Re: [PATCH v2 1/4] rust: io: Add big-endian read and write functions

Daniel Almeida
2026-02-05T18:08:43Z

> On 4 Feb 2026, at 12:18, Danilo Krummrich <dakr@kernel.org> wrote:
>
> On Wed Feb 4, 2026 at 5:04 AM CET, Link Mauve wrote:
>> Another option would be to call u32::swap_bytes() on the data being
>> read/written, but these helpers make the Rust code as ergonomic as the C
>> code.
>>
>> Signed-off-by: Link Mauve <linkmauve@linkmauve.fr>
>
> The I/O stuff recently changed quite significantly, please have a look at the
> driver-core-next branch [1] in the driver-core tree.
>
> Also, instead of providing additional *be() methods, we should just create a new
> type io::Endianness and use it to indicate the device endianness when requesting
> the I/O resource.
>
> For instance, for your driver we could have
>
> request.iomap_exclusive_sized::<8>(Endianness::Big)?

Can we please structure this in a way that LittleEndian is the default?
Perhaps using a const generic that is defaulted, or something along these lines.

>
> and then let the I/O backend choose the correct accessors based on this.
>
> I.e. the device is either big or little endian, hence we don't need to provide
> both accessors at the same time.
>
> [1] https://git.kernel.org/pub/scm/linux/kernel/git/driver-core/driver-core.git/log/?h=driver-core-next
>