path: root/drivers/thunderbolt/tb.c

// 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 <linux/pm_runtime.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.
 * @remove_work: Work used to remove any unplugged routers after
 *		 runtime resume
 */
struct tb_cm {
	struct list_head tunnel_list;
	struct list_head dp_resources;
	bool hotplug_active;
	struct delayed_work remove_work;
};

static inline struct tb *tcm_to_tb(struct tb_cm *tcm)
{
	return ((void *)tcm - sizeof(struct tb));
}

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 int tb_port_configure_xdomain(struct tb_port *port)
{
	/*
	 * XDomain paths currently only support single lane so we must
	 * disable the other lane according to USB4 spec.
	 */
	tb_port_disable(port->dual_link_port);

	if (tb_switch_is_usb4(port->sw))
		return usb4_port_configure_xdomain(port);
	return tb_lc_configure_xdomain(port);
}

static void tb_port_unconfigure_xdomain(struct tb_port *port)
{
	if (tb_switch_is_usb4(port->sw))
		usb4_port_unconfigure_xdomain(port);
	else
		tb_lc_unconfigure_xdomain(port);

	tb_port_enable(port->dual_link_port);
}

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_port_configure_xdomain(port);
		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 && !tb_usb3_port_is_enabled(down))
		return down;
	return NULL;
}

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 struct tb_tunnel *tb_find_first_usb3_tunnel(struct tb *tb,
						   struct tb_port *src_port,
						   struct tb_port *dst_port)
{
	struct tb_port *port, *usb3_down;
	struct tb_switch *sw;

	/* Pick the router that is deepest in the topology */
	if (dst_port->sw->config.depth > src_port->sw->config.depth)
		sw = dst_port->sw;
	else
		sw = src_port->sw;

	/* Can't be the host router */
	if (sw == tb->root_switch)
		return NULL;

	/* Find the downstream USB4 port that leads to this router */
	port = tb_port_at(tb_route(sw), tb->root_switch);
	/* Find the corresponding host router USB3 downstream port */
	usb3_down = usb4_switch_map_usb3_down(tb->root_switch, port);
	if (!usb3_down)
		return NULL;

	return tb_find_tunnel(tb, TB_TUNNEL_USB3, usb3_down, NULL);
}

static int tb_available_bandwidth(struct tb *tb, struct tb_port *src_port,
	struct tb_port *dst_port, int *available_up, int *available_down)
{
	int usb3_consumed_up, usb3_consumed_down, ret;
	struct tb_cm *tcm = tb_priv(tb);
	struct tb_tunnel *tunnel;
	struct tb_port *port