Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * Digital Audio (PCM) abstract layer | |
c1017a4c | 3 | * Copyright (c) by Jaroslav Kysela <perex@perex.cz> |
1da177e4 LT |
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 | ||
1da177e4 LT |
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 | ||
877211f5 | 47 | void snd_pcm_timer_resolution_change(struct snd_pcm_substream *substream) |
1da177e4 LT |
48 | { |
49 | unsigned long rate, mult, fsize, l, post; | |
877211f5 | 50 | struct snd_pcm_runtime *runtime = substream->runtime; |
1da177e4 LT |
51 | |
52 | mult = 1000000000; | |
53 | rate = runtime->rate; | |
7eaa943c TI |
54 | if (snd_BUG_ON(!rate)) |
55 | return; | |
1da177e4 LT |
56 | l = gcd(mult, rate); |
57 | mult /= l; | |
58 | rate /= l; | |
59 | fsize = runtime->period_size; | |
7eaa943c TI |
60 | if (snd_BUG_ON(!fsize)) |
61 | return; | |
1da177e4 LT |
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 | ||
877211f5 | 78 | static unsigned long snd_pcm_timer_resolution(struct snd_timer * timer) |
1da177e4 | 79 | { |
877211f5 | 80 | struct snd_pcm_substream *substream; |
1da177e4 LT |
81 | |
82 | substream = timer->private_data; | |
83 | return substream->runtime ? substream->runtime->timer_resolution : 0; | |
84 | } | |
85 | ||
877211f5 | 86 | static int snd_pcm_timer_start(struct snd_timer * timer) |
1da177e4 | 87 | { |
877211f5 | 88 | struct snd_pcm_substream *substream; |
1da177e4 LT |
89 | |
90 | substream = snd_timer_chip(timer); | |
1da177e4 | 91 | substream->timer_running = 1; |
1da177e4 LT |
92 | return 0; |
93 | } | |
94 | ||
877211f5 | 95 | static int snd_pcm_timer_stop(struct snd_timer * timer) |
1da177e4 | 96 | { |
877211f5 | 97 | struct snd_pcm_substream *substream; |
1da177e4 LT |
98 | |
99 | substream = snd_timer_chip(timer); | |
1da177e4 | 100 | substream->timer_running = 0; |
1da177e4 LT |
101 | return 0; |
102 | } | |
103 | ||
877211f5 | 104 | static struct snd_timer_hardware snd_pcm_timer = |
1da177e4 LT |
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 | ||
877211f5 | 118 | static void snd_pcm_timer_free(struct snd_timer *timer) |
1da177e4 | 119 | { |
877211f5 | 120 | struct snd_pcm_substream *substream = timer->private_data; |
1da177e4 LT |
121 | substream->timer = NULL; |
122 | } | |
123 | ||
877211f5 | 124 | void snd_pcm_timer_init(struct snd_pcm_substream *substream) |
1da177e4 | 125 | { |
877211f5 TI |
126 | struct snd_timer_id tid; |
127 | struct snd_timer *timer; | |
1da177e4 LT |
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 | ||
877211f5 | 150 | void snd_pcm_timer_done(struct snd_pcm_substream *substream) |
1da177e4 LT |
151 | { |
152 | if (substream->timer) { | |
153 | snd_device_free(substream->pcm->card, substream->timer); | |
154 | substream->timer = NULL; | |
155 | } | |
156 | } |