rust: dma: implement dma::Device trait

Add a trait that defines the DMA specific methods of devices.

The `dma::Device` trait is to be implemented by bus device
representations, where the underlying bus is capable of DMA, such as
`pci::Device` or `platform::Device`.

Reviewed-by: Abdiel Janulgue <abdiel.janulgue@gmail.com>
Reviewed-by: Daniel Almeida <daniel.almeida@collabora.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20250716150354.51081-2-dakr@kernel.org
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
This commit is contained in:
Danilo Krummrich
2025-07-16 17:02:46 +02:00
parent 9a8682f087
commit d06d5f66f5

View File

@@ -5,14 +5,21 @@
//! C header: [`include/linux/dma-mapping.h`](srctree/include/linux/dma-mapping.h)
use crate::{
bindings, build_assert,
device::{Bound, Device},
bindings, build_assert, device,
device::Bound,
error::code::*,
error::Result,
transmute::{AsBytes, FromBytes},
types::ARef,
};
/// Trait to be implemented by DMA capable bus devices.
///
/// The [`dma::Device`](Device) trait should be implemented by bus specific device representations,
/// where the underlying bus is DMA capable, such as [`pci::Device`](::kernel::pci::Device) or
/// [`platform::Device`](::kernel::platform::Device).
pub trait Device: AsRef<device::Device<Core>> {}
/// Possible attributes associated with a DMA mapping.
///
/// They can be combined with the operators `|`, `&`, and `!`.
@@ -130,7 +137,7 @@ pub mod attrs {
// Hence, find a way to revoke the device resources of a `CoherentAllocation`, but not the
// entire `CoherentAllocation` including the allocated memory itself.
pub struct CoherentAllocation<T: AsBytes + FromBytes> {
dev: ARef<Device>,
dev: ARef<device::Device>,
dma_handle: bindings::dma_addr_t,
count: usize,
cpu_addr: *mut T,
@@ -152,7 +159,7 @@ impl<T: AsBytes + FromBytes> CoherentAllocation<T> {
/// # Ok::<(), Error>(()) }
/// ```
pub fn alloc_attrs(
dev: &Device<Bound>,
dev: &device::Device<Bound>,
count: usize,
gfp_flags: kernel::alloc::Flags,
dma_attrs: Attrs,
@@ -194,7 +201,7 @@ impl<T: AsBytes + FromBytes> CoherentAllocation<T> {
/// Performs the same functionality as [`CoherentAllocation::alloc_attrs`], except the
/// `dma_attrs` is 0 by default.
pub fn alloc_coherent(
dev: &Device<Bound>,
dev: &device::Device<Bound>,
count: usize,
gfp_flags: kernel::alloc::Flags,
) -> Result<CoherentAllocation<T>> {