tjh.dev
Linux kernel mirror (for testing)
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1# SPDX-License-Identifier: GPL-2.0
2%YAML 1.2
3---
4$id: http://devicetree.org/schemas/timer/arm,arch_timer_mmio.yaml#
5$schema: http://devicetree.org/meta-schemas/core.yaml#
6
7title: ARM memory mapped architected timer
8
9maintainers:
10 - Marc Zyngier <marc.zyngier@arm.com>
11 - Mark Rutland <mark.rutland@arm.com>
12
13description: |+
14 ARM cores may have a memory mapped architected timer, which provides up to 8
15 frames with a physical and optional virtual timer per frame.
16
17 The memory mapped timer is attached to a GIC to deliver its interrupts via SPIs.
18
19properties:
20 compatible:
21 items:
22 - enum:
23 - arm,armv7-timer-mem
24
25 reg:
26 maxItems: 1
27 description: The control frame base address
28
29 '#address-cells':
30 enum: [1, 2]
31
32 '#size-cells':
33 const: 1
34
35 clock-frequency:
36 description: The frequency of the main counter, in Hz. Should be present
37 only where necessary to work around broken firmware which does not configure
38 CNTFRQ on all CPUs to a uniform correct value. Use of this property is
39 strongly discouraged; fix your firmware unless absolutely impossible.
40
41 always-on:
42 type: boolean
43 description: If present, the timer is powered through an always-on power
44 domain, therefore it never loses context.
45
46 arm,cpu-registers-not-fw-configured:
47 type: boolean
48 description: Firmware does not initialize any of the generic timer CPU
49 registers, which contain their architecturally-defined reset values. Only
50 supported for 32-bit systems which follow the ARMv7 architected reset
51 values.
52
53 arm,no-tick-in-suspend:
54 type: boolean
55 description: The main counter does not tick when the system is in
56 low-power system suspend on some SoCs. This behavior does not match the
57 Architecture Reference Manual's specification that the system counter "must
58 be implemented in an always-on power domain."
59
60patternProperties:
61 '^frame@[0-9a-z]*$':
62 type: object
63 description: A timer node has up to 8 frame sub-nodes, each with the following properties.
64 properties:
65 frame-number:
66 allOf:
67 - $ref: "/schemas/types.yaml#/definitions/uint32"
68 - minimum: 0
69 maximum: 7
70
71 interrupts:
72 minItems: 1
73 maxItems: 2
74 items:
75 - description: physical timer irq
76 - description: virtual timer irq
77
78 reg :
79 minItems: 1
80 maxItems: 2
81 items:
82 - description: 1st view base address
83 - description: 2nd optional view base address
84
85 required:
86 - frame-number
87 - interrupts
88 - reg
89
90required:
91 - compatible
92 - reg
93 - '#address-cells'
94 - '#size-cells'
95
96examples:
97 - |
98 timer@f0000000 {
99 compatible = "arm,armv7-timer-mem";
100 #address-cells = <1>;
101 #size-cells = <1>;
102 ranges = <0 0xf0001000 0x1000>;
103 reg = <0xf0000000 0x1000>;
104 clock-frequency = <50000000>;
105
106 frame@0 {
107 frame-number = <0>;
108 interrupts = <0 13 0x8>,
109 <0 14 0x8>;
110 reg = <0x0000 0x1000>,
111 <0x1000 0x1000>;
112 };
113
114 frame@2000 {
115 frame-number = <1>;
116 interrupts = <0 15 0x8>;
117 reg = <0x2000 0x1000>;
118 };
119 };
120
121...