summaryrefslogtreecommitdiffstats
path: root/drivers/iio/industrialio-buffer.c
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/iio/industrialio-buffer.c')
-rw-r--r--drivers/iio/industrialio-buffer.c2007
1 files changed, 2007 insertions, 0 deletions
diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio-buffer.c
new file mode 100644
index 0000000000..176d31d9f9
--- /dev/null
+++ b/drivers/iio/industrialio-buffer.c
@@ -0,0 +1,2007 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* The industrial I/O core
+ *
+ * Copyright (c) 2008 Jonathan Cameron
+ *
+ * Handling of buffer allocation / resizing.
+ *
+ * Things to look at here.
+ * - Better memory allocation techniques?
+ * - Alternative access techniques?
+ */
+#include <linux/anon_inodes.h>
+#include <linux/kernel.h>
+#include <linux/export.h>
+#include <linux/device.h>
+#include <linux/file.h>
+#include <linux/fs.h>
+#include <linux/cdev.h>
+#include <linux/slab.h>
+#include <linux/poll.h>
+#include <linux/sched/signal.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/iio-opaque.h>
+#include "iio_core.h"
+#include "iio_core_trigger.h"
+#include <linux/iio/sysfs.h>
+#include <linux/iio/buffer.h>
+#include <linux/iio/buffer_impl.h>
+
+static const char * const iio_endian_prefix[] = {
+ [IIO_BE] = "be",
+ [IIO_LE] = "le",
+};
+
+static bool iio_buffer_is_active(struct iio_buffer *buf)
+{
+ return !list_empty(&buf->buffer_list);
+}
+
+static size_t iio_buffer_data_available(struct iio_buffer *buf)
+{
+ return buf->access->data_available(buf);
+}
+
+static int iio_buffer_flush_hwfifo(struct iio_dev *indio_dev,
+ struct iio_buffer *buf, size_t required)
+{
+ if (!indio_dev->info->hwfifo_flush_to_buffer)
+ return -ENODEV;
+
+ return indio_dev->info->hwfifo_flush_to_buffer(indio_dev, required);
+}
+
+static bool iio_buffer_ready(struct iio_dev *indio_dev, struct iio_buffer *buf,
+ size_t to_wait, int to_flush)
+{
+ size_t avail;
+ int flushed = 0;
+
+ /* wakeup if the device was unregistered */
+ if (!indio_dev->info)
+ return true;
+
+ /* drain the buffer if it was disabled */
+ if (!iio_buffer_is_active(buf)) {
+ to_wait = min_t(size_t, to_wait, 1);
+ to_flush = 0;
+ }
+
+ avail = iio_buffer_data_available(buf);
+
+ if (avail >= to_wait) {
+ /* force a flush for non-blocking reads */
+ if (!to_wait && avail < to_flush)
+ iio_buffer_flush_hwfifo(indio_dev, buf,
+ to_flush - avail);
+ return true;
+ }
+
+ if (to_flush)
+ flushed = iio_buffer_flush_hwfifo(indio_dev, buf,
+ to_wait - avail);
+ if (flushed <= 0)
+ return false;
+
+ if (avail + flushed >= to_wait)
+ return true;
+
+ return false;
+}
+
+/**
+ * iio_buffer_read() - chrdev read for buffer access
+ * @filp: File structure pointer for the char device
+ * @buf: Destination buffer for iio buffer read
+ * @n: First n bytes to read
+ * @f_ps: Long offset provided by the user as a seek position
+ *
+ * This function relies on all buffer implementations having an
+ * iio_buffer as their first element.
+ *
+ * Return: negative values corresponding to error codes or ret != 0
+ * for ending the reading activity
+ **/
+static ssize_t iio_buffer_read(struct file *filp, char __user *buf,
+ size_t n, loff_t *f_ps)
+{
+ struct iio_dev_buffer_pair *ib = filp->private_data;
+ struct iio_buffer *rb = ib->buffer;
+ struct iio_dev *indio_dev = ib->indio_dev;
+ DEFINE_WAIT_FUNC(wait, woken_wake_function);
+ size_t datum_size;
+ size_t to_wait;
+ int ret = 0;
+
+ if (!indio_dev->info)
+ return -ENODEV;
+
+ if (!rb || !rb->access->read)
+ return -EINVAL;
+
+ if (rb->direction != IIO_BUFFER_DIRECTION_IN)
+ return -EPERM;
+
+ datum_size = rb->bytes_per_datum;
+
+ /*
+ * If datum_size is 0 there will never be anything to read from the
+ * buffer, so signal end of file now.
+ */
+ if (!datum_size)
+ return 0;
+
+ if (filp->f_flags & O_NONBLOCK)
+ to_wait = 0;
+ else
+ to_wait = min_t(size_t, n / datum_size, rb->watermark);
+
+ add_wait_queue(&rb->pollq, &wait);
+ do {
+ if (!indio_dev->info) {
+ ret = -ENODEV;
+ break;
+ }
+
+ if (!iio_buffer_ready(indio_dev, rb, to_wait, n / datum_size)) {
+ if (signal_pending(current)) {
+ ret = -ERESTARTSYS;
+ break;
+ }
+
+ wait_woken(&wait, TASK_INTERRUPTIBLE,
+ MAX_SCHEDULE_TIMEOUT);
+ continue;
+ }
+
+ ret = rb->access->read(rb, n, buf);
+ if (ret == 0 && (filp->f_flags & O_NONBLOCK))
+ ret = -EAGAIN;
+ } while (ret == 0);
+ remove_wait_queue(&rb->pollq, &wait);
+
+ return ret;
+}
+
+static size_t iio_buffer_space_available(struct iio_buffer *buf)
+{
+ if (buf->access->space_available)
+ return buf->access->space_available(buf);
+
+ return SIZE_MAX;
+}
+
+static ssize_t iio_buffer_write(struct file *filp, const char __user *buf,
+ size_t n, loff_t *f_ps)
+{
+ struct iio_dev_buffer_pair *ib = filp->private_data;
+ struct iio_buffer *rb = ib->buffer;
+ struct iio_dev *indio_dev = ib->indio_dev;
+ DEFINE_WAIT_FUNC(wait, woken_wake_function);
+ int ret = 0;
+ size_t written;
+
+ if (!indio_dev->info)
+ return -ENODEV;
+
+ if (!rb || !rb->access->write)
+ return -EINVAL;
+
+ if (rb->direction != IIO_BUFFER_DIRECTION_OUT)
+ return -EPERM;
+
+ written = 0;
+ add_wait_queue(&rb->pollq, &wait);
+ do {
+ if (!indio_dev->info)
+ return -ENODEV;
+
+ if (!iio_buffer_space_available(rb)) {
+ if (signal_pending(current)) {
+ ret = -ERESTARTSYS;
+ break;
+ }
+
+ if (filp->f_flags & O_NONBLOCK) {
+ if (!written)
+ ret = -EAGAIN;
+ break;
+ }
+
+ wait_woken(&wait, TASK_INTERRUPTIBLE,
+ MAX_SCHEDULE_TIMEOUT);
+ continue;
+ }
+
+ ret = rb->access->write(rb, n - written, buf + written);
+ if (ret < 0)
+ break;
+
+ written += ret;
+
+ } while (written != n);
+ remove_wait_queue(&rb->pollq, &wait);
+
+ return ret < 0 ? ret : written;
+}
+
+/**
+ * iio_buffer_poll() - poll the buffer to find out if it has data
+ * @filp: File structure pointer for device access
+ * @wait: Poll table structure pointer for which the driver adds
+ * a wait queue
+ *
+ * Return: (EPOLLIN | EPOLLRDNORM) if data is available for reading
+ * or 0 for other cases
+ */
+static __poll_t iio_buffer_poll(struct file *filp,
+ struct poll_table_struct *wait)
+{
+ struct iio_dev_buffer_pair *ib = filp->private_data;
+ struct iio_buffer *rb = ib->buffer;
+ struct iio_dev *indio_dev = ib->indio_dev;
+
+ if (!indio_dev->info || !rb)
+ return 0;
+
+ poll_wait(filp, &rb->pollq, wait);
+
+ switch (rb->direction) {
+ case IIO_BUFFER_DIRECTION_IN:
+ if (iio_buffer_ready(indio_dev, rb, rb->watermark, 0))
+ return EPOLLIN | EPOLLRDNORM;
+ break;
+ case IIO_BUFFER_DIRECTION_OUT:
+ if (iio_buffer_space_available(rb))
+ return EPOLLOUT | EPOLLWRNORM;
+ break;
+ }
+
+ return 0;
+}
+
+ssize_t iio_buffer_read_wrapper(struct file *filp, char __user *buf,
+ size_t n, loff_t *f_ps)
+{
+ struct iio_dev_buffer_pair *ib = filp->private_data;
+ struct iio_buffer *rb = ib->buffer;
+
+ /* check if buffer was opened through new API */
+ if (test_bit(IIO_BUSY_BIT_POS, &rb->flags))
+ return -EBUSY;
+
+ return iio_buffer_read(filp, buf, n, f_ps);
+}
+
+ssize_t iio_buffer_write_wrapper(struct file *filp, const char __user *buf,
+ size_t n, loff_t *f_ps)
+{
+ struct iio_dev_buffer_pair *ib = filp->private_data;
+ struct iio_buffer *rb = ib->buffer;
+
+ /* check if buffer was opened through new API */
+ if (test_bit(IIO_BUSY_BIT_POS, &rb->flags))
+ return -EBUSY;
+
+ return iio_buffer_write(filp, buf, n, f_ps);
+}
+
+__poll_t iio_buffer_poll_wrapper(struct file *filp,
+ struct poll_table_struct *wait)
+{
+ struct iio_dev_buffer_pair *ib = filp->private_data;
+ struct iio_buffer *rb = ib->buffer;
+
+ /* check if buffer was opened through new API */
+ if (test_bit(IIO_BUSY_BIT_POS, &rb->flags))
+ return 0;
+
+ return iio_buffer_poll(filp, wait);
+}
+
+/**
+ * iio_buffer_wakeup_poll - Wakes up the buffer waitqueue
+ * @indio_dev: The IIO device
+ *
+ * Wakes up the event waitqueue used for poll(). Should usually
+ * be called when the device is unregistered.
