nic_buffers/
lib.rs

1#![no_std]
2
3/// Error type for DMA allocation failures.
4#[derive(Debug, Clone, Copy, PartialEq, Eq)]
5pub struct DmaAllocError;
6
7#[derive(Clone, Copy)]
8pub struct DmaRegion {
9    pub phys: u64,
10    pub virt: *mut u8,
11    pub size: usize,
12}
13
14// SAFETY: DmaRegion contains only a physical address, a raw pointer, and a size.
15// It is safe to send across threads because the underlying DMA memory is
16// accessed only through the allocator's synchronization guarantees.
17unsafe impl Send for DmaRegion {}
18// SAFETY: DmaRegion is safe to share between threads for the same reasons
19// as Send above; concurrent access is controlled by the allocator.
20unsafe impl Sync for DmaRegion {}
21
22impl DmaRegion {
23    pub const ZERO: Self = Self {
24        phys: 0,
25        virt: core::ptr::null_mut(),
26        size: 0,
27    };
28
29    /// Returns whether null.
30    pub fn is_null(&self) -> bool {
31        self.virt.is_null()
32    }
33}
34
35pub trait DmaAllocator {
36    /// Allocates dma.
37    fn alloc_dma(&self, size: usize) -> Result<DmaRegion, DmaAllocError>;
38    /// # Safety
39    ///
40    /// The caller must ensure that `region` was previously allocated by this
41    /// allocator and has not already been freed.
42    unsafe fn free_dma(&self, region: DmaRegion);
43}
nic_buffers/lib.rs

nic_buffers/
lib.rs
