// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Handling of a single switch port
 *
 * Copyright (c) 2017 Savoir-faire Linux Inc.
 *      Vivien Didelot <vivien.didelot@savoirfairelinux.com>
 */

#include <linux/if_bridge.h>
#include <linux/netdevice.h>
#include <linux/notifier.h>
#include <linux/of_mdio.h>
#include <linux/of_net.h>

#include "dsa.h"
#include "port.h"
#include "switch.h"
#include "tag_8021q.h"
#include "user.h"

/**
 * dsa_port_notify - Notify the switching fabric of changes to a port
 * @dp: port on which change occurred
 * @e: event, must be of type DSA_NOTIFIER_*
 * @v: event-specific value.
 *
 * Notify all switches in the DSA tree that this port's switch belongs to,
 * including this switch itself, of an event. Allows the other switches to
 * reconfigure themselves for cross-chip operations. Can also be used to
 * reconfigure ports without net_devices (CPU ports, DSA links) whenever
 * a user port's state changes.
 */
static int dsa_port_notify(const struct dsa_port *dp, unsigned long e, void *v)
{
        return dsa_tree_notify(dp->ds->dst, e, v);
}

static void dsa_port_notify_bridge_fdb_flush(const struct dsa_port *dp, u16 vid)
{
        struct net_device *brport_dev = dsa_port_to_bridge_port(dp);
        struct switchdev_notifier_fdb_info info = {
                .vid = vid,
        };

        /* When the port becomes standalone it has already left the bridge.
         * Don't notify the bridge in that case.
         */
        if (!brport_dev)
                return;

        call_switchdev_notifiers(SWITCHDEV_FDB_FLUSH_TO_BRIDGE,
                                 brport_dev, &info.info, NULL);
}

static void dsa_port_fast_age(const struct dsa_port *dp)
{
        struct dsa_switch *ds = dp->ds;

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

        ds->ops->port_fast_age(ds, dp->index);

        /* flush all VLANs */
        dsa_port_notify_bridge_fdb_flush(dp, 0);
}

static int dsa_port_vlan_fast_age(const struct dsa_port *dp, u16 vid)
{
        struct dsa_switch *ds = dp->ds;
        int err;

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

        err = ds->ops->port_vlan_fast_age(ds, dp->index, vid);

        if (!err)
                dsa_port_notify_bridge_fdb_flush(dp, vid);

        return err;
}

static int dsa_port_msti_fast_age(const struct dsa_port *dp, u16 msti)
{
        DECLARE_BITMAP(vids, VLAN_N_VID) = { 0 };
        int err, vid;

        err = br_mst_get_info(dsa_port_bridge_dev_get(dp), msti, vids);
        if (err)
                return err;

        for_each_set_bit(vid, vids, VLAN_N_VID) {
                err = dsa_port_vlan_fast_age(dp, vid);
                if (err)
                        return err;
        }

        return 0;
}

static bool dsa_port_can_configure_learning(struct dsa_port *dp)
{
        struct switchdev_brport_flags flags = {
                .mask = BR_LEARNING,
        };
        struct dsa_switch *ds = dp->ds;
        int err;

        if (!ds->ops->port_bridge_flags || !ds->ops->port_pre_bridge_flags)
                return false;

        err = ds->ops->port_pre_bridge_flags(ds, dp->index, flags, NULL);
        return !err;
}

bool dsa_port_supports_hwtstamp(struct dsa_port *dp)
{
        struct kernel_hwtstamp_config config = {};
        struct dsa_switch *ds = dp->ds;
        int err;

        if (!ds->ops->port_hwtstamp_get || !ds->ops->port_hwtstamp_set)
                return false;

        /* "See through" shim implementations of the "get" method. */
        err = ds->ops->port_hwtstamp_get(ds, dp->index, &config);
        return err != -EOPNOTSUPP;
}

int dsa_port_set_state(struct dsa_port *dp, u8 state, bool do_fast_age)
{
        struct dsa_switch *ds = dp->ds;
        int port = dp->index;

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

        ds->ops->port_stp_state_set(ds, port, state);

        if (!dsa_port_can_configure_learning(dp) ||
            (do_fast_age && dp->learning)) {
                /* Fast age FDB entries or flush appropriate forwarding database
                 * for the given port, if we are moving it from Learning or
                 * Forwarding state, to Disabled or Blocking or Listening state.
                 * Ports that were standalone before the STP state change don't
                 * need to fast age the FDB, since address learning is off in
                 * standalone mode.
                 */

                if ((dp->stp_state == BR_STATE_LEARNING ||
                     dp->stp_state == BR_STATE_FORWARDING) &&
                    (state == BR_STATE_DISABLED ||
                     state == BR_STATE_BLOCKING ||
                     state == BR_STATE_LISTENING))
                        dsa_port_fast_age(dp);
        }

        dp->stp_state = state;

        return 0;
}

static void dsa_port_set_state_now(struct dsa_port *dp, u8 state,
                                   bool do_fast_age)
{
        struct dsa_switch *ds = dp->ds;
        int err;

        err = dsa_port_set_state(dp, state, do_fast_age);
        if (err && err != -EOPNOTSUPP) {
                dev_err(ds->dev, "port %d failed to set STP state %u: %pe\n",
                        dp->index, state, ERR_PTR(err));
        }
}

int dsa_port_set_mst_state(struct dsa_port *dp,
                           const struct switchdev_mst_state *state,
                           struct netlink_ext_ack *extack)
{
        struct dsa_switch *ds = dp->ds;
        u8 prev_state;
        int err;

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

        err = br_mst_get_state(dsa_port_to_bridge_port(dp), state->msti,
                               &prev_state);
        if (err)
                return err;

        err = ds->ops->port_mst_state_set(ds, dp->index, state);
        if (err)
                return err;

        if (!(dp->learning &&
              (prev_state == BR_STATE_LEARNING ||
               prev_state == BR_STATE_FORWARDING) &&
              (state->state == BR_STATE_DISABLED ||
               state->state == BR_STATE_BLOCKING ||
               state->state == BR_STATE_LISTENING)))
                return 0;

        err = dsa_port_msti_fast_age(dp, state->msti);
        if (err)
                NL_SET_ERR_MSG_MOD(extack,
                                   "Unable to flush associated VLANs");

        return 0;
}

int dsa_port_enable_rt(struct dsa_port *dp, struct phy_device *phy)
{
        struct dsa_switch *ds = dp->ds;
        int port = dp->index;
        int err;

        if (ds->ops->port_enable) {
                err = ds->ops->port_enable(ds, port, phy);
                if (err)
                        return err;
        }

        if (!dp->bridge)
                dsa_port_set_state_now(dp, BR_STATE_FORWARDING, false);

        if (dp->pl)
                phylink_start(dp->pl);

        return 0;
}

int dsa_port_enable(struct dsa_port *dp, struct phy_device *phy)
{
        int err;

        rtnl_lock();
        err = dsa_port_enable_rt(dp, phy);
        rtnl_unlock();

        return err;
}

void dsa_port_disable_rt(struct dsa_port *dp)
{
        struct dsa_switch *ds = dp->ds;
        int port = dp->index;

        if (dp->pl)
                phylink_stop(dp->pl);

        if (!dp->bridge)
                dsa_port_set_state_now(dp, BR_STATE_DISABLED, false);

        if (ds->ops->port_disable)
                ds->ops->port_disable(ds, port);
}

void dsa_port_disable(struct dsa_port *dp)
{
        rtnl_lock();
        dsa_port_disable_rt(dp);
        rtnl_unlock();
}

static void dsa_port_reset_vlan_filtering(struct dsa_port *dp,
                                          struct dsa_bridge bridge)
{
        struct netlink_ext_ack extack = {0};
        bool change_vlan_filtering = false;
        struct dsa_switch *ds = dp->ds;
        struct dsa_port *other_dp;
        bool vlan_filtering;
        int err;

        if (ds->needs_standalone_vlan_filtering &&
            !br_vlan_enabled(bridge.dev)) {
                change_vlan_filtering = true;
                vlan_filtering = true;
        } else if (!ds->needs_standalone_vlan_filtering &&
                   br_vlan_enabled(bridge.dev)) {
                change_vlan_filtering = true;
                vlan_filtering = false;
        }

