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;
114 if (!indio_dev->info)
117 if (!rb || !rb->access->read_first_n)
120 datum_size = rb->bytes_per_datum;
123 * If datum_size is 0 there will never be anything to read from the
124 * buffer, so signal end of file now.
129 if (filp->f_flags & O_NONBLOCK)
132 to_wait = min_t(size_t, n / datum_size, rb->watermark);
135 ret = wait_event_interruptible(rb->pollq,
136 iio_buffer_ready(indio_dev, rb, to_wait, n / datum_size));
140 if (!indio_dev->info)
143 ret = rb->access->read_first_n(rb, n, buf);
144 if (ret == 0 && (filp->f_flags & O_NONBLOCK))
152 * iio_buffer_poll() - poll the buffer to find out if it has data
153 * @filp: File structure pointer for device access
154 * @wait: Poll table structure pointer for which the driver adds
157 * Return: (POLLIN | POLLRDNORM) if data is available for reading
158 * or 0 for other cases
160 unsigned int iio_buffer_poll(struct file *filp,
161 struct poll_table_struct *wait)
163 struct iio_dev *indio_dev = filp->private_data;
164 struct iio_buffer *rb = indio_dev->buffer;
166 if (!indio_dev->info)
169 poll_wait(filp, &rb->pollq, wait);
170 if (iio_buffer_ready(indio_dev, rb, rb->watermark, 0))
171 return POLLIN | POLLRDNORM;
176 * iio_buffer_wakeup_poll - Wakes up the buffer waitqueue
177 * @indio_dev: The IIO device
179 * Wakes up the event waitqueue used for poll(). Should usually
180 * be called when the device is unregistered.
182 void iio_buffer_wakeup_poll(struct iio_dev *indio_dev)
184 if (!indio_dev->buffer)
187 wake_up(&indio_dev->buffer->pollq);
190 void iio_buffer_init(struct iio_buffer *buffer)
192 INIT_LIST_HEAD(&buffer->demux_list);
193 INIT_LIST_HEAD(&buffer->buffer_list);
194 init_waitqueue_head(&buffer->pollq);
195 kref_init(&buffer->ref);
196 if (!buffer->watermark)
197 buffer->watermark = 1;
199 EXPORT_SYMBOL(iio_buffer_init);
201 static ssize_t iio_show_scan_index(struct device *dev,
202 struct device_attribute *attr,
205 return sprintf(buf, "%u\n", to_iio_dev_attr(attr)->c->scan_index);
208 static ssize_t iio_show_fixed_type(struct device *dev,
209 struct device_attribute *attr,
212 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
213 u8 type = this_attr->c->scan_type.endianness;
215 if (type == IIO_CPU) {
216 #ifdef __LITTLE_ENDIAN
222 if (this_attr->c->scan_type.repeat > 1)
223 return sprintf(buf, "%s:%c%d/%dX%d>>%u\n",
224 iio_endian_prefix[type],
225 this_attr->c->scan_type.sign,
226 this_attr->c->scan_type.realbits,
227 this_attr->c->scan_type.storagebits,
228 this_attr->c->scan_type.repeat,
229 this_attr->c->scan_type.shift);
231 return sprintf(buf, "%s:%c%d/%d>>%u\n",
232 iio_endian_prefix[type],
233 this_attr->c->scan_type.sign,
234 this_attr->c->scan_type.realbits,
235 this_attr->c->scan_type.storagebits,
236 this_attr->c->scan_type.shift);
239 static ssize_t iio_scan_el_show(struct device *dev,
240 struct device_attribute *attr,
244 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
246 /* Ensure ret is 0 or 1. */
247 ret = !!test_bit(to_iio_dev_attr(attr)->address,
248 indio_dev->buffer->scan_mask);
250 return sprintf(buf, "%d\n", ret);
253 /* Note NULL used as error indicator as it doesn't make sense. */
254 static const unsigned long *iio_scan_mask_match(const unsigned long *av_masks,
255 unsigned int masklength,
256 const unsigned long *mask,
259 if (bitmap_empty(mask, masklength))
263 if (bitmap_equal(mask, av_masks, masklength))
266 if (bitmap_subset(mask, av_masks, masklength))
269 av_masks += BITS_TO_LONGS(masklength);
274 static bool iio_validate_scan_mask(struct iio_dev *indio_dev,
275 const unsigned long *mask)
277 if (!indio_dev->setup_ops->validate_scan_mask)
280 return indio_dev->setup_ops->validate_scan_mask(indio_dev, mask);
284 * iio_scan_mask_set() - set particular bit in the scan mask
285 * @indio_dev: the iio device
286 * @buffer: the buffer whose scan mask we are interested in
287 * @bit: the bit to be set.
