[PATCH 3/3] usb: gadget: udc: renesas_usb3: Fix return value of usb3_write_pipe()

[Yoshihiro Shimoda]

This patch fixes an issue that this driver cannot go status stage
in control read when the req.zero is set to 1 and the len in
usb3_write_pipe() is set to 0. Otherwise, if we use g_ncm driver,
usb enumeration takes long time (5 seconds or more).

Fixes: 746bfe63bba3 ("usb: gadget: renesas_usb3: add support for Renesas USB3.0 
peripheral controller")
Cc: <sta...@vger.kernel.org> # v4.5+
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda...@renesas.com>
---
 drivers/usb/gadget/udc/renesas_usb3.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/gadget/udc/renesas_usb3.c 
b/drivers/usb/gadget/udc/renesas_usb3.c
index 7e0c534..63a2061 100644
--- a/drivers/usb/gadget/udc/renesas_usb3.c
+++ b/drivers/usb/gadget/udc/renesas_usb3.c
@@ -1038,7 +1038,7 @@ static int usb3_write_pipe(struct renesas_usb3_ep 
*usb3_ep,
                        usb3_ep->ep.maxpacket);
        u8 *buf = usb3_req->req.buf + usb3_req->req.actual;
        u32 tmp = 0;
-       bool is_last;
+       bool is_last = !len ? true : false;
 
        if (usb3_wait_pipe_status(usb3_ep, PX_STA_BUFSTS) < 0)
                return -EBUSY;
@@ -1059,7 +1059,8 @@ static int usb3_write_pipe(struct renesas_usb3_ep 
*usb3_ep,
                usb3_write(usb3, tmp, fifo_reg);
        }
 
-       is_last = usb3_is_transfer_complete(usb3_ep, usb3_req);
+       if (!is_last)
+               is_last = usb3_is_transfer_complete(usb3_ep, usb3_req);
        /* Send the data */
        usb3_set_px_con_send(usb3_ep, len, is_last);
 
-- 
1.9.1