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.h>
25 #include <linux/iio/iio.h>
27 #include <linux/iio/sysfs.h>
28 #include <linux/iio/buffer.h>
30 static const char * const iio_endian_prefix[] = {
35 static bool iio_buffer_is_active(struct iio_buffer *buf)
37 return !list_empty(&buf->buffer_list);
40 static size_t iio_buffer_data_available(struct iio_buffer *buf)
42 return buf->access->data_available(buf);
45 static int iio_buffer_flush_hwfifo(struct iio_dev *indio_dev,
46 struct iio_buffer *buf, size_t required)
48 if (!indio_dev->info->hwfifo_flush_to_buffer)
51 return indio_dev->info->hwfifo_flush_to_buffer(indio_dev, required);
54 static bool iio_buffer_ready(struct iio_dev *indio_dev, struct iio_buffer *buf,
55 size_t to_wait, int to_flush)
60 /* wakeup if the device was unregistered */
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);
70 avail = iio_buffer_data_available(buf);
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, to_flush);
80 flushed = iio_buffer_flush_hwfifo(indio_dev, buf,
85 if (avail + flushed >= to_wait)
92 * iio_buffer_read_first_n_outer() - chrdev read for buffer access
94 * This function relies on all buffer implementations having an
95 * iio_buffer as their first element.
97 ssize_t iio_buffer_read_first_n_outer(struct file *filp, char __user *buf,
98 size_t n, loff_t *f_ps)
100 struct iio_dev *indio_dev = filp->private_data;
101 struct iio_buffer *rb = indio_dev->buffer;
107 if (!indio_dev->info)
110 if (!rb || !rb->access->read_first_n)
113 datum_size = rb->bytes_per_datum;
116 * If datum_size is 0 there will never be anything to read from the
117 * buffer, so signal end of file now.
122 to_read = min_t(size_t, n / datum_size, rb->watermark);
124 if (!(filp->f_flags & O_NONBLOCK))
128 ret = wait_event_interruptible(rb->pollq,
129 iio_buffer_ready(indio_dev, rb, to_wait, to_read));
133 if (!indio_dev->info)
136 ret = rb->access->read_first_n(rb, n, buf);
137 if (ret == 0 && (filp->f_flags & O_NONBLOCK))
145 * iio_buffer_poll() - poll the buffer to find out if it has data
147 unsigned int iio_buffer_poll(struct file *filp,
148 struct poll_table_struct *wait)
150 struct iio_dev *indio_dev = filp->private_data;
151 struct iio_buffer *rb = indio_dev->buffer;
153 if (!indio_dev->info)
156 poll_wait(filp, &rb->pollq, wait);
157 if (iio_buffer_ready(indio_dev, rb, rb->watermark, 0))
158 return POLLIN | POLLRDNORM;
163 * iio_buffer_wakeup_poll - Wakes up the buffer waitqueue
164 * @indio_dev: The IIO device
166 * Wakes up the event waitqueue used for poll(). Should usually
167 * be called when the device is unregistered.
169 void iio_buffer_wakeup_poll(struct iio_dev *indio_dev)
171 if (!indio_dev->buffer)
174 wake_up(&indio_dev->buffer->pollq);
177 void iio_buffer_init(struct iio_buffer *buffer)
179 INIT_LIST_HEAD(&buffer->demux_list);
180 INIT_LIST_HEAD(&buffer->buffer_list);
181 init_waitqueue_head(&buffer->pollq);
182 kref_init(&buffer->ref);
183 buffer->watermark = 1;
185 EXPORT_SYMBOL(iio_buffer_init);
187 static ssize_t iio_show_scan_index(struct device *dev,
188 struct device_attribute *attr,
191 return sprintf(buf, "%u\n", to_iio_dev_attr(attr)->c->scan_index);
194 static ssize_t iio_show_fixed_type(struct device *dev,
195 struct device_attribute *attr,
198 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
199 u8 type = this_attr->c->scan_type.endianness;
201 if (type == IIO_CPU) {
202 #ifdef __LITTLE_ENDIAN
208 if (this_attr->c->scan_type.repeat > 1)
209 return sprintf(buf, "%s:%c%d/%dX%d>>%u\n",
210 iio_endian_prefix[type],
211 this_attr->c->scan_type.sign,
212 this_attr->c->scan_type.realbits,
213 this_attr->c->scan_type.storagebits,
214 this_attr->c->scan_type.repeat,
215 this_attr->c->scan_type.shift);
217 return sprintf(buf, "%s:%c%d/%d>>%u\n",
218 iio_endian_prefix[type],
219 this_attr->c->scan_type.sign,
220 this_attr->c->scan_type.realbits,
221 this_attr->c->scan_type.storagebits,
222 this_attr->c->scan_type.shift);
225 static ssize_t iio_scan_el_show(struct device *dev,
226 struct device_attribute *attr,
230 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
232 /* Ensure ret is 0 or 1. */
233 ret = !!test_bit(to_iio_dev_attr(attr)->address,
