rust: mem: add `AsRepr` and `AsReprMut`

Some API like atomics and I/O operate on primitives only; therefore other
types would need to converted to these primitive first. Add two traits
`AsRepr` and `AsReprMut` to indicate that the type can be turned into a
primitive for these operations.

`T: AsRepr` means that `&T` can be viewed as `&T::Repr` and thus it needs
to support transmutability in one direction. `T: AsReprMut` means that
`&mut T` can be viewed as `&mut T::Repr` and thus it needs to support
bi-directional transmutability.

To avoid duplicating implementations, all repr types are normalized to
unsigned integers.

Signed-off-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Tested-by: Alexandre Courbot <acourbot@nvidia.com>
Acked-by: Miguel Ojeda <ojeda@kernel.org>
Link: https://patch.msgid.link/20260901-typed_register-v4-3-5552b1d59525@garyguo.net
[ Fix grammar in from_repr_unchecked() documentation, rephrase confusing
  safety comment, use rustdoc links for Self, fix backtick formatting in
  comments and use consistent 'must' wording in safety sections.
  - Danilo ]
Signed-off-by: Danilo Krummrich <dakr@kernel.org>

0 files changed, 0 insertions, 0 deletions