timer.c

linux 内核源代码

	.stop =		snd_timer_s_stop
};

static void snd_timer_free_system(struct snd_timer *timer)
{
	kfree(timer->private_data);
}

static int snd_timer_register_system(void)
{
	struct snd_timer *timer;
	struct snd_timer_system_private *priv;
	int err;

	err = snd_timer_global_new("system", SNDRV_TIMER_GLOBAL_SYSTEM, &timer);
	if (err < 0)
		return err;
	strcpy(timer->name, "system timer");
	timer->hw = snd_timer_system;
	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
	if (priv == NULL) {
		snd_timer_free(timer);
		return -ENOMEM;
	}
	init_timer(&priv->tlist);
	priv->tlist.function = snd_timer_s_function;
	priv->tlist.data = (unsigned long) timer;
	timer->private_data = priv;
	timer->private_free = snd_timer_free_system;
	return snd_timer_global_register(timer);
}

#ifdef CONFIG_PROC_FS
/*
 *  Info interface
 */

static void snd_timer_proc_read(struct snd_info_entry *entry,
				struct snd_info_buffer *buffer)
{
	struct snd_timer *timer;
	struct snd_timer_instance *ti;

	mutex_lock(&register_mutex);
	list_for_each_entry(timer, &snd_timer_list, device_list) {
		switch (timer->tmr_class) {
		case SNDRV_TIMER_CLASS_GLOBAL:
			snd_iprintf(buffer, "G%i: ", timer->tmr_device);
			break;
		case SNDRV_TIMER_CLASS_CARD:
			snd_iprintf(buffer, "C%i-%i: ",
				    timer->card->number, timer->tmr_device);
			break;
		case SNDRV_TIMER_CLASS_PCM:
			snd_iprintf(buffer, "P%i-%i-%i: ", timer->card->number,
				    timer->tmr_device, timer->tmr_subdevice);
			break;
		default:
			snd_iprintf(buffer, "?%i-%i-%i-%i: ", timer->tmr_class,
				    timer->card ? timer->card->number : -1,
				    timer->tmr_device, timer->tmr_subdevice);
		}
		snd_iprintf(buffer, "%s :", timer->name);
		if (timer->hw.resolution)
			snd_iprintf(buffer, " %lu.%03luus (%lu ticks)",
				    timer->hw.resolution / 1000,
				    timer->hw.resolution % 1000,
				    timer->hw.ticks);
		if (timer->hw.flags & SNDRV_TIMER_HW_SLAVE)
			snd_iprintf(buffer, " SLAVE");
		snd_iprintf(buffer, "\n");
		list_for_each_entry(ti, &timer->open_list_head, open_list)
			snd_iprintf(buffer, "  Client %s : %s\n",
				    ti->owner ? ti->owner : "unknown",
				    ti->flags & (SNDRV_TIMER_IFLG_START |
						 SNDRV_TIMER_IFLG_RUNNING)
				    ? "running" : "stopped");
	}
	mutex_unlock(&register_mutex);
}

static struct snd_info_entry *snd_timer_proc_entry;

static void __init snd_timer_proc_init(void)
{
	struct snd_info_entry *entry;

	entry = snd_info_create_module_entry(THIS_MODULE, "timers", NULL);
	if (entry != NULL) {
		entry->c.text.read = snd_timer_proc_read;
		if (snd_info_register(entry) < 0) {
			snd_info_free_entry(entry);
			entry = NULL;
		}
	}
	snd_timer_proc_entry = entry;
}

static void __exit snd_timer_proc_done(void)
{
	snd_info_free_entry(snd_timer_proc_entry);
}
#else /* !CONFIG_PROC_FS */
#define snd_timer_proc_init()
#define snd_timer_proc_done()
#endif