        /* If the bridge was vlan_filtering, the bridge core doesn't trigger an
         * event for changing vlan_filtering setting upon user ports leaving
         * it. That is a good thing, because that lets us handle it and also
         * handle the case where the switch's vlan_filtering setting is global
         * (not per port). When that happens, the correct moment to trigger the
         * vlan_filtering callback is only when the last port leaves the last
         * VLAN-aware bridge.
         */
        if (change_vlan_filtering && ds->vlan_filtering_is_global) {
                dsa_switch_for_each_port(other_dp, ds) {
                        struct net_device *br = dsa_port_bridge_dev_get(other_dp);

                        if (br && br_vlan_enabled(br)) {
                                change_vlan_filtering = false;
                                break;
                        }
                }
        }

        if (!change_vlan_filtering)
                return;

        err = dsa_port_vlan_filtering(dp, vlan_filtering, &extack);
        if (extack._msg) {
                dev_err(ds->dev, "port %d: %s\n", dp->index,
                        extack._msg);
        }
        if (err && err != -EOPNOTSUPP) {
                dev_err(ds->dev,
                        "port %d failed to reset VLAN filtering to %d: %pe\n",
                       dp->index, vlan_filtering, ERR_PTR(err));
        }
}

static int dsa_port_inherit_brport_flags(struct dsa_port *dp,
                                         struct netlink_ext_ack *extack)
{
        const unsigned long mask = BR_LEARNING | BR_FLOOD | BR_MCAST_FLOOD |
                                   BR_BCAST_FLOOD | BR_PORT_LOCKED;
        struct net_device *brport_dev = dsa_port_to_bridge_port(dp);
        int flag, err;

        for_each_set_bit(flag, &mask, 32) {
                struct switchdev_brport_flags flags = {0};

                flags.mask = BIT(flag);

                if (br_port_flag_is_set(brport_dev, BIT(flag)))
                        flags.val = BIT(flag);

                err = dsa_port_bridge_flags(dp, flags, extack);
                if (err && err != -EOPNOTSUPP)
                        return err;
        }

        return 0;
}

static void dsa_port_clear_brport_flags(struct dsa_port *dp)
{
        const unsigned long val = BR_FLOOD | BR_MCAST_FLOOD | BR_BCAST_FLOOD;
        const unsigned long mask = BR_LEARNING | BR_FLOOD | BR_MCAST_FLOOD |
                                   BR_BCAST_FLOOD | BR_PORT_LOCKED;
        int flag, err;

        for_each_set_bit(flag, &mask, 32) {
                struct switchdev_brport_flags flags = {0};

                flags.mask = BIT(flag);
                flags.val = val & BIT(flag);

                err = dsa_port_bridge_flags(dp, flags, NULL);
                if (err && err != -EOPNOTSUPP)
                        dev_err(dp->ds->dev,
                                "failed to clear bridge port flag %lu: %pe\n",
                                flags.val, ERR_PTR(err));
        }
}

static int dsa_port_switchdev_sync_attrs(struct dsa_port *dp,
                                         struct netlink_ext_ack *extack)
{
        struct net_device *brport_dev = dsa_port_to_bridge_port(dp);
        struct net_device *br = dsa_port_bridge_dev_get(dp);
        int err;

        err = dsa_port_inherit_brport_flags(dp, extack);
        if (err)
                return err;

        err = dsa_port_set_state(dp, br_port_get_stp_state(brport_dev), false);
        if (err && err != -EOPNOTSUPP)
                return err;

        err = dsa_port_vlan_filtering(dp, br_vlan_enabled(br), extack);
        if (err && err != -EOPNOTSUPP)
                return err;

        err = dsa_port_ageing_time(dp, br_get_ageing_time(br));
        if (err && err != -EOPNOTSUPP)
                return err;

        return 0;
}

static void dsa_port_switchdev_unsync_attrs(struct dsa_port *dp,
                                            struct dsa_bridge bridge)
{
        /* Configure the port for standalone mode (no address learning,
         * flood everything).
         * The bridge only emits SWITCHDEV_ATTR_ID_PORT_BRIDGE_FLAGS events
         * when the user requests it through netlink or sysfs, but not
         * automatically at port join or leave, so we need to handle resetting
         * the brport flags ourselves. But we even prefer it that way, because
         * otherwise, some setups might never get the notification they need,
         * for example, when a port leaves a LAG that offloads the bridge,
         * it becomes standalone, but as far as the bridge is concerned, no
         * port ever left.
         */
        dsa_port_clear_brport_flags(dp);

        /* Port left the bridge, put in BR_STATE_DISABLED by the bridge layer,
         * so allow it to be in BR_STATE_FORWARDING to be kept functional
         */
        dsa_port_set_state_now(dp, BR_STATE_FORWARDING, true);

        dsa_port_reset_vlan_filtering(dp, bridge);

        /* Ageing time may be global to the switch chip, so don't change it
         * here because we have no good reason (or value) to change it to.
         */
}

static int dsa_port_bridge_create(struct dsa_port *dp,
                                  struct net_device *br,
                                  struct netlink_ext_ack *extack)
{
        struct dsa_switch *ds = dp->ds;
        struct dsa_bridge *bridge;

        bridge = dsa_tree_bridge_find(ds->dst, br);
        if (bridge) {
                refcount_inc(&bridge->refcount);
                dp->bridge = bridge;
                return 0;
        }

        bridge = kzalloc_obj(*bridge);
        if (!bridge)
                return -ENOMEM;

        refcount_set(&bridge->refcount, 1);

        bridge->dev = br;

        bridge->num = dsa_bridge_num_get(br, ds->max_num_bridges);
        if (ds->max_num_bridges && !bridge->num) {
                NL_SET_ERR_MSG_MOD(extack,
                                   "Range of offloadable bridges exceeded");
                kfree(bridge);
                return -EOPNOTSUPP;
        }

        dp->bridge = bridge;

        return 0;
}

static void dsa_port_bridge_destroy(struct dsa_port *dp,
                                    const struct net_device *br)
{
        struct dsa_bridge *bridge = dp->bridge;

        dp->bridge = NULL;

        if (!refcount_dec_and_test(&bridge->refcount))
                return;

        if (bridge->num)
                dsa_bridge_num_put(br, bridge->num);

        kfree(bridge);
}

static bool dsa_port_supports_mst(struct dsa_port *dp)
{
        struct dsa_switch *ds = dp->ds;

        return ds->ops->vlan_msti_set &&
                ds->ops->port_mst_state_set &&
                ds->ops->port_vlan_fast_age &&
                dsa_port_can_configure_learning(dp);
}

int dsa_port_bridge_join(struct dsa_port *dp, struct net_device *br,
                         struct netlink_ext_ack *extack)
{
        struct dsa_notifier_bridge_info info = {
                .dp = dp,
                .extack = extack,
        };
        struct net_device *dev = dp->user;
        struct net_device *brport_dev;
        int err;

        if (br_mst_enabled(br) && !dsa_port_supports_mst(dp))
                return -EOPNOTSUPP;

