xref: /netbsd-src/sys/dev/midi.c (revision 6deb2c22d20de1d75d538e8a5c57b573926fd157)
1 /*	$NetBSD: midi.c,v 1.70 2009/08/23 15:56:07 jmcneill 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  *
20  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
21  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
22  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
23  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
24  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
25  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
26  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
27  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
28  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
29  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
30  * POSSIBILITY OF SUCH DAMAGE.
31  */
32 
33 #include <sys/cdefs.h>
34 __KERNEL_RCSID(0, "$NetBSD: midi.c,v 1.70 2009/08/23 15:56:07 jmcneill Exp $");
35 
36 #include "midi.h"
37 #include "sequencer.h"
38 
39 #include <sys/param.h>
40 #include <sys/ioctl.h>
41 #include <sys/fcntl.h>
42 #include <sys/vnode.h>
43 #include <sys/select.h>
44 #include <sys/poll.h>
45 #include <sys/malloc.h>
46 #include <sys/proc.h>
47 #include <sys/systm.h>
48 #include <sys/callout.h>
49 #include <sys/syslog.h>
50 #include <sys/kernel.h>
51 #include <sys/signalvar.h>
52 #include <sys/conf.h>
53 #include <sys/audioio.h>
54 #include <sys/midiio.h>
55 #include <sys/device.h>
56 #include <sys/intr.h>
57 
58 #include <dev/audio_if.h>
59 #include <dev/midi_if.h>
60 #include <dev/midivar.h>
61 
62 #if NMIDI > 0
63 
64 #ifdef AUDIO_DEBUG
65 #define DPRINTF(x)	if (mididebug) printf x
66 #define DPRINTFN(n,x)	if (mididebug >= (n)) printf x
67 int	mididebug = 0;
68 /*
69  *      1: detected protocol errors and buffer overflows
70  *      2: probe, attach, detach
71  *      3: open, close
72  *      4: data received except realtime
73  *      5: ioctl
74  *      6: read, write, poll
75  *      7: data transmitted
76  *      8: uiomoves, synchronization
77  *      9: realtime data received
78  */
79 #else
80 #define DPRINTF(x)
81 #define DPRINTFN(n,x)
82 #endif
83 
84 static	struct simplelock hwif_register_lock = SIMPLELOCK_INITIALIZER;
85 static	struct midi_softc *hwif_softc = NULL;
86 
87 void	midi_in(void *, int);
88 void	midi_out(void *);
89 int     midi_poll_out(struct midi_softc *);
90 int     midi_intr_out(struct midi_softc *);
91 int 	midi_msg_out(struct midi_softc *,
92                  u_char **, u_char **, u_char **, u_char **);
93 int	midi_start_output(struct midi_softc *);
94 int	midi_sleep_timo(int *, const char *, int, struct simplelock *);
95 int	midi_sleep(int *, const char *, struct simplelock *);
96 void	midi_wakeup(int *);
97 void	midi_initbuf(struct midi_buffer *);
98 void	midi_xmt_asense(void *);
99 void	midi_rcv_asense(void *);
100 void	midi_softintr_rd(void *);
101 void	midi_softintr_wr(void *);
102 
103 int	midiprobe(device_t, cfdata_t, void *);
104 void	midiattach(device_t, device_t, void *);
105 int	mididetach(device_t, int);
106 int	midiactivate(device_t, enum devact);
107 
108 dev_type_open(midiopen);
109 dev_type_close(midiclose);
110 dev_type_read(midiread);
111 dev_type_write(midiwrite);
112 dev_type_ioctl(midiioctl);
113 dev_type_poll(midipoll);
114 dev_type_kqfilter(midikqfilter);
115 
116 const struct cdevsw midi_cdevsw = {
117 	midiopen, midiclose, midiread, midiwrite, midiioctl,
118 	nostop, notty, midipoll, nommap, midikqfilter, D_OTHER,
119 };
120 
121 CFATTACH_DECL_NEW(midi, sizeof(struct midi_softc),
122     midiprobe, midiattach, mididetach, midiactivate);
123 
124 #define MIDI_XMT_ASENSE_PERIOD mstohz(275)
125 #define MIDI_RCV_ASENSE_PERIOD mstohz(300)
126 
127 extern struct cfdriver midi_cd;
128 
129 int
130 midiprobe(device_t parent, cfdata_t match, void *aux)
131 {
132 	struct audio_attach_args *sa = aux;
133 
134 	DPRINTFN(2,("midiprobe: type=%d sa=%p hw=%p\n",
135 		 sa->type, sa, sa->hwif));
136 	return (sa->type == AUDIODEV_TYPE_MIDI);
137 }
138 
139 void
140 midiattach(device_t parent, device_t self, void *aux)
141 {
142 	struct midi_softc *sc = device_private(self);
143 	struct audio_attach_args *sa = aux;
144 	const struct midi_hw_if *hwp = sa->hwif;
145 	void *hdlp = sa->hdl;
146 
147 	aprint_naive("\n");
148 
149 	DPRINTFN(2, ("MIDI attach\n"));
150 
151 #ifdef DIAGNOSTIC
152 	if (hwp == 0 ||
153 	    hwp->open == 0 ||
154 	    hwp->close == 0 ||
155 	    hwp->output == 0 ||
156 	    hwp->getinfo == 0) {
157 		printf("midi: missing method\n");
158 		return;
159 	}
160 #endif
161 
162 	sc->dev = self;
163 	sc->hw_if = hwp;
164 	sc->hw_hdl = hdlp;
165 	midi_attach(sc, parent);
166         if (!device_pmf_is_registered(self))
167 		if (!pmf_device_register(self, NULL, NULL))
168 			aprint_error_dev(self,
169 			    "couldn't establish power handler\n");
170 }
171 
172 int
173 midiactivate(device_t self, enum devact act)
174 {
175 	struct midi_softc *sc = device_private(self);
176 
177 	switch (act) {
178 	case DVACT_ACTIVATE:
179 		return (EOPNOTSUPP);
180 
181 	case DVACT_DEACTIVATE:
182 		sc->dying = 1;
183 		break;
184 	}
185 	return (0);
186 }
187 
188 int
189 mididetach(device_t self, int flags)
190 {
191 	struct midi_softc *sc = device_private(self);
192 	int maj, mn;
193 
194 	DPRINTFN(2,("%s: sc=%p flags=%d\n", __func__, sc, flags));
195 
196 	pmf_device_deregister(self);
197 
198 	sc->dying = 1;
199 
200 	wakeup(&sc->wchan);
201 	wakeup(&sc->rchan);
202 
203 	/* locate the major number */
204 	maj = cdevsw_lookup_major(&midi_cdevsw);
205 
206 	/* Nuke the vnodes for any open instances (calls close). */
207 	mn = device_unit(self);
208 	vdevgone(maj, mn, mn, VCHR);
209 
210 	if ( !(sc->props & MIDI_PROP_NO_OUTPUT) ) {
211 		evcnt_detach(&sc->xmt.bytesDiscarded);
212 		evcnt_detach(&sc->xmt.incompleteMessages);
213 	}
214 	if ( sc->props & MIDI_PROP_CAN_INPUT ) {
215 		evcnt_detach(&sc->rcv.bytesDiscarded);
216 		evcnt_detach(&sc->rcv.incompleteMessages);
217 	}
218 
219 	if (sc->sih_rd != NULL) {
220 		softint_disestablish(sc->sih_rd);
221 		sc->sih_rd = NULL;
222 	}
223 	if (sc->sih_wr != NULL) {
224 		softint_disestablish(sc->sih_wr);
225 		sc->sih_wr = NULL;
226 	}
227 
228 	return (0);
229 }
230 
231 void
232 midi_attach(struct midi_softc *sc, device_t parent)
233 {
234 	struct midi_info mi;
235 	int s;
236 
237 	callout_init(&sc->xmt_asense_co, 0);
238 	callout_init(&sc->rcv_asense_co, 0);
239 	callout_setfunc(&sc->xmt_asense_co, midi_xmt_asense, sc);
240 	callout_setfunc(&sc->rcv_asense_co, midi_rcv_asense, sc);
241 	simple_lock_init(&sc->out_lock);
242 	simple_lock_init(&sc->in_lock);
243 	sc->dying = 0;
244 	sc->isopen = 0;
245 
246 	sc->sc_dev = parent;
247 
248 	sc->sih_rd = softint_establish(SOFTINT_SERIAL, midi_softintr_rd, sc);
249 	sc->sih_wr = softint_establish(SOFTINT_SERIAL, midi_softintr_wr, sc);
250 
251 	s = splaudio();
252 	simple_lock(&hwif_register_lock);
253 	hwif_softc = sc;
254 	sc->hw_if->getinfo(sc->hw_hdl, &mi);
255 	hwif_softc = NULL;
256 	simple_unlock(&hwif_register_lock);
