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 spinlock_t timer_lock; 124 }; 125 126 static struct platform_device *devices[SNDRV_CARDS]; 127 128 static inline unsigned int byte_pos(struct loopback_pcm *dpcm, unsigned int x) 129 { 130 if (dpcm->pcm_rate_shift == NO_PITCH) { 131 x /= HZ; 132 } else { 133 x = div_u64(NO_PITCH * (unsigned long long)x, 134 HZ * (unsigned long long)dpcm->pcm_rate_shift); 135 } 136 return x - (x % dpcm->pcm_salign); 137 } 138 139 static inline unsigned int frac_pos(struct loopback_pcm *dpcm, unsigned int x) 140 { 141 if (dpcm->pcm_rate_shift == NO_PITCH) { /* no pitch */ 142 return x * HZ; 143 } else { 144 x = div_u64(dpcm->pcm_rate_shift * (unsigned long long)x * HZ, 145 NO_PITCH); 146 } 147 return x; 148 } 149 150 static inline struct loopback_setup *get_setup(struct loopback_pcm *dpcm) 151 { 152 int device = dpcm->substream->pstr->pcm->device; 153 154 if (dpcm->substream->stream == SNDRV_PCM_STREAM_PLAYBACK) 155 device ^= 1; 156 return &dpcm->loopback->setup[dpcm->substream->number][device]; 157 } 158 159 static inline unsigned int get_notify(struct loopback_pcm *dpcm) 160 { 161 return get_setup(dpcm)->notify; 162 } 163 164 static inline unsigned int get_rate_shift(struct loopback_pcm *dpcm) 165 { 166 return get_setup(dpcm)->rate_shift; 167 } 168 169 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 spin_lock(&dpcm->timer_lock); 175 if (rate_shift != dpcm->pcm_rate_shift) { 176 dpcm->pcm_rate_shift = rate_shift; 177 dpcm->period_size_frac = frac_pos(dpcm, dpcm->pcm_period_size); 178 } 179 if (dpcm->period_size_frac <= dpcm->irq_pos) { 180 dpcm->irq_pos %= dpcm->period_size_frac; 181 dpcm->period_update_pending = 1; 182 } 183 tick = dpcm->period_size_frac - dpcm->irq_pos; 184 tick = (tick + dpcm->pcm_bps - 1) / dpcm->pcm_bps; 185 dpcm->timer.expires = jiffies + tick; 186 add_timer(&dpcm->timer); 187 spin_unlock(&dpcm->timer_lock); 188 } 189 190 static inline void loopback_timer_stop(struct loopback_pcm *dpcm) 191 { 192 spin_lock(&dpcm->timer_lock); 193 del_timer(&dpcm->timer); 194 dpcm->timer.expires = 0; 195 spin_unlock(&dpcm->timer_lock); 196 } 197 198 #define CABLE_VALID_PLAYBACK (1 << SNDRV_PCM_STREAM_PLAYBACK) 199 #define CABLE_VALID_CAPTURE (1 << SNDRV_PCM_STREAM_CAPTURE) 200 #define CABLE_VALID_BOTH (CABLE_VALID_PLAYBACK|CABLE_VALID_CAPTURE) 201 202 static int loopback_check_format(struct loopback_cable *cable, int stream) 203 { 204 struct snd_pcm_runtime *runtime, *cruntime; 205 struct loopback_setup *setup; 206 struct snd_card *card; 207 int check; 208 209 if (cable->valid != CABLE_VALID_BOTH) { 210 if (stream == SNDRV_PCM_STREAM_PLAYBACK) 211 goto __notify; 212 return 0; 213 } 214 runtime = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]-> 215 substream->runtime; 216 cruntime = cable->streams[SNDRV_PCM_STREAM_CAPTURE]-> 217 substream->runtime; 218 check = runtime->format != cruntime->format || 219 runtime->rate != cruntime->rate || 220 runtime->channels != cruntime->channels; 221 if (!check) 222 return 0; 223 if (stream == SNDRV_PCM_STREAM_CAPTURE) { 224 return -EIO; 225 } else { 226 snd_pcm_stop(cable->streams[SNDRV_PCM_STREAM_CAPTURE]-> 227 substream, SNDRV_PCM_STATE_DRAINING); 228 __notify: 229 runtime = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]-> 230 substream->runtime; 231 setup = get_setup(cable->streams[SNDRV_PCM_STREAM_PLAYBACK]); 232 card = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]->loopback->card; 233 if (setup->format != runtime->format) { 234 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE, 235 &setup->format_id); 236 setup->format = runtime->format; 237 } 238 if (setup->rate != runtime->rate) { 239 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE, 240 &setup->rate_id); 241 setup->rate = runtime->rate; 242 } 243 if (setup->channels != runtime->channels) { 244 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE, 245 &setup->channels_id); 246 setup->channels = runtime->channels; 247 } 248 } 249 return 0; 250 } 251 252 static void loopback_active_notify(struct loopback_pcm *dpcm) 253 { 254 snd_ctl_notify(dpcm->loopback->card, 255 SNDRV_CTL_EVENT_MASK_VALUE, 256 &get_setup(dpcm)->active_id); 257 } 258 259 static int loopback_trigger(struct snd_pcm_substream *substream, int cmd) 260 { 261 struct snd_pcm_runtime *runtime = substream->runtime; 262 struct loopback_pcm *dpcm = runtime->private_data; 263 struct loopback_cable *cable = dpcm->cable; 264 int err, stream = 1 << substream->stream; 265 266 switch (cmd) { 267 case SNDRV_PCM_TRIGGER_START: 268 err = loopback_check_format(cable, substream->stream); 269 if (err < 0) 270 return err; 271 dpcm->last_jiffies = jiffies; 272 dpcm->pcm_rate_shift = 0; 273 dpcm->last_drift = 0; 274 spin_lock(&cable->lock); 275 cable->running |= stream; 276 cable->pause &= ~stream; 277 spin_unlock(&cable->lock); 278 loopback_timer_start(dpcm); 279 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) 280 loopback_active_notify(dpcm); 281 break; 282 case SNDRV_PCM_TRIGGER_STOP: 283 spin_lock(&cable->lock); 284 cable->running &= ~stream; 285 cable->pause &= ~stream; 286 spin_unlock(&cable->lock); 287 loopback_timer_stop(dpcm); 288 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) 289 loopback_active_notify(dpcm); 290 break; 291 case SNDRV_PCM_TRIGGER_PAUSE_PUSH: 292 spin_lock(&cable->lock); 293 cable->pause |= stream; 294 spin_unlock(&cable->lock); 295 loopback_timer_stop(dpcm); 296 break; 297 case SNDRV_PCM_TRIGGER_PAUSE_RELEASE: 298 spin_lock(&cable->lock); 299 dpcm->last_jiffies = jiffies; 300 cable->pause &= ~stream; 301 spin_unlock(&cable->lock); 302 loopback_timer_start(dpcm); 303 break; 304 default: 305 return -EINVAL; 306 } 307 return 0; 308 } 309 310 static void params_change_substream(struct loopback_pcm *dpcm, 311 struct snd_pcm_runtime *runtime) 312 { 313 struct snd_pcm_runtime *dst_runtime; 314 315 if (dpcm == NULL || dpcm->substream == NULL) 316 return; 317 dst_runtime = dpcm->substream->runtime; 318 if (dst_runtime == NULL) 319 return; 320 dst_runtime->hw = dpcm->cable->hw; 321 } 322 323 static void params_change(struct snd_pcm_substream *substream) 324 { 325 struct snd_pcm_runtime *runtime = substream->runtime; 326 struct loopback_pcm *dpcm = runtime->private_data; 327 struct loopback_cable *cable = dpcm->cable; 328 329 cable->hw.formats = (1ULL << runtime->format); 330 cable->hw.rate_min = runtime->rate; 331 cable->hw.rate_max = runtime->rate; 332 cable->hw.channels_min = runtime->channels; 333 cable->hw.channels_max = runtime->channels; 334 params_change_substream(cable->streams[SNDRV_PCM_STREAM_PLAYBACK], 335 runtime); 336 params_change_substream(cable->streams[SNDRV_PCM_STREAM_CAPTURE], 337 runtime); 338 } 339 340 static int loopback_prepare(struct snd_pcm_substream *substream) 341 { 342 struct snd_pcm_runtime *runtime = substream->runtime; 343 struct loopback_pcm *dpcm = runtime->private_data; 344 struct loopback_cable *cable = dpcm->cable; 345 int bps, salign; 346 347 salign = (snd_pcm_format_width(runtime->format) * 348 runtime->channels) / 8; 349 bps = salign * runtime->rate; 350 if (bps <= 0 || salign <= 0) 351 return -EINVAL; 352 353 dpcm->buf_pos = 0; 354 dpcm->pcm_buffer_size = frames_to_bytes(runtime, runtime->buffer_size); 355 if (substream->stream == SNDRV_PCM_STREAM_CAPTURE) { 356 /* clear capture buffer */ 357 dpcm->silent_size = dpcm->pcm_buffer_size; 358 snd_pcm_format_set_silence(runtime->format, runtime->dma_area, 359 runtime->buffer_size * runtime->channels); 360 } 361 362 dpcm->irq_pos = 0; 363 dpcm->period_update_pending = 0; 364 dpcm->pcm_bps = bps; 365 dpcm->pcm_salign = salign; 366 dpcm->pcm_period_size = frames_to_bytes(runtime, runtime->period_size); 367 368 mutex_lock(&dpcm->loopback->cable_lock); 369 if (!(cable->valid & ~(1 << substream->stream)) || 370 (get_setup(dpcm)->notify && 371 substream->stream == SNDRV_PCM_STREAM_PLAYBACK)) 372 params_change(substream); 373 cable->valid |= 1 << substream->stream; 374 mutex_unlock(&dpcm->loopback->cable_lock); 375 376 return 0; 377 } 378 379 static void clear_capture_buf(struct loopback_pcm *dpcm, unsigned int bytes) 380 { 381 struct snd_pcm_runtime *runtime = dpcm->substream->runtime; 382 char *dst = runtime->dma_area; 383 unsigned int dst_off = dpcm->buf_pos; 384 385 if (dpcm->silent_size >= dpcm->pcm_buffer_size) 386 return; 387 if (dpcm->silent_size + bytes > dpcm->pcm_buffer_size) 388 bytes = dpcm->pcm_buffer_size - dpcm->silent_size; 389 390 for (;;) { 391 unsigned int size = bytes; 392 if (dst_off + size > dpcm->pcm_buffer_size) 393 size = dpcm->pcm_buffer_size - dst_off; 394 snd_pcm_format_set_silence(runtime->format, dst + dst_off, 395 bytes_to_frames(runtime, size) * 396 runtime->channels); 397 dpcm->silent_size += size; 398 bytes -= size; 399 if (!bytes) 400 break; 401 dst_off = 0; 402 } 403 } 404 405 static void copy_play_buf(struct loopback_pcm *play, 406 struct loopback_pcm *capt, 407 unsigned int bytes) 408 { 409 struct snd_pcm_runtime *runtime = play->substream->runtime; 410 char *src = runtime->dma_area; 411 char *dst = capt->substream->runtime->dma_area; 412 unsigned int src_off = play->buf_pos; 413 unsigned int dst_off = capt->buf_pos; 414 unsigned int clear_bytes = 0; 415 416 /* check if playback is draining, trim the capture copy size 417 * when our pointer is at the end of playback ring buffer */ 418 if (runtime->status->state == SNDRV_PCM_STATE_DRAINING && 419 snd_pcm_playback_hw_avail(runtime) < runtime->buffer_size) { 420 snd_pcm_uframes_t appl_ptr, appl_ptr1, diff; 421 appl_ptr = appl_ptr1 = runtime->control->appl_ptr; 422 appl_ptr1 -= appl_ptr1 % runtime->buffer_size; 423 appl_ptr1 += play->buf_pos / play->pcm_salign; 424 if (appl_ptr < appl_ptr1) 425 appl_ptr1 -= runtime->buffer_size; 426 diff = (appl_ptr - appl_ptr1) * play->pcm_salign; 427 if (diff < bytes) { 428 clear_bytes = bytes - diff; 429 bytes = diff; 430 } 431 } 432 433 for (;;) { 434 unsigned int size = bytes; 435 if (src_off + size > play->pcm_buffer_size) 436 size = play->pcm_buffer_size - src_off; 437 if (dst_off + size > capt->pcm_buffer_size) 438 size = capt->pcm_buffer_size - dst_off; 439 memcpy(dst + dst_off, src + src_off, size); 440 capt->silent_size = 0; 441 bytes -= size; 442 if (!bytes) 443 break; 444 src_off = (src_off + size) % play->pcm_buffer_size; 445 dst_off = (dst_off + size) % capt->pcm_buffer_size; 446 } 447 448 if (clear_bytes > 0) { 449 clear_capture_buf(capt, clear_bytes); 450 capt->silent_size = 0; 451 } 452 } 453 454 static inline unsigned int bytepos_delta(struct loopback_pcm *dpcm, 455 unsigned int jiffies_delta) 456 { 457 unsigned long last_pos; 458 unsigned int delta; 459 460 last_pos = byte_pos(dpcm, dpcm->irq_pos); 461 dpcm->irq_pos += jiffies_delta * dpcm->pcm_bps; 462 delta = byte_pos(dpcm, dpcm->irq_pos) - last_pos; 463 if (delta >= dpcm->last_drift) 464 delta -= dpcm->last_drift; 465 dpcm->last_drift = 0; 466 if (dpcm->irq_pos >= dpcm->period_size_frac) { 467 dpcm->irq_pos %= dpcm->period_size_frac; 468 dpcm->period_update_pending = 1; 469 } 470 return delta; 471 } 472 473 static inline void bytepos_finish(struct loopback_pcm *dpcm, 474 unsigned int delta) 475 { 476 dpcm->buf_pos += delta; 477 dpcm->buf_pos %= dpcm->pcm_buffer_size; 478 } 479 480 static unsigned int loopback_pos_update(struct loopback_cable *cable) 481 { 482 struct loopback_pcm *dpcm_play = 483 cable->streams[SNDRV_PCM_STREAM_PLAYBACK]; 484 struct loopback_pcm *dpcm_capt = 485 cable->streams[SNDRV_PCM_STREAM_CAPTURE]; 486 unsigned long delta_play = 0, delta_capt = 0; 487 unsigned int running, count1, count2; 488 unsigned long flags; 489 490 spin_lock_irqsave(&cable->lock, flags); 491 running = cable->running ^ cable->pause; 492 if (running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) { 493 delta_play = jiffies - dpcm_play->last_jiffies; 494 dpcm_play->last_jiffies += delta_play; 495 } 496 497 if (running & (1 << SNDRV_PCM_STREAM_CAPTURE)) { 498 delta_capt = jiffies - dpcm_capt->last_jiffies; 499 dpcm_capt->last_jiffies += delta_capt; 500 } 501 502 if (delta_play == 0 && delta_capt == 0) 503 goto unlock; 504 505 if (delta_play > delta_capt) { 506 count1 = bytepos_delta(dpcm_play, delta_play - delta_capt); 507 bytepos_finish(dpcm_play, count1); 508 delta_play = delta_capt; 509 } else if (delta_play < delta_capt) { 510 count1 = bytepos_delta(dpcm_capt, delta_capt - delta_play); 511 clear_capture_buf(dpcm_capt, count1); 512 bytepos_finish(dpcm_capt, count1); 513 delta_capt = delta_play; 514 } 515 516 if (delta_play == 0 && delta_capt == 0) 517 goto unlock; 518 519 /* note delta_capt == delta_play at this moment */ 520 count1 = bytepos_delta(dpcm_play, delta_play); 521 count2 = bytepos_delta(dpcm_capt, delta_capt); 522 if (count1 < count2) { 523 dpcm_capt->last_drift = count2 - count1; 524 count1 = count2; 525 } else if (count1 > count2) { 526 dpcm_play->last_drift = count1 - count2; 527 } 528 copy_play_buf(dpcm_play, dpcm_capt, count1); 529 bytepos_finish(dpcm_play, count1); 530 bytepos_finish(dpcm_capt, count1); 531 unlock: 532 spin_unlock_irqrestore(&cable->lock, flags); 533 return running; 534 } 535 536 static void