xref: /openbmc/linux/sound/core/seq/seq_midi_event.c (revision ba61bb17) 
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 <linux/module.h>
26 #include <sound/core.h>
27 #include <sound/seq_kernel.h>
28 #include <sound/seq_midi_event.h>
29 #include <sound/asoundef.h>
30 
31 MODULE_AUTHOR("Takashi Iwai <tiwai@suse.de>, Jaroslav Kysela <perex@perex.cz>");
32 MODULE_DESCRIPTION("MIDI byte <-> sequencer event coder");
33 MODULE_LICENSE("GPL");
34 
35 /* event type, index into status_event[] */
36 /* from 0 to 6 are normal commands (note off, on, etc.) for 0x9?-0xe? */
37 #define ST_INVALID	7
38 #define ST_SPECIAL	8
39 #define ST_SYSEX	ST_SPECIAL
40 /* from 8 to 15 are events for 0xf0-0xf7 */
41 
42 
43 /*
44  * prototypes
45  */
46 static void note_event(struct snd_midi_event *dev, struct snd_seq_event *ev);
47 static void one_param_ctrl_event(struct snd_midi_event *dev, struct snd_seq_event *ev);
48 static void pitchbend_ctrl_event(struct snd_midi_event *dev, struct snd_seq_event *ev);
49 static void two_param_ctrl_event(struct snd_midi_event *dev, struct snd_seq_event *ev);
50 static void one_param_event(struct snd_midi_event *dev, struct snd_seq_event *ev);
51 static void songpos_event(struct snd_midi_event *dev, struct snd_seq_event *ev);
52 static void note_decode(struct snd_seq_event *ev, unsigned char *buf);
53 static void one_param_decode(struct snd_seq_event *ev, unsigned char *buf);
54 static void pitchbend_decode(struct snd_seq_event *ev, unsigned char *buf);
55 static void two_param_decode(struct snd_seq_event *ev, unsigned char *buf);
56 static void songpos_decode(struct snd_seq_event *ev, unsigned char *buf);
57 
58 /*
59  * event list
60  */
61 static struct status_event_list {
62 	int event;
63 	int qlen;
64 	void (*encode)(struct snd_midi_event *dev, struct snd_seq_event *ev);
65 	void (*decode)(struct snd_seq_event *ev, unsigned char *buf);
66 } status_event[] = {
67 	/* 0x80 - 0xef */
68 	{SNDRV_SEQ_EVENT_NOTEOFF,	 2, note_event, note_decode},
69 	{SNDRV_SEQ_EVENT_NOTEON,	 2, note_event, note_decode},
70 	{SNDRV_SEQ_EVENT_KEYPRESS,	 2, note_event, note_decode},
71 	{SNDRV_SEQ_EVENT_CONTROLLER,	 2, two_param_ctrl_event, two_param_decode},
72 	{SNDRV_SEQ_EVENT_PGMCHANGE,	 1, one_param_ctrl_event, one_param_decode},
73 	{SNDRV_SEQ_EVENT_CHANPRESS,	 1, one_param_ctrl_event, one_param_decode},
74 	{SNDRV_SEQ_EVENT_PITCHBEND,	 2, pitchbend_ctrl_event, pitchbend_decode},
75 	/* invalid */
76 	{SNDRV_SEQ_EVENT_NONE,		-1, NULL, NULL},
77 	/* 0xf0 - 0xff */
78 	{SNDRV_SEQ_EVENT_SYSEX,		 1, NULL, NULL}, /* sysex: 0xf0 */
79 	{SNDRV_SEQ_EVENT_QFRAME,	 1, one_param_event, one_param_decode}, /* 0xf1 */
80 	{SNDRV_SEQ_EVENT_SONGPOS,	 2, songpos_event, songpos_decode}, /* 0xf2 */
81 	{SNDRV_SEQ_EVENT_SONGSEL,	 1, one_param_event, one_param_decode}, /* 0xf3 */
