1 /* The industrial I/O core
3 * Copyright (c) 2008 Jonathan Cameron
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.
9 * Handling of buffer allocation / resizing.
12 * Things to look at here.
13 * - Better memory allocation techniques?
14 * - Alternative access techniques?
16 #include <linux/kernel.h>
17 #include <linux/export.h>
18 #include <linux/device.h>
20 #include <linux/cdev.h>
21 #include <linux/slab.h>
22 #include <linux/poll.h>
23 #include <linux/sched/signal.h>
25 #include <linux/iio/iio.h>
27 #include <linux/iio/sysfs.h>
28 #include <linux/iio/buffer.h>
29 #include <linux/iio/buffer_impl.h>
31 static const char * const iio_endian_prefix[] = {
36 static bool iio_buffer_is_active(struct iio_buffer *buf)
38 return !list_empty(&buf->buffer_list);
41 static size_t iio_buffer_data_available(struct iio_buffer *buf)
43 return buf->access->data_available(buf);
46 static int iio_buffer_flush_hwfifo(struct iio_dev *indio_dev,
47 struct iio_buffer *buf, size_t required)
49 if (!indio_dev->info->hwfifo_flush_to_buffer)
52 return indio_dev->info->hwfifo_flush_to_buffer(indio_dev, required);
55 static bool iio_buffer_ready(struct iio_dev *indio_dev, struct iio_buffer *buf,
56 size_t to_wait, int to_flush)
61 /* wakeup if the device was unregistered */
65 /* drain the buffer if it was disabled */
66 if (!iio_buffer_is_active(buf)) {
67 to_wait = min_t(size_t, to_wait, 1);
71 avail = iio_buffer_data_available(buf);
73 if (avail >= to_wait) {
74 /* force a flush for non-blocking reads */
75 if (!to_wait && avail < to_flush)
76 iio_buffer_flush_hwfifo(indio_dev, buf,
82 flushed = iio_buffer_flush_hwfifo(indio_dev, buf,
87 if (avail + flushed >= to_wait)
94 * iio_buffer_read_first_n_outer() - chrdev read for buffer access
95 * @filp: File structure pointer for the char device
96 * @buf: Destination buffer for iio buffer read
97 * @n: First n bytes to read
98 * @f_ps: Long offset provided by the user as a seek position
100 * This function relies on all buffer implementations having an
101 * iio_buffer as their first element.
103 * Return: negative values corresponding to error codes or ret != 0
104 * for ending the reading activity
106 ssize_t iio_buffer_read_first_n_outer(struct file *filp, char __user *buf,
107 size_t n, loff_t *f_ps)
109 struct iio_dev *indio_dev = filp->private_data;
110 struct iio_buffer *rb = indio_dev->buffer;
111 DEFINE_WAIT_FUNC(wait, woken_wake_function);
116 if (!indio_dev->info)
119 if (!rb || !rb->access->read_first_n)
122 datum_size = rb->bytes_per_datum;
125 * If datum_size is 0 there will never be anything to read from the
126 * buffer, so signal end of file now.
131 if (filp->f_flags & O_NONBLOCK)
134 to_wait = min_t(size_t, n / datum_size, rb->watermark);
136 add_wait_queue(&rb->pollq, &wait);
138 if (!indio_dev->info) {
143 if (!iio_buffer_ready(indio_dev, rb, to_wait, n / datum_size)) {
144 if (signal_pending(current)) {
149 wait_woken(&wait, TASK_INTERRUPTIBLE,
150 MAX_SCHEDULE_TIMEOUT);
154 ret = rb->access->read_first_n(rb, n, buf);
155 if (ret == 0 && (filp->f_flags & O_NONBLOCK))
158 remove_wait_queue(&rb->pollq, &wait);
164 * iio_buffer_poll() - poll the buffer to find out if it has data
165 * @filp: File structure pointer for device access
166 * @wait: Poll table structure pointer for which the driver adds
169 * Return: (EPOLLIN | EPOLLRDNORM) if data is available for reading
170 * or 0 for other cases
172 __poll_t iio_buffer_poll(struct file *filp,
173 struct poll_table_struct *wait)
175 struct iio_dev *indio_dev = filp->private_data;
176 struct iio_buffer *rb = indio_dev->buffer;
178 if (!indio_dev->info || rb == NULL)
181 poll_wait(filp, &rb->pollq, wait);
182 if (iio_buffer_ready(indio_dev, rb, rb->watermark, 0))
183 return EPOLLIN | EPOLLRDNORM;
188 * iio_buffer_wakeup_poll - Wakes up the buffer waitqueue
189 * @indio_dev: The IIO device
191 * Wakes up the event waitqueue used for poll(). Should usually
192 * be called when the device is unregistered.
