1 files changed, 33 insertions, 22 deletions

diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 8f8c2157910e..1f5597ef945d 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -829,7 +829,7 @@ static void dwc3_prepare_one_trb(struct dwc3_ep *dep,
         if (!req->request.no_interrupt && !chain)
                 trb->ctrl |= DWC3_TRB_CTRL_IOC | DWC3_TRB_CTRL_ISP_IMI;
 
-        if (last)
+        if (last && !usb_endpoint_xfer_isoc(dep->endpoint.desc))
                 trb->ctrl |= DWC3_TRB_CTRL_LST;
 
         if (chain)
@@ -1955,7 +1955,8 @@ 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;
@@ -1964,17 +1965,22 @@ static int __dwc3_cleanup_done_trbs(struct dwc3 *dwc, struct dwc3_ep *dep,
         dep->queued_requests--;
         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
-                 * can do. If we don't clean it up we loop forever. If
-                 * we skip the TRB then it gets overwritten after a
-                 * while since we use them in a ring buffer. A BUG()
-                 * would help. Lets hope that if this occurs, someone
-                 * fixes the root cause instead of looking away :)
-                 */
-                dev_err(dwc->dev, "%s's TRB (%p) still owned by HW\n",
-                                dep->name, trb);
+                return 1;
+
         count = trb->size & DWC3_TRB_SIZE_MASK;
 
         if (dep->direction) {
@@ -2013,15 +2019,7 @@ 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 |
@@ -2040,13 +2038,17 @@ 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;
@@ -2054,13 +2056,22 @@ 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)