Messages in this thread | | | Date | Tue, 3 May 2011 09:52:20 +0100 | From | Russell King - ARM Linux <> | Subject | Re: [RFC PATCH 4/4] ARM: Xilinx: Adding Xilinx board support |
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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: > > 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.
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