[mirror_ubuntu-jammy-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;
static bool use_deepest_state __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_use_deepest_state - Enable/disable the "deepest idle" mode.
 * @enable: Whether enable or disable the feature.
 *
 * If the "deepest idle" mode is enabled, cpuidle will ignore the governor and
 * always use the state with the greatest exit latency (out of the states that
 * are not disabled).
 *
 * This function can only be called after cpuidle_pause() to avoid races.
 */
void cpuidle_use_deepest_state(bool enable)
{
	use_deepest_state = enable;
}

/**
 * cpuidle_find_deepest_state - Find the state of the greatest exit latency.
 * @drv: cpuidle driver for a given CPU.
 * @dev: cpuidle device for a given CPU.
 */
static int cpuidle_find_deepest_state(struct cpuidle_driver *drv,
				      struct cpuidle_device *dev)
{
	unsigned int latency_req = 0;
	int i, ret = CPUIDLE_DRIVER_STATE_START - 1;

	for (i = CPUIDLE_DRIVER_STATE_START; i < drv->state_count; i++) {
		struct cpuidle_state *s = &drv->states[i];
		struct cpuidle_state_usage *su = &dev->states_usage[i];

		if (s->disabled || su->disable || s->exit_latency <= latency_req)
			continue;

		latency_req = s->exit_latency;
		ret = i;
	}
	return ret;
}

/**
 * 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;

	trace_cpu_idle_rcuidle(index, dev->cpu);
	time_start = ktime_get();

	entered_state = target_state->enter(dev, drv, index);

	time_end = ktime_get();
	trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, dev->cpu);

	if (!cpuidle_state_is_coupled(dev, drv, entered_state))
		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_select - ask the cpuidle framework to choose an idle state
 *
 * @drv: the cpuidle driver
 * @dev: the cpuidle device
 *
 * Returns the index of the idle state.
 */
int cpuidle_select(struct cpuidle_driver *drv, struct cpuidle_device *dev)
{
	if (off || !initialized)
		return -ENODEV;

	if (!drv || !dev || !dev->enabled)
		return -EBUSY;

	if (unlikely(use_deepest_state))
		return cpuidle_find_deepest_state(drv, dev);

	return cpuidle_curr_governor->select(drv, dev);
}

/**
 * cpuidle_enter - enter into the specified idle state
 *
 * @drv:   the cpuidle driver tied with the cpu
 * @dev:   the cpuidle device
 * @index: the index in the idle state table
 *
 * Returns the index in the idle state, < 0 in case of error.
 * The error code depends on the backend driver
 */
int cpuidle_enter(struct cpuidle_driver *drv, struct cpuidle_device *dev,
		  int index)
{
	if (cpuidle_state_is_coupled(dev, drv, index))
		return cpuidle_enter_state_coupled(dev, drv, index);
	return cpuidle_enter_state(dev, drv, index);
}

/**
 * cpuidle_reflect - tell the underlying governor what was the state
 * we were in
 *
 * @dev  : the cpuidle device
 * @index: the index in the idle state table
 *
 */
void cpuidle_reflect(struct cpuidle_device *dev, int index)
{
	if (cpuidle_curr_governor->reflect && !unlikely(use_deepest_state))
		cpuidle_curr_governor->reflect(dev, index);
}

/**
 * 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;
		wake_up_all_idle_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);

