diff --git a/arch/powerpc/include/asm/iommu.h b/arch/powerpc/include/asm/iommu.h
index e94a5e3c5a2f..d91bd69d3196 100644
--- a/arch/powerpc/include/asm/iommu.h
+++ b/arch/powerpc/include/asm/iommu.h
@@ -200,6 +200,7 @@ extern int iommu_take_ownership(struct iommu_table *tbl);
 extern void iommu_release_ownership(struct iommu_table *tbl);
 
 extern enum dma_data_direction iommu_tce_direction(unsigned long tce);
+extern unsigned long iommu_direction_to_tce_perm(enum dma_data_direction dir);
 
 #endif /* __KERNEL__ */
 #endif /* _ASM_IOMMU_H */
diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c
index 0019c80aa81d..ac2f959adf9a 100644
--- a/arch/powerpc/kernel/iommu.c
+++ b/arch/powerpc/kernel/iommu.c
@@ -866,6 +866,21 @@ void iommu_free_coherent(struct iommu_table *tbl, size_t size,
 	}
 }
 
+unsigned long iommu_direction_to_tce_perm(enum dma_data_direction dir)
+{
+	switch (dir) {
+	case DMA_BIDIRECTIONAL:
+		return TCE_PCI_READ | TCE_PCI_WRITE;
+	case DMA_FROM_DEVICE:
+		return TCE_PCI_WRITE;
+	case DMA_TO_DEVICE:
+		return TCE_PCI_READ;
+	default:
+		return 0;
+	}
+}
+EXPORT_SYMBOL_GPL(iommu_direction_to_tce_perm);
+
 #ifdef CONFIG_IOMMU_API
 /*
  * SPAPR TCE API
diff --git a/arch/powerpc/platforms/powernv/pci.c b/arch/powerpc/platforms/powernv/pci.c
index 3c35487e9778..1477422b907a 100644
--- a/arch/powerpc/platforms/powernv/pci.c
+++ b/arch/powerpc/platforms/powernv/pci.c
@@ -576,15 +576,10 @@ static int pnv_tce_build(struct iommu_table *tbl, long index, long npages,
 			 unsigned long uaddr, enum dma_data_direction direction,
 			 struct dma_attrs *attrs, bool rm)
 {
-	u64 proto_tce;
+	u64 proto_tce = iommu_direction_to_tce_perm(direction);
 	__be64 *tcep, *tces;
 	u64 rpn;
 
-	proto_tce = TCE_PCI_READ; // Read allowed
-
-	if (direction != DMA_TO_DEVICE)
-		proto_tce |= TCE_PCI_WRITE;
-
 	tces = tcep = ((__be64 *)tbl->it_base) + index - tbl->it_offset;
 	rpn = __pa(uaddr) >> tbl->it_page_shift;