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[2001:1868:205::9]) by mx.google.com with ESMTPS id f5si69156063pat.158.2015.10.28.02.42.07 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 28 Oct 2015 02:42:07 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-arm-kernel-bounces+patch=linaro.org@lists.infradead.org designates 2001:1868:205::9 as permitted sender) client-ip=2001:1868:205::9; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-arm-kernel-bounces+patch=linaro.org@lists.infradead.org designates 2001:1868:205::9 as permitted sender) smtp.mailfrom=linux-arm-kernel-bounces+patch=linaro.org@lists.infradead.org; dkim=neutral (body hash did not verify) header.i=@linaro_org.20150623.gappssmtp.com 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 1ZrNE7-0005iF-RI; Wed, 28 Oct 2015 09:41:03 +0000 Received: from mail-lb0-x22a.google.com ([2a00:1450:4010:c04::22a]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1ZrNDT-0003uT-Nn for linux-arm-kernel@lists.infradead.org; Wed, 28 Oct 2015 09:40:26 +0000 Received: by lbbec13 with SMTP id ec13so1432793lbb.0 for ; Wed, 28 Oct 2015 02:40:01 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro_org.20150623.gappssmtp.com; s=20150623; h=from:to:cc:subject:date:message-id; bh=WIKxbwHt8oCGdiL4V7ZJefJb7P/UgvNArIuTbUIscEg=; b=mS2C6OFj/vdJod92Lq/Bt3+rv2eP+8cQokw05aiUTHBsrG34tO92OFA94RUqIu6p/I ZtPK0LQcEY0O9v3ic0bWQ2p1ClnTQHk0r/aL5C40LtpButZ4utwpzfD3NtWf9gRMLOZm iQPR+t28gPTiA3bthY17RrkVFt5QKQnvnKIiBP5PCESwFi9RR8oLOz2iyEhGQyA2JmLF d48ZDLra21nq9Yr6l3SQhlKWt0vcZ5VD7uAjKIDslFqC7XTV5N/ozC2dxgSyotODEeM7 Xi1+RbiBLJAB8/ZwtLEToMtA2pE75OlTgtSOpTERS3PoBU9rtUY220rczlRAgzhrC96f VnKg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=WIKxbwHt8oCGdiL4V7ZJefJb7P/UgvNArIuTbUIscEg=; b=l2a9WOQimOSQTtbW8nQeF04J08ivlFq4z0SHP6TQoHTdBdCGwA4Eh2XmBBlLZ8pT5q tUNdasgHL5cKOTcbVJ2Nf/NCDATNWe3PrUIUMQ7zwcUEF2oNaU9hDZa0aRpktwjTqH3B Eo4lyriiuLTLAHYDW9nimcajGQYp6wv24ajwuB0LScxOgwebAwchXxnmXBGAtPt7Xbf6 eu6jzxV/FK8YPcePUextY+2QFiWGXjPtAKKRoxnHbD2F7IcurKDiu3CHfS5IvZzqICby 5HFaLoKeloUyZJYs3amE4ddw5b1MiFYWQV92WQUALnL0D2apl+x7Ka2MXDwpk5mSBk2N bRog== X-Gm-Message-State: ALoCoQllkkyC/V8ZVGnaCGL0q7i9wsRnRAl7o+vUtTWH6Le11kG1WhfsyvSP1putLgMXo/3u3rpZ X-Received: by 10.112.198.69 with SMTP id ja5mr21675655lbc.106.1446025201581; Wed, 28 Oct 2015 02:40:01 -0700 (PDT) Received: from localhost.localdomain ([85.235.10.227]) by smtp.gmail.com with ESMTPSA id wj8sm7664120lbb.44.2015.10.28.02.39.59 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 28 Oct 2015 02:40:00 -0700 (PDT) From: Linus Walleij To: arm@kernel.org Subject: [PATCH] ARM64: juno: disable NOR flash node by default Date: Wed, 28 Oct 2015 10:39:55 +0100 Message-Id: <1446025195-9264-1-git-send-email-linus.walleij@linaro.org> X-Mailer: git-send-email 2.4.3 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20151028_024024_251238_BF0AA472 X-CRM114-Status: GOOD ( 15.87 ) X-Spam-Score: -2.6 (--) X-Spam-Report: SpamAssassin version 3.4.0 on bombadil.infradead.org summary: Content analysis details: (-2.6 points) pts rule name description ---- ---------------------- -------------------------------------------------- -0.7 RCVD_IN_DNSWL_LOW RBL: Sender listed at http://www.dnswl.org/, low trust [2a00:1450:4010:c04:0:0:0:22a listed in] [list.dnswl.org] -0.0 SPF_PASS SPF: sender matches SPF record -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] -0.1 DKIM_VALID Message has at least one valid DKIM or DK signature 0.1 DKIM_SIGNED Message has a DKIM or DK signature, not necessarily valid 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: Mark Rutland , Lorenzo Pieralisi , Catalin Marinas , Linus Walleij , Liviu Dudau , Ryan Harkin , Sudeep Holla , Leif Lindholm , linux-arm-kernel@lists.infradead.org MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patch=linaro.org@lists.infradead.org After discussing on the mailing list it turns out that accessing the flash memory from the kernel can disrupt CPU sleep states and CPU hotplugging, so let's disable this DT node by default. Setups that want to access the flash can modify this entry to enable the flash again. Quoting Sudeep Holla: "the firmware assumes the flash is always in read mode while Linux leaves NOR flash in "read id" mode after initialization." Reported-by: Sudeep Holla Cc: Mark Rutland Cc: Sudeep Holla Cc: Liviu Dudau Cc: Lorenzo Pieralisi Cc: Catalin Marinas Cc: Leif Lindholm Cc: Ryan Harkin Fixes: 5078f77e1443 "ARM64: juno: add NOR flash to device tree" Signed-off-by: Linus Walleij --- ARM SoC folks: please apply this as a fix for the upcoming v4.4 merge window, directly to the branch where the original commit resides (appears to be directly on the for-next branch or something). --- arch/arm64/boot/dts/arm/juno-motherboard.dtsi | 7 +++++++ 1 file changed, 7 insertions(+) -- 2.4.3 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel Acked-by: Sudeep Holla Acked-by: Mark Rutland diff --git a/arch/arm64/boot/dts/arm/juno-motherboard.dtsi b/arch/arm64/boot/dts/arm/juno-motherboard.dtsi index c7c99a42e2e9..8c029ee2a5b5 100644 --- a/arch/arm64/boot/dts/arm/juno-motherboard.dtsi +++ b/arch/arm64/boot/dts/arm/juno-motherboard.dtsi @@ -109,6 +109,13 @@ linux,part-probe = "afs"; reg = <0 0x00000000 0x04000000>; bank-width = <4>; + /* + * Unfortunately, accessing the flash disturbs + * the CPU idle states (suspend) and CPU + * hotplug of the platform. For this reason, + * flash hardware access is disabled by default. + */ + status = "disabled"; }; ethernet@2,00000000 {