/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2005-2009 Ariff Abdullah <ariff@FreeBSD.org>
 * Portions Copyright (c) Ryan Beasley <ryan.beasley@gmail.com> - GSoC 2006
 * Copyright (c) 1999 Cameron Grant <cg@FreeBSD.org>
 * All rights reserved.
 * Copyright (c) 2024-2025 The FreeBSD Foundation
 *
 * Portions of this software were 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.
 */

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

#include <dev/sound/pcm/sound.h>
#include <dev/sound/pcm/vchan.h>
#include <sys/ctype.h>
#include <sys/lock.h>
#include <sys/rwlock.h>
#include <sys/sysent.h>

#include <vm/vm.h>
#include <vm/vm_object.h>
#include <vm/vm_page.h>
#include <vm/vm_pager.h>

struct dsp_cdevpriv {
        struct snddev_info *sc;
        struct pcm_channel *rdch;
        struct pcm_channel *wrch;
};

static int dsp_mmap_allow_prot_exec = 0;
SYSCTL_INT(_hw_snd, OID_AUTO, compat_linux_mmap, CTLFLAG_RWTUN,
    &dsp_mmap_allow_prot_exec, 0,
    "linux mmap compatibility (-1=force disable 0=auto 1=force enable)");

static int dsp_basename_clone = 1;
SYSCTL_INT(_hw_snd, OID_AUTO, basename_clone, CTLFLAG_RWTUN,
    &dsp_basename_clone, 0,
    "DSP basename cloning (0: Disable; 1: Enabled)");

#define DSP_REGISTERED(x)       (PCM_REGISTERED(x) && (x)->dsp_dev != NULL)

#define DSP_F_VALID(x)          ((x) & (FREAD | FWRITE))
#define DSP_F_DUPLEX(x)         (((x) & (FREAD | FWRITE)) == (FREAD | FWRITE))
#define DSP_F_SIMPLEX(x)        (!DSP_F_DUPLEX(x))
#define DSP_F_READ(x)           ((x) & FREAD)
#define DSP_F_WRITE(x)          ((x) & FWRITE)

static d_open_t dsp_open;
static d_read_t dsp_read;
static d_write_t dsp_write;
static d_ioctl_t dsp_ioctl;
static d_poll_t dsp_poll;
static d_mmap_t dsp_mmap;
static d_mmap_single_t dsp_mmap_single;
static d_kqfilter_t dsp_kqfilter;

struct cdevsw dsp_cdevsw = {
        .d_version      = D_VERSION,
        .d_open         = dsp_open,
        .d_read         = dsp_read,
        .d_write        = dsp_write,
        .d_ioctl        = dsp_ioctl,
        .d_poll         = dsp_poll,
        .d_kqfilter     = dsp_kqfilter,
        .d_mmap         = dsp_mmap,
        .d_mmap_single  = dsp_mmap_single,
        .d_name         = "dsp",
};

static eventhandler_tag dsp_ehtag = NULL;

static int dsp_oss_syncgroup(struct pcm_channel *wrch, struct pcm_channel *rdch, oss_syncgroup *group);
static int dsp_oss_syncstart(int sg_id);
static int dsp_oss_policy(struct pcm_channel *wrch, struct pcm_channel *rdch, int policy);
static int dsp_oss_cookedmode(struct pcm_channel *wrch, struct pcm_channel *rdch, int enabled);
static int dsp_oss_getchnorder(struct pcm_channel *wrch, struct pcm_channel *rdch, unsigned long long *map);
static int dsp_oss_setchnorder(struct pcm_channel *wrch, struct pcm_channel *rdch, unsigned long long *map);
static int dsp_oss_getchannelmask(struct pcm_channel *wrch, struct pcm_channel *rdch, int *mask);
#ifdef OSSV4_EXPERIMENT
static int dsp_oss_getlabel(struct pcm_channel *wrch, struct pcm_channel *rdch, oss_label_t *label);
static int dsp_oss_setlabel(struct pcm_channel *wrch, struct pcm_channel *rdch, oss_label_t *label);
static int dsp_oss_getsong(struct pcm_channel *wrch, struct pcm_channel *rdch, oss_longname_t *song);
static int dsp_oss_setsong(struct pcm_channel *wrch, struct pcm_channel *rdch, oss_longname_t *song);
static int dsp_oss_setname(struct pcm_channel *wrch, struct pcm_channel *rdch, oss_longname_t *name);
#endif

int
dsp_make_dev(device_t dev)
{
        struct make_dev_args devargs;
        struct snddev_info *sc;
        int err, unit;

        sc = device_get_softc(dev);
        unit = device_get_unit(dev);

        make_dev_args_init(&devargs);
        devargs.mda_devsw = &dsp_cdevsw;
        devargs.mda_uid = UID_ROOT;
        devargs.mda_gid = GID_WHEEL;
        devargs.mda_mode = 0666;
        devargs.mda_si_drv1 = sc;
        err = make_dev_s(&devargs, &sc->dsp_dev, "dsp%d", unit);
        if (err != 0) {
                device_printf(dev, "failed to create dsp%d: error %d",
                    unit, err);
                return (ENXIO);
        }

        return (0);
}

void
dsp_destroy_dev(device_t dev)
{
        struct snddev_info *d;

        d = device_get_softc(dev);
        destroy_dev(d->dsp_dev);
}

static void
dsp_lock_chans(struct dsp_cdevpriv *priv, uint32_t prio)
{
        if (priv->rdch != NULL && DSP_F_READ(prio))
                CHN_LOCK(priv->rdch);
        if (priv->wrch != NULL && DSP_F_WRITE(prio))
                CHN_LOCK(priv->wrch);
}

static void
dsp_unlock_chans(struct dsp_cdevpriv *priv, uint32_t prio)
{
        if (priv->rdch != NULL && DSP_F_READ(prio))
                CHN_UNLOCK(priv->rdch);
        if (priv->wrch != NULL && DSP_F_WRITE(prio))
                CHN_UNLOCK(priv->wrch);
}

static int
dsp_chn_alloc(struct snddev_info *d, struct pcm_channel **ch, int direction,
    int flags, struct thread *td)
{
        struct pcm_channel *c;
        char *comm;
        pid_t pid;
        int err;
        bool vdir_enabled;

        KASSERT(d != NULL && ch != NULL &&
            (direction == PCMDIR_PLAY || direction == PCMDIR_REC),
            ("%s(): invalid d=%p ch=%p direction=%d",
            __func__, d, ch, direction));
        PCM_BUSYASSERT(d);

        pid = td->td_proc->p_pid;
        comm = td->td_proc->p_comm;

        vdir_enabled = (direction == PCMDIR_PLAY && d->flags & SD_F_PVCHANS) ||
            (direction == PCMDIR_REC && d->flags & SD_F_RVCHANS);

        *ch = NULL;
        CHN_FOREACH(c, d, channels.pcm.primary) {
                CHN_LOCK(c);
                if (c->direction != direction) {
                        CHN_UNLOCK(c);
                        continue;
                }
                /* Find an available primary channel to use. */
                if ((c->flags & CHN_F_BUSY) == 0 ||
                    (vdir_enabled && (c->flags & CHN_F_HAS_VCHAN)))
                        break;
                CHN_UNLOCK(c);
        }
        if (c == NULL)
                return (EBUSY);

        /*
         * We can have the following cases:
         * - vchans are enabled, add a new vchan to the primary channel.
         * - vchans are disabled, use the primary channel directly.
         */
        if (vdir_enabled && ((c->flags & CHN_F_BUSY) == 0 ||
            c->flags & CHN_F_HAS_VCHAN)) {
                err = vchan_create(c, ch);
                CHN_UNLOCK(c);
                if (err != 0)
                        return (err);
                CHN_LOCK(*ch);
        } else if ((c->flags & CHN_F_BUSY) == 0) {
                *ch = c;
        } else {
                CHN_UNLOCK(c);
                return (ENODEV);
        }

        (*ch)->flags |= CHN_F_BUSY;
        if (flags & O_NONBLOCK)
                (*ch)->flags |= CHN_F_NBIO;
        if (flags & O_EXCL)
                (*ch)->flags |= CHN_F_EXCLUSIVE;
        (*ch)->pid = pid;
        strlcpy((*ch)->comm, (comm != NULL) ? comm : CHN_COMM_UNKNOWN,
            sizeof((*ch)->comm));

        if ((err = chn_reset(*ch, (*ch)->format, (*ch)->speed)) != 0)
                return (err);
        chn_vpc_reset(*ch, SND_VOL_C_PCM, 0);

        CHN_UNLOCK(*ch);

        return (0);
}

static void
dsp_close(void *data)
{
        struct dsp_cdevpriv *priv = data;
        struct pcm_channel *rdch, *wrch, *parent;
        struct snddev_info *d;
        int sg_ids;

        if (priv == NULL)
                return;

        d = priv->sc;
        /* At this point pcm_unregister() will destroy all channels anyway. */
        if (!DSP_REGISTERED(d))
                goto skip;

        PCM_GIANT_ENTER(d);

        PCM_LOCK(d);
        PCM_WAIT(d);
        PCM_ACQUIRE(d);

        rdch = priv->rdch;
        wrch = priv->wrch;

        if (rdch != NULL)
                CHN_REMOVE(d, rdch, channels.pcm.opened);
        if (wrch != NULL)
                CHN_REMOVE(d, wrch, channels.pcm.opened);

        if (rdch != NULL || wrch != NULL) {
                PCM_UNLOCK(d);
                if (rdch != NULL) {
                        /*
                         * The channel itself need not be locked because:
                         *   a)  Adding a channel to a syncgroup happens only
                         *       in dsp_ioctl(), which cannot run concurrently
                         *       to dsp_close().
                         *   b)  The syncmember pointer (sm) is protected by
                         *       the global syncgroup list lock.
                         *   c)  A channel can't just disappear, invalidating
                         *       pointers, unless it's closed/dereferenced
                         *       first.
                         */
                        PCM_SG_LOCK();
                        sg_ids = chn_syncdestroy(rdch);
                        PCM_SG_UNLOCK();
                        if (sg_ids != 0)
                                free_unr(pcmsg_unrhdr, sg_ids);

                        /*
                         * Go through the channel abort/flush path for both
                         * primary and virtual channels to ensure that, in the
                         * case of vchans, the stream is always properly
                         * stopped, and the primary channels do not keep being
                         * interrupted even if all vchans are gone.
                         */
                        CHN_LOCK(rdch);
                        chn_abort(rdch); /* won't sleep */
                        rdch->flags &= ~(CHN_F_RUNNING | CHN_F_MMAP |
                            CHN_F_DEAD | CHN_F_EXCLUSIVE | CHN_F_NBIO);
                        chn_reset(rdch, 0, 0);
                        chn_release(rdch);
                        if (rdch->flags & CHN_F_VIRTUAL) {
                                parent = rdch->parentchannel;
                                CHN_LOCK(parent);
                                CHN_LOCK(rdch);
                                vchan_destroy(rdch);
                                CHN_UNLOCK(parent);
                        }
                }
                if (wrch != NULL) {
                        /*
                         * Please see block above.
                         */
                        PCM_SG_LOCK();
                        sg_ids = chn_syncdestroy(wrch);
                        PCM_SG_UNLOCK();
                        if (sg_ids != 0)
                                free_unr(pcmsg_unrhdr, sg_ids);

                        CHN_LOCK(wrch);
                        chn_flush(wrch); /* may sleep */
                        wrch->flags &= ~(CHN_F_RUNNING | CHN_F_MMAP |
                            CHN_F_DEAD | CHN_F_EXCLUSIVE | CHN_F_NBIO);
                        chn_reset(wrch, 0, 0);
                        chn_release(wrch);
                        if (wrch->flags & CHN_F_VIRTUAL) {
                                parent = wrch->parentchannel;
                                CHN_LOCK(parent);
                                CHN_LOCK(wrch);
                                vchan_destroy(wrch);
                                CHN_UNLOCK(parent);
                        }
                }
                PCM_LOCK(d);
        }

        PCM_RELEASE(d);
        PCM_UNLOCK(d);

        PCM_GIANT_LEAVE(d);
skip:
        free(priv, M_DEVBUF);
        priv = NULL;
}

static int
dsp_open(struct cdev *i_dev, int flags, int mode, struct thread *td)
{
        struct dsp_cdevpriv *priv;
        struct pcm_channel *ch;
        struct snddev_info *d;
        int error, dir;

        /* Kind of impossible.. */
        if (i_dev == NULL || td == NULL)
                return (ENODEV);

        d = i_dev->si_drv1;
        if (!DSP_REGISTERED(d))
                return (EBADF);

        if (PCM_CHANCOUNT(d) >= PCM_MAXCHANS)
                return (ENOMEM);

        priv = malloc(sizeof(*priv), M_DEVBUF, M_WAITOK | M_ZERO);
        priv->sc = d;

        error = devfs_set_cdevpriv(priv, dsp_close);
        if (error != 0)
                return (error);

        PCM_GIANT_ENTER(d);

