powerpc: Create pci_controller_ops.window_alignment and shim

Add pci_controller_ops.window_alignment,
shadowing ppc_md.pcibios_window_alignment.
Add a shim, and changes the callsites to use the shim.

Here, we use pci_window_alignment, as pcibios_window_alignment is
already taken.
Signed-off-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/include/asm/pci-bridge.h

@@ -31,6 +31,9 @@ struct pci_controller_ops {
 	/* Called when pci_enable_device() is called. Returns true to
 	 * allow assignment/enabling of the device. */
 	bool		(*enable_device_hook)(struct pci_dev *);
+
+	/* Called during PCI resource reassignment */
+	resource_size_t (*window_alignment)(struct pci_bus *, unsigned long type);
 };
 
 /*
@@ -325,5 +328,23 @@ static inline bool pcibios_enable_device_hook(struct pci_dev *dev)
 	return true;
 }
 
+static inline resource_size_t pci_window_alignment(struct pci_bus *bus,
+						   unsigned long type)
+{
+	struct pci_controller *phb = pci_bus_to_host(bus);
+
+	if (phb->controller_ops.window_alignment)
+		return phb->controller_ops.window_alignment(bus, type);
+	if (ppc_md.pcibios_window_alignment)
+		return ppc_md.pcibios_window_alignment(bus, type);
+
+	/*
+	 * PCI core will figure out the default
+	 * alignment: 4KiB for I/O and 1MiB for
+	 * memory window.
+	 */
+	return 1;
+}
+
 #endif	/* __KERNEL__ */
 #endif	/* _ASM_POWERPC_PCI_BRIDGE_H */

arch/powerpc/kernel/pci-common.c

@@ -109,15 +109,7 @@ void pcibios_free_controller(struct pci_controller *phb)
 resource_size_t pcibios_window_alignment(struct pci_bus *bus,
 					 unsigned long type)
 {
-	if (ppc_md.pcibios_window_alignment)
-		return ppc_md.pcibios_window_alignment(bus, type);
-
-	/*
-	 * PCI core will figure out the default
-	 * alignment: 4KiB for I/O and 1MiB for
-	 * memory window.
-	 */
-	return 1;
+	return pci_window_alignment(bus, type);
 }
 
 void pcibios_reset_secondary_bus(struct pci_dev *dev)