[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 &&
	     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
 */
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)
{
	tick_do_periodic_broadcast();

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

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

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

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

	spin_lock_irqsave(&tick_broadcast_lock, flags);

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

	/*
	 * Is the device not affected by the powerstate ?
	 */
	if (!dev || !(dev->features & CLOCK_EVT_FEAT_C3STOP))
		goto out;

	/*
	 * Defect device ?
	 */
	if (!tick_device_is_functional(dev)) {
		/*
		 * AMD C1E wreckage fixup:
		 *
		 * Device was registered functional in the first
		 * place. Now the secondary CPU detected the C1E
		 * misfeature and notifies us to fix it up
		 */
		if (*reason != CLOCK_EVT_NOTIFY_BROADCAST_FORCE)
			goto out;
	}

	switch (*reason) {
	case CLOCK_EVT_NOTIFY_BROADCAST_ON:
	case CLOCK_EVT_NOTIFY_BROADCAST_FORCE:
		if (!cpu_isset(cpu, tick_broadcast_mask)) {
			cpu_set(cpu, tick_broadcast_mask);
			if (td->mode == TICKDEV_MODE_PERIODIC)
				clockevents_set_mode(dev,
						     CLOCK_EVT_MODE_SHUTDOWN);
		}
		break;
	case CLOCK_EVT_NOTIFY_BROADCAST_OFF:
		if (cpu_isset(cpu, tick_broadcast_mask)) {
			cpu_clear(cpu, tick_broadcast_mask);
			if (td->mode == TICKDEV_MODE_PERIODIC)
				tick_setup_periodic(dev, 0);
		}
		break;
	}

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

/*
 * Powerstate information: The system enters/leaves a state, where
 * affected devices might stop.
 */
void tick_broadcast_on_off(unsigned long reason, int *oncpu)
{
	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)
{
	clockevents_set_mode(bc, CLOCK_EVT_MODE_ONESHOT);
	return 0;
}

