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