xref: /netbsd-src/sys/dev/midi.c (revision ce2c90c7c172d95d2402a5b3d96d8f8e6d138a21)
1 /*	$NetBSD: midi.c,v 1.49 2006/10/12 04:32:34 thorpej Exp $	*/
2 
3 /*
4  * Copyright (c) 1998 The NetBSD Foundation, Inc.
5  * All rights reserved.
6  *
7  * This code is derived from software contributed to The NetBSD Foundation
8  * by Lennart Augustsson (augustss@NetBSD.org) and (MIDI FST and Active
9  * Sense handling) Chapman Flack (chap@NetBSD.org).
10  *
11  * Redistribution and use in source and binary forms, with or without
12  * modification, are permitted provided that the following conditions
13  * are met:
14  * 1. Redistributions of source code must retain the above copyright
15  *    notice, this list of conditions and the following disclaimer.
16  * 2. Redistributions in binary form must reproduce the above copyright
17  *    notice, this list of conditions and the following disclaimer in the
18  *    documentation and/or other materials provided with the distribution.
19  * 3. All advertising materials mentioning features or use of this software
20  *    must display the following acknowledgement:
21  *        This product includes software developed by the NetBSD
22  *        Foundation, Inc. and its contributors.
23  * 4. Neither the name of The NetBSD Foundation nor the names of its
24  *    contributors may be used to endorse or promote products derived
25  *    from this software without specific prior written permission.
26  *
27  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
28  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
29  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
30  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
31  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
32  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
33  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
34  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
35  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
36  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
37  * POSSIBILITY OF SUCH DAMAGE.
38  */
39 
40 #include <sys/cdefs.h>
41 __KERNEL_RCSID(0, "$NetBSD: midi.c,v 1.49 2006/10/12 04:32:34 thorpej Exp $");
42 
43 #include "midi.h"
44 #include "sequencer.h"
45 
46 #include <sys/param.h>
47 #include <sys/ioctl.h>
48 #include <sys/fcntl.h>
49 #include <sys/vnode.h>
50 #include <sys/select.h>
51 #include <sys/poll.h>
52 #include <sys/malloc.h>
53 #include <sys/proc.h>
54 #include <sys/systm.h>
55 #include <sys/callout.h>
56 #include <sys/syslog.h>
57 #include <sys/kernel.h>
58 #include <sys/signalvar.h>
59 #include <sys/conf.h>
60 #include <sys/audioio.h>
61 #include <sys/midiio.h>
62 
63 #include <dev/audio_if.h>
64 #include <dev/midi_if.h>
65 #include <dev/midivar.h>
66 
67 #if NMIDI > 0
68 
69 #ifdef AUDIO_DEBUG
70 #define DPRINTF(x)	if (mididebug) printf x
71 #define DPRINTFN(n,x)	if (mididebug >= (n)) printf x
72 int	mididebug = 0;
73 /*
74  *      1: detected protocol errors and buffer overflows
75  *      2: probe, attach, detach
76  *      3: open, close
77  *      4: data received except realtime
78  *      5: ioctl
79  *      6: read, write, poll
80  *      7: data transmitted
81  *      8: uiomoves, synchronization
82  *      9: realtime data received
83  */
84 #else
85 #define DPRINTF(x)
86 #define DPRINTFN(n,x)
87 #endif
88 
89 static	struct simplelock hwif_register_lock = SIMPLELOCK_INITIALIZER;
90 static	struct midi_softc *hwif_softc = NULL;
91 
92 void	midi_in(void *, int);
93 void	midi_out(void *);
94 int     midi_poll_out(struct midi_softc *);
95 int     midi_intr_out(struct midi_softc *);
96 int 	midi_msg_out(struct midi_softc *,
97                  u_char **, u_char **, u_char **, u_char **);
98 int	midi_start_output(struct midi_softc *);
99 int	midi_sleep_timo(int *, const char *, int, struct simplelock *);
100 int	midi_sleep(int *, const char *, struct simplelock *);
101 void	midi_wakeup(int *);
102 void	midi_initbuf(struct midi_buffer *);
103 void	midi_xmt_asense(void *);
104 void	midi_rcv_asense(void *);
105 
106 int	midiprobe(struct device *, struct cfdata *, void *);
107 void	midiattach(struct device *, struct device *, void *);
108 int	mididetach(struct device *, int);
109 int	midiactivate(struct device *, enum devact);
110 
111 dev_type_open(midiopen);
112 dev_type_close(midiclose);
113 dev_type_read(midiread);
114 dev_type_write(midiwrite);
115 dev_type_ioctl(midiioctl);
116 dev_type_poll(midipoll);
117 dev_type_kqfilter(midikqfilter);
118 
119 const struct cdevsw midi_cdevsw = {
120 	midiopen, midiclose, midiread, midiwrite, midiioctl,
121 	nostop, notty, midipoll, nommap, midikqfilter, D_OTHER,
122 };
123 
124 CFATTACH_DECL(midi, sizeof(struct midi_softc),
125     midiprobe, midiattach, mididetach, midiactivate);
126 
127 #define MIDI_XMT_ASENSE_PERIOD mstohz(275)
128 #define MIDI_RCV_ASENSE_PERIOD mstohz(300)
129 
130 extern struct cfdriver midi_cd;
131 
132 int
133 midiprobe(struct device *parent __unused, struct cfdata *match __unused,
134     void *aux)
135 {
136 	struct audio_attach_args *sa = aux;
137 
138 	DPRINTFN(2,("midiprobe: type=%d sa=%p hw=%p\n",
139 		 sa->type, sa, sa->hwif));
140 	return (sa->type == AUDIODEV_TYPE_MIDI);
141 }
142 
143 void
144 midiattach(struct device *parent, struct device *self, void *aux)
145 {
146 	struct midi_softc *sc = (void *)self;
147 	struct audio_attach_args *sa = aux;
148 	const struct midi_hw_if *hwp = sa->hwif;
149 	void *hdlp = sa->hdl;
150 
151 	DPRINTFN(2, ("MIDI attach\n"));
152 
153 #ifdef DIAGNOSTIC
154 	if (hwp == 0 ||
155 	    hwp->open == 0 ||
156 	    hwp->close == 0 ||
157 	    hwp->output == 0 ||
158 	    hwp->getinfo == 0) {
159 		printf("midi: missing method\n");
160 		return;
161 	}
162 #endif
163 
164 	sc->hw_if = hwp;
165 	sc->hw_hdl = hdlp;
166 	midi_attach(sc, parent);
167 }
168 
169 int
170 midiactivate(struct device *self, enum devact act)
171 {
172 	struct midi_softc *sc = (struct midi_softc *)self;
173 
174 	switch (act) {
175 	case DVACT_ACTIVATE:
176 		return (EOPNOTSUPP);
177 
178 	case DVACT_DEACTIVATE:
179 		sc->dying = 1;
180 		break;
181 	}
182 	return (0);
183 }
184 
185 int
186 mididetach(struct device *self, int flags __unused)
187 {
188 	struct midi_softc *sc = (struct midi_softc *)self;
189 	int maj, mn;
190 
191 	DPRINTFN(2,("midi_detach: sc=%p flags=%d\n", sc, flags));
192 
193 	sc->dying = 1;
194 
195 	wakeup(&sc->wchan);
196 	wakeup(&sc->rchan);
197 
198 	/* locate the major number */
199 	maj = cdevsw_lookup_major(&midi_cdevsw);
200 
201 	/* Nuke the vnodes for any open instances (calls close). */
202 	mn = device_unit(self);
203 	vdevgone(maj, mn, mn, VCHR);
204 
205 	if ( !(sc->props & MIDI_PROP_NO_OUTPUT) ) {
206 		evcnt_detach(&sc->xmt.bytesDiscarded);
207 		evcnt_detach(&sc->xmt.incompleteMessages);
208 	}
209 	if ( sc->props & MIDI_PROP_CAN_INPUT ) {
210 		evcnt_detach(&sc->rcv.bytesDiscarded);
211 		evcnt_detach(&sc->rcv.incompleteMessages);
212 	}
213 
214 	return (0);
215 }
216 
217 void
218 midi_attach(struct midi_softc *sc, struct device *parent)
219 {
220 	struct midi_info mi;
221 	int s;
222 
223 	callout_init(&sc->xmt_asense_co);
224 	callout_init(&sc->rcv_asense_co);
225 	callout_setfunc(&sc->xmt_asense_co, midi_xmt_asense, sc);
226 	callout_setfunc(&sc->rcv_asense_co, midi_rcv_asense, sc);
227 	simple_lock_init(&sc->out_lock);
228 	simple_lock_init(&sc->in_lock);
229 	sc->dying = 0;
230 	sc->isopen = 0;
231 
232 	sc->sc_dev = parent;
233 
234 	s = splaudio();
235 	simple_lock(&hwif_register_lock);
236 	hwif_softc = sc;
237 	sc->hw_if->getinfo(sc->hw_hdl, &mi);
238 	hwif_softc = NULL;
239 	simple_unlock(&hwif_register_lock);
240 	splx(s);
241 
242 	sc->props = mi.props;
243 
244 	if ( !(sc->props & MIDI_PROP_NO_OUTPUT) ) {
245 		evcnt_attach_dynamic(&sc->xmt.bytesDiscarded,
246 			EVCNT_TYPE_MISC, NULL,
247 			sc->dev.dv_xname, "xmt bytes discarded");
248 		evcnt_attach_dynamic(&sc->xmt.incompleteMessages,
249 			EVCNT_TYPE_MISC, NULL,
250 			sc->dev.dv_xname, "xmt incomplete msgs");
251 	}
252 	if ( sc->props & MIDI_PROP_CAN_INPUT ) {
253 		evcnt_attach_dynamic(&sc->rcv.bytesDiscarded,
254 			EVCNT_TYPE_MISC, NULL,
255 			sc->dev.dv_xname, "rcv bytes discarded");
256 		evcnt_attach_dynamic(&sc->rcv.incompleteMessages,
257 			EVCNT_TYPE_MISC, NULL,
258 			sc->dev.dv_xname, "rcv incomplete msgs");
259 	}
260 
261 	printf(": %s%s\n", mi.name,
262 	    (sc->props & (MIDI_PROP_OUT_INTR|MIDI_PROP_NO_OUTPUT)) ?
