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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/* The industrial I/O core
2 *
3 * Copyright (c) 2008 Jonathan Cameron
4 *
5 * This program is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 as published by
7 * the Free Software Foundation.
8 *
9 * Handling of buffer allocation / resizing.
10 *
11 *
12 * Things to look at here.
13 * - Better memory allocation techniques?
14 * - Alternative access techniques?
15 */
16#include <linux/kernel.h>
17#include <linux/export.h>
18#include <linux/device.h>
19#include <linux/fs.h>
20#include <linux/cdev.h>
21#include <linux/slab.h>
22#include <linux/poll.h>
23#include <linux/sched.h>
24
25#include <linux/iio/iio.h>
26#include "iio_core.h"
27#include <linux/iio/sysfs.h>
28#include <linux/iio/buffer.h>
29
30static const char * const iio_endian_prefix[] = {
31 [IIO_BE] = "be",
32 [IIO_LE] = "le",
33};
34
35static bool iio_buffer_is_active(struct iio_buffer *buf)
36{
37 return !list_empty(&buf->buffer_list);
38}
39
40static size_t iio_buffer_data_available(struct iio_buffer *buf)
41{
42 return buf->access->data_available(buf);
43}
44
45static int iio_buffer_flush_hwfifo(struct iio_dev *indio_dev,
46 struct iio_buffer *buf, size_t required)
47{
48 if (!indio_dev->info->hwfifo_flush_to_buffer)
49 return -ENODEV;
50
51 return indio_dev->info->hwfifo_flush_to_buffer(indio_dev, required);
52}
53
54static bool iio_buffer_ready(struct iio_dev *indio_dev, struct iio_buffer *buf,
55 size_t to_wait, int to_flush)
56{
57 size_t avail;
58 int flushed = 0;
59
60 /* wakeup if the device was unregistered */
61 if (!indio_dev->info)
62 return true;
63
64 /* drain the buffer if it was disabled */
65 if (!iio_buffer_is_active(buf)) {
66 to_wait = min_t(size_t, to_wait, 1);
67 to_flush = 0;
68 }
69
70 avail = iio_buffer_data_available(buf);
71
72 if (avail >= to_wait) {
73 /* force a flush for non-blocking reads */
74 if (!to_wait && avail < to_flush)
75 iio_buffer_flush_hwfifo(indio_dev, buf,
76 to_flush - avail);
77 return true;
78 }
79
80 if (to_flush)
81 flushed = iio_buffer_flush_hwfifo(indio_dev, buf,
82 to_wait - avail);
83 if (flushed <= 0)
84 return false;
85
86 if (avail + flushed >= to_wait)
87 return true;
88
89 return false;
90}
91
92/**
93 * iio_buffer_read_first_n_outer() - chrdev read for buffer access
94 * @filp: File structure pointer for the char device
95 * @buf: Destination buffer for iio buffer read
96 * @n: First n bytes to read
97 * @f_ps: Long offset provided by the user as a seek position
98 *
99 * This function relies on all buffer implementations having an
100 * iio_buffer as their first element.
101 *
102 * Return: negative values corresponding to error codes or ret != 0
103 * for ending the reading activity
104 **/
105ssize_t iio_buffer_read_first_n_outer(struct file *filp, char __user *buf,
106 size_t n, loff_t *f_ps)
107{
108 struct iio_dev *indio_dev = filp->private_data;
109 struct iio_buffer *rb = indio_dev->buffer;
110 size_t datum_size;
111 size_t to_wait;
112 int ret;
113
114 if (!indio_dev->info)
115 return -ENODEV;
116
117 if (!rb || !rb->access->read_first_n)
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 do {
135 ret = wait_event_interruptible(rb->pollq,
136 iio_buffer_ready(indio_dev, rb, to_wait, n / datum_size));
137 if (ret)
138 return ret;
139
140 if (!indio_dev->info)
141 return -ENODEV;
142
143 ret = rb->access->read_first_n(rb, n, buf);
144 if (ret == 0 && (filp->f_flags & O_NONBLOCK))
145 ret = -EAGAIN;
146 } while (ret == 0);
147
148 return ret;
149}
150
151/**
152 * iio_buffer_poll() - poll the buffer to find out if it has data
153 * @filp: File structure pointer for device access
154 * @wait: Poll table structure pointer for which the driver adds
155 * a wait queue
156 *
157 * Return: (POLLIN | POLLRDNORM) if data is available for reading
158 * or 0 for other cases
159 */
160unsigned int iio_buffer_poll(struct file *filp,
161 struct poll_table_struct *wait)
162{
163 struct iio_dev *indio_dev = filp->private_data;
164 struct iio_buffer *rb = indio_dev->buffer;
165
166 if (!indio_dev->info)
167 return 0;
168
169 poll_wait(filp, &rb->pollq, wait);
170 if (iio_buffer_ready(indio_dev, rb, rb->watermark, 0))
171 return POLLIN | POLLRDNORM;
172 return 0;
173}
174
175/**
176 * iio_buffer_wakeup_poll - Wakes up the buffer waitqueue
177 * @indio_dev: The IIO device
178 *
179 * Wakes up the event waitqueue used for poll(). Should usually
180 * be called when the device is unregistered.
