1 files changed, 268 insertions, 21 deletions

diff --git a/drivers/usb/core/port.c b/drivers/usb/core/port.c
index 51542f852393..62036faf56c0 100644
--- a/drivers/usb/core/port.c
+++ b/drivers/usb/core/port.c
@@ -76,17 +76,29 @@ static int usb_port_runtime_resume(struct device *dev)
 	struct usb_device *hdev = to_usb_device(dev->parent->parent);
 	struct usb_interface *intf = to_usb_interface(dev->parent);
 	struct usb_hub *hub = usb_hub_to_struct_hub(hdev);
+	struct usb_device *udev = port_dev->child;
+	struct usb_port *peer = port_dev->peer;
 	int port1 = port_dev->portnum;
 	int retval;
 
 	if (!hub)
 		return -EINVAL;
+	if (hub->in_reset) {
+		set_bit(port1, hub->power_bits);
+		return 0;
+	}
 
-	usb_autopm_get_interface(intf);
-	set_bit(port1, hub->busy_bits);
+	/*
+	 * Power on our usb3 peer before this usb2 port to prevent a usb3
+	 * device from degrading to its usb2 connection
+	 */
+	if (!port_dev->is_superspeed && peer)
+		pm_runtime_get_sync(&peer->dev);
 
+	usb_autopm_get_interface(intf);
 	retval = usb_hub_set_port_power(hdev, hub, port1, true);
-	if (port_dev->child && !retval) {
+	msleep(hub_power_on_good_delay(hub));
+	if (udev && !retval) {
 		/*
 		 * Attempt to wait for usb hub port to be reconnected in order
 		 * to make the resume procedure successful.  The device may have
@@ -97,12 +109,17 @@ static int usb_port_runtime_resume(struct device *dev)
 		if (retval < 0)
 			dev_dbg(&port_dev->dev, "can't get reconnection after setting port  power on, status %d\n",
 					retval);
-		usb_clear_port_feature(hdev, port1, USB_PORT_FEAT_C_ENABLE);
 		retval = 0;
+
+		/* Force the child awake to revalidate after the power loss. */
+		if (!test_and_set_bit(port1, hub->child_usage_bits)) {
+			pm_runtime_get_noresume(&port_dev->dev);
+			pm_request_resume(&udev->dev);
+		}
 	}
 
-	clear_bit(port1, hub->busy_bits);
 	usb_autopm_put_interface(intf);
+
 	return retval;
 }
 
@@ -112,23 +129,34 @@ static int usb_port_runtime_suspend(struct device *dev)
 	struct usb_device *hdev = to_usb_device(dev->parent->parent);
 	struct usb_interface *intf = to_usb_interface(dev->parent);
 	struct usb_hub *hub = usb_hub_to_struct_hub(hdev);
+	struct usb_port *peer = port_dev->peer;
 	int port1 = port_dev->portnum;
 	int retval;
 
 	if (!hub)
 		return -EINVAL;
+	if (hub->in_reset)
+		return -EBUSY;
 
 	if (dev_pm_qos_flags(&port_dev->dev, PM_QOS_FLAG_NO_POWER_OFF)
 			== PM_QOS_FLAGS_ALL)
 		return -EAGAIN;
 
 	usb_autopm_get_interface(intf);
-	set_bit(port1, hub->busy_bits);
 	retval = usb_hub_set_port_power(hdev, hub, port1, false);
 	usb_clear_port_feature(hdev, port1, USB_PORT_FEAT_C_CONNECTION);
-	usb_clear_port_feature(hdev, port1,	USB_PORT_FEAT_C_ENABLE);
-	clear_bit(port1, hub->busy_bits);
+	if (!port_dev->is_superspeed)
+		usb_clear_port_feature(hdev, port1, USB_PORT_FEAT_C_ENABLE);
 	usb_autopm_put_interface(intf);
+
+	/*
+	 * Our peer usb3 port may now be able to suspend, so
+	 * asynchronously queue a suspend request to observe that this
+	 * usb2 port is now off.
+	 */
+	if (!port_dev->is_superspeed && peer)
+		pm_runtime_put(&peer->dev);
+
 	return retval;
 }
 #endif
@@ -146,9 +174,215 @@ struct device_type usb_port_device_type = {
 	.pm =		&usb_port_pm_ops,
 };
 