        /* Here the interface is already bridged. Reflect the current
         * configuration so that drivers can program their chips accordingly.
         */
        err = dsa_port_bridge_create(dp, br, extack);
        if (err)
                return err;

        brport_dev = dsa_port_to_bridge_port(dp);

        info.bridge = *dp->bridge;
        err = dsa_broadcast(DSA_NOTIFIER_BRIDGE_JOIN, &info);
        if (err)
                goto out_rollback;

        /* Drivers which support bridge TX forwarding should set this */
        dp->bridge->tx_fwd_offload = info.tx_fwd_offload;

        err = switchdev_bridge_port_offload(brport_dev, dev, dp,
                                            &dsa_user_switchdev_notifier,
                                            &dsa_user_switchdev_blocking_notifier,
                                            dp->bridge->tx_fwd_offload, extack);
        if (err)
                goto out_rollback_unbridge;

        err = dsa_port_switchdev_sync_attrs(dp, extack);
        if (err)
                goto out_rollback_unoffload;

        return 0;

out_rollback_unoffload:
        switchdev_bridge_port_unoffload(brport_dev, dp,
                                        &dsa_user_switchdev_notifier,
                                        &dsa_user_switchdev_blocking_notifier);
        dsa_flush_workqueue();
out_rollback_unbridge:
        dsa_broadcast(DSA_NOTIFIER_BRIDGE_LEAVE, &info);
out_rollback:
        dsa_port_bridge_destroy(dp, br);
        return err;
}

void dsa_port_pre_bridge_leave(struct dsa_port *dp, struct net_device *br)
{
        struct net_device *brport_dev = dsa_port_to_bridge_port(dp);

        /* Don't try to unoffload something that is not offloaded */
        if (!brport_dev)
                return;

        switchdev_bridge_port_unoffload(brport_dev, dp,
                                        &dsa_user_switchdev_notifier,
                                        &dsa_user_switchdev_blocking_notifier);

        dsa_flush_workqueue();
}

void dsa_port_bridge_leave(struct dsa_port *dp, struct net_device *br)
{
        struct dsa_notifier_bridge_info info = {
                .dp = dp,
        };
        int err;

        /* If the port could not be offloaded to begin with, then
         * there is nothing to do.
         */
        if (!dp->bridge)
                return;

        info.bridge = *dp->bridge;

        /* Here the port is already unbridged. Reflect the current configuration
         * so that drivers can program their chips accordingly.
         */
        dsa_port_bridge_destroy(dp, br);

        err = dsa_broadcast(DSA_NOTIFIER_BRIDGE_LEAVE, &info);
        if (err)
                dev_err(dp->ds->dev,
                        "port %d failed to notify DSA_NOTIFIER_BRIDGE_LEAVE: %pe\n",
                        dp->index, ERR_PTR(err));

        dsa_port_switchdev_unsync_attrs(dp, info.bridge);
}

int dsa_port_lag_change(struct dsa_port *dp,
                        struct netdev_lag_lower_state_info *linfo)
{
        struct dsa_notifier_lag_info info = {
                .dp = dp,
        };
        bool tx_enabled;

        if (!dp->lag)
                return 0;

        /* On statically configured aggregates (e.g. loadbalance
         * without LACP) ports will always be tx_enabled, even if the
         * link is down. Thus we require both link_up and tx_enabled
         * in order to include it in the tx set.
         */
        tx_enabled = linfo->link_up && linfo->tx_enabled;

        if (tx_enabled == dp->lag_tx_enabled)
                return 0;

        dp->lag_tx_enabled = tx_enabled;

        return dsa_port_notify(dp, DSA_NOTIFIER_LAG_CHANGE, &info);
}

static int dsa_port_lag_create(struct dsa_port *dp,
                               struct net_device *lag_dev)
{
        struct dsa_switch *ds = dp->ds;
        struct dsa_lag *lag;

        lag = dsa_tree_lag_find(ds->dst, lag_dev);
        if (lag) {
                refcount_inc(&lag->refcount);
                dp->lag = lag;
                return 0;
        }

        lag = kzalloc_obj(*lag);
        if (!lag)
                return -ENOMEM;

        refcount_set(&lag->refcount, 1);
        mutex_init(&lag->fdb_lock);
        INIT_LIST_HEAD(&lag->fdbs);
        lag->dev = lag_dev;
        dsa_lag_map(ds->dst, lag);
        dp->lag = lag;

        return 0;
}

static void dsa_port_lag_destroy(struct dsa_port *dp)
{
        struct dsa_lag *lag = dp->lag;

        dp->lag = NULL;
        dp->lag_tx_enabled = false;

        if (!refcount_dec_and_test(&lag->refcount))
                return;

        WARN_ON(!list_empty(&lag->fdbs));
        dsa_lag_unmap(dp->ds->dst, lag);
        kfree(lag);
}

int dsa_port_lag_join(struct dsa_port *dp, struct net_device *lag_dev,
                      struct netdev_lag_upper_info *uinfo,
                      struct netlink_ext_ack *extack)
{
        struct dsa_notifier_lag_info info = {
                .dp = dp,
                .info = uinfo,
                .extack = extack,
        };
        struct net_device *bridge_dev;
        int err;

        err = dsa_port_lag_create(dp, lag_dev);
        if (err)
                goto err_lag_create;

        info.lag = *dp->lag;
        err = dsa_port_notify(dp, DSA_NOTIFIER_LAG_JOIN, &info);
        if (err)
                goto err_lag_join;

        bridge_dev = netdev_master_upper_dev_get(lag_dev);
        if (!bridge_dev || !netif_is_bridge_master(bridge_dev))
                return 0;

        err = dsa_port_bridge_join(dp, bridge_dev, extack);
        if (err)
                goto err_bridge_join;

        return 0;

err_bridge_join:
        dsa_port_notify(dp, DSA_NOTIFIER_LAG_LEAVE, &info);
err_lag_join:
        dsa_port_lag_destroy(dp);
err_lag_create:
        return err;
}

void dsa_port_pre_lag_leave(struct dsa_port *dp, struct net_device *lag_dev)
{
        struct net_device *br = dsa_port_bridge_dev_get(dp);

        if (br)
                dsa_port_pre_bridge_leave(dp, br);
}

void dsa_port_lag_leave(struct dsa_port *dp, struct net_device *lag_dev)
{
        struct net_device *br = dsa_port_bridge_dev_get(dp);
        struct dsa_notifier_lag_info info = {
                .dp = dp,
        };
        int err;

        if (!dp->lag)
                return;

        /* Port might have been part of a LAG that in turn was
         * attached to a bridge.
         */
        if (br)
                dsa_port_bridge_leave(dp, br);

        info.lag = *dp->lag;

        dsa_port_lag_destroy(dp);

        err = dsa_port_notify(dp, DSA_NOTIFIER_LAG_LEAVE, &info);
        if (err)
                dev_err(dp->ds->dev,
                        "port %d failed to notify DSA_NOTIFIER_LAG_LEAVE: %pe\n",
                        dp->index, ERR_PTR(err));
}

/* Must be called under rcu_read_lock() */
static bool dsa_port_can_apply_vlan_filtering(struct dsa_port *dp,
                                              bool vlan_filtering,
                                              struct netlink_ext_ack *extack)
{
        struct dsa_switch *ds = dp->ds;
        struct dsa_port *other_dp;
        int err;

