/*-
 * 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>
 * Copyright (c) 1997 Luigi Rizzo
 * All rights reserved.
 *
 * 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/ac97.h>
#include <dev/sound/pcm/vchan.h>
#include <dev/sound/pcm/dsp.h>
#include <dev/sound/pcm/sndstat.h>
#include <dev/sound/version.h>
#include <sys/devfs.h>
#include <sys/limits.h>
#include <sys/sysctl.h>

#include "feeder_if.h"

SND_DECLARE_FILE("$FreeBSD: head/sys/dev/sound/pcm/sound.c 274035 2014-11-03 11:11:45Z bapt $");

devclass_t pcm_devclass;

int pcm_veto_load = 1;
struct cdev *default_dsp;
struct cdev *default_mixer;

int snd_unit = -1;
TUNABLE_INT("hw.snd.default_unit", &snd_unit);

static int snd_unit_auto = -1;
TUNABLE_INT("hw.snd.default_auto", &snd_unit_auto);
SYSCTL_INT(_hw_snd, OID_AUTO, default_auto, CTLFLAG_RW,
    &snd_unit_auto, 0, "assign default unit to a newly attached device");

int snd_maxautovchans = 16;
/* XXX: a tunable implies that we may need more than one sound channel before
   the system can change a sysctl (/etc/sysctl.conf), do we really need
   this? */
TUNABLE_INT("hw.snd.maxautovchans", &snd_maxautovchans);

SYSCTL_NODE(_hw, OID_AUTO, snd, CTLFLAG_RD, 0, "Sound driver");

/*
 * XXX I've had enough with people not telling proper version/arch
 *     while reporting problems, not after 387397913213th questions/requests.
 */
static char snd_driver_version[] =
    __XSTRING(SND_DRV_VERSION)"/"MACHINE_ARCH;
SYSCTL_STRING(_hw_snd, OID_AUTO, version, CTLFLAG_RD, &snd_driver_version,
    0, "driver version/arch");

/**
 * @brief Unit number allocator for syncgroup IDs
 */
struct unrhdr *pcmsg_unrhdr = NULL;

static int
sndstat_prepare_pcm(SNDSTAT_PREPARE_PCM_ARGS)
{
        SNDSTAT_PREPARE_PCM_BEGIN();
        SNDSTAT_PREPARE_PCM_END();
}

void *
snd_mtxcreate(const char *desc, const char *type)
{
        struct lock *m;

        m = kmalloc(sizeof(*m), M_DEVBUF, M_WAITOK | M_ZERO);
        lockinit(m, desc, 0, LK_CANRECURSE);
        return m;
}

void
snd_mtxfree(void *m)
{
        struct lock *mtx = m;

        lockuninit(mtx);
        kfree(mtx, M_DEVBUF);
}

void
snd_mtxassert(void *m)
{
#ifdef INVARIANTS
        struct lock *lk = m;

        KKASSERT(lockstatus(lk, curthread) == LK_EXCLUSIVE);
#endif
}

int
snd_setup_intr(device_t dev, struct resource *res, int flags, driver_intr_t hand, void *param, void **cookiep)
{
        struct snddev_info *d;

        flags &= INTR_MPSAFE;
        d = device_get_softc(dev);
        if (d != NULL && (flags & INTR_MPSAFE))
                d->flags |= SD_F_MPSAFE;

        return bus_setup_intr(dev, res, flags, hand, param, cookiep, NULL);
}

static void
pcm_clonereset(struct snddev_info *d)
{
        int cmax;

        PCM_BUSYASSERT(d);

        cmax = d->playcount + d->reccount - 1;
        if (d->pvchancount > 0)
                cmax += max(d->pvchancount, snd_maxautovchans) - 1;
        if (d->rvchancount > 0)
                cmax += max(d->rvchancount, snd_maxautovchans) - 1;
        if (cmax > PCMMAXCLONE)
                cmax = PCMMAXCLONE;
        (void)snd_clone_gc(d->clones);
        (void)snd_clone_setmaxunit(d->clones, cmax);
}

int
pcm_setvchans(struct snddev_info *d, int direction, int newcnt, int num)
{
        struct pcm_channel *c, *ch, *nch;
        struct pcmchan_caps *caps;
        int i, err, vcnt;

        PCM_BUSYASSERT(d);

        if ((direction == PCMDIR_PLAY && d->playcount < 1) ||
            (direction == PCMDIR_REC && d->reccount < 1))
                return (ENODEV);

        if (!(d->flags & SD_F_AUTOVCHAN))
                return (EINVAL);

        if (newcnt < 0 || newcnt > SND_MAXVCHANS)
                return (E2BIG);

        if (direction == PCMDIR_PLAY)
                vcnt = d->pvchancount;
        else if (direction == PCMDIR_REC)
                vcnt = d->rvchancount;
        else
                return (EINVAL);

