// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * DSA topology and switch handling
 *
 * Copyright (c) 2008-2009 Marvell Semiconductor
 * Copyright (c) 2013 Florian Fainelli <florian@openwrt.org>
 * Copyright (c) 2016 Andrew Lunn <andrew@lunn.ch>
 */

#include <linux/device.h>
#include <linux/err.h>
#include <linux/if_hsr.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/netdevice.h>
#include <linux/slab.h>
#include <linux/rtnetlink.h>
#include <linux/of.h>
#include <linux/of_net.h>
#include <net/dsa_stubs.h>
#include <net/sch_generic.h>

#include "conduit.h"
#include "devlink.h"
#include "dsa.h"
#include "netlink.h"
#include "port.h"
#include "switch.h"
#include "tag.h"
#include "user.h"

#define DSA_MAX_NUM_OFFLOADING_BRIDGES          BITS_PER_LONG

static DEFINE_MUTEX(dsa2_mutex);
LIST_HEAD(dsa_tree_list);

static struct workqueue_struct *dsa_owq;

/* Track the bridges with forwarding offload enabled */
static unsigned long dsa_fwd_offloading_bridges;

bool dsa_schedule_work(struct work_struct *work)
{
        return queue_work(dsa_owq, work);
}

void dsa_flush_workqueue(void)
{
        flush_workqueue(dsa_owq);
}
EXPORT_SYMBOL_GPL(dsa_flush_workqueue);

/**
 * dsa_lag_map() - Map LAG structure to a linear LAG array
 * @dst: Tree in which to record the mapping.
 * @lag: LAG structure that is to be mapped to the tree's array.
 *
 * dsa_lag_id/dsa_lag_by_id can then be used to translate between the
 * two spaces. The size of the mapping space is determined by the
 * driver by setting ds->num_lag_ids. It is perfectly legal to leave
 * it unset if it is not needed, in which case these functions become
 * no-ops.
 */
void dsa_lag_map(struct dsa_switch_tree *dst, struct dsa_lag *lag)
{
        unsigned int id;

        for (id = 1; id <= dst->lags_len; id++) {
                if (!dsa_lag_by_id(dst, id)) {
                        dst->lags[id - 1] = lag;
                        lag->id = id;
                        return;
                }
        }

        /* No IDs left, which is OK. Some drivers do not need it. The
         * ones that do, e.g. mv88e6xxx, will discover that dsa_lag_id
         * returns an error for this device when joining the LAG. The
         * driver can then return -EOPNOTSUPP back to DSA, which will
         * fall back to a software LAG.
         */
}

/**
 * dsa_lag_unmap() - Remove a LAG ID mapping
 * @dst: Tree in which the mapping is recorded.
 * @lag: LAG structure that was mapped.
 *
 * As there may be multiple users of the mapping, it is only removed
 * if there are no other references to it.
 */
void dsa_lag_unmap(struct dsa_switch_tree *dst, struct dsa_lag *lag)
{
        unsigned int id;

        dsa_lags_foreach_id(id, dst) {
                if (dsa_lag_by_id(dst, id) == lag) {
                        dst->lags[id - 1] = NULL;
                        lag->id = 0;
                        break;
                }
        }
}

struct dsa_lag *dsa_tree_lag_find(struct dsa_switch_tree *dst,
                                  const struct net_device *lag_dev)
{
        struct dsa_port *dp;

        list_for_each_entry(dp, &dst->ports, list)
                if (dsa_port_lag_dev_get(dp) == lag_dev)
                        return dp->lag;

        return NULL;
}

struct dsa_bridge *dsa_tree_bridge_find(struct dsa_switch_tree *dst,
                                        const struct net_device *br)
{
        struct dsa_port *dp;

        list_for_each_entry(dp, &dst->ports, list)
                if (dsa_port_bridge_dev_get(dp) == br)
                        return dp->bridge;

        return NULL;
}

static int dsa_bridge_num_find(const struct net_device *bridge_dev)
{
        struct dsa_switch_tree *dst;

        list_for_each_entry(dst, &dsa_tree_list, list) {
                struct dsa_bridge *bridge;

                bridge = dsa_tree_bridge_find(dst, bridge_dev);
                if (bridge)
                        return bridge->num;
        }

        return 0;
}

unsigned int dsa_bridge_num_get(const struct net_device *bridge_dev, int max)
{
        unsigned int bridge_num = dsa_bridge_num_find(bridge_dev);

        /* Switches without FDB isolation support don't get unique
         * bridge numbering
         */
        if (!max)
                return 0;

        if (!bridge_num) {
                /* First port that requests FDB isolation or TX forwarding
                 * offload for this bridge
                 */
                bridge_num = find_next_zero_bit(&dsa_fwd_offloading_bridges,
                                                DSA_MAX_NUM_OFFLOADING_BRIDGES,
                                                1);
                if (bridge_num > max)
                        return 0;

                set_bit(bridge_num, &dsa_fwd_offloading_bridges);
        }

        return bridge_num;
}

void dsa_bridge_num_put(const struct net_device *bridge_dev,
                        unsigned int bridge_num)
{
        /* Since we refcount bridges, we know that when we call this function
         * it is no longer in use, so we can just go ahead and remove it from
         * the bit mask.
         */
        clear_bit(bridge_num, &dsa_fwd_offloading_bridges);
}

struct dsa_switch *dsa_switch_find(int tree_index, int sw_index)
{
        struct dsa_switch_tree *dst;
        struct dsa_port *dp;

        list_for_each_entry(dst, &dsa_tree_list, list) {
                if (dst->index != tree_index)
                        continue;

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

                        return dp->ds;
                }
        }

        return NULL;
}
EXPORT_SYMBOL_GPL(dsa_switch_find);

static struct dsa_switch_tree *dsa_tree_find(int index)
{
        struct dsa_switch_tree *dst;

        list_for_each_entry(dst, &dsa_tree_list, list)
                if (dst->index == index)
                        return dst;

        return NULL;
}

static struct dsa_switch_tree *dsa_tree_alloc(int index)
{
        struct dsa_switch_tree *dst;

        dst = kzalloc_obj(*dst);
        if (!dst)
                return NULL;

        dst->index = index;

        INIT_LIST_HEAD(&dst->rtable);

        INIT_LIST_HEAD(&dst->ports);

