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 /* call in cable->lock */ 169 static 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 dpcm->timer.expires = jiffies + tick; 185 add_timer(&dpcm->timer); 186 } 187 188 /* call in cable->lock */ 189 static inline void loopback_timer_stop(struct loopback_pcm *dpcm) 190 { 191 del_timer(&dpcm->timer); 192 dpcm->timer.expires = 0; 193 } 194 195 #define CABLE_VALID_PLAYBACK (1 << SNDRV_PCM_STREAM_PLAYBACK) 196 #define CABLE_VALID_CAPTURE (1 << SNDRV_PCM_STREAM_CAPTURE) 197 #define CABLE_VALID_BOTH (CABLE_VALID_PLAYBACK|CABLE_VALID_CAPTURE) 198 199 static int loopback_check_format(struct loopback_cable *cable, int stream) 200 { 201 struct snd_pcm_runtime *runtime, *cruntime; 202 struct loopback_setup *setup; 203 struct snd_card *card; 204 int check; 205 206 if (cable->valid != CABLE_VALID_BOTH) { 207 if (stream == SNDRV_PCM_STREAM_PLAYBACK) 208 goto __notify; 209 return 0; 210 } 211 runtime = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]-> 212 substream->runtime; 213 cruntime = cable->streams[SNDRV_PCM_STREAM_CAPTURE]-> 214 substream->runtime; 215 check = runtime->format != cruntime->format || 216 runtime->rate != cruntime->rate || 217 runtime->channels != cruntime->channels; 218 if (!check) 219 return 0; 220 if (stream == SNDRV_PCM_STREAM_CAPTURE) { 221 return -EIO; 222 } else { 223 snd_pcm_stop(cable->streams[SNDRV_PCM_STREAM_CAPTURE]-> 224 substream, SNDRV_PCM_STATE_DRAINING); 225 __notify: 226 runtime = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]-> 227 substream->runtime; 228 setup = get_setup(cable->streams[SNDRV_PCM_STREAM_PLAYBACK]); 229 card = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]->loopback->card; 230 if (setup->format != runtime->format) { 231 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE, 232 &setup->format_id); 233 setup->format = runtime->format; 234 } 235 if (setup->rate != runtime->rate) { 236 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE, 237 &setup->rate_id); 238 setup->rate = runtime->rate; 239 } 240 if (setup->channels != runtime->channels) { 241 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE, 242 &setup->channels_id); 243 setup->channels = runtime->channels; 244 } 245 } 246 return 0; 247 } 248 249 static void loopback_active_notify(struct loopback_pcm *dpcm) 250 { 251 snd_ctl_notify(dpcm->loopback->card, 252 SNDRV_CTL_EVENT_MASK_VALUE, 253 &get_setup(dpcm)->active_id); 254 } 255 256 static int loopback_trigger(struct snd_pcm_substream *substream, int cmd) 257 { 258 struct snd_pcm_runtime *runtime = substream->runtime; 259 struct loopback_pcm *dpcm = runtime->private_data; 260 struct loopback_cable *cable = dpcm->cable; 261 int err, stream = 1 << substream->stream; 262 263 switch (cmd) { 264 case SNDRV_PCM_TRIGGER_START: 265 err = loopback_check_format(cable, substream->stream); 266 if (err < 0) 267 return err; 268 dpcm->last_jiffies = jiffies; 269 dpcm->pcm_rate_shift = 0; 270 dpcm->last_drift = 0; 271 spin_lock(&cable->lock); 272 cable->running |= stream; 273 cable->pause &= ~stream; 274 loopback_timer_start(dpcm); 275 spin_unlock(&cable->lock); 276 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) 277 loopback_active_notify(dpcm); 278 break; 279 case SNDRV_PCM_TRIGGER_STOP: 280 spin_lock(&cable->lock); 281 cable->running &= ~stream; 282 cable->pause &= ~stream; 283 loopback_timer_stop(dpcm); 284 spin_unlock(&cable->lock); 285 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) 286 loopback_active_notify(dpcm); 287 break; 288 case SNDRV_PCM_TRIGGER_PAUSE_PUSH: 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 spin_lock(&cable->lock); 296 dpcm->last_jiffies = jiffies; 297 cable->pause &= ~stream; 298 loopback_timer_start(dpcm); 299 spin_unlock(&cable->lock); 300 break; 301 default: 302 return -EINVAL; 303 } 304 return 0; 305 } 306 307 static void params_change_substream(struct loopback_pcm *dpcm, 308 struct snd_pcm_runtime *runtime) 309 { 310 struct snd_pcm_runtime *dst_runtime; 311 312 if (dpcm == NULL || dpcm->substream == NULL) 313 return; 314 dst_runtime = dpcm->substream->runtime; 315 if (dst_runtime == NULL) 316 return; 317 dst_runtime->hw = dpcm->cable->hw; 318 } 319 320 static void params_change(struct snd_pcm_substream *substream) 321 { 322 struct snd_pcm_runtime *runtime = substream->runtime; 323 struct loopback_pcm *dpcm = runtime->private_data; 324 struct loopback_cable *cable = dpcm->cable; 325 326 cable->hw.formats = (1ULL << runtime->format); 327 cable->hw.rate_min = runtime->rate; 328 cable->hw.rate_max = runtime->rate; 329 cable->hw.channels_min = runtime->channels; 330 cable->hw.channels_max = runtime->channels; 331 params_change_substream(cable->streams[SNDRV_PCM_STREAM_PLAYBACK], 332 runtime); 333 params_change_substream(cable->streams[SNDRV_PCM_STREAM_CAPTURE], 334 runtime); 335 } 336 337 static int loopback_prepare(struct snd_pcm_substream *substream) 338 { 339 struct snd_pcm_runtime *runtime = substream->runtime; 340 struct loopback_pcm *dpcm = runtime->private_data; 341 struct loopback_cable *cable = dpcm->cable; 342 int bps, salign; 343 344 salign = (snd_pcm_format_width(runtime->format) * 345 runtime->channels) / 8; 346 bps = salign * runtime->rate; 347 if (bps <= 0 || salign <= 0) 348 return -EINVAL; 349 350 dpcm->buf_pos = 0; 351 dpcm->pcm_buffer_size = frames_to_bytes(runtime, runtime->buffer_size); 352 if (substream->stream == SNDRV_PCM_STREAM_CAPTURE) { 353 /* clear capture buffer */ 354 dpcm->silent_size = dpcm->pcm_buffer_size; 355 snd_pcm_format_set_silence(runtime->format, runtime->dma_area, 356 runtime->buffer_size * runtime->channels); 357 } 358 359 dpcm->irq_pos = 0; 360 dpcm->period_update_pending = 0; 361 dpcm->pcm_bps = bps; 362 dpcm->pcm_salign = salign; 363 dpcm->pcm_period_size = frames_to_bytes(runtime, runtime->period_size); 364 365 mutex_lock(&dpcm->loopback->cable_lock); 366 if (!(cable->valid & ~(1 << substream->stream)) || 367 (get_setup(dpcm)->notify && 368 substream->stream == SNDRV_PCM_STREAM_PLAYBACK)) 369 params_change(substream); 370 cable->valid |= 1 << substream->stream; 371 mutex_unlock(&dpcm->loopback->cable_lock); 372 373 return 0; 374 } 375 376 static void clear_capture_buf(struct loopback_pcm *dpcm, unsigned int bytes) 377 { 378 struct snd_pcm_runtime *runtime = dpcm->substream->runtime; 379 char *dst = runtime->dma_area; 380 unsigned int dst_off = dpcm->buf_pos; 381 382 if (dpcm->silent_size >= dpcm->pcm_buffer_size) 383 return; 384 if (dpcm->silent_size + bytes > dpcm->pcm_buffer_size) 385 bytes = dpcm->pcm_buffer_size - dpcm->silent_size; 386 387 for (;;) { 388 unsigned int size = bytes; 389 if (dst_off + size > dpcm->pcm_buffer_size) 390 size = dpcm->pcm_buffer_size - dst_off; 391 snd_pcm_format_set_silence(runtime->format, dst + dst_off, 392 bytes_to_frames(runtime, size) * 393 runtime->channels); 394 dpcm->silent_size += size; 395 bytes -= size; 396 if (!bytes) 397 break; 398 dst_off = 0; 399 } 400 } 401 402 static void copy_play_buf(struct loopback_pcm *play, 403 struct loopback_pcm *capt, 404 unsigned int bytes) 405 { 406 struct snd_pcm_runtime *runtime = play->substream->runtime; 407 char *src = runtime->dma_area; 408 char *dst = capt->substream->runtime->dma_area; 409 unsigned int src_off = play->buf_pos; 410 unsigned int dst_off = capt->buf_pos; 411 unsigned int clear_bytes = 0; 412 413 /* check if playback is draining, trim the capture copy size 414 * when our pointer is at the end of playback ring buffer */ 415 if (runtime->status->state == SNDRV_PCM_STATE_DRAINING && 416 snd_pcm_playback_hw_avail(runtime) < runtime->buffer_size) { 417 snd_pcm_uframes_t appl_ptr, appl_ptr1, diff; 418 appl_ptr = appl_ptr1 = runtime->control->appl_ptr; 419 appl_ptr1 -= appl_ptr1 % runtime->buffer_size; 420 appl_ptr1 += play->buf_pos / play->pcm_salign; 421 if (appl_ptr < appl_ptr1) 422 appl_ptr1 -= runtime->buffer_size; 423 diff = (appl_ptr - appl_ptr1) * play->pcm_salign; 424 if (diff < bytes) { 425 clear_bytes = bytes - diff; 426 bytes = diff; 427 } 428 } 429 430 for (;;) { 431 unsigned int size = bytes; 432 if (src_off + size > play->pcm_buffer_size) 433 size = play->pcm_buffer_size - src_off; 434 if (dst_off + size > capt->pcm_buffer_size) 435 size = capt->pcm_buffer_size - dst_off; 436 memcpy(dst + dst_off, src + src_off, size); 437 capt->silent_size = 0; 438 bytes -= size; 439 if (!bytes) 440 break; 441 src_off = (src_off + size) % play->pcm_buffer_size; 442 dst_off = (dst_off + size) % capt->pcm_buffer_size; 443 } 444 445 if (clear_bytes > 0) { 446 clear_capture_buf(capt, clear_bytes); 447 capt->silent_size = 0; 448 } 449 } 450 451 static inline unsigned int bytepos_delta(struct loopback_pcm *dpcm, 452 unsigned int jiffies_delta) 453 { 454 unsigned long last_pos; 455 unsigned int delta; 456 457 last_pos = byte_pos(dpcm, dpcm->irq_pos); 458 dpcm->irq_pos += jiffies_delta * dpcm->pcm_bps; 459 delta = byte_pos(dpcm, dpcm->irq_pos) - last_pos; 460 if (delta >= dpcm->last_drift) 461 delta -= dpcm->last_drift; 462 dpcm->last_drift = 0; 463 if (dpcm->irq_pos >= dpcm->period_size_frac) { 464 dpcm->irq_pos %= dpcm->period_size_frac; 465 dpcm->period_update_pending = 1; 466 } 467 return delta; 468 } 469 470 static inline void bytepos_finish(struct loopback_pcm *dpcm, 471 unsigned int delta) 472 { 473 dpcm->buf_pos += delta; 474 dpcm->buf_pos %= dpcm->pcm_buffer_size; 475 } 476 477 /* call in cable->lock */ 478 static unsigned int loopback_pos_update(struct loopback_cable *cable) 479 { 480 struct loopback_pcm *dpcm_play = 481 cable->streams[SNDRV_PCM_STREAM_PLAYBACK]; 482 struct loopback_pcm *dpcm_capt = 483 cable->streams[SNDRV_PCM_STREAM_CAPTURE]; 484 unsigned long delta_play = 0, delta_capt = 0; 485 unsigned int running, count1, count2; 486 487 running = cable->running ^ cable->pause; 488 if (running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) { 489 delta_play = jiffies - dpcm_play->last_jiffies; 490 dpcm_play->last_jiffies += delta_play; 491 } 492 493 if (running & (1 << SNDRV_PCM_STREAM_CAPTURE)) { 494 delta_capt = jiffies - dpcm_capt->last_jiffies; 495 dpcm_capt->last_jiffies += delta_capt; 496 } 497 498 if (delta_play == 0 && delta_capt == 0) 499 goto unlock; 500 501 if (delta_play > delta_capt) { 502 count1 = bytepos_delta(dpcm_play, delta_play - delta_capt); 503 bytepos_finish(dpcm_play, count1); 504 delta_play = delta_capt; 505 } else if (delta_play < delta_capt) { 506 count1 = bytepos_delta(dpcm_capt, delta_capt - delta_play); 507 clear_capture_buf(dpcm_capt, count1); 508 bytepos_finish(dpcm_capt, count1); 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 count1 = bytepos_delta(dpcm_play, delta_play); 517 count2 = bytepos_delta(dpcm_capt, delta_capt); 518 if (count1 < count2) { 519 dpcm_capt->last_drift = count2 - count1; 520 count1 = count2; 521 } else if (count1 > count2) { 522 dpcm_play->last_drift = count1 - count2; 523 } 524 copy_play_buf(dpcm_play, dpcm_capt, count1); 525 bytepos_finish(dpcm_play, count1); 526 bytepos_finish(dpcm_capt, count1); 527 unlock: 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 long flags; 535 536 spin_lock_irqsave(&dpcm->cable->lock, flags); 537 if (loopback_pos_update(dpcm->cable) & (1 << dpcm->substream->stream)) { 538 loopback_timer_start(dpcm); 539 if (dpcm->period_update_pending) { 540 dpcm->period_update_pending = 0; 541 spin_unlock_irqrestore(&dpcm->cable->lock, flags); 542 /* need to unlock before calling below */ 543 snd_pcm_period_elapsed(dpcm->substream); 544 return; 545 } 546 } 547 spin_unlock_irqrestore(&dpcm->cable->lock, flags); 548 } 549 550 static snd_pcm_uframes_t loopback_pointer(struct snd_pcm_substream *substream) 551 { 552 struct snd_pcm_runtime *runtime = substream->runtime; 553 struct loopback_pcm *dpcm = runtime->private_data; 554 snd_pcm_uframes_t pos; 555 556 spin_lock(&dpcm->cable->lock); 557 loopback_pos_update(dpcm->cable); 558 pos = dpcm->buf_pos; 559 spin_unlock(&dpcm->cable->lock); 560 return bytes_to_frames(runtime, pos); 561 } 562 563 static struct snd_pcm_hardware loopback_pcm_hardware = 564 { 565 .info = (SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_MMAP | 566 SNDRV_PCM_INFO_MMAP_VALID | SNDRV_PCM_INFO_PAUSE), 567 .formats = (SNDRV_PCM_FMTBIT_S16_LE | SNDRV_PCM_FMTBIT_S16_BE | 568 SNDRV_PCM_FMTBIT_S32_LE | SNDRV_PCM_FMTBIT_S32_BE | 569 SNDRV_PCM_FMTBIT_FLOAT_LE | SNDRV_PCM_FMTBIT_FLOAT_BE), 570 .rates = SNDRV_PCM_RATE_CONTINUOUS | SNDRV_PCM_RATE_8000_192000, 571 .rate_min = 8000, 572 .rate_max = 192000, 573 .channels_min = 1, 574 .channels_max = 32, 575 .buffer_bytes_max = 2 * 1024 * 1024, 576 .period_bytes_min = 64, 577 /* note check overflow in frac_pos() using pcm_rate_shift before 578 changing period_bytes_max value */ 579 .period_bytes_max = 1024 * 1024, 580 .periods_min = 1, 581 .periods_max = 1024, 582 .fifo_size = 0, 583 }; 584 585 static void loopback_runtime_free(struct snd_pcm_runtime *runtime) 586 { 587 struct loopback_pcm *dpcm = runtime->private_data; 588 kfree(dpcm); 589 } 590 591 static int loopback_hw_params(struct snd_pcm_substream *substream, 592 struct snd_pcm_hw_params *params) 593 { 594 return snd_pcm_lib_alloc_vmalloc_buffer(substream, 595 params_buffer_bytes(params)); 596 } 597 598 static int loopback_hw_free(struct snd_pcm_substream *substream) 599 { 600 struct snd_pcm_runtime *runtime = substream->runtime; 601 struct loopback_pcm *dpcm = runtime->private_data; 602 struct loopback_cable *cable = dpcm->cable; 603 604 mutex_lock(&dpcm->loopback->cable_lock); 605 cable->valid &= ~(1 << substream->stream); 606 mutex_unlock(&dpcm->loopback->cable_lock); 607 return snd_pcm_lib_free_vmalloc_buffer(substream); 608 } 609 610 static unsigned int get_cable_index(struct snd_pcm_substream *substream) 611 { 612 if (!substream->pcm->device) 613 return substream->stream; 614 else 615 return !substream->stream; 616 } 617 618 static int rule_format(struct snd_pcm_hw_params *params, 619 struct snd_pcm_hw_rule *rule) 620 { 621 622 struct snd_pcm_hardware *hw = rule->private; 623 struct snd_mask *maskp = hw_param_mask(params, rule->var); 624 625 maskp->bits[0] &= (u_int32_t)hw->formats; 626 maskp->bits[1] &= (u_int32_t)(hw->formats >> 32); 627 memset(maskp->bits + 2, 0, (SNDRV_MASK_MAX-64) / 8); /* clear rest */ 628 if (! maskp->bits[0] && ! maskp->bits[1]) 629 return -EINVAL; 630 return 0; 631 } 632 633 static int rule_rate(struct snd_pcm_hw_params *params, 634 struct snd_pcm_hw_rule *rule) 635 { 636 struct snd_pcm_hardware *hw = rule->private; 637 struct snd_interval t; 638 639 t.min = hw->rate_min; 640 t.max = hw->rate_max; 641 t.openmin = t.openmax = 0; 642 t.integer = 0; 643 return snd_interval_refine(hw_param_interval(params, rule->var), &t); 644 } 645 646 static int rule_channels(struct snd_pcm_hw_params *params, 647 struct snd_pcm_hw_rule *rule) 648 { 649 struct snd_pcm_hardware *hw = rule->private; 650 struct snd_interval t; 651 652 t.min = hw->channels_min; 653 t.max = hw->channels_max; 654 t.openmin = t.openmax = 0; 655 t.integer = 0; 656 return snd_interval_refine(hw_param_interval(params, rule->var), &t); 657 } 658 659 static int loopback_open(struct snd_pcm_substream *substream) 660 { 661 struct snd_pcm_runtime *runtime = substream->runtime; 662 struct loopback *loopback = substream->private_data; 663 struct loopback_pcm *dpcm; 664 struct loopback_cable *cable; 665 int err = 0; 666 int dev = get_cable_index(substream); 667 668 mutex_lock(&loopback->cable_lock); 669 dpcm = kzalloc(sizeof(*dpcm), GFP_KERNEL); 670 if (!dpcm) { 671 err = -ENOMEM; 672 goto unlock; 673 } 674 dpcm->loopback = loopback; 675 dpcm->substream = substream; 676 setup_timer(&dpcm->timer, loopback_timer_function, 677 (unsigned long)dpcm); 678 679 cable = loopback->cables[substream->number][dev]; 680 if (!cable) { 681 cable = kzalloc(sizeof(*cable), GFP_KERNEL); 682 if (!cable) { 683 kfree(dpcm); 684 err = -ENOMEM; 685 goto unlock; 686 } 687 spin_lock_init(&cable->lock); 688 cable->hw = loopback_pcm_hardware; 689 loopback->cables[substream->number][dev] = cable; 690 } 691 dpcm->cable = cable; 692 cable->streams[substream->stream] = dpcm; 693 694 snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS); 