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linux-next/include/linux/cpuidle.h
Daniel Lezcano bf4d1b5ddb cpuidle: support multiple drivers 
With the tegra3 and the big.LITTLE [1] new architectures, several cpus
with different characteristics (latencies and states) can co-exists on the
system.

The cpuidle framework has the limitation of handling only identical cpus.

This patch removes this limitation by introducing the multiple driver support
for cpuidle.

This option is configurable at compile time and should be enabled for the
architectures mentioned above. So there is no impact for the other platforms
if the option is disabled. The option defaults to 'n'. Note the multiple drivers
support is also compatible with the existing drivers, even if just one driver is
needed, all the cpu will be tied to this driver using an extra small chunk of
processor memory.

The multiple driver support use a per-cpu driver pointer instead of a global
variable and the accessor to this variable are done from a cpu context.

In order to keep the compatibility with the existing drivers, the function
'cpuidle_register_driver' and 'cpuidle_unregister_driver' will register
the specified driver for all the cpus.

The semantic for the output of /sys/devices/system/cpu/cpuidle/current_driver
remains the same except the driver name will be related to the current cpu.

The /sys/devices/system/cpu/cpu[0-9]/cpuidle/driver/name files are added
allowing to read the per cpu driver name.

[1] http://lwn.net/Articles/481055/

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Peter De Schrijver <pdeschrijver@nvidia.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2012-11-15 00:34:23 +01:00

