1 | // SPDX-License-Identifier: GPL-2.0-or-later |
2 | /* |
3 | * Virtual Raw MIDI client on Sequencer |
4 | * |
5 | * Copyright (c) 2000 by Takashi Iwai <tiwai@suse.de>, |
6 | * Jaroslav Kysela <perex@perex.cz> |
7 | */ |
8 | |
9 | /* |
10 | * Virtual Raw MIDI client |
11 | * |
12 | * The virtual rawmidi client is a sequencer client which associate |
13 | * a rawmidi device file. The created rawmidi device file can be |
14 | * accessed as a normal raw midi, but its MIDI source and destination |
15 | * are arbitrary. For example, a user-client software synth connected |
16 | * to this port can be used as a normal midi device as well. |
17 | * |
18 | * The virtual rawmidi device accepts also multiple opens. Each file |
19 | * has its own input buffer, so that no conflict would occur. The drain |
20 | * of input/output buffer acts only to the local buffer. |
21 | * |
22 | */ |
23 | |
24 | #include <linux/init.h> |
25 | #include <linux/wait.h> |
26 | #include <linux/module.h> |
27 | #include <linux/slab.h> |
28 | #include <sound/core.h> |
29 | #include <sound/rawmidi.h> |
30 | #include <sound/info.h> |
31 | #include <sound/control.h> |
32 | #include <sound/minors.h> |
33 | #include <sound/seq_kernel.h> |
34 | #include <sound/seq_midi_event.h> |
35 | #include <sound/seq_virmidi.h> |
36 | |
37 | MODULE_AUTHOR("Takashi Iwai <tiwai@suse.de>" ); |
38 | MODULE_DESCRIPTION("Virtual Raw MIDI client on Sequencer" ); |
39 | MODULE_LICENSE("GPL" ); |
40 | |
41 | /* |
42 | * initialize an event record |
43 | */ |
44 | static void snd_virmidi_init_event(struct snd_virmidi *vmidi, |
45 | struct snd_seq_event *ev) |
46 | { |
47 | memset(ev, 0, sizeof(*ev)); |
48 | ev->source.port = vmidi->port; |
49 | switch (vmidi->seq_mode) { |
50 | case SNDRV_VIRMIDI_SEQ_DISPATCH: |
51 | ev->dest.client = SNDRV_SEQ_ADDRESS_SUBSCRIBERS; |
52 | break; |
53 | case SNDRV_VIRMIDI_SEQ_ATTACH: |
54 | /* FIXME: source and destination are same - not good.. */ |
55 | ev->dest.client = vmidi->client; |
56 | ev->dest.port = vmidi->port; |
57 | break; |
58 | } |
59 | ev->type = SNDRV_SEQ_EVENT_NONE; |
60 | } |
61 | |
62 | /* |
63 | * decode input event and put to read buffer of each opened file |
64 | */ |
65 | |
66 | /* callback for snd_seq_dump_var_event(), bridging to snd_rawmidi_receive() */ |
67 | static int dump_to_rawmidi(void *ptr, void *buf, int count) |
68 | { |
69 | return snd_rawmidi_receive(substream: ptr, buffer: buf, count); |
70 | } |
71 | |
72 | static int snd_virmidi_dev_receive_event(struct snd_virmidi_dev *rdev, |
73 | struct snd_seq_event *ev, |
74 | bool atomic) |
75 | { |
76 | struct snd_virmidi *vmidi; |
77 | unsigned char msg[4]; |
78 | int len; |
79 | |
80 | if (atomic) |
81 | read_lock(&rdev->filelist_lock); |
82 | else |
83 | down_read(sem: &rdev->filelist_sem); |
84 | list_for_each_entry(vmidi, &rdev->filelist, list) { |
85 | if (!READ_ONCE(vmidi->trigger)) |
86 | continue; |
