85122ea40c
The timer callbacks are called in the protected status by the lock of the timer instance, so there is no need for an extra lock in the PCM substream. Signed-off-by: Takashi Iwai <tiwai@suse.de>
156 lines
3.9 KiB
C
156 lines
3.9 KiB
C
/*
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* Digital Audio (PCM) abstract layer
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* Copyright (c) by Jaroslav Kysela <perex@perex.cz>
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*
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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*/
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#include <linux/time.h>
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#include <sound/core.h>
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#include <sound/pcm.h>
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#include <sound/timer.h>
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/*
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* Timer functions
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*/
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/* Greatest common divisor */
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static unsigned long gcd(unsigned long a, unsigned long b)
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{
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unsigned long r;
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if (a < b) {
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r = a;
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a = b;
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b = r;
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}
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while ((r = a % b) != 0) {
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a = b;
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b = r;
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}
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return b;
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}
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void snd_pcm_timer_resolution_change(struct snd_pcm_substream *substream)
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{
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unsigned long rate, mult, fsize, l, post;
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struct snd_pcm_runtime *runtime = substream->runtime;
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mult = 1000000000;
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rate = runtime->rate;
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if (snd_BUG_ON(!rate))
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return;
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l = gcd(mult, rate);
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mult /= l;
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rate /= l;
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fsize = runtime->period_size;
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if (snd_BUG_ON(!fsize))
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return;
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l = gcd(rate, fsize);
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rate /= l;
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fsize /= l;
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post = 1;
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while ((mult * fsize) / fsize != mult) {
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mult /= 2;
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post *= 2;
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}
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if (rate == 0) {
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snd_printk(KERN_ERR "pcm timer resolution out of range (rate = %u, period_size = %lu)\n", runtime->rate, runtime->period_size);
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runtime->timer_resolution = -1;
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return;
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}
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runtime->timer_resolution = (mult * fsize / rate) * post;
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}
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static unsigned long snd_pcm_timer_resolution(struct snd_timer * timer)
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{
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struct snd_pcm_substream *substream;
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substream = timer->private_data;
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return substream->runtime ? substream->runtime->timer_resolution : 0;
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}
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static int snd_pcm_timer_start(struct snd_timer * timer)
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{
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struct snd_pcm_substream *substream;
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substream = snd_timer_chip(timer);
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substream->timer_running = 1;
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return 0;
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}
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static int snd_pcm_timer_stop(struct snd_timer * timer)
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{
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struct snd_pcm_substream *substream;
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substream = snd_timer_chip(timer);
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substream->timer_running = 0;
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return 0;
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}
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static struct snd_timer_hardware snd_pcm_timer =
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{
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.flags = SNDRV_TIMER_HW_AUTO | SNDRV_TIMER_HW_SLAVE,
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.resolution = 0,
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.ticks = 1,
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.c_resolution = snd_pcm_timer_resolution,
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.start = snd_pcm_timer_start,
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.stop = snd_pcm_timer_stop,
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};
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/*
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* Init functions
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*/
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static void snd_pcm_timer_free(struct snd_timer *timer)
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{
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struct snd_pcm_substream *substream = timer->private_data;
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substream->timer = NULL;
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}
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void snd_pcm_timer_init(struct snd_pcm_substream *substream)
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{
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struct snd_timer_id tid;
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struct snd_timer *timer;
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tid.dev_sclass = SNDRV_TIMER_SCLASS_NONE;
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tid.dev_class = SNDRV_TIMER_CLASS_PCM;
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tid.card = substream->pcm->card->number;
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tid.device = substream->pcm->device;
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tid.subdevice = (substream->number << 1) | (substream->stream & 1);
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if (snd_timer_new(substream->pcm->card, "PCM", &tid, &timer) < 0)
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return;
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sprintf(timer->name, "PCM %s %i-%i-%i",
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substream->stream == SNDRV_PCM_STREAM_CAPTURE ?
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"capture" : "playback",
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tid.card, tid.device, tid.subdevice);
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timer->hw = snd_pcm_timer;
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if (snd_device_register(timer->card, timer) < 0) {
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snd_device_free(timer->card, timer);
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return;
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}
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timer->private_data = substream;
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timer->private_free = snd_pcm_timer_free;
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substream->timer = timer;
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}
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void snd_pcm_timer_done(struct snd_pcm_substream *substream)
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{
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if (substream->timer) {
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snd_device_free(substream->pcm->card, substream->timer);
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substream->timer = NULL;
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}
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}
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