[src/trunk]: src/sys/dev/fdt When searching for interrupt parent, stop as soo...

[jmcneill <jmcneill%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/b16a87f4bb01
branches:  trunk
changeset: 833596:b16a87f4bb01
user:      jmcneill <jmcneill%NetBSD.org@localhost>
date:      Mon Jul 02 17:50:02 2018 +0000

description:
When searching for interrupt parent, stop as soon as we see an
interrupt-controller property on a node other than the starting node.

diffstat:

 sys/dev/fdt/fdt_intr.c |  34 +++++++++++++++++++++++++++++-----
 1 files changed, 29 insertions(+), 5 deletions(-)

diffs (64 lines):

diff -r 42027620d48c -r b16a87f4bb01 sys/dev/fdt/fdt_intr.c
--- a/sys/dev/fdt/fdt_intr.c    Mon Jul 02 17:13:15 2018 +0000
+++ b/sys/dev/fdt/fdt_intr.c    Mon Jul 02 17:50:02 2018 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: fdt_intr.c,v 1.14 2018/07/02 16:06:50 jmcneill Exp $ */
+/* $NetBSD: fdt_intr.c,v 1.15 2018/07/02 17:50:02 jmcneill Exp $ */
 
 /*-
  * Copyright (c) 2015-2018 Jared McNeill <jmcneill%invisible.ca@localhost>
@@ -27,7 +27,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: fdt_intr.c,v 1.14 2018/07/02 16:06:50 jmcneill Exp $");
+__KERNEL_RCSID(0, "$NetBSD: fdt_intr.c,v 1.15 2018/07/02 17:50:02 jmcneill Exp $");
 
 #include <sys/param.h>
 #include <sys/bus.h>
@@ -56,18 +56,42 @@
 static u_int * get_specifier_by_index(int, int, int *);
 static u_int * get_specifier_from_map(int, const u_int *, int *);
 
+/*
+ * Find the interrupt controller for a given node. This function will either
+ * return the phandle of the interrupt controller for this node, or the phandle
+ * of a node containing an interrupt-map table that can be used to find the
+ * real interrupt controller.
+ */
 static int
 fdtbus_get_interrupt_parent(int phandle)
 {
        int iparent = phandle;
 
        do {
+               /*
+                * If the node is an interrupt-controller, we are done. Note that
+                * a node cannot be an interrupt-controller for itself, so we skip
+                * the leaf node here.
+                */
+               if (phandle != iparent && of_hasprop(iparent, "interrupt-controller"))
+                       return iparent;
+
+               /*
+                * If the node has an explicit interrupt-parent, follow the reference.
+                */
                if (of_hasprop(iparent, "interrupt-parent"))
                        return fdtbus_get_phandle(iparent, "interrupt-parent");
-               else if (of_hasprop(iparent, "interrupt-controller"))
+
+               /*
+                * If the node has an interrupt-map, use it. The caller is responsible
+                * for parsing the interrupt-map and finding the real interrupt parent.
+                */
+               if (of_hasprop(iparent, "interrupt-map"))
                        return iparent;
-               else if (of_hasprop(iparent, "interrupt-map"))
-                       return iparent;
+
+               /*
+                * Continue searching up the tree.
+                */
                iparent = OF_parent(iparent);
        } while (iparent > 0);