/*      $NetBSD: sequencer.c,v 1.84 2023/10/17 09:59:46 riastradh Exp $ */

/*
* Copyright (c) 1998, 2008 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Lennart Augustsson ([email protected]) and by Andrew Doran.
*
* 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
*/

/*
* Locking:
*
* o sc_lock: provides atomic access to all data structures.  Taken from
*   both process and soft interrupt context.
*
* o sc_dvlock: serializes operations on /dev/sequencer.  Taken from
*   process context.  Dropped while waiting for data in sequencerread()
*   to allow concurrent reads/writes while no data available.
*
* o sc_isopen: we allow only one concurrent open, only to prevent user
*   and/or application error.
*
* o MIDI softc locks.  These can be spinlocks and there can be many of
*   them, because we can open many MIDI devices.  We take these only in two
*   places: when enabling redirection from the MIDI device and when
*   disabling it (open/close).  midiseq_in() is called by the MIDI driver
*   with its own lock held when passing data into this module.  To avoid
*   lock order and context problems, we package the received message as a
*   sequencer_pcqitem_t and put onto a producer-consumer queue.  A soft
*   interrupt is scheduled to dequeue and decode the message later where we
*   can safely acquire the sequencer device's sc_lock.  PCQ is lockless for
*   multiple producer, single consumer settings like this one.
*/

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: sequencer.c,v 1.84 2023/10/17 09:59:46 riastradh Exp $");

#ifdef _KERNEL_OPT
#include "midi.h"
#endif

#include <sys/param.h>
#include <sys/types.h>

#include <sys/atomic.h>
#include <sys/audioio.h>
#include <sys/conf.h>
#include <sys/device.h>
#include <sys/fcntl.h>
#include <sys/intr.h>
#include <sys/ioctl.h>
#include <sys/kauth.h>
#include <sys/kernel.h>
#include <sys/kmem.h>
#include <sys/midiio.h>
#include <sys/pcq.h>
#include <sys/poll.h>
#include <sys/proc.h>
#include <sys/select.h>
#include <sys/signalvar.h>
#include <sys/syslog.h>
#include <sys/systm.h>
#include <sys/vnode.h>
#include <sys/vnode.h>

#include <dev/midi_if.h>
#include <dev/midivar.h>
#include <dev/sequencervar.h>

#include "ioconf.h"

/*
* XXX Kludge.  This module uses midi_cd, and depends on the `midi'
* module, but there's no obvious way to get midi_cd declared in
* ioconf.h without actually pulling MIDI into the module in
* sys/modules/sequencer/sequencer.ioconf.  Please fix me!
*
* XXX XXX XXX Apparently sequencer.ioconf doesn't actually make the
* sequencer cdev!  Did this ever work?
*
* XXX XXX XXX Apparently there are even some kernels that include a
* sequencer pseudo-device but exclude any midi device.  How do they
* even link??
*/
extern struct cfdriver midi_cd;
#ifdef _MODULE
extern struct cfdriver sequencer_cd;
#endif

#define ADDTIMEVAL(a, b) ( \
       (a)->tv_sec += (b)->tv_sec, \
       (a)->tv_usec += (b)->tv_usec, \
       (a)->tv_usec > 1000000 ? ((a)->tv_sec++, (a)->tv_usec -= 1000000) : 0\
       )

#define SUBTIMEVAL(a, b) ( \
       (a)->tv_sec -= (b)->tv_sec, \
       (a)->tv_usec -= (b)->tv_usec, \
       (a)->tv_usec < 0 ? ((a)->tv_sec--, (a)->tv_usec += 1000000) : 0\
       )

#ifdef AUDIO_DEBUG
#define DPRINTF(x)      do { if (sequencerdebug) printf x; } while (0)
#define DPRINTFN(n,x)   do { if (sequencerdebug >= (n)) printf x; } while (0)
int     sequencerdebug = 0;
#else
#define DPRINTF(x)      do { } while (0)
#define DPRINTFN(n,x)   do { } while (0)
#endif

#define SEQ_NOTE_MAX 128
#define SEQ_NOTE_XXX 255

#define RECALC_USPERDIV(t) \
((t)->usperdiv = 60*1000000L/((t)->tempo_beatpermin*(t)->timebase_divperbeat))

typedef union sequencer_pcqitem {
       void    *qi_ptr;
       char    qi_msg[4];
} sequencer_pcqitem_t;

static void seq_reset(struct sequencer_softc *);
static int seq_do_command(struct sequencer_softc *, seq_event_t *);
static int seq_do_chnvoice(struct sequencer_softc *, seq_event_t *);
static int seq_do_chncommon(struct sequencer_softc *, seq_event_t *);
static void seq_timer_waitabs(struct sequencer_softc *, uint32_t);
static int seq_do_timing(struct sequencer_softc *, seq_event_t *);
static int seq_do_local(struct sequencer_softc *, seq_event_t *);
static int seq_do_sysex(struct sequencer_softc *, seq_event_t *);
static int seq_do_fullsize(struct sequencer_softc *, seq_event_t *,
   struct uio *);
static int seq_input_event(struct sequencer_softc *, seq_event_t *);
static int seq_drain(struct sequencer_softc *);
static void seq_startoutput(struct sequencer_softc *);
static void seq_timeout(void *);
static int seq_to_new(seq_event_t *, struct uio *);
static void seq_softintr(void *);

static int midiseq_out(struct midi_dev *, u_char *, u_int, int);
static struct midi_dev *midiseq_open(int, int);
static void midiseq_close(struct midi_dev *);
static void midiseq_reset(struct midi_dev *);
static int midiseq_noteon(struct midi_dev *, int, int, seq_event_t *);
static int midiseq_noteoff(struct midi_dev *, int, int, seq_event_t *);
static int midiseq_keypressure(struct midi_dev *, int, int, seq_event_t *);
static int midiseq_pgmchange(struct midi_dev *, int, seq_event_t *);
static int midiseq_chnpressure(struct midi_dev *, int, seq_event_t *);
static int midiseq_ctlchange(struct midi_dev *, int, seq_event_t *);
static int midiseq_pitchbend(struct midi_dev *, int, seq_event_t *);
static int midiseq_loadpatch(struct midi_dev *, struct sysex_info *,
   struct uio *);
void midiseq_in(struct midi_dev *, u_char *, int);

static dev_type_open(sequenceropen);
static dev_type_close(sequencerclose);
static dev_type_read(sequencerread);
static dev_type_write(sequencerwrite);
static dev_type_ioctl(sequencerioctl);
static dev_type_poll(sequencerpoll);
static dev_type_kqfilter(sequencerkqfilter);

const struct cdevsw sequencer_cdevsw = {
       .d_open = sequenceropen,
       .d_close = sequencerclose,
       .d_read = sequencerread,
       .d_write = sequencerwrite,
       .d_ioctl = sequencerioctl,
       .d_stop = nostop,
       .d_tty = notty,
       .d_poll = sequencerpoll,
       .d_mmap = nommap,
       .d_kqfilter = sequencerkqfilter,
       .d_discard = nodiscard,
       .d_flag = D_OTHER | D_MPSAFE
};
static LIST_HEAD(, sequencer_softc) sequencers =
   LIST_HEAD_INITIALIZER(sequencers);
static kmutex_t sequencer_lock;

