root/sound/core/oss/io.c

DEFINITIONS

1. io_playback_transfer
2. io_capture_transfer
3. io_src_channels
4. snd_pcm_plugin_build_io

   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)
  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)
  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         if (snd_BUG_ON(!plugin))
  43                 return -ENXIO;
  44         if (snd_BUG_ON(!src_channels))
  45                 return -ENXIO;
  46         if (plugin->access == SNDRV_PCM_ACCESS_RW_INTERLEAVED) {
  47                 return pcm_write(plugin->plug, src_channels->area.addr, frames);
  48         } else {
  49                 int channel, channels = plugin->dst_format.channels;
  50                 void **bufs = (void**)plugin->extra_data;
  51                 if (snd_BUG_ON(!bufs))
  52                         return -ENXIO;
  53                 for (channel = 0; channel < channels; channel++) {
  54                         if (src_channels[channel].enabled)
  55                                 bufs[channel] = src_channels[channel].area.addr;
  56                         else
  57                                 bufs[channel] = NULL;
  58                 }
  59                 return pcm_writev(plugin->plug, bufs, frames);
  60         }
  61 }
  62  
  63 static snd_pcm_sframes_t io_capture_transfer(struct snd_pcm_plugin *plugin,
  64                                    const struct snd_pcm_plugin_channel *src_channels,
  65                                    struct snd_pcm_plugin_channel *dst_channels,
  66                                    snd_pcm_uframes_t frames)
  67 {
  68         if (snd_BUG_ON(!plugin))
  69                 return -ENXIO;
  70         if (snd_BUG_ON(!dst_channels))
  71                 return -ENXIO;
  72         if (plugin->access == SNDRV_PCM_ACCESS_RW_INTERLEAVED) {
  73                 return pcm_read(plugin->plug, dst_channels->area.addr, frames);
  74         } else {
  75                 int channel, channels = plugin->dst_format.channels;
  76                 void **bufs = (void**)plugin->extra_data;
  77                 if (snd_BUG_ON(!bufs))
  78                         return -ENXIO;
  79                 for (channel = 0; channel < channels; channel++) {
  80                         if (dst_channels[channel].enabled)
  81                                 bufs[channel] = dst_channels[channel].area.addr;
  82                         else
  83                                 bufs[channel] = NULL;
  84                 }
  85                 return pcm_readv(plugin->plug, bufs, frames);
  86         }
  87         return 0;
  88 }
  89  
  90 static snd_pcm_sframes_t io_src_channels(struct snd_pcm_plugin *plugin,
  91                              snd_pcm_uframes_t frames,
  92                              struct snd_pcm_plugin_channel **channels)
  93 {
  94         int err;
  95         unsigned int channel;
  96         struct snd_pcm_plugin_channel *v;
  97         err = snd_pcm_plugin_client_channels(plugin, frames, &v);
  98         if (err < 0)
  99                 return err;
 100         *channels = v;
 101         if (plugin->access == SNDRV_PCM_ACCESS_RW_INTERLEAVED) {
 102                 for (channel = 0; channel < plugin->src_format.channels; ++channel, ++v)
 103                         v->wanted = 1;
 104         }
 105         return frames;
 106 }
 107 
 108 int snd_pcm_plugin_build_io(struct snd_pcm_substream *plug,
 109                             struct snd_pcm_hw_params *params,
 110                             struct snd_pcm_plugin **r_plugin)
 111 {
 112         int err;
 113         struct snd_pcm_plugin_format format;
 114         struct snd_pcm_plugin *plugin;
 115 
 116         if (snd_BUG_ON(!r_plugin))
 117                 return -ENXIO;
 118         *r_plugin = NULL;
 119         if (snd_BUG_ON(!plug || !params))
 120                 return -ENXIO;
 121         format.format = params_format(params);
 122         format.rate = params_rate(params);
 123         format.channels = params_channels(params);
 124         err = snd_pcm_plugin_build(plug, "I/O io",
 125                                    &format, &format,
 126                                    sizeof(void *) * format.channels,
 127                                    &plugin);
 128         if (err < 0)
 129                 return err;
 130         plugin->access = params_access(params);
 131         if (snd_pcm_plug_stream(plug) == SNDRV_PCM_STREAM_PLAYBACK) {
 132                 plugin->transfer = io_playback_transfer;
 133                 if (plugin->access == SNDRV_PCM_ACCESS_RW_INTERLEAVED)
 134                         plugin->client_channels = io_src_channels;
 135         } else {
 136                 plugin->transfer = io_capture_transfer;
 137         }
 138 
 139         *r_plugin = plugin;
 140         return 0;
 141 }