[linux-block.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;
/* FIXME: Use cpumask_var_t. */
static DECLARE_BITMAP(tick_broadcast_mask, NR_CPUS);
static DECLARE_BITMAP(tmpmask, NR_CPUS);
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;
}

struct cpumask *tick_get_broadcast_mask(void)
{
	return to_cpumask(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 (!cpumask_empty(tick_get_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;
		cpumask_set_cpu(cpu, tick_get_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();

			cpumask_clear_cpu(cpu, tick_get_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 (mangled).
 */
static void tick_do_broadcast(struct cpumask *mask)
{
	int cpu = smp_processor_id();
	struct tick_device *td;

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

	if (!cpumask_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)
		 */
		td = &per_cpu(tick_cpu_device, cpumask_first(mask));
		td->evtdev->broadcast(mask);
	}
}

/*
 * Periodic broadcast:
 * - invoke the broadcast handlers
 */
static void tick_do_periodic_broadcast(void)
{
	spin_lock(&tick_broadcast_lock);

	cpumask_and(to_cpumask(tmpmask),
		    cpu_online_mask, tick_get_broadcast_mask());
	tick_do_broadcast(to_cpumask(tmpmask));

	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 = cpumask_empty(tick_get_broadcast_mask());

	switch (*reason) {
	case CLOCK_EVT_NOTIFY_BROADCAST_ON:
	case CLOCK_EVT_NOTIFY_BROADCAST_FORCE:
		if (!cpumask_test_cpu(cpu, tick_get_broadcast_mask())) {
			cpumask_set_cpu(cpu, tick_get_broadcast_mask());
			if (tick_broadcast_device.mode ==
			    TICKDEV_MODE_PERIODIC)
				clockevents_shutdown(dev);
		}
		if (*reason == CLOCK_EVT_NOTIFY_BROADCAST_FORCE)
			tick_broadcast_force = 1;
		break;
	case CLOCK_EVT_NOTIFY_BROADCAST_OFF:
		if (!tick_broadcast_force &&
		    cpumask_test_cpu(cpu, tick_get_broadcast_mask())) {
			cpumask_clear_cpu(cpu, tick_get_broadcast_mask());
			if (tick_broadcast_device.mode ==
			    TICKDEV_MODE_PERIODIC)
				tick_setup_periodic(dev, 0);
		}
		break;
	}

	if (cpumask_empty(tick_get_broadcast_mask())) {
		if (!bc_stopped)
			clockevents_shutdown(bc);
	} 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 (!cpumask_test_cpu(*oncpu, cpu_online_mask))
		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;
	cpumask_clear_cpu(cpu, tick_get_broadcast_mask());

	if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC) {
		if (bc && cpumask_empty(tick_get_broadcast_mask()))
			clockevents_shutdown(bc);
	}

	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_shutdown(bc);

	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 (!cpumask_empty(tick_get_broadcast_mask()))
				tick_broadcast_start_periodic(bc);
			broadcast = cpumask_test_cpu(smp_processor_id(),
						     tick_get_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

/* FIXME: use cpumask_var_t. */
static DECLARE_BITMAP(tick_broadcast_oneshot_mask, NR_CPUS);

/*
 * Exposed for debugging: see timer_list.c
 */
struct cpumask *tick_get_broadcast_oneshot_mask(void)
{
	return to_cpumask(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;
}

/*
 * Called from irq_enter() when idle was interrupted to reenable the
 * per cpu device.
 */
void tick_check_oneshot_broadcast(int cpu)
{
	if (cpumask_test_cpu(cpu, to_cpumask(tick_broadcast_oneshot_mask))) {
		struct tick_device *td = &per_cpu(tick_cpu_device, cpu);

		clockevents_set_mode(td->evtdev, CLOCK_EVT_MODE_ONESHOT);
	}
}

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

	spin_lock(&tick_broadcast_lock);
again:
	dev->next_event.tv64 = KTIME_MAX;
	next_event.tv64 = KTIME_MAX;
	cpumask_clear(to_cpumask(tmpmask));
	now = ktime_get();
	/* Find all expired events */
	for_each_cpu(cpu, tick_get_broadcast_oneshot_mask()) {
		td = &per_cpu(tick_cpu_device, cpu);
		if (td->evtdev->next_event.tv64 <= now.tv64)
			cpumask_set_cpu(cpu, to_cpumask(tmpmask));
		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(to_cpumask(tmpmask));