        INIT_LIST_HEAD(&dst->list);
        list_add_tail(&dst->list, &dsa_tree_list);

        kref_init(&dst->refcount);

        return dst;
}

static void dsa_tree_free(struct dsa_switch_tree *dst)
{
        if (dst->tag_ops)
                dsa_tag_driver_put(dst->tag_ops);
        list_del(&dst->list);
        kfree(dst);
}

static struct dsa_switch_tree *dsa_tree_get(struct dsa_switch_tree *dst)
{
        if (dst)
                kref_get(&dst->refcount);

        return dst;
}

static struct dsa_switch_tree *dsa_tree_touch(int index)
{
        struct dsa_switch_tree *dst;

        dst = dsa_tree_find(index);
        if (dst)
                return dsa_tree_get(dst);
        else
                return dsa_tree_alloc(index);
}

static void dsa_tree_release(struct kref *ref)
{
        struct dsa_switch_tree *dst;

        dst = container_of(ref, struct dsa_switch_tree, refcount);

        dsa_tree_free(dst);
}

static void dsa_tree_put(struct dsa_switch_tree *dst)
{
        if (dst)
                kref_put(&dst->refcount, dsa_tree_release);
}

static struct dsa_port *dsa_tree_find_port_by_node(struct dsa_switch_tree *dst,
                                                   struct device_node *dn)
{
        struct dsa_port *dp;

        list_for_each_entry(dp, &dst->ports, list)
                if (dp->dn == dn)
                        return dp;

        return NULL;
}

static struct dsa_link *dsa_link_touch(struct dsa_port *dp,
                                       struct dsa_port *link_dp)
{
        struct dsa_switch *ds = dp->ds;
        struct dsa_switch_tree *dst;
        struct dsa_link *dl;

        dst = ds->dst;

        list_for_each_entry(dl, &dst->rtable, list)
                if (dl->dp == dp && dl->link_dp == link_dp)
                        return dl;

        dl = kzalloc_obj(*dl);
        if (!dl)
                return NULL;

        dl->dp = dp;
        dl->link_dp = link_dp;

        INIT_LIST_HEAD(&dl->list);
        list_add_tail(&dl->list, &dst->rtable);

        return dl;
}

static bool dsa_port_setup_routing_table(struct dsa_port *dp)
{
        struct dsa_switch *ds = dp->ds;
        struct dsa_switch_tree *dst = ds->dst;
        struct device_node *dn = dp->dn;
        struct of_phandle_iterator it;
        struct dsa_port *link_dp;
        struct dsa_link *dl;
        int err;

        of_for_each_phandle(&it, err, dn, "link", NULL, 0) {
                link_dp = dsa_tree_find_port_by_node(dst, it.node);
                if (!link_dp) {
                        of_node_put(it.node);
                        return false;
                }

                dl = dsa_link_touch(dp, link_dp);
                if (!dl) {
                        of_node_put(it.node);
                        return false;
                }
        }

        return true;
}

static bool dsa_tree_setup_routing_table(struct dsa_switch_tree *dst)
{
        bool complete = true;
        struct dsa_port *dp;

        list_for_each_entry(dp, &dst->ports, list) {
                if (dsa_port_is_dsa(dp)) {
                        complete = dsa_port_setup_routing_table(dp);
                        if (!complete)
                                break;
                }
        }

        return complete;
}

static struct dsa_port *dsa_tree_find_first_cpu(struct dsa_switch_tree *dst)
{
        struct dsa_port *dp;

        list_for_each_entry(dp, &dst->ports, list)
                if (dsa_port_is_cpu(dp))
                        return dp;

        return NULL;
}

struct net_device *dsa_tree_find_first_conduit(struct dsa_switch_tree *dst)
{
        struct dsa_port *cpu_dp;

        cpu_dp = dsa_tree_find_first_cpu(dst);
        return cpu_dp->conduit;
}

/* Assign the default CPU port (the first one in the tree) to all ports of the
 * fabric which don't already have one as part of their own switch.
 */
static int dsa_tree_setup_default_cpu(struct dsa_switch_tree *dst)
{
        struct dsa_port *cpu_dp, *dp;

        cpu_dp = dsa_tree_find_first_cpu(dst);
        if (!cpu_dp) {
                pr_err("DSA: tree %d has no CPU port\n", dst->index);
                return -EINVAL;
        }

        list_for_each_entry(dp, &dst->ports, list) {
                if (dp->cpu_dp)
                        continue;

                if (dsa_port_is_user(dp) || dsa_port_is_dsa(dp))
                        dp->cpu_dp = cpu_dp;
        }

        return 0;
}

static struct dsa_port *
dsa_switch_preferred_default_local_cpu_port(struct dsa_switch *ds)
{
        struct dsa_port *cpu_dp;

        if (!ds->ops->preferred_default_local_cpu_port)
                return NULL;

        cpu_dp = ds->ops->preferred_default_local_cpu_port(ds);
        if (!cpu_dp)
                return NULL;

        if (WARN_ON(!dsa_port_is_cpu(cpu_dp) || cpu_dp->ds != ds))
                return NULL;

        return cpu_dp;
}

/* Perform initial assignment of CPU ports to user ports and DSA links in the
 * fabric, giving preference to CPU ports local to each switch. Default to
 * using the first CPU port in the switch tree if the port does not have a CPU
 * port local to this switch.
 */
static int dsa_tree_setup_cpu_ports(struct dsa_switch_tree *dst)
{
        struct dsa_port *preferred_cpu_dp, *cpu_dp, *dp;

        list_for_each_entry(cpu_dp, &dst->ports, list) {
                if (!dsa_port_is_cpu(cpu_dp))
                        continue;

                preferred_cpu_dp = dsa_switch_preferred_default_local_cpu_port(cpu_dp->ds);
                if (preferred_cpu_dp && preferred_cpu_dp != cpu_dp)
                        continue;

                /* Prefer a local CPU port */
                dsa_switch_for_each_port(dp, cpu_dp->ds) {
                        /* Prefer the first local CPU port found */
                        if (dp->cpu_dp)
                                continue;

                        if (dsa_port_is_user(dp) || dsa_port_is_dsa(dp))
                                dp->cpu_dp = cpu_dp;
                }
        }

        return dsa_tree_setup_default_cpu(dst);
}

static void dsa_tree_teardown_cpu_ports(struct dsa_switch_tree *dst)
{
        struct dsa_port *dp;

        list_for_each_entry(dp, &dst->ports, list)
                if (dsa_port_is_user(dp) || dsa_port_is_dsa(dp))
                        dp->cpu_dp = NULL;
}

static int dsa_port_setup(struct dsa_port *dp)
{
        bool dsa_port_link_registered = false;
        struct dsa_switch *ds = dp->ds;
        bool dsa_port_enabled = false;
        int err = 0;

        if (dp->setup)
                return 0;

