[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/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;
	}

	trace_cpu_idle_rcuidle(next_state, dev->cpu);

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

	if (broadcast)
		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 (broadcast)
		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);
}

/**
 * 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->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
76027ea8	143	trace_cpu_idle_rcuidle(next_state, dev->cpu);
f77cfe4e	144
fb11c9c6 VK	145	broadcast = !!(drv->states[next_state].flags & CPUIDLE_FLAG_TIMER_STOP);
	146
	147	if (broadcast)
6d281e97	148	clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER, &dev->cpu);
b60e6a0e	149
4126c019 CC	150	if (cpuidle_state_is_coupled(dev, drv, next_state))
	151	entered_state = cpuidle_enter_state_coupled(dev, drv,
	152	next_state);
	153	else
	154	entered_state = cpuidle_enter_state(dev, drv, next_state);
f77cfe4e	155
fb11c9c6	156	if (broadcast)
6d281e97	157	clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_EXIT, &dev->cpu);
b60e6a0e	158
76027ea8	159	trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, dev->cpu);
f77cfe4e	160
4f86d3a8 LB	161	/* give the governor an opportunity to reflect on the outcome */
4f86d3a8 LB	162	if (cpuidle_curr_governor->reflect)
e978aa7d	163	cpuidle_curr_governor->reflect(dev, entered_state);
a0bfa137 LB	164
a0bfa137 LB	165	return 0;
4f86d3a8 LB	166	}
	167
	168	/**
	169	* cpuidle_install_idle_handler - installs the cpuidle idle loop handler
	170	*/
	171	void cpuidle_install_idle_handler(void)
	172	{
a0bfa137	173	if (enabled_devices) {
4f86d3a8 LB	174	/* Make sure all changes finished before we switch to new idle */
4f86d3a8 LB	175	smp_wmb();
a0bfa137	176	initialized = 1;
4f86d3a8 LB	177	}
	178	}
	179
	180	/**
	181	* cpuidle_uninstall_idle_handler - uninstalls the cpuidle idle loop handler
	182	*/
	183	void cpuidle_uninstall_idle_handler(void)
	184	{
a0bfa137 LB	185	if (enabled_devices) {
a0bfa137 LB	186	initialized = 0;
4a162513	187	kick_all_cpus_sync();
4f86d3a8 LB	188	}
	189	}
	190
	191	/**
	192	* cpuidle_pause_and_lock - temporarily disables CPUIDLE
	193	*/
	194	void cpuidle_pause_and_lock(void)
	195	{
	196	mutex_lock(&cpuidle_lock);
	197	cpuidle_uninstall_idle_handler();
	198	}
	199
	200	EXPORT_SYMBOL_GPL(cpuidle_pause_and_lock);
	201
	202	/**
	203	* cpuidle_resume_and_unlock - resumes CPUIDLE operation
	204	*/
	205	void cpuidle_resume_and_unlock(void)
	206	{
	207	cpuidle_install_idle_handler();
	208	mutex_unlock(&cpuidle_lock);
	209	}
	210
	211	EXPORT_SYMBOL_GPL(cpuidle_resume_and_unlock);
	212
8651f97b PM	213	/* Currently used in suspend/resume path to suspend cpuidle */
	214	void cpuidle_pause(void)
	215	{
	216	mutex_lock(&cpuidle_lock);
	217	cpuidle_uninstall_idle_handler();
	218	mutex_unlock(&cpuidle_lock);
	219	}
	220
	221	/* Currently used in suspend/resume path to resume cpuidle */
	222	void cpuidle_resume(void)
	223	{
	224	mutex_lock(&cpuidle_lock);
	225	cpuidle_install_idle_handler();
	226	mutex_unlock(&cpuidle_lock);
	227	}
	228
4f86d3a8 LB	229	/**
	230	* cpuidle_enable_device - enables idle PM for a CPU
	231	* @dev: the CPU
	232	*
	233	* This function must be called between cpuidle_pause_and_lock and
	234	* cpuidle_resume_and_unlock when used externally.
