diff mbox series

[v2,01/23] dt-bindings: iommu: mediatek: Convert IOMMU to DT schema

Message ID 20200905080920.13396-2-yong.wu@mediatek.com
State Changes Requested, archived
Headers show
Series MT8192 IOMMU support | expand

Checks

Context Check Description
robh/checkpatch warning total: 0 errors, 2 warnings, 150 lines checked
robh/dt-meta-schema success

Commit Message

Yong Wu Sept. 5, 2020, 8:08 a.m. UTC
Convert MediaTek IOMMU to DT schema.

Signed-off-by: Yong Wu <yong.wu@mediatek.com>
---
 .../bindings/iommu/mediatek,iommu.txt         | 103 ------------
 .../bindings/iommu/mediatek,iommu.yaml        | 150 ++++++++++++++++++
 2 files changed, 150 insertions(+), 103 deletions(-)
 delete mode 100644 Documentation/devicetree/bindings/iommu/mediatek,iommu.txt
 create mode 100644 Documentation/devicetree/bindings/iommu/mediatek,iommu.yaml

Comments

Rob Herring (Arm) Sept. 14, 2020, 11:22 p.m. UTC | #1
On Sat, Sep 05, 2020 at 04:08:58PM +0800, Yong Wu wrote:
> Convert MediaTek IOMMU to DT schema.
> 
> Signed-off-by: Yong Wu <yong.wu@mediatek.com>
> ---
>  .../bindings/iommu/mediatek,iommu.txt         | 103 ------------
>  .../bindings/iommu/mediatek,iommu.yaml        | 150 ++++++++++++++++++
>  2 files changed, 150 insertions(+), 103 deletions(-)
>  delete mode 100644 Documentation/devicetree/bindings/iommu/mediatek,iommu.txt
>  create mode 100644 Documentation/devicetree/bindings/iommu/mediatek,iommu.yaml
> 
> diff --git a/Documentation/devicetree/bindings/iommu/mediatek,iommu.txt b/Documentation/devicetree/bindings/iommu/mediatek,iommu.txt
> deleted file mode 100644
> index c1ccd8582eb2..000000000000
> --- a/Documentation/devicetree/bindings/iommu/mediatek,iommu.txt
> +++ /dev/null
> @@ -1,103 +0,0 @@
> -* Mediatek IOMMU Architecture Implementation
> -
> -  Some Mediatek SOCs contain a Multimedia Memory Management Unit (M4U), and
> -this M4U have two generations of HW architecture. Generation one uses flat
> -pagetable, and only supports 4K size page mapping. Generation two uses the
> -ARM Short-Descriptor translation table format for address translation.
> -
> -  About the M4U Hardware Block Diagram, please check below:
> -
> -              EMI (External Memory Interface)
> -               |
> -              m4u (Multimedia Memory Management Unit)
> -               |
> -          +--------+
> -          |        |
> -      gals0-rx   gals1-rx    (Global Async Local Sync rx)
> -          |        |
> -          |        |
> -      gals0-tx   gals1-tx    (Global Async Local Sync tx)
> -          |        |          Some SoCs may have GALS.
> -          +--------+
> -               |
> -           SMI Common(Smart Multimedia Interface Common)
> -               |
> -       +----------------+-------
> -       |                |
> -       |             gals-rx        There may be GALS in some larbs.
> -       |                |
> -       |                |
> -       |             gals-tx
> -       |                |
> -   SMI larb0        SMI larb1   ... SoCs have several SMI local arbiter(larb).
> -   (display)         (vdec)
> -       |                |
> -       |                |
> - +-----+-----+     +----+----+
> - |     |     |     |    |    |
> - |     |     |...  |    |    |  ... There are different ports in each larb.
> - |     |     |     |    |    |
> -OVL0 RDMA0 WDMA0  MC   PP   VLD
> -
> -  As above, The Multimedia HW will go through SMI and M4U while it
> -access EMI. SMI is a bridge between m4u and the Multimedia HW. It contain
> -smi local arbiter and smi common. It will control whether the Multimedia
> -HW should go though the m4u for translation or bypass it and talk
> -directly with EMI. And also SMI help control the power domain and clocks for
> -each local arbiter.
> -  Normally we specify a local arbiter(larb) for each multimedia HW
> -like display, video decode, and camera. And there are different ports
> -in each larb. Take a example, There are many ports like MC, PP, VLD in the
> -video decode local arbiter, all these ports are according to the video HW.
> -  In some SoCs, there may be a GALS(Global Async Local Sync) module between
> -smi-common and m4u, and additional GALS module between smi-larb and
> -smi-common. GALS can been seen as a "asynchronous fifo" which could help
> -synchronize for the modules in different clock frequency.
> -
> -Required properties:
> -- compatible : must be one of the following string:
> -	"mediatek,mt2701-m4u" for mt2701 which uses generation one m4u HW.
> -	"mediatek,mt2712-m4u" for mt2712 which uses generation two m4u HW.
> -	"mediatek,mt6779-m4u" for mt6779 which uses generation two m4u HW.
> -	"mediatek,mt7623-m4u", "mediatek,mt2701-m4u" for mt7623 which uses
> -						     generation one m4u HW.
> -	"mediatek,mt8173-m4u" for mt8173 which uses generation two m4u HW.
> -	"mediatek,mt8183-m4u" for mt8183 which uses generation two m4u HW.
> -- reg : m4u register base and size.
> -- interrupts : the interrupt of m4u.
> -- clocks : must contain one entry for each clock-names.