static void
sequencerdestroy(struct sequencer_softc *sc)
{

       callout_halt(&sc->sc_callout, &sc->lock);
       callout_destroy(&sc->sc_callout);
       softint_disestablish(sc->sih);
       cv_destroy(&sc->rchan);
       cv_destroy(&sc->wchan);
       cv_destroy(&sc->lchan);
       if (sc->pcq)
               pcq_destroy(sc->pcq);
       kmem_free(sc, sizeof(*sc));
}

static struct sequencer_softc *
sequencercreate(int unit)
{
       struct sequencer_softc *sc = kmem_zalloc(sizeof(*sc), KM_SLEEP);

       sc->sc_unit = unit;
       callout_init(&sc->sc_callout, CALLOUT_MPSAFE);
       sc->sih = softint_establish(SOFTINT_NET | SOFTINT_MPSAFE,
           seq_softintr, sc);
       mutex_init(&sc->lock, MUTEX_DEFAULT, IPL_NONE);
       cv_init(&sc->rchan, "midiseqr");
       cv_init(&sc->wchan, "midiseqw");
       cv_init(&sc->lchan, "midiseql");
       sc->pcq = pcq_create(SEQ_MAXQ, KM_SLEEP);
       if (sc->pcq == NULL) {
               sequencerdestroy(sc);
               return NULL;
       }
       return sc;
}


static struct sequencer_softc *
sequencerget(int unit)
{
       struct sequencer_softc *sc;

       KASSERTMSG(unit >= 0, "unit=%d", unit);

       if (unit < 0)
               return NULL;

       mutex_enter(&sequencer_lock);
       LIST_FOREACH(sc, &sequencers, sc_link) {
               if (sc->sc_unit == unit) {
                       mutex_exit(&sequencer_lock);
                       return sc;
               }
       }
       mutex_exit(&sequencer_lock);

       /*
        * XXXSMP -- nothing excludes another thread from creating the
        * same unit here
        */
       if ((sc = sequencercreate(unit)) == NULL)
               return NULL;

       mutex_enter(&sequencer_lock);
       LIST_INSERT_HEAD(&sequencers, sc, sc_link);
       mutex_exit(&sequencer_lock);

       return sc;
}

#ifdef notyet
static void
sequencerput(struct sequencer_softc *sc)
{

       mutex_enter(&sequencer_lock);
       LIST_REMOVE(sc, sc_link);
       mutex_exit(&sequencer_lock);
       sequencerdestroy(sc);
}
#endif

void
sequencerattach(int n)
{

       mutex_init(&sequencer_lock, MUTEX_DEFAULT, IPL_NONE);
}

/*
* Release reference to device acquired with sequencer_enter().
*/
static void
sequencer_exit(struct sequencer_softc *sc)
{

       sc->dvlock--;
       cv_broadcast(&sc->lchan);
       mutex_exit(&sc->lock);
}

/*
* Look up sequencer device and acquire locks for device access.
*/
static int
sequencer_enter(dev_t dev, struct sequencer_softc **scp)
{
       struct sequencer_softc *sc;

       /* First, find the device and take sc_lock. */
       if ((sc = sequencerget(SEQUENCERUNIT(dev))) == NULL)
               return ENXIO;

       mutex_enter(&sc->lock);
       while (sc->dvlock) {
               cv_wait(&sc->lchan, &sc->lock);
       }
       sc->dvlock++;
       if (sc->dying) {
               sequencer_exit(sc);
               return EIO;
       }
       *scp = sc;
       return 0;
}

static int
sequenceropen(dev_t dev, int flags, int ifmt, struct lwp *l)
{
       struct sequencer_softc *sc;
       struct midi_dev *md;
       struct midi_softc *msc;
       int error, unit, mdno;

       DPRINTF(("sequenceropen\n"));

       if ((error = sequencer_enter(dev, &sc)) != 0)
               return error;
       if (sc->isopen != 0) {
               sequencer_exit(sc);
               return EBUSY;
       }

       if (SEQ_IS_OLD(SEQUENCERUNIT(dev)))
               sc->mode = SEQ_OLD;
       else
               sc->mode = SEQ_NEW;
       sc->isopen++;
       sc->flags = flags & (FREAD|FWRITE);
       sc->pbus = 0;
       sc->async = 0;
       sc->input_stamp = ~0;

       sc->nmidi = 0;
       sc->ndevs = midi_unit_count();
       sc->timer.timebase_divperbeat = 100;
       sc->timer.tempo_beatpermin = 60;
       RECALC_USPERDIV(&sc->timer);
       sc->timer.divs_lastevent = sc->timer.divs_lastchange = 0;
       microtime(&sc->timer.reftime);

       SEQ_QINIT(&sc->inq);
       SEQ_QINIT(&sc->outq);
       sc->lowat = SEQ_MAXQ / 2;

       if (sc->ndevs > 0) {
               mutex_exit(&sc->lock);
               sc->devs = kmem_alloc(sc->ndevs * sizeof(struct midi_dev *),
                   KM_SLEEP);
               for (unit = 0; unit < sc->ndevs; unit++) {
                       md = midiseq_open(unit, flags);
                       if (md) {
                               sc->devs[sc->nmidi++] = md;
                               md->seq = sc;
                               md->doingsysex = 0;
                               DPRINTF(("%s: midi unit %d opened as seq %p\n",
                                   __func__, unit, md));
                       } else {
                               DPRINTF(("%s: midi unit %d not opened as seq\n",
                                   __func__, unit));
                       }
               }
               mutex_enter(&sc->lock);
       } else {
               sc->devs = NULL;
       }

       /* Only now redirect input from MIDI devices. */
       for (mdno = 0; mdno < sc->nmidi; mdno++) {
               msc = device_lookup_private(&midi_cd, sc->devs[mdno]->unit);
               if (msc) {
                       mutex_enter(msc->lock);
                       msc->seqopen = 1;
                       mutex_exit(msc->lock);
               }
       }

       seq_reset(sc);
       sequencer_exit(sc);

       DPRINTF(("%s: mode=%d, nmidi=%d\n", __func__, sc->mode, sc->nmidi));
       return 0;
}

static int
seq_drain(struct sequencer_softc *sc)
{
       int error;

       KASSERT(mutex_owned(&sc->lock));

       DPRINTFN(3, ("seq_drain: %p, len=%d\n", sc, SEQ_QLEN(&sc->outq)));
       seq_startoutput(sc);
       error = 0;
       while (!SEQ_QEMPTY(&sc->outq) && !error)
               error = cv_timedwait_sig(&sc->wchan, &sc->lock, 60*hz);
       return error;
}

static void
seq_timeout(void *addr)
{
       struct sequencer_softc *sc = addr;
       proc_t *p;
       pid_t pid;

