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1// SPDX-License-Identifier: GPL-2.0-only
2/* The industrial I/O core
3 *
4 * Copyright (c) 2008 Jonathan Cameron
5 *
6 * Handling of buffer allocation / resizing.
7 *
8 * Things to look at here.
9 * - Better memory allocation techniques?
10 * - Alternative access techniques?
11 */
12#include <linux/kernel.h>
13#include <linux/export.h>
14#include <linux/device.h>
15#include <linux/fs.h>
16#include <linux/cdev.h>
17#include <linux/slab.h>
18#include <linux/poll.h>
19#include <linux/sched/signal.h>
20
21#include <linux/iio/iio.h>
22#include <linux/iio/iio-opaque.h>
23#include "iio_core.h"
24#include "iio_core_trigger.h"
25#include <linux/iio/sysfs.h>
26#include <linux/iio/buffer.h>
27#include <linux/iio/buffer_impl.h>
28
29static const char * const iio_endian_prefix[] = {
30 [IIO_BE] = "be",
31 [IIO_LE] = "le",
32};
33
34static bool iio_buffer_is_active(struct iio_buffer *buf)
35{
36 return !list_empty(&buf->buffer_list);
37}
38
39static size_t iio_buffer_data_available(struct iio_buffer *buf)
40{
41 return buf->access->data_available(buf);
42}
43
44static int iio_buffer_flush_hwfifo(struct iio_dev *indio_dev,
45 struct iio_buffer *buf, size_t required)
46{
47 if (!indio_dev->info->hwfifo_flush_to_buffer)
48 return -ENODEV;
49
50 return indio_dev->info->hwfifo_flush_to_buffer(indio_dev, required);
51}
52
53static bool iio_buffer_ready(struct iio_dev *indio_dev, struct iio_buffer *buf,
54 size_t to_wait, int to_flush)
55{
56 size_t avail;
57 int flushed = 0;
58
59 /* wakeup if the device was unregistered */
60 if (!indio_dev->info)
61 return true;
62
63 /* drain the buffer if it was disabled */
64 if (!iio_buffer_is_active(buf)) {
65 to_wait = min_t(size_t, to_wait, 1);
66 to_flush = 0;
67 }
68
69 avail = iio_buffer_data_available(buf);
70
71 if (avail >= to_wait) {
72 /* force a flush for non-blocking reads */
73 if (!to_wait && avail < to_flush)
74 iio_buffer_flush_hwfifo(indio_dev, buf,
75 to_flush - avail);
76 return true;
77 }
78
79 if (to_flush)
80 flushed = iio_buffer_flush_hwfifo(indio_dev, buf,
81 to_wait - avail);
82 if (flushed <= 0)
83 return false;
84
85 if (avail + flushed >= to_wait)
86 return true;
87
88 return false;
89}
90
91/**
92 * iio_buffer_read_outer() - chrdev read for buffer access
93 * @filp: File structure pointer for the char device
94 * @buf: Destination buffer for iio buffer read
95 * @n: First n bytes to read
96 * @f_ps: Long offset provided by the user as a seek position
97 *
98 * This function relies on all buffer implementations having an
99 * iio_buffer as their first element.
100 *
101 * Return: negative values corresponding to error codes or ret != 0
102 * for ending the reading activity
103 **/
104ssize_t iio_buffer_read_outer(struct file *filp, char __user *buf,
105 size_t n, loff_t *f_ps)
106{
107 struct iio_dev *indio_dev = filp->private_data;
108 struct iio_buffer *rb = indio_dev->buffer;
109 DEFINE_WAIT_FUNC(wait, woken_wake_function);
110 size_t datum_size;
111 size_t to_wait;
112 int ret = 0;
113
114 if (!indio_dev->info)
115 return -ENODEV;
116
117 if (!rb || !rb->access->read)
118 return -EINVAL;
119
120 datum_size = rb->bytes_per_datum;
121
122 /*
123 * If datum_size is 0 there will never be anything to read from the
124 * buffer, so signal end of file now.
125 */
126 if (!datum_size)
127 return 0;
128
129 if (filp->f_flags & O_NONBLOCK)
130 to_wait = 0;
131 else
132 to_wait = min_t(size_t, n / datum_size, rb->watermark);
133
134 add_wait_queue(&rb->pollq, &wait);
135 do {
136 if (!indio_dev->info) {
137 ret = -ENODEV;
138 break;
139 }
140
141 if (!iio_buffer_ready(indio_dev, rb, to_wait, n / datum_size)) {
142 if (signal_pending(current)) {
143 ret = -ERESTARTSYS;
144 break;
145 }
146
147 wait_woken(&wait, TASK_INTERRUPTIBLE,
148 MAX_SCHEDULE_TIMEOUT);
149 continue;
150 }
151
152 ret = rb->access->read(rb, n, buf);
153 if (ret == 0 && (filp->f_flags & O_NONBLOCK))
154 ret = -EAGAIN;
155 } while (ret == 0);
156 remove_wait_queue(&rb->pollq, &wait);
157
158 return ret;
159}
160
161/**
162 * iio_buffer_poll() - poll the buffer to find out if it has data
163 * @filp: File structure pointer for device access
164 * @wait: Poll table structure pointer for which the driver adds
165 * a wait queue
166 *
167 * Return: (EPOLLIN | EPOLLRDNORM) if data is available for reading
168 * or 0 for other cases
169 */
170__poll_t iio_buffer_poll(struct file *filp,
171 struct poll_table_struct *wait)
172{
173 struct iio_dev *indio_dev = filp->private_data;
174 struct iio_buffer *rb = indio_dev->buffer;
175
176 if (!indio_dev->info || rb == NULL)
177 return 0;
178
179 poll_wait(filp, &rb->pollq, wait);
180 if (iio_buffer_ready(indio_dev, rb, rb->watermark, 0))
181 return EPOLLIN | EPOLLRDNORM;
182 return 0;
183}
184
185/**
186 * iio_buffer_wakeup_poll - Wakes up the buffer waitqueue
187 * @indio_dev: The IIO device
188 *
189 * Wakes up the event waitqueue used for poll(). Should usually
190 * be called when the device is unregistered.
191 */
192void iio_buffer_wakeup_poll(struct iio_dev *indio_dev)
193{
194 struct iio_buffer *buffer = indio_dev->buffer;
195
196 if (!buffer)
197 return;
198
199 wake_up(&buffer->pollq);
200}
201
202void iio_buffer_init(struct iio_buffer *buffer)
203{
204 INIT_LIST_HEAD(&buffer->demux_list);
205 INIT_LIST_HEAD(&buffer->buffer_list);
206 init_waitqueue_head(&buffer->pollq);
207 kref_init(&buffer->ref);
208 if (!buffer->watermark)
209 buffer->watermark = 1;
210}
211EXPORT_SYMBOL(iio_buffer_init);
212
213/**
214 * iio_buffer_set_attrs - Set buffer specific attributes
215 * @buffer: The buffer for which we are setting attributes
216 * @attrs: Pointer to a null terminated list of pointers to attributes
217 */
218void iio_buffer_set_attrs(struct iio_buffer *buffer,
219 const struct attribute **attrs)
220{
221 buffer->attrs = attrs;
222}
223EXPORT_SYMBOL_GPL(iio_buffer_set_attrs);
224
225static ssize_t iio_show_scan_index(struct device *dev,
226 struct device_attribute *attr,
227 char *buf)
228{
229 return sprintf(buf, "%u\n", to_iio_dev_attr(attr)->c->scan_index);
230}
231
232static ssize_t iio_show_fixed_type(struct device *dev,
233 struct device_attribute *attr,
234 char *buf)
235{
236 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
237 u8 type = this_attr->c->scan_type.endianness;
238
239 if (type == IIO_CPU) {
240#ifdef __LITTLE_ENDIAN
241 type = IIO_LE;
242#else
243 type = IIO_BE;
244#endif
245 }
246 if (this_attr->c->scan_type.repeat > 1)
247 return sprintf(buf, "%s:%c%d/%dX%d>>%u\n",
248 iio_endian_prefix[type],
249 this_attr->c->scan_type.sign,
250 this_attr->c->scan_type.realbits,
251 this_attr->c->scan_type.storagebits,
252 this_attr->c->scan_type.repeat,
253 this_attr->c->scan_type.shift);
254 else
255 return sprintf(buf, "%s:%c%d/%d>>%u\n",
256 iio_endian_prefix[type],
257 this_attr->c->scan_type.sign,
258 this_attr->c->scan_type.realbits,
259 this_attr->c->scan_type.storagebits,
260 this_attr->c->scan_type.shift);
261}
262
263static ssize_t iio_scan_el_show(struct device *dev,
264 struct device_attribute *attr,
265 char *buf)
266{
267 int ret;
268 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
269 struct iio_buffer *buffer = indio_dev->buffer;
270
271 /* Ensure ret is 0 or 1. */
272 ret = !!test_bit(to_iio_dev_attr(attr)->address,
273 buffer->scan_mask);
274
275 return sprintf(buf, "%d\n", ret);
276}
277
278/* Note NULL used as error indicator as it doesn't make sense. */
279static const unsigned long *iio_scan_mask_match(const unsigned long *av_masks,
280 unsigned int masklength,
281 const unsigned long *mask,
282 bool strict)
283{
284 if (bitmap_empty(mask, masklength))
285 return NULL;
286 while (*av_masks) {
287 if (strict) {
288 if (bitmap_equal(mask, av_masks, masklength))
289 return av_masks;
290 } else {
291 if (bitmap_subset(mask, av_masks, masklength))
292 return av_masks;
293 }
294 av_masks += BITS_TO_LONGS(masklength);
295 }
296 return NULL;
297}
298
299static bool iio_validate_scan_mask(struct iio_dev *indio_dev,
300 const unsigned long *mask)
301{
302 if (!indio_dev->setup_ops->validate_scan_mask)
303 return true;
304
305 return indio_dev->setup_ops->validate_scan_mask(indio_dev, mask);
306}
307
308/**
309 * iio_scan_mask_set() - set particular bit in the scan mask
310 * @indio_dev: the iio device
311 * @buffer: the buffer whose scan mask we are interested in
312 * @bit: the bit to be set.
313 *
314 * Note that at this point we have no way of knowing what other
315 * buffers might request, hence this code only verifies that the
316 * individual buffers request is plausible.
317 */
318static int iio_scan_mask_set(struct iio_dev *indio_dev,
319 struct iio_buffer *buffer, int bit)
320{
321 const unsigned long *mask;
322 unsigned long *trialmask;
323
324 trialmask = bitmap_zalloc(indio_dev->masklength, GFP_KERNEL);
325 if (trialmask == NULL)
326 return -ENOMEM;
327 if (!indio_dev->masklength) {
328 WARN(1, "Trying to set scanmask prior to registering buffer\n");
329 goto err_invalid_mask;
330 }
331 bitmap_copy(trialmask, buffer->scan_mask, indio_dev->masklength);
332 set_bit(bit, trialmask);
333
334 if (!iio_validate_scan_mask(indio_dev, trialmask))
335 goto err_invalid_mask;
336
337 if (indio_dev->available_scan_masks) {
338 mask = iio_scan_mask_match(indio_dev->available_scan_masks,
339 indio_dev->masklength,
340 trialmask, false);
341 if (!mask)
342 goto err_invalid_mask;
343 }
344 bitmap_copy(buffer->scan_mask, trialmask, indio_dev->masklength);
345
346 bitmap_free(trialmask);
347
348 return 0;
349
350err_invalid_mask:
351 bitmap_free(trialmask);
352 return -EINVAL;
353}
354
355static int iio_scan_mask_clear(struct iio_buffer *buffer, int bit)
356{
357 clear_bit(bit, buffer->scan_mask);
358 return 0;
359}
360
361static int iio_scan_mask_query(struct iio_dev *indio_dev,
362 struct iio_buffer *buffer, int bit)
363{
364 if (bit > indio_dev->masklength)
365 return -EINVAL;
366
367 if (!buffer->scan_mask)
368 return 0;
369
370 /* Ensure return value is 0 or 1. */
371 return !!test_bit(bit, buffer->scan_mask);
372};
373
374static ssize_t iio_scan_el_store(struct device *dev,
375 struct device_attribute *attr,
376 const char *buf,
377 size_t len)
378{
379 int ret;
380 bool state;
381 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
382 struct iio_buffer *buffer = indio_dev->buffer;
383 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
384
385 ret = strtobool(buf, &state);
386 if (ret < 0)
387 return ret;
388 mutex_lock(&indio_dev->mlock);
389 if (iio_buffer_is_active(buffer)) {
390 ret = -EBUSY;
391 goto error_ret;
392 }
393 ret = iio_scan_mask_query(indio_dev, buffer, this_attr->address);
394 if (ret < 0)
395 goto error_ret;
396 if (!state && ret) {
397 ret = iio_scan_mask_clear(buffer, this_attr->address);
398 if (ret)
399 goto error_ret;
400 } else if (state && !ret) {
401 ret = iio_scan_mask_set(indio_dev, buffer, this_attr->address);
402 if (ret)
403 goto error_ret;
404 }
405
406error_ret:
407 mutex_unlock(&indio_dev->mlock);
408
409 return ret < 0 ? ret : len;
410
411}
412
413static ssize_t iio_scan_el_ts_show(struct device *dev,
414 struct device_attribute *attr,
415 char *buf)
416{
417 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
418 struct iio_buffer *buffer = indio_dev->buffer;
419
420 return sprintf(buf, "%d\n", buffer->scan_timestamp);
421}
422
423static ssize_t iio_scan_el_ts_store(struct device *dev,
424 struct device_attribute *attr,
425 const char *buf,
426 size_t len)
427{
428 int ret;
429 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
430 struct iio_buffer *buffer = indio_dev->buffer;
431 bool state;
432
433 ret = strtobool(buf, &state);
434 if (ret < 0)
435 return ret;
436
437 mutex_lock(&indio_dev->mlock);
438 if (iio_buffer_is_active(buffer)) {
439 ret = -EBUSY;
440 goto error_ret;
441 }
442 buffer->scan_timestamp = state;
443error_ret:
444 mutex_unlock(&indio_dev->mlock);
445
446 return ret ? ret : len;
447}
448
449static int iio_buffer_add_channel_sysfs(struct iio_dev *indio_dev,
450 struct iio_buffer *buffer,
451 const struct iio_chan_spec *chan)
452{
453 int ret, attrcount = 0;
454
455 ret = __iio_add_chan_devattr("index",
456 chan,
457 &iio_show_scan_index,
458 NULL,
459 0,
460 IIO_SEPARATE,
461 &indio_dev->dev,
462 &buffer->scan_el_dev_attr_list);
463 if (ret)
464 return ret;
465 attrcount++;
466 ret = __iio_add_chan_devattr("type",
467 chan,
468 &iio_show_fixed_type,
469 NULL,
470 0,
471 0,
472 &indio_dev->dev,
473 &buffer->scan_el_dev_attr_list);
474 if (ret)
475 return ret;
476 attrcount++;
477 if (chan->type != IIO_TIMESTAMP)
478 ret = __iio_add_chan_devattr("en",
479 chan,
480 &iio_scan_el_show,
481 &iio_scan_el_store,
482 chan->scan_index,
483 0,
484 &indio_dev->dev,
485 &buffer->scan_el_dev_attr_list);
486 else
487 ret = __iio_add_chan_devattr("en",
488 chan,
489 &iio_scan_el_ts_show,
490 &iio_scan_el_ts_store,
491 chan->scan_index,
492 0,
493 &indio_dev->dev,
494 &buffer->scan_el_dev_attr_list);
495 if (ret)
496 return ret;
497 attrcount++;
498 ret = attrcount;
499 return ret;
500}
501
502static ssize_t iio_buffer_read_length(struct device *dev,
503 struct device_attribute *attr,
504 char *buf)
505{
506 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
507 struct iio_buffer *buffer = indio_dev->buffer;
508
509 return sprintf(buf, "%d\n", buffer->length);
510}
511
512static ssize_t iio_buffer_write_length(struct device *dev,
513 struct device_attribute *attr,
514 const char *buf, size_t len)
515{
516 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
517 struct iio_buffer *buffer = indio_dev->buffer;
518 unsigned int val;
519 int ret;
520
521 ret = kstrtouint(buf, 10, &val);
522 if (ret)
523 return ret;
524
525 if (val == buffer->length)
526 return len;
527
528 mutex_lock(&indio_dev->mlock);
529 if (iio_buffer_is_active(buffer)) {
530 ret = -EBUSY;
531 } else {
532 buffer->access->set_length(buffer, val);
533 ret = 0;
534 }
535 if (ret)
536 goto out;
537 if (buffer->length && buffer->length < buffer->watermark)
