gpu: host1x: Add IOMMU support

Add support for the Host1x unit to be located behind
an IOMMU. This is required when gather buffers may be
allocated non-contiguously in physical memory, as can
be the case when TegraDRM is also using the IOMMU.

Signed-off-by: Mikko Perttunen <mperttunen@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

drivers/gpu/host1x/dev.h

@@ -19,6 +19,8 @@
 
 #include <linux/platform_device.h>
 #include <linux/device.h>
+#include <linux/iommu.h>
+#include <linux/iova.h>
 
 #include "channel.h"
 #include "syncpt.h"
@@ -108,6 +110,10 @@ struct host1x {
 	struct device *dev;
 	struct clk *clk;
 
+	struct iommu_domain *domain;
+	struct iova_domain iova;
+	dma_addr_t iova_end;
+
 	struct mutex intr_mutex;
 	int intr_syncpt_irq;