289 * Note that at this point we have no way of knowing what other
290 * buffers might request, hence this code only verifies that the
291 * individual buffers request is plausible.
293 static int iio_scan_mask_set(struct iio_dev *indio_dev,
294 struct iio_buffer *buffer, int bit)
296 const unsigned long *mask;
297 unsigned long *trialmask;
299 trialmask = kmalloc(sizeof(*trialmask)*
300 BITS_TO_LONGS(indio_dev->masklength),
303 if (trialmask == NULL)
305 if (!indio_dev->masklength) {
306 WARN(1, "Trying to set scanmask prior to registering buffer\n");
307 goto err_invalid_mask;
309 bitmap_copy(trialmask, buffer->scan_mask, indio_dev->masklength);
310 set_bit(bit, trialmask);
312 if (!iio_validate_scan_mask(indio_dev, trialmask))
313 goto err_invalid_mask;
315 if (indio_dev->available_scan_masks) {
316 mask = iio_scan_mask_match(indio_dev->available_scan_masks,
317 indio_dev->masklength,
320 goto err_invalid_mask;
322 bitmap_copy(buffer->scan_mask, trialmask, indio_dev->masklength);
333 static int iio_scan_mask_clear(struct iio_buffer *buffer, int bit)
335 clear_bit(bit, buffer->scan_mask);
339 static ssize_t iio_scan_el_store(struct device *dev,
340 struct device_attribute *attr,
346 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
347 struct iio_buffer *buffer = indio_dev->buffer;
348 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
350 ret = strtobool(buf, &state);
353 mutex_lock(&indio_dev->mlock);
354 if (iio_buffer_is_active(indio_dev->buffer)) {
358 ret = iio_scan_mask_query(indio_dev, buffer, this_attr->address);
362 ret = iio_scan_mask_clear(buffer, this_attr->address);
365 } else if (state && !ret) {
366 ret = iio_scan_mask_set(indio_dev, buffer, this_attr->address);
372 mutex_unlock(&indio_dev->mlock);
374 return ret < 0 ? ret : len;
378 static ssize_t iio_scan_el_ts_show(struct device *dev,
379 struct device_attribute *attr,
382 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
383 return sprintf(buf, "%d\n", indio_dev->buffer->scan_timestamp);
386 static ssize_t iio_scan_el_ts_store(struct device *dev,
387 struct device_attribute *attr,
392 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
395 ret = strtobool(buf, &state);
399 mutex_lock(&indio_dev->mlock);
400 if (iio_buffer_is_active(indio_dev->buffer)) {
404 indio_dev->buffer->scan_timestamp = state;
406 mutex_unlock(&indio_dev->mlock);
408 return ret ? ret : len;
411 static int iio_buffer_add_channel_sysfs(struct iio_dev *indio_dev,
412 const struct iio_chan_spec *chan)
414 int ret, attrcount = 0;
415 struct iio_buffer *buffer = indio_dev->buffer;
417 ret = __iio_add_chan_devattr("index",
419 &iio_show_scan_index,
424 &buffer->scan_el_dev_attr_list);
428 ret = __iio_add_chan_devattr("type",
430 &iio_show_fixed_type,
435 &buffer->scan_el_dev_attr_list);
439 if (chan->type != IIO_TIMESTAMP)
440 ret = __iio_add_chan_devattr("en",
447 &buffer->scan_el_dev_attr_list);
449 ret = __iio_add_chan_devattr("en",
451 &iio_scan_el_ts_show,
452 &iio_scan_el_ts_store,
456 &buffer->scan_el_dev_attr_list);
464 static ssize_t iio_buffer_read_length(struct device *dev,
465 struct device_attribute *attr,
468 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
469 struct iio_buffer *buffer = indio_dev->buffer;
471 return sprintf(buf, "%d\n", buffer->length);
474 static ssize_t iio_buffer_write_length(struct device *dev,
475 struct device_attribute *attr,
476 const char *buf, size_t len)
478 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
479 struct iio_buffer *buffer = indio_dev->buffer;
483 ret = kstrtouint(buf, 10, &val);
487 if (val == buffer->length)
490 mutex_lock(&indio_dev->mlock);
491 if (iio_buffer_is_active(indio_dev->buffer)) {
494 buffer->access->set_length(buffer, val);
499 if (buffer->length && buffer->length < buffer->watermark)
500 buffer->watermark = buffer->length;
502 mutex_unlock(&indio_dev->mlock);
504 return ret ? ret : len;
507 static ssize_t iio_buffer_show_enable(struct device *dev,
508 struct device_attribute *attr,
511 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