+ */
+void iio_buffer_wakeup_poll(struct iio_dev *indio_dev)
+{
+ struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
+ struct iio_buffer *buffer;
+ unsigned int i;
+
+ for (i = 0; i < iio_dev_opaque->attached_buffers_cnt; i++) {
+ buffer = iio_dev_opaque->attached_buffers[i];
+ wake_up(&buffer->pollq);
+ }
+}
+
+int iio_pop_from_buffer(struct iio_buffer *buffer, void *data)
+{
+ if (!buffer || !buffer->access || !buffer->access->remove_from)
+ return -EINVAL;
+
+ return buffer->access->remove_from(buffer, data);
+}
+EXPORT_SYMBOL_GPL(iio_pop_from_buffer);
+
+void iio_buffer_init(struct iio_buffer *buffer)
+{
+ INIT_LIST_HEAD(&buffer->demux_list);
+ INIT_LIST_HEAD(&buffer->buffer_list);
+ init_waitqueue_head(&buffer->pollq);
+ kref_init(&buffer->ref);
+ if (!buffer->watermark)
+ buffer->watermark = 1;
+}
+EXPORT_SYMBOL(iio_buffer_init);
+
+void iio_device_detach_buffers(struct iio_dev *indio_dev)
+{
+ struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
+ struct iio_buffer *buffer;
+ unsigned int i;
+
+ for (i = 0; i < iio_dev_opaque->attached_buffers_cnt; i++) {
+ buffer = iio_dev_opaque->attached_buffers[i];
+ iio_buffer_put(buffer);
+ }
+
+ kfree(iio_dev_opaque->attached_buffers);
+}
+
+static ssize_t iio_show_scan_index(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ return sysfs_emit(buf, "%u\n", to_iio_dev_attr(attr)->c->scan_index);
+}
+
+static ssize_t iio_show_fixed_type(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
+ u8 type = this_attr->c->scan_type.endianness;
+
+ if (type == IIO_CPU) {
+#ifdef __LITTLE_ENDIAN
+ type = IIO_LE;
+#else
+ type = IIO_BE;
+#endif
+ }
+ if (this_attr->c->scan_type.repeat > 1)
+ return sysfs_emit(buf, "%s:%c%d/%dX%d>>%u\n",
+ iio_endian_prefix[type],
+ this_attr->c->scan_type.sign,
+ this_attr->c->scan_type.realbits,
+ this_attr->c->scan_type.storagebits,
+ this_attr->c->scan_type.repeat,
+ this_attr->c->scan_type.shift);
+ else
+ return sysfs_emit(buf, "%s:%c%d/%d>>%u\n",
+ iio_endian_prefix[type],
+ this_attr->c->scan_type.sign,
+ this_attr->c->scan_type.realbits,
+ this_attr->c->scan_type.storagebits,
+ this_attr->c->scan_type.shift);
+}
+
+static ssize_t iio_scan_el_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ int ret;
+ struct iio_buffer *buffer = to_iio_dev_attr(attr)->buffer;
+
+ /* Ensure ret is 0 or 1. */
+ ret = !!test_bit(to_iio_dev_attr(attr)->address,
+ buffer->scan_mask);
+
+ return sysfs_emit(buf, "%d\n", ret);
+}
+
+/* Note NULL used as error indicator as it doesn't make sense. */
+static const unsigned long *iio_scan_mask_match(const unsigned long *av_masks,
+ unsigned int masklength,
+ const unsigned long *mask,
+ bool strict)
+{
+ if (bitmap_empty(mask, masklength))
+ return NULL;
+ while (*av_masks) {
+ if (strict) {
+ if (bitmap_equal(mask, av_masks, masklength))
+ return av_masks;
+ } else {
+ if (bitmap_subset(mask, av_masks, masklength))
+ return av_masks;
+ }
+ av_masks += BITS_TO_LONGS(masklength);
+ }
+ return NULL;
+}
+
+static bool iio_validate_scan_mask(struct iio_dev *indio_dev,
+ const unsigned long *mask)
+{
+ if (!indio_dev->setup_ops->validate_scan_mask)
+ return true;
+
+ return indio_dev->setup_ops->validate_scan_mask(indio_dev, mask);
+}
+
+/**
+ * iio_scan_mask_set() - set particular bit in the scan mask
+ * @indio_dev: the iio device
+ * @buffer: the buffer whose scan mask we are interested in
+ * @bit: the bit to be set.
+ *
+ * Note that at this point we have no way of knowing what other
+ * buffers might request, hence this code only verifies that the
+ * individual buffers request is plausible.
