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Sourcecode: alsa-driver version File versions

timer.c

/*
 *  Timers abstract layer
 *  Copyright (c) by Jaroslav Kysela <perex@suse.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 <sound/driver.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/smp_lock.h>
#include <linux/slab.h>
#include <linux/time.h>
#include <linux/moduleparam.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>
#ifdef CONFIG_KERNELD
#include <linux/kerneld.h>
#endif

#if !defined(CONFIG_SND_RTCTIMER) && !defined(CONFIG_SND_RTCTIMER_MODULE)
#define DEFAULT_TIMER_LIMIT 1
#else
#define DEFAULT_TIMER_LIMIT 2
#endif

static int timer_limit = DEFAULT_TIMER_LIMIT;
MODULE_AUTHOR("Jaroslav Kysela <perex@suse.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.");

typedef struct {
      snd_timer_instance_t *timeri;
      int tread;              /* enhanced read with timestamps and events */
      unsigned long ticks;
      unsigned long overrun;
      int qhead;
      int qtail;
      int qused;
      int queue_size;
      snd_timer_read_t *queue;
      snd_timer_tread_t *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;
} snd_timer_user_t;

/* 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 spinlock_t slave_active_lock = SPIN_LOCK_UNLOCKED;

static DECLARE_MUTEX(register_mutex);

static int snd_timer_free(snd_timer_t *timer);
static int snd_timer_dev_free(snd_device_t *device);
static int snd_timer_dev_register(snd_device_t *device);
static int snd_timer_dev_unregister(snd_device_t *device);

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

/*
 * create a timer instance with the given owner string.
 * when timer is not NULL, increments the module counter
 */
static snd_timer_instance_t *snd_timer_instance_new(char *owner, snd_timer_t *timer)
{
      snd_timer_instance_t *timeri;
      timeri = kcalloc(1, sizeof(*timeri), GFP_KERNEL);
      if (timeri == NULL)
            return NULL;
      timeri->owner = snd_kmalloc_strdup(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 && timer->card && !try_module_get(timer->card->module)) {
            kfree(timeri->owner);
            kfree(timeri);
            return NULL;
      }

      return timeri;
}

/*
 * find a timer instance from the given timer id
 */
static snd_timer_t *snd_timer_find(snd_timer_id_t *tid)
{
      snd_timer_t *timer = NULL;
      struct list_head *p;

      list_for_each(p, &snd_timer_list) {
            timer = (snd_timer_t *)list_entry(p, snd_timer_t, 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_KMOD

static void snd_timer_request(snd_timer_id_t *tid)
{
      if (! current->fs->root)
            return;
      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 void snd_timer_check_slave(snd_timer_instance_t *slave)
{
      snd_timer_t *timer;
      snd_timer_instance_t *master;
      struct list_head *p, *q;

      /* FIXME: it's really dumb to look up all entries.. */
      list_for_each(p, &snd_timer_list) {
            timer = (snd_timer_t *)list_entry(p, snd_timer_t, device_list);
            list_for_each(q, &timer->open_list_head) {
                  master = (snd_timer_instance_t *)list_entry(q, snd_timer_instance_t, open_list);
                  if (slave->slave_class == master->slave_class &&
                      slave->slave_id == master->slave_id) {
                        list_del(&slave->open_list);
                        list_add_tail(&slave->open_list, &master->slave_list_head);
                        spin_lock_irq(&slave_active_lock);
                        slave->master = master;
                        slave->timer = master->timer;
                        spin_unlock_irq(&slave_active_lock);
                        return;
                  }
            }
      }
}

/*
 * 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 void snd_timer_check_master(snd_timer_instance_t *master)
{
      snd_timer_instance_t *slave;
      struct list_head *p, *n;

      /* check all pending slaves */
      list_for_each_safe(p, n, &snd_timer_slave_list) {
            slave = (snd_timer_instance_t *)list_entry(p, snd_timer_instance_t, open_list);
            if (slave->slave_class == master->slave_class &&
                slave->slave_id == master->slave_id) {
                  list_del(p);
                  list_add_tail(p, &master->slave_list_head);
                  spin_lock_irq(&slave_active_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_irq(&slave_active_lock);
            }
      }
}