/*
 *  USER SPACE interface
 */

static void snd_timer_user_interrupt(struct snd_timer_instance *timeri,
				     unsigned long resolution,
				     unsigned long ticks)
{
	struct snd_timer_user *tu = timeri->callback_data;
	struct snd_timer_read *r;
	int prev;

	spin_lock(&tu->qlock);
	if (tu->qused > 0) {
		prev = tu->qtail == 0 ? tu->queue_size - 1 : tu->qtail - 1;
		r = &tu->queue[prev];
		if (r->resolution == resolution) {
			r->ticks += ticks;
			goto __wake;
		}
	}
	if (tu->qused >= tu->queue_size) {
		tu->overrun++;
	} else {
		r = &tu->queue[tu->qtail++];
		tu->qtail %= tu->queue_size;
		r->resolution = resolution;
		r->ticks = ticks;
		tu->qused++;
	}
      __wake:
	spin_unlock(&tu->qlock);
	kill_fasync(&tu->fasync, SIGIO, POLL_IN);
	wake_up(&tu->qchange_sleep);
}

static void snd_timer_user_append_to_tqueue(struct snd_timer_user *tu,
					    struct snd_timer_tread *tread)
{
	if (tu->qused >= tu->queue_size) {
		tu->overrun++;
	} else {
		memcpy(&tu->tqueue[tu->qtail++], tread, sizeof(*tread));
		tu->qtail %= tu->queue_size;
		tu->qused++;
	}
}

static void snd_timer_user_ccallback(struct snd_timer_instance *timeri,
				     int event,
				     struct timespec *tstamp,
				     unsigned long resolution)
{
	struct snd_timer_user *tu = timeri->callback_data;
	struct snd_timer_tread r1;

	if (event >= SNDRV_TIMER_EVENT_START &&
	    event <= SNDRV_TIMER_EVENT_PAUSE)
		tu->tstamp = *tstamp;
	if ((tu->filter & (1 << event)) == 0 || !tu->tread)
		return;
	r1.event = event;
	r1.tstamp = *tstamp;
	r1.val = resolution;
	spin_lock(&tu->qlock);
	snd_timer_user_append_to_tqueue(tu, &r1);
	spin_unlock(&tu->qlock);
	kill_fasync(&tu->fasync, SIGIO, POLL_IN);
	wake_up(&tu->qchange_sleep);
}

static void snd_timer_user_tinterrupt(struct snd_timer_instance *timeri,
				      unsigned long resolution,
				      unsigned long ticks)
{
	struct snd_timer_user *tu = timeri->callback_data;
	struct snd_timer_tread *r, r1;
	struct timespec tstamp;
	int prev, append = 0;

	memset(&tstamp, 0, sizeof(tstamp));
	spin_lock(&tu->qlock);
	if ((tu->filter & ((1 << SNDRV_TIMER_EVENT_RESOLUTION) |
			   (1 << SNDRV_TIMER_EVENT_TICK))) == 0) {
		spin_unlock(&tu->qlock);
		return;
	}
	if (tu->last_resolution != resolution || ticks > 0)
		getnstimeofday(&tstamp);
	if ((tu->filter & (1 << SNDRV_TIMER_EVENT_RESOLUTION)) &&
	    tu->last_resolution != resolution) {
		r1.event = SNDRV_TIMER_EVENT_RESOLUTION;
		r1.tstamp = tstamp;
		r1.val = resolution;
		snd_timer_user_append_to_tqueue(tu, &r1);
		tu->last_resolution = resolution;
		append++;
	}
	if ((tu->filter & (1 << SNDRV_TIMER_EVENT_TICK)) == 0)
		goto __wake;
	if (ticks == 0)
		goto __wake;
	if (tu->qused > 0) {
		prev = tu->qtail == 0 ? tu->queue_size - 1 : tu->qtail - 1;
		r = &tu->tqueue[prev];
		if (r->event == SNDRV_TIMER_EVENT_TICK) {
			r->tstamp = tstamp;
			r->val += ticks;
			append++;
			goto __wake;
		}
	}
	r1.event = SNDRV_TIMER_EVENT_TICK;
	r1.tstamp = tstamp;
	r1.val = ticks;
	snd_timer_user_append_to_tqueue(tu, &r1);
	append++;
      __wake:
	spin_unlock(&tu->qlock);
	if (append == 0)
		return;
	kill_fasync(&tu->fasync, SIGIO, POLL_IN);
	wake_up(&tu->qchange_sleep);
}

static int snd_timer_user_open(struct inode *inode, struct file *file)
{
	struct snd_timer_user *tu;

