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Date: Thu, 29 Feb 2024 14:24:03 -0800
From: Chris Goldsworthy <quic_cgoldswo@quicinc.com>
To: Georgi Djakov <djakov@kernel.org>
CC: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>,
        Georgi Djakov
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        <krzysztof.kozlowski+dt@linaro.org>, <conor+dt@kernel.org>,
        <will@kernel.org>, <robin.murphy@arm.com>, <joro@8bytes.org>,
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Subject: Re: [PATCH v5 1/7] dt-bindings: iommu: Add Qualcomm TBU bindings
Message-ID: <20240229222347.GA918@hu-cgoldswo-sd.qualcomm.com>
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On Thu, Feb 29, 2024 at 10:09:34PM +0200, Georgi Djakov wrote:
> Hi Krzysztof,
> 
> On 29.02.24 19:53, Krzysztof Kozlowski wrote:
> >On 26/02/2024 18:22, Georgi Djakov wrote:
> >>+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> >>+%YAML 1.2
> >>+---
> >>+$id: http://devicetree.org/schemas/iommu/qcom,tbu.yaml#
> >>+$schema: http://devicetree.org/meta-schemas/core.yaml#
> >>+
> >>+title: Qualcomm TBU (Translation Buffer Unit)
> >>+
> >>+maintainers:
> >>+  - Georgi Djakov <quic_c_gdjako@quicinc.com>
> >>+
> >>+description:
> >>+  The Qualcomm SMMU500 implementation consists of TCU and TBU. The TBU contains
> >>+  a Translation Lookaside Buffer (TLB) that caches page tables. TBUs provides
> >>+  debug features to trace and trigger debug transactions. There are multiple TBU
> >>+  instances with each client core.
> >>+
> >>+properties:
> >>+  compatible:
> >>+    const: qcom,qsmmuv500-tbu
> >
> >Why we don't have SoC specific compatibles? If that's for SDM845, then
> >it should be qcom,sdm845-tbu or qcom,sdm845-qsmmuv500-tbu
> >
> 
> Because they should be all compatible (as registers). Adding a SoC compatible
> might get overly-specific, but i can also see the benefits in that, so ok will
> do it!
> 

Hi Krzysztof,

JFYI that the TBUs are used on our mobile SoCs going up until the SoC
we commercialized in early 2022, Snapdragon 8 Gen 1. Including SDM845
there are three more premium tier SoCs using TBUs plus all of their
value-tier derivatives.  There will also be prior generation premium
tier SoCs along with their derivatives that use the TBU as well. Does
it make sense to have a target-specific compatible string given this? 

Thanks,

Chris.