538 buffer->watermark = buffer->length;
539out:
540 mutex_unlock(&indio_dev->mlock);
541
542 return ret ? ret : len;
543}
544
545static ssize_t iio_buffer_show_enable(struct device *dev,
546 struct device_attribute *attr,
547 char *buf)
548{
549 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
550 struct iio_buffer *buffer = indio_dev->buffer;
551
552 return sprintf(buf, "%d\n", iio_buffer_is_active(buffer));
553}
554
555static unsigned int iio_storage_bytes_for_si(struct iio_dev *indio_dev,
556 unsigned int scan_index)
557{
558 const struct iio_chan_spec *ch;
559 unsigned int bytes;
560
561 ch = iio_find_channel_from_si(indio_dev, scan_index);
562 bytes = ch->scan_type.storagebits / 8;
563 if (ch->scan_type.repeat > 1)
564 bytes *= ch->scan_type.repeat;
565 return bytes;
566}
567
568static unsigned int iio_storage_bytes_for_timestamp(struct iio_dev *indio_dev)
569{
570 return iio_storage_bytes_for_si(indio_dev,
571 indio_dev->scan_index_timestamp);
572}
573
574static int iio_compute_scan_bytes(struct iio_dev *indio_dev,
575 const unsigned long *mask, bool timestamp)
576{
577 unsigned bytes = 0;
578 int length, i, largest = 0;
579
580 /* How much space will the demuxed element take? */
581 for_each_set_bit(i, mask,
582 indio_dev->masklength) {
583 length = iio_storage_bytes_for_si(indio_dev, i);
584 bytes = ALIGN(bytes, length);
585 bytes += length;
586 largest = max(largest, length);
587 }
588
589 if (timestamp) {
590 length = iio_storage_bytes_for_timestamp(indio_dev);
591 bytes = ALIGN(bytes, length);
592 bytes += length;
593 largest = max(largest, length);
594 }
595
596 bytes = ALIGN(bytes, largest);
597 return bytes;
598}
599
600static void iio_buffer_activate(struct iio_dev *indio_dev,
601 struct iio_buffer *buffer)
602{
603 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
604
605 iio_buffer_get(buffer);
606 list_add(&buffer->buffer_list, &iio_dev_opaque->buffer_list);
607}
608
609static void iio_buffer_deactivate(struct iio_buffer *buffer)
610{
611 list_del_init(&buffer->buffer_list);
612 wake_up_interruptible(&buffer->pollq);
613 iio_buffer_put(buffer);
614}
615
616static void iio_buffer_deactivate_all(struct iio_dev *indio_dev)
617{
618 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
619 struct iio_buffer *buffer, *_buffer;
620
621 list_for_each_entry_safe(buffer, _buffer,
622 &iio_dev_opaque->buffer_list, buffer_list)
623 iio_buffer_deactivate(buffer);
624}
625
626static int iio_buffer_enable(struct iio_buffer *buffer,
627 struct iio_dev *indio_dev)
628{
629 if (!buffer->access->enable)
630 return 0;
631 return buffer->access->enable(buffer, indio_dev);
632}
633
634static int iio_buffer_disable(struct iio_buffer *buffer,
635 struct iio_dev *indio_dev)
636{
637 if (!buffer->access->disable)
638 return 0;
639 return buffer->access->disable(buffer, indio_dev);
640}
641
642static void iio_buffer_update_bytes_per_datum(struct iio_dev *indio_dev,
643 struct iio_buffer *buffer)
644{
645 unsigned int bytes;
646
647 if (!buffer->access->set_bytes_per_datum)
648 return;
649
650 bytes = iio_compute_scan_bytes(indio_dev, buffer->scan_mask,
651 buffer->scan_timestamp);
652
653 buffer->access->set_bytes_per_datum(buffer, bytes);
654}
655
656static int iio_buffer_request_update(struct iio_dev *indio_dev,
657 struct iio_buffer *buffer)
658{
659 int ret;
660
661 iio_buffer_update_bytes_per_datum(indio_dev, buffer);
662 if (buffer->access->request_update) {
663 ret = buffer->access->request_update(buffer);
664 if (ret) {
665 dev_dbg(&indio_dev->dev,
666 "Buffer not started: buffer parameter update failed (%d)\n",
667 ret);
668 return ret;
669 }
670 }
671
672 return 0;
673}
674
675static void iio_free_scan_mask(struct iio_dev *indio_dev,
676 const unsigned long *mask)
677{
678 /* If the mask is dynamically allocated free it, otherwise do nothing */
679 if (!indio_dev->available_scan_masks)
680 bitmap_free(mask);
681}
682
683struct iio_device_config {
684 unsigned int mode;
685 unsigned int watermark;
686 const unsigned long *scan_mask;
687 unsigned int scan_bytes;
688 bool scan_timestamp;
689};
690
691static int iio_verify_update(struct iio_dev *indio_dev,
692 struct iio_buffer *insert_buffer, struct iio_buffer *remove_buffer,
693 struct iio_device_config *config)
694{
695 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
696 unsigned long *compound_mask;
697 const unsigned long *scan_mask;
698 bool strict_scanmask = false;
699 struct iio_buffer *buffer;
700 bool scan_timestamp;
701 unsigned int modes;
702
703 if (insert_buffer &&
704 bitmap_empty(insert_buffer->scan_mask, indio_dev->masklength)) {
705 dev_dbg(&indio_dev->dev,
706 "At least one scan element must be enabled first\n");
707 return -EINVAL;
708 }
709
710 memset(config, 0, sizeof(*config));
711 config->watermark = ~0;
712
713 /*
714 * If there is just one buffer and we are removing it there is nothing
715 * to verify.
716 */
717 if (remove_buffer && !insert_buffer &&
718 list_is_singular(&iio_dev_opaque->buffer_list))
719 return 0;
720
721 modes = indio_dev->modes;
722
723 list_for_each_entry(buffer, &iio_dev_opaque->buffer_list, buffer_list) {
724 if (buffer == remove_buffer)
725 continue;
726 modes &= buffer->access->modes;
727 config->watermark = min(config->watermark, buffer->watermark);
728 }
729
730 if (insert_buffer) {
731 modes &= insert_buffer->access->modes;
732 config->watermark = min(config->watermark,
733 insert_buffer->watermark);
734 }
735
736 /* Definitely possible for devices to support both of these. */
737 if ((modes & INDIO_BUFFER_TRIGGERED) && indio_dev->trig) {
738 config->mode = INDIO_BUFFER_TRIGGERED;
739 } else if (modes & INDIO_BUFFER_HARDWARE) {
740 /*
741 * Keep things simple for now and only allow a single buffer to
742 * be connected in hardware mode.
743 */
744 if (insert_buffer && !list_empty(&iio_dev_opaque->buffer_list))
745 return -EINVAL;
746 config->mode = INDIO_BUFFER_HARDWARE;
747 strict_scanmask = true;
748 } else if (modes & INDIO_BUFFER_SOFTWARE) {
749 config->mode = INDIO_BUFFER_SOFTWARE;
750 } else {
751 /* Can only occur on first buffer */
752 if (indio_dev->modes & INDIO_BUFFER_TRIGGERED)
753 dev_dbg(&indio_dev->dev, "Buffer not started: no trigger\n");
754 return -EINVAL;
755 }
756
757 /* What scan mask do we actually have? */
758 compound_mask = bitmap_zalloc(indio_dev->masklength, GFP_KERNEL);
759 if (compound_mask == NULL)
760 return -ENOMEM;
761
762 scan_timestamp = false;
763
764 list_for_each_entry(buffer, &iio_dev_opaque->buffer_list, buffer_list) {
765 if (buffer == remove_buffer)
766 continue;
767 bitmap_or(compound_mask, compound_mask, buffer->scan_mask,
768 indio_dev->masklength);
769 scan_timestamp |= buffer->scan_timestamp;
770 }
771
772 if (insert_buffer) {
773 bitmap_or(compound_mask, compound_mask,
774 insert_buffer->scan_mask, indio_dev->masklength);
775 scan_timestamp |= insert_buffer->scan_timestamp;
776 }
777
778 if (indio_dev->available_scan_masks) {
779 scan_mask = iio_scan_mask_match(indio_dev->available_scan_masks,
780 indio_dev->masklength,
781 compound_mask,
782 strict_scanmask);
783 bitmap_free(compound_mask);
784 if (scan_mask == NULL)
785 return -EINVAL;
786 } else {
787 scan_mask = compound_mask;
788 }
789
790 config->scan_bytes = iio_compute_scan_bytes(indio_dev,
791 scan_mask, scan_timestamp);
792 config->scan_mask = scan_mask;
793 config->scan_timestamp = scan_timestamp;
794
795 return 0;
796}
797
798/**
799 * struct iio_demux_table - table describing demux memcpy ops
800 * @from: index to copy from
801 * @to: index to copy to
802 * @length: how many bytes to copy
803 * @l: list head used for management
804 */
805struct iio_demux_table {
806 unsigned from;
807 unsigned to;
808 unsigned length;
809 struct list_head l;
810};
811
812static void iio_buffer_demux_free(struct iio_buffer *buffer)
813{
814 struct iio_demux_table *p, *q;
815 list_for_each_entry_safe(p, q, &buffer->demux_list, l) {
816 list_del(&p->l);
817 kfree(p);
818 }
819}
820
821static int iio_buffer_add_demux(struct iio_buffer *buffer,
822 struct iio_demux_table **p, unsigned int in_loc, unsigned int out_loc,
823 unsigned int length)
824{
825
826 if (*p && (*p)->from + (*p)->length == in_loc &&
827 (*p)->to + (*p)->length == out_loc) {
828 (*p)->length += length;
829 } else {
830 *p = kmalloc(sizeof(**p), GFP_KERNEL);
831 if (*p == NULL)
832 return -ENOMEM;
833 (*p)->from = in_loc;
834 (*p)->to = out_loc;
835 (*p)->length = length;
836 list_add_tail(&(*p)->l, &buffer->demux_list);
837 }
838
839 return 0;
840}
841
842static int iio_buffer_update_demux(struct iio_dev *indio_dev,
843 struct iio_buffer *buffer)
844{
845 int ret, in_ind = -1, out_ind, length;
846 unsigned in_loc = 0, out_loc = 0;
847 struct iio_demux_table *p = NULL;
848
849 /* Clear out any old demux */
850 iio_buffer_demux_free(buffer);
851 kfree(buffer->demux_bounce);
852 buffer->demux_bounce = NULL;
853
854 /* First work out which scan mode we will actually have */
855 if (bitmap_equal(indio_dev->active_scan_mask,
856 buffer->scan_mask,
857 indio_dev->masklength))
858 return 0;
859
860 /* Now we have the two masks, work from least sig and build up sizes */
861 for_each_set_bit(out_ind,
862 buffer->scan_mask,
863 indio_dev->masklength) {
864 in_ind = find_next_bit(indio_dev->active_scan_mask,
865 indio_dev->masklength,
866 in_ind + 1);
867 while (in_ind != out_ind) {
868 in_ind = find_next_bit(indio_dev->active_scan_mask,
869 indio_dev->masklength,
870 in_ind + 1);
871 length = iio_storage_bytes_for_si(indio_dev, in_ind);
872 /* Make sure we are aligned */
873 in_loc = roundup(in_loc, length) + length;
874 }
875 length = iio_storage_bytes_for_si(indio_dev, in_ind);
876 out_loc = roundup(out_loc, length);
877 in_loc = roundup(in_loc, length);
878 ret = iio_buffer_add_demux(buffer, &p, in_loc, out_loc, length);
879 if (ret)
880 goto error_clear_mux_table;
881 out_loc += length;
882 in_loc += length;
883 }
884 /* Relies on scan_timestamp being last */
885 if (buffer->scan_timestamp) {
886 length = iio_storage_bytes_for_timestamp(indio_dev);
887 out_loc = roundup(out_loc, length);
888 in_loc = roundup(in_loc, length);
889 ret = iio_buffer_add_demux(buffer, &p, in_loc, out_loc, length);
890 if (ret)
891 goto error_clear_mux_table;
892 out_loc += length;
893 in_loc += length;
894 }
895 buffer->demux_bounce = kzalloc(out_loc, GFP_KERNEL);
896 if (buffer->demux_bounce == NULL) {
897 ret = -ENOMEM;
898 goto error_clear_mux_table;
899 }
900 return 0;
901
902error_clear_mux_table:
903 iio_buffer_demux_free(buffer);
904
905 return ret;
906}
907
908static int iio_update_demux(struct iio_dev *indio_dev)
909{
910 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
911 struct iio_buffer *buffer;
912 int ret;
913
914 list_for_each_entry(buffer, &iio_dev_opaque->buffer_list, buffer_list) {
915 ret = iio_buffer_update_demux(indio_dev, buffer);
916 if (ret < 0)
917 goto error_clear_mux_table;
918 }
919 return 0;
920
921error_clear_mux_table:
922 list_for_each_entry(buffer, &iio_dev_opaque->buffer_list, buffer_list)
923 iio_buffer_demux_free(buffer);
924
925 return ret;
926}
927
928static int iio_enable_buffers(struct iio_dev *indio_dev,
929 struct iio_device_config *config)
930{
931 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
932 struct iio_buffer *buffer;
933 int ret;
934
935 indio_dev->active_scan_mask = config->scan_mask;
936 indio_dev->scan_timestamp = config->scan_timestamp;
937 indio_dev->scan_bytes = config->scan_bytes;
938 indio_dev->currentmode = config->mode;
939
940 iio_update_demux(indio_dev);
941
942 /* Wind up again */
943 if (indio_dev->setup_ops->preenable) {
944 ret = indio_dev->setup_ops->preenable(indio_dev);
945 if (ret) {
946 dev_dbg(&indio_dev->dev,
947 "Buffer not started: buffer preenable failed (%d)\n", ret);
948 goto err_undo_config;
949 }
950 }
951
952 if (indio_dev->info->update_scan_mode) {
953 ret = indio_dev->info
954 ->update_scan_mode(indio_dev,
955 indio_dev->active_scan_mask);
956 if (ret < 0) {
957 dev_dbg(&indio_dev->dev,
958 "Buffer not started: update scan mode failed (%d)\n",
959 ret);
960 goto err_run_postdisable;
961 }
962 }
963
964 if (indio_dev->info->hwfifo_set_watermark)
965 indio_dev->info->hwfifo_set_watermark(indio_dev,
966 config->watermark);
967
968 list_for_each_entry(buffer, &iio_dev_opaque->buffer_list, buffer_list) {
969 ret = iio_buffer_enable(buffer, indio_dev);
970 if (ret)
971 goto err_disable_buffers;
972 }
973
974 if (indio_dev->currentmode == INDIO_BUFFER_TRIGGERED) {
975 ret = iio_trigger_attach_poll_func(indio_dev->trig,
976 indio_dev->pollfunc);
977 if (ret)
978 goto err_disable_buffers;
979 }
980
981 if (indio_dev->setup_ops->postenable) {
982 ret = indio_dev->setup_ops->postenable(indio_dev);
983 if (ret) {
984 dev_dbg(&indio_dev->dev,
985 "Buffer not started: postenable failed (%d)\n", ret);
986 goto err_detach_pollfunc;
987 }
988 }
989
990 return 0;
991
992err_detach_pollfunc:
993 if (indio_dev->currentmode == INDIO_BUFFER_TRIGGERED) {
994 iio_trigger_detach_poll_func(indio_dev->trig,
995 indio_dev->pollfunc);
996 }
997err_disable_buffers:
998 list_for_each_entry_continue_reverse(buffer, &iio_dev_opaque->buffer_list,
999 buffer_list)
1000 iio_buffer_disable(buffer, indio_dev);
1001err_run_postdisable:
1002 if (indio_dev->setup_ops->postdisable)
1003 indio_dev->setup_ops->postdisable(indio_dev);
1004err_undo_config:
1005 indio_dev->currentmode = INDIO_DIRECT_MODE;
1006 indio_dev->active_scan_mask = NULL;
1007
1008 return ret;
1009}
1010
1011static int iio_disable_buffers(struct iio_dev *indio_dev)
1012{
1013 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
1014 struct iio_buffer *buffer;
1015 int ret = 0;
1016 int ret2;
1017
1018 /* Wind down existing buffers - iff there are any */
1019 if (list_empty(&iio_dev_opaque->buffer_list))
1020 return 0;
1021
1022 /*
1023 * If things go wrong at some step in disable we still need to continue
1024 * to perform the other steps, otherwise we leave the device in a
1025 * inconsistent state. We return the error code for the first error we
1026 * encountered.
