Struct DmaBuffer

pub struct DmaBuffer {
    cpu_ptr: *mut u8,
    bus_addr: u64,
    capacity: usize,
    ownership: BufferOwnership,
    index: u16,
}

A single DMA buffer with ownership tracking.

Tracks both CPU and bus addresses, plus ownership state.

Fields

cpu_ptr: *mut u8

CPU-accessible pointer to buffer data.

bus_addr: u64

Device-visible bus address.

capacity: usize

Buffer capacity in bytes.

ownership: BufferOwnership

Current ownership state.

index: u16

Buffer index within the pool.

Implementations

impl DmaBuffer

pub unsafe fn new( cpu_ptr: *mut u8, bus_addr: u64, capacity: usize, index: u16, ) -> Self

Create a new DMA buffer.

Safety

• cpu_ptr must point to valid DMA-capable memory
• bus_addr must be the corresponding device-visible address

pub fn as_slice(&self) -> &[u8]

Get buffer data as slice.

Panics

Panics if buffer is not DriverOwned.

pub fn as_mut_slice(&mut self) -> &mut [u8]

Get buffer data as mutable slice.

Panics

Panics if buffer is not DriverOwned.

pub fn as_mut_slice_len(&mut self, len: usize) -> &mut [u8]

Get the first len bytes as mutable slice.

Panics

Panics if buffer is not DriverOwned or len > capacity.

pub fn bus_addr(&self) -> u64

Get the device-visible bus address.

pub fn cpu_ptr(&self) -> *mut u8

Get the CPU pointer.

pub fn index(&self) -> u16

Get buffer index.

pub fn capacity(&self) -> usize

Get buffer capacity.

pub fn ownership(&self) -> BufferOwnership

Get current ownership state.

pub fn is_free(&self) -> bool

Check if buffer can be allocated.

pub fn is_driver_owned(&self) -> bool

Check if buffer is owned by driver.

pub fn is_device_owned(&self) -> bool

Check if buffer is owned by device.

pub(crate) unsafe fn mark_allocated(&mut self)

Mark buffer as allocated (Free -> DriverOwned).

Safety

Only call during allocation from pool.

pub unsafe fn mark_device_owned(&mut self)

Mark buffer as device-owned (DriverOwned -> DeviceOwned).

Safety

Only call immediately before submitting to device.

pub unsafe fn mark_driver_owned(&mut self)

Mark buffer as driver-owned (DeviceOwned -> DriverOwned).

Safety

Only call after device confirms ownership transfer (poll completion).

pub(crate) unsafe fn mark_free(&mut self)

Mark buffer as free (DriverOwned -> Free).

Safety

Only call during return to pool.

Trait Implementations

impl Send for DmaBuffer

impl Sync for DmaBuffer