// SPDX-License-Identifier: GPL-2.0
/*
 * Thunderbolt driver - bus logic (NHI independent)
 *
 * Copyright (c) 2014 Andreas Noever <andreas.noever@gmail.com>
 * Copyright (C) 2019, Intel Corporation
 */

#include <linux/slab.h>
#include <linux/errno.h>
#include <linux/delay.h>

#include "tb.h"
#include "tb_regs.h"
#include "tunnel.h"

/**
 * struct tb_cm - Simple Thunderbolt connection manager
 * @tunnel_list: List of active tunnels
 * @dp_resources: List of available DP resources for DP tunneling
 * @hotplug_active: tb_handle_hotplug will stop progressing plug
 *                  events and exit if this is not set (it needs to
 *                  acquire the lock one more time). Used to drain wq
 *                  after cfg has been paused.
 */
struct tb_cm {
        struct list_head tunnel_list;
        struct list_head dp_resources;
        bool hotplug_active;
};

struct tb_hotplug_event {
        struct work_struct work;
        struct tb *tb;
        u64 route;
        u8 port;
        bool unplug;
};

static void tb_handle_hotplug(struct work_struct *work);

static void tb_queue_hotplug(struct tb *tb, u64 route, u8 port, bool unplug)
{
        struct tb_hotplug_event *ev;

        ev = kmalloc(sizeof(*ev), GFP_KERNEL);
        if (!ev)
                return;

        ev->tb = tb;
        ev->route = route;
        ev->port = port;
        ev->unplug = unplug;
        INIT_WORK(&ev->work, tb_handle_hotplug);
        queue_work(tb->wq, &ev->work);
}

/* enumeration & hot plug handling */

static void tb_add_dp_resources(struct tb_switch *sw)
{
        struct tb_cm *tcm = tb_priv(sw->tb);
        struct tb_port *port;

        tb_switch_for_each_port(sw, port) {
                if (!tb_port_is_dpin(port))
                        continue;

                if (!tb_switch_query_dp_resource(sw, port))
                        continue;

                list_add_tail(&port->list, &tcm->dp_resources);
                tb_port_dbg(port, "DP IN resource available\n");
        }
}

static void tb_remove_dp_resources(struct tb_switch *sw)
{
        struct tb_cm *tcm = tb_priv(sw->tb);
        struct tb_port *port, *tmp;

        /* Clear children resources first */
        tb_switch_for_each_port(sw, port) {
                if (tb_port_has_remote(port))
                        tb_remove_dp_resources(port->remote->sw);
        }

        list_for_each_entry_safe(port, tmp, &tcm->dp_resources, list) {
                if (port->sw == sw) {
                        tb_port_dbg(port, "DP OUT resource unavailable\n");
                        list_del_init(&port->list);
                }
        }
}

static void tb_discover_tunnels(struct tb_switch *sw)
{
        struct tb *tb = sw->tb;
        struct tb_cm *tcm = tb_priv(tb);
        struct tb_port *port;

        tb_switch_for_each_port(sw, port) {
                struct tb_tunnel *tunnel = NULL;

                switch (port->config.type) {
                case TB_TYPE_DP_HDMI_IN:
                        tunnel = tb_tunnel_discover_dp(tb, port);
                        break;

                case TB_TYPE_PCIE_DOWN:
                        tunnel = tb_tunnel_discover_pci(tb, port);
                        break;

                case TB_TYPE_USB3_DOWN:
                        tunnel = tb_tunnel_discover_usb3(tb, port);
                        break;

                default:
                        break;
                }

                if (!tunnel)
                        continue;

                if (tb_tunnel_is_pci(tunnel)) {
                        struct tb_switch *parent = tunnel->dst_port->sw;

                        while (parent != tunnel->src_port->sw) {
                                parent->boot = true;
                                parent = tb_switch_parent(parent);
                        }
                }

                list_add_tail(&tunnel->list, &tcm->tunnel_list);
        }

        tb_switch_for_each_port(sw, port) {
                if (tb_port_has_remote(port))
                        tb_discover_tunnels(port->remote->sw);
        }
}

static void tb_scan_xdomain(struct tb_port *port)
{
        struct tb_switch *sw = port->sw;
        struct tb *tb = sw->tb;
        struct tb_xdomain *xd;
        u64 route;

        route = tb_downstream_route(port);
        xd = tb_xdomain_find_by_route(tb, route);
        if (xd) {
                tb_xdomain_put(xd);
                return;
        }

        xd = tb_xdomain_alloc(tb, &sw->dev, route, tb->root_switch->uuid,
                              NULL);
        if (xd) {
                tb_port_at(route, sw)->xdomain = xd;
                tb_xdomain_add(xd);
        }
}

static int tb_enable_tmu(struct tb_switch *sw)
{
        int ret;

