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 
snd_midi_event_new(int bufsize,struct snd_midi_event ** rdev)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 
snd_midi_event_free(struct snd_midi_event * dev)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  */
reset_encode(struct snd_midi_event * dev)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 
snd_midi_event_reset_encode(struct snd_midi_event * dev)145 void snd_midi_event_reset_encode(struct snd_midi_event *dev)
146 {
147 	unsigned long flags;
148 
149 	spin_lock_irqsave(&dev->lock, flags);
150 	reset_encode(dev);
151 	spin_unlock_irqrestore(&dev->lock, flags);
152 }
153 EXPORT_SYMBOL(snd_midi_event_reset_encode);
154 
snd_midi_event_reset_decode(struct snd_midi_event * dev)155 void snd_midi_event_reset_decode(struct snd_midi_event *dev)
156 {
157 	unsigned long flags;
158 
159 	spin_lock_irqsave(&dev->lock, flags);
160 	dev->lastcmd = 0xff;
161 	spin_unlock_irqrestore(&dev->lock, flags);
162 }
163 EXPORT_SYMBOL(snd_midi_event_reset_decode);
164 
snd_midi_event_no_status(struct snd_midi_event * dev,int on)165 void snd_midi_event_no_status(struct snd_midi_event *dev, int on)
166 {
167 	dev->nostat = on ? 1 : 0;
168 }
169 EXPORT_SYMBOL(snd_midi_event_no_status);
170 
171 /*
172  *  read one byte and encode to sequencer event:
173  *  return true if MIDI bytes are encoded to an event
174  *         false data is not finished
175  */
snd_midi_event_encode_byte(struct snd_midi_event * dev,unsigned char c,struct snd_seq_event * ev)176 bool snd_midi_event_encode_byte(struct snd_midi_event *dev, unsigned char c,
177 				struct snd_seq_event *ev)
178 {
179 	bool rc = false;
180 	unsigned long flags;
181 
182 	if (c >= MIDI_CMD_COMMON_CLOCK) {
183 		/* real-time event */
184 		ev->type = status_event[ST_SPECIAL + c - 0xf0].event;
185 		ev->flags &= ~SNDRV_SEQ_EVENT_LENGTH_MASK;
186 		ev->flags |= SNDRV_SEQ_EVENT_LENGTH_FIXED;
187 		return ev->type != SNDRV_SEQ_EVENT_NONE;
188 	}
189 
190 	spin_lock_irqsave(&dev->lock, flags);
191 	if ((c & 0x80) &&
192 	    (c != MIDI_CMD_COMMON_SYSEX_END || dev->type != ST_SYSEX)) {
193 		/* new command */
194 		dev->buf[0] = c;
195 		if ((c & 0xf0) == 0xf0) /* system messages */
196 			dev->type = (c & 0x0f) + ST_SPECIAL;
197 		else
198 			dev->type = (c >> 4) & 0x07;
199 		dev->read = 1;
200 		dev->qlen = status_event[dev->type].qlen;
201 	} else {
202 		if (dev->qlen > 0) {
203 			/* rest of command */
204 			dev->buf[dev->read++] = c;
205 			if (dev->type != ST_SYSEX)
206 				dev->qlen--;
207 		} else {
208 			/* running status */
209 			dev->buf[1] = c;
210 			dev->qlen = status_event[dev->type].qlen - 1;
211 			dev->read = 2;
212 		}
213 	}
214 	if (dev->qlen == 0) {
215 		ev->type = status_event[dev->type].event;
216 		ev->flags &= ~SNDRV_SEQ_EVENT_LENGTH_MASK;
217 		ev->flags |= SNDRV_SEQ_EVENT_LENGTH_FIXED;
218 		if (status_event[dev->type].encode) /* set data values */
