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1/* The industrial I/O core
2 *
3 * Copyright (c) 2008 Jonathan Cameron
4 *
5 * This program is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 as published by
7 * the Free Software Foundation.
8 *
9 * Handling of buffer allocation / resizing.
10 *
11 *
12 * Things to look at here.
13 * - Better memory allocation techniques?
14 * - Alternative access techniques?
15 */
16#include <linux/kernel.h>
17#include <linux/export.h>
18#include <linux/device.h>
19#include <linux/fs.h>
20#include <linux/cdev.h>
21#include <linux/slab.h>
22#include <linux/poll.h>
23#include <linux/sched.h>
24
25#include <linux/iio/iio.h>
26#include "iio_core.h"
27#include <linux/iio/sysfs.h>
28#include <linux/iio/buffer.h>
29
30static const char * const iio_endian_prefix[] = {
31 [IIO_BE] = "be",
32 [IIO_LE] = "le",
33};
34
35static bool iio_buffer_is_active(struct iio_buffer *buf)
36{
37 return !list_empty(&buf->buffer_list);
38}
39
40static size_t iio_buffer_data_available(struct iio_buffer *buf)
41{
42 return buf->access->data_available(buf);
43}
44
45static int iio_buffer_flush_hwfifo(struct iio_dev *indio_dev,
46 struct iio_buffer *buf, size_t required)
47{
48 if (!indio_dev->info->hwfifo_flush_to_buffer)
49 return -ENODEV;
50
51 return indio_dev->info->hwfifo_flush_to_buffer(indio_dev, required);
52}
53
54static bool iio_buffer_ready(struct iio_dev *indio_dev, struct iio_buffer *buf,
55 size_t to_wait, int to_flush)
56{
57 size_t avail;
58 int flushed = 0;
59
60 /* wakeup if the device was unregistered */
61 if (!indio_dev->info)
62 return true;
63
64 /* drain the buffer if it was disabled */
65 if (!iio_buffer_is_active(buf)) {
66 to_wait = min_t(size_t, to_wait, 1);
67 to_flush = 0;
68 }
69
70 avail = iio_buffer_data_available(buf);
71
72 if (avail >= to_wait) {
73 /* force a flush for non-blocking reads */
74 if (!to_wait && avail < to_flush)
75 iio_buffer_flush_hwfifo(indio_dev, buf,
76 to_flush - avail);
77 return true;
78 }
79
80 if (to_flush)
81 flushed = iio_buffer_flush_hwfifo(indio_dev, buf,
82 to_wait - avail);
83 if (flushed <= 0)
84 return false;
85
86 if (avail + flushed >= to_wait)
87 return true;
88
89 return false;
90}
91
92/**
93 * iio_buffer_read_first_n_outer() - chrdev read for buffer access
94 * @filp: File structure pointer for the char device
95 * @buf: Destination buffer for iio buffer read
96 * @n: First n bytes to read
97 * @f_ps: Long offset provided by the user as a seek position
98 *
99 * This function relies on all buffer implementations having an
100 * iio_buffer as their first element.
101 *
102 * Return: negative values corresponding to error codes or ret != 0
103 * for ending the reading activity
104 **/
105ssize_t iio_buffer_read_first_n_outer(struct file *filp, char __user *buf,
106 size_t n, loff_t *f_ps)
107{
108 struct iio_dev *indio_dev = filp->private_data;
109 struct iio_buffer *rb = indio_dev->buffer;
110 size_t datum_size;
111 size_t to_wait;
112 int ret;
113
114 if (!indio_dev->info)
115 return -ENODEV;
116
117 if (!rb || !rb->access->read_first_n)
118 return -EINVAL;
119
120 datum_size = rb->bytes_per_datum;
121
122 /*
123 * If datum_size is 0 there will never be anything to read from the
124 * buffer, so signal end of file now.
125 */
126 if (!datum_size)
127 return 0;
128
129 if (filp->f_flags & O_NONBLOCK)
130 to_wait = 0;
131 else
132 to_wait = min_t(size_t, n / datum_size, rb->watermark);
133
134 do {
135 ret = wait_event_interruptible(rb->pollq,
136 iio_buffer_ready(indio_dev, rb, to_wait, n / datum_size));
137 if (ret)
138 return ret;
139
140 if (!indio_dev->info)
141 return -ENODEV;
142
143 ret = rb->access->read_first_n(rb, n, buf);
144 if (ret == 0 && (filp->f_flags & O_NONBLOCK))
145 ret = -EAGAIN;
146 } while (ret == 0);
147
148 return ret;
149}
150
151/**
152 * iio_buffer_poll() - poll the buffer to find out if it has data
153 * @filp: File structure pointer for device access
154 * @wait: Poll table structure pointer for which the driver adds
155 * a wait queue
156 *
157 * Return: (POLLIN | POLLRDNORM) if data is available for reading
158 * or 0 for other cases
159 */
160unsigned int iio_buffer_poll(struct file *filp,
161 struct poll_table_struct *wait)
162{
163 struct iio_dev *indio_dev = filp->private_data;
164 struct iio_buffer *rb = indio_dev->buffer;
165
166 if (!indio_dev->info)
167 return 0;
168
169 poll_wait(filp, &rb->pollq, wait);
170 if (iio_buffer_ready(indio_dev, rb, rb->watermark, 0))
171 return POLLIN | POLLRDNORM;
172 return 0;
173}
174
175/**
176 * iio_buffer_wakeup_poll - Wakes up the buffer waitqueue
177 * @indio_dev: The IIO device
178 *
179 * Wakes up the event waitqueue used for poll(). Should usually
180 * be called when the device is unregistered.
