From 9e35ef73f7ea4813eea5531b4b8edc871cbc9e8d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jan=20D=C3=BCmpelmann?= <jan.duempelmann@inotec-licht.de>
Date: Tue, 30 Jun 2020 12:55:39 +0200
Subject: [PATCH] Fix receiving of short packet data (ep out)

---
 src/portable/st/synopsys/dcd_synopsys.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/portable/st/synopsys/dcd_synopsys.c b/src/portable/st/synopsys/dcd_synopsys.c
index b47101e60..0e8743ad8 100644
--- a/src/portable/st/synopsys/dcd_synopsys.c
+++ b/src/portable/st/synopsys/dcd_synopsys.c
@@ -576,6 +576,12 @@ static void handle_rxflvl_ints(USB_OTG_OUTEndpointTypeDef * out_ep) {
 
         // Increment pointer to xfer data
         xfer->buffer += bcnt;
+
+        // Truncate transfer length in case of short packet
+        if(bcnt < xfer->max_size){
+          xfer->total_len -= (out_ep[epnum].DOEPTSIZ & USB_OTG_DOEPTSIZ_XFRSIZ_Msk) >> USB_OTG_DOEPTSIZ_XFRSIZ_Pos;
+          if(epnum == 0) xfer->total_len -= ep0_pending[TUSB_DIR_OUT];
+        }
       }
       break;
     case 0x03: // Out packet done (Interrupt)