xref: /netbsd-src/sys/dev/midi.c (revision 267197ec1eebfcb9810ea27a89625b6ddf68e3e7)
1 /*	$NetBSD: midi.c,v 1.59 2007/12/16 19:01:35 christos 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 1.59 2007/12/16 19:01:35 christos 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 #include <sys/intr.h>
63 
64 #include <dev/audio_if.h>
65 #include <dev/midi_if.h>
66 #include <dev/midivar.h>
67 
68 #if NMIDI > 0
69 
70 #ifdef AUDIO_DEBUG
71 #define DPRINTF(x)	if (mididebug) printf x
72 #define DPRINTFN(n,x)	if (mididebug >= (n)) printf x
73 int	mididebug = 0;
74 /*
75  *      1: detected protocol errors and buffer overflows
76  *      2: probe, attach, detach
77  *      3: open, close
78  *      4: data received except realtime
79  *      5: ioctl
80  *      6: read, write, poll
81  *      7: data transmitted
82  *      8: uiomoves, synchronization
83  *      9: realtime data received
84  */
85 #else
86 #define DPRINTF(x)
87 #define DPRINTFN(n,x)
88 #endif
89 
90 static	struct simplelock hwif_register_lock = SIMPLELOCK_INITIALIZER;
91 static	struct midi_softc *hwif_softc = NULL;
92 
93 void	midi_in(void *, int);
94 void	midi_out(void *);
95 int     midi_poll_out(struct midi_softc *);
96 int     midi_intr_out(struct midi_softc *);
97 int 	midi_msg_out(struct midi_softc *,
98                  u_char **, u_char **, u_char **, u_char **);
99 int	midi_start_output(struct midi_softc *);
100 int	midi_sleep_timo(int *, const char *, int, struct simplelock *);
101 int	midi_sleep(int *, const char *, struct simplelock *);
102 void	midi_wakeup(int *);
103 void	midi_initbuf(struct midi_buffer *);
104 void	midi_xmt_asense(void *);
105 void	midi_rcv_asense(void *);
106 void	midi_softintr_rd(void *);
107 void	midi_softintr_wr(void *);
108 
109 int	midiprobe(struct device *, struct cfdata *, void *);
110 void	midiattach(struct device *, struct device *, void *);
111 int	mididetach(struct device *, int);
112 int	midiactivate(struct device *, enum devact);
113 
114 dev_type_open(midiopen);
115 dev_type_close(midiclose);
116 dev_type_read(midiread);
117 dev_type_write(midiwrite);
118 dev_type_ioctl(midiioctl);
119 dev_type_poll(midipoll);
120 dev_type_kqfilter(midikqfilter);
121 
122 const struct cdevsw midi_cdevsw = {
123 	midiopen, midiclose, midiread, midiwrite, midiioctl,
124 	nostop, notty, midipoll, nommap, midikqfilter, D_OTHER,
125 };
126 
127 CFATTACH_DECL(midi, sizeof(struct midi_softc),
128     midiprobe, midiattach, mididetach, midiactivate);
129 
130 #define MIDI_XMT_ASENSE_PERIOD mstohz(275)
131 #define MIDI_RCV_ASENSE_PERIOD mstohz(300)
132 
133 extern struct cfdriver midi_cd;
134 
135 int
136 midiprobe(struct device *parent, struct cfdata *match,
137     void *aux)
138 {
139 	struct audio_attach_args *sa = aux;
140 
141 	DPRINTFN(2,("midiprobe: type=%d sa=%p hw=%p\n",
142 		 sa->type, sa, sa->hwif));
143 	return (sa->type == AUDIODEV_TYPE_MIDI);
144 }
145 
146 void
147 midiattach(struct device *parent, struct device *self, void *aux)
148 {
149 	struct midi_softc *sc = (void *)self;
150 	struct audio_attach_args *sa = aux;
151 	const struct midi_hw_if *hwp = sa->hwif;
152 	void *hdlp = sa->hdl;
153 
154 	aprint_naive("\n");
155 
156 	DPRINTFN(2, ("MIDI attach\n"));
157 
158 #ifdef DIAGNOSTIC
159 	if (hwp == 0 ||
160 	    hwp->open == 0 ||
161 	    hwp->close == 0 ||
162 	    hwp->output == 0 ||
163 	    hwp->getinfo == 0) {
164 		printf("midi: missing method\n");
165 		return;
166 	}
167 #endif
168 
169 	sc->hw_if = hwp;
170 	sc->hw_hdl = hdlp;
171 	midi_attach(sc, parent);
172         if (!device_pmf_is_registered(self))
173 		if (!pmf_device_register(self, NULL, NULL))
174 			aprint_error_dev(self,
175 			    "couldn't establish power handler\n");
176 }
177 
178 int
179 midiactivate(struct device *self, enum devact act)
180 {
181 	struct midi_softc *sc = (struct midi_softc *)self;
182 
183 	switch (act) {
184 	case DVACT_ACTIVATE:
185 		return (EOPNOTSUPP);
186 
187 	case DVACT_DEACTIVATE:
188 		sc->dying = 1;
189 		break;
190 	}
191 	return (0);
192 }
193 
194 int
195 mididetach(struct device *self, int flags)
196 {
197 	struct midi_softc *sc = (struct midi_softc *)self;
198 	int maj, mn;
199 
200 	DPRINTFN(2,("midi_detach: sc=%p flags=%d\n", sc, flags));
201 
202 	pmf_device_deregister(self);
203 
204 	sc->dying = 1;
205 
206 	wakeup(&sc->wchan);
207 	wakeup(&sc->rchan);
208 
209 	/* locate the major number */
210 	maj = cdevsw_lookup_major(&midi_cdevsw);
211 
212 	/* Nuke the vnodes for any open instances (calls close). */
213 	mn = device_unit(self);
214 	vdevgone(maj, mn, mn, VCHR);
215 
216 	if ( !(sc->props & MIDI_PROP_NO_OUTPUT) ) {
217 		evcnt_detach(&sc->xmt.bytesDiscarded);
218 		evcnt_detach(&sc->xmt.incompleteMessages);
219 	}
220 	if ( sc->props & MIDI_PROP_CAN_INPUT ) {
221 		evcnt_detach(&sc->rcv.bytesDiscarded);
222 		evcnt_detach(&sc->rcv.incompleteMessages);
223 	}
224 
225 	if (sc->sih_rd != NULL) {
226 		softint_disestablish(sc->sih_rd);
227 		sc->sih_rd = NULL;
228 	}
229 	if (sc->sih_wr != NULL) {
230 		softint_disestablish(sc->sih_wr);
231 		sc->sih_wr = NULL;
232 	}
233 
234 	return (0);
235 }
236 
237 void
238 midi_attach(struct midi_softc *sc, struct device *parent)
239 {
240 	struct midi_info mi;
241 	int s;
242 
243 	callout_init(&sc->xmt_asense_co, 0);
244 	callout_init(&sc->rcv_asense_co, 0);
245 	callout_setfunc(&sc->xmt_asense_co, midi_xmt_asense, sc);
246 	callout_setfunc(&sc->rcv_asense_co, midi_rcv_asense, sc);
247 	simple_lock_init(&sc->out_lock);
248 	simple_lock_init(&sc->in_lock);
249 	sc->dying = 0;
250 	sc->isopen = 0;
251 
252 	sc->sc_dev = parent;
253 
254 	sc->sih_rd = softint_establish(SOFTINT_SERIAL, midi_softintr_rd, sc);
255 	sc->sih_wr = softint_establish(SOFTINT_SERIAL, midi_softintr_wr, sc);
256 
257 	s = splaudio();
258 	simple_lock(&hwif_register_lock);
259 	hwif_softc = sc;
260 	sc->hw_if->getinfo(sc->hw_hdl, &mi);
261 	hwif_softc = NULL;
262 	simple_unlock(&hwif_register_lock);
263 	splx(s);
264 
265 	sc->props = mi.props;
266 
267 	if ( !(sc->props & MIDI_PROP_NO_OUTPUT) ) {
268 		evcnt_attach_dynamic(&sc->xmt.bytesDiscarded,
269 			EVCNT_TYPE_MISC, NULL,
270 			sc->dev.dv_xname, "xmt bytes discarded");
271 		evcnt_attach_dynamic(&sc->xmt.incompleteMessages,
272 			EVCNT_TYPE_MISC, NULL,
273 			sc->dev.dv_xname, "xmt incomplete msgs");
274 	}
275 	if ( sc->props & MIDI_PROP_CAN_INPUT ) {
276 		evcnt_attach_dynamic(&sc->rcv.bytesDiscarded,
277 			EVCNT_TYPE_MISC, NULL,
278 			sc->dev.dv_xname, "rcv bytes discarded");
279 		evcnt_attach_dynamic(&sc->rcv.incompleteMessages,
280 			EVCNT_TYPE_MISC, NULL,
281 			sc->dev.dv_xname, "rcv incomplete msgs");
282 	}
283 
284 	aprint_normal(": %s%s\n", mi.name,
285 	    (sc->props & (MIDI_PROP_OUT_INTR|MIDI_PROP_NO_OUTPUT)) ?