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

        switch (dp->type) {
        case DSA_PORT_TYPE_UNUSED:
                dsa_port_disable(dp);
                break;
        case DSA_PORT_TYPE_CPU:
                if (dp->dn) {
                        err = dsa_shared_port_link_register_of(dp);
                        if (err)
                                break;
                        dsa_port_link_registered = true;
                } else {
                        dev_warn(ds->dev,
                                 "skipping link registration for CPU port %d\n",
                                 dp->index);
                }

                err = dsa_port_enable(dp, NULL);
                if (err)
                        break;
                dsa_port_enabled = true;

                break;
        case DSA_PORT_TYPE_DSA:
                if (dp->dn) {
                        err = dsa_shared_port_link_register_of(dp);
                        if (err)
                                break;
                        dsa_port_link_registered = true;
                } else {
                        dev_warn(ds->dev,
                                 "skipping link registration for DSA port %d\n",
                                 dp->index);
                }

                err = dsa_port_enable(dp, NULL);
                if (err)
                        break;
                dsa_port_enabled = true;

                break;
        case DSA_PORT_TYPE_USER:
                of_get_mac_address(dp->dn, dp->mac);
                err = dsa_user_create(dp);
                break;
        }

        if (err && dsa_port_enabled)
                dsa_port_disable(dp);
        if (err && dsa_port_link_registered)
                dsa_shared_port_link_unregister_of(dp);
        if (err) {
                dsa_port_devlink_teardown(dp);
                return err;
        }

        dp->setup = true;

        return 0;
}

static void dsa_port_teardown(struct dsa_port *dp)
{
        if (!dp->setup)
                return;

        switch (dp->type) {
        case DSA_PORT_TYPE_UNUSED:
                break;
        case DSA_PORT_TYPE_CPU:
                dsa_port_disable(dp);
                if (dp->dn)
                        dsa_shared_port_link_unregister_of(dp);
                break;
        case DSA_PORT_TYPE_DSA:
                dsa_port_disable(dp);
                if (dp->dn)
                        dsa_shared_port_link_unregister_of(dp);
                break;
        case DSA_PORT_TYPE_USER:
                if (dp->user) {
                        dsa_user_destroy(dp->user);
                        dp->user = NULL;
                }
                break;
        }

        dsa_port_devlink_teardown(dp);

        dp->setup = false;
}

static int dsa_port_setup_as_unused(struct dsa_port *dp)
{
        dp->type = DSA_PORT_TYPE_UNUSED;
        return dsa_port_setup(dp);
}

static int dsa_switch_setup_tag_protocol(struct dsa_switch *ds)
{
        const struct dsa_device_ops *tag_ops = ds->dst->tag_ops;
        struct dsa_switch_tree *dst = ds->dst;
        int err;

        if (tag_ops->proto == dst->default_proto)
                goto connect;

        rtnl_lock();
        err = ds->ops->change_tag_protocol(ds, tag_ops->proto);
        rtnl_unlock();
        if (err) {
                dev_err(ds->dev, "Unable to use tag protocol \"%s\": %pe\n",
                        tag_ops->name, ERR_PTR(err));
                return err;
        }

connect:
        if (tag_ops->connect) {
                err = tag_ops->connect(ds);
                if (err)
                        return err;
        }

        if (ds->ops->connect_tag_protocol) {
                err = ds->ops->connect_tag_protocol(ds, tag_ops->proto);
                if (err) {
                        dev_err(ds->dev,
                                "Unable to connect to tag protocol \"%s\": %pe\n",
                                tag_ops->name, ERR_PTR(err));
                        goto disconnect;
                }
        }

        return 0;

disconnect:
        if (tag_ops->disconnect)
                tag_ops->disconnect(ds);

        return err;
}

static void dsa_switch_teardown_tag_protocol(struct dsa_switch *ds)
{
        const struct dsa_device_ops *tag_ops = ds->dst->tag_ops;

        if (tag_ops->disconnect)
                tag_ops->disconnect(ds);
}

static int dsa_switch_setup(struct dsa_switch *ds)
{
        int err;

        if (ds->setup)
                return 0;

        /* Initialize ds->phys_mii_mask before registering the user MDIO bus
         * driver and before ops->setup() has run, since the switch drivers and
         * the user MDIO bus driver rely on these values for probing PHY
         * devices or not
         */
        ds->phys_mii_mask |= dsa_user_ports(ds);

        err = dsa_switch_devlink_alloc(ds);
        if (err)
                return err;

        err = dsa_switch_register_notifier(ds);
        if (err)
                goto devlink_free;

        ds->configure_vlan_while_not_filtering = true;

        err = ds->ops->setup(ds);
        if (err < 0)
                goto unregister_notifier;

        err = dsa_switch_setup_tag_protocol(ds);
        if (err)
                goto teardown;

        if (!ds->user_mii_bus && ds->ops->phy_read) {
                ds->user_mii_bus = mdiobus_alloc();
                if (!ds->user_mii_bus) {
                        err = -ENOMEM;
                        goto teardown;
                }

                dsa_user_mii_bus_init(ds);

                err = mdiobus_register(ds->user_mii_bus);
                if (err < 0)
                        goto free_user_mii_bus;
        }

        dsa_switch_devlink_register(ds);

        ds->setup = true;
        return 0;

free_user_mii_bus:
        if (ds->user_mii_bus && ds->ops->phy_read)
                mdiobus_free(ds->user_mii_bus);
teardown:
        if (ds->ops->teardown)
                ds->ops->teardown(ds);
unregister_notifier:
        dsa_switch_unregister_notifier(ds);
devlink_free:
        dsa_switch_devlink_free(ds);
        return err;
}

static void dsa_switch_teardown(struct dsa_switch *ds)
{
        if (!ds->setup)
                return;

        dsa_switch_devlink_unregister(ds);

        if (ds->user_mii_bus && ds->ops->phy_read) {
                mdiobus_unregister(ds->user_mii_bus);
                mdiobus_free(ds->user_mii_bus);
                ds->user_mii_bus = NULL;
        }

        dsa_switch_teardown_tag_protocol(ds);

        if (ds->ops->teardown)
                ds->ops->teardown(ds);

        dsa_switch_unregister_notifier(ds);

        dsa_switch_devlink_free(ds);

        ds->setup = false;
}

/* First tear down the non-shared, then the shared ports. This ensures that
 * all work items scheduled by our switchdev handlers for user ports have
 * completed before we destroy the refcounting kept on the shared ports.
 */
static void dsa_tree_teardown_ports(struct dsa_switch_tree *dst)
{
        struct dsa_port *dp;

        list_for_each_entry(dp, &dst->ports, list)
                if (dsa_port_is_user(dp) || dsa_port_is_unused(dp))
                        dsa_port_teardown(dp);

        dsa_flush_workqueue();

        list_for_each_entry(dp, &dst->ports, list)
                if (dsa_port_is_dsa(dp) || dsa_port_is_cpu(dp))
                        dsa_port_teardown(dp);
}

static void dsa_tree_teardown_switches(struct dsa_switch_tree *dst)
{
        struct dsa_port *dp;

        list_for_each_entry(dp, &dst->ports, list)
                dsa_switch_teardown(dp->ds);
}

