1 files changed, 196 insertions, 77 deletions

diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio-buffer.c
index e73033f3839a..7f9152c3c4d3 100644
--- a/drivers/iio/industrialio-buffer.c
+++ b/drivers/iio/industrialio-buffer.c
@@ -20,6 +20,7 @@
 #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"
@@ -31,16 +32,9 @@ static const char * const iio_endian_prefix[] = {
 	[IIO_LE] = "le",
 };
 
-static bool iio_buffer_is_active(struct iio_dev *indio_dev,
-				 struct iio_buffer *buf)
+static bool iio_buffer_is_active(struct iio_buffer *buf)
 {
-	struct list_head *p;
-
-	list_for_each(p, &indio_dev->buffer_list)
-		if (p == &buf->buffer_list)
-			return true;
-
-	return false;
+	return !list_empty(&buf->buffer_list);
 }
 
 /**
@@ -55,6 +49,9 @@ ssize_t iio_buffer_read_first_n_outer(struct file *filp, char __user *buf,
 	struct iio_dev *indio_dev = filp->private_data;
 	struct iio_buffer *rb = indio_dev->buffer;
 
+	if (!indio_dev->info)
+		return -ENODEV;
+
 	if (!rb || !rb->access->read_first_n)
 		return -EINVAL;
 	return rb->access->read_first_n(rb, n, buf);
@@ -69,6 +66,9 @@ unsigned int iio_buffer_poll(struct file *filp,
 	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 (rb->stufftoread)
 		return POLLIN | POLLRDNORM;
@@ -76,10 +76,27 @@ unsigned int iio_buffer_poll(struct file *filp,
 	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);
 }
 EXPORT_SYMBOL(iio_buffer_init);
 
@@ -146,7 +163,7 @@ static ssize_t iio_scan_el_store(struct device *dev,
 	if (ret < 0)
 		return ret;
 	mutex_lock(&indio_dev->mlock);
-	if (iio_buffer_is_active(indio_dev, indio_dev->buffer)) {
+	if (iio_buffer_is_active(indio_dev->buffer)) {
 		ret = -EBUSY;
 		goto error_ret;
 	}
@@ -192,7 +209,7 @@ static ssize_t iio_scan_el_ts_store(struct device *dev,
 		return ret;
 
 	mutex_lock(&indio_dev->mlock);
-	if (iio_buffer_is_active(indio_dev, indio_dev->buffer)) {
+	if (iio_buffer_is_active(indio_dev->buffer)) {
 		ret = -EBUSY;
 		goto error_ret;
 	}
@@ -214,7 +231,7 @@ static int iio_buffer_add_channel_sysfs(struct iio_dev *indio_dev,
 				     &iio_show_scan_index,
 				     NULL,
 				     0,
-				     0,
+				     IIO_SEPARATE,
 				     &indio_dev->dev,
 				     &buffer->scan_el_dev_attr_list);
 	if (ret)
@@ -249,29 +266,14 @@ static int iio_buffer_add_channel_sysfs(struct iio_dev *indio_dev,
 					     0,
 					     &indio_dev->dev,
 					     &buffer->scan_el_dev_attr_list);
+	if (ret)
+		goto error_ret;
 	attrcount++;
 	ret = attrcount;
 error_ret:
 	return ret;
 }
 
-static void iio_buffer_remove_and_free_scan_dev_attr(struct iio_dev *indio_dev,
-						     struct iio_dev_attr *p)
-{
-	kfree(p->dev_attr.attr.name);
-	kfree(p);
-}
-
-static void __iio_buffer_attr_cleanup(struct iio_dev *indio_dev)
-{
-	struct iio_dev_attr *p, *n;
-	struct iio_buffer *buffer = indio_dev->buffer;
-
-	list_for_each_entry_safe(p, n,
-				 &buffer->scan_el_dev_attr_list, l)
-		iio_buffer_remove_and_free_scan_dev_attr(indio_dev, p);
-}
-
 static const char * const iio_scan_elements_group_name = "scan_elements";
 
 int iio_buffer_register(struct iio_dev *indio_dev,
@@ -348,7 +350,7 @@ int iio_buffer_register(struct iio_dev *indio_dev,
 error_free_scan_mask:
 	kfree(buffer->scan_mask);
 error_cleanup_dynamic:
-	__iio_buffer_attr_cleanup(indio_dev);
+	iio_free_chan_devattr_list(&buffer->scan_el_dev_attr_list);
 
 	return ret;
 }
@@ -358,7 +360,7 @@ void iio_buffer_unregister(struct iio_dev *indio_dev)
 {
 	kfree(indio_dev->buffer->scan_mask);
 	kfree(indio_dev->buffer->scan_el_group.attrs);
-	__iio_buffer_attr_cleanup(indio_dev);
+	iio_free_chan_devattr_list(&indio_dev->buffer->scan_el_dev_attr_list);
 }
 EXPORT_SYMBOL(iio_buffer_unregister);
 
