usb: gadget: dummy_hcd: emulate sending zlp in packet logic

currently, when a zlp flag is set and an urb/usb_request
buffer is filled without a short packet, transfer() leaves
its status at -EINPROGRESS and does not rescan for short
packet.

In a scenario where ep.maxpacket bytes are copied,
URB_ZERO_PACKET is set, urb buffer is filled and usb_request
buffer is not, transfer() returns with an urb with
-EINPROGRESS status, which dummy_hcd treats as incomplete
transfer.

Check for zlp and rescan appropriately.

Signed-off-by: Igor Kotrasinski <i.kotrasinsk@samsung.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

diff --git a/drivers/usb/gadget/udc/dummy_hcd.c b/drivers/usb/gadget/udc/dummy_hcd.c
index 1379ad40d864bd42308f0c336fe931e8c757355e..93b38f88e7b2c8fad9e3bcfc20c53bd02979d621 100644 (file)
--- a/drivers/usb/gadget/udc/dummy_hcd.c
+++ b/drivers/usb/gadget/udc/dummy_hcd.c
@@ -1429,15 +1429,24 @@ top:
                                        req->req.status = 0;
                        }
 
-               /* many requests terminate without a short packet */
+               /*
+                * many requests terminate without a short packet.
+                * send a zlp if demanded by flags.
+                */
                } else {
-                       if (req->req.length == req->req.actual
-                                       && !req->req.zero)
-                               req->req.status = 0;
-                       if (urb->transfer_buffer_length == urb->actual_length
-                                       && !(urb->transfer_flags
-                                               & URB_ZERO_PACKET))
-                               *status = 0;
+                       if (req->req.length == req->req.actual) {
+                               if (req->req.zero && to_host)
+                                       rescan = 1;
+                               else
+                                       req->req.status = 0;
+                       }
+                       if (urb->transfer_buffer_length == urb->actual_length) {
+                               if (urb->transfer_flags & URB_ZERO_PACKET &&
+                                   !to_host)
+                                       rescan = 1;
+                               else
+                                       *status = 0;
+                       }
                }
 
                /* device side completion --> continuable */