[deliverable/linux.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_enabled - check if the cpuidle framework is ready
 * @dev: cpuidle device for this cpu
 * @drv: cpuidle driver for this cpu
 *
 * Return 0 on success, otherwise:
 * -NODEV : the cpuidle framework is not available
 * -EBUSY : the cpuidle framework is not initialized
 */
int cpuidle_enabled(struct cpuidle_driver *drv, struct cpuidle_device *dev)
{
	if (off || !initialized)
		return -ENODEV;

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

	return 0;
}

/**
 * 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();

	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)
{
	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)
		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;
		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
907e30f1 DL	67	/**
	68	* cpuidle_enabled - check if the cpuidle framework is ready
	69	* @dev: cpuidle device for this cpu
	70	* @drv: cpuidle driver for this cpu
	71	*
	72	* Return 0 on success, otherwise:
	73	* -NODEV : the cpuidle framework is not available
	74	* -EBUSY : the cpuidle framework is not initialized
	75	*/
	76	int cpuidle_enabled(struct cpuidle_driver drv, struct cpuidle_device dev)
	77	{
	78	if (off \|\| !initialized)
	79	return -ENODEV;
	80
	81	if (!drv \|\| !dev \|\| !dev->enabled)
	82	return -EBUSY;
	83
	84	return 0;
	85	}
	86
56cfbf74 CC	87	/**
	88	* cpuidle_enter_state - enter the state and update stats
	89	* @dev: cpuidle device for this cpu
	90	* @drv: cpuidle driver for this cpu
	91	* @next_state: index into drv->states of the state to enter
	92	*/
	93	int cpuidle_enter_state(struct cpuidle_device dev, struct cpuidle_driver drv,
554c06ba	94	int index)
56cfbf74 CC	95	{
	96	int entered_state;
	97
554c06ba DL	98	struct cpuidle_state *target_state = &drv->states[index];
	99	ktime_t time_start, time_end;
	100	s64 diff;
	101
	102	time_start = ktime_get();
	103
	104	entered_state = target_state->enter(dev, drv, index);
	105
	106	time_end = ktime_get();
	107
0b89e9aa PB	108	if (!cpuidle_state_is_coupled(dev, drv, entered_state))
0b89e9aa PB	109	local_irq_enable();
554c06ba DL	110
	111	diff = ktime_to_us(ktime_sub(time_end, time_start));
	112	if (diff > INT_MAX)
	113	diff = INT_MAX;
	114
	115	dev->last_residency = (int) diff;
56cfbf74 CC	116
	117	if (entered_state >= 0) {
	118	/* Update cpuidle counters */
	119	/* This can be moved to within driver enter routine
	120	* but that results in multiple copies of same code.
	121	*/
a474a515	122	dev->states_usage[entered_state].time += dev->last_residency;
56cfbf74 CC	123	dev->states_usage[entered_state].usage++;
	124	} else {
	125	dev->last_residency = 0;
	126	}
	127
	128	return entered_state;
	129	}
	130
4f86d3a8	131	/**
907e30f1 DL	132	* cpuidle_select - ask the cpuidle framework to choose an idle state
	133	*
	134	* @drv: the cpuidle driver
	135	* @dev: the cpuidle device
4f86d3a8	136	*
907e30f1	137	* Returns the index of the idle state.
4f86d3a8	138	*/
907e30f1	139	int cpuidle_select(struct cpuidle_driver drv, struct cpuidle_device dev)
4f86d3a8	140	{
907e30f1 DL	141	return cpuidle_curr_governor->select(drv, dev);
907e30f1 DL	142	}
ba8f20c2	143
907e30f1 DL	144	/**
	145	* cpuidle_enter - enter into the specified idle state
	146	*
	147	* @drv: the cpuidle driver tied with the cpu
	148	* @dev: the cpuidle device
	149	* @index: the index in the idle state table
	150	*
	151	* Returns the index in the idle state, < 0 in case of error.