263 	    "" : " (CPU-intensive output)");
264 }
265 
266 void midi_register_hw_if_ext(struct midi_hw_if_ext *exthw) {
267 	if ( hwif_softc != NULL ) /* ignore calls resulting from non-init */
268 		hwif_softc->hw_if_ext = exthw; /* uses of getinfo */
269 }
270 
271 int
272 midi_unit_count(void)
273 {
274 	int i;
275 	for ( i = 0; i < midi_cd.cd_ndevs; ++i )
276 	        if ( NULL == midi_cd.cd_devs[i] )
277 		        break;
278         return i;
279 }
280 
281 void
282 midi_initbuf(struct midi_buffer *mb)
283 {
284 	mb->idx_producerp = mb->idx_consumerp = mb->idx;
285 	mb->buf_producerp = mb->buf_consumerp = mb->buf;
286 }
287 #define PACK_MB_IDX(cat,len) (((cat)<<4)|(len))
288 #define MB_IDX_CAT(idx) ((idx)>>4)
289 #define MB_IDX_LEN(idx) ((idx)&0xf)
290 
291 int
292 midi_sleep_timo(int *chan, const char *label, int timo, struct simplelock *lk)
293 {
294 	int st;
295 
296 	if (!label)
297 		label = "midi";
298 
299 	DPRINTFN(8, ("midi_sleep_timo: %p %s %d\n", chan, label, timo));
300 	*chan = 1;
301 	st = ltsleep(chan, PWAIT | PCATCH, label, timo, lk);
302 	*chan = 0;
303 #ifdef MIDI_DEBUG
304 	if (st != 0)
305 		printf("midi_sleep: %d\n", st);
306 #endif
307 	return st;
308 }
309 
310 int
311 midi_sleep(int *chan, const char *label, struct simplelock *lk)
312 {
313 	return midi_sleep_timo(chan, label, 0, lk);
314 }
315 
316 void
317 midi_wakeup(int *chan)
318 {
319 	if (*chan) {
320 		DPRINTFN(8, ("midi_wakeup: %p\n", chan));
321 		wakeup(chan);
322 		*chan = 0;
323 	}
324 }
325 
326 /* in midivar.h:
327 #define MIDI_CAT_DATA 0
328 #define MIDI_CAT_STATUS1 1
329 #define MIDI_CAT_STATUS2 2
330 #define MIDI_CAT_COMMON 3
331 */
332 static char const midi_cats[] = "\0\0\0\0\0\0\0\0\2\2\2\2\1\1\2\3";
333 #define MIDI_CAT(d) (midi_cats[((d)>>4)&15])
334 #define FST_RETURN(offp,endp,ret) \
335 	return (s->pos=s->msg+(offp)), (s->end=s->msg+(endp)), (ret)
336 
337 enum fst_ret { FST_CHN, FST_CHV, FST_COM, FST_SYX, FST_RT, FST_MORE, FST_ERR,
338                FST_HUH, FST_SXP };
339 enum fst_form { FST_CANON, FST_COMPR, FST_VCOMP };
340 static struct {
341 	int off;
342 	enum fst_ret tag;
343 } const midi_forms[] = {
344 	[FST_CANON] = { .off=0, .tag=FST_CHN },
345 	[FST_COMPR] = { .off=1, .tag=FST_CHN },
346 	[FST_VCOMP] = { .off=0, .tag=FST_CHV }
347 };
348 #define FST_CRETURN(endp) \
349 	FST_RETURN(midi_forms[form].off,endp,midi_forms[form].tag)
350 
351 /*
352  * A MIDI finite state transducer suitable for receiving or transmitting. It
353  * will accept correct MIDI input that uses, doesn't use, or sometimes uses the
354  * 'running status' compression technique, and transduce it to fully expanded
355  * (form=FST_CANON) or fully compressed (form=FST_COMPR or FST_VCOMP) form.
356  *
357  * Returns FST_MORE if a complete message has not been parsed yet (SysEx
358  * messages are the exception), FST_ERR or FST_HUH if the input does not
359  * conform to the protocol, or FST_CHN (channel messages), FST_COM (System
360  * Common messages), FST_RT (System Real-Time messages), or FST_SYX (System
361  * Exclusive) to broadly categorize the message parsed. s->pos and s->end
362  * locate the parsed message; while (s->pos<s->end) putchar(*(s->pos++));
363  * would output it.
364  *
365  * FST_HUH means the character c wasn't valid in the original state, but the
366  * state has now been reset to START and the caller should try again passing
367  * the same c. FST_ERR means c isn't valid in the start state; the caller
368  * should kiss it goodbye and continue to try successive characters from the
369  * input until something other than FST_ERR or FST_HUH is returned, at which
370  * point things are resynchronized.
371  *
372  * A FST_SYX return means that between pos and end are from 1 to 3
373  * bytes of a system exclusive message. A SysEx message will be delivered in
374  * one or more chunks of that form, where the first begins with 0xf0 and the
375  * last (which is the only one that might have length < 3) ends with 0xf7.
376  *
377  * Messages corrupted by a protocol error are discarded and won't be seen at
378  * all; again SysEx is the exception, as one or more chunks of it may already
379  * have been parsed.
380  *
381  * For FST_CHN messages, s->msg[0] always contains the status byte even if
382  * FST_COMPR form was requested (pos then points to msg[1]). That way, the
383  * caller can always identify the exact message if there is a need to do so.
384  * For all other message types except FST_SYX, the status byte is at *pos
385  * (which may not necessarily be msg[0]!). There is only one SysEx status
386  * byte, so the return value FST_SYX is sufficient to identify it.
387  *
388  * To simplify some use cases, compression can also be requested with
389  * form=FST_VCOMP. In this form a compressible channel message is indicated
390  * by returning a classification of FST_CHV instead of FST_CHN, and pos points
391  * to the status byte rather than being advanced past it. If the caller in this
392  * case saves the bytes from pos to end, it will have saved the entire message,
393  * and can act on the FST_CHV tag to drop the first byte later. In this form,
394  * unlike FST_CANON, hidden note-off (i.e. note-on with velocity 0) may occur.
395  *
396  * Two obscure points in the MIDI protocol complicate things further, both to
397  * do with the EndSysEx code, 0xf7. First, this code is permitted (and
398  * meaningless) outside of a System Exclusive message, anywhere a status byte
399  * could appear. Second, it is allowed to be absent at the end of a System
400  * Exclusive message (!) - any status byte at all (non-realtime) is allowed to
401  * terminate the message. Both require accomodation in the interface to
402  * midi_fst's caller. A stray 0xf7 should be ignored BUT should count as a
403  * message received for purposes of Active Sense timeout; the case is
404  * represented by a return of FST_COM with a length of zero (pos == end). A
405  * status byte other than 0xf7 during a system exclusive message will cause an
406  * FST_SXP (sysex plus) return; the bytes from pos to end are the end of the
407  * system exclusive message, and after handling those the caller should call
408  * midi_fst again with the same input byte.
409  *
410  * midi(4) will never produce either such form of rubbish.
