1 /* 2 * Loopback soundcard 3 * 4 * Original code: 5 * Copyright (c) by Jaroslav Kysela <perex@perex.cz> 6 * 7 * More accurate positioning and full-duplex support: 8 * Copyright (c) Ahmet İnan <ainan at mathematik.uni-freiburg.de> 9 * 10 * Major (almost complete) rewrite: 11 * Copyright (c) by Takashi Iwai <tiwai@suse.de> 12 * 13 * A next major update in 2010 (separate timers for playback and capture): 14 * Copyright (c) Jaroslav Kysela <perex@perex.cz> 15 * 16 * This program is free software; you can redistribute it and/or modify 17 * it under the terms of the GNU General Public License as published by 18 * the Free Software Foundation; either version 2 of the License, or 19 * (at your option) any later version. 20 * 21 * This program is distributed in the hope that it will be useful, 22 * but WITHOUT ANY WARRANTY; without even the implied warranty of 23 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 24 * GNU General Public License for more details. 25 * 26 * You should have received a copy of the GNU General Public License 27 * along with this program; if not, write to the Free Software 28 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 29 * 30 */ 31 32 #include <linux/init.h> 33 #include <linux/jiffies.h> 34 #include <linux/slab.h> 35 #include <linux/time.h> 36 #include <linux/wait.h> 37 #include <linux/module.h> 38 #include <linux/platform_device.h> 39 #include <sound/core.h> 40 #include <sound/control.h> 41 #include <sound/pcm.h> 42 #include <sound/info.h> 43 #include <sound/initval.h> 44 45 MODULE_AUTHOR("Jaroslav Kysela <perex@perex.cz>"); 46 MODULE_DESCRIPTION("A loopback soundcard"); 47 MODULE_LICENSE("GPL"); 48 MODULE_SUPPORTED_DEVICE("{{ALSA,Loopback soundcard}}"); 49 50 #define MAX_PCM_SUBSTREAMS 8 51 52 static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX; /* Index 0-MAX */ 53 static char *id[SNDRV_CARDS] = SNDRV_DEFAULT_STR; /* ID for this card */ 54 static int enable[SNDRV_CARDS] = {1, [1 ... (SNDRV_CARDS - 1)] = 0}; 55 static int pcm_substreams[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 8}; 56 static int pcm_notify[SNDRV_CARDS]; 57 58 module_param_array(index, int, NULL, 0444); 59 MODULE_PARM_DESC(index, "Index value for loopback soundcard."); 60 module_param_array(id, charp, NULL, 0444); 61 MODULE_PARM_DESC(id, "ID string for loopback soundcard."); 62 module_param_array(enable, bool, NULL, 0444); 63 MODULE_PARM_DESC(enable, "Enable this loopback soundcard."); 64 module_param_array(pcm_substreams, int, NULL, 0444); 65 MODULE_PARM_DESC(pcm_substreams, "PCM substreams # (1-8) for loopback driver."); 66 module_param_array(pcm_notify, int, NULL, 0444); 67 MODULE_PARM_DESC(pcm_notify, "Break capture when PCM format/rate/channels changes."); 68 69 #define NO_PITCH 100000 70 71 struct loopback_pcm; 72 73 struct loopback_cable { 74 spinlock_t lock; 75 struct loopback_pcm *streams[2]; 76 struct snd_pcm_hardware hw; 77 /* flags */ 78 unsigned int valid; 79 unsigned int running; 80 unsigned int pause; 81 }; 82 83 struct loopback_setup { 84 unsigned int notify: 1; 85 unsigned int rate_shift; 86 unsigned int format; 87 unsigned int rate; 88 unsigned int channels; 89 struct snd_ctl_elem_id active_id; 90 struct snd_ctl_elem_id format_id; 91 struct snd_ctl_elem_id rate_id; 92 struct snd_ctl_elem_id channels_id; 93 }; 94 95 struct loopback { 96 struct snd_card *card; 97 struct mutex cable_lock; 98 struct loopback_cable *cables[MAX_PCM_SUBSTREAMS][2]; 99 struct snd_pcm *pcm[2]; 100 struct loopback_setup setup[MAX_PCM_SUBSTREAMS][2]; 101 }; 102 103 struct loopback_pcm { 104 struct loopback *loopback; 105 struct snd_pcm_substream *substream; 106 struct loopback_cable *cable; 107 unsigned int pcm_buffer_size; 108 unsigned int buf_pos; /* position in buffer */ 109 unsigned int silent_size; 110 /* PCM parameters */ 111 unsigned int pcm_period_size; 112 unsigned int pcm_bps; /* bytes per second */ 113 unsigned int pcm_salign; /* bytes per sample * channels */ 114 unsigned int pcm_rate_shift; /* rate shift value */ 115 /* flags */ 116 unsigned int period_update_pending :1; 117 /* timer stuff */ 118 unsigned int irq_pos; /* fractional IRQ position */ 119 unsigned int period_size_frac; 120 unsigned long last_jiffies; 121 struct timer_list timer; 122 }; 123 124 static struct platform_device *devices[SNDRV_CARDS]; 125 126 static inline unsigned int byte_pos(struct loopback_pcm *dpcm, unsigned int x) 127 { 128 if (dpcm->pcm_rate_shift == NO_PITCH) { 129 x /= HZ; 130 } else { 131 x = div_u64(NO_PITCH * (unsigned long long)x, 132 HZ * (unsigned long long)dpcm->pcm_rate_shift); 133 } 134 return x - (x % dpcm->pcm_salign); 135 } 136 137 static inline unsigned int frac_pos(struct loopback_pcm *dpcm, unsigned int x) 138 { 139 if (dpcm->pcm_rate_shift == NO_PITCH) { /* no pitch */ 140 return x * HZ; 141 } else { 142 x = div_u64(dpcm->pcm_rate_shift * (unsigned long long)x * HZ, 143 NO_PITCH); 144 } 145 return x; 146 } 147 148 static inline struct loopback_setup *get_setup(struct loopback_pcm *dpcm) 149 { 150 int device = dpcm->substream->pstr->pcm->device; 151 152 if (dpcm->substream->stream == SNDRV_PCM_STREAM_PLAYBACK) 153 device ^= 1; 154 return &dpcm->loopback->setup[dpcm->substream->number][device]; 155 } 156 157 static inline unsigned int get_notify(struct loopback_pcm *dpcm) 158 { 159 return get_setup(dpcm)->notify; 160 } 161 162 static inline unsigned int get_rate_shift(struct loopback_pcm *dpcm) 163 { 164 return get_setup(dpcm)->rate_shift; 165 } 166 167 static void loopback_timer_start(struct loopback_pcm *dpcm) 168 { 169 unsigned long tick; 170 unsigned int rate_shift = get_rate_shift(dpcm); 171 172 if (rate_shift != dpcm->pcm_rate_shift) { 173 dpcm->pcm_rate_shift = rate_shift; 174 dpcm->period_size_frac = frac_pos(dpcm, dpcm->pcm_period_size); 175 } 176 if (dpcm->period_size_frac <= dpcm->irq_pos) { 177 dpcm->irq_pos %= dpcm->period_size_frac; 178 dpcm->period_update_pending = 1; 179 } 180 tick = dpcm->period_size_frac - dpcm->irq_pos; 181 tick = (tick + dpcm->pcm_bps - 1) / dpcm->pcm_bps; 182 dpcm->timer.expires = jiffies + tick; 183 add_timer(&dpcm->timer); 184 } 185 186 static inline void loopback_timer_stop(struct loopback_pcm *dpcm) 187 { 188 del_timer(&dpcm->timer); 189 dpcm->timer.expires = 0; 190 } 191 192 #define CABLE_VALID_PLAYBACK (1 << SNDRV_PCM_STREAM_PLAYBACK) 193 #define CABLE_VALID_CAPTURE (1 << SNDRV_PCM_STREAM_CAPTURE) 194 #define CABLE_VALID_BOTH (CABLE_VALID_PLAYBACK|CABLE_VALID_CAPTURE) 195 196 static int loopback_check_format(struct loopback_cable *cable, int stream) 197 { 198 struct snd_pcm_runtime *runtime, *cruntime; 199 struct loopback_setup *setup; 200 struct snd_card *card; 201 int check; 202 203 if (cable->valid != CABLE_VALID_BOTH) { 204 if (stream == SNDRV_PCM_STREAM_PLAYBACK) 205 goto __notify; 206 return 0; 207 } 208 runtime = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]-> 209 substream->runtime; 210 cruntime = cable->streams[SNDRV_PCM_STREAM_CAPTURE]-> 211 substream->runtime; 212 check = runtime->format != cruntime->format || 213 runtime->rate != cruntime->rate || 214 runtime->channels != cruntime->channels; 215 if (!check) 216 return 0; 217 if (stream == SNDRV_PCM_STREAM_CAPTURE) { 218 return -EIO; 219 } else { 220 snd_pcm_stop(cable->streams[SNDRV_PCM_STREAM_CAPTURE]-> 221 substream, SNDRV_PCM_STATE_DRAINING); 222 __notify: 223 runtime = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]-> 224 substream->runtime; 225 setup = get_setup(cable->streams[SNDRV_PCM_STREAM_PLAYBACK]); 226 card = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]->loopback->card; 227 if (setup->format != runtime->format) { 228 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE, 229 &setup->format_id); 230 setup->format = runtime->format; 231 } 232 if (setup->rate != runtime->rate) { 233 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE, 234 &setup->rate_id); 235 setup->rate = runtime->rate; 236 } 237 if (setup->channels != runtime->channels) { 238 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE, 239 &setup->channels_id); 240 setup->channels = runtime->channels; 241 } 242 } 243 return 0; 244 } 245 246 static void loopback_active_notify(struct loopback_pcm *dpcm) 247 { 248 snd_ctl_notify(dpcm->loopback->card, 249 SNDRV_CTL_EVENT_MASK_VALUE, 250 &get_setup(dpcm)->active_id); 251 } 252 253 static int loopback_trigger(struct snd_pcm_substream *substream, int cmd) 254 { 255 struct snd_pcm_runtime *runtime = substream->runtime; 256 struct loopback_pcm *dpcm = runtime->private_data; 257 struct loopback_cable *cable = dpcm->cable; 258 int err, stream = 1 << substream->stream; 259 260 switch (cmd) { 261 case SNDRV_PCM_TRIGGER_START: 262 err = loopback_check_format(cable, substream->stream); 263 if (err < 0) 264 return err; 265 dpcm->last_jiffies = jiffies; 266 dpcm->pcm_rate_shift = 0; 267 spin_lock(&cable->lock); 268 cable->running |= stream; 269 cable->pause &= ~stream; 270 spin_unlock(&cable->lock); 271 loopback_timer_start(dpcm); 272 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) 273 loopback_active_notify(dpcm); 274 break; 275 case SNDRV_PCM_TRIGGER_STOP: 276 spin_lock(&cable->lock); 277 cable->running &= ~stream; 278 cable->pause &= ~stream; 279 spin_unlock(&cable->lock); 280 loopback_timer_stop(dpcm); 281 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) 282 loopback_active_notify(dpcm); 283 break; 284 case SNDRV_PCM_TRIGGER_PAUSE_PUSH: 285 spin_lock(&cable->lock); 286 cable->pause |= stream; 287 spin_unlock(&cable->lock); 288 loopback_timer_stop(dpcm); 289 break; 290 case SNDRV_PCM_TRIGGER_PAUSE_RELEASE: 291 spin_lock(&cable->lock); 292 dpcm->last_jiffies = jiffies; 293 cable->pause &= ~stream; 294 spin_unlock(&cable->lock); 295 loopback_timer_start(dpcm); 