kernel/time/tick-broadcast.c - maze/linux - Git at Google

 /*
  * 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);

 /*
  * 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 && 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_isset(*oncpu, cpu_online_map)) {
 		printk(KERN_ERR "tick-braodcast: ignoring broadcast for "
 		       "offline CPU #%d\n", *oncpu);
 	} else {

 		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);
 }

 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 && tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC)
 		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) {
 		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);

 	if(!cpus_empty(tick_broadcast_oneshot_mask))
 		tick_broadcast_set_event(ktime_get(), 1);

 	return cpu_isset(smp_processor_id(), tick_broadcast_oneshot_mask);
 }

 /*
  * 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
	/*
	* 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);

	/*
	* 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 && 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_isset(*oncpu, cpu_online_map)) {
	printk(KERN_ERR "tick-braodcast: ignoring broadcast for "
	"offline CPU #%d\n", *oncpu);
	} else {

	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);
	}

	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 && tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC)
	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) {
	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);

	if(!cpus_empty(tick_broadcast_oneshot_mask))
	tick_broadcast_set_event(ktime_get(), 1);

	return cpu_isset(smp_processor_id(), tick_broadcast_oneshot_mask);
	}

	/*
	* 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