ddi_mem_free(9F)

NAME

     ddi_mem_alloc, ddi_mem_free - allocate and free sequentially
     accessed memory

SYNOPSIS

     #include <sys/ddi.h>
     #include <sys/sunddi.h>

     int ddi_mem_alloc(dev_info_t  *dip,  ddi_dma_lim_t  *limits,
     uint_t   length,   uint_t  flags,  caddr_t  *kaddrp,  uint_t
     *real_length);

     void ddi_mem_free(caddr_t kaddr);

INTERFACE LEVEL

     These interfaces  are  obsolete.  ddi_dma_mem_alloc(9F)  and
     ddi_dma_mem_free(9F) should be used instead.

PARAMETERS

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

     limits
           A pointer to a DMA limits structure  for  this  device
           (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.

     flags The possible flags 1 and 0 are taken to mean,  respec-
           tively,  wait  until  memory  is  available, or do not
           wait.

     kaddrp
           On a successful return, *kaddrp points  to  the  allo-
           cated memory.

     real_length
           The length in bytes that was allocated. Alignment  and
           padding  requirements  may  cause  ddi_mem_alloc()  to
           allocate more memory than requested in length.

  ddi_mem_free()
     kaddr The  memory  returned  from  a  successful   call   to
           ddi_mem_alloc().

DESCRIPTION

     ddi_mem_alloc() allocates  memory  for   DMA  transfers  and
     should  be used if the device is performing sequential, uni-
     directional, block-sized and block-aligned transfers  to  or
     from  memory.  This  type  of  access  is  commonly known as
     streaming access. The allocation will obey the alignment and
     padding  constraints as specified by the limits argument and
     other limits imposed by the system.

     Note that you must still use DMA resource  allocation  func-
     tions (see ddi_dma_setup(9F)) to establish DMA resources for
     the memory allocated using ddi_mem_alloc().  ddi_mem_alloc()
     returns  the  actual  size  of  the allocated memory object.
     Because of padding and alignment  requirements,  the  actual
     size   might   be   larger   than   the    requested   size.
     ddi_dma_setup(9F) requires the actual length.

     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
     required.

     ddi_mem_free() frees up memory allocated by ddi_mem_alloc().

RETURN VALUES

     ddi_mem_alloc() returns:

     DDI_SUCCESS
           Memory successfully allocated.

     DDI_FAILURE
           Allocation failed.

CONTEXT

     ddi_mem_alloc() can be called from user  or  interrupt  con-
     text,  except  when  flags is set to 1, in which case it can
     be called from user context only.

ATTRIBUTES

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

     ____________________________________________________________
    |       ATTRIBUTE TYPE        |       ATTRIBUTE VALUE       |
    |_____________________________|_____________________________|
    | Stability Level             | 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_iopb_alloc(9F),                   ddi_dma_lim_sparc(9S),
     ddi_dma_lim_x86(9S), ddi_dma_req(9S)

     Writing Device Drivers