iommu: add dma_get_mask helper function

Several IOMMUs do the same thing to get the dma_mask of a device. This
adds a helper function to do the same thing to sweep them.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index 6ed50c1642f1c10f587602e2864d233dc40428d5..0dba7433af1805d31991df2698e30d6a112bedec 100644 (file)
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -63,6 +63,13 @@ static inline int is_buffer_dma_capable(u64 mask, dma_addr_t addr, size_t size)
 #define dma_sync_single                dma_sync_single_for_cpu
 #define dma_sync_sg            dma_sync_sg_for_cpu
 
+static inline u64 dma_get_mask(struct device *dev)
+{
+       if (dev->dma_mask && *dev->dma_mask)
+               return *dev->dma_mask;
+       return DMA_32BIT_MASK;
+}
+
 extern u64 dma_get_required_mask(struct device *dev);
 
 static inline unsigned int dma_get_max_seg_size(struct device *dev)