	/*
	 * 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 (!cpumask_test_cpu(cpu, tick_get_broadcast_oneshot_mask())) {
			cpumask_set_cpu(cpu, tick_get_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 (cpumask_test_cpu(cpu, tick_get_broadcast_oneshot_mask())) {
			cpumask_clear_cpu(cpu,
					  tick_get_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)
{
	cpumask_clear_cpu(cpu, tick_get_broadcast_oneshot_mask());
}

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

	for_each_cpu(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();

		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.
		 */
		cpumask_copy(to_cpumask(tmpmask), tick_get_broadcast_mask());
		cpumask_clear_cpu(cpu, to_cpumask(tmpmask));
		cpumask_or(tick_get_broadcast_oneshot_mask(),
			   tick_get_broadcast_oneshot_mask(),
			   to_cpumask(tmpmask));

		if (was_periodic && !cpumask_empty(to_cpumask(tmpmask))) {
			tick_broadcast_init_next_event(to_cpumask(tmpmask),
						       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!
	 */
	cpumask_clear_cpu(cpu, tick_get_broadcast_oneshot_mask());

	spin_unlock_irqrestore(&tick_broadcast_lock, flags);
}

/*
 * Check, whether the broadcast device is in one shot mode
 */
int tick_broadcast_oneshot_active(void)
{
	return tick_broadcast_device.mode == TICKDEV_MODE_ONESHOT;
}

