seq_midi_event.c

  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(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(dev->buf);
130		kfree(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)(&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)(&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)(&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(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}
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}