	152	* The error code depends on the backend driver
	153	*/
	154	int cpuidle_enter(struct cpuidle_driver drv, struct cpuidle_device dev,
	155	int index)
	156	{
	157	if (cpuidle_state_is_coupled(dev, drv, index))
	158	return cpuidle_enter_state_coupled(dev, drv, index);
	159	return cpuidle_enter_state(dev, drv, index);
	160	}
b60e6a0e	161
907e30f1 DL	162	/**
	163	* cpuidle_reflect - tell the underlying governor what was the state
	164	* we were in
	165	*
	166	* @dev : the cpuidle device
	167	* @index: the index in the idle state table
	168	*
	169	*/
	170	void cpuidle_reflect(struct cpuidle_device *dev, int index)
	171	{
4f86d3a8	172	if (cpuidle_curr_governor->reflect)
907e30f1	173	cpuidle_curr_governor->reflect(dev, index);
4f86d3a8 LB	174	}
	175
	176	/**
	177	* cpuidle_install_idle_handler - installs the cpuidle idle loop handler
	178	*/
	179	void cpuidle_install_idle_handler(void)
	180	{
a0bfa137	181	if (enabled_devices) {
4f86d3a8 LB	182	/* Make sure all changes finished before we switch to new idle */
4f86d3a8 LB	183	smp_wmb();
a0bfa137	184	initialized = 1;
4f86d3a8 LB	185	}
	186	}
	187
	188	/**
	189	* cpuidle_uninstall_idle_handler - uninstalls the cpuidle idle loop handler
	190	*/
	191	void cpuidle_uninstall_idle_handler(void)
	192	{
a0bfa137 LB	193	if (enabled_devices) {
a0bfa137 LB	194	initialized = 0;
4a162513	195	kick_all_cpus_sync();
4f86d3a8 LB	196	}
	197	}
	198
	199	/**
	200	* cpuidle_pause_and_lock - temporarily disables CPUIDLE
	201	*/
	202	void cpuidle_pause_and_lock(void)
	203	{
	204	mutex_lock(&cpuidle_lock);
	205	cpuidle_uninstall_idle_handler();
	206	}
	207
	208	EXPORT_SYMBOL_GPL(cpuidle_pause_and_lock);
	209
	210	/**
	211	* cpuidle_resume_and_unlock - resumes CPUIDLE operation
	212	*/
	213	void cpuidle_resume_and_unlock(void)
	214	{
	215	cpuidle_install_idle_handler();
	216	mutex_unlock(&cpuidle_lock);
	217	}
	218
	219	EXPORT_SYMBOL_GPL(cpuidle_resume_and_unlock);
	220
8651f97b PM	221	/* Currently used in suspend/resume path to suspend cpuidle */
	222	void cpuidle_pause(void)
	223	{
	224	mutex_lock(&cpuidle_lock);
	225	cpuidle_uninstall_idle_handler();
	226	mutex_unlock(&cpuidle_lock);
	227	}
	228
	229	/* Currently used in suspend/resume path to resume cpuidle */
	230	void cpuidle_resume(void)
	231	{
	232	mutex_lock(&cpuidle_lock);
	233	cpuidle_install_idle_handler();
	234	mutex_unlock(&cpuidle_lock);
	235	}
	236
4f86d3a8 LB	237	/**
	238	* cpuidle_enable_device - enables idle PM for a CPU
	239	* @dev: the CPU
	240	*
	241	* This function must be called between cpuidle_pause_and_lock and
	242	* cpuidle_resume_and_unlock when used externally.
