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=unavailable 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 F25FAC10F05 for ; Mon, 1 Apr 2019 17:54:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B9CDA2084B for ; Mon, 1 Apr 2019 17:54:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1554141265; bh=En+o/ldLhCWof7UhYPdSGpUcozkzYCe+LMDy/q52jH4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=Tf5wJn7Y+7dxY0dEFYUsj4gCEHkc348r4zQRhFfRnYdbAtnPZ6r/5oJwLyQ+9KvNi x2BFJkzGLh6Ctf3JOavxHHF6jBFI2ryLdblJG9J1eHZWBFriaC98xnzlpon59KFwMD VA25BF8Z5nIZZNjl8bYeHpPgfX6Dd/IEEeDp39kY= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731497AbfDARYm (ORCPT ); Mon, 1 Apr 2019 13:24:42 -0400 Received: from mail.kernel.org ([198.145.29.99]:55416 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731282AbfDARYl (ORCPT ); Mon, 1 Apr 2019 13:24:41 -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 932EC2063F; Mon, 1 Apr 2019 17:24:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1554139481; bh=En+o/ldLhCWof7UhYPdSGpUcozkzYCe+LMDy/q52jH4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=hERALvVn1UqWDlpG0RHN2xFUg+2xTYmM45SFSIvvSInRQJDRquhSwA8RYoYr+tBYR cxy4rJrKxP96tOtyjDedA5kPp4zEpwbEOf1NoYBoHBdverN5+N82Gnj7nZCUZnr0GW ONutC43I1X4B3FMqaN9ZHSupVpjOt8aD4xOjXUZU= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Hoan Nguyen An Subject: [PATCH 4.14 081/107] serial: sh-sci: Fix setting SCSCR_TIE while transferring data Date: Mon, 1 Apr 2019 19:02:36 +0200 Message-Id: <20190401170052.999982066@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190401170045.246405031@linuxfoundation.org> References: <20190401170045.246405031@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: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org 4.14-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 @@ -806,19 +806,9 @@ 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 */