xref: /openbmc/linux/sound/core/seq/seq_midi_event.c (revision cff4fa84) 
1 /*
2  *  MIDI byte <-> sequencer event coder
3  *
4  *  Copyright (C) 1998,99 Takashi Iwai <tiwai@suse.de>,
5  *                        Jaroslav Kysela <perex@perex.cz>
6  *
7  *   This program is free software; you can redistribute it and/or modify
8  *   it under the terms of the GNU General Public License as published by
9  *   the Free Software Foundation; either version 2 of the License, or
10  *   (at your option) any later version.
11  *
12  *   This program is distributed in the hope that it will be useful,
13  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
14  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15  *   GNU General Public License for more details.
16  *
17  *   You should have received a copy of the GNU General Public License
18  *   along with this program; if not, write to the Free Software
19  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
20  */
21 
22 #include <linux/slab.h>
23 #include <linux/errno.h>
24 #include <linux/string.h>
25 #include <sound/core.h>
26 #include <sound/seq_kernel.h>
27 #include <sound/seq_midi_event.h>
28 #include <sound/asoundef.h>
29 
30 MODULE_AUTHOR("Takashi Iwai <tiwai@suse.de>, Jaroslav Kysela <perex@perex.cz>");
31 MODULE_DESCRIPTION("MIDI byte <-> sequencer event coder");
32 MODULE_LICENSE("GPL");
33 
34 /* event type, index into status_event[] */
35 /* from 0 to 6 are normal commands (note off, on, etc.) for 0x9?-0xe? */
36 #define ST_INVALID	7
37 #define ST_SPECIAL	8
38 #define ST_SYSEX	ST_SPECIAL
39 /* from 8 to 15 are events for 0xf0-0xf7 */
40 
41 
42 /*
43  * prototypes
44  */
45 static void note_event(struct snd_midi_event *dev, struct snd_seq_event *ev);
46 static void one_param_ctrl_event(struct snd_midi_event *dev, struct snd_seq_event *ev);
47 static void pitchbend_ctrl_event(struct snd_midi_event *dev, struct snd_seq_event *ev);
48 static void two_param_ctrl_event(struct snd_midi_event *dev, struct snd_seq_event *ev);
49 static void one_param_event(struct snd_midi_event *dev, struct snd_seq_event *ev);
50 static void songpos_event(struct snd_midi_event *dev, struct snd_seq_event *ev);
51 static void note_decode(struct snd_seq_event *ev, unsigned char *buf);
52 static void one_param_decode(struct snd_seq_event *ev, unsigned char *buf);
53 static void pitchbend_decode(struct snd_seq_event *ev, unsigned char *buf);
54 static void two_param_decode(struct snd_seq_event *ev, unsigned char *buf);
55 static void songpos_decode(struct snd_seq_event *ev, unsigned char *buf);
56 
57 /*
58  * event list
59  */
60 static struct status_event_list {
61 	int event;
62 	int qlen;
63 	void (*encode)(struct snd_midi_event *dev, struct snd_seq_event *ev);
64 	void (*decode)(struct snd_seq_event *ev, unsigned char *buf);
65 } status_event[] = {
66 	/* 0x80 - 0xef */
67 	{SNDRV_SEQ_EVENT_NOTEOFF,	 2, note_event, note_decode},
68 	{SNDRV_SEQ_EVENT_NOTEON,	 2, note_event, note_decode},
