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 45MODULE_AUTHOR("Jaroslav Kysela <perex@perex.cz>"); 46MODULE_DESCRIPTION("A loopback soundcard"); 47MODULE_LICENSE("GPL"); 48MODULE_SUPPORTED_DEVICE("{{ALSA,Loopback soundcard}}"); 49 50#define MAX_PCM_SUBSTREAMS 8 51 52static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX; /* Index 0-MAX */ 53static char *id[SNDRV_CARDS] = SNDRV_DEFAULT_STR; /* ID for this card */ 54static bool enable[SNDRV_CARDS] = {1, [1 ... (SNDRV_CARDS - 1)] = 0}; 55static int pcm_substreams[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 8}; 56static int pcm_notify[SNDRV_CARDS]; 57 58module_param_array(index, int, NULL, 0444); 59MODULE_PARM_DESC(index, "Index value for loopback soundcard."); 60module_param_array(id, charp, NULL, 0444); 61MODULE_PARM_DESC(id, "ID string for loopback soundcard."); 62module_param_array(enable, bool, NULL, 0444); 63MODULE_PARM_DESC(enable, "Enable this loopback soundcard."); 64module_param_array(pcm_substreams, int, NULL, 0444); 65MODULE_PARM_DESC(pcm_substreams, "PCM substreams # (1-8) for loopback driver."); 66module_param_array(pcm_notify, int, NULL, 0444); 67MODULE_PARM_DESC(pcm_notify, "Break capture when PCM format/rate/channels changes."); 68 69#define NO_PITCH 100000 70 71struct loopback_pcm; 72 73struct 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 83struct 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 95struct 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 103struct 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 125static struct platform_device *devices[SNDRV_CARDS]; 126 127static 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 138static 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 149static 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 158static inline unsigned int get_notify(struct loopback_pcm *dpcm) 159{ 160 return get_setup(dpcm)->notify; 161} 162 163static inline unsigned int get_rate_shift(struct loopback_pcm *dpcm) 164{ 165 return get_setup(dpcm)->rate_shift; 166} 167 168/* call in cable->lock */ 169static void loopback_timer_start(struct loopback_pcm *dpcm) 170{ 171 unsigned long tick; 172 unsigned int rate_shift = get_rate_shift(dpcm); 173 174 if (rate_shift != dpcm->pcm_rate_shift) { 175 dpcm->pcm_rate_shift = rate_shift; 176 dpcm->period_size_frac = frac_pos(dpcm, dpcm->pcm_period_size); 177 } 178 if (dpcm->period_size_frac <= dpcm->irq_pos) { 179 dpcm->irq_pos %= dpcm->period_size_frac; 180 dpcm->period_update_pending = 1; 181 } 182 tick = dpcm->period_size_frac - dpcm->irq_pos; 183 tick = (tick + dpcm->pcm_bps - 1) / dpcm->pcm_bps; 184 mod_timer(&dpcm->timer, jiffies + tick); 185} 186 187/* call in cable->lock */ 188static inline void loopback_timer_stop(struct loopback_pcm *dpcm) 189{ 190 del_timer(&dpcm->timer); 191 dpcm->timer.expires = 0; 192} 193 194#define CABLE_VALID_PLAYBACK (1 << SNDRV_PCM_STREAM_PLAYBACK) 195#define CABLE_VALID_CAPTURE (1 << SNDRV_PCM_STREAM_CAPTURE) 196#define CABLE_VALID_BOTH (CABLE_VALID_PLAYBACK|CABLE_VALID_CAPTURE) 197 198static int loopback_check_format(struct loopback_cable *cable, int stream) 199{ 200 struct snd_pcm_runtime *runtime, *cruntime; 201 struct loopback_setup *setup; 202 struct snd_card *card; 203 int check; 204 205 if (cable->valid != CABLE_VALID_BOTH) { 206 if (stream == SNDRV_PCM_STREAM_PLAYBACK) 207 goto __notify; 208 return 0; 209 } 210 runtime = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]-> 211 substream->runtime; 212 cruntime = cable->streams[SNDRV_PCM_STREAM_CAPTURE]-> 213 substream->runtime; 214 check = runtime->format != cruntime->format || 215 runtime->rate != cruntime->rate || 216 runtime->channels != cruntime->channels; 217 if (!check) 218 return 0; 219 if (stream == SNDRV_PCM_STREAM_CAPTURE) { 220 return -EIO; 221 } else { 222 snd_pcm_stop(cable->streams[SNDRV_PCM_STREAM_CAPTURE]-> 223 substream, SNDRV_PCM_STATE_DRAINING); 224 __notify: 225 runtime = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]-> 226 substream->runtime; 227 setup = get_setup(cable->streams[SNDRV_PCM_STREAM_PLAYBACK]); 228 card = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]->loopback->card; 229 if (setup->format != runtime->format) { 230 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE, 231 &setup->format_id); 232 setup->format = runtime->format; 233 } 234 if (setup->rate != runtime->rate) { 235 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE, 