include/linux/iio/buffer-dma.h

Source file repositories/reference/linux-study-clean/include/linux/iio/buffer-dma.h

File Facts

System
Linux kernel
Corpus path
include/linux/iio/buffer-dma.h
Extension
.h
Size
6079 bytes
Lines
184
Domain
Core OS
Bucket
Core Kernel Interface
Inferred role
Core OS: implementation source
Status
source implementation candidate

Why This File Exists

Core operating-system implementation surface: boot, tasks, memory, VFS, syscall-facing interfaces, synchronization, credentials, and isolation.

Dependency Surface

Detected Declarations

Annotated Snippet

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;

	bool cyclic;
	bool fileio;

	struct sg_table *sg_table;
	struct dma_fence *fence;
};

/**
 * 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
 * @next_dequeue: index of next block that will be dequeued
 * @enabled: Whether the buffer is operating in fileio mode
 */
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;

	unsigned int next_dequeue;
	bool enabled;
};

/**
 * 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
 * @active: Whether the buffer is currently active
 * @num_dmabufs: Total number of DMABUFs attached to this queue
 * @fileio: FileIO state
 */
struct iio_dma_buffer_queue {
	struct iio_buffer buffer;
	struct device *dev;
	const struct iio_dma_buffer_ops *ops;

	/*
	 * A mutex to protect accessing, configuring (eg: enqueuing DMA blocks)
	 * and do file IO on struct iio_dma_buffer_queue objects.
	 */
	struct mutex lock;
	/* A spin lock to protect adding/removing blocks to the queue list */
	spinlock_t list_lock;
	struct list_head incoming;

	bool active;
	atomic_t num_dmabufs;

	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 {

Annotation

Implementation Notes