181 */
182void iio_buffer_wakeup_poll(struct iio_dev *indio_dev)
183{
184 if (!indio_dev->buffer)
185 return;
186
187 wake_up(&indio_dev->buffer->pollq);
188}
189
190void iio_buffer_init(struct iio_buffer *buffer)
191{
192 INIT_LIST_HEAD(&buffer->demux_list);
193 INIT_LIST_HEAD(&buffer->buffer_list);
194 init_waitqueue_head(&buffer->pollq);
195 kref_init(&buffer->ref);
196 if (!buffer->watermark)
197 buffer->watermark = 1;
198}
199EXPORT_SYMBOL(iio_buffer_init);
200
201static ssize_t iio_show_scan_index(struct device *dev,
202 struct device_attribute *attr,
203 char *buf)
204{
205 return sprintf(buf, "%u\n", to_iio_dev_attr(attr)->c->scan_index);
206}
207
208static ssize_t iio_show_fixed_type(struct device *dev,
209 struct device_attribute *attr,
210 char *buf)
211{
212 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
213 u8 type = this_attr->c->scan_type.endianness;
214
215 if (type == IIO_CPU) {
216#ifdef __LITTLE_ENDIAN
217 type = IIO_LE;
218#else
219 type = IIO_BE;
220#endif
221 }
222 if (this_attr->c->scan_type.repeat > 1)
223 return sprintf(buf, "%s:%c%d/%dX%d>>%u\n",
224 iio_endian_prefix[type],
225 this_attr->c->scan_type.sign,
226 this_attr->c->scan_type.realbits,
227 this_attr->c->scan_type.storagebits,
228 this_attr->c->scan_type.repeat,
229 this_attr->c->scan_type.shift);
230 else
231 return sprintf(buf, "%s:%c%d/%d>>%u\n",
232 iio_endian_prefix[type],
233 this_attr->c->scan_type.sign,
234 this_attr->c->scan_type.realbits,
235 this_attr->c->scan_type.storagebits,
236 this_attr->c->scan_type.shift);
237}
238
239static ssize_t iio_scan_el_show(struct device *dev,
240 struct device_attribute *attr,
241 char *buf)
242{
243 int ret;
244 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
245
246 /* Ensure ret is 0 or 1. */
247 ret = !!test_bit(to_iio_dev_attr(attr)->address,
248 indio_dev->buffer->scan_mask);
249
250 return sprintf(buf, "%d\n", ret);
251}
252
253/* Note NULL used as error indicator as it doesn't make sense. */
254static const unsigned long *iio_scan_mask_match(const unsigned long *av_masks,
255 unsigned int masklength,
256 const unsigned long *mask,
257 bool strict)
258{
259 if (bitmap_empty(mask, masklength))
260 return NULL;
261 while (*av_masks) {
262 if (strict) {
263 if (bitmap_equal(mask, av_masks, masklength))
264 return av_masks;
265 } else {
266 if (bitmap_subset(mask, av_masks, masklength))
267 return av_masks;
268 }
269 av_masks += BITS_TO_LONGS(masklength);
270 }
271 return NULL;
272}
273
274static bool iio_validate_scan_mask(struct iio_dev *indio_dev,
275 const unsigned long *mask)
276{
277 if (!indio_dev->setup_ops->validate_scan_mask)
278 return true;
279
280 return indio_dev->setup_ops->validate_scan_mask(indio_dev, mask);
281}
282
283/**
284 * iio_scan_mask_set() - set particular bit in the scan mask
285 * @indio_dev: the iio device
286 * @buffer: the buffer whose scan mask we are interested in
287 * @bit: the bit to be set.
288 *
289 * Note that at this point we have no way of knowing what other
290 * buffers might request, hence this code only verifies that the
291 * individual buffers request is plausible.
292 */
293static int iio_scan_mask_set(struct iio_dev *indio_dev,
294 struct iio_buffer *buffer, int bit)
295{
296 const unsigned long *mask;
297 unsigned long *trialmask;
298
299 trialmask = kmalloc(sizeof(*trialmask)*
300 BITS_TO_LONGS(indio_dev->masklength),
301 GFP_KERNEL);
302
303 if (trialmask == NULL)
304 return -ENOMEM;
305 if (!indio_dev->masklength) {
306 WARN(1, "Trying to set scanmask prior to registering buffer\n");
307 goto err_invalid_mask;
308 }
309 bitmap_copy(trialmask, buffer->scan_mask, indio_dev->masklength);
310 set_bit(bit, trialmask);
311
312 if (!iio_validate_scan_mask(indio_dev, trialmask))
313 goto err_invalid_mask;
314
315 if (indio_dev->available_scan_masks) {
316 mask = iio_scan_mask_match(indio_dev->available_scan_masks,
317 indio_dev->masklength,
318 trialmask, false);
319 if (!mask)
320 goto err_invalid_mask;
321 }
322 bitmap_copy(buffer->scan_mask, trialmask, indio_dev->masklength);
323
324 kfree(trialmask);
325
326 return 0;
327
328err_invalid_mask:
329 kfree(trialmask);
330 return -EINVAL;
331}
332
333static int iio_scan_mask_clear(struct iio_buffer *buffer, int bit)
334{
335 clear_bit(bit, buffer->scan_mask);
336 return 0;
337}
338
339static ssize_t iio_scan_el_store(struct device *dev,
340 struct device_attribute *attr,
341 const char *buf,
342 size_t len)
343{
344 int ret;
345 bool state;
346 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
347 struct iio_buffer *buffer = indio_dev->buffer;
348 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
349
350 ret = strtobool(buf, &state);
351 if (ret < 0)
352 return ret;
353 mutex_lock(&indio_dev->mlock);
354 if (iio_buffer_is_active(indio_dev->buffer)) {
355 ret = -EBUSY;
356 goto error_ret;
357 }
358 ret = iio_scan_mask_query(indio_dev, buffer, this_attr->address);
