[GitHub/mt8127/android_kernel_alcatel_ttab.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_PER_CPU(struct cpuidle_device, cpuidle_dev);

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);

/**
 * cpuidle_unregister: unregister a driver and the devices. This function
 * can be used only if the driver has been previously registered through
 * the cpuidle_register function.
 *
 * @drv: a valid pointer to a struct cpuidle_driver
 */
void cpuidle_unregister(struct cpuidle_driver *drv)
{
	int cpu;
	struct cpuidle_device *device;

	for_each_possible_cpu(cpu) {
		device = &per_cpu(cpuidle_dev, cpu);
		cpuidle_unregister_device(device);
	}

	cpuidle_unregister_driver(drv);
}
EXPORT_SYMBOL_GPL(cpuidle_unregister);

/**
 * cpuidle_register: registers the driver and the cpu devices with the
 * coupled_cpus passed as parameter. This function is used for all common
 * initialization pattern there are in the arch specific drivers. The
 * devices is globally defined in this file.
 *
 * @drv         : a valid pointer to a struct cpuidle_driver
 * @coupled_cpus: a cpumask for the coupled states
 *
 * Returns 0 on success, < 0 otherwise
 */
int cpuidle_register(struct cpuidle_driver *drv,
		     const struct cpumask *const coupled_cpus)
{
	int ret, cpu;
	struct cpuidle_device *device;

	ret = cpuidle_register_driver(drv);
	if (ret) {
		pr_err("failed to register cpuidle driver\n");
		return ret;
	}

	for_each_possible_cpu(cpu) {
		device = &per_cpu(cpuidle_dev, cpu);
		device->cpu = cpu;

#ifdef CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED
		/*
		 * On multiplatform for ARM, the coupled idle states could
		 * enabled in the kernel even if the cpuidle driver does not
		 * use it. Note, coupled_cpus is a struct copy.
		 */
		if (coupled_cpus)
			device->coupled_cpus = *coupled_cpus;
#endif
		ret = cpuidle_register_device(device);
		if (!ret)
			continue;

		pr_err("Failed to register cpuidle device for cpu%d\n", cpu);

		cpuidle_unregister(drv);
		break;
	}

	return ret;
}
EXPORT_SYMBOL_GPL(cpuidle_register);

