xref: /openbmc/linux/sound/core/ump_convert.c (revision 11078e2d)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Helpers for UMP <-> MIDI 1.0 byte stream conversion
4  */
5 
6 #include <linux/module.h>
7 #include <linux/export.h>
8 #include <sound/core.h>
9 #include <sound/asound.h>
10 #include <sound/ump.h>
11 #include <sound/ump_convert.h>
12 
13 /*
14  * Upgrade / downgrade value bits
15  */
16 static u8 downscale_32_to_7bit(u32 src)
17 {
18 	return src >> 25;
19 }
20 
21 static u16 downscale_32_to_14bit(u32 src)
22 {
23 	return src >> 18;
24 }
25 
26 static u8 downscale_16_to_7bit(u16 src)
27 {
28 	return src >> 9;
29 }
30 
31 static u16 upscale_7_to_16bit(u8 src)
32 {
33 	u16 val, repeat;
34 
35 	val = (u16)src << 9;
36 	if (src <= 0x40)
37 		return val;
38 	repeat = src & 0x3f;
39 	return val | (repeat << 3) | (repeat >> 3);
40 }
41 
42 static u32 upscale_7_to_32bit(u8 src)
43 {
44 	u32 val, repeat;
45 
46 	val = src << 25;
47 	if (src <= 0x40)
48 		return val;
49 	repeat = src & 0x3f;
50 	return val | (repeat << 19) | (repeat << 13) |
51 		(repeat << 7) | (repeat << 1) | (repeat >> 5);
52 }
53 
54 static u32 upscale_14_to_32bit(u16 src)
55 {
56 	u32 val, repeat;
57 
58 	val = src << 18;
59 	if (src <= 0x2000)
60 		return val;
61 	repeat = src & 0x1fff;
62 	return val | (repeat << 5) | (repeat >> 8);
63 }
64 
65 /*
66  * UMP -> MIDI 1 byte stream conversion
67  */
68 /* convert a UMP System message to MIDI 1.0 byte stream */
69 static int cvt_ump_system_to_legacy(u32 data, unsigned char *buf)
70 {
71 	buf[0] = ump_message_status_channel(data);
72 	switch (ump_message_status_code(data)) {
73 	case UMP_SYSTEM_STATUS_MIDI_TIME_CODE:
74 	case UMP_SYSTEM_STATUS_SONG_SELECT:
75 		buf[1] = (data >> 8) & 0x7f;
76 		return 2;
77 	case UMP_SYSTEM_STATUS_SONG_POSITION:
78 		buf[1] = (data >> 8) & 0x7f;
79 		buf[2] = data & 0x7f;
80 		return 3;
81 	default:
82 		return 1;
83 	}
84 }
85 
86 /* convert a UMP MIDI 1.0 Channel Voice message to MIDI 1.0 byte stream */
87 static int cvt_ump_midi1_to_legacy(u32 data, unsigned char *buf)
88 {
89 	buf[0] = ump_message_status_channel(data);
90 	buf[1] = (data >> 8) & 0xff;
91 	switch (ump_message_status_code(data)) {
92 	case UMP_MSG_STATUS_PROGRAM:
93 	case UMP_MSG_STATUS_CHANNEL_PRESSURE:
94 		return 2;
95 	default:
96 		buf[2] = data & 0xff;
97 		return 3;
98 	}
99 }
100 
101 /* convert a UMP MIDI 2.0 Channel Voice message to MIDI 1.0 byte stream */
102 static int cvt_ump_midi2_to_legacy(const union snd_ump_midi2_msg *midi2,
103 				   unsigned char *buf)
104 {
105 	unsigned char status = midi2->note.status;
106 	unsigned char channel = midi2->note.channel;
107 	u16 v;
108 
109 	buf[0] = (status << 4) | channel;
110 	switch (status) {
111 	case UMP_MSG_STATUS_NOTE_OFF:
112 	case UMP_MSG_STATUS_NOTE_ON:
113 		buf[1] = midi2->note.note;
114 		buf[2] = downscale_16_to_7bit(midi2->note.velocity);
115 		if (status == UMP_MSG_STATUS_NOTE_ON && !buf[2])
116 			buf[2] = 1;
