>>>>> "JT" == Jason Thorpe <thorpej@nas.nasa.gov> writes:

JT> NAS $Id: busdma.doc,v 1.19 1996/11/09 01:41:35 thorpej Exp $

JT> 	bus_dmamap_load_func_t	A driver-dependent function used to load
JT> 				a device's scatter-gather descriptors.
JT> 				The type of the function should be:

JT> 		typedef	int (*bus_dmamap_load_func_t) __P((bus_addr_t addr,
JT> 		    bus_size_t size, void *arg));

JT> 				This function will be called iteratively
JT> 				by bus_dmamap_load() with the address
JT> 				and length of a single, contiguous DMA
JT> 				transfer, conforming to the constraints
JT> 				of the device.  "arg" is a driver-dependent
JT> 				cookie used by the driver to keep state
JT> 				between iterations.

I think you need to pass wait/nowait flags here too--if
bus_dmamap_load() will be calling this function, it has to be able to
tell whether it's safe to wait (as specified in the bus_dmamap_create()
call).  (Either that, or specify that it must never wait.)

==John