234 indio_dev->buffer->scan_mask);
236 return sprintf(buf, "%d\n", ret);
239 /* Note NULL used as error indicator as it doesn't make sense. */
240 static const unsigned long *iio_scan_mask_match(const unsigned long *av_masks,
241 unsigned int masklength,
242 const unsigned long *mask,
245 if (bitmap_empty(mask, masklength))
249 if (bitmap_equal(mask, av_masks, masklength))
252 if (bitmap_subset(mask, av_masks, masklength))
255 av_masks += BITS_TO_LONGS(masklength);
260 static bool iio_validate_scan_mask(struct iio_dev *indio_dev,
261 const unsigned long *mask)
263 if (!indio_dev->setup_ops->validate_scan_mask)
266 return indio_dev->setup_ops->validate_scan_mask(indio_dev, mask);
270 * iio_scan_mask_set() - set particular bit in the scan mask
271 * @indio_dev: the iio device
272 * @buffer: the buffer whose scan mask we are interested in
273 * @bit: the bit to be set.
275 * Note that at this point we have no way of knowing what other
276 * buffers might request, hence this code only verifies that the
277 * individual buffers request is plausible.
279 static int iio_scan_mask_set(struct iio_dev *indio_dev,
280 struct iio_buffer *buffer, int bit)
282 const unsigned long *mask;
283 unsigned long *trialmask;
285 trialmask = kmalloc(sizeof(*trialmask)*
286 BITS_TO_LONGS(indio_dev->masklength),
289 if (trialmask == NULL)
291 if (!indio_dev->masklength) {
292 WARN_ON("Trying to set scanmask prior to registering buffer\n");
293 goto err_invalid_mask;
295 bitmap_copy(trialmask, buffer->scan_mask, indio_dev->masklength);
296 set_bit(bit, trialmask);
298 if (!iio_validate_scan_mask(indio_dev, trialmask))
299 goto err_invalid_mask;
301 if (indio_dev->available_scan_masks) {
302 mask = iio_scan_mask_match(indio_dev->available_scan_masks,
303 indio_dev->masklength,
306 goto err_invalid_mask;
308 bitmap_copy(buffer->scan_mask, trialmask, indio_dev->masklength);
319 static int iio_scan_mask_clear(struct iio_buffer *buffer, int bit)
321 clear_bit(bit, buffer->scan_mask);
325 static ssize_t iio_scan_el_store(struct device *dev,
326 struct device_attribute *attr,
332 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
333 struct iio_buffer *buffer = indio_dev->buffer;
334 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
336 ret = strtobool(buf, &state);
339 mutex_lock(&indio_dev->mlock);
340 if (iio_buffer_is_active(indio_dev->buffer)) {
344 ret = iio_scan_mask_query(indio_dev, buffer, this_attr->address);
348 ret = iio_scan_mask_clear(buffer, this_attr->address);
351 } else if (state && !ret) {
352 ret = iio_scan_mask_set(indio_dev, buffer, this_attr->address);
358 mutex_unlock(&indio_dev->mlock);
360 return ret < 0 ? ret : len;
364 static ssize_t iio_scan_el_ts_show(struct device *dev,
365 struct device_attribute *attr,
368 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
369 return sprintf(buf, "%d\n", indio_dev->buffer->scan_timestamp);
372 static ssize_t iio_scan_el_ts_store(struct device *dev,
373 struct device_attribute *attr,
378 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
381 ret = strtobool(buf, &state);
385 mutex_lock(&indio_dev->mlock);
386 if (iio_buffer_is_active(indio_dev->buffer)) {
390 indio_dev->buffer->scan_timestamp = state;
392 mutex_unlock(&indio_dev->mlock);
394 return ret ? ret : len;
397 static int iio_buffer_add_channel_sysfs(struct iio_dev *indio_dev,
398 const struct iio_chan_spec *chan)
400 int ret, attrcount = 0;
401 struct iio_buffer *buffer = indio_dev->buffer;
403 ret = __iio_add_chan_devattr("index",
405 &iio_show_scan_index,
410 &buffer->scan_el_dev_attr_list);
414 ret = __iio_add_chan_devattr("type",
416 &iio_show_fixed_type,
421 &buffer->scan_el_dev_attr_list);
425 if (chan->type != IIO_TIMESTAMP)
426 ret = __iio_add_chan_devattr("en",
433 &buffer->scan_el_dev_attr_list);
435 ret = __iio_add_chan_devattr("en",
437 &iio_scan_el_ts_show,
438 &iio_scan_el_ts_store,
442 &buffer->scan_el_dev_attr_list);
450 static ssize_t iio_buffer_read_length(struct device *dev,
451 struct device_attribute *attr,
454 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
455 struct iio_buffer *buffer = indio_dev->buffer;
457 return sprintf(buf, "%d\n", buffer->length);
