[mirror_ubuntu-zesty-kernel.git] / kernel / time / clockevents.c

/*
 * linux/kernel/time/clockevents.c
 *
 * This file contains functions which manage clock event devices.
 *
 * Copyright(C) 2005-2006, Thomas Gleixner <tglx@linutronix.de>
 * Copyright(C) 2005-2007, Red Hat, Inc., Ingo Molnar
 * Copyright(C) 2006-2007, Timesys Corp., Thomas Gleixner
 *
 * This code is licenced under the GPL version 2. For details see
 * kernel-base/COPYING.
 */

#include <linux/clockchips.h>
#include <linux/hrtimer.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/notifier.h>
#include <linux/smp.h>

#include "tick-internal.h"

/* The registered clock event devices */
static LIST_HEAD(clockevent_devices);
static LIST_HEAD(clockevents_released);

/* Notification for clock events */
static RAW_NOTIFIER_HEAD(clockevents_chain);

/* Protection for the above */
static DEFINE_RAW_SPINLOCK(clockevents_lock);

/**
 * clockevents_delta2ns - Convert a latch value (device ticks) to nanoseconds
 * @latch:	value to convert
 * @evt:	pointer to clock event device descriptor
 *
 * Math helper, returns latch value converted to nanoseconds (bound checked)
 */
u64 clockevent_delta2ns(unsigned long latch, struct clock_event_device *evt)
{
	u64 clc = (u64) latch << evt->shift;

	if (unlikely(!evt->mult)) {
		evt->mult = 1;
		WARN_ON(1);
	}

	do_div(clc, evt->mult);
	if (clc < 1000)
		clc = 1000;
	if (clc > KTIME_MAX)
		clc = KTIME_MAX;

	return clc;
}
EXPORT_SYMBOL_GPL(clockevent_delta2ns);

/**
 * clockevents_set_mode - set the operating mode of a clock event device
 * @dev:	device to modify
 * @mode:	new mode
 *
 * Must be called with interrupts disabled !
 */
void clockevents_set_mode(struct clock_event_device *dev,
				 enum clock_event_mode mode)
{
	if (dev->mode != mode) {
		dev->set_mode(mode, dev);
		dev->mode = mode;

		/*
		 * A nsec2cyc multiplicator of 0 is invalid and we'd crash
		 * on it, so fix it up and emit a warning:
		 */
		if (mode == CLOCK_EVT_MODE_ONESHOT) {
			if (unlikely(!dev->mult)) {
				dev->mult = 1;
				WARN_ON(1);
			}
		}
	}
}

/**
 * clockevents_shutdown - shutdown the device and clear next_event
 * @dev:	device to shutdown
 */
void clockevents_shutdown(struct clock_event_device *dev)
{
	clockevents_set_mode(dev, CLOCK_EVT_MODE_SHUTDOWN);
	dev->next_event.tv64 = KTIME_MAX;
}

#ifdef CONFIG_GENERIC_CLOCKEVENTS_MIN_ADJUST

/* Limit min_delta to a jiffie */
#define MIN_DELTA_LIMIT		(NSEC_PER_SEC / HZ)

/**
 * clockevents_increase_min_delta - raise minimum delta of a clock event device
 * @dev:       device to increase the minimum delta
 *
 * Returns 0 on success, -ETIME when the minimum delta reached the limit.
 */
static int clockevents_increase_min_delta(struct clock_event_device *dev)
{
	/* Nothing to do if we already reached the limit */
	if (dev->min_delta_ns >= MIN_DELTA_LIMIT) {
		printk(KERN_WARNING "CE: Reprogramming failure. Giving up\n");
		dev->next_event.tv64 = KTIME_MAX;
		return -ETIME;
	}

	if (dev->min_delta_ns < 5000)
		dev->min_delta_ns = 5000;
	else
		dev->min_delta_ns += dev->min_delta_ns >> 1;

	if (dev->min_delta_ns > MIN_DELTA_LIMIT)
		dev->min_delta_ns = MIN_DELTA_LIMIT;

	printk(KERN_WARNING "CE: %s increased min_delta_ns to %llu nsec\n",
	       dev->name ? dev->name : "?",
	       (unsigned long long) dev->min_delta_ns);
	return 0;
}