87 | if (ev->type == SNDRV_SEQ_EVENT_SYSEX) { |
88 | if ((ev->flags & SNDRV_SEQ_EVENT_LENGTH_MASK) != SNDRV_SEQ_EVENT_LENGTH_VARIABLE) |
89 | continue; |
90 | snd_seq_dump_var_event(event: ev, func: dump_to_rawmidi, private_data: vmidi->substream); |
91 | snd_midi_event_reset_decode(dev: vmidi->parser); |
92 | } else { |
93 | len = snd_midi_event_decode(dev: vmidi->parser, buf: msg, count: sizeof(msg), ev); |
94 | if (len > 0) |
95 | snd_rawmidi_receive(substream: vmidi->substream, buffer: msg, count: len); |
96 | } |
97 | } |
98 | if (atomic) |
99 | read_unlock(&rdev->filelist_lock); |
100 | else |
101 | up_read(sem: &rdev->filelist_sem); |
102 | |
103 | return 0; |
104 | } |
105 | |
106 | /* |
107 | * event handler of virmidi port |
108 | */ |
109 | static int snd_virmidi_event_input(struct snd_seq_event *ev, int direct, |
110 | void *private_data, int atomic, int hop) |
111 | { |
112 | struct snd_virmidi_dev *rdev; |
113 | |
114 | rdev = private_data; |
115 | if (!(rdev->flags & SNDRV_VIRMIDI_USE)) |
116 | return 0; /* ignored */ |
117 | return snd_virmidi_dev_receive_event(rdev, ev, atomic); |
118 | } |
119 | |
120 | /* |
121 | * trigger rawmidi stream for input |
122 | */ |
123 | static void snd_virmidi_input_trigger(struct snd_rawmidi_substream *substream, int up) |
124 | { |
125 | struct snd_virmidi *vmidi = substream->runtime->private_data; |
126 | |
127 | WRITE_ONCE(vmidi->trigger, !!up); |
128 | } |
129 | |
130 | /* process rawmidi bytes and send events; |
131 | * we need no lock here for vmidi->event since it's handled only in this work |
132 | */ |
133 | static void snd_vmidi_output_work(struct work_struct *work) |
134 | { |
135 | struct snd_virmidi *vmidi; |
136 | struct snd_rawmidi_substream *substream; |
137 | unsigned char input; |
138 | int ret; |
139 | |
140 | vmidi = container_of(work, struct snd_virmidi, output_work); |
141 | substream = vmidi->substream; |
142 | |
143 | /* discard the outputs in dispatch mode unless subscribed */ |
144 | if (vmidi->seq_mode == SNDRV_VIRMIDI_SEQ_DISPATCH && |
145 | !(vmidi->rdev->flags & SNDRV_VIRMIDI_SUBSCRIBE)) { |
146 | snd_rawmidi_proceed(substream); |
147 | return; |
148 | } |
149 | |
150 | while (READ_ONCE(vmidi->trigger)) { |
151 | if (snd_rawmidi_transmit(substream, buffer: &input, count: 1) != 1) |
152 | break; |
153 | if (!snd_midi_event_encode_byte(dev: vmidi->parser, c: input, |
154 | ev: &vmidi->event)) |
155 | continue; |
156 | if (vmidi->event.type != SNDRV_SEQ_EVENT_NONE) { |
157 | ret = snd_seq_kernel_client_dispatch(client: vmidi->client, |
158 | ev: &vmidi->event, |
159 | atomic: false, hop: 0); |
160 | vmidi->event.type = SNDRV_SEQ_EVENT_NONE; |
161 | if (ret < 0) |
162 | break; |
163 | } |
164 | /* rawmidi input might be huge, allow to have a break */ |
165 | cond_resched(); |
166 | } |
167 | } |
168 | |
169 | /* |
170 | * trigger rawmidi stream for output |
171 | */ |