460 static ssize_t iio_buffer_write_length(struct device *dev,
461 struct device_attribute *attr,
462 const char *buf, size_t len)
464 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
465 struct iio_buffer *buffer = indio_dev->buffer;
469 ret = kstrtouint(buf, 10, &val);
473 if (val == buffer->length)
476 mutex_lock(&indio_dev->mlock);
477 if (iio_buffer_is_active(indio_dev->buffer)) {
480 buffer->access->set_length(buffer, val);
485 if (buffer->length && buffer->length < buffer->watermark)
486 buffer->watermark = buffer->length;
488 mutex_unlock(&indio_dev->mlock);
490 return ret ? ret : len;
493 static ssize_t iio_buffer_show_enable(struct device *dev,
494 struct device_attribute *attr,
497 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
498 return sprintf(buf, "%d\n", iio_buffer_is_active(indio_dev->buffer));
501 static int iio_compute_scan_bytes(struct iio_dev *indio_dev,
502 const unsigned long *mask, bool timestamp)
504 const struct iio_chan_spec *ch;
508 /* How much space will the demuxed element take? */
509 for_each_set_bit(i, mask,
510 indio_dev->masklength) {
511 ch = iio_find_channel_from_si(indio_dev, i);
512 if (ch->scan_type.repeat > 1)
513 length = ch->scan_type.storagebits / 8 *
514 ch->scan_type.repeat;
516 length = ch->scan_type.storagebits / 8;
517 bytes = ALIGN(bytes, length);
521 ch = iio_find_channel_from_si(indio_dev,
522 indio_dev->scan_index_timestamp);
523 if (ch->scan_type.repeat > 1)
524 length = ch->scan_type.storagebits / 8 *
525 ch->scan_type.repeat;
527 length = ch->scan_type.storagebits / 8;
528 bytes = ALIGN(bytes, length);
534 static void iio_buffer_activate(struct iio_dev *indio_dev,
535 struct iio_buffer *buffer)
537 iio_buffer_get(buffer);
538 list_add(&buffer->buffer_list, &indio_dev->buffer_list);
541 static void iio_buffer_deactivate(struct iio_buffer *buffer)
543 list_del_init(&buffer->buffer_list);
544 wake_up_interruptible(&buffer->pollq);
545 iio_buffer_put(buffer);
548 static void iio_buffer_deactivate_all(struct iio_dev *indio_dev)
550 struct iio_buffer *buffer, *_buffer;
552 list_for_each_entry_safe(buffer, _buffer,
553 &indio_dev->buffer_list, buffer_list)
554 iio_buffer_deactivate(buffer);
557 static void iio_buffer_update_bytes_per_datum(struct iio_dev *indio_dev,
558 struct iio_buffer *buffer)
562 if (!buffer->access->set_bytes_per_datum)
565 bytes = iio_compute_scan_bytes(indio_dev, buffer->scan_mask,
566 buffer->scan_timestamp);
568 buffer->access->set_bytes_per_datum(buffer, bytes);
571 static int iio_buffer_request_update(struct iio_dev *indio_dev,
572 struct iio_buffer *buffer)
576 iio_buffer_update_bytes_per_datum(indio_dev, buffer);
577 if (buffer->access->request_update) {
578 ret = buffer->access->request_update(buffer);
580 dev_dbg(&indio_dev->dev,
581 "Buffer not started: buffer parameter update failed (%d)\n",
590 static void iio_free_scan_mask(struct iio_dev *indio_dev,
591 const unsigned long *mask)
593 /* If the mask is dynamically allocated free it, otherwise do nothing */
594 if (!indio_dev->available_scan_masks)
598 struct iio_device_config {
600 const unsigned long *scan_mask;
601 unsigned int scan_bytes;
605 static int iio_verify_update(struct iio_dev *indio_dev,
606 struct iio_buffer *insert_buffer, struct iio_buffer *remove_buffer,
607 struct iio_device_config *config)
609 unsigned long *compound_mask;
610 const unsigned long *scan_mask;
611 bool strict_scanmask = false;
612 struct iio_buffer *buffer;
616 memset(config, 0, sizeof(*config));
619 * If there is just one buffer and we are removing it there is nothing
622 if (remove_buffer && !insert_buffer &&
623 list_is_singular(&indio_dev->buffer_list))
626 modes = indio_dev->modes;
628 list_for_each_entry(buffer, &indio_dev->buffer_list, buffer_list) {
629 if (buffer == remove_buffer)
631 modes &= buffer->access->modes;
635 modes &= insert_buffer->access->modes;
637 /* Definitely possible for devices to support both of these. */
638 if ((modes & INDIO_BUFFER_TRIGGERED) && indio_dev->trig) {
639 config->mode = INDIO_BUFFER_TRIGGERED;
640 } else if (modes & INDIO_BUFFER_HARDWARE) {
642 * Keep things simple for now and only allow a single buffer to
643 * be connected in hardware mode.
