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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 | snd_printk(KERN_ERR "pcm timer resolution out of range (rate = %u, period_size = %lu)\n", runtime->rate, runtime->period_size); |
57 | runtime->timer_resolution = -1; |
58 | return; |
59 | } |
60 | runtime->timer_resolution = (mult * fsize / rate) * post; |
61 | } |
62 | |
63 | static unsigned long snd_pcm_timer_resolution(struct snd_timer * timer) |
64 | { |
65 | struct snd_pcm_substream *substream; |
66 | |
67 | substream = timer->private_data; |
68 | return substream->runtime ? substream->runtime->timer_resolution : 0; |
69 | } |
70 | |
71 | static int snd_pcm_timer_start(struct snd_timer * timer) |
72 | { |
73 | struct snd_pcm_substream *substream; |
74 | |
75 | substream = snd_timer_chip(timer); |
76 | substream->timer_running = 1; |
77 | return 0; |
78 | } |
79 | |
80 | static int snd_pcm_timer_stop(struct snd_timer * timer) |
81 | { |
82 | struct snd_pcm_substream *substream; |
83 | |
84 | substream = snd_timer_chip(timer); |
85 | substream->timer_running = 0; |
86 | return 0; |
87 | } |
88 | |
89 | static struct snd_timer_hardware snd_pcm_timer = |
90 | { |
91 | .flags = SNDRV_TIMER_HW_AUTO | SNDRV_TIMER_HW_SLAVE, |
92 | .resolution = 0, |
93 | .ticks = 1, |
94 | .c_resolution = snd_pcm_timer_resolution, |
95 | .start = snd_pcm_timer_start, |
96 | .stop = snd_pcm_timer_stop, |
97 | }; |
98 | |
99 | /* |
100 | * Init functions |
101 | */ |
102 | |
103 | static void snd_pcm_timer_free(struct snd_timer *timer) |
104 | { |
105 | struct snd_pcm_substream *substream = timer->private_data; |
106 | substream->timer = NULL; |
107 | } |
108 | |
109 | void snd_pcm_timer_init(struct snd_pcm_substream *substream) |
110 | { |
111 | struct snd_timer_id tid; |
112 | struct snd_timer *timer; |
113 | |
114 | tid.dev_sclass = SNDRV_TIMER_SCLASS_NONE; |
115 | tid.dev_class = SNDRV_TIMER_CLASS_PCM; |
116 | tid.card = substream->pcm->card->number; |
117 | tid.device = substream->pcm->device; |
118 | tid.subdevice = (substream->number << 1) | (substream->stream & 1); |
119 | if (snd_timer_new(substream->pcm->card, "PCM", &tid, &timer) < 0) |
120 | return; |
121 | sprintf(timer->name, "PCM %s %i-%i-%i", |
122 | substream->stream == SNDRV_PCM_STREAM_CAPTURE ? |
123 | "capture" : "playback", |
124 | tid.card, tid.device, tid.subdevice); |
125 | timer->hw = snd_pcm_timer; |
126 | if (snd_device_register(timer->card, timer) < 0) { |
127 | snd_device_free(timer->card, timer); |
128 | return; |
129 | } |
130 | timer->private_data = substream; |
131 | timer->private_free = snd_pcm_timer_free; |
132 | substream->timer = timer; |
133 | } |
134 | |
135 | void snd_pcm_timer_done(struct snd_pcm_substream *substream) |
136 | { |
137 | if (substream->timer) { |
138 | snd_device_free(substream->pcm->card, substream->timer); |
139 | substream->timer = NULL; |
140 | } |
141 | } |
142 |
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Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
v2.6.34-rc6
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v3.9