core/oss/io.c

0001 /*
0002  *  PCM I/O Plug-In Interface
0003  *  Copyright (c) 1999 by Jaroslav Kysela <perex@perex.cz>
0004  *
0005  *
0006  *   This library is free software; you can redistribute it and/or modify
0007  *   it under the terms of the GNU Library General Public License as
0008  *   published by the Free Software Foundation; either version 2 of
0009  *   the License, or (at your option) any later version.
0010  *
0011  *   This program is distributed in the hope that it will be useful,
0012  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
0013  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
0014  *   GNU Library General Public License for more details.
0015  *
0016  *   You should have received a copy of the GNU Library General Public
0017  *   License along with this library; if not, write to the Free Software
0018  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
0019  *
0020  */
0021
0022 #include <linux/time.h>
0023 #include <sound/core.h>
0024 #include <sound/pcm.h>
0025 #include <sound/pcm_params.h>
0026 #include "pcm_plugin.h"
0027
0028 #define pcm_write(plug,buf,count) snd_pcm_oss_write3(plug,buf,count,1)
0029 #define pcm_writev(plug,vec,count) snd_pcm_oss_writev3(plug,vec,count)
0030 #define pcm_read(plug,buf,count) snd_pcm_oss_read3(plug,buf,count,1)
0031 #define pcm_readv(plug,vec,count) snd_pcm_oss_readv3(plug,vec,count)
0032
0033 /*
0034  *  Basic io plugin
0035  */
0036
0037 static snd_pcm_sframes_t io_playback_transfer(struct snd_pcm_plugin *plugin,
0038                     const struct snd_pcm_plugin_channel *src_channels,
0039                     struct snd_pcm_plugin_channel *dst_channels,
0040                     snd_pcm_uframes_t frames)
0041 {
0042     if (snd_BUG_ON(!plugin))
0043         return -ENXIO;
0044     if (snd_BUG_ON(!src_channels))
0045         return -ENXIO;
0046     if (plugin->access == SNDRV_PCM_ACCESS_RW_INTERLEAVED) {
0047         return pcm_write(plugin->plug, src_channels->area.addr, frames);
0048     } else {
0049         int channel, channels = plugin->dst_format.channels;
0050         void **bufs = (void**)plugin->extra_data;
0051         if (snd_BUG_ON(!bufs))
0052             return -ENXIO;
0053         for (channel = 0; channel < channels; channel++) {
0054             if (src_channels[channel].enabled)
0055                 bufs[channel] = src_channels[channel].area.addr;
0056             else
0057                 bufs[channel] = NULL;
0058         }
0059         return pcm_writev(plugin->plug, bufs, frames);
0060     }
0061 }
0062
0063 static snd_pcm_sframes_t io_capture_transfer(struct snd_pcm_plugin *plugin,
0064                    const struct snd_pcm_plugin_channel *src_channels,
0065                    struct snd_pcm_plugin_channel *dst_channels,
0066                    snd_pcm_uframes_t frames)
0067 {
0068     if (snd_BUG_ON(!plugin))
0069         return -ENXIO;
0070     if (snd_BUG_ON(!dst_channels))
0071         return -ENXIO;
0072     if (plugin->access == SNDRV_PCM_ACCESS_RW_INTERLEAVED) {
0073         return pcm_read(plugin->plug, dst_channels->area.addr, frames);
0074     } else {
0075         int channel, channels = plugin->dst_format.channels;
0076         void **bufs = (void**)plugin->extra_data;
0077         if (snd_BUG_ON(!bufs))
0078             return -ENXIO;
0079         for (channel = 0; channel < channels; channel++) {
0080             if (dst_channels[channel].enabled)
0081                 bufs[channel] = dst_channels[channel].area.addr;
0082             else
0083                 bufs[channel] = NULL;
0084         }
0085         return pcm_readv(plugin->plug, bufs, frames);
0086     }
0087     return 0;
0088 }
0089
0090 static snd_pcm_sframes_t io_src_channels(struct snd_pcm_plugin *plugin,
0091                  snd_pcm_uframes_t frames,
0092                  struct snd_pcm_plugin_channel **channels)
0093 {
0094     int err;
0095     unsigned int channel;
0096     struct snd_pcm_plugin_channel *v;
0097     err = snd_pcm_plugin_client_channels(plugin, frames, &v);
0098     if (err < 0)
0099         return err;
0100     *channels = v;
0101     if (plugin->access == SNDRV_PCM_ACCESS_RW_INTERLEAVED) {
0102         for (channel = 0; channel < plugin->src_format.channels; ++channel, ++v)
0103             v->wanted = 1;
0104     }
0105     return frames;
0106 }
0107
0108 int snd_pcm_plugin_build_io(struct snd_pcm_substream *plug,
0109                 struct snd_pcm_hw_params *params,
0110                 struct snd_pcm_plugin **r_plugin)
0111 {
0112     int err;
0113     struct snd_pcm_plugin_format format;
0114     struct snd_pcm_plugin *plugin;
0115
0116     if (snd_BUG_ON(!r_plugin))
0117         return -ENXIO;
0118     *r_plugin = NULL;
0119     if (snd_BUG_ON(!plug || !params))
0120         return -ENXIO;
0121     format.format = params_format(params);
0122     format.rate = params_rate(params);
0123     format.channels = params_channels(params);
0124     err = snd_pcm_plugin_build(plug, "I/O io",
0125                    &format, &format,
0126                    sizeof(void *) * format.channels,
0127                    &plugin);
0128     if (err < 0)
0129         return err;
0130     plugin->access = params_access(params);
0131     if (snd_pcm_plug_stream(plug) == SNDRV_PCM_STREAM_PLAYBACK) {
0132         plugin->transfer = io_playback_transfer;
0133         if (plugin->access == SNDRV_PCM_ACCESS_RW_INTERLEAVED)
0134             plugin->client_channels = io_src_channels;
0135     } else {
0136         plugin->transfer = io_capture_transfer;
0137     }
0138
0139     *r_plugin = plugin;
0140     return 0;
0141 }