181 */
182void iio_buffer_wakeup_poll(struct iio_dev *indio_dev)
183{
184 if (!indio_dev->buffer)
185 return;
186
187 wake_up(&indio_dev->buffer->pollq);
188}
189
190void iio_buffer_init(struct iio_buffer *buffer)
191{
192 INIT_LIST_HEAD(&buffer->demux_list);
193 INIT_LIST_HEAD(&buffer->buffer_list);
194 init_waitqueue_head(&buffer->pollq);
195 kref_init(&buffer->ref);
196 if (!buffer->watermark)
197 buffer->watermark = 1;
198}
199EXPORT_SYMBOL(iio_buffer_init);
200
201static ssize_t iio_show_scan_index(struct device *dev,
202 struct device_attribute *attr,
203 char *buf)
204{
205 return sprintf(buf, "%u\n", to_iio_dev_attr(attr)->c->scan_index);
206}
207
208static ssize_t iio_show_fixed_type(struct device *dev,
209 struct device_attribute *attr,
210 char *buf)
211{
212 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
213 u8 type = this_attr->c->scan_type.endianness;
214
215 if (type == IIO_CPU) {
216#ifdef __LITTLE_ENDIAN
217 type = IIO_LE;
218#else
219 type = IIO_BE;
220#endif
221 }
222 if (this_attr->c->scan_type.repeat > 1)
223 return sprintf(buf, "%s:%c%d/%dX%d>>%u\n",
224 iio_endian_prefix[type],
225 this_attr->c->scan_type.sign,
226 this_attr->c->scan_type.realbits,
227 this_attr->c->scan_type.storagebits,
228 this_attr->c->scan_type.repeat,
229 this_attr->c->scan_type.shift);
230 else
231 return sprintf(buf, "%s:%c%d/%d>>%u\n",
232 iio_endian_prefix[type],
233 this_attr->c->scan_type.sign,
234 this_attr->c->scan_type.realbits,
235 this_attr->c->scan_type.storagebits,
236 this_attr->c->scan_type.shift);
237}
238
239static ssize_t iio_scan_el_show(struct device *dev,
240 struct device_attribute *attr,
241 char *buf)
242{
243 int ret;
244 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
245
246 /* Ensure ret is 0 or 1. */
247 ret = !!test_bit(to_iio_dev_attr(attr)->address,
248 indio_dev->buffer->scan_mask);
249
250 return sprintf(buf, "%d\n", ret);
251}
252
253/* Note NULL used as error indicator as it doesn't make sense. */
254static const unsigned long *iio_scan_mask_match(const unsigned long *av_masks,
255 unsigned int masklength,
256 const unsigned long *mask,
257 bool strict)
258{
259 if (bitmap_empty(mask, masklength))
260 return NULL;
261 while (*av_masks) {
262 if (strict) {
263 if (bitmap_equal(mask, av_masks, masklength))
264 return av_masks;
265 } else {
266 if (bitmap_subset(mask, av_masks, masklength))
267 return av_masks;
268 }
269 av_masks += BITS_TO_LONGS(masklength);
270 }
271 return NULL;
272}
273
274static bool iio_validate_scan_mask(struct iio_dev *indio_dev,
275 const unsigned long *mask)
276{
277 if (!indio_dev->setup_ops->validate_scan_mask)
278 return true;
279
280 return indio_dev->setup_ops->validate_scan_mask(indio_dev, mask);
281}
282
283/**
284 * iio_scan_mask_set() - set particular bit in the scan mask
285 * @indio_dev: the iio device
286 * @buffer: the buffer whose scan mask we are interested in
287 * @bit: the bit to be set.
288 *
289 * Note that at this point we have no way of knowing what other
290 * buffers might request, hence this code only verifies that the
291 * individual buffers request is plausible.
292 */
293static int iio_scan_mask_set(struct iio_dev *indio_dev,
294 struct iio_buffer *buffer, int bit)
295{
296 const unsigned long *mask;
297 unsigned long *trialmask;
298
299 trialmask = kmalloc(sizeof(*trialmask)*
300 BITS_TO_LONGS(indio_dev->masklength),
301 GFP_KERNEL);
302
303 if (trialmask == NULL)
304 return -ENOMEM;
305 if (!indio_dev->masklength) {
306 WARN(1, "Trying to set scanmask prior to registering buffer\n");
307 goto err_invalid_mask;
308 }
309 bitmap_copy(trialmask, buffer->scan_mask, indio_dev->masklength);
310 set_bit(bit, trialmask);
311
312 if (!iio_validate_scan_mask(indio_dev, trialmask))
313 goto err_invalid_mask;
314
315 if (indio_dev->available_scan_masks) {
316 mask = iio_scan_mask_match(indio_dev->available_scan_masks,
317 indio_dev->masklength,
318 trialmask, false);
319 if (!mask)
320 goto err_invalid_mask;
321 }
322 bitmap_copy(buffer->scan_mask, trialmask, indio_dev->masklength);
323
324 kfree(trialmask);
325
326 return 0;
327
328err_invalid_mask:
329 kfree(trialmask);
330 return -EINVAL;
331}
332
333static int iio_scan_mask_clear(struct iio_buffer *buffer, int bit)
334{
335 clear_bit(bit, buffer->scan_mask);
336 return 0;
337}
338
339static ssize_t iio_scan_el_store(struct device *dev,
340 struct device_attribute *attr,
341 const char *buf,
342 size_t len)
343{
344 int ret;
345 bool state;
346 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
347 struct iio_buffer *buffer = indio_dev->buffer;
348 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
349
350 ret = strtobool(buf, &state);
351 if (ret < 0)
352 return ret;
353 mutex_lock(&indio_dev->mlock);
354 if (iio_buffer_is_active(indio_dev->buffer)) {
355 ret = -EBUSY;
356 goto error_ret;
357 }
358 ret = iio_scan_mask_query(indio_dev, buffer, this_attr->address);