       DPRINTFN(4, ("seq_timeout: %p\n", sc));

       mutex_enter(&sc->lock);
       if (sc->timeout == 0) {
               mutex_exit(&sc->lock);
               return;
       }
       sc->timeout = 0;
       seq_startoutput(sc);
       if (SEQ_QLEN(&sc->outq) >= sc->lowat) {
               mutex_exit(&sc->lock);
               return;
       }
       cv_broadcast(&sc->wchan);
       selnotify(&sc->wsel, 0, NOTE_SUBMIT);
       if ((pid = sc->async) != 0) {
               mutex_enter(&proc_lock);
               if ((p = proc_find(pid)) != NULL)
                       psignal(p, SIGIO);
               mutex_exit(&proc_lock);
       }
       mutex_exit(&sc->lock);
}

static void
seq_startoutput(struct sequencer_softc *sc)
{
       struct sequencer_queue *q = &sc->outq;
       seq_event_t cmd;

       KASSERT(mutex_owned(&sc->lock));

       if (sc->timeout)
               return;
       DPRINTFN(4, ("seq_startoutput: %p, len=%d\n", sc, SEQ_QLEN(q)));
       while (!SEQ_QEMPTY(q) && !sc->timeout) {
               SEQ_QGET(q, cmd);
               seq_do_command(sc, &cmd);
       }
}

static int
sequencerclose(dev_t dev, int flags, int ifmt, struct lwp *l)
{
       struct sequencer_softc *sc;
       struct midi_softc *msc;
       int unit, error;

       DPRINTF(("%s: %"PRIx64"\n", __func__, dev));

       if ((error = sequencer_enter(dev, &sc)) != 0)
               return error;
       seq_drain(sc);
       if (sc->timeout) {
               callout_halt(&sc->sc_callout, &sc->lock);
               sc->timeout = 0;
       }
       /* Bin input from MIDI devices. */
       for (unit = 0; unit < sc->nmidi; unit++) {
               msc = device_lookup_private(&midi_cd, unit);
               if (msc) {
                       mutex_enter(msc->lock);
                       msc->seqopen = 0;
                       mutex_exit(msc->lock);
               }
       }
       mutex_exit(&sc->lock);

       for (unit = 0; unit < sc->nmidi; unit++)
               if (sc->devs[unit] != NULL)
                       midiseq_close(sc->devs[unit]);
       if (sc->devs != NULL) {
               KASSERT(sc->ndevs > 0);
               kmem_free(sc->devs, sc->ndevs * sizeof(struct midi_dev *));
               sc->devs = NULL;
       }

       mutex_enter(&sc->lock);
       sc->isopen = 0;
       sequencer_exit(sc);

       DPRINTF(("%s: %"PRIx64" done\n", __func__, dev));

       return 0;
}

static int
seq_input_event(struct sequencer_softc *sc, seq_event_t *cmd)
{
       struct sequencer_queue *q;

       KASSERT(mutex_owned(&sc->lock));

       DPRINTFN(2, ("seq_input_event: %02x %02x %02x %02x %02x "
           "%02x %02x %02x\n", cmd->tag,
           cmd->unknown.byte[0], cmd->unknown.byte[1],
           cmd->unknown.byte[2], cmd->unknown.byte[3],
           cmd->unknown.byte[4], cmd->unknown.byte[5],
           cmd->unknown.byte[6]));
       q = &sc->inq;
       if (SEQ_QFULL(q))
               return ENOMEM;
       SEQ_QPUT(q, *cmd);
       cv_broadcast(&sc->rchan);
       selnotify(&sc->rsel, 0, NOTE_SUBMIT);
       if (sc->async != 0) {
               proc_t *p;

               mutex_enter(&proc_lock);
               if ((p = proc_find(sc->async)) != NULL)
                       psignal(p, SIGIO);
               mutex_exit(&proc_lock);
       }
       return 0;
}

static void
seq_softintr(void *addr)
{
       struct sequencer_softc *sc;
       struct timeval now;
       seq_event_t ev;
       int status, chan, unit;
       sequencer_pcqitem_t qi;
       u_long t;

       sc = addr;

       mutex_enter(&sc->lock);

       qi.qi_ptr = pcq_get(sc->pcq);
       if (qi.qi_ptr == NULL) {
               mutex_exit(&sc->lock);
               return;
       }
       KASSERT((qi.qi_msg[3] & 0x80) != 0);
       unit = qi.qi_msg[3] & ~0x80;
       status = MIDI_GET_STATUS(qi.qi_msg[0]);
       chan = MIDI_GET_CHAN(qi.qi_msg[0]);
       switch (status) {
       case MIDI_NOTEON: /* midi(4) always canonicalizes hidden note-off */
               ev = SEQ_MK_CHN(NOTEON, .device=unit, .channel=chan,
                   .key=qi.qi_msg[1], .velocity=qi.qi_msg[2]);
               break;
       case MIDI_NOTEOFF:
               ev = SEQ_MK_CHN(NOTEOFF, .device=unit, .channel=chan,
                   .key=qi.qi_msg[1], .velocity=qi.qi_msg[2]);
               break;
       case MIDI_KEY_PRESSURE:
               ev = SEQ_MK_CHN(KEY_PRESSURE, .device=unit, .channel=chan,
                   .key=qi.qi_msg[1], .pressure=qi.qi_msg[2]);
               break;
       case MIDI_CTL_CHANGE: /* XXX not correct for MSB */
               ev = SEQ_MK_CHN(CTL_CHANGE, .device=unit, .channel=chan,
                   .controller=qi.qi_msg[1], .value=qi.qi_msg[2]);
               break;
       case MIDI_PGM_CHANGE:
               ev = SEQ_MK_CHN(PGM_CHANGE, .device=unit, .channel=chan,
                   .program=qi.qi_msg[1]);
               break;
       case MIDI_CHN_PRESSURE:
               ev = SEQ_MK_CHN(CHN_PRESSURE, .device=unit, .channel=chan,
                   .pressure=qi.qi_msg[1]);
               break;
       case MIDI_PITCH_BEND:
               ev = SEQ_MK_CHN(PITCH_BEND, .device=unit, .channel=chan,
                   .value=(qi.qi_msg[1] & 0x7f) | ((qi.qi_msg[2] & 0x7f) << 7));
               break;
       default: /* this is now the point where MIDI_ACKs disappear */
               mutex_exit(&sc->lock);
               return;
       }
       microtime(&now);
       if (!sc->timer.running)
               now = sc->timer.stoptime;
       SUBTIMEVAL(&now, &sc->timer.reftime);
       t = now.tv_sec * 1000000 + now.tv_usec;
       t /= sc->timer.usperdiv;
       t += sc->timer.divs_lastchange;
       if (t != sc->input_stamp) {
               seq_input_event(sc, &SEQ_MK_TIMING(WAIT_ABS, .divisions=t));
               sc->input_stamp = t; /* XXX what happens if timer is reset? */
       }
       seq_input_event(sc, &ev);
       mutex_exit(&sc->lock);
}

static int
sequencerread(dev_t dev, struct uio *uio, int ioflag)
{
       struct sequencer_softc *sc;
       struct sequencer_queue *q;
       seq_event_t ev;
       int error;

