From patchwork Fri Mar 13 06:38:11 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Wang, Jiada" X-Patchwork-Id: 6002151 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 6C50BBF90F for ; Fri, 13 Mar 2015 06:40:34 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 92685201BB for ; Fri, 13 Mar 2015 06:40:33 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id A28D420114 for ; Fri, 13 Mar 2015 06:40:32 +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 1YWJF4-0004A5-QB; Fri, 13 Mar 2015 06:38:42 +0000 Received: from relay1.mentorg.com ([192.94.38.131]) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1YWJF1-000469-Rn for linux-arm-kernel@lists.infradead.org; Fri, 13 Mar 2015 06:38:40 +0000 Received: from svr-orw-fem-03.mgc.mentorg.com ([147.34.97.39]) by relay1.mentorg.com with esmtp id 1YWJEb-0000RA-26 from Jiada_Wang@mentor.com ; Thu, 12 Mar 2015 23:38:13 -0700 Received: from jiwang-OptiPlex-980.tokyo.mentorg.com (147.34.91.1) by svr-orw-fem-03.mgc.mentorg.com (147.34.97.39) with Microsoft SMTP Server id 14.3.224.2; Thu, 12 Mar 2015 23:38:12 -0700 From: Jiada Wang To: , , Subject: [PATCH] serial: imx: protect Soft Reset of port with lock Date: Fri, 13 Mar 2015 15:38:11 +0900 Message-ID: <1426228691-20529-1-git-send-email-jiada_wang@mentor.com> X-Mailer: git-send-email 1.9.3 MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20150312_233839_937137_A0096EF9 X-CRM114-Status: UNSURE ( 7.59 ) X-CRM114-Notice: Please train this message. X-Spam-Score: -0.7 (/) Cc: jiada_wang@mentor.com, linux-arm-kernel@lists.infradead.org X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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 Previously Soft Reset (clear of SRST bit in UCR2 register) of UART in startup is not protected by lock, which may have race with console_write, as console_write may occur at anytime even when UART port is shutdown. To avoid this race, protect Soft reset of UART port with spin_lock. Signed-off-by: Jiada Wang --- drivers/tty/serial/imx.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c index 0eb29b1..f81ccb1 100644 --- a/drivers/tty/serial/imx.c +++ b/drivers/tty/serial/imx.c @@ -1165,6 +1165,12 @@ static int imx_startup(struct uart_port *port) writel(temp & ~UCR4_DREN, sport->port.membase + UCR4); + /* Can we enable the DMA support? */ + if (is_imx6q_uart(sport) && !uart_console(port) && + !sport->dma_is_inited) + imx_uart_dma_init(sport); + + spin_lock_irqsave(&sport->port.lock, flags); /* Reset fifo's and state machines */ i = 100; @@ -1175,12 +1181,6 @@ static int imx_startup(struct uart_port *port) while (!(readl(sport->port.membase + UCR2) & UCR2_SRST) && (--i > 0)) udelay(1); - /* Can we enable the DMA support? */ - if (is_imx6q_uart(sport) && !uart_console(port) && - !sport->dma_is_inited) - imx_uart_dma_init(sport); - - spin_lock_irqsave(&sport->port.lock, flags); /* * Finally, clear and enable interrupts */