[GitHub/mt8127/android_kernel_alcatel_ttab.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/irq.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);

/*
 * Start the device in periodic mode
 */
static void tick_broadcast_start_periodic(struct clock_event_device *bc)
{
	if (bc && bc->mode == CLOCK_EVT_MODE_SHUTDOWN)
		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 ||
	    (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;
	}

	spin_unlock_irqrestore(&tick_broadcast_lock, flags);
	return ret;
}

/*
 * Broadcast the event to the cpus, which are set in the mask
 */
int tick_do_broadcast(cpumask_t mask)
{
	int ret = 0, 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);
		ret = 1;
	}

	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);
		ret = 1;
	}
	return ret;
}

/*
 * 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)
{
	dev->next_event.tv64 = KTIME_MAX;

	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 in broadcast mode forever or is it not
	 * affected by the powerstate ?
	 */
	if (!dev || !tick_device_is_functional(dev) ||
	    !(dev->features & CLOCK_EVT_FEAT_C3STOP))
		goto out;

	if (*reason == CLOCK_EVT_NOTIFY_BROADCAST_ON) {
		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);
		}
	} else {
		if (cpu_isset(cpu, tick_broadcast_mask)) {
			cpu_clear(cpu, tick_broadcast_mask);
			if (td->mode == TICKDEV_MODE_PERIODIC)
				tick_setup_periodic(dev, 0);
		}
	}

	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)
{
	int cpu = get_cpu();

	if (cpu == *oncpu)
		tick_do_broadcast_on_off(&reason);
	else
		smp_call_function_single(*oncpu, tick_do_broadcast_on_off,
					 &reason, 1, 1);
	put_cpu();
}

/*
 * 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);
}

#ifdef CONFIG_TICK_ONESHOT

static cpumask_t 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));
	}
}

/*
 * Reprogram the broadcast device:
 *
 * Called with tick_broadcast_lock held and interrupts disabled.
 */
static int tick_broadcast_reprogram(void)
{
	ktime_t expires = { .tv64 = KTIME_MAX };
	struct tick_device *td;
	int cpu;

	/*
	 * Find the event which expires next:
	 */
	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 < expires.tv64)
			expires = td->evtdev->next_event;
	}

	if (expires.tv64 == KTIME_MAX)
		return 0;

	return tick_broadcast_set_event(expires, 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;
	int cpu;

	spin_lock(&tick_broadcast_lock);
again:
	dev->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);
	}

	/*
	 * Wakeup the cpus which have an expired event. The broadcast
	 * device is reprogrammed in the return from idle code.
	 */
	if (!tick_do_broadcast(mask)) {
		/*
		 * The global event did not expire any CPU local
		 * events. This happens in dyntick mode, as the
		 * maximum PIT delta is quite small.
		 */
		if (tick_broadcast_reprogram())
			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);
}

/**
 * tick_broadcast_setup_highres - setup the broadcast device for highres
 */
void tick_broadcast_setup_oneshot(struct clock_event_device *bc)
{
	if (bc->mode != CLOCK_EVT_MODE_ONESHOT) {
		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)
{
	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_oneshot_mask);