       DPRINTFN(2, ("sequencerread: %"PRIx64", count=%d, ioflag=%x\n",
          dev, (int)uio->uio_resid, ioflag));

       if ((error = sequencer_enter(dev, &sc)) != 0)
               return error;
       q = &sc->inq;

       if (sc->mode == SEQ_OLD) {
               sequencer_exit(sc);
               DPRINTFN(-1,("sequencerread: old read\n"));
               return EINVAL; /* XXX unimplemented */
       }
       while (SEQ_QEMPTY(q)) {
               if (ioflag & IO_NDELAY) {
                       error = EWOULDBLOCK;
                       break;
               }
               /* Drop lock to allow concurrent read/write. */
               KASSERT(sc->dvlock != 0);
               sc->dvlock--;
               error = cv_wait_sig(&sc->rchan, &sc->lock);
               while (sc->dvlock != 0) {
                       cv_wait(&sc->lchan, &sc->lock);
               }
               sc->dvlock++;
               if (error) {
                       break;
               }
       }
       while (uio->uio_resid >= sizeof(ev) && !error && !SEQ_QEMPTY(q)) {
               SEQ_QGET(q, ev);
               mutex_exit(&sc->lock);
               error = uiomove(&ev, sizeof(ev), uio);
               mutex_enter(&sc->lock);
       }
       sequencer_exit(sc);
       return error;
}

static int
sequencerwrite(dev_t dev, struct uio *uio, int ioflag)
{
       struct sequencer_softc *sc;
       struct sequencer_queue *q;
       int error;
       seq_event_t cmdbuf;
       int size;

       DPRINTFN(2, ("sequencerwrite: %"PRIx64", count=%d\n", dev,
           (int)uio->uio_resid));

       if ((error = sequencer_enter(dev, &sc)) != 0)
               return error;
       q = &sc->outq;

       size = sc->mode == SEQ_NEW ? sizeof cmdbuf : SEQOLD_CMDSIZE;
       while (uio->uio_resid >= size && error == 0) {
               mutex_exit(&sc->lock);
               error = uiomove(&cmdbuf, size, uio);
               if (error == 0) {
                       if (sc->mode == SEQ_OLD && seq_to_new(&cmdbuf, uio)) {
                               mutex_enter(&sc->lock);
                               continue;
                       }
                       if (cmdbuf.tag == SEQ_FULLSIZE) {
                               /* We do it like OSS does, asynchronously */
                               error = seq_do_fullsize(sc, &cmdbuf, uio);
                               if (error == 0) {
                                       mutex_enter(&sc->lock);
                                       continue;
                               }
                       }
               }
               mutex_enter(&sc->lock);
               if (error != 0) {
                       break;
               }
               while (SEQ_QFULL(q)) {
                       seq_startoutput(sc);
                       if (SEQ_QFULL(q)) {
                               if (ioflag & IO_NDELAY) {
                                       error = EWOULDBLOCK;
                                       break;
                               }
                               error = cv_wait_sig(&sc->wchan, &sc->lock);
                               if (error) {
                                        break;
                               }
                       }
               }
               if (error == 0) {
                       SEQ_QPUT(q, cmdbuf);
               }
       }
       if (error == 0) {
               seq_startoutput(sc);
       } else {
               DPRINTFN(2, ("sequencerwrite: error=%d\n", error));
       }
       sequencer_exit(sc);
       return error;
}

static int
sequencerioctl(dev_t dev, u_long cmd, void *addr, int flag, struct lwp *l)
{
       struct sequencer_softc *sc;
       struct synth_info *si;
       struct midi_dev *md;
       int devno, error, t;
       struct timeval now;
       u_long tx;

       DPRINTFN(2, ("sequencerioctl: %"PRIx64" cmd=0x%08lx\n", dev, cmd));

       if ((error = sequencer_enter(dev, &sc)) != 0)
               return error;
       switch (cmd) {
       case FIONBIO:
               /* All handled in the upper FS layer. */
               break;

       case FIOASYNC:
               if (*(int *)addr) {
                       if (sc->async != 0) {
                               error = EBUSY;
                               break;
                       }
                       sc->async = curproc->p_pid;
                       DPRINTF(("%s: FIOASYNC %d\n", __func__,
                           sc->async));
               } else {
                       sc->async = 0;
               }
               break;

       case SEQUENCER_RESET:
               seq_reset(sc);
               break;

       case SEQUENCER_PANIC:
               seq_reset(sc);
               /* Do more?  OSS doesn't */
               break;

       case SEQUENCER_SYNC:
               if (sc->flags != FREAD)
                       seq_drain(sc);
               break;

       case SEQUENCER_INFO:
               si = (struct synth_info*)addr;
               devno = si->device;
               if (devno < 0 || devno >= sc->nmidi) {
                       error = EINVAL;
                       break;
               }
               md = sc->devs[devno];
               strncpy(si->name, md->name, sizeof si->name);
               si->synth_type = SYNTH_TYPE_MIDI;
               si->synth_subtype = md->subtype;
               si->nr_voices = md->nr_voices;
               si->instr_bank_size = md->instr_bank_size;
               si->capabilities = md->capabilities;
               break;

       case SEQUENCER_NRSYNTHS:
               *(int *)addr = sc->nmidi;
               break;

       case SEQUENCER_NRMIDIS:
               *(int *)addr = sc->nmidi;
               break;

       case SEQUENCER_OUTOFBAND:
               DPRINTFN(3, ("sequencer_ioctl: OOB=%02x %02x %02x %02x %02x %02x %02x %02x\n",
                   *(u_char *)addr, *((u_char *)addr+1),
                   *((u_char *)addr+2), *((u_char *)addr+3),
                   *((u_char *)addr+4), *((u_char *)addr+5),
                   *((u_char *)addr+6), *((u_char *)addr+7)));
               if ((sc->flags & FWRITE) == 0) {
                       error = EBADF;
               } else {
                       error = seq_do_command(sc, (seq_event_t *)addr);
               }
               break;

       case SEQUENCER_TMR_TIMEBASE:
               t = *(int *)addr;
               if (t < 1)
                       t = 1;
               if (t > 10000)
                       t = 10000;
               *(int *)addr = t;
               sc->timer.timebase_divperbeat = t;
               sc->timer.divs_lastchange = sc->timer.divs_lastevent;
               microtime(&sc->timer.reftime);
               RECALC_USPERDIV(&sc->timer);
               break;

       case SEQUENCER_TMR_START:
               error = seq_do_timing(sc, &SEQ_MK_TIMING(START));
               break;

       case SEQUENCER_TMR_STOP:
               error = seq_do_timing(sc, &SEQ_MK_TIMING(STOP));
               break;

       case SEQUENCER_TMR_CONTINUE:
               error = seq_do_timing(sc, &SEQ_MK_TIMING(CONTINUE));
               break;

