[mirror_ubuntu-artful-kernel.git] / kernel / time / tick-broadcast.c

/*
 * linux/kernel/time/tick-broadcast.c
 *
 * This file contains functions which emulate a local clock-event
 * device via a broadcast event source.
 *
 * 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/cpu.h>
#include <linux/err.h>
#include <linux/hrtimer.h>
#include <linux/interrupt.h>
#include <linux/percpu.h>
#include <linux/profile.h>
#include <linux/sched.h>
#include <linux/tick.h>

#include "tick-internal.h"

/*
 * Broadcast support for broken x86 hardware, where the local apic
 * timer stops in C3 state.
 */

struct tick_device tick_broadcast_device;
static cpumask_t tick_broadcast_mask;
static DEFINE_SPINLOCK(tick_broadcast_lock);
static int tick_broadcast_force;

#ifdef CONFIG_TICK_ONESHOT
static void tick_broadcast_clear_oneshot(int cpu);
#else
static inline void tick_broadcast_clear_oneshot(int cpu) { }
#endif

/*
 * Debugging: see timer_list.c
 */
struct tick_device *tick_get_broadcast_device(void)
{
	return &tick_broadcast_device;
}

cpumask_t *tick_get_broadcast_mask(void)
{
	return &tick_broadcast_mask;
}

/*
 * Start the device in periodic mode
 */
static void tick_broadcast_start_periodic(struct clock_event_device *bc)
{
	if (bc)
		tick_setup_periodic(bc, 1);
}

/*
 * Check, if the device can be utilized as broadcast device:
 */
int tick_check_broadcast_device(struct clock_event_device *dev)
{
	if ((tick_broadcast_device.evtdev &&
	     tick_broadcast_device.evtdev->rating >= dev->rating) ||
	     (dev->features & CLOCK_EVT_FEAT_C3STOP))
		return 0;

	clockevents_exchange_device(NULL, dev);
	tick_broadcast_device.evtdev = dev;
	if (!cpus_empty(tick_broadcast_mask))
		tick_broadcast_start_periodic(dev);
	return 1;
}

/*
 * Check, if the device is the broadcast device
 */
int tick_is_broadcast_device(struct clock_event_device *dev)
{
	return (dev && tick_broadcast_device.evtdev == dev);
}

/*
 * Check, if the device is disfunctional and a place holder, which
 * needs to be handled by the broadcast device.
 */
int tick_device_uses_broadcast(struct clock_event_device *dev, int cpu)
{
	unsigned long flags;
	int ret = 0;

	spin_lock_irqsave(&tick_broadcast_lock, flags);

	/*
	 * Devices might be registered with both periodic and oneshot
	 * mode disabled. This signals, that the device needs to be
	 * operated from the broadcast device and is a placeholder for
	 * the cpu local device.
	 */
	if (!tick_device_is_functional(dev)) {
		dev->event_handler = tick_handle_periodic;
		cpu_set(cpu, tick_broadcast_mask);
		tick_broadcast_start_periodic(tick_broadcast_device.evtdev);
		ret = 1;
	} else {
		/*
		 * When the new device is not affected by the stop
		 * feature and the cpu is marked in the broadcast mask
		 * then clear the broadcast bit.
		 */
		if (!(dev->features & CLOCK_EVT_FEAT_C3STOP)) {
			int cpu = smp_processor_id();

			cpu_clear(cpu, tick_broadcast_mask);
			tick_broadcast_clear_oneshot(cpu);
		}
	}
	spin_unlock_irqrestore(&tick_broadcast_lock, flags);
	return ret;
}

/*
 * Broadcast the event to the cpus, which are set in the mask
 */
static void tick_do_broadcast(cpumask_t mask)
{
	int cpu = smp_processor_id();
	struct tick_device *td;

	/*
	 * Check, if the current cpu is in the mask
	 */
	if (cpu_isset(cpu, mask)) {
		cpu_clear(cpu, mask);
		td = &per_cpu(tick_cpu_device, cpu);
		td->evtdev->event_handler(td->evtdev);
	}

	if (!cpus_empty(mask)) {
		/*
		 * It might be necessary to actually check whether the devices
		 * have different broadcast functions. For now, just use the
		 * one of the first device. This works as long as we have this
		 * misfeature only on x86 (lapic)
		 */
		cpu = first_cpu(mask);
		td = &per_cpu(tick_cpu_device, cpu);
		td->evtdev->broadcast(mask);
	}
}

/*
 * Periodic broadcast:
 * - invoke the broadcast handlers
 */
static void tick_do_periodic_broadcast(void)
{
	cpumask_t mask;

	spin_lock(&tick_broadcast_lock);

	cpus_and(mask, cpu_online_map, tick_broadcast_mask);
	tick_do_broadcast(mask);

	spin_unlock(&tick_broadcast_lock);
}

/*
 * Event handler for periodic broadcast ticks
 */
static void tick_handle_periodic_broadcast(struct clock_event_device *dev)
{
	tick_do_periodic_broadcast();