296 break; 297 default: 298 return -EINVAL; 299 } 300 return 0; 301 } 302 303 static void params_change_substream(struct loopback_pcm *dpcm, 304 struct snd_pcm_runtime *runtime) 305 { 306 struct snd_pcm_runtime *dst_runtime; 307 308 if (dpcm == NULL || dpcm->substream == NULL) 309 return; 310 dst_runtime = dpcm->substream->runtime; 311 if (dst_runtime == NULL) 312 return; 313 dst_runtime->hw = dpcm->cable->hw; 314 } 315 316 static void params_change(struct snd_pcm_substream *substream) 317 { 318 struct snd_pcm_runtime *runtime = substream->runtime; 319 struct loopback_pcm *dpcm = runtime->private_data; 320 struct loopback_cable *cable = dpcm->cable; 321 322 cable->hw.formats = (1ULL << runtime->format); 323 cable->hw.rate_min = runtime->rate; 324 cable->hw.rate_max = runtime->rate; 325 cable->hw.channels_min = runtime->channels; 326 cable->hw.channels_max = runtime->channels; 327 params_change_substream(cable->streams[SNDRV_PCM_STREAM_PLAYBACK], 328 runtime); 329 params_change_substream(cable->streams[SNDRV_PCM_STREAM_CAPTURE], 330 runtime); 331 } 332 333 static int loopback_prepare(struct snd_pcm_substream *substream) 334 { 335 struct snd_pcm_runtime *runtime = substream->runtime; 336 struct loopback_pcm *dpcm = runtime->private_data; 337 struct loopback_cable *cable = dpcm->cable; 338 int bps, salign; 339 340 salign = (snd_pcm_format_width(runtime->format) * 341 runtime->channels) / 8; 342 bps = salign * runtime->rate; 343 if (bps <= 0 || salign <= 0) 344 return -EINVAL; 345 346 dpcm->buf_pos = 0; 347 dpcm->pcm_buffer_size = frames_to_bytes(runtime, runtime->buffer_size); 348 if (substream->stream == SNDRV_PCM_STREAM_CAPTURE) { 349 /* clear capture buffer */ 350 dpcm->silent_size = dpcm->pcm_buffer_size; 351 snd_pcm_format_set_silence(runtime->format, runtime->dma_area, 352 runtime->buffer_size * runtime->channels); 353 } 354 355 dpcm->irq_pos = 0; 356 dpcm->period_update_pending = 0; 357 dpcm->pcm_bps = bps; 358 dpcm->pcm_salign = salign; 359 dpcm->pcm_period_size = frames_to_bytes(runtime, runtime->period_size); 360 361 mutex_lock(&dpcm->loopback->cable_lock); 362 if (!(cable->valid & ~(1 << substream->stream)) || 363 (get_setup(dpcm)->notify && 364 substream->stream == SNDRV_PCM_STREAM_PLAYBACK)) 365 params_change(substream); 366 cable->valid |= 1 << substream->stream; 367 mutex_unlock(&dpcm->loopback->cable_lock); 368 369 return 0; 370 } 371 372 static void clear_capture_buf(struct loopback_pcm *dpcm, unsigned int bytes) 373 { 374 struct snd_pcm_runtime *runtime = dpcm->substream->runtime; 375 char *dst = runtime->dma_area; 376 unsigned int dst_off = dpcm->buf_pos; 377 378 if (dpcm->silent_size >= dpcm->pcm_buffer_size) 379 return; 380 if (dpcm->silent_size + bytes > dpcm->pcm_buffer_size) 381 bytes = dpcm->pcm_buffer_size - dpcm->silent_size; 382 383 for (;;) { 384 unsigned int size = bytes; 385 if (dst_off + size > dpcm->pcm_buffer_size) 386 size = dpcm->pcm_buffer_size - dst_off; 387 snd_pcm_format_set_silence(runtime->format, dst + dst_off, 388 bytes_to_frames(runtime, size) * 389 runtime->channels); 390 dpcm->silent_size += size; 391 bytes -= size; 392 if (!bytes) 393 break; 394 dst_off = 0; 395 } 396 } 397 398 static void copy_play_buf(struct loopback_pcm *play, 399 struct loopback_pcm *capt, 400 unsigned int bytes) 401 { 402 struct snd_pcm_runtime *runtime = play->substream->runtime; 403 char *src = runtime->dma_area; 404 char *dst = capt->substream->runtime->dma_area; 405 unsigned int src_off = play->buf_pos; 406 unsigned int dst_off = capt->buf_pos; 407 unsigned int clear_bytes = 0; 408 409 /* check if playback is draining, trim the capture copy size 410 * when our pointer is at the end of playback ring buffer */ 411 if (runtime->status->state == SNDRV_PCM_STATE_DRAINING && 412 snd_pcm_playback_hw_avail(runtime) < runtime->buffer_size) { 413 snd_pcm_uframes_t appl_ptr, appl_ptr1, diff; 414 appl_ptr = appl_ptr1 = runtime->control->appl_ptr; 415 appl_ptr1 -= appl_ptr1 % runtime->buffer_size; 416 appl_ptr1 += play->buf_pos / play->pcm_salign; 417 if (appl_ptr < appl_ptr1) 418 appl_ptr1 -= runtime->buffer_size; 419 diff = (appl_ptr - appl_ptr1) * play->pcm_salign; 420 if (diff < bytes) { 421 clear_bytes = bytes - diff; 422 bytes = diff; 423 } 424 } 425 426 for (;;) { 427 unsigned int size = bytes; 428 if (src_off + size > play->pcm_buffer_size) 429 size = play->pcm_buffer_size - src_off; 430 if (dst_off + size > capt->pcm_buffer_size) 431 size = capt->pcm_buffer_size - dst_off; 432 memcpy(dst + dst_off, src + src_off, size); 433 capt->silent_size = 0; 434 bytes -= size; 435 if (!bytes) 436 break; 437 src_off = (src_off + size) % play->pcm_buffer_size; 438 dst_off = (dst_off + size) % capt->pcm_buffer_size; 439 } 440 441 if (clear_bytes > 0) { 442 clear_capture_buf(capt, clear_bytes); 443 capt->silent_size = 0; 444 } 445 } 446 447 #define