Merge branch 'for-2.6.25' of git://git.secretlab.ca/git/linux-2.6-mpc52xx into for...
[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         snd_assert(rate != 0, return);
55         l = gcd(mult, rate);
56         mult /= l;
57         rate /= l;
58         fsize = runtime->period_size;
59         snd_assert(fsize != 0, return);
60         l = gcd(rate, fsize);
61         rate /= l;
62         fsize /= l;
63         post = 1;
64         while ((mult * fsize) / fsize != mult) {
65                 mult /= 2;
66                 post *= 2;
67         }
68         if (rate == 0) {
69                 snd_printk(KERN_ERR "pcm timer resolution out of range (rate = %u, period_size = %lu)\n", runtime->rate, runtime->period_size);
70                 runtime->timer_resolution = -1;
71                 return;
72         }
73         runtime->timer_resolution = (mult * fsize / rate) * post;
74 }
75
76 static unsigned long snd_pcm_timer_resolution(struct snd_timer * timer)
77 {
78         struct snd_pcm_substream *substream;
79         
80         substream = timer->private_data;
81         return substream->runtime ? substream->runtime->timer_resolution : 0;
82 }
83
84 static int snd_pcm_timer_start(struct snd_timer * timer)
85 {
86         unsigned long flags;
87         struct snd_pcm_substream *substream;
88         
89         substream = snd_timer_chip(timer);
90         spin_lock_irqsave(&substream->timer_lock, flags);
91         substream->timer_running = 1;
92         spin_unlock_irqrestore(&substream->timer_lock, flags);
93         return 0;
94 }
95
96 static int snd_pcm_timer_stop(struct snd_timer * timer)
97 {
98         unsigned long flags;
99         struct snd_pcm_substream *substream;
100         
101         substream = snd_timer_chip(timer);
102         spin_lock_irqsave(&substream->timer_lock, flags);
103         substream->timer_running = 0;
104         spin_unlock_irqrestore(&substream->timer_lock, flags);
105         return 0;
106 }
107
108 static struct snd_timer_hardware snd_pcm_timer =
109 {
110         .flags =        SNDRV_TIMER_HW_AUTO | SNDRV_TIMER_HW_SLAVE,
111         .resolution =   0,
112         .ticks =        1,
113         .c_resolution = snd_pcm_timer_resolution,
114         .start =        snd_pcm_timer_start,
115         .stop =         snd_pcm_timer_stop,
116 };
117
118 /*
119  *  Init functions
120  */
121
122 static void snd_pcm_timer_free(struct snd_timer *timer)
123 {
124         struct snd_pcm_substream *substream = timer->private_data;
125         substream->timer = NULL;
126 }
127
128 void snd_pcm_timer_init(struct snd_pcm_substream *substream)
129 {
130         struct snd_timer_id tid;
131         struct snd_timer *timer;
132         
133         tid.dev_sclass = SNDRV_TIMER_SCLASS_NONE;
134         tid.dev_class = SNDRV_TIMER_CLASS_PCM;
135         tid.card = substream->pcm->card->number;
136         tid.device = substream->pcm->device;
137         tid.subdevice = (substream->number << 1) | (substream->stream & 1);
138         if (snd_timer_new(substream->pcm->card, "PCM", &tid, &timer) < 0)
139                 return;
140         sprintf(timer->name, "PCM %s %i-%i-%i",
141                         substream->stream == SNDRV_PCM_STREAM_CAPTURE ?
142                                 "capture" : "playback",
143                         tid.card, tid.device, tid.subdevice);
144         timer->hw = snd_pcm_timer;
145         if (snd_device_register(timer->card, timer) < 0) {
146                 snd_device_free(timer->card, timer);
147                 return;
148         }
149         timer->private_data = substream;
150         timer->private_free = snd_pcm_timer_free;
151         substream->timer = timer;
152 }
153
154 void snd_pcm_timer_done(struct snd_pcm_substream *substream)
155 {
156         if (substream->timer) {
157                 snd_device_free(substream->pcm->card, substream->timer);
158                 substream->timer = NULL;
159         }
160 }