From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.3 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1,WEIRD_QUOTING autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E6E02ECE58D for ; Wed, 9 Oct 2019 14:40:15 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id B8E4F20640 for ; Wed, 9 Oct 2019 14:40:15 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="EypYLiSw" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B8E4F20640 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender:Content-Type: Content-Transfer-Encoding:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date:Message-ID:From: References:To:Subject:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=Zm8zC2+m3WeWodPlHx1tIv7yLL0y54H67sr4+FXCE3A=; b=EypYLiSwI5dbmggi454k3XEOE styww4o5jkccj3h/FlevDxNKMccktT4p3oyiiU+lZQgb85rhbYejKHu6LE8ZtjnAIoZaxDsNQ3azp SsmWe7/4oYWC2dhx41NILJzaaxoz3mf/FSsru4bTNLmZlfEfAgr3cPsgIpTSE29MDgTX1uQutzJAP /rZVgQVvgMMCU+GsO/gOk7uAXkMl3dV8SSc974FecLER8q+5YsXsDqsh3C94DmO1DBQziJ4FcNqR4 6+CuO9HtW7UXsGg0HIqU7qtkdm08YA8j61j2XT6jY+5GyGov7HRke1uwh+asTDdUYF2MAt/+IsdYW Ma/lLG6Ww==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.2 #3 (Red Hat Linux)) id 1iID8L-0000C4-0Q; Wed, 09 Oct 2019 14:40:09 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.92.2 #3 (Red Hat Linux)) id 1iID8G-0007p1-Ut for linux-arm-kernel@lists.infradead.org; Wed, 09 Oct 2019 14:40:06 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id ACEA1337; Wed, 9 Oct 2019 07:40:02 -0700 (PDT) Received: from [10.1.197.57] (e110467-lin.cambridge.arm.com [10.1.197.57]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 725A43F71A; Wed, 9 Oct 2019 07:40:01 -0700 (PDT) Subject: Re: [PATCH] dts: Disable DMA support on the BK4 vf610 device's fsl_lpuart driver To: Lukasz Majewski , linux-kernel@vger.kernel.org, Shawn Guo References: <20191009143032.9261-1-lukma@denx.de> From: Robin Murphy Message-ID: Date: Wed, 9 Oct 2019 15:40:00 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: <20191009143032.9261-1-lukma@denx.de> Content-Language: en-GB X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20191009_074005_043553_0E7876BA X-CRM114-Status: GOOD ( 22.19 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , devicetree@vger.kernel.org, Sascha Hauer , Stefan Agner , Rob Herring , Pengutronix Kernel Team , linux-arm-kernel@lists.infradead.org Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 09/10/2019 15:30, Lukasz Majewski wrote: > This change disables the DMA support (RX/TX) on the NXP's fsl_lpuart > driver - the PIO mode is used instead. This change is necessary for better > robustness of BK4's device use cases with many potentially interrupted > short serial transfers. > > Without it the driver hangs when some distortion happens on UART lines. > > Signed-off-by: Lukasz Majewski > --- > arch/arm/boot/dts/vf610-bk4.dts | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/arch/arm/boot/dts/vf610-bk4.dts b/arch/arm/boot/dts/vf610-bk4.dts > index 0f3870d3b099..ad20f3442d40 100644 > --- a/arch/arm/boot/dts/vf610-bk4.dts > +++ b/arch/arm/boot/dts/vf610-bk4.dts > @@ -259,24 +259,28 @@ > &uart0 { > pinctrl-names = "default"; > pinctrl-0 = <&pinctrl_uart0>; > + dma-names = "",""; This looks like a horrible hack - is there any reason not to just strip things at compile-time, i.e. "/delete-property/ dmas;"? Robin. > status = "okay"; > }; > > &uart1 { > pinctrl-names = "default"; > pinctrl-0 = <&pinctrl_uart1>; > + dma-names = "",""; > status = "okay"; > }; > > &uart2 { > pinctrl-names = "default"; > pinctrl-0 = <&pinctrl_uart2>; > + dma-names = "",""; > status = "okay"; > }; > > &uart3 { > pinctrl-names = "default"; > pinctrl-0 = <&pinctrl_uart3>; > + dma-names = "",""; > status = "okay"; > }; > > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel