cbc9ef0287
On some systems there are CPU cores located in the same power domains as I/O devices. Then, power can only be removed from the domain if all I/O devices in it are not in use and the CPU core is idle. Add preliminary support for that to the generic PM domains framework. First, the platform is expected to provide a cpuidle driver with one extra state designated for use with the generic PM domains code. This state should be initially disabled and its exit_latency value should be set to whatever time is needed to bring up the CPU core itself after restoring power to it, not including the domain's power on latency. Its .enter() callback should point to a procedure that will remove power from the domain containing the CPU core at the end of the CPU power transition. The remaining characteristics of the extra cpuidle state, referred to as the "domain" cpuidle state below, (e.g. power usage, target residency) should be populated in accordance with the properties of the hardware. Next, the platform should execute genpd_attach_cpuidle() on the PM domain containing the CPU core. That will cause the generic PM domains framework to treat that domain in a special way such that: * When all devices in the domain have been suspended and it is about to be turned off, the states of the devices will be saved, but power will not be removed from the domain. Instead, the "domain" cpuidle state will be enabled so that power can be removed from the domain when the CPU core is idle and the state has been chosen as the target by the cpuidle governor. * When the first I/O device in the domain is resumed and __pm_genpd_poweron(() is called for the first time after power has been removed from the domain, the "domain" cpuidle state will be disabled to avoid subsequent surprise power removals via cpuidle. The effective exit_latency value of the "domain" cpuidle state depends on the time needed to bring up the CPU core itself after restoring power to it as well as on the power on latency of the domain containing the CPU core. Thus the "domain" cpuidle state's exit_latency has to be recomputed every time the domain's power on latency is updated, which may happen every time power is restored to the domain, if the measured power on latency is greater than the latency stored in the corresponding generic_pm_domain structure. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Reviewed-by: Kevin Hilman <khilman@ti.com>
232 lines
6.4 KiB
C
232 lines
6.4 KiB
C
/*
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* cpuidle.h - a generic framework for CPU idle power management
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*
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* (C) 2007 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
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* Shaohua Li <shaohua.li@intel.com>
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* Adam Belay <abelay@novell.com>
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*
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* This code is licenced under the GPL.
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*/
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#ifndef _LINUX_CPUIDLE_H
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#define _LINUX_CPUIDLE_H
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#include <linux/percpu.h>
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#include <linux/list.h>
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#include <linux/kobject.h>
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#include <linux/completion.h>
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#include <linux/hrtimer.h>
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#define CPUIDLE_STATE_MAX 8
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#define CPUIDLE_NAME_LEN 16
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#define CPUIDLE_DESC_LEN 32
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struct module;
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struct cpuidle_device;
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struct cpuidle_driver;
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/****************************
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* CPUIDLE DEVICE INTERFACE *
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****************************/
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struct cpuidle_state_usage {
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void *driver_data;
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unsigned long long disable;
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unsigned long long usage;
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unsigned long long time; /* in US */
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};
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struct cpuidle_state {
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char name[CPUIDLE_NAME_LEN];
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char desc[CPUIDLE_DESC_LEN];
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unsigned int flags;
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unsigned int exit_latency; /* in US */
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int power_usage; /* in mW */
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unsigned int target_residency; /* in US */
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bool disabled; /* disabled on all CPUs */
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int (*enter) (struct cpuidle_device *dev,
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struct cpuidle_driver *drv,
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int index);
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int (*enter_dead) (struct cpuidle_device *dev, int index);
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};
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/* Idle State Flags */
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#define CPUIDLE_FLAG_TIME_VALID (0x01) /* is residency time measurable? */
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#define CPUIDLE_DRIVER_FLAGS_MASK (0xFFFF0000)
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/**
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* cpuidle_get_statedata - retrieves private driver state data
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* @st_usage: the state usage statistics
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*/
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static inline void *cpuidle_get_statedata(struct cpuidle_state_usage *st_usage)
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{
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return st_usage->driver_data;
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}
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/**
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* cpuidle_set_statedata - stores private driver state data
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* @st_usage: the state usage statistics
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* @data: the private data
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*/
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static inline void
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cpuidle_set_statedata(struct cpuidle_state_usage *st_usage, void *data)
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{
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st_usage->driver_data = data;
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}
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struct cpuidle_state_kobj {
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struct cpuidle_state *state;
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struct cpuidle_state_usage *state_usage;
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struct completion kobj_unregister;
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struct kobject kobj;
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};
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struct cpuidle_device {
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unsigned int registered:1;
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unsigned int enabled:1;
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unsigned int cpu;
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int last_residency;
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int state_count;
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struct cpuidle_state_usage states_usage[CPUIDLE_STATE_MAX];
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struct cpuidle_state_kobj *kobjs[CPUIDLE_STATE_MAX];
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struct list_head device_list;
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struct kobject kobj;
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struct completion kobj_unregister;
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};
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DECLARE_PER_CPU(struct cpuidle_device *, cpuidle_devices);
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/**
