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=-9.0 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,T_DKIMWL_WL_HIGH,URIBL_BLOCKED,USER_AGENT_GIT 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 18506C28CC0 for ; Thu, 30 May 2019 09:12:03 +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 E68D225634 for ; Thu, 30 May 2019 09:12:02 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="S1vT2D5E" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E68D225634 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-Transfer-Encoding:Content-Type:MIME-Version:Cc:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id: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:In-Reply-To: References:List-Owner; bh=zdx1G6PrLPaweSi3I/N5lWv2OOdU7zUsVDXP/XN0V1E=; b=S1v T2D5E+UEazFMW1X5bP4b/UXKmggE5to7kjYkW6gZiNN6UbCn08gZ2Pl21Re/7cbGhmcYTSNhojwWY JKKV+88Xghqk1Nv7tBuZYQavzcTLdtgVt1rxkg8mshefdGbDi7+VUnlq6qj6aS2dA3ZPbPDeijWZn 5EPgynyyxAp8N5pdj0osEo86rTr2H1Nl76acHmPFRPt/H+QBOEP2T8mHXkp3Zy8OrvVzz1tCbKVNI bu8HBn5wQ7KmFKUAPHr1FZ0qBotOxusRHehpAnieYDV7c0WeqWQx2xGbL9GNXk56QXk1UXsVQUQyq VEEnu3/MC3tAl4PesskAzxoNo+WCzQg==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1hWH6K-0002gt-Ev; Thu, 30 May 2019 09:11:56 +0000 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70] helo=foss.arm.com) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1hWH6G-0002gE-EB for linux-arm-kernel@lists.infradead.org; Thu, 30 May 2019 09:11:54 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id C54C4A78; Thu, 30 May 2019 02:11:50 -0700 (PDT) Received: from usa.arm.com (e107155-lin.cambridge.arm.com [10.1.196.42]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 9125D3F59C; Thu, 30 May 2019 02:11:49 -0700 (PDT) From: Sudeep Holla To: linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org Subject: [PATCH] arm: dts: vexpress-v2p-ca15_a7: disable NOR flash node by default Date: Thu, 30 May 2019 10:11:39 +0100 Message-Id: <20190530091139.11643-1-sudeep.holla@arm.com> X-Mailer: git-send-email 2.17.1 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190530_021152_477982_3197D745 X-CRM114-Status: GOOD ( 14.50 ) 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: Linus Walleij , Lorenzo Pieralisi , Liviu Dudau , Sudeep Holla MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org Accessing the NOR flash memory from the kernel will disrupt CPU sleep/ idles states and CPU hotplugging. We need to disable this DT node by default. Setups that want to access the flash can modify this entry to enable the flash again but also ensuring to disable CPU idle states and CPU hotplug. The platform firmware assumes the flash is always in read mode while Linux kernel driver leaves NOR flash in "read id" mode after initialization. If it gets used actively, it can be in some other state. So far we had not seen this issue as the NOR flash drivers in kernel were not enabled by default. However it was enable in multi_v7 config by Commit 5f068190cc10 ("ARM: multi_v7_defconfig: Enable support for CFI NOR FLASH") So, let's mark the NOR flash disabled so that the platform can boot again. This based on: Commit 980bbff018f6 ("ARM64: juno: disable NOR flash node by default") Cc: Liviu Dudau Cc: Linus Walleij Cc: Lorenzo Pieralisi Signed-off-by: Sudeep Holla --- arch/arm/boot/dts/vexpress-v2m-rs1.dtsi | 2 +- arch/arm/boot/dts/vexpress-v2p-ca15_a7.dts | 9 +++++++++ 2 files changed, 10 insertions(+), 1 deletion(-) diff --git a/arch/arm/boot/dts/vexpress-v2m-rs1.dtsi b/arch/arm/boot/dts/vexpress-v2m-rs1.dtsi index d3963e9eaf48..1b5bc536c547 100644 --- a/arch/arm/boot/dts/vexpress-v2m-rs1.dtsi +++ b/arch/arm/boot/dts/vexpress-v2m-rs1.dtsi @@ -30,7 +30,7 @@ #interrupt-cells = <1>; ranges; - flash@0,00000000 { + nor_flash: flash@0,00000000 { compatible = "arm,vexpress-flash", "cfi-flash"; reg = <0 0x00000000 0x04000000>, <4 0x00000000 0x04000000>; diff --git a/arch/arm/boot/dts/vexpress-v2p-ca15_a7.dts b/arch/arm/boot/dts/vexpress-v2p-ca15_a7.dts index 164c904c9992..1de0a658adf1 100644 --- a/arch/arm/boot/dts/vexpress-v2p-ca15_a7.dts +++ b/arch/arm/boot/dts/vexpress-v2p-ca15_a7.dts @@ -680,3 +680,12 @@ <0 3 &gic 0 39 4>; }; }; + +&nor_flash { + /* + * Unfortunately, accessing the flash disturbs the CPU idle states + * (suspend) and CPU hotplug of this platform. For this reason, flash + * hardware access is disabled by default on this platform alone. + */ + status = "disabled"; +}; -- 2.17.1 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel