1 /* 2 * Virtual Raw MIDI client on Sequencer 3 * 4 * Copyright (c) 2000 by Takashi Iwai <tiwai@suse.de>, 5 * Jaroslav Kysela <perex@perex.cz> 6 * 7 * This program is free software; you can redistribute it and/or modify 8 * it under the terms of the GNU General Public License as published by 9 * the Free Software Foundation; either version 2 of the License, or 10 * (at your option) any later version. 11 * 12 * This program is distributed in the hope that it will be useful, 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 * GNU General Public License for more details. 16 * 17 * You should have received a copy of the GNU General Public License 18 * along with this program; if not, write to the Free Software 19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 20 * 21 */ 22 23 /* 24 * Virtual Raw MIDI client 25 * 26 * The virtual rawmidi client is a sequencer client which associate 27 * a rawmidi device file. The created rawmidi device file can be 28 * accessed as a normal raw midi, but its MIDI source and destination 29 * are arbitrary. For example, a user-client software synth connected 30 * to this port can be used as a normal midi device as well. 31 * 32 * The virtual rawmidi device accepts also multiple opens. Each file 33 * has its own input buffer, so that no conflict would occur. The drain 34 * of input/output buffer acts only to the local buffer. 35 * 36 */ 37 38 #include <linux/init.h> 39 #include <linux/wait.h> 40 #include <linux/module.h> 41 #include <linux/slab.h> 42 #include <sound/core.h> 43 #include <sound/rawmidi.h> 44 #include <sound/info.h> 45 #include <sound/control.h> 46 #include <sound/minors.h> 47 #include <sound/seq_kernel.h> 48 #include <sound/seq_midi_event.h> 49 #include <sound/seq_virmidi.h> 50 51 MODULE_AUTHOR("Takashi Iwai <tiwai@suse.de>"); 52 MODULE_DESCRIPTION("Virtual Raw MIDI client on Sequencer"); 53 MODULE_LICENSE("GPL"); 54 55 /* 56 * initialize an event record 57 */ 58 static void snd_virmidi_init_event(struct snd_virmidi *vmidi, 59 struct snd_seq_event *ev) 60 { 61 memset(ev, 0, sizeof(*ev)); 62 ev->source.port = vmidi->port; 63 switch (vmidi->seq_mode) { 64 case SNDRV_VIRMIDI_SEQ_DISPATCH: 65 ev->dest.client = SNDRV_SEQ_ADDRESS_SUBSCRIBERS; 66 break; 67 case SNDRV_VIRMIDI_SEQ_ATTACH: 68 /* FIXME: source and destination are same - not good.. */ 69 ev->dest.client = vmidi->client; 70 ev->dest.port = vmidi->port; 71 break; 72 } 73 ev->type = SNDRV_SEQ_EVENT_NONE; 74 } 75 76 /* 77 * decode input event and put to read buffer of each opened file 78 */ 79 static int snd_virmidi_dev_receive_event(struct snd_virmidi_dev *rdev, 80 struct snd_seq_event *ev, 81 bool atomic) 82 { 83 struct snd_virmidi *vmidi; 84 unsigned char msg[4]; 85 int len; 86 87 if (atomic) 88 read_lock(&rdev->filelist_lock); 89 else 90 down_read(&rdev->filelist_sem); 91 list_for_each_entry(vmidi, &rdev->filelist, list) { 92 if (!READ_ONCE(vmidi->trigger)) 93 continue; 94 if (ev->type == SNDRV_SEQ_EVENT_SYSEX) { 95 if ((ev->flags & SNDRV_SEQ_EVENT_LENGTH_MASK) != SNDRV_SEQ_EVENT_LENGTH_VARIABLE) 96 continue; 97 snd_seq_dump_var_event(ev, (snd_seq_dump_func_t)snd_rawmidi_receive, vmidi->substream); 98 } else { 99 len = snd_midi_event_decode(vmidi->parser, msg, sizeof(msg), ev); 100 if (len > 0) 101 snd_rawmidi_receive(vmidi->substream, msg, len); 102 } 103 } 104 if (atomic) 105 read_unlock(&rdev->filelist_lock); 106 else 107 up_read(&rdev->filelist_sem); 108 109 return 0; 110 } 111 112 /* 113 * event handler of virmidi port 114 */ 115 static int snd_virmidi_event_input(struct snd_seq_event *ev, int direct, 116 void *private_data, int atomic, int hop) 117 { 118 struct snd_virmidi_dev *rdev; 119 120 rdev = private_data; 121 if (!