[deliverable/linux.git] / drivers / cpuidle / cpuidle.c

/*
 * cpuidle.c - core cpuidle infrastructure
 *
 * (C) 2006-2007 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
 *               Shaohua Li <shaohua.li@intel.com>
 *               Adam Belay <abelay@novell.com>
 *
 * This code is licenced under the GPL.
 */

#include <linux/kernel.h>
#include <linux/mutex.h>
#include <linux/sched.h>
#include <linux/notifier.h>
#include <linux/pm_qos.h>
#include <linux/cpu.h>
#include <linux/cpuidle.h>
#include <linux/ktime.h>
#include <linux/hrtimer.h>
#include <linux/module.h>
#include <trace/events/power.h>

#include "cpuidle.h"

DEFINE_PER_CPU(struct cpuidle_device *, cpuidle_devices);

DEFINE_MUTEX(cpuidle_lock);
LIST_HEAD(cpuidle_detected_devices);

static int enabled_devices;
static int off __read_mostly;
static int initialized __read_mostly;

int cpuidle_disabled(void)
{
	return off;
}
void disable_cpuidle(void)
{
	off = 1;
}

static int __cpuidle_register_device(struct cpuidle_device *dev);

static inline int cpuidle_enter(struct cpuidle_device *dev,
				struct cpuidle_driver *drv, int index)
{
	struct cpuidle_state *target_state = &drv->states[index];
	return target_state->enter(dev, drv, index);
}

static inline int cpuidle_enter_tk(struct cpuidle_device *dev,
			       struct cpuidle_driver *drv, int index)
{
	return cpuidle_wrap_enter(dev, drv, index, cpuidle_enter);
}

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

static cpuidle_enter_t cpuidle_enter_ops;

/**
 * cpuidle_play_dead - cpu off-lining
 *
 * Returns in case of an error or no driver
 */
int cpuidle_play_dead(void)
{
	struct cpuidle_device *dev = __this_cpu_read(cpuidle_devices);
	struct cpuidle_driver *drv = cpuidle_get_driver();
	int i, dead_state = -1;
	int power_usage = -1;

	if (!drv)
		return -ENODEV;

	/* Find lowest-power state that supports long-term idle */
	for (i = CPUIDLE_DRIVER_STATE_START; i < drv->state_count; i++) {
		struct cpuidle_state *s = &drv->states[i];

		if (s->power_usage < power_usage && s->enter_dead) {
			power_usage = s->power_usage;
			dead_state = i;
		}
	}

	if (dead_state != -1)
		return drv->states[dead_state].enter_dead(dev, dead_state);

	return -ENODEV;
}

/**
 * cpuidle_enter_state - enter the state and update stats
 * @dev: cpuidle device for this cpu
 * @drv: cpuidle driver for this cpu
 * @next_state: index into drv->states of the state to enter
 */
int cpuidle_enter_state(struct cpuidle_device *dev, struct cpuidle_driver *drv,
		int next_state)
{
	int entered_state;

	entered_state = cpuidle_enter_ops(dev, drv, next_state);

	if (entered_state >= 0) {
		/* Update cpuidle counters */
		/* This can be moved to within driver enter routine
		 * but that results in multiple copies of same code.
		 */
		dev->states_usage[entered_state].time +=
				(unsigned long long)dev->last_residency;
		dev->states_usage[entered_state].usage++;
	} else {
		dev->last_residency = 0;
	}

	return entered_state;
}

/**
 * cpuidle_idle_call - the main idle loop
 *
 * NOTE: no locks or semaphores should be used here
 * return non-zero on failure
 */
int cpuidle_idle_call(void)
{
	struct cpuidle_device *dev = __this_cpu_read(cpuidle_devices);
	struct cpuidle_driver *drv = cpuidle_get_driver();
	int next_state, entered_state;

	if (off)
		return -ENODEV;

	if (!initialized)
		return -ENODEV;

	/* check if the device is ready */
	if (!dev || !dev->enabled)
		return -EBUSY;

	/* ask the governor for the next state */
	next_state = cpuidle_curr_governor->select(drv, dev);
	if (need_resched()) {
		local_irq_enable();
		return 0;
	}

	trace_power_start_rcuidle(POWER_CSTATE, next_state, dev->cpu);
	trace_cpu_idle_rcuidle(next_state, dev->cpu);

	if (cpuidle_state_is_coupled(dev, drv, next_state))
		entered_state = cpuidle_enter_state_coupled(dev, drv,
							    next_state);
	else
		entered_state = cpuidle_enter_state(dev, drv, next_state);

	trace_power_end_rcuidle(dev->cpu);
	trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, dev->cpu);