/* 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

/*
 * 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)
{
	wake_up_all_idle_cpus();
	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;
a6220fc1	35	static bool use_deepest_state __read_mostly;
62027aea LB	36
	37	int cpuidle_disabled(void)
	38	{
	39	return off;
	40	}
d91ee586 LB	41	void disable_cpuidle(void)
	42	{
	43	off = 1;
	44	}
4f86d3a8	45
1a022e3f BO	46	/**
	47	* cpuidle_play_dead - cpu off-lining
	48	*
ee01e663	49	* Returns in case of an error or no driver
1a022e3f BO	50	*/
	51	int cpuidle_play_dead(void)
	52	{
	53	struct cpuidle_device *dev = __this_cpu_read(cpuidle_devices);
bf4d1b5d	54	struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);
8aef33a7	55	int i;
1a022e3f	56
ee01e663 TK	57	if (!drv)
	58	return -ENODEV;
	59
1a022e3f	60	/* Find lowest-power state that supports long-term idle */
8aef33a7 DL	61	for (i = drv->state_count - 1; i >= CPUIDLE_DRIVER_STATE_START; i--)
	62	if (drv->states[i].enter_dead)
	63	return drv->states[i].enter_dead(dev, i);
1a022e3f BO	64
	65	return -ENODEV;
	66	}
	67
a6220fc1 RW	68	/**
	69	* cpuidle_use_deepest_state - Enable/disable the "deepest idle" mode.
	70	* @enable: Whether enable or disable the feature.
	71	*
	72	* If the "deepest idle" mode is enabled, cpuidle will ignore the governor and
	73	* always use the state with the greatest exit latency (out of the states that
	74	* are not disabled).
	75	*
	76	* This function can only be called after cpuidle_pause() to avoid races.
	77	*/
	78	void cpuidle_use_deepest_state(bool enable)
	79	{
	80	use_deepest_state = enable;
	81	}
	82
	83	/**
	84	* cpuidle_find_deepest_state - Find the state of the greatest exit latency.
	85	* @drv: cpuidle driver for a given CPU.
	86	* @dev: cpuidle device for a given CPU.
	87	*/
	88	static int cpuidle_find_deepest_state(struct cpuidle_driver *drv,
	89	struct cpuidle_device *dev)
	90	{
	91	unsigned int latency_req = 0;
	92	int i, ret = CPUIDLE_DRIVER_STATE_START - 1;
	93
	94	for (i = CPUIDLE_DRIVER_STATE_START; i < drv->state_count; i++) {
	95	struct cpuidle_state *s = &drv->states[i];
	96	struct cpuidle_state_usage *su = &dev->states_usage[i];
	97
	98	if (s->disabled \|\| su->disable \|\| s->exit_latency <= latency_req)
	99	continue;
	100
	101	latency_req = s->exit_latency;
	102	ret = i;
	103	}
	104	return ret;
	105	}
	106
56cfbf74 CC	107	/**
	108	* cpuidle_enter_state - enter the state and update stats
	109	* @dev: cpuidle device for this cpu
	110	* @drv: cpuidle driver for this cpu
	111	* @next_state: index into drv->states of the state to enter
	112	*/
	113	int cpuidle_enter_state(struct cpuidle_device dev, struct cpuidle_driver drv,
554c06ba	114	int index)
56cfbf74 CC	115	{
	116	int entered_state;
	117
554c06ba DL	118	struct cpuidle_state *target_state = &drv->states[index];
	119	ktime_t time_start, time_end;
	120	s64 diff;
	121
30fe6884	122	trace_cpu_idle_rcuidle(index, dev->cpu);
554c06ba DL	123	time_start = ktime_get();
	124
	125	entered_state = target_state->enter(dev, drv, index);
	126
	127	time_end = ktime_get();
30fe6884	128	trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, dev->cpu);
