From patchwork Sun Dec 6 04:39:18 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Soren Brinkmann X-Patchwork-Id: 7778081 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 18548BEEE1 for ; Sun, 6 Dec 2015 04:43:01 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 3A9EA204D5 for ; Sun, 6 Dec 2015 04:43:00 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 564CB20421 for ; Sun, 6 Dec 2015 04:42:59 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1a5R7k-0007Yk-Sw; Sun, 06 Dec 2015 04:40:36 +0000 Received: from mail-cys01nam02on0602.outbound.protection.outlook.com ([2a01:111:f400:fe45::602] helo=NAM02-CY1-obe.outbound.protection.outlook.com) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1a5R7O-0006Ki-SB for linux-arm-kernel@lists.infradead.org; Sun, 06 Dec 2015 04:40:17 +0000 Received: from CY1NAM02FT061.eop-nam02.prod.protection.outlook.com (10.152.74.53) by CY1NAM02HT143.eop-nam02.prod.protection.outlook.com (10.152.74.78) with Microsoft SMTP Server (TLS) id 15.1.346.13; Sun, 6 Dec 2015 04:39:52 +0000 Authentication-Results: spf=pass (sender IP is 149.199.60.83) smtp.mailfrom=xilinx.com; ettus.com; dkim=none (message not signed) header.d=none;ettus.com; dmarc=bestguesspass action=none header.from=xilinx.com; Received-SPF: Pass (protection.outlook.com: domain of xilinx.com designates 149.199.60.83 as permitted sender) receiver=protection.outlook.com; client-ip=149.199.60.83; helo=xsj-pvapsmtpgw01; Received: from xsj-pvapsmtpgw01 (149.199.60.83) by CY1NAM02FT061.mail.protection.outlook.com (10.152.75.30) with Microsoft SMTP Server (TLS) id 15.1.346.13 via Frontend Transport; Sun, 6 Dec 2015 04:39:51 +0000 Received: from unknown-38-66.xilinx.com ([149.199.38.66] helo=xsj-pvapsmtp01) by xsj-pvapsmtpgw01 with esmtp (Exim 4.63) (envelope-from ) id 1a5R71-0001wP-3H; Sat, 05 Dec 2015 20:39:51 -0800 Received: from [127.0.0.1] (helo=localhost) by xsj-pvapsmtp01 with smtp (Exim 4.63) (envelope-from ) id 1a5R70-0006eP-Uh; Sat, 05 Dec 2015 20:39:50 -0800 Received: from xsj-pvapsmtp01 (smtp.xilinx.com [149.199.38.66]) by xsj-smtp-dlp2.xlnx.xilinx.com (8.13.8/8.13.1) with ESMTP id tB64dff3009801; Sat, 5 Dec 2015 20:39:42 -0800 Received: from [172.19.74.49] (helo=localhost) by xsj-pvapsmtp01 with esmtp (Exim 4.63) (envelope-from ) id 1a5R6r-0006dK-QV; Sat, 05 Dec 2015 20:39:41 -0800 From: Soren Brinkmann To: Greg Kroah-Hartman , Jiri Slaby Subject: [PATCH LINUX v4 02/13] tty: xuartps: Use spinlock to serialize HW access Date: Sat, 5 Dec 2015 20:39:18 -0800 Message-ID: <1449376769-13369-3-git-send-email-soren.brinkmann@xilinx.com> X-Mailer: git-send-email 2.6.3.3.g9bb996a In-Reply-To: <1449376769-13369-1-git-send-email-soren.brinkmann@xilinx.com> References: <1449376769-13369-1-git-send-email-soren.brinkmann@xilinx.com> X-RCIS-Action: ALLOW X-TM-AS-Product-Ver: IMSS-7.1.0.1224-8.0.0.1202-21982.006 X-TM-AS-User-Approved-Sender: Yes;Yes X-EOPAttributedMessage: 0 X-Forefront-Antispam-Report: CIP:149.199.60.83; CTRY:US; IPV:NLI; EFV:NLI; SFV:NSPM; SFS:(10009020)(6009001)(2980300002)(438002)(189002)(199003)(63266004)(5001770100001)(1220700001)(57986006)(586003)(5008740100001)(36756003)(229853001)(19580405001)(77096005)(5001960100002)(1096002)(4001430100002)(47776003)(36386004)(19580395003)(87936001)(86362001)(50986999)(6806005)(50466002)(48376002)(2950100001)(107886002)(50226001)(92566002)(106466001)(81156007)(76176999)(76506005)(189998001)(5003940100001)(33646002)(107986001)(217873001); DIR:OUT; SFP:1101; SCL:1; SRVR:CY1NAM02HT143; H:xsj-pvapsmtpgw01; FPR:; SPF:Pass; PTR:unknown-60-83.xilinx.com; MX:1; A:1; LANG:en; MIME-Version: 