Re: [PATCH v5 0/9] Introduce bitfield and move register macro to rust/kernel/

[Alexandre Courbot]

On Thu Oct 2, 2025 at 10:24 AM JST, Alexandre Courbot wrote:
> On Tue Sep 30, 2025 at 11:45 PM JST, Joel Fernandes wrote:
>> Hello!
>>
>> These patches extract and enhance the bitfield support in the register macro in
>> nova to define Rust structures with bitfields. It then moves out the bitfield
>> support into the kenrel crate and further enhances it. This is extremely useful
>> as it allows clean Rust structure definitions without requiring explicit masks
>> and shifts.
>
> The extraction and move in themselves (patches 1-4 and maybe the KUNIT
> one) look good to me. For the remainder, it will depend on whether the
> BoundedInt idea sticks or not as it changes the design in a way that
> makes most of these patches unneeded. In any case I think this can be
> worked on after the split and extraction.
>
> Patch 5 should probably be dropped as it has the potential to clear
> register fields that are useful to the hardware but have no entry in the
> `register!` definition, making read-update-write updates of registers
> unpredictable.

Ah, I forgot: please base the next revision on top of drm-rust-next as
we are likely to apply it there.