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/*
* cpuidle.h - a generic framework for CPU idle power management
*
* (C) 2007 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
* Shaohua Li <shaohua.li@intel.com>
* Adam Belay <abelay@novell.com>
*
* This code is licenced under the GPL.
*/
#ifndef _LINUX_CPUIDLE_H
#define _LINUX_CPUIDLE_H
#include <linux/percpu.h>
#include <linux/list.h>
#include <linux/kobject.h>
#include <linux/completion.h>
#include <linux/hrtimer.h>
#define CPUIDLE_STATE_MAX 8
#define CPUIDLE_NAME_LEN 16
#define CPUIDLE_DESC_LEN 32
struct module;
struct cpuidle_device;
struct cpuidle_driver;
/****************************
* CPUIDLE DEVICE INTERFACE *
****************************/
struct cpuidle_state_usage {
void *driver_data;
unsigned long long disable;
unsigned long long usage;
unsigned long long time; /* in US */
};
struct cpuidle_state {
char name[CPUIDLE_NAME_LEN];
char desc[CPUIDLE_DESC_LEN];
unsigned int flags;
unsigned int exit_latency; /* in US */
int power_usage; /* in mW */
unsigned int target_residency; /* in US */
bool disabled; /* disabled on all CPUs */
int (*enter) (struct cpuidle_device *dev,
struct cpuidle_driver *drv,
int index);
int (*enter_dead) (struct cpuidle_device *dev, int index);
};
/* Idle State Flags */
#define CPUIDLE_FLAG_TIME_VALID (0x01) /* is residency time measurable? */
#define CPUIDLE_FLAG_COUPLED (0x02) /* state applies to multiple cpus */
#define CPUIDLE_DRIVER_FLAGS_MASK (0xFFFF0000)
/**
* cpuidle_get_statedata - retrieves private driver state data
* @st_usage: the state usage statistics
*/
static inline void *cpuidle_get_statedata(struct cpuidle_state_usage *st_usage)
{
return st_usage->driver_data;
}
/**
* cpuidle_set_statedata - stores private driver state data
* @st_usage: the state usage statistics
* @data: the private data
*/
static inline void
cpuidle_set_statedata(struct cpuidle_state_usage *st_usage, void *data)
{
st_usage->driver_data = data;
}
struct cpuidle_device {
unsigned int registered:1;
unsigned int enabled:1;
unsigned int cpu;
int last_residency;
int state_count;
struct cpuidle_state_usage states_usage[CPUIDLE_STATE_MAX];
struct cpuidle_state_kobj *kobjs[CPUIDLE_STATE_MAX];
struct cpuidle_driver_kobj *kobj_driver;
struct list_head device_list;
struct kobject kobj;
struct completion kobj_unregister;
#ifdef CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED
int safe_state_index;
cpumask_t coupled_cpus;
struct cpuidle_coupled *coupled;
#endif
};
DECLARE_PER_CPU(struct cpuidle_device *, cpuidle_devices);
/**
* cpuidle_get_last_residency - retrieves the last state's residency time
* @dev: the target CPU
*
* NOTE: this value is invalid if CPUIDLE_FLAG_TIME_VALID isn't set
*/
static inline int cpuidle_get_last_residency(struct cpuidle_device *dev)
{
return dev->last_residency;
}
/****************************
* CPUIDLE DRIVER INTERFACE *
****************************/
struct cpuidle_driver {
const char *name;
struct module *owner;
int refcnt;
unsigned int power_specified:1;
/* set to 1 to use the core cpuidle time keeping (for all states). */
unsigned int en_core_tk_irqen:1;
struct cpuidle_state states[CPUIDLE_STATE_MAX];
int state_count;
int safe_state_index;
};
#ifdef CONFIG_CPU_IDLE
extern void disable_cpuidle(void);
extern int cpuidle_idle_call(void);
extern int cpuidle_register_driver(struct cpuidle_driver *drv);
extern struct cpuidle_driver *cpuidle_get_driver(void);
extern struct cpuidle_driver *cpuidle_driver_ref(void);
extern void cpuidle_driver_unref(void);
extern void cpuidle_unregister_driver(struct cpuidle_driver *drv);
extern int cpuidle_register_device(struct cpuidle_device *dev);
extern void cpuidle_unregister_device(struct cpuidle_device *dev);
extern void cpuidle_pause_and_lock(void);
extern void cpuidle_resume_and_unlock(void);
extern void cpuidle_pause(void);
extern void cpuidle_resume(void);
extern int cpuidle_enable_device(struct cpuidle_device *dev);
extern void cpuidle_disable_device(struct cpuidle_device *dev);
extern int cpuidle_wrap_enter(struct cpuidle_device *dev,
struct cpuidle_driver *drv, int index,
int (*enter)(struct cpuidle_device *dev,
struct cpuidle_driver *drv, int index));
extern int cpuidle_play_dead(void);
extern struct cpuidle_driver *cpuidle_get_cpu_driver(struct cpuidle_device *dev);
extern int cpuidle_register_cpu_driver(struct cpuidle_driver *drv, int cpu);
extern void cpuidle_unregister_cpu_driver(struct cpuidle_driver *drv, int cpu);
#else
static inline void disable_cpuidle(void) { }
static inline int cpuidle_idle_call(void) { return -ENODEV; }
static inline int cpuidle_register_driver(struct cpuidle_driver *drv)
{return -ENODEV; }
static inline struct cpuidle_driver *cpuidle_get_driver(void) {return NULL; }
static inline struct cpuidle_driver *cpuidle_driver_ref(void) {return NULL; }
static inline void cpuidle_driver_unref(void) {}
static inline void cpuidle_unregister_driver(struct cpuidle_driver *drv) { }
static inline int cpuidle_register_device(struct cpuidle_device *dev)
{return -ENODEV; }
static inline void cpuidle_unregister_device(struct cpuidle_device *dev) { }
static inline void cpuidle_pause_and_lock(void) { }
static inline void cpuidle_resume_and_unlock(void) { }
static inline void cpuidle_pause(void) { }
static inline void cpuidle_resume(void) { }
static inline int cpuidle_enable_device(struct cpuidle_device *dev)
{return -ENODEV; }
static inline void cpuidle_disable_device(struct cpuidle_device *dev) { }
static inline int cpuidle_wrap_enter(struct cpuidle_device *dev,
struct cpuidle_driver *drv, int index,
int (*enter)(struct cpuidle_device *dev,
struct cpuidle_driver *drv, int index))
{ return -ENODEV; }
static inline int cpuidle_play_dead(void) {return -ENODEV; }
#endif
#ifdef CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED
void cpuidle_coupled_parallel_barrier(struct cpuidle_device *dev, atomic_t *a);
#else
static inline void cpuidle_coupled_parallel_barrier(struct cpuidle_device *dev, atomic_t *a)
{
}
#endif
/******************************
* CPUIDLE GOVERNOR INTERFACE *
******************************/
struct cpuidle_governor {
char name[CPUIDLE_NAME_LEN];
struct list_head governor_list;
unsigned int rating;
int (*enable) (struct cpuidle_driver *drv,
struct cpuidle_device *dev);
void (*disable) (struct cpuidle_driver *drv,
struct cpuidle_device *dev);
int (*select) (struct cpuidle_driver *drv,
struct cpuidle_device *dev);
void (*reflect) (struct cpuidle_device *dev, int index);
struct module *owner;
};
#ifdef CONFIG_CPU_IDLE
extern int cpuidle_register_governor(struct cpuidle_governor *gov);
extern void cpuidle_unregister_governor(struct cpuidle_governor *gov);
#else
static inline int cpuidle_register_governor(struct cpuidle_governor *gov)
{return 0;}
static inline void cpuidle_unregister_governor(struct cpuidle_governor *gov) { }
#endif
#ifdef CONFIG_ARCH_HAS_CPU_RELAX
#define CPUIDLE_DRIVER_STATE_START 1
#else
#define CPUIDLE_DRIVER_STATE_START 0
#endif
#endif /* _LINUX_CPUIDLE_H */
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