411  */
412 static enum fst_ret
413 midi_fst(struct midi_state *s, u_char c, enum fst_form form)
414 {
415 	int syxpos = 0;
416 
417 	if ( c >= 0xf8 ) { /* All realtime messages bypass state machine */
418 	        if ( c == 0xf9  ||  c == 0xfd ) {
419 			DPRINTF( ("midi_fst: s=%p c=0x%02x undefined\n",
420 				  s, c));
421 			s->bytesDiscarded.ev_count++;
422 			return FST_ERR;
423 		}
424 		DPRINTFN(9, ("midi_fst: s=%p System Real-Time data=0x%02x\n",
425 			     s, c));
426 		s->msg[2] = c;
427 		FST_RETURN(2,3,FST_RT);
428 	}
429 
430 	DPRINTFN(4, ("midi_fst: s=%p data=0x%02x state=%d\n",
431 		     s, c, s->state));
432 
433         switch ( s->state   | MIDI_CAT(c) ) { /* break ==> return FST_MORE */
434 
435 	case MIDI_IN_START  | MIDI_CAT_COMMON:
436 	case MIDI_IN_RUN1_1 | MIDI_CAT_COMMON:
437 	case MIDI_IN_RUN2_2 | MIDI_CAT_COMMON:
438 	case MIDI_IN_RXX2_2 | MIDI_CAT_COMMON:
439 	        s->msg[0] = c;
440 	        switch ( c ) {
441 		case 0xf0: s->state = MIDI_IN_SYX1_3; break;
442 		case 0xf1: s->state = MIDI_IN_COM0_1; break;
443 		case 0xf2: s->state = MIDI_IN_COM0_2; break;
444 		case 0xf3: s->state = MIDI_IN_COM0_1; break;
445 		case 0xf6: s->state = MIDI_IN_START;  FST_RETURN(0,1,FST_COM);
446 		case 0xf7: s->state = MIDI_IN_START;  FST_RETURN(0,0,FST_COM);
447 		default: goto protocol_violation;
448 		}
449 		break;
450 
451 	case MIDI_IN_RUN1_1 | MIDI_CAT_STATUS1:
452 		if ( c == s->msg[0] ) {
453 			s->state = MIDI_IN_RNX0_1;
454 			break;
455 		}
456 		/* FALLTHROUGH */
457 	case MIDI_IN_RUN2_2 | MIDI_CAT_STATUS1:
458 	case MIDI_IN_RXX2_2 | MIDI_CAT_STATUS1:
459 	case MIDI_IN_START  | MIDI_CAT_STATUS1:
460 	        s->state = MIDI_IN_RUN0_1;
461 	        s->msg[0] = c;
462 		break;
463 
464 	case MIDI_IN_RUN2_2 | MIDI_CAT_STATUS2:
465 	case MIDI_IN_RXX2_2 | MIDI_CAT_STATUS2:
466 		if ( c == s->msg[0] ) {
467 			s->state = MIDI_IN_RNX0_2;
468 			break;
469 		}
470 		if ( (c ^ s->msg[0]) == 0x10 && (c & 0xe0) == 0x80 ) {
471 			s->state = MIDI_IN_RXX0_2;
472 			s->msg[0] = c;
473 			break;
474 		}
475 		/* FALLTHROUGH */
476 	case MIDI_IN_RUN1_1 | MIDI_CAT_STATUS2:
477 	case MIDI_IN_START  | MIDI_CAT_STATUS2:
478 	        s->state = MIDI_IN_RUN0_2;
479 	        s->msg[0] = c;
480 		break;
481 
482         case MIDI_IN_COM0_1 | MIDI_CAT_DATA:
483 		s->state = MIDI_IN_START;
484 	        s->msg[1] = c;
485 		FST_RETURN(0,2,FST_COM);
486 
487         case MIDI_IN_COM0_2 | MIDI_CAT_DATA:
488 	        s->state = MIDI_IN_COM1_2;
489 	        s->msg[1] = c;
490 		break;
491 
492         case MIDI_IN_COM1_2 | MIDI_CAT_DATA:
493 		s->state = MIDI_IN_START;
494 	        s->msg[2] = c;
495 		FST_RETURN(0,3,FST_COM);
496 
497         case MIDI_IN_RUN0_1 | MIDI_CAT_DATA:
498 		s->state = MIDI_IN_RUN1_1;
499 	        s->msg[1] = c;
500 		FST_RETURN(0,2,FST_CHN);
501 
502         case MIDI_IN_RUN1_1 | MIDI_CAT_DATA:
503         case MIDI_IN_RNX0_1 | MIDI_CAT_DATA:
504 		s->state = MIDI_IN_RUN1_1;
505 	        s->msg[1] = c;
506 		FST_CRETURN(2);
507 
508         case MIDI_IN_RUN0_2 | MIDI_CAT_DATA:
509 	        s->state = MIDI_IN_RUN1_2;
510 	        s->msg[1] = c;
511 		break;
512 
513         case MIDI_IN_RUN1_2 | MIDI_CAT_DATA:
514 		if ( FST_CANON == form && 0 == c && (s->msg[0]&0xf0) == 0x90 ) {
515 			s->state = MIDI_IN_RXX2_2;
516 			s->msg[0] ^= 0x10;
517 			s->msg[2] = 64;
518 		} else {
519 			s->state = MIDI_IN_RUN2_2;
520 	        	s->msg[2] = c;
521 		}
522 		FST_RETURN(0,3,FST_CHN);
523 
524         case MIDI_IN_RUN2_2 | MIDI_CAT_DATA:
525 	        s->state = MIDI_IN_RNX1_2;
526 	        s->msg[1] = c;
527 		break;
528 
529         case MIDI_IN_RXX2_2 | MIDI_CAT_DATA:
530 	        s->state = MIDI_IN_RXX1_2;
531 		s->msg[0] ^= 0x10;
532 	        s->msg[1] = c;
533 		break;
534 
535         case MIDI_IN_RNX0_2 | MIDI_CAT_DATA:
536 	        s->state = MIDI_IN_RNY1_2;
537 	        s->msg[1] = c;
538 		break;
539 
540         case MIDI_IN_RXX0_2 | MIDI_CAT_DATA:
541 	        s->state = MIDI_IN_RXY1_2;
542 	        s->msg[1] = c;
543 		break;
544 
545         case MIDI_IN_RNX1_2 | MIDI_CAT_DATA:
546         case MIDI_IN_RNY1_2 | MIDI_CAT_DATA:
547 		if ( FST_CANON == form && 0 == c && (s->msg[0]&0xf0) == 0x90 ) {
548 			s->state = MIDI_IN_RXX2_2;
549 			s->msg[0] ^= 0x10;
550 			s->msg[2] = 64;
551 			FST_RETURN(0,3,FST_CHN);
552 		}
553 		s->state = MIDI_IN_RUN2_2;
554 	        s->msg[2] = c;
555 		FST_CRETURN(3);
556 
557         case MIDI_IN_RXX1_2 | MIDI_CAT_DATA:
558         case MIDI_IN_RXY1_2 | MIDI_CAT_DATA:
559 		if ( ( 0 == c && (s->msg[0]&0xf0) == 0x90)
560 		  || (64 == c && (s->msg[0]&0xf0) == 0x80
561 		      && FST_CANON != form) ) {
562 			s->state = MIDI_IN_RXX2_2;
563 			s->msg[0] ^= 0x10;
564 			s->msg[2] = 64 - c;
565 			FST_CRETURN(3);
566 		}
567 		s->state = MIDI_IN_RUN2_2;
568 	        s->msg[2] = c;
569 		FST_RETURN(0,3,FST_CHN);
570 
571         case MIDI_IN_SYX1_3 | MIDI_CAT_DATA:
572 		s->state = MIDI_IN_SYX2_3;
573 	        s->msg[1] = c;
574 		break;
575 
576         case MIDI_IN_SYX2_3 | MIDI_CAT_DATA:
577 		s->state = MIDI_IN_SYX0_3;
578 	        s->msg[2] = c;
579 		FST_RETURN(0,3,FST_SYX);
580 
581         case MIDI_IN_SYX0_3 | MIDI_CAT_DATA:
582 		s->state = MIDI_IN_SYX1_3;
583 	        s->msg[0] = c;
584 		break;
585 
586         case MIDI_IN_SYX2_3 | MIDI_CAT_COMMON:
587         case MIDI_IN_SYX2_3 | MIDI_CAT_STATUS1:
588         case MIDI_IN_SYX2_3 | MIDI_CAT_STATUS2:
589 		++ syxpos;
590 		/* FALLTHROUGH */
591         case MIDI_IN_SYX1_3 | MIDI_CAT_COMMON:
592         case MIDI_IN_SYX1_3 | MIDI_CAT_STATUS1:
593         case MIDI_IN_SYX1_3 | MIDI_CAT_STATUS2:
594 		++ syxpos;
595 		/* FALLTHROUGH */
596         case MIDI_IN_SYX0_3 | MIDI_CAT_COMMON:
597         case MIDI_IN_SYX0_3 | MIDI_CAT_STATUS1:
598         case MIDI_IN_SYX0_3 | MIDI_CAT_STATUS2:
599 		s->state = MIDI_IN_START;
600 	        if ( c == 0xf7 ) {
601 			s->msg[syxpos] = c;
602 		        FST_RETURN(0,1+syxpos,FST_SYX);
603 		}
604 		s->msg[syxpos] = 0xf7;
605 		FST_RETURN(0,1+syxpos,FST_SXP);
606 
607         default:
608 protocol_violation:
609                 DPRINTF(("midi_fst: unexpected %#02x in state %u\n",
610 		        c, s->state));
611 		switch ( s->state ) {
612 		case MIDI_IN_RUN1_1: /* can only get here by seeing an */
613 		case MIDI_IN_RUN2_2: /* INVALID System Common message */
614 		case MIDI_IN_RXX2_2:
615 		        s->state = MIDI_IN_START;
616 			/* FALLTHROUGH */
617 		case MIDI_IN_START:
618 			s->bytesDiscarded.ev_count++;
619 			return FST_ERR;
620 		case MIDI_IN_COM1_2:
621 		case MIDI_IN_RUN1_2:
622 		case MIDI_IN_RNY1_2:
623 		case MIDI_IN_RXY1_2:
624 			s->bytesDiscarded.ev_count++;
625 			/* FALLTHROUGH */
626 		case MIDI_IN_COM0_1:
627 		case MIDI_IN_RUN0_1:
628 		case MIDI_IN_RNX0_1:
629 		case MIDI_IN_COM0_2:
630 		case MIDI_IN_RUN0_2:
631 		case MIDI_IN_RNX0_2:
632 		case MIDI_IN_RXX0_2:
633 		case MIDI_IN_RNX1_2:
634 		case MIDI_IN_RXX1_2:
635 			s->bytesDiscarded.ev_count++;
636 		        s->incompleteMessages.ev_count++;
637 			break;
638 #if defined(AUDIO_DEBUG) || defined(DIAGNOSTIC)
639 		default:
640 		        printf("midi_fst: mishandled %#02x(%u) in state %u?!\n",
641 			      c, MIDI_CAT(c), s->state);
642 #endif
643 		}
644 		s->state = MIDI_IN_START;
645 		return FST_HUH;
646 	}
647 	return FST_MORE;
648 }
649 
650 void
651 midi_in(void *addr, int data)
652 {
653 	struct midi_softc *sc = addr;
654 	struct midi_buffer *mb = &sc->inbuf;
655 	int i;
656 	int count;
657 	enum fst_ret got;
658 	int s; /* hw may have various spls so impose our own */
659 	MIDI_BUF_DECLARE(idx);
660 	MIDI_BUF_DECLARE(buf);
661 
662 	if (!sc->isopen)
663 		return;
664 
665 	if (!(sc->flags & FREAD))
666 		return;		/* discard data if not reading */
667 
668 sxp_again:
669 	do
670 		got = midi_fst(&sc->rcv, data, FST_CANON);
671 	while ( got == FST_HUH );
672 
673 	switch ( got ) {
674 	case FST_MORE:
675 	case FST_ERR:
676 		return;
677 	case FST_CHN:
678 	case FST_COM:
679 	case FST_RT:
680 #if NSEQUENCER > 0
681 		if (sc->seqopen) {
682 			extern void midiseq_in(struct midi_dev *,u_char *,int);
683 			count = sc->rcv.end - sc->rcv.pos;
684 			midiseq_in(sc->seq_md, sc->rcv.pos, count);
685 			return;
686 		}
687 #endif
688         	/*
689 		 * Pass Active Sense to the sequencer if it's open, but not to
690 		 * a raw reader. (Really should do something intelligent with
691 		 * it then, though....)