359 if (ret < 0)
360 goto error_ret;
361 if (!state && ret) {
362 ret = iio_scan_mask_clear(buffer, this_attr->address);
363 if (ret)
364 goto error_ret;
365 } else if (state && !ret) {
366 ret = iio_scan_mask_set(indio_dev, buffer, this_attr->address);
367 if (ret)
368 goto error_ret;
369 }
370
371error_ret:
372 mutex_unlock(&indio_dev->mlock);
373
374 return ret < 0 ? ret : len;
375
376}
377
378static ssize_t iio_scan_el_ts_show(struct device *dev,
379 struct device_attribute *attr,
380 char *buf)
381{
382 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
383 return sprintf(buf, "%d\n", indio_dev->buffer->scan_timestamp);
384}
385
386static ssize_t iio_scan_el_ts_store(struct device *dev,
387 struct device_attribute *attr,
388 const char *buf,
389 size_t len)
390{
391 int ret;
392 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
393 bool state;
394
395 ret = strtobool(buf, &state);
396 if (ret < 0)
397 return ret;
398
399 mutex_lock(&indio_dev->mlock);
400 if (iio_buffer_is_active(indio_dev->buffer)) {
401 ret = -EBUSY;
402 goto error_ret;
403 }
404 indio_dev->buffer->scan_timestamp = state;
405error_ret:
406 mutex_unlock(&indio_dev->mlock);
407
408 return ret ? ret : len;
409}
410
411static int iio_buffer_add_channel_sysfs(struct iio_dev *indio_dev,
412 const struct iio_chan_spec *chan)
413{
414 int ret, attrcount = 0;
415 struct iio_buffer *buffer = indio_dev->buffer;
416
417 ret = __iio_add_chan_devattr("index",
418 chan,
419 &iio_show_scan_index,
420 NULL,
421 0,
422 IIO_SEPARATE,
423 &indio_dev->dev,
424 &buffer->scan_el_dev_attr_list);
425 if (ret)
426 return ret;
427 attrcount++;
428 ret = __iio_add_chan_devattr("type",
429 chan,
430 &iio_show_fixed_type,
431 NULL,
432 0,
433 0,
434 &indio_dev->dev,
435 &buffer->scan_el_dev_attr_list);
436 if (ret)
437 return ret;
438 attrcount++;
439 if (chan->type != IIO_TIMESTAMP)
440 ret = __iio_add_chan_devattr("en",
441 chan,
442 &iio_scan_el_show,
443 &iio_scan_el_store,
444 chan->scan_index,
445 0,
446 &indio_dev->dev,
447 &buffer->scan_el_dev_attr_list);
448 else
449 ret = __iio_add_chan_devattr("en",
450 chan,
451 &iio_scan_el_ts_show,
452 &iio_scan_el_ts_store,
453 chan->scan_index,
454 0,
455 &indio_dev->dev,
456 &buffer->scan_el_dev_attr_list);
457 if (ret)
458 return ret;
459 attrcount++;
460 ret = attrcount;
461 return ret;
462}
463
464static ssize_t iio_buffer_read_length(struct device *dev,
465 struct device_attribute *attr,
466 char *buf)
467{
468 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
469 struct iio_buffer *buffer = indio_dev->buffer;
470
471 return sprintf(buf, "%d\n", buffer->length);
472}
473
474static ssize_t iio_buffer_write_length(struct device *dev,
475 struct device_attribute *attr,
476 const char *buf, size_t len)
477{
478 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
479 struct iio_buffer *buffer = indio_dev->buffer;
480 unsigned int val;
481 int ret;
482
483 ret = kstrtouint(buf, 10, &val);
484 if (ret)
485 return ret;
486
487 if (val == buffer->length)
488 return len;
489
490 mutex_lock(&indio_dev->mlock);
491 if (iio_buffer_is_active(indio_dev->buffer)) {
492 ret = -EBUSY;
493 } else {
494 buffer->access->set_length(buffer, val);
495 ret = 0;
496 }
497 if (ret)
498 goto out;
499 if (buffer->length && buffer->length < buffer->watermark)
500 buffer->watermark = buffer->length;
501out:
502 mutex_unlock(&indio_dev->mlock);
503
504 return ret ? ret : len;
505}
506
507static ssize_t iio_buffer_show_enable(struct device *dev,
508 struct device_attribute *attr,
509 char *buf)
510{
511 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
512 return sprintf(buf, "%d\n", iio_buffer_is_active(indio_dev->buffer));
513}
514
515static unsigned int iio_storage_bytes_for_si(struct iio_dev *indio_dev,
516 unsigned int scan_index)
517{
518 const struct iio_chan_spec *ch;
519 unsigned int bytes;
520
521 ch = iio_find_channel_from_si(indio_dev, scan_index);
522 bytes = ch->scan_type.storagebits / 8;
523 if (ch->scan_type.repeat > 1)
524 bytes *= ch->scan_type.repeat;
525 return bytes;
526}
527
528static unsigned int iio_storage_bytes_for_timestamp(struct iio_dev *indio_dev)
529{
530 return iio_storage_bytes_for_si(indio_dev,
531 indio_dev->scan_index_timestamp);
532}
533
534static int iio_compute_scan_bytes(struct iio_dev *indio_dev,
535 const unsigned long *mask, bool timestamp)
536{
537 unsigned bytes = 0;
538 int length, i;
539
540 /* How much space will the demuxed element take? */
541 for_each_set_bit(i, mask,
542 indio_dev->masklength) {
543 length = iio_storage_bytes_for_si(indio_dev, i);
544 bytes = ALIGN(bytes, length);
545 bytes += length;
546 }
547
548 if (timestamp) {
549 length = iio_storage_bytes_for_timestamp(indio_dev);
550 bytes = ALIGN(bytes, length);
551 bytes += length;
552 }
553 return bytes;
554}
555
556static void iio_buffer_activate(struct iio_dev *indio_dev,
