Re: [PATCH v10 2/5] rust: io: separate generic I/O helpers from MMIO implementation

[Gary Guo]

On Tue Jan 20, 2026 at 10:12 AM GMT, Danilo Krummrich wrote:
> On Tue Jan 20, 2026 at 9:04 AM CET, Alice Ryhl wrote:
>> On Mon, Jan 19, 2026 at 10:22:44PM +0200, Zhi Wang wrote:
>> Overall looks good to me. Some comments below:
>>
>> I still think it would make sense to have `IoCapable<T>: IoTryCapable<T>`,
>> but it's not a big deal.

Ah, I sent out my review without realizing that Alice is purposing the same.

>
> I think with this approach it's not necessary to have this requirement. In
> practice, most impls will have both, but I think it's a good thing that we don't
> have to have an impl even if not used by any driver, i.e. it helps avoiding dead
> code.

I think whether there's a runtime bound checking and whether a IO size is
supported are two orthogonal things, I would rather we have a single series of
`IoCapable<T>` to just indiate the latter and still keep the `IoKnownSize`.

Best,
Gary


>
>>> +    /// Infallible 64-bit read with compile-time bounds check.
>>> +    #[cfg(CONFIG_64BIT)]
>>> +    fn read64(&self, offset: usize) -> u64
>>> +    #[cfg(CONFIG_64BIT)]
>>> +    fn try_read64(&self, offset: usize) -> Result<u64>
>>
>> These don't really need cfg(CONFIG_64BIT). You can place that cfg on
>> impl blocks of IoCapable<u64>.
>
> If you agree with the above, I can fix this up when applying the series.