257 	splx(s);
258 
259 	sc->props = mi.props;
260 
261 	if ( !(sc->props & MIDI_PROP_NO_OUTPUT) ) {
262 		evcnt_attach_dynamic(&sc->xmt.bytesDiscarded,
263 			EVCNT_TYPE_MISC, NULL,
264 			device_xname(sc->dev), "xmt bytes discarded");
265 		evcnt_attach_dynamic(&sc->xmt.incompleteMessages,
266 			EVCNT_TYPE_MISC, NULL,
267 			device_xname(sc->dev), "xmt incomplete msgs");
268 	}
269 	if ( sc->props & MIDI_PROP_CAN_INPUT ) {
270 		evcnt_attach_dynamic(&sc->rcv.bytesDiscarded,
271 			EVCNT_TYPE_MISC, NULL,
272 			device_xname(sc->dev), "rcv bytes discarded");
273 		evcnt_attach_dynamic(&sc->rcv.incompleteMessages,
274 			EVCNT_TYPE_MISC, NULL,
275 			device_xname(sc->dev), "rcv incomplete msgs");
276 	}
277 
278 	aprint_normal(": %s\n", mi.name);
279 }
280 
281 void midi_register_hw_if_ext(struct midi_hw_if_ext *exthw) {
282 	if ( hwif_softc != NULL ) /* ignore calls resulting from non-init */
283 		hwif_softc->hw_if_ext = exthw; /* uses of getinfo */
284 }
285 
286 int
287 midi_unit_count(void)
288 {
289 	int i;
290 	for ( i = 0; i < midi_cd.cd_ndevs; ++i )
291 	        if ( NULL == device_lookup(&midi_cd, i) )
292 		        break;
293         return i;
294 }
295 
296 void
297 midi_initbuf(struct midi_buffer *mb)
298 {
299 	mb->idx_producerp = mb->idx_consumerp = mb->idx;
300 	mb->buf_producerp = mb->buf_consumerp = mb->buf;
301 }
302 #define PACK_MB_IDX(cat,len) (((cat)<<4)|(len))
303 #define MB_IDX_CAT(idx) ((idx)>>4)
304 #define MB_IDX_LEN(idx) ((idx)&0xf)
305 
306 int
307 midi_sleep_timo(int *chan, const char *label, int timo, struct simplelock *lk)
308 {
309 	int st;
310 
311 	if (!label)
312 		label = "midi";
313 
314 	DPRINTFN(8, ("midi_sleep_timo: %p %s %d\n", chan, label, timo));
315 	*chan = 1;
316 	st = ltsleep(chan, PWAIT | PCATCH, label, timo, lk);
317 	*chan = 0;
318 #ifdef MIDI_DEBUG
319 	if (st != 0)
320 		printf("midi_sleep: %d\n", st);
321 #endif
322 	return st;
323 }
324 
325 int
326 midi_sleep(int *chan, const char *label, struct simplelock *lk)
327 {
328 	return midi_sleep_timo(chan, label, 0, lk);
329 }
330 
331 void
332 midi_wakeup(int *chan)
333 {
334 	if (*chan) {
335 		DPRINTFN(8, ("midi_wakeup: %p\n", chan));
336 		wakeup(chan);
337 		*chan = 0;
338 	}
339 }
340 
341 /* in midivar.h:
342 #define MIDI_CAT_DATA 0
343 #define MIDI_CAT_STATUS1 1
344 #define MIDI_CAT_STATUS2 2
345 #define MIDI_CAT_COMMON 3
346 */
347 static char const midi_cats[] = "\0\0\0\0\0\0\0\0\2\2\2\2\1\1\2\3";
348 #define MIDI_CAT(d) (midi_cats[((d)>>4)&15])
349 #define FST_RETURN(offp,endp,ret) \
350 	return (s->pos=s->msg+(offp)), (s->end=s->msg+(endp)), (ret)
351 
352 enum fst_ret { FST_CHN, FST_CHV, FST_COM, FST_SYX, FST_RT, FST_MORE, FST_ERR,
353                FST_HUH, FST_SXP };
354 enum fst_form { FST_CANON, FST_COMPR, FST_VCOMP };
355 static struct {
356 	int off;
357 	enum fst_ret tag;
358 } const midi_forms[] = {
359 	[FST_CANON] = { .off=0, .tag=FST_CHN },
360 	[FST_COMPR] = { .off=1, .tag=FST_CHN },
361 	[FST_VCOMP] = { .off=0, .tag=FST_CHV }
362 };
363 #define FST_CRETURN(endp) \
364 	FST_RETURN(midi_forms[form].off,endp,midi_forms[form].tag)
365 
366 /*
367  * A MIDI finite state transducer suitable for receiving or transmitting. It
368  * will accept correct MIDI input that uses, doesn't use, or sometimes uses the
369  * 'running status' compression technique, and transduce it to fully expanded
370  * (form=FST_CANON) or fully compressed (form=FST_COMPR or FST_VCOMP) form.
371  *
372  * Returns FST_MORE if a complete message has not been parsed yet (SysEx
373  * messages are the exception), FST_ERR or FST_HUH if the input does not
374  * conform to the protocol, or FST_CHN (channel messages), FST_COM (System
375  * Common messages), FST_RT (System Real-Time messages), or FST_SYX (System
376  * Exclusive) to broadly categorize the message parsed. s->pos and s->end
377  * locate the parsed message; while (s->pos<s->end) putchar(*(s->pos++));
378  * would output it.
379  *
380  * FST_HUH means the character c wasn't valid in the original state, but the
381  * state has now been reset to START and the caller should try again passing
382  * the same c. FST_ERR means c isn't valid in the start state; the caller
383  * should kiss it goodbye and continue to try successive characters from the
384  * input until something other than FST_ERR or FST_HUH is returned, at which
385  * point things are resynchronized.
386  *
387  * A FST_SYX return means that between pos and end are from 1 to 3
388  * bytes of a system exclusive message. A SysEx message will be delivered in
389  * one or more chunks of that form, where the first begins with 0xf0 and the
390  * last (which is the only one that might have length < 3) ends with 0xf7.
391  *
392  * Messages corrupted by a protocol error are discarded and won't be seen at
393  * all; again SysEx is the exception, as one or more chunks of it may already
394  * have been parsed.
395  *
396  * For FST_CHN messages, s->msg[0] always contains the status byte even if
397  * FST_COMPR form was requested (pos then points to msg[1]). That way, the
398  * caller can always identify the exact message if there is a need to do so.
399  * For all other message types except FST_SYX, the status byte is at *pos
400  * (which may not necessarily be msg[0]!). There is only one SysEx status
401  * byte, so the return value FST_SYX is sufficient to identify it.
402  *
403  * To simplify some use cases, compression can also be requested with
404  * form=FST_VCOMP. In this form a compressible channel message is indicated
405  * by returning a classification of FST_CHV instead of FST_CHN, and pos points
406  * to the status byte rather than being advanced past it. If the caller in this
407  * case saves the bytes from pos to end, it will have saved the entire message,
408  * and can act on the FST_CHV tag to drop the first byte later. In this form,
409  * unlike FST_CANON, hidden note-off (i.e. note-on with velocity 0) may occur.
410  *
411  * Two obscure points in the MIDI protocol complicate things further, both to
412  * do with the EndSysEx code, 0xf7. First, this code is permitted (and
413  * meaningless) outside of a System Exclusive message, anywhere a status byte
414  * could appear. Second, it is allowed to be absent at the end of a System
415  * Exclusive message (!) - any status byte at all (non-realtime) is allowed to
416  * terminate the message. Both require accomodation in the interface to
417  * midi_fst's caller. A stray 0xf7 should be ignored BUT should count as a
418  * message received for purposes of Active Sense timeout; the case is
419  * represented by a return of FST_COM with a length of zero (pos == end). A
420  * status byte other than 0xf7 during a system exclusive message will cause an
421  * FST_SXP (sysex plus) return; the bytes from pos to end are the end of the
422  * system exclusive message, and after handling those the caller should call
423  * midi_fst again with the same input byte.
424  *
425  * midi(4) will never produce either such form of rubbish.
