[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);
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)
{
	ktime_t next;

	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. We read dev->next_event first and add to it
	 * when the event alrady expired. clockevents_program_event()
	 * sets dev->next_event only when the event is really
	 * programmed to the device.
	 */
	for (next = dev->next_event; ;) {
		next = ktime_add(next, 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, bc_stopped;

	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;

	bc_stopped = cpus_empty(tick_broadcast_mask);

	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)) {
		if (!bc_stopped)
			clockevents_set_mode(bc, CLOCK_EVT_MODE_SHUTDOWN);
	} else if (bc_stopped) {
		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);
}

/*
 * 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;

	return tick_dev_program_event(bc, expires, force);
}

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_each_cpu_mask_nr(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);
}

static void tick_broadcast_init_next_event(cpumask_t *mask, ktime_t expires)
{
	struct tick_device *td;
	int cpu;

	for_each_cpu_mask_nr(cpu, *mask) {
		td = &per_cpu(tick_cpu_device, cpu);
		if (td->evtdev)
			td->evtdev->next_event = expires;
	}
}

/**
 * tick_broadcast_setup_oneshot - setup the broadcast device
 */
void tick_broadcast_setup_oneshot(struct clock_event_device *bc)
{
	/* Set it up only once ! */
	if (bc->event_handler != tick_handle_oneshot_broadcast) {
		int was_periodic = bc->mode == CLOCK_EVT_MODE_PERIODIC;
		int cpu = smp_processor_id();
		cpumask_t mask;

		bc->event_handler = tick_handle_oneshot_broadcast;
		clockevents_set_mode(bc, CLOCK_EVT_MODE_ONESHOT);

		/* Take the do_timer update */
		tick_do_timer_cpu = cpu;

		/*
		 * We must be careful here. There might be other CPUs
		 * waiting for periodic broadcast. We need to set the
		 * oneshot_mask bits for those and program the
		 * broadcast device to fire.
		 */
		mask = tick_broadcast_mask;
		cpu_clear(cpu, mask);
		cpus_or(tick_broadcast_oneshot_mask,
			tick_broadcast_oneshot_mask, mask);

