[mirror_ubuntu-bionic-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/smp.h>
#include <linux/device.h>

#include "tick-internal.h"

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

/*
 * 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);
		tick_check_new_device(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);
	tick_check_new_device(dev);
	clockevents_notify_released();

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

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);
}
EXPORT_SYMBOL_GPL(clockevents_config_and_register);

/**
 * 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) {
		module_put(old->owner);
		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);
}

/**
 * clockevents_suspend - suspend clock devices
 */
void clockevents_suspend(void)
{
	struct clock_event_device *dev;

	list_for_each_entry_reverse(dev, &clockevent_devices, list)
		if (dev->suspend)
			dev->suspend(dev);
}

/**
 * clockevents_resume - resume clock devices
 */
void clockevents_resume(void)
{
	struct clock_event_device *dev;

	list_for_each_entry(dev, &clockevent_devices, list)
		if (dev->resume)
			dev->resume(dev);
}

#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);

	switch (reason) {
	case CLOCK_EVT_NOTIFY_BROADCAST_ON:
	case CLOCK_EVT_NOTIFY_BROADCAST_OFF:
	case CLOCK_EVT_NOTIFY_BROADCAST_FORCE:
		tick_broadcast_on_off(reason, arg);
		break;

	case CLOCK_EVT_NOTIFY_BROADCAST_ENTER:
	case CLOCK_EVT_NOTIFY_BROADCAST_EXIT:
		tick_broadcast_oneshot_control(reason);
		break;

	case CLOCK_EVT_NOTIFY_CPU_DYING:
		tick_handover_do_timer(arg);
		break;

	case CLOCK_EVT_NOTIFY_SUSPEND:
		tick_suspend();
		tick_suspend_broadcast();
		break;

	case CLOCK_EVT_NOTIFY_RESUME:
		tick_resume();
		break;

	case CLOCK_EVT_NOTIFY_CPU_DEAD:
		tick_shutdown_broadcast_oneshot(arg);
		tick_shutdown_broadcast(arg);
		tick_shutdown(arg);
		/*
		 * 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);

#ifdef CONFIG_SYSFS
struct bus_type clockevents_subsys = {
	.name		= "clockevents",
	.dev_name       = "clockevent",
};

static DEFINE_PER_CPU(struct device, tick_percpu_dev);
static struct tick_device *tick_get_tick_dev(struct device *dev);

static ssize_t sysfs_show_current_tick_dev(struct device *dev,
					   struct device_attribute *attr,
					   char *buf)
{
	struct tick_device *td;
	ssize_t count = 0;

	raw_spin_lock_irq(&clockevents_lock);
	td = tick_get_tick_dev(dev);
	if (td && td->evtdev)
		count = snprintf(buf, PAGE_SIZE, "%s\n", td->evtdev->name);
	raw_spin_unlock_irq(&clockevents_lock);
	return count;
}
static DEVICE_ATTR(current_device, 0444, sysfs_show_current_tick_dev, NULL);

#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
static struct device tick_bc_dev = {
	.init_name	= "broadcast",
	.id		= 0,
	.bus		= &clockevents_subsys,
};

static struct tick_device *tick_get_tick_dev(struct device *dev)
{
	return dev == &tick_bc_dev ? tick_get_broadcast_device() :
		&per_cpu(tick_cpu_device, dev->id);
}

static __init int tick_broadcast_init_sysfs(void)
{
	int err = device_register(&tick_bc_dev);

	if (!err)
		err = device_create_file(&tick_bc_dev, &dev_attr_current_device);
	return err;
}
#else
static struct tick_device *tick_get_tick_dev(struct device *dev)
{
	return &per_cpu(tick_cpu_device, dev->id);
}
static inline int tick_broadcast_init_sysfs(void) { return 0; }
#endif

static int __init tick_init_sysfs(void)
{
	int cpu;

	for_each_possible_cpu(cpu) {
		struct device *dev = &per_cpu(tick_percpu_dev, cpu);
		int err;

		dev->id = cpu;
		dev->bus = &clockevents_subsys;
		err = device_register(dev);
		if (!err)
			err = device_create_file(dev, &dev_attr_current_device);
		if (err)
			return err;
	}
	return tick_broadcast_init_sysfs();
}

static int __init clockevents_init_sysfs(void)
{
	int err = subsys_system_register(&clockevents_subsys, NULL);

	if (!err)
		err = tick_init_sysfs();
	return err;
}
device_initcall(clockevents_init_sysfs);
#endif /* SYSFS */

