xref: /linux/sound/core/seq/seq_midi_event.c (revision 1e525507) 
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *  MIDI byte <-> sequencer event coder
4  *
5  *  Copyright (C) 1998,99 Takashi Iwai <tiwai@suse.de>,
6  *                        Jaroslav Kysela <perex@perex.cz>
7  */
8 
9 #include <linux/slab.h>
10 #include <linux/errno.h>
11 #include <linux/string.h>
12 #include <linux/module.h>
13 #include <sound/core.h>
14 #include <sound/seq_kernel.h>
15 #include <sound/seq_midi_event.h>
16 #include <sound/asoundef.h>
17 
18 MODULE_AUTHOR("Takashi Iwai <tiwai@suse.de>, Jaroslav Kysela <perex@perex.cz>");
19 MODULE_DESCRIPTION("MIDI byte <-> sequencer event coder");
20 MODULE_LICENSE("GPL");
21 
22 /* event type, index into status_event[] */
23 /* from 0 to 6 are normal commands (note off, on, etc.) for 0x9?-0xe? */
24 #define ST_INVALID	7
25 #define ST_SPECIAL	8
26 #define ST_SYSEX	ST_SPECIAL
27 /* from 8 to 15 are events for 0xf0-0xf7 */
28 
29 
30 /*
31  * prototypes
32  */
33 static void note_event(struct snd_midi_event *dev, struct snd_seq_event *ev);
34 static void one_param_ctrl_event(struct snd_midi_event *dev, struct snd_seq_event *ev);
35 static void pitchbend_ctrl_event(struct snd_midi_event *dev, struct snd_seq_event *ev);
36 static void two_param_ctrl_event(struct snd_midi_event *dev, struct snd_seq_event *ev);
37 static void one_param_event(struct snd_midi_event *dev, struct snd_seq_event *ev);
38 static void songpos_event(struct snd_midi_event *dev, struct snd_seq_event *ev);
39 static void note_decode(struct snd_seq_event *ev, unsigned char *buf);
40 static void one_param_decode(struct snd_seq_event *ev, unsigned char *buf);
41 static void pitchbend_decode(struct snd_seq_event *ev, unsigned char *buf);
42 static void two_param_decode(struct snd_seq_event *ev, unsigned char *buf);
43 static void songpos_decode(struct snd_seq_event *ev, unsigned char *buf);
44 
45 /*
46  * event list
47  */
48 static struct status_event_list {
49 	int event;
50 	int qlen;
51 	void (*encode)(struct snd_midi_event *dev, struct snd_seq_event *ev);
52 	void (*decode)(struct snd_seq_event *ev, unsigned char *buf);
53 } status_event[] = {
54 	/* 0x80 - 0xef */
55 	{SNDRV_SEQ_EVENT_NOTEOFF,	 2, note_event, note_decode},
56 	{SNDRV_SEQ_EVENT_NOTEON,	 2, note_event, note_decode},
57 	{SNDRV_SEQ_EVENT_KEYPRESS,	 2, note_event, note_decode},
58 	{SNDRV_SEQ_EVENT_CONTROLLER,	 2, two_param_ctrl_event, two_param_decode},
59 	{SNDRV_SEQ_EVENT_PGMCHANGE,	 1, one_param_ctrl_event, one_param_decode},
60 	{SNDRV_SEQ_EVENT_CHANPRESS,	 1, one_param_ctrl_event, one_param_decode},
61 	{SNDRV_SEQ_EVENT_PITCHBEND,	 2, pitchbend_ctrl_event, pitchbend_decode},
62 	/* invalid */
63 	{SNDRV_SEQ_EVENT_NONE,		-1, NULL, NULL},
64 	/* 0xf0 - 0xff */
65 	{SNDRV_SEQ_EVENT_SYSEX,		 1, NULL, NULL}, /* sysex: 0xf0 */
66 	{SNDRV_SEQ_EVENT_QFRAME,	 1, one_param_event, one_param_decode}, /* 0xf1 */
67 	{SNDRV_SEQ_EVENT_SONGPOS,	 2, songpos_event, songpos_decode}, /* 0xf2 */
68 	{SNDRV_SEQ_EVENT_SONGSEL,	 1, one_param_event, one_param_decode}, /* 0xf3 */
