[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_cpu_driver(dev);
	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;
	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;

	drv = cpuidle_get_cpu_driver(dev);

	/* ask the governor for the next state */
	next_state = cpuidle_curr_governor->select(drv, dev);
	if (need_resched()) {
		dev->last_residency = 0;
		/* give the governor an opportunity to reflect on the outcome */
		if (cpuidle_curr_governor->reflect)
			cpuidle_curr_governor->reflect(dev, next_state);
		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;

	if (!dev)
		return -EINVAL;

	if (dev->enabled)
		return 0;

	drv = cpuidle_get_cpu_driver(dev);

	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);

	ret = cpuidle_add_device_sysfs(dev);
	if (ret)
		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_device_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)
{
	struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);

	if (!dev || !dev->enabled)
		return;

	if (!drv || !cpuidle_curr_governor)
		return;

	dev->enabled = 0;

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

	cpuidle_remove_device_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 cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);

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

	per_cpu(cpuidle_devices, dev->cpu) = dev;
	list_add(&dev->device_list, &cpuidle_detected_devices);
	ret = cpuidle_add_sysfs(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(dev);
err_sysfs:
	list_del(&dev->device_list);
	per_cpu(cpuidle_devices, dev->cpu) = NULL;
	module_put(drv->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 cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);

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

	cpuidle_pause_and_lock();

	cpuidle_disable_device(dev);

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

	cpuidle_coupled_unregister_device(dev);

	cpuidle_resume_and_unlock();