       case SEQUENCER_TMR_TEMPO:
               error = seq_do_timing(sc,
                   &SEQ_MK_TIMING(TEMPO, .bpm=*(int *)addr));
               RECALC_USPERDIV(&sc->timer);
               if (error == 0)
                       *(int *)addr = sc->timer.tempo_beatpermin;
               break;

       case SEQUENCER_TMR_SOURCE:
               *(int *)addr = SEQUENCER_TMR_INTERNAL;
               break;

       case SEQUENCER_TMR_METRONOME:
               /* noop */
               break;

       case SEQUENCER_THRESHOLD:
               t = SEQ_MAXQ - *(int *)addr / sizeof (seq_event_rec);
               if (t < 1)
                       t = 1;
               if (t > SEQ_MAXQ)
                       t = SEQ_MAXQ;
               sc->lowat = t;
               break;

       case SEQUENCER_CTRLRATE:
               *(int *)addr = (sc->timer.tempo_beatpermin
                   *sc->timer.timebase_divperbeat + 30) / 60;
               break;

       case SEQUENCER_GETTIME:
               microtime(&now);
               SUBTIMEVAL(&now, &sc->timer.reftime);
               tx = now.tv_sec * 1000000 + now.tv_usec;
               tx /= sc->timer.usperdiv;
               tx += sc->timer.divs_lastchange;
               *(int *)addr = tx;
               break;

       default:
               DPRINTFN(-1,("sequencer_ioctl: unimpl %08lx\n", cmd));
               error = EINVAL;
               break;
       }
       sequencer_exit(sc);

       return error;
}

static int
sequencerpoll(dev_t dev, int events, struct lwp *l)
{
       struct sequencer_softc *sc;
       int revents = 0;

       if ((sc = sequencerget(SEQUENCERUNIT(dev))) == NULL)
               return ENXIO;

       DPRINTF(("%s: %p events=0x%x\n", __func__, sc, events));

       mutex_enter(&sc->lock);
       if (events & (POLLIN | POLLRDNORM))
               if ((sc->flags&FREAD) && !SEQ_QEMPTY(&sc->inq))
                       revents |= events & (POLLIN | POLLRDNORM);

       if (events & (POLLOUT | POLLWRNORM))
               if ((sc->flags&FWRITE) && SEQ_QLEN(&sc->outq) < sc->lowat)
                       revents |= events & (POLLOUT | POLLWRNORM);

       if (revents == 0) {
               if ((sc->flags&FREAD) && (events & (POLLIN | POLLRDNORM)))
                       selrecord(l, &sc->rsel);

               if ((sc->flags&FWRITE) && (events & (POLLOUT | POLLWRNORM)))
                       selrecord(l, &sc->wsel);
       }
       mutex_exit(&sc->lock);

       return revents;
}

static void
filt_sequencerrdetach(struct knote *kn)
{
       struct sequencer_softc *sc = kn->kn_hook;

       mutex_enter(&sc->lock);
       selremove_knote(&sc->rsel, kn);
       mutex_exit(&sc->lock);
}

static int
filt_sequencerread(struct knote *kn, long hint)
{
       struct sequencer_softc *sc = kn->kn_hook;
       int rv;

       if (hint != NOTE_SUBMIT) {
               mutex_enter(&sc->lock);
       }
       if (SEQ_QEMPTY(&sc->inq)) {
               rv = 0;
       } else {
               kn->kn_data = sizeof(seq_event_rec);
               rv = 1;
       }
       if (hint != NOTE_SUBMIT) {
               mutex_exit(&sc->lock);
       }
       return rv;
}

static const struct filterops sequencerread_filtops = {
       .f_flags = FILTEROP_ISFD,
       .f_attach = NULL,
       .f_detach = filt_sequencerrdetach,
       .f_event = filt_sequencerread,
};

static void
filt_sequencerwdetach(struct knote *kn)
{
       struct sequencer_softc *sc = kn->kn_hook;

       mutex_enter(&sc->lock);
       selremove_knote(&sc->wsel, kn);
       mutex_exit(&sc->lock);
}

static int
filt_sequencerwrite(struct knote *kn, long hint)
{
       struct sequencer_softc *sc = kn->kn_hook;
       int rv;

       if (hint != NOTE_SUBMIT) {
               mutex_enter(&sc->lock);
       }
       if (SEQ_QLEN(&sc->outq) >= sc->lowat) {
               rv = 0;
       } else {
               kn->kn_data = sizeof(seq_event_rec);
               rv = 1;
       }
       if (hint != NOTE_SUBMIT) {
               mutex_exit(&sc->lock);
       }
       return rv;
}

static const struct filterops sequencerwrite_filtops = {
       .f_flags = FILTEROP_ISFD,
       .f_attach = NULL,
       .f_detach = filt_sequencerwdetach,
       .f_event = filt_sequencerwrite,
};

static int
sequencerkqfilter(dev_t dev, struct knote *kn)
{
       struct sequencer_softc *sc;
       struct selinfo *sip;

       if ((sc = sequencerget(SEQUENCERUNIT(dev))) == NULL)
               return ENXIO;

       switch (kn->kn_filter) {
       case EVFILT_READ:
               sip = &sc->rsel;
               kn->kn_fop = &sequencerread_filtops;
               break;

       case EVFILT_WRITE:
               sip = &sc->wsel;
               kn->kn_fop = &sequencerwrite_filtops;
               break;

       default:
               return EINVAL;
       }

       kn->kn_hook = sc;

       mutex_enter(&sc->lock);
       selrecord_knote(sip, kn);
       mutex_exit(&sc->lock);

       return 0;
}

static void
seq_reset(struct sequencer_softc *sc)
{
       int i, chn;
       struct midi_dev *md;

       KASSERT(mutex_owned(&sc->lock));

       if (!(sc->flags & FWRITE))
               return;
       for (i = 0; i < sc->nmidi; i++) {
               md = sc->devs[i];
               midiseq_reset(md);
               for (chn = 0; chn < MAXCHAN; chn++) {
                       midiseq_ctlchange(md, chn, &SEQ_MK_CHN(CTL_CHANGE,
                           .controller=MIDI_CTRL_NOTES_OFF));
                       midiseq_ctlchange(md, chn, &SEQ_MK_CHN(CTL_CHANGE,
                           .controller=MIDI_CTRL_RESET));
                       midiseq_pitchbend(md, chn, &SEQ_MK_CHN(PITCH_BEND,
                           .value=MIDI_BEND_NEUTRAL));
               }
       }
}

static int
seq_do_command(struct sequencer_softc *sc, seq_event_t *b)
{
       int dev;

       KASSERT(mutex_owned(&sc->lock));

