usb: dwc3: gadget: Properly check last unaligned/zero chain TRB

Current check for the last extra TRB for zero and unaligned transfers
does not account for isoc OUT. The last TRB of the Buffer Descriptor for
isoc OUT transfers will be retired with HWO=0. As a result, we won't
return early. The req->remaining will be updated to include the BUFSIZ
count of the extra TRB, and the actual number of transferred bytes
calculation will be wrong.

To fix this, check whether it's a short or zero packet and the last TRB
chain bit to return early.

Fixes: c6267a51639b ("usb: dwc3: gadget: align transfers to wMaxPacketSize")
Cc: <stable@vger.kernel.org>
Signed-off-by: Thinh Nguyen <thinhn@synopsys.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 679c12e145225899c1ac5ff3f4f8489d8552a928..06e22afdf3d14db31c13671e3b6eb2cc2a7c1581 100644 (file)
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -2259,7 +2259,7 @@ static int dwc3_gadget_ep_reclaim_completed_trb(struct dwc3_ep *dep,
         * with one TRB pending in the ring. We need to manually clear HWO bit
         * from that TRB.
         */
-       if ((req->zero || req->unaligned) && (trb->ctrl & DWC3_TRB_CTRL_HWO)) {
+       if ((req->zero || req->unaligned) && !(trb->ctrl & DWC3_TRB_CTRL_CHN)) {
                trb->ctrl &= ~DWC3_TRB_CTRL_HWO;
                return 1;
        }