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 char buf[32]; 153 while (snd_rawmidi_transmit(substream, buf, sizeof(buf)) > 0) 154 ; /* ignored */ 155 return; 156 } 157 158 while (READ_ONCE(vmidi->trigger)) { 159 if (snd_rawmidi_transmit(substream, &input, 1) != 1) 160 break; 161 if (!snd_midi_event_encode_byte(vmidi->parser, input, 162 &vmidi->event)) 163 continue; 164 if (vmidi->event.type != SNDRV_SEQ_EVENT_NONE) { 165 ret = snd_seq_kernel_client_dispatch(vmidi->client, 166 &vmidi->event, 167 false, 0); 168 vmidi->event.type = SNDRV_SEQ_EVENT_NONE; 169 if (ret < 0) 170 break; 171 } 172 /* rawmidi input might be huge, allow to have a break */ 173 cond_resched(); 174 } 175 } 176 177 /* 178 * trigger rawmidi stream for output 179 */ 180 static void snd_virmidi_output_trigger(struct snd_rawmidi_substream *substream, int up) 181 { 182 struct snd_virmidi *vmidi = substream->runtime->private_data; 183 184 WRITE_ONCE(vmidi->trigger, !!up); 185 if (up) 186 queue_work(system_highpri_wq, &vmidi->output_work); 187 } 188 189 /* 190 * open rawmidi handle for input 191 */ 192 static int snd_virmidi_input_open(struct snd_rawmidi_substream *substream) 193 { 194 struct snd_virmidi_dev *rdev = substream->rmidi->private_data; 195 struct snd_rawmidi_runtime *runtime = substream->runtime; 196 struct snd_virmidi *vmidi; 197 198 vmidi = kzalloc(sizeof(*vmidi), GFP_KERNEL); 199 if (vmidi == NULL) 200 return -ENOMEM; 201 vmidi->substream = substream; 202 if (snd_midi_event_new(0, &vmidi->parser) < 0) { 203 kfree(vmidi); 204 return -ENOMEM; 205 } 206 vmidi->seq_mode = rdev->seq_mode; 207 vmidi->client = rdev->client; 208 vmidi->port = rdev->port; 209 runtime->private_data = vmidi; 210 down_write(&rdev->filelist_sem); 211 write_lock_irq(&rdev->filelist_lock); 212 list_add_tail(&vmidi->list, &rdev->filelist); 213 write_unlock_irq(&rdev->filelist_lock); 214 up_write(&rdev->filelist_sem); 215 vmidi->rdev = rdev; 216 return 0; 217 } 218 219 /* 220 * open rawmidi handle for output 221 */ 222 static int snd_virmidi_output_open(struct snd_rawmidi_substream *substream) 223 { 224 struct snd_virmidi_dev *rdev = substream->rmidi->private_data; 225 struct snd_rawmidi_runtime *runtime = substream->runtime; 226 struct snd_virmidi *vmidi; 227 228 vmidi = kzalloc(sizeof(*vmidi), GFP_KERNEL); 229 if (vmidi == NULL) 230 return -ENOMEM; 231 vmidi->substream = substream; 232 if (snd_midi_event_new(MAX_MIDI_EVENT_BUF, &vmidi->parser) < 0) { 233 kfree(vmidi); 234 return -ENOMEM; 235 } 236 vmidi->seq_mode = rdev->seq_mode; 237 vmidi->client = rdev->client; 238 vmidi->port = rdev->port; 239 snd_virmidi_init_event(vmidi, &vmidi->event); 240 vmidi->rdev = rdev; 241 INIT_WORK(&vmidi->output_work, snd_vmidi_output_work); 242 runtime->private_data = vmidi; 243 return 0; 244 } 245 246 /* 247 * close rawmidi handle for input 248 */ 249 static int snd_virmidi_input_close(struct snd_rawmidi_substream *substream) 250 { 251 struct snd_virmidi_dev *rdev = substream->rmidi->private_data; 