This ports U-Boot commit d5daa02d8d9e7c403a3339db1966e8413e64e408: | Author: Stefan Agner <[email protected]> | AuthorDate: Mon Sep 27 14:42:58 2021 +0200 | | usb: xhci: reset endpoint on USB stall | | There are devices which cause a USB stall when trying to read strings. | Specifically Arduino Mega R3 stalls when trying to read the product | string. | | The stall currently remains unhandled, and subsequent retries submit new | transfers on a stopped endpoint which ultimately cause a crash in | abort_td(): | WARN halted endpoint, queueing URB anyway. | XHCI control transfer timed out, aborting... | Unexpected XHCI event TRB, skipping... (3affe040 00000000 13000000 02008401) | BUG at drivers/usb/host/xhci-ring.c:505/abort_td()! | BUG! | resetting ... | | Linux seems to be able to recover from the stall by issuing a | TRB_RESET_EP command. | | Introduce reset_ep() which issues a TRB_RESET_EP followed by setting the | transfer ring dequeue pointer via TRB_SET_DEQ. This allows to properly | recover from a USB stall error and continue communicating with the USB | device. | | Signed-off-by: Stefan Agner <[email protected]>
Signed-off-by: Ahmad Fatoum <[email protected]> --- drivers/usb/host/xhci-ring.c | 40 ++++++++++++++++++++++++++++++++++++ 1 file changed, 40 insertions(+) diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c index c645285da7fc..056613445330 100644 --- a/drivers/usb/host/xhci-ring.c +++ b/drivers/usb/host/xhci-ring.c @@ -500,6 +500,42 @@ union xhci_trb *xhci_wait_for_event(struct xhci_ctrl *ctrl, trb_type expected, BUG(); } +/* + * Send reset endpoint command for given endpoint. This recovers from a + * halted endpoint (e.g. due to a stall error). + */ +static void reset_ep(struct usb_device *udev, int ep_index, unsigned int timeout_ms) +{ + 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; + u64 addr; + u32 field; + + dev_info(&udev->dev, "Resetting EP %d...\n", ep_index); + + xhci_queue_command(ctrl, 0, udev->slot_id, ep_index, TRB_RESET_EP); + event = xhci_wait_for_event(ctrl, TRB_COMPLETION, timeout_ms); + if (!event) + return; + + field = le32_to_cpu(event->trans_event.flags); + BUG_ON(TRB_TO_SLOT_ID(field) != udev->slot_id); + xhci_acknowledge_event(ctrl); + + addr = xhci_trb_virt_to_dma(ring->enq_seg, + (void *)((uintptr_t)ring->enqueue | ring->cycle_state)); + xhci_queue_command(ctrl, addr, udev->slot_id, ep_index, TRB_SET_DEQ); + event = xhci_wait_for_event(ctrl, TRB_COMPLETION, timeout_ms); + if (!event) + return; + + BUG_ON(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); +} + /* * Stops transfer processing for an endpoint and throws away all unprocessed * TRBs by setting the xHC's dequeue pointer to our enqueue pointer. The next @@ -979,6 +1015,10 @@ int xhci_ctrl_tx(struct usb_device *udev, unsigned long pipe, record_transfer_result(udev, event, length); xhci_acknowledge_event(ctrl); + if (udev->status == USB_ST_STALLED) { + reset_ep(udev, ep_index, timeout_ms); + return -EPIPE; + } /* Invalidate buffer to make it available to usb-core */ if (length > 0) -- 2.39.2