695 696 /* use dynamic rules based on actual runtime->hw values */ 697 /* note that the default rules created in the PCM midlevel code */ 698 /* are cached -> they do not reflect the actual state */ 699 err = snd_pcm_hw_rule_add(runtime, 0, 700 SNDRV_PCM_HW_PARAM_FORMAT, 701 rule_format, &runtime->hw, 702 SNDRV_PCM_HW_PARAM_FORMAT, -1); 703 if (err < 0) 704 goto unlock; 705 err = snd_pcm_hw_rule_add(runtime, 0, 706 SNDRV_PCM_HW_PARAM_RATE, 707 rule_rate, &runtime->hw, 708 SNDRV_PCM_HW_PARAM_RATE, -1); 709 if (err < 0) 710 goto unlock; 711 err = snd_pcm_hw_rule_add(runtime, 0, 712 SNDRV_PCM_HW_PARAM_CHANNELS, 713 rule_channels, &runtime->hw, 714 SNDRV_PCM_HW_PARAM_CHANNELS, -1); 715 if (err < 0) 716 goto unlock; 717 718 runtime->private_data = dpcm; 719 runtime->private_free = loopback_runtime_free; 720 if (get_notify(dpcm)) 721 runtime->hw = loopback_pcm_hardware; 722 else 723 runtime->hw = cable->hw; 724 unlock: 725 mutex_unlock(&loopback->cable_lock); 726 return err; 727 } 728 729 static int loopback_close(struct snd_pcm_substream *substream) 730 { 731 struct loopback *loopback = substream->private_data; 732 struct loopback_pcm *dpcm = substream->runtime->private_data; 733 struct loopback_cable *cable; 734 int dev = get_cable_index(substream); 735 736 loopback_timer_stop(dpcm); 737 mutex_lock(&loopback->cable_lock); 738 cable = loopback->cables[substream->number][dev]; 739 if (cable->streams[!substream->stream]) { 740 /* other stream is still alive */ 741 cable->streams[substream->stream] = NULL; 742 } else { 743 /* free the cable */ 744 loopback->cables[substream->number][dev] = NULL; 745 kfree(cable); 746 } 747 mutex_unlock(&loopback->cable_lock); 748 return 0; 749 } 750 751 static struct snd_pcm_ops loopback_playback_ops = { 752 .open = loopback_open, 753 .close = loopback_close, 754 .ioctl = snd_pcm_lib_ioctl, 755 .hw_params = loopback_hw_params, 756 .hw_free = loopback_hw_free, 757 .prepare = loopback_prepare, 758 .trigger = loopback_trigger, 759 .pointer = loopback_pointer, 760 .page = snd_pcm_lib_get_vmalloc_page, 761 .mmap = snd_pcm_lib_mmap_vmalloc, 762 }; 763 764 static struct snd_pcm_ops loopback_capture_ops = { 765 .open = loopback_open, 766 .close = loopback_close, 767 .ioctl = snd_pcm_lib_ioctl, 768 .hw_params = loopback_hw_params, 769 .hw_free = loopback_hw_free, 770 .prepare = loopback_prepare, 771 .trigger = loopback_trigger, 772 .pointer = loopback_pointer, 773 .page = snd_pcm_lib_get_vmalloc_page, 774 .mmap = snd_pcm_lib_mmap_vmalloc, 775 }; 776 777 static int loopback_pcm_new(struct loopback *loopback, 778 int device, int substreams) 779 { 780 struct snd_pcm *pcm; 781 int err; 782 783 err = snd_pcm_new(loopback->card, "Loopback PCM", device, 784 substreams, substreams, &pcm); 785 if (err < 0) 786 return err; 787 snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &loopback_playback_ops); 788 snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &loopback_capture_ops); 789 790 pcm->private_data = loopback; 791 pcm->info_flags = 0; 792 strcpy(pcm->name, "Loopback PCM"); 793 794 loopback->pcm[device] = pcm; 795 return 0; 796 } 797 798 static int loopback_rate_shift_info(struct snd_kcontrol *kcontrol, 799 struct snd_ctl_elem_info *uinfo) 800 { 801 uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER; 802 uinfo->count = 1; 803 uinfo->value.integer.min = 80000; 804 uinfo->value.integer.max = 120000; 805 uinfo->value.integer.step = 1; 806 return 0; 807 } 808 809 static int loopback_rate_shift_get(struct snd_kcontrol *kcontrol, 810 struct snd_ctl_elem_value *ucontrol) 811 { 812 struct loopback *loopback = snd_kcontrol_chip(kcontrol); 813 814 ucontrol->value.integer.value[0] = 815 loopback->setup[kcontrol->id.subdevice] 816 [kcontrol->id.device].rate_shift; 817 return 0; 818 } 819 820 static int loopback_rate_shift_put(struct snd_kcontrol *kcontrol, 821 struct snd_ctl_elem_value *ucontrol) 822 { 823 struct loopback *loopback = snd_kcontrol_chip(kcontrol); 824 unsigned int val; 825 int change = 0; 826 827 val = ucontrol->value.integer.value[0]; 828 if (val < 80000) 829 val = 80000; 830 if (val > 120000) 831 val = 120000; 832 mutex_lock(&loopback->cable_lock); 833 if (val != loopback->setup[kcontrol->id.subdevice] 834 [kcontrol->id.device].rate_shift) { 835 loopback->setup[kcontrol->id.subdevice] 836 [kcontrol->id.device].rate_shift = val; 837 change = 1; 838 } 839 mutex_unlock(&loopback->cable_lock); 840 return change; 841 } 842 843 static int loopback_notify_get(struct snd_kcontrol *kcontrol, 844 struct snd_ctl_elem_value *ucontrol) 845 { 846 struct loopback *loopback = snd_kcontrol_chip(kcontrol); 847 848 ucontrol->value.integer.value[0] = 849 loopback->setup[kcontrol->id.subdevice] 850 [kcontrol->id.device].notify; 851 return 0; 852 } 853 854 static int loopback_notify_put(struct snd_kcontrol *kcontrol, 855 struct snd_ctl_elem_value *ucontrol) 856 { 857 struct loopback *loopback = snd_kcontrol_chip(kcontrol); 858 unsigned int val; 859 int change = 0; 860 861 val = ucontrol->value.integer.value[0] ? 1 : 0; 862 if (val != loopback->setup[kcontrol->id.subdevice] 863 [kcontrol->id.device].notify) { 864 loopback->setup[kcontrol->id.subdevice] 865 [kcontrol->id.device].notify = val; 866 change = 1; 867 } 868 return change; 869 } 870 871 static int loopback_active_get(struct snd_kcontrol *kcontrol, 872 struct snd_ctl_elem_value *ucontrol) 873 { 874 struct loopback *loopback = snd_kcontrol_chip(kcontrol); 875 struct loopback_cable *cable = loopback->cables 876 [kcontrol->id.subdevice][kcontrol->id.device ^ 1]; 877 unsigned int val = 0; 878 879 if (cable != NULL) 880 val = (cable->running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) ? 881 1 : 0; 882 ucontrol->value.integer.value[0] = val; 883 return 0; 884 } 885 886 static int loopback_format_info(struct snd_kcontrol *kcontrol, 887 struct snd_ctl_elem_info *uinfo) 888 { 889 uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER; 890 uinfo->count = 1; 891 uinfo->value.integer.min = 0; 892 uinfo->value.integer.max = SNDRV_PCM_FORMAT_LAST; 893 uinfo->value.integer.step = 1; 894 return 0; 895 } 896 897 static int loopback_format_get(struct snd_kcontrol *kcontrol, 898 struct snd_ctl_elem_value *ucontrol) 899 { 900 struct loopback *loopback = snd_kcontrol_chip(kcontrol); 901 902 ucontrol->value.integer.value[0] = 903 loopback->setup[kcontrol->id.subdevice] 904 [kcontrol->id.device].format; 905 return 0; 906 } 907 908 static int loopback_rate_info(struct snd_kcontrol *kcontrol, 909 struct snd_ctl_elem_info *uinfo) 910 { 911 uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER; 912 uinfo->count = 1; 913 uinfo->value.integer.min = 0; 914 uinfo->value.integer.max = 192000; 915 uinfo->value.integer.step = 1; 916 return 0; 917 } 918 919 static int loopback_rate_get(struct snd_kcontrol *kcontrol, 920 struct snd_ctl_elem_value *ucontrol) 921 { 922 struct loopback *loopback = snd_kcontrol_chip(kcontrol); 923 924 ucontrol->value.integer.value[0] = 925 loopback->setup[kcontrol->id.subdevice] 926 [kcontrol->id.device].rate; 927 return 0; 928 } 929 930 static int loopback_channels_info(struct snd_kcontrol *kcontrol, 931 struct snd_ctl_elem_info *uinfo) 932 { 933 uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER; 934 uinfo->count = 1; 935 uinfo->value.integer.min = 1; 936 uinfo->value.integer.max = 1024; 937 uinfo->value.integer.step = 1; 938 return 0; 939 } 940 941 static int loopback_channels_get(struct snd_kcontrol *kcontrol, 942 struct snd_ctl_elem_value *ucontrol) 943 { 944 struct loopback *loopback = snd_kcontrol_chip(kcontrol); 945 946 ucontrol->value.integer.value[0] = 947 loopback->setup[kcontrol->id.subdevice] 948 [kcontrol->id.device].channels; 949 return 0; 950 } 951 952 static struct snd_kcontrol_new loopback_controls[] = { 953 { 954 .iface = SNDRV_CTL_ELEM_IFACE_PCM, 955 .name = "PCM Rate Shift 100000", 956 .info = loopback_rate_shift_info, 957 .get = loopback_rate_shift_get, 958 .put = loopback_rate_shift_put, 959 }, 960 { 961 .iface = SNDRV_CTL_ELEM_IFACE_PCM, 962 .name = "PCM Notify", 963 .info = snd_ctl_boolean_mono_info, 