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/pcm_params.h> 43 #include <sound/info.h> 44 #include <sound/initval.h> 45 46 MODULE_AUTHOR("Jaroslav Kysela <perex@perex.cz>"); 47 MODULE_DESCRIPTION("A loopback soundcard"); 48 MODULE_LICENSE("GPL"); 49 MODULE_SUPPORTED_DEVICE("{{ALSA,Loopback soundcard}}"); 50 51 #define MAX_PCM_SUBSTREAMS 8 52 53 static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX; /* Index 0-MAX */ 54 static char *id[SNDRV_CARDS] = SNDRV_DEFAULT_STR; /* ID for this card */ 55 static bool enable[SNDRV_CARDS] = {1, [1 ... (SNDRV_CARDS - 1)] = 0}; 56 static int pcm_substreams[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 8}; 57 static int pcm_notify[SNDRV_CARDS]; 58 59 module_param_array(index, int, NULL, 0444); 60 MODULE_PARM_DESC(index, "Index value for loopback soundcard."); 61 module_param_array(id, charp, NULL, 0444); 62 MODULE_PARM_DESC(id, "ID string for loopback soundcard."); 63 module_param_array(enable, bool, NULL, 0444); 64 MODULE_PARM_DESC(enable, "Enable this loopback soundcard."); 65 module_param_array(pcm_substreams, int, NULL, 0444); 66 MODULE_PARM_DESC(pcm_substreams, "PCM substreams # (1-8) for loopback driver."); 67 module_param_array(pcm_notify, int, NULL, 0444); 68 MODULE_PARM_DESC(pcm_notify, "Break capture when PCM format/rate/channels changes."); 69 70 #define NO_PITCH 100000 71 72 struct loopback_pcm; 73 74 struct loopback_cable { 75 spinlock_t lock; 76 struct loopback_pcm *streams[2]; 77 struct snd_pcm_hardware hw; 78 /* flags */ 79 unsigned int valid; 80 unsigned int running; 81 unsigned int pause; 82 }; 83 84 struct loopback_setup { 85 unsigned int notify: 1; 86 unsigned int rate_shift; 87 unsigned int format; 88 unsigned int rate; 89 unsigned int channels; 90 struct snd_ctl_elem_id active_id; 91 struct snd_ctl_elem_id format_id; 92 struct snd_ctl_elem_id rate_id; 93 struct snd_ctl_elem_id channels_id; 94 }; 95 96 struct loopback { 97 struct snd_card *card; 98 struct mutex cable_lock; 99 struct loopback_cable *cables[MAX_PCM_SUBSTREAMS][2]; 100 struct snd_pcm *pcm[2]; 101 struct loopback_setup setup[MAX_PCM_SUBSTREAMS][2]; 102 }; 103 104 struct loopback_pcm { 105 struct loopback *loopback; 106 struct snd_pcm_substream *substream; 107 struct loopback_cable *cable; 108 unsigned int pcm_buffer_size; 109 unsigned int buf_pos; /* position in buffer */ 110 unsigned int silent_size; 111 /* PCM parameters */ 112 unsigned int pcm_period_size; 113 unsigned int pcm_bps; /* bytes per second */ 114 unsigned int pcm_salign; /* bytes per sample * channels */ 115 unsigned int pcm_rate_shift; /* rate shift value */ 116 /* flags */ 117 unsigned int period_update_pending :1; 118 /* timer stuff */ 119 unsigned int irq_pos; /* fractional IRQ position */ 120 unsigned int period_size_frac; 121 unsigned int last_drift; 122 unsigned long last_jiffies; 123 struct timer_list timer; 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 /* call in cable->lock */ 170 static void loopback_timer_start(struct loopback_pcm *dpcm) 171 { 172 unsigned long tick; 173 unsigned int rate_shift = get_rate_shift(dpcm); 174 175 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 mod_timer(&dpcm->timer, jiffies + tick); 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 case SNDRV_PCM_TRIGGER_SUSPEND: 290 spin_lock(&cable->lock); 291 cable->pause |= stream; 292 loopback_timer_stop(dpcm); 293 spin_unlock(&cable->lock); 294 break; 295 case SNDRV_PCM_TRIGGER_PAUSE_RELEASE: 296 case SNDRV_PCM_TRIGGER_RESUME: 297 spin_lock(&cable->lock); 298 dpcm->last_jiffies = jiffies; 299 cable->pause &= ~stream; 300 loopback_timer_start(dpcm); 301 spin_unlock(&cable->lock); 302 break; 303 default: 304 return -EINVAL; 305 } 306 return 0; 307 } 308 309 static void params_change(struct snd_pcm_substream *substream) 310 { 311 struct snd_pcm_runtime *runtime = substream->runtime; 312 struct loopback_pcm *dpcm = runtime->private_data; 313 struct loopback_cable *cable = dpcm->cable; 314 315 cable->hw.formats = pcm_format_to_bits(runtime->format); 316 cable->hw.rate_min = runtime->rate; 317 cable->hw.rate_max = runtime->rate; 318 cable->hw.channels_min = runtime->channels; 319 cable->hw.channels_max = runtime->channels; 320 } 321 322 static int loopback_prepare(struct snd_pcm_substream *substream) 323 { 324 struct snd_pcm_runtime *runtime = substream->runtime; 325 struct loopback_pcm *dpcm = runtime->private_data; 326 struct loopback_cable *cable = dpcm->cable; 327 int bps, salign; 328 329 salign = (snd_pcm_format_width(runtime->format) * 330 runtime->channels) / 8; 331 bps = salign * runtime->rate; 332 if (bps <= 0 || salign <= 0) 333 return -EINVAL; 334 335 dpcm->buf_pos = 0; 336 dpcm->pcm_buffer_size = frames_to_bytes(runtime, runtime->buffer_size); 337 if (substream->stream == SNDRV_PCM_STREAM_CAPTURE) { 338 /* clear capture buffer */ 339 dpcm->silent_size = dpcm->pcm_buffer_size; 340 snd_pcm_format_set_silence(runtime->format, runtime->dma_area, 341 runtime->buffer_size * runtime->channels); 342 } 343 344 dpcm->irq_pos = 0; 345 dpcm->period_update_pending = 0; 346 dpcm->pcm_bps = bps; 347 dpcm->pcm_salign = salign; 348 dpcm->pcm_period_size = frames_to_bytes(runtime, runtime->period_size); 349 350 mutex_lock(&dpcm->loopback->cable_lock); 351 if (!(cable->valid & ~(1 << substream->stream)) || 352 (get_setup(dpcm)->notify && 353 substream->stream == SNDRV_PCM_STREAM_PLAYBACK)) 354 params_change(substream); 355 cable->valid |= 1 << substream->stream; 356 mutex_unlock(&dpcm->loopback->cable_lock); 357 358 return 0; 359 } 360 361 static void clear_capture_buf(struct loopback_pcm *dpcm, unsigned int bytes) 362 { 363 struct snd_pcm_runtime *runtime = dpcm->substream->runtime; 364 char *dst = runtime->dma_area; 365 unsigned int dst_off = dpcm->buf_pos; 366 367 if (dpcm->silent_size >= dpcm->pcm_buffer_size) 368 return; 369 if (dpcm->silent_size + bytes > dpcm->pcm_buffer_size) 370 bytes = dpcm->pcm_buffer_size - dpcm->silent_size; 371 372 for (;;) { 373 unsigned int size = bytes; 374 if (dst_off + size > dpcm->pcm_buffer_size) 375 size = dpcm->pcm_buffer_size - dst_off; 376 snd_pcm_format_set_silence(runtime->format, dst + dst_off, 377 bytes_to_frames(runtime, size) * 378 runtime->channels); 379 dpcm->silent_size += size; 380 bytes -= size; 381 if (!bytes) 382 break; 383 dst_off = 0; 384 } 385 } 386 387 static void copy_play_buf(struct loopback_pcm *play, 388 struct loopback_pcm *capt, 389 unsigned int bytes) 390 { 391 struct snd_pcm_runtime *runtime = play->substream->runtime; 392 char *src = runtime->dma_area; 393 char *dst = capt->substream->runtime->dma_area; 394 unsigned int src_off = play->buf_pos; 395 unsigned int dst_off = capt->buf_pos; 396 unsigned int clear_bytes = 0; 397 398 /* check if playback is draining, trim the capture copy size 399 * when our pointer is at the end of playback ring buffer */ 400 if (runtime->status->state == SNDRV_PCM_STATE_DRAINING && 401 snd_pcm_playback_hw_avail(runtime) < runtime->buffer_size) { 402 snd_pcm_uframes_t appl_ptr, appl_ptr1, diff; 403 appl_ptr = appl_ptr1 = runtime->control->appl_ptr; 404 appl_ptr1 -= appl_ptr1 % runtime->buffer_size; 405 appl_ptr1 += play->buf_pos / play->pcm_salign; 406 if (appl_ptr < appl_ptr1) 407 appl_ptr1 -= runtime->buffer_size; 408 diff = (appl_ptr - appl_ptr1) * play->pcm_salign; 409 if (diff < bytes) { 410 clear_bytes = bytes - diff; 411 bytes = diff; 412 } 413 } 414 415 for (;;) { 416 unsigned int size = bytes; 417 if (src_off + size > play->pcm_buffer_size) 418 size = play->pcm_buffer_size - src_off; 419 if (dst_off + size > capt->pcm_buffer_size) 420 size = capt->pcm_buffer_size - dst_off; 421 memcpy(dst + dst_off, src + src_off, size); 422 capt->silent_size = 0; 423 bytes -= size; 424 if (!bytes) 425 break; 426 src_off = (src_off + size) % play->pcm_buffer_size; 427 dst_off = (dst_off + size) % capt->pcm_buffer_size; 428 } 429 430 if (clear_bytes > 0) { 431 clear_capture_buf(capt, clear_bytes); 432 capt->silent_size = 0; 433 } 434 } 435 436 static inline unsigned int bytepos_delta(struct loopback_pcm *dpcm, 437 unsigned int jiffies_delta) 438 { 439 unsigned long last_pos; 440 unsigned int delta; 441 442 last_pos = byte_pos(dpcm, dpcm->irq_pos); 443 dpcm->irq_pos += jiffies_delta * dpcm->pcm_bps; 444 delta = byte_pos(dpcm, dpcm->irq_pos) - last_pos; 445 if (delta >= dpcm->last_drift) 446 delta -= dpcm->last_drift; 447 dpcm->last_drift = 0; 448 if (dpcm->irq_pos >= dpcm->period_size_frac) { 449 dpcm->irq_pos %= dpcm->period_size_frac; 450 dpcm->period_update_pending = 1; 451 } 452 return delta; 453 } 454 455 static inline void bytepos_finish(struct loopback_pcm *dpcm, 456 unsigned int delta) 457 { 458 dpcm->buf_pos += delta; 459 dpcm->buf_pos %= dpcm->pcm_buffer_size; 460 } 461 462 /* call in cable->lock */ 463 static unsigned int loopback_pos_update(struct loopback_cable *cable) 464 { 465 struct loopback_pcm *dpcm_play = 466 cable->streams[SNDRV_PCM_STREAM_PLAYBACK]; 467 struct loopback_pcm *dpcm_capt = 468 cable->streams[SNDRV_PCM_STREAM_CAPTURE]; 469 unsigned long delta_play = 0, delta_capt = 0; 470 unsigned int running, count1, count2; 471 472 running = cable->running ^ cable->pause; 473 if (running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) { 474 delta_play = jiffies - dpcm_play->last_jiffies; 475 dpcm_play->last_jiffies += delta_play; 476 } 477 478 if (running & (1 << SNDRV_PCM_STREAM_CAPTURE)) { 479 delta_capt = jiffies - dpcm_capt->last_jiffies; 480 dpcm_capt->last_jiffies += delta_capt; 481 } 482 483 if (delta_play == 0 && delta_capt == 0) 484 goto unlock; 485 486 if (delta_play > delta_capt) { 487 count1 = bytepos_delta(dpcm_play, delta_play - delta_capt); 488 bytepos_finish(dpcm_play, count1); 489 delta_play = delta_capt; 490 } else if (delta_play < delta_capt) { 491 count1 = bytepos_delta(dpcm_capt, delta_capt - delta_play); 492 clear_capture_buf(dpcm_capt, count1); 493 bytepos_finish(dpcm_capt, count1); 494 delta_capt = delta_play; 495 } 496 497 if (delta_play == 0 && delta_capt == 0) 498 goto unlock; 499 500 /* note delta_capt == delta_play at this moment */ 501 count1 = bytepos_delta(dpcm_play, delta_play); 502 count2 = bytepos_delta(dpcm_capt, delta_capt); 503 if (count1 < count2) { 504 dpcm_capt->last_drift = count2 - count1; 505 count1 = count2; 506 } else if (count1 > count2) { 507 dpcm_play->last_drift = count1 - count2; 508 } 509 copy_play_buf(dpcm_play, dpcm_capt, count1); 510 bytepos_finish(dpcm_play, count1); 511 bytepos_finish(dpcm_capt, count1); 512 unlock: 513 return running; 514 } 515 516 static void loopback_timer_function(struct timer_list *t) 517 { 518 struct loopback_pcm *dpcm = from_timer(dpcm, t, timer); 519 unsigned long flags; 520 521 spin_lock_irqsave(&dpcm->cable->lock, flags); 522 if (loopback_pos_update(dpcm->cable) & (1 << dpcm->substream->stream)) { 523 loopback_timer_start(dpcm); 524 if (dpcm->period_update_pending) { 525 dpcm->period_update_pending = 0; 526 spin_unlock_irqrestore(&dpcm->cable->lock, flags); 527 /* need to unlock before calling below */ 528 snd_pcm_period_elapsed(dpcm->substream); 529 return; 530 } 531 } 532 spin_unlock_irqrestore(&dpcm->cable->lock, flags); 533 } 534 535 static snd_pcm_uframes_t loopback_pointer(struct snd_pcm_substream *substream) 536 { 537 struct snd_pcm_runtime *runtime = substream->runtime; 538 struct loopback_pcm *dpcm = runtime->private_data; 539 snd_pcm_uframes_t pos; 540 541 spin_lock(&dpcm->cable->lock); 542 loopback_pos_update(dpcm->cable); 543 pos = dpcm->buf_pos; 544 spin_unlock(&dpcm->cable->lock); 545 return bytes_to_frames(runtime, pos); 546 } 547 548 static const struct snd_pcm_hardware loopback_pcm_hardware = 549 { 550 .info = (SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_MMAP | 551 SNDRV_PCM_INFO_MMAP_VALID | SNDRV_PCM_INFO_PAUSE | 552 SNDRV_PCM_INFO_RESUME), 553 .formats = (SNDRV_PCM_FMTBIT_S16_LE | SNDRV_PCM_FMTBIT_S16_BE | 554 SNDRV_PCM_FMTBIT_S32_LE | SNDRV_PCM_FMTBIT_S32_BE | 555 SNDRV_PCM_FMTBIT_FLOAT_LE | SNDRV_PCM_FMTBIT_FLOAT_BE), 556 .rates = SNDRV_PCM_RATE_CONTINUOUS | SNDRV_PCM_RATE_8000_192000, 557 .rate_min = 8000, 558 .rate_max = 192000, 559 .channels_min = 1, 560 .channels_max = 32, 561 .buffer_bytes_max = 2 * 1024 * 1024, 562 .period_bytes_min = 64, 563 /* note check overflow in frac_pos() using pcm_rate_shift before 564 changing period_bytes_max value */ 565 .period_bytes_max = 1024 * 1024, 566 .periods_min = 1, 567 .periods_max = 1024, 568 .fifo_size = 0, 569 }; 570 571 static void loopback_runtime_free(struct snd_pcm_runtime *runtime) 572 { 573 struct loopback_pcm *dpcm = runtime->private_data; 574 kfree(dpcm); 575 } 576 577 static int loopback_hw_params(struct snd_pcm_substream *substream, 578 struct snd_pcm_hw_params *params) 579 { 580 return snd_pcm_lib_alloc_vmalloc_buffer(substream, 581 params_buffer_bytes(params)); 582 } 583 584 static int loopback_hw_free(struct snd_pcm_substream *substream) 585 { 586 struct snd_pcm_runtime *runtime = substream->runtime; 587 struct loopback_pcm *dpcm = runtime->private_data; 588 struct loopback_cable *cable = dpcm->cable; 589 590 mutex_lock(&dpcm->loopback->cable_lock); 591 cable->valid &= ~(1 << substream->stream); 592 mutex_unlock(&dpcm->loopback->cable_lock); 593 return snd_pcm_lib_free_vmalloc_buffer(substream); 594 } 595 596 static unsigned int get_cable_index(struct snd_pcm_substream *substream) 597 { 598 if (!substream->pcm->device) 599 return substream->stream; 600 else 601 return !substream->stream; 602 } 603 604 static int rule_format(struct snd_pcm_hw_params *params, 605 struct snd_pcm_hw_rule *rule) 606 { 607 struct loopback_pcm *dpcm = rule->private; 608 struct loopback_cable *cable = dpcm->cable; 609 struct snd_mask m; 610 611 snd_mask_none(&m); 612 mutex_lock(&dpcm->loopback->cable_lock); 613 m.bits[0] = (u_int32_t)cable->hw.formats; 614 m.bits[1] = (u_int32_t)(cable->hw.formats >> 32); 615 mutex_unlock(&dpcm->loopback->cable_lock); 616 return snd_mask_refine(hw_param_mask(params, rule->var), &m); 617 } 618 619 static int rule_rate(struct snd_pcm_hw_params *params, 620 struct snd_pcm_hw_rule *rule) 621 { 622 struct loopback_pcm *dpcm = rule->private; 623 struct loopback_cable *cable = dpcm->cable; 624 struct snd_interval t; 625 626 mutex_lock(&dpcm->loopback->cable_lock); 627 t.min = cable->hw.rate_min; 628 t.max = cable->hw.rate_max; 629 mutex_unlock(&dpcm->loopback->cable_lock); 630 t.openmin = t.openmax = 0; 631 t.integer = 0; 632 return snd_interval_refine(hw_param_interval(params, rule->var), &t); 633 } 634 635 static int rule_channels(struct snd_pcm_hw_params *params, 636 struct snd_pcm_hw_rule *rule) 637 { 638 struct loopback_pcm *dpcm = rule->private; 639 struct loopback_cable *cable = dpcm->cable; 640 struct snd_interval t; 641 642 mutex_lock(&dpcm->loopback->cable_lock); 643 t.min = cable->hw.channels_min; 644 t.max = cable->hw.channels_max; 645 mutex_unlock(&dpcm->loopback->cable_lock); 646 t.openmin = t.openmax = 0; 647 t.integer = 0; 648 return snd_interval_refine(hw_param_interval(params, rule->var), &t); 649 } 650 651 static void free_cable(struct snd_pcm_substream *substream) 652 { 653 struct loopback *loopback = substream->private_data; 654 int dev = get_cable_index(substream); 655 struct loopback_cable *cable; 656 657 cable = loopback->cables[substream->number][dev]; 658 if (!cable) 659 return; 660 if (cable->streams[!substream->stream]) { 661 /* other stream is still alive */ 662 cable->streams[substream->stream] = NULL; 663 } else { 664 /* free the cable */ 665 loopback->cables[substream->number][dev] = NULL; 666 kfree(cable); 667 } 668 } 669 670 static int loopback_open(struct snd_pcm_substream *substream) 671 { 672 struct snd_pcm_runtime *runtime = substream->runtime; 673 struct loopback *loopback = substream->private_data; 674 struct loopback_pcm *dpcm; 675 struct loopback_cable *cable = NULL; 676 int err = 0; 677 int dev = get_cable_index(substream); 678 679 mutex_lock(&loopback->cable_lock); 680 dpcm = kzalloc(sizeof(*dpcm), GFP_KERNEL); 681 if (!dpcm) { 682 err = -ENOMEM; 683 goto unlock; 684 } 685 dpcm->loopback = loopback; 686 dpcm->substream = substream; 687 timer_setup(&dpcm->timer, loopback_timer_function, 0); 688 689 cable = loopback->cables[substream->number][dev]; 690 if (!cable) { 691 cable = kzalloc(sizeof(*cable), GFP_KERNEL); 692 if (!cable) { 693 err = -ENOMEM; 694 goto unlock; 695 } 696 spin_lock_init(&cable->lock); 697 cable->hw = loopback_pcm_hardware; 698 loopback->cables[substream->number][dev] = cable; 699 } 700 dpcm->cable = cable; 701 cable->streams[substream->stream] = dpcm; 702 703 snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS); 704 705 /* use dynamic rules based on actual runtime->hw values */ 706 /* note that the default rules created in the PCM midlevel code */ 707 /* are cached -> they do not reflect the actual state */ 708 err = snd_pcm_hw_rule_add(runtime, 0, 709 SNDRV_PCM_HW_PARAM_FORMAT, 710 rule_format, dpcm, 711 SNDRV_PCM_HW_PARAM_FORMAT, -1); 712 if (err < 0) 713 goto unlock; 714 err = snd_pcm_hw_rule_add(runtime, 0, 715 SNDRV_PCM_HW_PARAM_RATE, 716 rule_rate, dpcm, 717 SNDRV_PCM_HW_PARAM_RATE, -1); 718 if (err < 0) 719 goto unlock; 720 err = snd_pcm_hw_rule_add(runtime, 0, 721 SNDRV_PCM_HW_PARAM_CHANNELS, 722 rule_channels, dpcm, 723 SNDRV_PCM_HW_PARAM_CHANNELS, -1); 724 if (err < 0) 725 goto unlock; 726 727 runtime->private_data = dpcm; 728 runtime->private_free = loopback_runtime_free; 729 if (get_notify(dpcm)) 730 runtime->hw = loopback_pcm_hardware; 731 else 732 runtime->hw = cable->hw; 733 unlock: 734 if (err < 0) { 735 free_cable(substream); 736 kfree(dpcm); 737 } 738 mutex_unlock(&loopback->cable_lock); 739 return err; 740 } 741 742 static int loopback_close(struct snd_pcm_substream *substream) 743 { 744 struct loopback *loopback = substream->private_data; 745 struct loopback_pcm *dpcm = substream->runtime->private_data; 746 747 loopback_timer_stop(dpcm); 748 mutex_lock(&loopback->cable_lock); 749 free_cable(substream); 750 mutex_unlock(&loopback->cable_lock); 751 return 0; 752 } 753 754 static const struct snd_pcm_ops loopback_playback_ops = { 755 .open = loopback_open, 756 .close = loopback_close, 757 .ioctl = snd_pcm_lib_ioctl, 758 .hw_params = loopback_hw_params, 759 .hw_free = loopback_hw_free, 760 .prepare = loopback_prepare, 761 .trigger = loopback_trigger, 762 .pointer = loopback_pointer, 763 .page = snd_pcm_lib_get_vmalloc_page, 764 .mmap = snd_pcm_lib_mmap_vmalloc, 765 }; 766 767 static const struct snd_pcm_ops loopback_capture_ops = { 768 .open = loopback_open, 769 .close = loopback_close, 770 .ioctl = snd_pcm_lib_ioctl, 771 .hw_params = loopback_hw_params, 772 .hw_free = loopback_hw_free, 773 .prepare = loopback_prepare, 774 .trigger = loopback_trigger, 775 .pointer = loopback_pointer, 776 .page = snd_pcm_lib_get_vmalloc_page, 777 .mmap = snd_pcm_lib_mmap_vmalloc, 778 }; 779 780 static int loopback_pcm_new(struct loopback *loopback, 781 int device, int substreams) 782 { 783 struct snd_pcm *pcm; 784 int err; 785 786 err = snd_pcm_new(loopback->card, "Loopback PCM", device, 787 substreams, substreams, &pcm); 788 if (err < 0) 789 return err; 790 snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &loopback_playback_ops); 791 snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &loopback_capture_ops); 792 793 pcm->private_data = loopback; 794 pcm->info_flags = 0; 795 strcpy(pcm->name, "Loopback PCM"); 796 797 loopback->pcm[device] = pcm; 798 return 0; 799 } 800 801 static int loopback_rate_shift_info(struct snd_kcontrol *kcontrol, 802 struct snd_ctl_elem_info *uinfo) 803 { 804 uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER; 805 uinfo->count = 1; 806 uinfo->value.integer.min = 80000; 807 uinfo->value.integer.max = 120000; 808 uinfo->value.integer.step = 1; 809 return 0; 810 } 811 812 static int loopback_rate_shift_get(struct snd_kcontrol *kcontrol, 813 struct snd_ctl_elem_value *ucontrol) 814 { 815 struct loopback *loopback = snd_kcontrol_chip(kcontrol); 816 817 ucontrol->value.integer.value[0] = 818 loopback->setup[kcontrol->id.subdevice] 819 [kcontrol->id.device].rate_shift; 820 return 0; 821 } 822 823 static int loopback_rate_shift_put(struct snd_kcontrol *kcontrol, 824 struct snd_ctl_elem_value *ucontrol) 825 { 826 struct loopback *loopback = snd_kcontrol_chip(kcontrol); 827 unsigned int val; 828 int change = 0; 829 830 val = ucontrol->value.integer.value[0]; 831 if (val < 80000) 832 val = 80000; 833 if (val > 120000) 834 val = 120000; 835 mutex_lock(&loopback->cable_lock); 836 if (val != loopback->setup[kcontrol->id.subdevice] 837 [kcontrol->id.device].rate_shift) { 838 loopback->setup[kcontrol->id.subdevice] 839 [kcontrol->id.device].rate_shift = val; 840 change = 1; 841 } 842 