[deliverable/linux.git] / kernel / time / tick-broadcast.c

/*
 * linux/kernel/time/tick-broadcast.c
 *
 * This file contains functions which emulate a local clock-event
 * device via a broadcast event source.
 *
 * Copyright(C) 2005-2006, Thomas Gleixner <tglx@linutronix.de>
 * Copyright(C) 2005-2007, Red Hat, Inc., Ingo Molnar
 * Copyright(C) 2006-2007, Timesys Corp., Thomas Gleixner
 *
 * This code is licenced under the GPL version 2. For details see
 * kernel-base/COPYING.
 */
#include <linux/cpu.h>
#include <linux/err.h>
#include <linux/hrtimer.h>
#include <linux/irq.h>
#include <linux/percpu.h>
#include <linux/profile.h>
#include <linux/sched.h>
#include <linux/tick.h>

#include "tick-internal.h"

/*
 * Broadcast support for broken x86 hardware, where the local apic
 * timer stops in C3 state.
 */

struct tick_device tick_broadcast_device;
static cpumask_t tick_broadcast_mask;
static DEFINE_SPINLOCK(tick_broadcast_lock);

#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 ||
	    (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
 */
int tick_do_broadcast(cpumask_t mask)
{
	int ret = 0, cpu = smp_processor_id();
	struct tick_device *td;

	/*
	 * Check, if the current cpu is in the mask
	 */
	if (cpu_isset(cpu, mask)) {
		cpu_clear(cpu, mask);
		td = &per_cpu(tick_cpu_device, cpu);
		td->evtdev->event_handler(td->evtdev);
		ret = 1;
	}

	if (!cpus_empty(mask)) {
		/*
		 * It might be necessary to actually check whether the devices
		 * have different broadcast functions. For now, just use the
		 * one of the first device. This works as long as we have this
		 * misfeature only on x86 (lapic)
		 */
		cpu = first_cpu(mask);
		td = &per_cpu(tick_cpu_device, cpu);
		td->evtdev->broadcast(mask);
		ret = 1;
	}
	return ret;
}

/*
 * Periodic broadcast:
 * - invoke the broadcast handlers
 */
static void tick_do_periodic_broadcast(void)
{
	cpumask_t mask;

	spin_lock(&tick_broadcast_lock);

	cpus_and(mask, cpu_online_map, tick_broadcast_mask);
	tick_do_broadcast(mask);

	spin_unlock(&tick_broadcast_lock);
}

/*
 * Event handler for periodic broadcast ticks
 */
static void tick_handle_periodic_broadcast(struct clock_event_device *dev)
{
	dev->next_event.tv64 = KTIME_MAX;

	tick_do_periodic_broadcast();

	/*
	 * The device is in periodic mode. No reprogramming necessary:
	 */
	if (dev->mode == CLOCK_EVT_MODE_PERIODIC)
		return;

	/*
	 * Setup the next period for devices, which do not have
	 * periodic mode:
	 */
	for (;;) {
		ktime_t next = ktime_add(dev->next_event, tick_period);

		if (!clockevents_program_event(dev, next, ktime_get()))
			return;
		tick_do_periodic_broadcast();
	}
}

/*
 * Powerstate information: The system enters/leaves a state, where
 * affected devices might stop
 */
static void tick_do_broadcast_on_off(void *why)
{
	struct clock_event_device *bc, *dev;
	struct tick_device *td;
	unsigned long flags, *reason = why;
	int cpu;

	spin_lock_irqsave(&tick_broadcast_lock, flags);

	cpu = smp_processor_id();
	td = &per_cpu(tick_cpu_device, cpu);
	dev = td->evtdev;
	bc = tick_broadcast_device.evtdev;

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

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

	if (cpus_empty(tick_broadcast_mask))
		clockevents_set_mode(bc, CLOCK_EVT_MODE_SHUTDOWN);
	else {
		if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC)
			tick_broadcast_start_periodic(bc);
		else
			tick_broadcast_setup_oneshot(bc);
	}
out:
	spin_unlock_irqrestore(&tick_broadcast_lock, flags);
}

/*
 * Powerstate information: The system enters/leaves a state, where
 * affected devices might stop.
 */
void tick_broadcast_on_off(unsigned long reason, int *oncpu)
{
	int cpu = get_cpu();

