// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * net/dsa/slave.c - Slave device handling
 * Copyright (c) 2008-2009 Marvell Semiconductor
 */

#include <linux/list.h>
#include <linux/etherdevice.h>
#include <linux/netdevice.h>
#include <linux/phy.h>
#include <linux/phy_fixed.h>
#include <linux/phylink.h>
#include <linux/of_net.h>
#include <linux/of_mdio.h>
#include <linux/mdio.h>
#include <net/rtnetlink.h>
#include <net/pkt_cls.h>
#include <net/selftests.h>
#include <net/tc_act/tc_mirred.h>
#include <linux/if_bridge.h>
#include <linux/if_hsr.h>
#include <linux/netpoll.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->phys_mii_mask & (1 << addr))
                return ds->ops->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->phys_mii_mask & (1 << addr))
                return ds->ops->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, "dsa-%d.%d",
                 ds->dst->index, ds->index);
        ds->slave_mii_bus->parent = ds->dev;
        ds->slave_mii_bus->phy_mask = ~ds->phys_mii_mask;
}


/* slave device handling ****************************************************/
static int dsa_slave_get_iflink(const struct net_device *dev)
{
        return dsa_slave_to_master(dev)->ifindex;
}

static int dsa_slave_open(struct net_device *dev)
{
        struct net_device *master = dsa_slave_to_master(dev);
        struct dsa_port *dp = dsa_slave_to_port(dev);
        int err;

        err = dev_open(master, NULL);
        if (err < 0) {
                netdev_err(dev, "failed to open master %s\n", master->name);
                goto out;
        }

        if (!ether_addr_equal(dev->dev_addr, master->dev_addr)) {
                err = dev_uc_add(master, dev->dev_addr);
                if (err < 0)
                        goto out;
        }

        if (dev->flags & IFF_ALLMULTI) {
                err = dev_set_allmulti(master, 1);
                if (err < 0)
                        goto del_unicast;
        }
        if (dev->flags & IFF_PROMISC) {
                err = dev_set_promiscuity(master, 1);
                if (err < 0)
                        goto clear_allmulti;
        }

        err = dsa_port_enable_rt(dp, dev->phydev);
        if (err)
                goto clear_promisc;

        return 0;

clear_promisc:
        if (dev->flags & IFF_PROMISC)
                dev_set_promiscuity(master, -1);
clear_allmulti:
        if (dev->flags & IFF_ALLMULTI)
                dev_set_allmulti(master, -1);
del_unicast:
        if (!ether_addr_equal(dev->dev_addr, master->dev_addr))
                dev_uc_del(master, dev->dev_addr);
out:
        return err;
}

static int dsa_slave_close(struct net_device *dev)
{
        struct net_device *master = dsa_slave_to_master(dev);
        struct dsa_port *dp = dsa_slave_to_port(dev);

        dsa_port_disable_rt(dp);

        dev_mc_unsync(master, dev);
        dev_uc_unsync(master, dev);
        if (dev->flags & IFF_ALLMULTI)
                dev_set_allmulti(master, -1);
        if (dev->flags & IFF_PROMISC)
                dev_set_promiscuity(master, -1);

        if (!ether_addr_equal(dev->dev_addr, master->dev_addr))
                dev_uc_del(master, dev->dev_addr);

        return 0;
}

static void dsa_slave_change_rx_flags(struct net_device *dev, int change)
{
        struct net_device *master = dsa_slave_to_master(dev);
        if (dev->flags & IFF_UP) {
                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 net_device *master = dsa_slave_to_master(dev);

        dev_mc_sync(master, dev);
        dev_uc_sync(master, dev);
}

static int dsa_slave_set_mac_address(struct net_device *dev, void *a)
{
        struct net_device *master = dsa_slave_to_master(dev);
        struct sockaddr *addr = a;
        int err;

        if (!is_valid_ether_addr(addr->sa_data))
                return -EADDRNOTAVAIL;

        if (!(dev->flags & IFF_UP))
                goto out;

        if (!ether_addr_equal(addr->sa_data, master->dev_addr)) {
                err = dev_uc_add(master, addr->sa_data);
                if (err < 0)
                        return err;
        }

        if (!ether_addr_equal(dev->dev_addr, master->dev_addr))
                dev_uc_del(master, dev->dev_addr);

out:
        ether_addr_copy(dev->dev_addr, addr->sa_data);

        return 0;
}

struct dsa_slave_dump_ctx {
        struct net_device *dev;
        struct sk_buff *skb;
        struct netlink_callback *cb;
        int idx;
};

static int
dsa_slave_port_fdb_do_dump(const unsigned char *addr, u16 vid,
                           bool is_static, void *data)
{
        struct dsa_slave_dump_ctx *dump = data;
        u32 portid = NETLINK_CB(dump->cb->skb).portid;
        u32 seq = dump->cb->nlh->nlmsg_seq;
        struct nlmsghdr *nlh;
        struct ndmsg *ndm;

        if (dump->idx < dump->cb->args[2])
                goto skip;

        nlh = nlmsg_put(dump->skb, portid, seq, RTM_NEWNEIGH,
                        sizeof(*ndm), NLM_F_MULTI);
        if (!nlh)
                return -EMSGSIZE;

        ndm = nlmsg_data(nlh);
        ndm->ndm_family  = AF_BRIDGE;
        ndm->ndm_pad1    = 0;
        ndm->ndm_pad2    = 0;
        ndm->ndm_flags   = NTF_SELF;
        ndm->ndm_type    = 0;
        ndm->ndm_ifindex = dump->dev->ifindex;
        ndm->ndm_state   = is_static ? NUD_NOARP : NUD_REACHABLE;

        if (nla_put(dump->skb, NDA_LLADDR, ETH_ALEN, addr))
                goto nla_put_failure;

        if (vid && nla_put_u16(dump->skb, NDA_VLAN, vid))
                goto nla_put_failure;

        nlmsg_end(dump->skb, nlh);

skip:
        dump->idx++;
        return 0;

nla_put_failure:
        nlmsg_cancel(dump->skb, nlh);
        return -EMSGSIZE;
}

static int
dsa_slave_fdb_dump(struct sk_buff *skb, struct netlink_callback *cb,
                   struct net_device *dev, struct net_device *filter_dev,
                   int *idx)
{
        struct dsa_port *dp = dsa_slave_to_port(dev);
        struct dsa_slave_dump_ctx dump = {
                .dev = dev,
                .skb = skb,
                .cb = cb,
                .idx = *idx,
        };
        int err;

        err = dsa_port_fdb_dump(dp, dsa_slave_port_fdb_do_dump, &dump);
        *idx = dump.idx;

        return err;
}

static int dsa_slave_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
{
        struct dsa_slave_priv *p = netdev_priv(dev);
        struct dsa_switch *ds = p->dp->ds;
        int port = p->dp->index;

        /* Pass through to switch driver if it supports timestamping */
        switch (cmd) {
        case SIOCGHWTSTAMP:
                if (ds->ops->port_hwtstamp_get)
                        return ds->ops->port_hwtstamp_get(ds, port, ifr);
                break;
        case SIOCSHWTSTAMP:
                if (ds->ops->port_hwtstamp_set)
                        return ds->ops->port_hwtstamp_set(ds, port, ifr);
                break;
        }

        return phylink_mii_ioctl(p->dp->pl, ifr, cmd);
}

static int dsa_slave_port_attr_set(struct net_device *dev, const void *ctx,
                                   const struct switchdev_attr *attr,
                                   struct netlink_ext_ack *extack)
{
        struct dsa_port *dp = dsa_slave_to_port(dev);
        int ret;

        if (ctx && ctx != dp)
                return 0;

        switch (attr->id) {
        case SWITCHDEV_ATTR_ID_PORT_STP_STATE:
                if (!dsa_port_offloads_bridge_port(dp, attr->orig_dev))
                        return -EOPNOTSUPP;

                ret = dsa_port_set_state(dp, attr->u.stp_state, true);
                break;
        case SWITCHDEV_ATTR_ID_BRIDGE_VLAN_FILTERING:
                if (!dsa_port_offloads_bridge(dp, attr->orig_dev))
                        return -EOPNOTSUPP;

                ret = dsa_port_vlan_filtering(dp, attr->u.vlan_filtering,
                                              extack);
                break;
        case SWITCHDEV_ATTR_ID_BRIDGE_AGEING_TIME:
                if (!dsa_port_offloads_bridge(dp, attr->orig_dev))
                        return -EOPNOTSUPP;

                ret = dsa_port_ageing_time(dp, attr->u.ageing_time);
                break;
        case SWITCHDEV_ATTR_ID_PORT_PRE_BRIDGE_FLAGS:
                if (!dsa_port_offloads_bridge_port(dp, attr->orig_dev))
                        return -EOPNOTSUPP;

                ret = dsa_port_pre_bridge_flags(dp, attr->u.brport_flags,
                                                extack);
                break;
        case SWITCHDEV_ATTR_ID_PORT_BRIDGE_FLAGS:
                if (!dsa_port_offloads_bridge_port(dp, attr->orig_dev))
                        return -EOPNOTSUPP;

                ret = dsa_port_bridge_flags(dp, attr->u.brport_flags, extack);
                break;
        default:
                ret = -EOPNOTSUPP;
                break;
        }

        return ret;
}

/* Must be called under rcu_read_lock() */
static int
dsa_slave_vlan_check_for_8021q_uppers(struct net_device *slave,
                                      const struct switchdev_obj_port_vlan *vlan)
{
        struct net_device *upper_dev;
        struct list_head *iter;

        netdev_for_each_upper_dev_rcu(slave, upper_dev, iter) {
                u16 vid;

                if (!is_vlan_dev(upper_dev))
                        continue;

                vid = vlan_dev_vlan_id(upper_dev);
                if (vid == vlan->vid)
                        return -EBUSY;
        }

        return 0;
}

static int dsa_slave_vlan_add(struct net_device *dev,
                              const struct switchdev_obj *obj,
                              struct netlink_ext_ack *extack)
{
        struct net_device *master = dsa_slave_to_master(dev);
        struct dsa_port *dp = dsa_slave_to_port(dev);
        struct switchdev_obj_port_vlan vlan;
        int err;

        if (dsa_port_skip_vlan_configuration(dp)) {
                NL_SET_ERR_MSG_MOD(extack, "skipping configuration of VLAN");
                return 0;
        }

        vlan = *SWITCHDEV_OBJ_PORT_VLAN(obj);

        /* Deny adding a bridge VLAN when there is already an 802.1Q upper with
         * the same VID.
         */
        if (br_vlan_enabled(dp->bridge_dev)) {
                rcu_read_lock();
                err = dsa_slave_vlan_check_for_8021q_uppers(dev, &vlan);
                rcu_read_unlock();
                if (err) {
                        NL_SET_ERR_MSG_MOD(extack,
                                           "Port already has a VLAN upper with this VID");
                        return err;
                }
        }

        err = dsa_port_vlan_add(dp, &vlan, extack);
        if (err)
                return err;

