[patch net-next v3 04/17] net: introduce generic switch devices support

Jiri Pirko
2014-11-25T10:28:56Z

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>
---
v2->v3:
-fixed documentation typo pointed out by M. Braun
-changed "sw" string to "switch" to avoid confusion
v1->v2:
-no change
---
Documentation/networking/switchdev.txt | 59 ++++++++++++++++++++++++++++++++++
MAINTAINERS | 7 ++++
include/linux/netdevice.h | 10 ++++++
include/net/switchdev.h | 30 +++++++++++++++++
net/Kconfig | 1 +
net/Makefile | 3 ++
net/switchdev/Kconfig | 13 ++++++++
net/switchdev/Makefile | 5 +++
net/switchdev/switchdev.c | 33 +++++++++++++++++++
9 files changed, 161 insertions(+)
create mode 100644 Documentation/networking/switchdev.txt
create mode 100644 include/net/switchdev.h
create mode 100644 net/switchdev/Kconfig
create mode 100644 net/switchdev/Makefile
create mode 100644 net/switchdev/switchdev.c

diff --git a/Documentation/networking/switchdev.txt b/Documentation/networking/switchdev.txt
new file mode 100644
index 0000000..f981a92
--- /dev/null
+++ b/Documentation/networking/switchdev.txt
@@ -0,0 +1,59 @@
+Switch (and switch-ish) device drivers HOWTO
+===========================
+
+Please note that the word "switch" is here used in very generic meaning.
+This include devices supporting L2/L3 but also various flow offloading chips,
+including switches embedded into SR-IOV NICs.
+
+Lets describe a topology a bit. Imagine the following example:
+
+ +----------------------------+ +---------------+
+ | SOME switch chip | | CPU |
+ +----------------------------+ +---------------+
+ port1 port2 port3 port4 MNGMNT | PCI-E |
+ | | | | | +---------------+
+ PHY PHY | | | | NIC0 NIC1
+ | | | | | |
+ | | +- PCI-E -+ | |
+ | +------- MII -------+ |
+ +------------- MII ------------+
+
+In this example, there are two independent lines between the switch silicon
+and CPU. NIC0 and NIC1 drivers are not aware of a switch presence. They are
+separate from the switch driver. SOME switch chip is by managed by a driver
+via PCI-E device MNGMNT. Note that MNGMNT device, NIC0 and NIC1 may be
+connected to some other type of bus.
+
+Now, for the previous example show the representation in kernel:
+
+ +----------------------------+ +---------------+
+ | SOME switch chip | | CPU |
+ +----------------------------+ +---------------+
+ sw0p0 sw0p1 sw0p2 sw0p3 MNGMNT | PCI-E |
+ | | | | | +---------------+
+ PHY PHY | | | | eth0 eth1
+ | | | | | |
+ | | +- PCI-E -+ | |
+ | +------- MII -------+ |
+ +------------- MII ------------+
+
+Lets call the example switch driver for SOME switch chip "SOMEswitch". This
+driver takes care of PCI-E device MNGMNT. There is a netdevice instance sw0pX
+created for each port of a switch. These netdevices are instances
+of "SOMEswitch" driver. sw0pX netdevices serve as a "representation"
+of the switch chip. eth0 and eth1 are instances of some other existing driver.
+
+The only difference of the switch-port netdevice from the ordinary netdevice
+is that is implements couple more NDOs:
+
+ ndo_switch_parent_id_get - This returns the same ID for two port netdevices
+ of the same physical switch chip. This is
+ mandatory to be implemented by all switch drivers
+ and serves the caller for recognition of a port
+ netdevice.
+ ndo_switch_parent_* - Functions that serve for a manipulation of the switch
+ chip itself (it can be though of as a "parent" of the
+ port, therefore the name). They are not port-specific.
+ Caller might use arbitrary port netdevice of the same
+ switch and it will make no difference.
+ ndo_switch_port_* - Functions that serve for a port-specific manipulation.
diff --git a/MAINTAINERS b/MAINTAINERS
index a545d68..05addb6 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -9058,6 +9058,13 @@ F: lib/swiotlb.c
F: arch/*/kernel/pci-swiotlb.c
F: include/linux/swiotlb.h

+SWITCHDEV
+M: Jiri Pirko <jiri@resnulli.us>
+L: netdev@vger.kernel.org
+S: Supported
+F: net/switchdev/
+F: include/net/switchdev.h
+
SYNOPSYS ARC ARCHITECTURE
M: Vineet Gupta <vgupta@synopsys.com>
S: Supported
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 5b491b3..ce096dc 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -1018,6 +1018,12 @@ typedef u16 (*select_queue_fallback_t)(struct net_device *dev,
* performing GSO on a packet. The device returns true if it is
* able to GSO the packet, false otherwise. If the return value is
* false the stack will do software GSO.
+ *
+ * int (*ndo_switch_parent_id_get)(struct net_device *dev,
+ * struct netdev_phys_item_id *psid);
+ * Called to get an ID of the switch chip this port is part of.
+ * If driver implements this, it indicates that it represents a port
+ * of a switch chip.
*/
struct net_device_ops {
int (*ndo_init)(struct net_device *dev);
@@ -1171,6 +1177,10 @@ struct net_device_ops {
int (*ndo_get_lock_subclass)(struct net_device *dev);
bool (*ndo_gso_check) (struct sk_buff *skb,
struct net_device *dev);
+#ifdef CONFIG_NET_SWITCHDEV
+ int (*ndo_switch_parent_id_get)(struct net_device *dev,
+ struct netdev_phys_item_id *psid);
+#endif
};

/**
diff --git a/include/net/switchdev.h b/include/net/switchdev.h
new file mode 100644
index 0000000..7a52360
--- /dev/null
+++ b/include/net/switchdev.h
@@ -0,0 +1,30 @@
+/*
+ * include/net/switchdev.h - 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.
+ */
+#ifndef _LINUX_SWITCHDEV_H_
+#define _LINUX_SWITCHDEV_H_
+
+#include <linux/netdevice.h>
+
+#ifdef CONFIG_NET_SWITCHDEV
+
+int netdev_switch_parent_id_get(struct net_device *dev,
+ struct netdev_phys_item_id *psid);
+
+#else
+
+static inline int netdev_switch_parent_id_get(struct net_device *dev,
+ struct netdev_phys_item_id *psid)
+{
+ return -EOPNOTSUPP;
+}
+
+#endif
+
+#endif /* _LINUX_SWITCHDEV_H_ */
diff --git a/net/Kconfig b/net/Kconfig
index 99815b5..ff9ffc1 100644
--- a/net/Kconfig
+++ b/net/Kconfig
@@ -228,6 +228,7 @@ source "net/vmw_vsock/Kconfig"
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-$(CONFIG_OPENVSWITCH) += openvswitch/
obj-$(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);
--
1.9.3