ARM: IOMMU: Tegra20: Add iommu_ops for GART driver

Tegra 20 IOMMU H/W, GART (Graphics Address Relocation Table). This
patch implements struct iommu_ops for GART for the upper IOMMU API.

This H/W module supports only single virtual address space(domain),
and manages a single level 1-to-1 mapping H/W translation page table.

[With small fixes by Joerg Roedel]

Signed-off-by: Hiroshi DOYU <hdoyu@nvidia.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
index 6bea696..76c86da 100644
--- a/drivers/iommu/Kconfig
+++ b/drivers/iommu/Kconfig
@@ -142,4 +142,14 @@
 
          Say N unless you know you need this.
 
+config TEGRA_IOMMU_GART
+	bool "Tegra GART IOMMU Support"
+	depends on ARCH_TEGRA_2x_SOC
+	select IOMMU_API
+	help
+	  Enables support for remapping discontiguous physical memory
+	  shared with the operating system into contiguous I/O virtual
+	  space through the GART (Graphics Address Relocation Table)
+	  hardware included on Tegra SoCs.
+
 endif # IOMMU_SUPPORT