359 if (ret < 0)
360 goto error_ret;
361 if (!state && ret) {
362 ret = iio_scan_mask_clear(buffer, this_attr->address);
363 if (ret)
364 goto error_ret;
365 } else if (state && !ret) {
366 ret = iio_scan_mask_set(indio_dev, buffer, this_attr->address);
367 if (ret)
368 goto error_ret;
369 }
370
371error_ret:
372 mutex_unlock(&indio_dev->mlock);
373
374 return ret < 0 ? ret : len;
375
376}
377
378static ssize_t iio_scan_el_ts_show(struct device *dev,
379 struct device_attribute *attr,
380 char *buf)
381{
382 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
383 return sprintf(buf, "%d\n", indio_dev->buffer->scan_timestamp);
384}
385
386static ssize_t iio_scan_el_ts_store(struct device *dev,
387 struct device_attribute *attr,
388 const char *buf,
389 size_t len)
390{
391 int ret;
392 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
393 bool state;
394
395 ret = strtobool(buf, &state);
396 if (ret < 0)
397 return ret;
398
399 mutex_lock(&indio_dev->mlock);
400 if (iio_buffer_is_active(indio_dev->buffer)) {
401 ret = -EBUSY;
402 goto error_ret;
403 }
404 indio_dev->buffer->scan_timestamp = state;
405error_ret:
406 mutex_unlock(&indio_dev->mlock);
407
408 return ret ? ret : len;
409}
410
411static int iio_buffer_add_channel_sysfs(struct iio_dev *indio_dev,
412 const struct iio_chan_spec *chan)
413{
414 int ret, attrcount = 0;
415 struct iio_buffer *buffer = indio_dev->buffer;
416
417 ret = __iio_add_chan_devattr("index",
418 chan,
419 &iio_show_scan_index,
420 NULL,
421 0,
422 IIO_SEPARATE,
423 &indio_dev->dev,
424 &buffer->scan_el_dev_attr_list);
425 if (ret)
426 return ret;
427 attrcount++;
428 ret = __iio_add_chan_devattr("type",
429 chan,
430 &iio_show_fixed_type,
431 NULL,
432 0,
433 0,
434 &indio_dev->dev,
435 &buffer->scan_el_dev_attr_list);
436 if (ret)
437 return ret;
438 attrcount++;
439 if (chan->type != IIO_TIMESTAMP)
440 ret = __iio_add_chan_devattr("en",
441 chan,
442 &iio_scan_el_show,
443 &iio_scan_el_store,
444 chan->scan_index,
445 0,
446 &indio_dev->dev,
447 &buffer->scan_el_dev_attr_list);
448 else
449 ret = __iio_add_chan_devattr("en",
450 chan,
451 &iio_scan_el_ts_show,
452 &iio_scan_el_ts_store,
453 chan->scan_index,
454 0,
455 &indio_dev->dev,
456 &buffer->scan_el_dev_attr_list);
457 if (ret)
458 return ret;
459 attrcount++;
460 ret = attrcount;
461 return ret;
462}
463
464static ssize_t iio_buffer_read_length(struct device *dev,
465 struct device_attribute *attr,
466 char *buf)
467{
468 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
469 struct iio_buffer *buffer = indio_dev->buffer;
470
471 return sprintf(buf, "%d\n", buffer->length);
472}
473
474static ssize_t iio_buffer_write_length(struct device *dev,
475 struct device_attribute *attr,
476 const char *buf, size_t len)
477{
478 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
479 struct iio_buffer *buffer = indio_dev->buffer;
480 unsigned int val;
481 int ret;
482
483 ret = kstrtouint(buf, 10, &val);
484 if (ret)
485 return ret;
486
487 if (val == buffer->length)
488 return len;
489
490 mutex_lock(&indio_dev->mlock);
491 if (iio_buffer_is_active(indio_dev->buffer)) {
492 ret = -EBUSY;
493 } else {
494 buffer->access->set_length(buffer, val);
495 ret = 0;
496 }
497 if (ret)
498 goto out;
499 if (buffer->length && buffer->length < buffer->watermark)
500 buffer->watermark = buffer->length;
501out:
502 mutex_unlock(&indio_dev->mlock);
503
504 return ret ? ret : len;
505}
506
507static ssize_t iio_buffer_show_enable(struct device *dev,
508 struct device_attribute *attr,
509 char *buf)
510{
511 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
512 return sprintf(buf, "%d\n", iio_buffer_is_active(indio_dev->buffer));
513}
514
515static unsigned int iio_storage_bytes_for_si(struct iio_dev *indio_dev,
516 unsigned int scan_index)
517{
518 const struct iio_chan_spec *ch;
519 unsigned int bytes;
520
521 ch = iio_find_channel_from_si(indio_dev, scan_index);
522 bytes = ch->scan_type.storagebits / 8;
523 if (ch->scan_type.repeat > 1)
524 bytes *= ch->scan_type.repeat;
525 return bytes;
526}
527
528static unsigned int iio_storage_bytes_for_timestamp(struct iio_dev *indio_dev)
529{
530 return iio_storage_bytes_for_si(indio_dev,
531 indio_dev->scan_index_timestamp);
532}
533
534static int iio_compute_scan_bytes(struct iio_dev *indio_dev,
535 const unsigned long *mask, bool timestamp)
536{
537 unsigned bytes = 0;
538 int length, i;
539
540 /* How much space will the demuxed element take? */
541 for_each_set_bit(i, mask,
542 indio_dev->masklength) {
543 length = iio_storage_bytes_for_si(indio_dev, i);
544 bytes = ALIGN(bytes, length);
545 bytes += length;
546 }
547
548 if (timestamp) {
549 length = iio_storage_bytes_for_timestamp(indio_dev);
550 bytes = ALIGN(bytes, length);
551 bytes += length;
552 }
553 return bytes;
554}
555
556static void iio_buffer_activate(struct iio_dev *indio_dev,
