/*
   *  Timers abstract layer

   *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>

   *
   *
   *   This program is free software; you can redistribute it and/or modify
   *   it under the terms of the GNU General Public License as published by
   *   the Free Software Foundation; either version 2 of the License, or
   *   (at your option) any later version.
   *
   *   This program is distributed in the hope that it will be useful,
   *   but WITHOUT ANY WARRANTY; without even the implied warranty of
   *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   *   GNU General Public License for more details.
   *
   *   You should have received a copy of the GNU General Public License
   *   along with this program; if not, write to the Free Software
   *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
   *
   */

  #include <linux/delay.h>
  #include <linux/init.h>

  #include <linux/slab.h>
  #include <linux/time.h>

  #include <linux/mutex.h>

  #include <linux/device.h>

  #include <linux/module.h>

  #include <linux/string.h>

  #include <linux/sched/signal.h>

  #include <sound/core.h>
  #include <sound/timer.h>
  #include <sound/control.h>
  #include <sound/info.h>
  #include <sound/minors.h>
  #include <sound/initval.h>
  #include <linux/kmod.h>

  /* internal flags */
  #define SNDRV_TIMER_IFLG_PAUSED		0x00010000

  #if IS_ENABLED(CONFIG_SND_HRTIMER)

  #define DEFAULT_TIMER_LIMIT 4

  #else
  #define DEFAULT_TIMER_LIMIT 1
  #endif
  
  static int timer_limit = DEFAULT_TIMER_LIMIT;

  static int timer_tstamp_monotonic = 1;

  MODULE_AUTHOR("Jaroslav Kysela <perex@perex.cz>, Takashi Iwai <tiwai@suse.de>");

  MODULE_DESCRIPTION("ALSA timer interface");
  MODULE_LICENSE("GPL");
  module_param(timer_limit, int, 0444);
  MODULE_PARM_DESC(timer_limit, "Maximum global timers in system.");

  module_param(timer_tstamp_monotonic, int, 0444);
  MODULE_PARM_DESC(timer_tstamp_monotonic, "Use posix monotonic clock source for timestamps (default).");

  MODULE_ALIAS_CHARDEV(CONFIG_SND_MAJOR, SNDRV_MINOR_TIMER);
  MODULE_ALIAS("devname:snd/timer");

  struct snd_timer_user {
  	struct snd_timer_instance *timeri;

  	int tread;		/* enhanced read with timestamps and events */

  	unsigned long ticks;
  	unsigned long overrun;
  	int qhead;
  	int qtail;
  	int qused;
  	int queue_size;

  	bool disconnected;

  	struct snd_timer_read *queue;
  	struct snd_timer_tread *tqueue;

  	spinlock_t qlock;
  	unsigned long last_resolution;
  	unsigned int filter;
  	struct timespec tstamp;		/* trigger tstamp */
  	wait_queue_head_t qchange_sleep;
  	struct fasync_struct *fasync;

  	struct mutex ioctl_lock;

  };

  
  /* list of timers */
  static LIST_HEAD(snd_timer_list);
  
  /* list of slave instances */
  static LIST_HEAD(snd_timer_slave_list);
  
  /* lock for slave active lists */
  static DEFINE_SPINLOCK(slave_active_lock);

  static DEFINE_MUTEX(register_mutex);

  static int snd_timer_free(struct snd_timer *timer);
  static int snd_timer_dev_free(struct snd_device *device);
  static int snd_timer_dev_register(struct snd_device *device);

  static int snd_timer_dev_disconnect(struct snd_device *device);

  static void snd_timer_reschedule(struct snd_timer * timer, unsigned long ticks_left);

  
  /*
   * create a timer instance with the given owner string.
   * when timer is not NULL, increments the module counter
   */

  static struct snd_timer_instance *snd_timer_instance_new(char *owner,
  							 struct snd_timer *timer)

  {

  	struct snd_timer_instance *timeri;

  	timeri = kzalloc(sizeof(*timeri), GFP_KERNEL);

  	if (timeri == NULL)
  		return NULL;

  	timeri->owner = kstrdup(owner, GFP_KERNEL);

  	if (! timeri->owner) {
  		kfree(timeri);
  		return NULL;
  	}
  	INIT_LIST_HEAD(&timeri->open_list);
  	INIT_LIST_HEAD(&timeri->active_list);
  	INIT_LIST_HEAD(&timeri->ack_list);
  	INIT_LIST_HEAD(&timeri->slave_list_head);
  	INIT_LIST_HEAD(&timeri->slave_active_head);
  
  	timeri->timer = timer;

  	if (timer && !try_module_get(timer->module)) {

  		kfree(timeri->owner);
  		kfree(timeri);
  		return NULL;
  	}
  
  	return timeri;
  }
  
  /*
   * find a timer instance from the given timer id
   */

  static struct snd_timer *snd_timer_find(struct snd_timer_id *tid)

  {

  	struct snd_timer *timer = NULL;

  	list_for_each_entry(timer, &snd_timer_list, device_list) {

  		if (timer->tmr_class != tid->dev_class)
  			continue;
  		if ((timer->tmr_class == SNDRV_TIMER_CLASS_CARD ||
  		     timer->tmr_class == SNDRV_TIMER_CLASS_PCM) &&
  		    (timer->card == NULL ||
  		     timer->card->number != tid->card))
  			continue;
  		if (timer->tmr_device != tid->device)
  			continue;
  		if (timer->tmr_subdevice != tid->subdevice)
  			continue;
  		return timer;
  	}
  	return NULL;
  }

  #ifdef CONFIG_MODULES

  static void snd_timer_request(struct snd_timer_id *tid)