194 void iio_buffer_wakeup_poll(struct iio_dev *indio_dev)
196 if (!indio_dev->buffer)
199 wake_up(&indio_dev->buffer->pollq);
202 void iio_buffer_init(struct iio_buffer *buffer)
204 INIT_LIST_HEAD(&buffer->demux_list);
205 INIT_LIST_HEAD(&buffer->buffer_list);
206 init_waitqueue_head(&buffer->pollq);
207 kref_init(&buffer->ref);
208 if (!buffer->watermark)
209 buffer->watermark = 1;
211 EXPORT_SYMBOL(iio_buffer_init);
214 * iio_buffer_set_attrs - Set buffer specific attributes
215 * @buffer: The buffer for which we are setting attributes
216 * @attrs: Pointer to a null terminated list of pointers to attributes
218 void iio_buffer_set_attrs(struct iio_buffer *buffer,
219 const struct attribute **attrs)
221 buffer->attrs = attrs;
223 EXPORT_SYMBOL_GPL(iio_buffer_set_attrs);
225 static ssize_t iio_show_scan_index(struct device *dev,
226 struct device_attribute *attr,
229 return sprintf(buf, "%u\n", to_iio_dev_attr(attr)->c->scan_index);
232 static ssize_t iio_show_fixed_type(struct device *dev,
233 struct device_attribute *attr,
236 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
237 u8 type = this_attr->c->scan_type.endianness;
239 if (type == IIO_CPU) {
240 #ifdef __LITTLE_ENDIAN
246 if (this_attr->c->scan_type.repeat > 1)
247 return sprintf(buf, "%s:%c%d/%dX%d>>%u\n",
248 iio_endian_prefix[type],
249 this_attr->c->scan_type.sign,
250 this_attr->c->scan_type.realbits,
251 this_attr->c->scan_type.storagebits,
252 this_attr->c->scan_type.repeat,
253 this_attr->c->scan_type.shift);
255 return sprintf(buf, "%s:%c%d/%d>>%u\n",
256 iio_endian_prefix[type],
257 this_attr->c->scan_type.sign,
258 this_attr->c->scan_type.realbits,
259 this_attr->c->scan_type.storagebits,
260 this_attr->c->scan_type.shift);
263 static ssize_t iio_scan_el_show(struct device *dev,
264 struct device_attribute *attr,
268 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
270 /* Ensure ret is 0 or 1. */
271 ret = !!test_bit(to_iio_dev_attr(attr)->address,
272 indio_dev->buffer->scan_mask);
274 return sprintf(buf, "%d\n", ret);
277 /* Note NULL used as error indicator as it doesn't make sense. */
278 static const unsigned long *iio_scan_mask_match(const unsigned long *av_masks,
279 unsigned int masklength,
280 const unsigned long *mask,
283 if (bitmap_empty(mask, masklength))
287 if (bitmap_equal(mask, av_masks, masklength))
290 if (bitmap_subset(mask, av_masks, masklength))
293 av_masks += BITS_TO_LONGS(masklength);
298 static bool iio_validate_scan_mask(struct iio_dev *indio_dev,
299 const unsigned long *mask)
301 if (!indio_dev->setup_ops->validate_scan_mask)
304 return indio_dev->setup_ops->validate_scan_mask(indio_dev, mask);
308 * iio_scan_mask_set() - set particular bit in the scan mask
309 * @indio_dev: the iio device
310 * @buffer: the buffer whose scan mask we are interested in
311 * @bit: the bit to be set.
313 * Note that at this point we have no way of knowing what other
314 * buffers might request, hence this code only verifies that the
315 * individual buffers request is plausible.
317 static int iio_scan_mask_set(struct iio_dev *indio_dev,
318 struct iio_buffer *buffer, int bit)
320 const unsigned long *mask;
321 unsigned long *trialmask;
323 trialmask = kcalloc(BITS_TO_LONGS(indio_dev->masklength),
324 sizeof(*trialmask), GFP_KERNEL);
325 if (trialmask == NULL)
327 if (!indio_dev->masklength) {
328 WARN(1, "Trying to set scanmask prior to registering buffer\n");
329 goto err_invalid_mask;
331 bitmap_copy(trialmask, buffer->scan_mask, indio_dev->masklength);
332 set_bit(bit, trialmask);
334 if (!iio_validate_scan_mask(indio_dev, trialmask))
335 goto err_invalid_mask;
337 if (indio_dev->available_scan_masks) {
338 mask = iio_scan_mask_match(indio_dev->available_scan_masks,
339 indio_dev->masklength,
342 goto err_invalid_mask;
344 bitmap_copy(buffer->scan_mask, trialmask, indio_dev->masklength);
355 static int iio_scan_mask_clear(struct iio_buffer *buffer, int bit)
357 clear_bit(bit, buffer->scan_mask);
361 static int iio_scan_mask_query(struct iio_dev *indio_dev,
362 struct iio_buffer *buffer, int bit)
364 if (bit > indio_dev->masklength)
367 if (!buffer->scan_mask)
370 /* Ensure return value is 0 or 1. */
