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 */
40enum 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 **/
54static 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
84static 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
101static 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
124static 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
147static 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 **/
183static 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
213static 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
253static 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
273static enum autochan autochannels = AUTOCHANNELS_DISABLED;
274static char *dev_dir_name = NULL;
275static char *buf_dir_name = NULL;
276static int buffer_idx = 0;
277static bool current_trigger_set = false;
278
279static 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
311static void sig_handler(int signum)
312{
313	fprintf(stderr, "Caught signal %d\n", signum);
314	cleanup();
315	exit(-signum);
316}
317
318static 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
333static 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
341int 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		ret = read_sysfs_string("name", trig_dev_name, trigger_name);
502		free(trig_dev_name);
503		if (ret < 0) {
504			fprintf(stderr, "Failed to read trigger%d name from\n", trig_num);
505			return ret;
506		}
507		printf("iio trigger number being used is %d\n", trig_num);
508	} else {
509		if (!trigger_name) {
510			/*
511			 * Build the trigger name. If it is device associated
512			 * its name is <device_name>_dev[n] where n matches
513			 * the device number found above.
514			 */
515			ret = asprintf(&trigger_name,
516				       "%s-dev%d", device_name, dev_num);
517			if (ret < 0) {
518				ret = -ENOMEM;
519				goto error;
520			}
521		}
522
523		/* Look for this "-devN" trigger */
524		trig_num = find_type_by_name(trigger_name, "trigger");
525		if (trig_num < 0) {
526			/* OK try the simpler "-trigger" suffix instead */
527			free(trigger_name);
528			ret = asprintf(&trigger_name,
529				       "%s-trigger", device_name);
530			if (ret < 0) {
531				ret = -ENOMEM;
532				goto error;
533			}
534		}
535
536		trig_num = find_type_by_name(trigger_name, "trigger");
537		if (trig_num < 0) {
538			fprintf(stderr, "Failed to find the trigger %s\n",
539				trigger_name);
540			ret = trig_num;
541			goto error;
542		}
543
544		printf("iio trigger number being used is %d\n", trig_num);
545	}
546
547	/*
548	 * Parse the files in scan_elements to identify what channels are
549	 * present
550	 */
551	ret = build_channel_array(dev_dir_name, buffer_idx, &channels, &num_channels);
552	if (ret) {
553		fprintf(stderr, "Problem reading scan element information\n"
554			"diag %s\n", dev_dir_name);
555		goto error;
556	}
557	if (num_channels && autochannels == AUTOCHANNELS_ENABLED &&
558	    !force_autochannels) {
559		fprintf(stderr, "Auto-channels selected but some channels "
560			"are already activated in sysfs\n");
561		fprintf(stderr, "Proceeding without activating any channels\n");
562	}
563
564	if ((!num_channels && autochannels == AUTOCHANNELS_ENABLED) ||
565	    (autochannels == AUTOCHANNELS_ENABLED && force_autochannels)) {
566		fprintf(stderr, "Enabling all channels\n");
567
568		ret = enable_disable_all_channels(dev_dir_name, buffer_idx, 1);
569		if (ret) {
570			fprintf(stderr, "Failed to enable all channels\n");
571			goto error;
572		}
573
574		/* This flags that we need to disable the channels again */
575		autochannels = AUTOCHANNELS_ACTIVE;
576
577		ret = build_channel_array(dev_dir_name, buffer_idx, &channels,
578					  &num_channels);
579		if (ret) {
580			fprintf(stderr, "Problem reading scan element "
581				"information\n"
582				"diag %s\n", dev_dir_name);
583			goto error;
584		}
585		if (!num_channels) {
586			fprintf(stderr, "Still no channels after "
587				"auto-enabling, giving up\n");
588			goto error;
589		}
590	}
591
592	if (!num_channels && autochannels == AUTOCHANNELS_DISABLED) {
593		fprintf(stderr,
594			"No channels are enabled, we have nothing to scan.\n");
595		fprintf(stderr, "Enable channels manually in "
596			FORMAT_SCAN_ELEMENTS_DIR
597			"/*_en or pass -a to autoenable channels and "
598			"try again.\n", dev_dir_name, buffer_idx);
599		ret = -ENOENT;
600		goto error;
601	}
602
603	/*
604	 * Construct the directory name for the associated buffer.
605	 * As we know that the lis3l02dq has only one buffer this may
606	 * be built rather than found.
