1 /* 2 * Loopback soundcard 3 * 4 * Original code: 5 * Copyright (c) by Jaroslav Kysela <perex@perex.cz> 6 * 7 * More accurate positioning and full-duplex support: 8 * Copyright (c) Ahmet İnan <ainan at mathematik.uni-freiburg.de> 9 * 10 * Major (almost complete) rewrite: 11 * Copyright (c) by Takashi Iwai <tiwai@suse.de> 12 * 13 * A next major update in 2010 (separate timers for playback and capture): 14 * Copyright (c) Jaroslav Kysela <perex@perex.cz> 15 * 16 * This program is free software; you can redistribute it and/or modify 17 * it under the terms of the GNU General Public License as published by 18 * the Free Software Foundation; either version 2 of the License, or 19 * (at your option) any later version. 20 * 21 * This program is distributed in the hope that it will be useful, 22 * but WITHOUT ANY WARRANTY; without even the implied warranty of 23 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 24 * GNU General Public License for more details. 25 * 26 * You should have received a copy of the GNU General Public License 27 * along with this program; if not, write to the Free Software 28 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 29 * 30 */ 31 32 #include <linux/init.h> 33 #include <linux/jiffies.h> 34 #include <linux/slab.h> 35 #include <linux/time.h> 36 #include <linux/wait.h> 37 #include <linux/module.h> 38 #include <linux/platform_device.h> 39 #include <sound/core.h> 40 #include <sound/control.h> 41 #include <sound/pcm.h> 42 #include <sound/info.h> 43 #include <sound/initval.h> 44 45 MODULE_AUTHOR("Jaroslav Kysela <perex@perex.cz>"); 46 MODULE_DESCRIPTION("A loopback soundcard"); 47 MODULE_LICENSE("GPL"); 48 MODULE_SUPPORTED_DEVICE("{{ALSA,Loopback soundcard}}"); 49 50 #define MAX_PCM_SUBSTREAMS 8 51 52 static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX; /* Index 0-MAX */ 53 static char *id[SNDRV_CARDS] = SNDRV_DEFAULT_STR; /* ID for this card */ 54 static bool enable[SNDRV_CARDS] = {1, [1 ... (SNDRV_CARDS - 1)] = 0}; 55 static int pcm_substreams[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 8}; 56 static int pcm_notify[SNDRV_CARDS]; 57 58 module_param_array(index, int, NULL, 0444); 59 MODULE_PARM_DESC(index, "Index value for loopback soundcard."); 60 module_param_array(id, charp, NULL, 0444); 61 MODULE_PARM_DESC(id, "ID string for loopback soundcard."); 62 module_param_array(enable, bool, NULL, 0444); 63 MODULE_PARM_DESC(enable, "Enable this loopback soundcard."); 64 module_param_array(pcm_substreams, int, NULL, 0444); 65 MODULE_PARM_DESC(pcm_substreams, "PCM substreams # (1-8) for loopback driver."); 66 module_param_array(pcm_notify, int, NULL, 0444); 67 MODULE_PARM_DESC(pcm_notify, "Break capture when PCM format/rate/channels changes."); 68 69 #define NO_PITCH 100000 70 71 struct loopback_pcm; 72 73 struct loopback_cable { 74 spinlock_t lock; 75 struct loopback_pcm *streams[2]; 76 struct snd_pcm_hardware hw; 77 /* flags */ 78 unsigned int valid; 79 unsigned int running; 80 unsigned int pause; 81 }; 82 83 struct loopback_setup { 84 unsigned int notify: 1; 85 unsigned int rate_shift; 86 unsigned int format; 87 unsigned int rate; 88 unsigned int channels; 89 struct snd_ctl_elem_id active_id; 90 struct snd_ctl_elem_id format_id; 91 struct snd_ctl_elem_id rate_id; 92 struct snd_ctl_elem_id channels_id; 93 }; 94 95 struct loopback { 96 struct snd_card *card; 97 struct mutex cable_lock; 98 struct loopback_cable *cables[MAX_PCM_SUBSTREAMS][2]; 99 struct snd_pcm *pcm[2]; 100 struct loopback_setup setup[MAX_PCM_SUBSTREAMS][2]; 101 }; 102 103 struct loopback_pcm { 104 struct loopback *loopback; 105 struct snd_pcm_substream *substream; 106 struct loopback_cable *cable; 107 unsigned int pcm_buffer_size; 108 unsigned int buf_pos; /* position in