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,
81 flushed = iio_buffer_flush_hwfifo(indio_dev, buf,
86 if (avail + flushed >= to_wait)
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
99 * This function relies on all buffer implementations having an
100 * iio_buffer as their first element.
102 * Return: negative values corresponding to error codes or ret != 0
103 * for ending the reading activity
105 ssize_t iio_buffer_read_first_n_outer(struct file *filp, char __user *buf,
106 size_t n, loff_t *f_ps)
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);
115 if (!indio_dev->info)
118 if (!rb || !rb->access->read_first_n)
121 datum_size = rb->bytes_per_datum;
124 * If datum_size is 0 there will never be anything to read from the
125 * buffer, so signal end of file now.
130 if (filp->f_flags & O_NONBLOCK)
133 to_wait = min_t(size_t, n / datum_size, rb->watermark);
135 add_wait_queue(&rb->pollq, &wait);
137 if (!indio_dev->info) {
142 if (!iio_buffer_ready(indio_dev, rb, to_wait, n / datum_size)) {
143 if (signal_pending(current)) {
148 wait_woken(&wait, TASK_INTERRUPTIBLE,
149 MAX_SCHEDULE_TIMEOUT);
153 ret = rb->access->read_first_n(rb, n, buf);
154 if (ret == 0 && (filp->f_flags & O_NONBLOCK))
157 remove_wait_queue(&rb->pollq, &wait);
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
168 * Return: (POLLIN | POLLRDNORM) if data is available for reading
169 * or 0 for other cases
171 unsigned int iio_buffer_poll(struct file *filp,
172 struct poll_table_struct *wait)
174 struct iio_dev *indio_dev = filp->private_data;
175 struct iio_buffer *rb = indio_dev->buffer;
177 if (!indio_dev->info || rb == NULL)
180 poll_wait(filp, &rb->pollq, wait);
181 if (iio_buffer_ready(indio_dev, rb, rb->watermark, 0))
182 return POLLIN | POLLRDNORM;
187 * iio_buffer_wakeup_poll - Wakes up the buffer waitqueue
188 * @indio_dev: The IIO device
190 * Wakes up the event waitqueue used for poll(). Should usually
191 * be called when the device is unregistered.
193 void iio_buffer_wakeup_poll(struct iio_dev *indio_dev)
195 if (!indio_dev->buffer)
198 wake_up(&indio_dev->buffer->pollq);
201 void iio_buffer_init(struct iio_buffer *buffer)
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;
209 EXPORT_SYMBOL(iio_buffer_init);
211 static ssize_t iio_show_scan_index(struct device *dev,
212 struct device_attribute *attr,
215 return sprintf(buf, "%u\n", to_iio_dev_attr(attr)->c->scan_index);
218 static ssize_t iio_show_fixed_type(struct device *dev,
219 struct device_attribute *attr,
222 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
223 u8 type = this_attr->c->scan_type.endianness;
225 if (type == IIO_CPU) {
226 #ifdef __LITTLE_ENDIAN
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);
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);
249 static ssize_t iio_scan_el_show(struct device *dev,
250 struct device_attribute *attr,
254 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
256 /* Ensure ret is 0 or 1. */
257 ret = !!test_bit(to_iio_dev_attr(attr)->address,
258 indio_dev->buffer->scan_mask);
260 return sprintf(buf, "%d\n", ret);
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,
269 if (bitmap_empty(mask, masklength))
273 if (bitmap_equal(mask, av_masks, masklength))
276 if (bitmap_subset(mask, av_masks, masklength))
279 av_masks += BITS_TO_LONGS(masklength);
284 static bool iio_validate_scan_mask(struct iio_dev *indio_dev,
285 const unsigned long *mask)
287 if (!indio_dev->setup_ops->validate_scan_mask)
290 return indio_dev->setup_ops->validate_scan_mask(indio_dev, mask);
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.
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.
