omap: iommu: Gracefully fail iommu_enable if no arch_iommu is registered

In a modular build of the iommu code it's possible that the arch iommu code
isn't loaded when trying to enable the iommu. Instead of blindly following a
null pointer return -NODEV in that case.

Signed-off-by: Martin Hostettler <martin@neutronstar.dyndns.org>
Signed-off-by: Tony Lindgren <tony@atomide.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/arch/arm/plat-omap/iommu.c b/arch/arm/plat-omap/iommu.c
index b1107c08da56..3d8f55ea8666 100644
--- a/arch/arm/plat-omap/iommu.c
+++ b/arch/arm/plat-omap/iommu.c
@@ -104,6 +104,9 @@ static int iommu_enable(struct iommu *obj)
         if (!obj)
                 return -EINVAL;
 
+        if (!arch_iommu)
+                return -ENODEV;
+
         clk_enable(obj->clk);
 
         err = arch_iommu->enable(obj);