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 bool 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 int last_drift; 121 unsigned long last_jiffies; 122 struct timer_list timer; 123 }; 124 125 static struct platform_device *devices[SNDRV_CARDS]; 126 127 static inline unsigned int byte_pos(struct loopback_pcm *dpcm, unsigned int x) 128 { 129 if (dpcm->pcm_rate_shift == NO_PITCH) { 130 x /= HZ; 131 } else { 132 x = div_u64(NO_PITCH * (unsigned long long)x, 133 HZ * (unsigned long long)dpcm->pcm_rate_shift); 134 } 135 return x - (x % dpcm->pcm_salign); 136 } 137 138 static inline unsigned int frac_pos(struct loopback_pcm *dpcm, unsigned int x) 139 { 140 if (dpcm->pcm_rate_shift == NO_PITCH) { /* no pitch */ 141 return x * HZ; 142 } else { 143 x = div_u64(dpcm->pcm_rate_shift * (unsigned long long)x * HZ, 144 NO_PITCH); 145 } 146 return x; 147 } 148 149 static inline struct loopback_setup *get_setup(struct loopback_pcm *dpcm) 150 { 151 int device = dpcm->substream->pstr->pcm->device; 152 153 if (dpcm->substream->stream == SNDRV_PCM_STREAM_PLAYBACK) 154 device ^= 1; 155 return &dpcm->loopback->setup[dpcm->substream->number][device]; 156 } 157 158 static inline unsigned int get_notify(struct loopback_pcm *dpcm) 159 { 160 return get_setup(dpcm)->notify; 161 } 162 163 static inline unsigned int get_rate_shift(struct loopback_pcm *dpcm) 164 { 165 return get_setup(dpcm)->rate_shift; 166 } 167 168 static void loopback_timer_start(struct loopback_pcm *dpcm) 169 { 170 unsigned long tick; 171 unsigned int rate_shift = get_rate_shift(dpcm); 172 173 if (rate_shift != dpcm->pcm_rate_shift) { 174 dpcm->pcm_rate_shift = rate_shift; 175 dpcm->period_size_frac = frac_pos(dpcm, dpcm->pcm_period_size); 176 } 177 if (dpcm->period_size_frac <= dpcm->irq_pos) { 178 dpcm->irq_pos %= dpcm->period_size_frac; 179 dpcm->period_update_pending = 1; 180 } 181 tick = dpcm->period_size_frac - dpcm->irq_pos; 182 tick = (tick + dpcm->pcm_bps - 1) / dpcm->pcm_bps; 183 dpcm->timer.expires = jiffies + tick; 184 add_timer(&dpcm->timer); 185 } 186 187 static inline void loopback_timer_stop(struct loopback_pcm *dpcm) 188 { 189 del_timer(&dpcm->timer); 190 dpcm->timer.expires = 0; 191 } 192 193 #define CABLE_VALID_PLAYBACK (1 << SNDRV_PCM_STREAM_PLAYBACK) 194 #define CABLE_VALID_CAPTURE (1 << SNDRV_PCM_STREAM_CAPTURE) 195 #define CABLE_VALID_BOTH (CABLE_VALID_PLAYBACK|CABLE_VALID_CAPTURE) 196 197 static int loopback_check_format(struct loopback_cable *cable, int stream) 198 { 199 struct snd_pcm_runtime *runtime, *cruntime; 200 struct loopback_setup *setup; 201 struct snd_card *card; 202 int check; 203 204 if (cable->valid != CABLE_VALID_BOTH) { 205 if (stream == SNDRV_PCM_STREAM_PLAYBACK) 206 goto __notify; 207 return 0; 208 } 209 runtime = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]-> 210 substream->runtime; 211 cruntime = cable->streams[SNDRV_PCM_STREAM_CAPTURE]-> 212 substream->runtime; 213 check = runtime->format != cruntime->format || 214 runtime->rate != cruntime->rate || 215 runtime->channels != cruntime->channels; 216 if (!check) 217 return 0; 218 if (stream == SNDRV_PCM_STREAM_CAPTURE) { 219 return -EIO; 220 } else { 221 snd_pcm_stop(cable->streams[SNDRV_PCM_STREAM_CAPTURE]-> 222 substream, SNDRV_PCM_STATE_DRAINING); 223 __notify: 224 runtime = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]-> 225 substream->runtime; 226 setup = get_setup(cable->streams[SNDRV_PCM_STREAM_PLAYBACK]); 227 card = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]->loopback->card; 228 if (setup->format != runtime->format) { 229 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE, 230 &setup->format_id); 231 setup->format = runtime->format; 232 } 233 if (setup->rate != runtime->rate) { 234 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE, 235 &setup->rate_id); 236 setup->rate = runtime->rate; 237 } 238 if (setup->channels != runtime->channels) { 239 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE, 240 &setup->channels_id); 241 setup->channels = runtime->channels; 242 } 243 } 244 return 0; 245 } 246 247 static void loopback_active_notify(struct loopback_pcm *dpcm) 248 { 249 snd_ctl_notify(dpcm->loopback->card, 250 SNDRV_CTL_EVENT_MASK_VALUE, 251 &get_setup(dpcm)->active_id); 252 } 253 254 static int loopback_trigger(struct snd_pcm_substream *substream, int cmd) 255 { 256 struct snd_pcm_runtime *runtime = substream->runtime; 