  {

  	switch (tid->dev_class) {
  	case SNDRV_TIMER_CLASS_GLOBAL:
  		if (tid->device < timer_limit)
  			request_module("snd-timer-%i", tid->device);
  		break;
  	case SNDRV_TIMER_CLASS_CARD:
  	case SNDRV_TIMER_CLASS_PCM:
  		if (tid->card < snd_ecards_limit)
  			request_module("snd-card-%i", tid->card);
  		break;
  	default:
  		break;
  	}
  }
  
  #endif
  
  /*
   * look for a master instance matching with the slave id of the given slave.
   * when found, relink the open_link of the slave.
   *
   * call this with register_mutex down.
   */

  static int snd_timer_check_slave(struct snd_timer_instance *slave)

  {

  	struct snd_timer *timer;
  	struct snd_timer_instance *master;

  
  	/* FIXME: it's really dumb to look up all entries.. */

  	list_for_each_entry(timer, &snd_timer_list, device_list) {
  		list_for_each_entry(master, &timer->open_list_head, open_list) {

  			if (slave->slave_class == master->slave_class &&
  			    slave->slave_id == master->slave_id) {

  				if (master->timer->num_instances >=
  				    master->timer->max_instances)
  					return -EBUSY;

  				list_move_tail(&slave->open_list,
  					       &master->slave_list_head);

  				master->timer->num_instances++;

  				spin_lock_irq(&slave_active_lock);
  				slave->master = master;
  				slave->timer = master->timer;
  				spin_unlock_irq(&slave_active_lock);

  				return 0;

  			}
  		}
  	}

  	return 0;

  }
  
  /*
   * look for slave instances matching with the slave id of the given master.
   * when found, relink the open_link of slaves.
   *
   * call this with register_mutex down.
   */

  static int snd_timer_check_master(struct snd_timer_instance *master)

  {

  	struct snd_timer_instance *slave, *tmp;

  
  	/* check all pending slaves */

  	list_for_each_entry_safe(slave, tmp, &snd_timer_slave_list, open_list) {

  		if (slave->slave_class == master->slave_class &&
  		    slave->slave_id == master->slave_id) {

  			if (master->timer->num_instances >=
  			    master->timer->max_instances)
  				return -EBUSY;

  			list_move_tail(&slave->open_list, &master->slave_list_head);

  			master->timer->num_instances++;

  			spin_lock_irq(&slave_active_lock);

  			spin_lock(&master->timer->lock);

  			slave->master = master;
  			slave->timer = master->timer;
  			if (slave->flags & SNDRV_TIMER_IFLG_RUNNING)

  				list_add_tail(&slave->active_list,
  					      &master->slave_active_head);

  			spin_unlock(&master->timer->lock);

  			spin_unlock_irq(&slave_active_lock);
  		}
  	}

  	return 0;

  }

  static int snd_timer_close_locked(struct snd_timer_instance *timeri);

  /*
   * open a timer instance
   * when opening a master, the slave id must be here given.
   */

  int snd_timer_open(struct snd_timer_instance **ti,
  		   char *owner, struct snd_timer_id *tid,

  		   unsigned int slave_id)
  {

  	struct snd_timer *timer;
  	struct snd_timer_instance *timeri = NULL;

  	int err;

  	if (tid->dev_class == SNDRV_TIMER_CLASS_SLAVE) {
  		/* open a slave instance */
  		if (tid->dev_sclass <= SNDRV_TIMER_SCLASS_NONE ||
  		    tid->dev_sclass > SNDRV_TIMER_SCLASS_OSS_SEQUENCER) {

  			pr_debug("ALSA: timer: invalid slave class %i
  ",
  				 tid->dev_sclass);

  			return -EINVAL;
  		}

  		mutex_lock(&register_mutex);

  		timeri = snd_timer_instance_new(owner, NULL);

  		if (!timeri) {

  			mutex_unlock(&register_mutex);

  			return -ENOMEM;
  		}

  		timeri->slave_class = tid->dev_sclass;
  		timeri->slave_id = tid->device;
  		timeri->flags |= SNDRV_TIMER_IFLG_SLAVE;
  		list_add_tail(&timeri->open_list, &snd_timer_slave_list);

  		err = snd_timer_check_slave(timeri);
  		if (err < 0) {
  			snd_timer_close_locked(timeri);
  			timeri = NULL;
  		}

  		mutex_unlock(&register_mutex);

  		*ti = timeri;

  		return err;

  	}
  
  	/* open a master instance */

  	mutex_lock(&register_mutex);

  	timer = snd_timer_find(tid);

  #ifdef CONFIG_MODULES
  	if (!timer) {

  		mutex_unlock(&register_mutex);

  		snd_timer_request(tid);

  		mutex_lock(&register_mutex);

  		timer = snd_timer_find(tid);
  	}
  #endif

  	if (!timer) {

  		mutex_unlock(&register_mutex);

  		return -ENODEV;
  	}

  	if (!list_empty(&timer->open_list_head)) {
  		timeri = list_entry(timer->open_list_head.next,

  				    struct snd_timer_instance, open_list);

  		if (timeri->flags & SNDRV_TIMER_IFLG_EXCLUSIVE) {

  			mutex_unlock(&register_mutex);

  			return -EBUSY;
  		}
  	}

  	if (timer->num_instances >= timer->max_instances) {
  		mutex_unlock(&register_mutex);
  		return -EBUSY;
  	}

  	timeri = snd_timer_instance_new(owner, timer);
  	if (!timeri) {

  		mutex_unlock(&register_mutex);

  		return -ENOMEM;
  	}

  	/* take a card refcount for safe disconnection */
  	if (timer->card)
  		get_device(&timer->card->card_dev);