	243	*/
	244	int cpuidle_enable_device(struct cpuidle_device *dev)
	245	{
5df0aa73	246	int ret;
bf4d1b5d	247	struct cpuidle_driver *drv;
4f86d3a8	248
1b0a0e9a SB	249	if (!dev)
	250	return -EINVAL;
	251
4f86d3a8 LB	252	if (dev->enabled)
4f86d3a8 LB	253	return 0;
bf4d1b5d DL	254
	255	drv = cpuidle_get_cpu_driver(dev);
	256
e1689795	257	if (!drv \|\| !cpuidle_curr_governor)
4f86d3a8	258	return -EIO;
bf4d1b5d	259
10b9d3f8 DL	260	if (!dev->registered)
	261	return -EINVAL;
	262
4f86d3a8	263	if (!dev->state_count)
fc850f39	264	dev->state_count = drv->state_count;
4f86d3a8	265
bf4d1b5d DL	266	ret = cpuidle_add_device_sysfs(dev);
bf4d1b5d DL	267	if (ret)
4f86d3a8 LB	268	return ret;
	269
	270	if (cpuidle_curr_governor->enable &&
e1689795	271	(ret = cpuidle_curr_governor->enable(drv, dev)))
4f86d3a8 LB	272	goto fail_sysfs;
4f86d3a8 LB	273
4f86d3a8 LB	274	smp_wmb();
	275
	276	dev->enabled = 1;
	277
	278	enabled_devices++;
	279	return 0;
	280
	281	fail_sysfs:
bf4d1b5d	282	cpuidle_remove_device_sysfs(dev);
4f86d3a8 LB	283
	284	return ret;
	285	}
	286
	287	EXPORT_SYMBOL_GPL(cpuidle_enable_device);
	288
	289	/**
	290	* cpuidle_disable_device - disables idle PM for a CPU
	291	* @dev: the CPU
	292	*
	293	* This function must be called between cpuidle_pause_and_lock and
	294	* cpuidle_resume_and_unlock when used externally.
	295	*/
	296	void cpuidle_disable_device(struct cpuidle_device *dev)
	297	{
bf4d1b5d DL	298	struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);
bf4d1b5d DL	299
cf31cd1a	300	if (!dev \|\| !dev->enabled)
4f86d3a8	301	return;
bf4d1b5d DL	302
bf4d1b5d DL	303	if (!drv \|\| !cpuidle_curr_governor)
4f86d3a8 LB	304	return;
	305
	306	dev->enabled = 0;
	307
	308	if (cpuidle_curr_governor->disable)
bf4d1b5d	309	cpuidle_curr_governor->disable(drv, dev);
4f86d3a8	310
bf4d1b5d	311	cpuidle_remove_device_sysfs(dev);
4f86d3a8 LB	312	enabled_devices--;
	313	}
	314
	315	EXPORT_SYMBOL_GPL(cpuidle_disable_device);
	316
f6bb51a5 DL	317	static void __cpuidle_unregister_device(struct cpuidle_device *dev)
	318	{
	319	struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);
	320
	321	list_del(&dev->device_list);
	322	per_cpu(cpuidle_devices, dev->cpu) = NULL;
	323	module_put(drv->owner);
	324	}
	325
267d4bf8	326	static void __cpuidle_device_init(struct cpuidle_device *dev)
5df0aa73 DL	327	{
	328	memset(dev->states_usage, 0, sizeof(dev->states_usage));
	329	dev->last_residency = 0;
5df0aa73 DL	330	}
5df0aa73 DL	331
4f86d3a8	332	/**
dcb84f33 VP	333	* __cpuidle_register_device - internal register function called before register
dcb84f33 VP	334	* and enable routines
4f86d3a8	335	* @dev: the cpu
dcb84f33 VP	336	*
dcb84f33 VP	337	* cpuidle_lock mutex must be held before this is called
4f86d3a8	338	*/
dcb84f33	339	static int __cpuidle_register_device(struct cpuidle_device *dev)
4f86d3a8 LB	340	{
4f86d3a8 LB	341	int ret;
bf4d1b5d	342	struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);
4f86d3a8	343
bf4d1b5d	344	if (!try_module_get(drv->owner))
4f86d3a8 LB	345	return -EINVAL;
4f86d3a8 LB	346
4f86d3a8 LB	347	per_cpu(cpuidle_devices, dev->cpu) = dev;
