1 // SPDX-License-Identifier: GPL-2.0-only 2 /* Industrialio buffer test code. 3 * 4 * Copyright (c) 2008 Jonathan Cameron 5 * 6 * This program is primarily intended as an example application. 7 * Reads the current buffer setup from sysfs and starts a short capture 8 * from the specified device, pretty printing the result after appropriate 9 * conversion. 10 * 11 * Command line parameters 12 * generic_buffer -n <device_name> -t <trigger_name> 13 * If trigger name is not specified the program assumes you want a dataready 14 * trigger associated with the device and goes looking for it. 15 */ 16 17 #include <unistd.h> 18 #include <stdlib.h> 19 #include <dirent.h> 20 #include <fcntl.h> 21 #include <stdio.h> 22 #include <errno.h> 23 #include <sys/stat.h> 24 #include <sys/dir.h> 25 #include <linux/types.h> 26 #include <string.h> 27 #include <poll.h> 28 #include <endian.h> 29 #include <getopt.h> 30 #include <inttypes.h> 31 #include <stdbool.h> 32 #include <signal.h> 33 #include <sys/ioctl.h> 34 #include <linux/iio/buffer.h> 35 #include "iio_utils.h" 36 37 /** 38 * enum autochan - state for the automatic channel enabling mechanism 39 */ 40 enum autochan { 41 AUTOCHANNELS_DISABLED, 42 AUTOCHANNELS_ENABLED, 43 AUTOCHANNELS_ACTIVE, 44 }; 45 46 /** 47 * size_from_channelarray() - calculate the storage size of a scan 48 * @channels: the channel info array 49 * @num_channels: number of channels 50 * 51 * Has the side effect of filling the channels[i].location values used 52 * in processing the buffer output. 53 **/ 54 static unsigned int size_from_channelarray(struct iio_channel_info *channels, int num_channels) 55 { 56 unsigned int bytes = 0; 57 int i = 0, max = 0; 58 unsigned int misalignment; 59 60 while (i < num_channels) { 61 if (channels[i].bytes > max) 62 max = channels[i].bytes; 63 if (bytes % channels[i].bytes == 0) 64 channels[i].location = bytes; 65 else 66 channels[i].location = bytes - bytes % channels[i].bytes 67 + channels[i].bytes; 68 69 bytes = channels[i].location + channels[i].bytes; 70 i++; 71 } 72 /* 73 * We want the data in next sample to also be properly aligned so 74 * we'll add padding at the end if needed. Adding padding only 75 * works for channel data which size is 2^n bytes. 76 */ 77 misalignment = bytes % max; 78 if (misalignment) 79 bytes += max - misalignment; 80 81 return bytes; 82 } 83 84 static void print1byte(uint8_t input, struct iio_channel_info *info) 85 { 86 /* 87 * Shift before conversion to avoid sign extension 88 * of left aligned data 89 */ 90 input >>= info->shift; 91 input &= info->mask; 92 if (info->is_signed) { 93 int8_t val = (int8_t)(input << (8 - info->bits_used)) >> 94 (8 - info->bits_used); 95 printf("%05f ", ((float)val + info->offset) * info->scale); 96 } else { 97 printf("%05f ", ((float)input + info->offset) * info->scale); 98 } 99 } 100 101 static void print2byte(uint16_t input, struct iio_channel_info *info) 102 { 103 /* First swap if incorrect endian */ 104 if (info->be) 105 input = be16toh(input); 106 else 107 input = le16toh(input); 108 109 /* 110 * Shift before conversion to avoid sign extension 111 * of left aligned data 112 */ 113 input >>= info->shift; 114 input &= info->mask; 115 if (info->is_signed) { 116 int16_t val = (int16_t)(input << (16 - info->bits_used)) >> 117 (16 - info->bits_used); 118 printf("%05f ", ((float)val + info->offset) * info->scale); 119 } else { 120 printf("%05f ", ((float)input + info->offset) * info->scale); 121 } 122 } 123 124 static void print4byte(uint32_t input, struct iio_channel_info *info) 125 { 126 /* First swap if incorrect endian */ 127 if (info->be) 128 input = be32toh(input); 129 else 130 input = le32toh(input); 131 132 /* 133 * Shift before conversion to avoid sign extension 134 * of left aligned data 135 */ 136 input >>= info->shift; 137 input &= info->mask; 138 if (info->is_signed) { 139 int32_t val = (int32_t)(input << (32 - info->bits_used)) >> 140 (32 - info->bits_used); 141 printf("%05f ", ((float)val + info->offset) * info->scale); 142 } else { 143 printf("%05f ", ((float)input + info->offset) * info->scale); 144 } 145 } 146 147 static void print8byte(uint64_t input, struct iio_channel_info *info) 148 { 149 /* First swap if incorrect endian */ 150 if (info->be) 151 input = be64toh(input); 152 else 153 input = le64toh(input); 154 155 /* 156 * Shift before conversion to avoid sign extension 157 * of left aligned data 158 */ 159 input >>= info->shift; 160 input &= info->mask; 161 if (info->is_signed) { 162 int64_t val = (int64_t)(input << (64 - info->bits_used)) >> 163 (64 - info->bits_used); 164 /* special case for timestamp */ 165 if (info->scale == 1.0f && info->offset == 0.0f) 166 printf("%" PRId64 " ", val); 167 else 168 printf("%05f ", 169 ((float)val + info->offset) * info->scale); 170 } else { 171 printf("%05f ", ((float)input + info->offset) * info->scale); 172 } 173 } 174 175 /** 176 * process_scan() - print out the values in SI units 177 * @data: pointer to the start of the scan 178 * @channels: information about the channels. 179 * Note: size_from_channelarray must have been called first 180 * to fill the location offsets. 181 * @num_channels: number of channels 182 **/ 183 static void process_scan(char *data, struct iio_channel_info *channels, 184 int num_channels) 185 { 186 int k; 187 188 for (k = 0; k < num_channels; k++) 189 switch (channels[k].bytes) { 190 /* only a few cases implemented so far */ 191 case 1: 192 print1byte(*(uint8_t *)(data + channels[k].location), 193 &channels[k]); 194 break; 195 case 2: 196 print2byte(*(uint16_t *)(data + channels[k].location), 197 &channels[k]); 198 break; 199 case 4: 200 print4byte(*(uint32_t *)(data + channels[k].location), 201 &channels[k]); 202 break; 203 case 8: 204 print8byte(*(uint64_t *)(data + channels[k].location), 205 &channels[k]); 206 break; 207 default: 208 break; 209 } 210 printf("\n"); 211 } 212 213 static int enable_disable_all_channels(char *dev_dir_name, int buffer_idx, int enable) 214 { 215 const struct dirent *ent; 216 char scanelemdir[256]; 217 DIR *dp; 218 int ret; 219 220 snprintf(scanelemdir, sizeof(scanelemdir), 221 FORMAT_SCAN_ELEMENTS_DIR, dev_dir_name, buffer_idx); 222 scanelemdir[sizeof(scanelemdir)-1] = '\0'; 223 224 dp = opendir(scanelemdir); 225 if (!dp) { 226 fprintf(stderr, "Enabling/disabling channels: can't open %s\n", 227 scanelemdir); 228 return -EIO; 229 } 230 231 ret = -ENOENT; 232 while (ent = readdir(dp), ent) { 233 if (iioutils_check_suffix(ent->d_name, "_en")) { 234 printf("%sabling: %s\n", 235 enable ? "En" : "Dis", 236 ent->d_name); 237 ret = write_sysfs_int(ent->d_name, scanelemdir, 238 enable); 239 if (ret < 0) 240 fprintf(stderr, "Failed to enable/disable %s\n", 241 ent->d_name); 242 } 243 } 244 245 if (closedir(dp) == -1) { 246 perror("Enabling/disabling channels: " 247 "Failed to close directory"); 248 return -errno; 249 } 250 return 0; 251 } 252 253 static void print_usage(void) 254 { 255 fprintf(stderr, "Usage: generic_buffer [options]...