// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * net/dsa/dsa2.c - Hardware switch handling, binding version 2
 * 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/list.h>
#include <linux/netdevice.h>
#include <linux/slab.h>
#include <linux/rtnetlink.h>
#include <linux/of.h>
#include <linux/of_net.h>
#include <net/devlink.h>

#include "dsa_priv.h"

static DEFINE_MUTEX(dsa2_mutex);
LIST_HEAD(dsa_tree_list);

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

/**
 * dsa_tree_notify - Execute code for all switches in a DSA switch tree.
 * @dst: collection of struct dsa_switch devices to notify.
 * @e: event, must be of type DSA_NOTIFIER_*
 * @v: event-specific value.
 *
 * Given a struct dsa_switch_tree, this can be used to run a function once for
 * each member DSA switch. The other alternative of traversing the tree is only
 * through its ports list, which does not uniquely list the switches.
 */
int dsa_tree_notify(struct dsa_switch_tree *dst, unsigned long e, void *v)
{
        struct raw_notifier_head *nh = &dst->nh;
        int err;

        err = raw_notifier_call_chain(nh, e, v);

        return notifier_to_errno(err);
}

/**
 * dsa_broadcast - Notify all DSA trees in the system.
 * @e: event, must be of type DSA_NOTIFIER_*
 * @v: event-specific value.
 *
 * Can be used to notify the switching fabric of events such as cross-chip
 * bridging between disjoint trees (such as islands of tagger-compatible
 * switches bridged by an incompatible middle switch).
 *
 * WARNING: this function is not reliable during probe time, because probing
 * between trees is asynchronous and not all DSA trees might have probed.
 */
int dsa_broadcast(unsigned long e, void *v)
{
        struct dsa_switch_tree *dst;
        int err = 0;

        list_for_each_entry(dst, &dsa_tree_list, list) {
                err = dsa_tree_notify(dst, e, v);
                if (err)
                        break;
        }

        return err;
}

/**
 * dsa_lag_map() - Map LAG netdev to a linear LAG ID
 * @dst: Tree in which to record the mapping.
 * @lag: Netdev that is to be mapped to an ID.
 *
 * dsa_lag_id/dsa_lag_dev 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 net_device *lag)
{
        unsigned int id;

        if (dsa_lag_id(dst, lag) >= 0)
                /* Already mapped */
                return;

        for (id = 0; id < dst->lags_len; id++) {
                if (!dsa_lag_dev(dst, id)) {
                        dst->lags[id] = lag;
                        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: Netdev 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 net_device *lag)
{
        struct dsa_port *dp;
        unsigned int id;

        dsa_lag_foreach_port(dp, dst, lag)
                /* There are remaining users of this mapping */
                return;

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

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

        /* When preparing the offload for a port, it will have a valid
         * dp->bridge_dev pointer but a not yet valid dp->bridge_num.
         * However there might be other ports having the same dp->bridge_dev
         * and a valid dp->bridge_num, so just ignore this port.
         */
        list_for_each_entry(dst, &dsa_tree_list, list)
                list_for_each_entry(dp, &dst->ports, list)
                        if (dp->bridge_dev == bridge_dev &&
                            dp->bridge_num != -1)
                                return dp->bridge_num;

        return -1;
}

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

        if (bridge_num < 0) {
                /* First port that offloads TX forwarding for this bridge */
                bridge_num = find_first_zero_bit(&dsa_fwd_offloading_bridges,
                                                 DSA_MAX_NUM_OFFLOADING_BRIDGES);
                if (bridge_num >= max)
                        return -1;

                set_bit(bridge_num, &dsa_fwd_offloading_bridges);
        }

        return bridge_num;
}

void dsa_bridge_num_put(const struct net_device *bridge_dev, int bridge_num)
{
        /* Check if the bridge is still in use, otherwise it is time
         * to clean it up so we can reuse this bridge_num later.
         */
        if (dsa_bridge_num_find(bridge_dev) < 0)
                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(sizeof(*dst), GFP_KERNEL);
        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(sizeof(*dl), GFP_KERNEL);
        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;
}

