[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/clockchips.h>
#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);

/**
 * 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;

	if (!drv)
		return -ENODEV;

	/* Find lowest-power state that supports long-term idle */
	for (i = drv->state_count - 1; i >= CPUIDLE_DRIVER_STATE_START; i--)
		if (drv->states[i].enter_dead)
			return drv->states[i].enter_dead(dev, i);

	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 index)
{
	int entered_state;

	struct cpuidle_state *target_state = &drv->states[index];
	ktime_t time_start, time_end;
	s64 diff;

	time_start = ktime_get();

	entered_state = target_state->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;

	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 += 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_cpu_idle_rcuidle(next_state, dev->cpu);

	if (drv->states[next_state].flags & CPUIDLE_FLAG_TIMER_STOP)
		clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER,
				   &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);

	if (drv->states[next_state].flags & CPUIDLE_FLAG_TIMER_STOP)
		clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_EXIT,
				   &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);
}

#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;
	}

	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
b60e6a0e	11	#include <linux/clockchips.h>
4f86d3a8 LB	12	#include <linux/kernel.h>
	13	#include <linux/mutex.h>
	14	#include <linux/sched.h>
	15	#include <linux/notifier.h>
e8db0be1	16	#include <linux/pm_qos.h>
4f86d3a8 LB	17	#include <linux/cpu.h>
4f86d3a8 LB	18	#include <linux/cpuidle.h>
9a0b8415	19	#include <linux/ktime.h>
2e94d1f7	20	#include <linux/hrtimer.h>
884b17e1	21	#include <linux/module.h>
288f023e	22	#include <trace/events/power.h>
4f86d3a8 LB	23
	24	#include "cpuidle.h"
	25
	26	DEFINE_PER_CPU(struct cpuidle_device *, cpuidle_devices);
4f86d3a8 LB	27
	28	DEFINE_MUTEX(cpuidle_lock);
	29	LIST_HEAD(cpuidle_detected_devices);
4f86d3a8 LB	30
4f86d3a8 LB	31	static int enabled_devices;
62027aea	32	static int off __read_mostly;
a0bfa137	33	static int initialized __read_mostly;
62027aea LB	34
	35	int cpuidle_disabled(void)
	36	{
	37	return off;
	38	}
d91ee586 LB	39	void disable_cpuidle(void)
	40	{
	41	off = 1;
	42	}
4f86d3a8	43
dcb84f33 VP	44	static int __cpuidle_register_device(struct cpuidle_device *dev);
dcb84f33 VP	45
1a022e3f BO	46	/**
	47	* cpuidle_play_dead - cpu off-lining
	48	*
ee01e663	49	* Returns in case of an error or no driver
1a022e3f BO	50	*/
	51	int cpuidle_play_dead(void)
	52	{
	53	struct cpuidle_device *dev = __this_cpu_read(cpuidle_devices);
bf4d1b5d	54	struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);
8aef33a7	55	int i;
1a022e3f	56
ee01e663 TK	57	if (!drv)
	58	return -ENODEV;
	59
1a022e3f	60	/* Find lowest-power state that supports long-term idle */
8aef33a7 DL	61	for (i = drv->state_count - 1; i >= CPUIDLE_DRIVER_STATE_START; i--)
	62	if (drv->states[i].enter_dead)
	63	return drv->states[i].enter_dead(dev, i);
1a022e3f BO	64
	65	return -ENODEV;
	66	}
	67
56cfbf74 CC	68	/**
	69	* cpuidle_enter_state - enter the state and update stats
	70	* @dev: cpuidle device for this cpu