	/* give the governor an opportunity to reflect on the outcome */
	if (cpuidle_curr_governor->reflect)
		cpuidle_curr_governor->reflect(dev, entered_state);

	return 0;
}

/**
 * cpuidle_install_idle_handler - installs the cpuidle idle loop handler
 */
void cpuidle_install_idle_handler(void)
{
	if (enabled_devices) {
		/* Make sure all changes finished before we switch to new idle */
		smp_wmb();
		initialized = 1;
	}
}

/**
 * cpuidle_uninstall_idle_handler - uninstalls the cpuidle idle loop handler
 */
void cpuidle_uninstall_idle_handler(void)
{
	if (enabled_devices) {
		initialized = 0;
		kick_all_cpus_sync();
	}
}

/**
 * cpuidle_pause_and_lock - temporarily disables CPUIDLE
 */
void cpuidle_pause_and_lock(void)
{
	mutex_lock(&cpuidle_lock);
	cpuidle_uninstall_idle_handler();
}

EXPORT_SYMBOL_GPL(cpuidle_pause_and_lock);

/**
 * cpuidle_resume_and_unlock - resumes CPUIDLE operation
 */
void cpuidle_resume_and_unlock(void)
{
	cpuidle_install_idle_handler();
	mutex_unlock(&cpuidle_lock);
}

EXPORT_SYMBOL_GPL(cpuidle_resume_and_unlock);

/* Currently used in suspend/resume path to suspend cpuidle */
void cpuidle_pause(void)
{
	mutex_lock(&cpuidle_lock);
	cpuidle_uninstall_idle_handler();
	mutex_unlock(&cpuidle_lock);
}

/* Currently used in suspend/resume path to resume cpuidle */
void cpuidle_resume(void)
{
	mutex_lock(&cpuidle_lock);
	cpuidle_install_idle_handler();
	mutex_unlock(&cpuidle_lock);
}

/**
 * cpuidle_wrap_enter - performs timekeeping and irqen around enter function
 * @dev: pointer to a valid cpuidle_device object
 * @drv: pointer to a valid cpuidle_driver object
 * @index: index of the target cpuidle state.
 */
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))
{
	ktime_t time_start, time_end;
	s64 diff;

	time_start = ktime_get();

	index = enter(dev, drv, index);

	time_end = ktime_get();

	local_irq_enable();

	diff = ktime_to_us(ktime_sub(time_end, time_start));
	if (diff > INT_MAX)
		diff = INT_MAX;

	dev->last_residency = (int) diff;

	return index;
}

#ifdef CONFIG_ARCH_HAS_CPU_RELAX
static int poll_idle(struct cpuidle_device *dev,
		struct cpuidle_driver *drv, int index)
{
	ktime_t	t1, t2;
	s64 diff;

	t1 = ktime_get();
	local_irq_enable();
	while (!need_resched())
		cpu_relax();

	t2 = ktime_get();
	diff = ktime_to_us(ktime_sub(t2, t1));
	if (diff > INT_MAX)
		diff = INT_MAX;

	dev->last_residency = (int) diff;

	return index;
}

static void poll_idle_init(struct cpuidle_driver *drv)
{
	struct cpuidle_state *state = &drv->states[0];

	snprintf(state->name, CPUIDLE_NAME_LEN, "POLL");
	snprintf(state->desc, CPUIDLE_DESC_LEN, "CPUIDLE CORE POLL IDLE");
	state->exit_latency = 0;
	state->target_residency = 0;
	state->power_usage = -1;
	state->flags = 0;
	state->enter = poll_idle;
	state->disabled = false;
}
#else
static void poll_idle_init(struct cpuidle_driver *drv) {}
#endif /* CONFIG_ARCH_HAS_CPU_RELAX */

/**
 * cpuidle_enable_device - enables idle PM for a CPU
 * @dev: the CPU
 *
 * This function must be called between cpuidle_pause_and_lock and
 * cpuidle_resume_and_unlock when used externally.
 */
int cpuidle_enable_device(struct cpuidle_device *dev)
{
	int ret, i;
	struct cpuidle_driver *drv = cpuidle_get_driver();

	if (!dev)
		return -EINVAL;

	if (dev->enabled)
		return 0;
	if (!drv || !cpuidle_curr_governor)
		return -EIO;
	if (!dev->state_count)
		dev->state_count = drv->state_count;

	if (dev->registered == 0) {
		ret = __cpuidle_register_device(dev);
		if (ret)
			return ret;
	}

	cpuidle_enter_ops = drv->en_core_tk_irqen ?
		cpuidle_enter_tk : cpuidle_enter;