#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;
6b954823 RR	31	/* FIXME: Use cpumask_var_t. */
	32	static DECLARE_BITMAP(tick_broadcast_mask, NR_CPUS);
	33	static DECLARE_BITMAP(tmpmask, NR_CPUS);
79bf2bb3	34	static DEFINE_SPINLOCK(tick_broadcast_lock);
aa276e1c	35	static int tick_broadcast_force;
f8381cba	36
5590a536 TG	37	#ifdef CONFIG_TICK_ONESHOT
	38	static void tick_broadcast_clear_oneshot(int cpu);
	39	#else
	40	static inline void tick_broadcast_clear_oneshot(int cpu) { }
	41	#endif
	42
289f480a IM	43	/*
	44	* Debugging: see timer_list.c
	45	*/
	46	struct tick_device *tick_get_broadcast_device(void)
	47	{
	48	return &tick_broadcast_device;
	49	}
	50
6b954823	51	struct cpumask *tick_get_broadcast_mask(void)
289f480a	52	{
6b954823	53	return to_cpumask(tick_broadcast_mask);
289f480a IM	54	}
289f480a IM	55
f8381cba TG	56	/*
	57	* Start the device in periodic mode
	58	*/
	59	static void tick_broadcast_start_periodic(struct clock_event_device *bc)
	60	{
18de5bc4	61	if (bc)
f8381cba TG	62	tick_setup_periodic(bc, 1);
	63	}
	64
	65	/*
	66	* Check, if the device can be utilized as broadcast device:
	67	*/
	68	int tick_check_broadcast_device(struct clock_event_device *dev)
	69	{
4a93232d VP	70	if ((tick_broadcast_device.evtdev &&
	71	tick_broadcast_device.evtdev->rating >= dev->rating) \|\|
	72	(dev->features & CLOCK_EVT_FEAT_C3STOP))
f8381cba TG	73	return 0;
	74
	75	clockevents_exchange_device(NULL, dev);
	76	tick_broadcast_device.evtdev = dev;
6b954823	77	if (!cpumask_empty(tick_get_broadcast_mask()))
f8381cba TG	78	tick_broadcast_start_periodic(dev);
	79	return 1;
	80	}
	81
	82	/*
	83	* Check, if the device is the broadcast device
	84	*/
	85	int tick_is_broadcast_device(struct clock_event_device *dev)
	86	{
	87	return (dev && tick_broadcast_device.evtdev == dev);
	88	}
	89
	90	/*
	91	* Check, if the device is disfunctional and a place holder, which
	92	* needs to be handled by the broadcast device.
	93	*/
	94	int tick_device_uses_broadcast(struct clock_event_device *dev, int cpu)
	95	{
	96	unsigned long flags;
	97	int ret = 0;
	98
	99	spin_lock_irqsave(&tick_broadcast_lock, flags);
	100
	101	/*
	102	* Devices might be registered with both periodic and oneshot
	103	* mode disabled. This signals, that the device needs to be
	104	* operated from the broadcast device and is a placeholder for
	105	* the cpu local device.
	106	*/
	107	if (!tick_device_is_functional(dev)) {
	108	dev->event_handler = tick_handle_periodic;
6b954823	109	cpumask_set_cpu(cpu, tick_get_broadcast_mask());
f8381cba TG	110	tick_broadcast_start_periodic(tick_broadcast_device.evtdev);
f8381cba TG	111	ret = 1;
5590a536 TG	112	} else {
	113	/*
	114	* When the new device is not affected by the stop
	115	* feature and the cpu is marked in the broadcast mask
	116	* then clear the broadcast bit.
	117	*/
	118	if (!(dev->features & CLOCK_EVT_FEAT_C3STOP)) {
	119	int cpu = smp_processor_id();
f8381cba	120
6b954823	121	cpumask_clear_cpu(cpu, tick_get_broadcast_mask());
5590a536 TG	122	tick_broadcast_clear_oneshot(cpu);
	123	}
	124	}
f8381cba TG	125	spin_unlock_irqrestore(&tick_broadcast_lock, flags);
	126	return ret;
	127	}
	128
	129	/*
6b954823	130	* Broadcast the event to the cpus, which are set in the mask (mangled).
f8381cba	131	*/
6b954823	132	static void tick_do_broadcast(struct cpumask *mask)
f8381cba	133	{