/* 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;
}

/* 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 *cpu_dp, *dp;

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

                list_for_each_entry(dp, &dst->ports, list) {
                        /* Prefer a local CPU port */
                        if (dp->ds != cpu_dp->ds)
                                continue;

                        /* 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)
{
        struct devlink_port *dlp = &dp->devlink_port;
        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;

        INIT_LIST_HEAD(&dp->fdbs);
        INIT_LIST_HEAD(&dp->mdbs);

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

        switch (dp->type) {
        case DSA_PORT_TYPE_UNUSED:
                dsa_port_disable(dp);
                break;
        case DSA_PORT_TYPE_CPU:
                err = dsa_port_link_register_of(dp);
                if (err)
                        break;
                dsa_port_link_registered = true;

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

                break;
        case DSA_PORT_TYPE_DSA:
                err = dsa_port_link_register_of(dp);
                if (err)
                        break;
                dsa_port_link_registered = true;

                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_slave_create(dp);
                if (err)
                        break;

                devlink_port_type_eth_set(dlp, dp->slave);
                break;
        }

        if (err && dsa_port_enabled)
                dsa_port_disable(dp);
        if (err && dsa_port_link_registered)
                dsa_port_link_unregister_of(dp);
        if (err) {
                if (ds->ops->port_teardown)
                        ds->ops->port_teardown(ds, dp->index);
                return err;
        }

        dp->setup = true;

        return 0;
}

static int dsa_port_devlink_setup(struct dsa_port *dp)
{
        struct devlink_port *dlp = &dp->devlink_port;
        struct dsa_switch_tree *dst = dp->ds->dst;
        struct devlink_port_attrs attrs = {};
        struct devlink *dl = dp->ds->devlink;
        const unsigned char *id;
        unsigned char len;
        int err;

        id = (const unsigned char *)&dst->index;
        len = sizeof(dst->index);

        attrs.phys.port_number = dp->index;
        memcpy(attrs.switch_id.id, id, len);
        attrs.switch_id.id_len = len;
        memset(dlp, 0, sizeof(*dlp));

        switch (dp->type) {
        case DSA_PORT_TYPE_UNUSED:
                attrs.flavour = DEVLINK_PORT_FLAVOUR_UNUSED;
                break;
        case DSA_PORT_TYPE_CPU:
                attrs.flavour = DEVLINK_PORT_FLAVOUR_CPU;
                break;
        case DSA_PORT_TYPE_DSA:
                attrs.flavour = DEVLINK_PORT_FLAVOUR_DSA;
                break;
        case DSA_PORT_TYPE_USER:
                attrs.flavour = DEVLINK_PORT_FLAVOUR_PHYSICAL;
                break;
        }

        devlink_port_attrs_set(dlp, &attrs);
        err = devlink_port_register(dl, dlp, dp->index);

        if (!err)
                dp->devlink_port_setup = true;

        return err;
}

static void dsa_port_teardown(struct dsa_port *dp)
{
        struct devlink_port *dlp = &dp->devlink_port;
        struct dsa_switch *ds = dp->ds;
        struct dsa_mac_addr *a, *tmp;

        if (!dp->setup)
                return;

        if (ds->ops->port_teardown)
                ds->ops->port_teardown(ds, dp->index);

        devlink_port_type_clear(dlp);

        switch (dp->type) {
        case DSA_PORT_TYPE_UNUSED:
                break;
        case DSA_PORT_TYPE_CPU:
                dsa_port_disable(dp);
                dsa_port_link_unregister_of(dp);
                break;
        case DSA_PORT_TYPE_DSA:
                dsa_port_disable(dp);
                dsa_port_link_unregister_of(dp);
                break;
        case DSA_PORT_TYPE_USER:
                if (dp->slave) {
                        dsa_slave_destroy(dp->slave);
                        dp->slave = NULL;
                }
                break;
        }