#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);
4c637b21	27	DEFINE_PER_CPU(struct cpuidle_device, cpuidle_dev);
4f86d3a8 LB	28
	29	DEFINE_MUTEX(cpuidle_lock);
	30	LIST_HEAD(cpuidle_detected_devices);
4f86d3a8 LB	31
4f86d3a8 LB	32	static int enabled_devices;
62027aea	33	static int off __read_mostly;
a0bfa137	34	static int initialized __read_mostly;
62027aea LB	35
	36	int cpuidle_disabled(void)
	37	{
	38	return off;
	39	}
d91ee586 LB	40	void disable_cpuidle(void)
	41	{
	42	off = 1;
	43	}
4f86d3a8	44
dcb84f33 VP	45	static int __cpuidle_register_device(struct cpuidle_device *dev);
dcb84f33 VP	46
1a022e3f BO	47	/**
	48	* cpuidle_play_dead - cpu off-lining
	49	*
ee01e663	50	* Returns in case of an error or no driver
1a022e3f BO	51	*/
	52	int cpuidle_play_dead(void)
	53	{
	54	struct cpuidle_device *dev = __this_cpu_read(cpuidle_devices);
bf4d1b5d	55	struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);
8aef33a7	56	int i;
1a022e3f	57
ee01e663 TK	58	if (!drv)
	59	return -ENODEV;
	60
1a022e3f	61	/* Find lowest-power state that supports long-term idle */
8aef33a7 DL	62	for (i = drv->state_count - 1; i >= CPUIDLE_DRIVER_STATE_START; i--)
	63	if (drv->states[i].enter_dead)
	64	return drv->states[i].enter_dead(dev, i);
1a022e3f BO	65
	66	return -ENODEV;
	67	}
	68
56cfbf74 CC	69	/**
	70	* cpuidle_enter_state - enter the state and update stats
	71	* @dev: cpuidle device for this cpu
	72	* @drv: cpuidle driver for this cpu
	73	* @next_state: index into drv->states of the state to enter
	74	*/
	75	int cpuidle_enter_state(struct cpuidle_device dev, struct cpuidle_driver drv,
554c06ba	76	int index)
56cfbf74 CC	77	{
	78	int entered_state;
	79
554c06ba DL	80	struct cpuidle_state *target_state = &drv->states[index];
	81	ktime_t time_start, time_end;
	82	s64 diff;
	83
	84	time_start = ktime_get();
	85
	86	entered_state = target_state->enter(dev, drv, index);
	87
	88	time_end = ktime_get();
	89
	90	local_irq_enable();
	91
	92	diff = ktime_to_us(ktime_sub(time_end, time_start));
	93	if (diff > INT_MAX)
	94	diff = INT_MAX;
	95
	96	dev->last_residency = (int) diff;
56cfbf74 CC	97
	98	if (entered_state >= 0) {
	99	/* Update cpuidle counters */
	100	/* This can be moved to within driver enter routine
	101	* but that results in multiple copies of same code.
	102	*/
a474a515	103	dev->states_usage[entered_state].time += dev->last_residency;
56cfbf74 CC	104	dev->states_usage[entered_state].usage++;
	105	} else {
	106	dev->last_residency = 0;
	107	}
	108
	109	return entered_state;
	110	}
	111
4f86d3a8 LB	112	/**
	113	* cpuidle_idle_call - the main idle loop
	114	*
	115	* NOTE: no locks or semaphores should be used here
a0bfa137	116	* return non-zero on failure
4f86d3a8	117	*/
a0bfa137	118	int cpuidle_idle_call(void)
4f86d3a8	119	{
4a6f4fe8	120	struct cpuidle_device *dev = __this_cpu_read(cpuidle_devices);
bf4d1b5d	121	struct cpuidle_driver *drv;
e978aa7d	122	int next_state, entered_state;
4f86d3a8	123
a0bfa137 LB	124	if (off)
	125	return -ENODEV;
	126
	127	if (!initialized)
	128	return -ENODEV;
	129
4f86d3a8	130	/* check if the device is ready */
a0bfa137 LB	131	if (!dev \|\| !dev->enabled)
a0bfa137 LB	132	return -EBUSY;
4f86d3a8	133
bf4d1b5d DL	134	drv = cpuidle_get_cpu_driver(dev);
bf4d1b5d DL	135
4f86d3a8	136	/* ask the governor for the next state */