236 &setup->rate_id); 237 setup->rate = runtime->rate; 238 } 239 if (setup->channels != runtime->channels) { 240 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE, 241 &setup->channels_id); 242 setup->channels = runtime->channels; 243 } 244 } 245 return 0; 246} 247 248static void loopback_active_notify(struct loopback_pcm *dpcm) 249{ 250 snd_ctl_notify(dpcm->loopback->card, 251 SNDRV_CTL_EVENT_MASK_VALUE, 252 &get_setup(dpcm)->active_id); 253} 254 255static int loopback_trigger(struct snd_pcm_substream *substream, int cmd) 256{ 257 struct snd_pcm_runtime *runtime = substream->runtime; 258 struct loopback_pcm *dpcm = runtime->private_data; 259 struct loopback_cable *cable = dpcm->cable; 260 int err, stream = 1 << substream->stream; 261 262 switch (cmd) { 263 case SNDRV_PCM_TRIGGER_START: 264 err = loopback_check_format(cable, substream->stream); 265 if (err < 0) 266 return err; 267 dpcm->last_jiffies = jiffies; 268 dpcm->pcm_rate_shift = 0; 269 dpcm->last_drift = 0; 270 spin_lock(&cable->lock); 271 cable->running |= stream; 272 cable->pause &= ~stream; 273 loopback_timer_start(dpcm); 274 spin_unlock(&cable->lock); 275 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) 276 loopback_active_notify(dpcm); 277 break; 278 case SNDRV_PCM_TRIGGER_STOP: 279 spin_lock(&cable->lock); 280 cable->running &= ~stream; 281 cable->pause &= ~stream; 282 loopback_timer_stop(dpcm); 283 spin_unlock(&cable->lock); 284 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) 285 loopback_active_notify(dpcm); 286 break; 287 case SNDRV_PCM_TRIGGER_PAUSE_PUSH: 288 case SNDRV_PCM_TRIGGER_SUSPEND: 289 spin_lock(&cable->lock); 290 cable->pause |= stream; 291 loopback_timer_stop(dpcm); 292 spin_unlock(&cable->lock); 293 break; 294 case SNDRV_PCM_TRIGGER_PAUSE_RELEASE: 295 case SNDRV_PCM_TRIGGER_RESUME: 296 spin_lock(&cable->lock); 297 dpcm->last_jiffies = jiffies; 298 cable->pause &= ~stream; 299 loopback_timer_start(dpcm); 300 spin_unlock(&cable->lock); 301 break; 302 default: 303 return -EINVAL; 304 } 305 return 0; 306} 307 308static void params_change_substream(struct loopback_pcm *dpcm, 309 struct snd_pcm_runtime *runtime) 310{ 311 struct snd_pcm_runtime *dst_runtime; 312 313 if (dpcm == NULL || dpcm->substream == NULL) 314 return; 315 dst_runtime = dpcm->substream->runtime; 316 if (dst_runtime == NULL) 317 return; 318 dst_runtime->hw = dpcm->cable->hw; 319} 320 321static void params_change(struct snd_pcm_substream *substream) 322{ 323 struct snd_pcm_runtime *runtime = substream->runtime; 324 struct loopback_pcm *dpcm = runtime->private_data; 325 struct loopback_cable *cable = dpcm->cable; 326 327 cable->hw.formats = pcm_format_to_bits(runtime->format); 328 cable->hw.rate_min = runtime->rate; 329 cable->hw.rate_max = runtime->rate; 330 cable->hw.channels_min = runtime->channels; 331 cable->hw.channels_max = runtime->channels; 332 params_change_substream(cable->streams[SNDRV_PCM_STREAM_PLAYBACK], 333 runtime); 334 params_change_substream(cable->streams[SNDRV_PCM_STREAM_CAPTURE], 335 runtime); 336} 337 338static int loopback_prepare(struct snd_pcm_substream *substream) 339{ 340 struct snd_pcm_runtime *runtime = substream->runtime; 341 struct loopback_pcm *dpcm = runtime->private_data; 342 struct loopback_cable *cable = dpcm->cable; 343 int bps, salign; 344 345 salign = (snd_pcm_format_width(runtime->format) * 346 runtime->channels) / 8; 347 bps = salign * runtime->rate; 348 if (bps <= 0 || salign <= 0) 349 return -EINVAL; 350 351 dpcm->buf_pos = 0; 352 dpcm->pcm_buffer_size = frames_to_bytes(runtime, runtime->buffer_size); 353 if (substream->stream == SNDRV_PCM_STREAM_CAPTURE) { 354 /* clear capture buffer */ 355 dpcm->silent_size = dpcm->pcm_buffer_size; 356 snd_pcm_format_set_silence(runtime->format, runtime->dma_area, 357 runtime->buffer_size * runtime->channels); 358 } 359 360 dpcm->irq_pos = 0; 361 dpcm->period_update_pending = 0; 362 dpcm->pcm_bps = bps; 363 dpcm->pcm_salign = salign; 364 dpcm->pcm_period_size = frames_to_bytes(runtime, runtime->period_size); 365 366 mutex_lock(&dpcm->loopback->cable_lock); 367 if (!