286 	    "" : " (CPU-intensive output)");
287 }
288 
289 void midi_register_hw_if_ext(struct midi_hw_if_ext *exthw) {
290 	if ( hwif_softc != NULL ) /* ignore calls resulting from non-init */
291 		hwif_softc->hw_if_ext = exthw; /* uses of getinfo */
292 }
293 
294 int
295 midi_unit_count(void)
296 {
297 	int i;
298 	for ( i = 0; i < midi_cd.cd_ndevs; ++i )
299 	        if ( NULL == midi_cd.cd_devs[i] )
300 		        break;
301         return i;
302 }
303 
304 void
305 midi_initbuf(struct midi_buffer *mb)
306 {
307 	mb->idx_producerp = mb->idx_consumerp = mb->idx;
308 	mb->buf_producerp = mb->buf_consumerp = mb->buf;
309 }
310 #define PACK_MB_IDX(cat,len) (((cat)<<4)|(len))
311 #define MB_IDX_CAT(idx) ((idx)>>4)
312 #define MB_IDX_LEN(idx) ((idx)&0xf)
313 
314 int
315 midi_sleep_timo(int *chan, const char *label, int timo, struct simplelock *lk)
316 {
317 	int st;
318 
319 	if (!label)
320 		label = "midi";
321 
322 	DPRINTFN(8, ("midi_sleep_timo: %p %s %d\n", chan, label, timo));
323 	*chan = 1;
324 	st = ltsleep(chan, PWAIT | PCATCH, label, timo, lk);
325 	*chan = 0;
326 #ifdef MIDI_DEBUG
327 	if (st != 0)
328 		printf("midi_sleep: %d\n", st);
329 #endif
330 	return st;
331 }
332 
333 int
334 midi_sleep(int *chan, const char *label, struct simplelock *lk)
335 {
336 	return midi_sleep_timo(chan, label, 0, lk);
337 }
338 
339 void
340 midi_wakeup(int *chan)
341 {
342 	if (*chan) {
343 		DPRINTFN(8, ("midi_wakeup: %p\n", chan));
344 		wakeup(chan);
345 		*chan = 0;
346 	}
347 }
348 
349 /* in midivar.h:
350 #define MIDI_CAT_DATA 0
351 #define MIDI_CAT_STATUS1 1
352 #define MIDI_CAT_STATUS2 2
353 #define MIDI_CAT_COMMON 3
354 */
355 static char const midi_cats[] = "\0\0\0\0\0\0\0\0\2\2\2\2\1\1\2\3";
356 #define MIDI_CAT(d) (midi_cats[((d)>>4)&15])
357 #define FST_RETURN(offp,endp,ret) \
358 	return (s->pos=s->msg+(offp)), (s->end=s->msg+(endp)), (ret)
359 
360 enum fst_ret { FST_CHN, FST_CHV, FST_COM, FST_SYX, FST_RT, FST_MORE, FST_ERR,
361                FST_HUH, FST_SXP };
362 enum fst_form { FST_CANON, FST_COMPR, FST_VCOMP };
363 static struct {
364 	int off;
365 	enum fst_ret tag;
366 } const midi_forms[] = {
367 	[FST_CANON] = { .off=0, .tag=FST_CHN },
368 	[FST_COMPR] = { .off=1, .tag=FST_CHN },
369 	[FST_VCOMP] = { .off=0, .tag=FST_CHV }
370 };
371 #define FST_CRETURN(endp) \
372 	FST_RETURN(midi_forms[form].off,endp,midi_forms[form].tag)
373 
374 /*
375  * A MIDI finite state transducer suitable for receiving or transmitting. It
376  * will accept correct MIDI input that uses, doesn't use, or sometimes uses the
377  * 'running status' compression technique, and transduce it to fully expanded
378  * (form=FST_CANON) or fully compressed (form=FST_COMPR or FST_VCOMP) form.
379  *
380  * Returns FST_MORE if a complete message has not been parsed yet (SysEx
381  * messages are the exception), FST_ERR or FST_HUH if the input does not
382  * conform to the protocol, or FST_CHN (channel messages), FST_COM (System
383  * Common messages), FST_RT (System Real-Time messages), or FST_SYX (System
384  * Exclusive) to broadly categorize the message parsed. s->pos and s->end
385  * locate the parsed message; while (s->pos<s->end) putchar(*(s->pos++));
386  * would output it.
387  *
388  * FST_HUH means the character c wasn't valid in the original state, but the
389  * state has now been reset to START and the caller should try again passing
390  * the same c. FST_ERR means c isn't valid in the start state; the caller
391  * should kiss it goodbye and continue to try successive characters from the
392  * input until something other than FST_ERR or FST_HUH is returned, at which
393  * point things are resynchronized.
394  *
395  * A FST_SYX return means that between pos and end are from 1 to 3
396  * bytes of a system exclusive message. A SysEx message will be delivered in
397  * one or more chunks of that form, where the first begins with 0xf0 and the
398  * last (which is the only one that might have length < 3) ends with 0xf7.
399  *
400  * Messages corrupted by a protocol error are discarded and won't be seen at
401  * all; again SysEx is the exception, as one or more chunks of it may already
402  * have been parsed.
403  *
404  * For FST_CHN messages, s->msg[0] always contains the status byte even if
405  * FST_COMPR form was requested (pos then points to msg[1]). That way, the
406  * caller can always identify the exact message if there is a need to do so.
407  * For all other message types except FST_SYX, the status byte is at *pos
408  * (which may not necessarily be msg[0]!). There is only one SysEx status
409  * byte, so the return value FST_SYX is sufficient to identify it.
410  *
411  * To simplify some use cases, compression can also be requested with
412  * form=FST_VCOMP. In this form a compressible channel message is indicated
413  * by returning a classification of FST_CHV instead of FST_CHN, and pos points
414  * to the status byte rather than being advanced past it. If the caller in this
415  * case saves the bytes from pos to end, it will have saved the entire message,
416  * and can act on the FST_CHV tag to drop the first byte later. In this form,
417  * unlike FST_CANON, hidden note-off (i.e. note-on with velocity 0) may occur.
418  *
419  * Two obscure points in the MIDI protocol complicate things further, both to
420  * do with the EndSysEx code, 0xf7. First, this code is permitted (and
421  * meaningless) outside of a System Exclusive message, anywhere a status byte
422  * could appear. Second, it is allowed to be absent at the end of a System
423  * Exclusive message (!) - any status byte at all (non-realtime) is allowed to
424  * terminate the message. Both require accomodation in the interface to
425  * midi_fst's caller. A stray 0xf7 should be ignored BUT should count as a
426  * message received for purposes of Active Sense timeout; the case is
427  * represented by a return of FST_COM with a length of zero (pos == end). A
428  * status byte other than 0xf7 during a system exclusive message will cause an
429  * FST_SXP (sysex plus) return; the bytes from pos to end are the end of the
430  * system exclusive message, and after handling those the caller should call
431  * midi_fst again with the same input byte.
432  *
433  * midi(4) will never produce either such form of rubbish.
