text: /*
   * DMA region bookkeeping routines
   *
   * Copyright (C) 2002 Maas Digital LLC
   *
   * This code is licensed under the GPL.  See the file COPYING in the root
   * directory of the kernel sources for details.
   */
  
  #ifndef IEEE1394_DMA_H
  #define IEEE1394_DMA_H
  
  #include <linux/pci.h>
  #include <asm/scatterlist.h>
  
  /* struct dma_prog_region
  
     a small, physically-contiguous DMA buffer with random-access,
     synchronous usage characteristics
  */
  
  struct dma_prog_region {
  	unsigned char    *kvirt;     /* kernel virtual address */
  	struct pci_dev   *dev;       /* PCI device */
  	unsigned int      n_pages;   /* # of kernel pages */
  	dma_addr_t        bus_addr;  /* base bus address */
  };
  
  /* clear out all fields but do not allocate any memory */
  void dma_prog_region_init(struct dma_prog_region *prog);
  int  dma_prog_region_alloc(struct dma_prog_region *prog, unsigned long n_bytes, struct pci_dev *dev);
  void dma_prog_region_free(struct dma_prog_region *prog);
  
  static inline dma_addr_t dma_prog_region_offset_to_bus(struct dma_prog_region *prog, unsigned long offset)
  {
  	return prog->bus_addr + offset;
  }
  
  /* struct dma_region
  
     a large, non-physically-contiguous DMA buffer with streaming,
     asynchronous usage characteristics
  */
  
  struct dma_region {
  	unsigned char      *kvirt;       /* kernel virtual address */
  	struct pci_dev     *dev;         /* PCI device */
  	unsigned int        n_pages;     /* # of kernel pages */
  	unsigned int        n_dma_pages; /* # of IOMMU pages */
  	struct scatterlist *sglist;      /* IOMMU mapping */
  	int                 direction;   /* PCI_DMA_TODEVICE, etc */
  };
  
  /* clear out all fields but do not allocate anything */
  void dma_region_init(struct dma_region *dma);
  
  /* allocate the buffer and map it to the IOMMU */
  int  dma_region_alloc(struct dma_region *dma, unsigned long n_bytes, struct pci_dev *dev, int direction);
  
  /* unmap and free the buffer */
  void dma_region_free(struct dma_region *dma);
  
  /* sync the CPU's view of the buffer */
  void dma_region_sync_for_cpu(struct dma_region *dma, unsigned long offset, unsigned long len);
  /* sync the IO bus' view of the buffer */
  void dma_region_sync_for_device(struct dma_region *dma, unsigned long offset, unsigned long len);
  
  /* map the buffer into a user space process */
  int  dma_region_mmap(struct dma_region *dma, struct file *file, struct vm_area_struct *vma);
  
  /* macro to index into a DMA region (or dma_prog_region) */
  #define dma_region_i(_dma, _type, _index) ( ((_type*) ((_dma)->kvirt)) + (_index) )
  
  /* return the DMA bus address of the byte with the given offset
     relative to the beginning of the dma_region */
  dma_addr_t dma_region_offset_to_bus(struct dma_region *dma, unsigned long offset);
  
  #endif /* IEEE1394_DMA_H */
  