timer.c

来自「Linux Kernel 2.6.9 for OMAP1710」· C语言 代码 · 共 1,895 行 · 第 1/4 页

		if (!keep_flag) {
			spin_lock_irqsave(&slave_active_lock, flags);
			timeri->flags &= ~SNDRV_TIMER_IFLG_RUNNING;
			spin_unlock_irqrestore(&slave_active_lock, flags);
		}
		goto __end;
	}
	timer = timeri->timer;
	if (!timer)
		return -EINVAL;
	spin_lock_irqsave(&timer->lock, flags);
	list_del_init(&timeri->ack_list);
	list_del_init(&timeri->active_list);
	if ((timeri->flags & SNDRV_TIMER_IFLG_RUNNING) &&
	    !(--timer->running)) {
		timer->hw.stop(timer);
		if (timer->flags & SNDRV_TIMER_FLG_RESCHED) {
			timer->flags &= ~SNDRV_TIMER_FLG_RESCHED;
			snd_timer_reschedule(timer, 0);
			if (timer->flags & SNDRV_TIMER_FLG_CHANGE) {
				timer->flags &= ~SNDRV_TIMER_FLG_CHANGE;
				timer->hw.start(timer);
			}
		}
	}
	if (!keep_flag)
		timeri->flags &= ~(SNDRV_TIMER_IFLG_RUNNING|SNDRV_TIMER_IFLG_START);
	spin_unlock_irqrestore(&timer->lock, flags);
      __end:
	if (event != SNDRV_TIMER_EVENT_RESOLUTION)
		snd_timer_notify1(timeri, event);
	return 0;
}

/*
 * stop the timer instance.
 *
 * do not call this from the timer callback!
 */
int snd_timer_stop(snd_timer_instance_t * timeri)
{
	snd_timer_t *timer;
	unsigned long flags;
	int err;

	err = _snd_timer_stop(timeri, 0, SNDRV_TIMER_EVENT_STOP);
	if (err < 0)
		return err;
	timer = timeri->timer;
	spin_lock_irqsave(&timer->lock, flags);
	timeri->cticks = timeri->ticks;
	timeri->pticks = 0;
	spin_unlock_irqrestore(&timer->lock, flags);
	return 0;
}

/*
 * start again..  the tick is kept.
 */
int snd_timer_continue(snd_timer_instance_t * timeri)
{
	snd_timer_t *timer;
	int result = -EINVAL;
	unsigned long flags;

	if (timeri == NULL)
		return result;
	if (timeri->flags & SNDRV_TIMER_IFLG_SLAVE)
		return snd_timer_start_slave(timeri);
	timer = timeri->timer;
	if (! timer)
		return -EINVAL;
	spin_lock_irqsave(&timer->lock, flags);
	if (!timeri->cticks)
		timeri->cticks = 1;
	timeri->pticks = 0;
	result = snd_timer_start1(timer, timeri, timer->sticks);
	spin_unlock_irqrestore(&timer->lock, flags);
	snd_timer_notify1(timeri, SNDRV_TIMER_EVENT_CONTINUE);
	return result;
}

/*
 * pause.. remember the ticks left
 */
int snd_timer_pause(snd_timer_instance_t * timeri)
{
	return _snd_timer_stop(timeri, 0, SNDRV_TIMER_EVENT_PAUSE);
}

/*
 * reschedule the timer
 *
 * start pending instances and check the scheduling ticks.
 * when the scheduling ticks is changed set CHANGE flag to reprogram the timer.
 */
static void snd_timer_reschedule(snd_timer_t * timer, unsigned long ticks_left)
{
	snd_timer_instance_t *ti;
	unsigned long ticks = ~0UL;
	struct list_head *p;

	list_for_each(p, &timer->active_list_head) {
		ti = (snd_timer_instance_t *)list_entry(p, snd_timer_instance_t, active_list);
		if (ti->flags & SNDRV_TIMER_IFLG_START) {
			ti->flags &= ~SNDRV_TIMER_IFLG_START;
			ti->flags |= SNDRV_TIMER_IFLG_RUNNING;
			timer->running++;
		}
		if (ti->flags & SNDRV_TIMER_IFLG_RUNNING) {
			if (ticks > ti->cticks)
				ticks = ti->cticks;
		}
	}
	if (ticks == ~0UL) {
		timer->flags &= ~SNDRV_TIMER_FLG_RESCHED;
		return;
	}
	if (ticks > timer->hw.ticks)
		ticks = timer->hw.ticks;
	if (ticks_left != ticks)
		timer->flags |= SNDRV_TIMER_FLG_CHANGE;
	timer->sticks = ticks;
}