        if (newcnt > vcnt) {
                KASSERT(num == -1 ||
                    (num >= 0 && num < SND_MAXVCHANS && (newcnt - 1) == vcnt),
                    ("bogus vchan_create() request num=%d newcnt=%d vcnt=%d",
                    num, newcnt, vcnt));
                /* add new vchans - find a parent channel first */
                ch = NULL;
                CHN_FOREACH(c, d, channels.pcm) {
                        CHN_LOCK(c);
                        if (c->direction == direction &&
                            ((c->flags & CHN_F_HAS_VCHAN) || (vcnt == 0 &&
                            c->refcount < 1 &&
                            !(c->flags & (CHN_F_BUSY | CHN_F_VIRTUAL))))) {
                                /* 
                                 * Reuse hw channel with vchans already
                                 * created.
                                 */
                                if (c->flags & CHN_F_HAS_VCHAN) {
                                        ch = c;
                                        break;
                                }
                                /*
                                 * No vchans ever created, look for
                                 * channels with supported formats.
                                 */
                                caps = chn_getcaps(c);
                                if (caps == NULL) {
                                        CHN_UNLOCK(c);
                                        continue;
                                }
                                for (i = 0; caps->fmtlist[i] != 0; i++) {
                                        if (caps->fmtlist[i] & AFMT_CONVERTIBLE)
                                                break;
                                }
                                if (caps->fmtlist[i] != 0) {
                                        ch = c;
                                        break;
                                }
                        }
                        CHN_UNLOCK(c);
                }
                if (ch == NULL)
                        return (EBUSY);
                ch->flags |= CHN_F_BUSY;
                err = 0;
                while (err == 0 && newcnt > vcnt) {
                        err = vchan_create(ch, num);
                        if (err == 0)
                                vcnt++;
                        else if (err == E2BIG && newcnt > vcnt)
                                device_printf(d->dev,
                                    "%s: err=%d Maximum channel reached.\n",
                                    __func__, err);
                }
                if (vcnt == 0)
                        ch->flags &= ~CHN_F_BUSY;
                CHN_UNLOCK(ch);
                if (err != 0)
                        return (err);
                else
                        pcm_clonereset(d);
        } else if (newcnt < vcnt) {
                KASSERT(num == -1,
                    ("bogus vchan_destroy() request num=%d", num));
                CHN_FOREACH(c, d, channels.pcm) {
                        CHN_LOCK(c);
                        if (c->direction != direction ||
                            CHN_EMPTY(c, children) ||
                            !(c->flags & CHN_F_HAS_VCHAN)) {
                                CHN_UNLOCK(c);
                                continue;
                        }
                        CHN_FOREACH_SAFE(ch, c, nch, children) {
                                CHN_LOCK(ch);
                                if (vcnt == 1 && c->refcount > 0) {
                                        CHN_UNLOCK(ch);
                                        break;
                                }
                                if (!(ch->flags & CHN_F_BUSY) &&
                                    ch->refcount < 1) {
                                        err = vchan_destroy(ch);
                                        if (err == 0)
                                                vcnt--;
                                } else
                                        CHN_UNLOCK(ch);
                                if (vcnt == newcnt)
                                        break;
                        }
                        CHN_UNLOCK(c);
                        break;
                }
                pcm_clonereset(d);
        }

        return (0);
}

/* return error status and a locked channel */
int
pcm_chnalloc(struct snddev_info *d, struct pcm_channel **ch, int direction,
    pid_t pid, char *comm, int devunit)
{
        struct pcm_channel *c;
        int err, vchancount, vchan_num;

        KASSERT(d != NULL && ch != NULL && (devunit == -1 ||
            !(devunit & ~(SND_U_MASK | SND_D_MASK | SND_C_MASK))) &&
            (direction == PCMDIR_PLAY || direction == PCMDIR_REC),
            ("%s(): invalid d=%p ch=%p direction=%d pid=%d devunit=%d",
            __func__, d, ch, direction, pid, devunit));
        PCM_BUSYASSERT(d);

        /* Double check again. */
        if (devunit != -1) {
                switch (snd_unit2d(devunit)) {
                case SND_DEV_DSPHW_PLAY:
                case SND_DEV_DSPHW_VPLAY:
                        if (direction != PCMDIR_PLAY)
                                return (ENOTSUP);
                        break;
                case SND_DEV_DSPHW_REC:
                case SND_DEV_DSPHW_VREC:
                        if (direction != PCMDIR_REC)
                                return (ENOTSUP);
                        break;
                default:
                        if (!(direction == PCMDIR_PLAY ||
                            direction == PCMDIR_REC))
                                return (ENOTSUP);
                        break;
                }
        }

        *ch = NULL;
        vchan_num = 0;
        vchancount = (direction == PCMDIR_PLAY) ? d->pvchancount :
            d->rvchancount;

retry_chnalloc:
        err = ENOTSUP;
        /* scan for a free channel */
        CHN_FOREACH(c, d, channels.pcm) {
                CHN_LOCK(c);
                if (devunit == -1 && c->direction == direction &&
                    (c->flags & CHN_F_VIRTUAL)) {
                        if (vchancount < snd_maxautovchans &&
                            vchan_num < CHN_CHAN(c)) {
                                CHN_UNLOCK(c);
                                goto vchan_alloc;
                        }
                        vchan_num++;
                }
                if (c->direction == direction && !(c->flags & CHN_F_BUSY) &&
                    (devunit == -1 || devunit == -2 || c->unit == devunit)) {
                        c->flags |= CHN_F_BUSY;
                        c->pid = pid;
                        strlcpy(c->comm, (comm != NULL) ? comm :
                            CHN_COMM_UNKNOWN, sizeof(c->comm));
                        *ch = c;
                        return (0);
                } else if (c->unit == devunit) {
                        if (c->direction != direction)
                                err = ENOTSUP;
                        else if (c->flags & CHN_F_BUSY)
                                err = EBUSY;
                        else
                                err = EINVAL;
                        CHN_UNLOCK(c);
                        return (err);
                } else if ((devunit == -1 || devunit == -2) &&
                    c->direction == direction && (c->flags & CHN_F_BUSY))
                        err = EBUSY;
                CHN_UNLOCK(c);
        }

        if (devunit == -2)
                return (err);

vchan_alloc:
        /* no channel available */
        if (devunit == -1 || snd_unit2d(devunit) == SND_DEV_DSPHW_VPLAY ||
            snd_unit2d(devunit) == SND_DEV_DSPHW_VREC) {
                if (!(vchancount > 0 && vchancount < snd_maxautovchans) &&
                    (devunit == -1 || snd_unit2c(devunit) < snd_maxautovchans))
                        return (err);
                err = pcm_setvchans(d, direction, vchancount + 1,
                    (devunit == -1) ? -1 : snd_unit2c(devunit));
                if (err == 0) {
                        if (devunit == -1)
                                devunit = -2;
                        goto retry_chnalloc;
                }
        }

