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 labeling scheme required by the
specification [1].
[1]: usb3 3.1 section 10.3.3
Acked-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
---
drivers/usb/core/port.c | 32 ++++++++++++++++++++++++--------
1 files changed, 24 insertions(+), 8 deletions(-)
diff --git a/drivers/usb/core/port.c b/drivers/usb/core/port.c
index 5ecdbf31dfcb..9b7496b52f2a 100644
--- a/drivers/usb/core/port.c
+++ b/drivers/usb/core/port.c
@@ -187,15 +187,18 @@ static void unlink_peers(struct usb_port *left, struct usb_port *right)
left->peer = NULL;
}
-/* set the default peer port for root hubs */
+/*
+ * Set the default peer port for root hubs, or via 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 (!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->shared_hcd;
@@ -203,15 +206,28 @@ static void find_and_link_peer(struct usb_hub *hub, int port1)
return;
peer_hdev = peer_hcd->self.root_hub;
- peer_hub = usb_hub_to_struct_hub(peer_hdev);
- if (!peer_hub || port1 > peer_hdev->maxchild)
+ } 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;
- peer = peer_hub->ports[port1 - 1];
+ upstream = parent_hub->ports[hdev->portnum - 1];
+ if (!upstream || !upstream->peer)
+ return;
- if (peer)
- link_peers(port_dev, peer);
+ peer_hdev = upstream->peer->child;
}
+
+ peer_hub = usb_hub_to_struct_hub(peer_hdev);
+ if (!peer_hub || port1 > peer_hdev->maxchild)
+ return;
+
+ peer = peer_hub->ports[port1 - 1];
+ if (peer)
+ link_peers(port_dev, peer);
}
int usb_hub_create_port_device(struct usb_hub *hub, int port1)
--
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