1.0 X-Microsoft-Antispam: UriScan:; BCL:0; PCL:0; RULEID:(8251501001); SRVR:CY1NAM02HT143; X-Microsoft-Antispam-PRVS: X-Exchange-Antispam-Report-Test: UriScan:(192813158149592); X-Exchange-Antispam-Report-CFA-Test: BCL:0; PCL:0; RULEID:(601004)(2401047)(520078)(5005006)(8121501046)(3002001)(10201501046); SRVR:CY1NAM02HT143; BCL:0; PCL:0; RULEID:; SRVR:CY1NAM02HT143; X-Forefront-PRVS: 0782EC617F X-OriginatorOrg: xilinx.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 06 Dec 2015 04:39:51.5792 (UTC) X-MS-Exchange-CrossTenant-Id: 657af505-d5df-48d0-8300-c31994686c5c X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=657af505-d5df-48d0-8300-c31994686c5c; Ip=[149.199.60.83]; Helo=[xsj-pvapsmtpgw01] X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: CY1NAM02HT143 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20151205_204015_074810_617EC865 X-CRM114-Status: GOOD ( 10.27 ) X-Spam-Score: -1.9 (-) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Moritz Fischer , Peter Hurley , Michal Simek , linux-kernel@vger.kernel.org, Soren Brinkmann , linux-serial@vger.kernel.org, linux-arm-kernel@lists.infradead.org Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-4.2 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Instead of disabling the IRQ, use the spin lock to serialize accesses to the HW. This protects the driver from interference of non-IRQ callbacks with each other and makes the driver more consistent in its serialization method. Signed-off-by: Soren Brinkmann Reviewed-by: Peter Hurley --- drivers/tty/serial/xilinx_uartps.c | 18 ++++++------------ 1 file changed, 6 insertions(+), 12 deletions(-) diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c index 50d4082d2354..2c98c357d9a0 100644 --- a/drivers/tty/serial/xilinx_uartps.c +++ b/drivers/tty/serial/xilinx_uartps.c @@ -945,12 +945,10 @@ static void cdns_uart_set_mctrl(struct uart_port *port, unsigned int mctrl) #ifdef CONFIG_CONSOLE_POLL static int cdns_uart_poll_get_char(struct uart_port *port) { - u32 imr; int c; + unsigned long flags; - /* Disable all interrupts */ - imr = readl(port->membase + CDNS_UART_IMR_OFFSET); - writel(imr, port->membase + CDNS_UART_IDR_OFFSET); + spin_lock_irqsave(&port->lock, flags); /* Check if FIFO is empty */ if (readl(port->membase + CDNS_UART_SR_OFFSET) & CDNS_UART_SR_RXEMPTY) @@ -959,19 +957,16 @@ static int cdns_uart_poll_get_char(struct uart_port *port) c = (unsigned char) readl( port->membase + CDNS_UART_FIFO_OFFSET); - /* Enable interrupts */ - writel(imr, port->membase + CDNS_UART_IER_OFFSET); + spin_unlock_irqrestore(&port->lock, flags); return c; } static void cdns_uart_poll_put_char(struct uart_port *port, unsigned char c) { - u32 imr; + unsigned long flags; - /* Disable all interrupts */ - imr = readl(port->membase + CDNS_UART_IMR_OFFSET); - writel(imr, port->membase + CDNS_UART_IDR_OFFSET); + spin_lock_irqsave(&port->lock, flags); /* Wait until FIFO is empty */ while (!(readl(port->membase + CDNS_UART_SR_OFFSET) & @@ -986,8 +981,7 @@ static void cdns_uart_poll_put_char(struct uart_port *port, unsigned char c) CDNS_UART_SR_TXEMPTY)) cpu_relax(); - /* Enable interrupts */ - writel(imr, port->membase + CDNS_UART_IER_OFFSET); + spin_unlock_irqrestore(&port->lock, flags); return; }