        return (err);
}

/* release a locked channel and unlock it */
int
pcm_chnrelease(struct pcm_channel *c)
{
        PCM_BUSYASSERT(c->parentsnddev);
        CHN_LOCKASSERT(c);

        c->flags &= ~CHN_F_BUSY;
        c->pid = -1;
        strlcpy(c->comm, CHN_COMM_UNUSED, sizeof(c->comm));
        CHN_UNLOCK(c);

        return (0);
}

int
pcm_chnref(struct pcm_channel *c, int ref)
{
        PCM_BUSYASSERT(c->parentsnddev);
        CHN_LOCKASSERT(c);

        c->refcount += ref;

        return (c->refcount);
}

int
pcm_inprog(struct snddev_info *d, int delta)
{
        PCM_LOCKASSERT(d);

        d->inprog += delta;

        return (d->inprog);
}

static void
pcm_setmaxautovchans(struct snddev_info *d, int num)
{
        PCM_BUSYASSERT(d);

        if (num < 0)
                return;

        if (num >= 0 && d->pvchancount > num)
                (void)pcm_setvchans(d, PCMDIR_PLAY, num, -1);
        else if (num > 0 && d->pvchancount == 0)
                (void)pcm_setvchans(d, PCMDIR_PLAY, 1, -1);

        if (num >= 0 && d->rvchancount > num)
                (void)pcm_setvchans(d, PCMDIR_REC, num, -1);
        else if (num > 0 && d->rvchancount == 0)
                (void)pcm_setvchans(d, PCMDIR_REC, 1, -1);

        pcm_clonereset(d);
}

static int
sysctl_hw_snd_default_unit(SYSCTL_HANDLER_ARGS)
{
        struct snddev_info *d;
        int error, unit;

        unit = snd_unit;
        error = sysctl_handle_int(oidp, &unit, 0, req);
        if (error == 0 && req->newptr != NULL) {
                d = devclass_get_softc(pcm_devclass, unit);
                if (!PCM_REGISTERED(d) || CHN_EMPTY(d, channels.pcm))
                        return EINVAL;
                snd_unit = unit;
                snd_unit_auto = 0;
        }
        return (error);
}

/* XXX: do we need a way to let the user change the default unit? */
SYSCTL_PROC(_hw_snd, OID_AUTO, default_unit,
            CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_ANYBODY,
            0, sizeof(int), sysctl_hw_snd_default_unit, "I",
            "default sound device");

static int
sysctl_hw_snd_maxautovchans(SYSCTL_HANDLER_ARGS)
{
        struct snddev_info *d;
        int i, v, error;

        v = snd_maxautovchans;
        error = sysctl_handle_int(oidp, &v, 0, req);
        if (error == 0 && req->newptr != NULL) {
                if (v < 0)
                        v = 0;
                if (v > SND_MAXVCHANS)
                        v = SND_MAXVCHANS;
                snd_maxautovchans = v;
                for (i = 0; pcm_devclass != NULL &&
                    i < devclass_get_maxunit(pcm_devclass); i++) {
                        d = devclass_get_softc(pcm_devclass, i);
                        if (!PCM_REGISTERED(d))
                                continue;
                        PCM_ACQUIRE_QUICK(d);
                        pcm_setmaxautovchans(d, v);
                        PCM_RELEASE_QUICK(d);
                }
        }
        return (error);
}
SYSCTL_PROC(_hw_snd, OID_AUTO, maxautovchans, CTLTYPE_INT | CTLFLAG_RW,
            0, sizeof(int), sysctl_hw_snd_maxautovchans, "I", "maximum virtual channel");

struct pcm_channel *
pcm_chn_create(struct snddev_info *d, struct pcm_channel *parent, kobj_class_t cls, int dir, int num, void *devinfo)
{
        struct pcm_channel *ch;
        int direction, err, rpnum, *pnum, max;
        int udc, device, chan;
        char *dirs, *devname, buf[CHN_NAMELEN];

        PCM_BUSYASSERT(d);
        PCM_LOCKASSERT(d);
        KASSERT(num >= -1, ("invalid num=%d", num));


        switch (dir) {
        case PCMDIR_PLAY:
                dirs = "play";
                direction = PCMDIR_PLAY;
                pnum = &d->playcount;
                device = SND_DEV_DSPHW_PLAY;
                max = SND_MAXHWCHAN;
                break;
        case PCMDIR_PLAY_VIRTUAL:
                dirs = "virtual";
                direction = PCMDIR_PLAY;
                pnum = &d->pvchancount;
                device = SND_DEV_DSPHW_VPLAY;
                max = SND_MAXVCHANS;
                break;
        case PCMDIR_REC:
                dirs = "record";
                direction = PCMDIR_REC;
                pnum = &d->reccount;
                device = SND_DEV_DSPHW_REC;
                max = SND_MAXHWCHAN;
                break;
        case PCMDIR_REC_VIRTUAL:
                dirs = "virtual";
                direction = PCMDIR_REC;
                pnum = &d->rvchancount;
                device = SND_DEV_DSPHW_VREC;
                max = SND_MAXVCHANS;
                break;
        default:
                return (NULL);
        }

        chan = (num == -1) ? 0 : num;

        if (*pnum >= max || chan >= max)
                return (NULL);

        rpnum = 0;