(cable->valid & ~(1 << substream->stream)) || 368 (get_setup(dpcm)->notify && 369 substream->stream == SNDRV_PCM_STREAM_PLAYBACK)) 370 params_change(substream); 371 cable->valid |= 1 << substream->stream; 372 mutex_unlock(&dpcm->loopback->cable_lock); 373 374 return 0; 375} 376 377static void clear_capture_buf(struct loopback_pcm *dpcm, unsigned int bytes) 378{ 379 struct snd_pcm_runtime *runtime = dpcm->substream->runtime; 380 char *dst = runtime->dma_area; 381 unsigned int dst_off = dpcm->buf_pos; 382 383 if (dpcm->silent_size >= dpcm->pcm_buffer_size) 384 return; 385 if (dpcm->silent_size + bytes > dpcm->pcm_buffer_size) 386 bytes = dpcm->pcm_buffer_size - dpcm->silent_size; 387 388 for (;;) { 389 unsigned int size = bytes; 390 if (dst_off + size > dpcm->pcm_buffer_size) 391 size = dpcm->pcm_buffer_size - dst_off; 392 snd_pcm_format_set_silence(runtime->format, dst + dst_off, 393 bytes_to_frames(runtime, size) * 394 runtime->channels); 395 dpcm->silent_size += size; 396 bytes -= size; 397 if (!bytes) 398 break; 399 dst_off = 0; 400 } 401} 402 403static void copy_play_buf(struct loopback_pcm *play, 404 struct loopback_pcm *capt, 405 unsigned int bytes) 406{ 407 struct snd_pcm_runtime *runtime = play->substream->runtime; 408 char *src = runtime->dma_area; 409 char *dst = capt->substream->runtime->dma_area; 410 unsigned int src_off = play->buf_pos; 411 unsigned int dst_off = capt->buf_pos; 412 unsigned int clear_bytes = 0; 413 414 /* check if playback is draining, trim the capture copy size 415 * when our pointer is at the end of playback ring buffer */ 416 if (runtime->status->state == SNDRV_PCM_STATE_DRAINING && 417 snd_pcm_playback_hw_avail(runtime) < runtime->buffer_size) { 418 snd_pcm_uframes_t appl_ptr, appl_ptr1, diff; 419 appl_ptr = appl_ptr1 = runtime->control->appl_ptr; 420 appl_ptr1 -= appl_ptr1 % runtime->buffer_size; 421 appl_ptr1 += play->buf_pos / play->pcm_salign; 422 if (appl_ptr < appl_ptr1) 423 appl_ptr1 -= runtime->buffer_size; 424 diff = (appl_ptr - appl_ptr1) * play->pcm_salign; 425 if (diff < bytes) { 426 clear_bytes = bytes - diff; 427 bytes = diff; 428 } 429 } 430 431 for (;;) { 432 unsigned int size = bytes; 433 if (src_off + size > play->pcm_buffer_size) 434 size = play->pcm_buffer_size - src_off; 435 if (dst_off + size > capt->pcm_buffer_size) 436 size = capt->pcm_buffer_size - dst_off; 437 memcpy(dst + dst_off, src + src_off, size); 438 capt->silent_size = 0; 439 bytes -= size; 440 if (!bytes) 441 break; 442 src_off = (src_off + size) % play->pcm_buffer_size; 443 dst_off = (dst_off + size) % capt->pcm_buffer_size; 444 } 445 446 if (clear_bytes > 0) { 447 clear_capture_buf(capt, clear_bytes); 448 capt->silent_size = 0; 449 } 450} 451 452static inline unsigned int bytepos_delta(struct loopback_pcm *dpcm, 453 unsigned int jiffies_delta) 454{ 455 unsigned long last_pos; 456 unsigned int delta; 457 458 last_pos = byte_pos(dpcm, dpcm->irq_pos); 459 dpcm->irq_pos += jiffies_delta * dpcm->pcm_bps; 460 delta = byte_pos(dpcm, dpcm->irq_pos) - last_pos; 461 if (delta >= dpcm->last_drift) 462 delta -= dpcm->last_drift; 463 dpcm->last_drift = 0; 464 if (dpcm->irq_pos >= dpcm->period_size_frac) { 465 dpcm->irq_pos %= dpcm->period_size_frac; 466 dpcm->period_update_pending = 1; 467 } 468 return delta; 469} 470 471static inline void bytepos_finish(struct loopback_pcm *dpcm, 472 unsigned int delta) 473{ 474 dpcm->buf_pos += delta; 475 dpcm->buf_pos %= dpcm->pcm_buffer_size; 476} 477 478/* call in cable->lock */ 479static unsigned int loopback_pos_update(struct loopback_cable *cable) 480{ 481 struct loopback_pcm *dpcm_play = 482 cable->streams[SNDRV_PCM_STREAM_PLAYBACK]; 483 struct loopback_pcm *dpcm_capt = 484 cable->streams[SNDRV_PCM_STREAM_CAPTURE]; 485 unsigned long delta_play = 0, delta_capt = 0; 486 unsigned int running, count1, count2; 487 488 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 count1 = bytepos_delta(dpcm_play, delta_play - delta_capt); 504 bytepos_finish(dpcm_play, count1); 505 delta_play = delta_capt; 506 } else if (delta_play < delta_capt) { 507 count1 = bytepos_delta(dpcm_capt, delta_capt - delta_play); 508 clear_capture_buf(dpcm_capt, count1); 509 bytepos_finish(dpcm_capt, count1); 510 delta_capt = delta_play; 511 } 512 513 if (delta_play == 0 && delta_capt == 0) 514 goto unlock; 515 516 /* note delta_capt == delta_play at this moment */ 517 count1 = bytepos_delta(dpcm_play, delta_play); 518 count2 = bytepos_delta(dpcm_capt, delta_capt); 519 if (count1 < count2) { 520 dpcm_capt->last_drift = count2 - count1; 521 count1 = count2; 522 } else if (count1 > count2) { 523 dpcm_play->last_drift = count1 - count2; 524 } 525 copy_play_buf(dpcm_play, dpcm_capt, count1); 526 bytepos_finish(dpcm_play, count1); 527 