[mirror_ubuntu-bionic-kernel.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
 *
 * 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_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	*
ee01e663	77	* Returns in case of an error or no driver
1a022e3f BO	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
ee01e663 TK	86	if (!drv)
	87	return -ENODEV;
	88
1a022e3f BO	89	/* Find lowest-power state that supports long-term idle */
	90	for (i = CPUIDLE_DRIVER_STATE_START; i < drv->state_count; i++) {
	91	struct cpuidle_state *s = &drv->states[i];
	92
	93	if (s->power_usage < power_usage && s->enter_dead) {
	94	power_usage = s->power_usage;
	95	dead_state = i;
	96	}
	97	}
	98
	99	if (dead_state != -1)
	100	return drv->states[dead_state].enter_dead(dev, dead_state);
	101
	102	return -ENODEV;
	103	}
	104
4f86d3a8 LB	105	/**
	106	* cpuidle_idle_call - the main idle loop
	107	*
	108	* NOTE: no locks or semaphores should be used here
a0bfa137	109	* return non-zero on failure
4f86d3a8	110	*/
a0bfa137	111	int cpuidle_idle_call(void)
4f86d3a8	112	{
4a6f4fe8	113	struct cpuidle_device *dev = __this_cpu_read(cpuidle_devices);
46bcfad7	114	struct cpuidle_driver *drv = cpuidle_get_driver();
e978aa7d	115	int next_state, entered_state;
4f86d3a8	116
a0bfa137 LB	117	if (off)
	118	return -ENODEV;
	119
	120	if (!initialized)
	121	return -ENODEV;
	122
4f86d3a8	123	/* check if the device is ready */
a0bfa137 LB	124	if (!dev \|\| !dev->enabled)
a0bfa137 LB	125	return -EBUSY;
4f86d3a8	126
9a655837 AV	127	#if 0
9a655837 AV	128	/* shows regressions, re-enable for 2.6.29 */
2e94d1f7 AV	129	/*
	130	* run any timers that can be run now, at this point
	131	* before calculating the idle duration etc.
	132	*/
	133	hrtimer_peek_ahead_timers();
9a655837	134	#endif
71abbbf8	135
4f86d3a8	136	/* ask the governor for the next state */
46bcfad7	137	next_state = cpuidle_curr_governor->select(drv, dev);
246eb7f0 KH	138	if (need_resched()) {
246eb7f0 KH	139	local_irq_enable();
a0bfa137	140	return 0;
246eb7f0 KH	141	}
246eb7f0 KH	142
76027ea8 SR	143	trace_power_start_rcuidle(POWER_CSTATE, next_state, dev->cpu);
76027ea8 SR	144	trace_cpu_idle_rcuidle(next_state, dev->cpu);
f77cfe4e	145
e1689795	146	entered_state = cpuidle_enter_ops(dev, drv, next_state);
f77cfe4e	147
76027ea8 SR	148	trace_power_end_rcuidle(dev->cpu);
76027ea8 SR	149	trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, dev->cpu);
f77cfe4e	150
e978aa7d DD	151	if (entered_state >= 0) {
	152	/* Update cpuidle counters */
	153	/* This can be moved to within driver enter routine
	154	* but that results in multiple copies of same code.
	155	*/
4202735e	156	dev->states_usage[entered_state].time +=
e978aa7d	157	(unsigned long long)dev->last_residency;
4202735e	158	dev->states_usage[entered_state].usage++;
e1689795 RL	159	} else {
e1689795 RL	160	dev->last_residency = 0;
e978aa7d	161	}
4f86d3a8 LB	162
	163	/* give the governor an opportunity to reflect on the outcome */
	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;
a6869cc4	189	cpuidle_kick_cpus();
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
e1689795 RL	215	/**
	216	* cpuidle_wrap_enter - performs timekeeping and irqen around enter function
	217	* @dev: pointer to a valid cpuidle_device object
	218	* @drv: pointer to a valid cpuidle_driver object
	219	* @index: index of the target cpuidle state.