/*
 * 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)
{
	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	{
4a93232d VP	67	if ((tick_broadcast_device.evtdev &&
	68	tick_broadcast_device.evtdev->rating >= dev->rating) \|\|
	69	(dev->features & CLOCK_EVT_FEAT_C3STOP))
f8381cba TG	70	return 0;
	71
	72	clockevents_exchange_device(NULL, dev);
	73	tick_broadcast_device.evtdev = dev;
	74	if (!cpus_empty(tick_broadcast_mask))
	75	tick_broadcast_start_periodic(dev);
	76	return 1;
	77	}
	78
	79	/*
	80	* Check, if the device is the broadcast device
	81	*/
	82	int tick_is_broadcast_device(struct clock_event_device *dev)
	83	{
	84	return (dev && tick_broadcast_device.evtdev == dev);
	85	}
	86
	87	/*
	88	* Check, if the device is disfunctional and a place holder, which
	89	* needs to be handled by the broadcast device.
	90	*/
	91	int tick_device_uses_broadcast(struct clock_event_device *dev, int cpu)
	92	{
	93	unsigned long flags;
	94	int ret = 0;
	95
	96	spin_lock_irqsave(&tick_broadcast_lock, flags);
	97
	98	/*
	99	* Devices might be registered with both periodic and oneshot
	100	* mode disabled. This signals, that the device needs to be
	101	* operated from the broadcast device and is a placeholder for
	102	* the cpu local device.
	103	*/
	104	if (!tick_device_is_functional(dev)) {
	105	dev->event_handler = tick_handle_periodic;
	106	cpu_set(cpu, tick_broadcast_mask);
	107	tick_broadcast_start_periodic(tick_broadcast_device.evtdev);
	108	ret = 1;
5590a536 TG	109	} else {
	110	/*
	111	* When the new device is not affected by the stop
	112	* feature and the cpu is marked in the broadcast mask
	113	* then clear the broadcast bit.
	114	*/
	115	if (!(dev->features & CLOCK_EVT_FEAT_C3STOP)) {
	116	int cpu = smp_processor_id();
f8381cba	117
5590a536 TG	118	cpu_clear(cpu, tick_broadcast_mask);
	119	tick_broadcast_clear_oneshot(cpu);
	120	}
	121	}
f8381cba TG	122	spin_unlock_irqrestore(&tick_broadcast_lock, flags);
	123	return ret;
	124	}
	125
	126	/*
	127	* Broadcast the event to the cpus, which are set in the mask
	128	*/
	129	int tick_do_broadcast(cpumask_t mask)
	130	{
	131	int ret = 0, cpu = smp_processor_id();
	132	struct tick_device *td;
	133
	134	/*
	135	* Check, if the current cpu is in the mask
	136	*/
	137	if (cpu_isset(cpu, mask)) {
	138	cpu_clear(cpu, mask);
	139	td = &per_cpu(tick_cpu_device, cpu);
	140	td->evtdev->event_handler(td->evtdev);
	141	ret = 1;
	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);
	154	ret = 1;
	155	}
	156	return ret;
	157	}
	158
	159	/*
	160	* Periodic broadcast:
	161	* - invoke the broadcast handlers
	162	*/
	163	static void tick_do_periodic_broadcast(void)
	164	{
	165	cpumask_t mask;
	166
	167	spin_lock(&tick_broadcast_lock);
	168
	169	cpus_and(mask, cpu_online_map, tick_broadcast_mask);
	170	tick_do_broadcast(mask);
	171
	172	spin_unlock(&tick_broadcast_lock);
	173	}
	174
	175	/*
	176	* Event handler for periodic broadcast ticks
	177	*/
	178	static void tick_handle_periodic_broadcast(struct clock_event_device *dev)
	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
	190	* periodic mode:
	191	*/
	192	for (;;) {
	193	ktime_t next = ktime_add(dev->next_event, tick_period);
	194
	195	if (!clockevents_program_event(dev, next, ktime_get()))
	196	return;
	197	tick_do_periodic_broadcast();
	198	}
	199	}
	200
	201	/*
	202	* Powerstate information: The system enters/leaves a state, where
	203	* affected devices might stop
	204	*/
	205	static void tick_do_broadcast_on_off(void *why)
	206	{