692 		 */
693 		if ( got == FST_RT && MIDI_ACK == sc->rcv.pos[0] ) {
694 			if ( !sc->rcv_expect_asense ) {
695 				sc->rcv_expect_asense = 1;
696 				callout_schedule(&sc->rcv_asense_co,
697 				                 MIDI_RCV_ASENSE_PERIOD);
698 			}
699 			sc->rcv_quiescent = 0;
700 			sc->rcv_eof = 0;
701 			return;
702 		}
703 		/* FALLTHROUGH */
704 	/*
705 	 * Ultimately SysEx msgs should be offered to the sequencer also; the
706 	 * sequencer API addresses them - but maybe our sequencer can't handle
707 	 * them yet, so offer only to raw reader. (Which means, ultimately,
708 	 * discard them if the sequencer's open, as it's not doing reads!)
709 	 * -> When SysEx support is added to the sequencer, be sure to handle
710 	 *    FST_SXP there too.
711 	 */
712 	case FST_SYX:
713 	case FST_SXP:
714 		count = sc->rcv.end - sc->rcv.pos;
715 		MIDI_IN_LOCK(sc,s);
716 		sc->rcv_quiescent = 0;
717 		sc->rcv_eof = 0;
718 		if ( 0 == count ) {
719 			MIDI_IN_UNLOCK(sc,s);
720 			break;
721 		}
722 		MIDI_BUF_PRODUCER_INIT(mb,idx);
723 		MIDI_BUF_PRODUCER_INIT(mb,buf);
724 		if (count > buf_lim - buf_cur
725 		     || 1 > idx_lim - idx_cur) {
726 			sc->rcv.bytesDiscarded.ev_count += count;
727 			MIDI_IN_UNLOCK(sc,s);
728 			DPRINTF(("midi_in: buffer full, discard data=0x%02x\n",
729 				 sc->rcv.pos[0]));
730 			return;
731 		}
732 		for (i = 0; i < count; i++) {
733 			*buf_cur++ = sc->rcv.pos[i];
734 			MIDI_BUF_WRAP(buf);
735 		}
736 		*idx_cur++ = PACK_MB_IDX(got,count);
737 		MIDI_BUF_WRAP(idx);
738 		MIDI_BUF_PRODUCER_WBACK(mb,buf);
739 		MIDI_BUF_PRODUCER_WBACK(mb,idx);
740 		midi_wakeup(&sc->rchan);
741 		if (sc->async)
742 			psignal(sc->async, SIGIO);
743 		MIDI_IN_UNLOCK(sc,s);
744 		selnotify(&sc->rsel, 0); /* filter will spin if locked */
745 		break;
746 	default: /* don't #ifdef this away, gcc will say FST_HUH not handled */
747 		printf("midi_in: midi_fst returned %d?!\n", got);
748 	}
749 	if ( FST_SXP == got )
750 		goto sxp_again;
751 }
752 
753 void
754 midi_out(void *addr)
755 {
756 	struct midi_softc *sc = addr;
757 
758 	if (!sc->isopen)
759 		return;
760 	DPRINTFN(8, ("midi_out: %p\n", sc));
761 	midi_intr_out(sc);
762 }
763 
764 int
765 midiopen(dev_t dev, int flags, int ifmt __unused, struct lwp *l __unused)
766 {
767 	struct midi_softc *sc;
768 	const struct midi_hw_if *hw;
769 	int error;
770 
771 	sc = device_lookup(&midi_cd, MIDIUNIT(dev));
772 	if (sc == NULL)
773 		return (ENXIO);
774 	if (sc->dying)
775 		return (EIO);
776 
777 	DPRINTFN(3,("midiopen %p\n", sc));
778 
779 	hw = sc->hw_if;
780 	if (!hw)
781 		return ENXIO;
782 	if (sc->isopen)
783 		return EBUSY;
784 
785 	/* put both state machines into known states */
786 	sc->rcv.state = MIDI_IN_START;
787 	sc->rcv.pos = sc->rcv.msg;
788 	sc->rcv.end = sc->rcv.msg;
789 	sc->xmt.state = MIDI_IN_START;
790 	sc->xmt.pos = sc->xmt.msg;
791 	sc->xmt.end = sc->xmt.msg;
792 
793 	/* copy error counters so an ioctl (TBA) can give since-open stats */
794 	sc->rcv.atOpen.bytesDiscarded  = sc->rcv.bytesDiscarded.ev_count;
795 	sc->rcv.atQuery.bytesDiscarded = sc->rcv.bytesDiscarded.ev_count;
796 
797 	sc->xmt.atOpen.bytesDiscarded  = sc->xmt.bytesDiscarded.ev_count;
798 	sc->xmt.atQuery.bytesDiscarded = sc->xmt.bytesDiscarded.ev_count;
799 
800 	/* and the buffers */
801 	midi_initbuf(&sc->outbuf);
802 	midi_initbuf(&sc->inbuf);
803 
804 	/* and the receive flags */
805 	sc->rcv_expect_asense = 0;
806 	sc->rcv_quiescent = 0;
807 	sc->rcv_eof = 0;
808 
809 	error = hw->open(sc->hw_hdl, flags, midi_in, midi_out, sc);
810 	if (error)
811 		return error;
812 	sc->isopen++;
813 	sc->flags = flags;
814 	sc->rchan = 0;
815 	sc->wchan = 0;
816 	sc->pbus = 0;
817 	sc->async = 0;
818 
819 #ifdef MIDI_SAVE
820 	if (midicnt != 0) {
821 		midisave.cnt = midicnt;
822 		midicnt = 0;
823 	}
824 #endif
825 
826 	return 0;
827 }
828 
829 int
830 midiclose(dev_t dev, int flags __unused, int ifmt __unused,
831     struct lwp *l __unused)
832 {
833 	int unit = MIDIUNIT(dev);
834 	struct midi_softc *sc = midi_cd.cd_devs[unit];
835 	const struct midi_hw_if *hw = sc->hw_if;
836 	int s, error;
837 
838 	DPRINTFN(3,("midiclose %p\n", sc));
839 
840 	/* midi_start_output(sc); anything buffered => pbus already set! */
841 	error = 0;
842 	MIDI_OUT_LOCK(sc,s);
843 	while (sc->pbus) {
844 		DPRINTFN(8,("midiclose sleep ...\n"));
845 		error =
846 		midi_sleep_timo(&sc->wchan, "mid_dr", 30*hz, &sc->out_lock);
847 	}
848 	sc->isopen = 0;
849 	MIDI_OUT_UNLOCK(sc,s);
850 	callout_stop(&sc->xmt_asense_co); /* xxx fix this - sleep? */
851 	callout_stop(&sc->rcv_asense_co);
852 	hw->close(sc->hw_hdl);
853 #if NSEQUENCER > 0
854 	sc->seqopen = 0;
855 	sc->seq_md = 0;
856 #endif
857 	return 0;
858 }
859 
860 int
861 midiread(dev_t dev, struct uio *uio, int ioflag)
862 {
863 	int unit = MIDIUNIT(dev);
864 	struct midi_softc *sc = midi_cd.cd_devs[unit];
865 	struct midi_buffer *mb = &sc->inbuf;
866 	int error;
867 	int s;
868 	MIDI_BUF_DECLARE(idx);
869 	MIDI_BUF_DECLARE(buf);
870 	int appetite;
871 	int first = 1;
872 
873 	DPRINTFN(6,("midiread: %p, count=%lu\n", sc,
874 		 (unsigned long)uio->uio_resid));
875 
876 	if (sc->dying)
877 		return EIO;
878         if ( !(sc->props & MIDI_PROP_CAN_INPUT) )
879 	        return ENXIO;
880 
881 	MIDI_IN_LOCK(sc,s);
882 	MIDI_BUF_CONSUMER_INIT(mb,idx);
883 	MIDI_BUF_CONSUMER_INIT(mb,buf);
884 	MIDI_IN_UNLOCK(sc,s);
885 
886 	error = 0;
887 	for ( ;; ) {
888 		/*
889 		 * If the used portion of idx wraps around the end, just take
890 		 * the first part on this iteration, and we'll get the rest on
891 		 * the next.
