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>

4 files changed, 23 insertions, 194 deletions

diff --git a/arch/powerpc/kernel/pci-common.c b/arch/powerpc/kernel/pci-common.c
index 893af2a9cd03..a3c92770e422 100644
--- a/arch/powerpc/kernel/pci-common.c
+++ b/arch/powerpc/kernel/pci-common.c
@@ -1097,9 +1097,6 @@ void __devinit pcibios_setup_bus_devices(struct pci_bus *bus)
 		if (dev->is_added)
 			continue;
 
-		/* Setup OF node pointer in the device */
-		dev->dev.of_node = pci_device_to_OF_node(dev);
-
 		/* Fixup NUMA node as it may not be setup yet by the generic
 		 * code and is needed by the DMA init
 		 */
@@ -1685,6 +1682,13 @@ int early_find_capability(struct pci_controller *hose, int bus, int devfn,
 	return pci_bus_find_capability(fake_pci_bus(hose, bus), devfn, cap);
 }
 
+struct device_node *pcibios_get_phb_of_node(struct pci_bus *bus)
+{
+	struct pci_controller *hose = bus->sysdata;
+
+	return of_node_get(hose->dn);
+}
+
 /**
  * pci_scan_phb - Given a pci_controller, setup and scan the PCI bus
  * @hose: Pointer to the PCI host controller instance structure
@@ -1705,7 +1709,6 @@ void __devinit pcibios_scan_phb(struct pci_controller *hose)
 			hose->global_number);
 		return;
 	}
-	bus->dev.of_node = of_node_get(node);
 	bus->secondary = hose->first_busno;
 	hose->bus = bus;
 
diff --git a/arch/powerpc/kernel/pci_32.c b/arch/powerpc/kernel/pci_32.c
index bedb370459f2..86585508e9c1 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.
diff --git a/arch/powerpc/kernel/pci_dn.c b/arch/powerpc/kernel/pci_dn.c
index 6baabc13306a..478f8d78716b 100644
--- a/arch/powerpc/kernel/pci_dn.c
+++ b/arch/powerpc/kernel/pci_dn.c
@@ -142,53 +142,6 @@ void __devinit pci_devs_phb_init_dynamic(struct pci_controller *phb)
 	traverse_pci_devices(dn, update_dn_pci_info, phb);
 }
 
-/*
- * Traversal func that looks for a <busno,devfcn> value.
- * If found, the pci_dn is returned (thus terminating the traversal).
- */
-static void *is_devfn_node(struct device_node *dn, void *data)
-{
-	int busno = ((unsigned long)data >> 8) & 0xff;
-	int devfn = ((unsigned long)data) & 0xff;
-	struct pci_dn *pci = dn->data;
-
-	if (pci && (devfn == pci->devfn) && (busno == pci->busno))
-		return dn;
-	return NULL;
-}
-
-/*
- * This is the "slow" path for looking up a device_node from a
- * pci_dev.  It will hunt for the device under its parent's
- * phb and then update of_node pointer.
- *
- * It may also do fixups on the actual device since this happens
- * on the first read/write.
- *
- * Note that it also must deal with devices that don't exist.
- * In this case it may probe for real hardware ("just in case")
- * and add a device_node to the device tree if necessary.
- *
- * Is this function necessary anymore now that dev->dev.of_node is
- * used to store the node pointer?
- *
- */
-struct device_node *fetch_dev_dn(struct pci_dev *dev)
-{
-	struct pci_controller *phb = dev->sysdata;
-	struct device_node *dn;
-	unsigned long searchval = (dev->bus->number << 8) | dev->devfn;
-
-	if (WARN_ON(!phb))
-		return NULL;
-
-	dn = traverse_pci_devices(phb->dn, is_devfn_node, (void *)searchval);
-	if (dn)
-		dev->dev.of_node = dn;
-	return dn;
-}
-EXPORT_SYMBOL(fetch_dev_dn);
-
 /** 
  * pci_devs_phb_init - Initialize phbs and pci devs under them.
  * 
diff --git a/arch/powerpc/kernel/pci_of_scan.c b/arch/powerpc/kernel/pci_of_scan.c
index 1e89a72fd030..fe0a5ad6f73e 100644
--- a/arch/powerpc/kernel/pci_of_scan.c
+++ b/arch/powerpc/kernel/pci_of_scan.c
@@ -202,9 +202,9 @@ EXPORT_SYMBOL(of_create_pci_dev);
  * this routine in turn call of_scan_bus() recusively to scan for more child
  * devices.
  */
-void __devinit of_scan_pci_bridge(struct device_node *node,
-				  struct pci_dev *dev)
+void __devinit of_scan_pci_bridge(struct pci_dev *dev)
 {
+	struct device_node *node = dev->dev.of_node;
 	struct pci_bus *bus;
 	const u32 *busrange, *ranges;
 	int len, i, mode;
@@ -238,7 +238,6 @@ void __devinit of_scan_pci_bridge(struct device_node *node,
 	bus->primary = dev->bus->number;
 	bus->subordinate = busrange[1];
 	bus->bridge_ctl = 0;
-	bus->dev.of_node = of_node_get(node);
 
 	/* parse ranges property */
 	/* PCI #address-cells == 3 and #size-cells == 2 always */
@@ -335,9 +334,7 @@ static void __devinit __of_scan_bus(struct device_node *node,
 	list_for_each_entry(dev, &bus->devices, bus_list) {
 		if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE ||
 		    dev->hdr_type == PCI_HEADER_TYPE_CARDBUS) {
-			struct device_node *child = pci_device_to_OF_node(dev);
-			if (child)
-				of_scan_pci_bridge(child, dev);
+			of_scan_pci_bridge(dev);
 		}
 	}
 }