/*
 * timer tasklet
 *
 */
static void snd_timer_tasklet(unsigned long arg)
{
	snd_timer_t *timer = (snd_timer_t *) arg;
	snd_timer_instance_t *ti;
	struct list_head *p;
	unsigned long resolution, ticks;

	spin_lock(&timer->lock);
	/* now process all callbacks */
	while (!list_empty(&timer->sack_list_head)) {
		p = timer->sack_list_head.next;		/* get first item */
		ti = (snd_timer_instance_t *)list_entry(p, snd_timer_instance_t, ack_list);

		/* remove from ack_list and make empty */
		list_del_init(p);
		
		ticks = ti->pticks;
		ti->pticks = 0;
		resolution = ti->resolution;

		ti->flags |= SNDRV_TIMER_IFLG_CALLBACK;
		spin_unlock(&timer->lock);
		if (ti->callback)
			ti->callback(ti, resolution, ticks);
		spin_lock(&timer->lock);
		ti->flags &= ~SNDRV_TIMER_IFLG_CALLBACK;
	}
	spin_unlock(&timer->lock);
}

/*
 * timer interrupt
 *
 * ticks_left is usually equal to timer->sticks.
 *
 */
void snd_timer_interrupt(snd_timer_t * timer, unsigned long ticks_left)
{
	snd_timer_instance_t *ti, *ts;
	unsigned long resolution, ticks;
	struct list_head *p, *q, *n;
	int use_tasklet = 0;

	if (timer == NULL)
		return;

	spin_lock(&timer->lock);

	/* remember the current resolution */
	if (timer->hw.c_resolution)
		resolution = timer->hw.c_resolution(timer);
	else
		resolution = timer->hw.resolution;

	/* loop for all active instances
	 * here we cannot use list_for_each because the active_list of a processed
	 * instance is relinked to done_list_head before callback is called.
	 */
	list_for_each_safe(p, n, &timer->active_list_head) {
		ti = (snd_timer_instance_t *)list_entry(p, snd_timer_instance_t, active_list);
		if (!(ti->flags & SNDRV_TIMER_IFLG_RUNNING))
			continue;
		ti->pticks += ticks_left;
		ti->resolution = resolution;
		if (ti->cticks < ticks_left)
			ti->cticks = 0;
		else
			ti->cticks -= ticks_left;
		if (ti->cticks) /* not expired */
			continue;
		if (ti->flags & SNDRV_TIMER_IFLG_AUTO) {
			ti->cticks = ti->ticks;
		} else {
			ti->flags &= ~SNDRV_TIMER_IFLG_RUNNING;
			if (--timer->running)
				list_del(p);
		}
		if (list_empty(&ti->ack_list)) {
			if ((timer->hw.flags & SNDRV_TIMER_HW_TASKLET) ||
			    (ti->flags & SNDRV_TIMER_IFLG_FAST)) {
				list_add_tail(&ti->ack_list, &timer->ack_list_head);
			} else {
				list_add_tail(&ti->ack_list, &timer->sack_list_head);
			}
		}
		list_for_each(q, &ti->slave_active_head) {
			ts = (snd_timer_instance_t *)list_entry(q, snd_timer_instance_t, active_list);
			ts->pticks = ti->pticks;
			ts->resolution = resolution;
			if (list_empty(&ts->ack_list)) {
				if ((timer->hw.flags & SNDRV_TIMER_HW_TASKLET) ||
				    (ti->flags & SNDRV_TIMER_IFLG_FAST)) {
					list_add_tail(&ts->ack_list, &timer->ack_list_head);
				} else {
					list_add_tail(&ts->ack_list, &timer->sack_list_head);
				}
			}
		}
	}
	if (timer->flags & SNDRV_TIMER_FLG_RESCHED)
		snd_timer_reschedule(timer, ticks_left);
	if (timer->running) {
		if (timer->hw.flags & SNDRV_TIMER_HW_STOP) {
			timer->hw.stop(timer);
			timer->flags |= SNDRV_TIMER_FLG_CHANGE;
		}
		if (!(timer->hw.flags & SNDRV_TIMER_HW_AUTO) ||
		    (timer->flags & SNDRV_TIMER_FLG_CHANGE)) {
			/* restart timer */
			timer->flags &= ~SNDRV_TIMER_FLG_CHANGE;
			timer->hw.start(timer);
		}
	} else {
		timer->hw.stop(timer);
	}