	poll_idle_init(drv);

	if ((ret = cpuidle_add_state_sysfs(dev)))
		return ret;

	if (cpuidle_curr_governor->enable &&
	    (ret = cpuidle_curr_governor->enable(drv, dev)))
		goto fail_sysfs;

	for (i = 0; i < dev->state_count; i++) {
		dev->states_usage[i].usage = 0;
		dev->states_usage[i].time = 0;
	}
	dev->last_residency = 0;

	smp_wmb();

	dev->enabled = 1;

	enabled_devices++;
	return 0;

fail_sysfs:
	cpuidle_remove_state_sysfs(dev);

	return ret;
}

EXPORT_SYMBOL_GPL(cpuidle_enable_device);

/**
 * cpuidle_disable_device - disables idle PM for a CPU
 * @dev: the CPU
 *
 * This function must be called between cpuidle_pause_and_lock and
 * cpuidle_resume_and_unlock when used externally.
 */
void cpuidle_disable_device(struct cpuidle_device *dev)
{
	if (!dev || !dev->enabled)
		return;
	if (!cpuidle_get_driver() || !cpuidle_curr_governor)
		return;

	dev->enabled = 0;

	if (cpuidle_curr_governor->disable)
		cpuidle_curr_governor->disable(cpuidle_get_driver(), dev);

	cpuidle_remove_state_sysfs(dev);
	enabled_devices--;
}

EXPORT_SYMBOL_GPL(cpuidle_disable_device);

/**
 * __cpuidle_register_device - internal register function called before register
 * and enable routines
 * @dev: the cpu
 *
 * cpuidle_lock mutex must be held before this is called
 */
static int __cpuidle_register_device(struct cpuidle_device *dev)
{
	int ret;
	struct device *cpu_dev = get_cpu_device((unsigned long)dev->cpu);
	struct cpuidle_driver *cpuidle_driver = cpuidle_get_driver();

	if (!try_module_get(cpuidle_driver->owner))
		return -EINVAL;

	init_completion(&dev->kobj_unregister);

	per_cpu(cpuidle_devices, dev->cpu) = dev;
	list_add(&dev->device_list, &cpuidle_detected_devices);
	ret = cpuidle_add_sysfs(cpu_dev);
	if (ret)
		goto err_sysfs;

	ret = cpuidle_coupled_register_device(dev);
	if (ret)
		goto err_coupled;

	dev->registered = 1;
	return 0;

err_coupled:
	cpuidle_remove_sysfs(cpu_dev);
	wait_for_completion(&dev->kobj_unregister);
err_sysfs:
	list_del(&dev->device_list);
	per_cpu(cpuidle_devices, dev->cpu) = NULL;
	module_put(cpuidle_driver->owner);
	return ret;
}

/**
 * cpuidle_register_device - registers a CPU's idle PM feature
 * @dev: the cpu
 */
int cpuidle_register_device(struct cpuidle_device *dev)
{
	int ret;

	if (!dev)
		return -EINVAL;

	mutex_lock(&cpuidle_lock);

	if ((ret = __cpuidle_register_device(dev))) {
		mutex_unlock(&cpuidle_lock);
		return ret;
	}

	cpuidle_enable_device(dev);
	cpuidle_install_idle_handler();

	mutex_unlock(&cpuidle_lock);

	return 0;

}

EXPORT_SYMBOL_GPL(cpuidle_register_device);

/**
 * cpuidle_unregister_device - unregisters a CPU's idle PM feature
 * @dev: the cpu
 */
void cpuidle_unregister_device(struct cpuidle_device *dev)
{
	struct device *cpu_dev = get_cpu_device((unsigned long)dev->cpu);
	struct cpuidle_driver *cpuidle_driver = cpuidle_get_driver();

	if (dev->registered == 0)
		return;

	cpuidle_pause_and_lock();

	cpuidle_disable_device(dev);

	cpuidle_remove_sysfs(cpu_dev);
	list_del(&dev->device_list);
	wait_for_completion(&dev->kobj_unregister);
	per_cpu(cpuidle_devices, dev->cpu) = NULL;

	cpuidle_coupled_unregister_device(dev);

	cpuidle_resume_and_unlock();

	module_put(cpuidle_driver->owner);
}

EXPORT_SYMBOL_GPL(cpuidle_unregister_device);

#ifdef CONFIG_SMP

static void smp_callback(void *v)
{
	/* we already woke the CPU up, nothing more to do */
}