219 			status_event[dev->type].encode(dev, ev);
220 		if (dev->type >= ST_SPECIAL)
221 			dev->type = ST_INVALID;
222 		rc = true;
223 	} else 	if (dev->type == ST_SYSEX) {
224 		if (c == MIDI_CMD_COMMON_SYSEX_END ||
225 		    dev->read >= dev->bufsize) {
226 			ev->flags &= ~SNDRV_SEQ_EVENT_LENGTH_MASK;
227 			ev->flags |= SNDRV_SEQ_EVENT_LENGTH_VARIABLE;
228 			ev->type = SNDRV_SEQ_EVENT_SYSEX;
229 			ev->data.ext.len = dev->read;
230 			ev->data.ext.ptr = dev->buf;
231 			if (c != MIDI_CMD_COMMON_SYSEX_END)
232 				dev->read = 0; /* continue to parse */
233 			else
234 				reset_encode(dev); /* all parsed */
235 			rc = true;
236 		}
237 	}
238 
239 	spin_unlock_irqrestore(&dev->lock, flags);
240 	return rc;
241 }
242 EXPORT_SYMBOL(snd_midi_event_encode_byte);
243 
244 /* encode note event */
note_event(struct snd_midi_event * dev,struct snd_seq_event * ev)245 static void note_event(struct snd_midi_event *dev, struct snd_seq_event *ev)
246 {
247 	ev->data.note.channel = dev->buf[0] & 0x0f;
248 	ev->data.note.note = dev->buf[1];
249 	ev->data.note.velocity = dev->buf[2];
250 }
251 
252 /* encode one parameter controls */
one_param_ctrl_event(struct snd_midi_event * dev,struct snd_seq_event * ev)253 static void one_param_ctrl_event(struct snd_midi_event *dev, struct snd_seq_event *ev)
254 {
255 	ev->data.control.channel = dev->buf[0] & 0x0f;
256 	ev->data.control.value = dev->buf[1];
257 }
258 
259 /* encode pitch wheel change */
pitchbend_ctrl_event(struct snd_midi_event * dev,struct snd_seq_event * ev)260 static void pitchbend_ctrl_event(struct snd_midi_event *dev, struct snd_seq_event *ev)
261 {
262 	ev->data.control.channel = dev->buf[0] & 0x0f;
263 	ev->data.control.value = (int)dev->buf[2] * 128 + (int)dev->buf[1] - 8192;
264 }
265 
266 /* encode midi control change */
two_param_ctrl_event(struct snd_midi_event * dev,struct snd_seq_event * ev)267 static void two_param_ctrl_event(struct snd_midi_event *dev, struct snd_seq_event *ev)
268 {
269 	ev->data.control.channel = dev->buf[0] & 0x0f;
270 	ev->data.control.param = dev->buf[1];
271 	ev->data.control.value = dev->buf[2];
272 }
273 
274 /* encode one parameter value*/
one_param_event(struct snd_midi_event * dev,struct snd_seq_event * ev)275 static void one_param_event(struct snd_midi_event *dev, struct snd_seq_event *ev)
276 {
277 	ev->data.control.value = dev->buf[1];
278 }
279 
280 /* encode song position */
songpos_event(struct snd_midi_event * dev,struct snd_seq_event * ev)281 static void songpos_event(struct snd_midi_event *dev, struct snd_seq_event *ev)
282 {
283 	ev->data.control.value = (int)dev->buf[2] * 128 + (int)dev->buf[1];
284 }
285 
286 /*
287  * decode from a sequencer event to midi bytes
288  * return the size of decoded midi events
289  */
snd_midi_event_decode(struct snd_midi_event * dev,unsigned char * buf,long count,struct snd_seq_event * ev)290 long snd_midi_event_decode(struct snd_midi_event *dev, unsigned char *buf, long count,