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* cpuidle_get_last_residency - retrieves the last state's residency time
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* @dev: the target CPU
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*
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* NOTE: this value is invalid if CPUIDLE_FLAG_TIME_VALID isn't set
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*/
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static inline int cpuidle_get_last_residency(struct cpuidle_device *dev)
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{
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return dev->last_residency;
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}
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/****************************
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* CPUIDLE DRIVER INTERFACE *
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****************************/
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struct cpuidle_driver {
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const char *name;
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struct module *owner;
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unsigned int power_specified:1;
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/* set to 1 to use the core cpuidle time keeping (for all states). */
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unsigned int en_core_tk_irqen:1;
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struct cpuidle_state states[CPUIDLE_STATE_MAX];
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int state_count;
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int safe_state_index;
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};
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#ifdef CONFIG_CPU_IDLE
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extern void disable_cpuidle(void);
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extern int cpuidle_idle_call(void);
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extern int cpuidle_register_driver(struct cpuidle_driver *drv);
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extern struct cpuidle_driver *cpuidle_get_driver(void);
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extern struct cpuidle_driver *cpuidle_driver_ref(void);
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extern void cpuidle_driver_unref(void);
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extern void cpuidle_unregister_driver(struct cpuidle_driver *drv);
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extern int cpuidle_register_device(struct cpuidle_device *dev);
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extern void cpuidle_unregister_device(struct cpuidle_device *dev);
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extern void cpuidle_pause_and_lock(void);
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extern void cpuidle_resume_and_unlock(void);
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extern int cpuidle_enable_device(struct cpuidle_device *dev);
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extern void cpuidle_disable_device(struct cpuidle_device *dev);
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extern int cpuidle_wrap_enter(struct cpuidle_device *dev,
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struct cpuidle_driver *drv, int index,
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int (*enter)(struct cpuidle_device *dev,
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struct cpuidle_driver *drv, int index));
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extern int cpuidle_play_dead(void);
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#else
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static inline void disable_cpuidle(void) { }
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static inline int cpuidle_idle_call(void) { return -ENODEV; }
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static inline int cpuidle_register_driver(struct cpuidle_driver *drv)
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{return -ENODEV; }
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static inline struct cpuidle_driver *cpuidle_get_driver(void) {return NULL; }
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static inline struct cpuidle_driver *cpuidle_driver_ref(void) {return NULL; }
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static inline void cpuidle_driver_unref(void) {}
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static inline void cpuidle_unregister_driver(struct cpuidle_driver *drv) { }
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static inline int cpuidle_register_device(struct cpuidle_device *dev)
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{return -ENODEV; }
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static inline void cpuidle_unregister_device(struct cpuidle_device *dev) { }
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static inline void cpuidle_pause_and_lock(void) { }
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static inline void cpuidle_resume_and_unlock(void) { }
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static inline int cpuidle_enable_device(struct cpuidle_device *dev)
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{return -ENODEV; }
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static inline void cpuidle_disable_device(struct cpuidle_device *dev) { }
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static inline int cpuidle_wrap_enter(struct cpuidle_device *dev,
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struct cpuidle_driver *drv, int index,
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int (*enter)(struct cpuidle_device *dev,
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struct cpuidle_driver *drv, int index))
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{ return -ENODEV; }
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static inline int cpuidle_play_dead(void) {return -ENODEV; }
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#endif
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/******************************
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* CPUIDLE GOVERNOR INTERFACE *
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******************************/
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struct cpuidle_governor {
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char name[CPUIDLE_NAME_LEN];
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struct list_head governor_list;
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unsigned int rating;
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int (*enable) (struct cpuidle_driver *drv,
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struct cpuidle_device *dev);
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void (*disable) (struct cpuidle_driver *drv,
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struct cpuidle_device *dev);
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int (*select) (struct cpuidle_driver *drv,
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struct cpuidle_device *dev);
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void (*reflect) (struct cpuidle_device *dev, int index);
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struct module *owner;
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};
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#ifdef CONFIG_CPU_IDLE
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extern int cpuidle_register_governor(struct cpuidle_governor *gov);
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extern void cpuidle_unregister_governor(struct cpuidle_governor *gov);
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#ifdef CONFIG_INTEL_IDLE
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extern int intel_idle_cpu_init(int cpu);
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#else
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static inline int intel_idle_cpu_init(int cpu) { return -1; }
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#endif
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#else
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static inline int intel_idle_cpu_init(int cpu) { return -1; }
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static inline int cpuidle_register_governor(struct cpuidle_governor *gov)
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{return 0;}
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static inline void cpuidle_unregister_governor(struct cpuidle_governor *gov) { }
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#endif
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#ifdef CONFIG_ARCH_HAS_CPU_RELAX
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#define CPUIDLE_DRIVER_STATE_START 1
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#else
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#define CPUIDLE_DRIVER_STATE_START 0
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#endif
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#endif /* _LINUX_CPUIDLE_H */
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