/*
 * This function gets called when a part of the kernel has a new latency
 * requirement.  This means we need to get all processors out of their C-state,
 * and then recalculate a new suitable C-state. Just do a cross-cpu IPI; that
 * wakes them all right up.
 */
static int cpuidle_latency_notify(struct notifier_block *b,
		unsigned long l, void *v)
{
	smp_call_function(smp_callback, NULL, 1);
	return NOTIFY_OK;
}

static struct notifier_block cpuidle_latency_notifier = {
	.notifier_call = cpuidle_latency_notify,
};

static inline void latency_notifier_init(struct notifier_block *n)
{
	pm_qos_add_notifier(PM_QOS_CPU_DMA_LATENCY, n);
}

#else /* CONFIG_SMP */

#define latency_notifier_init(x) do { } while (0)

#endif /* CONFIG_SMP */

/**
 * cpuidle_init - core initializer
 */
static int __init cpuidle_init(void)
{
	int ret;

	if (cpuidle_disabled())
		return -ENODEV;

	ret = cpuidle_add_interface(cpu_subsys.dev_root);
	if (ret)
		return ret;

	latency_notifier_init(&cpuidle_latency_notifier);

	return 0;
}

module_param(off, int, 0444);
core_initcall(cpuidle_init);
Commit	Line	Data
4f86d3a8 LB	1	/*
	2	* cpuidle.c - core cpuidle infrastructure
	3	*
	4	* (C) 2006-2007 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
	5	* Shaohua Li <shaohua.li@intel.com>
	6	* Adam Belay <abelay@novell.com>
	7	*
	8	* This code is licenced under the GPL.
	9	*/
	10
	11	#include <linux/kernel.h>
	12	#include <linux/mutex.h>
	13	#include <linux/sched.h>
	14	#include <linux/notifier.h>
e8db0be1	15	#include <linux/pm_qos.h>
4f86d3a8 LB	16	#include <linux/cpu.h>
4f86d3a8 LB	17	#include <linux/cpuidle.h>
9a0b8415	18	#include <linux/ktime.h>
2e94d1f7	19	#include <linux/hrtimer.h>
884b17e1	20	#include <linux/module.h>
288f023e	21	#include <trace/events/power.h>
4f86d3a8 LB	22
	23	#include "cpuidle.h"
	24
	25	DEFINE_PER_CPU(struct cpuidle_device *, cpuidle_devices);
4f86d3a8 LB	26
	27	DEFINE_MUTEX(cpuidle_lock);
	28	LIST_HEAD(cpuidle_detected_devices);
4f86d3a8 LB	29
4f86d3a8 LB	30	static int enabled_devices;
62027aea	31	static int off __read_mostly;
a0bfa137	32	static int initialized __read_mostly;
62027aea LB	33
	34	int cpuidle_disabled(void)
	35	{
	36	return off;
	37	}
d91ee586 LB	38	void disable_cpuidle(void)
	39	{
	40	off = 1;
	41	}
4f86d3a8	42
dcb84f33 VP	43	static int __cpuidle_register_device(struct cpuidle_device *dev);
dcb84f33 VP	44
e1689795 RL	45	static inline int cpuidle_enter(struct cpuidle_device *dev,
	46	struct cpuidle_driver *drv, int index)
	47	{
	48	struct cpuidle_state *target_state = &drv->states[index];
	49	return target_state->enter(dev, drv, index);
	50	}
	51
	52	static inline int cpuidle_enter_tk(struct cpuidle_device *dev,
	53	struct cpuidle_driver *drv, int index)
	54	{
	55	return cpuidle_wrap_enter(dev, drv, index, cpuidle_enter);
	56	}
	57
	58	typedef int (cpuidle_enter_t)(struct cpuidle_device dev,
	59	struct cpuidle_driver *drv, int index);
	60
	61	static cpuidle_enter_t cpuidle_enter_ops;
	62
1a022e3f BO	63	/**
	64	* cpuidle_play_dead - cpu off-lining
	65	*
ee01e663	66	* Returns in case of an error or no driver
1a022e3f BO	67	*/
	68	int cpuidle_play_dead(void)
	69	{
	70	struct cpuidle_device *dev = __this_cpu_read(cpuidle_devices);
	71	struct cpuidle_driver *drv = cpuidle_get_driver();
	72	int i, dead_state = -1;
	73	int power_usage = -1;
	74
ee01e663 TK	75	if (!drv)
	76	return -ENODEV;
	77
1a022e3f BO	78	/* Find lowest-power state that supports long-term idle */
