[RFC 06/18] arm: msm: implement proper dmb() for 7x27

[Russell King - ARM Linux]

On Mon, Jan 11, 2010 at 02:47:25PM -0800, Daniel Walker wrote:
> From: Larry Bassel <lbassel at quicinc.com>
> 
> For 7x27 it is necessary to write to strongly
> ordered memory after executing the coprocessor 15
> instruction dmb instruction.
> 
> This is only for data barrier dmb().
> Note that the test for 7x27 is done on all MSM platforms
> (even ones such as 7201a whose kernel is distinct from
> that of 7x25/7x27).
> 
> Acked-by: Willie Ruan <wruan at quicinc.com>
> Signed-off-by: Larry Bassel <lbassel at quicinc.com>
> Signed-off-by: Daniel Walker <dwalker at codeaurora.org>

Can only see half of this change - what's the actual implementation of
arch_barrier_extra()?

I'd prefer not to include asm/memory.h into asm/system.h to avoid
needlessly polluting headers.