tools/iio/iio_generic_buffer.c

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