371 return !!test_bit(bit, buffer->scan_mask);
374 static ssize_t iio_scan_el_store(struct device *dev,
375 struct device_attribute *attr,
381 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
382 struct iio_buffer *buffer = indio_dev->buffer;
383 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
385 ret = strtobool(buf, &state);
388 mutex_lock(&indio_dev->mlock);
389 if (iio_buffer_is_active(indio_dev->buffer)) {
393 ret = iio_scan_mask_query(indio_dev, buffer, this_attr->address);
397 ret = iio_scan_mask_clear(buffer, this_attr->address);
400 } else if (state && !ret) {
401 ret = iio_scan_mask_set(indio_dev, buffer, this_attr->address);
407 mutex_unlock(&indio_dev->mlock);
409 return ret < 0 ? ret : len;
413 static ssize_t iio_scan_el_ts_show(struct device *dev,
414 struct device_attribute *attr,
417 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
418 return sprintf(buf, "%d\n", indio_dev->buffer->scan_timestamp);
421 static ssize_t iio_scan_el_ts_store(struct device *dev,
422 struct device_attribute *attr,
427 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
430 ret = strtobool(buf, &state);
434 mutex_lock(&indio_dev->mlock);
435 if (iio_buffer_is_active(indio_dev->buffer)) {
439 indio_dev->buffer->scan_timestamp = state;
441 mutex_unlock(&indio_dev->mlock);
443 return ret ? ret : len;
446 static int iio_buffer_add_channel_sysfs(struct iio_dev *indio_dev,
447 const struct iio_chan_spec *chan)
449 int ret, attrcount = 0;
450 struct iio_buffer *buffer = indio_dev->buffer;
452 ret = __iio_add_chan_devattr("index",
454 &iio_show_scan_index,
459 &buffer->scan_el_dev_attr_list);
463 ret = __iio_add_chan_devattr("type",
465 &iio_show_fixed_type,
470 &buffer->scan_el_dev_attr_list);
474 if (chan->type != IIO_TIMESTAMP)
475 ret = __iio_add_chan_devattr("en",
482 &buffer->scan_el_dev_attr_list);
484 ret = __iio_add_chan_devattr("en",
486 &iio_scan_el_ts_show,
487 &iio_scan_el_ts_store,
491 &buffer->scan_el_dev_attr_list);
499 static ssize_t iio_buffer_read_length(struct device *dev,
500 struct device_attribute *attr,
503 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
504 struct iio_buffer *buffer = indio_dev->buffer;
506 return sprintf(buf, "%d\n", buffer->length);
509 static ssize_t iio_buffer_write_length(struct device *dev,
510 struct device_attribute *attr,
511 const char *buf, size_t len)
513 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
514 struct iio_buffer *buffer = indio_dev->buffer;
518 ret = kstrtouint(buf, 10, &val);
522 if (val == buffer->length)
525 mutex_lock(&indio_dev->mlock);
526 if (iio_buffer_is_active(indio_dev->buffer)) {
529 buffer->access->set_length(buffer, val);
534 if (buffer->length && buffer->length < buffer->watermark)
535 buffer->watermark = buffer->length;
537 mutex_unlock(&indio_dev->mlock);
539 return ret ? ret : len;
542 static ssize_t iio_buffer_show_enable(struct device *dev,
543 struct device_attribute *attr,
546 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
547 return sprintf(buf, "%d\n", iio_buffer_is_active(indio_dev->buffer));
550 static unsigned int iio_storage_bytes_for_si(struct iio_dev *indio_dev,
551 unsigned int scan_index)
553 const struct iio_chan_spec *ch;
556 ch = iio_find_channel_from_si(indio_dev, scan_index);
557 bytes = ch->scan_type.storagebits / 8;
558 if (ch->scan_type.repeat > 1)
559 bytes *= ch->scan_type.repeat;
563 static unsigned int iio_storage_bytes_for_timestamp(struct iio_dev *indio_dev)
565 return iio_storage_bytes_for_si(indio_dev,
566 indio_dev->scan_index_timestamp);
569 static int iio_compute_scan_bytes(struct iio_dev *indio_dev,
570 const unsigned long *mask, bool timestamp)
573 int length, i, largest = 0;
575 /* How much space will the demuxed element take? */
576 for_each_set_bit(i, mask,
577 indio_dev->masklength) {
578 length = iio_storage_bytes_for_si(indio_dev, i);
579 bytes = ALIGN(bytes, length);
581 largest = max(largest, length);
585 length = iio_storage_bytes_for_timestamp(indio_dev);
586 bytes = ALIGN(bytes, length);
588 largest = max(largest, length);
591 bytes = ALIGN(bytes, largest);
595 static void iio_buffer_activate(struct iio_dev *indio_dev,
596 struct iio_buffer *buffer)
598 iio_buffer_get(buffer);