        /* VLAN awareness was off, so the question is "can we turn it on".
         * We may have had 8021q uppers, those need to go. Make sure we don't
         * enter an inconsistent state: deny changing the VLAN awareness state
         * as long as we have 8021q uppers.
         */
        if (vlan_filtering && dsa_port_is_user(dp)) {
                struct net_device *br = dsa_port_bridge_dev_get(dp);
                struct net_device *upper_dev, *user = dp->user;
                struct list_head *iter;

                netdev_for_each_upper_dev_rcu(user, upper_dev, iter) {
                        struct bridge_vlan_info br_info;
                        u16 vid;

                        if (!is_vlan_dev(upper_dev))
                                continue;

                        vid = vlan_dev_vlan_id(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,
                                                   "Must first remove VLAN uppers having VIDs also present in bridge");
                                return false;
                        }
                }
        }

        if (!ds->vlan_filtering_is_global)
                return true;

        /* For cases where enabling/disabling VLAN awareness is global to the
         * switch, we need to handle the case where multiple bridges span
         * different ports of the same switch device and one of them has a
         * different setting than what is being requested.
         */
        dsa_switch_for_each_port(other_dp, ds) {
                struct net_device *other_br = dsa_port_bridge_dev_get(other_dp);

                /* If it's the same bridge, it also has same
                 * vlan_filtering setting => no need to check
                 */
                if (!other_br || other_br == dsa_port_bridge_dev_get(dp))
                        continue;

                if (br_vlan_enabled(other_br) != vlan_filtering) {
                        NL_SET_ERR_MSG_MOD(extack,
                                           "VLAN filtering is a global setting");
                        return false;
                }
        }
        return true;
}

int dsa_port_vlan_filtering(struct dsa_port *dp, bool vlan_filtering,
                            struct netlink_ext_ack *extack)
{
        bool old_vlan_filtering = dsa_port_is_vlan_filtering(dp);
        struct dsa_switch *ds = dp->ds;
        bool apply;
        int err;

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

        /* We are called from dsa_user_switchdev_blocking_event(),
         * which is not under rcu_read_lock(), unlike
         * dsa_user_switchdev_event().
         */
        rcu_read_lock();
        apply = dsa_port_can_apply_vlan_filtering(dp, vlan_filtering, extack);
        rcu_read_unlock();
        if (!apply)
                return -EINVAL;

        if (dsa_port_is_vlan_filtering(dp) == vlan_filtering)
                return 0;

        err = ds->ops->port_vlan_filtering(ds, dp->index, vlan_filtering,
                                           extack);
        if (err)
                return err;

        if (ds->vlan_filtering_is_global) {
                struct dsa_port *other_dp;

                ds->vlan_filtering = vlan_filtering;

                dsa_switch_for_each_user_port(other_dp, ds) {
                        struct net_device *user = other_dp->user;

                        /* We might be called in the unbind path, so not
                         * all user devices might still be registered.
                         */
                        if (!user)
                                continue;

                        err = dsa_user_manage_vlan_filtering(user,
                                                             vlan_filtering);
                        if (err)
                                goto restore;
                }
        } else {
                dp->vlan_filtering = vlan_filtering;

                err = dsa_user_manage_vlan_filtering(dp->user,
                                                     vlan_filtering);
                if (err)
                        goto restore;
        }

        return 0;

restore:
        ds->ops->port_vlan_filtering(ds, dp->index, old_vlan_filtering, NULL);

        if (ds->vlan_filtering_is_global)
                ds->vlan_filtering = old_vlan_filtering;
        else
                dp->vlan_filtering = old_vlan_filtering;

        return err;
}

/* This enforces legacy behavior for switch drivers which assume they can't
 * receive VLAN configuration when joining a bridge with vlan_filtering=0
 */
bool dsa_port_skip_vlan_configuration(struct dsa_port *dp)
{
        struct net_device *br = dsa_port_bridge_dev_get(dp);
        struct dsa_switch *ds = dp->ds;

        if (!br)
                return false;

        return !ds->configure_vlan_while_not_filtering && !br_vlan_enabled(br);
}

int dsa_port_ageing_time(struct dsa_port *dp, clock_t ageing_clock)
{
        unsigned long ageing_jiffies = clock_t_to_jiffies(ageing_clock);
        unsigned int ageing_time = jiffies_to_msecs(ageing_jiffies);
        struct dsa_notifier_ageing_time_info info;
        int err;

        info.ageing_time = ageing_time;

        err = dsa_port_notify(dp, DSA_NOTIFIER_AGEING_TIME, &info);
        if (err)
                return err;

        dp->ageing_time = ageing_time;

        return 0;
}

int dsa_port_mst_enable(struct dsa_port *dp, bool on,
                        struct netlink_ext_ack *extack)
{
        if (on && !dsa_port_supports_mst(dp)) {
                NL_SET_ERR_MSG_MOD(extack, "Hardware does not support MST");
                return -EINVAL;
        }

        return 0;
}

int dsa_port_pre_bridge_flags(const struct dsa_port *dp,
                              struct switchdev_brport_flags flags,
                              struct netlink_ext_ack *extack)
{
        struct dsa_switch *ds = dp->ds;

        if (!ds->ops->port_pre_bridge_flags)
                return -EINVAL;

        return ds->ops->port_pre_bridge_flags(ds, dp->index, flags, extack);
}

int dsa_port_bridge_flags(struct dsa_port *dp,
                          struct switchdev_brport_flags flags,
                          struct netlink_ext_ack *extack)
{
        struct dsa_switch *ds = dp->ds;
        int err;

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

        err = ds->ops->port_bridge_flags(ds, dp->index, flags, extack);
        if (err)
                return err;

        if (flags.mask & BR_LEARNING) {
                bool learning = flags.val & BR_LEARNING;

                if (learning == dp->learning)
                        return 0;

                if ((dp->learning && !learning) &&
                    (dp->stp_state == BR_STATE_LEARNING ||
                     dp->stp_state == BR_STATE_FORWARDING))
                        dsa_port_fast_age(dp);

                dp->learning = learning;
        }

        return 0;
}

void dsa_port_set_host_flood(struct dsa_port *dp, bool uc, bool mc)
{
        struct dsa_switch *ds = dp->ds;

        if (ds->ops->port_set_host_flood)
                ds->ops->port_set_host_flood(ds, dp->index, uc, mc);
}

int dsa_port_vlan_msti(struct dsa_port *dp,
                       const struct switchdev_vlan_msti *msti)
{
        struct dsa_switch *ds = dp->ds;

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

        return ds->ops->vlan_msti_set(ds, *dp->bridge, msti);
}

int dsa_port_mtu_change(struct dsa_port *dp, int new_mtu)
{
        struct dsa_notifier_mtu_info info = {
                .dp = dp,
                .mtu = new_mtu,
        };

        return dsa_port_notify(dp, DSA_NOTIFIER_MTU, &info);
}

int dsa_port_fdb_add(struct dsa_port *dp, const unsigned char *addr,
                     u16 vid)
{
        struct dsa_notifier_fdb_info info = {
                .dp = dp,
                .addr = addr,
                .vid = vid,
                .db = {
                        .type = DSA_DB_BRIDGE,
                        .bridge = *dp->bridge,
                },
        };