557 struct iio_buffer *buffer)
558{
559 iio_buffer_get(buffer);
560 list_add(&buffer->buffer_list, &indio_dev->buffer_list);
561}
562
563static void iio_buffer_deactivate(struct iio_buffer *buffer)
564{
565 list_del_init(&buffer->buffer_list);
566 wake_up_interruptible(&buffer->pollq);
567 iio_buffer_put(buffer);
568}
569
570static void iio_buffer_deactivate_all(struct iio_dev *indio_dev)
571{
572 struct iio_buffer *buffer, *_buffer;
573
574 list_for_each_entry_safe(buffer, _buffer,
575 &indio_dev->buffer_list, buffer_list)
576 iio_buffer_deactivate(buffer);
577}
578
579static int iio_buffer_enable(struct iio_buffer *buffer,
580 struct iio_dev *indio_dev)
581{
582 if (!buffer->access->enable)
583 return 0;
584 return buffer->access->enable(buffer, indio_dev);
585}
586
587static int iio_buffer_disable(struct iio_buffer *buffer,
588 struct iio_dev *indio_dev)
589{
590 if (!buffer->access->disable)
591 return 0;
592 return buffer->access->disable(buffer, indio_dev);
593}
594
595static void iio_buffer_update_bytes_per_datum(struct iio_dev *indio_dev,
596 struct iio_buffer *buffer)
597{
598 unsigned int bytes;
599
600 if (!buffer->access->set_bytes_per_datum)
601 return;
602
603 bytes = iio_compute_scan_bytes(indio_dev, buffer->scan_mask,
604 buffer->scan_timestamp);
605
606 buffer->access->set_bytes_per_datum(buffer, bytes);
607}
608
609static int iio_buffer_request_update(struct iio_dev *indio_dev,
610 struct iio_buffer *buffer)
611{
612 int ret;
613
614 iio_buffer_update_bytes_per_datum(indio_dev, buffer);
615 if (buffer->access->request_update) {
616 ret = buffer->access->request_update(buffer);
617 if (ret) {
618 dev_dbg(&indio_dev->dev,
619 "Buffer not started: buffer parameter update failed (%d)\n",
620 ret);
621 return ret;
622 }
623 }
624
625 return 0;
626}
627
628static void iio_free_scan_mask(struct iio_dev *indio_dev,
629 const unsigned long *mask)
630{
631 /* If the mask is dynamically allocated free it, otherwise do nothing */
632 if (!indio_dev->available_scan_masks)
633 kfree(mask);
634}
635
636struct iio_device_config {
637 unsigned int mode;
638 unsigned int watermark;
639 const unsigned long *scan_mask;
640 unsigned int scan_bytes;
641 bool scan_timestamp;
642};
643
644static int iio_verify_update(struct iio_dev *indio_dev,
645 struct iio_buffer *insert_buffer, struct iio_buffer *remove_buffer,
646 struct iio_device_config *config)
647{
648 unsigned long *compound_mask;
649 const unsigned long *scan_mask;
650 bool strict_scanmask = false;
651 struct iio_buffer *buffer;
652 bool scan_timestamp;
653 unsigned int modes;
654
655 memset(config, 0, sizeof(*config));
656 config->watermark = ~0;
657
658 /*
659 * If there is just one buffer and we are removing it there is nothing
660 * to verify.
661 */
662 if (remove_buffer && !insert_buffer &&
663 list_is_singular(&indio_dev->buffer_list))
664 return 0;
665
666 modes = indio_dev->modes;
667
668 list_for_each_entry(buffer, &indio_dev->buffer_list, buffer_list) {
669 if (buffer == remove_buffer)
670 continue;
671 modes &= buffer->access->modes;
672 config->watermark = min(config->watermark, buffer->watermark);
673 }
674
675 if (insert_buffer) {
676 modes &= insert_buffer->access->modes;
677 config->watermark = min(config->watermark,
678 insert_buffer->watermark);
679 }
680
681 /* Definitely possible for devices to support both of these. */
682 if ((modes & INDIO_BUFFER_TRIGGERED) && indio_dev->trig) {
683 config->mode = INDIO_BUFFER_TRIGGERED;
684 } else if (modes & INDIO_BUFFER_HARDWARE) {
685 /*
686 * Keep things simple for now and only allow a single buffer to
687 * be connected in hardware mode.
688 */
689 if (insert_buffer && !list_empty(&indio_dev->buffer_list))
690 return -EINVAL;
691 config->mode = INDIO_BUFFER_HARDWARE;
692 strict_scanmask = true;
693 } else if (modes & INDIO_BUFFER_SOFTWARE) {
694 config->mode = INDIO_BUFFER_SOFTWARE;
695 } else {
696 /* Can only occur on first buffer */
697 if (indio_dev->modes & INDIO_BUFFER_TRIGGERED)
698 dev_dbg(&indio_dev->dev, "Buffer not started: no trigger\n");
699 return -EINVAL;
700 }
701
702 /* What scan mask do we actually have? */
703 compound_mask = kcalloc(BITS_TO_LONGS(indio_dev->masklength),
704 sizeof(long), GFP_KERNEL);
705 if (compound_mask == NULL)
706 return -ENOMEM;
707
708 scan_timestamp = false;
709
710 list_for_each_entry(buffer, &indio_dev->buffer_list, buffer_list) {
711 if (buffer == remove_buffer)
712 continue;
713 bitmap_or(compound_mask, compound_mask, buffer->scan_mask,
714 indio_dev->masklength);
715 scan_timestamp |= buffer->scan_timestamp;
716 }
717
718 if (insert_buffer) {
719 bitmap_or(compound_mask, compound_mask,
720 insert_buffer->scan_mask, indio_dev->masklength);
721 scan_timestamp |= insert_buffer->scan_timestamp;
722 }
723
724 if (indio_dev->available_scan_masks) {
725 scan_mask = iio_scan_mask_match(indio_dev->available_scan_masks,