	220	*/
	221	int cpuidle_wrap_enter(struct cpuidle_device *dev,
	222	struct cpuidle_driver *drv, int index,
	223	int (enter)(struct cpuidle_device dev,
	224	struct cpuidle_driver *drv, int index))
	225	{
	226	ktime_t time_start, time_end;
	227	s64 diff;
	228
	229	time_start = ktime_get();
	230
	231	index = enter(dev, drv, index);
	232
	233	time_end = ktime_get();
	234
	235	local_irq_enable();
	236
	237	diff = ktime_to_us(ktime_sub(time_end, time_start));
	238	if (diff > INT_MAX)
	239	diff = INT_MAX;
	240
	241	dev->last_residency = (int) diff;
	242
	243	return index;
	244	}
	245
d8c216cf	246	#ifdef CONFIG_ARCH_HAS_CPU_RELAX
46bcfad7 DD	247	static int poll_idle(struct cpuidle_device *dev,
46bcfad7 DD	248	struct cpuidle_driver *drv, int index)
d8c216cf RW	249	{
	250	ktime_t t1, t2;
	251	s64 diff;
d8c216cf RW	252
	253	t1 = ktime_get();
	254	local_irq_enable();
	255	while (!need_resched())
	256	cpu_relax();
	257
	258	t2 = ktime_get();
	259	diff = ktime_to_us(ktime_sub(t2, t1));
	260	if (diff > INT_MAX)
	261	diff = INT_MAX;
	262
e978aa7d DD	263	dev->last_residency = (int) diff;
	264
	265	return index;
d8c216cf RW	266	}
d8c216cf RW	267
46bcfad7	268	static void poll_idle_init(struct cpuidle_driver *drv)
d8c216cf	269	{
46bcfad7	270	struct cpuidle_state *state = &drv->states[0];
d8c216cf	271
720f1c30	272	snprintf(state->name, CPUIDLE_NAME_LEN, "POLL");
d8c216cf RW	273	snprintf(state->desc, CPUIDLE_DESC_LEN, "CPUIDLE CORE POLL IDLE");
	274	state->exit_latency = 0;
	275	state->target_residency = 0;
	276	state->power_usage = -1;
d247632c	277	state->flags = 0;
d8c216cf	278	state->enter = poll_idle;
3a53396b	279	state->disable = 0;
d8c216cf RW	280	}
d8c216cf RW	281	#else
46bcfad7	282	static void poll_idle_init(struct cpuidle_driver *drv) {}
d8c216cf RW	283	#endif /* CONFIG_ARCH_HAS_CPU_RELAX */
d8c216cf RW	284
4f86d3a8 LB	285	/**
	286	* cpuidle_enable_device - enables idle PM for a CPU
	287	* @dev: the CPU
	288	*
	289	* This function must be called between cpuidle_pause_and_lock and
	290	* cpuidle_resume_and_unlock when used externally.
	291	*/
	292	int cpuidle_enable_device(struct cpuidle_device *dev)
	293	{
	294	int ret, i;
e1689795	295	struct cpuidle_driver *drv = cpuidle_get_driver();
4f86d3a8 LB	296
	297	if (dev->enabled)
	298	return 0;
e1689795	299	if (!drv \|\| !cpuidle_curr_governor)
4f86d3a8 LB	300	return -EIO;
4f86d3a8 LB	301	if (!dev->state_count)
fc850f39	302	dev->state_count = drv->state_count;
4f86d3a8	303
dcb84f33 VP	304	if (dev->registered == 0) {
	305	ret = __cpuidle_register_device(dev);
	306	if (ret)
	307	return ret;
	308	}
	309
e1689795 RL	310	cpuidle_enter_ops = drv->en_core_tk_irqen ?
	311	cpuidle_enter_tk : cpuidle_enter;
	312
	313	poll_idle_init(drv);
d8c216cf	314
4f86d3a8 LB	315	if ((ret = cpuidle_add_state_sysfs(dev)))
	316	return ret;
	317
	318	if (cpuidle_curr_governor->enable &&
e1689795	319	(ret = cpuidle_curr_governor->enable(drv, dev)))
4f86d3a8 LB	320	goto fail_sysfs;
	321
	322	for (i = 0; i < dev->state_count; i++) {
4202735e DD	323	dev->states_usage[i].usage = 0;
4202735e DD	324	dev->states_usage[i].time = 0;
4f86d3a8 LB	325	}
4f86d3a8 LB	326	dev->last_residency = 0;
4f86d3a8 LB	327
	328	smp_wmb();
	329
	330	dev->enabled = 1;
	331
	332	enabled_devices++;
	333	return 0;
	334
	335	fail_sysfs:
	336	cpuidle_remove_state_sysfs(dev);
	337
	338	return ret;
	339	}
	340
	341	EXPORT_SYMBOL_GPL(cpuidle_enable_device);
	342
	343	/**
	344	* cpuidle_disable_device - disables idle PM for a CPU
	345	* @dev: the CPU
	346	*
	347	* This function must be called between cpuidle_pause_and_lock and
	348	* cpuidle_resume_and_unlock when used externally.
