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TOMOYO Linux Cross Reference
Linux/tools/iio/iio_generic_buffer.c

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  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                 "  --device-name -n <name>\n"
255                 "  --device-num -N <num>\n"
256                 "        Set device by name or number (mandatory)\n"
257                 "  --trigger-name -t <name>\n"
258                 "  --trigger-num -T <num>\n"
259                 "        Set trigger by name or number\n"
260                 "  -w <n>     Set delay between reads in us (event-less mode)\n");
261 }
262 
263 enum autochan autochannels = AUTOCHANNELS_DISABLED;
264 char *dev_dir_name = NULL;
265 char *buf_dir_name = NULL;
266 bool current_trigger_set = false;
267 
268 void cleanup(void)
269 {
270         int ret;
271 
272         /* Disable trigger */
273         if (dev_dir_name && current_trigger_set) {
274                 /* Disconnect the trigger - just write a dummy name. */
275                 ret = write_sysfs_string("trigger/current_trigger",
276                                          dev_dir_name, "NULL");
277                 if (ret < 0)
278                         fprintf(stderr, "Failed to disable trigger: %s\n",
279                                 strerror(-ret));
280                 current_trigger_set = false;
281         }
282 
283         /* Disable buffer */
284         if (buf_dir_name) {
285                 ret = write_sysfs_int("enable", buf_dir_name, 0);
286                 if (ret < 0)
287                         fprintf(stderr, "Failed to disable buffer: %s\n",
288                                 strerror(-ret));
289         }
290 
291         /* Disable channels if auto-enabled */
292         if (dev_dir_name && autochannels == AUTOCHANNELS_ACTIVE) {
293                 ret = enable_disable_all_channels(dev_dir_name, 0);
294                 if (ret)
295                         fprintf(stderr, "Failed to disable all channels\n");
296                 autochannels = AUTOCHANNELS_DISABLED;
297         }
298 }
299 
300 void sig_handler(int signum)
301 {
302         fprintf(stderr, "Caught signal %d\n", signum);
303         cleanup();
304         exit(-signum);
305 }
306 
307 void register_cleanup(void)
308 {
309         struct sigaction sa = { .sa_handler = sig_handler };
310         const int signums[] = { SIGINT, SIGTERM, SIGABRT };
311         int ret, i;
312 
313         for (i = 0; i < ARRAY_SIZE(signums); ++i) {
314                 ret = sigaction(signums[i], &sa, NULL);
315                 if (ret) {
316                         perror("Failed to register signal handler");
317                         exit(-1);
318                 }
319         }
320 }
321 
322 static const struct option longopts[] = {
323         { "device-name",        1, 0, 'n' },
324         { "device-num",         1, 0, 'N' },
325         { "trigger-name",       1, 0, 't' },
326         { "trigger-num",        1, 0, 'T' },
327         { },
328 };
329 
330 int main(int argc, char **argv)
331 {
332         unsigned long num_loops = 2;
333         unsigned long timedelay = 1000000;
334         unsigned long buf_len = 128;
335 
336         int ret, c, i, j, toread;
337         int fp = -1;
338 
339         int num_channels = 0;
340         char *trigger_name = NULL, *device_name = NULL;
341 
342         char *data = NULL;
343         ssize_t read_size;
344         int dev_num = -1, trig_num = -1;
345         char *buffer_access = NULL;
346         int scan_size;
347         int noevents = 0;
348         int notrigger = 0;
349         char *dummy;
350 
351         struct iio_channel_info *channels = NULL;
352 
353         register_cleanup();
354 
355         while ((c = getopt_long(argc, argv, "ac:egl:n:N:t:T:w:", longopts, NULL)) != -1) {
356                 switch (c) {
357                 case 'a':
358                         autochannels = AUTOCHANNELS_ENABLED;
359                         break;
360                 case 'c':
361                         errno = 0;
362                         num_loops = strtoul(optarg, &dummy, 10);
363                         if (errno) {
364                                 ret = -errno;
365                                 goto error;
366                         }
367 
368                         break;
369                 case 'e':
370                         noevents = 1;
371                         break;
372                 case 'g':
373                         notrigger = 1;
374                         break;
375                 case 'l':
376                         errno = 0;
377                         buf_len = strtoul(optarg, &dummy, 10);
378                         if (errno) {
379                                 ret = -errno;
380                                 goto error;
381                         }
382 
383                         break;
384                 case 'n':
385                         device_name = strdup(optarg);
386                         break;
387                 case 'N':
388                         errno = 0;
389                         dev_num = strtoul(optarg, &dummy, 10);
390                         if (errno) {
391                                 ret = -errno;
392                                 goto error;
393                         }
394                         break;
395                 case 't':
396                         trigger_name = strdup(optarg);
397                         break;
398                 case 'T':
399                         errno = 0;
400                         trig_num = strtoul(optarg, &dummy, 10);
401                         if (errno)
402                                 return -errno;
403                         break;
404                 case 'w':
405                         errno = 0;
406                         timedelay = strtoul(optarg, &dummy, 10);
407                         if (errno) {
408                                 ret = -errno;
409                                 goto error;
410                         }
411                         break;
412                 case '?':
413                         print_usage();
414                         ret = -1;
415                         goto error;
416                 }
417         }
418 
419         /* Find the device requested */
420         if (dev_num < 0 && !device_name) {
421                 fprintf(stderr, "Device not set\n");
422                 print_usage();
423                 ret = -1;
424                 goto error;
425         } else if (dev_num >= 0 && device_name) {
