Re: [PATCH v4] devicetree: Add generic IOMMU device tree bindings

Will Deacon
2014-07-09T13:44:32Z

On Fri, Jul 04, 2014 at 04:29:17PM +0100, Thierry Reding wrote:
> From: Thierry Reding <treding@nvidia.com>
>
> This commit introduces a generic device tree binding for IOMMU devices.
> Only a very minimal subset is described here, but it is enough to cover
> the requirements of both the Exynos System MMU and Tegra SMMU as
> discussed here:
>
> https://lkml.org/lkml/2014/4/27/346
>
> Signed-off-by: Thierry Reding <treding@nvidia.com>

Acked-by: Will Deacon <will.deacon@arm.com>

I would like to move the ARM SMMU driver over to this for 3.18, if possible.
One use-case there is the ability to describe groups of masters behind a
multi-master IOMMU but which must be part of the same domain (i.e. an
iommu_group). This is useful for presenting devices to a guest with a
virtual SMMU, where the physical devices share a stage-2 context.

With your binding, does this simply mean determining the set of master IDs
in the group, then describing the complete set for each master?

Will