	/* now process all fast callbacks */
	while (!list_empty(&timer->ack_list_head)) {
		p = timer->ack_list_head.next;		/* get first item */
		ti = (snd_timer_instance_t *)list_entry(p, snd_timer_instance_t, ack_list);
		
		/* remove from ack_list and make empty */
		list_del_init(p);
		
		ticks = ti->pticks;
		ti->pticks = 0;

		ti->flags |= SNDRV_TIMER_IFLG_CALLBACK;
		spin_unlock(&timer->lock);
		if (ti->callback)
			ti->callback(ti, resolution, ticks);
		spin_lock(&timer->lock);
		ti->flags &= ~SNDRV_TIMER_IFLG_CALLBACK;
	}

	/* do we have any slow callbacks? */
	use_tasklet = !list_empty(&timer->sack_list_head);
	spin_unlock(&timer->lock);

	if (use_tasklet)
		tasklet_hi_schedule(&timer->task_queue);
}

/*

 */

int snd_timer_new(snd_card_t *card, char *id, snd_timer_id_t *tid, snd_timer_t ** rtimer)
{
	snd_timer_t *timer;
	int err;
	static snd_device_ops_t ops = {
		.dev_free = snd_timer_dev_free,
		.dev_register = snd_timer_dev_register,
		.dev_unregister = snd_timer_dev_unregister
	};

	snd_assert(tid != NULL, return -EINVAL);
	snd_assert(rtimer != NULL, return -EINVAL);
	*rtimer = NULL;
	timer = kcalloc(1, sizeof(*timer), GFP_KERNEL);
	if (timer == NULL)
		return -ENOMEM;
	timer->tmr_class = tid->dev_class;
	timer->card = card;
	timer->tmr_device = tid->device;
	timer->tmr_subdevice = tid->subdevice;
	if (id)
		strlcpy(timer->id, id, sizeof(timer->id));
	INIT_LIST_HEAD(&timer->device_list);
	INIT_LIST_HEAD(&timer->open_list_head);
	INIT_LIST_HEAD(&timer->active_list_head);
	INIT_LIST_HEAD(&timer->ack_list_head);
	INIT_LIST_HEAD(&timer->sack_list_head);
	spin_lock_init(&timer->lock);
	tasklet_init(&timer->task_queue, snd_timer_tasklet, (unsigned long)timer);
	if (card != NULL) {
		if ((err = snd_device_new(card, SNDRV_DEV_TIMER, timer, &ops)) < 0) {
			snd_timer_free(timer);
			return err;
		}
	}
	*rtimer = timer;
	return 0;
}

static int snd_timer_free(snd_timer_t *timer)
{
	snd_assert(timer != NULL, return -ENXIO);
	if (timer->private_free)
		timer->private_free(timer);
	kfree(timer);
	return 0;
}

int snd_timer_dev_free(snd_device_t *device)
{
	snd_timer_t *timer = device->device_data;
	return snd_timer_free(timer);
}

int snd_timer_dev_register(snd_device_t *dev)
{
	snd_timer_t *timer = dev->device_data;
	snd_timer_t *timer1;
	struct list_head *p;

	snd_assert(timer != NULL && timer->hw.start != NULL && timer->hw.stop != NULL, return -ENXIO);
	if (!(timer->hw.flags & SNDRV_TIMER_HW_SLAVE) &&
	    !timer->hw.resolution && timer->hw.c_resolution == NULL)
	    	return -EINVAL;

