1 // SPDX-License-Identifier: LGPL-2.0+
2 /*
3 * Linear conversion Plug-In
4 * Copyright (c) 2000 by Abramo Bagnara <abramo@alsa-project.org>
5 */
6
7 #include <linux/time.h>
8 #include <sound/core.h>
9 #include <sound/pcm.h>
10 #include "pcm_plugin.h"
11
copy_transfer(struct snd_pcm_plugin * plugin,const struct snd_pcm_plugin_channel * src_channels,struct snd_pcm_plugin_channel * dst_channels,snd_pcm_uframes_t frames)12 static snd_pcm_sframes_t copy_transfer(struct snd_pcm_plugin *plugin,
13 const struct snd_pcm_plugin_channel *src_channels,
14 struct snd_pcm_plugin_channel *dst_channels,
15 snd_pcm_uframes_t frames)
16 {
17 unsigned int channel;
18 unsigned int nchannels;
19
20 if (snd_BUG_ON(!plugin || !src_channels || !dst_channels))
21 return -ENXIO;
22 if (frames == 0)
23 return 0;
24 nchannels = plugin->src_format.channels;
25 for (channel = 0; channel < nchannels; channel++) {
26 if (snd_BUG_ON(src_channels->area.first % 8 ||
27 src_channels->area.step % 8))
28 return -ENXIO;
29 if (snd_BUG_ON(dst_channels->area.first % 8 ||
30 dst_channels->area.step % 8))
31 return -ENXIO;
32 if (!src_channels->enabled) {
33 if (dst_channels->wanted)
34 snd_pcm_area_silence(&dst_channels->area, 0, frames, plugin->dst_format.format);
35 dst_channels->enabled = 0;
36 continue;
37 }
38 dst_channels->enabled = 1;
39 snd_pcm_area_copy(&src_channels->area, 0, &dst_channels->area, 0, frames, plugin->src_format.format);
40 src_channels++;
41 dst_channels++;
42 }
43 return frames;
44 }
45
snd_pcm_plugin_build_copy(struct snd_pcm_substream * plug,struct snd_pcm_plugin_format * src_format,struct snd_pcm_plugin_format * dst_format,struct snd_pcm_plugin ** r_plugin)46 int snd_pcm_plugin_build_copy(struct snd_pcm_substream *plug,
47 struct snd_pcm_plugin_format *src_format,
48 struct snd_pcm_plugin_format *dst_format,
49 struct snd_pcm_plugin **r_plugin)
50 {
51 int err;
52 struct snd_pcm_plugin *plugin;
53 int width;
54
55 if (snd_BUG_ON(!r_plugin))
56 return -ENXIO;
57 *r_plugin = NULL;
58
59 if (snd_BUG_ON(src_format->format != dst_format->format))
60 return -ENXIO;
61 if (snd_BUG_ON(src_format->rate != dst_format->rate))
62 return -ENXIO;
63 if (snd_BUG_ON(src_format->channels != dst_format->channels))
64 return -ENXIO;
65
66 width = snd_pcm_format_physical_width(src_format->format);
67 if (snd_BUG_ON(width <= 0))
68 return -ENXIO;
69
70 err = snd_pcm_plugin_build(plug, "copy", src_format, dst_format,
71 0, &plugin);
72 if (err < 0)
73 return err;
74 plugin->transfer = copy_transfer;
75 *r_plugin = plugin;
76 return 0;
77 }
78