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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                 "  -A         Force-activate ALL channels\n"
251                 "  -c <n>     Do n conversions\n"
252                 "  -e         Disable wait for event (new data)\n"
253                 "  -g         Use trigger-less mode\n"
254                 "  -l <n>     Set buffer length to n samples\n"
255                 "  --device-name -n <name>\n"
256                 "  --device-num -N <num>\n"
257                 "        Set device by name or number (mandatory)\n"
258                 "  --trigger-name -t <name>\n"
259                 "  --trigger-num -T <num>\n"
260                 "        Set trigger by name or number\n"
261                 "  -w <n>     Set delay between reads in us (event-less mode)\n");
262 }
263 
264 enum autochan autochannels = AUTOCHANNELS_DISABLED;
265 char *dev_dir_name = NULL;
266 char *buf_dir_name = NULL;
267 bool current_trigger_set = false;
268 
269 void cleanup(void)
270 {
271         int ret;
272 
273         /* Disable trigger */
274         if (dev_dir_name && current_trigger_set) {
275                 /* Disconnect the trigger - just write a dummy name. */
276                 ret = write_sysfs_string("trigger/current_trigger",
277                                          dev_dir_name, "NULL");
278                 if (ret < 0)
279                         fprintf(stderr, "Failed to disable trigger: %s\n",
280                                 strerror(-ret));
281                 current_trigger_set = false;
282         }
283 
284         /* Disable buffer */
285         if (buf_dir_name) {
286                 ret = write_sysfs_int("enable", buf_dir_name, 0);
287                 if (ret < 0)
288                         fprintf(stderr, "Failed to disable buffer: %s\n",
289                                 strerror(-ret));
290         }
291 
292         /* Disable channels if auto-enabled */
293         if (dev_dir_name && autochannels == AUTOCHANNELS_ACTIVE) {
294                 ret = enable_disable_all_channels(dev_dir_name, 0);
295                 if (ret)
296                         fprintf(stderr, "Failed to disable all channels\n");
297                 autochannels = AUTOCHANNELS_DISABLED;
298         }
299 }
300 
301 void sig_handler(int signum)
302 {
303         fprintf(stderr, "Caught signal %d\n", signum);
304         cleanup();
305         exit(-signum);
306 }
307 
308 void register_cleanup(void)
309 {
310         struct sigaction sa = { .sa_handler = sig_handler };
311         const int signums[] = { SIGINT, SIGTERM, SIGABRT };
312         int ret, i;
313 
314         for (i = 0; i < ARRAY_SIZE(signums); ++i) {
315                 ret = sigaction(signums[i], &sa, NULL);
316                 if (ret) {
317                         perror("Failed to register signal handler");
318                         exit(-1);
319                 }
320         }
321 }
322 
323 static const struct option longopts[] = {
324         { "device-name",        1, 0, 'n' },
325         { "device-num",         1, 0, 'N' },
326         { "trigger-name",       1, 0, 't' },
327         { "trigger-num",        1, 0, 'T' },
328         { },
329 };
330 
331 int main(int argc, char **argv)
332 {
333         unsigned long num_loops = 2;
334         unsigned long timedelay = 1000000;
335         unsigned long buf_len = 128;
336 
337         int ret, c, i, j, toread;
338         int fp = -1;
339 
340         int num_channels = 0;
341         char *trigger_name = NULL, *device_name = NULL;
342 
343         char *data = NULL;
344         ssize_t read_size;
345         int dev_num = -1, trig_num = -1;
346         char *buffer_access = NULL;
347         int scan_size;
348         int noevents = 0;
349         int notrigger = 0;
350         char *dummy;
351         bool force_autochannels = false;
352 
353         struct iio_channel_info *channels = NULL;
354 
355         register_cleanup();
356 
357         while ((c = getopt_long(argc, argv, "aAc:egl:n:N:t:T:w:?", longopts,
358                                 NULL)) != -1) {
359                 switch (c) {
360                 case 'a':
361                         autochannels = AUTOCHANNELS_ENABLED;
362                         break;
363                 case 'A':
364                         autochannels = AUTOCHANNELS_ENABLED;
365                         force_autochannels = true;
366                         break;  
367                 case 'c':
368                         errno = 0;
369                         num_loops = strtoul(optarg, &dummy, 10);
370                         if (errno) {
371                                 ret = -errno;
372                                 goto error;
373                         }
374 
375                         break;
376                 case 'e':
377                         noevents = 1;
378                         break;
379                 case 'g':
380                         notrigger = 1;
381                         break;
382                 case 'l':
383                         errno = 0;
384                         buf_len = strtoul(optarg, &dummy, 10);
385                         if (errno) {
386                                 ret = -errno;
387                                 goto error;
388                         }
389 
390                         break;
391                 case 'n':
392                         device_name = strdup(optarg);
393                         break;
394                 case 'N':
395                         errno = 0;
396                         dev_num = strtoul(optarg, &dummy, 10);
397                         if (errno) {
398                                 ret = -errno;
399                                 goto error;
400                         }
401                         break;
402                 case 't':
403                         trigger_name = strdup(optarg);
404                         break;
405                 case 'T':
406                         errno = 0;
407                         trig_num = strtoul(optarg, &dummy, 10);
408                         if (errno)
409                                 return -errno;
410                         break;
411                 case 'w':
412                         errno = 0;
413                         timedelay = strtoul(optarg, &dummy, 10);
414                         if (errno) {
415                                 ret = -errno;
416                                 goto error;
417                         }
418                         break;
419                 case '?':
420                         print_usage();
421                         ret = -1;
422                         goto error;
423                 }
424         }
425 
426         /* Find the device requested */
427         if (dev_num < 0 && !device_name) {
