SCO OpenServer

getcpages(D3oddi)

getcpages, freecpages -- allocate and free physically contiguous memory

Synopsis

   #include <sys/types.h>
   #include <sys/immu.h>
   
   caddr_t getcpages(int npgs, int flags);
   

   void freecpages(pft_t pfn, int npgs);

Description

The getcpages( ) function allocates physically contiguous memory, aligned on page boundaries. the freecpages( ) function frees this memory when it is no longer needed.

Arguments

npgs

Number of pages to be allocated.

flags

Provide details about the memory allocation. Valid values are:

ANY_MEM: Allocate memory from any range that is available. If necessary, block until memory comes available.
NOSLEEP: Do not block waiting for memory to be available. If the memory cannot be allocated, just return.
SHORTSLEEP: Block only until the vhand daemon has executed once.
DMAABLE: Allocate DMA-able memory (uner 16 MB).
PREFERDMA: Try to allocate DMA-able memory (uner 16 MB), but allocate memory from another region if none is available in this range.
DMAABLE64K: Allocate memory that is DMA-able over the 64K boundary.

pfn

Page frame number as returned by getcpages( ). This is a memory address in the range 0xC0000000 to 0xEFFFFFFF.

Return values

On success, getcpages( ) returns the page frame number for the first page in the allocated memory region.

Usage

Context and synchronization

Initialization context

Hardware applicability

All

Version applicability

oddi: 1, 2, 2mp, 3, 3mp, 4, 4mp, 5, 5mp, 6, 6mp

SVR5 DDI compatibility

getcpages( ) and freecpages( ) are not supported in any DDI version, although they can be used in $interface nonconformant drivers on SCO SVR5 1.0.

DDI 8 drivers use the kmem_alloc_phys(D3) function or the msgscgth(D3str) function (STREAMS only) to allocate memory for DMA operations.

References

kmem_alloc(D3oddi), kmem_zalloc(D3oddi), kmem_free(D3oddi), sptalloc(D3oddi), sptfree(D3oddi), vasbind(D3oddi)

kmem_alloc_phys(D3), physreq(D4)

``Memory allocation'' in HDK Technical Reference