426  */
427 static enum fst_ret
428 midi_fst(struct midi_state *s, u_char c, enum fst_form form)
429 {
430 	int syxpos = 0;
431 
432 	if ( c >= 0xf8 ) { /* All realtime messages bypass state machine */
433 	        if ( c == 0xf9  ||  c == 0xfd ) {
434 			DPRINTF( ("midi_fst: s=%p c=0x%02x undefined\n",
435 				  s, c));
436 			s->bytesDiscarded.ev_count++;
437 			return FST_ERR;
438 		}
439 		DPRINTFN(9, ("midi_fst: s=%p System Real-Time data=0x%02x\n",
440 			     s, c));
441 		s->msg[2] = c;
442 		FST_RETURN(2,3,FST_RT);
443 	}
444 
445 	DPRINTFN(4, ("midi_fst: s=%p data=0x%02x state=%d\n",
446 		     s, c, s->state));
447 
448         switch ( s->state   | MIDI_CAT(c) ) { /* break ==> return FST_MORE */
449 
450 	case MIDI_IN_START  | MIDI_CAT_COMMON:
451 	case MIDI_IN_RUN1_1 | MIDI_CAT_COMMON:
452 	case MIDI_IN_RUN2_2 | MIDI_CAT_COMMON:
453 	case MIDI_IN_RXX2_2 | MIDI_CAT_COMMON:
454 	        s->msg[0] = c;
455 	        switch ( c ) {
456 		case 0xf0: s->state = MIDI_IN_SYX1_3; break;
457 		case 0xf1: s->state = MIDI_IN_COM0_1; break;
458 		case 0xf2: s->state = MIDI_IN_COM0_2; break;
459 		case 0xf3: s->state = MIDI_IN_COM0_1; break;
460 		case 0xf6: s->state = MIDI_IN_START;  FST_RETURN(0,1,FST_COM);
461 		case 0xf7: s->state = MIDI_IN_START;  FST_RETURN(0,0,FST_COM);
462 		default: goto protocol_violation;
463 		}
464 		break;
465 
466 	case MIDI_IN_RUN1_1 | MIDI_CAT_STATUS1:
467 		if ( c == s->msg[0] ) {
468 			s->state = MIDI_IN_RNX0_1;
469 			break;
470 		}
471 		/* FALLTHROUGH */
472 	case MIDI_IN_RUN2_2 | MIDI_CAT_STATUS1:
473 	case MIDI_IN_RXX2_2 | MIDI_CAT_STATUS1:
474 	case MIDI_IN_START  | MIDI_CAT_STATUS1:
475 	        s->state = MIDI_IN_RUN0_1;
476 	        s->msg[0] = c;
477 		break;
478 
479 	case MIDI_IN_RUN2_2 | MIDI_CAT_STATUS2:
480 	case MIDI_IN_RXX2_2 | MIDI_CAT_STATUS2:
481 		if ( c == s->msg[0] ) {
482 			s->state = MIDI_IN_RNX0_2;
483 			break;
484 		}
485 		if ( (c ^ s->msg[0]) == 0x10 && (c & 0xe0) == 0x80 ) {
486 			s->state = MIDI_IN_RXX0_2;
487 			s->msg[0] = c;
488 			break;
489 		}
490 		/* FALLTHROUGH */
491 	case MIDI_IN_RUN1_1 | MIDI_CAT_STATUS2:
492 	case MIDI_IN_START  | MIDI_CAT_STATUS2:
493 	        s->state = MIDI_IN_RUN0_2;
494 	        s->msg[0] = c;
495 		break;
496 
497         case MIDI_IN_COM0_1 | MIDI_CAT_DATA:
498 		s->state = MIDI_IN_START;
499 	        s->msg[1] = c;
500 		FST_RETURN(0,2,FST_COM);
501 
502         case MIDI_IN_COM0_2 | MIDI_CAT_DATA:
503 	        s->state = MIDI_IN_COM1_2;
504 	        s->msg[1] = c;
505 		break;
506 
507         case MIDI_IN_COM1_2 | MIDI_CAT_DATA:
508 		s->state = MIDI_IN_START;
509 	        s->msg[2] = c;
510 		FST_RETURN(0,3,FST_COM);
511 
512         case MIDI_IN_RUN0_1 | MIDI_CAT_DATA:
513 		s->state = MIDI_IN_RUN1_1;
514 	        s->msg[1] = c;
515 		FST_RETURN(0,2,FST_CHN);
516 
517         case MIDI_IN_RUN1_1 | MIDI_CAT_DATA:
518         case MIDI_IN_RNX0_1 | MIDI_CAT_DATA:
519 		s->state = MIDI_IN_RUN1_1;
520 	        s->msg[1] = c;
521 		FST_CRETURN(2);
522 
523         case MIDI_IN_RUN0_2 | MIDI_CAT_DATA:
524 	        s->state = MIDI_IN_RUN1_2;
525 	        s->msg[1] = c;
526 		break;
527 
528         case MIDI_IN_RUN1_2 | MIDI_CAT_DATA:
529 		if ( FST_CANON == form && 0 == c && (s->msg[0]&0xf0) == 0x90 ) {
530 			s->state = MIDI_IN_RXX2_2;
531 			s->msg[0] ^= 0x10;
532 			s->msg[2] = 64;
533 		} else {
534 			s->state = MIDI_IN_RUN2_2;
535 	        	s->msg[2] = c;
536 		}
537 		FST_RETURN(0,3,FST_CHN);
538 
539         case MIDI_IN_RUN2_2 | MIDI_CAT_DATA:
540 	        s->state = MIDI_IN_RNX1_2;
541 	        s->msg[1] = c;
542 		break;
543 
544         case MIDI_IN_RXX2_2 | MIDI_CAT_DATA:
545 	        s->state = MIDI_IN_RXX1_2;
546 		s->msg[0] ^= 0x10;
547 	        s->msg[1] = c;
548 		break;
549 
550         case MIDI_IN_RNX0_2 | MIDI_CAT_DATA:
551 	        s->state = MIDI_IN_RNY1_2;
552 	        s->msg[1] = c;
553 		break;
554 
555         case MIDI_IN_RXX0_2 | MIDI_CAT_DATA:
556 	        s->state = MIDI_IN_RXY1_2;
557 	        s->msg[1] = c;
558 		break;
559 
560         case MIDI_IN_RNX1_2 | MIDI_CAT_DATA:
561         case MIDI_IN_RNY1_2 | MIDI_CAT_DATA:
562 		if ( FST_CANON == form && 0 == c && (s->msg[0]&0xf0) == 0x90 ) {
563 			s->state = MIDI_IN_RXX2_2;
564 			s->msg[0] ^= 0x10;
565 			s->msg[2] = 64;
566 			FST_RETURN(0,3,FST_CHN);
567 		}
568 		s->state = MIDI_IN_RUN2_2;
569 	        s->msg[2] = c;
570 		FST_CRETURN(3);
571 
572         case MIDI_IN_RXX1_2 | MIDI_CAT_DATA:
573         case MIDI_IN_RXY1_2 | MIDI_CAT_DATA:
574 		if ( ( 0 == c && (s->msg[0]&0xf0) == 0x90)
575 		  || (64 == c && (s->msg[0]&0xf0) == 0x80
576 		      && FST_CANON != form) ) {
577 			s->state = MIDI_IN_RXX2_2;
578 			s->msg[0] ^= 0x10;
579 			s->msg[2] = 64 - c;
580 			FST_CRETURN(3);
581 		}
582 		s->state = MIDI_IN_RUN2_2;
583 	        s->msg[2] = c;
584 		FST_RETURN(0,3,FST_CHN);
585 
586         case MIDI_IN_SYX1_3 | MIDI_CAT_DATA:
587 		s->state = MIDI_IN_SYX2_3;
588 	        s->msg[1] = c;
589 		break;
590 
591         case MIDI_IN_SYX2_3 | MIDI_CAT_DATA:
592 		s->state = MIDI_IN_SYX0_3;
593 	        s->msg[2] = c;
594 		FST_RETURN(0,3,FST_SYX);
595 
596         case MIDI_IN_SYX0_3 | MIDI_CAT_DATA:
597 		s->state = MIDI_IN_SYX1_3;
598 	        s->msg[0] = c;
599 		break;
600 
601         case MIDI_IN_SYX2_3 | MIDI_CAT_COMMON:
602         case MIDI_IN_SYX2_3 | MIDI_CAT_STATUS1:
603         case MIDI_IN_SYX2_3 | MIDI_CAT_STATUS2:
604 		++ syxpos;
605 		/* FALLTHROUGH */
606         case MIDI_IN_SYX1_3 | MIDI_CAT_COMMON:
607         case MIDI_IN_SYX1_3 | MIDI_CAT_STATUS1:
608         case MIDI_IN_SYX1_3 | MIDI_CAT_STATUS2:
609 		++ syxpos;
610 		/* FALLTHROUGH */
611         case MIDI_IN_SYX0_3 | MIDI_CAT_COMMON:
612         case MIDI_IN_SYX0_3 | MIDI_CAT_STATUS1:
613         case MIDI_IN_SYX0_3 | MIDI_CAT_STATUS2:
614 		s->state = MIDI_IN_START;
615 	        if ( c == 0xf7 ) {
616 			s->msg[syxpos] = c;
617 		        FST_RETURN(0,1+syxpos,FST_SYX);
618 		}
619 		s->msg[syxpos] = 0xf7;
620 		FST_RETURN(0,1+syxpos,FST_SXP);
621 
622         default:
623 protocol_violation:
624                 DPRINTF(("midi_fst: unexpected %#02x in state %u\n",
625 		        c, s->state));
626 		switch ( s->state ) {
627 		case MIDI_IN_RUN1_1: /* can only get here by seeing an */
628 		case MIDI_IN_RUN2_2: /* INVALID System Common message */
629 		case MIDI_IN_RXX2_2:
630 		        s->state = MIDI_IN_START;
631 			/* FALLTHROUGH */
632 		case MIDI_IN_START:
633 			s->bytesDiscarded.ev_count++;
634 			return FST_ERR;
635 		case MIDI_IN_COM1_2:
636 		case MIDI_IN_RUN1_2:
637 		case MIDI_IN_RNY1_2:
638 		case MIDI_IN_RXY1_2:
639 			s->bytesDiscarded.ev_count++;
640 			/* FALLTHROUGH */
641 		case MIDI_IN_COM0_1:
642 		case MIDI_IN_RUN0_1:
643 		case MIDI_IN_RNX0_1:
644 		case MIDI_IN_COM0_2:
645 		case MIDI_IN_RUN0_2:
646 		case MIDI_IN_RNX0_2:
647 		case MIDI_IN_RXX0_2:
648 		case MIDI_IN_RNX1_2:
649 		case MIDI_IN_RXX1_2:
650 			s->bytesDiscarded.ev_count++;
651 		        s->incompleteMessages.ev_count++;
652 			break;
653 #if defined(AUDIO_DEBUG) || defined(DIAGNOSTIC)
654 		default:
655 		        printf("midi_fst: mishandled %#02x(%u) in state %u?!\n",
656 			      c, MIDI_CAT(c), s->state);
657 #endif
658 		}
659 		s->state = MIDI_IN_START;
660 		return FST_HUH;
661 	}
662 	return FST_MORE;
663 }
664 
665 void
666 midi_softintr_rd(void *cookie)
667 {
668 	struct midi_softc *sc = cookie;
669 	struct proc *p;
670 
671 	if (sc->async != NULL) {
672 		mutex_enter(proc_lock);
673 		if ((p = sc->async) != NULL)
674 			psignal(p, SIGIO);
675 		mutex_exit(proc_lock);
676 	}
677 	midi_wakeup(&sc->rchan);
678 	selnotify(&sc->rsel, 0, 0); /* filter will spin if locked */
679 }
680 
681 void
682 midi_softintr_wr(void *cookie)
683 {
684 	struct midi_softc *sc = cookie;
685 	struct proc *p;
686 
687 	if (sc->async != NULL) {
688 		mutex_enter(proc_lock);
689 		if ((p = sc->async) != NULL)
690 			psignal(p, SIGIO);
691 		mutex_exit(proc_lock);
692 	}
693 	midi_wakeup(&sc->wchan);
694 	selnotify(&sc->wsel, 0, 0); /* filter will spin if locked */
695 }
696 
697 void
698 midi_in(void *addr, int data)
699 {
700 	struct midi_softc *sc = addr;
701 	struct midi_buffer *mb = &sc->inbuf;
702 	int i;
703 	int count;
704 	enum fst_ret got;
705 	int s; /* hw may have various spls so impose our own */
706 	MIDI_BUF_DECLARE(idx);
707 	MIDI_BUF_DECLARE(buf);
708 
709 	if (!sc->isopen)
710 		return;
711 
712 	if (!(sc->flags & FREAD))
713 		return;		/* discard data if not reading */
714 
715 sxp_again:
716 	do
717 		got = midi_fst(&sc->rcv, data, FST_CANON);
718 	while ( got == FST_HUH );
719 
720 	switch ( got ) {
721 	case FST_MORE:
722 	case FST_ERR:
723 		return;
724 	case FST_CHN:
725 	case FST_COM:
726 	case FST_RT:
727 #if NSEQUENCER > 0
728 		if (sc->seqopen) {
729 			extern void midiseq_in(struct midi_dev *,u_char *,int);
730 			count = sc->rcv.end - sc->rcv.pos;
731 			midiseq_in(sc->seq_md, sc->rcv.pos, count);
732 			return;
733 		}
734 #endif
735         	/*
736 		 * Pass Active Sense to the sequencer if it's open, but not to
737 		 * a raw reader. (Really should do something intelligent with
738 		 * it then, though....)