  	timeri->slave_class = tid->dev_sclass;
  	timeri->slave_id = slave_id;

  
  	if (list_empty(&timer->open_list_head) && timer->hw.open) {
  		int err = timer->hw.open(timer);
  		if (err) {
  			kfree(timeri->owner);
  			kfree(timeri);
  
  			if (timer->card)
  				put_device(&timer->card->card_dev);
  			module_put(timer->module);
  			mutex_unlock(&register_mutex);
  			return err;
  		}
  	}

  	list_add_tail(&timeri->open_list, &timer->open_list_head);

  	timer->num_instances++;
  	err = snd_timer_check_master(timeri);
  	if (err < 0) {
  		snd_timer_close_locked(timeri);
  		timeri = NULL;
  	}

  	mutex_unlock(&register_mutex);

  	*ti = timeri;

  	return err;

  }

  EXPORT_SYMBOL(snd_timer_open);

  /*
   * close a timer instance

   * call this with register_mutex down.

   */

  static int snd_timer_close_locked(struct snd_timer_instance *timeri)

  {

  	struct snd_timer *timer = NULL;

  	struct snd_timer_instance *slave, *tmp;

  	list_del(&timeri->open_list);

  	/* force to stop the timer */
  	snd_timer_stop(timeri);

  	timer = timeri->timer;
  	if (timer) {

  		timer->num_instances--;

  		/* wait, until the active callback is finished */
  		spin_lock_irq(&timer->lock);
  		while (timeri->flags & SNDRV_TIMER_IFLG_CALLBACK) {
  			spin_unlock_irq(&timer->lock);
  			udelay(10);
  			spin_lock_irq(&timer->lock);
  		}
  		spin_unlock_irq(&timer->lock);

  		/* remove slave links */

  		spin_lock_irq(&slave_active_lock);
  		spin_lock(&timer->lock);

  		list_for_each_entry_safe(slave, tmp, &timeri->slave_list_head,
  					 open_list) {

  			list_move_tail(&slave->open_list, &snd_timer_slave_list);

  			timer->num_instances--;

  			slave->master = NULL;
  			slave->timer = NULL;

  			list_del_init(&slave->ack_list);
  			list_del_init(&slave->active_list);

  		}

  		spin_unlock(&timer->lock);
  		spin_unlock_irq(&slave_active_lock);

  
  		/* slave doesn't need to release timer resources below */
  		if (timeri->flags & SNDRV_TIMER_IFLG_SLAVE)
  			timer = NULL;

  	}

  	if (timeri->private_free)
  		timeri->private_free(timeri);
  	kfree(timeri->owner);
  	kfree(timeri);

  
  	if (timer) {
  		if (list_empty(&timer->open_list_head) && timer->hw.close)
  			timer->hw.close(timer);
  		/* release a card refcount for safe disconnection */
  		if (timer->card)
  			put_device(&timer->card->card_dev);

  		module_put(timer->module);

  	}

  	return 0;
  }

  
  /*
   * close a timer instance
   */
  int snd_timer_close(struct snd_timer_instance *timeri)
  {
  	int err;
  
  	if (snd_BUG_ON(!timeri))
  		return -ENXIO;
  
  	mutex_lock(&register_mutex);
  	err = snd_timer_close_locked(timeri);
  	mutex_unlock(&register_mutex);
  	return err;
  }

  EXPORT_SYMBOL(snd_timer_close);

  unsigned long snd_timer_resolution(struct snd_timer_instance *timeri)

  {

  	struct snd_timer * timer;

  
  	if (timeri == NULL)
  		return 0;

  	timer = timeri->timer;
  	if (timer) {

  		if (timer->hw.c_resolution)
  			return timer->hw.c_resolution(timer);
  		return timer->hw.resolution;
  	}
  	return 0;
  }

  EXPORT_SYMBOL(snd_timer_resolution);

  static void snd_timer_notify1(struct snd_timer_instance *ti, int event)

  {

  	struct snd_timer *timer;

  	unsigned long resolution = 0;

  	struct snd_timer_instance *ts;

  	struct timespec tstamp;

  	if (timer_tstamp_monotonic)

  		ktime_get_ts(&tstamp);

  	else
  		getnstimeofday(&tstamp);

  	if (snd_BUG_ON(event < SNDRV_TIMER_EVENT_START ||
  		       event > SNDRV_TIMER_EVENT_PAUSE))
  		return;

  	if (event == SNDRV_TIMER_EVENT_START ||
  	    event == SNDRV_TIMER_EVENT_CONTINUE)

  		resolution = snd_timer_resolution(ti);
  	if (ti->ccallback)

  		ti->ccallback(ti, event, &tstamp, resolution);

  	if (ti->flags & SNDRV_TIMER_IFLG_SLAVE)
  		return;
  	timer = ti->timer;
  	if (timer == NULL)
  		return;
  	if (timer->hw.flags & SNDRV_TIMER_HW_SLAVE)
  		return;

  	list_for_each_entry(ts, &ti->slave_active_head, active_list)

  		if (ts->ccallback)

  			ts->ccallback(ts, event + 100, &tstamp, resolution);

  }

  /* start/continue a master timer */
  static int snd_timer_start1(struct snd_timer_instance *timeri,
  			    bool start, unsigned long ticks)

