From patchwork Fri Jun 24 14:59:15 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Geert Uytterhoeven X-Patchwork-Id: 9197733 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id DF8E660871 for ; Fri, 24 Jun 2016 14:59:25 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id D0F89283E5 for ; Fri, 24 Jun 2016 14:59:25 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id C4661284B3; Fri, 24 Jun 2016 14:59:25 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 5D3A6283E5 for ; Fri, 24 Jun 2016 14:59:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751101AbcFXO7Y (ORCPT ); Fri, 24 Jun 2016 10:59:24 -0400 Received: from albert.telenet-ops.be ([195.130.137.90]:50659 "EHLO albert.telenet-ops.be" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751104AbcFXO7W (ORCPT ); Fri, 24 Jun 2016 10:59:22 -0400 Received: from ayla.of.borg ([84.195.107.21]) by albert.telenet-ops.be with bizsmtp id AezJ1t00C0TjorY06ezJDT; Fri, 24 Jun 2016 16:59:19 +0200 Received: from ramsan.of.borg ([192.168.97.29] helo=ramsan) by ayla.of.borg with esmtp (Exim 4.82) (envelope-from ) id 1bGSZi-0003Vv-6c; Fri, 24 Jun 2016 16:59:18 +0200 Received: from geert by ramsan with local (Exim 4.82) (envelope-from ) id 1bGSZj-0003IU-2w; Fri, 24 Jun 2016 16:59:19 +0200 From: Geert Uytterhoeven To: Greg Kroah-Hartman , Jiri Slaby Cc: Magnus Damm , Yoshihiro Shimoda , linux-serial@vger.kernel.org, linux-renesas-soc@vger.kernel.org, linux-sh@vger.kernel.org, uclinux-h8-devel@lists.sourceforge.jp, Geert Uytterhoeven Subject: [PATCH v2 3/4] serial: sh-sci: Clear RX, error, and break flags during reset Date: Fri, 24 Jun 2016 16:59:15 +0200 Message-Id: <1466780356-12623-4-git-send-email-geert+renesas@glider.be> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1466780356-12623-1-git-send-email-geert+renesas@glider.be> References: <1466780356-12623-1-git-send-email-geert+renesas@glider.be> Sender: linux-sh-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-sh@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Setting the FIFO reset bits is not sufficient to reset the RX FIFO. After this the status register's RDF flag bit may still be set, causing the reception of one stale byte of data. To fix this, clear all status flag bits related to reception, error, and break handling, cfr. the initialization flowchart in the datasheet. Signed-off-by: Geert Uytterhoeven --- v2: - No changes. --- drivers/tty/serial/sh-sci.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c index eecace576c3b758f..0a2be5d293220e08 100644 --- a/drivers/tty/serial/sh-sci.c +++ b/drivers/tty/serial/sh-sci.c @@ -2055,6 +2055,10 @@ static void sci_reset(struct uart_port *port) reg = sci_getreg(port, SCFCR); if (reg->size) serial_port_out(port, SCFCR, SCFCR_RFRST | SCFCR_TFRST); + + sci_clear_SCxSR(port, + SCxSR_RDxF_CLEAR(port) & SCxSR_ERROR_CLEAR(port) & + SCxSR_BREAK_CLEAR(port)); } static void sci_set_termios(struct uart_port *port, struct ktermios *termios,