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path: root/drivers/iio/industrialio-buffer.c
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-rw-r--r--drivers/iio/industrialio-buffer.c1262
1 files changed, 1262 insertions, 0 deletions
diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio-buffer.c
new file mode 100644
index 000000000..df919f44d
--- /dev/null
+++ b/drivers/iio/industrialio-buffer.c
@@ -0,0 +1,1262 @@
+/* The industrial I/O core
+ *
+ * Copyright (c) 2008 Jonathan Cameron
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ *
+ * Handling of buffer allocation / resizing.
+ *
+ *
+ * Things to look at here.
+ * - Better memory allocation techniques?
+ * - Alternative access techniques?
+ */
+#include <linux/kernel.h>
+#include <linux/export.h>
+#include <linux/device.h>
+#include <linux/fs.h>
+#include <linux/cdev.h>
+#include <linux/slab.h>
+#include <linux/poll.h>
+#include <linux/sched.h>
+
+#include <linux/iio/iio.h>
+#include "iio_core.h"
+#include <linux/iio/sysfs.h>
+#include <linux/iio/buffer.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);
+ 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_first_n_outer() - chrdev read for buffer access
+ *
+ * This function relies on all buffer implementations having an
+ * iio_buffer as their first element.
+ **/
+ssize_t iio_buffer_read_first_n_outer(struct file *filp, char __user *buf,
+ size_t n, loff_t *f_ps)
+{
+ struct iio_dev *indio_dev = filp->private_data;
+ struct iio_buffer *rb = indio_dev->buffer;
+ size_t datum_size;
+ size_t to_wait = 0;
+ size_t to_read;
+ int ret;
+
+ if (!indio_dev->info)
+ return -ENODEV;
+
+ if (!rb || !rb->access->read_first_n)
+ return -EINVAL;
+
+ 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;
+
+ to_read = min_t(size_t, n / datum_size, rb->watermark);
+
+ if (!(filp->f_flags & O_NONBLOCK))
+ to_wait = to_read;
+
+ do {
+ ret = wait_event_interruptible(rb->pollq,
+ iio_buffer_ready(indio_dev, rb, to_wait, to_read));
+ if (ret)
+ return ret;
+
+ if (!indio_dev->info)
+ return -ENODEV;
+
+ ret = rb->access->read_first_n(rb, n, buf);
+ if (ret == 0 && (filp->f_flags & O_NONBLOCK))
+ ret = -EAGAIN;
+ } while (ret == 0);
+
+ return ret;
+}
+
+/**
+ * iio_buffer_poll() - poll the buffer to find out if it has data
+ */
+unsigned int iio_buffer_poll(struct file *filp,
+ struct poll_table_struct *wait)
+{
+ struct iio_dev *indio_dev = filp->private_data;
+ struct iio_buffer *rb = indio_dev->buffer;
+
+ if (!indio_dev->info)
+ return -ENODEV;
+
+ poll_wait(filp, &rb->pollq, wait);
+ if (iio_buffer_ready(indio_dev, rb, rb->watermark, 0))
+ return POLLIN | POLLRDNORM;
+ return 0;
+}
+
+/**
+ * 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)
+{
+ if (!indio_dev->buffer)
+ return;
+
+ wake_up(&indio_dev->buffer->pollq);
+}
+
+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);
+ buffer->watermark = 1;
+}
+EXPORT_SYMBOL(iio_buffer_init);
+
+static ssize_t iio_show_scan_index(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ return sprintf(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 sprintf(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 sprintf(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_dev *indio_dev = dev_to_iio_dev(dev);
+
+ /* Ensure ret is 0 or 1. */
+ ret = !!test_bit(to_iio_dev_attr(attr)->address,
+ indio_dev->buffer->scan_mask);
+