428                 fprintf(stderr, "Device not set\n");
429                 print_usage();
430                 ret = -1;
431                 goto error;
432         } else if (dev_num >= 0 && device_name) {
433                 fprintf(stderr, "Only one of --device-num or --device-name needs to be set\n");
434                 print_usage();
435                 ret = -1;
436                 goto error;
437         } else if (dev_num < 0) {
438                 dev_num = find_type_by_name(device_name, "iio:device");
439                 if (dev_num < 0) {
440                         fprintf(stderr, "Failed to find the %s\n", device_name);
441                         ret = dev_num;
442                         goto error;
443                 }
444         }
445         printf("iio device number being used is %d\n", dev_num);
446 
447         ret = asprintf(&dev_dir_name, "%siio:device%d", iio_dir, dev_num);
448         if (ret < 0)
449                 return -ENOMEM;
450         /* Fetch device_name if specified by number */
451         if (!device_name) {
452                 device_name = malloc(IIO_MAX_NAME_LENGTH);
453                 if (!device_name) {
454                         ret = -ENOMEM;
455                         goto error;
456                 }
457                 ret = read_sysfs_string("name", dev_dir_name, device_name);
458                 if (ret < 0) {
459                         fprintf(stderr, "Failed to read name of device %d\n", dev_num);
460                         goto error;
461                 }
462         }
463 
464         if (notrigger) {
465                 printf("trigger-less mode selected\n");
466         } else if (trig_num >= 0) {
467                 char *trig_dev_name;
468                 ret = asprintf(&trig_dev_name, "%strigger%d", iio_dir, trig_num);
469                 if (ret < 0) {
470                         return -ENOMEM;
471                 }
472                 trigger_name = malloc(IIO_MAX_NAME_LENGTH);
473                 ret = read_sysfs_string("name", trig_dev_name, trigger_name);
474                 free(trig_dev_name);
475                 if (ret < 0) {
476                         fprintf(stderr, "Failed to read trigger%d name from\n", trig_num);
477                         return ret;
478                 }
479                 printf("iio trigger number being used is %d\n", trig_num);
480         } else {
481                 if (!trigger_name) {
482                         /*
483                          * Build the trigger name. If it is device associated
484                          * its name is <device_name>_dev[n] where n matches
485                          * the device number found above.
486                          */
487                         ret = asprintf(&trigger_name,
488                                        "%s-dev%d", device_name, dev_num);
489                         if (ret < 0) {
490                                 ret = -ENOMEM;
491                                 goto error;
492                         }
493                 }
494 
495                 /* Look for this "-devN" trigger */
496                 trig_num = find_type_by_name(trigger_name, "trigger");
497                 if (trig_num < 0) {
498                         /* OK try the simpler "-trigger" suffix instead */
499                         free(trigger_name);
500                         ret = asprintf(&trigger_name,
501                                        "%s-trigger", device_name);
502                         if (ret < 0) {
503                                 ret = -ENOMEM;
504                                 goto error;
505                         }
506                 }
507 
508                 trig_num = find_type_by_name(trigger_name, "trigger");
509                 if (trig_num < 0) {
510                         fprintf(stderr, "Failed to find the trigger %s\n",
511                                 trigger_name);
512                         ret = trig_num;
513                         goto error;
514                 }
515 
516                 printf("iio trigger number being used is %d\n", trig_num);
517         }
518 
519         /*
520          * Parse the files in scan_elements to identify what channels are
521          * present
522          */
523         ret = build_channel_array(dev_dir_name, &channels, &num_channels);
524         if (ret) {
525                 fprintf(stderr, "Problem reading scan element information\n"
526                         "diag %s\n", dev_dir_name);
527                 goto error;
528         }
529         if (num_channels && autochannels == AUTOCHANNELS_ENABLED &&
530             !force_autochannels) {
531                 fprintf(stderr, "Auto-channels selected but some channels "
532                         "are already activated in sysfs\n");
533                 fprintf(stderr, "Proceeding without activating any channels\n");
534         }
535 
536         if ((!num_channels && autochannels == AUTOCHANNELS_ENABLED) ||
537             (autochannels == AUTOCHANNELS_ENABLED && force_autochannels)) {
538                 fprintf(stderr, "Enabling all channels\n");
539 
540                 ret = enable_disable_all_channels(dev_dir_name, 1);
541                 if (ret) {
542                         fprintf(stderr, "Failed to enable all channels\n");
543                         goto error;
544                 }
545 
546                 /* This flags that we need to disable the channels again */
547                 autochannels = AUTOCHANNELS_ACTIVE;
548 
549                 ret = build_channel_array(dev_dir_name, &channels,
550                                           &num_channels);
551                 if (ret) {
552                         fprintf(stderr, "Problem reading scan element "
553                                 "information\n"
554                                 "diag %s\n", dev_dir_name);
555                         goto error;
556                 }
557                 if (!num_channels) {
558                         fprintf(stderr, "Still no channels after "
559                                 "auto-enabling, giving up\n");
560                         goto error;
561                 }
562         }
563 
564         if (!num_channels && autochannels == AUTOCHANNELS_DISABLED) {
565                 fprintf(stderr,
566                         "No channels are enabled, we have nothing to scan.\n");
567                 fprintf(stderr, "Enable channels manually in "
568                         FORMAT_SCAN_ELEMENTS_DIR
569                         "/*_en or pass -a to autoenable channels and "
570                         "try again.\n", dev_dir_name);
571                 ret = -ENOENT;
572                 goto error;
573         }
574 
575         /*
576          * Construct the directory name for the associated buffer.
