0001 # SPDX-License-Identifier: GPL-2.0
0002 %YAML 1.2
0003 ---
0004 $id: http://devicetree.org/schemas/timer/arm,arch_timer.yaml#
0005 $schema: http://devicetree.org/meta-schemas/core.yaml#
0006
0007 title: ARM architected timer
0008
0009 maintainers:
0010 - Marc Zyngier <marc.zyngier@arm.com>
0011 - Mark Rutland <mark.rutland@arm.com>
0012 description: |+
0013 ARM cores may have a per-core architected timer, which provides per-cpu timers,
0014 or a memory mapped architected timer, which provides up to 8 frames with a
0015 physical and optional virtual timer per frame.
0016
0017 The per-core architected timer is attached to a GIC to deliver its
0018 per-processor interrupts via PPIs. The memory mapped timer is attached to a GIC
0019 to deliver its interrupts via SPIs.
0020
0021 properties:
0022 compatible:
0023 oneOf:
0024 - items:
0025 - enum:
0026 - arm,cortex-a15-timer
0027 - enum:
0028 - arm,armv7-timer
0029 - items:
0030 - enum:
0031 - arm,armv7-timer
0032 - items:
0033 - enum:
0034 - arm,armv8-timer
0035
0036 interrupts:
0037 minItems: 1
0038 items:
0039 - description: secure timer irq
0040 - description: non-secure timer irq
0041 - description: virtual timer irq
0042 - description: hypervisor timer irq
0043 - description: hypervisor virtual timer irq
0044
0045 interrupt-names:
0046 oneOf:
0047 - minItems: 2
0048 items:
0049 - const: phys
0050 - const: virt
0051 - const: hyp-phys
0052 - const: hyp-virt
0053 - minItems: 3
0054 items:
0055 - const: sec-phys
0056 - const: phys
0057 - const: virt
0058 - const: hyp-phys
0059 - const: hyp-virt
0060
0061 clock-frequency:
0062 description: The frequency of the main counter, in Hz. Should be present
0063 only where necessary to work around broken firmware which does not configure
0064 CNTFRQ on all CPUs to a uniform correct value. Use of this property is
0065 strongly discouraged; fix your firmware unless absolutely impossible.
0066
0067 always-on:
0068 type: boolean
0069 description: If present, the timer is powered through an always-on power
0070 domain, therefore it never loses context.
0071
0072 allwinner,erratum-unknown1:
0073 type: boolean
0074 description: Indicates the presence of an erratum found in Allwinner SoCs,
0075 where reading certain values from the counter is unreliable. This also
0076 affects writes to the tval register, due to the implicit counter read.
0077
0078 fsl,erratum-a008585:
0079 type: boolean
0080 description: Indicates the presence of QorIQ erratum A-008585, which says
0081 that reading the counter is unreliable unless the same value is returned
0082 by back-to-back reads. This also affects writes to the tval register, due
0083 to the implicit counter read.
0084
0085 hisilicon,erratum-161010101:
0086 type: boolean
0087 description: Indicates the presence of Hisilicon erratum 161010101, which
0088 says that reading the counters is unreliable in some cases, and reads may
0089 return a value 32 beyond the correct value. This also affects writes to
0090 the tval registers, due to the implicit counter read.
0091
0092 arm,cpu-registers-not-fw-configured:
0093 type: boolean
0094 description: Firmware does not initialize any of the generic timer CPU
0095 registers, which contain their architecturally-defined reset values. Only
0096 supported for 32-bit systems which follow the ARMv7 architected reset
0097 values.
0098
0099 arm,no-tick-in-suspend:
0100 type: boolean
0101 description: The main counter does not tick when the system is in
0102 low-power system suspend on some SoCs. This behavior does not match the
0103 Architecture Reference Manual's specification that the system counter "must
0104 be implemented in an always-on power domain."
0105
0106 required:
0107 - compatible
0108
0109 additionalProperties: false
0110
0111 oneOf:
0112 - required:
0113 - interrupts
0114 - required:
0115 - interrupts-extended
0116
0117 examples:
0118 - |
0119 timer {
0120 compatible = "arm,cortex-a15-timer",
0121 "arm,armv7-timer";
0122 interrupts = <1 13 0xf08>,
0123 <1 14 0xf08>,
0124 <1 11 0xf08>,
0125 <1 10 0xf08>;
0126 clock-frequency = <100000000>;
0127 };
0128
0129 ...
