/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2024-2025 The FreeBSD Foundation
 *
 * This software was developed by Christos Margiolis <christos@FreeBSD.org>
 * under sponsorship from the FreeBSD Foundation.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/cdefs.h>

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/bus.h>

#ifdef HAVE_KERNEL_OPTION_HEADERS
#include "opt_snd.h"
#endif

#include <dev/sound/pcm/sound.h>
#include <dev/sound/midi/mpu401.h>

#include <mixer_if.h>
#include <mpufoi_if.h>

#define DUMMY_NPCHAN    1
#define DUMMY_NRCHAN    1
#define DUMMY_NCHAN     (DUMMY_NPCHAN + DUMMY_NRCHAN)

struct dummy_chan {
        struct dummy_softc *sc;
        struct pcm_channel *chan;
        struct snd_dbuf *buf;
        struct pcmchan_caps *caps;
        uint32_t ptr;
        int dir;
        int run;
};

struct dummy_softc {
        struct snddev_info info;
        device_t dev;
        uint32_t cap_fmts[4];
        struct pcmchan_caps caps;
        int chnum;
        struct dummy_chan chans[DUMMY_NCHAN];
        struct callout callout;
        struct mtx lock;
        bool stopped;
        struct mpu401 *mpu;
        mpu401_intr_t *mpu_intr;
};

static bool
dummy_active(struct dummy_softc *sc)
{
        struct dummy_chan *ch;
        int i;

        mtx_assert(&sc->lock, MA_OWNED);

        for (i = 0; i < sc->chnum; i++) {
                ch = &sc->chans[i];
                if (ch->run)
                        return (true);
        }

        /* No channel is running at the moment. */
        return (false);
}

static void
dummy_chan_io(void *arg)
{
        struct dummy_softc *sc = arg;
        struct dummy_chan *ch;
        int i = 0;

        if (sc->mpu_intr)
                (sc->mpu_intr)(sc->mpu);

        if (sc->stopped)
                return;

        /* Do not reschedule if no channel is running. */
        if (!dummy_active(sc))
                return;

        for (i = 0; i < sc->chnum; i++) {
                ch = &sc->chans[i];
                if (!ch->run)
                        continue;
                if (ch->dir == PCMDIR_PLAY) {
                        ch->ptr += ch->buf->blksz;
                        ch->ptr %= ch->buf->bufsize;
                } else
                        sndbuf_fillsilence(ch->buf);
                mtx_unlock(&sc->lock);
                chn_intr(ch->chan);
                mtx_lock(&sc->lock);
        }
        if (!sc->stopped)
                callout_schedule(&sc->callout, 1);
}

static int
dummy_chan_free(kobj_t obj, void *data)
{
        struct dummy_chan *ch =data;
        uint8_t *buf;

        buf = ch->buf->buf;
        free(buf, M_DEVBUF);

        return (0);
}

static void *
dummy_chan_init(kobj_t obj, void *devinfo, struct snd_dbuf *b,
    struct pcm_channel *c, int dir)
{
        struct dummy_softc *sc;
        struct dummy_chan *ch;
        uint8_t *buf;
        size_t bufsz;

        sc = devinfo;

        mtx_lock(&sc->lock);

        ch = &sc->chans[sc->chnum++];
        ch->sc = sc;
        ch->dir = dir;
        ch->chan = c;
        ch->buf = b;
        ch->caps = &sc->caps;

        mtx_unlock(&sc->lock);

        bufsz = pcm_getbuffersize(sc->dev, 2048, 2048, 65536);
        buf = malloc(bufsz, M_DEVBUF, M_WAITOK | M_ZERO);
        if (sndbuf_setup(ch->buf, buf, bufsz) != 0) {
                dummy_chan_free(obj, ch);
                return (NULL);
        }

        return (ch);
}

static int
dummy_chan_setformat(kobj_t obj, void *data, uint32_t format)
{
        struct dummy_chan *ch = data;
        int i;

        for (i = 0; ch->caps->fmtlist[i]; i++)
                if (format == ch->caps->fmtlist[i])
                        return (0);

        return (EINVAL);
}

static uint32_t
dummy_chan_setspeed(kobj_t obj, void *data, uint32_t speed)
{
        struct dummy_chan *ch = data;