       DPRINTFN(4, ("seq_do_command: %p cmd=0x%02x\n", sc, b->timing.op));

       switch(b->tag) {
       case SEQ_LOCAL:
               return seq_do_local(sc, b);
       case SEQ_TIMING:
               return seq_do_timing(sc, b);
       case SEQ_CHN_VOICE:
               return seq_do_chnvoice(sc, b);
       case SEQ_CHN_COMMON:
               return seq_do_chncommon(sc, b);
       case SEQ_SYSEX:
               return seq_do_sysex(sc, b);
       /* COMPAT */
       case SEQOLD_MIDIPUTC:
               dev = b->putc.device;
               if (dev < 0 || dev >= sc->nmidi)
                       return ENXIO;
               return midiseq_out(sc->devs[dev], &b->putc.byte, 1, 0);
       default:
               DPRINTFN(-1,("seq_do_command: unimpl command %02x\n", b->tag));
               return EINVAL;
       }
}

static int
seq_do_chnvoice(struct sequencer_softc *sc, seq_event_t *b)
{
       int dev;
       int error;
       struct midi_dev *md;

       KASSERT(mutex_owned(&sc->lock));

       dev = b->voice.device;
       if (dev < 0 || dev >= sc->nmidi ||
           b->voice.channel > 15 ||
           b->voice.key >= SEQ_NOTE_MAX)
               return ENXIO;
       md = sc->devs[dev];
       switch(b->voice.op) {
       case MIDI_NOTEON: /* no need to special-case hidden noteoff here */
               error = midiseq_noteon(md, b->voice.channel, b->voice.key, b);
               break;
       case MIDI_NOTEOFF:
               error = midiseq_noteoff(md, b->voice.channel, b->voice.key, b);
               break;
       case MIDI_KEY_PRESSURE:
               error = midiseq_keypressure(md,
                   b->voice.channel, b->voice.key, b);
               break;
       default:
               DPRINTFN(-1,("seq_do_chnvoice: unimpl command %02x\n",
                       b->voice.op));
               error = EINVAL;
               break;
       }
       return error;
}

static int
seq_do_chncommon(struct sequencer_softc *sc, seq_event_t *b)
{
       int dev;
       int error;
       struct midi_dev *md;

       KASSERT(mutex_owned(&sc->lock));

       dev = b->common.device;
       if (dev < 0 || dev >= sc->nmidi ||
           b->common.channel > 15)
               return ENXIO;
       md = sc->devs[dev];
       DPRINTFN(2,("seq_do_chncommon: %02x\n", b->common.op));

       error = 0;
       switch(b->common.op) {
       case MIDI_PGM_CHANGE:
               error = midiseq_pgmchange(md, b->common.channel, b);
               break;
       case MIDI_CTL_CHANGE:
               error = midiseq_ctlchange(md, b->common.channel, b);
               break;
       case MIDI_PITCH_BEND:
               error = midiseq_pitchbend(md, b->common.channel, b);
               break;
       case MIDI_CHN_PRESSURE:
               error = midiseq_chnpressure(md, b->common.channel, b);
               break;
       default:
               DPRINTFN(-1,("seq_do_chncommon: unimpl command %02x\n",
                       b->common.op));
               error = EINVAL;
               break;
       }
       return error;
}

static int
seq_do_local(struct sequencer_softc *sc, seq_event_t *b)
{

       KASSERT(mutex_owned(&sc->lock));

       return EINVAL;
}

static int
seq_do_sysex(struct sequencer_softc *sc, seq_event_t *b)
{
       int dev, i;
       struct midi_dev *md;
       uint8_t *bf = b->sysex.buffer;

       KASSERT(mutex_owned(&sc->lock));

       dev = b->sysex.device;
       if (dev < 0 || dev >= sc->nmidi)
               return ENXIO;
       DPRINTF(("%s: dev=%d\n", __func__, dev));
       md = sc->devs[dev];

       if (!md->doingsysex) {
               midiseq_out(md, (uint8_t[]){MIDI_SYSEX_START}, 1, 0);
               md->doingsysex = 1;
       }

       for (i = 0; i < 6 && bf[i] != 0xff; i++)
               ;
       midiseq_out(md, bf, i, 0);
       if (i < 6 || (i > 0 && bf[i-1] == MIDI_SYSEX_END))
               md->doingsysex = 0;
       return 0;
}

static void
seq_timer_waitabs(struct sequencer_softc *sc, uint32_t divs)
{
       struct timeval when;
       long long usec;
       struct syn_timer *t;
       int ticks;

       KASSERT(mutex_owned(&sc->lock));

       t = &sc->timer;
       t->divs_lastevent = divs;
       divs -= t->divs_lastchange;
       usec = (long long)divs * (long long)t->usperdiv; /* convert to usec */
       when.tv_sec = usec / 1000000;
       when.tv_usec = usec % 1000000;
       DPRINTFN(4, ("seq_timer_waitabs: adjdivs=%d, sleep when=%"PRId64".%06"PRId64,
                    divs, when.tv_sec, (uint64_t)when.tv_usec));
       ADDTIMEVAL(&when, &t->reftime); /* abstime for end */
       ticks = tvhzto(&when);
       DPRINTFN(4, (" when+start=%"PRId64".%06"PRId64", tick=%d\n",
                    when.tv_sec, (uint64_t)when.tv_usec, ticks));
       if (ticks > 0) {
#ifdef DIAGNOSTIC
               if (ticks > 20 * hz) {
                       /* Waiting more than 20s */
                       printf("seq_timer_waitabs: funny ticks=%d, "
                              "usec=%lld\n", ticks, usec);
               }
#endif
               sc->timeout = 1;
               callout_reset(&sc->sc_callout, ticks,
                   seq_timeout, sc);
       }
#ifdef SEQUENCER_DEBUG
       else if (tick < 0)
               DPRINTF(("%s: ticks = %d\n", __func__, ticks));
#endif
}

static int
seq_do_timing(struct sequencer_softc *sc, seq_event_t *b)
{
       struct syn_timer *t = &sc->timer;
       struct timeval when;
       int error;

       KASSERT(mutex_owned(&sc->lock));

       error = 0;
       switch(b->timing.op) {
       case TMR_WAIT_REL:
               seq_timer_waitabs(sc,
                   b->t_WAIT_REL.divisions + t->divs_lastevent);
               break;
       case TMR_WAIT_ABS:
               seq_timer_waitabs(sc, b->t_WAIT_ABS.divisions);
               break;
       case TMR_START:
               microtime(&t->reftime);
               t->divs_lastevent = t->divs_lastchange = 0;
               t->running = 1;
               break;
       case TMR_STOP:
               microtime(&t->stoptime);
               t->running = 0;
               break;
       case TMR_CONTINUE:
               if (t->running)
                       break;
               microtime(&when);
               SUBTIMEVAL(&when, &t->stoptime);
               ADDTIMEVAL(&t->reftime, &when);
               t->running = 1;
               break;
       case TMR_TEMPO:
               /* bpm is unambiguously MIDI clocks per minute / 24 */
               /* (24 MIDI clocks are usually but not always a quarter note) */
               if (b->t_TEMPO.bpm < 8) /* where are these limits specified? */
                       t->tempo_beatpermin = 8;
               else if (b->t_TEMPO.bpm > 360) /* ? */
                       t->tempo_beatpermin = 360;
               else
                       t->tempo_beatpermin = b->t_TEMPO.bpm;
               t->divs_lastchange = t->divs_lastevent;
               microtime(&t->reftime);
               RECALC_USPERDIV(t);
               break;
       case TMR_ECHO:
               error = seq_input_event(sc, b);
               break;
       case TMR_RESET:
               t->divs_lastevent = t->divs_lastchange = 0;
               microtime(&t->reftime);
               break;
       case TMR_SPP:
       case TMR_TIMESIG:
               DPRINTF(("%s: unimplemented %02x\n", __func__, b->timing.op));
               error = EINVAL; /* not quite accurate... */
               break;
       default:
               DPRINTF(("%s: unknown %02x\n", __func__, b->timing.op));
               error = EINVAL;
               break;
       }
       return error;
}

static int
seq_do_fullsize(struct sequencer_softc *sc, seq_event_t *b, struct uio *uio)
{
       struct sysex_info sysex;
       u_int dev;

