LXR linux/sound/core/pcm

   1/*
   2 *  Digital Audio (PCM) abstract layer
   3 *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
   4 *
   5 *
   6 *   This program is free software; you can redistribute it and/or modify
   7 *   it under the terms of the GNU General Public License as published by
   8 *   the Free Software Foundation; either version 2 of the License, or
   9 *   (at your option) any later version.
  10 *
  11 *   This program is distributed in the hope that it will be useful,
  12 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 *   GNU General Public License for more details.
  15 *
  16 *   You should have received a copy of the GNU General Public License
  17 *   along with this program; if not, write to the Free Software
  18 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
  19 *
  20 */
  21
  22#include <linux/time.h>
  23#include <linux/gcd.h>
  24#include <sound/core.h>
  25#include <sound/pcm.h>
  26#include <sound/timer.h>
  27
  28/*
  29 *  Timer functions
  30 */
  31
  32void snd_pcm_timer_resolution_change(struct snd_pcm_substream *substream)
  33{
  34        unsigned long rate, mult, fsize, l, post;
  35        struct snd_pcm_runtime *runtime = substream->runtime;
  36        
  37        mult = 1000000000;
  38        rate = runtime->rate;
  39        if (snd_BUG_ON(!rate))
  40                return;
  41        l = gcd(mult, rate);
  42        mult /= l;
  43        rate /= l;
  44        fsize = runtime->period_size;
  45        if (snd_BUG_ON(!fsize))
  46                return;
  47        l = gcd(rate, fsize);
  48        rate /= l;
  49        fsize /= l;
  50        post = 1;
  51        while ((mult * fsize) / fsize != mult) {
  52                mult /= 2;
  53                post *= 2;
  54        }
  55        if (rate == 0) {
  56                pcm_err(substream->pcm,
  57                        "pcm timer resolution out of range (rate = %u, period_size = %lu)\n",
  58                        runtime->rate, runtime->period_size);
  59                runtime->timer_resolution = -1;
  60                return;
  61        }
  62        runtime->timer_resolution = (mult * fsize / rate) * post;
  63}
  64
  65static unsigned long snd_pcm_timer_resolution(struct snd_timer * timer)
  66{
  67        struct snd_pcm_substream *substream;
  68        
  69        substream = timer->private_data;
  70        return substream->runtime ? substream->runtime->timer_resolution : 0;
  71}
  72
  73static int snd_pcm_timer_start(struct snd_timer * timer)
  74{
  75        struct snd_pcm_substream *substream;
  76        
  77        substream = snd_timer_chip(timer);
  78        substream->timer_running = 1;
  79        return 0;
  80}
  81
  82static int snd_pcm_timer_stop(struct snd_timer * timer)
  83{
  84        struct snd_pcm_substream *substream;
  85        
  86        substream = snd_timer_chip(timer);
  87        substream->timer_running = 0;
  88        return 0;
  89}
  90
  91static struct snd_timer_hardware snd_pcm_timer =
  92{
  93        .flags =        SNDRV_TIMER_HW_AUTO | SNDRV_TIMER_HW_SLAVE,
  94        .resolution =   0,
  95        .ticks =        1,
  96        .c_resolution = snd_pcm_timer_resolution,
  97        .start =        snd_pcm_timer_start,
  98        .stop =         snd_pcm_timer_stop,
  99};
 100
 101/*
 102 *  Init functions
 103 */
 104
 105static void snd_pcm_timer_free(struct snd_timer *timer)
 106{
 107        struct snd_pcm_substream *substream = timer->private_data;
 108        substream->timer = NULL;
 109}
 110
 111void snd_pcm_timer_init(struct snd_pcm_substream *substream)
 112{
 113        struct snd_timer_id tid;
 114        struct snd_timer *timer;
 115        
 116        tid.dev_sclass = SNDRV_TIMER_SCLASS_NONE;
 117        tid.dev_class = SNDRV_TIMER_CLASS_PCM;
 118        tid.card = substream->pcm->card->number;
 119        tid.device = substream->pcm->device;
 120        tid.subdevice = (substream->number << 1) | (substream->stream & 1);
 121        if (snd_timer_new(substream->pcm->card, "PCM", &tid, &timer) < 0)
 122                return;
 123        sprintf(timer->name, "PCM %s %i-%i-%i",
 124                        substream->stream == SNDRV_PCM_STREAM_CAPTURE ?
 125                                "capture" : "playback",
 126                        tid.card, tid.device, tid.subdevice);
 127        timer->hw = snd_pcm_timer;
 128        if (snd_device_register(timer->card, timer) < 0) {
 129                snd_device_free(timer->card, timer);
 130                return;
 131        }
 132        timer->private_data = substream;
 133        timer->private_free = snd_pcm_timer_free;
 134        substream->timer = timer;
 135}
 136
 137void snd_pcm_timer_done(struct snd_pcm_substream *substream)
 138{
 139        if (substream->timer) {
 140                snd_device_free(substream->pcm->card, substream->timer);
 141                substream->timer = NULL;
 142        }
 143}
 144