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-rw-r--r--include/linux/iio/buffer-dma.h152
1 files changed, 152 insertions, 0 deletions
diff --git a/include/linux/iio/buffer-dma.h b/include/linux/iio/buffer-dma.h
new file mode 100644
index 000000000..767467d88
--- /dev/null
+++ b/include/linux/iio/buffer-dma.h
@@ -0,0 +1,152 @@
+/*
+ * Copyright 2013-2015 Analog Devices Inc.
+ * Author: Lars-Peter Clausen <lars@metafoo.de>
+ *
+ * Licensed under the GPL-2.
+ */
+
+#ifndef __INDUSTRIALIO_DMA_BUFFER_H__
+#define __INDUSTRIALIO_DMA_BUFFER_H__
+
+#include <linux/list.h>
+#include <linux/kref.h>
+#include <linux/spinlock.h>
+#include <linux/mutex.h>
+#include <linux/iio/buffer.h>
+
+struct iio_dma_buffer_queue;
+struct iio_dma_buffer_ops;
+struct device;
+
+struct iio_buffer_block {
+ u32 size;
+ u32 bytes_used;
+};
+
+/**
+ * enum iio_block_state - State of a struct iio_dma_buffer_block
+ * @IIO_BLOCK_STATE_DEQUEUED: Block is not queued
+ * @IIO_BLOCK_STATE_QUEUED: Block is on the incoming queue
+ * @IIO_BLOCK_STATE_ACTIVE: Block is currently being processed by the DMA
+ * @IIO_BLOCK_STATE_DONE: Block is on the outgoing queue
+ * @IIO_BLOCK_STATE_DEAD: Block has been marked as to be freed
+ */
+enum iio_block_state {
+ IIO_BLOCK_STATE_DEQUEUED,
+ IIO_BLOCK_STATE_QUEUED,
+ IIO_BLOCK_STATE_ACTIVE,
+ IIO_BLOCK_STATE_DONE,
+ IIO_BLOCK_STATE_DEAD,
+};
+
+/**
+ * struct iio_dma_buffer_block - IIO buffer block
+ * @head: List head
+ * @size: Total size of the block in bytes
+ * @bytes_used: Number of bytes that contain valid data
+ * @vaddr: Virutal address of the blocks memory
+ * @phys_addr: Physical address of the blocks memory
+ * @queue: Parent DMA buffer queue
+ * @kref: kref used to manage the lifetime of block
+ * @state: Current state of the block
+ */
+struct iio_dma_buffer_block {
+ /* May only be accessed by the owner of the block */
+ struct list_head head;
+ size_t bytes_used;
+
+ /*
+ * Set during allocation, constant thereafter. May be accessed read-only
+ * by anybody holding a reference to the block.
+ */
+ void *vaddr;
+ dma_addr_t phys_addr;
+ size_t size;
+ struct iio_dma_buffer_queue *queue;
+
+ /* Must not be accessed outside the core. */
+ struct kref kref;
+ /*
+ * Must not be accessed outside the core. Access needs to hold
+ * queue->list_lock if the block is not owned by the core.
+ */
+ enum iio_block_state state;
+};
+
+/**
+ * struct iio_dma_buffer_queue_fileio - FileIO state for the DMA buffer
+ * @blocks: Buffer blocks used for fileio
+ * @active_block: Block being used in read()
+ * @pos: Read offset in the active block
+ * @block_size: Size of each block
+ */
+struct iio_dma_buffer_queue_fileio {
+ struct iio_dma_buffer_block *blocks[2];
+ struct iio_dma_buffer_block *active_block;
+ size_t pos;
+ size_t block_size;
+};
+
+/**
+ * struct iio_dma_buffer_queue - DMA buffer base structure
+ * @buffer: IIO buffer base structure
+ * @dev: Parent device
+ * @ops: DMA buffer callbacks
+ * @lock: Protects the incoming list, active and the fields in the fileio
+ * substruct
+ * @list_lock: Protects lists that contain blocks which can be modified in
+ * atomic context as well as blocks on those lists. This is the outgoing queue
+ * list and typically also a list of active blocks in the part that handles
+ * the DMA controller
+ * @incoming: List of buffers on the incoming queue
+ * @outgoing: List of buffers on the outgoing queue
+ * @active: Whether the buffer is currently active
+ * @fileio: FileIO state
+ */
+struct iio_dma_buffer_queue {
+ struct iio_buffer buffer;
+ struct device *dev;
+ const struct iio_dma_buffer_ops *ops;
+
+ struct mutex lock;
+ spinlock_t list_lock;
+ struct list_head incoming;
+ struct list_head outgoing;
+
+ bool active;
+
+ struct iio_dma_buffer_queue_fileio fileio;
+};
+
+/**
+ * struct iio_dma_buffer_ops - DMA buffer callback operations
+ * @submit: Called when a block is submitted to the DMA controller
+ * @abort: Should abort all pending transfers
+ */
+struct iio_dma_buffer_ops {
+ int (*submit)(struct iio_dma_buffer_queue *queue,
+ struct iio_dma_buffer_block *block);
+ void (*abort)(struct iio_dma_buffer_queue *queue);
+};
+
+void iio_dma_buffer_block_done(struct iio_dma_buffer_block *block);
+void iio_dma_buffer_block_list_abort(struct iio_dma_buffer_queue *queue,
+ struct list_head *list);
+
+int iio_dma_buffer_enable(struct iio_buffer *buffer,
+ struct iio_dev *indio_dev);
+int iio_dma_buffer_disable(struct iio_buffer *buffer,
+ struct iio_dev *indio_dev);
+int iio_dma_buffer_read(struct iio_buffer *buffer, size_t n,
+ char __user *user_buffer);
+size_t iio_dma_buffer_data_available(struct iio_buffer *buffer);
+int iio_dma_buffer_set_bytes_per_datum(struct iio_buffer *buffer, size_t bpd);
+int iio_dma_buffer_set_length(struct iio_buffer *buffer, int length);
+int iio_dma_buffer_request_update(struct iio_buffer *buffer);
+
+int iio_dma_buffer_init(struct iio_dma_buffer_queue *queue,
+ struct device *dma_dev, const struct iio_dma_buffer_ops *ops);
+void iio_dma_buffer_exit(struct iio_dma_buffer_queue *queue);
+void iio_dma_buffer_release(struct iio_dma_buffer_queue *queue);
+
+#endif