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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * Linear conversion Plug-In
Jaroslav Kyselac1017a42007-10-15 09:50:19 +02003 * Copyright (c) 1999 by Jaroslav Kysela <perex@perex.cz>,
Linus Torvalds1da177e2005-04-16 15:20:36 -07004 * Abramo Bagnara <abramo@alsa-project.org>
5 *
6 *
7 * This library is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU Library General Public License as
9 * published by the Free Software Foundation; either version 2 of
10 * the License, or (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU Library General Public License for more details.
16 *
17 * You should have received a copy of the GNU Library General Public
18 * License along with this library; if not, write to the Free Software
19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20 *
21 */
22
23#include <sound/driver.h>
24#include <linux/time.h>
25#include <sound/core.h>
26#include <sound/pcm.h>
27#include "pcm_plugin.h"
28
29/*
30 * Basic linear conversion plugin
31 */
32
Takashi Iwai6ac77bc2005-11-17 14:01:49 +010033struct linear_priv {
Takashi Iwai9390ec82007-08-08 15:50:58 +020034 int cvt_endian; /* need endian conversion? */
35 unsigned int src_ofs; /* byte offset in source format */
36 unsigned int dst_ofs; /* byte soffset in destination format */
37 unsigned int copy_ofs; /* byte offset in temporary u32 data */
38 unsigned int dst_bytes; /* byte size of destination format */
39 unsigned int copy_bytes; /* bytes to copy per conversion */
40 unsigned int flip; /* MSB flip for signeness, done after endian conv */
Takashi Iwai6ac77bc2005-11-17 14:01:49 +010041};
Linus Torvalds1da177e2005-04-16 15:20:36 -070042
Takashi Iwai9390ec82007-08-08 15:50:58 +020043static inline void do_convert(struct linear_priv *data,
44 unsigned char *dst, unsigned char *src)
45{
46 unsigned int tmp = 0;
47 unsigned char *p = (unsigned char *)&tmp;
48
49 memcpy(p + data->copy_ofs, src + data->src_ofs, data->copy_bytes);
50 if (data->cvt_endian)
51 tmp = swab32(tmp);
52 tmp ^= data->flip;
53 memcpy(dst, p + data->dst_ofs, data->dst_bytes);
54}
55
Takashi Iwai6ac77bc2005-11-17 14:01:49 +010056static void convert(struct snd_pcm_plugin *plugin,
57 const struct snd_pcm_plugin_channel *src_channels,
58 struct snd_pcm_plugin_channel *dst_channels,
Linus Torvalds1da177e2005-04-16 15:20:36 -070059 snd_pcm_uframes_t frames)
60{
Takashi Iwai6ac77bc2005-11-17 14:01:49 +010061 struct linear_priv *data = (struct linear_priv *)plugin->extra_data;
Linus Torvalds1da177e2005-04-16 15:20:36 -070062 int channel;
63 int nchannels = plugin->src_format.channels;
64 for (channel = 0; channel < nchannels; ++channel) {
65 char *src;
66 char *dst;
67 int src_step, dst_step;
68 snd_pcm_uframes_t frames1;
69 if (!src_channels[channel].enabled) {
70 if (dst_channels[channel].wanted)
71 snd_pcm_area_silence(&dst_channels[channel].area, 0, frames, plugin->dst_format.format);
72 dst_channels[channel].enabled = 0;
73 continue;
74 }
75 dst_channels[channel].enabled = 1;
76 src = src_channels[channel].area.addr + src_channels[channel].area.first / 8;
77 dst = dst_channels[channel].area.addr + dst_channels[channel].area.first / 8;
78 src_step = src_channels[channel].area.step / 8;
79 dst_step = dst_channels[channel].area.step / 8;
80 frames1 = frames;
81 while (frames1-- > 0) {
Takashi Iwai9390ec82007-08-08 15:50:58 +020082 do_convert(data, dst, src);
Linus Torvalds1da177e2005-04-16 15:20:36 -070083 src += src_step;
84 dst += dst_step;
85 }
86 }
87}
88
Takashi Iwai6ac77bc2005-11-17 14:01:49 +010089static snd_pcm_sframes_t linear_transfer(struct snd_pcm_plugin *plugin,
90 const struct snd_pcm_plugin_channel *src_channels,
91 struct snd_pcm_plugin_channel *dst_channels,
Linus Torvalds1da177e2005-04-16 15:20:36 -070092 snd_pcm_uframes_t frames)