557 struct iio_buffer *buffer)
558{
559 iio_buffer_get(buffer);
560 list_add(&buffer->buffer_list, &indio_dev->buffer_list);
561}
562
563static void iio_buffer_deactivate(struct iio_buffer *buffer)
564{
565 list_del_init(&buffer->buffer_list);
566 wake_up_interruptible(&buffer->pollq);
567 iio_buffer_put(buffer);
568}
569
570static void iio_buffer_deactivate_all(struct iio_dev *indio_dev)
571{
572 struct iio_buffer *buffer, *_buffer;
573
574 list_for_each_entry_safe(buffer, _buffer,
575 &indio_dev->buffer_list, buffer_list)
576 iio_buffer_deactivate(buffer);
577}
578
579static int iio_buffer_enable(struct iio_buffer *buffer,
580 struct iio_dev *indio_dev)
581{
582 if (!buffer->access->enable)
583 return 0;
584 return buffer->access->enable(buffer, indio_dev);
585}
586
587static int iio_buffer_disable(struct iio_buffer *buffer,
588 struct iio_dev *indio_dev)
589{
590 if (!buffer->access->disable)
591 return 0;
592 return buffer->access->disable(buffer, indio_dev);
593}
594
595static void iio_buffer_update_bytes_per_datum(struct iio_dev *indio_dev,
596 struct iio_buffer *buffer)
597{
598 unsigned int bytes;
599
600 if (!buffer->access->set_bytes_per_datum)
601 return;
602
603 bytes = iio_compute_scan_bytes(indio_dev, buffer->scan_mask,
604 buffer->scan_timestamp);
605
606 buffer->access->set_bytes_per_datum(buffer, bytes);
607}
608
609static int iio_buffer_request_update(struct iio_dev *indio_dev,
610 struct iio_buffer *buffer)
611{
612 int ret;
613
614 iio_buffer_update_bytes_per_datum(indio_dev, buffer);
615 if (buffer->access->request_update) {
616 ret = buffer->access->request_update(buffer);
617 if (ret) {
618 dev_dbg(&indio_dev->dev,
619 "Buffer not started: buffer parameter update failed (%d)\n",
620 ret);
621 return ret;
622 }
623 }
624
625 return 0;
626}
627
628static void iio_free_scan_mask(struct iio_dev *indio_dev,
629 const unsigned long *mask)
630{
631 /* If the mask is dynamically allocated free it, otherwise do nothing */
632 if (!indio_dev->available_scan_masks)
633 kfree(mask);
634}
635
636struct iio_device_config {
637 unsigned int mode;
638 unsigned int watermark;
639 const unsigned long *scan_mask;
640 unsigned int scan_bytes;
641 bool scan_timestamp;
642};
643
644static int iio_verify_update(struct iio_dev *indio_dev,
645 struct iio_buffer *insert_buffer, struct iio_buffer *remove_buffer,
646 struct iio_device_config *config)
647{
648 unsigned long *compound_mask;
649 const unsigned long *scan_mask;
650 bool strict_scanmask = false;
651 struct iio_buffer *buffer;
652 bool scan_timestamp;
653 unsigned int modes;
654
655 memset(config, 0, sizeof(*config));
656 config->watermark = ~0;
657
658 /*
659 * If there is just one buffer and we are removing it there is nothing
660 * to verify.
661 */
662 if (remove_buffer && !insert_buffer &&
663 list_is_singular(&indio_dev->buffer_list))
664 return 0;
665
666 modes = indio_dev->modes;
667
668 list_for_each_entry(buffer, &indio_dev->buffer_list, buffer_list) {
669 if (buffer == remove_buffer)
670 continue;
671 modes &= buffer->access->modes;
672 config->watermark = min(config->watermark, buffer->watermark);
673 }
674
675 if (insert_buffer) {
676 modes &= insert_buffer->access->modes;
677 config->watermark = min(config->watermark,
678 insert_buffer->watermark);
679 }
680
681 /* Definitely possible for devices to support both of these. */
682 if ((modes & INDIO_BUFFER_TRIGGERED) && indio_dev->trig) {
683 config->mode = INDIO_BUFFER_TRIGGERED;
684 } else if (modes & INDIO_BUFFER_HARDWARE) {
685 /*
686 * Keep things simple for now and only allow a single buffer to
687 * be connected in hardware mode.
688 */
689 if (insert_buffer && !list_empty(&indio_dev->buffer_list))
690 return -EINVAL;
691 config->mode = INDIO_BUFFER_HARDWARE;
692 strict_scanmask = true;
693 } else if (modes & INDIO_BUFFER_SOFTWARE) {
694 config->mode = INDIO_BUFFER_SOFTWARE;
695 } else {
696 /* Can only occur on first buffer */
697 if (indio_dev->modes & INDIO_BUFFER_TRIGGERED)
698 dev_dbg(&indio_dev->dev, "Buffer not started: no trigger\n");
699 return -EINVAL;
700 }
701
702 /* What scan mask do we actually have? */
703 compound_mask = kcalloc(BITS_TO_LONGS(indio_dev->masklength),
704 sizeof(long), GFP_KERNEL);
705 if (compound_mask == NULL)
706 return -ENOMEM;
707
708 scan_timestamp = false;
709
710 list_for_each_entry(buffer, &indio_dev->buffer_list, buffer_list) {
711 if (buffer == remove_buffer)
712 continue;
713 bitmap_or(compound_mask, compound_mask, buffer->scan_mask,
714 indio_dev->masklength);
715 scan_timestamp |= buffer->scan_timestamp;
716 }
717
718 if (insert_buffer) {
719 bitmap_or(compound_mask, compound_mask,
720 insert_buffer->scan_mask, indio_dev->masklength);
721 scan_timestamp |= insert_buffer->scan_timestamp;
722 }
723
724 if (indio_dev->available_scan_masks) {
725 scan_mask = iio_scan_mask_match(indio_dev->available_scan_masks,