117 		return 3;
118 	case UMP_MSG_STATUS_POLY_PRESSURE:
119 		buf[1] = midi2->paf.note;
120 		buf[2] = downscale_32_to_7bit(midi2->paf.data);
121 		return 3;
122 	case UMP_MSG_STATUS_CC:
123 		buf[1] = midi2->cc.index;
124 		buf[2] = downscale_32_to_7bit(midi2->cc.data);
125 		return 3;
126 	case UMP_MSG_STATUS_CHANNEL_PRESSURE:
127 		buf[1] = downscale_32_to_7bit(midi2->caf.data);
128 		return 2;
129 	case UMP_MSG_STATUS_PROGRAM:
130 		if (midi2->pg.bank_valid) {
131 			buf[0] = channel | (UMP_MSG_STATUS_CC << 4);
132 			buf[1] = UMP_CC_BANK_SELECT;
133 			buf[2] = midi2->pg.bank_msb;
134 			buf[3] = channel | (UMP_MSG_STATUS_CC << 4);
135 			buf[4] = UMP_CC_BANK_SELECT_LSB;
136 			buf[5] = midi2->pg.bank_lsb;
137 			buf[6] = channel | (UMP_MSG_STATUS_PROGRAM << 4);
138 			buf[7] = midi2->pg.program;
139 			return 8;
140 		}
141 		buf[1] = midi2->pg.program;
142 		return 2;
143 	case UMP_MSG_STATUS_PITCH_BEND:
144 		v = downscale_32_to_14bit(midi2->pb.data);
145 		buf[1] = v & 0x7f;
146 		buf[2] = v >> 7;
147 		return 3;
148 	case UMP_MSG_STATUS_RPN:
149 	case UMP_MSG_STATUS_NRPN:
150 		buf[0] = channel | (UMP_MSG_STATUS_CC << 4);
151 		buf[1] = status == UMP_MSG_STATUS_RPN ? UMP_CC_RPN_MSB : UMP_CC_NRPN_MSB;
152 		buf[2] = midi2->rpn.bank;
153 		buf[3] = buf[0];
154 		buf[4] = status == UMP_MSG_STATUS_RPN ? UMP_CC_RPN_LSB : UMP_CC_NRPN_LSB;
155 		buf[5] = midi2->rpn.index;
156 		buf[6] = buf[0];
157 		buf[7] = UMP_CC_DATA;
158 		v = downscale_32_to_14bit(midi2->rpn.data);
159 		buf[8] = v >> 7;
160 		buf[9] = buf[0];
161 		buf[10] = UMP_CC_DATA_LSB;
162 		buf[11] = v & 0x7f;
163 		return 12;
164 	default:
165 		return 0;
166 	}
167 }
168 
169 /* convert a UMP 7-bit SysEx message to MIDI 1.0 byte stream */
170 static int cvt_ump_sysex7_to_legacy(const u32 *data, unsigned char *buf)
171 {
172 	unsigned char status;
173 	unsigned char bytes;
174 	int size, offset;
175 
176 	status = ump_sysex_message_status(*data);
177 	if (status > UMP_SYSEX_STATUS_END)
178 		return 0; // unsupported, skip
179 	bytes = ump_sysex_message_length(*data);
180 	if (bytes > 6)
181 		return 0; // skip
182 
183 	size = 0;
184 	if (status == UMP_SYSEX_STATUS_SINGLE ||
185 	    status == UMP_SYSEX_STATUS_START) {
186 		buf[0] = UMP_MIDI1_MSG_SYSEX_START;
187 		size = 1;
188 	}
189 
190 	offset = 8;
191 	for (; bytes; bytes--, size++) {
192 		buf[size] = (*data >> offset) & 0x7f;
193 		if (!offset) {
194 			offset = 24;
195 			data++;
196 		} else {
197 			offset -= 8;
198 		}
199 	}
200 
201 	if (status == UMP_SYSEX_STATUS_SINGLE ||
202 	    status == UMP_SYSEX_STATUS_END)
203 		buf[size++] = UMP_MIDI1_MSG_SYSEX_END;
204 
205 	return size;
206 }
207 
208 /**
209  * snd_ump_convert_from_ump - convert from UMP to legacy MIDI
210  * @data: UMP packet
211  * @buf: buffer to store legacy MIDI data
212  * @group_ret: pointer to store the target group
213  *
214  * Convert from a UMP packet @data to MIDI 1.0 bytes at @buf.