@@ -396,7 +398,7 @@ ssize_t iio_buffer_write_length(struct device *dev,
 			return len;
 
 	mutex_lock(&indio_dev->mlock);
-	if (iio_buffer_is_active(indio_dev, indio_dev->buffer)) {
+	if (iio_buffer_is_active(indio_dev->buffer)) {
 		ret = -EBUSY;
 	} else {
 		if (buffer->access->set_length)
@@ -414,13 +416,11 @@ ssize_t iio_buffer_show_enable(struct device *dev,
 			       char *buf)
 {
 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
-	return sprintf(buf, "%d\n",
-		       iio_buffer_is_active(indio_dev,
-					    indio_dev->buffer));
+	return sprintf(buf, "%d\n", iio_buffer_is_active(indio_dev->buffer));
 }
 EXPORT_SYMBOL(iio_buffer_show_enable);
 
-/* note NULL used as error indicator as it doesn't make sense. */
+/* 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)
@@ -435,8 +435,8 @@ static const unsigned long *iio_scan_mask_match(const unsigned long *av_masks,
 	return NULL;
 }
 
-static int iio_compute_scan_bytes(struct iio_dev *indio_dev, const long *mask,
-				  bool timestamp)
+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;
@@ -460,7 +460,56 @@ static int iio_compute_scan_bytes(struct iio_dev *indio_dev, const long *mask,
 	return bytes;
 }
 
-int iio_update_buffers(struct iio_dev *indio_dev,
+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);
+	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)
 {
@@ -490,9 +539,9 @@ int iio_update_buffers(struct iio_dev *indio_dev,
 		indio_dev->active_scan_mask = NULL;
 
 	if (remove_buffer)
-		list_del(&remove_buffer->buffer_list);
+		iio_buffer_deactivate(remove_buffer);
 	if (insert_buffer)
-		list_add(&insert_buffer->buffer_list, &indio_dev->buffer_list);
+		iio_buffer_activate(indio_dev, insert_buffer);
 
 	/* If no buffers in list, we are done */
 	if (list_empty(&indio_dev->buffer_list)) {
@@ -502,7 +551,7 @@ int iio_update_buffers(struct iio_dev *indio_dev,
 		return 0;
 	}
 
-	/* What scan mask do we actually have ?*/
+	/* What scan mask do we actually have? */
 	compound_mask = kcalloc(BITS_TO_LONGS(indio_dev->masklength),
 				sizeof(long), GFP_KERNEL);
 	if (compound_mask == NULL) {
@@ -527,9 +576,16 @@ int iio_update_buffers(struct iio_dev *indio_dev,
 			 * Roll back.
 			 * Note can only occur when adding a buffer.
 			 */
-			list_del(&insert_buffer->buffer_list);
-			indio_dev->active_scan_mask = old_mask;
-			success = -EINVAL;
+			iio_buffer_deactivate(insert_buffer);
+			if (old_mask) {
+				indio_dev->active_scan_mask = old_mask;
+				success = -EINVAL;
+			}
+			else {
+				kfree(compound_mask);
+				ret = -EINVAL;
+				goto error_ret;
+			}
 		}
 	} else {
 		indio_dev->active_scan_mask = compound_mask;
@@ -550,7 +606,8 @@ int iio_update_buffers(struct iio_dev *indio_dev,
 		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)
+	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) {
@@ -559,6 +616,7 @@ int iio_update_buffers(struct iio_dev *indio_dev,
 				goto error_run_postdisable;
 			}
 		}
+	}
 	if (indio_dev->info->update_scan_mode) {
 		ret = indio_dev->info
 			->update_scan_mode(indio_dev,
@@ -568,7 +626,7 @@ int iio_update_buffers(struct iio_dev *indio_dev,
 			goto error_run_postdisable;
 		}
 	}
-	/* Definitely possible for devices to support both of these.*/
+	/* Definitely possible for devices to support both of these. */
 	if (indio_dev->modes & INDIO_BUFFER_TRIGGERED) {
 		if (!indio_dev->trig) {
 			printk(KERN_INFO "Buffer not started: no trigger\n");
@@ -579,7 +637,7 @@ int iio_update_buffers(struct iio_dev *indio_dev,
 		indio_dev->currentmode = INDIO_BUFFER_TRIGGERED;
 	} else if (indio_dev->modes & INDIO_BUFFER_HARDWARE) {
 		indio_dev->currentmode = INDIO_BUFFER_HARDWARE;
-	} else { /* should never be reached */
+	} else { /* Should never be reached */
 		ret = -EINVAL;
 		goto error_run_postdisable;
 	}
@@ -611,13 +669,50 @@ error_run_postdisable:
 error_remove_inserted:
 
