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scsi: target/iscsi: Make iscsit_ta_authentication() respect the output buffer size
[linux/fpc-iii.git] / drivers / iio / industrialio-buffer.c
blob961afb5588be0546793629702578c9d1a8ccc944
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
30 static const char * const iio_endian_prefix[] = {
31 [IIO_BE] = "be",
32 [IIO_LE] = "le",
33 };
34
35 static bool iio_buffer_is_active(struct iio_buffer *buf)
36 {
37 return !list_empty(&buf->buffer_list);
38 }
39
40 static size_t iio_buffer_data_available(struct iio_buffer *buf)
41 {
42 return buf->access->data_available(buf);
43 }
44
45 static 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
54 static 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 **/
105 ssize_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 DEFINE_WAIT_FUNC(wait, woken_wake_function);
111 size_t datum_size;
112 size_t to_wait;
113 int ret = 0;
114
115 if (!indio_dev->info)
116 return -ENODEV;
117
118 if (!rb || !rb->access->read_first_n)
119 return -EINVAL;
120
121 datum_size = rb->bytes_per_datum;
122
123 /*
124 * If datum_size is 0 there will never be anything to read from the
125 * buffer, so signal end of file now.
126 */
127 if (!datum_size)
128 return 0;
129
130 if (filp->f_flags & O_NONBLOCK)
131 to_wait = 0;
132 else
133 to_wait = min_t(size_t, n / datum_size, rb->watermark);
134
135 add_wait_queue(&rb->pollq, &wait);
136 do {
137 if (!indio_dev->info) {
138 ret = -ENODEV;
139 break;
140 }
141
142 if (!iio_buffer_ready(indio_dev, rb, to_wait, n / datum_size)) {
143 if (signal_pending(current)) {
144 ret = -ERESTARTSYS;
145 break;
146 }
147
148 wait_woken(&wait, TASK_INTERRUPTIBLE,
149 MAX_SCHEDULE_TIMEOUT);
150 continue;
151 }
152
153 ret = rb->access->read_first_n(rb, n, buf);
154 if (ret == 0 && (filp->f_flags & O_NONBLOCK))
155 ret = -EAGAIN;
156 } while (ret == 0);
157 remove_wait_queue(&rb->pollq, &wait);
158
159 return ret;
160 }
161
162 /**
163 * iio_buffer_poll() - poll the buffer to find out if it has data
164 * @filp: File structure pointer for device access
165 * @wait: Poll table structure pointer for which the driver adds
166 * a wait queue
167 *
168 * Return: (POLLIN | POLLRDNORM) if data is available for reading
169 * or 0 for other cases
170 */
171 unsigned int iio_buffer_poll(struct file *filp,
172 struct poll_table_struct *wait)
173 {
174 struct iio_dev *indio_dev = filp->private_data;
175 struct iio_buffer *rb = indio_dev->buffer;
176
177 if (!indio_dev->info || rb == NULL)
178 return 0;
179
180 poll_wait(filp, &rb->pollq, wait);
181 if (iio_buffer_ready(indio_dev, rb, rb->watermark, 0))
182 return POLLIN | POLLRDNORM;
183 return 0;
184 }
185
186 /**
187 * iio_buffer_wakeup_poll - Wakes up the buffer waitqueue
188 * @indio_dev: The IIO device
189 *
190 * Wakes up the event waitqueue used for poll(). Should usually
191 * be called when the device is unregistered.
192 */
193 void iio_buffer_wakeup_poll(struct iio_dev *indio_dev)
194 {
195 if (!indio_dev->buffer)
196 return;
197
198 wake_up(&indio_dev->buffer->pollq);
199 }
200
201 void iio_buffer_init(struct iio_buffer *buffer)
202 {
203 INIT_LIST_HEAD(&buffer->demux_list);
204 INIT_LIST_HEAD(&buffer->buffer_list);
205 init_waitqueue_head(&buffer->pollq);
206 kref_init(&buffer->ref);
207 buffer->watermark = 1;
208 }
209 EXPORT_SYMBOL(iio_buffer_init);
210
211 static ssize_t iio_show_scan_index(struct device *dev,
212 struct device_attribute *attr,
213 char *buf)
214 {
215 return sprintf(buf, "%u\n", to_iio_dev_attr(attr)->c->scan_index);
216 }
217
218 static ssize_t iio_show_fixed_type(struct device *dev,
219 struct device_attribute *attr,
220 char *buf)
221 {
222 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
223 u8 type = this_attr->c->scan_type.endianness;
224
225 if (type == IIO_CPU) {
226 #ifdef __LITTLE_ENDIAN
227 type = IIO_LE;
228 #else
229 type = IIO_BE;
230 #endif
231 }
232 if (this_attr->c->scan_type.repeat > 1)
233 return sprintf(buf, "%s:%c%d/%dX%d>>%u\n",
234 iio_endian_prefix[type],
235 this_attr->c->scan_type.sign,
236 this_attr->c->scan_type.realbits,
237 this_attr->c->scan_type.storagebits,
238 this_attr->c->scan_type.repeat,
239 this_attr->c->scan_type.shift);
240 else
241 return sprintf(buf, "%s:%c%d/%d>>%u\n",
242 iio_endian_prefix[type],
243 this_attr->c->scan_type.sign,
244 this_attr->c->scan_type.realbits,
245 this_attr->c->scan_type.storagebits,
246 this_attr->c->scan_type.shift);
247 }
248
249 static ssize_t iio_scan_el_show(struct device *dev,
250 struct device_attribute *attr,
251 char *buf)
252 {
253 int ret;
254 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
255
256 /* Ensure ret is 0 or 1. */
257 ret = !!test_bit(to_iio_dev_attr(attr)->address,
258 indio_dev->buffer->scan_mask);
259
260 return sprintf(buf, "%d\n", ret);
261 }
262
263 /* Note NULL used as error indicator as it doesn't make sense. */
264 static const unsigned long *iio_scan_mask_match(const unsigned long *av_masks,
265 unsigned int masklength,
266 const unsigned long *mask,
267 bool strict)
268 {
269 if (bitmap_empty(mask, masklength))
270 return NULL;
271 while (*av_masks) {
272 if (strict) {
273 if (bitmap_equal(mask, av_masks, masklength))
274 return av_masks;
275 } else {
276 if (bitmap_subset(mask, av_masks, masklength))
277 return av_masks;
278 }
279 av_masks += BITS_TO_LONGS(masklength);
280 }
281 return NULL;
282 }
283
284 static bool iio_validate_scan_mask(struct iio_dev *indio_dev,
285 const unsigned long *mask)
286 {
287 if (!indio_dev->setup_ops->validate_scan_mask)
288 return true;
289
290 return indio_dev->setup_ops->validate_scan_mask(indio_dev, mask);
291 }
292
293 /**
294 * iio_scan_mask_set() - set particular bit in the scan mask
295 * @indio_dev: the iio device
296 * @buffer: the buffer whose scan mask we are interested in
297 * @bit: the bit to be set.