172 | static void snd_virmidi_output_trigger(struct snd_rawmidi_substream *substream, int up) |
173 | { |
174 | struct snd_virmidi *vmidi = substream->runtime->private_data; |
175 | |
176 | WRITE_ONCE(vmidi->trigger, !!up); |
177 | if (up) |
178 | queue_work(wq: system_highpri_wq, work: &vmidi->output_work); |
179 | } |
180 | |
181 | /* |
182 | * open rawmidi handle for input |
183 | */ |
184 | static int snd_virmidi_input_open(struct snd_rawmidi_substream *substream) |
185 | { |
186 | struct snd_virmidi_dev *rdev = substream->rmidi->private_data; |
187 | struct snd_rawmidi_runtime *runtime = substream->runtime; |
188 | struct snd_virmidi *vmidi; |
189 | |
190 | vmidi = kzalloc(size: sizeof(*vmidi), GFP_KERNEL); |
191 | if (vmidi == NULL) |
192 | return -ENOMEM; |
193 | vmidi->substream = substream; |
194 | if (snd_midi_event_new(bufsize: 0, rdev: &vmidi->parser) < 0) { |
195 | kfree(objp: vmidi); |
196 | return -ENOMEM; |
197 | } |
198 | vmidi->seq_mode = rdev->seq_mode; |
199 | vmidi->client = rdev->client; |
200 | vmidi->port = rdev->port; |
201 | runtime->private_data = vmidi; |
202 | scoped_guard(rwsem_write, &rdev->filelist_sem) { |
203 | guard(write_lock_irq)(l: &rdev->filelist_lock); |
204 | list_add_tail(new: &vmidi->list, head: &rdev->filelist); |
205 | } |
206 | vmidi->rdev = rdev; |
207 | return 0; |
208 | } |
209 | |
210 | /* |
211 | * open rawmidi handle for output |
212 | */ |
213 | static int snd_virmidi_output_open(struct snd_rawmidi_substream *substream) |
214 | { |
215 | struct snd_virmidi_dev *rdev = substream->rmidi->private_data; |
216 | struct snd_rawmidi_runtime *runtime = substream->runtime; |
217 | struct snd_virmidi *vmidi; |
218 | |
219 | vmidi = kzalloc(size: sizeof(*vmidi), GFP_KERNEL); |
220 | if (vmidi == NULL) |
221 | return -ENOMEM; |
222 | vmidi->substream = substream; |
223 | if (snd_midi_event_new(MAX_MIDI_EVENT_BUF, rdev: &vmidi->parser) < 0) { |
224 | kfree(objp: vmidi); |
225 | return -ENOMEM; |
226 | } |
227 | vmidi->seq_mode = rdev->seq_mode; |
228 | vmidi->client = rdev->client; |
229 | vmidi->port = rdev->port; |
230 | snd_virmidi_init_event(vmidi, ev: &vmidi->event); |
231 | vmidi->rdev = rdev; |
232 | INIT_WORK(&vmidi->output_work, snd_vmidi_output_work); |
233 | runtime->private_data = vmidi; |
234 | return 0; |
235 | } |
236 | |
237 | /* |
238 | * close rawmidi handle for input |
239 | */ |
240 | static int snd_virmidi_input_close(struct snd_rawmidi_substream *substream) |
241 | { |
242 | struct snd_virmidi_dev *rdev = substream->rmidi->private_data; |
243 | struct snd_virmidi *vmidi = substream->runtime->private_data; |
244 | |
245 | scoped_guard(rwsem_write, &rdev->filelist_sem) { |
246 | guard(write_lock_irq)(l: &rdev->filelist_lock); |
247 | list_del(entry: &vmidi->list); |
248 | } |
249 | snd_midi_event_free(dev: vmidi->parser); |
250 | substream->runtime->private_data = NULL; |
251 | kfree(objp: vmidi); |