(rdev->flags & SNDRV_VIRMIDI_USE)) 122 return 0; /* ignored */ 123 return snd_virmidi_dev_receive_event(rdev, ev, atomic); 124 } 125 126 /* 127 * trigger rawmidi stream for input 128 */ 129 static void snd_virmidi_input_trigger(struct snd_rawmidi_substream *substream, int up) 130 { 131 struct snd_virmidi *vmidi = substream->runtime->private_data; 132 133 WRITE_ONCE(vmidi->trigger, !!up); 134 } 135 136 /* process rawmidi bytes and send events; 137 * we need no lock here for vmidi->event since it's handled only in this work 138 */ 139 static void snd_vmidi_output_work(struct work_struct *work) 140 { 141 struct snd_virmidi *vmidi; 142 struct snd_rawmidi_substream *substream; 143 unsigned char input; 144 int ret; 145 146 vmidi = container_of(work, struct snd_virmidi, output_work); 147 substream = vmidi->substream; 148 149 /* discard the outputs in dispatch mode unless subscribed */ 150 if (vmidi->seq_mode == SNDRV_VIRMIDI_SEQ_DISPATCH && 151 !(vmidi->rdev->flags & SNDRV_VIRMIDI_SUBSCRIBE)) { 152 snd_rawmidi_proceed(substream); 153 return; 154 } 155 156 while (READ_ONCE(vmidi->trigger)) { 157 if (snd_rawmidi_transmit(substream, &input, 1) != 1) 158 break; 159 if (!snd_midi_event_encode_byte(vmidi->parser, input, 160 &vmidi->event)) 161 continue; 162 if (vmidi->event.type != SNDRV_SEQ_EVENT_NONE) { 163 ret = snd_seq_kernel_client_dispatch(vmidi->client, 164 &vmidi->event, 165 false, 0); 166 vmidi->event.type = SNDRV_SEQ_EVENT_NONE; 167 if (ret < 0) 168 break; 169 } 170 /* rawmidi input might be huge, allow to have a break */ 171 cond_resched(); 172 } 173 } 174 175 /* 176 * trigger rawmidi stream for output 177 */ 178 static void snd_virmidi_output_trigger(struct snd_rawmidi_substream *substream, int up) 179 { 180 struct snd_virmidi *vmidi = substream->runtime->private_data; 181 182 WRITE_ONCE(vmidi->trigger, !!up); 183 if (up) 184 queue_work(system_highpri_wq, &vmidi->output_work); 185 } 186 187 /* 188 * open rawmidi handle for input 189 */ 190 static int snd_virmidi_input_open(struct snd_rawmidi_substream *substream) 191 { 192 struct snd_virmidi_dev *rdev = substream->rmidi->private_data; 193 struct snd_rawmidi_runtime *runtime = substream->runtime; 194 struct snd_virmidi *vmidi; 195 196 vmidi = kzalloc(sizeof(*vmidi), GFP_KERNEL); 197 if (vmidi == NULL) 198 return -ENOMEM; 199 vmidi->substream = substream; 200 if (snd_midi_event_new(0, &vmidi->parser) < 0) { 201 kfree(vmidi); 202 return -ENOMEM; 203 } 204 vmidi->seq_mode = rdev->seq_mode; 205 vmidi->client = rdev->client; 206 vmidi->port = rdev->port; 207 runtime->private_data = vmidi; 208 down_write(&rdev->filelist_sem); 209 write_lock_irq(&rdev->filelist_lock); 210 list_add_tail(&vmidi->list, &rdev->filelist); 211 write_unlock_irq(&rdev->filelist_lock); 212 up_write(&rdev->filelist_sem); 213 vmidi->rdev = rdev; 214 return 0; 215 } 216 217 /* 218 * open rawmidi handle for output 219 */ 220 static int snd_virmidi_output_open(struct snd_rawmidi_substream *substream) 221 { 222 struct snd_virmidi_dev *rdev = substream->rmidi->private_data; 223 struct snd_rawmidi_runtime *runtime = substream->runtime; 224 struct snd_virmidi *vmidi; 225 226 vmidi = kzalloc(sizeof(*vmidi), GFP_KERNEL); 227 if (vmidi == NULL) 228 return -ENOMEM; 229 vmidi->substream = substream; 230 if (snd_midi_event_new(MAX_MIDI_EVENT_BUF, &vmidi->parser) < 0) { 231 kfree(vmidi); 232 return -ENOMEM; 233 } 234 vmidi->seq_mode = rdev->seq_mode; 235 vmidi->client = rdev->client; 236 vmidi->port = rdev->port; 237 snd_virmidi_init_event(vmidi, &vmidi->event); 