964 .get = loopback_notify_get, 965 .put = loopback_notify_put, 966 }, 967 #define ACTIVE_IDX 2 968 { 969 .access = SNDRV_CTL_ELEM_ACCESS_READ, 970 .iface = SNDRV_CTL_ELEM_IFACE_PCM, 971 .name = "PCM Slave Active", 972 .info = snd_ctl_boolean_mono_info, 973 .get = loopback_active_get, 974 }, 975 #define FORMAT_IDX 3 976 { 977 .access = SNDRV_CTL_ELEM_ACCESS_READ, 978 .iface = SNDRV_CTL_ELEM_IFACE_PCM, 979 .name = "PCM Slave Format", 980 .info = loopback_format_info, 981 .get = loopback_format_get 982 }, 983 #define RATE_IDX 4 984 { 985 .access = SNDRV_CTL_ELEM_ACCESS_READ, 986 .iface = SNDRV_CTL_ELEM_IFACE_PCM, 987 .name = "PCM Slave Rate", 988 .info = loopback_rate_info, 989 .get = loopback_rate_get 990 }, 991 #define CHANNELS_IDX 5 992 { 993 .access = SNDRV_CTL_ELEM_ACCESS_READ, 994 .iface = SNDRV_CTL_ELEM_IFACE_PCM, 995 .name = "PCM Slave Channels", 996 .info = loopback_channels_info, 997 .get = loopback_channels_get 998 } 999 }; 1000 1001 static int loopback_mixer_new(struct loopback *loopback, int notify) 1002 { 1003 struct snd_card *card = loopback->card; 1004 struct snd_pcm *pcm; 1005 struct snd_kcontrol *kctl; 1006 struct loopback_setup *setup; 1007 int err, dev, substr, substr_count, idx; 1008 1009 strcpy(card->mixername, "Loopback Mixer"); 1010 for (dev = 0; dev < 2; dev++) { 1011 pcm = loopback->pcm[dev]; 1012 substr_count = 1013 pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream_count; 1014 for (substr = 0; substr < substr_count; substr++) { 1015 setup = &loopback->setup[substr][dev]; 1016 setup->notify = notify; 1017 setup->rate_shift = NO_PITCH; 1018 setup->format = SNDRV_PCM_FORMAT_S16_LE; 1019 setup->rate = 48000; 1020 setup->channels = 2; 1021 for (idx = 0; idx < ARRAY_SIZE(loopback_controls); 1022 idx++) { 1023 kctl = snd_ctl_new1(&loopback_controls[idx], 1024 loopback); 1025 if (!kctl) 1026 return -ENOMEM; 1027 kctl->id.device = dev; 1028 kctl->id.subdevice = substr; 1029 switch (idx) { 1030 case ACTIVE_IDX: 1031 setup->active_id = kctl->id; 1032 break; 1033 case FORMAT_IDX: 1034 setup->format_id = kctl->id; 1035 break; 1036 case RATE_IDX: 1037 setup->rate_id = kctl->id; 1038 break; 1039 case CHANNELS_IDX: 1040 setup->channels_id = kctl->id; 1041 break; 1042 default: 1043 break; 1044 } 1045 err = snd_ctl_add(card, kctl); 1046 if (err < 0) 1047 return err; 1048 } 1049 } 1050 } 1051 return 0; 1052 } 1053 1054 #ifdef CONFIG_PROC_FS 1055 1056 static void print_dpcm_info(struct snd_info_buffer *buffer, 1057 struct loopback_pcm *dpcm, 1058 const char *id) 1059 { 1060 snd_iprintf(buffer, " %s\n", id); 1061 if (dpcm == NULL) { 1062 snd_iprintf(buffer, " inactive\n"); 1063 return; 1064 } 1065 snd_iprintf(buffer, " buffer_size:\t%u\n", dpcm->pcm_buffer_size); 1066 snd_iprintf(buffer, " buffer_pos:\t\t%u\n", dpcm->buf_pos); 1067 snd_iprintf(buffer, " silent_size:\t%u\n", dpcm->silent_size); 1068 snd_iprintf(buffer, " period_size:\t%u\n", dpcm->pcm_period_size); 1069 snd_iprintf(buffer, " bytes_per_sec:\t%u\n", dpcm->pcm_bps); 1070 snd_iprintf(buffer, " sample_align:\t%u\n", dpcm->pcm_salign); 1071 snd_iprintf(buffer, " rate_shift:\t\t%u\n", dpcm->pcm_rate_shift); 1072 snd_iprintf(buffer, " update_pending:\t%u\n", 1073 dpcm->period_update_pending); 1074 snd_iprintf(buffer, " irq_pos:\t\t%u\n", dpcm->irq_pos); 1075 snd_iprintf(buffer, " period_frac:\t%u\n", dpcm->period_size_frac); 1076 snd_iprintf(buffer, " last_jiffies:\t%lu (%lu)\n", 1077 dpcm->last_jiffies, jiffies); 1078 snd_iprintf(buffer, " timer_expires:\t%lu\n", dpcm->timer.expires); 1079 } 1080 1081 static void print_substream_info(struct snd_info_buffer *buffer, 1082 struct loopback *loopback, 1083 int sub, 1084 int num) 1085 { 1086 struct loopback_cable *cable = loopback->cables[sub][num]; 1087 1088 snd_iprintf(buffer, "Cable %i substream %i:\n", num, sub); 1089 if (cable == NULL) { 1090 snd_iprintf(buffer, " inactive\n"); 1091 return; 1092 } 1093 snd_iprintf(buffer, " valid: %u\n", cable->valid); 1094 snd_iprintf(buffer, " running: %u\n", cable->running); 1095 snd_iprintf(buffer, " pause: %u\n", cable->pause); 1096 print_dpcm_info(buffer, cable->streams[0], "Playback"); 1097 print_dpcm_info(buffer, cable->streams[1], "Capture"); 1098 } 1099 1100 static void print_cable_info(struct snd_info_entry *entry, 1101 struct snd_info_buffer *buffer) 1102 { 1103 struct loopback *loopback = entry->private_data; 1104 int sub, num; 1105 1106 mutex_lock(&loopback->cable_lock); 1107 num = entry->name[strlen(entry->name)-1]; 1108 num = num == '0' ? 0 : 1; 1109 for (sub = 0; sub < MAX_PCM_SUBSTREAMS; sub++) 1110 print_substream_info(buffer, loopback, sub, num); 1111 mutex_unlock(&loopback->cable_lock); 1112 } 1113 1114 static int loopback_proc_new(struct loopback *loopback, int cidx) 1115 { 1116 char name[32]; 1117 struct snd_info_entry *entry; 1118 int err; 1119 1120 snprintf(name, sizeof(name), "cable#%d", cidx); 1121 err = snd_card_proc_new(loopback->card, name, &entry); 1122 if (err < 0) 1123 return err; 1124 1125 snd_info_set_text_ops(entry, loopback, print_cable_info); 1126 return 0; 1127 } 1128 1129 #else /* !CONFIG_PROC_FS */ 1130 1131 #define loopback_proc_new(loopback, cidx) do { } while (0) 1132 1133 #endif 1134 1135 static int loopback_probe(struct platform_device *devptr) 1136 { 1137 struct snd_card *card; 1138 struct loopback *loopback; 1139 int dev = devptr->id; 1140 int err; 1141 1142 err = snd_card_create(index[dev], id[dev], THIS_MODULE, 1143 sizeof(struct loopback), &card); 1144 if (err < 0) 1145 return err; 1146 loopback = card->private_data; 1147 1148 if (pcm_substreams[dev] < 1) 1149 pcm_substreams[dev] = 1; 1150 if (pcm_substreams[dev] > MAX_PCM_SUBSTREAMS) 1151 pcm_substreams[dev] = MAX_PCM_SUBSTREAMS; 1152 1153 loopback->card = card; 1154 mutex_init(&loopback->cable_lock); 1155 1156 err = loopback_pcm_new(loopback, 0, pcm_substreams[dev]); 1157 if (err < 0) 1158 goto __nodev; 1159 err = loopback_pcm_new(loopback, 1, pcm_substreams[dev]); 1160 if (err < 0) 1161 goto __nodev; 1162 err = loopback_mixer_new(loopback, pcm_notify[dev] ? 1 : 0); 1163 if (err < 0) 1164 goto __nodev; 1165 loopback_proc_new(loopback, 0); 1166 loopback_proc_new(loopback, 1); 1167 strcpy(card->driver, "Loopback"); 1168 strcpy(card->shortname, "Loopback"); 1169 sprintf(card->longname, "Loopback %i", dev + 1); 1170 err = snd_card_register(card); 1171 if (!err) { 1172 platform_set_drvdata(devptr, card); 1173 return 0; 1174 } 1175 __nodev: 1176 snd_card_free(card); 1177 return err; 1178 } 1179 1180 static int loopback_remove(struct platform_device *devptr) 1181 { 1182 snd_card_free(platform_get_drvdata(devptr)); 1183 platform_set_drvdata(devptr, NULL); 1184 return 0; 1185 } 1186 1187 #ifdef CONFIG_PM_SLEEP 1188 static int loopback_suspend(struct device *pdev) 1189 { 1190 struct snd_card *card = dev_get_drvdata(pdev); 1191 struct loopback *loopback = card->private_data; 1192 1193 snd_power_change_state(card, SNDRV_CTL_POWER_D3hot); 1194 1195 snd_pcm_suspend_all(loopback->pcm[0]); 1196 snd_pcm_suspend_all(loopback->pcm[1]); 1197 return 0; 1198 } 1199 1200 static int loopback_resume(struct device *pdev) 1201 { 1202 struct snd_card *card = dev_get_drvdata(pdev); 1203 1204 snd_power_change_state(card, SNDRV_CTL_POWER_D0); 1205 return 0; 1206 } 1207 1208 static SIMPLE_DEV_PM_OPS(loopback_pm, loopback_suspend, loopback_resume); 1209 #define LOOPBACK_PM_OPS &loopback_pm 1210 #else 1211 #define LOOPBACK_PM_OPS NULL 1212 #endif 1213 1214 #define SND_LOOPBACK_DRIVER "snd_aloop" 1215 1216 static struct platform_driver loopback_driver = { 1217 .probe = loopback_probe, 1218 .remove = loopback_remove, 1219 .driver = { 1220 .name = SND_LOOPBACK_DRIVER, 1221 .owner = THIS_MODULE, 1222 .pm = LOOPBACK_PM_OPS, 1223 }, 1224 }; 1225 1226 static 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 1235 static 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 1270 static void __exit alsa_card_loopback_exit(void) 1271 { 1272 loopback_unregister_all(); 1273 } 1274 1275 module_init(alsa_card_loopback_init) 1276 module_exit(alsa_card_loopback_exit) 1277