        RANGE(speed, ch->caps->minspeed, ch->caps->maxspeed);

        return (speed);
}

static uint32_t
dummy_chan_setblocksize(kobj_t obj, void *data, uint32_t blocksize)
{
        struct dummy_chan *ch = data;

        return (ch->buf->blksz);
}

static int
dummy_chan_trigger(kobj_t obj, void *data, int go)
{
        struct dummy_chan *ch = data;
        struct dummy_softc *sc = ch->sc;

        mtx_lock(&sc->lock);

        if (sc->stopped) {
                mtx_unlock(&sc->lock);
                return (0);
        }

        switch (go) {
        case PCMTRIG_START:
                ch->ptr = 0;
                ch->run = 1;
                callout_reset(&sc->callout, 1, dummy_chan_io, sc);
                break;
        case PCMTRIG_STOP:
        case PCMTRIG_ABORT:
                ch->run = 0;
                /* If all channels are stopped, stop the callout as well. */
                if (!dummy_active(sc))
                        callout_stop(&sc->callout);
        default:
                break;
        }

        mtx_unlock(&sc->lock);

        return (0);
}

static uint32_t
dummy_chan_getptr(kobj_t obj, void *data)
{
        struct dummy_chan *ch = data;

        return (ch->run ? ch->ptr : 0);
}

static struct pcmchan_caps *
dummy_chan_getcaps(kobj_t obj, void *data)
{
        struct dummy_chan *ch = data;

        return (ch->caps);
}

static kobj_method_t dummy_chan_methods[] = {
        KOBJMETHOD(channel_init,        dummy_chan_init),
        KOBJMETHOD(channel_free,        dummy_chan_free),
        KOBJMETHOD(channel_setformat,   dummy_chan_setformat),
        KOBJMETHOD(channel_setspeed,    dummy_chan_setspeed),
        KOBJMETHOD(channel_setblocksize,dummy_chan_setblocksize),
        KOBJMETHOD(channel_trigger,     dummy_chan_trigger),
        KOBJMETHOD(channel_getptr,      dummy_chan_getptr),
        KOBJMETHOD(channel_getcaps,     dummy_chan_getcaps),
        KOBJMETHOD_END
};

CHANNEL_DECLARE(dummy_chan);

static int
dummy_mixer_init(struct snd_mixer *m)
{
        struct dummy_softc *sc;

        sc = mix_getdevinfo(m);
        if (sc == NULL)
                return (-1);

        pcm_setflags(sc->dev, pcm_getflags(sc->dev) | SD_F_SOFTPCMVOL);
        mix_setdevs(m, SOUND_MASK_PCM | SOUND_MASK_VOLUME | SOUND_MASK_RECLEV);
        mix_setrecdevs(m, SOUND_MASK_RECLEV);

        return (0);
}

static int
dummy_mixer_set(struct snd_mixer *m, unsigned dev, unsigned left, unsigned right)
{
        return (0);
}

static uint32_t
dummy_mixer_setrecsrc(struct snd_mixer *m, uint32_t src)
{
        return (src == SOUND_MASK_RECLEV ? src : 0);
}

static kobj_method_t dummy_mixer_methods[] = {
        KOBJMETHOD(mixer_init,          dummy_mixer_init),
        KOBJMETHOD(mixer_set,           dummy_mixer_set),
        KOBJMETHOD(mixer_setrecsrc,     dummy_mixer_setrecsrc),
        KOBJMETHOD_END
};