/**
 * clockevents_program_min_delta - Set clock event device to the minimum delay.
 * @dev:	device to program
 *
 * Returns 0 on success, -ETIME when the retry loop failed.
 */
static int clockevents_program_min_delta(struct clock_event_device *dev)
{
	unsigned long long clc;
	int64_t delta;
	int i;

	for (i = 0;;) {
		delta = dev->min_delta_ns;
		dev->next_event = ktime_add_ns(ktime_get(), delta);

		if (dev->mode == CLOCK_EVT_MODE_SHUTDOWN)
			return 0;

		dev->retries++;
		clc = ((unsigned long long) delta * dev->mult) >> dev->shift;
		if (dev->set_next_event((unsigned long) clc, dev) == 0)
			return 0;

		if (++i > 2) {
			/*
			 * We tried 3 times to program the device with the
			 * given min_delta_ns. Try to increase the minimum
			 * delta, if that fails as well get out of here.
			 */
			if (clockevents_increase_min_delta(dev))
				return -ETIME;
			i = 0;
		}
	}
}

#else  /* CONFIG_GENERIC_CLOCKEVENTS_MIN_ADJUST */

/**
 * clockevents_program_min_delta - Set clock event device to the minimum delay.
 * @dev:	device to program
 *
 * Returns 0 on success, -ETIME when the retry loop failed.
 */
static int clockevents_program_min_delta(struct clock_event_device *dev)
{
	unsigned long long clc;
	int64_t delta;

	delta = dev->min_delta_ns;
	dev->next_event = ktime_add_ns(ktime_get(), delta);

	if (dev->mode == CLOCK_EVT_MODE_SHUTDOWN)
		return 0;

	dev->retries++;
	clc = ((unsigned long long) delta * dev->mult) >> dev->shift;
	return dev->set_next_event((unsigned long) clc, dev);
}

#endif /* CONFIG_GENERIC_CLOCKEVENTS_MIN_ADJUST */

/**
 * clockevents_program_event - Reprogram the clock event device.
 * @dev:	device to program
 * @expires:	absolute expiry time (monotonic clock)
 * @force:	program minimum delay if expires can not be set
 *
 * Returns 0 on success, -ETIME when the event is in the past.
 */
int clockevents_program_event(struct clock_event_device *dev, ktime_t expires,
			      bool force)
{
	unsigned long long clc;
	int64_t delta;
	int rc;

	if (unlikely(expires.tv64 < 0)) {
		WARN_ON_ONCE(1);
		return -ETIME;
	}

	dev->next_event = expires;

	if (dev->mode == CLOCK_EVT_MODE_SHUTDOWN)
		return 0;

	/* Shortcut for clockevent devices that can deal with ktime. */
	if (dev->features & CLOCK_EVT_FEAT_KTIME)
		return dev->set_next_ktime(expires, dev);

	delta = ktime_to_ns(ktime_sub(expires, ktime_get()));
	if (delta <= 0)
		return force ? clockevents_program_min_delta(dev) : -ETIME;

	delta = min(delta, (int64_t) dev->max_delta_ns);
	delta = max(delta, (int64_t) dev->min_delta_ns);

	clc = ((unsigned long long) delta * dev->mult) >> dev->shift;
	rc = dev->set_next_event((unsigned long) clc, dev);

	return (rc && force) ? clockevents_program_min_delta(dev) : rc;
}

/**
 * clockevents_register_notifier - register a clock events change listener
 */
int clockevents_register_notifier(struct notifier_block *nb)
{
	unsigned long flags;
	int ret;

	raw_spin_lock_irqsave(&clockevents_lock, flags);
	ret = raw_notifier_chain_register(&clockevents_chain, nb);
	raw_spin_unlock_irqrestore(&clockevents_lock, flags);

	return ret;
}

/*
 * Notify about a clock event change. Called with clockevents_lock
 * held.
 */
static void clockevents_do_notify(unsigned long reason, void *dev)
{
	raw_notifier_call_chain(&clockevents_chain, reason, dev);
}