> -- clock-names : Only 1 optional clock:
> -  - "bclk": the block clock of m4u.
> -  Here is the list which require this "bclk":
> -  - mt2701, mt2712, mt7623 and mt8173.
> -  Note that m4u use the EMI clock which always has been enabled before kernel
> -  if there is no this "bclk".
> -- mediatek,larbs : List of phandle to the local arbiters in the current Socs.
> -	Refer to bindings/memory-controllers/mediatek,smi-larb.txt. It must sort
> -	according to the local arbiter index, like larb0, larb1, larb2...
> -- iommu-cells : must be 1. This is the mtk_m4u_id according to the HW.
> -	Specifies the mtk_m4u_id as defined in
> -	dt-binding/memory/mt2701-larb-port.h for mt2701, mt7623
> -	dt-binding/memory/mt2712-larb-port.h for mt2712,
> -	dt-binding/memory/mt6779-larb-port.h for mt6779,
> -	dt-binding/memory/mt8173-larb-port.h for mt8173, and
> -	dt-binding/memory/mt8183-larb-port.h for mt8183.
> -
> -Example:
> -	iommu: iommu@10205000 {
> -		compatible = "mediatek,mt8173-m4u";
> -		reg = <0 0x10205000 0 0x1000>;
> -		interrupts = <GIC_SPI 139 IRQ_TYPE_LEVEL_LOW>;
> -		clocks = <&infracfg CLK_INFRA_M4U>;
> -		clock-names = "bclk";
> -		mediatek,larbs = <&larb0 &larb1 &larb2 &larb3 &larb4 &larb5>;
> -		#iommu-cells = <1>;
> -	};
> -
> -Example for a client device:
> -	display {
> -		compatible = "mediatek,mt8173-disp";
> -		iommus = <&iommu M4U_PORT_DISP_OVL0>,
> -			 <&iommu M4U_PORT_DISP_RDMA0>;
> -		...
> -	};
> diff --git a/Documentation/devicetree/bindings/iommu/mediatek,iommu.yaml b/Documentation/devicetree/bindings/iommu/mediatek,iommu.yaml
> new file mode 100644
> index 000000000000..d7b31bda3e35
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/iommu/mediatek,iommu.yaml
> @@ -0,0 +1,150 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/iommu/mediatek,iommu.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: MediaTek IOMMU Architecture Implementation
> +
> +maintainers:
> +  - Yong Wu <yong.wu@mediatek.com>
> +  - Chao Hao <chao.hao@mediatek.com>
> +
> +description: |+
> +  Some MediaTek SOCs contain a Multimedia Memory Management Unit (M4U), and
> +  this M4U have two generations of HW architecture. Generation one uses flat
> +  pagetable, and only supports 4K size page mapping. Generation two uses the
> +  ARM Short-Descriptor translation table format for address translation.
> +
> +  About the M4U Hardware Block Diagram, please check below:
> +
> +                EMI (External Memory Interface)
> +                 |
> +                m4u (Multimedia Memory Management Unit)
> +                 |
> +            +--------+
> +            |        |
> +        gals0-rx   gals1-rx    (Global Async Local Sync rx)
> +            |        |
> +            |        |
> +        gals0-tx   gals1-tx    (Global Async Local Sync tx)
> +            |        |          Some SoCs may have GALS.
> +            +--------+
> +                 |
> +             SMI Common(Smart Multimedia Interface Common)
> +                 |
> +         +----------------+-------
> +         |                |
> +         |             gals-rx        There may be GALS in some larbs.
> +         |                |
> +         |                |
> +         |             gals-tx
> +         |                |
> +     SMI larb0        SMI larb1   ... SoCs have several SMI local arbiter(larb).
> +     (display)         (vdec)
> +         |                |
> +         |                |
> +   +-----+-----+     +----+----+
> +   |     |     |     |    |    |
> +   |     |     |...  |    |    |  ... There are different ports in each larb.
> +   |     |     |     |    |    |
> +  OVL0 RDMA0 WDMA0  MC   PP   VLD
> +
> +  As above, The Multimedia HW will go through SMI and M4U while it
> +  access EMI. SMI is a bridge between m4u and the Multimedia HW. It contain
> +  smi local arbiter and smi common. It will control whether the Multimedia
> +  HW should go though the m4u for translation or bypass it and talk
> +  directly with EMI. And also SMI help control the power domain and clocks for
> +  each local arbiter.
> +
> +  Normally we specify a local arbiter(larb) for each multimedia HW
> +  like display, video decode, and camera. And there are different ports
> +  in each larb. Take a example, There are many ports like MC, PP, VLD in the
> +  video decode local arbiter, all these ports are according to the video HW.
> +
> +  In some SoCs, there may be a GALS(Global Async Local Sync) module between
> +  smi-common and m4u, and additional GALS module between smi-larb and
> +  smi-common. GALS can been seen as a "asynchronous fifo" which could help
> +  synchronize for the modules in different clock frequency.
> +
> +properties:
> +  compatible:
> +    enum:
> +      - mediatek,mt2701-m4u #mt2701 generation one HW
> +      - mediatek,mt2712-m4u #mt2712 generation two HW
> +      - mediatek,mt6779-m4u #mt6779 generation two HW
> +      - mediatek,mt7623-m4u, mediatek,mt2701-m4u #mt7623 generation one HW