	235	*/
	236	int cpuidle_enable_device(struct cpuidle_device *dev)
	237	{
5df0aa73	238	int ret;
bf4d1b5d	239	struct cpuidle_driver *drv;
4f86d3a8	240
1b0a0e9a SB	241	if (!dev)
	242	return -EINVAL;
	243
4f86d3a8 LB	244	if (dev->enabled)
4f86d3a8 LB	245	return 0;
bf4d1b5d DL	246
	247	drv = cpuidle_get_cpu_driver(dev);
	248
e1689795	249	if (!drv \|\| !cpuidle_curr_governor)
4f86d3a8	250	return -EIO;
bf4d1b5d	251
10b9d3f8 DL	252	if (!dev->registered)
	253	return -EINVAL;
	254
4f86d3a8	255	if (!dev->state_count)
fc850f39	256	dev->state_count = drv->state_count;
4f86d3a8	257
bf4d1b5d DL	258	ret = cpuidle_add_device_sysfs(dev);
bf4d1b5d DL	259	if (ret)
4f86d3a8 LB	260	return ret;
	261
	262	if (cpuidle_curr_governor->enable &&
e1689795	263	(ret = cpuidle_curr_governor->enable(drv, dev)))
4f86d3a8 LB	264	goto fail_sysfs;
4f86d3a8 LB	265
4f86d3a8 LB	266	smp_wmb();
	267
	268	dev->enabled = 1;
	269
	270	enabled_devices++;
	271	return 0;
	272
	273	fail_sysfs:
bf4d1b5d	274	cpuidle_remove_device_sysfs(dev);
4f86d3a8 LB	275
	276	return ret;
	277	}
	278
	279	EXPORT_SYMBOL_GPL(cpuidle_enable_device);
	280
	281	/**
	282	* cpuidle_disable_device - disables idle PM for a CPU
	283	* @dev: the CPU
	284	*
	285	* This function must be called between cpuidle_pause_and_lock and
	286	* cpuidle_resume_and_unlock when used externally.
	287	*/
	288	void cpuidle_disable_device(struct cpuidle_device *dev)
	289	{
bf4d1b5d DL	290	struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);
bf4d1b5d DL	291
cf31cd1a	292	if (!dev \|\| !dev->enabled)
4f86d3a8	293	return;
bf4d1b5d DL	294
bf4d1b5d DL	295	if (!drv \|\| !cpuidle_curr_governor)
4f86d3a8 LB	296	return;
	297
	298	dev->enabled = 0;
	299
	300	if (cpuidle_curr_governor->disable)
bf4d1b5d	301	cpuidle_curr_governor->disable(drv, dev);
4f86d3a8	302
bf4d1b5d	303	cpuidle_remove_device_sysfs(dev);
4f86d3a8 LB	304	enabled_devices--;
	305	}
	306
	307	EXPORT_SYMBOL_GPL(cpuidle_disable_device);
	308
f6bb51a5 DL	309	static void __cpuidle_unregister_device(struct cpuidle_device *dev)
	310	{
	311	struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);
	312
	313	list_del(&dev->device_list);
	314	per_cpu(cpuidle_devices, dev->cpu) = NULL;
	315	module_put(drv->owner);
	316	}
	317
267d4bf8	318	static void __cpuidle_device_init(struct cpuidle_device *dev)
5df0aa73 DL	319	{
	320	memset(dev->states_usage, 0, sizeof(dev->states_usage));
	321	dev->last_residency = 0;
5df0aa73 DL	322	}
5df0aa73 DL	323
4f86d3a8	324	/**
dcb84f33 VP	325	* __cpuidle_register_device - internal register function called before register
dcb84f33 VP	326	* and enable routines
4f86d3a8	327	* @dev: the cpu
dcb84f33 VP	328	*
dcb84f33 VP	329	* cpuidle_lock mutex must be held before this is called