	module_put(drv->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);
bf4d1b5d	71	struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);
1a022e3f BO	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);
bf4d1b5d	131	struct cpuidle_driver *drv;
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	143
bf4d1b5d DL	144	drv = cpuidle_get_cpu_driver(dev);
bf4d1b5d DL	145
4f86d3a8	146	/* ask the governor for the next state */
46bcfad7	147	next_state = cpuidle_curr_governor->select(drv, dev);
246eb7f0	148	if (need_resched()) {
d73d68dc YS	149	dev->last_residency = 0;
	150	/* give the governor an opportunity to reflect on the outcome */
	151	if (cpuidle_curr_governor->reflect)
	152	cpuidle_curr_governor->reflect(dev, next_state);
246eb7f0	153	local_irq_enable();
a0bfa137	154	return 0;
246eb7f0 KH	155	}
246eb7f0 KH	156
76027ea8 SR	157	trace_power_start_rcuidle(POWER_CSTATE, next_state, dev->cpu);
76027ea8 SR	158	trace_cpu_idle_rcuidle(next_state, dev->cpu);
f77cfe4e	159
4126c019 CC	160	if (cpuidle_state_is_coupled(dev, drv, next_state))
	161	entered_state = cpuidle_enter_state_coupled(dev, drv,
	162	next_state);
	163	else
	164	entered_state = cpuidle_enter_state(dev, drv, next_state);
f77cfe4e	165
76027ea8 SR	166	trace_power_end_rcuidle(dev->cpu);
76027ea8 SR	167	trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, dev->cpu);
f77cfe4e	168
4f86d3a8 LB	169	/* give the governor an opportunity to reflect on the outcome */
4f86d3a8 LB	170	if (cpuidle_curr_governor->reflect)
e978aa7d	171	cpuidle_curr_governor->reflect(dev, entered_state);
a0bfa137 LB	172
a0bfa137 LB	173	return 0;
4f86d3a8 LB	174	}
	175
	176	/**
	177	* cpuidle_install_idle_handler - installs the cpuidle idle loop handler
	178	*/
	179	void cpuidle_install_idle_handler(void)
	180	{
a0bfa137	181	if (enabled_devices) {
4f86d3a8 LB	182	/* Make sure all changes finished before we switch to new idle */
4f86d3a8 LB	183	smp_wmb();
a0bfa137	184	initialized = 1;
4f86d3a8 LB	185	}
	186	}
	187
	188	/**
	189	* cpuidle_uninstall_idle_handler - uninstalls the cpuidle idle loop handler
	190	*/
	191	void cpuidle_uninstall_idle_handler(void)
	192	{
a0bfa137 LB	193	if (enabled_devices) {
a0bfa137 LB	194	initialized = 0;
4a162513	195	kick_all_cpus_sync();
4f86d3a8 LB	196	}
	197	}
	198
	199	/**
	200	* cpuidle_pause_and_lock - temporarily disables CPUIDLE
	201	*/
	202	void cpuidle_pause_and_lock(void)
	203	{
	204	mutex_lock(&cpuidle_lock);
	205	cpuidle_uninstall_idle_handler();
	206	}
	207
	208	EXPORT_SYMBOL_GPL(cpuidle_pause_and_lock);
	209
	210	/**
	211	* cpuidle_resume_and_unlock - resumes CPUIDLE operation
	212	*/
	213	void cpuidle_resume_and_unlock(void)
	214	{
	215	cpuidle_install_idle_handler();
	216	mutex_unlock(&cpuidle_lock);
	217	}
	218
	219	EXPORT_SYMBOL_GPL(cpuidle_resume_and_unlock);
	220
8651f97b PM	221	/* Currently used in suspend/resume path to suspend cpuidle */
	222	void cpuidle_pause(void)
	223	{
	224	mutex_lock(&cpuidle_lock);
	225	cpuidle_uninstall_idle_handler();
	226	mutex_unlock(&cpuidle_lock);
	227	}
	228
	229	/* Currently used in suspend/resume path to resume cpuidle */
	230	void cpuidle_resume(void)
	231	{
	232	mutex_lock(&cpuidle_lock);
	233	cpuidle_install_idle_handler();
	234	mutex_unlock(&cpuidle_lock);
	235	}
	236
e1689795 RL	237	/**
	238	* cpuidle_wrap_enter - performs timekeeping and irqen around enter function
	239	* @dev: pointer to a valid cpuidle_device object
	240	* @drv: pointer to a valid cpuidle_driver object
	241	* @index: index of the target cpuidle state.
	242	*/
	243	int cpuidle_wrap_enter(struct cpuidle_device *dev,
	244	struct cpuidle_driver *drv, int index,
	245	int (enter)(struct cpuidle_device dev,
	246	struct cpuidle_driver *drv, int index))
	247	{
	248	ktime_t time_start, time_end;
	249	s64 diff;
	250
	251	time_start = ktime_get();
	252
	253	index = enter(dev, drv, index);
	254
	255	time_end = ktime_get();
	256
	257	local_irq_enable();
	258
	259	diff = ktime_to_us(ktime_sub(time_end, time_start));
	260	if (diff > INT_MAX)
	261	diff = INT_MAX;
	262
	263	dev->last_residency = (int) diff;