  {

  	struct snd_timer *timer;
  	int result;
  	unsigned long flags;
  
  	timer = timeri->timer;
  	if (!timer)
  		return -EINVAL;
  
  	spin_lock_irqsave(&timer->lock, flags);
  	if (timer->card && timer->card->shutdown) {
  		result = -ENODEV;
  		goto unlock;
  	}
  	if (timeri->flags & (SNDRV_TIMER_IFLG_RUNNING |
  			     SNDRV_TIMER_IFLG_START)) {
  		result = -EBUSY;
  		goto unlock;
  	}
  
  	if (start)
  		timeri->ticks = timeri->cticks = ticks;
  	else if (!timeri->cticks)
  		timeri->cticks = 1;
  	timeri->pticks = 0;

  	list_move_tail(&timeri->active_list, &timer->active_list_head);

  	if (timer->running) {
  		if (timer->hw.flags & SNDRV_TIMER_HW_SLAVE)
  			goto __start_now;
  		timer->flags |= SNDRV_TIMER_FLG_RESCHED;
  		timeri->flags |= SNDRV_TIMER_IFLG_START;

  		result = 1; /* delayed start */

  	} else {

  		if (start)
  			timer->sticks = ticks;

  		timer->hw.start(timer);
  	      __start_now:
  		timer->running++;
  		timeri->flags |= SNDRV_TIMER_IFLG_RUNNING;

  		result = 0;

  	}

  	snd_timer_notify1(timeri, start ? SNDRV_TIMER_EVENT_START :
  			  SNDRV_TIMER_EVENT_CONTINUE);
   unlock:
  	spin_unlock_irqrestore(&timer->lock, flags);
  	return result;

  }

  /* start/continue a slave timer */
  static int snd_timer_start_slave(struct snd_timer_instance *timeri,
  				 bool start)

  {
  	unsigned long flags;
  
  	spin_lock_irqsave(&slave_active_lock, flags);

  	if (timeri->flags & SNDRV_TIMER_IFLG_RUNNING) {
  		spin_unlock_irqrestore(&slave_active_lock, flags);
  		return -EBUSY;
  	}

  	timeri->flags |= SNDRV_TIMER_IFLG_RUNNING;

  	if (timeri->master && timeri->timer) {
  		spin_lock(&timeri->timer->lock);

  		list_add_tail(&timeri->active_list,
  			      &timeri->master->slave_active_head);

  		snd_timer_notify1(timeri, start ? SNDRV_TIMER_EVENT_START :
  				  SNDRV_TIMER_EVENT_CONTINUE);

  		spin_unlock(&timeri->timer->lock);
  	}

  	spin_unlock_irqrestore(&slave_active_lock, flags);
  	return 1; /* delayed start */
  }

  /* stop/pause a master timer */
  static int snd_timer_stop1(struct snd_timer_instance *timeri, bool stop)

  {

  	struct snd_timer *timer;

  	int result = 0;

  	unsigned long flags;

  	timer = timeri->timer;
  	if (!timer)
  		return -EINVAL;
  	spin_lock_irqsave(&timer->lock, flags);

  	if (!(timeri->flags & (SNDRV_TIMER_IFLG_RUNNING |
  			       SNDRV_TIMER_IFLG_START))) {

  		result = -EBUSY;
  		goto unlock;

  	}

  	list_del_init(&timeri->ack_list);
  	list_del_init(&timeri->active_list);

  	if (timer->card && timer->card->shutdown)
  		goto unlock;
  	if (stop) {
  		timeri->cticks = timeri->ticks;
  		timeri->pticks = 0;

  	}

  	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);
  			}
  		}
  	}

  	timeri->flags &= ~(SNDRV_TIMER_IFLG_RUNNING | SNDRV_TIMER_IFLG_START);

  	if (stop)
  		timeri->flags &= ~SNDRV_TIMER_IFLG_PAUSED;
  	else
  		timeri->flags |= SNDRV_TIMER_IFLG_PAUSED;

  	snd_timer_notify1(timeri, stop ? SNDRV_TIMER_EVENT_STOP :

  			  SNDRV_TIMER_EVENT_PAUSE);

   unlock:

  	spin_unlock_irqrestore(&timer->lock, flags);

  	return result;
  }
  
  /* stop/pause a slave timer */
  static int snd_timer_stop_slave(struct snd_timer_instance *timeri, bool stop)
  {
  	unsigned long flags;
  
  	spin_lock_irqsave(&slave_active_lock, flags);
  	if (!(timeri->flags & SNDRV_TIMER_IFLG_RUNNING)) {
  		spin_unlock_irqrestore(&slave_active_lock, flags);
  		return -EBUSY;
  	}
  	timeri->flags &= ~SNDRV_TIMER_IFLG_RUNNING;
  	if (timeri->timer) {
  		spin_lock(&timeri->timer->lock);
  		list_del_init(&timeri->ack_list);
  		list_del_init(&timeri->active_list);
  		snd_timer_notify1(timeri, stop ? SNDRV_TIMER_EVENT_STOP :

  				  SNDRV_TIMER_EVENT_PAUSE);

  		spin_unlock(&timeri->timer->lock);
  	}
  	spin_unlock_irqrestore(&slave_active_lock, flags);

  	return 0;
  }
  
  /*

   *  start the timer instance
   */
  int snd_timer_start(struct snd_timer_instance *timeri, unsigned int ticks)
  {
  	if (timeri == NULL || ticks < 1)
  		return -EINVAL;
  	if (timeri->flags & SNDRV_TIMER_IFLG_SLAVE)
  		return snd_timer_start_slave(timeri, true);
  	else
  		return snd_timer_start1(timeri, true, ticks);
  }

  EXPORT_SYMBOL(snd_timer_start);

  
  /*

   * stop the timer instance.
   *
   * do not call this from the timer callback!
   */

  int snd_timer_stop(struct snd_timer_instance *timeri)