434  */
435 static enum fst_ret
436 midi_fst(struct midi_state *s, u_char c, enum fst_form form)
437 {
438 	int syxpos = 0;
439 
440 	if ( c >= 0xf8 ) { /* All realtime messages bypass state machine */
441 	        if ( c == 0xf9  ||  c == 0xfd ) {
442 			DPRINTF( ("midi_fst: s=%p c=0x%02x undefined\n",
443 				  s, c));
444 			s->bytesDiscarded.ev_count++;
445 			return FST_ERR;
446 		}
447 		DPRINTFN(9, ("midi_fst: s=%p System Real-Time data=0x%02x\n",
448 			     s, c));
449 		s->msg[2] = c;
450 		FST_RETURN(2,3,FST_RT);
451 	}
452 
453 	DPRINTFN(4, ("midi_fst: s=%p data=0x%02x state=%d\n",
454 		     s, c, s->state));
455 
456         switch ( s->state   | MIDI_CAT(c) ) { /* break ==> return FST_MORE */
457 
458 	case MIDI_IN_START  | MIDI_CAT_COMMON:
459 	case MIDI_IN_RUN1_1 | MIDI_CAT_COMMON:
460 	case MIDI_IN_RUN2_2 | MIDI_CAT_COMMON:
461 	case MIDI_IN_RXX2_2 | MIDI_CAT_COMMON:
462 	        s->msg[0] = c;
463 	        switch ( c ) {
464 		case 0xf0: s->state = MIDI_IN_SYX1_3; break;
465 		case 0xf1: s->state = MIDI_IN_COM0_1; break;
466 		case 0xf2: s->state = MIDI_IN_COM0_2; break;
467 		case 0xf3: s->state = MIDI_IN_COM0_1; break;
468 		case 0xf6: s->state = MIDI_IN_START;  FST_RETURN(0,1,FST_COM);
469 		case 0xf7: s->state = MIDI_IN_START;  FST_RETURN(0,0,FST_COM);
470 		default: goto protocol_violation;
471 		}
472 		break;
473 
474 	case MIDI_IN_RUN1_1 | MIDI_CAT_STATUS1:
475 		if ( c == s->msg[0] ) {
476 			s->state = MIDI_IN_RNX0_1;
477 			break;
478 		}
479 		/* FALLTHROUGH */
480 	case MIDI_IN_RUN2_2 | MIDI_CAT_STATUS1:
481 	case MIDI_IN_RXX2_2 | MIDI_CAT_STATUS1:
482 	case MIDI_IN_START  | MIDI_CAT_STATUS1:
483 	        s->state = MIDI_IN_RUN0_1;
484 	        s->msg[0] = c;
485 		break;
486 
487 	case MIDI_IN_RUN2_2 | MIDI_CAT_STATUS2:
488 	case MIDI_IN_RXX2_2 | MIDI_CAT_STATUS2:
489 		if ( c == s->msg[0] ) {
490 			s->state = MIDI_IN_RNX0_2;
491 			break;
492 		}
493 		if ( (c ^ s->msg[0]) == 0x10 && (c & 0xe0) == 0x80 ) {
494 			s->state = MIDI_IN_RXX0_2;
495 			s->msg[0] = c;
496 			break;
497 		}
498 		/* FALLTHROUGH */
499 	case MIDI_IN_RUN1_1 | MIDI_CAT_STATUS2:
500 	case MIDI_IN_START  | MIDI_CAT_STATUS2:
501 	        s->state = MIDI_IN_RUN0_2;
502 	        s->msg[0] = c;
503 		break;
504 
505         case MIDI_IN_COM0_1 | MIDI_CAT_DATA:
506 		s->state = MIDI_IN_START;
507 	        s->msg[1] = c;
508 		FST_RETURN(0,2,FST_COM);
509 
510         case MIDI_IN_COM0_2 | MIDI_CAT_DATA:
511 	        s->state = MIDI_IN_COM1_2;
512 	        s->msg[1] = c;
513 		break;
514 
515         case MIDI_IN_COM1_2 | MIDI_CAT_DATA:
516 		s->state = MIDI_IN_START;
517 	        s->msg[2] = c;
518 		FST_RETURN(0,3,FST_COM);
519 
520         case MIDI_IN_RUN0_1 | MIDI_CAT_DATA:
521 		s->state = MIDI_IN_RUN1_1;
522 	        s->msg[1] = c;
523 		FST_RETURN(0,2,FST_CHN);
524 
525         case MIDI_IN_RUN1_1 | MIDI_CAT_DATA:
526         case MIDI_IN_RNX0_1 | MIDI_CAT_DATA:
527 		s->state = MIDI_IN_RUN1_1;
528 	        s->msg[1] = c;
529 		FST_CRETURN(2);
530 
531         case MIDI_IN_RUN0_2 | MIDI_CAT_DATA:
532 	        s->state = MIDI_IN_RUN1_2;
533 	        s->msg[1] = c;
534 		break;
535 
536         case MIDI_IN_RUN1_2 | MIDI_CAT_DATA:
537 		if ( FST_CANON == form && 0 == c && (s->msg[0]&0xf0) == 0x90 ) {
538 			s->state = MIDI_IN_RXX2_2;
539 			s->msg[0] ^= 0x10;
540 			s->msg[2] = 64;
541 		} else {
542 			s->state = MIDI_IN_RUN2_2;
543 	        	s->msg[2] = c;
544 		}
545 		FST_RETURN(0,3,FST_CHN);
546 
547         case MIDI_IN_RUN2_2 | MIDI_CAT_DATA:
548 	        s->state = MIDI_IN_RNX1_2;
549 	        s->msg[1] = c;
550 		break;
551 
552         case MIDI_IN_RXX2_2 | MIDI_CAT_DATA:
553 	        s->state = MIDI_IN_RXX1_2;
554 		s->msg[0] ^= 0x10;
555 	        s->msg[1] = c;
556 		break;
557 
558         case MIDI_IN_RNX0_2 | MIDI_CAT_DATA:
559 	        s->state = MIDI_IN_RNY1_2;
560 	        s->msg[1] = c;
561 		break;
562 
563         case MIDI_IN_RXX0_2 | MIDI_CAT_DATA:
564 	        s->state = MIDI_IN_RXY1_2;
565 	        s->msg[1] = c;
566 		break;
567 
568         case MIDI_IN_RNX1_2 | MIDI_CAT_DATA:
569         case MIDI_IN_RNY1_2 | MIDI_CAT_DATA:
570 		if ( FST_CANON == form && 0 == c && (s->msg[0]&0xf0) == 0x90 ) {
571 			s->state = MIDI_IN_RXX2_2;
572 			s->msg[0] ^= 0x10;
573 			s->msg[2] = 64;
574 			FST_RETURN(0,3,FST_CHN);
575 		}
576 		s->state = MIDI_IN_RUN2_2;
577 	        s->msg[2] = c;
578 		FST_CRETURN(3);
579 
580         case MIDI_IN_RXX1_2 | MIDI_CAT_DATA:
581         case MIDI_IN_RXY1_2 | MIDI_CAT_DATA:
582 		if ( ( 0 == c && (s->msg[0]&0xf0) == 0x90)
583 		  || (64 == c && (s->msg[0]&0xf0) == 0x80
584 		      && FST_CANON != form) ) {
585 			s->state = MIDI_IN_RXX2_2;
586 			s->msg[0] ^= 0x10;
587 			s->msg[2] = 64 - c;
588 			FST_CRETURN(3);
589 		}
590 		s->state = MIDI_IN_RUN2_2;
591 	        s->msg[2] = c;
592 		FST_RETURN(0,3,FST_CHN);
593 
594         case MIDI_IN_SYX1_3 | MIDI_CAT_DATA:
595 		s->state = MIDI_IN_SYX2_3;
596 	        s->msg[1] = c;
597 		break;
598 
599         case MIDI_IN_SYX2_3 | MIDI_CAT_DATA:
600 		s->state = MIDI_IN_SYX0_3;
601 	        s->msg[2] = c;
602 		FST_RETURN(0,3,FST_SYX);
603 
604         case MIDI_IN_SYX0_3 | MIDI_CAT_DATA:
605 		s->state = MIDI_IN_SYX1_3;
606 	        s->msg[0] = c;
607 		break;
608 
609         case MIDI_IN_SYX2_3 | MIDI_CAT_COMMON:
610         case MIDI_IN_SYX2_3 | MIDI_CAT_STATUS1:
611         case MIDI_IN_SYX2_3 | MIDI_CAT_STATUS2:
612 		++ syxpos;
613 		/* FALLTHROUGH */
614         case MIDI_IN_SYX1_3 | MIDI_CAT_COMMON:
615         case MIDI_IN_SYX1_3 | MIDI_CAT_STATUS1:
616         case MIDI_IN_SYX1_3 | MIDI_CAT_STATUS2:
617 		++ syxpos;
618 		/* FALLTHROUGH */
619         case MIDI_IN_SYX0_3 | MIDI_CAT_COMMON:
620         case MIDI_IN_SYX0_3 | MIDI_CAT_STATUS1:
621         case MIDI_IN_SYX0_3 | MIDI_CAT_STATUS2:
622 		s->state = MIDI_IN_START;
623 	        if ( c == 0xf7 ) {
624 			s->msg[syxpos] = c;
625 		        FST_RETURN(0,1+syxpos,FST_SYX);
626 		}
627 		s->msg[syxpos] = 0xf7;
628 		FST_RETURN(0,1+syxpos,FST_SXP);
629 
630         default:
631 protocol_violation:
632                 DPRINTF(("midi_fst: unexpected %#02x in state %u\n",
633 		        c, s->state));
634 		switch ( s->state ) {
635 		case MIDI_IN_RUN1_1: /* can only get here by seeing an */
636 		case MIDI_IN_RUN2_2: /* INVALID System Common message */
637 		case MIDI_IN_RXX2_2:
638 		        s->state = MIDI_IN_START;
639 			/* FALLTHROUGH */
640 		case MIDI_IN_START:
641 			s->bytesDiscarded.ev_count++;
642 			return FST_ERR;
643 		case MIDI_IN_COM1_2:
644 		case MIDI_IN_RUN1_2:
645 		case MIDI_IN_RNY1_2:
646 		case MIDI_IN_RXY1_2:
647 			s->bytesDiscarded.ev_count++;
648 			/* FALLTHROUGH */
649 		case MIDI_IN_COM0_1:
650 		case MIDI_IN_RUN0_1:
651 		case MIDI_IN_RNX0_1:
652 		case MIDI_IN_COM0_2:
653 		case MIDI_IN_RUN0_2:
654 		case MIDI_IN_RNX0_2:
655 		case MIDI_IN_RXX0_2:
656 		case MIDI_IN_RNX1_2:
657 		case MIDI_IN_RXX1_2:
658 			s->bytesDiscarded.ev_count++;
659 		        s->incompleteMessages.ev_count++;
660 			break;
661 #if defined(AUDIO_DEBUG) || defined(DIAGNOSTIC)
662 		default:
663 		        printf("midi_fst: mishandled %#02x(%u) in state %u?!\n",
664 			      c, MIDI_CAT(c), s->state);
665 #endif
666 		}
667 		s->state = MIDI_IN_START;
668 		return FST_HUH;
669 	}
670 	return FST_MORE;
671 }
672 
673 void
674 midi_softintr_rd(void *cookie)
675 {
676 	struct midi_softc *sc = cookie;
677 	struct proc *p;
678 
679 	if (sc->async != NULL) {
680 		mutex_enter(&proclist_mutex);
681 		if ((p = sc->async) != NULL)
682 			psignal(p, SIGIO);
683 		mutex_exit(&proclist_mutex);
684 	}
685 	midi_wakeup(&sc->rchan);
686 	selnotify(&sc->rsel, 0); /* filter will spin if locked */
687 }
688 
689 void
690 midi_softintr_wr(void *cookie)
691 {
692 	struct midi_softc *sc = cookie;
693 	struct proc *p;
694 
695 	if (sc->async != NULL) {
696 		mutex_enter(&proclist_mutex);
697 		if ((p = sc->async) != NULL)
698 			psignal(p, SIGIO);
699 		mutex_exit(&proclist_mutex);
700 	}
701 	midi_wakeup(&sc->wchan);
702 	selnotify(&sc->wsel, 0); /* filter will spin if locked */
703 }
704 
705 void
706 midi_in(void *addr, int data)
707 {
708 	struct midi_softc *sc = addr;
709 	struct midi_buffer *mb = &sc->inbuf;
710 	int i;
711 	int count;
712 	enum fst_ret got;
713 	int s; /* hw may have various spls so impose our own */
714 	MIDI_BUF_DECLARE(idx);
715 	MIDI_BUF_DECLARE(buf);
716 
717 	if (!sc->isopen)
718 		return;
719 
720 	if (!(sc->flags & FREAD))
721 		return;		/* discard data if not reading */
722 
723 sxp_again:
724 	do
725 		got = midi_fst(&sc->rcv, data, FST_CANON);
726 	while ( got == FST_HUH );
727 
728 	switch ( got ) {
729 	case FST_MORE:
730 	case FST_ERR:
731 		return;
732 	case FST_CHN:
733 	case FST_COM:
734 	case FST_RT:
735 #if NSEQUENCER > 0
736 		if (sc->seqopen) {
737 			extern void midiseq_in(struct midi_dev *,u_char *,int);
738 			count = sc->rcv.end - sc->rcv.pos;
739 			midiseq_in(sc->seq_md, sc->rcv.pos, count);
740 			return;
741 		}
742 #endif
743         	/*
744 		 * Pass Active Sense to the sequencer if it's open, but not to
745 		 * a raw reader. (Really should do something intelligent with
746 		 * it then, though....)