599 list_add(&buffer->buffer_list, &indio_dev->buffer_list);
602 static void iio_buffer_deactivate(struct iio_buffer *buffer)
604 list_del_init(&buffer->buffer_list);
605 wake_up_interruptible(&buffer->pollq);
606 iio_buffer_put(buffer);
609 static void iio_buffer_deactivate_all(struct iio_dev *indio_dev)
611 struct iio_buffer *buffer, *_buffer;
613 list_for_each_entry_safe(buffer, _buffer,
614 &indio_dev->buffer_list, buffer_list)
615 iio_buffer_deactivate(buffer);
618 static int iio_buffer_enable(struct iio_buffer *buffer,
619 struct iio_dev *indio_dev)
621 if (!buffer->access->enable)
623 return buffer->access->enable(buffer, indio_dev);
626 static int iio_buffer_disable(struct iio_buffer *buffer,
627 struct iio_dev *indio_dev)
629 if (!buffer->access->disable)
631 return buffer->access->disable(buffer, indio_dev);
634 static void iio_buffer_update_bytes_per_datum(struct iio_dev *indio_dev,
635 struct iio_buffer *buffer)
639 if (!buffer->access->set_bytes_per_datum)
642 bytes = iio_compute_scan_bytes(indio_dev, buffer->scan_mask,
643 buffer->scan_timestamp);
645 buffer->access->set_bytes_per_datum(buffer, bytes);
648 static int iio_buffer_request_update(struct iio_dev *indio_dev,
649 struct iio_buffer *buffer)
653 iio_buffer_update_bytes_per_datum(indio_dev, buffer);
654 if (buffer->access->request_update) {
655 ret = buffer->access->request_update(buffer);
657 dev_dbg(&indio_dev->dev,
658 "Buffer not started: buffer parameter update failed (%d)\n",
667 static void iio_free_scan_mask(struct iio_dev *indio_dev,
668 const unsigned long *mask)
670 /* If the mask is dynamically allocated free it, otherwise do nothing */
671 if (!indio_dev->available_scan_masks)
675 struct iio_device_config {
677 unsigned int watermark;
678 const unsigned long *scan_mask;
679 unsigned int scan_bytes;
683 static int iio_verify_update(struct iio_dev *indio_dev,
684 struct iio_buffer *insert_buffer, struct iio_buffer *remove_buffer,
685 struct iio_device_config *config)
687 unsigned long *compound_mask;
688 const unsigned long *scan_mask;
689 bool strict_scanmask = false;
690 struct iio_buffer *buffer;
694 memset(config, 0, sizeof(*config));
695 config->watermark = ~0;
698 * If there is just one buffer and we are removing it there is nothing
701 if (remove_buffer && !insert_buffer &&
702 list_is_singular(&indio_dev->buffer_list))
705 modes = indio_dev->modes;
707 list_for_each_entry(buffer, &indio_dev->buffer_list, buffer_list) {
708 if (buffer == remove_buffer)
710 modes &= buffer->access->modes;
711 config->watermark = min(config->watermark, buffer->watermark);
715 modes &= insert_buffer->access->modes;
716 config->watermark = min(config->watermark,
717 insert_buffer->watermark);
720 /* Definitely possible for devices to support both of these. */
721 if ((modes & INDIO_BUFFER_TRIGGERED) && indio_dev->trig) {
722 config->mode = INDIO_BUFFER_TRIGGERED;
723 } else if (modes & INDIO_BUFFER_HARDWARE) {
725 * Keep things simple for now and only allow a single buffer to
726 * be connected in hardware mode.
728 if (insert_buffer && !list_empty(&indio_dev->buffer_list))
730 config->mode = INDIO_BUFFER_HARDWARE;
731 strict_scanmask = true;
732 } else if (modes & INDIO_BUFFER_SOFTWARE) {
733 config->mode = INDIO_BUFFER_SOFTWARE;
735 /* Can only occur on first buffer */
736 if (indio_dev->modes & INDIO_BUFFER_TRIGGERED)
737 dev_dbg(&indio_dev->dev, "Buffer not started: no trigger\n");
741 /* What scan mask do we actually have? */
742 compound_mask = kcalloc(BITS_TO_LONGS(indio_dev->masklength),
743 sizeof(long), GFP_KERNEL);
744 if (compound_mask == NULL)
747 scan_timestamp = false;
749 list_for_each_entry(buffer, &indio_dev->buffer_list, buffer_list) {
750 if (buffer == remove_buffer)
752 bitmap_or(compound_mask, compound_mask, buffer->scan_mask,
753 indio_dev->masklength);
754 scan_timestamp |= buffer->scan_timestamp;
758 bitmap_or(compound_mask, compound_mask,
759 insert_buffer->scan_mask, indio_dev->masklength);
760 scan_timestamp |= insert_buffer->scan_timestamp;
763 if (indio_dev->available_scan_masks) {
764 scan_mask = iio_scan_mask_match(indio_dev->available_scan_masks,
765 indio_dev->masklength,
768 kfree(compound_mask);
