cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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pcm_timer.c (3085B)

      1// SPDX-License-Identifier: GPL-2.0-or-later
      2/*
      3 *  Digital Audio (PCM) abstract layer
      4 *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
      5 */
      6
      7#include <linux/time.h>
      8#include <linux/gcd.h>
      9#include <sound/core.h>
     10#include <sound/pcm.h>
     11#include <sound/timer.h>
     12
     13#include "pcm_local.h"
     14
     15/*
     16 *  Timer functions
     17 */
     18
     19void snd_pcm_timer_resolution_change(struct snd_pcm_substream *substream)
     20{
     21	unsigned long rate, mult, fsize, l, post;
     22	struct snd_pcm_runtime *runtime = substream->runtime;
     23
     24	mult = 1000000000;
     25	rate = runtime->rate;
     26	if (snd_BUG_ON(!rate))
     27		return;
     28	l = gcd(mult, rate);
     29	mult /= l;
     30	rate /= l;
     31	fsize = runtime->period_size;
     32	if (snd_BUG_ON(!fsize))
     33		return;
     34	l = gcd(rate, fsize);
     35	rate /= l;
     36	fsize /= l;
     37	post = 1;
     38	while ((mult * fsize) / fsize != mult) {
     39		mult /= 2;
     40		post *= 2;
     41	}
     42	if (rate == 0) {
     43		pcm_err(substream->pcm,
     44			"pcm timer resolution out of range (rate = %u, period_size = %lu)\n",
     45			runtime->rate, runtime->period_size);
     46		runtime->timer_resolution = -1;
     47		return;
     48	}
     49	runtime->timer_resolution = (mult * fsize / rate) * post;
     50}
     51
     52static unsigned long snd_pcm_timer_resolution(struct snd_timer * timer)
     53{
     54	struct snd_pcm_substream *substream;
     55
     56	substream = timer->private_data;
     57	return substream->runtime ? substream->runtime->timer_resolution : 0;
     58}
     59
     60static int snd_pcm_timer_start(struct snd_timer * timer)
     61{
     62	struct snd_pcm_substream *substream;
     63
     64	substream = snd_timer_chip(timer);
     65	substream->timer_running = 1;
     66	return 0;
     67}
     68
     69static int snd_pcm_timer_stop(struct snd_timer * timer)
     70{
     71	struct snd_pcm_substream *substream;
     72
     73	substream = snd_timer_chip(timer);
     74	substream->timer_running = 0;
     75	return 0;
     76}
     77
     78static const struct snd_timer_hardware snd_pcm_timer =
     79{
     80	.flags =	SNDRV_TIMER_HW_AUTO | SNDRV_TIMER_HW_SLAVE,
     81	.resolution =	0,
     82	.ticks =	1,
     83	.c_resolution =	snd_pcm_timer_resolution,
     84	.start =	snd_pcm_timer_start,
     85	.stop =		snd_pcm_timer_stop,
     86};
     87
     88/*
     89 *  Init functions
     90 */
     91
     92static void snd_pcm_timer_free(struct snd_timer *timer)
     93{
     94	struct snd_pcm_substream *substream = timer->private_data;
     95	substream->timer = NULL;
     96}
     97
     98void snd_pcm_timer_init(struct snd_pcm_substream *substream)
     99{
    100	struct snd_timer_id tid;
    101	struct snd_timer *timer;
    102
    103	tid.dev_sclass = SNDRV_TIMER_SCLASS_NONE;
    104	tid.dev_class = SNDRV_TIMER_CLASS_PCM;
    105	tid.card = substream->pcm->card->number;
    106	tid.device = substream->pcm->device;
    107	tid.subdevice = (substream->number << 1) | (substream->stream & 1);
    108	if (snd_timer_new(substream->pcm->card, "PCM", &tid, &timer) < 0)
    109		return;
    110	sprintf(timer->name, "PCM %s %i-%i-%i",
    111			substream->stream == SNDRV_PCM_STREAM_CAPTURE ?
    112				"capture" : "playback",
    113			tid.card, tid.device, tid.subdevice);
    114	timer->hw = snd_pcm_timer;
    115	if (snd_device_register(timer->card, timer) < 0) {
    116		snd_device_free(timer->card, timer);
    117		return;
    118	}
    119	timer->private_data = substream;
    120	timer->private_free = snd_pcm_timer_free;
    121	substream->timer = timer;
    122}
    123
    124void snd_pcm_timer_done(struct snd_pcm_substream *substream)
    125{
    126	if (substream->timer) {
    127		snd_device_free(substream->pcm->card, substream->timer);
    128		substream->timer = NULL;
    129	}
    130}