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