[PATCH 4/8] PCI: endpoint: Add linkdown notifier support

[Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>]

Add support to notify the EPF device about the linkdown event from the
EPC device.

Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
---
 drivers/pci/endpoint/pci-epc-core.c | 17 +++++++++++++++++
 include/linux/pci-epc.h             |  1 +
 include/linux/pci-epf.h             |  1 +
 3 files changed, 19 insertions(+)

diff --git a/drivers/pci/endpoint/pci-epc-core.c b/drivers/pci/endpoint/pci-epc-core.c
index 3bc9273d0a08..8401c2750c9e 100644
--- a/drivers/pci/endpoint/pci-epc-core.c
+++ b/drivers/pci/endpoint/pci-epc-core.c
@@ -697,6 +697,23 @@ void pci_epc_linkup(struct pci_epc *epc)
 }
 EXPORT_SYMBOL_GPL(pci_epc_linkup);
 
+/**
+ * pci_epc_linkdown() - Notify the EPF device that EPC device has dropped the
+ *			connection with the Root Complex.
+ * @epc: the EPC device which has dropped the link with the host
+ *
+ * Invoke to Notify the EPF device that the EPC device has dropped the
+ * connection with the Root Complex.
+ */
+void pci_epc_linkdown(struct pci_epc *epc)
+{
+	if (!epc || IS_ERR(epc))
+		return;
+
+	atomic_notifier_call_chain(&epc->notifier, LINK_DOWN, NULL);
+}
+EXPORT_SYMBOL_GPL(pci_epc_linkdown);
+
 /**
  * pci_epc_init_notify() - Notify the EPF device that EPC device's core
  *			   initialization is completed.
diff --git a/include/linux/pci-epc.h b/include/linux/pci-epc.h
index c414a08bfd67..d346ab9ae061 100644
--- a/include/linux/pci-epc.h
+++ b/include/linux/pci-epc.h
@@ -215,6 +215,7 @@ void pci_epc_destroy(struct pci_epc *epc);
 int pci_epc_add_epf(struct pci_epc *epc, struct pci_epf *epf,
 		    enum pci_epc_interface_type type);
 void pci_epc_linkup(struct pci_epc *epc);
+void pci_epc_linkdown(struct pci_epc *epc);
 void pci_epc_init_notify(struct pci_epc *epc);
 void pci_epc_remove_epf(struct pci_epc *epc, struct pci_epf *epf,
 			enum pci_epc_interface_type type);
diff --git a/include/linux/pci-epf.h b/include/linux/pci-epf.h
index 0c94cc1513bc..b1fcd88d0b1f 100644
--- a/include/linux/pci-epf.h
+++ b/include/linux/pci-epf.h
@@ -20,6 +20,7 @@ enum pci_epc_interface_type;
 enum pci_notify_event {
 	CORE_INIT,
 	LINK_UP,
+	LINK_DOWN,
 };
 
 enum pci_barno {
-- 
2.25.1