        list_for_each_entry_safe(a, tmp, &dp->fdbs, list) {
                list_del(&a->list);
                kfree(a);
        }

        list_for_each_entry_safe(a, tmp, &dp->mdbs, list) {
                list_del(&a->list);
                kfree(a);
        }

        dp->setup = false;
}

static void dsa_port_devlink_teardown(struct dsa_port *dp)
{
        struct devlink_port *dlp = &dp->devlink_port;

        if (dp->devlink_port_setup)
                devlink_port_unregister(dlp);
        dp->devlink_port_setup = false;
}

/* Destroy the current devlink port, and create a new one which has the UNUSED
 * flavour. At this point, any call to ds->ops->port_setup has been already
 * balanced out by a call to ds->ops->port_teardown, so we know that any
 * devlink port regions the driver had are now unregistered. We then call its
 * ds->ops->port_setup again, in order for the driver to re-create them on the
 * new devlink port.
 */
static int dsa_port_reinit_as_unused(struct dsa_port *dp)
{
        struct dsa_switch *ds = dp->ds;
        int err;

        dsa_port_devlink_teardown(dp);
        dp->type = DSA_PORT_TYPE_UNUSED;
        err = dsa_port_devlink_setup(dp);
        if (err)
                return err;

        if (ds->ops->port_setup) {
                /* On error, leave the devlink port registered,
                 * dsa_switch_teardown will clean it up later.
                 */
                err = ds->ops->port_setup(ds, dp->index);
                if (err)
                        return err;
        }

        return 0;
}

static int dsa_devlink_info_get(struct devlink *dl,
                                struct devlink_info_req *req,
                                struct netlink_ext_ack *extack)
{
        struct dsa_switch *ds = dsa_devlink_to_ds(dl);

        if (ds->ops->devlink_info_get)
                return ds->ops->devlink_info_get(ds, req, extack);

        return -EOPNOTSUPP;
}

static int dsa_devlink_sb_pool_get(struct devlink *dl,
                                   unsigned int sb_index, u16 pool_index,
                                   struct devlink_sb_pool_info *pool_info)
{
        struct dsa_switch *ds = dsa_devlink_to_ds(dl);

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

        return ds->ops->devlink_sb_pool_get(ds, sb_index, pool_index,
                                            pool_info);
}

static int dsa_devlink_sb_pool_set(struct devlink *dl, unsigned int sb_index,
                                   u16 pool_index, u32 size,
                                   enum devlink_sb_threshold_type threshold_type,
                                   struct netlink_ext_ack *extack)
{
        struct dsa_switch *ds = dsa_devlink_to_ds(dl);

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

        return ds->ops->devlink_sb_pool_set(ds, sb_index, pool_index, size,
                                            threshold_type, extack);
}

static int dsa_devlink_sb_port_pool_get(struct devlink_port *dlp,
                                        unsigned int sb_index, u16 pool_index,
                                        u32 *p_threshold)
{
        struct dsa_switch *ds = dsa_devlink_port_to_ds(dlp);
        int port = dsa_devlink_port_to_port(dlp);

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

        return ds->ops->devlink_sb_port_pool_get(ds, port, sb_index,
                                                 pool_index, p_threshold);
}

static int dsa_devlink_sb_port_pool_set(struct devlink_port *dlp,
                                        unsigned int sb_index, u16 pool_index,
                                        u32 threshold,
                                        struct netlink_ext_ack *extack)
{
        struct dsa_switch *ds = dsa_devlink_port_to_ds(dlp);
        int port = dsa_devlink_port_to_port(dlp);

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

        return ds->ops->devlink_sb_port_pool_set(ds, port, sb_index,
                                                 pool_index, threshold, extack);
}

static int
dsa_devlink_sb_tc_pool_bind_get(struct devlink_port *dlp,
                                unsigned int sb_index, u16 tc_index,
                                enum devlink_sb_pool_type pool_type,
                                u16 *p_pool_index, u32 *p_threshold)
{
        struct dsa_switch *ds = dsa_devlink_port_to_ds(dlp);
        int port = dsa_devlink_port_to_port(dlp);