+ */
+static int iio_scan_mask_set(struct iio_dev *indio_dev,
+ struct iio_buffer *buffer, int bit)
+{
+ const unsigned long *mask;
+ unsigned long *trialmask;
+
+ if (!indio_dev->masklength) {
+ WARN(1, "Trying to set scanmask prior to registering buffer\n");
+ return -EINVAL;
+ }
+
+ trialmask = bitmap_alloc(indio_dev->masklength, GFP_KERNEL);
+ if (!trialmask)
+ return -ENOMEM;
+ bitmap_copy(trialmask, buffer->scan_mask, indio_dev->masklength);
+ set_bit(bit, trialmask);
+
+ if (!iio_validate_scan_mask(indio_dev, trialmask))
+ goto err_invalid_mask;
+
+ if (indio_dev->available_scan_masks) {
+ mask = iio_scan_mask_match(indio_dev->available_scan_masks,
+ indio_dev->masklength,
+ trialmask, false);
+ if (!mask)
+ goto err_invalid_mask;
+ }
+ bitmap_copy(buffer->scan_mask, trialmask, indio_dev->masklength);
+
+ bitmap_free(trialmask);
+
+ return 0;
+
+err_invalid_mask:
+ bitmap_free(trialmask);
+ return -EINVAL;
+}
+
+static int iio_scan_mask_clear(struct iio_buffer *buffer, int bit)
+{
+ clear_bit(bit, buffer->scan_mask);
+ return 0;
+}
+
+static int iio_scan_mask_query(struct iio_dev *indio_dev,
+ struct iio_buffer *buffer, int bit)
+{
+ if (bit > indio_dev->masklength)
+ return -EINVAL;
+
+ if (!buffer->scan_mask)
+ return 0;
+
+ /* Ensure return value is 0 or 1. */
+ return !!test_bit(bit, buffer->scan_mask);
+};
+
+static ssize_t iio_scan_el_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf,
+ size_t len)
+{
+ int ret;
+ bool state;
+ struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+ struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
+ struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
+ struct iio_buffer *buffer = this_attr->buffer;
+
+ ret = kstrtobool(buf, &state);
+ if (ret < 0)
+ return ret;
+ mutex_lock(&iio_dev_opaque->mlock);
+ if (iio_buffer_is_active(buffer)) {
+ ret = -EBUSY;
+ goto error_ret;
+ }
+ ret = iio_scan_mask_query(indio_dev, buffer, this_attr->address);
+ if (ret < 0)
+ goto error_ret;
+ if (!state && ret) {
+ ret = iio_scan_mask_clear(buffer, this_attr->address);
+ if (ret)
+ goto error_ret;
+ } else if (state && !ret) {
+ ret = iio_scan_mask_set(indio_dev, buffer, this_attr->address);
+ if (ret)
+ goto error_ret;
+ }
+
+error_ret:
+ mutex_unlock(&iio_dev_opaque->mlock);
+
+ return ret < 0 ? ret : len;
+}
+
+static ssize_t iio_scan_el_ts_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct iio_buffer *buffer = to_iio_dev_attr(attr)->buffer;
+
+ return sysfs_emit(buf, "%d\n", buffer->scan_timestamp);
+}
+
+static ssize_t iio_scan_el_ts_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf,
+ size_t len)
+{
+ int ret;
+ struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+ struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
+ struct iio_buffer *buffer = to_iio_dev_attr(attr)->buffer;
+ bool state;
+
+ ret = kstrtobool(buf, &state);
+ if (ret < 0)
+ return ret;
+
+ mutex_lock(&iio_dev_opaque->mlock);
+ if (iio_buffer_is_active(buffer)) {
+ ret = -EBUSY;
+ goto error_ret;
+ }
+ buffer->scan_timestamp = state;
+error_ret:
+ mutex_unlock(&iio_dev_opaque->mlock);
+
+ return ret ? ret : len;
+}
+
+static int iio_buffer_add_channel_sysfs(struct iio_dev *indio_dev,
+ struct iio_buffer *buffer,
+ const struct iio_chan_spec *chan)
+{
+ int ret, attrcount = 0;
+
+ ret = __iio_add_chan_devattr("index",
+ chan,
+ &iio_show_scan_index,
+ NULL,
+ 0,
+ IIO_SEPARATE,
+ &indio_dev->dev,
+ buffer,
+ &buffer->buffer_attr_list);
+ if (ret)
+ return ret;
+ attrcount++;
+ ret = __iio_add_chan_devattr("type",
+ chan,
+ &iio_show_fixed_type,
+ NULL,
+ 0,
+ 0,
+ &indio_dev->dev,
+ buffer,
+ &buffer->buffer_attr_list);
+ if (ret)
+ return ret;
+ attrcount++;
+ if (chan->type != IIO_TIMESTAMP)
+ ret = __iio_add_chan_devattr("en",
+ chan,
+ &iio_scan_el_show,
+ &iio_scan_el_store,
+ chan->scan_index,
+ 0,
+ &indio_dev->dev,
+ buffer,
+ &buffer->buffer_attr_list);
+ else
+ ret = __iio_add_chan_devattr("en",
+ chan,
+ &iio_scan_el_ts_show,
+ &iio_scan_el_ts_store,
+ chan->scan_index,
+ 0,
+ &indio_dev->dev,
+ buffer,
+ &buffer->buffer_attr_list);
+ if (ret)
+ return ret;
+ attrcount++;
+ ret = attrcount;
+ return ret;
+}
+
+static ssize_t length_show(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ struct iio_buffer *buffer = to_iio_dev_attr(attr)->buffer;
+
+ return sysfs_emit(buf, "%d\n", buffer->length);
+}
+
+static ssize_t length_store(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t len)
+{
+ struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+ struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
+ struct iio_buffer *buffer = to_iio_dev_attr(attr)->buffer;
+ unsigned int val;
+ int ret;
+
+ ret = kstrtouint(buf, 10, &val);
+ if (ret)
+ return ret;
+
+ if (val == buffer->length)
+ return len;
+
+ mutex_lock(&iio_dev_opaque->mlock);
+ if (iio_buffer_is_active(buffer)) {
+ ret = -EBUSY;
+ } else {
+ buffer->access->set_length(buffer, val);
+ ret = 0;
+ }
+ if (ret)
+ goto out;
+ if (buffer->length && buffer->length < buffer->watermark)
+ buffer->watermark = buffer->length;
+out:
+ mutex_unlock(&iio_dev_opaque->mlock);
+
+ return ret ? ret : len;
+}
+
+static ssize_t enable_show(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ struct iio_buffer *buffer = to_iio_dev_attr(attr)->buffer;
+
+ return sysfs_emit(buf, "%d\n", iio_buffer_is_active(buffer));
+}
+
+static unsigned int iio_storage_bytes_for_si(struct iio_dev *indio_dev,
+ unsigned int scan_index)
+{
+ const struct iio_chan_spec *ch;
+ unsigned int bytes;
+
+ ch = iio_find_channel_from_si(indio_dev, scan_index);
+ bytes = ch->scan_type.storagebits / 8;
+ if (ch->scan_type.repeat > 1)
+ bytes *= ch->scan_type.repeat;
+ return bytes;
+}
+
+static unsigned int iio_storage_bytes_for_timestamp(struct iio_dev *indio_dev)
+{
+ struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
+
+ return iio_storage_bytes_for_si(indio_dev,
+ iio_dev_opaque->scan_index_timestamp);
+}
+
+static int iio_compute_scan_bytes(struct iio_dev *indio_dev,
+ const unsigned long *mask, bool timestamp)
+{
+ unsigned int bytes = 0;
+ int length, i, largest = 0;
+
+ /* How much space will the demuxed element take? */
+ for_each_set_bit(i, mask,
+ indio_dev->masklength) {
+ length = iio_storage_bytes_for_si(indio_dev, i);
+ bytes = ALIGN(bytes, length);
+ bytes += length;
+ largest = max(largest, length);
+ }
+
+ if (timestamp) {
+ length = iio_storage_bytes_for_timestamp(indio_dev);
+ bytes = ALIGN(bytes, length);
+ bytes += length;
+ largest = max(largest, length);
+ }
+
+ bytes = ALIGN(bytes, largest);
+ return bytes;
+}
+
+static void iio_buffer_activate(struct iio_dev *indio_dev,
+ struct iio_buffer *buffer)
+{
+ struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
+
+ iio_buffer_get(buffer);
+ list_add(&buffer->buffer_list, &iio_dev_opaque->buffer_list);
+}
+
+static void iio_buffer_deactivate(struct iio_buffer *buffer)
+{
+ list_del_init(&buffer->buffer_list);
+ wake_up_interruptible(&buffer->pollq);
+ iio_buffer_put(buffer);
+}
+
+static void iio_buffer_deactivate_all(struct iio_dev *indio_dev)
+{
+ struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
+ struct iio_buffer *buffer, *_buffer;
+
+ list_for_each_entry_safe(buffer, _buffer,
+ &iio_dev_opaque->buffer_list, buffer_list)
+ iio_buffer_deactivate(buffer);
+}
+
+static int iio_buffer_enable(struct iio_buffer *buffer,
+ struct iio_dev *indio_dev)
+{
+ if (!buffer->access->enable)
+ return 0;
+ return buffer->access->enable(buffer, indio_dev);
+}
+
+static int iio_buffer_disable(struct iio_buffer *buffer,
+ struct iio_dev *indio_dev)
+{
+ if (!buffer->access->disable)
+ return 0;
+ return buffer->access->disable(buffer, indio_dev);
+}
+
+static void iio_buffer_update_bytes_per_datum(struct iio_dev *indio_dev,
+ struct iio_buffer *buffer)
+{
+ unsigned int bytes;
+
+ if (!buffer->access->set_bytes_per_datum)
+ return;
+
+ bytes = iio_compute_scan_bytes(indio_dev, buffer->scan_mask,
+ buffer->scan_timestamp);
+
+ buffer->access->set_bytes_per_datum(buffer, bytes);
+}
+
+static int iio_buffer_request_update(struct iio_dev *indio_dev,
+ struct iio_buffer *buffer)
+{
+ int ret;
+
+ iio_buffer_update_bytes_per_datum(indio_dev, buffer);
+ if (buffer->access->request_update) {
+ ret = buffer->access->request_update(buffer);
+ if (ret) {
+ dev_dbg(&indio_dev->dev,
+ "Buffer not started: buffer parameter update failed (%d)\n",
+ ret);
+ return ret;
+ }
+ }
+
+ return 0;
+}
+
+static void iio_free_scan_mask(struct iio_dev *indio_dev,
+ const unsigned long *mask)
+{
+ /* If the mask is dynamically allocated free it, otherwise do nothing */
+ if (!indio_dev->available_scan_masks)
+ bitmap_free(mask);
+}
+
+struct iio_device_config {
+ unsigned int mode;
+ unsigned int watermark;
+ const unsigned long *scan_mask;
+ unsigned int scan_bytes;
+ bool scan_timestamp;
+};
+
+static int iio_verify_update(struct iio_dev *indio_dev,
+ struct iio_buffer *insert_buffer,
+ struct iio_buffer *remove_buffer,
+ struct iio_device_config *config)
+{
+ struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
+ unsigned long *compound_mask;
+ const unsigned long *scan_mask;
+ bool strict_scanmask = false;
+ struct iio_buffer *buffer;
+ bool scan_timestamp;
+ unsigned int modes;
+
+ if (insert_buffer &&
+ bitmap_empty(insert_buffer->scan_mask, indio_dev->masklength)) {
+ dev_dbg(&indio_dev->dev,
+ "At least one scan element must be enabled first\n");
+ return -EINVAL;
+ }
+
+ memset(config, 0, sizeof(*config));
+ config->watermark = ~0;
+
+ /*
+ * If there is just one buffer and we are removing it there is nothing
+ * to verify.