        CHN_FOREACH(ch, d, channels.pcm) {
                if (CHN_DEV(ch) != device)
                        continue;
                if (chan == CHN_CHAN(ch)) {
                        if (num != -1) {
                                device_printf(d->dev,
                                    "channel num=%d allocated!\n", chan);
                                return (NULL);
                        }
                        chan++;
                        if (chan >= max) {
                                device_printf(d->dev,
                                    "chan=%d > %d\n", chan, max);
                                return (NULL);
                        }
                }
                rpnum++;
        }

        if (*pnum != rpnum) {
                device_printf(d->dev,
                    "%s(): WARNING: pnum screwed : dirs=%s pnum=%d rpnum=%d\n",
                    __func__, dirs, *pnum, rpnum);
                return (NULL);
        }

        udc = snd_mkunit(device_get_unit(d->dev), device, chan);
        devname = dsp_unit2name(buf, sizeof(buf), udc);

        if (devname == NULL) {
                device_printf(d->dev,
                    "Failed to query device name udc=0x%08x\n", udc);
                return (NULL);
        }

        PCM_UNLOCK(d);
        ch = kmalloc(sizeof(*ch), M_DEVBUF, M_WAITOK | M_ZERO);
        ch->methods = kobj_create(cls, M_DEVBUF, M_WAITOK | M_ZERO);
        ch->unit = udc;
        ch->pid = -1;
        strlcpy(ch->comm, CHN_COMM_UNUSED, sizeof(ch->comm));
        ch->parentsnddev = d;
        ch->parentchannel = parent;
        ch->dev = d->dev;
        ch->trigger = PCMTRIG_STOP;
        ksnprintf(ch->name, sizeof(ch->name), "%s:%s:%s",
            device_get_nameunit(ch->dev), dirs, devname);

        err = chn_init(ch, devinfo, dir, direction);
        PCM_LOCK(d);
        if (err) {
                device_printf(d->dev, "chn_init(%s) failed: err = %d\n",
                    ch->name, err);
                kobj_delete(ch->methods, M_DEVBUF);
                kfree(ch, M_DEVBUF);
                return (NULL);
        }

        return (ch);
}

int
pcm_chn_destroy(struct pcm_channel *ch)
{
        struct snddev_info *d;
        int err;

        d = ch->parentsnddev;
        PCM_BUSYASSERT(d);

        err = chn_kill(ch);
        if (err) {
                device_printf(ch->dev, "chn_kill(%s) failed, err = %d\n",
                    ch->name, err);
                return (err);
        }

        kobj_delete(ch->methods, M_DEVBUF);
        kfree(ch, M_DEVBUF);

        return (0);
}

int
pcm_chn_add(struct snddev_info *d, struct pcm_channel *ch)
{
        PCM_BUSYASSERT(d);
        PCM_LOCKASSERT(d);
        KASSERT(ch != NULL && (ch->direction == PCMDIR_PLAY ||
            ch->direction == PCMDIR_REC), ("Invalid pcm channel"));

        CHN_INSERT_SORT_ASCEND(d, ch, channels.pcm);

        switch (CHN_DEV(ch)) {
        case SND_DEV_DSPHW_PLAY:
                d->playcount++;
                break;
        case SND_DEV_DSPHW_VPLAY:
                d->pvchancount++;
                break;
        case SND_DEV_DSPHW_REC:
                d->reccount++;
                break;
        case SND_DEV_DSPHW_VREC:
                d->rvchancount++;
                break;
        default:
                break;
        }

        d->devcount++;

        return (0);
}

int
pcm_chn_remove(struct snddev_info *d, struct pcm_channel *ch)
{
        struct pcm_channel *tmp;

        PCM_BUSYASSERT(d);
        PCM_LOCKASSERT(d);

        tmp = NULL;

        CHN_FOREACH(tmp, d, channels.pcm) {
                if (tmp == ch)
                        break;
        }

        if (tmp != ch)
                return (EINVAL);

        CHN_REMOVE(d, ch, channels.pcm);

        switch (CHN_DEV(ch)) {
        case SND_DEV_DSPHW_PLAY:
                d->playcount--;
                break;
        case SND_DEV_DSPHW_VPLAY:
                d->pvchancount--;
                break;
        case SND_DEV_DSPHW_REC:
                d->reccount--;
                break;
        case SND_DEV_DSPHW_VREC:
                d->rvchancount--;
                break;
        default:
                break;
        }

        d->devcount--;

        return (0);
}

int
pcm_addchan(device_t dev, int dir, kobj_class_t cls, void *devinfo)
{
        struct snddev_info *d = device_get_softc(dev);
        struct pcm_channel *ch;
        int err;

        PCM_BUSYASSERT(d);

        PCM_LOCK(d);
        ch = pcm_chn_create(d, NULL, cls, dir, -1, devinfo);
        if (!ch) {
                device_printf(d->dev, "pcm_chn_create(%s, %d, %p) failed\n",
                    cls->name, dir, devinfo);
                PCM_UNLOCK(d);
                return (ENODEV);
        }

        err = pcm_chn_add(d, ch);
        PCM_UNLOCK(d);
        if (err) {
                device_printf(d->dev, "pcm_chn_add(%s) failed, err=%d\n",
                    ch->name, err);
                pcm_chn_destroy(ch);
        }

        return (err);
}

static int
pcm_killchan(device_t dev)
{
        struct snddev_info *d = device_get_softc(dev);
        struct pcm_channel *ch;
        int error;

        PCM_BUSYASSERT(d);

        ch = CHN_FIRST(d, channels.pcm);

        PCM_LOCK(d);
        error = pcm_chn_remove(d, ch);
        PCM_UNLOCK(d);
        if (error)
                return (error);
        return (pcm_chn_destroy(ch));
}

static int
pcm_best_unit(int old)
{
        struct snddev_info *d;
        int i, best, bestprio, prio;

        best = -1;
        bestprio = -100;
        for (i = 0; pcm_devclass != NULL &&
            i < devclass_get_maxunit(pcm_devclass); i++) {
                d = devclass_get_softc(pcm_devclass, i);
                if (!PCM_REGISTERED(d))
                        continue;
                prio = 0;
                if (d->playcount == 0)
                        prio -= 10;
                if (d->reccount == 0)
                        prio -= 2;
                if (prio > bestprio || (prio == bestprio && i == old)) {
                        best = i;
                        bestprio = prio;
                }
        }
        return (best);
}

int
pcm_setstatus(device_t dev, char *str)
{
        struct snddev_info *d = device_get_softc(dev);

