[linux-2.6-block.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;
}

#if defined(CONFIG_ARCH_HAS_CPU_IDLE_WAIT)
static void cpuidle_kick_cpus(void)
{
	cpu_idle_wait();
}
#elif defined(CONFIG_SMP)
# error "Arch needs cpu_idle_wait() equivalent here"
#else /* !CONFIG_ARCH_HAS_CPU_IDLE_WAIT && !CONFIG_SMP */
static void cpuidle_kick_cpus(void) {}
#endif

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
 *
 * Only returns in case of an error
 */
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;

	/* 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_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;

#if 0
	/* shows regressions, re-enable for 2.6.29 */
	/*
	 * run any timers that can be run now, at this point
	 * before calculating the idle duration etc.
	 */
	hrtimer_peek_ahead_timers();
#endif

	/* 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);

	entered_state = cpuidle_enter_ops(dev, drv, next_state);

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

	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;
	}

	/* 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;
		cpuidle_kick_cpus();
	}
}

/**
 * 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);

/**
 * 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->disable = 0;
}
#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->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->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 (!dev)
		return -EINVAL;
	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);
	if ((ret = cpuidle_add_sysfs(cpu_dev))) {
		module_put(cpuidle_driver->owner);
		return ret;
	}

	dev->registered = 1;
	return 0;
}

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

	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_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
a6869cc4 VP	43	#if defined(CONFIG_ARCH_HAS_CPU_IDLE_WAIT)
	44	static void cpuidle_kick_cpus(void)
	45	{
	46	cpu_idle_wait();
	47	}
	48	#elif defined(CONFIG_SMP)
	49	# error "Arch needs cpu_idle_wait() equivalent here"
	50	#else /* !CONFIG_ARCH_HAS_CPU_IDLE_WAIT && !CONFIG_SMP */
	51	static void cpuidle_kick_cpus(void) {}
	52	#endif
	53
dcb84f33 VP	54	static int __cpuidle_register_device(struct cpuidle_device *dev);
dcb84f33 VP	55
e1689795 RL	56	static inline int cpuidle_enter(struct cpuidle_device *dev,
	57	struct cpuidle_driver *drv, int index)
	58	{
	59	struct cpuidle_state *target_state = &drv->states[index];
	60	return target_state->enter(dev, drv, index);
	61	}
	62
	63	static inline int cpuidle_enter_tk(struct cpuidle_device *dev,
	64	struct cpuidle_driver *drv, int index)
	65	{
	66	return cpuidle_wrap_enter(dev, drv, index, cpuidle_enter);
	67	}
	68
	69	typedef int (cpuidle_enter_t)(struct cpuidle_device dev,
	70	struct cpuidle_driver *drv, int index);
	71
	72	static cpuidle_enter_t cpuidle_enter_ops;
	73
1a022e3f BO	74	/**
	75	* cpuidle_play_dead - cpu off-lining
	76	*
	77	* Only returns in case of an error
	78	*/
	79	int cpuidle_play_dead(void)
	80	{
	81	struct cpuidle_device *dev = __this_cpu_read(cpuidle_devices);