        /* If it is already enabled in correct mode, don't touch it */
        if (tb_switch_tmu_is_enabled(sw))
                return 0;

        ret = tb_switch_tmu_disable(sw);
        if (ret)
                return ret;

        ret = tb_switch_tmu_post_time(sw);
        if (ret)
                return ret;

        return tb_switch_tmu_enable(sw);
}

/**
 * tb_find_unused_port() - return the first inactive port on @sw
 * @sw: Switch to find the port on
 * @type: Port type to look for
 */
static struct tb_port *tb_find_unused_port(struct tb_switch *sw,
                                           enum tb_port_type type)
{
        struct tb_port *port;

        tb_switch_for_each_port(sw, port) {
                if (tb_is_upstream_port(port))
                        continue;
                if (port->config.type != type)
                        continue;
                if (!port->cap_adap)
                        continue;
                if (tb_port_is_enabled(port))
                        continue;
                return port;
        }
        return NULL;
}

static struct tb_port *tb_find_usb3_down(struct tb_switch *sw,
                                        const struct tb_port *port)
{
        struct tb_port *down;

        down = usb4_switch_map_usb3_down(sw, port);
        if (down) {
                if (WARN_ON(!tb_port_is_usb3_down(down)))
                        goto out;
                if (WARN_ON(tb_usb3_port_is_enabled(down)))
                        goto out;

                return down;
        }

out:
        return tb_find_unused_port(sw, TB_TYPE_USB3_DOWN);
}

static int tb_tunnel_usb3(struct tb *tb, struct tb_switch *sw)
{
        struct tb_switch *parent = tb_switch_parent(sw);
        struct tb_port *up, *down, *port;
        struct tb_cm *tcm = tb_priv(tb);
        struct tb_tunnel *tunnel;

        up = tb_switch_find_port(sw, TB_TYPE_USB3_UP);
        if (!up)
                return 0;

        /*
         * Look up available down port. Since we are chaining it should
         * be found right above this switch.
         */
        port = tb_port_at(tb_route(sw), parent);
        down = tb_find_usb3_down(parent, port);
        if (!down)
                return 0;

        if (tb_route(parent)) {
                struct tb_port *parent_up;
                /*
                 * Check first that the parent switch has its upstream USB3
                 * port enabled. Otherwise the chain is not complete and
                 * there is no point setting up a new tunnel.
                 */
                parent_up = tb_switch_find_port(parent, TB_TYPE_USB3_UP);
                if (!parent_up || !tb_port_is_enabled(parent_up))
                        return 0;
        }

        tunnel = tb_tunnel_alloc_usb3(tb, up, down);
        if (!tunnel)
                return -ENOMEM;

        if (tb_tunnel_activate(tunnel)) {
                tb_port_info(up,
                             "USB3 tunnel activation failed, aborting\n");
                tb_tunnel_free(tunnel);
                return -EIO;
        }

        list_add_tail(&tunnel->list, &tcm->tunnel_list);
        return 0;
}

static int tb_create_usb3_tunnels(struct tb_switch *sw)
{
        struct tb_port *port;
        int ret;

        if (tb_route(sw)) {
                ret = tb_tunnel_usb3(sw->tb, sw);
                if (ret)
                        return ret;
        }

        tb_switch_for_each_port(sw, port) {
                if (!tb_port_has_remote(port))
                        continue;
                ret = tb_create_usb3_tunnels(port->remote->sw);
                if (ret)
                        return ret;
        }

        return 0;
}

static void tb_scan_port(struct tb_port *port);

