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ddi_dma_nextseg(9f) [sunos man page]

ddi_dma_nextseg(9F)					   Kernel Functions for Drivers 				       ddi_dma_nextseg(9F)

NAME

       ddi_dma_nextseg - get next DMA segment

SYNOPSIS

       #include <sys/ddi.h>
       #include <sys/sunddi.h>

       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       This interface is obsolete.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 win-
		       dow is returned.

DESCRIPTION

       ddi_dma_nextseg() 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-con-
       tiguous.  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 example the object will be broken into smaller addressable DMA segments.

RETURN VALUES

       ddi_dma_nextseg() returns:

       DDI_SUCCESS	       Successfully filled in the next segment pointer.

       DDI_DMA_DONE	       There is no next segment. The current segment is the final segment within the specified window.

       DDI_DMA_STALE	       win does not refer to the currently active window.

CONTEXT

       ddi_dma_nextseg() can be called from user or interrupt context.

EXAMPLES

       For an example, see ddi_dma_segtocookie(9F).

ATTRIBUTES

       See attributes(5) for a description of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Stability Level 	     |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 5.10							    27 Sep 2002 					       ddi_dma_nextseg(9F)

Check Out this Related Man Page

ddi_dma_segtocookie(9F) 				   Kernel Functions for Drivers 				   ddi_dma_segtocookie(9F)

NAME

       ddi_dma_segtocookie - convert a DMA segment to a DMA address cookie

SYNOPSIS

       #include <sys/ddi.h>
       #include <sys/sunddi.h>

       int ddi_dma_segtocookie(ddi_dma_seg_t seg, off_t *offp, off_t *lenp, ddi_dma_cookie_t *cookiep);

INTERFACE LEVEL

       This interface is obsolete.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

PARAMETERS

       seg	       A DMA segment.

       offp	       A  pointer  to  an  off_t. Upon a successful return, it is filled in with the offset. This segment is addressing within the
		       object.

       lenp	       The byte length. This segment is addressing within the object.

       cookiep	       A pointer to a DMA cookie (see ddi_dma_cookie(9S)).

DESCRIPTION

       ddi_dma_segtocookie() takes a DMA segment and fills in the cookie pointed to by cookiep with the appropriate address, length, and bus  type
       to be used to program the DMA engine. ddi_dma_segtocookie() also fills in *offp and *lenp, which specify the range within the object.

RETURN VALUES

       ddi_dma_segtocookie() returns:

       DDI_SUCCESS	       Successfully filled in all values.

       DDI_FAILURE	       Failed to successfully fill in all values.

CONTEXT

       ddi_dma_segtocookie() can be called from user or interrupt context.

EXAMPLES

       Example 1: ddi_dma_segtocookie() example

       for (win = NULL; (retw = ddi_dma_nextwin(handle, win, &nwin)) !=
	   DDI_DMA_DONE; win = nwin) {
	    if (retw != DDI_SUCCESS) {
		 /* do error handling */
	    } else {
		 for (seg = NULL; (rets = ddi_dma_nextseg(nwin, seg, &nseg)) !=
		     DDI_DMA_DONE; seg = nseg) {
		      if (rets != DDI_SUCCESS) {

			   /* do error handling */
		      } else {
			   ddi_dma_segtocookie(nseg, &off, &len, &cookie);

			   /* program DMA engine */
		      }
		 }
	    }
       }

ATTRIBUTES

       See attributes(5) for a description of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Stability Level 	     |Obsolete			   |
       +-----------------------------+-----------------------------+

SEE ALSO

       attributes(5), ddi_dma_nextcookie(9F). ddi_dma_nextseg(9F), ddi_dma_nextwin(9F), ddi_dma_sync(9F), ddi_dma_cookie(9S)

       Writing Device Drivers

SunOS 5.10							    27 Sep 2002 					   ddi_dma_segtocookie(9F)
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