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Date:   Mon, 20 Jul 2020 17:16:21 -0600
From:   Rob Herring <robh@kernel.org>
To:     Yong Wu <yong.wu@mediatek.com>
Cc:     Joerg Roedel <joro@8bytes.org>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        Robin Murphy <robin.murphy@arm.com>,
        Will Deacon <will@kernel.org>,
        Evan Green <evgreen@chromium.org>,
        Tomasz Figa <tfiga@google.com>,
        linux-mediatek@lists.infradead.org, srv_heupstream@mediatek.com,
        devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org,
        iommu@lists.linux-foundation.org, youlin.pei@mediatek.com,
        Nicolas Boichat <drinkcat@chromium.org>, anan.sun@mediatek.com,
        cui.zhang@mediatek.com, chao.hao@mediatek.com,
        ming-fan.chen@mediatek.com
Subject: Re: [PATCH 04/21] dt-binding: mediatek: Add binding for mt8192 IOMMU
 and SMI
Message-ID: <20200720231621.GA3106350@bogus>
References: <20200711064846.16007-1-yong.wu@mediatek.com>
 <20200711064846.16007-5-yong.wu@mediatek.com>
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On Sat, Jul 11, 2020 at 02:48:29PM +0800, Yong Wu wrote:
> This patch adds decriptions for mt8192 IOMMU and SMI.
> 
> mt8192 also is MTK IOMMU gen2 which uses ARM Short-Descriptor translation
> table format. The M4U-SMI HW diagram is as below:
> 
>                           EMI
>                            |
>                           M4U
>                            |
>                       ------------
>                        SMI Common
>                       ------------
>                            |
>   +-------+------+------+----------------------+-------+
>   |       |      |      |       ......         |       |
>   |       |      |      |                      |       |
> larb0   larb1  larb2  larb4     ......      larb19   larb20
> disp0   disp1   mdp    vdec                   IPE      IPE
> 
> All the connections are HW fixed, SW can NOT adjust it.
> 
> mt8192 M4U support 0~16GB iova range. we preassign different engines
> into different iova ranges:
> 
> domain-id  module     iova-range                  larbs
>    0       disp        0 ~ 4G                      larb0/1
>    1       vcodec      4G ~ 8G                     larb4/5/7
>    2       cam/mdp     8G ~ 12G             larb2/9/11/13/14/16/17/18/19/20
>    3       CCU0    0x4000_0000 ~ 0x43ff_ffff     larb13: port 9/10
>    4       CCU1    0x4400_0000 ~ 0x47ff_ffff     larb14: port 4/5

You probably want to use dma-ranges for defining these 
address restrictions. 

How is the domain-id used or needed?

Rob