726 indio_dev->masklength,
727 compound_mask,
728 strict_scanmask);
729 kfree(compound_mask);
730 if (scan_mask == NULL)
731 return -EINVAL;
732 } else {
733 scan_mask = compound_mask;
734 }
735
736 config->scan_bytes = iio_compute_scan_bytes(indio_dev,
737 scan_mask, scan_timestamp);
738 config->scan_mask = scan_mask;
739 config->scan_timestamp = scan_timestamp;
740
741 return 0;
742}
743
744static int iio_enable_buffers(struct iio_dev *indio_dev,
745 struct iio_device_config *config)
746{
747 struct iio_buffer *buffer;
748 int ret;
749
750 indio_dev->active_scan_mask = config->scan_mask;
751 indio_dev->scan_timestamp = config->scan_timestamp;
752 indio_dev->scan_bytes = config->scan_bytes;
753
754 iio_update_demux(indio_dev);
755
756 /* Wind up again */
757 if (indio_dev->setup_ops->preenable) {
758 ret = indio_dev->setup_ops->preenable(indio_dev);
759 if (ret) {
760 dev_dbg(&indio_dev->dev,
761 "Buffer not started: buffer preenable failed (%d)\n", ret);
762 goto err_undo_config;
763 }
764 }
765
766 if (indio_dev->info->update_scan_mode) {
767 ret = indio_dev->info
768 ->update_scan_mode(indio_dev,
769 indio_dev->active_scan_mask);
770 if (ret < 0) {
771 dev_dbg(&indio_dev->dev,
772 "Buffer not started: update scan mode failed (%d)\n",
773 ret);
774 goto err_run_postdisable;
775 }
776 }
777
778 if (indio_dev->info->hwfifo_set_watermark)
779 indio_dev->info->hwfifo_set_watermark(indio_dev,
780 config->watermark);
781
782 list_for_each_entry(buffer, &indio_dev->buffer_list, buffer_list) {
783 ret = iio_buffer_enable(buffer, indio_dev);
784 if (ret)
785 goto err_disable_buffers;
786 }
787
788 indio_dev->currentmode = config->mode;
789
790 if (indio_dev->setup_ops->postenable) {
791 ret = indio_dev->setup_ops->postenable(indio_dev);
792 if (ret) {
793 dev_dbg(&indio_dev->dev,
794 "Buffer not started: postenable failed (%d)\n", ret);
795 goto err_disable_buffers;
796 }
797 }
798
799 return 0;
800
801err_disable_buffers:
802 list_for_each_entry_continue_reverse(buffer, &indio_dev->buffer_list,
803 buffer_list)
804 iio_buffer_disable(buffer, indio_dev);
805err_run_postdisable:
806 indio_dev->currentmode = INDIO_DIRECT_MODE;
807 if (indio_dev->setup_ops->postdisable)
808 indio_dev->setup_ops->postdisable(indio_dev);
809err_undo_config:
810 indio_dev->active_scan_mask = NULL;
811
812 return ret;
813}
814
815static int iio_disable_buffers(struct iio_dev *indio_dev)
816{
817 struct iio_buffer *buffer;
818 int ret = 0;
819 int ret2;
820
821 /* Wind down existing buffers - iff there are any */
822 if (list_empty(&indio_dev->buffer_list))
823 return 0;
824
825 /*
826 * If things go wrong at some step in disable we still need to continue
827 * to perform the other steps, otherwise we leave the device in a
828 * inconsistent state. We return the error code for the first error we
829 * encountered.
830 */
831
832 if (indio_dev->setup_ops->predisable) {
833 ret2 = indio_dev->setup_ops->predisable(indio_dev);
834 if (ret2 && !ret)
835 ret = ret2;
836 }
837
838 list_for_each_entry(buffer, &indio_dev->buffer_list, buffer_list) {
839 ret2 = iio_buffer_disable(buffer, indio_dev);
840 if (ret2 && !ret)
841 ret = ret2;
842 }
843
844 indio_dev->currentmode = INDIO_DIRECT_MODE;
845
846 if (indio_dev->setup_ops->postdisable) {
847 ret2 = indio_dev->setup_ops->postdisable(indio_dev);
848 if (ret2 && !ret)
849 ret = ret2;
850 }
851
852 iio_free_scan_mask(indio_dev, indio_dev->active_scan_mask);
853 indio_dev->active_scan_mask = NULL;
854
855 return ret;
856}
857
858static int __iio_update_buffers(struct iio_dev *indio_dev,
859 struct iio_buffer *insert_buffer,
860 struct iio_buffer *remove_buffer)
861{
862 struct iio_device_config new_config;
863 int ret;
864
865 ret = iio_verify_update(indio_dev, insert_buffer, remove_buffer,
866 &new_config);
867 if (ret)
868 return ret;
869
870 if (insert_buffer) {
871 ret = iio_buffer_request_update(indio_dev, insert_buffer);
872 if (ret)
873 goto err_free_config;
874 }
875
876 ret = iio_disable_buffers(indio_dev);
877 if (ret)
878 goto err_deactivate_all;
879
880 if (remove_buffer)
881 iio_buffer_deactivate(remove_buffer);
882 if (insert_buffer)
883 iio_buffer_activate(indio_dev, insert_buffer);
884
885 /* If no buffers in list, we are done */
886 if (list_empty(&indio_dev->buffer_list))
887 return 0;
888
889 ret = iio_enable_buffers(indio_dev, &new_config);
890 if (ret)
891 goto err_deactivate_all;
892
893 return 0;
894
895err_deactivate_all:
896 /*
897 * We've already verified that the config is valid earlier. If things go
898 * wrong in either enable or disable the most likely reason is an IO
899 * error from the device. In this case there is no good recovery
900 * strategy. Just make sure to disable everything and leave the device
901 * in a sane state. With a bit of luck the device might come back to
902 * life again later and userspace can try again.
