include/asm-generic/scatterlist.h

   1 #ifndef __ASM_GENERIC_SCATTERLIST_H
   2 #define __ASM_GENERIC_SCATTERLIST_H
   3
   4 #include <linux/types.h>
   5
   6 struct scatterlist {
   7 #ifdef CONFIG_DEBUG_SG
   8         unsigned long   sg_magic;
   9 #endif
  10         unsigned long   page_link;
  11         unsigned int    offset;
  12         unsigned int    length;
  13         dma_addr_t      dma_address;
  14         unsigned int    dma_length;
  15 };
  16
  17 /*
  18  * These macros should be used after a dma_map_sg call has been done
  19  * to get bus addresses of each of the SG entries and their lengths.
  20  * You should only work with the number of sg entries pci_map_sg
  21  * returns, or alternatively stop on the first sg_dma_len(sg) which
  22  * is 0.
  23  */
  24 #define sg_dma_address(sg)      ((sg)->dma_address)
  25 #ifndef sg_dma_len
  26 /*
  27  * Normally, you have an iommu on 64 bit machines, but not on 32 bit
  28  * machines. Architectures that are differnt should override this.
  29  */
  30 #if __BITS_PER_LONG == 64
  31 #define sg_dma_len(sg)          ((sg)->dma_length)
  32 #else
  33 #define sg_dma_len(sg)          ((sg)->length)
  34 #endif /* 64 bit */
  35 #endif /* sg_dma_len */
  36
  37 #ifndef ISA_DMA_THRESHOLD
  38 #define ISA_DMA_THRESHOLD       (~0UL)
  39 #endif
  40
  41 #define ARCH_HAS_SG_CHAIN
  42
  43 #endif /* __ASM_GENERIC_SCATTERLIST_H */