+ return sprintf(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)
+{
+ if (bitmap_empty(mask, masklength))
+ return NULL;
+ while (*av_masks) {
+ 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;
+
+ trialmask = kmalloc(sizeof(*trialmask)*
+ BITS_TO_LONGS(indio_dev->masklength),
+ GFP_KERNEL);
+
+ if (trialmask == NULL)
+ return -ENOMEM;
+ if (!indio_dev->masklength) {
+ WARN_ON("Trying to set scanmask prior to registering buffer\n");
+ goto err_invalid_mask;
+ }
+ 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);
+ if (!mask)
+ goto err_invalid_mask;
+ }
+ bitmap_copy(buffer->scan_mask, trialmask, indio_dev->masklength);
+
+ kfree(trialmask);
+
+ return 0;
+
+err_invalid_mask:
+ kfree(trialmask);
+ return -EINVAL;
+}
+
+static int iio_scan_mask_clear(struct iio_buffer *buffer, int bit)
+{
+ clear_bit(bit, buffer->scan_mask);
+ return 0;
+}
+
+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_buffer *buffer = indio_dev->buffer;
+ struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
+
+ ret = strtobool(buf, &state);
+ if (ret < 0)
+ return ret;
+ mutex_lock(&indio_dev->mlock);
+ if (iio_buffer_is_active(indio_dev->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(&indio_dev->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_dev *indio_dev = dev_to_iio_dev(dev);
+ return sprintf(buf, "%d\n", indio_dev->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);
+ bool state;
+
+ ret = strtobool(buf, &state);
+ if (ret < 0)
+ return ret;
+
+ mutex_lock(&indio_dev->mlock);
+ if (iio_buffer_is_active(indio_dev->buffer)) {
+ ret = -EBUSY;
+ goto error_ret;
+ }
+ indio_dev->buffer->scan_timestamp = state;
+error_ret:
+ mutex_unlock(&indio_dev->mlock);
+
+ return ret ? ret : len;
+}
+
+static int iio_buffer_add_channel_sysfs(struct iio_dev *indio_dev,
+ const struct iio_chan_spec *chan)
+{
+ int ret, attrcount = 0;
+ struct iio_buffer *buffer = indio_dev->buffer;
+
+ ret = __iio_add_chan_devattr("index",
+ chan,
+ &iio_show_scan_index,
+ NULL,
+ 0,
+ IIO_SEPARATE,
+ &indio_dev->dev,
+ &buffer->scan_el_dev_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->scan_el_dev_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->scan_el_dev_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->scan_el_dev_attr_list);
+ if (ret)
+ return ret;
+ attrcount++;
+ ret = attrcount;
+ return ret;
+}
+
+static ssize_t iio_buffer_read_length(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+ struct iio_buffer *buffer = indio_dev->buffer;
+
+ return sprintf(buf, "%d\n", buffer->length);
+}
+
+static ssize_t iio_buffer_write_length(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_buffer *buffer = indio_dev->buffer;
+ unsigned int val;
+ int ret;
+
+ ret = kstrtouint(buf, 10, &val);
+ if (ret)
+ return ret;
+
+ if (val == buffer->length)
+ return len;
+
+ mutex_lock(&indio_dev->mlock);
+ if (iio_buffer_is_active(indio_dev->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(&indio_dev->mlock);
+
+ return ret ? ret : len;
+}
+
+static ssize_t iio_buffer_show_enable(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+ return sprintf(buf, "%d\n", iio_buffer_is_active(indio_dev->buffer));
+}
+
+static int iio_compute_scan_bytes(struct iio_dev *indio_dev,
+ const unsigned long *mask, bool timestamp)
+{
+ const struct iio_chan_spec *ch;
+ unsigned bytes = 0;
+ int length, i;
+
