[mirror_ubuntu-bionic-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);

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