From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755244AbdL1SMO (ORCPT ); Thu, 28 Dec 2017 13:12:14 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:58900 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754106AbdL1RNT (ORCPT ); Thu, 28 Dec 2017 12:13:19 -0500 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Felipe Balbi" , "Yoshihiro Shimoda" Date: Thu, 28 Dec 2017 16:59:12 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.2 29/94] usb: renesas_usbhs: fix usbhsf_fifo_clear() for RX direction In-Reply-To: X-SA-Exim-Connect-IP: 2a02:8011:400e:2:6f00:88c8:c921:d332 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.2.97-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Yoshihiro Shimoda commit 0a2ce62b61f2c76d0213edf4e37aaf54a8ddf295 upstream. This patch fixes an issue that the usbhsf_fifo_clear() is possible to cause 10 msec delay if the pipe is RX direction and empty because the FRDY bit will never be set to 1 in such case. Fixes: e8d548d54968 ("usb: renesas_usbhs: fifo became independent from pipe.") Signed-off-by: Yoshihiro Shimoda Signed-off-by: Felipe Balbi Signed-off-by: Ben Hutchings --- drivers/usb/renesas_usbhs/fifo.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) --- a/drivers/usb/renesas_usbhs/fifo.c +++ b/drivers/usb/renesas_usbhs/fifo.c @@ -263,8 +263,17 @@ static void usbhsf_fifo_clear(struct usb struct usbhs_priv *priv = usbhs_pipe_to_priv(pipe); int ret = 0; - if (!usbhs_pipe_is_dcp(pipe)) - ret = usbhsf_fifo_barrier(priv, fifo); + if (!usbhs_pipe_is_dcp(pipe)) { + /* + * This driver checks the pipe condition first to avoid -EBUSY + * from usbhsf_fifo_barrier() with about 10 msec delay in + * the interrupt handler if the pipe is RX direction and empty. + */ + if (usbhs_pipe_is_dir_in(pipe)) + ret = usbhs_pipe_is_accessible(pipe); + if (!ret) + ret = usbhsf_fifo_barrier(priv, fifo); + } /* * if non-DCP pipe, this driver should set BCLR when