Manual Pages for UNIX Operating System command usage for man ddi_dma_movwin

Kernel Functions for Drivers                   ddi_dma_movwin(9F)



NAME
     ddi_dma_movwin - shift current DMA window

SYNOPSIS
     #include 
     #include 



     int ddi_dma_movwin(ddi_dma_handle_t handle, off_t *offp,
          uint_t *lenp, ddi_dma_cookie_t *cookiep);


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     This interface is  obsolete.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

PARAMETERS
     handle     The  DMA  handle  filled  in   by   a   call   to
                ddi_dma_setup(9F).


     offp       A pointer to an offset to set the DMA window  to.
                Upon  a  successful  return, it will be filled in
                with the new offset from  the  beginning  of  the
                object resources are allocated for.


     lenp       A pointer to a value which  must  either  be  the
                current  size  of the DMA window (as known from a
                call to ddi_dma_curwin(9F)  or  from  a  previous
                call  to  ddi_dma_movwin()).  Upon  a  successful
                return, it will be filled in with  the  size,  in
                bytes, of the current window.


     cookiep    A    pointer    to    a    DMA    cookie     (see
                ddi_dma_cookie(9S)).  Upon  a  successful return,
                cookiep is filled  in  just  as  if  an  implicit
                ddi_dma_htoc(9F) had been made.


DESCRIPTION
     The ddi_dma_movwin() function shifts the current DMA window.
     If a DMA request allows the system to allocate resources for
     less than the entire object by setting  the  DDI_DMA_PARTIAL
     flag  in the ddi_dma_req(9S) structure, the current DMA win-
     dow can be shifted by a call to ddi_dma_movwin().


     The caller must first determine the current DMA window  size
     by  a  call  to ddi_dma_curwin(9F). Using the current offset



SunOS 5.11          Last change: 16 Jan 2006                    1






Kernel Functions for Drivers                   ddi_dma_movwin(9F)



     and size  of  the  window  thus  retrieved,  the  caller  of
     ddi_dma_movwin()  may  change  the window onto the object by
     changing the offset by a value which is some multiple of the
     size of the DMA window.


     The  ddi_dma_movwin()  function  takes  care  of  underlying
     resource synchronizations required to shift the window. How-
     ever, if you want to access the data prior to or after  mov-
     ing    the    window,    further    synchronizations   using
     ddi_dma_sync(9F) are required.


     This function is normally called from an interrupt  routine.
     The  first  invocation  of  the  DMA engine is done from the
     driver. All subsequent invocations of  the  DMA  engine  are
     done  from  the  interrupt  routine.  The  interrupt routine
     checks to see if the request has been completed. If it  has,
     it  returns without invoking another DMA transfer. Otherwise
     it calls ddi_dma_movwin() to shift the  current  window  and
     starts another DMA transfer.

RETURN VALUES
     The ddi_dma_movwin() function returns:

     DDI_SUCCESS    The current length and offset are  legal  and
                    have been set.


     DDI_FAILURE    Otherwise.


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

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



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


SEE ALSO
     attributes(5),    ddi_dma_curwin(9F),    ddi_dma_getwin(9F),
     ddi_dma_htoc(9F),    ddi_dma_setup(9F),    ddi_dma_sync(9F),



SunOS 5.11          Last change: 16 Jan 2006                    2






Kernel Functions for Drivers                   ddi_dma_movwin(9F)



     ddi_dma_cookie(9S), ddi_dma_req(9S)


     Writing Device Drivers

WARNINGS
     The caller must guarantee that the  resources  used  by  the
     object are inactive prior to calling this function.















































SunOS 5.11          Last change: 16 Jan 2006                    3