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22#include <linux/time.h>
23#include <sound/core.h>
24#include <sound/pcm.h>
25#include <sound/timer.h>
26
27
28
29
30
31
32static 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
47void 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
78static 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
86static 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
95static 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
104static 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
116
117
118static 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
124void 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
150void 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}
157