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