	264
	265	return index;
	266	}
	267
d8c216cf	268	#ifdef CONFIG_ARCH_HAS_CPU_RELAX
46bcfad7 DD	269	static int poll_idle(struct cpuidle_device *dev,
46bcfad7 DD	270	struct cpuidle_driver *drv, int index)
d8c216cf RW	271	{
	272	ktime_t t1, t2;
	273	s64 diff;
d8c216cf RW	274
	275	t1 = ktime_get();
	276	local_irq_enable();
	277	while (!need_resched())
	278	cpu_relax();
	279
	280	t2 = ktime_get();
	281	diff = ktime_to_us(ktime_sub(t2, t1));
	282	if (diff > INT_MAX)
	283	diff = INT_MAX;
	284
e978aa7d DD	285	dev->last_residency = (int) diff;
	286
	287	return index;
d8c216cf RW	288	}
d8c216cf RW	289
46bcfad7	290	static void poll_idle_init(struct cpuidle_driver *drv)
d8c216cf	291	{
46bcfad7	292	struct cpuidle_state *state = &drv->states[0];
d8c216cf	293
720f1c30	294	snprintf(state->name, CPUIDLE_NAME_LEN, "POLL");
d8c216cf RW	295	snprintf(state->desc, CPUIDLE_DESC_LEN, "CPUIDLE CORE POLL IDLE");
	296	state->exit_latency = 0;
	297	state->target_residency = 0;
	298	state->power_usage = -1;
d247632c	299	state->flags = 0;
d8c216cf	300	state->enter = poll_idle;
cbc9ef02	301	state->disabled = false;
d8c216cf RW	302	}
d8c216cf RW	303	#else
46bcfad7	304	static void poll_idle_init(struct cpuidle_driver *drv) {}
d8c216cf RW	305	#endif /* CONFIG_ARCH_HAS_CPU_RELAX */
d8c216cf RW	306
4f86d3a8 LB	307	/**
	308	* cpuidle_enable_device - enables idle PM for a CPU
	309	* @dev: the CPU
	310	*
	311	* This function must be called between cpuidle_pause_and_lock and
	312	* cpuidle_resume_and_unlock when used externally.
	313	*/
	314	int cpuidle_enable_device(struct cpuidle_device *dev)
	315	{
	316	int ret, i;
bf4d1b5d	317	struct cpuidle_driver *drv;
4f86d3a8	318
1b0a0e9a SB	319	if (!dev)
	320	return -EINVAL;
	321
4f86d3a8 LB	322	if (dev->enabled)
4f86d3a8 LB	323	return 0;
bf4d1b5d DL	324
	325	drv = cpuidle_get_cpu_driver(dev);
	326
e1689795	327	if (!drv \|\| !cpuidle_curr_governor)
4f86d3a8	328	return -EIO;
bf4d1b5d	329
4f86d3a8	330	if (!dev->state_count)
fc850f39	331	dev->state_count = drv->state_count;
4f86d3a8	332
dcb84f33 VP	333	if (dev->registered == 0) {
	334	ret = __cpuidle_register_device(dev);
	335	if (ret)
	336	return ret;
	337	}
	338
e1689795 RL	339	cpuidle_enter_ops = drv->en_core_tk_irqen ?
	340	cpuidle_enter_tk : cpuidle_enter;
	341
	342	poll_idle_init(drv);
d8c216cf	343
bf4d1b5d DL	344	ret = cpuidle_add_device_sysfs(dev);
bf4d1b5d DL	345	if (ret)
4f86d3a8 LB	346	return ret;
	347
	348	if (cpuidle_curr_governor->enable &&
e1689795	349	(ret = cpuidle_curr_governor->enable(drv, dev)))
4f86d3a8 LB	350	goto fail_sysfs;
	351
	352	for (i = 0; i < dev->state_count; i++) {
4202735e DD	353	dev->states_usage[i].usage = 0;
4202735e DD	354	dev->states_usage[i].time = 0;
4f86d3a8 LB	355	}
4f86d3a8 LB	356	dev->last_residency = 0;
4f86d3a8 LB	357
	358	smp_wmb();
	359
	360	dev->enabled = 1;
	361
	362	enabled_devices++;
	363	return 0;
	364
	365	fail_sysfs:
bf4d1b5d	366	cpuidle_remove_device_sysfs(dev);
4f86d3a8 LB	367
	368	return ret;
	369	}
	370
	371	EXPORT_SYMBOL_GPL(cpuidle_enable_device);
	372
	373	/**
	374	* cpuidle_disable_device - disables idle PM for a CPU
	375	* @dev: the CPU
	376	*
	377	* This function must be called between cpuidle_pause_and_lock and
	378	* cpuidle_resume_and_unlock when used externally.
	379	*/
	380	void cpuidle_disable_device(struct cpuidle_device *dev)
	381	{
bf4d1b5d DL	382	struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);
bf4d1b5d DL	383
cf31cd1a	384	if (!dev \|\| !dev->enabled)
4f86d3a8	385	return;
bf4d1b5d DL	386
bf4d1b5d DL	387	if (!drv \|\| !cpuidle_curr_governor)
4f86d3a8 LB	388	return;
	389
	390	dev->enabled = 0;
	391
	392	if (cpuidle_curr_governor->disable)
bf4d1b5d	393	cpuidle_curr_governor->disable(drv, dev);
4f86d3a8	394
bf4d1b5d	395	cpuidle_remove_device_sysfs(dev);
4f86d3a8 LB	396	enabled_devices--;
	397	}
	398
	399	EXPORT_SYMBOL_GPL(cpuidle_disable_device);
	400
	401	/**
dcb84f33 VP	402	* __cpuidle_register_device - internal register function called before register
dcb84f33 VP	403	* and enable routines
4f86d3a8	404	* @dev: the cpu
dcb84f33 VP	405	*