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

        return ds->ops->devlink_sb_tc_pool_bind_get(ds, port, sb_index,
                                                    tc_index, pool_type,
                                                    p_pool_index, p_threshold);
}

static int
dsa_devlink_sb_tc_pool_bind_set(struct devlink_port *dlp,
                                unsigned int sb_index, u16 tc_index,
                                enum devlink_sb_pool_type pool_type,
                                u16 pool_index, u32 threshold,
                                struct netlink_ext_ack *extack)
{
        struct dsa_switch *ds = dsa_devlink_port_to_ds(dlp);
        int port = dsa_devlink_port_to_port(dlp);

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

        return ds->ops->devlink_sb_tc_pool_bind_set(ds, port, sb_index,
                                                    tc_index, pool_type,
                                                    pool_index, threshold,
                                                    extack);
}

static int dsa_devlink_sb_occ_snapshot(struct devlink *dl,
                                       unsigned int sb_index)
{
        struct dsa_switch *ds = dsa_devlink_to_ds(dl);

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

        return ds->ops->devlink_sb_occ_snapshot(ds, sb_index);
}

static int dsa_devlink_sb_occ_max_clear(struct devlink *dl,
                                        unsigned int sb_index)
{
        struct dsa_switch *ds = dsa_devlink_to_ds(dl);

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

        return ds->ops->devlink_sb_occ_max_clear(ds, sb_index);
}

static int dsa_devlink_sb_occ_port_pool_get(struct devlink_port *dlp,
                                            unsigned int sb_index,
                                            u16 pool_index, u32 *p_cur,
                                            u32 *p_max)
{
        struct dsa_switch *ds = dsa_devlink_port_to_ds(dlp);
        int port = dsa_devlink_port_to_port(dlp);

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

        return ds->ops->devlink_sb_occ_port_pool_get(ds, port, sb_index,
                                                     pool_index, p_cur, p_max);
}

static int
dsa_devlink_sb_occ_tc_port_bind_get(struct devlink_port *dlp,
                                    unsigned int sb_index, u16 tc_index,
                                    enum devlink_sb_pool_type pool_type,
                                    u32 *p_cur, u32 *p_max)
{
        struct dsa_switch *ds = dsa_devlink_port_to_ds(dlp);
        int port = dsa_devlink_port_to_port(dlp);

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

        return ds->ops->devlink_sb_occ_tc_port_bind_get(ds, port,
                                                        sb_index, tc_index,
                                                        pool_type, p_cur,
                                                        p_max);
}

static const struct devlink_ops dsa_devlink_ops = {
        .info_get                       = dsa_devlink_info_get,
        .sb_pool_get                    = dsa_devlink_sb_pool_get,
        .sb_pool_set                    = dsa_devlink_sb_pool_set,
        .sb_port_pool_get               = dsa_devlink_sb_port_pool_get,
        .sb_port_pool_set               = dsa_devlink_sb_port_pool_set,
        .sb_tc_pool_bind_get            = dsa_devlink_sb_tc_pool_bind_get,
        .sb_tc_pool_bind_set            = dsa_devlink_sb_tc_pool_bind_set,
        .sb_occ_snapshot                = dsa_devlink_sb_occ_snapshot,
        .sb_occ_max_clear               = dsa_devlink_sb_occ_max_clear,
        .sb_occ_port_pool_get           = dsa_devlink_sb_occ_port_pool_get,
        .sb_occ_tc_port_bind_get        = dsa_devlink_sb_occ_tc_port_bind_get,
};