554c06ba	129
0b89e9aa PB	130	if (!cpuidle_state_is_coupled(dev, drv, entered_state))
0b89e9aa PB	131	local_irq_enable();
554c06ba DL	132
	133	diff = ktime_to_us(ktime_sub(time_end, time_start));
	134	if (diff > INT_MAX)
	135	diff = INT_MAX;
	136
	137	dev->last_residency = (int) diff;
56cfbf74 CC	138
	139	if (entered_state >= 0) {
	140	/* Update cpuidle counters */
	141	/* This can be moved to within driver enter routine
	142	* but that results in multiple copies of same code.
	143	*/
a474a515	144	dev->states_usage[entered_state].time += dev->last_residency;
56cfbf74 CC	145	dev->states_usage[entered_state].usage++;
	146	} else {
	147	dev->last_residency = 0;
	148	}
	149
	150	return entered_state;
	151	}
	152
4f86d3a8	153	/**
907e30f1 DL	154	* cpuidle_select - ask the cpuidle framework to choose an idle state
	155	*
	156	* @drv: the cpuidle driver
	157	* @dev: the cpuidle device
4f86d3a8	158	*
907e30f1	159	* Returns the index of the idle state.
4f86d3a8	160	*/
907e30f1	161	int cpuidle_select(struct cpuidle_driver drv, struct cpuidle_device dev)
4f86d3a8	162	{
52c324f8 RW	163	if (off \|\| !initialized)
	164	return -ENODEV;
	165
	166	if (!drv \|\| !dev \|\| !dev->enabled)
	167	return -EBUSY;
	168
a6220fc1 RW	169	if (unlikely(use_deepest_state))
	170	return cpuidle_find_deepest_state(drv, dev);
	171
907e30f1 DL	172	return cpuidle_curr_governor->select(drv, dev);
907e30f1 DL	173	}
ba8f20c2	174
907e30f1 DL	175	/**
	176	* cpuidle_enter - enter into the specified idle state
	177	*
	178	* @drv: the cpuidle driver tied with the cpu
	179	* @dev: the cpuidle device
	180	* @index: the index in the idle state table
	181	*
	182	* Returns the index in the idle state, < 0 in case of error.
	183	* The error code depends on the backend driver
	184	*/
	185	int cpuidle_enter(struct cpuidle_driver drv, struct cpuidle_device dev,
	186	int index)
	187	{
	188	if (cpuidle_state_is_coupled(dev, drv, index))
	189	return cpuidle_enter_state_coupled(dev, drv, index);
	190	return cpuidle_enter_state(dev, drv, index);
	191	}
b60e6a0e	192
907e30f1 DL	193	/**
	194	* cpuidle_reflect - tell the underlying governor what was the state
	195	* we were in
	196	*
	197	* @dev : the cpuidle device
	198	* @index: the index in the idle state table
	199	*
	200	*/
	201	void cpuidle_reflect(struct cpuidle_device *dev, int index)
	202	{
a6220fc1	203	if (cpuidle_curr_governor->reflect && !unlikely(use_deepest_state))
907e30f1	204	cpuidle_curr_governor->reflect(dev, index);
4f86d3a8 LB	205	}
	206
	207	/**
	208	* cpuidle_install_idle_handler - installs the cpuidle idle loop handler
	209	*/
	210	void cpuidle_install_idle_handler(void)
	211	{
a0bfa137	212	if (enabled_devices) {
4f86d3a8 LB	213	/* Make sure all changes finished before we switch to new idle */
4f86d3a8 LB	214	smp_wmb();
a0bfa137	215	initialized = 1;
4f86d3a8 LB	216	}
	217	}
	218
	219	/**
	220	* cpuidle_uninstall_idle_handler - uninstalls the cpuidle idle loop handler
	221	*/
	222	void cpuidle_uninstall_idle_handler(void)
	223	{
a0bfa137 LB	224	if (enabled_devices) {
a0bfa137 LB	225	initialized = 0;
2ed903c5	226	wake_up_all_idle_cpus();
4f86d3a8 LB	227	}