69 	{SNDRV_SEQ_EVENT_KEYPRESS,	 2, note_event, note_decode},
70 	{SNDRV_SEQ_EVENT_CONTROLLER,	 2, two_param_ctrl_event, two_param_decode},
71 	{SNDRV_SEQ_EVENT_PGMCHANGE,	 1, one_param_ctrl_event, one_param_decode},
72 	{SNDRV_SEQ_EVENT_CHANPRESS,	 1, one_param_ctrl_event, one_param_decode},
73 	{SNDRV_SEQ_EVENT_PITCHBEND,	 2, pitchbend_ctrl_event, pitchbend_decode},
74 	/* invalid */
75 	{SNDRV_SEQ_EVENT_NONE,		-1, NULL, NULL},
76 	/* 0xf0 - 0xff */
77 	{SNDRV_SEQ_EVENT_SYSEX,		 1, NULL, NULL}, /* sysex: 0xf0 */
78 	{SNDRV_SEQ_EVENT_QFRAME,	 1, one_param_event, one_param_decode}, /* 0xf1 */
79 	{SNDRV_SEQ_EVENT_SONGPOS,	 2, songpos_event, songpos_decode}, /* 0xf2 */
80 	{SNDRV_SEQ_EVENT_SONGSEL,	 1, one_param_event, one_param_decode}, /* 0xf3 */
81 	{SNDRV_SEQ_EVENT_NONE,		-1, NULL, NULL}, /* 0xf4 */
82 	{SNDRV_SEQ_EVENT_NONE,		-1, NULL, NULL}, /* 0xf5 */
83 	{SNDRV_SEQ_EVENT_TUNE_REQUEST,	 0, NULL, NULL}, /* 0xf6 */
84 	{SNDRV_SEQ_EVENT_NONE,		-1, NULL, NULL}, /* 0xf7 */
85 	{SNDRV_SEQ_EVENT_CLOCK,		 0, NULL, NULL}, /* 0xf8 */
86 	{SNDRV_SEQ_EVENT_NONE,		-1, NULL, NULL}, /* 0xf9 */
87 	{SNDRV_SEQ_EVENT_START,		 0, NULL, NULL}, /* 0xfa */
88 	{SNDRV_SEQ_EVENT_CONTINUE,	 0, NULL, NULL}, /* 0xfb */
89 	{SNDRV_SEQ_EVENT_STOP, 		 0, NULL, NULL}, /* 0xfc */
90 	{SNDRV_SEQ_EVENT_NONE, 		-1, NULL, NULL}, /* 0xfd */
91 	{SNDRV_SEQ_EVENT_SENSING, 	 0, NULL, NULL}, /* 0xfe */
92 	{SNDRV_SEQ_EVENT_RESET, 	 0, NULL, NULL}, /* 0xff */
93 };
94 
95 static int extra_decode_ctrl14(struct snd_midi_event *dev, unsigned char *buf, int len,
96 			       struct snd_seq_event *ev);
97 static int extra_decode_xrpn(struct snd_midi_event *dev, unsigned char *buf, int count,
98 			     struct snd_seq_event *ev);
99 
100 static struct extra_event_list {
101 	int event;
102 	int (*decode)(struct snd_midi_event *dev, unsigned char *buf, int len,
103 		      struct snd_seq_event *ev);
104 } extra_event[] = {
105 	{SNDRV_SEQ_EVENT_CONTROL14, extra_decode_ctrl14},
106 	{SNDRV_SEQ_EVENT_NONREGPARAM, extra_decode_xrpn},
107 	{SNDRV_SEQ_EVENT_REGPARAM, extra_decode_xrpn},
108 };
109 
110 /*
111  *  new/delete record
112  */
113 
114 int snd_midi_event_new(int bufsize, struct snd_midi_event **rdev)
115 {
116 	struct snd_midi_event *dev;
117 
118 	*rdev = NULL;
119 	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
120 	if (dev == NULL)
121 		return -ENOMEM;
122 	if (bufsize > 0) {
123 		dev->buf = kmalloc(bufsize, GFP_KERNEL);
124 		if (dev->buf == NULL) {
125 			kfree(dev);
126 			return -ENOMEM;
127 		}
128 	}
129 	dev->bufsize = bufsize;
130 	dev->lastcmd = 0xff;
131 	dev->type = ST_INVALID;
132 	spin_lock_init(&dev->lock);
133 	*rdev = dev;
134 	return 0;
135 }
136 
137 void snd_midi_event_free(struct snd_midi_event *dev)
138 {
139 	if (dev != NULL) {
140 		kfree(dev->buf);
141 		kfree(dev);
142 	}
143 }
144 
145 /*
146  * initialize record
147  */
148 static inline void reset_encode(struct snd_midi_event *dev)
149 {
150 	dev->read = 0;