426                 fprintf(stderr, "Only one of --device-num or --device-name needs to be set\n");
427                 print_usage();
428                 ret = -1;
429                 goto error;
430         } else if (dev_num < 0) {
431                 dev_num = find_type_by_name(device_name, "iio:device");
432                 if (dev_num < 0) {
433                         fprintf(stderr, "Failed to find the %s\n", device_name);
434                         ret = dev_num;
435                         goto error;
436                 }
437         }
438         printf("iio device number being used is %d\n", dev_num);
439 
440         ret = asprintf(&dev_dir_name, "%siio:device%d", iio_dir, dev_num);
441         if (ret < 0)
442                 return -ENOMEM;
443         /* Fetch device_name if specified by number */
444         if (!device_name) {
445                 device_name = malloc(IIO_MAX_NAME_LENGTH);
446                 if (!device_name) {
447                         ret = -ENOMEM;
448                         goto error;
449                 }
450                 ret = read_sysfs_string("name", dev_dir_name, device_name);
451                 if (ret < 0) {
452                         fprintf(stderr, "Failed to read name of device %d\n", dev_num);
453                         goto error;
454                 }
455         }
456 
457         if (notrigger) {
458                 printf("trigger-less mode selected\n");
459         } else if (trig_num >= 0) {
460                 char *trig_dev_name;
461                 ret = asprintf(&trig_dev_name, "%strigger%d", iio_dir, trig_num);
462                 if (ret < 0) {
463                         return -ENOMEM;
464                 }
465                 trigger_name = malloc(IIO_MAX_NAME_LENGTH);
466                 ret = read_sysfs_string("name", trig_dev_name, trigger_name);
467                 free(trig_dev_name);
468                 if (ret < 0) {
469                         fprintf(stderr, "Failed to read trigger%d name from\n", trig_num);
470                         return ret;
471                 }
472                 printf("iio trigger number being used is %d\n", trig_num);
473         } else {
474                 if (!trigger_name) {
475                         /*
476                          * Build the trigger name. If it is device associated
477                          * its name is <device_name>_dev[n] where n matches
478                          * the device number found above.
479                          */
480                         ret = asprintf(&trigger_name,
481                                        "%s-dev%d", device_name, dev_num);
482                         if (ret < 0) {
483                                 ret = -ENOMEM;
484                                 goto error;
485                         }
486                 }
487 
488                 /* Look for this "-devN" trigger */
489                 trig_num = find_type_by_name(trigger_name, "trigger");
490                 if (trig_num < 0) {
491                         /* OK try the simpler "-trigger" suffix instead */
492                         free(trigger_name);
493                         ret = asprintf(&trigger_name,
494                                        "%s-trigger", device_name);
495                         if (ret < 0) {
496                                 ret = -ENOMEM;
497                                 goto error;
498                         }
499                 }
500 
501                 trig_num = find_type_by_name(trigger_name, "trigger");
502                 if (trig_num < 0) {
503                         fprintf(stderr, "Failed to find the trigger %s\n",
504                                 trigger_name);
505                         ret = trig_num;
506                         goto error;
507                 }
508 
509                 printf("iio trigger number being used is %d\n", trig_num);
510         }
511 
512         /*
513          * Parse the files in scan_elements to identify what channels are
514          * present
515          */
516         ret = build_channel_array(dev_dir_name, &channels, &num_channels);
517         if (ret) {
518                 fprintf(stderr, "Problem reading scan element information\n"
519                         "diag %s\n", dev_dir_name);
520                 goto error;
521         }
522         if (num_channels && autochannels == AUTOCHANNELS_ENABLED) {
523                 fprintf(stderr, "Auto-channels selected but some channels "
524                         "are already activated in sysfs\n");
525                 fprintf(stderr, "Proceeding without activating any channels\n");
526         }
527 
528         if (!num_channels && autochannels == AUTOCHANNELS_ENABLED) {
529                 fprintf(stderr,
530                         "No channels are enabled, enabling all channels\n");
531 
532                 ret = enable_disable_all_channels(dev_dir_name, 1);
533                 if (ret) {
534                         fprintf(stderr, "Failed to enable all channels\n");
535                         goto error;
536                 }
537 
538                 /* This flags that we need to disable the channels again */
539                 autochannels = AUTOCHANNELS_ACTIVE;
540 
541                 ret = build_channel_array(dev_dir_name, &channels,
542                                           &num_channels);
543                 if (ret) {
544                         fprintf(stderr, "Problem reading scan element "
545                                 "information\n"
546                                 "diag %s\n", dev_dir_name);
547                         goto error;
548                 }
549                 if (!num_channels) {
550                         fprintf(stderr, "Still no channels after "
551                                 "auto-enabling, giving up\n");
552                         goto error;
553                 }
554         }
555 
556         if (!num_channels && autochannels == AUTOCHANNELS_DISABLED) {
557                 fprintf(stderr,
558                         "No channels are enabled, we have nothing to scan.\n");
559                 fprintf(stderr, "Enable channels manually in "
560                         FORMAT_SCAN_ELEMENTS_DIR
561                         "/*_en or pass -a to autoenable channels and "
562                         "try again.\n", dev_dir_name);
563                 ret = -ENOENT;
564                 goto error;
565         }
566 
567         /*
568          * Construct the directory name for the associated buffer.