buffer */ 109 unsigned int silent_size; 110 /* PCM parameters */ 111 unsigned int pcm_period_size; 112 unsigned int pcm_bps; /* bytes per second */ 113 unsigned int pcm_salign; /* bytes per sample * channels */ 114 unsigned int pcm_rate_shift; /* rate shift value */ 115 /* flags */ 116 unsigned int period_update_pending :1; 117 /* timer stuff */ 118 unsigned int irq_pos; /* fractional IRQ position */ 119 unsigned int period_size_frac; 120 unsigned int last_drift; 121 unsigned long last_jiffies; 122 struct timer_list timer; 123 }; 124 125 static struct platform_device *devices[SNDRV_CARDS]; 126 127 static inline unsigned int byte_pos(struct loopback_pcm *dpcm, unsigned int x) 128 { 129 if (dpcm->pcm_rate_shift == NO_PITCH) { 130 x /= HZ; 131 } else { 132 x = div_u64(NO_PITCH * (unsigned long long)x, 133 HZ * (unsigned long long)dpcm->pcm_rate_shift); 134 } 135 return x - (x % dpcm->pcm_salign); 136 } 137 138 static inline unsigned int frac_pos(struct loopback_pcm *dpcm, unsigned int x) 139 { 140 if (dpcm->pcm_rate_shift == NO_PITCH) { /* no pitch */ 141 return x * HZ; 142 } else { 143 x = div_u64(dpcm->pcm_rate_shift * (unsigned long long)x * HZ, 144 NO_PITCH); 145 } 146 return x; 147 } 148 149 static inline struct loopback_setup *get_setup(struct loopback_pcm *dpcm) 150 { 151 int device = dpcm->substream->pstr->pcm->device; 152 153 if (dpcm->substream->stream == SNDRV_PCM_STREAM_PLAYBACK) 154 device ^= 1; 155 return &dpcm->loopback->setup[dpcm->substream->number][device]; 156 } 157 158 static inline unsigned int get_notify(struct loopback_pcm *dpcm) 159 { 160 return get_setup(dpcm)->notify; 161 } 162 163 static inline unsigned int get_rate_shift(struct loopback_pcm *dpcm) 164 { 165 return get_setup(dpcm)->rate_shift; 166 } 167 168 /* call in cable->lock */ 169 static void loopback_timer_start(struct loopback_pcm *dpcm) 170 { 171 unsigned long tick; 172 unsigned int rate_shift = get_rate_shift(dpcm); 173 174 if (rate_shift != dpcm->pcm_rate_shift) { 175 dpcm->pcm_rate_shift = rate_shift; 176 dpcm->period_size_frac = frac_pos(dpcm, dpcm->pcm_period_size); 177 } 178 if (dpcm->period_size_frac <= dpcm->irq_pos) { 179 dpcm->irq_pos %= dpcm->period_size_frac; 180 dpcm->period_update_pending = 1; 181 } 182 tick = dpcm->period_size_frac - dpcm->irq_pos; 183 tick = (tick + dpcm->pcm_bps - 1) / dpcm->pcm_bps; 184 dpcm->timer.expires = jiffies + tick; 185 add_timer(&dpcm->timer); 186 } 187 188 /* call in cable->lock */ 189 static inline void loopback_timer_stop(struct loopback_pcm *dpcm) 190 { 191 del_timer(&dpcm->timer); 192 dpcm->timer.expires = 0; 193 } 194 195 #define CABLE_VALID_PLAYBACK (1 << SNDRV_PCM_STREAM_PLAYBACK) 196 #define CABLE_VALID_CAPTURE (1 << SNDRV_PCM_STREAM_CAPTURE) 197 #define CABLE_VALID_BOTH (CABLE_VALID_PLAYBACK|CABLE_VALID_CAPTURE) 198 199 static int loopback_check_format(struct loopback_cable *cable, int stream) 200 { 201 struct snd_pcm_runtime *runtime, *cruntime; 202 struct loopback_setup *setup; 203 struct snd_card *card; 204 int check; 205 206 if (cable->valid != CABLE_VALID_BOTH) { 207 if (stream == SNDRV_PCM_STREAM_PLAYBACK) 208 goto __notify; 209 return 0; 210 } 211 runtime = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]-> 212 substream->runtime; 213 cruntime = cable->streams[SNDRV_PCM_STREAM_CAPTURE]-> 214 substream->runtime; 215 check = runtime->format != cruntime->format || 216 runtime->rate != cruntime->rate || 217 runtime->channels != cruntime->channels; 218 if (!check) 219 return 0; 220 if (stream == SNDRV_PCM_STREAM_CAPTURE) { 221 return -EIO; 222 } else { 223 snd_pcm_stop(cable->streams[SNDRV_PCM_STREAM_CAPTURE]-> 224 substream, SNDRV_PCM_STATE_DRAINING); 225 __notify: 226 runtime = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]-> 227 