/*
 * Called after a notify add to make devices available which were
 * released from the notifier call.
 */
static void clockevents_notify_released(void)
{
	struct clock_event_device *dev;

	while (!list_empty(&clockevents_released)) {
		dev = list_entry(clockevents_released.next,
				 struct clock_event_device, list);
		list_del(&dev->list);
		list_add(&dev->list, &clockevent_devices);
		clockevents_do_notify(CLOCK_EVT_NOTIFY_ADD, dev);
	}
}

/**
 * clockevents_register_device - register a clock event device
 * @dev:	device to register
 */
void clockevents_register_device(struct clock_event_device *dev)
{
	unsigned long flags;

	BUG_ON(dev->mode != CLOCK_EVT_MODE_UNUSED);
	if (!dev->cpumask) {
		WARN_ON(num_possible_cpus() > 1);
		dev->cpumask = cpumask_of(smp_processor_id());
	}

	raw_spin_lock_irqsave(&clockevents_lock, flags);

	list_add(&dev->list, &clockevent_devices);
	clockevents_do_notify(CLOCK_EVT_NOTIFY_ADD, dev);
	clockevents_notify_released();

	raw_spin_unlock_irqrestore(&clockevents_lock, flags);
}
EXPORT_SYMBOL_GPL(clockevents_register_device);

static void clockevents_config(struct clock_event_device *dev,
			       u32 freq)
{
	u64 sec;

	if (!(dev->features & CLOCK_EVT_FEAT_ONESHOT))
		return;

	/*
	 * Calculate the maximum number of seconds we can sleep. Limit
	 * to 10 minutes for hardware which can program more than
	 * 32bit ticks so we still get reasonable conversion values.
	 */
	sec = dev->max_delta_ticks;
	do_div(sec, freq);
	if (!sec)
		sec = 1;
	else if (sec > 600 && dev->max_delta_ticks > UINT_MAX)
		sec = 600;

	clockevents_calc_mult_shift(dev, freq, sec);
	dev->min_delta_ns = clockevent_delta2ns(dev->min_delta_ticks, dev);
	dev->max_delta_ns = clockevent_delta2ns(dev->max_delta_ticks, dev);
}

/**
 * clockevents_config_and_register - Configure and register a clock event device
 * @dev:	device to register
 * @freq:	The clock frequency
 * @min_delta:	The minimum clock ticks to program in oneshot mode
 * @max_delta:	The maximum clock ticks to program in oneshot mode
 *
 * min/max_delta can be 0 for devices which do not support oneshot mode.
 */
void clockevents_config_and_register(struct clock_event_device *dev,
				     u32 freq, unsigned long min_delta,
				     unsigned long max_delta)
{
	dev->min_delta_ticks = min_delta;
	dev->max_delta_ticks = max_delta;
	clockevents_config(dev, freq);
	clockevents_register_device(dev);
}

/**
 * clockevents_update_freq - Update frequency and reprogram a clock event device.
 * @dev:	device to modify
 * @freq:	new device frequency
 *
 * Reconfigure and reprogram a clock event device in oneshot
 * mode. Must be called on the cpu for which the device delivers per
 * cpu timer events with interrupts disabled!  Returns 0 on success,
 * -ETIME when the event is in the past.
 */
int clockevents_update_freq(struct clock_event_device *dev, u32 freq)
{
	clockevents_config(dev, freq);

	if (dev->mode != CLOCK_EVT_MODE_ONESHOT)
		return 0;

	return clockevents_program_event(dev, dev->next_event, false);
}

/*
 * Noop handler when we shut down an event device
 */
void clockevents_handle_noop(struct clock_event_device *dev)
{
}