892 		 */
893 		if ( idx_lim > idx_end )
894 			idx_lim = idx_end;
895 		/*
896 		 * Count bytes through the last complete message that will
897 		 * fit in the requested read.
898 		 */
899 		for (appetite = uio->uio_resid; idx_cur < idx_lim; ++idx_cur) {
900 			if ( appetite < MB_IDX_LEN(*idx_cur) )
901 				break;
902 			appetite -= MB_IDX_LEN(*idx_cur);
903 		}
904 		appetite = uio->uio_resid - appetite;
905 		/*
906 		 * Only if the read is too small to hold even the first
907 		 * complete message will we return a partial one (updating idx
908 		 * to reflect the remaining length of the message).
909 		 */
910 		if ( appetite == 0 && idx_cur < idx_lim ) {
911 			if ( !first )
912 				goto unlocked_exit; /* idx_cur not advanced */
913 			appetite = uio->uio_resid;
914 			*idx_cur = PACK_MB_IDX(MB_IDX_CAT(*idx_cur),
915 					       MB_IDX_LEN(*idx_cur) - appetite);
916 		}
917 		KASSERT(buf_cur + appetite <= buf_lim);
918 
919 		/* move the bytes */
920 		if ( appetite > 0 ) {
921 			first = 0;  /* we know we won't return empty-handed */
922 			/* do two uiomoves if data wrap around end of buf */
923 			if ( buf_cur + appetite > buf_end ) {
924 				DPRINTFN(8,
925 					("midiread: uiomove cc=%d (prewrap)\n",
926 					buf_end - buf_cur));
927 				error = uiomove(buf_cur, buf_end-buf_cur, uio);
928 				if ( error )
929 					goto unlocked_exit;
930 				appetite -= buf_end - buf_cur;
931 				buf_cur = mb->buf;
932 			}
933 			DPRINTFN(8, ("midiread: uiomove cc=%d\n", appetite));
934 			error = uiomove(buf_cur, appetite, uio);
935 			if ( error )
936 				goto unlocked_exit;
937 			buf_cur += appetite;
938 		}
939 
940 		MIDI_BUF_WRAP(idx);
941 		MIDI_BUF_WRAP(buf);
942 
943 		MIDI_IN_LOCK(sc,s);
944 		MIDI_BUF_CONSUMER_WBACK(mb,idx);
945 		MIDI_BUF_CONSUMER_WBACK(mb,buf);
946 		if ( 0 == uio->uio_resid ) /* if read satisfied, we're done */
947 			break;
948 		MIDI_BUF_CONSUMER_REFRESH(mb,idx);
949 		if ( idx_cur == idx_lim ) { /* need to wait for data? */
950 			if ( !first || sc->rcv_eof ) /* never block reader if */
951 				break;            /* any data already in hand */
952 			if (ioflag & IO_NDELAY) {
953 				error = EWOULDBLOCK;
954 				break;
955 			}
956 			error = midi_sleep(&sc->rchan, "mid rd", &sc->in_lock);
957 			if ( error )
958 				break;
959 			MIDI_BUF_CONSUMER_REFRESH(mb,idx); /* what'd we get? */
960 		}
961 		MIDI_BUF_CONSUMER_REFRESH(mb,buf);
962 		MIDI_IN_UNLOCK(sc,s);
963 		if ( sc->dying )
964 			return EIO;
965 	}
966 	MIDI_IN_UNLOCK(sc,s);
967 
968 unlocked_exit:
969 	return error;
970 }
971 
972 void
973 midi_rcv_asense(void *arg)
974 {
975 	struct midi_softc *sc = arg;
976 	int s;
977 
978 	if ( sc->dying || !sc->isopen )
979 		return;
980 
981 	if ( sc->rcv_quiescent ) {
982 		MIDI_IN_LOCK(sc,s);
983 		sc->rcv_eof = 1;
984 		sc->rcv_quiescent = 0;
985 		sc->rcv_expect_asense = 0;
986 		midi_wakeup(&sc->rchan);
987 		if (sc->async)
988 			psignal(sc->async, SIGIO);
989 		MIDI_IN_UNLOCK(sc,s);
990 		selnotify(&sc->rsel, 0); /* filter will spin if locked */
991 		return;
992 	}
993 
994 	sc->rcv_quiescent = 1;
995 	callout_schedule(&sc->rcv_asense_co, MIDI_RCV_ASENSE_PERIOD);
996 }
997 
998 void
999 midi_xmt_asense(void *arg)
1000 {
1001 	struct midi_softc *sc = arg;
1002 	int s;
1003 	int error;
1004 	int armed;
1005 
1006 	if ( sc->dying || !sc->isopen )
1007 		return;
1008 
1009 	MIDI_OUT_LOCK(sc,s);
1010 	if ( sc->pbus || sc->dying || !sc->isopen ) {
1011 		MIDI_OUT_UNLOCK(sc,s);
1012 		return;
1013 	}
1014 	sc->pbus = 1;
1015 	DPRINTFN(8,("midi_xmt_asense: %p\n", sc));
1016 
1017 	if ( sc->props & MIDI_PROP_OUT_INTR ) {
1018 		error = sc->hw_if->output(sc->hw_hdl, MIDI_ACK);
1019 		armed = (error == 0);
1020 	} else { /* polled output, do with interrupts unmasked */
1021 		MIDI_OUT_UNLOCK(sc,s);
1022 		/* running from softclock, so top half won't sneak in here */
1023 		error = sc->hw_if->output(sc->hw_hdl, MIDI_ACK);
1024 		MIDI_OUT_LOCK(sc,s);
1025 		armed = 0;
1026 	}
1027 
1028 	if ( !armed ) {
1029 		sc->pbus = 0;
1030 		callout_schedule(&sc->xmt_asense_co, MIDI_XMT_ASENSE_PERIOD);
1031 	}
1032 
1033 	MIDI_OUT_UNLOCK(sc,s);
1034 }
1035 
1036 /*
1037  * The way this function was hacked up to plug into poll_out and intr_out
1038  * after they were written won't win it any beauty contests, but it'll work
1039  * (code in haste, refactor at leisure). This may be called with the lock
1040  * (by intr_out) or without the lock (by poll_out) so it only does what could
1041  * be safe either way.
1042  */
1043 int midi_msg_out(struct midi_softc *sc,
1044                  u_char **idx, u_char **idxl, u_char **buf, u_char **bufl) {
1045 	MIDI_BUF_DECLARE(idx);
1046 	MIDI_BUF_DECLARE(buf);
1047 	MIDI_BUF_EXTENT_INIT(&sc->outbuf,idx);
1048 	MIDI_BUF_EXTENT_INIT(&sc->outbuf,buf);
1049 	int length;
1050 	int error;
1051 	u_char contig[3];
1052 	u_char *cp;
1053 	u_char *ep;
1054 
1055 	idx_cur = *idx;
1056 	idx_lim = *idxl;
1057 	buf_cur = *buf;
1058 	buf_lim = *bufl;
1059 
1060 	length = MB_IDX_LEN(*idx_cur);
1061 
1062 	for ( cp = contig, ep = cp + length; cp < ep; ) {
1063 		*cp++ = *buf_cur++;
1064 		MIDI_BUF_WRAP(buf);
1065 	}
1066 	cp = contig;
1067 
1068 	switch ( MB_IDX_CAT(*idx_cur) ) {
1069 	case FST_CHV: /* chnmsg to be compressed (for device that wants it) */
1070 		++ cp;
1071 		-- length;
1072 		/* FALLTHROUGH */
1073 	case FST_CHN:
1074 		error = sc->hw_if_ext->channel(sc->hw_hdl,
1075 		                               MIDI_GET_STATUS(contig[0]),
1076 					       MIDI_GET_CHAN(contig[0]),
1077 					       cp, length);
1078 		break;
1079 	case FST_COM:
1080 		error = sc->hw_if_ext->common(sc->hw_hdl,
1081 		                              MIDI_GET_STATUS(contig[0]),
1082 					      cp, length);
1083 		break;
1084 	case FST_SYX:
1085 	case FST_SXP:
1086 		error = sc->hw_if_ext->sysex(sc->hw_hdl,
1087 					     cp, length);
1088 		break;
1089 	case FST_RT:
1090 		error = sc->hw_if->output(sc->hw_hdl, *cp);
1091 		break;
1092 	default:
1093 		error = EIO;
1094 	}
1095 
1096 	if ( !error ) {
1097 		++ idx_cur;
1098 		MIDI_BUF_WRAP(idx);
1099 		*idx  = idx_cur;
1100 		*idxl = idx_lim;
1101 		*buf  = buf_cur;
1102 		*bufl = buf_lim;
1103 	}
1104 
1105 	return error;
1106 }
1107 
1108 /*
1109  * midi_poll_out is intended for the midi hw (the vast majority of MIDI UARTs
1110  * on sound cards, apparently) that _do not have transmit-ready interrupts_.