	down(&register_mutex);
	list_for_each(p, &snd_timer_list) {
		timer1 = (snd_timer_t *)list_entry(p, snd_timer_t, device_list);
		if (timer1->tmr_class > timer->tmr_class)
			break;
		if (timer1->tmr_class < timer->tmr_class)
			continue;
		if (timer1->card && timer->card) {
			if (timer1->card->number > timer->card->number)
				break;
			if (timer1->card->number < timer->card->number)
				continue;
		}
		if (timer1->tmr_device > timer->tmr_device)
			break;
		if (timer1->tmr_device < timer->tmr_device)
			continue;
		if (timer1->tmr_subdevice > timer->tmr_subdevice)
			break;
		if (timer1->tmr_subdevice < timer->tmr_subdevice)
			continue;
		/* conflicts.. */
		up(&register_mutex);
		return -EBUSY;
	}
	list_add_tail(&timer->device_list, p);
	up(&register_mutex);
	return 0;
}

int snd_timer_unregister(snd_timer_t *timer)
{
	struct list_head *p, *n;
	snd_timer_instance_t *ti;

	snd_assert(timer != NULL, return -ENXIO);
	down(&register_mutex);
	if (! list_empty(&timer->open_list_head)) {
		snd_printk(KERN_WARNING "timer 0x%lx is busy?\n", (long)timer);
		list_for_each_safe(p, n, &timer->open_list_head) {
			list_del_init(p);
			ti = (snd_timer_instance_t *)list_entry(p, snd_timer_instance_t, open_list);
			ti->timer = NULL;
		}
	}
	list_del(&timer->device_list);
	up(&register_mutex);
	return snd_timer_free(timer);
}

static int snd_timer_dev_unregister(snd_device_t *device)
{
	snd_timer_t *timer = device->device_data;
	return snd_timer_unregister(timer);
}

void snd_timer_notify(snd_timer_t *timer, enum sndrv_timer_event event, struct timespec *tstamp)
{
	unsigned long flags;
	unsigned long resolution = 0;
	snd_timer_instance_t *ti, *ts;
	struct list_head *p, *n;

	snd_runtime_check(timer->hw.flags & SNDRV_TIMER_HW_SLAVE, return);	
	snd_assert(event >= SNDRV_TIMER_EVENT_MSTART && event <= SNDRV_TIMER_EVENT_MPAUSE, return);
	spin_lock_irqsave(&timer->lock, flags);
	if (event == SNDRV_TIMER_EVENT_MSTART || event == SNDRV_TIMER_EVENT_MCONTINUE) {
		if (timer->hw.c_resolution)
			resolution = timer->hw.c_resolution(timer);
		else
			resolution = timer->hw.resolution;
	}
	list_for_each(p, &timer->active_list_head) {
		ti = (snd_timer_instance_t *)list_entry(p, snd_timer_instance_t, active_list);
		if (ti->ccallback)
			ti->ccallback(ti, event, tstamp, resolution);
		list_for_each(n, &ti->slave_active_head) {
			ts = (snd_timer_instance_t *)list_entry(n, snd_timer_instance_t, active_list);
			if (ts->ccallback)
				ts->ccallback(ts, event, tstamp, resolution);
		}
	}
	spin_unlock_irqrestore(&timer->lock, flags);
}

/*
 * exported functions for global timers
 */
int snd_timer_global_new(char *id, int device, snd_timer_t **rtimer)
{
	snd_timer_id_t tid;
	
	tid.dev_class = SNDRV_TIMER_CLASS_GLOBAL;
	tid.dev_sclass = SNDRV_TIMER_SCLASS_NONE;
	tid.card = -1;
	tid.device = device;
	tid.subdevice = 0;
	return snd_timer_new(NULL, id, &tid, rtimer);
}

int snd_timer_global_free(snd_timer_t *timer)
{
	return snd_timer_free(timer);
}

int snd_timer_global_register(snd_timer_t *timer)
{
	snd_device_t dev;

	memset(&dev, 0, sizeof(dev));
	dev.device_data = timer;
	return snd_timer_dev_register(&dev);
}

int snd_timer_global_unregister(snd_timer_t *timer)
{
	return snd_timer_unregister(timer);
}

/* 
 *  System timer
 */

struct snd_timer_system_private {
	struct timer_list tlist;
	struct timer * timer;
	unsigned long last_expires;
	unsigned long last_jiffies;
	unsigned long correction;
};

unsigned int snd_timer_system_resolution(void)
{