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

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

/*
 * Set the periodic handler depending on broadcast on/off
 */
void tick_set_periodic_handler(struct clock_event_device *dev, int broadcast)
{
	if (!broadcast)
		dev->event_handler = tick_handle_periodic;
	else
		dev->event_handler = tick_handle_periodic_broadcast;
}

/*
 * Remove a CPU from broadcasting
 */
void tick_shutdown_broadcast(unsigned int *cpup)
{
	struct clock_event_device *bc;
	unsigned long flags;
	unsigned int cpu = *cpup;

	spin_lock_irqsave(&tick_broadcast_lock, flags);

	bc = tick_broadcast_device.evtdev;
	cpu_clear(cpu, tick_broadcast_mask);

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

	spin_unlock_irqrestore(&tick_broadcast_lock, flags);
}

void tick_suspend_broadcast(void)
{
	struct clock_event_device *bc;
	unsigned long flags;

	spin_lock_irqsave(&tick_broadcast_lock, flags);

	bc = tick_broadcast_device.evtdev;
	if (bc)
		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)
{
	int cpu = smp_processor_id();

	/*
	 * If the CPU is marked for broadcast, enforce oneshot
	 * broadcast mode. The jinxed VAIO does not resume otherwise.
	 * No idea why it ends up in a lower C State during resume
	 * without notifying the clock events layer.
	 */
	if (cpu_isset(cpu, tick_broadcast_mask))
		cpu_set(cpu, tick_broadcast_oneshot_mask);

	clockevents_set_mode(bc, CLOCK_EVT_MODE_ONESHOT);

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

	return cpu_isset(cpu, tick_broadcast_oneshot_mask);
}

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

	/*
	 * Find the event which expires next:
	 */
	for (cpu = first_cpu(tick_broadcast_oneshot_mask); cpu != NR_CPUS;
	     cpu = next_cpu(cpu, tick_broadcast_oneshot_mask)) {
		td = &per_cpu(tick_cpu_device, cpu);
		if (td->evtdev->next_event.tv64 < expires.tv64)
			expires = td->evtdev->next_event;
	}

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

	return tick_broadcast_set_event(expires, 0);
}

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

	spin_lock(&tick_broadcast_lock);
again:
	dev->next_event.tv64 = KTIME_MAX;
	mask = CPU_MASK_NONE;
	now = ktime_get();
	/* Find all expired events */
	for (cpu = first_cpu(tick_broadcast_oneshot_mask); cpu != NR_CPUS;
	     cpu = next_cpu(cpu, tick_broadcast_oneshot_mask)) {
		td = &per_cpu(tick_cpu_device, cpu);
		if (td->evtdev->next_event.tv64 <= now.tv64)
			cpu_set(cpu, mask);
	}

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

/*
 * Powerstate information: The system enters/leaves a state, where
 * affected devices might stop
 */
void tick_broadcast_oneshot_control(unsigned long reason)
{
	struct clock_event_device *bc, *dev;
	struct tick_device *td;
	unsigned long flags;
	int cpu;

	spin_lock_irqsave(&tick_broadcast_lock, flags);

	/*
	 * Periodic mode does not care about the enter/exit of power
	 * states
	 */
	if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC)
		goto out;

	bc = tick_broadcast_device.evtdev;
	cpu = smp_processor_id();
	td = &per_cpu(tick_cpu_device, cpu);
	dev = td->evtdev;

	if (!(dev->features & CLOCK_EVT_FEAT_C3STOP))
		goto out;

	if (reason == CLOCK_EVT_NOTIFY_BROADCAST_ENTER) {
		if (!cpu_isset(cpu, tick_broadcast_oneshot_mask)) {
			cpu_set(cpu, tick_broadcast_oneshot_mask);
			clockevents_set_mode(dev, CLOCK_EVT_MODE_SHUTDOWN);
			if (dev->next_event.tv64 < bc->next_event.tv64)
				tick_broadcast_set_event(dev->next_event, 1);
		}
	} else {
		if (cpu_isset(cpu, tick_broadcast_oneshot_mask)) {
			cpu_clear(cpu, tick_broadcast_oneshot_mask);
			clockevents_set_mode(dev, CLOCK_EVT_MODE_ONESHOT);
			if (dev->next_event.tv64 != KTIME_MAX)
				tick_program_event(dev->next_event, 1);
		}
	}