257 struct loopback_pcm *dpcm = runtime->private_data; 258 struct loopback_cable *cable = dpcm->cable; 259 int err, stream = 1 << substream->stream; 260 261 switch (cmd) { 262 case SNDRV_PCM_TRIGGER_START: 263 err = loopback_check_format(cable, substream->stream); 264 if (err < 0) 265 return err; 266 dpcm->last_jiffies = jiffies; 267 dpcm->pcm_rate_shift = 0; 268 dpcm->last_drift = 0; 269 spin_lock(&cable->lock); 270 cable->running |= stream; 271 cable->pause &= ~stream; 272 spin_unlock(&cable->lock); 273 loopback_timer_start(dpcm); 274 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) 275 loopback_active_notify(dpcm); 276 break; 277 case SNDRV_PCM_TRIGGER_STOP: 278 spin_lock(&cable->lock); 279 cable->running &= ~stream; 280 cable->pause &= ~stream; 281 spin_unlock(&cable->lock); 282 loopback_timer_stop(dpcm); 283 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) 284 loopback_active_notify(dpcm); 285 break; 286 case SNDRV_PCM_TRIGGER_PAUSE_PUSH: 287 spin_lock(&cable->lock); 288 cable->pause |= stream; 289 spin_unlock(&cable->lock); 290 loopback_timer_stop(dpcm); 291 break; 292 case SNDRV_PCM_TRIGGER_PAUSE_RELEASE: 293 spin_lock(&cable->lock); 294 dpcm->last_jiffies = jiffies; 295 cable->pause &= ~stream; 296 spin_unlock(&cable->lock); 297 loopback_timer_start(dpcm); 298 break; 299 default: 300 return -EINVAL; 301 } 302 return 0; 303 } 304 305 static void params_change_substream(struct loopback_pcm *dpcm, 306 struct snd_pcm_runtime *runtime) 307 { 308 struct snd_pcm_runtime *dst_runtime; 309 310 if (dpcm == NULL || dpcm->substream == NULL) 311 return; 312 dst_runtime = dpcm->substream->runtime; 313 if (dst_runtime == NULL) 314 return; 315 dst_runtime->hw = dpcm->cable->hw; 316 } 317 318 static void params_change(struct snd_pcm_substream *substream) 319 { 320 struct snd_pcm_runtime *runtime = substream->runtime; 321 struct loopback_pcm *dpcm = runtime->private_data; 322 struct loopback_cable *cable = dpcm->cable; 323 324 cable->hw.formats = (1ULL << runtime->format); 325 cable->hw.rate_min = runtime->rate; 326 cable->hw.rate_max = runtime->rate; 327 cable->hw.channels_min = runtime->channels; 328 cable->hw.channels_max = runtime->channels; 329 params_change_substream(cable->streams[SNDRV_PCM_STREAM_PLAYBACK], 330 runtime); 331 params_change_substream(cable->streams[SNDRV_PCM_STREAM_CAPTURE], 332 runtime); 333 } 334 335 static int loopback_prepare(struct snd_pcm_substream *substream) 336 { 337 struct snd_pcm_runtime *runtime = substream->runtime; 338 struct loopback_pcm *dpcm = runtime->private_data; 339 struct loopback_cable *cable = dpcm->cable; 340 int bps, salign; 341 342 salign = (snd_pcm_format_width(runtime->format) * 343 runtime->channels) / 8; 344 bps = salign * runtime->rate; 345 if (bps <= 0 || salign <= 0) 346 return -EINVAL; 347 348 dpcm->buf_pos = 0; 349 dpcm->pcm_buffer_size = frames_to_bytes(runtime, runtime->buffer_size); 350 if (substream->stream == SNDRV_PCM_STREAM_CAPTURE) { 351 /* clear capture buffer */ 352 dpcm->silent_size = dpcm->pcm_buffer_size; 353 snd_pcm_format_set_silence(runtime->format, runtime->dma_area, 354 runtime->buffer_size * runtime->channels); 355 } 356 357 dpcm->irq_pos = 0; 358 dpcm->period_update_pending = 0; 359 dpcm->pcm_bps = bps; 360 dpcm->pcm_salign = salign; 361 dpcm->pcm_period_size = frames_to_bytes(runtime, runtime->period_size); 362 363 mutex_lock(&dpcm->loopback->cable_lock); 364 if (!(cable->valid & ~(1 << substream->stream)) || 365 (get_setup(dpcm)->notify && 366 substream->stream == SNDRV_PCM_STREAM_PLAYBACK)) 367 params_change(substream); 368 cable->valid |= 1 << substream->stream; 369 mutex_unlock(&dpcm->loopback->cable_lock); 370 371 return 0; 372 } 373 374 static void clear_capture_buf(struct loopback_pcm *dpcm, unsigned int bytes) 375 { 376 struct snd_pcm_runtime *runtime = dpcm->substream->runtime; 377 char *dst = runtime->dma_area; 378 unsigned int dst_off = dpcm->buf_pos; 379 380 if (dpcm->silent_size >= dpcm->pcm_buffer_size) 381 return; 382 if (dpcm->silent_size + bytes > dpcm->pcm_buffer_size) 383 bytes = dpcm->pcm_buffer_size - dpcm->silent_size; 384 385 for (;;) { 386 unsigned int size = bytes; 387 if (dst_off + size > dpcm->pcm_buffer_size) 388 size = dpcm->pcm_buffer_size - dst_off; 389 snd_pcm_format_set_silence(runtime->format, dst + dst_off, 390 bytes_to_frames(runtime, size) * 391 runtime->channels); 392 