loopback_timer_function(unsigned long data) 537 { 538 struct loopback_pcm *dpcm = (struct loopback_pcm *)data; 539 unsigned int running; 540 541 running = loopback_pos_update(dpcm->cable); 542 if (running & (1 << dpcm->substream->stream)) { 543 loopback_timer_start(dpcm); 544 if (dpcm->period_update_pending) { 545 dpcm->period_update_pending = 0; 546 snd_pcm_period_elapsed(dpcm->substream); 547 } 548 } 549 } 550 551 static 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; 555 556 loopback_pos_update(dpcm->cable); 557 return bytes_to_frames(runtime, dpcm->buf_pos); 558 } 559 560 static struct snd_pcm_hardware loopback_pcm_hardware = 561 { 562 .info = (SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_MMAP | 563 SNDRV_PCM_INFO_MMAP_VALID | SNDRV_PCM_INFO_PAUSE), 564 .formats = (SNDRV_PCM_FMTBIT_S16_LE | SNDRV_PCM_FMTBIT_S16_BE | 565 SNDRV_PCM_FMTBIT_S32_LE | SNDRV_PCM_FMTBIT_S32_BE | 566 SNDRV_PCM_FMTBIT_FLOAT_LE | SNDRV_PCM_FMTBIT_FLOAT_BE), 567 .rates = SNDRV_PCM_RATE_CONTINUOUS | SNDRV_PCM_RATE_8000_192000, 568 .rate_min = 8000, 569 .rate_max = 192000, 570 .channels_min = 1, 571 .channels_max = 32, 572 .buffer_bytes_max = 2 * 1024 * 1024, 573 .period_bytes_min = 64, 574 /* note check overflow in frac_pos() using pcm_rate_shift before 575 changing period_bytes_max value */ 576 .period_bytes_max = 1024 * 1024, 577 .periods_min = 1, 578 .periods_max = 1024, 579 .fifo_size = 0, 580 }; 581 582 static void loopback_runtime_free(struct snd_pcm_runtime *runtime) 583 { 584 struct loopback_pcm *dpcm = runtime->private_data; 585 kfree(dpcm); 586 } 587 588 static int loopback_hw_params(struct snd_pcm_substream *substream, 589 struct snd_pcm_hw_params *params) 590 { 591 return snd_pcm_lib_alloc_vmalloc_buffer(substream, 592 params_buffer_bytes(params)); 593 } 594 595 static int loopback_hw_free(struct snd_pcm_substream *substream) 596 { 597 struct snd_pcm_runtime *runtime = substream->runtime; 598 struct loopback_pcm *dpcm = runtime->private_data; 599 struct loopback_cable *cable = dpcm->cable; 600 601 mutex_lock(&dpcm->loopback->cable_lock); 602 cable->valid &= ~(1 << substream->stream); 603 mutex_unlock(&dpcm->loopback->cable_lock); 604 return snd_pcm_lib_free_vmalloc_buffer(substream); 605 } 606 607 static unsigned int get_cable_index(struct snd_pcm_substream *substream) 608 { 609 if (!substream->pcm->device) 610 return substream->stream; 611 else 612 return !substream->stream; 613 } 614 615 static int rule_format(struct snd_pcm_hw_params *params, 616 struct snd_pcm_hw_rule *rule) 617 { 618 619 struct snd_pcm_hardware *hw = rule->private; 620 struct snd_mask *maskp = hw_param_mask(params, rule->var); 621 622 maskp->bits[0] &= (u_int32_t)hw->formats; 623 maskp->bits[1] &= (u_int32_t)(hw->formats >> 32); 624 memset(maskp->bits + 2, 0, (SNDRV_MASK_MAX-64) / 8); /* clear rest */ 625 if (! maskp->bits[0] && ! maskp->bits[1]) 626 return -EINVAL; 627 return 0; 628 } 629 630 static int rule_rate(struct snd_pcm_hw_params *params, 631 struct snd_pcm_hw_rule *rule) 632 { 633 struct snd_pcm_hardware *hw = rule->private; 634 struct snd_interval t; 635 636 t.min = hw->rate_min; 637 t.max = hw->rate_max; 638 t.openmin = t.openmax = 0; 639 t.integer = 0; 640 return snd_interval_refine(hw_param_interval(params, rule->var), &t); 641 } 642 643 static int rule_channels(struct snd_pcm_hw_params *params, 644 struct snd_pcm_hw_rule *rule) 645 { 646 struct snd_pcm_hardware *hw = rule->private; 647 struct snd_interval t; 648 649 t.min = hw->channels_min; 650 t.max = hw->channels_max; 651 t.openmin = t.openmax = 0; 652 t.integer = 0; 653 return snd_interval_refine(hw_param_interval(params, rule->var), &t); 654 } 655 656 static int loopback_open(struct snd_pcm_substream *substream) 657 { 658 struct snd_pcm_runtime *runtime = substream->runtime; 659 struct loopback *loopback = substream->private_data; 660 struct loopback_pcm *dpcm; 661 struct loopback_cable *cable; 662 int err = 0; 663 int dev = get_cable_index(substream); 664 665 mutex_lock(&loopback->cable_lock); 666 dpcm = kzalloc(sizeof(*dpcm), GFP_KERNEL); 667 if (!dpcm) { 668 err = -ENOMEM; 669 goto unlock; 670 } 671 dpcm->loopback = loopback; 672 dpcm->substream = substream; 673 setup_timer(&dpcm->timer, loopback_timer_function, 674 (unsigned long)dpcm); 675 spin_lock_init(&dpcm->timer_lock); 676 677 cable = loopback->cables[substream->number][dev]; 678 if (!cable) { 679 cable = kzalloc(sizeof(*cable), GFP_KERNEL); 680 if (!cable) { 681 kfree(dpcm); 682 err = -ENOMEM; 683 goto unlock; 684 } 685 spin_lock_init(&cable->lock); 686 cable->hw = loopback_pcm_hardware; 687 loopback->cables[substream->number][dev] = cable; 688 } 689 dpcm->cable = cable; 690 cable->streams[substream->stream] = dpcm; 691 692 snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS); 693 694 /* use dynamic rules based on actual runtime->hw values */ 695 /* note that the default rules created in the PCM midlevel code */ 696 /* are cached -> they do not reflect the actual state */ 697 err = snd_pcm_hw_rule_add(runtime, 0, 698 SNDRV_PCM_HW_PARAM_FORMAT, 699 rule_format, &runtime->hw, 700 SNDRV_PCM_HW_PARAM_FORMAT, -1); 701 if (err < 0) 702 goto unlock; 703 err = snd_pcm_hw_rule_add(runtime, 0, 704 SNDRV_PCM_HW_PARAM_RATE, 705 rule_rate, &runtime->hw, 706 SNDRV_PCM_HW_PARAM_RATE, -1); 707 if (err < 0) 708 goto unlock; 709 err = snd_pcm_hw_rule_add(runtime, 0, 710 SNDRV_PCM_HW_PARAM_CHANNELS, 711 rule_channels, &runtime->hw, 712 SNDRV_PCM_HW_PARAM_CHANNELS, -1); 713 if (err < 0) 714 goto unlock; 715 716 runtime->private_data = dpcm; 717 runtime->private_free = loopback_runtime_free; 718 if (get_notify(dpcm)) 719 runtime->hw = loopback_pcm_hardware; 720 else 721 runtime->hw = cable->hw; 722 unlock: 723 mutex_unlock(&loopback->cable_lock); 724 return err; 725 } 726 727 static int loopback_close(struct snd_pcm_substream *substream) 728 { 729 struct loopback *loopback = substream->private_data; 730 struct loopback_pcm *dpcm = substream->runtime->private_data; 731 struct loopback_cable *cable; 732 int dev = get_cable_index(substream); 733 734 loopback_timer_stop(dpcm); 735 mutex_lock(&loopback->cable_lock); 736 cable = loopback->cables[substream->number][dev]; 737 if (cable->streams[!substream->stream]) { 738 /* other stream is still alive */ 739 cable->streams[substream->stream] = NULL; 740 } else { 741 /* free the cable */ 742 loopback->cables[substream->number][dev] = NULL; 743 kfree(cable); 744 } 745 mutex_unlock(&loopback->cable_lock); 746 return 0; 747 } 748 749 static struct snd_pcm_ops loopback_playback_ops = { 750 .open = loopback_open, 751 .close = loopback_close, 752 .ioctl = snd_pcm_lib_ioctl, 753 .hw_params = loopback_hw_params, 754 .hw_free = loopback_hw_free, 755 .prepare = loopback_prepare, 756 .trigger = loopback_trigger, 757 .pointer = loopback_pointer, 758 .page = snd_pcm_lib_get_vmalloc_page, 759 .mmap = snd_pcm_lib_mmap_vmalloc, 760 }; 761 762 static struct snd_pcm_ops loopback_capture_ops = { 763 .open = loopback_open, 764 .close = loopback_close, 765 .ioctl = snd_pcm_lib_ioctl, 766 .hw_params = loopback_hw_params, 767 .hw_free = loopback_hw_free, 768 .prepare = loopback_prepare, 769 .trigger = loopback_trigger, 770 .pointer = loopback_pointer, 771 .page = snd_pcm_lib_get_vmalloc_page, 772 .mmap = snd_pcm_lib_mmap_vmalloc, 773 }; 774 775 static int __devinit loopback_pcm_new(struct loopback *loopback, 776 int device, int substreams) 777 { 778 struct snd_pcm *pcm; 779 int err; 780 781 err = snd_pcm_new(loopback->card, "Loopback PCM", device, 782 substreams, substreams, &pcm); 783 if (err < 0) 784 return err; 785 snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &loopback_playback_ops); 786 snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &loopback_capture_ops); 787 788 pcm->private_data = loopback; 789 pcm->info_flags = 0; 790 strcpy(pcm->name, "Loopback PCM"); 791 792 loopback->pcm[device] = pcm; 793 return 0; 794 } 795 796 static int loopback_rate_shift_info(struct snd_kcontrol *kcontrol, 797 struct snd_ctl_elem_info *uinfo) 798 { 799 uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER; 800 uinfo->count = 1; 801 uinfo->value.integer.min = 80000; 802 uinfo->value.integer.max = 120000; 803 uinfo->value.integer.step = 1; 804 return 0; 805 } 806 807 static int loopback_rate_shift_get(struct snd_kcontrol *kcontrol, 808 struct snd_ctl_elem_value *ucontrol) 809 { 810 struct loopback *loopback = snd_kcontrol_chip(kcontrol); 811 812 ucontrol->value.integer.value[0] = 813 loopback->setup[kcontrol->id.subdevice] 814 [kcontrol->id.device].rate_shift; 815 return 0; 816 } 817 818 static int loopback_rate_shift_put(struct snd_kcontrol *kcontrol, 819 struct snd_ctl_elem_value *ucontrol) 820 { 821 struct loopback *loopback = snd_kcontrol_chip(kcontrol); 