ARM: OMAP: iommu: declare a private iommu binding struct

Declare an omap iommu private struct, which binds an iommu user
to its iommu device. This struct should be placed at the iommu user's
dev_archdata so generic IOMMU API can be used without having to
utilize omap-specific plumbing anymore.

While at it, provide an accessor method to ease the retrieval of the
omap_iommu handle from a user device.

Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Cc: Hiroshi Doyu <hdoyu@nvidia.com>

arch/arm/plat-omap/include/plat/iommu.h

@@ -111,6 +111,32 @@ struct iommu_platform_data {
 	u32 da_end;
 };
 
+/**
+ * struct iommu_arch_data - omap iommu private data
+ * @name: name of the iommu device
+ * @iommu_dev: handle of the iommu device
+ *
+ * This is an omap iommu private data object, which binds an iommu user
+ * to its iommu device. This object should be placed at the iommu user's
+ * dev_archdata so generic IOMMU API can be used without having to
+ * utilize omap-specific plumbing anymore.
+ */
+struct omap_iommu_arch_data {
+	const char *name;
+	struct omap_iommu *iommu_dev;
+};
+
+/**
+ * dev_to_omap_iommu() - retrieves an omap iommu object from a user device
+ * @dev: iommu client device
+ */
+static inline struct omap_iommu *dev_to_omap_iommu(struct device *dev)
+{
+	struct omap_iommu_arch_data *arch_data = dev->archdata.iommu;
+
+	return arch_data->iommu_dev;
+}
+
 /* IOMMU errors */
 #define OMAP_IOMMU_ERR_TLB_MISS		(1 << 0)
 #define OMAP_IOMMU_ERR_TRANS_FAULT	(1 << 1)