pci/of: Match PCI devices to OF nodes dynamically

powerpc has two different ways of matching PCI devices to their
corresponding OF node (if any) for historical reasons. The ppc64 one
does a scan looking for matching bus/dev/fn, while the ppc32 one does a
scan looking only for matching dev/fn on each level in order to be
agnostic to busses being renumbered (which Linux does on some
platforms).

This removes both and instead moves the matching code to the PCI core
itself. It's the most logical place to do it: when a pci_dev is created,
we know the parent and thus can do a single level scan for the matching
device_node (if any).

The benefit is that all archs now get the matching for free. There's one
hook the arch might want to provide to match a PHB bus to its device
node. A default weak implementation is provided that looks for the
parent device device node, but it's not entirely reliable on powerpc for
various reasons so powerpc provides its own.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: Michal Simek <monstr@monstr.eu>
Acked-by: Jesse Barnes <jbarnes@virtuousgeek.org>

1 files changed, 61 insertions, 0 deletions

diff --git a/drivers/pci/of.c b/drivers/pci/of.c
new file mode 100644
index 0000000..c94d37e
--- /dev/null
+++ b/drivers/pci/of.c
@@ -0,0 +1,61 @@
+/*
+ * PCI <-> OF mapping helpers
+ *
+ * Copyright 2011 IBM Corp.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/kernel.h>
+#include <linux/pci.h>
+#include <linux/of.h>
+#include <linux/of_pci.h>
+#include "pci.h"
+
+void pci_set_of_node(struct pci_dev *dev)
+{
+	if (!dev->bus->dev.of_node)
+		return;
+	dev->dev.of_node = of_pci_find_child_device(dev->bus->dev.of_node,
+						    dev->devfn);
+}
+
+void pci_release_of_node(struct pci_dev *dev)
+{
+	of_node_put(dev->dev.of_node);
+	dev->dev.of_node = NULL;
+}
+
+void pci_set_bus_of_node(struct pci_bus *bus)
+{
+	if (bus->self == NULL)
+		bus->dev.of_node = pcibios_get_phb_of_node(bus);
+	else
+		bus->dev.of_node = of_node_get(bus->self->dev.of_node);
+}
+
+void pci_release_bus_of_node(struct pci_bus *bus)
+{
+	of_node_put(bus->dev.of_node);
+	bus->dev.of_node = NULL;
+}
+
+struct device_node * __weak pcibios_get_phb_of_node(struct pci_bus *bus)
+{
+	/* This should only be called for PHBs */
+	if (WARN_ON(bus->self || bus->parent))
+		return NULL;
+
+	/* Look for a node pointer in either the intermediary device we
+	 * create above the root bus or it's own parent. Normally only
+	 * the later is populated.
+	 */
+	if (bus->bridge->of_node)
+		return of_node_get(bus->bridge->of_node);
+	if (bus->bridge->parent->of_node)
+		return of_node_get(bus->bridge->parent->of_node);
+	return NULL;
+}