69 	{SNDRV_SEQ_EVENT_NONE,		-1, NULL, NULL}, /* 0xf4 */
70 	{SNDRV_SEQ_EVENT_NONE,		-1, NULL, NULL}, /* 0xf5 */
71 	{SNDRV_SEQ_EVENT_TUNE_REQUEST,	 0, NULL, NULL}, /* 0xf6 */
72 	{SNDRV_SEQ_EVENT_NONE,		-1, NULL, NULL}, /* 0xf7 */
73 	{SNDRV_SEQ_EVENT_CLOCK,		 0, NULL, NULL}, /* 0xf8 */
74 	{SNDRV_SEQ_EVENT_NONE,		-1, NULL, NULL}, /* 0xf9 */
75 	{SNDRV_SEQ_EVENT_START,		 0, NULL, NULL}, /* 0xfa */
76 	{SNDRV_SEQ_EVENT_CONTINUE,	 0, NULL, NULL}, /* 0xfb */
77 	{SNDRV_SEQ_EVENT_STOP, 		 0, NULL, NULL}, /* 0xfc */
78 	{SNDRV_SEQ_EVENT_NONE, 		-1, NULL, NULL}, /* 0xfd */
79 	{SNDRV_SEQ_EVENT_SENSING, 	 0, NULL, NULL}, /* 0xfe */
80 	{SNDRV_SEQ_EVENT_RESET, 	 0, NULL, NULL}, /* 0xff */
81 };
82 
83 static int extra_decode_ctrl14(struct snd_midi_event *dev, unsigned char *buf, int len,
84 			       struct snd_seq_event *ev);
85 static int extra_decode_xrpn(struct snd_midi_event *dev, unsigned char *buf, int count,
86 			     struct snd_seq_event *ev);
87 
88 static struct extra_event_list {
89 	int event;
90 	int (*decode)(struct snd_midi_event *dev, unsigned char *buf, int len,
91 		      struct snd_seq_event *ev);
92 } extra_event[] = {
93 	{SNDRV_SEQ_EVENT_CONTROL14, extra_decode_ctrl14},
94 	{SNDRV_SEQ_EVENT_NONREGPARAM, extra_decode_xrpn},
95 	{SNDRV_SEQ_EVENT_REGPARAM, extra_decode_xrpn},
96 };
97 
98 /*
99  *  new/delete record
100  */
101 
102 int snd_midi_event_new(int bufsize, struct snd_midi_event **rdev)
103 {
104 	struct snd_midi_event *dev;
105 
106 	*rdev = NULL;
107 	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
108 	if (dev == NULL)
109 		return -ENOMEM;
110 	if (bufsize > 0) {
111 		dev->buf = kmalloc(bufsize, GFP_KERNEL);
112 		if (dev->buf == NULL) {
113 			kfree(dev);
114 			return -ENOMEM;
115 		}
116 	}
117 	dev->bufsize = bufsize;
118 	dev->lastcmd = 0xff;
119 	dev->type = ST_INVALID;
120 	spin_lock_init(&dev->lock);
121 	*rdev = dev;
122 	return 0;
123 }
124 EXPORT_SYMBOL(snd_midi_event_new);
125 
126 void snd_midi_event_free(struct snd_midi_event *dev)
127 {
128 	if (dev != NULL) {
129 		kfree(dev->buf);
130 		kfree(dev);
131 	}
132 }
133 EXPORT_SYMBOL(snd_midi_event_free);
134 
135 /*
136  * initialize record
137  */
138 static inline void reset_encode(struct snd_midi_event *dev)
139 {
140 	dev->read = 0;
141 	dev->qlen = 0;
142 	dev->type = ST_INVALID;
143 }
144 
145 void snd_midi_event_reset_encode(struct snd_midi_event *dev)
146 {
147 	guard(spinlock_irqsave)(&dev->lock);
148 	reset_encode(dev);
149 }
150 EXPORT_SYMBOL(snd_midi_event_reset_encode);
151 
152 void snd_midi_event_reset_decode(struct snd_midi_event *dev)
153 {
154 	guard(spinlock_irqsave)(&dev->lock);
155 	dev->lastcmd = 0xff;
156 }
157 EXPORT_SYMBOL(snd_midi_event_reset_decode);
158 
159 void snd_midi_event_no_status(struct snd_midi_event *dev, int on)
160 {
161 	dev->nostat = on ? 1 : 0;
162 }
163 EXPORT_SYMBOL(snd_midi_event_no_status);
164 
165 /*
166  *  read one byte and encode to sequencer event:
167  *  return true if MIDI bytes are encoded to an event