	/*
	 * The device is in periodic mode. No reprogramming necessary:
	 */
	if (dev->mode == CLOCK_EVT_MODE_PERIODIC)
		return;

	/*
	 * Setup the next period for devices, which do not have
	 * periodic mode:
	 */
	for (;;) {
		ktime_t next = ktime_add(dev->next_event, tick_period);

		if (!clockevents_program_event(dev, next, ktime_get()))
			return;
		tick_do_periodic_broadcast();
	}
}

/*
 * Powerstate information: The system enters/leaves a state, where
 * affected devices might stop
 */
static void tick_do_broadcast_on_off(void *why)
{
	struct clock_event_device *bc, *dev;
	struct tick_device *td;
	unsigned long flags, *reason = why;
	int cpu;

	spin_lock_irqsave(&tick_broadcast_lock, flags);

	cpu = smp_processor_id();
	td = &per_cpu(tick_cpu_device, cpu);
	dev = td->evtdev;
	bc = tick_broadcast_device.evtdev;

	/*
	 * Is the device not affected by the powerstate ?
	 */
	if (!dev || !(dev->features & CLOCK_EVT_FEAT_C3STOP))
		goto out;

	if (!tick_device_is_functional(dev))
		goto out;

	switch (*reason) {
	case CLOCK_EVT_NOTIFY_BROADCAST_ON:
	case CLOCK_EVT_NOTIFY_BROADCAST_FORCE:
		if (!cpu_isset(cpu, tick_broadcast_mask)) {
			cpu_set(cpu, tick_broadcast_mask);
			if (td->mode == TICKDEV_MODE_PERIODIC)
				clockevents_set_mode(dev,
						     CLOCK_EVT_MODE_SHUTDOWN);
		}
		if (*reason == CLOCK_EVT_NOTIFY_BROADCAST_FORCE)
			tick_broadcast_force = 1;
		break;
	case CLOCK_EVT_NOTIFY_BROADCAST_OFF:
		if (!tick_broadcast_force &&
		    cpu_isset(cpu, tick_broadcast_mask)) {
			cpu_clear(cpu, tick_broadcast_mask);
			if (td->mode == TICKDEV_MODE_PERIODIC)
				tick_setup_periodic(dev, 0);
		}
		break;
	}

	if (cpus_empty(tick_broadcast_mask))
		clockevents_set_mode(bc, CLOCK_EVT_MODE_SHUTDOWN);
	else {
		if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC)
			tick_broadcast_start_periodic(bc);
		else
			tick_broadcast_setup_oneshot(bc);
	}
out:
	spin_unlock_irqrestore(&tick_broadcast_lock, flags);
}

/*
 * Powerstate information: The system enters/leaves a state, where
 * affected devices might stop.
 */
void tick_broadcast_on_off(unsigned long reason, int *oncpu)
{
	if (!cpu_isset(*oncpu, cpu_online_map))
		printk(KERN_ERR "tick-broadcast: ignoring broadcast for "
		       "offline CPU #%d\n", *oncpu);
	else
		smp_call_function_single(*oncpu, tick_do_broadcast_on_off,
					 &reason, 1, 1);
}

/*
 * Set the periodic handler depending on broadcast on/off
 */
void tick_set_periodic_handler(struct clock_event_device *dev, int broadcast)
{
	if (!broadcast)
		dev->event_handler = tick_handle_periodic;
	else
		dev->event_handler = tick_handle_periodic_broadcast;
}

/*
 * Remove a CPU from broadcasting
 */
void tick_shutdown_broadcast(unsigned int *cpup)
{
	struct clock_event_device *bc;
	unsigned long flags;
	unsigned int cpu = *cpup;

	spin_lock_irqsave(&tick_broadcast_lock, flags);

	bc = tick_broadcast_device.evtdev;
	cpu_clear(cpu, tick_broadcast_mask);

	if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC) {
		if (bc && cpus_empty(tick_broadcast_mask))
			clockevents_set_mode(bc, CLOCK_EVT_MODE_SHUTDOWN);
	}

	spin_unlock_irqrestore(&tick_broadcast_lock, flags);
}

void tick_suspend_broadcast(void)
{
	struct clock_event_device *bc;
	unsigned long flags;

	spin_lock_irqsave(&tick_broadcast_lock, flags);

	bc = tick_broadcast_device.evtdev;
	if (bc)
		clockevents_set_mode(bc, CLOCK_EVT_MODE_SHUTDOWN);

	spin_unlock_irqrestore(&tick_broadcast_lock, flags);
}

int tick_resume_broadcast(void)
{
	struct clock_event_device *bc;
	unsigned long flags;
	int broadcast = 0;