bytepos_finish(dpcm_capt, count1); 528 unlock: 529 return running; 530} 531 532static void loopback_timer_function(unsigned long data) 533{ 534 struct loopback_pcm *dpcm = (struct loopback_pcm *)data; 535 unsigned long flags; 536 537 spin_lock_irqsave(&dpcm->cable->lock, flags); 538 if (loopback_pos_update(dpcm->cable) & (1 << dpcm->substream->stream)) { 539 loopback_timer_start(dpcm); 540 if (dpcm->period_update_pending) { 541 dpcm->period_update_pending = 0; 542 spin_unlock_irqrestore(&dpcm->cable->lock, flags); 543 /* need to unlock before calling below */ 544 snd_pcm_period_elapsed(dpcm->substream); 545 return; 546 } 547 } 548 spin_unlock_irqrestore(&dpcm->cable->lock, flags); 549} 550 551static snd_pcm_uframes_t loopback_pointer(struct snd_pcm_substream *substream) 552{ 553 struct snd_pcm_runtime *runtime = substream->runtime; 554 struct loopback_pcm *dpcm = runtime->private_data; 555 snd_pcm_uframes_t pos; 556 557 spin_lock(&dpcm->cable->lock); 558 loopback_pos_update(dpcm->cable); 559 pos = dpcm->buf_pos; 560 spin_unlock(&dpcm->cable->lock); 561 return bytes_to_frames(runtime, pos); 562} 563 564static struct snd_pcm_hardware loopback_pcm_hardware = 565{ 566 .info = (SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_MMAP | 567 SNDRV_PCM_INFO_MMAP_VALID | SNDRV_PCM_INFO_PAUSE | 568 SNDRV_PCM_INFO_RESUME), 569 .formats = (SNDRV_PCM_FMTBIT_S16_LE | SNDRV_PCM_FMTBIT_S16_BE | 570 SNDRV_PCM_FMTBIT_S32_LE | SNDRV_PCM_FMTBIT_S32_BE | 571 SNDRV_PCM_FMTBIT_FLOAT_LE | SNDRV_PCM_FMTBIT_FLOAT_BE), 572 .rates = SNDRV_PCM_RATE_CONTINUOUS | SNDRV_PCM_RATE_8000_192000, 573 .rate_min = 8000, 574 .rate_max = 192000, 575 .channels_min = 1, 576 .channels_max = 32, 577 .buffer_bytes_max = 2 * 1024 * 1024, 578 .period_bytes_min = 64, 579 /* note check overflow in frac_pos() using pcm_rate_shift before 580 changing period_bytes_max value */ 581 .period_bytes_max = 1024 * 1024, 582 .periods_min = 1, 583 .periods_max = 1024, 584 .fifo_size = 0, 585}; 586 587static void loopback_runtime_free(struct snd_pcm_runtime *runtime) 588{ 589 struct loopback_pcm *dpcm = runtime->private_data; 590 kfree(dpcm); 591} 592 593static int loopback_hw_params(struct snd_pcm_substream *substream, 594 struct snd_pcm_hw_params *params) 595{ 596 return snd_pcm_lib_alloc_vmalloc_buffer(substream, 597 params_buffer_bytes(params)); 598} 599 600static int loopback_hw_free(struct snd_pcm_substream *substream) 601{ 602 struct snd_pcm_runtime *runtime = substream->runtime; 603 struct loopback_pcm *dpcm = runtime->private_data; 604 struct loopback_cable *cable = dpcm->cable; 605 606 mutex_lock(&dpcm->loopback->cable_lock); 607 cable->valid &= ~(1 << substream->stream); 608 mutex_unlock(&dpcm->loopback->cable_lock); 609 return snd_pcm_lib_free_vmalloc_buffer(substream); 610} 611 612static unsigned int get_cable_index(struct snd_pcm_substream *substream) 613{ 614 if (!substream->pcm->device) 615 return substream->stream; 616 else 617 return !substream->stream; 618} 619 620static int rule_format(struct snd_pcm_hw_params *params, 621 struct snd_pcm_hw_rule *rule) 622{ 623 624 struct snd_pcm_hardware *hw = rule->private; 625 struct snd_mask *maskp = hw_param_mask(params, rule->var); 626 627 maskp->bits[0] &= (u_int32_t)hw->formats; 628 maskp->bits[1] &= (u_int32_t)(hw->formats >> 32); 629 memset(maskp->bits + 2, 0, (SNDRV_MASK_MAX-64) / 8); /* clear rest */ 630 if (! maskp->bits[0] && ! maskp->bits[1]) 631 return -EINVAL; 632 return 0; 633} 634 635static int rule_rate(struct snd_pcm_hw_params *params, 636 struct snd_pcm_hw_rule *rule) 637{ 638 struct snd_pcm_hardware *hw = rule->private; 639 struct snd_interval t; 640 641 t.min = hw->rate_min; 642 t.max = hw->rate_max; 643 t.openmin = t.openmax = 0; 644 t.integer = 0; 645 return snd_interval_refine(hw_param_interval(params, rule->var), &t); 646} 647 648static int rule_channels(struct snd_pcm_hw_params *params, 649 struct snd_pcm_hw_rule *rule) 650{ 651 struct snd_pcm_hardware *hw = rule->private; 652 struct snd_interval t; 653 654 t.min = hw->channels_min; 655 t.max = hw->channels_max; 656 t.openmin = t.openmax = 0; 657 t.integer = 0; 658 return snd_interval_refine(hw_param_interval(params, rule->var), &t); 659} 660 661static int loopback_open(struct snd_pcm_substream *substream) 662{ 663 struct snd_pcm_runtime *runtime = substream->runtime; 664 struct loopback *loopback = substream->private_data; 665 struct loopback_pcm *dpcm; 666 