BYTEPOS_UPDATE_POSONLY 0 448 #define BYTEPOS_UPDATE_CLEAR 1 449 #define BYTEPOS_UPDATE_COPY 2 450 451 static void loopback_bytepos_update(struct loopback_pcm *dpcm, 452 unsigned int delta, 453 unsigned int cmd) 454 { 455 unsigned int count; 456 unsigned long last_pos; 457 458 last_pos = byte_pos(dpcm, dpcm->irq_pos); 459 dpcm->irq_pos += delta * dpcm->pcm_bps; 460 count = byte_pos(dpcm, dpcm->irq_pos) - last_pos; 461 if (!count) 462 return; 463 if (cmd == BYTEPOS_UPDATE_CLEAR) 464 clear_capture_buf(dpcm, count); 465 else if (cmd == BYTEPOS_UPDATE_COPY) 466 copy_play_buf(dpcm->cable->streams[SNDRV_PCM_STREAM_PLAYBACK], 467 dpcm->cable->streams[SNDRV_PCM_STREAM_CAPTURE], 468 count); 469 dpcm->buf_pos += count; 470 dpcm->buf_pos %= dpcm->pcm_buffer_size; 471 if (dpcm->irq_pos >= dpcm->period_size_frac) { 472 dpcm->irq_pos %= dpcm->period_size_frac; 473 dpcm->period_update_pending = 1; 474 } 475 } 476 477 static unsigned int loopback_pos_update(struct loopback_cable *cable) 478 { 479 struct loopback_pcm *dpcm_play = 480 cable->streams[SNDRV_PCM_STREAM_PLAYBACK]; 481 struct loopback_pcm *dpcm_capt = 482 cable->streams[SNDRV_PCM_STREAM_CAPTURE]; 483 unsigned long delta_play = 0, delta_capt = 0; 484 unsigned int running; 485 unsigned long flags; 486 487 spin_lock_irqsave(&cable->lock, flags); 488 running = cable->running ^ cable->pause; 489 if (running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) { 490 delta_play = jiffies - dpcm_play->last_jiffies; 491 dpcm_play->last_jiffies += delta_play; 492 } 493 494 if (running & (1 << SNDRV_PCM_STREAM_CAPTURE)) { 495 delta_capt = jiffies - dpcm_capt->last_jiffies; 496 dpcm_capt->last_jiffies += delta_capt; 497 } 498 499 if (delta_play == 0 && delta_capt == 0) 500 goto unlock; 501 502 if (delta_play > delta_capt) { 503 loopback_bytepos_update(dpcm_play, delta_play - delta_capt, 504 BYTEPOS_UPDATE_POSONLY); 505 delta_play = delta_capt; 506 } else if (delta_play < delta_capt) { 507 loopback_bytepos_update(dpcm_capt, delta_capt - delta_play, 508 BYTEPOS_UPDATE_CLEAR); 509 delta_capt = delta_play; 510 } 511 512 if (delta_play == 0 && delta_capt == 0) 513 goto unlock; 514 515 /* note delta_capt == delta_play at this moment */ 516 loopback_bytepos_update(dpcm_capt, delta_capt, BYTEPOS_UPDATE_COPY); 517 loopback_bytepos_update(dpcm_play, delta_play, BYTEPOS_UPDATE_POSONLY); 518 unlock: 519 spin_unlock_irqrestore(&cable->lock, flags); 520 return running; 521 } 522 523 static void loopback_timer_function(unsigned long data) 524 { 525 struct loopback_pcm *dpcm = (struct loopback_pcm *)data; 526 unsigned int running; 527 528 running = loopback_pos_update(dpcm->cable); 529 if (running & (1 << dpcm->substream->stream)) { 530 loopback_timer_start(dpcm); 531 if (dpcm->period_update_pending) { 532 dpcm->period_update_pending = 0; 533 snd_pcm_period_elapsed(dpcm->substream); 534 } 535 } 536 } 537 538 static snd_pcm_uframes_t loopback_pointer(struct snd_pcm_substream *substream) 539 { 540 struct snd_pcm_runtime *runtime = substream->runtime; 541 struct loopback_pcm *dpcm = runtime->private_data; 542 543 loopback_pos_update(dpcm->cable); 544 return bytes_to_frames(runtime, dpcm->buf_pos); 545 } 546 547 static struct snd_pcm_hardware loopback_pcm_hardware = 548 { 549 .info = (SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_MMAP | 550 SNDRV_PCM_INFO_MMAP_VALID | SNDRV_PCM_INFO_PAUSE), 551 .formats = (SNDRV_PCM_FMTBIT_S16_LE | SNDRV_PCM_FMTBIT_S16_BE | 552 SNDRV_PCM_FMTBIT_S32_LE | SNDRV_PCM_FMTBIT_S32_BE | 553 SNDRV_PCM_FMTBIT_FLOAT_LE | SNDRV_PCM_FMTBIT_FLOAT_BE), 554 .rates = SNDRV_PCM_RATE_CONTINUOUS | SNDRV_PCM_RATE_8000_192000, 555 .rate_min = 8000, 556 .rate_max = 192000, 557 .channels_min = 1, 558 .channels_max = 32, 559 .buffer_bytes_max = 2 * 1024 * 1024, 560 .period_bytes_min = 64, 561 /* note check overflow in frac_pos() using pcm_rate_shift before 562 changing period_bytes_max value */ 563 .period_bytes_max = 1024 * 1024, 564 .periods_min = 1, 565 .periods_max = 1024, 566 .fifo_size = 0, 567 }; 568 569 static void loopback_runtime_free(struct snd_pcm_runtime *runtime) 570 { 571 struct loopback_pcm *dpcm = runtime->private_data; 572 kfree(dpcm); 573 } 574 575 static int loopback_hw_params(struct snd_pcm_substream *substream, 576 struct snd_pcm_hw_params *params) 577 { 578 return snd_pcm_lib_alloc_vmalloc_buffer(substream, 579 params_buffer_bytes(params)); 580 } 581 582 static int loopback_hw_free(struct snd_pcm_substream *substream) 583 { 584 struct snd_pcm_runtime *runtime = substream->runtime; 585 struct loopback_pcm *dpcm = runtime->private_data; 586 struct loopback_cable *cable = dpcm->cable; 587 588 mutex_lock(&dpcm->loopback->cable_lock); 589 cable->valid &= ~(1 << substream->stream); 590 mutex_unlock(&dpcm->loopback->cable_lock); 591 return snd_pcm_lib_free_vmalloc_buffer(substream); 592 } 593 594 static unsigned int