/*
 * open a timer instance
 * when opening a master, the slave id must be here given.
 */
int snd_timer_open(snd_timer_instance_t **ti,
               char *owner, snd_timer_id_t *tid,
               unsigned int slave_id)
{
      snd_timer_t *timer;
      snd_timer_instance_t *timeri = NULL;
      
      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) {
                  snd_printd("invalid slave class %i\n", tid->dev_sclass);
                  return -EINVAL;
            }
            down(&register_mutex);
            timeri = snd_timer_instance_new(owner, NULL);
            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);
            snd_timer_check_slave(timeri);
            up(&register_mutex);
            *ti = timeri;
            return 0;
      }

      /* open a master instance */
      down(&register_mutex);
      timer = snd_timer_find(tid);
#ifdef CONFIG_KMOD
      if (timer == NULL) {
            up(&register_mutex);
            snd_timer_request(tid);
            down(&register_mutex);
            timer = snd_timer_find(tid);
      }
#endif
      if (timer) {
            if (!list_empty(&timer->open_list_head)) {
                  timeri = (snd_timer_instance_t *)list_entry(timer->open_list_head.next, snd_timer_instance_t, open_list);
                  if (timeri->flags & SNDRV_TIMER_IFLG_EXCLUSIVE) {
                        up(&register_mutex);
                        return -EBUSY;
                  }
            }
            timeri = snd_timer_instance_new(owner, timer);
            if (timeri) {
                  timeri->slave_class = tid->dev_sclass;
                  timeri->slave_id = slave_id;
                  if (list_empty(&timer->open_list_head) && timer->hw.open)
                        timer->hw.open(timer);
                  list_add_tail(&timeri->open_list, &timer->open_list_head);
                  snd_timer_check_master(timeri);
            }
      } else {
            up(&register_mutex);
            return -ENODEV;
      }
      up(&register_mutex);
      *ti = timeri;
      return 0;
}

static int _snd_timer_stop(snd_timer_instance_t * timeri, int keep_flag, enum sndrv_timer_event event);

/*
 * close a timer instance
 */
int snd_timer_close(snd_timer_instance_t * timeri)
{
      snd_timer_t *timer = NULL;
      struct list_head *p, *n;
      snd_timer_instance_t *slave;

      snd_assert(timeri != NULL, return -ENXIO);

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

      if (timeri->flags & SNDRV_TIMER_IFLG_SLAVE) {
            /* wait, until the active callback is finished */
            spin_lock_irq(&slave_active_lock);
            while (timeri->flags & SNDRV_TIMER_IFLG_CALLBACK) {
                  spin_unlock_irq(&slave_active_lock);
                  udelay(10);
                  spin_lock_irq(&slave_active_lock);
            }
            spin_unlock_irq(&slave_active_lock);
            down(&register_mutex);
            list_del(&timeri->open_list);
            up(&register_mutex);
      } else {
            timer = timeri->timer;
            /* 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);
            down(&register_mutex);
            list_del(&timeri->open_list);
            if (timer && list_empty(&timer->open_list_head) && timer->hw.close)
                  timer->hw.close(timer);
            /* remove slave links */
            list_for_each_safe(p, n, &timeri->slave_list_head) {
                  slave = (snd_timer_instance_t *)list_entry(p, snd_timer_instance_t, open_list);
                  spin_lock_irq(&slave_active_lock);
                  _snd_timer_stop(slave, 1, SNDRV_TIMER_EVENT_RESOLUTION);
                  list_del(p);
                  list_add_tail(p, &snd_timer_slave_list);
                  slave->master = NULL;
                  slave->timer = NULL;
                  spin_unlock_irq(&slave_active_lock);
            }
            up(&register_mutex);
      }
      if (timeri->private_free)
            timeri->private_free(timeri);
      kfree(timeri->owner);
      kfree(timeri);
      if (timer && timer->card)
            module_put(timer->card->module);
      return 0;
}