	82	struct cpuidle_driver *drv = cpuidle_get_driver();
	83	int i, dead_state = -1;
	84	int power_usage = -1;
	85
	86	/* Find lowest-power state that supports long-term idle */
	87	for (i = CPUIDLE_DRIVER_STATE_START; i < drv->state_count; i++) {
	88	struct cpuidle_state *s = &drv->states[i];
	89
	90	if (s->power_usage < power_usage && s->enter_dead) {
	91	power_usage = s->power_usage;
	92	dead_state = i;
	93	}
	94	}
	95
	96	if (dead_state != -1)
	97	return drv->states[dead_state].enter_dead(dev, dead_state);
	98
	99	return -ENODEV;
	100	}
	101
4f86d3a8 LB	102	/**
	103	* cpuidle_idle_call - the main idle loop
	104	*
	105	* NOTE: no locks or semaphores should be used here
a0bfa137	106	* return non-zero on failure
4f86d3a8	107	*/
a0bfa137	108	int cpuidle_idle_call(void)
4f86d3a8	109	{
4a6f4fe8	110	struct cpuidle_device *dev = __this_cpu_read(cpuidle_devices);
46bcfad7	111	struct cpuidle_driver *drv = cpuidle_get_driver();
e978aa7d	112	int next_state, entered_state;
4f86d3a8	113
a0bfa137 LB	114	if (off)
	115	return -ENODEV;
	116
	117	if (!initialized)
	118	return -ENODEV;
	119
4f86d3a8	120	/* check if the device is ready */
a0bfa137 LB	121	if (!dev \|\| !dev->enabled)
a0bfa137 LB	122	return -EBUSY;
4f86d3a8	123
9a655837 AV	124	#if 0
9a655837 AV	125	/* shows regressions, re-enable for 2.6.29 */
2e94d1f7 AV	126	/*
	127	* run any timers that can be run now, at this point
	128	* before calculating the idle duration etc.
	129	*/
	130	hrtimer_peek_ahead_timers();
9a655837	131	#endif
71abbbf8	132
4f86d3a8	133	/* ask the governor for the next state */
46bcfad7	134	next_state = cpuidle_curr_governor->select(drv, dev);
246eb7f0 KH	135	if (need_resched()) {
246eb7f0 KH	136	local_irq_enable();
a0bfa137	137	return 0;
246eb7f0 KH	138	}
246eb7f0 KH	139
76027ea8 SR	140	trace_power_start_rcuidle(POWER_CSTATE, next_state, dev->cpu);
76027ea8 SR	141	trace_cpu_idle_rcuidle(next_state, dev->cpu);
f77cfe4e	142
e1689795	143	entered_state = cpuidle_enter_ops(dev, drv, next_state);
f77cfe4e	144
76027ea8 SR	145	trace_power_end_rcuidle(dev->cpu);
76027ea8 SR	146	trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, dev->cpu);
f77cfe4e	147
e978aa7d DD	148	if (entered_state >= 0) {
	149	/* Update cpuidle counters */
	150	/* This can be moved to within driver enter routine
	151	* but that results in multiple copies of same code.
	152	*/
4202735e	153	dev->states_usage[entered_state].time +=
e978aa7d	154	(unsigned long long)dev->last_residency;
4202735e	155	dev->states_usage[entered_state].usage++;
e1689795 RL	156	} else {
e1689795 RL	157	dev->last_residency = 0;
e978aa7d	158	}
4f86d3a8 LB	159
	160	/* give the governor an opportunity to reflect on the outcome */
	161	if (cpuidle_curr_governor->reflect)
e978aa7d	162	cpuidle_curr_governor->reflect(dev, entered_state);
a0bfa137 LB	163
a0bfa137 LB	164	return 0;
4f86d3a8 LB	165	}
	166
	167	/**
	168	* cpuidle_install_idle_handler - installs the cpuidle idle loop handler
	169	*/
	170	void cpuidle_install_idle_handler(void)
	171	{
a0bfa137	172	if (enabled_devices) {
4f86d3a8 LB	173	/* Make sure all changes finished before we switch to new idle */
