Re: [PATCH 1/1] arm/dts: Tegra30: Add device tree support for SMMU

[Stephen Warren <swarren-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org>]

On 04/16/2012 04:10 AM, Hiroshi Doyu wrote:
> Stephen Warren wrote at Fri, 13 Apr 2012 21:33:47 +0200:
>> On 04/13/2012 04:22 AM, Hiroshi Doyu wrote:
>>> Add device tree support for Tegra30 IOMMU(SMMU).
...
>> But why does the SMMU driver expect to control the AHB arbitration
>> registers? They seem unrelated to the SMMU.
> 
> It's necessary to inform AHB that SMMU is ready to use. There's a
> dedicated bit for SMMU in this AHB arbitration register.

Shouldn't there be a dedicated driver for the AHB arbitration registers
that the SMMU driver calls into to achieve this? IIRC, the AHB
arbitration registers support much more than the SMMU enable, and if we
ever need to touch those other features, going to the SMMU driver to do
so probably wouldn't make sense.