\n" 256 "Capture, convert and output data from IIO device buffer\n" 257 " -a Auto-activate all available channels\n" 258 " -A Force-activate ALL channels\n" 259 " -b <n> The buffer which to open (by index), default 0\n" 260 " -c <n> Do n conversions, or loop forever if n < 0\n" 261 " -e Disable wait for event (new data)\n" 262 " -g Use trigger-less mode\n" 263 " -l <n> Set buffer length to n samples\n" 264 " --device-name -n <name>\n" 265 " --device-num -N <num>\n" 266 " Set device by name or number (mandatory)\n" 267 " --trigger-name -t <name>\n" 268 " --trigger-num -T <num>\n" 269 " Set trigger by name or number\n" 270 " -w <n> Set delay between reads in us (event-less mode)\n"); 271 } 272 273 static enum autochan autochannels = AUTOCHANNELS_DISABLED; 274 static char *dev_dir_name = NULL; 275 static char *buf_dir_name = NULL; 276 static int buffer_idx = 0; 277 static bool current_trigger_set = false; 278 279 static void cleanup(void) 280 { 281 int ret; 282 283 /* Disable trigger */ 284 if (dev_dir_name && current_trigger_set) { 285 /* Disconnect the trigger - just write a dummy name. */ 286 ret = write_sysfs_string("trigger/current_trigger", 287 dev_dir_name, "NULL"); 288 if (ret < 0) 289 fprintf(stderr, "Failed to disable trigger: %s\n", 290 strerror(-ret)); 291 current_trigger_set = false; 292 } 293 294 /* Disable buffer */ 295 if (buf_dir_name) { 296 ret = write_sysfs_int("enable", buf_dir_name, 0); 297 if (ret < 0) 298 fprintf(stderr, "Failed to disable buffer: %s\n", 299 strerror(-ret)); 300 } 301 302 /* Disable channels if auto-enabled */ 303 if (dev_dir_name && autochannels == AUTOCHANNELS_ACTIVE) { 304 ret = enable_disable_all_channels(dev_dir_name, buffer_idx, 0); 305 if (ret) 306 fprintf(stderr, "Failed to disable all channels\n"); 307 autochannels = AUTOCHANNELS_DISABLED; 308 } 309 } 310 311 static void sig_handler(int signum) 312 { 313 fprintf(stderr, "Caught signal %d\n", signum); 314 cleanup(); 315 exit(-signum); 316 } 317 318 static void register_cleanup(void) 319 { 320 struct sigaction sa = { .sa_handler = sig_handler }; 321 const int signums[] = { SIGINT, SIGTERM, SIGABRT }; 322 int ret, i; 323 324 for (i = 0; i < ARRAY_SIZE(signums); ++i) { 325 ret = sigaction(signums[i], &sa, NULL); 326 if (ret) { 327 perror("Failed to register signal handler"); 328 exit(-1); 329 } 330 } 331 } 332 333 static const struct option longopts[] = { 334 { "device-name", 1, 0, 'n' }, 335 { "device-num", 1, 0, 'N' }, 336 { "trigger-name", 1, 0, 't' }, 337 { "trigger-num", 1, 0, 'T' }, 338 { }, 339 }; 340 341 int main(int argc, char **argv) 342 { 343 long long num_loops = 2; 344 unsigned long timedelay = 1000000; 345 unsigned long buf_len = 128; 346 347 ssize_t i; 348 unsigned long long j; 349 unsigned long toread; 350 int ret, c; 351 struct stat st; 352 int fd = -1; 353 int buf_fd = -1; 354 355 int num_channels = 0; 356 char *trigger_name = NULL, *device_name = NULL; 357 358 char *data = NULL; 359 ssize_t read_size; 360 int dev_num = -1, trig_num = -1; 361 char *buffer_access = NULL; 362 unsigned int scan_size; 363 int noevents = 0; 364 int notrigger = 0; 365 char *dummy; 366 bool force_autochannels = false; 367 368 struct iio_channel_info *channels = NULL; 369 370 register_cleanup(); 371 372 while ((c = getopt_long(argc, argv, "aAb:c:egl:n:N:t:T:w:?", longopts, 