1 files changed, 31 insertions, 11 deletions

diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 716f4f051..05a5300aa 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -1897,7 +1897,8 @@ static void dwc3_gadget_free_endpoints(struct dwc3 *dwc)
 
 static int __dwc3_cleanup_done_trbs(struct dwc3 *dwc, struct dwc3_ep *dep,
 		struct dwc3_request *req, struct dwc3_trb *trb,
-		const struct dwc3_event_depevt *event, int status)
+		const struct dwc3_event_depevt *event, int status,
+		int chain)
 {
 	unsigned int		count;
 	unsigned int		s_pkt = 0;
@@ -1905,6 +1906,19 @@ static int __dwc3_cleanup_done_trbs(struct dwc3 *dwc, struct dwc3_ep *dep,
 
 	trace_dwc3_complete_trb(dep, trb);
 
+	/*
+	 * If we're in the middle of series of chained TRBs and we
+	 * receive a short transfer along the way, DWC3 will skip
+	 * through all TRBs including the last TRB in the chain (the
+	 * where CHN bit is zero. DWC3 will also avoid clearing HWO
+	 * bit and SW has to do it manually.
+	 *
+	 * We're going to do that here to avoid problems of HW trying
+	 * to use bogus TRBs for transfers.
+	 */
+	if (chain && (trb->ctrl & DWC3_TRB_CTRL_HWO))
+		trb->ctrl &= ~DWC3_TRB_CTRL_HWO;
+
 	if ((trb->ctrl & DWC3_TRB_CTRL_HWO) && status != -ESHUTDOWN)
 		/*
 		 * We continue despite the error. There is not much we
@@ -1916,6 +1930,7 @@ static int __dwc3_cleanup_done_trbs(struct dwc3 *dwc, struct dwc3_ep *dep,
 		 */
 		dev_err(dwc->dev, "%s's TRB (%p) still owned by HW\n",
 				dep->name, trb);
+
 	count = trb->size & DWC3_TRB_SIZE_MASK;
 
 	if (dep->direction) {
@@ -1954,15 +1969,7 @@ static int __dwc3_cleanup_done_trbs(struct dwc3 *dwc, struct dwc3_ep *dep,
 			s_pkt = 1;
 	}
 
-	/*
-	 * We assume here we will always receive the entire data block
-	 * which we should receive. Meaning, if we program RX to
-	 * receive 4K but we receive only 2K, we assume that's all we
-	 * should receive and we simply bounce the request back to the
-	 * gadget driver for further processing.
-	 */
-	req->request.actual += req->request.length - count;
-	if (s_pkt)
+	if (s_pkt && !chain)
 		return 1;
 	if ((event->status & DEPEVT_STATUS_LST) &&
 			(trb->ctrl & (DWC3_TRB_CTRL_LST |
@@ -1981,13 +1988,17 @@ static int dwc3_cleanup_done_reqs(struct dwc3 *dwc, struct dwc3_ep *dep,
 	struct dwc3_trb		*trb;
 	unsigned int		slot;
 	unsigned int		i;
+	int			count = 0;
 	int			ret;
 
 	do {
+		int chain;
+
 		req = next_request(&dep->started_list);
 		if (WARN_ON_ONCE(!req))
 			return 1;
 
+		chain = req->request.num_mapped_sgs > 0;
 		i = 0;
 		do {
 			slot = req->first_trb_index + i;
@@ -1995,13 +2006,22 @@ static int dwc3_cleanup_done_reqs(struct dwc3 *dwc, struct dwc3_ep *dep,
 				slot++;
 			slot %= DWC3_TRB_NUM;
 			trb = &dep->trb_pool[slot];
+			count += trb->size & DWC3_TRB_SIZE_MASK;
 
 			ret = __dwc3_cleanup_done_trbs(dwc, dep, req, trb,
-					event, status);
+					event, status, chain);
 			if (ret)
 				break;
 		} while (++i < req->request.num_mapped_sgs);
 
+		/*
+		 * We assume here we will always receive the entire data block
+		 * which we should receive. Meaning, if we program RX to
+		 * receive 4K but we receive only 2K, we assume that's all we
+		 * should receive and we simply bounce the request back to the
+		 * gadget driver for further processing.
+		 */
+		req->request.actual += req->request.length - count;
 		dwc3_gadget_giveback(dep, req, status);
 
 		if (ret)