	228	}
	229
	230	/**
	231	* cpuidle_pause_and_lock - temporarily disables CPUIDLE
	232	*/
	233	void cpuidle_pause_and_lock(void)
	234	{
	235	mutex_lock(&cpuidle_lock);
	236	cpuidle_uninstall_idle_handler();
	237	}
	238
	239	EXPORT_SYMBOL_GPL(cpuidle_pause_and_lock);
	240
	241	/**
	242	* cpuidle_resume_and_unlock - resumes CPUIDLE operation
	243	*/
	244	void cpuidle_resume_and_unlock(void)
	245	{
	246	cpuidle_install_idle_handler();
	247	mutex_unlock(&cpuidle_lock);
	248	}
	249
	250	EXPORT_SYMBOL_GPL(cpuidle_resume_and_unlock);
	251
8651f97b PM	252	/* Currently used in suspend/resume path to suspend cpuidle */
	253	void cpuidle_pause(void)
	254	{
	255	mutex_lock(&cpuidle_lock);
	256	cpuidle_uninstall_idle_handler();
	257	mutex_unlock(&cpuidle_lock);
	258	}
	259
	260	/* Currently used in suspend/resume path to resume cpuidle */
	261	void cpuidle_resume(void)
	262	{
	263	mutex_lock(&cpuidle_lock);
	264	cpuidle_install_idle_handler();
	265	mutex_unlock(&cpuidle_lock);
	266	}
	267
4f86d3a8 LB	268	/**
	269	* cpuidle_enable_device - enables idle PM for a CPU
	270	* @dev: the CPU
	271	*
	272	* This function must be called between cpuidle_pause_and_lock and
	273	* cpuidle_resume_and_unlock when used externally.
	274	*/
	275	int cpuidle_enable_device(struct cpuidle_device *dev)
	276	{
5df0aa73	277	int ret;
bf4d1b5d	278	struct cpuidle_driver *drv;
4f86d3a8	279
1b0a0e9a SB	280	if (!dev)
	281	return -EINVAL;
	282
4f86d3a8 LB	283	if (dev->enabled)
4f86d3a8 LB	284	return 0;
bf4d1b5d DL	285
	286	drv = cpuidle_get_cpu_driver(dev);
	287
e1689795	288	if (!drv \|\| !cpuidle_curr_governor)
4f86d3a8	289	return -EIO;
bf4d1b5d	290
10b9d3f8 DL	291	if (!dev->registered)
	292	return -EINVAL;
	293
4f86d3a8	294	if (!dev->state_count)
fc850f39	295	dev->state_count = drv->state_count;
4f86d3a8	296
bf4d1b5d DL	297	ret = cpuidle_add_device_sysfs(dev);
bf4d1b5d DL	298	if (ret)
4f86d3a8 LB	299	return ret;
	300
	301	if (cpuidle_curr_governor->enable &&
e1689795	302	(ret = cpuidle_curr_governor->enable(drv, dev)))
4f86d3a8 LB	303	goto fail_sysfs;
4f86d3a8 LB	304
4f86d3a8 LB	305	smp_wmb();
	306
	307	dev->enabled = 1;
	308
	309	enabled_devices++;
	310	return 0;
	311
	312	fail_sysfs:
bf4d1b5d	313	cpuidle_remove_device_sysfs(dev);
4f86d3a8 LB	314
	315	return ret;
	316	}
	317
	318	EXPORT_SYMBOL_GPL(cpuidle_enable_device);
	319
	320	/**
	321	* cpuidle_disable_device - disables idle PM for a CPU
	322	* @dev: the CPU
	323	*
	324	* This function must be called between cpuidle_pause_and_lock and
	325	* cpuidle_resume_and_unlock when used externally.
	326	*/
	327	void cpuidle_disable_device(struct cpuidle_device *dev)
	328	{
bf4d1b5d DL	329	struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);
bf4d1b5d DL	330
cf31cd1a	331	if (!dev \|\| !dev->enabled)
4f86d3a8	332	return;
bf4d1b5d DL	333
bf4d1b5d DL	334	if (!drv \|\| !cpuidle_curr_governor)
4f86d3a8 LB	335	return;
	336
	337	dev->enabled = 0;
	338
	339	if (cpuidle_curr_governor->disable)
bf4d1b5d	340	cpuidle_curr_governor->disable(drv, dev);
4f86d3a8	341
bf4d1b5d	342	cpuidle_remove_device_sysfs(dev);
4f86d3a8 LB	343	enabled_devices--;
	344	}
	345
	346	EXPORT_SYMBOL_GPL(cpuidle_disable_device);