        /* Lock snddev so nobody else can monkey with it. */
        PCM_LOCK(d);
        PCM_WAIT(d);

        error = 0;
        if (!DSP_F_VALID(flags))
                error = EINVAL;
        else if (!DSP_F_DUPLEX(flags) &&
            ((DSP_F_READ(flags) && d->reccount == 0) ||
            (DSP_F_WRITE(flags) && d->playcount == 0)))
                error = ENOTSUP;
        if (pcm_getflags(d->dev) & SD_F_SIMPLEX) {
                if (DSP_F_DUPLEX(flags)) {
                        /*
                         * If no channels are opened yet, and we request
                         * DUPLEX, limit to playback only, otherwise open one
                         * channel in a direction that already exists.
                         */
                        if (CHN_EMPTY(d, channels.pcm.opened)) {
                                if (d->playcount > 0)
                                        flags &= ~FREAD;
                                else if (d->reccount > 0)
                                        flags &= ~FWRITE;
                        } else {
                                ch = CHN_FIRST(d, channels.pcm.opened);
                                if (ch->direction == PCMDIR_PLAY)
                                        flags &= ~FREAD;
                                else if (ch->direction == PCMDIR_REC)
                                        flags &= ~FWRITE;
                        }
                } else if (!CHN_EMPTY(d, channels.pcm.opened)) {
                        /*
                         * If we requested SIMPLEX, make sure we do not open a
                         * channel in the opposite direction.
                         */
                        ch = CHN_FIRST(d, channels.pcm.opened);
                        dir = DSP_F_READ(flags) ? PCMDIR_REC : PCMDIR_PLAY;
                        if (ch->direction != dir)
                                error = ENOTSUP;
                }
        }
        if (error != 0) {
                PCM_UNLOCK(d);
                PCM_GIANT_EXIT(d);
                return (error);
        }

        /*
         * That is just enough. Acquire and unlock pcm lock so
         * the other will just have to wait until we finish doing
         * everything.
         */
        PCM_ACQUIRE(d);
        PCM_UNLOCK(d);

        if (DSP_F_WRITE(flags)) {
                error = dsp_chn_alloc(d, &priv->wrch, PCMDIR_PLAY, flags, td);
                if (error != 0) {
                        PCM_RELEASE_QUICK(d);
                        PCM_GIANT_EXIT(d);
                        return (error);
                }
                PCM_LOCK(d);
                CHN_INSERT_HEAD(d, priv->wrch, channels.pcm.opened);
                PCM_UNLOCK(d);
        }
        if (DSP_F_READ(flags)) {
                error = dsp_chn_alloc(d, &priv->rdch, PCMDIR_REC, flags, td);
                if (error != 0) {
                        PCM_RELEASE_QUICK(d);
                        PCM_GIANT_EXIT(d);
                        return (error);
                }
                PCM_LOCK(d);
                CHN_INSERT_HEAD(d, priv->rdch, channels.pcm.opened);
                PCM_UNLOCK(d);
        }

        PCM_RELEASE_QUICK(d);
        PCM_GIANT_LEAVE(d);

        return (0);
}

static __inline int
dsp_io_ops(struct dsp_cdevpriv *priv, struct uio *buf)
{
        struct snddev_info *d;
        struct pcm_channel *ch;
        int (*chn_io)(struct pcm_channel *, struct uio *);
        int ret;

        d = priv->sc;
        if (!DSP_REGISTERED(d))
                return (EBADF);

        PCM_GIANT_ENTER(d);

        switch (buf->uio_rw) {
        case UIO_READ:
                ch = priv->rdch;
                chn_io = chn_read;
                break;
        case UIO_WRITE:
                ch = priv->wrch;
                chn_io = chn_write;
                break;
        }
        if (ch == NULL) {
                PCM_GIANT_EXIT(d);
                return (ENXIO);
        }
        CHN_LOCK(ch);

        if (!(ch->flags & CHN_F_BUSY) ||
            (ch->flags & (CHN_F_MMAP | CHN_F_DEAD))) {
                CHN_UNLOCK(ch);
                PCM_GIANT_EXIT(d);
                return (ENXIO);
        } else if (!(ch->flags & CHN_F_RUNNING))
                ch->flags |= CHN_F_RUNNING;

        /*
         * chn_read/write must give up channel lock in order to copy bytes
         * from/to userland, so up the "in progress" counter to make sure
         * someone else doesn't come along and muss up the buffer.
         */
        ch->inprog++;
        ret = chn_io(ch, buf);
        ch->inprog--;

        CHN_BROADCAST(&ch->cv);
        CHN_UNLOCK(ch);

        PCM_GIANT_LEAVE(d);

        return (ret);
}

static int
dsp_read(struct cdev *i_dev, struct uio *buf, int flag)
{
        struct dsp_cdevpriv *priv;
        int err;

        if ((err = devfs_get_cdevpriv((void **)&priv)) != 0)
                return (err);
        return (dsp_io_ops(priv, buf));
}

static int
dsp_write(struct cdev *i_dev, struct uio *buf, int flag)
{
        struct dsp_cdevpriv *priv;
        int err;

        if ((err = devfs_get_cdevpriv((void **)&priv)) != 0)
                return (err);
        return (dsp_io_ops(priv, buf));
}

static int
dsp_ioctl_channel(struct dsp_cdevpriv *priv, struct pcm_channel *ch,
    u_long cmd, caddr_t arg)
{
        struct snddev_info *d;
        struct pcm_channel *rdch, *wrch;
        int j, left, right, center, mute;

        d = priv->sc;
        if (!PCM_REGISTERED(d) || !(pcm_getflags(d->dev) & SD_F_VPC))
                return (-1);

        PCM_UNLOCKASSERT(d);

        j = cmd & 0xff;

        rdch = priv->rdch;
        wrch = priv->wrch;

        if (ch == NULL) {
                if (j == SOUND_MIXER_RECLEV && rdch != NULL)
                        ch = rdch;
                else if (j == SOUND_MIXER_PCM && wrch != NULL)
                        ch = wrch;
        }

        if (ch == NULL)
                return (EINVAL);

        CHN_LOCK(ch);
        if (!(ch->feederflags & (1 << FEEDER_VOLUME))) {
                CHN_UNLOCK(ch);
                return (EINVAL);
        }

        switch (cmd & ~0xff) {
        case MIXER_WRITE(0):
                switch (j) {
                case SOUND_MIXER_MUTE:
                        if (ch->direction == PCMDIR_REC) {
                                chn_setmute_multi(ch, SND_VOL_C_PCM, (*(int *)arg & SOUND_MASK_RECLEV) != 0);
                        } else {
                                chn_setmute_multi(ch, SND_VOL_C_PCM, (*(int *)arg & SOUND_MASK_PCM) != 0);
                        }
                        break;
                case SOUND_MIXER_PCM:
                        if (ch->direction != PCMDIR_PLAY)
                                break;
                        left = *(int *)arg & 0x7f;
                        right = ((*(int *)arg) >> 8) & 0x7f;
                        center = (left + right) >> 1;
                        chn_setvolume_multi(ch, SND_VOL_C_PCM,
                            left, right, center);
                        break;
                case SOUND_MIXER_RECLEV:
                        if (ch->direction != PCMDIR_REC)
                                break;
                        left = *(int *)arg & 0x7f;
                        right = ((*(int *)arg) >> 8) & 0x7f;
                        center = (left + right) >> 1;
                        chn_setvolume_multi(ch, SND_VOL_C_PCM,
                            left, right, center);
                        break;
                default:
                        /* ignore all other mixer writes */
                        break;
                }
                break;

        case MIXER_READ(0):
                switch (j) {
                case SOUND_MIXER_MUTE:
                        mute = chn_getmute_matrix(ch,
                            SND_VOL_C_PCM, SND_CHN_T_FL) ||
                            chn_getmute_matrix(ch, SND_VOL_C_PCM, SND_CHN_T_FR);
                        if (ch->direction == PCMDIR_REC) {
                                *(int *)arg = mute << SOUND_MIXER_RECLEV;
                        } else {
                                *(int *)arg = mute << SOUND_MIXER_PCM;
                        }
                        break;
                case SOUND_MIXER_PCM:
                        if (ch->direction != PCMDIR_PLAY)
                                break;
                        *(int *)arg = chn_getvolume_matrix(ch,
                            SND_VOL_C_PCM, SND_CHN_T_FL);
                        *(int *)arg |= chn_getvolume_matrix(ch,
                            SND_VOL_C_PCM, SND_CHN_T_FR) << 8;
                        break;
                case SOUND_MIXER_RECLEV:
                        if (ch->direction != PCMDIR_REC)
                                break;
                        *(int *)arg = chn_getvolume_matrix(ch,
                            SND_VOL_C_PCM, SND_CHN_T_FL);
                        *(int *)arg |= chn_getvolume_matrix(ch,
                            SND_VOL_C_PCM, SND_CHN_T_FR) << 8;
                        break;
                case SOUND_MIXER_DEVMASK:
                case SOUND_MIXER_CAPS:
                case SOUND_MIXER_STEREODEVS:
                        if (ch->direction == PCMDIR_REC)
                                *(int *)arg = SOUND_MASK_RECLEV;
                        else
                                *(int *)arg = SOUND_MASK_PCM;
                        break;
                default:
                        *(int *)arg = 0;
                        break;
                }
                break;

        default:
                break;
        }
        CHN_UNLOCK(ch);
        return (0);
}

#ifdef COMPAT_FREEBSD32
typedef struct _snd_chan_param32 {
        uint32_t        play_rate;
        uint32_t        rec_rate;
        uint32_t        play_format;
        uint32_t        rec_format;
} snd_chan_param32;
#define AIOGFMT32    _IOC_NEWTYPE(AIOGFMT, snd_chan_param32)
#define AIOSFMT32    _IOC_NEWTYPE(AIOSFMT, snd_chan_param32)

typedef struct _snd_capabilities32 {
        uint32_t        rate_min, rate_max;
        uint32_t        formats;
        uint32_t        bufsize;
        uint32_t        mixers;
        uint32_t        inputs;
        uint16_t        left, right;
} snd_capabilities32;
#define AIOGCAP32 _IOC_NEWTYPE(AIOGCAP, snd_capabilities32)

typedef struct audio_errinfo32
{
        int32_t         play_underruns;
        int32_t         rec_overruns;
        uint32_t        play_ptradjust;
        uint32_t        rec_ptradjust;
        int32_t         play_errorcount;
        int32_t         rec_errorcount;
        int32_t         play_lasterror;
        int32_t         rec_lasterror;
        int32_t         play_errorparm;
        int32_t         rec_errorparm;
        int32_t         filler[16];
} audio_errinfo32;
#define SNDCTL_DSP_GETERROR32 _IOC_NEWTYPE(SNDCTL_DSP_GETERROR, audio_errinfo32)
#endif

static int
dsp_ioctl(struct cdev *i_dev, u_long cmd, caddr_t arg, int mode,
    struct thread *td)
{
        struct dsp_cdevpriv *priv;
        struct pcm_channel *chn, *rdch, *wrch;
        struct snddev_info *d;
        u_long xcmd;
        int *arg_i, ret, tmp, err;

        if ((err = devfs_get_cdevpriv((void **)&priv)) != 0)
                return (err);

        d = priv->sc;
        if (!DSP_REGISTERED(d))
                return (EBADF);

        PCM_GIANT_ENTER(d);

        arg_i = (int *)arg;
        ret = 0;
        xcmd = 0;
        chn = NULL;

        if (IOCGROUP(cmd) == 'M') {
                if (cmd == OSS_GETVERSION) {
                        *arg_i = SOUND_VERSION;
                        PCM_GIANT_EXIT(d);
                        return (0);
                }
                ret = dsp_ioctl_channel(priv, NULL, cmd, arg);
                if (ret != -1) {
                        PCM_GIANT_EXIT(d);
                        return (ret);
                }

                if (d->mixer_dev != NULL) {
                        PCM_ACQUIRE_QUICK(d);
                        ret = mixer_ioctl_cmd(d->mixer_dev, cmd, arg, -1, td,
                            MIXER_CMD_DIRECT);
                        PCM_RELEASE_QUICK(d);
                } else
                        ret = EBADF;

                PCM_GIANT_EXIT(d);

                return (ret);
        }

        /*
         * Certain ioctls may be made on any type of device (audio, mixer,
         * and MIDI).  Handle those special cases here.
         */
        if (IOCGROUP(cmd) == 'X') {
                PCM_ACQUIRE_QUICK(d);
                switch(cmd) {
                case SNDCTL_SYSINFO:
                        sound_oss_sysinfo((oss_sysinfo *)arg);
                        break;
                case SNDCTL_CARDINFO:
                        ret = sound_oss_card_info((oss_card_info *)arg);
                        break;
                case SNDCTL_AUDIOINFO:
                        ret = dsp_oss_audioinfo(i_dev, (oss_audioinfo *)arg,
                            false);
                        break;
                case SNDCTL_AUDIOINFO_EX:
                        ret = dsp_oss_audioinfo(i_dev, (oss_audioinfo *)arg,
                            true);
                        break;
                case SNDCTL_ENGINEINFO:
                        ret = dsp_oss_engineinfo(i_dev, (oss_audioinfo *)arg);
                        break;
                case SNDCTL_MIXERINFO:
                        ret = mixer_oss_mixerinfo(i_dev, (oss_mixerinfo *)arg);
                        break;
                default:
                        ret = EINVAL;
                }
                PCM_RELEASE_QUICK(d);
                PCM_GIANT_EXIT(d);
                return (ret);
        }

        rdch = priv->rdch;
        wrch = priv->wrch;

        if (wrch != NULL && (wrch->flags & CHN_F_DEAD))
                wrch = NULL;
        if (rdch != NULL && (rdch->flags & CHN_F_DEAD))
                rdch = NULL;

        if (wrch == NULL && rdch == NULL) {
                PCM_GIANT_EXIT(d);
                return (EINVAL);
        }

        switch(cmd) {
        case AIONWRITE: /* how many bytes can write ? */
                if (wrch) {
                        CHN_LOCK(wrch);
/*
                if (wrch && wrch->bufhard.dl)
                        while (chn_wrfeed(wrch) == 0);
*/
                        *arg_i = sndbuf_getfree(wrch->bufsoft);
                        CHN_UNLOCK(wrch);
                } else {
                        *arg_i = 0;
                        ret = EINVAL;
                }
                break;

        case AIOSSIZE:     /* set the current blocksize */
                {
                        struct snd_size *p = (struct snd_size *)arg;

