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Date:   Sat, 18 Nov 2023 11:21:11 +0000
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Subject: Re: [PATCH v2 0/6] Add support for Translation Buffer Units
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To:     Georgi Djakov <quic_c_gdjako@quicinc.com>, robh+dt@kernel.org,
        krzysztof.kozlowski+dt@linaro.org, conor+dt@kernel.org,
        will@kernel.org, robin.murphy@arm.com, joro@8bytes.org
Cc:     devicetree@vger.kernel.org, andersson@kernel.org,
        konrad.dybcio@linaro.org, linux-arm-kernel@lists.infradead.org,
        iommu@lists.linux.dev, linux-kernel@vger.kernel.org,
        linux-arm-msm@vger.kernel.org, quic_cgoldswo@quicinc.com,
        quic_sukadev@quicinc.com, quic_pdaly@quicinc.com,
        quic_sudaraja@quicinc.com, djakov@kernel.org
References: <20231118042730.2799-1-quic_c_gdjako@quicinc.com>
From:   Bryan O'Donoghue <bryan.odonoghue@linaro.org>
In-Reply-To: <20231118042730.2799-1-quic_c_gdjako@quicinc.com>
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On 18/11/2023 04:27, Georgi Djakov wrote:
> The TCUs (Translation Control Units) and TBUs (Translation Buffer
> Units) are key components of the MMU-500. Multiple TBUs are connected
> to a single TCU over an interconnect. Each TBU contains a TLB that
> caches page tables. The MMU-500 implements a TBU for each connected
> master, and the TBU is designed, so that it is local to the master.
> 
> The Qualcomm SDM845 platform has an implementation of the SMMU-500,
> that has multiple TBUs. A DT schema is added to describe the resources
> for each TBU (register space, power-domains, interconnects and clocks).
> 
> The TBU driver will manage the resources and allow the system to
> operate the TBUs during a context fault to obtain details by doing
> s1 inv, software + hardware page table walks etc. This is implemented
> with ATOS/eCATs as the ATS feature is not supported. Being able to
> query the TBUs is useful for debugging various hardware/software
> issues on these platforms.
> 
> v2:
> - Improve DT binding description, add full example. (Konrad)
> - Drop Qcom specific stuff from the generic binding. (Rob)
> - Unconditionally try to populate subnodes. (Konrad)
> - Improve TBU driver commit text, remove memory barriers. (Bjorn)
> - Move TBU stuff into separate file. Make the driver builtin.
> - TODO: Evaluate whether to keep TBU support as a separate driver
>    or just instantiate things from qcom_smmu_impl_init()
> 
> v1: https://lore.kernel.org/r/20231019021923.13939-1-quic_c_gdjako@quicinc.com

What is your suggested way to test this series ?

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bod