[PATCH v11 0/3] Add dma coherent allocator abstraction

Abdiel Janulgue
2025-01-23T10:43:50Z

Changes since v10:
- rename read() to as_slice() (Boqun Feng)
- Do a bitwise copy of ARef<Device> in into_parts() when returning the
device reference (Alice Ryhl).
- Link to v10: https://lore.kernel.org/all/20250121191432.1178734-1-abdiel.janulgue@gmail.com/

Changes since v9:
- Use ARef<Device> in the constructor arguments, docs clarification avoid
manually dropping the refcount for the device in into_parts(), use
add() instead of wrapping_add() in the pointer arithmetic for performance
(Alice Ryhl).

Changes since v8:
- Add MAINTAINERS entry
- Fix build issues due to switch from core::ffi to crate:ffi in bindgen.
- Ensure the wrapped attribute is non-pub in struct Attrs, declare it
#[repr(transparent)] as well (Daniel Sedlak)

Changes since v7:
- Remove cpu_buf() and cpu_buf_mut() as exporting a r/w interface via
a slice is undefined behaviour due to slice's requirement that the
underlying pointer should not be modified (Alice Ryhl, Robin Murphy).
- Reintroduce r/w helpers instead which includes proper safety
invariants (Daniel Almeida).

Changes since v6:
- Include the dma_attrs in the constructor, use alloc::Flags as inpiration

Changes since v5:
- Remove unnecessary lifetime annotation when returning the CPU buffer.

Changes since v4:
- Documentation and example fixes, use Markdown formatting (Miguel Ojeda).
- Discard read()/write() helpers to remove bound on Copy and fix overhead
(Daniel Almeida).
- Improve error-handling in the constructor block (Andreas Hindborg).

Changes since v3:
- Reject ZST types by checking the type size in the constructor in
addition to requiring FromBytes/AsBytes traits for the type (Alice Ryhl).

Changes since v2:
- Fixed missing header for generating the bindings.

Changes since v1:
- Fix missing info in commit log where EOVERFLOW is used.
- Restrict the dma coherent allocator to numeric types for now for valid
behaviour (Daniel Almeida).
- Build slice dynamically.

Abdiel Janulgue (3):
rust: error: Add EOVERFLOW
rust: add dma coherent allocator abstraction.
MAINTAINERS: add entry for Rust dma mapping helpers device driver API

MAINTAINERS | 10 ++
rust/bindings/bindings_helper.h | 1 +
rust/kernel/dma.rs | 282 ++++++++++++++++++++++++++++++++
rust/kernel/error.rs | 1 +
rust/kernel/lib.rs | 1 +
5 files changed, 295 insertions(+)
create mode 100644 rust/kernel/dma.rs

base-commit: ceff0757f5dafb5be5205988171809c877b1d3e3
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2.43.0