+static struct device_driver usb_port_driver = {
+	.name = "usb",
+	.owner = THIS_MODULE,
+};
+
+static int link_peers(struct usb_port *left, struct usb_port *right)
+{
+	struct usb_port *ss_port, *hs_port;
+	int rc;
+
+	if (left->peer == right && right->peer == left)
+		return 0;
+
+	if (left->peer || right->peer) {
+		struct usb_port *lpeer = left->peer;
+		struct usb_port *rpeer = right->peer;
+
+		WARN(1, "failed to peer %s and %s (%s -> %p) (%s -> %p)\n",
+			dev_name(&left->dev), dev_name(&right->dev),
+			dev_name(&left->dev), lpeer,
+			dev_name(&right->dev), rpeer);
+		return -EBUSY;
+	}
+
+	rc = sysfs_create_link(&left->dev.kobj, &right->dev.kobj, "peer");
+	if (rc)
+		return rc;
+	rc = sysfs_create_link(&right->dev.kobj, &left->dev.kobj, "peer");
+	if (rc) {
+		sysfs_remove_link(&left->dev.kobj, "peer");
+		return rc;
+	}
+
+	/*
+	 * We need to wake the HiSpeed port to make sure we don't race
+	 * setting ->peer with usb_port_runtime_suspend().  Otherwise we
+	 * may miss a suspend event for the SuperSpeed port.
+	 */
+	if (left->is_superspeed) {
+		ss_port = left;
+		WARN_ON(right->is_superspeed);
+		hs_port = right;
+	} else {
+		ss_port = right;
+		WARN_ON(!right->is_superspeed);
+		hs_port = left;
+	}
+	pm_runtime_get_sync(&hs_port->dev);
+
+	left->peer = right;
+	right->peer = left;
+
+	/*
+	 * The SuperSpeed reference is dropped when the HiSpeed port in
+	 * this relationship suspends, i.e. when it is safe to allow a
+	 * SuperSpeed connection to drop since there is no risk of a
+	 * device degrading to its powered-off HiSpeed connection.
+	 *
+	 * Also, drop the HiSpeed ref taken above.
+	 */
+	pm_runtime_get_sync(&ss_port->dev);
+	pm_runtime_put(&hs_port->dev);
+
+	return 0;
+}
+
+static void link_peers_report(struct usb_port *left, struct usb_port *right)
+{
+	int rc;
+
+	rc = link_peers(left, right);
+	if (rc == 0) {
+		dev_dbg(&left->dev, "peered to %s\n", dev_name(&right->dev));
+	} else {
+		dev_warn(&left->dev, "failed to peer to %s (%d)\n",
+				dev_name(&right->dev), rc);
+		pr_warn_once("usb: port power management may be unreliable\n");
+	}
+}
+
+static void unlink_peers(struct usb_port *left, struct usb_port *right)
+{
+	struct usb_port *ss_port, *hs_port;
+
+	WARN(right->peer != left || left->peer != right,
+			"%s and %s are not peers?\n",
+			dev_name(&left->dev), dev_name(&right->dev));
+
+	/*
+	 * We wake the HiSpeed port to make sure we don't race its
+	 * usb_port_runtime_resume() event which takes a SuperSpeed ref
+	 * when ->peer is !NULL.
+	 */
+	if (left->is_superspeed) {
+		ss_port = left;
+		hs_port = right;
+	} else {
+		ss_port = right;
+		hs_port = left;
+	}
+
+	pm_runtime_get_sync(&hs_port->dev);
+
+	sysfs_remove_link(&left->dev.kobj, "peer");
+	right->peer = NULL;
+	sysfs_remove_link(&right->dev.kobj, "peer");
+	left->peer = NULL;
+
+	/* Drop the SuperSpeed ref held on behalf of the active HiSpeed port */
+	pm_runtime_put(&ss_port->dev);
+
+	/* Drop the ref taken above */
+	pm_runtime_put(&hs_port->dev);
+}
+
+/*
+ * For each usb hub device in the system check to see if it is in the
+ * peer domain of the given port_dev, and if it is check to see if it
+ * has a port that matches the given port by location
+ */
+static int match_location(struct usb_device *peer_hdev, void *p)
+{
+	int port1;
+	struct usb_hcd *hcd, *peer_hcd;
+	struct usb_port *port_dev = p, *peer;
+	struct usb_hub *peer_hub = usb_hub_to_struct_hub(peer_hdev);
+	struct usb_device *hdev = to_usb_device(port_dev->dev.parent->parent);
+
+	if (!peer_hub)
+		return 0;
+
+	hcd = bus_to_hcd(hdev->bus);
+	peer_hcd = bus_to_hcd(peer_hdev->bus);
+	/* peer_hcd is provisional until we verify it against the known peer */
+	if (peer_hcd != hcd->shared_hcd)
+		return 0;
+
+	for (port1 = 1; port1 <= peer_hdev->maxchild; port1++) {
+		peer = peer_hub->ports[port1 - 1];
+		if (peer && peer->location == port_dev->location) {
+			link_peers_report(port_dev, peer);
+			return 1; /* done */
+		}
+	}
+
+	return 0;
+}
+
+/*
+ * Find the peer port either via explicit platform firmware "location"
+ * data, the peer hcd for root hubs, or the upstream peer relationship
+ * for all other hubs.
+ */
+static void find_and_link_peer(struct usb_hub *hub, int port1)
+{
+	struct usb_port *port_dev = hub->ports[port1 - 1], *peer;
+	struct usb_device *hdev = hub->hdev;
+	struct usb_device *peer_hdev;
+	struct usb_hub *peer_hub;
+
+	/*
+	 * If location data is available then we can only peer this port
+	 * by a location match, not the default peer (lest we create a
+	 * situation where we need to go back and undo a default peering
+	 * when the port is later peered by location data)
+	 */
+	if (port_dev->location) {
+		/* we link the peer in match_location() if found */
+		usb_for_each_dev(port_dev, match_location);
+		return;
+	} else if (!hdev->parent) {
+		struct usb_hcd *hcd = bus_to_hcd(hdev->bus);
+		struct usb_hcd *peer_hcd = hcd->shared_hcd;
+
+		if (!peer_hcd)
+			return;
+
+		peer_hdev = peer_hcd->self.root_hub;
+	} else {
+		struct usb_port *upstream;
+		struct usb_device *parent = hdev->parent;
+		struct usb_hub *parent_hub = usb_hub_to_struct_hub(parent);
+
+		if (!parent_hub)
+			return;
+
+		upstream = parent_hub->ports[hdev->portnum - 1];
+		if (!upstream || !upstream->peer)
+			return;
+
+		peer_hdev = upstream->peer->child;
+	}
+
+	peer_hub = usb_hub_to_struct_hub(peer_hdev);
+	if (!peer_hub || port1 > peer_hdev->maxchild)
+		return;
+
+	/*
+	 * we found a valid default peer, last check is to make sure it
+	 * does not have location data
+	 */
+	peer = peer_hub->ports[port1 - 1];
+	if (peer && peer->location == 0)
+		link_peers_report(port_dev, peer);
+}
+
 int usb_hub_create_port_device(struct usb_hub *hub, int port1)
 {
-	struct usb_port *port_dev = NULL;
+	struct usb_port *port_dev;
 	int retval;
 
