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
18MODULE_AUTHOR("Takashi Iwai <tiwai@suse.de>, Jaroslav Kysela <perex@perex.cz>");
19MODULE_DESCRIPTION("MIDI byte <-> sequencer event coder");
20MODULE_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 */
33static void note_event(struct snd_midi_event *dev, struct snd_seq_event *ev);
34static void one_param_ctrl_event(struct snd_midi_event *dev, struct snd_seq_event *ev);
35static void pitchbend_ctrl_event(struct snd_midi_event *dev, struct snd_seq_event *ev);
36static void two_param_ctrl_event(struct snd_midi_event *dev, struct snd_seq_event *ev);
37static void one_param_event(struct snd_midi_event *dev, struct snd_seq_event *ev);
38static void songpos_event(struct snd_midi_event *dev, struct snd_seq_event *ev);
39static void note_decode(struct snd_seq_event *ev, unsigned char *buf);
40static void one_param_decode(struct snd_seq_event *ev, unsigned char *buf);
41static void pitchbend_decode(struct snd_seq_event *ev, unsigned char *buf);
42static void two_param_decode(struct snd_seq_event *ev, unsigned char *buf);
43static void songpos_decode(struct snd_seq_event *ev, unsigned char *buf);
44
45/*
46 * event list
47 */
48static 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
83static int extra_decode_ctrl14(struct snd_midi_event *dev, unsigned char *buf, int len,
84 struct snd_seq_event *ev);
85static int extra_decode_xrpn(struct snd_midi_event *dev, unsigned char *buf, int count,
86 struct snd_seq_event *ev);
87
88static 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
102int 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(objp: 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}
124EXPORT_SYMBOL(snd_midi_event_new);
125
126void snd_midi_event_free(struct snd_midi_event *dev)
127{
128 if (dev != NULL) {
129 kfree(objp: dev->buf);
130 kfree(objp: dev);
131 }
132}
133EXPORT_SYMBOL(snd_midi_event_free);
134
135/*
136 * initialize record
137 */
138static 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
145void snd_midi_event_reset_encode(struct snd_midi_event *dev)
146{
147 guard(spinlock_irqsave)(l: &dev->lock);
148 reset_encode(dev);
149}
150EXPORT_SYMBOL(snd_midi_event_reset_encode);
151
152void snd_midi_event_reset_decode(struct snd_midi_event *dev)
153{
154 guard(spinlock_irqsave)(l: &dev->lock);
155 dev->lastcmd = 0xff;
156}
157EXPORT_SYMBOL(snd_midi_event_reset_decode);
158
159void snd_midi_event_no_status(struct snd_midi_event *dev, int on)
160{
161 dev->nostat = on ? 1 : 0;
162}
163EXPORT_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 */
170bool 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)(l: &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}
234EXPORT_SYMBOL(snd_midi_event_encode_byte);
235
236/* encode note event */
237static 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 */
245static 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 */
252static 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 */
259static 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*/
267static 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 */
273static 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 */
282long 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(event: ev, count, buf, in_kernel: 1, size_aligned: 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(lock: &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(lock: &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}
336EXPORT_SYMBOL(snd_midi_event_decode);
337
338
339/* decode note event */
340static 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 */
347static 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 */
353static 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 */
361static 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 */
368static 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 */
375static 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 */
413static 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

source code of linux/sound/core/seq/seq_midi_event.c