unsigned long snd_timer_resolution(snd_timer_instance_t * timeri)
{
      snd_timer_t * timer;

      if (timeri == NULL)
            return 0;
      if ((timer = timeri->timer) != NULL) {
            if (timer->hw.c_resolution)
                  return timer->hw.c_resolution(timer);
            return timer->hw.resolution;
      }
      return 0;
}

static void snd_timer_notify1(snd_timer_instance_t *ti, enum sndrv_timer_event event)
{
      snd_timer_t *timer;
      unsigned long flags;
      unsigned long resolution = 0;
      snd_timer_instance_t *ts;
      struct list_head *n;
      struct timespec tstamp;

      snd_timestamp_now(&tstamp, 1);
      snd_assert(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, SNDRV_TIMER_EVENT_START, &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;
      spin_lock_irqsave(&timer->lock, flags);
      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(ti, event + 100, &tstamp, resolution);
      }
      spin_unlock_irqrestore(&timer->lock, flags);
}

static int snd_timer_start1(snd_timer_t *timer, snd_timer_instance_t *timeri, unsigned long sticks)
{
      list_del(&timeri->active_list);
      list_add_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;
            return 1;   /* delayed start */
      } else {
            timer->sticks = sticks;
            timer->hw.start(timer);
            __start_now:
            timer->running++;
            timeri->flags |= SNDRV_TIMER_IFLG_RUNNING;
            return 0;
      }
}

static int snd_timer_start_slave(snd_timer_instance_t *timeri)
{
      unsigned long flags;

      spin_lock_irqsave(&slave_active_lock, flags);
      timeri->flags |= SNDRV_TIMER_IFLG_RUNNING;
      if (timeri->master)
            list_add_tail(&timeri->active_list, &timeri->master->slave_active_head);
      spin_unlock_irqrestore(&slave_active_lock, flags);
      return 1; /* delayed start */
}

/*
 *  start the timer instance
 */ 
int snd_timer_start(snd_timer_instance_t * timeri, unsigned int ticks)
{
      snd_timer_t *timer;
      int result = -EINVAL;
      unsigned long flags;

      if (timeri == NULL || ticks < 1)
            return -EINVAL;
      if (timeri->flags & SNDRV_TIMER_IFLG_SLAVE) {
            result = snd_timer_start_slave(timeri);
            snd_timer_notify1(timeri, SNDRV_TIMER_EVENT_START);
            return result;
      }
      timer = timeri->timer;
      if (timer == NULL)
            return -EINVAL;
      spin_lock_irqsave(&timer->lock, flags);
      timeri->ticks = timeri->cticks = ticks;
      timeri->pticks = 0;
      result = snd_timer_start1(timer, timeri, ticks);
      spin_unlock_irqrestore(&timer->lock, flags);
      snd_timer_notify1(timeri, SNDRV_TIMER_EVENT_START);
      return result;
}

static int _snd_timer_stop(snd_timer_instance_t * timeri, int keep_flag, enum sndrv_timer_event event)
{
      snd_timer_t *timer;
      unsigned long flags;

      snd_assert(timeri != NULL, return -ENXIO);

      if (timeri->flags & SNDRV_TIMER_IFLG_SLAVE) {
            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)
{
      return 1000000000L / HZ;
}

static void snd_timer_s_function(unsigned long data)
{
      snd_timer_t *timer = (snd_timer_t *)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(snd_timer_t * 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 -= timer->sticks;
      }
      priv->last_expires = priv->tlist.expires = njiff;
      add_timer(&priv->tlist);
      return 0;
}

static int snd_timer_s_stop(snd_timer_t * 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;
      return 0;
}

static struct _snd_timer_hardware snd_timer_system =
{
      .flags =    SNDRV_TIMER_HW_FIRST | SNDRV_TIMER_HW_TASKLET,
      .resolution =     1000000000L / HZ,
      .ticks =    10000000L,
      .start =    snd_timer_s_start,
      .stop =           snd_timer_s_stop
};