168  *         false data is not finished
169  */
170 bool snd_midi_event_encode_byte(struct snd_midi_event *dev, unsigned char c,
171 				struct snd_seq_event *ev)
172 {
173 	bool rc = false;
174 
175 	if (c >= MIDI_CMD_COMMON_CLOCK) {
176 		/* real-time event */
177 		ev->type = status_event[ST_SPECIAL + c - 0xf0].event;
178 		ev->flags &= ~SNDRV_SEQ_EVENT_LENGTH_MASK;
179 		ev->flags |= SNDRV_SEQ_EVENT_LENGTH_FIXED;
180 		return ev->type != SNDRV_SEQ_EVENT_NONE;
181 	}
182 
183 	guard(spinlock_irqsave)(&dev->lock);
184 	if ((c & 0x80) &&
185 	    (c != MIDI_CMD_COMMON_SYSEX_END || dev->type != ST_SYSEX)) {
186 		/* new command */
187 		dev->buf[0] = c;
188 		if ((c & 0xf0) == 0xf0) /* system messages */
189 			dev->type = (c & 0x0f) + ST_SPECIAL;
190 		else
191 			dev->type = (c >> 4) & 0x07;
192 		dev->read = 1;
193 		dev->qlen = status_event[dev->type].qlen;
194 	} else {
195 		if (dev->qlen > 0) {
196 			/* rest of command */
197 			dev->buf[dev->read++] = c;
198 			if (dev->type != ST_SYSEX)
199 				dev->qlen--;
200 		} else {
201 			/* running status */
202 			dev->buf[1] = c;
203 			dev->qlen = status_event[dev->type].qlen - 1;
204 			dev->read = 2;
205 		}
206 	}
207 	if (dev->qlen == 0) {
208 		ev->type = status_event[dev->type].event;
209 		ev->flags &= ~SNDRV_SEQ_EVENT_LENGTH_MASK;
210 		ev->flags |= SNDRV_SEQ_EVENT_LENGTH_FIXED;
211 		if (status_event[dev->type].encode) /* set data values */
212 			status_event[dev->type].encode(dev, ev);
213 		if (dev->type >= ST_SPECIAL)
214 			dev->type = ST_INVALID;
215 		rc = true;
216 	} else 	if (dev->type == ST_SYSEX) {
217 		if (c == MIDI_CMD_COMMON_SYSEX_END ||
218 		    dev->read >= dev->bufsize) {
219 			ev->flags &= ~SNDRV_SEQ_EVENT_LENGTH_MASK;
220 			ev->flags |= SNDRV_SEQ_EVENT_LENGTH_VARIABLE;
221 			ev->type = SNDRV_SEQ_EVENT_SYSEX;
222 			ev->data.ext.len = dev->read;
223 			ev->data.ext.ptr = dev->buf;
224 			if (c != MIDI_CMD_COMMON_SYSEX_END)
225 				dev->read = 0; /* continue to parse */
226 			else
227 				reset_encode(dev); /* all parsed */
228 			rc = true;
229 		}
230 	}
231 
232 	return rc;
233 }
234 EXPORT_SYMBOL(snd_midi_event_encode_byte);
235 
236 /* encode note event */
237 static void note_event(struct snd_midi_event *dev, struct snd_seq_event *ev)
238 {
239 	ev->data.note.channel = dev->buf[0] & 0x0f;
240 	ev->data.note.note = dev->buf[1];
241 	ev->data.note.velocity = dev->buf[2];
242 }
243 
244 /* encode one parameter controls */
245 static void one_param_ctrl_event(struct snd_midi_event *dev, struct snd_seq_event *ev)
246 {
247 	ev->data.control.channel = dev->buf[0] & 0x0f;
248 	ev->data.control.value = dev->buf[1];
249 }
250 
251 /* encode pitch wheel change */
252 static void pitchbend_ctrl_event(struct snd_midi_event *dev, struct snd_seq_event *ev)
253 {
254 	ev->data.control.channel = dev->buf[0] & 0x0f;
255 	ev->data.control.value = (int)dev->buf[2] * 128 + (int)dev->buf[1] - 8192;
256 }
257 
258 /* encode midi control change */
259 static void two_param_ctrl_event(struct snd_midi_event *dev, struct snd_seq_event *ev)
