Subject: [PATCH v4 03/20] arm64: GICv3 device tree binding documentation

From: [email-masked] (Andre Przywara)
Date: Tue, 20 May 2014 16:58:38 +0200

On 05/15/2014 07:58 PM, Marc Zyngier wrote:
> Add the necessary documentation to support GICv3.
>
> Cc: Thomas Gleixner <[email-masked]>
> Cc: Mark Rutland <[email-masked]>
> Acked-by: Catalin Marinas <[email-masked]>
> Acked-by: Rob Herring <[email-masked]>
> Acked-by: Christoffer Dall <[email-masked]>
> Signed-off-by: Marc Zyngier <[email-masked]>
> ---
>  Documentation/devicetree/bindings/arm/gic-v3.txt | 79 ++++++++++++++++++++++++
>  1 file changed, 79 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/arm/gic-v3.txt
>
> diff --git a/Documentation/devicetree/bindings/arm/gic-v3.txt b/Documentation/devicetree/bindings/arm/gic-v3.txt
> new file mode 100644
> index 0000000..33cd05e
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/arm/gic-v3.txt
> @@ -0,0 +1,79 @@
> +* ARM Generic Interrupt Controller, version 3
> +
> +AArch64 SMP cores are often associated with a GICv3, providing Private
> +Peripheral Interrupts (PPI), Shared Peripheral Interrupts (SPI),
> +Software Generated Interrupts (SGI), and Locality-specific Peripheral
> +Interrupts (LPI).
> +
> +Main node required properties:
> +
> +- compatible : should at least contain  "arm,gic-v3".
> +- interrupt-controller : Identifies the node as an interrupt controller
> +- #interrupt-cells : Specifies the number of cells needed to encode an
> +  interrupt source. Must be a single cell with a value of at least 3.
> +
> +  The 1st cell is the interrupt type; 0 for SPI interrupts, 1 for PPI
> +  interrupts. Other values are reserved for future use.
> +
> +  The 2nd cell contains the interrupt number for the interrupt type.
> +  SPI interrupts are in the range [0-987]. PPI interrupts are in the
> +  range [0-15].
> +
> +  The 3rd cell is the flags, encoded as follows:
> +     bits[3:0] trigger type and level flags.
> +             1 = edge triggered
> +             4 = level triggered
> +
> +  Cells 4 and beyond are reserved for future use. When the 1st cell
> +  has a value of 0 or 1, cells 4 and beyond act as padding, and may be
> +  ignored. It is recommended that padding cells have a value of 0.
> +
> +- reg : Specifies base physical address(s) and size of the GIC
> +  registers, in the following order:
> +  - GIC Distributor interface (GICD)
> +  - GIC Redistributors (GICR), one range per redistributor region
> +  - GIC CPU interface (GICC)
> +  - GIC Hypervisor interface (GICH)
> +  - GIC Virtual CPU interface (GICV)
> +
> +  GICC, GICH and GICV are optional.

I wonder if it should be noted here that a lack of these last three
regions denies GICv2 emulation support for KVM guests.
It's probably not worth to introduce a special property for this v2
compat support, but if the lack of these registers is indicating that
fact, it should be added here.

Regards,
Andre.

> +
> +- interrupts : Interrupt source of the VGIC maintenance interrupt.
> +
> +Optional
> +
> +- redistributor-stride : If using padding pages, specifies the stride
> +  of consecutive redistributors. Must be a multiple of 64kB.
> +
> +- #redistributor-regions: The number of independent contiguous regions
> +  occupied by the redistributors. Required if more than one such
> +  region is present.
> +
> +Examples:
> +
> +     gic: interrupt-controller at 2cf00000 {
> +             compatible = "arm,gic-v3";
> +             #interrupt-cells = <3>;
> +             interrupt-controller;
> +             reg = <0x0 0x2f000000 0 0x10000>,       // GICD
> +                   <0x0 0x2f100000 0 0x200000>,      // GICR
> +                   <0x0 0x2c000000 0 0x2000>,        // GICC
> +                   <0x0 0x2c010000 0 0x2000>,        // GICH
> +                   <0x0 0x2c020000 0 0x2000>;        // GICV
> +             interrupts = <1 9 4>;
> +     };
> +
> +     gic: interrupt-controller at 2c010000 {
> +             compatible = "arm,gic-v3";
> +             #interrupt-cells = <3>;
> +             interrupt-controller;
> +             redistributor-stride = <0x0 0x40000>;   // 256kB stride
> +             #redistributor-regions = <2>;
> +             reg = <0x0 0x2c010000 0 0x10000>,       // GICD
> +                   <0x0 0x2d000000 0 0x800000>,      // GICR 1: CPUs 0-31
> +                   <0x0 0x2e000000 0 0x800000>;      // GICR 2: CPUs 32-63
> +                   <0x0 0x2c040000 0 0x2000>,        // GICC
> +                   <0x0 0x2c060000 0 0x2000>,        // GICH
> +                   <0x0 0x2c080000 0 0x2000>;        // GICV
> +             interrupts = <1 9 4>;
> +     };
>

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