/* Bring shared ports up first, then non-shared ports */
static int dsa_tree_setup_ports(struct dsa_switch_tree *dst)
{
        struct dsa_port *dp;
        int err = 0;

        list_for_each_entry(dp, &dst->ports, list) {
                if (dsa_port_is_dsa(dp) || dsa_port_is_cpu(dp)) {
                        err = dsa_port_setup(dp);
                        if (err)
                                goto teardown;
                }
        }

        list_for_each_entry(dp, &dst->ports, list) {
                if (dsa_port_is_user(dp) || dsa_port_is_unused(dp)) {
                        err = dsa_port_setup(dp);
                        if (err) {
                                err = dsa_port_setup_as_unused(dp);
                                if (err)
                                        goto teardown;
                        }
                }
        }

        return 0;

teardown:
        dsa_tree_teardown_ports(dst);

        return err;
}

static int dsa_tree_setup_switches(struct dsa_switch_tree *dst)
{
        struct dsa_port *dp;
        int err = 0;

        list_for_each_entry(dp, &dst->ports, list) {
                err = dsa_switch_setup(dp->ds);
                if (err) {
                        dsa_tree_teardown_switches(dst);
                        break;
                }
        }

        return err;
}

static int dsa_tree_setup_conduit(struct dsa_switch_tree *dst)
{
        struct dsa_port *cpu_dp;
        int err = 0;

        rtnl_lock();

        dsa_tree_for_each_cpu_port(cpu_dp, dst) {
                struct net_device *conduit = cpu_dp->conduit;
                bool admin_up = (conduit->flags & IFF_UP) &&
                                !qdisc_tx_is_noop(conduit);

                err = dsa_conduit_setup(conduit, cpu_dp);
                if (err)
                        break;

                /* Replay conduit state event */
                dsa_tree_conduit_admin_state_change(dst, conduit, admin_up);
                dsa_tree_conduit_oper_state_change(dst, conduit,
                                                   netif_oper_up(conduit));
        }

        rtnl_unlock();

        return err;
}

static void dsa_tree_teardown_conduit(struct dsa_switch_tree *dst)
{
        struct dsa_port *cpu_dp;

        rtnl_lock();

        dsa_tree_for_each_cpu_port(cpu_dp, dst) {
                struct net_device *conduit = cpu_dp->conduit;

                /* Synthesizing an "admin down" state is sufficient for
                 * the switches to get a notification if the conduit is
                 * currently up and running.
                 */
                dsa_tree_conduit_admin_state_change(dst, conduit, false);

                dsa_conduit_teardown(conduit);
        }

        rtnl_unlock();
}

static int dsa_tree_setup_lags(struct dsa_switch_tree *dst)
{
        unsigned int len = 0;
        struct dsa_port *dp;

        list_for_each_entry(dp, &dst->ports, list) {
                if (dp->ds->num_lag_ids > len)
                        len = dp->ds->num_lag_ids;
        }

        if (!len)
                return 0;

        dst->lags = kzalloc_objs(*dst->lags, len);
        if (!dst->lags)
                return -ENOMEM;

        dst->lags_len = len;
        return 0;
}

static void dsa_tree_teardown_lags(struct dsa_switch_tree *dst)
{
        kfree(dst->lags);
}

static void dsa_tree_teardown_routing_table(struct dsa_switch_tree *dst)
{
        struct dsa_link *dl, *next;

        list_for_each_entry_safe(dl, next, &dst->rtable, list) {
                list_del(&dl->list);
                kfree(dl);
        }
}

static int dsa_tree_setup(struct dsa_switch_tree *dst)
{
        bool complete;
        int err;

        if (dst->setup) {
                pr_err("DSA: tree %d already setup! Disjoint trees?\n",
                       dst->index);
                return -EEXIST;
        }

        complete = dsa_tree_setup_routing_table(dst);
        if (!complete)
                return 0;

        err = dsa_tree_setup_cpu_ports(dst);
        if (err)
                goto teardown_rtable;

        err = dsa_tree_setup_switches(dst);
        if (err)
                goto teardown_cpu_ports;

        err = dsa_tree_setup_ports(dst);
        if (err)
                goto teardown_switches;

        err = dsa_tree_setup_conduit(dst);
        if (err)
                goto teardown_ports;

        err = dsa_tree_setup_lags(dst);
        if (err)
                goto teardown_conduit;

        dst->setup = true;

        pr_info("DSA: tree %d setup\n", dst->index);

        return 0;

teardown_conduit:
        dsa_tree_teardown_conduit(dst);
teardown_ports:
        dsa_tree_teardown_ports(dst);
teardown_switches:
        dsa_tree_teardown_switches(dst);
teardown_cpu_ports:
        dsa_tree_teardown_cpu_ports(dst);
teardown_rtable:
        dsa_tree_teardown_routing_table(dst);

        return err;
}

static void dsa_tree_teardown(struct dsa_switch_tree *dst)
{
        if (!dst->setup)
                return;

        dsa_tree_teardown_lags(dst);

        dsa_tree_teardown_conduit(dst);

        dsa_tree_teardown_ports(dst);

        dsa_tree_teardown_switches(dst);

        dsa_tree_teardown_cpu_ports(dst);

        dsa_tree_teardown_routing_table(dst);

        pr_info("DSA: tree %d torn down\n", dst->index);

        dst->setup = false;
}

static int dsa_tree_bind_tag_proto(struct dsa_switch_tree *dst,
                                   const struct dsa_device_ops *tag_ops)
{
        const struct dsa_device_ops *old_tag_ops = dst->tag_ops;
        struct dsa_notifier_tag_proto_info info;
        int err;

        dst->tag_ops = tag_ops;

        /* Notify the switches from this tree about the connection
         * to the new tagger
         */
        info.tag_ops = tag_ops;
        err = dsa_tree_notify(dst, DSA_NOTIFIER_TAG_PROTO_CONNECT, &info);
        if (err && err != -EOPNOTSUPP)
                goto out_disconnect;

        /* Notify the old tagger about the disconnection from this tree */
        info.tag_ops = old_tag_ops;
        dsa_tree_notify(dst, DSA_NOTIFIER_TAG_PROTO_DISCONNECT, &info);

        return 0;

out_disconnect:
        info.tag_ops = tag_ops;
        dsa_tree_notify(dst, DSA_NOTIFIER_TAG_PROTO_DISCONNECT, &info);
        dst->tag_ops = old_tag_ops;

        return err;
}

/* Since the dsa/tagging sysfs device attribute is per conduit, the assumption
 * is that all DSA switches within a tree share the same tagger, otherwise
 * they would have formed disjoint trees (different "dsa,member" values).
 */
int dsa_tree_change_tag_proto(struct dsa_switch_tree *dst,
                              const struct dsa_device_ops *tag_ops,
                              const struct dsa_device_ops *old_tag_ops)
{
        struct dsa_notifier_tag_proto_info info;
        struct dsa_port *dp;
        int err = -EBUSY;

        if (!rtnl_trylock())
                return restart_syscall();

