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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/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