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 port, err;

        if (tag_ops->proto == dst->default_proto)
                return 0;

        for (port = 0; port < ds->num_ports; port++) {
                if (!dsa_is_cpu_port(ds, port))
                        continue;

                rtnl_lock();
                err = ds->ops->change_tag_protocol(ds, port, 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;
                }
        }

        return 0;
}

static int dsa_switch_setup(struct dsa_switch *ds)
{
        struct dsa_devlink_priv *dl_priv;
        struct dsa_port *dp;
        int err;

        if (ds->setup)
                return 0;

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

        /* Add the switch to devlink before calling setup, so that setup can
         * add dpipe tables
         */
        ds->devlink =
                devlink_alloc(&dsa_devlink_ops, sizeof(*dl_priv), ds->dev);
        if (!ds->devlink)
                return -ENOMEM;
        dl_priv = devlink_priv(ds->devlink);
        dl_priv->ds = ds;

        err = devlink_register(ds->devlink);
        if (err)
                goto free_devlink;

        /* Setup devlink port instances now, so that the switch
         * setup() can register regions etc, against the ports
         */
        list_for_each_entry(dp, &ds->dst->ports, list) {
                if (dp->ds == ds) {
                        err = dsa_port_devlink_setup(dp);
                        if (err)
                                goto unregister_devlink_ports;
                }
        }

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

        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;

        devlink_params_publish(ds->devlink);

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

                dsa_slave_mii_bus_init(ds);

                err = mdiobus_register(ds->slave_mii_bus);
                if (err < 0)
                        goto free_slave_mii_bus;
        }

        ds->setup = true;

        return 0;

free_slave_mii_bus:
        if (ds->slave_mii_bus && ds->ops->phy_read)
                mdiobus_free(ds->slave_mii_bus);
teardown:
        if (ds->ops->teardown)
                ds->ops->teardown(ds);
unregister_notifier:
        dsa_switch_unregister_notifier(ds);
unregister_devlink_ports:
        list_for_each_entry(dp, &ds->dst->ports, list)
                if (dp->ds == ds)
                        dsa_port_devlink_teardown(dp);
        devlink_unregister(ds->devlink);
free_devlink:
        devlink_free(ds->devlink);
        ds->devlink = NULL;

        return err;
}

static void dsa_switch_teardown(struct dsa_switch *ds)
{
        struct dsa_port *dp;

        if (!ds->setup)
                return;

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

        dsa_switch_unregister_notifier(ds);

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

        if (ds->devlink) {
                list_for_each_entry(dp, &ds->dst->ports, list)
                        if (dp->ds == ds)
                                dsa_port_devlink_teardown(dp);
                devlink_unregister(ds->devlink);
                devlink_free(ds->devlink);
                ds->devlink = NULL;
        }

        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);
}

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

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

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

        return 0;

teardown:
        dsa_tree_teardown_ports(dst);

        dsa_tree_teardown_switches(dst);

        return err;
}

static int dsa_tree_setup_master(struct dsa_switch_tree *dst)
{
        struct dsa_port *dp;
        int err;

        list_for_each_entry(dp, &dst->ports, list) {
                if (dsa_port_is_cpu(dp)) {
                        err = dsa_master_setup(dp->master, dp);
                        if (err)
                                return err;
                }
        }

        return 0;
}

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

        list_for_each_entry(dp, &dst->ports, list)
                if (dsa_port_is_cpu(dp))
                        dsa_master_teardown(dp->master);
}

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 = kcalloc(len, sizeof(*dst->lags), GFP_KERNEL);
        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 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)
                return err;

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

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

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

        dst->setup = true;

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

        return 0;

teardown_master:
        dsa_tree_teardown_master(dst);
teardown_switches:
        dsa_tree_teardown_ports(dst);
        dsa_tree_teardown_switches(dst);
teardown_cpu_ports:
        dsa_tree_teardown_cpu_ports(dst);

        return err;
}

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

        if (!dst->setup)
                return;

        dsa_tree_teardown_lags(dst);

        dsa_tree_teardown_master(dst);

        dsa_tree_teardown_ports(dst);

        dsa_tree_teardown_switches(dst);

        dsa_tree_teardown_cpu_ports(dst);

