Struct DmaStream

pub struct DmaStream {
    inner: Arc<DmaStreamInner>,
}

A streaming DMA mapping. Users must synchronize data before reading or after writing to ensure consistency.

The mapping is automatically destroyed when this object is dropped.

Fields

inner: Arc<DmaStreamInner>

Implementations

impl DmaStream

pub fn map( segment: USegment, direction: DmaDirection, is_cache_coherent: bool, ) -> Result<Self, DmaError>

Establishes DMA stream mapping for a given USegment.

The method fails if the segment already belongs to a DMA mapping.

pub fn segment(&self) -> &USegment

Gets the underlying USegment.

Usually, the CPU side should not access the memory after the DMA mapping is established because there is a chance that the device is updating the memory. Do this at your own risk.

pub fn nframes(&self) -> usize

Returns the number of frames.

pub fn nbytes(&self) -> usize

Returns the number of bytes.

pub fn direction(&self) -> DmaDirection

Returns the DMA direction.

pub fn sync(&self, _byte_range: Range<usize>) -> Result<(), Error>

Synchronizes the streaming DMA mapping with the device.

This method should be called under one of the two conditions:

1. The data of the stream DMA mapping has been updated by the device side. The CPU side needs to call the sync method before reading data (e.g., using read_bytes).
2. The data of the stream DMA mapping has been updated by the CPU side (e.g., using write_bytes). Before the CPU side notifies the device side to read, it must call the sync method first.

impl<'a> DmaStream

pub fn reader(&'a self) -> Result<VmReader<'a, Infallible>, Error>

Returns a reader to read data from it.

pub fn writer(&'a self) -> Result<VmWriter<'a, Infallible>, Error>

Returns a writer to write data into it.

Trait Implementations

impl AsRef<DmaStream> for DmaStream

fn as_ref(&self) -> &DmaStream

Converts this type into a shared reference of the (usually inferred) input type.

impl Clone for DmaStream

fn clone(&self) -> DmaStream

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for DmaStream

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl HasDaddr for DmaStream

fn daddr(&self) -> Daddr

Gets the base address of the mapping in the device address space.

impl HasPaddr for DmaStream

fn paddr(&self) -> Paddr

Returns the physical address.

impl VmIo for DmaStream

fn read(&self, offset: usize, writer: &mut VmWriter<'_>) -> Result<(), Error>

Reads data into the buffer.

fn write(&self, offset: usize, reader: &mut VmReader<'_>) -> Result<(), Error>

Writes data from the buffer.

fn read_bytes(&self, offset: usize, buf: &mut [u8]) -> Result<()>

Reads a specified number of bytes at a specified offset into a given buffer.

fn read_val<T: Pod>(&self, offset: usize) -> Result<T>

Reads a value of a specified type at a specified offset.

fn read_slice<T: Pod>(&self, offset: usize, slice: &mut [T]) -> Result<()>

Reads a slice of a specified type at a specified offset.

fn write_bytes(&self, offset: usize, buf: &[u8]) -> Result<()>

Writes a specified number of bytes from a given buffer at a specified offset.

fn write_val<T: Pod>(&self, offset: usize, new_val: &T) -> Result<()>

Writes a value of a specified type at a specified offset.

fn write_slice<T: Pod>(&self, offset: usize, slice: &[T]) -> Result<()>

Writes a slice of a specified type at a specified offset.

fn write_vals<'a, T: Pod + 'a, I: Iterator<Item = &'a T>>( &self, offset: usize, iter: I, align: usize, ) -> Result<usize>

Writes a sequence of values given by an iterator (iter) from the specified offset (offset).