This is not right.

items:
  - const: mediatek,mt7623-m4u
  - const: mediatek,mt2701-m4u

And that has to be under a 'oneOf' with the rest of this.

> +      - mediatek,mt8173-m4u #mt8173 generation two HW
> +      - mediatek,mt8183-m4u #mt8183 generation two HW
> +
> +  reg:
> +    maxItems: 1
> +
> +  interrupts:
> +    maxItems: 1
> +
> +  clocks:
> +    description: |
> +      bclk is optional. here is the list which require this bclk:
> +      mt2701, mt2712, mt7623 and mt8173.
> +      M4U will use the EMI clock which always has been enabled before
> +      kernel if there is no this bclk.
> +    items:
> +      - description: bclk is the block clock.
> +
> +  clock-names:
> +    items:
> +      - const: bclk
> +
> +  mediatek,larbs:
> +    $ref: /schemas/types.yaml#/definitions/phandle-array
> +    description: |
> +      List of phandle to the local arbiters in the current Socs.
> +      Refer to bindings/memory-controllers/mediatek,smi-larb.yaml. It must sort
> +      according to the local arbiter index, like larb0, larb1, larb2...
> +
> +  '#iommu-cells':
> +    const: 1
> +    description: |
> +      This is the mtk_m4u_id according to the HW. Specifies the mtk_m4u_id as
> +      defined in
> +      dt-binding/memory/mt2701-larb-port.h for mt2701 and mt7623,
> +      dt-binding/memory/mt2712-larb-port.h for mt2712,
> +      dt-binding/memory/mt6779-larb-port.h for mt6779,
> +      dt-binding/memory/mt8173-larb-port.h for mt8173,
> +      dt-binding/memory/mt8183-larb-port.h for mt8183.
> +
> +required:
> +  - compatible
> +  - reg
> +  - interrupts
> +  - mediatek,larbs
> +  - '#iommu-cells'
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    #include <dt-bindings/clock/mt8173-clk.h>
> +    #include <dt-bindings/interrupt-controller/arm-gic.h>
> +
> +    iommu: iommu@10205000 {
> +            compatible = "mediatek,mt8173-m4u";
> +            reg = <0x10205000 0x1000>;
> +            interrupts = <GIC_SPI 139 IRQ_TYPE_LEVEL_LOW>;
> +            clocks = <&infracfg CLK_INFRA_M4U>;
> +            clock-names = "bclk";
> +            mediatek,larbs = <&larb0 &larb1 &larb2
> +                              &larb3 &larb4 &larb5>;
> +            #iommu-cells = <1>;
> +    };
> +
> +  - |
> +    #include <dt-bindings/memory/mt8173-larb-port.h>
> +
> +    /* Example for a client device */
> +    display {
> +           compatible = "mediatek,mt8173-disp";
> +           iommus = <&iommu M4U_PORT_DISP_OVL0>,
> +                    <&iommu M4U_PORT_DISP_RDMA0>;
> +     };
> -- 
> 2.18.0
Yong Wu Sept. 15, 2020, 5:49 a.m. UTC | #2
On Mon, 2020-09-14 at 17:22 -0600, Rob Herring wrote:
> On Sat, Sep 05, 2020 at 04:08:58PM +0800, Yong Wu wrote:
> > Convert MediaTek IOMMU to DT schema.
> > 
> > Signed-off-by: Yong Wu <yong.wu@mediatek.com>
> > ---

[...]

> > +properties:
> > +  compatible:
> > +    enum:
> > +      - mediatek,mt2701-m4u #mt2701 generation one HW
> > +      - mediatek,mt2712-m4u #mt2712 generation two HW
> > +      - mediatek,mt6779-m4u #mt6779 generation two HW
> > +      - mediatek,mt7623-m4u, mediatek,mt2701-m4u #mt7623 generation one HW
> 
> This is not right.
> 
> items:
>   - const: mediatek,mt7623-m4u
>   - const: mediatek,mt2701-m4u
> 
> And that has to be under a 'oneOf' with the rest of this.

Thanks for the review. Is this OK?

  compatible:
    oneOf:
      - const: mediatek,mt2701-m4u # mt2701 generation one HW
      - const: mediatek,mt2712-m4u # mt2712 generation two HW
      - const: mediatek,mt6779-m4u # mt6779 generation two HW
      - const: mediatek,mt8173-m4u # mt8173 generation two HW
      - const: mediatek,mt8183-m4u # mt8183 generation two HW
      - const: mediatek,mt8192-m4u # mt8192 generation two HW
            
      - description: mt7623 generation one HW
        items:
          - const: mediatek,mt7623-m4u
          - const: mediatek,mt2701-m4u

> 
> > +      - mediatek,mt8173-m4u #mt8173 generation two HW
> > +      - mediatek,mt8183-m4u #mt8183 generation two HW
> > +
> > +  reg:
> > +    maxItems: 1

