Struct DmaMask

pub struct DmaMask(/* private fields */);

A DMA mask that holds a bitmask with the lowest n bits set.

Use DmaMask::new or DmaMask::try_new to construct a value. Values are guaranteed to never exceed the bit width of u64.

This is the Rust equivalent of the C macro DMA_BIT_MASK().

Implementations

impl DmaMask

pub const fn new<const N: u32>() -> Self

Constructs a DmaMask with the lowest n bits set to 1.

For n <= 64, sets exactly the lowest n bits. For n > 64, results in a build error.

Examples

use kernel::dma::DmaMask;

let mask0 = DmaMask::new::<0>();
assert_eq!(mask0.value(), 0);

let mask1 = DmaMask::new::<1>();
assert_eq!(mask1.value(), 0b1);

let mask64 = DmaMask::new::<64>();
assert_eq!(mask64.value(), u64::MAX);

// Build failure.
// let mask_overflow = DmaMask::new::<100>();

pub const fn try_new(n: u32) -> Result<Self>

Constructs a DmaMask with the lowest n bits set to 1.

For n <= 64, sets exactly the lowest n bits. For n > 64, returns EINVAL.

Examples

use kernel::dma::DmaMask;

let mask0 = DmaMask::try_new(0)?;
assert_eq!(mask0.value(), 0);

let mask1 = DmaMask::try_new(1)?;
assert_eq!(mask1.value(), 0b1);

let mask64 = DmaMask::try_new(64)?;
assert_eq!(mask64.value(), u64::MAX);

let mask_overflow = DmaMask::try_new(100);
assert!(mask_overflow.is_err());

pub const fn value(&self) -> u64

Returns the underlying u64 bitmask value.

Trait Implementations

impl Clone for DmaMask

fn clone(&self) -> DmaMask

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for DmaMask

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

Formats the value using the given formatter.

impl PartialEq for DmaMask

fn eq(&self, other: &DmaMask) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Copy for DmaMask

impl Eq for DmaMask

impl StructuralPartialEq for DmaMask