 	port_dev = kzalloc(sizeof(*port_dev), GFP_KERNEL);
@@ -159,24 +393,33 @@ int usb_hub_create_port_device(struct usb_hub *hub, int port1)
 
 	hub->ports[port1 - 1] = port_dev;
 	port_dev->portnum = port1;
-	port_dev->power_is_on = true;
+	set_bit(port1, hub->power_bits);
 	port_dev->dev.parent = hub->intfdev;
 	port_dev->dev.groups = port_dev_group;
 	port_dev->dev.type = &usb_port_device_type;
-	dev_set_name(&port_dev->dev, "port%d", port1);
-
+	port_dev->dev.driver = &usb_port_driver;
+	if (hub_is_superspeed(hub->hdev))
+		port_dev->is_superspeed = 1;
+	dev_set_name(&port_dev->dev, "%s-port%d", dev_name(&hub->hdev->dev),
+			port1);
+	mutex_init(&port_dev->status_lock);
 	retval = device_register(&port_dev->dev);
 	if (retval)
 		goto error_register;
 
+	find_and_link_peer(hub, port1);
+
 	pm_runtime_set_active(&port_dev->dev);
 
-	/* It would be dangerous if user space couldn't
-	 * prevent usb device from being powered off. So don't
-	 * enable port runtime pm if failed to expose port's pm qos.
+	/*
+	 * Do not enable port runtime pm if the hub does not support
+	 * power switching.  Also, userspace must have final say of
+	 * whether a port is permitted to power-off.  Do not enable
+	 * runtime pm if we fail to expose pm_qos_no_power_off.
 	 */
-	if (!dev_pm_qos_expose_flags(&port_dev->dev,
-			PM_QOS_FLAG_NO_POWER_OFF))
+	if (hub_is_port_power_switchable(hub)
+			&& dev_pm_qos_expose_flags(&port_dev->dev,
+			PM_QOS_FLAG_NO_POWER_OFF) == 0)
 		pm_runtime_enable(&port_dev->dev);
 
 	device_enable_async_suspend(&port_dev->dev);
@@ -188,9 +431,13 @@ exit:
 	return retval;
 }
 
-void usb_hub_remove_port_device(struct usb_hub *hub,
-				       int port1)
+void usb_hub_remove_port_device(struct usb_hub *hub, int port1)
 {
-	device_unregister(&hub->ports[port1 - 1]->dev);
-}
+	struct usb_port *port_dev = hub->ports[port1 - 1];
+	struct usb_port *peer;
 
+	peer = port_dev->peer;
+	if (peer)
+		unlink_peers(port_dev, peer);
+	device_unregister(&port_dev->dev);
+}