Manual Pages for UNIX Operating System command usage for man ddi_iopb_alloc

Kernel Functions for Drivers                   ddi_iopb_alloc(9F)



NAME
     ddi_iopb_alloc,  ddi_iopb_free  -  allocate  and  free  non-
     sequentially accessed memory

SYNOPSIS
     #include 
     #include 

     int ddi_iopb_alloc(dev_info_t *dip, ddi_dma_lim_t *limits,
          uint_t length, caddr_t *iopbp);


     void ddi_iopb_free(caddr_t iopb);


INTERFACE LEVEL
     These interfaces  are  obsolete.  Use  ddi_dma_mem_alloc(9F)
     instead   of   ddi_iopb_alloc().   Use  ddi_dma_mem_free(9F)
     instead of ddi_iopb_free().

PARAMETERS
  ddi_iopb_alloc()
     dip       A pointer to the device's dev_info structure.


     limits    A pointer to a DMA limits structure for this  dev-
               ice       (see       ddi_dma_lim_sparc(9S)      or
               ddi_dma_lim_x86(9S)). If this pointer is  NULL,  a
               default set of DMA limits is assumed.


     length    The length in bytes of the desired allocation.


     iopbp     A pointer to a caddr_t. On  a  successful  return,
               *iopbp points to the allocated storage.


  ddi_iopb_free()
     iopb    The  iopb  returned  from  a  successful   call   to
             ddi_iopb_alloc().


DESCRIPTION
     The  ddi_iopb_alloc()  function  allocates  memory  for  DMA
     transfers  and  should be used if the device accesses memory
     in a non-sequential fashion,  or  if  synchronization  steps
     using ddi_dma_sync(9F) should be as lightweight as possible,
     due to frequent use on small objects. This type of access is
     commonly  known  as  consistent  access. The allocation will
     obey the alignment and padding constraints as  specified  in
     the limits argument and other limits imposed by the system.



SunOS 5.11          Last change: 04 Apr 2006                    1






Kernel Functions for Drivers                   ddi_iopb_alloc(9F)



     Note that you still must use DMA resource  allocation  func-
     tions (see ddi_dma_setup(9F)) to establish DMA resources for
     the memory allocated using ddi_iopb_alloc().


     In order to make the view of a memory object shared  between
     a  CPU and a DMA device consistent, explicit synchronization
     steps using ddi_dma_sync(9F) or ddi_dma_free(9F)  are  still
     required.  The DMA resources will be allocated so that these
     synchronization steps are as efficient as possible.


     The ddi_iopb_free() function frees up  memory  allocated  by
     ddi_iopb_alloc().

RETURN VALUES
     The ddi_iopb_alloc() function returns:

     DDI_SUCCESS    Memory successfully allocated.


     DDI_FAILURE    Allocation failed.


CONTEXT
     These functions can be called from user, interrupt, or  ker-
     nel context.

ATTRIBUTES
     See attributes(5) for a description of the following  attri-
     butes:



     ____________________________________________________________
    |       ATTRIBUTE TYPE        |       ATTRIBUTE VALUE       |
    |_____________________________|_____________________________|
    | Interface Stability         | Obsolete                    |
    |_____________________________|_____________________________|


SEE ALSO
     attributes(5),   ddi_dma_free(9F),    ddi_dma_mem_alloc(9F),
     ddi_dma_mem_free(9F),  ddi_dma_setup(9F),  ddi_dma_sync(9F),
     ddi_mem_alloc(9F),                    ddi_dma_lim_sparc(9S),
     ddi_dma_lim_x86(9S), ddi_dma_req(9S)


     Writing Device Drivers

NOTES




SunOS 5.11          Last change: 04 Apr 2006                    2






Kernel Functions for Drivers                   ddi_iopb_alloc(9F)



     This function uses scarce system resources.  Use  it  selec-
     tively.





















































SunOS 5.11          Last change: 04 Apr 2006                    3