1027 */
1028
1029 if (indio_dev->setup_ops->predisable) {
1030 ret2 = indio_dev->setup_ops->predisable(indio_dev);
1031 if (ret2 && !ret)
1032 ret = ret2;
1033 }
1034
1035 if (indio_dev->currentmode == INDIO_BUFFER_TRIGGERED) {
1036 iio_trigger_detach_poll_func(indio_dev->trig,
1037 indio_dev->pollfunc);
1038 }
1039
1040 list_for_each_entry(buffer, &iio_dev_opaque->buffer_list, buffer_list) {
1041 ret2 = iio_buffer_disable(buffer, indio_dev);
1042 if (ret2 && !ret)
1043 ret = ret2;
1044 }
1045
1046 if (indio_dev->setup_ops->postdisable) {
1047 ret2 = indio_dev->setup_ops->postdisable(indio_dev);
1048 if (ret2 && !ret)
1049 ret = ret2;
1050 }
1051
1052 iio_free_scan_mask(indio_dev, indio_dev->active_scan_mask);
1053 indio_dev->active_scan_mask = NULL;
1054 indio_dev->currentmode = INDIO_DIRECT_MODE;
1055
1056 return ret;
1057}
1058
1059static int __iio_update_buffers(struct iio_dev *indio_dev,
1060 struct iio_buffer *insert_buffer,
1061 struct iio_buffer *remove_buffer)
1062{
1063 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
1064 struct iio_device_config new_config;
1065 int ret;
1066
1067 ret = iio_verify_update(indio_dev, insert_buffer, remove_buffer,
1068 &new_config);
1069 if (ret)
1070 return ret;
1071
1072 if (insert_buffer) {
1073 ret = iio_buffer_request_update(indio_dev, insert_buffer);
1074 if (ret)
1075 goto err_free_config;
1076 }
1077
1078 ret = iio_disable_buffers(indio_dev);
1079 if (ret)
1080 goto err_deactivate_all;
1081
1082 if (remove_buffer)
1083 iio_buffer_deactivate(remove_buffer);
1084 if (insert_buffer)
1085 iio_buffer_activate(indio_dev, insert_buffer);
1086
1087 /* If no buffers in list, we are done */
1088 if (list_empty(&iio_dev_opaque->buffer_list))
1089 return 0;
1090
1091 ret = iio_enable_buffers(indio_dev, &new_config);
1092 if (ret)
1093 goto err_deactivate_all;
1094
1095 return 0;
1096
1097err_deactivate_all:
1098 /*
1099 * We've already verified that the config is valid earlier. If things go
1100 * wrong in either enable or disable the most likely reason is an IO
1101 * error from the device. In this case there is no good recovery
1102 * strategy. Just make sure to disable everything and leave the device
1103 * in a sane state. With a bit of luck the device might come back to
1104 * life again later and userspace can try again.
1105 */
1106 iio_buffer_deactivate_all(indio_dev);
1107
1108err_free_config:
1109 iio_free_scan_mask(indio_dev, new_config.scan_mask);
1110 return ret;
1111}
1112
1113int iio_update_buffers(struct iio_dev *indio_dev,
1114 struct iio_buffer *insert_buffer,
1115 struct iio_buffer *remove_buffer)
1116{
1117 int ret;
1118
1119 if (insert_buffer == remove_buffer)
1120 return 0;
1121
1122 mutex_lock(&indio_dev->info_exist_lock);
1123 mutex_lock(&indio_dev->mlock);
1124
1125 if (insert_buffer && iio_buffer_is_active(insert_buffer))
1126 insert_buffer = NULL;
1127
1128 if (remove_buffer && !iio_buffer_is_active(remove_buffer))
1129 remove_buffer = NULL;
1130
1131 if (!insert_buffer && !remove_buffer) {
1132 ret = 0;
1133 goto out_unlock;
1134 }
1135
1136 if (indio_dev->info == NULL) {
1137 ret = -ENODEV;
1138 goto out_unlock;
1139 }
1140
1141 ret = __iio_update_buffers(indio_dev, insert_buffer, remove_buffer);
1142
1143out_unlock:
1144 mutex_unlock(&indio_dev->mlock);
1145 mutex_unlock(&indio_dev->info_exist_lock);
1146
1147 return ret;
1148}
1149EXPORT_SYMBOL_GPL(iio_update_buffers);
1150
1151void iio_disable_all_buffers(struct iio_dev *indio_dev)
1152{
1153 iio_disable_buffers(indio_dev);
1154 iio_buffer_deactivate_all(indio_dev);
1155}
1156
1157static ssize_t iio_buffer_store_enable(struct device *dev,
1158 struct device_attribute *attr,
1159 const char *buf,
1160 size_t len)
1161{
1162 int ret;
1163 bool requested_state;
1164 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
1165 struct iio_buffer *buffer = indio_dev->buffer;
1166 bool inlist;
1167
1168 ret = strtobool(buf, &requested_state);
1169 if (ret < 0)
1170 return ret;
1171
1172 mutex_lock(&indio_dev->mlock);
1173
1174 /* Find out if it is in the list */
1175 inlist = iio_buffer_is_active(buffer);
1176 /* Already in desired state */
1177 if (inlist == requested_state)
1178 goto done;
1179
1180 if (requested_state)
1181 ret = __iio_update_buffers(indio_dev, buffer, NULL);
1182 else
1183 ret = __iio_update_buffers(indio_dev, NULL, buffer);
1184
1185done:
1186 mutex_unlock(&indio_dev->mlock);
1187 return (ret < 0) ? ret : len;
1188}
1189
1190static const char * const iio_scan_elements_group_name = "scan_elements";
1191
1192static ssize_t iio_buffer_show_watermark(struct device *dev,
1193 struct device_attribute *attr,
1194 char *buf)
1195{
1196 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
1197 struct iio_buffer *buffer = indio_dev->buffer;
1198
1199 return sprintf(buf, "%u\n", buffer->watermark);
1200}
1201
1202static ssize_t iio_buffer_store_watermark(struct device *dev,
1203 struct device_attribute *attr,
1204 const char *buf,
1205 size_t len)
1206{
1207 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
1208 struct iio_buffer *buffer = indio_dev->buffer;
1209 unsigned int val;
1210 int ret;
1211
1212 ret = kstrtouint(buf, 10, &val);
1213 if (ret)
1214 return ret;
1215 if (!val)
1216 return -EINVAL;
1217
1218 mutex_lock(&indio_dev->mlock);
1219
1220 if (val > buffer->length) {
1221 ret = -EINVAL;
1222 goto out;
1223 }
1224
1225 if (iio_buffer_is_active(buffer)) {
1226 ret = -EBUSY;
1227 goto out;
1228 }
1229
1230 buffer->watermark = val;
1231out:
1232 mutex_unlock(&indio_dev->mlock);
1233
1234 return ret ? ret : len;
1235}
1236
1237static ssize_t iio_dma_show_data_available(struct device *dev,
1238 struct device_attribute *attr,
1239 char *buf)
1240{
1241 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
1242 struct iio_buffer *buffer = indio_dev->buffer;
1243
1244 return sprintf(buf, "%zu\n", iio_buffer_data_available(buffer));
1245}
1246
1247static DEVICE_ATTR(length, S_IRUGO | S_IWUSR, iio_buffer_read_length,
1248 iio_buffer_write_length);
1249static struct device_attribute dev_attr_length_ro = __ATTR(length,
1250 S_IRUGO, iio_buffer_read_length, NULL);
1251static DEVICE_ATTR(enable, S_IRUGO | S_IWUSR,
1252 iio_buffer_show_enable, iio_buffer_store_enable);
1253static DEVICE_ATTR(watermark, S_IRUGO | S_IWUSR,
1254 iio_buffer_show_watermark, iio_buffer_store_watermark);
1255static struct device_attribute dev_attr_watermark_ro = __ATTR(watermark,
1256 S_IRUGO, iio_buffer_show_watermark, NULL);
1257static DEVICE_ATTR(data_available, S_IRUGO,
1258 iio_dma_show_data_available, NULL);
1259
1260static struct attribute *iio_buffer_attrs[] = {
1261 &dev_attr_length.attr,
1262 &dev_attr_enable.attr,
1263 &dev_attr_watermark.attr,
1264 &dev_attr_data_available.attr,
1265};
1266
1267int iio_buffer_alloc_sysfs_and_mask(struct iio_dev *indio_dev)
1268{
1269 struct iio_dev_attr *p;
1270 struct attribute **attr;
1271 struct iio_buffer *buffer = indio_dev->buffer;
1272 int ret, i, attrn, attrcount;
1273 const struct iio_chan_spec *channels;
1274
1275 channels = indio_dev->channels;
1276 if (channels) {
1277 int ml = indio_dev->masklength;
1278
1279 for (i = 0; i < indio_dev->num_channels; i++)
1280 ml = max(ml, channels[i].scan_index + 1);
1281 indio_dev->masklength = ml;
1282 }
1283
1284 if (!buffer)
1285 return 0;
1286
1287 attrcount = 0;
1288 if (buffer->attrs) {
1289 while (buffer->attrs[attrcount] != NULL)
1290 attrcount++;
1291 }
1292
1293 attr = kcalloc(attrcount + ARRAY_SIZE(iio_buffer_attrs) + 1,
1294 sizeof(struct attribute *), GFP_KERNEL);
1295 if (!attr)
1296 return -ENOMEM;
1297
1298 memcpy(attr, iio_buffer_attrs, sizeof(iio_buffer_attrs));
1299 if (!buffer->access->set_length)
1300 attr[0] = &dev_attr_length_ro.attr;
1301
1302 if (buffer->access->flags & INDIO_BUFFER_FLAG_FIXED_WATERMARK)
1303 attr[2] = &dev_attr_watermark_ro.attr;
1304
1305 if (buffer->attrs)
1306 memcpy(&attr[ARRAY_SIZE(iio_buffer_attrs)], buffer->attrs,
1307 sizeof(struct attribute *) * attrcount);
1308
1309 attr[attrcount + ARRAY_SIZE(iio_buffer_attrs)] = NULL;
1310
1311 buffer->buffer_group.name = "buffer";
1312 buffer->buffer_group.attrs = attr;
1313
1314 indio_dev->groups[indio_dev->groupcounter++] = &buffer->buffer_group;
1315
1316 attrcount = 0;
1317 INIT_LIST_HEAD(&buffer->scan_el_dev_attr_list);
1318 channels = indio_dev->channels;
1319 if (channels) {
1320 /* new magic */
1321 for (i = 0; i < indio_dev->num_channels; i++) {
1322 if (channels[i].scan_index < 0)
1323 continue;
1324
1325 ret = iio_buffer_add_channel_sysfs(indio_dev, buffer,
1326 &channels[i]);
1327 if (ret < 0)
1328 goto error_cleanup_dynamic;
1329 attrcount += ret;
1330 if (channels[i].type == IIO_TIMESTAMP)
1331 indio_dev->scan_index_timestamp =
1332 channels[i].scan_index;
1333 }
1334 if (indio_dev->masklength && buffer->scan_mask == NULL) {
1335 buffer->scan_mask = bitmap_zalloc(indio_dev->masklength,
1336 GFP_KERNEL);
1337 if (buffer->scan_mask == NULL) {
1338 ret = -ENOMEM;
1339 goto error_cleanup_dynamic;
1340 }
1341 }
1342 }
1343
1344 buffer->scan_el_group.name = iio_scan_elements_group_name;
1345
1346 buffer->scan_el_group.attrs = kcalloc(attrcount + 1,
1347 sizeof(buffer->scan_el_group.attrs[0]),
1348 GFP_KERNEL);
1349 if (buffer->scan_el_group.attrs == NULL) {
1350 ret = -ENOMEM;
1351 goto error_free_scan_mask;
1352 }
1353 attrn = 0;
1354
1355 list_for_each_entry(p, &buffer->scan_el_dev_attr_list, l)
1356 buffer->scan_el_group.attrs[attrn++] = &p->dev_attr.attr;
1357 indio_dev->groups[indio_dev->groupcounter++] = &buffer->scan_el_group;
1358
1359 return 0;
1360
1361error_free_scan_mask:
1362 bitmap_free(buffer->scan_mask);
1363error_cleanup_dynamic:
1364 iio_free_chan_devattr_list(&buffer->scan_el_dev_attr_list);
1365 kfree(buffer->buffer_group.attrs);
1366
1367 return ret;
1368}
1369
1370void iio_buffer_free_sysfs_and_mask(struct iio_dev *indio_dev)
1371{
1372 struct iio_buffer *buffer = indio_dev->buffer;
1373
1374 if (!buffer)
1375 return;
1376
1377 bitmap_free(buffer->scan_mask);
1378 kfree(buffer->buffer_group.attrs);
1379 kfree(buffer->scan_el_group.attrs);
1380 iio_free_chan_devattr_list(&buffer->scan_el_dev_attr_list);
1381}
1382
1383/**
1384 * iio_validate_scan_mask_onehot() - Validates that exactly one channel is selected
1385 * @indio_dev: the iio device
1386 * @mask: scan mask to be checked
1387 *
1388 * Return true if exactly one bit is set in the scan mask, false otherwise. It
1389 * can be used for devices where only one channel can be active for sampling at
1390 * a time.