/**
 * tb_scan_switch() - scan for and initialize downstream switches
 */
static void tb_scan_switch(struct tb_switch *sw)
{
        struct tb_port *port;

        tb_switch_for_each_port(sw, port)
                tb_scan_port(port);
}

/**
 * tb_scan_port() - check for and initialize switches below port
 */
static void tb_scan_port(struct tb_port *port)
{
        struct tb_cm *tcm = tb_priv(port->sw->tb);
        struct tb_port *upstream_port;
        struct tb_switch *sw;

        if (tb_is_upstream_port(port))
                return;

        if (tb_port_is_dpout(port) && tb_dp_port_hpd_is_active(port) == 1 &&
            !tb_dp_port_is_enabled(port)) {
                tb_port_dbg(port, "DP adapter HPD set, queuing hotplug\n");
                tb_queue_hotplug(port->sw->tb, tb_route(port->sw), port->port,
                                 false);
                return;
        }

        if (port->config.type != TB_TYPE_PORT)
                return;
        if (port->dual_link_port && port->link_nr)
                return; /*
                         * Downstream switch is reachable through two ports.
                         * Only scan on the primary port (link_nr == 0).
                         */
        if (tb_wait_for_port(port, false) <= 0)
                return;
        if (port->remote) {
                tb_port_dbg(port, "port already has a remote\n");
                return;
        }
        sw = tb_switch_alloc(port->sw->tb, &port->sw->dev,
                             tb_downstream_route(port));
        if (IS_ERR(sw)) {
                /*
                 * If there is an error accessing the connected switch
                 * it may be connected to another domain. Also we allow
                 * the other domain to be connected to a max depth switch.
                 */
                if (PTR_ERR(sw) == -EIO || PTR_ERR(sw) == -EADDRNOTAVAIL)
                        tb_scan_xdomain(port);
                return;
        }

        if (tb_switch_configure(sw)) {
                tb_switch_put(sw);
                return;
        }

        /*
         * If there was previously another domain connected remove it
         * first.
         */
        if (port->xdomain) {
                tb_xdomain_remove(port->xdomain);
                port->xdomain = NULL;
        }

        /*
         * Do not send uevents until we have discovered all existing
         * tunnels and know which switches were authorized already by
         * the boot firmware.
         */
        if (!tcm->hotplug_active)
                dev_set_uevent_suppress(&sw->dev, true);

        if (tb_switch_add(sw)) {
                tb_switch_put(sw);
                return;
        }

        /* Link the switches using both links if available */
        upstream_port = tb_upstream_port(sw);
        port->remote = upstream_port;
        upstream_port->remote = port;
        if (port->dual_link_port && upstream_port->dual_link_port) {
                port->dual_link_port->remote = upstream_port->dual_link_port;
                upstream_port->dual_link_port->remote = port->dual_link_port;
        }

        /* Enable lane bonding if supported */
        if (tb_switch_lane_bonding_enable(sw))
                tb_sw_warn(sw, "failed to enable lane bonding\n");

        if (tb_enable_tmu(sw))
                tb_sw_warn(sw, "failed to enable TMU\n");

        /*
         * Create USB 3.x tunnels only when the switch is plugged to the
         * domain. This is because we scan the domain also during discovery
         * and want to discover existing USB 3.x tunnels before we create
         * any new.
         */
        if (tcm->hotplug_active && tb_tunnel_usb3(sw->tb, sw))
                tb_sw_warn(sw, "USB3 tunnel creation failed\n");

        tb_scan_switch(sw);
}

static struct tb_tunnel *tb_find_tunnel(struct tb *tb, enum tb_tunnel_type type,
                                        struct tb_port *src_port,
                                        struct tb_port *dst_port)
{
        struct tb_cm *tcm = tb_priv(tb);
        struct tb_tunnel *tunnel;

        list_for_each_entry(tunnel, &tcm->tunnel_list, list) {
                if (tunnel->type == type &&
                    ((src_port && src_port == tunnel->src_port) ||
                     (dst_port && dst_port == tunnel->dst_port))) {
                        return tunnel;
                }
        }

        return NULL;
}

static void tb_deactivate_and_free_tunnel(struct tb_tunnel *tunnel)
{
        if (!tunnel)
                return;

        tb_tunnel_deactivate(tunnel);
        list_del(&tunnel->list);

        /*
         * In case of DP tunnel make sure the DP IN resource is deallocated
         * properly.
         */
        if (tb_tunnel_is_dp(tunnel)) {
                struct tb_port *in = tunnel->src_port;

                tb_switch_dealloc_dp_resource(in->sw, in);
        }

        tb_tunnel_free(tunnel);
}

/**
 * tb_free_invalid_tunnels() - destroy tunnels of devices that have gone away
 */
static void tb_free_invalid_tunnels(struct tb *tb)
{
        struct tb_cm *tcm = tb_priv(tb);
        struct tb_tunnel *tunnel;
        struct tb_tunnel *n;

        list_for_each_entry_safe(tunnel, n, &tcm->tunnel_list, list) {
                if (tb_tunnel_is_invalid(tunnel))
                        tb_deactivate_and_free_tunnel(tunnel);
        }
}

