Manual Pages for UNIX Operating System command usage for man ddi_mem_free

Kernel Functions for Drivers                    ddi_mem_alloc(9F)



NAME
     ddi_mem_alloc, ddi_mem_free - allocate and free sequentially
     accessed memory

SYNOPSIS
     #include 
     #include 

     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  alloca-
                    tion.


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


     kaddrp         On a successful return, *kaddrp points to the
                    allocated 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()




SunOS 5.11          Last change: 04 Apr 2006                    1






Kernel Functions for Drivers                    ddi_mem_alloc(9F)



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


DESCRIPTION
     The  ddi_mem_alloc()  function  allocates  memory  for   DMA
     transfers  and  should  be  used if the device is performing
     sequential, unidirectional,  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.


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

RETURN VALUES
     The ddi_mem_alloc() function returns:

     DDI_SUCCESS    Memory successfully allocated.


     DDI_FAILURE    Allocation failed.


CONTEXT
     The ddi_mem_alloc() function can be called from user, inter-
     rupt,  or  kernel context, except when flags is set to 1, in
     which case it cannot be called from interrupt context.

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






SunOS 5.11          Last change: 04 Apr 2006                    2






Kernel Functions for Drivers                    ddi_mem_alloc(9F)



     ____________________________________________________________
    |       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_iopb_alloc(9F),                   ddi_dma_lim_sparc(9S),
     ddi_dma_lim_x86(9S), ddi_dma_req(9S)


     Writing Device Drivers








































SunOS 5.11          Last change: 04 Apr 2006                    3