303 static int iio_scan_mask_set(struct iio_dev *indio_dev,
304 struct iio_buffer *buffer, int bit)
306 const unsigned long *mask;
307 unsigned long *trialmask;
309 trialmask = kmalloc(sizeof(*trialmask)*
310 BITS_TO_LONGS(indio_dev->masklength),
313 if (trialmask == NULL)
315 if (!indio_dev->masklength) {
316 WARN(1, "Trying to set scanmask prior to registering buffer\n");
317 goto err_invalid_mask;
319 bitmap_copy(trialmask, buffer->scan_mask, indio_dev->masklength);
320 set_bit(bit, trialmask);
322 if (!iio_validate_scan_mask(indio_dev, trialmask))
323 goto err_invalid_mask;
325 if (indio_dev->available_scan_masks) {
326 mask = iio_scan_mask_match(indio_dev->available_scan_masks,
327 indio_dev->masklength,
330 goto err_invalid_mask;
332 bitmap_copy(buffer->scan_mask, trialmask, indio_dev->masklength);
343 static int iio_scan_mask_clear(struct iio_buffer *buffer, int bit)
345 clear_bit(bit, buffer->scan_mask);
349 static ssize_t iio_scan_el_store(struct device *dev,
350 struct device_attribute *attr,
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);
360 ret = strtobool(buf, &state);
363 mutex_lock(&indio_dev->mlock);
364 if (iio_buffer_is_active(indio_dev->buffer)) {
368 ret = iio_scan_mask_query(indio_dev, buffer, this_attr->address);
372 ret = iio_scan_mask_clear(buffer, this_attr->address);
375 } else if (state && !ret) {
376 ret = iio_scan_mask_set(indio_dev, buffer, this_attr->address);
382 mutex_unlock(&indio_dev->mlock);
384 return ret < 0 ? ret : len;
388 static ssize_t iio_scan_el_ts_show(struct device *dev,
389 struct device_attribute *attr,
392 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
393 return sprintf(buf, "%d\n", indio_dev->buffer->scan_timestamp);
396 static ssize_t iio_scan_el_ts_store(struct device *dev,
397 struct device_attribute *attr,
402 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
405 ret = strtobool(buf, &state);
409 mutex_lock(&indio_dev->mlock);
410 if (iio_buffer_is_active(indio_dev->buffer)) {
414 indio_dev->buffer->scan_timestamp = state;
416 mutex_unlock(&indio_dev->mlock);
418 return ret ? ret : len;
421 static int iio_buffer_add_channel_sysfs(struct iio_dev *indio_dev,
422 const struct iio_chan_spec *chan)
424 int ret, attrcount = 0;
425 struct iio_buffer *buffer = indio_dev->buffer;
427 ret = __iio_add_chan_devattr("index",
429 &iio_show_scan_index,
434 &buffer->scan_el_dev_attr_list);
438 ret = __iio_add_chan_devattr("type",
440 &iio_show_fixed_type,
445 &buffer->scan_el_dev_attr_list);
449 if (chan->type != IIO_TIMESTAMP)
450 ret = __iio_add_chan_devattr("en",
457 &buffer->scan_el_dev_attr_list);
459 ret = __iio_add_chan_devattr("en",
461 &iio_scan_el_ts_show,
462 &iio_scan_el_ts_store,
466 &buffer->scan_el_dev_attr_list);
474 static ssize_t iio_buffer_read_length(struct device *dev,
475 struct device_attribute *attr,
478 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
479 struct iio_buffer *buffer = indio_dev->buffer;
481 return sprintf(buf, "%d\n", buffer->length);
484 static ssize_t iio_buffer_write_length(struct device *dev,
485 struct device_attribute *attr,
486 const char *buf, size_t len)
488 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
489 struct iio_buffer *buffer = indio_dev->buffer;
493 ret = kstrtouint(buf, 10, &val);
497 if (val == buffer->length)
500 mutex_lock(&indio_dev->mlock);
501 if (iio_buffer_is_active(indio_dev->buffer)) {
504 buffer->access->set_length(buffer, val);
509 if (buffer->length && buffer->length < buffer->watermark)
510 buffer->watermark = buffer->length;
512 mutex_unlock(&indio_dev->mlock);