/**
 * tb_free_unplugged_children() - traverse hierarchy and free unplugged switches
 */
static void tb_free_unplugged_children(struct tb_switch *sw)
{
        struct tb_port *port;

        tb_switch_for_each_port(sw, port) {
                if (!tb_port_has_remote(port))
                        continue;

                if (port->remote->sw->is_unplugged) {
                        tb_remove_dp_resources(port->remote->sw);
                        tb_switch_lane_bonding_disable(port->remote->sw);
                        tb_switch_remove(port->remote->sw);
                        port->remote = NULL;
                        if (port->dual_link_port)
                                port->dual_link_port->remote = NULL;
                } else {
                        tb_free_unplugged_children(port->remote->sw);
                }
        }
}

static struct tb_port *tb_find_pcie_down(struct tb_switch *sw,
                                         const struct tb_port *port)
{
        struct tb_port *down = NULL;

        /*
         * To keep plugging devices consistently in the same PCIe
         * hierarchy, do mapping here for switch downstream PCIe ports.
         */
        if (tb_switch_is_usb4(sw)) {
                down = usb4_switch_map_pcie_down(sw, port);
        } else if (!tb_route(sw)) {
                int phy_port = tb_phy_port_from_link(port->port);
                int index;

                /*
                 * Hard-coded Thunderbolt port to PCIe down port mapping
                 * per controller.
                 */
                if (tb_switch_is_cactus_ridge(sw) ||
                    tb_switch_is_alpine_ridge(sw))
                        index = !phy_port ? 6 : 7;
                else if (tb_switch_is_falcon_ridge(sw))
                        index = !phy_port ? 6 : 8;
                else if (tb_switch_is_titan_ridge(sw))
                        index = !phy_port ? 8 : 9;
                else
                        goto out;

                /* Validate the hard-coding */
                if (WARN_ON(index > sw->config.max_port_number))
                        goto out;

                down = &sw->ports[index];
        }

        if (down) {
                if (WARN_ON(!tb_port_is_pcie_down(down)))
                        goto out;
                if (WARN_ON(tb_pci_port_is_enabled(down)))
                        goto out;

                return down;
        }

out:
        return tb_find_unused_port(sw, TB_TYPE_PCIE_DOWN);
}

static int tb_available_bw(struct tb_cm *tcm, struct tb_port *in,
                           struct tb_port *out)
{
        struct tb_switch *sw = out->sw;
        struct tb_tunnel *tunnel;
        int bw, available_bw = 40000;

        while (sw && sw != in->sw) {
                bw = sw->link_speed * sw->link_width * 1000; /* Mb/s */
                /* Leave 10% guard band */
                bw -= bw / 10;

                /*
                 * Check for any active DP tunnels that go through this
                 * switch and reduce their consumed bandwidth from
                 * available.
                 */
                list_for_each_entry(tunnel, &tcm->tunnel_list, list) {
                        int consumed_bw;

                        if (!tb_tunnel_switch_on_path(tunnel, sw))
                                continue;

                        consumed_bw = tb_tunnel_consumed_bandwidth(tunnel);
                        if (consumed_bw < 0)
                                return consumed_bw;

                        bw -= consumed_bw;
                }

                if (bw < available_bw)
                        available_bw = bw;

                sw = tb_switch_parent(sw);
        }

        return available_bw;
}

static void tb_tunnel_dp(struct tb *tb)
{
        struct tb_cm *tcm = tb_priv(tb);
        struct tb_port *port, *in, *out;
        struct tb_tunnel *tunnel;
        int available_bw;

        /*
         * Find pair of inactive DP IN and DP OUT adapters and then
         * establish a DP tunnel between them.
         */
        tb_dbg(tb, "looking for DP IN <-> DP OUT pairs:\n");

        in = NULL;
        out = NULL;
        list_for_each_entry(port, &tcm->dp_resources, list) {
                if (tb_port_is_enabled(port)) {
                        tb_port_dbg(port, "in use\n");
                        continue;
                }

                tb_port_dbg(port, "available\n");

                if (!in && tb_port_is_dpin(port))
                        in = port;
                else if (!out && tb_port_is_dpout(port))
                        out = port;
        }

        if (!in) {
                tb_dbg(tb, "no suitable DP IN adapter available, not tunneling\n");
                return;
        }
        if (!out) {
                tb_dbg(tb, "no suitable DP OUT adapter available, not tunneling\n");
                return;
        }

        if (tb_switch_alloc_dp_resource(in->sw, in)) {
                tb_port_dbg(in, "no resource available for DP IN, not tunneling\n");
                return;
        }