645 if (insert_buffer && !list_empty(&indio_dev->buffer_list))
647 config->mode = INDIO_BUFFER_HARDWARE;
648 strict_scanmask = true;
649 } else if (modes & INDIO_BUFFER_SOFTWARE) {
650 config->mode = INDIO_BUFFER_SOFTWARE;
652 /* Can only occur on first buffer */
653 if (indio_dev->modes & INDIO_BUFFER_TRIGGERED)
654 dev_dbg(&indio_dev->dev, "Buffer not started: no trigger\n");
658 /* What scan mask do we actually have? */
659 compound_mask = kcalloc(BITS_TO_LONGS(indio_dev->masklength),
660 sizeof(long), GFP_KERNEL);
661 if (compound_mask == NULL)
664 scan_timestamp = false;
666 list_for_each_entry(buffer, &indio_dev->buffer_list, buffer_list) {
667 if (buffer == remove_buffer)
669 bitmap_or(compound_mask, compound_mask, buffer->scan_mask,
670 indio_dev->masklength);
671 scan_timestamp |= buffer->scan_timestamp;
675 bitmap_or(compound_mask, compound_mask,
676 insert_buffer->scan_mask, indio_dev->masklength);
677 scan_timestamp |= insert_buffer->scan_timestamp;
680 if (indio_dev->available_scan_masks) {
681 scan_mask = iio_scan_mask_match(indio_dev->available_scan_masks,
682 indio_dev->masklength,
685 kfree(compound_mask);
686 if (scan_mask == NULL)
689 scan_mask = compound_mask;
692 config->scan_bytes = iio_compute_scan_bytes(indio_dev,
693 scan_mask, scan_timestamp);
694 config->scan_mask = scan_mask;
695 config->scan_timestamp = scan_timestamp;
700 static int iio_enable_buffers(struct iio_dev *indio_dev,
701 struct iio_device_config *config)
705 indio_dev->active_scan_mask = config->scan_mask;
706 indio_dev->scan_timestamp = config->scan_timestamp;
707 indio_dev->scan_bytes = config->scan_bytes;
709 iio_update_demux(indio_dev);
712 if (indio_dev->setup_ops->preenable) {
713 ret = indio_dev->setup_ops->preenable(indio_dev);
715 dev_dbg(&indio_dev->dev,
716 "Buffer not started: buffer preenable failed (%d)\n", ret);
717 goto err_undo_config;
721 if (indio_dev->info->update_scan_mode) {
722 ret = indio_dev->info
723 ->update_scan_mode(indio_dev,
724 indio_dev->active_scan_mask);
726 dev_dbg(&indio_dev->dev,
727 "Buffer not started: update scan mode failed (%d)\n",
729 goto err_run_postdisable;
733 indio_dev->currentmode = config->mode;
735 if (indio_dev->setup_ops->postenable) {
736 ret = indio_dev->setup_ops->postenable(indio_dev);
738 dev_dbg(&indio_dev->dev,
739 "Buffer not started: postenable failed (%d)\n", ret);
740 goto err_run_postdisable;
747 indio_dev->currentmode = INDIO_DIRECT_MODE;
748 if (indio_dev->setup_ops->postdisable)
749 indio_dev->setup_ops->postdisable(indio_dev);
751 indio_dev->active_scan_mask = NULL;
756 static int iio_disable_buffers(struct iio_dev *indio_dev)
761 /* Wind down existing buffers - iff there are any */
762 if (list_empty(&indio_dev->buffer_list))
766 * If things go wrong at some step in disable we still need to continue
767 * to perform the other steps, otherwise we leave the device in a
768 * inconsistent state. We return the error code for the first error we
772 if (indio_dev->setup_ops->predisable) {
773 ret2 = indio_dev->setup_ops->predisable(indio_dev);
778 indio_dev->currentmode = INDIO_DIRECT_MODE;
780 if (indio_dev->setup_ops->postdisable) {
781 ret2 = indio_dev->setup_ops->postdisable(indio_dev);
786 iio_free_scan_mask(indio_dev, indio_dev->active_scan_mask);
787 indio_dev->active_scan_mask = NULL;
792 static int __iio_update_buffers(struct iio_dev *indio_dev,
793 struct iio_buffer *insert_buffer,