	71	* @drv: cpuidle driver for this cpu
	72	* @next_state: index into drv->states of the state to enter
	73	*/
	74	int cpuidle_enter_state(struct cpuidle_device dev, struct cpuidle_driver drv,
554c06ba	75	int index)
56cfbf74 CC	76	{
	77	int entered_state;
	78
554c06ba DL	79	struct cpuidle_state *target_state = &drv->states[index];
	80	ktime_t time_start, time_end;
	81	s64 diff;
	82
	83	time_start = ktime_get();
	84
	85	entered_state = target_state->enter(dev, drv, index);
	86
	87	time_end = ktime_get();
	88
	89	local_irq_enable();
	90
	91	diff = ktime_to_us(ktime_sub(time_end, time_start));
	92	if (diff > INT_MAX)
	93	diff = INT_MAX;
	94
	95	dev->last_residency = (int) diff;
56cfbf74 CC	96
	97	if (entered_state >= 0) {
	98	/* Update cpuidle counters */
	99	/* This can be moved to within driver enter routine
	100	* but that results in multiple copies of same code.
	101	*/
a474a515	102	dev->states_usage[entered_state].time += dev->last_residency;
56cfbf74 CC	103	dev->states_usage[entered_state].usage++;
	104	} else {
	105	dev->last_residency = 0;
	106	}
	107
	108	return entered_state;
	109	}
	110
4f86d3a8 LB	111	/**
	112	* cpuidle_idle_call - the main idle loop
	113	*
	114	* NOTE: no locks or semaphores should be used here
a0bfa137	115	* return non-zero on failure
4f86d3a8	116	*/
a0bfa137	117	int cpuidle_idle_call(void)
4f86d3a8	118	{
4a6f4fe8	119	struct cpuidle_device *dev = __this_cpu_read(cpuidle_devices);
bf4d1b5d	120	struct cpuidle_driver *drv;
e978aa7d	121	int next_state, entered_state;
4f86d3a8	122
a0bfa137 LB	123	if (off)
	124	return -ENODEV;
	125
	126	if (!initialized)
	127	return -ENODEV;
	128
4f86d3a8	129	/* check if the device is ready */
a0bfa137 LB	130	if (!dev \|\| !dev->enabled)
a0bfa137 LB	131	return -EBUSY;
4f86d3a8	132
bf4d1b5d DL	133	drv = cpuidle_get_cpu_driver(dev);
bf4d1b5d DL	134
4f86d3a8	135	/* ask the governor for the next state */
46bcfad7	136	next_state = cpuidle_curr_governor->select(drv, dev);
246eb7f0	137	if (need_resched()) {
d73d68dc YS	138	dev->last_residency = 0;
	139	/* give the governor an opportunity to reflect on the outcome */
	140	if (cpuidle_curr_governor->reflect)
	141	cpuidle_curr_governor->reflect(dev, next_state);
246eb7f0	142	local_irq_enable();
a0bfa137	143	return 0;
246eb7f0 KH	144	}
246eb7f0 KH	145
76027ea8	146	trace_cpu_idle_rcuidle(next_state, dev->cpu);
f77cfe4e	147
b60e6a0e DL	148	if (drv->states[next_state].flags & CPUIDLE_FLAG_TIMER_STOP)
	149	clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER,
	150	&dev->cpu);
	151
4126c019 CC	152	if (cpuidle_state_is_coupled(dev, drv, next_state))
	153	entered_state = cpuidle_enter_state_coupled(dev, drv,
	154	next_state);
	155	else
	156	entered_state = cpuidle_enter_state(dev, drv, next_state);
f77cfe4e	157
b60e6a0e DL	158	if (drv->states[next_state].flags & CPUIDLE_FLAG_TIMER_STOP)
	159	clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_EXIT,
	160	&dev->cpu);
	161
76027ea8	162	trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, dev->cpu);
f77cfe4e	163
4f86d3a8 LB	164	/* give the governor an opportunity to reflect on the outcome */
4f86d3a8 LB	165	if (cpuidle_curr_governor->reflect)
e978aa7d	166	cpuidle_curr_governor->reflect(dev, entered_state);