569          * As we know that the lis3l02dq has only one buffer this may
570          * be built rather than found.
571          */
572         ret = asprintf(&buf_dir_name,
573                        "%siio:device%d/buffer", iio_dir, dev_num);
574         if (ret < 0) {
575                 ret = -ENOMEM;
576                 goto error;
577         }
578 
579         if (!notrigger) {
580                 printf("%s %s\n", dev_dir_name, trigger_name);
581                 /*
582                  * Set the device trigger to be the data ready trigger found
583                  * above
584                  */
585                 ret = write_sysfs_string_and_verify("trigger/current_trigger",
586                                                     dev_dir_name,
587                                                     trigger_name);
588                 if (ret < 0) {
589                         fprintf(stderr,
590                                 "Failed to write current_trigger file\n");
591                         goto error;
592                 }
593         }
594 
595         /* Setup ring buffer parameters */
596         ret = write_sysfs_int("length", buf_dir_name, buf_len);
597         if (ret < 0)
598                 goto error;
599 
600         /* Enable the buffer */
601         ret = write_sysfs_int("enable", buf_dir_name, 1);
602         if (ret < 0) {
603                 fprintf(stderr,
604                         "Failed to enable buffer: %s\n", strerror(-ret));
605                 goto error;
606         }
607 
608         scan_size = size_from_channelarray(channels, num_channels);
609         data = malloc(scan_size * buf_len);
610         if (!data) {
611                 ret = -ENOMEM;
612                 goto error;
613         }
614 
615         ret = asprintf(&buffer_access, "/dev/iio:device%d", dev_num);
616         if (ret < 0) {
617                 ret = -ENOMEM;
618                 goto error;
619         }
620 
621         /* Attempt to open non blocking the access dev */
622         fp = open(buffer_access, O_RDONLY | O_NONBLOCK);
623         if (fp == -1) { /* TODO: If it isn't there make the node */
624                 ret = -errno;
625                 fprintf(stderr, "Failed to open %s\n", buffer_access);
626                 goto error;
627         }
628 
629         for (j = 0; j < num_loops; j++) {
630                 if (!noevents) {
631                         struct pollfd pfd = {
632                                 .fd = fp,
633                                 .events = POLLIN,
634                         };
635 
636                         ret = poll(&pfd, 1, -1);
637                         if (ret < 0) {
638                                 ret = -errno;
639                                 goto error;
640                         } else if (ret == 0) {
641                                 continue;
642                         }
643 
644                         toread = buf_len;
645                 } else {
646                         usleep(timedelay);
647                         toread = 64;
648                 }
649 
650                 read_size = read(fp, data, toread * scan_size);
651                 if (read_size < 0) {
652                         if (errno == EAGAIN) {
653                                 fprintf(stderr, "nothing available\n");
654                                 continue;
655                         } else {
656                                 break;
657                         }
658                 }
659                 for (i = 0; i < read_size / scan_size; i++)
660                         process_scan(data + scan_size * i, channels,
661                                      num_channels);
662         }
663 
664 error:
665         cleanup();
666 
667         if (fp >= 0 && close(fp) == -1)
668                 perror("Failed to close buffer");
669         free(buffer_access);
670         free(data);
671         free(buf_dir_name);
672         for (i = num_channels - 1; i >= 0; i--) {
673                 free(channels[i].name);
674                 free(channels[i].generic_name);
675         }
676         free(channels);
677         free(trigger_name);
678         free(device_name);
679         free(dev_dir_name);
680 
681         return ret;
682 }
683 

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