powerpc/pci: Introduce pci_remove_device_node_info()

This implements and exports pci_remove_device_node_info(). It's
used to remove the pdn (struct pci_dn) for the indicated device
node. The function is going to be used by PowerNV PCI hotplug
driver.

Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

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

@@ -237,6 +237,7 @@ extern struct pci_dn *add_dev_pci_data(struct pci_dev *pdev);
 extern void remove_dev_pci_data(struct pci_dev *pdev);
 extern struct pci_dn *pci_add_device_node_info(struct pci_controller *hose,
 					       struct device_node *dn);
+extern void pci_remove_device_node_info(struct device_node *dn);
 
 static inline int pci_device_from_OF_node(struct device_node *np,
 					  u8 *bus, u8 *devfn)

arch/powerpc/kernel/pci_dn.c

@@ -331,6 +331,29 @@ struct pci_dn *pci_add_device_node_info(struct pci_controller *hose,
 }
 EXPORT_SYMBOL_GPL(pci_add_device_node_info);
 
+void pci_remove_device_node_info(struct device_node *dn)
+{
+	struct pci_dn *pdn = dn ? PCI_DN(dn) : NULL;
+#ifdef CONFIG_EEH
+	struct eeh_dev *edev = pdn_to_eeh_dev(pdn);
+
+	if (edev)
+		edev->pdn = NULL;
+#endif
+
+	if (!pdn)
+		return;
+
+	WARN_ON(!list_empty(&pdn->child_list));
+	list_del(&pdn->list);
+	if (pdn->parent)
+		of_node_put(pdn->parent->node);
+
+	dn->data = NULL;
+	kfree(pdn);
+}
+EXPORT_SYMBOL_GPL(pci_remove_device_node_info);
+
 /*
  * Traverse a device tree stopping each PCI device in the tree.
  * This is done depth first.  As each node is processed, a "pre"