Enum DmaSubSliceMutImmut 

pub enum DmaSubSliceMutImmut<'a, T: ImmutableFromIntoBytes> {
    Immutable(DmaSubSlice<'a, T>),
    Mutable(DmaSubSliceMut<'a, T>),
}

A buffer that can be safely used for read-only DMA operations, backed by either a SubSliceMutImmut.

Creating a DmaSubSliceMutImmut over a SubSliceMutImmut ensures that all prior Rust writes to the active region of this slice are observable by any DMA operations initiated through an MMIO write operation, where that MMIO write is performed after constructing the DmaSubSliceMutImmut.

For this guarantee to hold, the DmaSubSliceMutImmut struct must exist for the duration of the entire DMA operation, until the Rust program has observed that the operation is complete (such as by reading a status bit in memory or an MMIO register).

DmaSliceMutImmut may wrap an immutable, shared Rust slice reference. Furthermore, in contrast to DmaSubSliceMut, DmaSubSliceMutImmut may not expose writes performed by a DMA operation back to Rust. As such, its contents must not be modified by the DMA operation. For a DMA operation that may write to the active range of the supplied sub slice, use DmaSubSliceMut instead.

Variants

Immutable(DmaSubSlice<'a, T>)

Mutable(DmaSubSliceMut<'a, T>)

Implementations

impl<'a, T: ImmutableFromIntoBytes> DmaSubSliceMutImmut<'a, T>

pub fn new( sub_slice: SubSliceMutImmut<'_, T>, fence: impl DmaFence, ) -> DmaSubSliceMutImmut<'_, T>

Create a DmaSubSliceMutImmut from a SubSliceMutImmut.

This function uses the supplied fence object to ensure that all prior writes to slice are exposed to any DMA operations initiated by an MMIO read or write operation after this function returns, and which finish before the resulting DmaSubSlice is dropped.

pub fn as_ptr(&self) -> *const T

Returns the pointer to the first element of the currently accessible portion of the wrapped SubSlice.

pub fn len(&self) -> usize

Returns the length of the currently accessible range of the wrapped SubSlice.

pub fn take(self) -> SubSliceMutImmut<'a, T>

Reconstruct the original SubSliceMutImmut.

This function must be called only when the Rust program has observed that the DMA operation over the buffer is complete (such as by reading a status bit in memory or an MMIO register). Otherwise, any future reads by the DMA peripheral may not be consistent with the buffer contents.

Trait Implementations

impl<'a, T: Debug + ImmutableFromIntoBytes> Debug for DmaSubSliceMutImmut<'a, T>

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

Formats the value using the given formatter.