739 		 */
740 		if ( got == FST_RT && MIDI_ACK == sc->rcv.pos[0] ) {
741 			if ( !sc->rcv_expect_asense ) {
742 				sc->rcv_expect_asense = 1;
743 				callout_schedule(&sc->rcv_asense_co,
744 				                 MIDI_RCV_ASENSE_PERIOD);
745 			}
746 			sc->rcv_quiescent = 0;
747 			sc->rcv_eof = 0;
748 			return;
749 		}
750 		/* FALLTHROUGH */
751 	/*
752 	 * Ultimately SysEx msgs should be offered to the sequencer also; the
753 	 * sequencer API addresses them - but maybe our sequencer can't handle
754 	 * them yet, so offer only to raw reader. (Which means, ultimately,
755 	 * discard them if the sequencer's open, as it's not doing reads!)
756 	 * -> When SysEx support is added to the sequencer, be sure to handle
757 	 *    FST_SXP there too.
758 	 */
759 	case FST_SYX:
760 	case FST_SXP:
761 		count = sc->rcv.end - sc->rcv.pos;
762 		MIDI_IN_LOCK(sc,s);
763 		sc->rcv_quiescent = 0;
764 		sc->rcv_eof = 0;
765 		if ( 0 == count ) {
766 			MIDI_IN_UNLOCK(sc,s);
767 			break;
768 		}
769 		MIDI_BUF_PRODUCER_INIT(mb,idx);
770 		MIDI_BUF_PRODUCER_INIT(mb,buf);
771 		if (count > buf_lim - buf_cur
772 		     || 1 > idx_lim - idx_cur) {
773 			sc->rcv.bytesDiscarded.ev_count += count;
774 			MIDI_IN_UNLOCK(sc,s);
775 			DPRINTF(("midi_in: buffer full, discard data=0x%02x\n",
776 				 sc->rcv.pos[0]));
777 			return;
778 		}
779 		for (i = 0; i < count; i++) {
780 			*buf_cur++ = sc->rcv.pos[i];
781 			MIDI_BUF_WRAP(buf);
782 		}
783 		*idx_cur++ = PACK_MB_IDX(got,count);
784 		MIDI_BUF_WRAP(idx);
785 		MIDI_BUF_PRODUCER_WBACK(mb,buf);
786 		MIDI_BUF_PRODUCER_WBACK(mb,idx);
787 		MIDI_IN_UNLOCK(sc,s);
788 		softint_schedule(sc->sih_rd);
789 		break;
790 	default: /* don't #ifdef this away, gcc will say FST_HUH not handled */
791 		printf("midi_in: midi_fst returned %d?!\n", got);
792 	}
793 	if ( FST_SXP == got )
794 		goto sxp_again;
795 }
796 
797 void
798 midi_out(void *addr)
799 {
800 	struct midi_softc *sc = addr;
801 
802 	if (!sc->isopen)
803 		return;
804 	DPRINTFN(8, ("midi_out: %p\n", sc));
805 	midi_intr_out(sc);
806 }
807 
808 int
809 midiopen(dev_t dev, int flags, int ifmt, struct lwp *l)
810 {
811 	struct midi_softc *sc;
812 	const struct midi_hw_if *hw;
813 	int error;
814 
815 	sc = device_lookup_private(&midi_cd, MIDIUNIT(dev));
816 	if (sc == NULL)
817 		return (ENXIO);
818 	if (sc->dying)
819 		return (EIO);
820 
821 	DPRINTFN(3,("midiopen %p\n", sc));
822 
823 	hw = sc->hw_if;
824 	if (!hw)
825 		return ENXIO;
826 	if (sc->isopen)
827 		return EBUSY;
828 
829 	/* put both state machines into known states */
830 	sc->rcv.state = MIDI_IN_START;
831 	sc->rcv.pos = sc->rcv.msg;
832 	sc->rcv.end = sc->rcv.msg;
833 	sc->xmt.state = MIDI_IN_START;
834 	sc->xmt.pos = sc->xmt.msg;
835 	sc->xmt.end = sc->xmt.msg;
836 
837 	/* copy error counters so an ioctl (TBA) can give since-open stats */
838 	sc->rcv.atOpen.bytesDiscarded  = sc->rcv.bytesDiscarded.ev_count;
839 	sc->rcv.atQuery.bytesDiscarded = sc->rcv.bytesDiscarded.ev_count;
840 
841 	sc->xmt.atOpen.bytesDiscarded  = sc->xmt.bytesDiscarded.ev_count;
842 	sc->xmt.atQuery.bytesDiscarded = sc->xmt.bytesDiscarded.ev_count;
843 
844 	/* and the buffers */
845 	midi_initbuf(&sc->outbuf);
846 	midi_initbuf(&sc->inbuf);
847 
848 	/* and the receive flags */
849 	sc->rcv_expect_asense = 0;
850 	sc->rcv_quiescent = 0;
851 	sc->rcv_eof = 0;
852 
853 	error = hw->open(sc->hw_hdl, flags, midi_in, midi_out, sc);
854 	if (error)
855 		return error;
856 	sc->isopen++;
857 	sc->flags = flags;
858 	sc->rchan = 0;
859 	sc->wchan = 0;
860 	sc->pbus = 0;
861 	sc->async = 0;
862 
863 #ifdef MIDI_SAVE
864 	if (midicnt != 0) {
865 		midisave.cnt = midicnt;
866 		midicnt = 0;
867 	}
868 #endif
869 
870 	return 0;
871 }
872 
873 int
874 midiclose(dev_t dev, int flags, int ifmt,
875     struct lwp *l)
876 {
877 	struct midi_softc *sc =
878 	    device_lookup_private(&midi_cd, MIDIUNIT(dev));
879 	const struct midi_hw_if *hw = sc->hw_if;
880 	int s, error;
881 
882 	DPRINTFN(3,("midiclose %p\n", sc));
883 
884 	/* midi_start_output(sc); anything buffered => pbus already set! */
885 	error = 0;
886 	MIDI_OUT_LOCK(sc,s);
887 	while (sc->pbus) {
888 		DPRINTFN(8,("midiclose sleep ...\n"));
889 		error =
890 		midi_sleep_timo(&sc->wchan, "mid_dr", 30*hz, &sc->out_lock);
891 	}
892 	sc->isopen = 0;
893 	MIDI_OUT_UNLOCK(sc,s);
894 	callout_stop(&sc->xmt_asense_co); /* xxx fix this - sleep? */
895 	callout_stop(&sc->rcv_asense_co);
896 	hw->close(sc->hw_hdl);
897 #if NSEQUENCER > 0
898 	sc->seqopen = 0;
899 	sc->seq_md = 0;
900 #endif
901 	return 0;
902 }
903 
904 int
905 midiread(dev_t dev, struct uio *uio, int ioflag)
906 {
907 	struct midi_softc *sc =
908 	    device_lookup_private(&midi_cd, MIDIUNIT(dev));
909 	struct midi_buffer *mb = &sc->inbuf;
910 	int error;
911 	int s;
912 	MIDI_BUF_DECLARE(idx);
913 	MIDI_BUF_DECLARE(buf);
914 	int appetite;
915 	int first = 1;
916 
917 	DPRINTFN(6,("midiread: %p, count=%lu\n", sc,
918 		 (unsigned long)uio->uio_resid));
919 
920 	if (sc->dying)
921 		return EIO;
922         if ( !(sc->props & MIDI_PROP_CAN_INPUT) )
923 	        return ENXIO;
924 
925 	MIDI_IN_LOCK(sc,s);
926 	MIDI_BUF_CONSUMER_INIT(mb,idx);
927 	MIDI_BUF_CONSUMER_INIT(mb,buf);
928 	MIDI_IN_UNLOCK(sc,s);
929 
930 	error = 0;
931 	for ( ;; ) {
932 		/*
933 		 * If the used portion of idx wraps around the end, just take
934 		 * the first part on this iteration, and we'll get the rest on
935 		 * the next.