        /* Calculate available bandwidth between in and out */
        available_bw = tb_available_bw(tcm, in, out);
        if (available_bw < 0) {
                tb_warn(tb, "failed to determine available bandwidth\n");
                return;
        }

        tb_dbg(tb, "available bandwidth for new DP tunnel %u Mb/s\n",
               available_bw);

        tunnel = tb_tunnel_alloc_dp(tb, in, out, available_bw);
        if (!tunnel) {
                tb_port_dbg(out, "could not allocate DP tunnel\n");
                goto dealloc_dp;
        }

        if (tb_tunnel_activate(tunnel)) {
                tb_port_info(out, "DP tunnel activation failed, aborting\n");
                tb_tunnel_free(tunnel);
                goto dealloc_dp;
        }

        list_add_tail(&tunnel->list, &tcm->tunnel_list);
        return;

dealloc_dp:
        tb_switch_dealloc_dp_resource(in->sw, in);
}

static void tb_dp_resource_unavailable(struct tb *tb, struct tb_port *port)
{
        struct tb_port *in, *out;
        struct tb_tunnel *tunnel;

        if (tb_port_is_dpin(port)) {
                tb_port_dbg(port, "DP IN resource unavailable\n");
                in = port;
                out = NULL;
        } else {
                tb_port_dbg(port, "DP OUT resource unavailable\n");
                in = NULL;
                out = port;
        }

        tunnel = tb_find_tunnel(tb, TB_TUNNEL_DP, in, out);
        tb_deactivate_and_free_tunnel(tunnel);
        list_del_init(&port->list);

        /*
         * See if there is another DP OUT port that can be used for
         * to create another tunnel.
         */
        tb_tunnel_dp(tb);
}

static void tb_dp_resource_available(struct tb *tb, struct tb_port *port)
{
        struct tb_cm *tcm = tb_priv(tb);
        struct tb_port *p;

        if (tb_port_is_enabled(port))
                return;

        list_for_each_entry(p, &tcm->dp_resources, list) {
                if (p == port)
                        return;
        }

        tb_port_dbg(port, "DP %s resource available\n",
                    tb_port_is_dpin(port) ? "IN" : "OUT");
        list_add_tail(&port->list, &tcm->dp_resources);

        /* Look for suitable DP IN <-> DP OUT pairs now */
        tb_tunnel_dp(tb);
}

static int tb_tunnel_pci(struct tb *tb, struct tb_switch *sw)
{
        struct tb_port *up, *down, *port;
        struct tb_cm *tcm = tb_priv(tb);
        struct tb_switch *parent_sw;
        struct tb_tunnel *tunnel;

        up = tb_switch_find_port(sw, TB_TYPE_PCIE_UP);
        if (!up)
                return 0;

        /*
         * Look up available down port. Since we are chaining it should
         * be found right above this switch.
         */
        parent_sw = tb_to_switch(sw->dev.parent);
        port = tb_port_at(tb_route(sw), parent_sw);
        down = tb_find_pcie_down(parent_sw, port);
        if (!down)
                return 0;

        tunnel = tb_tunnel_alloc_pci(tb, up, down);
        if (!tunnel)
                return -ENOMEM;

        if (tb_tunnel_activate(tunnel)) {
                tb_port_info(up,
                             "PCIe tunnel activation failed, aborting\n");
                tb_tunnel_free(tunnel);
                return -EIO;
        }

        list_add_tail(&tunnel->list, &tcm->tunnel_list);
        return 0;
}

static int tb_approve_xdomain_paths(struct tb *tb, struct tb_xdomain *xd)
{
        struct tb_cm *tcm = tb_priv(tb);
        struct tb_port *nhi_port, *dst_port;
        struct tb_tunnel *tunnel;
        struct tb_switch *sw;

        sw = tb_to_switch(xd->dev.parent);
        dst_port = tb_port_at(xd->route, sw);
        nhi_port = tb_switch_find_port(tb->root_switch, TB_TYPE_NHI);