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

	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>
	17	#include <linux/irq.h>
	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);
f8381cba TG	33
	34	/*
	35	* Start the device in periodic mode
	36	*/
	37	static void tick_broadcast_start_periodic(struct clock_event_device *bc)
	38	{
	39	if (bc && bc->mode == CLOCK_EVT_MODE_SHUTDOWN)
	40	tick_setup_periodic(bc, 1);
	41	}
	42
	43	/*
	44	* Check, if the device can be utilized as broadcast device:
	45	*/
	46	int tick_check_broadcast_device(struct clock_event_device *dev)
	47	{
	48	if (tick_broadcast_device.evtdev \|\|
	49	(dev->features & CLOCK_EVT_FEAT_C3STOP))
	50	return 0;
	51
	52	clockevents_exchange_device(NULL, dev);
	53	tick_broadcast_device.evtdev = dev;
	54	if (!cpus_empty(tick_broadcast_mask))
	55	tick_broadcast_start_periodic(dev);
	56	return 1;
	57	}
	58
	59	/*
	60	* Check, if the device is the broadcast device
	61	*/
	62	int tick_is_broadcast_device(struct clock_event_device *dev)
	63	{
	64	return (dev && tick_broadcast_device.evtdev == dev);
	65	}
	66
	67	/*
	68	* Check, if the device is disfunctional and a place holder, which
	69	* needs to be handled by the broadcast device.
	70	*/
	71	int tick_device_uses_broadcast(struct clock_event_device *dev, int cpu)
	72	{
	73	unsigned long flags;
	74	int ret = 0;
	75
	76	spin_lock_irqsave(&tick_broadcast_lock, flags);
	77
	78	/*
	79	* Devices might be registered with both periodic and oneshot
	80	* mode disabled. This signals, that the device needs to be
	81	* operated from the broadcast device and is a placeholder for
	82	* the cpu local device.
	83	*/
	84	if (!tick_device_is_functional(dev)) {
	85	dev->event_handler = tick_handle_periodic;
	86	cpu_set(cpu, tick_broadcast_mask);
	87	tick_broadcast_start_periodic(tick_broadcast_device.evtdev);
	88	ret = 1;
	89	}
	90
	91	spin_unlock_irqrestore(&tick_broadcast_lock, flags);
	92	return ret;
	93	}
	94
	95	/*
	96	* Broadcast the event to the cpus, which are set in the mask
97	*/
98	int tick_do_broadcast(cpumask_t mask)
99	{
100	int ret = 0, cpu = smp_processor_id();
101	struct tick_device *td;
102
103	/*
104	* Check, if the current cpu is in the mask
105	*/
106	if (cpu_isset(cpu, mask)) {
107	cpu_clear(cpu, mask);
108	td = &per_cpu(tick_cpu_device, cpu);
109	td->evtdev->event_handler(td->evtdev);
110	ret = 1;
111	}
112
113	if (!cpus_empty(mask)) {
114	/*
115	* It might be necessary to actually check whether the devices
116	* have different broadcast functions. For now, just use the
117	* one of the first device. This works as long as we have this
118	* misfeature only on x86 (lapic)
119	*/
120	cpu = first_cpu(mask);
121	td = &per_cpu(tick_cpu_device, cpu);
122	td->evtdev->broadcast(mask);
123	ret = 1;
124	}
125	return ret;
126	}
127
128	/*
129	* Periodic broadcast:
130	* - invoke the broadcast handlers
131	*/
132	static void tick_do_periodic_broadcast(void)
133	{
134	cpumask_t mask;
135
136	spin_lock(&tick_broadcast_lock);
137
138	cpus_and(mask, cpu_online_map, tick_broadcast_mask);
139	tick_do_broadcast(mask);
140
141	spin_unlock(&tick_broadcast_lock);
142	}
143
144	/*
145	* Event handler for periodic broadcast ticks
146	*/
147	static void tick_handle_periodic_broadcast(struct clock_event_device *dev)
148	{
149	dev->next_event.tv64 = KTIME_MAX;
150
151	tick_do_periodic_broadcast();
152
153	/*
154	* The device is in periodic mode. No reprogramming necessary:
155	*/
156	if (dev->mode == CLOCK_EVT_MODE_PERIODIC)
157	return;
158
159	/*
160	* Setup the next period for devices, which do not have
161	* periodic mode:
162	*/
163	for (;;) {
164	ktime_t next = ktime_add(dev->next_event, tick_period);
165
166	if (!clockevents_program_event(dev, next, ktime_get()))
167	return;
168	tick_do_periodic_broadcast();
169	}
170	}
171
172	/*
173	* Powerstate information: The system enters/leaves a state, where
174	* affected devices might stop
175	*/
176	static void tick_do_broadcast_on_off(void *why)