[snip]
Rob Herring (Arm) Sept. 18, 2020, 4:07 p.m. UTC | #3
On Mon, Sep 14, 2020 at 11:51 PM Yong Wu <yong.wu@mediatek.com> wrote:
>
> On Mon, 2020-09-14 at 17:22 -0600, Rob Herring wrote:
> > On Sat, Sep 05, 2020 at 04:08:58PM +0800, Yong Wu wrote:
> > > Convert MediaTek IOMMU to DT schema.
> > >
> > > Signed-off-by: Yong Wu <yong.wu@mediatek.com>
> > > ---
>
> [...]
>
> > > +properties:
> > > +  compatible:
> > > +    enum:
> > > +      - mediatek,mt2701-m4u #mt2701 generation one HW
> > > +      - mediatek,mt2712-m4u #mt2712 generation two HW
> > > +      - mediatek,mt6779-m4u #mt6779 generation two HW
> > > +      - mediatek,mt7623-m4u, mediatek,mt2701-m4u #mt7623 generation one HW
> >
> > This is not right.
> >
> > items:
> >   - const: mediatek,mt7623-m4u
> >   - const: mediatek,mt2701-m4u
> >
> > And that has to be under a 'oneOf' with the rest of this.
>
> Thanks for the review. Is this OK?
>
>   compatible:
>     oneOf:
>       - const: mediatek,mt2701-m4u # mt2701 generation one HW
>       - const: mediatek,mt2712-m4u # mt2712 generation two HW
>       - const: mediatek,mt6779-m4u # mt6779 generation two HW
>       - const: mediatek,mt8173-m4u # mt8173 generation two HW
>       - const: mediatek,mt8183-m4u # mt8183 generation two HW
>       - const: mediatek,mt8192-m4u # mt8192 generation two HW

It is correct, but I prefer all these to be a single enum. So 'oneOf'
would have 2 entries.

>       - description: mt7623 generation one HW
>         items:
>           - const: mediatek,mt7623-m4u
>           - const: mediatek,mt2701-m4u
>
> >
> > > +      - mediatek,mt8173-m4u #mt8173 generation two HW
> > > +      - mediatek,mt8183-m4u #mt8183 generation two HW
> > > +
> > > +  reg:
> > > +    maxItems: 1
>
> [snip]
diff mbox series

