net: introduce generic switch devices support

The goal of this is to provide a possibility to support various switch
chips. Drivers should implement relevant ndos to do so. Now there is
only one ndo defined:
- for getting physical switch id is in place.

Note that user can use random port netdevice to access the switch.

Signed-off-by: Jiri Pirko <jiri@resnulli.us>
Reviewed-by: Thomas Graf <tgraf@suug.ch>
Acked-by: Andy Gospodarek <gospo@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/Kconfig b/net/Kconfig
index 99815b5..ff9ffc1 100644
--- a/net/Kconfig
+++ b/net/Kconfig
@@ -228,6 +228,7 @@
 source "net/netlink/Kconfig"
 source "net/mpls/Kconfig"
 source "net/hsr/Kconfig"
+source "net/switchdev/Kconfig"
 
 config RPS
 	boolean
diff --git a/net/Makefile b/net/Makefile
index 7ed1970..95fc694 100644
--- a/net/Makefile
+++ b/net/Makefile
@@ -73,3 +73,6 @@
 obj-$(CONFIG_VSOCKETS)	+= vmw_vsock/
 obj-$(CONFIG_NET_MPLS_GSO)	+= mpls/
 obj-$(CONFIG_HSR)		+= hsr/
+ifneq ($(CONFIG_NET_SWITCHDEV),)
+obj-y				+= switchdev/
+endif
diff --git a/net/switchdev/Kconfig b/net/switchdev/Kconfig
new file mode 100644
index 0000000..1557545
--- /dev/null
+++ b/net/switchdev/Kconfig
@@ -0,0 +1,13 @@
+#
+# Configuration for Switch device support
+#
+
+config NET_SWITCHDEV
+	boolean "Switch (and switch-ish) device support (EXPERIMENTAL)"
+	depends on INET
+	---help---
+	  This module provides glue between core networking code and device
+	  drivers in order to support hardware switch chips in very generic
+	  meaning of the word "switch". This include devices supporting L2/L3 but
+	  also various flow offloading chips, including switches embedded into
+	  SR-IOV NICs.
diff --git a/net/switchdev/Makefile b/net/switchdev/Makefile
new file mode 100644
index 0000000..5ed63ed
--- /dev/null
+++ b/net/switchdev/Makefile
@@ -0,0 +1,5 @@
+#
+# Makefile for the Switch device API
+#
+
+obj-$(CONFIG_NET_SWITCHDEV) += switchdev.o
diff --git a/net/switchdev/switchdev.c b/net/switchdev/switchdev.c
new file mode 100644
index 0000000..66973de
--- /dev/null
+++ b/net/switchdev/switchdev.c
@@ -0,0 +1,33 @@
+/*
+ * net/switchdev/switchdev.c - Switch device API
+ * Copyright (c) 2014 Jiri Pirko <jiri@resnulli.us>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <linux/init.h>
+#include <linux/netdevice.h>
+#include <net/switchdev.h>
+
+/**
+ *	netdev_switch_parent_id_get - Get ID of a switch
+ *	@dev: port device
+ *	@psid: switch ID
+ *
+ *	Get ID of a switch this port is part of.
+ */
+int netdev_switch_parent_id_get(struct net_device *dev,
+				struct netdev_phys_item_id *psid)
+{
+	const struct net_device_ops *ops = dev->netdev_ops;
+
+	if (!ops->ndo_switch_parent_id_get)
+		return -EOPNOTSUPP;
+	return ops->ndo_switch_parent_id_get(dev, psid);
+}
+EXPORT_SYMBOL(netdev_switch_parent_id_get);