// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  Digital Audio (PCM) abstract layer
 *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
 */

#include <linux/time.h>
#include <linux/gcd.h>
#include <sound/core.h>
#include <sound/pcm.h>
#include <sound/timer.h>

#include "pcm_local.h"

/*
 *  Timer functions
 */

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) {
                pcm_err(substream->pcm,
                        "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 const 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",
                        snd_pcm_direction_name(substream->stream),
                        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;
        }
}