794 struct iio_buffer *remove_buffer)
796 struct iio_device_config new_config;
799 ret = iio_verify_update(indio_dev, insert_buffer, remove_buffer,
805 ret = iio_buffer_request_update(indio_dev, insert_buffer);
807 goto err_free_config;
810 ret = iio_disable_buffers(indio_dev);
812 goto err_deactivate_all;
815 iio_buffer_deactivate(remove_buffer);
817 iio_buffer_activate(indio_dev, insert_buffer);
819 /* If no buffers in list, we are done */
820 if (list_empty(&indio_dev->buffer_list))
823 ret = iio_enable_buffers(indio_dev, &new_config);
825 goto err_deactivate_all;
831 * We've already verified that the config is valid earlier. If things go
832 * wrong in either enable or disable the most likely reason is an IO
833 * error from the device. In this case there is no good recovery
834 * strategy. Just make sure to disable everything and leave the device
835 * in a sane state. With a bit of luck the device might come back to
836 * life again later and userspace can try again.
838 iio_buffer_deactivate_all(indio_dev);
841 iio_free_scan_mask(indio_dev, new_config.scan_mask);
845 int iio_update_buffers(struct iio_dev *indio_dev,
846 struct iio_buffer *insert_buffer,
847 struct iio_buffer *remove_buffer)
851 if (insert_buffer == remove_buffer)
854 mutex_lock(&indio_dev->info_exist_lock);
855 mutex_lock(&indio_dev->mlock);
857 if (insert_buffer && iio_buffer_is_active(insert_buffer))
858 insert_buffer = NULL;
860 if (remove_buffer && !iio_buffer_is_active(remove_buffer))
861 remove_buffer = NULL;
863 if (!insert_buffer && !remove_buffer) {
868 if (indio_dev->info == NULL) {
873 ret = __iio_update_buffers(indio_dev, insert_buffer, remove_buffer);
876 mutex_unlock(&indio_dev->mlock);
877 mutex_unlock(&indio_dev->info_exist_lock);
881 EXPORT_SYMBOL_GPL(iio_update_buffers);
883 void iio_disable_all_buffers(struct iio_dev *indio_dev)
885 iio_disable_buffers(indio_dev);
886 iio_buffer_deactivate_all(indio_dev);
889 static ssize_t iio_buffer_store_enable(struct device *dev,
890 struct device_attribute *attr,
895 bool requested_state;
896 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
899 ret = strtobool(buf, &requested_state);
903 mutex_lock(&indio_dev->mlock);
905 /* Find out if it is in the list */
906 inlist = iio_buffer_is_active(indio_dev->buffer);
907 /* Already in desired state */
908 if (inlist == requested_state)
912 ret = __iio_update_buffers(indio_dev,
913 indio_dev->buffer, NULL);
915 ret = __iio_update_buffers(indio_dev,
916 NULL, indio_dev->buffer);
919 mutex_unlock(&indio_dev->mlock);
920 return (ret < 0) ? ret : len;
923 static const char * const iio_scan_elements_group_name = "scan_elements";
925 static ssize_t iio_buffer_show_watermark(struct device *dev,
926 struct device_attribute *attr,
929 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
930 struct iio_buffer *buffer = indio_dev->buffer;
932 return sprintf(buf, "%u\n", buffer->watermark);
935 static ssize_t iio_buffer_store_watermark(struct device *dev,
936 struct device_attribute *attr,
940 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
941 struct iio_buffer *buffer = indio_dev->buffer;
945 ret = kstrtouint(buf, 10, &val);
951 mutex_lock(&indio_dev->mlock);
953 if (val > buffer->length) {
958 if (iio_buffer_is_active(indio_dev->buffer)) {
963 buffer->watermark = val;
965 if (indio_dev->info->hwfifo_set_watermark)