/**
 * clockevents_exchange_device - release and request clock devices
 * @old:	device to release (can be NULL)
 * @new:	device to request (can be NULL)
 *
 * Called from the notifier chain. clockevents_lock is held already
 */
void clockevents_exchange_device(struct clock_event_device *old,
				 struct clock_event_device *new)
{
	unsigned long flags;

	local_irq_save(flags);
	/*
	 * Caller releases a clock event device. We queue it into the
	 * released list and do a notify add later.
	 */
	if (old) {
		clockevents_set_mode(old, CLOCK_EVT_MODE_UNUSED);
		list_del(&old->list);
		list_add(&old->list, &clockevents_released);
	}

	if (new) {
		BUG_ON(new->mode != CLOCK_EVT_MODE_UNUSED);
		clockevents_shutdown(new);
	}
	local_irq_restore(flags);
}

#ifdef CONFIG_GENERIC_CLOCKEVENTS
/**
 * clockevents_notify - notification about relevant events
 */
void clockevents_notify(unsigned long reason, void *arg)
{
	struct clock_event_device *dev, *tmp;
	unsigned long flags;
	int cpu;

	raw_spin_lock_irqsave(&clockevents_lock, flags);
	clockevents_do_notify(reason, arg);

	switch (reason) {
	case CLOCK_EVT_NOTIFY_CPU_DEAD:
		/*
		 * Unregister the clock event devices which were
		 * released from the users in the notify chain.
		 */
		list_for_each_entry_safe(dev, tmp, &clockevents_released, list)
			list_del(&dev->list);
		/*
		 * Now check whether the CPU has left unused per cpu devices
		 */
		cpu = *((int *)arg);
		list_for_each_entry_safe(dev, tmp, &clockevent_devices, list) {
			if (cpumask_test_cpu(cpu, dev->cpumask) &&
			    cpumask_weight(dev->cpumask) == 1 &&
			    !tick_is_broadcast_device(dev)) {
				BUG_ON(dev->mode != CLOCK_EVT_MODE_UNUSED);
				list_del(&dev->list);
			}
		}
		break;
	default:
		break;
	}
	raw_spin_unlock_irqrestore(&clockevents_lock, flags);
}
EXPORT_SYMBOL_GPL(clockevents_notify);
#endif
Commit	Line	Data
d316c57f TG	1	/*
	2	* linux/kernel/time/clockevents.c
	3	*
	4	* This file contains functions which manage clock event devices.
	5	*
	6	* Copyright(C) 2005-2006, Thomas Gleixner <tglx@linutronix.de>
	7	* Copyright(C) 2005-2007, Red Hat, Inc., Ingo Molnar
	8	* Copyright(C) 2006-2007, Timesys Corp., Thomas Gleixner
	9	*
	10	* This code is licenced under the GPL version 2. For details see
	11	* kernel-base/COPYING.
	12	*/
	13
	14	#include <linux/clockchips.h>
	15	#include <linux/hrtimer.h>
	16	#include <linux/init.h>
	17	#include <linux/module.h>
	18	#include <linux/notifier.h>
	19	#include <linux/smp.h>
d316c57f	20
8e1a928a HS	21	#include "tick-internal.h"
8e1a928a HS	22
d316c57f TG	23	/* The registered clock event devices */
	24	static LIST_HEAD(clockevent_devices);
	25	static LIST_HEAD(clockevents_released);
	26
	27	/* Notification for clock events */
	28	static RAW_NOTIFIER_HEAD(clockevents_chain);
	29
	30	/* Protection for the above */
b5f91da0	31	static DEFINE_RAW_SPINLOCK(clockevents_lock);
d316c57f TG	32
	33	/**
	34	* clockevents_delta2ns - Convert a latch value (device ticks) to nanoseconds
	35	* @latch: value to convert
	36	* @evt: pointer to clock event device descriptor
	37	*
	38	* Math helper, returns latch value converted to nanoseconds (bound checked)
	39	*/
