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>

1 files changed, 110 insertions, 0 deletions

diff --git a/net/dsa/dsa_priv.h b/net/dsa/dsa_priv.h
new file mode 100644
index 0000000..21ee905
--- /dev/null
+++ b/net/dsa/dsa_priv.h
@@ -0,0 +1,110 @@
+/*
+ * net/dsa/dsa_priv.h - 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.
+ */
+
+#ifndef __DSA_PRIV_H
+#define __DSA_PRIV_H
+
+#include <linux/list.h>
+#include <linux/phy.h>
+#include <linux/timer.h>
+#include <linux/workqueue.h>
+#include <net/dsa.h>
+
+struct dsa_switch {
+	/*
+	 * Configuration data for the platform device that owns
+	 * this dsa switch instance.
+	 */
+	struct dsa_platform_data	*pd;
+
+	/*
+	 * References to network device and mii bus to use.
+	 */
+	struct net_device		*master_netdev;
+	struct mii_bus			*master_mii_bus;
+
+	/*
+	 * The used switch driver and frame tagging type.
+	 */
+	struct dsa_switch_driver	*drv;
+	__be16				tag_protocol;
+
+	/*
+	 * Slave mii_bus and devices for the individual ports.
+	 */
+	int				cpu_port;
+	u32				valid_port_mask;
+	struct mii_bus			*slave_mii_bus;
+	struct net_device		*ports[DSA_MAX_PORTS];
+
+	/*
+	 * Link state polling.
+	 */
+	struct work_struct		link_poll_work;
+	struct timer_list		link_poll_timer;
+};
+
+struct dsa_slave_priv {
+	struct net_device	*dev;
+	struct dsa_switch	*parent;
+	int			port;
+	struct phy_device	*phy;
+};
+
+struct dsa_switch_driver {
+	struct list_head	list;
+
+	__be16			tag_protocol;
+	int			priv_size;
+
+	/*
+	 * Probing and setup.
+	 */
+	char	*(*probe)(struct mii_bus *bus, int sw_addr);
+	int	(*setup)(struct dsa_switch *ds);
+	int	(*set_addr)(struct dsa_switch *ds, u8 *addr);
+
+	/*
+	 * Access to the switch's PHY registers.
+	 */
+	int	(*phy_read)(struct dsa_switch *ds, int port, int regnum);
+	int	(*phy_write)(struct dsa_switch *ds, int port,
+			     int regnum, u16 val);
+
+	/*
+	 * Link state polling and IRQ handling.
+	 */
+	void	(*poll_link)(struct dsa_switch *ds);
+
+	/*
+	 * ethtool hardware statistics.
+	 */
+	void	(*get_strings)(struct dsa_switch *ds, int port, uint8_t *data);
+	void	(*get_ethtool_stats)(struct dsa_switch *ds,
+				     int port, uint64_t *data);
+	int	(*get_sset_count)(struct dsa_switch *ds);
+};
+
+/* dsa.c */
+extern char dsa_driver_version[];
+void register_switch_driver(struct dsa_switch_driver *type);
+void unregister_switch_driver(struct dsa_switch_driver *type);
+
+/* slave.c */
+void dsa_slave_mii_bus_init(struct dsa_switch *ds);
+struct net_device *dsa_slave_create(struct dsa_switch *ds,
+				    struct device *parent,
+				    int port, char *name);
+
+/* tag_edsa.c */
+int edsa_xmit(struct sk_buff *skb, struct net_device *dev);
+
+
+#endif