		if (was_periodic && !cpus_empty(mask)) {
			tick_broadcast_init_next_event(&mask, tick_next_period);
			tick_broadcast_set_event(tick_next_period, 1);
		} else
			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	{
d4496b39 TG	178	ktime_t next;
d4496b39 TG	179
f8381cba TG	180	tick_do_periodic_broadcast();
	181
	182	/*
	183	* The device is in periodic mode. No reprogramming necessary:
	184	*/
	185	if (dev->mode == CLOCK_EVT_MODE_PERIODIC)
	186	return;
	187
	188	/*
	189	* Setup the next period for devices, which do not have
d4496b39 TG	190	* periodic mode. We read dev->next_event first and add to it
	191	* when the event alrady expired. clockevents_program_event()
	192	* sets dev->next_event only when the event is really
	193	* programmed to the device.
f8381cba	194	*/
d4496b39 TG	195	for (next = dev->next_event; ;) {
d4496b39 TG	196	next = ktime_add(next, tick_period);
f8381cba TG	197
	198	if (!clockevents_program_event(dev, next, ktime_get()))
	199	return;
	200	tick_do_periodic_broadcast();
	201	}
	202	}
	203
	204	/*
	205	* Powerstate information: The system enters/leaves a state, where
	206	* affected devices might stop
	207	*/
	208	static void tick_do_broadcast_on_off(void *why)
	209	{
	210	struct clock_event_device bc, dev;
	211	struct tick_device *td;
	212	unsigned long flags, *reason = why;
9c17bcda	213	int cpu, bc_stopped;
f8381cba TG	214
	215	spin_lock_irqsave(&tick_broadcast_lock, flags);
	216
	217	cpu = smp_processor_id();
	218	td = &per_cpu(tick_cpu_device, cpu);
	219	dev = td->evtdev;
	220	bc = tick_broadcast_device.evtdev;
	221
	222	/*
1595f452	223	* Is the device not affected by the powerstate ?
f8381cba	224	*/
1595f452	225	if (!dev \|\| !(dev->features & CLOCK_EVT_FEAT_C3STOP))
f8381cba TG	226	goto out;
f8381cba TG	227
3dfbc884 TG	228	if (!tick_device_is_functional(dev))
3dfbc884 TG	229	goto out;
1595f452	230
9c17bcda TG	231	bc_stopped = cpus_empty(tick_broadcast_mask);
9c17bcda TG	232
1595f452 TG	233	switch (*reason) {
	234	case CLOCK_EVT_NOTIFY_BROADCAST_ON:
	235	case CLOCK_EVT_NOTIFY_BROADCAST_FORCE:
f8381cba TG	236	if (!cpu_isset(cpu, tick_broadcast_mask)) {
	237	cpu_set(cpu, tick_broadcast_mask);
	238	if (td->mode == TICKDEV_MODE_PERIODIC)
	239	clockevents_set_mode(dev,
	240	CLOCK_EVT_MODE_SHUTDOWN);
	241	}
3dfbc884	242	if (*reason == CLOCK_EVT_NOTIFY_BROADCAST_FORCE)
aa276e1c	243	tick_broadcast_force = 1;
1595f452 TG	244	break;
1595f452 TG	245	case CLOCK_EVT_NOTIFY_BROADCAST_OFF:
aa276e1c TG	246	if (!tick_broadcast_force &&
aa276e1c TG	247	cpu_isset(cpu, tick_broadcast_mask)) {
f8381cba TG	248	cpu_clear(cpu, tick_broadcast_mask);
	249	if (td->mode == TICKDEV_MODE_PERIODIC)
	250	tick_setup_periodic(dev, 0);
	251	}
1595f452	252	break;
f8381cba TG	253	}
f8381cba TG	254
9c17bcda TG	255	if (cpus_empty(tick_broadcast_mask)) {
	256	if (!bc_stopped)
	257	clockevents_set_mode(bc, CLOCK_EVT_MODE_SHUTDOWN);
	258	} else if (bc_stopped) {
f8381cba TG	259	if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC)
f8381cba TG	260	tick_broadcast_start_periodic(bc);
79bf2bb3 TG	261	else
79bf2bb3 TG	262	tick_broadcast_setup_oneshot(bc);
f8381cba TG	263	}
	264	out:
	265	spin_unlock_irqrestore(&tick_broadcast_lock, flags);
	266	}
	267
	268	/*
	269	* Powerstate information: The system enters/leaves a state, where
	270	* affected devices might stop.
	271	*/
	272	void tick_broadcast_on_off(unsigned long reason, int *oncpu)
	273	{
bf020cb7	274	if (!cpu_isset(*oncpu, cpu_online_map))
833df317	275	printk(KERN_ERR "tick-broadcast: ignoring broadcast for "
72fcde96	276	"offline CPU #%d\n", *oncpu);
bf020cb7 AK	277	else
bf020cb7 AK	278	smp_call_function_single(*oncpu, tick_do_broadcast_on_off,
8691e5a8	279	&reason, 1);
f8381cba TG	280	}
	281
	282	/*
	283	* Set the periodic handler depending on broadcast on/off
	284	*/
	285	void tick_set_periodic_handler(struct clock_event_device *dev, int broadcast)
	286	{
	287	if (!broadcast)
	288	dev->event_handler = tick_handle_periodic;
	289	else