        /* Refcounting takes bridge.num as a key, and should be global for all
         * bridges in the absence of FDB isolation, and per bridge otherwise.
         * Force the bridge.num to zero here in the absence of FDB isolation.
         */
        if (!dp->ds->fdb_isolation)
                info.db.bridge.num = 0;

        return dsa_port_notify(dp, DSA_NOTIFIER_FDB_ADD, &info);
}

int dsa_port_fdb_del(struct dsa_port *dp, const unsigned char *addr,
                     u16 vid)
{
        struct dsa_notifier_fdb_info info = {
                .dp = dp,
                .addr = addr,
                .vid = vid,
                .db = {
                        .type = DSA_DB_BRIDGE,
                        .bridge = *dp->bridge,
                },
        };

        if (!dp->ds->fdb_isolation)
                info.db.bridge.num = 0;

        return dsa_port_notify(dp, DSA_NOTIFIER_FDB_DEL, &info);
}

static int dsa_port_host_fdb_add(struct dsa_port *dp,
                                 const unsigned char *addr, u16 vid,
                                 struct dsa_db db)
{
        struct dsa_notifier_fdb_info info = {
                .dp = dp,
                .addr = addr,
                .vid = vid,
                .db = db,
        };

        return dsa_port_notify(dp, DSA_NOTIFIER_HOST_FDB_ADD, &info);
}

int dsa_port_standalone_host_fdb_add(struct dsa_port *dp,
                                     const unsigned char *addr, u16 vid)
{
        struct dsa_db db = {
                .type = DSA_DB_PORT,
                .dp = dp,
        };

        return dsa_port_host_fdb_add(dp, addr, vid, db);
}

int dsa_port_bridge_host_fdb_add(struct dsa_port *dp,
                                 const unsigned char *addr, u16 vid)
{
        struct net_device *conduit = dsa_port_to_conduit(dp);
        struct dsa_db db = {
                .type = DSA_DB_BRIDGE,
                .bridge = *dp->bridge,
        };
        int err;

        if (!dp->ds->fdb_isolation)
                db.bridge.num = 0;

        /* Avoid a call to __dev_set_promiscuity() on the conduit, which
         * requires rtnl_lock(), since we can't guarantee that is held here,
         * and we can't take it either.
         */
        if (conduit->priv_flags & IFF_UNICAST_FLT) {
                err = dev_uc_add(conduit, addr);
                if (err)
                        return err;
        }

        return dsa_port_host_fdb_add(dp, addr, vid, db);
}

static int dsa_port_host_fdb_del(struct dsa_port *dp,
                                 const unsigned char *addr, u16 vid,
                                 struct dsa_db db)
{
        struct dsa_notifier_fdb_info info = {
                .dp = dp,
                .addr = addr,
                .vid = vid,
                .db = db,
        };

        return dsa_port_notify(dp, DSA_NOTIFIER_HOST_FDB_DEL, &info);
}

int dsa_port_standalone_host_fdb_del(struct dsa_port *dp,
                                     const unsigned char *addr, u16 vid)
{
        struct dsa_db db = {
                .type = DSA_DB_PORT,
                .dp = dp,
        };

        return dsa_port_host_fdb_del(dp, addr, vid, db);
}

int dsa_port_bridge_host_fdb_del(struct dsa_port *dp,
                                 const unsigned char *addr, u16 vid)
{
        struct net_device *conduit = dsa_port_to_conduit(dp);
        struct dsa_db db = {
                .type = DSA_DB_BRIDGE,
                .bridge = *dp->bridge,
        };
        int err;

        if (!dp->ds->fdb_isolation)
                db.bridge.num = 0;

        if (conduit->priv_flags & IFF_UNICAST_FLT) {
                err = dev_uc_del(conduit, addr);
                if (err)
                        return err;
        }

        return dsa_port_host_fdb_del(dp, addr, vid, db);
}

int dsa_port_lag_fdb_add(struct dsa_port *dp, const unsigned char *addr,
                         u16 vid)
{
        struct dsa_notifier_lag_fdb_info info = {
                .lag = dp->lag,
                .addr = addr,
                .vid = vid,
                .db = {
                        .type = DSA_DB_BRIDGE,
                        .bridge = *dp->bridge,
                },
        };

        if (!dp->ds->fdb_isolation)
                info.db.bridge.num = 0;

        return dsa_port_notify(dp, DSA_NOTIFIER_LAG_FDB_ADD, &info);
}

int dsa_port_lag_fdb_del(struct dsa_port *dp, const unsigned char *addr,
                         u16 vid)
{
        struct dsa_notifier_lag_fdb_info info = {
                .lag = dp->lag,
                .addr = addr,
                .vid = vid,
                .db = {
                        .type = DSA_DB_BRIDGE,
                        .bridge = *dp->bridge,
                },
        };

        if (!dp->ds->fdb_isolation)
                info.db.bridge.num = 0;

        return dsa_port_notify(dp, DSA_NOTIFIER_LAG_FDB_DEL, &info);
}

int dsa_port_fdb_dump(struct dsa_port *dp, dsa_fdb_dump_cb_t *cb, void *data)
{
        struct dsa_switch *ds = dp->ds;
        int port = dp->index;

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

        return ds->ops->port_fdb_dump(ds, port, cb, data);
}

int dsa_port_mdb_add(const struct dsa_port *dp,
                     const struct switchdev_obj_port_mdb *mdb)
{
        struct dsa_notifier_mdb_info info = {
                .dp = dp,
                .mdb = mdb,
                .db = {
                        .type = DSA_DB_BRIDGE,
                        .bridge = *dp->bridge,
                },
        };

        if (!dp->ds->fdb_isolation)
                info.db.bridge.num = 0;

        return dsa_port_notify(dp, DSA_NOTIFIER_MDB_ADD, &info);
}

int dsa_port_mdb_del(const struct dsa_port *dp,
                     const struct switchdev_obj_port_mdb *mdb)
{
        struct dsa_notifier_mdb_info info = {
                .dp = dp,
                .mdb = mdb,
                .db = {
                        .type = DSA_DB_BRIDGE,
                        .bridge = *dp->bridge,
                },
        };

        if (!dp->ds->fdb_isolation)
                info.db.bridge.num = 0;

        return dsa_port_notify(dp, DSA_NOTIFIER_MDB_DEL, &info);
}

static int dsa_port_host_mdb_add(const struct dsa_port *dp,
                                 const struct switchdev_obj_port_mdb *mdb,
                                 struct dsa_db db)
{
        struct dsa_notifier_mdb_info info = {
                .dp = dp,
                .mdb = mdb,
                .db = db,
        };

        return dsa_port_notify(dp, DSA_NOTIFIER_HOST_MDB_ADD, &info);
}

int dsa_port_standalone_host_mdb_add(const struct dsa_port *dp,
                                     const struct switchdev_obj_port_mdb *mdb)
{
        struct dsa_db db = {
                .type = DSA_DB_PORT,
                .dp = dp,
        };

        return dsa_port_host_mdb_add(dp, mdb, db);
}

int dsa_port_bridge_host_mdb_add(const struct dsa_port *dp,
                                 const struct switchdev_obj_port_mdb *mdb)
{
        struct net_device *conduit = dsa_port_to_conduit(dp);
        struct dsa_db db = {
                .type = DSA_DB_BRIDGE,
                .bridge = *dp->bridge,
        };
        int err;

        if (!dp->ds->fdb_isolation)
                db.bridge.num = 0;

        err = dev_mc_add(conduit, mdb->addr);
        if (err)
                return err;

        return dsa_port_host_mdb_add(dp, mdb, db);
}

static int dsa_port_host_mdb_del(const struct dsa_port *dp,
                                 const struct switchdev_obj_port_mdb *mdb,
                                 struct dsa_db db)
{
        struct dsa_notifier_mdb_info info = {
                .dp = dp,
                .mdb = mdb,
                .db = db,
        };

        return dsa_port_notify(dp, DSA_NOTIFIER_HOST_MDB_DEL, &info);
}

int dsa_port_standalone_host_mdb_del(const struct dsa_port *dp,
                                     const struct switchdev_obj_port_mdb *mdb)
{
        struct dsa_db db = {
                .type = DSA_DB_PORT,
                .dp = dp,
        };