82 	{SNDRV_SEQ_EVENT_NONE,		-1, NULL, NULL}, /* 0xf4 */
83 	{SNDRV_SEQ_EVENT_NONE,		-1, NULL, NULL}, /* 0xf5 */
84 	{SNDRV_SEQ_EVENT_TUNE_REQUEST,	 0, NULL, NULL}, /* 0xf6 */
85 	{SNDRV_SEQ_EVENT_NONE,		-1, NULL, NULL}, /* 0xf7 */
86 	{SNDRV_SEQ_EVENT_CLOCK,		 0, NULL, NULL}, /* 0xf8 */
87 	{SNDRV_SEQ_EVENT_NONE,		-1, NULL, NULL}, /* 0xf9 */
88 	{SNDRV_SEQ_EVENT_START,		 0, NULL, NULL}, /* 0xfa */
89 	{SNDRV_SEQ_EVENT_CONTINUE,	 0, NULL, NULL}, /* 0xfb */
90 	{SNDRV_SEQ_EVENT_STOP, 		 0, NULL, NULL}, /* 0xfc */
91 	{SNDRV_SEQ_EVENT_NONE, 		-1, NULL, NULL}, /* 0xfd */
92 	{SNDRV_SEQ_EVENT_SENSING, 	 0, NULL, NULL}, /* 0xfe */
93 	{SNDRV_SEQ_EVENT_RESET, 	 0, NULL, NULL}, /* 0xff */
94 };
95 
96 static int extra_decode_ctrl14(struct snd_midi_event *dev, unsigned char *buf, int len,
97 			       struct snd_seq_event *ev);
98 static int extra_decode_xrpn(struct snd_midi_event *dev, unsigned char *buf, int count,
99 			     struct snd_seq_event *ev);
100 
101 static struct extra_event_list {
102 	int event;
103 	int (*decode)(struct snd_midi_event *dev, unsigned char *buf, int len,
104 		      struct snd_seq_event *ev);
105 } extra_event[] = {
106 	{SNDRV_SEQ_EVENT_CONTROL14, extra_decode_ctrl14},
107 	{SNDRV_SEQ_EVENT_NONREGPARAM, extra_decode_xrpn},
108 	{SNDRV_SEQ_EVENT_REGPARAM, extra_decode_xrpn},
109 };
110 
111 /*
112  *  new/delete record
113  */
114 
115 int snd_midi_event_new(int bufsize, struct snd_midi_event **rdev)
116 {
117 	struct snd_midi_event *dev;
118 
119 	*rdev = NULL;
120 	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
121 	if (dev == NULL)
122 		return -ENOMEM;
123 	if (bufsize > 0) {
124 		dev->buf = kmalloc(bufsize, GFP_KERNEL);
125 		if (dev->buf == NULL) {
126 			kfree(dev);
127 			return -ENOMEM;
128 		}
129 	}
130 	dev->bufsize = bufsize;
131 	dev->lastcmd = 0xff;
132 	dev->type = ST_INVALID;
133 	spin_lock_init(&dev->lock);
134 	*rdev = dev;
135 	return 0;
136 }
137 EXPORT_SYMBOL(snd_midi_event_new);
138 
139 void snd_midi_event_free(struct snd_midi_event *dev)
140 {
141 	if (dev != NULL) {
142 		kfree(dev->buf);
143 		kfree(dev);
144 	}
145 }
146 EXPORT_SYMBOL(snd_midi_event_free);
147 
148 /*
149  * initialize record
150  */
151 static inline void reset_encode(struct snd_midi_event *dev)
152 {
153 	dev->read = 0;
154 	dev->qlen = 0;
155 	dev->type = ST_INVALID;
156 }
157 
158 void snd_midi_event_reset_encode(struct snd_midi_event *dev)
159 {
160 	unsigned long flags;
161 
162 	spin_lock_irqsave(&dev->lock, flags);
163 	reset_encode(dev);
164 	spin_unlock_irqrestore(&dev->lock, flags);
165 }
166 EXPORT_SYMBOL(snd_midi_event_reset_encode);
167 
168 void snd_midi_event_reset_decode(struct snd_midi_event *dev)
169 {
170 	unsigned long flags;
171 
172 	spin_lock_irqsave(&dev->lock, flags);
173 	dev->lastcmd = 0xff;
