powerpc/iommu: Remove dma_data union

To support "hybrid" DMA ops in a subsequent patch, we will need both
a direct DMA offset and an iommu pointer. Those are currently exclusive
(a union), so change them to be separate fields.

While there, also type iommu_table_base properly and make exist only
on CONFIG_PPC64 since it's not referenced on 32-bit at all.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

1 files changed, 9 insertions, 6 deletions

diff --git a/arch/powerpc/include/asm/device.h b/arch/powerpc/include/asm/device.h
index e9bdda88f1fb..406c2b1ff82d 100644
--- a/arch/powerpc/include/asm/device.h
+++ b/arch/powerpc/include/asm/device.h
@@ -10,6 +10,7 @@ struct dma_map_ops;
 struct device_node;
 #ifdef CONFIG_PPC64
 struct pci_dn;
+struct iommu_table;
 #endif
 
 /*
@@ -23,13 +24,15 @@ struct dev_archdata {
 	struct dma_map_ops	*dma_ops;
 
 	/*
-	 * 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.
+	 * These two used to be a union. However, with the hybrid ops we need
+	 * both so here we store both a DMA offset for direct mappings and
+	 * an iommu_table for remapped DMA.
 	 */
-	union {
-		dma_addr_t	dma_offset;
-		void		*iommu_table_base;
-	} dma_data;
+	dma_addr_t		dma_offset;
+
+#ifdef CONFIG_PPC64
+	struct iommu_table	*iommu_table_base;
+#endif
 
 #ifdef CONFIG_IOMMU_API
 	void			*iommu_domain;