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, 13 insertions, 137 deletions

diff --git a/arch/powerpc/kernel/pci_32.c b/arch/powerpc/kernel/pci_32.c
index bedb370..8658550 100644
--- a/arch/powerpc/kernel/pci_32.c
+++ b/arch/powerpc/kernel/pci_32.c
@@ -167,150 +167,26 @@ pcibios_make_OF_bus_map(void)
 #endif
 }
 
-typedef int (*pci_OF_scan_iterator)(struct device_node* node, void* data);
-
-static struct device_node*
-scan_OF_pci_childs(struct device_node *parent, pci_OF_scan_iterator filter, void* data)
-{
-	struct device_node *node;
-	struct device_node* sub_node;
-
-	for_each_child_of_node(parent, node) {
-		const unsigned int *class_code;
-	
-		if (filter(node, data)) {
-			of_node_put(node);
-			return node;
-		}
-
-		/* For PCI<->PCI bridges or CardBus bridges, we go down
-		 * Note: some OFs create a parent node "multifunc-device" as
-		 * a fake root for all functions of a multi-function device,
-		 * we go down them as well.
-		 */
-		class_code = of_get_property(node, "class-code", NULL);
-		if ((!class_code || ((*class_code >> 8) != PCI_CLASS_BRIDGE_PCI &&
-			(*class_code >> 8) != PCI_CLASS_BRIDGE_CARDBUS)) &&
-			strcmp(node->name, "multifunc-device"))
-			continue;
-		sub_node = scan_OF_pci_childs(node, filter, data);
-		if (sub_node) {
-			of_node_put(node);
-			return sub_node;
-		}
-	}
-	return NULL;
-}
-
-static struct device_node *scan_OF_for_pci_dev(struct device_node *parent,
-					       unsigned int devfn)
-{
-	struct device_node *np, *cnp;
-	const u32 *reg;
-	unsigned int psize;
-
-	for_each_child_of_node(parent, np) {
-		reg = of_get_property(np, "reg", &psize);
-                if (reg && psize >= 4 && ((reg[0] >> 8) & 0xff) == devfn)
-			return np;
-
-		/* Note: some OFs create a parent node "multifunc-device" as
-		 * a fake root for all functions of a multi-function device,
-		 * we go down them as well. */
-                if (!strcmp(np->name, "multifunc-device")) {
-                        cnp = scan_OF_for_pci_dev(np, devfn);
-                        if (cnp)
-                                return cnp;
-                }
-	}
-	return NULL;
-}
-
-
-static struct device_node *scan_OF_for_pci_bus(struct pci_bus *bus)
-{
-	struct device_node *parent, *np;
-
-	/* Are we a root bus ? */
-	if (bus->self == NULL || bus->parent == NULL) {
-		struct pci_controller *hose = pci_bus_to_host(bus);
-		if (hose == NULL)
-			return NULL;
-		return of_node_get(hose->dn);
-	}
-
-	/* not a root bus, we need to get our parent */
-	parent = scan_OF_for_pci_bus(bus->parent);
-	if (parent == NULL)
-		return NULL;
-
-	/* now iterate for children for a match */
-	np = scan_OF_for_pci_dev(parent, bus->self->devfn);
-	of_node_put(parent);
-
-	return np;
-}
-
-/*
- * Scans the OF tree for a device node matching a PCI device
- */
-struct device_node *
-pci_busdev_to_OF_node(struct pci_bus *bus, int devfn)
-{
-	struct device_node *parent, *np;
-
-	pr_debug("pci_busdev_to_OF_node(%d,0x%x)\n", bus->number, devfn);
-	parent = scan_OF_for_pci_bus(bus);
-	if (parent == NULL)
-		return NULL;
-	pr_debug(" parent is %s\n", parent ? parent->full_name : "<NULL>");
-	np = scan_OF_for_pci_dev(parent, devfn);
-	of_node_put(parent);
-	pr_debug(" result is %s\n", np ? np->full_name : "<NULL>");
-
-	/* XXX most callers don't release the returned node
-	 * mostly because ppc64 doesn't increase the refcount,
-	 * we need to fix that.
-	 */
-	return np;
-}
-EXPORT_SYMBOL(pci_busdev_to_OF_node);
-
-struct device_node*
-pci_device_to_OF_node(struct pci_dev *dev)
-{
-	return pci_busdev_to_OF_node(dev->bus, dev->devfn);
-}
-EXPORT_SYMBOL(pci_device_to_OF_node);
-
-static int
-find_OF_pci_device_filter(struct device_node* node, void* data)
-{
-	return ((void *)node == data);
-}
 
 /*
  * Returns the PCI device matching a given OF node
  */
-int
-pci_device_from_OF_node(struct device_node* node, u8* bus, u8* devfn)
+int pci_device_from_OF_node(struct device_node *node, u8 *bus, u8 *devfn)
 {
-	const unsigned int *reg;
-	struct pci_controller* hose;
-	struct pci_dev* dev = NULL;
-	
-	/* Make sure it's really a PCI device */
-	hose = pci_find_hose_for_OF_device(node);
-	if (!hose || !hose->dn)
-		return -ENODEV;
-	if (!scan_OF_pci_childs(hose->dn,
-			find_OF_pci_device_filter, (void *)node))
+	struct pci_dev *dev = NULL;
+	const __be32 *reg;
+	int size;
+
+	/* Check if it might have a chance to be a PCI device */
+	if (!pci_find_hose_for_OF_device(node))
 		return -ENODEV;
-	reg = of_get_property(node, "reg", NULL);
-	if (!reg)
+
+	reg = of_get_property(node, "reg", &size);
+	if (!reg || size < 5 * sizeof(u32))
 		return -ENODEV;
-	*bus = (reg[0] >> 16) & 0xff;
-	*devfn = ((reg[0] >> 8) & 0xff);
+
+	*bus = (be32_to_cpup(&reg[0]) >> 16) & 0xff;
+	*devfn = (be32_to_cpup(&reg[0]) >> 8) & 0xff;
 
 	/* Ok, here we need some tweak. If we have already renumbered
 	 * all busses, we can't rely on the OF bus number any more.