252 | return 0; |
253 | } |
254 | |
255 | /* |
256 | * close rawmidi handle for output |
257 | */ |
258 | static int snd_virmidi_output_close(struct snd_rawmidi_substream *substream) |
259 | { |
260 | struct snd_virmidi *vmidi = substream->runtime->private_data; |
261 | |
262 | WRITE_ONCE(vmidi->trigger, false); /* to be sure */ |
263 | cancel_work_sync(work: &vmidi->output_work); |
264 | snd_midi_event_free(dev: vmidi->parser); |
265 | substream->runtime->private_data = NULL; |
266 | kfree(objp: vmidi); |
267 | return 0; |
268 | } |
269 | |
270 | /* |
271 | * drain output work queue |
272 | */ |
273 | static void snd_virmidi_output_drain(struct snd_rawmidi_substream *substream) |
274 | { |
275 | struct snd_virmidi *vmidi = substream->runtime->private_data; |
276 | |
277 | flush_work(work: &vmidi->output_work); |
278 | } |
279 | |
280 | /* |
281 | * subscribe callback - allow output to rawmidi device |
282 | */ |
283 | static int snd_virmidi_subscribe(void *private_data, |
284 | struct snd_seq_port_subscribe *info) |
285 | { |
286 | struct snd_virmidi_dev *rdev; |
287 | |
288 | rdev = private_data; |
289 | if (!try_module_get(module: rdev->card->module)) |
290 | return -EFAULT; |
291 | rdev->flags |= SNDRV_VIRMIDI_SUBSCRIBE; |
292 | return 0; |
293 | } |
294 | |
295 | /* |
296 | * unsubscribe callback - disallow output to rawmidi device |
297 | */ |
298 | static int snd_virmidi_unsubscribe(void *private_data, |
299 | struct snd_seq_port_subscribe *info) |
300 | { |
301 | struct snd_virmidi_dev *rdev; |
302 | |
303 | rdev = private_data; |
304 | rdev->flags &= ~SNDRV_VIRMIDI_SUBSCRIBE; |
305 | module_put(module: rdev->card->module); |
306 | return 0; |
307 | } |
308 | |
309 | |
310 | /* |
311 | * use callback - allow input to rawmidi device |
312 | */ |
313 | static int snd_virmidi_use(void *private_data, |
314 | struct snd_seq_port_subscribe *info) |
315 | { |
316 | struct snd_virmidi_dev *rdev; |
317 | |
318 | rdev = private_data; |
319 | if (!try_module_get(module: rdev->card->module)) |
320 | return -EFAULT; |
321 | rdev->flags |= SNDRV_VIRMIDI_USE; |
322 | return 0; |
323 | } |
324 | |
325 | /* |
326 | * unuse callback - disallow input to rawmidi device |
327 | */ |
328 | static int snd_virmidi_unuse(void *private_data, |
329 | struct snd_seq_port_subscribe *info) |
330 | { |
331 | struct snd_virmidi_dev *rdev; |
332 | |
333 | rdev = private_data; |
334 | rdev->flags &= ~SNDRV_VIRMIDI_USE; |
335 | module_put(module: rdev->card->module); |
336 | return 0; |
337 | } |
338 | |
339 | |
340 | /* |
341 | * Register functions |
342 | */ |
343 | |
344 | static const struct snd_rawmidi_ops snd_virmidi_input_ops = { |
345 | .open = snd_virmidi_input_open, |
346 | .close = snd_virmidi_input_close, |
347 | .trigger = snd_virmidi_input_trigger, |
348 | }; |
349 | |
350 | static const struct snd_rawmidi_ops snd_virmidi_output_ops = { |
351 | .open = snd_virmidi_output_open, |
