[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/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;
}

/**
 * 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;
	bool broadcast;

	if (off || !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;
	}

	broadcast = !!(drv->states[next_state].flags & CPUIDLE_FLAG_TIMER_STOP);

	if (broadcast &&
	    clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER, &dev->cpu))
		return -EBUSY;


	trace_cpu_idle_rcuidle(next_state, dev->cpu);

	if (cpuidle_state_is_coupled(dev, drv, next_state))
		entered_state = cpuidle_enter_state_coupled(dev, drv,
							    next_state);
	else
		entered_state = cpuidle_enter_state(dev, drv, next_state);

	trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, dev->cpu);

	if (broadcast)
		clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_EXIT, &dev->cpu);

	/* give the governor an opportunity to reflect on the outcome */
	if (cpuidle_curr_governor->reflect)
		cpuidle_curr_governor->reflect(dev, entered_state);

	return 0;
}

/**
 * cpuidle_install_idle_handler - installs the cpuidle idle loop handler
 */
void cpuidle_install_idle_handler(void)
{
	if (enabled_devices) {
		/* Make sure all changes finished before we switch to new idle */
		smp_wmb();
		initialized = 1;
	}
}

/**
 * cpuidle_uninstall_idle_handler - uninstalls the cpuidle idle loop handler
 */
void cpuidle_uninstall_idle_handler(void)
{
	if (enabled_devices) {
		initialized = 0;
		kick_all_cpus_sync();
	}
}

/**
 * cpuidle_pause_and_lock - temporarily disables CPUIDLE
 */
void cpuidle_pause_and_lock(void)
{
	mutex_lock(&cpuidle_lock);
	cpuidle_uninstall_idle_handler();
}

EXPORT_SYMBOL_GPL(cpuidle_pause_and_lock);

/**
 * cpuidle_resume_and_unlock - resumes CPUIDLE operation
 */
void cpuidle_resume_and_unlock(void)
{
	cpuidle_install_idle_handler();
	mutex_unlock(&cpuidle_lock);
}

EXPORT_SYMBOL_GPL(cpuidle_resume_and_unlock);

/* Currently used in suspend/resume path to suspend cpuidle */
void cpuidle_pause(void)
{
	mutex_lock(&cpuidle_lock);
	cpuidle_uninstall_idle_handler();
	mutex_unlock(&cpuidle_lock);
}

/* Currently used in suspend/resume path to resume cpuidle */
void cpuidle_resume(void)
{
	mutex_lock(&cpuidle_lock);
	cpuidle_install_idle_handler();
	mutex_unlock(&cpuidle_lock);
}

/**
 * cpuidle_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;
	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->registered)
		return -EINVAL;

	if (!dev->state_count)
		dev->state_count = drv->state_count;

	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;

	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);

static void __cpuidle_unregister_device(struct cpuidle_device *dev)
{
	struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);

	list_del(&dev->device_list);
	per_cpu(cpuidle_devices, dev->cpu) = NULL;
	module_put(drv->owner);
}

static void __cpuidle_device_init(struct cpuidle_device *dev)
{
	memset(dev->states_usage, 0, sizeof(dev->states_usage));
	dev->last_residency = 0;
}

/**
 * __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_coupled_register_device(dev);
	if (ret)
		__cpuidle_unregister_device(dev);
	else
		dev->registered = 1;

	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 = -EBUSY;

	if (!dev)
		return -EINVAL;

	mutex_lock(&cpuidle_lock);

	if (dev->registered)
		goto out_unlock;

	__cpuidle_device_init(dev);

	ret = __cpuidle_register_device(dev);
	if (ret)
		goto out_unlock;

	ret = cpuidle_add_sysfs(dev);
	if (ret)
		goto out_unregister;

	ret = cpuidle_enable_device(dev);
	if (ret)
		goto out_sysfs;

	cpuidle_install_idle_handler();

out_unlock:
	mutex_unlock(&cpuidle_lock);

	return ret;

out_sysfs:
	cpuidle_remove_sysfs(dev);
out_unregister:
	__cpuidle_unregister_device(dev);
	goto out_unlock;
}

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)
{
	if (!dev || dev->registered == 0)
		return;

	cpuidle_pause_and_lock();

	cpuidle_disable_device(dev);

	cpuidle_remove_sysfs(dev);