151 	dev->qlen = 0;
152 	dev->type = ST_INVALID;
153 }
154 
155 void snd_midi_event_reset_encode(struct snd_midi_event *dev)
156 {
157 	unsigned long flags;
158 
159 	spin_lock_irqsave(&dev->lock, flags);
160 	reset_encode(dev);
161 	spin_unlock_irqrestore(&dev->lock, flags);
162 }
163 
164 void snd_midi_event_reset_decode(struct snd_midi_event *dev)
165 {
166 	unsigned long flags;
167 
168 	spin_lock_irqsave(&dev->lock, flags);
169 	dev->lastcmd = 0xff;
170 	spin_unlock_irqrestore(&dev->lock, flags);
171 }
172 
173 #if 0
174 void snd_midi_event_init(struct snd_midi_event *dev)
175 {
176 	snd_midi_event_reset_encode(dev);
177 	snd_midi_event_reset_decode(dev);
178 }
179 #endif  /*  0  */
180 
181 void snd_midi_event_no_status(struct snd_midi_event *dev, int on)
182 {
183 	dev->nostat = on ? 1 : 0;
184 }
185 
186 /*
187  * resize buffer
188  */
189 #if 0
190 int snd_midi_event_resize_buffer(struct snd_midi_event *dev, int bufsize)
191 {
192 	unsigned char *new_buf, *old_buf;
193 	unsigned long flags;
194 
195 	if (bufsize == dev->bufsize)
196 		return 0;
197 	new_buf = kmalloc(bufsize, GFP_KERNEL);
198 	if (new_buf == NULL)
199 		return -ENOMEM;
200 	spin_lock_irqsave(&dev->lock, flags);
201 	old_buf = dev->buf;
202 	dev->buf = new_buf;
203 	dev->bufsize = bufsize;
204 	reset_encode(dev);
205 	spin_unlock_irqrestore(&dev->lock, flags);
206 	kfree(old_buf);
207 	return 0;
208 }
209 #endif  /*  0  */
210 
211 /*
212  *  read bytes and encode to sequencer event if finished
213  *  return the size of encoded bytes
214  */
215 long snd_midi_event_encode(struct snd_midi_event *dev, unsigned char *buf, long count,
216 			   struct snd_seq_event *ev)
217 {
218 	long result = 0;
219 	int rc;
220 
221 	ev->type = SNDRV_SEQ_EVENT_NONE;
222 
223 	while (count-- > 0) {
224 		rc = snd_midi_event_encode_byte(dev, *buf++, ev);
225 		result++;
226 		if (rc < 0)
227 			return rc;
228 		else if (rc > 0)
229 			return result;
230 	}
231 
232 	return result;
233 }
234 
235 /*
236  *  read one byte and encode to sequencer event:
237  *  return 1 if MIDI bytes are encoded to an event
238  *         0 data is not finished
239  *         negative for error
240  */
241 int snd_midi_event_encode_byte(struct snd_midi_event *dev, int c,
242 			       struct snd_seq_event *ev)
243 {
244 	int rc = 0;
245 	unsigned long flags;
246 
247 	c &= 0xff;
248 
249 	if (c >= MIDI_CMD_COMMON_CLOCK) {
250 		/* real-time event */
251 		ev->type = status_event[ST_SPECIAL + c - 0xf0].event;
252 		ev->flags &= ~SNDRV_SEQ_EVENT_LENGTH_MASK;
253 		ev->flags |= SNDRV_SEQ_EVENT_LENGTH_FIXED;
254 		return ev->type != SNDRV_SEQ_EVENT_NONE;
255 	}
256 
257 	spin_lock_irqsave(&dev->lock, flags);
258 	if ((c & 0x80) &&
259 	    (c != MIDI_CMD_COMMON_SYSEX_END || dev->type != ST_SYSEX)) {
260 		/* new command */
261 		dev->buf[0] = c;
262 		if ((c & 0xf0) == 0xf0) /* system messages */
263 			dev->type = (c & 0x0f) + ST_SPECIAL;
264 		else
265 			dev->type = (c >> 4) & 0x07;