mutex_unlock(&loopback->cable_lock); 843 return change; 844 } 845 846 static int loopback_notify_get(struct snd_kcontrol *kcontrol, 847 struct snd_ctl_elem_value *ucontrol) 848 { 849 struct loopback *loopback = snd_kcontrol_chip(kcontrol); 850 851 ucontrol->value.integer.value[0] = 852 loopback->setup[kcontrol->id.subdevice] 853 [kcontrol->id.device].notify; 854 return 0; 855 } 856 857 static int loopback_notify_put(struct snd_kcontrol *kcontrol, 858 struct snd_ctl_elem_value *ucontrol) 859 { 860 struct loopback *loopback = snd_kcontrol_chip(kcontrol); 861 unsigned int val; 862 int change = 0; 863 864 val = ucontrol->value.integer.value[0] ? 1 : 0; 865 if (val != loopback->setup[kcontrol->id.subdevice] 866 [kcontrol->id.device].notify) { 867 loopback->setup[kcontrol->id.subdevice] 868 [kcontrol->id.device].notify = val; 869 change = 1; 870 } 871 return change; 872 } 873 874 static int loopback_active_get(struct snd_kcontrol *kcontrol, 875 struct snd_ctl_elem_value *ucontrol) 876 { 877 struct loopback *loopback = snd_kcontrol_chip(kcontrol); 878 struct loopback_cable *cable = loopback->cables 879 [kcontrol->id.subdevice][kcontrol->id.device ^ 1]; 880 unsigned int val = 0; 881 882 if (cable != NULL) 883 val = (cable->running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) ? 884 1 : 0; 885 ucontrol->value.integer.value[0] = val; 886 return 0; 887 } 888 889 static int loopback_format_info(struct snd_kcontrol *kcontrol, 890 struct snd_ctl_elem_info *uinfo) 891 { 892 uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER; 893 uinfo->count = 1; 894 uinfo->value.integer.min = 0; 895 uinfo->value.integer.max = SNDRV_PCM_FORMAT_LAST; 896 uinfo->value.integer.step = 1; 897 return 0; 898 } 899 900 static int loopback_format_get(struct snd_kcontrol *kcontrol, 901 struct snd_ctl_elem_value *ucontrol) 902 { 903 struct loopback *loopback = snd_kcontrol_chip(kcontrol); 904 905 ucontrol->value.integer.value[0] = 906 loopback->setup[kcontrol->id.subdevice] 907 [kcontrol->id.device].format; 908 return 0; 909 } 910 911 static int loopback_rate_info(struct snd_kcontrol *kcontrol, 912 struct snd_ctl_elem_info *uinfo) 913 { 914 uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER; 915 uinfo->count = 1; 916 uinfo->value.integer.min = 0; 917 uinfo->value.integer.max = 192000; 918 uinfo->value.integer.step = 1; 919 return 0; 920 } 921 922 static int loopback_rate_get(struct snd_kcontrol *kcontrol, 923 struct snd_ctl_elem_value *ucontrol) 924 { 925 struct loopback *loopback = snd_kcontrol_chip(kcontrol); 926 927 ucontrol->value.integer.value[0] = 928 loopback->setup[kcontrol->id.subdevice] 929 [kcontrol->id.device].rate; 930 return 0; 931 } 932 933 static int loopback_channels_info(struct snd_kcontrol *kcontrol, 934 struct snd_ctl_elem_info *uinfo) 935 { 936 uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER; 937 uinfo->count = 1; 938 uinfo->value.integer.min = 1; 939 uinfo->value.integer.max = 1024; 940 uinfo->value.integer.step = 1; 941 return 0; 942 } 943 944 static int loopback_channels_get(struct snd_kcontrol *kcontrol, 945 struct snd_ctl_elem_value *ucontrol) 946 { 947 struct loopback *loopback = snd_kcontrol_chip(kcontrol); 948 949 ucontrol->value.integer.value[0] = 950 loopback->setup[kcontrol->id.subdevice] 951 [kcontrol->id.device].channels; 952 return 0; 953 } 954 955 static struct snd_kcontrol_new loopback_controls[] = { 956 { 957 .iface = SNDRV_CTL_ELEM_IFACE_PCM, 958 .name = "PCM Rate Shift 100000", 959 .info = loopback_rate_shift_info, 960 .get = loopback_rate_shift_get, 961 .put = loopback_rate_shift_put, 962 }, 963 { 964 .iface = SNDRV_CTL_ELEM_IFACE_PCM, 965 .name = "PCM Notify", 966 .info = snd_ctl_boolean_mono_info, 967 .get = loopback_notify_get, 968 .put = loopback_notify_put, 969 }, 970 #define ACTIVE_IDX 2 971 { 972 .access = SNDRV_CTL_ELEM_ACCESS_READ, 973 .iface = SNDRV_CTL_ELEM_IFACE_PCM, 974 .name = "PCM Slave Active", 975 .info = snd_ctl_boolean_mono_info, 976 .get = loopback_active_get, 977 }, 978 #define FORMAT_IDX 3 979 { 980 .access = SNDRV_CTL_ELEM_ACCESS_READ, 981 .iface = SNDRV_CTL_ELEM_IFACE_PCM, 982 .name = "PCM Slave Format", 983 .info = loopback_format_info, 984 .get = loopback_format_get 985 }, 986 #define RATE_IDX 4 987 { 988 .access = SNDRV_CTL_ELEM_ACCESS_READ, 989 .iface = SNDRV_CTL_ELEM_IFACE_PCM, 990 .name = "PCM Slave Rate", 991 .info = loopback_rate_info, 992 .get = loopback_rate_get 993 }, 994 #define CHANNELS_IDX 5 995 { 996 .access = SNDRV_CTL_ELEM_ACCESS_READ, 997 .iface = SNDRV_CTL_ELEM_IFACE_PCM, 998 .name = "PCM Slave Channels", 999 .info = loopback_channels_info, 1000 .get = loopback_channels_get 1001 } 1002 }; 1003 1004 static int loopback_mixer_new(struct loopback *loopback, int notify) 1005 { 1006 struct snd_card *card = loopback->card; 1007 struct snd_pcm *pcm; 1008 struct snd_kcontrol *kctl; 1009 struct loopback_setup *setup; 1010 int err, dev, substr, substr_count, idx; 1011 1012 strcpy(card->mixername, "Loopback Mixer"); 1013 for (dev = 0; dev < 2; dev++) { 1014 pcm = loopback->pcm[dev]; 1015 substr_count = 1016 pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream_count; 1017 for (substr = 0; substr < substr_count; substr++) { 1018 setup = &loopback->setup[substr][dev]; 1019 setup->notify = notify; 1020 setup->rate_shift = NO_PITCH; 1021 setup->format = SNDRV_PCM_FORMAT_S16_LE; 1022 setup->rate = 48000; 1023 setup->channels = 2; 1024 for (idx = 0; idx < ARRAY_SIZE(loopback_controls); 1025 idx++) { 1026 kctl = snd_ctl_new1(&loopback_controls[idx], 1027 loopback); 1028 if (!kctl) 1029 return -ENOMEM; 1030 kctl->id.device = dev; 1031 kctl->id.subdevice = substr; 1032 switch (idx) { 1033 case ACTIVE_IDX: 1034 setup->active_id = kctl->id; 1035 break; 1036 case FORMAT_IDX: 1037 setup->format_id = kctl->id; 1038 break; 1039 case RATE_IDX: 1040 setup->rate_id = kctl->id; 1041 break; 1042 case CHANNELS_IDX: 1043 setup->channels_id = kctl->id; 1044 break; 1045 default: 1046 break; 1047 } 1048 err = snd_ctl_add(card, kctl); 1049 if (err < 0) 1050 return err; 1051 } 1052 } 1053 } 1054 return 0; 1055 } 1056 1057 static void print_dpcm_info(struct snd_info_buffer *buffer, 1058 struct loopback_pcm *dpcm, 1059 const char *id) 1060 { 1061 snd_iprintf(buffer, " %s\n", id); 1062 if (dpcm == NULL) { 1063 snd_iprintf(buffer, " inactive\n"); 1064 return; 1065 } 1066 snd_iprintf(buffer, " buffer_size:\t%u\n", dpcm->pcm_buffer_size); 1067 snd_iprintf(buffer, " buffer_pos:\t\t%u\n", dpcm->buf_pos); 1068 snd_iprintf(buffer, " silent_size:\t%u\n", dpcm->silent_size); 1069 snd_iprintf(buffer, " period_size:\t%u\n", dpcm->pcm_period_size); 1070 snd_iprintf(buffer, " bytes_per_sec:\t%u\n", dpcm->pcm_bps); 1071 snd_iprintf(buffer, " sample_align:\t%u\n", dpcm->pcm_salign); 1072 snd_iprintf(buffer, " rate_shift:\t\t%u\n", dpcm->pcm_rate_shift); 1073 snd_iprintf(buffer, " update_pending:\t%u\n", 1074 dpcm->period_update_pending); 1075 snd_iprintf(buffer, " irq_pos:\t\t%u\n", dpcm->irq_pos); 1076 snd_iprintf(buffer, " period_frac:\t%u\n", dpcm->period_size_frac); 1077 snd_iprintf(buffer, " last_jiffies:\t%lu (%lu)\n", 1078 dpcm->last_jiffies, jiffies); 1079 snd_iprintf(buffer, " timer_expires:\t%lu\n", dpcm->timer.expires); 1080 } 1081 1082 static void print_substream_info(struct snd_info_buffer *buffer, 1083 struct loopback *loopback, 1084 int sub, 1085 int num) 1086 { 1087 struct loopback_cable *cable = loopback->cables[sub][num]; 1088 1089 snd_iprintf(buffer, "Cable %i substream %i:\n", num, sub); 1090 if (cable == NULL) { 1091 snd_iprintf(buffer, " inactive\n"); 1092 return; 1093 } 1094 snd_iprintf(buffer, " valid: %u\n", cable->valid); 1095 snd_iprintf(buffer, " running: %u\n", cable->running); 1096 snd_iprintf(buffer, " pause: %u\n", cable->pause); 1097 print_dpcm_info(buffer, cable->streams[0], "Playback"); 1098 print_dpcm_info(buffer, cable->streams[1], "Capture"); 1099 } 1100 1101 static void print_cable_info(struct snd_info_entry *entry, 1102 struct snd_info_buffer *buffer) 1103 { 1104 struct loopback *loopback = entry->private_data; 1105 int sub, num; 1106 1107 mutex_lock(&loopback->cable_lock); 1108 num = entry->name[strlen(entry->name)-1]; 1109 num = num == '0' ? 