[RFC PATCH 4/4] ARM: Xilinx: Adding Xilinx board support

On Tue, May 03, 2011 at 09:58:14AM +0200, Arnd Bergmann wrote:

On Tuesday 03 May 2011 01:01:18 Russell King - ARM Linux wrote:

quoted

It is preferable to use the same mapping, as it ensures that you're not
going to create incompatible aliases.

Is aliasing a problem for MMIO mappings? I would think that you can
ioremap registers anywhere and as often as you want because they are
never cacheable.

Provided the type and sharability is identical then there is no problem.
I wasn't referring to multiple ioremap()s of the same region - that
should be fine as the same attributes will be used.  If you mix ioremap()
and iotable_init() then you _could_ have problems if you don't use
MT_DEVICE in the iotable.

What I'm basically saying is that mixing the methods of creating these
mappings makes it much easier to get tripped up over these issues.