        /* We need the dedicated CPU port to be a member of the VLAN as well.
         * Even though drivers often handle CPU membership in special ways,
         * it doesn't make sense to program a PVID, so clear this flag.
         */
        vlan.flags &= ~BRIDGE_VLAN_INFO_PVID;

        err = dsa_port_vlan_add(dp->cpu_dp, &vlan, extack);
        if (err)
                return err;

        return vlan_vid_add(master, htons(ETH_P_8021Q), vlan.vid);
}

static int dsa_slave_port_obj_add(struct net_device *dev, const void *ctx,
                                  const struct switchdev_obj *obj,
                                  struct netlink_ext_ack *extack)
{
        struct dsa_port *dp = dsa_slave_to_port(dev);
        int err;

        if (ctx && ctx != dp)
                return 0;

        switch (obj->id) {
        case SWITCHDEV_OBJ_ID_PORT_MDB:
                if (!dsa_port_offloads_bridge_port(dp, obj->orig_dev))
                        return -EOPNOTSUPP;

                err = dsa_port_mdb_add(dp, SWITCHDEV_OBJ_PORT_MDB(obj));
                break;
        case SWITCHDEV_OBJ_ID_HOST_MDB:
                if (!dsa_port_offloads_bridge(dp, obj->orig_dev))
                        return -EOPNOTSUPP;

                err = dsa_port_host_mdb_add(dp, SWITCHDEV_OBJ_PORT_MDB(obj));
                break;
        case SWITCHDEV_OBJ_ID_PORT_VLAN:
                if (!dsa_port_offloads_bridge_port(dp, obj->orig_dev))
                        return -EOPNOTSUPP;

                err = dsa_slave_vlan_add(dev, obj, extack);
                break;
        case SWITCHDEV_OBJ_ID_MRP:
                if (!dsa_port_offloads_bridge(dp, obj->orig_dev))
                        return -EOPNOTSUPP;

                err = dsa_port_mrp_add(dp, SWITCHDEV_OBJ_MRP(obj));
                break;
        case SWITCHDEV_OBJ_ID_RING_ROLE_MRP:
                if (!dsa_port_offloads_bridge(dp, obj->orig_dev))
                        return -EOPNOTSUPP;

                err = dsa_port_mrp_add_ring_role(dp,
                                                 SWITCHDEV_OBJ_RING_ROLE_MRP(obj));
                break;
        default:
                err = -EOPNOTSUPP;
                break;
        }

        return err;
}

static int dsa_slave_vlan_del(struct net_device *dev,
                              const struct switchdev_obj *obj)
{
        struct net_device *master = dsa_slave_to_master(dev);
        struct dsa_port *dp = dsa_slave_to_port(dev);
        struct switchdev_obj_port_vlan *vlan;
        int err;

        if (dsa_port_skip_vlan_configuration(dp))
                return 0;

        vlan = SWITCHDEV_OBJ_PORT_VLAN(obj);

        /* Do not deprogram the CPU port as it may be shared with other user
         * ports which can be members of this VLAN as well.
         */
        err = dsa_port_vlan_del(dp, vlan);
        if (err)
                return err;

        vlan_vid_del(master, htons(ETH_P_8021Q), vlan->vid);

        return 0;
}

static int dsa_slave_port_obj_del(struct net_device *dev, const void *ctx,
                                  const struct switchdev_obj *obj)
{
        struct dsa_port *dp = dsa_slave_to_port(dev);
        int err;

        if (ctx && ctx != dp)
                return 0;

        switch (obj->id) {
        case SWITCHDEV_OBJ_ID_PORT_MDB:
                if (!dsa_port_offloads_bridge_port(dp, obj->orig_dev))
                        return -EOPNOTSUPP;

                err = dsa_port_mdb_del(dp, SWITCHDEV_OBJ_PORT_MDB(obj));
                break;
        case SWITCHDEV_OBJ_ID_HOST_MDB:
                if (!dsa_port_offloads_bridge(dp, obj->orig_dev))
                        return -EOPNOTSUPP;

                err = dsa_port_host_mdb_del(dp, SWITCHDEV_OBJ_PORT_MDB(obj));
                break;
        case SWITCHDEV_OBJ_ID_PORT_VLAN:
                if (!dsa_port_offloads_bridge_port(dp, obj->orig_dev))
                        return -EOPNOTSUPP;

                err = dsa_slave_vlan_del(dev, obj);
                break;
        case SWITCHDEV_OBJ_ID_MRP:
                if (!dsa_port_offloads_bridge(dp, obj->orig_dev))
                        return -EOPNOTSUPP;

                err = dsa_port_mrp_del(dp, SWITCHDEV_OBJ_MRP(obj));
                break;
        case SWITCHDEV_OBJ_ID_RING_ROLE_MRP:
                if (!dsa_port_offloads_bridge(dp, obj->orig_dev))
                        return -EOPNOTSUPP;

                err = dsa_port_mrp_del_ring_role(dp,
                                                 SWITCHDEV_OBJ_RING_ROLE_MRP(obj));
                break;
        default:
                err = -EOPNOTSUPP;
                break;
        }

        return err;
}

static int dsa_slave_get_port_parent_id(struct net_device *dev,
                                        struct netdev_phys_item_id *ppid)
{
        struct dsa_port *dp = dsa_slave_to_port(dev);
        struct dsa_switch *ds = dp->ds;
        struct dsa_switch_tree *dst = ds->dst;

        /* For non-legacy ports, devlink is used and it takes
         * care of the name generation. This ndo implementation
         * should be removed with legacy support.
         */
        if (dp->ds->devlink)
                return -EOPNOTSUPP;

        ppid->id_len = sizeof(dst->index);
        memcpy(&ppid->id, &dst->index, ppid->id_len);

        return 0;
}

static inline netdev_tx_t dsa_slave_netpoll_send_skb(struct net_device *dev,
                                                     struct sk_buff *skb)
{
#ifdef CONFIG_NET_POLL_CONTROLLER
        struct dsa_slave_priv *p = netdev_priv(dev);

        return netpoll_send_skb(p->netpoll, skb);
#else
        BUG();
        return NETDEV_TX_OK;
#endif
}

static void dsa_skb_tx_timestamp(struct dsa_slave_priv *p,
                                 struct sk_buff *skb)
{
        struct dsa_switch *ds = p->dp->ds;

        if (!(skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP))
                return;

        if (!ds->ops->port_txtstamp)
                return;

        ds->ops->port_txtstamp(ds, p->dp->index, skb);
}

netdev_tx_t dsa_enqueue_skb(struct sk_buff *skb, struct net_device *dev)
{
        /* SKB for netpoll still need to be mangled with the protocol-specific
         * tag to be successfully transmitted
         */
        if (unlikely(netpoll_tx_running(dev)))
                return dsa_slave_netpoll_send_skb(dev, skb);

        /* Queue the SKB for transmission on the parent interface, but
         * do not modify its EtherType
         */
        skb->dev = dsa_slave_to_master(dev);
        dev_queue_xmit(skb);

        return NETDEV_TX_OK;
}
EXPORT_SYMBOL_GPL(dsa_enqueue_skb);

static int dsa_realloc_skb(struct sk_buff *skb, struct net_device *dev)
{
        int needed_headroom = dev->needed_headroom;
        int needed_tailroom = dev->needed_tailroom;

        /* For tail taggers, we need to pad short frames ourselves, to ensure
         * that the tail tag does not fail at its role of being at the end of
         * the packet, once the master interface pads the frame. Account for
         * that pad length here, and pad later.
         */
        if (unlikely(needed_tailroom && skb->len < ETH_ZLEN))
                needed_tailroom += ETH_ZLEN - skb->len;
        /* skb_headroom() returns unsigned int... */
        needed_headroom = max_t(int, needed_headroom - skb_headroom(skb), 0);
        needed_tailroom = max_t(int, needed_tailroom - skb_tailroom(skb), 0);

        if (likely(!needed_headroom && !needed_tailroom && !skb_cloned(skb)))
                /* No reallocation needed, yay! */
                return 0;

        return pskb_expand_head(skb, needed_headroom, needed_tailroom,
                                GFP_ATOMIC);
}

static netdev_tx_t dsa_slave_xmit(struct sk_buff *skb, struct net_device *dev)
{
        struct dsa_slave_priv *p = netdev_priv(dev);
        struct sk_buff *nskb;

        dev_sw_netstats_tx_add(dev, 1, skb->len);

        memset(skb->cb, 0, sizeof(skb->cb));

        /* Handle tx timestamp if any */
        dsa_skb_tx_timestamp(p, skb);

        if (dsa_realloc_skb(skb, dev)) {
                dev_kfree_skb_any(skb);
                return NETDEV_TX_OK;
        }

        /* needed_tailroom should still be 'warm' in the cache line from
         * dsa_realloc_skb(), which has also ensured that padding is safe.
         */
        if (dev->needed_tailroom)
                eth_skb_pad(skb);

        /* Transmit function may have to reallocate the original SKB,
         * in which case it must have freed it. Only free it here on error.
         */
        nskb = p->xmit(skb, dev);
        if (!nskb) {
                kfree_skb(skb);
                return NETDEV_TX_OK;
        }

        return dsa_enqueue_skb(nskb, dev);
}

/* ethtool operations *******************************************************/

static void dsa_slave_get_drvinfo(struct net_device *dev,
                                  struct ethtool_drvinfo *drvinfo)
{
        strlcpy(drvinfo->driver, "dsa", sizeof(drvinfo->driver));
        strlcpy(drvinfo->fw_version, "N/A", sizeof(drvinfo->fw_version));
        strlcpy(drvinfo->bus_info, "platform", sizeof(drvinfo->bus_info));
}

static int dsa_slave_get_regs_len(struct net_device *dev)
{
        struct dsa_port *dp = dsa_slave_to_port(dev);
        struct dsa_switch *ds = dp->ds;

        if (ds->ops->get_regs_len)
                return ds->ops->get_regs_len(ds, dp->index);

        return -EOPNOTSUPP;
}

static void
dsa_slave_get_regs(struct net_device *dev, struct ethtool_regs *regs, void *_p)
{
        struct dsa_port *dp = dsa_slave_to_port(dev);
        struct dsa_switch *ds = dp->ds;

        if (ds->ops->get_regs)
                ds->ops->get_regs(ds, dp->index, regs, _p);
}

static int dsa_slave_nway_reset(struct net_device *dev)
{
        struct dsa_port *dp = dsa_slave_to_port(dev);

        return phylink_ethtool_nway_reset(dp->pl);
}

static int dsa_slave_get_eeprom_len(struct net_device *dev)
{
        struct dsa_port *dp = dsa_slave_to_port(dev);
        struct dsa_switch *ds = dp->ds;

        if (ds->cd && ds->cd->eeprom_len)
                return ds->cd->eeprom_len;

        if (ds->ops->get_eeprom_len)
                return ds->ops->get_eeprom_len(ds);

        return 0;
}

static int dsa_slave_get_eeprom(struct net_device *dev,
                                struct ethtool_eeprom *eeprom, u8 *data)
{
        struct dsa_port *dp = dsa_slave_to_port(dev);
        struct dsa_switch *ds = dp->ds;

        if (ds->ops->get_eeprom)
                return ds->ops->get_eeprom(ds, eeprom, data);

        return -EOPNOTSUPP;
}

static int dsa_slave_set_eeprom(struct net_device *dev,
                                struct ethtool_eeprom *eeprom, u8 *data)
{
        struct dsa_port *dp = dsa_slave_to_port(dev);
        struct dsa_switch *ds = dp->ds;

        if (ds->ops->set_eeprom)
                return ds->ops->set_eeprom(ds, eeprom, data);

        return -EOPNOTSUPP;
}

static void dsa_slave_get_strings(struct net_device *dev,
                                  uint32_t stringset, uint8_t *data)
{
        struct dsa_port *dp = dsa_slave_to_port(dev);
        struct dsa_switch *ds = dp->ds;