97813f2f	40	u64 clockevent_delta2ns(unsigned long latch, struct clock_event_device *evt)
d316c57f	41	{
97813f2f	42	u64 clc = (u64) latch << evt->shift;
d316c57f	43
45fe4fe1 IM	44	if (unlikely(!evt->mult)) {
	45	evt->mult = 1;
	46	WARN_ON(1);
	47	}
	48
d316c57f TG	49	do_div(clc, evt->mult);
	50	if (clc < 1000)
	51	clc = 1000;
97813f2f JH	52	if (clc > KTIME_MAX)
97813f2f JH	53	clc = KTIME_MAX;
d316c57f	54
97813f2f	55	return clc;
d316c57f	56	}
c81fc2c3	57	EXPORT_SYMBOL_GPL(clockevent_delta2ns);
d316c57f TG	58
	59	/**
	60	* clockevents_set_mode - set the operating mode of a clock event device
	61	* @dev: device to modify
	62	* @mode: new mode
	63	*
	64	* Must be called with interrupts disabled !
	65	*/
	66	void clockevents_set_mode(struct clock_event_device *dev,
	67	enum clock_event_mode mode)
	68	{
	69	if (dev->mode != mode) {
	70	dev->set_mode(mode, dev);
	71	dev->mode = mode;
2d68259d MD	72
	73	/*
	74	* A nsec2cyc multiplicator of 0 is invalid and we'd crash
	75	* on it, so fix it up and emit a warning:
	76	*/
	77	if (mode == CLOCK_EVT_MODE_ONESHOT) {
	78	if (unlikely(!dev->mult)) {
	79	dev->mult = 1;
	80	WARN_ON(1);
	81	}
	82	}
d316c57f TG	83	}
	84	}
	85
2344abbc TG	86	/**
	87	* clockevents_shutdown - shutdown the device and clear next_event
	88	* @dev: device to shutdown
	89	*/
	90	void clockevents_shutdown(struct clock_event_device *dev)
	91	{
	92	clockevents_set_mode(dev, CLOCK_EVT_MODE_SHUTDOWN);
	93	dev->next_event.tv64 = KTIME_MAX;
	94	}
	95
d1748302 MS	96	#ifdef CONFIG_GENERIC_CLOCKEVENTS_MIN_ADJUST
	97
	98	/* Limit min_delta to a jiffie */
	99	#define MIN_DELTA_LIMIT (NSEC_PER_SEC / HZ)
	100
	101	/**
	102	* clockevents_increase_min_delta - raise minimum delta of a clock event device
	103	* @dev: device to increase the minimum delta
	104	*
	105	* Returns 0 on success, -ETIME when the minimum delta reached the limit.
	106	*/
	107	static int clockevents_increase_min_delta(struct clock_event_device *dev)
	108	{
	109	/* Nothing to do if we already reached the limit */
	110	if (dev->min_delta_ns >= MIN_DELTA_LIMIT) {
	111	printk(KERN_WARNING "CE: Reprogramming failure. Giving up\n");
	112	dev->next_event.tv64 = KTIME_MAX;
	113	return -ETIME;
	114	}
	115
	116	if (dev->min_delta_ns < 5000)
	117	dev->min_delta_ns = 5000;
	118	else
	119	dev->min_delta_ns += dev->min_delta_ns >> 1;
	120
	121	if (dev->min_delta_ns > MIN_DELTA_LIMIT)
	122	dev->min_delta_ns = MIN_DELTA_LIMIT;
	123
	124	printk(KERN_WARNING "CE: %s increased min_delta_ns to %llu nsec\n",
	125	dev->name ? dev->name : "?",
	126	(unsigned long long) dev->min_delta_ns);
	127	return 0;
	128	}
	129
	130	/**
	131	* clockevents_program_min_delta - Set clock event device to the minimum delay.
	132	* @dev: device to program
	133	*
	134	* Returns 0 on success, -ETIME when the retry loop failed.
	135	*/
	136	static int clockevents_program_min_delta(struct clock_event_device *dev)
	137	{
	138	unsigned long long clc;
	139	int64_t delta;
	140	int i;
	141
	142	for (i = 0;;) {
	143	delta = dev->min_delta_ns;
	144	dev->next_event = ktime_add_ns(ktime_get(), delta);
	145
	146	if (dev->mode == CLOCK_EVT_MODE_SHUTDOWN)
	147	return 0;
	148
	149	dev->retries++;