out:
	spin_unlock_irqrestore(&tick_broadcast_lock, flags);
}

/*
 * 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_highres - setup the broadcast device for highres
 */
void tick_broadcast_setup_oneshot(struct clock_event_device *bc)
{
	if (bc->mode != CLOCK_EVT_MODE_ONESHOT) {
		bc->event_handler = tick_handle_oneshot_broadcast;
		clockevents_set_mode(bc, CLOCK_EVT_MODE_ONESHOT);
		bc->next_event.tv64 = KTIME_MAX;
	}
}

/*
 * Select oneshot operating mode for the broadcast device
 */
void tick_broadcast_switch_to_oneshot(void)
{
	struct clock_event_device *bc;
	unsigned long flags;

	spin_lock_irqsave(&tick_broadcast_lock, flags);

	tick_broadcast_device.mode = TICKDEV_MODE_ONESHOT;
	bc = tick_broadcast_device.evtdev;
	if (bc)
		tick_broadcast_setup_oneshot(bc);
	spin_unlock_irqrestore(&tick_broadcast_lock, flags);
}


/*
 * Remove a dead CPU from broadcasting
 */
void tick_shutdown_broadcast_oneshot(unsigned int *cpup)
{
	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>
	17	#include <linux/irq.h>
	18	#include <linux/percpu.h>
	19	#include <linux/profile.h>
	20	#include <linux/sched.h>
	21	#include <linux/tick.h>
	22
	23	#include "tick-internal.h"
	24
	25	/*
	26	* Broadcast support for broken x86 hardware, where the local apic
	27	* timer stops in C3 state.
	28	*/
	29
	30	struct tick_device tick_broadcast_device;
	31	static cpumask_t tick_broadcast_mask;
79bf2bb3	32	static DEFINE_SPINLOCK(tick_broadcast_lock);
f8381cba	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	{
	67	if (tick_broadcast_device.evtdev \|\|
	68	(dev->features & CLOCK_EVT_FEAT_C3STOP))
	69	return 0;
	70
	71	clockevents_exchange_device(NULL, dev);
	72	tick_broadcast_device.evtdev = dev;
	73	if (!cpus_empty(tick_broadcast_mask))
	74	tick_broadcast_start_periodic(dev);
	75	return 1;
	76	}
	77
	78	/*
	79	* Check, if the device is the broadcast device
	80	*/
	81	int tick_is_broadcast_device(struct clock_event_device *dev)
	82	{
	83	return (dev && tick_broadcast_device.evtdev == dev);
	84	}
	85
	86	/*
	87	* Check, if the device is disfunctional and a place holder, which
	88	* needs to be handled by the broadcast device.
	89	*/
	90	int tick_device_uses_broadcast(struct clock_event_device *dev, int cpu)
	91	{
	92	unsigned long flags;
	93	int ret = 0;
	94
	95	spin_lock_irqsave(&tick_broadcast_lock, flags);
	96
	97	/*
	98	* Devices might be registered with both periodic and oneshot
	99	* mode disabled. This signals, that the device needs to be
	100	* operated from the broadcast device and is a placeholder for
	101	* the cpu local device.
	102	*/
	103	if (!tick_device_is_functional(dev)) {
	104	dev->event_handler = tick_handle_periodic;
	105	cpu_set(cpu, tick_broadcast_mask);
	106	tick_broadcast_start_periodic(tick_broadcast_device.evtdev);
	107	ret = 1;
5590a536 TG	108	} else {
	109	/*
	110	* When the new device is not affected by the stop
	111	* feature and the cpu is marked in the broadcast mask
	112	* then clear the broadcast bit.
	113	*/
	114	if (!(dev->features & CLOCK_EVT_FEAT_C3STOP)) {
	115	int cpu = smp_processor_id();
f8381cba	116
5590a536 TG	117	cpu_clear(cpu, tick_broadcast_mask);
