From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751923AbbLZKon (ORCPT ); Sat, 26 Dec 2015 05:44:43 -0500 Received: from mail-sn1nam02on0050.outbound.protection.outlook.com ([104.47.36.50]:46827 "EHLO NAM02-SN1-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751170AbbLZKnY (ORCPT ); Sat, 26 Dec 2015 05:43:24 -0500 Authentication-Results: spf=pass (sender IP is 149.199.60.100) smtp.mailfrom=xilinx.com; ettus.com; dkim=none (message not signed) header.d=none;ettus.com; dmarc=bestguesspass action=none header.from=xilinx.com; From: Soren Brinkmann To: Greg Kroah-Hartman , Jiri Slaby CC: Michal Simek , , , , "Peter Hurley" , Moritz Fischer , Soren Brinkmann Subject: [PATCH LINUX v5 3/8] tty: xuartps: Don't consider circular buffer when enabling transmitter Date: Sat, 26 Dec 2015 02:43:51 -0800 Message-ID: <1451126636-13699-4-git-send-email-soren.brinkmann@xilinx.com> X-Mailer: git-send-email 2.6.3.3.g9bb996a In-Reply-To: <1451126636-13699-1-git-send-email-soren.brinkmann@xilinx.com> References: <1451126636-13699-1-git-send-email-soren.brinkmann@xilinx.com> X-RCIS-Action: ALLOW X-TM-AS-Product-Ver: IMSS-7.1.0.1224-8.0.0.1202-22024.006 X-TM-AS-User-Approved-Sender: Yes;Yes X-EOPAttributedMessage: 0 X-Forefront-Antispam-Report: CIP:149.199.60.100;CTRY:US;IPV:NLI;EFV:NLI;SFV:NSPM;SFS:(10009020)(6009001)(2980300002)(438002)(189002)(199003)(189998001)(5003940100001)(63266004)(33646002)(36386004)(86362001)(19580405001)(11100500001)(106466001)(76506005)(2950100001)(50466002)(36756003)(81156007)(92566002)(1096002)(1220700001)(47776003)(87936001)(229853001)(50986999)(5001770100001)(586003)(77096005)(5008740100001)(5001960100002)(57986006)(107886002)(48376002)(19580395003)(76176999)(4001430100002)(6806005)(50226001)(107986001)(217873001)(5001870100001);DIR:OUT;SFP:1101;SCL:1;SRVR:CY1NAM02HT014;H:xsj-pvapsmtpgw02;FPR:;SPF:Pass;PTR:unknown-60-100.xilinx.com,xapps1.xilinx.com;MX:1;A:1;LANG:en; MIME-Version: 1.0 Content-Type: text/plain X-Microsoft-Antispam: UriScan:;BCL:0;PCL:0;RULEID:(8251501001);SRVR:CY1NAM02HT014; X-Microsoft-Antispam-PRVS: <497618698fc94c6f9eb0f4be3619567c@CY1NAM02HT014.eop-nam02.prod.protection.outlook.com> X-Exchange-Antispam-Report-Test: UriScan:(192813158149592); X-Exchange-Antispam-Report-CFA-Test: BCL:0;PCL:0;RULEID:(601004)(2401047)(520078)(5005006)(8121501046)(10201501046)(3002001);SRVR:CY1NAM02HT014;BCL:0;PCL:0;RULEID:;SRVR:CY1NAM02HT014; X-Forefront-PRVS: 0802ADD973 X-OriginatorOrg: xilinx.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 26 Dec 2015 10:43:21.1907 (UTC) X-MS-Exchange-CrossTenant-Id: 657af505-d5df-48d0-8300-c31994686c5c X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=657af505-d5df-48d0-8300-c31994686c5c;Ip=[149.199.60.100];Helo=[xsj-pvapsmtpgw02] X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: CY1NAM02HT014 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Restarting the transmitter even if the circ buffer is empty may be necessary to push out remaining data when the port is restarted after being stopped. Cc: Peter Hurley Signed-off-by: Soren Brinkmann Reviewed-by: Peter Hurley --- v3: - changed this patch to not always enable the transmitter, but keep the check for uart_tx_stopped() in place, as suggested by Peter, whose explanation I also stole for the new commit message (thx) --- drivers/tty/serial/xilinx_uartps.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c index 2c98c357d9a0..6a7cd4e057ae 100644 --- a/drivers/tty/serial/xilinx_uartps.c +++ b/drivers/tty/serial/xilinx_uartps.c @@ -512,7 +512,7 @@ static void cdns_uart_start_tx(struct uart_port *port) { unsigned int status, numbytes = port->fifosize; - if (uart_circ_empty(&port->state->xmit) || uart_tx_stopped(port)) + if (uart_tx_stopped(port)) return; /* @@ -524,6 +524,9 @@ static void cdns_uart_start_tx(struct uart_port *port) status |= CDNS_UART_CR_TX_EN; writel(status, port->membase + CDNS_UART_CR_OFFSET); + if (uart_circ_empty(&port->state->xmit)) + return; + while (numbytes-- && ((readl(port->membase + CDNS_UART_SR_OFFSET) & CDNS_UART_SR_TXFULL)) != CDNS_UART_SR_TXFULL) { /* Break if no more data available in the UART buffer */ -- 2.6.3.3.g9bb996a