1. 根目录:
2. arch
3. alpha
4. include
5. asm
6. dma-mapping.h

#ifndef _ALPHA_DMA_MAPPING_H
#define _ALPHA_DMA_MAPPING_H

#include <linux/dma-attrs.h>

extern struct dma_map_ops *dma_ops;

static inline struct dma_map_ops *get_dma_ops(struct device *dev)
{
	return dma_ops;
}

#include <asm-generic/dma-mapping-common.h>

#define dma_cache_sync(dev, va, size, dir)		  ((void)0)

#endif	/* _ALPHA_DMA_MAPPING_H */