From patchwork Fri Oct 6 10:13:36 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Miquel Raynal X-Patchwork-Id: 9988899 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id A5F7560247 for ; Fri, 6 Oct 2017 10:17:11 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 9B55328C2D for ; Fri, 6 Oct 2017 10:17:11 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 8E7D928C7B; Fri, 6 Oct 2017 10:17:11 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.2 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [65.50.211.133]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 27DF728C2D for ; Fri, 6 Oct 2017 10:17:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:MIME-Version:Cc:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id:References: In-Reply-To:Message-Id:Date:Subject:To:From:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Owner; bh=YZwR90D0BQrxam03EG+bOL6TEv3Vc2yuvCe3WopaVRQ=; b=MH+lKSpZuvNN7qgh7bXHqlMC2v kcNHLC5qRtCD6pldTjGnp399Gbk6J7ZX3BN+xP9hH4OV/yDBfaUCA2il2bbwdnvsMDr1W1+/3+D7z 4Ixxjdvte4OqyH4oPvUavrP6IdKvv3WgzU4d39LnUgsLoDD6RbuKUBe2ilBoD8LJldDKJnFuhGaRm r1OFo7Gk1PBiX774p3T17WmM0995eLsA4zIhYGzy53k+XGbiGM1ZkVMmOawpAGB374CvZm5sZDwfp uyhefwqTLmc8aO3RvAWRSLsQo3CPB7P7jLFw8fdooDC6NNO7E2DcLOKUOZ4gEPI2qJHUYD7Hqs0N3 ezHQucyg==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.87 #1 (Red Hat Linux)) id 1e0Pgn-0003qC-CD; Fri, 06 Oct 2017 10:17:05 +0000 Received: from mail.free-electrons.com ([62.4.15.54]) by bombadil.infradead.org with esmtp (Exim 4.87 #1 (Red Hat Linux)) id 1e0PeT-0000be-6p for linux-arm-kernel@lists.infradead.org; Fri, 06 Oct 2017 10:14:49 +0000 Received: by mail.free-electrons.com (Postfix, from userid 110) id D6B13209BA; Fri, 6 Oct 2017 12:14:11 +0200 (CEST) Received: from localhost.localdomain (LStLambert-657-1-97-87.w90-63.abo.wanadoo.fr [90.63.216.87]) by mail.free-electrons.com (Postfix) with ESMTPSA id 6A6B3209B0; Fri, 6 Oct 2017 12:14:11 +0200 (CEST) From: Miquel Raynal To: Greg Kroah-Hartman , Linus Walleij , Jason Cooper , Andrew Lunn , Gregory Clement , Sebastian Hesselbarth , Jiri Slaby , Catalin Marinas , Will Deacon Subject: [PATCH 08/16] serial: mvebu-uart: clear state register before IRQ request Date: Fri, 6 Oct 2017 12:13:36 +0200 Message-Id: <20171006101344.15590-9-miquel.raynal@free-electrons.com> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20171006101344.15590-1-miquel.raynal@free-electrons.com> References: <20171006101344.15590-1-miquel.raynal@free-electrons.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20171006_031442_186671_16051580 X-CRM114-Status: UNSURE ( 9.93 ) X-CRM114-Notice: Please train this message. X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Thomas Petazzoni , devicetree@vger.kernel.org, Allen Yan , Antoine Tenart , Nadav Haklai , linux-gpio@vger.kernel.org, linux-serial@vger.kernel.org, Miquel Raynal , Wilson Ding , linux-arm-kernel@lists.infradead.org MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP From: Allen Yan When receiving data on RX pin before ->uart_startup() is called, some error bits in the state register could be set up (like BRK_DET). This is harmless when using only the standard UART (error bits are read-only), but may procude an endless loop once in the extended UART RX interrupt handler (error bits must be cleared). Clear the status register in ->uart_startup() to avoid this situation. Signed-off-by: Allen Yan Signed-off-by: Miquel Raynal Reviewed-by: Gregory CLEMENT --- drivers/tty/serial/mvebu-uart.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/tty/serial/mvebu-uart.c b/drivers/tty/serial/mvebu-uart.c index 81a3d2714fd3..67f302748b78 100644 --- a/drivers/tty/serial/mvebu-uart.c +++ b/drivers/tty/serial/mvebu-uart.c @@ -322,6 +322,12 @@ static int mvebu_uart_startup(struct uart_port *port) writel(CTRL_TXFIFO_RST | CTRL_RXFIFO_RST, port->membase + UART_CTRL(port)); udelay(1); + + /* Clear the error bits of state register before IRQ request */ + ret = readl(port->membase + UART_STAT); + ret |= STAT_BRK_ERR; + writel(ret, port->membase + UART_STAT); + writel(CTRL_BRK_INT, port->membase + UART_CTRL(port)); ctl = readl(port->membase + UART_INTR(port));