298 *
299 * Note that at this point we have no way of knowing what other
300 * buffers might request, hence this code only verifies that the
301 * individual buffers request is plausible.
302 */
303 static int iio_scan_mask_set(struct iio_dev *indio_dev,
304 struct iio_buffer *buffer, int bit)
305 {
306 const unsigned long *mask;
307 unsigned long *trialmask;
308
309 trialmask = kmalloc(sizeof(*trialmask)*
310 BITS_TO_LONGS(indio_dev->masklength),
311 GFP_KERNEL);
312
313 if (trialmask == NULL)
314 return -ENOMEM;
315 if (!indio_dev->masklength) {
316 WARN(1, "Trying to set scanmask prior to registering buffer\n");
317 goto err_invalid_mask;
318 }
319 bitmap_copy(trialmask, buffer->scan_mask, indio_dev->masklength);
320 set_bit(bit, trialmask);
321
322 if (!iio_validate_scan_mask(indio_dev, trialmask))
323 goto err_invalid_mask;
324
325 if (indio_dev->available_scan_masks) {
326 mask = iio_scan_mask_match(indio_dev->available_scan_masks,
327 indio_dev->masklength,
328 trialmask, false);
329 if (!mask)
330 goto err_invalid_mask;
331 }
332 bitmap_copy(buffer->scan_mask, trialmask, indio_dev->masklength);
333
334 kfree(trialmask);
335
336 return 0;
337
338 err_invalid_mask:
339 kfree(trialmask);
340 return -EINVAL;
341 }
342
343 static int iio_scan_mask_clear(struct iio_buffer *buffer, int bit)
344 {
345 clear_bit(bit, buffer->scan_mask);
346 return 0;
347 }
348
349 static ssize_t iio_scan_el_store(struct device *dev,
350 struct device_attribute *attr,
351 const char *buf,
352 size_t len)
353 {
354 int ret;
355 bool state;
356 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
357 struct iio_buffer *buffer = indio_dev->buffer;
358 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
359
360 ret = strtobool(buf, &state);
361 if (ret < 0)
362 return ret;
363 mutex_lock(&indio_dev->mlock);
364 if (iio_buffer_is_active(indio_dev->buffer)) {
365 ret = -EBUSY;
366 goto error_ret;
367 }
368 ret = iio_scan_mask_query(indio_dev, buffer, this_attr->address);
369 if (ret < 0)
370 goto error_ret;
371 if (!state && ret) {
372 ret = iio_scan_mask_clear(buffer, this_attr->address);
373 if (ret)
374 goto error_ret;
375 } else if (state && !ret) {
376 ret = iio_scan_mask_set(indio_dev, buffer, this_attr->address);
377 if (ret)
378 goto error_ret;
379 }
380
381 error_ret:
382 mutex_unlock(&indio_dev->mlock);
383
384 return ret < 0 ? ret : len;
385
386 }
387
388 static ssize_t iio_scan_el_ts_show(struct device *dev,
389 struct device_attribute *attr,
390 char *buf)
391 {
392 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
393 return sprintf(buf, "%d\n", indio_dev->buffer->scan_timestamp);
394 }
395
396 static ssize_t iio_scan_el_ts_store(struct device *dev,
397 struct device_attribute *attr,
398 const char *buf,
399 size_t len)
400 {
401 int ret;
402 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
403 bool state;
404
405 ret = strtobool(buf, &state);
406 if (ret < 0)
407 return ret;
408
409 mutex_lock(&indio_dev->mlock);
410 if (iio_buffer_is_active(indio_dev->buffer)) {
411 ret = -EBUSY;
412 goto error_ret;
413 }
414 indio_dev->buffer->scan_timestamp = state;
415 error_ret:
416 mutex_unlock(&indio_dev->mlock);
417
418 return ret ? ret : len;
419 }
420
421 static int iio_buffer_add_channel_sysfs(struct iio_dev *indio_dev,
422 const struct iio_chan_spec *chan)
423 {
424 int ret, attrcount = 0;
425 struct iio_buffer *buffer = indio_dev->buffer;
426
427 ret = __iio_add_chan_devattr("index",
428 chan,
429 &iio_show_scan_index,
430 NULL,
431 0,
432 IIO_SEPARATE,
433 &indio_dev->dev,
434 &buffer->scan_el_dev_attr_list);
435 if (ret)
436 return ret;
437 attrcount++;
438 ret = __iio_add_chan_devattr("type",
439 chan,
440 &iio_show_fixed_type,
441 NULL,
442 0,
443 0,
444 &indio_dev->dev,
445 &buffer->scan_el_dev_attr_list);
446 if (ret)
447 return ret;
448 attrcount++;
449 if (chan->type != IIO_TIMESTAMP)
450 ret = __iio_add_chan_devattr("en",
451 chan,
452 &iio_scan_el_show,
453 &iio_scan_el_store,
454 chan->scan_index,
455 0,
456 &indio_dev->dev,
457 &buffer->scan_el_dev_attr_list);
458 else
459 ret = __iio_add_chan_devattr("en",
460 chan,
461 &iio_scan_el_ts_show,
462 &iio_scan_el_ts_store,
463 chan->scan_index,
464 0,
465 &indio_dev->dev,
466 &buffer->scan_el_dev_attr_list);
467 if (ret)
468 return ret;
469 attrcount++;
470 ret = attrcount;
471 return ret;
472 }
473
474 static ssize_t iio_buffer_read_length(struct device *dev,
475 struct device_attribute *attr,
476 char *buf)
477 {
478 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
