1 # SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
2 # Copyright (C) 2020 SiFive, Inc.
3 %YAML 1.2
4 ---
5 $id: http://devicetree.org/schemas/interrupt-controller/sifive,plic-1.0.0.yaml#
6 $schema: http://devicetree.org/meta-schemas/core.yaml#
7
8 title: SiFive Platform-Level Interrupt Controller (PLIC)
9
10 description:
11 SiFive SoCs and other RISC-V SoCs include an implementation of the
12 Platform-Level Interrupt Controller (PLIC) high-level specification in
13 the RISC-V Privileged Architecture specification. The PLIC connects all
14 external interrupts in the system to all hart contexts in the system, via
15 the external interrupt source in each hart.
16
17 A hart context is a privilege mode in a hardware execution thread. For example,
18 in an 4 core system with 2-way SMT, you have 8 harts and probably at least two
19 privilege modes per hart; machine mode and supervisor mode.
20
21 Each interrupt can be enabled on per-context basis. Any context can claim
22 a pending enabled interrupt and then release it once it has been handled.
23
24 Each interrupt has a configurable priority. Higher priority interrupts are
25 serviced first. Each context can specify a priority threshold. Interrupts
26 with priority below this threshold will not cause the PLIC to raise its
27 interrupt line leading to the context.
28
29 The PLIC supports both edge-triggered and level-triggered interrupts. For
30 edge-triggered interrupts, the RISC-V PLIC spec allows two responses to edges
31 seen while an interrupt handler is active; the PLIC may either queue them or
32 ignore them. In the first case, handlers are oblivious to the trigger type, so
33 it is not included in the interrupt specifier. In the second case, software
34 needs to know the trigger type, so it can reorder the interrupt flow to avoid
35 missing interrupts. This special handling is needed by at least the Renesas
36 RZ/Five SoC (AX45MP AndesCore with a NCEPLIC100) and the T-HEAD C900 PLIC.
37
38 While the RISC-V ISA doesn't specify a memory layout for the PLIC, the
39 "sifive,plic-1.0.0" device is a concrete implementation of the PLIC that
40 contains a specific memory layout, which is documented in chapter 8 of the
41 SiFive U5 Coreplex Series Manual <https://static.dev.sifive.com/U54-MC-RVCoreIP.pdf>.
42
43 The thead,c900-plic is different from sifive,plic-1.0.0 in opensbi, the
44 T-HEAD PLIC implementation requires setting a delegation bit to allow access
45 from S-mode. So add thead,c900-plic to distinguish them.
46
47 maintainers:
48 - Sagar Kadam <sagar.kadam@sifive.com>
49 - Paul Walmsley <paul.walmsley@sifive.com>
50 - Palmer Dabbelt <palmer@dabbelt.com>
51
52 properties:
53 compatible:
54 oneOf:
55 - items:
56 - enum:
57 - renesas,r9a07g043-plic
58 - const: andestech,nceplic100
59 - items:
60 - enum:
61 - sifive,fu540-c000-plic
62 - starfive,jh7100-plic
63 - canaan,k210-plic
64 - const: sifive,plic-1.0.0
65 - items:
66 - enum:
67 - allwinner,sun20i-d1-plic
68 - const: thead,c900-plic
69
70 reg:
71 maxItems: 1
72
73 '#address-cells':
74 const: 0
75
76 '#interrupt-cells': true
77
78 interrupt-controller: true
79
80 interrupts-extended:
81 minItems: 1
82 maxItems: 15872
83 description:
84 Specifies which contexts are connected to the PLIC, with "-1" specifying
85 that a context is not present. Each node pointed to should be a
86 riscv,cpu-intc node, which has a riscv node as parent.
87
88 riscv,ndev:
89 $ref: "/schemas/types.yaml#/definitions/uint32"
90 description:
91 Specifies how many external interrupts are supported by this controller.
92
93 clocks: true
94
95 power-domains: true
96
97 resets: true
98
99 required:
100 - compatible
101 - '#address-cells'
102 - '#interrupt-cells'
103 - interrupt-controller
104 - reg
105 - interrupts-extended
106 - riscv,ndev
107
108 allOf:
109 - if:
110 properties:
111 compatible:
112 contains:
113 enum:
114 - andestech,nceplic100
115 - thead,c900-plic
116
117 then:
118 properties:
119 '#interrupt-cells':
120 const: 2
121
122 else:
123 properties:
124 '#interrupt-cells':
125 const: 1
126
127 - if:
128 properties:
129 compatible:
130 contains:
131 const: renesas,r9a07g043-plic
132
133 then:
134 properties:
135 clocks:
136 maxItems: 1
137
138 power-domains:
139 maxItems: 1
140
141 resets:
142 maxItems: 1
143
144 required:
145 - clocks
146 - power-domains
147 - resets
148
149 additionalProperties: false
150
151 examples:
152 - |
153 plic: interrupt-controller@c000000 {
154 #address-cells = <0>;
155 #interrupt-cells = <1>;
156 compatible = "sifive,fu540-c000-plic", "sifive,plic-1.0.0";
157 interrupt-controller;
158 interrupts-extended = <&cpu0_intc 11>,
159 <&cpu1_intc 11>, <&cpu1_intc 9>,
160 <&cpu2_intc 11>, <&cpu2_intc 9>,
161 <&cpu3_intc 11>, <&cpu3_intc 9>,
162 <&cpu4_intc 11>, <&cpu4_intc 9>;
163 reg = <0xc000000 0x4000000>;
164 riscv,ndev = <10>;
165 };
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