174 	spin_unlock_irqrestore(&dev->lock, flags);
175 }
176 EXPORT_SYMBOL(snd_midi_event_reset_decode);
177 
178 #if 0
179 void snd_midi_event_init(struct snd_midi_event *dev)
180 {
181 	snd_midi_event_reset_encode(dev);
182 	snd_midi_event_reset_decode(dev);
183 }
184 #endif  /*  0  */
185 
186 void snd_midi_event_no_status(struct snd_midi_event *dev, int on)
187 {
188 	dev->nostat = on ? 1 : 0;
189 }
190 EXPORT_SYMBOL(snd_midi_event_no_status);
191 
192 /*
193  * resize buffer
194  */
195 #if 0
196 int snd_midi_event_resize_buffer(struct snd_midi_event *dev, int bufsize)
197 {
198 	unsigned char *new_buf, *old_buf;
199 	unsigned long flags;
200 
201 	if (bufsize == dev->bufsize)
202 		return 0;
203 	new_buf = kmalloc(bufsize, GFP_KERNEL);
204 	if (new_buf == NULL)
205 		return -ENOMEM;
206 	spin_lock_irqsave(&dev->lock, flags);
207 	old_buf = dev->buf;
208 	dev->buf = new_buf;
209 	dev->bufsize = bufsize;
210 	reset_encode(dev);
211 	spin_unlock_irqrestore(&dev->lock, flags);
212 	kfree(old_buf);
213 	return 0;
214 }
215 #endif  /*  0  */
216 
217 /*
218  *  read bytes and encode to sequencer event if finished
219  *  return the size of encoded bytes
220  */
221 long snd_midi_event_encode(struct snd_midi_event *dev, unsigned char *buf, long count,
222 			   struct snd_seq_event *ev)
223 {
224 	long result = 0;
225 	int rc;
226 
227 	ev->type = SNDRV_SEQ_EVENT_NONE;
228 
229 	while (count-- > 0) {
230 		rc = snd_midi_event_encode_byte(dev, *buf++, ev);
231 		result++;
232 		if (rc < 0)
233 			return rc;
234 		else if (rc > 0)
235 			return result;
236 	}
237 
238 	return result;
239 }
240 EXPORT_SYMBOL(snd_midi_event_encode);
241 
242 /*
243  *  read one byte and encode to sequencer event:
244  *  return 1 if MIDI bytes are encoded to an event
245  *         0 data is not finished
246  *         negative for error
247  */
248 int snd_midi_event_encode_byte(struct snd_midi_event *dev, int c,
249 			       struct snd_seq_event *ev)
250 {
251 	int rc = 0;
252 	unsigned long flags;
253 
254 	c &= 0xff;
255 
256 	if (c >= MIDI_CMD_COMMON_CLOCK) {
257 		/* real-time event */
258 		ev->type = status_event[ST_SPECIAL + c - 0xf0].event;
259 		ev->flags &= ~SNDRV_SEQ_EVENT_LENGTH_MASK;
260 		ev->flags |= SNDRV_SEQ_EVENT_LENGTH_FIXED;
261 		return ev->type != SNDRV_SEQ_EVENT_NONE;
262 	}
263 
264 	spin_lock_irqsave(&dev->lock, flags);
265 	if ((c & 0x80) &&
266 	    (c != MIDI_CMD_COMMON_SYSEX_END || dev->type != ST_SYSEX)) {
267 		/* new command */
268 		dev->buf[0] = c;
269 		if ((c & 0xf0) == 0xf0) /* system messages */
270 			dev->type = (c & 0x0f) + ST_SPECIAL;
271 		else
272 			dev->type = (c >> 4) & 0x07;
273 		dev->read = 1;
274 		dev->qlen = status_event[dev->type].qlen;
275 	} else {
276 		if (dev->qlen > 0) {
277 			/* rest of command */
278 			dev->buf[dev->read++] = c;