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

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

      if ((err = snd_timer_global_new("system", SNDRV_TIMER_GLOBAL_SYSTEM, &timer)) < 0)
            return err;
      strcpy(timer->name, "system timer");
      timer->hw = snd_timer_system;
      priv = kcalloc(1, 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);
}

/*
 *  Info interface
 */

static void snd_timer_proc_read(snd_info_entry_t *entry,
                        snd_info_buffer_t * buffer)
{
      unsigned long flags;
      snd_timer_t *timer;
      snd_timer_instance_t *ti;
      struct list_head *p, *q;

      down(&register_mutex);
      list_for_each(p, &snd_timer_list) {
            timer = (snd_timer_t *)list_entry(p, snd_timer_t, 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");
            spin_lock_irqsave(&timer->lock, flags);
            list_for_each(q, &timer->open_list_head) {
                  ti = (snd_timer_instance_t *)list_entry(q, snd_timer_instance_t, open_list);
                  snd_iprintf(buffer, "  Client %s : %s : lost interrupts %li\n",
                              ti->owner ? ti->owner : "unknown",
                              ti->flags & (SNDRV_TIMER_IFLG_START|SNDRV_TIMER_IFLG_RUNNING) ? "running" : "stopped",
                              ti->lost);
            }
            spin_unlock_irqrestore(&timer->lock, flags);
      }
      up(&register_mutex);
}

/*
 *  USER SPACE interface
 */

static void snd_timer_user_interrupt(snd_timer_instance_t *timeri,
                             unsigned long resolution,
                             unsigned long ticks)
{
      snd_timer_user_t *tu = timeri->callback_data;
      snd_timer_read_t *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(snd_timer_user_t *tu, snd_timer_tread_t *tread)
{
      if (tu->qused >= tu->queue_size) {
            tu->overrun++;
      } else {
            memcpy(&tu->queue[tu->qtail++], tread, sizeof(*tread));
            tu->qused++;
      }
}

static void snd_timer_user_ccallback(snd_timer_instance_t *timeri,
                             enum sndrv_timer_event event,
                             struct timespec *tstamp,
                             unsigned long resolution)
{
      snd_timer_user_t *tu = timeri->callback_data;
      snd_timer_tread_t 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);
}

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

      snd_timestamp_zero(&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)
            snd_timestamp_now(&tstamp, 1);
      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)
{
      snd_timer_user_t *tu;
      
      tu = kcalloc(1, sizeof(*tu), GFP_KERNEL);
      if (tu == NULL)
            return -ENOMEM;
      spin_lock_init(&tu->qlock);
      init_waitqueue_head(&tu->qchange_sleep);
      tu->ticks = 1;
      tu->queue_size = 128;
      tu->queue = (snd_timer_read_t *)kmalloc(tu->queue_size * sizeof(snd_timer_read_t), 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)
{
      snd_timer_user_t *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(snd_timer_id_t *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(snd_timer_id_t *id, snd_timer_t *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(snd_timer_id_t __user *_tid)
{
      snd_timer_id_t id;
      snd_timer_t *timer;
      struct list_head *p;
      
      if (copy_from_user(&id, _tid, sizeof(id)))
            return -EFAULT;
      down(&register_mutex);
      if (id.dev_class < 0) {       /* first item */
            if (list_empty(&snd_timer_list))
                  snd_timer_user_zero_id(&id);
            else {
                  timer = (snd_timer_t *)list_entry(snd_timer_list.next, snd_timer_t, 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 = (snd_timer_t *)list_entry(p, snd_timer_t, 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 {
                                    id.subdevice = id.subdevice < 0 ? 0 : id.subdevice + 1;
                              }
                        }
                  }
                  list_for_each(p, &snd_timer_list) {
                        timer = (snd_timer_t *)list_entry(p, snd_timer_t, 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);
            }
      }
      up(&register_mutex);
      if (copy_to_user(_tid, &id, sizeof(*_tid)))
            return -EFAULT;
      return 0;
} 