                        p->play_size = 0;
                        p->rec_size = 0;
                        PCM_ACQUIRE_QUICK(d);
                        if (wrch) {
                                CHN_LOCK(wrch);
                                chn_setblocksize(wrch, 2, p->play_size);
                                p->play_size = wrch->bufsoft->blksz;
                                CHN_UNLOCK(wrch);
                        }
                        if (rdch) {
                                CHN_LOCK(rdch);
                                chn_setblocksize(rdch, 2, p->rec_size);
                                p->rec_size = rdch->bufsoft->blksz;
                                CHN_UNLOCK(rdch);
                        }
                        PCM_RELEASE_QUICK(d);
                }
                break;
        case AIOGSIZE:  /* get the current blocksize */
                {
                        struct snd_size *p = (struct snd_size *)arg;

                        if (wrch) {
                                CHN_LOCK(wrch);
                                p->play_size = wrch->bufsoft->blksz;
                                CHN_UNLOCK(wrch);
                        }
                        if (rdch) {
                                CHN_LOCK(rdch);
                                p->rec_size = rdch->bufsoft->blksz;
                                CHN_UNLOCK(rdch);
                        }
                }
                break;

        case AIOSFMT:
        case AIOGFMT:
#ifdef COMPAT_FREEBSD32
        case AIOSFMT32:
        case AIOGFMT32:
#endif
                {
                        snd_chan_param *p = (snd_chan_param *)arg;

#ifdef COMPAT_FREEBSD32
                        snd_chan_param32 *p32 = (snd_chan_param32 *)arg;
                        snd_chan_param param;

                        if (cmd == AIOSFMT32) {
                                p = &param;
                                p->play_rate = p32->play_rate;
                                p->rec_rate = p32->rec_rate;
                                p->play_format = p32->play_format;
                                p->rec_format = p32->rec_format;
                        }
#endif
                        if (cmd == AIOSFMT &&
                            ((p->play_format != 0 && p->play_rate == 0) ||
                            (p->rec_format != 0 && p->rec_rate == 0))) {
                                ret = EINVAL;
                                break;
                        }
                        PCM_ACQUIRE_QUICK(d);
                        if (wrch) {
                                CHN_LOCK(wrch);
                                if (cmd == AIOSFMT && p->play_format != 0) {
                                        chn_setformat(wrch,
                                            SND_FORMAT(p->play_format,
                                            AFMT_CHANNEL(wrch->format),
                                            AFMT_EXTCHANNEL(wrch->format)));
                                        chn_setspeed(wrch, p->play_rate);
                                }
                                p->play_rate = wrch->speed;
                                p->play_format = AFMT_ENCODING(wrch->format);
                                CHN_UNLOCK(wrch);
                        } else {
                                p->play_rate = 0;
                                p->play_format = 0;
                        }
                        if (rdch) {
                                CHN_LOCK(rdch);
                                if (cmd == AIOSFMT && p->rec_format != 0) {
                                        chn_setformat(rdch,
                                            SND_FORMAT(p->rec_format,
                                            AFMT_CHANNEL(rdch->format),
                                            AFMT_EXTCHANNEL(rdch->format)));
                                        chn_setspeed(rdch, p->rec_rate);
                                }
                                p->rec_rate = rdch->speed;
                                p->rec_format = AFMT_ENCODING(rdch->format);
                                CHN_UNLOCK(rdch);
                        } else {
                                p->rec_rate = 0;
                                p->rec_format = 0;
                        }
                        PCM_RELEASE_QUICK(d);
#ifdef COMPAT_FREEBSD32
                        if (cmd == AIOSFMT32 || cmd == AIOGFMT32) {
                                p32->play_rate = p->play_rate;
                                p32->rec_rate = p->rec_rate;
                                p32->play_format = p->play_format;
                                p32->rec_format = p->rec_format;
                        }
#endif
                }
                break;

        case AIOGCAP:     /* get capabilities */
#ifdef COMPAT_FREEBSD32
        case AIOGCAP32:
#endif
                {
                        snd_capabilities *p = (snd_capabilities *)arg;
                        struct pcmchan_caps *pcaps = NULL, *rcaps = NULL;
                        struct cdev *pdev;
#ifdef COMPAT_FREEBSD32
                        snd_capabilities32 *p32 = (snd_capabilities32 *)arg;
                        snd_capabilities capabilities;

                        if (cmd == AIOGCAP32) {
                                p = &capabilities;
                                p->rate_min = p32->rate_min;
                                p->rate_max = p32->rate_max;
                                p->formats = p32->formats;
                                p->bufsize = p32->bufsize;
                                p->mixers = p32->mixers;
                                p->inputs = p32->inputs;
                                p->left = p32->left;
                                p->right = p32->right;
                        }
#endif
                        PCM_LOCK(d);
                        if (rdch) {
                                CHN_LOCK(rdch);
                                rcaps = chn_getcaps(rdch);
                        }
                        if (wrch) {
                                CHN_LOCK(wrch);
                                pcaps = chn_getcaps(wrch);
                        }
                        p->rate_min = max(rcaps? rcaps->minspeed : 0,
                                          pcaps? pcaps->minspeed : 0);
                        p->rate_max = min(rcaps? rcaps->maxspeed : 1000000,
                                          pcaps? pcaps->maxspeed : 1000000);
                        p->bufsize = min(rdch? rdch->bufsoft->bufsize : 1000000,
                                         wrch? wrch->bufsoft->bufsize : 1000000);
                        /* XXX bad on sb16 */
                        p->formats = (rdch? chn_getformats(rdch) : 0xffffffff) &
                                     (wrch? chn_getformats(wrch) : 0xffffffff);
                        if (rdch && wrch) {
                                p->formats |=
                                    (pcm_getflags(d->dev) & SD_F_SIMPLEX) ? 0 :
                                    AFMT_FULLDUPLEX;
                        }
                        pdev = d->mixer_dev;
                        p->mixers = 1; /* default: one mixer */
                        p->inputs = pdev->si_drv1? mix_getdevs(pdev->si_drv1) : 0;
                        p->left = p->right = 100;
                        if (wrch)
                                CHN_UNLOCK(wrch);
                        if (rdch)
                                CHN_UNLOCK(rdch);
                        PCM_UNLOCK(d);
#ifdef COMPAT_FREEBSD32
                        if (cmd == AIOGCAP32) {
                                p32->rate_min = p->rate_min;
                                p32->rate_max = p->rate_max;
                                p32->formats = p->formats;
                                p32->bufsize = p->bufsize;
                                p32->mixers = p->mixers;
                                p32->inputs = p->inputs;
                                p32->left = p->left;
                                p32->right = p->right;
                        }
#endif
                }
                break;

        case AIOSTOP:
                if (*arg_i == AIOSYNC_PLAY && wrch) {
                        CHN_LOCK(wrch);
                        *arg_i = chn_abort(wrch);
                        CHN_UNLOCK(wrch);
                } else if (*arg_i == AIOSYNC_CAPTURE && rdch) {
                        CHN_LOCK(rdch);
                        *arg_i = chn_abort(rdch);
                        CHN_UNLOCK(rdch);
                } else {
                        printf("AIOSTOP: bad channel 0x%x\n", *arg_i);
                        *arg_i = 0;
                }
                break;

        case AIOSYNC:
                printf("AIOSYNC chan 0x%03lx pos %lu unimplemented\n",
                        ((snd_sync_parm *)arg)->chan, ((snd_sync_parm *)arg)->pos);
                break;
        case FIONREAD: /* get # bytes to read */
                if (rdch) {
                        CHN_LOCK(rdch);
/*                      if (rdch && rdch->bufhard.dl)
                                while (chn_rdfeed(rdch) == 0);
*/
                        *arg_i = sndbuf_getready(rdch->bufsoft);
                        CHN_UNLOCK(rdch);
                } else {
                        *arg_i = 0;
                        ret = EINVAL;
                }
                break;

        case FIOASYNC: /*set/clear async i/o */
                DEB( printf("FIOASYNC\n") ; )
                break;

        case SNDCTL_DSP_NONBLOCK: /* set non-blocking i/o */
        case FIONBIO: /* set/clear non-blocking i/o */
                if (rdch) {
                        CHN_LOCK(rdch);
                        if (cmd == SNDCTL_DSP_NONBLOCK || *arg_i)
                                rdch->flags |= CHN_F_NBIO;
                        else
                                rdch->flags &= ~CHN_F_NBIO;
                        CHN_UNLOCK(rdch);
                }
                if (wrch) {
                        CHN_LOCK(wrch);
                        if (cmd == SNDCTL_DSP_NONBLOCK || *arg_i)
                                wrch->flags |= CHN_F_NBIO;
                        else
                                wrch->flags &= ~CHN_F_NBIO;
                        CHN_UNLOCK(wrch);
                }
                break;

        case SNDCTL_DSP_GETBLKSIZE:
                chn = wrch ? wrch : rdch;
                if (chn) {
                        CHN_LOCK(chn);
                        *arg_i = chn->bufsoft->blksz;
                        CHN_UNLOCK(chn);
                } else {
                        *arg_i = 0;
                        ret = EINVAL;
                }
                break;

        case SNDCTL_DSP_SETBLKSIZE:
                RANGE(*arg_i, 16, 65536);
                PCM_ACQUIRE_QUICK(d);
                if (wrch) {
                        CHN_LOCK(wrch);
                        chn_setblocksize(wrch, 2, *arg_i);
                        CHN_UNLOCK(wrch);
                }
                if (rdch) {
                        CHN_LOCK(rdch);
                        chn_setblocksize(rdch, 2, *arg_i);
                        CHN_UNLOCK(rdch);
                }
                PCM_RELEASE_QUICK(d);
                break;

        case SNDCTL_DSP_RESET:
                DEB(printf("dsp reset\n"));
                if (wrch) {
                        CHN_LOCK(wrch);
                        chn_abort(wrch);
                        chn_resetbuf(wrch);
                        CHN_UNLOCK(wrch);
                }
                if (rdch) {
                        CHN_LOCK(rdch);
                        chn_abort(rdch);
                        chn_resetbuf(rdch);
                        CHN_UNLOCK(rdch);
                }
                break;

        case SNDCTL_DSP_SYNC:
                DEB(printf("dsp sync\n"));
                /* chn_sync may sleep */
                if (wrch) {
                        CHN_LOCK(wrch);
                        chn_sync(wrch, 0);
                        CHN_UNLOCK(wrch);
                }
                break;

        case SNDCTL_DSP_SPEED:
                /* chn_setspeed may sleep */
                tmp = 0;
                PCM_ACQUIRE_QUICK(d);
                if (wrch) {
                        CHN_LOCK(wrch);
                        ret = chn_setspeed(wrch, *arg_i);
                        tmp = wrch->speed;
                        CHN_UNLOCK(wrch);
                }
                if (rdch && ret == 0) {
                        CHN_LOCK(rdch);
                        ret = chn_setspeed(rdch, *arg_i);
                        if (tmp == 0)
                                tmp = rdch->speed;
                        CHN_UNLOCK(rdch);
                }
                PCM_RELEASE_QUICK(d);
                *arg_i = tmp;
                break;

        case SOUND_PCM_READ_RATE:
                chn = wrch ? wrch : rdch;
                if (chn) {
                        CHN_LOCK(chn);
                        *arg_i = chn->speed;
                        CHN_UNLOCK(chn);
                } else {
                        *arg_i = 0;
                        ret = EINVAL;
                }
                break;

        case SNDCTL_DSP_STEREO:
                tmp = -1;
                *arg_i = (*arg_i)? 2 : 1;
                PCM_ACQUIRE_QUICK(d);
                if (wrch) {
                        CHN_LOCK(wrch);
                        ret = chn_setformat(wrch,
                            SND_FORMAT(wrch->format, *arg_i, 0));
                        tmp = (AFMT_CHANNEL(wrch->format) > 1)? 1 : 0;
                        CHN_UNLOCK(wrch);
                }
                if (rdch && ret == 0) {
                        CHN_LOCK(rdch);
                        ret = chn_setformat(rdch,
                            SND_FORMAT(rdch->format, *arg_i, 0));
                        if (tmp == -1)
                                tmp = (AFMT_CHANNEL(rdch->format) > 1)? 1 : 0;
                        CHN_UNLOCK(rdch);
                }
                PCM_RELEASE_QUICK(d);
                *arg_i = tmp;
                break;

        case SOUND_PCM_WRITE_CHANNELS:
/*      case SNDCTL_DSP_CHANNELS: ( == SOUND_PCM_WRITE_CHANNELS) */
                if (*arg_i < 0 || *arg_i > AFMT_CHANNEL_MAX) {
                        *arg_i = 0;
                        ret = EINVAL;
                        break;
                }
                if (*arg_i != 0) {
                        uint32_t ext = 0;

                        tmp = 0;
                        /*
                         * Map channel number to surround sound formats.
                         * Devices that need bitperfect mode to operate
                         * (e.g. more than SND_CHN_MAX channels) are not
                         * subject to any mapping.
                         */
                        if (!(pcm_getflags(d->dev) & SD_F_BITPERFECT)) {
                                struct pcmchan_matrix *m;