903 */
904 iio_buffer_deactivate_all(indio_dev);
905
906err_free_config:
907 iio_free_scan_mask(indio_dev, new_config.scan_mask);
908 return ret;
909}
910
911int iio_update_buffers(struct iio_dev *indio_dev,
912 struct iio_buffer *insert_buffer,
913 struct iio_buffer *remove_buffer)
914{
915 int ret;
916
917 if (insert_buffer == remove_buffer)
918 return 0;
919
920 mutex_lock(&indio_dev->info_exist_lock);
921 mutex_lock(&indio_dev->mlock);
922
923 if (insert_buffer && iio_buffer_is_active(insert_buffer))
924 insert_buffer = NULL;
925
926 if (remove_buffer && !iio_buffer_is_active(remove_buffer))
927 remove_buffer = NULL;
928
929 if (!insert_buffer && !remove_buffer) {
930 ret = 0;
931 goto out_unlock;
932 }
933
934 if (indio_dev->info == NULL) {
935 ret = -ENODEV;
936 goto out_unlock;
937 }
938
939 ret = __iio_update_buffers(indio_dev, insert_buffer, remove_buffer);
940
941out_unlock:
942 mutex_unlock(&indio_dev->mlock);
943 mutex_unlock(&indio_dev->info_exist_lock);
944
945 return ret;
946}
947EXPORT_SYMBOL_GPL(iio_update_buffers);
948
949void iio_disable_all_buffers(struct iio_dev *indio_dev)
950{
951 iio_disable_buffers(indio_dev);
952 iio_buffer_deactivate_all(indio_dev);
953}
954
955static ssize_t iio_buffer_store_enable(struct device *dev,
956 struct device_attribute *attr,
957 const char *buf,
958 size_t len)
959{
960 int ret;
961 bool requested_state;
962 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
963 bool inlist;
964
965 ret = strtobool(buf, &requested_state);
966 if (ret < 0)
967 return ret;
968
969 mutex_lock(&indio_dev->mlock);
970
971 /* Find out if it is in the list */
972 inlist = iio_buffer_is_active(indio_dev->buffer);
973 /* Already in desired state */
974 if (inlist == requested_state)
975 goto done;
976
977 if (requested_state)
978 ret = __iio_update_buffers(indio_dev,
979 indio_dev->buffer, NULL);
980 else
981 ret = __iio_update_buffers(indio_dev,
982 NULL, indio_dev->buffer);
983
984done:
985 mutex_unlock(&indio_dev->mlock);
986 return (ret < 0) ? ret : len;
987}
988
989static const char * const iio_scan_elements_group_name = "scan_elements";
990
991static ssize_t iio_buffer_show_watermark(struct device *dev,
992 struct device_attribute *attr,
993 char *buf)
994{
995 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
996 struct iio_buffer *buffer = indio_dev->buffer;
997
998 return sprintf(buf, "%u\n", buffer->watermark);
999}
1000
1001static ssize_t iio_buffer_store_watermark(struct device *dev,
1002 struct device_attribute *attr,
1003 const char *buf,
1004 size_t len)
1005{
1006 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
1007 struct iio_buffer *buffer = indio_dev->buffer;
1008 unsigned int val;
1009 int ret;
1010
1011 ret = kstrtouint(buf, 10, &val);
1012 if (ret)
1013 return ret;
1014 if (!val)
1015 return -EINVAL;
1016
1017 mutex_lock(&indio_dev->mlock);
1018
1019 if (val > buffer->length) {
1020 ret = -EINVAL;
1021 goto out;
1022 }
1023
1024 if (iio_buffer_is_active(indio_dev->buffer)) {
1025 ret = -EBUSY;
1026 goto out;
1027 }
1028
1029 buffer->watermark = val;
1030out:
1031 mutex_unlock(&indio_dev->mlock);
1032
1033 return ret ? ret : len;
1034}
1035
1036static DEVICE_ATTR(length, S_IRUGO | S_IWUSR, iio_buffer_read_length,
1037 iio_buffer_write_length);
1038static struct device_attribute dev_attr_length_ro = __ATTR(length,
1039 S_IRUGO, iio_buffer_read_length, NULL);
1040static DEVICE_ATTR(enable, S_IRUGO | S_IWUSR,
1041 iio_buffer_show_enable, iio_buffer_store_enable);
1042static DEVICE_ATTR(watermark, S_IRUGO | S_IWUSR,
1043 iio_buffer_show_watermark, iio_buffer_store_watermark);
1044static struct device_attribute dev_attr_watermark_ro = __ATTR(watermark,
1045 S_IRUGO, iio_buffer_show_watermark, NULL);
1046
1047static struct attribute *iio_buffer_attrs[] = {
1048 &dev_attr_length.attr,
1049 &dev_attr_enable.attr,
1050 &dev_attr_watermark.attr,
1051};
1052
1053int iio_buffer_alloc_sysfs_and_mask(struct iio_dev *indio_dev)
1054{
1055 struct iio_dev_attr *p;
1056 struct attribute **attr;
1057 struct iio_buffer *buffer = indio_dev->buffer;
1058 int ret, i, attrn, attrcount, attrcount_orig = 0;
1059 const struct iio_chan_spec *channels;
1060
1061 channels = indio_dev->channels;
1062 if (channels) {
1063 int ml = indio_dev->masklength;
1064
1065 for (i = 0; i < indio_dev->num_channels; i++)
1066 ml = max(ml, channels[i].scan_index + 1);
1067 indio_dev->masklength = ml;
1068 }
1069
1070 if (!buffer)
1071 return 0;
1072
1073 attrcount = 0;
1074 if (buffer->attrs) {
1075 while (buffer->attrs[attrcount] != NULL)
1076 attrcount++;
1077 }
1078
1079 attr = kcalloc(attrcount + ARRAY_SIZE(iio_buffer_attrs) + 1,
1080 sizeof(struct attribute *), GFP_KERNEL);
1081 if (!attr)
1082 return -ENOMEM;
1083
1084 memcpy(attr, iio_buffer_attrs, sizeof(iio_buffer_attrs));
1085 if (!buffer->access->set_length)
1086 attr[0] = &dev_attr_length_ro.attr;