	79	for (i = CPUIDLE_DRIVER_STATE_START; i < drv->state_count; i++) {
	80	struct cpuidle_state *s = &drv->states[i];
	81
	82	if (s->power_usage < power_usage && s->enter_dead) {
	83	power_usage = s->power_usage;
	84	dead_state = i;
	85	}
	86	}
	87
	88	if (dead_state != -1)
	89	return drv->states[dead_state].enter_dead(dev, dead_state);
	90
	91	return -ENODEV;
	92	}
	93
56cfbf74 CC	94	/**
	95	* cpuidle_enter_state - enter the state and update stats
	96	* @dev: cpuidle device for this cpu
	97	* @drv: cpuidle driver for this cpu
	98	* @next_state: index into drv->states of the state to enter
	99	*/
	100	int cpuidle_enter_state(struct cpuidle_device dev, struct cpuidle_driver drv,
	101	int next_state)
	102	{
	103	int entered_state;
	104
	105	entered_state = cpuidle_enter_ops(dev, drv, next_state);
	106
	107	if (entered_state >= 0) {
	108	/* Update cpuidle counters */
	109	/* This can be moved to within driver enter routine
	110	* but that results in multiple copies of same code.
	111	*/
	112	dev->states_usage[entered_state].time +=
	113	(unsigned long long)dev->last_residency;
	114	dev->states_usage[entered_state].usage++;
	115	} else {
	116	dev->last_residency = 0;
	117	}
	118
	119	return entered_state;
	120	}
	121
4f86d3a8 LB	122	/**
	123	* cpuidle_idle_call - the main idle loop
	124	*
	125	* NOTE: no locks or semaphores should be used here
a0bfa137	126	* return non-zero on failure
4f86d3a8	127	*/
a0bfa137	128	int cpuidle_idle_call(void)
4f86d3a8	129	{
4a6f4fe8	130	struct cpuidle_device *dev = __this_cpu_read(cpuidle_devices);
46bcfad7	131	struct cpuidle_driver *drv = cpuidle_get_driver();
e978aa7d	132	int next_state, entered_state;
4f86d3a8	133
a0bfa137 LB	134	if (off)
	135	return -ENODEV;
	136
	137	if (!initialized)
	138	return -ENODEV;
	139
4f86d3a8	140	/* check if the device is ready */
a0bfa137 LB	141	if (!dev \|\| !dev->enabled)
a0bfa137 LB	142	return -EBUSY;
4f86d3a8 LB	143
4f86d3a8 LB	144	/* ask the governor for the next state */
46bcfad7	145	next_state = cpuidle_curr_governor->select(drv, dev);
246eb7f0 KH	146	if (need_resched()) {
246eb7f0 KH	147	local_irq_enable();
a0bfa137	148	return 0;
246eb7f0 KH	149	}
246eb7f0 KH	150
76027ea8 SR	151	trace_power_start_rcuidle(POWER_CSTATE, next_state, dev->cpu);
76027ea8 SR	152	trace_cpu_idle_rcuidle(next_state, dev->cpu);
f77cfe4e	153
4126c019 CC	154	if (cpuidle_state_is_coupled(dev, drv, next_state))
	155	entered_state = cpuidle_enter_state_coupled(dev, drv,
	156	next_state);
	157	else
	158	entered_state = cpuidle_enter_state(dev, drv, next_state);
f77cfe4e	159
76027ea8 SR	160	trace_power_end_rcuidle(dev->cpu);
76027ea8 SR	161	trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, dev->cpu);
f77cfe4e	162
4f86d3a8 LB	163	/* give the governor an opportunity to reflect on the outcome */
4f86d3a8 LB	164	if (cpuidle_curr_governor->reflect)
e978aa7d	165	cpuidle_curr_governor->reflect(dev, entered_state);
a0bfa137 LB	166
a0bfa137 LB	167	return 0;
4f86d3a8 LB	168	}
	169
	170	/**
	171	* cpuidle_install_idle_handler - installs the cpuidle idle loop handler
	172	*/
	173	void cpuidle_install_idle_handler(void)
	174	{
a0bfa137	175	if (enabled_devices) {
4f86d3a8 LB	176	/* Make sure all changes finished before we switch to new idle */
4f86d3a8 LB	177	smp_wmb();
a0bfa137	178	initialized = 1;
4f86d3a8 LB	179	}
	180	}
	181
	182	/**
	183	* cpuidle_uninstall_idle_handler - uninstalls the cpuidle idle loop handler