186e3cb8	134	int cpu = smp_processor_id();
f8381cba TG	135	struct tick_device *td;
	136
	137	/*
	138	* Check, if the current cpu is in the mask
	139	*/
6b954823 RR	140	if (cpumask_test_cpu(cpu, mask)) {
6b954823 RR	141	cpumask_clear_cpu(cpu, mask);
f8381cba TG	142	td = &per_cpu(tick_cpu_device, cpu);
f8381cba TG	143	td->evtdev->event_handler(td->evtdev);
f8381cba TG	144	}
f8381cba TG	145
6b954823	146	if (!cpumask_empty(mask)) {
f8381cba TG	147	/*
	148	* It might be necessary to actually check whether the devices
	149	* have different broadcast functions. For now, just use the
	150	* one of the first device. This works as long as we have this
	151	* misfeature only on x86 (lapic)
	152	*/
6b954823 RR	153	td = &per_cpu(tick_cpu_device, cpumask_first(mask));
6b954823 RR	154	td->evtdev->broadcast(mask);
f8381cba	155	}
f8381cba TG	156	}
	157
	158	/*
	159	* Periodic broadcast:
	160	* - invoke the broadcast handlers
	161	*/
	162	static void tick_do_periodic_broadcast(void)
	163	{
f8381cba TG	164	spin_lock(&tick_broadcast_lock);
f8381cba TG	165
6b954823 RR	166	cpumask_and(to_cpumask(tmpmask),
	167	cpu_online_mask, tick_get_broadcast_mask());
	168	tick_do_broadcast(to_cpumask(tmpmask));
f8381cba TG	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
6b954823	231	bc_stopped = cpumask_empty(tick_get_broadcast_mask());
9c17bcda	232
1595f452 TG	233	switch (*reason) {
	234	case CLOCK_EVT_NOTIFY_BROADCAST_ON:
	235	case CLOCK_EVT_NOTIFY_BROADCAST_FORCE:
6b954823 RR	236	if (!cpumask_test_cpu(cpu, tick_get_broadcast_mask())) {
6b954823 RR	237	cpumask_set_cpu(cpu, tick_get_broadcast_mask());
07454bff TG	238	if (tick_broadcast_device.mode ==
07454bff TG	239	TICKDEV_MODE_PERIODIC)
2344abbc	240	clockevents_shutdown(dev);
f8381cba	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	246	if (!tick_broadcast_force &&
6b954823 RR	247	cpumask_test_cpu(cpu, tick_get_broadcast_mask())) {
6b954823 RR	248	cpumask_clear_cpu(cpu, tick_get_broadcast_mask());
07454bff TG	249	if (tick_broadcast_device.mode ==
07454bff TG	250	TICKDEV_MODE_PERIODIC)
f8381cba TG	251	tick_setup_periodic(dev, 0);
f8381cba TG	252	}
1595f452	253	break;
f8381cba TG	254	}
f8381cba TG	255
6b954823	256	if (cpumask_empty(tick_get_broadcast_mask())) {
9c17bcda	257	if (!bc_stopped)
2344abbc	258	clockevents_shutdown(bc);
9c17bcda	259	} else if (bc_stopped) {
f8381cba TG	260	if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC)
f8381cba TG	261	tick_broadcast_start_periodic(bc);
79bf2bb3 TG	262	else
79bf2bb3 TG	263	tick_broadcast_setup_oneshot(bc);
f8381cba TG	264	}
	265	out:
	266	spin_unlock_irqrestore(&tick_broadcast_lock, flags);
	267	}
	268
	269	/*
	270	* Powerstate information: The system enters/leaves a state, where
	271	* affected devices might stop.
	272	*/
	273	void tick_broadcast_on_off(unsigned long reason, int *oncpu)
	274	{
6b954823	275	if (!cpumask_test_cpu(*oncpu, cpu_online_mask))
833df317	276	printk(KERN_ERR "tick-broadcast: ignoring broadcast for "
72fcde96	277	"offline CPU #%d\n", *oncpu);
bf020cb7 AK	278	else
bf020cb7 AK	279	smp_call_function_single(*oncpu, tick_do_broadcast_on_off,
8691e5a8	280	&reason, 1);
f8381cba TG	281	}
	282
	283	/*
	284	* Set the periodic handler depending on broadcast on/off
	285	*/
	286	void tick_set_periodic_handler(struct clock_event_device *dev, int broadcast)
	287	{
	288	if (!broadcast)