	118	tick_broadcast_clear_oneshot(cpu);
	119	}
	120	}
f8381cba TG	121	spin_unlock_irqrestore(&tick_broadcast_lock, flags);
	122	return ret;
	123	}
	124
	125	/*
	126	* Broadcast the event to the cpus, which are set in the mask
	127	*/
	128	int tick_do_broadcast(cpumask_t mask)
	129	{
	130	int ret = 0, cpu = smp_processor_id();
	131	struct tick_device *td;
	132
	133	/*
	134	* Check, if the current cpu is in the mask
	135	*/
	136	if (cpu_isset(cpu, mask)) {
	137	cpu_clear(cpu, mask);
	138	td = &per_cpu(tick_cpu_device, cpu);
	139	td->evtdev->event_handler(td->evtdev);
	140	ret = 1;
	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);
	153	ret = 1;
	154	}
	155	return ret;
	156	}
	157
	158	/*
	159	* Periodic broadcast:
	160	* - invoke the broadcast handlers
	161	*/
	162	static void tick_do_periodic_broadcast(void)
	163	{
	164	cpumask_t mask;
	165
	166	spin_lock(&tick_broadcast_lock);
	167
	168	cpus_and(mask, cpu_online_map, tick_broadcast_mask);
	169	tick_do_broadcast(mask);
	170
	171	spin_unlock(&tick_broadcast_lock);
	172	}
	173
	174	/*
	175	* Event handler for periodic broadcast ticks
	176	*/
	177	static void tick_handle_periodic_broadcast(struct clock_event_device *dev)
	178	{
	179	dev->next_event.tv64 = KTIME_MAX;
	180
	181	tick_do_periodic_broadcast();
	182
	183	/*
	184	* The device is in periodic mode. No reprogramming necessary:
185	*/
186	if (dev->mode == CLOCK_EVT_MODE_PERIODIC)
187	return;
188
189	/*
190	* Setup the next period for devices, which do not have
191	* periodic mode:
192	*/
193	for (;;) {
194	ktime_t next = ktime_add(dev->next_event, tick_period);
195
196	if (!clockevents_program_event(dev, next, ktime_get()))
197	return;
198	tick_do_periodic_broadcast();
199	}
200	}
201
202	/*
203	* Powerstate information: The system enters/leaves a state, where
204	* affected devices might stop
205	*/
206	static void tick_do_broadcast_on_off(void *why)
207	{
208	struct clock_event_device bc, dev;
209	struct tick_device *td;
210	unsigned long flags, *reason = why;
211	int cpu;
212
213	spin_lock_irqsave(&tick_broadcast_lock, flags);
214
215	cpu = smp_processor_id();
216	td = &per_cpu(tick_cpu_device, cpu);
217	dev = td->evtdev;
218	bc = tick_broadcast_device.evtdev;
219
220	/*
221	* Is the device in broadcast mode forever or is it not
222	* affected by the powerstate ?
223	*/
224	if (!dev \|\| !tick_device_is_functional(dev) \|\|
225	!(dev->features & CLOCK_EVT_FEAT_C3STOP))
226	goto out;
227
228	if (*reason == CLOCK_EVT_NOTIFY_BROADCAST_ON) {
229	if (!cpu_isset(cpu, tick_broadcast_mask)) {
230	cpu_set(cpu, tick_broadcast_mask);
231	if (td->mode == TICKDEV_MODE_PERIODIC)
232	clockevents_set_mode(dev,
233	CLOCK_EVT_MODE_SHUTDOWN);
234	}
235	} else {
236	if (cpu_isset(cpu, tick_broadcast_mask)) {
237	cpu_clear(cpu, tick_broadcast_mask);
238	if (td->mode == TICKDEV_MODE_PERIODIC)
239	tick_setup_periodic(dev, 0);
240	}
241	}
242
243	if (cpus_empty(tick_broadcast_mask))
244	clockevents_set_mode(bc, CLOCK_EVT_MODE_SHUTDOWN);
245	else {
246	if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC)
247	tick_broadcast_start_periodic(bc);