479 struct iio_buffer *buffer = indio_dev->buffer;
480
481 return sprintf(buf, "%d\n", buffer->length);
482 }
483
484 static ssize_t iio_buffer_write_length(struct device *dev,
485 struct device_attribute *attr,
486 const char *buf, size_t len)
487 {
488 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
489 struct iio_buffer *buffer = indio_dev->buffer;
490 unsigned int val;
491 int ret;
492
493 ret = kstrtouint(buf, 10, &val);
494 if (ret)
495 return ret;
496
497 if (val == buffer->length)
498 return len;
499
500 mutex_lock(&indio_dev->mlock);
501 if (iio_buffer_is_active(indio_dev->buffer)) {
502 ret = -EBUSY;
503 } else {
504 buffer->access->set_length(buffer, val);
505 ret = 0;
506 }
507 if (ret)
508 goto out;
509 if (buffer->length && buffer->length < buffer->watermark)
510 buffer->watermark = buffer->length;
511 out:
512 mutex_unlock(&indio_dev->mlock);
513
514 return ret ? ret : len;
515 }
516
517 static ssize_t iio_buffer_show_enable(struct device *dev,
518 struct device_attribute *attr,
519 char *buf)
520 {
521 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
522 return sprintf(buf, "%d\n", iio_buffer_is_active(indio_dev->buffer));
523 }
524
525 static int iio_compute_scan_bytes(struct iio_dev *indio_dev,
526 const unsigned long *mask, bool timestamp)
527 {
528 const struct iio_chan_spec *ch;
529 unsigned bytes = 0;
530 int length, i;
531
532 /* How much space will the demuxed element take? */
533 for_each_set_bit(i, mask,
534 indio_dev->masklength) {
535 ch = iio_find_channel_from_si(indio_dev, i);
536 if (ch->scan_type.repeat > 1)
537 length = ch->scan_type.storagebits / 8 *
538 ch->scan_type.repeat;
539 else
540 length = ch->scan_type.storagebits / 8;
541 bytes = ALIGN(bytes, length);
542 bytes += length;
543 }
544 if (timestamp) {
545 ch = iio_find_channel_from_si(indio_dev,
546 indio_dev->scan_index_timestamp);
547 if (ch->scan_type.repeat > 1)
548 length = ch->scan_type.storagebits / 8 *
549 ch->scan_type.repeat;
550 else
551 length = ch->scan_type.storagebits / 8;
552 bytes = ALIGN(bytes, length);
553 bytes += length;
554 }
555 return bytes;
556 }
557
558 static void iio_buffer_activate(struct iio_dev *indio_dev,
559 struct iio_buffer *buffer)
560 {
561 iio_buffer_get(buffer);
562 list_add(&buffer->buffer_list, &indio_dev->buffer_list);
563 }
564
565 static void iio_buffer_deactivate(struct iio_buffer *buffer)
566 {
567 list_del_init(&buffer->buffer_list);
568 wake_up_interruptible(&buffer->pollq);
569 iio_buffer_put(buffer);
570 }
571
572 static void iio_buffer_deactivate_all(struct iio_dev *indio_dev)
573 {
574 struct iio_buffer *buffer, *_buffer;
575
576 list_for_each_entry_safe(buffer, _buffer,
577 &indio_dev->buffer_list, buffer_list)
578 iio_buffer_deactivate(buffer);
579 }
580
581 static void iio_buffer_update_bytes_per_datum(struct iio_dev *indio_dev,
582 struct iio_buffer *buffer)
583 {
584 unsigned int bytes;
585
586 if (!buffer->access->set_bytes_per_datum)
587 return;
588
589 bytes = iio_compute_scan_bytes(indio_dev, buffer->scan_mask,
590 buffer->scan_timestamp);
591
592 buffer->access->set_bytes_per_datum(buffer, bytes);
593 }
594
595 static int iio_buffer_request_update(struct iio_dev *indio_dev,
596 struct iio_buffer *buffer)
597 {
598 int ret;
599
600 iio_buffer_update_bytes_per_datum(indio_dev, buffer);
601 if (buffer->access->request_update) {
602 ret = buffer->access->request_update(buffer);
603 if (ret) {
604 dev_dbg(&indio_dev->dev,
605 "Buffer not started: buffer parameter update failed (%d)\n",
606 ret);
607 return ret;
608 }
609 }
610
611 return 0;
612 }
613
614 static void iio_free_scan_mask(struct iio_dev *indio_dev,
615 const unsigned long *mask)
616 {
617 /* If the mask is dynamically allocated free it, otherwise do nothing */
618 if (!indio_dev->available_scan_masks)
619 kfree(mask);
620 }
621
622 struct iio_device_config {
623 unsigned int mode;
624 const unsigned long *scan_mask;
625 unsigned int scan_bytes;
626 bool scan_timestamp;
627 };
628
629 static int iio_verify_update(struct iio_dev *indio_dev,
630 struct iio_buffer *insert_buffer, struct iio_buffer *remove_buffer,
631 struct iio_device_config *config)
632 {
633 unsigned long *compound_mask;
634 const unsigned long *scan_mask;
635 bool strict_scanmask = false;
636 struct iio_buffer *buffer;
637 bool scan_timestamp;
638 unsigned int modes;
639
640 memset(config, 0, sizeof(*config));
641
642 /*
643 * If there is just one buffer and we are removing it there is nothing
644 * to verify.
