2 * Digital Audio (PCM) abstract layer
3 * Copyright (c) by Jaroslav Kysela <perex@perex.cz>
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.
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.
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
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>
32 void snd_pcm_timer_resolution_change(struct snd_pcm_substream
*substream
)
34 unsigned long rate
, mult
, fsize
, l
, post
;
35 struct snd_pcm_runtime
*runtime
= substream
->runtime
;
39 if (snd_BUG_ON(!rate
))
44 fsize
= runtime
->period_size
;
45 if (snd_BUG_ON(!fsize
))
51 while ((mult
* fsize
) / fsize
!= mult
) {
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;
60 runtime
->timer_resolution
= (mult
* fsize
/ rate
) * post
;
63 static unsigned long snd_pcm_timer_resolution(struct snd_timer
* timer
)
65 struct snd_pcm_substream
*substream
;
67 substream
= timer
->private_data
;
68 return substream
->runtime
? substream
->runtime
->timer_resolution
: 0;
71 static int snd_pcm_timer_start(struct snd_timer
* timer
)
73 struct snd_pcm_substream
*substream
;
75 substream
= snd_timer_chip(timer
);
76 substream
->timer_running
= 1;
80 static int snd_pcm_timer_stop(struct snd_timer
* timer
)
82 struct snd_pcm_substream
*substream
;
84 substream
= snd_timer_chip(timer
);
85 substream
->timer_running
= 0;
89 static struct snd_timer_hardware snd_pcm_timer
=
91 .flags
= SNDRV_TIMER_HW_AUTO
| SNDRV_TIMER_HW_SLAVE
,
94 .c_resolution
= snd_pcm_timer_resolution
,
95 .start
= snd_pcm_timer_start
,
96 .stop
= snd_pcm_timer_stop
,
103 static void snd_pcm_timer_free(struct snd_timer
*timer
)
105 struct snd_pcm_substream
*substream
= timer
->private_data
;
106 substream
->timer
= NULL
;
109 void snd_pcm_timer_init(struct snd_pcm_substream
*substream
)
111 struct snd_timer_id tid
;
112 struct snd_timer
*timer
;
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)
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
);
130 timer
->private_data
= substream
;
131 timer
->private_free
= snd_pcm_timer_free
;
132 substream
->timer
= timer
;
135 void snd_pcm_timer_done(struct snd_pcm_substream
*substream
)
137 if (substream
->timer
) {
138 snd_device_free(substream
->pcm
->card
, substream
->timer
);
139 substream
->timer
= NULL
;