        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->ops->get_strings)
                        ds->ops->get_strings(ds, dp->index, stringset,
                                             data + 4 * len);
        } else if (stringset ==  ETH_SS_TEST) {
                net_selftest_get_strings(data);
        }

}

static void dsa_slave_get_ethtool_stats(struct net_device *dev,
                                        struct ethtool_stats *stats,
                                        uint64_t *data)
{
        struct dsa_port *dp = dsa_slave_to_port(dev);
        struct dsa_switch *ds = dp->ds;
        struct pcpu_sw_netstats *s;
        unsigned int start;
        int i;

        for_each_possible_cpu(i) {
                u64 tx_packets, tx_bytes, rx_packets, rx_bytes;

                s = per_cpu_ptr(dev->tstats, i);
                do {
                        start = u64_stats_fetch_begin_irq(&s->syncp);
                        tx_packets = s->tx_packets;
                        tx_bytes = s->tx_bytes;
                        rx_packets = s->rx_packets;
                        rx_bytes = s->rx_bytes;
                } while (u64_stats_fetch_retry_irq(&s->syncp, start));
                data[0] += tx_packets;
                data[1] += tx_bytes;
                data[2] += rx_packets;
                data[3] += rx_bytes;
        }
        if (ds->ops->get_ethtool_stats)
                ds->ops->get_ethtool_stats(ds, dp->index, data + 4);
}

static int dsa_slave_get_sset_count(struct net_device *dev, int sset)
{
        struct dsa_port *dp = dsa_slave_to_port(dev);
        struct dsa_switch *ds = dp->ds;

        if (sset == ETH_SS_STATS) {
                int count = 0;

                if (ds->ops->get_sset_count) {
                        count = ds->ops->get_sset_count(ds, dp->index, sset);
                        if (count < 0)
                                return count;
                }

                return count + 4;
        } else if (sset ==  ETH_SS_TEST) {
                return net_selftest_get_count();
        }

        return -EOPNOTSUPP;
}

static void dsa_slave_net_selftest(struct net_device *ndev,
                                   struct ethtool_test *etest, u64 *buf)
{
        struct dsa_port *dp = dsa_slave_to_port(ndev);
        struct dsa_switch *ds = dp->ds;

        if (ds->ops->self_test) {
                ds->ops->self_test(ds, dp->index, etest, buf);
                return;
        }

        net_selftest(ndev, etest, buf);
}

static void dsa_slave_get_wol(struct net_device *dev, struct ethtool_wolinfo *w)
{
        struct dsa_port *dp = dsa_slave_to_port(dev);
        struct dsa_switch *ds = dp->ds;

        phylink_ethtool_get_wol(dp->pl, w);

        if (ds->ops->get_wol)
                ds->ops->get_wol(ds, dp->index, w);
}

static int dsa_slave_set_wol(struct net_device *dev, struct ethtool_wolinfo *w)
{
        struct dsa_port *dp = dsa_slave_to_port(dev);
        struct dsa_switch *ds = dp->ds;
        int ret = -EOPNOTSUPP;

        phylink_ethtool_set_wol(dp->pl, w);

        if (ds->ops->set_wol)
                ret = ds->ops->set_wol(ds, dp->index, w);

        return ret;
}

static int dsa_slave_set_eee(struct net_device *dev, struct ethtool_eee *e)
{
        struct dsa_port *dp = dsa_slave_to_port(dev);
        struct dsa_switch *ds = dp->ds;
        int ret;

        /* Port's PHY and MAC both need to be EEE capable */
        if (!dev->phydev || !dp->pl)
                return -ENODEV;

        if (!ds->ops->set_mac_eee)
                return -EOPNOTSUPP;

        ret = ds->ops->set_mac_eee(ds, dp->index, e);
        if (ret)
                return ret;

        return phylink_ethtool_set_eee(dp->pl, e);
}

static int dsa_slave_get_eee(struct net_device *dev, struct ethtool_eee *e)
{
        struct dsa_port *dp = dsa_slave_to_port(dev);
        struct dsa_switch *ds = dp->ds;
        int ret;

        /* Port's PHY and MAC both need to be EEE capable */
        if (!dev->phydev || !dp->pl)
                return -ENODEV;

        if (!ds->ops->get_mac_eee)
                return -EOPNOTSUPP;

        ret = ds->ops->get_mac_eee(ds, dp->index, e);
        if (ret)
                return ret;

        return phylink_ethtool_get_eee(dp->pl, e);
}

static int dsa_slave_get_link_ksettings(struct net_device *dev,
                                        struct ethtool_link_ksettings *cmd)
{
        struct dsa_port *dp = dsa_slave_to_port(dev);

        return phylink_ethtool_ksettings_get(dp->pl, cmd);
}

static int dsa_slave_set_link_ksettings(struct net_device *dev,
                                        const struct ethtool_link_ksettings *cmd)
{
        struct dsa_port *dp = dsa_slave_to_port(dev);

        return phylink_ethtool_ksettings_set(dp->pl, cmd);
}

static void dsa_slave_get_pauseparam(struct net_device *dev,
                                     struct ethtool_pauseparam *pause)
{
        struct dsa_port *dp = dsa_slave_to_port(dev);

        phylink_ethtool_get_pauseparam(dp->pl, pause);
}

static int dsa_slave_set_pauseparam(struct net_device *dev,
                                    struct ethtool_pauseparam *pause)
{
        struct dsa_port *dp = dsa_slave_to_port(dev);

        return phylink_ethtool_set_pauseparam(dp->pl, pause);
}

#ifdef CONFIG_NET_POLL_CONTROLLER
static int dsa_slave_netpoll_setup(struct net_device *dev,
                                   struct netpoll_info *ni)
{
        struct net_device *master = dsa_slave_to_master(dev);
        struct dsa_slave_priv *p = netdev_priv(dev);
        struct netpoll *netpoll;
        int err = 0;

        netpoll = kzalloc(sizeof(*netpoll), GFP_KERNEL);
        if (!netpoll)
                return -ENOMEM;

        err = __netpoll_setup(netpoll, master);
        if (err) {
                kfree(netpoll);
                goto out;
        }

        p->netpoll = netpoll;
out:
        return err;
}

static void dsa_slave_netpoll_cleanup(struct net_device *dev)
{
        struct dsa_slave_priv *p = netdev_priv(dev);
        struct netpoll *netpoll = p->netpoll;

        if (!netpoll)
                return;

        p->netpoll = NULL;

        __netpoll_free(netpoll);
}

static void dsa_slave_poll_controller(struct net_device *dev)
{
}
#endif

static int dsa_slave_get_phys_port_name(struct net_device *dev,
                                        char *name, size_t len)
{
        struct dsa_port *dp = dsa_slave_to_port(dev);

        /* For non-legacy ports, devlink is used and it takes
         * care of the name generation. This ndo implementation
         * should be removed with legacy support.
         */
        if (dp->ds->devlink)
                return -EOPNOTSUPP;

        if (snprintf(name, len, "p%d", dp->index) >= len)
                return -EINVAL;

        return 0;
}

static struct dsa_mall_tc_entry *
dsa_slave_mall_tc_entry_find(struct net_device *dev, unsigned long cookie)
{
        struct dsa_slave_priv *p = netdev_priv(dev);
        struct dsa_mall_tc_entry *mall_tc_entry;

        list_for_each_entry(mall_tc_entry, &p->mall_tc_list, list)
                if (mall_tc_entry->cookie == cookie)
                        return mall_tc_entry;

        return NULL;
}

static int
dsa_slave_add_cls_matchall_mirred(struct net_device *dev,
                                  struct tc_cls_matchall_offload *cls,
                                  bool ingress)
{
        struct dsa_port *dp = dsa_slave_to_port(dev);
        struct dsa_slave_priv *p = netdev_priv(dev);
        struct dsa_mall_mirror_tc_entry *mirror;
        struct dsa_mall_tc_entry *mall_tc_entry;
        struct dsa_switch *ds = dp->ds;
        struct flow_action_entry *act;
        struct dsa_port *to_dp;
        int err;

        if (!ds->ops->port_mirror_add)
                return -EOPNOTSUPP;

        if (!flow_action_basic_hw_stats_check(&cls->rule->action,
                                              cls->common.extack))
                return -EOPNOTSUPP;

        act = &cls->rule->action.entries[0];

        if (!act->dev)
                return -EINVAL;

        if (!dsa_slave_dev_check(act->dev))
                return -EOPNOTSUPP;

        mall_tc_entry = kzalloc(sizeof(*mall_tc_entry), GFP_KERNEL);
        if (!mall_tc_entry)
                return -ENOMEM;

        mall_tc_entry->cookie = cls->cookie;
        mall_tc_entry->type = DSA_PORT_MALL_MIRROR;
        mirror = &mall_tc_entry->mirror;

        to_dp = dsa_slave_to_port(act->dev);

        mirror->to_local_port = to_dp->index;
        mirror->ingress = ingress;

        err = ds->ops->port_mirror_add(ds, dp->index, mirror, ingress);
        if (err) {
                kfree(mall_tc_entry);
                return err;
        }

        list_add_tail(&mall_tc_entry->list, &p->mall_tc_list);

        return err;
}

static int
dsa_slave_add_cls_matchall_police(struct net_device *dev,
                                  struct tc_cls_matchall_offload *cls,
                                  bool ingress)
{
        struct netlink_ext_ack *extack = cls->common.extack;
        struct dsa_port *dp = dsa_slave_to_port(dev);
        struct dsa_slave_priv *p = netdev_priv(dev);
        struct dsa_mall_policer_tc_entry *policer;
        struct dsa_mall_tc_entry *mall_tc_entry;
        struct dsa_switch *ds = dp->ds;
        struct flow_action_entry *act;
        int err;

        if (!ds->ops->port_policer_add) {
                NL_SET_ERR_MSG_MOD(extack,
                                   "Policing offload not implemented");
                return -EOPNOTSUPP;
        }

