usb: xhci: Better error handling in abort_td()

If the xHC has a problem with our STOP ENDPOINT command, it is likely to
return a completion directly instead of first a transfer event for the
in-progress transfer. Handle that more gracefully.

We still BUG() on the error code, but at least we don't end up timing
out on the event and ending up with unexpected event errors.

Signed-off-by: Hector Martin <marcan@marcan.st>
Reviewed-by: Marek Vasut <marex@denx.de>

diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index d0960812a47b008312a624e0065525d01cb245a3..d21e76e0bdb63cf2494cb7274457ed8744685ae7 100644 (file)
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -466,7 +466,8 @@ union xhci_trb *xhci_wait_for_event(struct xhci_ctrl *ctrl, trb_type expected)
                        continue;
 
                type = TRB_FIELD_TO_TYPE(le32_to_cpu(event->event_cmd.flags));
-               if (type == expected)
+               if (type == expected ||
+                   (expected == TRB_NONE && type != TRB_PORT_STATUS))
                        return event;
 
                if (type == TRB_PORT_STATUS)
@@ -544,27 +545,36 @@ static void abort_td(struct usb_device *udev, int ep_index)
        struct xhci_ctrl *ctrl = xhci_get_ctrl(udev);
        struct xhci_ring *ring =  ctrl->devs[udev->slot_id]->eps[ep_index].ring;
        union xhci_trb *event;
+       trb_type type;
        u64 addr;
        u32 field;
 
        xhci_queue_command(ctrl, 0, udev->slot_id, ep_index, TRB_STOP_RING);
 
-       event = xhci_wait_for_event(ctrl, TRB_TRANSFER);
+       event = xhci_wait_for_event(ctrl, TRB_NONE);
        if (!event)
                return;
 
-       field = le32_to_cpu(event->trans_event.flags);
-       BUG_ON(TRB_TO_SLOT_ID(field) != udev->slot_id);
-       BUG_ON(TRB_TO_EP_INDEX(field) != ep_index);
-       BUG_ON(GET_COMP_CODE(le32_to_cpu(event->trans_event.transfer_len
-               != COMP_STOP)));
-       xhci_acknowledge_event(ctrl);
+       type = TRB_FIELD_TO_TYPE(le32_to_cpu(event->event_cmd.flags));
+       if (type == TRB_TRANSFER) {
+               field = le32_to_cpu(event->trans_event.flags);
+               BUG_ON(TRB_TO_SLOT_ID(field) != udev->slot_id);
+               BUG_ON(TRB_TO_EP_INDEX(field) != ep_index);
+               BUG_ON(GET_COMP_CODE(le32_to_cpu(event->trans_event.transfer_len
+                       != COMP_STOP)));
+               xhci_acknowledge_event(ctrl);
 
-       event = xhci_wait_for_event(ctrl, TRB_COMPLETION);
-       if (!event)
-               return;
+               event = xhci_wait_for_event(ctrl, TRB_COMPLETION);
+               if (!event)
+                       return;
+               type = TRB_FIELD_TO_TYPE(le32_to_cpu(event->event_cmd.flags));
 
-       BUG_ON(TRB_TO_SLOT_ID(le32_to_cpu(event->event_cmd.flags))
+       } else {
+               printf("abort_td: Expected a TRB_TRANSFER TRB first\n");
+       }
+
+       BUG_ON(type != TRB_COMPLETION ||
+               TRB_TO_SLOT_ID(le32_to_cpu(event->event_cmd.flags))
                != udev->slot_id || GET_COMP_CODE(le32_to_cpu(
                event->event_cmd.status)) != COMP_SUCCESS);
        xhci_acknowledge_event(ctrl);

diff --git a/include/usb/xhci.h b/include/usb/xhci.h
index 4a4ac10229ac94083bbf1c581804142ff8bf810d..04d16a256bbd5639f2bd89554feb7a04ac6799a7 100644 (file)
--- a/include/usb/xhci.h
+++ b/include/usb/xhci.h
@@ -901,6 +901,8 @@ union xhci_trb {
 
 /* TRB type IDs */
 typedef enum {
+       /* reserved, used as a software sentinel */
+       TRB_NONE = 0,
        /* bulk, interrupt, isoc scatter/gather, and control data stage */
        TRB_NORMAL = 1,
        /* setup stage for control transfers */