#endif /* GENERIC_CLOCK_EVENTS */
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>
d316c57f	18	#include <linux/smp.h>
501f8670	19	#include <linux/device.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);
d316c57f	26	/* Protection for the above */
b5f91da0	27	static DEFINE_RAW_SPINLOCK(clockevents_lock);
d316c57f TG	28
	29	/**
	30	* clockevents_delta2ns - Convert a latch value (device ticks) to nanoseconds
	31	* @latch: value to convert
	32	* @evt: pointer to clock event device descriptor
	33	*
	34	* Math helper, returns latch value converted to nanoseconds (bound checked)
	35	*/
97813f2f	36	u64 clockevent_delta2ns(unsigned long latch, struct clock_event_device *evt)
d316c57f	37	{
97813f2f	38	u64 clc = (u64) latch << evt->shift;
d316c57f	39
45fe4fe1 IM	40	if (unlikely(!evt->mult)) {
	41	evt->mult = 1;
	42	WARN_ON(1);
	43	}
	44
d316c57f TG	45	do_div(clc, evt->mult);
	46	if (clc < 1000)
	47	clc = 1000;
97813f2f JH	48	if (clc > KTIME_MAX)
97813f2f JH	49	clc = KTIME_MAX;
d316c57f	50
97813f2f	51	return clc;
d316c57f	52	}
c81fc2c3	53	EXPORT_SYMBOL_GPL(clockevent_delta2ns);
d316c57f TG	54
	55	/**
	56	* clockevents_set_mode - set the operating mode of a clock event device
	57	* @dev: device to modify
	58	* @mode: new mode
	59	*
	60	* Must be called with interrupts disabled !
	61	*/
	62	void clockevents_set_mode(struct clock_event_device *dev,
	63	enum clock_event_mode mode)
	64	{
	65	if (dev->mode != mode) {
	66	dev->set_mode(mode, dev);
	67	dev->mode = mode;
2d68259d MD	68
	69	/*
	70	* A nsec2cyc multiplicator of 0 is invalid and we'd crash
	71	* on it, so fix it up and emit a warning:
	72	*/
	73	if (mode == CLOCK_EVT_MODE_ONESHOT) {
	74	if (unlikely(!dev->mult)) {
	75	dev->mult = 1;
	76	WARN_ON(1);
	77	}
	78	}
d316c57f TG	79	}
	80	}
	81
2344abbc TG	82	/**
	83	* clockevents_shutdown - shutdown the device and clear next_event
	84	* @dev: device to shutdown
	85	*/
	86	void clockevents_shutdown(struct clock_event_device *dev)
	87	{
	88	clockevents_set_mode(dev, CLOCK_EVT_MODE_SHUTDOWN);
	89	dev->next_event.tv64 = KTIME_MAX;
	90	}
	91
d1748302 MS	92	#ifdef CONFIG_GENERIC_CLOCKEVENTS_MIN_ADJUST
	93
	94	/* Limit min_delta to a jiffie */
	95	#define MIN_DELTA_LIMIT (NSEC_PER_SEC / HZ)
	96
	97	/**
	98	* clockevents_increase_min_delta - raise minimum delta of a clock event device
	99	* @dev: device to increase the minimum delta
	100	*
	101	* Returns 0 on success, -ETIME when the minimum delta reached the limit.
	102	*/
	103	static int clockevents_increase_min_delta(struct clock_event_device *dev)
	104	{
	105	/* Nothing to do if we already reached the limit */
	106	if (dev->min_delta_ns >= MIN_DELTA_LIMIT) {
	107	printk(KERN_WARNING "CE: Reprogramming failure. Giving up\n");
	108	dev->next_event.tv64 = KTIME_MAX;
	109	return -ETIME;
	110	}
	111
	112	if (dev->min_delta_ns < 5000)
	113	dev->min_delta_ns = 5000;
	114	else
	115	dev->min_delta_ns += dev->min_delta_ns >> 1;
	116
	117	if (dev->min_delta_ns > MIN_DELTA_LIMIT)
	118	dev->min_delta_ns = MIN_DELTA_LIMIT;
	119
	120	printk(KERN_WARNING "CE: %s increased min_delta_ns to %llu nsec\n",
	121	dev->name ? dev->name : "?",
	122	(unsigned long long) dev->min_delta_ns);
	123	return 0;
	124	}
	125
	126	/**
	127	* clockevents_program_min_delta - Set clock event device to the minimum delay.