	349	*/
	350	void cpuidle_disable_device(struct cpuidle_device *dev)
	351	{
	352	if (!dev->enabled)
	353	return;
752138df	354	if (!cpuidle_get_driver() \|\| !cpuidle_curr_governor)
4f86d3a8 LB	355	return;
	356
	357	dev->enabled = 0;
	358
	359	if (cpuidle_curr_governor->disable)
46bcfad7	360	cpuidle_curr_governor->disable(cpuidle_get_driver(), dev);
4f86d3a8 LB	361
	362	cpuidle_remove_state_sysfs(dev);
	363	enabled_devices--;
	364	}
	365
	366	EXPORT_SYMBOL_GPL(cpuidle_disable_device);
	367
	368	/**
dcb84f33 VP	369	* __cpuidle_register_device - internal register function called before register
dcb84f33 VP	370	* and enable routines
4f86d3a8	371	* @dev: the cpu
dcb84f33 VP	372	*
dcb84f33 VP	373	* cpuidle_lock mutex must be held before this is called
4f86d3a8	374	*/
dcb84f33	375	static int __cpuidle_register_device(struct cpuidle_device *dev)
4f86d3a8 LB	376	{
4f86d3a8 LB	377	int ret;
8a25a2fd	378	struct device *cpu_dev = get_cpu_device((unsigned long)dev->cpu);
752138df	379	struct cpuidle_driver *cpuidle_driver = cpuidle_get_driver();
4f86d3a8	380
8a25a2fd	381	if (!dev)
4f86d3a8	382	return -EINVAL;
752138df	383	if (!try_module_get(cpuidle_driver->owner))
4f86d3a8 LB	384	return -EINVAL;
	385
	386	init_completion(&dev->kobj_unregister);
	387
4f86d3a8 LB	388	per_cpu(cpuidle_devices, dev->cpu) = dev;
4f86d3a8 LB	389	list_add(&dev->device_list, &cpuidle_detected_devices);
8a25a2fd	390	if ((ret = cpuidle_add_sysfs(cpu_dev))) {
752138df	391	module_put(cpuidle_driver->owner);
4f86d3a8 LB	392	return ret;
	393	}
	394
dcb84f33 VP	395	dev->registered = 1;
	396	return 0;
	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
	407	mutex_lock(&cpuidle_lock);
	408
	409	if ((ret = __cpuidle_register_device(dev))) {
	410	mutex_unlock(&cpuidle_lock);
	411	return ret;
	412	}
	413
4f86d3a8 LB	414	cpuidle_enable_device(dev);
	415	cpuidle_install_idle_handler();
	416
	417	mutex_unlock(&cpuidle_lock);
	418
	419	return 0;
	420
	421	}
	422
	423	EXPORT_SYMBOL_GPL(cpuidle_register_device);
	424
	425	/**
	426	* cpuidle_unregister_device - unregisters a CPU's idle PM feature
	427	* @dev: the cpu
	428	*/
	429	void cpuidle_unregister_device(struct cpuidle_device *dev)
	430	{
8a25a2fd	431	struct device *cpu_dev = get_cpu_device((unsigned long)dev->cpu);
752138df	432	struct cpuidle_driver *cpuidle_driver = cpuidle_get_driver();
4f86d3a8	433
dcb84f33 VP	434	if (dev->registered == 0)
	435	return;
	436
4f86d3a8 LB	437	cpuidle_pause_and_lock();
	438
	439	cpuidle_disable_device(dev);
	440
8a25a2fd	441	cpuidle_remove_sysfs(cpu_dev);
4f86d3a8 LB	442	list_del(&dev->device_list);
	443	wait_for_completion(&dev->kobj_unregister);
	444	per_cpu(cpuidle_devices, dev->cpu) = NULL;
	445
	446	cpuidle_resume_and_unlock();
	447
752138df	448	module_put(cpuidle_driver->owner);
4f86d3a8 LB	449	}
	450
	451	EXPORT_SYMBOL_GPL(cpuidle_unregister_device);
	452
	453	#ifdef CONFIG_SMP
	454
	455	static void smp_callback(void *v)
	456	{
	457	/* we already woke the CPU up, nothing more to do */
	458	}
	459
	460	/*
	461	* This function gets called when a part of the kernel has a new latency
	462	* requirement. This means we need to get all processors out of their C-state,
	463	* and then recalculate a new suitable C-state. Just do a cross-cpu IPI; that
	464	* wakes them all right up.
	465	*/
	466	static int cpuidle_latency_notify(struct notifier_block *b,
	467	unsigned long l, void *v)
	468	{
8691e5a8	469	smp_call_function(smp_callback, NULL, 1);
4f86d3a8 LB	470	return NOTIFY_OK;
	471	}
	472
	473	static struct notifier_block cpuidle_latency_notifier = {
	474	.notifier_call = cpuidle_latency_notify,
	475	};
	476
d82b3518 MG	477	static inline void latency_notifier_init(struct notifier_block *n)
	478	{
	479	pm_qos_add_notifier(PM_QOS_CPU_DMA_LATENCY, n);
	480	}
4f86d3a8 LB	481
	482	#else /* CONFIG_SMP */
	483
	484	#define latency_notifier_init(x) do { } while (0)
	485
	486	#endif /* CONFIG_SMP */
	487
	488	/**
	489	* cpuidle_init - core initializer
	490	*/
	491	static int __init cpuidle_init(void)
	492	{
	493	int ret;
	494
62027aea LB	495	if (cpuidle_disabled())
	496	return -ENODEV;
	497
8a25a2fd	498	ret = cpuidle_add_interface(cpu_subsys.dev_root);
4f86d3a8 LB	499	if (ret)
	500	return ret;
	501
	502	latency_notifier_init(&cpuidle_latency_notifier);
	503
	504	return 0;
	505	}
	506
62027aea	507	module_param(off, int, 0444);
4f86d3a8	508	core_initcall(cpuidle_init);