From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 727AEC43381 for ; Mon, 1 Apr 2019 17:35:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 42CEB20896 for ; Mon, 1 Apr 2019 17:35:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1554140141; bh=b8WM7whjftxy9t4I7BYkPHZthKRQE+gn+bqewVPXn6g=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=nk5xfG/7ZIkrpFKgGcmRbWbwxqsdTY5t+wH0auexnH9xmIhD5K5MPnJsvV41fFZw3 0a1gPxZSNweQNhmQ8LMUy7wQmaqmY18w5E+f8DwrY+XT8sJGMLYU0Q2kaT6VaMIK0u rLaaCXZz39Yaz2+vzUEvpXeozYtRPtfh+WuEFDWg= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387939AbfDARfj (ORCPT ); Mon, 1 Apr 2019 13:35:39 -0400 Received: from mail.kernel.org ([198.145.29.99]:46526 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387541AbfDARfh (ORCPT ); Mon, 1 Apr 2019 13:35:37 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id CB9ED20880; Mon, 1 Apr 2019 17:35:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1554140136; bh=b8WM7whjftxy9t4I7BYkPHZthKRQE+gn+bqewVPXn6g=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=fRK/q1qR92NcfblMHH6apmsohvOzCheFTIch9VrYniDBG06LbMyr8pjDQe3jI5JOH kG6Cza3VVTFCYp++H/6OcJtejXCEAIonxz1yMAIW2hFvGxYM87D+WBNmf9ZsuF8i6x u32f793ew/yjV0jyIS88VI8MIUJKkRiVnkKXIzaU= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Hoan Nguyen An Subject: [PATCH 4.4 115/131] serial: sh-sci: Fix setting SCSCR_TIE while transferring data Date: Mon, 1 Apr 2019 19:03:05 +0200 Message-Id: <20190401170101.266887323@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190401170051.645954551@linuxfoundation.org> References: <20190401170051.645954551@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Hoan Nguyen An commit 93bcefd4c6bad4c69dbc4edcd3fbf774b24d930d upstream. We disable transmission interrupt (clear SCSCR_TIE) after all data has been transmitted (if uart_circ_empty(xmit)). While transmitting, if the data is still in the tty buffer, re-enable the SCSCR_TIE bit, which was done at sci_start_tx(). This is unnecessary processing, wasting CPU operation if the data transmission length is large. And further, transmit end, FIFO empty bits disabling have also been performed in the step above. Signed-off-by: Hoan Nguyen An Cc: stable Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/sh-sci.c | 12 +----------- 1 file changed, 1 insertion(+), 11 deletions(-) --- a/drivers/tty/serial/sh-sci.c +++ b/drivers/tty/serial/sh-sci.c @@ -746,19 +746,9 @@ static void sci_transmit_chars(struct ua if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) uart_write_wakeup(port); - if (uart_circ_empty(xmit)) { + if (uart_circ_empty(xmit)) sci_stop_tx(port); - } else { - ctrl = serial_port_in(port, SCSCR); - if (port->type != PORT_SCI) { - serial_port_in(port, SCxSR); /* Dummy read */ - sci_clear_SCxSR(port, SCxSR_TDxE_CLEAR(port)); - } - - ctrl |= SCSCR_TIE; - serial_port_out(port, SCSCR, ctrl); - } } /* On SH3, SCIF may read end-of-break as a space->mark char */