936 		 */
937 		if ( idx_lim > idx_end )
938 			idx_lim = idx_end;
939 		/*
940 		 * Count bytes through the last complete message that will
941 		 * fit in the requested read.
942 		 */
943 		for (appetite = uio->uio_resid; idx_cur < idx_lim; ++idx_cur) {
944 			if ( appetite < MB_IDX_LEN(*idx_cur) )
945 				break;
946 			appetite -= MB_IDX_LEN(*idx_cur);
947 		}
948 		appetite = uio->uio_resid - appetite;
949 		/*
950 		 * Only if the read is too small to hold even the first
951 		 * complete message will we return a partial one (updating idx
952 		 * to reflect the remaining length of the message).
953 		 */
954 		if ( appetite == 0 && idx_cur < idx_lim ) {
955 			if ( !first )
956 				goto unlocked_exit; /* idx_cur not advanced */
957 			appetite = uio->uio_resid;
958 			*idx_cur = PACK_MB_IDX(MB_IDX_CAT(*idx_cur),
959 					       MB_IDX_LEN(*idx_cur) - appetite);
960 		}
961 		KASSERT(buf_cur + appetite <= buf_lim);
962 
963 		/* move the bytes */
964 		if ( appetite > 0 ) {
965 			first = 0;  /* we know we won't return empty-handed */
966 			/* do two uiomoves if data wrap around end of buf */
967 			if ( buf_cur + appetite > buf_end ) {
968 				DPRINTFN(8,
969 					("midiread: uiomove cc=%td (prewrap)\n",
970 					buf_end - buf_cur));
971 				error = uiomove(buf_cur, buf_end-buf_cur, uio);
972 				if ( error )
973 					goto unlocked_exit;
974 				appetite -= buf_end - buf_cur;
975 				buf_cur = mb->buf;
976 			}
977 			DPRINTFN(8, ("midiread: uiomove cc=%d\n", appetite));
978 			error = uiomove(buf_cur, appetite, uio);
979 			if ( error )
980 				goto unlocked_exit;
981 			buf_cur += appetite;
982 		}
983 
984 		MIDI_BUF_WRAP(idx);
985 		MIDI_BUF_WRAP(buf);
986 
987 		MIDI_IN_LOCK(sc,s);
988 		MIDI_BUF_CONSUMER_WBACK(mb,idx);
989 		MIDI_BUF_CONSUMER_WBACK(mb,buf);
990 		if ( 0 == uio->uio_resid ) /* if read satisfied, we're done */
991 			break;
992 		MIDI_BUF_CONSUMER_REFRESH(mb,idx);
993 		if ( idx_cur == idx_lim ) { /* need to wait for data? */
994 			if ( !first || sc->rcv_eof ) /* never block reader if */
995 				break;            /* any data already in hand */
996 			if (ioflag & IO_NDELAY) {
997 				error = EWOULDBLOCK;
998 				break;
999 			}
1000 			error = midi_sleep(&sc->rchan, "mid rd", &sc->in_lock);
1001 			if ( error )
1002 				break;
1003 			MIDI_BUF_CONSUMER_REFRESH(mb,idx); /* what'd we get? */
1004 		}
1005 		MIDI_BUF_CONSUMER_REFRESH(mb,buf);
1006 		MIDI_IN_UNLOCK(sc,s);
1007 		if ( sc->dying )
1008 			return EIO;
1009 	}
1010 	MIDI_IN_UNLOCK(sc,s);
1011 
1012 unlocked_exit:
1013 	return error;
1014 }
1015 
1016 void
1017 midi_rcv_asense(void *arg)
1018 {
1019 	struct midi_softc *sc = arg;
1020 	int s;
1021 
1022 	if ( sc->dying || !sc->isopen )
1023 		return;
1024 
1025 	if ( sc->rcv_quiescent ) {
1026 		MIDI_IN_LOCK(sc,s);
1027 		sc->rcv_eof = 1;
1028 		sc->rcv_quiescent = 0;
1029 		sc->rcv_expect_asense = 0;
1030 		MIDI_IN_UNLOCK(sc,s);
1031 		softint_schedule(sc->sih_rd);
1032 		return;
1033 	}
1034 
1035 	sc->rcv_quiescent = 1;
1036 	callout_schedule(&sc->rcv_asense_co, MIDI_RCV_ASENSE_PERIOD);
1037 }
1038 
1039 void
1040 midi_xmt_asense(void *arg)
1041 {
1042 	struct midi_softc *sc = arg;
1043 	int s;
1044 	int error;
1045 	int armed;
1046 
1047 	if ( sc->dying || !sc->isopen )
1048 		return;
1049 
1050 	MIDI_OUT_LOCK(sc,s);
1051 	if ( sc->pbus || sc->dying || !sc->isopen ) {
1052 		MIDI_OUT_UNLOCK(sc,s);
1053 		return;
1054 	}
1055 	sc->pbus = 1;
1056 	DPRINTFN(8,("midi_xmt_asense: %p\n", sc));
1057 
1058 	if ( sc->props & MIDI_PROP_OUT_INTR ) {
1059 		error = sc->hw_if->output(sc->hw_hdl, MIDI_ACK);
1060 		armed = (error == 0);
1061 	} else { /* polled output, do with interrupts unmasked */
1062 		MIDI_OUT_UNLOCK(sc,s);
1063 		/* running from softclock, so top half won't sneak in here */
1064 		error = sc->hw_if->output(sc->hw_hdl, MIDI_ACK);
1065 		MIDI_OUT_LOCK(sc,s);
1066 		armed = 0;
1067 	}
1068 
1069 	if ( !armed ) {
1070 		sc->pbus = 0;
1071 		callout_schedule(&sc->xmt_asense_co, MIDI_XMT_ASENSE_PERIOD);
1072 	}
1073 
1074 	MIDI_OUT_UNLOCK(sc,s);
1075 }
1076 
1077 /*
1078  * The way this function was hacked up to plug into poll_out and intr_out
1079  * after they were written won't win it any beauty contests, but it'll work
1080  * (code in haste, refactor at leisure). This may be called with the lock
1081  * (by intr_out) or without the lock (by poll_out) so it only does what could
1082  * be safe either way.
1083  */
1084 int midi_msg_out(struct midi_softc *sc,
1085                  u_char **idx, u_char **idxl, u_char **buf, u_char **bufl) {
1086 	MIDI_BUF_DECLARE(idx);
1087 	MIDI_BUF_DECLARE(buf);
1088 	MIDI_BUF_EXTENT_INIT(&sc->outbuf,idx);
1089 	MIDI_BUF_EXTENT_INIT(&sc->outbuf,buf);
1090 	int length;
1091 	int error;
1092 	u_char contig[3];
1093 	u_char *cp;
1094 	u_char *ep;
1095 
1096 	idx_cur = *idx;
1097 	idx_lim = *idxl;
1098 	buf_cur = *buf;
1099 	buf_lim = *bufl;
1100 
1101 	length = MB_IDX_LEN(*idx_cur);
1102 
1103 	for ( cp = contig, ep = cp + length; cp < ep; ) {
1104 		*cp++ = *buf_cur++;
1105 		MIDI_BUF_WRAP(buf);
1106 	}
1107 	cp = contig;
1108 
1109 	switch ( MB_IDX_CAT(*idx_cur) ) {
1110 	case FST_CHV: /* chnmsg to be compressed (for device that wants it) */
1111 		++ cp;
1112 		-- length;
1113 		/* FALLTHROUGH */
1114 	case FST_CHN:
1115 		error = sc->hw_if_ext->channel(sc->hw_hdl,
1116 		                               MIDI_GET_STATUS(contig[0]),
1117 					       MIDI_GET_CHAN(contig[0]),
1118 					       cp, length);
1119 		break;
1120 	case FST_COM:
1121 		error = sc->hw_if_ext->common(sc->hw_hdl,
1122 		                              MIDI_GET_STATUS(contig[0]),
1123 					      cp, length);
1124 		break;
1125 	case FST_SYX:
1126 	case FST_SXP:
1127 		error = sc->hw_if_ext->sysex(sc->hw_hdl,
1128 					     cp, length);
1129 		break;
1130 	case FST_RT:
1131 		error = sc->hw_if->output(sc->hw_hdl, *cp);
1132 		break;
1133 	default:
1134 		error = EIO;
1135 	}
1136 
1137 	if ( !error ) {
1138 		++ idx_cur;
1139 		MIDI_BUF_WRAP(idx);
1140 		*idx  = idx_cur;
1141 		*idxl = idx_lim;
1142 		*buf  = buf_cur;
1143 		*bufl = buf_lim;
1144 	}
1145 
1146 	return error;
1147 }
1148 
1149 /*
1150  * midi_poll_out is intended for the midi hw (the vast majority of MIDI UARTs
1151  * on sound cards, apparently) that _do not have transmit-ready interrupts_.