514 return ret ? ret : len;
517 static ssize_t iio_buffer_show_enable(struct device *dev,
518 struct device_attribute *attr,
521 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
522 return sprintf(buf, "%d\n", iio_buffer_is_active(indio_dev->buffer));
525 static int iio_compute_scan_bytes(struct iio_dev *indio_dev,
526 const unsigned long *mask, bool timestamp)
528 const struct iio_chan_spec *ch;
530 int length, i, largest = 0;
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;
540 length = ch->scan_type.storagebits / 8;
541 bytes = ALIGN(bytes, length);
543 largest = max(largest, length);
546 ch = iio_find_channel_from_si(indio_dev,
547 indio_dev->scan_index_timestamp);
548 if (ch->scan_type.repeat > 1)
549 length = ch->scan_type.storagebits / 8 *
550 ch->scan_type.repeat;
552 length = ch->scan_type.storagebits / 8;
553 bytes = ALIGN(bytes, length);
555 largest = max(largest, length);
558 bytes = ALIGN(bytes, largest);
562 static void iio_buffer_activate(struct iio_dev *indio_dev,
563 struct iio_buffer *buffer)
565 iio_buffer_get(buffer);
566 list_add(&buffer->buffer_list, &indio_dev->buffer_list);
569 static void iio_buffer_deactivate(struct iio_buffer *buffer)
571 list_del_init(&buffer->buffer_list);
572 wake_up_interruptible(&buffer->pollq);
573 iio_buffer_put(buffer);
576 static void iio_buffer_deactivate_all(struct iio_dev *indio_dev)
578 struct iio_buffer *buffer, *_buffer;
580 list_for_each_entry_safe(buffer, _buffer,
581 &indio_dev->buffer_list, buffer_list)
582 iio_buffer_deactivate(buffer);
585 static void iio_buffer_update_bytes_per_datum(struct iio_dev *indio_dev,
586 struct iio_buffer *buffer)
590 if (!buffer->access->set_bytes_per_datum)
593 bytes = iio_compute_scan_bytes(indio_dev, buffer->scan_mask,
594 buffer->scan_timestamp);
596 buffer->access->set_bytes_per_datum(buffer, bytes);
599 static int iio_buffer_request_update(struct iio_dev *indio_dev,
600 struct iio_buffer *buffer)
604 iio_buffer_update_bytes_per_datum(indio_dev, buffer);
605 if (buffer->access->request_update) {
606 ret = buffer->access->request_update(buffer);
608 dev_dbg(&indio_dev->dev,
609 "Buffer not started: buffer parameter update failed (%d)\n",
618 static void iio_free_scan_mask(struct iio_dev *indio_dev,
619 const unsigned long *mask)
621 /* If the mask is dynamically allocated free it, otherwise do nothing */
622 if (!indio_dev->available_scan_masks)
626 struct iio_device_config {
628 const unsigned long *scan_mask;
629 unsigned int scan_bytes;
633 static int iio_verify_update(struct iio_dev *indio_dev,
634 struct iio_buffer *insert_buffer, struct iio_buffer *remove_buffer,
635 struct iio_device_config *config)
637 unsigned long *compound_mask;
638 const unsigned long *scan_mask;
639 bool strict_scanmask = false;
640 struct iio_buffer *buffer;
644 memset(config, 0, sizeof(*config));
647 * If there is just one buffer and we are removing it there is nothing
650 if (remove_buffer && !insert_buffer &&
651 list_is_singular(&indio_dev->buffer_list))
654 modes = indio_dev->modes;
656 list_for_each_entry(buffer, &indio_dev->buffer_list, buffer_list) {
657 if (buffer == remove_buffer)
659 modes &= buffer->access->modes;
663 modes &= insert_buffer->access->modes;
665 /* Definitely possible for devices to support both of these. */
666 if ((modes & INDIO_BUFFER_TRIGGERED) && indio_dev->trig) {
667 config->mode = INDIO_BUFFER_TRIGGERED;
668 } else if (modes & INDIO_BUFFER_HARDWARE) {
670 * Keep things simple for now and only allow a single buffer to
671 * be connected in hardware mode.