                                if (*arg_i > SND_CHN_MAX)
                                        *arg_i = SND_CHN_MAX;

                                m = feeder_matrix_default_channel_map(*arg_i);
                                if (m != NULL)
                                        ext = m->ext;
                        }

                        PCM_ACQUIRE_QUICK(d);
                        if (wrch) {
                                CHN_LOCK(wrch);
                                ret = chn_setformat(wrch,
                                    SND_FORMAT(wrch->format, *arg_i, ext));
                                tmp = AFMT_CHANNEL(wrch->format);
                                CHN_UNLOCK(wrch);
                        }
                        if (rdch && ret == 0) {
                                CHN_LOCK(rdch);
                                ret = chn_setformat(rdch,
                                    SND_FORMAT(rdch->format, *arg_i, ext));
                                if (tmp == 0)
                                        tmp = AFMT_CHANNEL(rdch->format);
                                CHN_UNLOCK(rdch);
                        }
                        PCM_RELEASE_QUICK(d);
                        *arg_i = tmp;
                } else {
                        chn = wrch ? wrch : rdch;
                        CHN_LOCK(chn);
                        *arg_i = AFMT_CHANNEL(chn->format);
                        CHN_UNLOCK(chn);
                }
                break;

        case SOUND_PCM_READ_CHANNELS:
                chn = wrch ? wrch : rdch;
                if (chn) {
                        CHN_LOCK(chn);
                        *arg_i = AFMT_CHANNEL(chn->format);
                        CHN_UNLOCK(chn);
                } else {
                        *arg_i = 0;
                        ret = EINVAL;
                }
                break;

        case SNDCTL_DSP_GETFMTS:        /* returns a mask of supported fmts */
                chn = wrch ? wrch : rdch;
                if (chn) {
                        CHN_LOCK(chn);
                        *arg_i = chn_getformats(chn);
                        CHN_UNLOCK(chn);
                } else {
                        *arg_i = 0;
                        ret = EINVAL;
                }
                break;

        case SNDCTL_DSP_SETFMT: /* sets _one_ format */
                if (*arg_i != AFMT_QUERY) {
                        tmp = 0;
                        PCM_ACQUIRE_QUICK(d);
                        if (wrch) {
                                CHN_LOCK(wrch);
                                ret = chn_setformat(wrch, SND_FORMAT(*arg_i,
                                    AFMT_CHANNEL(wrch->format),
                                    AFMT_EXTCHANNEL(wrch->format)));
                                tmp = wrch->format;
                                CHN_UNLOCK(wrch);
                        }
                        if (rdch && ret == 0) {
                                CHN_LOCK(rdch);
                                ret = chn_setformat(rdch, SND_FORMAT(*arg_i,
                                    AFMT_CHANNEL(rdch->format),
                                    AFMT_EXTCHANNEL(rdch->format)));
                                if (tmp == 0)
                                        tmp = rdch->format;
                                CHN_UNLOCK(rdch);
                        }
                        PCM_RELEASE_QUICK(d);
                        *arg_i = AFMT_ENCODING(tmp);
                } else {
                        chn = wrch ? wrch : rdch;
                        CHN_LOCK(chn);
                        *arg_i = AFMT_ENCODING(chn->format);
                        CHN_UNLOCK(chn);
                }
                break;

        case SNDCTL_DSP_SETFRAGMENT:
                DEB(printf("SNDCTL_DSP_SETFRAGMENT 0x%08x\n", *(int *)arg));
                {
                        uint32_t fragln = (*arg_i) & 0x0000ffff;
                        uint32_t maxfrags = ((*arg_i) & 0xffff0000) >> 16;
                        uint32_t fragsz;
                        uint32_t r_maxfrags, r_fragsz;

                        RANGE(fragln, 4, 16);
                        fragsz = 1 << fragln;

                        if (maxfrags == 0)
                                maxfrags = CHN_2NDBUFMAXSIZE / fragsz;
                        if (maxfrags < 2)
                                maxfrags = 2;
                        if (maxfrags * fragsz > CHN_2NDBUFMAXSIZE)
                                maxfrags = CHN_2NDBUFMAXSIZE / fragsz;

                        DEB(printf("SNDCTL_DSP_SETFRAGMENT %d frags, %d sz\n", maxfrags, fragsz));
                        PCM_ACQUIRE_QUICK(d);
                        if (rdch) {
                                CHN_LOCK(rdch);
                                ret = chn_setblocksize(rdch, maxfrags, fragsz);
                                r_maxfrags = rdch->bufsoft->blkcnt;
                                r_fragsz = rdch->bufsoft->blksz;
                                CHN_UNLOCK(rdch);
                        } else {
                                r_maxfrags = maxfrags;
                                r_fragsz = fragsz;
                        }
                        if (wrch && ret == 0) {
                                CHN_LOCK(wrch);
                                ret = chn_setblocksize(wrch, maxfrags, fragsz);
                                maxfrags = wrch->bufsoft->blkcnt;
                                fragsz = wrch->bufsoft->blksz;
                                CHN_UNLOCK(wrch);
                        } else { /* use whatever came from the read channel */
                                maxfrags = r_maxfrags;
                                fragsz = r_fragsz;
                        }
                        PCM_RELEASE_QUICK(d);

                        fragln = 0;
                        while (fragsz > 1) {
                                fragln++;
                                fragsz >>= 1;
                        }
                        *arg_i = (maxfrags << 16) | fragln;
                }
                break;

        case SNDCTL_DSP_GETISPACE:
                /* return the size of data available in the input queue */
                {
                        audio_buf_info *a = (audio_buf_info *)arg;
                        if (rdch) {
                                struct snd_dbuf *bs = rdch->bufsoft;

                                CHN_LOCK(rdch);
                                a->bytes = sndbuf_getready(bs);
                                a->fragments = a->bytes / bs->blksz;
                                a->fragstotal = bs->blkcnt;
                                a->fragsize = bs->blksz;
                                CHN_UNLOCK(rdch);
                        } else
                                ret = EINVAL;
                }
                break;

        case SNDCTL_DSP_GETOSPACE:
                /* return space available in the output queue */
                {
                        audio_buf_info *a = (audio_buf_info *)arg;
                        if (wrch) {
                                struct snd_dbuf *bs = wrch->bufsoft;

                                CHN_LOCK(wrch);
                                a->bytes = sndbuf_getfree(bs);
                                a->fragments = a->bytes / bs->blksz;
                                a->fragstotal = bs->blkcnt;
                                a->fragsize = bs->blksz;
                                CHN_UNLOCK(wrch);
                        } else
                                ret = EINVAL;
                }
                break;

        case SNDCTL_DSP_GETIPTR:
                {
                        count_info *a = (count_info *)arg;
                        if (rdch) {
                                struct snd_dbuf *bs = rdch->bufsoft;

                                CHN_LOCK(rdch);
                                a->bytes = bs->total;
                                a->blocks = sndbuf_getblocks(bs) - rdch->blocks;
                                a->ptr = sndbuf_getfreeptr(bs);
                                rdch->blocks = sndbuf_getblocks(bs);
                                CHN_UNLOCK(rdch);
                        } else
                                ret = EINVAL;
                }
                break;

        case SNDCTL_DSP_GETOPTR:
                {
                        count_info *a = (count_info *)arg;
                        if (wrch) {
                                struct snd_dbuf *bs = wrch->bufsoft;

                                CHN_LOCK(wrch);
                                a->bytes = bs->total;
                                a->blocks = sndbuf_getblocks(bs) - wrch->blocks;
                                a->ptr = sndbuf_getreadyptr(bs);
                                wrch->blocks = sndbuf_getblocks(bs);
                                CHN_UNLOCK(wrch);
                        } else
                                ret = EINVAL;
                }
                break;

        case SNDCTL_DSP_GETCAPS:
                PCM_LOCK(d);
                *arg_i = PCM_CAP_REALTIME | PCM_CAP_MMAP | PCM_CAP_TRIGGER;
                if (rdch && wrch && !(pcm_getflags(d->dev) & SD_F_SIMPLEX))
                        *arg_i |= PCM_CAP_DUPLEX;
                if (rdch && (rdch->flags & CHN_F_VIRTUAL) != 0)
                        *arg_i |= PCM_CAP_VIRTUAL;
                if (wrch && (wrch->flags & CHN_F_VIRTUAL) != 0)
                        *arg_i |= PCM_CAP_VIRTUAL;
                PCM_UNLOCK(d);
                break;

        case SOUND_PCM_READ_BITS:
                chn = wrch ? wrch : rdch;
                if (chn) {
                        CHN_LOCK(chn);
                        if (chn->format & AFMT_8BIT)
                                *arg_i = 8;
                        else if (chn->format & AFMT_16BIT)
                                *arg_i = 16;
                        else if (chn->format & AFMT_24BIT)
                                *arg_i = 24;
                        else if (chn->format & AFMT_32BIT)
                                *arg_i = 32;
                        else
                                ret = EINVAL;
                        CHN_UNLOCK(chn);
                } else {
                        *arg_i = 0;
                        ret = EINVAL;
                }
                break;

        case SNDCTL_DSP_SETTRIGGER:
                if (rdch) {
                        CHN_LOCK(rdch);
                        rdch->flags &= ~CHN_F_NOTRIGGER;
                        if (*arg_i & PCM_ENABLE_INPUT)
                                chn_start(rdch, 1);
                        else {
                                chn_abort(rdch);
                                chn_resetbuf(rdch);
                                rdch->flags |= CHN_F_NOTRIGGER;
                        }
                        CHN_UNLOCK(rdch);
                }
                if (wrch) {
                        CHN_LOCK(wrch);
                        wrch->flags &= ~CHN_F_NOTRIGGER;
                        if (*arg_i & PCM_ENABLE_OUTPUT)
                                chn_start(wrch, 1);
                        else {
                                chn_abort(wrch);
                                chn_resetbuf(wrch);
                                wrch->flags |= CHN_F_NOTRIGGER;
                        }
                        CHN_UNLOCK(wrch);
                }
                break;

        case SNDCTL_DSP_GETTRIGGER:
                *arg_i = 0;
                if (wrch) {
                        CHN_LOCK(wrch);
                        if (wrch->flags & CHN_F_TRIGGERED)
                                *arg_i |= PCM_ENABLE_OUTPUT;
                        CHN_UNLOCK(wrch);
                }
                if (rdch) {
                        CHN_LOCK(rdch);
                        if (rdch->flags & CHN_F_TRIGGERED)
                                *arg_i |= PCM_ENABLE_INPUT;
                        CHN_UNLOCK(rdch);
                }
                break;

        case SNDCTL_DSP_GETODELAY:
                if (wrch) {
                        struct snd_dbuf *bs = wrch->bufsoft;

                        CHN_LOCK(wrch);
                        *arg_i = sndbuf_getready(bs);
                        CHN_UNLOCK(wrch);
                } else
                        ret = EINVAL;
                break;

        case SNDCTL_DSP_POST:
                if (wrch) {
                        CHN_LOCK(wrch);
                        wrch->flags &= ~CHN_F_NOTRIGGER;
                        chn_start(wrch, 1);
                        CHN_UNLOCK(wrch);
                }
                break;

        case SNDCTL_DSP_SETDUPLEX:
                /*
                 * switch to full-duplex mode if card is in half-duplex
                 * mode and is able to work in full-duplex mode
                 */
                PCM_LOCK(d);
                if (rdch && wrch && (pcm_getflags(d->dev) & SD_F_SIMPLEX))
                        pcm_setflags(d->dev, pcm_getflags(d->dev)^SD_F_SIMPLEX);
                PCM_UNLOCK(d);
                break;

        /*
         * The following four ioctls are simple wrappers around mixer_ioctl
         * with no further processing.  xcmd is short for "translated
         * command".
         */
        case SNDCTL_DSP_GETRECVOL:
                if (xcmd == 0) {
                        xcmd = SOUND_MIXER_READ_RECLEV;
                        chn = rdch;
                }
                /* FALLTHROUGH */
        case SNDCTL_DSP_SETRECVOL:
                if (xcmd == 0) {
                        xcmd = SOUND_MIXER_WRITE_RECLEV;
                        chn = rdch;
                }
                /* FALLTHROUGH */
        case SNDCTL_DSP_GETPLAYVOL:
                if (xcmd == 0) {
                        xcmd = SOUND_MIXER_READ_PCM;
                        chn = wrch;
                }
                /* FALLTHROUGH */
        case SNDCTL_DSP_SETPLAYVOL:
                if (xcmd == 0) {
                        xcmd = SOUND_MIXER_WRITE_PCM;
                        chn = wrch;
                }

                ret = dsp_ioctl_channel(priv, chn, xcmd, arg);
                if (ret != -1) {
                        PCM_GIANT_EXIT(d);
                        return (ret);
                }

                if (d->mixer_dev != NULL) {
                        PCM_ACQUIRE_QUICK(d);
                        ret = mixer_ioctl_cmd(d->mixer_dev, xcmd, arg, -1, td,
                            MIXER_CMD_DIRECT);
                        PCM_RELEASE_QUICK(d);
                } else
                        ret = ENOTSUP;

                break;

        case SNDCTL_DSP_GET_RECSRC_NAMES:
        case SNDCTL_DSP_GET_RECSRC:
        case SNDCTL_DSP_SET_RECSRC:
                if (d->mixer_dev != NULL) {
                        PCM_ACQUIRE_QUICK(d);
                        ret = mixer_ioctl_cmd(d->mixer_dev, cmd, arg, -1, td,
                            MIXER_CMD_DIRECT);
                        PCM_RELEASE_QUICK(d);
                } else
                        ret = ENOTSUP;
                break;

