Struct ostd::mm::DmaStream

pub struct DmaStream { /* private fields */ }

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.

Implementations

impl DmaStream

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

Establishes DMA stream mapping for a given Segment.

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

pub fn vm_segment(&self) -> &Segment

Gets the underlying Segment.

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 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>, Error>

Returns a reader to read data from it.

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

Returns a writer to write data into it.

Trait Implementations

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

Reads data into the buffer.

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

Writes data from the 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_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).