	spin_lock_irqsave(&tick_broadcast_lock, flags);

	bc = tick_broadcast_device.evtdev;

	if (bc) {
		clockevents_set_mode(bc, CLOCK_EVT_MODE_RESUME);

		switch (tick_broadcast_device.mode) {
		case TICKDEV_MODE_PERIODIC:
			if(!cpus_empty(tick_broadcast_mask))
				tick_broadcast_start_periodic(bc);
			broadcast = cpu_isset(smp_processor_id(),
					      tick_broadcast_mask);
			break;
		case TICKDEV_MODE_ONESHOT:
			broadcast = tick_resume_broadcast_oneshot(bc);
			break;
		}
	}
	spin_unlock_irqrestore(&tick_broadcast_lock, flags);

	return broadcast;
}


#ifdef CONFIG_TICK_ONESHOT

static cpumask_t tick_broadcast_oneshot_mask;

/*
 * Debugging: see timer_list.c
 */
cpumask_t *tick_get_broadcast_oneshot_mask(void)
{
	return &tick_broadcast_oneshot_mask;
}

static int tick_broadcast_set_event(ktime_t expires, int force)
{
	struct clock_event_device *bc = tick_broadcast_device.evtdev;
	ktime_t now = ktime_get();
	int res;

	for(;;) {
		res = clockevents_program_event(bc, expires, now);
		if (!res || !force)
			return res;
		now = ktime_get();
		expires = ktime_add(now, ktime_set(0, bc->min_delta_ns));
	}
}

int tick_resume_broadcast_oneshot(struct clock_event_device *bc)
{
	clockevents_set_mode(bc, CLOCK_EVT_MODE_ONESHOT);
	return 0;
}

/*
 * Handle oneshot mode broadcasting
 */
static void tick_handle_oneshot_broadcast(struct clock_event_device *dev)
{
	struct tick_device *td;
	cpumask_t mask;
	ktime_t now, next_event;
	int cpu;

	spin_lock(&tick_broadcast_lock);
again:
	dev->next_event.tv64 = KTIME_MAX;
	next_event.tv64 = KTIME_MAX;
	mask = CPU_MASK_NONE;
	now = ktime_get();
	/* Find all expired events */
	for (cpu = first_cpu(tick_broadcast_oneshot_mask); cpu != NR_CPUS;
	     cpu = next_cpu(cpu, tick_broadcast_oneshot_mask)) {
		td = &per_cpu(tick_cpu_device, cpu);
		if (td->evtdev->next_event.tv64 <= now.tv64)
			cpu_set(cpu, mask);
		else if (td->evtdev->next_event.tv64 < next_event.tv64)
			next_event.tv64 = td->evtdev->next_event.tv64;
	}

	/*
	 * Wakeup the cpus which have an expired event.
	 */
	tick_do_broadcast(mask);

	/*
	 * Two reasons for reprogram:
	 *
	 * - The global event did not expire any CPU local
	 * events. This happens in dyntick mode, as the maximum PIT
	 * delta is quite small.
	 *
	 * - There are pending events on sleeping CPUs which were not
	 * in the event mask
	 */
	if (next_event.tv64 != KTIME_MAX) {
		/*
		 * Rearm the broadcast device. If event expired,
		 * repeat the above
		 */
		if (tick_broadcast_set_event(next_event, 0))
			goto again;
	}
	spin_unlock(&tick_broadcast_lock);
}

/*
 * Powerstate information: The system enters/leaves a state, where
 * affected devices might stop
 */
void tick_broadcast_oneshot_control(unsigned long reason)
{
	struct clock_event_device *bc, *dev;
	struct tick_device *td;
	unsigned long flags;
	int cpu;

	spin_lock_irqsave(&tick_broadcast_lock, flags);

	/*
	 * Periodic mode does not care about the enter/exit of power
	 * states
	 */
	if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC)
		goto out;

	bc = tick_broadcast_device.evtdev;
	cpu = smp_processor_id();
	td = &per_cpu(tick_cpu_device, cpu);
	dev = td->evtdev;

	if (!(dev->features & CLOCK_EVT_FEAT_C3STOP))
		goto out;

	if (reason == CLOCK_EVT_NOTIFY_BROADCAST_ENTER) {
		if (!cpu_isset(cpu, tick_broadcast_oneshot_mask)) {
			cpu_set(cpu, tick_broadcast_oneshot_mask);
			clockevents_set_mode(dev, CLOCK_EVT_MODE_SHUTDOWN);
			if (dev->next_event.tv64 < bc->next_event.tv64)
				tick_broadcast_set_event(dev->next_event, 1);
		}
	} else {
		if (cpu_isset(cpu, tick_broadcast_oneshot_mask)) {
			cpu_clear(cpu, tick_broadcast_oneshot_mask);
			clockevents_set_mode(dev, CLOCK_EVT_MODE_ONESHOT);
			if (dev->next_event.tv64 != KTIME_MAX)
				tick_program_event(dev->next_event, 1);
		}
	}

out:
	spin_unlock_irqrestore(&tick_broadcast_lock, flags);
}

/*
 * Reset the one shot broadcast for a cpu
 *
 * Called with tick_broadcast_lock held
 */
static void tick_broadcast_clear_oneshot(int cpu)
{
	cpu_clear(cpu, tick_broadcast_oneshot_mask);
}