 	if (insert_buffer)
-		list_del(&insert_buffer->buffer_list);
+		iio_buffer_deactivate(insert_buffer);
 	indio_dev->active_scan_mask = old_mask;
 	kfree(compound_mask);
 error_ret:
 
 	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);
 
 ssize_t iio_buffer_store_enable(struct device *dev,
@@ -628,7 +723,6 @@ ssize_t iio_buffer_store_enable(struct device *dev,
 	int ret;
 	bool requested_state;
 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
-	struct iio_buffer *pbuf = indio_dev->buffer;
 	bool inlist;
 
 	ret = strtobool(buf, &requested_state);
@@ -638,16 +732,16 @@ ssize_t iio_buffer_store_enable(struct device *dev,
 	mutex_lock(&indio_dev->mlock);
 
 	/* Find out if it is in the list */
-	inlist = iio_buffer_is_active(indio_dev, pbuf);
+	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,
+		ret = __iio_update_buffers(indio_dev,
 					 indio_dev->buffer, NULL);
 	else
-		ret = iio_update_buffers(indio_dev,
+		ret = __iio_update_buffers(indio_dev,
 					 NULL, indio_dev->buffer);
 
 	if (ret < 0)
@@ -658,24 +752,6 @@ done:
 }
 EXPORT_SYMBOL(iio_buffer_store_enable);
 
-int iio_sw_buffer_preenable(struct iio_dev *indio_dev)
-{
-	struct iio_buffer *buffer;
-	unsigned bytes;
-	dev_dbg(&indio_dev->dev, "%s\n", __func__);
-
-	list_for_each_entry(buffer, &indio_dev->buffer_list, buffer_list)
-		if (buffer->access->set_bytes_per_datum) {
-			bytes = iio_compute_scan_bytes(indio_dev,
-						       buffer->scan_mask,
-						       buffer->scan_timestamp);
-
-			buffer->access->set_bytes_per_datum(buffer, bytes);
-		}
-	return 0;
-}
-EXPORT_SYMBOL(iio_sw_buffer_preenable);
-
 /**
  * iio_validate_scan_mask_onehot() - Validates that exactly one channel is selected
  * @indio_dev: the iio device
@@ -703,6 +779,7 @@ static bool iio_validate_scan_mask(struct iio_dev *indio_dev,
 
 /**
  * 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.
  *
@@ -723,7 +800,7 @@ int iio_scan_mask_set(struct iio_dev *indio_dev,
 	if (trialmask == NULL)
 		return -ENOMEM;
 	if (!indio_dev->masklength) {
-		WARN_ON("trying to set scanmask prior to registering buffer\n");
+		WARN_ON("Trying to set scanmask prior to registering buffer\n");
 		goto err_invalid_mask;
 	}
 	bitmap_copy(trialmask, buffer->scan_mask, indio_dev->masklength);
@@ -778,8 +855,8 @@ struct iio_demux_table {
 	struct list_head l;
 };
 
-static unsigned char *iio_demux(struct iio_buffer *buffer,
-				 unsigned char *datain)
+static const void *iio_demux(struct iio_buffer *buffer,
+				 const void *datain)
 {
 	struct iio_demux_table *t;
 
@@ -792,9 +869,9 @@ static unsigned char *iio_demux(struct iio_buffer *buffer,
 	return buffer->demux_bounce;
 }
 
-static int iio_push_to_buffer(struct iio_buffer *buffer, unsigned char *data)
+static int iio_push_to_buffer(struct iio_buffer *buffer, const void *data)
 {
-	unsigned char *dataout = iio_demux(buffer, data);
+	const void *dataout = iio_demux(buffer, data);
 
 	return buffer->access->store_to(buffer, dataout);
 }
@@ -809,7 +886,7 @@ static void iio_buffer_demux_free(struct iio_buffer *buffer)
 }
 
 
-int iio_push_to_buffers(struct iio_dev *indio_dev, unsigned char *data)
+int iio_push_to_buffers(struct iio_dev *indio_dev, const void *data)
 {
 	int ret;
 	struct iio_buffer *buf;
@@ -932,3 +1009,45 @@ error_clear_mux_table:
 	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);