PCI: endpoint: Introduce configfs entry for configuring EP functions

Introduce a new configfs entry to configure the EP function (like
configuring the standard configuration header entries) and to bind the EP
function with EP controller.
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

drivers/pci/endpoint/Kconfig

@@ -17,4 +17,13 @@ config PCI_ENDPOINT
 
 	   If in doubt, say "N" to disable Endpoint support.
 
+config PCI_ENDPOINT_CONFIGFS
+	bool "PCI Endpoint Configfs Support"
+	depends on PCI_ENDPOINT
+	select CONFIGFS_FS
+	help
+	   This will enable the configfs entry that can be used to
+	   configure the endpoint function and used to bind the
+	   function with a endpoint controller.
+
 endmenu

drivers/pci/endpoint/Makefile

@@ -2,5 +2,6 @@
 # Makefile for PCI Endpoint Support
 #
 
+obj-$(CONFIG_PCI_ENDPOINT_CONFIGFS)	+= pci-ep-cfs.o
 obj-$(CONFIG_PCI_ENDPOINT)		+= pci-epc-core.o pci-epf-core.o\
 					   pci-epc-mem.o

include/linux/pci-ep-cfs.h

+/**
+ * PCI Endpoint ConfigFS header file
+ *
+ * Copyright (C) 2017 Texas Instruments
+ * Author: Kishon Vijay Abraham I <kishon@ti.com>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 of
+ * the License as published by the Free Software Foundation.
+ */
+
+#ifndef __LINUX_PCI_EP_CFS_H
+#define __LINUX_PCI_EP_CFS_H
+
+#include <linux/configfs.h>
+
+#ifdef CONFIG_PCI_ENDPOINT_CONFIGFS
+struct config_group *pci_ep_cfs_add_epc_group(const char *name);
+void pci_ep_cfs_remove_epc_group(struct config_group *group);
+struct config_group *pci_ep_cfs_add_epf_group(const char *name);
+void pci_ep_cfs_remove_epf_group(struct config_group *group);
+#else
+static inline struct config_group *pci_ep_cfs_add_epc_group(const char *name)
+{
+	return 0;
+}
+
+static inline void pci_ep_cfs_remove_epc_group(struct config_group *group)
+{
+}
+
+static inline struct config_group *pci_ep_cfs_add_epf_group(const char *name)
+{
+	return 0;
+}
+
+static inline void pci_ep_cfs_remove_epf_group(struct config_group *group)
+{
+}
+#endif
+#endif /* __LINUX_PCI_EP_CFS_H */