opensolaris man page for ddi_mem_free

ddi_mem_alloc(9F)					   Kernel Functions for Drivers 					 ddi_mem_alloc(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, 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()
       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 functions (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  require-
       ments, 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, interrupt, 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 attributes:

       +-----------------------------+-----------------------------+
       |      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

SunOS 5.11							    04 Apr 2006 						 ddi_mem_alloc(9F)