        return dsa_port_host_mdb_del(dp, mdb, db);
}

int dsa_port_bridge_host_mdb_del(const struct dsa_port *dp,
                                 const struct switchdev_obj_port_mdb *mdb)
{
        struct net_device *conduit = dsa_port_to_conduit(dp);
        struct dsa_db db = {
                .type = DSA_DB_BRIDGE,
                .bridge = *dp->bridge,
        };
        int err;

        if (!dp->ds->fdb_isolation)
                db.bridge.num = 0;

        err = dev_mc_del(conduit, mdb->addr);
        if (err)
                return err;

        return dsa_port_host_mdb_del(dp, mdb, db);
}

int dsa_port_vlan_add(struct dsa_port *dp,
                      const struct switchdev_obj_port_vlan *vlan,
                      struct netlink_ext_ack *extack)
{
        struct dsa_notifier_vlan_info info = {
                .dp = dp,
                .vlan = vlan,
                .extack = extack,
        };

        return dsa_port_notify(dp, DSA_NOTIFIER_VLAN_ADD, &info);
}

int dsa_port_vlan_del(struct dsa_port *dp,
                      const struct switchdev_obj_port_vlan *vlan)
{
        struct dsa_notifier_vlan_info info = {
                .dp = dp,
                .vlan = vlan,
        };

        return dsa_port_notify(dp, DSA_NOTIFIER_VLAN_DEL, &info);
}

int dsa_port_host_vlan_add(struct dsa_port *dp,
                           const struct switchdev_obj_port_vlan *vlan,
                           struct netlink_ext_ack *extack)
{
        struct net_device *conduit = dsa_port_to_conduit(dp);
        struct dsa_notifier_vlan_info info = {
                .dp = dp,
                .vlan = vlan,
                .extack = extack,
        };
        int err;

        err = dsa_port_notify(dp, DSA_NOTIFIER_HOST_VLAN_ADD, &info);
        if (err && err != -EOPNOTSUPP)
                return err;

        vlan_vid_add(conduit, htons(ETH_P_8021Q), vlan->vid);

        return err;
}

int dsa_port_host_vlan_del(struct dsa_port *dp,
                           const struct switchdev_obj_port_vlan *vlan)
{
        struct net_device *conduit = dsa_port_to_conduit(dp);
        struct dsa_notifier_vlan_info info = {
                .dp = dp,
                .vlan = vlan,
        };
        int err;

        err = dsa_port_notify(dp, DSA_NOTIFIER_HOST_VLAN_DEL, &info);
        if (err && err != -EOPNOTSUPP)
                return err;

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

        return err;
}

int dsa_port_mrp_add(const struct dsa_port *dp,
                     const struct switchdev_obj_mrp *mrp)
{
        struct dsa_switch *ds = dp->ds;

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

        return ds->ops->port_mrp_add(ds, dp->index, mrp);
}

int dsa_port_mrp_del(const struct dsa_port *dp,
                     const struct switchdev_obj_mrp *mrp)
{
        struct dsa_switch *ds = dp->ds;

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

        return ds->ops->port_mrp_del(ds, dp->index, mrp);
}

int dsa_port_mrp_add_ring_role(const struct dsa_port *dp,
                               const struct switchdev_obj_ring_role_mrp *mrp)
{
        struct dsa_switch *ds = dp->ds;

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

        return ds->ops->port_mrp_add_ring_role(ds, dp->index, mrp);
}

int dsa_port_mrp_del_ring_role(const struct dsa_port *dp,
                               const struct switchdev_obj_ring_role_mrp *mrp)
{
        struct dsa_switch *ds = dp->ds;

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

        return ds->ops->port_mrp_del_ring_role(ds, dp->index, mrp);
}

static int dsa_port_assign_conduit(struct dsa_port *dp,
                                   struct net_device *conduit,
                                   struct netlink_ext_ack *extack,
                                   bool fail_on_err)
{
        struct dsa_switch *ds = dp->ds;
        int port = dp->index, err;

        err = ds->ops->port_change_conduit(ds, port, conduit, extack);
        if (err && !fail_on_err)
                dev_err(ds->dev, "port %d failed to assign conduit %s: %pe\n",
                        port, conduit->name, ERR_PTR(err));

        if (err && fail_on_err)
                return err;

        dp->cpu_dp = conduit->dsa_ptr;
        dp->cpu_port_in_lag = netif_is_lag_master(conduit);

        return 0;
}

/* Change the dp->cpu_dp affinity for a user port. Note that both cross-chip
 * notifiers and drivers have implicit assumptions about user-to-CPU-port
 * mappings, so we unfortunately cannot delay the deletion of the objects
 * (switchdev, standalone addresses, standalone VLANs) on the old CPU port
 * until the new CPU port has been set up. So we need to completely tear down
 * the old CPU port before changing it, and restore it on errors during the
 * bringup of the new one.
 */
int dsa_port_change_conduit(struct dsa_port *dp, struct net_device *conduit,
                            struct netlink_ext_ack *extack)
{
        struct net_device *bridge_dev = dsa_port_bridge_dev_get(dp);
        struct net_device *old_conduit = dsa_port_to_conduit(dp);
        struct net_device *dev = dp->user;
        struct dsa_switch *ds = dp->ds;
        bool vlan_filtering;
        int err, tmp;

        /* Bridges may hold host FDB, MDB and VLAN objects. These need to be
         * migrated, so dynamically unoffload and later reoffload the bridge
         * port.
         */
        if (bridge_dev) {
                dsa_port_pre_bridge_leave(dp, bridge_dev);
                dsa_port_bridge_leave(dp, bridge_dev);
        }

        /* The port might still be VLAN filtering even if it's no longer
         * under a bridge, either due to ds->vlan_filtering_is_global or
         * ds->needs_standalone_vlan_filtering. In turn this means VLANs
         * on the CPU port.
         */
        vlan_filtering = dsa_port_is_vlan_filtering(dp);
        if (vlan_filtering) {
                err = dsa_user_manage_vlan_filtering(dev, false);
                if (err) {
                        NL_SET_ERR_MSG_MOD(extack,
                                           "Failed to remove standalone VLANs");
                        goto rewind_old_bridge;
                }
        }

        /* Standalone addresses, and addresses of upper interfaces like
         * VLAN, LAG, HSR need to be migrated.
         */
        dsa_user_unsync_ha(dev);

        /* If live-changing, we also need to uninstall the user device address
         * from the port FDB and the conduit interface.
         */
        if (dev->flags & IFF_UP)
                dsa_user_host_uc_uninstall(dev);

        err = dsa_port_assign_conduit(dp, conduit, extack, true);
        if (err)
                goto rewind_old_addrs;

        /* If the port doesn't have its own MAC address and relies on the DSA
         * conduit's one, inherit it again from the new DSA conduit.
         */
        if (is_zero_ether_addr(dp->mac))
                eth_hw_addr_inherit(dev, conduit);