/**
 * tick_broadcast_setup_oneshot - setup the broadcast device
 */
void tick_broadcast_setup_oneshot(struct clock_event_device *bc)
{
	bc->event_handler = tick_handle_oneshot_broadcast;
	clockevents_set_mode(bc, CLOCK_EVT_MODE_ONESHOT);
	bc->next_event.tv64 = KTIME_MAX;
}

/*
 * Select oneshot operating mode for the broadcast device
 */
void tick_broadcast_switch_to_oneshot(void)
{
	struct clock_event_device *bc;
	unsigned long flags;

	spin_lock_irqsave(&tick_broadcast_lock, flags);

	tick_broadcast_device.mode = TICKDEV_MODE_ONESHOT;
	bc = tick_broadcast_device.evtdev;
	if (bc)
		tick_broadcast_setup_oneshot(bc);
	spin_unlock_irqrestore(&tick_broadcast_lock, flags);
}


/*
 * Remove a dead CPU from broadcasting
 */
void tick_shutdown_broadcast_oneshot(unsigned int *cpup)
{
	unsigned long flags;
	unsigned int cpu = *cpup;

	spin_lock_irqsave(&tick_broadcast_lock, flags);

	/*
	 * Clear the broadcast mask flag for the dead cpu, but do not
	 * stop the broadcast device!
	 */
	cpu_clear(cpu, tick_broadcast_oneshot_mask);