dpcm->silent_size += size; 393 bytes -= size; 394 if (!bytes) 395 break; 396 dst_off = 0; 397 } 398 } 399 400 static void copy_play_buf(struct loopback_pcm *play, 401 struct loopback_pcm *capt, 402 unsigned int bytes) 403 { 404 struct snd_pcm_runtime *runtime = play->substream->runtime; 405 char *src = runtime->dma_area; 406 char *dst = capt->substream->runtime->dma_area; 407 unsigned int src_off = play->buf_pos; 408 unsigned int dst_off = capt->buf_pos; 409 unsigned int clear_bytes = 0; 410 411 /* check if playback is draining, trim the capture copy size 412 * when our pointer is at the end of playback ring buffer */ 413 if (runtime->status->state == SNDRV_PCM_STATE_DRAINING && 414 snd_pcm_playback_hw_avail(runtime) < runtime->buffer_size) { 415 snd_pcm_uframes_t appl_ptr, appl_ptr1, diff; 416 appl_ptr = appl_ptr1 = runtime->control->appl_ptr; 417 appl_ptr1 -= appl_ptr1 % runtime->buffer_size; 418 appl_ptr1 += play->buf_pos / play->pcm_salign; 419 if (appl_ptr < appl_ptr1) 420 appl_ptr1 -= runtime->buffer_size; 421 diff = (appl_ptr - appl_ptr1) * play->pcm_salign; 422 if (diff < bytes) { 423 clear_bytes = bytes - diff; 424 bytes = diff; 425 } 426 } 427 428 for (;;) { 429 unsigned int size = bytes; 430 if (src_off + size > play->pcm_buffer_size) 431 size = play->pcm_buffer_size - src_off; 432 if (dst_off + size > capt->pcm_buffer_size) 433 size = capt->pcm_buffer_size - dst_off; 434 memcpy(dst + dst_off, src + src_off, size); 435 capt->silent_size = 0; 436 bytes -= size; 437 if (!bytes) 438 break; 439 src_off = (src_off + size) % play->pcm_buffer_size; 440 dst_off = (dst_off + size) % capt->pcm_buffer_size; 441 } 442 443 if (clear_bytes > 0) { 444 clear_capture_buf(capt, clear_bytes); 445 capt->silent_size = 0; 446 } 447 } 448 449 static inline unsigned int bytepos_delta(struct loopback_pcm *dpcm, 450 unsigned int jiffies_delta) 451 { 452 unsigned long last_pos; 453 unsigned int delta; 454 455 last_pos = byte_pos(dpcm, dpcm->irq_pos); 456 dpcm->irq_pos += jiffies_delta * dpcm->pcm_bps; 457 delta = byte_pos(dpcm, dpcm->irq_pos) - last_pos; 458 if (delta >= dpcm->last_drift) 459 delta -= dpcm->last_drift; 460 dpcm->last_drift = 0; 461 if (dpcm->irq_pos >= dpcm->period_size_frac) { 462 dpcm->irq_pos %= dpcm->period_size_frac; 463 dpcm->period_update_pending = 1; 464 } 465 return delta; 466 } 467 468 static inline void bytepos_finish(struct loopback_pcm *dpcm, 469 unsigned int delta) 470 { 471 dpcm->buf_pos += delta; 472 dpcm->buf_pos %= dpcm->pcm_buffer_size; 473 } 474 475 static unsigned int loopback_pos_update(struct loopback_cable *cable) 476 { 477 struct loopback_pcm *dpcm_play = 478 cable->streams[SNDRV_PCM_STREAM_PLAYBACK]; 479 struct loopback_pcm *dpcm_capt = 480 cable->streams[SNDRV_PCM_STREAM_CAPTURE]; 481 unsigned long delta_play = 0, delta_capt = 0; 482 unsigned int running, count1, count2; 483 unsigned long flags; 484 485 spin_lock_irqsave(&cable->lock, flags); 486 running = cable->running ^ cable->pause; 487 if (running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) { 488 delta_play = jiffies - dpcm_play->last_jiffies; 489 dpcm_play->last_jiffies += delta_play; 490 } 491 492 if (running & (1 << SNDRV_PCM_STREAM_CAPTURE)) { 493 delta_capt = jiffies - dpcm_capt->last_jiffies; 494 dpcm_capt->last_jiffies += delta_capt; 495 } 496 497 if (delta_play == 0 && delta_capt == 0) 498 goto unlock; 499 500 if (delta_play > delta_capt) { 501 count1 = bytepos_delta(dpcm_play, delta_play - delta_capt); 502 bytepos_finish(dpcm_play, count1); 503 delta_play = delta_capt; 504 } else if (delta_play < delta_capt) { 505 count1 = bytepos_delta(dpcm_capt, delta_capt - delta_play); 506 clear_capture_buf(dpcm_capt, count1); 507 bytepos_finish(dpcm_capt, count1); 508 delta_capt = delta_play; 509 } 510 511 if (delta_play == 0 && delta_capt == 0) 512 goto unlock; 513 514 /* note delta_capt == delta_play at this moment */ 515 count1 = bytepos_delta(dpcm_play, delta_play); 516 count2 = bytepos_delta(dpcm_capt, delta_capt); 517 if (count1 < count2) { 518 dpcm_capt->last_drift = count2 - count1; 519 count1 = count2; 520 } else if (count1 > count2) { 521 dpcm_play->last_drift = count1 - count2; 522 } 523 copy_play_buf(dpcm_play, dpcm_capt, count1); 524 bytepos_finish(dpcm_play, count1); 525 bytepos_finish(dpcm_capt, count1); 526 unlock: 527 spin_unlock_irqrestore(&cable->lock, flags); 528 return running; 529 } 530 531 static