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+# 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>
+
+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:
+ oneOf:
+ - enum:
+ - mediatek,mt2701-m4u # generation one
+ - mediatek,mt2712-m4u # generation two
+ - mediatek,mt6779-m4u # generation two
+ - mediatek,mt8167-m4u # generation two
+ - mediatek,mt8173-m4u # generation two
+ - mediatek,mt8183-m4u # generation two
+ - mediatek,mt8192-m4u # generation two
+
+ - description: mt7623 generation one
+ items:
+ - const: mediatek,mt7623-m4u
+ - const: mediatek,mt2701-m4u
+
+ reg:
+ maxItems: 1
+
+ interrupts:
+ maxItems: 1
+
+ clocks:
+ items:
+ - description: bclk is the block clock.
+
+ clock-names:
+ items:
+ - const: bclk
+
+ mediatek,larbs:
+ $ref: /schemas/types.yaml#/definitions/phandle-array
+ minItems: 1
+ maxItems: 32
+ 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/mt8167-larb-port.h for mt8167,
+ dt-binding/memory/mt8173-larb-port.h for mt8173,
+ dt-binding/memory/mt8183-larb-port.h for mt8183,
+ dt-binding/memory/mt8192-larb-port.h for mt8192.
+
+ power-domains:
+ maxItems: 1
+
+required:
+ - compatible
+ - reg
+ - interrupts
+ - mediatek,larbs
+ - '#iommu-cells'
+
+allOf:
+ - if:
+ properties:
+ compatible:
+ contains:
+ enum:
+ - mediatek,mt2701-m4u
+ - mediatek,mt2712-m4u
+ - mediatek,mt8173-m4u
+ - mediatek,mt8192-m4u
+
+ then:
+ required:
+ - clocks
+
+ - if:
+ properties:
+ compatible:
+ enum:
+ - mediatek,mt8192-m4u
+
+ then:
+ required:
+ - power-domains
+
+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>;
+ };