	__cpuidle_unregister_device(dev);

	cpuidle_coupled_unregister_device(dev);

	cpuidle_resume_and_unlock();
}

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_cpu(cpu, drv->cpumask) {
		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_cpu(cpu, drv->cpumask) {
		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 be
		 * 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
1a022e3f BO	45	/**
	46	* cpuidle_play_dead - cpu off-lining
	47	*
ee01e663	48	* Returns in case of an error or no driver
1a022e3f BO	49	*/
	50	int cpuidle_play_dead(void)
	51	{
	52	struct cpuidle_device *dev = __this_cpu_read(cpuidle_devices);
bf4d1b5d	53	struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);
8aef33a7	54	int i;
1a022e3f	55
ee01e663 TK	56	if (!drv)
	57	return -ENODEV;
	58
1a022e3f	59	/* Find lowest-power state that supports long-term idle */
8aef33a7 DL	60	for (i = drv->state_count - 1; i >= CPUIDLE_DRIVER_STATE_START; i--)
	61	if (drv->states[i].enter_dead)
	62	return drv->states[i].enter_dead(dev, i);
1a022e3f BO	63
	64	return -ENODEV;
	65	}
	66
56cfbf74 CC	67	/**
	68	* cpuidle_enter_state - enter the state and update stats
	69	* @dev: cpuidle device for this cpu
	70	* @drv: cpuidle driver for this cpu
	71	* @next_state: index into drv->states of the state to enter
	72	*/
	73	int cpuidle_enter_state(struct cpuidle_device dev, struct cpuidle_driver drv,
554c06ba	74	int index)
56cfbf74 CC	75	{
	76	int entered_state;
	77
554c06ba DL	78	struct cpuidle_state *target_state = &drv->states[index];
	79	ktime_t time_start, time_end;
	80	s64 diff;
	81
	82	time_start = ktime_get();
	83
	84	entered_state = target_state->enter(dev, drv, index);
	85
	86	time_end = ktime_get();
	87
	88	local_irq_enable();
	89
	90	diff = ktime_to_us(ktime_sub(time_end, time_start));
	91	if (diff > INT_MAX)
	92	diff = INT_MAX;
	93
	94	dev->last_residency = (int) diff;
56cfbf74 CC	95
	96	if (entered_state >= 0) {
	97	/* Update cpuidle counters */
	98	/* This can be moved to within driver enter routine
	99	* but that results in multiple copies of same code.
	100	*/
a474a515	101	dev->states_usage[entered_state].time += dev->last_residency;
56cfbf74 CC	102	dev->states_usage[entered_state].usage++;
	103	} else {
	104	dev->last_residency = 0;
	105	}
	106
	107	return entered_state;
	108	}
	109
4f86d3a8 LB	110	/**
	111	* cpuidle_idle_call - the main idle loop
	112	*
	113	* NOTE: no locks or semaphores should be used here
a0bfa137	114	* return non-zero on failure
4f86d3a8	115	*/
a0bfa137	116	int cpuidle_idle_call(void)
4f86d3a8	117	{
4a6f4fe8	118	struct cpuidle_device *dev = __this_cpu_read(cpuidle_devices);
bf4d1b5d	119	struct cpuidle_driver *drv;
e978aa7d	120	int next_state, entered_state;
fb11c9c6	121	bool broadcast;
4f86d3a8	122
9b29a86f	123	if (off \|\| !initialized)
a0bfa137 LB	124	return -ENODEV;
a0bfa137 LB	125
4f86d3a8	126	/* check if the device is ready */
a0bfa137 LB	127	if (!dev \|\| !dev->enabled)
a0bfa137 LB	128	return -EBUSY;
4f86d3a8	129
bf4d1b5d DL	130	drv = cpuidle_get_cpu_driver(dev);
bf4d1b5d DL	131
4f86d3a8	132	/* ask the governor for the next state */
46bcfad7	133	next_state = cpuidle_curr_governor->select(drv, dev);
246eb7f0	134	if (need_resched()) {
d73d68dc YS	135	dev->last_residency = 0;
	136	/* give the governor an opportunity to reflect on the outcome */
	137	if (cpuidle_curr_governor->reflect)
	138	cpuidle_curr_governor->reflect(dev, next_state);
246eb7f0	139	local_irq_enable();
a0bfa137	140	return 0;
246eb7f0 KH	141	}
246eb7f0 KH	142