607	 */
608	ret = asprintf(&buf_dir_name,
609		       "%siio:device%d/buffer%d", iio_dir, dev_num, buffer_idx);
610	if (ret < 0) {
611		ret = -ENOMEM;
612		goto error;
613	}
614
615	if (stat(buf_dir_name, &st)) {
616		fprintf(stderr, "Could not stat() '%s', got error %d: %s\n",
617			buf_dir_name, errno, strerror(errno));
618		ret = -errno;
619		goto error;
620	}
621
622	if (!S_ISDIR(st.st_mode)) {
623		fprintf(stderr, "File '%s' is not a directory\n", buf_dir_name);
624		ret = -EFAULT;
625		goto error;
626	}
627
628	if (!notrigger) {
629		printf("%s %s\n", dev_dir_name, trigger_name);
630		/*
631		 * Set the device trigger to be the data ready trigger found
632		 * above
633		 */
634		ret = write_sysfs_string_and_verify("trigger/current_trigger",
635						    dev_dir_name,
636						    trigger_name);
637		if (ret < 0) {
638			fprintf(stderr,
639				"Failed to write current_trigger file\n");
640			goto error;
641		}
642	}
643
644	ret = asprintf(&buffer_access, "/dev/iio:device%d", dev_num);
645	if (ret < 0) {
646		ret = -ENOMEM;
647		goto error;
648	}
649
650	/* Attempt to open non blocking the access dev */
651	fd = open(buffer_access, O_RDONLY | O_NONBLOCK);
652	if (fd == -1) { /* TODO: If it isn't there make the node */
653		ret = -errno;
654		fprintf(stderr, "Failed to open %s\n", buffer_access);
655		goto error;
656	}
657
658	/* specify for which buffer index we want an FD */
659	buf_fd = buffer_idx;
660
661	ret = ioctl(fd, IIO_BUFFER_GET_FD_IOCTL, &buf_fd);
662	if (ret == -1 || buf_fd == -1) {
663		ret = -errno;
664		if (ret == -ENODEV || ret == -EINVAL)
665			fprintf(stderr,
666				"Device does not have this many buffers\n");
667		else
668			fprintf(stderr, "Failed to retrieve buffer fd\n");
669
670		goto error;
671	}
672
673	/* Setup ring buffer parameters */
674	ret = write_sysfs_int("length", buf_dir_name, buf_len);
675	if (ret < 0)
676		goto error;
677
678	/* Enable the buffer */
679	ret = write_sysfs_int("enable", buf_dir_name, 1);
680	if (ret < 0) {
681		fprintf(stderr,
682			"Failed to enable buffer '%s': %s\n",
683			buf_dir_name, strerror(-ret));
684		goto error;
685	}
686
687	scan_size = size_from_channelarray(channels, num_channels);
688
689	size_t total_buf_len = scan_size * buf_len;
690
691	if (scan_size > 0 && total_buf_len / scan_size != buf_len) {
692		ret = -EFAULT;
693		perror("Integer overflow happened when calculate scan_size * buf_len");
694		goto error;
695	}
696
697	data = malloc(total_buf_len);
698	if (!data) {
699		ret = -ENOMEM;
700		goto error;
701	}
702
703	/**
704	 * This check is being done here for sanity reasons, however it
705	 * should be omitted under normal operation.
706	 * If this is buffer0, we check that we get EBUSY after this point.
707	 */
708	if (buffer_idx == 0) {
709		errno = 0;
710		read_size = read(fd, data, 1);
711		if (read_size > -1 || errno != EBUSY) {
712			ret = -EFAULT;
713			perror("Reading from '%s' should not be possible after ioctl()");
714			goto error;
715		}
716	}
717
718	/* close now the main chardev FD and let the buffer FD work */
719	if (close(fd) == -1)
720		perror("Failed to close character device file");
721	fd = -1;
722
723	for (j = 0; j < num_loops || num_loops < 0; j++) {
724		if (!noevents) {
725			struct pollfd pfd = {
726				.fd = buf_fd,
727				.events = POLLIN,
728			};
729
730			ret = poll(&pfd, 1, -1);
731			if (ret < 0) {
732				ret = -errno;
733				goto error;
734			} else if (ret == 0) {
735				continue;
736			}
737
738		} else {
739			usleep(timedelay);
740		}
741
742		toread = buf_len;
743
744		read_size = read(buf_fd, data, toread * scan_size);
745		if (read_size < 0) {
746			if (errno == EAGAIN) {
747				fprintf(stderr, "nothing available\n");
748				continue;
749			} else {
750				break;
751			}
752		}
753		for (i = 0; i < read_size / scan_size; i++)
754			process_scan(data + scan_size * i, channels,
755				     num_channels);
756	}
757
758error:
759	cleanup();
760
761	if (fd >= 0 && close(fd) == -1)
762		perror("Failed to close character device");
763	if (buf_fd >= 0 && close(buf_fd) == -1)
764		perror("Failed to close buffer");
765	free(buffer_access);
766	free(data);
767	free(buf_dir_name);
768	for (i = num_channels - 1; i >= 0; i--) {
769		free(channels[i].name);
770		free(channels[i].generic_name);
771	}
772	free(channels);
773	free(trigger_name);
774	free(device_name);
775	free(dev_dir_name);
776
777	return ret;
778}
779