1087
1088 if (buffer->access->flags & INDIO_BUFFER_FLAG_FIXED_WATERMARK)
1089 attr[2] = &dev_attr_watermark_ro.attr;
1090
1091 if (buffer->attrs)
1092 memcpy(&attr[ARRAY_SIZE(iio_buffer_attrs)], buffer->attrs,
1093 sizeof(struct attribute *) * attrcount);
1094
1095 attr[attrcount + ARRAY_SIZE(iio_buffer_attrs)] = NULL;
1096
1097 buffer->buffer_group.name = "buffer";
1098 buffer->buffer_group.attrs = attr;
1099
1100 indio_dev->groups[indio_dev->groupcounter++] = &buffer->buffer_group;
1101
1102 if (buffer->scan_el_attrs != NULL) {
1103 attr = buffer->scan_el_attrs->attrs;
1104 while (*attr++ != NULL)
1105 attrcount_orig++;
1106 }
1107 attrcount = attrcount_orig;
1108 INIT_LIST_HEAD(&buffer->scan_el_dev_attr_list);
1109 channels = indio_dev->channels;
1110 if (channels) {
1111 /* new magic */
1112 for (i = 0; i < indio_dev->num_channels; i++) {
1113 if (channels[i].scan_index < 0)
1114 continue;
1115
1116 ret = iio_buffer_add_channel_sysfs(indio_dev,
1117 &channels[i]);
1118 if (ret < 0)
1119 goto error_cleanup_dynamic;
1120 attrcount += ret;
1121 if (channels[i].type == IIO_TIMESTAMP)
1122 indio_dev->scan_index_timestamp =
1123 channels[i].scan_index;
1124 }
1125 if (indio_dev->masklength && buffer->scan_mask == NULL) {
1126 buffer->scan_mask = kcalloc(BITS_TO_LONGS(indio_dev->masklength),
1127 sizeof(*buffer->scan_mask),
1128 GFP_KERNEL);
1129 if (buffer->scan_mask == NULL) {
1130 ret = -ENOMEM;
1131 goto error_cleanup_dynamic;
1132 }
1133 }
1134 }
1135
1136 buffer->scan_el_group.name = iio_scan_elements_group_name;
1137
1138 buffer->scan_el_group.attrs = kcalloc(attrcount + 1,
1139 sizeof(buffer->scan_el_group.attrs[0]),
1140 GFP_KERNEL);
1141 if (buffer->scan_el_group.attrs == NULL) {
1142 ret = -ENOMEM;
1143 goto error_free_scan_mask;
1144 }
1145 if (buffer->scan_el_attrs)
1146 memcpy(buffer->scan_el_group.attrs, buffer->scan_el_attrs,
1147 sizeof(buffer->scan_el_group.attrs[0])*attrcount_orig);
1148 attrn = attrcount_orig;
1149
1150 list_for_each_entry(p, &buffer->scan_el_dev_attr_list, l)
1151 buffer->scan_el_group.attrs[attrn++] = &p->dev_attr.attr;
1152 indio_dev->groups[indio_dev->groupcounter++] = &buffer->scan_el_group;
1153
1154 return 0;
1155
1156error_free_scan_mask:
1157 kfree(buffer->scan_mask);
1158error_cleanup_dynamic:
1159 iio_free_chan_devattr_list(&buffer->scan_el_dev_attr_list);
1160 kfree(indio_dev->buffer->buffer_group.attrs);
1161
1162 return ret;
1163}
1164
1165void iio_buffer_free_sysfs_and_mask(struct iio_dev *indio_dev)
1166{
1167 if (!indio_dev->buffer)
1168 return;
1169
1170 kfree(indio_dev->buffer->scan_mask);
1171 kfree(indio_dev->buffer->buffer_group.attrs);
1172 kfree(indio_dev->buffer->scan_el_group.attrs);
1173 iio_free_chan_devattr_list(&indio_dev->buffer->scan_el_dev_attr_list);
1174}
1175
1176/**
1177 * iio_validate_scan_mask_onehot() - Validates that exactly one channel is selected
1178 * @indio_dev: the iio device
1179 * @mask: scan mask to be checked
1180 *
1181 * Return true if exactly one bit is set in the scan mask, false otherwise. It
1182 * can be used for devices where only one channel can be active for sampling at
1183 * a time.
1184 */
1185bool iio_validate_scan_mask_onehot(struct iio_dev *indio_dev,
1186 const unsigned long *mask)
1187{
1188 return bitmap_weight(mask, indio_dev->masklength) == 1;
1189}
1190EXPORT_SYMBOL_GPL(iio_validate_scan_mask_onehot);
1191
1192int iio_scan_mask_query(struct iio_dev *indio_dev,
1193 struct iio_buffer *buffer, int bit)
1194{
1195 if (bit > indio_dev->masklength)
1196 return -EINVAL;
1197
1198 if (!buffer->scan_mask)
1199 return 0;
1200
1201 /* Ensure return value is 0 or 1. */
1202 return !!test_bit(bit, buffer->scan_mask);
1203};
1204EXPORT_SYMBOL_GPL(iio_scan_mask_query);
1205
1206/**
1207 * struct iio_demux_table - table describing demux memcpy ops
1208 * @from: index to copy from
1209 * @to: index to copy to
1210 * @length: how many bytes to copy
1211 * @l: list head used for management
1212 */
1213struct iio_demux_table {
1214 unsigned from;
1215 unsigned to;
1216 unsigned length;
1217 struct list_head l;
1218};
1219
1220static const void *iio_demux(struct iio_buffer *buffer,
1221 const void *datain)
1222{
1223 struct iio_demux_table *t;
1224
1225 if (list_empty(&buffer->demux_list))
1226 return datain;
1227 list_for_each_entry(t, &buffer->demux_list, l)
1228 memcpy(buffer->demux_bounce + t->to,
1229 datain + t->from, t->length);
1230
1231 return buffer->demux_bounce;
1232}
1233
1234static int iio_push_to_buffer(struct iio_buffer *buffer, const void *data)
1235{
1236 const void *dataout = iio_demux(buffer, data);
1237 int ret;
1238
1239 ret = buffer->access->store_to(buffer, dataout);
1240 if (ret)
1241 return ret;
1242
1243 /*
1244 * We can't just test for watermark to decide if we wake the poll queue
1245 * because read may request less samples than the watermark.
