From patchwork Wed Aug 14 13:59:56 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marc Gonzalez X-Patchwork-Id: 13763536 Received: from ns.iliad.fr (ns.iliad.fr [212.27.33.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A68931B1507; Wed, 14 Aug 2024 14:00:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=212.27.33.1 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723644022; cv=none; b=N2tkXywI2HQFZdZa9cKFBub1OguWZ1+q2av/WzIOFlLOaNRK1Fuj7L9q1TcGS3EAE5xi+kRRNhmfMV/JMURJ2sFdoj9ujtnJE25vpcMQl3mqDCPV3B+wsw+fliT4y/Jw4PcmkvMW/f37LVoc+OndKmPLUY6SuhZ6U9+M+d/atz8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723644022; c=relaxed/simple; bh=RRdWvaaJjh2EukHMWmy8agmys/TF3UAfdsl3eILq5HQ=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=qwad2Wh4PE3q3s8Xce6XZ4Z8SXSuWT29q50tVVVVNJ+CwHG88U2xE1CLfg8RSObVtqYaJ8i/lBQufmaJ8HOaJW7UYjiy/WQ1Ff64Y3k1MZmYYsB7TXCzgc4DITEsycKtxsuESAlppBxFtOkYJIxzYC2qEVintGks6lYxvXSmTns= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=freebox.fr; spf=pass smtp.mailfrom=srs.iliad.fr; arc=none smtp.client-ip=212.27.33.1 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=freebox.fr Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=srs.iliad.fr Received: from ns.iliad.fr (localhost [127.0.0.1]) by ns.iliad.fr (Postfix) with ESMTP id DE9D42099D; Wed, 14 Aug 2024 16:00:09 +0200 (CEST) Received: from [127.0.1.1] (freebox.vlq16.iliad.fr [213.36.7.13]) by ns.iliad.fr (Postfix) with ESMTP id CE1972098C; Wed, 14 Aug 2024 16:00:09 +0200 (CEST) From: Marc Gonzalez Date: Wed, 14 Aug 2024 15:59:56 +0200 Subject: [PATCH 2/2] iommu/arm-smmu-qcom: hide last context bank from linux Precedence: bulk X-Mailing-List: linux-arm-msm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20240814-smmu-v1-2-3d6c27027d5b@freebox.fr> References: <20240814-smmu-v1-0-3d6c27027d5b@freebox.fr> In-Reply-To: <20240814-smmu-v1-0-3d6c27027d5b@freebox.fr> To: Rob Clark , Will Deacon , Robin Murphy , Joerg Roedel , Rob Herring , Krzysztof Kozlowski , Conor Dooley Cc: iommu@lists.linux.dev, linux-arm-msm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, Bjorn Andersson , Konrad Dybcio , Arnaud Vrac , Pierre-Hugues Husson , Marijn Suijten , Marc Gonzalez X-Mailer: b4 0.13.0 On qcom msm8998, writing to the last context bank of lpass_q6_smmu (base address 0x05100000) produces a system freeze & reboot. Specifically, here: qsmmu->bypass_cbndx = smmu->num_context_banks - 1; arm_smmu_cb_write(smmu, qsmmu->bypass_cbndx, ARM_SMMU_CB_SCTLR, 0); and here: arm_smmu_write_context_bank(smmu, i); arm_smmu_cb_write(smmu, i, ARM_SMMU_CB_FSR, ARM_SMMU_CB_FSR_FAULT); It is likely that FW reserves the last context bank for its own use, thus a simple work-around would be: DON'T USE IT in Linux. If we decrease the number of context banks, last one will be "hidden". Signed-off-by: Marc Gonzalez --- drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c index 7e65189ca7b8c..e2e1fd9e2452b 100644 --- a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c +++ b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c @@ -282,6 +282,11 @@ static int qcom_smmu_cfg_probe(struct arm_smmu_device *smmu) u32 smr; int i; + if (of_property_read_bool(smmu->dev->of_node, "qcom,last-ctx-bank-reserved")) { + dev_warn(smmu->dev, "hiding last ctx bank from linux"); + --smmu->num_context_banks; + } + /* * Some platforms support more than the Arm SMMU architected maximum of * 128 stream matching groups. For unknown reasons, the additional