	150	clc = ((unsigned long long) delta * dev->mult) >> dev->shift;
	151	if (dev->set_next_event((unsigned long) clc, dev) == 0)
	152	return 0;
	153
	154	if (++i > 2) {
	155	/*
	156	* We tried 3 times to program the device with the
	157	* given min_delta_ns. Try to increase the minimum
	158	* delta, if that fails as well get out of here.
	159	*/
160	if (clockevents_increase_min_delta(dev))
161	return -ETIME;
162	i = 0;
163	}
164	}
165	}
166
167	#else /* CONFIG_GENERIC_CLOCKEVENTS_MIN_ADJUST */
168
169	/**
170	* clockevents_program_min_delta - Set clock event device to the minimum delay.
171	* @dev: device to program
172	*
173	* Returns 0 on success, -ETIME when the retry loop failed.
174	*/
175	static int clockevents_program_min_delta(struct clock_event_device *dev)
176	{
177	unsigned long long clc;
178	int64_t delta;
179
180	delta = dev->min_delta_ns;
181	dev->next_event = ktime_add_ns(ktime_get(), delta);
182
183	if (dev->mode == CLOCK_EVT_MODE_SHUTDOWN)
184	return 0;
185
186	dev->retries++;
187	clc = ((unsigned long long) delta * dev->mult) >> dev->shift;
188	return dev->set_next_event((unsigned long) clc, dev);
189	}
190
191	#endif /* CONFIG_GENERIC_CLOCKEVENTS_MIN_ADJUST */
192
d316c57f TG	193	/**
d316c57f TG	194	* clockevents_program_event - Reprogram the clock event device.
d1748302	195	* @dev: device to program
d316c57f	196	* @expires: absolute expiry time (monotonic clock)
d1748302	197	* @force: program minimum delay if expires can not be set
d316c57f TG	198	*
	199	* Returns 0 on success, -ETIME when the event is in the past.
	200	*/
	201	int clockevents_program_event(struct clock_event_device *dev, ktime_t expires,
d1748302	202	bool force)
d316c57f TG	203	{
	204	unsigned long long clc;
	205	int64_t delta;
d1748302	206	int rc;
d316c57f	207
167b1de3 TG	208	if (unlikely(expires.tv64 < 0)) {
	209	WARN_ON_ONCE(1);
	210	return -ETIME;
	211	}
	212
d316c57f TG	213	dev->next_event = expires;
	214
	215	if (dev->mode == CLOCK_EVT_MODE_SHUTDOWN)
	216	return 0;
	217
65516f8a MS	218	/* Shortcut for clockevent devices that can deal with ktime. */
	219	if (dev->features & CLOCK_EVT_FEAT_KTIME)
	220	return dev->set_next_ktime(expires, dev);
	221
d1748302 MS	222	delta = ktime_to_ns(ktime_sub(expires, ktime_get()));
	223	if (delta <= 0)
	224	return force ? clockevents_program_min_delta(dev) : -ETIME;
d316c57f	225
d1748302 MS	226	delta = min(delta, (int64_t) dev->max_delta_ns);
d1748302 MS	227	delta = max(delta, (int64_t) dev->min_delta_ns);
d316c57f	228
d1748302 MS	229	clc = ((unsigned long long) delta * dev->mult) >> dev->shift;
	230	rc = dev->set_next_event((unsigned long) clc, dev);
	231
	232	return (rc && force) ? clockevents_program_min_delta(dev) : rc;
d316c57f TG	233	}
	234
	235	/**
	236	* clockevents_register_notifier - register a clock events change listener
	237	*/
	238	int clockevents_register_notifier(struct notifier_block *nb)
	239	{
f833bab8	240	unsigned long flags;
d316c57f TG	241	int ret;
d316c57f TG	242
b5f91da0	243	raw_spin_lock_irqsave(&clockevents_lock, flags);
d316c57f	244	ret = raw_notifier_chain_register(&clockevents_chain, nb);
b5f91da0	245	raw_spin_unlock_irqrestore(&clockevents_lock, flags);
d316c57f TG	246
	247	return ret;