        /* If live-changing, we need to install the user device address to the
         * port FDB and the conduit interface.
         */
        if (dev->flags & IFF_UP) {
                err = dsa_user_host_uc_install(dev, dev->dev_addr);
                if (err) {
                        NL_SET_ERR_MSG_MOD(extack,
                                           "Failed to install host UC address");
                        goto rewind_addr_inherit;
                }
        }

        dsa_user_sync_ha(dev);

        if (vlan_filtering) {
                err = dsa_user_manage_vlan_filtering(dev, true);
                if (err) {
                        NL_SET_ERR_MSG_MOD(extack,
                                           "Failed to restore standalone VLANs");
                        goto rewind_new_addrs;
                }
        }

        if (bridge_dev) {
                err = dsa_port_bridge_join(dp, bridge_dev, extack);
                if (err && err == -EOPNOTSUPP) {
                        NL_SET_ERR_MSG_MOD(extack,
                                           "Failed to reoffload bridge");
                        goto rewind_new_vlan;
                }
        }

        return 0;

rewind_new_vlan:
        if (vlan_filtering)
                dsa_user_manage_vlan_filtering(dev, false);

rewind_new_addrs:
        dsa_user_unsync_ha(dev);

        if (dev->flags & IFF_UP)
                dsa_user_host_uc_uninstall(dev);

rewind_addr_inherit:
        if (is_zero_ether_addr(dp->mac))
                eth_hw_addr_inherit(dev, old_conduit);

        dsa_port_assign_conduit(dp, old_conduit, NULL, false);

/* Restore the objects on the old CPU port */
rewind_old_addrs:
        if (dev->flags & IFF_UP) {
                tmp = dsa_user_host_uc_install(dev, dev->dev_addr);
                if (tmp) {
                        dev_err(ds->dev,
                                "port %d failed to restore host UC address: %pe\n",
                                dp->index, ERR_PTR(tmp));
                }
        }

        dsa_user_sync_ha(dev);

        if (vlan_filtering) {
                tmp = dsa_user_manage_vlan_filtering(dev, true);
                if (tmp) {
                        dev_err(ds->dev,
                                "port %d failed to restore standalone VLANs: %pe\n",
                                dp->index, ERR_PTR(tmp));
                }
        }

rewind_old_bridge:
        if (bridge_dev) {
                tmp = dsa_port_bridge_join(dp, bridge_dev, extack);
                if (tmp) {
                        dev_err(ds->dev,
                                "port %d failed to rejoin bridge %s: %pe\n",
                                dp->index, bridge_dev->name, ERR_PTR(tmp));
                }
        }

        return err;
}

void dsa_port_set_tag_protocol(struct dsa_port *cpu_dp,
                               const struct dsa_device_ops *tag_ops)
{
        cpu_dp->rcv = tag_ops->rcv;
        cpu_dp->tag_ops = tag_ops;
}

/* dsa_supports_eee - indicate that EEE is supported
 * @ds: pointer to &struct dsa_switch
 * @port: port index
 *
 * A default implementation for the .support_eee() DSA operations member,
 * which drivers can use to indicate that they support EEE on all of their
 * user ports.
 *
 * Returns: true
 */
bool dsa_supports_eee(struct dsa_switch *ds, int port)
{
        return true;
}
EXPORT_SYMBOL_GPL(dsa_supports_eee);

static void dsa_port_phylink_mac_config(struct phylink_config *config,
                                        unsigned int mode,
                                        const struct phylink_link_state *state)
{
}

static void dsa_port_phylink_mac_link_down(struct phylink_config *config,
                                           unsigned int mode,
                                           phy_interface_t interface)
{
}

static void dsa_port_phylink_mac_link_up(struct phylink_config *config,
                                         struct phy_device *phydev,
                                         unsigned int mode,
                                         phy_interface_t interface,
                                         int speed, int duplex,
                                         bool tx_pause, bool rx_pause)
{
}

static const struct phylink_mac_ops dsa_port_phylink_mac_ops = {
        .mac_config = dsa_port_phylink_mac_config,
        .mac_link_down = dsa_port_phylink_mac_link_down,
        .mac_link_up = dsa_port_phylink_mac_link_up,
};

int dsa_port_phylink_create(struct dsa_port *dp)
{
        const struct phylink_mac_ops *mac_ops;
        struct dsa_switch *ds = dp->ds;
        phy_interface_t mode;
        struct phylink *pl;
        int err;

        err = of_get_phy_mode(dp->dn, &mode);
        if (err)
                mode = PHY_INTERFACE_MODE_NA;

        if (ds->ops->phylink_get_caps) {
                ds->ops->phylink_get_caps(ds, dp->index, &dp->pl_config);
        } else {
                /* For legacy drivers */
                if (mode != PHY_INTERFACE_MODE_NA) {
                        __set_bit(mode, dp->pl_config.supported_interfaces);
                } else {
                        __set_bit(PHY_INTERFACE_MODE_INTERNAL,
                                  dp->pl_config.supported_interfaces);
                        __set_bit(PHY_INTERFACE_MODE_GMII,
                                  dp->pl_config.supported_interfaces);
                }
        }

        mac_ops = &dsa_port_phylink_mac_ops;
        if (ds->phylink_mac_ops)
                mac_ops = ds->phylink_mac_ops;

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

        dp->pl = pl;

        return 0;
}

void dsa_port_phylink_destroy(struct dsa_port *dp)
{
        phylink_destroy(dp->pl);
        dp->pl = NULL;
}

static int dsa_shared_port_phylink_register(struct dsa_port *dp)
{
        struct dsa_switch *ds = dp->ds;
        struct device_node *port_dn = dp->dn;
        int err;

        dp->pl_config.dev = ds->dev;
        dp->pl_config.type = PHYLINK_DEV;

        err = dsa_port_phylink_create(dp);
        if (err)
                return err;

        err = phylink_of_phy_connect(dp->pl, port_dn, 0);
        if (err && err != -ENODEV) {
                pr_err("could not attach to PHY: %d\n", err);
                goto err_phy_connect;
        }

        return 0;

