[deliverable/linux.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 <linux/sysdev.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>
	20	#include <linux/sysdev.h>
	21
8e1a928a HS	22	#include "tick-internal.h"
8e1a928a HS	23
d316c57f TG	24	/* The registered clock event devices */
	25	static LIST_HEAD(clockevent_devices);
	26	static LIST_HEAD(clockevents_released);
	27
	28	/* Notification for clock events */
	29	static RAW_NOTIFIER_HEAD(clockevents_chain);
	30
	31	/* Protection for the above */
b5f91da0	32	static DEFINE_RAW_SPINLOCK(clockevents_lock);
d316c57f TG	33
	34	/**
	35	* clockevents_delta2ns - Convert a latch value (device ticks) to nanoseconds
	36	* @latch: value to convert
	37	* @evt: pointer to clock event device descriptor
	38	*
	39	* Math helper, returns latch value converted to nanoseconds (bound checked)
	40	*/
97813f2f	41	u64 clockevent_delta2ns(unsigned long latch, struct clock_event_device *evt)
d316c57f	42	{
97813f2f	43	u64 clc = (u64) latch << evt->shift;
d316c57f	44
45fe4fe1 IM	45	if (unlikely(!evt->mult)) {
	46	evt->mult = 1;
	47	WARN_ON(1);
	48	}
	49
d316c57f TG	50	do_div(clc, evt->mult);
	51	if (clc < 1000)
	52	clc = 1000;
97813f2f JH	53	if (clc > KTIME_MAX)
97813f2f JH	54	clc = KTIME_MAX;
d316c57f	55
97813f2f	56	return clc;
d316c57f	57	}
c81fc2c3	58	EXPORT_SYMBOL_GPL(clockevent_delta2ns);
d316c57f TG	59
	60	/**
	61	* clockevents_set_mode - set the operating mode of a clock event device
	62	* @dev: device to modify
	63	* @mode: new mode
	64	*
	65	* Must be called with interrupts disabled !
	66	*/
	67	void clockevents_set_mode(struct clock_event_device *dev,
	68	enum clock_event_mode mode)
	69	{
	70	if (dev->mode != mode) {
	71	dev->set_mode(mode, dev);
	72	dev->mode = mode;
2d68259d MD	73
	74	/*
	75	* A nsec2cyc multiplicator of 0 is invalid and we'd crash
	76	* on it, so fix it up and emit a warning:
	77	*/
	78	if (mode == CLOCK_EVT_MODE_ONESHOT) {
	79	if (unlikely(!dev->mult)) {
	80	dev->mult = 1;
	81	WARN_ON(1);
	82	}
	83	}
d316c57f TG	84	}
	85	}
	86
2344abbc TG	87	/**
	88	* clockevents_shutdown - shutdown the device and clear next_event
	89	* @dev: device to shutdown
	90	*/
	91	void clockevents_shutdown(struct clock_event_device *dev)
	92	{
	93	clockevents_set_mode(dev, CLOCK_EVT_MODE_SHUTDOWN);
	94	dev->next_event.tv64 = KTIME_MAX;
	95	}
	96
d1748302 MS	97	#ifdef CONFIG_GENERIC_CLOCKEVENTS_MIN_ADJUST
	98
	99	/* Limit min_delta to a jiffie */
	100	#define MIN_DELTA_LIMIT (NSEC_PER_SEC / HZ)
	101
	102	/**
	103	* clockevents_increase_min_delta - raise minimum delta of a clock event device
	104	* @dev: device to increase the minimum delta
	105	*
	106	* Returns 0 on success, -ETIME when the minimum delta reached the limit.
	107	*/
	108	static int clockevents_increase_min_delta(struct clock_event_device *dev)
	109	{
	110	/* Nothing to do if we already reached the limit */
	111	if (dev->min_delta_ns >= MIN_DELTA_LIMIT) {
	112	printk(KERN_WARNING "CE: Reprogramming failure. Giving up\n");
	113	dev->next_event.tv64 = KTIME_MAX;
	114	return -ETIME;
	115	}
	116
	117	if (dev->min_delta_ns < 5000)
	118	dev->min_delta_ns = 5000;
	119	else
	120	dev->min_delta_ns += dev->min_delta_ns >> 1;
	121
	122	if (dev->min_delta_ns > MIN_DELTA_LIMIT)
	123	dev->min_delta_ns = MIN_DELTA_LIMIT;
	124
	125	printk(KERN_WARNING "CE: %s increased min_delta_ns to %llu nsec\n",
	126	dev->name ? dev->name : "?",
	127	(unsigned long long) dev->min_delta_ns);
	128	return 0;
	129	}
	130
	131	/**
	132	* clockevents_program_min_delta - Set clock event device to the minimum delay.