215  * The target group is stored at @group_ret.
216  *
217  * The function returns the number of bytes of MIDI 1.0 stream.
218  */
219 int snd_ump_convert_from_ump(const u32 *data,
220 			     unsigned char *buf,
221 			     unsigned char *group_ret)
222 {
223 	*group_ret = ump_message_group(*data);
224 
225 	switch (ump_message_type(*data)) {
226 	case UMP_MSG_TYPE_SYSTEM:
227 		return cvt_ump_system_to_legacy(*data, buf);
228 	case UMP_MSG_TYPE_MIDI1_CHANNEL_VOICE:
229 		return cvt_ump_midi1_to_legacy(*data, buf);
230 	case UMP_MSG_TYPE_MIDI2_CHANNEL_VOICE:
231 		return cvt_ump_midi2_to_legacy((const union snd_ump_midi2_msg *)data,
232 					       buf);
233 	case UMP_MSG_TYPE_DATA:
234 		return cvt_ump_sysex7_to_legacy(data, buf);
235 	}
236 
237 	return 0;
238 }
239 EXPORT_SYMBOL_GPL(snd_ump_convert_from_ump);
240 
241 /*
242  * MIDI 1 byte stream -> UMP conversion
243  */
244 /* convert MIDI 1.0 SysEx to a UMP packet */
245 static int cvt_legacy_sysex_to_ump(struct ump_cvt_to_ump *cvt,
246 				   unsigned char group, u32 *data, bool finish)
247 {
248 	unsigned char status;
249 	bool start = cvt->in_sysex == 1;
250 	int i, offset;
251 
252 	if (start && finish)
253 		status = UMP_SYSEX_STATUS_SINGLE;
254 	else if (start)
255 		status = UMP_SYSEX_STATUS_START;
256 	else if (finish)
257 		status = UMP_SYSEX_STATUS_END;
258 	else
259 		status = UMP_SYSEX_STATUS_CONTINUE;
260 	*data = ump_compose(UMP_MSG_TYPE_DATA, group, status, cvt->len);
261 	offset = 8;
262 	for (i = 0; i < cvt->len; i++) {
263 		*data |= cvt->buf[i] << offset;
264 		if (!offset) {
265 			offset = 24;
266 			data++;
267 		} else
268 			offset -= 8;
269 	}
270 	cvt->len = 0;
271 	if (finish)
272 		cvt->in_sysex = 0;
273 	else
274 		cvt->in_sysex++;
275 	return 8;
276 }
277 
278 /* convert to a UMP System message */
279 static int cvt_legacy_system_to_ump(struct ump_cvt_to_ump *cvt,
280 				    unsigned char group, u32 *data)
281 {
282 	data[0] = ump_compose(UMP_MSG_TYPE_SYSTEM, group, 0, cvt->buf[0]);
283 	if (cvt->cmd_bytes > 1)
284 		data[0] |= cvt->buf[1] << 8;
285 	if (cvt->cmd_bytes > 2)
286 		data[0] |= cvt->buf[2];
287 	return 4;
288 }
289 
290 static void fill_rpn(struct ump_cvt_to_ump_bank *cc,
291 		     union snd_ump_midi2_msg *midi2)
292 {
293 	if (cc->rpn_set) {
294 		midi2->rpn.status = UMP_MSG_STATUS_RPN;
295 		midi2->rpn.bank = cc->cc_rpn_msb;
296 		midi2->rpn.index = cc->cc_rpn_lsb;
297 		cc->rpn_set = 0;
298 		cc->cc_rpn_msb = cc->cc_rpn_lsb = 0;
299 	} else {
300 		midi2->rpn.status = UMP_MSG_STATUS_NRPN;
301 		midi2->rpn.bank = cc->cc_nrpn_msb;
302 		midi2->rpn.index = cc->cc_nrpn_lsb;
303 		cc->nrpn_set = 0;
304 		cc->cc_nrpn_msb = cc->cc_nrpn_lsb = 0;
305 	}
306 	midi2->rpn.data = upscale_14_to_32bit((cc->cc_data_msb << 7) |
307 					      cc->cc_data_lsb);
308 	cc->cc_data_msb = cc->cc_data_lsb = 0;
309 }
310 
