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

#ifndef ASMARM_DMA_IOMMU_H
#define ASMARM_DMA_IOMMU_H

#ifdef __KERNEL__

#include <linux/mm_types.h>
#include <linux/scatterlist.h>
#include <linux/dma-debug.h>
#include <linux/kmemcheck.h>
#include <linux/kref.h>

struct dma_iommu_mapping {
	/* iommu specific data */
	struct iommu_domain	*domain;

	void			*bitmap;
	size_t			bits;
	unsigned int		order;
	dma_addr_t		base;

	spinlock_t		lock;
	struct kref		kref;
};

struct dma_iommu_mapping *
arm_iommu_create_mapping(struct bus_type *bus, dma_addr_t base, size_t size,
			 int order);

void arm_iommu_release_mapping(struct dma_iommu_mapping *mapping);

int arm_iommu_attach_device(struct device *dev,
					struct dma_iommu_mapping *mapping);
void arm_iommu_detach_device(struct device *dev);

#endif /* __KERNEL__ */
#endif