get_cable_index(struct snd_pcm_substream *substream) 595 { 596 if (!substream->pcm->device) 597 return substream->stream; 598 else 599 return !substream->stream; 600 } 601 602 static int rule_format(struct snd_pcm_hw_params *params, 603 struct snd_pcm_hw_rule *rule) 604 { 605 606 struct snd_pcm_hardware *hw = rule->private; 607 struct snd_mask *maskp = hw_param_mask(params, rule->var); 608 609 maskp->bits[0] &= (u_int32_t)hw->formats; 610 maskp->bits[1] &= (u_int32_t)(hw->formats >> 32); 611 memset(maskp->bits + 2, 0, (SNDRV_MASK_MAX-64) / 8); /* clear rest */ 612 if (! maskp->bits[0] && ! maskp->bits[1]) 613 return -EINVAL; 614 return 0; 615 } 616 617 static int rule_rate(struct snd_pcm_hw_params *params, 618 struct snd_pcm_hw_rule *rule) 619 { 620 struct snd_pcm_hardware *hw = rule->private; 621 struct snd_interval t; 622 623 t.min = hw->rate_min; 624 t.max = hw->rate_max; 625 t.openmin = t.openmax = 0; 626 t.integer = 0; 627 return snd_interval_refine(hw_param_interval(params, rule->var), &t); 628 } 629 630 static int rule_channels(struct snd_pcm_hw_params *params, 631 struct snd_pcm_hw_rule *rule) 632 { 633 struct snd_pcm_hardware *hw = rule->private; 634 struct snd_interval t; 635 636 t.min = hw->channels_min; 637 t.max = hw->channels_max; 638 t.openmin = t.openmax = 0; 639 t.integer = 0; 640 return snd_interval_refine(hw_param_interval(params, rule->var), &t); 641 } 642 643 static int loopback_open(struct snd_pcm_substream *substream) 644 { 645 struct snd_pcm_runtime *runtime = substream->runtime; 646 struct loopback *loopback = substream->private_data; 647 struct loopback_pcm *dpcm; 648 struct loopback_cable *cable; 649 int err = 0; 650 int dev = get_cable_index(substream); 651 652 mutex_lock(&loopback->cable_lock); 653 dpcm = kzalloc(sizeof(*dpcm), GFP_KERNEL); 654 if (!dpcm) { 655 err = -ENOMEM; 656 goto unlock; 657 } 658 dpcm->loopback = loopback; 659 dpcm->substream = substream; 660 setup_timer(&dpcm->timer, loopback_timer_function, 661 (unsigned long)dpcm); 662 663 cable = loopback->cables[substream->number][dev]; 664 if (!cable) { 665 cable = kzalloc(sizeof(*cable), GFP_KERNEL); 666 if (!cable) { 667 kfree(dpcm); 668 err = -ENOMEM; 669 goto unlock; 670 } 671 spin_lock_init(&cable->lock); 672 cable->hw = loopback_pcm_hardware; 673 loopback->cables[substream->number][dev] = cable; 674 } 675 dpcm->cable = cable; 676 cable->streams[substream->stream] = dpcm; 677 678 snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS); 679 680 /* use dynamic rules based on actual runtime->hw values */ 681 /* note that the default rules created in the PCM midlevel code */ 682 /* are cached -> they do not reflect the actual state */ 683 err = snd_pcm_hw_rule_add(runtime, 0, 684 SNDRV_PCM_HW_PARAM_FORMAT, 685 rule_format, &runtime->hw, 686 SNDRV_PCM_HW_PARAM_FORMAT, -1); 687 if (err < 0) 688 goto unlock; 689 err = snd_pcm_hw_rule_add(runtime, 0, 690 SNDRV_PCM_HW_PARAM_RATE, 691 rule_rate, &runtime->hw, 692 SNDRV_PCM_HW_PARAM_RATE, -1); 693 if (err < 0) 694 goto unlock; 695 err = snd_pcm_hw_rule_add(runtime, 0, 696 SNDRV_PCM_HW_PARAM_CHANNELS, 697 rule_channels, &runtime->hw, 698 SNDRV_PCM_HW_PARAM_CHANNELS, -1); 699 if (err < 0) 700 goto unlock; 701 702 runtime->private_data = dpcm; 703 runtime->private_free = loopback_runtime_free; 704 if (get_notify(dpcm)) 705 runtime->hw = loopback_pcm_hardware; 706 else 707 runtime->hw = cable->hw; 708 unlock: 709 mutex_unlock(&loopback->cable_lock); 710 return err; 711 } 712 713 static int loopback_close(struct snd_pcm_substream *substream) 714 { 715 struct loopback *loopback = substream->private_data; 716 struct loopback_pcm *dpcm = substream->runtime->private_data; 717 struct loopback_cable *cable; 718 int dev = get_cable_index(substream); 719 720 loopback_timer_stop(dpcm); 721 mutex_lock(&loopback->cable_lock); 722 cable = loopback->cables[substream->number][dev]; 723 if (cable->streams[!substream->stream]) { 724 /* other stream is still alive */ 725 cable->streams[substream->stream] = NULL; 726 } else { 727 /* free the cable */ 728 loopback->cables[substream->number][dev] = NULL; 729 kfree(cable); 730 } 731 mutex_unlock(&loopback->cable_lock); 732 return 0; 733 } 734 735 static struct snd_pcm_ops loopback_playback_ops = { 736 .open = loopback_open, 737 .close = loopback_close, 738 .ioctl = snd_pcm_lib_ioctl, 739 .hw_params = loopback_hw_params, 740 .hw_free = loopback_hw_free, 741 .prepare = loopback_prepare, 742 .trigger = loopback_trigger, 743 .pointer = loopback_pointer, 744 .page = snd_pcm_lib_get_vmalloc_page, 745 .mmap = snd_pcm_lib_mmap_vmalloc, 746 }; 747 748 static struct snd_pcm_ops loopback_capture_ops = { 749 .open = loopback_open, 750 .close = loopback_close, 751 .ioctl = snd_pcm_lib_ioctl, 752 .hw_params = loopback_hw_params, 753 .hw_free = loopback_hw_free, 754 .prepare = loopback_prepare, 755 .trigger = loopback_trigger, 