MIXER_DECLARE(dummy_mixer);

static uint8_t
dummy_mpu_read(struct mpu401 *arg, void *sc, int reg)
{
        return (0);
}

static void
dummy_mpu_write(struct mpu401 *arg, void *sc, int reg, unsigned char b)
{
}

static int
dummy_mpu_uninit(struct mpu401 *arg, void *cookie)
{
        struct dummy_softc *sc = cookie;

        mtx_lock(&sc->lock);
        sc->mpu_intr = NULL;
        sc->mpu = NULL;
        mtx_unlock(&sc->lock);

        return (0);
}

static kobj_method_t dummy_mpu_methods[] = {
        KOBJMETHOD(mpufoi_read,         dummy_mpu_read),
        KOBJMETHOD(mpufoi_write,        dummy_mpu_write),
        KOBJMETHOD(mpufoi_uninit,       dummy_mpu_uninit),
        KOBJMETHOD_END
};

static DEFINE_CLASS(dummy_mpu, dummy_mpu_methods, 0);

static void
dummy_identify(driver_t *driver, device_t parent)
{
        if (device_find_child(parent, driver->name, DEVICE_UNIT_ANY) != NULL)
                return;
        if (BUS_ADD_CHILD(parent, 0, driver->name, DEVICE_UNIT_ANY) == NULL)
                device_printf(parent, "add child failed\n");
}

static int
dummy_probe(device_t dev)
{
        device_set_desc(dev, "Dummy Audio Device");

        return (0);
}

static int
dummy_attach(device_t dev)
{
        struct dummy_softc *sc;
        char status[SND_STATUSLEN];
        int i = 0;

        sc = device_get_softc(dev);
        sc->dev = dev;
        mtx_init(&sc->lock, device_get_nameunit(dev), "snd_dummy softc",
            MTX_DEF);
        callout_init_mtx(&sc->callout, &sc->lock, 0);

        sc->cap_fmts[0] = SND_FORMAT(AFMT_S32_LE, 2, 0);
        sc->cap_fmts[1] = SND_FORMAT(AFMT_S24_LE, 2, 0);
        sc->cap_fmts[2] = SND_FORMAT(AFMT_S16_LE, 2, 0);
        sc->cap_fmts[3] = 0;
        sc->caps = (struct pcmchan_caps){
                8000,           /* minspeed */
                96000,          /* maxspeed */
                sc->cap_fmts,   /* fmtlist */
                0,              /* caps */
        };

        pcm_setflags(dev, pcm_getflags(dev) | SD_F_MPSAFE);
        pcm_init(dev, sc);
        for (i = 0; i < DUMMY_NPCHAN; i++)
                pcm_addchan(dev, PCMDIR_PLAY, &dummy_chan_class, sc);
        for (i = 0; i < DUMMY_NRCHAN; i++)
                pcm_addchan(dev, PCMDIR_REC, &dummy_chan_class, sc);

        snprintf(status, SND_STATUSLEN, "on %s",
            device_get_nameunit(device_get_parent(dev)));
        if (pcm_register(dev, status))
                return (ENXIO);
        mixer_init(dev, &dummy_mixer_class, sc);

        /*
         * Create an alias so that tests do not need to guess which one is the
         * dummy device if there are more devices present in the system.
         */
        make_dev_alias(sc->info.dsp_dev, "dsp.dummy");

        sc->mpu = mpu401_init(&dummy_mpu_class, sc, dummy_chan_io,
            &sc->mpu_intr);
        if (sc->mpu == NULL)
                return (ENXIO);

        return (0);
}

static int
dummy_detach(device_t dev)
{
        struct dummy_softc *sc = device_get_softc(dev);
        int err;

        mtx_lock(&sc->lock);
        sc->stopped = true;
        mtx_unlock(&sc->lock);
        callout_drain(&sc->callout);
        err = pcm_unregister(dev);
        mpu401_uninit(sc->mpu);
        mtx_destroy(&sc->lock);

        return (err);
}

static device_method_t dummy_methods[] = {
        /* Device interface */
        DEVMETHOD(device_identify,      dummy_identify),
        DEVMETHOD(device_probe,         dummy_probe),
        DEVMETHOD(device_attach,        dummy_attach),
        DEVMETHOD(device_detach,        dummy_detach),
        DEVMETHOD_END
};

static driver_t dummy_driver = {
        "pcm",
        dummy_methods,
        sizeof(struct dummy_softc),
};

DRIVER_MODULE(snd_dummy, nexus, dummy_driver, 0, 0);
MODULE_DEPEND(snd_dummy, sound, SOUND_MINVER, SOUND_PREFVER, SOUND_MAXVER);
MODULE_VERSION(snd_dummy, 1);