        /* At the moment we don't allow changing the tag protocol under
         * traffic. The rtnl_mutex also happens to serialize concurrent
         * attempts to change the tagging protocol. If we ever lift the IFF_UP
         * restriction, there needs to be another mutex which serializes this.
         */
        dsa_tree_for_each_user_port(dp, dst) {
                if (dsa_port_to_conduit(dp)->flags & IFF_UP)
                        goto out_unlock;

                if (dp->user->flags & IFF_UP)
                        goto out_unlock;
        }

        /* Notify the tag protocol change */
        info.tag_ops = tag_ops;
        err = dsa_tree_notify(dst, DSA_NOTIFIER_TAG_PROTO, &info);
        if (err)
                goto out_unwind_tagger;

        err = dsa_tree_bind_tag_proto(dst, tag_ops);
        if (err)
                goto out_unwind_tagger;

        rtnl_unlock();

        return 0;

out_unwind_tagger:
        info.tag_ops = old_tag_ops;
        dsa_tree_notify(dst, DSA_NOTIFIER_TAG_PROTO, &info);
out_unlock:
        rtnl_unlock();
        return err;
}

static void dsa_tree_conduit_state_change(struct dsa_switch_tree *dst,
                                          struct net_device *conduit)
{
        struct dsa_notifier_conduit_state_info info;
        struct dsa_port *cpu_dp = conduit->dsa_ptr;

        info.conduit = conduit;
        info.operational = dsa_port_conduit_is_operational(cpu_dp);

        dsa_tree_notify(dst, DSA_NOTIFIER_CONDUIT_STATE_CHANGE, &info);
}

void dsa_tree_conduit_admin_state_change(struct dsa_switch_tree *dst,
                                         struct net_device *conduit,
                                         bool up)
{
        struct dsa_port *cpu_dp = conduit->dsa_ptr;
        bool notify = false;

        /* Don't keep track of admin state on LAG DSA conduits,
         * but rather just of physical DSA conduits
         */
        if (netif_is_lag_master(conduit))
                return;

        if ((dsa_port_conduit_is_operational(cpu_dp)) !=
            (up && cpu_dp->conduit_oper_up))
                notify = true;

        cpu_dp->conduit_admin_up = up;

        if (notify)
                dsa_tree_conduit_state_change(dst, conduit);
}

void dsa_tree_conduit_oper_state_change(struct dsa_switch_tree *dst,
                                        struct net_device *conduit,
                                        bool up)
{
        struct dsa_port *cpu_dp = conduit->dsa_ptr;
        bool notify = false;

        /* Don't keep track of oper state on LAG DSA conduits,
         * but rather just of physical DSA conduits
         */
        if (netif_is_lag_master(conduit))
                return;

        if ((dsa_port_conduit_is_operational(cpu_dp)) !=
            (cpu_dp->conduit_admin_up && up))
                notify = true;

        cpu_dp->conduit_oper_up = up;

        if (notify)
                dsa_tree_conduit_state_change(dst, conduit);
}

static struct dsa_port *dsa_port_touch(struct dsa_switch *ds, int index)
{
        struct dsa_switch_tree *dst = ds->dst;
        struct dsa_port *dp;

        dsa_switch_for_each_port(dp, ds)
                if (dp->index == index)
                        return dp;

        dp = kzalloc_obj(*dp);
        if (!dp)
                return NULL;

        dp->ds = ds;
        dp->index = index;

        mutex_init(&dp->addr_lists_lock);
        mutex_init(&dp->vlans_lock);
        INIT_LIST_HEAD(&dp->fdbs);
        INIT_LIST_HEAD(&dp->mdbs);
        INIT_LIST_HEAD(&dp->vlans); /* also initializes &dp->user_vlans */
        INIT_LIST_HEAD(&dp->list);
        list_add_tail(&dp->list, &dst->ports);

        return dp;
}

static int dsa_port_parse_user(struct dsa_port *dp, const char *name)
{
        dp->type = DSA_PORT_TYPE_USER;
        dp->name = name;

        return 0;
}

static int dsa_port_parse_dsa(struct dsa_port *dp)
{
        dp->type = DSA_PORT_TYPE_DSA;

        return 0;
}

static enum dsa_tag_protocol dsa_get_tag_protocol(struct dsa_port *dp,
                                                  struct net_device *conduit)
{
        enum dsa_tag_protocol tag_protocol = DSA_TAG_PROTO_NONE;
        struct dsa_switch *mds, *ds = dp->ds;
        unsigned int mdp_upstream;
        struct dsa_port *mdp;

        /* It is possible to stack DSA switches onto one another when that
         * happens the switch driver may want to know if its tagging protocol
         * is going to work in such a configuration.
         */
        if (dsa_user_dev_check(conduit)) {
                mdp = dsa_user_to_port(conduit);
                mds = mdp->ds;
                mdp_upstream = dsa_upstream_port(mds, mdp->index);
                tag_protocol = mds->ops->get_tag_protocol(mds, mdp_upstream,
                                                          DSA_TAG_PROTO_NONE);
        }

        /* If the conduit device is not itself a DSA user in a disjoint DSA
         * tree, then return immediately.
         */
        return ds->ops->get_tag_protocol(ds, dp->index, tag_protocol);
}

static int dsa_port_parse_cpu(struct dsa_port *dp, struct net_device *conduit,
                              const char *user_protocol)
{
        const struct dsa_device_ops *tag_ops = NULL;
        struct dsa_switch *ds = dp->ds;
        struct dsa_switch_tree *dst = ds->dst;
        enum dsa_tag_protocol default_proto;

        /* Find out which protocol the switch would prefer. */
        default_proto = dsa_get_tag_protocol(dp, conduit);
        if (dst->default_proto) {
                if (dst->default_proto != default_proto) {
                        dev_err(ds->dev,
                                "A DSA switch tree can have only one tagging protocol\n");
                        return -EINVAL;
                }
        } else {
                dst->default_proto = default_proto;
        }

        /* See if the user wants to override that preference. */
        if (user_protocol) {
                if (!ds->ops->change_tag_protocol) {
                        dev_err(ds->dev, "Tag protocol cannot be modified\n");
                        return -EINVAL;
                }

                tag_ops = dsa_tag_driver_get_by_name(user_protocol);
                if (IS_ERR(tag_ops)) {
                        dev_warn(ds->dev,
                                 "Failed to find a tagging driver for protocol %s, using default\n",
                                 user_protocol);
                        tag_ops = NULL;
                }
        }

        if (!tag_ops)
                tag_ops = dsa_tag_driver_get_by_id(default_proto);

        if (IS_ERR(tag_ops)) {
                if (PTR_ERR(tag_ops) == -ENOPROTOOPT)
                        return -EPROBE_DEFER;

                dev_warn(ds->dev, "No tagger for this switch\n");
                return PTR_ERR(tag_ops);
        }

        if (dst->tag_ops) {
                if (dst->tag_ops != tag_ops) {
                        dev_err(ds->dev,
                                "A DSA switch tree can have only one tagging protocol\n");

