Myself, I'd rather have something:

	db = dma_alloc(bus_pointer);	/* ISA, PCI, QBUS,
					   EISA, SBUS, TC, whatever */

	/*
	 * this needs to be a loop in case we cross a page boundary.
	 */
	do {
	    if (!dma_map(db, &va1, &length1, &bus_addr))
		goto cleanup;
	    /* use value of bus_addr; va1 & length1 have been modified 
	     * to either NULL & 0 or the amount in the next page */
	} while (va1 != NULL);

	/*
	 * do it for next virtually discontigous chunk
	 */

	/* do the dma op */

	dma_start(db);		/* for ISA */

	/* much later after dma op has finish */

	dma_free(db);		/* free resources */

ideally, bus_pointer should be the (devirable from) parent pointer from
your probe call since that should be pointing to the instance of the bus.



Matt Thomas               Internet:   matt@lkg.dec.com
3am Software Foundry      WWW URL:    <currently homeless>
Westford, MA              Disclaimer: Digital disavows all knowledge
                                      of this message