577          * As we know that the lis3l02dq has only one buffer this may
578          * be built rather than found.
579          */
580         ret = asprintf(&buf_dir_name,
581                        "%siio:device%d/buffer", iio_dir, dev_num);
582         if (ret < 0) {
583                 ret = -ENOMEM;
584                 goto error;
585         }
586 
587         if (!notrigger) {
588                 printf("%s %s\n", dev_dir_name, trigger_name);
589                 /*
590                  * Set the device trigger to be the data ready trigger found
591                  * above
592                  */
593                 ret = write_sysfs_string_and_verify("trigger/current_trigger",
594                                                     dev_dir_name,
595                                                     trigger_name);
596                 if (ret < 0) {
597                         fprintf(stderr,
598                                 "Failed to write current_trigger file\n");
599                         goto error;
600                 }
601         }
602 
603         /* Setup ring buffer parameters */
604         ret = write_sysfs_int("length", buf_dir_name, buf_len);
605         if (ret < 0)
606                 goto error;
607 
608         /* Enable the buffer */
609         ret = write_sysfs_int("enable", buf_dir_name, 1);
610         if (ret < 0) {
611                 fprintf(stderr,
612                         "Failed to enable buffer: %s\n", strerror(-ret));
613                 goto error;
614         }
615 
616         scan_size = size_from_channelarray(channels, num_channels);
617         data = malloc(scan_size * buf_len);
618         if (!data) {
619                 ret = -ENOMEM;
620                 goto error;
621         }
622 
623         ret = asprintf(&buffer_access, "/dev/iio:device%d", dev_num);
624         if (ret < 0) {
625                 ret = -ENOMEM;
626                 goto error;
627         }
628 
629         /* Attempt to open non blocking the access dev */
630         fp = open(buffer_access, O_RDONLY | O_NONBLOCK);
631         if (fp == -1) { /* TODO: If it isn't there make the node */
632                 ret = -errno;
633                 fprintf(stderr, "Failed to open %s\n", buffer_access);
634                 goto error;
635         }
636 
637         for (j = 0; j < num_loops; j++) {
638                 if (!noevents) {
639                         struct pollfd pfd = {
640                                 .fd = fp,
641                                 .events = POLLIN,
642                         };
643 
644                         ret = poll(&pfd, 1, -1);
645                         if (ret < 0) {
646                                 ret = -errno;
647                                 goto error;
648                         } else if (ret == 0) {
649                                 continue;
650                         }
651 
652                         toread = buf_len;
653                 } else {
654                         usleep(timedelay);
655                         toread = 64;
656                 }
657 
658                 read_size = read(fp, data, toread * scan_size);
659                 if (read_size < 0) {
660                         if (errno == EAGAIN) {
661                                 fprintf(stderr, "nothing available\n");
662                                 continue;
663                         } else {
664                                 break;
665                         }
666                 }
667                 for (i = 0; i < read_size / scan_size; i++)
668                         process_scan(data + scan_size * i, channels,
669                                      num_channels);
670         }
671 
672 error:
673         cleanup();
674 
675         if (fp >= 0 && close(fp) == -1)
676                 perror("Failed to close buffer");
677         free(buffer_access);
678         free(data);
679         free(buf_dir_name);
680         for (i = num_channels - 1; i >= 0; i--) {
681                 free(channels[i].name);
682                 free(channels[i].generic_name);
683         }
684         free(channels);
685         free(trigger_name);
686         free(device_name);
687         free(dev_dir_name);
688 
689         return ret;
690 }
691 

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