966 indio_dev->info->hwfifo_set_watermark(indio_dev, val);
968 mutex_unlock(&indio_dev->mlock);
970 return ret ? ret : len;
973 static DEVICE_ATTR(length, S_IRUGO | S_IWUSR, iio_buffer_read_length,
974 iio_buffer_write_length);
975 static struct device_attribute dev_attr_length_ro = __ATTR(length,
976 S_IRUGO, iio_buffer_read_length, NULL);
977 static DEVICE_ATTR(enable, S_IRUGO | S_IWUSR,
978 iio_buffer_show_enable, iio_buffer_store_enable);
979 static DEVICE_ATTR(watermark, S_IRUGO | S_IWUSR,
980 iio_buffer_show_watermark, iio_buffer_store_watermark);
982 static struct attribute *iio_buffer_attrs[] = {
983 &dev_attr_length.attr,
984 &dev_attr_enable.attr,
985 &dev_attr_watermark.attr,
988 int iio_buffer_alloc_sysfs_and_mask(struct iio_dev *indio_dev)
990 struct iio_dev_attr *p;
991 struct attribute **attr;
992 struct iio_buffer *buffer = indio_dev->buffer;
993 int ret, i, attrn, attrcount, attrcount_orig = 0;
994 const struct iio_chan_spec *channels;
996 channels = indio_dev->channels;
998 int ml = indio_dev->masklength;
1000 for (i = 0; i < indio_dev->num_channels; i++)
1001 ml = max(ml, channels[i].scan_index + 1);
1002 indio_dev->masklength = ml;
1009 if (buffer->attrs) {
1010 while (buffer->attrs[attrcount] != NULL)
1014 attr = kcalloc(attrcount + ARRAY_SIZE(iio_buffer_attrs) + 1,
1015 sizeof(struct attribute *), GFP_KERNEL);
1019 memcpy(attr, iio_buffer_attrs, sizeof(iio_buffer_attrs));
1020 if (!buffer->access->set_length)
1021 attr[0] = &dev_attr_length_ro.attr;
1024 memcpy(&attr[ARRAY_SIZE(iio_buffer_attrs)], buffer->attrs,
1025 sizeof(struct attribute *) * attrcount);
1027 attr[attrcount + ARRAY_SIZE(iio_buffer_attrs)] = NULL;
1029 buffer->buffer_group.name = "buffer";
1030 buffer->buffer_group.attrs = attr;
1032 indio_dev->groups[indio_dev->groupcounter++] = &buffer->buffer_group;
1034 if (buffer->scan_el_attrs != NULL) {
1035 attr = buffer->scan_el_attrs->attrs;
1036 while (*attr++ != NULL)
1039 attrcount = attrcount_orig;
1040 INIT_LIST_HEAD(&buffer->scan_el_dev_attr_list);
1041 channels = indio_dev->channels;
1044 for (i = 0; i < indio_dev->num_channels; i++) {
1045 if (channels[i].scan_index < 0)
1048 ret = iio_buffer_add_channel_sysfs(indio_dev,
1051 goto error_cleanup_dynamic;
1053 if (channels[i].type == IIO_TIMESTAMP)
1054 indio_dev->scan_index_timestamp =
1055 channels[i].scan_index;
1057 if (indio_dev->masklength && buffer->scan_mask == NULL) {
1058 buffer->scan_mask = kcalloc(BITS_TO_LONGS(indio_dev->masklength),
1059 sizeof(*buffer->scan_mask),
1061 if (buffer->scan_mask == NULL) {
1063 goto error_cleanup_dynamic;
1068 buffer->scan_el_group.name = iio_scan_elements_group_name;
1070 buffer->scan_el_group.attrs = kcalloc(attrcount + 1,
1071 sizeof(buffer->scan_el_group.attrs[0]),
1073 if (buffer->scan_el_group.attrs == NULL) {
1075 goto error_free_scan_mask;
1077 if (buffer->scan_el_attrs)
1078 memcpy(buffer->scan_el_group.attrs, buffer->scan_el_attrs,
1079 sizeof(buffer->scan_el_group.attrs[0])*attrcount_orig);
1080 attrn = attrcount_orig;
1082 list_for_each_entry(p, &buffer->scan_el_dev_attr_list, l)
1083 buffer->scan_el_group.attrs[attrn++] = &p->dev_attr.attr;
1084 indio_dev->groups[indio_dev->groupcounter++] = &buffer->scan_el_group;
1088 error_free_scan_mask:
1089 kfree(buffer->scan_mask);
1090 error_cleanup_dynamic:
1091 iio_free_chan_devattr_list(&buffer->scan_el_dev_attr_list);
1092 kfree(indio_dev->buffer->buffer_group.attrs);