        if (!ingress) {
                NL_SET_ERR_MSG_MOD(extack,
                                   "Only supported on ingress qdisc");
                return -EOPNOTSUPP;
        }

        if (!flow_action_basic_hw_stats_check(&cls->rule->action,
                                              cls->common.extack))
                return -EOPNOTSUPP;

        list_for_each_entry(mall_tc_entry, &p->mall_tc_list, list) {
                if (mall_tc_entry->type == DSA_PORT_MALL_POLICER) {
                        NL_SET_ERR_MSG_MOD(extack,
                                           "Only one port policer allowed");
                        return -EEXIST;
                }
        }

        act = &cls->rule->action.entries[0];

        mall_tc_entry = kzalloc(sizeof(*mall_tc_entry), GFP_KERNEL);
        if (!mall_tc_entry)
                return -ENOMEM;

        mall_tc_entry->cookie = cls->cookie;
        mall_tc_entry->type = DSA_PORT_MALL_POLICER;
        policer = &mall_tc_entry->policer;
        policer->rate_bytes_per_sec = act->police.rate_bytes_ps;
        policer->burst = act->police.burst;

        err = ds->ops->port_policer_add(ds, dp->index, policer);
        if (err) {
                kfree(mall_tc_entry);
                return err;
        }

        list_add_tail(&mall_tc_entry->list, &p->mall_tc_list);

        return err;
}

static int dsa_slave_add_cls_matchall(struct net_device *dev,
                                      struct tc_cls_matchall_offload *cls,
                                      bool ingress)
{
        int err = -EOPNOTSUPP;

        if (cls->common.protocol == htons(ETH_P_ALL) &&
            flow_offload_has_one_action(&cls->rule->action) &&
            cls->rule->action.entries[0].id == FLOW_ACTION_MIRRED)
                err = dsa_slave_add_cls_matchall_mirred(dev, cls, ingress);
        else if (flow_offload_has_one_action(&cls->rule->action) &&
                 cls->rule->action.entries[0].id == FLOW_ACTION_POLICE)
                err = dsa_slave_add_cls_matchall_police(dev, cls, ingress);

        return err;
}

static void dsa_slave_del_cls_matchall(struct net_device *dev,
                                       struct tc_cls_matchall_offload *cls)
{
        struct dsa_port *dp = dsa_slave_to_port(dev);
        struct dsa_mall_tc_entry *mall_tc_entry;
        struct dsa_switch *ds = dp->ds;

        mall_tc_entry = dsa_slave_mall_tc_entry_find(dev, cls->cookie);
        if (!mall_tc_entry)
                return;

        list_del(&mall_tc_entry->list);

        switch (mall_tc_entry->type) {
        case DSA_PORT_MALL_MIRROR:
                if (ds->ops->port_mirror_del)
                        ds->ops->port_mirror_del(ds, dp->index,
                                                 &mall_tc_entry->mirror);
                break;
        case DSA_PORT_MALL_POLICER:
                if (ds->ops->port_policer_del)
                        ds->ops->port_policer_del(ds, dp->index);
                break;
        default:
                WARN_ON(1);
        }

        kfree(mall_tc_entry);
}

static int dsa_slave_setup_tc_cls_matchall(struct net_device *dev,
                                           struct tc_cls_matchall_offload *cls,
                                           bool ingress)
{
        if (cls->common.chain_index)
                return -EOPNOTSUPP;

        switch (cls->command) {
        case TC_CLSMATCHALL_REPLACE:
                return dsa_slave_add_cls_matchall(dev, cls, ingress);
        case TC_CLSMATCHALL_DESTROY:
                dsa_slave_del_cls_matchall(dev, cls);
                return 0;
        default:
                return -EOPNOTSUPP;
        }
}

static int dsa_slave_add_cls_flower(struct net_device *dev,
                                    struct flow_cls_offload *cls,
                                    bool ingress)
{
        struct dsa_port *dp = dsa_slave_to_port(dev);
        struct dsa_switch *ds = dp->ds;
        int port = dp->index;

        if (!ds->ops->cls_flower_add)
                return -EOPNOTSUPP;

        return ds->ops->cls_flower_add(ds, port, cls, ingress);
}

static int dsa_slave_del_cls_flower(struct net_device *dev,
                                    struct flow_cls_offload *cls,
                                    bool ingress)
{
        struct dsa_port *dp = dsa_slave_to_port(dev);
        struct dsa_switch *ds = dp->ds;
        int port = dp->index;

        if (!ds->ops->cls_flower_del)
                return -EOPNOTSUPP;

        return ds->ops->cls_flower_del(ds, port, cls, ingress);
}

static int dsa_slave_stats_cls_flower(struct net_device *dev,
                                      struct flow_cls_offload *cls,
                                      bool ingress)
{
        struct dsa_port *dp = dsa_slave_to_port(dev);
        struct dsa_switch *ds = dp->ds;
        int port = dp->index;

        if (!ds->ops->cls_flower_stats)
                return -EOPNOTSUPP;

        return ds->ops->cls_flower_stats(ds, port, cls, ingress);
}

static int dsa_slave_setup_tc_cls_flower(struct net_device *dev,
                                         struct flow_cls_offload *cls,
                                         bool ingress)
{
        switch (cls->command) {
        case FLOW_CLS_REPLACE:
                return dsa_slave_add_cls_flower(dev, cls, ingress);
        case FLOW_CLS_DESTROY:
                return dsa_slave_del_cls_flower(dev, cls, ingress);
        case FLOW_CLS_STATS:
                return dsa_slave_stats_cls_flower(dev, cls, ingress);
        default:
                return -EOPNOTSUPP;
        }
}

static int dsa_slave_setup_tc_block_cb(enum tc_setup_type type, void *type_data,
                                       void *cb_priv, bool ingress)
{
        struct net_device *dev = cb_priv;

        if (!tc_can_offload(dev))
                return -EOPNOTSUPP;

        switch (type) {
        case TC_SETUP_CLSMATCHALL:
                return dsa_slave_setup_tc_cls_matchall(dev, type_data, ingress);
        case TC_SETUP_CLSFLOWER:
                return dsa_slave_setup_tc_cls_flower(dev, type_data, ingress);
        default:
                return -EOPNOTSUPP;
        }
}

static int dsa_slave_setup_tc_block_cb_ig(enum tc_setup_type type,
                                          void *type_data, void *cb_priv)
{
        return dsa_slave_setup_tc_block_cb(type, type_data, cb_priv, true);
}

static int dsa_slave_setup_tc_block_cb_eg(enum tc_setup_type type,
                                          void *type_data, void *cb_priv)
{
        return dsa_slave_setup_tc_block_cb(type, type_data, cb_priv, false);
}

static LIST_HEAD(dsa_slave_block_cb_list);

static int dsa_slave_setup_tc_block(struct net_device *dev,
                                    struct flow_block_offload *f)
{
        struct flow_block_cb *block_cb;
        flow_setup_cb_t *cb;

        if (f->binder_type == FLOW_BLOCK_BINDER_TYPE_CLSACT_INGRESS)
                cb = dsa_slave_setup_tc_block_cb_ig;
        else if (f->binder_type == FLOW_BLOCK_BINDER_TYPE_CLSACT_EGRESS)
                cb = dsa_slave_setup_tc_block_cb_eg;
        else
                return -EOPNOTSUPP;

        f->driver_block_list = &dsa_slave_block_cb_list;

        switch (f->command) {
        case FLOW_BLOCK_BIND:
                if (flow_block_cb_is_busy(cb, dev, &dsa_slave_block_cb_list))
                        return -EBUSY;

                block_cb = flow_block_cb_alloc(cb, dev, dev, NULL);
                if (IS_ERR(block_cb))
                        return PTR_ERR(block_cb);

                flow_block_cb_add(block_cb, f);
                list_add_tail(&block_cb->driver_list, &dsa_slave_block_cb_list);
                return 0;
        case FLOW_BLOCK_UNBIND:
                block_cb = flow_block_cb_lookup(f->block, cb, dev);
                if (!block_cb)
                        return -ENOENT;

                flow_block_cb_remove(block_cb, f);
                list_del(&block_cb->driver_list);
                return 0;
        default:
                return -EOPNOTSUPP;
        }
}

static int dsa_slave_setup_ft_block(struct dsa_switch *ds, int port,
                                    void *type_data)
{
        struct dsa_port *cpu_dp = dsa_to_port(ds, port)->cpu_dp;
        struct net_device *master = cpu_dp->master;

        if (!master->netdev_ops->ndo_setup_tc)
                return -EOPNOTSUPP;

        return master->netdev_ops->ndo_setup_tc(master, TC_SETUP_FT, type_data);
}

static int dsa_slave_setup_tc(struct net_device *dev, enum tc_setup_type type,
                              void *type_data)
{
        struct dsa_port *dp = dsa_slave_to_port(dev);
        struct dsa_switch *ds = dp->ds;

        switch (type) {
        case TC_SETUP_BLOCK:
                return dsa_slave_setup_tc_block(dev, type_data);
        case TC_SETUP_FT:
                return dsa_slave_setup_ft_block(ds, dp->index, type_data);
        default:
                break;
        }

        if (!ds->ops->port_setup_tc)
                return -EOPNOTSUPP;

        return ds->ops->port_setup_tc(ds, dp->index, type, type_data);
}

static int dsa_slave_get_rxnfc(struct net_device *dev,
                               struct ethtool_rxnfc *nfc, u32 *rule_locs)
{
        struct dsa_port *dp = dsa_slave_to_port(dev);
        struct dsa_switch *ds = dp->ds;

        if (!ds->ops->get_rxnfc)
                return -EOPNOTSUPP;

        return ds->ops->get_rxnfc(ds, dp->index, nfc, rule_locs);
}

static int dsa_slave_set_rxnfc(struct net_device *dev,
                               struct ethtool_rxnfc *nfc)
{
        struct dsa_port *dp = dsa_slave_to_port(dev);
        struct dsa_switch *ds = dp->ds;

        if (!ds->ops->set_rxnfc)
                return -EOPNOTSUPP;

        return ds->ops->set_rxnfc(ds, dp->index, nfc);
}

static int dsa_slave_get_ts_info(struct net_device *dev,
                                 struct ethtool_ts_info *ts)
{
        struct dsa_slave_priv *p = netdev_priv(dev);
        struct dsa_switch *ds = p->dp->ds;

        if (!ds->ops->get_ts_info)
                return -EOPNOTSUPP;

        return ds->ops->get_ts_info(ds, p->dp->index, ts);
}

static int dsa_slave_vlan_rx_add_vid(struct net_device *dev, __be16 proto,
                                     u16 vid)
{
        struct net_device *master = dsa_slave_to_master(dev);
        struct dsa_port *dp = dsa_slave_to_port(dev);
        struct switchdev_obj_port_vlan vlan = {
                .obj.id = SWITCHDEV_OBJ_ID_PORT_VLAN,
                .vid = vid,
                /* This API only allows programming tagged, non-PVID VIDs */
                .flags = 0,
        };
        struct netlink_ext_ack extack = {0};
        int ret;