46bcfad7	137	next_state = cpuidle_curr_governor->select(drv, dev);
246eb7f0	138	if (need_resched()) {
d73d68dc YS	139	dev->last_residency = 0;
	140	/* give the governor an opportunity to reflect on the outcome */
	141	if (cpuidle_curr_governor->reflect)
	142	cpuidle_curr_governor->reflect(dev, next_state);
246eb7f0	143	local_irq_enable();
a0bfa137	144	return 0;
246eb7f0 KH	145	}
246eb7f0 KH	146
76027ea8	147	trace_cpu_idle_rcuidle(next_state, dev->cpu);
f77cfe4e	148
b60e6a0e DL	149	if (drv->states[next_state].flags & CPUIDLE_FLAG_TIMER_STOP)
	150	clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER,
	151	&dev->cpu);
	152
4126c019 CC	153	if (cpuidle_state_is_coupled(dev, drv, next_state))
	154	entered_state = cpuidle_enter_state_coupled(dev, drv,
	155	next_state);
	156	else
	157	entered_state = cpuidle_enter_state(dev, drv, next_state);
f77cfe4e	158
b60e6a0e DL	159	if (drv->states[next_state].flags & CPUIDLE_FLAG_TIMER_STOP)
	160	clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_EXIT,
	161	&dev->cpu);
	162
76027ea8	163	trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, dev->cpu);
f77cfe4e	164
4f86d3a8 LB	165	/* give the governor an opportunity to reflect on the outcome */
4f86d3a8 LB	166	if (cpuidle_curr_governor->reflect)
e978aa7d	167	cpuidle_curr_governor->reflect(dev, entered_state);
a0bfa137 LB	168
a0bfa137 LB	169	return 0;
4f86d3a8 LB	170	}
	171
	172	/**
	173	* cpuidle_install_idle_handler - installs the cpuidle idle loop handler
	174	*/
	175	void cpuidle_install_idle_handler(void)
	176	{
a0bfa137	177	if (enabled_devices) {
4f86d3a8 LB	178	/* Make sure all changes finished before we switch to new idle */
4f86d3a8 LB	179	smp_wmb();
a0bfa137	180	initialized = 1;
4f86d3a8 LB	181	}
	182	}
	183
	184	/**
	185	* cpuidle_uninstall_idle_handler - uninstalls the cpuidle idle loop handler
	186	*/
	187	void cpuidle_uninstall_idle_handler(void)
	188	{
a0bfa137 LB	189	if (enabled_devices) {
a0bfa137 LB	190	initialized = 0;
4a162513	191	kick_all_cpus_sync();
4f86d3a8 LB	192	}
	193	}
	194
	195	/**
	196	* cpuidle_pause_and_lock - temporarily disables CPUIDLE
	197	*/
	198	void cpuidle_pause_and_lock(void)
	199	{
	200	mutex_lock(&cpuidle_lock);
	201	cpuidle_uninstall_idle_handler();
	202	}
	203
	204	EXPORT_SYMBOL_GPL(cpuidle_pause_and_lock);
	205
	206	/**
	207	* cpuidle_resume_and_unlock - resumes CPUIDLE operation
	208	*/
	209	void cpuidle_resume_and_unlock(void)
	210	{
	211	cpuidle_install_idle_handler();
	212	mutex_unlock(&cpuidle_lock);
	213	}
	214
	215	EXPORT_SYMBOL_GPL(cpuidle_resume_and_unlock);
	216
8651f97b PM	217	/* Currently used in suspend/resume path to suspend cpuidle */
	218	void cpuidle_pause(void)
	219	{
	220	mutex_lock(&cpuidle_lock);
	221	cpuidle_uninstall_idle_handler();
	222	mutex_unlock(&cpuidle_lock);
	223	}
	224
	225	/* Currently used in suspend/resume path to resume cpuidle */
	226	void cpuidle_resume(void)
	227	{
	228	mutex_lock(&cpuidle_lock);
	229	cpuidle_install_idle_handler();
	230	mutex_unlock(&cpuidle_lock);
	231	}
	232
d8c216cf	233	#ifdef CONFIG_ARCH_HAS_CPU_RELAX
46bcfad7 DD	234	static int poll_idle(struct cpuidle_device *dev,
46bcfad7 DD	235	struct cpuidle_driver *drv, int index)
d8c216cf RW	236	{
	237	ktime_t t1, t2;
	238	s64 diff;
d8c216cf RW	239
	240	t1 = ktime_get();