726 indio_dev->masklength,
727 compound_mask,
728 strict_scanmask);
729 kfree(compound_mask);
730 if (scan_mask == NULL)
731 return -EINVAL;
732 } else {
733 scan_mask = compound_mask;
734 }
735
736 config->scan_bytes = iio_compute_scan_bytes(indio_dev,
737 scan_mask, scan_timestamp);
738 config->scan_mask = scan_mask;
739 config->scan_timestamp = scan_timestamp;
740
741 return 0;
742}
743
744static int iio_enable_buffers(struct iio_dev *indio_dev,
745 struct iio_device_config *config)
746{
747 struct iio_buffer *buffer;
748 int ret;
749
750 indio_dev->active_scan_mask = config->scan_mask;
751 indio_dev->scan_timestamp = config->scan_timestamp;
752 indio_dev->scan_bytes = config->scan_bytes;
753
754 iio_update_demux(indio_dev);
755
756 /* Wind up again */
757 if (indio_dev->setup_ops->preenable) {
758 ret = indio_dev->setup_ops->preenable(indio_dev);
759 if (ret) {
760 dev_dbg(&indio_dev->dev,
761 "Buffer not started: buffer preenable failed (%d)\n", ret);
762 goto err_undo_config;
763 }
764 }
765
766 if (indio_dev->info->update_scan_mode) {
767 ret = indio_dev->info
768 ->update_scan_mode(indio_dev,
769 indio_dev->active_scan_mask);
770 if (ret < 0) {
771 dev_dbg(&indio_dev->dev,
772 "Buffer not started: update scan mode failed (%d)\n",
773 ret);
774 goto err_run_postdisable;
775 }
776 }
777
778 if (indio_dev->info->hwfifo_set_watermark)
779 indio_dev->info->hwfifo_set_watermark(indio_dev,
780 config->watermark);
781
782 list_for_each_entry(buffer, &indio_dev->buffer_list, buffer_list) {
783 ret = iio_buffer_enable(buffer, indio_dev);
784 if (ret)
785 goto err_disable_buffers;
786 }
787
788 indio_dev->currentmode = config->mode;
789
790 if (indio_dev->setup_ops->postenable) {
791 ret = indio_dev->setup_ops->postenable(indio_dev);
792 if (ret) {
793 dev_dbg(&indio_dev->dev,
794 "Buffer not started: postenable failed (%d)\n", ret);
795 goto err_disable_buffers;
796 }
797 }
798
799 return 0;
800
801err_disable_buffers:
802 list_for_each_entry_continue_reverse(buffer, &indio_dev->buffer_list,
803 buffer_list)
804 iio_buffer_disable(buffer, indio_dev);
805err_run_postdisable:
806 indio_dev->currentmode = INDIO_DIRECT_MODE;
807 if (indio_dev->setup_ops->postdisable)
808 indio_dev->setup_ops->postdisable(indio_dev);
809err_undo_config:
810 indio_dev->active_scan_mask = NULL;
811
812 return ret;
813}
814
815static int iio_disable_buffers(struct iio_dev *indio_dev)
816{
817 struct iio_buffer *buffer;
818 int ret = 0;
819 int ret2;
820
821 /* Wind down existing buffers - iff there are any */
822 if (list_empty(&indio_dev->buffer_list))
823 return 0;
824
825 /*
826 * If things go wrong at some step in disable we still need to continue
827 * to perform the other steps, otherwise we leave the device in a
828 * inconsistent state. We return the error code for the first error we
829 * encountered.
830 */
831
832 if (indio_dev->setup_ops->predisable) {
833 ret2 = indio_dev->setup_ops->predisable(indio_dev);
834 if (ret2 && !ret)
835 ret = ret2;
836 }
837
838 list_for_each_entry(buffer, &indio_dev->buffer_list, buffer_list) {
839 ret2 = iio_buffer_disable(buffer, indio_dev);
840 if (ret2 && !ret)
841 ret = ret2;
842 }
843
844 indio_dev->currentmode = INDIO_DIRECT_MODE;
845
846 if (indio_dev->setup_ops->postdisable) {
847 ret2 = indio_dev->setup_ops->postdisable(indio_dev);
848 if (ret2 && !ret)
849 ret = ret2;
850 }
851
852 iio_free_scan_mask(indio_dev, indio_dev->active_scan_mask);
853 indio_dev->active_scan_mask = NULL;
854
855 return ret;
856}
857
858static int __iio_update_buffers(struct iio_dev *indio_dev,
859 struct iio_buffer *insert_buffer,
860 struct iio_buffer *remove_buffer)
861{
862 struct iio_device_config new_config;
863 int ret;
864
865 ret = iio_verify_update(indio_dev, insert_buffer, remove_buffer,
866 &new_config);
867 if (ret)
868 return ret;
869
870 if (insert_buffer) {
871 ret = iio_buffer_request_update(indio_dev, insert_buffer);
872 if (ret)
873 goto err_free_config;
874 }
875
876 ret = iio_disable_buffers(indio_dev);
877 if (ret)
878 goto err_deactivate_all;
879
880 if (remove_buffer)
881 iio_buffer_deactivate(remove_buffer);
882 if (insert_buffer)
883 iio_buffer_activate(indio_dev, insert_buffer);
884
885 /* If no buffers in list, we are done */
886 if (list_empty(&indio_dev->buffer_list))
887 return 0;
888
889 ret = iio_enable_buffers(indio_dev, &new_config);
890 if (ret)
891 goto err_deactivate_all;
892
893 return 0;
894
895err_deactivate_all:
896 /*
897 * We've already verified that the config is valid earlier. If things go
898 * wrong in either enable or disable the most likely reason is an IO
899 * error from the device. In this case there is no good recovery
900 * strategy. Just make sure to disable everything and leave the device
901 * in a sane state. With a bit of luck the device might come back to
902 * life again later and userspace can try again.