        mutex_lock(&tb->lock);
        tunnel = tb_tunnel_alloc_dma(tb, nhi_port, dst_port, xd->transmit_ring,
                                     xd->transmit_path, xd->receive_ring,
                                     xd->receive_path);
        if (!tunnel) {
                mutex_unlock(&tb->lock);
                return -ENOMEM;
        }

        if (tb_tunnel_activate(tunnel)) {
                tb_port_info(nhi_port,
                             "DMA tunnel activation failed, aborting\n");
                tb_tunnel_free(tunnel);
                mutex_unlock(&tb->lock);
                return -EIO;
        }

        list_add_tail(&tunnel->list, &tcm->tunnel_list);
        mutex_unlock(&tb->lock);
        return 0;
}

static void __tb_disconnect_xdomain_paths(struct tb *tb, struct tb_xdomain *xd)
{
        struct tb_port *dst_port;
        struct tb_tunnel *tunnel;
        struct tb_switch *sw;

        sw = tb_to_switch(xd->dev.parent);
        dst_port = tb_port_at(xd->route, sw);

        /*
         * It is possible that the tunnel was already teared down (in
         * case of cable disconnect) so it is fine if we cannot find it
         * here anymore.
         */
        tunnel = tb_find_tunnel(tb, TB_TUNNEL_DMA, NULL, dst_port);
        tb_deactivate_and_free_tunnel(tunnel);
}

static int tb_disconnect_xdomain_paths(struct tb *tb, struct tb_xdomain *xd)
{
        if (!xd->is_unplugged) {
                mutex_lock(&tb->lock);
                __tb_disconnect_xdomain_paths(tb, xd);
                mutex_unlock(&tb->lock);
        }
        return 0;
}

/* hotplug handling */

/**
 * tb_handle_hotplug() - handle hotplug event
 *
 * Executes on tb->wq.
 */
static void tb_handle_hotplug(struct work_struct *work)
{
        struct tb_hotplug_event *ev = container_of(work, typeof(*ev), work);
        struct tb *tb = ev->tb;
        struct tb_cm *tcm = tb_priv(tb);
        struct tb_switch *sw;
        struct tb_port *port;
        mutex_lock(&tb->lock);
        if (!tcm->hotplug_active)
                goto out; /* during init, suspend or shutdown */

        sw = tb_switch_find_by_route(tb, ev->route);
        if (!sw) {
                tb_warn(tb,
                        "hotplug event from non existent switch %llx:%x (unplug: %d)\n",
                        ev->route, ev->port, ev->unplug);
                goto out;
        }
        if (ev->port > sw->config.max_port_number) {
                tb_warn(tb,
                        "hotplug event from non existent port %llx:%x (unplug: %d)\n",
                        ev->route, ev->port, ev->unplug);
                goto put_sw;
        }
        port = &sw->ports[ev->port];
        if (tb_is_upstream_port(port)) {
                tb_dbg(tb, "hotplug event for upstream port %llx:%x (unplug: %d)\n",
                       ev->route, ev->port, ev->unplug);
                goto put_sw;
        }
        if (ev->unplug) {
                if (tb_port_has_remote(port)) {
                        tb_port_dbg(port, "switch unplugged\n");
                        tb_sw_set_unplugged(port->remote->sw);
                        tb_free_invalid_tunnels(tb);
                        tb_remove_dp_resources(port->remote->sw);
                        tb_switch_tmu_disable(port->remote->sw);
                        tb_switch_lane_bonding_disable(port->remote->sw);
                        tb_switch_remove(port->remote->sw);
                        port->remote = NULL;
                        if (port->dual_link_port)
                                port->dual_link_port->remote = NULL;
                        /* Maybe we can create another DP tunnel */
                        tb_tunnel_dp(tb);
                } else if (port->xdomain) {
                        struct tb_xdomain *xd = tb_xdomain_get(port->xdomain);