	184	*/
	185	void cpuidle_uninstall_idle_handler(void)
	186	{
a0bfa137 LB	187	if (enabled_devices) {
a0bfa137 LB	188	initialized = 0;
4a162513	189	kick_all_cpus_sync();
4f86d3a8 LB	190	}
	191	}
	192
	193	/**
	194	* cpuidle_pause_and_lock - temporarily disables CPUIDLE
	195	*/
	196	void cpuidle_pause_and_lock(void)
	197	{
	198	mutex_lock(&cpuidle_lock);
	199	cpuidle_uninstall_idle_handler();
	200	}
	201
	202	EXPORT_SYMBOL_GPL(cpuidle_pause_and_lock);
	203
	204	/**
	205	* cpuidle_resume_and_unlock - resumes CPUIDLE operation
	206	*/
	207	void cpuidle_resume_and_unlock(void)
	208	{
	209	cpuidle_install_idle_handler();
	210	mutex_unlock(&cpuidle_lock);
	211	}
	212
	213	EXPORT_SYMBOL_GPL(cpuidle_resume_and_unlock);
	214
8651f97b PM	215	/* Currently used in suspend/resume path to suspend cpuidle */
	216	void cpuidle_pause(void)
	217	{
	218	mutex_lock(&cpuidle_lock);
	219	cpuidle_uninstall_idle_handler();
	220	mutex_unlock(&cpuidle_lock);
	221	}
	222
	223	/* Currently used in suspend/resume path to resume cpuidle */
	224	void cpuidle_resume(void)
	225	{
	226	mutex_lock(&cpuidle_lock);
	227	cpuidle_install_idle_handler();
	228	mutex_unlock(&cpuidle_lock);
	229	}
	230
e1689795 RL	231	/**
	232	* cpuidle_wrap_enter - performs timekeeping and irqen around enter function
	233	* @dev: pointer to a valid cpuidle_device object
	234	* @drv: pointer to a valid cpuidle_driver object
	235	* @index: index of the target cpuidle state.
	236	*/
	237	int cpuidle_wrap_enter(struct cpuidle_device *dev,
	238	struct cpuidle_driver *drv, int index,
	239	int (enter)(struct cpuidle_device dev,
	240	struct cpuidle_driver *drv, int index))
	241	{
	242	ktime_t time_start, time_end;
	243	s64 diff;
	244
	245	time_start = ktime_get();
	246
	247	index = enter(dev, drv, index);
	248
	249	time_end = ktime_get();
	250
	251	local_irq_enable();
	252
	253	diff = ktime_to_us(ktime_sub(time_end, time_start));
	254	if (diff > INT_MAX)
	255	diff = INT_MAX;
	256
	257	dev->last_residency = (int) diff;
	258
	259	return index;
	260	}
	261
d8c216cf	262	#ifdef CONFIG_ARCH_HAS_CPU_RELAX
46bcfad7 DD	263	static int poll_idle(struct cpuidle_device *dev,
46bcfad7 DD	264	struct cpuidle_driver *drv, int index)
d8c216cf RW	265	{
	266	ktime_t t1, t2;
	267	s64 diff;
d8c216cf RW	268
	269	t1 = ktime_get();
	270	local_irq_enable();
	271	while (!need_resched())
	272	cpu_relax();
	273
	274	t2 = ktime_get();
	275	diff = ktime_to_us(ktime_sub(t2, t1));
	276	if (diff > INT_MAX)
	277	diff = INT_MAX;
	278
e978aa7d DD	279	dev->last_residency = (int) diff;
	280
	281	return index;
d8c216cf RW	282	}
d8c216cf RW	283
46bcfad7	284	static void poll_idle_init(struct cpuidle_driver *drv)
d8c216cf	285	{
46bcfad7	286	struct cpuidle_state *state = &drv->states[0];
d8c216cf	287
720f1c30	288	snprintf(state->name, CPUIDLE_NAME_LEN, "POLL");
d8c216cf RW	289	snprintf(state->desc, CPUIDLE_DESC_LEN, "CPUIDLE CORE POLL IDLE");
	290	state->exit_latency = 0;
	291	state->target_residency = 0;
	292	state->power_usage = -1;
d247632c	293	state->flags = 0;
d8c216cf	294	state->enter = poll_idle;
cbc9ef02	295	state->disabled = false;
d8c216cf RW	296	}
d8c216cf RW	297	#else
46bcfad7	298	static void poll_idle_init(struct cpuidle_driver *drv) {}
d8c216cf RW	299	#endif /* CONFIG_ARCH_HAS_CPU_RELAX */
d8c216cf RW	300
4f86d3a8 LB	301	/**
	302	* cpuidle_enable_device - enables idle PM for a CPU
	303	* @dev: the CPU
