d94ed16d21ea9dac3e93d776b116f8c25b8def6c
[linux-2.6.git] / sound / core / pcm_timer.c
1 /*
2  *  Digital Audio (PCM) abstract layer
3  *  Copyright (c) by Jaroslav Kysela <perex@suse.cz>
4  *
5  *
6  *   This program is free software; you can redistribute it and/or modify
7  *   it under the terms of the GNU General Public License as published by
8  *   the Free Software Foundation; either version 2 of the License, or
9  *   (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 General Public License for more details.
15  *
16  *   You should have received a copy of the GNU General Public License
17  *   along with this program; 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 <sound/driver.h>
23 #include <linux/time.h>
24 #include <sound/core.h>
25 #include <sound/pcm.h>
26 #include <sound/timer.h>
27
28 /*
29  *  Timer functions
30  */
31
32 /* Greatest common divisor */
33 static unsigned long gcd(unsigned long a, unsigned long b)
34 {
35         unsigned long r;
36         if (a < b) {
37                 r = a;
38                 a = b;
39                 b = r;
40         }
41         while ((r = a % b) != 0) {
42                 a = b;
43                 b = r;
44         }
45         return b;
46 }
47
48 void snd_pcm_timer_resolution_change(struct snd_pcm_substream *substream)
49 {
50         unsigned long rate, mult, fsize, l, post;
51         struct snd_pcm_runtime *runtime = substream->runtime;
52         
53         mult = 1000000000;
54         rate = runtime->rate;
55         snd_assert(rate != 0, return);
56         l = gcd(mult, rate);
57         mult /= l;
58         rate /= l;
59         fsize = runtime->period_size;
60         snd_assert(fsize != 0, return);
61         l = gcd(rate, fsize);
62         rate /= l;
63         fsize /= l;
64         post = 1;
65         while ((mult * fsize) / fsize != mult) {
66                 mult /= 2;
67                 post *= 2;
68         }
69         if (rate == 0) {
70                 snd_printk(KERN_ERR "pcm timer resolution out of range (rate = %u, period_size = %lu)\n", runtime->rate, runtime->period_size);
71                 runtime->timer_resolution = -1;
72                 return;
73         }
74         runtime->timer_resolution = (mult * fsize / rate) * post;
75 }
76
77 static unsigned long snd_pcm_timer_resolution(struct snd_timer * timer)
78 {
79         struct snd_pcm_substream *substream;
80         
81         substream = timer->private_data;
82         return substream->runtime ? substream->runtime->timer_resolution : 0;
83 }
84
85 static int snd_pcm_timer_start(struct snd_timer * timer)
86 {
87         unsigned long flags;
88         struct snd_pcm_substream *substream;
89         
90         substream = snd_timer_chip(timer);
91         spin_lock_irqsave(&substream->timer_lock, flags);
92         substream->timer_running = 1;
93         spin_unlock_irqrestore(&substream->timer_lock, flags);
94         return 0;
95 }
96
97 static int snd_pcm_timer_stop(struct snd_timer * timer)
98 {
99         unsigned long flags;
100         struct snd_pcm_substream *substream;
101         
102         substream = snd_timer_chip(timer);
103         spin_lock_irqsave(&substream->timer_lock, flags);
104         substream->timer_running = 0;
105         spin_unlock_irqrestore(&substream->timer_lock, flags);
106         return 0;
107 }
108
109 static struct snd_timer_hardware snd_pcm_timer =
110 {
111         .flags =        SNDRV_TIMER_HW_AUTO | SNDRV_TIMER_HW_SLAVE,
112         .resolution =   0,
113         .ticks =        1,
114         .c_resolution = snd_pcm_timer_resolution,
115         .start =        snd_pcm_timer_start,
116         .stop =         snd_pcm_timer_stop,
117 };
118
119 /*
120  *  Init functions
121  */
122
123 static void snd_pcm_timer_free(struct snd_timer *timer)
124 {
125         struct snd_pcm_substream *substream = timer->private_data;
126         substream->timer = NULL;
127 }
128
129 void snd_pcm_timer_init(struct snd_pcm_substream *substream)
130 {
131         struct snd_timer_id tid;
132         struct snd_timer *timer;
133         
134         tid.dev_sclass = SNDRV_TIMER_SCLASS_NONE;
135         tid.dev_class = SNDRV_TIMER_CLASS_PCM;
136         tid.card = substream->pcm->card->number;
137         tid.device = substream->pcm->device;
138         tid.subdevice = (substream->number << 1) | (substream->stream & 1);
139         if (snd_timer_new(substream->pcm->card, "PCM", &tid, &timer) < 0)
140                 return;
141         sprintf(timer->name, "PCM %s %i-%i-%i",
142                         substream->stream == SNDRV_PCM_STREAM_CAPTURE ?
143                                 "capture" : "playback",
144                         tid.card, tid.device, tid.subdevice);
145         timer->hw = snd_pcm_timer;
146         if (snd_device_register(timer->card, timer) < 0) {
147                 snd_device_free(timer->card, timer);
148                 return;
149         }
150         timer->private_data = substream;
151         timer->private_free = snd_pcm_timer_free;
152         substream->timer = timer;
153 }
154
155 void snd_pcm_timer_done(struct snd_pcm_substream *substream)
156 {
157         if (substream->timer) {
158                 snd_device_free(substream->pcm->card, substream->timer);
159                 substream->timer = NULL;
160         }
161 }