	133	* @dev: device to program
	134	*
	135	* Returns 0 on success, -ETIME when the retry loop failed.
	136	*/
	137	static int clockevents_program_min_delta(struct clock_event_device *dev)
	138	{
	139	unsigned long long clc;
	140	int64_t delta;
	141	int i;
	142
	143	for (i = 0;;) {
	144	delta = dev->min_delta_ns;
	145	dev->next_event = ktime_add_ns(ktime_get(), delta);
	146
	147	if (dev->mode == CLOCK_EVT_MODE_SHUTDOWN)
	148	return 0;
	149
	150	dev->retries++;
	151	clc = ((unsigned long long) delta * dev->mult) >> dev->shift;
	152	if (dev->set_next_event((unsigned long) clc, dev) == 0)
	153	return 0;
	154
	155	if (++i > 2) {
	156	/*
	157	* We tried 3 times to program the device with the
	158	* given min_delta_ns. Try to increase the minimum
	159	* delta, if that fails as well get out of here.
	160	*/
161	if (clockevents_increase_min_delta(dev))
162	return -ETIME;
163	i = 0;
164	}
165	}
166	}
167
168	#else /* CONFIG_GENERIC_CLOCKEVENTS_MIN_ADJUST */
169
170	/**
171	* clockevents_program_min_delta - Set clock event device to the minimum delay.
172	* @dev: device to program
173	*
174	* Returns 0 on success, -ETIME when the retry loop failed.
175	*/
176	static int clockevents_program_min_delta(struct clock_event_device *dev)
177	{
178	unsigned long long clc;
179	int64_t delta;
180
181	delta = dev->min_delta_ns;
182	dev->next_event = ktime_add_ns(ktime_get(), delta);
183
184	if (dev->mode == CLOCK_EVT_MODE_SHUTDOWN)
185	return 0;
186
187	dev->retries++;
188	clc = ((unsigned long long) delta * dev->mult) >> dev->shift;
189	return dev->set_next_event((unsigned long) clc, dev);
190	}
191
192	#endif /* CONFIG_GENERIC_CLOCKEVENTS_MIN_ADJUST */
193
d316c57f TG	194	/**
d316c57f TG	195	* clockevents_program_event - Reprogram the clock event device.
d1748302	196	* @dev: device to program
d316c57f	197	* @expires: absolute expiry time (monotonic clock)
d1748302	198	* @force: program minimum delay if expires can not be set
d316c57f TG	199	*
	200	* Returns 0 on success, -ETIME when the event is in the past.
	201	*/
	202	int clockevents_program_event(struct clock_event_device *dev, ktime_t expires,
d1748302	203	bool force)
d316c57f TG	204	{
	205	unsigned long long clc;
	206	int64_t delta;
d1748302	207	int rc;
d316c57f	208
167b1de3 TG	209	if (unlikely(expires.tv64 < 0)) {
	210	WARN_ON_ONCE(1);
	211	return -ETIME;
	212	}
	213
d316c57f TG	214	dev->next_event = expires;
	215
	216	if (dev->mode == CLOCK_EVT_MODE_SHUTDOWN)
	217	return 0;
	218
65516f8a MS	219	/* Shortcut for clockevent devices that can deal with ktime. */
	220	if (dev->features & CLOCK_EVT_FEAT_KTIME)
	221	return dev->set_next_ktime(expires, dev);
	222
d1748302 MS	223	delta = ktime_to_ns(ktime_sub(expires, ktime_get()));
	224	if (delta <= 0)
	225	return force ? clockevents_program_min_delta(dev) : -ETIME;
d316c57f	226
d1748302 MS	227	delta = min(delta, (int64_t) dev->max_delta_ns);
d1748302 MS	228	delta = max(delta, (int64_t) dev->min_delta_ns);
d316c57f	229
d1748302 MS	230	clc = ((unsigned long long) delta * dev->mult) >> dev->shift;
	231	rc = dev->set_next_event((unsigned long) clc, dev);
	232
	233	return (rc && force) ? clockevents_program_min_delta(dev) : rc;
d316c57f TG	234	}
	235
	236	/**
	237	* clockevents_register_notifier - register a clock events change listener
	238	*/
	239	int clockevents_register_notifier(struct notifier_block *nb)
	240	{
f833bab8	241	unsigned long flags;
d316c57f TG	242	int ret;
d316c57f TG	243
b5f91da0	244	raw_spin_lock_irqsave(&clockevents_lock, flags);
d316c57f	245	ret = raw_notifier_chain_register(&clockevents_chain, nb);
b5f91da0	246	raw_spin_unlock_irqrestore(&clockevents_lock, flags);
d316c57f TG	247
	248	return ret;
	249	}
	250
d316c57f TG	251	/*
	252	* Notify about a clock event change. Called with clockevents_lock
	253	* held.
