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

1 files changed, 42 insertions, 0 deletions

diff --git a/sys/dev/ofw/openfirm.c b/sys/dev/ofw/openfirm.c
index d63edcebff9d..0760854079c7 100644
--- a/sys/dev/ofw/openfirm.c
+++ b/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,