void loopback_timer_function(unsigned long data) 532 { 533 struct loopback_pcm *dpcm = (struct loopback_pcm *)data; 534 unsigned int running; 535 536 running = loopback_pos_update(dpcm->cable); 537 if (running & (1 << dpcm->substream->stream)) { 538 loopback_timer_start(dpcm); 539 if (dpcm->period_update_pending) { 540 dpcm->period_update_pending = 0; 541 snd_pcm_period_elapsed(dpcm->substream); 542 } 543 } 544 } 545 546 static snd_pcm_uframes_t loopback_pointer(struct snd_pcm_substream *substream) 547 { 548 struct snd_pcm_runtime *runtime = substream->runtime; 549 struct loopback_pcm *dpcm = runtime->private_data; 550 551 loopback_pos_update(dpcm->cable); 552 return bytes_to_frames(runtime, dpcm->buf_pos); 553 } 554 555 static struct snd_pcm_hardware loopback_pcm_hardware = 556 { 557 .info = (SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_MMAP | 558 SNDRV_PCM_INFO_MMAP_VALID | SNDRV_PCM_INFO_PAUSE), 559 .formats = (SNDRV_PCM_FMTBIT_S16_LE | SNDRV_PCM_FMTBIT_S16_BE | 560 SNDRV_PCM_FMTBIT_S32_LE | SNDRV_PCM_FMTBIT_S32_BE | 561 SNDRV_PCM_FMTBIT_FLOAT_LE | SNDRV_PCM_FMTBIT_FLOAT_BE), 562 .rates = SNDRV_PCM_RATE_CONTINUOUS | SNDRV_PCM_RATE_8000_192000, 563 .rate_min = 8000, 564 .rate_max = 192000, 565 .channels_min = 1, 566 .channels_max = 32, 567 .buffer_bytes_max = 2 * 1024 * 1024, 568 .period_bytes_min = 64, 569 /* note check overflow in frac_pos() using pcm_rate_shift before 570 changing period_bytes_max value */ 571 .period_bytes_max = 1024 * 1024, 572 .periods_min = 1, 573 .periods_max = 1024, 574 .fifo_size = 0, 575 }; 576 577 static void loopback_runtime_free(struct snd_pcm_runtime *runtime) 578 { 579 struct loopback_pcm *dpcm = runtime->private_data; 580 kfree(dpcm); 581 } 582 583 static int loopback_hw_params(struct snd_pcm_substream *substream, 584 struct snd_pcm_hw_params *params) 585 { 586 return snd_pcm_lib_alloc_vmalloc_buffer(substream, 587 params_buffer_bytes(params)); 588 } 589 590 static int loopback_hw_free(struct snd_pcm_substream *substream) 591 { 592 struct snd_pcm_runtime *runtime = substream->runtime; 593 struct loopback_pcm *dpcm = runtime->private_data; 594 struct loopback_cable *cable = dpcm->cable; 595 596 mutex_lock(&dpcm->loopback->cable_lock); 597 cable->valid &= ~(1 << substream->stream); 598 mutex_unlock(&dpcm->loopback->cable_lock); 599 return snd_pcm_lib_free_vmalloc_buffer(substream); 600 } 601 602 static unsigned int get_cable_index(struct snd_pcm_substream *substream) 603 { 604 if (!substream->pcm->device) 605 return substream->stream; 606 else 607 return !substream->stream; 608 } 609 610 static int rule_format(struct snd_pcm_hw_params *params, 611 struct snd_pcm_hw_rule *rule) 612 { 613 614 struct snd_pcm_hardware *hw = rule->private; 615 struct snd_mask *maskp = hw_param_mask(params, rule->var); 616 617 maskp->bits[0] &= (u_int32_t)hw->formats; 618 maskp->bits[1] &= (u_int32_t)(hw->formats >> 32); 619 memset(maskp->bits + 2, 0, (SNDRV_MASK_MAX-64) / 8); /* clear rest */ 620 if (! maskp->bits[0] && ! maskp->bits[1]) 621 return -EINVAL; 622 return 0; 623 } 624 625 static int rule_rate(struct snd_pcm_hw_params *params, 626 struct snd_pcm_hw_rule *rule) 627 { 628 struct snd_pcm_hardware *hw = rule->private; 629 struct snd_interval t; 630 631 t.min = hw->rate_min; 632 t.max = hw->rate_max; 633 t.openmin = t.openmax = 0; 634 t.integer = 0; 635 return snd_interval_refine(hw_param_interval(params, rule->var), &t); 636 } 637 638 static int rule_channels(struct snd_pcm_hw_params *params, 639 struct snd_pcm_hw_rule *rule) 640 { 641 struct snd_pcm_hardware *hw = rule->private; 642 struct snd_interval t; 643 644 t.min = hw->channels_min; 645 t.max = hw->channels_max; 646 t.openmin = t.openmax = 0; 647 t.integer = 0; 648 return snd_interval_refine(hw_param_interval(params, rule->var), &t); 649 } 650 651 static int loopback_open(struct snd_pcm_substream *substream) 652 { 653 struct snd_pcm_runtime *runtime = substream->runtime; 654 struct loopback *loopback = substream->private_data; 655 struct loopback_pcm *dpcm; 656 struct loopback_cable *cable; 657 int err = 0; 658 int dev = get_cable_index(substream); 659 660 mutex_lock(&loopback->cable_lock); 661 dpcm = kzalloc(sizeof(*dpcm), GFP_KERNEL); 662 if (!dpcm) { 663 err = -ENOMEM; 664 goto unlock; 665 } 666 dpcm->loopback = loopback; 667 dpcm->substream = substream; 668 setup_timer(&dpcm->timer, loopback_timer_function, 669 (unsigned long)dpcm); 670 671 cable = loopback->cables[substream->number][dev]; 672 if (!cable) { 673 cable = kzalloc(sizeof(*cable), GFP_KERNEL); 674 if (!cable) { 675 kfree(dpcm); 676 err = -ENOMEM; 677 goto unlock; 678 } 679 spin_lock_init(&cable->lock); 680 cable->hw = loopback_pcm_hardware; 681 loopback->cables[substream->number][dev] = cable; 682 } 683 dpcm->cable = cable; 684 cable->streams[substream->stream] = dpcm; 685 686 snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS); 687 688 /* use dynamic rules based on actual runtime->hw values */ 689 /* note that the default rules created in the PCM midlevel code */ 690 /* are cached -> they do not reflect the actual state */ 691 err = snd_pcm_hw_rule_add(runtime, 0, 692 SNDRV_PCM_HW_PARAM_FORMAT, 693 rule_format, &runtime->hw, 694 SNDRV_PCM_HW_PARAM_FORMAT, -1); 695 if (err < 0) 696 goto unlock; 697 err = snd_pcm_hw_rule_add(runtime, 0, 698 SNDRV_PCM_HW_PARAM_RATE, 699 rule_rate, &runtime->hw, 700 SNDRV_PCM_HW_PARAM_RATE, -1); 701 if (err < 0) 702 goto unlock; 703 err = snd_pcm_hw_rule_add(runtime, 0, 704 SNDRV_PCM_HW_PARAM_CHANNELS, 705 rule_channels, &runtime->hw, 706 SNDRV_PCM_HW_PARAM_CHANNELS, -1); 707 if (err < 0) 708 goto unlock; 709 710 runtime->private_data = dpcm; 711 runtime->private_free = loopback_runtime_free; 712 if (get_notify(dpcm)) 713 runtime->hw = loopback_pcm_hardware; 714 else 715 runtime->hw = cable->hw; 716 unlock: 717 mutex_unlock(&loopback->cable_lock); 718 return err; 719 } 720 721 static int loopback_close(struct snd_pcm_substream *substream) 722 { 723 struct loopback *loopback = substream->private_data; 724 struct loopback_pcm *dpcm = substream->runtime->private_data; 725 struct loopback_cable *cable; 726 int dev = get_cable_index(substream); 727 728 loopback_timer_stop(dpcm); 729 mutex_lock(&loopback->cable_lock); 730 cable = loopback->cables[substream->number][dev]; 731 if (cable->streams[!substream->stream]) { 732 /* other stream is still alive */ 733 cable->streams[substream->stream] = NULL; 734 } else { 735 /* free the cable */ 736 loopback->cables[substream->number][dev] = NULL; 737 kfree(cable); 738 } 739 mutex_unlock(&loopback->cable_lock); 740 return 0; 741 } 742 743 static struct snd_pcm_ops loopback_playback_ops = { 744 .open = loopback_open, 745 .close = loopback_close, 746 .ioctl = snd_pcm_lib_ioctl, 747 .hw_params = loopback_hw_params, 748 .hw_free = loopback_hw_free, 749 .prepare = loopback_prepare, 750 .trigger = loopback_trigger, 751 .pointer = loopback_pointer, 752 .page = snd_pcm_lib_get_vmalloc_page, 753 .mmap = snd_pcm_lib_mmap_vmalloc, 754 }; 755 756 static struct snd_pcm_ops loopback_capture_ops = { 757 .open = loopback_open, 758 .close = loopback_close, 759 .ioctl = snd_pcm_lib_ioctl, 760 .hw_params = loopback_hw_params, 761 .hw_free = loopback_hw_free, 762 .prepare = loopback_prepare, 763 .trigger = loopback_trigger, 764 .pointer = loopback_pointer, 765 .page = snd_pcm_lib_get_vmalloc_page, 766 .mmap = snd_pcm_lib_mmap_vmalloc, 767 }; 768 769 static int __devinit loopback_pcm_new(struct loopback *loopback, 770 int device, int substreams) 771 { 772 struct snd_pcm *pcm; 773 int err; 774 775 err = snd_pcm_new(loopback->card, "Loopback PCM", device, 776 substreams, substreams, &pcm); 777 if (err < 0) 778 return err; 779 snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &loopback_playback_ops); 780 snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &loopback_capture_ops); 781 782 pcm->private_data = loopback; 783 pcm->info_flags = 0; 784 strcpy(pcm->name, "Loopback PCM"); 785 786 loopback->pcm[device] = pcm; 787 return 0; 788 } 789 790 static int loopback_rate_shift_info(struct snd_kcontrol *kcontrol, 791 struct snd_ctl_elem_info *uinfo) 792 { 793 uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER; 794 uinfo->count = 1; 795 uinfo->value.integer.min = 80000; 796 uinfo->value.integer.max = 120000; 797 uinfo->value.integer.step = 1; 798 return 0; 799 } 800 801 static int loopback_rate_shift_get(struct snd_kcontrol *kcontrol, 802 struct snd_ctl_elem_value *ucontrol) 803 { 804 struct loopback *loopback = snd_kcontrol_chip(kcontrol); 805 806 ucontrol->value.integer.value[0] = 807 loopback->setup[kcontrol->id.subdevice] 808 [kcontrol->id.device].rate_shift; 809 return 0; 810 } 811 812 static int loopback_rate_shift_put(struct snd_kcontrol *kcontrol, 813 struct snd_ctl_elem_value *ucontrol) 