	128	* @dev: device to program
	129	*
	130	* Returns 0 on success, -ETIME when the retry loop failed.
	131	*/
	132	static int clockevents_program_min_delta(struct clock_event_device *dev)
	133	{
	134	unsigned long long clc;
	135	int64_t delta;
	136	int i;
	137
	138	for (i = 0;;) {
	139	delta = dev->min_delta_ns;
	140	dev->next_event = ktime_add_ns(ktime_get(), delta);
	141
	142	if (dev->mode == CLOCK_EVT_MODE_SHUTDOWN)
	143	return 0;
	144
	145	dev->retries++;
	146	clc = ((unsigned long long) delta * dev->mult) >> dev->shift;
	147	if (dev->set_next_event((unsigned long) clc, dev) == 0)
	148	return 0;
	149
	150	if (++i > 2) {
	151	/*
	152	* We tried 3 times to program the device with the
	153	* given min_delta_ns. Try to increase the minimum
	154	* delta, if that fails as well get out of here.
	155	*/
156	if (clockevents_increase_min_delta(dev))
157	return -ETIME;
158	i = 0;
159	}
160	}
161	}
162
163	#else /* CONFIG_GENERIC_CLOCKEVENTS_MIN_ADJUST */
164
165	/**
166	* clockevents_program_min_delta - Set clock event device to the minimum delay.
167	* @dev: device to program
168	*
169	* Returns 0 on success, -ETIME when the retry loop failed.
170	*/
171	static int clockevents_program_min_delta(struct clock_event_device *dev)
172	{
173	unsigned long long clc;
174	int64_t delta;
175
176	delta = dev->min_delta_ns;
177	dev->next_event = ktime_add_ns(ktime_get(), delta);
178
179	if (dev->mode == CLOCK_EVT_MODE_SHUTDOWN)
180	return 0;
181
182	dev->retries++;
183	clc = ((unsigned long long) delta * dev->mult) >> dev->shift;
184	return dev->set_next_event((unsigned long) clc, dev);
185	}
186
187	#endif /* CONFIG_GENERIC_CLOCKEVENTS_MIN_ADJUST */
188
d316c57f TG	189	/**
d316c57f TG	190	* clockevents_program_event - Reprogram the clock event device.
d1748302	191	* @dev: device to program
d316c57f	192	* @expires: absolute expiry time (monotonic clock)
d1748302	193	* @force: program minimum delay if expires can not be set
d316c57f TG	194	*
	195	* Returns 0 on success, -ETIME when the event is in the past.
	196	*/
	197	int clockevents_program_event(struct clock_event_device *dev, ktime_t expires,
d1748302	198	bool force)
d316c57f TG	199	{
	200	unsigned long long clc;
	201	int64_t delta;
d1748302	202	int rc;
d316c57f	203
167b1de3 TG	204	if (unlikely(expires.tv64 < 0)) {
	205	WARN_ON_ONCE(1);
	206	return -ETIME;
	207	}
	208
d316c57f TG	209	dev->next_event = expires;
	210
	211	if (dev->mode == CLOCK_EVT_MODE_SHUTDOWN)
	212	return 0;
	213
65516f8a MS	214	/* Shortcut for clockevent devices that can deal with ktime. */
	215	if (dev->features & CLOCK_EVT_FEAT_KTIME)
	216	return dev->set_next_ktime(expires, dev);
	217
d1748302 MS	218	delta = ktime_to_ns(ktime_sub(expires, ktime_get()));
	219	if (delta <= 0)
	220	return force ? clockevents_program_min_delta(dev) : -ETIME;
d316c57f	221
d1748302 MS	222	delta = min(delta, (int64_t) dev->max_delta_ns);
d1748302 MS	223	delta = max(delta, (int64_t) dev->min_delta_ns);
d316c57f	224
d1748302 MS	225	clc = ((unsigned long long) delta * dev->mult) >> dev->shift;
	226	rc = dev->set_next_event((unsigned long) clc, dev);
	227
	228	return (rc && force) ? clockevents_program_min_delta(dev) : rc;
d316c57f TG	229	}
d316c57f TG	230
d316c57f	231	/*