	248	}
	249
d316c57f TG	250	/*
	251	* Notify about a clock event change. Called with clockevents_lock
	252	* held.
	253	*/
	254	static void clockevents_do_notify(unsigned long reason, void *dev)
	255	{
	256	raw_notifier_call_chain(&clockevents_chain, reason, dev);
	257	}
	258
	259	/*
3eb05676	260	* Called after a notify add to make devices available which were
d316c57f TG	261	* released from the notifier call.
	262	*/
	263	static void clockevents_notify_released(void)
	264	{
	265	struct clock_event_device *dev;
	266
	267	while (!list_empty(&clockevents_released)) {
	268	dev = list_entry(clockevents_released.next,
	269	struct clock_event_device, list);
	270	list_del(&dev->list);
	271	list_add(&dev->list, &clockevent_devices);
	272	clockevents_do_notify(CLOCK_EVT_NOTIFY_ADD, dev);
	273	}
	274	}
	275
	276	/**
	277	* clockevents_register_device - register a clock event device
	278	* @dev: device to register
	279	*/
	280	void clockevents_register_device(struct clock_event_device *dev)
	281	{
f833bab8 SS	282	unsigned long flags;
f833bab8 SS	283
d316c57f	284	BUG_ON(dev->mode != CLOCK_EVT_MODE_UNUSED);
1b054b67 TG	285	if (!dev->cpumask) {
	286	WARN_ON(num_possible_cpus() > 1);
	287	dev->cpumask = cpumask_of(smp_processor_id());
	288	}
320ab2b0	289
b5f91da0	290	raw_spin_lock_irqsave(&clockevents_lock, flags);
d316c57f TG	291
	292	list_add(&dev->list, &clockevent_devices);
	293	clockevents_do_notify(CLOCK_EVT_NOTIFY_ADD, dev);
	294	clockevents_notify_released();
	295
b5f91da0	296	raw_spin_unlock_irqrestore(&clockevents_lock, flags);
d316c57f	297	}
c81fc2c3	298	EXPORT_SYMBOL_GPL(clockevents_register_device);
d316c57f	299
57f0fcbe TG	300	static void clockevents_config(struct clock_event_device *dev,
	301	u32 freq)
	302	{
c0e299b1	303	u64 sec;
57f0fcbe TG	304
	305	if (!(dev->features & CLOCK_EVT_FEAT_ONESHOT))
	306	return;
	307
	308	/*
	309	* Calculate the maximum number of seconds we can sleep. Limit
	310	* to 10 minutes for hardware which can program more than
	311	* 32bit ticks so we still get reasonable conversion values.
	312	*/
	313	sec = dev->max_delta_ticks;
	314	do_div(sec, freq);
	315	if (!sec)
	316	sec = 1;
	317	else if (sec > 600 && dev->max_delta_ticks > UINT_MAX)
	318	sec = 600;
	319
	320	clockevents_calc_mult_shift(dev, freq, sec);
	321	dev->min_delta_ns = clockevent_delta2ns(dev->min_delta_ticks, dev);
	322	dev->max_delta_ns = clockevent_delta2ns(dev->max_delta_ticks, dev);
	323	}
	324
	325	/**
	326	* clockevents_config_and_register - Configure and register a clock event device
	327	* @dev: device to register
	328	* @freq: The clock frequency
	329	* @min_delta: The minimum clock ticks to program in oneshot mode
	330	* @max_delta: The maximum clock ticks to program in oneshot mode
	331	*
	332	* min/max_delta can be 0 for devices which do not support oneshot mode.
	333	*/
	334	void clockevents_config_and_register(struct clock_event_device *dev,
	335	u32 freq, unsigned long min_delta,
	336	unsigned long max_delta)
	337	{
	338	dev->min_delta_ticks = min_delta;
	339	dev->max_delta_ticks = max_delta;
	340	clockevents_config(dev, freq);
	341	clockevents_register_device(dev);
	342	}
	343
80b816b7 TG	344	/**
