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=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,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 BD702C43603 for ; Wed, 4 Dec 2019 18:11:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9081720863 for ; Wed, 4 Dec 2019 18:11:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1575483104; bh=d0ntVbZyiTVQFUBkfKqRFVdd7wKYeRXw4kRDxXAxktk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=pL4AHayrRmyCrUVfnIWlcv05soh4rjV78zc7uBHSwzP7F6dxRAd4MjZWaekSK92G2 aWtpEfuqTH1Idk6ROt3m7y9HGkpi5mZx1S5FmqCjfdd4XN1ZdB5yJ13EZOc4XFQeOa buOfqjLFZt0yJdoVh0obB6ypInuDmrNGCSDcCrCw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731507AbfLDSLn (ORCPT ); Wed, 4 Dec 2019 13:11:43 -0500 Received: from mail.kernel.org ([198.145.29.99]:39998 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731490AbfLDSLl (ORCPT ); Wed, 4 Dec 2019 13:11:41 -0500 Received: from localhost (unknown [217.68.49.72]) (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 D7D8720674; Wed, 4 Dec 2019 18:11:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1575483101; bh=d0ntVbZyiTVQFUBkfKqRFVdd7wKYeRXw4kRDxXAxktk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ncGieG/yWyrGcUjQkJHNsVvH5hn+hZckYtp3qFrOtScLEJ9lzK6MzqBsXm0I7uP7b fJP+jhoBZvlad9mMsx1N83Gvfcr0whMtwD5IZ/aY6BMzn+1yvRvihBs+w1nHuCjAKX Qp97HMDc3BRxccg1I4qK9QQ1ZM50qYt7ZMU5cank= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Alexander Shiyan , Sasha Levin Subject: [PATCH 4.9 053/125] serial: max310x: Fix tx_empty() callback Date: Wed, 4 Dec 2019 18:55:58 +0100 Message-Id: <20191204175322.212044612@linuxfoundation.org> X-Mailer: git-send-email 2.24.0 In-Reply-To: <20191204175308.377746305@linuxfoundation.org> References: <20191204175308.377746305@linuxfoundation.org> User-Agent: quilt/0.66 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 From: Alexander Shiyan [ Upstream commit a8da3c7873ea57acb8f9cea58c0af477522965aa ] Function max310x_tx_empty() accesses the IRQSTS register, which is cleared by IC when reading, so if there is an interrupt status, we will lose it. This patch implement the transmitter check only by the current FIFO level. Signed-off-by: Alexander Shiyan Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- drivers/tty/serial/max310x.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-) diff --git a/drivers/tty/serial/max310x.c b/drivers/tty/serial/max310x.c index bacc7e284c0c1..80ab672d61cc4 100644 --- a/drivers/tty/serial/max310x.c +++ b/drivers/tty/serial/max310x.c @@ -769,12 +769,9 @@ static void max310x_start_tx(struct uart_port *port) static unsigned int max310x_tx_empty(struct uart_port *port) { - unsigned int lvl, sts; + u8 lvl = max310x_port_read(port, MAX310X_TXFIFOLVL_REG); - lvl = max310x_port_read(port, MAX310X_TXFIFOLVL_REG); - sts = max310x_port_read(port, MAX310X_IRQSTS_REG); - - return ((sts & MAX310X_IRQ_TXEMPTY_BIT) && !lvl) ? TIOCSER_TEMT : 0; + return lvl ? 0 : TIOCSER_TEMT; } static unsigned int max310x_get_mctrl(struct uart_port *port) -- 2.20.1