From patchwork Wed May 12 14:43:28 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 436478 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 6B19DC2B9FE 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 4E22660BBB for ; Wed, 12 May 2021 16:37:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236394AbhELQhw (ORCPT ); Wed, 12 May 2021 12:37:52 -0400 Received: from mail.kernel.org ([198.145.29.99]:44582 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233893AbhELQ2F (ORCPT ); Wed, 12 May 2021 12:28:05 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 281D2613D3; Wed, 12 May 2021 15:56:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1620834981; bh=lk9tu94Lwm8/riKxHRlcd/USiVXjtwmDE+xZTkh7tkg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=EPsKu8yHhAf2gv8RPMadIDsU7xz4KCZxofbEbaXYPyiCe8noEREySPwTqtzbntd08 RjC4BdyBcLzvogMVdo1abDUz3dj1fax47SNKp16C4D7kNfn/Jx1YfXThxBr2i8z/eS rE9SaiJLnL4Y2NwwF53StkZ/SN66yETt2TRWnTF4= 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 5.12 162/677] serial: stm32: fix TX and RX FIFO thresholds Date: Wed, 12 May 2021 16:43:28 +0200 Message-Id: <20210512144842.631267364@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 25a8e7611da5513b388165661b17173c26e12c04 ] TX and RX FIFO thresholds may be cleared after suspend/resume, depending on the low power mode. Those configurations (done in startup) are not effective for UART console, as: - the reference manual indicates that FIFOEN bit can only be written when the USART is disabled (UE=0) - a set_termios (where UE is set) is requested firstly for console enabling, before the startup. Fixes: 84872dc448fe ("serial: stm32: add RX and TX FIFO flush") Signed-off-by: Erwan Le Ray Link: https://lore.kernel.org/r/20210304162308.8984-5-erwan.leray@foss.st.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- drivers/tty/serial/stm32-usart.c | 23 +++++++++-------------- 1 file changed, 9 insertions(+), 14 deletions(-) diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c index eae54b8cf5e2..223cec70c57c 100644 --- a/drivers/tty/serial/stm32-usart.c +++ b/drivers/tty/serial/stm32-usart.c @@ -649,19 +649,8 @@ static int stm32_usart_startup(struct uart_port *port) if (ofs->rqr != UNDEF_REG) stm32_usart_set_bits(port, ofs->rqr, USART_RQR_RXFRQ); - /* Tx and RX FIFO configuration */ - if (stm32_port->fifoen) { - val = readl_relaxed(port->membase + ofs->cr3); - val &= ~(USART_CR3_TXFTCFG_MASK | USART_CR3_RXFTCFG_MASK); - val |= USART_CR3_TXFTCFG_HALF << USART_CR3_TXFTCFG_SHIFT; - val |= USART_CR3_RXFTCFG_HALF << USART_CR3_RXFTCFG_SHIFT; - writel_relaxed(val, port->membase + ofs->cr3); - } - - /* RX FIFO enabling */ + /* RX enabling */ val = stm32_port->cr1_irq | USART_CR1_RE | BIT(cfg->uart_enable_bit); - if (stm32_port->fifoen) - val |= USART_CR1_FIFOEN; stm32_usart_set_bits(port, ofs->cr1, val); return 0; @@ -770,9 +759,15 @@ static void stm32_usart_set_termios(struct uart_port *port, if (stm32_port->fifoen) cr1 |= USART_CR1_FIFOEN; cr2 = 0; + + /* Tx and RX FIFO configuration */ cr3 = readl_relaxed(port->membase + ofs->cr3); - cr3 &= USART_CR3_TXFTIE | USART_CR3_RXFTCFG_MASK | USART_CR3_RXFTIE - | USART_CR3_TXFTCFG_MASK; + cr3 &= USART_CR3_TXFTIE | USART_CR3_RXFTIE; + if (stm32_port->fifoen) { + cr3 &= ~(USART_CR3_TXFTCFG_MASK | USART_CR3_RXFTCFG_MASK); + cr3 |= USART_CR3_TXFTCFG_HALF << USART_CR3_TXFTCFG_SHIFT; + cr3 |= USART_CR3_RXFTCFG_HALF << USART_CR3_RXFTCFG_SHIFT; + } if (cflag & CSTOPB) cr2 |= USART_CR2_STOP_2B;