1391 */
1392bool iio_validate_scan_mask_onehot(struct iio_dev *indio_dev,
1393 const unsigned long *mask)
1394{
1395 return bitmap_weight(mask, indio_dev->masklength) == 1;
1396}
1397EXPORT_SYMBOL_GPL(iio_validate_scan_mask_onehot);
1398
1399static const void *iio_demux(struct iio_buffer *buffer,
1400 const void *datain)
1401{
1402 struct iio_demux_table *t;
1403
1404 if (list_empty(&buffer->demux_list))
1405 return datain;
1406 list_for_each_entry(t, &buffer->demux_list, l)
1407 memcpy(buffer->demux_bounce + t->to,
1408 datain + t->from, t->length);
1409
1410 return buffer->demux_bounce;
1411}
1412
1413static int iio_push_to_buffer(struct iio_buffer *buffer, const void *data)
1414{
1415 const void *dataout = iio_demux(buffer, data);
1416 int ret;
1417
1418 ret = buffer->access->store_to(buffer, dataout);
1419 if (ret)
1420 return ret;
1421
1422 /*
1423 * We can't just test for watermark to decide if we wake the poll queue
1424 * because read may request less samples than the watermark.
1425 */
1426 wake_up_interruptible_poll(&buffer->pollq, EPOLLIN | EPOLLRDNORM);
1427 return 0;
1428}
1429
1430/**
1431 * iio_push_to_buffers() - push to a registered buffer.
1432 * @indio_dev: iio_dev structure for device.
1433 * @data: Full scan.
1434 */
1435int iio_push_to_buffers(struct iio_dev *indio_dev, const void *data)
1436{
1437 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
1438 int ret;
1439 struct iio_buffer *buf;
1440
1441 list_for_each_entry(buf, &iio_dev_opaque->buffer_list, buffer_list) {
1442 ret = iio_push_to_buffer(buf, data);
1443 if (ret < 0)
1444 return ret;
1445 }
1446
1447 return 0;
1448}
1449EXPORT_SYMBOL_GPL(iio_push_to_buffers);
1450
1451/**
1452 * iio_buffer_release() - Free a buffer's resources
1453 * @ref: Pointer to the kref embedded in the iio_buffer struct
1454 *
1455 * This function is called when the last reference to the buffer has been
1456 * dropped. It will typically free all resources allocated by the buffer. Do not
1457 * call this function manually, always use iio_buffer_put() when done using a
1458 * buffer.
1459 */
1460static void iio_buffer_release(struct kref *ref)
1461{
1462 struct iio_buffer *buffer = container_of(ref, struct iio_buffer, ref);
1463
1464 buffer->access->release(buffer);
1465}
1466
1467/**
1468 * iio_buffer_get() - Grab a reference to the buffer
1469 * @buffer: The buffer to grab a reference for, may be NULL
1470 *
1471 * Returns the pointer to the buffer that was passed into the function.
1472 */
1473struct iio_buffer *iio_buffer_get(struct iio_buffer *buffer)
1474{
1475 if (buffer)
1476 kref_get(&buffer->ref);
1477
1478 return buffer;
1479}
1480EXPORT_SYMBOL_GPL(iio_buffer_get);
1481
1482/**
1483 * iio_buffer_put() - Release the reference to the buffer
1484 * @buffer: The buffer to release the reference for, may be NULL
1485 */
1486void iio_buffer_put(struct iio_buffer *buffer)
1487{
1488 if (buffer)
1489 kref_put(&buffer->ref, iio_buffer_release);
1490}
1491EXPORT_SYMBOL_GPL(iio_buffer_put);
1492
1493/**
1494 * iio_device_attach_buffer - Attach a buffer to a IIO device
1495 * @indio_dev: The device the buffer should be attached to
1496 * @buffer: The buffer to attach to the device
1497 *
1498 * This function attaches a buffer to a IIO device. The buffer stays attached to
1499 * the device until the device is freed. The function should only be called at
1500 * most once per device.
1501 */
1502void iio_device_attach_buffer(struct iio_dev *indio_dev,
1503 struct iio_buffer *buffer)
1504{
1505 indio_dev->buffer = iio_buffer_get(buffer);
1506}
1507EXPORT_SYMBOL_GPL(iio_device_attach_buffer);
1// SPDX-License-Identifier: GPL-2.0-only
2/* The industrial I/O core
3 *
4 * Copyright (c) 2008 Jonathan Cameron
5 *
6 * Handling of buffer allocation / resizing.
7 *
8 * Things to look at here.
9 * - Better memory allocation techniques?
10 * - Alternative access techniques?
11 */
12#include <linux/anon_inodes.h>
13#include <linux/kernel.h>
14#include <linux/export.h>
15#include <linux/device.h>
16#include <linux/file.h>
17#include <linux/fs.h>
18#include <linux/cdev.h>
19#include <linux/slab.h>
20#include <linux/poll.h>
21#include <linux/sched/signal.h>
22
23#include <linux/iio/iio.h>
24#include <linux/iio/iio-opaque.h>
25#include "iio_core.h"
26#include "iio_core_trigger.h"
27#include <linux/iio/sysfs.h>
28#include <linux/iio/buffer.h>
29#include <linux/iio/buffer_impl.h>
30
31static const char * const iio_endian_prefix[] = {
32 [IIO_BE] = "be",
33 [IIO_LE] = "le",
34};
35
36static bool iio_buffer_is_active(struct iio_buffer *buf)
37{
38 return !list_empty(&buf->buffer_list);
39}
40
41static size_t iio_buffer_data_available(struct iio_buffer *buf)
42{
43 return buf->access->data_available(buf);
44}
45
46static int iio_buffer_flush_hwfifo(struct iio_dev *indio_dev,
47 struct iio_buffer *buf, size_t required)
48{
49 if (!indio_dev->info->hwfifo_flush_to_buffer)
50 return -ENODEV;
51
52 return indio_dev->info->hwfifo_flush_to_buffer(indio_dev, required);
53}
54
55static bool iio_buffer_ready(struct iio_dev *indio_dev, struct iio_buffer *buf,
56 size_t to_wait, int to_flush)
57{
58 size_t avail;
59 int flushed = 0;
60
61 /* wakeup if the device was unregistered */
62 if (!indio_dev->info)
63 return true;
64
65 /* drain the buffer if it was disabled */
66 if (!iio_buffer_is_active(buf)) {
67 to_wait = min_t(size_t, to_wait, 1);
68 to_flush = 0;
69 }
70
71 avail = iio_buffer_data_available(buf);
72
73 if (avail >= to_wait) {
74 /* force a flush for non-blocking reads */
75 if (!to_wait && avail < to_flush)
76 iio_buffer_flush_hwfifo(indio_dev, buf,
77 to_flush - avail);
78 return true;
79 }
80
81 if (to_flush)
82 flushed = iio_buffer_flush_hwfifo(indio_dev, buf,
83 to_wait - avail);
84 if (flushed <= 0)
85 return false;
86
87 if (avail + flushed >= to_wait)
88 return true;
89
90 return false;
91}
92
93/**
94 * iio_buffer_read() - chrdev read for buffer access
95 * @filp: File structure pointer for the char device
96 * @buf: Destination buffer for iio buffer read
97 * @n: First n bytes to read
98 * @f_ps: Long offset provided by the user as a seek position
99 *
100 * This function relies on all buffer implementations having an
101 * iio_buffer as their first element.
102 *
103 * Return: negative values corresponding to error codes or ret != 0
104 * for ending the reading activity
105 **/
106static ssize_t iio_buffer_read(struct file *filp, char __user *buf,
107 size_t n, loff_t *f_ps)
108{
109 struct iio_dev_buffer_pair *ib = filp->private_data;
110 struct iio_buffer *rb = ib->buffer;
111 struct iio_dev *indio_dev = ib->indio_dev;
112 DEFINE_WAIT_FUNC(wait, woken_wake_function);
113 size_t datum_size;
114 size_t to_wait;
115 int ret = 0;
116
117 if (!indio_dev->info)
118 return -ENODEV;
119
120 if (!rb || !rb->access->read)
121 return -EINVAL;
122
123 if (rb->direction != IIO_BUFFER_DIRECTION_IN)
124 return -EPERM;
125
126 datum_size = rb->bytes_per_datum;
127
128 /*
129 * If datum_size is 0 there will never be anything to read from the
130 * buffer, so signal end of file now.
131 */
132 if (!datum_size)
133 return 0;
134
135 if (filp->f_flags & O_NONBLOCK)
136 to_wait = 0;
137 else
138 to_wait = min_t(size_t, n / datum_size, rb->watermark);
139
140 add_wait_queue(&rb->pollq, &wait);
141 do {
142 if (!indio_dev->info) {
143 ret = -ENODEV;
144 break;
145 }
146
147 if (!iio_buffer_ready(indio_dev, rb, to_wait, n / datum_size)) {
148 if (signal_pending(current)) {
149 ret = -ERESTARTSYS;
150 break;
151 }
152
153 wait_woken(&wait, TASK_INTERRUPTIBLE,
154 MAX_SCHEDULE_TIMEOUT);
155 continue;
156 }
157
158 ret = rb->access->read(rb, n, buf);
159 if (ret == 0 && (filp->f_flags & O_NONBLOCK))
160 ret = -EAGAIN;
161 } while (ret == 0);
162 remove_wait_queue(&rb->pollq, &wait);
163
164 return ret;
165}
166
167static size_t iio_buffer_space_available(struct iio_buffer *buf)
168{
169 if (buf->access->space_available)
170 return buf->access->space_available(buf);
171
172 return SIZE_MAX;
173}
174
175static ssize_t iio_buffer_write(struct file *filp, const char __user *buf,
176 size_t n, loff_t *f_ps)
177{
178 struct iio_dev_buffer_pair *ib = filp->private_data;
179 struct iio_buffer *rb = ib->buffer;
180 struct iio_dev *indio_dev = ib->indio_dev;
181 DEFINE_WAIT_FUNC(wait, woken_wake_function);
182 int ret = 0;
183 size_t written;
184
185 if (!indio_dev->info)
186 return -ENODEV;
187
188 if (!rb || !rb->access->write)
189 return -EINVAL;
190
191 if (rb->direction != IIO_BUFFER_DIRECTION_OUT)
192 return -EPERM;
193
194 written = 0;
195 add_wait_queue(&rb->pollq, &wait);
196 do {
197 if (!indio_dev->info)
198 return -ENODEV;
199
200 if (!iio_buffer_space_available(rb)) {
201 if (signal_pending(current)) {
202 ret = -ERESTARTSYS;
203 break;
204 }
205
206 if (filp->f_flags & O_NONBLOCK) {
207 if (!written)
208 ret = -EAGAIN;
209 break;
210 }
211
212 wait_woken(&wait, TASK_INTERRUPTIBLE,
213 MAX_SCHEDULE_TIMEOUT);
214 continue;
215 }
216
217 ret = rb->access->write(rb, n - written, buf + written);
218 if (ret < 0)
219 break;
220
221 written += ret;
222
223 } while (written != n);
224 remove_wait_queue(&rb->pollq, &wait);
225
226 return ret < 0 ? ret : written;
227}
228
229/**
230 * iio_buffer_poll() - poll the buffer to find out if it has data
231 * @filp: File structure pointer for device access
232 * @wait: Poll table structure pointer for which the driver adds
233 * a wait queue
234 *
235 * Return: (EPOLLIN | EPOLLRDNORM) if data is available for reading
236 * or 0 for other cases
237 */
238static __poll_t iio_buffer_poll(struct file *filp,
239 struct poll_table_struct *wait)
240{
241 struct iio_dev_buffer_pair *ib = filp->private_data;
242 struct iio_buffer *rb = ib->buffer;
243 struct iio_dev *indio_dev = ib->indio_dev;
244
245 if (!indio_dev->info || !rb)
246 return 0;
247
248 poll_wait(filp, &rb->pollq, wait);
249
250 switch (rb->direction) {
251 case IIO_BUFFER_DIRECTION_IN:
252 if (iio_buffer_ready(indio_dev, rb, rb->watermark, 0))
253 return EPOLLIN | EPOLLRDNORM;
254 break;
255 case IIO_BUFFER_DIRECTION_OUT:
256 if (iio_buffer_space_available(rb))
257 return EPOLLOUT | EPOLLWRNORM;
258 break;
259 }
260
261 return 0;
262}
263
264ssize_t iio_buffer_read_wrapper(struct file *filp, char __user *buf,
265 size_t n, loff_t *f_ps)
266{
267 struct iio_dev_buffer_pair *ib = filp->private_data;
268 struct iio_buffer *rb = ib->buffer;
269
270 /* check if buffer was opened through new API */
271 if (test_bit(IIO_BUSY_BIT_POS, &rb->flags))
272 return -EBUSY;
273
274 return iio_buffer_read(filp, buf, n, f_ps);
275}
276
277ssize_t iio_buffer_write_wrapper(struct file *filp, const char __user *buf,
278 size_t n, loff_t *f_ps)
279{
280 struct iio_dev_buffer_pair *ib = filp->private_data;
281 struct iio_buffer *rb = ib->buffer;
282
283 /* check if buffer was opened through new API */
284 if (test_bit(IIO_BUSY_BIT_POS, &rb->flags))
285 return -EBUSY;
286
287 return iio_buffer_write(filp, buf, n, f_ps);
288}
289
290__poll_t iio_buffer_poll_wrapper(struct file *filp,
291 struct poll_table_struct *wait)
292{
293 struct iio_dev_buffer_pair *ib = filp->private_data;
294 struct iio_buffer *rb = ib->buffer;
295
296 /* check if buffer was opened through new API */
297 if (test_bit(IIO_BUSY_BIT_POS, &rb->flags))
298 return 0;
299
300 return iio_buffer_poll(filp, wait);
301}
302
303/**
304 * iio_buffer_wakeup_poll - Wakes up the buffer waitqueue
305 * @indio_dev: The IIO device
306 *
307 * Wakes up the event waitqueue used for poll(). Should usually
308 * be called when the device is unregistered.
309 */
310void iio_buffer_wakeup_poll(struct iio_dev *indio_dev)
311{
312 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
313 struct iio_buffer *buffer;
314 unsigned int i;
315
316 for (i = 0; i < iio_dev_opaque->attached_buffers_cnt; i++) {
317 buffer = iio_dev_opaque->attached_buffers[i];
318 wake_up(&buffer->pollq);
319 }
320}
321
322int iio_pop_from_buffer(struct iio_buffer *buffer, void *data)
323{
324 if (!buffer || !buffer->access || !buffer->access->remove_from)
325 return -EINVAL;
326
327 return buffer->access->remove_from(buffer, data);
328}
329EXPORT_SYMBOL_GPL(iio_pop_from_buffer);
330
331void iio_buffer_init(struct iio_buffer *buffer)
332{
333 INIT_LIST_HEAD(&buffer->demux_list);
334 INIT_LIST_HEAD(&buffer->buffer_list);
335 init_waitqueue_head(&buffer->pollq);
336 kref_init(&buffer->ref);
337 if (!buffer->watermark)
338 buffer->watermark = 1;
339}
340EXPORT_SYMBOL(iio_buffer_init);
341
342void iio_device_detach_buffers(struct iio_dev *indio_dev)
343{
344 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
345 struct iio_buffer *buffer;
346 unsigned int i;
347
348 for (i = 0; i < iio_dev_opaque->attached_buffers_cnt; i++) {
349 buffer = iio_dev_opaque->attached_buffers[i];
350 iio_buffer_put(buffer);
351 }
352
353 kfree(iio_dev_opaque->attached_buffers);
354}
355
356static ssize_t iio_show_scan_index(struct device *dev,
357 struct device_attribute *attr,
358 char *buf)
359{
360 return sysfs_emit(buf, "%u\n", to_iio_dev_attr(attr)->c->scan_index);
361}
362
363static ssize_t iio_show_fixed_type(struct device *dev,
364 struct device_attribute *attr,
365 char *buf)
366{
367 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
368 u8 type = this_attr->c->scan_type.endianness;
369
370 if (type == IIO_CPU) {
371#ifdef __LITTLE_ENDIAN
372 type = IIO_LE;
373#else
374 type = IIO_BE;
375#endif
376 }
377 if (this_attr->c->scan_type.repeat > 1)
378 return sysfs_emit(buf, "%s:%c%d/%dX%d>>%u\n",
379 iio_endian_prefix[type],
380 this_attr->c->scan_type.sign,
381 this_attr->c->scan_type.realbits,
382 this_attr->c->scan_type.storagebits,
383 this_attr->c->scan_type.repeat,
384 this_attr->c->scan_type.shift);
385 else
386 return sysfs_emit(buf, "%s:%c%d/%d>>%u\n",
387 iio_endian_prefix[type],
388 this_attr->c->scan_type.sign,
389 this_attr->c->scan_type.realbits,
390 this_attr->c->scan_type.storagebits,
391 this_attr->c->scan_type.shift);
392}
393
394static ssize_t iio_scan_el_show(struct device *dev,
395 struct device_attribute *attr,
396 char *buf)
397{
398 int ret;
399 struct iio_buffer *buffer = to_iio_dev_attr(attr)->buffer;
400
401 /* Ensure ret is 0 or 1. */
402 ret = !!test_bit(to_iio_dev_attr(attr)->address,
403 buffer->scan_mask);
404
405 return sysfs_emit(buf, "%d\n", ret);
406}
407
408/* Note NULL used as error indicator as it doesn't make sense. */
409static const unsigned long *iio_scan_mask_match(const unsigned long *av_masks,
410 unsigned int masklength,
411 const unsigned long *mask,
412 bool strict)
413{
414 if (bitmap_empty(mask, masklength))
415 return NULL;
416 /*
417 * The condition here do not handle multi-long masks correctly.
418 * It only checks the first long to be zero, and will use such mask
419 * as a terminator even if there was bits set after the first long.
420 *
421 * Correct check would require using:
422 * while (!bitmap_empty(av_masks, masklength))
423 * instead. This is potentially hazardous because the
424 * avaliable_scan_masks is a zero terminated array of longs - and
425 * using the proper bitmap_empty() check for multi-long wide masks
426 * would require the array to be terminated with multiple zero longs -
427 * which is not such an usual pattern.
428 *
429 * As writing of this no multi-long wide masks were found in-tree, so
430 * the simple while (*av_masks) check is working.
431 */
432 while (*av_masks) {
433 if (strict) {
434 if (bitmap_equal(mask, av_masks, masklength))
435 return av_masks;
436 } else {
437 if (bitmap_subset(mask, av_masks, masklength))
438 return av_masks;
439 }
440 av_masks += BITS_TO_LONGS(masklength);
441 }
442 return NULL;
443}
444
445static bool iio_validate_scan_mask(struct iio_dev *indio_dev,
446 const unsigned long *mask)
447{
448 if (!indio_dev->setup_ops->validate_scan_mask)
449 return true;
450
451 return indio_dev->setup_ops->validate_scan_mask(indio_dev, mask);
452}
453
454/**
455 * iio_scan_mask_set() - set particular bit in the scan mask
456 * @indio_dev: the iio device
457 * @buffer: the buffer whose scan mask we are interested in
458 * @bit: the bit to be set.
459 *
460 * Note that at this point we have no way of knowing what other
461 * buffers might request, hence this code only verifies that the
462 * individual buffers request is plausible.
463 */
464static int iio_scan_mask_set(struct iio_dev *indio_dev,
465 struct iio_buffer *buffer, int bit)
466{
467 const unsigned long *mask;
468 unsigned long *trialmask;
469
470 if (!indio_dev->masklength) {
471 WARN(1, "Trying to set scanmask prior to registering buffer\n");
472 return -EINVAL;
473 }
474
475 trialmask = bitmap_alloc(indio_dev->masklength, GFP_KERNEL);
476 if (!trialmask)
477 return -ENOMEM;
478 bitmap_copy(trialmask, buffer->scan_mask, indio_dev->masklength);
479 set_bit(bit, trialmask);
480
481 if (!iio_validate_scan_mask(indio_dev, trialmask))
482 goto err_invalid_mask;
483
484 if (indio_dev->available_scan_masks) {
485 mask = iio_scan_mask_match(indio_dev->available_scan_masks,
486 indio_dev->masklength,
487 trialmask, false);
488 if (!mask)
489 goto err_invalid_mask;
490 }
491 bitmap_copy(buffer->scan_mask, trialmask, indio_dev->masklength);
492
493 bitmap_free(trialmask);
494
495 return 0;
496
497err_invalid_mask:
498 bitmap_free(trialmask);
499 return -EINVAL;
500}
501
502static int iio_scan_mask_clear(struct iio_buffer *buffer, int bit)
503{
504 clear_bit(bit, buffer->scan_mask);
505 return 0;
506}
507
508static int iio_scan_mask_query(struct iio_dev *indio_dev,
509 struct iio_buffer *buffer, int bit)
510{
511 if (bit > indio_dev->masklength)
512 return -EINVAL;
513
514 if (!buffer->scan_mask)
515 return 0;
516
517 /* Ensure return value is 0 or 1. */
518 return !!test_bit(bit, buffer->scan_mask);
519};
520
521static ssize_t iio_scan_el_store(struct device *dev,
522 struct device_attribute *attr,
523 const char *buf,
524 size_t len)
525{
526 int ret;
527 bool state;
528 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
529 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
530 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
531 struct iio_buffer *buffer = this_attr->buffer;
532
533 ret = kstrtobool(buf, &state);
534 if (ret < 0)
535 return ret;
536 mutex_lock(&iio_dev_opaque->mlock);
537 if (iio_buffer_is_active(buffer)) {
538 ret = -EBUSY;
539 goto error_ret;
540 }
541 ret = iio_scan_mask_query(indio_dev, buffer, this_attr->address);
542 if (ret < 0)
543 goto error_ret;
544 if (!state && ret) {
545 ret = iio_scan_mask_clear(buffer, this_attr->address);
546 if (ret)
547 goto error_ret;
548 } else if (state && !ret) {
549 ret = iio_scan_mask_set(indio_dev, buffer, this_attr->address);
550 if (ret)
551 goto error_ret;
552 }
553
554error_ret:
555 mutex_unlock(&iio_dev_opaque->mlock);
556
557 return ret < 0 ? ret : len;
558}
559
560static ssize_t iio_scan_el_ts_show(struct device *dev,
561 struct device_attribute *attr,
562 char *buf)
563{
564 struct iio_buffer *buffer = to_iio_dev_attr(attr)->buffer;
565
566 return sysfs_emit(buf, "%d\n", buffer->scan_timestamp);
567}
568
569static ssize_t iio_scan_el_ts_store(struct device *dev,
570 struct device_attribute *attr,
571 const char *buf,
572 size_t len)
573{
574 int ret;
575 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
576 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
577 struct iio_buffer *buffer = to_iio_dev_attr(attr)->buffer;
578 bool state;
579
580 ret = kstrtobool(buf, &state);
581 if (ret < 0)
582 return ret;
583
584 mutex_lock(&iio_dev_opaque->mlock);
585 if (iio_buffer_is_active(buffer)) {
586 ret = -EBUSY;
587 goto error_ret;
588 }
589 buffer->scan_timestamp = state;
590error_ret:
591 mutex_unlock(&iio_dev_opaque->mlock);
592
593 return ret ? ret : len;
594}
595
596static int iio_buffer_add_channel_sysfs(struct iio_dev *indio_dev,
597 struct iio_buffer *buffer,
598 const struct iio_chan_spec *chan)
599{
600 int ret, attrcount = 0;
601
602 ret = __iio_add_chan_devattr("index",
603 chan,
604 &iio_show_scan_index,
605 NULL,
606 0,
607 IIO_SEPARATE,
608 &indio_dev->dev,
609 buffer,
610 &buffer->buffer_attr_list);
611 if (ret)
612 return ret;
613 attrcount++;
614 ret = __iio_add_chan_devattr("type",
615 chan,
616 &iio_show_fixed_type,
617 NULL,
618 0,
619 IIO_SEPARATE,
620 &indio_dev->dev,
621 buffer,
622 &buffer->buffer_attr_list);
623 if (ret)
624 return ret;
625 attrcount++;
626 if (chan->type != IIO_TIMESTAMP)
627 ret = __iio_add_chan_devattr("en",
628 chan,
629 &iio_scan_el_show,
630 &iio_scan_el_store,
631 chan->scan_index,
632 IIO_SEPARATE,
633 &indio_dev->dev,
634 buffer,
635 &buffer->buffer_attr_list);
636 else
637 ret = __iio_add_chan_devattr("en",
638 chan,
639 &iio_scan_el_ts_show,
640 &iio_scan_el_ts_store,
641 chan->scan_index,
642 IIO_SEPARATE,
643 &indio_dev->dev,
644 buffer,
645 &buffer->buffer_attr_list);
646 if (ret)
647 return ret;
648 attrcount++;
649 ret = attrcount;
650 return ret;
651}
652
653static ssize_t length_show(struct device *dev, struct device_attribute *attr,
654 char *buf)
655{
656 struct iio_buffer *buffer = to_iio_dev_attr(attr)->buffer;
657
658 return sysfs_emit(buf, "%d\n", buffer->length);
659}
660
661static ssize_t length_store(struct device *dev, struct device_attribute *attr,
662 const char *buf, size_t len)
663{
664 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
665 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
666 struct iio_buffer *buffer = to_iio_dev_attr(attr)->buffer;
667 unsigned int val;
668 int ret;
669
670 ret = kstrtouint(buf, 10, &val);
671 if (ret)
672 return ret;
673
674 if (val == buffer->length)
675 return len;
676
677 mutex_lock(&iio_dev_opaque->mlock);
678 if (iio_buffer_is_active(buffer)) {
679 ret = -EBUSY;
680 } else {
681 buffer->access->set_length(buffer, val);
682 ret = 0;
683 }
684 if (ret)
685 goto out;
686 if (buffer->length && buffer->length < buffer->watermark)
687 buffer->watermark = buffer->length;
688out:
689 mutex_unlock(&iio_dev_opaque->mlock);
690
691 return ret ? ret : len;
692}
693
694static ssize_t enable_show(struct device *dev, struct device_attribute *attr,
695 char *buf)
696{
697 struct iio_buffer *buffer = to_iio_dev_attr(attr)->buffer;
698
699 return sysfs_emit(buf, "%d\n", iio_buffer_is_active(buffer));
700}
701
702static unsigned int iio_storage_bytes_for_si(struct iio_dev *indio_dev,
703 unsigned int scan_index)
704{
705 const struct iio_chan_spec *ch;
706 unsigned int bytes;
707
708 ch = iio_find_channel_from_si(indio_dev, scan_index);
709 bytes = ch->scan_type.storagebits / 8;
710 if (ch->scan_type.repeat > 1)
711 bytes *= ch->scan_type.repeat;
712 return bytes;
713}
714
715static unsigned int iio_storage_bytes_for_timestamp(struct iio_dev *indio_dev)
716{
717 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
718
719 return iio_storage_bytes_for_si(indio_dev,
720 iio_dev_opaque->scan_index_timestamp);
721}
722
723static int iio_compute_scan_bytes(struct iio_dev *indio_dev,
724 const unsigned long *mask, bool timestamp)
725{
726 unsigned int bytes = 0;
727 int length, i, largest = 0;
728
729 /* How much space will the demuxed element take? */
730 for_each_set_bit(i, mask,
731 indio_dev->masklength) {
732 length = iio_storage_bytes_for_si(indio_dev, i);
733 bytes = ALIGN(bytes, length);
734 bytes += length;
735 largest = max(largest, length);
736 }
737
738 if (timestamp) {
739 length = iio_storage_bytes_for_timestamp(indio_dev);
740 bytes = ALIGN(bytes, length);
741 bytes += length;
742 largest = max(largest, length);
743 }
744
745 bytes = ALIGN(bytes, largest);
746 return bytes;
747}
748
749static void iio_buffer_activate(struct iio_dev *indio_dev,
750 struct iio_buffer *buffer)
751{
752 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
753
754 iio_buffer_get(buffer);
755 list_add(&buffer->buffer_list, &iio_dev_opaque->buffer_list);
756}
757
758static void iio_buffer_deactivate(struct iio_buffer *buffer)
759{
760 list_del_init(&buffer->buffer_list);
761 wake_up_interruptible(&buffer->pollq);
762 iio_buffer_put(buffer);
763}
764
765static void iio_buffer_deactivate_all(struct iio_dev *indio_dev)
766{
767 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
768 struct iio_buffer *buffer, *_buffer;
769
770 list_for_each_entry_safe(buffer, _buffer,
771 &iio_dev_opaque->buffer_list, buffer_list)
772 iio_buffer_deactivate(buffer);
773}
774
775static int iio_buffer_enable(struct iio_buffer *buffer,
776 struct iio_dev *indio_dev)
777{
778 if (!buffer->access->enable)
779 return 0;
780 return buffer->access->enable(buffer, indio_dev);
781}
782
783static int iio_buffer_disable(struct iio_buffer *buffer,
784 struct iio_dev *indio_dev)
785{
786 if (!buffer->access->disable)
787 return 0;
788 return buffer->access->disable(buffer, indio_dev);
789}
790
791static void iio_buffer_update_bytes_per_datum(struct iio_dev *indio_dev,
792 struct iio_buffer *buffer)
793{
794 unsigned int bytes;
795
796 if (!buffer->access->set_bytes_per_datum)
797 return;
798
799 bytes = iio_compute_scan_bytes(indio_dev, buffer->scan_mask,
800 buffer->scan_timestamp);
801
802 buffer->access->set_bytes_per_datum(buffer, bytes);
803}
804
805static int iio_buffer_request_update(struct iio_dev *indio_dev,
806 struct iio_buffer *buffer)
807{
808 int ret;
809
810 iio_buffer_update_bytes_per_datum(indio_dev, buffer);
811 if (buffer->access->request_update) {
812 ret = buffer->access->request_update(buffer);
813 if (ret) {
814 dev_dbg(&indio_dev->dev,
815 "Buffer not started: buffer parameter update failed (%d)\n",
816 ret);
817 return ret;
818 }
819 }
820
821 return 0;
822}
823
824static void iio_free_scan_mask(struct iio_dev *indio_dev,
825 const unsigned long *mask)
826{
827 /* If the mask is dynamically allocated free it, otherwise do nothing */
828 if (!indio_dev->available_scan_masks)
829 bitmap_free(mask);
830}
831
832struct iio_device_config {
833 unsigned int mode;
834 unsigned int watermark;
835 const unsigned long *scan_mask;
836 unsigned int scan_bytes;
837 bool scan_timestamp;
838};
839
840static int iio_verify_update(struct iio_dev *indio_dev,
841 struct iio_buffer *insert_buffer,
842 struct iio_buffer *remove_buffer,
843 struct iio_device_config *config)
844{
845 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
846 unsigned long *compound_mask;
847 const unsigned long *scan_mask;
848 bool strict_scanmask = false;
849 struct iio_buffer *buffer;
850 bool scan_timestamp;
851 unsigned int modes;
852
853 if (insert_buffer &&
854 bitmap_empty(insert_buffer->scan_mask, indio_dev->masklength)) {
855 dev_dbg(&indio_dev->dev,
856 "At least one scan element must be enabled first\n");
857 return -EINVAL;
858 }
859
860 memset(config, 0, sizeof(*config));
861 config->watermark = ~0;
862
863 /*
864 * If there is just one buffer and we are removing it there is nothing
865 * to verify.