	254	*/
	255	static void clockevents_do_notify(unsigned long reason, void *dev)
	256	{
	257	raw_notifier_call_chain(&clockevents_chain, reason, dev);
	258	}
	259
	260	/*
3eb05676	261	* Called after a notify add to make devices available which were
d316c57f TG	262	* released from the notifier call.
	263	*/
	264	static void clockevents_notify_released(void)
	265	{
	266	struct clock_event_device *dev;
	267
	268	while (!list_empty(&clockevents_released)) {
	269	dev = list_entry(clockevents_released.next,
	270	struct clock_event_device, list);
	271	list_del(&dev->list);
	272	list_add(&dev->list, &clockevent_devices);
	273	clockevents_do_notify(CLOCK_EVT_NOTIFY_ADD, dev);
	274	}
	275	}
	276
	277	/**
	278	* clockevents_register_device - register a clock event device
	279	* @dev: device to register
	280	*/
	281	void clockevents_register_device(struct clock_event_device *dev)
	282	{
f833bab8 SS	283	unsigned long flags;
f833bab8 SS	284
d316c57f	285	BUG_ON(dev->mode != CLOCK_EVT_MODE_UNUSED);
1b054b67 TG	286	if (!dev->cpumask) {
	287	WARN_ON(num_possible_cpus() > 1);
	288	dev->cpumask = cpumask_of(smp_processor_id());
	289	}
320ab2b0	290
b5f91da0	291	raw_spin_lock_irqsave(&clockevents_lock, flags);
d316c57f TG	292
	293	list_add(&dev->list, &clockevent_devices);
	294	clockevents_do_notify(CLOCK_EVT_NOTIFY_ADD, dev);
	295	clockevents_notify_released();
	296
b5f91da0	297	raw_spin_unlock_irqrestore(&clockevents_lock, flags);
d316c57f	298	}
c81fc2c3	299	EXPORT_SYMBOL_GPL(clockevents_register_device);
d316c57f	300
57f0fcbe TG	301	static void clockevents_config(struct clock_event_device *dev,
	302	u32 freq)
	303	{
c0e299b1	304	u64 sec;
57f0fcbe TG	305
	306	if (!(dev->features & CLOCK_EVT_FEAT_ONESHOT))
	307	return;
	308
	309	/*
	310	* Calculate the maximum number of seconds we can sleep. Limit
	311	* to 10 minutes for hardware which can program more than
	312	* 32bit ticks so we still get reasonable conversion values.
	313	*/
	314	sec = dev->max_delta_ticks;
	315	do_div(sec, freq);
	316	if (!sec)
	317	sec = 1;
	318	else if (sec > 600 && dev->max_delta_ticks > UINT_MAX)
	319	sec = 600;
	320
	321	clockevents_calc_mult_shift(dev, freq, sec);
	322	dev->min_delta_ns = clockevent_delta2ns(dev->min_delta_ticks, dev);
	323	dev->max_delta_ns = clockevent_delta2ns(dev->max_delta_ticks, dev);
	324	}
	325
	326	/**
	327	* clockevents_config_and_register - Configure and register a clock event device
	328	* @dev: device to register
	329	* @freq: The clock frequency
	330	* @min_delta: The minimum clock ticks to program in oneshot mode
	331	* @max_delta: The maximum clock ticks to program in oneshot mode
	332	*
	333	* min/max_delta can be 0 for devices which do not support oneshot mode.
