net: Distributed Switch Architecture protocol support

Distributed Switch Architecture is a protocol for managing hardware
switch chips.  It consists of a set of MII management registers and
commands to configure the switch, and an ethernet header format to
signal which of the ports of the switch a packet was received from
or is intended to be sent to.

The switches that this driver supports are typically embedded in
access points and routers, and a typical setup with a DSA switch
looks something like this:

	+-----------+       +-----------+
	|           | RGMII |           |
	|           +-------+           +------ 1000baseT MDI ("WAN")
	|           |       |  6-port   +------ 1000baseT MDI ("LAN1")
	|    CPU    |       |  ethernet +------ 1000baseT MDI ("LAN2")
	|           |MIImgmt|  switch   +------ 1000baseT MDI ("LAN3")
	|           +-------+  w/5 PHYs +------ 1000baseT MDI ("LAN4")
	|           |       |           |
	+-----------+       +-----------+

The switch driver presents each port on the switch as a separate
network interface to Linux, polls the switch to maintain software
link state of those ports, forwards MII management interface
accesses to those network interfaces (e.g. as done by ethtool) to
the switch, and exposes the switch's hardware statistics counters
via the appropriate Linux kernel interfaces.

This initial patch supports the MII management interface register
layout of the Marvell 88E6123, 88E6161 and 88E6165 switch chips, and
supports the "Ethertype DSA" packet tagging format.

(There is no officially registered ethertype for the Ethertype DSA
packet format, so we just grab a random one.  The ethertype to use
is programmed into the switch, and the switch driver uses the value
of ETH_P_EDSA for this, so this define can be changed at any time in
the future if the one we chose is allocated to another protocol or
if Ethertype DSA gets its own officially registered ethertype, and
everything will continue to work.)

Signed-off-by: Lennert Buytenhek <buytenh@marvell.com>
Tested-by: Nicolas Pitre <nico@marvell.com>
Tested-by: Byron Bradley <byron.bbradley@gmail.com>
Tested-by: Tim Ellis <tim.ellis@mac.com>
Tested-by: Peter van Valderen <linux@ddcrew.com>
Tested-by: Dirk Teurlings <dirk@upexia.nl>
Signed-off-by: David S. Miller <davem@davemloft.net>