	290	dev->event_handler = tick_handle_periodic_broadcast;
	291	}
	292
	293	/*
	294	* Remove a CPU from broadcasting
	295	*/
	296	void tick_shutdown_broadcast(unsigned int *cpup)
	297	{
	298	struct clock_event_device *bc;
	299	unsigned long flags;
	300	unsigned int cpu = *cpup;
	301
	302	spin_lock_irqsave(&tick_broadcast_lock, flags);
	303
	304	bc = tick_broadcast_device.evtdev;
	305	cpu_clear(cpu, tick_broadcast_mask);
	306
	307	if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC) {
	308	if (bc && cpus_empty(tick_broadcast_mask))
	309	clockevents_set_mode(bc, CLOCK_EVT_MODE_SHUTDOWN);
	310	}
	311
	312	spin_unlock_irqrestore(&tick_broadcast_lock, flags);
	313	}
79bf2bb3	314
6321dd60 TG	315	void tick_suspend_broadcast(void)
	316	{
	317	struct clock_event_device *bc;
	318	unsigned long flags;
	319
	320	spin_lock_irqsave(&tick_broadcast_lock, flags);
	321
	322	bc = tick_broadcast_device.evtdev;
18de5bc4	323	if (bc)
6321dd60 TG	324	clockevents_set_mode(bc, CLOCK_EVT_MODE_SHUTDOWN);
	325
	326	spin_unlock_irqrestore(&tick_broadcast_lock, flags);
	327	}
	328
	329	int tick_resume_broadcast(void)
	330	{
	331	struct clock_event_device *bc;
	332	unsigned long flags;
	333	int broadcast = 0;
	334
	335	spin_lock_irqsave(&tick_broadcast_lock, flags);
	336
	337	bc = tick_broadcast_device.evtdev;
6321dd60	338
cd05a1f8	339	if (bc) {
18de5bc4 TG	340	clockevents_set_mode(bc, CLOCK_EVT_MODE_RESUME);
18de5bc4 TG	341
cd05a1f8 TG	342	switch (tick_broadcast_device.mode) {
	343	case TICKDEV_MODE_PERIODIC:
	344	if(!cpus_empty(tick_broadcast_mask))
	345	tick_broadcast_start_periodic(bc);
	346	broadcast = cpu_isset(smp_processor_id(),
	347	tick_broadcast_mask);
	348	break;
	349	case TICKDEV_MODE_ONESHOT:
	350	broadcast = tick_resume_broadcast_oneshot(bc);
	351	break;
	352	}
6321dd60 TG	353	}
	354	spin_unlock_irqrestore(&tick_broadcast_lock, flags);
	355
	356	return broadcast;
	357	}
	358
	359
79bf2bb3 TG	360	#ifdef CONFIG_TICK_ONESHOT
	361
	362	static cpumask_t tick_broadcast_oneshot_mask;
	363
289f480a IM	364	/*
	365	* Debugging: see timer_list.c
	366	*/
	367	cpumask_t *tick_get_broadcast_oneshot_mask(void)
	368	{
	369	return &tick_broadcast_oneshot_mask;
	370	}
	371
79bf2bb3 TG	372	static int tick_broadcast_set_event(ktime_t expires, int force)
	373	{
	374	struct clock_event_device *bc = tick_broadcast_device.evtdev;
1fb9b7d2 TG	375
1fb9b7d2 TG	376	return tick_dev_program_event(bc, expires, force);
79bf2bb3 TG	377	}
79bf2bb3 TG	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 */
cad0e458	402	for_each_cpu_mask_nr(cpu, tick_broadcast_oneshot_mask) {
79bf2bb3 TG	403	td = &per_cpu(tick_cpu_device, cpu);
	404	if (td->evtdev->next_event.tv64 <= now.tv64)
	405	cpu_set(cpu, mask);
cdc6f27d TG	406	else if (td->evtdev->next_event.tv64 < next_event.tv64)
cdc6f27d TG	407	next_event.tv64 = td->evtdev->next_event.tv64;
79bf2bb3 TG	408	}
	409
	410	/*
cdc6f27d TG	411	* Wakeup the cpus which have an expired event.
	412	*/
	413	tick_do_broadcast(mask);
	414
	415	/*
	416	* Two reasons for reprogram:
	417	*
	418	* - The global event did not expire any CPU local
	419	* events. This happens in dyntick mode, as the maximum PIT
	420	* delta is quite small.
	421	*
	422	* - There are pending events on sleeping CPUs which were not
	423	* in the event mask
79bf2bb3	424	*/
cdc6f27d	425	if (next_event.tv64 != KTIME_MAX) {
79bf2bb3	426	/*
cdc6f27d TG	427	* Rearm the broadcast device. If event expired,
cdc6f27d TG	428	* repeat the above
79bf2bb3	429	*/
cdc6f27d	430	if (tick_broadcast_set_event(next_event, 0))
79bf2bb3 TG	431	goto again;
	432	}
	433	spin_unlock(&tick_broadcast_lock);
	434	}
	435
	436	/*
	437	* Powerstate information: The system enters/leaves a state, where
	438	* affected devices might stop
	439	*/
	440	void tick_broadcast_oneshot_control(unsigned long reason)
	441	{
	442	struct clock_event_device bc, dev;
	443	struct tick_device *td;
	444	unsigned long flags;
	445	int cpu;
	446
	447	spin_lock_irqsave(&tick_broadcast_lock, flags);