866 */
867 if (remove_buffer && !insert_buffer &&
868 list_is_singular(&iio_dev_opaque->buffer_list))
869 return 0;
870
871 modes = indio_dev->modes;
872
873 list_for_each_entry(buffer, &iio_dev_opaque->buffer_list, buffer_list) {
874 if (buffer == remove_buffer)
875 continue;
876 modes &= buffer->access->modes;
877 config->watermark = min(config->watermark, buffer->watermark);
878 }
879
880 if (insert_buffer) {
881 modes &= insert_buffer->access->modes;
882 config->watermark = min(config->watermark,
883 insert_buffer->watermark);
884 }
885
886 /* Definitely possible for devices to support both of these. */
887 if ((modes & INDIO_BUFFER_TRIGGERED) && indio_dev->trig) {
888 config->mode = INDIO_BUFFER_TRIGGERED;
889 } else if (modes & INDIO_BUFFER_HARDWARE) {
890 /*
891 * Keep things simple for now and only allow a single buffer to
892 * be connected in hardware mode.
893 */
894 if (insert_buffer && !list_empty(&iio_dev_opaque->buffer_list))
895 return -EINVAL;
896 config->mode = INDIO_BUFFER_HARDWARE;
897 strict_scanmask = true;
898 } else if (modes & INDIO_BUFFER_SOFTWARE) {
899 config->mode = INDIO_BUFFER_SOFTWARE;
900 } else {
901 /* Can only occur on first buffer */
902 if (indio_dev->modes & INDIO_BUFFER_TRIGGERED)
903 dev_dbg(&indio_dev->dev, "Buffer not started: no trigger\n");
904 return -EINVAL;
905 }
906
907 /* What scan mask do we actually have? */
908 compound_mask = bitmap_zalloc(indio_dev->masklength, GFP_KERNEL);
909 if (!compound_mask)
910 return -ENOMEM;
911
912 scan_timestamp = false;
913
914 list_for_each_entry(buffer, &iio_dev_opaque->buffer_list, buffer_list) {
915 if (buffer == remove_buffer)
916 continue;
917 bitmap_or(compound_mask, compound_mask, buffer->scan_mask,
918 indio_dev->masklength);
919 scan_timestamp |= buffer->scan_timestamp;
920 }
921
922 if (insert_buffer) {
923 bitmap_or(compound_mask, compound_mask,
924 insert_buffer->scan_mask, indio_dev->masklength);
925 scan_timestamp |= insert_buffer->scan_timestamp;
926 }
927
928 if (indio_dev->available_scan_masks) {
929 scan_mask = iio_scan_mask_match(indio_dev->available_scan_masks,
930 indio_dev->masklength,
931 compound_mask,
932 strict_scanmask);
933 bitmap_free(compound_mask);
934 if (!scan_mask)
935 return -EINVAL;
936 } else {
937 scan_mask = compound_mask;
938 }
939
940 config->scan_bytes = iio_compute_scan_bytes(indio_dev,
941 scan_mask, scan_timestamp);
942 config->scan_mask = scan_mask;
943 config->scan_timestamp = scan_timestamp;
944
945 return 0;
946}
947
948/**
949 * struct iio_demux_table - table describing demux memcpy ops
950 * @from: index to copy from
951 * @to: index to copy to
952 * @length: how many bytes to copy
953 * @l: list head used for management
954 */
955struct iio_demux_table {
956 unsigned int from;
957 unsigned int to;
958 unsigned int length;
959 struct list_head l;
960};
961
962static void iio_buffer_demux_free(struct iio_buffer *buffer)
963{
964 struct iio_demux_table *p, *q;
965
966 list_for_each_entry_safe(p, q, &buffer->demux_list, l) {
967 list_del(&p->l);
968 kfree(p);
969 }
970}
971
972static int iio_buffer_add_demux(struct iio_buffer *buffer,
973 struct iio_demux_table **p, unsigned int in_loc,
974 unsigned int out_loc,
975 unsigned int length)
976{
977 if (*p && (*p)->from + (*p)->length == in_loc &&
978 (*p)->to + (*p)->length == out_loc) {
979 (*p)->length += length;
980 } else {
981 *p = kmalloc(sizeof(**p), GFP_KERNEL);
982 if (!(*p))
983 return -ENOMEM;
984 (*p)->from = in_loc;
985 (*p)->to = out_loc;
986 (*p)->length = length;
987 list_add_tail(&(*p)->l, &buffer->demux_list);
988 }
989
990 return 0;
991}
992
993static int iio_buffer_update_demux(struct iio_dev *indio_dev,
994 struct iio_buffer *buffer)
995{
996 int ret, in_ind = -1, out_ind, length;
997 unsigned int in_loc = 0, out_loc = 0;
998 struct iio_demux_table *p = NULL;
999
1000 /* Clear out any old demux */
1001 iio_buffer_demux_free(buffer);
1002 kfree(buffer->demux_bounce);
1003 buffer->demux_bounce = NULL;
1004
1005 /* First work out which scan mode we will actually have */
1006 if (bitmap_equal(indio_dev->active_scan_mask,
1007 buffer->scan_mask,
1008 indio_dev->masklength))
1009 return 0;
1010
1011 /* Now we have the two masks, work from least sig and build up sizes */
1012 for_each_set_bit(out_ind,
1013 buffer->scan_mask,
1014 indio_dev->masklength) {
1015 in_ind = find_next_bit(indio_dev->active_scan_mask,
1016 indio_dev->masklength,
1017 in_ind + 1);
1018 while (in_ind != out_ind) {
1019 length = iio_storage_bytes_for_si(indio_dev, in_ind);
1020 /* Make sure we are aligned */
1021 in_loc = roundup(in_loc, length) + length;
1022 in_ind = find_next_bit(indio_dev->active_scan_mask,
1023 indio_dev->masklength,
1024 in_ind + 1);
1025 }
1026 length = iio_storage_bytes_for_si(indio_dev, in_ind);
1027 out_loc = roundup(out_loc, length);
1028 in_loc = roundup(in_loc, length);
1029 ret = iio_buffer_add_demux(buffer, &p, in_loc, out_loc, length);
1030 if (ret)
1031 goto error_clear_mux_table;
1032 out_loc += length;
1033 in_loc += length;
1034 }
1035 /* Relies on scan_timestamp being last */
1036 if (buffer->scan_timestamp) {
1037 length = iio_storage_bytes_for_timestamp(indio_dev);
1038 out_loc = roundup(out_loc, length);
1039 in_loc = roundup(in_loc, length);
1040 ret = iio_buffer_add_demux(buffer, &p, in_loc, out_loc, length);
1041 if (ret)
1042 goto error_clear_mux_table;
1043 out_loc += length;
1044 }
1045 buffer->demux_bounce = kzalloc(out_loc, GFP_KERNEL);
1046 if (!buffer->demux_bounce) {
1047 ret = -ENOMEM;
1048 goto error_clear_mux_table;
1049 }
1050 return 0;
1051
1052error_clear_mux_table:
1053 iio_buffer_demux_free(buffer);
1054
1055 return ret;
1056}
1057
1058static int iio_update_demux(struct iio_dev *indio_dev)
1059{
1060 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
1061 struct iio_buffer *buffer;
1062 int ret;
1063
1064 list_for_each_entry(buffer, &iio_dev_opaque->buffer_list, buffer_list) {
1065 ret = iio_buffer_update_demux(indio_dev, buffer);
1066 if (ret < 0)
1067 goto error_clear_mux_table;
1068 }
1069 return 0;
1070
1071error_clear_mux_table:
1072 list_for_each_entry(buffer, &iio_dev_opaque->buffer_list, buffer_list)
1073 iio_buffer_demux_free(buffer);
1074
1075 return ret;
1076}
1077
1078static int iio_enable_buffers(struct iio_dev *indio_dev,
1079 struct iio_device_config *config)
1080{
1081 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
1082 struct iio_buffer *buffer, *tmp = NULL;
1083 int ret;
1084
1085 indio_dev->active_scan_mask = config->scan_mask;
1086 indio_dev->scan_timestamp = config->scan_timestamp;
1087 indio_dev->scan_bytes = config->scan_bytes;
1088 iio_dev_opaque->currentmode = config->mode;
1089
1090 iio_update_demux(indio_dev);
1091
1092 /* Wind up again */
1093 if (indio_dev->setup_ops->preenable) {
1094 ret = indio_dev->setup_ops->preenable(indio_dev);
1095 if (ret) {
1096 dev_dbg(&indio_dev->dev,
1097 "Buffer not started: buffer preenable failed (%d)\n", ret);
1098 goto err_undo_config;
1099 }
1100 }
1101
1102 if (indio_dev->info->update_scan_mode) {
1103 ret = indio_dev->info
1104 ->update_scan_mode(indio_dev,
1105 indio_dev->active_scan_mask);
1106 if (ret < 0) {
1107 dev_dbg(&indio_dev->dev,
1108 "Buffer not started: update scan mode failed (%d)\n",
1109 ret);
1110 goto err_run_postdisable;
1111 }
1112 }
1113
1114 if (indio_dev->info->hwfifo_set_watermark)
1115 indio_dev->info->hwfifo_set_watermark(indio_dev,
1116 config->watermark);
1117
1118 list_for_each_entry(buffer, &iio_dev_opaque->buffer_list, buffer_list) {
1119 ret = iio_buffer_enable(buffer, indio_dev);
1120 if (ret) {
1121 tmp = buffer;
1122 goto err_disable_buffers;
1123 }
1124 }
1125
1126 if (iio_dev_opaque->currentmode == INDIO_BUFFER_TRIGGERED) {
1127 ret = iio_trigger_attach_poll_func(indio_dev->trig,
1128 indio_dev->pollfunc);
1129 if (ret)
1130 goto err_disable_buffers;
1131 }
1132
1133 if (indio_dev->setup_ops->postenable) {
1134 ret = indio_dev->setup_ops->postenable(indio_dev);
1135 if (ret) {
1136 dev_dbg(&indio_dev->dev,
1137 "Buffer not started: postenable failed (%d)\n", ret);
1138 goto err_detach_pollfunc;
1139 }
1140 }
1141
1142 return 0;
1143
1144err_detach_pollfunc:
1145 if (iio_dev_opaque->currentmode == INDIO_BUFFER_TRIGGERED) {
1146 iio_trigger_detach_poll_func(indio_dev->trig,
1147 indio_dev->pollfunc);
1148 }
1149err_disable_buffers:
1150 buffer = list_prepare_entry(tmp, &iio_dev_opaque->buffer_list, buffer_list);
1151 list_for_each_entry_continue_reverse(buffer, &iio_dev_opaque->buffer_list,
1152 buffer_list)
1153 iio_buffer_disable(buffer, indio_dev);
1154err_run_postdisable:
1155 if (indio_dev->setup_ops->postdisable)
1156 indio_dev->setup_ops->postdisable(indio_dev);
1157err_undo_config:
1158 iio_dev_opaque->currentmode = INDIO_DIRECT_MODE;
1159 indio_dev->active_scan_mask = NULL;
1160
1161 return ret;
1162}
1163
1164static int iio_disable_buffers(struct iio_dev *indio_dev)
1165{
1166 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
1167 struct iio_buffer *buffer;
1168 int ret = 0;
1169 int ret2;
1170
1171 /* Wind down existing buffers - iff there are any */
1172 if (list_empty(&iio_dev_opaque->buffer_list))
1173 return 0;
1174
1175 /*
1176 * If things go wrong at some step in disable we still need to continue
1177 * to perform the other steps, otherwise we leave the device in a
1178 * inconsistent state. We return the error code for the first error we
1179 * encountered.
