PCI: Make resetting secondary bus logic common

Commit d92a208d ("powerpc/pci: Mask linkDown on resetting PCI bus")
implemented same logic (resetting PCI secondary bus by bridge's config
register PCI_BRIDGE_CTL_BUS_RESET) in PCI core and arch-dependent code.  To
avoid the duplication, move the logic to pci_reset_secondary_bus().

That commit did not declare the pcibios_reset_secondary_bus() interface in
linux/include/pci.h.  Add the declaration.

No functional change.
Signed-off-by: NGavin Shan <gwshan@linux.vnet.ibm.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

drivers/pci/pci.c

@@ -3193,7 +3193,7 @@ static int pci_pm_reset(struct pci_dev *dev, int probe)
 	return 0;
 }
 
-void __weak pcibios_reset_secondary_bus(struct pci_dev *dev)
+void pci_reset_secondary_bus(struct pci_dev *dev)
 {
 	u16 ctrl;
 
@@ -3219,6 +3219,11 @@ void __weak pcibios_reset_secondary_bus(struct pci_dev *dev)
 	ssleep(1);
 }
 
+void __weak pcibios_reset_secondary_bus(struct pci_dev *dev)
+{
+	pci_reset_secondary_bus(dev);
+}
+
 /**
  * pci_reset_bridge_secondary_bus - Reset the secondary bus on a PCI bridge.
  * @dev: Bridge device

include/linux/pci.h

@@ -978,6 +978,8 @@ int pci_try_reset_slot(struct pci_slot *slot);
 int pci_probe_reset_bus(struct pci_bus *bus);
 int pci_reset_bus(struct pci_bus *bus);
 int pci_try_reset_bus(struct pci_bus *bus);
+void pci_reset_secondary_bus(struct pci_dev *dev);
+void pcibios_reset_secondary_bus(struct pci_dev *dev);
 void pci_reset_bridge_secondary_bus(struct pci_dev *dev);
 void pci_update_resource(struct pci_dev *dev, int resno);
 int __must_check pci_assign_resource(struct pci_dev *dev, int i);