[PATCH] Use Normal uncached memory rather than Strongly Ordered on ARMv6+

[David Brown]

On Fri, Oct 23, 2009 at 05:36:00AM -0700, Russell King - ARM Linux wrote:

> > Alternatively, we can place a DMB in readl/writel but I'm not sure about
> > the performance impact.
> 
> If you do that, you might as well use strongly ordered memory for device
> mappings - since you'll be causing the CPU to stall after each access.

Actually, the DMB is stronger than strongly ordered.  Strongly
ordered only guarantees ordering within somewhat arbitrarily
defined (and not completely settled) 1KB boundaries, for memory
mapped peripherals.

David