1111  * Every call to hw_if->output for one of these may busy-wait to output the
1112  * byte; at the standard midi data rate that'll be 320us per byte. The
1113  * technique of writing only MIDI_MAX_WRITE bytes in a row and then waiting
1114  * for MIDI_WAIT does not reduce the total time spent busy-waiting, and it
1115  * adds arbitrary delays in transmission (and, since MIDI_WAIT is roughly the
1116  * same as the time to send MIDI_MAX_WRITE bytes, it effectively halves the
1117  * data rate). Here, a somewhat bolder approach is taken. Since midi traffic
1118  * is bursty but time-sensitive--most of the time there will be none at all,
1119  * but when there is it should go out ASAP--the strategy is to just get it
1120  * over with, and empty the buffer in one go. The effect this can have on
1121  * the rest of the system will be limited by the size of the buffer and the
1122  * sparseness of the traffic. But some precautions are in order. Interrupts
1123  * should all be unmasked when this is called, and midiwrite should not fill
1124  * the buffer more than once (when MIDI_PROP_CAN_INTR is false) without a
1125  * yield() so some other process can get scheduled. If the write is nonblocking,
1126  * midiwrite should return a short count rather than yield.
1127  *
1128  * Someday when there is fine-grained MP support, this should be reworked to
1129  * run in a callout so the writing process really could proceed concurrently.
1130  * But obviously where performance is a concern, interrupt-driven hardware
1131  * such as USB midi or (apparently) clcs will always be preferable. And it
1132  * seems (kern/32651) that many of the devices currently working in poll mode
1133  * may really have tx interrupt capability and want only implementation; that
1134  * ought to happen.
1135  */
1136 int
1137 midi_poll_out(struct midi_softc *sc)
1138 {
1139 	struct midi_buffer *mb = &sc->outbuf;
1140 	int error;
1141 	int msglen;
1142 	int s;
1143 	MIDI_BUF_DECLARE(idx);
1144 	MIDI_BUF_DECLARE(buf);
1145 
1146 	error = 0;
1147 
1148 	MIDI_OUT_LOCK(sc,s);
1149 	MIDI_BUF_CONSUMER_INIT(mb,idx);
1150 	MIDI_BUF_CONSUMER_INIT(mb,buf);
1151 	MIDI_OUT_UNLOCK(sc,s);
1152 
1153 	for ( ;; ) {
1154 		while ( idx_cur != idx_lim ) {
1155 			if ( sc->hw_if_ext ) {
1156 				error = midi_msg_out(sc, &idx_cur, &idx_lim,
1157 				                         &buf_cur, &buf_lim);
1158 				if ( error )
1159 					goto ioerror;
1160 				continue;
1161 			}
1162 			/* or, lacking hw_if_ext ... */
1163 			msglen = MB_IDX_LEN(*idx_cur);
1164 			DPRINTFN(7,("midi_poll_out: %p <- %#02x\n",
1165 				   sc->hw_hdl, *buf_cur));
1166 			error = sc->hw_if->output(sc->hw_hdl, *buf_cur);
1167 			if ( error )
1168 				goto ioerror;
1169 			++ buf_cur;
1170 			MIDI_BUF_WRAP(buf);
1171 			-- msglen;
1172 			if ( msglen )
1173 				*idx_cur = PACK_MB_IDX(MB_IDX_CAT(*idx_cur),
1174 				                       msglen);
1175 			else {
1176 				++ idx_cur;
1177 				MIDI_BUF_WRAP(idx);
1178 			}
1179 		}
1180 		KASSERT(buf_cur == buf_lim);
1181 		MIDI_OUT_LOCK(sc,s);
1182 		MIDI_BUF_CONSUMER_WBACK(mb,idx);
1183 		MIDI_BUF_CONSUMER_WBACK(mb,buf);
1184 		MIDI_BUF_CONSUMER_REFRESH(mb,idx); /* any more to transmit? */
1185 		MIDI_BUF_CONSUMER_REFRESH(mb,buf);
1186 		if ( idx_lim == idx_cur )
1187 			break; /* still holding lock */
1188 		MIDI_OUT_UNLOCK(sc,s);
1189 	}
1190 	goto disarm; /* lock held */
1191 
1192 ioerror:
1193 #if defined(AUDIO_DEBUG) || defined(DIAGNOSTIC)
1194 	printf("%s: midi_poll_output error %d\n",
1195 	      sc->dev.dv_xname, error);
1196 #endif
1197 	MIDI_OUT_LOCK(sc,s);
1198 	MIDI_BUF_CONSUMER_WBACK(mb,idx);
1199 	MIDI_BUF_CONSUMER_WBACK(mb,buf);
1200 
1201 disarm:
1202 	sc->pbus = 0;
1203 	callout_schedule(&sc->xmt_asense_co, MIDI_XMT_ASENSE_PERIOD);
1204 	MIDI_OUT_UNLOCK(sc,s);
1205 	return error;
1206 }
1207 
1208 /*
1209  * The interrupt flavor acquires spl and lock once and releases at the end,
1210  * as it expects to write only one byte or message. The interface convention
1211  * is that if hw_if->output returns 0, it has initiated transmission and the
1212  * completion interrupt WILL be forthcoming; if it has not returned 0, NO
1213  * interrupt will be forthcoming, and if it returns EINPROGRESS it wants
1214  * another byte right away.
1215  */
1216 int
1217 midi_intr_out(struct midi_softc *sc)
1218 {
1219 	struct midi_buffer *mb = &sc->outbuf;
1220 	int error;
1221 	int msglen;
1222 	int s;
1223 	MIDI_BUF_DECLARE(idx);
1224 	MIDI_BUF_DECLARE(buf);
1225 	int armed = 0;
1226 
1227 	error = 0;
1228 
1229 	MIDI_OUT_LOCK(sc,s);
1230 	MIDI_BUF_CONSUMER_INIT(mb,idx);
1231 	MIDI_BUF_CONSUMER_INIT(mb,buf);
1232 
1233 	while ( idx_cur != idx_lim ) {
1234 		if ( sc->hw_if_ext ) {
1235 			error = midi_msg_out(sc, &idx_cur, &idx_lim,
1236 				                 &buf_cur, &buf_lim);
1237 			if ( !error ) /* no EINPROGRESS from extended hw_if */
1238 				armed = 1;
1239 			break;
1240 		}
1241 		/* or, lacking hw_if_ext ... */
1242 		msglen = MB_IDX_LEN(*idx_cur);
1243 		error = sc->hw_if->output(sc->hw_hdl, *buf_cur);
1244 		if ( error  &&  error != EINPROGRESS )
1245 			break;
1246 		++ buf_cur;
1247 		MIDI_BUF_WRAP(buf);
1248 		-- msglen;
1249 		if ( msglen )
1250 			*idx_cur = PACK_MB_IDX(MB_IDX_CAT(*idx_cur),msglen);
1251 		else {
1252 			++ idx_cur;
1253 			MIDI_BUF_WRAP(idx);
1254 		}
1255 		if ( !error ) {
1256 			armed = 1;
1257 			break;
1258 		}
1259 	}
1260 	MIDI_BUF_CONSUMER_WBACK(mb,idx);
1261 	MIDI_BUF_CONSUMER_WBACK(mb,buf);
1262 	if ( !armed ) {
1263 		sc->pbus = 0;
1264 		callout_schedule(&sc->xmt_asense_co, MIDI_XMT_ASENSE_PERIOD);
1265 	}
1266 	midi_wakeup(&sc->wchan);
1267 	if ( sc->async )
1268 		psignal(sc->async, SIGIO);
1269 	MIDI_OUT_UNLOCK(sc,s);
1270 	selnotify(&sc->wsel, 0); /* filter will spin if locked */
1271 
1272 #if defined(AUDIO_DEBUG) || defined(DIAGNOSTIC)
1273 	if ( error )
1274 		printf("%s: midi_intr_output error %d\n",
1275 	               sc->dev.dv_xname, error);
1276 #endif
1277 	return error;
1278 }
1279 
1280 int
1281 midi_start_output(struct midi_softc *sc)
1282 {
1283 	if (sc->dying)
1284 		return EIO;
1285 
1286 	if ( sc->props & MIDI_PROP_OUT_INTR )
1287 		return midi_intr_out(sc);
1288 	return midi_poll_out(sc);
1289 }
1290 
1291 static int
1292 real_writebytes(struct midi_softc *sc, u_char *ibuf, int cc)
1293 {
1294 	u_char *iend = ibuf + cc;
1295 	struct midi_buffer *mb = &sc->outbuf;
1296 	int arming = 0;
1297 	int count;
1298 	int s;
1299 	int got;
1300 	enum fst_form form;
1301 	MIDI_BUF_DECLARE(idx);
1302 	MIDI_BUF_DECLARE(buf);
1303 
1304 	/*
1305 	 * If the hardware uses the extended hw_if, pass it canonicalized
1306 	 * messages (or compressed ones if it specifically requests, using
1307 	 * VCOMP form so the bottom half can still pass the op and chan along);
1308 	 * if it does not, send it compressed messages (using COMPR form as
1309 	 * there is no need to preserve the status for the bottom half).
