1. 根目录:
2. include
3. linux
4. swiotlb.h

#ifndef __LINUX_SWIOTLB_H
#define __LINUX_SWIOTLB_H

#include <linux/types.h>

struct device;
struct dma_attrs;
struct scatterlist;

extern int swiotlb_force;

/*
 * Maximum allowable number of contiguous slabs to map,
 * must be a power of 2.  What is the appropriate value ?
 * The complexity of {map,unmap}_single is linearly dependent on this value.
 */
#define IO_TLB_SEGSIZE	128

/*
 * log of the size of each IO TLB slab.  The number of slabs is command line
 * controllable.
 */
#define IO_TLB_SHIFT 11

extern void swiotlb_init(int verbose);
int swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose);
extern unsigned long swiotlb_nr_tbl(void);
unsigned long swiotlb_size_or_default(void);
extern int swiotlb_late_init_with_tbl(char *tlb, unsigned long nslabs);

/*
 * Enumeration for sync targets
 */
enum dma_sync_target {
	SYNC_FOR_CPU = 0,
	SYNC_FOR_DEVICE = 1,
};

/* define the last possible byte of physical address space as a mapping error */
#define SWIOTLB_MAP_ERROR (~(phys_addr_t)0x0)

extern phys_addr_t swiotlb_tbl_map_single(struct device *hwdev,
					  dma_addr_t tbl_dma_addr,
					  phys_addr_t phys, size_t size,
					  enum dma_data_direction dir);

extern void swiotlb_tbl_unmap_single(struct device *hwdev,
				     phys_addr_t tlb_addr,
				     size_t size, enum dma_data_direction dir);

extern void swiotlb_tbl_sync_single(struct device *hwdev,
				    phys_addr_t tlb_addr,
				    size_t size, enum dma_data_direction dir,
				    enum dma_sync_target target);

/* Accessory functions. */
extern void
*swiotlb_alloc_coherent(struct device *hwdev, size_t size,
			dma_addr_t *dma_handle, gfp_t flags);

extern void
swiotlb_free_coherent(struct device *hwdev, size_t size,
		      void *vaddr, dma_addr_t dma_handle);

extern dma_addr_t swiotlb_map_page(struct device *dev, struct page *page,
				   unsigned long offset, size_t size,
				   enum dma_data_direction dir,
				   struct dma_attrs *attrs);
extern void swiotlb_unmap_page(struct device *hwdev, dma_addr_t dev_addr,
			       size_t size, enum dma_data_direction dir,
			       struct dma_attrs *attrs);

extern int
swiotlb_map_sg(struct device *hwdev, struct scatterlist *sg, int nents,
	       enum dma_data_direction dir);

extern void
swiotlb_unmap_sg(struct device *hwdev, struct scatterlist *sg, int nents,
		 enum dma_data_direction dir);

extern int
swiotlb_map_sg_attrs(struct device *hwdev, struct scatterlist *sgl, int nelems,
		     enum dma_data_direction dir, struct dma_attrs *attrs);

extern void
swiotlb_unmap_sg_attrs(struct device *hwdev, struct scatterlist *sgl,
		       int nelems, enum dma_data_direction dir,
		       struct dma_attrs *attrs);

extern void
swiotlb_sync_single_for_cpu(struct device *hwdev, dma_addr_t dev_addr,
			    size_t size, enum dma_data_direction dir);

extern void
swiotlb_sync_sg_for_cpu(struct device *hwdev, struct scatterlist *sg,
			int nelems, enum dma_data_direction dir);

extern void
swiotlb_sync_single_for_device(struct device *hwdev, dma_addr_t dev_addr,
			       size_t size, enum dma_data_direction dir);

extern void
swiotlb_sync_sg_for_device(struct device *hwdev, struct scatterlist *sg,
			   int nelems, enum dma_data_direction dir);

extern int
swiotlb_dma_mapping_error(struct device *hwdev, dma_addr_t dma_addr);

extern int
swiotlb_dma_supported(struct device *hwdev, u64 mask);

#ifdef CONFIG_SWIOTLB
extern void __init swiotlb_free(void);
#else
static inline void swiotlb_free(void) { }
#endif

extern void swiotlb_print_info(void);
extern int is_swiotlb_buffer(phys_addr_t paddr);

#endif /* __LINUX_SWIOTLB_H */