Re: [PATCH] parisc: Remove memcpy_fromio

[Arnd Bergmann]

On Thu, Jan 30, 2025, at 14:48, Julian Vetter wrote:
> Fully migrate parisc to the IO functions from lib/iomem_copy.c. In a
> recent patch the functions memset_io and memcpy_toio were removed, but
> the memcpy_fromio was kept, because for very short sequences it does
> half word accesses, whereas the functions in lib/iomem_copy.c do byte
> accesses until the memory is naturally aligned and then do machine word
> accesses. But I don't think the single half-word access merits keeping
> the arch specific implementation, so, remove it as well.
>
> Signed-off-by: Julian Vetter <julian@xxxxxxxxxxxxxxxx>

Acked-by: Arnd Bergmann <arnd@xxxxxxxx>

This one looks fairly obvious. It might be nice to also
clean up the {in,out}s{b,w,l} helper functions in the same
file, but I don't understand why those are special
in the first place.

Those functions have been unchanged since before the git
history and there are some comments that I don't find helpful.
One thing they do is to deal with unaligned memory buffers,
which the generic ones don't, but that could be easily added
using get_unaligned/put_unaligned, expecting the compiler
to optimize the memory side of the transfer.

     Arnd