  {

  	if (timeri->flags & SNDRV_TIMER_IFLG_SLAVE)
  		return snd_timer_stop_slave(timeri, true);
  	else
  		return snd_timer_stop1(timeri, true);

  }

  EXPORT_SYMBOL(snd_timer_stop);

  
  /*
   * start again..  the tick is kept.
   */

  int snd_timer_continue(struct snd_timer_instance *timeri)

  {

  	/* timer can continue only after pause */
  	if (!(timeri->flags & SNDRV_TIMER_IFLG_PAUSED))
  		return -EINVAL;

  	if (timeri->flags & SNDRV_TIMER_IFLG_SLAVE)

  		return snd_timer_start_slave(timeri, false);
  	else
  		return snd_timer_start1(timeri, false, 0);

  }

  EXPORT_SYMBOL(snd_timer_continue);

  
  /*
   * pause.. remember the ticks left
   */

  int snd_timer_pause(struct snd_timer_instance * timeri)

  {

  	if (timeri->flags & SNDRV_TIMER_IFLG_SLAVE)
  		return snd_timer_stop_slave(timeri, false);
  	else
  		return snd_timer_stop1(timeri, false);

  }

  EXPORT_SYMBOL(snd_timer_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(struct snd_timer * timer, unsigned long ticks_left)

  {

  	struct snd_timer_instance *ti;

  	unsigned long ticks = ~0UL;

  	list_for_each_entry(ti, &timer->active_list_head, 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)
  {

  	struct snd_timer *timer = (struct snd_timer *) arg;
  	struct snd_timer_instance *ti;

  	struct list_head *p;
  	unsigned long resolution, ticks;

  	unsigned long flags;

  	if (timer->card && timer->card->shutdown)
  		return;

  	spin_lock_irqsave(&timer->lock, flags);

  	/* now process all callbacks */
  	while (!list_empty(&timer->sack_list_head)) {
  		p = timer->sack_list_head.next;		/* get first item */

  		ti = list_entry(p, struct snd_timer_instance, 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_irqrestore(&timer->lock, flags);

  }
  
  /*
   * timer interrupt
   *
   * ticks_left is usually equal to timer->sticks.
   *
   */

  void snd_timer_interrupt(struct snd_timer * timer, unsigned long ticks_left)

  {

  	struct snd_timer_instance *ti, *ts, *tmp;

  	unsigned long resolution, ticks;

  	struct list_head *p, *ack_list_head;

  	unsigned long flags;

  	int use_tasklet = 0;
  
  	if (timer == NULL)
  		return;

  	if (timer->card && timer->card->shutdown)
  		return;

  	spin_lock_irqsave(&timer->lock, flags);

  
  	/* 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_entry because the active_list of a

  	 * processed instance is relinked to done_list_head before the callback
  	 * is called.

  	 */

  	list_for_each_entry_safe(ti, tmp, &timer->active_list_head,
  				 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;

  			--timer->running;
  			list_del_init(&ti->active_list);

  		}

  		if ((timer->hw.flags & SNDRV_TIMER_HW_TASKLET) ||
  		    (ti->flags & SNDRV_TIMER_IFLG_FAST))
  			ack_list_head = &timer->ack_list_head;
  		else
  			ack_list_head = &timer->sack_list_head;
  		if (list_empty(&ti->ack_list))
  			list_add_tail(&ti->ack_list, ack_list_head);

  		list_for_each_entry(ts, &ti->slave_active_head, active_list) {

  			ts->pticks = ti->pticks;
  			ts->resolution = resolution;

  			if (list_empty(&ts->ack_list))
  				list_add_tail(&ts->ack_list, ack_list_head);

  		}
  	}
  	if (timer->flags & SNDRV_TIMER_FLG_RESCHED)

  		snd_timer_reschedule(timer, timer->sticks);

  	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 = list_entry(p, struct snd_timer_instance, 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_irqrestore(&timer->lock, flags);

  
  	if (use_tasklet)

  		tasklet_schedule(&timer->task_queue);

  }

  EXPORT_SYMBOL(snd_timer_interrupt);

  
  /*
  
   */

  int snd_timer_new(struct snd_card *card, char *id, struct snd_timer_id *tid,
  		  struct snd_timer **rtimer)

  {

  	struct snd_timer *timer;

  	int err;

  	static struct snd_device_ops ops = {

  		.dev_free = snd_timer_dev_free,
  		.dev_register = snd_timer_dev_register,

  		.dev_disconnect = snd_timer_dev_disconnect,

  	};

  	if (snd_BUG_ON(!tid))
  		return -EINVAL;
  	if (rtimer)
  		*rtimer = NULL;

  	timer = kzalloc(sizeof(*timer), GFP_KERNEL);

  	if (!timer)

  		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));

  	timer->sticks = 1;

  	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);

  	timer->max_instances = 1000; /* default limit per timer */

  	if (card != NULL) {

  		timer->module = card->module;

  		err = snd_device_new(card, SNDRV_DEV_TIMER, timer, &ops);
  		if (err < 0) {

  			snd_timer_free(timer);
  			return err;
  		}
  	}

  	if (rtimer)
  		*rtimer = timer;

  	return 0;
  }

  EXPORT_SYMBOL(snd_timer_new);

  static int snd_timer_free(struct snd_timer *timer)