a0bfa137 LB	167
a0bfa137 LB	168	return 0;
4f86d3a8 LB	169	}
	170
	171	/**
	172	* cpuidle_install_idle_handler - installs the cpuidle idle loop handler
	173	*/
	174	void cpuidle_install_idle_handler(void)
	175	{
a0bfa137	176	if (enabled_devices) {
4f86d3a8 LB	177	/* Make sure all changes finished before we switch to new idle */
4f86d3a8 LB	178	smp_wmb();
a0bfa137	179	initialized = 1;
4f86d3a8 LB	180	}
	181	}
	182
	183	/**
	184	* cpuidle_uninstall_idle_handler - uninstalls the cpuidle idle loop handler
	185	*/
	186	void cpuidle_uninstall_idle_handler(void)
	187	{
a0bfa137 LB	188	if (enabled_devices) {
a0bfa137 LB	189	initialized = 0;
4a162513	190	kick_all_cpus_sync();
4f86d3a8 LB	191	}
	192	}
	193
	194	/**
	195	* cpuidle_pause_and_lock - temporarily disables CPUIDLE
	196	*/
	197	void cpuidle_pause_and_lock(void)
	198	{
	199	mutex_lock(&cpuidle_lock);
	200	cpuidle_uninstall_idle_handler();
	201	}
	202
	203	EXPORT_SYMBOL_GPL(cpuidle_pause_and_lock);
	204
	205	/**
	206	* cpuidle_resume_and_unlock - resumes CPUIDLE operation
	207	*/
	208	void cpuidle_resume_and_unlock(void)
	209	{
	210	cpuidle_install_idle_handler();
	211	mutex_unlock(&cpuidle_lock);
	212	}
	213
	214	EXPORT_SYMBOL_GPL(cpuidle_resume_and_unlock);
	215
8651f97b PM	216	/* Currently used in suspend/resume path to suspend cpuidle */
	217	void cpuidle_pause(void)
	218	{
	219	mutex_lock(&cpuidle_lock);
	220	cpuidle_uninstall_idle_handler();
	221	mutex_unlock(&cpuidle_lock);
	222	}
	223
	224	/* Currently used in suspend/resume path to resume cpuidle */
	225	void cpuidle_resume(void)
	226	{
	227	mutex_lock(&cpuidle_lock);
	228	cpuidle_install_idle_handler();
	229	mutex_unlock(&cpuidle_lock);
	230	}
	231
d8c216cf	232	#ifdef CONFIG_ARCH_HAS_CPU_RELAX
46bcfad7 DD	233	static int poll_idle(struct cpuidle_device *dev,
46bcfad7 DD	234	struct cpuidle_driver *drv, int index)
d8c216cf RW	235	{
	236	ktime_t t1, t2;
	237	s64 diff;
d8c216cf RW	238
	239	t1 = ktime_get();
	240	local_irq_enable();
	241	while (!need_resched())
	242	cpu_relax();
	243
	244	t2 = ktime_get();
	245	diff = ktime_to_us(ktime_sub(t2, t1));
	246	if (diff > INT_MAX)
	247	diff = INT_MAX;
	248
e978aa7d DD	249	dev->last_residency = (int) diff;
	250
	251	return index;
d8c216cf RW	252	}
d8c216cf RW	253
46bcfad7	254	static void poll_idle_init(struct cpuidle_driver *drv)
d8c216cf	255	{
46bcfad7	256	struct cpuidle_state *state = &drv->states[0];
d8c216cf	257
720f1c30	258	snprintf(state->name, CPUIDLE_NAME_LEN, "POLL");
d8c216cf RW	259	snprintf(state->desc, CPUIDLE_DESC_LEN, "CPUIDLE CORE POLL IDLE");
	260	state->exit_latency = 0;
	261	state->target_residency = 0;
	262	state->power_usage = -1;
d247632c	263	state->flags = 0;
d8c216cf	264	state->enter = poll_idle;
cbc9ef02	265	state->disabled = false;
d8c216cf RW	266	}
d8c216cf RW	267	#else
46bcfad7	268	static void poll_idle_init(struct cpuidle_driver *drv) {}
d8c216cf RW	269	#endif /* CONFIG_ARCH_HAS_CPU_RELAX */
d8c216cf RW	270
4f86d3a8 LB	271	/**
	272	* cpuidle_enable_device - enables idle PM for a CPU
	273	* @dev: the CPU
	274	*
	275	* This function must be called between cpuidle_pause_and_lock and
	276	* cpuidle_resume_and_unlock when used externally.
	277	*/
	278	int cpuidle_enable_device(struct cpuidle_device *dev)
