git.oblomov.eu Git - linux-2.6/blob - sound/core/oss/io.c

   1 /*
   2  *  PCM I/O Plug-In Interface
   3  *  Copyright (c) 1999 by Jaroslav Kysela <perex@perex.cz>
   4  *
   5  *
   6  *   This library is free software; you can redistribute it and/or modify
   7  *   it under the terms of the GNU Library General Public License as
   8  *   published by the Free Software Foundation; either version 2 of
   9  *   the License, or (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 Library General Public License for more details.
  15  *
  16  *   You should have received a copy of the GNU Library General Public
  17  *   License along with this library; 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 <sound/core.h>
  24 #include <sound/pcm.h>
  25 #include <sound/pcm_params.h>
  26 #include "pcm_plugin.h"
  27
  28 #define pcm_write(plug,buf,count) snd_pcm_oss_write3(plug,buf,count,1)
  29 #define pcm_writev(plug,vec,count) snd_pcm_oss_writev3(plug,vec,count,1)
  30 #define pcm_read(plug,buf,count) snd_pcm_oss_read3(plug,buf,count,1)
  31 #define pcm_readv(plug,vec,count) snd_pcm_oss_readv3(plug,vec,count,1)
  32
  33 /*
  34  *  Basic io plugin
  35  */
  36
  37 static snd_pcm_sframes_t io_playback_transfer(struct snd_pcm_plugin *plugin,
  38                                     const struct snd_pcm_plugin_channel *src_channels,
  39                                     struct snd_pcm_plugin_channel *dst_channels,
  40                                     snd_pcm_uframes_t frames)
  41 {
  42         snd_assert(plugin != NULL, return -ENXIO);
  43         snd_assert(src_channels != NULL, return -ENXIO);
  44         if (plugin->access == SNDRV_PCM_ACCESS_RW_INTERLEAVED) {
  45                 return pcm_write(plugin->plug, src_channels->area.addr, frames);
  46         } else {
  47                 int channel, channels = plugin->dst_format.channels;
  48                 void **bufs = (void**)plugin->extra_data;
  49                 snd_assert(bufs != NULL, return -ENXIO);
  50                 for (channel = 0; channel < channels; channel++) {
  51                         if (src_channels[channel].enabled)
  52                                 bufs[channel] = src_channels[channel].area.addr;
  53                         else
  54                                 bufs[channel] = NULL;
  55                 }
  56                 return pcm_writev(plugin->plug, bufs, frames);
  57         }
  58 }
  59
  60 static snd_pcm_sframes_t io_capture_transfer(struct snd_pcm_plugin *plugin,
  61                                    const struct snd_pcm_plugin_channel *src_channels,
  62                                    struct snd_pcm_plugin_channel *dst_channels,
  63                                    snd_pcm_uframes_t frames)
  64 {
  65         snd_assert(plugin != NULL, return -ENXIO);
  66         snd_assert(dst_channels != NULL, return -ENXIO);
  67         if (plugin->access == SNDRV_PCM_ACCESS_RW_INTERLEAVED) {
  68                 return pcm_read(plugin->plug, dst_channels->area.addr, frames);
  69         } else {
  70                 int channel, channels = plugin->dst_format.channels;
  71                 void **bufs = (void**)plugin->extra_data;
  72                 snd_assert(bufs != NULL, return -ENXIO);
  73                 for (channel = 0; channel < channels; channel++) {
  74                         if (dst_channels[channel].enabled)
  75                                 bufs[channel] = dst_channels[channel].area.addr;
  76                         else
  77                                 bufs[channel] = NULL;
  78                 }
  79                 return pcm_readv(plugin->plug, bufs, frames);
  80         }
  81         return 0;
  82 }
  83
  84 static snd_pcm_sframes_t io_src_channels(struct snd_pcm_plugin *plugin,
  85                              snd_pcm_uframes_t frames,
  86                              struct snd_pcm_plugin_channel **channels)
  87 {
  88         int err;
  89         unsigned int channel;
  90         struct snd_pcm_plugin_channel *v;
  91         err = snd_pcm_plugin_client_channels(plugin, frames, &v);
  92         if (err < 0)
  93                 return err;
  94         *channels = v;
  95         if (plugin->access == SNDRV_PCM_ACCESS_RW_INTERLEAVED) {
  96                 for (channel = 0; channel < plugin->src_format.channels; ++channel, ++v)
  97                         v->wanted = 1;
  98         }
  99         return frames;
 100 }
 101
 102 int snd_pcm_plugin_build_io(struct snd_pcm_substream *plug,
 103                             struct snd_pcm_hw_params *params,
 104                             struct snd_pcm_plugin **r_plugin)
 105 {
 106         int err;
 107         struct snd_pcm_plugin_format format;
 108         struct snd_pcm_plugin *plugin;
 109
 110         snd_assert(r_plugin != NULL, return -ENXIO);
 111         *r_plugin = NULL;
 112         snd_assert(plug != NULL && params != NULL, return -ENXIO);
 113         format.format = params_format(params);
 114         format.rate = params_rate(params);
 115         format.channels = params_channels(params);
 116         err = snd_pcm_plugin_build(plug, "I/O io",
 117                                    &format, &format,
 118                                    sizeof(void *) * format.channels,
 119                                    &plugin);
 120         if (err < 0)
 121                 return err;
 122         plugin->access = params_access(params);
 123         if (snd_pcm_plug_stream(plug) == SNDRV_PCM_STREAM_PLAYBACK) {
 124                 plugin->transfer = io_playback_transfer;
 125                 if (plugin->access == SNDRV_PCM_ACCESS_RW_INTERLEAVED)
 126                         plugin->client_channels = io_src_channels;
 127         } else {
 128                 plugin->transfer = io_capture_transfer;
 129         }
 130
 131         *r_plugin = plugin;
 132         return 0;
 133 }