  {

  	if (!timer)
  		return 0;

  
  	mutex_lock(&register_mutex);
  	if (! list_empty(&timer->open_list_head)) {
  		struct list_head *p, *n;
  		struct snd_timer_instance *ti;

  		pr_warn("ALSA: timer %p is busy?
  ", timer);

  		list_for_each_safe(p, n, &timer->open_list_head) {
  			list_del_init(p);
  			ti = list_entry(p, struct snd_timer_instance, open_list);
  			ti->timer = NULL;
  		}
  	}
  	list_del(&timer->device_list);
  	mutex_unlock(&register_mutex);

  	if (timer->private_free)
  		timer->private_free(timer);
  	kfree(timer);
  	return 0;
  }

  static int snd_timer_dev_free(struct snd_device *device)

  {

  	struct snd_timer *timer = device->device_data;

  	return snd_timer_free(timer);
  }

  static int snd_timer_dev_register(struct snd_device *dev)

  {

  	struct snd_timer *timer = dev->device_data;
  	struct snd_timer *timer1;

  	if (snd_BUG_ON(!timer || !timer->hw.start || !timer->hw.stop))
  		return -ENXIO;

  	if (!(timer->hw.flags & SNDRV_TIMER_HW_SLAVE) &&
  	    !timer->hw.resolution && timer->hw.c_resolution == NULL)
  	    	return -EINVAL;

  	mutex_lock(&register_mutex);

  	list_for_each_entry(timer1, &snd_timer_list, 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.. */

  		mutex_unlock(&register_mutex);

  		return -EBUSY;
  	}

  	list_add_tail(&timer->device_list, &timer1->device_list);

  	mutex_unlock(&register_mutex);

  	return 0;
  }

  static int snd_timer_dev_disconnect(struct snd_device *device)

  {

  	struct snd_timer *timer = device->device_data;

  	struct snd_timer_instance *ti;

  	mutex_lock(&register_mutex);

  	list_del_init(&timer->device_list);

  	/* wake up pending sleepers */
  	list_for_each_entry(ti, &timer->open_list_head, open_list) {

  		if (ti->disconnect)
  			ti->disconnect(ti);

  	}

  	mutex_unlock(&register_mutex);

  	return 0;

  }

  void snd_timer_notify(struct snd_timer *timer, int event, struct timespec *tstamp)

  {
  	unsigned long flags;
  	unsigned long resolution = 0;

  	struct snd_timer_instance *ti, *ts;

  	if (timer->card && timer->card->shutdown)
  		return;

  	if (! (timer->hw.flags & SNDRV_TIMER_HW_SLAVE))
  		return;

  	if (snd_BUG_ON(event < SNDRV_TIMER_EVENT_MSTART ||
  		       event > SNDRV_TIMER_EVENT_MRESUME))
  		return;

  	spin_lock_irqsave(&timer->lock, flags);

  	if (event == SNDRV_TIMER_EVENT_MSTART ||
  	    event == SNDRV_TIMER_EVENT_MCONTINUE ||
  	    event == SNDRV_TIMER_EVENT_MRESUME) {

  		if (timer->hw.c_resolution)
  			resolution = timer->hw.c_resolution(timer);
  		else
  			resolution = timer->hw.resolution;
  	}

  	list_for_each_entry(ti, &timer->active_list_head, active_list) {

  		if (ti->ccallback)
  			ti->ccallback(ti, event, tstamp, resolution);

  		list_for_each_entry(ts, &ti->slave_active_head, active_list)

  			if (ts->ccallback)
  				ts->ccallback(ts, event, tstamp, resolution);

  	}
  	spin_unlock_irqrestore(&timer->lock, flags);
  }

  EXPORT_SYMBOL(snd_timer_notify);

  
  /*
   * exported functions for global timers
   */

  int snd_timer_global_new(char *id, int device, struct snd_timer **rtimer)

  {

  	struct snd_timer_id 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);
  }

  EXPORT_SYMBOL(snd_timer_global_new);

  int snd_timer_global_free(struct snd_timer *timer)

  {
  	return snd_timer_free(timer);
  }

  EXPORT_SYMBOL(snd_timer_global_free);

  int snd_timer_global_register(struct snd_timer *timer)

  {

  	struct snd_device dev;

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

  EXPORT_SYMBOL(snd_timer_global_register);

  /*

   *  System timer
   */
  
  struct snd_timer_system_private {
  	struct timer_list tlist;

  	unsigned long last_expires;
  	unsigned long last_jiffies;
  	unsigned long correction;
  };

  static void snd_timer_s_function(unsigned long data)
  {

  	struct snd_timer *timer = (struct snd_timer *)data;

  	struct snd_timer_system_private *priv = timer->private_data;
  	unsigned long jiff = jiffies;
  	if (time_after(jiff, priv->last_expires))

  		priv->correction += (long)jiff - (long)priv->last_expires;

  	snd_timer_interrupt(timer, (long)jiff - (long)priv->last_jiffies);
  }

  static int snd_timer_s_start(struct snd_timer * timer)

  {
  	struct snd_timer_system_private *priv;
  	unsigned long njiff;
  
  	priv = (struct snd_timer_system_private *) timer->private_data;
  	njiff = (priv->last_jiffies = jiffies);
  	if (priv->correction > timer->sticks - 1) {
  		priv->correction -= timer->sticks - 1;
  		njiff++;
  	} else {
  		njiff += timer->sticks - priv->correction;

  		priv->correction = 0;

  	}

  	priv->last_expires = njiff;
  	mod_timer(&priv->tlist, njiff);

  	return 0;
  }

  static int snd_timer_s_stop(struct snd_timer * timer)

