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

[Danilo Krummrich]

On Thu Feb 5, 2026 at 3:28 PM CET, Daniel Almeida wrote:
>
>
>> On 4 Feb 2026, at 12:18, Danilo Krummrich <dakr at 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 at 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.

Yes, little-endian should absolutely be the default. Please don't take the above
as specific suggestion. :)

>> 
>> 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
>>