+ /* How much space will the demuxed element take? */
+ for_each_set_bit(i, mask,
+ indio_dev->masklength) {
+ ch = iio_find_channel_from_si(indio_dev, i);
+ if (ch->scan_type.repeat > 1)
+ length = ch->scan_type.storagebits / 8 *
+ ch->scan_type.repeat;
+ else
+ length = ch->scan_type.storagebits / 8;
+ bytes = ALIGN(bytes, length);
+ bytes += length;
+ }
+ if (timestamp) {
+ ch = iio_find_channel_from_si(indio_dev,
+ indio_dev->scan_index_timestamp);
+ if (ch->scan_type.repeat > 1)
+ length = ch->scan_type.storagebits / 8 *
+ ch->scan_type.repeat;
+ else
+ length = ch->scan_type.storagebits / 8;
+ bytes = ALIGN(bytes, length);
+ bytes += length;
+ }
+ return bytes;
+}
+
+static void iio_buffer_activate(struct iio_dev *indio_dev,
+ struct iio_buffer *buffer)
+{
+ iio_buffer_get(buffer);
+ list_add(&buffer->buffer_list, &indio_dev->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);
+}
+
+void iio_disable_all_buffers(struct iio_dev *indio_dev)
+{
+ struct iio_buffer *buffer, *_buffer;
+
+ if (list_empty(&indio_dev->buffer_list))
+ return;
+
+ if (indio_dev->setup_ops->predisable)
+ indio_dev->setup_ops->predisable(indio_dev);
+
+ list_for_each_entry_safe(buffer, _buffer,
+ &indio_dev->buffer_list, buffer_list)
+ iio_buffer_deactivate(buffer);
+
+ indio_dev->currentmode = INDIO_DIRECT_MODE;
+ if (indio_dev->setup_ops->postdisable)
+ indio_dev->setup_ops->postdisable(indio_dev);
+
+ if (indio_dev->available_scan_masks == NULL)
+ kfree(indio_dev->active_scan_mask);
+}
+
+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_update_buffers(struct iio_dev *indio_dev,
+ struct iio_buffer *insert_buffer,
+ struct iio_buffer *remove_buffer)
+{
+ int ret;
+ int success = 0;
+ struct iio_buffer *buffer;
+ unsigned long *compound_mask;
+ const unsigned long *old_mask;
+
+ /* Wind down existing buffers - iff there are any */
+ if (!list_empty(&indio_dev->buffer_list)) {
+ if (indio_dev->setup_ops->predisable) {
+ ret = indio_dev->setup_ops->predisable(indio_dev);
+ if (ret)
+ return ret;
+ }
+ indio_dev->currentmode = INDIO_DIRECT_MODE;
+ if (indio_dev->setup_ops->postdisable) {
+ ret = indio_dev->setup_ops->postdisable(indio_dev);
+ if (ret)
+ return ret;
+ }
+ }
+ /* Keep a copy of current setup to allow roll back */
+ old_mask = indio_dev->active_scan_mask;
+ if (!indio_dev->available_scan_masks)
+ indio_dev->active_scan_mask = NULL;
+
+ 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(&indio_dev->buffer_list)) {
+ indio_dev->currentmode = INDIO_DIRECT_MODE;
+ if (indio_dev->available_scan_masks == NULL)
+ kfree(old_mask);
+ return 0;
+ }
+
+ /* What scan mask do we actually have? */
+ compound_mask = kcalloc(BITS_TO_LONGS(indio_dev->masklength),
+ sizeof(long), GFP_KERNEL);
+ if (compound_mask == NULL) {
+ if (indio_dev->available_scan_masks == NULL)
+ kfree(old_mask);
+ return -ENOMEM;
+ }
+ indio_dev->scan_timestamp = 0;
+
+ list_for_each_entry(buffer, &indio_dev->buffer_list, buffer_list) {
+ bitmap_or(compound_mask, compound_mask, buffer->scan_mask,
+ indio_dev->masklength);
+ indio_dev->scan_timestamp |= buffer->scan_timestamp;
+ }
+ if (indio_dev->available_scan_masks) {
+ indio_dev->active_scan_mask =
+ iio_scan_mask_match(indio_dev->available_scan_masks,
+ indio_dev->masklength,
+ compound_mask);
+ if (indio_dev->active_scan_mask == NULL) {
+ /*
+ * Roll back.
+ * Note can only occur when adding a buffer.