512 return sprintf(buf, "%d\n", iio_buffer_is_active(indio_dev->buffer));
515 static unsigned int iio_storage_bytes_for_si(struct iio_dev *indio_dev,
516 unsigned int scan_index)
518 const struct iio_chan_spec *ch;
521 ch = iio_find_channel_from_si(indio_dev, scan_index);
522 bytes = ch->scan_type.storagebits / 8;
523 if (ch->scan_type.repeat > 1)
524 bytes *= ch->scan_type.repeat;
528 static unsigned int iio_storage_bytes_for_timestamp(struct iio_dev *indio_dev)
530 return iio_storage_bytes_for_si(indio_dev,
531 indio_dev->scan_index_timestamp);
534 static int iio_compute_scan_bytes(struct iio_dev *indio_dev,
535 const unsigned long *mask, bool timestamp)
540 /* How much space will the demuxed element take? */
541 for_each_set_bit(i, mask,
542 indio_dev->masklength) {
543 length = iio_storage_bytes_for_si(indio_dev, i);
544 bytes = ALIGN(bytes, length);
549 length = iio_storage_bytes_for_timestamp(indio_dev);
550 bytes = ALIGN(bytes, length);
556 static void iio_buffer_activate(struct iio_dev *indio_dev,
557 struct iio_buffer *buffer)
559 iio_buffer_get(buffer);
560 list_add(&buffer->buffer_list, &indio_dev->buffer_list);
563 static void iio_buffer_deactivate(struct iio_buffer *buffer)
565 list_del_init(&buffer->buffer_list);
566 wake_up_interruptible(&buffer->pollq);
567 iio_buffer_put(buffer);
570 static void iio_buffer_deactivate_all(struct iio_dev *indio_dev)
572 struct iio_buffer *buffer, *_buffer;
574 list_for_each_entry_safe(buffer, _buffer,
575 &indio_dev->buffer_list, buffer_list)
576 iio_buffer_deactivate(buffer);
579 static int iio_buffer_enable(struct iio_buffer *buffer,
580 struct iio_dev *indio_dev)
582 if (!buffer->access->enable)
584 return buffer->access->enable(buffer, indio_dev);
587 static int iio_buffer_disable(struct iio_buffer *buffer,
588 struct iio_dev *indio_dev)
590 if (!buffer->access->disable)
592 return buffer->access->disable(buffer, indio_dev);
595 static void iio_buffer_update_bytes_per_datum(struct iio_dev *indio_dev,
596 struct iio_buffer *buffer)
600 if (!buffer->access->set_bytes_per_datum)
603 bytes = iio_compute_scan_bytes(indio_dev, buffer->scan_mask,
604 buffer->scan_timestamp);
606 buffer->access->set_bytes_per_datum(buffer, bytes);
609 static int iio_buffer_request_update(struct iio_dev *indio_dev,
610 struct iio_buffer *buffer)
614 iio_buffer_update_bytes_per_datum(indio_dev, buffer);
615 if (buffer->access->request_update) {
616 ret = buffer->access->request_update(buffer);
618 dev_dbg(&indio_dev->dev,
619 "Buffer not started: buffer parameter update failed (%d)\n",
628 static void iio_free_scan_mask(struct iio_dev *indio_dev,
629 const unsigned long *mask)
631 /* If the mask is dynamically allocated free it, otherwise do nothing */
632 if (!indio_dev->available_scan_masks)
636 struct iio_device_config {
638 unsigned int watermark;
639 const unsigned long *scan_mask;
640 unsigned int scan_bytes;
644 static int iio_verify_update(struct iio_dev *indio_dev,
645 struct iio_buffer *insert_buffer, struct iio_buffer *remove_buffer,
646 struct iio_device_config *config)
648 unsigned long *compound_mask;
649 const unsigned long *scan_mask;
650 bool strict_scanmask = false;
651 struct iio_buffer *buffer;
655 memset(config, 0, sizeof(*config));
658 * If there is just one buffer and we are removing it there is nothing
661 if (remove_buffer && !insert_buffer &&
662 list_is_singular(&indio_dev->buffer_list))
665 modes = indio_dev->modes;
667 list_for_each_entry(buffer, &indio_dev->buffer_list, buffer_list) {
668 if (buffer == remove_buffer)
670 modes &= buffer->access->modes;
671 config->watermark = min(config->watermark, buffer->watermark);
675 modes &= insert_buffer->access->modes;
676 config->watermark = min(config->watermark,
677 insert_buffer->watermark);
680 /* Definitely possible for devices to support both of these. */
681 if ((modes & INDIO_BUFFER_TRIGGERED) && indio_dev->trig) {
682 config->mode = INDIO_BUFFER_TRIGGERED;
683 } else if (modes & INDIO_BUFFER_HARDWARE) {
685 * Keep things simple for now and only allow a single buffer to
686 * be connected in hardware mode.