        /*
         * The following 3 ioctls aren't very useful at the moment.  For
         * now, only a single channel is associated with a cdev (/dev/dspN
         * instance), so there's only a single output routing to use (i.e.,
         * the wrch bound to this cdev).
         */
        case SNDCTL_DSP_GET_PLAYTGT_NAMES:
                {
                        oss_mixer_enuminfo *ei;
                        ei = (oss_mixer_enuminfo *)arg;
                        ei->dev = 0;
                        ei->ctrl = 0;
                        ei->version = 0; /* static for now */
                        ei->strindex[0] = 0;

                        if (wrch != NULL) {
                                ei->nvalues = 1;
                                strlcpy(ei->strings, wrch->name,
                                        sizeof(ei->strings));
                        } else {
                                ei->nvalues = 0;
                                ei->strings[0] = '\0';
                        }
                }
                break;
        case SNDCTL_DSP_GET_PLAYTGT:
        case SNDCTL_DSP_SET_PLAYTGT:    /* yes, they are the same for now */
                /*
                 * Re: SET_PLAYTGT
                 *   OSSv4: "The value that was accepted by the device will
                 *   be returned back in the variable pointed by the
                 *   argument."
                 */
                if (wrch != NULL)
                        *arg_i = 0;
                else
                        ret = EINVAL;
                break;

        case SNDCTL_DSP_SILENCE:
        /*
         * Flush the software (pre-feed) buffer, but try to minimize playback
         * interruption.  (I.e., record unplayed samples with intent to
         * restore by SNDCTL_DSP_SKIP.) Intended for application "pause"
         * functionality.
         */
                if (wrch == NULL)
                        ret = EINVAL;
                else {
                        struct snd_dbuf *bs;
                        CHN_LOCK(wrch);
                        while (wrch->inprog != 0)
                                cv_wait(&wrch->cv, &wrch->lock);
                        bs = wrch->bufsoft;
                        if ((bs->shadbuf != NULL) && (sndbuf_getready(bs) > 0)) {
                                bs->sl = sndbuf_getready(bs);
                                sndbuf_dispose(bs, bs->shadbuf, sndbuf_getready(bs));
                                sndbuf_fillsilence(bs);
                                chn_start(wrch, 0);
                        }
                        CHN_UNLOCK(wrch);
                }
                break;

        case SNDCTL_DSP_SKIP:
        /*
         * OSSv4 docs: "This ioctl call discards all unplayed samples in the
         * playback buffer by moving the current write position immediately
         * before the point where the device is currently reading the samples."
         */
                if (wrch == NULL)
                        ret = EINVAL;
                else {
                        struct snd_dbuf *bs;
                        CHN_LOCK(wrch);
                        while (wrch->inprog != 0)
                                cv_wait(&wrch->cv, &wrch->lock);
                        bs = wrch->bufsoft;
                        if ((bs->shadbuf != NULL) && (bs->sl > 0)) {
                                sndbuf_softreset(bs);
                                sndbuf_acquire(bs, bs->shadbuf, bs->sl);
                                bs->sl = 0;
                                chn_start(wrch, 0);
                        }
                        CHN_UNLOCK(wrch);
                }
                break;

        case SNDCTL_DSP_CURRENT_OPTR:
        case SNDCTL_DSP_CURRENT_IPTR:
        /**
         * @note Changing formats resets the buffer counters, which differs
         *       from the 4Front drivers.  However, I don't expect this to be
         *       much of a problem.
         *
         * @note In a test where @c CURRENT_OPTR is called immediately after write
         *       returns, this driver is about 32K samples behind whereas
         *       4Front's is about 8K samples behind.  Should determine source
         *       of discrepancy, even if only out of curiosity.
         *
         * @todo Actually test SNDCTL_DSP_CURRENT_IPTR.
         */
                chn = (cmd == SNDCTL_DSP_CURRENT_OPTR) ? wrch : rdch;
                if (chn == NULL) 
                        ret = EINVAL;
                else {
                        struct snd_dbuf *bs;
                        /* int tmp; */

                        oss_count_t *oc = (oss_count_t *)arg;

                        CHN_LOCK(chn);
                        bs = chn->bufsoft;
                        oc->samples = bs->total / bs->align;
                        oc->fifo_samples = sndbuf_getready(bs) / bs->align;
                        CHN_UNLOCK(chn);
                }
                break;

        case SNDCTL_DSP_HALT_OUTPUT:
        case SNDCTL_DSP_HALT_INPUT:
                chn = (cmd == SNDCTL_DSP_HALT_OUTPUT) ? wrch : rdch;
                if (chn == NULL)
                        ret = EINVAL;
                else {
                        CHN_LOCK(chn);
                        chn_abort(chn);
                        CHN_UNLOCK(chn);
                }
                break;

        case SNDCTL_DSP_LOW_WATER:
        /*
         * Set the number of bytes required to attract attention by
         * select/poll.
         */
                if (wrch != NULL) {
                        CHN_LOCK(wrch);
                        wrch->lw = (*arg_i > 1) ? *arg_i : 1;
                        CHN_UNLOCK(wrch);
                }
                if (rdch != NULL) {
                        CHN_LOCK(rdch);
                        rdch->lw = (*arg_i > 1) ? *arg_i : 1;
                        CHN_UNLOCK(rdch);
                }
                break;

        case SNDCTL_DSP_GETERROR:
#ifdef COMPAT_FREEBSD32
        case SNDCTL_DSP_GETERROR32:
#endif
        /*
         * OSSv4 docs:  "All errors and counters will automatically be
         * cleared to zeroes after the call so each call will return only
         * the errors that occurred after the previous invocation. ... The
         * play_underruns and rec_overrun fields are the only useful fields
         * returned by OSS 4.0."
         */
                {
                        audio_errinfo *ei = (audio_errinfo *)arg;
#ifdef COMPAT_FREEBSD32
                        audio_errinfo errinfo;
                        audio_errinfo32 *ei32 = (audio_errinfo32 *)arg;

                        if (cmd == SNDCTL_DSP_GETERROR32) {
                                ei = &errinfo;
                        }
#endif

                        bzero((void *)ei, sizeof(*ei));

                        if (wrch != NULL) {
                                CHN_LOCK(wrch);
                                ei->play_underruns = wrch->xruns;
                                wrch->xruns = 0;
                                CHN_UNLOCK(wrch);
                        }
                        if (rdch != NULL) {
                                CHN_LOCK(rdch);
                                ei->rec_overruns = rdch->xruns;
                                rdch->xruns = 0;
                                CHN_UNLOCK(rdch);
                        }
#ifdef COMPAT_FREEBSD32
                        if (cmd == SNDCTL_DSP_GETERROR32) {
                                bzero((void *)ei32, sizeof(*ei32));
                                ei32->play_underruns = ei->play_underruns;
                                ei32->rec_overruns = ei->rec_overruns;
                                ei32->play_ptradjust = ei->play_ptradjust;
                                ei32->rec_ptradjust = ei->rec_ptradjust;
                                ei32->play_errorcount = ei->play_errorcount;
                                ei32->rec_errorcount = ei->rec_errorcount;
                                ei32->play_lasterror = ei->play_lasterror;
                                ei32->rec_lasterror = ei->rec_lasterror;
                                ei32->play_errorparm = ei->play_errorparm;
                                ei32->rec_errorparm = ei->rec_errorparm;
                        }
#endif
                }
                break;

        case SNDCTL_DSP_SYNCGROUP:
                PCM_ACQUIRE_QUICK(d);
                ret = dsp_oss_syncgroup(wrch, rdch, (oss_syncgroup *)arg);
                PCM_RELEASE_QUICK(d);
                break;

        case SNDCTL_DSP_SYNCSTART:
                PCM_ACQUIRE_QUICK(d);
                ret = dsp_oss_syncstart(*arg_i);
                PCM_RELEASE_QUICK(d);
                break;

        case SNDCTL_DSP_POLICY:
                PCM_ACQUIRE_QUICK(d);
                ret = dsp_oss_policy(wrch, rdch, *arg_i);
                PCM_RELEASE_QUICK(d);
                break;

        case SNDCTL_DSP_COOKEDMODE:
                PCM_ACQUIRE_QUICK(d);
                if (!(pcm_getflags(d->dev) & SD_F_BITPERFECT))
                        ret = dsp_oss_cookedmode(wrch, rdch, *arg_i);
                PCM_RELEASE_QUICK(d);
                break;
        case SNDCTL_DSP_GET_CHNORDER:
                PCM_ACQUIRE_QUICK(d);
                ret = dsp_oss_getchnorder(wrch, rdch, (unsigned long long *)arg);
                PCM_RELEASE_QUICK(d);
                break;
        case SNDCTL_DSP_SET_CHNORDER:
                PCM_ACQUIRE_QUICK(d);
                ret = dsp_oss_setchnorder(wrch, rdch, (unsigned long long *)arg);
                PCM_RELEASE_QUICK(d);
                break;
        case SNDCTL_DSP_GETCHANNELMASK:         /* XXX vlc */
                PCM_ACQUIRE_QUICK(d);
                ret = dsp_oss_getchannelmask(wrch, rdch, (int *)arg);
                PCM_RELEASE_QUICK(d);
                break;
        case SNDCTL_DSP_BIND_CHANNEL:           /* XXX what?!? */
                ret = EINVAL;
                break;
#ifdef  OSSV4_EXPERIMENT
        /*
         * XXX The following ioctls are not yet supported and just return
         * EINVAL.
         */
        case SNDCTL_DSP_GETOPEAKS:
        case SNDCTL_DSP_GETIPEAKS:
                chn = (cmd == SNDCTL_DSP_GETOPEAKS) ? wrch : rdch;
                if (chn == NULL)
                        ret = EINVAL;
                else {
                        oss_peaks_t *op = (oss_peaks_t *)arg;
                        int lpeak, rpeak;

                        CHN_LOCK(chn);
                        ret = chn_getpeaks(chn, &lpeak, &rpeak);
                        if (ret == -1)
                                ret = EINVAL;
                        else {
                                (*op)[0] = lpeak;
                                (*op)[1] = rpeak;
                        }
                        CHN_UNLOCK(chn);
                }
                break;

        /*
         * XXX Once implemented, revisit this for proper cv protection
         *     (if necessary).
         */
        case SNDCTL_GETLABEL:
                ret = dsp_oss_getlabel(wrch, rdch, (oss_label_t *)arg);
                break;
        case SNDCTL_SETLABEL:
                ret = dsp_oss_setlabel(wrch, rdch, (oss_label_t *)arg);
                break;
        case SNDCTL_GETSONG:
                ret = dsp_oss_getsong(wrch, rdch, (oss_longname_t *)arg);
                break;
        case SNDCTL_SETSONG:
                ret = dsp_oss_setsong(wrch, rdch, (oss_longname_t *)arg);
                break;
        case SNDCTL_SETNAME:
                ret = dsp_oss_setname(wrch, rdch, (oss_longname_t *)arg);
                break;
#endif  /* !OSSV4_EXPERIMENT */
        case SNDCTL_DSP_MAPINBUF:
        case SNDCTL_DSP_MAPOUTBUF:
        case SNDCTL_DSP_SETSYNCRO:
                /* undocumented */

        case SNDCTL_DSP_SUBDIVIDE:
        case SOUND_PCM_WRITE_FILTER:
        case SOUND_PCM_READ_FILTER:
                /* dunno what these do, don't sound important */

        default:
                DEB(printf("default ioctl fn 0x%08lx fail\n", cmd));
                ret = EINVAL;
                break;
        }

        PCM_GIANT_LEAVE(d);

        return (ret);
}

static int
dsp_poll(struct cdev *i_dev, int events, struct thread *td)
{
        struct dsp_cdevpriv *priv;
        struct snddev_info *d;
        struct pcm_channel *wrch, *rdch;
        int ret, e, err;

        if ((err = devfs_get_cdevpriv((void **)&priv)) != 0)
                return (err);
        d = priv->sc;
        if (!DSP_REGISTERED(d)) {
                /* XXX many clients don't understand POLLNVAL */
                return (events & (POLLHUP | POLLPRI | POLLIN |
                    POLLRDNORM | POLLOUT | POLLWRNORM));
        }
        PCM_GIANT_ENTER(d);

        ret = 0;

        dsp_lock_chans(priv, FREAD | FWRITE);
        wrch = priv->wrch;
        rdch = priv->rdch;

        if (wrch != NULL && !(wrch->flags & CHN_F_DEAD)) {
                e = (events & (POLLOUT | POLLWRNORM));
                if (e)
                        ret |= chn_poll(wrch, e, td);
        }

        if (rdch != NULL && !(rdch->flags & CHN_F_DEAD)) {
                e = (events & (POLLIN | POLLRDNORM));
                if (e)
                        ret |= chn_poll(rdch, e, td);
        }

        dsp_unlock_chans(priv, FREAD | FWRITE);

        PCM_GIANT_LEAVE(d);

        return (ret);
}

static int
dsp_mmap(struct cdev *i_dev, vm_ooffset_t offset, vm_paddr_t *paddr,
    int nprot, vm_memattr_t *memattr)
{

        /*
         * offset is in range due to checks in dsp_mmap_single().
         * XXX memattr is not honored.
         */
        *paddr = vtophys(offset);
        return (0);
}

static int
dsp_mmap_single(struct cdev *i_dev, vm_ooffset_t *offset,
    vm_size_t size, struct vm_object **object, int nprot)
{
        struct dsp_cdevpriv *priv;
        struct snddev_info *d;
        struct pcm_channel *wrch, *rdch, *c;
        int err;

