fotg210-udc: Fix DMA on EP0 for length > max packet size

[ Upstream commit 755915fc28edfc608fa89a163014acb2f31c1e19 ]

For a 75 Byte request, it would send the first 64 separately, then detect
that the remaining 11 Byte fit into a single DMA, but due to this bug set
the length to the original 75 Bytes. This leads to a DMA failure (which is
ignored...) and the request completes without the remaining bytes having
been sent.

Fixes: b84a8dee23fd ("usb: gadget: add Faraday fotg210_udc driver")
Signed-off-by: Fabian Vogt <fabian@ritter-vogt.de>
Link: https://lore.kernel.org/r/20210324141115.9384-2-fabian@ritter-vogt.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/usb/gadget/udc/fotg210-udc.c b/drivers/usb/gadget/udc/fotg210-udc.c
index 76e991557116ab1012186c363e78f4e25add02d8..7831c556a40bb447f5fd46ff038417c6854c11f6 100644 (file)
--- a/drivers/usb/gadget/udc/fotg210-udc.c
+++ b/drivers/usb/gadget/udc/fotg210-udc.c
@@ -348,7 +348,7 @@ static void fotg210_start_dma(struct fotg210_ep *ep,
                if (req->req.length - req->req.actual > ep->ep.maxpacket)
                        length = ep->ep.maxpacket;
                else
-                       length = req->req.length;
+                       length = req->req.length - req->req.actual;
        }
 
        d = dma_map_single(NULL, buffer, length,