+ */
+ iio_buffer_deactivate(insert_buffer);
+ if (old_mask) {
+ indio_dev->active_scan_mask = old_mask;
+ success = -EINVAL;
+ }
+ else {
+ kfree(compound_mask);
+ ret = -EINVAL;
+ return ret;
+ }
+ }
+ } else {
+ indio_dev->active_scan_mask = compound_mask;
+ }
+
+ iio_update_demux(indio_dev);
+
+ /* Wind up again */
+ if (indio_dev->setup_ops->preenable) {
+ ret = indio_dev->setup_ops->preenable(indio_dev);
+ if (ret) {
+ printk(KERN_ERR
+ "Buffer not started: buffer preenable failed (%d)\n", ret);
+ goto error_remove_inserted;
+ }
+ }
+ indio_dev->scan_bytes =
+ iio_compute_scan_bytes(indio_dev,
+ indio_dev->active_scan_mask,
+ indio_dev->scan_timestamp);
+ list_for_each_entry(buffer, &indio_dev->buffer_list, buffer_list) {
+ iio_buffer_update_bytes_per_datum(indio_dev, buffer);
+ if (buffer->access->request_update) {
+ ret = buffer->access->request_update(buffer);
+ if (ret) {
+ printk(KERN_INFO
+ "Buffer not started: buffer parameter update failed (%d)\n", ret);
+ goto error_run_postdisable;
+ }
+ }
+ }
+ if (indio_dev->info->update_scan_mode) {
+ ret = indio_dev->info
+ ->update_scan_mode(indio_dev,
+ indio_dev->active_scan_mask);
+ if (ret < 0) {
+ printk(KERN_INFO "Buffer not started: update scan mode failed (%d)\n", ret);
+ goto error_run_postdisable;
+ }
+ }
+ /* Definitely possible for devices to support both of these. */
+ if ((indio_dev->modes & INDIO_BUFFER_TRIGGERED) && indio_dev->trig) {
+ indio_dev->currentmode = INDIO_BUFFER_TRIGGERED;
+ } else if (indio_dev->modes & INDIO_BUFFER_HARDWARE) {
+ indio_dev->currentmode = INDIO_BUFFER_HARDWARE;
+ } else if (indio_dev->modes & INDIO_BUFFER_SOFTWARE) {
+ indio_dev->currentmode = INDIO_BUFFER_SOFTWARE;
+ } else { /* Should never be reached */
+ /* Can only occur on first buffer */
+ if (indio_dev->modes & INDIO_BUFFER_TRIGGERED)
+ pr_info("Buffer not started: no trigger\n");
+ ret = -EINVAL;
+ goto error_run_postdisable;
+ }
+
+ if (indio_dev->setup_ops->postenable) {
+ ret = indio_dev->setup_ops->postenable(indio_dev);
+ if (ret) {
+ printk(KERN_INFO
+ "Buffer not started: postenable failed (%d)\n", ret);
+ indio_dev->currentmode = INDIO_DIRECT_MODE;
+ if (indio_dev->setup_ops->postdisable)
+ indio_dev->setup_ops->postdisable(indio_dev);
+ goto error_disable_all_buffers;
+ }
+ }
+
+ if (indio_dev->available_scan_masks)
+ kfree(compound_mask);
+ else
+ kfree(old_mask);
+
+ return success;
+
+error_disable_all_buffers:
+ indio_dev->currentmode = INDIO_DIRECT_MODE;
+error_run_postdisable:
+ if (indio_dev->setup_ops->postdisable)
+ indio_dev->setup_ops->postdisable(indio_dev);
+error_remove_inserted:
+ if (insert_buffer)
+ iio_buffer_deactivate(insert_buffer);
+ indio_dev->active_scan_mask = old_mask;
+ kfree(compound_mask);
+ return ret;
+}
+
+int iio_update_buffers(struct iio_dev *indio_dev,
+ struct iio_buffer *insert_buffer,
+ struct iio_buffer *remove_buffer)
+{
+ int ret;
+
+ if (insert_buffer == remove_buffer)
+ return 0;
+
+ mutex_lock(&indio_dev->info_exist_lock);
+ mutex_lock(&indio_dev->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 == NULL) {
+ ret = -ENODEV;
+ goto out_unlock;
+ }
+
+ ret = __iio_update_buffers(indio_dev, insert_buffer, remove_buffer);
+
+out_unlock:
+ mutex_unlock(&indio_dev->mlock);
+ mutex_unlock(&indio_dev->info_exist_lock);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(iio_update_buffers);
+
+static ssize_t iio_buffer_store_enable(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);
+ bool inlist;
+
+ ret = strtobool(buf, &requested_state);
+ if (ret < 0)
+ return ret;
+
+ mutex_lock(&indio_dev->mlock);
+
+ /* Find out if it is in the list */
+ inlist = iio_buffer_is_active(indio_dev->buffer);
+ /* Already in desired state */
