Merge branch 'master' of /home/davem/src/GIT/linux-2.6/
[linux-2.6] / sound / core / pcm_timer.c
1 /*
2  *  Digital Audio (PCM) abstract layer
3  *  Copyright (c) by Jaroslav Kysela <perex@perex.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 <linux/time.h>
23 #include <sound/core.h>
24 #include <sound/pcm.h>
25 #include <sound/timer.h>
26
27 /*
28  *  Timer functions
29  */
30
31 /* Greatest common divisor */
32 static unsigned long gcd(unsigned long a, unsigned long b)
33 {
34         unsigned long r;
35         if (a < b) {
36                 r = a;
37                 a = b;
38                 b = r;
39         }
40         while ((r = a % b) != 0) {
41                 a = b;
42                 b = r;
43         }
44         return b;
45 }
46
47 void snd_pcm_timer_resolution_change(struct snd_pcm_substream *substream)
48 {
49         unsigned long rate, mult, fsize, l, post;
50         struct snd_pcm_runtime *runtime = substream->runtime;
51         
52         mult = 1000000000;
53         rate = runtime->rate;
54         if (snd_BUG_ON(!rate))
55                 return;
56         l = gcd(mult, rate);
57         mult /= l;
58         rate /= l;
59         fsize = runtime->period_size;
60         if (snd_BUG_ON(!fsize))
61                 return;
62         l = gcd(rate, fsize);
63         rate /= l;
64         fsize /= l;
65         post = 1;
66         while ((mult * fsize) / fsize != mult) {
67                 mult /= 2;
68                 post *= 2;
69         }
70         if (rate == 0) {
71                 snd_printk(KERN_ERR "pcm timer resolution out of range (rate = %u, period_size = %lu)\n", runtime->rate, runtime->period_size);
72                 runtime->timer_resolution = -1;
73                 return;
74         }
75         runtime->timer_resolution = (mult * fsize / rate) * post;
76 }
77
78 static unsigned long snd_pcm_timer_resolution(struct snd_timer * timer)
79 {
80         struct snd_pcm_substream *substream;
81         
82         substream = timer->private_data;
83         return substream->runtime ? substream->runtime->timer_resolution : 0;
84 }
85
86 static int snd_pcm_timer_start(struct snd_timer * timer)
87 {
88         struct snd_pcm_substream *substream;
89         
90         substream = snd_timer_chip(timer);
91         substream->timer_running = 1;
92         return 0;
93 }
94
95 static int snd_pcm_timer_stop(struct snd_timer * timer)
96 {
97         struct snd_pcm_substream *substream;
98         
99         substream = snd_timer_chip(timer);
100         substream->timer_running = 0;
101         return 0;
102 }
103
104 static struct snd_timer_hardware snd_pcm_timer =
105 {
106         .flags =        SNDRV_TIMER_HW_AUTO | SNDRV_TIMER_HW_SLAVE,
107         .resolution =   0,
108         .ticks =        1,
109         .c_resolution = snd_pcm_timer_resolution,
110         .start =        snd_pcm_timer_start,
111         .stop =         snd_pcm_timer_stop,
112 };
113
114 /*
115  *  Init functions
116  */
117
118 static void snd_pcm_timer_free(struct snd_timer *timer)
119 {
120         struct snd_pcm_substream *substream = timer->private_data;
121         substream->timer = NULL;
122 }
123
124 void snd_pcm_timer_init(struct snd_pcm_substream *substream)
125 {
126         struct snd_timer_id tid;
127         struct snd_timer *timer;
128         
129         tid.dev_sclass = SNDRV_TIMER_SCLASS_NONE;
130         tid.dev_class = SNDRV_TIMER_CLASS_PCM;
131         tid.card = substream->pcm->card->number;
132         tid.device = substream->pcm->device;
133         tid.subdevice = (substream->number << 1) | (substream->stream & 1);
134         if (snd_timer_new(substream->pcm->card, "PCM", &tid, &timer) < 0)
135                 return;
136         sprintf(timer->name, "PCM %s %i-%i-%i",
137                         substream->stream == SNDRV_PCM_STREAM_CAPTURE ?
138                                 "capture" : "playback",
139                         tid.card, tid.device, tid.subdevice);
140         timer->hw = snd_pcm_timer;
141         if (snd_device_register(timer->card, timer) < 0) {
142                 snd_device_free(timer->card, timer);
143                 return;
144         }
145         timer->private_data = substream;
146         timer->private_free = snd_pcm_timer_free;
147         substream->timer = timer;
148 }
149
150 void snd_pcm_timer_done(struct snd_pcm_substream *substream)
151 {
152         if (substream->timer) {
153                 snd_device_free(substream->pcm->card, substream->timer);
154                 substream->timer = NULL;
155         }
156 }