645 */
646 if (remove_buffer && !insert_buffer &&
647 list_is_singular(&indio_dev->buffer_list))
648 return 0;
649
650 modes = indio_dev->modes;
651
652 list_for_each_entry(buffer, &indio_dev->buffer_list, buffer_list) {
653 if (buffer == remove_buffer)
654 continue;
655 modes &= buffer->access->modes;
656 }
657
658 if (insert_buffer)
659 modes &= insert_buffer->access->modes;
660
661 /* Definitely possible for devices to support both of these. */
662 if ((modes & INDIO_BUFFER_TRIGGERED) && indio_dev->trig) {
663 config->mode = INDIO_BUFFER_TRIGGERED;
664 } else if (modes & INDIO_BUFFER_HARDWARE) {
665 /*
666 * Keep things simple for now and only allow a single buffer to
667 * be connected in hardware mode.
668 */
669 if (insert_buffer && !list_empty(&indio_dev->buffer_list))
670 return -EINVAL;
671 config->mode = INDIO_BUFFER_HARDWARE;
672 strict_scanmask = true;
673 } else if (modes & INDIO_BUFFER_SOFTWARE) {
674 config->mode = INDIO_BUFFER_SOFTWARE;
675 } else {
676 /* Can only occur on first buffer */
677 if (indio_dev->modes & INDIO_BUFFER_TRIGGERED)
678 dev_dbg(&indio_dev->dev, "Buffer not started: no trigger\n");
679 return -EINVAL;
680 }
681
682 /* What scan mask do we actually have? */
683 compound_mask = kcalloc(BITS_TO_LONGS(indio_dev->masklength),
684 sizeof(long), GFP_KERNEL);
685 if (compound_mask == NULL)
686 return -ENOMEM;
687
688 scan_timestamp = false;
689
690 list_for_each_entry(buffer, &indio_dev->buffer_list, buffer_list) {
691 if (buffer == remove_buffer)
692 continue;
693 bitmap_or(compound_mask, compound_mask, buffer->scan_mask,
694 indio_dev->masklength);
695 scan_timestamp |= buffer->scan_timestamp;
696 }
697
698 if (insert_buffer) {
699 bitmap_or(compound_mask, compound_mask,
700 insert_buffer->scan_mask, indio_dev->masklength);
701 scan_timestamp |= insert_buffer->scan_timestamp;
702 }
703
704 if (indio_dev->available_scan_masks) {
705 scan_mask = iio_scan_mask_match(indio_dev->available_scan_masks,
706 indio_dev->masklength,
707 compound_mask,
708 strict_scanmask);
709 kfree(compound_mask);
710 if (scan_mask == NULL)
711 return -EINVAL;
712 } else {
713 scan_mask = compound_mask;
714 }
715
716 config->scan_bytes = iio_compute_scan_bytes(indio_dev,
717 scan_mask, scan_timestamp);
718 config->scan_mask = scan_mask;
719 config->scan_timestamp = scan_timestamp;
720
721 return 0;
722 }
723
724 static int iio_enable_buffers(struct iio_dev *indio_dev,
725 struct iio_device_config *config)
726 {
727 int ret;
728
729 indio_dev->active_scan_mask = config->scan_mask;
730 indio_dev->scan_timestamp = config->scan_timestamp;
731 indio_dev->scan_bytes = config->scan_bytes;
732
733 iio_update_demux(indio_dev);
734
735 /* Wind up again */
736 if (indio_dev->setup_ops->preenable) {
737 ret = indio_dev->setup_ops->preenable(indio_dev);
738 if (ret) {
739 dev_dbg(&indio_dev->dev,
740 "Buffer not started: buffer preenable failed (%d)\n", ret);
741 goto err_undo_config;
742 }
743 }
744
745 if (indio_dev->info->update_scan_mode) {
746 ret = indio_dev->info
747 ->update_scan_mode(indio_dev,
748 indio_dev->active_scan_mask);
749 if (ret < 0) {
750 dev_dbg(&indio_dev->dev,
751 "Buffer not started: update scan mode failed (%d)\n",
752 ret);
753 goto err_run_postdisable;
754 }
755 }
756
757 indio_dev->currentmode = config->mode;
758
759 if (indio_dev->setup_ops->postenable) {
760 ret = indio_dev->setup_ops->postenable(indio_dev);
761 if (ret) {
762 dev_dbg(&indio_dev->dev,
763 "Buffer not started: postenable failed (%d)\n", ret);
764 goto err_run_postdisable;
765 }
766 }
767
768 return 0;
769
770 err_run_postdisable:
771 indio_dev->currentmode = INDIO_DIRECT_MODE;
772 if (indio_dev->setup_ops->postdisable)
773 indio_dev->setup_ops->postdisable(indio_dev);
774 err_undo_config:
775 indio_dev->active_scan_mask = NULL;
776
777 return ret;
778 }
779
780 static int iio_disable_buffers(struct iio_dev *indio_dev)
781 {
782 int ret = 0;
783 int ret2;
784
785 /* Wind down existing buffers - iff there are any */
786 if (list_empty(&indio_dev->buffer_list))
787 return 0;
788
789 /*
790 * If things go wrong at some step in disable we still need to continue
791 * to perform the other steps, otherwise we leave the device in a
792 * inconsistent state. We return the error code for the first error we
793 * encountered.
