Manual Pages for UNIX Operating System command usage for man ddi_dma_nextcookie

Kernel Functions for Drivers               ddi_dma_nextcookie(9F)



NAME
     ddi_dma_nextcookie - retrieve subsequent DMA cookie

SYNOPSIS
     #include 
     #include 



     void ddi_dma_nextcookie(ddi_dma_handle_t handle,
          ddi_dma_cookie_t *cookiep);


PARAMETERS
     handle     The handle previously  allocated  by  a  call  to
                ddi_dma_alloc_handle(9F).


     cookiep    A pointer to a  ddi_dma_cookie(9S) structure.


INTERFACE LEVEL
     Solaris DDI specific (Solaris DDI).

DESCRIPTION
     ddi_dma_nextcookie() retrieves subsequent  DMA cookies for a
     DMA    object.      ddi_dma_nextcookie()    fills   in   the
     ddi_dma_cookie(9S) structure pointed  to  by   cookiep.  The
     ddi_dma_cookie(9S) structure must be allocated prior to cal-
     ling  ddi_dma_nextcookie().


     The      DMA      cookie       count       returned       by
     ddi_dma_buf_bind_handle(9F),   ddi_dma_addr_bind_handle(9F),
     or ddi_dma_getwin(9F) indicates the number of DMA cookies  a
     DMA  object  consists of. If the resulting cookie count,  N,
     is larger than 1,  ddi_dma_nextcookie() must be  called  N-1
     times to retrieve all  DMA cookies.

CONTEXT
     ddi_dma_nextcookie() can be called  from  user,  kernel,  or
     interrupt context.

EXAMPLES
     Example 1 Process a scatter-gather list of I/O requests.


     This example demonstrates the use  of   ddi_dma_nextcookie()
     to process a scatter-gather list of I/O requests.


       /* setup scatter-gather list with multiple DMA cookies */



SunOS 5.11          Last change: 26 Sep 1994                    1






Kernel Functions for Drivers               ddi_dma_nextcookie(9F)



       ddi_dma_cookie_t  dmacookie;
       uint_t            ccount;
       ...

       status = ddi_dma_buf_bind_handle(handle, bp, DDI_DMA_READ,
            NULL, NULL, &dmacookie, &ccount);

       if (status == DDI_DMA_MAPPED) {

            /* program DMA engine with first cookie */

            while (--ccount > 0) {
                 ddi_dma_nextcookie(handle, &dmacookie);
                 /* program DMA engine with next cookie */
            }
       }
       ...


SEE ALSO
     ddi_dma_addr_bind_handle(9F),      ddi_dma_alloc_handle(9F),
     ddi_dma_buf_bind_handle(9F),      ddi_dma_unbind_handle(9F),
     ddi_dma_cookie(9S)


     Writing Device Drivers





























SunOS 5.11          Last change: 26 Sep 1994                    2