/*
 * 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/hrtimer.h>
#include <linux/context_tracking.h>

#define CPUIDLE_STATE_MAX       10
#define CPUIDLE_NAME_LEN        16
#define CPUIDLE_DESC_LEN        32

struct module;

struct cpuidle_device;
struct cpuidle_driver;


/****************************
 * CPUIDLE DEVICE INTERFACE *
 ****************************/

#define CPUIDLE_STATE_DISABLED_BY_USER          BIT(0)
#define CPUIDLE_STATE_DISABLED_BY_DRIVER        BIT(1)

struct cpuidle_state_usage {
        unsigned long long      disable;
        unsigned long long      usage;
        u64                     time_ns;
        unsigned long long      above; /* Number of times it's been too deep */
        unsigned long long      below; /* Number of times it's been too shallow */
        unsigned long long      rejected; /* Number of times idle entry was rejected */
#ifdef CONFIG_SUSPEND
        unsigned long long      s2idle_usage;
        unsigned long long      s2idle_time; /* in US */
#endif
};

struct cpuidle_state {
        char            name[CPUIDLE_NAME_LEN];
        char            desc[CPUIDLE_DESC_LEN];

        s64             exit_latency_ns;
        s64             target_residency_ns;
        unsigned int    flags;
        unsigned int    exit_latency; /* in US */
        int             power_usage; /* in mW */
        unsigned int    target_residency; /* in US */

        int (*enter)    (struct cpuidle_device *dev,
                        struct cpuidle_driver *drv,
                        int index);

        void (*enter_dead) (struct cpuidle_device *dev, int index);

        /*
         * CPUs execute ->enter_s2idle with the local tick or entire timekeeping
         * suspended, so it must not re-enable interrupts at any point (even
         * temporarily) or attempt to change states of clock event devices.
         *
         * This callback may point to the same function as ->enter if all of
         * the above requirements are met by it.
         */
        int (*enter_s2idle)(struct cpuidle_device *dev,
                            struct cpuidle_driver *drv,
                            int index);
};

/* Idle State Flags */
#define CPUIDLE_FLAG_NONE               (0x00)
#define CPUIDLE_FLAG_POLLING            BIT(0) /* polling state */
#define CPUIDLE_FLAG_COUPLED            BIT(1) /* state applies to multiple cpus */
#define CPUIDLE_FLAG_TIMER_STOP         BIT(2) /* timer is stopped on this state */
#define CPUIDLE_FLAG_UNUSABLE           BIT(3) /* avoid using this state */
#define CPUIDLE_FLAG_OFF                BIT(4) /* disable this state by default */
#define CPUIDLE_FLAG_TLB_FLUSHED        BIT(5) /* idle-state flushes TLBs */
#define CPUIDLE_FLAG_RCU_IDLE           BIT(6) /* idle-state takes care of RCU */

struct cpuidle_device_kobj;
struct cpuidle_state_kobj;
struct cpuidle_driver_kobj;

struct cpuidle_device {
        unsigned int            registered:1;
        unsigned int            enabled:1;
        unsigned int            poll_time_limit:1;
        unsigned int            cpu;
        ktime_t                 next_hrtimer;

        int                     last_state_idx;
        u64                     last_residency_ns;
        u64                     poll_limit_ns;
        u64                     forced_idle_latency_limit_ns;
        struct cpuidle_state_usage      states_usage[CPUIDLE_STATE_MAX];
        struct cpuidle_state_kobj *kobjs[CPUIDLE_STATE_MAX];
        struct cpuidle_driver_kobj *kobj_driver;
        struct cpuidle_device_kobj *kobj_dev;
        struct list_head        device_list;

#ifdef CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED
        cpumask_t               coupled_cpus;
        struct cpuidle_coupled  *coupled;
#endif
};