822 unsigned int val; 823 int change = 0; 824 825 val = ucontrol->value.integer.value[0]; 826 if (val < 80000) 827 val = 80000; 828 if (val > 120000) 829 val = 120000; 830 mutex_lock(&loopback->cable_lock); 831 if (val != loopback->setup[kcontrol->id.subdevice] 832 [kcontrol->id.device].rate_shift) { 833 loopback->setup[kcontrol->id.subdevice] 834 [kcontrol->id.device].rate_shift = val; 835 change = 1; 836 } 837 mutex_unlock(&loopback->cable_lock); 838 return change; 839 } 840 841 static int loopback_notify_get(struct snd_kcontrol *kcontrol, 842 struct snd_ctl_elem_value *ucontrol) 843 { 844 struct loopback *loopback = snd_kcontrol_chip(kcontrol); 845 846 ucontrol->value.integer.value[0] = 847 loopback->setup[kcontrol->id.subdevice] 848 [kcontrol->id.device].notify; 849 return 0; 850 } 851 852 static int loopback_notify_put(struct snd_kcontrol *kcontrol, 853 struct snd_ctl_elem_value *ucontrol) 854 { 855 struct loopback *loopback = snd_kcontrol_chip(kcontrol); 856 unsigned int val; 857 int change = 0; 858 859 val = ucontrol->value.integer.value[0] ? 1 : 0; 860 if (val != loopback->setup[kcontrol->id.subdevice] 861 [kcontrol->id.device].notify) { 862 loopback->setup[kcontrol->id.subdevice] 863 [kcontrol->id.device].notify = val; 864 change = 1; 865 } 866 return change; 867 } 868 869 static int loopback_active_get(struct snd_kcontrol *kcontrol, 870 struct snd_ctl_elem_value *ucontrol) 871 { 872 struct loopback *loopback = snd_kcontrol_chip(kcontrol); 873 struct loopback_cable *cable = loopback->cables 874 [kcontrol->id.subdevice][kcontrol->id.device ^ 1]; 875 unsigned int val = 0; 876 877 if (cable != NULL) 878 val = (cable->running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) ? 879 1 : 0; 880 ucontrol->value.integer.value[0] = val; 881 return 0; 882 } 883 884 static int loopback_format_info(struct snd_kcontrol *kcontrol, 885 struct snd_ctl_elem_info *uinfo) 886 { 887 uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER; 888 uinfo->count = 1; 889 uinfo->value.integer.min = 0; 890 uinfo->value.integer.max = SNDRV_PCM_FORMAT_LAST; 891 uinfo->value.integer.step = 1; 892 return 0; 893 } 894 895 static int loopback_format_get(struct snd_kcontrol *kcontrol, 896 struct snd_ctl_elem_value *ucontrol) 897 { 898 struct loopback *loopback = snd_kcontrol_chip(kcontrol); 899 900 ucontrol->value.integer.value[0] = 901 loopback->setup[kcontrol->id.subdevice] 902 [kcontrol->id.device].format; 903 return 0; 904 } 905 906 static int loopback_rate_info(struct snd_kcontrol *kcontrol, 907 struct snd_ctl_elem_info *uinfo) 908 { 909 uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER; 910 uinfo->count = 1; 911 uinfo->value.integer.min = 0; 912 uinfo->value.integer.max = 192000; 913 uinfo->value.integer.step = 1; 914 return 0; 915 } 916 917 static int loopback_rate_get(struct snd_kcontrol *kcontrol, 918 struct snd_ctl_elem_value *ucontrol) 919 { 920 struct loopback *loopback = snd_kcontrol_chip(kcontrol); 921 922 ucontrol->value.integer.value[0] = 923 loopback->setup[kcontrol->id.subdevice] 924 [kcontrol->id.device].rate; 925 return 0; 926 } 927 928 static int loopback_channels_info(struct snd_kcontrol *kcontrol, 929 struct snd_ctl_elem_info *uinfo) 930 { 931 uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER; 932 uinfo->count = 1; 933 uinfo->value.integer.min = 1; 934 uinfo->value.integer.max = 1024; 935 uinfo->value.integer.step = 1; 936 return 0; 937 } 938 939 static int loopback_channels_get(struct snd_kcontrol *kcontrol, 940 struct snd_ctl_elem_value *ucontrol) 941 { 942 struct loopback *loopback = snd_kcontrol_chip(kcontrol); 943 944 ucontrol->value.integer.value[0] = 945 loopback->setup[kcontrol->id.subdevice] 946 [kcontrol->id.device].channels; 947 return 0; 948 } 949 950 static struct snd_kcontrol_new loopback_controls[] __devinitdata = { 951 { 952 .iface = SNDRV_CTL_ELEM_IFACE_PCM, 953 .name = "PCM Rate Shift 100000", 954 .info = loopback_rate_shift_info, 955 .get = loopback_rate_shift_get, 956 .put = loopback_rate_shift_put, 957 }, 958 { 959 .iface = SNDRV_CTL_ELEM_IFACE_PCM, 960 .name = "PCM Notify", 961 .info = snd_ctl_boolean_mono_info, 962 .get = loopback_notify_get, 963 .put = loopback_notify_put, 964 }, 965 #define ACTIVE_IDX 2 966 { 967 .access = SNDRV_CTL_ELEM_ACCESS_READ, 968 .iface = SNDRV_CTL_ELEM_IFACE_PCM, 969 .name = "PCM Slave Active", 970 .info = snd_ctl_boolean_mono_info, 971 .get = loopback_active_get, 972 }, 973 #define FORMAT_IDX 3 974 { 975 .access = SNDRV_CTL_ELEM_ACCESS_READ, 976 .iface = SNDRV_CTL_ELEM_IFACE_PCM, 977 .name = "PCM Slave Format", 978 .info = loopback_format_info, 979 .get = loopback_format_get 980 }, 981 #define RATE_IDX 4 982 { 983 .access = SNDRV_CTL_ELEM_ACCESS_READ, 984 .iface = SNDRV_CTL_ELEM_IFACE_PCM, 985 .name = "PCM Slave Rate", 986 .info = loopback_rate_info, 987 .get = loopback_rate_get 988 }, 989 #define CHANNELS_IDX 5 990 { 991 .access = SNDRV_CTL_ELEM_ACCESS_READ, 992 .iface = SNDRV_CTL_ELEM_IFACE_PCM, 993 .name = "PCM Slave Channels", 994 .info = loopback_channels_info, 995 .get = loopback_channels_get 996 } 997 }; 998 999 static int __devinit loopback_mixer_new(struct loopback *loopback, int notify) 1000 { 1001 struct snd_card *card = loopback->card; 1002 struct snd_pcm *pcm; 1003 struct snd_kcontrol *kctl; 1004 struct loopback_setup *setup; 1005 int err, dev, substr, substr_count, idx; 1006 1007 strcpy(card->mixername, "Loopback Mixer"); 1008 for (dev = 0; dev < 2; dev++) { 1009 pcm = loopback->pcm[dev]; 1010 substr_count = 1011 pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream_count; 1012 for (substr = 0; substr < substr_count; substr++) { 1013 setup = &loopback->setup[substr][dev]; 1014 setup->notify = notify; 1015 setup->rate_shift = NO_PITCH; 1016 setup->format = SNDRV_PCM_FORMAT_S16_LE; 1017 setup->rate = 48000; 1018 setup->channels = 2; 1019 for (idx = 0; idx < ARRAY_SIZE(loopback_controls); 1020 idx++) { 1021 kctl = snd_ctl_new1(&loopback_controls[idx], 1022 loopback); 1023 if (!kctl) 1024 return -ENOMEM; 1025 kctl->id.device = dev; 1026 kctl->id.subdevice = substr; 1027 switch (idx) { 1028 case ACTIVE_IDX: 1029 setup->active_id = kctl->id; 1030 break; 1031 case FORMAT_IDX: 1032 setup->format_id = kctl->id; 1033 break; 1034 case RATE_IDX: 1035 setup->rate_id = kctl->id; 1036 break; 1037 case CHANNELS_IDX: 1038 setup->channels_id = kctl->id; 1039 break; 1040 default: 1041 break; 1042 } 1043 err = snd_ctl_add(card, kctl); 1044 if (err < 0) 1045 return err; 1046 } 1047 } 1048 } 1049 return 0; 1050 } 1051 1052 #ifdef CONFIG_PROC_FS 1053 1054 static void print_dpcm_info(struct snd_info_buffer *buffer, 1055 struct loopback_pcm *dpcm, 1056 const char *id) 1057 { 1058 snd_iprintf(buffer, " %s\n", id); 1059 if (dpcm == NULL) { 1060 snd_iprintf(buffer, " inactive\n"); 1061 return; 1062 } 1063 snd_iprintf(buffer, " buffer_size:\t%u\n", dpcm->pcm_buffer_size); 1064 snd_iprintf(buffer, " buffer_pos:\t\t%u\n", dpcm->buf_pos); 1065 snd_iprintf(buffer, " silent_size:\t%u\n", dpcm->silent_size); 1066 snd_iprintf(buffer, " period_size:\t%u\n", dpcm->pcm_period_size); 1067 snd_iprintf(buffer, " bytes_per_sec:\t%u\n", dpcm->pcm_bps); 1068 snd_iprintf(buffer, " sample_align:\t%u\n", dpcm->pcm_salign); 1069 snd_iprintf(buffer, " rate_shift:\t\t%u\n", dpcm->pcm_rate_shift); 1070 snd_iprintf(buffer, " update_pending:\t%u\n", 1071 dpcm->period_update_pending); 1072 snd_iprintf(buffer, " irq_pos:\t\t%u\n", dpcm->irq_pos); 1073 snd_iprintf(buffer, " period_frac:\t%u\n", dpcm->period_size_frac); 1074 snd_iprintf(buffer, " last_jiffies:\t%lu (%lu)\n", 1075 dpcm->last_jiffies, jiffies); 1076 snd_iprintf(buffer, " timer_expires:\t%lu\n", dpcm->timer.expires); 1077 } 1078 1079 static void print_substream_info(struct snd_info_buffer *buffer, 1080 struct loopback *loopback, 1081 int sub, 1082 int num) 1083 { 1084 struct loopback_cable *cable = loopback->cables[sub][num]; 1085 1086 snd_iprintf(buffer, "Cable %i substream %i:\n", num, sub); 1087 if (cable == NULL) { 1088 snd_iprintf(buffer, " inactive\n"); 1089 return; 1090 } 1091 snd_iprintf(buffer, " valid: %u\n", cable->valid); 1092 snd_iprintf(buffer, " running: %u\n", cable->running); 1093 snd_iprintf(buffer, " pause: %u\n", cable->pause); 1094 print_dpcm_info(buffer, cable->streams[0], "Playback"); 1095 print_dpcm_info(buffer, cable->streams[1], "Capture"); 1096 } 1097 1098 static void print_cable_info(struct snd_info_entry *entry, 1099 struct snd_info_buffer *buffer) 1100 { 1101 struct loopback *loopback = entry->private_data; 1102 int sub, num; 1103 1104 mutex_lock(&loopback->cable_lock); 1105 num = entry->name[strlen(entry->name)-1]; 1106 num = num == '0' ? 