814 { 815 struct loopback *loopback = snd_kcontrol_chip(kcontrol); 816 unsigned int val; 817 int change = 0; 818 819 val = ucontrol->value.integer.value[0]; 820 if (val < 80000) 821 val = 80000; 822 if (val > 120000) 823 val = 120000; 824 mutex_lock(&loopback->cable_lock); 825 if (val != loopback->setup[kcontrol->id.subdevice] 826 [kcontrol->id.device].rate_shift) { 827 loopback->setup[kcontrol->id.subdevice] 828 [kcontrol->id.device].rate_shift = val; 829 change = 1; 830 } 831 mutex_unlock(&loopback->cable_lock); 832 return change; 833 } 834 835 static int loopback_notify_get(struct snd_kcontrol *kcontrol, 836 struct snd_ctl_elem_value *ucontrol) 837 { 838 struct loopback *loopback = snd_kcontrol_chip(kcontrol); 839 840 ucontrol->value.integer.value[0] = 841 loopback->setup[kcontrol->id.subdevice] 842 [kcontrol->id.device].notify; 843 return 0; 844 } 845 846 static int loopback_notify_put(struct snd_kcontrol *kcontrol, 847 struct snd_ctl_elem_value *ucontrol) 848 { 849 struct loopback *loopback = snd_kcontrol_chip(kcontrol); 850 unsigned int val; 851 int change = 0; 852 853 val = ucontrol->value.integer.value[0] ? 1 : 0; 854 if (val != loopback->setup[kcontrol->id.subdevice] 855 [kcontrol->id.device].notify) { 856 loopback->setup[kcontrol->id.subdevice] 857 [kcontrol->id.device].notify = val; 858 change = 1; 859 } 860 return change; 861 } 862 863 static int loopback_active_get(struct snd_kcontrol *kcontrol, 864 struct snd_ctl_elem_value *ucontrol) 865 { 866 struct loopback *loopback = snd_kcontrol_chip(kcontrol); 867 struct loopback_cable *cable = loopback->cables 868 [kcontrol->id.subdevice][kcontrol->id.device ^ 1]; 869 unsigned int val = 0; 870 871 if (cable != NULL) 872 val = (cable->running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) ? 873 1 : 0; 874 ucontrol->value.integer.value[0] = val; 875 return 0; 876 } 877 878 static int loopback_format_info(struct snd_kcontrol *kcontrol, 879 struct snd_ctl_elem_info *uinfo) 880 { 881 uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER; 882 uinfo->count = 1; 883 uinfo->value.integer.min = 0; 884 uinfo->value.integer.max = SNDRV_PCM_FORMAT_LAST; 885 uinfo->value.integer.step = 1; 886 return 0; 887 } 888 889 static int loopback_format_get(struct snd_kcontrol *kcontrol, 890 struct snd_ctl_elem_value *ucontrol) 891 { 892 struct loopback *loopback = snd_kcontrol_chip(kcontrol); 893 894 ucontrol->value.integer.value[0] = 895 loopback->setup[kcontrol->id.subdevice] 896 [kcontrol->id.device].format; 897 return 0; 898 } 899 900 static int loopback_rate_info(struct snd_kcontrol *kcontrol, 901 struct snd_ctl_elem_info *uinfo) 902 { 903 uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER; 904 uinfo->count = 1; 905 uinfo->value.integer.min = 0; 906 uinfo->value.integer.max = 192000; 907 uinfo->value.integer.step = 1; 908 return 0; 909 } 910 911 static int loopback_rate_get(struct snd_kcontrol *kcontrol, 912 struct snd_ctl_elem_value *ucontrol) 913 { 914 struct loopback *loopback = snd_kcontrol_chip(kcontrol); 915 916 ucontrol->value.integer.value[0] = 917 loopback->setup[kcontrol->id.subdevice] 918 [kcontrol->id.device].rate; 919 return 0; 920 } 921 922 static int loopback_channels_info(struct snd_kcontrol *kcontrol, 923 struct snd_ctl_elem_info *uinfo) 924 { 925 uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER; 926 uinfo->count = 1; 927 uinfo->value.integer.min = 1; 928 uinfo->value.integer.max = 1024; 929 uinfo->value.integer.step = 1; 930 return 0; 931 } 932 933 static int loopback_channels_get(struct snd_kcontrol *kcontrol, 934 struct snd_ctl_elem_value *ucontrol) 935 { 936 struct loopback *loopback = snd_kcontrol_chip(kcontrol); 937 938 ucontrol->value.integer.value[0] = 939 loopback->setup[kcontrol->id.subdevice] 940 [kcontrol->id.device].channels; 941 return 0; 942 } 943 944 static struct snd_kcontrol_new loopback_controls[] __devinitdata = { 945 { 946 .iface = SNDRV_CTL_ELEM_IFACE_PCM, 947 .name = "PCM Rate Shift 100000", 948 .info = loopback_rate_shift_info, 949 .get = loopback_rate_shift_get, 950 .put = loopback_rate_shift_put, 951 }, 952 { 953 .iface = SNDRV_CTL_ELEM_IFACE_PCM, 954 .name = "PCM Notify", 955 .info = snd_ctl_boolean_mono_info, 956 .get = loopback_notify_get, 957 .put = loopback_notify_put, 958 }, 959 #define ACTIVE_IDX 2 960 { 961 .access = SNDRV_CTL_ELEM_ACCESS_READ, 962 .iface = SNDRV_CTL_ELEM_IFACE_PCM, 963 .name = "PCM Slave Active", 964 .info = snd_ctl_boolean_mono_info, 965 .get = loopback_active_get, 966 }, 967 #define FORMAT_IDX 3 968 { 969 .access = SNDRV_CTL_ELEM_ACCESS_READ, 970 .iface = SNDRV_CTL_ELEM_IFACE_PCM, 971 .name = "PCM Slave Format", 972 .info = loopback_format_info, 973 .get = loopback_format_get 974 }, 975 #define RATE_IDX 4 976 { 977 .access = SNDRV_CTL_ELEM_ACCESS_READ, 978 .iface = SNDRV_CTL_ELEM_IFACE_PCM, 979 .name = "PCM Slave Rate", 980 .info = loopback_rate_info, 981 .get = loopback_rate_get 982 }, 983 #define CHANNELS_IDX 5 984 { 985 .access = SNDRV_CTL_ELEM_ACCESS_READ, 986 .iface = SNDRV_CTL_ELEM_IFACE_PCM, 987 .name = "PCM Slave Channels", 988 .info = loopback_channels_info, 989 .get = loopback_channels_get 990 } 991 }; 992 993 static int __devinit loopback_mixer_new(struct loopback *loopback, int notify) 994 { 995 struct snd_card *card = loopback->card; 996 struct snd_pcm *pcm; 997 struct snd_kcontrol *kctl; 998 struct loopback_setup *setup; 999 int err, dev, substr, substr_count, idx; 1000 1001 strcpy(card->mixername, "Loopback Mixer"); 1002 for (dev = 0; dev < 2; dev++) { 1003 pcm = loopback->pcm[dev]; 1004 substr_count = 1005 pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream_count; 1006 for (substr = 0; substr < substr_count; substr++) { 1007 setup = &loopback->setup[substr][dev]; 1008 setup->notify = notify; 1009 setup->rate_shift = NO_PITCH; 1010 setup->format = SNDRV_PCM_FORMAT_S16_LE; 1011 setup->rate = 48000; 1012 setup->channels = 2; 1013 for (idx = 0; idx < ARRAY_SIZE(loopback_controls); 1014 idx++) { 1015 kctl = snd_ctl_new1(&loopback_controls[idx], 1016 loopback); 1017 if (!kctl) 1018 return -ENOMEM; 1019 kctl->id.device = dev; 1020 kctl->id.subdevice = substr; 1021 switch (idx) { 1022 case ACTIVE_IDX: 1023 setup->active_id = kctl->id; 1024 break; 1025 case FORMAT_IDX: 1026 setup->format_id = kctl->id; 1027 break; 1028 case RATE_IDX: 1029 setup->rate_id = kctl->id; 1030 break; 1031 case CHANNELS_IDX: 1032 setup->channels_id = kctl->id; 1033 break; 1034 default: 1035 break; 1036 } 1037 err = snd_ctl_add(card, kctl); 1038 if (err < 0) 1039 return err; 1040 } 1041 } 1042 } 1043 return 0; 1044 } 1045 1046 #ifdef CONFIG_PROC_FS 1047 1048 static void print_dpcm_info(struct snd_info_buffer *buffer, 1049 struct loopback_pcm *dpcm, 1050 const char *id) 1051 { 1052 snd_iprintf(buffer, " %s\n", id); 1053 if (dpcm == NULL) { 1054 snd_iprintf(buffer, " inactive\n"); 1055 return; 1056 } 1057 snd_iprintf(buffer, " buffer_size:\t%u\n", dpcm->pcm_buffer_size); 1058 snd_iprintf(buffer, " buffer_pos:\t\t%u\n", dpcm->buf_pos); 1059 snd_iprintf(buffer, " silent_size:\t%u\n", dpcm->silent_size); 1060 snd_iprintf(buffer, " period_size:\t%u\n", dpcm->pcm_period_size); 1061 snd_iprintf(buffer, " bytes_per_sec:\t%u\n", dpcm->pcm_bps); 1062 snd_iprintf(buffer, " sample_align:\t%u\n", dpcm->pcm_salign); 1063 snd_iprintf(buffer, " rate_shift:\t\t%u\n", dpcm->pcm_rate_shift); 1064 snd_iprintf(buffer, " update_pending:\t%u\n", 1065 dpcm->period_update_pending); 1066 snd_iprintf(buffer, " irq_pos:\t\t%u\n", dpcm->irq_pos); 1067 snd_iprintf(buffer, " period_frac:\t%u\n", dpcm->period_size_frac); 1068 snd_iprintf(buffer, " last_jiffies:\t%lu (%lu)\n", 1069 dpcm->last_jiffies, jiffies); 1070 snd_iprintf(buffer, " timer_expires:\t%lu\n", dpcm->timer.expires); 1071 } 1072 1073 static void print_substream_info(struct snd_info_buffer *buffer, 1074 struct loopback *loopback, 1075 int sub, 1076 int num) 1077 { 1078 struct loopback_cable *cable = loopback->cables[sub][num]; 1079 1080 snd_iprintf(buffer, "Cable %i substream %i:\n", num, sub); 1081 if (cable == NULL) { 1082 snd_iprintf(buffer, " inactive\n"); 1083 return; 1084 } 1085 snd_iprintf(buffer, " valid: %u\n", cable->valid); 1086 snd_iprintf(buffer, " running: %u\n", cable->running); 1087 snd_iprintf(buffer, " pause: %u\n", cable->pause); 1088 print_dpcm_info(buffer, cable->streams[0], "Playback"); 1089 print_dpcm_info(buffer, cable->streams[1], "Capture"); 1090 } 1091 1092 static void print_cable_info(struct snd_info_entry *entry, 1093 struct snd_info_buffer *buffer) 1094 { 1095 struct loopback *loopback = entry->private_data; 1096 int sub, num; 1097 1098 mutex_lock(&loopback->cable_lock); 1099 num = entry->name[strlen(entry->name)-1]; 1100 num = num == '0' ? 