	347
f6bb51a5 DL	348	static void __cpuidle_unregister_device(struct cpuidle_device *dev)
	349	{
	350	struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);
	351
	352	list_del(&dev->device_list);
	353	per_cpu(cpuidle_devices, dev->cpu) = NULL;
	354	module_put(drv->owner);
	355	}
	356
267d4bf8	357	static void __cpuidle_device_init(struct cpuidle_device *dev)
5df0aa73 DL	358	{
	359	memset(dev->states_usage, 0, sizeof(dev->states_usage));
	360	dev->last_residency = 0;
5df0aa73 DL	361	}
5df0aa73 DL	362
4f86d3a8	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);
4f86d3a8	380
4126c019	381	ret = cpuidle_coupled_register_device(dev);
47182668	382	if (ret)
f6bb51a5	383	__cpuidle_unregister_device(dev);
47182668 VK	384	else
47182668 VK	385	dev->registered = 1;
4f86d3a8	386
47182668	387	return ret;
dcb84f33 VP	388	}
	389
	390	/**
	391	* cpuidle_register_device - registers a CPU's idle PM feature
	392	* @dev: the cpu
	393	*/
	394	int cpuidle_register_device(struct cpuidle_device *dev)
	395	{
c878a52d	396	int ret = -EBUSY;
dcb84f33	397
1b0a0e9a SB	398	if (!dev)
	399	return -EINVAL;
	400
dcb84f33 VP	401	mutex_lock(&cpuidle_lock);
dcb84f33 VP	402
c878a52d DL	403	if (dev->registered)
	404	goto out_unlock;
	405
267d4bf8	406	__cpuidle_device_init(dev);
5df0aa73	407
f6bb51a5 DL	408	ret = __cpuidle_register_device(dev);
	409	if (ret)
	410	goto out_unlock;
	411
	412	ret = cpuidle_add_sysfs(dev);
	413	if (ret)
	414	goto out_unregister;
dcb84f33	415
10b9d3f8	416	ret = cpuidle_enable_device(dev);
f6bb51a5 DL	417	if (ret)
f6bb51a5 DL	418	goto out_sysfs;
10b9d3f8	419
4f86d3a8 LB	420	cpuidle_install_idle_handler();
4f86d3a8 LB	421
f6bb51a5	422	out_unlock:
4f86d3a8 LB	423	mutex_unlock(&cpuidle_lock);
4f86d3a8 LB	424
f6bb51a5 DL	425	return ret;
	426
	427	out_sysfs:
	428	cpuidle_remove_sysfs(dev);
	429	out_unregister:
	430	__cpuidle_unregister_device(dev);
	431	goto out_unlock;
4f86d3a8 LB	432	}
	433
	434	EXPORT_SYMBOL_GPL(cpuidle_register_device);
	435
	436	/**
	437	* cpuidle_unregister_device - unregisters a CPU's idle PM feature
	438	* @dev: the cpu
	439	*/
	440	void cpuidle_unregister_device(struct cpuidle_device *dev)
	441	{
813e8e3d	442	if (!dev \|\| dev->registered == 0)
dcb84f33 VP	443	return;
dcb84f33 VP	444
4f86d3a8 LB	445	cpuidle_pause_and_lock();
	446
	447	cpuidle_disable_device(dev);
	448
1aef40e2	449	cpuidle_remove_sysfs(dev);
f6bb51a5 DL	450
f6bb51a5 DL	451	__cpuidle_unregister_device(dev);
4f86d3a8	452
4126c019 CC	453	cpuidle_coupled_unregister_device(dev);
4126c019 CC	454
4f86d3a8	455	cpuidle_resume_and_unlock();
4f86d3a8 LB	456	}
	457
	458	EXPORT_SYMBOL_GPL(cpuidle_unregister_device);
	459
1c192d04	460	/**
4c637b21 DL	461	* cpuidle_unregister: unregister a driver and the devices. This function
	462	* can be used only if the driver has been previously registered through
	463	* the cpuidle_register function.
	464	*
	465	* @drv: a valid pointer to a struct cpuidle_driver
	466	*/
	467	void cpuidle_unregister(struct cpuidle_driver *drv)
	468	{
	469	int cpu;
	470	struct cpuidle_device *device;
	471
82467a5a	472	for_each_cpu(cpu, drv->cpumask) {
