1 /* 2 * Apple iSight audio driver 3 * 4 * Copyright (c) Clemens Ladisch <clemens@ladisch.de> 5 * Licensed under the terms of the GNU General Public License, version 2. 6 */ 7 8 #include <asm/byteorder.h> 9 #include <linux/delay.h> 10 #include <linux/device.h> 11 #include <linux/firewire.h> 12 #include <linux/firewire-constants.h> 13 #include <linux/module.h> 14 #include <linux/mod_devicetable.h> 15 #include <linux/mutex.h> 16 #include <linux/string.h> 17 #include <sound/control.h> 18 #include <sound/core.h> 19 #include <sound/initval.h> 20 #include <sound/pcm.h> 21 #include <sound/tlv.h> 22 #include "lib.h" 23 #include "iso-resources.h" 24 #include "packets-buffer.h" 25 26 #define OUI_APPLE 0x000a27 27 #define MODEL_APPLE_ISIGHT 0x000008 28 #define SW_ISIGHT_AUDIO 0x000010 29 30 #define REG_AUDIO_ENABLE 0x000 31 #define AUDIO_ENABLE 0x80000000 32 #define REG_DEF_AUDIO_GAIN 0x204 33 #define REG_GAIN_RAW_START 0x210 34 #define REG_GAIN_RAW_END 0x214 35 #define REG_GAIN_DB_START 0x218 36 #define REG_GAIN_DB_END 0x21c 37 #define REG_SAMPLE_RATE_INQUIRY 0x280 38 #define REG_ISO_TX_CONFIG 0x300 39 #define SPEED_SHIFT 16 40 #define REG_SAMPLE_RATE 0x400 41 #define RATE_48000 0x80000000 42 #define REG_GAIN 0x500 43 #define REG_MUTE 0x504 44 45 #define MAX_FRAMES_PER_PACKET 475 46 47 #define QUEUE_LENGTH 20 48 49 struct isight { 50 struct snd_card *card; 51 struct fw_unit *unit; 52 struct fw_device *device; 53 u64 audio_base; 54 struct snd_pcm_substream *pcm; 55 struct mutex mutex; 56 struct iso_packets_buffer buffer; 57 struct fw_iso_resources resources; 58 struct fw_iso_context *context; 59 bool pcm_active; 60 bool pcm_running; 61 bool first_packet; 62 int packet_index; 63 u32 total_samples; 64 unsigned int buffer_pointer; 65 unsigned int period_counter; 66 s32 gain_min, gain_max; 67 unsigned int gain_tlv[4]; 68 }; 69 70 struct audio_payload { 71 __be32 sample_count; 72 __be32 signature; 73 __be32 sample_total; 74 __be32 reserved; 75 __be16 samples[2 * MAX_FRAMES_PER_PACKET]; 76 }; 77 78 MODULE_DESCRIPTION("iSight audio driver"); 79 MODULE_AUTHOR("Clemens Ladisch <clemens@ladisch.de>"); 80 MODULE_LICENSE("GPL v2"); 81 82 static struct fw_iso_packet audio_packet = { 83 .payload_length = sizeof(struct audio_payload), 84 .interrupt = 1, 85 .header_length = 4, 86 }; 87 88 static void isight_update_pointers(struct isight *isight, unsigned int count) 89 { 90 struct snd_pcm_runtime *runtime = isight->pcm->runtime; 91 unsigned int ptr; 92 93 smp_wmb(); /* update buffer data before buffer pointer */ 94 95 ptr = isight->buffer_pointer; 96 ptr += count; 97 if (ptr >= runtime->buffer_size) 98 ptr -= runtime->buffer_size; 99 ACCESS_ONCE(isight->buffer_pointer) = ptr; 100 101 isight->period_counter += count; 102 if (isight->period_counter >= runtime->period_size) { 103 isight->period_counter -= runtime->period_size; 104 snd_pcm_period_elapsed(isight->pcm); 105 } 106 } 107 108 static void isight_samples(struct isight *isight, 109 const __be16 *samples, unsigned int count) 110 { 111 struct snd_pcm_runtime *runtime; 112 unsigned int count1; 113 114 if (!ACCESS_ONCE(isight->pcm_running)) 115 return; 116 117 runtime = isight->pcm->runtime; 118 if (isight->buffer_pointer + count <= runtime->buffer_size) { 119 memcpy(runtime->dma_area + isight->buffer_pointer * 4, 120 samples, count * 4); 121 } else { 122 count1 = runtime->buffer_size - isight->buffer_pointer; 123 memcpy(runtime->dma_area + isight->buffer_pointer * 4, 124 samples, count1 * 4); 125 samples += count1 * 2; 126 memcpy(runtime->dma_area, samples, (count - count1) * 4); 127 } 128 129 isight_update_pointers(isight, count); 130 } 131 132 static void isight_pcm_abort(struct isight *isight) 133 { 134 unsigned long flags; 135 136 if (ACCESS_ONCE(isight->pcm_active)) { 137 snd_pcm_stream_lock_irqsave(isight->pcm, flags); 138 if (snd_pcm_running(isight->pcm)) 139 snd_pcm_stop(isight->pcm, SNDRV_PCM_STATE_XRUN); 140 snd_pcm_stream_unlock_irqrestore(isight->pcm, flags); 141 } 142 } 143 144 static void isight_dropped_samples(struct isight *isight, unsigned int total) 145 { 146 struct snd_pcm_runtime *runtime; 147 u32 dropped; 148 unsigned int count1; 149 150 if (!ACCESS_ONCE(isight->pcm_running)) 151 return; 152 153 runtime = isight->pcm->runtime; 154 dropped = total - isight->total_samples; 155 if (dropped < runtime->buffer_size) { 156 if (isight->buffer_pointer + dropped <= runtime->buffer_size) { 157 memset(runtime->dma_area + isight->buffer_pointer * 4, 158 0, dropped * 4); 159 } else { 160 count1 = runtime->buffer_size - isight->buffer_pointer; 161 memset(runtime->dma_area + isight->buffer_pointer * 4, 162 0, count1 * 4); 163 memset(runtime->dma_area, 0, (dropped - count1) * 4); 164 } 165 isight_update_pointers(isight, dropped); 166 } else { 167 isight_pcm_abort(isight); 168 } 169 } 170 171 static void isight_packet(struct fw_iso_context *context, u32 cycle, 172 size_t header_length, void *header, void *data) 173 { 174 struct isight *isight = data; 175 const struct audio_payload *payload; 176 unsigned int index, length, count, total; 177 int err; 178 179 if (isight->packet_index < 0) 180 return; 181 index = isight->packet_index; 182 payload = isight->buffer.packets[index].buffer; 183 length = be32_to_cpup(header) >> 16; 184 185 if (likely(length >= 16 && 186 payload->signature == cpu_to_be32(0x73676874/*"sght"*/))) { 187 count = be32_to_cpu(payload->sample_count); 188 if (likely(count <= (length - 16) / 4)) { 189 total = be32_to_cpu(payload->sample_total); 190 if (unlikely(total != isight->total_samples)) { 191 if (!isight->first_packet) 192 isight_dropped_samples(isight, total); 193 isight->first_packet = false; 194 isight->total_samples = total; 195 } 196 197 isight_samples(isight, payload->samples, count); 198 isight->total_samples += count; 199 } 200 } 201 202 err = fw_iso_context_queue(isight->context, &audio_packet, 203 &isight->buffer.iso_buffer, 204 isight->buffer.packets[index].offset); 205 if (err < 0) { 206 dev_err(&isight->unit->device, "queueing error: %d\n", err); 207 isight_pcm_abort(isight); 208 isight->packet_index = -1; 209 return; 210 } 211 fw_iso_context_queue_flush(isight->context); 212 213 if (++index >= QUEUE_LENGTH) 214 index = 0; 215 isight->packet_index = index; 216 } 217 218 static int isight_connect(struct isight *isight) 219 { 220 int ch, err, rcode, errors = 0; 221 __be32 value; 222 223 retry_after_bus_reset: 224 ch = fw_iso_resources_allocate(&isight->resources, 225 sizeof(struct audio_payload), 226 isight->device->max_speed); 227 if (ch < 0) { 228 err = ch; 229 goto error; 230 } 231 232 value = cpu_to_be32(ch | (isight->device->max_speed << SPEED_SHIFT)); 233 for (;;) { 234 rcode = fw_run_transaction( 235 isight->device->card, 236 