903 */
904 iio_buffer_deactivate_all(indio_dev);
905
906err_free_config:
907 iio_free_scan_mask(indio_dev, new_config.scan_mask);
908 return ret;
909}
910
911int iio_update_buffers(struct iio_dev *indio_dev,
912 struct iio_buffer *insert_buffer,
913 struct iio_buffer *remove_buffer)
914{
915 int ret;
916
917 if (insert_buffer == remove_buffer)
918 return 0;
919
920 mutex_lock(&indio_dev->info_exist_lock);
921 mutex_lock(&indio_dev->mlock);
922
923 if (insert_buffer && iio_buffer_is_active(insert_buffer))
924 insert_buffer = NULL;
925
926 if (remove_buffer && !iio_buffer_is_active(remove_buffer))
927 remove_buffer = NULL;
928
929 if (!insert_buffer && !remove_buffer) {
930 ret = 0;
931 goto out_unlock;
932 }
933
934 if (indio_dev->info == NULL) {
935 ret = -ENODEV;
936 goto out_unlock;
937 }
938
939 ret = __iio_update_buffers(indio_dev, insert_buffer, remove_buffer);
940
941out_unlock:
942 mutex_unlock(&indio_dev->mlock);
943 mutex_unlock(&indio_dev->info_exist_lock);
944
945 return ret;
946}
947EXPORT_SYMBOL_GPL(iio_update_buffers);
948
949void iio_disable_all_buffers(struct iio_dev *indio_dev)
950{
951 iio_disable_buffers(indio_dev);
952 iio_buffer_deactivate_all(indio_dev);
953}
954
955static ssize_t iio_buffer_store_enable(struct device *dev,
956 struct device_attribute *attr,
957 const char *buf,
958 size_t len)
959{
960 int ret;
961 bool requested_state;
962 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
963 bool inlist;
964
965 ret = strtobool(buf, &requested_state);
966 if (ret < 0)
967 return ret;
968
969 mutex_lock(&indio_dev->mlock);
970
971 /* Find out if it is in the list */
972 inlist = iio_buffer_is_active(indio_dev->buffer);
973 /* Already in desired state */
974 if (inlist == requested_state)
975 goto done;
976
977 if (requested_state)
978 ret = __iio_update_buffers(indio_dev,
979 indio_dev->buffer, NULL);
980 else
981 ret = __iio_update_buffers(indio_dev,
982 NULL, indio_dev->buffer);
983
984done:
985 mutex_unlock(&indio_dev->mlock);
986 return (ret < 0) ? ret : len;
987}
988
989static const char * const iio_scan_elements_group_name = "scan_elements";
990
991static ssize_t iio_buffer_show_watermark(struct device *dev,
992 struct device_attribute *attr,
993 char *buf)
994{
995 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
996 struct iio_buffer *buffer = indio_dev->buffer;
997
998 return sprintf(buf, "%u\n", buffer->watermark);
999}
1000
1001static ssize_t iio_buffer_store_watermark(struct device *dev,
1002 struct device_attribute *attr,
1003 const char *buf,
1004 size_t len)
1005{
1006 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
1007 struct iio_buffer *buffer = indio_dev->buffer;
1008 unsigned int val;
1009 int ret;
1010
1011 ret = kstrtouint(buf, 10, &val);
1012 if (ret)
1013 return ret;
1014 if (!val)
1015 return -EINVAL;
1016
1017 mutex_lock(&indio_dev->mlock);
1018
1019 if (val > buffer->length) {
1020 ret = -EINVAL;
1021 goto out;
1022 }
1023
1024 if (iio_buffer_is_active(indio_dev->buffer)) {
1025 ret = -EBUSY;
1026 goto out;
1027 }
1028
1029 buffer->watermark = val;
1030out:
1031 mutex_unlock(&indio_dev->mlock);
1032
1033 return ret ? ret : len;
1034}
1035
1036static DEVICE_ATTR(length, S_IRUGO | S_IWUSR, iio_buffer_read_length,
1037 iio_buffer_write_length);
1038static struct device_attribute dev_attr_length_ro = __ATTR(length,
1039 S_IRUGO, iio_buffer_read_length, NULL);
1040static DEVICE_ATTR(enable, S_IRUGO | S_IWUSR,
1041 iio_buffer_show_enable, iio_buffer_store_enable);
1042static DEVICE_ATTR(watermark, S_IRUGO | S_IWUSR,
1043 iio_buffer_show_watermark, iio_buffer_store_watermark);
1044static struct device_attribute dev_attr_watermark_ro = __ATTR(watermark,
1045 S_IRUGO, iio_buffer_show_watermark, NULL);
1046
1047static struct attribute *iio_buffer_attrs[] = {
1048 &dev_attr_length.attr,
1049 &dev_attr_enable.attr,
1050 &dev_attr_watermark.attr,
1051};
1052
1053int iio_buffer_alloc_sysfs_and_mask(struct iio_dev *indio_dev)
1054{
1055 struct iio_dev_attr *p;
1056 struct attribute **attr;
1057 struct iio_buffer *buffer = indio_dev->buffer;
1058 int ret, i, attrn, attrcount, attrcount_orig = 0;
1059 const struct iio_chan_spec *channels;
1060
1061 channels = indio_dev->channels;
1062 if (channels) {
1063 int ml = indio_dev->masklength;
1064
1065 for (i = 0; i < indio_dev->num_channels; i++)
1066 ml = max(ml, channels[i].scan_index + 1);
1067 indio_dev->masklength = ml;
1068 }
1069
1070 if (!buffer)
1071 return 0;
1072
1073 attrcount = 0;
1074 if (buffer->attrs) {
1075 while (buffer->attrs[attrcount] != NULL)
1076 attrcount++;
1077 }
1078
1079 attr = kcalloc(attrcount + ARRAY_SIZE(iio_buffer_attrs) + 1,
1080 sizeof(struct attribute *), GFP_KERNEL);
1081 if (!attr)
1082 return -ENOMEM;
1083
1084 memcpy(attr, iio_buffer_attrs, sizeof(iio_buffer_attrs));
1085 if (!buffer->access->set_length)
1086 attr[0] = &dev_attr_length_ro.attr;