+ */
+ if (remove_buffer && !insert_buffer &&
+ list_is_singular(&iio_dev_opaque->buffer_list))
+ return 0;
+
+ modes = indio_dev->modes;
+
+ list_for_each_entry(buffer, &iio_dev_opaque->buffer_list, buffer_list) {
+ if (buffer == remove_buffer)
+ continue;
+ modes &= buffer->access->modes;
+ config->watermark = min(config->watermark, buffer->watermark);
+ }
+
+ if (insert_buffer) {
+ modes &= insert_buffer->access->modes;
+ config->watermark = min(config->watermark,
+ insert_buffer->watermark);
+ }
+
+ /* Definitely possible for devices to support both of these. */
+ if ((modes & INDIO_BUFFER_TRIGGERED) && indio_dev->trig) {
+ config->mode = INDIO_BUFFER_TRIGGERED;
+ } else if (modes & INDIO_BUFFER_HARDWARE) {
+ /*
+ * Keep things simple for now and only allow a single buffer to
+ * be connected in hardware mode.
+ */
+ if (insert_buffer && !list_empty(&iio_dev_opaque->buffer_list))
+ return -EINVAL;
+ config->mode = INDIO_BUFFER_HARDWARE;
+ strict_scanmask = true;
+ } else if (modes & INDIO_BUFFER_SOFTWARE) {
+ config->mode = INDIO_BUFFER_SOFTWARE;
+ } else {
+ /* Can only occur on first buffer */
+ if (indio_dev->modes & INDIO_BUFFER_TRIGGERED)
+ dev_dbg(&indio_dev->dev, "Buffer not started: no trigger\n");
+ return -EINVAL;
+ }
+
+ /* What scan mask do we actually have? */
+ compound_mask = bitmap_zalloc(indio_dev->masklength, GFP_KERNEL);
+ if (!compound_mask)
+ return -ENOMEM;
+
+ scan_timestamp = false;
+
+ list_for_each_entry(buffer, &iio_dev_opaque->buffer_list, buffer_list) {
+ if (buffer == remove_buffer)
+ continue;
+ bitmap_or(compound_mask, compound_mask, buffer->scan_mask,
+ indio_dev->masklength);
+ scan_timestamp |= buffer->scan_timestamp;
+ }
+
+ if (insert_buffer) {
+ bitmap_or(compound_mask, compound_mask,
+ insert_buffer->scan_mask, indio_dev->masklength);
+ scan_timestamp |= insert_buffer->scan_timestamp;
+ }
+
+ if (indio_dev->available_scan_masks) {
+ scan_mask = iio_scan_mask_match(indio_dev->available_scan_masks,
+ indio_dev->masklength,
+ compound_mask,
+ strict_scanmask);
+ bitmap_free(compound_mask);
+ if (!scan_mask)
+ return -EINVAL;
+ } else {
+ scan_mask = compound_mask;
+ }
+
+ config->scan_bytes = iio_compute_scan_bytes(indio_dev,
+ scan_mask, scan_timestamp);
+ config->scan_mask = scan_mask;
+ config->scan_timestamp = scan_timestamp;
+
+ return 0;
+}
+
+/**
+ * struct iio_demux_table - table describing demux memcpy ops
+ * @from: index to copy from
+ * @to: index to copy to
+ * @length: how many bytes to copy
+ * @l: list head used for management
+ */
+struct iio_demux_table {
+ unsigned int from;
+ unsigned int to;
+ unsigned int length;
+ struct list_head l;
+};
+
+static void iio_buffer_demux_free(struct iio_buffer *buffer)
+{
+ struct iio_demux_table *p, *q;
+
+ list_for_each_entry_safe(p, q, &buffer->demux_list, l) {
+ list_del(&p->l);
+ kfree(p);
+ }
+}
+
+static int iio_buffer_add_demux(struct iio_buffer *buffer,
+ struct iio_demux_table **p, unsigned int in_loc,
+ unsigned int out_loc,
+ unsigned int length)
+{
+ if (*p && (*p)->from + (*p)->length == in_loc &&
+ (*p)->to + (*p)->length == out_loc) {
+ (*p)->length += length;
+ } else {
+ *p = kmalloc(sizeof(**p), GFP_KERNEL);
+ if (!(*p))
+ return -ENOMEM;
+ (*p)->from = in_loc;
+ (*p)->to = out_loc;
+ (*p)->length = length;
+ list_add_tail(&(*p)->l, &buffer->demux_list);
+ }
+
+ return 0;
+}
+
+static int iio_buffer_update_demux(struct iio_dev *indio_dev,
+ struct iio_buffer *buffer)
+{
+ int ret, in_ind = -1, out_ind, length;
+ unsigned int in_loc = 0, out_loc = 0;
+ struct iio_demux_table *p = NULL;
+
+ /* Clear out any old demux */
+ iio_buffer_demux_free(buffer);
+ kfree(buffer->demux_bounce);
+ buffer->demux_bounce = NULL;
+
+ /* First work out which scan mode we will actually have */
+ if (bitmap_equal(indio_dev->active_scan_mask,
+ buffer->scan_mask,
+ indio_dev->masklength))
+ return 0;
+
+ /* Now we have the two masks, work from least sig and build up sizes */
+ for_each_set_bit(out_ind,
+ buffer->scan_mask,
+ indio_dev->masklength) {
+ in_ind = find_next_bit(indio_dev->active_scan_mask,
+ indio_dev->masklength,
+ in_ind + 1);
+ while (in_ind != out_ind) {
+ length = iio_storage_bytes_for_si(indio_dev, in_ind);
+ /* Make sure we are aligned */
+ in_loc = roundup(in_loc, length) + length;
+ in_ind = find_next_bit(indio_dev->active_scan_mask,
+ indio_dev->masklength,
+ in_ind + 1);
+ }
+ length = iio_storage_bytes_for_si(indio_dev, in_ind);
+ out_loc = roundup(out_loc, length);
+ in_loc = roundup(in_loc, length);
+ ret = iio_buffer_add_demux(buffer, &p, in_loc, out_loc, length);
+ if (ret)
+ goto error_clear_mux_table;
+ out_loc += length;
+ in_loc += length;
+ }
+ /* Relies on scan_timestamp being last */
+ if (buffer->scan_timestamp) {
+ length = iio_storage_bytes_for_timestamp(indio_dev);
+ out_loc = roundup(out_loc, length);
+ in_loc = roundup(in_loc, length);
+ ret = iio_buffer_add_demux(buffer, &p, in_loc, out_loc, length);
+ if (ret)
+ goto error_clear_mux_table;
+ out_loc += length;
+ }
+ buffer->demux_bounce = kzalloc(out_loc, GFP_KERNEL);
+ if (!buffer->demux_bounce) {
+ ret = -ENOMEM;
+ goto error_clear_mux_table;
+ }
+ return 0;
+
+error_clear_mux_table:
+ iio_buffer_demux_free(buffer);
+
+ return ret;
+}
+
+static int iio_update_demux(struct iio_dev *indio_dev)
+{
+ struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