252 struct snd_virmidi *vmidi = substream->runtime->private_data; 253 254 down_write(&rdev->filelist_sem); 255 write_lock_irq(&rdev->filelist_lock); 256 list_del(&vmidi->list); 257 write_unlock_irq(&rdev->filelist_lock); 258 up_write(&rdev->filelist_sem); 259 snd_midi_event_free(vmidi->parser); 260 substream->runtime->private_data = NULL; 261 kfree(vmidi); 262 return 0; 263 } 264 265 /* 266 * close rawmidi handle for output 267 */ 268 static int snd_virmidi_output_close(struct snd_rawmidi_substream *substream) 269 { 270 struct snd_virmidi *vmidi = substream->runtime->private_data; 271 272 WRITE_ONCE(vmidi->trigger, false); /* to be sure */ 273 cancel_work_sync(&vmidi->output_work); 274 snd_midi_event_free(vmidi->parser); 275 substream->runtime->private_data = NULL; 276 kfree(vmidi); 277 return 0; 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(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(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(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(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 }; 355 356 /* 357 * create a sequencer client and a port 358 */ 359 static int snd_virmidi_dev_attach_seq(struct snd_virmidi_dev *rdev) 360 { 361 int client; 362 struct snd_seq_port_callback pcallbacks; 363 struct snd_seq_port_info *pinfo; 364 int err; 365 366 if (rdev->client >= 0) 367 return 0; 368 369 pinfo = kzalloc(sizeof(*pinfo), GFP_KERNEL); 370 if (!pinfo) { 371 err = -ENOMEM; 372 goto __error; 373 } 374 375 client = snd_seq_create_kernel_client(rdev->card, rdev->device, 376 "%s %d-%d", rdev->rmidi->name, 377 rdev->card->number, 378 rdev->device); 379 if (client < 0) { 380 err = client; 381 goto __error; 382 } 383 rdev->client = client; 384 385 /* create a port */ 386 pinfo->addr.client = client; 387 sprintf(pinfo->name, "VirMIDI %d-%d", rdev->card->number, rdev->device); 388 /* set all capabilities */ 389 pinfo->capability |= SNDRV_SEQ_PORT_CAP_WRITE | SNDRV_SEQ_PORT_CAP_SYNC_WRITE | SNDRV_SEQ_PORT_CAP_SUBS_WRITE; 390 pinfo->capability |= SNDRV_SEQ_PORT_CAP_READ | SNDRV_SEQ_PORT_CAP_SYNC_READ | SNDRV_SEQ_PORT_CAP_SUBS_READ; 391 pinfo->capability |= SNDRV_SEQ_PORT_CAP_DUPLEX; 392 pinfo->type = SNDRV_SEQ_PORT_TYPE_MIDI_GENERIC 393 | SNDRV_SEQ_PORT_TYPE_SOFTWARE 394 | SNDRV_SEQ_PORT_TYPE_PORT; 395 pinfo->midi_channels = 16; 396 memset(&pcallbacks, 0, sizeof(pcallbacks)); 397 pcallbacks.owner = THIS_MODULE; 398 pcallbacks.private_data = rdev; 399 pcallbacks.subscribe = snd_virmidi_subscribe; 400 pcallbacks.unsubscribe = snd_virmidi_unsubscribe; 401 pcallbacks.use = snd_virmidi_use; 402 pcallbacks.unuse = snd_virmidi_unuse; 403 pcallbacks.event_input = snd_virmidi_event_input; 404 pinfo->kernel = &pcallbacks; 405 err = snd_seq_kernel_client_ctl(client, SNDRV_SEQ_IOCTL_CREATE_PORT, pinfo); 406 if (err < 0) { 407 snd_seq_delete_kernel_client(client); 408 rdev->client = -1; 409 goto __error; 410 } 411 412 rdev->port = pinfo->addr.port; 413 err = 