	spin_unlock_irqrestore(&tick_broadcast_lock, flags);
}

#endif
Commit	Line	Data
f8381cba TG	1	/*
	2	* linux/kernel/time/tick-broadcast.c
	3	*
	4	* This file contains functions which emulate a local clock-event
	5	* device via a broadcast event source.
	6	*
	7	* Copyright(C) 2005-2006, Thomas Gleixner <tglx@linutronix.de>
	8	* Copyright(C) 2005-2007, Red Hat, Inc., Ingo Molnar
	9	* Copyright(C) 2006-2007, Timesys Corp., Thomas Gleixner
	10	*
	11	* This code is licenced under the GPL version 2. For details see
	12	* kernel-base/COPYING.
	13	*/
	14	#include <linux/cpu.h>
	15	#include <linux/err.h>
	16	#include <linux/hrtimer.h>
d7b90689	17	#include <linux/interrupt.h>
f8381cba TG	18	#include <linux/percpu.h>
	19	#include <linux/profile.h>
	20	#include <linux/sched.h>
	21	#include <linux/tick.h>
	22
	23	#include "tick-internal.h"
	24
	25	/*
	26	* Broadcast support for broken x86 hardware, where the local apic
	27	* timer stops in C3 state.
	28	*/
	29
	30	struct tick_device tick_broadcast_device;
	31	static cpumask_t tick_broadcast_mask;
79bf2bb3	32	static DEFINE_SPINLOCK(tick_broadcast_lock);
aa276e1c	33	static int tick_broadcast_force;
f8381cba	34
5590a536 TG	35	#ifdef CONFIG_TICK_ONESHOT
	36	static void tick_broadcast_clear_oneshot(int cpu);
	37	#else
	38	static inline void tick_broadcast_clear_oneshot(int cpu) { }
	39	#endif
	40
289f480a IM	41	/*
	42	* Debugging: see timer_list.c
	43	*/
	44	struct tick_device *tick_get_broadcast_device(void)
	45	{
	46	return &tick_broadcast_device;
	47	}
	48
	49	cpumask_t *tick_get_broadcast_mask(void)
	50	{
	51	return &tick_broadcast_mask;
	52	}
	53
f8381cba TG	54	/*
	55	* Start the device in periodic mode
	56	*/
	57	static void tick_broadcast_start_periodic(struct clock_event_device *bc)
	58	{
18de5bc4	59	if (bc)
f8381cba TG	60	tick_setup_periodic(bc, 1);
	61	}
	62
	63	/*
	64	* Check, if the device can be utilized as broadcast device:
	65	*/
	66	int tick_check_broadcast_device(struct clock_event_device *dev)
	67	{
4a93232d VP	68	if ((tick_broadcast_device.evtdev &&
	69	tick_broadcast_device.evtdev->rating >= dev->rating) \|\|
	70	(dev->features & CLOCK_EVT_FEAT_C3STOP))
f8381cba TG	71	return 0;
	72
	73	clockevents_exchange_device(NULL, dev);
	74	tick_broadcast_device.evtdev = dev;
	75	if (!cpus_empty(tick_broadcast_mask))
	76	tick_broadcast_start_periodic(dev);
	77	return 1;
	78	}
	79
	80	/*
	81	* Check, if the device is the broadcast device
	82	*/
	83	int tick_is_broadcast_device(struct clock_event_device *dev)
	84	{
	85	return (dev && tick_broadcast_device.evtdev == dev);
	86	}
	87
	88	/*
	89	* Check, if the device is disfunctional and a place holder, which
	90	* needs to be handled by the broadcast device.
	91	*/
	92	int tick_device_uses_broadcast(struct clock_event_device *dev, int cpu)
	93	{
	94	unsigned long flags;
	95	int ret = 0;
	96
	97	spin_lock_irqsave(&tick_broadcast_lock, flags);
	98
	99	/*
	100	* Devices might be registered with both periodic and oneshot
	101	* mode disabled. This signals, that the device needs to be
	102	* operated from the broadcast device and is a placeholder for
	103	* the cpu local device.
	104	*/
	105	if (!tick_device_is_functional(dev)) {
	106	dev->event_handler = tick_handle_periodic;
	107	cpu_set(cpu, tick_broadcast_mask);
	108	tick_broadcast_start_periodic(tick_broadcast_device.evtdev);
	109	ret = 1;
5590a536 TG	110	} else {
	111	/*
	112	* When the new device is not affected by the stop
	113	* feature and the cpu is marked in the broadcast mask
	114	* then clear the broadcast bit.
	115	*/
	116	if (!(dev->features & CLOCK_EVT_FEAT_C3STOP)) {
	117	int cpu = smp_processor_id();
f8381cba	118
5590a536 TG	119	cpu_clear(cpu, tick_broadcast_mask);
	120	tick_broadcast_clear_oneshot(cpu);
	121	}
	122	}
f8381cba TG	123	spin_unlock_irqrestore(&tick_broadcast_lock, flags);
	124	return ret;
	125	}
	126
	127	/*
	128	* Broadcast the event to the cpus, which are set in the mask
	129	*/
186e3cb8	130	static void tick_do_broadcast(cpumask_t mask)
f8381cba	131	{