err_phy_connect:
        dsa_port_phylink_destroy(dp);
        return err;
}

/* During the initial DSA driver migration to OF, port nodes were sometimes
 * added to device trees with no indication of how they should operate from a
 * link management perspective (phy-handle, fixed-link, etc). Additionally, the
 * phy-mode may be absent. The interpretation of these port OF nodes depends on
 * their type.
 *
 * User ports with no phy-handle or fixed-link are expected to connect to an
 * internal PHY located on the ds->user_mii_bus at an MDIO address equal to
 * the port number. This description is still actively supported.
 *
 * Shared (CPU and DSA) ports with no phy-handle or fixed-link are expected to
 * operate at the maximum speed that their phy-mode is capable of. If the
 * phy-mode is absent, they are expected to operate using the phy-mode
 * supported by the port that gives the highest link speed. It is unspecified
 * if the port should use flow control or not, half duplex or full duplex, or
 * if the phy-mode is a SERDES link, whether in-band autoneg is expected to be
 * enabled or not.
 *
 * In the latter case of shared ports, omitting the link management description
 * from the firmware node is deprecated and strongly discouraged. DSA uses
 * phylink, which rejects the firmware nodes of these ports for lacking
 * required properties.
 *
 * For switches in this table, DSA will skip enforcing validation and will
 * later omit registering a phylink instance for the shared ports, if they lack
 * a fixed-link, a phy-handle, or a managed = "in-band-status" property.
 * It becomes the responsibility of the driver to ensure that these ports
 * operate at the maximum speed (whatever this means) and will interoperate
 * with the DSA conduit or other cascade port, since phylink methods will not be
 * invoked for them.
 *
 * If you are considering expanding this table for newly introduced switches,
 * think again. It is OK to remove switches from this table if there aren't DT
 * blobs in circulation which rely on defaulting the shared ports.
 */
static const char * const dsa_switches_apply_workarounds[] = {
#if IS_ENABLED(CONFIG_NET_DSA_XRS700X)
        "arrow,xrs7003e",
        "arrow,xrs7003f",
        "arrow,xrs7004e",
        "arrow,xrs7004f",
#endif
#if IS_ENABLED(CONFIG_B53)
        "brcm,bcm5325",
        "brcm,bcm53115",
        "brcm,bcm53125",
        "brcm,bcm53128",
        "brcm,bcm5365",
        "brcm,bcm5389",
        "brcm,bcm5395",
        "brcm,bcm5397",
        "brcm,bcm5398",
        "brcm,bcm53010-srab",
        "brcm,bcm53011-srab",
        "brcm,bcm53012-srab",
        "brcm,bcm53018-srab",
        "brcm,bcm53019-srab",
        "brcm,bcm5301x-srab",
        "brcm,bcm11360-srab",
        "brcm,bcm58522-srab",
        "brcm,bcm58525-srab",
        "brcm,bcm58535-srab",
        "brcm,bcm58622-srab",
        "brcm,bcm58623-srab",
        "brcm,bcm58625-srab",
        "brcm,bcm88312-srab",
        "brcm,cygnus-srab",
        "brcm,nsp-srab",
        "brcm,omega-srab",
        "brcm,bcm3384-switch",
        "brcm,bcm6328-switch",
        "brcm,bcm6368-switch",
        "brcm,bcm63xx-switch",
#endif
#if IS_ENABLED(CONFIG_NET_DSA_BCM_SF2)
        "brcm,bcm7445-switch-v4.0",
        "brcm,bcm7278-switch-v4.0",
        "brcm,bcm7278-switch-v4.8",
#endif
#if IS_ENABLED(CONFIG_NET_DSA_LANTIQ_GSWIP)
        "lantiq,xrx200-gswip",
        "lantiq,xrx300-gswip",
        "lantiq,xrx330-gswip",
#endif
#if IS_ENABLED(CONFIG_NET_DSA_MV88E6060)
        "marvell,mv88e6060",
#endif
#if IS_ENABLED(CONFIG_NET_DSA_MV88E6XXX)
        "marvell,mv88e6085",
        "marvell,mv88e6190",
        "marvell,mv88e6250",
#endif
#if IS_ENABLED(CONFIG_NET_DSA_MICROCHIP_KSZ_COMMON)
        "microchip,ksz8765",
        "microchip,ksz8794",
        "microchip,ksz8795",
        "microchip,ksz8863",
        "microchip,ksz8873",
        "microchip,ksz9477",
        "microchip,ksz9897",
        "microchip,ksz9893",
        "microchip,ksz9563",
        "microchip,ksz8563",
        "microchip,ksz9567",
#endif
#if IS_ENABLED(CONFIG_NET_DSA_SMSC_LAN9303_MDIO)
        "smsc,lan9303-mdio",
#endif
#if IS_ENABLED(CONFIG_NET_DSA_SMSC_LAN9303_I2C)
        "smsc,lan9303-i2c",
#endif
        NULL,
};

static void dsa_shared_port_validate_of(struct dsa_port *dp,
                                        bool *missing_phy_mode,
                                        bool *missing_link_description)
{
        struct device_node *dn = dp->dn, *phy_np;
        struct dsa_switch *ds = dp->ds;
        phy_interface_t mode;

        *missing_phy_mode = false;
        *missing_link_description = false;

        if (of_get_phy_mode(dn, &mode)) {
                *missing_phy_mode = true;
                dev_err(ds->dev,
                        "OF node %pOF of %s port %d lacks the required \"phy-mode\" property\n",
                        dn, dsa_port_is_cpu(dp) ? "CPU" : "DSA", dp->index);
        }

        /* Note: of_phy_is_fixed_link() also returns true for
         * managed = "in-band-status"
         */
        if (of_phy_is_fixed_link(dn))
                return;

        phy_np = of_parse_phandle(dn, "phy-handle", 0);
        if (phy_np) {
                of_node_put(phy_np);
                return;
        }

        *missing_link_description = true;

        dev_err(ds->dev,
                "OF node %pOF of %s port %d lacks the required \"phy-handle\", \"fixed-link\" or \"managed\" properties\n",
                dn, dsa_port_is_cpu(dp) ? "CPU" : "DSA", dp->index);
}

static void dsa_shared_port_link_down(struct dsa_port *dp)
{
        struct dsa_switch *ds = dp->ds;

        if (ds->phylink_mac_ops && ds->phylink_mac_ops->mac_link_down)
                ds->phylink_mac_ops->mac_link_down(&dp->pl_config, MLO_AN_FIXED,
                                                   PHY_INTERFACE_MODE_NA);
}

int dsa_shared_port_link_register_of(struct dsa_port *dp)
{
        struct dsa_switch *ds = dp->ds;
        bool missing_link_description;
        bool missing_phy_mode;

        dsa_shared_port_validate_of(dp, &missing_phy_mode,
                                    &missing_link_description);

        if ((missing_phy_mode || missing_link_description) &&
            !of_device_compatible_match(ds->dev->of_node,
                                        dsa_switches_apply_workarounds))
                return -EINVAL;

        if (missing_link_description) {
                dev_warn(ds->dev,
                         "Skipping phylink registration for %s port %d\n",
                         dsa_port_is_cpu(dp) ? "CPU" : "DSA", dp->index);
        } else {
                dsa_shared_port_link_down(dp);

                return dsa_shared_port_phylink_register(dp);
        }

        return 0;
}

void dsa_shared_port_link_unregister_of(struct dsa_port *dp)
{
        if (dp->pl) {
                rtnl_lock();
                phylink_disconnect_phy(dp->pl);
                rtnl_unlock();
                dsa_port_phylink_destroy(dp);
                return;
        }
}

int dsa_port_hsr_join(struct dsa_port *dp, struct net_device *hsr,
                      struct netlink_ext_ack *extack)
{
        struct dsa_switch *ds = dp->ds;
        int err;

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

        dp->hsr_dev = hsr;

        err = ds->ops->port_hsr_join(ds, dp->index, hsr, extack);
        if (err)
                dp->hsr_dev = NULL;

        return err;
}

void dsa_port_hsr_leave(struct dsa_port *dp, struct net_device *hsr)
{
        struct dsa_switch *ds = dp->ds;
        int err;

        if (!dp->hsr_dev)
                return;

        dp->hsr_dev = NULL;

        if (ds->ops->port_hsr_leave) {
                err = ds->ops->port_hsr_leave(ds, dp->index, hsr);
                if (err)
                        dev_err(dp->ds->dev,
                                "port %d failed to leave HSR %s: %pe\n",
                                dp->index, hsr->name, ERR_PTR(err));
        }
}

int dsa_port_tag_8021q_vlan_add(struct dsa_port *dp, u16 vid, bool broadcast)
{
        struct dsa_notifier_tag_8021q_vlan_info info = {
                .dp = dp,
                .vid = vid,
        };

        if (broadcast)
                return dsa_broadcast(DSA_NOTIFIER_TAG_8021Q_VLAN_ADD, &info);

        return dsa_port_notify(dp, DSA_NOTIFIER_TAG_8021Q_VLAN_ADD, &info);
}

void dsa_port_tag_8021q_vlan_del(struct dsa_port *dp, u16 vid, bool broadcast)
{
        struct dsa_notifier_tag_8021q_vlan_info info = {
                .dp = dp,
                .vid = vid,
        };
        int err;

        if (broadcast)
                err = dsa_broadcast(DSA_NOTIFIER_TAG_8021Q_VLAN_DEL, &info);
        else
                err = dsa_port_notify(dp, DSA_NOTIFIER_TAG_8021Q_VLAN_DEL, &info);
        if (err)
                dev_err(dp->ds->dev,
                        "port %d failed to notify tag_8021q VLAN %d deletion: %pe\n",
                        dp->index, vid, ERR_PTR(err));
}