1 files changed, 32 insertions, 5 deletions

diff --git a/drivers/usb/dwc3/ep0.c b/drivers/usb/dwc3/ep0.c
index a6fc5c316743..f1e0a5eb0544 100644
--- a/drivers/usb/dwc3/ep0.c
+++ b/drivers/usb/dwc3/ep0.c
@@ -185,10 +185,29 @@ static int __dwc3_gadget_ep0_queue(struct dwc3_ep *dep,
         req->epnum              = dep->number;
 
         list_add_tail(&req->list, &dep->request_list);
-        dwc3_map_buffer_to_dma(req);
+        if (req->request.length == 0) {
+                ret = dwc3_ep0_start_trans(dwc, dep->number,
+                                dwc->ctrl_req_addr, 0);
+        } else if ((req->request.length % dep->endpoint.maxpacket)
+                        && (dep->number == 0)) {
+                dwc->ep0_bounced = true;
+
+                WARN_ON(req->request.length > dep->endpoint.maxpacket);
+
+                /*
+                 * REVISIT in case request length is bigger than EP0
+                 * wMaxPacketSize, we will need two chained TRBs to handle
+                 * the transfer.
+                 */
+                ret = dwc3_ep0_start_trans(dwc, dep->number,
+                                dwc->ep0_bounce_addr, dep->endpoint.maxpacket);
+        } else {
+                dwc3_map_buffer_to_dma(req);
+
+                ret = dwc3_ep0_start_trans(dwc, dep->number,
+                                req->request.dma, req->request.length);
+        }
 
-        ret = dwc3_ep0_start_trans(dwc, dep->number, req->request.dma,
-                        req->request.length);
         if (ret < 0) {
                 list_del(&req->list);
                 dwc3_unmap_buffer_from_dma(req);
@@ -655,8 +674,16 @@ static void dwc3_ep0_complete_data(struct dwc3 *dwc,
 
         dwc3_trb_to_nat(dwc->ep0_trb, &trb);
 
-        transferred = ur->length - trb.length;
-        ur->actual += transferred;
+        if (dwc->ep0_bounced) {
+                struct dwc3_ep  *ep0 = dwc->eps[0];
+
+                transferred = min(ur->length, dep->endpoint.maxpacket - trb.length);
+                memcpy(ur->buf, dwc->ep0_bounce, transferred);
+                dwc->ep0_bounced = false;
+        } else {
+                transferred = ur->length - trb.length;
+                ur->actual += transferred;
+        }
 
         if ((epnum & 1) && ur->actual < ur->length) {
                 /* for some reason we did not get everything out */