VirtualCopy and VirtualAlloc

Hi,
  This might be a very basic question. But please help me, as I am a
newbie to this field.

I am involved in writing an audio codec (linux) driver which has no
DMA controller of its own, but the coprocessor(MQ1132) which controls
the CODEC has a dma controller. Can I directly address a memory
location (Virtual) through the linux device driver, or should I map it
and then use. Actually the windows code for the same is doing some
VirtualAlloc and VirtualCopy. Do I need to do any such things or can I
directly use the the virtual address directly in my code.

Thanks in advance
Suresh. R