373 NULL)) != -1) { 374 switch (c) { 375 case 'a': 376 autochannels = AUTOCHANNELS_ENABLED; 377 break; 378 case 'A': 379 autochannels = AUTOCHANNELS_ENABLED; 380 force_autochannels = true; 381 break; 382 case 'b': 383 errno = 0; 384 buffer_idx = strtoll(optarg, &dummy, 10); 385 if (errno) { 386 ret = -errno; 387 goto error; 388 } 389 if (buffer_idx < 0) { 390 ret = -ERANGE; 391 goto error; 392 } 393 394 break; 395 case 'c': 396 errno = 0; 397 num_loops = strtoll(optarg, &dummy, 10); 398 if (errno) { 399 ret = -errno; 400 goto error; 401 } 402 403 break; 404 case 'e': 405 noevents = 1; 406 break; 407 case 'g': 408 notrigger = 1; 409 break; 410 case 'l': 411 errno = 0; 412 buf_len = strtoul(optarg, &dummy, 10); 413 if (errno) { 414 ret = -errno; 415 goto error; 416 } 417 418 break; 419 case 'n': 420 device_name = strdup(optarg); 421 break; 422 case 'N': 423 errno = 0; 424 dev_num = strtoul(optarg, &dummy, 10); 425 if (errno) { 426 ret = -errno; 427 goto error; 428 } 429 break; 430 case 't': 431 trigger_name = strdup(optarg); 432 break; 433 case 'T': 434 errno = 0; 435 trig_num = strtoul(optarg, &dummy, 10); 436 if (errno) 437 return -errno; 438 break; 439 case 'w': 440 errno = 0; 441 timedelay = strtoul(optarg, &dummy, 10); 442 if (errno) { 443 ret = -errno; 444 goto error; 445 } 446 break; 447 case '?': 448 print_usage(); 449 ret = -1; 450 goto error; 451 } 452 } 453 454 /* Find the device requested */ 455 if (dev_num < 0 && !device_name) { 456 fprintf(stderr, "Device not set\n"); 457 print_usage(); 458 ret = -1; 459 goto error; 460 } else if (dev_num >= 0 && device_name) { 461 fprintf(stderr, "Only one of --device-num or --device-name needs to be set\n"); 462 print_usage(); 463 ret = -1; 464 goto error; 465 } else if (dev_num < 0) { 466 dev_num = find_type_by_name(device_name, "iio:device"); 467 if (dev_num < 0) { 468 fprintf(stderr, "Failed to find the %s\n", device_name); 469 ret = dev_num; 470 goto error; 471 } 472 } 473 printf("iio device number being used is %d\n", dev_num); 474 475 ret = asprintf(&dev_dir_name, "%siio:device%d", iio_dir, dev_num); 476 if (ret < 0) 477 return -ENOMEM; 478 /* Fetch device_name if specified by number */ 479 if (!device_name) { 480 device_name = malloc(IIO_MAX_NAME_LENGTH); 481 if (!device_name) { 482 ret = -ENOMEM; 483 goto error; 484 } 485 ret = read_sysfs_string("name", dev_dir_name, device_name); 486 if (ret < 0) { 487 fprintf(stderr, "Failed to read name of device %d\n", dev_num); 488 goto error; 489 } 490 } 491 492 if (notrigger) { 493 printf("trigger-less mode selected\n"); 494 } else if (trig_num >= 0) { 495 char *trig_dev_name; 496 ret = asprintf(&trig_dev_name, "%strigger%d", iio_dir, trig_num); 497 if (ret < 0) { 498 return -ENOMEM; 499 } 500 trigger_name = malloc(IIO_MAX_NAME_LENGTH); 501 if (!trigger_name) { 502 ret = -ENOMEM; 503 goto error; 504 } 505 ret = read_sysfs_string("name", trig_dev_name, trigger_name); 506 free(trig_dev_name); 507 if (ret < 0) { 508 fprintf(stderr, "Failed to read trigger%d name from\n", trig_num); 509 return ret; 510 } 511 printf("iio trigger number being used is %d\n", trig_num); 512 } else { 513 if (!trigger_name) { 514 /* 515 * Build the trigger name. If it is device associated 516 * its name is <device_name>_dev[n] where n matches 517 * the device number found above. 