Patch

diff --git a/Documentation/devicetree/bindings/iommu/mediatek,iommu.txt b/Documentation/devicetree/bindings/iommu/mediatek,iommu.txt
deleted file mode 100644
index c1ccd8582eb2..000000000000
--- a/Documentation/devicetree/bindings/iommu/mediatek,iommu.txt
+++ /dev/null
@@ -1,103 +0,0 @@ 
-* Mediatek IOMMU Architecture Implementation
-
-  Some Mediatek SOCs contain a Multimedia Memory Management Unit (M4U), and
-this M4U have two generations of HW architecture. Generation one uses flat
-pagetable, and only supports 4K size page mapping. Generation two uses the
-ARM Short-Descriptor translation table format for address translation.
-
-  About the M4U Hardware Block Diagram, please check below:
-
-              EMI (External Memory Interface)
-               |
-              m4u (Multimedia Memory Management Unit)
-               |
-          +--------+
-          |        |
-      gals0-rx   gals1-rx    (Global Async Local Sync rx)
-          |        |
-          |        |
-      gals0-tx   gals1-tx    (Global Async Local Sync tx)
-          |        |          Some SoCs may have GALS.
-          +--------+
-               |
-           SMI Common(Smart Multimedia Interface Common)
-               |
-       +----------------+-------
-       |                |
-       |             gals-rx        There may be GALS in some larbs.
-       |                |
-       |                |
-       |             gals-tx
-       |                |
-   SMI larb0        SMI larb1   ... SoCs have several SMI local arbiter(larb).
-   (display)         (vdec)
-       |                |
-       |                |
- +-----+-----+     +----+----+
- |     |     |     |    |    |
- |     |     |...  |    |    |  ... There are different ports in each larb.
- |     |     |     |    |    |
-OVL0 RDMA0 WDMA0  MC   PP   VLD
-
-  As above, The Multimedia HW will go through SMI and M4U while it
-access EMI. SMI is a bridge between m4u and the Multimedia HW. It contain
-smi local arbiter and smi common. It will control whether the Multimedia
-HW should go though the m4u for translation or bypass it and talk
-directly with EMI. And also SMI help control the power domain and clocks for
-each local arbiter.
-  Normally we specify a local arbiter(larb) for each multimedia HW
-like display, video decode, and camera. And there are different ports
-in each larb. Take a example, There are many ports like MC, PP, VLD in the
-video decode local arbiter, all these ports are according to the video HW.
-  In some SoCs, there may be a GALS(Global Async Local Sync) module between
-smi-common and m4u, and additional GALS module between smi-larb and
-smi-common. GALS can been seen as a "asynchronous fifo" which could help
-synchronize for the modules in different clock frequency.
-
-Required properties:
-- compatible : must be one of the following string:
-	"mediatek,mt2701-m4u" for mt2701 which uses generation one m4u HW.
-	"mediatek,mt2712-m4u" for mt2712 which uses generation two m4u HW.
-	"mediatek,mt6779-m4u" for mt6779 which uses generation two m4u HW.
-	"mediatek,mt7623-m4u", "mediatek,mt2701-m4u" for mt7623 which uses
-						     generation one m4u HW.
-	"mediatek,mt8173-m4u" for mt8173 which uses generation two m4u HW.
-	"mediatek,mt8183-m4u" for mt8183 which uses generation two m4u HW.
-- reg : m4u register base and size.
-- interrupts : the interrupt of m4u.
-- clocks : must contain one entry for each clock-names.