0 : 1; 1107 for (sub = 0; sub < MAX_PCM_SUBSTREAMS; sub++) 1108 print_substream_info(buffer, loopback, sub, num); 1109 mutex_unlock(&loopback->cable_lock); 1110 } 1111 1112 static int __devinit loopback_proc_new(struct loopback *loopback, int cidx) 1113 { 1114 char name[32]; 1115 struct snd_info_entry *entry; 1116 int err; 1117 1118 snprintf(name, sizeof(name), "cable#%d", cidx); 1119 err = snd_card_proc_new(loopback->card, name, &entry); 1120 if (err < 0) 1121 return err; 1122 1123 snd_info_set_text_ops(entry, loopback, print_cable_info); 1124 return 0; 1125 } 1126 1127 #else /* !CONFIG_PROC_FS */ 1128 1129 #define loopback_proc_new(loopback, cidx) do { } while (0) 1130 1131 #endif 1132 1133 static int __devinit loopback_probe(struct platform_device *devptr) 1134 { 1135 struct snd_card *card; 1136 struct loopback *loopback; 1137 int dev = devptr->id; 1138 int err; 1139 1140 err = snd_card_create(index[dev], id[dev], THIS_MODULE, 1141 sizeof(struct loopback), &card); 1142 if (err < 0) 1143 return err; 1144 loopback = card->private_data; 1145 1146 if (pcm_substreams[dev] < 1) 1147 pcm_substreams[dev] = 1; 1148 if (pcm_substreams[dev] > MAX_PCM_SUBSTREAMS) 1149 pcm_substreams[dev] = MAX_PCM_SUBSTREAMS; 1150 1151 loopback->card = card; 1152 mutex_init(&loopback->cable_lock); 1153 1154 err = loopback_pcm_new(loopback, 0, pcm_substreams[dev]); 1155 if (err < 0) 1156 goto __nodev; 1157 err = loopback_pcm_new(loopback, 1, pcm_substreams[dev]); 1158 if (err < 0) 1159 goto __nodev; 1160 err = loopback_mixer_new(loopback, pcm_notify[dev] ? 1 : 0); 1161 if (err < 0) 1162 goto __nodev; 1163 loopback_proc_new(loopback, 0); 1164 loopback_proc_new(loopback, 1); 1165 strcpy(card->driver, "Loopback"); 1166 strcpy(card->shortname, "Loopback"); 1167 sprintf(card->longname, "Loopback %i", dev + 1); 1168 err = snd_card_register(card); 1169 if (!err) { 1170 platform_set_drvdata(devptr, card); 1171 return 0; 1172 } 1173 __nodev: 1174 snd_card_free(card); 1175 return err; 1176 } 1177 1178 static int __devexit loopback_remove(struct platform_device *devptr) 1179 { 1180 snd_card_free(platform_get_drvdata(devptr)); 1181 platform_set_drvdata(devptr, NULL); 1182 return 0; 1183 } 1184 1185 #ifdef CONFIG_PM_SLEEP 1186 static int loopback_suspend(struct device *pdev) 1187 { 1188 struct snd_card *card = dev_get_drvdata(pdev); 1189 struct loopback *loopback = card->private_data; 1190 1191 snd_power_change_state(card, SNDRV_CTL_POWER_D3hot); 1192 1193 snd_pcm_suspend_all(loopback->pcm[0]); 1194 snd_pcm_suspend_all(loopback->pcm[1]); 1195 return 0; 1196 } 1197 1198 static int loopback_resume(struct device *pdev) 1199 { 1200 struct snd_card *card = dev_get_drvdata(pdev); 1201 1202 snd_power_change_state(card, SNDRV_CTL_POWER_D0); 1203 return 0; 1204 } 1205 1206 static SIMPLE_DEV_PM_OPS(loopback_pm, loopback_suspend, loopback_resume); 1207 #define LOOPBACK_PM_OPS &loopback_pm 1208 #else 1209 #define LOOPBACK_PM_OPS NULL 1210 #endif 1211 1212 #define SND_LOOPBACK_DRIVER "snd_aloop" 1213 1214 static struct platform_driver loopback_driver = { 1215 .probe = loopback_probe, 1216 .remove = __devexit_p(loopback_remove), 1217 .driver = { 1218 .name = SND_LOOPBACK_DRIVER, 1219 .owner = THIS_MODULE, 1220 .pm = LOOPBACK_PM_OPS, 1221 }, 1222 }; 1223 1224 static void loopback_unregister_all(void) 1225 { 1226 int i; 1227 1228 for (i = 0; i < ARRAY_SIZE(devices); ++i) 1229 platform_device_unregister(devices[i]); 1230 platform_driver_unregister(&loopback_driver); 1231 } 1232 1233 static int __init alsa_card_loopback_init(void) 1234 { 1235 int i, err, cards; 1236 1237 err = platform_driver_register(&loopback_driver); 1238 if (err < 0) 1239 return err; 1240 1241 1242 cards = 0; 1243 for (i = 0; i < SNDRV_CARDS; i++) { 1244 struct platform_device *device; 1245 if (!enable[i]) 1246 continue; 1247 device = platform_device_register_simple(SND_LOOPBACK_DRIVER, 1248 i, NULL, 0); 1249 if (IS_ERR(device)) 1250 continue; 1251 if (!platform_get_drvdata(device)) { 1252 platform_device_unregister(device); 1253 continue; 1254 } 1255 devices[i] = device; 1256 cards++; 1257 } 1258 if (!cards) { 1259 #ifdef MODULE 1260 printk(KERN_ERR "aloop: No loopback enabled\n"); 1261 #endif 1262 loopback_unregister_all(); 1263 return -ENODEV; 1264 } 1265 return 0; 1266 } 1267 1268 static void __exit alsa_card_loopback_exit(void) 1269 { 1270 loopback_unregister_all(); 1271 } 1272 1273 module_init(alsa_card_loopback_init) 1274 module_exit(alsa_card_loopback_exit) 1275