From: Krishna Reddy <vdumpa@nvidia.com>
To: Jonathan Hunter <jonathanh@nvidia.com>,
Robin Murphy <robin.murphy@arm.com>
Cc: Sachin Nikam <Snikam@nvidia.com>,
"nicoleotsuka@gmail.com" <nicoleotsuka@gmail.com>,
Mikko Perttunen <mperttunen@nvidia.com>,
Bryan Huntsman <bhuntsman@nvidia.com>,
"joro@8bytes.org" <joro@8bytes.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Pritesh Raithatha <praithatha@nvidia.com>,
Timo Alho <talho@nvidia.com>,
"iommu@lists.linux-foundation.org"
<iommu@lists.linux-foundation.org>,
Nicolin Chen <nicolinc@nvidia.com>,
"linux-tegra@vger.kernel.org" <linux-tegra@vger.kernel.org>,
Yu-Huan Hsu <YHsu@nvidia.com>,
Thierry Reding <treding@nvidia.com>,
"will@kernel.org" <will@kernel.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
Bitan Biswas <bbiswas@nvidia.com>
Subject: RE: [PATCH v8 2/3] dt-bindings: arm-smmu: Add binding for Tegra194 SMMU
Date: Wed, 1 Jul 2020 19:00:21 +0000 [thread overview]
Message-ID: <BYAPR12MB282245DD6BB50ECA700AC69EB36C0@BYAPR12MB2822.namprd12.prod.outlook.com> (raw)
In-Reply-To: <0d4f46d6-6a4e-bca0-bcf3-0e22a950e57b@nvidia.com>
>>>> + items:
>>>> + - enum:
>>>> + - nvdia,tegra194-smmu
>>>> + - const: arm,mmu-500
> >
>>> Is the fallback compatible appropriate here? If software treats this as a standard MMU-500 it will only program the first instance (because the second isn't presented as a separate MMU-500) - is there any way that isn't going to blow up?
> >
>> When compatible is set to both nvidia,tegra194-smmu and arm,mmu-500, implementation override ensure that both instances are programmed. Isn't it? I am not sure I follow your comment fully.
>The problem is, if for some reason someone had a Tegra194, but only set the compatible string to 'arm,mmu-500' it would assume that it was a normal arm,mmu-500 and only one instance would be programmed. We always want at least 2 of the 3 instances >programmed and so we should only match 'nvidia,tegra194-smmu'. In fact, I think that we also need to update the arm_smmu_of_match table to add 'nvidia,tegra194-smmu' with the data set to &arm_mmu500.
In that case, new binding "nvidia,smmu-v2" can be added with data set to &arm_mmu500 and enumeration would have nvidia,tegra194-smmu and another variant for next generation SoC in future.
-KR
--
nvpublic
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next prev parent reply other threads:[~2020-07-01 19:01 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-30 0:10 [PATCH v8 0/3] Nvidia Arm SMMUv2 Implementation Krishna Reddy
2020-06-30 0:10 ` [PATCH v8 1/3] iommu/arm-smmu: add NVIDIA implementation for dual ARM MMU-500 usage Krishna Reddy
2020-06-30 0:16 ` Nicolin Chen
2020-06-30 5:54 ` Pritesh Raithatha
2020-06-30 8:19 ` Jon Hunter
2020-06-30 14:53 ` Robin Murphy
2020-06-30 15:17 ` Jon Hunter
2020-07-01 18:18 ` Krishna Reddy
2020-07-01 18:56 ` Robin Murphy
2020-07-01 19:12 ` Krishna Reddy
2020-06-30 17:04 ` Krishna Reddy
2020-06-30 10:17 ` Jon Hunter
2020-06-30 16:23 ` Krishna Reddy
2020-06-30 16:32 ` Jon Hunter
2020-06-30 16:44 ` Jon Hunter
2020-06-30 17:16 ` Krishna Reddy
2020-06-30 19:03 ` Jon Hunter
2020-06-30 20:21 ` Krishna Reddy
2020-06-30 0:10 ` [PATCH v8 2/3] dt-bindings: arm-smmu: Add binding for Tegra194 SMMU Krishna Reddy
2020-06-30 6:01 ` Pritesh Raithatha
2020-06-30 8:21 ` Jon Hunter
2020-06-30 12:27 ` Robin Murphy
2020-07-01 18:28 ` Krishna Reddy
2020-07-01 18:47 ` Jon Hunter
2020-07-01 19:00 ` Krishna Reddy [this message]
2020-07-01 19:31 ` Jon Hunter
2020-07-01 19:39 ` Krishna Reddy
2020-07-02 16:05 ` Robin Murphy
2020-07-01 19:03 ` Robin Murphy
2020-06-30 0:10 ` [PATCH v8 3/3] iommu/arm-smmu: Add global/context fault implementation hooks Krishna Reddy
2020-06-30 0:19 ` Nicolin Chen
2020-06-30 5:58 ` Pritesh Raithatha
2020-06-30 8:37 ` Jon Hunter
2020-06-30 12:13 ` Robin Murphy
2020-06-30 12:42 ` Jon Hunter
2020-07-01 18:48 ` Krishna Reddy
2020-07-01 19:14 ` Robin Murphy
2020-07-01 19:22 ` Krishna Reddy
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