673 if (insert_buffer && !list_empty(&indio_dev->buffer_list))
675 config->mode = INDIO_BUFFER_HARDWARE;
676 strict_scanmask = true;
677 } else if (modes & INDIO_BUFFER_SOFTWARE) {
678 config->mode = INDIO_BUFFER_SOFTWARE;
680 /* Can only occur on first buffer */
681 if (indio_dev->modes & INDIO_BUFFER_TRIGGERED)
682 dev_dbg(&indio_dev->dev, "Buffer not started: no trigger\n");
686 /* What scan mask do we actually have? */
687 compound_mask = kcalloc(BITS_TO_LONGS(indio_dev->masklength),
688 sizeof(long), GFP_KERNEL);
689 if (compound_mask == NULL)
692 scan_timestamp = false;
694 list_for_each_entry(buffer, &indio_dev->buffer_list, buffer_list) {
695 if (buffer == remove_buffer)
697 bitmap_or(compound_mask, compound_mask, buffer->scan_mask,
698 indio_dev->masklength);
699 scan_timestamp |= buffer->scan_timestamp;
703 bitmap_or(compound_mask, compound_mask,
704 insert_buffer->scan_mask, indio_dev->masklength);
705 scan_timestamp |= insert_buffer->scan_timestamp;
708 if (indio_dev->available_scan_masks) {
709 scan_mask = iio_scan_mask_match(indio_dev->available_scan_masks,
710 indio_dev->masklength,
713 kfree(compound_mask);
714 if (scan_mask == NULL)
717 scan_mask = compound_mask;
720 config->scan_bytes = iio_compute_scan_bytes(indio_dev,
721 scan_mask, scan_timestamp);
722 config->scan_mask = scan_mask;
723 config->scan_timestamp = scan_timestamp;
728 static int iio_enable_buffers(struct iio_dev *indio_dev,
729 struct iio_device_config *config)
733 indio_dev->active_scan_mask = config->scan_mask;
734 indio_dev->scan_timestamp = config->scan_timestamp;
735 indio_dev->scan_bytes = config->scan_bytes;
737 iio_update_demux(indio_dev);
740 if (indio_dev->setup_ops->preenable) {
741 ret = indio_dev->setup_ops->preenable(indio_dev);
743 dev_dbg(&indio_dev->dev,
744 "Buffer not started: buffer preenable failed (%d)\n", ret);
745 goto err_undo_config;
749 if (indio_dev->info->update_scan_mode) {
750 ret = indio_dev->info
751 ->update_scan_mode(indio_dev,
752 indio_dev->active_scan_mask);
754 dev_dbg(&indio_dev->dev,
755 "Buffer not started: update scan mode failed (%d)\n",
757 goto err_run_postdisable;
761 indio_dev->currentmode = config->mode;
763 if (indio_dev->setup_ops->postenable) {
764 ret = indio_dev->setup_ops->postenable(indio_dev);
766 dev_dbg(&indio_dev->dev,
767 "Buffer not started: postenable failed (%d)\n", ret);
768 goto err_run_postdisable;
775 indio_dev->currentmode = INDIO_DIRECT_MODE;
776 if (indio_dev->setup_ops->postdisable)
777 indio_dev->setup_ops->postdisable(indio_dev);
779 indio_dev->active_scan_mask = NULL;
784 static int iio_disable_buffers(struct iio_dev *indio_dev)
789 /* Wind down existing buffers - iff there are any */
790 if (list_empty(&indio_dev->buffer_list))
794 * If things go wrong at some step in disable we still need to continue
795 * to perform the other steps, otherwise we leave the device in a
796 * inconsistent state. We return the error code for the first error we
800 if (indio_dev->setup_ops->predisable) {
801 ret2 = indio_dev->setup_ops->predisable(indio_dev);
806 indio_dev->currentmode = INDIO_DIRECT_MODE;
808 if (indio_dev->setup_ops->postdisable) {
809 ret2 = indio_dev->setup_ops->postdisable(indio_dev);
814 iio_free_scan_mask(indio_dev, indio_dev->active_scan_mask);
815 indio_dev->active_scan_mask = NULL;
820 static int __iio_update_buffers(struct iio_dev *indio_dev,
821 struct iio_buffer *insert_buffer,
822 struct iio_buffer *remove_buffer)
824 struct iio_device_config new_config;
827 ret = iio_verify_update(indio_dev, insert_buffer, remove_buffer,
833 ret = iio_buffer_request_update(indio_dev, insert_buffer);
835 goto err_free_config;
838 ret = iio_disable_buffers(indio_dev);
840 goto err_deactivate_all;
843 iio_buffer_deactivate(remove_buffer);
845 iio_buffer_activate(indio_dev, insert_buffer);
847 /* If no buffers in list, we are done */
848 if (list_empty(&indio_dev->buffer_list))
851 ret = iio_enable_buffers(indio_dev, &new_config);
853 goto err_deactivate_all;
859 * We've already verified that the config is valid earlier. If things go
860 * wrong in either enable or disable the most likely reason is an IO
861 * error from the device. In this case there is no good recovery
862 * strategy. Just make sure to disable everything and leave the device
863 * in a sane state. With a bit of luck the device might come back to
864 * life again later and userspace can try again.
