ddi_dma_movwin(9f)

1ddi_dma_movwin(9F)       Kernel Functions for Drivers       ddi_dma_movwin(9F)
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NAME

6       ddi_dma_movwin - shift current DMA window
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SYNOPSIS

9       #include <sys/ddi.h>
10       #include <sys/sunddi.h>
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14       int ddi_dma_movwin(ddi_dma_handle_t handle, off_t *offp,
15            uint_t *lenp, ddi_dma_cookie_t *cookiep);
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INTERFACE LEVEL

19       This interface is obsolete.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

22       handle     The DMA handle filled in by a call to ddi_dma_setup(9F).
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25       offp       A pointer to an offset to set the DMA window to. Upon a suc‐
26                  cessful return, it will be filled in  with  the  new  offset
27                  from  the  beginning  of  the object resources are allocated
28                  for.
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31       lenp       A pointer to a value which must either be the  current  size
32                  of  the  DMA  window  (as  known from a call to ddi_dma_cur‐
33                  win(9F) or from a previous call to ddi_dma_movwin()). Upon a
34                  successful  return,  it  will be filled in with the size, in
35                  bytes, of the current window.
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38       cookiep    A pointer to a DMA cookie (see ddi_dma_cookie(9S)).  Upon  a
39                  successful  return,  cookiep  is  filled  in  just  as if an
40                  implicit ddi_dma_htoc(9F) had been made.
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DESCRIPTION

44       The ddi_dma_movwin() function shifts the current DMA window. If  a  DMA
45       request  allows  the  system  to  allocate  resources for less than the
46       entire  object   by   setting   the   DDI_DMA_PARTIAL   flag   in   the
47       ddi_dma_req(9S)  structure,  the current DMA window can be shifted by a
48       call to ddi_dma_movwin().
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51       The caller must first determine the current DMA window size by  a  call
52       to  ddi_dma_curwin(9F). Using the current offset and size of the window
53       thus retrieved, the caller of ddi_dma_movwin() may  change  the  window
54       onto  the object by changing the offset by a value which is some multi‐
55       ple of the size of the DMA window.
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58       The ddi_dma_movwin() function takes care of  underlying  resource  syn‐
59       chronizations  required  to  shift  the window. However, if you want to
60       access the data prior to or after moving the window,  further  synchro‐
61       nizations using ddi_dma_sync(9F) are required.
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64       This  function  is normally called from an interrupt routine. The first
65       invocation of the DMA engine is done from the  driver.  All  subsequent
66       invocations  of the DMA engine are done from the interrupt routine. The
67       interrupt routine checks to see if the request has been  completed.  If
68       it  has, it returns without invoking another DMA transfer. Otherwise it
69       calls ddi_dma_movwin() to shift the current window and  starts  another
70       DMA transfer.
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RETURN VALUES

73       The ddi_dma_movwin() function returns:
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75       DDI_SUCCESS    The  current  length  and offset are legal and have been
76                      set.
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79       DDI_FAILURE    Otherwise.
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CONTEXT

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

87       See attributes(5) for a description of the following attributes:
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92       ┌─────────────────────────────┬─────────────────────────────┐
93       │      ATTRIBUTE TYPE         │      ATTRIBUTE VALUE        │
94       ├─────────────────────────────┼─────────────────────────────┤
95       │Stability Level              │Obsolete                     │
96       └─────────────────────────────┴─────────────────────────────┘
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WARNINGS

107       The  caller  must  guarantee  that the resources used by the object are
108       inactive prior to calling this function.
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112SunOS 5.11                        16 Jan 2006               ddi_dma_movwin(9F)