DECLARE_PER_CPU(struct cpuidle_device *, cpuidle_devices);
DECLARE_PER_CPU(struct cpuidle_device, cpuidle_dev);

static __always_inline void ct_cpuidle_enter(void)
{
        lockdep_assert_irqs_disabled();
        /*
         * Idle is allowed to (temporary) enable IRQs. It
         * will return with IRQs disabled.
         *
         * Trace IRQs enable here, then switch off RCU, and have
         * arch_cpu_idle() use raw_local_irq_enable(). Note that
         * ct_idle_enter() relies on lockdep IRQ state, so switch that
         * last -- this is very similar to the entry code.
         */
        trace_hardirqs_on_prepare();
        lockdep_hardirqs_on_prepare();
        instrumentation_end();
        ct_idle_enter();
        lockdep_hardirqs_on(_RET_IP_);
}

static __always_inline void ct_cpuidle_exit(void)
{
        /*
         * Carefully undo the above.
         */
        lockdep_hardirqs_off(_RET_IP_);
        ct_idle_exit();
        instrumentation_begin();
}

/****************************
 * CPUIDLE DRIVER INTERFACE *
 ****************************/

struct cpuidle_driver {
        const char              *name;
        struct module           *owner;

        /* used by the cpuidle framework to setup the broadcast timer */
        unsigned int            bctimer:1;
        /* states array must be ordered in decreasing power consumption */
        struct cpuidle_state    states[CPUIDLE_STATE_MAX];
        int                     state_count;
        int                     safe_state_index;

        /* the driver handles the cpus in cpumask */
        struct cpumask          *cpumask;

        /* preferred governor to switch at register time */
        const char              *governor;
};

#ifdef CONFIG_CPU_IDLE
extern void disable_cpuidle(void);
extern bool cpuidle_not_available(struct cpuidle_driver *drv,
                                  struct cpuidle_device *dev);

extern int cpuidle_select(struct cpuidle_driver *drv,
                          struct cpuidle_device *dev,
                          bool *stop_tick);
extern int cpuidle_enter(struct cpuidle_driver *drv,
                         struct cpuidle_device *dev, int index);
extern void cpuidle_reflect(struct cpuidle_device *dev, int index);
extern u64 cpuidle_poll_time(struct cpuidle_driver *drv,
                             struct cpuidle_device *dev);

extern int cpuidle_register_driver(struct cpuidle_driver *drv);
extern struct cpuidle_driver *cpuidle_get_driver(void);
extern void cpuidle_driver_state_disabled(struct cpuidle_driver *drv, int idx,
                                        bool disable);
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 int cpuidle_register(struct cpuidle_driver *drv,
                            const struct cpumask *const coupled_cpus);
extern void cpuidle_unregister(struct cpuidle_driver *drv);
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_play_dead(void);

extern struct cpuidle_driver *cpuidle_get_cpu_driver(struct cpuidle_device *dev);
static inline struct cpuidle_device *cpuidle_get_device(void)
{return __this_cpu_read(cpuidle_devices); }
#else
static inline void disable_cpuidle(void) { }
static inline bool cpuidle_not_available(struct cpuidle_driver *drv,
                                         struct cpuidle_device *dev)
{return true; }
static inline int cpuidle_select(struct cpuidle_driver *drv,
                                 struct cpuidle_device *dev, bool *stop_tick)
{return -ENODEV; }
static inline int cpuidle_enter(struct cpuidle_driver *drv,
                                struct cpuidle_device *dev, int index)
{return -ENODEV; }
static inline void cpuidle_reflect(struct cpuidle_device *dev, int index) { }
static inline u64 cpuidle_poll_time(struct cpuidle_driver *drv,
                             struct cpuidle_device *dev)
{return 0; }
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 void cpuidle_driver_state_disabled(struct cpuidle_driver *drv,
                                               int idx, bool disable) { }
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 int cpuidle_register(struct cpuidle_driver *drv,
                                   const struct cpumask *const coupled_cpus)
{return -ENODEV; }
static inline void cpuidle_unregister(struct cpuidle_driver *drv) { }
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_play_dead(void) {return -ENODEV; }
static inline struct cpuidle_driver *cpuidle_get_cpu_driver(
        struct cpuidle_device *dev) {return NULL; }
static inline struct cpuidle_device *cpuidle_get_device(void) {return NULL; }
#endif