0 : 1; 1101 for (sub = 0; sub < MAX_PCM_SUBSTREAMS; sub++) 1102 print_substream_info(buffer, loopback, sub, num); 1103 mutex_unlock(&loopback->cable_lock); 1104 } 1105 1106 static int __devinit loopback_proc_new(struct loopback *loopback, int cidx) 1107 { 1108 char name[32]; 1109 struct snd_info_entry *entry; 1110 int err; 1111 1112 snprintf(name, sizeof(name), "cable#%d", cidx); 1113 err = snd_card_proc_new(loopback->card, name, &entry); 1114 if (err < 0) 1115 return err; 1116 1117 snd_info_set_text_ops(entry, loopback, print_cable_info); 1118 return 0; 1119 } 1120 1121 #else /* !CONFIG_PROC_FS */ 1122 1123 #define loopback_proc_new(loopback, cidx) do { } while (0) 1124 1125 #endif 1126 1127 static int __devinit loopback_probe(struct platform_device *devptr) 1128 { 1129 struct snd_card *card; 1130 struct loopback *loopback; 1131 int dev = devptr->id; 1132 int err; 1133 1134 err = snd_card_create(index[dev], id[dev], THIS_MODULE, 1135 sizeof(struct loopback), &card); 1136 if (err < 0) 1137 return err; 1138 loopback = card->private_data; 1139 1140 if (pcm_substreams[dev] < 1) 1141 pcm_substreams[dev] = 1; 1142 if (pcm_substreams[dev] > MAX_PCM_SUBSTREAMS) 1143 pcm_substreams[dev] = MAX_PCM_SUBSTREAMS; 1144 1145 loopback->card = card; 1146 mutex_init(&loopback->cable_lock); 1147 1148 err = loopback_pcm_new(loopback, 0, pcm_substreams[dev]); 1149 if (err < 0) 1150 goto __nodev; 1151 err = loopback_pcm_new(loopback, 1, pcm_substreams[dev]); 1152 if (err < 0) 1153 goto __nodev; 1154 err = loopback_mixer_new(loopback, pcm_notify[dev] ? 1 : 0); 1155 if (err < 0) 1156 goto __nodev; 1157 loopback_proc_new(loopback, 0); 1158 loopback_proc_new(loopback, 1); 1159 strcpy(card->driver, "Loopback"); 1160 strcpy(card->shortname, "Loopback"); 1161 sprintf(card->longname, "Loopback %i", dev + 1); 1162 err = snd_card_register(card); 1163 if (!err) { 1164 platform_set_drvdata(devptr, card); 1165 return 0; 1166 } 1167 __nodev: 1168 snd_card_free(card); 1169 return err; 1170 } 1171 1172 static int __devexit loopback_remove(struct platform_device *devptr) 1173 { 1174 snd_card_free(platform_get_drvdata(devptr)); 1175 platform_set_drvdata(devptr, NULL); 1176 return 0; 1177 } 1178 1179 #ifdef CONFIG_PM 1180 static int loopback_suspend(struct device *pdev) 1181 { 1182 struct snd_card *card = dev_get_drvdata(pdev); 1183 struct loopback *loopback = card->private_data; 1184 1185 snd_power_change_state(card, SNDRV_CTL_POWER_D3hot); 1186 1187 snd_pcm_suspend_all(loopback->pcm[0]); 1188 snd_pcm_suspend_all(loopback->pcm[1]); 1189 return 0; 1190 } 1191 1192 static int loopback_resume(struct device *pdev) 1193 { 1194 struct snd_card *card = dev_get_drvdata(pdev); 1195 1196 snd_power_change_state(card, SNDRV_CTL_POWER_D0); 1197 return 0; 1198 } 1199 1200 static SIMPLE_DEV_PM_OPS(loopback_pm, loopback_suspend, loopback_resume); 1201 #define LOOPBACK_PM_OPS &loopback_pm 1202 #else 1203 #define LOOPBACK_PM_OPS NULL 1204 #endif 1205 1206 #define SND_LOOPBACK_DRIVER "snd_aloop" 1207 1208 static struct platform_driver loopback_driver = { 1209 .probe = loopback_probe, 1210 .remove = __devexit_p(loopback_remove), 1211 .driver = { 1212 .name = SND_LOOPBACK_DRIVER, 1213 .owner = THIS_MODULE, 1214 .pm = LOOPBACK_PM_OPS, 1215 }, 1216 }; 1217 1218 static void loopback_unregister_all(void) 1219 { 1220 int i; 1221 1222 for (i = 0; i < ARRAY_SIZE(devices); ++i) 1223 platform_device_unregister(devices[i]); 1224 platform_driver_unregister(&loopback_driver); 1225 } 1226 1227 static int __init alsa_card_loopback_init(void) 1228 { 1229 int i, err, cards; 1230 1231 err = platform_driver_register(&loopback_driver); 1232 if (err < 0) 1233 return err; 1234 1235 1236 cards = 0; 1237 for (i = 0; i < SNDRV_CARDS; i++) { 1238 struct platform_device *device; 1239 if (!enable[i]) 1240 continue; 1241 device = platform_device_register_simple(SND_LOOPBACK_DRIVER, 1242 i, NULL, 0); 1243 if (IS_ERR(device)) 1244 continue; 1245 if (!platform_get_drvdata(device)) { 1246 platform_device_unregister(device); 1247 continue; 1248 } 1249 devices[i] = device; 1250 cards++; 1251 } 1252 if (!cards) { 1253 #ifdef MODULE 1254 printk(KERN_ERR "aloop: No loopback enabled\n"); 1255 #endif 1256 loopback_unregister_all(); 1257 return -ENODEV; 1258 } 1259 return 0; 1260 } 1261 1262 static void __exit alsa_card_loopback_exit(void) 1263 { 1264 loopback_unregister_all(); 1265 } 1266 1267 module_init(alsa_card_loopback_init) 1268 module_exit(alsa_card_loopback_exit) 1269