Sparc DMA driver example

Can anyone suggest driver source code (or documenation) that would be helpful 
in writing a driver that uses DMA on a Sparc (Ultra 10, etc.) ?

I am trying to find a overview of the operations required on the various 
types of memory accessable from the driver.

Is it possible to resolve a user virtual address to a physical address, lock 
that physical address, perform DMA between the device and the locked physcial 
address and then unlock the physical memory ?

Thanks,

Murray Atkinson.