ddi_iopb_free(9f)

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

6       ddi_iopb_alloc,  ddi_iopb_free  -  allocate  and  free non-sequentially
7       accessed memory
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SYNOPSIS

10       #include <sys/ddi.h>
11       #include <sys/sunddi.h>
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13       int ddi_iopb_alloc(dev_info_t *dip, ddi_dma_lim_t *limits,
14            uint_t length, caddr_t *iopbp);
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17       void ddi_iopb_free(caddr_t iopb);
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INTERFACE LEVEL

21       These interfaces are obsolete.  Use  ddi_dma_mem_alloc(9F)  instead  of
22       ddi_iopb_alloc(). Use ddi_dma_mem_free(9F) instead of ddi_iopb_free().
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PARAMETERS

25   ddi_iopb_alloc()
26       dip       A pointer to the device's dev_info structure.
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29       limits    A  pointer  to  a  DMA  limits structure for this device (see
30                 ddi_dma_lim_sparc(9S)  or   ddi_dma_lim_x86(9S)).   If   this
31                 pointer is NULL, a default set of DMA limits is assumed.
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34       length    The length in bytes of the desired allocation.
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37       iopbp     A pointer to a caddr_t. On a successful return, *iopbp points
38                 to the allocated storage.
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41   ddi_iopb_free()
42       iopb    The iopb returned from a successful call to ddi_iopb_alloc().
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DESCRIPTION

46       The ddi_iopb_alloc() function allocates memory for  DMA  transfers  and
47       should  be used if the device accesses memory in a non-sequential fash‐
48       ion, or if synchronization steps using ddi_dma_sync(9F)  should  be  as
49       lightweight  as  possible,  due  to frequent use on small objects. This
50       type of access is commonly known as consistent access.  The  allocation
51       will  obey  the  alignment  and padding constraints as specified in the
52       limits argument and other limits imposed by the system.
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55       Note that you still must use DMA  resource  allocation  functions  (see
56       ddi_dma_setup(9F))  to establish DMA resources for the memory allocated
57       using ddi_iopb_alloc().
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60       In order to make the view of a memory object shared between a CPU and a
61       DMA   device   consistent,   explicit   synchronization   steps   using
62       ddi_dma_sync(9F)  or  ddi_dma_free(9F)  are  still  required.  The  DMA
63       resources  will be allocated so that these synchronization steps are as
64       efficient as possible.
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67       The   ddi_iopb_free()   function   frees   up   memory   allocated   by
68       ddi_iopb_alloc().
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RETURN VALUES

71       The ddi_iopb_alloc() function returns:
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73       DDI_SUCCESS    Memory successfully allocated.
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76       DDI_FAILURE    Allocation failed.
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CONTEXT

80       These functions can be called from user, interrupt, or kernel context.
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ATTRIBUTES

83       See attributes(5) for a description of the following attributes:
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88       ┌─────────────────────────────┬─────────────────────────────┐
89       │      ATTRIBUTE TYPE         │      ATTRIBUTE VALUE        │
90       ├─────────────────────────────┼─────────────────────────────┤
91       │Stability Level              │Obsolete                     │
92       └─────────────────────────────┴─────────────────────────────┘
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NOTES

104       This function uses scarce system resources. Use it selectively.
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108SunOS 5.11                        04 Apr 2006               ddi_iopb_alloc(9F)