756 .pointer = loopback_pointer, 757 .page = snd_pcm_lib_get_vmalloc_page, 758 .mmap = snd_pcm_lib_mmap_vmalloc, 759 }; 760 761 static int __devinit loopback_pcm_new(struct loopback *loopback, 762 int device, int substreams) 763 { 764 struct snd_pcm *pcm; 765 int err; 766 767 err = snd_pcm_new(loopback->card, "Loopback PCM", device, 768 substreams, substreams, &pcm); 769 if (err < 0) 770 return err; 771 snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &loopback_playback_ops); 772 snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &loopback_capture_ops); 773 774 pcm->private_data = loopback; 775 pcm->info_flags = 0; 776 strcpy(pcm->name, "Loopback PCM"); 777 778 loopback->pcm[device] = pcm; 779 return 0; 780 } 781 782 static int loopback_rate_shift_info(struct snd_kcontrol *kcontrol, 783 struct snd_ctl_elem_info *uinfo) 784 { 785 uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER; 786 uinfo->count = 1; 787 uinfo->value.integer.min = 80000; 788 uinfo->value.integer.max = 120000; 789 uinfo->value.integer.step = 1; 790 return 0; 791 } 792 793 static int loopback_rate_shift_get(struct snd_kcontrol *kcontrol, 794 struct snd_ctl_elem_value *ucontrol) 795 { 796 struct loopback *loopback = snd_kcontrol_chip(kcontrol); 797 798 ucontrol->value.integer.value[0] = 799 loopback->setup[kcontrol->id.subdevice] 800 [kcontrol->id.device].rate_shift; 801 return 0; 802 } 803 804 static int loopback_rate_shift_put(struct snd_kcontrol *kcontrol, 805 struct snd_ctl_elem_value *ucontrol) 806 { 807 struct loopback *loopback = snd_kcontrol_chip(kcontrol); 808 unsigned int val; 809 int change = 0; 810 811 val = ucontrol->value.integer.value[0]; 812 if (val < 80000) 813 val = 80000; 814 if (val > 120000) 815 val = 120000; 816 mutex_lock(&loopback->cable_lock); 817 if (val != loopback->setup[kcontrol->id.subdevice] 818 [kcontrol->id.device].rate_shift) { 819 loopback->setup[kcontrol->id.subdevice] 820 [kcontrol->id.device].rate_shift = val; 821 change = 1; 822 } 823 mutex_unlock(&loopback->cable_lock); 824 return change; 825 } 826 827 static int loopback_notify_get(struct snd_kcontrol *kcontrol, 828 struct snd_ctl_elem_value *ucontrol) 829 { 830 struct loopback *loopback = snd_kcontrol_chip(kcontrol); 831 832 ucontrol->value.integer.value[0] = 833 loopback->setup[kcontrol->id.subdevice] 834 [kcontrol->id.device].notify; 835 return 0; 836 } 837 838 static int loopback_notify_put(struct snd_kcontrol *kcontrol, 839 struct snd_ctl_elem_value *ucontrol) 840 { 841 struct loopback *loopback = snd_kcontrol_chip(kcontrol); 842 unsigned int val; 843 int change = 0; 844 845 val = ucontrol->value.integer.value[0] ? 1 : 0; 846 if (val != loopback->setup[kcontrol->id.subdevice] 847 [kcontrol->id.device].notify) { 848 loopback->setup[kcontrol->id.subdevice] 849 [kcontrol->id.device].notify = val; 850 change = 1; 851 } 852 return change; 853 } 854 855 static int loopback_active_get(struct snd_kcontrol *kcontrol, 856 struct snd_ctl_elem_value *ucontrol) 857 { 858 struct loopback *loopback = snd_kcontrol_chip(kcontrol); 859 struct loopback_cable *cable = loopback->cables 860 [kcontrol->id.subdevice][kcontrol->id.device ^ 1]; 861 unsigned int val = 0; 862 863 if (cable != NULL) 864 val = (cable->running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) ? 865 1 : 0; 866 ucontrol->value.integer.value[0] = val; 867 return 0; 868 } 869 870 static int loopback_format_info(struct snd_kcontrol *kcontrol, 871 struct snd_ctl_elem_info *uinfo) 872 { 873 uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER; 874 uinfo->count = 1; 875 uinfo->value.integer.min = 0; 876 uinfo->value.integer.max = SNDRV_PCM_FORMAT_LAST; 877 uinfo->value.integer.step = 1; 878 return 0; 879 } 880 881 static int loopback_format_get(struct snd_kcontrol *kcontrol, 882 struct snd_ctl_elem_value *ucontrol) 883 { 884 struct loopback *loopback = snd_kcontrol_chip(kcontrol); 885 886 ucontrol->value.integer.value[0] = 887 loopback->setup[kcontrol->id.subdevice] 888 [kcontrol->id.device].format; 889 return 0; 890 } 891 892 static int loopback_rate_info(struct snd_kcontrol *kcontrol, 893 struct snd_ctl_elem_info *uinfo) 894 { 895 uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER; 896 uinfo->count = 1; 897 uinfo->value.integer.min = 0; 898 uinfo->value.integer.max = 192000; 899 uinfo->value.integer.step = 1; 900 return 0; 901 } 902 903 static int loopback_rate_get(struct snd_kcontrol *kcontrol, 904 struct snd_ctl_elem_value *ucontrol) 905 { 906 struct loopback *loopback = snd_kcontrol_chip(kcontrol); 907 908 ucontrol->value.integer.value[0] = 909 loopback->setup[kcontrol->id.subdevice] 910 [kcontrol->id.device].rate; 911 return 0; 912 } 913 914 static int loopback_channels_info(struct snd_kcontrol *kcontrol, 915 struct snd_ctl_elem_info *uinfo) 916 { 917 uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER; 918 uinfo->count = 