1152  * Every call to hw_if->output for one of these may busy-wait to output the
1153  * byte; at the standard midi data rate that'll be 320us per byte. The
1154  * technique of writing only MIDI_MAX_WRITE bytes in a row and then waiting
1155  * for MIDI_WAIT does not reduce the total time spent busy-waiting, and it
1156  * adds arbitrary delays in transmission (and, since MIDI_WAIT is roughly the
1157  * same as the time to send MIDI_MAX_WRITE bytes, it effectively halves the
1158  * data rate). Here, a somewhat bolder approach is taken. Since midi traffic
1159  * is bursty but time-sensitive--most of the time there will be none at all,
1160  * but when there is it should go out ASAP--the strategy is to just get it
1161  * over with, and empty the buffer in one go. The effect this can have on
1162  * the rest of the system will be limited by the size of the buffer and the
1163  * sparseness of the traffic. But some precautions are in order. Interrupts
1164  * should all be unmasked when this is called, and midiwrite should not fill
1165  * the buffer more than once (when MIDI_PROP_CAN_INTR is false) without a
1166  * yield() so some other process can get scheduled. If the write is nonblocking,
1167  * midiwrite should return a short count rather than yield.
1168  *
1169  * Someday when there is fine-grained MP support, this should be reworked to
1170  * run in a callout so the writing process really could proceed concurrently.
1171  * But obviously where performance is a concern, interrupt-driven hardware
1172  * such as USB midi or (apparently) clcs will always be preferable. And it
1173  * seems (kern/32651) that many of the devices currently working in poll mode
1174  * may really have tx interrupt capability and want only implementation; that
1175  * ought to happen.
1176  */
1177 int
1178 midi_poll_out(struct midi_softc *sc)
1179 {
1180 	struct midi_buffer *mb = &sc->outbuf;
1181 	int error;
1182 	int msglen;
1183 	int s;
1184 	MIDI_BUF_DECLARE(idx);
1185 	MIDI_BUF_DECLARE(buf);
1186 
1187 	error = 0;
1188 
1189 	MIDI_OUT_LOCK(sc,s);
1190 	MIDI_BUF_CONSUMER_INIT(mb,idx);
1191 	MIDI_BUF_CONSUMER_INIT(mb,buf);
1192 	MIDI_OUT_UNLOCK(sc,s);
1193 
1194 	for ( ;; ) {
1195 		while ( idx_cur != idx_lim ) {
1196 			if ( sc->hw_if_ext ) {
1197 				error = midi_msg_out(sc, &idx_cur, &idx_lim,
1198 				                         &buf_cur, &buf_lim);
1199 				if ( error )
1200 					goto ioerror;
1201 				continue;
1202 			}
1203 			/* or, lacking hw_if_ext ... */
1204 			msglen = MB_IDX_LEN(*idx_cur);
1205 			DPRINTFN(7,("midi_poll_out: %p <- %#02x\n",
1206 				   sc->hw_hdl, *buf_cur));
1207 			error = sc->hw_if->output(sc->hw_hdl, *buf_cur);
1208 			if ( error )
1209 				goto ioerror;
1210 			++ buf_cur;
1211 			MIDI_BUF_WRAP(buf);
1212 			-- msglen;
1213 			if ( msglen )
1214 				*idx_cur = PACK_MB_IDX(MB_IDX_CAT(*idx_cur),
1215 				                       msglen);
1216 			else {
1217 				++ idx_cur;
1218 				MIDI_BUF_WRAP(idx);
1219 			}
1220 		}
1221 		KASSERT(buf_cur == buf_lim);
1222 		MIDI_OUT_LOCK(sc,s);
1223 		MIDI_BUF_CONSUMER_WBACK(mb,idx);
1224 		MIDI_BUF_CONSUMER_WBACK(mb,buf);
1225 		MIDI_BUF_CONSUMER_REFRESH(mb,idx); /* any more to transmit? */
1226 		MIDI_BUF_CONSUMER_REFRESH(mb,buf);
1227 		if ( idx_lim == idx_cur )
1228 			break; /* still holding lock */
1229 		MIDI_OUT_UNLOCK(sc,s);
1230 	}
1231 	goto disarm; /* lock held */
1232 
1233 ioerror:
1234 #if defined(AUDIO_DEBUG) || defined(DIAGNOSTIC)
1235 	aprint_error_dev(sc->dev, "midi_poll_output error %d\n", error);
1236 #endif
1237 	MIDI_OUT_LOCK(sc,s);
1238 	MIDI_BUF_CONSUMER_WBACK(mb,idx);
1239 	MIDI_BUF_CONSUMER_WBACK(mb,buf);
1240 
1241 disarm:
1242 	sc->pbus = 0;
1243 	callout_schedule(&sc->xmt_asense_co, MIDI_XMT_ASENSE_PERIOD);
1244 	MIDI_OUT_UNLOCK(sc,s);
1245 	return error;
1246 }
1247 
1248 /*
1249  * The interrupt flavor acquires spl and lock once and releases at the end,
1250  * as it expects to write only one byte or message. The interface convention
1251  * is that if hw_if->output returns 0, it has initiated transmission and the
1252  * completion interrupt WILL be forthcoming; if it has not returned 0, NO
1253  * interrupt will be forthcoming, and if it returns EINPROGRESS it wants
1254  * another byte right away.
1255  */
1256 int
1257 midi_intr_out(struct midi_softc *sc)
1258 {
1259 	struct midi_buffer *mb = &sc->outbuf;
1260 	int error;
1261 	int msglen;
1262 	int s;
1263 	MIDI_BUF_DECLARE(idx);
1264 	MIDI_BUF_DECLARE(buf);
1265 	int armed = 0;
1266 
1267 	error = 0;
1268 
1269 	MIDI_OUT_LOCK(sc,s);
1270 	MIDI_BUF_CONSUMER_INIT(mb,idx);
1271 	MIDI_BUF_CONSUMER_INIT(mb,buf);
1272 
1273 	while ( idx_cur != idx_lim ) {
1274 		if ( sc->hw_if_ext ) {
1275 			error = midi_msg_out(sc, &idx_cur, &idx_lim,
1276 				                 &buf_cur, &buf_lim);
1277 			if ( !error ) /* no EINPROGRESS from extended hw_if */
1278 				armed = 1;
1279 			break;
1280 		}
1281 		/* or, lacking hw_if_ext ... */
1282 		msglen = MB_IDX_LEN(*idx_cur);
1283 		error = sc->hw_if->output(sc->hw_hdl, *buf_cur);
1284 		if ( error  &&  error != EINPROGRESS )
1285 			break;
1286 		++ buf_cur;
1287 		MIDI_BUF_WRAP(buf);
1288 		-- msglen;
1289 		if ( msglen )
1290 			*idx_cur = PACK_MB_IDX(MB_IDX_CAT(*idx_cur),msglen);
1291 		else {
1292 			++ idx_cur;
1293 			MIDI_BUF_WRAP(idx);
1294 		}
1295 		if ( !error ) {
1296 			armed = 1;
1297 			break;
1298 		}
1299 	}
1300 	MIDI_BUF_CONSUMER_WBACK(mb,idx);
1301 	MIDI_BUF_CONSUMER_WBACK(mb,buf);
1302 	if ( !armed ) {
1303 		sc->pbus = 0;
1304 		callout_schedule(&sc->xmt_asense_co, MIDI_XMT_ASENSE_PERIOD);
1305 	}
1306 	MIDI_OUT_UNLOCK(sc,s);
1307 	softint_schedule(sc->sih_wr);
1308 
1309 #if defined(AUDIO_DEBUG) || defined(DIAGNOSTIC)
1310 	if ( error )
1311 		aprint_error_dev(sc->dev, "midi_intr_output error %d\n",
1312 		    error);
1313 #endif
1314 	return error;
1315 }
1316 
1317 int
1318 midi_start_output(struct midi_softc *sc)
1319 {
1320 	if (sc->dying)
1321 		return EIO;
1322 
1323 	if ( sc->props & MIDI_PROP_OUT_INTR )
1324 		return midi_intr_out(sc);
1325 	return midi_poll_out(sc);
1326 }
1327 
1328 static int
1329 real_writebytes(struct midi_softc *sc, u_char *ibuf, int cc)
1330 {
1331 	u_char *iend = ibuf + cc;
1332 	struct midi_buffer *mb = &sc->outbuf;
1333 	int arming = 0;
1334 	int count;
1335 	int s;
1336 	int got;
1337 	enum fst_form form;
1338 	MIDI_BUF_DECLARE(idx);
1339 	MIDI_BUF_DECLARE(buf);
1340 
1341 	/*
1342 	 * If the hardware uses the extended hw_if, pass it canonicalized
1343 	 * messages (or compressed ones if it specifically requests, using
1344 	 * VCOMP form so the bottom half can still pass the op and chan along);
1345 	 * if it does not, send it compressed messages (using COMPR form as
1346 	 * there is no need to preserve the status for the bottom half).
1347 	 */
1348 	if ( NULL == sc->hw_if_ext )
1349 		form = FST_COMPR;
1350 	else if ( sc->hw_if_ext->compress )
1351 		form = FST_VCOMP;
1352 	else
1353 		form = FST_CANON;
1354 
1355 	MIDI_OUT_LOCK(sc,s);
1356 	MIDI_BUF_PRODUCER_INIT(mb,idx);
1357 	MIDI_BUF_PRODUCER_INIT(mb,buf);
1358 	MIDI_OUT_UNLOCK(sc,s);
1359 
1360 	if (sc->dying)
1361 		return EIO;
1362 
1363 	while ( ibuf < iend ) {
1364 		got = midi_fst(&sc->xmt, *ibuf, form);
1365 		++ ibuf;
1366 		switch ( got ) {
1367 		case FST_MORE:
1368 			continue;
1369 		case FST_ERR:
1370 		case FST_HUH:
1371 			return EPROTO;
1372 		case FST_CHN:
1373 		case FST_CHV: /* only occurs in VCOMP form */
1374 		case FST_COM:
1375 		case FST_RT:
1376 		case FST_SYX:
1377 		case FST_SXP:
1378 			break; /* go add to buffer */
1379 #if defined(AUDIO_DEBUG) || defined(DIAGNOSTIC)
1380 		default:
1381 			printf("midi_wr: midi_fst returned %d?!\n", got);
1382 #endif
1383 		}
1384 		count = sc->xmt.end - sc->xmt.pos;
1385 		if ( 0 == count ) /* can happen with stray 0xf7; see midi_fst */
1386 			continue;
1387 		/*
1388 		 * return EWOULDBLOCK if the data passed will not fit in
1389 		 * the buffer; the caller should have taken steps to avoid that.
1390 		 * If got==FST_SXP we lose the new status byte, but we're losing
1391 		 * anyway, so c'est la vie.
1392 		 */
1393 		if ( idx_cur == idx_lim || count > buf_lim - buf_cur ) {
1394 			MIDI_OUT_LOCK(sc,s);
1395 			MIDI_BUF_PRODUCER_REFRESH(mb,idx); /* get the most */
1396 			MIDI_BUF_PRODUCER_REFRESH(mb,buf); /*  current facts */
1397 			MIDI_OUT_UNLOCK(sc,s);
1398 			if ( idx_cur == idx_lim || count > buf_lim - buf_cur )
1399 				return EWOULDBLOCK; /* caller's problem */
1400 		}
1401 		*idx_cur++ = PACK_MB_IDX(got,count);
1402 		MIDI_BUF_WRAP(idx);
1403 		while ( count ) {
1404 			*buf_cur++ = *(sc->xmt.pos)++;
1405 			MIDI_BUF_WRAP(buf);
1406 			-- count;
1407 		}
1408 		if ( FST_SXP == got )
1409 			-- ibuf; /* again with same status byte */
1410 	}
1411 	MIDI_OUT_LOCK(sc,s);
1412 	MIDI_BUF_PRODUCER_WBACK(mb,buf);
1413 	MIDI_BUF_PRODUCER_WBACK(mb,idx);
1414 	/*
1415 	 * If the output transfer is not already busy, and there is a message
1416 	 * buffered, mark it busy, stop the Active Sense callout (what if we're
1417 	 * too late and it's expired already? No big deal, an extra Active Sense
1418 	 * never hurt anybody) and start the output transfer once we're out of
1419 	 * the critical section (pbus==1 will stop anyone else doing the same).
1420 	 */
1421 	MIDI_BUF_CONSUMER_INIT(mb,idx); /* check what consumer's got to read */
1422 	if ( !sc->pbus && idx_cur < idx_lim ) {
1423 		sc->pbus = 1;
1424 		callout_stop(&sc->xmt_asense_co);
1425 		arming = 1;
1426 	}
1427 	MIDI_OUT_UNLOCK(sc,s);
1428 	return arming ? midi_start_output(sc) : 0;
1429 }
1430 
1431 int
1432 midiwrite(dev_t dev, struct uio *uio, int ioflag)
1433 {
1434 	struct midi_softc *sc =
1435 	    device_lookup_private(&midi_cd, MIDIUNIT(dev));
1436 	struct midi_buffer *mb = &sc->outbuf;
1437 	int error;
1438 	u_char inp[256];
1439 	int s;
1440 	MIDI_BUF_DECLARE(idx);
1441 	MIDI_BUF_DECLARE(buf);
1442 	size_t idxspace;
1443 	size_t bufspace;
1444 	size_t xfrcount;
1445 	int pollout = 0;
1446 
1447 	DPRINTFN(6, ("midiwrite: %p, unit=%d, count=%lu\n", sc, (int)minor(dev),
1448 		     (unsigned long)uio->uio_resid));
1449 
1450 	if (sc->dying)
1451 		return EIO;
1452 
1453 	error = 0;
1454 	while (uio->uio_resid > 0 && !error) {
1455 
1456 		/*
1457 		 * block if necessary for the minimum buffer space to guarantee
1458 		 * we can write something.
1459 		 */
1460 		MIDI_OUT_LOCK(sc,s);
1461 		MIDI_BUF_PRODUCER_INIT(mb,idx); /* init can't go above loop; */
1462 		MIDI_BUF_PRODUCER_INIT(mb,buf); /* real_writebytes moves cur */
1463 		for ( ;; ) {
1464 			idxspace = MIDI_BUF_PRODUCER_REFRESH(mb,idx) - idx_cur;
1465 			bufspace = MIDI_BUF_PRODUCER_REFRESH(mb,buf) - buf_cur;
1466 			if ( idxspace >= 1  &&  bufspace >= 3  && !pollout )
1467 				break;
1468 			DPRINTFN(8,("midi_write: sleep idx=%zd buf=%zd\n",
1469 				 idxspace, bufspace));
1470 			if (ioflag & IO_NDELAY) {
1471 				error = EWOULDBLOCK;
1472 				/*
1473 				 * If some amount has already been transferred,
1474 				 * the common syscall code will automagically
1475 				 * convert this to success with a short count.
1476 				 */
1477 				goto locked_exit;
1478 			}
1479 			if ( pollout ) {
1480 				preempt(); /* see midi_poll_output */
1481 				pollout = 0;
1482 			} else
1483 				error = midi_sleep(&sc->wchan, "mid wr",
1484 				                   &sc->out_lock);
1485 			if (error)
1486 				/*
1487 				 * Similarly, the common code will handle
1488 				 * EINTR and ERESTART properly here, changing to
1489 				 * a short count if something transferred.
1490 				 */
1491 				goto locked_exit;
1492 		}
1493 		MIDI_OUT_UNLOCK(sc,s);
1494 
1495 		/*
1496 		 * The number of bytes we can safely extract from the uio
1497 		 * depends on the available idx and buf space. Worst case,
1498 		 * every byte is a message so 1 idx is required per byte.
1499 		 * Worst case, the first byte completes a 3-byte msg in prior
1500 		 * state, and every subsequent byte is a Program Change or
1501 		 * Channel Pressure msg with running status and expands to 2
1502 		 * bytes, so the buf space reqd is 3+2(n-1) or 2n+1. So limit
1503 		 * the transfer to the min of idxspace and (bufspace-1)>>1.
1504 		 */
1505 		xfrcount = (bufspace - 1) >> 1;
1506 		if ( xfrcount > idxspace )
1507 			xfrcount = idxspace;
1508 		if ( xfrcount > sizeof inp )
1509 			xfrcount = sizeof inp;
1510 		if ( xfrcount > uio->uio_resid )
1511 			xfrcount = uio->uio_resid;
1512 
1513 		error = uiomove(inp, xfrcount, uio);
1514 #ifdef MIDI_DEBUG
1515 		if (error)
1516 		        printf("midi_write:(1) uiomove failed %d; "
1517 			       "xfrcount=%d inp=%p\n",
1518 			       error, xfrcount, inp);
1519 #endif
1520 		if ( error )
1521 			break;
1522 
1523 		/*
1524 		 * The number of bytes we extracted being calculated to
1525 		 * definitely fit in the buffer even with canonicalization,
1526 		 * there is no excuse for real_writebytes to return EWOULDBLOCK.
1527 		 */
1528 		error = real_writebytes(sc, inp, xfrcount);
1529 		KASSERT(error != EWOULDBLOCK);
1530 
1531 		if ( error )
1532 			break;
1533 		/*
1534 		 * If this is a polling device and we just sent a buffer, let's
1535 		 * not send another without giving some other process a chance.
1536 		 */
1537 		if ( ! (sc->props & MIDI_PROP_OUT_INTR) )
1538 			pollout = 1;
1539 		DPRINTFN(8,("midiwrite: uio_resid now %zu, props=%d\n",
1540                         uio->uio_resid, sc->props));
1541 	}
1542 	return error;
1543 
1544 locked_exit:
1545 	MIDI_OUT_UNLOCK(sc,s);
1546 	return error;
1547 }
1548 
1549 /*
1550  * This write routine is only called from sequencer code and expects
1551  * a write that is smaller than the MIDI buffer.