79bf2bb3 TG	248	else
79bf2bb3 TG	249	tick_broadcast_setup_oneshot(bc);
f8381cba TG	250	}
	251	out:
	252	spin_unlock_irqrestore(&tick_broadcast_lock, flags);
	253	}
	254
	255	/*
	256	* Powerstate information: The system enters/leaves a state, where
	257	* affected devices might stop.
	258	*/
	259	void tick_broadcast_on_off(unsigned long reason, int *oncpu)
	260	{
	261	int cpu = get_cpu();
	262
72fcde96 TG	263	if (!cpu_isset(*oncpu, cpu_online_map)) {
	264	printk(KERN_ERR "tick-braodcast: ignoring broadcast for "
	265	"offline CPU #%d\n", *oncpu);
	266	} else {
	267
	268	if (cpu == *oncpu)
	269	tick_do_broadcast_on_off(&reason);
	270	else
	271	smp_call_function_single(*oncpu,
	272	tick_do_broadcast_on_off,
	273	&reason, 1, 1);
	274	}
f8381cba TG	275	put_cpu();
	276	}
	277
	278	/*
	279	* Set the periodic handler depending on broadcast on/off
	280	*/
	281	void tick_set_periodic_handler(struct clock_event_device *dev, int broadcast)
	282	{
	283	if (!broadcast)
	284	dev->event_handler = tick_handle_periodic;
	285	else
	286	dev->event_handler = tick_handle_periodic_broadcast;
	287	}
	288
	289	/*
	290	* Remove a CPU from broadcasting
	291	*/
	292	void tick_shutdown_broadcast(unsigned int *cpup)
	293	{
	294	struct clock_event_device *bc;
	295	unsigned long flags;
	296	unsigned int cpu = *cpup;
	297
	298	spin_lock_irqsave(&tick_broadcast_lock, flags);
	299
	300	bc = tick_broadcast_device.evtdev;
	301	cpu_clear(cpu, tick_broadcast_mask);
	302
	303	if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC) {
	304	if (bc && cpus_empty(tick_broadcast_mask))
	305	clockevents_set_mode(bc, CLOCK_EVT_MODE_SHUTDOWN);
	306	}
	307
	308	spin_unlock_irqrestore(&tick_broadcast_lock, flags);
	309	}
79bf2bb3	310
6321dd60 TG	311	void tick_suspend_broadcast(void)
	312	{
	313	struct clock_event_device *bc;
	314	unsigned long flags;
	315
	316	spin_lock_irqsave(&tick_broadcast_lock, flags);
	317
	318	bc = tick_broadcast_device.evtdev;
18de5bc4	319	if (bc)
6321dd60 TG	320	clockevents_set_mode(bc, CLOCK_EVT_MODE_SHUTDOWN);
	321
	322	spin_unlock_irqrestore(&tick_broadcast_lock, flags);
	323	}
	324
	325	int tick_resume_broadcast(void)
	326	{
	327	struct clock_event_device *bc;
	328	unsigned long flags;
	329	int broadcast = 0;
	330
	331	spin_lock_irqsave(&tick_broadcast_lock, flags);
	332
	333	bc = tick_broadcast_device.evtdev;
6321dd60	334
cd05a1f8	335	if (bc) {
18de5bc4 TG	336	clockevents_set_mode(bc, CLOCK_EVT_MODE_RESUME);
18de5bc4 TG	337
cd05a1f8 TG	338	switch (tick_broadcast_device.mode) {
	339	case TICKDEV_MODE_PERIODIC:
	340	if(!cpus_empty(tick_broadcast_mask))
	341	tick_broadcast_start_periodic(bc);
	342	broadcast = cpu_isset(smp_processor_id(),
	343	tick_broadcast_mask);
	344	break;
	345	case TICKDEV_MODE_ONESHOT:
	346	broadcast = tick_resume_broadcast_oneshot(bc);
	347	break;
	348	}
6321dd60 TG	349	}
	350	spin_unlock_irqrestore(&tick_broadcast_lock, flags);
	351
	352	return broadcast;
	353	}
	354
	355
79bf2bb3 TG	356	#ifdef CONFIG_TICK_ONESHOT
	357
	358	static cpumask_t tick_broadcast_oneshot_mask;
	359
289f480a IM	360	/*
	361	* Debugging: see timer_list.c
	362	*/