1087
1088 if (buffer->access->flags & INDIO_BUFFER_FLAG_FIXED_WATERMARK)
1089 attr[2] = &dev_attr_watermark_ro.attr;
1090
1091 if (buffer->attrs)
1092 memcpy(&attr[ARRAY_SIZE(iio_buffer_attrs)], buffer->attrs,
1093 sizeof(struct attribute *) * attrcount);
1094
1095 attr[attrcount + ARRAY_SIZE(iio_buffer_attrs)] = NULL;
1096
1097 buffer->buffer_group.name = "buffer";
1098 buffer->buffer_group.attrs = attr;
1099
1100 indio_dev->groups[indio_dev->groupcounter++] = &buffer->buffer_group;
1101
1102 if (buffer->scan_el_attrs != NULL) {
1103 attr = buffer->scan_el_attrs->attrs;
1104 while (*attr++ != NULL)
1105 attrcount_orig++;
1106 }
1107 attrcount = attrcount_orig;
1108 INIT_LIST_HEAD(&buffer->scan_el_dev_attr_list);
1109 channels = indio_dev->channels;
1110 if (channels) {
1111 /* new magic */
1112 for (i = 0; i < indio_dev->num_channels; i++) {
1113 if (channels[i].scan_index < 0)
1114 continue;
1115
1116 ret = iio_buffer_add_channel_sysfs(indio_dev,
1117 &channels[i]);
1118 if (ret < 0)
1119 goto error_cleanup_dynamic;
1120 attrcount += ret;
1121 if (channels[i].type == IIO_TIMESTAMP)
1122 indio_dev->scan_index_timestamp =
1123 channels[i].scan_index;
1124 }
1125 if (indio_dev->masklength && buffer->scan_mask == NULL) {
1126 buffer->scan_mask = kcalloc(BITS_TO_LONGS(indio_dev->masklength),
1127 sizeof(*buffer->scan_mask),
1128 GFP_KERNEL);
1129 if (buffer->scan_mask == NULL) {
1130 ret = -ENOMEM;
1131 goto error_cleanup_dynamic;
1132 }
1133 }
1134 }
1135
1136 buffer->scan_el_group.name = iio_scan_elements_group_name;
1137
1138 buffer->scan_el_group.attrs = kcalloc(attrcount + 1,
1139 sizeof(buffer->scan_el_group.attrs[0]),
1140 GFP_KERNEL);
1141 if (buffer->scan_el_group.attrs == NULL) {
1142 ret = -ENOMEM;
1143 goto error_free_scan_mask;
1144 }
1145 if (buffer->scan_el_attrs)
1146 memcpy(buffer->scan_el_group.attrs, buffer->scan_el_attrs,
1147 sizeof(buffer->scan_el_group.attrs[0])*attrcount_orig);
1148 attrn = attrcount_orig;
1149
1150 list_for_each_entry(p, &buffer->scan_el_dev_attr_list, l)
1151 buffer->scan_el_group.attrs[attrn++] = &p->dev_attr.attr;
1152 indio_dev->groups[indio_dev->groupcounter++] = &buffer->scan_el_group;
1153
1154 return 0;
1155
1156error_free_scan_mask:
1157 kfree(buffer->scan_mask);
1158error_cleanup_dynamic:
1159 iio_free_chan_devattr_list(&buffer->scan_el_dev_attr_list);
1160 kfree(indio_dev->buffer->buffer_group.attrs);
1161
1162 return ret;
1163}
1164
1165void iio_buffer_free_sysfs_and_mask(struct iio_dev *indio_dev)
1166{
1167 if (!indio_dev->buffer)
1168 return;
1169
1170 kfree(indio_dev->buffer->scan_mask);
1171 kfree(indio_dev->buffer->buffer_group.attrs);
1172 kfree(indio_dev->buffer->scan_el_group.attrs);
1173 iio_free_chan_devattr_list(&indio_dev->buffer->scan_el_dev_attr_list);
1174}
1175
1176/**
1177 * iio_validate_scan_mask_onehot() - Validates that exactly one channel is selected
1178 * @indio_dev: the iio device
1179 * @mask: scan mask to be checked
1180 *
1181 * Return true if exactly one bit is set in the scan mask, false otherwise. It
1182 * can be used for devices where only one channel can be active for sampling at
1183 * a time.
1184 */
1185bool iio_validate_scan_mask_onehot(struct iio_dev *indio_dev,
1186 const unsigned long *mask)
1187{
1188 return bitmap_weight(mask, indio_dev->masklength) == 1;
1189}
1190EXPORT_SYMBOL_GPL(iio_validate_scan_mask_onehot);
1191
1192int iio_scan_mask_query(struct iio_dev *indio_dev,
1193 struct iio_buffer *buffer, int bit)
1194{
1195 if (bit > indio_dev->masklength)
1196 return -EINVAL;
1197
1198 if (!buffer->scan_mask)
1199 return 0;
1200
1201 /* Ensure return value is 0 or 1. */
1202 return !!test_bit(bit, buffer->scan_mask);
1203};
1204EXPORT_SYMBOL_GPL(iio_scan_mask_query);
1205
1206/**
1207 * struct iio_demux_table - table describing demux memcpy ops
1208 * @from: index to copy from
1209 * @to: index to copy to
1210 * @length: how many bytes to copy
1211 * @l: list head used for management
1212 */
1213struct iio_demux_table {
1214 unsigned from;
1215 unsigned to;
1216 unsigned length;
1217 struct list_head l;
1218};
1219
1220static const void *iio_demux(struct iio_buffer *buffer,
1221 const void *datain)
1222{
1223 struct iio_demux_table *t;
1224
1225 if (list_empty(&buffer->demux_list))
1226 return datain;
1227 list_for_each_entry(t, &buffer->demux_list, l)
1228 memcpy(buffer->demux_bounce + t->to,
1229 datain + t->from, t->length);
1230
1231 return buffer->demux_bounce;
1232}
1233
1234static int iio_push_to_buffer(struct iio_buffer *buffer, const void *data)
1235{
1236 const void *dataout = iio_demux(buffer, data);
1237 int ret;
1238
1239 ret = buffer->access->store_to(buffer, dataout);
1240 if (ret)
1241 return ret;
1242
1243 /*
1244 * We can't just test for watermark to decide if we wake the poll queue
1245 * because read may request less samples than the watermark.