688 if (insert_buffer && !list_empty(&indio_dev->buffer_list))
690 config->mode = INDIO_BUFFER_HARDWARE;
691 strict_scanmask = true;
692 } else if (modes & INDIO_BUFFER_SOFTWARE) {
693 config->mode = INDIO_BUFFER_SOFTWARE;
695 /* Can only occur on first buffer */
696 if (indio_dev->modes & INDIO_BUFFER_TRIGGERED)
697 dev_dbg(&indio_dev->dev, "Buffer not started: no trigger\n");
701 /* What scan mask do we actually have? */
702 compound_mask = kcalloc(BITS_TO_LONGS(indio_dev->masklength),
703 sizeof(long), GFP_KERNEL);
704 if (compound_mask == NULL)
707 scan_timestamp = false;
709 list_for_each_entry(buffer, &indio_dev->buffer_list, buffer_list) {
710 if (buffer == remove_buffer)
712 bitmap_or(compound_mask, compound_mask, buffer->scan_mask,
713 indio_dev->masklength);
714 scan_timestamp |= buffer->scan_timestamp;
718 bitmap_or(compound_mask, compound_mask,
719 insert_buffer->scan_mask, indio_dev->masklength);
720 scan_timestamp |= insert_buffer->scan_timestamp;
723 if (indio_dev->available_scan_masks) {
724 scan_mask = iio_scan_mask_match(indio_dev->available_scan_masks,
725 indio_dev->masklength,
728 kfree(compound_mask);
729 if (scan_mask == NULL)
732 scan_mask = compound_mask;
735 config->scan_bytes = iio_compute_scan_bytes(indio_dev,
736 scan_mask, scan_timestamp);
737 config->scan_mask = scan_mask;
738 config->scan_timestamp = scan_timestamp;
743 static int iio_enable_buffers(struct iio_dev *indio_dev,
744 struct iio_device_config *config)
746 struct iio_buffer *buffer;
749 indio_dev->active_scan_mask = config->scan_mask;
750 indio_dev->scan_timestamp = config->scan_timestamp;
751 indio_dev->scan_bytes = config->scan_bytes;
753 iio_update_demux(indio_dev);
756 if (indio_dev->setup_ops->preenable) {
757 ret = indio_dev->setup_ops->preenable(indio_dev);
759 dev_dbg(&indio_dev->dev,
760 "Buffer not started: buffer preenable failed (%d)\n", ret);
761 goto err_undo_config;
765 if (indio_dev->info->update_scan_mode) {
766 ret = indio_dev->info
767 ->update_scan_mode(indio_dev,
768 indio_dev->active_scan_mask);
770 dev_dbg(&indio_dev->dev,
771 "Buffer not started: update scan mode failed (%d)\n",
773 goto err_run_postdisable;
777 if (indio_dev->info->hwfifo_set_watermark)
778 indio_dev->info->hwfifo_set_watermark(indio_dev,
781 list_for_each_entry(buffer, &indio_dev->buffer_list, buffer_list) {
782 ret = iio_buffer_enable(buffer, indio_dev);
784 goto err_disable_buffers;
787 indio_dev->currentmode = config->mode;
789 if (indio_dev->setup_ops->postenable) {
790 ret = indio_dev->setup_ops->postenable(indio_dev);
792 dev_dbg(&indio_dev->dev,
793 "Buffer not started: postenable failed (%d)\n", ret);
794 goto err_disable_buffers;
801 list_for_each_entry_continue_reverse(buffer, &indio_dev->buffer_list,
803 iio_buffer_disable(buffer, indio_dev);
805 indio_dev->currentmode = INDIO_DIRECT_MODE;
806 if (indio_dev->setup_ops->postdisable)
807 indio_dev->setup_ops->postdisable(indio_dev);
809 indio_dev->active_scan_mask = NULL;
814 static int iio_disable_buffers(struct iio_dev *indio_dev)
816 struct iio_buffer *buffer;
820 /* Wind down existing buffers - iff there are any */
821 if (list_empty(&indio_dev->buffer_list))
825 * If things go wrong at some step in disable we still need to continue
