Re: [PATCH] fb.h: ARM uses __raw_{read/write}
From: Arnd Bergmann
Date: Mon Jun 13 2011 - 09:37:37 EST
On Monday 13 June 2011 12:08:19 Catalin Marinas wrote:
> The change proposed by Hartley wouldn't make much difference from the
> current volatile accesses (__raw_* accessors are implemented as volatile
> on ARM).
I guess it would mainly make a difference if we get a platform where
the PCI bus window is not in the same address space as the regular
physical memory and the accessors actually need to do a computation
on the address. AFAICT, ARM does not currently have any such platform
and I would hope that it says that way.
> I think the memcpy_(from|to)io could be optimised on ARM to only add a
> barrier before or after he copying loop.
Agreed, good idea.
Arnd
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