        PCM_BUSYASSERT(d);

        if (d->playcount == 0 || d->reccount == 0)
                d->flags |= SD_F_SIMPLEX;

        if ((d->playcount > 0 || d->reccount > 0) &&
            !(d->flags & SD_F_AUTOVCHAN)) {
                d->flags |= SD_F_AUTOVCHAN;
                vchan_initsys(dev);
        }

        pcm_setmaxautovchans(d, snd_maxautovchans);

        strlcpy(d->status, str, SND_STATUSLEN);

        PCM_LOCK(d);

        /* Last stage, enable cloning. */
        if (d->clones != NULL)
                (void)snd_clone_enable(d->clones);

        /* Done, we're ready.. */
        d->flags |= SD_F_REGISTERED;

        PCM_RELEASE(d);

        PCM_UNLOCK(d);

        if (snd_unit_auto < 0)
                snd_unit_auto = (snd_unit < 0) ? 1 : 0;
        if (snd_unit < 0 || snd_unit_auto > 1) {
                if (device_get_unit(dev) != snd_unit)
                        snd_unit = device_get_unit(dev);
        } else if (snd_unit_auto == 1) {
                snd_unit = pcm_best_unit(snd_unit);
        }

        return (0);
}

uint32_t
pcm_getflags(device_t dev)
{
        struct snddev_info *d = device_get_softc(dev);

        return d->flags;
}

void
pcm_setflags(device_t dev, uint32_t val)
{
        struct snddev_info *d = device_get_softc(dev);

        d->flags = val;
}

void *
pcm_getdevinfo(device_t dev)
{
        struct snddev_info *d = device_get_softc(dev);

        return d->devinfo;
}

unsigned int
pcm_getbuffersize(device_t dev, unsigned int minbufsz, unsigned int deflt, unsigned int maxbufsz)
{
        struct snddev_info *d = device_get_softc(dev);
        int sz, x;

        sz = 0;
        if (resource_int_value(device_get_name(dev), device_get_unit(dev), "buffersize", &sz) == 0) {
                x = sz;
                RANGE(sz, minbufsz, maxbufsz);
                if (x != sz)
                        device_printf(dev, "'buffersize=%d' hint is out of range (%d-%d), using %d\n", x, minbufsz, maxbufsz, sz);
                x = minbufsz;
                while (x < sz)
                        x <<= 1;
                if (x > sz)
                        x >>= 1;
                if (x != sz) {
                        device_printf(dev, "'buffersize=%d' hint is not a power of 2, using %d\n", sz, x);
                        sz = x;
                }
        } else {
                sz = deflt;
        }

        d->bufsz = sz;

        return sz;
}

static int
sysctl_dev_pcm_bitperfect(SYSCTL_HANDLER_ARGS)
{
        struct snddev_info *d;
        int err, val;

        d = oidp->oid_arg1;
        if (!PCM_REGISTERED(d))
                return (ENODEV);

        PCM_LOCK(d);
        PCM_WAIT(d);
        val = (d->flags & SD_F_BITPERFECT) ? 1 : 0;
        PCM_ACQUIRE(d);
        PCM_UNLOCK(d);

        err = sysctl_handle_int(oidp, &val, 0, req);

        if (err == 0 && req->newptr != NULL) {
                if (!(val == 0 || val == 1)) {
                        PCM_RELEASE_QUICK(d);
                        return (EINVAL);
                }

                PCM_LOCK(d);

                d->flags &= ~SD_F_BITPERFECT;
                d->flags |= (val != 0) ? SD_F_BITPERFECT : 0;

                PCM_RELEASE(d);
                PCM_UNLOCK(d);
        } else
                PCM_RELEASE_QUICK(d);

        return (err);
}

#ifdef SND_DEBUG
static int
sysctl_dev_pcm_clone_flags(SYSCTL_HANDLER_ARGS)
{
        struct snddev_info *d;
        uint32_t flags;
        int err;

        d = oidp->oid_arg1;
        if (!PCM_REGISTERED(d) || d->clones == NULL)
                return (ENODEV);

        PCM_ACQUIRE_QUICK(d);

        flags = snd_clone_getflags(d->clones);
        err = sysctl_handle_int(oidp, &flags, 0, req);

        if (err == 0 && req->newptr != NULL) {
                if (flags & ~SND_CLONE_MASK)
                        err = EINVAL;
                else
                        (void)snd_clone_setflags(d->clones, flags);
        }

        PCM_RELEASE_QUICK(d);

        return (err);
}

static int
sysctl_dev_pcm_clone_deadline(SYSCTL_HANDLER_ARGS)
{
        struct snddev_info *d;
        int err, deadline;

        d = oidp->oid_arg1;
        if (!PCM_REGISTERED(d) || d->clones == NULL)
                return (ENODEV);

        PCM_ACQUIRE_QUICK(d);

        deadline = snd_clone_getdeadline(d->clones);
        err = sysctl_handle_int(oidp, &deadline, 0, req);

        if (err == 0 && req->newptr != NULL) {
                if (deadline < 0)
                        err = EINVAL;
                else
                        (void)snd_clone_setdeadline(d->clones, deadline);
        }