static int snd_timer_user_ginfo(struct file *file, snd_timer_ginfo_t __user *_ginfo)
{
      snd_timer_ginfo_t ginfo;
      snd_timer_id_t tid;
      snd_timer_t *t;
      struct list_head *p;
      int err = 0;

      if (copy_from_user(&ginfo, _ginfo, sizeof(ginfo)))
            return -EFAULT;
      tid = ginfo.tid;
      memset(&ginfo, 0, sizeof(ginfo));
      ginfo.tid = tid;
      down(&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;
      }
      up(&register_mutex);
      if (err >= 0 && copy_to_user(_ginfo, &ginfo, sizeof(ginfo)))
            err = -EFAULT;
      return err;
}

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

      if (copy_from_user(&gparams, _gparams, sizeof(gparams)))
            return -EFAULT;
      down(&register_mutex);
      t = snd_timer_find(&gparams.tid);
      if (t != NULL) {
            if (list_empty(&t->open_list_head)) {
                  if (t->hw.set_period)
                        err = t->hw.set_period(t, gparams.period_num, gparams.period_den);
                  else
                        err = -ENOSYS;
            } else {
                  err = -EBUSY;
            }
      } else {
            err = -ENODEV;
      }
      up(&register_mutex);
      return err;
}

static int snd_timer_user_gstatus(struct file *file, snd_timer_gstatus_t __user *_gstatus)
{
      snd_timer_gstatus_t gstatus;
      snd_timer_id_t tid;
      snd_timer_t *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;
      down(&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;
      }
      up(&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, snd_timer_select_t __user *_tselect)
{
      snd_timer_user_t *tu;
      snd_timer_select_t tselect;
      char str[32];
      int err;
      
      tu = file->private_data;
      if (tu->timeri)
            snd_timer_close(tu->timeri);
      if (copy_from_user(&tselect, _tselect, sizeof(tselect)))
            return -EFAULT;
      sprintf(str, "application %i", current->pid);
      if (tselect.id.dev_class != SNDRV_TIMER_CLASS_SLAVE)
            tselect.id.dev_sclass = SNDRV_TIMER_SCLASS_APPLICATION;
      if ((err = snd_timer_open(&tu->timeri, str, &tselect.id, current->pid)) < 0)
            return err;

      if (tu->queue) {
            kfree(tu->queue);
            tu->queue = NULL;
      }
      if (tu->tqueue) {
            kfree(tu->tqueue);
            tu->tqueue = NULL;
      }
      if (tu->tread) {
            tu->tqueue = (snd_timer_tread_t *)kmalloc(tu->queue_size * sizeof(snd_timer_tread_t), GFP_KERNEL);
            if (tu->tqueue == NULL) {
                  snd_timer_close(tu->timeri);
                  return -ENOMEM;
            }
      } else {
            tu->queue = (snd_timer_read_t *)kmalloc(tu->queue_size * sizeof(snd_timer_read_t), GFP_KERNEL);
            if (tu->queue == NULL) {
                  snd_timer_close(tu->timeri);
                  return -ENOMEM;
            }
      }
      
      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;
      return 0;
}

static int snd_timer_user_info(struct file *file, snd_timer_info_t __user *_info)
{
      snd_timer_user_t *tu;
      snd_timer_info_t info;
      snd_timer_t *t;

      tu = file->private_data;
      snd_assert(tu->timeri != NULL, return -ENXIO);
      t = tu->timeri->timer;
      snd_assert(t != NULL, return -ENXIO);
      memset(&info, 0, sizeof(info));
      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)))
            return -EFAULT;
      return 0;
}

static int snd_timer_user_params(struct file *file, snd_timer_params_t __user *_params)
{
      snd_timer_user_t *tu;
      snd_timer_params_t params;
      snd_timer_t *t;
      snd_timer_read_t *tr;
      snd_timer_tread_t *ttr;
      int err;
      