        /*
         * Reject PROT_EXEC by default. It just doesn't makes sense.
         * Unfortunately, we have to give up this one due to linux_mmap
         * changes.
         *
         * https://lists.freebsd.org/pipermail/freebsd-emulation/2007-June/003698.html
         *
         */
#ifdef SV_ABI_LINUX
        if ((nprot & PROT_EXEC) && (dsp_mmap_allow_prot_exec < 0 ||
            (dsp_mmap_allow_prot_exec == 0 &&
            SV_CURPROC_ABI() != SV_ABI_LINUX)))
#else
        if ((nprot & PROT_EXEC) && dsp_mmap_allow_prot_exec < 1)
#endif
                return (EINVAL);

        /*
         * PROT_READ (alone) selects the input buffer.
         * PROT_WRITE (alone) selects the output buffer.
         * PROT_WRITE|PROT_READ together select the output buffer.
         */
        if ((nprot & (PROT_READ | PROT_WRITE)) == 0)
                return (EINVAL);

        if ((err = devfs_get_cdevpriv((void **)&priv)) != 0)
                return (err);
        d = priv->sc;
        if (!DSP_REGISTERED(d))
                return (EINVAL);

        PCM_GIANT_ENTER(d);

        dsp_lock_chans(priv, FREAD | FWRITE);
        wrch = priv->wrch;
        rdch = priv->rdch;

        c = ((nprot & PROT_WRITE) != 0) ? wrch : rdch;
        if (c == NULL || (c->flags & CHN_F_MMAP_INVALID) ||
            (*offset  + size) > c->bufsoft->allocsize ||
            (wrch != NULL && (wrch->flags & CHN_F_MMAP_INVALID)) ||
            (rdch != NULL && (rdch->flags & CHN_F_MMAP_INVALID))) {
                dsp_unlock_chans(priv, FREAD | FWRITE);
                PCM_GIANT_EXIT(d);
                return (EINVAL);
        }

        if (wrch != NULL)
                wrch->flags |= CHN_F_MMAP;
        if (rdch != NULL)
                rdch->flags |= CHN_F_MMAP;

        *offset = (uintptr_t)sndbuf_getbufofs(c->bufsoft, *offset);
        dsp_unlock_chans(priv, FREAD | FWRITE);
        *object = vm_pager_allocate(OBJT_DEVICE, i_dev,
            size, nprot, *offset, curthread->td_ucred);

        PCM_GIANT_LEAVE(d);

        if (*object == NULL)
                 return (EINVAL);
        return (0);
}

static const char *dsp_aliases[] = {
        "dsp_ac3",
        "dsp_mmap",
        "dsp_multich",
        "dsp_spdifout",
        "dsp_spdifin",
};

static void
dsp_clone(void *arg, struct ucred *cred, char *name, int namelen,
    struct cdev **dev)
{
        struct snddev_info *d;
        size_t i;

        if (*dev != NULL)
                return;
        if (strcmp(name, "dsp") == 0 && dsp_basename_clone)
                goto found;
        for (i = 0; i < nitems(dsp_aliases); i++) {
                if (strcmp(name, dsp_aliases[i]) == 0)
                        goto found;
        }
        return;
found:
        bus_topo_lock();
        d = devclass_get_softc(pcm_devclass, snd_unit);
        /*
         * If we only have a single soundcard attached and we detach it right
         * before entering dsp_clone(), there is a chance pcm_unregister() will
         * have returned already, meaning it will have set snd_unit to -1, and
         * thus devclass_get_softc() will return NULL here.
         */
        if (DSP_REGISTERED(d)) {
                *dev = d->dsp_dev;
                dev_ref(*dev);
        }
        bus_topo_unlock();
}

static void
dsp_sysinit(void *p)
{
        if (dsp_ehtag != NULL)
                return;
        dsp_ehtag = EVENTHANDLER_REGISTER(dev_clone, dsp_clone, 0, 1000);
}

static void
dsp_sysuninit(void *p)
{
        if (dsp_ehtag == NULL)
                return;
        EVENTHANDLER_DEREGISTER(dev_clone, dsp_ehtag);
        dsp_ehtag = NULL;
}

SYSINIT(dsp_sysinit, SI_SUB_DRIVERS, SI_ORDER_MIDDLE, dsp_sysinit, NULL);
SYSUNINIT(dsp_sysuninit, SI_SUB_DRIVERS, SI_ORDER_MIDDLE, dsp_sysuninit, NULL);

static void
dsp_oss_audioinfo_unavail(oss_audioinfo *ai, int unit)
{
        bzero(ai, sizeof(*ai));
        ai->dev = unit;
        snprintf(ai->name, sizeof(ai->name), "pcm%d (unavailable)", unit);
        ai->pid = -1;
        strlcpy(ai->cmd, CHN_COMM_UNUSED, sizeof(ai->cmd));
        ai->card_number = unit;
        ai->port_number = unit;
        ai->mixer_dev = -1;
        ai->legacy_device = unit;
}

/**
 * @brief Handler for SNDCTL_AUDIOINFO.
 *
 * Gathers information about the audio device specified in ai->dev.  If
 * ai->dev == -1, then this function gathers information about the current
 * device.  If the call comes in on a non-audio device and ai->dev == -1,
 * return EINVAL.
 *
 * This routine is supposed to go practically straight to the hardware,
 * getting capabilities directly from the sound card driver, side-stepping
 * the intermediate channel interface.
 *
 * @note
 * Calling threads must not hold any snddev_info or pcm_channel locks.
 *
 * @param dev           device on which the ioctl was issued
 * @param ai            ioctl request data container
 * @param ex            flag to distinguish between SNDCTL_AUDIOINFO from
 *                      SNDCTL_AUDIOINFO_EX
 *
 * @retval 0            success
 * @retval EINVAL       ai->dev specifies an invalid device
 */
int
dsp_oss_audioinfo(struct cdev *i_dev, oss_audioinfo *ai, bool ex)
{
        struct pcmchan_caps *caps;
        struct pcm_channel *ch;
        struct snddev_info *d;
        uint32_t fmts;
        int i, minch, maxch, unit;

        /*
         * If probing the device that received the ioctl, make sure it's a
         * DSP device.  (Users may use this ioctl with /dev/mixer and
         * /dev/midi.)
         */
        if (ai->dev == -1 && i_dev->si_devsw != &dsp_cdevsw)
                return (EINVAL);

        bus_topo_lock();
        for (unit = 0; pcm_devclass != NULL &&
            unit < devclass_get_maxunit(pcm_devclass); unit++) {
                d = devclass_get_softc(pcm_devclass, unit);
                if (!PCM_REGISTERED(d)) {
                        if ((ai->dev == -1 && unit == snd_unit) ||
                            ai->dev == unit) {
                                dsp_oss_audioinfo_unavail(ai, unit);
                                bus_topo_unlock();
                                return (0);
                        } else {
                                d = NULL;
                                continue;
                        }
                }

                PCM_UNLOCKASSERT(d);
                PCM_LOCK(d);
                if ((ai->dev == -1 && d->dsp_dev == i_dev) ||
                    (ai->dev == unit)) {
                        PCM_UNLOCK(d);
                        break;
                } else {
                        PCM_UNLOCK(d);
                        d = NULL;
                }
        }
        bus_topo_unlock();

        /* Exhausted the search -- nothing is locked, so return. */
        if (d == NULL)
                return (EINVAL);

        /* XXX Need Giant magic entry ??? */

        PCM_UNLOCKASSERT(d);
        PCM_LOCK(d);

        bzero((void *)ai, sizeof(oss_audioinfo));
        ai->dev = unit;
        strlcpy(ai->name, device_get_desc(d->dev), sizeof(ai->name));
        ai->pid = -1;
        strlcpy(ai->cmd, CHN_COMM_UNKNOWN, sizeof(ai->cmd));
        ai->card_number = unit;
        ai->port_number = unit;
        ai->mixer_dev = (d->mixer_dev != NULL) ? unit : -1;
        ai->legacy_device = unit;
        snprintf(ai->devnode, sizeof(ai->devnode), "/dev/dsp%d", unit);
        ai->enabled = device_is_attached(d->dev) ? 1 : 0;
        ai->next_play_engine = 0;
        ai->next_rec_engine = 0;
        ai->busy = 0;
        ai->caps = PCM_CAP_REALTIME | PCM_CAP_MMAP | PCM_CAP_TRIGGER;
        ai->iformats = 0;
        ai->oformats = 0;
        ai->min_rate = INT_MAX;
        ai->max_rate = 0;
        ai->min_channels = INT_MAX;
        ai->max_channels = 0;

        /* Gather global information about the device. */
        CHN_FOREACH(ch, d, channels.pcm) {
                CHN_UNLOCKASSERT(ch);
                CHN_LOCK(ch);

                /*
                 * Skip physical channels if we are servicing SNDCTL_AUDIOINFO,
                 * or VCHANs if we are servicing SNDCTL_AUDIOINFO_EX.
                 *
                 * For SNDCTL_AUDIOINFO do not skip the physical channels if
                 * there are no VCHANs.
                 */
                if ((ex && (ch->flags & CHN_F_VIRTUAL) != 0) ||
                    ((!ex && (ch->flags & CHN_F_VIRTUAL) == 0) &&
                    (d->pvchancount > 0 || d->rvchancount > 0))) {
                        CHN_UNLOCK(ch);
                        continue;
                }

                if ((ch->flags & CHN_F_BUSY) == 0) {
                        ai->busy |= (ch->direction == PCMDIR_PLAY) ?
                            OPEN_WRITE : OPEN_READ;
                }

                ai->caps |=
                    ((ch->flags & CHN_F_VIRTUAL) ? PCM_CAP_VIRTUAL : 0) |
                    ((ch->direction == PCMDIR_PLAY) ? PCM_CAP_OUTPUT :
                    PCM_CAP_INPUT);

                caps = chn_getcaps(ch);

                minch = INT_MAX;
                maxch = 0;
                fmts = 0;
                for (i = 0; caps->fmtlist[i]; i++) {
                        fmts |= AFMT_ENCODING(caps->fmtlist[i]);
                        minch = min(AFMT_CHANNEL(caps->fmtlist[i]), minch);
                        maxch = max(AFMT_CHANNEL(caps->fmtlist[i]), maxch);
                }

                if (ch->direction == PCMDIR_PLAY)
                        ai->oformats |= fmts;
                else
                        ai->iformats |= fmts;

                if (ex || (pcm_getflags(d->dev) & SD_F_BITPERFECT)) {
                        ai->min_rate = min(ai->min_rate, caps->minspeed);
                        ai->max_rate = max(ai->max_rate, caps->maxspeed);
                } else {
                        ai->min_rate = min(ai->min_rate, feeder_rate_min);
                        ai->max_rate = max(ai->max_rate, feeder_rate_max);
                }
                ai->min_channels = min(ai->min_channels, minch);
                ai->max_channels = max(ai->max_channels, maxch);

                CHN_UNLOCK(ch);
        }
        if (ai->min_rate == INT_MAX)
                ai->min_rate = 0;
        if (ai->min_channels == INT_MAX)
                ai->min_channels = 0;

        PCM_UNLOCK(d);

        return (0);
}

static int
dsp_oss_engineinfo_cb(void *data, void *arg)
{
        struct dsp_cdevpriv *priv = data;
        struct pcm_channel *ch = arg;

        if (DSP_REGISTERED(priv->sc) && (ch == priv->rdch || ch == priv->wrch))
                return (1);

        return (0);
}

/**
 * @brief Handler for SNDCTL_ENGINEINFO
 *
 * Gathers information about the audio device's engine specified in ai->dev.
 * If ai->dev == -1, then this function gathers information about the current
 * device.  If the call comes in on a non-audio device and ai->dev == -1,
 * return EINVAL.
 *
 * This routine is supposed to go practically straight to the hardware,
 * getting capabilities directly from the sound card driver, side-stepping
 * the intermediate channel interface.
 *
 * @note
 * Calling threads must not hold any snddev_info or pcm_channel locks.
 * 
 * @param dev           device on which the ioctl was issued
 * @param ai            ioctl request data container
 *
 * @retval 0            success
 * @retval EINVAL       ai->dev specifies an invalid device
 */
int
dsp_oss_engineinfo(struct cdev *i_dev, oss_audioinfo *ai)
{
        struct pcmchan_caps *caps;
        struct pcm_channel *ch;
        struct snddev_info *d;
        uint32_t fmts;
        int i, nchan, *rates, minch, maxch, unit;

        /*
         * If probing the device that received the ioctl, make sure it's a
         * DSP device.  (Users may use this ioctl with /dev/mixer and
         * /dev/midi.)
         */
        if (ai->dev == -1 && i_dev->si_devsw != &dsp_cdevsw)
                return (EINVAL);

        ch = NULL;
        nchan = 0;

        /*
         * Search for the requested audio device (channel).  Start by
         * iterating over pcm devices.
         */ 
        bus_topo_lock();
        for (unit = 0; pcm_devclass != NULL &&
            unit < devclass_get_maxunit(pcm_devclass); unit++) {
                d = devclass_get_softc(pcm_devclass, unit);
                if (!PCM_REGISTERED(d))
                        continue;

                /* XXX Need Giant magic entry ??? */

                /* See the note in function docblock */
                PCM_UNLOCKASSERT(d);
                PCM_LOCK(d);