11 files changed, 1893 insertions, 0 deletions

diff --git a/net/Kconfig b/net/Kconfig
index 9103a16a77be..d789d79551ae 100644
--- a/net/Kconfig
+++ b/net/Kconfig
@@ -180,6 +180,7 @@ source "net/tipc/Kconfig"
 source "net/atm/Kconfig"
 source "net/802/Kconfig"
 source "net/bridge/Kconfig"
+source "net/dsa/Kconfig"
 source "net/8021q/Kconfig"
 source "net/decnet/Kconfig"
 source "net/llc/Kconfig"
diff --git a/net/Makefile b/net/Makefile
index acaf819f24aa..27d1f10dc0e0 100644
--- a/net/Makefile
+++ b/net/Makefile
@@ -26,6 +26,7 @@ obj-$(CONFIG_PACKET)		+= packet/
 obj-$(CONFIG_NET_KEY)           += key/
 obj-$(CONFIG_NET_SCHED)         += sched/
 obj-$(CONFIG_BRIDGE)            += bridge/
+obj-$(CONFIG_NET_DSA)           += dsa/
 obj-$(CONFIG_IPX)               += ipx/
 obj-$(CONFIG_ATALK)             += appletalk/
 obj-$(CONFIG_WAN_ROUTER)        += wanrouter/
diff --git a/net/dsa/Kconfig b/net/dsa/Kconfig
new file mode 100644
index 000000000000..7cf55e5eb39f
--- /dev/null
+++ b/net/dsa/Kconfig
@@ -0,0 +1,31 @@
+menuconfig NET_DSA
+        bool "Distributed Switch Architecture support"
+        default n
+        depends on EXPERIMENTAL
+        ---help---
+          This allows you to use hardware switch chips that use
+          the Distributed Switch Architecture.
+
+
+if NET_DSA
+
+# tagging formats
+config NET_DSA_TAG_EDSA
+        bool
+        default n
+
+
+# switch drivers
+config NET_DSA_MV88E6XXX
+        bool
+        default n
+
+config NET_DSA_MV88E6123_61_65
+        bool "Marvell 88E6123/6161/6165 ethernet switch chip support"
+        select NET_DSA_MV88E6XXX
+        select NET_DSA_TAG_EDSA
+        ---help---
+          This enables support for the Marvell 88E6123/6161/6165
+          ethernet switch chips.
+
+endif
diff --git a/net/dsa/Makefile b/net/dsa/Makefile
new file mode 100644
index 000000000000..b59a6f6bcf56
--- /dev/null
+++ b/net/dsa/Makefile
@@ -0,0 +1,9 @@
+# tagging formats
+obj-$(CONFIG_NET_DSA_TAG_EDSA) += tag_edsa.o
+
+# switch drivers
+obj-$(CONFIG_NET_DSA_MV88E6XXX) += mv88e6xxx.o
+obj-$(CONFIG_NET_DSA_MV88E6123_61_65) += mv88e6123_61_65.o
+
+# the core
+obj-$(CONFIG_NET_DSA) += dsa.o slave.o
diff --git a/net/dsa/dsa.c b/net/dsa/dsa.c
new file mode 100644
index 000000000000..6cc5be2ec7f1
--- /dev/null
+++ b/net/dsa/dsa.c
@@ -0,0 +1,369 @@
+/*
+ * net/dsa/dsa.c - Hardware switch handling
+ * Copyright (c) 2008 Marvell Semiconductor
+ *
+ * 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/list.h>
+#include <linux/netdevice.h>
+#include <linux/platform_device.h>
+#include <net/dsa.h>
+#include "dsa_priv.h"
+
+char dsa_driver_version[] = "0.1";
+
+
+/* switch driver registration ***********************************************/
+static DEFINE_MUTEX(dsa_switch_drivers_mutex);
+static LIST_HEAD(dsa_switch_drivers);
+
+void register_switch_driver(struct dsa_switch_driver *drv)
+{
+        mutex_lock(&dsa_switch_drivers_mutex);
+        list_add_tail(&drv->list, &dsa_switch_drivers);
+        mutex_unlock(&dsa_switch_drivers_mutex);
+}
+
+void unregister_switch_driver(struct dsa_switch_driver *drv)
+{
+        mutex_lock(&dsa_switch_drivers_mutex);
+        list_del_init(&drv->list);
+        mutex_unlock(&dsa_switch_drivers_mutex);
+}
+
+static struct dsa_switch_driver *
+dsa_switch_probe(struct mii_bus *bus, int sw_addr, char **_name)
+{
+        struct dsa_switch_driver *ret;
+        struct list_head *list;
+        char *name;
+
+        ret = NULL;
+        name = NULL;
+
+        mutex_lock(&dsa_switch_drivers_mutex);
+        list_for_each(list, &dsa_switch_drivers) {
+                struct dsa_switch_driver *drv;
+
+                drv = list_entry(list, struct dsa_switch_driver, list);
+
+                name = drv->probe(bus, sw_addr);
+                if (name != NULL) {
+                        ret = drv;
+                        break;
+                }
+        }
+        mutex_unlock(&dsa_switch_drivers_mutex);
+
+        *_name = name;
+
+        return ret;
+}
+
+
+/* basic switch operations **************************************************/
+static struct dsa_switch *
+dsa_switch_setup(struct device *parent, struct dsa_platform_data *pd,
+                 struct mii_bus *bus, struct net_device *dev)
+{
+        struct dsa_switch *ds;
+        int ret;
+        struct dsa_switch_driver *drv;
+        char *name;
+        int i;
+
+        /*
+         * Probe for switch model.
+         */
+        drv = dsa_switch_probe(bus, pd->sw_addr, &name);
+        if (drv == NULL) {
+                printk(KERN_ERR "%s: could not detect attached switch\n",
+                       dev->name);
+                return ERR_PTR(-EINVAL);
+        }
+        printk(KERN_INFO "%s: detected a %s switch\n", dev->name, name);
+
+
+        /*
+         * Allocate and initialise switch state.
+         */
+        ds = kzalloc(sizeof(*ds) + drv->priv_size, GFP_KERNEL);
+        if (ds == NULL)
+                return ERR_PTR(-ENOMEM);
+
+        ds->pd = pd;
+        ds->master_netdev = dev;
+        ds->master_mii_bus = bus;
+
+        ds->drv = drv;
+        ds->tag_protocol = drv->tag_protocol;
+
+
+        /*
+         * Validate supplied switch configuration.
+         */
+        ds->cpu_port = -1;
+        for (i = 0; i < DSA_MAX_PORTS; i++) {
+                char *name;
+
+                name = pd->port_names[i];
+                if (name == NULL)
+                        continue;
+
+                if (!strcmp(name, "cpu")) {
+                        if (ds->cpu_port != -1) {