fb11c9c6 VK	143	broadcast = !!(drv->states[next_state].flags & CPUIDLE_FLAG_TIMER_STOP);
fb11c9c6 VK	144
ba8f20c2 PM	145	if (broadcast &&
	146	clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER, &dev->cpu))
	147	return -EBUSY;
	148
	149
	150	trace_cpu_idle_rcuidle(next_state, dev->cpu);
b60e6a0e	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
ba8f20c2 PM	158	trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, dev->cpu);
ba8f20c2 PM	159
fb11c9c6	160	if (broadcast)
6d281e97	161	clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_EXIT, &dev->cpu);
b60e6a0e	162
4f86d3a8 LB	163	/* give the governor an opportunity to reflect on the outcome */
4f86d3a8 LB	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;
4a162513	189	kick_all_cpus_sync();
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
8651f97b PM	215	/* Currently used in suspend/resume path to suspend cpuidle */
	216	void cpuidle_pause(void)
	217	{
	218	mutex_lock(&cpuidle_lock);
	219	cpuidle_uninstall_idle_handler();
	220	mutex_unlock(&cpuidle_lock);
	221	}
	222
	223	/* Currently used in suspend/resume path to resume cpuidle */
	224	void cpuidle_resume(void)
	225	{
	226	mutex_lock(&cpuidle_lock);
	227	cpuidle_install_idle_handler();
	228	mutex_unlock(&cpuidle_lock);
	229	}
	230
4f86d3a8 LB	231	/**
	232	* cpuidle_enable_device - enables idle PM for a CPU
	233	* @dev: the CPU
	234	*
	235	* This function must be called between cpuidle_pause_and_lock and
	236	* cpuidle_resume_and_unlock when used externally.
	237	*/
	238	int cpuidle_enable_device(struct cpuidle_device *dev)
	239	{
5df0aa73	240	int ret;
bf4d1b5d	241	struct cpuidle_driver *drv;
4f86d3a8	242
1b0a0e9a SB	243	if (!dev)
	244	return -EINVAL;
	245
4f86d3a8 LB	246	if (dev->enabled)
4f86d3a8 LB	247	return 0;
bf4d1b5d DL	248
	249	drv = cpuidle_get_cpu_driver(dev);
	250
e1689795	251	if (!drv \|\| !cpuidle_curr_governor)
4f86d3a8	252	return -EIO;
bf4d1b5d	253
10b9d3f8 DL	254	if (!dev->registered)
	255	return -EINVAL;
	256
4f86d3a8	257	if (!dev->state_count)
fc850f39	258	dev->state_count = drv->state_count;
4f86d3a8	259
bf4d1b5d DL	260	ret = cpuidle_add_device_sysfs(dev);
bf4d1b5d DL	261	if (ret)
4f86d3a8 LB	262	return ret;
	263
	264	if (cpuidle_curr_governor->enable &&
e1689795	265	(ret = cpuidle_curr_governor->enable(drv, dev)))
4f86d3a8 LB	266	goto fail_sysfs;
4f86d3a8 LB	267
4f86d3a8 LB	268	smp_wmb();
	269
	270	dev->enabled = 1;
	271
	272	enabled_devices++;
	273	return 0;
	274
	275	fail_sysfs:
bf4d1b5d	276	cpuidle_remove_device_sysfs(dev);
4f86d3a8 LB	277
	278	return ret;
	279	}
	280
	281	EXPORT_SYMBOL_GPL(cpuidle_enable_device);
	282
	283	/**
	284	* cpuidle_disable_device - disables idle PM for a CPU
	285	* @dev: the CPU
	286	*
	287	* This function must be called between cpuidle_pause_and_lock and
	288	* cpuidle_resume_and_unlock when used externally.
	289	*/
	290	void cpuidle_disable_device(struct cpuidle_device *dev)
	291	{
bf4d1b5d DL	292	struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);
bf4d1b5d DL	293
cf31cd1a	294	if (!dev \|\| !dev->enabled)
4f86d3a8	295	return;
bf4d1b5d DL	296
bf4d1b5d DL	297	if (!drv \|\| !cpuidle_curr_governor)
4f86d3a8 LB	298	return;
	299
	300	dev->enabled = 0;
	301
	302	if (cpuidle_curr_governor->disable)
bf4d1b5d	303	cpuidle_curr_governor->disable(drv, dev);
4f86d3a8	304
bf4d1b5d	305	cpuidle_remove_device_sysfs(dev);
4f86d3a8 LB	306	enabled_devices--;
	307	}
	308
	309	EXPORT_SYMBOL_GPL(cpuidle_disable_device);
	310