4f86d3a8 LB	348	list_add(&dev->device_list, &cpuidle_detected_devices);
4f86d3a8	349
4126c019	350	ret = cpuidle_coupled_register_device(dev);
47182668	351	if (ret)
f6bb51a5	352	__cpuidle_unregister_device(dev);
47182668 VK	353	else
47182668 VK	354	dev->registered = 1;
4f86d3a8	355
47182668	356	return ret;
dcb84f33 VP	357	}
	358
	359	/**
	360	* cpuidle_register_device - registers a CPU's idle PM feature
	361	* @dev: the cpu
	362	*/
	363	int cpuidle_register_device(struct cpuidle_device *dev)
	364	{
c878a52d	365	int ret = -EBUSY;
dcb84f33	366
1b0a0e9a SB	367	if (!dev)
	368	return -EINVAL;
	369
dcb84f33 VP	370	mutex_lock(&cpuidle_lock);
dcb84f33 VP	371
c878a52d DL	372	if (dev->registered)
	373	goto out_unlock;
	374
267d4bf8	375	__cpuidle_device_init(dev);
5df0aa73	376
f6bb51a5 DL	377	ret = __cpuidle_register_device(dev);
	378	if (ret)
	379	goto out_unlock;
	380
	381	ret = cpuidle_add_sysfs(dev);
	382	if (ret)
	383	goto out_unregister;
dcb84f33	384
10b9d3f8	385	ret = cpuidle_enable_device(dev);
f6bb51a5 DL	386	if (ret)
f6bb51a5 DL	387	goto out_sysfs;
10b9d3f8	388
4f86d3a8 LB	389	cpuidle_install_idle_handler();
4f86d3a8 LB	390
f6bb51a5	391	out_unlock:
4f86d3a8 LB	392	mutex_unlock(&cpuidle_lock);
4f86d3a8 LB	393
f6bb51a5 DL	394	return ret;
	395
	396	out_sysfs:
	397	cpuidle_remove_sysfs(dev);
	398	out_unregister:
	399	__cpuidle_unregister_device(dev);
	400	goto out_unlock;
4f86d3a8 LB	401	}
	402
	403	EXPORT_SYMBOL_GPL(cpuidle_register_device);
	404
	405	/**
	406	* cpuidle_unregister_device - unregisters a CPU's idle PM feature
	407	* @dev: the cpu
	408	*/
	409	void cpuidle_unregister_device(struct cpuidle_device *dev)
	410	{
813e8e3d	411	if (!dev \|\| dev->registered == 0)
dcb84f33 VP	412	return;
dcb84f33 VP	413
4f86d3a8 LB	414	cpuidle_pause_and_lock();
	415
	416	cpuidle_disable_device(dev);
	417
1aef40e2	418	cpuidle_remove_sysfs(dev);
f6bb51a5 DL	419
f6bb51a5 DL	420	__cpuidle_unregister_device(dev);
4f86d3a8	421
4126c019 CC	422	cpuidle_coupled_unregister_device(dev);
4126c019 CC	423
4f86d3a8	424	cpuidle_resume_and_unlock();
4f86d3a8 LB	425	}
	426
	427	EXPORT_SYMBOL_GPL(cpuidle_unregister_device);
	428
1c192d04	429	/**
4c637b21 DL	430	* cpuidle_unregister: unregister a driver and the devices. This function
	431	* can be used only if the driver has been previously registered through
	432	* the cpuidle_register function.
	433	*
	434	* @drv: a valid pointer to a struct cpuidle_driver
	435	*/
	436	void cpuidle_unregister(struct cpuidle_driver *drv)
	437	{
	438	int cpu;
	439	struct cpuidle_device *device;
	440
82467a5a	441	for_each_cpu(cpu, drv->cpumask) {
4c637b21 DL	442	device = &per_cpu(cpuidle_dev, cpu);
	443	cpuidle_unregister_device(device);
	444	}
	445
	446	cpuidle_unregister_driver(drv);
	447	}
	448	EXPORT_SYMBOL_GPL(cpuidle_unregister);
	449
	450	/**
	451	* cpuidle_register: registers the driver and the cpu devices with the
	452	* coupled_cpus passed as parameter. This function is used for all common
	453	* initialization pattern there are in the arch specific drivers. The
	454	* devices is globally defined in this file.
