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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 844E9E75438 for ; Tue, 3 Oct 2023 09:24:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239661AbjJCJYs (ORCPT ); Tue, 3 Oct 2023 05:24:48 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56246 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239587AbjJCJYq (ORCPT ); Tue, 3 Oct 2023 05:24:46 -0400 Received: from madras.collabora.co.uk (madras.collabora.co.uk [IPv6:2a00:1098:0:82:1000:25:2eeb:e5ab]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5858090; Tue, 3 Oct 2023 02:24:43 -0700 (PDT) Received: from [192.168.1.100] (2-237-20-237.ip236.fastwebnet.it [2.237.20.237]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (No client certificate requested) (Authenticated sender: kholk11) by madras.collabora.co.uk (Postfix) with ESMTPSA id 407F16607181; Tue, 3 Oct 2023 10:24:41 +0100 (BST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1696325081; bh=fglFS8/SJTxax6nKCOPR+u+mqyIQq4V/6eD+bn6enag=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=LscWssJW+MqsWczsrw3nIOSf0rtr6/nbmR7RS2yUbx4aYtZh7s4RCjGNaV3QD6wRu QTaHmxzxgPNanqdk82VRO4ntuWMg/MJTewnabeFJibpNUhYJ8mxZZrhqZ61k1tngh5 M8snckqZak/z4MzsCIfhP+LIFCMaZ9xyx6L1wzxnjameAwUwmvpEwcfRR8mIxakkNZ uLj9ZU6lp/D5zdfjSG64mY+kpUMITVqJ275VLFeoWvjsc8XnDAg3aeC97JHefwbgBz 176JTJWl1BYwnXq/ssMSysUxoSm/zqSF+ORF564joj8juOqkv0Er33JYejrco6J3Az GjqvtvLS4QchA== Message-ID: <1c639f51-a444-c8c8-8585-2e413243c3a6@collabora.com> Date: Tue, 3 Oct 2023 11:24:38 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.15.0 Subject: Re: [PATCH] arm64: dts: mediatek: mt8195: Set DSU PMU status to fail Content-Language: en-US To: =?UTF-8?B?TsOtY29sYXMgRi4gUi4gQS4gUHJhZG8=?= , Matthias Brugger Cc: kernel@collabora.com, Chen-Yu Tsai , Conor Dooley , Krzysztof Kozlowski , Rob Herring , Seiya Wang , Tinghan Shen , devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mediatek@lists.infradead.org References: <20230720200753.322133-1-nfraprado@collabora.com> From: AngeloGioacchino Del Regno In-Reply-To: <20230720200753.322133-1-nfraprado@collabora.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Il 20/07/23 22:07, Nícolas F. R. A. Prado ha scritto: > The DSU PMU allows monitoring performance events in the DSU cluster, > which is done by configuring and reading back values from the DSU PMU > system registers. However, for write-access to be allowed by ELs lower > than EL3, the EL3 firmware needs to update the setting on the ACTLR3_EL3 > register, as it is disallowed by default. > > That configuration is not done on the firmware used by the MT8195 SoC, > as a consequence, booting a MT8195-based machine like > mt8195-cherry-tomato-r2 with CONFIG_ARM_DSU_PMU enabled hangs the kernel > just as it writes to the CLUSTERPMOVSCLR_EL1 register, since the > instruction faults to EL3, and BL31 apparently just re-runs the > instruction over and over. > > Mark the DSU PMU node in the Devicetree with status "fail", as the > machine doesn't have a suitable firmware to make use of it from the > kernel, and allowing its driver to probe would hang the kernel. > > Fixes: 37f2582883be ("arm64: dts: Add mediatek SoC mt8195 and evaluation board") > Signed-off-by: Nícolas F. R. A. Prado > Reviewed-by: AngeloGioacchino Del Regno