        /* User port... */
        ret = dsa_port_vlan_add(dp, &vlan, &extack);
        if (ret) {
                if (extack._msg)
                        netdev_err(dev, "%s\n", extack._msg);
                return ret;
        }

        /* And CPU port... */
        ret = dsa_port_vlan_add(dp->cpu_dp, &vlan, &extack);
        if (ret) {
                if (extack._msg)
                        netdev_err(dev, "CPU port %d: %s\n", dp->cpu_dp->index,
                                   extack._msg);
                return ret;
        }

        return vlan_vid_add(master, proto, vid);
}

static int dsa_slave_vlan_rx_kill_vid(struct net_device *dev, __be16 proto,
                                      u16 vid)
{
        struct net_device *master = dsa_slave_to_master(dev);
        struct dsa_port *dp = dsa_slave_to_port(dev);
        struct switchdev_obj_port_vlan vlan = {
                .vid = vid,
                /* This API only allows programming tagged, non-PVID VIDs */
                .flags = 0,
        };
        int err;

        /* Do not deprogram the CPU port as it may be shared with other user
         * ports which can be members of this VLAN as well.
         */
        err = dsa_port_vlan_del(dp, &vlan);
        if (err)
                return err;

        vlan_vid_del(master, proto, vid);

        return 0;
}

static int dsa_slave_restore_vlan(struct net_device *vdev, int vid, void *arg)
{
        __be16 proto = vdev ? vlan_dev_vlan_proto(vdev) : htons(ETH_P_8021Q);

        return dsa_slave_vlan_rx_add_vid(arg, proto, vid);
}

static int dsa_slave_clear_vlan(struct net_device *vdev, int vid, void *arg)
{
        __be16 proto = vdev ? vlan_dev_vlan_proto(vdev) : htons(ETH_P_8021Q);

        return dsa_slave_vlan_rx_kill_vid(arg, proto, vid);
}

/* Keep the VLAN RX filtering list in sync with the hardware only if VLAN
 * filtering is enabled. The baseline is that only ports that offload a
 * VLAN-aware bridge are VLAN-aware, and standalone ports are VLAN-unaware,
 * but there are exceptions for quirky hardware.
 *
 * If ds->vlan_filtering_is_global = true, then standalone ports which share
 * the same switch with other ports that offload a VLAN-aware bridge are also
 * inevitably VLAN-aware.
 *
 * To summarize, a DSA switch port offloads:
 *
 * - If standalone (this includes software bridge, software LAG):
 *     - if ds->needs_standalone_vlan_filtering = true, OR if
 *       (ds->vlan_filtering_is_global = true AND there are bridges spanning
 *       this switch chip which have vlan_filtering=1)
 *         - the 8021q upper VLANs
 *     - else (standalone VLAN filtering is not needed, VLAN filtering is not
 *       global, or it is, but no port is under a VLAN-aware bridge):
 *         - no VLAN (any 8021q upper is a software VLAN)
 *
 * - If under a vlan_filtering=0 bridge which it offload:
 *     - if ds->configure_vlan_while_not_filtering = true (default):
 *         - the bridge VLANs. These VLANs are committed to hardware but inactive.
 *     - else (deprecated):
 *         - no VLAN. The bridge VLANs are not restored when VLAN awareness is
 *           enabled, so this behavior is broken and discouraged.
 *
 * - If under a vlan_filtering=1 bridge which it offload:
 *     - the bridge VLANs
 *     - the 8021q upper VLANs
 */
int dsa_slave_manage_vlan_filtering(struct net_device *slave,
                                    bool vlan_filtering)
{
        int err;

        if (vlan_filtering) {
                slave->features |= NETIF_F_HW_VLAN_CTAG_FILTER;

                err = vlan_for_each(slave, dsa_slave_restore_vlan, slave);
                if (err) {
                        vlan_for_each(slave, dsa_slave_clear_vlan, slave);
                        slave->features &= ~NETIF_F_HW_VLAN_CTAG_FILTER;
                        return err;
                }
        } else {
                err = vlan_for_each(slave, dsa_slave_clear_vlan, slave);
                if (err)
                        return err;

                slave->features &= ~NETIF_F_HW_VLAN_CTAG_FILTER;
        }

        return 0;
}

struct dsa_hw_port {
        struct list_head list;
        struct net_device *dev;
        int old_mtu;
};

static int dsa_hw_port_list_set_mtu(struct list_head *hw_port_list, int mtu)
{
        const struct dsa_hw_port *p;
        int err;

        list_for_each_entry(p, hw_port_list, list) {
                if (p->dev->mtu == mtu)
                        continue;

                err = dev_set_mtu(p->dev, mtu);
                if (err)
                        goto rollback;
        }

        return 0;

rollback:
        list_for_each_entry_continue_reverse(p, hw_port_list, list) {
                if (p->dev->mtu == p->old_mtu)
                        continue;

                if (dev_set_mtu(p->dev, p->old_mtu))
                        netdev_err(p->dev, "Failed to restore MTU\n");
        }

        return err;
}

static void dsa_hw_port_list_free(struct list_head *hw_port_list)
{
        struct dsa_hw_port *p, *n;

        list_for_each_entry_safe(p, n, hw_port_list, list)
                kfree(p);
}

/* Make the hardware datapath to/from @dev limited to a common MTU */
static void dsa_bridge_mtu_normalization(struct dsa_port *dp)
{
        struct list_head hw_port_list;
        struct dsa_switch_tree *dst;
        int min_mtu = ETH_MAX_MTU;
        struct dsa_port *other_dp;
        int err;

        if (!dp->ds->mtu_enforcement_ingress)
                return;

        if (!dp->bridge_dev)
                return;

        INIT_LIST_HEAD(&hw_port_list);

        /* Populate the list of ports that are part of the same bridge
         * as the newly added/modified port
         */
        list_for_each_entry(dst, &dsa_tree_list, list) {
                list_for_each_entry(other_dp, &dst->ports, list) {
                        struct dsa_hw_port *hw_port;
                        struct net_device *slave;

                        if (other_dp->type != DSA_PORT_TYPE_USER)
                                continue;

                        if (other_dp->bridge_dev != dp->bridge_dev)
                                continue;

                        if (!other_dp->ds->mtu_enforcement_ingress)
                                continue;

                        slave = other_dp->slave;

                        if (min_mtu > slave->mtu)
                                min_mtu = slave->mtu;

                        hw_port = kzalloc(sizeof(*hw_port), GFP_KERNEL);
                        if (!hw_port)
                                goto out;

                        hw_port->dev = slave;
                        hw_port->old_mtu = slave->mtu;

                        list_add(&hw_port->list, &hw_port_list);
                }
        }

        /* Attempt to configure the entire hardware bridge to the newly added
         * interface's MTU first, regardless of whether the intention of the
         * user was to raise or lower it.
         */
        err = dsa_hw_port_list_set_mtu(&hw_port_list, dp->slave->mtu);
        if (!err)
                goto out;

        /* Clearly that didn't work out so well, so just set the minimum MTU on
         * all hardware bridge ports now. If this fails too, then all ports will
         * still have their old MTU rolled back anyway.
         */
        dsa_hw_port_list_set_mtu(&hw_port_list, min_mtu);

out:
        dsa_hw_port_list_free(&hw_port_list);
}

int dsa_slave_change_mtu(struct net_device *dev, int new_mtu)
{
        struct net_device *master = dsa_slave_to_master(dev);
        struct dsa_port *dp = dsa_slave_to_port(dev);
        struct dsa_slave_priv *p = netdev_priv(dev);
        struct dsa_switch *ds = p->dp->ds;
        struct dsa_port *dp_iter;
        struct dsa_port *cpu_dp;
        int port = p->dp->index;
        int largest_mtu = 0;
        int new_master_mtu;
        int old_master_mtu;
        int mtu_limit;
        int cpu_mtu;
        int err;

        if (!ds->ops->port_change_mtu)
                return -EOPNOTSUPP;

        list_for_each_entry(dp_iter, &ds->dst->ports, list) {
                int slave_mtu;

                if (!dsa_port_is_user(dp_iter))
                        continue;

                /* During probe, this function will be called for each slave
                 * device, while not all of them have been allocated. That's
                 * ok, it doesn't change what the maximum is, so ignore it.
                 */
                if (!dp_iter->slave)
                        continue;

                /* Pretend that we already applied the setting, which we
                 * actually haven't (still haven't done all integrity checks)
                 */
                if (dp_iter == dp)
                        slave_mtu = new_mtu;
                else
                        slave_mtu = dp_iter->slave->mtu;

                if (largest_mtu < slave_mtu)
                        largest_mtu = slave_mtu;
        }

        cpu_dp = dsa_to_port(ds, port)->cpu_dp;

        mtu_limit = min_t(int, master->max_mtu, dev->max_mtu);
        old_master_mtu = master->mtu;
        new_master_mtu = largest_mtu + dsa_tag_protocol_overhead(cpu_dp->tag_ops);
        if (new_master_mtu > mtu_limit)
                return -ERANGE;

        /* If the master MTU isn't over limit, there's no need to check the CPU
         * MTU, since that surely isn't either.
         */
        cpu_mtu = largest_mtu;

        /* Start applying stuff */
        if (new_master_mtu != old_master_mtu) {
                err = dev_set_mtu(master, new_master_mtu);
                if (err < 0)
                        goto out_master_failed;