TCODE_WRITE_QUADLET_REQUEST, 237 isight->device->node_id, 238 isight->resources.generation, 239 isight->device->max_speed, 240 isight->audio_base + REG_ISO_TX_CONFIG, 241 &value, 4); 242 if (rcode == RCODE_COMPLETE) { 243 return 0; 244 } else if (rcode == RCODE_GENERATION) { 245 fw_iso_resources_free(&isight->resources); 246 goto retry_after_bus_reset; 247 } else if (rcode_is_permanent_error(rcode) || ++errors >= 3) { 248 err = -EIO; 249 goto err_resources; 250 } 251 msleep(5); 252 } 253 254 err_resources: 255 fw_iso_resources_free(&isight->resources); 256 error: 257 return err; 258 } 259 260 static int isight_open(struct snd_pcm_substream *substream) 261 { 262 static const struct snd_pcm_hardware hardware = { 263 .info = SNDRV_PCM_INFO_MMAP | 264 SNDRV_PCM_INFO_MMAP_VALID | 265 SNDRV_PCM_INFO_BATCH | 266 SNDRV_PCM_INFO_INTERLEAVED | 267 SNDRV_PCM_INFO_BLOCK_TRANSFER, 268 .formats = SNDRV_PCM_FMTBIT_S16_BE, 269 .rates = SNDRV_PCM_RATE_48000, 270 .rate_min = 48000, 271 .rate_max = 48000, 272 .channels_min = 2, 273 .channels_max = 2, 274 .buffer_bytes_max = 4 * 1024 * 1024, 275 .period_bytes_min = MAX_FRAMES_PER_PACKET * 4, 276 .period_bytes_max = 1024 * 1024, 277 .periods_min = 2, 278 .periods_max = UINT_MAX, 279 }; 280 struct isight *isight = substream->private_data; 281 282 substream->runtime->hw = hardware; 283 284 return iso_packets_buffer_init(&isight->buffer, isight->unit, 285 QUEUE_LENGTH, 286 sizeof(struct audio_payload), 287 DMA_FROM_DEVICE); 288 } 289 290 static int isight_close(struct snd_pcm_substream *substream) 291 { 292 struct isight *isight = substream->private_data; 293 294 iso_packets_buffer_destroy(&isight->buffer, isight->unit); 295 296 return 0; 297 } 298 299 static int isight_hw_params(struct snd_pcm_substream *substream, 300 struct snd_pcm_hw_params *hw_params) 301 { 302 struct isight *isight = substream->private_data; 303 int err; 304 305 err = snd_pcm_lib_alloc_vmalloc_buffer(substream, 306 params_buffer_bytes(hw_params)); 307 if (err < 0) 308 return err; 309 310 ACCESS_ONCE(isight->pcm_active) = true; 311 312 return 0; 313 } 314 315 static int reg_read(struct isight *isight, int offset, __be32 *value) 316 { 317 return snd_fw_transaction(isight->unit, TCODE_READ_QUADLET_REQUEST, 318 isight->audio_base + offset, value, 4); 319 } 320 321 static int reg_write(struct isight *isight, int offset, __be32 value) 322 { 323 return snd_fw_transaction(isight->unit, TCODE_WRITE_QUADLET_REQUEST, 324 isight->audio_base + offset, &value, 4); 325 } 326 327 static void isight_stop_streaming(struct isight *isight) 328 { 329 if (!isight->context) 330 return; 331 332 fw_iso_context_stop(isight->context); 333 fw_iso_context_destroy(isight->context); 334 isight->context = NULL; 335 fw_iso_resources_free(&isight->resources); 336 reg_write(isight, REG_AUDIO_ENABLE, 0); 337 } 338 339 static int isight_hw_free(struct snd_pcm_substream *substream) 340 { 341 struct isight *isight = substream->private_data; 342 343 ACCESS_ONCE(isight->pcm_active) = false; 344 345 mutex_lock(&isight->mutex); 346 isight_stop_streaming(isight); 347 mutex_unlock(&isight->mutex); 348 349 return snd_pcm_lib_free_vmalloc_buffer(substream); 350 } 351 352 static int isight_start_streaming(struct isight *isight) 353 { 354 unsigned int i; 355 int err; 356 357 if (isight->context) { 358 if (isight->packet_index < 0) 359 