That's true. However, the point is that include/iommu.h is far from
the IOMMU-API.
You could still insist that include/iommu.h is designed for the
generic IOMMU-API. But the fact is that it's designed for very
specific purposes. No intention to make it for generic purposes.
Since you added it two years ago, nobody has tried to extend
it. Instead, we have something like
arch/arm/plat-omap/include/plat/iommu.h.
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