794 */
795
796 if (indio_dev->setup_ops->predisable) {
797 ret2 = indio_dev->setup_ops->predisable(indio_dev);
798 if (ret2 && !ret)
799 ret = ret2;
800 }
801
802 indio_dev->currentmode = INDIO_DIRECT_MODE;
803
804 if (indio_dev->setup_ops->postdisable) {
805 ret2 = indio_dev->setup_ops->postdisable(indio_dev);
806 if (ret2 && !ret)
807 ret = ret2;
808 }
809
810 iio_free_scan_mask(indio_dev, indio_dev->active_scan_mask);
811 indio_dev->active_scan_mask = NULL;
812
813 return ret;
814 }
815
816 static int __iio_update_buffers(struct iio_dev *indio_dev,
817 struct iio_buffer *insert_buffer,
818 struct iio_buffer *remove_buffer)
819 {
820 struct iio_device_config new_config;
821 int ret;
822
823 ret = iio_verify_update(indio_dev, insert_buffer, remove_buffer,
824 &new_config);
825 if (ret)
826 return ret;
827
828 if (insert_buffer) {
829 ret = iio_buffer_request_update(indio_dev, insert_buffer);
830 if (ret)
831 goto err_free_config;
832 }
833
834 ret = iio_disable_buffers(indio_dev);
835 if (ret)
836 goto err_deactivate_all;
837
838 if (remove_buffer)
839 iio_buffer_deactivate(remove_buffer);
840 if (insert_buffer)
841 iio_buffer_activate(indio_dev, insert_buffer);
842
843 /* If no buffers in list, we are done */
844 if (list_empty(&indio_dev->buffer_list))
845 return 0;
846
847 ret = iio_enable_buffers(indio_dev, &new_config);
848 if (ret)
849 goto err_deactivate_all;
850
851 return 0;
852
853 err_deactivate_all:
854 /*
855 * We've already verified that the config is valid earlier. If things go
856 * wrong in either enable or disable the most likely reason is an IO
857 * error from the device. In this case there is no good recovery
858 * strategy. Just make sure to disable everything and leave the device
859 * in a sane state. With a bit of luck the device might come back to
860 * life again later and userspace can try again.
861 */
862 iio_buffer_deactivate_all(indio_dev);
863
864 err_free_config:
865 iio_free_scan_mask(indio_dev, new_config.scan_mask);
866 return ret;
867 }
868
869 int iio_update_buffers(struct iio_dev *indio_dev,
870 struct iio_buffer *insert_buffer,
871 struct iio_buffer *remove_buffer)
872 {
873 int ret;
874
875 if (insert_buffer == remove_buffer)
876 return 0;
877
878 mutex_lock(&indio_dev->info_exist_lock);
879 mutex_lock(&indio_dev->mlock);
880
881 if (insert_buffer && iio_buffer_is_active(insert_buffer))
882 insert_buffer = NULL;
883
884 if (remove_buffer && !iio_buffer_is_active(remove_buffer))
885 remove_buffer = NULL;
886
887 if (!insert_buffer && !remove_buffer) {
888 ret = 0;
889 goto out_unlock;
890 }
891
892 if (indio_dev->info == NULL) {
893 ret = -ENODEV;
894 goto out_unlock;
895 }
896
897 ret = __iio_update_buffers(indio_dev, insert_buffer, remove_buffer);
898
899 out_unlock:
900 mutex_unlock(&indio_dev->mlock);
901 mutex_unlock(&indio_dev->info_exist_lock);
902
903 return ret;
904 }
905 EXPORT_SYMBOL_GPL(iio_update_buffers);
906
907 void iio_disable_all_buffers(struct iio_dev *indio_dev)
908 {
909 iio_disable_buffers(indio_dev);
910 iio_buffer_deactivate_all(indio_dev);
911 }
912
913 static ssize_t iio_buffer_store_enable(struct device *dev,
914 struct device_attribute *attr,
915 const char *buf,
916 size_t len)
917 {
918 int ret;
919 bool requested_state;
920 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
921 bool inlist;
922
923 ret = strtobool(buf, &requested_state);
924 if (ret < 0)
925 return ret;
926
927 mutex_lock(&indio_dev->mlock);
928
929 /* Find out if it is in the list */
930 inlist = iio_buffer_is_active(indio_dev->buffer);
931 /* Already in desired state */
932 if (inlist == requested_state)
933 goto done;
934
935 if (requested_state)
936 ret = __iio_update_buffers(indio_dev,
937 indio_dev->buffer, NULL);
938 else
939 ret = __iio_update_buffers(indio_dev,
940 NULL, indio_dev->buffer);
941
942 done:
943 mutex_unlock(&indio_dev->mlock);
944 return (ret < 0) ? ret : len;
945 }
946
947 static const char * const iio_scan_elements_group_name = "scan_elements";
948
949 static ssize_t iio_buffer_show_watermark(struct device *dev,
950 struct device_attribute *attr,
951 char *buf)
952 {
953 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
954 struct iio_buffer *buffer = indio_dev->buffer;
955
956 return sprintf(buf, "%u\n", buffer->watermark);
957 }
958
959 static ssize_t iio_buffer_store_watermark(struct device *dev,
960 struct device_attribute *attr,
961 const char *buf,
962 size_t len)
963 {
964 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
965 struct iio_buffer *buffer = indio_dev->buffer;
966 unsigned int val;
967 int ret;
968
969 ret = kstrtouint(buf, 10, &val);
970 if (ret)
971 return ret;
972 if (!val)
973 return -EINVAL;
974
975 mutex_lock(&indio_dev->mlock);
976
977 if (val > buffer->length) {
978 ret = -EINVAL;
979 goto out;
980 }
981
982 if (iio_buffer_is_active(indio_dev->buffer)) {
983 ret = -EBUSY;
