From 57f0f512b273f60d52568b8c6b77e17f5636edc0 Mon Sep 17 00:00:00 2001 From: André Fabian Silva Delgado Date: Wed, 5 Aug 2015 17:04:01 -0300 Subject: Initial import --- .../devicetree/bindings/arm/arch_timer.txt | 96 ++++++++++++++++++++++ 1 file changed, 96 insertions(+) create mode 100644 Documentation/devicetree/bindings/arm/arch_timer.txt (limited to 'Documentation/devicetree/bindings/arm/arch_timer.txt') diff --git a/Documentation/devicetree/bindings/arm/arch_timer.txt b/Documentation/devicetree/bindings/arm/arch_timer.txt new file mode 100644 index 000000000..e77412893 --- /dev/null +++ b/Documentation/devicetree/bindings/arm/arch_timer.txt @@ -0,0 +1,96 @@ +* ARM architected timer + +ARM cores may have a per-core architected timer, which provides per-cpu timers, +or a memory mapped architected timer, which provides up to 8 frames with a +physical and optional virtual timer per frame. + +The per-core architected timer is attached to a GIC to deliver its +per-processor interrupts via PPIs. The memory mapped timer is attached to a GIC +to deliver its interrupts via SPIs. + +** CP15 Timer node properties: + +- compatible : Should at least contain one of + "arm,armv7-timer" + "arm,armv8-timer" + +- interrupts : Interrupt list for secure, non-secure, virtual and + hypervisor timers, in that order. + +- clock-frequency : The frequency of the main counter, in Hz. Should be present + only where necessary to work around broken firmware which does not configure + CNTFRQ on all CPUs to a uniform correct value. Use of this property is + strongly discouraged; fix your firmware unless absolutely impossible. + +- always-on : a boolean property. If present, the timer is powered through an + always-on power domain, therefore it never loses context. + +** Optional properties: + +- arm,cpu-registers-not-fw-configured : Firmware does not initialize + any of the generic timer CPU registers, which contain their + architecturally-defined reset values. Only supported for 32-bit + systems which follow the ARMv7 architected reset values. + + +Example: + + timer { + compatible = "arm,cortex-a15-timer", + "arm,armv7-timer"; + interrupts = <1 13 0xf08>, + <1 14 0xf08>, + <1 11 0xf08>, + <1 10 0xf08>; + clock-frequency = <100000000>; + }; + +** Memory mapped timer node properties: + +- compatible : Should at least contain "arm,armv7-timer-mem". + +- clock-frequency : The frequency of the main counter, in Hz. Should be present + only when firmware has not configured the MMIO CNTFRQ registers. + +- reg : The control frame base address. + +Note that #address-cells, #size-cells, and ranges shall be present to ensure +the CPU can address a frame's registers. + +A timer node has up to 8 frame sub-nodes, each with the following properties: + +- frame-number: 0 to 7. + +- interrupts : Interrupt list for physical and virtual timers in that order. + The virtual timer interrupt is optional. + +- reg : The first and second view base addresses in that order. The second view + base address is optional. + +- status : "disabled" indicates the frame is not available for use. Optional. + +Example: + + timer@f0000000 { + compatible = "arm,armv7-timer-mem"; + #address-cells = <1>; + #size-cells = <1>; + ranges; + reg = <0xf0000000 0x1000>; + clock-frequency = <50000000>; + + frame@f0001000 { + frame-number = <0> + interrupts = <0 13 0x8>, + <0 14 0x8>; + reg = <0xf0001000 0x1000>, + <0xf0002000 0x1000>; + }; + + frame@f0003000 { + frame-number = <1> + interrupts = <0 15 0x8>; + reg = <0xf0003000 0x1000>; + status = "disabled"; + }; + }; -- cgit v1.2.3-54-g00ecf