352 | .close = snd_virmidi_output_close, |
353 | .trigger = snd_virmidi_output_trigger, |
354 | .drain = snd_virmidi_output_drain, |
355 | }; |
356 | |
357 | /* |
358 | * create a sequencer client and a port |
359 | */ |
360 | static int snd_virmidi_dev_attach_seq(struct snd_virmidi_dev *rdev) |
361 | { |
362 | int client; |
363 | struct snd_seq_port_callback pcallbacks; |
364 | struct snd_seq_port_info *pinfo __free(kfree) = NULL; |
365 | int err; |
366 | |
367 | if (rdev->client >= 0) |
368 | return 0; |
369 | |
370 | pinfo = kzalloc(size: sizeof(*pinfo), GFP_KERNEL); |
371 | if (!pinfo) |
372 | return -ENOMEM; |
373 | |
374 | client = snd_seq_create_kernel_client(card: rdev->card, client_index: rdev->device, |
375 | name_fmt: "%s %d-%d" , rdev->rmidi->name, |
376 | rdev->card->number, |
377 | rdev->device); |
378 | if (client < 0) |
379 | return client; |
380 | rdev->client = client; |
381 | |
382 | /* create a port */ |
383 | pinfo->addr.client = client; |
384 | sprintf(buf: pinfo->name, fmt: "VirMIDI %d-%d" , rdev->card->number, rdev->device); |
385 | /* set all capabilities */ |
386 | pinfo->capability |= SNDRV_SEQ_PORT_CAP_WRITE | SNDRV_SEQ_PORT_CAP_SYNC_WRITE | SNDRV_SEQ_PORT_CAP_SUBS_WRITE; |
387 | pinfo->capability |= SNDRV_SEQ_PORT_CAP_READ | SNDRV_SEQ_PORT_CAP_SYNC_READ | SNDRV_SEQ_PORT_CAP_SUBS_READ; |
388 | pinfo->capability |= SNDRV_SEQ_PORT_CAP_DUPLEX; |
389 | pinfo->direction = SNDRV_SEQ_PORT_DIR_BIDIRECTION; |
390 | pinfo->type = SNDRV_SEQ_PORT_TYPE_MIDI_GENERIC |
391 | | SNDRV_SEQ_PORT_TYPE_SOFTWARE |
392 | | SNDRV_SEQ_PORT_TYPE_PORT; |
393 | pinfo->midi_channels = 16; |
394 | memset(&pcallbacks, 0, sizeof(pcallbacks)); |
395 | pcallbacks.owner = THIS_MODULE; |
396 | pcallbacks.private_data = rdev; |
397 | pcallbacks.subscribe = snd_virmidi_subscribe; |
398 | pcallbacks.unsubscribe = snd_virmidi_unsubscribe; |
399 | pcallbacks.use = snd_virmidi_use; |
400 | pcallbacks.unuse = snd_virmidi_unuse; |
401 | pcallbacks.event_input = snd_virmidi_event_input; |
402 | pinfo->kernel = &pcallbacks; |
403 | err = snd_seq_kernel_client_ctl(client, SNDRV_SEQ_IOCTL_CREATE_PORT, arg: pinfo); |
404 | if (err < 0) { |
405 | snd_seq_delete_kernel_client(client); |
406 | rdev->client = -1; |
407 | return err; |
408 | } |
409 | |
410 | rdev->port = pinfo->addr.port; |
411 | return 0; /* success */ |
412 | } |
413 | |
414 | |
415 | /* |
416 | * release the sequencer client |
417 | */ |
418 | static void snd_virmidi_dev_detach_seq(struct snd_virmidi_dev *rdev) |
419 | { |
420 | if (rdev->client >= 0) { |
421 | snd_seq_delete_kernel_client(client: rdev->client); |
422 | rdev->client = -1; |
423 | } |
424 | } |
425 | |
426 | /* |
427 | * register the device |
428 | */ |
429 | static int snd_virmidi_dev_register(struct snd_rawmidi *rmidi) |
430 | { |
431 | struct snd_virmidi_dev *rdev = rmidi->private_data; |
432 | int err; |
433 | |
434 | switch (rdev->seq_mode) { |