984 goto out;
985 }
986
987 buffer->watermark = val;
988
989 if (indio_dev->info->hwfifo_set_watermark)
990 indio_dev->info->hwfifo_set_watermark(indio_dev, val);
991 out:
992 mutex_unlock(&indio_dev->mlock);
993
994 return ret ? ret : len;
995 }
996
997 static DEVICE_ATTR(length, S_IRUGO | S_IWUSR, iio_buffer_read_length,
998 iio_buffer_write_length);
999 static struct device_attribute dev_attr_length_ro = __ATTR(length,
1000 S_IRUGO, iio_buffer_read_length, NULL);
1001 static DEVICE_ATTR(enable, S_IRUGO | S_IWUSR,
1002 iio_buffer_show_enable, iio_buffer_store_enable);
1003 static DEVICE_ATTR(watermark, S_IRUGO | S_IWUSR,
1004 iio_buffer_show_watermark, iio_buffer_store_watermark);
1005
1006 static struct attribute *iio_buffer_attrs[] = {
1007 &dev_attr_length.attr,
1008 &dev_attr_enable.attr,
1009 &dev_attr_watermark.attr,
1010 };
1011
1012 int iio_buffer_alloc_sysfs_and_mask(struct iio_dev *indio_dev)
1013 {
1014 struct iio_dev_attr *p;
1015 struct attribute **attr;
1016 struct iio_buffer *buffer = indio_dev->buffer;
1017 int ret, i, attrn, attrcount, attrcount_orig = 0;
1018 const struct iio_chan_spec *channels;
1019
1020 channels = indio_dev->channels;
1021 if (channels) {
1022 int ml = indio_dev->masklength;
1023
1024 for (i = 0; i < indio_dev->num_channels; i++)
1025 ml = max(ml, channels[i].scan_index + 1);
1026 indio_dev->masklength = ml;
1027 }
1028
1029 if (!buffer)
1030 return 0;
1031
1032 attrcount = 0;
1033 if (buffer->attrs) {
1034 while (buffer->attrs[attrcount] != NULL)
1035 attrcount++;
1036 }
1037
1038 attr = kcalloc(attrcount + ARRAY_SIZE(iio_buffer_attrs) + 1,
1039 sizeof(struct attribute *), GFP_KERNEL);
1040 if (!attr)
1041 return -ENOMEM;
1042
1043 memcpy(attr, iio_buffer_attrs, sizeof(iio_buffer_attrs));
1044 if (!buffer->access->set_length)
1045 attr[0] = &dev_attr_length_ro.attr;
1046
1047 if (buffer->attrs)
1048 memcpy(&attr[ARRAY_SIZE(iio_buffer_attrs)], buffer->attrs,
1049 sizeof(struct attribute *) * attrcount);
1050
1051 attr[attrcount + ARRAY_SIZE(iio_buffer_attrs)] = NULL;
1052
1053 buffer->buffer_group.name = "buffer";
1054 buffer->buffer_group.attrs = attr;
1055
1056 indio_dev->groups[indio_dev->groupcounter++] = &buffer->buffer_group;
1057
1058 if (buffer->scan_el_attrs != NULL) {
1059 attr = buffer->scan_el_attrs->attrs;
1060 while (*attr++ != NULL)
1061 attrcount_orig++;
1062 }
1063 attrcount = attrcount_orig;
1064 INIT_LIST_HEAD(&buffer->scan_el_dev_attr_list);
1065 channels = indio_dev->channels;
1066 if (channels) {
1067 /* new magic */
1068 for (i = 0; i < indio_dev->num_channels; i++) {
1069 if (channels[i].scan_index < 0)
1070 continue;
1071
1072 ret = iio_buffer_add_channel_sysfs(indio_dev,
1073 &channels[i]);
1074 if (ret < 0)
1075 goto error_cleanup_dynamic;
1076 attrcount += ret;
1077 if (channels[i].type == IIO_TIMESTAMP)
1078 indio_dev->scan_index_timestamp =
1079 channels[i].scan_index;
1080 }
1081 if (indio_dev->masklength && buffer->scan_mask == NULL) {
1082 buffer->scan_mask = kcalloc(BITS_TO_LONGS(indio_dev->masklength),
1083 sizeof(*buffer->scan_mask),
1084 GFP_KERNEL);
1085 if (buffer->scan_mask == NULL) {
1086 ret = -ENOMEM;
1087 goto error_cleanup_dynamic;
1088 }
1089 }
1090 }
1091
1092 buffer->scan_el_group.name = iio_scan_elements_group_name;
1093
1094 buffer->scan_el_group.attrs = kcalloc(attrcount + 1,
1095 sizeof(buffer->scan_el_group.attrs[0]),
1096 GFP_KERNEL);
1097 if (buffer->scan_el_group.attrs == NULL) {
1098 ret = -ENOMEM;
1099 goto error_free_scan_mask;
1100 }
1101 if (buffer->scan_el_attrs)
1102 memcpy(buffer->scan_el_group.attrs, buffer->scan_el_attrs,
1103 sizeof(buffer->scan_el_group.attrs[0])*attrcount_orig);
1104 attrn = attrcount_orig;
1105
1106 list_for_each_entry(p, &buffer->scan_el_dev_attr_list, l)
1107 buffer->scan_el_group.attrs[attrn++] = &p->dev_attr.attr;
1108 indio_dev->groups[indio_dev->groupcounter++] = &buffer->scan_el_group;
1109
1110 return 0;
1111
1112 error_free_scan_mask:
1113 kfree(buffer->scan_mask);
1114 error_cleanup_dynamic:
1115 iio_free_chan_devattr_list(&buffer->scan_el_dev_attr_list);
1116 kfree(indio_dev->buffer->buffer_group.attrs);
1117
1118 return ret;
1119 }
1120
1121 void iio_buffer_free_sysfs_and_mask(struct iio_dev *indio_dev)
1122 {
1123 if (!indio_dev->buffer)
1124 return;
1125
1126 kfree(indio_dev->buffer->scan_mask);
1127 kfree(indio_dev->buffer->buffer_group.attrs);
1128 kfree(indio_dev->buffer->scan_el_group.attrs);
1129 iio_free_chan_devattr_list(&indio_dev->buffer->scan_el_dev_attr_list);
1130 }
1131
1132 /**
1133 * iio_validate_scan_mask_onehot() - Validates that exactly one channel is selected
1134 * @indio_dev: the iio device
1135 * @mask: scan mask to be checked
1136 *
1137 * Return true if exactly one bit is set in the scan mask, false otherwise. It
1138 * can be used for devices where only one channel can be active for sampling at
1139 * a time.
