Allocating non-cached memory

To allocate memory that will not be cached:

For DDI 8

Allocate the memory with the kmem_alloc_phys(D3) function. Convert the memory address (32 or 64 bits depending on the value of the phys_dmasize member of the physreq(D4) structure) to memory block number and offset, and map the virtual address using the devmem_mapin(D3) function.

For DDI 7.2

Allocate the memory with the kmem_alloc_phys(D3) function. You must populate a physreq(D4) structure, being sure to set the phys_dmasize member to a value less than 32, even if your device is 64-bit capable. Then use the physmap(D3) function to map in the memory. The mapping generated by physmap( ) is not cached.

On SCO OpenServer 5 systems

Allocate the memory with the sptalloc(D3oddi) function, setting the PG_PCD bit in the mode argument. This sets the cache disable bit (pg_cd) in the corresponding page table entry.