isight_stop_streaming(isight); 360 else 361 return 0; 362 } 363 364 err = reg_write(isight, REG_SAMPLE_RATE, cpu_to_be32(RATE_48000)); 365 if (err < 0) 366 goto error; 367 368 err = isight_connect(isight); 369 if (err < 0) 370 goto error; 371 372 err = reg_write(isight, REG_AUDIO_ENABLE, cpu_to_be32(AUDIO_ENABLE)); 373 if (err < 0) 374 goto err_resources; 375 376 isight->context = fw_iso_context_create(isight->device->card, 377 FW_ISO_CONTEXT_RECEIVE, 378 isight->resources.channel, 379 isight->device->max_speed, 380 4, isight_packet, isight); 381 if (IS_ERR(isight->context)) { 382 err = PTR_ERR(isight->context); 383 isight->context = NULL; 384 goto err_resources; 385 } 386 387 for (i = 0; i < QUEUE_LENGTH; ++i) { 388 err = fw_iso_context_queue(isight->context, &audio_packet, 389 &isight->buffer.iso_buffer, 390 isight->buffer.packets[i].offset); 391 if (err < 0) 392 goto err_context; 393 } 394 395 isight->first_packet = true; 396 isight->packet_index = 0; 397 398 err = fw_iso_context_start(isight->context, -1, 0, 399 FW_ISO_CONTEXT_MATCH_ALL_TAGS/*?*/); 400 if (err < 0) 401 goto err_context; 402 403 return 0; 404 405 err_context: 406 fw_iso_context_destroy(isight->context); 407 isight->context = NULL; 408 err_resources: 409 fw_iso_resources_free(&isight->resources); 410 reg_write(isight, REG_AUDIO_ENABLE, 0); 411 error: 412 return err; 413 } 414 415 static int isight_prepare(struct snd_pcm_substream *substream) 416 { 417 struct isight *isight = substream->private_data; 418 int err; 419 420 isight->buffer_pointer = 0; 421 isight->period_counter = 0; 422 423 mutex_lock(&isight->mutex); 424 err = isight_start_streaming(isight); 425 mutex_unlock(&isight->mutex); 426 427 return err; 428 } 429 430 static int isight_trigger(struct snd_pcm_substream *substream, int cmd) 431 { 432 struct isight *isight = substream->private_data; 433 434 switch (cmd) { 435 case SNDRV_PCM_TRIGGER_START: 436 ACCESS_ONCE(isight->pcm_running) = true; 437 break; 438 case SNDRV_PCM_TRIGGER_STOP: 439 ACCESS_ONCE(isight->pcm_running) = false; 440 break; 441 default: 442 return -EINVAL; 443 } 444 return 0; 445 } 446 447 static snd_pcm_uframes_t isight_pointer(struct snd_pcm_substream *substream) 448 { 449 struct isight *isight = substream->private_data; 450 451 return ACCESS_ONCE(isight->buffer_pointer); 452 } 453 454 static int isight_create_pcm(struct isight *isight) 455 { 456 static struct snd_pcm_ops ops = { 457 .open = isight_open, 458 .close = isight_close, 459 .ioctl = snd_pcm_lib_ioctl, 460 .hw_params = isight_hw_params, 461 .hw_free = isight_hw_free, 462 .prepare = isight_prepare, 463 .trigger = isight_trigger, 464 .pointer = isight_pointer, 465 .page = snd_pcm_lib_get_vmalloc_page, 466 .mmap = snd_pcm_lib_mmap_vmalloc, 467 }; 468 struct snd_pcm *pcm; 469 int err; 470 471 err = snd_pcm_new(isight->card, "iSight", 0, 0, 1, &pcm); 472 if (err < 0) 473 return err; 474 pcm->private_data = isight; 475 strcpy(pcm->name, "iSight"); 476 isight->pcm = pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream; 477 isight->pcm->ops = &ops; 478 479 return 0; 480 } 481 482 static int isight_gain_info(struct snd_kcontrol *ctl, 483 struct snd_ctl_elem_info *info) 484 { 485 struct isight *isight = ctl->private_data; 486 487 info->type = SNDRV_CTL_ELEM_TYPE_INTEGER; 488 info->count = 1; 489 info->value.integer.min = isight->gain_min; 490 info->value.integer.max = isight->gain_max; 491 492 return 0; 493 } 494 495 static int isight_gain_get(struct snd_kcontrol *ctl, 496 struct snd_ctl_elem_value *value) 497 { 498 struct isight *isight = ctl->private_data; 499 __be32 gain; 500 int err; 501 502 err = reg_read(isight, REG_GAIN, &gain); 503 if (err < 0) 504 return err; 505 506 value->value.integer.value[0] = (s32)be32_to_cpu(gain); 507 508 return 0; 509 } 510 511 static int isight_gain_put(struct snd_kcontrol *ctl, 512 struct snd_ctl_elem_value *value) 513 { 514 struct isight *isight = ctl->private_data; 515 516 if (value->value.integer.value[0] < isight->gain_min || 517 value->value.integer.value[0] > isight->gain_max) 518 return -EINVAL; 519 520 return reg_write(isight, REG_GAIN, 521 cpu_to_be32(value->value.integer.value[0])); 522 } 523 524 static int isight_mute_get(struct snd_kcontrol *ctl, 525 struct snd_ctl_elem_value *value) 526 { 527 struct isight *isight = ctl->private_data; 528 __be32 mute; 529 int err; 530 531 err = reg_read(isight, REG_MUTE, &mute); 532 if (err < 0) 533 return err; 534 535 value->value.integer.value[0] = !mute; 536 537 return 0; 538 } 539 540 static int isight_mute_put(struct snd_kcontrol *ctl, 541 struct snd_ctl_elem_value *value) 542 { 543 struct isight *isight = ctl->private_data; 544 545 return reg_write(isight, REG_MUTE, 546 (__force __be32)!value->value.integer.value[0]); 547 } 548 549 static int isight_create_mixer(struct isight *isight) 550 { 551 static const struct snd_kcontrol_new gain_control = { 552 .iface = SNDRV_CTL_ELEM_IFACE_MIXER, 553 .name = "Mic Capture Volume", 554 .access = SNDRV_CTL_ELEM_ACCESS_READWRITE | 555 SNDRV_CTL_ELEM_ACCESS_TLV_READ, 556 .info = isight_gain_info, 557 .get = isight_gain_get, 558 .put = isight_gain_put, 559 }; 560 static const struct snd_kcontrol_new mute_control = { 561 .iface = SNDRV_CTL_ELEM_IFACE_MIXER, 562 .name = "Mic Capture Switch", 563 .info = snd_ctl_boolean_mono_info, 564 .get = isight_mute_get, 565 .put = isight_mute_put, 566 }; 567 __be32 value; 568 struct snd_kcontrol *ctl; 569 int err; 570 571 err = reg_read(isight, REG_GAIN_RAW_START, &value); 572 if (err < 0) 573 return err; 574 isight->gain_min = be32_to_cpu(value); 575 576 err = reg_read(isight, REG_GAIN_RAW_END, &value); 577 if (err < 0) 578 return err; 579 isight->gain_max = be32_to_cpu(value); 580 581 isight->gain_tlv[0] = SNDRV_CTL_TLVT_DB_MINMAX; 582 isight->gain_tlv[1] = 2 * sizeof(unsigned int); 583 584 err = reg_read(isight, REG_GAIN_DB_START, &value); 585 if (err < 0) 586 return err; 587 isight->gain_tlv[2] = (s32)be32_to_cpu(value) * 100; 588 589 err = reg_read(isight, REG_GAIN_DB_END, &value); 590 if (err < 0) 591 return err; 592 isight->gain_tlv[3] = (s32)be32_to_cpu(value) * 100; 593 594 ctl = snd_ctl_new1(&gain_control, isight); 595 if (ctl) 596 ctl->tlv.p = isight->gain_tlv; 597 err = snd_ctl_add(isight->card, ctl); 598 if (err < 0) 599 return err; 600 601 err = snd_ctl_add(isight->card, snd_ctl_new1(&mute_control, isight)); 602 if (err < 0) 603 return err; 604 605 return 0; 606 } 607 608 static void isight_card_free(struct snd_card *card) 609 { 610 struct isight *isight = card->private_data; 611 612 fw_iso_resources_destroy(&isight->resources); 613 fw_unit_put(isight->unit); 614 mutex_destroy(&isight->mutex); 615 } 616 617 static u64 get_unit_base(struct fw_unit *unit) 618 { 619 struct fw_csr_iterator