	363	cpumask_t *tick_get_broadcast_oneshot_mask(void)
	364	{
	365	return &tick_broadcast_oneshot_mask;
	366	}
	367
79bf2bb3 TG	368	static int tick_broadcast_set_event(ktime_t expires, int force)
	369	{
	370	struct clock_event_device *bc = tick_broadcast_device.evtdev;
	371	ktime_t now = ktime_get();
	372	int res;
	373
	374	for(;;) {
	375	res = clockevents_program_event(bc, expires, now);
	376	if (!res \|\| !force)
	377	return res;
	378	now = ktime_get();
	379	expires = ktime_add(now, ktime_set(0, bc->min_delta_ns));
	380	}
	381	}
	382
cd05a1f8 TG	383	int tick_resume_broadcast_oneshot(struct clock_event_device *bc)
cd05a1f8 TG	384	{
07eec6af TG	385	int cpu = smp_processor_id();
	386
	387	/*
	388	* If the CPU is marked for broadcast, enforce oneshot
	389	* broadcast mode. The jinxed VAIO does not resume otherwise.
	390	* No idea why it ends up in a lower C State during resume
	391	* without notifying the clock events layer.
	392	*/
	393	if (cpu_isset(cpu, tick_broadcast_mask))
	394	cpu_set(cpu, tick_broadcast_oneshot_mask);
	395
cd05a1f8 TG	396	clockevents_set_mode(bc, CLOCK_EVT_MODE_ONESHOT);
	397
	398	if(!cpus_empty(tick_broadcast_oneshot_mask))
	399	tick_broadcast_set_event(ktime_get(), 1);
	400
07eec6af	401	return cpu_isset(cpu, tick_broadcast_oneshot_mask);
cd05a1f8 TG	402	}
cd05a1f8 TG	403
79bf2bb3 TG	404	/*
	405	* Reprogram the broadcast device:
	406	*
	407	* Called with tick_broadcast_lock held and interrupts disabled.
	408	*/
	409	static int tick_broadcast_reprogram(void)
	410	{
	411	ktime_t expires = { .tv64 = KTIME_MAX };
	412	struct tick_device *td;
	413	int cpu;
	414
	415	/*
	416	* Find the event which expires next:
	417	*/
	418	for (cpu = first_cpu(tick_broadcast_oneshot_mask); cpu != NR_CPUS;
	419	cpu = next_cpu(cpu, tick_broadcast_oneshot_mask)) {
	420	td = &per_cpu(tick_cpu_device, cpu);
	421	if (td->evtdev->next_event.tv64 < expires.tv64)
	422	expires = td->evtdev->next_event;
	423	}
	424
	425	if (expires.tv64 == KTIME_MAX)
	426	return 0;
	427
	428	return tick_broadcast_set_event(expires, 0);
	429	}
	430
	431	/*
	432	* Handle oneshot mode broadcasting
	433	*/
	434	static void tick_handle_oneshot_broadcast(struct clock_event_device *dev)
	435	{
	436	struct tick_device *td;
	437	cpumask_t mask;
	438	ktime_t now;
	439	int cpu;
	440
	441	spin_lock(&tick_broadcast_lock);
	442	again:
	443	dev->next_event.tv64 = KTIME_MAX;
	444	mask = CPU_MASK_NONE;
	445	now = ktime_get();
	446	/* Find all expired events */
	447	for (cpu = first_cpu(tick_broadcast_oneshot_mask); cpu != NR_CPUS;
	448	cpu = next_cpu(cpu, tick_broadcast_oneshot_mask)) {
	449	td = &per_cpu(tick_cpu_device, cpu);
	450	if (td->evtdev->next_event.tv64 <= now.tv64)
	451	cpu_set(cpu, mask);
	452	}
	453
	454	/*
	455	* Wakeup the cpus which have an expired event. The broadcast
	456	* device is reprogrammed in the return from idle code.
	457	*/
	458	if (!tick_do_broadcast(mask)) {
	459	/*
	460	* The global event did not expire any CPU local
	461	* events. This happens in dyntick mode, as the
	462	* maximum PIT delta is quite small.
	463	*/
	464	if (tick_broadcast_reprogram())
	465	goto again;
	466	}