substream->runtime; 228 setup = get_setup(cable->streams[SNDRV_PCM_STREAM_PLAYBACK]); 229 card = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]->loopback->card; 230 if (setup->format != runtime->format) { 231 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE, 232 &setup->format_id); 233 setup->format = runtime->format; 234 } 235 if (setup->rate != runtime->rate) { 236 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE, 237 &setup->rate_id); 238 setup->rate = runtime->rate; 239 } 240 if (setup->channels != runtime->channels) { 241 snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_VALUE, 242 &setup->channels_id); 243 setup->channels = runtime->channels; 244 } 245 } 246 return 0; 247 } 248 249 static void loopback_active_notify(struct loopback_pcm *dpcm) 250 { 251 snd_ctl_notify(dpcm->loopback->card, 252 SNDRV_CTL_EVENT_MASK_VALUE, 253 &get_setup(dpcm)->active_id); 254 } 255 256 static int loopback_trigger(struct snd_pcm_substream *substream, int cmd) 257 { 258 struct snd_pcm_runtime *runtime = substream->runtime; 259 struct loopback_pcm *dpcm = runtime->private_data; 260 struct loopback_cable *cable = dpcm->cable; 261 int err, stream = 1 << substream->stream; 262 263 switch (cmd) { 264 case SNDRV_PCM_TRIGGER_START: 265 err = loopback_check_format(cable, substream->stream); 266 if (err < 0) 267 return err; 268 dpcm->last_jiffies = jiffies; 269 dpcm->pcm_rate_shift = 0; 270 dpcm->last_drift = 0; 271 spin_lock(&cable->lock); 272 cable->running |= stream; 273 cable->pause &= ~stream; 274 loopback_timer_start(dpcm); 275 spin_unlock(&cable->lock); 276 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) 277 loopback_active_notify(dpcm); 278 break; 279 case SNDRV_PCM_TRIGGER_STOP: 280 spin_lock(&cable->lock); 281 cable->running &= ~stream; 282 cable->pause &= ~stream; 283 loopback_timer_stop(dpcm); 284 spin_unlock(&cable->lock); 285 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) 286 loopback_active_notify(dpcm); 287 break; 288 case SNDRV_PCM_TRIGGER_PAUSE_PUSH: 289 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_substream(struct loopback_pcm *dpcm, 310 struct snd_pcm_runtime *runtime) 311 { 312 struct snd_pcm_runtime *dst_runtime; 313 314 if (dpcm == NULL || dpcm->substream == NULL) 315 return; 316 dst_runtime = dpcm->substream->runtime; 317 if (dst_runtime == NULL) 318 return; 319 dst_runtime->hw = dpcm->cable->hw; 320 } 321 322 static void params_change(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; 327 328 cable->hw.formats = pcm_format_to_bits(runtime->format); 329 cable->hw.rate_min = runtime->rate; 330 cable->hw.rate_max = runtime->rate; 331 cable->hw.channels_min = runtime->channels; 332 cable->hw.channels_max = runtime->channels; 333 params_change_substream(cable->streams[SNDRV_PCM_STREAM_PLAYBACK], 334 runtime); 335 params_change_substream(cable->streams[SNDRV_PCM_STREAM_CAPTURE], 336 runtime); 337 } 338 339 static int loopback_prepare(struct snd_pcm_substream *substream) 340 { 341 struct snd_pcm_runtime *runtime = substream->runtime; 342 struct loopback_pcm *dpcm = runtime->private_data; 343 struct loopback_cable *cable = dpcm->cable; 344 int bps, salign; 345 346 salign = (snd_pcm_format_width(runtime->format) * 347 runtime->channels) / 8; 348 bps = salign * runtime->rate; 349 if (bps <= 0 || salign <= 0) 350 return -EINVAL; 351 352 dpcm->buf_pos = 0; 353 dpcm->pcm_buffer_size = frames_to_bytes(runtime, runtime->buffer_size); 354 if (substream->stream == SNDRV_PCM_STREAM_CAPTURE) { 355 /* clear capture buffer */ 356 dpcm->silent_size = dpcm->pcm_buffer_size; 357 snd_pcm_format_set_silence(runtime->format, runtime->dma_area, 358 runtime->buffer_size * runtime->channels); 359 } 360 361 dpcm->irq_pos = 0; 362 dpcm->period_update_pending = 0; 363 dpcm->pcm_bps = bps; 364 dpcm->pcm_salign = salign; 365 dpcm->pcm_period_size = frames_to_bytes(runtime, runtime->period_size); 366 367 mutex_lock(&dpcm->loopback->cable_lock); 368 if (!