Linux and UNIX Man Pages

Linux & Unix Commands - Search Man Pages

ddi_dma_mem_free(9f) [minix man page]

ddi_dma_mem_free(9F)					   Kernel Functions for Drivers 				      ddi_dma_mem_free(9F)

ddi_dma_mem_free - free previously allocated memory SYNOPSIS
#include <sys/ddi.h> #include <sys/sunddi.h> void ddi_dma_mem_free(ddi_acc_handle_t *handlep); PARAMETERS
handlep Pointer to the data access handle previously allocated by a call to ddi_dma_mem_alloc(9F). INTERFACE LEVEL
Solaris DDI specific (Solaris DDI). DESCRIPTION
ddi_dma_mem_free() deallocates the memory acquired by ddi_dma_mem_alloc(9F). In addition, it destroys the data access handle handlep asso- ciated with the memory. CONTEXT
ddi_dma_mem_free() can be called from user, kernel, or interrupt context. SEE ALSO
ddi_dma_mem_alloc(9F) Writing Device Drivers SunOS 5.10 26 Sep 1994 ddi_dma_mem_free(9F)

Check Out this Related Man Page

ddi_iopb_alloc(9F)					   Kernel Functions for Drivers 					ddi_iopb_alloc(9F)

ddi_iopb_alloc, ddi_iopb_free - allocate and free non-sequentially accessed memory SYNOPSIS
#include <sys/ddi.h> #include <sys/sunddi.h> int ddi_iopb_alloc(dev_info_t *dip, ddi_dma_lim_t *limits, uint_t length, caddr_t *iopbp); void ddi_iopb_free(caddr_t iopb); INTERFACE LEVEL
These interfaces are obsolete. Use ddi_dma_mem_alloc(9F) instead of ddi_iopb_alloc(). Use ddi_dma_mem_free(9F) instead of ddi_iopb_free(). PARAMETERS
ddi_iopb_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. iopbp A pointer to a caddr_t. On a successful return, *iopbp points to the allocated storage. ddi_iopb_free() iopb The iopb returned from a successful call to ddi_iopb_alloc(). DESCRIPTION
ddi_iopb_alloc() allocates memory for DMA transfers and should be used if the device accesses memory in a non-sequential fashion, or if synchronization steps using ddi_dma_sync(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. Note that you still must use DMA resource allocation functions (see ddi_dma_setup(9F)) to establish DMA resources for the memory allocated using ddi_iopb_alloc(). 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 still required. The DMA resources will be allocated so that these synchronization steps are as efficient as possible. ddi_iopb_free() frees up memory allocated by ddi_iopb_alloc(). RETURN VALUES
ddi_iopb_alloc() returns: DDI_SUCCESS Memory successfully allocated. DDI_FAILURE Allocation failed. CONTEXT
These functions can be called from user or 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_mem_alloc(9F), ddi_dma_lim_sparc(9S), ddi_dma_lim_x86(9S), ddi_dma_req(9S) Writing Device Drivers NOTES
This function uses scarce system resources. Use it selectively. SunOS 5.10 27 Sep 2002 ddi_iopb_alloc(9F)
Man Page