266 		dev->read = 1;
267 		dev->qlen = status_event[dev->type].qlen;
268 	} else {
269 		if (dev->qlen > 0) {
270 			/* rest of command */
271 			dev->buf[dev->read++] = c;
272 			if (dev->type != ST_SYSEX)
273 				dev->qlen--;
274 		} else {
275 			/* running status */
276 			dev->buf[1] = c;
277 			dev->qlen = status_event[dev->type].qlen - 1;
278 			dev->read = 2;
279 		}
280 	}
281 	if (dev->qlen == 0) {
282 		ev->type = status_event[dev->type].event;
283 		ev->flags &= ~SNDRV_SEQ_EVENT_LENGTH_MASK;
284 		ev->flags |= SNDRV_SEQ_EVENT_LENGTH_FIXED;
285 		if (status_event[dev->type].encode) /* set data values */
286 			status_event[dev->type].encode(dev, ev);
287 		if (dev->type >= ST_SPECIAL)
288 			dev->type = ST_INVALID;
289 		rc = 1;
290 	} else 	if (dev->type == ST_SYSEX) {
291 		if (c == MIDI_CMD_COMMON_SYSEX_END ||
292 		    dev->read >= dev->bufsize) {
293 			ev->flags &= ~SNDRV_SEQ_EVENT_LENGTH_MASK;
294 			ev->flags |= SNDRV_SEQ_EVENT_LENGTH_VARIABLE;
295 			ev->type = SNDRV_SEQ_EVENT_SYSEX;
296 			ev->data.ext.len = dev->read;
297 			ev->data.ext.ptr = dev->buf;
298 			if (c != MIDI_CMD_COMMON_SYSEX_END)
299 				dev->read = 0; /* continue to parse */
300 			else
301 				reset_encode(dev); /* all parsed */
302 			rc = 1;
303 		}
304 	}
305 
306 	spin_unlock_irqrestore(&dev->lock, flags);
307 	return rc;
308 }
309 
310 /* encode note event */
311 static void note_event(struct snd_midi_event *dev, struct snd_seq_event *ev)
312 {
313 	ev->data.note.channel = dev->buf[0] & 0x0f;
314 	ev->data.note.note = dev->buf[1];
315 	ev->data.note.velocity = dev->buf[2];
316 }
317 
318 /* encode one parameter controls */
319 static void one_param_ctrl_event(struct snd_midi_event *dev, struct snd_seq_event *ev)
320 {
321 	ev->data.control.channel = dev->buf[0] & 0x0f;
322 	ev->data.control.value = dev->buf[1];
323 }
324 
325 /* encode pitch wheel change */
326 static void pitchbend_ctrl_event(struct snd_midi_event *dev, struct snd_seq_event *ev)
327 {
328 	ev->data.control.channel = dev->buf[0] & 0x0f;
329 	ev->data.control.value = (int)dev->buf[2] * 128 + (int)dev->buf[1] - 8192;
330 }
331 
332 /* encode midi control change */
333 static void two_param_ctrl_event(struct snd_midi_event *dev, struct snd_seq_event *ev)
334 {
335 	ev->data.control.channel = dev->buf[0] & 0x0f;
336 	ev->data.control.param = dev->buf[1];
337 	ev->data.control.value = dev->buf[2];
338 }
339 
340 /* encode one parameter value*/
341 static void one_param_event(struct snd_midi_event *dev, struct snd_seq_event *ev)
342 {
343 	ev->data.control.value = dev->buf[1];
344 }
345 
346 /* encode song position */
347 static void songpos_event(struct snd_midi_event *dev, struct snd_seq_event *ev)
348 {
349 	ev->data.control.value = (int)dev->buf[2] * 128 + (int)dev->buf[1];
350 }
351 
352 /*
353  * decode from a sequencer event to midi bytes
354  * return the size of decoded midi events
355  */
356 long snd_midi_event_decode(struct snd_midi_event *dev, unsigned char *buf, long count,