0; /* success */ 414 415 __error: 416 kfree(pinfo); 417 return err; 418 } 419 420 421 /* 422 * release the sequencer client 423 */ 424 static void snd_virmidi_dev_detach_seq(struct snd_virmidi_dev *rdev) 425 { 426 if (rdev->client >= 0) { 427 snd_seq_delete_kernel_client(rdev->client); 428 rdev->client = -1; 429 } 430 } 431 432 /* 433 * register the device 434 */ 435 static int snd_virmidi_dev_register(struct snd_rawmidi *rmidi) 436 { 437 struct snd_virmidi_dev *rdev = rmidi->private_data; 438 int err; 439 440 switch (rdev->seq_mode) { 441 case SNDRV_VIRMIDI_SEQ_DISPATCH: 442 err = snd_virmidi_dev_attach_seq(rdev); 443 if (err < 0) 444 return err; 445 break; 446 case SNDRV_VIRMIDI_SEQ_ATTACH: 447 if (rdev->client == 0) 448 return -EINVAL; 449 /* should check presence of port more strictly.. */ 450 break; 451 default: 452 pr_err("ALSA: seq_virmidi: seq_mode is not set: %d\n", rdev->seq_mode); 453 return -EINVAL; 454 } 455 return 0; 456 } 457 458 459 /* 460 * unregister the device 461 */ 462 static int snd_virmidi_dev_unregister(struct snd_rawmidi *rmidi) 463 { 464 struct snd_virmidi_dev *rdev = rmidi->private_data; 465 466 if (rdev->seq_mode == SNDRV_VIRMIDI_SEQ_DISPATCH) 467 snd_virmidi_dev_detach_seq(rdev); 468 return 0; 469 } 470 471 /* 472 * 473 */ 474 static const struct snd_rawmidi_global_ops snd_virmidi_global_ops = { 475 .dev_register = snd_virmidi_dev_register, 476 .dev_unregister = snd_virmidi_dev_unregister, 477 }; 478 479 /* 480 * free device 481 */ 482 static void snd_virmidi_free(struct snd_rawmidi *rmidi) 483 { 484 struct snd_virmidi_dev *rdev = rmidi->private_data; 485 kfree(rdev); 486 } 487 488 /* 489 * create a new device 490 * 491 */ 492 /* exported */ 493 int snd_virmidi_new(struct snd_card *card, int device, struct snd_rawmidi **rrmidi) 494 { 495 struct snd_rawmidi *rmidi; 496 struct snd_virmidi_dev *rdev; 497 int err; 498 499 *rrmidi = NULL; 500 if ((err = snd_rawmidi_new(card, "VirMidi", device, 501 16, /* may be configurable */ 502 16, /* may be configurable */ 503 &rmidi)) < 0) 504 return err; 505 strcpy(rmidi->name, rmidi->id); 506 rdev = kzalloc(sizeof(*rdev), GFP_KERNEL); 507 if (rdev == NULL) { 508 snd_device_free(card, rmidi); 509 return -ENOMEM; 510 } 511 rdev->card = card; 512 rdev->rmidi = rmidi; 513 rdev->device = device; 514 rdev->client = -1; 515 init_rwsem(&rdev->filelist_sem); 516 rwlock_init(&rdev->filelist_lock); 517 INIT_LIST_HEAD(&rdev->filelist); 518 rdev->seq_mode = SNDRV_VIRMIDI_SEQ_DISPATCH; 519 rmidi->private_data = rdev; 520 rmidi->private_free = snd_virmidi_free; 521 rmidi->ops = &snd_virmidi_global_ops; 522 snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_INPUT, &snd_virmidi_input_ops); 523 snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_OUTPUT, &snd_virmidi_output_ops); 524 rmidi->info_flags = SNDRV_RAWMIDI_INFO_INPUT | 525 SNDRV_RAWMIDI_INFO_OUTPUT | 526 SNDRV_RAWMIDI_INFO_DUPLEX; 527 *rrmidi = rmidi; 528 return 0; 529 } 530 EXPORT_SYMBOL(snd_virmidi_new); 531