xref: /openbmc/linux/sound/core/oss/io.c (revision f42b3800)
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 }
134