On Tue, Dec 08, 1998 at 12:50:16PM +0530, Sera wrote:

> I am passing a buffer of 2k with some data (from user application) to my
> driver using write system call. This data will be used by the driver for
> busmaster DMA. for that, in the kernel driver  I need the physical
> address of the virtual address sent by the user. How do I get this ?
> (basically from virtual address to physical address)

You need to read the bus_dma(9) man page. For an overview of the concept,
read the paper "A Machine-Independent DMA Framework for NetBSD" by Jason
Thorpe, available from the 'net as

http://www.usenix.org/publications/library/proceedings/usenix98/freenix/thorpe.dma.ps

Regards,
	-is