags_status dev_pm_qos_flags(struct device *dev, s32 mask);
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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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enum dev_pm_qos_req_type type, 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 enum pm_qos_flags_status __dev_pm_qos_flags(struct device *dev,
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s32 mask)
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{ return PM_QOS_FLAGS_UNDEFINED; }
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static inline enum pm_qos_flags_status dev_pm_qos_flags(struct device *dev,
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s32 mask)
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{ return PM_QOS_FLAGS_UNDEFINED; }
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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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enum dev_pm_qos_req_type type,
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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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int dev_pm_qos_expose_flags(struct device *dev, s32 value);
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void dev_pm_qos_hide_flags(struct device *dev);
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int dev_pm_qos_update_flags(struct device *dev, s32 mask, bool set);
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s32 dev_pm_qos_get_user_latency_tolerance(struct device *dev);
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int dev_pm_qos_update_user_latency_tolerance(struct device *dev, s32 val);
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static inline s32 dev_pm_qos_requested_resume_latency(struct device *dev)
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{
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return dev->power.qos->resume_latency_req->data.pnode.prio;
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}
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static inline s32 dev_pm_qos_requested_flags(struct device *dev)
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{
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return dev->power.qos->flags_req->data.flr.flags;
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}
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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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static inline int dev_pm_qos_expose_flags(struct device *dev, s32 value)
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{ return 0; }
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static inline void dev_pm_qos_hide_flags(struct device *dev) {}
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static inline int dev_pm_qos_update_flags(struct device *dev, s32 m, bool set)
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{ return 0; }
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static inline s32 dev_pm_qos_get_user_latency_tolerance(struct device *dev)
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{ return PM_QOS_LATENCY_TOLERANCE_NO_CONSTRAINT; }
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static inline int dev_pm_qos_update_user_latency_tolerance(struct device *dev, s32 val)
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{ return 0; }
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static inline s32 dev_pm_qos_requested_resume_latency(struct device *dev) { return 0; }
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static inline s32 dev_pm_qos_requested_flags(struct device *dev) { return 0; }
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#endif
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#endif
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