iommu/omap: Check for valid archdata in attach_dev

Any device requiring to be attached to an iommu_domain must have
valid archdata containing the necessary iommu information, which
is SoC-specific. Add a check in the omap_iommu_attach_dev to make
sure that the device has valid archdata before accessing
different SoC-specific fields of the archdata. This prevents a
NULL pointer dereference on any misconfigured devices.

Signed-off-by: Suman Anna <s-anna@ti.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

drivers/iommu/omap-iommu.c

@@ -1091,6 +1091,11 @@ omap_iommu_attach_dev(struct iommu_domain *domain, struct device *dev)
 	struct omap_iommu_arch_data *arch_data = dev->archdata.iommu;
 	int ret = 0;
 
+	if (!arch_data || !arch_data->name) {
+		dev_err(dev, "device doesn't have an associated iommu\n");
+		return -EINVAL;
+	}
+
 	spin_lock(&omap_domain->lock);
 
 	/* only a single device is supported per domain for now */