Add a kernel interface (OF_xref_phandle()) for systems where phandles

used as cross-references in the device tree and phandles as used by the
Open Firmware client interface are in different namespaces. This include
IBM pSeries hardware as well as FDT systems. FDT certainly abuses
ihandles for this purpose and should be modified to use this API
eventually. This changes no behavior on systems where FreeBSD already
worked.

Reviewed by:	marius
Approved by:	re (kib)
MFC after:	2 weeks

sys/dev/ofw/ofw_bus_subr.c

@@ -300,7 +300,7 @@ ofw_bus_search_intrmap(void *intr, int intrsz, void *regs, int physsz,
 	i = imapsz;
 	while (i > 0) {
 		bcopy(mptr + physsz + intrsz, &parent, sizeof(parent));
-		if (OF_searchprop(parent, "#interrupt-cells",
+		if (OF_searchprop(OF_xref_phandle(parent), "#interrupt-cells",
 		    &pintrsz, sizeof(pintrsz)) == -1)
 			pintrsz = 1;	/* default */
 		pintrsz *= sizeof(pcell_t);

sys/dev/ofw/openfirm.c

@@ -386,6 +386,48 @@ OF_package_to_path(phandle_t package, char *buf, size_t len)
 	return (OFW_PACKAGE_TO_PATH(ofw_obj, package, buf, len));
 }
 
+/* Look up effective phandle (see FDT/PAPR spec) */
+static phandle_t
+OF_child_xref_phandle(phandle_t parent, phandle_t xref)
+{
+	phandle_t child, rxref;
+
+	/*
+	 * Recursively descend from parent, looking for a node with a property
+	 * named either "phandle", "ibm,phandle", or "linux,phandle" that
+	 * matches the xref we are looking for.
+	 */
+
+	for (child = OF_child(parent); child != 0; child = OF_peer(child)) {
+		rxref = OF_child_xref_phandle(child, xref);
+		if (rxref != -1)
+			return (rxref);
+
+		if (OF_getprop(child, "phandle", &rxref, sizeof(rxref)) == -1 &&
+		    OF_getprop(child, "ibm,phandle", &rxref,
+		    sizeof(rxref)) == -1 && OF_getprop(child,
+		    "linux,phandle", &rxref, sizeof(rxref)) == -1)
+			continue;
+
+		if (rxref == xref)
+			return (child);
+	}
+
+	return (-1);
+}
+
+phandle_t
+OF_xref_phandle(phandle_t xref)
+{
+	phandle_t node;
+
+	node = OF_child_xref_phandle(OF_peer(0), xref);
+	if (node == -1)
+		return (xref);
+
+	return (node);
+}
+
 /*  Call the method in the scope of a given instance. */
 int
 OF_call_method(const char *method, ihandle_t instance, int nargs, int nreturns,

sys/dev/ofw/openfirm.h

@@ -118,6 +118,14 @@ ssize_t		OF_canon(const char *path, char *buf, size_t len);
 phandle_t	OF_finddevice(const char *path);
 ssize_t		OF_package_to_path(phandle_t node, char *buf, size_t len);
 
+/*
+ * Some OF implementations (IBM, FDT) have a concept of effective phandles
+ * used for device-tree cross-references. Given one of these, returns the
+ * real phandle. If one can't be found (or running on OF implementations
+ * without this property), returns its input.
+ */
+phandle_t	OF_xref_phandle(phandle_t xref);
+
 /* Device I/O functions */
 ihandle_t	OF_open(const char *path);
 void		OF_close(ihandle_t instance);

sys/powerpc/ofw/ofw_pcibus.c

@@ -210,11 +210,12 @@ ofw_pcibus_enum_devtree(device_t dev, u_int domain, u_int busno)
 				icells = 1;
 				OF_getprop(child, "interrupt-parent", &iparent,
 				    sizeof(iparent));
-				OF_getprop(iparent, "#interrupt-cells", &icells,
-				    sizeof(icells));
-
-				if (iparent != 0)
+				if (iparent != 0) {
+					OF_getprop(OF_xref_phandle(iparent),
+					    "#interrupt-cells", &icells,
+					    sizeof(icells));
 					intr[0] = MAP_IRQ(iparent, intr[0]);
+				}
 
 				if (iparent != 0 && icells > 1) {
 					powerpc_config_intr(intr[0],