struct loopback_cable *cable; 667 int err = 0; 668 int dev = get_cable_index(substream); 669 670 mutex_lock(&loopback->cable_lock); 671 dpcm = kzalloc(sizeof(*dpcm), GFP_KERNEL); 672 if (!dpcm) { 673 err = -ENOMEM; 674 goto unlock; 675 } 676 dpcm->loopback = loopback; 677 dpcm->substream = substream; 678 setup_timer(&dpcm->timer, loopback_timer_function, 679 (unsigned long)dpcm); 680 681 cable = loopback->cables[substream->number][dev]; 682 if (!cable) { 683 cable = kzalloc(sizeof(*cable), GFP_KERNEL); 684 if (!cable) { 685 kfree(dpcm); 686 err = -ENOMEM; 687 goto unlock; 688 } 689 spin_lock_init(&cable->lock); 690 cable->hw = loopback_pcm_hardware; 691 loopback->cables[substream->number][dev] = cable; 692 } 693 dpcm->cable = cable; 694 cable->streams[substream->stream] = dpcm; 695 696 snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS); 697 698 /* use dynamic rules based on actual runtime->hw values */ 699 /* note that the default rules created in the PCM midlevel code */ 700 /* are cached -> they do not reflect the actual state */ 701 err = snd_pcm_hw_rule_add(runtime, 0, 702 SNDRV_PCM_HW_PARAM_FORMAT, 703 rule_format, &runtime->hw, 704 SNDRV_PCM_HW_PARAM_FORMAT, -1); 705 if (err < 0) 706 goto unlock; 707 err = snd_pcm_hw_rule_add(runtime, 0, 708 SNDRV_PCM_HW_PARAM_RATE, 709 rule_rate, &runtime->hw, 710 SNDRV_PCM_HW_PARAM_RATE, -1); 711 if (err < 0) 712 goto unlock; 713 err = snd_pcm_hw_rule_add(runtime, 0, 714 SNDRV_PCM_HW_PARAM_CHANNELS, 715 rule_channels, &runtime->hw, 716 SNDRV_PCM_HW_PARAM_CHANNELS, -1); 717 if (err < 0) 718 goto unlock; 719 720 runtime->private_data = dpcm; 721 runtime->private_free = loopback_runtime_free; 722 if (get_notify(dpcm)) 723 runtime->hw = loopback_pcm_hardware; 724 else 725 runtime->hw = cable->hw; 726 unlock: 727 mutex_unlock(&loopback->cable_lock); 728 return err; 729} 730 731static int loopback_close(struct snd_pcm_substream *substream) 732{ 733 struct loopback *loopback = substream->private_data; 734 struct loopback_pcm *dpcm = substream->runtime->private_data; 735 struct loopback_cable *cable; 736 int dev = get_cable_index(substream); 737 738 loopback_timer_stop(dpcm); 739 mutex_lock(&loopback->cable_lock); 740 cable = loopback->cables[substream->number][dev]; 741 if (cable->streams[!substream->stream]) { 742 /* other stream is still alive */ 743 cable->streams[substream->stream] = NULL; 744 } else { 745 /* free the cable */ 746 loopback->cables[substream->number][dev] = NULL; 747 kfree(cable); 748 } 749 mutex_unlock(&loopback->cable_lock); 750 return 0; 751} 752 753static struct snd_pcm_ops loopback_playback_ops = { 754 .open = loopback_open, 755 .close = loopback_close, 756 .ioctl = snd_pcm_lib_ioctl, 757 .hw_params = loopback_hw_params, 758 .hw_free = loopback_hw_free, 759 .prepare = loopback_prepare, 760 .trigger = loopback_trigger, 761 .pointer = loopback_pointer, 762 .page = snd_pcm_lib_get_vmalloc_page, 763 .mmap = snd_pcm_lib_mmap_vmalloc, 764}; 765 766static struct snd_pcm_ops loopback_capture_ops = { 767 .open = loopback_open, 768 .close = loopback_close, 769 .ioctl = snd_pcm_lib_ioctl, 770 .hw_params = loopback_hw_params, 771 .hw_free = loopback_hw_free, 772 .prepare = loopback_prepare, 773 .trigger = loopback_trigger, 774 .pointer = loopback_pointer, 775 .page = snd_pcm_lib_get_vmalloc_page, 776 .mmap = snd_pcm_lib_mmap_vmalloc, 777}; 778 779static int loopback_pcm_new(struct loopback *loopback, 780 int device, int substreams) 781{ 782 struct snd_pcm *pcm; 783 int err; 784 785 err = snd_pcm_new(loopback->card, "Loopback PCM", device, 786 substreams, substreams, &pcm); 787 if (err < 0) 788 return err; 789 snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &loopback_playback_ops); 790 snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &loopback_capture_ops); 791 792 pcm->private_data = loopback; 793 pcm->info_flags = 0; 794 strcpy(pcm->name, "Loopback PCM"); 795 796 loopback->pcm[device] = pcm; 797 return 0; 798} 799 800static int loopback_rate_shift_info(struct snd_kcontrol *kcontrol, 801 struct snd_ctl_elem_info *uinfo) 802{ 803 uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER; 804 uinfo->count = 1; 805 uinfo->value.integer.min = 80000; 806 uinfo->value.integer.max = 120000; 807 uinfo->value.integer.step = 1; 808 return 0; 809} 810 811static int loopback_rate_shift_get(struct snd_kcontrol *kcontrol, 812 struct snd_ctl_elem_value *ucontrol) 813{ 814 struct