1552  */
1553 int
1554 midi_writebytes(int unit, u_char *bf, int cc)
1555 {
1556 	struct midi_softc *sc =
1557 	    device_lookup_private(&midi_cd, unit);
1558 
1559 	DPRINTFN(7, ("midi_writebytes: %p, unit=%d, cc=%d %#02x %#02x %#02x\n",
1560                     sc, unit, cc, bf[0], bf[1], bf[2]));
1561 	return real_writebytes(sc, bf, cc);
1562 }
1563 
1564 int
1565 midiioctl(dev_t dev, u_long cmd, void *addr, int flag, struct lwp *l)
1566 {
1567 	struct midi_softc *sc =
1568 	    device_lookup_private(&midi_cd, MIDIUNIT(dev));
1569 	const struct midi_hw_if *hw = sc->hw_if;
1570 	int error;
1571 	int s;
1572 	MIDI_BUF_DECLARE(buf);
1573 
1574 	DPRINTFN(5,("midiioctl: %p cmd=0x%08lx\n", sc, cmd));
1575 
1576 	if (sc->dying)
1577 		return EIO;
1578 
1579 	error = 0;
1580 	switch (cmd) {
1581 	case FIONBIO:
1582 		/* All handled in the upper FS layer. */
1583 		break;
1584 
1585 	case FIONREAD:
1586 		/*
1587 		 * This code relies on the current implementation of midi_in
1588 		 * always updating buf and idx together in a critical section,
1589 		 * so buf always ends at a message boundary. Document this
1590 		 * ioctl as always returning a value such that the last message
1591 		 * included is complete (SysEx the only exception), and then
1592 		 * make sure the implementation doesn't regress.  NB that
1593 		 * means if this ioctl returns n and the proc then issues a
1594 		 * read of n, n bytes will be read, but if the proc issues a
1595 		 * read of m < n, fewer than m bytes may be read to ensure the
1596 		 * read ends at a message boundary.
1597 		 */
1598 		MIDI_IN_LOCK(sc,s);
1599 		MIDI_BUF_CONSUMER_INIT(&sc->inbuf,buf);
1600 		MIDI_IN_UNLOCK(sc,s);
1601 		*(int *)addr = buf_lim - buf_cur;
1602 		break;
1603 
1604 	case FIOASYNC:
1605 		if (*(int *)addr) {
1606 			if (sc->async)
1607 				return EBUSY;
1608 			sc->async = l->l_proc;
1609 			DPRINTFN(5,("midi_ioctl: FIOASYNC %p\n", l->l_proc));
1610 		} else
1611 			sc->async = 0;
1612 		break;
1613 
1614 #if 0
1615 	case MIDI_PRETIME:
1616 		/* XXX OSS
1617 		 * This should set up a read timeout, but that's
1618 		 * why we have poll(), so there's nothing yet. */
1619 		error = EINVAL;
1620 		break;
1621 #endif
1622 
1623 #ifdef MIDI_SAVE
1624 	case MIDI_GETSAVE:
1625 		error = copyout(&midisave, *(void **)addr, sizeof midisave);
1626   		break;
1627 #endif
1628 
1629 	default:
1630 		if (hw->ioctl)
1631 			error = hw->ioctl(sc->hw_hdl, cmd, addr, flag, l);
1632 		else
1633 			error = EINVAL;
1634 		break;
1635 	}
1636 	return error;
1637 }
1638 
1639 int
1640 midipoll(dev_t dev, int events, struct lwp *l)
1641 {
1642 	struct midi_softc *sc =
1643 	    device_lookup_private(&midi_cd, MIDIUNIT(dev));
1644 	int revents = 0;
1645 	int s;
1646 	MIDI_BUF_DECLARE(idx);
1647 	MIDI_BUF_DECLARE(buf);
1648 
1649 	DPRINTFN(6,("midipoll: %p events=0x%x\n", sc, events));
1650 
1651 	if (sc->dying)
1652 		return POLLHUP;
1653 
1654 	s = splaudio();
1655 
1656 	if ((sc->flags&FREAD) && (events & (POLLIN | POLLRDNORM))) {
1657 		simple_lock(&sc->in_lock);
1658 		MIDI_BUF_CONSUMER_INIT(&sc->inbuf,idx);
1659 		if (idx_cur < idx_lim)
1660 			revents |= events & (POLLIN | POLLRDNORM);
1661 		else
1662 			selrecord(l, &sc->rsel);
1663 		simple_unlock(&sc->in_lock);
1664 	}
1665 
1666 	if ((sc->flags&FWRITE) && (events & (POLLOUT | POLLWRNORM))) {
1667 		simple_lock(&sc->out_lock);
1668 		MIDI_BUF_PRODUCER_INIT(&sc->outbuf,idx);
1669 		MIDI_BUF_PRODUCER_INIT(&sc->outbuf,buf);
1670 		if ( idx_lim - idx_cur >= 1  &&  buf_lim - buf_cur >= 3 )
1671 			revents |= events & (POLLOUT | POLLWRNORM);
1672 		else
1673 			selrecord(l, &sc->wsel);
1674 		simple_unlock(&sc->out_lock);
1675 	}
1676 
1677 	splx(s);
1678 	return revents;
1679 }
1680 
1681 static void
1682 filt_midirdetach(struct knote *kn)
1683 {
1684 	struct midi_softc *sc = kn->kn_hook;
1685 	int s;
1686 
1687 	s = splaudio();
1688 	SLIST_REMOVE(&sc->rsel.sel_klist, kn, knote, kn_selnext);
1689 	splx(s);
1690 }
1691 
1692 static int
1693 filt_midiread(struct knote *kn, long hint)
1694 {
1695 	struct midi_softc *sc = kn->kn_hook;
1696 	int s;
1697 	MIDI_BUF_DECLARE(buf);
1698 
1699 	/* XXXLUKEM (thorpej): please make sure this is correct. */
1700 
1701 	MIDI_IN_LOCK(sc,s);
1702 	MIDI_BUF_CONSUMER_INIT(&sc->inbuf,buf);
1703 	kn->kn_data = buf_lim - buf_cur;
1704 	MIDI_IN_UNLOCK(sc,s);
1705 	return (kn->kn_data > 0);
1706 }
1707 
1708 static const struct filterops midiread_filtops =
1709 	{ 1, NULL, filt_midirdetach, filt_midiread };
1710 
1711 static void
1712 filt_midiwdetach(struct knote *kn)
1713 {
1714 	struct midi_softc *sc = kn->kn_hook;
1715 	int s;
1716 
1717 	s = splaudio();
1718 	SLIST_REMOVE(&sc->wsel.sel_klist, kn, knote, kn_selnext);
1719 	splx(s);
1720 }
1721 
1722 static int
1723 filt_midiwrite(struct knote *kn, long hint)
1724 {
1725 	struct midi_softc *sc = kn->kn_hook;
1726 	int s;
1727 	MIDI_BUF_DECLARE(idx);
1728 	MIDI_BUF_DECLARE(buf);
1729 
1730 	/* XXXLUKEM (thorpej): please make sure this is correct. */
1731 
1732 	MIDI_OUT_LOCK(sc,s);
1733 	MIDI_BUF_PRODUCER_INIT(&sc->outbuf,idx);
1734 	MIDI_BUF_PRODUCER_INIT(&sc->outbuf,buf);
1735 	kn->kn_data = ((buf_lim - buf_cur)-1)>>1;
1736 	if ( kn->kn_data > idx_lim - idx_cur )
1737 		kn->kn_data = idx_lim - idx_cur;
1738 	MIDI_OUT_UNLOCK(sc,s);
1739 	return (kn->kn_data > 0);
1740 }
1741 
1742 static const struct filterops midiwrite_filtops =
1743 	{ 1, NULL, filt_midiwdetach, filt_midiwrite };
1744 
1745 int
1746 midikqfilter(dev_t dev, struct knote *kn)
1747 {
1748 	struct midi_softc *sc =
1749 	    device_lookup_private(&midi_cd, MIDIUNIT(dev));
1750 	struct klist *klist;
1751 	int s;
1752 
1753 	switch (kn->kn_filter) {
1754 	case EVFILT_READ:
1755 		klist = &sc->rsel.sel_klist;
1756 		kn->kn_fop = &midiread_filtops;
1757 		break;
1758 
1759 	case EVFILT_WRITE:
1760 		klist = &sc->wsel.sel_klist;
1761 		kn->kn_fop = &midiwrite_filtops;
1762 		break;
1763 
1764 	default:
1765 		return (EINVAL);
1766 	}
1767 
1768 	kn->kn_hook = sc;
1769 
1770 	s = splaudio();
1771 	SLIST_INSERT_HEAD(klist, kn, kn_selnext);
1772 	splx(s);
1773 
1774 	return (0);
1775 }
1776 
1777 void
1778 midi_getinfo(dev_t dev, struct midi_info *mi)
1779 {
1780 	struct midi_softc *sc;
1781 
1782 	sc = device_lookup_private(&midi_cd, MIDIUNIT(dev));
1783 	if (sc == NULL)
1784 		return;
1785 	if (sc->dying)
1786 		return;
1787 
1788 	sc->hw_if->getinfo(sc->hw_hdl, mi);
1789 }
1790 
1791 #elif NMIDIBUS > 0 /* but NMIDI == 0 */
1792 
1793 void midi_register_hw_if_ext(struct midi_hw_if_ext *exthw) { /* stub */
1794 }
1795 
1796 #endif /* NMIDI > 0 */
1797 
1798 #if NMIDI > 0 || NMIDIBUS > 0
1799 
1800 int	audioprint(void *, const char *);
1801 
1802 device_t
1803 midi_attach_mi(const struct midi_hw_if *mhwp, void *hdlp, device_t dev)
1804 {
1805 	struct audio_attach_args arg;
1806 
1807 #ifdef DIAGNOSTIC
1808 	if (mhwp == NULL) {
1809 		aprint_error("midi_attach_mi: NULL\n");
1810 		return (0);
1811 	}
1812 #endif
1813 	arg.type = AUDIODEV_TYPE_MIDI;
1814 	arg.hwif = mhwp;
1815 	arg.hdl = hdlp;
1816 	return (config_found(dev, &arg, audioprint));
1817 }
1818 
1819 #endif /* NMIDI > 0 || NMIDIBUS > 0 */
1820