4c637b21 DL	473	device = &per_cpu(cpuidle_dev, cpu);
	474	cpuidle_unregister_device(device);
	475	}
	476
	477	cpuidle_unregister_driver(drv);
	478	}
	479	EXPORT_SYMBOL_GPL(cpuidle_unregister);
	480
	481	/**
	482	* cpuidle_register: registers the driver and the cpu devices with the
	483	* coupled_cpus passed as parameter. This function is used for all common
	484	* initialization pattern there are in the arch specific drivers. The
	485	* devices is globally defined in this file.
	486	*
	487	* @drv : a valid pointer to a struct cpuidle_driver
	488	* @coupled_cpus: a cpumask for the coupled states
	489	*
	490	* Returns 0 on success, < 0 otherwise
	491	*/
	492	int cpuidle_register(struct cpuidle_driver *drv,
	493	const struct cpumask *const coupled_cpus)
	494	{
	495	int ret, cpu;
	496	struct cpuidle_device *device;
	497
	498	ret = cpuidle_register_driver(drv);
	499	if (ret) {
	500	pr_err("failed to register cpuidle driver\n");
	501	return ret;
	502	}
	503
82467a5a	504	for_each_cpu(cpu, drv->cpumask) {
4c637b21 DL	505	device = &per_cpu(cpuidle_dev, cpu);
	506	device->cpu = cpu;
	507
	508	#ifdef CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED
	509	/*
caf4a36e	510	* On multiplatform for ARM, the coupled idle states could be
4c637b21 DL	511	* enabled in the kernel even if the cpuidle driver does not
	512	* use it. Note, coupled_cpus is a struct copy.
	513	*/
	514	if (coupled_cpus)
	515	device->coupled_cpus = *coupled_cpus;
	516	#endif
	517	ret = cpuidle_register_device(device);
	518	if (!ret)
	519	continue;
	520
	521	pr_err("Failed to register cpuidle device for cpu%d\n", cpu);
	522
	523	cpuidle_unregister(drv);
	524	break;
	525	}
	526
	527	return ret;
	528	}
	529	EXPORT_SYMBOL_GPL(cpuidle_register);
	530
4f86d3a8 LB	531	#ifdef CONFIG_SMP
4f86d3a8 LB	532
4f86d3a8 LB	533	/*
	534	* This function gets called when a part of the kernel has a new latency
	535	* requirement. This means we need to get all processors out of their C-state,
	536	* and then recalculate a new suitable C-state. Just do a cross-cpu IPI; that
	537	* wakes them all right up.
	538	*/
	539	static int cpuidle_latency_notify(struct notifier_block *b,
	540	unsigned long l, void *v)
	541	{
2ed903c5	542	wake_up_all_idle_cpus();
4f86d3a8 LB	543	return NOTIFY_OK;
	544	}
	545
	546	static struct notifier_block cpuidle_latency_notifier = {
	547	.notifier_call = cpuidle_latency_notify,
	548	};
	549
d82b3518 MG	550	static inline void latency_notifier_init(struct notifier_block *n)
	551	{
	552	pm_qos_add_notifier(PM_QOS_CPU_DMA_LATENCY, n);
	553	}
4f86d3a8 LB	554
	555	#else /* CONFIG_SMP */
	556
	557	#define latency_notifier_init(x) do { } while (0)
	558
	559	#endif /* CONFIG_SMP */
	560
	561	/**
	562	* cpuidle_init - core initializer
	563	*/
	564	static int __init cpuidle_init(void)
	565	{
	566	int ret;
	567
62027aea LB	568	if (cpuidle_disabled())
	569	return -ENODEV;
	570
8a25a2fd	571	ret = cpuidle_add_interface(cpu_subsys.dev_root);
4f86d3a8 LB	572	if (ret)
	573	return ret;
	574
	575	latency_notifier_init(&cpuidle_latency_notifier);
	576
	577	return 0;
	578	}
	579
62027aea	580	module_param(off, int, 0444);
4f86d3a8	581	core_initcall(cpuidle_init);