4f86d3a8 LB	174	smp_wmb();
a0bfa137	175	initialized = 1;
4f86d3a8 LB	176	}
	177	}
	178
	179	/**
	180	* cpuidle_uninstall_idle_handler - uninstalls the cpuidle idle loop handler
	181	*/
	182	void cpuidle_uninstall_idle_handler(void)
	183	{
a0bfa137 LB	184	if (enabled_devices) {
a0bfa137 LB	185	initialized = 0;
a6869cc4	186	cpuidle_kick_cpus();
4f86d3a8 LB	187	}
	188	}
	189
	190	/**
	191	* cpuidle_pause_and_lock - temporarily disables CPUIDLE
	192	*/
	193	void cpuidle_pause_and_lock(void)
	194	{
	195	mutex_lock(&cpuidle_lock);
	196	cpuidle_uninstall_idle_handler();
	197	}
	198
	199	EXPORT_SYMBOL_GPL(cpuidle_pause_and_lock);
	200
	201	/**
	202	* cpuidle_resume_and_unlock - resumes CPUIDLE operation
	203	*/
	204	void cpuidle_resume_and_unlock(void)
	205	{
	206	cpuidle_install_idle_handler();
	207	mutex_unlock(&cpuidle_lock);
	208	}
	209
	210	EXPORT_SYMBOL_GPL(cpuidle_resume_and_unlock);
	211
e1689795 RL	212	/**
	213	* cpuidle_wrap_enter - performs timekeeping and irqen around enter function
	214	* @dev: pointer to a valid cpuidle_device object
	215	* @drv: pointer to a valid cpuidle_driver object
	216	* @index: index of the target cpuidle state.
	217	*/
	218	int cpuidle_wrap_enter(struct cpuidle_device *dev,
	219	struct cpuidle_driver *drv, int index,
	220	int (enter)(struct cpuidle_device dev,
	221	struct cpuidle_driver *drv, int index))
	222	{
	223	ktime_t time_start, time_end;
	224	s64 diff;
	225
	226	time_start = ktime_get();
	227
	228	index = enter(dev, drv, index);
	229
	230	time_end = ktime_get();
	231
	232	local_irq_enable();
	233
	234	diff = ktime_to_us(ktime_sub(time_end, time_start));
	235	if (diff > INT_MAX)
	236	diff = INT_MAX;
	237
	238	dev->last_residency = (int) diff;
	239
	240	return index;
	241	}
	242
d8c216cf	243	#ifdef CONFIG_ARCH_HAS_CPU_RELAX
46bcfad7 DD	244	static int poll_idle(struct cpuidle_device *dev,
46bcfad7 DD	245	struct cpuidle_driver *drv, int index)
d8c216cf RW	246	{
	247	ktime_t t1, t2;
	248	s64 diff;
d8c216cf RW	249
	250	t1 = ktime_get();
	251	local_irq_enable();
	252	while (!need_resched())
	253	cpu_relax();
	254
	255	t2 = ktime_get();
	256	diff = ktime_to_us(ktime_sub(t2, t1));
	257	if (diff > INT_MAX)
	258	diff = INT_MAX;
	259
e978aa7d DD	260	dev->last_residency = (int) diff;
	261
	262	return index;
d8c216cf RW	263	}
d8c216cf RW	264
46bcfad7	265	static void poll_idle_init(struct cpuidle_driver *drv)
d8c216cf	266	{
46bcfad7	267	struct cpuidle_state *state = &drv->states[0];
d8c216cf	268
720f1c30	269	snprintf(state->name, CPUIDLE_NAME_LEN, "POLL");
d8c216cf RW	270	snprintf(state->desc, CPUIDLE_DESC_LEN, "CPUIDLE CORE POLL IDLE");
	271	state->exit_latency = 0;
	272	state->target_residency = 0;
	273	state->power_usage = -1;
d247632c	274	state->flags = 0;
d8c216cf	275	state->enter = poll_idle;
3a53396b	276	state->disable = 0;
d8c216cf RW	277	}
d8c216cf RW	278	#else
46bcfad7	279	static void poll_idle_init(struct cpuidle_driver *drv) {}
d8c216cf RW	280	#endif /* CONFIG_ARCH_HAS_CPU_RELAX */
d8c216cf RW	281
4f86d3a8 LB	282	/**
	283	* cpuidle_enable_device - enables idle PM for a CPU
	284	* @dev: the CPU
	285	*