826 * to perform the other steps, otherwise we leave the device in a
827 * inconsistent state. We return the error code for the first error we
831 if (indio_dev->setup_ops->predisable) {
832 ret2 = indio_dev->setup_ops->predisable(indio_dev);
837 list_for_each_entry(buffer, &indio_dev->buffer_list, buffer_list) {
838 ret2 = iio_buffer_disable(buffer, indio_dev);
843 indio_dev->currentmode = INDIO_DIRECT_MODE;
845 if (indio_dev->setup_ops->postdisable) {
846 ret2 = indio_dev->setup_ops->postdisable(indio_dev);
851 iio_free_scan_mask(indio_dev, indio_dev->active_scan_mask);
852 indio_dev->active_scan_mask = NULL;
857 static int __iio_update_buffers(struct iio_dev *indio_dev,
858 struct iio_buffer *insert_buffer,
859 struct iio_buffer *remove_buffer)
861 struct iio_device_config new_config;
864 ret = iio_verify_update(indio_dev, insert_buffer, remove_buffer,
870 ret = iio_buffer_request_update(indio_dev, insert_buffer);
872 goto err_free_config;
875 ret = iio_disable_buffers(indio_dev);
877 goto err_deactivate_all;
880 iio_buffer_deactivate(remove_buffer);
882 iio_buffer_activate(indio_dev, insert_buffer);
884 /* If no buffers in list, we are done */
885 if (list_empty(&indio_dev->buffer_list))
888 ret = iio_enable_buffers(indio_dev, &new_config);
890 goto err_deactivate_all;
896 * We've already verified that the config is valid earlier. If things go
897 * wrong in either enable or disable the most likely reason is an IO
898 * error from the device. In this case there is no good recovery
899 * strategy. Just make sure to disable everything and leave the device
900 * in a sane state. With a bit of luck the device might come back to
901 * life again later and userspace can try again.
903 iio_buffer_deactivate_all(indio_dev);
906 iio_free_scan_mask(indio_dev, new_config.scan_mask);
910 int iio_update_buffers(struct iio_dev *indio_dev,
911 struct iio_buffer *insert_buffer,
912 struct iio_buffer *remove_buffer)
916 if (insert_buffer == remove_buffer)
919 mutex_lock(&indio_dev->info_exist_lock);
920 mutex_lock(&indio_dev->mlock);
922 if (insert_buffer && iio_buffer_is_active(insert_buffer))
923 insert_buffer = NULL;
925 if (remove_buffer && !iio_buffer_is_active(remove_buffer))
926 remove_buffer = NULL;
928 if (!insert_buffer && !remove_buffer) {
933 if (indio_dev->info == NULL) {
938 ret = __iio_update_buffers(indio_dev, insert_buffer, remove_buffer);
941 mutex_unlock(&indio_dev->mlock);
942 mutex_unlock(&indio_dev->info_exist_lock);
946 EXPORT_SYMBOL_GPL(iio_update_buffers);
948 void iio_disable_all_buffers(struct iio_dev *indio_dev)
950 iio_disable_buffers(indio_dev);
951 iio_buffer_deactivate_all(indio_dev);
954 static ssize_t iio_buffer_store_enable(struct device *dev,
955 struct device_attribute *attr,
960 bool requested_state;
961 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
964 ret = strtobool(buf, &requested_state);
968 mutex_lock(&indio_dev->mlock);
970 /* Find out if it is in the list */
971 inlist = iio_buffer_is_active(indio_dev->buffer);
972 /* Already in desired state */
973 if (inlist == requested_state)
977 ret = __iio_update_buffers(indio_dev,
978 indio_dev->buffer, NULL);
980 ret = __iio_update_buffers(indio_dev,
981 NULL, indio_dev->buffer);