291 			   struct snd_seq_event *ev)
292 {
293 	unsigned int cmd, type;
294 
295 	if (ev->type == SNDRV_SEQ_EVENT_NONE)
296 		return -ENOENT;
297 
298 	for (type = 0; type < ARRAY_SIZE(status_event); type++) {
299 		if (ev->type == status_event[type].event)
300 			goto __found;
301 	}
302 	for (type = 0; type < ARRAY_SIZE(extra_event); type++) {
303 		if (ev->type == extra_event[type].event)
304 			return extra_event[type].decode(dev, buf, count, ev);
305 	}
306 	return -ENOENT;
307 
308       __found:
309 	if (type >= ST_SPECIAL)
310 		cmd = 0xf0 + (type - ST_SPECIAL);
311 	else
312 		/* data.note.channel and data.control.channel is identical */
313 		cmd = 0x80 | (type << 4) | (ev->data.note.channel & 0x0f);
314 
315 
316 	if (cmd == MIDI_CMD_COMMON_SYSEX) {
317 		snd_midi_event_reset_decode(dev);
318 		return snd_seq_expand_var_event(ev, count, buf, 1, 0);
319 	} else {
320 		int qlen;
321 		unsigned char xbuf[4];
322 		unsigned long flags;
323 
324 		spin_lock_irqsave(&dev->lock, flags);
325 		if ((cmd & 0xf0) == 0xf0 || dev->lastcmd != cmd || dev->nostat) {
326 			dev->lastcmd = cmd;
327 			spin_unlock_irqrestore(&dev->lock, flags);
328 			xbuf[0] = cmd;
329 			if (status_event[type].decode)
330 				status_event[type].decode(ev, xbuf + 1);
331 			qlen = status_event[type].qlen + 1;
332 		} else {
333 			spin_unlock_irqrestore(&dev->lock, flags);
334 			if (status_event[type].decode)
335 				status_event[type].decode(ev, xbuf + 0);
336 			qlen = status_event[type].qlen;
337 		}
338 		if (count < qlen)
339 			return -ENOMEM;
340 		memcpy(buf, xbuf, qlen);
341 		return qlen;
342 	}
343 }
344 EXPORT_SYMBOL(snd_midi_event_decode);
345 
346 
347 /* decode note event */
note_decode(struct snd_seq_event * ev,unsigned char * buf)348 static void note_decode(struct snd_seq_event *ev, unsigned char *buf)
349 {
350 	buf[0] = ev->data.note.note & 0x7f;
351 	buf[1] = ev->data.note.velocity & 0x7f;
352 }
353 
354 /* decode one parameter controls */
one_param_decode(struct snd_seq_event * ev,unsigned char * buf)355 static void one_param_decode(struct snd_seq_event *ev, unsigned char *buf)
356 {
357 	buf[0] = ev->data.control.value & 0x7f;
358 }
359 
360 /* decode pitch wheel change */
pitchbend_decode(struct snd_seq_event * ev,unsigned char * buf)361 static void pitchbend_decode(struct snd_seq_event *ev, unsigned char *buf)
362 {
363 	int value = ev->data.control.value + 8192;
364 	buf[0] = value & 0x7f;
365 	buf[1] = (value >> 7) & 0x7f;
366 }
367 
368 /* decode midi control change */
two_param_decode(struct snd_seq_event * ev,unsigned char * buf)369 static void two_param_decode(struct snd_seq_event *ev, unsigned char *buf)
370 {
371 	buf[0] = ev->data.control.param & 0x7f;
372 	buf[1] = ev->data.control.value & 0x7f;
373 }
374 
375 /* decode song position */
songpos_decode(struct snd_seq_event * ev,unsigned char * buf)376 static void songpos_decode(struct snd_seq_event *ev, unsigned char *buf)