357 			   struct snd_seq_event *ev)
358 {
359 	unsigned int cmd, type;
360 
361 	if (ev->type == SNDRV_SEQ_EVENT_NONE)
362 		return -ENOENT;
363 
364 	for (type = 0; type < ARRAY_SIZE(status_event); type++) {
365 		if (ev->type == status_event[type].event)
366 			goto __found;
367 	}
368 	for (type = 0; type < ARRAY_SIZE(extra_event); type++) {
369 		if (ev->type == extra_event[type].event)
370 			return extra_event[type].decode(dev, buf, count, ev);
371 	}
372 	return -ENOENT;
373 
374       __found:
375 	if (type >= ST_SPECIAL)
376 		cmd = 0xf0 + (type - ST_SPECIAL);
377 	else
378 		/* data.note.channel and data.control.channel is identical */
379 		cmd = 0x80 | (type << 4) | (ev->data.note.channel & 0x0f);
380 
381 
382 	if (cmd == MIDI_CMD_COMMON_SYSEX) {
383 		snd_midi_event_reset_decode(dev);
384 		return snd_seq_expand_var_event(ev, count, buf, 1, 0);
385 	} else {
386 		int qlen;
387 		unsigned char xbuf[4];
388 		unsigned long flags;
389 
390 		spin_lock_irqsave(&dev->lock, flags);
391 		if ((cmd & 0xf0) == 0xf0 || dev->lastcmd != cmd || dev->nostat) {
392 			dev->lastcmd = cmd;
393 			spin_unlock_irqrestore(&dev->lock, flags);
394 			xbuf[0] = cmd;
395 			if (status_event[type].decode)
396 				status_event[type].decode(ev, xbuf + 1);
397 			qlen = status_event[type].qlen + 1;
398 		} else {
399 			spin_unlock_irqrestore(&dev->lock, flags);
400 			if (status_event[type].decode)
401 				status_event[type].decode(ev, xbuf + 0);
402 			qlen = status_event[type].qlen;
403 		}
404 		if (count < qlen)
405 			return -ENOMEM;
406 		memcpy(buf, xbuf, qlen);
407 		return qlen;
408 	}
409 }
410 
411 
412 /* decode note event */
413 static void note_decode(struct snd_seq_event *ev, unsigned char *buf)
414 {
415 	buf[0] = ev->data.note.note & 0x7f;
416 	buf[1] = ev->data.note.velocity & 0x7f;
417 }
418 
419 /* decode one parameter controls */
420 static void one_param_decode(struct snd_seq_event *ev, unsigned char *buf)
421 {
422 	buf[0] = ev->data.control.value & 0x7f;
423 }
424 
425 /* decode pitch wheel change */
426 static void pitchbend_decode(struct snd_seq_event *ev, unsigned char *buf)
427 {
428 	int value = ev->data.control.value + 8192;
429 	buf[0] = value & 0x7f;
430 	buf[1] = (value >> 7) & 0x7f;
431 }
432 
433 /* decode midi control change */
434 static void two_param_decode(struct snd_seq_event *ev, unsigned char *buf)
435 {
436 	buf[0] = ev->data.control.param & 0x7f;
437 	buf[1] = ev->data.control.value & 0x7f;
438 }
439 
440 /* decode song position */
441 static void songpos_decode(struct snd_seq_event *ev, unsigned char *buf)
442 {
443 	buf[0] = ev->data.control.value & 0x7f;
444 	buf[1] = (ev->data.control.value >> 7) & 0x7f;
445 }
446 
447 /* decode 14bit control */
448 static int extra_decode_ctrl14(struct snd_midi_event *dev, unsigned char *buf,
449 			       int count, struct snd_seq_event *ev)
450 {
451 	unsigned char cmd;
452 	int idx = 0;
453 