866 iio_buffer_deactivate_all(indio_dev);
869 iio_free_scan_mask(indio_dev, new_config.scan_mask);
873 int iio_update_buffers(struct iio_dev *indio_dev,
874 struct iio_buffer *insert_buffer,
875 struct iio_buffer *remove_buffer)
879 if (insert_buffer == remove_buffer)
882 mutex_lock(&indio_dev->info_exist_lock);
883 mutex_lock(&indio_dev->mlock);
885 if (insert_buffer && iio_buffer_is_active(insert_buffer))
886 insert_buffer = NULL;
888 if (remove_buffer && !iio_buffer_is_active(remove_buffer))
889 remove_buffer = NULL;
891 if (!insert_buffer && !remove_buffer) {
896 if (indio_dev->info == NULL) {
901 ret = __iio_update_buffers(indio_dev, insert_buffer, remove_buffer);
904 mutex_unlock(&indio_dev->mlock);
905 mutex_unlock(&indio_dev->info_exist_lock);
909 EXPORT_SYMBOL_GPL(iio_update_buffers);
911 void iio_disable_all_buffers(struct iio_dev *indio_dev)
913 iio_disable_buffers(indio_dev);
914 iio_buffer_deactivate_all(indio_dev);
917 static ssize_t iio_buffer_store_enable(struct device *dev,
918 struct device_attribute *attr,
923 bool requested_state;
924 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
927 ret = strtobool(buf, &requested_state);
931 mutex_lock(&indio_dev->mlock);
933 /* Find out if it is in the list */
934 inlist = iio_buffer_is_active(indio_dev->buffer);
935 /* Already in desired state */
936 if (inlist == requested_state)
940 ret = __iio_update_buffers(indio_dev,
941 indio_dev->buffer, NULL);
943 ret = __iio_update_buffers(indio_dev,
944 NULL, indio_dev->buffer);
947 mutex_unlock(&indio_dev->mlock);
948 return (ret < 0) ? ret : len;
951 static const char * const iio_scan_elements_group_name = "scan_elements";
953 static ssize_t iio_buffer_show_watermark(struct device *dev,
954 struct device_attribute *attr,
957 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
958 struct iio_buffer *buffer = indio_dev->buffer;
960 return sprintf(buf, "%u\n", buffer->watermark);
963 static ssize_t iio_buffer_store_watermark(struct device *dev,
964 struct device_attribute *attr,
968 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
969 struct iio_buffer *buffer = indio_dev->buffer;
973 ret = kstrtouint(buf, 10, &val);
979 mutex_lock(&indio_dev->mlock);
981 if (val > buffer->length) {
986 if (iio_buffer_is_active(indio_dev->buffer)) {
991 buffer->watermark = val;
993 if (indio_dev->info->hwfifo_set_watermark)
994 indio_dev->info->hwfifo_set_watermark(indio_dev, val);
996 mutex_unlock(&indio_dev->mlock);
998 return ret ? ret : len;
1001 static DEVICE_ATTR(length, S_IRUGO | S_IWUSR, iio_buffer_read_length,
1002 iio_buffer_write_length);
1003 static struct device_attribute dev_attr_length_ro = __ATTR(length,
1004 S_IRUGO, iio_buffer_read_length, NULL);
1005 static DEVICE_ATTR(enable, S_IRUGO | S_IWUSR,
1006 iio_buffer_show_enable, iio_buffer_store_enable);
1007 static DEVICE_ATTR(watermark, S_IRUGO | S_IWUSR,
1008 iio_buffer_show_watermark, iio_buffer_store_watermark);
1010 static struct attribute *iio_buffer_attrs[] = {
1011 &dev_attr_length.attr,
1012 &dev_attr_enable.attr,
1013 &dev_attr_watermark.attr,
1016 int iio_buffer_alloc_sysfs_and_mask(struct iio_dev *indio_dev)
