From 7770aae80579ec801685b0f37c2077c9c7b559bb Mon Sep 17 00:00:00 2001
From: Sasha Levin <sashal@kernel.org>
Date: Wed, 24 Mar 2021 15:11:15 +0100
Subject: fotg210-udc: Complete OUT requests on short packets

From: Fabian Vogt <fabian@ritter-vogt.de>

[ Upstream commit 75bb93be0027123b5db6cbcce89eb62f0f6b3c5b ]

A short packet indicates the end of a transfer and marks the request as
complete.

Fixes: b84a8dee23fd ("usb: gadget: add Faraday fotg210_udc driver")
Signed-off-by: Fabian Vogt <fabian@ritter-vogt.de>
Link: https://lore.kernel.org/r/20210324141115.9384-8-fabian@ritter-vogt.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/usb/gadget/udc/fotg210-udc.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/gadget/udc/fotg210-udc.c b/drivers/usb/gadget/udc/fotg210-udc.c
index 9925d7ac9138..75bf446f4a66 100644
--- a/drivers/usb/gadget/udc/fotg210-udc.c
+++ b/drivers/usb/gadget/udc/fotg210-udc.c
@@ -849,12 +849,16 @@ static void fotg210_out_fifo_handler(struct fotg210_ep *ep)
 {
 	struct fotg210_request *req = list_entry(ep->queue.next,
 						 struct fotg210_request, queue);
+	int disgr1 = ioread32(ep->fotg210->reg + FOTG210_DISGR1);
 
 	fotg210_start_dma(ep, req);
 
-	/* finish out transfer */
+	/* Complete the request when it's full or a short packet arrived.
+	 * Like other drivers, short_not_ok isn't handled.
+	 */
+
 	if (req->req.length == req->req.actual ||
-	    req->req.actual < ep->ep.maxpacket)
+	    (disgr1 & DISGR1_SPK_INT(ep->epnum - 1)))
 		fotg210_done(ep, req, 0);
 }
 
-- 
2.30.2