2 files changed, 52 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/dma-iommu.c b/arch/powerpc/kernel/dma-iommu.c
index e7554154a6d..1f2a711a261 100644
--- a/arch/powerpc/kernel/dma-iommu.c
+++ b/arch/powerpc/kernel/dma-iommu.c
@@ -90,6 +90,19 @@ static int dma_iommu_dma_supported(struct device *dev, u64 mask)
 		return 1;
 }
 
+u64 dma_iommu_get_required_mask(struct device *dev)
+{
+	struct iommu_table *tbl = get_iommu_table_base(dev);
+	u64 mask;
+	if (!tbl)
+		return 0;
+
+	mask = 1ULL < (fls_long(tbl->it_offset + tbl->it_size) - 1);
+	mask += mask - 1;
+
+	return mask;
+}
+
 struct dma_map_ops dma_iommu_ops = {
 	.alloc_coherent	= dma_iommu_alloc_coherent,
 	.free_coherent	= dma_iommu_free_coherent,
diff --git a/arch/powerpc/kernel/dma.c b/arch/powerpc/kernel/dma.c
index 4f0959fbfbe..503093efa20 100644
--- a/arch/powerpc/kernel/dma.c
+++ b/arch/powerpc/kernel/dma.c
@@ -170,6 +170,45 @@ int dma_set_mask(struct device *dev, u64 dma_mask)
 }
 EXPORT_SYMBOL(dma_set_mask);
 
+u64 dma_get_required_mask(struct device *dev)
+{
+	struct dma_map_ops *dma_ops = get_dma_ops(dev);
+	u64 mask, end = 0;
+
+	if (ppc_md.dma_get_required_mask)
+		return ppc_md.dma_get_required_mask(dev);
+
+	if (unlikely(dma_ops == NULL))
+		return 0;
+
+#ifdef CONFIG_PPC64
+	else if (dma_ops == &dma_iommu_ops)
+		return dma_iommu_get_required_mask(dev);
+#endif
+#ifdef CONFIG_SWIOTLB
+	else if (dma_ops == &swiotlb_dma_ops) {
+		u64 max_direct_dma_addr = dev->archdata.max_direct_dma_addr;
+
+		end = memblock_end_of_DRAM();
+		if (max_direct_dma_addr && end > max_direct_dma_addr)
+			end = max_direct_dma_addr;
+		end += get_dma_offset(dev);
+	}
+#endif
+	else if (dma_ops == &dma_direct_ops)
+		end = memblock_end_of_DRAM() + get_dma_offset(dev);
+	else {
+		WARN_ONCE(1, "%s: unknown ops %p\n", __func__, dma_ops);
+		end = memblock_end_of_DRAM();
+	}
+
+	mask = 1ULL << (fls64(end) - 1);
+	mask += mask - 1;
+
+	return mask;
+}
+EXPORT_SYMBOL_GPL(dma_get_required_mask);
+
 static int __init dma_init(void)
 {
        dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES);