2 * Digital Audio (PCM) abstract layer
3 * Copyright (c) by Jaroslav Kysela <perex@suse.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 <sound/driver.h>
23 #include <linux/time.h>
24 #include <sound/core.h>
25 #include <sound/pcm.h>
26 #include <sound/timer.h>
28 #define chip_t snd_pcm_substream_t
34 /* Greatest common divisor */
35 static unsigned long gcd(unsigned long a, unsigned long b)
43 while ((r = a % b) != 0) {
50 void snd_pcm_timer_resolution_change(snd_pcm_substream_t *substream)
52 unsigned long rate, mult, fsize, l;
53 snd_pcm_runtime_t *runtime = substream->runtime;
57 snd_assert(rate != 0, return);
61 fsize = runtime->period_size;
62 snd_assert(fsize != 0, return);
66 while ((mult * fsize) / fsize != mult) {
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;
75 runtime->timer_resolution = mult * fsize / rate;
78 static unsigned long snd_pcm_timer_resolution(snd_timer_t * timer)
80 snd_pcm_substream_t * substream;
82 substream = snd_magic_cast(snd_pcm_substream_t, timer->private_data, return -ENXIO);
83 return substream->runtime ? substream->runtime->timer_resolution : 0;
86 static int snd_pcm_timer_start(snd_timer_t * timer)
89 snd_pcm_substream_t * substream;
91 substream = snd_timer_chip(timer);
92 spin_lock_irqsave(&substream->timer_lock, flags);
93 substream->timer_running = 1;
94 spin_unlock_irqrestore(&substream->timer_lock, flags);
98 static int snd_pcm_timer_stop(snd_timer_t * timer)
101 snd_pcm_substream_t * substream;
103 substream = snd_timer_chip(timer);
104 spin_lock_irqsave(&substream->timer_lock, flags);
105 substream->timer_running = 0;
106 spin_unlock_irqrestore(&substream->timer_lock, flags);
110 static struct _snd_timer_hardware snd_pcm_timer =
112 .flags = SNDRV_TIMER_HW_AUTO | SNDRV_TIMER_HW_SLAVE,
115 .c_resolution = snd_pcm_timer_resolution,
116 .start = snd_pcm_timer_start,
117 .stop = snd_pcm_timer_stop,
124 static void snd_pcm_timer_free(snd_timer_t *timer)
126 snd_pcm_substream_t *substream = snd_magic_cast(snd_pcm_substream_t, timer->private_data, return);
127 substream->timer = NULL;
130 void snd_pcm_timer_init(snd_pcm_substream_t *substream)
135 tid.dev_sclass = SNDRV_TIMER_SCLASS_NONE;
136 tid.dev_class = SNDRV_TIMER_CLASS_PCM;
137 tid.card = substream->pcm->card->number;
138 tid.device = substream->pcm->device;
139 tid.subdevice = (substream->number << 1) | (substream->stream & 1);
140 if (snd_timer_new(substream->pcm->card, "PCM", &tid, &timer) < 0)
142 sprintf(timer->name, "PCM %s %i-%i-%i",
143 substream->stream == SNDRV_PCM_STREAM_CAPTURE ?
144 "capture" : "playback",
145 tid.card, tid.device, tid.subdevice);
146 timer->hw = snd_pcm_timer;
147 if (snd_device_register(timer->card, timer) < 0) {
148 snd_device_free(timer->card, timer);
151 timer->private_data = substream;
152 timer->private_free = snd_pcm_timer_free;
153 substream->timer = timer;
156 void snd_pcm_timer_done(snd_pcm_substream_t *substream)
158 if (substream->timer) {
159 snd_device_free(substream->pcm->card, substream->timer);
160 substream->timer = NULL;