  {
  	struct snd_timer_system_private *priv;
  	unsigned long jiff;
  
  	priv = (struct snd_timer_system_private *) timer->private_data;
  	del_timer(&priv->tlist);
  	jiff = jiffies;
  	if (time_before(jiff, priv->last_expires))
  		timer->sticks = priv->last_expires - jiff;
  	else
  		timer->sticks = 1;

  	priv->correction = 0;

  	return 0;
  }

  static int snd_timer_s_close(struct snd_timer *timer)
  {
  	struct snd_timer_system_private *priv;
  
  	priv = (struct snd_timer_system_private *)timer->private_data;
  	del_timer_sync(&priv->tlist);
  	return 0;
  }

  static struct snd_timer_hardware snd_timer_system =

  {
  	.flags =	SNDRV_TIMER_HW_FIRST | SNDRV_TIMER_HW_TASKLET,
  	.resolution =	1000000000L / HZ,
  	.ticks =	10000000L,

  	.close =	snd_timer_s_close,

  	.start =	snd_timer_s_start,
  	.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;
  	}

  	setup_timer(&priv->tlist, snd_timer_s_function, (unsigned long) timer);

  	timer->private_data = priv;
  	timer->private_free = snd_timer_free_system;
  	return snd_timer_global_register(timer);
  }

  #ifdef CONFIG_SND_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) {

  		if (timer->card && timer->card->shutdown)
  			continue;

  		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, "
  ");

  		list_for_each_entry(ti, &timer->open_list_head, open_list)

  			snd_iprintf(buffer, "  Client %s : %s
  ",
  				    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_SND_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;

  	unsigned long flags;

  	if (event >= SNDRV_TIMER_EVENT_START &&
  	    event <= SNDRV_TIMER_EVENT_PAUSE)

  		tu->tstamp = *tstamp;
  	if ((tu->filter & (1 << event)) == 0 || !tu->tread)
  		return;

  	memset(&r1, 0, sizeof(r1));

  	r1.event = event;
  	r1.tstamp = *tstamp;
  	r1.val = resolution;

  	spin_lock_irqsave(&tu->qlock, flags);

  	snd_timer_user_append_to_tqueue(tu, &r1);

  	spin_unlock_irqrestore(&tu->qlock, flags);

  	kill_fasync(&tu->fasync, SIGIO, POLL_IN);
  	wake_up(&tu->qchange_sleep);
  }

  static void snd_timer_user_disconnect(struct snd_timer_instance *timeri)
  {
  	struct snd_timer_user *tu = timeri->callback_data;
  
  	tu->disconnected = true;
  	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(&r1, 0, sizeof(r1));

  	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) {
  		if (timer_tstamp_monotonic)

  			ktime_get_ts(&tstamp);

  		else
  			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 realloc_user_queue(struct snd_timer_user *tu, int size)
  {
  	struct snd_timer_read *queue = NULL;
  	struct snd_timer_tread *tqueue = NULL;
  
  	if (tu->tread) {
  		tqueue = kcalloc(size, sizeof(*tqueue), GFP_KERNEL);
  		if (!tqueue)
  			return -ENOMEM;
  	} else {
  		queue = kcalloc(size, sizeof(*queue), GFP_KERNEL);
  		if (!queue)
  			return -ENOMEM;
  	}
  
  	spin_lock_irq(&tu->qlock);
  	kfree(tu->queue);
  	kfree(tu->tqueue);
  	tu->queue_size = size;
  	tu->queue = queue;
  	tu->tqueue = tqueue;
  	tu->qhead = tu->qtail = tu->qused = 0;
  	spin_unlock_irq(&tu->qlock);
  
  	return 0;
  }

  static int snd_timer_user_open(struct inode *inode, struct file *file)
  {

  	struct snd_timer_user *tu;

  	int err;
  
  	err = nonseekable_open(inode, file);
  	if (err < 0)
  		return err;

  	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->ioctl_lock);

  	tu->ticks = 1;

  	if (realloc_user_queue(tu, 128) < 0) {

  		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;

  		mutex_lock(&tu->ioctl_lock);

  		if (tu->timeri)
  			snd_timer_close(tu->timeri);

  		mutex_unlock(&tu->ioctl_lock);

  		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.device < 0) {
  					id.device = 0;

  				} else {

  					if (id.subdevice < 0)
  						id.subdevice = 0;

  					else if (id.subdevice < INT_MAX)

  						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 = memdup_user(_ginfo, sizeof(*ginfo));
  	if (IS_ERR(ginfo))
  		return PTR_ERR(ginfo);

  	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 timer_set_gparams(struct snd_timer_gparams *gparams)

  {

  	struct snd_timer *t;

  	int err;

  	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_gparams(struct file *file,
  				  struct snd_timer_gparams __user *_gparams)
  {
  	struct snd_timer_gparams gparams;
  
  	if (copy_from_user(&gparams, _gparams, sizeof(gparams)))
  		return -EFAULT;
  	return timer_set_gparams(&gparams);
  }

  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;
  }

  static int snd_timer_user_tselect(struct file *file,

  				  struct snd_timer_select __user *_tselect)

  {

  	struct snd_timer_user *tu;
  	struct snd_timer_select tselect;

  	char str[32];

  	int err = 0;

  	tu = file->private_data;

  	if (tu->timeri) {

  		snd_timer_close(tu->timeri);

  		tu->timeri = NULL;
  	}
  	if (copy_from_user(&tselect, _tselect, sizeof(tselect))) {
  		err = -EFAULT;
  		goto __err;
  	}

  	sprintf(str, "application %i", current->pid);
  	if (tselect.id.dev_class != SNDRV_TIMER_CLASS_SLAVE)
  		tselect.id.dev_sclass = SNDRV_TIMER_SCLASS_APPLICATION;

  	err = snd_timer_open(&tu->timeri, str, &tselect.id, current->pid);
  	if (err < 0)

  		goto __err;

  	tu->timeri->flags |= SNDRV_TIMER_IFLG_FAST;
  	tu->timeri->callback = tu->tread

  			? snd_timer_user_tinterrupt : snd_timer_user_interrupt;

  	tu->timeri->ccallback = snd_timer_user_ccallback;
  	tu->timeri->callback_data = (void *)tu;
  	tu->timeri->disconnect = snd_timer_user_disconnect;