	241	local_irq_enable();
	242	while (!need_resched())
	243	cpu_relax();
	244
	245	t2 = ktime_get();
	246	diff = ktime_to_us(ktime_sub(t2, t1));
	247	if (diff > INT_MAX)
	248	diff = INT_MAX;
	249
e978aa7d DD	250	dev->last_residency = (int) diff;
	251
	252	return index;
d8c216cf RW	253	}
d8c216cf RW	254
46bcfad7	255	static void poll_idle_init(struct cpuidle_driver *drv)
d8c216cf	256	{
46bcfad7	257	struct cpuidle_state *state = &drv->states[0];
d8c216cf	258
720f1c30	259	snprintf(state->name, CPUIDLE_NAME_LEN, "POLL");
d8c216cf RW	260	snprintf(state->desc, CPUIDLE_DESC_LEN, "CPUIDLE CORE POLL IDLE");
	261	state->exit_latency = 0;
	262	state->target_residency = 0;
	263	state->power_usage = -1;
d247632c	264	state->flags = 0;
d8c216cf	265	state->enter = poll_idle;
cbc9ef02	266	state->disabled = false;
d8c216cf RW	267	}
d8c216cf RW	268	#else
46bcfad7	269	static void poll_idle_init(struct cpuidle_driver *drv) {}
d8c216cf RW	270	#endif /* CONFIG_ARCH_HAS_CPU_RELAX */
d8c216cf RW	271
4f86d3a8 LB	272	/**
	273	* cpuidle_enable_device - enables idle PM for a CPU
	274	* @dev: the CPU
	275	*
	276	* This function must be called between cpuidle_pause_and_lock and
	277	* cpuidle_resume_and_unlock when used externally.
	278	*/
	279	int cpuidle_enable_device(struct cpuidle_device *dev)
	280	{
	281	int ret, i;
bf4d1b5d	282	struct cpuidle_driver *drv;
4f86d3a8	283
1b0a0e9a SB	284	if (!dev)
	285	return -EINVAL;
	286
4f86d3a8 LB	287	if (dev->enabled)
4f86d3a8 LB	288	return 0;
bf4d1b5d DL	289
	290	drv = cpuidle_get_cpu_driver(dev);
	291
e1689795	292	if (!drv \|\| !cpuidle_curr_governor)
4f86d3a8	293	return -EIO;
bf4d1b5d	294
4f86d3a8	295	if (!dev->state_count)
fc850f39	296	dev->state_count = drv->state_count;
4f86d3a8	297
dcb84f33 VP	298	if (dev->registered == 0) {
	299	ret = __cpuidle_register_device(dev);
	300	if (ret)
	301	return ret;
	302	}
	303
e1689795	304	poll_idle_init(drv);
d8c216cf	305
bf4d1b5d DL	306	ret = cpuidle_add_device_sysfs(dev);
bf4d1b5d DL	307	if (ret)
4f86d3a8 LB	308	return ret;
	309
	310	if (cpuidle_curr_governor->enable &&
e1689795	311	(ret = cpuidle_curr_governor->enable(drv, dev)))
4f86d3a8 LB	312	goto fail_sysfs;
	313
	314	for (i = 0; i < dev->state_count; i++) {
4202735e DD	315	dev->states_usage[i].usage = 0;
4202735e DD	316	dev->states_usage[i].time = 0;
4f86d3a8 LB	317	}
4f86d3a8 LB	318	dev->last_residency = 0;
4f86d3a8 LB	319
	320	smp_wmb();
	321
	322	dev->enabled = 1;
	323
	324	enabled_devices++;
	325	return 0;
	326
	327	fail_sysfs:
bf4d1b5d	328	cpuidle_remove_device_sysfs(dev);
4f86d3a8 LB	329
	330	return ret;
	331	}
	332
	333	EXPORT_SYMBOL_GPL(cpuidle_enable_device);
	334
	335	/**
	336	* cpuidle_disable_device - disables idle PM for a CPU
	337	* @dev: the CPU
	338	*
	339	* This function must be called between cpuidle_pause_and_lock and
	340	* cpuidle_resume_and_unlock when used externally.
	341	*/
	342	void cpuidle_disable_device(struct cpuidle_device *dev)
	343	{
bf4d1b5d DL	344	struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);
bf4d1b5d DL	345
cf31cd1a	346	if (!dev \|\| !dev->enabled)
4f86d3a8	347	return;
bf4d1b5d DL	348
bf4d1b5d DL	349	if (!drv \|\| !cpuidle_curr_governor)
4f86d3a8 LB	350	return;
	351
	352	dev->enabled = 0;
	353
	354	if (cpuidle_curr_governor->disable)
