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, 288 insertions, 0 deletions

diff --git a/net/dsa/slave.c b/net/dsa/slave.c
new file mode 100644
index 000000000000..3cb331e98b89
--- /dev/null
+++ b/net/dsa/slave.c
@@ -0,0 +1,288 @@
+/*
+ * net/dsa/slave.c - Slave device 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/phy.h>
+#include "dsa_priv.h"
+
+/* slave mii_bus handling ***************************************************/
+static int dsa_slave_phy_read(struct mii_bus *bus, int addr, int reg)
+{
+        struct dsa_switch *ds = bus->priv;
+
+        if (ds->valid_port_mask & (1 << addr))
+                return ds->drv->phy_read(ds, addr, reg);
+
+        return 0xffff;
+}
+
+static int dsa_slave_phy_write(struct mii_bus *bus, int addr, int reg, u16 val)
+{
+        struct dsa_switch *ds = bus->priv;
+
+        if (ds->valid_port_mask & (1 << addr))
+                return ds->drv->phy_write(ds, addr, reg, val);
+
+        return 0;
+}
+
+void dsa_slave_mii_bus_init(struct dsa_switch *ds)
+{
+        ds->slave_mii_bus->priv = (void *)ds;
+        ds->slave_mii_bus->name = "dsa slave smi";
+        ds->slave_mii_bus->read = dsa_slave_phy_read;
+        ds->slave_mii_bus->write = dsa_slave_phy_write;
+        snprintf(ds->slave_mii_bus->id, MII_BUS_ID_SIZE, "%s:%.2x",
+                        ds->master_mii_bus->id, ds->pd->sw_addr);
+        ds->slave_mii_bus->parent = &(ds->master_mii_bus->dev);
+}
+
+
+/* slave device handling ****************************************************/
+static int dsa_slave_open(struct net_device *dev)
+{
+        return 0;
+}
+
+static int dsa_slave_close(struct net_device *dev)
+{
+        return 0;
+}
+
+static void dsa_slave_change_rx_flags(struct net_device *dev, int change)
+{
+        struct dsa_slave_priv *p = netdev_priv(dev);
+        struct net_device *master = p->parent->master_netdev;
+
+        if (change & IFF_ALLMULTI)
+                dev_set_allmulti(master, dev->flags & IFF_ALLMULTI ? 1 : -1);
+        if (change & IFF_PROMISC)
+                dev_set_promiscuity(master, dev->flags & IFF_PROMISC ? 1 : -1);
+}
+
+static void dsa_slave_set_rx_mode(struct net_device *dev)
+{
+        struct dsa_slave_priv *p = netdev_priv(dev);
+        struct net_device *master = p->parent->master_netdev;
+
+        dev_mc_sync(master, dev);
+        dev_unicast_sync(master, dev);
+}
+
+static int dsa_slave_set_mac_address(struct net_device *dev, void *addr)
+{
+        memcpy(dev->dev_addr, addr + 2, 6);
+
+        return 0;
+}
+
+static int dsa_slave_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
+{
+        struct dsa_slave_priv *p = netdev_priv(dev);
+        struct mii_ioctl_data *mii_data = if_mii(ifr);
+
+        if (p->phy != NULL)
+                return phy_mii_ioctl(p->phy, mii_data, cmd);
+
+        return -EOPNOTSUPP;
+}
+
+
+/* ethtool operations *******************************************************/
+static int
+dsa_slave_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
+{
+        struct dsa_slave_priv *p = netdev_priv(dev);
+        int err;
+
+        err = -EOPNOTSUPP;
+        if (p->phy != NULL) {
+                err = phy_read_status(p->phy);
+                if (err == 0)
+                        err = phy_ethtool_gset(p->phy, cmd);
+        }
+
+        return err;
+}
+
+static int
+dsa_slave_set_settings(struct net_device *dev, struct ethtool_cmd *cmd)
+{
+        struct dsa_slave_priv *p = netdev_priv(dev);
+
+        if (p->phy != NULL)
+                return phy_ethtool_sset(p->phy, cmd);
+
+        return -EOPNOTSUPP;
+}
+
+static void dsa_slave_get_drvinfo(struct net_device *dev,
+                                  struct ethtool_drvinfo *drvinfo)
+{
+        strncpy(drvinfo->driver, "dsa", 32);
+        strncpy(drvinfo->version, dsa_driver_version, 32);
+        strncpy(drvinfo->fw_version, "N/A", 32);
+        strncpy(drvinfo->bus_info, "platform", 32);
+}
+
+static int dsa_slave_nway_reset(struct net_device *dev)
+{
+        struct dsa_slave_priv *p = netdev_priv(dev);
+
+        if (p->phy != NULL)
+                return genphy_restart_aneg(p->phy);
+
+        return -EOPNOTSUPP;
+}
+
+static u32 dsa_slave_get_link(struct net_device *dev)
+{
+        struct dsa_slave_priv *p = netdev_priv(dev);
+
+        if (p->phy != NULL) {
+                genphy_update_link(p->phy);
+                return p->phy->link;
+        }
+
+        return -EOPNOTSUPP;
+}
+
+static void dsa_slave_get_strings(struct net_device *dev,
+                                  uint32_t stringset, uint8_t *data)
+{
+        struct dsa_slave_priv *p = netdev_priv(dev);