+ struct iio_buffer *buffer;
+ int ret;
+
+ list_for_each_entry(buffer, &iio_dev_opaque->buffer_list, buffer_list) {
+ ret = iio_buffer_update_demux(indio_dev, buffer);
+ if (ret < 0)
+ goto error_clear_mux_table;
+ }
+ return 0;
+
+error_clear_mux_table:
+ list_for_each_entry(buffer, &iio_dev_opaque->buffer_list, buffer_list)
+ iio_buffer_demux_free(buffer);
+
+ return ret;
+}
+
+static int iio_enable_buffers(struct iio_dev *indio_dev,
+ struct iio_device_config *config)
+{
+ struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
+ struct iio_buffer *buffer, *tmp = NULL;
+ int ret;
+
+ indio_dev->active_scan_mask = config->scan_mask;
+ indio_dev->scan_timestamp = config->scan_timestamp;
+ indio_dev->scan_bytes = config->scan_bytes;
+ iio_dev_opaque->currentmode = config->mode;
+
+ iio_update_demux(indio_dev);
+
+ /* Wind up again */
+ if (indio_dev->setup_ops->preenable) {
+ ret = indio_dev->setup_ops->preenable(indio_dev);
+ if (ret) {
+ dev_dbg(&indio_dev->dev,
+ "Buffer not started: buffer preenable failed (%d)\n", ret);
+ goto err_undo_config;
+ }
+ }
+
+ if (indio_dev->info->update_scan_mode) {
+ ret = indio_dev->info
+ ->update_scan_mode(indio_dev,
+ indio_dev->active_scan_mask);
+ if (ret < 0) {
+ dev_dbg(&indio_dev->dev,
+ "Buffer not started: update scan mode failed (%d)\n",
+ ret);
+ goto err_run_postdisable;
+ }
+ }
+
+ if (indio_dev->info->hwfifo_set_watermark)
+ indio_dev->info->hwfifo_set_watermark(indio_dev,
+ config->watermark);
+
+ list_for_each_entry(buffer, &iio_dev_opaque->buffer_list, buffer_list) {
+ ret = iio_buffer_enable(buffer, indio_dev);
+ if (ret) {
+ tmp = buffer;
+ goto err_disable_buffers;
+ }
+ }
+
+ if (iio_dev_opaque->currentmode == INDIO_BUFFER_TRIGGERED) {
+ ret = iio_trigger_attach_poll_func(indio_dev->trig,
+ indio_dev->pollfunc);
+ if (ret)
+ goto err_disable_buffers;
+ }
+
+ if (indio_dev->setup_ops->postenable) {
+ ret = indio_dev->setup_ops->postenable(indio_dev);
+ if (ret) {
+ dev_dbg(&indio_dev->dev,
+ "Buffer not started: postenable failed (%d)\n", ret);
+ goto err_detach_pollfunc;
+ }
+ }
+
+ return 0;
+
+err_detach_pollfunc:
+ if (iio_dev_opaque->currentmode == INDIO_BUFFER_TRIGGERED) {
+ iio_trigger_detach_poll_func(indio_dev->trig,
+ indio_dev->pollfunc);
+ }
+err_disable_buffers:
+ buffer = list_prepare_entry(tmp, &iio_dev_opaque->buffer_list, buffer_list);
+ list_for_each_entry_continue_reverse(buffer, &iio_dev_opaque->buffer_list,
+ buffer_list)
+ iio_buffer_disable(buffer, indio_dev);
+err_run_postdisable:
+ if (indio_dev->setup_ops->postdisable)
+ indio_dev->setup_ops->postdisable(indio_dev);
+err_undo_config:
+ iio_dev_opaque->currentmode = INDIO_DIRECT_MODE;
+ indio_dev->active_scan_mask = NULL;
+
+ return ret;
+}
+
+static int iio_disable_buffers(struct iio_dev *indio_dev)
+{
+ struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
+ struct iio_buffer *buffer;
+ int ret = 0;
+ int ret2;
+
+ /* Wind down existing buffers - iff there are any */
+ if (list_empty(&iio_dev_opaque->buffer_list))
+ return 0;
+
+ /*
+ * If things go wrong at some step in disable we still need to continue
+ * to perform the other steps, otherwise we leave the device in a
+ * inconsistent state. We return the error code for the first error we
+ * encountered.
+ */
+
+ if (indio_dev->setup_ops->predisable) {
+ ret2 = indio_dev->setup_ops->predisable(indio_dev);
+ if (ret2 && !ret)
+ ret = ret2;
+ }
+
+ if (iio_dev_opaque->currentmode == INDIO_BUFFER_TRIGGERED) {
+ iio_trigger_detach_poll_func(indio_dev->trig,
+ indio_dev->pollfunc);
+ }
+
+ list_for_each_entry(buffer, &iio_dev_opaque->buffer_list, buffer_list) {
+ ret2 = iio_buffer_disable(buffer, indio_dev);
+ if (ret2 && !ret)
+ ret = ret2;
+ }
+
+ if (indio_dev->setup_ops->postdisable) {
+ ret2 = indio_dev->setup_ops->postdisable(indio_dev);
+ if (ret2 && !ret)
+ ret = ret2;
+ }
+
+ iio_free_scan_mask(indio_dev, indio_dev->active_scan_mask);
+ indio_dev->active_scan_mask = NULL;
+ iio_dev_opaque->currentmode = INDIO_DIRECT_MODE;
+
+ return ret;
+}
+
+static int __iio_update_buffers(struct iio_dev *indio_dev,
+ struct iio_buffer *insert_buffer,
+ struct iio_buffer *remove_buffer)
+{
+ struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
+ struct iio_device_config new_config;
+ int ret;
+
+ ret = iio_verify_update(indio_dev, insert_buffer, remove_buffer,
+ &new_config);
+ if (ret)
+ return ret;
+
+ if (insert_buffer) {
+ ret = iio_buffer_request_update(indio_dev, insert_buffer);
+ if (ret)
+ goto err_free_config;
+ }
+
+ ret = iio_disable_buffers(indio_dev);
+ if (ret)
+ goto err_deactivate_all;
+
+ if (remove_buffer)
+ iio_buffer_deactivate(remove_buffer);
+ if (insert_buffer)
+ iio_buffer_activate(indio_dev, insert_buffer);
+
+ /* If no buffers in list, we are done */
+ if (list_empty(&iio_dev_opaque->buffer_list))
+ return 0;
+
+ ret = iio_enable_buffers(indio_dev, &new_config);
+ if (ret)
+ goto err_deactivate_all;
+
+ return 0;
+
+err_deactivate_all:
+ /*
+ * We've already verified that the config is valid earlier. If things go
+ * wrong in either enable or disable the most likely reason is an IO
+ * error from the device. In this case there is no good recovery
+ * strategy. Just make sure to disable everything and leave the device
+ * in a sane state. With a bit of luck the device might come back to
+ * life again later and userspace can try again.