279 			if (dev->type != ST_SYSEX)
280 				dev->qlen--;
281 		} else {
282 			/* running status */
283 			dev->buf[1] = c;
284 			dev->qlen = status_event[dev->type].qlen - 1;
285 			dev->read = 2;
286 		}
287 	}
288 	if (dev->qlen == 0) {
289 		ev->type = status_event[dev->type].event;
290 		ev->flags &= ~SNDRV_SEQ_EVENT_LENGTH_MASK;
291 		ev->flags |= SNDRV_SEQ_EVENT_LENGTH_FIXED;
292 		if (status_event[dev->type].encode) /* set data values */
293 			status_event[dev->type].encode(dev, ev);
294 		if (dev->type >= ST_SPECIAL)
295 			dev->type = ST_INVALID;
296 		rc = 1;
297 	} else 	if (dev->type == ST_SYSEX) {
298 		if (c == MIDI_CMD_COMMON_SYSEX_END ||
299 		    dev->read >= dev->bufsize) {
300 			ev->flags &= ~SNDRV_SEQ_EVENT_LENGTH_MASK;
301 			ev->flags |= SNDRV_SEQ_EVENT_LENGTH_VARIABLE;
302 			ev->type = SNDRV_SEQ_EVENT_SYSEX;
303 			ev->data.ext.len = dev->read;
304 			ev->data.ext.ptr = dev->buf;
305 			if (c != MIDI_CMD_COMMON_SYSEX_END)
306 				dev->read = 0; /* continue to parse */
307 			else
308 				reset_encode(dev); /* all parsed */
309 			rc = 1;
310 		}
311 	}
312 
313 	spin_unlock_irqrestore(&dev->lock, flags);
314 	return rc;
315 }
316 EXPORT_SYMBOL(snd_midi_event_encode_byte);
317 
318 /* encode note event */
319 static void note_event(struct snd_midi_event *dev, struct snd_seq_event *ev)
320 {
321 	ev->data.note.channel = dev->buf[0] & 0x0f;
322 	ev->data.note.note = dev->buf[1];
323 	ev->data.note.velocity = dev->buf[2];
324 }
325 
326 /* encode one parameter controls */
327 static void one_param_ctrl_event(struct snd_midi_event *dev, struct snd_seq_event *ev)
328 {
329 	ev->data.control.channel = dev->buf[0] & 0x0f;
330 	ev->data.control.value = dev->buf[1];
331 }
332 
333 /* encode pitch wheel change */
334 static void pitchbend_ctrl_event(struct snd_midi_event *dev, struct snd_seq_event *ev)
335 {
336 	ev->data.control.channel = dev->buf[0] & 0x0f;
337 	ev->data.control.value = (int)dev->buf[2] * 128 + (int)dev->buf[1] - 8192;
338 }
339 
340 /* encode midi control change */
341 static void two_param_ctrl_event(struct snd_midi_event *dev, struct snd_seq_event *ev)
342 {
343 	ev->data.control.channel = dev->buf[0] & 0x0f;
344 	ev->data.control.param = dev->buf[1];
345 	ev->data.control.value = dev->buf[2];
346 }
347 
348 /* encode one parameter value*/
349 static void one_param_event(struct snd_midi_event *dev, struct snd_seq_event *ev)
350 {
351 	ev->data.control.value = dev->buf[1];
352 }
353 
354 /* encode song position */
355 static void songpos_event(struct snd_midi_event *dev, struct snd_seq_event *ev)
356 {
357 	ev->data.control.value = (int)dev->buf[2] * 128 + (int)dev->buf[1];
358 }
359 
360 /*
361  * decode from a sequencer event to midi bytes
362  * return the size of decoded midi events
363  */