+ if (inlist == requested_state)
+ goto done;
+
+ if (requested_state)
+ ret = __iio_update_buffers(indio_dev,
+ indio_dev->buffer, NULL);
+ else
+ ret = __iio_update_buffers(indio_dev,
+ NULL, indio_dev->buffer);
+
+ if (ret < 0)
+ goto done;
+done:
+ mutex_unlock(&indio_dev->mlock);
+ return (ret < 0) ? ret : len;
+}
+
+static const char * const iio_scan_elements_group_name = "scan_elements";
+
+static ssize_t iio_buffer_show_watermark(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+ struct iio_buffer *buffer = indio_dev->buffer;
+
+ return sprintf(buf, "%u\n", buffer->watermark);
+}
+
+static ssize_t iio_buffer_store_watermark(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_buffer *buffer = indio_dev->buffer;
+ unsigned int val;
+ int ret;
+
+ ret = kstrtouint(buf, 10, &val);
+ if (ret)
+ return ret;
+ if (!val)
+ return -EINVAL;
+
+ mutex_lock(&indio_dev->mlock);
+
+ if (val > buffer->length) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ if (iio_buffer_is_active(indio_dev->buffer)) {
+ ret = -EBUSY;
+ goto out;
+ }
+
+ buffer->watermark = val;
+
+ if (indio_dev->info->hwfifo_set_watermark)
+ indio_dev->info->hwfifo_set_watermark(indio_dev, val);
+out:
+ mutex_unlock(&indio_dev->mlock);
+
+ return ret ? ret : len;
+}
+
+static DEVICE_ATTR(length, S_IRUGO | S_IWUSR, iio_buffer_read_length,
+ iio_buffer_write_length);
+static struct device_attribute dev_attr_length_ro = __ATTR(length,
+ S_IRUGO, iio_buffer_read_length, NULL);
+static DEVICE_ATTR(enable, S_IRUGO | S_IWUSR,
+ iio_buffer_show_enable, iio_buffer_store_enable);
+static DEVICE_ATTR(watermark, S_IRUGO | S_IWUSR,
+ iio_buffer_show_watermark, iio_buffer_store_watermark);
+
+static struct attribute *iio_buffer_attrs[] = {
+ &dev_attr_length.attr,
+ &dev_attr_enable.attr,
+ &dev_attr_watermark.attr,
+};
+
+int iio_buffer_alloc_sysfs_and_mask(struct iio_dev *indio_dev)
+{
+ struct iio_dev_attr *p;
+ struct attribute **attr;
+ struct iio_buffer *buffer = indio_dev->buffer;
+ int ret, i, attrn, attrcount, attrcount_orig = 0;
+ const struct iio_chan_spec *channels;
+
+ if (!buffer)
+ return 0;
+
+ attrcount = 0;
+ if (buffer->attrs) {
+ while (buffer->attrs[attrcount] != NULL)
+ attrcount++;
+ }
+
+ attr = kcalloc(attrcount + ARRAY_SIZE(iio_buffer_attrs) + 1,
+ sizeof(struct attribute *), GFP_KERNEL);
+ if (!attr)
+ return -ENOMEM;
+
+ memcpy(attr, iio_buffer_attrs, sizeof(iio_buffer_attrs));
+ if (!buffer->access->set_length)
+ attr[0] = &dev_attr_length_ro.attr;
+
+ if (buffer->attrs)
+ memcpy(&attr[ARRAY_SIZE(iio_buffer_attrs)], buffer->attrs,
+ sizeof(struct attribute *) * attrcount);
+
+ attr[attrcount + ARRAY_SIZE(iio_buffer_attrs)] = NULL;
+
+ buffer->buffer_group.name = "buffer";
+ buffer->buffer_group.attrs = attr;
+
+ indio_dev->groups[indio_dev->groupcounter++] = &buffer->buffer_group;
+
+ if (buffer->scan_el_attrs != NULL) {
+ attr = buffer->scan_el_attrs->attrs;
+ while (*attr++ != NULL)
+ attrcount_orig++;
+ }
+ attrcount = attrcount_orig;
+ INIT_LIST_HEAD(&buffer->scan_el_dev_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;
+
+ /* Establish necessary mask length */
+ if (channels[i].scan_index >
+ (int)indio_dev->masklength - 1)
+ indio_dev->masklength
+ = channels[i].scan_index + 1;
+
+ ret = iio_buffer_add_channel_sysfs(indio_dev,
+ &channels[i]);
+ if (ret < 0)
+ goto error_cleanup_dynamic;
+ attrcount += ret;
+ if (channels[i].type == IIO_TIMESTAMP)
+ indio_dev->scan_index_timestamp =
+ channels[i].scan_index;
+ }
+ if (indio_dev->masklength && buffer->scan_mask == NULL) {
+ buffer->scan_mask = kcalloc(BITS_TO_LONGS(indio_dev->masklength),
+ sizeof(*buffer->scan_mask),
+ GFP_KERNEL);
+ if (buffer->scan_mask == NULL) {
+ ret = -ENOMEM;