	289	dev->event_handler = tick_handle_periodic;
	290	else
	291	dev->event_handler = tick_handle_periodic_broadcast;
	292	}
	293
	294	/*
	295	* Remove a CPU from broadcasting
	296	*/
	297	void tick_shutdown_broadcast(unsigned int *cpup)
	298	{
	299	struct clock_event_device *bc;
	300	unsigned long flags;
	301	unsigned int cpu = *cpup;
	302
	303	spin_lock_irqsave(&tick_broadcast_lock, flags);
	304
	305	bc = tick_broadcast_device.evtdev;
6b954823	306	cpumask_clear_cpu(cpu, tick_get_broadcast_mask());
f8381cba TG	307
f8381cba TG	308	if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC) {
6b954823	309	if (bc && cpumask_empty(tick_get_broadcast_mask()))
2344abbc	310	clockevents_shutdown(bc);
f8381cba TG	311	}
	312
	313	spin_unlock_irqrestore(&tick_broadcast_lock, flags);
	314	}
79bf2bb3	315
6321dd60 TG	316	void tick_suspend_broadcast(void)
	317	{
	318	struct clock_event_device *bc;
	319	unsigned long flags;
	320
	321	spin_lock_irqsave(&tick_broadcast_lock, flags);
	322
	323	bc = tick_broadcast_device.evtdev;
18de5bc4	324	if (bc)
2344abbc	325	clockevents_shutdown(bc);
6321dd60 TG	326
	327	spin_unlock_irqrestore(&tick_broadcast_lock, flags);
	328	}
	329
	330	int tick_resume_broadcast(void)
	331	{
	332	struct clock_event_device *bc;
	333	unsigned long flags;
	334	int broadcast = 0;
	335
	336	spin_lock_irqsave(&tick_broadcast_lock, flags);
	337
	338	bc = tick_broadcast_device.evtdev;
6321dd60	339
cd05a1f8	340	if (bc) {
18de5bc4 TG	341	clockevents_set_mode(bc, CLOCK_EVT_MODE_RESUME);
18de5bc4 TG	342
cd05a1f8 TG	343	switch (tick_broadcast_device.mode) {
cd05a1f8 TG	344	case TICKDEV_MODE_PERIODIC:
6b954823	345	if (!cpumask_empty(tick_get_broadcast_mask()))
cd05a1f8	346	tick_broadcast_start_periodic(bc);
6b954823 RR	347	broadcast = cpumask_test_cpu(smp_processor_id(),
6b954823 RR	348	tick_get_broadcast_mask());
cd05a1f8 TG	349	break;
	350	case TICKDEV_MODE_ONESHOT:
	351	broadcast = tick_resume_broadcast_oneshot(bc);
	352	break;
	353	}
6321dd60 TG	354	}
	355	spin_unlock_irqrestore(&tick_broadcast_lock, flags);
	356
	357	return broadcast;
	358	}
	359
	360
79bf2bb3 TG	361	#ifdef CONFIG_TICK_ONESHOT
79bf2bb3 TG	362
6b954823 RR	363	/* FIXME: use cpumask_var_t. */
6b954823 RR	364	static DECLARE_BITMAP(tick_broadcast_oneshot_mask, NR_CPUS);
79bf2bb3	365
289f480a	366	/*
6b954823	367	* Exposed for debugging: see timer_list.c
289f480a	368	*/
6b954823	369	struct cpumask *tick_get_broadcast_oneshot_mask(void)
289f480a	370	{
6b954823	371	return to_cpumask(tick_broadcast_oneshot_mask);
289f480a IM	372	}
289f480a IM	373
79bf2bb3 TG	374	static int tick_broadcast_set_event(ktime_t expires, int force)
	375	{
	376	struct clock_event_device *bc = tick_broadcast_device.evtdev;
1fb9b7d2 TG	377
1fb9b7d2 TG	378	return tick_dev_program_event(bc, expires, force);
79bf2bb3 TG	379	}
79bf2bb3 TG	380
cd05a1f8 TG	381	int tick_resume_broadcast_oneshot(struct clock_event_device *bc)
	382	{
	383	clockevents_set_mode(bc, CLOCK_EVT_MODE_ONESHOT);
b7e113dc	384	return 0;
cd05a1f8 TG	385	}
cd05a1f8 TG	386
fb02fbc1 TG	387	/*
	388	* Called from irq_enter() when idle was interrupted to reenable the
	389	* per cpu device.
	390	*/
	391	void tick_check_oneshot_broadcast(int cpu)
	392	{
6b954823	393	if (cpumask_test_cpu(cpu, to_cpumask(tick_broadcast_oneshot_mask))) {
fb02fbc1 TG	394	struct tick_device *td = &per_cpu(tick_cpu_device, cpu);
