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