(cable->valid & ~(1 << substream->stream)) || 369 (get_setup(dpcm)->notify && 370 substream->stream == SNDRV_PCM_STREAM_PLAYBACK)) 371 params_change(substream); 372 cable->valid |= 1 << substream->stream; 373 mutex_unlock(&dpcm->loopback->cable_lock); 374 375 return 0; 376 } 377 378 static void clear_capture_buf(struct loopback_pcm *dpcm, unsigned int bytes) 379 { 380 struct snd_pcm_runtime *runtime = dpcm->substream->runtime; 381 char *dst = runtime->dma_area; 382 unsigned int dst_off = dpcm->buf_pos; 383 384 if (dpcm->silent_size >= dpcm->pcm_buffer_size) 385 return; 386 if (dpcm->silent_size + bytes > dpcm->pcm_buffer_size) 387 bytes = dpcm->pcm_buffer_size - dpcm->silent_size; 388 389 for (;;) { 390 unsigned int size = bytes; 391 if (dst_off + size > dpcm->pcm_buffer_size) 392 size = dpcm->pcm_buffer_size - dst_off; 393 snd_pcm_format_set_silence(runtime->format, dst + dst_off, 394 bytes_to_frames(runtime, size) * 395 runtime->channels); 396 dpcm->silent_size += size; 397 bytes -= size; 398 if (!bytes) 399 break; 400 dst_off = 0; 401 } 402 } 403 404 static void copy_play_buf(struct loopback_pcm *play, 405 struct loopback_pcm *capt, 406 unsigned int bytes) 407 { 408 struct snd_pcm_runtime *runtime = play->substream->runtime; 409 char *src = runtime->dma_area; 410 char *dst = capt->substream->runtime->dma_area; 411 unsigned int src_off = play->buf_pos; 412 unsigned int dst_off = capt->buf_pos; 413 unsigned int clear_bytes = 0; 414 415 /* check if playback is draining, trim the capture copy size 416 * when our pointer is at the end of playback ring buffer */ 417 if (runtime->status->state == SNDRV_PCM_STATE_DRAINING && 418 snd_pcm_playback_hw_avail(runtime) < runtime->buffer_size) { 419 snd_pcm_uframes_t appl_ptr, appl_ptr1, diff; 420 appl_ptr = appl_ptr1 = runtime->control->appl_ptr; 421 appl_ptr1 -= appl_ptr1 % runtime->buffer_size; 422 appl_ptr1 += play->buf_pos / play->pcm_salign; 423 if (appl_ptr < appl_ptr1) 424 appl_ptr1 -= runtime->buffer_size; 425 diff = (appl_ptr - appl_ptr1) * play->pcm_salign; 426 if (diff < bytes) { 427 clear_bytes = bytes - diff; 428 bytes = diff; 429 } 430 } 431 432 for (;;) { 433 unsigned int size = bytes; 434 if (src_off + size > play->pcm_buffer_size) 435 size = play->pcm_buffer_size - src_off; 436 if (dst_off + size > capt->pcm_buffer_size) 437 size = capt->pcm_buffer_size - dst_off; 438 memcpy(dst + dst_off, src + src_off, size); 439 capt->silent_size = 0; 440 bytes -= size; 441 if (!bytes) 442 break; 443 src_off = (src_off + size) % play->pcm_buffer_size; 444 dst_off = (dst_off + size) % capt->pcm_buffer_size; 445 } 446 447 if (clear_bytes > 0) { 448 clear_capture_buf(capt, clear_bytes); 449 capt->silent_size = 0; 450 } 451 } 452 453 static inline unsigned int bytepos_delta(struct loopback_pcm *dpcm, 454 unsigned int jiffies_delta) 455 { 456 unsigned long last_pos; 457 unsigned int delta; 458 459 last_pos = byte_pos(dpcm, dpcm->irq_pos); 460 dpcm->irq_pos += jiffies_delta * dpcm->pcm_bps; 461 delta = byte_pos(dpcm, dpcm->irq_pos) - last_pos; 462 if (delta >= dpcm->last_drift) 463 delta -= dpcm->last_drift; 464 dpcm->last_drift = 0; 465 if (dpcm->irq_pos >= dpcm->period_size_frac) { 466 dpcm->irq_pos %= dpcm->period_size_frac; 467 dpcm->period_update_pending = 1; 468 } 469 return delta; 470 } 471 472 static inline void bytepos_finish(struct loopback_pcm *dpcm, 473 unsigned int delta) 474 { 475 dpcm->buf_pos += delta; 476 dpcm->buf_pos %= dpcm->pcm_buffer_size; 477 } 478 479 /* call in cable->lock */ 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; 