                /* We only need to propagate the MTU of the CPU port to
                 * upstream switches, so create a non-targeted notifier which
                 * updates all switches.
                 */
                err = dsa_port_mtu_change(cpu_dp, cpu_mtu, false);
                if (err)
                        goto out_cpu_failed;
        }

        err = dsa_port_mtu_change(dp, new_mtu, true);
        if (err)
                goto out_port_failed;

        dev->mtu = new_mtu;

        dsa_bridge_mtu_normalization(dp);

        return 0;

out_port_failed:
        if (new_master_mtu != old_master_mtu)
                dsa_port_mtu_change(cpu_dp, old_master_mtu -
                                    dsa_tag_protocol_overhead(cpu_dp->tag_ops),
                                    false);
out_cpu_failed:
        if (new_master_mtu != old_master_mtu)
                dev_set_mtu(master, old_master_mtu);
out_master_failed:
        return err;
}

static const struct ethtool_ops dsa_slave_ethtool_ops = {
        .get_drvinfo            = dsa_slave_get_drvinfo,
        .get_regs_len           = dsa_slave_get_regs_len,
        .get_regs               = dsa_slave_get_regs,
        .nway_reset             = dsa_slave_nway_reset,
        .get_link               = ethtool_op_get_link,
        .get_eeprom_len         = dsa_slave_get_eeprom_len,
        .get_eeprom             = dsa_slave_get_eeprom,
        .set_eeprom             = dsa_slave_set_eeprom,
        .get_strings            = dsa_slave_get_strings,
        .get_ethtool_stats      = dsa_slave_get_ethtool_stats,
        .get_sset_count         = dsa_slave_get_sset_count,
        .set_wol                = dsa_slave_set_wol,
        .get_wol                = dsa_slave_get_wol,
        .set_eee                = dsa_slave_set_eee,
        .get_eee                = dsa_slave_get_eee,
        .get_link_ksettings     = dsa_slave_get_link_ksettings,
        .set_link_ksettings     = dsa_slave_set_link_ksettings,
        .get_pauseparam         = dsa_slave_get_pauseparam,
        .set_pauseparam         = dsa_slave_set_pauseparam,
        .get_rxnfc              = dsa_slave_get_rxnfc,
        .set_rxnfc              = dsa_slave_set_rxnfc,
        .get_ts_info            = dsa_slave_get_ts_info,
        .self_test              = dsa_slave_net_selftest,
};

static struct devlink_port *dsa_slave_get_devlink_port(struct net_device *dev)
{
        struct dsa_port *dp = dsa_slave_to_port(dev);

        return dp->ds->devlink ? &dp->devlink_port : NULL;
}

static void dsa_slave_get_stats64(struct net_device *dev,
                                  struct rtnl_link_stats64 *s)
{
        struct dsa_port *dp = dsa_slave_to_port(dev);
        struct dsa_switch *ds = dp->ds;

        if (ds->ops->get_stats64)
                ds->ops->get_stats64(ds, dp->index, s);
        else
                dev_get_tstats64(dev, s);
}

static int dsa_slave_fill_forward_path(struct net_device_path_ctx *ctx,
                                       struct net_device_path *path)
{
        struct dsa_port *dp = dsa_slave_to_port(ctx->dev);
        struct dsa_port *cpu_dp = dp->cpu_dp;

        path->dev = ctx->dev;
        path->type = DEV_PATH_DSA;
        path->dsa.proto = cpu_dp->tag_ops->proto;
        path->dsa.port = dp->index;
        ctx->dev = cpu_dp->master;

        return 0;
}

static const struct net_device_ops dsa_slave_netdev_ops = {
        .ndo_open               = dsa_slave_open,
        .ndo_stop               = dsa_slave_close,
        .ndo_start_xmit         = dsa_slave_xmit,
        .ndo_change_rx_flags    = dsa_slave_change_rx_flags,
        .ndo_set_rx_mode        = dsa_slave_set_rx_mode,
        .ndo_set_mac_address    = dsa_slave_set_mac_address,
        .ndo_fdb_dump           = dsa_slave_fdb_dump,
        .ndo_eth_ioctl          = dsa_slave_ioctl,
        .ndo_get_iflink         = dsa_slave_get_iflink,
#ifdef CONFIG_NET_POLL_CONTROLLER
        .ndo_netpoll_setup      = dsa_slave_netpoll_setup,
        .ndo_netpoll_cleanup    = dsa_slave_netpoll_cleanup,
        .ndo_poll_controller    = dsa_slave_poll_controller,
#endif
        .ndo_get_phys_port_name = dsa_slave_get_phys_port_name,
        .ndo_setup_tc           = dsa_slave_setup_tc,
        .ndo_get_stats64        = dsa_slave_get_stats64,
        .ndo_get_port_parent_id = dsa_slave_get_port_parent_id,
        .ndo_vlan_rx_add_vid    = dsa_slave_vlan_rx_add_vid,
        .ndo_vlan_rx_kill_vid   = dsa_slave_vlan_rx_kill_vid,
        .ndo_get_devlink_port   = dsa_slave_get_devlink_port,
        .ndo_change_mtu         = dsa_slave_change_mtu,
        .ndo_fill_forward_path  = dsa_slave_fill_forward_path,
};

static struct device_type dsa_type = {
        .name   = "dsa",
};

void dsa_port_phylink_mac_change(struct dsa_switch *ds, int port, bool up)
{
        const struct dsa_port *dp = dsa_to_port(ds, port);

        if (dp->pl)
                phylink_mac_change(dp->pl, up);
}
EXPORT_SYMBOL_GPL(dsa_port_phylink_mac_change);

static void dsa_slave_phylink_fixed_state(struct phylink_config *config,
                                          struct phylink_link_state *state)
{
        struct dsa_port *dp = container_of(config, struct dsa_port, pl_config);
        struct dsa_switch *ds = dp->ds;

        /* No need to check that this operation is valid, the callback would
         * not be called if it was not.
         */
        ds->ops->phylink_fixed_state(ds, dp->index, state);
}

/* slave device setup *******************************************************/
static int dsa_slave_phy_connect(struct net_device *slave_dev, int addr,
                                 u32 flags)
{
        struct dsa_port *dp = dsa_slave_to_port(slave_dev);
        struct dsa_switch *ds = dp->ds;

        slave_dev->phydev = mdiobus_get_phy(ds->slave_mii_bus, addr);
        if (!slave_dev->phydev) {
                netdev_err(slave_dev, "no phy at %d\n", addr);
                return -ENODEV;
        }

        slave_dev->phydev->dev_flags |= flags;

        return phylink_connect_phy(dp->pl, slave_dev->phydev);
}

static int dsa_slave_phy_setup(struct net_device *slave_dev)
{
        struct dsa_port *dp = dsa_slave_to_port(slave_dev);
        struct device_node *port_dn = dp->dn;
        struct dsa_switch *ds = dp->ds;
        phy_interface_t mode;
        u32 phy_flags = 0;
        int ret;

        ret = of_get_phy_mode(port_dn, &mode);
        if (ret)
                mode = PHY_INTERFACE_MODE_NA;

        dp->pl_config.dev = &slave_dev->dev;
        dp->pl_config.type = PHYLINK_NETDEV;

        /* The get_fixed_state callback takes precedence over polling the
         * link GPIO in PHYLINK (see phylink_get_fixed_state).  Only set
         * this if the switch provides such a callback.
         */
        if (ds->ops->phylink_fixed_state) {
                dp->pl_config.get_fixed_state = dsa_slave_phylink_fixed_state;
                dp->pl_config.poll_fixed_state = true;
        }

        dp->pl = phylink_create(&dp->pl_config, of_fwnode_handle(port_dn), mode,
                                &dsa_port_phylink_mac_ops);
        if (IS_ERR(dp->pl)) {
                netdev_err(slave_dev,
                           "error creating PHYLINK: %ld\n", PTR_ERR(dp->pl));
                return PTR_ERR(dp->pl);
        }

        if (ds->ops->get_phy_flags)
                phy_flags = ds->ops->get_phy_flags(ds, dp->index);

        ret = phylink_of_phy_connect(dp->pl, port_dn, phy_flags);
        if (ret == -ENODEV && ds->slave_mii_bus) {
                /* We could not connect to a designated PHY or SFP, so try to
                 * use the switch internal MDIO bus instead
                 */
                ret = dsa_slave_phy_connect(slave_dev, dp->index, phy_flags);
        }
        if (ret) {
                netdev_err(slave_dev, "failed to connect to PHY: %pe\n",
                           ERR_PTR(ret));
                phylink_destroy(dp->pl);
        }

        return ret;
}

void dsa_slave_setup_tagger(struct net_device *slave)
{
        struct dsa_port *dp = dsa_slave_to_port(slave);
        struct dsa_slave_priv *p = netdev_priv(slave);
        const struct dsa_port *cpu_dp = dp->cpu_dp;
        struct net_device *master = cpu_dp->master;
        const struct dsa_switch *ds = dp->ds;

        slave->needed_headroom = cpu_dp->tag_ops->needed_headroom;
        slave->needed_tailroom = cpu_dp->tag_ops->needed_tailroom;
        /* Try to save one extra realloc later in the TX path (in the master)
         * by also inheriting the master's needed headroom and tailroom.
         * The 8021q driver also does this.
         */
        slave->needed_headroom += master->needed_headroom;
        slave->needed_tailroom += master->needed_tailroom;

        p->xmit = cpu_dp->tag_ops->xmit;

        slave->features = master->vlan_features | NETIF_F_HW_TC;
        slave->hw_features |= NETIF_F_HW_TC;
        slave->features |= NETIF_F_LLTX;
        if (slave->needed_tailroom)
                slave->features &= ~(NETIF_F_SG | NETIF_F_FRAGLIST);
        if (ds->needs_standalone_vlan_filtering)
                slave->features |= NETIF_F_HW_VLAN_CTAG_FILTER;
}

static struct lock_class_key dsa_slave_netdev_xmit_lock_key;
static void dsa_slave_set_lockdep_class_one(struct net_device *dev,
                                            struct netdev_queue *txq,
                                            void *_unused)
{
        lockdep_set_class(&txq->_xmit_lock,
                          &dsa_slave_netdev_xmit_lock_key);
}

int dsa_slave_suspend(struct net_device *slave_dev)
{
        struct dsa_port *dp = dsa_slave_to_port(slave_dev);

        if (!netif_running(slave_dev))
                return 0;

        netif_device_detach(slave_dev);

        rtnl_lock();
        phylink_stop(dp->pl);
        rtnl_unlock();

        return 0;
}

int dsa_slave_resume(struct net_device *slave_dev)
{
        struct dsa_port *dp = dsa_slave_to_port(slave_dev);

        if (!netif_running(slave_dev))
                return 0;

        netif_device_attach(slave_dev);

        rtnl_lock();
        phylink_start(dp->pl);
        rtnl_unlock();

        return 0;
}

int dsa_slave_create(struct dsa_port *port)
{
        const struct dsa_port *cpu_dp = port->cpu_dp;
        struct net_device *master = cpu_dp->master;
        struct dsa_switch *ds = port->ds;
        const char *name = port->name;
        struct net_device *slave_dev;
        struct dsa_slave_priv *p;
        int ret;

        if (!ds->num_tx_queues)
                ds->num_tx_queues = 1;

        slave_dev = alloc_netdev_mqs(sizeof(struct dsa_slave_priv), name,
                                     NET_NAME_UNKNOWN, ether_setup,
                                     ds->num_tx_queues, 1);
        if (slave_dev == NULL)
                return -ENOMEM;

        slave_dev->ethtool_ops = &dsa_slave_ethtool_ops;
        if (!is_zero_ether_addr(port->mac))
                ether_addr_copy(slave_dev->dev_addr, port->mac);
        else
                eth_hw_addr_inherit(slave_dev, master);
        slave_dev->priv_flags |= IFF_NO_QUEUE;
        slave_dev->netdev_ops = &dsa_slave_netdev_ops;
        if (ds->ops->port_max_mtu)
                slave_dev->max_mtu = ds->ops->port_max_mtu(ds, port->index);
        SET_NETDEV_DEVTYPE(slave_dev, &dsa_type);

        netdev_for_each_tx_queue(slave_dev, dsa_slave_set_lockdep_class_one,
                                 NULL);