i; 620 int key, value; 621 622 fw_csr_iterator_init(&i, unit->directory); 623 while (fw_csr_iterator_next(&i, &key, &value)) 624 if (key == CSR_OFFSET) 625 return CSR_REGISTER_BASE + value * 4; 626 return 0; 627 } 628 629 static int isight_probe(struct device *unit_dev) 630 { 631 struct fw_unit *unit = fw_unit(unit_dev); 632 struct fw_device *fw_dev = fw_parent_device(unit); 633 struct snd_card *card; 634 struct isight *isight; 635 int err; 636 637 err = snd_card_create(-1, NULL, THIS_MODULE, sizeof(*isight), &card); 638 if (err < 0) 639 return err; 640 snd_card_set_dev(card, unit_dev); 641 642 isight = card->private_data; 643 isight->card = card; 644 mutex_init(&isight->mutex); 645 isight->unit = fw_unit_get(unit); 646 isight->device = fw_dev; 647 isight->audio_base = get_unit_base(unit); 648 if (!isight->audio_base) { 649 dev_err(&unit->device, "audio unit base not found\n"); 650 err = -ENXIO; 651 goto err_unit; 652 } 653 fw_iso_resources_init(&isight->resources, unit); 654 655 card->private_free = isight_card_free; 656 657 strcpy(card->driver, "iSight"); 658 strcpy(card->shortname, "Apple iSight"); 659 snprintf(card->longname, sizeof(card->longname), 660 "Apple iSight (GUID %08x%08x) at %s, S%d", 661 fw_dev->config_rom[3], fw_dev->config_rom[4], 662 dev_name(&unit->device), 100 << fw_dev->max_speed); 663 strcpy(card->mixername, "iSight"); 664 665 err = isight_create_pcm(isight); 666 if (err < 0) 667 goto error; 668 669 err = isight_create_mixer(isight); 670 if (err < 0) 671 goto error; 672 673 err = snd_card_register(card); 674 if (err < 0) 675 goto error; 676 677 dev_set_drvdata(unit_dev, isight); 678 679 return 0; 680 681 err_unit: 682 fw_unit_put(isight->unit); 683 mutex_destroy(&isight->mutex); 684 error: 685 snd_card_free(card); 686 return err; 687 } 688 689 static int isight_remove(struct device *dev) 690 { 691 struct isight *isight = dev_get_drvdata(dev); 692 693 isight_pcm_abort(isight); 694 695 snd_card_disconnect(isight->card); 696 697 mutex_lock(&isight->mutex); 698 isight_stop_streaming(isight); 699 mutex_unlock(&isight->mutex); 700 701 snd_card_free_when_closed(isight->card); 702 703 return 0; 704 } 705 706 static void isight_bus_reset(struct fw_unit *unit) 707 { 708 struct isight *isight = dev_get_drvdata(&unit->device); 709 710 if (fw_iso_resources_update(&isight->resources) < 0) { 711 isight_pcm_abort(isight); 712 713 mutex_lock(&isight->mutex); 714 isight_stop_streaming(isight); 715 mutex_unlock(&isight->mutex); 716 } 717 } 718 719 static const struct ieee1394_device_id isight_id_table[] = { 720 { 721 .match_flags = IEEE1394_MATCH_SPECIFIER_ID | 722 IEEE1394_MATCH_VERSION, 723 .specifier_id = OUI_APPLE, 724 .version = SW_ISIGHT_AUDIO, 725 }, 726 { } 727 }; 728 MODULE_DEVICE_TABLE(ieee1394, isight_id_table); 729 730 static struct fw_driver isight_driver = { 731 .driver = { 732 .owner = THIS_MODULE, 733 .name = KBUILD_MODNAME, 734 .bus = &fw_bus_type, 735 .probe = isight_probe, 736 .remove = isight_remove, 737 }, 738 .update = isight_bus_reset, 739 .id_table = isight_id_table, 740 }; 741 742 static int __init alsa_isight_init(void) 743 { 744 return driver_register(&isight_driver.driver); 745 } 746 747 static void __exit alsa_isight_exit(void) 748 { 749 driver_unregister(&isight_driver.driver); 750 } 751 752 module_init(alsa_isight_init); 753 module_exit(alsa_isight_exit); 754