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 37MODULE_AUTHOR("Takashi Iwai <tiwai@suse.de>"); 38MODULE_DESCRIPTION("Virtual Raw MIDI client on Sequencer"); 39MODULE_LICENSE("GPL"); 40 41/* 42 * initialize an event record 43 */ 44static 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() */ 67static int dump_to_rawmidi(void *ptr, void *buf, int count) 68{ 69 return snd_rawmidi_receive(ptr, buf, count); 70} 71 72static 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(&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(ev, dump_to_rawmidi, vmidi->substream); 91 snd_midi_event_reset_decode(vmidi->parser); 92 } else { 93 len = snd_midi_event_decode(vmidi->parser, msg, sizeof(msg), ev); 94 if (len > 0) 95 snd_rawmidi_receive(vmidi->substream, msg, len); 96 } 97 } 98 if (atomic) 99 read_unlock(&rdev->filelist_lock); 100 else 101 up_read(&rdev->filelist_sem); 102 103 return 0; 104} 105 106/* 107 * event handler of virmidi port 108 */ 109static 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 */ 123static 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 */ 133static 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, &input, 1) != 1) 152 break; 153 if (!snd_midi_event_encode_byte(vmidi->parser, input, 154 &vmidi->event)) 155 continue; 156 if (vmidi->event.type != SNDRV_SEQ_EVENT_NONE) { 157 ret = snd_seq_kernel_client_dispatch(vmidi->client, 158 &vmidi->event, 159 false, 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 */ 172static 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(system_highpri_wq, &vmidi->output_work); 179} 180 181/* 182 * open rawmidi handle for input 183 */ 184static 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(sizeof(*vmidi), GFP_KERNEL); 191 if (vmidi == NULL) 192 return -ENOMEM; 193 vmidi->substream = substream; 194 if (snd_midi_event_new(0, &vmidi->parser) < 0) { 195 kfree(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)(&rdev->filelist_lock); 204 list_add_tail(&vmidi->list, &rdev->filelist); 205 } 206 vmidi->rdev = rdev; 207 return 0; 208} 209 210/* 211 * open rawmidi handle for output 212 */ 213static 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(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, &vmidi->parser) < 0) { 224 kfree(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, &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 */ 240static 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)(&rdev->filelist_lock); 247 list_del(&vmidi->list); 248 } 249 snd_midi_event_free(vmidi->parser); 250 substream->runtime->private_data = NULL; 251 kfree(vmidi); 252 return 0; 253} 254 255/* 256 * close rawmidi handle for output 257 */ 258static 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(&vmidi->output_work); 264 snd_midi_event_free(vmidi->parser); 265 substream->runtime->private_data = NULL; 266 kfree(vmidi); 267 return 0; 268} 269 270/* 271 * drain output work queue 272 */ 273static void snd_virmidi_output_drain(struct snd_rawmidi_substream *substream) 274{ 275 struct snd_virmidi *vmidi = substream->runtime->private_data; 276 277 flush_work(&vmidi->output_work); 278} 279 280/* 281 * subscribe callback - allow output to rawmidi device 282 */ 283static 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(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 */ 298static 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(rdev->card->module); 306 return 0; 307} 308 309 310/* 311 * use callback - allow input to rawmidi device 312 */ 313static 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(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 */ 328static 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(rdev->card->module); 336 return 0; 337} 338 339 340/* 341 * Register functions 342 */ 343 344static 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 350static 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 */ 360static 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(sizeof(*pinfo), GFP_KERNEL); 371 if (!pinfo) 372 return -ENOMEM; 373 374 client = snd_seq_create_kernel_client(rdev->card, rdev->device, 375 "%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(pinfo->name, "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, 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 */ 418static void snd_virmidi_dev_detach_seq(struct snd_virmidi_dev *rdev) 419{ 420 if (rdev->client >= 0) { 421 snd_seq_delete_kernel_client(rdev->client); 422 rdev->client = -1; 423 } 424} 425 426/* 427 * register the device 428 */ 429static 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 */ 456static 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 */ 468static 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 */ 476static void snd_virmidi_free(struct snd_rawmidi *rmidi) 477{ 478 struct snd_virmidi_dev *rdev = rmidi->private_data; 479 kfree(rdev); 480} 481 482/* 483 * create a new device 484 * 485 */ 486/* exported */ 487int 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, "VirMidi", device, 495 16, /* may be configurable */ 496 16, /* may be configurable */ 497 &rmidi); 498 if (err < 0) 499 return err; 500 strcpy(rmidi->name, rmidi->id); 501 rdev = kzalloc(sizeof(*rdev), GFP_KERNEL); 502 if (rdev == NULL) { 503 snd_device_free(card, 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(&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, SNDRV_RAWMIDI_STREAM_INPUT, &snd_virmidi_input_ops); 518 snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_OUTPUT, &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} 525EXPORT_SYMBOL(snd_virmidi_new); 526