	tu = kzalloc(sizeof(*tu), GFP_KERNEL);
	if (tu == NULL)
		return -ENOMEM;
	spin_lock_init(&tu->qlock);
	init_waitqueue_head(&tu->qchange_sleep);
	mutex_init(&tu->tread_sem);
	tu->ticks = 1;
	tu->queue_size = 128;
	tu->queue = kmalloc(tu->queue_size * sizeof(struct snd_timer_read),
			    GFP_KERNEL);
	if (tu->queue == NULL) {
		kfree(tu);
		return -ENOMEM;
	}
	file->private_data = tu;
	return 0;
}

static int snd_timer_user_release(struct inode *inode, struct file *file)
{
	struct snd_timer_user *tu;

	if (file->private_data) {
		tu = file->private_data;
		file->private_data = NULL;
		fasync_helper(-1, file, 0, &tu->fasync);
		if (tu->timeri)
			snd_timer_close(tu->timeri);
		kfree(tu->queue);
		kfree(tu->tqueue);
		kfree(tu);
	}
	return 0;
}

static void snd_timer_user_zero_id(struct snd_timer_id *id)
{
	id->dev_class = SNDRV_TIMER_CLASS_NONE;
	id->dev_sclass = SNDRV_TIMER_SCLASS_NONE;
	id->card = -1;
	id->device = -1;
	id->subdevice = -1;
}

static void snd_timer_user_copy_id(struct snd_timer_id *id, struct snd_timer *timer)
{
	id->dev_class = timer->tmr_class;
	id->dev_sclass = SNDRV_TIMER_SCLASS_NONE;
	id->card = timer->card ? timer->card->number : -1;
	id->device = timer->tmr_device;
	id->subdevice = timer->tmr_subdevice;
}

static int snd_timer_user_next_device(struct snd_timer_id __user *_tid)
{
	struct snd_timer_id id;
	struct snd_timer *timer;
	struct list_head *p;

	if (copy_from_user(&id, _tid, sizeof(id)))
		return -EFAULT;
	mutex_lock(&register_mutex);
	if (id.dev_class < 0) {		/* first item */
		if (list_empty(&snd_timer_list))
			snd_timer_user_zero_id(&id);
		else {
			timer = list_entry(snd_timer_list.next,
					   struct snd_timer, device_list);
			snd_timer_user_copy_id(&id, timer);
		}
	} else {
		switch (id.dev_class) {
		case SNDRV_TIMER_CLASS_GLOBAL:
			id.device = id.device < 0 ? 0 : id.device + 1;
			list_for_each(p, &snd_timer_list) {
				timer = list_entry(p, struct snd_timer, device_list);
				if (timer->tmr_class > SNDRV_TIMER_CLASS_GLOBAL) {
					snd_timer_user_copy_id(&id, timer);
					break;
				}
				if (timer->tmr_device >= id.device) {
					snd_timer_user_copy_id(&id, timer);
					break;
				}
			}
			if (p == &snd_timer_list)
				snd_timer_user_zero_id(&id);
			break;
		case SNDRV_TIMER_CLASS_CARD:
		case SNDRV_TIMER_CLASS_PCM:
			if (id.card < 0) {
				id.card = 0;
			} else {
				if (id.card < 0) {
					id.card = 0;
				} else {
					if (id.device < 0) {
						id.device = 0;
					} else {
						if (id.subdevice < 0) {
							id.subdevice = 0;
						} else {
							id.subdevice++;
						}
					}
				}
			}
			list_for_each(p, &snd_timer_list) {
				timer = list_entry(p, struct snd_timer, device_list);
				if (timer->tmr_class > id.dev_class) {
					snd_timer_user_copy_id(&id, timer);
					break;
				}
				if (timer->tmr_class < id.dev_class)
					continue;
				if (timer->card->number > id.card) {
					snd_timer_user_copy_id(&id, timer);
					break;
				}
				if (timer->card->number < id.card)
					continue;
				if (timer->tmr_device > id.device) {
					snd_timer_user_copy_id(&id, timer);
					break;
				}
				if (timer->tmr_device < id.device)
					continue;
				if (timer->tmr_subdevice > id.subdevice) {
					snd_timer_user_copy_id(&id, timer);
					break;
				}
				if (timer->tmr_subdevice < id.subdevice)
					continue;
				snd_timer_user_copy_id(&id, timer);
				break;
			}
			if (p == &snd_timer_list)
				snd_timer_user_zero_id(&id);
			break;
		default:
			snd_timer_user_zero_id(&id);
		}
	}
	mutex_unlock(&register_mutex);
	if (copy_to_user(_tid, &id, sizeof(*_tid)))
		return -EFAULT;
	return 0;
}