	448
	449	/*
	450	* Periodic mode does not care about the enter/exit of power
	451	* states
	452	*/
	453	if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC)
	454	goto out;
	455
	456	bc = tick_broadcast_device.evtdev;
	457	cpu = smp_processor_id();
	458	td = &per_cpu(tick_cpu_device, cpu);
	459	dev = td->evtdev;
	460
	461	if (!(dev->features & CLOCK_EVT_FEAT_C3STOP))
	462	goto out;
	463
	464	if (reason == CLOCK_EVT_NOTIFY_BROADCAST_ENTER) {
	465	if (!cpu_isset(cpu, tick_broadcast_oneshot_mask)) {
	466	cpu_set(cpu, tick_broadcast_oneshot_mask);
	467	clockevents_set_mode(dev, CLOCK_EVT_MODE_SHUTDOWN);
	468	if (dev->next_event.tv64 < bc->next_event.tv64)
	469	tick_broadcast_set_event(dev->next_event, 1);
	470	}
	471	} else {
	472	if (cpu_isset(cpu, tick_broadcast_oneshot_mask)) {
	473	cpu_clear(cpu, tick_broadcast_oneshot_mask);
	474	clockevents_set_mode(dev, CLOCK_EVT_MODE_ONESHOT);
	475	if (dev->next_event.tv64 != KTIME_MAX)
	476	tick_program_event(dev->next_event, 1);
	477	}
	478	}
	479
	480	out:
	481	spin_unlock_irqrestore(&tick_broadcast_lock, flags);
	482	}
	483
5590a536 TG	484	/*
	485	* Reset the one shot broadcast for a cpu
	486	*
	487	* Called with tick_broadcast_lock held
	488	*/
	489	static void tick_broadcast_clear_oneshot(int cpu)
	490	{
	491	cpu_clear(cpu, tick_broadcast_oneshot_mask);
	492	}
	493
7300711e TG	494	static void tick_broadcast_init_next_event(cpumask_t *mask, ktime_t expires)
	495	{
	496	struct tick_device *td;
	497	int cpu;
	498
	499	for_each_cpu_mask_nr(cpu, *mask) {
	500	td = &per_cpu(tick_cpu_device, cpu);
	501	if (td->evtdev)
	502	td->evtdev->next_event = expires;
	503	}
	504	}
	505
79bf2bb3	506	/**
8dce39c2	507	* tick_broadcast_setup_oneshot - setup the broadcast device
79bf2bb3 TG	508	*/
	509	void tick_broadcast_setup_oneshot(struct clock_event_device *bc)
	510	{
9c17bcda TG	511	/* Set it up only once ! */
9c17bcda TG	512	if (bc->event_handler != tick_handle_oneshot_broadcast) {
7300711e TG	513	int was_periodic = bc->mode == CLOCK_EVT_MODE_PERIODIC;
	514	int cpu = smp_processor_id();
	515	cpumask_t mask;
	516
9c17bcda TG	517	bc->event_handler = tick_handle_oneshot_broadcast;
9c17bcda TG	518	clockevents_set_mode(bc, CLOCK_EVT_MODE_ONESHOT);
7300711e TG	519
	520	/* Take the do_timer update */
	521	tick_do_timer_cpu = cpu;
	522
	523	/*
	524	* We must be careful here. There might be other CPUs
	525	* waiting for periodic broadcast. We need to set the
	526	* oneshot_mask bits for those and program the
	527	* broadcast device to fire.
	528	*/
	529	mask = tick_broadcast_mask;
	530	cpu_clear(cpu, mask);
	531	cpus_or(tick_broadcast_oneshot_mask,
	532	tick_broadcast_oneshot_mask, mask);
	533
	534	if (was_periodic && !cpus_empty(mask)) {
	535	tick_broadcast_init_next_event(&mask, tick_next_period);
	536	tick_broadcast_set_event(tick_next_period, 1);
	537	} else
	538	bc->next_event.tv64 = KTIME_MAX;
9c17bcda	539	}
79bf2bb3 TG	540	}
	541
	542	/*
	543	* Select oneshot operating mode for the broadcast device
	544	*/
	545	void tick_broadcast_switch_to_oneshot(void)
	546	{
	547	struct clock_event_device *bc;
	548	unsigned long flags;
	549
	550	spin_lock_irqsave(&tick_broadcast_lock, flags);
	551
	552	tick_broadcast_device.mode = TICKDEV_MODE_ONESHOT;
	553	bc = tick_broadcast_device.evtdev;
	554	if (bc)
	555	tick_broadcast_setup_oneshot(bc);
	556	spin_unlock_irqrestore(&tick_broadcast_lock, flags);
	557	}
	558
	559
	560	/*
	561	* Remove a dead CPU from broadcasting
	562	*/
	563	void tick_shutdown_broadcast_oneshot(unsigned int *cpup)
	564	{
79bf2bb3 TG	565	unsigned long flags;
	566	unsigned int cpu = *cpup;
	567
	568	spin_lock_irqsave(&tick_broadcast_lock, flags);
	569
31d9b393 TG	570	/*
	571	* Clear the broadcast mask flag for the dead cpu, but do not
	572	* stop the broadcast device!
	573	*/
79bf2bb3 TG	574	cpu_clear(cpu, tick_broadcast_oneshot_mask);
79bf2bb3 TG	575
79bf2bb3 TG	576	spin_unlock_irqrestore(&tick_broadcast_lock, flags);
	577	}
	578
	579	#endif