1. 根目录:
2. arch
3. s390
4. include
5. asm
6. dma-mapping.h

#ifndef _ASM_S390_DMA_MAPPING_H
#define _ASM_S390_DMA_MAPPING_H

#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/mm.h>
#include <linux/scatterlist.h>
#include <linux/dma-attrs.h>
#include <linux/dma-debug.h>
#include <linux/io.h>

#define DMA_ERROR_CODE		(~(dma_addr_t) 0x0)

extern struct dma_map_ops s390_dma_ops;

static inline struct dma_map_ops *get_dma_ops(struct device *dev)
{
	return &s390_dma_ops;
}

static inline void dma_cache_sync(struct device *dev, void *vaddr, size_t size,
				  enum dma_data_direction direction)
{
}

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

static inline bool dma_capable(struct device *dev, dma_addr_t addr, size_t size)
{
	if (!dev->dma_mask)
		return false;
	return addr + size - 1 <= *dev->dma_mask;
}

#endif /* _ASM_S390_DMA_MAPPING_H */