bf4d1b5d	355	cpuidle_curr_governor->disable(drv, dev);
4f86d3a8	356
bf4d1b5d	357	cpuidle_remove_device_sysfs(dev);
4f86d3a8 LB	358	enabled_devices--;
	359	}
	360
	361	EXPORT_SYMBOL_GPL(cpuidle_disable_device);
	362
	363	/**
dcb84f33 VP	364	* __cpuidle_register_device - internal register function called before register
dcb84f33 VP	365	* and enable routines
4f86d3a8	366	* @dev: the cpu
dcb84f33 VP	367	*
dcb84f33 VP	368	* cpuidle_lock mutex must be held before this is called
4f86d3a8	369	*/
dcb84f33	370	static int __cpuidle_register_device(struct cpuidle_device *dev)
4f86d3a8 LB	371	{
4f86d3a8 LB	372	int ret;
bf4d1b5d	373	struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);
4f86d3a8	374
bf4d1b5d	375	if (!try_module_get(drv->owner))
4f86d3a8 LB	376	return -EINVAL;
4f86d3a8 LB	377
4f86d3a8 LB	378	per_cpu(cpuidle_devices, dev->cpu) = dev;
4f86d3a8 LB	379	list_add(&dev->device_list, &cpuidle_detected_devices);
1aef40e2	380	ret = cpuidle_add_sysfs(dev);
3af272ab CC	381	if (ret)
3af272ab CC	382	goto err_sysfs;
4f86d3a8	383
4126c019 CC	384	ret = cpuidle_coupled_register_device(dev);
	385	if (ret)
	386	goto err_coupled;
4f86d3a8	387
dcb84f33 VP	388	dev->registered = 1;
dcb84f33 VP	389	return 0;
3af272ab	390
4126c019	391	err_coupled:
1aef40e2	392	cpuidle_remove_sysfs(dev);
3af272ab CC	393	err_sysfs:
	394	list_del(&dev->device_list);
	395	per_cpu(cpuidle_devices, dev->cpu) = NULL;
bf4d1b5d	396	module_put(drv->owner);
3af272ab	397	return ret;
dcb84f33 VP	398	}
	399
	400	/**
	401	* cpuidle_register_device - registers a CPU's idle PM feature
	402	* @dev: the cpu
	403	*/
	404	int cpuidle_register_device(struct cpuidle_device *dev)
	405	{
	406	int ret;
	407
1b0a0e9a SB	408	if (!dev)
	409	return -EINVAL;
	410
dcb84f33 VP	411	mutex_lock(&cpuidle_lock);
	412
	413	if ((ret = __cpuidle_register_device(dev))) {
	414	mutex_unlock(&cpuidle_lock);
	415	return ret;
	416	}
	417
4f86d3a8 LB	418	cpuidle_enable_device(dev);
	419	cpuidle_install_idle_handler();
	420
	421	mutex_unlock(&cpuidle_lock);
	422
	423	return 0;
	424
	425	}
	426
	427	EXPORT_SYMBOL_GPL(cpuidle_register_device);
	428
	429	/**
	430	* cpuidle_unregister_device - unregisters a CPU's idle PM feature
	431	* @dev: the cpu
	432	*/
	433	void cpuidle_unregister_device(struct cpuidle_device *dev)
	434	{
bf4d1b5d	435	struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);
4f86d3a8	436
dcb84f33 VP	437	if (dev->registered == 0)
	438	return;
	439
4f86d3a8 LB	440	cpuidle_pause_and_lock();
	441
	442	cpuidle_disable_device(dev);
	443
1aef40e2	444	cpuidle_remove_sysfs(dev);
4f86d3a8	445	list_del(&dev->device_list);
4f86d3a8 LB	446	per_cpu(cpuidle_devices, dev->cpu) = NULL;
4f86d3a8 LB	447
4126c019 CC	448	cpuidle_coupled_unregister_device(dev);
4126c019 CC	449
4f86d3a8 LB	450	cpuidle_resume_and_unlock();
4f86d3a8 LB	451
bf4d1b5d	452	module_put(drv->owner);
4f86d3a8 LB	453	}
	454
	455	EXPORT_SYMBOL_GPL(cpuidle_unregister_device);
	456
1c192d04	457	/**
4c637b21 DL	458	* cpuidle_unregister: unregister a driver and the devices. This function
	459	* can be used only if the driver has been previously registered through
	460	* the cpuidle_register function.
	461	*
	462	* @drv: a valid pointer to a struct cpuidle_driver
	463	*/
	464	void cpuidle_unregister(struct cpuidle_driver *drv)
	465	{
	466	int cpu;