                CHN_FOREACH(ch, d, channels.pcm) {
                        CHN_UNLOCKASSERT(ch);
                        CHN_LOCK(ch);
                        if ((ai->dev == -1 && devfs_foreach_cdevpriv(
                            i_dev, dsp_oss_engineinfo_cb, ch) != 0) ||
                            ai->dev == nchan)
                                break;
                        CHN_UNLOCK(ch);
                        ++nchan;
                }

                if (ch == NULL) {
                        PCM_UNLOCK(d);
                        continue;
                }

                /*
                 * At this point, the following synchronization stuff
                 * has happened:
                 * - a specific PCM device is locked.
                 * - a specific audio channel has been locked, so be
                 *   sure to unlock when exiting;
                 */

                caps = chn_getcaps(ch);

                /*
                 * With all handles collected, zero out the user's
                 * container and begin filling in its fields.
                 */
                bzero((void *)ai, sizeof(oss_audioinfo));

                ai->dev = nchan;
                strlcpy(ai->name, ch->name,  sizeof(ai->name));

                if ((ch->flags & CHN_F_BUSY) == 0)
                        ai->busy = 0;
                else
                        ai->busy = (ch->direction == PCMDIR_PLAY) ? OPEN_WRITE : OPEN_READ;

                ai->pid = ch->pid;
                strlcpy(ai->cmd, ch->comm, sizeof(ai->cmd));

                /*
                 * These flags stolen from SNDCTL_DSP_GETCAPS handler.
                 * Note, however, that a single channel operates in
                 * only one direction, so PCM_CAP_DUPLEX is out.
                 */
                /**
                 * @todo @c SNDCTL_AUDIOINFO::caps - Make drivers keep
                 *       these in pcmchan::caps?
                 */
                ai->caps = PCM_CAP_REALTIME | PCM_CAP_MMAP | PCM_CAP_TRIGGER |
                    ((ch->flags & CHN_F_VIRTUAL) ? PCM_CAP_VIRTUAL : 0) |
                    ((ch->direction == PCMDIR_PLAY) ? PCM_CAP_OUTPUT : PCM_CAP_INPUT);

                /*
                 * Collect formats supported @b natively by the
                 * device.  Also determine min/max channels.
                 */
                minch = INT_MAX;
                maxch = 0;
                fmts = 0;
                for (i = 0; caps->fmtlist[i]; i++) {
                        fmts |= AFMT_ENCODING(caps->fmtlist[i]);
                        minch = min(AFMT_CHANNEL(caps->fmtlist[i]), minch);
                        maxch = max(AFMT_CHANNEL(caps->fmtlist[i]), maxch);
                }

                if (ch->direction == PCMDIR_PLAY)
                        ai->oformats = fmts;
                else
                        ai->iformats = fmts;

                /**
                 * @note
                 * @c magic - OSSv4 docs: "Reserved for internal use
                 *    by OSS."
                 *
                 * @par
                 * @c card_number - OSSv4 docs: "Number of the sound
                 *    card where this device belongs or -1 if this
                 *    information is not available.  Applications
                 *    should normally not use this field for any
                 *    purpose."
                 */
                ai->card_number = unit;
                /**
                 * @todo @c song_name - depends first on
                 *          SNDCTL_[GS]ETSONG @todo @c label - depends
                 *          on SNDCTL_[GS]ETLABEL
                 * @todo @c port_number - routing information?
                 */
                ai->port_number = unit;
                ai->mixer_dev = (d->mixer_dev != NULL) ? unit : -1;
                /**
                 * @note
                 * @c legacy_device - OSSv4 docs:  "Obsolete."
                 */
                ai->legacy_device = unit;
                snprintf(ai->devnode, sizeof(ai->devnode), "/dev/dsp%d", unit);
                ai->enabled = device_is_attached(d->dev) ? 1 : 0;
                /**
                 * @note
                 * @c flags - OSSv4 docs: "Reserved for future use."
                 *
                 * @note
                 * @c binding - OSSv4 docs: "Reserved for future use."
                 *
                 * @todo @c handle - haven't decided how to generate
                 *       this yet; bus, vendor, device IDs?
                 */

                if ((ch->flags & CHN_F_EXCLUSIVE) ||
                    (pcm_getflags(d->dev) & SD_F_BITPERFECT)) {
                        ai->min_rate = caps->minspeed;
                        ai->max_rate = caps->maxspeed;
                } else {
                        ai->min_rate = feeder_rate_min;
                        ai->max_rate = feeder_rate_max;
                }

                ai->min_channels = minch;
                ai->max_channels = maxch;

                ai->nrates = chn_getrates(ch, &rates);
                if (ai->nrates > OSS_MAX_SAMPLE_RATES)
                        ai->nrates = OSS_MAX_SAMPLE_RATES;

                for (i = 0; i < ai->nrates; i++)
                        ai->rates[i] = rates[i];

                ai->next_play_engine = 0;
                ai->next_rec_engine = 0;

                CHN_UNLOCK(ch);
                PCM_UNLOCK(d);
                bus_topo_unlock();

                return (0);
        }
        bus_topo_unlock();

        /* Exhausted the search -- nothing is locked, so return. */
        return (EINVAL);
}

/**
 * @brief Assigns a PCM channel to a sync group.
 *
 * Sync groups are used to enable audio operations on multiple devices
 * simultaneously.  They may be used with any number of devices and may
 * span across applications.  Devices are added to groups with
 * the SNDCTL_DSP_SYNCGROUP ioctl, and operations are triggered with the
 * SNDCTL_DSP_SYNCSTART ioctl.
 *
 * If the @c id field of the @c group parameter is set to zero, then a new
 * sync group is created.  Otherwise, wrch and rdch (if set) are added to
 * the group specified.
 *
 * @todo As far as memory allocation, should we assume that things are
 *       okay and allocate with M_WAITOK before acquiring channel locks,
 *       freeing later if not?
 *
 * @param wrch  output channel associated w/ device (if any)
 * @param rdch  input channel associated w/ device (if any)
 * @param group Sync group parameters
 *
 * @retval 0            success
 * @retval non-zero     error to be propagated upstream
 */
static int
dsp_oss_syncgroup(struct pcm_channel *wrch, struct pcm_channel *rdch, oss_syncgroup *group)
{
        struct pcmchan_syncmember *smrd, *smwr;
        struct pcmchan_syncgroup *sg;
        int ret, sg_ids[3];

        smrd = NULL;
        smwr = NULL;
        sg = NULL;
        ret = 0;

        /*
         * Free_unr() may sleep, so store released syncgroup IDs until after
         * all locks are released.
         */
        sg_ids[0] = sg_ids[1] = sg_ids[2] = 0;

        PCM_SG_LOCK();

        /*
         * - Insert channel(s) into group's member list.
         * - Set CHN_F_NOTRIGGER on channel(s).
         * - Stop channel(s).  
         */

        /*
         * If device's channels are already mapped to a group, unmap them.
         */
        if (wrch) {
                CHN_LOCK(wrch);
                sg_ids[0] = chn_syncdestroy(wrch);
        }

        if (rdch) {
                CHN_LOCK(rdch);
                sg_ids[1] = chn_syncdestroy(rdch);
        }

        /*
         * Verify that mode matches character device properites.
         *  - Bail if PCM_ENABLE_OUTPUT && wrch == NULL.
         *  - Bail if PCM_ENABLE_INPUT && rdch == NULL.
         */
        if (((wrch == NULL) && (group->mode & PCM_ENABLE_OUTPUT)) ||
            ((rdch == NULL) && (group->mode & PCM_ENABLE_INPUT))) {
                ret = EINVAL;
                goto out;
        }

        /*
         * An id of zero indicates the user wants to create a new
         * syncgroup.
         */
        if (group->id == 0) {
                sg = malloc(sizeof(*sg), M_DEVBUF, M_NOWAIT);
                if (sg != NULL) {
                        SLIST_INIT(&sg->members);
                        sg->id = alloc_unr(pcmsg_unrhdr);

                        group->id = sg->id;
                        SLIST_INSERT_HEAD(&snd_pcm_syncgroups, sg, link);
                } else
                        ret = ENOMEM;
        } else {
                SLIST_FOREACH(sg, &snd_pcm_syncgroups, link) {
                        if (sg->id == group->id)
                                break;
                }
                if (sg == NULL)
                        ret = EINVAL;
        }

        /* Couldn't create or find a syncgroup.  Fail. */
        if (sg == NULL)
                goto out;

        /*
         * Allocate a syncmember, assign it and a channel together, and
         * insert into syncgroup.
         */
        if (group->mode & PCM_ENABLE_INPUT) {
                smrd = malloc(sizeof(*smrd), M_DEVBUF, M_NOWAIT);
                if (smrd == NULL) {
                        ret = ENOMEM;
                        goto out;
                }

                SLIST_INSERT_HEAD(&sg->members, smrd, link);
                smrd->parent = sg;
                smrd->ch = rdch;

                chn_abort(rdch);
                rdch->flags |= CHN_F_NOTRIGGER;
                rdch->sm = smrd;
        }

        if (group->mode & PCM_ENABLE_OUTPUT) {
                smwr = malloc(sizeof(*smwr), M_DEVBUF, M_NOWAIT);
                if (smwr == NULL) {
                        ret = ENOMEM;
                        goto out;
                }

                SLIST_INSERT_HEAD(&sg->members, smwr, link);
                smwr->parent = sg;
                smwr->ch = wrch;

                chn_abort(wrch);
                wrch->flags |= CHN_F_NOTRIGGER;
                wrch->sm = smwr;
        }

out:
        if (ret != 0) {
                free(smrd, M_DEVBUF);
                if ((sg != NULL) && SLIST_EMPTY(&sg->members)) {
                        sg_ids[2] = sg->id;
                        SLIST_REMOVE(&snd_pcm_syncgroups, sg, pcmchan_syncgroup, link);
                        free(sg, M_DEVBUF);
                }

                if (wrch)
                        wrch->sm = NULL;
                if (rdch)
                        rdch->sm = NULL;
        }

        if (wrch)
                CHN_UNLOCK(wrch);
        if (rdch)
                CHN_UNLOCK(rdch);

        PCM_SG_UNLOCK();

        if (sg_ids[0])
                free_unr(pcmsg_unrhdr, sg_ids[0]);
        if (sg_ids[1])
                free_unr(pcmsg_unrhdr, sg_ids[1]);
        if (sg_ids[2])
                free_unr(pcmsg_unrhdr, sg_ids[2]);

        return (ret);
}

/**
 * @brief Launch a sync group into action
 *
 * Sync groups are established via SNDCTL_DSP_SYNCGROUP.  This function
 * iterates over all members, triggering them along the way.
 *
 * @note Caller must not hold any channel locks.
 *
 * @param sg_id sync group identifier
 *
 * @retval 0    success
 * @retval non-zero     error worthy of propagating upstream to user
 */
static int
dsp_oss_syncstart(int sg_id)
{
        struct pcmchan_syncmember *sm, *sm_tmp;
        struct pcmchan_syncgroup *sg;
        struct pcm_channel *c;
        int ret, needlocks;

        /* Get the synclists lock */
        PCM_SG_LOCK();

        do {
                ret = 0;
                needlocks = 0;

                /* Search for syncgroup by ID */
                SLIST_FOREACH(sg, &snd_pcm_syncgroups, link) {
                        if (sg->id == sg_id)
                                break;
                }

                /* Return EINVAL if not found */
                if (sg == NULL) {
                        ret = EINVAL;
                        break;
                }

                /* Any removals resulting in an empty group should've handled this */
                KASSERT(!SLIST_EMPTY(&sg->members), ("found empty syncgroup"));

                /*
                 * Attempt to lock all member channels - if any are already
                 * locked, unlock those acquired, sleep for a bit, and try
                 * again.
                 */
                SLIST_FOREACH(sm, &sg->members, link) {
                        if (CHN_TRYLOCK(sm->ch) == 0) {
                                int timo = hz * 5/1000; 
                                if (timo < 1)
                                        timo = 1;

                                /* Release all locked channels so far, retry */
                                SLIST_FOREACH(sm_tmp, &sg->members, link) {
                                        /* sm is the member already locked */
                                        if (sm == sm_tmp)
                                                break;
                                        CHN_UNLOCK(sm_tmp->ch);
                                }

                                /** @todo Is PRIBIO correct/ */
                                ret = msleep(sm, &snd_pcm_syncgroups_mtx,
                                    PRIBIO | PCATCH, "pcmsg", timo);
                                if (ret == EINTR || ret == ERESTART)
                                        break;

                                needlocks = 1;
                                ret = 0; /* Assumes ret == EAGAIN... */
                        }
                }
        } while (needlocks && ret == 0);

        /* Proceed only if no errors encountered. */
        if (ret == 0) {
                /* Launch channels */
                while ((sm = SLIST_FIRST(&sg->members)) != NULL) {
                        SLIST_REMOVE_HEAD(&sg->members, link);

                        c = sm->ch;
                        c->sm = NULL;
                        chn_start(c, 1);
                        c->flags &= ~CHN_F_NOTRIGGER;
                        CHN_UNLOCK(c);

                        free(sm, M_DEVBUF);
                }

                SLIST_REMOVE(&snd_pcm_syncgroups, sg, pcmchan_syncgroup, link);
                free(sg, M_DEVBUF);
        }

        PCM_SG_UNLOCK();