	279	{
	280	int ret, i;
bf4d1b5d	281	struct cpuidle_driver *drv;
4f86d3a8	282
1b0a0e9a SB	283	if (!dev)
	284	return -EINVAL;
	285
4f86d3a8 LB	286	if (dev->enabled)
4f86d3a8 LB	287	return 0;
bf4d1b5d DL	288
	289	drv = cpuidle_get_cpu_driver(dev);
	290
e1689795	291	if (!drv \|\| !cpuidle_curr_governor)
4f86d3a8	292	return -EIO;
bf4d1b5d	293
4f86d3a8	294	if (!dev->state_count)
fc850f39	295	dev->state_count = drv->state_count;
4f86d3a8	296
dcb84f33 VP	297	if (dev->registered == 0) {
	298	ret = __cpuidle_register_device(dev);
	299	if (ret)
	300	return ret;
	301	}
	302
e1689795	303	poll_idle_init(drv);
d8c216cf	304
bf4d1b5d DL	305	ret = cpuidle_add_device_sysfs(dev);
bf4d1b5d DL	306	if (ret)
4f86d3a8 LB	307	return ret;
	308
	309	if (cpuidle_curr_governor->enable &&
e1689795	310	(ret = cpuidle_curr_governor->enable(drv, dev)))
4f86d3a8 LB	311	goto fail_sysfs;
	312
	313	for (i = 0; i < dev->state_count; i++) {
4202735e DD	314	dev->states_usage[i].usage = 0;
4202735e DD	315	dev->states_usage[i].time = 0;
4f86d3a8 LB	316	}
4f86d3a8 LB	317	dev->last_residency = 0;
4f86d3a8 LB	318
	319	smp_wmb();
	320
	321	dev->enabled = 1;
	322
	323	enabled_devices++;
	324	return 0;
	325
	326	fail_sysfs:
bf4d1b5d	327	cpuidle_remove_device_sysfs(dev);
4f86d3a8 LB	328
	329	return ret;
	330	}
	331
	332	EXPORT_SYMBOL_GPL(cpuidle_enable_device);
	333
	334	/**
	335	* cpuidle_disable_device - disables idle PM for a CPU
	336	* @dev: the CPU
	337	*
	338	* This function must be called between cpuidle_pause_and_lock and
	339	* cpuidle_resume_and_unlock when used externally.
	340	*/
	341	void cpuidle_disable_device(struct cpuidle_device *dev)
	342	{
bf4d1b5d DL	343	struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);
bf4d1b5d DL	344
cf31cd1a	345	if (!dev \|\| !dev->enabled)
4f86d3a8	346	return;
bf4d1b5d DL	347
bf4d1b5d DL	348	if (!drv \|\| !cpuidle_curr_governor)
4f86d3a8 LB	349	return;
	350
	351	dev->enabled = 0;
	352
	353	if (cpuidle_curr_governor->disable)
bf4d1b5d	354	cpuidle_curr_governor->disable(drv, dev);
4f86d3a8	355
bf4d1b5d	356	cpuidle_remove_device_sysfs(dev);
4f86d3a8 LB	357	enabled_devices--;
	358	}
	359
	360	EXPORT_SYMBOL_GPL(cpuidle_disable_device);
	361
	362	/**
dcb84f33 VP	363	* __cpuidle_register_device - internal register function called before register
dcb84f33 VP	364	* and enable routines
4f86d3a8	365	* @dev: the cpu
dcb84f33 VP	366	*
dcb84f33 VP	367	* cpuidle_lock mutex must be held before this is called
4f86d3a8	368	*/
dcb84f33	369	static int __cpuidle_register_device(struct cpuidle_device *dev)
4f86d3a8 LB	370	{
4f86d3a8 LB	371	int ret;
bf4d1b5d	372	struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);
4f86d3a8	373
bf4d1b5d	374	if (!try_module_get(drv->owner))
4f86d3a8 LB	375	return -EINVAL;
4f86d3a8 LB	376
4f86d3a8 LB	377	per_cpu(cpuidle_devices, dev->cpu) = dev;
4f86d3a8 LB	378	list_add(&dev->device_list, &cpuidle_detected_devices);
1aef40e2	379	ret = cpuidle_add_sysfs(dev);
3af272ab CC	380	if (ret)
3af272ab CC	381	goto err_sysfs;
4f86d3a8	382
4126c019 CC	383	ret = cpuidle_coupled_register_device(dev);
	384	if (ret)
	385	goto err_coupled;
4f86d3a8	386
dcb84f33 VP	387	dev->registered = 1;
dcb84f33 VP	388	return 0;
3af272ab	389