static int snd_timer_user_ginfo(struct file *file,
				struct snd_timer_ginfo __user *_ginfo)
{
	struct snd_timer_ginfo *ginfo;
	struct snd_timer_id tid;
	struct snd_timer *t;
	struct list_head *p;
	int err = 0;

	ginfo = kmalloc(sizeof(*ginfo), GFP_KERNEL);
	if (! ginfo)
		return -ENOMEM;
	if (copy_from_user(ginfo, _ginfo, sizeof(*ginfo))) {
		kfree(ginfo);
		return -EFAULT;
	}
	tid = ginfo->tid;
	memset(ginfo, 0, sizeof(*ginfo));
	ginfo->tid = tid;
	mutex_lock(&register_mutex);
	t = snd_timer_find(&tid);
	if (t != NULL) {
		ginfo->card = t->card ? t->card->number : -1;
		if (t->hw.flags & SNDRV_TIMER_HW_SLAVE)
			ginfo->flags |= SNDRV_TIMER_FLG_SLAVE;
		strlcpy(ginfo->id, t->id, sizeof(ginfo->id));
		strlcpy(ginfo->name, t->name, sizeof(ginfo->name));
		ginfo->resolution = t->hw.resolution;
		if (t->hw.resolution_min > 0) {
			ginfo->resolution_min = t->hw.resolution_min;
			ginfo->resolution_max = t->hw.resolution_max;
		}
		list_for_each(p, &t->open_list_head) {
			ginfo->clients++;
		}
	} else {
		err = -ENODEV;
	}
	mutex_unlock(&register_mutex);
	if (err >= 0 && copy_to_user(_ginfo, ginfo, sizeof(*ginfo)))
		err = -EFAULT;
	kfree(ginfo);
	return err;
}

static int snd_timer_user_gparams(struct file *file,
				  struct snd_timer_gparams __user *_gparams)
{
	struct snd_timer_gparams gparams;
	struct snd_timer *t;
	int err;

	if (copy_from_user(&gparams, _gparams, sizeof(gparams)))
		return -EFAULT;
	mutex_lock(&register_mutex);
	t = snd_timer_find(&gparams.tid);
	if (!t) {
		err = -ENODEV;
		goto _error;
	}
	if (!list_empty(&t->open_list_head)) {
		err = -EBUSY;
		goto _error;
	}
	if (!t->hw.set_period) {
		err = -ENOSYS;
		goto _error;
	}
	err = t->hw.set_period(t, gparams.period_num, gparams.period_den);
_error:
	mutex_unlock(&register_mutex);
	return err;
}

static int snd_timer_user_gstatus(struct file *file,
				  struct snd_timer_gstatus __user *_gstatus)
{
	struct snd_timer_gstatus gstatus;
	struct snd_timer_id tid;
	struct snd_timer *t;
	int err = 0;

	if (copy_from_user(&gstatus, _gstatus, sizeof(gstatus)))
		return -EFAULT;
	tid = gstatus.tid;
	memset(&gstatus, 0, sizeof(gstatus));
	gstatus.tid = tid;
	mutex_lock(&register_mutex);
	t = snd_timer_find(&tid);
	if (t != NULL) {
		if (t->hw.c_resolution)
			gstatus.resolution = t->hw.c_resolution(t);
		else
			gstatus.resolution = t->hw.resolution;
		if (t->hw.precise_resolution) {
			t->hw.precise_resolution(t, &gstatus.resolution_num,
						 &gstatus.resolution_den);
		} else {
			gstatus.resolution_num = gstatus.resolution;
			gstatus.resolution_den = 1000000000uL;
		}
	} else {
		err = -ENODEV;
	}
	mutex_unlock(&register_mutex);
	if (err >= 0 && copy_to_user(_gstatus, &gstatus, sizeof(gstatus)))
		err = -EFAULT;
	return err;
}