4f86d3a8	330	*/
dcb84f33	331	static int __cpuidle_register_device(struct cpuidle_device *dev)
4f86d3a8 LB	332	{
4f86d3a8 LB	333	int ret;
bf4d1b5d	334	struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);
4f86d3a8	335
bf4d1b5d	336	if (!try_module_get(drv->owner))
4f86d3a8 LB	337	return -EINVAL;
4f86d3a8 LB	338
4f86d3a8 LB	339	per_cpu(cpuidle_devices, dev->cpu) = dev;
4f86d3a8 LB	340	list_add(&dev->device_list, &cpuidle_detected_devices);
4f86d3a8	341
4126c019	342	ret = cpuidle_coupled_register_device(dev);
47182668	343	if (ret)
f6bb51a5	344	__cpuidle_unregister_device(dev);
47182668 VK	345	else
47182668 VK	346	dev->registered = 1;
4f86d3a8	347
47182668	348	return ret;
dcb84f33 VP	349	}
	350
	351	/**
	352	* cpuidle_register_device - registers a CPU's idle PM feature
	353	* @dev: the cpu
	354	*/
	355	int cpuidle_register_device(struct cpuidle_device *dev)
	356	{
c878a52d	357	int ret = -EBUSY;
dcb84f33	358
1b0a0e9a SB	359	if (!dev)
	360	return -EINVAL;
	361
dcb84f33 VP	362	mutex_lock(&cpuidle_lock);
dcb84f33 VP	363
c878a52d DL	364	if (dev->registered)
	365	goto out_unlock;
	366
267d4bf8	367	__cpuidle_device_init(dev);
5df0aa73	368
f6bb51a5 DL	369	ret = __cpuidle_register_device(dev);
	370	if (ret)
	371	goto out_unlock;
	372
	373	ret = cpuidle_add_sysfs(dev);
	374	if (ret)
	375	goto out_unregister;
dcb84f33	376
10b9d3f8	377	ret = cpuidle_enable_device(dev);
f6bb51a5 DL	378	if (ret)
f6bb51a5 DL	379	goto out_sysfs;
10b9d3f8	380
4f86d3a8 LB	381	cpuidle_install_idle_handler();
4f86d3a8 LB	382
f6bb51a5	383	out_unlock:
4f86d3a8 LB	384	mutex_unlock(&cpuidle_lock);
4f86d3a8 LB	385
f6bb51a5 DL	386	return ret;
	387
	388	out_sysfs:
	389	cpuidle_remove_sysfs(dev);
	390	out_unregister:
	391	__cpuidle_unregister_device(dev);
	392	goto out_unlock;
4f86d3a8 LB	393	}
	394
	395	EXPORT_SYMBOL_GPL(cpuidle_register_device);
	396
	397	/**
	398	* cpuidle_unregister_device - unregisters a CPU's idle PM feature
	399	* @dev: the cpu
	400	*/
	401	void cpuidle_unregister_device(struct cpuidle_device *dev)
	402	{
dcb84f33 VP	403	if (dev->registered == 0)
	404	return;
	405
4f86d3a8 LB	406	cpuidle_pause_and_lock();
	407
	408	cpuidle_disable_device(dev);
	409
1aef40e2	410	cpuidle_remove_sysfs(dev);
f6bb51a5 DL	411
f6bb51a5 DL	412	__cpuidle_unregister_device(dev);
4f86d3a8	413
4126c019 CC	414	cpuidle_coupled_unregister_device(dev);
4126c019 CC	415
4f86d3a8	416	cpuidle_resume_and_unlock();
4f86d3a8 LB	417	}
	418
	419	EXPORT_SYMBOL_GPL(cpuidle_unregister_device);
	420
1c192d04	421	/**
4c637b21 DL	422	* cpuidle_unregister: unregister a driver and the devices. This function
	423	* can be used only if the driver has been previously registered through
	424	* the cpuidle_register function.