        SET_NETDEV_DEV(slave_dev, port->ds->dev);
        slave_dev->dev.of_node = port->dn;
        slave_dev->vlan_features = master->vlan_features;

        p = netdev_priv(slave_dev);
        slave_dev->tstats = netdev_alloc_pcpu_stats(struct pcpu_sw_netstats);
        if (!slave_dev->tstats) {
                free_netdev(slave_dev);
                return -ENOMEM;
        }

        ret = gro_cells_init(&p->gcells, slave_dev);
        if (ret)
                goto out_free;

        p->dp = port;
        INIT_LIST_HEAD(&p->mall_tc_list);
        port->slave = slave_dev;
        dsa_slave_setup_tagger(slave_dev);

        rtnl_lock();
        ret = dsa_slave_change_mtu(slave_dev, ETH_DATA_LEN);
        rtnl_unlock();
        if (ret && ret != -EOPNOTSUPP)
                dev_warn(ds->dev, "nonfatal error %d setting MTU to %d on port %d\n",
                         ret, ETH_DATA_LEN, port->index);

        netif_carrier_off(slave_dev);

        ret = dsa_slave_phy_setup(slave_dev);
        if (ret) {
                netdev_err(slave_dev,

                           "error %d setting up PHY for tree %d, switch %d, port %d\n",
                           ret, ds->dst->index, ds->index, port->index);
                goto out_gcells;
        }

        rtnl_lock();

        ret = register_netdevice(slave_dev);
        if (ret) {
                netdev_err(master, "error %d registering interface %s\n",
                           ret, slave_dev->name);
                rtnl_unlock();
                goto out_phy;
        }

        ret = netdev_upper_dev_link(master, slave_dev, NULL);

        rtnl_unlock();

        if (ret)
                goto out_unregister;

        return 0;

out_unregister:
        unregister_netdev(slave_dev);
out_phy:
        rtnl_lock();
        phylink_disconnect_phy(p->dp->pl);
        rtnl_unlock();
        phylink_destroy(p->dp->pl);
out_gcells:
        gro_cells_destroy(&p->gcells);
out_free:
        free_percpu(slave_dev->tstats);
        free_netdev(slave_dev);
        port->slave = NULL;
        return ret;
}

void dsa_slave_destroy(struct net_device *slave_dev)
{
        struct net_device *master = dsa_slave_to_master(slave_dev);
        struct dsa_port *dp = dsa_slave_to_port(slave_dev);
        struct dsa_slave_priv *p = netdev_priv(slave_dev);

        netif_carrier_off(slave_dev);
        rtnl_lock();
        netdev_upper_dev_unlink(master, slave_dev);
        unregister_netdevice(slave_dev);
        phylink_disconnect_phy(dp->pl);
        rtnl_unlock();

        phylink_destroy(dp->pl);
        gro_cells_destroy(&p->gcells);
        free_percpu(slave_dev->tstats);
        free_netdev(slave_dev);
}

bool dsa_slave_dev_check(const struct net_device *dev)
{
        return dev->netdev_ops == &dsa_slave_netdev_ops;
}
EXPORT_SYMBOL_GPL(dsa_slave_dev_check);

static int dsa_slave_changeupper(struct net_device *dev,
                                 struct netdev_notifier_changeupper_info *info)
{
        struct dsa_port *dp = dsa_slave_to_port(dev);
        struct netlink_ext_ack *extack;
        int err = NOTIFY_DONE;

        extack = netdev_notifier_info_to_extack(&info->info);

        if (netif_is_bridge_master(info->upper_dev)) {
                if (info->linking) {
                        err = dsa_port_bridge_join(dp, info->upper_dev, extack);
                        if (!err)
                                dsa_bridge_mtu_normalization(dp);
                        if (err == -EOPNOTSUPP) {
                                NL_SET_ERR_MSG_MOD(extack,
                                                   "Offloading not supported");
                                err = 0;
                        }
                        err = notifier_from_errno(err);
                } else {
                        dsa_port_bridge_leave(dp, info->upper_dev);
                        err = NOTIFY_OK;
                }
        } else if (netif_is_lag_master(info->upper_dev)) {
                if (info->linking) {
                        err = dsa_port_lag_join(dp, info->upper_dev,
                                                info->upper_info, extack);
                        if (err == -EOPNOTSUPP) {
                                NL_SET_ERR_MSG_MOD(info->info.extack,
                                                   "Offloading not supported");
                                err = 0;
                        }
                        err = notifier_from_errno(err);
                } else {
                        dsa_port_lag_leave(dp, info->upper_dev);
                        err = NOTIFY_OK;
                }
        } else if (is_hsr_master(info->upper_dev)) {
                if (info->linking) {
                        err = dsa_port_hsr_join(dp, info->upper_dev);
                        if (err == -EOPNOTSUPP) {
                                NL_SET_ERR_MSG_MOD(info->info.extack,
                                                   "Offloading not supported");
                                err = 0;
                        }
                        err = notifier_from_errno(err);
                } else {
                        dsa_port_hsr_leave(dp, info->upper_dev);
                        err = NOTIFY_OK;
                }
        }

        return err;
}

static int dsa_slave_prechangeupper(struct net_device *dev,
                                    struct netdev_notifier_changeupper_info *info)
{
        struct dsa_port *dp = dsa_slave_to_port(dev);

        if (netif_is_bridge_master(info->upper_dev) && !info->linking)
                dsa_port_pre_bridge_leave(dp, info->upper_dev);
        else if (netif_is_lag_master(info->upper_dev) && !info->linking)
                dsa_port_pre_lag_leave(dp, info->upper_dev);
        /* dsa_port_pre_hsr_leave is not yet necessary since hsr cannot be
         * meaningfully enslaved to a bridge yet
         */

        return NOTIFY_DONE;
}

static int
dsa_slave_lag_changeupper(struct net_device *dev,
                          struct netdev_notifier_changeupper_info *info)
{
        struct net_device *lower;
        struct list_head *iter;
        int err = NOTIFY_DONE;
        struct dsa_port *dp;

        netdev_for_each_lower_dev(dev, lower, iter) {
                if (!dsa_slave_dev_check(lower))
                        continue;

                dp = dsa_slave_to_port(lower);
                if (!dp->lag_dev)
                        /* Software LAG */
                        continue;

                err = dsa_slave_changeupper(lower, info);
                if (notifier_to_errno(err))
                        break;
        }

        return err;
}

/* Same as dsa_slave_lag_changeupper() except that it calls
 * dsa_slave_prechangeupper()
 */
static int
dsa_slave_lag_prechangeupper(struct net_device *dev,
                             struct netdev_notifier_changeupper_info *info)
{
        struct net_device *lower;
        struct list_head *iter;
        int err = NOTIFY_DONE;
        struct dsa_port *dp;

        netdev_for_each_lower_dev(dev, lower, iter) {
                if (!dsa_slave_dev_check(lower))
                        continue;

                dp = dsa_slave_to_port(lower);
                if (!dp->lag_dev)
                        /* Software LAG */
                        continue;

                err = dsa_slave_prechangeupper(lower, info);
                if (notifier_to_errno(err))
                        break;
        }

        return err;
}

static int
dsa_prevent_bridging_8021q_upper(struct net_device *dev,
                                 struct netdev_notifier_changeupper_info *info)
{
        struct netlink_ext_ack *ext_ack;
        struct net_device *slave;
        struct dsa_port *dp;

        ext_ack = netdev_notifier_info_to_extack(&info->info);

        if (!is_vlan_dev(dev))
                return NOTIFY_DONE;

        slave = vlan_dev_real_dev(dev);
        if (!dsa_slave_dev_check(slave))
                return NOTIFY_DONE;

        dp = dsa_slave_to_port(slave);
        if (!dp->bridge_dev)
                return NOTIFY_DONE;

        /* Deny enslaving a VLAN device into a VLAN-aware bridge */
        if (br_vlan_enabled(dp->bridge_dev) &&
            netif_is_bridge_master(info->upper_dev) && info->linking) {
                NL_SET_ERR_MSG_MOD(ext_ack,
                                   "Cannot enslave VLAN device into VLAN aware bridge");
                return notifier_from_errno(-EINVAL);
        }

        return NOTIFY_DONE;
}

static int
dsa_slave_check_8021q_upper(struct net_device *dev,
                            struct netdev_notifier_changeupper_info *info)
{
        struct dsa_port *dp = dsa_slave_to_port(dev);
        struct net_device *br = dp->bridge_dev;
        struct bridge_vlan_info br_info;
        struct netlink_ext_ack *extack;
        int err = NOTIFY_DONE;
        u16 vid;

        if (!br || !br_vlan_enabled(br))
                return NOTIFY_DONE;

        extack = netdev_notifier_info_to_extack(&info->info);
        vid = vlan_dev_vlan_id(info->upper_dev);

        /* br_vlan_get_info() returns -EINVAL or -ENOENT if the
         * device, respectively the VID is not found, returning
         * 0 means success, which is a failure for us here.
         */
        err = br_vlan_get_info(br, vid, &br_info);
        if (err == 0) {
                NL_SET_ERR_MSG_MOD(extack,
                                   "This VLAN is already configured by the bridge");
                return notifier_from_errno(-EBUSY);
        }

        return NOTIFY_DONE;
}

static int
dsa_slave_prechangeupper_sanity_check(struct net_device *dev,
                                      struct netdev_notifier_changeupper_info *info)
{
        struct dsa_switch *ds;
        struct dsa_port *dp;
        int err;

        if (!dsa_slave_dev_check(dev))
                return dsa_prevent_bridging_8021q_upper(dev, info);

        dp = dsa_slave_to_port(dev);
        ds = dp->ds;

        if (ds->ops->port_prechangeupper) {
                err = ds->ops->port_prechangeupper(ds, dp->index, info);
                if (err)
                        return notifier_from_errno(err);
        }

        if (is_vlan_dev(info->upper_dev))
                return dsa_slave_check_8021q_upper(dev, info);

        return NOTIFY_DONE;
}

static int dsa_slave_netdevice_event(struct notifier_block *nb,
                                     unsigned long event, void *ptr)
{
        struct net_device *dev = netdev_notifier_info_to_dev(ptr);

        switch (event) {
        case NETDEV_PRECHANGEUPPER: {
                struct netdev_notifier_changeupper_info *info = ptr;
                int err;

                err = dsa_slave_prechangeupper_sanity_check(dev, info);
                if (err != NOTIFY_DONE)
                        return err;

                if (dsa_slave_dev_check(dev))
                        return dsa_slave_prechangeupper(dev, ptr);

                if (netif_is_lag_master(dev))
                        return dsa_slave_lag_prechangeupper(dev, ptr);

                break;
        }
        case NETDEV_CHANGEUPPER:
                if (dsa_slave_dev_check(dev))
                        return dsa_slave_changeupper(dev, ptr);

                if (netif_is_lag_master(dev))
                        return dsa_slave_lag_changeupper(dev, ptr);

                break;
        case NETDEV_CHANGELOWERSTATE: {
                struct netdev_notifier_changelowerstate_info *info = ptr;
                struct dsa_port *dp;
                int err;

                if (!dsa_slave_dev_check(dev))
                        break;

                dp = dsa_slave_to_port(dev);

                err = dsa_port_lag_change(dp, info->lower_state_info);
                return notifier_from_errno(err);
        }
        case NETDEV_GOING_DOWN: {
                struct dsa_port *dp, *cpu_dp;
                struct dsa_switch_tree *dst;
                LIST_HEAD(close_list);

                if (!netdev_uses_dsa(dev))
                        return NOTIFY_DONE;

                cpu_dp = dev->dsa_ptr;
                dst = cpu_dp->ds->dst;

                list_for_each_entry(dp, &dst->ports, list) {
                        if (!dsa_is_user_port(dp->ds, dp->index))
                                continue;