769 if (scan_mask == NULL)
772 scan_mask = compound_mask;
775 config->scan_bytes = iio_compute_scan_bytes(indio_dev,
776 scan_mask, scan_timestamp);
777 config->scan_mask = scan_mask;
778 config->scan_timestamp = scan_timestamp;
784 * struct iio_demux_table - table describing demux memcpy ops
785 * @from: index to copy from
786 * @to: index to copy to
787 * @length: how many bytes to copy
788 * @l: list head used for management
790 struct iio_demux_table {
797 static void iio_buffer_demux_free(struct iio_buffer *buffer)
799 struct iio_demux_table *p, *q;
800 list_for_each_entry_safe(p, q, &buffer->demux_list, l) {
806 static int iio_buffer_add_demux(struct iio_buffer *buffer,
807 struct iio_demux_table **p, unsigned int in_loc, unsigned int out_loc,
811 if (*p && (*p)->from + (*p)->length == in_loc &&
812 (*p)->to + (*p)->length == out_loc) {
813 (*p)->length += length;
815 *p = kmalloc(sizeof(**p), GFP_KERNEL);
820 (*p)->length = length;
821 list_add_tail(&(*p)->l, &buffer->demux_list);
827 static int iio_buffer_update_demux(struct iio_dev *indio_dev,
828 struct iio_buffer *buffer)
830 int ret, in_ind = -1, out_ind, length;
831 unsigned in_loc = 0, out_loc = 0;
832 struct iio_demux_table *p = NULL;
834 /* Clear out any old demux */
835 iio_buffer_demux_free(buffer);
836 kfree(buffer->demux_bounce);
837 buffer->demux_bounce = NULL;
839 /* First work out which scan mode we will actually have */
840 if (bitmap_equal(indio_dev->active_scan_mask,
842 indio_dev->masklength))
845 /* Now we have the two masks, work from least sig and build up sizes */
846 for_each_set_bit(out_ind,
848 indio_dev->masklength) {
849 in_ind = find_next_bit(indio_dev->active_scan_mask,
850 indio_dev->masklength,
852 while (in_ind != out_ind) {
853 length = iio_storage_bytes_for_si(indio_dev, in_ind);
854 /* Make sure we are aligned */
855 in_loc = roundup(in_loc, length) + length;
856 in_ind = find_next_bit(indio_dev->active_scan_mask,
857 indio_dev->masklength,
860 length = iio_storage_bytes_for_si(indio_dev, in_ind);
861 out_loc = roundup(out_loc, length);
862 in_loc = roundup(in_loc, length);
863 ret = iio_buffer_add_demux(buffer, &p, in_loc, out_loc, length);
865 goto error_clear_mux_table;
869 /* Relies on scan_timestamp being last */
870 if (buffer->scan_timestamp) {
871 length = iio_storage_bytes_for_timestamp(indio_dev);
872 out_loc = roundup(out_loc, length);
873 in_loc = roundup(in_loc, length);
874 ret = iio_buffer_add_demux(buffer, &p, in_loc, out_loc, length);
876 goto error_clear_mux_table;
880 buffer->demux_bounce = kzalloc(out_loc, GFP_KERNEL);
881 if (buffer->demux_bounce == NULL) {
883 goto error_clear_mux_table;
887 error_clear_mux_table:
888 iio_buffer_demux_free(buffer);
893 static int iio_update_demux(struct iio_dev *indio_dev)
895 struct iio_buffer *buffer;
898 list_for_each_entry(buffer, &indio_dev->buffer_list, buffer_list) {
899 ret = iio_buffer_update_demux(indio_dev, buffer);
901 goto error_clear_mux_table;
905 error_clear_mux_table:
906 list_for_each_entry(buffer, &indio_dev->buffer_list, buffer_list)
907 iio_buffer_demux_free(buffer);
912 static int iio_enable_buffers(struct iio_dev *indio_dev,
913 struct iio_device_config *config)
915 struct iio_buffer *buffer;
918 indio_dev->active_scan_mask = config->scan_mask;
919 indio_dev->scan_timestamp = config->scan_timestamp;
920 indio_dev->scan_bytes = config->scan_bytes;
922 iio_update_demux(indio_dev);
925 if (indio_dev->setup_ops->preenable) {
926 ret = indio_dev->setup_ops->preenable(indio_dev);
928 dev_dbg(&indio_dev->dev,
929 "Buffer not started: buffer preenable failed (%d)\n", ret);
930 goto err_undo_config;
934 if (indio_dev->info->update_scan_mode) {
935 ret = indio_dev->info
936 ->update_scan_mode(indio_dev,
937 indio_dev->active_scan_mask);
939 dev_dbg(&indio_dev->dev,
940 "Buffer not started: update scan mode failed (%d)\n",
942 goto err_run_postdisable;
946 if (indio_dev->info->hwfifo_set_watermark)
947 indio_dev->info->hwfifo_set_watermark(indio_dev,
950 list_for_each_entry(buffer, &indio_dev->buffer_list, buffer_list) {
951 ret = iio_buffer_enable(buffer, indio_dev);
953 goto err_disable_buffers;
956 indio_dev->currentmode = config->mode;
958 if (indio_dev->setup_ops->postenable) {
