Re: [PATCH v2] rust: io: Add a BigEndianMmio wrapper

[Link Mauve]

On Thu, Aug 06, 2026 at 12:44:31PM +0100, Gary Guo wrote:
> On Thu Aug 6, 2026 at 7:22 AM BST, Link Mauve wrote:
> > This allows the user to read from and write to big-endian MMIO devices,
> > such as those found on PowerPC systems.
> >
> > The implementation is pretty much a copy-paste of the RelaxedMmio type,
> > with the business logic changed.
> >
> > This has been tested with various WIP drivers on the Nintendo Wii, and I
> > thought it would be nicer to upstream it before those are completely
> > ready, to get some review.
> 
> An alternative approach would be to have a generic wrapper `BigEndian<IO>` where
> it performs byte-swapping in its `IoCapable` implementation. This is more
> composable as it works for all I/O.
> 
> Of course, this means that it won't be using the specialized BE I/O impl, but
> then the only architectures that have specialized ioread16be are PPC32 and
> SPARC, so maybe it's a reasonable trade-off to make?

In the end this should all be inlined anyway, I’ll compare the generated
assembly but I expect no change here.

> 
> Best,
> Gary
[…]

-- 
Link Mauve