	304	*
	305	* This function must be called between cpuidle_pause_and_lock and
	306	* cpuidle_resume_and_unlock when used externally.
	307	*/
	308	int cpuidle_enable_device(struct cpuidle_device *dev)
	309	{
	310	int ret, i;
e1689795	311	struct cpuidle_driver *drv = cpuidle_get_driver();
4f86d3a8	312
1b0a0e9a SB	313	if (!dev)
	314	return -EINVAL;
	315
4f86d3a8 LB	316	if (dev->enabled)
4f86d3a8 LB	317	return 0;
e1689795	318	if (!drv \|\| !cpuidle_curr_governor)
4f86d3a8 LB	319	return -EIO;
4f86d3a8 LB	320	if (!dev->state_count)
fc850f39	321	dev->state_count = drv->state_count;
4f86d3a8	322
dcb84f33 VP	323	if (dev->registered == 0) {
	324	ret = __cpuidle_register_device(dev);
	325	if (ret)
	326	return ret;
	327	}
	328
e1689795 RL	329	cpuidle_enter_ops = drv->en_core_tk_irqen ?
	330	cpuidle_enter_tk : cpuidle_enter;
	331
	332	poll_idle_init(drv);
d8c216cf	333
4f86d3a8 LB	334	if ((ret = cpuidle_add_state_sysfs(dev)))
	335	return ret;
	336
	337	if (cpuidle_curr_governor->enable &&
e1689795	338	(ret = cpuidle_curr_governor->enable(drv, dev)))
4f86d3a8 LB	339	goto fail_sysfs;
	340
	341	for (i = 0; i < dev->state_count; i++) {
4202735e DD	342	dev->states_usage[i].usage = 0;
4202735e DD	343	dev->states_usage[i].time = 0;
4f86d3a8 LB	344	}
4f86d3a8 LB	345	dev->last_residency = 0;
4f86d3a8 LB	346
	347	smp_wmb();
	348
	349	dev->enabled = 1;
	350
	351	enabled_devices++;
	352	return 0;
	353
	354	fail_sysfs:
	355	cpuidle_remove_state_sysfs(dev);
	356
	357	return ret;
	358	}
	359
	360	EXPORT_SYMBOL_GPL(cpuidle_enable_device);
	361
	362	/**
	363	* cpuidle_disable_device - disables idle PM for a CPU
	364	* @dev: the CPU
	365	*
	366	* This function must be called between cpuidle_pause_and_lock and
	367	* cpuidle_resume_and_unlock when used externally.
	368	*/
	369	void cpuidle_disable_device(struct cpuidle_device *dev)
	370	{
cf31cd1a	371	if (!dev \|\| !dev->enabled)
4f86d3a8	372	return;
752138df	373	if (!cpuidle_get_driver() \|\| !cpuidle_curr_governor)
4f86d3a8 LB	374	return;
	375
	376	dev->enabled = 0;
	377
	378	if (cpuidle_curr_governor->disable)
46bcfad7	379	cpuidle_curr_governor->disable(cpuidle_get_driver(), dev);
4f86d3a8 LB	380
	381	cpuidle_remove_state_sysfs(dev);
	382	enabled_devices--;
	383	}
	384
	385	EXPORT_SYMBOL_GPL(cpuidle_disable_device);
	386
	387	/**
dcb84f33 VP	388	* __cpuidle_register_device - internal register function called before register
dcb84f33 VP	389	* and enable routines
4f86d3a8	390	* @dev: the cpu
dcb84f33 VP	391	*
dcb84f33 VP	392	* cpuidle_lock mutex must be held before this is called
4f86d3a8	393	*/
dcb84f33	394	static int __cpuidle_register_device(struct cpuidle_device *dev)
4f86d3a8 LB	395	{
4f86d3a8 LB	396	int ret;
8a25a2fd	397	struct device *cpu_dev = get_cpu_device((unsigned long)dev->cpu);
752138df	398	struct cpuidle_driver *cpuidle_driver = cpuidle_get_driver();
4f86d3a8	399
752138df	400	if (!try_module_get(cpuidle_driver->owner))
4f86d3a8 LB	401	return -EINVAL;
	402
	403	init_completion(&dev->kobj_unregister);
	404
4f86d3a8 LB	405	per_cpu(cpuidle_devices, dev->cpu) = dev;
4f86d3a8 LB	406	list_add(&dev->device_list, &cpuidle_detected_devices);
3af272ab CC	407	ret = cpuidle_add_sysfs(cpu_dev);
	408	if (ret)
	409	goto err_sysfs;
4f86d3a8	410
4126c019 CC	411	ret = cpuidle_coupled_register_device(dev);
	412	if (ret)
	413	goto err_coupled;
4f86d3a8	414
dcb84f33 VP	415	dev->registered = 1;
dcb84f33 VP	416	return 0;