1018 struct iio_dev_attr *p;
1019 struct attribute **attr;
1020 struct iio_buffer *buffer = indio_dev->buffer;
1021 int ret, i, attrn, attrcount, attrcount_orig = 0;
1022 const struct iio_chan_spec *channels;
1024 channels = indio_dev->channels;
1026 int ml = indio_dev->masklength;
1028 for (i = 0; i < indio_dev->num_channels; i++)
1029 ml = max(ml, channels[i].scan_index + 1);
1030 indio_dev->masklength = ml;
1037 if (buffer->attrs) {
1038 while (buffer->attrs[attrcount] != NULL)
1042 attr = kcalloc(attrcount + ARRAY_SIZE(iio_buffer_attrs) + 1,
1043 sizeof(struct attribute *), GFP_KERNEL);
1047 memcpy(attr, iio_buffer_attrs, sizeof(iio_buffer_attrs));
1048 if (!buffer->access->set_length)
1049 attr[0] = &dev_attr_length_ro.attr;
1052 memcpy(&attr[ARRAY_SIZE(iio_buffer_attrs)], buffer->attrs,
1053 sizeof(struct attribute *) * attrcount);
1055 attr[attrcount + ARRAY_SIZE(iio_buffer_attrs)] = NULL;
1057 buffer->buffer_group.name = "buffer";
1058 buffer->buffer_group.attrs = attr;
1060 indio_dev->groups[indio_dev->groupcounter++] = &buffer->buffer_group;
1062 if (buffer->scan_el_attrs != NULL) {
1063 attr = buffer->scan_el_attrs->attrs;
1064 while (*attr++ != NULL)
1067 attrcount = attrcount_orig;
1068 INIT_LIST_HEAD(&buffer->scan_el_dev_attr_list);
1069 channels = indio_dev->channels;
1072 for (i = 0; i < indio_dev->num_channels; i++) {
1073 if (channels[i].scan_index < 0)
1076 ret = iio_buffer_add_channel_sysfs(indio_dev,
1079 goto error_cleanup_dynamic;
1081 if (channels[i].type == IIO_TIMESTAMP)
1082 indio_dev->scan_index_timestamp =
1083 channels[i].scan_index;
1085 if (indio_dev->masklength && buffer->scan_mask == NULL) {
1086 buffer->scan_mask = kcalloc(BITS_TO_LONGS(indio_dev->masklength),
1087 sizeof(*buffer->scan_mask),
1089 if (buffer->scan_mask == NULL) {
1091 goto error_cleanup_dynamic;
1096 buffer->scan_el_group.name = iio_scan_elements_group_name;
1098 buffer->scan_el_group.attrs = kcalloc(attrcount + 1,
1099 sizeof(buffer->scan_el_group.attrs[0]),
1101 if (buffer->scan_el_group.attrs == NULL) {
1103 goto error_free_scan_mask;
1105 if (buffer->scan_el_attrs)
1106 memcpy(buffer->scan_el_group.attrs, buffer->scan_el_attrs,
1107 sizeof(buffer->scan_el_group.attrs[0])*attrcount_orig);
1108 attrn = attrcount_orig;
1110 list_for_each_entry(p, &buffer->scan_el_dev_attr_list, l)
1111 buffer->scan_el_group.attrs[attrn++] = &p->dev_attr.attr;
1112 indio_dev->groups[indio_dev->groupcounter++] = &buffer->scan_el_group;
1116 error_free_scan_mask:
1117 kfree(buffer->scan_mask);
1118 error_cleanup_dynamic:
1119 iio_free_chan_devattr_list(&buffer->scan_el_dev_attr_list);
1120 kfree(indio_dev->buffer->buffer_group.attrs);
1125 void iio_buffer_free_sysfs_and_mask(struct iio_dev *indio_dev)
1127 if (!indio_dev->buffer)
1130 kfree(indio_dev->buffer->scan_mask);
1131 kfree(indio_dev->buffer->buffer_group.attrs);
1132 kfree(indio_dev->buffer->scan_el_group.attrs);
1133 iio_free_chan_devattr_list(&indio_dev->buffer->scan_el_dev_attr_list);
1137 * iio_validate_scan_mask_onehot() - Validates that exactly one channel is selected
1138 * @indio_dev: the iio device
1139 * @mask: scan mask to be checked
1141 * Return true if exactly one bit is set in the scan mask, false otherwise. It
1142 * can be used for devices where only one channel can be active for sampling at
1145 bool iio_validate_scan_mask_onehot(struct iio_dev *indio_dev,
1146 const unsigned long *mask)
1148 return bitmap_weight(mask, indio_dev->masklength) == 1;
1150 EXPORT_SYMBOL_GPL(iio_validate_scan_mask_onehot);
1152 int iio_scan_mask_query(struct iio_dev *indio_dev,
1153 struct iio_buffer *buffer, int bit)
1155 if (bit > indio_dev->masklength)
1158 if (!buffer->scan_mask)
1161 /* Ensure return value is 0 or 1. */
1162 return !!test_bit(bit, buffer->scan_mask);
1164 EXPORT_SYMBOL_GPL(iio_scan_mask_query);
1167 * struct iio_demux_table - table describing demux memcpy ops
1168 * @from: index to copy from
1169 * @to: index to copy to
1170 * @length: how many bytes to copy
1171 * @l: list head used for management
1173 struct iio_demux_table {
1180 static const void *iio_demux(struct iio_buffer *buffer,
1183 struct iio_demux_table *t;
1185 if (list_empty(&buffer->demux_list))
1187 list_for_each_entry(t, &buffer->demux_list, l)
1188 memcpy(buffer->demux_bounce + t->to,
1189 datain + t->from, t->length);
1191 return buffer->demux_bounce;
1194 static int iio_push_to_buffer(struct iio_buffer *buffer, const void *data)
1196 const void *dataout = iio_demux(buffer, data);
1199 ret = buffer->access->store_to(buffer, dataout);
1204 * We can't just test for watermark to decide if we wake the poll queue
1205 * because read may request less samples than the watermark.
1207 wake_up_interruptible_poll(&buffer->pollq, POLLIN | POLLRDNORM);
1211 static void iio_buffer_demux_free(struct iio_buffer *buffer)
1213 struct iio_demux_table *p, *q;
1214 list_for_each_entry_safe(p, q, &buffer->demux_list, l) {
1221 int iio_push_to_buffers(struct iio_dev *indio_dev, const void *data)
1224 struct iio_buffer *buf;
1226 list_for_each_entry(buf, &indio_dev->buffer_list, buffer_list) {
1227 ret = iio_push_to_buffer(buf, data);
1234 EXPORT_SYMBOL_GPL(iio_push_to_buffers);
1236 static int iio_buffer_add_demux(struct iio_buffer *buffer,
1237 struct iio_demux_table **p, unsigned int in_loc, unsigned int out_loc,
1238 unsigned int length)
1241 if (*p && (*p)->from + (*p)->length == in_loc &&
1242 (*p)->to + (*p)->length == out_loc) {
1243 (*p)->length += length;
1245 *p = kmalloc(sizeof(**p), GFP_KERNEL);
1248 (*p)->from = in_loc;
1250 (*p)->length = length;
1251 list_add_tail(&(*p)->l, &buffer->demux_list);
1257 static int iio_buffer_update_demux(struct iio_dev *indio_dev,
1258 struct iio_buffer *buffer)
1260 const struct iio_chan_spec *ch;
1261 int ret, in_ind = -1, out_ind, length;
1262 unsigned in_loc = 0, out_loc = 0;
1263 struct iio_demux_table *p = NULL;
1265 /* Clear out any old demux */
1266 iio_buffer_demux_free(buffer);
1267 kfree(buffer->demux_bounce);
1268 buffer->demux_bounce = NULL;
1270 /* First work out which scan mode we will actually have */
1271 if (bitmap_equal(indio_dev->active_scan_mask,
1273 indio_dev->masklength))
1276 /* Now we have the two masks, work from least sig and build up sizes */
1277 for_each_set_bit(out_ind,
1279 indio_dev->masklength) {