364 long snd_midi_event_decode(struct snd_midi_event *dev, unsigned char *buf, long count,
365 			   struct snd_seq_event *ev)
366 {
367 	unsigned int cmd, type;
368 
369 	if (ev->type == SNDRV_SEQ_EVENT_NONE)
370 		return -ENOENT;
371 
372 	for (type = 0; type < ARRAY_SIZE(status_event); type++) {
373 		if (ev->type == status_event[type].event)
374 			goto __found;
375 	}
376 	for (type = 0; type < ARRAY_SIZE(extra_event); type++) {
377 		if (ev->type == extra_event[type].event)
378 			return extra_event[type].decode(dev, buf, count, ev);
379 	}
380 	return -ENOENT;
381 
382       __found:
383 	if (type >= ST_SPECIAL)
384 		cmd = 0xf0 + (type - ST_SPECIAL);
385 	else
386 		/* data.note.channel and data.control.channel is identical */
387 		cmd = 0x80 | (type << 4) | (ev->data.note.channel & 0x0f);
388 
389 
390 	if (cmd == MIDI_CMD_COMMON_SYSEX) {
391 		snd_midi_event_reset_decode(dev);
392 		return snd_seq_expand_var_event(ev, count, buf, 1, 0);
393 	} else {
394 		int qlen;
395 		unsigned char xbuf[4];
396 		unsigned long flags;
397 
398 		spin_lock_irqsave(&dev->lock, flags);
399 		if ((cmd & 0xf0) == 0xf0 || dev->lastcmd != cmd || dev->nostat) {
400 			dev->lastcmd = cmd;
401 			spin_unlock_irqrestore(&dev->lock, flags);
402 			xbuf[0] = cmd;
403 			if (status_event[type].decode)
404 				status_event[type].decode(ev, xbuf + 1);
405 			qlen = status_event[type].qlen + 1;
406 		} else {
407 			spin_unlock_irqrestore(&dev->lock, flags);
408 			if (status_event[type].decode)
409 				status_event[type].decode(ev, xbuf + 0);
410 			qlen = status_event[type].qlen;
411 		}
412 		if (count < qlen)
413 			return -ENOMEM;
414 		memcpy(buf, xbuf, qlen);
415 		return qlen;
416 	}
417 }
418 EXPORT_SYMBOL(snd_midi_event_decode);
419 
420 
421 /* decode note event */
422 static void note_decode(struct snd_seq_event *ev, unsigned char *buf)
423 {
424 	buf[0] = ev->data.note.note & 0x7f;
425 	buf[1] = ev->data.note.velocity & 0x7f;
426 }
427 
428 /* decode one parameter controls */
429 static void one_param_decode(struct snd_seq_event *ev, unsigned char *buf)
430 {
431 	buf[0] = ev->data.control.value & 0x7f;
432 }
433 
434 /* decode pitch wheel change */
435 static void pitchbend_decode(struct snd_seq_event *ev, unsigned char *buf)
436 {
437 	int value = ev->data.control.value + 8192;
438 	buf[0] = value & 0x7f;
439 	buf[1] = (value >> 7) & 0x7f;
440 }
441 
442 /* decode midi control change */
443 static void two_param_decode(struct snd_seq_event *ev, unsigned char *buf)
444 {
445 	buf[0] = ev->data.control.param & 0x7f;
446 	buf[1] = ev->data.control.value & 0x7f;
447 }
448 
449 /* decode song position */
450 static void songpos_decode(struct snd_seq_event *ev, unsigned char *buf)
451 {
452 	buf[0] = ev->data.control.value & 0x7f;
453 	buf[1] = (ev->data.control.value >> 7) & 0x7f;
454 }
455 
456 /* decode 14bit control */
