[PATCH v6 part1 4/8] usb: assign default peer ports for root hubs

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Assume that the peer of a superspeed port is the port with the same id
on the shared_hcd root hub.  This identification scheme is required of
external hubs by the USB3 spec [1].  However, for root hubs, tier mismatch
may be in effect [2].  Tier mismatch can only be enumerated via platform
firmware.  For now, simply perform the nominal association.

Once the root hub is marked as unregistered we block attempts to walk
the ->shared_hcd pointer to find a root-peer port.

[1]: usb 3.1 section 10.3.3
[2]: xhci 1.1 appendix D

Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
---
 drivers/usb/core/hcd.c  |    8 ++++
 drivers/usb/core/hub.h  |    2 +
 drivers/usb/core/port.c |   90 ++++++++++++++++++++++++++++++++++++++++++++---
 drivers/usb/core/usb.h  |    3 ++
 4 files changed, 97 insertions(+), 6 deletions(-)

diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c
index 2518c3250750..e380b8a80830 100644
--- a/drivers/usb/core/hcd.c
+++ b/drivers/usb/core/hcd.c
@@ -2778,9 +2778,17 @@ void usb_remove_hcd(struct usb_hcd *hcd)
 		hcd->state = HC_STATE_QUIESCING;
 
 	dev_dbg(hcd->self.controller, "roothub graceful disconnect\n");
+
+	/*
+	 * Flush + disable peering operations, and atomically update the
+	 * hcd state relative to other root hub state
+	 * changes/evaluations
+	 */
+	mutex_lock(&usb_port_peer_mutex);
 	spin_lock_irq (&hcd_root_hub_lock);
 	hcd->rh_registered = 0;
 	spin_unlock_irq (&hcd_root_hub_lock);
+	mutex_unlock(&usb_port_peer_mutex);
 
 #ifdef CONFIG_PM_RUNTIME
 	cancel_work_sync(&hcd->wakeup_work);
diff --git a/drivers/usb/core/hub.h b/drivers/usb/core/hub.h
index baf5b48b79f7..d51feb68165b 100644
--- a/drivers/usb/core/hub.h
+++ b/drivers/usb/core/hub.h
@@ -81,6 +81,7 @@ struct usb_hub {
  * @child: usb device attached to the port
  * @dev: generic device interface
  * @port_owner: port's owner
+ * @peer: related usb2 and usb3 ports (share the same connector)
  * @connect_type: port's connect type
  * @portnum: port index num based one
  * @power_is_on: port's power state
@@ -90,6 +91,7 @@ struct usb_port {
 	struct usb_device *child;
 	struct device dev;
 	struct dev_state *port_owner;
+	struct usb_port *peer;
 	enum usb_port_connect_type connect_type;
 	u8 portnum;
 	unsigned power_is_on:1;
diff --git a/drivers/usb/core/port.c b/drivers/usb/core/port.c
index afe0d894c907..d8bea408a2f2 100644
--- a/drivers/usb/core/port.c
+++ b/drivers/usb/core/port.c
@@ -21,6 +21,9 @@
 
 #include "hub.h"
 
+/* synchronize hub-port add/remove and peering operations */
+DEFINE_MUTEX(usb_port_peer_mutex);
+
 static const struct attribute_group *port_dev_group[];
 
 static ssize_t connect_type_show(struct device *dev,
@@ -151,9 +154,71 @@ static struct device_driver usb_port_driver = {
 	.owner = THIS_MODULE,
 };
 
+/*
+ * Set the default peer port for root hubs.  Assumes the primary_hcd is
+ * registered first
+ */
+static struct usb_port *find_default_peer(struct usb_hub *hub, int port1)
+{
+	struct usb_device *hdev = hub->hdev;
+	struct usb_port *peer = NULL;
+
+	if (!hub || hub->disconnected)
+		return NULL;
+
+	if (!hdev->parent) {
+		struct usb_hub *peer_hub;
+		struct usb_device *peer_hdev;
+		struct usb_hcd *hcd = bus_to_hcd(hdev->bus);
+		struct usb_hcd *peer_hcd = hcd->primary_hcd;
+
+		if (!peer_hcd || !peer_hcd->rh_registered
+				|| !hcd->rh_registered
+				|| hcd == peer_hcd)
+			return NULL;
+
+		peer_hdev = peer_hcd->self.root_hub;
+		peer_hub = usb_hub_to_struct_hub(peer_hdev);
+		if (peer_hub && port1 <= peer_hdev->maxchild)
+			peer = peer_hub->ports[port1 - 1];
+	}
+
+	return peer;
+}
+
+static void link_peers(struct usb_port *left, struct usb_port *right)
+{
+	if (left->peer == right && right->peer == left)
+		return;
+
+	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;
+	}
+
+	left->peer = right;
+	right->peer = left;
+}
+
+static void unlink_peers(struct usb_port *left, struct usb_port *right)
+{
+	WARN(right->peer != left || left->peer != right,
+			"%s and %s are not peers?\n",
+			dev_name(&left->dev), dev_name(&right->dev));
+
+	right->peer = NULL;
+	left->peer = NULL;
+}
+
 int usb_hub_create_port_device(struct usb_hub *hub, int port1)
 {
-	struct usb_port *port_dev = NULL;
+	struct usb_port *port_dev, *peer = NULL;
 	int retval;
 
 	port_dev = kzalloc(sizeof(*port_dev), GFP_KERNEL);
@@ -162,7 +227,6 @@ int usb_hub_create_port_device(struct usb_hub *hub, int port1)
 		goto exit;
 	}
 
-	hub->ports[port1 - 1] = port_dev;
 	port_dev->portnum = port1;
 	port_dev->power_is_on = true;
 	port_dev->dev.parent = hub->intfdev;
@@ -171,7 +235,15 @@ int usb_hub_create_port_device(struct usb_hub *hub, int port1)
 	port_dev->dev.driver = &usb_port_driver;
 	dev_set_name(&port_dev->dev, "%s-port%d", dev_name(&hub->hdev->dev),
 			port1);
+
+	mutex_lock(&usb_port_peer_mutex);
+	hub->ports[port1 - 1] = port_dev;
 	retval = device_register(&port_dev->dev);
+	if (retval == 0)
+		peer = find_default_peer(hub, port1);
+	if (peer)
+		link_peers(port_dev, peer);
+	mutex_unlock(&usb_port_peer_mutex);
 	if (retval)
 		goto error_register;
 
@@ -196,9 +268,15 @@ 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;
+
+	mutex_lock(&usb_port_peer_mutex);
+	peer = port_dev->peer;
+	if (peer)
+		unlink_peers(port_dev, peer);
+	device_unregister(&port_dev->dev);
+	mutex_unlock(&usb_port_peer_mutex);
 }
-
diff --git a/drivers/usb/core/usb.h b/drivers/usb/core/usb.h
index 28f272884c0d..8a1acf59d498 100644
--- a/drivers/usb/core/usb.h
+++ b/drivers/usb/core/usb.h
@@ -157,6 +157,9 @@ static inline int is_usb_device_driver(struct device_driver *drv)
 			for_devices;
 }
 
+/* port peering lock shared between port, hub, and hcd */
+extern struct mutex usb_port_peer_mutex;
+
 /* for labeling diagnostics */
 extern const char *usbcore_name;
 

--
To unsubscribe from this list: send the line "unsubscribe linux-usb" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html




[Index of Archives]     [Linux Media]     [Linux Input]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]     [Old Linux USB Devel Archive]

  Powered by Linux