260 {
261 	ev->data.control.channel = dev->buf[0] & 0x0f;
262 	ev->data.control.param = dev->buf[1];
263 	ev->data.control.value = dev->buf[2];
264 }
265 
266 /* encode one parameter value*/
267 static void one_param_event(struct snd_midi_event *dev, struct snd_seq_event *ev)
268 {
269 	ev->data.control.value = dev->buf[1];
270 }
271 
272 /* encode song position */
273 static void songpos_event(struct snd_midi_event *dev, struct snd_seq_event *ev)
274 {
275 	ev->data.control.value = (int)dev->buf[2] * 128 + (int)dev->buf[1];
276 }
277 
278 /*
279  * decode from a sequencer event to midi bytes
280  * return the size of decoded midi events
281  */
282 long snd_midi_event_decode(struct snd_midi_event *dev, unsigned char *buf, long count,
283 			   struct snd_seq_event *ev)
284 {
285 	unsigned int cmd, type;
286 
287 	if (ev->type == SNDRV_SEQ_EVENT_NONE)
288 		return -ENOENT;
289 
290 	for (type = 0; type < ARRAY_SIZE(status_event); type++) {
291 		if (ev->type == status_event[type].event)
292 			goto __found;
293 	}
294 	for (type = 0; type < ARRAY_SIZE(extra_event); type++) {
295 		if (ev->type == extra_event[type].event)
296 			return extra_event[type].decode(dev, buf, count, ev);
297 	}
298 	return -ENOENT;
299 
300       __found:
301 	if (type >= ST_SPECIAL)
302 		cmd = 0xf0 + (type - ST_SPECIAL);
303 	else
304 		/* data.note.channel and data.control.channel is identical */
305 		cmd = 0x80 | (type << 4) | (ev->data.note.channel & 0x0f);
306 
307 
308 	if (cmd == MIDI_CMD_COMMON_SYSEX) {
309 		snd_midi_event_reset_decode(dev);
310 		return snd_seq_expand_var_event(ev, count, buf, 1, 0);
311 	} else {
312 		int qlen;
313 		unsigned char xbuf[4];
314 		unsigned long flags;
315 
316 		spin_lock_irqsave(&dev->lock, flags);
317 		if ((cmd & 0xf0) == 0xf0 || dev->lastcmd != cmd || dev->nostat) {
318 			dev->lastcmd = cmd;
319 			spin_unlock_irqrestore(&dev->lock, flags);
320 			xbuf[0] = cmd;
321 			if (status_event[type].decode)
322 				status_event[type].decode(ev, xbuf + 1);
323 			qlen = status_event[type].qlen + 1;
324 		} else {
325 			spin_unlock_irqrestore(&dev->lock, flags);
326 			if (status_event[type].decode)
327 				status_event[type].decode(ev, xbuf + 0);
328 			qlen = status_event[type].qlen;
329 		}
330 		if (count < qlen)
331 			return -ENOMEM;
332 		memcpy(buf, xbuf, qlen);
333 		return qlen;
334 	}
335 }
336 EXPORT_SYMBOL(snd_midi_event_decode);
337 
338 
339 /* decode note event */
340 static void note_decode(struct snd_seq_event *ev, unsigned char *buf)
341 {
342 	buf[0] = ev->data.note.note & 0x7f;
343 	buf[1] = ev->data.note.velocity & 0x7f;
344 }
345 
346 /* decode one parameter controls */
347 static void one_param_decode(struct snd_seq_event *ev, unsigned char *buf)
348 {
349 	buf[0] = ev->data.control.value & 0x7f;
350 }
351 
352 /* decode pitch wheel change */
353 static void pitchbend_decode(struct snd_seq_event *ev, unsigned char *buf)
354 {
355 	int value = ev->data.control.value + 8192;
356 	buf[0] = value & 0x7f;
357 	buf[1] = (value >> 7) & 0x7f;
358 }
359 