0 : 1; 1110 for (sub = 0; sub < MAX_PCM_SUBSTREAMS; sub++) 1111 print_substream_info(buffer, loopback, sub, num); 1112 mutex_unlock(&loopback->cable_lock); 1113 } 1114 1115 static int loopback_proc_new(struct loopback *loopback, int cidx) 1116 { 1117 char name[32]; 1118 struct snd_info_entry *entry; 1119 int err; 1120 1121 snprintf(name, sizeof(name), "cable#%d", cidx); 1122 err = snd_card_proc_new(loopback->card, name, &entry); 1123 if (err < 0) 1124 return err; 1125 1126 snd_info_set_text_ops(entry, loopback, print_cable_info); 1127 return 0; 1128 } 1129 1130 static int loopback_probe(struct platform_device *devptr) 1131 { 1132 struct snd_card *card; 1133 struct loopback *loopback; 1134 int dev = devptr->id; 1135 int err; 1136 1137 err = snd_card_new(&devptr->dev, index[dev], id[dev], THIS_MODULE, 1138 sizeof(struct loopback), &card); 1139 if (err < 0) 1140 return err; 1141 loopback = card->private_data; 1142 1143 if (pcm_substreams[dev] < 1) 1144 pcm_substreams[dev] = 1; 1145 if (pcm_substreams[dev] > MAX_PCM_SUBSTREAMS) 1146 pcm_substreams[dev] = MAX_PCM_SUBSTREAMS; 1147 1148 loopback->card = card; 1149 mutex_init(&loopback->cable_lock); 1150 1151 err = loopback_pcm_new(loopback, 0, pcm_substreams[dev]); 1152 if (err < 0) 1153 goto __nodev; 1154 err = loopback_pcm_new(loopback, 1, pcm_substreams[dev]); 1155 if (err < 0) 1156 goto __nodev; 1157 err = loopback_mixer_new(loopback, pcm_notify[dev] ? 1 : 0); 1158 if (err < 0) 1159 goto __nodev; 1160 loopback_proc_new(loopback, 0); 1161 loopback_proc_new(loopback, 1); 1162 strcpy(card->driver, "Loopback"); 1163 strcpy(card->shortname, "Loopback"); 1164 sprintf(card->longname, "Loopback %i", dev + 1); 1165 err = snd_card_register(card); 1166 if (!err) { 1167 platform_set_drvdata(devptr, card); 1168 return 0; 1169 } 1170 __nodev: 1171 snd_card_free(card); 1172 return err; 1173 } 1174 1175 static int loopback_remove(struct platform_device *devptr) 1176 { 1177 snd_card_free(platform_get_drvdata(devptr)); 1178 return 0; 1179 } 1180 1181 #ifdef CONFIG_PM_SLEEP 1182 static int loopback_suspend(struct device *pdev) 1183 { 1184 struct snd_card *card = dev_get_drvdata(pdev); 1185 struct loopback *loopback = card->private_data; 1186 1187 snd_power_change_state(card, SNDRV_CTL_POWER_D3hot); 1188 1189 snd_pcm_suspend_all(loopback->pcm[0]); 1190 snd_pcm_suspend_all(loopback->pcm[1]); 1191 return 0; 1192 } 1193 1194 static int loopback_resume(struct device *pdev) 1195 { 1196 struct snd_card *card = dev_get_drvdata(pdev); 1197 1198 snd_power_change_state(card, SNDRV_CTL_POWER_D0); 1199 return 0; 1200 } 1201 1202 static SIMPLE_DEV_PM_OPS(loopback_pm, loopback_suspend, loopback_resume); 1203 #define LOOPBACK_PM_OPS &loopback_pm 1204 #else 1205 #define LOOPBACK_PM_OPS NULL 1206 #endif 1207 1208 #define SND_LOOPBACK_DRIVER "snd_aloop" 1209 1210 static struct platform_driver loopback_driver = { 1211 .probe = loopback_probe, 1212 .remove = loopback_remove, 1213 .driver = { 1214 .name = SND_LOOPBACK_DRIVER, 1215 .pm = LOOPBACK_PM_OPS, 1216 }, 1217 }; 1218 1219 static void loopback_unregister_all(void) 1220 { 1221 int i; 1222 1223 for (i = 0; i < ARRAY_SIZE(devices); ++i) 1224 platform_device_unregister(devices[i]); 1225 platform_driver_unregister(&loopback_driver); 1226 } 1227 1228 static int __init alsa_card_loopback_init(void) 1229 { 1230 int i, err, cards; 1231 1232 err = platform_driver_register(&loopback_driver); 1233 if (err < 0) 1234 return err; 1235 1236 1237 cards = 0; 1238 for (i = 0; i < SNDRV_CARDS; i++) { 1239 struct platform_device *device; 1240 if (!enable[i]) 1241 continue; 1242 device = platform_device_register_simple(SND_LOOPBACK_DRIVER, 1243 i, NULL, 0); 1244 if (IS_ERR(device)) 1245 continue; 1246 if (!platform_get_drvdata(device)) { 1247 platform_device_unregister(device); 1248 continue; 1249 } 1250 devices[i] = device; 1251 cards++; 1252 } 1253 if (!cards) { 1254 #ifdef MODULE 1255 printk(KERN_ERR "aloop: No loopback enabled\n"); 1256 #endif 1257 loopback_unregister_all(); 1258 return -ENODEV; 1259 } 1260 return 0; 1261 } 1262 1263 static void __exit alsa_card_loopback_exit(void) 1264 { 1265 loopback_unregister_all(); 1266 } 1267 1268 module_init(alsa_card_loopback_init) 1269 module_exit(alsa_card_loopback_exit) 1270