include/asm-frv/scatterlist.h

   1 #ifndef _ASM_SCATTERLIST_H
   2 #define _ASM_SCATTERLIST_H
   3
   4 #include <asm/types.h>
   5
   6 /*
   7  * Drivers must set either ->address or (preferred) ->page and ->offset
   8  * to indicate where data must be transferred to/from.
   9  *
  10  * Using ->page is recommended since it handles highmem data as well as
  11  * low mem. ->address is restricted to data which has a virtual mapping, and
  12  * it will go away in the future. Updating to ->page can be automated very
  13  * easily -- something like
  14  *
  15  * sg->address = some_ptr;
  16  *
  17  * can be rewritten as
  18  *
  19  * sg->page = virt_to_page(some_ptr);
  20  * sg->offset = (unsigned long) some_ptr & ~PAGE_MASK;
  21  *
  22  * and that's it. There's no excuse for not highmem enabling YOUR driver. /jens
  23  */
  24 struct scatterlist {
  25         struct page     *page;          /* Location for highmem page, if any */
  26         unsigned int    offset;         /* for highmem, page offset */
  27
  28         dma_addr_t      dma_address;
  29         unsigned int    length;
  30 };
  31
  32 #define ISA_DMA_THRESHOLD (0xffffffffUL)
  33
  34 #endif /* !_ASM_SCATTERLIST_H */