      tu = file->private_data;
      snd_assert(tu->timeri != NULL, return -ENXIO);
      t = tu->timeri->timer;
      snd_assert(t != NULL, return -ENXIO);
      if (copy_from_user(&params, _params, sizeof(params)))
            return -EFAULT;
      if (!(t->hw.flags & SNDRV_TIMER_HW_SLAVE) && params.ticks < 1) {
            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_MSTART)|
                        (1<<SNDRV_TIMER_EVENT_MSTOP)|
                        (1<<SNDRV_TIMER_EVENT_MCONTINUE)|
                        (1<<SNDRV_TIMER_EVENT_MPAUSE))) {
            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) {
            if (tu->tread) {
                  ttr = (snd_timer_tread_t *)kmalloc(params.queue_size * sizeof(snd_timer_tread_t), GFP_KERNEL);
                  if (ttr) {
                        kfree(tu->tqueue);
                        tu->queue_size = params.queue_size;
                        tu->tqueue = ttr;
                  }
            } else {
                  tr = (snd_timer_read_t *)kmalloc(params.queue_size * sizeof(snd_timer_read_t), GFP_KERNEL);
                  if (tr) {
                        kfree(tu->queue);
                        tu->queue_size = params.queue_size;
                        tu->queue = tr;
                  }
            }
      }
      tu->qhead = tu->qtail = tu->qused = 0;
      if (tu->timeri->flags & SNDRV_TIMER_IFLG_EARLY_EVENT) {
            if (tu->tread) {
                  snd_timer_tread_t 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 {
                  snd_timer_read_t *r = &tu->queue[0];
                  r->resolution = 0;
                  r->ticks = 0;
                  tu->qused++;
                  tu->qtail++;
            }
            
      }
      tu->filter = params.filter;
      tu->ticks = params.ticks;
      err = 0;
 _end:
      if (copy_to_user(_params, &params, sizeof(params)))
            return -EFAULT;
      return err;
}

static int snd_timer_user_status(struct file *file, snd_timer_status_t __user *_status)
{
      snd_timer_user_t *tu;
      snd_timer_status_t status;
      
      tu = file->private_data;
      snd_assert(tu->timeri != NULL, return -ENXIO);
      memset(&status, 0, sizeof(status));
      status.tstamp = tu->tstamp;
      status.resolution = snd_timer_resolution(tu->timeri);
      status.lost = tu->timeri->lost;
      status.overrun = tu->overrun;
      spin_lock_irq(&tu->qlock);
      status.queue = tu->qused;
      spin_unlock_irq(&tu->qlock);
      if (copy_to_user(_status, &status, sizeof(status)))
            return -EFAULT;
      return 0;
}

static int snd_timer_user_start(struct file *file)
{
      int err;
      snd_timer_user_t *tu;
            
      tu = file->private_data;
      snd_assert(tu->timeri != NULL, return -ENXIO);
      snd_timer_stop(tu->timeri);
      tu->timeri->lost = 0;
      tu->last_resolution = 0;
      return (err = snd_timer_start(tu->timeri, tu->ticks)) < 0 ? err : 0;
}

static int snd_timer_user_stop(struct file *file)
{
      int err;
      snd_timer_user_t *tu;
            
      tu = file->private_data;
      snd_assert(tu->timeri != NULL, return -ENXIO);
      return (err = snd_timer_stop(tu->timeri)) < 0 ? err : 0;
}

static int snd_timer_user_continue(struct file *file)
{
      int err;
      snd_timer_user_t *tu;
            
      tu = file->private_data;
      snd_assert(tu->timeri != NULL, return -ENXIO);
      tu->timeri->lost = 0;
      return (err = snd_timer_continue(tu->timeri)) < 0 ? err : 0;
}

static inline int _snd_timer_user_ioctl(struct inode *inode, struct file *file,
                              unsigned int cmd, unsigned long arg)
{
      snd_timer_user_t *tu;
      void __user *argp = (void __user *)arg;
      int __user *p = argp;
      