984 mutex_unlock(&indio_dev->mlock);
985 return (ret < 0) ? ret : len;
988 static const char * const iio_scan_elements_group_name = "scan_elements";
990 static ssize_t iio_buffer_show_watermark(struct device *dev,
991 struct device_attribute *attr,
994 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
995 struct iio_buffer *buffer = indio_dev->buffer;
997 return sprintf(buf, "%u\n", buffer->watermark);
1000 static ssize_t iio_buffer_store_watermark(struct device *dev,
1001 struct device_attribute *attr,
1005 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
1006 struct iio_buffer *buffer = indio_dev->buffer;
1010 ret = kstrtouint(buf, 10, &val);
1016 mutex_lock(&indio_dev->mlock);
1018 if (val > buffer->length) {
1023 if (iio_buffer_is_active(indio_dev->buffer)) {
1028 buffer->watermark = val;
1030 mutex_unlock(&indio_dev->mlock);
1032 return ret ? ret : len;
1035 static DEVICE_ATTR(length, S_IRUGO | S_IWUSR, iio_buffer_read_length,
1036 iio_buffer_write_length);
1037 static struct device_attribute dev_attr_length_ro = __ATTR(length,
1038 S_IRUGO, iio_buffer_read_length, NULL);
1039 static DEVICE_ATTR(enable, S_IRUGO | S_IWUSR,
1040 iio_buffer_show_enable, iio_buffer_store_enable);
1041 static DEVICE_ATTR(watermark, S_IRUGO | S_IWUSR,
1042 iio_buffer_show_watermark, iio_buffer_store_watermark);
1043 static struct device_attribute dev_attr_watermark_ro = __ATTR(watermark,
1044 S_IRUGO, iio_buffer_show_watermark, NULL);
1046 static struct attribute *iio_buffer_attrs[] = {
1047 &dev_attr_length.attr,
1048 &dev_attr_enable.attr,
1049 &dev_attr_watermark.attr,
1052 int iio_buffer_alloc_sysfs_and_mask(struct iio_dev *indio_dev)
1054 struct iio_dev_attr *p;
1055 struct attribute **attr;
1056 struct iio_buffer *buffer = indio_dev->buffer;
1057 int ret, i, attrn, attrcount, attrcount_orig = 0;
1058 const struct iio_chan_spec *channels;
1060 channels = indio_dev->channels;
1062 int ml = indio_dev->masklength;
1064 for (i = 0; i < indio_dev->num_channels; i++)
1065 ml = max(ml, channels[i].scan_index + 1);
1066 indio_dev->masklength = ml;
1073 if (buffer->attrs) {
1074 while (buffer->attrs[attrcount] != NULL)
1078 attr = kcalloc(attrcount + ARRAY_SIZE(iio_buffer_attrs) + 1,
1079 sizeof(struct attribute *), GFP_KERNEL);
1083 memcpy(attr, iio_buffer_attrs, sizeof(iio_buffer_attrs));
1084 if (!buffer->access->set_length)
1085 attr[0] = &dev_attr_length_ro.attr;
1087 if (buffer->access->flags & INDIO_BUFFER_FLAG_FIXED_WATERMARK)
1088 attr[2] = &dev_attr_watermark_ro.attr;
1091 memcpy(&attr[ARRAY_SIZE(iio_buffer_attrs)], buffer->attrs,
1092 sizeof(struct attribute *) * attrcount);
1094 attr[attrcount + ARRAY_SIZE(iio_buffer_attrs)] = NULL;
1096 buffer->buffer_group.name = "buffer";
1097 buffer->buffer_group.attrs = attr;
1099 indio_dev->groups[indio_dev->groupcounter++] = &buffer->buffer_group;
1101 if (buffer->scan_el_attrs != NULL) {
1102 attr = buffer->scan_el_attrs->attrs;
1103 while (*attr++ != NULL)
1106 attrcount = attrcount_orig;
1107 INIT_LIST_HEAD(&buffer->scan_el_dev_attr_list);
1108 channels = indio_dev->channels;
1111 for (i = 0; i < indio_dev->num_channels; i++) {
1112 if (channels[i].scan_index < 0)
1115 ret = iio_buffer_add_channel_sysfs(indio_dev,