3eb05676	232	* Called after a notify add to make devices available which were
d316c57f TG	233	* released from the notifier call.
	234	*/
	235	static void clockevents_notify_released(void)
	236	{
	237	struct clock_event_device *dev;
	238
	239	while (!list_empty(&clockevents_released)) {
	240	dev = list_entry(clockevents_released.next,
	241	struct clock_event_device, list);
	242	list_del(&dev->list);
	243	list_add(&dev->list, &clockevent_devices);
7172a286	244	tick_check_new_device(dev);
d316c57f TG	245	}
	246	}
	247
	248	/**
	249	* clockevents_register_device - register a clock event device
	250	* @dev: device to register
	251	*/
	252	void clockevents_register_device(struct clock_event_device *dev)
	253	{
f833bab8 SS	254	unsigned long flags;
f833bab8 SS	255
d316c57f	256	BUG_ON(dev->mode != CLOCK_EVT_MODE_UNUSED);
1b054b67 TG	257	if (!dev->cpumask) {
	258	WARN_ON(num_possible_cpus() > 1);
	259	dev->cpumask = cpumask_of(smp_processor_id());
	260	}
320ab2b0	261
b5f91da0	262	raw_spin_lock_irqsave(&clockevents_lock, flags);
d316c57f TG	263
d316c57f TG	264	list_add(&dev->list, &clockevent_devices);
7172a286	265	tick_check_new_device(dev);
d316c57f TG	266	clockevents_notify_released();
d316c57f TG	267
b5f91da0	268	raw_spin_unlock_irqrestore(&clockevents_lock, flags);
d316c57f	269	}
c81fc2c3	270	EXPORT_SYMBOL_GPL(clockevents_register_device);
d316c57f	271
e5400321	272	void clockevents_config(struct clock_event_device *dev, u32 freq)
57f0fcbe	273	{
c0e299b1	274	u64 sec;
57f0fcbe TG	275
	276	if (!(dev->features & CLOCK_EVT_FEAT_ONESHOT))
	277	return;
	278
	279	/*
	280	* Calculate the maximum number of seconds we can sleep. Limit
	281	* to 10 minutes for hardware which can program more than
	282	* 32bit ticks so we still get reasonable conversion values.
	283	*/
	284	sec = dev->max_delta_ticks;
	285	do_div(sec, freq);
	286	if (!sec)
	287	sec = 1;
	288	else if (sec > 600 && dev->max_delta_ticks > UINT_MAX)
	289	sec = 600;
	290
	291	clockevents_calc_mult_shift(dev, freq, sec);
	292	dev->min_delta_ns = clockevent_delta2ns(dev->min_delta_ticks, dev);
	293	dev->max_delta_ns = clockevent_delta2ns(dev->max_delta_ticks, dev);
	294	}
	295
	296	/**
	297	* clockevents_config_and_register - Configure and register a clock event device
	298	* @dev: device to register
	299	* @freq: The clock frequency
	300	* @min_delta: The minimum clock ticks to program in oneshot mode
	301	* @max_delta: The maximum clock ticks to program in oneshot mode
	302	*
	303	* min/max_delta can be 0 for devices which do not support oneshot mode.
	304	*/
	305	void clockevents_config_and_register(struct clock_event_device *dev,
	306	u32 freq, unsigned long min_delta,
	307	unsigned long max_delta)
	308	{
	309	dev->min_delta_ticks = min_delta;
	310	dev->max_delta_ticks = max_delta;
	311	clockevents_config(dev, freq);
	312	clockevents_register_device(dev);
	313	}
c35ef95c	314	EXPORT_SYMBOL_GPL(clockevents_config_and_register);
57f0fcbe	315
80b816b7 TG	316	/**
	317	* clockevents_update_freq - Update frequency and reprogram a clock event device.
	318	* @dev: device to modify
	319	* @freq: new device frequency
	320	*
	321	* Reconfigure and reprogram a clock event device in oneshot
	322	* mode. Must be called on the cpu for which the device delivers per
	323	* cpu timer events with interrupts disabled! Returns 0 on success,
