From patchwork Thu May 20 09:21:27 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 444148 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=-19.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, 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 026FCC43461 for ; Thu, 20 May 2021 10:53:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D9A44610CB for ; Thu, 20 May 2021 10:53:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238506AbhETKzL (ORCPT ); Thu, 20 May 2021 06:55:11 -0400 Received: from mail.kernel.org ([198.145.29.99]:52618 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239158AbhETKwW (ORCPT ); Thu, 20 May 2021 06:52:22 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id BD32F61CD4; Thu, 20 May 2021 10:00:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1621504820; bh=k9hY5c6WXJ7Q1V86HdSxEhH1qKwJI1abMbTBwNS3TC4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=iU16lp6V2frHut2ub+v1IZ3y2IzDxaV6UJOpNMBEFav1QHLN8Osf/yXIbaLHTISvO VLcALIuk7ulEKSkUntclFIzdKyHTkHEk7X0Ot1TdHM7aGjOJ97sqTzwv7TadJIpn3k PavYFelZfc6rDovwIzWplsfVFlMU+GawdnDRYi0g= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Erwan Le Ray , Sasha Levin Subject: [PATCH 4.9 095/240] serial: stm32: fix incorrect characters on console Date: Thu, 20 May 2021 11:21:27 +0200 Message-Id: <20210520092111.881449775@linuxfoundation.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210520092108.587553970@linuxfoundation.org> References: <20210520092108.587553970@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Erwan Le Ray [ Upstream commit f264c6f6aece81a9f8fbdf912b20bd3feb476a7a ] Incorrect characters are observed on console during boot. This issue occurs when init/main.c is modifying termios settings to open /dev/console on the rootfs. This patch adds a waiting loop in set_termios to wait for TX shift register empty (and TX FIFO if any) before stopping serial port. Fixes: 48a6092fb41f ("serial: stm32-usart: Add STM32 USART Driver") Signed-off-by: Erwan Le Ray Link: https://lore.kernel.org/r/20210304162308.8984-4-erwan.leray@foss.st.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- drivers/tty/serial/stm32-usart.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c index ea8b591dd46f..f325019887b2 100644 --- a/drivers/tty/serial/stm32-usart.c +++ b/drivers/tty/serial/stm32-usart.c @@ -476,8 +476,9 @@ static void stm32_set_termios(struct uart_port *port, struct ktermios *termios, unsigned int baud; u32 usartdiv, mantissa, fraction, oversampling; tcflag_t cflag = termios->c_cflag; - u32 cr1, cr2, cr3; + u32 cr1, cr2, cr3, isr; unsigned long flags; + int ret; if (!stm32_port->hw_flow_control) cflag &= ~CRTSCTS; @@ -486,6 +487,15 @@ static void stm32_set_termios(struct uart_port *port, struct ktermios *termios, spin_lock_irqsave(&port->lock, flags); + ret = readl_relaxed_poll_timeout_atomic(port->membase + ofs->isr, + isr, + (isr & USART_SR_TC), + 10, 100000); + + /* Send the TC error message only when ISR_TC is not set. */ + if (ret) + dev_err(port->dev, "Transmission is not complete\n"); + /* Stop serial port and reset value */ writel_relaxed(0, port->membase + ofs->cr1);