1118 goto error_cleanup_dynamic;
1120 if (channels[i].type == IIO_TIMESTAMP)
1121 indio_dev->scan_index_timestamp =
1122 channels[i].scan_index;
1124 if (indio_dev->masklength && buffer->scan_mask == NULL) {
1125 buffer->scan_mask = kcalloc(BITS_TO_LONGS(indio_dev->masklength),
1126 sizeof(*buffer->scan_mask),
1128 if (buffer->scan_mask == NULL) {
1130 goto error_cleanup_dynamic;
1135 buffer->scan_el_group.name = iio_scan_elements_group_name;
1137 buffer->scan_el_group.attrs = kcalloc(attrcount + 1,
1138 sizeof(buffer->scan_el_group.attrs[0]),
1140 if (buffer->scan_el_group.attrs == NULL) {
1142 goto error_free_scan_mask;
1144 if (buffer->scan_el_attrs)
1145 memcpy(buffer->scan_el_group.attrs, buffer->scan_el_attrs,
1146 sizeof(buffer->scan_el_group.attrs[0])*attrcount_orig);
1147 attrn = attrcount_orig;
1149 list_for_each_entry(p, &buffer->scan_el_dev_attr_list, l)
1150 buffer->scan_el_group.attrs[attrn++] = &p->dev_attr.attr;
1151 indio_dev->groups[indio_dev->groupcounter++] = &buffer->scan_el_group;
1155 error_free_scan_mask:
1156 kfree(buffer->scan_mask);
1157 error_cleanup_dynamic:
1158 iio_free_chan_devattr_list(&buffer->scan_el_dev_attr_list);
1159 kfree(indio_dev->buffer->buffer_group.attrs);
1164 void iio_buffer_free_sysfs_and_mask(struct iio_dev *indio_dev)
1166 if (!indio_dev->buffer)
1169 kfree(indio_dev->buffer->scan_mask);
1170 kfree(indio_dev->buffer->buffer_group.attrs);
1171 kfree(indio_dev->buffer->scan_el_group.attrs);
1172 iio_free_chan_devattr_list(&indio_dev->buffer->scan_el_dev_attr_list);
1176 * iio_validate_scan_mask_onehot() - Validates that exactly one channel is selected
1177 * @indio_dev: the iio device
1178 * @mask: scan mask to be checked
1180 * Return true if exactly one bit is set in the scan mask, false otherwise. It
1181 * can be used for devices where only one channel can be active for sampling at
1184 bool iio_validate_scan_mask_onehot(struct iio_dev *indio_dev,
1185 const unsigned long *mask)
1187 return bitmap_weight(mask, indio_dev->masklength) == 1;
1189 EXPORT_SYMBOL_GPL(iio_validate_scan_mask_onehot);
1191 int iio_scan_mask_query(struct iio_dev *indio_dev,
1192 struct iio_buffer *buffer, int bit)
1194 if (bit > indio_dev->masklength)
1197 if (!buffer->scan_mask)
1200 /* Ensure return value is 0 or 1. */
1201 return !!test_bit(bit, buffer->scan_mask);
1203 EXPORT_SYMBOL_GPL(iio_scan_mask_query);
1206 * struct iio_demux_table - table describing demux memcpy ops
1207 * @from: index to copy from
1208 * @to: index to copy to
1209 * @length: how many bytes to copy
1210 * @l: list head used for management
1212 struct iio_demux_table {
1219 static const void *iio_demux(struct iio_buffer *buffer,
1222 struct iio_demux_table *t;
1224 if (list_empty(&buffer->demux_list))
1226 list_for_each_entry(t, &buffer->demux_list, l)
1227 memcpy(buffer->demux_bounce + t->to,
1228 datain + t->from, t->length);
1230 return buffer->demux_bounce;
1233 static int iio_push_to_buffer(struct iio_buffer *buffer, const void *data)
1235 const void *dataout = iio_demux(buffer, data);
1238 ret = buffer->access->store_to(buffer, dataout);
1243 * We can't just test for watermark to decide if we wake the poll queue
1244 * because read may request less samples than the watermark.