93{
Takashi Iwai6ac77bc2005-11-17 14:01:49 +010094 struct linear_priv *data;
Linus Torvalds1da177e2005-04-16 15:20:36 -070095
96 snd_assert(plugin != NULL && src_channels != NULL && dst_channels != NULL, return -ENXIO);
Takashi Iwai6ac77bc2005-11-17 14:01:49 +010097 data = (struct linear_priv *)plugin->extra_data;
Linus Torvalds1da177e2005-04-16 15:20:36 -070098 if (frames == 0)
99 return 0;
100#ifdef CONFIG_SND_DEBUG
101 {
102 unsigned int channel;
103 for (channel = 0; channel < plugin->src_format.channels; channel++) {
104 snd_assert(src_channels[channel].area.first % 8 == 0 &&
105 src_channels[channel].area.step % 8 == 0,
106 return -ENXIO);
107 snd_assert(dst_channels[channel].area.first % 8 == 0 &&
108 dst_channels[channel].area.step % 8 == 0,
109 return -ENXIO);
110 }
111 }
112#endif
113 convert(plugin, src_channels, dst_channels, frames);
114 return frames;
115}
116
Takashi Iwai9390ec82007-08-08 15:50:58 +0200117static void init_data(struct linear_priv *data, int src_format, int dst_format)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700118{
Takashi Iwai9390ec82007-08-08 15:50:58 +0200119 int src_le, dst_le, src_bytes, dst_bytes;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700120
Takashi Iwai9390ec82007-08-08 15:50:58 +0200121 src_bytes = snd_pcm_format_width(src_format) / 8;
122 dst_bytes = snd_pcm_format_width(dst_format) / 8;
123 src_le = snd_pcm_format_little_endian(src_format) > 0;
124 dst_le = snd_pcm_format_little_endian(dst_format) > 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700125
Takashi Iwai9390ec82007-08-08 15:50:58 +0200126 data->dst_bytes = dst_bytes;
127 data->cvt_endian = src_le != dst_le;
128 data->copy_bytes = src_bytes < dst_bytes ? src_bytes : dst_bytes;
129 if (src_le) {
130 data->copy_ofs = 4 - data->copy_bytes;
131 data->src_ofs = src_bytes - data->copy_bytes;
132 } else
133 data->src_ofs = snd_pcm_format_physical_width(src_format) / 8 -
134 src_bytes;
135 if (dst_le)
136 data->dst_ofs = 4 - data->dst_bytes;
137 else
138 data->dst_ofs = snd_pcm_format_physical_width(dst_format) / 8 -
139 dst_bytes;
140 if (snd_pcm_format_signed(src_format) !=
141 snd_pcm_format_signed(dst_format)) {
142 if (dst_le)
143 data->flip = cpu_to_le32(0x80000000);
144 else
145 data->flip = cpu_to_be32(0x80000000);
146 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700147}
148
Takashi Iwai6ac77bc2005-11-17 14:01:49 +0100149int snd_pcm_plugin_build_linear(struct snd_pcm_substream *plug,
150 struct snd_pcm_plugin_format *src_format,
151 struct snd_pcm_plugin_format *dst_format,
152 struct snd_pcm_plugin **r_plugin)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700153{
154 int err;
Takashi Iwai6ac77bc2005-11-17 14:01:49 +0100155 struct linear_priv *data;
156 struct snd_pcm_plugin *plugin;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700157
158 snd_assert(r_plugin != NULL, return -ENXIO);
159 *r_plugin = NULL;
160
161 snd_assert(src_format->rate == dst_format->rate, return -ENXIO);
162 snd_assert(src_format->channels == dst_format->channels, return -ENXIO);
163 snd_assert(snd_pcm_format_linear(src_format->format) &&
164 snd_pcm_format_linear(dst_format->format), return -ENXIO);
165
166 err = snd_pcm_plugin_build(plug, "linear format conversion",
167 src_format, dst_format,
Takashi Iwai6ac77bc2005-11-17 14:01:49 +0100168 sizeof(struct linear_priv), &plugin);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700169 if (err < 0)
170 return err;
Takashi Iwai6ac77bc2005-11-17 14:01:49 +0100171 data = (struct linear_priv *)plugin->extra_data;
Takashi Iwai9390ec82007-08-08 15:50:58 +0200172 init_data(data, src_format->format, dst_format->format);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700173 plugin->transfer = linear_transfer;
174 *r_plugin = plugin;
175 return 0;
176}