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Message-ID: <YRwYFtVlNjxyRwX+@robh.at.kernel.org>
Date: Tue, 17 Aug 2021 15:12:06 -0500
From: Rob Herring <robh@...nel.org>
To: Yong Wu <yong.wu@...iatek.com>
Cc: Krzysztof Kozlowski <krzysztof.kozlowski@...onical.com>,
Matthias Brugger <matthias.bgg@...il.com>,
Krzysztof Kozlowski <krzk@...nel.org>,
Joerg Roedel <joro@...tes.org>, Will Deacon <will@...nel.org>,
Robin Murphy <robin.murphy@....com>,
Tomasz Figa <tfiga@...omium.org>,
linux-mediatek@...ts.infradead.org, srv_heupstream@...iatek.com,
linux-kernel@...r.kernel.org, devicetree@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org,
iommu@...ts.linux-foundation.org, youlin.pei@...iatek.com,
anan.sun@...iatek.com, ming-fan.chen@...iatek.com,
yi.kuo@...iatek.com, anthony.huang@...iatek.com,
Ikjoon Jang <ikjn@...omium.org>
Subject: Re: [PATCH v3 02/13] dt-bindings: memory: mediatek: Add mt8195 smi
sub common
On Tue, Aug 10, 2021 at 04:08:48PM +0800, Yong Wu wrote:
> Add the binding for smi-sub-common. The SMI block diagram like this:
>
> IOMMU
> | |
> smi-common
> ------------------
> | .... |
> larb0 larb7 <-max is 8
>
> The smi-common connects with smi-larb and IOMMU. The maximum larbs number
> that connects with a smi-common is 8. If the engines number is over 8,
> sometimes we use a smi-sub-common which is nearly same with smi-common.
> It supports up to 8 input and 1 output(smi-common has 2 output)
>
> Something like:
>
> IOMMU
> | |
> smi-common
> ---------------------
> | | ...
> larb0 sub-common ... <-max is 8
> -----------
> | | ... <-max is 8 too.
> larb2 larb5
>
> We don't need extra SW setting for smi-sub-common, only the sub-common has
> special clocks need to enable when the engines access dram.
>
> If it is sub-common, it should have a "mediatek,smi" phandle to point to
> its smi-common. meanwhile the sub-common only has one gals clock.
>
> Additionally, add a new property "mediatek,smi_sub_common" for this
> sub-common, this is needed in the IOMMU driver in which we create a device
> link between smi-common and the IOMMU device. If we add the smi-sub-common
> here, the IOMMU driver still need to find the smi-common device. thus,
> add this bool property to indicate if it is sub-common.
>
> Signed-off-by: Yong Wu <yong.wu@...iatek.com>
> ---
> change note:
> a. change mediatek, smi type from phandle-array to phandle from Rob.
> b. Add a new bool property (mediatek,smi_sub_common) to indicate this is
> smi-sub-common. the reason is as above.
> ---
> .../mediatek,smi-common.yaml | 30 +++++++++++++++++++
> 1 file changed, 30 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/memory-controllers/mediatek,smi-common.yaml b/Documentation/devicetree/bindings/memory-controllers/mediatek,smi-common.yaml
> index 602592b6c3f5..26bb9903864b 100644
> --- a/Documentation/devicetree/bindings/memory-controllers/mediatek,smi-common.yaml
> +++ b/Documentation/devicetree/bindings/memory-controllers/mediatek,smi-common.yaml
> @@ -38,6 +38,7 @@ properties:
> - mediatek,mt8192-smi-common
> - mediatek,mt8195-smi-common-vdo
> - mediatek,mt8195-smi-common-vpp
> + - mediatek,mt8195-smi-sub-common
>
> - description: for mt7623
> items:
> @@ -67,6 +68,14 @@ properties:
> minItems: 2
> maxItems: 4
>
> + mediatek,smi:
> + $ref: /schemas/types.yaml#/definitions/phandle
> + description: a phandle to the smi-common node above. Only for sub-common.
> +
> + mediatek,smi_sub_common:
s/_/-/
> + type: boolean
> + description: Indicate if this is smi-sub-common.
> +
> required:
> - compatible
> - reg
> @@ -93,6 +102,27 @@ allOf:
> - const: smi
> - const: async
>
> + - if: # only for sub common
> + properties:
> + compatible:
> + contains:
> + enum:
> + - mediatek,mt8195-smi-sub-common
> + then:
> + required:
> + - mediatek,smi
> + - mediatek,smi_sub_common
> + properties:
> + clock:
> + items:
> + minItems: 3
> + maxItems: 3
> + clock-names:
> + items:
> + - const: apb
> + - const: smi
> + - const: gals0
If not allowed for other compatibles, you need:
else:
properties:
mediatek,sni: false
mediatek,smi_sub_common: false
> +
> - if: # for gen2 HW that have gals
> properties:
> compatible:
> --
> 2.18.0
>
>
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