959 ret = indio_dev->setup_ops->postenable(indio_dev);
961 dev_dbg(&indio_dev->dev,
962 "Buffer not started: postenable failed (%d)\n", ret);
963 goto err_disable_buffers;
970 list_for_each_entry_continue_reverse(buffer, &indio_dev->buffer_list,
972 iio_buffer_disable(buffer, indio_dev);
974 indio_dev->currentmode = INDIO_DIRECT_MODE;
975 if (indio_dev->setup_ops->postdisable)
976 indio_dev->setup_ops->postdisable(indio_dev);
978 indio_dev->active_scan_mask = NULL;
983 static int iio_disable_buffers(struct iio_dev *indio_dev)
985 struct iio_buffer *buffer;
989 /* Wind down existing buffers - iff there are any */
990 if (list_empty(&indio_dev->buffer_list))
994 * If things go wrong at some step in disable we still need to continue
995 * to perform the other steps, otherwise we leave the device in a
996 * inconsistent state. We return the error code for the first error we
1000 if (indio_dev->setup_ops->predisable) {
1001 ret2 = indio_dev->setup_ops->predisable(indio_dev);
1006 list_for_each_entry(buffer, &indio_dev->buffer_list, buffer_list) {
1007 ret2 = iio_buffer_disable(buffer, indio_dev);
1012 indio_dev->currentmode = INDIO_DIRECT_MODE;
1014 if (indio_dev->setup_ops->postdisable) {
1015 ret2 = indio_dev->setup_ops->postdisable(indio_dev);
1020 iio_free_scan_mask(indio_dev, indio_dev->active_scan_mask);
1021 indio_dev->active_scan_mask = NULL;
1026 static int __iio_update_buffers(struct iio_dev *indio_dev,
1027 struct iio_buffer *insert_buffer,
1028 struct iio_buffer *remove_buffer)
1030 struct iio_device_config new_config;
1033 ret = iio_verify_update(indio_dev, insert_buffer, remove_buffer,
1038 if (insert_buffer) {
1039 ret = iio_buffer_request_update(indio_dev, insert_buffer);
1041 goto err_free_config;
1044 ret = iio_disable_buffers(indio_dev);
1046 goto err_deactivate_all;
1049 iio_buffer_deactivate(remove_buffer);
1051 iio_buffer_activate(indio_dev, insert_buffer);
1053 /* If no buffers in list, we are done */
1054 if (list_empty(&indio_dev->buffer_list))
1057 ret = iio_enable_buffers(indio_dev, &new_config);
1059 goto err_deactivate_all;
1065 * We've already verified that the config is valid earlier. If things go
1066 * wrong in either enable or disable the most likely reason is an IO
1067 * error from the device. In this case there is no good recovery
1068 * strategy. Just make sure to disable everything and leave the device
1069 * in a sane state. With a bit of luck the device might come back to
1070 * life again later and userspace can try again.
1072 iio_buffer_deactivate_all(indio_dev);
1075 iio_free_scan_mask(indio_dev, new_config.scan_mask);
1079 int iio_update_buffers(struct iio_dev *indio_dev,
1080 struct iio_buffer *insert_buffer,
1081 struct iio_buffer *remove_buffer)
1085 if (insert_buffer == remove_buffer)
1088 mutex_lock(&indio_dev->info_exist_lock);
1089 mutex_lock(&indio_dev->mlock);
1091 if (insert_buffer && iio_buffer_is_active(insert_buffer))
1092 insert_buffer = NULL;
1094 if (remove_buffer && !iio_buffer_is_active(remove_buffer))
1095 remove_buffer = NULL;
1097 if (!insert_buffer && !remove_buffer) {
1102 if (indio_dev->info == NULL) {
1107 ret = __iio_update_buffers(indio_dev, insert_buffer, remove_buffer);
1110 mutex_unlock(&indio_dev->mlock);
1111 mutex_unlock(&indio_dev->info_exist_lock);
1115 EXPORT_SYMBOL_GPL(iio_update_buffers);
1117 void iio_disable_all_buffers(struct iio_dev *indio_dev)
1119 iio_disable_buffers(indio_dev);
1120 iio_buffer_deactivate_all(indio_dev);
1123 static ssize_t iio_buffer_store_enable(struct device *dev,
1124 struct device_attribute *attr,
1129 bool requested_state;
1130 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
1133 ret = strtobool(buf, &requested_state);
1137 mutex_lock(&indio_dev->mlock);
1139 /* Find out if it is in the list */
1140 inlist = iio_buffer_is_active(indio_dev->buffer);
1141 /* Already in desired state */
1142 if (inlist == requested_state)
1145 if (requested_state)
1146 ret = __iio_update_buffers(indio_dev,
1147 indio_dev->buffer, NULL);
1149 ret = __iio_update_buffers(indio_dev,
1150 NULL, indio_dev->buffer);
1153 mutex_unlock(&indio_dev->mlock);
1154 return (ret < 0) ? ret : len;