3af272ab	417
4126c019 CC	418	err_coupled:
	419	cpuidle_remove_sysfs(cpu_dev);
	420	wait_for_completion(&dev->kobj_unregister);
3af272ab CC	421	err_sysfs:
	422	list_del(&dev->device_list);
	423	per_cpu(cpuidle_devices, dev->cpu) = NULL;
	424	module_put(cpuidle_driver->owner);
	425	return ret;
dcb84f33 VP	426	}
	427
	428	/**
	429	* cpuidle_register_device - registers a CPU's idle PM feature
	430	* @dev: the cpu
	431	*/
	432	int cpuidle_register_device(struct cpuidle_device *dev)
	433	{
	434	int ret;
	435
1b0a0e9a SB	436	if (!dev)
	437	return -EINVAL;
	438
dcb84f33 VP	439	mutex_lock(&cpuidle_lock);
	440
	441	if ((ret = __cpuidle_register_device(dev))) {
	442	mutex_unlock(&cpuidle_lock);
	443	return ret;
	444	}
	445
4f86d3a8 LB	446	cpuidle_enable_device(dev);
	447	cpuidle_install_idle_handler();
	448
	449	mutex_unlock(&cpuidle_lock);
	450
	451	return 0;
	452
	453	}
	454
	455	EXPORT_SYMBOL_GPL(cpuidle_register_device);
	456
	457	/**
	458	* cpuidle_unregister_device - unregisters a CPU's idle PM feature
	459	* @dev: the cpu
	460	*/
	461	void cpuidle_unregister_device(struct cpuidle_device *dev)
	462	{
8a25a2fd	463	struct device *cpu_dev = get_cpu_device((unsigned long)dev->cpu);
752138df	464	struct cpuidle_driver *cpuidle_driver = cpuidle_get_driver();
4f86d3a8	465
dcb84f33 VP	466	if (dev->registered == 0)
	467	return;
	468
4f86d3a8 LB	469	cpuidle_pause_and_lock();
	470
	471	cpuidle_disable_device(dev);
	472
8a25a2fd	473	cpuidle_remove_sysfs(cpu_dev);
4f86d3a8 LB	474	list_del(&dev->device_list);
	475	wait_for_completion(&dev->kobj_unregister);
	476	per_cpu(cpuidle_devices, dev->cpu) = NULL;
	477
4126c019 CC	478	cpuidle_coupled_unregister_device(dev);
4126c019 CC	479
4f86d3a8 LB	480	cpuidle_resume_and_unlock();
4f86d3a8 LB	481
752138df	482	module_put(cpuidle_driver->owner);
4f86d3a8 LB	483	}
	484
	485	EXPORT_SYMBOL_GPL(cpuidle_unregister_device);
	486
	487	#ifdef CONFIG_SMP
	488
	489	static void smp_callback(void *v)
	490	{
	491	/* we already woke the CPU up, nothing more to do */
	492	}
	493
	494	/*
	495	* This function gets called when a part of the kernel has a new latency
	496	* requirement. This means we need to get all processors out of their C-state,
	497	* and then recalculate a new suitable C-state. Just do a cross-cpu IPI; that
	498	* wakes them all right up.
	499	*/
	500	static int cpuidle_latency_notify(struct notifier_block *b,
	501	unsigned long l, void *v)
	502	{
8691e5a8	503	smp_call_function(smp_callback, NULL, 1);
4f86d3a8 LB	504	return NOTIFY_OK;
	505	}
	506
	507	static struct notifier_block cpuidle_latency_notifier = {
	508	.notifier_call = cpuidle_latency_notify,
	509	};
	510
d82b3518 MG	511	static inline void latency_notifier_init(struct notifier_block *n)
	512	{
	513	pm_qos_add_notifier(PM_QOS_CPU_DMA_LATENCY, n);
	514	}
4f86d3a8 LB	515
	516	#else /* CONFIG_SMP */
	517
	518	#define latency_notifier_init(x) do { } while (0)
	519
	520	#endif /* CONFIG_SMP */
	521
	522	/**
	523	* cpuidle_init - core initializer
	524	*/
	525	static int __init cpuidle_init(void)
	526	{
	527	int ret;
	528
62027aea LB	529	if (cpuidle_disabled())
	530	return -ENODEV;
	531
8a25a2fd	532	ret = cpuidle_add_interface(cpu_subsys.dev_root);
4f86d3a8 LB	533	if (ret)
	534	return ret;
	535
	536	latency_notifier_init(&cpuidle_latency_notifier);
	537
	538	return 0;
	539	}
	540
62027aea	541	module_param(off, int, 0444);
4f86d3a8	542	core_initcall(cpuidle_init);