      tu = file->private_data;
      switch (cmd) {
      case SNDRV_TIMER_IOCTL_PVERSION:
            return put_user(SNDRV_TIMER_VERSION, p) ? -EFAULT : 0;
      case SNDRV_TIMER_IOCTL_NEXT_DEVICE:
            return snd_timer_user_next_device(argp);
      case SNDRV_TIMER_IOCTL_TREAD:
      {
            int xarg;
            
            if (tu->timeri)         /* too late */
                  return -EBUSY;
            if (get_user(xarg, p))
                  return -EFAULT;
            tu->tread = xarg ? 1 : 0;
            return 0;
      }
      case SNDRV_TIMER_IOCTL_GINFO:
            return snd_timer_user_ginfo(file, argp);
      case SNDRV_TIMER_IOCTL_GPARAMS:
            return snd_timer_user_gparams(file, argp);
      case SNDRV_TIMER_IOCTL_GSTATUS:
            return snd_timer_user_gstatus(file, argp);
      case SNDRV_TIMER_IOCTL_SELECT:
            return snd_timer_user_tselect(file, argp);
      case SNDRV_TIMER_IOCTL_INFO:
            return snd_timer_user_info(file, argp);
      case SNDRV_TIMER_IOCTL_PARAMS:
            return snd_timer_user_params(file, argp);
      case SNDRV_TIMER_IOCTL_STATUS:
            return snd_timer_user_status(file, argp);
      case SNDRV_TIMER_IOCTL_START:
            return snd_timer_user_start(file);
      case SNDRV_TIMER_IOCTL_STOP:
            return snd_timer_user_stop(file);
      case SNDRV_TIMER_IOCTL_CONTINUE:
            return snd_timer_user_continue(file);
      }
      return -ENOTTY;
}

/* FIXME: need to unlock BKL to allow preemption */
static int snd_timer_user_ioctl(struct inode *inode, struct file * file,
                        unsigned int cmd, unsigned long arg)
{
      int err;
      unlock_kernel();
      err = _snd_timer_user_ioctl(inode, file, cmd, arg);
      lock_kernel();
      return err;
}

static int snd_timer_user_fasync(int fd, struct file * file, int on)
{
      snd_timer_user_t *tu;
      int err;
      
      tu = file->private_data;
      err = fasync_helper(fd, file, on, &tu->fasync);
        if (err < 0)
            return err;
      return 0;
}

static ssize_t snd_timer_user_read(struct file *file, char __user *buffer, size_t count, loff_t *offset)
{
      snd_timer_user_t *tu;
      long result = 0, unit;
      int err = 0;
      
      tu = file->private_data;
      unit = tu->tread ? sizeof(snd_timer_tread_t) : sizeof(snd_timer_read_t);
      spin_lock_irq(&tu->qlock);
      while ((long)count - result >= unit) {
            while (!tu->qused) {
                  wait_queue_t wait;

                  if ((file->f_flags & O_NONBLOCK) != 0 || result > 0) {
                        err = -EAGAIN;
                        break;
                  }

                  set_current_state(TASK_INTERRUPTIBLE);
                  init_waitqueue_entry(&wait, current);
                  add_wait_queue(&tu->qchange_sleep, &wait);

                  spin_unlock_irq(&tu->qlock);
                  schedule();
                  spin_lock_irq(&tu->qlock);

                  remove_wait_queue(&tu->qchange_sleep, &wait);

                  if (signal_pending(current)) {
                        err = -ERESTARTSYS;
                        break;
                  }
            }

            spin_unlock_irq(&tu->qlock);
            if (err < 0)
                  goto _error;

            if (tu->tread) {
                  if (copy_to_user(buffer, &tu->tqueue[tu->qhead++], sizeof(snd_timer_tread_t))) {
                        err = -EFAULT;
                        goto _error;
                  }
            } else {
                  if (copy_to_user(buffer, &tu->queue[tu->qhead++], sizeof(snd_timer_read_t))) {
                        err = -EFAULT;
                        goto _error;
                  }
            }