	324	* -ETIME when the event is in the past.
	325	*/
	326	int clockevents_update_freq(struct clock_event_device *dev, u32 freq)
	327	{
	328	clockevents_config(dev, freq);
	329
	330	if (dev->mode != CLOCK_EVT_MODE_ONESHOT)
	331	return 0;
	332
d1748302	333	return clockevents_program_event(dev, dev->next_event, false);
80b816b7 TG	334	}
80b816b7 TG	335
d316c57f TG	336	/*
	337	* Noop handler when we shut down an event device
	338	*/
7c1e7689	339	void clockevents_handle_noop(struct clock_event_device *dev)
d316c57f TG	340	{
	341	}
	342
	343	/**
	344	* clockevents_exchange_device - release and request clock devices
	345	* @old: device to release (can be NULL)
	346	* @new: device to request (can be NULL)
	347	*
	348	* Called from the notifier chain. clockevents_lock is held already
	349	*/
	350	void clockevents_exchange_device(struct clock_event_device *old,
	351	struct clock_event_device *new)
	352	{
	353	unsigned long flags;
	354
	355	local_irq_save(flags);
	356	/*
	357	* Caller releases a clock event device. We queue it into the
	358	* released list and do a notify add later.
	359	*/
	360	if (old) {
ccf33d68	361	module_put(old->owner);
d316c57f TG	362	clockevents_set_mode(old, CLOCK_EVT_MODE_UNUSED);
	363	list_del(&old->list);
	364	list_add(&old->list, &clockevents_released);
	365	}
	366
	367	if (new) {
	368	BUG_ON(new->mode != CLOCK_EVT_MODE_UNUSED);
2344abbc	369	clockevents_shutdown(new);
d316c57f TG	370	}
	371	local_irq_restore(flags);
	372	}
	373
adc78e6b RW	374	/**
	375	* clockevents_suspend - suspend clock devices
	376	*/
	377	void clockevents_suspend(void)
	378	{
	379	struct clock_event_device *dev;
	380
	381	list_for_each_entry_reverse(dev, &clockevent_devices, list)
	382	if (dev->suspend)
	383	dev->suspend(dev);
	384	}
	385
	386	/**
	387	* clockevents_resume - resume clock devices
	388	*/
	389	void clockevents_resume(void)
	390	{
	391	struct clock_event_device *dev;
	392
	393	list_for_each_entry(dev, &clockevent_devices, list)
	394	if (dev->resume)
	395	dev->resume(dev);
	396	}
	397
de68d9b1	398	#ifdef CONFIG_GENERIC_CLOCKEVENTS
d316c57f TG	399	/**
	400	* clockevents_notify - notification about relevant events
	401	*/
	402	void clockevents_notify(unsigned long reason, void *arg)
	403	{
bb6eddf7	404	struct clock_event_device dev, tmp;
f833bab8	405	unsigned long flags;
bb6eddf7	406	int cpu;
0b858e6f	407
b5f91da0	408	raw_spin_lock_irqsave(&clockevents_lock, flags);
d316c57f TG	409
d316c57f TG	410	switch (reason) {
8c53daf6 TG	411	case CLOCK_EVT_NOTIFY_BROADCAST_ON:
	412	case CLOCK_EVT_NOTIFY_BROADCAST_OFF:
	413	case CLOCK_EVT_NOTIFY_BROADCAST_FORCE:
	414	tick_broadcast_on_off(reason, arg);
	415	break;
	416
	417	case CLOCK_EVT_NOTIFY_BROADCAST_ENTER:
	418	case CLOCK_EVT_NOTIFY_BROADCAST_EXIT:
	419	tick_broadcast_oneshot_control(reason);
	420	break;
	421
	422	case CLOCK_EVT_NOTIFY_CPU_DYING:
	423	tick_handover_do_timer(arg);
	424	break;
	425
	426	case CLOCK_EVT_NOTIFY_SUSPEND:
	427	tick_suspend();
	428	tick_suspend_broadcast();
	429	break;
	430
	431	case CLOCK_EVT_NOTIFY_RESUME:
	432	tick_resume();
	433	break;
	434
d316c57f	435	case CLOCK_EVT_NOTIFY_CPU_DEAD:
8c53daf6 TG	436	tick_shutdown_broadcast_oneshot(arg);
	437	tick_shutdown_broadcast(arg);
	438	tick_shutdown(arg);