186e3cb8	132	int cpu = smp_processor_id();
f8381cba TG	133	struct tick_device *td;
	134
	135	/*
	136	* Check, if the current cpu is in the mask
	137	*/
	138	if (cpu_isset(cpu, mask)) {
	139	cpu_clear(cpu, mask);
	140	td = &per_cpu(tick_cpu_device, cpu);
	141	td->evtdev->event_handler(td->evtdev);
f8381cba TG	142	}
	143
	144	if (!cpus_empty(mask)) {
	145	/*
	146	* It might be necessary to actually check whether the devices
	147	* have different broadcast functions. For now, just use the
	148	* one of the first device. This works as long as we have this
	149	* misfeature only on x86 (lapic)
	150	*/
	151	cpu = first_cpu(mask);
	152	td = &per_cpu(tick_cpu_device, cpu);
	153	td->evtdev->broadcast(mask);
f8381cba	154	}
f8381cba TG	155	}
	156
	157	/*
	158	* Periodic broadcast:
	159	* - invoke the broadcast handlers
	160	*/
	161	static void tick_do_periodic_broadcast(void)
	162	{
	163	cpumask_t mask;
	164
	165	spin_lock(&tick_broadcast_lock);
	166
	167	cpus_and(mask, cpu_online_map, tick_broadcast_mask);
	168	tick_do_broadcast(mask);
	169
	170	spin_unlock(&tick_broadcast_lock);
	171	}
	172
	173	/*
	174	* Event handler for periodic broadcast ticks
	175	*/
	176	static void tick_handle_periodic_broadcast(struct clock_event_device *dev)
	177	{
f8381cba TG	178	tick_do_periodic_broadcast();
	179
	180	/*
	181	* The device is in periodic mode. No reprogramming necessary:
	182	*/
	183	if (dev->mode == CLOCK_EVT_MODE_PERIODIC)
	184	return;
	185
	186	/*
	187	* Setup the next period for devices, which do not have
	188	* periodic mode:
	189	*/
	190	for (;;) {
	191	ktime_t next = ktime_add(dev->next_event, tick_period);
	192
	193	if (!clockevents_program_event(dev, next, ktime_get()))
	194	return;
	195	tick_do_periodic_broadcast();
	196	}
	197	}
	198
	199	/*
	200	* Powerstate information: The system enters/leaves a state, where
	201	* affected devices might stop
	202	*/
	203	static void tick_do_broadcast_on_off(void *why)
	204	{
	205	struct clock_event_device bc, dev;
	206	struct tick_device *td;
	207	unsigned long flags, *reason = why;
	208	int cpu;
	209
	210	spin_lock_irqsave(&tick_broadcast_lock, flags);
	211
	212	cpu = smp_processor_id();
	213	td = &per_cpu(tick_cpu_device, cpu);
	214	dev = td->evtdev;
	215	bc = tick_broadcast_device.evtdev;
	216
	217	/*
1595f452	218	* Is the device not affected by the powerstate ?
f8381cba	219	*/
1595f452	220	if (!dev \|\| !(dev->features & CLOCK_EVT_FEAT_C3STOP))
f8381cba TG	221	goto out;
f8381cba TG	222
3dfbc884 TG	223	if (!tick_device_is_functional(dev))
3dfbc884 TG	224	goto out;
1595f452 TG	225
	226	switch (*reason) {
	227	case CLOCK_EVT_NOTIFY_BROADCAST_ON:
	228	case CLOCK_EVT_NOTIFY_BROADCAST_FORCE:
f8381cba TG	229	if (!cpu_isset(cpu, tick_broadcast_mask)) {
	230	cpu_set(cpu, tick_broadcast_mask);
	231	if (td->mode == TICKDEV_MODE_PERIODIC)
	232	clockevents_set_mode(dev,
	233	CLOCK_EVT_MODE_SHUTDOWN);
	234	}
3dfbc884	235	if (*reason == CLOCK_EVT_NOTIFY_BROADCAST_FORCE)
aa276e1c	236	tick_broadcast_force = 1;
1595f452 TG	237	break;
1595f452 TG	238	case CLOCK_EVT_NOTIFY_BROADCAST_OFF:
aa276e1c TG	239	if (!tick_broadcast_force &&
aa276e1c TG	240	cpu_isset(cpu, tick_broadcast_mask)) {
f8381cba TG	241	cpu_clear(cpu, tick_broadcast_mask);
	242	if (td->mode == TICKDEV_MODE_PERIODIC)
	243	tick_setup_periodic(dev, 0);
	244	}
1595f452	245	break;
f8381cba TG	246	}
	247
	248	if (cpus_empty(tick_broadcast_mask))
	249	clockevents_set_mode(bc, CLOCK_EVT_MODE_SHUTDOWN);
	250	else {
	251	if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC)
	252	tick_broadcast_start_periodic(bc);
79bf2bb3 TG	253	else
79bf2bb3 TG	254	tick_broadcast_setup_oneshot(bc);
f8381cba TG	255	}
	256	out:
	257	spin_unlock_irqrestore(&tick_broadcast_lock, flags);
	258	}
	259
	260	/*
	261	* Powerstate information: The system enters/leaves a state, where
	262	* affected devices might stop.
	263	*/
	264	void tick_broadcast_on_off(unsigned long reason, int *oncpu)
	265	{
bf020cb7	266	if (!cpu_isset(*oncpu, cpu_online_map))
833df317	267	printk(KERN_ERR "tick-broadcast: ignoring broadcast for "
