/*
   *  Digital Audio (PCM) 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/time.h>

  #include <linux/gcd.h>

  #include <sound/core.h>
  #include <sound/pcm.h>
  #include <sound/timer.h>
  
  /*
   *  Timer functions
   */

  void snd_pcm_timer_resolution_change(struct snd_pcm_substream *substream)

  {
  	unsigned long rate, mult, fsize, l, post;

  	struct snd_pcm_runtime *runtime = substream->runtime;

  	
          mult = 1000000000;
  	rate = runtime->rate;

  	if (snd_BUG_ON(!rate))
  		return;

  	l = gcd(mult, rate);
  	mult /= l;
  	rate /= l;
  	fsize = runtime->period_size;

  	if (snd_BUG_ON(!fsize))
  		return;

  	l = gcd(rate, fsize);
  	rate /= l;
  	fsize /= l;
  	post = 1;
  	while ((mult * fsize) / fsize != mult) {
  		mult /= 2;
  		post *= 2;
  	}
  	if (rate == 0) {
  		snd_printk(KERN_ERR "pcm timer resolution out of range (rate = %u, period_size = %lu)
  ", runtime->rate, runtime->period_size);
  		runtime->timer_resolution = -1;
  		return;
  	}
  	runtime->timer_resolution = (mult * fsize / rate) * post;
  }

  static unsigned long snd_pcm_timer_resolution(struct snd_timer * timer)

  {

  	struct snd_pcm_substream *substream;

  	
  	substream = timer->private_data;
  	return substream->runtime ? substream->runtime->timer_resolution : 0;
  }

  static int snd_pcm_timer_start(struct snd_timer * timer)

  {

  	struct snd_pcm_substream *substream;

  	
  	substream = snd_timer_chip(timer);

  	substream->timer_running = 1;

  	return 0;
  }

  static int snd_pcm_timer_stop(struct snd_timer * timer)

  {

  	struct snd_pcm_substream *substream;

  	
  	substream = snd_timer_chip(timer);

  	substream->timer_running = 0;

  	return 0;
  }

  static struct snd_timer_hardware snd_pcm_timer =

  {
  	.flags =	SNDRV_TIMER_HW_AUTO | SNDRV_TIMER_HW_SLAVE,
  	.resolution =	0,
  	.ticks =	1,
  	.c_resolution =	snd_pcm_timer_resolution,
  	.start =	snd_pcm_timer_start,
  	.stop =		snd_pcm_timer_stop,
  };
  
  /*
   *  Init functions
   */

  static void snd_pcm_timer_free(struct snd_timer *timer)

  {

  	struct snd_pcm_substream *substream = timer->private_data;

  	substream->timer = NULL;
  }

  void snd_pcm_timer_init(struct snd_pcm_substream *substream)

  {

  	struct snd_timer_id tid;
  	struct snd_timer *timer;

  	
  	tid.dev_sclass = SNDRV_TIMER_SCLASS_NONE;
  	tid.dev_class = SNDRV_TIMER_CLASS_PCM;
  	tid.card = substream->pcm->card->number;
  	tid.device = substream->pcm->device;
  	tid.subdevice = (substream->number << 1) | (substream->stream & 1);
  	if (snd_timer_new(substream->pcm->card, "PCM", &tid, &timer) < 0)
  		return;
  	sprintf(timer->name, "PCM %s %i-%i-%i",
  			substream->stream == SNDRV_PCM_STREAM_CAPTURE ?
  				"capture" : "playback",
  			tid.card, tid.device, tid.subdevice);
  	timer->hw = snd_pcm_timer;
  	if (snd_device_register(timer->card, timer) < 0) {
  		snd_device_free(timer->card, timer);
  		return;
  	}
  	timer->private_data = substream;
  	timer->private_free = snd_pcm_timer_free;
  	substream->timer = timer;
  }

  void snd_pcm_timer_done(struct snd_pcm_substream *substream)

  {
  	if (substream->timer) {
  		snd_device_free(substream->pcm->card, substream->timer);
  		substream->timer = NULL;
  	}
  }