	207	struct clock_event_device bc, dev;
	208	struct tick_device *td;
	209	unsigned long flags, *reason = why;
	210	int cpu;
	211
	212	spin_lock_irqsave(&tick_broadcast_lock, flags);
	213
	214	cpu = smp_processor_id();
	215	td = &per_cpu(tick_cpu_device, cpu);
	216	dev = td->evtdev;
	217	bc = tick_broadcast_device.evtdev;
	218
	219	/*
1595f452	220	* Is the device not affected by the powerstate ?
f8381cba	221	*/
1595f452	222	if (!dev \|\| !(dev->features & CLOCK_EVT_FEAT_C3STOP))
f8381cba TG	223	goto out;
f8381cba TG	224
1595f452 TG	225	/*
	226	* Defect device ?
	227	*/
	228	if (!tick_device_is_functional(dev)) {
	229	/*
	230	* AMD C1E wreckage fixup:
	231	*
	232	* Device was registered functional in the first
	233	* place. Now the secondary CPU detected the C1E
	234	* misfeature and notifies us to fix it up
	235	*/
	236	if (*reason != CLOCK_EVT_NOTIFY_BROADCAST_FORCE)
	237	goto out;
	238	}
	239
	240	switch (*reason) {
	241	case CLOCK_EVT_NOTIFY_BROADCAST_ON:
	242	case CLOCK_EVT_NOTIFY_BROADCAST_FORCE:
f8381cba TG	243	if (!cpu_isset(cpu, tick_broadcast_mask)) {
	244	cpu_set(cpu, tick_broadcast_mask);
	245	if (td->mode == TICKDEV_MODE_PERIODIC)
	246	clockevents_set_mode(dev,
	247	CLOCK_EVT_MODE_SHUTDOWN);
	248	}
1595f452 TG	249	break;
1595f452 TG	250	case CLOCK_EVT_NOTIFY_BROADCAST_OFF:
f8381cba TG	251	if (cpu_isset(cpu, tick_broadcast_mask)) {
	252	cpu_clear(cpu, tick_broadcast_mask);
	253	if (td->mode == TICKDEV_MODE_PERIODIC)
	254	tick_setup_periodic(dev, 0);
	255	}
1595f452	256	break;
f8381cba TG	257	}
	258
	259	if (cpus_empty(tick_broadcast_mask))
	260	clockevents_set_mode(bc, CLOCK_EVT_MODE_SHUTDOWN);
	261	else {
	262	if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC)
	263	tick_broadcast_start_periodic(bc);
79bf2bb3 TG	264	else
79bf2bb3 TG	265	tick_broadcast_setup_oneshot(bc);
f8381cba TG	266	}
	267	out:
	268	spin_unlock_irqrestore(&tick_broadcast_lock, flags);
	269	}
	270
	271	/*
	272	* Powerstate information: The system enters/leaves a state, where
	273	* affected devices might stop.
	274	*/
	275	void tick_broadcast_on_off(unsigned long reason, int *oncpu)
	276	{
	277	int cpu = get_cpu();
	278
72fcde96 TG	279	if (!cpu_isset(*oncpu, cpu_online_map)) {
	280	printk(KERN_ERR "tick-braodcast: ignoring broadcast for "
	281	"offline CPU #%d\n", *oncpu);
	282	} else {
	283
	284	if (cpu == *oncpu)
	285	tick_do_broadcast_on_off(&reason);
	286	else
	287	smp_call_function_single(*oncpu,
	288	tick_do_broadcast_on_off,
	289	&reason, 1, 1);
	290	}
f8381cba TG	291	put_cpu();
	292	}
	293
	294	/*
	295	* Set the periodic handler depending on broadcast on/off
	296	*/
	297	void tick_set_periodic_handler(struct clock_event_device *dev, int broadcast)
	298	{
	299	if (!broadcast)
	300	dev->event_handler = tick_handle_periodic;
	301	else
	302	dev->event_handler = tick_handle_periodic_broadcast;
	303	}
	304
	305	/*
	306	* Remove a CPU from broadcasting
	307	*/
	308	void tick_shutdown_broadcast(unsigned int *cpup)
	309	{
	310	struct clock_event_device *bc;
	311	unsigned long flags;
	312	unsigned int cpu = *cpup;
	313
	314	spin_lock_irqsave(&tick_broadcast_lock, flags);
	315
	316	bc = tick_broadcast_device.evtdev;
	317	cpu_clear(cpu, tick_broadcast_mask);
	318
	319	if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC) {
	320	if (bc && cpus_empty(tick_broadcast_mask))
	321	clockevents_set_mode(bc, CLOCK_EVT_MODE_SHUTDOWN);
	322	}
	323
	324	spin_unlock_irqrestore(&tick_broadcast_lock, flags);
	325	}
79bf2bb3	326
6321dd60 TG	327	void tick_suspend_broadcast(void)