435 | case SNDRV_VIRMIDI_SEQ_DISPATCH: |
436 | err = snd_virmidi_dev_attach_seq(rdev); |
437 | if (err < 0) |
438 | return err; |
439 | break; |
440 | case SNDRV_VIRMIDI_SEQ_ATTACH: |
441 | if (rdev->client == 0) |
442 | return -EINVAL; |
443 | /* should check presence of port more strictly.. */ |
444 | break; |
445 | default: |
446 | pr_err("ALSA: seq_virmidi: seq_mode is not set: %d\n" , rdev->seq_mode); |
447 | return -EINVAL; |
448 | } |
449 | return 0; |
450 | } |
451 | |
452 | |
453 | /* |
454 | * unregister the device |
455 | */ |
456 | static int snd_virmidi_dev_unregister(struct snd_rawmidi *rmidi) |
457 | { |
458 | struct snd_virmidi_dev *rdev = rmidi->private_data; |
459 | |
460 | if (rdev->seq_mode == SNDRV_VIRMIDI_SEQ_DISPATCH) |
461 | snd_virmidi_dev_detach_seq(rdev); |
462 | return 0; |
463 | } |
464 | |
465 | /* |
466 | * |
467 | */ |
468 | static const struct snd_rawmidi_global_ops snd_virmidi_global_ops = { |
469 | .dev_register = snd_virmidi_dev_register, |
470 | .dev_unregister = snd_virmidi_dev_unregister, |
471 | }; |
472 | |
473 | /* |
474 | * free device |
475 | */ |
476 | static void snd_virmidi_free(struct snd_rawmidi *rmidi) |
477 | { |
478 | struct snd_virmidi_dev *rdev = rmidi->private_data; |
479 | kfree(objp: rdev); |
480 | } |
481 | |
482 | /* |
483 | * create a new device |
484 | * |
485 | */ |
486 | /* exported */ |
487 | int snd_virmidi_new(struct snd_card *card, int device, struct snd_rawmidi **rrmidi) |
488 | { |
489 | struct snd_rawmidi *rmidi; |
490 | struct snd_virmidi_dev *rdev; |
491 | int err; |
492 | |
493 | *rrmidi = NULL; |
494 | err = snd_rawmidi_new(card, id: "VirMidi" , device, |
495 | output_count: 16, /* may be configurable */ |
496 | input_count: 16, /* may be configurable */ |
497 | rmidi: &rmidi); |
498 | if (err < 0) |
499 | return err; |
500 | strcpy(p: rmidi->name, q: rmidi->id); |
501 | rdev = kzalloc(size: sizeof(*rdev), GFP_KERNEL); |
502 | if (rdev == NULL) { |
503 | snd_device_free(card, device_data: rmidi); |
504 | return -ENOMEM; |
505 | } |
506 | rdev->card = card; |
507 | rdev->rmidi = rmidi; |
508 | rdev->device = device; |
509 | rdev->client = -1; |
510 | init_rwsem(&rdev->filelist_sem); |
511 | rwlock_init(&rdev->filelist_lock); |
512 | INIT_LIST_HEAD(list: &rdev->filelist); |
513 | rdev->seq_mode = SNDRV_VIRMIDI_SEQ_DISPATCH; |
514 | rmidi->private_data = rdev; |
515 | rmidi->private_free = snd_virmidi_free; |
516 | rmidi->ops = &snd_virmidi_global_ops; |
517 | snd_rawmidi_set_ops(rmidi, stream: SNDRV_RAWMIDI_STREAM_INPUT, ops: &snd_virmidi_input_ops); |
518 | snd_rawmidi_set_ops(rmidi, stream: SNDRV_RAWMIDI_STREAM_OUTPUT, ops: &snd_virmidi_output_ops); |
519 | rmidi->info_flags = SNDRV_RAWMIDI_INFO_INPUT | |
520 | SNDRV_RAWMIDI_INFO_OUTPUT | |
521 | SNDRV_RAWMIDI_INFO_DUPLEX; |
522 | *rrmidi = rmidi; |
523 | return 0; |
524 | } |
525 | EXPORT_SYMBOL(snd_virmidi_new); |
526 | |