dcb84f33 VP	406	* cpuidle_lock mutex must be held before this is called
4f86d3a8	407	*/
dcb84f33	408	static int __cpuidle_register_device(struct cpuidle_device *dev)
4f86d3a8 LB	409	{
4f86d3a8 LB	410	int ret;
bf4d1b5d	411	struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);
4f86d3a8	412
bf4d1b5d	413	if (!try_module_get(drv->owner))
4f86d3a8 LB	414	return -EINVAL;
4f86d3a8 LB	415
4f86d3a8 LB	416	per_cpu(cpuidle_devices, dev->cpu) = dev;
4f86d3a8 LB	417	list_add(&dev->device_list, &cpuidle_detected_devices);
1aef40e2	418	ret = cpuidle_add_sysfs(dev);
3af272ab CC	419	if (ret)
3af272ab CC	420	goto err_sysfs;
4f86d3a8	421
4126c019 CC	422	ret = cpuidle_coupled_register_device(dev);
	423	if (ret)
	424	goto err_coupled;
4f86d3a8	425
dcb84f33 VP	426	dev->registered = 1;
dcb84f33 VP	427	return 0;
3af272ab	428
4126c019	429	err_coupled:
1aef40e2	430	cpuidle_remove_sysfs(dev);
3af272ab CC	431	err_sysfs:
	432	list_del(&dev->device_list);
	433	per_cpu(cpuidle_devices, dev->cpu) = NULL;
bf4d1b5d	434	module_put(drv->owner);
3af272ab	435	return ret;
dcb84f33 VP	436	}
	437
	438	/**
	439	* cpuidle_register_device - registers a CPU's idle PM feature
	440	* @dev: the cpu
	441	*/
	442	int cpuidle_register_device(struct cpuidle_device *dev)
	443	{
	444	int ret;
	445
1b0a0e9a SB	446	if (!dev)
	447	return -EINVAL;
	448
dcb84f33 VP	449	mutex_lock(&cpuidle_lock);
	450
	451	if ((ret = __cpuidle_register_device(dev))) {
	452	mutex_unlock(&cpuidle_lock);
	453	return ret;
	454	}
	455
4f86d3a8 LB	456	cpuidle_enable_device(dev);
	457	cpuidle_install_idle_handler();
	458
	459	mutex_unlock(&cpuidle_lock);
	460
	461	return 0;
	462
	463	}
	464
	465	EXPORT_SYMBOL_GPL(cpuidle_register_device);
	466
	467	/**
	468	* cpuidle_unregister_device - unregisters a CPU's idle PM feature
	469	* @dev: the cpu
	470	*/
	471	void cpuidle_unregister_device(struct cpuidle_device *dev)
	472	{
bf4d1b5d	473	struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);
4f86d3a8	474
dcb84f33 VP	475	if (dev->registered == 0)
	476	return;
	477
4f86d3a8 LB	478	cpuidle_pause_and_lock();
	479
	480	cpuidle_disable_device(dev);
	481
1aef40e2	482	cpuidle_remove_sysfs(dev);
4f86d3a8	483	list_del(&dev->device_list);
4f86d3a8 LB	484	per_cpu(cpuidle_devices, dev->cpu) = NULL;
4f86d3a8 LB	485
4126c019 CC	486	cpuidle_coupled_unregister_device(dev);
4126c019 CC	487
4f86d3a8 LB	488	cpuidle_resume_and_unlock();
4f86d3a8 LB	489
bf4d1b5d	490	module_put(drv->owner);
4f86d3a8 LB	491	}
	492
	493	EXPORT_SYMBOL_GPL(cpuidle_unregister_device);
	494
	495	#ifdef CONFIG_SMP
	496
	497	static void smp_callback(void *v)
	498	{
	499	/* we already woke the CPU up, nothing more to do */
	500	}
	501
	502	/*
	503	* This function gets called when a part of the kernel has a new latency
	504	* requirement. This means we need to get all processors out of their C-state,
	505	* and then recalculate a new suitable C-state. Just do a cross-cpu IPI; that
	506	* wakes them all right up.
	507	*/
	508	static int cpuidle_latency_notify(struct notifier_block *b,
	509	unsigned long l, void *v)
	510	{
8691e5a8	511	smp_call_function(smp_callback, NULL, 1);
4f86d3a8 LB	512	return NOTIFY_OK;
	513	}
	514
	515	static struct notifier_block cpuidle_latency_notifier = {
	516	.notifier_call = cpuidle_latency_notify,
	517	};
	518
d82b3518 MG	519	static inline void latency_notifier_init(struct notifier_block *n)
	520	{
	521	pm_qos_add_notifier(PM_QOS_CPU_DMA_LATENCY, n);
	522	}
4f86d3a8 LB	523
	524	#else /* CONFIG_SMP */
	525
	526	#define latency_notifier_init(x) do { } while (0)
	527
	528	#endif /* CONFIG_SMP */
	529
	530	/**
	531	* cpuidle_init - core initializer
	532	*/
	533	static int __init cpuidle_init(void)
	534	{
	535	int ret;
	536
62027aea LB	537	if (cpuidle_disabled())
	538	return -ENODEV;
	539
8a25a2fd	540	ret = cpuidle_add_interface(cpu_subsys.dev_root);
4f86d3a8 LB	541	if (ret)
	542	return ret;
	543
	544	latency_notifier_init(&cpuidle_latency_notifier);
	545
	546	return 0;
	547	}
	548
62027aea	549	module_param(off, int, 0444);
4f86d3a8	550	core_initcall(cpuidle_init);