powerpc: add in some busdma domain setup

* Implement the basic tag domain set routine
* Set the domain to the parent domain if provided

This is just plumbing for eventual work to re-allocate things into
the currently configured domain.

Differential Revision:	https://reviews.freebsd.org/D55315

sys/powerpc/include/bus_dma_impl.h

@@ -42,6 +42,7 @@ struct bus_dma_tag_common {
 	int		  flags;
 	bus_dma_lock_t	 *lockfunc;
 	void		 *lockfuncarg;
+	int		  domain;
 };
 
 struct bus_dma_impl {

sys/powerpc/powerpc/busdma_bounce.c

@@ -34,6 +34,7 @@
 #include <sys/systm.h>
 #include <sys/malloc.h>
 #include <sys/bus.h>
+#include <sys/domainset.h>
 #include <sys/interrupt.h>
 #include <sys/kernel.h>
 #include <sys/ktr.h>
@@ -49,6 +50,7 @@
 #include <vm/vm_kern.h>
 #include <vm/vm_page.h>
 #include <vm/vm_map.h>
+#include <vm/vm_phys.h>
 
 #include <machine/atomic.h>
 #include <machine/bus.h>
@@ -80,6 +82,7 @@ static MALLOC_DEFINE(M_BUSDMA, "busdma", "busdma metadata");
 /* XXX TODO: bounce flags? */
 #define	dmat_bounce_flags(dmat)	(0)
 #define	dmat_boundary(dmat)	((dmat)->common.boundary)
+#define	dmat_domain(dmat)	((dmat)->common.domain)
 #define	dmat_flags(dmat)	((dmat)->common.flags)
 #define	dmat_highaddr(dmat)	((dmat)->common.highaddr)
 #define	dmat_lowaddr(dmat)	((dmat)->common.lowaddr)
@@ -219,6 +222,8 @@ bounce_bus_dma_tag_create(bus_dma_tag_t parent, bus_size_t alignment,
 
 		newtag->iommu = parent->iommu;
 		newtag->iommu_cookie = parent->iommu_cookie;
+		newtag->common.domain = vm_phys_domain_match(newtag->common.domain, 0ul,
+		    newtag->common.lowaddr);
 	}
 
 	if (newtag->common.lowaddr < ptoa((vm_paddr_t)Maxmem) && newtag->iommu == NULL)

sys/powerpc/powerpc/busdma_machdep.c

@@ -49,6 +49,7 @@
 #include <vm/vm_kern.h>
 #include <vm/vm_page.h>
 #include <vm/vm_map.h>
+#include <vm/vm_phys.h>
 
 #include <machine/atomic.h>
 #include <machine/bus.h>
@@ -129,6 +130,10 @@ bus_dma_tag_set_domain(bus_dma_tag_t dmat, int domain)
 	struct bus_dma_tag_common *tc;
 
 	tc = (struct bus_dma_tag_common *)dmat;
-
+	domain = vm_phys_domain_match(domain, 0ul, tc->lowaddr);
+	/* Only call the callback if it changes. */
+	if (domain == tc->domain)
+		return (0);
+	tc->domain = domain;
 	return (tc->impl->tag_set_domain(dmat, domain));
 }