1180 */
1181
1182 if (indio_dev->setup_ops->predisable) {
1183 ret2 = indio_dev->setup_ops->predisable(indio_dev);
1184 if (ret2 && !ret)
1185 ret = ret2;
1186 }
1187
1188 if (iio_dev_opaque->currentmode == INDIO_BUFFER_TRIGGERED) {
1189 iio_trigger_detach_poll_func(indio_dev->trig,
1190 indio_dev->pollfunc);
1191 }
1192
1193 list_for_each_entry(buffer, &iio_dev_opaque->buffer_list, buffer_list) {
1194 ret2 = iio_buffer_disable(buffer, indio_dev);
1195 if (ret2 && !ret)
1196 ret = ret2;
1197 }
1198
1199 if (indio_dev->setup_ops->postdisable) {
1200 ret2 = indio_dev->setup_ops->postdisable(indio_dev);
1201 if (ret2 && !ret)
1202 ret = ret2;
1203 }
1204
1205 iio_free_scan_mask(indio_dev, indio_dev->active_scan_mask);
1206 indio_dev->active_scan_mask = NULL;
1207 iio_dev_opaque->currentmode = INDIO_DIRECT_MODE;
1208
1209 return ret;
1210}
1211
1212static int __iio_update_buffers(struct iio_dev *indio_dev,
1213 struct iio_buffer *insert_buffer,
1214 struct iio_buffer *remove_buffer)
1215{
1216 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
1217 struct iio_device_config new_config;
1218 int ret;
1219
1220 ret = iio_verify_update(indio_dev, insert_buffer, remove_buffer,
1221 &new_config);
1222 if (ret)
1223 return ret;
1224
1225 if (insert_buffer) {
1226 ret = iio_buffer_request_update(indio_dev, insert_buffer);
1227 if (ret)
1228 goto err_free_config;
1229 }
1230
1231 ret = iio_disable_buffers(indio_dev);
1232 if (ret)
1233 goto err_deactivate_all;
1234
1235 if (remove_buffer)
1236 iio_buffer_deactivate(remove_buffer);
1237 if (insert_buffer)
1238 iio_buffer_activate(indio_dev, insert_buffer);
1239
1240 /* If no buffers in list, we are done */
1241 if (list_empty(&iio_dev_opaque->buffer_list))
1242 return 0;
1243
1244 ret = iio_enable_buffers(indio_dev, &new_config);
1245 if (ret)
1246 goto err_deactivate_all;
1247
1248 return 0;
1249
1250err_deactivate_all:
1251 /*
1252 * We've already verified that the config is valid earlier. If things go
1253 * wrong in either enable or disable the most likely reason is an IO
1254 * error from the device. In this case there is no good recovery
1255 * strategy. Just make sure to disable everything and leave the device
1256 * in a sane state. With a bit of luck the device might come back to
1257 * life again later and userspace can try again.
1258 */
1259 iio_buffer_deactivate_all(indio_dev);
1260
1261err_free_config:
1262 iio_free_scan_mask(indio_dev, new_config.scan_mask);
1263 return ret;
1264}
1265
1266int iio_update_buffers(struct iio_dev *indio_dev,
1267 struct iio_buffer *insert_buffer,
1268 struct iio_buffer *remove_buffer)
1269{
1270 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
1271 int ret;
1272
1273 if (insert_buffer == remove_buffer)
1274 return 0;
1275
1276 if (insert_buffer &&
1277 insert_buffer->direction == IIO_BUFFER_DIRECTION_OUT)
1278 return -EINVAL;
1279
1280 mutex_lock(&iio_dev_opaque->info_exist_lock);
1281 mutex_lock(&iio_dev_opaque->mlock);
1282
1283 if (insert_buffer && iio_buffer_is_active(insert_buffer))
1284 insert_buffer = NULL;
1285
1286 if (remove_buffer && !iio_buffer_is_active(remove_buffer))
1287 remove_buffer = NULL;
1288
1289 if (!insert_buffer && !remove_buffer) {
1290 ret = 0;
1291 goto out_unlock;
1292 }
1293
1294 if (!indio_dev->info) {
1295 ret = -ENODEV;
1296 goto out_unlock;
1297 }
1298
1299 ret = __iio_update_buffers(indio_dev, insert_buffer, remove_buffer);
1300
1301out_unlock:
1302 mutex_unlock(&iio_dev_opaque->mlock);
1303 mutex_unlock(&iio_dev_opaque->info_exist_lock);
1304
1305 return ret;
1306}
1307EXPORT_SYMBOL_GPL(iio_update_buffers);
1308
1309void iio_disable_all_buffers(struct iio_dev *indio_dev)
1310{
1311 iio_disable_buffers(indio_dev);
1312 iio_buffer_deactivate_all(indio_dev);
1313}
1314
1315static ssize_t enable_store(struct device *dev, struct device_attribute *attr,
1316 const char *buf, size_t len)
1317{
1318 int ret;
1319 bool requested_state;
1320 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
1321 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
1322 struct iio_buffer *buffer = to_iio_dev_attr(attr)->buffer;
1323 bool inlist;
1324
1325 ret = kstrtobool(buf, &requested_state);
1326 if (ret < 0)
1327 return ret;
1328
1329 mutex_lock(&iio_dev_opaque->mlock);
1330
1331 /* Find out if it is in the list */
1332 inlist = iio_buffer_is_active(buffer);
1333 /* Already in desired state */
1334 if (inlist == requested_state)
1335 goto done;
1336
1337 if (requested_state)
1338 ret = __iio_update_buffers(indio_dev, buffer, NULL);
1339 else
1340 ret = __iio_update_buffers(indio_dev, NULL, buffer);
1341
1342done:
1343 mutex_unlock(&iio_dev_opaque->mlock);
1344 return (ret < 0) ? ret : len;
1345}
1346
1347static ssize_t watermark_show(struct device *dev, struct device_attribute *attr,
1348 char *buf)
1349{
1350 struct iio_buffer *buffer = to_iio_dev_attr(attr)->buffer;
1351
1352 return sysfs_emit(buf, "%u\n", buffer->watermark);
1353}
1354
1355static ssize_t watermark_store(struct device *dev,
1356 struct device_attribute *attr,
1357 const char *buf, size_t len)
1358{
1359 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
1360 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
1361 struct iio_buffer *buffer = to_iio_dev_attr(attr)->buffer;
1362 unsigned int val;
1363 int ret;
1364
1365 ret = kstrtouint(buf, 10, &val);
1366 if (ret)
1367 return ret;
1368 if (!val)
1369 return -EINVAL;
1370
1371 mutex_lock(&iio_dev_opaque->mlock);
1372
1373 if (val > buffer->length) {
1374 ret = -EINVAL;
1375 goto out;
1376 }
1377
1378 if (iio_buffer_is_active(buffer)) {
1379 ret = -EBUSY;
1380 goto out;
1381 }
1382
1383 buffer->watermark = val;
1384out:
1385 mutex_unlock(&iio_dev_opaque->mlock);
1386
1387 return ret ? ret : len;
1388}
1389
1390static ssize_t data_available_show(struct device *dev,
1391 struct device_attribute *attr, char *buf)
1392{
1393 struct iio_buffer *buffer = to_iio_dev_attr(attr)->buffer;
1394
1395 return sysfs_emit(buf, "%zu\n", iio_buffer_data_available(buffer));
1396}
1397
1398static ssize_t direction_show(struct device *dev,
1399 struct device_attribute *attr,
1400 char *buf)
1401{
1402 struct iio_buffer *buffer = to_iio_dev_attr(attr)->buffer;
1403
1404 switch (buffer->direction) {
1405 case IIO_BUFFER_DIRECTION_IN:
1406 return sysfs_emit(buf, "in\n");
1407 case IIO_BUFFER_DIRECTION_OUT:
1408 return sysfs_emit(buf, "out\n");
1409 default:
1410 return -EINVAL;
1411 }
1412}
1413
1414static DEVICE_ATTR_RW(length);
1415static struct device_attribute dev_attr_length_ro = __ATTR_RO(length);
1416static DEVICE_ATTR_RW(enable);
1417static DEVICE_ATTR_RW(watermark);
1418static struct device_attribute dev_attr_watermark_ro = __ATTR_RO(watermark);
1419static DEVICE_ATTR_RO(data_available);
1420static DEVICE_ATTR_RO(direction);
1421
1422/*
1423 * When adding new attributes here, put the at the end, at least until
1424 * the code that handles the length/length_ro & watermark/watermark_ro
1425 * assignments gets cleaned up. Otherwise these can create some weird
1426 * duplicate attributes errors under some setups.
1427 */
1428static struct attribute *iio_buffer_attrs[] = {
1429 &dev_attr_length.attr,
1430 &dev_attr_enable.attr,
1431 &dev_attr_watermark.attr,
1432 &dev_attr_data_available.attr,
1433 &dev_attr_direction.attr,
1434};
1435
1436#define to_dev_attr(_attr) container_of(_attr, struct device_attribute, attr)
1437
1438static struct attribute *iio_buffer_wrap_attr(struct iio_buffer *buffer,
1439 struct attribute *attr)
1440{
1441 struct device_attribute *dattr = to_dev_attr(attr);
1442 struct iio_dev_attr *iio_attr;
1443
1444 iio_attr = kzalloc(sizeof(*iio_attr), GFP_KERNEL);
1445 if (!iio_attr)
1446 return NULL;
1447
1448 iio_attr->buffer = buffer;
1449 memcpy(&iio_attr->dev_attr, dattr, sizeof(iio_attr->dev_attr));
1450 iio_attr->dev_attr.attr.name = kstrdup_const(attr->name, GFP_KERNEL);
1451 if (!iio_attr->dev_attr.attr.name) {
1452 kfree(iio_attr);
1453 return NULL;
1454 }
1455
1456 sysfs_attr_init(&iio_attr->dev_attr.attr);
1457
1458 list_add(&iio_attr->l, &buffer->buffer_attr_list);
1459
1460 return &iio_attr->dev_attr.attr;
1461}
1462
1463static int iio_buffer_register_legacy_sysfs_groups(struct iio_dev *indio_dev,
1464 struct attribute **buffer_attrs,
1465 int buffer_attrcount,
1466 int scan_el_attrcount)
1467{
1468 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
1469 struct attribute_group *group;
1470 struct attribute **attrs;
1471 int ret;
1472
1473 attrs = kcalloc(buffer_attrcount + 1, sizeof(*attrs), GFP_KERNEL);
1474 if (!attrs)
1475 return -ENOMEM;
1476
1477 memcpy(attrs, buffer_attrs, buffer_attrcount * sizeof(*attrs));
1478
1479 group = &iio_dev_opaque->legacy_buffer_group;
1480 group->attrs = attrs;
1481 group->name = "buffer";
1482
1483 ret = iio_device_register_sysfs_group(indio_dev, group);
1484 if (ret)
1485 goto error_free_buffer_attrs;
1486
1487 attrs = kcalloc(scan_el_attrcount + 1, sizeof(*attrs), GFP_KERNEL);
1488 if (!attrs) {
1489 ret = -ENOMEM;
1490 goto error_free_buffer_attrs;
1491 }
1492
1493 memcpy(attrs, &buffer_attrs[buffer_attrcount],
1494 scan_el_attrcount * sizeof(*attrs));
1495
1496 group = &iio_dev_opaque->legacy_scan_el_group;
1497 group->attrs = attrs;
1498 group->name = "scan_elements";
1499
1500 ret = iio_device_register_sysfs_group(indio_dev, group);
1501 if (ret)
1502 goto error_free_scan_el_attrs;
1503
1504 return 0;
1505
1506error_free_scan_el_attrs:
1507 kfree(iio_dev_opaque->legacy_scan_el_group.attrs);
1508error_free_buffer_attrs:
1509 kfree(iio_dev_opaque->legacy_buffer_group.attrs);
1510
1511 return ret;
1512}
1513
1514static void iio_buffer_unregister_legacy_sysfs_groups(struct iio_dev *indio_dev)
1515{
1516 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
1517
1518 kfree(iio_dev_opaque->legacy_buffer_group.attrs);
1519 kfree(iio_dev_opaque->legacy_scan_el_group.attrs);
1520}
1521
1522static int iio_buffer_chrdev_release(struct inode *inode, struct file *filep)
1523{
1524 struct iio_dev_buffer_pair *ib = filep->private_data;
1525 struct iio_dev *indio_dev = ib->indio_dev;
1526 struct iio_buffer *buffer = ib->buffer;
1527
1528 wake_up(&buffer->pollq);
1529
1530 kfree(ib);
1531 clear_bit(IIO_BUSY_BIT_POS, &buffer->flags);
1532 iio_device_put(indio_dev);
1533
1534 return 0;
1535}
1536
1537static const struct file_operations iio_buffer_chrdev_fileops = {
1538 .owner = THIS_MODULE,
1539 .llseek = noop_llseek,
1540 .read = iio_buffer_read,
1541 .write = iio_buffer_write,
1542 .poll = iio_buffer_poll,
1543 .release = iio_buffer_chrdev_release,
1544};
1545
1546static long iio_device_buffer_getfd(struct iio_dev *indio_dev, unsigned long arg)
1547{
1548 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
1549 int __user *ival = (int __user *)arg;
1550 struct iio_dev_buffer_pair *ib;
1551 struct iio_buffer *buffer;
1552 int fd, idx, ret;
1553
1554 if (copy_from_user(&idx, ival, sizeof(idx)))
1555 return -EFAULT;
1556
1557 if (idx >= iio_dev_opaque->attached_buffers_cnt)
1558 return -ENODEV;
1559
1560 iio_device_get(indio_dev);
1561
1562 buffer = iio_dev_opaque->attached_buffers[idx];
1563
1564 if (test_and_set_bit(IIO_BUSY_BIT_POS, &buffer->flags)) {
1565 ret = -EBUSY;
1566 goto error_iio_dev_put;
1567 }
1568
1569 ib = kzalloc(sizeof(*ib), GFP_KERNEL);
1570 if (!ib) {
1571 ret = -ENOMEM;
1572 goto error_clear_busy_bit;
1573 }
1574
1575 ib->indio_dev = indio_dev;
1576 ib->buffer = buffer;
1577
1578 fd = anon_inode_getfd("iio:buffer", &iio_buffer_chrdev_fileops,
1579 ib, O_RDWR | O_CLOEXEC);
1580 if (fd < 0) {
1581 ret = fd;
1582 goto error_free_ib;
1583 }
1584
1585 if (copy_to_user(ival, &fd, sizeof(fd))) {
1586 /*
1587 * "Leak" the fd, as there's not much we can do about this
1588 * anyway. 'fd' might have been closed already, as
1589 * anon_inode_getfd() called fd_install() on it, which made
1590 * it reachable by userland.
1591 *
1592 * Instead of allowing a malicious user to play tricks with
1593 * us, rely on the process exit path to do any necessary
1594 * cleanup, as in releasing the file, if still needed.