d316c57f TG	439	/*
	440	* Unregister the clock event devices which were
	441	* released from the users in the notify chain.
	442	*/
bb6eddf7 TG	443	list_for_each_entry_safe(dev, tmp, &clockevents_released, list)
	444	list_del(&dev->list);
	445	/*
	446	* Now check whether the CPU has left unused per cpu devices
	447	*/
	448	cpu = ((int )arg);
	449	list_for_each_entry_safe(dev, tmp, &clockevent_devices, list) {
	450	if (cpumask_test_cpu(cpu, dev->cpumask) &&
ea9d8e3f XF	451	cpumask_weight(dev->cpumask) == 1 &&
ea9d8e3f XF	452	!tick_is_broadcast_device(dev)) {
bb6eddf7 TG	453	BUG_ON(dev->mode != CLOCK_EVT_MODE_UNUSED);
	454	list_del(&dev->list);
	455	}
	456	}
d316c57f TG	457	break;
	458	default:
	459	break;
	460	}
b5f91da0	461	raw_spin_unlock_irqrestore(&clockevents_lock, flags);
d316c57f TG	462	}
d316c57f TG	463	EXPORT_SYMBOL_GPL(clockevents_notify);
501f8670 TG	464
	465	#ifdef CONFIG_SYSFS
	466	struct bus_type clockevents_subsys = {
	467	.name = "clockevents",
	468	.dev_name = "clockevent",
	469	};
	470
	471	static DEFINE_PER_CPU(struct device, tick_percpu_dev);
	472	static struct tick_device tick_get_tick_dev(struct device dev);
	473
	474	static ssize_t sysfs_show_current_tick_dev(struct device *dev,
	475	struct device_attribute *attr,
	476	char *buf)
	477	{
	478	struct tick_device *td;
	479	ssize_t count = 0;
	480
	481	raw_spin_lock_irq(&clockevents_lock);
	482	td = tick_get_tick_dev(dev);
	483	if (td && td->evtdev)
	484	count = snprintf(buf, PAGE_SIZE, "%s\n", td->evtdev->name);
	485	raw_spin_unlock_irq(&clockevents_lock);
	486	return count;
	487	}
	488	static DEVICE_ATTR(current_device, 0444, sysfs_show_current_tick_dev, NULL);
	489
	490	#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
	491	static struct device tick_bc_dev = {
	492	.init_name = "broadcast",
	493	.id = 0,
	494	.bus = &clockevents_subsys,
	495	};
	496
	497	static struct tick_device tick_get_tick_dev(struct device dev)
	498	{
	499	return dev == &tick_bc_dev ? tick_get_broadcast_device() :
	500	&per_cpu(tick_cpu_device, dev->id);
	501	}
	502
	503	static __init int tick_broadcast_init_sysfs(void)
	504	{
	505	int err = device_register(&tick_bc_dev);
	506
	507	if (!err)
	508	err = device_create_file(&tick_bc_dev, &dev_attr_current_device);
	509	return err;
	510	}
	511	#else
	512	static struct tick_device tick_get_tick_dev(struct device dev)
	513	{
	514	return &per_cpu(tick_cpu_device, dev->id);
	515	}
	516	static inline int tick_broadcast_init_sysfs(void) { return 0; }
de68d9b1	517	#endif
501f8670 TG	518
	519	static int __init tick_init_sysfs(void)
	520	{
	521	int cpu;
	522
	523	for_each_possible_cpu(cpu) {
	524	struct device *dev = &per_cpu(tick_percpu_dev, cpu);
	525	int err;
	526
	527	dev->id = cpu;
	528	dev->bus = &clockevents_subsys;
	529	err = device_register(dev);
	530	if (!err)
	531	err = device_create_file(dev, &dev_attr_current_device);
	532	if (err)
	533	return err;
	534	}
	535	return tick_broadcast_init_sysfs();
	536	}
	537
	538	static int __init clockevents_init_sysfs(void)
	539	{
	540	int err = subsys_system_register(&clockevents_subsys, NULL);
	541
	542	if (!err)
	543	err = tick_init_sysfs();
	544	return err;
	545	}
	546	device_initcall(clockevents_init_sysfs);
	547	#endif /* SYSFS */
	548
	549	#endif /* GENERIC_CLOCK_EVENTS */