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-rw-r--r--include/linux/dma-mapping.h7
1 files changed, 7 insertions, 0 deletions
diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index 2dc21cb..0ebfafb 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -24,6 +24,8 @@ enum dma_data_direction {
#define DMA_28BIT_MASK 0x000000000fffffffULL
#define DMA_24BIT_MASK 0x0000000000ffffffULL
+#define DMA_MASK_NONE 0x0ULL
+
static inline int valid_dma_direction(int dma_direction)
{
return ((dma_direction == DMA_BIDIRECTIONAL) ||
@@ -31,6 +33,11 @@ static inline int valid_dma_direction(int dma_direction)
(dma_direction == DMA_FROM_DEVICE));
}
+static inline int is_device_dma_capable(struct device *dev)
+{
+ return dev->dma_mask != NULL && *dev->dma_mask != DMA_MASK_NONE;
+}
+
#ifdef CONFIG_HAS_DMA
#include <asm/dma-mapping.h>
#else