                        dsa_tag_driver_put(tag_ops);
                        return -EINVAL;
                }

                /* In the case of multiple CPU ports per switch, the tagging
                 * protocol is still reference-counted only per switch tree.
                 */
                dsa_tag_driver_put(tag_ops);
        } else {
                dst->tag_ops = tag_ops;
        }

        dp->conduit = conduit;
        dp->type = DSA_PORT_TYPE_CPU;
        dsa_port_set_tag_protocol(dp, dst->tag_ops);
        dp->dst = dst;

        /* At this point, the tree may be configured to use a different
         * tagger than the one chosen by the switch driver during
         * .setup, in the case when a user selects a custom protocol
         * through the DT.
         *
         * This is resolved by syncing the driver with the tree in
         * dsa_switch_setup_tag_protocol once .setup has run and the
         * driver is ready to accept calls to .change_tag_protocol. If
         * the driver does not support the custom protocol at that
         * point, the tree is wholly rejected, thereby ensuring that the
         * tree and driver are always in agreement on the protocol to
         * use.
         */
        return 0;
}

static int dsa_port_parse_of(struct dsa_port *dp, struct device_node *dn)
{
        struct device_node *ethernet = of_parse_phandle(dn, "ethernet", 0);
        const char *name = of_get_property(dn, "label", NULL);
        bool link = of_property_read_bool(dn, "link");

        dp->dn = dn;

        if (ethernet) {
                struct net_device *conduit;
                const char *user_protocol;
                int err;

                rtnl_lock();
                conduit = of_find_net_device_by_node(ethernet);
                of_node_put(ethernet);
                if (!conduit) {
                        rtnl_unlock();
                        return -EPROBE_DEFER;
                }

                netdev_hold(conduit, &dp->conduit_tracker, GFP_KERNEL);
                put_device(&conduit->dev);
                rtnl_unlock();

                user_protocol = of_get_property(dn, "dsa-tag-protocol", NULL);
                err = dsa_port_parse_cpu(dp, conduit, user_protocol);
                if (err)
                        netdev_put(conduit, &dp->conduit_tracker);
                return err;
        }

        if (link)
                return dsa_port_parse_dsa(dp);

        return dsa_port_parse_user(dp, name);
}

static int dsa_switch_parse_ports_of(struct dsa_switch *ds,
                                     struct device_node *dn)
{
        struct device_node *ports, *port;
        struct dsa_port *dp;
        int err = 0;
        u32 reg;

        ports = of_get_child_by_name(dn, "ports");
        if (!ports) {
                /* The second possibility is "ethernet-ports" */
                ports = of_get_child_by_name(dn, "ethernet-ports");
                if (!ports) {
                        dev_err(ds->dev, "no ports child node found\n");
                        return -EINVAL;
                }
        }

        for_each_available_child_of_node(ports, port) {
                err = of_property_read_u32(port, "reg", &reg);
                if (err) {
                        of_node_put(port);
                        goto out_put_node;
                }

                if (reg >= ds->num_ports) {
                        dev_err(ds->dev, "port %pOF index %u exceeds num_ports (%u)\n",
                                port, reg, ds->num_ports);
                        of_node_put(port);
                        err = -EINVAL;
                        goto out_put_node;
                }

                dp = dsa_to_port(ds, reg);

                err = dsa_port_parse_of(dp, port);
                if (err) {
                        of_node_put(port);
                        goto out_put_node;
                }
        }

out_put_node:
        of_node_put(ports);
        return err;
}

static int dsa_switch_parse_member_of(struct dsa_switch *ds,
                                      struct device_node *dn)
{
        u32 m[2] = { 0, 0 };
        int sz;

        /* Don't error out if this optional property isn't found */
        sz = of_property_read_variable_u32_array(dn, "dsa,member", m, 2, 2);
        if (sz < 0 && sz != -EINVAL)
                return sz;

        ds->index = m[1];

        ds->dst = dsa_tree_touch(m[0]);
        if (!ds->dst)
                return -ENOMEM;

        if (dsa_switch_find(ds->dst->index, ds->index)) {
                dev_err(ds->dev,
                        "A DSA switch with index %d already exists in tree %d\n",
                        ds->index, ds->dst->index);
                return -EEXIST;
        }

        if (ds->dst->last_switch < ds->index)
                ds->dst->last_switch = ds->index;

        return 0;
}

static int dsa_switch_touch_ports(struct dsa_switch *ds)
{
        struct dsa_port *dp;
        int port;

        for (port = 0; port < ds->num_ports; port++) {
                dp = dsa_port_touch(ds, port);
                if (!dp)
                        return -ENOMEM;
        }

        return 0;
}

static int dsa_switch_parse_of(struct dsa_switch *ds, struct device_node *dn)
{
        int err;

        err = dsa_switch_parse_member_of(ds, dn);
        if (err)
                return err;

        err = dsa_switch_touch_ports(ds);
        if (err)
                return err;

        return dsa_switch_parse_ports_of(ds, dn);
}

static int dev_is_class(struct device *dev, const void *class)
{
        if (dev->class != NULL && !strcmp(dev->class->name, class))
                return 1;

        return 0;
}

static struct device *dev_find_class(struct device *parent, char *class)
{
        if (dev_is_class(parent, class)) {
                get_device(parent);
                return parent;
        }

        return device_find_child(parent, class, dev_is_class);
}

static int dsa_port_parse(struct dsa_port *dp, const char *name,
                          struct device *dev)
{
        if (!strcmp(name, "cpu")) {
                struct net_device *conduit;
                struct device *d;
                int err;

                rtnl_lock();
                d = dev_find_class(dev, "net");
                if (!d) {
                        rtnl_unlock();
                        return -EPROBE_DEFER;
                }

                conduit = to_net_dev(d);
                netdev_hold(conduit, &dp->conduit_tracker, GFP_KERNEL);
                put_device(d);
                rtnl_unlock();

                err = dsa_port_parse_cpu(dp, conduit, NULL);
                if (err)
                        netdev_put(conduit, &dp->conduit_tracker);
                return err;
        }

        if (!strcmp(name, "dsa"))
                return dsa_port_parse_dsa(dp);

        return dsa_port_parse_user(dp, name);
}

static int dsa_switch_parse_ports(struct dsa_switch *ds,
                                  struct dsa_chip_data *cd)
{
        bool valid_name_found = false;
        struct dsa_port *dp;
        struct device *dev;
        const char *name;
        unsigned int i;
        int err;

        for (i = 0; i < DSA_MAX_PORTS; i++) {
                name = cd->port_names[i];
                dev = cd->netdev[i];
                dp = dsa_to_port(ds, i);

                if (!name)
                        continue;

                err = dsa_port_parse(dp, name, dev);
                if (err)
                        return err;

                valid_name_found = true;
        }

        if (!valid_name_found && i == DSA_MAX_PORTS)
                return -EINVAL;

        return 0;
}

static int dsa_switch_parse(struct dsa_switch *ds, struct dsa_chip_data *cd)
{
        int err;

        ds->cd = cd;