loopback *loopback = snd_kcontrol_chip(kcontrol); 815 816 ucontrol->value.integer.value[0] = 817 loopback->setup[kcontrol->id.subdevice] 818 [kcontrol->id.device].rate_shift; 819 return 0; 820} 821 822static int loopback_rate_shift_put(struct snd_kcontrol *kcontrol, 823 struct snd_ctl_elem_value *ucontrol) 824{ 825 struct loopback *loopback = snd_kcontrol_chip(kcontrol); 826 unsigned int val; 827 int change = 0; 828 829 val = ucontrol->value.integer.value[0]; 830 if (val < 80000) 831 val = 80000; 832 if (val > 120000) 833 val = 120000; 834 mutex_lock(&loopback->cable_lock); 835 if (val != loopback->setup[kcontrol->id.subdevice] 836 [kcontrol->id.device].rate_shift) { 837 loopback->setup[kcontrol->id.subdevice] 838 [kcontrol->id.device].rate_shift = val; 839 change = 1; 840 } 841 mutex_unlock(&loopback->cable_lock); 842 return change; 843} 844 845static int loopback_notify_get(struct snd_kcontrol *kcontrol, 846 struct snd_ctl_elem_value *ucontrol) 847{ 848 struct loopback *loopback = snd_kcontrol_chip(kcontrol); 849 850 ucontrol->value.integer.value[0] = 851 loopback->setup[kcontrol->id.subdevice] 852 [kcontrol->id.device].notify; 853 return 0; 854} 855 856static int loopback_notify_put(struct snd_kcontrol *kcontrol, 857 struct snd_ctl_elem_value *ucontrol) 858{ 859 struct loopback *loopback = snd_kcontrol_chip(kcontrol); 860 unsigned int val; 861 int change = 0; 862 863 val = ucontrol->value.integer.value[0] ? 1 : 0; 864 if (val != loopback->setup[kcontrol->id.subdevice] 865 [kcontrol->id.device].notify) { 866 loopback->setup[kcontrol->id.subdevice] 867 [kcontrol->id.device].notify = val; 868 change = 1; 869 } 870 return change; 871} 872 873static int loopback_active_get(struct snd_kcontrol *kcontrol, 874 struct snd_ctl_elem_value *ucontrol) 875{ 876 struct loopback *loopback = snd_kcontrol_chip(kcontrol); 877 struct loopback_cable *cable = loopback->cables 878 [kcontrol->id.subdevice][kcontrol->id.device ^ 1]; 879 unsigned int val = 0; 880 881 if (cable != NULL) 882 val = (cable->running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) ? 883 1 : 0; 884 ucontrol->value.integer.value[0] = val; 885 return 0; 886} 887 888static int loopback_format_info(struct snd_kcontrol *kcontrol, 889 struct snd_ctl_elem_info *uinfo) 890{ 891 uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER; 892 uinfo->count = 1; 893 uinfo->value.integer.min = 0; 894 uinfo->value.integer.max = SNDRV_PCM_FORMAT_LAST; 895 uinfo->value.integer.step = 1; 896 return 0; 897} 898 899static int loopback_format_get(struct snd_kcontrol *kcontrol, 900 struct snd_ctl_elem_value *ucontrol) 901{ 902 struct loopback *loopback = snd_kcontrol_chip(kcontrol); 903 904 ucontrol->value.integer.value[0] = 905 loopback->setup[kcontrol->id.subdevice] 906 [kcontrol->id.device].format; 907 return 0; 908} 909 910static int loopback_rate_info(struct snd_kcontrol *kcontrol, 911 struct snd_ctl_elem_info *uinfo) 912{ 913 uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER; 914 uinfo->count = 1; 915 uinfo->value.integer.min = 0; 916 uinfo->value.integer.max = 192000; 917 uinfo->value.integer.step = 1; 918 return 0; 919} 920 921static int loopback_rate_get(struct snd_kcontrol *kcontrol, 922 struct snd_ctl_elem_value *ucontrol) 923{ 924 struct loopback *loopback = snd_kcontrol_chip(kcontrol); 925 926 ucontrol->value.integer.value[0] = 927 loopback->setup[kcontrol->id.subdevice] 928 [kcontrol->id.device].rate; 929 return 0; 930} 931 932static int loopback_channels_info(struct snd_kcontrol *kcontrol, 933 struct snd_ctl_elem_info *uinfo) 934{ 935 uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER; 936 uinfo->count = 1; 937 uinfo->value.integer.min = 1; 938 uinfo->value.integer.max = 1024; 939 uinfo->value.integer.step = 1; 940 return 0; 941} 942 943static int loopback_channels_get(struct snd_kcontrol *kcontrol, 944 struct snd_ctl_elem_value *ucontrol) 945{ 946 struct loopback *loopback = snd_kcontrol_chip(kcontrol); 947 948 ucontrol->value.integer.value[0] = 949 loopback->setup[kcontrol->id.subdevice] 950 [kcontrol->id.device].channels; 951 return 0; 952} 953 954static struct snd_kcontrol_new loopback_controls[] = { 955{ 956 .iface = SNDRV_CTL_ELEM_IFACE_PCM, 957 .name = "PCM Rate Shift 100000", 958 .info = loopback_rate_shift_info, 959 .get = loopback_rate_shift_get, 960 .put = loopback_rate_shift_put, 961}, 962{ 963 .iface = SNDRV_CTL_ELEM_IFACE_PCM, 964 .name = "PCM Notify", 965 .info = snd_ctl_boolean_mono_info, 966 .get = loopback_notify_get, 967 .put = loopback_notify_put, 968}, 969#define ACTIVE_IDX 2 970{ 971 .access = SNDRV_CTL_ELEM_ACCESS_READ, 972 .iface = SNDRV_CTL_ELEM_IFACE_PCM, 973 .name = "PCM Slave Active", 974 .info = snd_ctl_boolean_mono_info, 975 .get = loopback_active_get, 976}, 977#define FORMAT_IDX 3 978{ 979 .access = SNDRV_CTL_ELEM_ACCESS_READ, 980 .iface = SNDRV_CTL_ELEM_IFACE_PCM, 981 .name = "PCM Slave Format", 982 .info = loopback_format_info, 983 .get = loopback_format_get 984}, 985#define RATE_IDX 4 986{ 987 .access = SNDRV_CTL_ELEM_ACCESS_READ, 988 .iface = SNDRV_CTL_ELEM_IFACE_PCM, 989 .name = "PCM Slave Rate", 990 .info = loopback_rate_info, 991 .get = loopback_rate_get 992}, 993#define CHANNELS_IDX 5 994{ 995 .access = SNDRV_CTL_ELEM_ACCESS_READ, 996 .iface = SNDRV_CTL_ELEM_IFACE_PCM, 997 .name = "PCM Slave Channels", 998 .info = loopback_channels_info, 999 .get = loopback_channels_get 1000} 1001}; 1002 1003static int loopback_mixer_new(struct loopback *loopback, int notify) 1004{ 1005 struct snd_card *card = loopback->card; 1006 struct snd_pcm *pcm; 1007 struct snd_kcontrol *kctl; 1008 struct loopback_setup *setup; 1009 int err, dev, substr, substr_count, idx; 1010 1011 strcpy(card->mixername, "Loopback Mixer"); 1012 for (dev = 0; dev < 2; dev++) { 1013 pcm = loopback->pcm[dev]; 1014 substr_count = 1015 pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream_count; 1016 for (substr = 0; substr < substr_count; substr++) { 1017 setup = &loopback->setup[substr][dev]; 1018 setup->notify = notify; 1019 setup->rate_shift = NO_PITCH; 1020 setup->format = SNDRV_PCM_FORMAT_S16_LE; 1021 setup->rate = 48000; 1022 setup->channels = 2; 1023 for (idx = 0; idx < ARRAY_SIZE(loopback_controls); 1024 idx++) { 1025 kctl = snd_ctl_new1(&loopback_controls[idx], 1026 loopback); 1027 if (!kctl) 1028 return -ENOMEM; 1029 kctl->id.device = dev; 1030 kctl->id.subdevice = substr; 1031 switch (idx) { 1032 case ACTIVE_IDX: 1033 setup->active_id = kctl->id; 1034 break; 1035 case FORMAT_IDX: 1036 setup->format_id = kctl->id; 1037 break; 1038 case RATE_IDX: 1039 setup->rate_id = kctl->id; 1040 break; 1041 case CHANNELS_IDX: 1042 setup->channels_id = kctl->id; 1043 break; 1044 default: 1045 break; 1046 } 1047 err = snd_ctl_add(card, kctl); 1048 if (err < 0) 1049 return err; 1050 } 1051 } 1052 } 1053 return 0; 1054} 1055 1056#ifdef CONFIG_PROC_FS 1057 1058static void print_dpcm_info(struct snd_info_buffer *buffer, 1059 struct loopback_pcm *dpcm, 1060 const char *id) 1061{ 1062 snd_iprintf(buffer, " %s\n", id); 1063 if (dpcm == NULL) { 1064 snd_iprintf(buffer, " inactive\n"); 1065 return; 1066 } 1067 snd_iprintf(buffer, " buffer_size:\t%u\n", dpcm->pcm_buffer_size); 1068 snd_iprintf(buffer, " buffer_pos:\t\t%u\n", dpcm->buf_pos); 1069 snd_iprintf(buffer, " silent_size:\t%u\n", dpcm->silent_size); 1070 snd_iprintf(buffer, " period_size:\t%u\n", dpcm->pcm_period_size); 1071 snd_iprintf(buffer, " bytes_per_sec:\t%u\n", dpcm->pcm_bps); 1072 snd_iprintf(buffer, " sample_align:\t%u\n", dpcm->pcm_salign); 1073 snd_iprintf(buffer, " rate_shift:\t\t%u\n", dpcm->pcm_rate_shift); 1074 snd_iprintf(buffer, " update_pending:\t%u\n", 1075 dpcm->period_update_pending); 1076 snd_iprintf(buffer, " irq_pos:\t\t%u\n", dpcm->irq_pos); 1077 snd_iprintf(buffer, " period_frac:\t%u\n", dpcm->period_size_frac); 1078 snd_iprintf(buffer, " last_jiffies:\t%lu (%lu)\n", 1079 dpcm->last_jiffies, jiffies); 1080 snd_iprintf(buffer, " timer_expires:\t%lu\n", dpcm->timer.expires); 1081} 1082 1083static void print_substream_info(struct snd_info_buffer *buffer, 1084 struct loopback *loopback, 1085 int sub, 1086 int num) 1087{ 1088 struct loopback_cable *cable = loopback->cables[sub][num]; 1089 1090 snd_iprintf(buffer, "Cable %i substream %i:\n", num, sub); 1091 if (cable == NULL) { 1092 snd_iprintf(buffer, " inactive\n"); 1093 return; 1094 } 1095 snd_iprintf(buffer, " valid: %u\n", cable->valid); 1096 snd_iprintf(buffer, " running: %u\n", cable->running); 1097 snd_iprintf(buffer, " pause: %u\n", cable->pause); 1098 print_dpcm_info(buffer, cable->streams[0], "Playback"); 1099 print_dpcm_info(buffer, cable->streams[1], "Capture"); 1100} 1101 1102static void print_cable_info(struct snd_info_entry *entry, 1103 struct snd_info_buffer *buffer) 1104{ 1105 struct loopback *loopback = entry->private_data; 1106 int sub, num; 1107 1108 mutex_lock(&loopback->cable_lock); 1109 num = entry->name[strlen(entry->name)-1]; 1110 num = num == '0' ? 