747 		 */
748 		if ( got == FST_RT && MIDI_ACK == sc->rcv.pos[0] ) {
749 			if ( !sc->rcv_expect_asense ) {
750 				sc->rcv_expect_asense = 1;
751 				callout_schedule(&sc->rcv_asense_co,
752 				                 MIDI_RCV_ASENSE_PERIOD);
753 			}
754 			sc->rcv_quiescent = 0;
755 			sc->rcv_eof = 0;
756 			return;
757 		}
758 		/* FALLTHROUGH */
759 	/*
760 	 * Ultimately SysEx msgs should be offered to the sequencer also; the
761 	 * sequencer API addresses them - but maybe our sequencer can't handle
762 	 * them yet, so offer only to raw reader. (Which means, ultimately,
763 	 * discard them if the sequencer's open, as it's not doing reads!)
764 	 * -> When SysEx support is added to the sequencer, be sure to handle
765 	 *    FST_SXP there too.
766 	 */
767 	case FST_SYX:
768 	case FST_SXP:
769 		count = sc->rcv.end - sc->rcv.pos;
770 		MIDI_IN_LOCK(sc,s);
771 		sc->rcv_quiescent = 0;
772 		sc->rcv_eof = 0;
773 		if ( 0 == count ) {
774 			MIDI_IN_UNLOCK(sc,s);
775 			break;
776 		}
777 		MIDI_BUF_PRODUCER_INIT(mb,idx);
778 		MIDI_BUF_PRODUCER_INIT(mb,buf);
779 		if (count > buf_lim - buf_cur
780 		     || 1 > idx_lim - idx_cur) {
781 			sc->rcv.bytesDiscarded.ev_count += count;
782 			MIDI_IN_UNLOCK(sc,s);
783 			DPRINTF(("midi_in: buffer full, discard data=0x%02x\n",
784 				 sc->rcv.pos[0]));
785 			return;
786 		}
787 		for (i = 0; i < count; i++) {
788 			*buf_cur++ = sc->rcv.pos[i];
789 			MIDI_BUF_WRAP(buf);
790 		}
791 		*idx_cur++ = PACK_MB_IDX(got,count);
792 		MIDI_BUF_WRAP(idx);
793 		MIDI_BUF_PRODUCER_WBACK(mb,buf);
794 		MIDI_BUF_PRODUCER_WBACK(mb,idx);
795 		MIDI_IN_UNLOCK(sc,s);
796 		softint_schedule(sc->sih_rd);
797 		break;
798 	default: /* don't #ifdef this away, gcc will say FST_HUH not handled */
799 		printf("midi_in: midi_fst returned %d?!\n", got);
800 	}
801 	if ( FST_SXP == got )
802 		goto sxp_again;
803 }
804 
805 void
806 midi_out(void *addr)
807 {
808 	struct midi_softc *sc = addr;
809 
810 	if (!sc->isopen)
811 		return;
812 	DPRINTFN(8, ("midi_out: %p\n", sc));
813 	midi_intr_out(sc);
814 }
815 
816 int
817 midiopen(dev_t dev, int flags, int ifmt, struct lwp *l)
818 {
819 	struct midi_softc *sc;
820 	const struct midi_hw_if *hw;
821 	int error;
822 
823 	sc = device_lookup(&midi_cd, MIDIUNIT(dev));
824 	if (sc == NULL)
825 		return (ENXIO);
826 	if (sc->dying)
827 		return (EIO);
828 
829 	DPRINTFN(3,("midiopen %p\n", sc));
830 
831 	hw = sc->hw_if;
832 	if (!hw)
833 		return ENXIO;
834 	if (sc->isopen)
835 		return EBUSY;
836 
837 	/* put both state machines into known states */
838 	sc->rcv.state = MIDI_IN_START;
839 	sc->rcv.pos = sc->rcv.msg;
840 	sc->rcv.end = sc->rcv.msg;
841 	sc->xmt.state = MIDI_IN_START;
842 	sc->xmt.pos = sc->xmt.msg;
843 	sc->xmt.end = sc->xmt.msg;
844 
845 	/* copy error counters so an ioctl (TBA) can give since-open stats */
846 	sc->rcv.atOpen.bytesDiscarded  = sc->rcv.bytesDiscarded.ev_count;
847 	sc->rcv.atQuery.bytesDiscarded = sc->rcv.bytesDiscarded.ev_count;
848 
849 	sc->xmt.atOpen.bytesDiscarded  = sc->xmt.bytesDiscarded.ev_count;
850 	sc->xmt.atQuery.bytesDiscarded = sc->xmt.bytesDiscarded.ev_count;
851 
852 	/* and the buffers */
853 	midi_initbuf(&sc->outbuf);
854 	midi_initbuf(&sc->inbuf);
855 
856 	/* and the receive flags */
857 	sc->rcv_expect_asense = 0;
858 	sc->rcv_quiescent = 0;
859 	sc->rcv_eof = 0;
860 
861 	error = hw->open(sc->hw_hdl, flags, midi_in, midi_out, sc);
862 	if (error)
863 		return error;
864 	sc->isopen++;
865 	sc->flags = flags;
866 	sc->rchan = 0;
867 	sc->wchan = 0;
868 	sc->pbus = 0;
869 	sc->async = 0;
870 
871 #ifdef MIDI_SAVE
872 	if (midicnt != 0) {
873 		midisave.cnt = midicnt;
874 		midicnt = 0;
875 	}
876 #endif
877 
878 	return 0;
879 }
880 
881 int
882 midiclose(dev_t dev, int flags, int ifmt,
883     struct lwp *l)
884 {
885 	int unit = MIDIUNIT(dev);
886 	struct midi_softc *sc = midi_cd.cd_devs[unit];
887 	const struct midi_hw_if *hw = sc->hw_if;
888 	int s, error;
889 
890 	DPRINTFN(3,("midiclose %p\n", sc));
891 
892 	/* midi_start_output(sc); anything buffered => pbus already set! */
893 	error = 0;
894 	MIDI_OUT_LOCK(sc,s);
895 	while (sc->pbus) {
896 		DPRINTFN(8,("midiclose sleep ...\n"));
897 		error =
898 		midi_sleep_timo(&sc->wchan, "mid_dr", 30*hz, &sc->out_lock);
899 	}
900 	sc->isopen = 0;
901 	MIDI_OUT_UNLOCK(sc,s);
902 	callout_stop(&sc->xmt_asense_co); /* xxx fix this - sleep? */
903 	callout_stop(&sc->rcv_asense_co);
904 	hw->close(sc->hw_hdl);
905 #if NSEQUENCER > 0
906 	sc->seqopen = 0;
907 	sc->seq_md = 0;
908 #endif
909 	return 0;
910 }
911 
912 int
913 midiread(dev_t dev, struct uio *uio, int ioflag)
914 {
915 	int unit = MIDIUNIT(dev);
916 	struct midi_softc *sc = midi_cd.cd_devs[unit];
917 	struct midi_buffer *mb = &sc->inbuf;
918 	int error;
919 	int s;
920 	MIDI_BUF_DECLARE(idx);
921 	MIDI_BUF_DECLARE(buf);
922 	int appetite;
923 	int first = 1;
924 
925 	DPRINTFN(6,("midiread: %p, count=%lu\n", sc,
926 		 (unsigned long)uio->uio_resid));
927 
928 	if (sc->dying)
929 		return EIO;
930         if ( !(sc->props & MIDI_PROP_CAN_INPUT) )
931 	        return ENXIO;
932 
933 	MIDI_IN_LOCK(sc,s);
934 	MIDI_BUF_CONSUMER_INIT(mb,idx);
935 	MIDI_BUF_CONSUMER_INIT(mb,buf);
936 	MIDI_IN_UNLOCK(sc,s);
937 
938 	error = 0;
939 	for ( ;; ) {
940 		/*
941 		 * If the used portion of idx wraps around the end, just take
942 		 * the first part on this iteration, and we'll get the rest on
943 		 * the next.
944 		 */
945 		if ( idx_lim > idx_end )
946 			idx_lim = idx_end;
947 		/*
948 		 * Count bytes through the last complete message that will
949 		 * fit in the requested read.
950 		 */
951 		for (appetite = uio->uio_resid; idx_cur < idx_lim; ++idx_cur) {
952 			if ( appetite < MB_IDX_LEN(*idx_cur) )
953 				break;
954 			appetite -= MB_IDX_LEN(*idx_cur);
955 		}
956 		appetite = uio->uio_resid - appetite;
957 		/*
958 		 * Only if the read is too small to hold even the first
959 		 * complete message will we return a partial one (updating idx
960 		 * to reflect the remaining length of the message).
961 		 */
962 		if ( appetite == 0 && idx_cur < idx_lim ) {
963 			if ( !first )
964 				goto unlocked_exit; /* idx_cur not advanced */
965 			appetite = uio->uio_resid;
966 			*idx_cur = PACK_MB_IDX(MB_IDX_CAT(*idx_cur),
967 					       MB_IDX_LEN(*idx_cur) - appetite);
968 		}
969 		KASSERT(buf_cur + appetite <= buf_lim);
970 
971 		/* move the bytes */
972 		if ( appetite > 0 ) {
973 			first = 0;  /* we know we won't return empty-handed */
974 			/* do two uiomoves if data wrap around end of buf */
975 			if ( buf_cur + appetite > buf_end ) {
976 				DPRINTFN(8,
977 					("midiread: uiomove cc=%td (prewrap)\n",
978 					buf_end - buf_cur));
979 				error = uiomove(buf_cur, buf_end-buf_cur, uio);
980 				if ( error )
981 					goto unlocked_exit;
982 				appetite -= buf_end - buf_cur;
983 				buf_cur = mb->buf;
984 			}
985 			DPRINTFN(8, ("midiread: uiomove cc=%d\n", appetite));
986 			error = uiomove(buf_cur, appetite, uio);
987 			if ( error )
988 				goto unlocked_exit;
989 			buf_cur += appetite;
990 		}
991 
992 		MIDI_BUF_WRAP(idx);
993 		MIDI_BUF_WRAP(buf);
994 
995 		MIDI_IN_LOCK(sc,s);
996 		MIDI_BUF_CONSUMER_WBACK(mb,idx);
997 		MIDI_BUF_CONSUMER_WBACK(mb,buf);
998 		if ( 0 == uio->uio_resid ) /* if read satisfied, we're done */
999 			break;
1000 		MIDI_BUF_CONSUMER_REFRESH(mb,idx);
1001 		if ( idx_cur == idx_lim ) { /* need to wait for data? */
1002 			if ( !first || sc->rcv_eof ) /* never block reader if */
1003 				break;            /* any data already in hand */
1004 			if (ioflag & IO_NDELAY) {
1005 				error = EWOULDBLOCK;
1006 				break;
1007 			}
1008 			error = midi_sleep(&sc->rchan, "mid rd", &sc->in_lock);
1009 			if ( error )
1010 				break;
1011 			MIDI_BUF_CONSUMER_REFRESH(mb,idx); /* what'd we get? */
1012 		}
1013 		MIDI_BUF_CONSUMER_REFRESH(mb,buf);
1014 		MIDI_IN_UNLOCK(sc,s);
1015 		if ( sc->dying )
1016 			return EIO;
1017 	}
1018 	MIDI_IN_UNLOCK(sc,s);
1019 
1020 unlocked_exit:
1021 	return error;
1022 }
1023 
1024 void
1025 midi_rcv_asense(void *arg)
1026 {
1027 	struct midi_softc *sc = arg;
1028 	int s;
1029 
1030 	if ( sc->dying || !sc->isopen )
1031 		return;
1032 
1033 	if ( sc->rcv_quiescent ) {
1034 		MIDI_IN_LOCK(sc,s);
1035 		sc->rcv_eof = 1;
1036 		sc->rcv_quiescent = 0;
1037 		sc->rcv_expect_asense = 0;
1038 		MIDI_IN_UNLOCK(sc,s);
1039 		softint_schedule(sc->sih_rd);
1040 		return;
1041 	}
1042 
1043 	sc->rcv_quiescent = 1;
1044 	callout_schedule(&sc->rcv_asense_co, MIDI_RCV_ASENSE_PERIOD);
1045 }
1046 
1047 void
1048 midi_xmt_asense(void *arg)
1049 {
1050 	struct midi_softc *sc = arg;
1051 	int s;
1052 	int error;
1053 	int armed;
1054 
1055 	if ( sc->dying || !sc->isopen )
1056 		return;
1057 
1058 	MIDI_OUT_LOCK(sc,s);
1059 	if ( sc->pbus || sc->dying || !sc->isopen ) {
1060 		MIDI_OUT_UNLOCK(sc,s);
1061 		return;
1062 	}
1063 	sc->pbus = 1;
1064 	DPRINTFN(8,("midi_xmt_asense: %p\n", sc));
1065 
1066 	if ( sc->props & MIDI_PROP_OUT_INTR ) {
1067 		error = sc->hw_if->output(sc->hw_hdl, MIDI_ACK);
1068 		armed = (error == 0);
1069 	} else { /* polled output, do with interrupts unmasked */
1070 		MIDI_OUT_UNLOCK(sc,s);
1071 		/* running from softclock, so top half won't sneak in here */
1072 		error = sc->hw_if->output(sc->hw_hdl, MIDI_ACK);
1073 		MIDI_OUT_LOCK(sc,s);
1074 		armed = 0;
1075 	}
1076 
1077 	if ( !armed ) {
1078 		sc->pbus = 0;
1079 		callout_schedule(&sc->xmt_asense_co, MIDI_XMT_ASENSE_PERIOD);
1080 	}
1081 
1082 	MIDI_OUT_UNLOCK(sc,s);
1083 }
1084 
1085 /*
1086  * The way this function was hacked up to plug into poll_out and intr_out
1087  * after they were written won't win it any beauty contests, but it'll work
1088  * (code in haste, refactor at leisure). This may be called with the lock
1089  * (by intr_out) or without the lock (by poll_out) so it only does what could
1090  * be safe either way.
1091  */
1092 int midi_msg_out(struct midi_softc *sc,
1093                  u_char **idx, u_char **idxl, u_char **buf, u_char **bufl) {
1094 	MIDI_BUF_DECLARE(idx);
1095 	MIDI_BUF_DECLARE(buf);
1096 	MIDI_BUF_EXTENT_INIT(&sc->outbuf,idx);
1097 	MIDI_BUF_EXTENT_INIT(&sc->outbuf,buf);
1098 	int length;
1099 	int error;
1100 	u_char contig[3];
1101 	u_char *cp;
1102 	u_char *ep;
1103 
1104 	idx_cur = *idx;
1105 	idx_lim = *idxl;
1106 	buf_cur = *buf;
1107 	buf_lim = *bufl;
1108 
1109 	length = MB_IDX_LEN(*idx_cur);
1110 
1111 	for ( cp = contig, ep = cp + length; cp < ep; ) {
1112 		*cp++ = *buf_cur++;
1113 		MIDI_BUF_WRAP(buf);
1114 	}
1115 	cp = contig;
1116 
1117 	switch ( MB_IDX_CAT(*idx_cur) ) {
1118 	case FST_CHV: /* chnmsg to be compressed (for device that wants it) */
1119 		++ cp;
1120 		-- length;
1121 		/* FALLTHROUGH */
1122 	case FST_CHN:
1123 		error = sc->hw_if_ext->channel(sc->hw_hdl,
1124 		                               MIDI_GET_STATUS(contig[0]),
1125 					       MIDI_GET_CHAN(contig[0]),
1126 					       cp, length);
1127 		break;
1128 	case FST_COM:
1129 		error = sc->hw_if_ext->common(sc->hw_hdl,
1130 		                              MIDI_GET_STATUS(contig[0]),
1131 					      cp, length);
1132 		break;
1133 	case FST_SYX:
1134 	case FST_SXP:
1135 		error = sc->hw_if_ext->sysex(sc->hw_hdl,
1136 					     cp, length);
1137 		break;
1138 	case FST_RT:
1139 		error = sc->hw_if->output(sc->hw_hdl, *cp);
1140 		break;
1141 	default:
1142 		error = EIO;
1143 	}
1144 
1145 	if ( !error ) {
1146 		++ idx_cur;
1147 		MIDI_BUF_WRAP(idx);
1148 		*idx  = idx_cur;
1149 		*idxl = idx_lim;
1150 		*buf  = buf_cur;
1151 		*bufl = buf_lim;
1152 	}
1153 
1154 	return error;
1155 }
1156 
1157 /*
1158  * midi_poll_out is intended for the midi hw (the vast majority of MIDI UARTs
1159  * on sound cards, apparently) that _do not have transmit-ready interrupts_.
1160  * Every call to hw_if->output for one of these may busy-wait to output the
1161  * byte; at the standard midi data rate that'll be 320us per byte. The
1162  * technique of writing only MIDI_MAX_WRITE bytes in a row and then waiting
1163  * for MIDI_WAIT does not reduce the total time spent busy-waiting, and it
1164  * adds arbitrary delays in transmission (and, since MIDI_WAIT is roughly the
1165  * same as the time to send MIDI_MAX_WRITE bytes, it effectively halves the
1166  * data rate). Here, a somewhat bolder approach is taken. Since midi traffic
1167  * is bursty but time-sensitive--most of the time there will be none at all,
1168  * but when there is it should go out ASAP--the strategy is to just get it
1169  * over with, and empty the buffer in one go. The effect this can have on
1170  * the rest of the system will be limited by the size of the buffer and the
1171  * sparseness of the traffic. But some precautions are in order. Interrupts
1172  * should all be unmasked when this is called, and midiwrite should not fill
1173  * the buffer more than once (when MIDI_PROP_CAN_INTR is false) without a
1174  * yield() so some other process can get scheduled. If the write is nonblocking,
1175  * midiwrite should return a short count rather than yield.
1176  *
1177  * Someday when there is fine-grained MP support, this should be reworked to
1178  * run in a callout so the writing process really could proceed concurrently.
1179  * But obviously where performance is a concern, interrupt-driven hardware
1180  * such as USB midi or (apparently) clcs will always be preferable. And it
1181  * seems (kern/32651) that many of the devices currently working in poll mode
1182  * may really have tx interrupt capability and want only implementation; that
1183  * ought to happen.
1184  */
1185 int
1186 midi_poll_out(struct midi_softc *sc)
1187 {
1188 	struct midi_buffer *mb = &sc->outbuf;
1189 	int error;
1190 	int msglen;
1191 	int s;
1192 	MIDI_BUF_DECLARE(idx);
1193 	MIDI_BUF_DECLARE(buf);
1194 
1195 	error = 0;
1196 
1197 	MIDI_OUT_LOCK(sc,s);
1198 	MIDI_BUF_CONSUMER_INIT(mb,idx);
1199 	MIDI_BUF_CONSUMER_INIT(mb,buf);
1200 	MIDI_OUT_UNLOCK(sc,s);
1201 
1202 	for ( ;; ) {
1203 		while ( idx_cur != idx_lim ) {
1204 			if ( sc->hw_if_ext ) {
1205 				error = midi_msg_out(sc, &idx_cur, &idx_lim,
1206 				                         &buf_cur, &buf_lim);
1207 				if ( error )
1208 					goto ioerror;
1209 				continue;
1210 			}
1211 			/* or, lacking hw_if_ext ... */
1212 			msglen = MB_IDX_LEN(*idx_cur);
1213 			DPRINTFN(7,("midi_poll_out: %p <- %#02x\n",
1214 				   sc->hw_hdl, *buf_cur));
1215 			error = sc->hw_if->output(sc->hw_hdl, *buf_cur);
1216 			if ( error )
1217 				goto ioerror;
1218 			++ buf_cur;
1219 			MIDI_BUF_WRAP(buf);
1220 			-- msglen;
1221 			if ( msglen )
1222 				*idx_cur = PACK_MB_IDX(MB_IDX_CAT(*idx_cur),
1223 				                       msglen);
1224 			else {
1225 				++ idx_cur;
1226 				MIDI_BUF_WRAP(idx);
1227 			}
1228 		}
1229 		KASSERT(buf_cur == buf_lim);
1230 		MIDI_OUT_LOCK(sc,s);
1231 		MIDI_BUF_CONSUMER_WBACK(mb,idx);
1232 		MIDI_BUF_CONSUMER_WBACK(mb,buf);
1233 		MIDI_BUF_CONSUMER_REFRESH(mb,idx); /* any more to transmit? */
1234 		MIDI_BUF_CONSUMER_REFRESH(mb,buf);
1235 		if ( idx_lim == idx_cur )
1236 			break; /* still holding lock */
1237 		MIDI_OUT_UNLOCK(sc,s);
1238 	}
1239 	goto disarm; /* lock held */
1240 
1241 ioerror:
1242 #if defined(AUDIO_DEBUG) || defined(DIAGNOSTIC)
1243 	printf("%s: midi_poll_output error %d\n",
1244 	      sc->dev.dv_xname, error);
1245 #endif
1246 	MIDI_OUT_LOCK(sc,s);
1247 	MIDI_BUF_CONSUMER_WBACK(mb,idx);
1248 	MIDI_BUF_CONSUMER_WBACK(mb,buf);
1249 
1250 disarm:
1251 	sc->pbus = 0;
1252 	callout_schedule(&sc->xmt_asense_co, MIDI_XMT_ASENSE_PERIOD);
1253 	MIDI_OUT_UNLOCK(sc,s);
1254 	return error;
1255 }
1256 
1257 /*
1258  * The interrupt flavor acquires spl and lock once and releases at the end,
1259  * as it expects to write only one byte or message. The interface convention
1260  * is that if hw_if->output returns 0, it has initiated transmission and the
1261  * completion interrupt WILL be forthcoming; if it has not returned 0, NO
1262  * interrupt will be forthcoming, and if it returns EINPROGRESS it wants
1263  * another byte right away.
1264  */
1265 int
1266 midi_intr_out(struct midi_softc *sc)
1267 {
1268 	struct midi_buffer *mb = &sc->outbuf;
1269 	int error;
1270 	int msglen;
1271 	int s;
1272 	MIDI_BUF_DECLARE(idx);
1273 	MIDI_BUF_DECLARE(buf);
1274 	int armed = 0;
1275 
1276 	error = 0;
1277 
1278 	MIDI_OUT_LOCK(sc,s);
1279 	MIDI_BUF_CONSUMER_INIT(mb,idx);
1280 	MIDI_BUF_CONSUMER_INIT(mb,buf);
1281 
1282 	while ( idx_cur != idx_lim ) {
1283 		if ( sc->hw_if_ext ) {
1284 			error = midi_msg_out(sc, &idx_cur, &idx_lim,
1285 				                 &buf_cur, &buf_lim);
1286 			if ( !error ) /* no EINPROGRESS from extended hw_if */
1287 				armed = 1;
1288 			break;
1289 		}
1290 		/* or, lacking hw_if_ext ... */
1291 		msglen = MB_IDX_LEN(*idx_cur);
1292 		error = sc->hw_if->output(sc->hw_hdl, *buf_cur);
1293 		if ( error  &&  error != EINPROGRESS )
1294 			break;
1295 		++ buf_cur;
1296 		MIDI_BUF_WRAP(buf);
1297 		-- msglen;
1298 		if ( msglen )
1299 			*idx_cur = PACK_MB_IDX(MB_IDX_CAT(*idx_cur),msglen);
1300 		else {
1301 			++ idx_cur;
1302 			MIDI_BUF_WRAP(idx);
1303 		}
1304 		if ( !error ) {
1305 			armed = 1;
1306 			break;
1307 		}
1308 	}
1309 	MIDI_BUF_CONSUMER_WBACK(mb,idx);
1310 	MIDI_BUF_CONSUMER_WBACK(mb,buf);
1311 	if ( !armed ) {
1312 		sc->pbus = 0;
1313 		callout_schedule(&sc->xmt_asense_co, MIDI_XMT_ASENSE_PERIOD);
1314 	}
1315 	MIDI_OUT_UNLOCK(sc,s);
1316 	softint_schedule(sc->sih_wr);
1317 
1318 #if defined(AUDIO_DEBUG) || defined(DIAGNOSTIC)
1319 	if ( error )
1320 		printf("%s: midi_intr_output error %d\n",
1321 	               sc->dev.dv_xname, error);
1322 #endif
1323 	return error;
1324 }
1325 
1326 int
1327 midi_start_output(struct midi_softc *sc)
1328 {
1329 	if (sc->dying)
1330 		return EIO;
1331 
1332 	if ( sc->props & MIDI_PROP_OUT_INTR )
1333 		return midi_intr_out(sc);
1334 	return midi_poll_out(sc);
1335 }
1336 
1337 static int
1338 real_writebytes(struct midi_softc *sc, u_char *ibuf, int cc)
1339 {
1340 	u_char *iend = ibuf + cc;
1341 	struct midi_buffer *mb = &sc->outbuf;
1342 	int arming = 0;
1343 	int count;
1344 	int s;
1345 	int got;
1346 	enum fst_form form;
1347 	MIDI_BUF_DECLARE(idx);
1348 	MIDI_BUF_DECLARE(buf);
1349 
1350 	/*
1351 	 * If the hardware uses the extended hw_if, pass it canonicalized
1352 	 * messages (or compressed ones if it specifically requests, using
1353 	 * VCOMP form so the bottom half can still pass the op and chan along);
1354 	 * if it does not, send it compressed messages (using COMPR form as
1355 	 * there is no need to preserve the status for the bottom half).
1356 	 */
1357 	if ( NULL == sc->hw_if_ext )
1358 		form = FST_COMPR;
1359 	else if ( sc->hw_if_ext->compress )
1360 		form = FST_VCOMP;
1361 	else
1362 		form = FST_CANON;
1363 
1364 	MIDI_OUT_LOCK(sc,s);
1365 	MIDI_BUF_PRODUCER_INIT(mb,idx);
1366 	MIDI_BUF_PRODUCER_INIT(mb,buf);
1367 	MIDI_OUT_UNLOCK(sc,s);
1368 
1369 	if (sc->dying)
1370 		return EIO;
1371 
1372 	while ( ibuf < iend ) {
1373 		got = midi_fst(&sc->xmt, *ibuf, form);
1374 		++ ibuf;
1375 		switch ( got ) {
1376 		case FST_MORE:
1377 			continue;
1378 		case FST_ERR:
1379 		case FST_HUH:
1380 			return EPROTO;
1381 		case FST_CHN:
1382 		case FST_CHV: /* only occurs in VCOMP form */
1383 		case FST_COM:
1384 		case FST_RT:
1385 		case FST_SYX:
1386 		case FST_SXP:
1387 			break; /* go add to buffer */
1388 #if defined(AUDIO_DEBUG) || defined(DIAGNOSTIC)
1389 		default:
1390 			printf("midi_wr: midi_fst returned %d?!\n", got);
1391 #endif
1392 		}
1393 		count = sc->xmt.end - sc->xmt.pos;
1394 		if ( 0 == count ) /* can happen with stray 0xf7; see midi_fst */
1395 			continue;
1396 		/*
1397 		 * return EWOULDBLOCK if the data passed will not fit in
1398 		 * the buffer; the caller should have taken steps to avoid that.
1399 		 * If got==FST_SXP we lose the new status byte, but we're losing
1400 		 * anyway, so c'est la vie.
1401 		 */
1402 		if ( idx_cur == idx_lim || count > buf_lim - buf_cur ) {
1403 			MIDI_OUT_LOCK(sc,s);
1404 			MIDI_BUF_PRODUCER_REFRESH(mb,idx); /* get the most */
1405 			MIDI_BUF_PRODUCER_REFRESH(mb,buf); /*  current facts */
1406 			MIDI_OUT_UNLOCK(sc,s);
1407 			if ( idx_cur == idx_lim || count > buf_lim - buf_cur )
1408 				return EWOULDBLOCK; /* caller's problem */
1409 		}
1410 		*idx_cur++ = PACK_MB_IDX(got,count);
1411 		MIDI_BUF_WRAP(idx);
1412 		while ( count ) {
1413 			*buf_cur++ = *(sc->xmt.pos)++;
1414 			MIDI_BUF_WRAP(buf);
1415 			-- count;
1416 		}
1417 		if ( FST_SXP == got )
1418 			-- ibuf; /* again with same status byte */
1419 	}
1420 	MIDI_OUT_LOCK(sc,s);
1421 	MIDI_BUF_PRODUCER_WBACK(mb,buf);
1422 	MIDI_BUF_PRODUCER_WBACK(mb,idx);
1423 	/*
1424 	 * If the output transfer is not already busy, and there is a message
1425 	 * buffered, mark it busy, stop the Active Sense callout (what if we're
1426 	 * too late and it's expired already? No big deal, an extra Active Sense
1427 	 * never hurt anybody) and start the output transfer once we're out of
1428 	 * the critical section (pbus==1 will stop anyone else doing the same).
1429 	 */
1430 	MIDI_BUF_CONSUMER_INIT(mb,idx); /* check what consumer's got to read */
1431 	if ( !sc->pbus && idx_cur < idx_lim ) {
1432 		sc->pbus = 1;
1433 		callout_stop(&sc->xmt_asense_co);
1434 		arming = 1;
1435 	}
1436 	MIDI_OUT_UNLOCK(sc,s);
1437 	return arming ? midi_start_output(sc) : 0;
1438 }
1439 
1440 int
1441 midiwrite(dev_t dev, struct uio *uio, int ioflag)
1442 {
1443 	int unit = MIDIUNIT(dev);
1444 	struct midi_softc *sc = midi_cd.cd_devs[unit];
1445 	struct midi_buffer *mb = &sc->outbuf;
1446 	int error;
1447 	u_char inp[256];
1448 	int s;
1449 	MIDI_BUF_DECLARE(idx);
1450 	MIDI_BUF_DECLARE(buf);
1451 	size_t idxspace;
1452 	size_t bufspace;
1453 	size_t xfrcount;
1454 	int pollout = 0;
1455 
1456 	DPRINTFN(6, ("midiwrite: %p, unit=%d, count=%lu\n", sc, unit,
1457 		     (unsigned long)uio->uio_resid));
1458 
1459 	if (sc->dying)
1460 		return EIO;
1461 
1462 	error = 0;
1463 	while (uio->uio_resid > 0 && !error) {
1464 
1465 		/*
1466 		 * block if necessary for the minimum buffer space to guarantee
1467 		 * we can write something.
1468 		 */
1469 		MIDI_OUT_LOCK(sc,s);
1470 		MIDI_BUF_PRODUCER_INIT(mb,idx); /* init can't go above loop; */
1471 		MIDI_BUF_PRODUCER_INIT(mb,buf); /* real_writebytes moves cur */
1472 		for ( ;; ) {
1473 			idxspace = MIDI_BUF_PRODUCER_REFRESH(mb,idx) - idx_cur;
1474 			bufspace = MIDI_BUF_PRODUCER_REFRESH(mb,buf) - buf_cur;
1475 			if ( idxspace >= 1  &&  bufspace >= 3  && !pollout )
1476 				break;
1477 			DPRINTFN(8,("midi_write: sleep idx=%zd buf=%zd\n",
1478 				 idxspace, bufspace));
1479 			if (ioflag & IO_NDELAY) {
1480 				error = EWOULDBLOCK;
1481 				/*
1482 				 * If some amount has already been transferred,
1483 				 * the common syscall code will automagically
1484 				 * convert this to success with a short count.
1485 				 */
1486 				goto locked_exit;
1487 			}
1488 			if ( pollout ) {
1489 				preempt(); /* see midi_poll_output */
1490 				pollout = 0;
1491 			} else
1492 				error = midi_sleep(&sc->wchan, "mid wr",
1493 				                   &sc->out_lock);
1494 			if (error)
1495 				/*
1496 				 * Similarly, the common code will handle
1497 				 * EINTR and ERESTART properly here, changing to
1498 				 * a short count if something transferred.
1499 				 */
1500 				goto locked_exit;
1501 		}
1502 		MIDI_OUT_UNLOCK(sc,s);
1503 
1504 		/*
1505 		 * The number of bytes we can safely extract from the uio
1506 		 * depends on the available idx and buf space. Worst case,
1507 		 * every byte is a message so 1 idx is required per byte.
1508 		 * Worst case, the first byte completes a 3-byte msg in prior
1509 		 * state, and every subsequent byte is a Program Change or
1510 		 * Channel Pressure msg with running status and expands to 2
1511 		 * bytes, so the buf space reqd is 3+2(n-1) or 2n+1. So limit
1512 		 * the transfer to the min of idxspace and (bufspace-1)>>1.
1513 		 */
1514 		xfrcount = (bufspace - 1) >> 1;
1515 		if ( xfrcount > idxspace )
1516 			xfrcount = idxspace;
1517 		if ( xfrcount > sizeof inp )
1518 			xfrcount = sizeof inp;
1519 		if ( xfrcount > uio->uio_resid )
1520 			xfrcount = uio->uio_resid;
1521 
1522 		error = uiomove(inp, xfrcount, uio);
1523 #ifdef MIDI_DEBUG
1524 		if (error)
1525 		        printf("midi_write:(1) uiomove failed %d; "
1526 			       "xfrcount=%d inp=%p\n",
1527 			       error, xfrcount, inp);
1528 #endif
1529 		if ( error )
1530 			break;
1531 
1532 		/*
1533 		 * The number of bytes we extracted being calculated to
1534 		 * definitely fit in the buffer even with canonicalization,
1535 		 * there is no excuse for real_writebytes to return EWOULDBLOCK.
1536 		 */
1537 		error = real_writebytes(sc, inp, xfrcount);
1538 		KASSERT(error != EWOULDBLOCK);
1539 
1540 		if ( error )
1541 			break;
1542 		/*
1543 		 * If this is a polling device and we just sent a buffer, let's
1544 		 * not send another without giving some other process a chance.
1545 		 */
1546 		if ( ! (sc->props & MIDI_PROP_OUT_INTR) )
1547 			pollout = 1;
1548 		DPRINTFN(8,("midiwrite: uio_resid now %zu, props=%d\n",
1549                         uio->uio_resid, sc->props));
1550 	}
1551 	return error;
1552 
1553 locked_exit:
1554 	MIDI_OUT_UNLOCK(sc,s);
1555 	return error;
1556 }
1557 
1558 /*
1559  * This write routine is only called from sequencer code and expects
1560  * a write that is smaller than the MIDI buffer.
1561  */
1562 int
1563 midi_writebytes(int unit, u_char *bf, int cc)
1564 {
1565 	struct midi_softc *sc = midi_cd.cd_devs[unit];
1566 
1567 	DPRINTFN(7, ("midi_writebytes: %p, unit=%d, cc=%d %#02x %#02x %#02x\n",
1568                     sc, unit, cc, bf[0], bf[1], bf[2]));
1569 	return real_writebytes(sc, bf, cc);
1570 }
1571 
1572 int
1573 midiioctl(dev_t dev, u_long cmd, void *addr, int flag, struct lwp *l)
1574 {
1575 	int unit = MIDIUNIT(dev);
1576 	struct midi_softc *sc = midi_cd.cd_devs[unit];
1577 	const struct midi_hw_if *hw = sc->hw_if;
1578 	int error;
1579 	int s;
1580 	MIDI_BUF_DECLARE(buf);
1581 
1582 	DPRINTFN(5,("midiioctl: %p cmd=0x%08lx\n", sc, cmd));
1583 
1584 	if (sc->dying)
1585 		return EIO;
1586 
1587 	error = 0;
1588 	switch (cmd) {
1589 	case FIONBIO:
1590 		/* All handled in the upper FS layer. */
1591 		break;
1592 
1593 	case FIONREAD:
1594 		/*
1595 		 * This code relies on the current implementation of midi_in
1596 		 * always updating buf and idx together in a critical section,
1597 		 * so buf always ends at a message boundary. Document this
1598 		 * ioctl as always returning a value such that the last message
1599 		 * included is complete (SysEx the only exception), and then
1600 		 * make sure the implementation doesn't regress.  NB that
1601 		 * means if this ioctl returns n and the proc then issues a
1602 		 * read of n, n bytes will be read, but if the proc issues a
1603 		 * read of m < n, fewer than m bytes may be read to ensure the
1604 		 * read ends at a message boundary.
1605 		 */
1606 		MIDI_IN_LOCK(sc,s);
1607 		MIDI_BUF_CONSUMER_INIT(&sc->inbuf,buf);
1608 		MIDI_IN_UNLOCK(sc,s);
1609 		*(int *)addr = buf_lim - buf_cur;
1610 		break;
1611 
1612 	case FIOASYNC:
1613 		if (*(int *)addr) {
1614 			if (sc->async)
1615 				return EBUSY;
1616 			sc->async = l->l_proc;
1617 			DPRINTFN(5,("midi_ioctl: FIOASYNC %p\n", l->l_proc));
1618 		} else
1619 			sc->async = 0;
1620 		break;
1621 
1622 #if 0
1623 	case MIDI_PRETIME:
1624 		/* XXX OSS
1625 		 * This should set up a read timeout, but that's
1626 		 * why we have poll(), so there's nothing yet. */
1627 		error = EINVAL;
1628 		break;
1629 #endif
1630 
1631 #ifdef MIDI_SAVE
1632 	case MIDI_GETSAVE:
1633 		error = copyout(&midisave, *(void **)addr, sizeof midisave);
1634   		break;
1635 #endif
1636 
1637 	default:
1638 		if (hw->ioctl)
1639 			error = hw->ioctl(sc->hw_hdl, cmd, addr, flag, l);
1640 		else
1641 			error = EINVAL;
1642 		break;
1643 	}
1644 	return error;
1645 }
1646 
1647 int
1648 midipoll(dev_t dev, int events, struct lwp *l)
1649 {
1650 	int unit = MIDIUNIT(dev);
1651 	struct midi_softc *sc = midi_cd.cd_devs[unit];
1652 	int revents = 0;
1653 	int s;
1654 	MIDI_BUF_DECLARE(idx);
1655 	MIDI_BUF_DECLARE(buf);
1656 
1657 	DPRINTFN(6,("midipoll: %p events=0x%x\n", sc, events));
1658 
1659 	if (sc->dying)
1660 		return POLLHUP;
1661 
1662 	s = splaudio();
1663 
1664 	if ((sc->flags&FREAD) && (events & (POLLIN | POLLRDNORM))) {
1665 		simple_lock(&sc->in_lock);
1666 		MIDI_BUF_CONSUMER_INIT(&sc->inbuf,idx);
1667 		if (idx_cur < idx_lim)
1668 			revents |= events & (POLLIN | POLLRDNORM);
1669 		else
1670 			selrecord(l, &sc->rsel);
1671 		simple_unlock(&sc->in_lock);
1672 	}
1673 
1674 	if ((sc->flags&FWRITE) && (events & (POLLOUT | POLLWRNORM))) {
1675 		simple_lock(&sc->out_lock);
1676 		MIDI_BUF_PRODUCER_INIT(&sc->outbuf,idx);
1677 		MIDI_BUF_PRODUCER_INIT(&sc->outbuf,buf);
1678 		if ( idx_lim - idx_cur >= 1  &&  buf_lim - buf_cur >= 3 )
1679 			revents |= events & (POLLOUT | POLLWRNORM);
1680 		else
1681 			selrecord(l, &sc->wsel);
1682 		simple_unlock(&sc->out_lock);
1683 	}
1684 
1685 	splx(s);
1686 	return revents;
1687 }
1688 
1689 static void
1690 filt_midirdetach(struct knote *kn)
1691 {
1692 	struct midi_softc *sc = kn->kn_hook;
1693 	int s;
1694 
1695 	s = splaudio();
1696 	SLIST_REMOVE(&sc->rsel.sel_klist, kn, knote, kn_selnext);
1697 	splx(s);
1698 }
1699 
1700 static int
1701 filt_midiread(struct knote *kn, long hint)
1702 {
1703 	struct midi_softc *sc = kn->kn_hook;
1704 	int s;
1705 	MIDI_BUF_DECLARE(buf);
1706 
1707 	/* XXXLUKEM (thorpej): please make sure this is correct. */
1708 
1709 	MIDI_IN_LOCK(sc,s);
1710 	MIDI_BUF_CONSUMER_INIT(&sc->inbuf,buf);
1711 	kn->kn_data = buf_lim - buf_cur;
1712 	MIDI_IN_UNLOCK(sc,s);
1713 	return (kn->kn_data > 0);
1714 }
1715 
1716 static const struct filterops midiread_filtops =
1717 	{ 1, NULL, filt_midirdetach, filt_midiread };
1718 
1719 static void
1720 filt_midiwdetach(struct knote *kn)
1721 {
1722 	struct midi_softc *sc = kn->kn_hook;
1723 	int s;
1724 
1725 	s = splaudio();
1726 	SLIST_REMOVE(&sc->wsel.sel_klist, kn, knote, kn_selnext);
1727 	splx(s);
1728 }
1729 
1730 static int
1731 filt_midiwrite(struct knote *kn, long hint)
1732 {
1733 	struct midi_softc *sc = kn->kn_hook;
1734 	int s;
1735 	MIDI_BUF_DECLARE(idx);
1736 	MIDI_BUF_DECLARE(buf);
1737 
1738 	/* XXXLUKEM (thorpej): please make sure this is correct. */
1739 
1740 	MIDI_OUT_LOCK(sc,s);
1741 	MIDI_BUF_PRODUCER_INIT(&sc->outbuf,idx);
1742 	MIDI_BUF_PRODUCER_INIT(&sc->outbuf,buf);
1743 	kn->kn_data = ((buf_lim - buf_cur)-1)>>1;
1744 	if ( kn->kn_data > idx_lim - idx_cur )
1745 		kn->kn_data = idx_lim - idx_cur;
1746 	MIDI_OUT_UNLOCK(sc,s);
1747 	return (kn->kn_data > 0);
1748 }
1749 
1750 static const struct filterops midiwrite_filtops =
1751 	{ 1, NULL, filt_midiwdetach, filt_midiwrite };
1752 
1753 int
1754 midikqfilter(dev_t dev, struct knote *kn)
1755 {
1756 	int unit = MIDIUNIT(dev);
1757 	struct midi_softc *sc = midi_cd.cd_devs[unit];
1758 	struct klist *klist;
1759 	int s;
1760 
1761 	switch (kn->kn_filter) {
1762 	case EVFILT_READ:
1763 		klist = &sc->rsel.sel_klist;
1764 		kn->kn_fop = &midiread_filtops;
1765 		break;
1766 
1767 	case EVFILT_WRITE:
1768 		klist = &sc->wsel.sel_klist;
1769 		kn->kn_fop = &midiwrite_filtops;
1770 		break;
1771 
1772 	default:
1773 		return (EINVAL);
1774 	}
1775 
1776 	kn->kn_hook = sc;
1777 
1778 	s = splaudio();
1779 	SLIST_INSERT_HEAD(klist, kn, kn_selnext);
1780 	splx(s);
1781 
1782 	return (0);
1783 }
1784 
1785 void
1786 midi_getinfo(dev_t dev, struct midi_info *mi)
1787 {
1788 	struct midi_softc *sc;
1789 
1790 	sc = device_lookup(&midi_cd, MIDIUNIT(dev));
1791 	if (sc == NULL)
1792 		return;
1793 	if (sc->dying)
1794 		return;
1795 
1796 	sc->hw_if->getinfo(sc->hw_hdl, mi);
1797 }
1798 
1799 #elif NMIDIBUS > 0 /* but NMIDI == 0 */
1800 
1801 void midi_register_hw_if_ext(struct midi_hw_if_ext *exthw) { /* stub */
1802 }
1803 
1804 #endif /* NMIDI > 0 */
1805 
1806 #if NMIDI > 0 || NMIDIBUS > 0
1807 
1808 int	audioprint(void *, const char *);
1809 
1810 struct device *
1811 midi_attach_mi(const struct midi_hw_if *mhwp, void *hdlp, struct device *dev)
1812 {
1813 	struct audio_attach_args arg;
1814 
1815 #ifdef DIAGNOSTIC
1816 	if (mhwp == NULL) {
1817 		aprint_error("midi_attach_mi: NULL\n");
1818 		return (0);
1819 	}
1820 #endif
1821 	arg.type = AUDIODEV_TYPE_MIDI;
1822 	arg.hwif = mhwp;
1823 	arg.hdl = hdlp;
1824 	return (config_found(dev, &arg, audioprint));
1825 }
1826 
1827 #endif /* NMIDI > 0 || NMIDIBUS > 0 */
1828