powerpc/PCI: split PHB part out of pcibios_map_io_space()

No functional change.  This is so we can use pcibios_phb_map_io_space()
before we have a struct pci_bus.

v2: fix map io phb typo

CC: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

arch/powerpc/kernel/pci_64.c

@@ -131,30 +131,13 @@ EXPORT_SYMBOL_GPL(pcibios_unmap_io_space);
 
 #endif /* CONFIG_HOTPLUG */
 
-int __devinit pcibios_map_io_space(struct pci_bus *bus)
+static int __devinit pcibios_map_phb_io_space(struct pci_controller *hose)
 {
 	struct vm_struct *area;
 	unsigned long phys_page;
 	unsigned long size_page;
 	unsigned long io_virt_offset;
-	struct pci_controller *hose;
 
-	WARN_ON(bus == NULL);
-
-	/* If this not a PHB, nothing to do, page tables still exist and
-	 * thus HPTEs will be faulted in when needed
-	 */
-	if (bus->self) {
-		pr_debug("IO mapping for PCI-PCI bridge %s\n",
-			 pci_name(bus->self));
-		pr_debug("  virt=0x%016llx...0x%016llx\n",
-			 bus->resource[0]->start + _IO_BASE,
-			 bus->resource[0]->end + _IO_BASE);
-		return 0;
-	}
-
-	/* Get the host bridge */
-	hose = pci_bus_to_host(bus);
 	phys_page = _ALIGN_DOWN(hose->io_base_phys, PAGE_SIZE);
 	size_page = _ALIGN_UP(hose->pci_io_size, PAGE_SIZE);
 
@@ -198,11 +181,30 @@ int __devinit pcibios_map_io_space(struct pci_bus *bus)
 
 	return 0;
 }
+
+int __devinit pcibios_map_io_space(struct pci_bus *bus)
+{
+	WARN_ON(bus == NULL);
+
+	/* If this not a PHB, nothing to do, page tables still exist and
+	 * thus HPTEs will be faulted in when needed
+	 */
+	if (bus->self) {
+		pr_debug("IO mapping for PCI-PCI bridge %s\n",
+			 pci_name(bus->self));
+		pr_debug("  virt=0x%016llx...0x%016llx\n",
+			 bus->resource[0]->start + _IO_BASE,
+			 bus->resource[0]->end + _IO_BASE);
+		return 0;
+	}
+
+	return pcibios_map_phb_io_space(pci_bus_to_host(bus));
+}
 EXPORT_SYMBOL_GPL(pcibios_map_io_space);
 
 void __devinit pcibios_setup_phb_io_space(struct pci_controller *hose)
 {
-	pcibios_map_io_space(hose->bus);
+	pcibios_map_phb_io_space(hose);
 }
 
 #define IOBASE_BRIDGE_NUMBER	0