thunderbolt: Add details to router uevent

Expose two environment variables for routers as part of the initial
uevent:

  USB4_VERSION=1.0
  USB4_TYPE=host|device|hub

Userspace can use this information to expose more details about each
connected device. Only USB4 devices have USB4_VERSION but all devices
have USB4_TYPE.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/thunderbolt/switch.c

@@ -1835,6 +1835,39 @@ static void tb_switch_release(struct device *dev)
 	kfree(sw);
 }
 
+static int tb_switch_uevent(struct device *dev, struct kobj_uevent_env *env)
+{
+	struct tb_switch *sw = tb_to_switch(dev);
+	const char *type;
+
+	if (sw->config.thunderbolt_version == USB4_VERSION_1_0) {
+		if (add_uevent_var(env, "USB4_VERSION=1.0"))
+			return -ENOMEM;
+	}
+
+	if (!tb_route(sw)) {
+		type = "host";
+	} else {
+		const struct tb_port *port;
+		bool hub = false;
+
+		/* Device is hub if it has any downstream ports */
+		tb_switch_for_each_port(sw, port) {
+			if (!port->disabled && !tb_is_upstream_port(port) &&
+			     tb_port_is_null(port)) {
+				hub = true;
+				break;
+			}
+		}
+
+		type = hub ? "hub" : "device";
+	}
+
+	if (add_uevent_var(env, "USB4_TYPE=%s", type))
+		return -ENOMEM;
+	return 0;
+}
+
 /*
  * Currently only need to provide the callbacks. Everything else is handled
  * in the connection manager.
@@ -1868,6 +1901,7 @@ static const struct dev_pm_ops tb_switch_pm_ops = {
 struct device_type tb_switch_type = {
 	.name = "thunderbolt_device",
 	.release = tb_switch_release,
+	.uevent = tb_switch_uevent,
 	.pm = &tb_switch_pm_ops,
 };