177	{
178	struct clock_event_device bc, dev;
179	struct tick_device *td;
180	unsigned long flags, *reason = why;
181	int cpu;
182
183	spin_lock_irqsave(&tick_broadcast_lock, flags);
184
185	cpu = smp_processor_id();
186	td = &per_cpu(tick_cpu_device, cpu);
187	dev = td->evtdev;
188	bc = tick_broadcast_device.evtdev;
189
190	/*
191	* Is the device in broadcast mode forever or is it not
192	* affected by the powerstate ?
193	*/
194	if (!dev \|\| !tick_device_is_functional(dev) \|\|
195	!(dev->features & CLOCK_EVT_FEAT_C3STOP))
196	goto out;
197
198	if (*reason == CLOCK_EVT_NOTIFY_BROADCAST_ON) {
199	if (!cpu_isset(cpu, tick_broadcast_mask)) {
200	cpu_set(cpu, tick_broadcast_mask);
201	if (td->mode == TICKDEV_MODE_PERIODIC)
202	clockevents_set_mode(dev,
203	CLOCK_EVT_MODE_SHUTDOWN);
204	}
205	} else {
206	if (cpu_isset(cpu, tick_broadcast_mask)) {
207	cpu_clear(cpu, tick_broadcast_mask);
208	if (td->mode == TICKDEV_MODE_PERIODIC)
209	tick_setup_periodic(dev, 0);
210	}
211	}
212
213	if (cpus_empty(tick_broadcast_mask))
214	clockevents_set_mode(bc, CLOCK_EVT_MODE_SHUTDOWN);
215	else {
216	if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC)
217	tick_broadcast_start_periodic(bc);
79bf2bb3 TG	218	else
79bf2bb3 TG	219	tick_broadcast_setup_oneshot(bc);
f8381cba TG	220	}
	221	out:
	222	spin_unlock_irqrestore(&tick_broadcast_lock, flags);
	223	}
	224
	225	/*
	226	* Powerstate information: The system enters/leaves a state, where
	227	* affected devices might stop.
	228	*/
	229	void tick_broadcast_on_off(unsigned long reason, int *oncpu)
	230	{
	231	int cpu = get_cpu();
	232
	233	if (cpu == *oncpu)
	234	tick_do_broadcast_on_off(&reason);
	235	else
	236	smp_call_function_single(*oncpu, tick_do_broadcast_on_off,
	237	&reason, 1, 1);
	238	put_cpu();
	239	}
	240
	241	/*
	242	* Set the periodic handler depending on broadcast on/off
	243	*/
	244	void tick_set_periodic_handler(struct clock_event_device *dev, int broadcast)
	245	{
	246	if (!broadcast)
	247	dev->event_handler = tick_handle_periodic;
	248	else
	249	dev->event_handler = tick_handle_periodic_broadcast;
	250	}
	251
	252	/*
	253	* Remove a CPU from broadcasting
	254	*/
	255	void tick_shutdown_broadcast(unsigned int *cpup)
	256	{
	257	struct clock_event_device *bc;
	258	unsigned long flags;
	259	unsigned int cpu = *cpup;
	260
	261	spin_lock_irqsave(&tick_broadcast_lock, flags);
	262
	263	bc = tick_broadcast_device.evtdev;
	264	cpu_clear(cpu, tick_broadcast_mask);
	265
	266	if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC) {
	267	if (bc && cpus_empty(tick_broadcast_mask))
	268	clockevents_set_mode(bc, CLOCK_EVT_MODE_SHUTDOWN);
	269	}
	270
	271	spin_unlock_irqrestore(&tick_broadcast_lock, flags);
	272	}
79bf2bb3 TG	273
	274	#ifdef CONFIG_TICK_ONESHOT
	275
	276	static cpumask_t tick_broadcast_oneshot_mask;
	277
	278	static int tick_broadcast_set_event(ktime_t expires, int force)
	279	{
	280	struct clock_event_device *bc = tick_broadcast_device.evtdev;
	281	ktime_t now = ktime_get();
	282	int res;
	283
	284	for(;;) {
	285	res = clockevents_program_event(bc, expires, now);
	286	if (!res \|\| !force)
	287	return res;
	288	now = ktime_get();
	289	expires = ktime_add(now, ktime_set(0, bc->min_delta_ns));
	290	}
	291	}
	292
	293	/*
	294	* Reprogram the broadcast device:
	295	*
	296	* Called with tick_broadcast_lock held and interrupts disabled.
	297	*/
	298	static int tick_broadcast_reprogram(void)
	299	{
	300	ktime_t expires = { .tv64 = KTIME_MAX };
	301	struct tick_device *td;
	302	int cpu;
	303
	304	/*
	305	* Find the event which expires next:
	306	*/
	307	for (cpu = first_cpu(tick_broadcast_oneshot_mask); cpu != NR_CPUS;
	308	cpu = next_cpu(cpu, tick_broadcast_oneshot_mask)) {
	309	td = &per_cpu(tick_cpu_device, cpu);
	310	if (td->evtdev->next_event.tv64 < expires.tv64)
	311	expires = td->evtdev->next_event;
	312	}
	313
	314	if (expires.tv64 == KTIME_MAX)
	315	return 0;
	316
	317	return tick_broadcast_set_event(expires, 0);
	318	}