1157 static const char * const iio_scan_elements_group_name = "scan_elements";
1159 static ssize_t iio_buffer_show_watermark(struct device *dev,
1160 struct device_attribute *attr,
1163 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
1164 struct iio_buffer *buffer = indio_dev->buffer;
1166 return sprintf(buf, "%u\n", buffer->watermark);
1169 static ssize_t iio_buffer_store_watermark(struct device *dev,
1170 struct device_attribute *attr,
1174 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
1175 struct iio_buffer *buffer = indio_dev->buffer;
1179 ret = kstrtouint(buf, 10, &val);
1185 mutex_lock(&indio_dev->mlock);
1187 if (val > buffer->length) {
1192 if (iio_buffer_is_active(indio_dev->buffer)) {
1197 buffer->watermark = val;
1199 mutex_unlock(&indio_dev->mlock);
1201 return ret ? ret : len;
1204 static ssize_t iio_dma_show_data_available(struct device *dev,
1205 struct device_attribute *attr,
1208 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
1211 bytes = iio_buffer_data_available(indio_dev->buffer);
1213 return sprintf(buf, "%zu\n", bytes);
1216 static DEVICE_ATTR(length, S_IRUGO | S_IWUSR, iio_buffer_read_length,
1217 iio_buffer_write_length);
1218 static struct device_attribute dev_attr_length_ro = __ATTR(length,
1219 S_IRUGO, iio_buffer_read_length, NULL);
1220 static DEVICE_ATTR(enable, S_IRUGO | S_IWUSR,
1221 iio_buffer_show_enable, iio_buffer_store_enable);
1222 static DEVICE_ATTR(watermark, S_IRUGO | S_IWUSR,
1223 iio_buffer_show_watermark, iio_buffer_store_watermark);
1224 static struct device_attribute dev_attr_watermark_ro = __ATTR(watermark,
1225 S_IRUGO, iio_buffer_show_watermark, NULL);
1226 static DEVICE_ATTR(data_available, S_IRUGO,
1227 iio_dma_show_data_available, NULL);
1229 static struct attribute *iio_buffer_attrs[] = {
1230 &dev_attr_length.attr,
1231 &dev_attr_enable.attr,
1232 &dev_attr_watermark.attr,
1233 &dev_attr_data_available.attr,
1236 int iio_buffer_alloc_sysfs_and_mask(struct iio_dev *indio_dev)
1238 struct iio_dev_attr *p;
1239 struct attribute **attr;
1240 struct iio_buffer *buffer = indio_dev->buffer;
1241 int ret, i, attrn, attrcount, attrcount_orig = 0;
1242 const struct iio_chan_spec *channels;
1244 channels = indio_dev->channels;
1246 int ml = indio_dev->masklength;
1248 for (i = 0; i < indio_dev->num_channels; i++)
1249 ml = max(ml, channels[i].scan_index + 1);
1250 indio_dev->masklength = ml;
1257 if (buffer->attrs) {
1258 while (buffer->attrs[attrcount] != NULL)
1262 attr = kcalloc(attrcount + ARRAY_SIZE(iio_buffer_attrs) + 1,
1263 sizeof(struct attribute *), GFP_KERNEL);
1267 memcpy(attr, iio_buffer_attrs, sizeof(iio_buffer_attrs));
1268 if (!buffer->access->set_length)
1269 attr[0] = &dev_attr_length_ro.attr;
1271 if (buffer->access->flags & INDIO_BUFFER_FLAG_FIXED_WATERMARK)
1272 attr[2] = &dev_attr_watermark_ro.attr;
1275 memcpy(&attr[ARRAY_SIZE(iio_buffer_attrs)], buffer->attrs,
1276 sizeof(struct attribute *) * attrcount);
1278 attr[attrcount + ARRAY_SIZE(iio_buffer_attrs)] = NULL;
1280 buffer->buffer_group.name = "buffer";
1281 buffer->buffer_group.attrs = attr;
1283 indio_dev->groups[indio_dev->groupcounter++] = &buffer->buffer_group;
1285 if (buffer->scan_el_attrs != NULL) {
1286 attr = buffer->scan_el_attrs->attrs;
1287 while (*attr++ != NULL)
1290 attrcount = attrcount_orig;
1291 INIT_LIST_HEAD(&buffer->scan_el_dev_attr_list);
1292 channels = indio_dev->channels;
1295 for (i = 0; i < indio_dev->num_channels; i++) {
1296 if (channels[i].scan_index < 0)
1299 ret = iio_buffer_add_channel_sysfs(indio_dev,
1302 goto error_cleanup_dynamic;
1304 if (channels[i].type == IIO_TIMESTAMP)
1305 indio_dev->scan_index_timestamp =
1306 channels[i].scan_index;
1308 if (indio_dev->masklength && buffer->scan_mask == NULL) {
1309 buffer->scan_mask = kcalloc(BITS_TO_LONGS(indio_dev->masklength),
1310 sizeof(*buffer->scan_mask),
1312 if (buffer->scan_mask == NULL) {
1314 goto error_cleanup_dynamic;
1319 buffer->scan_el_group.name = iio_scan_elements_group_name;
1321 buffer->scan_el_group.attrs = kcalloc(attrcount + 1,
1322 sizeof(buffer->scan_el_group.attrs[0]),
1324 if (buffer->scan_el_group.attrs == NULL) {
1326 goto error_free_scan_mask;
1328 if (buffer->scan_el_attrs)