-- clock-names : Only 1 optional clock:
-  - "bclk": the block clock of m4u.
-  Here is the list which require this "bclk":
-  - mt2701, mt2712, mt7623 and mt8173.
-  Note that m4u use the EMI clock which always has been enabled before kernel
-  if there is no this "bclk".
-- mediatek,larbs : List of phandle to the local arbiters in the current Socs.
-	Refer to bindings/memory-controllers/mediatek,smi-larb.txt. It must sort
-	according to the local arbiter index, like larb0, larb1, larb2...
-- iommu-cells : must be 1. This is the mtk_m4u_id according to the HW.
-	Specifies the mtk_m4u_id as defined in
-	dt-binding/memory/mt2701-larb-port.h for mt2701, mt7623
-	dt-binding/memory/mt2712-larb-port.h for mt2712,
-	dt-binding/memory/mt6779-larb-port.h for mt6779,
-	dt-binding/memory/mt8173-larb-port.h for mt8173, and
-	dt-binding/memory/mt8183-larb-port.h for mt8183.
-
-Example:
-	iommu: iommu@10205000 {
-		compatible = "mediatek,mt8173-m4u";
-		reg = <0 0x10205000 0 0x1000>;
-		interrupts = <GIC_SPI 139 IRQ_TYPE_LEVEL_LOW>;
-		clocks = <&infracfg CLK_INFRA_M4U>;
-		clock-names = "bclk";
-		mediatek,larbs = <&larb0 &larb1 &larb2 &larb3 &larb4 &larb5>;
-		#iommu-cells = <1>;
-	};
-
-Example for a client device:
-	display {
-		compatible = "mediatek,mt8173-disp";
-		iommus = <&iommu M4U_PORT_DISP_OVL0>,
-			 <&iommu M4U_PORT_DISP_RDMA0>;
-		...
-	};
diff --git a/Documentation/devicetree/bindings/iommu/mediatek,iommu.yaml b/Documentation/devicetree/bindings/iommu/mediatek,iommu.yaml
new file mode 100644
index 000000000000..d7b31bda3e35
--- /dev/null
+++ b/Documentation/devicetree/bindings/iommu/mediatek,iommu.yaml
@@ -0,0 +1,150 @@ 
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iommu/mediatek,iommu.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: MediaTek IOMMU Architecture Implementation
+
+maintainers:
+  - Yong Wu <yong.wu@mediatek.com>
+  - Chao Hao <chao.hao@mediatek.com>
+
+description: |+
+  Some MediaTek SOCs contain a Multimedia Memory Management Unit (M4U), and
+  this M4U have two generations of HW architecture. Generation one uses flat
+  pagetable, and only supports 4K size page mapping. Generation two uses the
+  ARM Short-Descriptor translation table format for address translation.
+
+  About the M4U Hardware Block Diagram, please check below:
+
+                EMI (External Memory Interface)
+                 |
+                m4u (Multimedia Memory Management Unit)
+                 |
+            +--------+
+            |        |
+        gals0-rx   gals1-rx    (Global Async Local Sync rx)
+            |        |
+            |        |
+        gals0-tx   gals1-tx    (Global Async Local Sync tx)
+            |        |          Some SoCs may have GALS.
+            +--------+
+                 |
+             SMI Common(Smart Multimedia Interface Common)
+                 |
+         +----------------+-------
+         |                |
+         |             gals-rx        There may be GALS in some larbs.
+         |                |
+         |                |
+         |             gals-tx
+         |                |
+     SMI larb0        SMI larb1   ... SoCs have several SMI local arbiter(larb).
+     (display)         (vdec)
+         |                |
+         |                |
+   +-----+-----+     +----+----+
+   |     |     |     |    |    |
+   |     |     |...  |    |    |  ... There are different ports in each larb.
+   |     |     |     |    |    |
+  OVL0 RDMA0 WDMA0  MC   PP   VLD
