Root/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 
37static 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 
63static 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 
90static 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
108int 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}
142

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