                        tb_port_dbg(port, "xdomain unplugged\n");
                        /*
                         * Service drivers are unbound during
                         * tb_xdomain_remove() so setting XDomain as
                         * unplugged here prevents deadlock if they call
                         * tb_xdomain_disable_paths(). We will tear down
                         * the path below.
                         */
                        xd->is_unplugged = true;
                        tb_xdomain_remove(xd);
                        port->xdomain = NULL;
                        __tb_disconnect_xdomain_paths(tb, xd);
                        tb_xdomain_put(xd);
                } else if (tb_port_is_dpout(port) || tb_port_is_dpin(port)) {
                        tb_dp_resource_unavailable(tb, port);
                } else {
                        tb_port_dbg(port,
                                   "got unplug event for disconnected port, ignoring\n");
                }
        } else if (port->remote) {
                tb_port_dbg(port, "got plug event for connected port, ignoring\n");
        } else {
                if (tb_port_is_null(port)) {
                        tb_port_dbg(port, "hotplug: scanning\n");
                        tb_scan_port(port);
                        if (!port->remote)
                                tb_port_dbg(port, "hotplug: no switch found\n");
                } else if (tb_port_is_dpout(port) || tb_port_is_dpin(port)) {
                        tb_dp_resource_available(tb, port);
                }
        }

put_sw:
        tb_switch_put(sw);
out:
        mutex_unlock(&tb->lock);
        kfree(ev);
}

/**
 * tb_schedule_hotplug_handler() - callback function for the control channel
 *
 * Delegates to tb_handle_hotplug.
 */
static void tb_handle_event(struct tb *tb, enum tb_cfg_pkg_type type,
                            const void *buf, size_t size)
{
        const struct cfg_event_pkg *pkg = buf;
        u64 route;

        if (type != TB_CFG_PKG_EVENT) {
                tb_warn(tb, "unexpected event %#x, ignoring\n", type);
                return;
        }

        route = tb_cfg_get_route(&pkg->header);

        if (tb_cfg_ack_plug(tb->ctl, route, pkg->port, pkg->unplug)) {
                tb_warn(tb, "could not ack plug event on %llx:%x\n", route,
                        pkg->port);
        }

        tb_queue_hotplug(tb, route, pkg->port, pkg->unplug);
}

static void tb_stop(struct tb *tb)
{
        struct tb_cm *tcm = tb_priv(tb);
        struct tb_tunnel *tunnel;
        struct tb_tunnel *n;

        /* tunnels are only present after everything has been initialized */
        list_for_each_entry_safe(tunnel, n, &tcm->tunnel_list, list) {
                /*
                 * DMA tunnels require the driver to be functional so we
                 * tear them down. Other protocol tunnels can be left
                 * intact.
                 */
                if (tb_tunnel_is_dma(tunnel))
                        tb_tunnel_deactivate(tunnel);
                tb_tunnel_free(tunnel);
        }
        tb_switch_remove(tb->root_switch);
        tcm->hotplug_active = false; /* signal tb_handle_hotplug to quit */
}

static int tb_scan_finalize_switch(struct device *dev, void *data)
{
        if (tb_is_switch(dev)) {
                struct tb_switch *sw = tb_to_switch(dev);

                /*
                 * If we found that the switch was already setup by the
                 * boot firmware, mark it as authorized now before we
                 * send uevent to userspace.
                 */
                if (sw->boot)
                        sw->authorized = 1;

                dev_set_uevent_suppress(dev, false);
                kobject_uevent(&dev->kobj, KOBJ_ADD);
                device_for_each_child(dev, NULL, tb_scan_finalize_switch);
        }

        return 0;
}

static int tb_start(struct tb *tb)
{
        struct tb_cm *tcm = tb_priv(tb);
        int ret;

        tb->root_switch = tb_switch_alloc(tb, &tb->dev, 0);
        if (IS_ERR(tb->root_switch))
                return PTR_ERR(tb->root_switch);

        /*
         * ICM firmware upgrade needs running firmware and in native
         * mode that is not available so disable firmware upgrade of the
         * root switch.
         */
        tb->root_switch->no_nvm_upgrade = true;

        ret = tb_switch_configure(tb->root_switch);
        if (ret) {
                tb_switch_put(tb->root_switch);
                return ret;
        }

        /* Announce the switch to the world */
        ret = tb_switch_add(tb->root_switch);
        if (ret) {
                tb_switch_put(tb->root_switch);
                return ret;
        }

        /* Enable TMU if it is off */
        tb_switch_tmu_enable(tb->root_switch);
        /* Full scan to discover devices added before the driver was loaded. */
        tb_scan_switch(tb->root_switch);
        /* Find out tunnels created by the boot firmware */
        tb_discover_tunnels(tb->root_switch);
        /*
         * If the boot firmware did not create USB 3.x tunnels create them
         * now for the whole topology.
         */
        tb_create_usb3_tunnels(tb->root_switch);
        /* Add DP IN resources for the root switch */
        tb_add_dp_resources(tb->root_switch);
        /* Make the discovered switches available to the userspace */
        device_for_each_child(&tb->root_switch->dev, NULL,
                              tb_scan_finalize_switch);