        PCM_RELEASE_QUICK(d);

        return (err);
}

static int
sysctl_dev_pcm_clone_gc(SYSCTL_HANDLER_ARGS)
{
        struct snddev_info *d;
        int err, val;

        d = oidp->oid_arg1;
        if (!PCM_REGISTERED(d) || d->clones == NULL)
                return (ENODEV);

        val = 0;
        err = sysctl_handle_int(oidp, &val, 0, req);

        if (err == 0 && req->newptr != NULL && val != 0) {
                PCM_ACQUIRE_QUICK(d);
                val = snd_clone_gc(d->clones);
                PCM_RELEASE_QUICK(d);
                if (bootverbose != 0 || snd_verbose > 3)
                        device_printf(d->dev, "clone gc: pruned=%d\n", val);
        }

        return (err);
}

static int
sysctl_hw_snd_clone_gc(SYSCTL_HANDLER_ARGS)
{
        struct snddev_info *d;
        int i, err, val;

        val = 0;
        err = sysctl_handle_int(oidp, &val, 0, req);

        if (err == 0 && req->newptr != NULL && val != 0) {
                for (i = 0; pcm_devclass != NULL &&
                    i < devclass_get_maxunit(pcm_devclass); i++) {
                        d = devclass_get_softc(pcm_devclass, i);
                        if (!PCM_REGISTERED(d) || d->clones == NULL)
                                continue;
                        PCM_ACQUIRE_QUICK(d);
                        val = snd_clone_gc(d->clones);
                        PCM_RELEASE_QUICK(d);
                        if (bootverbose != 0 || snd_verbose > 3)
                                device_printf(d->dev, "clone gc: pruned=%d\n",
                                    val);
                }
        }

        return (err);
}
SYSCTL_PROC(_hw_snd, OID_AUTO, clone_gc, CTLTYPE_INT | CTLFLAG_RW,
    0, sizeof(int), sysctl_hw_snd_clone_gc, "I",
    "global clone garbage collector");
#endif

int
pcm_register(device_t dev, void *devinfo, int numplay, int numrec)
{
        struct snddev_info *d;
        int i;

        if (pcm_veto_load) {
                device_printf(dev, "disabled due to an error while initialising: %d\n", pcm_veto_load);

                return EINVAL;
        }

        if (device_get_unit(dev) > PCMMAXUNIT) {
                device_printf(dev, "PCMMAXUNIT reached : unit=%d > %d\n",
                    device_get_unit(dev), PCMMAXUNIT);
                device_printf(dev,
                    "Use 'hw.snd.maxunit' tunable to raise the limit.\n");
                return ENODEV;
        }

        d = device_get_softc(dev);
        d->dev = dev;
        d->lock = snd_mtxcreate(device_get_nameunit(dev), "sound cdev");
        cv_init(&d->cv, device_get_nameunit(dev));
        PCM_ACQUIRE_QUICK(d);
        dsp_cdevinfo_init(d);
#if 0
        /*
         * d->flags should be cleared by the allocator of the softc.
         * We cannot clear this field here because several devices set
         * this flag before calling pcm_register().
         */
        d->flags = 0;
#endif
        i = 0;
        if (resource_int_value(device_get_name(dev), device_get_unit(dev),
            "vpc", &i) != 0 || i != 0)
                d->flags |= SD_F_VPC;

        if (resource_int_value(device_get_name(dev), device_get_unit(dev),
            "bitperfect", &i) == 0 && i != 0)
                d->flags |= SD_F_BITPERFECT;

        d->devinfo = devinfo;
        d->devcount = 0;
        d->reccount = 0;
        d->playcount = 0;
        d->pvchancount = 0;
        d->rvchancount = 0;
        d->pvchanrate = 0;
        d->pvchanformat = 0;
        d->rvchanrate = 0;
        d->rvchanformat = 0;
        d->inprog = 0;

        /*
         * Create clone manager, disabled by default. Cloning will be
         * enabled during final stage of driver initialization through
         * pcm_setstatus().
         */
        d->clones = snd_clone_create(SND_U_MASK | SND_D_MASK, PCMMAXCLONE,
            SND_CLONE_DEADLINE_DEFAULT, SND_CLONE_WAITOK |
            SND_CLONE_GC_ENABLE | SND_CLONE_GC_UNREF |
            SND_CLONE_GC_LASTREF | SND_CLONE_GC_EXPIRED);

        CHN_INIT(d, channels.pcm);
        CHN_INIT(d, channels.pcm.busy);
        CHN_INIT(d, channels.pcm.opened);

        /* XXX This is incorrect, but lets play along for now. */
        if ((numplay == 0 || numrec == 0) && numplay != numrec)
                d->flags |= SD_F_SIMPLEX;

        sysctl_ctx_init(&d->play_sysctl_ctx);
        d->play_sysctl_tree = SYSCTL_ADD_NODE(&d->play_sysctl_ctx,
            SYSCTL_CHILDREN(device_get_sysctl_tree(dev)), OID_AUTO, "play",
            CTLFLAG_RD, 0, "playback channels node");
        sysctl_ctx_init(&d->rec_sysctl_ctx);
        d->rec_sysctl_tree = SYSCTL_ADD_NODE(&d->rec_sysctl_ctx,
            SYSCTL_CHILDREN(device_get_sysctl_tree(dev)), OID_AUTO, "rec",
            CTLFLAG_RD, 0, "record channels node");
        /* XXX: an user should be able to set this with a control tool, the
           sysadmin then needs min+max sysctls for this */
        SYSCTL_ADD_UINT(device_get_sysctl_ctx(dev),
            SYSCTL_CHILDREN(device_get_sysctl_tree(dev)),
            OID_AUTO, "buffersize", CTLFLAG_RD, &d->bufsz, 0, "allocated buffer size");
        SYSCTL_ADD_PROC(device_get_sysctl_ctx(dev),
            SYSCTL_CHILDREN(device_get_sysctl_tree(dev)), OID_AUTO,
            "bitperfect", CTLTYPE_INT | CTLFLAG_RW, d, sizeof(d),
            sysctl_dev_pcm_bitperfect, "I",
            "bit-perfect playback/recording (0=disable, 1=enable)");
#ifdef SND_DEBUG
        SYSCTL_ADD_PROC(device_get_sysctl_ctx(dev),
            SYSCTL_CHILDREN(device_get_sysctl_tree(dev)), OID_AUTO,
            "clone_flags", CTLTYPE_UINT | CTLFLAG_RW, d, sizeof(d),
            sysctl_dev_pcm_clone_flags, "IU",
            "clone flags");
        SYSCTL_ADD_PROC(device_get_sysctl_ctx(dev),
            SYSCTL_CHILDREN(device_get_sysctl_tree(dev)), OID_AUTO,
            "clone_deadline", CTLTYPE_INT | CTLFLAG_RW, d, sizeof(d),
            sysctl_dev_pcm_clone_deadline, "I",
            "clone expiration deadline (ms)");
        SYSCTL_ADD_PROC(device_get_sysctl_ctx(dev),
            SYSCTL_CHILDREN(device_get_sysctl_tree(dev)), OID_AUTO,
            "clone_gc", CTLTYPE_INT | CTLFLAG_RW, d, sizeof(d),
            sysctl_dev_pcm_clone_gc, "I",
            "clone garbage collector");
#endif