	345	* clockevents_update_freq - Update frequency and reprogram a clock event device.
	346	* @dev: device to modify
	347	* @freq: new device frequency
	348	*
	349	* Reconfigure and reprogram a clock event device in oneshot
	350	* mode. Must be called on the cpu for which the device delivers per
	351	* cpu timer events with interrupts disabled! Returns 0 on success,
	352	* -ETIME when the event is in the past.
	353	*/
	354	int clockevents_update_freq(struct clock_event_device *dev, u32 freq)
	355	{
	356	clockevents_config(dev, freq);
	357
	358	if (dev->mode != CLOCK_EVT_MODE_ONESHOT)
	359	return 0;
	360
d1748302	361	return clockevents_program_event(dev, dev->next_event, false);
80b816b7 TG	362	}
80b816b7 TG	363
d316c57f TG	364	/*
	365	* Noop handler when we shut down an event device
	366	*/
7c1e7689	367	void clockevents_handle_noop(struct clock_event_device *dev)
d316c57f TG	368	{
	369	}
	370
	371	/**
	372	* clockevents_exchange_device - release and request clock devices
	373	* @old: device to release (can be NULL)
	374	* @new: device to request (can be NULL)
	375	*
	376	* Called from the notifier chain. clockevents_lock is held already
	377	*/
	378	void clockevents_exchange_device(struct clock_event_device *old,
	379	struct clock_event_device *new)
	380	{
	381	unsigned long flags;
	382
	383	local_irq_save(flags);
	384	/*
	385	* Caller releases a clock event device. We queue it into the
	386	* released list and do a notify add later.
	387	*/
	388	if (old) {
d316c57f TG	389	clockevents_set_mode(old, CLOCK_EVT_MODE_UNUSED);
	390	list_del(&old->list);
	391	list_add(&old->list, &clockevents_released);
	392	}
	393
	394	if (new) {
	395	BUG_ON(new->mode != CLOCK_EVT_MODE_UNUSED);
2344abbc	396	clockevents_shutdown(new);
d316c57f TG	397	}
	398	local_irq_restore(flags);
	399	}
	400
de68d9b1	401	#ifdef CONFIG_GENERIC_CLOCKEVENTS
d316c57f TG	402	/**
	403	* clockevents_notify - notification about relevant events
	404	*/
	405	void clockevents_notify(unsigned long reason, void *arg)
	406	{
bb6eddf7	407	struct clock_event_device dev, tmp;
f833bab8	408	unsigned long flags;
bb6eddf7	409	int cpu;
0b858e6f	410
b5f91da0	411	raw_spin_lock_irqsave(&clockevents_lock, flags);
d316c57f TG	412	clockevents_do_notify(reason, arg);
	413
	414	switch (reason) {
	415	case CLOCK_EVT_NOTIFY_CPU_DEAD:
	416	/*
	417	* Unregister the clock event devices which were
	418	* released from the users in the notify chain.
	419	*/
bb6eddf7 TG	420	list_for_each_entry_safe(dev, tmp, &clockevents_released, list)
	421	list_del(&dev->list);
	422	/*
	423	* Now check whether the CPU has left unused per cpu devices
	424	*/
	425	cpu = ((int )arg);
	426	list_for_each_entry_safe(dev, tmp, &clockevent_devices, list) {
	427	if (cpumask_test_cpu(cpu, dev->cpumask) &&
ea9d8e3f XF	428	cpumask_weight(dev->cpumask) == 1 &&
ea9d8e3f XF	429	!tick_is_broadcast_device(dev)) {
bb6eddf7 TG	430	BUG_ON(dev->mode != CLOCK_EVT_MODE_UNUSED);
	431	list_del(&dev->list);
	432	}
	433	}
d316c57f TG	434	break;
	435	default:
	436	break;
	437	}
b5f91da0	438	raw_spin_unlock_irqrestore(&clockevents_lock, flags);
d316c57f TG	439	}
d316c57f TG	440	EXPORT_SYMBOL_GPL(clockevents_notify);
de68d9b1	441	#endif