1329 memcpy(buffer->scan_el_group.attrs, buffer->scan_el_attrs,
1330 sizeof(buffer->scan_el_group.attrs[0])*attrcount_orig);
1331 attrn = attrcount_orig;
1333 list_for_each_entry(p, &buffer->scan_el_dev_attr_list, l)
1334 buffer->scan_el_group.attrs[attrn++] = &p->dev_attr.attr;
1335 indio_dev->groups[indio_dev->groupcounter++] = &buffer->scan_el_group;
1339 error_free_scan_mask:
1340 kfree(buffer->scan_mask);
1341 error_cleanup_dynamic:
1342 iio_free_chan_devattr_list(&buffer->scan_el_dev_attr_list);
1343 kfree(indio_dev->buffer->buffer_group.attrs);
1348 void iio_buffer_free_sysfs_and_mask(struct iio_dev *indio_dev)
1350 if (!indio_dev->buffer)
1353 kfree(indio_dev->buffer->scan_mask);
1354 kfree(indio_dev->buffer->buffer_group.attrs);
1355 kfree(indio_dev->buffer->scan_el_group.attrs);
1356 iio_free_chan_devattr_list(&indio_dev->buffer->scan_el_dev_attr_list);
1360 * iio_validate_scan_mask_onehot() - Validates that exactly one channel is selected
1361 * @indio_dev: the iio device
1362 * @mask: scan mask to be checked
1364 * Return true if exactly one bit is set in the scan mask, false otherwise. It
1365 * can be used for devices where only one channel can be active for sampling at
1368 bool iio_validate_scan_mask_onehot(struct iio_dev *indio_dev,
1369 const unsigned long *mask)
1371 return bitmap_weight(mask, indio_dev->masklength) == 1;
1373 EXPORT_SYMBOL_GPL(iio_validate_scan_mask_onehot);
1375 static const void *iio_demux(struct iio_buffer *buffer,
1378 struct iio_demux_table *t;
1380 if (list_empty(&buffer->demux_list))
1382 list_for_each_entry(t, &buffer->demux_list, l)
1383 memcpy(buffer->demux_bounce + t->to,
1384 datain + t->from, t->length);
1386 return buffer->demux_bounce;
1389 static int iio_push_to_buffer(struct iio_buffer *buffer, const void *data)
1391 const void *dataout = iio_demux(buffer, data);
1394 ret = buffer->access->store_to(buffer, dataout);
1399 * We can't just test for watermark to decide if we wake the poll queue
1400 * because read may request less samples than the watermark.
1402 wake_up_interruptible_poll(&buffer->pollq, EPOLLIN | EPOLLRDNORM);
1407 * iio_push_to_buffers() - push to a registered buffer.
1408 * @indio_dev: iio_dev structure for device.
1411 int iio_push_to_buffers(struct iio_dev *indio_dev, const void *data)
1414 struct iio_buffer *buf;
1416 list_for_each_entry(buf, &indio_dev->buffer_list, buffer_list) {
1417 ret = iio_push_to_buffer(buf, data);
1424 EXPORT_SYMBOL_GPL(iio_push_to_buffers);
1427 * iio_buffer_release() - Free a buffer's resources
1428 * @ref: Pointer to the kref embedded in the iio_buffer struct
1430 * This function is called when the last reference to the buffer has been
1431 * dropped. It will typically free all resources allocated by the buffer. Do not
1432 * call this function manually, always use iio_buffer_put() when done using a
1435 static void iio_buffer_release(struct kref *ref)
1437 struct iio_buffer *buffer = container_of(ref, struct iio_buffer, ref);
1439 buffer->access->release(buffer);
1443 * iio_buffer_get() - Grab a reference to the buffer
1444 * @buffer: The buffer to grab a reference for, may be NULL
1446 * Returns the pointer to the buffer that was passed into the function.
1448 struct iio_buffer *iio_buffer_get(struct iio_buffer *buffer)
1451 kref_get(&buffer->ref);
1455 EXPORT_SYMBOL_GPL(iio_buffer_get);
1458 * iio_buffer_put() - Release the reference to the buffer
1459 * @buffer: The buffer to release the reference for, may be NULL
1461 void iio_buffer_put(struct iio_buffer *buffer)
1464 kref_put(&buffer->ref, iio_buffer_release);
1466 EXPORT_SYMBOL_GPL(iio_buffer_put);
1469 * iio_device_attach_buffer - Attach a buffer to a IIO device
1470 * @indio_dev: The device the buffer should be attached to
1471 * @buffer: The buffer to attach to the device
1473 * This function attaches a buffer to a IIO device. The buffer stays attached to
1474 * the device until the device is freed. The function should only be called at
1475 * most once per device.
1477 void iio_device_attach_buffer(struct iio_dev *indio_dev,
1478 struct iio_buffer *buffer)
1480 indio_dev->buffer = iio_buffer_get(buffer);
1482 EXPORT_SYMBOL_GPL(iio_device_attach_buffer);