  
        __err:

  	return err;

  }

  static int snd_timer_user_info(struct file *file,

  			       struct snd_timer_info __user *_info)

  {

  	struct snd_timer_user *tu;
  	struct snd_timer_info *info;
  	struct snd_timer *t;

  	int err = 0;
  
  	tu = file->private_data;

  	if (!tu->timeri)
  		return -EBADFD;

  	t = tu->timeri->timer;

  	if (!t)
  		return -EBADFD;

  	info = kzalloc(sizeof(*info), GFP_KERNEL);

  	if (! info)
  		return -ENOMEM;
  	info->card = t->card ? t->card->number : -1;
  	if (t->hw.flags & SNDRV_TIMER_HW_SLAVE)
  		info->flags |= SNDRV_TIMER_FLG_SLAVE;
  	strlcpy(info->id, t->id, sizeof(info->id));
  	strlcpy(info->name, t->name, sizeof(info->name));
  	info->resolution = t->hw.resolution;
  	if (copy_to_user(_info, info, sizeof(*_info)))
  		err = -EFAULT;
  	kfree(info);
  	return err;
  }

  static int snd_timer_user_params(struct file *file,

  				 struct snd_timer_params __user *_params)

  {

  	struct snd_timer_user *tu;
  	struct snd_timer_params params;
  	struct snd_timer *t;

  	int err;

  	tu = file->private_data;

  	if (!tu->timeri)
  		return -EBADFD;

  	t = tu->timeri->timer;

  	if (!t)
  		return -EBADFD;

  	if (copy_from_user(&params, _params, sizeof(params)))
  		return -EFAULT;

  	if (!(t->hw.flags & SNDRV_TIMER_HW_SLAVE)) {
  		u64 resolution;
  
  		if (params.ticks < 1) {
  			err = -EINVAL;
  			goto _end;
  		}
  
  		/* Don't allow resolution less than 1ms */
  		resolution = snd_timer_resolution(tu->timeri);
  		resolution *= params.ticks;
  		if (resolution < 1000000) {
  			err = -EINVAL;
  			goto _end;
  		}

  	}

  	if (params.queue_size > 0 &&
  	    (params.queue_size < 32 || params.queue_size > 1024)) {

  		err = -EINVAL;
  		goto _end;
  	}
  	if (params.filter & ~((1<<SNDRV_TIMER_EVENT_RESOLUTION)|
  			      (1<<SNDRV_TIMER_EVENT_TICK)|
  			      (1<<SNDRV_TIMER_EVENT_START)|
  			      (1<<SNDRV_TIMER_EVENT_STOP)|
  			      (1<<SNDRV_TIMER_EVENT_CONTINUE)|
  			      (1<<SNDRV_TIMER_EVENT_PAUSE)|

  			      (1<<SNDRV_TIMER_EVENT_SUSPEND)|
  			      (1<<SNDRV_TIMER_EVENT_RESUME)|

  			      (1<<SNDRV_TIMER_EVENT_MSTART)|
  			      (1<<SNDRV_TIMER_EVENT_MSTOP)|
  			      (1<<SNDRV_TIMER_EVENT_MCONTINUE)|

  			      (1<<SNDRV_TIMER_EVENT_MPAUSE)|
  			      (1<<SNDRV_TIMER_EVENT_MSUSPEND)|

  			      (1<<SNDRV_TIMER_EVENT_MRESUME))) {

  		err = -EINVAL;
  		goto _end;
  	}
  	snd_timer_stop(tu->timeri);
  	spin_lock_irq(&t->lock);
  	tu->timeri->flags &= ~(SNDRV_TIMER_IFLG_AUTO|
  			       SNDRV_TIMER_IFLG_EXCLUSIVE|
  			       SNDRV_TIMER_IFLG_EARLY_EVENT);
  	if (params.flags & SNDRV_TIMER_PSFLG_AUTO)
  		tu->timeri->flags |= SNDRV_TIMER_IFLG_AUTO;
  	if (params.flags & SNDRV_TIMER_PSFLG_EXCLUSIVE)
  		tu->timeri->flags |= SNDRV_TIMER_IFLG_EXCLUSIVE;
  	if (params.flags & SNDRV_TIMER_PSFLG_EARLY_EVENT)
  		tu->timeri->flags |= SNDRV_TIMER_IFLG_EARLY_EVENT;
  	spin_unlock_irq(&t->lock);

  	if (params.queue_size > 0 &&
  	    (unsigned int)tu->queue_size != params.queue_size) {

  		err = realloc_user_queue(tu, params.queue_size);
  		if (err < 0)
  			goto _end;

  	}

  	spin_lock_irq(&tu->qlock);

  	tu->qhead = tu->qtail = tu->qused = 0;
  	if (tu->timeri->flags & SNDRV_TIMER_IFLG_EARLY_EVENT) {
  		if (tu->tread) {

  			struct snd_timer_tread tread;

  			memset(&tread, 0, sizeof(tread));

  			tread.event = SNDRV_TIMER_EVENT_EARLY;
  			tread.tstamp.tv_sec = 0;
  			tread.tstamp.tv_nsec = 0;
  			tread.val = 0;
  			snd_timer_user_append_to_tqueue(tu, &tread);
  		} else {

  			struct snd_timer_read *r = &tu->queue[0];