text: /* SPDX-License-Identifier: GPL-2.0 */
  #ifndef __LINUX_SWIOTLB_H
  #define __LINUX_SWIOTLB_H
  
  #include <linux/dma-direction.h>
  #include <linux/init.h>
  #include <linux/types.h>
  
  struct device;
  struct page;
  struct scatterlist;
  
  enum swiotlb_force {
  	SWIOTLB_NORMAL,		/* Default - depending on HW DMA mask etc. */
  	SWIOTLB_FORCE,		/* swiotlb=force */
  	SWIOTLB_NO_FORCE,	/* swiotlb=noforce */
  };
  
  /*
   * 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);
  extern void __init swiotlb_update_mem_attributes(void);
  
  /*
   * Enumeration for sync targets
   */
  enum dma_sync_target {
  	SYNC_FOR_CPU = 0,
  	SYNC_FOR_DEVICE = 1,
  };
  
  extern phys_addr_t swiotlb_tbl_map_single(struct device *hwdev,
  					  dma_addr_t tbl_dma_addr,
  					  phys_addr_t phys,
  					  size_t mapping_size,
  					  size_t alloc_size,
  					  enum dma_data_direction dir,
  					  unsigned long attrs);
  
  extern void swiotlb_tbl_unmap_single(struct device *hwdev,
  				     phys_addr_t tlb_addr,
  				     size_t mapping_size,
  				     size_t alloc_size,
  				     enum dma_data_direction dir,
  				     unsigned long attrs);
  
  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);
  
  #ifdef CONFIG_SWIOTLB
  extern enum swiotlb_force swiotlb_force;
  extern phys_addr_t io_tlb_start, io_tlb_end;
  
  static inline bool is_swiotlb_buffer(phys_addr_t paddr)
  {
  	return paddr >= io_tlb_start && paddr < io_tlb_end;
  }
  
  bool swiotlb_map(struct device *dev, phys_addr_t *phys, dma_addr_t *dma_addr,
  		size_t size, enum dma_data_direction dir, unsigned long attrs);
  void __init swiotlb_exit(void);
  unsigned int swiotlb_max_segment(void);
  size_t swiotlb_max_mapping_size(struct device *dev);
  bool is_swiotlb_active(void);
  #else
  #define swiotlb_force SWIOTLB_NO_FORCE
  static inline bool is_swiotlb_buffer(phys_addr_t paddr)
  {
  	return false;
  }
  static inline bool swiotlb_map(struct device *dev, phys_addr_t *phys,
  		dma_addr_t *dma_addr, size_t size, enum dma_data_direction dir,
  		unsigned long attrs)
  {
  	return false;
  }
  static inline void swiotlb_exit(void)
  {
  }
  static inline unsigned int swiotlb_max_segment(void)
  {
  	return 0;
  }
  static inline size_t swiotlb_max_mapping_size(struct device *dev)
  {
  	return SIZE_MAX;
  }
  
  static inline bool is_swiotlb_active(void)
  {
  	return false;
  }
  #endif /* CONFIG_SWIOTLB */
  
  extern void swiotlb_print_info(void);
  extern void swiotlb_set_max_segment(unsigned int);
  
  #endif /* __LINUX_SWIOTLB_H */
  