iommu/omap: Play nice in multi-platform builds

The OMAP IOMMU driver unconditionally executes code and registers a
struct iommu_ops with the platform bus irrespective of whether it runs
on an OMAP SoC or not. This causes problems in multi-platform kernels
where drivers for other SoCs will no longer be able to register their
own struct iommu_ops or even try to use a struct iommu_ops for an IOMMU
that obviously isn't there.

The smallest fix I could think of is to check for the existence of any
OMAP IOMMU devices in the device tree and skip initialization otherwise.

This fixes a problem on Tegra20 where the DRM driver will try to use the
obviously non-existent OMAP IOMMU.

Reported-by: Nicolas Chauvet <[email protected]>
Cc: Tony Lindgren <[email protected]>
Cc: Suman Anna <[email protected]>
Cc: Laurent Pinchart <[email protected]>
Signed-off-by: Thierry Reding <[email protected]>
Acked-by: Laurent Pinchart <[email protected]>
Signed-off-by: Joerg Roedel <[email protected]>

0 files changed, 0 insertions, 0 deletions