311 /* convert to a MIDI 1.0 Channel Voice message */
312 static int cvt_legacy_cmd_to_ump(struct ump_cvt_to_ump *cvt,
313 				 unsigned char group,
314 				 unsigned int protocol,
315 				 u32 *data, unsigned char bytes)
316 {
317 	const unsigned char *buf = cvt->buf;
318 	struct ump_cvt_to_ump_bank *cc;
319 	union snd_ump_midi2_msg *midi2 = (union snd_ump_midi2_msg *)data;
320 	unsigned char status, channel;
321 
322 	BUILD_BUG_ON(sizeof(union snd_ump_midi1_msg) != 4);
323 	BUILD_BUG_ON(sizeof(union snd_ump_midi2_msg) != 8);
324 
325 	/* for MIDI 1.0 UMP, it's easy, just pack it into UMP */
326 	if (protocol & SNDRV_UMP_EP_INFO_PROTO_MIDI1) {
327 		data[0] = ump_compose(UMP_MSG_TYPE_MIDI1_CHANNEL_VOICE,
328 				      group, 0, buf[0]);
329 		data[0] |= buf[1] << 8;
330 		if (bytes > 2)
331 			data[0] |= buf[2];
332 		return 4;
333 	}
334 
335 	status = *buf >> 4;
336 	channel = *buf & 0x0f;
337 	cc = &cvt->bank[channel];
338 
339 	/* special handling: treat note-on with 0 velocity as note-off */
340 	if (status == UMP_MSG_STATUS_NOTE_ON && !buf[2])
341 		status = UMP_MSG_STATUS_NOTE_OFF;
342 
343 	/* initialize the packet */
344 	data[0] = ump_compose(UMP_MSG_TYPE_MIDI2_CHANNEL_VOICE,
345 			      group, status, channel);
346 	data[1] = 0;
347 
348 	switch (status) {
349 	case UMP_MSG_STATUS_NOTE_ON:
350 	case UMP_MSG_STATUS_NOTE_OFF:
351 		midi2->note.note = buf[1];
352 		midi2->note.velocity = upscale_7_to_16bit(buf[2]);
353 		break;
354 	case UMP_MSG_STATUS_POLY_PRESSURE:
355 		midi2->paf.note = buf[1];
356 		midi2->paf.data = upscale_7_to_32bit(buf[2]);
357 		break;
358 	case UMP_MSG_STATUS_CC:
359 		switch (buf[1]) {
360 		case UMP_CC_RPN_MSB:
361 			cc->rpn_set = 1;
362 			cc->cc_rpn_msb = buf[2];
363 			return 0; // skip
364 		case UMP_CC_RPN_LSB:
365 			cc->rpn_set = 1;
366 			cc->cc_rpn_lsb = buf[2];
367 			return 0; // skip
368 		case UMP_CC_NRPN_MSB:
369 			cc->nrpn_set = 1;
370 			cc->cc_nrpn_msb = buf[2];
371 			return 0; // skip
372 		case UMP_CC_NRPN_LSB:
373 			cc->nrpn_set = 1;
374 			cc->cc_nrpn_lsb = buf[2];
375 			return 0; // skip
376 		case UMP_CC_DATA:
377 			cc->cc_data_msb = buf[2];
378 			return 0; // skip
379 		case UMP_CC_BANK_SELECT:
380 			cc->bank_set = 1;
381 			cc->cc_bank_msb = buf[2];
382 			return 0; // skip
383 		case UMP_CC_BANK_SELECT_LSB:
384 			cc->bank_set = 1;
385 			cc->cc_bank_lsb = buf[2];
386 			return 0; // skip
387 		case UMP_CC_DATA_LSB:
388 			cc->cc_data_lsb = buf[2];
389 			if (cc->rpn_set || cc->nrpn_set)
390 				fill_rpn(cc, midi2);
391 			else
392 				return 0; // skip
393 			break;
394 		default:
395 			midi2->cc.index = buf[1];
396 			midi2->cc.data = upscale_7_to_32bit(buf[2]);
397 			break;
398 		}
399 		break;
400 	case UMP_MSG_STATUS_PROGRAM:
401 		midi2->pg.program = buf[1];
402 		if (cc->bank_set) {
403 			midi2->pg.bank_valid = 1;
