usb: renesas_usbhs: gadget: Fix usb_ep_set_{halt,wedge}() behavior

According to usb_ep_set_halt()'s description,
__usbhsg_ep_set_halt_wedge() should return -EAGAIN if the IN endpoint
has any queue or data. Otherwise, this driver is possible to cause
just STALL without sending a short packet data on g_mass_storage driver,
and then a few resetting a device happens on a host side during
a usb enumaration.

Fixes: 2f98382dcdfe ("usb: renesas_usbhs: Add Renesas USBHS Gadget")
Cc: <stable@vger.kernel.org> # v3.0+
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Link: https://lore.kernel.org/r/1569924633-322-3-git-send-email-yoshihiro.shimoda.uh@renesas.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/usb/renesas_usbhs/mod_gadget.c b/drivers/usb/renesas_usbhs/mod_gadget.c
index 2c7523a..e5ef569 100644
--- a/drivers/usb/renesas_usbhs/mod_gadget.c
+++ b/drivers/usb/renesas_usbhs/mod_gadget.c
@@ -722,6 +722,7 @@ static int __usbhsg_ep_set_halt_wedge(struct usb_ep *ep, int halt, int wedge)
 	struct usbhs_priv *priv = usbhsg_gpriv_to_priv(gpriv);
 	struct device *dev = usbhsg_gpriv_to_dev(gpriv);
 	unsigned long flags;
+	int ret = 0;
 
 	dev_dbg(dev, "set halt %d (pipe %d)\n",
 		halt, usbhs_pipe_number(pipe));
@@ -729,6 +730,18 @@ static int __usbhsg_ep_set_halt_wedge(struct usb_ep *ep, int halt, int wedge)
 	/********************  spin lock ********************/
 	usbhs_lock(priv, flags);
 
+	/*
+	 * According to usb_ep_set_halt()'s description, this function should
+	 * return -EAGAIN if the IN endpoint has any queue or data. Note
+	 * that the usbhs_pipe_is_dir_in() returns false if the pipe is an
+	 * IN endpoint in the gadget mode.
+	 */
+	if (!usbhs_pipe_is_dir_in(pipe) && (__usbhsf_pkt_get(pipe) ||
+	    usbhs_pipe_contains_transmittable_data(pipe))) {
+		ret = -EAGAIN;
+		goto out;
+	}
+
 	if (halt)
 		usbhs_pipe_stall(pipe);
 	else
@@ -739,10 +752,11 @@ static int __usbhsg_ep_set_halt_wedge(struct usb_ep *ep, int halt, int wedge)
 	else
 		usbhsg_status_clr(gpriv, USBHSG_STATUS_WEDGE);
 
+out:
 	usbhs_unlock(priv, flags);
 	/********************  spin unlock ******************/
 
-	return 0;
+	return ret;
 }
 
 static int usbhsg_ep_set_halt(struct usb_ep *ep, int value)