        /* Allow tb_handle_hotplug to progress events */
        tcm->hotplug_active = true;

        return 0;
}

static int tb_suspend_noirq(struct tb *tb)
{
        struct tb_cm *tcm = tb_priv(tb);

        tb_dbg(tb, "suspending...\n");
        tb_switch_suspend(tb->root_switch);
        tcm->hotplug_active = false; /* signal tb_handle_hotplug to quit */
        tb_dbg(tb, "suspend finished\n");

        return 0;
}

static void tb_restore_children(struct tb_switch *sw)
{
        struct tb_port *port;

        if (tb_enable_tmu(sw))
                tb_sw_warn(sw, "failed to restore TMU configuration\n");

        tb_switch_for_each_port(sw, port) {
                if (!tb_port_has_remote(port))
                        continue;

                if (tb_switch_lane_bonding_enable(port->remote->sw))
                        dev_warn(&sw->dev, "failed to restore lane bonding\n");

                tb_restore_children(port->remote->sw);
        }
}

static int tb_resume_noirq(struct tb *tb)
{
        struct tb_cm *tcm = tb_priv(tb);
        struct tb_tunnel *tunnel, *n;

        tb_dbg(tb, "resuming...\n");

        /* remove any pci devices the firmware might have setup */
        tb_switch_reset(tb, 0);

        tb_switch_resume(tb->root_switch);
        tb_free_invalid_tunnels(tb);
        tb_free_unplugged_children(tb->root_switch);
        tb_restore_children(tb->root_switch);
        list_for_each_entry_safe(tunnel, n, &tcm->tunnel_list, list)
                tb_tunnel_restart(tunnel);
        if (!list_empty(&tcm->tunnel_list)) {
                /*
                 * the pcie links need some time to get going.
                 * 100ms works for me...
                 */
                tb_dbg(tb, "tunnels restarted, sleeping for 100ms\n");
                msleep(100);
        }
         /* Allow tb_handle_hotplug to progress events */
        tcm->hotplug_active = true;
        tb_dbg(tb, "resume finished\n");

        return 0;
}

static int tb_free_unplugged_xdomains(struct tb_switch *sw)
{
        struct tb_port *port;
        int ret = 0;

        tb_switch_for_each_port(sw, port) {
                if (tb_is_upstream_port(port))
                        continue;
                if (port->xdomain && port->xdomain->is_unplugged) {
                        tb_xdomain_remove(port->xdomain);
                        port->xdomain = NULL;
                        ret++;
                } else if (port->remote) {
                        ret += tb_free_unplugged_xdomains(port->remote->sw);
                }
        }

        return ret;
}

static void tb_complete(struct tb *tb)
{
        /*
         * Release any unplugged XDomains and if there is a case where
         * another domain is swapped in place of unplugged XDomain we
         * need to run another rescan.
         */
        mutex_lock(&tb->lock);
        if (tb_free_unplugged_xdomains(tb->root_switch))
                tb_scan_switch(tb->root_switch);
        mutex_unlock(&tb->lock);
}

static const struct tb_cm_ops tb_cm_ops = {
        .start = tb_start,
        .stop = tb_stop,
        .suspend_noirq = tb_suspend_noirq,
        .resume_noirq = tb_resume_noirq,
        .complete = tb_complete,
        .handle_event = tb_handle_event,
        .approve_switch = tb_tunnel_pci,
        .approve_xdomain_paths = tb_approve_xdomain_paths,
        .disconnect_xdomain_paths = tb_disconnect_xdomain_paths,
};

struct tb *tb_probe(struct tb_nhi *nhi)
{
        struct tb_cm *tcm;
        struct tb *tb;

        tb = tb_domain_alloc(nhi, sizeof(*tcm));
        if (!tb)
                return NULL;

        tb->security_level = TB_SECURITY_USER;
        tb->cm_ops = &tb_cm_ops;

        tcm = tb_priv(tb);
        INIT_LIST_HEAD(&tcm->tunnel_list);
        INIT_LIST_HEAD(&tcm->dp_resources);

        return tb;
}