	395
	396	clockevents_set_mode(td->evtdev, CLOCK_EVT_MODE_ONESHOT);
	397	}
	398	}
	399
79bf2bb3 TG	400	/*
	401	* Handle oneshot mode broadcasting
	402	*/
	403	static void tick_handle_oneshot_broadcast(struct clock_event_device *dev)
	404	{
	405	struct tick_device *td;
cdc6f27d	406	ktime_t now, next_event;
79bf2bb3 TG	407	int cpu;
	408
	409	spin_lock(&tick_broadcast_lock);
	410	again:
	411	dev->next_event.tv64 = KTIME_MAX;
cdc6f27d	412	next_event.tv64 = KTIME_MAX;
6b954823	413	cpumask_clear(to_cpumask(tmpmask));
79bf2bb3 TG	414	now = ktime_get();
79bf2bb3 TG	415	/* Find all expired events */
6b954823	416	for_each_cpu(cpu, tick_get_broadcast_oneshot_mask()) {
79bf2bb3 TG	417	td = &per_cpu(tick_cpu_device, cpu);
79bf2bb3 TG	418	if (td->evtdev->next_event.tv64 <= now.tv64)
6b954823	419	cpumask_set_cpu(cpu, to_cpumask(tmpmask));
cdc6f27d TG	420	else if (td->evtdev->next_event.tv64 < next_event.tv64)
cdc6f27d TG	421	next_event.tv64 = td->evtdev->next_event.tv64;
79bf2bb3 TG	422	}
	423
	424	/*
cdc6f27d TG	425	* Wakeup the cpus which have an expired event.
cdc6f27d TG	426	*/
6b954823	427	tick_do_broadcast(to_cpumask(tmpmask));
cdc6f27d TG	428
	429	/*
	430	* Two reasons for reprogram:
	431	*
	432	* - The global event did not expire any CPU local
	433	* events. This happens in dyntick mode, as the maximum PIT
	434	* delta is quite small.
	435	*
	436	* - There are pending events on sleeping CPUs which were not
	437	* in the event mask
79bf2bb3	438	*/
cdc6f27d	439	if (next_event.tv64 != KTIME_MAX) {
79bf2bb3	440	/*
cdc6f27d TG	441	* Rearm the broadcast device. If event expired,
cdc6f27d TG	442	* repeat the above
79bf2bb3	443	*/
cdc6f27d	444	if (tick_broadcast_set_event(next_event, 0))
79bf2bb3 TG	445	goto again;
	446	}
	447	spin_unlock(&tick_broadcast_lock);
	448	}
	449
	450	/*
	451	* Powerstate information: The system enters/leaves a state, where
	452	* affected devices might stop
	453	*/
	454	void tick_broadcast_oneshot_control(unsigned long reason)
	455	{
	456	struct clock_event_device bc, dev;
	457	struct tick_device *td;
	458	unsigned long flags;
	459	int cpu;
	460
	461	spin_lock_irqsave(&tick_broadcast_lock, flags);
	462
	463	/*
	464	* Periodic mode does not care about the enter/exit of power
	465	* states
	466	*/
	467	if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC)
	468	goto out;
	469
	470	bc = tick_broadcast_device.evtdev;
	471	cpu = smp_processor_id();
	472	td = &per_cpu(tick_cpu_device, cpu);
	473	dev = td->evtdev;
	474
	475	if (!(dev->features & CLOCK_EVT_FEAT_C3STOP))
	476	goto out;
	477
	478	if (reason == CLOCK_EVT_NOTIFY_BROADCAST_ENTER) {
6b954823 RR	479	if (!cpumask_test_cpu(cpu, tick_get_broadcast_oneshot_mask())) {
6b954823 RR	480	cpumask_set_cpu(cpu, tick_get_broadcast_oneshot_mask());
79bf2bb3 TG	481	clockevents_set_mode(dev, CLOCK_EVT_MODE_SHUTDOWN);
	482	if (dev->next_event.tv64 < bc->next_event.tv64)
	483	tick_broadcast_set_event(dev->next_event, 1);
	484	}
	485	} else {
6b954823 RR	486	if (cpumask_test_cpu(cpu, tick_get_broadcast_oneshot_mask())) {
	487	cpumask_clear_cpu(cpu,
	488	tick_get_broadcast_oneshot_mask());
79bf2bb3 TG	489	clockevents_set_mode(dev, CLOCK_EVT_MODE_ONESHOT);
	490	if (dev->next_event.tv64 != KTIME_MAX)
	491	tick_program_event(dev->next_event, 1);
	492	}
	493	}
	494
	495	out:
	496	spin_unlock_irqrestore(&tick_broadcast_lock, flags);
	497	}