1595 */
1596 return -EFAULT;
1597 }
1598
1599 return 0;
1600
1601error_free_ib:
1602 kfree(ib);
1603error_clear_busy_bit:
1604 clear_bit(IIO_BUSY_BIT_POS, &buffer->flags);
1605error_iio_dev_put:
1606 iio_device_put(indio_dev);
1607 return ret;
1608}
1609
1610static long iio_device_buffer_ioctl(struct iio_dev *indio_dev, struct file *filp,
1611 unsigned int cmd, unsigned long arg)
1612{
1613 switch (cmd) {
1614 case IIO_BUFFER_GET_FD_IOCTL:
1615 return iio_device_buffer_getfd(indio_dev, arg);
1616 default:
1617 return IIO_IOCTL_UNHANDLED;
1618 }
1619}
1620
1621static int __iio_buffer_alloc_sysfs_and_mask(struct iio_buffer *buffer,
1622 struct iio_dev *indio_dev,
1623 int index)
1624{
1625 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
1626 struct iio_dev_attr *p;
1627 const struct iio_dev_attr *id_attr;
1628 struct attribute **attr;
1629 int ret, i, attrn, scan_el_attrcount, buffer_attrcount;
1630 const struct iio_chan_spec *channels;
1631
1632 buffer_attrcount = 0;
1633 if (buffer->attrs) {
1634 while (buffer->attrs[buffer_attrcount])
1635 buffer_attrcount++;
1636 }
1637 buffer_attrcount += ARRAY_SIZE(iio_buffer_attrs);
1638
1639 scan_el_attrcount = 0;
1640 INIT_LIST_HEAD(&buffer->buffer_attr_list);
1641 channels = indio_dev->channels;
1642 if (channels) {
1643 /* new magic */
1644 for (i = 0; i < indio_dev->num_channels; i++) {
1645 if (channels[i].scan_index < 0)
1646 continue;
1647
1648 /* Verify that sample bits fit into storage */
1649 if (channels[i].scan_type.storagebits <
1650 channels[i].scan_type.realbits +
1651 channels[i].scan_type.shift) {
1652 dev_err(&indio_dev->dev,
1653 "Channel %d storagebits (%d) < shifted realbits (%d + %d)\n",
1654 i, channels[i].scan_type.storagebits,
1655 channels[i].scan_type.realbits,
1656 channels[i].scan_type.shift);
1657 ret = -EINVAL;
1658 goto error_cleanup_dynamic;
1659 }
1660
1661 ret = iio_buffer_add_channel_sysfs(indio_dev, buffer,
1662 &channels[i]);
1663 if (ret < 0)
1664 goto error_cleanup_dynamic;
1665 scan_el_attrcount += ret;
1666 if (channels[i].type == IIO_TIMESTAMP)
1667 iio_dev_opaque->scan_index_timestamp =
1668 channels[i].scan_index;
1669 }
1670 if (indio_dev->masklength && !buffer->scan_mask) {
1671 buffer->scan_mask = bitmap_zalloc(indio_dev->masklength,
1672 GFP_KERNEL);
1673 if (!buffer->scan_mask) {
1674 ret = -ENOMEM;
1675 goto error_cleanup_dynamic;
1676 }
1677 }
1678 }
1679
1680 attrn = buffer_attrcount + scan_el_attrcount;
1681 attr = kcalloc(attrn + 1, sizeof(*attr), GFP_KERNEL);
1682 if (!attr) {
1683 ret = -ENOMEM;
1684 goto error_free_scan_mask;
1685 }
1686
1687 memcpy(attr, iio_buffer_attrs, sizeof(iio_buffer_attrs));
1688 if (!buffer->access->set_length)
1689 attr[0] = &dev_attr_length_ro.attr;
1690
1691 if (buffer->access->flags & INDIO_BUFFER_FLAG_FIXED_WATERMARK)
1692 attr[2] = &dev_attr_watermark_ro.attr;
1693
1694 if (buffer->attrs)
1695 for (i = 0, id_attr = buffer->attrs[i];
1696 (id_attr = buffer->attrs[i]); i++)
1697 attr[ARRAY_SIZE(iio_buffer_attrs) + i] =
1698 (struct attribute *)&id_attr->dev_attr.attr;
1699
1700 buffer->buffer_group.attrs = attr;
1701
1702 for (i = 0; i < buffer_attrcount; i++) {
1703 struct attribute *wrapped;
1704
1705 wrapped = iio_buffer_wrap_attr(buffer, attr[i]);
1706 if (!wrapped) {
1707 ret = -ENOMEM;
1708 goto error_free_buffer_attrs;
1709 }
1710 attr[i] = wrapped;
1711 }
1712
1713 attrn = 0;
1714 list_for_each_entry(p, &buffer->buffer_attr_list, l)
1715 attr[attrn++] = &p->dev_attr.attr;
1716
1717 buffer->buffer_group.name = kasprintf(GFP_KERNEL, "buffer%d", index);
1718 if (!buffer->buffer_group.name) {
1719 ret = -ENOMEM;
1720 goto error_free_buffer_attrs;
1721 }
1722
1723 ret = iio_device_register_sysfs_group(indio_dev, &buffer->buffer_group);
1724 if (ret)
1725 goto error_free_buffer_attr_group_name;
1726
1727 /* we only need to register the legacy groups for the first buffer */
1728 if (index > 0)
1729 return 0;
1730
1731 ret = iio_buffer_register_legacy_sysfs_groups(indio_dev, attr,
1732 buffer_attrcount,
1733 scan_el_attrcount);
1734 if (ret)
1735 goto error_free_buffer_attr_group_name;
1736
1737 return 0;
1738
1739error_free_buffer_attr_group_name:
1740 kfree(buffer->buffer_group.name);
1741error_free_buffer_attrs:
1742 kfree(buffer->buffer_group.attrs);
1743error_free_scan_mask:
1744 bitmap_free(buffer->scan_mask);
1745error_cleanup_dynamic:
1746 iio_free_chan_devattr_list(&buffer->buffer_attr_list);
1747
1748 return ret;
1749}
1750
1751static void __iio_buffer_free_sysfs_and_mask(struct iio_buffer *buffer,
1752 struct iio_dev *indio_dev,
1753 int index)
1754{
1755 if (index == 0)
1756 iio_buffer_unregister_legacy_sysfs_groups(indio_dev);
1757 bitmap_free(buffer->scan_mask);
1758 kfree(buffer->buffer_group.name);
1759 kfree(buffer->buffer_group.attrs);
1760 iio_free_chan_devattr_list(&buffer->buffer_attr_list);
1761}
1762
1763int iio_buffers_alloc_sysfs_and_mask(struct iio_dev *indio_dev)
1764{
1765 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
1766 const struct iio_chan_spec *channels;
1767 struct iio_buffer *buffer;
1768 int ret, i, idx;
1769 size_t sz;
1770
1771 channels = indio_dev->channels;
1772 if (channels) {
1773 int ml = indio_dev->masklength;
1774
1775 for (i = 0; i < indio_dev->num_channels; i++)
1776 ml = max(ml, channels[i].scan_index + 1);
1777 indio_dev->masklength = ml;
1778 }
1779
1780 if (!iio_dev_opaque->attached_buffers_cnt)
1781 return 0;
1782
1783 for (idx = 0; idx < iio_dev_opaque->attached_buffers_cnt; idx++) {
1784 buffer = iio_dev_opaque->attached_buffers[idx];
1785 ret = __iio_buffer_alloc_sysfs_and_mask(buffer, indio_dev, idx);
1786 if (ret)
1787 goto error_unwind_sysfs_and_mask;
1788 }
1789
1790 sz = sizeof(*iio_dev_opaque->buffer_ioctl_handler);
1791 iio_dev_opaque->buffer_ioctl_handler = kzalloc(sz, GFP_KERNEL);
1792 if (!iio_dev_opaque->buffer_ioctl_handler) {
1793 ret = -ENOMEM;
1794 goto error_unwind_sysfs_and_mask;
1795 }
1796
1797 iio_dev_opaque->buffer_ioctl_handler->ioctl = iio_device_buffer_ioctl;
1798 iio_device_ioctl_handler_register(indio_dev,
1799 iio_dev_opaque->buffer_ioctl_handler);
1800
1801 return 0;
1802
1803error_unwind_sysfs_and_mask:
1804 while (idx--) {
1805 buffer = iio_dev_opaque->attached_buffers[idx];
1806 __iio_buffer_free_sysfs_and_mask(buffer, indio_dev, idx);
1807 }
1808 return ret;
1809}
1810
1811void iio_buffers_free_sysfs_and_mask(struct iio_dev *indio_dev)
1812{
1813 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
1814 struct iio_buffer *buffer;
1815 int i;
1816
1817 if (!iio_dev_opaque->attached_buffers_cnt)
1818 return;
1819
1820 iio_device_ioctl_handler_unregister(iio_dev_opaque->buffer_ioctl_handler);
1821 kfree(iio_dev_opaque->buffer_ioctl_handler);
1822
1823 for (i = iio_dev_opaque->attached_buffers_cnt - 1; i >= 0; i--) {
1824 buffer = iio_dev_opaque->attached_buffers[i];
1825 __iio_buffer_free_sysfs_and_mask(buffer, indio_dev, i);
1826 }
1827}
1828
1829/**
1830 * iio_validate_scan_mask_onehot() - Validates that exactly one channel is selected
1831 * @indio_dev: the iio device
1832 * @mask: scan mask to be checked
1833 *
1834 * Return true if exactly one bit is set in the scan mask, false otherwise. It
1835 * can be used for devices where only one channel can be active for sampling at
1836 * a time.
1837 */
1838bool iio_validate_scan_mask_onehot(struct iio_dev *indio_dev,
1839 const unsigned long *mask)
1840{
1841 return bitmap_weight(mask, indio_dev->masklength) == 1;
1842}
1843EXPORT_SYMBOL_GPL(iio_validate_scan_mask_onehot);
1844
1845static const void *iio_demux(struct iio_buffer *buffer,
1846 const void *datain)
1847{
1848 struct iio_demux_table *t;
1849
1850 if (list_empty(&buffer->demux_list))
1851 return datain;
1852 list_for_each_entry(t, &buffer->demux_list, l)
1853 memcpy(buffer->demux_bounce + t->to,
1854 datain + t->from, t->length);
1855
1856 return buffer->demux_bounce;
1857}
1858
1859static int iio_push_to_buffer(struct iio_buffer *buffer, const void *data)
1860{
1861 const void *dataout = iio_demux(buffer, data);
1862 int ret;
1863
1864 ret = buffer->access->store_to(buffer, dataout);
1865 if (ret)
1866 return ret;
1867
1868 /*
1869 * We can't just test for watermark to decide if we wake the poll queue
1870 * because read may request less samples than the watermark.
1871 */
1872 wake_up_interruptible_poll(&buffer->pollq, EPOLLIN | EPOLLRDNORM);
1873 return 0;
1874}
1875
1876/**
1877 * iio_push_to_buffers() - push to a registered buffer.
1878 * @indio_dev: iio_dev structure for device.
1879 * @data: Full scan.
1880 */
1881int iio_push_to_buffers(struct iio_dev *indio_dev, const void *data)
1882{
1883 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
1884 int ret;
1885 struct iio_buffer *buf;
1886
1887 list_for_each_entry(buf, &iio_dev_opaque->buffer_list, buffer_list) {
1888 ret = iio_push_to_buffer(buf, data);
1889 if (ret < 0)
1890 return ret;
1891 }
1892
1893 return 0;
1894}
1895EXPORT_SYMBOL_GPL(iio_push_to_buffers);
1896
1897/**
1898 * iio_push_to_buffers_with_ts_unaligned() - push to registered buffer,
1899 * no alignment or space requirements.
1900 * @indio_dev: iio_dev structure for device.
1901 * @data: channel data excluding the timestamp.
1902 * @data_sz: size of data.
1903 * @timestamp: timestamp for the sample data.
1904 *
1905 * This special variant of iio_push_to_buffers_with_timestamp() does
1906 * not require space for the timestamp, or 8 byte alignment of data.
1907 * It does however require an allocation on first call and additional
1908 * copies on all calls, so should be avoided if possible.
1909 */
1910int iio_push_to_buffers_with_ts_unaligned(struct iio_dev *indio_dev,
1911 const void *data,
1912 size_t data_sz,
1913 int64_t timestamp)
1914{
1915 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
1916
1917 /*
1918 * Conservative estimate - we can always safely copy the minimum
1919 * of either the data provided or the length of the destination buffer.
1920 * This relaxed limit allows the calling drivers to be lax about
1921 * tracking the size of the data they are pushing, at the cost of
1922 * unnecessary copying of padding.
1923 */
1924 data_sz = min_t(size_t, indio_dev->scan_bytes, data_sz);
1925 if (iio_dev_opaque->bounce_buffer_size != indio_dev->scan_bytes) {
1926 void *bb;
1927
1928 bb = devm_krealloc(&indio_dev->dev,
1929 iio_dev_opaque->bounce_buffer,
1930 indio_dev->scan_bytes, GFP_KERNEL);
1931 if (!bb)
1932 return -ENOMEM;
1933 iio_dev_opaque->bounce_buffer = bb;
1934 iio_dev_opaque->bounce_buffer_size = indio_dev->scan_bytes;
1935 }
1936 memcpy(iio_dev_opaque->bounce_buffer, data, data_sz);
1937 return iio_push_to_buffers_with_timestamp(indio_dev,
1938 iio_dev_opaque->bounce_buffer,
1939 timestamp);
1940}
1941EXPORT_SYMBOL_GPL(iio_push_to_buffers_with_ts_unaligned);
1942
1943/**
1944 * iio_buffer_release() - Free a buffer's resources
1945 * @ref: Pointer to the kref embedded in the iio_buffer struct
1946 *
1947 * This function is called when the last reference to the buffer has been
1948 * dropped. It will typically free all resources allocated by the buffer. Do not
1949 * call this function manually, always use iio_buffer_put() when done using a
1950 * buffer.
1951 */
1952static void iio_buffer_release(struct kref *ref)
1953{
1954 struct iio_buffer *buffer = container_of(ref, struct iio_buffer, ref);
1955
1956 buffer->access->release(buffer);
1957}
1958
1959/**
1960 * iio_buffer_get() - Grab a reference to the buffer
1961 * @buffer: The buffer to grab a reference for, may be NULL
1962 *
1963 * Returns the pointer to the buffer that was passed into the function.
1964 */
1965struct iio_buffer *iio_buffer_get(struct iio_buffer *buffer)
1966{
1967 if (buffer)
1968 kref_get(&buffer->ref);
1969
1970 return buffer;
1971}
1972EXPORT_SYMBOL_GPL(iio_buffer_get);
1973
1974/**
1975 * iio_buffer_put() - Release the reference to the buffer
1976 * @buffer: The buffer to release the reference for, may be NULL
1977 */
1978void iio_buffer_put(struct iio_buffer *buffer)
1979{
1980 if (buffer)
1981 kref_put(&buffer->ref, iio_buffer_release);
1982}
1983EXPORT_SYMBOL_GPL(iio_buffer_put);
1984
1985/**
1986 * iio_device_attach_buffer - Attach a buffer to a IIO device
1987 * @indio_dev: The device the buffer should be attached to
1988 * @buffer: The buffer to attach to the device
1989 *
1990 * Return 0 if successful, negative if error.
1991 *
1992 * This function attaches a buffer to a IIO device. The buffer stays attached to
1993 * the device until the device is freed. For legacy reasons, the first attached
1994 * buffer will also be assigned to 'indio_dev->buffer'.
1995 * The array allocated here, will be free'd via the iio_device_detach_buffers()
1996 * call which is handled by the iio_device_free().
1997 */
1998int iio_device_attach_buffer(struct iio_dev *indio_dev,
1999 struct iio_buffer *buffer)
2000{
2001 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
2002 struct iio_buffer **new, **old = iio_dev_opaque->attached_buffers;
2003 unsigned int cnt = iio_dev_opaque->attached_buffers_cnt;
2004
2005 cnt++;
2006
2007 new = krealloc(old, sizeof(*new) * cnt, GFP_KERNEL);
2008 if (!new)
2009 return -ENOMEM;
2010 iio_dev_opaque->attached_buffers = new;
2011
2012 buffer = iio_buffer_get(buffer);
2013
2014 /* first buffer is legacy; attach it to the IIO device directly */
2015 if (!indio_dev->buffer)
2016 indio_dev->buffer = buffer;
2017
2018 iio_dev_opaque->attached_buffers[cnt - 1] = buffer;
2019 iio_dev_opaque->attached_buffers_cnt = cnt;
2020
2021 return 0;
2022}
2023EXPORT_SYMBOL_GPL(iio_device_attach_buffer);