                        list_add(&dp->slave->close_list, &close_list);
                }

                dev_close_many(&close_list, true);

                return NOTIFY_OK;
        }
        default:
                break;
        }

        return NOTIFY_DONE;
}

static void
dsa_fdb_offload_notify(struct dsa_switchdev_event_work *switchdev_work)
{
        struct switchdev_notifier_fdb_info info = {};
        struct dsa_switch *ds = switchdev_work->ds;
        struct dsa_port *dp;

        if (!dsa_is_user_port(ds, switchdev_work->port))
                return;

        info.addr = switchdev_work->addr;
        info.vid = switchdev_work->vid;
        info.offloaded = true;
        dp = dsa_to_port(ds, switchdev_work->port);
        call_switchdev_notifiers(SWITCHDEV_FDB_OFFLOADED,
                                 dp->slave, &info.info, NULL);
}

static void dsa_slave_switchdev_event_work(struct work_struct *work)
{
        struct dsa_switchdev_event_work *switchdev_work =
                container_of(work, struct dsa_switchdev_event_work, work);
        struct dsa_switch *ds = switchdev_work->ds;
        struct dsa_port *dp;
        int err;

        dp = dsa_to_port(ds, switchdev_work->port);

        rtnl_lock();
        switch (switchdev_work->event) {
        case SWITCHDEV_FDB_ADD_TO_DEVICE:
                if (switchdev_work->host_addr)
                        err = dsa_port_host_fdb_add(dp, switchdev_work->addr,
                                                    switchdev_work->vid);
                else
                        err = dsa_port_fdb_add(dp, switchdev_work->addr,
                                               switchdev_work->vid);
                if (err) {
                        dev_err(ds->dev,
                                "port %d failed to add %pM vid %d to fdb: %d\n",
                                dp->index, switchdev_work->addr,
                                switchdev_work->vid, err);
                        break;
                }
                dsa_fdb_offload_notify(switchdev_work);
                break;

        case SWITCHDEV_FDB_DEL_TO_DEVICE:
                if (switchdev_work->host_addr)
                        err = dsa_port_host_fdb_del(dp, switchdev_work->addr,
                                                    switchdev_work->vid);
                else
                        err = dsa_port_fdb_del(dp, switchdev_work->addr,
                                               switchdev_work->vid);
                if (err) {
                        dev_err(ds->dev,
                                "port %d failed to delete %pM vid %d from fdb: %d\n",
                                dp->index, switchdev_work->addr,
                                switchdev_work->vid, err);
                }

                break;
        }
        rtnl_unlock();

        dev_put(switchdev_work->dev);
        kfree(switchdev_work);
}

static bool dsa_foreign_dev_check(const struct net_device *dev,
                                  const struct net_device *foreign_dev)
{
        const struct dsa_port *dp = dsa_slave_to_port(dev);
        struct dsa_switch_tree *dst = dp->ds->dst;

        if (netif_is_bridge_master(foreign_dev))
                return !dsa_tree_offloads_bridge(dst, foreign_dev);

        if (netif_is_bridge_port(foreign_dev))
                return !dsa_tree_offloads_bridge_port(dst, foreign_dev);

        /* Everything else is foreign */
        return true;
}

static int dsa_slave_fdb_event(struct net_device *dev,
                               const struct net_device *orig_dev,
                               const void *ctx,
                               const struct switchdev_notifier_fdb_info *fdb_info,
                               unsigned long event)
{
        struct dsa_switchdev_event_work *switchdev_work;
        struct dsa_port *dp = dsa_slave_to_port(dev);
        bool host_addr = fdb_info->is_local;
        struct dsa_switch *ds = dp->ds;

        if (ctx && ctx != dp)
                return 0;

        if (!ds->ops->port_fdb_add || !ds->ops->port_fdb_del)
                return -EOPNOTSUPP;

        if (dsa_slave_dev_check(orig_dev) &&
            switchdev_fdb_is_dynamically_learned(fdb_info))
                return 0;

        /* FDB entries learned by the software bridge should be installed as
         * host addresses only if the driver requests assisted learning.
         */
        if (switchdev_fdb_is_dynamically_learned(fdb_info) &&
            !ds->assisted_learning_on_cpu_port)
                return 0;

        /* Also treat FDB entries on foreign interfaces bridged with us as host
         * addresses.
         */
        if (dsa_foreign_dev_check(dev, orig_dev))
                host_addr = true;

        switchdev_work = kzalloc(sizeof(*switchdev_work), GFP_ATOMIC);
        if (!switchdev_work)
                return -ENOMEM;

        netdev_dbg(dev, "%s FDB entry towards %s, addr %pM vid %d%s\n",
                   event == SWITCHDEV_FDB_ADD_TO_DEVICE ? "Adding" : "Deleting",
                   orig_dev->name, fdb_info->addr, fdb_info->vid,
                   host_addr ? " as host address" : "");

        INIT_WORK(&switchdev_work->work, dsa_slave_switchdev_event_work);
        switchdev_work->ds = ds;
        switchdev_work->port = dp->index;
        switchdev_work->event = event;
        switchdev_work->dev = dev;

        ether_addr_copy(switchdev_work->addr, fdb_info->addr);
        switchdev_work->vid = fdb_info->vid;
        switchdev_work->host_addr = host_addr;

        /* Hold a reference for dsa_fdb_offload_notify */
        dev_hold(dev);
        dsa_schedule_work(&switchdev_work->work);

        return 0;
}

static int
dsa_slave_fdb_add_to_device(struct net_device *dev,
                            const struct net_device *orig_dev, const void *ctx,
                            const struct switchdev_notifier_fdb_info *fdb_info)
{
        return dsa_slave_fdb_event(dev, orig_dev, ctx, fdb_info,
                                   SWITCHDEV_FDB_ADD_TO_DEVICE);
}

static int
dsa_slave_fdb_del_to_device(struct net_device *dev,
                            const struct net_device *orig_dev, const void *ctx,
                            const struct switchdev_notifier_fdb_info *fdb_info)
{
        return dsa_slave_fdb_event(dev, orig_dev, ctx, fdb_info,
                                   SWITCHDEV_FDB_DEL_TO_DEVICE);
}

/* Called under rcu_read_lock() */
static int dsa_slave_switchdev_event(struct notifier_block *unused,
                                     unsigned long event, void *ptr)
{
        struct net_device *dev = switchdev_notifier_info_to_dev(ptr);
        int err;

        switch (event) {
        case SWITCHDEV_PORT_ATTR_SET:
                err = switchdev_handle_port_attr_set(dev, ptr,
                                                     dsa_slave_dev_check,
                                                     dsa_slave_port_attr_set);
                return notifier_from_errno(err);
        case SWITCHDEV_FDB_ADD_TO_DEVICE:
                err = switchdev_handle_fdb_add_to_device(dev, ptr,
                                                         dsa_slave_dev_check,
                                                         dsa_foreign_dev_check,
                                                         dsa_slave_fdb_add_to_device,
                                                         NULL);
                return notifier_from_errno(err);
        case SWITCHDEV_FDB_DEL_TO_DEVICE:
                err = switchdev_handle_fdb_del_to_device(dev, ptr,
                                                         dsa_slave_dev_check,
                                                         dsa_foreign_dev_check,
                                                         dsa_slave_fdb_del_to_device,
                                                         NULL);
                return notifier_from_errno(err);
        default:
                return NOTIFY_DONE;
        }

        return NOTIFY_OK;
}

static int dsa_slave_switchdev_blocking_event(struct notifier_block *unused,
                                              unsigned long event, void *ptr)
{
        struct net_device *dev = switchdev_notifier_info_to_dev(ptr);
        int err;

        switch (event) {
        case SWITCHDEV_PORT_OBJ_ADD:
                err = switchdev_handle_port_obj_add(dev, ptr,
                                                    dsa_slave_dev_check,
                                                    dsa_slave_port_obj_add);
                return notifier_from_errno(err);
        case SWITCHDEV_PORT_OBJ_DEL:
                err = switchdev_handle_port_obj_del(dev, ptr,
                                                    dsa_slave_dev_check,
                                                    dsa_slave_port_obj_del);
                return notifier_from_errno(err);
        case SWITCHDEV_PORT_ATTR_SET:
                err = switchdev_handle_port_attr_set(dev, ptr,
                                                     dsa_slave_dev_check,
                                                     dsa_slave_port_attr_set);
                return notifier_from_errno(err);
        }

        return NOTIFY_DONE;
}

static struct notifier_block dsa_slave_nb __read_mostly = {
        .notifier_call  = dsa_slave_netdevice_event,
};

struct notifier_block dsa_slave_switchdev_notifier = {
        .notifier_call = dsa_slave_switchdev_event,
};

struct notifier_block dsa_slave_switchdev_blocking_notifier = {
        .notifier_call = dsa_slave_switchdev_blocking_event,
};

int dsa_slave_register_notifier(void)
{
        struct notifier_block *nb;
        int err;

        err = register_netdevice_notifier(&dsa_slave_nb);
        if (err)
                return err;

        err = register_switchdev_notifier(&dsa_slave_switchdev_notifier);
        if (err)
                goto err_switchdev_nb;

        nb = &dsa_slave_switchdev_blocking_notifier;
        err = register_switchdev_blocking_notifier(nb);
        if (err)
                goto err_switchdev_blocking_nb;

        return 0;

err_switchdev_blocking_nb:
        unregister_switchdev_notifier(&dsa_slave_switchdev_notifier);
err_switchdev_nb:
        unregister_netdevice_notifier(&dsa_slave_nb);
        return err;
}

void dsa_slave_unregister_notifier(void)
{
        struct notifier_block *nb;
        int err;

        nb = &dsa_slave_switchdev_blocking_notifier;
        err = unregister_switchdev_blocking_notifier(nb);
        if (err)
                pr_err("DSA: failed to unregister switchdev blocking notifier (%d)\n", err);

        err = unregister_switchdev_notifier(&dsa_slave_switchdev_notifier);
        if (err)
                pr_err("DSA: failed to unregister switchdev notifier (%d)\n", err);

        err = unregister_netdevice_notifier(&dsa_slave_nb);
        if (err)
                pr_err("DSA: failed to unregister slave notifier (%d)\n", err);
}