	425	*
	426	* @drv: a valid pointer to a struct cpuidle_driver
	427	*/
	428	void cpuidle_unregister(struct cpuidle_driver *drv)
	429	{
	430	int cpu;
	431	struct cpuidle_device *device;
	432
82467a5a	433	for_each_cpu(cpu, drv->cpumask) {
4c637b21 DL	434	device = &per_cpu(cpuidle_dev, cpu);
	435	cpuidle_unregister_device(device);
	436	}
	437
	438	cpuidle_unregister_driver(drv);
	439	}
	440	EXPORT_SYMBOL_GPL(cpuidle_unregister);
	441
	442	/**
	443	* cpuidle_register: registers the driver and the cpu devices with the
	444	* coupled_cpus passed as parameter. This function is used for all common
	445	* initialization pattern there are in the arch specific drivers. The
	446	* devices is globally defined in this file.
	447	*
	448	* @drv : a valid pointer to a struct cpuidle_driver
	449	* @coupled_cpus: a cpumask for the coupled states
	450	*
	451	* Returns 0 on success, < 0 otherwise
	452	*/
	453	int cpuidle_register(struct cpuidle_driver *drv,
	454	const struct cpumask *const coupled_cpus)
	455	{
	456	int ret, cpu;
	457	struct cpuidle_device *device;
	458
	459	ret = cpuidle_register_driver(drv);
	460	if (ret) {
	461	pr_err("failed to register cpuidle driver\n");
	462	return ret;
	463	}
	464
82467a5a	465	for_each_cpu(cpu, drv->cpumask) {
4c637b21 DL	466	device = &per_cpu(cpuidle_dev, cpu);
	467	device->cpu = cpu;
	468
	469	#ifdef CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED
	470	/*
caf4a36e	471	* On multiplatform for ARM, the coupled idle states could be
4c637b21 DL	472	* enabled in the kernel even if the cpuidle driver does not
	473	* use it. Note, coupled_cpus is a struct copy.
	474	*/
	475	if (coupled_cpus)
	476	device->coupled_cpus = *coupled_cpus;
	477	#endif
	478	ret = cpuidle_register_device(device);
	479	if (!ret)
	480	continue;
	481
	482	pr_err("Failed to register cpuidle device for cpu%d\n", cpu);
	483
	484	cpuidle_unregister(drv);
	485	break;
	486	}
	487
	488	return ret;
	489	}
	490	EXPORT_SYMBOL_GPL(cpuidle_register);
	491
4f86d3a8 LB	492	#ifdef CONFIG_SMP
	493
	494	static void smp_callback(void *v)
	495	{
	496	/* we already woke the CPU up, nothing more to do */
	497	}
	498
	499	/*
	500	* This function gets called when a part of the kernel has a new latency
	501	* requirement. This means we need to get all processors out of their C-state,
	502	* and then recalculate a new suitable C-state. Just do a cross-cpu IPI; that
	503	* wakes them all right up.
	504	*/
	505	static int cpuidle_latency_notify(struct notifier_block *b,
	506	unsigned long l, void *v)
	507	{
8691e5a8	508	smp_call_function(smp_callback, NULL, 1);
4f86d3a8 LB	509	return NOTIFY_OK;
	510	}
	511
	512	static struct notifier_block cpuidle_latency_notifier = {
	513	.notifier_call = cpuidle_latency_notify,
	514	};
	515
d82b3518 MG	516	static inline void latency_notifier_init(struct notifier_block *n)
	517	{
	518	pm_qos_add_notifier(PM_QOS_CPU_DMA_LATENCY, n);
	519	}
4f86d3a8 LB	520
	521	#else /* CONFIG_SMP */
	522
	523	#define latency_notifier_init(x) do { } while (0)
	524
	525	#endif /* CONFIG_SMP */
	526
	527	/**
	528	* cpuidle_init - core initializer
	529	*/
	530	static int __init cpuidle_init(void)
	531	{
	532	int ret;
	533
62027aea LB	534	if (cpuidle_disabled())
	535	return -ENODEV;
	536
8a25a2fd	537	ret = cpuidle_add_interface(cpu_subsys.dev_root);
4f86d3a8 LB	538	if (ret)
	539	return ret;
	540
	541	latency_notifier_init(&cpuidle_latency_notifier);
	542
	543	return 0;
	544	}
	545
62027aea	546	module_param(off, int, 0444);
4f86d3a8	547	core_initcall(cpuidle_init);