ddi_dma_nextwin(9f) [xfree86 man page]

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

NAME

       ddi_dma_nextwin - get next DMA window

SYNOPSIS

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

       int ddi_dma_nextwin(ddi_dma_handle_t handle, ddi_dma_win_t win, ddi_dma_win_t *nwin);

INTERFACE LEVEL

       This interface is obsolete.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

PARAMETERS

       handle	       A DMA handle.

       win	       The current  DMA window or NULL.

       nwin	       A  pointer  to  the  next  DMA  window  to be filled in. If win is NULL, a pointer to the first window within the object is
		       returned.

DESCRIPTION

       ddi_dma_nextwin() shifts the current DMA window	win within the object referred to by handle to the next DMA window nwin.  If  the  current
       window  is NULL, the first window within the object is returned. A DMA window is a portion of a DMA object or might be the entire object. A
       DMA window has system resources allocated to it and is prepared to accept data transfers.  Examples of system resources	are  DVMA  mapping
       resources and intermediate transfer buffer resources.

       All  DMA  objects require a window. If the DMA window represents the whole DMA object it has system resources allocated for the entire data
       transfer. However, if the system is unable to setup the entire DMA object due to system resource limitations, the driver writer	may  allow
       the  system  to	allocate  system resources for less than the entire DMA object. This can be accomplished by specifying the DDI_DMA_PARTIAL
       flag as a parameter to ddi_dma_buf_setup(9F) or ddi_dma_addr_setup(9F) or as part of a ddi_dma_req(9S) structure in a call to  ddi_dma_set-
       up(9F).

       Only  the  window  that	has  resources allocated is valid per object at any one time.  The currently valid window is the one that was most
       recently returned from ddi_dma_nextwin(). Furthermore, because a call to ddi_dma_nextwin() will reallocate system resources to the new win-
       dow, the previous window will become invalid.   It is a severe error to call ddi_dma_nextwin() before any transfers into the current window
       are complete.

       ddi_dma_nextwin() takes care of underlying memory synchronizations required to shift the window. However, if you want to  access  the  data
       before or after moving the window, further synchronizations using ddi_dma_sync(9F) are required.

RETURN VALUES

       ddi_dma_nextwin() returns:

       DDI_SUCCESS     Successfully filled in the next window pointer.

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

       DDI_DMA_STALE   win does not refer to the currently active window.

CONTEXT

       ddi_dma_nextwin() 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_getwin(9F),   ddi_dma_nextseg(9F),   ddi_dma_segtocookie(9F),
       ddi_dma_sync(9F), ddi_dma_req(9S)

       Writing Device Drivers

SunOS 5.10							    27 Sep 2002 					       ddi_dma_nextwin(9F)

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

NAME

       ddi_dma_nextwin - get next DMA window

SYNOPSIS

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

       int ddi_dma_nextwin(ddi_dma_handle_t handle, ddi_dma_win_t win, ddi_dma_win_t *nwin);

INTERFACE LEVEL

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

PARAMETERS

       handle	       A DMA handle.

       win	       The current  DMA window or NULL.

       nwin	       A  pointer  to  the  next  DMA  window  to be filled in. If win is NULL, a pointer to the first window within the object is
		       returned.

DESCRIPTION

       ddi_dma_nextwin() shifts the current DMA window	win within the object referred to by handle to the next DMA window nwin.  If  the  current
       window  is NULL, the first window within the object is returned. A DMA window is a portion of a DMA object or might be the entire object. A
       DMA window has system resources allocated to it and is prepared to accept data transfers.  Examples of system resources	are  DVMA  mapping
       resources and intermediate transfer buffer resources.

       All  DMA  objects require a window. If the DMA window represents the whole DMA object it has system resources allocated for the entire data
       transfer. However, if the system is unable to setup the entire DMA object due to system resource limitations, the driver writer	may  allow
       the  system  to	allocate  system resources for less than the entire DMA object. This can be accomplished by specifying the DDI_DMA_PARTIAL
       flag as a parameter to ddi_dma_buf_setup(9F) or ddi_dma_addr_setup(9F) or as part of a ddi_dma_req(9S) structure in a call to  ddi_dma_set-
       up(9F).

       Only  the  window  that	has  resources allocated is valid per object at any one time.  The currently valid window is the one that was most
       recently returned from ddi_dma_nextwin(). Furthermore, because a call to ddi_dma_nextwin() will reallocate system resources to the new win-
       dow, the previous window will become invalid.   It is a severe error to call ddi_dma_nextwin() before any transfers into the current window
       are complete.

       ddi_dma_nextwin() takes care of underlying memory synchronizations required to shift the window. However, if you want to  access  the  data
       before or after moving the window, further synchronizations using ddi_dma_sync(9F) are required.

RETURN VALUES

       ddi_dma_nextwin() returns:

       DDI_SUCCESS     Successfully filled in the next window pointer.

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

       DDI_DMA_STALE   win does not refer to the currently active window.

CONTEXT

       ddi_dma_nextwin() 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_getwin(9F),   ddi_dma_nextseg(9F),   ddi_dma_segtocookie(9F),
       ddi_dma_sync(9F), ddi_dma_req(9S)

       Writing Device Drivers

SunOS 5.10							    27 Sep 2002 					       ddi_dma_nextwin(9F)