[PATCH v2 03/22] ARM: tegra: Create a DT header defining swgroups ID

[Hiroshi Doyu]

On Mon, 29 Jul 2013 19:45:15 +0200
Stephen Warren <swarren at wwwdotorg.org> wrote:

> On 07/29/2013 04:53 AM, Hiroshi Doyu wrote:
> > Stephen Warren <swarren at wwwdotorg.org> wrote @ Wed, 17 Jul 2013 01:07:12 +0200:
> > 
> >> On 07/05/2013 04:44 AM, Hiroshi Doyu wrote:
> >>> Create a header file to define the swgroup IDs used by the IOMMU(SMMU)
> >>> binding. "swgroup" is a group of H/W clients in Tegra SoC from S/W POV.
> >>>
> >>> This will allow the same header to be used by both device tree files,
> >>> and drivers implementing this binding, which guarantees that the two
> >>> stay in sync. This also makes device trees more readable by using names
> >>> instead of magic numbers.
> >>
> >> Why does the driver need these constants; shouldn't it simply support
> >> 0..n SW group IDs that all work the same way? Or, is there some reason
> >> for it to know the identities?
> >>
> >>> diff --git a/include/dt-bindings/memory/tegra-swgroup.h b/include/dt-bindings/memory/tegra-swgroup.h
> >>
> >> s/memory/iommu/?
> > 
> > This info would be used in PMC code as well, which H/W belongs to
> > which swgroup. So I use the term "memory(-client)" instead of "iommu".
> 
> Why does the PMC care? An explanation of exactly what SW needs to know
> about these groups and why would be a good idea.

Joseph, can you explain a bit here?