0 : 1; 1111 for (sub = 0; sub < MAX_PCM_SUBSTREAMS; sub++) 1112 print_substream_info(buffer, loopback, sub, num); 1113 mutex_unlock(&loopback->cable_lock); 1114} 1115 1116static int loopback_proc_new(struct loopback *loopback, int cidx) 1117{ 1118 char name[32]; 1119 struct snd_info_entry *entry; 1120 int err; 1121 1122 snprintf(name, sizeof(name), "cable#%d", cidx); 1123 err = snd_card_proc_new(loopback->card, name, &entry); 1124 if (err < 0) 1125 return err; 1126 1127 snd_info_set_text_ops(entry, loopback, print_cable_info); 1128 return 0; 1129} 1130 1131#else /* !CONFIG_PROC_FS */ 1132 1133#define loopback_proc_new(loopback, cidx) do { } while (0) 1134 1135#endif 1136 1137static int loopback_probe(struct platform_device *devptr) 1138{ 1139 struct snd_card *card; 1140 struct loopback *loopback; 1141 int dev = devptr->id; 1142 int err; 1143 1144 err = snd_card_new(&devptr->dev, index[dev], id[dev], THIS_MODULE, 1145 sizeof(struct loopback), &card); 1146 if (err < 0) 1147 return err; 1148 loopback = card->private_data; 1149 1150 if (pcm_substreams[dev] < 1) 1151 pcm_substreams[dev] = 1; 1152 if (pcm_substreams[dev] > MAX_PCM_SUBSTREAMS) 1153 pcm_substreams[dev] = MAX_PCM_SUBSTREAMS; 1154 1155 loopback->card = card; 1156 mutex_init(&loopback->cable_lock); 1157 1158 err = loopback_pcm_new(loopback, 0, pcm_substreams[dev]); 1159 if (err < 0) 1160 goto __nodev; 1161 err = loopback_pcm_new(loopback, 1, pcm_substreams[dev]); 1162 if (err < 0) 1163 goto __nodev; 1164 err = loopback_mixer_new(loopback, pcm_notify[dev] ? 1 : 0); 1165 if (err < 0) 1166 goto __nodev; 1167 loopback_proc_new(loopback, 0); 1168 loopback_proc_new(loopback, 1); 1169 strcpy(card->driver, "Loopback"); 1170 strcpy(card->shortname, "Loopback"); 1171 sprintf(card->longname, "Loopback %i", dev + 1); 1172 err = snd_card_register(card); 1173 if (!err) { 1174 platform_set_drvdata(devptr, card); 1175 return 0; 1176 } 1177 __nodev: 1178 snd_card_free(card); 1179 return err; 1180} 1181 1182static int loopback_remove(struct platform_device *devptr) 1183{ 1184 snd_card_free(platform_get_drvdata(devptr)); 1185 return 0; 1186} 1187 1188#ifdef CONFIG_PM_SLEEP 1189static int loopback_suspend(struct device *pdev) 1190{ 1191 struct snd_card *card = dev_get_drvdata(pdev); 1192 struct loopback *loopback = card->private_data; 1193 1194 snd_power_change_state(card, SNDRV_CTL_POWER_D3hot); 1195 1196 snd_pcm_suspend_all(loopback->pcm[0]); 1197 snd_pcm_suspend_all(loopback->pcm[1]); 1198 return 0; 1199} 1200 1201static int loopback_resume(struct device *pdev) 1202{ 1203 struct snd_card *card = dev_get_drvdata(pdev); 1204 1205 snd_power_change_state(card, SNDRV_CTL_POWER_D0); 1206 return 0; 1207} 1208 1209static SIMPLE_DEV_PM_OPS(loopback_pm, loopback_suspend, loopback_resume); 1210#define LOOPBACK_PM_OPS &loopback_pm 1211#else 1212#define LOOPBACK_PM_OPS NULL 1213#endif 1214 1215#define SND_LOOPBACK_DRIVER "snd_aloop" 1216 1217static struct platform_driver loopback_driver = { 1218 .probe = loopback_probe, 1219 .remove = loopback_remove, 1220 .driver = { 1221 .name = SND_LOOPBACK_DRIVER, 1222 .pm = LOOPBACK_PM_OPS, 1223 }, 1224}; 1225 1226static void loopback_unregister_all(void) 1227{ 1228 int i; 1229 1230 for (i = 0; i < ARRAY_SIZE(devices); ++i) 1231 platform_device_unregister(devices[i]); 1232 platform_driver_unregister(&loopback_driver); 1233} 1234 1235static int __init alsa_card_loopback_init(void) 1236{ 1237 int i, err, cards; 1238 1239 err = platform_driver_register(&loopback_driver); 1240 if (err < 0) 1241 return err; 1242 1243 1244 cards = 0; 1245 for (i = 0; i < SNDRV_CARDS; i++) { 1246 struct platform_device *device; 1247 if (!enable[i]) 1248 continue; 1249 device = platform_device_register_simple(SND_LOOPBACK_DRIVER, 1250 i, NULL, 0); 1251 if (IS_ERR(device)) 1252 continue; 1253 if (!platform_get_drvdata(device)) { 1254 platform_device_unregister(device); 1255 continue; 1256 } 1257 devices[i] = device; 1258 cards++; 1259 } 1260 if (!cards) { 1261#ifdef MODULE 1262 printk(KERN_ERR "aloop: No loopback enabled\n"); 1263#endif 1264 loopback_unregister_all(); 1265 return -ENODEV; 1266 } 1267 return 0; 1268} 1269 1270static void __exit alsa_card_loopback_exit(void) 1271{ 1272 loopback_unregister_all(); 1273} 1274 1275module_init(alsa_card_loopback_init) 1276module_exit(alsa_card_loopback_exit) 1277