1097 void iio_buffer_free_sysfs_and_mask(struct iio_dev *indio_dev)
1099 if (!indio_dev->buffer)
1102 kfree(indio_dev->buffer->scan_mask);
1103 kfree(indio_dev->buffer->buffer_group.attrs);
1104 kfree(indio_dev->buffer->scan_el_group.attrs);
1105 iio_free_chan_devattr_list(&indio_dev->buffer->scan_el_dev_attr_list);
1109 * iio_validate_scan_mask_onehot() - Validates that exactly one channel is selected
1110 * @indio_dev: the iio device
1111 * @mask: scan mask to be checked
1113 * Return true if exactly one bit is set in the scan mask, false otherwise. It
1114 * can be used for devices where only one channel can be active for sampling at
1117 bool iio_validate_scan_mask_onehot(struct iio_dev *indio_dev,
1118 const unsigned long *mask)
1120 return bitmap_weight(mask, indio_dev->masklength) == 1;
1122 EXPORT_SYMBOL_GPL(iio_validate_scan_mask_onehot);
1124 int iio_scan_mask_query(struct iio_dev *indio_dev,
1125 struct iio_buffer *buffer, int bit)
1127 if (bit > indio_dev->masklength)
1130 if (!buffer->scan_mask)
1133 /* Ensure return value is 0 or 1. */
1134 return !!test_bit(bit, buffer->scan_mask);
1136 EXPORT_SYMBOL_GPL(iio_scan_mask_query);
1139 * struct iio_demux_table() - table describing demux memcpy ops
1140 * @from: index to copy from
1141 * @to: index to copy to
1142 * @length: how many bytes to copy
1143 * @l: list head used for management
1145 struct iio_demux_table {
1152 static const void *iio_demux(struct iio_buffer *buffer,
1155 struct iio_demux_table *t;
1157 if (list_empty(&buffer->demux_list))
1159 list_for_each_entry(t, &buffer->demux_list, l)
1160 memcpy(buffer->demux_bounce + t->to,
1161 datain + t->from, t->length);
1163 return buffer->demux_bounce;
1166 static int iio_push_to_buffer(struct iio_buffer *buffer, const void *data)
1168 const void *dataout = iio_demux(buffer, data);
1171 ret = buffer->access->store_to(buffer, dataout);
1176 * We can't just test for watermark to decide if we wake the poll queue
1177 * because read may request less samples than the watermark.
1179 wake_up_interruptible_poll(&buffer->pollq, POLLIN | POLLRDNORM);
1183 static void iio_buffer_demux_free(struct iio_buffer *buffer)
1185 struct iio_demux_table *p, *q;
1186 list_for_each_entry_safe(p, q, &buffer->demux_list, l) {
1193 int iio_push_to_buffers(struct iio_dev *indio_dev, const void *data)
1196 struct iio_buffer *buf;
1198 list_for_each_entry(buf, &indio_dev->buffer_list, buffer_list) {
1199 ret = iio_push_to_buffer(buf, data);
1206 EXPORT_SYMBOL_GPL(iio_push_to_buffers);
1208 static int iio_buffer_add_demux(struct iio_buffer *buffer,
1209 struct iio_demux_table **p, unsigned int in_loc, unsigned int out_loc,
1210 unsigned int length)
1213 if (*p && (*p)->from + (*p)->length == in_loc &&
1214 (*p)->to + (*p)->length == out_loc) {
1215 (*p)->length += length;
1217 *p = kmalloc(sizeof(**p), GFP_KERNEL);
1220 (*p)->from = in_loc;
1222 (*p)->length = length;
1223 list_add_tail(&(*p)->l, &buffer->demux_list);
1229 static int iio_buffer_update_demux(struct iio_dev *indio_dev,
1230 struct iio_buffer *buffer)
1232 const struct iio_chan_spec *ch;
1233 int ret, in_ind = -1, out_ind, length;
1234 unsigned in_loc = 0, out_loc = 0;
1235 struct iio_demux_table *p = NULL;
1237 /* Clear out any old demux */
1238 iio_buffer_demux_free(buffer);
1239 kfree(buffer->demux_bounce);
1240 buffer->demux_bounce = NULL;
1242 /* First work out which scan mode we will actually have */
