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/*
* Digital Audio (PCM) abstract layer
* Copyright (c) by Jaroslav Kysela <perex@perex.cz>
*
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*/
#include <linux/time.h>
#include <sound/core.h>
#include <sound/pcm.h>
#include <sound/timer.h>
/*
* Timer functions
*/
/* Greatest common divisor */
static unsigned long gcd(unsigned long a, unsigned long b)
{
unsigned long r;
if (a < b) {
r = a;
a = b;
b = r;
}
while ((r = a % b) != 0) {
a = b;
b = r;
}
return b;
}
void snd_pcm_timer_resolution_change(struct snd_pcm_substream *substream)
{
unsigned long rate, mult, fsize, l, post;
struct snd_pcm_runtime *runtime = substream->runtime;
mult = 1000000000;
rate = runtime->rate;
if (snd_BUG_ON(!rate))
return;
l = gcd(mult, rate);
mult /= l;
rate /= l;
fsize = runtime->period_size;
if (snd_BUG_ON(!fsize))
return;
l = gcd(rate, fsize);
rate /= l;
fsize /= l;
post = 1;
while ((mult * fsize) / fsize != mult) {
mult /= 2;
post *= 2;
}
if (rate == 0) {
snd_printk(KERN_ERR "pcm timer resolution out of range (rate = %u, period_size = %lu)\n", runtime->rate, runtime->period_size);
runtime->timer_resolution = -1;
return;
}
runtime->timer_resolution = (mult * fsize / rate) * post;
}
static unsigned long snd_pcm_timer_resolution(struct snd_timer * timer)
{
struct snd_pcm_substream *substream;
substream = timer->private_data;
return substream->runtime ? substream->runtime->timer_resolution : 0;
}
static int snd_pcm_timer_start(struct snd_timer * timer)
{
struct snd_pcm_substream *substream;
substream = snd_timer_chip(timer);
substream->timer_running = 1;
return 0;
}
static int snd_pcm_timer_stop(struct snd_timer * timer)
{
struct snd_pcm_substream *substream;
substream = snd_timer_chip(timer);
substream->timer_running = 0;
return 0;
}
static struct snd_timer_hardware snd_pcm_timer =
{
.flags = SNDRV_TIMER_HW_AUTO | SNDRV_TIMER_HW_SLAVE,
.resolution = 0,
.ticks = 1,
.c_resolution = snd_pcm_timer_resolution,
.start = snd_pcm_timer_start,
.stop = snd_pcm_timer_stop,
};
/*
* Init functions
*/
static void snd_pcm_timer_free(struct snd_timer *timer)
{
struct snd_pcm_substream *substream = timer->private_data;
substream->timer = NULL;
}
void snd_pcm_timer_init(struct snd_pcm_substream *substream)
{
struct snd_timer_id tid;
struct snd_timer *timer;
tid.dev_sclass = SNDRV_TIMER_SCLASS_NONE;
tid.dev_class = SNDRV_TIMER_CLASS_PCM;
tid.card = substream->pcm->card->number;
tid.device = substream->pcm->device;
tid.subdevice = (substream->number << 1) | (substream->stream & 1);
if (snd_timer_new(substream->pcm->card, "PCM", &tid, &timer) < 0)
return;
sprintf(timer->name, "PCM %s %i-%i-%i",
substream->stream == SNDRV_PCM_STREAM_CAPTURE ?
"capture" : "playback",
tid.card, tid.device, tid.subdevice);
timer->hw = snd_pcm_timer;
if (snd_device_register(timer->card, timer) < 0) {
snd_device_free(timer->card, timer);
return;
}
timer->private_data = substream;
timer->private_free = snd_pcm_timer_free;
substream->timer = timer;
}
void snd_pcm_timer_done(struct snd_pcm_substream *substream)
{
if (substream->timer) {
snd_device_free(substream->pcm->card, substream->timer);
substream->timer = NULL;
}
}
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