Kernel Functions for Drivers                      scsidmaget(9F)



NAME
     scsidmaget, scsidmafree - SCSI dma utility routines

SYNOPSIS
     #include 



     struct scsipkt *scsidmaget(struct scsipkt *pkt,
          opaquet dmatoken, int(*callback)(void));


     void scsidmafree(struct scsipkt *pkt);


INTERFACE LEVEL
     These interfaces are obsolete. Use scsiinitpkt(9F) instead
     of   scsidmaget().   Use  scsidestroypkt(9F)  instead  of
     scsidmafree().

PARAMETERS
     pkt         A pointer to a scsipkt(9S) structure.


     dmatoken    Pointer to an implementation dependent object.


     callback    Pointer to a callback function, or NULFUNC  or
                 SLEPFUNC.


DESCRIPTION
     The scsidmaget() function allocates DMA  resources  for  an
     already  allocated SCSI packet. pkt is a pointer to the pre-
     viously allocated SCSI packet (see scsipktalloc(9F)).


     The dmatoken parameter is a  pointer  to  an  implementation
     dependent  object  which  defines the length, direction, and
     address of the  data  transfer  associated  with  this  SCSI
     packet  (command).  The  dmatoken  must  be  a  pointer to a
     buf(9S) structure. If dmatoken is  NUL,  no  resources  are
     allocated.


     The callback parameter indicates what  scsidmaget()  should
     do when resources are not available:

     NULFUNC       Do not wait for  resources.  Return  a  NUL
                     pointer.





SunOS 5.11          Last change: 16 Jan 2006                    1






Kernel Functions for Drivers                      scsidmaget(9F)



     SLEPFUNC      Wait indefinitely for resources.


     Other Values    callback  points  to  a  function  which  is
                     called when resources may have become avail-
                     able. callback must return either  0  (indi-
                     cating   that   it   attempted  to  allocate
                     resources but failed to  do  so  again),  in
                     which  case  it  is put back on a list to be
                     called again later, or 1  indicating  either
                     success  in allocating resources or indicat-
                     ing that it no longer cares for a retry.



     The scsidmafree() function frees the DMA resources  associ-
     ated  with  the SCSI packet. The packet itself remains allo-
     cated.

RETURN VALUES
     The scsidmaget() function returns a pointer to  a  scsipkt
     on success. It returns NUL if resources are not available.

CONTEXT
     If callback is SLEPFUNC, then this  routine  may  only  be
     called  from  user  or  kernel context. Otherwise, it may be
     called from user, kernel, or interrupt context. The callback
     function may not block or call routines that block.


     The scsidmafree() function can be called from user,  inter-
     rupt, or kernel context.

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



     
           ATRIBUTE TYPE               ATRIBUTE VALUE       
    
     Stability Level              Obsolete                    
    


SEE ALSO
     attributes(5),     scsipktalloc(9F),      scsipktfree(9F),
     scsiresalloc(9F), scsiresfree(9F), buf(9S), scsipkt(9S)






SunOS 5.11          Last change: 16 Jan 2006                    2






Kernel Functions for Drivers                      scsidmaget(9F)



     Writing Device Drivers

NOTES
     The scsidmaget() and scsidmafree() functions are  obsolete
     and  will  be  discontinued in a future release. These func-
     tions have been replaced by, respectively, scsiinitpkt(9F)
     and scsidestroypkt(9F).
















































SunOS 5.11          Last change: 16 Jan 2006                    3