            tu->qhead %= tu->queue_size;

            result += unit;
            buffer += unit;

            spin_lock_irq(&tu->qlock);
            tu->qused--;
      }
      spin_unlock_irq(&tu->qlock);
 _error:
      return result > 0 ? result : err;
}

static unsigned int snd_timer_user_poll(struct file *file, poll_table * wait)
{
        unsigned int mask;
        snd_timer_user_t *tu;

        tu = file->private_data;

        poll_wait(file, &tu->qchange_sleep, wait);
      
      mask = 0;
      if (tu->qused)
            mask |= POLLIN | POLLRDNORM;

      return mask;
}

static struct file_operations snd_timer_f_ops =
{
      .owner =    THIS_MODULE,
      .read =           snd_timer_user_read,
      .open =           snd_timer_user_open,
      .release =  snd_timer_user_release,
      .poll =           snd_timer_user_poll,
      .ioctl =    snd_timer_user_ioctl,
      .fasync =   snd_timer_user_fasync,
};

static snd_minor_t snd_timer_reg =
{
      .comment =  "timer",
      .f_ops =    &snd_timer_f_ops,
};

/*
 *  ENTRY functions
 */

static snd_info_entry_t *snd_timer_proc_entry = NULL;

static int __init alsa_timer_init(void)
{
      int err;
      snd_info_entry_t *entry;

#ifdef SNDRV_OSS_INFO_DEV_TIMERS
      snd_oss_info_register(SNDRV_OSS_INFO_DEV_TIMERS, SNDRV_CARDS - 1, "system timer");
#endif
      if ((entry = snd_info_create_module_entry(THIS_MODULE, "timers", NULL)) != NULL) {
            entry->c.text.read_size = SNDRV_TIMER_DEVICES * 128;
            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;
      if ((err = snd_timer_register_system()) < 0)
            snd_printk(KERN_ERR "unable to register system timer (%i)\n", err);
      if ((err = snd_register_device(SNDRV_DEVICE_TYPE_TIMER,
                              NULL, 0, &snd_timer_reg, "timer"))<0)
            snd_printk(KERN_ERR "unable to register timer device (%i)\n", err);
      return 0;
}

static void __exit alsa_timer_exit(void)
{
      struct list_head *p, *n;

      snd_unregister_device(SNDRV_DEVICE_TYPE_TIMER, NULL, 0);
      /* unregister the system timer */
      list_for_each_safe(p, n, &snd_timer_list) {
            snd_timer_t *timer = (snd_timer_t *)list_entry(p, snd_timer_t, device_list);
            snd_timer_unregister(timer);
      }
      if (snd_timer_proc_entry) {
            snd_info_unregister(snd_timer_proc_entry);
            snd_timer_proc_entry = NULL;
      }
#ifdef SNDRV_OSS_INFO_DEV_TIMERS
      snd_oss_info_unregister(SNDRV_OSS_INFO_DEV_TIMERS, SNDRV_CARDS - 1);
#endif
}

module_init(alsa_timer_init)
module_exit(alsa_timer_exit)

EXPORT_SYMBOL(snd_timer_open);
EXPORT_SYMBOL(snd_timer_close);
EXPORT_SYMBOL(snd_timer_resolution);
EXPORT_SYMBOL(snd_timer_start);
EXPORT_SYMBOL(snd_timer_stop);
EXPORT_SYMBOL(snd_timer_continue);
EXPORT_SYMBOL(snd_timer_pause);
EXPORT_SYMBOL(snd_timer_new);
EXPORT_SYMBOL(snd_timer_notify);
EXPORT_SYMBOL(snd_timer_global_new);
EXPORT_SYMBOL(snd_timer_global_free);
EXPORT_SYMBOL(snd_timer_global_register);
EXPORT_SYMBOL(snd_timer_global_unregister);
EXPORT_SYMBOL(snd_timer_interrupt);
EXPORT_SYMBOL(snd_timer_system_resolution);

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