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
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