+ */
+ iio_buffer_deactivate_all(indio_dev);
+
+err_free_config:
+ iio_free_scan_mask(indio_dev, new_config.scan_mask);
+ return ret;
+}
+
+int iio_update_buffers(struct iio_dev *indio_dev,
+ struct iio_buffer *insert_buffer,
+ struct iio_buffer *remove_buffer)
+{
+ struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
+ int ret;
+
+ if (insert_buffer == remove_buffer)
+ return 0;
+
+ if (insert_buffer &&
+ insert_buffer->direction == IIO_BUFFER_DIRECTION_OUT)
+ return -EINVAL;
+
+ mutex_lock(&iio_dev_opaque->info_exist_lock);
+ mutex_lock(&iio_dev_opaque->mlock);
+
+ if (insert_buffer && iio_buffer_is_active(insert_buffer))
+ insert_buffer = NULL;
+
+ if (remove_buffer && !iio_buffer_is_active(remove_buffer))
+ remove_buffer = NULL;
+
+ if (!insert_buffer && !remove_buffer) {
+ ret = 0;
+ goto out_unlock;
+ }
+
+ if (!indio_dev->info) {
+ ret = -ENODEV;
+ goto out_unlock;
+ }
+
+ ret = __iio_update_buffers(indio_dev, insert_buffer, remove_buffer);
+
+out_unlock:
+ mutex_unlock(&iio_dev_opaque->mlock);
+ mutex_unlock(&iio_dev_opaque->info_exist_lock);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(iio_update_buffers);
+
+void iio_disable_all_buffers(struct iio_dev *indio_dev)
+{
+ iio_disable_buffers(indio_dev);
+ iio_buffer_deactivate_all(indio_dev);
+}
+
+static ssize_t enable_store(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t len)
+{
+ int ret;
+ bool requested_state;
+ struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+ struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
+ struct iio_buffer *buffer = to_iio_dev_attr(attr)->buffer;
+ bool inlist;
+
+ ret = kstrtobool(buf, &requested_state);
+ if (ret < 0)
+ return ret;
+
+ mutex_lock(&iio_dev_opaque->mlock);
+
+ /* Find out if it is in the list */
+ inlist = iio_buffer_is_active(buffer);
+ /* Already in desired state */
+ if (inlist == requested_state)
+ goto done;
+
+ if (requested_state)
+ ret = __iio_update_buffers(indio_dev, buffer, NULL);
+ else
+ ret = __iio_update_buffers(indio_dev, NULL, buffer);
+
+done:
+ mutex_unlock(&iio_dev_opaque->mlock);
+ return (ret < 0) ? ret : len;
+}
+
+static ssize_t watermark_show(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ struct iio_buffer *buffer = to_iio_dev_attr(attr)->buffer;
+
+ return sysfs_emit(buf, "%u\n", buffer->watermark);
+}
+
+static ssize_t watermark_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t len)
+{
+ struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+ struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
+ struct iio_buffer *buffer = to_iio_dev_attr(attr)->buffer;
+ unsigned int val;
+ int ret;
+
+ ret = kstrtouint(buf, 10, &val);
+ if (ret)
+ return ret;
+ if (!val)
+ return -EINVAL;
+
+ mutex_lock(&iio_dev_opaque->mlock);
+
+ if (val > buffer->length) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ if (iio_buffer_is_active(buffer)) {
+ ret = -EBUSY;
+ goto out;
+ }
+
+ buffer->watermark = val;
+out:
+ mutex_unlock(&iio_dev_opaque->mlock);
+
+ return ret ? ret : len;
+}
+
+static ssize_t data_available_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct iio_buffer *buffer = to_iio_dev_attr(attr)->buffer;
+
+ return sysfs_emit(buf, "%zu\n", iio_buffer_data_available(buffer));
+}
+
+static ssize_t direction_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct iio_buffer *buffer = to_iio_dev_attr(attr)->buffer;
+
+ switch (buffer->direction) {
+ case IIO_BUFFER_DIRECTION_IN:
+ return sysfs_emit(buf, "in\n");
+ case IIO_BUFFER_DIRECTION_OUT:
+ return sysfs_emit(buf, "out\n");
+ default:
+ return -EINVAL;
+ }
+}
+
+static DEVICE_ATTR_RW(length);
+static struct device_attribute dev_attr_length_ro = __ATTR_RO(length);
+static DEVICE_ATTR_RW(enable);
+static DEVICE_ATTR_RW(watermark);
+static struct device_attribute dev_attr_watermark_ro = __ATTR_RO(watermark);
+static DEVICE_ATTR_RO(data_available);
+static DEVICE_ATTR_RO(direction);
+
+/*
+ * When adding new attributes here, put the at the end, at least until
+ * the code that handles the length/length_ro & watermark/watermark_ro
+ * assignments gets cleaned up. Otherwise these can create some weird
+ * duplicate attributes errors under some setups.
+ */
+static struct attribute *iio_buffer_attrs[] = {
+ &dev_attr_length.attr,
+ &dev_attr_enable.attr,
+ &dev_attr_watermark.attr,
+ &dev_attr_data_available.attr,
+ &dev_attr_direction.attr,
+};
+
+#define to_dev_attr(_attr) container_of(_attr, struct device_attribute, attr)
+
+static struct attribute *iio_buffer_wrap_attr(struct iio_buffer *buffer,
+ struct attribute *attr)
+{
+ struct device_attribute *dattr = to_dev_attr(attr);
+ struct iio_dev_attr *iio_attr;
+
+ iio_attr = kzalloc(sizeof(*iio_attr), GFP_KERNEL);
+ if (!iio_attr)
+ return NULL;
+
+ iio_attr->buffer = buffer;
+ memcpy(&iio_attr->dev_attr, dattr, sizeof(iio_attr->dev_attr));
+ iio_attr->dev_attr.attr.name = kstrdup_const(attr->name, GFP_KERNEL);
+ if (!iio_attr->dev_attr.attr.name) {
+ kfree(iio_attr);
+ return NULL;
+ }
+
+ sysfs_attr_init(&iio_attr->dev_attr.attr);
+
+ list_add(&iio_attr->l, &buffer->buffer_attr_list);
+
+ return &iio_attr->dev_attr.attr;
+}
+
+static int iio_buffer_register_legacy_sysfs_groups(struct iio_dev *indio_dev,
+ struct attribute **buffer_attrs,
+ int buffer_attrcount,
+ int scan_el_attrcount)
+{
+ struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
+ struct attribute_group *group;
+ struct attribute **attrs;
+ int ret;
+
+ attrs = kcalloc(buffer_attrcount + 1, sizeof(*attrs), GFP_KERNEL);
+ if (!attrs)
+ return -ENOMEM;
+
+ memcpy(attrs, buffer_attrs, buffer_attrcount * sizeof(*attrs));
+
+ group = &iio_dev_opaque->legacy_buffer_group;
+ group->attrs = attrs;
+ group->name = "buffer";
+
+ ret = iio_device_register_sysfs_group(indio_dev, group);
+ if (ret)
+ goto error_free_buffer_attrs;
+
+ attrs = kcalloc(scan_el_attrcount + 1, sizeof(*attrs), GFP_KERNEL);
+ if (!attrs) {
+ ret = -ENOMEM;
+ goto error_free_buffer_attrs;
+ }
+
+ memcpy(attrs, &buffer_attrs[buffer_attrcount],
+ scan_el_attrcount * sizeof(*attrs));
+
+ group = &iio_dev_opaque->legacy_scan_el_group;
+ group->attrs = attrs;
+ group->name = "scan_elements";
+
+ ret = iio_device_register_sysfs_group(indio_dev, group);
+ if (ret)
+ goto error_free_scan_el_attrs;
+
+ return 0;
+
+error_free_scan_el_attrs:
+ kfree(iio_dev_opaque->legacy_scan_el_group.attrs);
+error_free_buffer_attrs:
+ kfree(iio_dev_opaque->legacy_buffer_group.attrs);
+
+ return ret;
+}
+
+static void iio_buffer_unregister_legacy_sysfs_groups(struct iio_dev *indio_dev)
+{
+ struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
+
+ kfree(iio_dev_opaque->legacy_buffer_group.attrs);
+ kfree(iio_dev_opaque->legacy_scan_el_group.attrs);
+}
+
+static int iio_buffer_chrdev_release(struct inode *inode, struct file *filep)
+{
+ struct iio_dev_buffer_pair *ib = filep->private_data;
+ struct iio_dev *indio_dev = ib->indio_dev;
+ struct iio_buffer *buffer = ib->buffer;
+
+ wake_up(&buffer->pollq);
+
+ kfree(ib);
+ clear_bit(IIO_BUSY_BIT_POS, &buffer->flags);
+ iio_device_put(indio_dev);
+
+ return 0;
+}
+
+static const struct file_operations iio_buffer_chrdev_fileops = {
+ .owner = THIS_MODULE,
+ .llseek = noop_llseek,
+ .read = iio_buffer_read,
+ .write = iio_buffer_write,
+ .poll = iio_buffer_poll,
+ .release = iio_buffer_chrdev_release,
+};
+
+static long iio_device_buffer_getfd(struct iio_dev *indio_dev, unsigned long arg)
+{
+ struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
+ int __user *ival = (int __user *)arg;
+ struct iio_dev_buffer_pair *ib;
+ struct iio_buffer *buffer;
+ int fd, idx, ret;
+
+ if (copy_from_user(&idx, ival, sizeof(idx)))
+ return -EFAULT;
+
+ if (idx >= iio_dev_opaque->attached_buffers_cnt)
+ return -ENODEV;
+
+ iio_device_get(indio_dev);
+
+ buffer = iio_dev_opaque->attached_buffers[idx];
+
+ if (test_and_set_bit(IIO_BUSY_BIT_POS, &buffer->flags)) {
+ ret = -EBUSY;
+ goto error_iio_dev_put;
+ }
+
+ ib = kzalloc(sizeof(*ib), GFP_KERNEL);
+ if (!ib) {
+ ret = -ENOMEM;
+ goto error_clear_busy_bit;
+ }
+
+ ib->indio_dev = indio_dev;
+ ib->buffer = buffer;
+
+ fd = anon_inode_getfd("iio:buffer", &iio_buffer_chrdev_fileops,
+ ib, O_RDWR | O_CLOEXEC);
+ if (fd < 0) {
+ ret = fd;
+ goto error_free_ib;
+ }
+
+ if (copy_to_user(ival, &fd, sizeof(fd))) {
+ /*
+ * "Leak" the fd, as there's not much we can do about this
+ * anyway. 'fd' might have been closed already, as
+ * anon_inode_getfd() called fd_install() on it, which made
+ * it reachable by userland.
