Struct DmaBufferPool

pub struct DmaBufferPool { /* private fields */ }

A DMA buffer pool.

This struct manages a pool of buffers. Unlike a Vec-based buffers, this struct provides a way to know the physical memory address of a buffer so that it can be passed to a device for DMA operations.

Future Work

• Distinguish the physical memory address and device memory address. Some computers might have different address spaces for devices, and some might have IOMMU to translate the addresses.

Example

const BUFFER_SIZE: usize = 4096;
const NUM_BUFFERS: usize = 16;

let mut pool = DmaBufferPool::new(BUFFER_SIZE, NUM_BUFFERS);
let buffer_id = pool.allocate().unwrap();

let paddr = pool.paddr(buffer_id);
let vaddr = pool.vaddr(buffer_id);

// Do DMA operations here!

pool.free(buffer_id);

Implementations

impl DmaBufferPool

pub fn new(buffer_size: usize, num_buffers: usize) -> DmaBufferPool

pub fn allocate(&mut self) -> Option<BufferId>

Allocates a buffer.

pub fn free(&mut self, index: BufferId)

Frees a buffer.

pub fn paddr_to_id(&self, paddr: PAddr) -> Option<BufferId>

Converts a physical memory address to a buffer index.

pub fn vaddr(&self, index: BufferId) -> VAddr

Returns the virtual memory address of a buffer.

pub fn paddr(&self, index: BufferId) -> PAddr

Returns the physical memory address of a buffer.