72fcde96	268	"offline CPU #%d\n", *oncpu);
bf020cb7 AK	269	else
	270	smp_call_function_single(*oncpu, tick_do_broadcast_on_off,
	271	&reason, 1, 1);
f8381cba TG	272	}
	273
	274	/*
	275	* Set the periodic handler depending on broadcast on/off
	276	*/
	277	void tick_set_periodic_handler(struct clock_event_device *dev, int broadcast)
	278	{
	279	if (!broadcast)
	280	dev->event_handler = tick_handle_periodic;
	281	else
	282	dev->event_handler = tick_handle_periodic_broadcast;
	283	}
	284
	285	/*
	286	* Remove a CPU from broadcasting
	287	*/
	288	void tick_shutdown_broadcast(unsigned int *cpup)
	289	{
	290	struct clock_event_device *bc;
	291	unsigned long flags;
	292	unsigned int cpu = *cpup;
	293
	294	spin_lock_irqsave(&tick_broadcast_lock, flags);
	295
	296	bc = tick_broadcast_device.evtdev;
	297	cpu_clear(cpu, tick_broadcast_mask);
	298
	299	if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC) {
	300	if (bc && cpus_empty(tick_broadcast_mask))
	301	clockevents_set_mode(bc, CLOCK_EVT_MODE_SHUTDOWN);
	302	}
	303
	304	spin_unlock_irqrestore(&tick_broadcast_lock, flags);
	305	}
79bf2bb3	306
6321dd60 TG	307	void tick_suspend_broadcast(void)
	308	{
	309	struct clock_event_device *bc;
	310	unsigned long flags;
	311
	312	spin_lock_irqsave(&tick_broadcast_lock, flags);
	313
	314	bc = tick_broadcast_device.evtdev;
18de5bc4	315	if (bc)
6321dd60 TG	316	clockevents_set_mode(bc, CLOCK_EVT_MODE_SHUTDOWN);
	317
	318	spin_unlock_irqrestore(&tick_broadcast_lock, flags);
	319	}
	320
	321	int tick_resume_broadcast(void)
	322	{
	323	struct clock_event_device *bc;
	324	unsigned long flags;
	325	int broadcast = 0;
	326
	327	spin_lock_irqsave(&tick_broadcast_lock, flags);
	328
	329	bc = tick_broadcast_device.evtdev;
6321dd60	330
cd05a1f8	331	if (bc) {
18de5bc4 TG	332	clockevents_set_mode(bc, CLOCK_EVT_MODE_RESUME);
18de5bc4 TG	333
cd05a1f8 TG	334	switch (tick_broadcast_device.mode) {
	335	case TICKDEV_MODE_PERIODIC:
	336	if(!cpus_empty(tick_broadcast_mask))
	337	tick_broadcast_start_periodic(bc);
	338	broadcast = cpu_isset(smp_processor_id(),
	339	tick_broadcast_mask);
	340	break;
	341	case TICKDEV_MODE_ONESHOT:
	342	broadcast = tick_resume_broadcast_oneshot(bc);
	343	break;
	344	}
6321dd60 TG	345	}
	346	spin_unlock_irqrestore(&tick_broadcast_lock, flags);
	347
	348	return broadcast;
	349	}
	350
	351
79bf2bb3 TG	352	#ifdef CONFIG_TICK_ONESHOT
	353
	354	static cpumask_t tick_broadcast_oneshot_mask;
	355
289f480a IM	356	/*
	357	* Debugging: see timer_list.c
	358	*/
	359	cpumask_t *tick_get_broadcast_oneshot_mask(void)
	360	{
	361	return &tick_broadcast_oneshot_mask;
	362	}
	363
79bf2bb3 TG	364	static int tick_broadcast_set_event(ktime_t expires, int force)
	365	{
	366	struct clock_event_device *bc = tick_broadcast_device.evtdev;
	367	ktime_t now = ktime_get();
	368	int res;
	369
	370	for(;;) {
	371	res = clockevents_program_event(bc, expires, now);
	372	if (!res \|\| !force)
	373	return res;
	374	now = ktime_get();
	375	expires = ktime_add(now, ktime_set(0, bc->min_delta_ns));
	376	}
	377	}
	378
cd05a1f8 TG	379	int tick_resume_broadcast_oneshot(struct clock_event_device *bc)
	380	{
	381	clockevents_set_mode(bc, CLOCK_EVT_MODE_ONESHOT);
b7e113dc	382	return 0;
cd05a1f8 TG	383	}
cd05a1f8 TG	384
79bf2bb3 TG	385	/*
	386	* Handle oneshot mode broadcasting
	387	*/
	388	static void tick_handle_oneshot_broadcast(struct clock_event_device *dev)
	389	{
	390	struct tick_device *td;
	391	cpumask_t mask;
cdc6f27d	392	ktime_t now, next_event;
79bf2bb3 TG	393	int cpu;
	394
	395	spin_lock(&tick_broadcast_lock);
	396	again:
	397	dev->next_event.tv64 = KTIME_MAX;
cdc6f27d	398	next_event.tv64 = KTIME_MAX;
79bf2bb3 TG	399	mask = CPU_MASK_NONE;
	400	now = ktime_get();
	401	/* Find all expired events */
	402	for (cpu = first_cpu(tick_broadcast_oneshot_mask); cpu != NR_CPUS;
	403	cpu = next_cpu(cpu, tick_broadcast_oneshot_mask)) {
	404	td = &per_cpu(tick_cpu_device, cpu);
	405	if (td->evtdev->next_event.tv64 <= now.tv64)
	406	cpu_set(cpu, mask);
