include/asm-frv/scatterlist.h

   1 #ifndef _ASM_SCATTERLIST_H
   2 #define _ASM_SCATTERLIST_H
   3
   4 /*
   5  * Drivers must set either ->address or (preferred) ->page and ->offset
   6  * to indicate where data must be transferred to/from.
   7  *
   8  * Using ->page is recommended since it handles highmem data as well as
   9  * low mem. ->address is restricted to data which has a virtual mapping, and
  10  * it will go away in the future. Updating to ->page can be automated very
  11  * easily -- something like
  12  *
  13  * sg->address = some_ptr;
  14  *
  15  * can be rewritten as
  16  *
  17  * sg->page = virt_to_page(some_ptr);
  18  * sg->offset = (unsigned long) some_ptr & ~PAGE_MASK;
  19  *
  20  * and that's it. There's no excuse for not highmem enabling YOUR driver. /jens
  21  */
  22 struct scatterlist {
  23         struct page     *page;          /* Location for highmem page, if any */
  24         unsigned int    offset;         /* for highmem, page offset */
  25
  26         dma_addr_t      dma_address;
  27         unsigned int    length;
  28 };
  29
  30 #define ISA_DMA_THRESHOLD (0xffffffffUL)
  31
  32 #endif /* !_ASM_SCATTERLIST_H */