	328	{
	329	struct clock_event_device *bc;
	330	unsigned long flags;
	331
	332	spin_lock_irqsave(&tick_broadcast_lock, flags);
	333
	334	bc = tick_broadcast_device.evtdev;
18de5bc4	335	if (bc)
6321dd60 TG	336	clockevents_set_mode(bc, CLOCK_EVT_MODE_SHUTDOWN);
	337
	338	spin_unlock_irqrestore(&tick_broadcast_lock, flags);
	339	}
	340
	341	int tick_resume_broadcast(void)
	342	{
	343	struct clock_event_device *bc;
	344	unsigned long flags;
	345	int broadcast = 0;
	346
	347	spin_lock_irqsave(&tick_broadcast_lock, flags);
	348
	349	bc = tick_broadcast_device.evtdev;
6321dd60	350
cd05a1f8	351	if (bc) {
18de5bc4 TG	352	clockevents_set_mode(bc, CLOCK_EVT_MODE_RESUME);
18de5bc4 TG	353
cd05a1f8 TG	354	switch (tick_broadcast_device.mode) {
	355	case TICKDEV_MODE_PERIODIC:
	356	if(!cpus_empty(tick_broadcast_mask))
	357	tick_broadcast_start_periodic(bc);
	358	broadcast = cpu_isset(smp_processor_id(),
	359	tick_broadcast_mask);
	360	break;
	361	case TICKDEV_MODE_ONESHOT:
	362	broadcast = tick_resume_broadcast_oneshot(bc);
	363	break;
	364	}
6321dd60 TG	365	}
	366	spin_unlock_irqrestore(&tick_broadcast_lock, flags);
	367
	368	return broadcast;
	369	}
	370
	371
79bf2bb3 TG	372	#ifdef CONFIG_TICK_ONESHOT
	373
	374	static cpumask_t tick_broadcast_oneshot_mask;
	375
289f480a IM	376	/*
	377	* Debugging: see timer_list.c
	378	*/
	379	cpumask_t *tick_get_broadcast_oneshot_mask(void)
	380	{
	381	return &tick_broadcast_oneshot_mask;
	382	}
	383
79bf2bb3 TG	384	static int tick_broadcast_set_event(ktime_t expires, int force)
	385	{
	386	struct clock_event_device *bc = tick_broadcast_device.evtdev;
	387	ktime_t now = ktime_get();
	388	int res;
	389
	390	for(;;) {
	391	res = clockevents_program_event(bc, expires, now);
	392	if (!res \|\| !force)
	393	return res;
	394	now = ktime_get();
	395	expires = ktime_add(now, ktime_set(0, bc->min_delta_ns));
	396	}
	397	}
	398
cd05a1f8 TG	399	int tick_resume_broadcast_oneshot(struct clock_event_device *bc)
	400	{
	401	clockevents_set_mode(bc, CLOCK_EVT_MODE_ONESHOT);
b7e113dc	402	return 0;
cd05a1f8 TG	403	}
cd05a1f8 TG	404
79bf2bb3 TG	405	/*
	406	* Reprogram the broadcast device:
	407	*
	408	* Called with tick_broadcast_lock held and interrupts disabled.
	409	*/
	410	static int tick_broadcast_reprogram(void)
	411	{
	412	ktime_t expires = { .tv64 = KTIME_MAX };
	413	struct tick_device *td;
	414	int cpu;
	415
	416	/*
	417	* Find the event which expires next:
	418	*/
	419	for (cpu = first_cpu(tick_broadcast_oneshot_mask); cpu != NR_CPUS;
	420	cpu = next_cpu(cpu, tick_broadcast_oneshot_mask)) {
	421	td = &per_cpu(tick_cpu_device, cpu);
	422	if (td->evtdev->next_event.tv64 < expires.tv64)
	423	expires = td->evtdev->next_event;
	424	}
	425
	426	if (expires.tv64 == KTIME_MAX)
	427	return 0;
	428
	429	return tick_broadcast_set_event(expires, 0);
	430	}
	431
	432	/*
	433	* Handle oneshot mode broadcasting
	434	*/
	435	static void tick_handle_oneshot_broadcast(struct clock_event_device *dev)
	436	{
	437	struct tick_device *td;
	438	cpumask_t mask;
	439	ktime_t now;
	440	int cpu;
	441
	442	spin_lock(&tick_broadcast_lock);
	443	again:
	444	dev->next_event.tv64 = KTIME_MAX;
	445	mask = CPU_MASK_NONE;
	446	now = ktime_get();
	447	/* Find all expired events */
	448	for (cpu = first_cpu(tick_broadcast_oneshot_mask); cpu != NR_CPUS;
	449	cpu = next_cpu(cpu, tick_broadcast_oneshot_mask)) {
	450	td = &per_cpu(tick_cpu_device, cpu);
	451	if (td->evtdev->next_event.tv64 <= now.tv64)
	452	cpu_set(cpu, mask);
	453	}
	454
	455	/*