	467	spin_unlock(&tick_broadcast_lock);
468	}
469
470	/*
471	* Powerstate information: The system enters/leaves a state, where
472	* affected devices might stop
473	*/
474	void tick_broadcast_oneshot_control(unsigned long reason)
475	{
476	struct clock_event_device bc, dev;
477	struct tick_device *td;
478	unsigned long flags;
479	int cpu;
480
481	spin_lock_irqsave(&tick_broadcast_lock, flags);
482
483	/*
484	* Periodic mode does not care about the enter/exit of power
485	* states
486	*/
487	if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC)
488	goto out;
489
490	bc = tick_broadcast_device.evtdev;
491	cpu = smp_processor_id();
492	td = &per_cpu(tick_cpu_device, cpu);
493	dev = td->evtdev;
494
495	if (!(dev->features & CLOCK_EVT_FEAT_C3STOP))
496	goto out;
497
498	if (reason == CLOCK_EVT_NOTIFY_BROADCAST_ENTER) {
499	if (!cpu_isset(cpu, tick_broadcast_oneshot_mask)) {
500	cpu_set(cpu, tick_broadcast_oneshot_mask);
501	clockevents_set_mode(dev, CLOCK_EVT_MODE_SHUTDOWN);
502	if (dev->next_event.tv64 < bc->next_event.tv64)
503	tick_broadcast_set_event(dev->next_event, 1);
504	}
505	} else {
506	if (cpu_isset(cpu, tick_broadcast_oneshot_mask)) {
507	cpu_clear(cpu, tick_broadcast_oneshot_mask);
508	clockevents_set_mode(dev, CLOCK_EVT_MODE_ONESHOT);
509	if (dev->next_event.tv64 != KTIME_MAX)
510	tick_program_event(dev->next_event, 1);
511	}
512	}
513
514	out:
515	spin_unlock_irqrestore(&tick_broadcast_lock, flags);
516	}
517
5590a536 TG	518	/*
	519	* Reset the one shot broadcast for a cpu
	520	*
	521	* Called with tick_broadcast_lock held
	522	*/
	523	static void tick_broadcast_clear_oneshot(int cpu)
	524	{
	525	cpu_clear(cpu, tick_broadcast_oneshot_mask);
	526	}
	527
79bf2bb3 TG	528	/**
	529	* tick_broadcast_setup_highres - setup the broadcast device for highres
	530	*/
	531	void tick_broadcast_setup_oneshot(struct clock_event_device *bc)
	532	{
	533	if (bc->mode != CLOCK_EVT_MODE_ONESHOT) {
	534	bc->event_handler = tick_handle_oneshot_broadcast;
	535	clockevents_set_mode(bc, CLOCK_EVT_MODE_ONESHOT);
	536	bc->next_event.tv64 = KTIME_MAX;
	537	}
	538	}
	539
	540	/*
	541	* Select oneshot operating mode for the broadcast device
	542	*/
	543	void tick_broadcast_switch_to_oneshot(void)
	544	{
	545	struct clock_event_device *bc;
	546	unsigned long flags;
	547
	548	spin_lock_irqsave(&tick_broadcast_lock, flags);
	549
	550	tick_broadcast_device.mode = TICKDEV_MODE_ONESHOT;
	551	bc = tick_broadcast_device.evtdev;
	552	if (bc)
	553	tick_broadcast_setup_oneshot(bc);
	554	spin_unlock_irqrestore(&tick_broadcast_lock, flags);
	555	}
	556
	557
	558	/*
	559	* Remove a dead CPU from broadcasting
	560	*/
	561	void tick_shutdown_broadcast_oneshot(unsigned int *cpup)
	562	{
79bf2bb3 TG	563	unsigned long flags;
	564	unsigned int cpu = *cpup;
	565
	566	spin_lock_irqsave(&tick_broadcast_lock, flags);
	567
31d9b393 TG	568	/*
	569	* Clear the broadcast mask flag for the dead cpu, but do not
	570	* stop the broadcast device!
	571	*/
79bf2bb3 TG	572	cpu_clear(cpu, tick_broadcast_oneshot_mask);
79bf2bb3 TG	573
79bf2bb3 TG	574	spin_unlock_irqrestore(&tick_broadcast_lock, flags);
	575	}
	576
	577	#endif