+
+  As above, The Multimedia HW will go through SMI and M4U while it
+  access EMI. SMI is a bridge between m4u and the Multimedia HW. It contain
+  smi local arbiter and smi common. It will control whether the Multimedia
+  HW should go though the m4u for translation or bypass it and talk
+  directly with EMI. And also SMI help control the power domain and clocks for
+  each local arbiter.
+
+  Normally we specify a local arbiter(larb) for each multimedia HW
+  like display, video decode, and camera. And there are different ports
+  in each larb. Take a example, There are many ports like MC, PP, VLD in the
+  video decode local arbiter, all these ports are according to the video HW.
+
+  In some SoCs, there may be a GALS(Global Async Local Sync) module between
+  smi-common and m4u, and additional GALS module between smi-larb and
+  smi-common. GALS can been seen as a "asynchronous fifo" which could help
+  synchronize for the modules in different clock frequency.
+
+properties:
+  compatible:
+    enum:
+      - mediatek,mt2701-m4u #mt2701 generation one HW
+      - mediatek,mt2712-m4u #mt2712 generation two HW
+      - mediatek,mt6779-m4u #mt6779 generation two HW
+      - mediatek,mt7623-m4u, mediatek,mt2701-m4u #mt7623 generation one HW
+      - mediatek,mt8173-m4u #mt8173 generation two HW
+      - mediatek,mt8183-m4u #mt8183 generation two HW
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  clocks:
+    description: |
+      bclk is optional. here is the list which require this bclk:
+      mt2701, mt2712, mt7623 and mt8173.
+      M4U will use the EMI clock which always has been enabled before
+      kernel if there is no this bclk.
+    items:
+      - description: bclk is the block clock.
+
+  clock-names:
+    items:
+      - const: bclk
+
+  mediatek,larbs:
+    $ref: /schemas/types.yaml#/definitions/phandle-array
+    description: |
+      List of phandle to the local arbiters in the current Socs.
+      Refer to bindings/memory-controllers/mediatek,smi-larb.yaml. It must sort
+      according to the local arbiter index, like larb0, larb1, larb2...
+
+  '#iommu-cells':
+    const: 1
+    description: |
+      This is the mtk_m4u_id according to the HW. Specifies the mtk_m4u_id as
+      defined in
+      dt-binding/memory/mt2701-larb-port.h for mt2701 and mt7623,
+      dt-binding/memory/mt2712-larb-port.h for mt2712,
+      dt-binding/memory/mt6779-larb-port.h for mt6779,
+      dt-binding/memory/mt8173-larb-port.h for mt8173,
+      dt-binding/memory/mt8183-larb-port.h for mt8183.
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - mediatek,larbs
+  - '#iommu-cells'
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/clock/mt8173-clk.h>
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+
+    iommu: iommu@10205000 {
+            compatible = "mediatek,mt8173-m4u";
+            reg = <0x10205000 0x1000>;
+            interrupts = <GIC_SPI 139 IRQ_TYPE_LEVEL_LOW>;
+            clocks = <&infracfg CLK_INFRA_M4U>;
+            clock-names = "bclk";
+            mediatek,larbs = <&larb0 &larb1 &larb2
+                              &larb3 &larb4 &larb5>;
+            #iommu-cells = <1>;
+    };
+
+  - |
+    #include <dt-bindings/memory/mt8173-larb-port.h>
+
+    /* Example for a client device */
+    display {
+           compatible = "mediatek,mt8173-disp";
+           iommus = <&iommu M4U_PORT_DISP_OVL0>,
+                    <&iommu M4U_PORT_DISP_RDMA0>;
+     };