	456	* Wakeup the cpus which have an expired event. The broadcast
	457	* device is reprogrammed in the return from idle code.
	458	*/
	459	if (!tick_do_broadcast(mask)) {
	460	/*
	461	* The global event did not expire any CPU local
	462	* events. This happens in dyntick mode, as the
	463	* maximum PIT delta is quite small.
	464	*/
	465	if (tick_broadcast_reprogram())
	466	goto again;
	467	}
	468	spin_unlock(&tick_broadcast_lock);
469	}
470
471	/*
472	* Powerstate information: The system enters/leaves a state, where
473	* affected devices might stop
474	*/
475	void tick_broadcast_oneshot_control(unsigned long reason)
476	{
477	struct clock_event_device bc, dev;
478	struct tick_device *td;
479	unsigned long flags;
480	int cpu;
481
482	spin_lock_irqsave(&tick_broadcast_lock, flags);
483
484	/*
485	* Periodic mode does not care about the enter/exit of power
486	* states
487	*/
488	if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC)
489	goto out;
490
491	bc = tick_broadcast_device.evtdev;
492	cpu = smp_processor_id();
493	td = &per_cpu(tick_cpu_device, cpu);
494	dev = td->evtdev;
495
496	if (!(dev->features & CLOCK_EVT_FEAT_C3STOP))
497	goto out;
498
499	if (reason == CLOCK_EVT_NOTIFY_BROADCAST_ENTER) {
500	if (!cpu_isset(cpu, tick_broadcast_oneshot_mask)) {
501	cpu_set(cpu, tick_broadcast_oneshot_mask);
502	clockevents_set_mode(dev, CLOCK_EVT_MODE_SHUTDOWN);
503	if (dev->next_event.tv64 < bc->next_event.tv64)
504	tick_broadcast_set_event(dev->next_event, 1);
505	}
506	} else {
507	if (cpu_isset(cpu, tick_broadcast_oneshot_mask)) {
508	cpu_clear(cpu, tick_broadcast_oneshot_mask);
509	clockevents_set_mode(dev, CLOCK_EVT_MODE_ONESHOT);
510	if (dev->next_event.tv64 != KTIME_MAX)
511	tick_program_event(dev->next_event, 1);
512	}
513	}
514
515	out:
516	spin_unlock_irqrestore(&tick_broadcast_lock, flags);
517	}
518
5590a536 TG	519	/*
	520	* Reset the one shot broadcast for a cpu
	521	*
	522	* Called with tick_broadcast_lock held
	523	*/
	524	static void tick_broadcast_clear_oneshot(int cpu)
	525	{
	526	cpu_clear(cpu, tick_broadcast_oneshot_mask);
	527	}
	528
79bf2bb3 TG	529	/**
	530	* tick_broadcast_setup_highres - setup the broadcast device for highres
	531	*/
	532	void tick_broadcast_setup_oneshot(struct clock_event_device *bc)
	533	{
4a93232d VP	534	bc->event_handler = tick_handle_oneshot_broadcast;
	535	clockevents_set_mode(bc, CLOCK_EVT_MODE_ONESHOT);
	536	bc->next_event.tv64 = KTIME_MAX;
79bf2bb3 TG	537	}
	538
	539	/*
	540	* Select oneshot operating mode for the broadcast device
	541	*/
	542	void tick_broadcast_switch_to_oneshot(void)
	543	{
	544	struct clock_event_device *bc;
	545	unsigned long flags;
	546
	547	spin_lock_irqsave(&tick_broadcast_lock, flags);
	548
	549	tick_broadcast_device.mode = TICKDEV_MODE_ONESHOT;
	550	bc = tick_broadcast_device.evtdev;
	551	if (bc)
	552	tick_broadcast_setup_oneshot(bc);
	553	spin_unlock_irqrestore(&tick_broadcast_lock, flags);
	554	}
	555
	556
	557	/*
	558	* Remove a dead CPU from broadcasting
	559	*/
	560	void tick_shutdown_broadcast_oneshot(unsigned int *cpup)
	561	{
79bf2bb3 TG	562	unsigned long flags;
	563	unsigned int cpu = *cpup;
	564
	565	spin_lock_irqsave(&tick_broadcast_lock, flags);
	566
31d9b393 TG	567	/*
	568	* Clear the broadcast mask flag for the dead cpu, but do not
	569	* stop the broadcast device!
	570	*/
79bf2bb3 TG	571	cpu_clear(cpu, tick_broadcast_oneshot_mask);
79bf2bb3 TG	572
79bf2bb3 TG	573	spin_unlock_irqrestore(&tick_broadcast_lock, flags);
	574	}
	575
	576	#endif