1280 in_ind = find_next_bit(indio_dev->active_scan_mask,
1281 indio_dev->masklength,
1283 while (in_ind != out_ind) {
1284 ch = iio_find_channel_from_si(indio_dev, in_ind);
1285 if (ch->scan_type.repeat > 1)
1286 length = ch->scan_type.storagebits / 8 *
1287 ch->scan_type.repeat;
1289 length = ch->scan_type.storagebits / 8;
1290 /* Make sure we are aligned */
1291 in_loc = roundup(in_loc, length) + length;
1292 in_ind = find_next_bit(indio_dev->active_scan_mask,
1293 indio_dev->masklength,
1296 ch = iio_find_channel_from_si(indio_dev, in_ind);
1297 if (ch->scan_type.repeat > 1)
1298 length = ch->scan_type.storagebits / 8 *
1299 ch->scan_type.repeat;
1301 length = ch->scan_type.storagebits / 8;
1302 out_loc = roundup(out_loc, length);
1303 in_loc = roundup(in_loc, length);
1304 ret = iio_buffer_add_demux(buffer, &p, in_loc, out_loc, length);
1306 goto error_clear_mux_table;
1310 /* Relies on scan_timestamp being last */
1311 if (buffer->scan_timestamp) {
1312 ch = iio_find_channel_from_si(indio_dev,
1313 indio_dev->scan_index_timestamp);
1314 if (ch->scan_type.repeat > 1)
1315 length = ch->scan_type.storagebits / 8 *
1316 ch->scan_type.repeat;
1318 length = ch->scan_type.storagebits / 8;
1319 out_loc = roundup(out_loc, length);
1320 in_loc = roundup(in_loc, length);
1321 ret = iio_buffer_add_demux(buffer, &p, in_loc, out_loc, length);
1323 goto error_clear_mux_table;
1327 buffer->demux_bounce = kzalloc(out_loc, GFP_KERNEL);
1328 if (buffer->demux_bounce == NULL) {
1330 goto error_clear_mux_table;
1334 error_clear_mux_table:
1335 iio_buffer_demux_free(buffer);
1340 int iio_update_demux(struct iio_dev *indio_dev)
1342 struct iio_buffer *buffer;
1345 list_for_each_entry(buffer, &indio_dev->buffer_list, buffer_list) {
1346 ret = iio_buffer_update_demux(indio_dev, buffer);
1348 goto error_clear_mux_table;
1352 error_clear_mux_table:
1353 list_for_each_entry(buffer, &indio_dev->buffer_list, buffer_list)
1354 iio_buffer_demux_free(buffer);
1358 EXPORT_SYMBOL_GPL(iio_update_demux);
1361 * iio_buffer_release() - Free a buffer's resources
1362 * @ref: Pointer to the kref embedded in the iio_buffer struct
1364 * This function is called when the last reference to the buffer has been
1365 * dropped. It will typically free all resources allocated by the buffer. Do not
1366 * call this function manually, always use iio_buffer_put() when done using a
1369 static void iio_buffer_release(struct kref *ref)
1371 struct iio_buffer *buffer = container_of(ref, struct iio_buffer, ref);
1373 buffer->access->release(buffer);
1377 * iio_buffer_get() - Grab a reference to the buffer
1378 * @buffer: The buffer to grab a reference for, may be NULL
1380 * Returns the pointer to the buffer that was passed into the function.
1382 struct iio_buffer *iio_buffer_get(struct iio_buffer *buffer)
1385 kref_get(&buffer->ref);
1389 EXPORT_SYMBOL_GPL(iio_buffer_get);
1392 * iio_buffer_put() - Release the reference to the buffer
1393 * @buffer: The buffer to release the reference for, may be NULL
1395 void iio_buffer_put(struct iio_buffer *buffer)
1398 kref_put(&buffer->ref, iio_buffer_release);
1400 EXPORT_SYMBOL_GPL(iio_buffer_put);