       CTASSERT(sizeof(seq_event_rec) == SEQ_SYSEX_HDRSIZE);
       memcpy(&sysex, b, sizeof(*b));
       dev = sysex.device_no;
       if (/* dev < 0 || */ dev >= sc->nmidi)
               return ENXIO;
       DPRINTFN(2, ("seq_do_fullsize: fmt=%04x, dev=%d, len=%d\n",
                    sysex.key, dev, sysex.len));
       return midiseq_loadpatch(sc->devs[dev], &sysex, uio);
}

/*
* Convert an old sequencer event to a new one.
* NOTE: on entry, *ev may contain valid data only in the first 4 bytes.
* That may be true even on exit (!) in the case of SEQOLD_MIDIPUTC; the
* caller will only look at the first bytes in that case anyway. Ugly? Sure.
*/
static int
seq_to_new(seq_event_t *ev, struct uio *uio)
{
       int cmd, chan, note, parm;
       uint32_t tmp_delay;
       int error;
       uint8_t *bfp;

       cmd = ev->tag;
       bfp = ev->unknown.byte;
       chan = *bfp++;
       note = *bfp++;
       parm = *bfp++;
       DPRINTFN(3, ("seq_to_new: 0x%02x %d %d %d\n", cmd, chan, note, parm));

       if (cmd >= 0x80) {
               /* Fill the event record */
               if (uio->uio_resid >= sizeof *ev - SEQOLD_CMDSIZE) {
                       error = uiomove(bfp, sizeof *ev - SEQOLD_CMDSIZE, uio);
                       if (error)
                               return error;
               } else
                       return EINVAL;
       }

       switch(cmd) {
       case SEQOLD_NOTEOFF:
               /*
                * What's with the SEQ_NOTE_XXX?  In OSS this seems to have
                * been undocumented magic for messing with the overall volume
                * of a 'voice', equated precariously with 'channel' and
                * pretty much unimplementable except by directly frobbing a
                * synth chip. For us, who treat everything as interfaced over
                * MIDI, this will just be unceremoniously discarded as
                * invalid in midiseq_noteoff, making the whole event an
                * elaborate no-op, and that doesn't seem to be any different
                * from what happens on linux with a MIDI-interfaced device,
                * by the way. The moral is ... use the new /dev/music API, ok?
                */
               *ev = SEQ_MK_CHN(NOTEOFF, .device=0, .channel=chan,
                   .key=SEQ_NOTE_XXX, .velocity=parm);
               break;
       case SEQOLD_NOTEON:
               *ev = SEQ_MK_CHN(NOTEON,
                   .device=0, .channel=chan, .key=note, .velocity=parm);
               break;
       case SEQOLD_WAIT:
               /*
                * This event cannot even /exist/ on non-littleendian machines,
                * and so help me, that's exactly the way OSS defined it.
                * Also, the OSS programmer's guide states (p. 74, v1.11)
                * that seqold time units are system clock ticks, unlike
                * the new 'divisions' which are determined by timebase. In
                * that case we would need to do scaling here - but no such
                * behavior is visible in linux either--which also treats this
                * value, surprisingly, as an absolute, not relative, time.
                * My guess is that this event has gone unused so long that
                * nobody could agree we got it wrong no matter what we do.
                */
               tmp_delay = *(uint32_t *)ev >> 8;
               *ev = SEQ_MK_TIMING(WAIT_ABS, .divisions=tmp_delay);
               break;
       case SEQOLD_SYNCTIMER:
               /*
                * The TMR_RESET event is not defined in any OSS materials
                * I can find; it may have been invented here just to provide
                * an accurate _to_new translation of this event.
                */
               *ev = SEQ_MK_TIMING(RESET);
               break;
       case SEQOLD_PGMCHANGE:
               *ev = SEQ_MK_CHN(PGM_CHANGE,
                   .device=0, .channel=chan, .program=note);
               break;
       case SEQOLD_MIDIPUTC:
               break;          /* interpret in normal mode */
       case SEQOLD_ECHO:
       case SEQOLD_PRIVATE:
       case SEQOLD_EXTENDED:
       default:
               DPRINTF(("%s: not impl 0x%02x\n", __func__, cmd));
               return EINVAL;
       /* In case new-style events show up */
       case SEQ_TIMING:
       case SEQ_CHN_VOICE:
       case SEQ_CHN_COMMON:
       case SEQ_FULLSIZE:
               break;
       }
       return 0;
}

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

void
midiseq_in(struct midi_dev *md, u_char *msg, int len)
{
       struct sequencer_softc *sc;
       sequencer_pcqitem_t qi;

       DPRINTFN(2, ("midiseq_in: %p %02x %02x %02x\n",
                    md, msg[0], msg[1], msg[2]));

       sc = md->seq;

       qi.qi_msg[0] = msg[0];
       qi.qi_msg[1] = msg[1];
       qi.qi_msg[2] = msg[2];
       qi.qi_msg[3] = md->unit | 0x80; /* ensure non-zero value of qi_ptr */
       pcq_put(sc->pcq, qi.qi_ptr);
       softint_schedule(sc->sih);
}

static struct midi_dev *
midiseq_open(int unit, int flags)
{
       int error;
       struct midi_dev *md;
       struct midi_softc *sc;
       struct midi_info mi;
       int major;
       dev_t dev;
       vnode_t *vp;
       int oflags;

       major = devsw_name2chr("midi", NULL, 0);
       dev = makedev(major, unit);

       DPRINTFN(2, ("midiseq_open: %d %d\n", unit, flags));

       error = cdevvp(dev, &vp);
       if (error)
               return NULL;
       vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
       error = VOP_OPEN(vp, flags, kauth_cred_get());
       VOP_UNLOCK(vp);
       if (error) {
               vrele(vp);
               return NULL;
       }

