From 1f856c46b0ba892911b571f1370bc1a9ccd80ac0 Mon Sep 17 00:00:00 2001
From: Jack Humbert <jack.humb@gmail.com>
Date: Fri, 14 Apr 2023 17:15:16 -0400
Subject: [PATCH] disable resetting when endpoint error occurs
---
drivers/usb/host/xhci-ring.c | 33 +++++++++++++++++++++++++++++++++
1 file changed, 33 insertions(+)
diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index b2cfd948f81..bd353aef3c5 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -473,6 +473,35 @@ union xhci_trb *xhci_wait_for_event(struct xhci_ctrl *ctrl, trb_type expected)
BUG();
}
+/*
+ * Issue reset endpoint command for an endpoint. This is required to recover
+ * a halted endpoint (e.g. due to a stall error).
+ * from https://github.com/agners/operating-system/blob/c3288801d7ff35c12d33d0e883dac246c4fc8a5a/buildroot-external/board/raspberrypi/patches/uboot/0005-usb-xhci-reset-endpoint-on-USB-stall.patch
+ */
+static void reset_ep(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;
+ u32 field;
+
+ // bit hard to type with this notification
+ //printf("Resetting EP...\n");
+ xhci_queue_command(ctrl, NULL, udev->slot_id, ep_index, TRB_RESET_EP);
+ event = xhci_wait_for_event(ctrl, TRB_COMPLETION);
+ field = le32_to_cpu(event->trans_event.flags);
+ BUG_ON(TRB_TO_SLOT_ID(field) != udev->slot_id);
+ xhci_acknowledge_event(ctrl);
+
+ xhci_queue_command(ctrl, (void *)((uintptr_t)ring->enqueue |
+ ring->cycle_state), udev->slot_id, ep_index, TRB_SET_DEQ);
+ event = xhci_wait_for_event(ctrl, TRB_COMPLETION);
+ 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
@@ -918,6 +947,10 @@ 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);
+ return -EPIPE;
+ }
/* Invalidate buffer to make it available to usb-core */
if (length > 0)
--
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