4126c019	390	err_coupled:
1aef40e2	391	cpuidle_remove_sysfs(dev);
3af272ab CC	392	err_sysfs:
	393	list_del(&dev->device_list);
	394	per_cpu(cpuidle_devices, dev->cpu) = NULL;
bf4d1b5d	395	module_put(drv->owner);
3af272ab	396	return ret;
dcb84f33 VP	397	}
	398
	399	/**
	400	* cpuidle_register_device - registers a CPU's idle PM feature
	401	* @dev: the cpu
	402	*/
	403	int cpuidle_register_device(struct cpuidle_device *dev)
	404	{
	405	int ret;
	406
1b0a0e9a SB	407	if (!dev)
	408	return -EINVAL;
	409
dcb84f33 VP	410	mutex_lock(&cpuidle_lock);
	411
	412	if ((ret = __cpuidle_register_device(dev))) {
	413	mutex_unlock(&cpuidle_lock);
	414	return ret;
	415	}
	416
4f86d3a8 LB	417	cpuidle_enable_device(dev);
	418	cpuidle_install_idle_handler();
	419
	420	mutex_unlock(&cpuidle_lock);
	421
	422	return 0;
	423
	424	}
	425
	426	EXPORT_SYMBOL_GPL(cpuidle_register_device);
	427
	428	/**
	429	* cpuidle_unregister_device - unregisters a CPU's idle PM feature
	430	* @dev: the cpu
	431	*/
	432	void cpuidle_unregister_device(struct cpuidle_device *dev)
	433	{
bf4d1b5d	434	struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);
4f86d3a8	435
dcb84f33 VP	436	if (dev->registered == 0)
	437	return;
	438
4f86d3a8 LB	439	cpuidle_pause_and_lock();
	440
	441	cpuidle_disable_device(dev);
	442
1aef40e2	443	cpuidle_remove_sysfs(dev);
4f86d3a8	444	list_del(&dev->device_list);
4f86d3a8 LB	445	per_cpu(cpuidle_devices, dev->cpu) = NULL;
4f86d3a8 LB	446
4126c019 CC	447	cpuidle_coupled_unregister_device(dev);
4126c019 CC	448
4f86d3a8 LB	449	cpuidle_resume_and_unlock();
4f86d3a8 LB	450
bf4d1b5d	451	module_put(drv->owner);
4f86d3a8 LB	452	}
	453
	454	EXPORT_SYMBOL_GPL(cpuidle_unregister_device);
	455
	456	#ifdef CONFIG_SMP
	457
	458	static void smp_callback(void *v)
	459	{
	460	/* we already woke the CPU up, nothing more to do */
	461	}
	462
	463	/*
	464	* This function gets called when a part of the kernel has a new latency
	465	* requirement. This means we need to get all processors out of their C-state,
	466	* and then recalculate a new suitable C-state. Just do a cross-cpu IPI; that
	467	* wakes them all right up.
	468	*/
	469	static int cpuidle_latency_notify(struct notifier_block *b,
	470	unsigned long l, void *v)
	471	{
8691e5a8	472	smp_call_function(smp_callback, NULL, 1);
4f86d3a8 LB	473	return NOTIFY_OK;
	474	}
	475
	476	static struct notifier_block cpuidle_latency_notifier = {
	477	.notifier_call = cpuidle_latency_notify,
	478	};
	479
d82b3518 MG	480	static inline void latency_notifier_init(struct notifier_block *n)
	481	{
	482	pm_qos_add_notifier(PM_QOS_CPU_DMA_LATENCY, n);
	483	}
4f86d3a8 LB	484
	485	#else /* CONFIG_SMP */
	486
	487	#define latency_notifier_init(x) do { } while (0)
	488
	489	#endif /* CONFIG_SMP */
	490
	491	/**
	492	* cpuidle_init - core initializer
	493	*/
	494	static int __init cpuidle_init(void)
	495	{
	496	int ret;
	497
62027aea LB	498	if (cpuidle_disabled())
	499	return -ENODEV;
	500
8a25a2fd	501	ret = cpuidle_add_interface(cpu_subsys.dev_root);
4f86d3a8 LB	502	if (ret)
	503	return ret;
	504
	505	latency_notifier_init(&cpuidle_latency_notifier);
	506
	507	return 0;
	508	}
	509
62027aea	510	module_param(off, int, 0444);
4f86d3a8	511	core_initcall(cpuidle_init);