       /* Only after we have acquired reference via VOP_OPEN(). */
       midi_getinfo(dev, &mi);
       oflags = flags;
       if ((mi.props & MIDI_PROP_CAN_INPUT) == 0)
               flags &= ~FREAD;
       if ((flags & (FREAD|FWRITE)) == 0) {
               vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
               VOP_CLOSE(vp, oflags, kauth_cred_get());
               VOP_UNLOCK(vp);
               vrele(vp);
               return NULL;
       }

       sc = device_lookup_private(&midi_cd, unit);
       md = kmem_zalloc(sizeof(*md), KM_SLEEP);
       md->unit = unit;
       md->name = mi.name;
       md->subtype = 0;
       md->nr_voices = 128;    /* XXX */
       md->instr_bank_size = 128; /* XXX */
       md->vp = vp;
       if (mi.props & MIDI_PROP_CAN_INPUT)
               md->capabilities |= SYNTH_CAP_INPUT;
       sc->seq_md = md;
       return md;
}

static void
midiseq_close(struct midi_dev *md)
{

       DPRINTFN(2, ("midiseq_close: %d\n", md->unit));
       (void)vn_close(md->vp, 0, kauth_cred_get());
       kmem_free(md, sizeof(*md));
}

static void
midiseq_reset(struct midi_dev *md)
{
       /* XXX send GM reset? */
       DPRINTFN(3, ("midiseq_reset: %d\n", md->unit));
}

static int
midiseq_out(struct midi_dev *md, u_char *bf, u_int cc, int chk)
{
       DPRINTFN(5, ("midiseq_out: md=%p, unit=%d, bf[0]=0x%02x, cc=%d\n",
                    md, md->unit, bf[0], cc));

       /* midi(4) does running status compression where appropriate. */
       return midi_writebytes(md->unit, bf, cc);
}

/*
* If the writing process hands us a hidden note-off in a note-on event,
* we will simply write it that way; no need to special case it here,
* as midi(4) will always canonicalize or compress as appropriate anyway.
*/
static int
midiseq_noteon(struct midi_dev *md, int chan, int key, seq_event_t *ev)
{

       return midiseq_out(md, (uint8_t[]){
           MIDI_NOTEON | chan, key, ev->c_NOTEON.velocity & 0x7f}, 3, 1);
}

static int
midiseq_noteoff(struct midi_dev *md, int chan, int key, seq_event_t *ev)
{

       return midiseq_out(md, (uint8_t[]){
           MIDI_NOTEOFF | chan, key, ev->c_NOTEOFF.velocity & 0x7f}, 3, 1);
}

static int
midiseq_keypressure(struct midi_dev *md, int chan, int key, seq_event_t *ev)
{

       return midiseq_out(md, (uint8_t[]){
           MIDI_KEY_PRESSURE | chan, key,
           ev->c_KEY_PRESSURE.pressure & 0x7f}, 3, 1);
}

static int
midiseq_pgmchange(struct midi_dev *md, int chan, seq_event_t *ev)
{

       if (ev->c_PGM_CHANGE.program > 127)
               return EINVAL;
       return midiseq_out(md, (uint8_t[]){
           MIDI_PGM_CHANGE | chan, ev->c_PGM_CHANGE.program}, 2, 1);
}

static int
midiseq_chnpressure(struct midi_dev *md, int chan, seq_event_t *ev)
{

       if (ev->c_CHN_PRESSURE.pressure > 127)
               return EINVAL;
       return midiseq_out(md, (uint8_t[]){
           MIDI_CHN_PRESSURE | chan, ev->c_CHN_PRESSURE.pressure}, 2, 1);
}

static int
midiseq_ctlchange(struct midi_dev *md, int chan, seq_event_t *ev)
{

       if (ev->c_CTL_CHANGE.controller > 127)
               return EINVAL;
       return midiseq_out( md, (uint8_t[]){
           MIDI_CTL_CHANGE | chan, ev->c_CTL_CHANGE.controller,
           ev->c_CTL_CHANGE.value & 0x7f /* XXX this is SO wrong */
           }, 3, 1);
}

static int
midiseq_pitchbend(struct midi_dev *md, int chan, seq_event_t *ev)
{

       return midiseq_out(md, (uint8_t[]){
           MIDI_PITCH_BEND | chan,
           ev->c_PITCH_BEND.value & 0x7f,
           (ev->c_PITCH_BEND.value >> 7) & 0x7f}, 3, 1);
}

static int
midiseq_loadpatch(struct midi_dev *md,
                 struct sysex_info *sysex, struct uio *uio)
{
       struct sequencer_softc *sc;
       u_char c, bf[128];
       int i, cc, error;

       if (sysex->key != SEQ_SYSEX_PATCH) {
               DPRINTFN(-1,("midiseq_loadpatch: bad patch key 0x%04x\n",
                            sysex->key));
               return EINVAL;
       }
       if (uio->uio_resid < sysex->len)
               /* adjust length, should be an error */
               sysex->len = uio->uio_resid;

       DPRINTFN(2, ("midiseq_loadpatch: len=%d\n", sysex->len));
       if (sysex->len == 0)
               return EINVAL;
       error = uiomove(&c, 1, uio);
       if (error)
               return error;
       if (c != MIDI_SYSEX_START)              /* must start like this */
               return EINVAL;
       sc = md->seq;
       mutex_enter(&sc->lock);
       error = midiseq_out(md, &c, 1, 0);
       mutex_exit(&sc->lock);
       if (error)
               return error;
       --sysex->len;
       while (sysex->len > 0) {
               cc = sysex->len;
               if (cc > sizeof bf)
                       cc = sizeof bf;
               error = uiomove(bf, cc, uio);
               if (error)
                       break;
               for(i = 0; i < cc && !MIDI_IS_STATUS(bf[i]); i++)
                       ;
               /*
                * XXX midi(4)'s buffer might not accommodate this, and the
                * function will not block us (though in this case we have
                * a process and could in principle block).
                */
               mutex_enter(&sc->lock);
               error = midiseq_out(md, bf, i, 0);
               mutex_exit(&sc->lock);
               if (error)
                       break;
               sysex->len -= i;
               if (i != cc)
                       break;
       }
       /*
        * Any leftover data in uio is rubbish;
        * the SYSEX should be one write ending in SYSEX_END.
        */
       uio->uio_resid = 0;
       c = MIDI_SYSEX_END;
       mutex_enter(&sc->lock);
       error = midiseq_out(md, &c, 1, 0);
       mutex_exit(&sc->lock);
       return error;
}

#if NMIDI == 0
static dev_type_open(midiopen);
static dev_type_close(midiclose);

/*
* If someone has a sequencer, but no midi devices there will
* be unresolved references, so we provide little stubs.
*/

int
midi_unit_count(void)
{
       return 0;
}

static int
midiopen(dev_t dev, int flags, int ifmt, struct lwp *l)
{
       return ENXIO;
}

void
midi_getinfo(dev_t dev, struct midi_info *mi)
{
       mi->name = "Dummy MIDI device";
       mi->props = 0;
}

static int
midiclose(dev_t dev, int flags, int ifmt, struct lwp *l)
{
       return ENXIO;
}

int
midi_writebytes(int unit, u_char *bf, int cc)
{
       return ENXIO;
}
#endif /* NMIDI == 0 */