377 {
378 	buf[0] = ev->data.control.value & 0x7f;
379 	buf[1] = (ev->data.control.value >> 7) & 0x7f;
380 }
381 
382 /* decode 14bit control */
extra_decode_ctrl14(struct snd_midi_event * dev,unsigned char * buf,int count,struct snd_seq_event * ev)383 static int extra_decode_ctrl14(struct snd_midi_event *dev, unsigned char *buf,
384 			       int count, struct snd_seq_event *ev)
385 {
386 	unsigned char cmd;
387 	int idx = 0;
388 
389 	cmd = MIDI_CMD_CONTROL|(ev->data.control.channel & 0x0f);
390 	if (ev->data.control.param < 0x20) {
391 		if (count < 4)
392 			return -ENOMEM;
393 		if (dev->nostat && count < 6)
394 			return -ENOMEM;
395 		if (cmd != dev->lastcmd || dev->nostat) {
396 			if (count < 5)
397 				return -ENOMEM;
398 			buf[idx++] = dev->lastcmd = cmd;
399 		}
400 		buf[idx++] = ev->data.control.param;
401 		buf[idx++] = (ev->data.control.value >> 7) & 0x7f;
402 		if (dev->nostat)
403 			buf[idx++] = cmd;
404 		buf[idx++] = ev->data.control.param + 0x20;
405 		buf[idx++] = ev->data.control.value & 0x7f;
406 	} else {
407 		if (count < 2)
408 			return -ENOMEM;
409 		if (cmd != dev->lastcmd || dev->nostat) {
410 			if (count < 3)
411 				return -ENOMEM;
412 			buf[idx++] = dev->lastcmd = cmd;
413 		}
414 		buf[idx++] = ev->data.control.param & 0x7f;
415 		buf[idx++] = ev->data.control.value & 0x7f;
416 	}
417 	return idx;
418 }
419 
420 /* decode reg/nonreg param */
extra_decode_xrpn(struct snd_midi_event * dev,unsigned char * buf,int count,struct snd_seq_event * ev)421 static int extra_decode_xrpn(struct snd_midi_event *dev, unsigned char *buf,
422 			     int count, struct snd_seq_event *ev)
423 {
424 	unsigned char cmd;
425 	const char *cbytes;
426 	static const char cbytes_nrpn[4] = { MIDI_CTL_NONREG_PARM_NUM_MSB,
427 				       MIDI_CTL_NONREG_PARM_NUM_LSB,
428 				       MIDI_CTL_MSB_DATA_ENTRY,
429 				       MIDI_CTL_LSB_DATA_ENTRY };
430 	static const char cbytes_rpn[4] =  { MIDI_CTL_REGIST_PARM_NUM_MSB,
431 				       MIDI_CTL_REGIST_PARM_NUM_LSB,
432 				       MIDI_CTL_MSB_DATA_ENTRY,
433 				       MIDI_CTL_LSB_DATA_ENTRY };
434 	unsigned char bytes[4];
435 	int idx = 0, i;
436 
437 	if (count < 8)
438 		return -ENOMEM;
439 	if (dev->nostat && count < 12)
440 		return -ENOMEM;
441 	cmd = MIDI_CMD_CONTROL|(ev->data.control.channel & 0x0f);
442 	bytes[0] = (ev->data.control.param & 0x3f80) >> 7;
443 	bytes[1] = ev->data.control.param & 0x007f;
444 	bytes[2] = (ev->data.control.value & 0x3f80) >> 7;
445 	bytes[3] = ev->data.control.value & 0x007f;
446 	if (cmd != dev->lastcmd && !dev->nostat) {
447 		if (count < 9)
448 			return -ENOMEM;
449 		buf[idx++] = dev->lastcmd = cmd;
450 	}
451 	cbytes = ev->type == SNDRV_SEQ_EVENT_NONREGPARAM ? cbytes_nrpn : cbytes_rpn;
452 	for (i = 0; i < 4; i++) {
453 		if (dev->nostat)
454 			buf[idx++] = dev->lastcmd = cmd;
455 		buf[idx++] = cbytes[i];
456 		buf[idx++] = bytes[i];
457 	}
458 	return idx;
459 }
460