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#include "pcm_local.h"
  29
  30/*
  31 *  Timer functions
  32 */
  33
  34void snd_pcm_timer_resolution_change(struct snd_pcm_substream *substream)
  35{
  36        unsigned long rate, mult, fsize, l, post;
  37        struct snd_pcm_runtime *runtime = substream->runtime;
  38
  39        mult = 1000000000;
  40        rate = runtime->rate;
  41        if (snd_BUG_ON(!rate))
  42                return;
  43        l = gcd(mult, rate);
  44        mult /= l;
  45        rate /= l;
  46        fsize = runtime->period_size;
  47        if (snd_BUG_ON(!fsize))
  48                return;
  49        l = gcd(rate, fsize);
  50        rate /= l;
  51        fsize /= l;
  52        post = 1;
  53        while ((mult * fsize) / fsize != mult) {
  54                mult /= 2;
  55                post *= 2;
  56        }
  57        if (rate == 0) {
  58                pcm_err(substream->pcm,
  59                        "pcm timer resolution out of range (rate = %u, period_size = %lu)\n",
  60                        runtime->rate, runtime->period_size);
  61                runtime->timer_resolution = -1;
  62                return;
  63        }
  64        runtime->timer_resolution = (mult * fsize / rate) * post;
  65}
  66
  67static unsigned long snd_pcm_timer_resolution(struct snd_timer * timer)
  68{
  69        struct snd_pcm_substream *substream;
  70
  71        substream = timer->private_data;
  72        return substream->runtime ? substream->runtime->timer_resolution : 0;
  73}
  74
  75static int snd_pcm_timer_start(struct snd_timer * timer)
  76{
  77        struct snd_pcm_substream *substream;
  78
  79        substream = snd_timer_chip(timer);
  80        substream->timer_running = 1;
  81        return 0;
  82}
  83
  84static int snd_pcm_timer_stop(struct snd_timer * timer)
  85{
  86        struct snd_pcm_substream *substream;
  87
  88        substream = snd_timer_chip(timer);
  89        substream->timer_running = 0;
  90        return 0;
  91}
  92
  93static struct snd_timer_hardware snd_pcm_timer =
  94{
  95        .flags =        SNDRV_TIMER_HW_AUTO | SNDRV_TIMER_HW_SLAVE,
  96        .resolution =   0,
  97        .ticks =        1,
  98        .c_resolution = snd_pcm_timer_resolution,
  99        .start =        snd_pcm_timer_start,
 100        .stop =         snd_pcm_timer_stop,
 101};
 102
 103/*
 104 *  Init functions
 105 */
 106
 107static void snd_pcm_timer_free(struct snd_timer *timer)
 108{
 109        struct snd_pcm_substream *substream = timer->private_data;
 110        substream->timer = NULL;
 111}
 112
 113void snd_pcm_timer_init(struct snd_pcm_substream *substream)
 114{
 115        struct snd_timer_id tid;
 116        struct snd_timer *timer;
 117
 118        tid.dev_sclass = SNDRV_TIMER_SCLASS_NONE;
 119        tid.dev_class = SNDRV_TIMER_CLASS_PCM;
 120        tid.card = substream->pcm->card->number;
 121        tid.device = substream->pcm->device;
 122        tid.subdevice = (substream->number << 1) | (substream->stream & 1);
 123        if (snd_timer_new(substream->pcm->card, "PCM", &tid, &timer) < 0)
 124                return;
 125        sprintf(timer->name, "PCM %s %i-%i-%i",
 126                        substream->stream == SNDRV_PCM_STREAM_CAPTURE ?
 127                                "capture" : "playback",
 128                        tid.card, tid.device, tid.subdevice);
 129        timer->hw = snd_pcm_timer;
 130        if (snd_device_register(timer->card, timer) < 0) {
 131                snd_device_free(timer->card, timer);
 132                return;
 133        }
 134        timer->private_data = substream;
 135        timer->private_free = snd_pcm_timer_free;
 136        substream->timer = timer;
 137}
 138
 139void snd_pcm_timer_done(struct snd_pcm_substream *substream)
 140{
 141        if (substream->timer) {
 142                snd_device_free(substream->pcm->card, substream->timer);
 143                substream->timer = NULL;
 144        }
 145}
 146