1246 */
1247 wake_up_interruptible_poll(&buffer->pollq, POLLIN | POLLRDNORM);
1248 return 0;
1249}
1250
1251static void iio_buffer_demux_free(struct iio_buffer *buffer)
1252{
1253 struct iio_demux_table *p, *q;
1254 list_for_each_entry_safe(p, q, &buffer->demux_list, l) {
1255 list_del(&p->l);
1256 kfree(p);
1257 }
1258}
1259
1260
1261int iio_push_to_buffers(struct iio_dev *indio_dev, const void *data)
1262{
1263 int ret;
1264 struct iio_buffer *buf;
1265
1266 list_for_each_entry(buf, &indio_dev->buffer_list, buffer_list) {
1267 ret = iio_push_to_buffer(buf, data);
1268 if (ret < 0)
1269 return ret;
1270 }
1271
1272 return 0;
1273}
1274EXPORT_SYMBOL_GPL(iio_push_to_buffers);
1275
1276static int iio_buffer_add_demux(struct iio_buffer *buffer,
1277 struct iio_demux_table **p, unsigned int in_loc, unsigned int out_loc,
1278 unsigned int length)
1279{
1280
1281 if (*p && (*p)->from + (*p)->length == in_loc &&
1282 (*p)->to + (*p)->length == out_loc) {
1283 (*p)->length += length;
1284 } else {
1285 *p = kmalloc(sizeof(**p), GFP_KERNEL);
1286 if (*p == NULL)
1287 return -ENOMEM;
1288 (*p)->from = in_loc;
1289 (*p)->to = out_loc;
1290 (*p)->length = length;
1291 list_add_tail(&(*p)->l, &buffer->demux_list);
1292 }
1293
1294 return 0;
1295}
1296
1297static int iio_buffer_update_demux(struct iio_dev *indio_dev,
1298 struct iio_buffer *buffer)
1299{
1300 int ret, in_ind = -1, out_ind, length;
1301 unsigned in_loc = 0, out_loc = 0;
1302 struct iio_demux_table *p = NULL;
1303
1304 /* Clear out any old demux */
1305 iio_buffer_demux_free(buffer);
1306 kfree(buffer->demux_bounce);
1307 buffer->demux_bounce = NULL;
1308
1309 /* First work out which scan mode we will actually have */
1310 if (bitmap_equal(indio_dev->active_scan_mask,
1311 buffer->scan_mask,
1312 indio_dev->masklength))
1313 return 0;
1314
1315 /* Now we have the two masks, work from least sig and build up sizes */
1316 for_each_set_bit(out_ind,
1317 buffer->scan_mask,
1318 indio_dev->masklength) {
1319 in_ind = find_next_bit(indio_dev->active_scan_mask,
1320 indio_dev->masklength,
1321 in_ind + 1);
1322 while (in_ind != out_ind) {
1323 in_ind = find_next_bit(indio_dev->active_scan_mask,
1324 indio_dev->masklength,
1325 in_ind + 1);
1326 length = iio_storage_bytes_for_si(indio_dev, in_ind);
1327 /* Make sure we are aligned */
1328 in_loc = roundup(in_loc, length) + length;
1329 }
1330 length = iio_storage_bytes_for_si(indio_dev, in_ind);
1331 out_loc = roundup(out_loc, length);
1332 in_loc = roundup(in_loc, length);
1333 ret = iio_buffer_add_demux(buffer, &p, in_loc, out_loc, length);
1334 if (ret)
1335 goto error_clear_mux_table;
1336 out_loc += length;
1337 in_loc += length;
1338 }
1339 /* Relies on scan_timestamp being last */
1340 if (buffer->scan_timestamp) {
1341 length = iio_storage_bytes_for_timestamp(indio_dev);
1342 out_loc = roundup(out_loc, length);
1343 in_loc = roundup(in_loc, length);
1344 ret = iio_buffer_add_demux(buffer, &p, in_loc, out_loc, length);
1345 if (ret)
1346 goto error_clear_mux_table;
1347 out_loc += length;
1348 in_loc += length;
1349 }
1350 buffer->demux_bounce = kzalloc(out_loc, GFP_KERNEL);
1351 if (buffer->demux_bounce == NULL) {
1352 ret = -ENOMEM;
1353 goto error_clear_mux_table;
1354 }
1355 return 0;
1356
1357error_clear_mux_table:
1358 iio_buffer_demux_free(buffer);
1359
1360 return ret;
1361}
1362
1363int iio_update_demux(struct iio_dev *indio_dev)
1364{
1365 struct iio_buffer *buffer;
1366 int ret;
1367
1368 list_for_each_entry(buffer, &indio_dev->buffer_list, buffer_list) {
1369 ret = iio_buffer_update_demux(indio_dev, buffer);
1370 if (ret < 0)
1371 goto error_clear_mux_table;
1372 }
1373 return 0;
1374
1375error_clear_mux_table:
1376 list_for_each_entry(buffer, &indio_dev->buffer_list, buffer_list)
1377 iio_buffer_demux_free(buffer);
1378
1379 return ret;
1380}
1381EXPORT_SYMBOL_GPL(iio_update_demux);
1382
1383/**
1384 * iio_buffer_release() - Free a buffer's resources
1385 * @ref: Pointer to the kref embedded in the iio_buffer struct
1386 *
1387 * This function is called when the last reference to the buffer has been
1388 * dropped. It will typically free all resources allocated by the buffer. Do not
1389 * call this function manually, always use iio_buffer_put() when done using a
1390 * buffer.
1391 */
1392static void iio_buffer_release(struct kref *ref)
1393{
1394 struct iio_buffer *buffer = container_of(ref, struct iio_buffer, ref);
1395
1396 buffer->access->release(buffer);
1397}
1398
1399/**
1400 * iio_buffer_get() - Grab a reference to the buffer
1401 * @buffer: The buffer to grab a reference for, may be NULL
1402 *
1403 * Returns the pointer to the buffer that was passed into the function.
1404 */
1405struct iio_buffer *iio_buffer_get(struct iio_buffer *buffer)
1406{
1407 if (buffer)
1408 kref_get(&buffer->ref);
1409
1410 return buffer;
1411}
1412EXPORT_SYMBOL_GPL(iio_buffer_get);
1413
1414/**
1415 * iio_buffer_put() - Release the reference to the buffer
1416 * @buffer: The buffer to release the reference for, may be NULL
1417 */
1418void iio_buffer_put(struct iio_buffer *buffer)
1419{
1420 if (buffer)
1421 kref_put(&buffer->ref, iio_buffer_release);
1422}
1423EXPORT_SYMBOL_GPL(iio_buffer_put);