        /* We don't support interconnected switches nor multiple trees via
         * platform data, so this is the unique switch of the tree.
         */
        ds->index = 0;
        ds->dst = dsa_tree_touch(0);
        if (!ds->dst)
                return -ENOMEM;

        err = dsa_switch_touch_ports(ds);
        if (err)
                return err;

        return dsa_switch_parse_ports(ds, cd);
}

static void dsa_switch_release_ports(struct dsa_switch *ds)
{
        struct dsa_mac_addr *a, *tmp;
        struct dsa_port *dp, *next;
        struct dsa_vlan *v, *n;

        dsa_switch_for_each_port_safe(dp, next, ds) {
                if (dsa_port_is_cpu(dp) && dp->conduit)
                        netdev_put(dp->conduit, &dp->conduit_tracker);

                /* These are either entries that upper layers lost track of
                 * (probably due to bugs), or installed through interfaces
                 * where one does not necessarily have to remove them, like
                 * ndo_dflt_fdb_add().
                 */
                list_for_each_entry_safe(a, tmp, &dp->fdbs, list) {
                        dev_info(ds->dev,
                                 "Cleaning up unicast address %pM vid %u from port %d\n",
                                 a->addr, a->vid, dp->index);
                        list_del(&a->list);
                        kfree(a);
                }

                list_for_each_entry_safe(a, tmp, &dp->mdbs, list) {
                        dev_info(ds->dev,
                                 "Cleaning up multicast address %pM vid %u from port %d\n",
                                 a->addr, a->vid, dp->index);
                        list_del(&a->list);
                        kfree(a);
                }

                /* These are entries that upper layers have lost track of,
                 * probably due to bugs, but also due to dsa_port_do_vlan_del()
                 * having failed and the VLAN entry still lingering on.
                 */
                list_for_each_entry_safe(v, n, &dp->vlans, list) {
                        dev_info(ds->dev,
                                 "Cleaning up vid %u from port %d\n",
                                 v->vid, dp->index);
                        list_del(&v->list);
                        kfree(v);
                }

                list_del(&dp->list);
                kfree(dp);
        }
}

static int dsa_switch_probe(struct dsa_switch *ds)
{
        struct dsa_switch_tree *dst;
        struct dsa_chip_data *pdata;
        struct device_node *np;
        int err;

        if (!ds->dev)
                return -ENODEV;

        pdata = ds->dev->platform_data;
        np = ds->dev->of_node;

        if (!ds->num_ports)
                return -EINVAL;

        if (np) {
                err = dsa_switch_parse_of(ds, np);
                if (err)
                        dsa_switch_release_ports(ds);
        } else if (pdata) {
                err = dsa_switch_parse(ds, pdata);
                if (err)
                        dsa_switch_release_ports(ds);
        } else {
                err = -ENODEV;
        }

        if (err)
                return err;

        dst = ds->dst;
        dsa_tree_get(dst);
        err = dsa_tree_setup(dst);
        if (err) {
                dsa_switch_release_ports(ds);
                dsa_tree_put(dst);
        }

        return err;
}

int dsa_register_switch(struct dsa_switch *ds)
{
        int err;

        mutex_lock(&dsa2_mutex);
        err = dsa_switch_probe(ds);
        dsa_tree_put(ds->dst);
        mutex_unlock(&dsa2_mutex);

        return err;
}
EXPORT_SYMBOL_GPL(dsa_register_switch);

static void dsa_switch_remove(struct dsa_switch *ds)
{
        struct dsa_switch_tree *dst = ds->dst;

        dsa_tree_teardown(dst);
        dsa_switch_release_ports(ds);
        dsa_tree_put(dst);
}

void dsa_unregister_switch(struct dsa_switch *ds)
{
        mutex_lock(&dsa2_mutex);
        dsa_switch_remove(ds);
        mutex_unlock(&dsa2_mutex);
}
EXPORT_SYMBOL_GPL(dsa_unregister_switch);

/* If the DSA conduit chooses to unregister its net_device on .shutdown, DSA is
 * blocking that operation from completion, due to the dev_hold taken inside
 * netdev_upper_dev_link. Unlink the DSA user interfaces from being uppers of
 * the DSA conduit, so that the system can reboot successfully.
 */
void dsa_switch_shutdown(struct dsa_switch *ds)
{
        struct net_device *conduit, *user_dev;
        LIST_HEAD(close_list);
        struct dsa_port *dp;

        mutex_lock(&dsa2_mutex);

        if (!ds->setup)
                goto out;

        rtnl_lock();

        dsa_switch_for_each_cpu_port(dp, ds)
                list_add(&dp->conduit->close_list, &close_list);

        netif_close_many(&close_list, true);

        dsa_switch_for_each_user_port(dp, ds) {
                conduit = dsa_port_to_conduit(dp);
                user_dev = dp->user;

                netif_device_detach(user_dev);
                netdev_upper_dev_unlink(conduit, user_dev);
        }

        /* Disconnect from further netdevice notifiers on the conduit,
         * since netdev_uses_dsa() will now return false.
         */
        dsa_switch_for_each_cpu_port(dp, ds) {
                dp->conduit->dsa_ptr = NULL;
                netdev_put(dp->conduit, &dp->conduit_tracker);
        }

        rtnl_unlock();
out:
        mutex_unlock(&dsa2_mutex);
}
EXPORT_SYMBOL_GPL(dsa_switch_shutdown);

#ifdef CONFIG_PM_SLEEP
static bool dsa_port_is_initialized(const struct dsa_port *dp)
{
        return dp->type == DSA_PORT_TYPE_USER && dp->user;
}

int dsa_switch_suspend(struct dsa_switch *ds)
{
        struct dsa_port *dp;
        int ret = 0;

