From patchwork Thu Apr 7 12:31:07 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Valentin Caron X-Patchwork-Id: 558711 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 44DD2C433F5 for ; Thu, 7 Apr 2022 12:32:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245167AbiDGMeG (ORCPT ); Thu, 7 Apr 2022 08:34:06 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42850 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S245149AbiDGMeA (ORCPT ); Thu, 7 Apr 2022 08:34:00 -0400 Received: from mx07-00178001.pphosted.com (mx08-00178001.pphosted.com [91.207.212.93]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EEA25114090; Thu, 7 Apr 2022 05:32:00 -0700 (PDT) Received: from pps.filterd (m0046661.ppops.net [127.0.0.1]) by mx07-00178001.pphosted.com (8.16.1.2/8.16.1.2) with ESMTP id 237ApwOU022051; Thu, 7 Apr 2022 14:31:22 +0200 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=foss.st.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-type : content-transfer-encoding; s=selector1; bh=OzzsSeRZXTJPRZje9ui1T8+kROrim9zZTezfZrmqwVA=; b=RHV+xEWvG+cC0j9k6+66x8UD+84FpPc/RKoKwBCKJ2RUj/7ACDKSt2eZ2aHU13e6cgFh +xSihihv9nG3l19cDC7LJR7BPwC53f+ILSvmUWE5i3r7x5Ikck3WkZJzZeprXoFcOq3L DdHPalcKI5R1Vqcu4wBI1ILovAIUIiqke4z2pxOta0ihE+3veVw/OPYlu3+DKP1J9NUK E1mgymvNfnmQcqbY/BvcJZbmc0TpWqa4y7YEjTy0hMf6KMuEuLv4AXE3cJpu9ZxiwMh9 nlvh37p2nmwnOvDNSB0cun/LjSdpvgNrzena1G3I8yku7vMvVyK129qHzPkU/VDJBzzg ew== Received: from beta.dmz-eu.st.com (beta.dmz-eu.st.com [164.129.1.35]) by mx07-00178001.pphosted.com (PPS) with ESMTPS id 3f8x9gkwb6-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 07 Apr 2022 14:31:22 +0200 Received: from euls16034.sgp.st.com (euls16034.sgp.st.com [10.75.44.20]) by beta.dmz-eu.st.com (STMicroelectronics) with ESMTP id D74A4100034; Thu, 7 Apr 2022 14:31:21 +0200 (CEST) Received: from Webmail-eu.st.com (sfhdag2node2.st.com [10.75.127.5]) by euls16034.sgp.st.com (STMicroelectronics) with ESMTP id D005621A223; Thu, 7 Apr 2022 14:31:21 +0200 (CEST) Received: from localhost (10.75.127.49) by SFHDAG2NODE2.st.com (10.75.127.5) with Microsoft SMTP Server (TLS) id 15.0.1497.26; Thu, 7 Apr 2022 14:31:21 +0200 From: Valentin Caron To: Greg Kroah-Hartman , Jonathan Corbet CC: Jiri Slaby , Maxime Coquelin , Alexandre Torgue , Erwan Le Ray , Valentin Caron , , , , , Subject: [PATCH 1/3] serial: stm32: remove infinite loop possibility in putchar function Date: Thu, 7 Apr 2022 14:31:07 +0200 Message-ID: <20220407123109.132035-2-valentin.caron@foss.st.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20220407123109.132035-1-valentin.caron@foss.st.com> References: <20220407123109.132035-1-valentin.caron@foss.st.com> MIME-Version: 1.0 X-Originating-IP: [10.75.127.49] X-ClientProxiedBy: SFHDAG2NODE3.st.com (10.75.127.6) To SFHDAG2NODE2.st.com (10.75.127.5) X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.850,Hydra:6.0.425,FMLib:17.11.64.514 definitions=2022-04-07_01,2022-04-07_01,2022-02-23_01 Precedence: bulk List-ID: X-Mailing-List: linux-serial@vger.kernel.org Rework stm32_usart_console_putchar() function in order to anticipate the case where the character can never be sent. Signed-off-by: Valentin Caron --- drivers/tty/serial/stm32-usart.c | 12 +++++++++--- drivers/tty/serial/stm32-usart.h | 2 ++ 2 files changed, 11 insertions(+), 3 deletions(-) diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c index 87b5cd4c9743..83895da84891 100644 --- a/drivers/tty/serial/stm32-usart.c +++ b/drivers/tty/serial/stm32-usart.c @@ -1645,10 +1645,16 @@ static void stm32_usart_console_putchar(struct uart_port *port, unsigned char ch { struct stm32_port *stm32_port = to_stm32_port(port); const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; + u32 isr; + int ret; - while (!(readl_relaxed(port->membase + ofs->isr) & USART_SR_TXE)) - cpu_relax(); - + ret = readl_relaxed_poll_timeout_atomic(port->membase + ofs->isr, isr, + (isr & USART_SR_TXE), 100, + STM32_USART_TIMEOUT_USEC); + if (ret != 0) { + dev_err(port->dev, "Error while sending data in UART TX : %d\n", ret); + return; + } writel_relaxed(ch, port->membase + ofs->tdr); } diff --git a/drivers/tty/serial/stm32-usart.h b/drivers/tty/serial/stm32-usart.h index feab952aec16..d734c4a5fd24 100644 --- a/drivers/tty/serial/stm32-usart.h +++ b/drivers/tty/serial/stm32-usart.h @@ -251,6 +251,8 @@ struct stm32_usart_info stm32h7_info = { #define RX_BUF_P (RX_BUF_L / 2) /* dma rx buffer period */ #define TX_BUF_L RX_BUF_L /* dma tx buffer length */ +#define STM32_USART_TIMEOUT_USEC USEC_PER_SEC /* 1s timeout in µs */ + struct stm32_port { struct uart_port port; struct clk *clk;