1140 */
1141 bool iio_validate_scan_mask_onehot(struct iio_dev *indio_dev,
1142 const unsigned long *mask)
1143 {
1144 return bitmap_weight(mask, indio_dev->masklength) == 1;
1145 }
1146 EXPORT_SYMBOL_GPL(iio_validate_scan_mask_onehot);
1147
1148 int iio_scan_mask_query(struct iio_dev *indio_dev,
1149 struct iio_buffer *buffer, int bit)
1150 {
1151 if (bit > indio_dev->masklength)
1152 return -EINVAL;
1153
1154 if (!buffer->scan_mask)
1155 return 0;
1156
1157 /* Ensure return value is 0 or 1. */
1158 return !!test_bit(bit, buffer->scan_mask);
1159 };
1160 EXPORT_SYMBOL_GPL(iio_scan_mask_query);
1161
1162 /**
1163 * struct iio_demux_table - table describing demux memcpy ops
1164 * @from: index to copy from
1165 * @to: index to copy to
1166 * @length: how many bytes to copy
1167 * @l: list head used for management
1168 */
1169 struct iio_demux_table {
1170 unsigned from;
1171 unsigned to;
1172 unsigned length;
1173 struct list_head l;
1174 };
1175
1176 static const void *iio_demux(struct iio_buffer *buffer,
1177 const void *datain)
1178 {
1179 struct iio_demux_table *t;
1180
1181 if (list_empty(&buffer->demux_list))
1182 return datain;
1183 list_for_each_entry(t, &buffer->demux_list, l)
1184 memcpy(buffer->demux_bounce + t->to,
1185 datain + t->from, t->length);
1186
1187 return buffer->demux_bounce;
1188 }
1189
1190 static int iio_push_to_buffer(struct iio_buffer *buffer, const void *data)
1191 {
1192 const void *dataout = iio_demux(buffer, data);
1193 int ret;
1194
1195 ret = buffer->access->store_to(buffer, dataout);
1196 if (ret)
1197 return ret;
1198
1199 /*
1200 * We can't just test for watermark to decide if we wake the poll queue
1201 * because read may request less samples than the watermark.
1202 */
1203 wake_up_interruptible_poll(&buffer->pollq, POLLIN | POLLRDNORM);
1204 return 0;
1205 }
1206
1207 static void iio_buffer_demux_free(struct iio_buffer *buffer)
1208 {
1209 struct iio_demux_table *p, *q;
1210 list_for_each_entry_safe(p, q, &buffer->demux_list, l) {
1211 list_del(&p->l);
1212 kfree(p);
1213 }
1214 }
1215
1216
1217 int iio_push_to_buffers(struct iio_dev *indio_dev, const void *data)
1218 {
1219 int ret;
1220 struct iio_buffer *buf;
1221
1222 list_for_each_entry(buf, &indio_dev->buffer_list, buffer_list) {
1223 ret = iio_push_to_buffer(buf, data);
1224 if (ret < 0)
1225 return ret;
1226 }
1227
1228 return 0;
1229 }
1230 EXPORT_SYMBOL_GPL(iio_push_to_buffers);
1231
1232 static int iio_buffer_add_demux(struct iio_buffer *buffer,
1233 struct iio_demux_table **p, unsigned int in_loc, unsigned int out_loc,
1234 unsigned int length)
1235 {
1236
1237 if (*p && (*p)->from + (*p)->length == in_loc &&
1238 (*p)->to + (*p)->length == out_loc) {
1239 (*p)->length += length;
1240 } else {
1241 *p = kmalloc(sizeof(**p), GFP_KERNEL);
1242 if (*p == NULL)
1243 return -ENOMEM;
1244 (*p)->from = in_loc;
1245 (*p)->to = out_loc;
1246 (*p)->length = length;
1247 list_add_tail(&(*p)->l, &buffer->demux_list);
1248 }
1249
1250 return 0;
1251 }
1252
1253 static int iio_buffer_update_demux(struct iio_dev *indio_dev,
1254 struct iio_buffer *buffer)
1255 {
1256 const struct iio_chan_spec *ch;
1257 int ret, in_ind = -1, out_ind, length;
1258 unsigned in_loc = 0, out_loc = 0;
1259 struct iio_demux_table *p = NULL;
1260
1261 /* Clear out any old demux */
1262 iio_buffer_demux_free(buffer);
1263 kfree(buffer->demux_bounce);
1264 buffer->demux_bounce = NULL;
1265
1266 /* First work out which scan mode we will actually have */
1267 if (bitmap_equal(indio_dev->active_scan_mask,
1268 buffer->scan_mask,
1269 indio_dev->masklength))
1270 return 0;
1271
1272 /* Now we have the two masks, work from least sig and build up sizes */
1273 for_each_set_bit(out_ind,
1274 buffer->scan_mask,
1275 indio_dev->masklength) {
