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130 lines
3.0 KiB
130 lines
3.0 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* Digital Audio (PCM) abstract layer |
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* Copyright (c) by Jaroslav Kysela <[email protected]> |
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*/ |
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#include <linux/time.h> |
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#include <linux/gcd.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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#include "pcm_local.h" |
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/* |
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* Timer functions |
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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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pcm_err(substream->pcm, |
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"pcm timer resolution out of range (rate = %u, period_size = %lu)\n", |
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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 const 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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