f6bb51a5 DL	311	static void __cpuidle_unregister_device(struct cpuidle_device *dev)
	312	{
	313	struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);
	314
	315	list_del(&dev->device_list);
	316	per_cpu(cpuidle_devices, dev->cpu) = NULL;
	317	module_put(drv->owner);
	318	}
	319
267d4bf8	320	static void __cpuidle_device_init(struct cpuidle_device *dev)
5df0aa73 DL	321	{
	322	memset(dev->states_usage, 0, sizeof(dev->states_usage));
	323	dev->last_residency = 0;
5df0aa73 DL	324	}
5df0aa73 DL	325
4f86d3a8	326	/**
dcb84f33 VP	327	* __cpuidle_register_device - internal register function called before register
dcb84f33 VP	328	* and enable routines
4f86d3a8	329	* @dev: the cpu
dcb84f33 VP	330	*
dcb84f33 VP	331	* cpuidle_lock mutex must be held before this is called
4f86d3a8	332	*/
dcb84f33	333	static int __cpuidle_register_device(struct cpuidle_device *dev)
4f86d3a8 LB	334	{
4f86d3a8 LB	335	int ret;
bf4d1b5d	336	struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);
4f86d3a8	337
bf4d1b5d	338	if (!try_module_get(drv->owner))
4f86d3a8 LB	339	return -EINVAL;
4f86d3a8 LB	340
4f86d3a8 LB	341	per_cpu(cpuidle_devices, dev->cpu) = dev;
4f86d3a8 LB	342	list_add(&dev->device_list, &cpuidle_detected_devices);
4f86d3a8	343
4126c019	344	ret = cpuidle_coupled_register_device(dev);
47182668	345	if (ret)
f6bb51a5	346	__cpuidle_unregister_device(dev);
47182668 VK	347	else
47182668 VK	348	dev->registered = 1;
4f86d3a8	349
47182668	350	return ret;
dcb84f33 VP	351	}
	352
	353	/**
	354	* cpuidle_register_device - registers a CPU's idle PM feature
	355	* @dev: the cpu
	356	*/
	357	int cpuidle_register_device(struct cpuidle_device *dev)
	358	{
c878a52d	359	int ret = -EBUSY;
dcb84f33	360
1b0a0e9a SB	361	if (!dev)
	362	return -EINVAL;
	363
dcb84f33 VP	364	mutex_lock(&cpuidle_lock);
dcb84f33 VP	365
c878a52d DL	366	if (dev->registered)
	367	goto out_unlock;
	368
267d4bf8	369	__cpuidle_device_init(dev);
5df0aa73	370
f6bb51a5 DL	371	ret = __cpuidle_register_device(dev);
	372	if (ret)
	373	goto out_unlock;
	374
	375	ret = cpuidle_add_sysfs(dev);
	376	if (ret)
	377	goto out_unregister;
dcb84f33	378
10b9d3f8	379	ret = cpuidle_enable_device(dev);
f6bb51a5 DL	380	if (ret)
f6bb51a5 DL	381	goto out_sysfs;
10b9d3f8	382
4f86d3a8 LB	383	cpuidle_install_idle_handler();
4f86d3a8 LB	384
f6bb51a5	385	out_unlock:
4f86d3a8 LB	386	mutex_unlock(&cpuidle_lock);
4f86d3a8 LB	387
f6bb51a5 DL	388	return ret;
	389
	390	out_sysfs:
	391	cpuidle_remove_sysfs(dev);
	392	out_unregister:
	393	__cpuidle_unregister_device(dev);
	394	goto out_unlock;
4f86d3a8 LB	395	}
	396
	397	EXPORT_SYMBOL_GPL(cpuidle_register_device);
	398
	399	/**
	400	* cpuidle_unregister_device - unregisters a CPU's idle PM feature
	401	* @dev: the cpu
	402	*/
	403	void cpuidle_unregister_device(struct cpuidle_device *dev)
	404	{
813e8e3d	405	if (!dev \|\| dev->registered == 0)
dcb84f33 VP	406	return;
dcb84f33 VP	407
4f86d3a8 LB	408	cpuidle_pause_and_lock();
	409
	410	cpuidle_disable_device(dev);
	411
1aef40e2	412	cpuidle_remove_sysfs(dev);
f6bb51a5 DL	413
f6bb51a5 DL	414	__cpuidle_unregister_device(dev);
4f86d3a8	415
4126c019 CC	416	cpuidle_coupled_unregister_device(dev);
4126c019 CC	417
4f86d3a8	418	cpuidle_resume_and_unlock();
4f86d3a8 LB	419	}
	420
	421	EXPORT_SYMBOL_GPL(cpuidle_unregister_device);
	422
1c192d04	423	/**
4c637b21 DL	424	* cpuidle_unregister: unregister a driver and the devices. This function
	425	* can be used only if the driver has been previously registered through
	426	* the cpuidle_register function.
	427	*
