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
|
/*
* Digital Audio (PCM) abstract layer
* Copyright (c) by 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*/
#include <linux/time.h>
#include <sound/core.h>
#include <sound/pcm.h>
#include <sound/timer.h>
/*
* Timer functions
*/
/* Greatest common divisor */
static unsigned long gcd(unsigned long a, unsigned long b)
{
unsigned long r;
if (a < b) {
r = a;
a = b;
b = r;
}
while ((r = a % b) != 0) {
a = b;
b = r;
}
return b;
}
void snd_pcm_timer_resolution_change(struct snd_pcm_substream *substream)
{
unsigned long rate, mult, fsize, l, post;
struct snd_pcm_runtime *runtime = substream->runtime;
mult = 1000000000;
rate = runtime->rate;
if (snd_BUG_ON(!rate))
return;
l = gcd(mult, rate);
mult /= l;
rate /= l;
fsize = runtime->period_size;
if (snd_BUG_ON(!fsize))
return;
l = gcd(rate, fsize);
rate /= l;
fsize /= l;
post = 1;
while ((mult * fsize) / fsize != mult) {
mult /= 2;
post *= 2;
}
if (rate == 0) {
snd_printk(KERN_ERR "pcm timer resolution out of range (rate = %u, period_size = %lu)\n", runtime->rate, runtime->period_size);
runtime->timer_resolution = -1;
return;
}
runtime->timer_resolution = (mult * fsize / rate) * post;
}
static unsigned long snd_pcm_timer_resolution(struct snd_timer * timer)
{
struct snd_pcm_substream *substream;
substream = timer->private_data;
return substream->runtime ? substream->runtime->timer_resolution : 0;
}
static int snd_pcm_timer_start(struct snd_timer * timer)
{
unsigned long flags;
struct snd_pcm_substream *substream;
substream = snd_timer_chip(timer);
spin_lock_irqsave(&substream->timer_lock, flags);
substream->timer_running = 1;
spin_unlock_irqrestore(&substream->timer_lock, flags);
return 0;
}
static int snd_pcm_timer_stop(struct snd_timer * timer)
{
unsigned long flags;
struct snd_pcm_substream *substream;
substream = snd_timer_chip(timer);
spin_lock_irqsave(&substream->timer_lock, flags);
substream->timer_running = 0;
spin_unlock_irqrestore(&substream->timer_lock, flags);
return 0;
}
static struct snd_timer_hardware snd_pcm_timer =
{
.flags = SNDRV_TIMER_HW_AUTO | SNDRV_TIMER_HW_SLAVE,
.resolution = 0,
.ticks = 1,
.c_resolution = snd_pcm_timer_resolution,
.start = snd_pcm_timer_start,
.stop = snd_pcm_timer_stop,
};
/*
* Init functions
*/
static void snd_pcm_timer_free(struct snd_timer *timer)
{
struct snd_pcm_substream *substream = timer->private_data;
substream->timer = NULL;
}
void snd_pcm_timer_init(struct snd_pcm_substream *substream)
{
struct snd_timer_id tid;
struct snd_timer *timer;
tid.dev_sclass = SNDRV_TIMER_SCLASS_NONE;
tid.dev_class = SNDRV_TIMER_CLASS_PCM;
tid.card = substream->pcm->card->number;
tid.device = substream->pcm->device;
tid.subdevice = (substream->number << 1) | (substream->stream & 1);
if (snd_timer_new(substream->pcm->card, "PCM", &tid, &timer) < 0)
return;
sprintf(timer->name, "PCM %s %i-%i-%i",
substream->stream == SNDRV_PCM_STREAM_CAPTURE ?
"capture" : "playback",
tid.card, tid.device, tid.subdevice);
timer->hw = snd_pcm_timer;
if (snd_device_register(timer->card, timer) < 0) {
snd_device_free(timer->card, timer);
return;
}
timer->private_data = substream;
timer->private_free = snd_pcm_timer_free;
substream->timer = timer;
}
void snd_pcm_timer_done(struct snd_pcm_substream *substream)
{
if (substream->timer) {
snd_device_free(substream->pcm->card, substream->timer);
substream->timer = NULL;
}
}
|
