pcm-indirect.h
5.61 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
/*
* Helper functions for indirect PCM data transfer
*
* Copyright (c) by Takashi Iwai <tiwai@suse.de>
* Jaroslav Kysela <perex@perex.cz>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#ifndef __SOUND_PCM_INDIRECT_H
#define __SOUND_PCM_INDIRECT_H
#include <sound/pcm.h>
struct snd_pcm_indirect {
unsigned int hw_buffer_size; /* Byte size of hardware buffer */
unsigned int hw_queue_size; /* Max queue size of hw buffer (0 = buffer size) */
unsigned int hw_data; /* Offset to next dst (or src) in hw ring buffer */
unsigned int hw_io; /* Ring buffer hw pointer */
int hw_ready; /* Bytes ready for play (or captured) in hw ring buffer */
unsigned int sw_buffer_size; /* Byte size of software buffer */
unsigned int sw_data; /* Offset to next dst (or src) in sw ring buffer */
unsigned int sw_io; /* Current software pointer in bytes */
int sw_ready; /* Bytes ready to be transferred to/from hw */
snd_pcm_uframes_t appl_ptr; /* Last seen appl_ptr */
};
typedef void (*snd_pcm_indirect_copy_t)(struct snd_pcm_substream *substream,
struct snd_pcm_indirect *rec, size_t bytes);
/*
* helper function for playback ack callback
*/
static inline void
snd_pcm_indirect_playback_transfer(struct snd_pcm_substream *substream,
struct snd_pcm_indirect *rec,
snd_pcm_indirect_copy_t copy)
{
struct snd_pcm_runtime *runtime = substream->runtime;
snd_pcm_uframes_t appl_ptr = runtime->control->appl_ptr;
snd_pcm_sframes_t diff = appl_ptr - rec->appl_ptr;
int qsize;
if (diff) {
if (diff < -(snd_pcm_sframes_t) (runtime->boundary / 2))
diff += runtime->boundary;
rec->sw_ready += (int)frames_to_bytes(runtime, diff);
rec->appl_ptr = appl_ptr;
}
qsize = rec->hw_queue_size ? rec->hw_queue_size : rec->hw_buffer_size;
while (rec->hw_ready < qsize && rec->sw_ready > 0) {
unsigned int hw_to_end = rec->hw_buffer_size - rec->hw_data;
unsigned int sw_to_end = rec->sw_buffer_size - rec->sw_data;
unsigned int bytes = qsize - rec->hw_ready;
if (rec->sw_ready < (int)bytes)
bytes = rec->sw_ready;
if (hw_to_end < bytes)
bytes = hw_to_end;
if (sw_to_end < bytes)
bytes = sw_to_end;
if (! bytes)
break;
copy(substream, rec, bytes);
rec->hw_data += bytes;
if (rec->hw_data == rec->hw_buffer_size)
rec->hw_data = 0;
rec->sw_data += bytes;
if (rec->sw_data == rec->sw_buffer_size)
rec->sw_data = 0;
rec->hw_ready += bytes;
rec->sw_ready -= bytes;
}
}
/*
* helper function for playback pointer callback
* ptr = current byte pointer
*/
static inline snd_pcm_uframes_t
snd_pcm_indirect_playback_pointer(struct snd_pcm_substream *substream,
struct snd_pcm_indirect *rec, unsigned int ptr)
{
int bytes = ptr - rec->hw_io;
if (bytes < 0)
bytes += rec->hw_buffer_size;
rec->hw_io = ptr;
rec->hw_ready -= bytes;
rec->sw_io += bytes;
if (rec->sw_io >= rec->sw_buffer_size)
rec->sw_io -= rec->sw_buffer_size;
if (substream->ops->ack)
substream->ops->ack(substream);
return bytes_to_frames(substream->runtime, rec->sw_io);
}
/*
* helper function for capture ack callback
*/
static inline void
snd_pcm_indirect_capture_transfer(struct snd_pcm_substream *substream,
struct snd_pcm_indirect *rec,
snd_pcm_indirect_copy_t copy)
{
struct snd_pcm_runtime *runtime = substream->runtime;
snd_pcm_uframes_t appl_ptr = runtime->control->appl_ptr;
snd_pcm_sframes_t diff = appl_ptr - rec->appl_ptr;
if (diff) {
if (diff < -(snd_pcm_sframes_t) (runtime->boundary / 2))
diff += runtime->boundary;
rec->sw_ready -= frames_to_bytes(runtime, diff);
rec->appl_ptr = appl_ptr;
}
while (rec->hw_ready > 0 &&
rec->sw_ready < (int)rec->sw_buffer_size) {
size_t hw_to_end = rec->hw_buffer_size - rec->hw_data;
size_t sw_to_end = rec->sw_buffer_size - rec->sw_data;
size_t bytes = rec->sw_buffer_size - rec->sw_ready;
if (rec->hw_ready < (int)bytes)
bytes = rec->hw_ready;
if (hw_to_end < bytes)
bytes = hw_to_end;
if (sw_to_end < bytes)
bytes = sw_to_end;
if (! bytes)
break;
copy(substream, rec, bytes);
rec->hw_data += bytes;
if ((int)rec->hw_data == rec->hw_buffer_size)
rec->hw_data = 0;
rec->sw_data += bytes;
if (rec->sw_data == rec->sw_buffer_size)
rec->sw_data = 0;
rec->hw_ready -= bytes;
rec->sw_ready += bytes;
}
}
/*
* helper function for capture pointer callback,
* ptr = current byte pointer
*/
static inline snd_pcm_uframes_t
snd_pcm_indirect_capture_pointer(struct snd_pcm_substream *substream,
struct snd_pcm_indirect *rec, unsigned int ptr)
{
int qsize;
int bytes = ptr - rec->hw_io;
if (bytes < 0)
bytes += rec->hw_buffer_size;
rec->hw_io = ptr;
rec->hw_ready += bytes;
qsize = rec->hw_queue_size ? rec->hw_queue_size : rec->hw_buffer_size;
if (rec->hw_ready > qsize)
return SNDRV_PCM_POS_XRUN;
rec->sw_io += bytes;
if (rec->sw_io >= rec->sw_buffer_size)
rec->sw_io -= rec->sw_buffer_size;
if (substream->ops->ack)
substream->ops->ack(substream);
return bytes_to_frames(substream->runtime, rec->sw_io);
}
#endif /* __SOUND_PCM_INDIRECT_H */