518 */ 519 ret = asprintf(&trigger_name, 520 "%s-dev%d", device_name, dev_num); 521 if (ret < 0) { 522 ret = -ENOMEM; 523 goto error; 524 } 525 } 526 527 /* Look for this "-devN" trigger */ 528 trig_num = find_type_by_name(trigger_name, "trigger"); 529 if (trig_num < 0) { 530 /* OK try the simpler "-trigger" suffix instead */ 531 free(trigger_name); 532 ret = asprintf(&trigger_name, 533 "%s-trigger", device_name); 534 if (ret < 0) { 535 ret = -ENOMEM; 536 goto error; 537 } 538 } 539 540 trig_num = find_type_by_name(trigger_name, "trigger"); 541 if (trig_num < 0) { 542 fprintf(stderr, "Failed to find the trigger %s\n", 543 trigger_name); 544 ret = trig_num; 545 goto error; 546 } 547 548 printf("iio trigger number being used is %d\n", trig_num); 549 } 550 551 /* 552 * Parse the files in scan_elements to identify what channels are 553 * present 554 */ 555 ret = build_channel_array(dev_dir_name, buffer_idx, &channels, &num_channels); 556 if (ret) { 557 fprintf(stderr, "Problem reading scan element information\n" 558 "diag %s\n", dev_dir_name); 559 goto error; 560 } 561 if (num_channels && autochannels == AUTOCHANNELS_ENABLED && 562 !force_autochannels) { 563 fprintf(stderr, "Auto-channels selected but some channels " 564 "are already activated in sysfs\n"); 565 fprintf(stderr, "Proceeding without activating any channels\n"); 566 } 567 568 if ((!num_channels && autochannels == AUTOCHANNELS_ENABLED) || 569 (autochannels == AUTOCHANNELS_ENABLED && force_autochannels)) { 570 fprintf(stderr, "Enabling all channels\n"); 571 572 ret = enable_disable_all_channels(dev_dir_name, buffer_idx, 1); 573 if (ret) { 574 fprintf(stderr, "Failed to enable all channels\n"); 575 goto error; 576 } 577 578 /* This flags that we need to disable the channels again */ 579 autochannels = AUTOCHANNELS_ACTIVE; 580 581 ret = build_channel_array(dev_dir_name, buffer_idx, &channels, 582 &num_channels); 583 if (ret) { 584 fprintf(stderr, "Problem reading scan element " 585 "information\n" 586 "diag %s\n", dev_dir_name); 587 goto error; 588 } 589 if (!num_channels) { 590 fprintf(stderr, "Still no channels after " 591 "auto-enabling, giving up\n"); 592 goto error; 593 } 594 } 595 596 if (!num_channels && autochannels == AUTOCHANNELS_DISABLED) { 597 fprintf(stderr, 598 "No channels are enabled, we have nothing to scan.\n"); 599 fprintf(stderr, "Enable channels manually in " 600 FORMAT_SCAN_ELEMENTS_DIR 601 "/*_en or pass -a to autoenable channels and " 602 "try again.\n", dev_dir_name, buffer_idx); 603 ret = -ENOENT; 604 goto error; 605 } 606 607 /* 608 * Construct the directory name for the associated buffer. 609 * As we know that the lis3l02dq has only one buffer this may 610 * be built rather than found. 611 */ 612 ret = asprintf(&buf_dir_name, 613 "%siio:device%d/buffer%d", iio_dir, dev_num, buffer_idx); 614 if (ret < 0) { 615 ret = -ENOMEM; 616 goto error; 617 } 618 619 if (stat(buf_dir_name, &st)) { 620 fprintf(stderr, "Could not stat() '%s', got error %d: %s\n", 621 buf_dir_name, errno, strerror(errno)); 622 ret = -errno; 623 goto error; 624 } 625 626 if (!S_ISDIR(st.st_mode)) { 627 fprintf(stderr, "File '%s' is not a directory\n", buf_dir_name); 628 ret = -EFAULT; 629 goto error; 630 } 631 632 if (!notrigger) { 633 printf("%s %s\n", dev_dir_name, trigger_name); 634 /* 635 * Set the device trigger to be the data ready trigger found 636 * above 637 */ 638 ret = write_sysfs_string_and_verify("trigger/current_trigger", 639 dev_dir_name, 640 trigger_name); 641 if (ret < 0) { 642 fprintf(stderr, 643 "Failed to write current_trigger file\n"); 644 goto error; 645 } 646 } 647 648 ret = asprintf(&buffer_access, "/dev/iio:device%d", dev_num); 649 if (ret < 0) { 650 ret = -ENOMEM; 651 goto error; 652 } 653 654 /* Attempt to open non blocking the access dev */ 655 fd = open(buffer_access, O_RDONLY | O_NONBLOCK); 656 if (fd == -1) { /* TODO: If it isn't there make the node */ 657 ret = -errno; 658 fprintf(stderr, "Failed to open %s\n", buffer_access); 659 goto error; 660 } 661 662 /* specify for which buffer index we want an FD */ 663 buf_fd = buffer_idx; 664 665 ret = ioctl(fd, IIO_BUFFER_GET_FD_IOCTL, &buf_fd); 666 if (ret == -1 || buf_fd == -1) { 667 ret = -errno; 668 if (ret == -ENODEV || ret == -EINVAL) 669 fprintf(stderr, 670 "Device does not have this many buffers\n"); 671 else 672 fprintf(stderr, "Failed to retrieve buffer fd\n"); 673 674 goto error; 675 } 676 677 /* Setup ring buffer parameters */ 678 ret = write_sysfs_int("length", buf_dir_name, buf_len); 679 if (ret < 0) 680 goto error; 681 682 /* Enable the buffer */ 683 ret = write_sysfs_int("enable", buf_dir_name, 1); 684 if (ret < 0) { 685 fprintf(stderr, 686 "Failed to enable buffer '%s': %s\n", 687 buf_dir_name, strerror(-ret)); 688 goto error; 689 } 690 691 scan_size = size_from_channelarray(channels, num_channels); 692 693 size_t total_buf_len = scan_size * buf_len; 694 695 if (scan_size > 0 && total_buf_len / scan_size != buf_len) { 696 ret = -EFAULT; 697 perror("Integer overflow happened when calculate scan_size * buf_len"); 698 goto error; 699 } 700 701 data = malloc(total_buf_len); 702 if (!data) { 703 ret = -ENOMEM; 704 goto error; 705 } 706 707 /** 708 * This check is being done here for sanity reasons, however it 709 * should be omitted under normal operation. 710 * If this is buffer0, we check that we get EBUSY after this point. 711 */ 712 if (buffer_idx == 0) { 713 errno = 0; 714 read_size = read(fd, data, 1); 715 if (read_size > -1 || errno != EBUSY) { 716 ret = -EFAULT; 717 perror("Reading from '%s' should not be possible after ioctl()"); 718 goto error; 719 } 720 } 721 722 /* close now the main chardev FD and let the buffer FD work */ 723 if (close(fd) == -1) 724 perror("Failed to close character device file"); 725 fd = -1; 726 727 for (j = 0; j < num_loops || num_loops < 0; j++) { 728 if (!noevents) { 729 struct pollfd pfd = { 730 .fd = buf_fd, 731 .events = POLLIN, 732 }; 733 734 ret = poll(&pfd, 1, -1); 735 if (ret < 0) { 736 ret = -errno; 737 goto error; 738 } else if (ret == 0) { 739 continue; 740 } 741 742 } else { 743 usleep(timedelay); 744 } 745 746 toread = buf_len; 747 748 read_size = read(buf_fd, data, toread * scan_size); 749 if (read_size < 0) { 750 if (errno == EAGAIN) { 751 fprintf(stderr, "nothing available\n"); 752 continue; 753 } else { 754 break; 755 } 756 } 757 for (i = 0; i < read_size / scan_size; i++) 758 process_scan(data + scan_size * i, channels, 759 num_channels); 760 } 761 762 error: 763 cleanup(); 764 765 if (fd >= 0 && close(fd) == -1) 766 perror("Failed to close character device"); 767 if (buf_fd >= 0 && close(buf_fd) == -1) 768 perror("Failed to close buffer"); 769 free(buffer_access); 770 free(data); 771 free(buf_dir_name); 772 for (i = num_channels - 1; i >= 0; i--) { 773 free(channels[i].name); 774 free(channels[i].generic_name); 775 } 776 free(channels); 777 free(trigger_name); 778 free(device_name); 779 free(dev_dir_name); 780 781 return ret; 782 } 783