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

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

        dst->setup = false;
}

/* Since the dsa/tagging sysfs device attribute is per master, 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,
                              struct net_device *master,
                              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.
         */
        if (master->flags & IFF_UP)
                goto out_unlock;

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

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

        info.tag_ops = tag_ops;
        err = dsa_tree_notify(dst, DSA_NOTIFIER_TAG_PROTO, &info);
        if (err)
                goto out_unwind_tagger;

        dst->tag_ops = tag_ops;

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

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

        dp = kzalloc(sizeof(*dp), GFP_KERNEL);
        if (!dp)
                return NULL;

        dp->ds = ds;
        dp->index = index;
        dp->bridge_num = -1;

        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)
{
        if (!name)
                name = "eth%d";

        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 *master)
{
        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_slave_dev_check(master)) {
                mdp = dsa_slave_to_port(master);
                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 master device is not itself a DSA slave 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 *master,
                              const char *user_protocol)
{
        struct dsa_switch *ds = dp->ds;
        struct dsa_switch_tree *dst = ds->dst;
        const struct dsa_device_ops *tag_ops;
        enum dsa_tag_protocol default_proto;

        /* Find out which protocol the switch would prefer. */
        default_proto = dsa_get_tag_protocol(dp, master);
        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_find_tagger_by_name(user_protocol);
        } else {
                tag_ops = dsa_tag_driver_get(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->master = master;
        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 *master;
                const char *user_protocol;

                master = of_find_net_device_by_node(ethernet);
                if (!master)
                        return -EPROBE_DEFER;

                user_protocol = of_get_property(dn, "dsa-tag-protocol", NULL);
                return dsa_port_parse_cpu(dp, master, user_protocol);
        }

        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 (%zu)\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 dsa_port_parse(struct dsa_port *dp, const char *name,
                          struct device *dev)
{
        if (!strcmp(name, "cpu")) {
                struct net_device *master;

                master = dsa_dev_to_net_device(dev);
                if (!master)
                        return -EPROBE_DEFER;

                dev_put(master);

                return dsa_port_parse_cpu(dp, master, NULL);
        }

        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_switch_tree *dst = ds->dst;
        struct dsa_port *dp, *next;

        list_for_each_entry_safe(dp, next, &dst->ports, list) {
                if (dp->ds != ds)
                        continue;
                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 master 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 slave interfaces from being uppers of
 * the DSA master, so that the system can reboot successfully.
 */
void dsa_switch_shutdown(struct dsa_switch *ds)
{
        struct net_device *master, *slave_dev;
        LIST_HEAD(unregister_list);
        struct dsa_port *dp;

        mutex_lock(&dsa2_mutex);
        rtnl_lock();

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

                if (!dsa_port_is_user(dp))
                        continue;

                master = dp->cpu_dp->master;
                slave_dev = dp->slave;

                netdev_upper_dev_unlink(master, slave_dev);
                /* Just unlinking ourselves as uppers of the master is not
                 * sufficient. When the master net device unregisters, that will
                 * also call dev_close, which we will catch as NETDEV_GOING_DOWN
                 * and trigger a dev_close on our own devices (dsa_slave_close).
                 * In turn, that will call dev_mc_unsync on the master's net
                 * device. If the master is also a DSA switch port, this will
                 * trigger dsa_slave_set_rx_mode which will call dev_mc_sync on
                 * its own master. Lockdep will complain about the fact that
                 * all cascaded masters have the same dsa_master_addr_list_lock_key,
                 * which it normally would not do if the cascaded masters would
                 * be in a proper upper/lower relationship, which we've just
                 * destroyed.
                 * To suppress the lockdep warnings, let's actually unregister
                 * the DSA slave interfaces too, to avoid the nonsensical
                 * multicast address list synchronization on shutdown.
                 */
                unregister_netdevice_queue(slave_dev, &unregister_list);
        }
        unregister_netdevice_many(&unregister_list);

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