1; 919 uinfo->value.integer.min = 1; 920 uinfo->value.integer.max = 1024; 921 uinfo->value.integer.step = 1; 922 return 0; 923 } 924 925 static int loopback_channels_get(struct snd_kcontrol *kcontrol, 926 struct snd_ctl_elem_value *ucontrol) 927 { 928 struct loopback *loopback = snd_kcontrol_chip(kcontrol); 929 930 ucontrol->value.integer.value[0] = 931 loopback->setup[kcontrol->id.subdevice] 932 [kcontrol->id.device].channels; 933 return 0; 934 } 935 936 static struct snd_kcontrol_new loopback_controls[] __devinitdata = { 937 { 938 .iface = SNDRV_CTL_ELEM_IFACE_PCM, 939 .name = "PCM Rate Shift 100000", 940 .info = loopback_rate_shift_info, 941 .get = loopback_rate_shift_get, 942 .put = loopback_rate_shift_put, 943 }, 944 { 945 .iface = SNDRV_CTL_ELEM_IFACE_PCM, 946 .name = "PCM Notify", 947 .info = snd_ctl_boolean_mono_info, 948 .get = loopback_notify_get, 949 .put = loopback_notify_put, 950 }, 951 #define ACTIVE_IDX 2 952 { 953 .access = SNDRV_CTL_ELEM_ACCESS_READ, 954 .iface = SNDRV_CTL_ELEM_IFACE_PCM, 955 .name = "PCM Slave Active", 956 .info = snd_ctl_boolean_mono_info, 957 .get = loopback_active_get, 958 }, 959 #define FORMAT_IDX 3 960 { 961 .access = SNDRV_CTL_ELEM_ACCESS_READ, 962 .iface = SNDRV_CTL_ELEM_IFACE_PCM, 963 .name = "PCM Slave Format", 964 .info = loopback_format_info, 965 .get = loopback_format_get 966 }, 967 #define RATE_IDX 4 968 { 969 .access = SNDRV_CTL_ELEM_ACCESS_READ, 970 .iface = SNDRV_CTL_ELEM_IFACE_PCM, 971 .name = "PCM Slave Rate", 972 .info = loopback_rate_info, 973 .get = loopback_rate_get 974 }, 975 #define CHANNELS_IDX 5 976 { 977 .access = SNDRV_CTL_ELEM_ACCESS_READ, 978 .iface = SNDRV_CTL_ELEM_IFACE_PCM, 979 .name = "PCM Slave Channels", 980 .info = loopback_channels_info, 981 .get = loopback_channels_get 982 } 983 }; 984 985 static int __devinit loopback_mixer_new(struct loopback *loopback, int notify) 986 { 987 struct snd_card *card = loopback->card; 988 struct snd_pcm *pcm; 989 struct snd_kcontrol *kctl; 990 struct loopback_setup *setup; 991 int err, dev, substr, substr_count, idx; 992 993 strcpy(card->mixername, "Loopback Mixer"); 994 for (dev = 0; dev < 2; dev++) { 995 pcm = loopback->pcm[dev]; 996 substr_count = 997 pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream_count; 998 for (substr = 0; substr < substr_count; substr++) { 999 setup = &loopback->setup[substr][dev]; 1000 setup->notify = notify; 1001 setup->rate_shift = NO_PITCH; 1002 setup->format = SNDRV_PCM_FORMAT_S16_LE; 1003 setup->rate = 48000; 1004 setup->channels = 2; 1005 for (idx = 0; idx < ARRAY_SIZE(loopback_controls); 1006 idx++) { 1007 kctl = snd_ctl_new1(&loopback_controls[idx], 1008 loopback); 1009 if (!kctl) 1010 return -ENOMEM; 1011 kctl->id.device = dev; 1012 kctl->id.subdevice = substr; 1013 switch (idx) { 1014 case ACTIVE_IDX: 1015 setup->active_id = kctl->id; 1016 break; 1017 case FORMAT_IDX: 1018 setup->format_id = kctl->id; 1019 break; 1020 case RATE_IDX: 1021 setup->rate_id = kctl->id; 1022 break; 1023 case CHANNELS_IDX: 1024 setup->channels_id = kctl->id; 1025 break; 1026 default: 1027 break; 1028 } 1029 err = snd_ctl_add(card, kctl); 1030 if (err < 0) 1031 return err; 1032 } 1033 } 1034 } 1035 return 0; 1036 } 1037 1038 #ifdef CONFIG_PROC_FS 1039 1040 static void print_dpcm_info(struct snd_info_buffer *buffer, 1041 struct loopback_pcm *dpcm, 1042 const char *id) 1043 { 1044 snd_iprintf(buffer, " %s\n", id); 1045 if (dpcm == NULL) { 1046 snd_iprintf(buffer, " inactive\n"); 1047 return; 1048 } 1049 snd_iprintf(buffer, " buffer_size:\t%u\n", dpcm->pcm_buffer_size); 1050 snd_iprintf(buffer, " buffer_pos:\t\t%u\n", dpcm->buf_pos); 1051 snd_iprintf(buffer, " silent_size:\t%u\n", dpcm->silent_size); 1052 snd_iprintf(buffer, " period_size:\t%u\n", dpcm->pcm_period_size); 1053 snd_iprintf(buffer, " bytes_per_sec:\t%u\n", dpcm->pcm_bps); 1054 snd_iprintf(buffer, " sample_align:\t%u\n", dpcm->pcm_salign); 1055 snd_iprintf(buffer, " rate_shift:\t\t%u\n", dpcm->pcm_rate_shift); 1056 snd_iprintf(buffer, " update_pending:\t%u\n", 1057 dpcm->period_update_pending); 1058 snd_iprintf(buffer, " irq_pos:\t\t%u\n", dpcm->irq_pos); 1059 snd_iprintf(buffer, " period_frac:\t%u\n", dpcm->period_size_frac); 1060 snd_iprintf(buffer, " last_jiffies:\t%lu (%lu)\n", 1061 dpcm->last_jiffies, jiffies); 1062 snd_iprintf(buffer, " timer_expires:\t%lu\n", dpcm->timer.expires); 1063 } 1064 1065 static void print_substream_info(struct snd_info_buffer *buffer, 1066 struct loopback *loopback, 1067 int sub, 1068 int num) 1069 { 1070 struct loopback_cable *cable = loopback->cables[sub][num]; 1071 1072 snd_iprintf(buffer, "Cable %i substream %i:\n", num, sub); 1073 if (cable == NULL) { 1074 snd_iprintf(buffer, " inactive\n"); 1075 return; 1076 } 1077 snd_iprintf(buffer, " valid: %u\n", cable->valid); 1078 snd_iprintf(buffer, " running: %u\n", cable->running); 1079 snd_iprintf(buffer, " pause: %u\n", cable->pause); 1080 print_dpcm_info(buffer, cable->streams[0], "Playback"); 1081 print_dpcm_info(buffer, cable->streams[1], "Capture"); 1082 } 1083 1084 static void print_cable_info(struct snd_info_entry *entry, 1085 struct snd_info_buffer *buffer) 1086 { 1087 struct loopback *loopback = entry->private_data; 1088 int sub, num; 1089 1090 mutex_lock(&loopback->cable_lock); 1091 num = entry->name[strlen(entry->name)-1]; 1092 num = num == '0' ? 