	286	* This function must be called between cpuidle_pause_and_lock and
	287	* cpuidle_resume_and_unlock when used externally.
	288	*/
	289	int cpuidle_enable_device(struct cpuidle_device *dev)
	290	{
	291	int ret, i;
e1689795	292	struct cpuidle_driver *drv = cpuidle_get_driver();
4f86d3a8 LB	293
	294	if (dev->enabled)
	295	return 0;
e1689795	296	if (!drv \|\| !cpuidle_curr_governor)
4f86d3a8 LB	297	return -EIO;
4f86d3a8 LB	298	if (!dev->state_count)
fc850f39	299	dev->state_count = drv->state_count;
4f86d3a8	300
dcb84f33 VP	301	if (dev->registered == 0) {
	302	ret = __cpuidle_register_device(dev);
	303	if (ret)
	304	return ret;
	305	}
	306
e1689795 RL	307	cpuidle_enter_ops = drv->en_core_tk_irqen ?
	308	cpuidle_enter_tk : cpuidle_enter;
	309
	310	poll_idle_init(drv);
d8c216cf	311
4f86d3a8 LB	312	if ((ret = cpuidle_add_state_sysfs(dev)))
	313	return ret;
	314
	315	if (cpuidle_curr_governor->enable &&
e1689795	316	(ret = cpuidle_curr_governor->enable(drv, dev)))
4f86d3a8 LB	317	goto fail_sysfs;
	318
	319	for (i = 0; i < dev->state_count; i++) {
4202735e DD	320	dev->states_usage[i].usage = 0;
4202735e DD	321	dev->states_usage[i].time = 0;
4f86d3a8 LB	322	}
4f86d3a8 LB	323	dev->last_residency = 0;
4f86d3a8 LB	324
	325	smp_wmb();
	326
	327	dev->enabled = 1;
	328
	329	enabled_devices++;
	330	return 0;
	331
	332	fail_sysfs:
	333	cpuidle_remove_state_sysfs(dev);
	334
	335	return ret;
	336	}
	337
	338	EXPORT_SYMBOL_GPL(cpuidle_enable_device);
	339
	340	/**
	341	* cpuidle_disable_device - disables idle PM for a CPU
	342	* @dev: the CPU
	343	*
	344	* This function must be called between cpuidle_pause_and_lock and
	345	* cpuidle_resume_and_unlock when used externally.
	346	*/
	347	void cpuidle_disable_device(struct cpuidle_device *dev)
	348	{
	349	if (!dev->enabled)
	350	return;
752138df	351	if (!cpuidle_get_driver() \|\| !cpuidle_curr_governor)
4f86d3a8 LB	352	return;
	353
	354	dev->enabled = 0;
	355
	356	if (cpuidle_curr_governor->disable)
46bcfad7	357	cpuidle_curr_governor->disable(cpuidle_get_driver(), dev);
4f86d3a8 LB	358
	359	cpuidle_remove_state_sysfs(dev);
	360	enabled_devices--;
	361	}
	362
	363	EXPORT_SYMBOL_GPL(cpuidle_disable_device);
	364
	365	/**
dcb84f33 VP	366	* __cpuidle_register_device - internal register function called before register
dcb84f33 VP	367	* and enable routines
4f86d3a8	368	* @dev: the cpu
dcb84f33 VP	369	*
dcb84f33 VP	370	* cpuidle_lock mutex must be held before this is called
4f86d3a8	371	*/
dcb84f33	372	static int __cpuidle_register_device(struct cpuidle_device *dev)
4f86d3a8 LB	373	{
4f86d3a8 LB	374	int ret;
8a25a2fd	375	struct device *cpu_dev = get_cpu_device((unsigned long)dev->cpu);
752138df	376	struct cpuidle_driver *cpuidle_driver = cpuidle_get_driver();
4f86d3a8	377
8a25a2fd	378	if (!dev)
4f86d3a8	379	return -EINVAL;
752138df	380	if (!try_module_get(cpuidle_driver->owner))
4f86d3a8 LB	381	return -EINVAL;
	382
	383	init_completion(&dev->kobj_unregister);
	384
4f86d3a8 LB	385	per_cpu(cpuidle_devices, dev->cpu) = dev;
4f86d3a8 LB	386	list_add(&dev->device_list, &cpuidle_detected_devices);
8a25a2fd	387	if ((ret = cpuidle_add_sysfs(cpu_dev))) {
