Re: [PATCH RESEND v4 4/4] sample: rust: pci: add tests for config space routines

[Danilo Krummrich <dakr@kernel.org>]

On 11/4/25 5:42 PM, Zhi Wang wrote:
> Should I arrange the traits like below?
> 
> Io trait - Main trait + 32-bit access
>  | 
>  | -- Common address/bound checks
>  |
>  |	(accessor traits)
>  | -- Io Fallible trait - (MMIO backend implements)
>  | -- Io Infallible trait - (MMIO/ConfigSpace backend implements this)
>  |
>  | -- Io64 trait - For backend supports 64 bit access
> 	   |      (accessor traits)
>            | -- Io64 Faillable trait (MMIO backend implements this)
> 	   | -- Io64 Infallible trait (MMIO backend implements this)
> 
> I am also thinking if we should keep 64-bit access accessor in the
> backend implementation instead in the Io trait (like {read, write}
> _relaxed), because I think few backend (PCI Config Space/I2C/SPI) would
> support 64-bit atomic access except MMIO backend.

SGTM, I think it's fine to keep 64-bit in the MMIO backend for now, we can
always split it out into a separate trait once needed.