        /* Suspend user network devices */
        dsa_switch_for_each_port(dp, ds) {
                if (!dsa_port_is_initialized(dp))
                        continue;

                ret = dsa_user_suspend(dp->user);
                if (ret)
                        return ret;
        }

        if (ds->ops->suspend)
                ret = ds->ops->suspend(ds);

        return ret;
}
EXPORT_SYMBOL_GPL(dsa_switch_suspend);

int dsa_switch_resume(struct dsa_switch *ds)
{
        struct dsa_port *dp;
        int ret = 0;

        if (ds->ops->resume)
                ret = ds->ops->resume(ds);

        if (ret)
                return ret;

        /* Resume user network devices */
        dsa_switch_for_each_port(dp, ds) {
                if (!dsa_port_is_initialized(dp))
                        continue;

                ret = dsa_user_resume(dp->user);
                if (ret)
                        return ret;
        }

        return 0;
}
EXPORT_SYMBOL_GPL(dsa_switch_resume);
#endif

struct dsa_port *dsa_port_from_netdev(struct net_device *netdev)
{
        if (!netdev || !dsa_user_dev_check(netdev))
                return ERR_PTR(-ENODEV);

        return dsa_user_to_port(netdev);
}
EXPORT_SYMBOL_GPL(dsa_port_from_netdev);

bool dsa_db_equal(const struct dsa_db *a, const struct dsa_db *b)
{
        if (a->type != b->type)
                return false;

        switch (a->type) {
        case DSA_DB_PORT:
                return a->dp == b->dp;
        case DSA_DB_LAG:
                return a->lag.dev == b->lag.dev;
        case DSA_DB_BRIDGE:
                return a->bridge.num == b->bridge.num;
        default:
                WARN_ON(1);
                return false;
        }
}

bool dsa_fdb_present_in_other_db(struct dsa_switch *ds, int port,
                                 const unsigned char *addr, u16 vid,
                                 struct dsa_db db)
{
        struct dsa_port *dp = dsa_to_port(ds, port);
        struct dsa_mac_addr *a;

        lockdep_assert_held(&dp->addr_lists_lock);

        list_for_each_entry(a, &dp->fdbs, list) {
                if (!ether_addr_equal(a->addr, addr) || a->vid != vid)
                        continue;

                if (a->db.type == db.type && !dsa_db_equal(&a->db, &db))
                        return true;
        }

        return false;
}
EXPORT_SYMBOL_GPL(dsa_fdb_present_in_other_db);

bool dsa_mdb_present_in_other_db(struct dsa_switch *ds, int port,
                                 const struct switchdev_obj_port_mdb *mdb,
                                 struct dsa_db db)
{
        struct dsa_port *dp = dsa_to_port(ds, port);
        struct dsa_mac_addr *a;

        lockdep_assert_held(&dp->addr_lists_lock);

        list_for_each_entry(a, &dp->mdbs, list) {
                if (!ether_addr_equal(a->addr, mdb->addr) || a->vid != mdb->vid)
                        continue;

                if (a->db.type == db.type && !dsa_db_equal(&a->db, &db))
                        return true;
        }

        return false;
}
EXPORT_SYMBOL_GPL(dsa_mdb_present_in_other_db);

/* Helpers for switches without specific HSR offloads, but which can implement
 * NETIF_F_HW_HSR_DUP because their tagger uses dsa_xmit_port_mask()
 */
int dsa_port_simple_hsr_validate(struct dsa_switch *ds, int port,
                                 struct net_device *hsr,
                                 struct netlink_ext_ack *extack)
{
        enum hsr_port_type type;
        int err;

        err = hsr_get_port_type(hsr, dsa_to_port(ds, port)->user, &type);
        if (err)
                return err;

        if (type != HSR_PT_SLAVE_A && type != HSR_PT_SLAVE_B) {
                NL_SET_ERR_MSG_MOD(extack,
                                   "Only HSR slave ports can be offloaded");
                return -EOPNOTSUPP;
        }

        return 0;
}
EXPORT_SYMBOL_GPL(dsa_port_simple_hsr_validate);

int dsa_port_simple_hsr_join(struct dsa_switch *ds, int port,
                             struct net_device *hsr,
                             struct netlink_ext_ack *extack)
{
        struct dsa_port *dp = dsa_to_port(ds, port), *other_dp;
        int err;

        err = dsa_port_simple_hsr_validate(ds, port, hsr, extack);
        if (err)
                return err;

        dsa_hsr_foreach_port(other_dp, ds, hsr) {
                if (other_dp != dp) {
                        dp->user->features |= NETIF_F_HW_HSR_DUP;
                        other_dp->user->features |= NETIF_F_HW_HSR_DUP;
                        break;
                }
        }

        return 0;
}
EXPORT_SYMBOL_GPL(dsa_port_simple_hsr_join);

int dsa_port_simple_hsr_leave(struct dsa_switch *ds, int port,
                              struct net_device *hsr)
{
        struct dsa_port *dp = dsa_to_port(ds, port), *other_dp;

        dsa_hsr_foreach_port(other_dp, ds, hsr) {
                if (other_dp != dp) {
                        dp->user->features &= ~NETIF_F_HW_HSR_DUP;
                        other_dp->user->features &= ~NETIF_F_HW_HSR_DUP;
                        break;
                }
        }

        return 0;
}
EXPORT_SYMBOL_GPL(dsa_port_simple_hsr_leave);

static const struct dsa_stubs __dsa_stubs = {
        .conduit_hwtstamp_validate = __dsa_conduit_hwtstamp_validate,
};

static void dsa_register_stubs(void)
{
        dsa_stubs = &__dsa_stubs;
}

static void dsa_unregister_stubs(void)
{
        dsa_stubs = NULL;
}

static int __init dsa_init_module(void)
{
        int rc;

        dsa_owq = alloc_ordered_workqueue("dsa_ordered",
                                          WQ_MEM_RECLAIM);
        if (!dsa_owq)
                return -ENOMEM;

        rc = dsa_user_register_notifier();
        if (rc)
                goto register_notifier_fail;

        dev_add_pack(&dsa_pack_type);

        rc = rtnl_link_register(&dsa_link_ops);
        if (rc)
                goto netlink_register_fail;

        dsa_register_stubs();

        return 0;

netlink_register_fail:
        dsa_user_unregister_notifier();
        dev_remove_pack(&dsa_pack_type);
register_notifier_fail:
        destroy_workqueue(dsa_owq);

        return rc;
}
module_init(dsa_init_module);

static void __exit dsa_cleanup_module(void)
{
        dsa_unregister_stubs();

        rtnl_link_unregister(&dsa_link_ops);

        dsa_user_unregister_notifier();
        dev_remove_pack(&dsa_pack_type);
        destroy_workqueue(dsa_owq);
}
module_exit(dsa_cleanup_module);

MODULE_AUTHOR("Lennert Buytenhek <buytenh@wantstofly.org>");
MODULE_DESCRIPTION("Driver for Distributed Switch Architecture switch chips");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:dsa");
MODULE_IMPORT_NS("NETDEV_INTERNAL");