1 files changed, 79 insertions, 21 deletions

diff --git a/drivers/iio/buffer/industrialio-buffer-dma.c b/drivers/iio/buffer/industrialio-buffer-dma.c
index 5610ba6792..13b1a85896 100644
--- a/drivers/iio/buffer/industrialio-buffer-dma.c
+++ b/drivers/iio/buffer/industrialio-buffer-dma.c
@@ -195,6 +195,18 @@ static void _iio_dma_buffer_block_done(struct iio_dma_buffer_block *block)
 		block->state = IIO_BLOCK_STATE_DONE;
 }
 
+static void iio_dma_buffer_queue_wake(struct iio_dma_buffer_queue *queue)
+{
+	__poll_t flags;
+
+	if (queue->buffer.direction == IIO_BUFFER_DIRECTION_IN)
+		flags = EPOLLIN | EPOLLRDNORM;
+	else
+		flags = EPOLLOUT | EPOLLWRNORM;
+
+	wake_up_interruptible_poll(&queue->buffer.pollq, flags);
+}
+
 /**
  * iio_dma_buffer_block_done() - Indicate that a block has been completed
  * @block: The completed block
@@ -212,7 +224,7 @@ void iio_dma_buffer_block_done(struct iio_dma_buffer_block *block)
 	spin_unlock_irqrestore(&queue->list_lock, flags);
 
 	iio_buffer_block_put_atomic(block);
-	wake_up_interruptible_poll(&queue->buffer.pollq, EPOLLIN | EPOLLRDNORM);
+	iio_dma_buffer_queue_wake(queue);
 }
 EXPORT_SYMBOL_GPL(iio_dma_buffer_block_done);
 
@@ -241,7 +253,7 @@ void iio_dma_buffer_block_list_abort(struct iio_dma_buffer_queue *queue,
 	}
 	spin_unlock_irqrestore(&queue->list_lock, flags);
 
-	wake_up_interruptible_poll(&queue->buffer.pollq, EPOLLIN | EPOLLRDNORM);
+	iio_dma_buffer_queue_wake(queue);
 }
 EXPORT_SYMBOL_GPL(iio_dma_buffer_block_list_abort);
 
@@ -335,8 +347,24 @@ int iio_dma_buffer_request_update(struct iio_buffer *buffer)
 			queue->fileio.blocks[i] = block;
 		}
 
-		block->state = IIO_BLOCK_STATE_QUEUED;
-		list_add_tail(&block->head, &queue->incoming);
+		/*
+		 * block->bytes_used may have been modified previously, e.g. by
+		 * iio_dma_buffer_block_list_abort(). Reset it here to the
+		 * block's so that iio_dma_buffer_io() will work.
+		 */
+		block->bytes_used = block->size;
+
+		/*
+		 * If it's an input buffer, mark the block as queued, and
+		 * iio_dma_buffer_enable() will submit it. Otherwise mark it as
+		 * done, which means it's ready to be dequeued.
+		 */
+		if (queue->buffer.direction == IIO_BUFFER_DIRECTION_IN) {
+			block->state = IIO_BLOCK_STATE_QUEUED;
+			list_add_tail(&block->head, &queue->incoming);
+		} else {
+			block->state = IIO_BLOCK_STATE_DONE;
+		}
 	}
 
 out_unlock:
@@ -488,20 +516,12 @@ static struct iio_dma_buffer_block *iio_dma_buffer_dequeue(
 	return block;
 }
 
-/**
- * iio_dma_buffer_read() - DMA buffer read callback
- * @buffer: Buffer to read form
- * @n: Number of bytes to read
- * @user_buffer: Userspace buffer to copy the data to
- *
- * Should be used as the read callback for iio_buffer_access_ops
- * struct for DMA buffers.
- */
-int iio_dma_buffer_read(struct iio_buffer *buffer, size_t n,
-	char __user *user_buffer)
+static int iio_dma_buffer_io(struct iio_buffer *buffer, size_t n,
+			     char __user *user_buffer, bool is_from_user)
 {
 	struct iio_dma_buffer_queue *queue = iio_buffer_to_queue(buffer);
 	struct iio_dma_buffer_block *block;
+	void *addr;
 	int ret;
 
 	if (n < buffer->bytes_per_datum)
@@ -524,8 +544,13 @@ int iio_dma_buffer_read(struct iio_buffer *buffer, size_t n,
 	n = rounddown(n, buffer->bytes_per_datum);
 	if (n > block->bytes_used - queue->fileio.pos)
 		n = block->bytes_used - queue->fileio.pos;
+	addr = block->vaddr + queue->fileio.pos;
 
-	if (copy_to_user(user_buffer, block->vaddr + queue->fileio.pos, n)) {
+	if (is_from_user)
+		ret = copy_from_user(addr, user_buffer, n);
+	else
+		ret = copy_to_user(user_buffer, addr, n);
+	if (ret) {
 		ret = -EFAULT;
 		goto out_unlock;
 	}
@@ -544,16 +569,49 @@ out_unlock:
 
 	return ret;
 }
+
+/**
+ * iio_dma_buffer_read() - DMA buffer read callback
+ * @buffer: Buffer to read form
+ * @n: Number of bytes to read
+ * @user_buffer: Userspace buffer to copy the data to
+ *
+ * Should be used as the read callback for iio_buffer_access_ops
+ * struct for DMA buffers.
+ */
+int iio_dma_buffer_read(struct iio_buffer *buffer, size_t n,
+			char __user *user_buffer)
+{
+	return iio_dma_buffer_io(buffer, n, user_buffer, false);
+}
 EXPORT_SYMBOL_GPL(iio_dma_buffer_read);
 
 /**
- * iio_dma_buffer_data_available() - DMA buffer data_available callback
- * @buf: Buffer to check for data availability
+ * iio_dma_buffer_write() - DMA buffer write callback
+ * @buffer: Buffer to read form
+ * @n: Number of bytes to read
+ * @user_buffer: Userspace buffer to copy the data from
  *
- * Should be used as the data_available callback for iio_buffer_access_ops
+ * Should be used as the write callback for iio_buffer_access_ops
  * struct for DMA buffers.
  */
-size_t iio_dma_buffer_data_available(struct iio_buffer *buf)
+int iio_dma_buffer_write(struct iio_buffer *buffer, size_t n,
+			 const char __user *user_buffer)
+{
+	return iio_dma_buffer_io(buffer, n,
+				 (__force __user char *)user_buffer, true);
+}
+EXPORT_SYMBOL_GPL(iio_dma_buffer_write);
+
+/**
+ * iio_dma_buffer_usage() - DMA buffer data_available and
+ * space_available callback
+ * @buf: Buffer to check for data availability
+ *
+ * Should be used as the data_available and space_available callbacks for
+ * iio_buffer_access_ops struct for DMA buffers.
+ */
+size_t iio_dma_buffer_usage(struct iio_buffer *buf)
 {
 	struct iio_dma_buffer_queue *queue = iio_buffer_to_queue(buf);
 	struct iio_dma_buffer_block *block;
@@ -586,7 +644,7 @@ size_t iio_dma_buffer_data_available(struct iio_buffer *buf)
 
 	return data_available;
 }
-EXPORT_SYMBOL_GPL(iio_dma_buffer_data_available);
+EXPORT_SYMBOL_GPL(iio_dma_buffer_usage);
 
 /**
  * iio_dma_buffer_set_bytes_per_datum() - DMA buffer set_bytes_per_datum callback