1310 	 */
1311 	if ( NULL == sc->hw_if_ext )
1312 		form = FST_COMPR;
1313 	else if ( sc->hw_if_ext->compress )
1314 		form = FST_VCOMP;
1315 	else
1316 		form = FST_CANON;
1317 
1318 	MIDI_OUT_LOCK(sc,s);
1319 	MIDI_BUF_PRODUCER_INIT(mb,idx);
1320 	MIDI_BUF_PRODUCER_INIT(mb,buf);
1321 	MIDI_OUT_UNLOCK(sc,s);
1322 
1323 	if (sc->dying)
1324 		return EIO;
1325 
1326 	while ( ibuf < iend ) {
1327 		got = midi_fst(&sc->xmt, *ibuf, form);
1328 		++ ibuf;
1329 		switch ( got ) {
1330 		case FST_MORE:
1331 			continue;
1332 		case FST_ERR:
1333 		case FST_HUH:
1334 			return EPROTO;
1335 		case FST_CHN:
1336 		case FST_CHV: /* only occurs in VCOMP form */
1337 		case FST_COM:
1338 		case FST_RT:
1339 		case FST_SYX:
1340 		case FST_SXP:
1341 			break; /* go add to buffer */
1342 #if defined(AUDIO_DEBUG) || defined(DIAGNOSTIC)
1343 		default:
1344 			printf("midi_wr: midi_fst returned %d?!\n", got);
1345 #endif
1346 		}
1347 		count = sc->xmt.end - sc->xmt.pos;
1348 		if ( 0 == count ) /* can happen with stray 0xf7; see midi_fst */
1349 			continue;
1350 		/*
1351 		 * return EWOULDBLOCK if the data passed will not fit in
1352 		 * the buffer; the caller should have taken steps to avoid that.
1353 		 * If got==FST_SXP we lose the new status byte, but we're losing
1354 		 * anyway, so c'est la vie.
1355 		 */
1356 		if ( idx_cur == idx_lim || count > buf_lim - buf_cur ) {
1357 			MIDI_OUT_LOCK(sc,s);
1358 			MIDI_BUF_PRODUCER_REFRESH(mb,idx); /* get the most */
1359 			MIDI_BUF_PRODUCER_REFRESH(mb,buf); /*  current facts */
1360 			MIDI_OUT_UNLOCK(sc,s);
1361 			if ( idx_cur == idx_lim || count > buf_lim - buf_cur )
1362 				return EWOULDBLOCK; /* caller's problem */
1363 		}
1364 		*idx_cur++ = PACK_MB_IDX(got,count);
1365 		MIDI_BUF_WRAP(idx);
1366 		while ( count ) {
1367 			*buf_cur++ = *(sc->xmt.pos)++;
1368 			MIDI_BUF_WRAP(buf);
1369 			-- count;
1370 		}
1371 		if ( FST_SXP == got )
1372 			-- ibuf; /* again with same status byte */
1373 	}
1374 	MIDI_OUT_LOCK(sc,s);
1375 	MIDI_BUF_PRODUCER_WBACK(mb,buf);
1376 	MIDI_BUF_PRODUCER_WBACK(mb,idx);
1377 	/*
1378 	 * If the output transfer is not already busy, and there is a message
1379 	 * buffered, mark it busy, stop the Active Sense callout (what if we're
1380 	 * too late and it's expired already? No big deal, an extra Active Sense
1381 	 * never hurt anybody) and start the output transfer once we're out of
1382 	 * the critical section (pbus==1 will stop anyone else doing the same).
1383 	 */
1384 	MIDI_BUF_CONSUMER_INIT(mb,idx); /* check what consumer's got to read */
1385 	if ( !sc->pbus && idx_cur < idx_lim ) {
1386 		sc->pbus = 1;
1387 		callout_stop(&sc->xmt_asense_co);
1388 		arming = 1;
1389 	}
1390 	MIDI_OUT_UNLOCK(sc,s);
1391 	return arming ? midi_start_output(sc) : 0;
1392 }
1393 
1394 int
1395 midiwrite(dev_t dev, struct uio *uio, int ioflag)
1396 {
1397 	int unit = MIDIUNIT(dev);
1398 	struct midi_softc *sc = midi_cd.cd_devs[unit];
1399 	struct midi_buffer *mb = &sc->outbuf;
1400 	int error;
1401 	u_char inp[256];
1402 	int s;
1403 	MIDI_BUF_DECLARE(idx);
1404 	MIDI_BUF_DECLARE(buf);
1405 	size_t idxspace;
1406 	size_t bufspace;
1407 	size_t xfrcount;
1408 	int pollout = 0;
1409 
1410 	DPRINTFN(6, ("midiwrite: %p, unit=%d, count=%lu\n", sc, unit,
1411 		     (unsigned long)uio->uio_resid));
1412 
1413 	if (sc->dying)
1414 		return EIO;
1415 
1416 	error = 0;
1417 	while (uio->uio_resid > 0 && !error) {
1418 
1419 		/*
1420 		 * block if necessary for the minimum buffer space to guarantee
1421 		 * we can write something.
1422 		 */
1423 		MIDI_OUT_LOCK(sc,s);
1424 		MIDI_BUF_PRODUCER_INIT(mb,idx); /* init can't go above loop; */
1425 		MIDI_BUF_PRODUCER_INIT(mb,buf); /* real_writebytes moves cur */
1426 		for ( ;; ) {
1427 			idxspace = MIDI_BUF_PRODUCER_REFRESH(mb,idx) - idx_cur;
1428 			bufspace = MIDI_BUF_PRODUCER_REFRESH(mb,buf) - buf_cur;
1429 			if ( idxspace >= 1  &&  bufspace >= 3  && !pollout )
1430 				break;
1431 			DPRINTFN(8,("midi_write: sleep idx=%d buf=%d\n",
1432 				 idxspace, bufspace));
1433 			if (ioflag & IO_NDELAY) {
1434 				error = EWOULDBLOCK;
1435 				/*
1436 				 * If some amount has already been transferred,
1437 				 * the common syscall code will automagically
1438 				 * convert this to success with a short count.
1439 				 */
1440 				goto locked_exit;
1441 			}
1442 			if ( pollout ) {
1443 				preempt(0); /* see midi_poll_output */
1444 				pollout = 0;
1445 			} else
1446 				error = midi_sleep(&sc->wchan, "mid wr",
1447 				                   &sc->out_lock);
1448 			if (error)
1449 				/*
1450 				 * Similarly, the common code will handle
1451 				 * EINTR and ERESTART properly here, changing to
1452 				 * a short count if something transferred.
1453 				 */
1454 				goto locked_exit;
1455 		}
1456 		MIDI_OUT_UNLOCK(sc,s);
1457 
1458 		/*
1459 		 * The number of bytes we can safely extract from the uio
1460 		 * depends on the available idx and buf space. Worst case,
1461 		 * every byte is a message so 1 idx is required per byte.
1462 		 * Worst case, the first byte completes a 3-byte msg in prior
1463 		 * state, and every subsequent byte is a Program Change or
1464 		 * Channel Pressure msg with running status and expands to 2
1465 		 * bytes, so the buf space reqd is 3+2(n-1) or 2n+1. So limit
1466 		 * the transfer to the min of idxspace and (bufspace-1)>>1.
1467 		 */
1468 		xfrcount = (bufspace - 1) >> 1;
1469 		if ( xfrcount > idxspace )
1470 			xfrcount = idxspace;
1471 		if ( xfrcount > sizeof inp )
1472 			xfrcount = sizeof inp;
1473 		if ( xfrcount > uio->uio_resid )
1474 			xfrcount = uio->uio_resid;
1475 
1476 		error = uiomove(inp, xfrcount, uio);
1477 #ifdef MIDI_DEBUG
1478 		if (error)
1479 		        printf("midi_write:(1) uiomove failed %d; "
1480 			       "xfrcount=%d inp=%p\n",
1481 			       error, xfrcount, inp);
1482 #endif
1483 		if ( error )
1484 			break;
1485 
1486 		/*
1487 		 * The number of bytes we extracted being calculated to
1488 		 * definitely fit in the buffer even with canonicalization,
1489 		 * there is no excuse for real_writebytes to return EWOULDBLOCK.
1490 		 */
1491 		error = real_writebytes(sc, inp, xfrcount);
1492 		KASSERT(error != EWOULDBLOCK);
1493 
1494 		if ( error )
1495 			break;
1496 		/*
1497 		 * If this is a polling device and we just sent a buffer, let's
1498 		 * not send another without giving some other process a chance.
1499 		 */
1500 		if ( ! (sc->props & MIDI_PROP_OUT_INTR) )
1501 			pollout = 1;
1502 		DPRINTFN(8,("midiwrite: uio_resid now %u, props=%d\n",
1503                         uio->uio_resid, sc->props));
1504 	}
1505 	return error;
1506 
1507 locked_exit:
1508 	MIDI_OUT_UNLOCK(sc,s);
1509 	return error;
1510 }
1511 
1512 /*
1513  * This write routine is only called from sequencer code and expects
1514  * a write that is smaller than the MIDI buffer.
