Given that root hub port peers are already established, external hub peer
ports can be determined by traversing the device topology:
1/ ascend to the parent hub and find the upstream port_dev
2/ walk ->peer to find the peer port
3/ descend to the peer hub via ->child
4/ find the port with the matching port id
Note that this assumes the port labelling scheme required by the
specification [1].
[1]: usb3 3.1 section 10.3.3
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
---
drivers/usb/core/port.c | 22 ++++++++++++++++++++--
1 files changed, 20 insertions(+), 2 deletions(-)
diff --git a/drivers/usb/core/port.c b/drivers/usb/core/port.c
index d57fb01bbc1c..068d495007e1 100644
--- a/drivers/usb/core/port.c
+++ b/drivers/usb/core/port.c
@@ -155,11 +155,11 @@ struct device_type usb_port_device_type = {
static struct usb_port *find_default_peer(struct usb_hub *hub, int port1)
{
struct usb_device *hdev = hub->hdev;
+ struct usb_device *peer_hdev;
struct usb_port *peer = NULL;
+ struct usb_hub *peer_hub;
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;
@@ -170,6 +170,24 @@ static struct usb_port *find_default_peer(struct usb_hub *hub, int port1)
peer_hub = usb_hub_to_struct_hub(peer_hdev);
if (peer_hub && port1 <= peer_hdev->maxchild)
peer = peer_hub->ports[port1 - 1];
+ } 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 NULL;
+
+ upstream = parent_hub->ports[hdev->portnum - 1];
+ if (!upstream->peer)
+ return NULL;
+
+ peer_hdev = upstream->peer->child;
+ peer_hub = usb_hub_to_struct_hub(peer_hdev);
+ if (!peer_hub || port1 > peer_hdev->maxchild)
+ return NULL;
+
+ peer = peer_hub->ports[port1 - 1];
}
return peer;
--
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