+ *
+ * Instead of allowing a malicious user to play tricks with
+ * us, rely on the process exit path to do any necessary
+ * cleanup, as in releasing the file, if still needed.
+ */
+ return -EFAULT;
+ }
+
+ return 0;
+
+error_free_ib:
+ kfree(ib);
+error_clear_busy_bit:
+ clear_bit(IIO_BUSY_BIT_POS, &buffer->flags);
+error_iio_dev_put:
+ iio_device_put(indio_dev);
+ return ret;
+}
+
+static long iio_device_buffer_ioctl(struct iio_dev *indio_dev, struct file *filp,
+ unsigned int cmd, unsigned long arg)
+{
+ switch (cmd) {
+ case IIO_BUFFER_GET_FD_IOCTL:
+ return iio_device_buffer_getfd(indio_dev, arg);
+ default:
+ return IIO_IOCTL_UNHANDLED;
+ }
+}
+
+static int __iio_buffer_alloc_sysfs_and_mask(struct iio_buffer *buffer,
+ struct iio_dev *indio_dev,
+ int index)
+{
+ struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
+ struct iio_dev_attr *p;
+ const struct iio_dev_attr *id_attr;
+ struct attribute **attr;
+ int ret, i, attrn, scan_el_attrcount, buffer_attrcount;
+ const struct iio_chan_spec *channels;
+
+ buffer_attrcount = 0;
+ if (buffer->attrs) {
+ while (buffer->attrs[buffer_attrcount])
+ buffer_attrcount++;
+ }
+ buffer_attrcount += ARRAY_SIZE(iio_buffer_attrs);
+
+ scan_el_attrcount = 0;
+ INIT_LIST_HEAD(&buffer->buffer_attr_list);
+ channels = indio_dev->channels;
+ if (channels) {
+ /* new magic */
+ for (i = 0; i < indio_dev->num_channels; i++) {
+ if (channels[i].scan_index < 0)
+ continue;
+
+ /* Verify that sample bits fit into storage */
+ if (channels[i].scan_type.storagebits <
+ channels[i].scan_type.realbits +
+ channels[i].scan_type.shift) {
+ dev_err(&indio_dev->dev,
+ "Channel %d storagebits (%d) < shifted realbits (%d + %d)\n",
+ i, channels[i].scan_type.storagebits,
+ channels[i].scan_type.realbits,
+ channels[i].scan_type.shift);
+ ret = -EINVAL;
+ goto error_cleanup_dynamic;
+ }
+
+ ret = iio_buffer_add_channel_sysfs(indio_dev, buffer,
+ &channels[i]);
+ if (ret < 0)
+ goto error_cleanup_dynamic;
+ scan_el_attrcount += ret;
+ if (channels[i].type == IIO_TIMESTAMP)
+ iio_dev_opaque->scan_index_timestamp =
+ channels[i].scan_index;
+ }
+ if (indio_dev->masklength && !buffer->scan_mask) {
+ buffer->scan_mask = bitmap_zalloc(indio_dev->masklength,
+ GFP_KERNEL);
+ if (!buffer->scan_mask) {
+ ret = -ENOMEM;
+ goto error_cleanup_dynamic;
+ }
+ }
+ }
+
+ attrn = buffer_attrcount + scan_el_attrcount;
+ attr = kcalloc(attrn + 1, sizeof(*attr), GFP_KERNEL);
+ if (!attr) {
+ ret = -ENOMEM;
+ goto error_free_scan_mask;
+ }
+
+ memcpy(attr, iio_buffer_attrs, sizeof(iio_buffer_attrs));
+ if (!buffer->access->set_length)
+ attr[0] = &dev_attr_length_ro.attr;
+
+ if (buffer->access->flags & INDIO_BUFFER_FLAG_FIXED_WATERMARK)
+ attr[2] = &dev_attr_watermark_ro.attr;
+
+ if (buffer->attrs)
+ for (i = 0, id_attr = buffer->attrs[i];
+ (id_attr = buffer->attrs[i]); i++)
+ attr[ARRAY_SIZE(iio_buffer_attrs) + i] =
+ (struct attribute *)&id_attr->dev_attr.attr;
+
+ buffer->buffer_group.attrs = attr;
+
+ for (i = 0; i < buffer_attrcount; i++) {
+ struct attribute *wrapped;
+
+ wrapped = iio_buffer_wrap_attr(buffer, attr[i]);
+ if (!wrapped) {
+ ret = -ENOMEM;
+ goto error_free_buffer_attrs;
+ }
+ attr[i] = wrapped;
+ }
+
+ attrn = 0;
+ list_for_each_entry(p, &buffer->buffer_attr_list, l)
+ attr[attrn++] = &p->dev_attr.attr;
+
+ buffer->buffer_group.name = kasprintf(GFP_KERNEL, "buffer%d", index);
+ if (!buffer->buffer_group.name) {
+ ret = -ENOMEM;
+ goto error_free_buffer_attrs;
+ }
+
+ ret = iio_device_register_sysfs_group(indio_dev, &buffer->buffer_group);
+ if (ret)
+ goto error_free_buffer_attr_group_name;
+
+ /* we only need to register the legacy groups for the first buffer */
+ if (index > 0)
+ return 0;
+
+ ret = iio_buffer_register_legacy_sysfs_groups(indio_dev, attr,
+ buffer_attrcount,
+ scan_el_attrcount);
+ if (ret)
+ goto error_free_buffer_attr_group_name;
+
+ return 0;
+
+error_free_buffer_attr_group_name:
+ kfree(buffer->buffer_group.name);
+error_free_buffer_attrs:
+ kfree(buffer->buffer_group.attrs);
+error_free_scan_mask:
+ bitmap_free(buffer->scan_mask);
+error_cleanup_dynamic:
+ iio_free_chan_devattr_list(&buffer->buffer_attr_list);
+
+ return ret;
+}
+
+static void __iio_buffer_free_sysfs_and_mask(struct iio_buffer *buffer,
+ struct iio_dev *indio_dev,
+ int index)
+{
+ if (index == 0)
+ iio_buffer_unregister_legacy_sysfs_groups(indio_dev);
+ bitmap_free(buffer->scan_mask);
+ kfree(buffer->buffer_group.name);
+ kfree(buffer->buffer_group.attrs);
+ iio_free_chan_devattr_list(&buffer->buffer_attr_list);
+}
+
+int iio_buffers_alloc_sysfs_and_mask(struct iio_dev *indio_dev)
+{
+ struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
+ const struct iio_chan_spec *channels;
+ struct iio_buffer *buffer;
+ int ret, i, idx;
+ size_t sz;
+
+ channels = indio_dev->channels;
+ if (channels) {
+ int ml = indio_dev->masklength;
+
+ for (i = 0; i < indio_dev->num_channels; i++)
+ ml = max(ml, channels[i].scan_index + 1);
+ indio_dev->masklength = ml;
+ }
+
+ if (!iio_dev_opaque->attached_buffers_cnt)
+ return 0;
+
+ for (idx = 0; idx < iio_dev_opaque->attached_buffers_cnt; idx++) {
+ buffer = iio_dev_opaque->attached_buffers[idx];
+ ret = __iio_buffer_alloc_sysfs_and_mask(buffer, indio_dev, idx);
+ if (ret)
+ goto error_unwind_sysfs_and_mask;
+ }
+
+ sz = sizeof(*iio_dev_opaque->buffer_ioctl_handler);
+ iio_dev_opaque->buffer_ioctl_handler = kzalloc(sz, GFP_KERNEL);
+ if (!iio_dev_opaque->buffer_ioctl_handler) {
+ ret = -ENOMEM;
+ goto error_unwind_sysfs_and_mask;
+ }
+
+ iio_dev_opaque->buffer_ioctl_handler->ioctl = iio_device_buffer_ioctl;
+ iio_device_ioctl_handler_register(indio_dev,
+ iio_dev_opaque->buffer_ioctl_handler);
+
+ return 0;
+
+error_unwind_sysfs_and_mask:
+ while (idx--) {
+ buffer = iio_dev_opaque->attached_buffers[idx];
+ __iio_buffer_free_sysfs_and_mask(buffer, indio_dev, idx);
+ }
+ return ret;
+}
+
+void iio_buffers_free_sysfs_and_mask(struct iio_dev *indio_dev)
+{
+ struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
+ struct iio_buffer *buffer;
+ int i;
+
+ if (!iio_dev_opaque->attached_buffers_cnt)
+ return;
+
+ iio_device_ioctl_handler_unregister(iio_dev_opaque->buffer_ioctl_handler);
+ kfree(iio_dev_opaque->buffer_ioctl_handler);
+
+ for (i = iio_dev_opaque->attached_buffers_cnt - 1; i >= 0; i--) {
+ buffer = iio_dev_opaque->attached_buffers[i];
+ __iio_buffer_free_sysfs_and_mask(buffer, indio_dev, i);
+ }
+}
+
+/**
+ * iio_validate_scan_mask_onehot() - Validates that exactly one channel is selected
+ * @indio_dev: the iio device
+ * @mask: scan mask to be checked
+ *
+ * Return true if exactly one bit is set in the scan mask, false otherwise. It
+ * can be used for devices where only one channel can be active for sampling at
+ * a time.