1246 */
1247 wake_up_interruptible_poll(&buffer->pollq, POLLIN | POLLRDNORM);
1248 return 0;
1249}
1250
1251static void iio_buffer_demux_free(struct iio_buffer *buffer)
1252{
1253 struct iio_demux_table *p, *q;
1254 list_for_each_entry_safe(p, q, &buffer->demux_list, l) {
1255 list_del(&p->l);
1256 kfree(p);
1257 }
1258}
1259
1260
1261int iio_push_to_buffers(struct iio_dev *indio_dev, const void *data)
1262{
1263 int ret;
1264 struct iio_buffer *buf;
1265
1266 list_for_each_entry(buf, &indio_dev->buffer_list, buffer_list) {
1267 ret = iio_push_to_buffer(buf, data);
1268 if (ret < 0)
1269 return ret;
1270 }
1271
1272 return 0;
1273}
1274EXPORT_SYMBOL_GPL(iio_push_to_buffers);
1275
1276static int iio_buffer_add_demux(struct iio_buffer *buffer,
1277 struct iio_demux_table **p, unsigned int in_loc, unsigned int out_loc,
1278 unsigned int length)
1279{
1280
1281 if (*p && (*p)->from + (*p)->length == in_loc &&
1282 (*p)->to + (*p)->length == out_loc) {
1283 (*p)->length += length;
1284 } else {
1285 *p = kmalloc(sizeof(**p), GFP_KERNEL);
1286 if (*p == NULL)
1287 return -ENOMEM;
1288 (*p)->from = in_loc;
1289 (*p)->to = out_loc;
1290 (*p)->length = length;
1291 list_add_tail(&(*p)->l, &buffer->demux_list);
1292 }
1293
1294 return 0;
1295}
1296
1297static int iio_buffer_update_demux(struct iio_dev *indio_dev,
1298 struct iio_buffer *buffer)
1299{
1300 int ret, in_ind = -1, out_ind, length;
1301 unsigned in_loc = 0, out_loc = 0;
1302 struct iio_demux_table *p = NULL;
1303
1304 /* Clear out any old demux */
1305 iio_buffer_demux_free(buffer);
1306 kfree(buffer->demux_bounce);
1307 buffer->demux_bounce = NULL;
1308
1309 /* First work out which scan mode we will actually have */
1310 if (bitmap_equal(indio_dev->active_scan_mask,
1311 buffer->scan_mask,
1312 indio_dev->masklength))
1313 return 0;
1314
1315 /* Now we have the two masks, work from least sig and build up sizes */
1316 for_each_set_bit(out_ind,
1317 buffer->scan_mask,
1318 indio_dev->masklength) {
1319 in_ind = find_next_bit(indio_dev->active_scan_mask,
1320 indio_dev->masklength,
1321 in_ind + 1);
1322 while (in_ind != out_ind) {
1323 in_ind = find_next_bit(indio_dev->active_scan_mask,
1324 indio_dev->masklength,
1325 in_ind + 1);
1326 length = iio_storage_bytes_for_si(indio_dev, in_ind);
1327 /* Make sure we are aligned */
1328 in_loc = roundup(in_loc, length) + length;
1329 }
1330 length = iio_storage_bytes_for_si(indio_dev, in_ind);
1331 out_loc = roundup(out_loc, length);
1332 in_loc = roundup(in_loc, length);
1333 ret = iio_buffer_add_demux(buffer, &p, in_loc, out_loc, length);
1334 if (ret)
1335 goto error_clear_mux_table;
1336 out_loc += length;
1337 in_loc += length;
1338 }
1339 /* Relies on scan_timestamp being last */
1340 if (buffer->scan_timestamp) {
1341 length = iio_storage_bytes_for_timestamp(indio_dev);
1342 out_loc = roundup(out_loc, length);
1343 in_loc = roundup(in_loc, length);
1344 ret = iio_buffer_add_demux(buffer, &p, in_loc, out_loc, length);
1345 if (ret)
1346 goto error_clear_mux_table;
1347 out_loc += length;
1348 in_loc += length;
1349 }
1350 buffer->demux_bounce = kzalloc(out_loc, GFP_KERNEL);
1351 if (buffer->demux_bounce == NULL) {
1352 ret = -ENOMEM;
1353 goto error_clear_mux_table;
1354 }
1355 return 0;
1356
1357error_clear_mux_table:
1358 iio_buffer_demux_free(buffer);
1359
1360 return ret;
1361}
1362
1363int iio_update_demux(struct iio_dev *indio_dev)
1364{
1365 struct iio_buffer *buffer;
1366 int ret;
1367
1368 list_for_each_entry(buffer, &indio_dev->buffer_list, buffer_list) {
1369 ret = iio_buffer_update_demux(indio_dev, buffer);
1370 if (ret < 0)
1371 goto error_clear_mux_table;
1372 }
1373 return 0;
1374
1375error_clear_mux_table:
1376 list_for_each_entry(buffer, &indio_dev->buffer_list, buffer_list)
1377 iio_buffer_demux_free(buffer);
1378
1379 return ret;
1380}
1381EXPORT_SYMBOL_GPL(iio_update_demux);
1382
1383/**
1384 * iio_buffer_release() - Free a buffer's resources
1385 * @ref: Pointer to the kref embedded in the iio_buffer struct
1386 *
1387 * This function is called when the last reference to the buffer has been
1388 * dropped. It will typically free all resources allocated by the buffer. Do not
1389 * call this function manually, always use iio_buffer_put() when done using a
1390 * buffer.
1391 */
1392static void iio_buffer_release(struct kref *ref)
1393{
1394 struct iio_buffer *buffer = container_of(ref, struct iio_buffer, ref);
1395
1396 buffer->access->release(buffer);
1397}
1398
1399/**
1400 * iio_buffer_get() - Grab a reference to the buffer
1401 * @buffer: The buffer to grab a reference for, may be NULL
1402 *
1403 * Returns the pointer to the buffer that was passed into the function.
1404 */
1405struct iio_buffer *iio_buffer_get(struct iio_buffer *buffer)
1406{
1407 if (buffer)
1408 kref_get(&buffer->ref);
1409
1410 return buffer;
1411}
1412EXPORT_SYMBOL_GPL(iio_buffer_get);
1413
1414/**
1415 * iio_buffer_put() - Release the reference to the buffer
1416 * @buffer: The buffer to release the reference for, may be NULL
1417 */
1418void iio_buffer_put(struct iio_buffer *buffer)
1419{
1420 if (buffer)
1421 kref_put(&buffer->ref, iio_buffer_release);
1422}
1423EXPORT_SYMBOL_GPL(iio_buffer_put);
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);