#ifdef CONFIG_CPU_IDLE
extern int cpuidle_find_deepest_state(struct cpuidle_driver *drv,
                                      struct cpuidle_device *dev,
                                      u64 latency_limit_ns);
extern int cpuidle_enter_s2idle(struct cpuidle_driver *drv,
                                struct cpuidle_device *dev,
                                u64 latency_limit_ns);
extern void cpuidle_use_deepest_state(u64 latency_limit_ns);
#else
static inline int cpuidle_find_deepest_state(struct cpuidle_driver *drv,
                                             struct cpuidle_device *dev,
                                             u64 latency_limit_ns)
{return -ENODEV; }
static inline int cpuidle_enter_s2idle(struct cpuidle_driver *drv,
                                       struct cpuidle_device *dev,
                                       u64 latency_limit_ns)
{return -ENODEV; }
static inline void cpuidle_use_deepest_state(u64 latency_limit_ns)
{
}
#endif

/* kernel/sched/idle.c */
extern void sched_idle_set_state(struct cpuidle_state *idle_state);
extern void default_idle_call(void);

#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

#if defined(CONFIG_CPU_IDLE) && defined(CONFIG_ARCH_HAS_CPU_RELAX)
void cpuidle_poll_state_init(struct cpuidle_driver *drv);
#else
static inline void cpuidle_poll_state_init(struct cpuidle_driver *drv) {}
#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,
                                        bool *stop_tick);
        void (*reflect)         (struct cpuidle_device *dev, int index);
};

extern int cpuidle_register_governor(struct cpuidle_governor *gov);
extern s64 cpuidle_governor_latency_req(unsigned int cpu);

#define __CPU_PM_CPU_IDLE_ENTER(low_level_idle_enter,                   \
                                idx,                                    \
                                state,                                  \
                                is_retention, is_rcu)                   \
({                                                                      \
        int __ret = 0;                                                  \
                                                                        \
        if (!idx) {                                                     \
                cpu_do_idle();                                          \
                return idx;                                             \
        }                                                               \
                                                                        \
        if (!is_retention)                                              \
                __ret =  cpu_pm_enter();                                \
        if (!__ret) {                                                   \
                if (!is_rcu)                                            \
                        ct_cpuidle_enter();                             \
                __ret = low_level_idle_enter(state);                    \
                if (!is_rcu)                                            \
                        ct_cpuidle_exit();                              \
                if (!is_retention)                                      \
                        cpu_pm_exit();                                  \
        }                                                               \
                                                                        \
        __ret ? -1 : idx;                                               \
})

#define CPU_PM_CPU_IDLE_ENTER(low_level_idle_enter, idx)        \
        __CPU_PM_CPU_IDLE_ENTER(low_level_idle_enter, idx, idx, 0, 0)

#define CPU_PM_CPU_IDLE_ENTER_RETENTION(low_level_idle_enter, idx)      \
        __CPU_PM_CPU_IDLE_ENTER(low_level_idle_enter, idx, idx, 1, 0)

#define CPU_PM_CPU_IDLE_ENTER_PARAM(low_level_idle_enter, idx, state)   \
        __CPU_PM_CPU_IDLE_ENTER(low_level_idle_enter, idx, state, 0, 0)

#define CPU_PM_CPU_IDLE_ENTER_PARAM_RCU(low_level_idle_enter, idx, state)       \
        __CPU_PM_CPU_IDLE_ENTER(low_level_idle_enter, idx, state, 0, 1)

#define CPU_PM_CPU_IDLE_ENTER_RETENTION_PARAM(low_level_idle_enter, idx, state) \
        __CPU_PM_CPU_IDLE_ENTER(low_level_idle_enter, idx, state, 1, 0)

#define CPU_PM_CPU_IDLE_ENTER_RETENTION_PARAM_RCU(low_level_idle_enter, idx, state)     \
        __CPU_PM_CPU_IDLE_ENTER(low_level_idle_enter, idx, state, 1, 1)

#endif /* _LINUX_CPUIDLE_H */