1243 if (bitmap_equal(indio_dev->active_scan_mask,
1245 indio_dev->masklength))
1248 /* Now we have the two masks, work from least sig and build up sizes */
1249 for_each_set_bit(out_ind,
1251 indio_dev->masklength) {
1252 in_ind = find_next_bit(indio_dev->active_scan_mask,
1253 indio_dev->masklength,
1255 while (in_ind != out_ind) {
1256 in_ind = find_next_bit(indio_dev->active_scan_mask,
1257 indio_dev->masklength,
1259 ch = iio_find_channel_from_si(indio_dev, in_ind);
1260 if (ch->scan_type.repeat > 1)
1261 length = ch->scan_type.storagebits / 8 *
1262 ch->scan_type.repeat;
1264 length = ch->scan_type.storagebits / 8;
1265 /* Make sure we are aligned */
1266 in_loc = roundup(in_loc, length) + length;
1268 ch = iio_find_channel_from_si(indio_dev, in_ind);
1269 if (ch->scan_type.repeat > 1)
1270 length = ch->scan_type.storagebits / 8 *
1271 ch->scan_type.repeat;
1273 length = ch->scan_type.storagebits / 8;
1274 out_loc = roundup(out_loc, length);
1275 in_loc = roundup(in_loc, length);
1276 ret = iio_buffer_add_demux(buffer, &p, in_loc, out_loc, length);
1278 goto error_clear_mux_table;
1282 /* Relies on scan_timestamp being last */
1283 if (buffer->scan_timestamp) {
1284 ch = iio_find_channel_from_si(indio_dev,
1285 indio_dev->scan_index_timestamp);
1286 if (ch->scan_type.repeat > 1)
1287 length = ch->scan_type.storagebits / 8 *
1288 ch->scan_type.repeat;
1290 length = ch->scan_type.storagebits / 8;
1291 out_loc = roundup(out_loc, length);
1292 in_loc = roundup(in_loc, length);
1293 ret = iio_buffer_add_demux(buffer, &p, in_loc, out_loc, length);
1295 goto error_clear_mux_table;
1299 buffer->demux_bounce = kzalloc(out_loc, GFP_KERNEL);
1300 if (buffer->demux_bounce == NULL) {
1302 goto error_clear_mux_table;
1306 error_clear_mux_table:
1307 iio_buffer_demux_free(buffer);
1312 int iio_update_demux(struct iio_dev *indio_dev)
1314 struct iio_buffer *buffer;
1317 list_for_each_entry(buffer, &indio_dev->buffer_list, buffer_list) {
1318 ret = iio_buffer_update_demux(indio_dev, buffer);
1320 goto error_clear_mux_table;
1324 error_clear_mux_table:
1325 list_for_each_entry(buffer, &indio_dev->buffer_list, buffer_list)
1326 iio_buffer_demux_free(buffer);
1330 EXPORT_SYMBOL_GPL(iio_update_demux);
1333 * iio_buffer_release() - Free a buffer's resources
1334 * @ref: Pointer to the kref embedded in the iio_buffer struct
1336 * This function is called when the last reference to the buffer has been
1337 * dropped. It will typically free all resources allocated by the buffer. Do not
1338 * call this function manually, always use iio_buffer_put() when done using a
1341 static void iio_buffer_release(struct kref *ref)
1343 struct iio_buffer *buffer = container_of(ref, struct iio_buffer, ref);
1345 buffer->access->release(buffer);
1349 * iio_buffer_get() - Grab a reference to the buffer
1350 * @buffer: The buffer to grab a reference for, may be NULL
1352 * Returns the pointer to the buffer that was passed into the function.
1354 struct iio_buffer *iio_buffer_get(struct iio_buffer *buffer)
1357 kref_get(&buffer->ref);
1361 EXPORT_SYMBOL_GPL(iio_buffer_get);
1364 * iio_buffer_put() - Release the reference to the buffer
1365 * @buffer: The buffer to release the reference for, may be NULL
1367 void iio_buffer_put(struct iio_buffer *buffer)
1370 kref_put(&buffer->ref, iio_buffer_release);
1372 EXPORT_SYMBOL_GPL(iio_buffer_put);