1276 in_ind = find_next_bit(indio_dev->active_scan_mask,
1277 indio_dev->masklength,
1278 in_ind + 1);
1279 while (in_ind != out_ind) {
1280 in_ind = find_next_bit(indio_dev->active_scan_mask,
1281 indio_dev->masklength,
1282 in_ind + 1);
1283 ch = iio_find_channel_from_si(indio_dev, in_ind);
1284 if (ch->scan_type.repeat > 1)
1285 length = ch->scan_type.storagebits / 8 *
1286 ch->scan_type.repeat;
1287 else
1288 length = ch->scan_type.storagebits / 8;
1289 /* Make sure we are aligned */
1290 in_loc = roundup(in_loc, length) + length;
1291 }
1292 ch = iio_find_channel_from_si(indio_dev, in_ind);
1293 if (ch->scan_type.repeat > 1)
1294 length = ch->scan_type.storagebits / 8 *
1295 ch->scan_type.repeat;
1296 else
1297 length = ch->scan_type.storagebits / 8;
1298 out_loc = roundup(out_loc, length);
1299 in_loc = roundup(in_loc, length);
1300 ret = iio_buffer_add_demux(buffer, &p, in_loc, out_loc, length);
1301 if (ret)
1302 goto error_clear_mux_table;
1303 out_loc += length;
1304 in_loc += length;
1305 }
1306 /* Relies on scan_timestamp being last */
1307 if (buffer->scan_timestamp) {
1308 ch = iio_find_channel_from_si(indio_dev,
1309 indio_dev->scan_index_timestamp);
1310 if (ch->scan_type.repeat > 1)
1311 length = ch->scan_type.storagebits / 8 *
1312 ch->scan_type.repeat;
1313 else
1314 length = ch->scan_type.storagebits / 8;
1315 out_loc = roundup(out_loc, length);
1316 in_loc = roundup(in_loc, length);
1317 ret = iio_buffer_add_demux(buffer, &p, in_loc, out_loc, length);
1318 if (ret)
1319 goto error_clear_mux_table;
1320 out_loc += length;
1321 in_loc += length;
1322 }
1323 buffer->demux_bounce = kzalloc(out_loc, GFP_KERNEL);
1324 if (buffer->demux_bounce == NULL) {
1325 ret = -ENOMEM;
1326 goto error_clear_mux_table;
1327 }
1328 return 0;
1329
1330 error_clear_mux_table:
1331 iio_buffer_demux_free(buffer);
1332
1333 return ret;
1334 }
1335
1336 int iio_update_demux(struct iio_dev *indio_dev)
1337 {
1338 struct iio_buffer *buffer;
1339 int ret;
1340
1341 list_for_each_entry(buffer, &indio_dev->buffer_list, buffer_list) {
1342 ret = iio_buffer_update_demux(indio_dev, buffer);
1343 if (ret < 0)
1344 goto error_clear_mux_table;
1345 }
1346 return 0;
1347
1348 error_clear_mux_table:
1349 list_for_each_entry(buffer, &indio_dev->buffer_list, buffer_list)
1350 iio_buffer_demux_free(buffer);
1351
1352 return ret;
1353 }
1354 EXPORT_SYMBOL_GPL(iio_update_demux);
1355
1356 /**
1357 * iio_buffer_release() - Free a buffer's resources
1358 * @ref: Pointer to the kref embedded in the iio_buffer struct
1359 *
1360 * This function is called when the last reference to the buffer has been
1361 * dropped. It will typically free all resources allocated by the buffer. Do not
1362 * call this function manually, always use iio_buffer_put() when done using a
1363 * buffer.
1364 */
1365 static void iio_buffer_release(struct kref *ref)
1366 {
1367 struct iio_buffer *buffer = container_of(ref, struct iio_buffer, ref);
1368
1369 buffer->access->release(buffer);
1370 }
1371
1372 /**
1373 * iio_buffer_get() - Grab a reference to the buffer
1374 * @buffer: The buffer to grab a reference for, may be NULL
1375 *
1376 * Returns the pointer to the buffer that was passed into the function.
1377 */
1378 struct iio_buffer *iio_buffer_get(struct iio_buffer *buffer)
1379 {
1380 if (buffer)
1381 kref_get(&buffer->ref);
1382
1383 return buffer;
1384 }
1385 EXPORT_SYMBOL_GPL(iio_buffer_get);
1386
1387 /**
1388 * iio_buffer_put() - Release the reference to the buffer
1389 * @buffer: The buffer to release the reference for, may be NULL
1390 */
1391 void iio_buffer_put(struct iio_buffer *buffer)
1392 {
1393 if (buffer)
1394 kref_put(&buffer->ref, iio_buffer_release);
1395 }
1396 EXPORT_SYMBOL_GPL(iio_buffer_put);
Linux with added FPC-III support