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=-13.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable 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 4DEFEC433E2 for ; Fri, 11 Sep 2020 17:29:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1FE2C221E7 for ; Fri, 11 Sep 2020 17:29:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726322AbgIKR3p (ORCPT ); Fri, 11 Sep 2020 13:29:45 -0400 Received: from foss.arm.com ([217.140.110.172]:40348 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726504AbgIKR3d (ORCPT ); Fri, 11 Sep 2020 13:29:33 -0400 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 F213E106F; Fri, 11 Sep 2020 10:29:32 -0700 (PDT) Received: from [10.57.40.122] (unknown [10.57.40.122]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id E66493F68F; Fri, 11 Sep 2020 10:29:27 -0700 (PDT) Subject: Re: [PATCH v3 8/8] iommu/arm-smmu-qcom: Setup identity domain for boot mappings To: Bjorn Andersson , Will Deacon , Joerg Roedel , Sai Prakash Ranjan , Jordan Crouse , Rob Clark Cc: Sibi Sankar , linux-arm-kernel@lists.infradead.org, iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org References: <20200904155513.282067-1-bjorn.andersson@linaro.org> <20200904155513.282067-9-bjorn.andersson@linaro.org> From: Robin Murphy Message-ID: <34b1f9ea-fb16-faac-c288-627b51066968@arm.com> Date: Fri, 11 Sep 2020 18:29:23 +0100 User-Agent: Mozilla/5.0 (Windows NT 10.0; rv:68.0) Gecko/20100101 Thunderbird/68.12.0 MIME-Version: 1.0 In-Reply-To: <20200904155513.282067-9-bjorn.andersson@linaro.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-GB Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2020-09-04 16:55, Bjorn Andersson wrote: > With many Qualcomm platforms not having functional S2CR BYPASS a > temporary IOMMU domain, without translation, needs to be allocated in > order to allow these memory transactions. > > Unfortunately the boot loader uses the first few context banks, so > rather than overwriting a active bank the last context bank is used and > streams are diverted here during initialization. > > This also performs the readback of SMR registers for the Qualcomm > platform, to trigger the mechanism. > > This is based on prior work by Thierry Reding and Laurentiu Tudor. > > Signed-off-by: Bjorn Andersson > --- > > Changes since v2: > - Combined from pieces spread between the Qualcomm impl and generic code in v2. > - Moved to use the newly introduced inherit_mapping op. > > drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c | 33 ++++++++++++++++++++++ > 1 file changed, 33 insertions(+) > > diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c > index 70a1eaa52e14..a54302190932 100644 > --- a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c > +++ b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c > @@ -12,6 +12,7 @@ > struct qcom_smmu { > struct arm_smmu_device smmu; > bool bypass_broken; > + struct iommu_domain *identity; > }; > > static struct qcom_smmu *to_qcom_smmu(struct arm_smmu_device *smmu) > @@ -228,6 +229,37 @@ static int qcom_smmu_cfg_probe(struct arm_smmu_device *smmu) > return 0; > } > > +static int qcom_smmu_inherit_mappings(struct arm_smmu_device *smmu) > +{ > + struct qcom_smmu *qsmmu = to_qcom_smmu(smmu); > + int cbndx; > + u32 smr; > + int i; > + > + qsmmu->identity = arm_smmu_alloc_identity_domain(smmu); > + if (IS_ERR(qsmmu->identity)) > + return PTR_ERR(qsmmu->identity); > + > + cbndx = to_smmu_domain(qsmmu->identity)->cfg.cbndx; I don't really get the point of going through the dance of allocating a whole iommu_domain() just to get a context. If you don't want to simply statically reserve a context at probe time, then just allocate from smmu->context_map here (where AFAICS "here" should be in cfg_probe anyway). This is entirely driver-internal, so there shouldn't be any need for IOMMU-API-level stuff to be involved. Robin. > + > + for (i = 0; i < smmu->num_mapping_groups; i++) { > + smr = arm_smmu_gr0_read(smmu, ARM_SMMU_GR0_SMR(i)); > + > + if (FIELD_GET(ARM_SMMU_SMR_VALID, smr)) { > + smmu->smrs[i].id = FIELD_GET(ARM_SMMU_SMR_ID, smr); > + smmu->smrs[i].mask = FIELD_GET(ARM_SMMU_SMR_MASK, smr); > + smmu->smrs[i].valid = true; > + > + smmu->s2crs[i].type = S2CR_TYPE_TRANS; > + smmu->s2crs[i].privcfg = S2CR_PRIVCFG_DEFAULT; > + smmu->s2crs[i].cbndx = cbndx; > + smmu->s2crs[i].count++; > + } > + } > + > + return 0; > +} > + > static int qcom_smmu_def_domain_type(struct device *dev) > { > const struct of_device_id *match = > @@ -270,6 +302,7 @@ static const struct arm_smmu_impl qcom_smmu_impl = { > .cfg_probe = qcom_smmu_cfg_probe, > .def_domain_type = qcom_smmu_def_domain_type, > .reset = qcom_smmu500_reset, > + .inherit_mappings = qcom_smmu_inherit_mappings, > }; > > static const struct arm_smmu_impl qcom_adreno_smmu_impl = { >