	455	*
	456	* @drv : a valid pointer to a struct cpuidle_driver
	457	* @coupled_cpus: a cpumask for the coupled states
	458	*
	459	* Returns 0 on success, < 0 otherwise
	460	*/
	461	int cpuidle_register(struct cpuidle_driver *drv,
	462	const struct cpumask *const coupled_cpus)
	463	{
	464	int ret, cpu;
	465	struct cpuidle_device *device;
	466
	467	ret = cpuidle_register_driver(drv);
	468	if (ret) {
	469	pr_err("failed to register cpuidle driver\n");
	470	return ret;
	471	}
	472
82467a5a	473	for_each_cpu(cpu, drv->cpumask) {
4c637b21 DL	474	device = &per_cpu(cpuidle_dev, cpu);
	475	device->cpu = cpu;
	476
	477	#ifdef CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED
	478	/*
caf4a36e	479	* On multiplatform for ARM, the coupled idle states could be
4c637b21 DL	480	* enabled in the kernel even if the cpuidle driver does not
	481	* use it. Note, coupled_cpus is a struct copy.
	482	*/
	483	if (coupled_cpus)
	484	device->coupled_cpus = *coupled_cpus;
	485	#endif
	486	ret = cpuidle_register_device(device);
	487	if (!ret)
	488	continue;
	489
	490	pr_err("Failed to register cpuidle device for cpu%d\n", cpu);
	491
	492	cpuidle_unregister(drv);
	493	break;
	494	}
	495
	496	return ret;
	497	}
	498	EXPORT_SYMBOL_GPL(cpuidle_register);
	499
4f86d3a8 LB	500	#ifdef CONFIG_SMP
	501
	502	static void smp_callback(void *v)
	503	{
	504	/* we already woke the CPU up, nothing more to do */
	505	}
	506
	507	/*
	508	* This function gets called when a part of the kernel has a new latency
	509	* requirement. This means we need to get all processors out of their C-state,
	510	* and then recalculate a new suitable C-state. Just do a cross-cpu IPI; that
	511	* wakes them all right up.
	512	*/
	513	static int cpuidle_latency_notify(struct notifier_block *b,
	514	unsigned long l, void *v)
	515	{
8691e5a8	516	smp_call_function(smp_callback, NULL, 1);
4f86d3a8 LB	517	return NOTIFY_OK;
	518	}
	519
	520	static struct notifier_block cpuidle_latency_notifier = {
	521	.notifier_call = cpuidle_latency_notify,
	522	};
	523
d82b3518 MG	524	static inline void latency_notifier_init(struct notifier_block *n)
	525	{
	526	pm_qos_add_notifier(PM_QOS_CPU_DMA_LATENCY, n);
	527	}
4f86d3a8 LB	528
	529	#else /* CONFIG_SMP */
	530
	531	#define latency_notifier_init(x) do { } while (0)
	532
	533	#endif /* CONFIG_SMP */
	534
	535	/**
	536	* cpuidle_init - core initializer
	537	*/
	538	static int __init cpuidle_init(void)
	539	{
	540	int ret;
	541
62027aea LB	542	if (cpuidle_disabled())
	543	return -ENODEV;
	544
8a25a2fd	545	ret = cpuidle_add_interface(cpu_subsys.dev_root);
4f86d3a8 LB	546	if (ret)
	547	return ret;
	548
	549	latency_notifier_init(&cpuidle_latency_notifier);
	550
	551	return 0;
	552	}
	553
62027aea	554	module_param(off, int, 0444);
4f86d3a8	555	core_initcall(cpuidle_init);