        if (numplay > 0 || numrec > 0) {
                d->flags |= SD_F_AUTOVCHAN;
                vchan_initsys(dev);
        }

        if (d->flags & SD_F_EQ)
                feeder_eq_initsys(dev);

        /* XXX use make_autoclone_dev? */
        /* XXX PCMMAXCHAN can be created for regular channels */
        d->dsp_clonedev = make_dev(&dsp_ops,
                            PCMMKMINOR(device_get_unit(dev), SND_DEV_DSP, 0),
                            UID_ROOT, GID_WHEEL, 0666, "dsp%d",
                            device_get_unit(dev));
        devfs_clone_handler_add(devtoname(d->dsp_clonedev), dsp_clone);

        sndstat_register(dev, d->status, sndstat_prepare_pcm);

        return 0;
}

int
pcm_unregister(device_t dev)
{
        struct snddev_info *d;
        struct pcm_channel *ch;
        struct thread *td;

        td = curthread;
        d = device_get_softc(dev);

        if (!PCM_ALIVE(d)) {
                device_printf(dev, "unregister: device not configured\n");
                return (0);
        }

        if (sndstat_acquire(td) != 0) {
                device_printf(dev, "unregister: sndstat busy\n");
                return (EBUSY);
        }

        PCM_LOCK(d);
        PCM_WAIT(d);

        if (d->inprog != 0) {
                device_printf(dev, "unregister: operation in progress\n");
                PCM_UNLOCK(d);
                sndstat_release(td);
                return (EBUSY);
        }

        PCM_ACQUIRE(d);
        PCM_UNLOCK(d);

        CHN_FOREACH(ch, d, channels.pcm) {
                CHN_LOCK(ch);
                if (ch->refcount > 0) {
                        device_printf(dev,
                            "unregister: channel %s busy (pid %d)\n",
                            ch->name, ch->pid);
                        CHN_UNLOCK(ch);
                        PCM_RELEASE_QUICK(d);
                        sndstat_release(td);
                        return (EBUSY);
                }
                CHN_UNLOCK(ch);
        }

        if (d->clones != NULL) {
                if (snd_clone_busy(d->clones) != 0) {
                        device_printf(dev, "unregister: clone busy\n");
                        PCM_RELEASE_QUICK(d);
                        sndstat_release(td);
                        return (EBUSY);
                } else {
                        PCM_LOCK(d);
                        (void)snd_clone_disable(d->clones);
                        PCM_UNLOCK(d);
                }
        }

        if (mixer_uninit(dev) == EBUSY) {
                device_printf(dev, "unregister: mixer busy\n");
                PCM_LOCK(d);
                if (d->clones != NULL)
                        (void)snd_clone_enable(d->clones);
                PCM_RELEASE(d);
                PCM_UNLOCK(d);
                sndstat_release(td);
                return (EBUSY);
        }

        PCM_LOCK(d);
        d->flags |= SD_F_DYING;
        d->flags &= ~SD_F_REGISTERED;
        PCM_UNLOCK(d);

        /*
         * No lock being held, so this thing can be flushed without
         * stucking into devdrn oblivion.
         */
        if (d->clones != NULL) {
                snd_clone_destroy(d->clones);
                d->clones = NULL;
        }
        devfs_clone_handler_del(devtoname(d->dsp_clonedev));
        destroy_dev(d->dsp_clonedev);

        if (d->play_sysctl_tree != NULL) {
                sysctl_ctx_free(&d->play_sysctl_ctx);
                d->play_sysctl_tree = NULL;
        }
        if (d->rec_sysctl_tree != NULL) {
                sysctl_ctx_free(&d->rec_sysctl_ctx);
                d->rec_sysctl_tree = NULL;
        }

        while (!CHN_EMPTY(d, channels.pcm))
                pcm_killchan(dev);

        dsp_cdevinfo_flush(d);