752138df	388	module_put(cpuidle_driver->owner);
4f86d3a8 LB	389	return ret;
	390	}
	391
dcb84f33 VP	392	dev->registered = 1;
	393	return 0;
	394	}
	395
	396	/**
	397	* cpuidle_register_device - registers a CPU's idle PM feature
	398	* @dev: the cpu
	399	*/
	400	int cpuidle_register_device(struct cpuidle_device *dev)
	401	{
	402	int ret;
	403
	404	mutex_lock(&cpuidle_lock);
	405
	406	if ((ret = __cpuidle_register_device(dev))) {
	407	mutex_unlock(&cpuidle_lock);
	408	return ret;
	409	}
	410
4f86d3a8 LB	411	cpuidle_enable_device(dev);
	412	cpuidle_install_idle_handler();
	413
	414	mutex_unlock(&cpuidle_lock);
	415
	416	return 0;
	417
	418	}
	419
	420	EXPORT_SYMBOL_GPL(cpuidle_register_device);
	421
	422	/**
	423	* cpuidle_unregister_device - unregisters a CPU's idle PM feature
	424	* @dev: the cpu
	425	*/
	426	void cpuidle_unregister_device(struct cpuidle_device *dev)
	427	{
8a25a2fd	428	struct device *cpu_dev = get_cpu_device((unsigned long)dev->cpu);
752138df	429	struct cpuidle_driver *cpuidle_driver = cpuidle_get_driver();
4f86d3a8	430
dcb84f33 VP	431	if (dev->registered == 0)
	432	return;
	433
4f86d3a8 LB	434	cpuidle_pause_and_lock();
	435
	436	cpuidle_disable_device(dev);
	437
8a25a2fd	438	cpuidle_remove_sysfs(cpu_dev);
4f86d3a8 LB	439	list_del(&dev->device_list);
	440	wait_for_completion(&dev->kobj_unregister);
	441	per_cpu(cpuidle_devices, dev->cpu) = NULL;
	442
	443	cpuidle_resume_and_unlock();
	444
752138df	445	module_put(cpuidle_driver->owner);
4f86d3a8 LB	446	}
	447
	448	EXPORT_SYMBOL_GPL(cpuidle_unregister_device);
	449
	450	#ifdef CONFIG_SMP
	451
	452	static void smp_callback(void *v)
	453	{
	454	/* we already woke the CPU up, nothing more to do */
	455	}
	456
	457	/*
	458	* This function gets called when a part of the kernel has a new latency
	459	* requirement. This means we need to get all processors out of their C-state,
	460	* and then recalculate a new suitable C-state. Just do a cross-cpu IPI; that
	461	* wakes them all right up.
	462	*/
	463	static int cpuidle_latency_notify(struct notifier_block *b,
	464	unsigned long l, void *v)
	465	{
8691e5a8	466	smp_call_function(smp_callback, NULL, 1);
4f86d3a8 LB	467	return NOTIFY_OK;
	468	}
	469
	470	static struct notifier_block cpuidle_latency_notifier = {
	471	.notifier_call = cpuidle_latency_notify,
	472	};
	473
d82b3518 MG	474	static inline void latency_notifier_init(struct notifier_block *n)
	475	{
	476	pm_qos_add_notifier(PM_QOS_CPU_DMA_LATENCY, n);
	477	}
4f86d3a8 LB	478
	479	#else /* CONFIG_SMP */
	480
	481	#define latency_notifier_init(x) do { } while (0)
	482
	483	#endif /* CONFIG_SMP */
	484
	485	/**
	486	* cpuidle_init - core initializer
	487	*/
	488	static int __init cpuidle_init(void)
	489	{
	490	int ret;
	491
62027aea LB	492	if (cpuidle_disabled())
	493	return -ENODEV;
	494
8a25a2fd	495	ret = cpuidle_add_interface(cpu_subsys.dev_root);
4f86d3a8 LB	496	if (ret)
	497	return ret;
	498
	499	latency_notifier_init(&cpuidle_latency_notifier);
	500
	501	return 0;
	502	}
	503
62027aea	504	module_param(off, int, 0444);
4f86d3a8	505	core_initcall(cpuidle_init);