488 489 running = cable->running ^ cable->pause; 490 if (running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) { 491 delta_play = jiffies - dpcm_play->last_jiffies; 492 dpcm_play->last_jiffies += delta_play; 493 } 494 495 if (running & (1 << SNDRV_PCM_STREAM_CAPTURE)) { 496 delta_capt = jiffies - dpcm_capt->last_jiffies; 497 dpcm_capt->last_jiffies += delta_capt; 498 } 499 500 if (delta_play == 0 && delta_capt == 0) 501 goto unlock; 502 503 if (delta_play > delta_capt) { 504 count1 = bytepos_delta(dpcm_play, delta_play - delta_capt); 505 bytepos_finish(dpcm_play, count1); 506 delta_play = delta_capt; 507 } else if (delta_play < delta_capt) { 508 count1 = bytepos_delta(dpcm_capt, delta_capt - delta_play); 509 clear_capture_buf(dpcm_capt, count1); 510 bytepos_finish(dpcm_capt, count1); 511 delta_capt = delta_play; 512 } 513 514 if (delta_play == 0 && delta_capt == 0) 515 goto unlock; 516 517 /* note delta_capt == delta_play at this moment */ 518 count1 = bytepos_delta(dpcm_play, delta_play); 519 count2 = bytepos_delta(dpcm_capt, delta_capt); 520 if (count1 < count2) { 521 dpcm_capt->last_drift = count2 - count1; 522 count1 = count2; 523 } else if (count1 > count2) { 524 dpcm_play->last_drift = count1 - count2; 525 } 526 copy_play_buf(dpcm_play, dpcm_capt, count1); 527 bytepos_finish(dpcm_play, count1); 528 bytepos_finish(dpcm_capt, count1); 529 unlock: 530 return running; 531 } 532 533 static void loopback_timer_function(unsigned long data) 534 { 535 struct loopback_pcm *dpcm = (struct loopback_pcm *)data; 536 unsigned long flags; 537 538 spin_lock_irqsave(&dpcm->cable->lock, flags); 539 if (loopback_pos_update(dpcm->cable) & (1 << dpcm->substream->stream)) { 540 loopback_timer_start(dpcm); 541 if (dpcm->period_update_pending) { 542 dpcm->period_update_pending = 0; 543 spin_unlock_irqrestore(&dpcm->cable->lock, flags); 544 /* need to unlock before calling below */ 545 snd_pcm_period_elapsed(dpcm->substream); 546 return; 547 } 548 } 549 spin_unlock_irqrestore(&dpcm->cable->lock, flags); 550 } 551 552 static snd_pcm_uframes_t loopback_pointer(struct snd_pcm_substream *substream) 553 { 554 struct snd_pcm_runtime *runtime = substream->runtime; 555 struct loopback_pcm *dpcm = runtime->private_data; 556 snd_pcm_uframes_t pos; 557 558 spin_lock(&dpcm->cable->lock); 559 loopback_pos_update(dpcm->cable); 560 pos = dpcm->buf_pos; 561 spin_unlock(&dpcm->cable->lock); 562 return bytes_to_frames(runtime, pos); 563 } 564 565 static struct snd_pcm_hardware loopback_pcm_hardware = 566 { 567 .info = (SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_MMAP | 568 SNDRV_PCM_INFO_MMAP_VALID | SNDRV_PCM_INFO_PAUSE | 569 SNDRV_PCM_INFO_RESUME), 570 .formats = (SNDRV_PCM_FMTBIT_S16_LE | SNDRV_PCM_FMTBIT_S16_BE | 571 SNDRV_PCM_FMTBIT_S32_LE | SNDRV_PCM_FMTBIT_S32_BE | 572 SNDRV_PCM_FMTBIT_FLOAT_LE | SNDRV_PCM_FMTBIT_FLOAT_BE), 573 .rates = SNDRV_PCM_RATE_CONTINUOUS | SNDRV_PCM_RATE_8000_192000, 574 .rate_min = 8000, 575 .rate_max = 192000, 576 .channels_min = 1, 577 .channels_max = 32, 578 .buffer_bytes_max = 2 * 1024 * 1024, 579 .period_bytes_min = 64, 580 /* note check overflow in frac_pos() using pcm_rate_shift before 581 changing period_bytes_max value */ 582 .period_bytes_max = 1024 * 1024, 583 .periods_min = 1, 584 .periods_max = 1024, 585 .fifo_size = 0, 586 }; 587 588 static void loopback_runtime_free(struct snd_pcm_runtime *runtime) 589 { 590 struct loopback_pcm *dpcm = runtime->private_data; 591 kfree(dpcm); 592 } 593 594 static int loopback_hw_params(struct snd_pcm_substream *substream, 595 struct snd_pcm_hw_params *params) 596 { 597 return snd_pcm_lib_alloc_vmalloc_buffer(substream, 598 params_buffer_bytes(params)); 599 } 600 601 static int loopback_hw_free(struct snd_pcm_substream *substream) 602 { 603 struct snd_pcm_runtime *runtime = substream->runtime; 604 struct loopback_pcm *dpcm = runtime->private_data; 605 struct loopback_cable *cable = dpcm->cable; 606 607 mutex_lock(&dpcm->loopback->cable_lock); 608 cable->valid &= ~(1 << substream->stream); 609 mutex_unlock(&dpcm->loopback->cable_lock); 610 return snd_pcm_lib_free_vmalloc_buffer(substream); 611 } 612 613 static unsigned int get_cable_index(struct snd_pcm_substream *substream) 614 { 615 if (!substream->pcm->device) 616 return substream->stream; 617 else 618 return !substream->stream; 619 } 620 621 static int rule_format(struct snd_pcm_hw_params *params, 622 struct snd_pcm_hw_rule *rule) 623 { 624 625 struct snd_pcm_hardware *hw = rule->private; 626 struct snd_mask *maskp = hw_param_mask(params, rule->var); 627 628 maskp->bits[0] &= (u_int32_t)hw->formats; 629 maskp->bits[1] &= (u_int32_t)(hw->formats >> 32); 630 memset(maskp->bits + 2, 0, (SNDRV_MASK_MAX-64) / 8); /* clear rest */ 631 if (! maskp->bits[0] && ! maskp->bits[1]) 632 return -EINVAL; 633 return 0; 634 } 635 636 static int rule_rate(struct snd_pcm_hw_params *params, 637 struct snd_pcm_hw_rule *rule) 638 { 639 struct snd_pcm_hardware *hw = rule->private; 640 struct snd_interval t; 641 642 t.min = hw->rate_min; 643 t.max = hw->rate_max; 644 t.openmin = t.openmax = 0; 645 t.integer = 0; 646 return snd_interval_refine(hw_param_interval(params, rule->var), &t); 647 } 648 649 static int rule_channels(struct snd_pcm_hw_params *params, 650 struct snd_pcm_hw_rule *rule) 651 { 652 struct snd_pcm_hardware *hw = rule->private; 653 struct snd_interval t; 654 655 t.min = hw->channels_min; 656 t.max = hw->channels_max; 657 t.openmin = t.openmax = 0; 658 t.integer = 0; 659 return snd_interval_refine(hw_param_interval(params, rule->var), &t); 660 } 661 662 static int loopback_open(struct snd_pcm_substream *substream) 663 { 664 struct snd_pcm_runtime *runtime = substream->runtime; 665 struct loopback *loopback = substream->private_data; 666 struct loopback_pcm *dpcm; 667 struct loopback_cable *cable; 668 int err = 0; 669 int dev = get_cable_index(substream); 670 671 mutex_lock(&loopback->cable_lock); 672 dpcm = kzalloc(sizeof(*dpcm), GFP_KERNEL); 673 if (!dpcm) { 674 err = -ENOMEM; 675 goto unlock; 676 } 677 dpcm->loopback = loopback; 678 dpcm->substream = substream; 679 setup_timer(&dpcm->timer, loopback_timer_function, 680 (unsigned long)dpcm); 681 682 cable = loopback->cables[substream->number][dev]; 683 if (!cable) { 684 cable = kzalloc(sizeof(*cable), GFP_KERNEL); 685 if (!cable) { 686 kfree(dpcm); 687 err = -ENOMEM; 688 goto unlock; 689 } 690 spin_lock_init(&cable->lock); 691 cable->hw = loopback_pcm_hardware; 692 loopback->cables[substream->number][dev] = cable; 693 } 694 dpcm->cable = cable; 695 cable->streams[substream->stream] = dpcm; 696 697 snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS); 698 699 /* use dynamic rules based on actual runtime->hw values */ 700 /* note that the default rules created in the PCM midlevel code */ 701 /* are cached -> they do not reflect the actual state */ 702 err = snd_pcm_hw_rule_add(runtime, 0, 703 SNDRV_PCM_HW_PARAM_FORMAT, 704 rule_format, &runtime->hw, 705 SNDRV_PCM_HW_PARAM_FORMAT, -1); 706 if (err < 0) 707 goto unlock; 708 err = snd_pcm_hw_rule_add(runtime, 0, 709 SNDRV_PCM_HW_PARAM_RATE, 710 rule_rate, &runtime->hw, 711 SNDRV_PCM_HW_PARAM_RATE, -1); 712 if (err < 0) 713 goto unlock; 714 err = snd_pcm_hw_rule_add(runtime, 0, 715 SNDRV_PCM_HW_PARAM_CHANNELS, 716 rule_channels, &runtime->hw, 717 SNDRV_PCM_HW_PARAM_CHANNELS, -1); 718 if (err < 0) 719 goto unlock; 720 721 runtime->private_data = dpcm; 722 runtime->private_free = loopback_runtime_free; 723 if (get_notify(dpcm)) 724 runtime->hw = loopback_pcm_hardware; 725 else 726 runtime->hw = cable->hw; 727 unlock: 728 mutex_unlock(&loopback->cable_lock); 729 return err; 730 } 731 732 static int loopback_close(struct snd_pcm_substream *substream) 733 { 734 struct loopback *loopback = substream->private_data; 735 struct loopback_pcm *dpcm = substream->runtime->private_data; 736 struct loopback_cable *cable; 737 int dev = get_cable_index(substream); 738 739 loopback_timer_stop(dpcm); 740 mutex_lock(&loopback->cable_lock); 741 cable = loopback->cables[substream->number][dev]; 742 if (cable->streams[!substream->stream]) { 743 /* other stream is still alive */ 744 cable->streams[substream->stream] = NULL; 745 } else { 746 /* free the cable */ 747 loopback->cables[substream->number][dev] = NULL; 748 kfree(cable); 749 } 750 mutex_unlock(&loopback->cable_lock); 751 return 0; 752 } 753 754 static 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 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 #ifdef CONFIG_PROC_FS 1058 1059 static void print_dpcm_info(struct snd_info_buffer *buffer, 1060 struct loopback_pcm *dpcm, 1061 const char *id) 1062 { 1063 snd_iprintf(buffer, " %s\n", id); 1064 if (dpcm == NULL) { 1065 snd_iprintf(buffer, " inactive\n"); 1066 return; 1067 } 1068 snd_iprintf(buffer, " buffer_size:\t%u\n", dpcm->pcm_buffer_size); 1069 snd_iprintf(buffer, " buffer_pos:\t\t%u\n", dpcm->buf_pos); 1070 snd_iprintf(buffer, " silent_size:\t%u\n", dpcm->silent_size); 1071 snd_iprintf(buffer, " period_size:\t%u\n", dpcm->pcm_period_size); 1072 snd_iprintf(buffer, " bytes_per_sec:\t%u\n", dpcm->pcm_bps); 1073 snd_iprintf(buffer, " sample_align:\t%u\n", dpcm->pcm_salign); 1074 snd_iprintf(buffer, " rate_shift:\t\t%u\n", dpcm->pcm_rate_shift); 1075 snd_iprintf(buffer, " update_pending:\t%u\n", 1076 dpcm->period_update_pending); 1077 snd_iprintf(buffer, " irq_pos:\t\t%u\n", dpcm->irq_pos); 1078 snd_iprintf(buffer, " period_frac:\t%u\n", dpcm->period_size_frac); 1079 snd_iprintf(buffer, " last_jiffies:\t%lu (%lu)\n", 1080 dpcm->last_jiffies, jiffies); 1081 snd_iprintf(buffer, " timer_expires:\t%lu\n", dpcm->timer.expires); 1082 } 1083 1084 static void print_substream_info(struct snd_info_buffer *buffer, 1085 struct loopback *loopback, 1086 int sub, 1087 int num) 1088 { 1089 struct loopback_cable *cable = loopback->cables[sub][num]; 1090 1091 snd_iprintf(buffer, "Cable %i substream %i:\n", num, sub); 1092 if (cable == NULL) { 1093 snd_iprintf(buffer, " inactive\n"); 1094 return; 1095 } 1096 snd_iprintf(buffer, " valid: %u\n", cable->valid); 1097 snd_iprintf(buffer, " running: %u\n", cable->running); 1098 snd_iprintf(buffer, " pause: %u\n", cable->pause); 1099 print_dpcm_info(buffer, cable->streams[0], "Playback"); 1100 print_dpcm_info(buffer, cable->streams[1], "Capture"); 1101 } 1102 1103 static void print_cable_info(struct snd_info_entry *entry, 1104 struct snd_info_buffer *buffer) 1105 { 1106 struct loopback *loopback = entry->private_data; 1107 int sub, num; 1108 1109 mutex_lock(&loopback->cable_lock); 1110 num = entry->name[strlen(entry->name)-1]; 1111 num = num == '0' ? 0 : 1; 1112 for (sub = 0; sub < MAX_PCM_SUBSTREAMS; sub++) 1113 print_substream_info(buffer, loopback, sub, num); 1114 mutex_unlock(&loopback->cable_lock); 1115 } 1116 1117 static int loopback_proc_new(struct loopback *loopback, int cidx) 1118 { 1119 char name[32]; 1120 struct snd_info_entry *entry; 1121 int err; 1122 1123 snprintf(name, sizeof(name), "cable#%d", cidx); 1124 err = snd_card_proc_new(loopback->card, name, &entry); 1125 if (err < 0) 1126 return err; 1127 1128 snd_info_set_text_ops(entry, loopback, print_cable_info); 1129 return 0; 1130 } 1131 1132 #else /* !CONFIG_PROC_FS */ 1133 1134 #define loopback_proc_new(loopback, cidx) do { } while (0) 1135 1136 #endif 1137 1138 static int loopback_probe(struct platform_device *devptr) 1139 { 1140 struct snd_card *card; 1141 struct loopback *loopback; 1142 int dev = devptr->id; 1143 int err; 1144 1145 err = snd_card_create(index[dev], id[dev], THIS_MODULE, 1146 sizeof(struct loopback), &card); 1147 if (err < 0) 1148 return err; 1149 loopback = card->private_data; 1150 1151 if (pcm_substreams[dev] < 1) 1152 pcm_substreams[dev] = 1; 1153 if (pcm_substreams[dev] > MAX_PCM_SUBSTREAMS) 1154 pcm_substreams[dev] = MAX_PCM_SUBSTREAMS; 1155 1156 loopback->card = card; 1157 mutex_init(&loopback->cable_lock); 1158 1159 err = loopback_pcm_new(loopback, 0, pcm_substreams[dev]); 1160 if (err < 0) 1161 goto __nodev; 1162 err = loopback_pcm_new(loopback, 1, pcm_substreams[dev]); 1163 if (err < 0) 1164 goto __nodev; 1165 err = loopback_mixer_new(loopback, pcm_notify[dev] ? 1 : 0); 1166 if (err < 0) 1167 goto __nodev; 1168 loopback_proc_new(loopback, 0); 1169 loopback_proc_new(loopback, 1); 1170 strcpy(card->driver, "Loopback"); 1171 strcpy(card->shortname, "Loopback"); 1172 sprintf(card->longname, "Loopback %i", dev + 1); 1173 err = snd_card_register(card); 1174 if (!err) { 1175 platform_set_drvdata(devptr, card); 1176 return 0; 1177 } 1178 __nodev: 1179 snd_card_free(card); 1180 return err; 1181 } 1182 1183 static int loopback_remove(struct platform_device *devptr) 1184 { 1185 snd_card_free(platform_get_drvdata(devptr)); 1186 platform_set_drvdata(devptr, NULL); 1187 return 0; 1188 } 1189 1190 #ifdef CONFIG_PM_SLEEP 1191 static int loopback_suspend(struct device *pdev) 1192 { 1193 struct snd_card *card = dev_get_drvdata(pdev); 1194 struct loopback *loopback = card->private_data; 1195 1196 snd_power_change_state(card, SNDRV_CTL_POWER_D3hot); 1197 1198 snd_pcm_suspend_all(loopback->pcm[0]); 1199 snd_pcm_suspend_all(loopback->pcm[1]); 1200 return 0; 1201 } 1202 1203 static int loopback_resume(struct device *pdev) 1204 { 1205 struct snd_card *card = dev_get_drvdata(pdev); 1206 1207 snd_power_change_state(card, SNDRV_CTL_POWER_D0); 1208 return 0; 1209 } 1210 1211 static SIMPLE_DEV_PM_OPS(loopback_pm, loopback_suspend, loopback_resume); 1212 #define LOOPBACK_PM_OPS &loopback_pm 1213 #else 1214 #define LOOPBACK_PM_OPS NULL 1215 #endif 1216 1217 #define SND_LOOPBACK_DRIVER "snd_aloop" 1218 1219 static struct platform_driver loopback_driver = { 1220 .probe = loopback_probe, 1221 .remove = loopback_remove, 1222 .driver = { 1223 .name = SND_LOOPBACK_DRIVER, 1224 .owner = THIS_MODULE, 1225 .pm = LOOPBACK_PM_OPS, 1226 }, 1227 }; 1228 1229 static void loopback_unregister_all(void) 1230 { 1231 int i; 1232 1233 for (i = 0; i < ARRAY_SIZE(devices); ++i) 1234 platform_device_unregister(devices[i]); 1235 platform_driver_unregister(&loopback_driver); 1236 } 1237 1238 static int __init alsa_card_loopback_init(void) 1239 { 1240 int i, err, cards; 1241 1242 err = platform_driver_register(&loopback_driver); 1243 if (err < 0) 1244 return err; 1245 1246 1247 cards = 0; 1248 for (i = 0; i < SNDRV_CARDS; i++) { 1249 struct platform_device *device; 1250 if (!enable[i]) 1251 continue; 1252 device = platform_device_register_simple(SND_LOOPBACK_DRIVER, 1253 i, NULL, 0); 1254 if (IS_ERR(device)) 1255 continue; 1256 if (!platform_get_drvdata(device)) { 1257 platform_device_unregister(device); 1258 continue; 1259 } 1260 devices[i] = device; 1261 cards++; 1262 } 1263 if (!cards) { 1264 #ifdef MODULE 1265 printk(KERN_ERR "aloop: No loopback enabled\n"); 1266 #endif 1267 loopback_unregister_all(); 1268 return -ENODEV; 1269 } 1270 return 0; 1271 } 1272 1273 static void __exit alsa_card_loopback_exit(void) 1274 { 1275 loopback_unregister_all(); 1276 } 1277 1278 module_init(alsa_card_loopback_init) 1279 module_exit(alsa_card_loopback_exit) 1280