238 vmidi->rdev = rdev; 239 INIT_WORK(&vmidi->output_work, snd_vmidi_output_work); 240 runtime->private_data = vmidi; 241 return 0; 242 } 243 244 /* 245 * close rawmidi handle for input 246 */ 247 static int snd_virmidi_input_close(struct snd_rawmidi_substream *substream) 248 { 249 struct snd_virmidi_dev *rdev = substream->rmidi->private_data; 250 struct snd_virmidi *vmidi = substream->runtime->private_data; 251 252 down_write(&rdev->filelist_sem); 253 write_lock_irq(&rdev->filelist_lock); 254 list_del(&vmidi->list); 255 write_unlock_irq(&rdev->filelist_lock); 256 up_write(&rdev->filelist_sem); 257 snd_midi_event_free(vmidi->parser); 258 substream->runtime->private_data = NULL; 259 kfree(vmidi); 260 return 0; 261 } 262 263 /* 264 * close rawmidi handle for output 265 */ 266 static int snd_virmidi_output_close(struct snd_rawmidi_substream *substream) 267 { 268 struct snd_virmidi *vmidi = substream->runtime->private_data; 269 270 WRITE_ONCE(vmidi->trigger, false); /* to be sure */ 271 cancel_work_sync(&vmidi->output_work); 272 snd_midi_event_free(vmidi->parser); 273 substream->runtime->private_data = NULL; 274 kfree(vmidi); 275 return 0; 276 } 277 278 /* 279 * subscribe callback - allow output to rawmidi device 280 */ 281 static int snd_virmidi_subscribe(void *private_data, 282 struct snd_seq_port_subscribe *info) 283 { 284 struct snd_virmidi_dev *rdev; 285 286 rdev = private_data; 287 if (!try_module_get(rdev->card->module)) 288 return -EFAULT; 289 rdev->flags |= SNDRV_VIRMIDI_SUBSCRIBE; 290 return 0; 291 } 292 293 /* 294 * unsubscribe callback - disallow output to rawmidi device 295 */ 296 static int snd_virmidi_unsubscribe(void *private_data, 297 struct snd_seq_port_subscribe *info) 298 { 299 struct snd_virmidi_dev *rdev; 300 301 rdev = private_data; 302 rdev->flags &= ~SNDRV_VIRMIDI_SUBSCRIBE; 303 module_put(rdev->card->module); 304 return 0; 305 } 306 307 308 /* 309 * use callback - allow input to rawmidi device 310 */ 311 static int snd_virmidi_use(void *private_data, 312 struct snd_seq_port_subscribe *info) 313 { 314 struct snd_virmidi_dev *rdev; 315 316 rdev = private_data; 317 if (!try_module_get(rdev->card->module)) 318 return -EFAULT; 319 rdev->flags |= SNDRV_VIRMIDI_USE; 320 return 0; 321 } 322 323 /* 324 * unuse callback - disallow input to rawmidi device 325 */ 326 static int snd_virmidi_unuse(void *private_data, 327 struct snd_seq_port_subscribe *info) 328 { 329 struct snd_virmidi_dev *rdev; 330 331 rdev = private_data; 332 rdev->flags &= ~SNDRV_VIRMIDI_USE; 333 module_put(rdev->card->module); 334 return 0; 335 } 336 337 338 /* 339 * Register functions 340 */ 341 342 static const struct snd_rawmidi_ops snd_virmidi_input_ops = { 343 .open = snd_virmidi_input_open, 344 .close = snd_virmidi_input_close, 345 .trigger = snd_virmidi_input_trigger, 346 }; 347 348 static const struct snd_rawmidi_ops snd_virmidi_output_ops = { 349 .open = snd_virmidi_output_open, 350 .close = snd_virmidi_output_close, 351 .trigger = snd_virmidi_output_trigger, 352 }; 353 354 /* 355 * create a sequencer client and a port 356 */ 357 static int snd_virmidi_dev_attach_seq(struct snd_virmidi_dev *rdev) 358 { 359 int client; 360 struct snd_seq_port_callback pcallbacks; 361 struct snd_seq_port_info *pinfo; 362 int err; 363 364 if (rdev->client >= 0) 365 return 0; 366 367 pinfo = kzalloc(sizeof(*pinfo), GFP_KERNEL); 368 if (!pinfo) { 369 err = -ENOMEM; 370 goto __error; 371 } 372 373 client = snd_seq_create_kernel_client(rdev->card, rdev->device, 374 "%s %d-%d", rdev->rmidi->name, 375 rdev->card->number, 376 rdev->device); 377 if (client < 0) { 378 err = client; 379 goto __error; 380 } 381 rdev->client = client; 382 383 /* create a port */ 384 pinfo->addr.client = client; 385 sprintf(pinfo->name, "VirMIDI %d-%d", rdev->card->number, rdev->device); 386 /* set all capabilities */ 387 pinfo->capability |= SNDRV_SEQ_PORT_CAP_WRITE | SNDRV_SEQ_PORT_CAP_SYNC_WRITE | SNDRV_SEQ_PORT_CAP_SUBS_WRITE; 388 pinfo->capability |= SNDRV_SEQ_PORT_CAP_READ | SNDRV_SEQ_PORT_CAP_SYNC_READ | SNDRV_SEQ_PORT_CAP_SUBS_READ; 389 pinfo->capability |= SNDRV_SEQ_PORT_CAP_DUPLEX; 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 goto __error; 408 } 409 410 rdev->port = pinfo->addr.port; 411 err = 0; /* success */ 412 413 __error: 414 kfree(pinfo); 415 return err; 416 } 417 418 419 /* 420 * release the sequencer client 421 */ 422 static void snd_virmidi_dev_detach_seq(struct snd_virmidi_dev *rdev) 423 { 424 if (rdev->client >= 0) { 425 snd_seq_delete_kernel_client(rdev->client); 426 rdev->client = -1; 427 } 428 } 429 430 /* 431 * register the device 432 */ 433 static int snd_virmidi_dev_register(struct snd_rawmidi *rmidi) 434 { 435 struct snd_virmidi_dev *rdev = rmidi->private_data; 436 int err; 437 438 switch (rdev->seq_mode) { 439 case SNDRV_VIRMIDI_SEQ_DISPATCH: 440 err = snd_virmidi_dev_attach_seq(rdev); 441 if (err < 0) 442 return err; 443 break; 444 case SNDRV_VIRMIDI_SEQ_ATTACH: 445 if (rdev->client == 0) 446 return -EINVAL; 447 /* should check presence of port more strictly.. */ 448 break; 449 default: 450 pr_err("ALSA: seq_virmidi: seq_mode is not set: %d\n", rdev->seq_mode); 451 return -EINVAL; 452 } 453 return 0; 454 } 455 456 457 /* 458 * unregister the device 459 */ 460 static int snd_virmidi_dev_unregister(struct snd_rawmidi *rmidi) 461 { 462 struct snd_virmidi_dev *rdev = rmidi->private_data; 463 464 if (rdev->seq_mode == SNDRV_VIRMIDI_SEQ_DISPATCH) 465 snd_virmidi_dev_detach_seq(rdev); 466 return 0; 467 } 468 469 /* 470 * 471 */ 472 static const struct snd_rawmidi_global_ops snd_virmidi_global_ops = { 473 .dev_register = snd_virmidi_dev_register, 474 .dev_unregister = snd_virmidi_dev_unregister, 475 }; 476 477 /* 478 * free device 479 */ 480 static void snd_virmidi_free(struct snd_rawmidi *rmidi) 481 { 482 struct snd_virmidi_dev *rdev = rmidi->private_data; 483 kfree(rdev); 484 } 485 486 /* 487 * create a new device 488 * 489 */ 490 /* exported */ 491 int snd_virmidi_new(struct snd_card *card, int device, struct snd_rawmidi **rrmidi) 492 { 493 struct snd_rawmidi *rmidi; 494 struct snd_virmidi_dev *rdev; 495 int err; 496 497 *rrmidi = NULL; 498 if ((err = snd_rawmidi_new(card, "VirMidi", device, 499 16, /* may be configurable */ 500 16, /* may be configurable */ 501 &rmidi)) < 0) 502 return err; 503 strcpy(rmidi->name, rmidi->id); 504 rdev = kzalloc(sizeof(*rdev), GFP_KERNEL); 505 if (rdev == NULL) { 506 snd_device_free(card, rmidi); 507 return -ENOMEM; 508 } 509 rdev->card = card; 510 rdev->rmidi = rmidi; 511 rdev->device = device; 512 rdev->client = -1; 513 init_rwsem(&rdev->filelist_sem); 514 rwlock_init(&rdev->filelist_lock); 515 INIT_LIST_HEAD(&rdev->filelist); 516 rdev->seq_mode = SNDRV_VIRMIDI_SEQ_DISPATCH; 517 rmidi->private_data = rdev; 518 rmidi->private_free = snd_virmidi_free; 519 rmidi->ops = &snd_virmidi_global_ops; 520 snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_INPUT, &snd_virmidi_input_ops); 521 snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_OUTPUT, &snd_virmidi_output_ops); 522 rmidi->info_flags = SNDRV_RAWMIDI_INFO_INPUT | 523 SNDRV_RAWMIDI_INFO_OUTPUT | 524 SNDRV_RAWMIDI_INFO_DUPLEX; 525 *rrmidi = rmidi; 526 return 0; 527 } 528 EXPORT_SYMBOL(snd_virmidi_new); 529