1515  */
1516 int
1517 midi_writebytes(int unit, u_char *bf, int cc)
1518 {
1519 	struct midi_softc *sc = midi_cd.cd_devs[unit];
1520 
1521 	DPRINTFN(7, ("midi_writebytes: %p, unit=%d, cc=%d %#02x %#02x %#02x\n",
1522                     sc, unit, cc, bf[0], bf[1], bf[2]));
1523 	return real_writebytes(sc, bf, cc);
1524 }
1525 
1526 int
1527 midiioctl(dev_t dev, u_long cmd, caddr_t addr, int flag, struct lwp *l)
1528 {
1529 	int unit = MIDIUNIT(dev);
1530 	struct midi_softc *sc = midi_cd.cd_devs[unit];
1531 	const struct midi_hw_if *hw = sc->hw_if;
1532 	int error;
1533 	int s;
1534 	MIDI_BUF_DECLARE(buf);
1535 
1536 	DPRINTFN(5,("midiioctl: %p cmd=0x%08lx\n", sc, cmd));
1537 
1538 	if (sc->dying)
1539 		return EIO;
1540 
1541 	error = 0;
1542 	switch (cmd) {
1543 	case FIONBIO:
1544 		/* All handled in the upper FS layer. */
1545 		break;
1546 
1547 	case FIONREAD:
1548 		/*
1549 		 * This code relies on the current implementation of midi_in
1550 		 * always updating buf and idx together in a critical section,
1551 		 * so buf always ends at a message boundary. Document this
1552 		 * ioctl as always returning a value such that the last message
1553 		 * included is complete (SysEx the only exception), and then
1554 		 * make sure the implementation doesn't regress.  NB that
1555 		 * means if this ioctl returns n and the proc then issues a
1556 		 * read of n, n bytes will be read, but if the proc issues a
1557 		 * read of m < n, fewer than m bytes may be read to ensure the
1558 		 * read ends at a message boundary.
1559 		 */
1560 		MIDI_IN_LOCK(sc,s);
1561 		MIDI_BUF_CONSUMER_INIT(&sc->inbuf,buf);
1562 		MIDI_IN_UNLOCK(sc,s);
1563 		*(int *)addr = buf_lim - buf_cur;
1564 		break;
1565 
1566 	case FIOASYNC:
1567 		if (*(int *)addr) {
1568 			if (sc->async)
1569 				return EBUSY;
1570 			sc->async = l->l_proc;
1571 			DPRINTFN(5,("midi_ioctl: FIOASYNC %p\n", l->l_proc));
1572 		} else
1573 			sc->async = 0;
1574 		break;
1575 
1576 #if 0
1577 	case MIDI_PRETIME:
1578 		/* XXX OSS
1579 		 * This should set up a read timeout, but that's
1580 		 * why we have poll(), so there's nothing yet. */
1581 		error = EINVAL;
1582 		break;
1583 #endif
1584 
1585 #ifdef MIDI_SAVE
1586 	case MIDI_GETSAVE:
1587 		error = copyout(&midisave, *(void **)addr, sizeof midisave);
1588   		break;
1589 #endif
1590 
1591 	default:
1592 		if (hw->ioctl)
1593 			error = hw->ioctl(sc->hw_hdl, cmd, addr, flag, l);
1594 		else
1595 			error = EINVAL;
1596 		break;
1597 	}
1598 	return error;
1599 }
1600 
1601 int
1602 midipoll(dev_t dev, int events, struct lwp *l)
1603 {
1604 	int unit = MIDIUNIT(dev);
1605 	struct midi_softc *sc = midi_cd.cd_devs[unit];
1606 	int revents = 0;
1607 	int s;
1608 	MIDI_BUF_DECLARE(idx);
1609 	MIDI_BUF_DECLARE(buf);
1610 
1611 	DPRINTFN(6,("midipoll: %p events=0x%x\n", sc, events));
1612 
1613 	if (sc->dying)
1614 		return POLLHUP;
1615 
1616 	s = splaudio();
1617 
1618 	if ((sc->flags&FREAD) && (events & (POLLIN | POLLRDNORM))) {
1619 		simple_lock(&sc->in_lock);
1620 		MIDI_BUF_CONSUMER_INIT(&sc->inbuf,idx);
1621 		if (idx_cur < idx_lim)
1622 			revents |= events & (POLLIN | POLLRDNORM);
1623 		else
1624 			selrecord(l, &sc->rsel);
1625 		simple_unlock(&sc->in_lock);
1626 	}
1627 
1628 	if ((sc->flags&FWRITE) && (events & (POLLOUT | POLLWRNORM))) {
1629 		simple_lock(&sc->out_lock);
1630 		MIDI_BUF_PRODUCER_INIT(&sc->outbuf,idx);
1631 		MIDI_BUF_PRODUCER_INIT(&sc->outbuf,buf);
1632 		if ( idx_lim - idx_cur >= 1  &&  buf_lim - buf_cur >= 3 )
1633 			revents |= events & (POLLOUT | POLLWRNORM);
1634 		else
1635 			selrecord(l, &sc->wsel);
1636 		simple_unlock(&sc->out_lock);
1637 	}
1638 
1639 	splx(s);
1640 	return revents;
1641 }
1642 
1643 static void
1644 filt_midirdetach(struct knote *kn)
1645 {
1646 	struct midi_softc *sc = kn->kn_hook;
1647 	int s;
1648 
1649 	s = splaudio();
1650 	SLIST_REMOVE(&sc->rsel.sel_klist, kn, knote, kn_selnext);
1651 	splx(s);
1652 }
1653 
1654 static int
1655 filt_midiread(struct knote *kn, long hint __unused)
1656 {
1657 	struct midi_softc *sc = kn->kn_hook;
1658 	int s;
1659 	MIDI_BUF_DECLARE(buf);
1660 
1661 	/* XXXLUKEM (thorpej): please make sure this is correct. */
1662 
1663 	MIDI_IN_LOCK(sc,s);
1664 	MIDI_BUF_CONSUMER_INIT(&sc->inbuf,buf);
1665 	kn->kn_data = buf_lim - buf_cur;
1666 	MIDI_IN_UNLOCK(sc,s);
1667 	return (kn->kn_data > 0);
1668 }
1669 
1670 static const struct filterops midiread_filtops =
1671 	{ 1, NULL, filt_midirdetach, filt_midiread };
1672 
1673 static void
1674 filt_midiwdetach(struct knote *kn)
1675 {
1676 	struct midi_softc *sc = kn->kn_hook;
1677 	int s;
1678 
1679 	s = splaudio();
1680 	SLIST_REMOVE(&sc->wsel.sel_klist, kn, knote, kn_selnext);
1681 	splx(s);
1682 }
1683 
1684 static int
1685 filt_midiwrite(struct knote *kn, long hint __unused)
1686 {
1687 	struct midi_softc *sc = kn->kn_hook;
1688 	int s;
1689 	MIDI_BUF_DECLARE(idx);
1690 	MIDI_BUF_DECLARE(buf);
1691 
1692 	/* XXXLUKEM (thorpej): please make sure this is correct. */
1693 
1694 	MIDI_OUT_LOCK(sc,s);
1695 	MIDI_BUF_PRODUCER_INIT(&sc->outbuf,idx);
1696 	MIDI_BUF_PRODUCER_INIT(&sc->outbuf,buf);
1697 	kn->kn_data = ((buf_lim - buf_cur)-1)>>1;
1698 	if ( kn->kn_data > idx_lim - idx_cur )
1699 		kn->kn_data = idx_lim - idx_cur;
1700 	MIDI_OUT_UNLOCK(sc,s);
1701 	return (kn->kn_data > 0);
1702 }
1703 
1704 static const struct filterops midiwrite_filtops =
1705 	{ 1, NULL, filt_midiwdetach, filt_midiwrite };
1706 
1707 int
1708 midikqfilter(dev_t dev, struct knote *kn)
1709 {
1710 	int unit = MIDIUNIT(dev);
1711 	struct midi_softc *sc = midi_cd.cd_devs[unit];
1712 	struct klist *klist;
1713 	int s;
1714 
1715 	switch (kn->kn_filter) {
1716 	case EVFILT_READ:
1717 		klist = &sc->rsel.sel_klist;
1718 		kn->kn_fop = &midiread_filtops;
1719 		break;
1720 
1721 	case EVFILT_WRITE:
1722 		klist = &sc->wsel.sel_klist;
1723 		kn->kn_fop = &midiwrite_filtops;
1724 		break;
1725 
1726 	default:
1727 		return (1);
1728 	}
1729 
1730 	kn->kn_hook = sc;
1731 
1732 	s = splaudio();
1733 	SLIST_INSERT_HEAD(klist, kn, kn_selnext);
1734 	splx(s);
1735 
1736 	return (0);
1737 }
1738 
1739 void
1740 midi_getinfo(dev_t dev, struct midi_info *mi)
1741 {
1742 	struct midi_softc *sc;
1743 
1744 	sc = device_lookup(&midi_cd, MIDIUNIT(dev));
1745 	if (sc == NULL)
1746 		return;
1747 	if (sc->dying)
1748 		return;
1749 
1750 	sc->hw_if->getinfo(sc->hw_hdl, mi);
1751 }
1752 
1753 #elif NMIDIBUS > 0 /* but NMIDI == 0 */
1754 
1755 void midi_register_hw_if_ext(struct midi_hw_if_ext *exthw __unused) { /* stub */
1756 }
1757 
1758 #endif /* NMIDI > 0 */
1759 
1760 #if NMIDI > 0 || NMIDIBUS > 0
1761 
1762 int	audioprint(void *, const char *);
1763 
1764 struct device *
1765 midi_attach_mi(const struct midi_hw_if *mhwp, void *hdlp, struct device *dev)
1766 {
1767 	struct audio_attach_args arg;
1768 
1769 #ifdef DIAGNOSTIC
1770 	if (mhwp == NULL) {
1771 		aprint_error("midi_attach_mi: NULL\n");
1772 		return (0);
1773 	}
1774 #endif
1775 	arg.type = AUDIODEV_TYPE_MIDI;
1776 	arg.hwif = mhwp;
1777 	arg.hdl = hdlp;
1778 	return (config_found(dev, &arg, audioprint));
1779 }
1780 
1781 #endif /* NMIDI > 0 || NMIDIBUS > 0 */
1782