Kernel Functions for Drivers                   ddiiopballoc(9F)



NAME
     ddiiopballoc,  ddiiopbfree  -  allocate  and  free  non-
     sequentially accessed memory

SYNOPSIS
     #include 
     #include 

     int ddiiopballoc(devinfot *dip, ddidmalimt *limits,
          uintt length, caddrt *iopbp);


     void ddiiopbfree(caddrt iopb);


INTERFACE LEVEL
     These interfaces  are  obsolete.  Use  ddidmamemalloc(9F)
     instead   of   ddiiopballoc().   Use  ddidmamemfree(9F)
     instead of ddiiopbfree().

PARAMETERS
  ddiiopballoc()
     dip       A pointer to the device's devinfo structure.


     limits    A pointer to a DMA limits structure for this  dev-
               ice       (see       ddidmalimsparc(9S)      or
               ddidmalimx86(9S)). If this pointer is  NUL,  a
               default set of DMA limits is assumed.


     length    The length in bytes of the desired allocation.


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


  ddiiopbfree()
     iopb    The  iopb  returned  from  a  successful   call   to
             ddiiopballoc().


DESCRIPTION
     The  ddiiopballoc()  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 ddidmasync(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                   ddiiopballoc(9F)



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


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


     The ddiiopbfree() function frees up  memory  allocated  by
     ddiiopballoc().

RETURN VALUES
     The ddiiopballoc() function returns:

     DISUCES    Memory successfully allocated.


     DIFAILURE    Allocation failed.


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

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



     
           ATRIBUTE TYPE               ATRIBUTE VALUE       
    
     Stability Level              Obsolete                    
    


SEE ALSO
     attributes(5),   ddidmafree(9F),    ddidmamemalloc(9F),
     ddidmamemfree(9F),  ddidmasetup(9F),  ddidmasync(9F),
     ddimemalloc(9F),                    ddidmalimsparc(9S),
     ddidmalimx86(9S), ddidmareq(9S)


     Writing Device Drivers

NOTES




SunOS 5.11          Last change: 04 Apr 2006                    2






Kernel Functions for Drivers                   ddiiopballoc(9F)



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





















































SunOS 5.11          Last change: 04 Apr 2006                    3