Manual Pages for UNIX Operating System command usage for man ddi_dma_nextseg

Kernel Functions for Drivers                  ddi_dma_nextseg(9F)



NAME
     ddi_dma_nextseg - get next DMA segment

SYNOPSIS
     #include 
     #include 

     int ddi_dma_nextseg(ddi_dma_win_t win, ddi_dma_seg_t seg,
          ddi_dma_seg_t *nseg);


INTERFACE LEVEL
     This interface is obsolete. ddi_dma_nextcookie(9F) should be
     used instead.

PARAMETERS
     win     A DMA window.


     seg     The current DMA segment or NULL.


     nseg    A pointer to the next DMA segment to be  filled  in.
             If  seg  is  NULL,  a  pointer  to the first segment
             within the specified window is returned.


DESCRIPTION
     The ddi_dma_nextseg() function gets  the  next  DMA  segment
     within  the  specified window win. If the current segment is
     NULL, the first DMA segment within the window is returned.


     A DMA segment is always required for a DMA  window.   A  DMA
     segment  is  a  contiguous  portion  of  a  DMA  window (see
     ddi_dma_nextwin(9F)) which is entirely  addressable  by  the
     device for a data transfer operation.


     An example where multiple  DMA  segments  are  allocated  is
     where  the system does not contain DVMA capabilities and the
     object may be non-contiguous. In  this  example  the  object
     will be broken into smaller contiguous DMA segments. Another
     example is where the device  has   an  upper  limit  on  its
     transfer  size  (for  example an 8-bit address register) and
     has  expressed  this  in  the  DMA  limit   structure   (see
     ddi_dma_lim_sparc(9S) or ddi_dma_lim_x86(9S)). In this exam-
     ple the object will be broken into smaller  addressable  DMA
     segments.

RETURN VALUES




SunOS 5.11          Last change: 04 Apr 2006                    1






Kernel Functions for Drivers                  ddi_dma_nextseg(9F)



     The ddi_dma_nextseg() function returns:

     DDI_SUCCESS      Successfully filled  in  the  next  segment
                      pointer.


     DDI_DMA_DONE     There is no next segment. The current  seg-
                      ment is the final segment within the speci-
                      fied window.


     DDI_DMA_STALE    win does not refer to the currently  active
                      window.


CONTEXT
     The ddi_dma_nextseg() function  can  be  called  from  user,
     interrupt, or kernel context.

EXAMPLES
     For an example, see ddi_dma_segtocookie(9F).

ATTRIBUTES
     See attributes(5) for a description of the following  attri-
     butes:



     ____________________________________________________________
    |       ATTRIBUTE TYPE        |       ATTRIBUTE VALUE       |
    |_____________________________|_____________________________|
    | Interface Stability         | Obsolete                    |
    |_____________________________|_____________________________|


SEE ALSO
     attributes(5),                       ddi_dma_addr_setup(9F),
     ddi_dma_buf_setup(9F),               ddi_dma_nextcookie(9F),
     ddi_dma_nextwin(9F),                ddi_dma_segtocookie(9F),
     ddi_dma_sync(9F),                     ddi_dma_lim_sparc(9S),
     ddi_dma_lim_x86(9S), ddi_dma_req(9S)


     Writing Device Drivers











SunOS 5.11          Last change: 04 Apr 2006                    2