RFC on writel and writel_relaxed

[Benjamin Herrenschmidt]

On Wed, 2018-03-28 at 09:53 +0100, Will Deacon wrote:
> For arm/arm64 these end up behaving exactly the same as readX/writeX, but
> I'm nervous about changing the documentation without understanding why it's
> like it is currently. Maybe another ia64 thing?.

I doubt it ... the Intel ancestry here would make me think they are
completely ordered there too.

powerpc and ARM can't quite make them synchronous I think, but at least
they should have the same semantics as writel.

Cheers,
Ben.