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>

1 files changed, 10 insertions, 1 deletions

diff --git a/arch/powerpc/include/asm/device.h b/arch/powerpc/include/asm/device.h
index 9dade15d1ab4..6d94d27ed850 100644
--- a/arch/powerpc/include/asm/device.h
+++ b/arch/powerpc/include/asm/device.h
@@ -15,7 +15,16 @@ struct dev_archdata {
 
         /* DMA operations on that device */
         struct dma_map_ops      *dma_ops;
-        void                    *dma_data;
+
+        /*
+         * When an iommu is in use, dma_data is used as a ptr to the base of the
+         * iommu_table.  Otherwise, it is a simple numerical offset.
+         */
+        union {
+                dma_addr_t      dma_offset;
+                void            *iommu_table_base;
+        } dma_data;
+
 #ifdef CONFIG_SWIOTLB
         dma_addr_t              max_direct_dma_addr;
 #endif