404 			midi2->pg.bank_msb = cc->cc_bank_msb;
405 			midi2->pg.bank_lsb = cc->cc_bank_lsb;
406 			cc->bank_set = 0;
407 		}
408 		break;
409 	case UMP_MSG_STATUS_CHANNEL_PRESSURE:
410 		midi2->caf.data = upscale_7_to_32bit(buf[1]);
411 		break;
412 	case UMP_MSG_STATUS_PITCH_BEND:
413 		midi2->pb.data = upscale_14_to_32bit(buf[1] | (buf[2] << 7));
414 		break;
415 	default:
416 		return 0;
417 	}
418 
419 	return 8;
420 }
421 
422 static int do_convert_to_ump(struct ump_cvt_to_ump *cvt, unsigned char group,
423 			     unsigned int protocol, unsigned char c, u32 *data)
424 {
425 	/* bytes for 0x80-0xf0 */
426 	static unsigned char cmd_bytes[8] = {
427 		3, 3, 3, 3, 2, 2, 3, 0
428 	};
429 	/* bytes for 0xf0-0xff */
430 	static unsigned char system_bytes[16] = {
431 		0, 2, 3, 2, 0, 0, 1, 0, 1, 1, 1, 1, 0, 0, 1, 1
432 	};
433 	unsigned char bytes;
434 
435 	if (c == UMP_MIDI1_MSG_SYSEX_START) {
436 		cvt->in_sysex = 1;
437 		cvt->len = 0;
438 		return 0;
439 	}
440 	if (c == UMP_MIDI1_MSG_SYSEX_END) {
441 		if (!cvt->in_sysex)
442 			return 0; /* skip */
443 		return cvt_legacy_sysex_to_ump(cvt, group, data, true);
444 	}
445 
446 	if ((c & 0xf0) == UMP_MIDI1_MSG_REALTIME) {
447 		bytes = system_bytes[c & 0x0f];
448 		if (!bytes)
449 			return 0; /* skip */
450 		if (bytes == 1) {
451 			data[0] = ump_compose(UMP_MSG_TYPE_SYSTEM, group, 0, c);
452 			return 4;
453 		}
454 		cvt->buf[0] = c;
455 		cvt->len = 1;
456 		cvt->cmd_bytes = bytes;
457 		cvt->in_sysex = 0; /* abort SysEx */
458 		return 0;
459 	}
460 
461 	if (c & 0x80) {
462 		bytes = cmd_bytes[(c >> 4) & 7];
463 		cvt->buf[0] = c;
464 		cvt->len = 1;
465 		cvt->cmd_bytes = bytes;
466 		cvt->in_sysex = 0; /* abort SysEx */
467 		return 0;
468 	}
469 
470 	if (cvt->in_sysex) {
471 		cvt->buf[cvt->len++] = c;
472 		if (cvt->len == 6)
473 			return cvt_legacy_sysex_to_ump(cvt, group, data, false);
474 		return 0;
475 	}
476 
477 	if (!cvt->len)
478 		return 0;
479 
480 	cvt->buf[cvt->len++] = c;
481 	if (cvt->len < cvt->cmd_bytes)
482 		return 0;
483 	cvt->len = 1;
484 	if ((cvt->buf[0] & 0xf0) == UMP_MIDI1_MSG_REALTIME)
485 		return cvt_legacy_system_to_ump(cvt, group, data);
486 	return cvt_legacy_cmd_to_ump(cvt, group, protocol, data, cvt->cmd_bytes);
487 }
488 
489 /**
490  * snd_ump_convert_to_ump - convert legacy MIDI byte to UMP packet
491  * @cvt: converter context
492  * @group: target UMP group
493  * @protocol: target UMP protocol
494  * @c: MIDI 1.0 byte data
495  *
496  * Feed a MIDI 1.0 byte @c and convert to a UMP packet if completed.
497  * The result is stored in the buffer in @cvt.
498  */
499 void snd_ump_convert_to_ump(struct ump_cvt_to_ump *cvt, unsigned char group,
500 			    unsigned int protocol, unsigned char c)
501 {
502 	cvt->ump_bytes = do_convert_to_ump(cvt, group, protocol, c, cvt->ump);
503 }
504 EXPORT_SYMBOL_GPL(snd_ump_convert_to_ump);
505