From patchwork Fri Apr 5 09:25:13 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Esben Haabendal X-Patchwork-Id: 13618770 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 97CDBCD11C2 for ; Fri, 5 Apr 2024 09:25:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:Message-ID:Date:Subject:Cc :To:From:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References: List-Owner; bh=GKKaPdnNinHo+OaiGZEnVfGtB1pYKin+bU+WuVjH4UM=; b=xrrIVd1DjIQ0aT oBW9bXZqykAt+aPuKkT82Pf0WMbzVU3ca12/8pi+X/y8MmMr9XgtuWw8wdwIO2llBm2mnDFV7Udrm 4TsuPv8C4s5/ZBlomq7uF8ZlMLM5VRU1IkVWUjqjRTK5w5idpkDSvJ7FUtQmks7qbsg3/uBf7YGVn PgY0mMphSXOqR5O8Ycft7ImulGa4F50wUsV7JZdlBjNELePbsrQH76rSxSHpLLgM9Woy3xRs2AYhE ydpRe48xrcIIKIwHJtPDUvb60HgEOsgckLJ8Cxgg8JghmOg9SeGF6WEMoNFiHcIqCQRWK9PwqTLZ5 WDw2u/Gs7WGW0fn9Oj9g==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1rsfp7-00000006Awl-3HUt; Fri, 05 Apr 2024 09:25:25 +0000 Received: from www530.your-server.de ([188.40.30.78]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1rsfp4-00000006Aul-1IAu for linux-arm-kernel@lists.infradead.org; Fri, 05 Apr 2024 09:25:23 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=geanix.com; s=default2211; h=Content-Transfer-Encoding:MIME-Version:Message-ID:Date: Subject:Cc:To:From:Sender:Reply-To:Content-Type:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:In-Reply-To:References; bh=7dcSbryEJQBvrS2PQ/uX0RZsRPEyzPJFXC461YQLAEI=; b=WcMRfZrHfD5Kz+BAUns9apNjZy N/6W5kSGc9CvCl/0AgBAZA/Qja5Dc3ZAtnJ074m1/gIW+V0M7YiVtMu4YJ75IcQR8NXQVd48BJ4cX yjcwcc4dvsGy7p2TAlFKkKyBCTEtENxVPHxSyulOIeD5fUD5baGCo1X6PycvDbNex3wnUoeXyX567 WsbKAhCSvBi5O4Eu9N/LqmavJcScDcU8XWDBRrErZW4tR1BlDHMUWai/KFADXLr0xhwGsbAH1YYJn 2FZ7PId0xWVCH33V8AWPAwnderJESA6czDKtukDaWAvz3fyAhGSjbDz1abBmrHsC5nrm+Zsy/ZxeV my/os/ew==; Received: from sslproxy04.your-server.de ([78.46.152.42]) by www530.your-server.de with esmtpsa (TLS1.3) tls TLS_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1rsfow-000KBi-TR; Fri, 05 Apr 2024 11:25:14 +0200 Received: from [185.17.218.86] (helo=localhost) by sslproxy04.your-server.de with esmtpsa (TLS1.3) tls TLS_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1rsfow-000AR5-0H; Fri, 05 Apr 2024 11:25:14 +0200 From: Esben Haabendal To: Greg Kroah-Hartman , Jiri Slaby , Shawn Guo , Sascha Hauer , Pengutronix Kernel Team , Fabio Estevam Cc: Marc Kleine-Budde , linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org, imx@lists.linux.dev, linux-arm-kernel@lists.infradead.org Subject: [PATCH 1/2] serial: imx: Introduce timeout when waiting on transmitter empty Date: Fri, 5 Apr 2024 11:25:13 +0200 Message-ID: <76cf9ce9cbf9dcdf78bc00ce7a919db1776ebce1.1712309058.git.esben@geanix.com> X-Mailer: git-send-email 2.44.0 MIME-Version: 1.0 X-Authenticated-Sender: esben@geanix.com X-Virus-Scanned: Clear (ClamAV 0.103.10/27235/Thu Apr 4 10:24:59 2024) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240405_022522_458369_241E24B9 X-CRM114-Status: GOOD ( 10.96 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org By waiting at most 1 second for USR2_TXDC to be set, we avoid a potentital deadlock. In case of the timeout, there is not much we can do, so we simply ignore the transmitter state and optimistically try to continue. Signed-off-by: Esben Haabendal Acked-by: Marc Kleine-Budde --- drivers/tty/serial/imx.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c index e14813250616..09c1678ddfd4 100644 --- a/drivers/tty/serial/imx.c +++ b/drivers/tty/serial/imx.c @@ -26,6 +26,7 @@ #include #include #include +#include #include #include @@ -2010,7 +2011,7 @@ imx_uart_console_write(struct console *co, const char *s, unsigned int count) struct imx_port *sport = imx_uart_ports[co->index]; struct imx_port_ucrs old_ucr; unsigned long flags; - unsigned int ucr1; + unsigned int ucr1, usr2; int locked = 1; if (sport->port.sysrq) @@ -2041,8 +2042,8 @@ imx_uart_console_write(struct console *co, const char *s, unsigned int count) * Finally, wait for transmitter to become empty * and restore UCR1/2/3 */ - while (!(imx_uart_readl(sport, USR2) & USR2_TXDC)); - + read_poll_timeout_atomic(imx_uart_readl, usr2, usr2 & USR2_TXDC, + 0, USEC_PER_SEC, false, sport, USR2); imx_uart_ucrs_restore(sport, &old_ucr); if (locked)