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Documentation: Add memory mapped ARM architected timer binding

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Add a binding for the arm architected timer hardware's memory
mapped interface. The mmio timer hardware is made up of one base
frame and a collection of up to 8 timer frames, where each of the
8 timer frames can have either one or two views. A frame
typically maps to a privilege level (user/kernel, hypervisor,
secure). The first view has full access to the registers within a
frame, while the second view can be restricted to particular
registers within a frame. Each frame must support a physical
timer. It's optional for a frame to support a virtual timer.

Cc: devicetree-discuss@lists.ozlabs.org
Cc: Marc Zyngier <Marc.Zyngier@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Rob Herring <robherring2@gmail.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
This commit is contained in:
Stephen Boyd 2013-07-18 16:59:29 -07:00 committed by Daniel Lezcano
parent 1ff99ea656
commit d53ef114cf
1 changed files with 56 additions and 3 deletions
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59
Documentation/devicetree/bindings/arm/arch_timer.txt
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@ -1,10 +1,14 @@
* ARM architected timer
ARM cores may have a per-core architected timer, which provides per-cpu timers.
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 timer is attached to a GIC to deliver its per-processor interrupts.
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.
** Timer node properties:
** CP15 Timer node properties:
- compatible : Should at least contain one of
"arm,armv7-timer"
@ -26,3 +30,52 @@ Example:
<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. Optional.
- 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";
};
};