1# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
2%YAML 1.2
3---
4$id: http://devicetree.org/schemas/iommu/mediatek,iommu.yaml#
5$schema: http://devicetree.org/meta-schemas/core.yaml#
6
7title: MediaTek IOMMU Architecture Implementation
8
9maintainers:
10  - Yong Wu <yong.wu@mediatek.com>
11
12description: |+
13  Some MediaTek SOCs contain a Multimedia Memory Management Unit (M4U), and
14  this M4U have two generations of HW architecture. Generation one uses flat
15  pagetable, and only supports 4K size page mapping. Generation two uses the
16  ARM Short-Descriptor translation table format for address translation.
17
18  About the M4U Hardware Block Diagram, please check below:
19
20                EMI (External Memory Interface)
21                 |
22                m4u (Multimedia Memory Management Unit)
23                 |
24            +--------+
25            |        |
26        gals0-rx   gals1-rx    (Global Async Local Sync rx)
27            |        |
28            |        |
29        gals0-tx   gals1-tx    (Global Async Local Sync tx)
30            |        |          Some SoCs may have GALS.
31            +--------+
32                 |
33             SMI Common(Smart Multimedia Interface Common)
34                 |
35         +----------------+-------
36         |                |
37         |             gals-rx        There may be GALS in some larbs.
38         |                |
39         |                |
40         |             gals-tx
41         |                |
42     SMI larb0        SMI larb1   ... SoCs have several SMI local arbiter(larb).
43     (display)         (vdec)
44         |                |
45         |                |
46   +-----+-----+     +----+----+
47   |     |     |     |    |    |
48   |     |     |...  |    |    |  ... There are different ports in each larb.
49   |     |     |     |    |    |
50  OVL0 RDMA0 WDMA0  MC   PP   VLD
51
52  As above, The Multimedia HW will go through SMI and M4U while it
53  access EMI. SMI is a bridge between m4u and the Multimedia HW. It contain
54  smi local arbiter and smi common. It will control whether the Multimedia
55  HW should go though the m4u for translation or bypass it and talk
56  directly with EMI. And also SMI help control the power domain and clocks for
57  each local arbiter.
58
59  Normally we specify a local arbiter(larb) for each multimedia HW
60  like display, video decode, and camera. And there are different ports
61  in each larb. Take a example, There are many ports like MC, PP, VLD in the
62  video decode local arbiter, all these ports are according to the video HW.
63
64  In some SoCs, there may be a GALS(Global Async Local Sync) module between
65  smi-common and m4u, and additional GALS module between smi-larb and
66  smi-common. GALS can been seen as a "asynchronous fifo" which could help
67  synchronize for the modules in different clock frequency.
68
69properties:
70  compatible:
71    oneOf:
72      - enum:
73          - mediatek,mt2701-m4u  # generation one
74          - mediatek,mt2712-m4u  # generation two
75          - mediatek,mt6779-m4u  # generation two
76          - mediatek,mt8167-m4u  # generation two
77          - mediatek,mt8173-m4u  # generation two
78          - mediatek,mt8183-m4u  # generation two
79          - mediatek,mt8192-m4u  # generation two
80
81      - description: mt7623 generation one
82        items:
83          - const: mediatek,mt7623-m4u
84          - const: mediatek,mt2701-m4u
85
86  reg:
87    maxItems: 1
88
89  interrupts:
90    maxItems: 1
91
92  clocks:
93    items:
94      - description: bclk is the block clock.
95
96  clock-names:
97    items:
98      - const: bclk
99
100  mediatek,larbs:
101    $ref: /schemas/types.yaml#/definitions/phandle-array
102    minItems: 1
103    maxItems: 32
104    items:
105      maxItems: 1
106    description: |
107      List of phandle to the local arbiters in the current Socs.
108      Refer to bindings/memory-controllers/mediatek,smi-larb.yaml. It must sort
109      according to the local arbiter index, like larb0, larb1, larb2...
110
111  '#iommu-cells':
112    const: 1
113    description: |
114      This is the mtk_m4u_id according to the HW. Specifies the mtk_m4u_id as
115      defined in
116      dt-binding/memory/mt2701-larb-port.h for mt2701 and mt7623,
117      dt-binding/memory/mt2712-larb-port.h for mt2712,
118      dt-binding/memory/mt6779-larb-port.h for mt6779,
119      dt-binding/memory/mt8167-larb-port.h for mt8167,
120      dt-binding/memory/mt8173-larb-port.h for mt8173,
121      dt-binding/memory/mt8183-larb-port.h for mt8183,
122      dt-binding/memory/mt8192-larb-port.h for mt8192.
123
124  power-domains:
125    maxItems: 1
126
127required:
128  - compatible
129  - reg
130  - interrupts
131  - mediatek,larbs
132  - '#iommu-cells'
133
134allOf:
135  - if:
136      properties:
137        compatible:
138          contains:
139            enum:
140              - mediatek,mt2701-m4u
141              - mediatek,mt2712-m4u
142              - mediatek,mt8173-m4u
143              - mediatek,mt8192-m4u
144
145    then:
146      required:
147        - clocks
148
149  - if:
150      properties:
151        compatible:
152          enum:
153            - mediatek,mt8192-m4u
154
155    then:
156      required:
157        - power-domains
158
159additionalProperties: false
160
161examples:
162  - |
163    #include <dt-bindings/clock/mt8173-clk.h>
164    #include <dt-bindings/interrupt-controller/arm-gic.h>
165
166    iommu: iommu@10205000 {
167            compatible = "mediatek,mt8173-m4u";
168            reg = <0x10205000 0x1000>;
169            interrupts = <GIC_SPI 139 IRQ_TYPE_LEVEL_LOW>;
170            clocks = <&infracfg CLK_INFRA_M4U>;
171            clock-names = "bclk";
172            mediatek,larbs = <&larb0>, <&larb1>, <&larb2>,
173                             <&larb3>, <&larb4>, <&larb5>;
174            #iommu-cells = <1>;
175    };
176
177  - |
178    #include <dt-bindings/memory/mt8173-larb-port.h>
179
180    /* Example for a client device */
181    display {
182           compatible = "mediatek,mt8173-disp";
183           iommus = <&iommu M4U_PORT_DISP_OVL0>,
184                    <&iommu M4U_PORT_DISP_RDMA0>;
185     };
186