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6 .TH DDI_DMA_NEXTWIN 9F "Jan 16, 2006"
8 ddi_dma_nextwin \- get next DMA window
13 #include <sys/sunddi.h>
17 \fBint\fR \fBddi_dma_nextwin\fR(\fBddi_dma_handle_t\fR \fIhandle\fR, \fBddi_dma_win_t\fR \fIwin\fR,
18 \fBddi_dma_win_t *\fR\fInwin\fR);
24 This interface is obsolete. \fBddi_dma_getwin\fR(9F) should be used instead.
41 The current \fBDMA\fR window or \fINULL\fR.
50 A pointer to the next \fBDMA\fR window to be filled in. If \fIwin\fR is
51 \fINULL\fR, a pointer to the first window within the object is returned.
57 The \fBddi_dma_nextwin()\fR function shifts the current \fBDMA\fR window
58 \fIwin\fR within the object referred to by \fIhandle\fR to the next \fBDMA\fR
59 window \fInwin\fR. If the current window is \fINULL\fR, the first window within
60 the object is returned. A \fBDMA\fR window is a portion of a \fBDMA\fR object
61 or might be the entire object. A \fBDMA\fR window has system resources
62 allocated to it and is prepared to accept data transfers. Examples of system
63 resources are \fBDVMA\fR mapping resources and intermediate transfer buffer
67 All \fBDMA\fR objects require a window. If the \fBDMA\fR window represents the
68 whole \fBDMA\fR object it has system resources allocated for the entire data
69 transfer. However, if the system is unable to setup the entire \fBDMA\fR object
70 due to system resource limitations, the driver writer may allow the system to
71 allocate system resources for less than the entire \fBDMA\fR object. This can
72 be accomplished by specifying the \fBDDI_DMA_PARTIAL\fR flag as a parameter to
73 \fBddi_dma_buf_setup\fR(9F) or \fBddi_dma_addr_setup\fR(9F) or as part of a
74 \fBddi_dma_req\fR(9S) structure in a call to \fBddi_dma_setup\fR(9F).
77 Only the window that has resources allocated is valid per object at any one
78 time. The currently valid window is the one that was most recently returned
79 from \fBddi_dma_nextwin()\fR. Furthermore, because a call to
80 \fBddi_dma_nextwin()\fR will reallocate system resources to the new window, the
81 previous window will become invalid. It is a \fBsevere\fR error to call
82 \fBddi_dma_nextwin()\fR before any transfers into the current window are
86 The \fBddi_dma_nextwin()\fR function takes care of underlying memory
87 synchronizations required to shift the window. However, if you want to access
88 the data before or after moving the window, further synchronizations using
89 \fBddi_dma_sync\fR(9F) are required.
93 The \fBddi_dma_nextwin()\fR function returns:
97 \fB\fBDDI_SUCCESS\fR\fR
100 Successfully filled in the next window pointer.
106 \fB\fBDDI_DMA_DONE\fR\fR
109 There is no next window. The current window is the final window within the
116 \fB\fBDDI_DMA_STALE\fR\fR
119 \fIwin\fR does not refer to the currently active window.
125 The \fBddi_dma_nextwin()\fR function can be called from user, interrupt, or
130 For an example see \fBddi_dma_segtocookie\fR(9F).
134 See \fBattributes\fR(5) for a description of the following attributes:
142 ATTRIBUTE TYPE ATTRIBUTE VALUE
144 Stability Level Obsolete
150 \fBattributes\fR(5), \fBddi_dma_addr_setup\fR(9F), \fBddi_dma_buf_setup\fR(9F),
151 \fBddi_dma_getwin\fR(9F), \fBddi_dma_nextseg\fR(9F),
152 \fBddi_dma_segtocookie\fR(9F), \fBddi_dma_sync\fR(9F), \fBddi_dma_req\fR(9S)
155 \fIWriting Device Drivers\fR