powerpc/pci: Move pci_find_bus_by_node() around

This moves pci_find_bus_by_node() from arch/powerpc/platforms/
pseries/pci_dlpar.c to arch/powerpc/kernel/pci-hotplug.c so that
the function can be used by pSeries and PowerNV platform at the
same time. Also, below cleanup applied. No functional changes
introduced.

   * Remove variable "busdn" in find_bus_among_children()
   * Use PCI_DN() to convert device node to pci_dn

Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/kernel/pci-hotplug.c

@@ -21,6 +21,35 @@
 #include <asm/firmware.h>
 #include <asm/eeh.h>
 
+static struct pci_bus *find_bus_among_children(struct pci_bus *bus,
+					       struct device_node *dn)
+{
+	struct pci_bus *child = NULL;
+	struct pci_bus *tmp;
+
+	if (pci_bus_to_OF_node(bus) == dn)
+		return bus;
+
+	list_for_each_entry(tmp, &bus->children, node) {
+		child = find_bus_among_children(tmp, dn);
+		if (child)
+			break;
+	}
+
+	return child;
+}
+
+struct pci_bus *pci_find_bus_by_node(struct device_node *dn)
+{
+	struct pci_dn *pdn = PCI_DN(dn);
+
+	if (!pdn  || !pdn->phb || !pdn->phb->bus)
+		return NULL;
+
+	return find_bus_among_children(pdn->phb->bus, dn);
+}
+EXPORT_SYMBOL_GPL(pci_find_bus_by_node);
+
 /**
  * pcibios_release_device - release PCI device
  * @dev: PCI device

arch/powerpc/platforms/pseries/pci_dlpar.c

@@ -34,37 +34,6 @@
 
 #include "pseries.h"
 
-static struct pci_bus *
-find_bus_among_children(struct pci_bus *bus,
-                        struct device_node *dn)
-{
-	struct pci_bus *child = NULL;
-	struct pci_bus *tmp;
-	struct device_node *busdn;
-
-	busdn = pci_bus_to_OF_node(bus);
-	if (busdn == dn)
-		return bus;
-
-	list_for_each_entry(tmp, &bus->children, node) {
-		child = find_bus_among_children(tmp, dn);
-		if (child)
-			break;
-	};
-	return child;
-}
-
-struct pci_bus *pci_find_bus_by_node(struct device_node *dn)
-{
-	struct pci_dn *pdn = dn->data;
-
-	if (!pdn  || !pdn->phb || !pdn->phb->bus)
-		return NULL;
-
-	return find_bus_among_children(pdn->phb->bus, dn);
-}
-EXPORT_SYMBOL_GPL(pci_find_bus_by_node);
-
 struct pci_controller *init_phb_dynamic(struct device_node *dn)
 {
 	struct pci_controller *phb;