[PATCH 4.18 115/235] usb: xhci: fix interrupt transfer error happened on MTK platforms

[Greg Kroah-Hartman]

4.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Chunfeng Yun <chunfeng.yun@xxxxxxxxxxxx>

commit 0a3b53305c8ff427bbc1d9d5bd78524007f19600 upstream.

The MTK xHCI controller use some reserved bytes in endpoint context for
bandwidth scheduling, so need keep them in xhci_endpoint_copy();

The issue is introduced by:
commit f5249461b504 ("xhci: Clear the host side toggle manually when
endpoint is soft reset")
It resets endpoints and will drop bandwidth scheduling parameters used
by interrupt or isochronous endpoints on MTK xHCI controller.
Fixes: f5249461b504 ("xhci: Clear the host side toggle manually when
endpoint is soft reset")

Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Chunfeng Yun <chunfeng.yun@xxxxxxxxxxxx>
Tested-by: Sean Wang <sean.wang@xxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/usb/host/xhci-mem.c |    4 ++++
 1 file changed, 4 insertions(+)

--- a/drivers/usb/host/xhci-mem.c
+++ b/drivers/usb/host/xhci-mem.c
@@ -1613,6 +1613,10 @@ void xhci_endpoint_copy(struct xhci_hcd
 	in_ep_ctx->ep_info2 = out_ep_ctx->ep_info2;
 	in_ep_ctx->deq = out_ep_ctx->deq;
 	in_ep_ctx->tx_info = out_ep_ctx->tx_info;
+	if (xhci->quirks & XHCI_MTK_HOST) {
+		in_ep_ctx->reserved[0] = out_ep_ctx->reserved[0];
+		in_ep_ctx->reserved[1] = out_ep_ctx->reserved[1];
+	}
 }
 
 /* Copy output xhci_slot_ctx to the input xhci_slot_ctx.