        /*
         * Free_unr() may sleep, so be sure to give up the syncgroup lock
         * first.
         */
        if (ret == 0)
                free_unr(pcmsg_unrhdr, sg_id);

        return (ret);
}

/**
 * @brief Handler for SNDCTL_DSP_POLICY
 *
 * The SNDCTL_DSP_POLICY ioctl is a simpler interface to control fragment
 * size and count like with SNDCTL_DSP_SETFRAGMENT.  Instead of the user
 * specifying those two parameters, s/he simply selects a number from 0..10
 * which corresponds to a buffer size.  Smaller numbers request smaller
 * buffers with lower latencies (at greater overhead from more frequent
 * interrupts), while greater numbers behave in the opposite manner.
 *
 * The 4Front spec states that a value of 5 should be the default.  However,
 * this implementation deviates slightly by using a linear scale without
 * consulting drivers.  I.e., even though drivers may have different default
 * buffer sizes, a policy argument of 5 will have the same result across
 * all drivers.
 *
 * See http://manuals.opensound.com/developer/SNDCTL_DSP_POLICY.html for
 * more information.
 *
 * @todo When SNDCTL_DSP_COOKEDMODE is supported, it'll be necessary to
 *       work with hardware drivers directly.
 *
 * @note PCM channel arguments must not be locked by caller.
 *
 * @param wrch  Pointer to opened playback channel (optional; may be NULL)
 * @param rdch  " recording channel (optional; may be NULL)
 * @param policy Integer from [0:10]
 *
 * @retval 0    constant (for now)
 */
static int
dsp_oss_policy(struct pcm_channel *wrch, struct pcm_channel *rdch, int policy)
{
        int ret;

        if (policy < CHN_POLICY_MIN || policy > CHN_POLICY_MAX)
                return (EIO);

        /* Default: success */
        ret = 0;

        if (rdch) {
                CHN_LOCK(rdch);
                ret = chn_setlatency(rdch, policy);
                CHN_UNLOCK(rdch);
        }

        if (wrch && ret == 0) {
                CHN_LOCK(wrch);
                ret = chn_setlatency(wrch, policy);
                CHN_UNLOCK(wrch);
        }

        if (ret)
                ret = EIO;

        return (ret);
}

/**
 * @brief Enable or disable "cooked" mode
 *
 * This is a handler for @c SNDCTL_DSP_COOKEDMODE.  When in cooked mode, which
 * is the default, the sound system handles rate and format conversions
 * automatically (ex: user writing 11025Hz/8 bit/unsigned but card only
 * operates with 44100Hz/16bit/signed samples).
 *
 * Disabling cooked mode is intended for applications wanting to mmap()
 * a sound card's buffer space directly, bypassing the FreeBSD 2-stage
 * feeder architecture, presumably to gain as much control over audio
 * hardware as possible.
 *
 * See @c http://manuals.opensound.com/developer/SNDCTL_DSP_COOKEDMODE.html
 * for more details.
 *
 * @param wrch          playback channel (optional; may be NULL)
 * @param rdch          recording channel (optional; may be NULL)
 * @param enabled       0 = raw mode, 1 = cooked mode
 *
 * @retval EINVAL       Operation not yet supported.
 */
static int
dsp_oss_cookedmode(struct pcm_channel *wrch, struct pcm_channel *rdch, int enabled)
{

        /*
         * XXX I just don't get it. Why don't they call it
         * "BITPERFECT" ~ SNDCTL_DSP_BITPERFECT !?!?.
         * This is just plain so confusing, incoherent,
         * <insert any non-printable characters here>.
         */
        if (!(enabled == 1 || enabled == 0))
                return (EINVAL);

        /*
         * I won't give in. I'm inverting its logic here and now.
         * Brag all you want, but "BITPERFECT" should be the better
         * term here.
         */
        enabled ^= 0x00000001;

        if (wrch != NULL) {
                CHN_LOCK(wrch);
                wrch->flags &= ~CHN_F_BITPERFECT;
                wrch->flags |= (enabled != 0) ? CHN_F_BITPERFECT : 0x00000000;
                CHN_UNLOCK(wrch);
        }

        if (rdch != NULL) {
                CHN_LOCK(rdch);
                rdch->flags &= ~CHN_F_BITPERFECT;
                rdch->flags |= (enabled != 0) ? CHN_F_BITPERFECT : 0x00000000;
                CHN_UNLOCK(rdch);
        }

        return (0);
}

/**
 * @brief Retrieve channel interleaving order
 *
 * This is the handler for @c SNDCTL_DSP_GET_CHNORDER.
 *
 * See @c http://manuals.opensound.com/developer/SNDCTL_DSP_GET_CHNORDER.html
 * for more details.
 *
 * @note As the ioctl definition is still under construction, FreeBSD
 *       does not currently support SNDCTL_DSP_GET_CHNORDER.
 *
 * @param wrch  playback channel (optional; may be NULL)
 * @param rdch  recording channel (optional; may be NULL)
 * @param map   channel map (result will be stored there)
 *
 * @retval EINVAL       Operation not yet supported.
 */
static int
dsp_oss_getchnorder(struct pcm_channel *wrch, struct pcm_channel *rdch, unsigned long long *map)
{
        struct pcm_channel *ch;
        int ret;

        ch = (wrch != NULL) ? wrch : rdch;
        if (ch != NULL) {
                CHN_LOCK(ch);
                ret = chn_oss_getorder(ch, map);
                CHN_UNLOCK(ch);
        } else
                ret = EINVAL;

        return (ret);
}

/**
 * @brief Specify channel interleaving order
 *
 * This is the handler for @c SNDCTL_DSP_SET_CHNORDER.
 *
 * @note As the ioctl definition is still under construction, FreeBSD
 *       does not currently support @c SNDCTL_DSP_SET_CHNORDER.
 *
 * @param wrch  playback channel (optional; may be NULL)
 * @param rdch  recording channel (optional; may be NULL)
 * @param map   channel map
 *
 * @retval EINVAL       Operation not yet supported.
 */
static int
dsp_oss_setchnorder(struct pcm_channel *wrch, struct pcm_channel *rdch, unsigned long long *map)
{
        int ret;

        ret = 0;

        if (wrch != NULL) {
                CHN_LOCK(wrch);
                ret = chn_oss_setorder(wrch, map);
                CHN_UNLOCK(wrch);
        }

        if (ret == 0 && rdch != NULL) {
                CHN_LOCK(rdch);
                ret = chn_oss_setorder(rdch, map);
                CHN_UNLOCK(rdch);
        }

        return (ret);
}

static int
dsp_oss_getchannelmask(struct pcm_channel *wrch, struct pcm_channel *rdch,
    int *mask)
{
        struct pcm_channel *ch;
        uint32_t chnmask;
        int ret;

        chnmask = 0;
        ch = (wrch != NULL) ? wrch : rdch;

        if (ch != NULL) {
                CHN_LOCK(ch);
                ret = chn_oss_getmask(ch, &chnmask);
                CHN_UNLOCK(ch);
        } else
                ret = EINVAL;

        if (ret == 0)
                *mask = chnmask;

        return (ret);
}

static void
dsp_kqdetach(struct knote *kn)
{
        struct pcm_channel *ch = kn->kn_hook;

        if (ch == NULL)
                return;
        CHN_LOCK(ch);
        knlist_remove(&ch->bufsoft->sel.si_note, kn, 1);
        CHN_UNLOCK(ch);
}

static int
dsp_kqevent(struct knote *kn, long hint)
{
        struct pcm_channel *ch = kn->kn_hook;

        CHN_LOCKASSERT(ch);
        if (ch->flags & CHN_F_DEAD) {
                kn->kn_flags |= EV_EOF;
                return (1);
        }
        kn->kn_data = 0;
        if (chn_polltrigger(ch)) {
                if (kn->kn_filter == EVFILT_READ)
                        kn->kn_data = sndbuf_getready(ch->bufsoft);
                else
                        kn->kn_data = sndbuf_getfree(ch->bufsoft);
        }

        return (kn->kn_data > 0);
}

static const struct filterops dsp_filtops = {
        .f_isfd = 1,
        .f_detach = dsp_kqdetach,
        .f_event = dsp_kqevent,
};

static int
dsp_kqfilter(struct cdev *dev, struct knote *kn)
{
        struct dsp_cdevpriv *priv;
        struct snddev_info *d;
        struct pcm_channel *ch;
        int err = 0;

        if ((err = devfs_get_cdevpriv((void **)&priv)) != 0)
                return (err);

        d = priv->sc;
        if (!DSP_REGISTERED(d))
                return (EBADF);
        PCM_GIANT_ENTER(d);
        switch (kn->kn_filter) {
        case EVFILT_READ:
                ch = priv->rdch;
                break;
        case EVFILT_WRITE:
                ch = priv->wrch;
                break;
        default:
                kn->kn_hook = NULL;
                err = EINVAL;
                ch = NULL;
                break;
        }
        if (ch != NULL) {
                kn->kn_fop = &dsp_filtops;
                CHN_LOCK(ch);
                knlist_add(&ch->bufsoft->sel.si_note, kn, 1);
                CHN_UNLOCK(ch);
                kn->kn_hook = ch;
        } else
                err = EINVAL;
        PCM_GIANT_LEAVE(d);

        return (err);
}

#ifdef OSSV4_EXPERIMENT
/**
 * @brief Retrieve an audio device's label
 *
 * This is a handler for the @c SNDCTL_GETLABEL ioctl.
 *
 * See @c http://manuals.opensound.com/developer/SNDCTL_GETLABEL.html
 * for more details.
 *
 * From Hannu@4Front:  "For example ossxmix (just like some HW mixer
 * consoles) can show variable "labels" for certain controls. By default
 * the application name (say quake) is shown as the label but
 * applications may change the labels themselves."
 *
 * @note As the ioctl definition is still under construction, FreeBSD
 *       does not currently support @c SNDCTL_GETLABEL.
 *
 * @param wrch  playback channel (optional; may be NULL)
 * @param rdch  recording channel (optional; may be NULL)
 * @param label label gets copied here
 *
 * @retval EINVAL       Operation not yet supported.
 */
static int
dsp_oss_getlabel(struct pcm_channel *wrch, struct pcm_channel *rdch, oss_label_t *label)
{
        return (EINVAL);
}

/**
 * @brief Specify an audio device's label
 *
 * This is a handler for the @c SNDCTL_SETLABEL ioctl.  Please see the
 * comments for @c dsp_oss_getlabel immediately above.
 *
 * See @c http://manuals.opensound.com/developer/SNDCTL_GETLABEL.html
 * for more details.
 *
 * @note As the ioctl definition is still under construction, FreeBSD
 *       does not currently support SNDCTL_SETLABEL.
 *
 * @param wrch  playback channel (optional; may be NULL)
 * @param rdch  recording channel (optional; may be NULL)
 * @param label label gets copied from here
 *
 * @retval EINVAL       Operation not yet supported.
 */
static int
dsp_oss_setlabel(struct pcm_channel *wrch, struct pcm_channel *rdch, oss_label_t *label)
{
        return (EINVAL);
}

/**
 * @brief Retrieve name of currently played song
 *
 * This is a handler for the @c SNDCTL_GETSONG ioctl.  Audio players could
 * tell the system the name of the currently playing song, which would be
 * visible in @c /dev/sndstat.
 *
 * See @c http://manuals.opensound.com/developer/SNDCTL_GETSONG.html
 * for more details.
 *
 * @note As the ioctl definition is still under construction, FreeBSD
 *       does not currently support SNDCTL_GETSONG.
 *
 * @param wrch  playback channel (optional; may be NULL)
 * @param rdch  recording channel (optional; may be NULL)
 * @param song  song name gets copied here
 *
 * @retval EINVAL       Operation not yet supported.
 */
static int
dsp_oss_getsong(struct pcm_channel *wrch, struct pcm_channel *rdch, oss_longname_t *song)
{
        return (EINVAL);
}

/**
 * @brief Retrieve name of currently played song
 *
 * This is a handler for the @c SNDCTL_SETSONG ioctl.  Audio players could
 * tell the system the name of the currently playing song, which would be
 * visible in @c /dev/sndstat.
 *
 * See @c http://manuals.opensound.com/developer/SNDCTL_SETSONG.html
 * for more details.
 *
 * @note As the ioctl definition is still under construction, FreeBSD
 *       does not currently support SNDCTL_SETSONG.
 *
 * @param wrch  playback channel (optional; may be NULL)
 * @param rdch  recording channel (optional; may be NULL)
 * @param song  song name gets copied from here
 *
 * @retval EINVAL       Operation not yet supported.
 */
static int
dsp_oss_setsong(struct pcm_channel *wrch, struct pcm_channel *rdch, oss_longname_t *song)
{
        return (EINVAL);
}

/**
 * @brief Rename a device
 *
 * This is a handler for the @c SNDCTL_SETNAME ioctl.
 *
 * See @c http://manuals.opensound.com/developer/SNDCTL_SETNAME.html for
 * more details.
 *
 * From Hannu@4Front:  "This call is used to change the device name
 * reported in /dev/sndstat and ossinfo. So instead of  using some generic
 * 'OSS loopback audio (MIDI) driver' the device may be given a meaningfull
 * name depending on the current context (for example 'OSS virtual wave table
 * synth' or 'VoIP link to London')."
 *
 * @note As the ioctl definition is still under construction, FreeBSD
 *       does not currently support SNDCTL_SETNAME.
 *
 * @param wrch  playback channel (optional; may be NULL)
 * @param rdch  recording channel (optional; may be NULL)
 * @param name  new device name gets copied from here
 *
 * @retval EINVAL       Operation not yet supported.
 */
static int
dsp_oss_setname(struct pcm_channel *wrch, struct pcm_channel *rdch, oss_longname_t *name)
{
        return (EINVAL);
}
#endif  /* !OSSV4_EXPERIMENT */