	319
	320	/*
	321	* Handle oneshot mode broadcasting
	322	*/
	323	static void tick_handle_oneshot_broadcast(struct clock_event_device *dev)
	324	{
	325	struct tick_device *td;
	326	cpumask_t mask;
	327	ktime_t now;
	328	int cpu;
	329
	330	spin_lock(&tick_broadcast_lock);
	331	again:
	332	dev->next_event.tv64 = KTIME_MAX;
	333	mask = CPU_MASK_NONE;
	334	now = ktime_get();
	335	/* Find all expired events */
	336	for (cpu = first_cpu(tick_broadcast_oneshot_mask); cpu != NR_CPUS;
337	cpu = next_cpu(cpu, tick_broadcast_oneshot_mask)) {
338	td = &per_cpu(tick_cpu_device, cpu);
339	if (td->evtdev->next_event.tv64 <= now.tv64)
340	cpu_set(cpu, mask);
341	}
342
343	/*
344	* Wakeup the cpus which have an expired event. The broadcast
345	* device is reprogrammed in the return from idle code.
346	*/
347	if (!tick_do_broadcast(mask)) {
348	/*
349	* The global event did not expire any CPU local
350	* events. This happens in dyntick mode, as the
351	* maximum PIT delta is quite small.
352	*/
353	if (tick_broadcast_reprogram())
354	goto again;
355	}
356	spin_unlock(&tick_broadcast_lock);
357	}
358
359	/*
360	* Powerstate information: The system enters/leaves a state, where
361	* affected devices might stop
362	*/
363	void tick_broadcast_oneshot_control(unsigned long reason)
364	{
365	struct clock_event_device bc, dev;
366	struct tick_device *td;
367	unsigned long flags;
368	int cpu;
369
370	spin_lock_irqsave(&tick_broadcast_lock, flags);
371
372	/*
373	* Periodic mode does not care about the enter/exit of power
374	* states
375	*/
376	if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC)
377	goto out;
378
379	bc = tick_broadcast_device.evtdev;
380	cpu = smp_processor_id();
381	td = &per_cpu(tick_cpu_device, cpu);
382	dev = td->evtdev;
383
384	if (!(dev->features & CLOCK_EVT_FEAT_C3STOP))
385	goto out;
386
387	if (reason == CLOCK_EVT_NOTIFY_BROADCAST_ENTER) {
388	if (!cpu_isset(cpu, tick_broadcast_oneshot_mask)) {
389	cpu_set(cpu, tick_broadcast_oneshot_mask);
390	clockevents_set_mode(dev, CLOCK_EVT_MODE_SHUTDOWN);
391	if (dev->next_event.tv64 < bc->next_event.tv64)
392	tick_broadcast_set_event(dev->next_event, 1);
393	}
394	} else {
395	if (cpu_isset(cpu, tick_broadcast_oneshot_mask)) {
396	cpu_clear(cpu, tick_broadcast_oneshot_mask);
397	clockevents_set_mode(dev, CLOCK_EVT_MODE_ONESHOT);
398	if (dev->next_event.tv64 != KTIME_MAX)
399	tick_program_event(dev->next_event, 1);
400	}
401	}
402
403	out:
404	spin_unlock_irqrestore(&tick_broadcast_lock, flags);
405	}
406
407	/**
408	* tick_broadcast_setup_highres - setup the broadcast device for highres
409	*/
410	void tick_broadcast_setup_oneshot(struct clock_event_device *bc)
411	{
412	if (bc->mode != CLOCK_EVT_MODE_ONESHOT) {
413	bc->event_handler = tick_handle_oneshot_broadcast;
414	clockevents_set_mode(bc, CLOCK_EVT_MODE_ONESHOT);
415	bc->next_event.tv64 = KTIME_MAX;
416	}
417	}
418
419	/*
420	* Select oneshot operating mode for the broadcast device
421	*/
422	void tick_broadcast_switch_to_oneshot(void)
423	{
424	struct clock_event_device *bc;
425	unsigned long flags;
426
427	spin_lock_irqsave(&tick_broadcast_lock, flags);
428
429	tick_broadcast_device.mode = TICKDEV_MODE_ONESHOT;
430	bc = tick_broadcast_device.evtdev;
431	if (bc)
432	tick_broadcast_setup_oneshot(bc);
433	spin_unlock_irqrestore(&tick_broadcast_lock, flags);
434	}
435
436
437	/*
438	* Remove a dead CPU from broadcasting
439	*/
440	void tick_shutdown_broadcast_oneshot(unsigned int *cpup)
441	{
442	struct clock_event_device *bc;
443	unsigned long flags;
444	unsigned int cpu = *cpup;
445
446	spin_lock_irqsave(&tick_broadcast_lock, flags);
447
448	bc = tick_broadcast_device.evtdev;
449	cpu_clear(cpu, tick_broadcast_oneshot_mask);
450
451	if (tick_broadcast_device.mode == TICKDEV_MODE_ONESHOT) {
452	if (bc && cpus_empty(tick_broadcast_oneshot_mask))
453	clockevents_set_mode(bc, CLOCK_EVT_MODE_SHUTDOWN);
454	}
455
456	spin_unlock_irqrestore(&tick_broadcast_lock, flags);
457	}
458
459	#endif