+ goto error_cleanup_dynamic;
+ }
+ }
+ }
+
+ buffer->scan_el_group.name = iio_scan_elements_group_name;
+
+ buffer->scan_el_group.attrs = kcalloc(attrcount + 1,
+ sizeof(buffer->scan_el_group.attrs[0]),
+ GFP_KERNEL);
+ if (buffer->scan_el_group.attrs == NULL) {
+ ret = -ENOMEM;
+ goto error_free_scan_mask;
+ }
+ if (buffer->scan_el_attrs)
+ memcpy(buffer->scan_el_group.attrs, buffer->scan_el_attrs,
+ sizeof(buffer->scan_el_group.attrs[0])*attrcount_orig);
+ attrn = attrcount_orig;
+
+ list_for_each_entry(p, &buffer->scan_el_dev_attr_list, l)
+ buffer->scan_el_group.attrs[attrn++] = &p->dev_attr.attr;
+ indio_dev->groups[indio_dev->groupcounter++] = &buffer->scan_el_group;
+
+ return 0;
+
+error_free_scan_mask:
+ kfree(buffer->scan_mask);
+error_cleanup_dynamic:
+ iio_free_chan_devattr_list(&buffer->scan_el_dev_attr_list);
+ kfree(indio_dev->buffer->buffer_group.attrs);
+
+ return ret;
+}
+
+void iio_buffer_free_sysfs_and_mask(struct iio_dev *indio_dev)
+{
+ if (!indio_dev->buffer)
+ return;
+
+ kfree(indio_dev->buffer->scan_mask);
+ kfree(indio_dev->buffer->buffer_group.attrs);
+ kfree(indio_dev->buffer->scan_el_group.attrs);
+ iio_free_chan_devattr_list(&indio_dev->buffer->scan_el_dev_attr_list);
+}
+
+/**
+ * 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);
+
+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);
+};
+EXPORT_SYMBOL_GPL(iio_scan_mask_query);
+
+/**
+ * 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 from;
+ unsigned to;
+ unsigned length;
+ struct list_head l;
+};
+
+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, POLLIN | POLLRDNORM);
+ return 0;
+}
+
+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);
+ }
+}
+
+
+int iio_push_to_buffers(struct iio_dev *indio_dev, const void *data)
+{
+ int ret;
+ struct iio_buffer *buf;
+
+ list_for_each_entry(buf, &indio_dev->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);
+
+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 == NULL)
+ 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)
+{
+ const struct iio_chan_spec *ch;
+ int ret, in_ind = -1, out_ind, length;
+ unsigned 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) {
+ in_ind = find_next_bit(indio_dev->active_scan_mask,
+ indio_dev->masklength,
+ in_ind + 1);
+ ch = iio_find_channel_from_si(indio_dev, in_ind);
+ if (ch->scan_type.repeat > 1)
+ length = ch->scan_type.storagebits / 8 *
+ ch->scan_type.repeat;
+ else
+ length = ch->scan_type.storagebits / 8;
+ /* Make sure we are aligned */
+ in_loc = roundup(in_loc, length) + length;
+ }
+ ch = iio_find_channel_from_si(indio_dev, in_ind);
+ if (ch->scan_type.repeat > 1)
+ length = ch->scan_type.storagebits / 8 *
+ ch->scan_type.repeat;
+ else
+ length = ch->scan_type.storagebits / 8;
+ 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) {
+ ch = iio_find_channel_from_si(indio_dev,
+ indio_dev->scan_index_timestamp);
+ if (ch->scan_type.repeat > 1)
+ length = ch->scan_type.storagebits / 8 *
+ ch->scan_type.repeat;
+ else
+ length = ch->scan_type.storagebits / 8;
+ 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;
+ }
+ buffer->demux_bounce = kzalloc(out_loc, GFP_KERNEL);
+ if (buffer->demux_bounce == NULL) {
+ ret = -ENOMEM;
+ goto error_clear_mux_table;
+ }
+ return 0;
+
+error_clear_mux_table:
+ iio_buffer_demux_free(buffer);
+
+ return ret;
+}
+
+int iio_update_demux(struct iio_dev *indio_dev)
+{
+ struct iio_buffer *buffer;
+ int ret;
+
+ list_for_each_entry(buffer, &indio_dev->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, &indio_dev->buffer_list, buffer_list)
+ iio_buffer_demux_free(buffer);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(iio_update_demux);
+
+/**
+ * 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);