From patchwork Wed May 12 14:43:35 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 438043 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=-19.4 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 EF78BC2BA02 for ; Wed, 12 May 2021 16:37:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D757160BBB for ; Wed, 12 May 2021 16:37:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234750AbhELQiC (ORCPT ); Wed, 12 May 2021 12:38:02 -0400 Received: from mail.kernel.org ([198.145.29.99]:43950 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234629AbhELQ2a (ORCPT ); Wed, 12 May 2021 12:28:30 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 914A6613BD; Wed, 12 May 2021 15:56:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1620835003; bh=PLTfKQw5caY+K+Rp6UJM0SZ9Aq8X6/mhXXIH7X1cZWI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=bSicpLb1wEd7YraZpDTUSZT+In+1aiNADGlYeEqTuN/8z3O7vdn3Lo3VKlspPo3LR PA5L9waKKoDtbW7ZAaFPYplrO+X0rO/8L1ii05/Ygy+geR3zhau3XvfneCntfXA4dG FTw042+dCF7WqV1f4EzIXQ27AHxiGEcLIVKw4lmA= 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 5.12 169/677] serial: stm32: fix FIFO flush in startup and set_termios Date: Wed, 12 May 2021 16:43:35 +0200 Message-Id: <20210512144842.856817557@linuxfoundation.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210512144837.204217980@linuxfoundation.org> References: <20210512144837.204217980@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 315e2d8a125ad77a1bc28f621162713f3e7aef48 ] Fifo flush set USART_RQR register by calling stm32_usart_set_bits routine (Read/Modify/Write). USART_RQR register is a write only register. So, read before write isn't correct / relevant to flush the FIFOs. Replace stm32_usart_set_bits call by writel_relaxed. Fixes: 84872dc448fe ("serial: stm32: add RX and TX FIFO flush") Signed-off-by: Erwan Le Ray Link: https://lore.kernel.org/r/20210304162308.8984-11-erwan.leray@foss.st.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- drivers/tty/serial/stm32-usart.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c index 2bdd04a47f91..183c76ddb165 100644 --- a/drivers/tty/serial/stm32-usart.c +++ b/drivers/tty/serial/stm32-usart.c @@ -657,7 +657,7 @@ static int stm32_usart_startup(struct uart_port *port) /* RX FIFO Flush */ if (ofs->rqr != UNDEF_REG) - stm32_usart_set_bits(port, ofs->rqr, USART_RQR_RXFRQ); + writel_relaxed(USART_RQR_RXFRQ, port->membase + ofs->rqr); /* RX enabling */ val = stm32_port->cr1_irq | USART_CR1_RE | BIT(cfg->uart_enable_bit); @@ -762,8 +762,8 @@ static void stm32_usart_set_termios(struct uart_port *port, /* flush RX & TX FIFO */ if (ofs->rqr != UNDEF_REG) - stm32_usart_set_bits(port, ofs->rqr, - USART_RQR_TXFRQ | USART_RQR_RXFRQ); + writel_relaxed(USART_RQR_TXFRQ | USART_RQR_RXFRQ, + port->membase + ofs->rqr); cr1 = USART_CR1_TE | USART_CR1_RE; if (stm32_port->fifoen)