454 	cmd = MIDI_CMD_CONTROL|(ev->data.control.channel & 0x0f);
455 	if (ev->data.control.param < 0x20) {
456 		if (count < 4)
457 			return -ENOMEM;
458 		if (dev->nostat && count < 6)
459 			return -ENOMEM;
460 		if (cmd != dev->lastcmd || dev->nostat) {
461 			if (count < 5)
462 				return -ENOMEM;
463 			buf[idx++] = dev->lastcmd = cmd;
464 		}
465 		buf[idx++] = ev->data.control.param;
466 		buf[idx++] = (ev->data.control.value >> 7) & 0x7f;
467 		if (dev->nostat)
468 			buf[idx++] = cmd;
469 		buf[idx++] = ev->data.control.param + 0x20;
470 		buf[idx++] = ev->data.control.value & 0x7f;
471 	} else {
472 		if (count < 2)
473 			return -ENOMEM;
474 		if (cmd != dev->lastcmd || dev->nostat) {
475 			if (count < 3)
476 				return -ENOMEM;
477 			buf[idx++] = dev->lastcmd = cmd;
478 		}
479 		buf[idx++] = ev->data.control.param & 0x7f;
480 		buf[idx++] = ev->data.control.value & 0x7f;
481 	}
482 	return idx;
483 }
484 
485 /* decode reg/nonreg param */
486 static int extra_decode_xrpn(struct snd_midi_event *dev, unsigned char *buf,
487 			     int count, struct snd_seq_event *ev)
488 {
489 	unsigned char cmd;
490 	char *cbytes;
491 	static char cbytes_nrpn[4] = { MIDI_CTL_NONREG_PARM_NUM_MSB,
492 				       MIDI_CTL_NONREG_PARM_NUM_LSB,
493 				       MIDI_CTL_MSB_DATA_ENTRY,
494 				       MIDI_CTL_LSB_DATA_ENTRY };
495 	static char cbytes_rpn[4] =  { MIDI_CTL_REGIST_PARM_NUM_MSB,
496 				       MIDI_CTL_REGIST_PARM_NUM_LSB,
497 				       MIDI_CTL_MSB_DATA_ENTRY,
498 				       MIDI_CTL_LSB_DATA_ENTRY };
499 	unsigned char bytes[4];
500 	int idx = 0, i;
501 
502 	if (count < 8)
503 		return -ENOMEM;
504 	if (dev->nostat && count < 12)
505 		return -ENOMEM;
506 	cmd = MIDI_CMD_CONTROL|(ev->data.control.channel & 0x0f);
507 	bytes[0] = (ev->data.control.param & 0x3f80) >> 7;
508 	bytes[1] = ev->data.control.param & 0x007f;
509 	bytes[2] = (ev->data.control.value & 0x3f80) >> 7;
510 	bytes[3] = ev->data.control.value & 0x007f;
511 	if (cmd != dev->lastcmd && !dev->nostat) {
512 		if (count < 9)
513 			return -ENOMEM;
514 		buf[idx++] = dev->lastcmd = cmd;
515 	}
516 	cbytes = ev->type == SNDRV_SEQ_EVENT_NONREGPARAM ? cbytes_nrpn : cbytes_rpn;
517 	for (i = 0; i < 4; i++) {
518 		if (dev->nostat)
519 			buf[idx++] = dev->lastcmd = cmd;
520 		buf[idx++] = cbytes[i];
521 		buf[idx++] = bytes[i];
522 	}
523 	return idx;
524 }
525 
526 /*
527  *  exports
528  */
529 
530 EXPORT_SYMBOL(snd_midi_event_new);
531 EXPORT_SYMBOL(snd_midi_event_free);
532 EXPORT_SYMBOL(snd_midi_event_reset_encode);
533 EXPORT_SYMBOL(snd_midi_event_reset_decode);
534 EXPORT_SYMBOL(snd_midi_event_no_status);
535 EXPORT_SYMBOL(snd_midi_event_encode);
536 EXPORT_SYMBOL(snd_midi_event_encode_byte);
537 EXPORT_SYMBOL(snd_midi_event_decode);
538 
539 static int __init alsa_seq_midi_event_init(void)
540 {
541 	return 0;
542 }
543 
544 static void __exit alsa_seq_midi_event_exit(void)
545 {
546 }
547 
548 module_init(alsa_seq_midi_event_init)
549 module_exit(alsa_seq_midi_event_exit)
550