	498
5590a536 TG	499	/*
	500	* Reset the one shot broadcast for a cpu
	501	*
	502	* Called with tick_broadcast_lock held
	503	*/
	504	static void tick_broadcast_clear_oneshot(int cpu)
	505	{
6b954823	506	cpumask_clear_cpu(cpu, tick_get_broadcast_oneshot_mask());
5590a536 TG	507	}
5590a536 TG	508
6b954823 RR	509	static void tick_broadcast_init_next_event(struct cpumask *mask,
6b954823 RR	510	ktime_t expires)
7300711e TG	511	{
	512	struct tick_device *td;
	513	int cpu;
	514
5db0e1e9	515	for_each_cpu(cpu, mask) {
7300711e TG	516	td = &per_cpu(tick_cpu_device, cpu);
	517	if (td->evtdev)
	518	td->evtdev->next_event = expires;
	519	}
	520	}
	521
79bf2bb3	522	/**
8dce39c2	523	* tick_broadcast_setup_oneshot - setup the broadcast device
79bf2bb3 TG	524	*/
	525	void tick_broadcast_setup_oneshot(struct clock_event_device *bc)
	526	{
9c17bcda TG	527	/* Set it up only once ! */
9c17bcda TG	528	if (bc->event_handler != tick_handle_oneshot_broadcast) {
7300711e TG	529	int was_periodic = bc->mode == CLOCK_EVT_MODE_PERIODIC;
7300711e TG	530	int cpu = smp_processor_id();
7300711e	531
9c17bcda TG	532	bc->event_handler = tick_handle_oneshot_broadcast;
9c17bcda TG	533	clockevents_set_mode(bc, CLOCK_EVT_MODE_ONESHOT);
7300711e TG	534
	535	/* Take the do_timer update */
	536	tick_do_timer_cpu = cpu;
	537
	538	/*
	539	* We must be careful here. There might be other CPUs
	540	* waiting for periodic broadcast. We need to set the
	541	* oneshot_mask bits for those and program the
	542	* broadcast device to fire.
	543	*/
6b954823 RR	544	cpumask_copy(to_cpumask(tmpmask), tick_get_broadcast_mask());
	545	cpumask_clear_cpu(cpu, to_cpumask(tmpmask));
	546	cpumask_or(tick_get_broadcast_oneshot_mask(),
	547	tick_get_broadcast_oneshot_mask(),
	548	to_cpumask(tmpmask));
	549
	550	if (was_periodic && !cpumask_empty(to_cpumask(tmpmask))) {
	551	tick_broadcast_init_next_event(to_cpumask(tmpmask),
	552	tick_next_period);
7300711e TG	553	tick_broadcast_set_event(tick_next_period, 1);
	554	} else
	555	bc->next_event.tv64 = KTIME_MAX;
9c17bcda	556	}
79bf2bb3 TG	557	}
	558
	559	/*
	560	* Select oneshot operating mode for the broadcast device
	561	*/
	562	void tick_broadcast_switch_to_oneshot(void)
	563	{
	564	struct clock_event_device *bc;
	565	unsigned long flags;
	566
	567	spin_lock_irqsave(&tick_broadcast_lock, flags);
	568
	569	tick_broadcast_device.mode = TICKDEV_MODE_ONESHOT;
	570	bc = tick_broadcast_device.evtdev;
	571	if (bc)
	572	tick_broadcast_setup_oneshot(bc);
	573	spin_unlock_irqrestore(&tick_broadcast_lock, flags);
	574	}
	575
	576
	577	/*
	578	* Remove a dead CPU from broadcasting
	579	*/
	580	void tick_shutdown_broadcast_oneshot(unsigned int *cpup)
	581	{
79bf2bb3 TG	582	unsigned long flags;
	583	unsigned int cpu = *cpup;
	584
	585	spin_lock_irqsave(&tick_broadcast_lock, flags);
	586
31d9b393 TG	587	/*
	588	* Clear the broadcast mask flag for the dead cpu, but do not
	589	* stop the broadcast device!
	590	*/
6b954823	591	cpumask_clear_cpu(cpu, tick_get_broadcast_oneshot_mask());
79bf2bb3	592
79bf2bb3 TG	593	spin_unlock_irqrestore(&tick_broadcast_lock, flags);
	594	}
	595
27ce4cb4 TG	596	/*
	597	* Check, whether the broadcast device is in one shot mode
	598	*/
	599	int tick_broadcast_oneshot_active(void)
	600	{
	601	return tick_broadcast_device.mode == TICKDEV_MODE_ONESHOT;
	602	}
	603
79bf2bb3	604	#endif