cdc6f27d TG	407	else if (td->evtdev->next_event.tv64 < next_event.tv64)
cdc6f27d TG	408	next_event.tv64 = td->evtdev->next_event.tv64;
79bf2bb3 TG	409	}
	410
	411	/*
cdc6f27d TG	412	* Wakeup the cpus which have an expired event.
	413	*/
	414	tick_do_broadcast(mask);
	415
	416	/*
	417	* Two reasons for reprogram:
	418	*
	419	* - The global event did not expire any CPU local
	420	* events. This happens in dyntick mode, as the maximum PIT
	421	* delta is quite small.
	422	*
	423	* - There are pending events on sleeping CPUs which were not
	424	* in the event mask
79bf2bb3	425	*/
cdc6f27d	426	if (next_event.tv64 != KTIME_MAX) {
79bf2bb3	427	/*
cdc6f27d TG	428	* Rearm the broadcast device. If event expired,
cdc6f27d TG	429	* repeat the above
79bf2bb3	430	*/
cdc6f27d	431	if (tick_broadcast_set_event(next_event, 0))
79bf2bb3 TG	432	goto again;
	433	}
	434	spin_unlock(&tick_broadcast_lock);
	435	}
	436
	437	/*
	438	* Powerstate information: The system enters/leaves a state, where
	439	* affected devices might stop
	440	*/
	441	void tick_broadcast_oneshot_control(unsigned long reason)
	442	{
	443	struct clock_event_device bc, dev;
	444	struct tick_device *td;
	445	unsigned long flags;
	446	int cpu;
	447
	448	spin_lock_irqsave(&tick_broadcast_lock, flags);
	449
	450	/*
	451	* Periodic mode does not care about the enter/exit of power
	452	* states
	453	*/
	454	if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC)
	455	goto out;
	456
	457	bc = tick_broadcast_device.evtdev;
	458	cpu = smp_processor_id();
	459	td = &per_cpu(tick_cpu_device, cpu);
	460	dev = td->evtdev;
	461
	462	if (!(dev->features & CLOCK_EVT_FEAT_C3STOP))
	463	goto out;
	464
	465	if (reason == CLOCK_EVT_NOTIFY_BROADCAST_ENTER) {
	466	if (!cpu_isset(cpu, tick_broadcast_oneshot_mask)) {
	467	cpu_set(cpu, tick_broadcast_oneshot_mask);
	468	clockevents_set_mode(dev, CLOCK_EVT_MODE_SHUTDOWN);
	469	if (dev->next_event.tv64 < bc->next_event.tv64)
	470	tick_broadcast_set_event(dev->next_event, 1);
	471	}
	472	} else {
	473	if (cpu_isset(cpu, tick_broadcast_oneshot_mask)) {
	474	cpu_clear(cpu, tick_broadcast_oneshot_mask);
	475	clockevents_set_mode(dev, CLOCK_EVT_MODE_ONESHOT);
	476	if (dev->next_event.tv64 != KTIME_MAX)
	477	tick_program_event(dev->next_event, 1);
	478	}
	479	}
	480
	481	out:
	482	spin_unlock_irqrestore(&tick_broadcast_lock, flags);
	483	}
	484
5590a536 TG	485	/*
	486	* Reset the one shot broadcast for a cpu
	487	*
	488	* Called with tick_broadcast_lock held
	489	*/
	490	static void tick_broadcast_clear_oneshot(int cpu)
	491	{
	492	cpu_clear(cpu, tick_broadcast_oneshot_mask);
	493	}
	494
79bf2bb3	495	/**
8dce39c2	496	* tick_broadcast_setup_oneshot - setup the broadcast device
79bf2bb3 TG	497	*/
	498	void tick_broadcast_setup_oneshot(struct clock_event_device *bc)
	499	{
4a93232d VP	500	bc->event_handler = tick_handle_oneshot_broadcast;
	501	clockevents_set_mode(bc, CLOCK_EVT_MODE_ONESHOT);
	502	bc->next_event.tv64 = KTIME_MAX;
79bf2bb3 TG	503	}
	504
	505	/*
	506	* Select oneshot operating mode for the broadcast device
	507	*/
	508	void tick_broadcast_switch_to_oneshot(void)
	509	{
	510	struct clock_event_device *bc;
	511	unsigned long flags;
	512
	513	spin_lock_irqsave(&tick_broadcast_lock, flags);
	514
	515	tick_broadcast_device.mode = TICKDEV_MODE_ONESHOT;
	516	bc = tick_broadcast_device.evtdev;
	517	if (bc)
	518	tick_broadcast_setup_oneshot(bc);
	519	spin_unlock_irqrestore(&tick_broadcast_lock, flags);
	520	}
	521
	522
	523	/*
	524	* Remove a dead CPU from broadcasting
	525	*/
	526	void tick_shutdown_broadcast_oneshot(unsigned int *cpup)
	527	{
79bf2bb3 TG	528	unsigned long flags;
	529	unsigned int cpu = *cpup;
	530
	531	spin_lock_irqsave(&tick_broadcast_lock, flags);
	532
31d9b393 TG	533	/*
	534	* Clear the broadcast mask flag for the dead cpu, but do not
	535	* stop the broadcast device!
	536	*/
79bf2bb3 TG	537	cpu_clear(cpu, tick_broadcast_oneshot_mask);
79bf2bb3 TG	538
79bf2bb3 TG	539	spin_unlock_irqrestore(&tick_broadcast_lock, flags);
	540	}
	541
	542	#endif