	467	struct cpuidle_device *device;
	468
	469	for_each_possible_cpu(cpu) {
	470	device = &per_cpu(cpuidle_dev, cpu);
	471	cpuidle_unregister_device(device);
	472	}
	473
	474	cpuidle_unregister_driver(drv);
	475	}
	476	EXPORT_SYMBOL_GPL(cpuidle_unregister);
	477
	478	/**
	479	* cpuidle_register: registers the driver and the cpu devices with the
	480	* coupled_cpus passed as parameter. This function is used for all common
	481	* initialization pattern there are in the arch specific drivers. The
	482	* devices is globally defined in this file.
	483	*
	484	* @drv : a valid pointer to a struct cpuidle_driver
	485	* @coupled_cpus: a cpumask for the coupled states
	486	*
	487	* Returns 0 on success, < 0 otherwise
	488	*/
	489	int cpuidle_register(struct cpuidle_driver *drv,
	490	const struct cpumask *const coupled_cpus)
	491	{
	492	int ret, cpu;
	493	struct cpuidle_device *device;
	494
	495	ret = cpuidle_register_driver(drv);
	496	if (ret) {
	497	pr_err("failed to register cpuidle driver\n");
	498	return ret;
	499	}
	500
	501	for_each_possible_cpu(cpu) {
	502	device = &per_cpu(cpuidle_dev, cpu);
	503	device->cpu = cpu;
	504
	505	#ifdef CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED
	506	/*
	507	* On multiplatform for ARM, the coupled idle states could
	508	* enabled in the kernel even if the cpuidle driver does not
	509	* use it. Note, coupled_cpus is a struct copy.
	510	*/
	511	if (coupled_cpus)
	512	device->coupled_cpus = *coupled_cpus;
	513	#endif
	514	ret = cpuidle_register_device(device);
	515	if (!ret)
	516	continue;
	517
	518	pr_err("Failed to register cpuidle device for cpu%d\n", cpu);
	519
	520	cpuidle_unregister(drv);
	521	break;
522	}
523
524	return ret;
525	}
526	EXPORT_SYMBOL_GPL(cpuidle_register);
527
4f86d3a8 LB	528	#ifdef CONFIG_SMP
	529
	530	static void smp_callback(void *v)
	531	{
	532	/* we already woke the CPU up, nothing more to do */
	533	}
	534
	535	/*
	536	* This function gets called when a part of the kernel has a new latency
	537	* requirement. This means we need to get all processors out of their C-state,
	538	* and then recalculate a new suitable C-state. Just do a cross-cpu IPI; that
	539	* wakes them all right up.
	540	*/
	541	static int cpuidle_latency_notify(struct notifier_block *b,
	542	unsigned long l, void *v)
	543	{
8691e5a8	544	smp_call_function(smp_callback, NULL, 1);
4f86d3a8 LB	545	return NOTIFY_OK;
	546	}
	547
	548	static struct notifier_block cpuidle_latency_notifier = {
	549	.notifier_call = cpuidle_latency_notify,
	550	};
	551
d82b3518 MG	552	static inline void latency_notifier_init(struct notifier_block *n)
	553	{
	554	pm_qos_add_notifier(PM_QOS_CPU_DMA_LATENCY, n);
	555	}
4f86d3a8 LB	556
	557	#else /* CONFIG_SMP */
	558
	559	#define latency_notifier_init(x) do { } while (0)
	560
	561	#endif /* CONFIG_SMP */
	562
	563	/**
	564	* cpuidle_init - core initializer
	565	*/
	566	static int __init cpuidle_init(void)
	567	{
	568	int ret;
	569
62027aea LB	570	if (cpuidle_disabled())
	571	return -ENODEV;
	572
8a25a2fd	573	ret = cpuidle_add_interface(cpu_subsys.dev_root);
4f86d3a8 LB	574	if (ret)
	575	return ret;
	576
	577	latency_notifier_init(&cpuidle_latency_notifier);
	578
	579	return 0;
	580	}
	581
62027aea	582	module_param(off, int, 0444);
4f86d3a8	583	core_initcall(cpuidle_init);