457 static int extra_decode_ctrl14(struct snd_midi_event *dev, unsigned char *buf,
458 			       int count, struct snd_seq_event *ev)
459 {
460 	unsigned char cmd;
461 	int idx = 0;
462 
463 	cmd = MIDI_CMD_CONTROL|(ev->data.control.channel & 0x0f);
464 	if (ev->data.control.param < 0x20) {
465 		if (count < 4)
466 			return -ENOMEM;
467 		if (dev->nostat && count < 6)
468 			return -ENOMEM;
469 		if (cmd != dev->lastcmd || dev->nostat) {
470 			if (count < 5)
471 				return -ENOMEM;
472 			buf[idx++] = dev->lastcmd = cmd;
473 		}
474 		buf[idx++] = ev->data.control.param;
475 		buf[idx++] = (ev->data.control.value >> 7) & 0x7f;
476 		if (dev->nostat)
477 			buf[idx++] = cmd;
478 		buf[idx++] = ev->data.control.param + 0x20;
479 		buf[idx++] = ev->data.control.value & 0x7f;
480 	} else {
481 		if (count < 2)
482 			return -ENOMEM;
483 		if (cmd != dev->lastcmd || dev->nostat) {
484 			if (count < 3)
485 				return -ENOMEM;
486 			buf[idx++] = dev->lastcmd = cmd;
487 		}
488 		buf[idx++] = ev->data.control.param & 0x7f;
489 		buf[idx++] = ev->data.control.value & 0x7f;
490 	}
491 	return idx;
492 }
493 
494 /* decode reg/nonreg param */
495 static int extra_decode_xrpn(struct snd_midi_event *dev, unsigned char *buf,
496 			     int count, struct snd_seq_event *ev)
497 {
498 	unsigned char cmd;
499 	char *cbytes;
500 	static char cbytes_nrpn[4] = { MIDI_CTL_NONREG_PARM_NUM_MSB,
501 				       MIDI_CTL_NONREG_PARM_NUM_LSB,
502 				       MIDI_CTL_MSB_DATA_ENTRY,
503 				       MIDI_CTL_LSB_DATA_ENTRY };
504 	static char cbytes_rpn[4] =  { MIDI_CTL_REGIST_PARM_NUM_MSB,
505 				       MIDI_CTL_REGIST_PARM_NUM_LSB,
506 				       MIDI_CTL_MSB_DATA_ENTRY,
507 				       MIDI_CTL_LSB_DATA_ENTRY };
508 	unsigned char bytes[4];
509 	int idx = 0, i;
510 
511 	if (count < 8)
512 		return -ENOMEM;
513 	if (dev->nostat && count < 12)
514 		return -ENOMEM;
515 	cmd = MIDI_CMD_CONTROL|(ev->data.control.channel & 0x0f);
516 	bytes[0] = (ev->data.control.param & 0x3f80) >> 7;
517 	bytes[1] = ev->data.control.param & 0x007f;
518 	bytes[2] = (ev->data.control.value & 0x3f80) >> 7;
519 	bytes[3] = ev->data.control.value & 0x007f;
520 	if (cmd != dev->lastcmd && !dev->nostat) {
521 		if (count < 9)
522 			return -ENOMEM;
523 		buf[idx++] = dev->lastcmd = cmd;
524 	}
525 	cbytes = ev->type == SNDRV_SEQ_EVENT_NONREGPARAM ? cbytes_nrpn : cbytes_rpn;
526 	for (i = 0; i < 4; i++) {
527 		if (dev->nostat)
528 			buf[idx++] = dev->lastcmd = cmd;
529 		buf[idx++] = cbytes[i];
530 		buf[idx++] = bytes[i];
531 	}
532 	return idx;
533 }
534 
535 static int __init alsa_seq_midi_event_init(void)
536 {
537 	return 0;
538 }
539 
540 static void __exit alsa_seq_midi_event_exit(void)
541 {
542 }
543 
544 module_init(alsa_seq_midi_event_init)
545 module_exit(alsa_seq_midi_event_exit)
546