powerpc: Change archdata dma_data to a union

Sometimes this is used to hold a simple offset, and sometimes
it is used to hold a pointer.  This patch changes it to a union containing
void * and dma_addr_t.  get/set accessors are also provided, because it was
getting a bit ugly to get to the actual data.

Signed-off-by: Becky Bruce <beckyb@kernel.crashing.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/arch/powerpc/kernel/dma-iommu.c b/arch/powerpc/kernel/dma-iommu.c
index 87ddb3f..37771a5 100644
--- a/arch/powerpc/kernel/dma-iommu.c
+++ b/arch/powerpc/kernel/dma-iommu.c
@@ -18,7 +18,7 @@
 static void *dma_iommu_alloc_coherent(struct device *dev, size_t size,
 				      dma_addr_t *dma_handle, gfp_t flag)
 {
-	return iommu_alloc_coherent(dev, dev->archdata.dma_data, size,
+	return iommu_alloc_coherent(dev, get_iommu_table_base(dev), size,
 				    dma_handle, device_to_mask(dev), flag,
 				    dev_to_node(dev));
 }
@@ -26,7 +26,7 @@
 static void dma_iommu_free_coherent(struct device *dev, size_t size,
 				    void *vaddr, dma_addr_t dma_handle)
 {
-	iommu_free_coherent(dev->archdata.dma_data, size, vaddr, dma_handle);
+	iommu_free_coherent(get_iommu_table_base(dev), size, vaddr, dma_handle);
 }
 
 /* Creates TCEs for a user provided buffer.  The user buffer must be
@@ -39,8 +39,8 @@
 				     enum dma_data_direction direction,
 				     struct dma_attrs *attrs)
 {
-	return iommu_map_page(dev, dev->archdata.dma_data, page, offset, size,
-			      device_to_mask(dev), direction, attrs);
+	return iommu_map_page(dev, get_iommu_table_base(dev), page, offset,
+			      size, device_to_mask(dev), direction, attrs);
 }
 
 
@@ -48,7 +48,7 @@
 				 size_t size, enum dma_data_direction direction,
 				 struct dma_attrs *attrs)
 {
-	iommu_unmap_page(dev->archdata.dma_data, dma_handle, size, direction,
+	iommu_unmap_page(get_iommu_table_base(dev), dma_handle, size, direction,
 			 attrs);
 }
 
@@ -57,7 +57,7 @@
 			    int nelems, enum dma_data_direction direction,
 			    struct dma_attrs *attrs)
 {
-	return iommu_map_sg(dev, dev->archdata.dma_data, sglist, nelems,
+	return iommu_map_sg(dev, get_iommu_table_base(dev), sglist, nelems,
 			    device_to_mask(dev), direction, attrs);
 }
 
@@ -65,14 +65,14 @@
 		int nelems, enum dma_data_direction direction,
 		struct dma_attrs *attrs)
 {
-	iommu_unmap_sg(dev->archdata.dma_data, sglist, nelems, direction,
+	iommu_unmap_sg(get_iommu_table_base(dev), sglist, nelems, direction,
 		       attrs);
 }
 
 /* We support DMA to/from any memory page via the iommu */
 static int dma_iommu_dma_supported(struct device *dev, u64 mask)
 {
-	struct iommu_table *tbl = dev->archdata.dma_data;
+	struct iommu_table *tbl = get_iommu_table_base(dev);
 
 	if (!tbl || tbl->it_offset > mask) {
 		printk(KERN_INFO