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 $schema: http://devicetree.org/meta-schemas/core.yaml#
6
7 title: ARM memory mapped architected timer
8
9 maintainers:
10 - Marc Zyngier <marc.zyngier@arm.com>
11 - Mark Rutland <mark.rutland@arm.com>
12
13 description: |+
14 ARM cores may have a memory mapped architected timer, which provides up to 8
15 frames with a physical and optional virtual timer per frame.
16
17 The memory mapped timer is attached to a GIC to deliver its interrupts via SPIs.
18
19 properties:
20 compatible:
21 items:
22 - enum:
23 - arm,armv7-timer-mem
24
25 reg:
26 maxItems: 1
27 description: The control frame base address
28
29 '#address-cells':
30 enum: [1, 2]
31
32 '#size-cells':
33 const: 1
34
35 ranges: true
36
37 clock-frequency:
38 description: The frequency of the main counter, in Hz. Should be present
39 only where necessary to work around broken firmware which does not configure
40 CNTFRQ on all CPUs to a uniform correct value. Use of this property is
41 strongly discouraged; fix your firmware unless absolutely impossible.
42
43 always-on:
44 type: boolean
45 description: If present, the timer is powered through an always-on power
46 domain, therefore it never loses context.
47
48 arm,cpu-registers-not-fw-configured:
49 type: boolean
50 description: Firmware does not initialize any of the generic timer CPU
51 registers, which contain their architecturally-defined reset values. Only
52 supported for 32-bit systems which follow the ARMv7 architected reset
53 values.
54
55 arm,no-tick-in-suspend:
56 type: boolean
57 description: The main counter does not tick when the system is in
58 low-power system suspend on some SoCs. This behavior does not match the
59 Architecture Reference Manual's specification that the system counter "must
60 be implemented in an always-on power domain."
61
62 patternProperties:
63 '^frame@[0-9a-z]*$':
64 type: object
65 description: A timer node has up to 8 frame sub-nodes, each with the following properties.
66 properties:
67 frame-number:
68 $ref: "/schemas/types.yaml#/definitions/uint32"
69 minimum: 0
70 maximum: 7
71
72 interrupts:
73 minItems: 1
74 items:
75 - description: physical timer irq
76 - description: virtual timer irq
77
78 reg:
79 minItems: 1
80 items:
81 - description: 1st view base address
82 - description: 2nd optional view base address
83
84 required:
85 - frame-number
86 - interrupts
87 - reg
88
89 required:
90 - compatible
91 - reg
92 - '#address-cells'
93 - '#size-cells'
94
95 additionalProperties: false
96
97 examples:
98 - |
99 timer@f0000000 {
100 compatible = "arm,armv7-timer-mem";
101 #address-cells = <1>;
102 #size-cells = <1>;
103 ranges = <0 0xf0001000 0x1000>;
104 reg = <0xf0000000 0x1000>;
105 clock-frequency = <50000000>;
106
107 frame@0 {
108 frame-number = <0>;
109 interrupts = <0 13 0x8>,
110 <0 14 0x8>;
111 reg = <0x0000 0x1000>,
112 <0x1000 0x1000>;
113 };
114
115 frame@2000 {
116 frame-number = <1>;
117 interrupts = <0 15 0x8>;
118 reg = <0x2000 0x1000>;
119 };
120 };
121
122 ...
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