	334	*/
	335	void clockevents_config_and_register(struct clock_event_device *dev,
	336	u32 freq, unsigned long min_delta,
	337	unsigned long max_delta)
	338	{
	339	dev->min_delta_ticks = min_delta;
	340	dev->max_delta_ticks = max_delta;
	341	clockevents_config(dev, freq);
	342	clockevents_register_device(dev);
	343	}
	344
80b816b7 TG	345	/**
	346	* clockevents_update_freq - Update frequency and reprogram a clock event device.
	347	* @dev: device to modify
	348	* @freq: new device frequency
	349	*
	350	* Reconfigure and reprogram a clock event device in oneshot
	351	* mode. Must be called on the cpu for which the device delivers per
	352	* cpu timer events with interrupts disabled! Returns 0 on success,
	353	* -ETIME when the event is in the past.
	354	*/
	355	int clockevents_update_freq(struct clock_event_device *dev, u32 freq)
	356	{
	357	clockevents_config(dev, freq);
	358
	359	if (dev->mode != CLOCK_EVT_MODE_ONESHOT)
	360	return 0;
	361
d1748302	362	return clockevents_program_event(dev, dev->next_event, false);
80b816b7 TG	363	}
80b816b7 TG	364
d316c57f TG	365	/*
	366	* Noop handler when we shut down an event device
	367	*/
7c1e7689	368	void clockevents_handle_noop(struct clock_event_device *dev)
d316c57f TG	369	{
	370	}
	371
	372	/**
	373	* clockevents_exchange_device - release and request clock devices
	374	* @old: device to release (can be NULL)
	375	* @new: device to request (can be NULL)
	376	*
	377	* Called from the notifier chain. clockevents_lock is held already
	378	*/
	379	void clockevents_exchange_device(struct clock_event_device *old,
	380	struct clock_event_device *new)
	381	{
	382	unsigned long flags;
	383
	384	local_irq_save(flags);
	385	/*
	386	* Caller releases a clock event device. We queue it into the
	387	* released list and do a notify add later.
	388	*/
	389	if (old) {
d316c57f TG	390	clockevents_set_mode(old, CLOCK_EVT_MODE_UNUSED);
	391	list_del(&old->list);
	392	list_add(&old->list, &clockevents_released);
	393	}
	394
	395	if (new) {
	396	BUG_ON(new->mode != CLOCK_EVT_MODE_UNUSED);
2344abbc	397	clockevents_shutdown(new);
d316c57f TG	398	}
	399	local_irq_restore(flags);
	400	}
	401
de68d9b1	402	#ifdef CONFIG_GENERIC_CLOCKEVENTS
d316c57f TG	403	/**
	404	* clockevents_notify - notification about relevant events
	405	*/
	406	void clockevents_notify(unsigned long reason, void *arg)
	407	{
bb6eddf7	408	struct clock_event_device dev, tmp;
f833bab8	409	unsigned long flags;
bb6eddf7	410	int cpu;
0b858e6f	411
b5f91da0	412	raw_spin_lock_irqsave(&clockevents_lock, flags);
d316c57f TG	413	clockevents_do_notify(reason, arg);
	414
	415	switch (reason) {
	416	case CLOCK_EVT_NOTIFY_CPU_DEAD:
	417	/*
	418	* Unregister the clock event devices which were
	419	* released from the users in the notify chain.
	420	*/
bb6eddf7 TG	421	list_for_each_entry_safe(dev, tmp, &clockevents_released, list)
	422	list_del(&dev->list);
	423	/*
	424	* Now check whether the CPU has left unused per cpu devices
	425	*/
	426	cpu = ((int )arg);
	427	list_for_each_entry_safe(dev, tmp, &clockevent_devices, list) {
	428	if (cpumask_test_cpu(cpu, dev->cpumask) &&
ea9d8e3f XF	429	cpumask_weight(dev->cpumask) == 1 &&
ea9d8e3f XF	430	!tick_is_broadcast_device(dev)) {
bb6eddf7 TG	431	BUG_ON(dev->mode != CLOCK_EVT_MODE_UNUSED);
	432	list_del(&dev->list);
	433	}
	434	}
d316c57f TG	435	break;
	436	default:
	437	break;
	438	}
b5f91da0	439	raw_spin_unlock_irqrestore(&clockevents_lock, flags);
d316c57f TG	440	}
d316c57f TG	441	EXPORT_SYMBOL_GPL(clockevents_notify);
de68d9b1	442	#endif