1246 wake_up_interruptible_poll(&buffer->pollq, POLLIN | POLLRDNORM);
1250 static void iio_buffer_demux_free(struct iio_buffer *buffer)
1252 struct iio_demux_table *p, *q;
1253 list_for_each_entry_safe(p, q, &buffer->demux_list, l) {
1260 int iio_push_to_buffers(struct iio_dev *indio_dev, const void *data)
1263 struct iio_buffer *buf;
1265 list_for_each_entry(buf, &indio_dev->buffer_list, buffer_list) {
1266 ret = iio_push_to_buffer(buf, data);
1273 EXPORT_SYMBOL_GPL(iio_push_to_buffers);
1275 static int iio_buffer_add_demux(struct iio_buffer *buffer,
1276 struct iio_demux_table **p, unsigned int in_loc, unsigned int out_loc,
1277 unsigned int length)
1280 if (*p && (*p)->from + (*p)->length == in_loc &&
1281 (*p)->to + (*p)->length == out_loc) {
1282 (*p)->length += length;
1284 *p = kmalloc(sizeof(**p), GFP_KERNEL);
1287 (*p)->from = in_loc;
1289 (*p)->length = length;
1290 list_add_tail(&(*p)->l, &buffer->demux_list);
1296 static int iio_buffer_update_demux(struct iio_dev *indio_dev,
1297 struct iio_buffer *buffer)
1299 int ret, in_ind = -1, out_ind, length;
1300 unsigned in_loc = 0, out_loc = 0;
1301 struct iio_demux_table *p = NULL;
1303 /* Clear out any old demux */
1304 iio_buffer_demux_free(buffer);
1305 kfree(buffer->demux_bounce);
1306 buffer->demux_bounce = NULL;
1308 /* First work out which scan mode we will actually have */
1309 if (bitmap_equal(indio_dev->active_scan_mask,
1311 indio_dev->masklength))
1314 /* Now we have the two masks, work from least sig and build up sizes */
1315 for_each_set_bit(out_ind,
1317 indio_dev->masklength) {
1318 in_ind = find_next_bit(indio_dev->active_scan_mask,
1319 indio_dev->masklength,
1321 while (in_ind != out_ind) {
1322 in_ind = find_next_bit(indio_dev->active_scan_mask,
1323 indio_dev->masklength,
1325 length = iio_storage_bytes_for_si(indio_dev, in_ind);
1326 /* Make sure we are aligned */
1327 in_loc = roundup(in_loc, length) + length;
1329 length = iio_storage_bytes_for_si(indio_dev, in_ind);
1330 out_loc = roundup(out_loc, length);
1331 in_loc = roundup(in_loc, length);
1332 ret = iio_buffer_add_demux(buffer, &p, in_loc, out_loc, length);
1334 goto error_clear_mux_table;
1338 /* Relies on scan_timestamp being last */
1339 if (buffer->scan_timestamp) {
1340 length = iio_storage_bytes_for_timestamp(indio_dev);
1341 out_loc = roundup(out_loc, length);
1342 in_loc = roundup(in_loc, length);
1343 ret = iio_buffer_add_demux(buffer, &p, in_loc, out_loc, length);
1345 goto error_clear_mux_table;
1349 buffer->demux_bounce = kzalloc(out_loc, GFP_KERNEL);
1350 if (buffer->demux_bounce == NULL) {
1352 goto error_clear_mux_table;
1356 error_clear_mux_table:
1357 iio_buffer_demux_free(buffer);
1362 int iio_update_demux(struct iio_dev *indio_dev)
1364 struct iio_buffer *buffer;
1367 list_for_each_entry(buffer, &indio_dev->buffer_list, buffer_list) {
1368 ret = iio_buffer_update_demux(indio_dev, buffer);
1370 goto error_clear_mux_table;
1374 error_clear_mux_table:
1375 list_for_each_entry(buffer, &indio_dev->buffer_list, buffer_list)
1376 iio_buffer_demux_free(buffer);
1380 EXPORT_SYMBOL_GPL(iio_update_demux);
1383 * iio_buffer_release() - Free a buffer's resources
1384 * @ref: Pointer to the kref embedded in the iio_buffer struct
1386 * This function is called when the last reference to the buffer has been
1387 * dropped. It will typically free all resources allocated by the buffer. Do not
1388 * call this function manually, always use iio_buffer_put() when done using a
1391 static void iio_buffer_release(struct kref *ref)
1393 struct iio_buffer *buffer = container_of(ref, struct iio_buffer, ref);
1395 buffer->access->release(buffer);
1399 * iio_buffer_get() - Grab a reference to the buffer
1400 * @buffer: The buffer to grab a reference for, may be NULL
1402 * Returns the pointer to the buffer that was passed into the function.
1404 struct iio_buffer *iio_buffer_get(struct iio_buffer *buffer)
1407 kref_get(&buffer->ref);
1411 EXPORT_SYMBOL_GPL(iio_buffer_get);
1414 * iio_buffer_put() - Release the reference to the buffer
1415 * @buffer: The buffer to release the reference for, may be NULL
1417 void iio_buffer_put(struct iio_buffer *buffer)
1420 kref_put(&buffer->ref, iio_buffer_release);
1422 EXPORT_SYMBOL_GPL(iio_buffer_put);