[From nobody Sat Aug 16 21:14:08 2008 Return-Path: Received: from ganesha.gnumonks.org ([unix socket]) by ganesha (Cyrus v2.1.18-IPv6-Debian-2.1.18-1+sarge2) with LMTP; Wed, 04 Apr 2007 10:19:32 +0200 X-Sieve: CMU Sieve 2.2 Return-path: <linux-arm-kernel-bounces+laforge=gnumonks.org@lists.arm.linux.org.uk> Received: from [2002:c35c:fd02::1] (helo=ZenIV.linux.org.uk) by ganesha.gnumonks.org with esmtps (TLS-1.0:DHE_RSA_AES_256_CBC_SHA:32) (Exim 4.50) id 1HZ0iK-0004Oc-2G for laforge@gnumonks.org; Wed, 04 Apr 2007 10:19:32 +0200 Received: from lists.arm.linux.org.uk ([217.147.92.251]) by ZenIV.linux.org.uk with esmtpsa (Exim 4.52 #1 (Red Hat Linux)) id 1HZ0gk-0004aF-7f; Wed, 04 Apr 2007 09:17:57 +0100 Received: from localhost ([127.0.0.1] helo=lists.arm.linux.org.uk) by lists.arm.linux.org.uk with esmtp (Exim 4.50) id 1HZ0gW-0001cB-Td; Wed, 04 Apr 2007 09:17:40 +0100 Received: from www.osadl.org ([213.239.205.134] helo=mail.tglx.de) by lists.arm.linux.org.uk with esmtp (Exim 4.50) id 1HZ0eC-0001bU-Sk for linux-arm-kernel@lists.arm.linux.org.uk; Wed, 04 Apr 2007 09:15:22 +0100 Received: from hermes.tec.linutronix.de (unknown [192.168.0.1]) by mail.tglx.de (Postfix) with ESMTP id 3255365C292; Wed, 4 Apr 2007 10:15:11 +0200 (CEST) Received: from tglx.tec.linutronix.de (tglx.tec.linutronix.de [192.168.0.68]) by hermes.tec.linutronix.de (Postfix) with ESMTP id 6CC5F266DB4; Wed, 4 Apr 2007 10:15:10 +0200 (CEST) From: Thomas Gleixner <tglx@linutronix.de> To: Ben Dooks <ben-linux-arm@fluff.org> Content-Type: text/plain Date: Wed, 04 Apr 2007 10:15:28 +0200 Message-Id: <1175674528.28263.296.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.6.1 Content-Transfer-Encoding: 7bit X-Spam-Score: 0.1 (/); 186e8b483c7a847866f354868fcb7a8b X-Spam-Report: SpamAssassin version 3.0.3 on lists.arm.linux.org.uk summary: Content analysis details: (0.1 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- 0.1 FORGED_RCVD_HELO Received: contains a forged HELO Cc: linux-arm-kernel@lists.arm.linux.org.uk Subject: [PATCH] S3C24xx: Fix UART malfunction with RTSCTS enabled X-BeenThere: linux-arm-kernel@lists.arm.linux.org.uk X-Mailman-Version: 2.1.5 Precedence: list List-Id: ARM Linux kernel discussions <linux-arm-kernel.lists.arm.linux.org.uk> List-Unsubscribe: <http://lists.arm.linux.org.uk/mailman/listinfo/linux-arm-kernel>, <mailto:linux-arm-kernel-request@lists.arm.linux.org.uk?subject=unsubscribe> List-Archive: <http://lists.arm.linux.org.uk/pipermail/linux-arm-kernel> List-Post: <mailto:linux-arm-kernel@lists.arm.linux.org.uk> List-Help: <mailto:linux-arm-kernel-request@lists.arm.linux.org.uk?subject=help> List-Subscribe: <http://lists.arm.linux.org.uk/mailman/listinfo/linux-arm-kernel>, <mailto:linux-arm-kernel-request@lists.arm.linux.org.uk?subject=subscribe> Sender: linux-arm-kernel-bounces@lists.arm.linux.org.uk X-Spam-Score: 0.1 (/) X-Spam-Report: SpamAssassin version 3.0.4 on ZenIV.linux.org.uk summary: Content analysis details: (0.1 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- 0.1 FORGED_RCVD_HELO Received: contains a forged HELO Errors-To: linux-arm-kernel-bounces+laforge=gnumonks.org+laforge=gnumonks.org@lists.arm.linux.org.uk X-Spam-Score: 0.1 (/) X-Spam-Report: SpamASsassin versoin 3.0.3 on ganesha.gnumonks.org summary: Content analysis details: (0.1 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- 0.1 FORGED_RCVD_HELO Received: contains a forged HELO The S3C24xx UARTs have an Automatic Flow Control feature, which handles the hardware handshake via RTS/CTS itself. A change on the cts line does not result in an interrupt. When the UART is configured for hardware handshake the serial core code reads the status of the CTS line. If the line status indicates that the connected device is not ready to receive data, then the uart is blocked until the status of the CTS line changes. Due to the missing CTS change interrupt the UART transmit side is blocked for ever. Change the modem control status read function so it returns with TIOCM_CTS set, when the AFC feature is enabled. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> diff --git a/drivers/serial/s3c2410.c b/drivers/serial/s3c2410.c index 3ba9208..650aec3 100644 --- a/drivers/serial/s3c2410.c +++ b/drivers/serial/s3c2410.c @@ -458,8 +458,21 @@ static unsigned int s3c24xx_serial_tx_empty(struct uart_port *port) static unsigned int s3c24xx_serial_get_mctrl(struct uart_port *port) { unsigned int umstat = rd_regb(port,S3C2410_UMSTAT); + unsigned int umcon = S3C2410_UMCOM_AFC; - if (umstat & S3C2410_UMSTAT_CTS) + /* + * The 3rd does not support handshake lines, so we avoid to + * read from the control register. + */ + if (port->line < 2) + umcon = rd_regb(port, S3C2410_UMCON); + + /* + * Return the status of the CTS line only when AFC is turned + * off. Otherwise the logic in serial_core might disable the + * uart for ever. + */ + if ((umstat & S3C2410_UMSTAT_CTS) || (umcon & S3C2410_UMCOM_AFC)) return TIOCM_CAR | TIOCM_DSR | TIOCM_CTS; else return TIOCM_CAR | TIOCM_DSR; ------------------------------------------------------------------- List admin: http://lists.arm.linux.org.uk/mailman/listinfo/linux-arm-kernel FAQ: http://www.arm.linux.org.uk/mailinglists/faq.php Etiquette: http://www.arm.linux.org.uk/mailinglists/etiquette.php ]