Re: [PATCH] MIPS: Introduce aligned IO memory operations

[Thomas Bogendoerfer <tsbogend@alpha.franken.de>]

On Wed, Jan 22, 2020 at 10:45:06AM -0800, Paul Burton wrote:
> Hi Jiaxun,
> 
> On Tue, Jan 14, 2020 at 08:23:43PM +0800, Jiaxun Yang wrote:
> > Some platforms, such as Loongson64 or QEMU/KVM, don't support unaligned
> > instructions like lwl or lwr in IO memory access. However, our current
> > IO memcpy/memset is wired to the generic implementation, which leads
> > to a fatal result.
> 
> Hmm, I wonder if we should just do this unconditionally on all systems.
> I can't think of a reason it'd ever be a good idea to use lwl/lwr on an
> MMIO device. Any thoughts on that?

depends on the type of device. I can see benefits for framebuffers
and memory devices since memset/memcpy are more optimised than the
function in this patch.

Thomas.

-- 
Crap can work. Given enough thrust pigs will fly, but it's not necessarily a
good idea.                                                [ RFC1925, 2.3 ]