	428	* @drv: a valid pointer to a struct cpuidle_driver
	429	*/
	430	void cpuidle_unregister(struct cpuidle_driver *drv)
	431	{
	432	int cpu;
	433	struct cpuidle_device *device;
	434
82467a5a	435	for_each_cpu(cpu, drv->cpumask) {
4c637b21 DL	436	device = &per_cpu(cpuidle_dev, cpu);
	437	cpuidle_unregister_device(device);
	438	}
	439
	440	cpuidle_unregister_driver(drv);
	441	}
	442	EXPORT_SYMBOL_GPL(cpuidle_unregister);
	443
	444	/**
	445	* cpuidle_register: registers the driver and the cpu devices with the
	446	* coupled_cpus passed as parameter. This function is used for all common
	447	* initialization pattern there are in the arch specific drivers. The
	448	* devices is globally defined in this file.
	449	*
	450	* @drv : a valid pointer to a struct cpuidle_driver
	451	* @coupled_cpus: a cpumask for the coupled states
	452	*
	453	* Returns 0 on success, < 0 otherwise
	454	*/
	455	int cpuidle_register(struct cpuidle_driver *drv,
	456	const struct cpumask *const coupled_cpus)
	457	{
	458	int ret, cpu;
	459	struct cpuidle_device *device;
	460
	461	ret = cpuidle_register_driver(drv);
	462	if (ret) {
	463	pr_err("failed to register cpuidle driver\n");
	464	return ret;
	465	}
	466
82467a5a	467	for_each_cpu(cpu, drv->cpumask) {
4c637b21 DL	468	device = &per_cpu(cpuidle_dev, cpu);
	469	device->cpu = cpu;
	470
	471	#ifdef CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED
	472	/*
caf4a36e	473	* On multiplatform for ARM, the coupled idle states could be
4c637b21 DL	474	* enabled in the kernel even if the cpuidle driver does not
	475	* use it. Note, coupled_cpus is a struct copy.
	476	*/
	477	if (coupled_cpus)
	478	device->coupled_cpus = *coupled_cpus;
	479	#endif
	480	ret = cpuidle_register_device(device);
	481	if (!ret)
	482	continue;
	483
	484	pr_err("Failed to register cpuidle device for cpu%d\n", cpu);
	485
	486	cpuidle_unregister(drv);
	487	break;
	488	}
	489
	490	return ret;
	491	}
	492	EXPORT_SYMBOL_GPL(cpuidle_register);
	493
4f86d3a8 LB	494	#ifdef CONFIG_SMP
	495
	496	static void smp_callback(void *v)
	497	{
	498	/* we already woke the CPU up, nothing more to do */
	499	}
	500
	501	/*
	502	* This function gets called when a part of the kernel has a new latency
	503	* requirement. This means we need to get all processors out of their C-state,
	504	* and then recalculate a new suitable C-state. Just do a cross-cpu IPI; that
	505	* wakes them all right up.
	506	*/
	507	static int cpuidle_latency_notify(struct notifier_block *b,
	508	unsigned long l, void *v)
	509	{
8691e5a8	510	smp_call_function(smp_callback, NULL, 1);
4f86d3a8 LB	511	return NOTIFY_OK;
	512	}
	513
	514	static struct notifier_block cpuidle_latency_notifier = {
	515	.notifier_call = cpuidle_latency_notify,
	516	};
	517
d82b3518 MG	518	static inline void latency_notifier_init(struct notifier_block *n)
	519	{
	520	pm_qos_add_notifier(PM_QOS_CPU_DMA_LATENCY, n);
	521	}
4f86d3a8 LB	522
	523	#else /* CONFIG_SMP */
	524
	525	#define latency_notifier_init(x) do { } while (0)
	526
	527	#endif /* CONFIG_SMP */
	528
	529	/**
	530	* cpuidle_init - core initializer
	531	*/
	532	static int __init cpuidle_init(void)
	533	{
	534	int ret;
	535
62027aea LB	536	if (cpuidle_disabled())
	537	return -ENODEV;
	538
8a25a2fd	539	ret = cpuidle_add_interface(cpu_subsys.dev_root);
4f86d3a8 LB	540	if (ret)
	541	return ret;
	542
	543	latency_notifier_init(&cpuidle_latency_notifier);
	544
	545	return 0;
	546	}
	547
62027aea	548	module_param(off, int, 0444);
4f86d3a8	549	core_initcall(cpuidle_init);