360 /* decode midi control change */
361 static void two_param_decode(struct snd_seq_event *ev, unsigned char *buf)
362 {
363 	buf[0] = ev->data.control.param & 0x7f;
364 	buf[1] = ev->data.control.value & 0x7f;
365 }
366 
367 /* decode song position */
368 static void songpos_decode(struct snd_seq_event *ev, unsigned char *buf)
369 {
370 	buf[0] = ev->data.control.value & 0x7f;
371 	buf[1] = (ev->data.control.value >> 7) & 0x7f;
372 }
373 
374 /* decode 14bit control */
375 static int extra_decode_ctrl14(struct snd_midi_event *dev, unsigned char *buf,
376 			       int count, struct snd_seq_event *ev)
377 {
378 	unsigned char cmd;
379 	int idx = 0;
380 
381 	cmd = MIDI_CMD_CONTROL|(ev->data.control.channel & 0x0f);
382 	if (ev->data.control.param < 0x20) {
383 		if (count < 4)
384 			return -ENOMEM;
385 		if (dev->nostat && count < 6)
386 			return -ENOMEM;
387 		if (cmd != dev->lastcmd || dev->nostat) {
388 			if (count < 5)
389 				return -ENOMEM;
390 			buf[idx++] = dev->lastcmd = cmd;
391 		}
392 		buf[idx++] = ev->data.control.param;
393 		buf[idx++] = (ev->data.control.value >> 7) & 0x7f;
394 		if (dev->nostat)
395 			buf[idx++] = cmd;
396 		buf[idx++] = ev->data.control.param + 0x20;
397 		buf[idx++] = ev->data.control.value & 0x7f;
398 	} else {
399 		if (count < 2)
400 			return -ENOMEM;
401 		if (cmd != dev->lastcmd || dev->nostat) {
402 			if (count < 3)
403 				return -ENOMEM;
404 			buf[idx++] = dev->lastcmd = cmd;
405 		}
406 		buf[idx++] = ev->data.control.param & 0x7f;
407 		buf[idx++] = ev->data.control.value & 0x7f;
408 	}
409 	return idx;
410 }
411 
412 /* decode reg/nonreg param */
413 static int extra_decode_xrpn(struct snd_midi_event *dev, unsigned char *buf,
414 			     int count, struct snd_seq_event *ev)
415 {
416 	unsigned char cmd;
417 	const char *cbytes;
418 	static const char cbytes_nrpn[4] = { MIDI_CTL_NONREG_PARM_NUM_MSB,
419 				       MIDI_CTL_NONREG_PARM_NUM_LSB,
420 				       MIDI_CTL_MSB_DATA_ENTRY,
421 				       MIDI_CTL_LSB_DATA_ENTRY };
422 	static const char cbytes_rpn[4] =  { MIDI_CTL_REGIST_PARM_NUM_MSB,
423 				       MIDI_CTL_REGIST_PARM_NUM_LSB,
424 				       MIDI_CTL_MSB_DATA_ENTRY,
425 				       MIDI_CTL_LSB_DATA_ENTRY };
426 	unsigned char bytes[4];
427 	int idx = 0, i;
428 
429 	if (count < 8)
430 		return -ENOMEM;
431 	if (dev->nostat && count < 12)
432 		return -ENOMEM;
433 	cmd = MIDI_CMD_CONTROL|(ev->data.control.channel & 0x0f);
434 	bytes[0] = (ev->data.control.param & 0x3f80) >> 7;
435 	bytes[1] = ev->data.control.param & 0x007f;
436 	bytes[2] = (ev->data.control.value & 0x3f80) >> 7;
437 	bytes[3] = ev->data.control.value & 0x007f;
438 	if (cmd != dev->lastcmd && !dev->nostat) {
439 		if (count < 9)
440 			return -ENOMEM;
441 		buf[idx++] = dev->lastcmd = cmd;
442 	}
443 	cbytes = ev->type == SNDRV_SEQ_EVENT_NONREGPARAM ? cbytes_nrpn : cbytes_rpn;
444 	for (i = 0; i < 4; i++) {
445 		if (dev->nostat)
446 			buf[idx++] = dev->lastcmd = cmd;
447 		buf[idx++] = cbytes[i];
448 		buf[idx++] = bytes[i];
449 	}
450 	return idx;
451 }
452