Re: [PATCH v3 3/3] dt-binding:Documents the mbigen bindings

From: Mark Rutland
Date: Wed Jul 08 2015 - 09:40:48 EST


On Mon, Jul 06, 2015 at 08:09:08AM +0100, Ma Jun wrote:
> Add the mbigen msi interrupt controller bindings document
>
> Change in v3:
> ---Change the compatible string
> ---Change the interrupt cells definition.
>
> Signed-off-by: Ma Jun <majun258@xxxxxxxxxx>
> ---
> Documentation/devicetree/bindings/arm/mbigen.txt | 65 ++++++++++++++++++++++
> 1 files changed, 65 insertions(+), 0 deletions(-)
> create mode 100644 Documentation/devicetree/bindings/arm/mbigen.txt
>
> diff --git a/Documentation/devicetree/bindings/arm/mbigen.txt b/Documentation/devicetree/bindings/arm/mbigen.txt
> new file mode 100644
> index 0000000..cf92ef8
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/arm/mbigen.txt
> @@ -0,0 +1,65 @@
> +Hisilicon mbigen device tree bindings.
> +=======================================
> +
> +Mbigen means: message based interrupt generator.
> +
> +MBI is kind of msi interrupt only used on Non-PCI devices.
> +
> +To reduce the wired interrupt number connected to GIC,
> +Hisilicon designed mbigen to collect and generate interrupt.
> +
> +
> +Non-pci devices can connect to mbigen and gnerate the inteerrupt
> +by wirtting ITS register.

Please run this through a spell checker to get rid of typos.

> +
> +The mbigen and devices connect to mbigen have the following properties:
> +
> +
> +Mbigen required properties:
> +-------------------------------------------
> +-compatible: Should be "hisilicon,mbigen-v2"
> +-msi-parent: should specified the ITS mbigen connected
> +-interrupt controller: Identifies the node as an interrupt controller
> +- #interrupt-cells : Specifies the number of cells needed to encode an
> + interrupt source. The value is 5 now.
> +
> + The 1st cell is the device id.

Does a given mbigen block generate interrupts with different ITS device
IDs? Or does a given mbigen block have a single device ID shared by all
interrupts it generates?

> + The 2nd cell is the totall interrupt number of this device?

I don't follow. What is a "total interrupt number"?

> + The 3rd cell is the hardware pin number of the interrupt.
> + This value depends on the Soc design.

This property seems sane.

> + The 4th cell is the mbigen node number. This value should refer to the
> + vendor soc specification.

What is this, and why do you think you need it?

Surely the address of the mbigen node is a sufficient unique identifier?

> + The 5th cell is the interrupt trigger type, encoded as follows:
> + 1 = edge triggered
> + 4 = level triggered

Hmm. How are level-triggered interrupts expected to be handled by the
mbigen?

> +
> +- reg: Specifies the base physical address and size of the ITS
> + registers.

NAK. You should not describe ITS properties here given this is not the
ITS.

Perhaps you mean "the mbigen registers"?

Thanks,
Mark.
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