drivers/ieee1394/dma.h

   1 /*
   2  * DMA region bookkeeping routines
   3  *
   4  * Copyright (C) 2002 Maas Digital LLC
   5  *
   6  * This code is licensed under the GPL.  See the file COPYING in the root
   7  * directory of the kernel sources for details.
   8  */
   9
  10 #ifndef IEEE1394_DMA_H
  11 #define IEEE1394_DMA_H
  12
  13 #include <linux/pci.h>
  14 #include <asm/scatterlist.h>
  15
  16 /* struct dma_prog_region
  17
  18    a small, physically-contiguous DMA buffer with random-access,
  19    synchronous usage characteristics
  20 */
  21
  22 struct dma_prog_region {
  23         unsigned char    *kvirt;     /* kernel virtual address */
  24         struct pci_dev   *dev;       /* PCI device */
  25         unsigned int      n_pages;   /* # of kernel pages */
  26         dma_addr_t        bus_addr;  /* base bus address */
  27 };
  28
  29 /* clear out all fields but do not allocate any memory */
  30 void dma_prog_region_init(struct dma_prog_region *prog);
  31 int  dma_prog_region_alloc(struct dma_prog_region *prog, unsigned long n_bytes, struct pci_dev *dev);
  32 void dma_prog_region_free(struct dma_prog_region *prog);
  33
  34 static inline dma_addr_t dma_prog_region_offset_to_bus(struct dma_prog_region *prog, unsigned long offset)
  35 {
  36         return prog->bus_addr + offset;
  37 }
  38
  39 /* struct dma_region
  40
  41    a large, non-physically-contiguous DMA buffer with streaming,
  42    asynchronous usage characteristics
  43 */
  44
  45 struct dma_region {
  46         unsigned char      *kvirt;       /* kernel virtual address */
  47         struct pci_dev     *dev;         /* PCI device */
  48         unsigned int        n_pages;     /* # of kernel pages */
  49         unsigned int        n_dma_pages; /* # of IOMMU pages */
  50         struct scatterlist *sglist;      /* IOMMU mapping */
  51         int                 direction;   /* PCI_DMA_TODEVICE, etc */
  52 };
  53
  54 /* clear out all fields but do not allocate anything */
  55 void dma_region_init(struct dma_region *dma);
  56
  57 /* allocate the buffer and map it to the IOMMU */
  58 int  dma_region_alloc(struct dma_region *dma, unsigned long n_bytes, struct pci_dev *dev, int direction);
  59
  60 /* unmap and free the buffer */
  61 void dma_region_free(struct dma_region *dma);
  62
  63 /* sync the IO bus' view of the buffer with the CPU's view */
  64 void dma_region_sync(struct dma_region *dma, unsigned long offset, unsigned long len);
  65
  66 /* map the buffer into a user space process */
  67 int  dma_region_mmap(struct dma_region *dma, struct file *file, struct vm_area_struct *vma);
  68
  69 /* macro to index into a DMA region (or dma_prog_region) */
  70 #define dma_region_i(_dma, _type, _index) ( ((_type*) ((_dma)->kvirt)) + (_index) )
  71
  72 /* return the DMA bus address of the byte with the given offset
  73    relative to the beginning of the dma_region */
  74 dma_addr_t dma_region_offset_to_bus(struct dma_region *dma, unsigned long offset);
  75
  76 /* round up a number of bytes to be a multiple of the PAGE_SIZE */
  77 static inline unsigned long round_up_to_page(unsigned long len)
  78 {
  79         if (len % PAGE_SIZE)
  80                 len += PAGE_SIZE - (len % PAGE_SIZE);
  81         return len;
  82 }
  83
  84 #endif /* IEEE1394_DMA_H */