+        struct dsa_switch *ds = p->parent;
+
+        if (stringset == ETH_SS_STATS) {
+                int len = ETH_GSTRING_LEN;
+
+                strncpy(data, "tx_packets", len);
+                strncpy(data + len, "tx_bytes", len);
+                strncpy(data + 2 * len, "rx_packets", len);
+                strncpy(data + 3 * len, "rx_bytes", len);
+                if (ds->drv->get_strings != NULL)
+                        ds->drv->get_strings(ds, p->port, data + 4 * len);
+        }
+}
+
+static void dsa_slave_get_ethtool_stats(struct net_device *dev,
+                                        struct ethtool_stats *stats,
+                                        uint64_t *data)
+{
+        struct dsa_slave_priv *p = netdev_priv(dev);
+        struct dsa_switch *ds = p->parent;
+
+        data[0] = p->dev->stats.tx_packets;
+        data[1] = p->dev->stats.tx_bytes;
+        data[2] = p->dev->stats.rx_packets;
+        data[3] = p->dev->stats.rx_bytes;
+        if (ds->drv->get_ethtool_stats != NULL)
+                ds->drv->get_ethtool_stats(ds, p->port, data + 4);
+}
+
+static int dsa_slave_get_sset_count(struct net_device *dev, int sset)
+{
+        struct dsa_slave_priv *p = netdev_priv(dev);
+        struct dsa_switch *ds = p->parent;
+
+        if (sset == ETH_SS_STATS) {
+                int count;
+
+                count = 4;
+                if (ds->drv->get_sset_count != NULL)
+                        count += ds->drv->get_sset_count(ds);
+
+                return count;
+        }
+
+        return -EOPNOTSUPP;
+}
+
+static const struct ethtool_ops dsa_slave_ethtool_ops = {
+        .get_settings           = dsa_slave_get_settings,
+        .set_settings           = dsa_slave_set_settings,
+        .get_drvinfo            = dsa_slave_get_drvinfo,
+        .nway_reset             = dsa_slave_nway_reset,
+        .get_link               = dsa_slave_get_link,
+        .set_sg                 = ethtool_op_set_sg,
+        .get_strings            = dsa_slave_get_strings,
+        .get_ethtool_stats      = dsa_slave_get_ethtool_stats,
+        .get_sset_count         = dsa_slave_get_sset_count,
+};
+
+
+/* slave device setup *******************************************************/
+struct net_device *
+dsa_slave_create(struct dsa_switch *ds, struct device *parent,
+                 int port, char *name)
+{
+        struct net_device *master = ds->master_netdev;
+        struct net_device *slave_dev;
+        struct dsa_slave_priv *p;
+        int ret;
+
+        slave_dev = alloc_netdev(sizeof(struct dsa_slave_priv),
+                                 name, ether_setup);
+        if (slave_dev == NULL)
+                return slave_dev;
+
+        slave_dev->features = master->vlan_features;
+        SET_ETHTOOL_OPS(slave_dev, &dsa_slave_ethtool_ops);
+        memcpy(slave_dev->dev_addr, master->dev_addr, ETH_ALEN);
+        slave_dev->tx_queue_len = 0;
+        switch (ds->tag_protocol) {
+#ifdef CONFIG_NET_DSA_TAG_EDSA
+        case htons(ETH_P_EDSA):
+                slave_dev->hard_start_xmit = edsa_xmit;
+                break;
+#endif
+        default:
+                BUG();
+        }
+        slave_dev->open = dsa_slave_open;
+        slave_dev->stop = dsa_slave_close;
+        slave_dev->change_rx_flags = dsa_slave_change_rx_flags;
+        slave_dev->set_rx_mode = dsa_slave_set_rx_mode;
+        slave_dev->set_multicast_list = dsa_slave_set_rx_mode;
+        slave_dev->set_mac_address = dsa_slave_set_mac_address;
+        slave_dev->do_ioctl = dsa_slave_ioctl;
+        SET_NETDEV_DEV(slave_dev, parent);
+        slave_dev->vlan_features = master->vlan_features;
+
+        p = netdev_priv(slave_dev);
+        p->dev = slave_dev;
+        p->parent = ds;
+        p->port = port;
+        p->phy = ds->slave_mii_bus->phy_map[port];
+
+        ret = register_netdev(slave_dev);
+        if (ret) {
+                printk(KERN_ERR "%s: error %d registering interface %s\n",
+                                master->name, ret, slave_dev->name);
+                free_netdev(slave_dev);
+                return NULL;
+        }
+
+        netif_carrier_off(slave_dev);
+
+        if (p->phy != NULL) {
+                phy_attach(slave_dev, p->phy->dev.bus_id,
+                           0, PHY_INTERFACE_MODE_GMII);
+
+                p->phy->autoneg = AUTONEG_ENABLE;
+                p->phy->speed = 0;
+                p->phy->duplex = 0;
+                p->phy->advertising = p->phy->supported | ADVERTISED_Autoneg;
+                phy_start_aneg(p->phy);
+        }
+
+        return slave_dev;
+}