+ */
+bool iio_validate_scan_mask_onehot(struct iio_dev *indio_dev,
+ const unsigned long *mask)
+{
+ return bitmap_weight(mask, indio_dev->masklength) == 1;
+}
+EXPORT_SYMBOL_GPL(iio_validate_scan_mask_onehot);
+
+static const void *iio_demux(struct iio_buffer *buffer,
+ const void *datain)
+{
+ struct iio_demux_table *t;
+
+ if (list_empty(&buffer->demux_list))
+ return datain;
+ list_for_each_entry(t, &buffer->demux_list, l)
+ memcpy(buffer->demux_bounce + t->to,
+ datain + t->from, t->length);
+
+ return buffer->demux_bounce;
+}
+
+static int iio_push_to_buffer(struct iio_buffer *buffer, const void *data)
+{
+ const void *dataout = iio_demux(buffer, data);
+ int ret;
+
+ ret = buffer->access->store_to(buffer, dataout);
+ if (ret)
+ return ret;
+
+ /*
+ * We can't just test for watermark to decide if we wake the poll queue
+ * because read may request less samples than the watermark.
+ */
+ wake_up_interruptible_poll(&buffer->pollq, EPOLLIN | EPOLLRDNORM);
+ return 0;
+}
+
+/**
+ * iio_push_to_buffers() - push to a registered buffer.
+ * @indio_dev: iio_dev structure for device.
+ * @data: Full scan.
+ */
+int iio_push_to_buffers(struct iio_dev *indio_dev, const void *data)
+{
+ struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
+ int ret;
+ struct iio_buffer *buf;
+
+ list_for_each_entry(buf, &iio_dev_opaque->buffer_list, buffer_list) {
+ ret = iio_push_to_buffer(buf, data);
+ if (ret < 0)
+ return ret;
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(iio_push_to_buffers);
+
+/**
+ * iio_push_to_buffers_with_ts_unaligned() - push to registered buffer,
+ * no alignment or space requirements.
+ * @indio_dev: iio_dev structure for device.
+ * @data: channel data excluding the timestamp.
+ * @data_sz: size of data.
+ * @timestamp: timestamp for the sample data.
+ *
+ * This special variant of iio_push_to_buffers_with_timestamp() does
+ * not require space for the timestamp, or 8 byte alignment of data.
+ * It does however require an allocation on first call and additional
+ * copies on all calls, so should be avoided if possible.
+ */
+int iio_push_to_buffers_with_ts_unaligned(struct iio_dev *indio_dev,
+ const void *data,
+ size_t data_sz,
+ int64_t timestamp)
+{
+ struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
+
+ /*
+ * Conservative estimate - we can always safely copy the minimum
+ * of either the data provided or the length of the destination buffer.
+ * This relaxed limit allows the calling drivers to be lax about
+ * tracking the size of the data they are pushing, at the cost of
+ * unnecessary copying of padding.
+ */
+ data_sz = min_t(size_t, indio_dev->scan_bytes, data_sz);
+ if (iio_dev_opaque->bounce_buffer_size != indio_dev->scan_bytes) {
+ void *bb;
+
+ bb = devm_krealloc(&indio_dev->dev,
+ iio_dev_opaque->bounce_buffer,
+ indio_dev->scan_bytes, GFP_KERNEL);
+ if (!bb)
+ return -ENOMEM;
+ iio_dev_opaque->bounce_buffer = bb;
+ iio_dev_opaque->bounce_buffer_size = indio_dev->scan_bytes;
+ }
+ memcpy(iio_dev_opaque->bounce_buffer, data, data_sz);
+ return iio_push_to_buffers_with_timestamp(indio_dev,
+ iio_dev_opaque->bounce_buffer,
+ timestamp);
+}
+EXPORT_SYMBOL_GPL(iio_push_to_buffers_with_ts_unaligned);
+
+/**
+ * iio_buffer_release() - Free a buffer's resources
+ * @ref: Pointer to the kref embedded in the iio_buffer struct
+ *
+ * This function is called when the last reference to the buffer has been
+ * dropped. It will typically free all resources allocated by the buffer. Do not
+ * call this function manually, always use iio_buffer_put() when done using a
+ * buffer.
+ */
+static void iio_buffer_release(struct kref *ref)
+{
+ struct iio_buffer *buffer = container_of(ref, struct iio_buffer, ref);
+
+ buffer->access->release(buffer);
+}
+
+/**
+ * iio_buffer_get() - Grab a reference to the buffer
+ * @buffer: The buffer to grab a reference for, may be NULL
+ *
+ * Returns the pointer to the buffer that was passed into the function.
+ */
+struct iio_buffer *iio_buffer_get(struct iio_buffer *buffer)
+{
+ if (buffer)
+ kref_get(&buffer->ref);
+
+ return buffer;
+}
+EXPORT_SYMBOL_GPL(iio_buffer_get);
+
+/**
+ * iio_buffer_put() - Release the reference to the buffer
+ * @buffer: The buffer to release the reference for, may be NULL
+ */
+void iio_buffer_put(struct iio_buffer *buffer)
+{
+ if (buffer)
+ kref_put(&buffer->ref, iio_buffer_release);
+}
+EXPORT_SYMBOL_GPL(iio_buffer_put);
+
+/**
+ * iio_device_attach_buffer - Attach a buffer to a IIO device
+ * @indio_dev: The device the buffer should be attached to
+ * @buffer: The buffer to attach to the device
+ *
+ * Return 0 if successful, negative if error.
+ *
+ * This function attaches a buffer to a IIO device. The buffer stays attached to
+ * the device until the device is freed. For legacy reasons, the first attached
+ * buffer will also be assigned to 'indio_dev->buffer'.
+ * The array allocated here, will be free'd via the iio_device_detach_buffers()
+ * call which is handled by the iio_device_free().
+ */
+int iio_device_attach_buffer(struct iio_dev *indio_dev,
+ struct iio_buffer *buffer)
+{
+ struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
+ struct iio_buffer **new, **old = iio_dev_opaque->attached_buffers;
+ unsigned int cnt = iio_dev_opaque->attached_buffers_cnt;
+
+ cnt++;
+
+ new = krealloc(old, sizeof(*new) * cnt, GFP_KERNEL);
+ if (!new)
+ return -ENOMEM;
+ iio_dev_opaque->attached_buffers = new;
+
+ buffer = iio_buffer_get(buffer);
+
+ /* first buffer is legacy; attach it to the IIO device directly */
+ if (!indio_dev->buffer)
+ indio_dev->buffer = buffer;
+
+ iio_dev_opaque->attached_buffers[cnt - 1] = buffer;
+ iio_dev_opaque->attached_buffers_cnt = cnt;
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(iio_device_attach_buffer);