0 : 1; 1093 for (sub = 0; sub < MAX_PCM_SUBSTREAMS; sub++) 1094 print_substream_info(buffer, loopback, sub, num); 1095 mutex_unlock(&loopback->cable_lock); 1096 } 1097 1098 static int __devinit loopback_proc_new(struct loopback *loopback, int cidx) 1099 { 1100 char name[32]; 1101 struct snd_info_entry *entry; 1102 int err; 1103 1104 snprintf(name, sizeof(name), "cable#%d", cidx); 1105 err = snd_card_proc_new(loopback->card, name, &entry); 1106 if (err < 0) 1107 return err; 1108 1109 snd_info_set_text_ops(entry, loopback, print_cable_info); 1110 return 0; 1111 } 1112 1113 #else /* !CONFIG_PROC_FS */ 1114 1115 #define loopback_proc_new(loopback, cidx) do { } while (0) 1116 1117 #endif 1118 1119 static int __devinit loopback_probe(struct platform_device *devptr) 1120 { 1121 struct snd_card *card; 1122 struct loopback *loopback; 1123 int dev = devptr->id; 1124 int err; 1125 1126 err = snd_card_create(index[dev], id[dev], THIS_MODULE, 1127 sizeof(struct loopback), &card); 1128 if (err < 0) 1129 return err; 1130 loopback = card->private_data; 1131 1132 if (pcm_substreams[dev] < 1) 1133 pcm_substreams[dev] = 1; 1134 if (pcm_substreams[dev] > MAX_PCM_SUBSTREAMS) 1135 pcm_substreams[dev] = MAX_PCM_SUBSTREAMS; 1136 1137 loopback->card = card; 1138 mutex_init(&loopback->cable_lock); 1139 1140 err = loopback_pcm_new(loopback, 0, pcm_substreams[dev]); 1141 if (err < 0) 1142 goto __nodev; 1143 err = loopback_pcm_new(loopback, 1, pcm_substreams[dev]); 1144 if (err < 0) 1145 goto __nodev; 1146 err = loopback_mixer_new(loopback, pcm_notify[dev] ? 1 : 0); 1147 if (err < 0) 1148 goto __nodev; 1149 loopback_proc_new(loopback, 0); 1150 loopback_proc_new(loopback, 1); 1151 strcpy(card->driver, "Loopback"); 1152 strcpy(card->shortname, "Loopback"); 1153 sprintf(card->longname, "Loopback %i", dev + 1); 1154 err = snd_card_register(card); 1155 if (!err) { 1156 platform_set_drvdata(devptr, card); 1157 return 0; 1158 } 1159 __nodev: 1160 snd_card_free(card); 1161 return err; 1162 } 1163 1164 static int __devexit loopback_remove(struct platform_device *devptr) 1165 { 1166 snd_card_free(platform_get_drvdata(devptr)); 1167 platform_set_drvdata(devptr, NULL); 1168 return 0; 1169 } 1170 1171 #ifdef CONFIG_PM 1172 static int loopback_suspend(struct platform_device *pdev, 1173 pm_message_t state) 1174 { 1175 struct snd_card *card = platform_get_drvdata(pdev); 1176 struct loopback *loopback = card->private_data; 1177 1178 snd_power_change_state(card, SNDRV_CTL_POWER_D3hot); 1179 1180 snd_pcm_suspend_all(loopback->pcm[0]); 1181 snd_pcm_suspend_all(loopback->pcm[1]); 1182 return 0; 1183 } 1184 1185 static int loopback_resume(struct platform_device *pdev) 1186 { 1187 struct snd_card *card = platform_get_drvdata(pdev); 1188 1189 snd_power_change_state(card, SNDRV_CTL_POWER_D0); 1190 return 0; 1191 } 1192 #endif 1193 1194 #define SND_LOOPBACK_DRIVER "snd_aloop" 1195 1196 static struct platform_driver loopback_driver = { 1197 .probe = loopback_probe, 1198 .remove = __devexit_p(loopback_remove), 1199 #ifdef CONFIG_PM 1200 .suspend = loopback_suspend, 1201 .resume = loopback_resume, 1202 #endif 1203 .driver = { 1204 .name = SND_LOOPBACK_DRIVER 1205 }, 1206 }; 1207 1208 static void loopback_unregister_all(void) 1209 { 1210 int i; 1211 1212 for (i = 0; i < ARRAY_SIZE(devices); ++i) 1213 platform_device_unregister(devices[i]); 1214 platform_driver_unregister(&loopback_driver); 1215 } 1216 1217 static int __init alsa_card_loopback_init(void) 1218 { 1219 int i, err, cards; 1220 1221 err = platform_driver_register(&loopback_driver); 1222 if (err < 0) 1223 return err; 1224 1225 1226 cards = 0; 1227 for (i = 0; i < SNDRV_CARDS; i++) { 1228 struct platform_device *device; 1229 if (!enable[i]) 1230 continue; 1231 device = platform_device_register_simple(SND_LOOPBACK_DRIVER, 1232 i, NULL, 0); 1233 if (IS_ERR(device)) 1234 continue; 1235 if (!platform_get_drvdata(device)) { 1236 platform_device_unregister(device); 1237 continue; 1238 } 1239 devices[i] = device; 1240 cards++; 1241 } 1242 if (!cards) { 1243 #ifdef MODULE 1244 printk(KERN_ERR "aloop: No loopback enabled\n"); 1245 #endif 1246 loopback_unregister_all(); 1247 return -ENODEV; 1248 } 1249 return 0; 1250 } 1251 1252 static void __exit alsa_card_loopback_exit(void) 1253 { 1254 loopback_unregister_all(); 1255 } 1256 1257 module_init(alsa_card_loopback_init) 1258 module_exit(alsa_card_loopback_exit) 1259