        PCM_LOCK(d);
        PCM_RELEASE(d);
        cv_destroy(&d->cv);
        PCM_UNLOCK(d);
        snd_mtxfree(d->lock);
        sndstat_unregister(dev);
        sndstat_release(td);

        if (snd_unit == device_get_unit(dev)) {
                snd_unit = pcm_best_unit(-1);
                if (snd_unit_auto == 0)
                        snd_unit_auto = 1;
        }

        return (0);
}

/************************************************************************/

/**
 * @brief       Handle OSSv4 SNDCTL_SYSINFO ioctl.
 *
 * @param si    Pointer to oss_sysinfo struct where information about the
 *              sound subsystem will be written/copied.
 *
 * This routine returns information about the sound system, such as the
 * current OSS version, number of audio, MIDI, and mixer drivers, etc.
 * Also includes a bitmask showing which of the above types of devices
 * are open (busy).
 *
 * @note
 * Calling threads must not hold any snddev_info or pcm_channel locks.
 *
 * @author      Ryan Beasley <ryanb@FreeBSD.org>
 */
void
sound_oss_sysinfo(oss_sysinfo *si)
{
        static char si_product[] = "FreeBSD native OSS ABI";
        static char si_version[] = __XSTRING(__FreeBSD_version);
        static char si_license[] = "BSD";
        static int intnbits = sizeof(int) * 8;  /* Better suited as macro?
                                                   Must pester a C guru. */

        struct snddev_info *d;
        struct pcm_channel *c;
        int i, j, ncards;
        
        ncards = 0;

        strlcpy(si->product, si_product, sizeof(si->product));
        strlcpy(si->version, si_version, sizeof(si->version));
        si->versionnum = SOUND_VERSION;
        strlcpy(si->license, si_license, sizeof(si->license));

        /*
         * Iterate over PCM devices and their channels, gathering up data
         * for the numaudios, ncards, and openedaudio fields.
         */
        si->numaudios = 0;
        bzero((void *)&si->openedaudio, sizeof(si->openedaudio));

        j = 0;

        for (i = 0; pcm_devclass != NULL &&
            i < devclass_get_maxunit(pcm_devclass); i++) {
                d = devclass_get_softc(pcm_devclass, i);
                if (!PCM_REGISTERED(d))
                        continue;

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

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

                si->numaudios += d->devcount;
                ++ncards;

                CHN_FOREACH(c, d, channels.pcm) {
                        CHN_UNLOCKASSERT(c);
                        CHN_LOCK(c);
                        if (c->flags & CHN_F_BUSY)
                                si->openedaudio[j / intnbits] |=
                                    (1 << (j % intnbits));
                        CHN_UNLOCK(c);
                        j++;
                }

                PCM_UNLOCK(d);
        }
        si->numaudioengines = si->numaudios;

        si->numsynths = 0;      /* OSSv4 docs:  this field is obsolete */
        /**
         * @todo        Collect num{midis,timers}.
         *
         * Need access to sound/midi/midi.c::midistat_lock in order
         * to safely touch midi_devices and get a head count of, well,
         * MIDI devices.  midistat_lock is a global static (i.e., local to
         * midi.c), but midi_devices is a regular global; should the mutex
         * be publicized, or is there another way to get this information?
         *
         * NB:  MIDI/sequencer stuff is currently on hold.
         */
        si->nummidis = 0;
        si->numtimers = 0;
        si->nummixers = mixer_count;
        si->numcards = ncards;
                /* OSSv4 docs:  Intended only for test apps; API doesn't
                   really have much of a concept of cards.  Shouldn't be
                   used by applications. */

        /**
         * @todo        Fill in "busy devices" fields.
         *
         *  si->openedmidi = " MIDI devices
         */
        bzero((void *)&si->openedmidi, sizeof(si->openedmidi));

        /*
         * Si->filler is a reserved array, but according to docs each
         * element should be set to -1.
         */
        for (i = 0; i < sizeof(si->filler)/sizeof(si->filler[0]); i++)
                si->filler[i] = -1;
}

int
sound_oss_card_info(oss_card_info *si)
{
        struct snddev_info *d;
        int i, ncards;
        
        ncards = 0;

        for (i = 0; pcm_devclass != NULL &&
            i < devclass_get_maxunit(pcm_devclass); i++) {
                d = devclass_get_softc(pcm_devclass, i);
                if (!PCM_REGISTERED(d))
                        continue;

                if (ncards++ != si->card)
                        continue;

                PCM_UNLOCKASSERT(d);
                PCM_LOCK(d);
                
                strlcpy(si->shortname, device_get_nameunit(d->dev),
                    sizeof(si->shortname));
                strlcpy(si->longname, device_get_desc(d->dev),
                    sizeof(si->longname));
                strlcpy(si->hw_info, d->status, sizeof(si->hw_info));
                si->intr_count = si->ack_count = 0;

                PCM_UNLOCK(d);

                return (0);
        }
        return (ENXIO);
}

/************************************************************************/

static int
sound_modevent(module_t mod, int type, void *data)
{
        int ret;

        ret = 0;

        switch(type) {
        case MOD_LOAD:
                pcmsg_unrhdr = new_unrhdr(1, INT_MAX, NULL);
                default_dsp = make_dev(&dsp_ops,
                                       PCMMKMINOR(PCMUNIT_DEFAULT,
                                                  SND_DEV_DSP, 0),
                                       UID_ROOT, GID_WHEEL, 0666, "dsp");
                if (default_dsp)
                        devfs_clone_handler_add("dsp", dsp_clone);
                default_mixer = make_dev(&mixer_ops,
                                       PCMMKMINOR(PCMUNIT_DEFAULT, 0, 0),
                                       UID_ROOT, GID_WHEEL, 0666, "mixer");
                if (default_mixer)
                        devfs_clone_handler_add("mixer", mixer_clone);
                break;
        case MOD_UNLOAD:
                ret = sndstat_acquire(curthread);
                if (ret != 0)
                        break;
                if (default_dsp) {
                        devfs_clone_handler_del("dsp");
                        destroy_dev(default_dsp);
                }
                if (default_mixer) {
                        devfs_clone_handler_del("mixer");
                        destroy_dev(default_mixer);
                }
                if (pcmsg_unrhdr != NULL) {
                        delete_unrhdr(pcmsg_unrhdr);
                        pcmsg_unrhdr = NULL;
                }
                break;
        case MOD_SHUTDOWN:
                break;
        default:
                ret = ENOTSUP;
                break;
        }
        return ret;
}

DEV_MODULE(sound, sound_modevent, NULL);
MODULE_VERSION(sound, SOUND_MODVER);