Subject: Re: [PATCH] Add device file bindings for MAPLE

From: Scott Wood <[email-masked]>
Date: Mon, 29 Jul 2013 19:00:51 -0500

On 07/27/2013 08:03:42 AM, Shaveta Leekha wrote:
> Signed-off-by: Shaveta Leekha <[email-masked]>
> ---
>  .../devicetree/bindings/powerpc/fsl/maple.txt      |   50 =20
> ++++++++++++++++++++
>  1 files changed, 50 insertions(+), 0 deletions(-)
>  create mode 100644 =20
> Documentation/devicetree/bindings/powerpc/fsl/maple.txt
>=20
> diff --git a/Documentation/devicetree/bindings/powerpc/fsl/maple.txt =20
> b/Documentation/devicetree/bindings/powerpc/fsl/maple.txt
> new file mode 100644
> index 0000000..23b80a7
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/powerpc/fsl/maple.txt
> @@ -0,0 +1,50 @@
> +* Freescale MAPLE Multi Accelerator Platform Engine Baseband 3
> +  (MAPLE-B3)device nodes
> +
> +Supported chips:
> +Example: B4860
> +
> +Required properties:
> +
> +- compatible:	Should contain "fsl,maple-b3" as the value
> +		This identifies Multi Accelerator Platform Engine
> +		Baseband 3 block.
> +
> +- reg:		offset and length of the register set for the =20
> device
> +
> +- interrupts
> +	Usage: required
> +	Value type: <prop_encoded-array>
> +	Definition:  Specifies the interrupts generated by this =20
> device.  The
> +			value of the interrupts property consists of =20
> one interrupt
> +			specifier. The format of the specifier is =20
> defined by the
> +			binding document describing the node's =20
> interrupt parent.

Please clean up whitespace so the text aligns.

> +
> +		A single IRQ that handles error conditions is specified =20
> by
> +		this property.  (Typically shared with port-write).
> +
> +Devices that have LIODNs need to specify links to the parent PAMU =20
> controller
> +(the actual PAMU controller that this device is connected to) and a =20
> pointer to
> +the LIODN register, if applicable.
> +
> +- fsl,iommu-parent
> +		: <phandle>
> +		This property should be present
> +
> +- status =3D "disabled"
> +		In this example, status is set "disabled",
> +		As Maple device wouldn't be used by PPC Linux. This =20
> representation is required
> +		for doing the PAMU programming on the Linux side.

Is it proper for Linux to even set the LIODN on a device that is =20
"disabled"?  Perhaps the compatible should be different, such as =20
"fsl,maple-b3-liodn" to indicate that that is the only portion of the =20
device that is owned by this partition.

> +Example:
> +	/* B4860 */
> +
> +	maple@800000 {
> +		#address-cells =3D <0>;
> +		#size-cells =3D <0>;
> +		status =3D "disabled";
> +		compatible =3D "fsl,maple-b3";
> +		reg =3D <0x8000000 0x10000>;
> +		interrupts =3D <16 2 1 18>;
> +		fsl,iommu-parent =3D <&pamu1>;
> +	};

This error interrupt is documented as 13, not 18.  b4860 (and maybe =20
other b4?) have an erratum that says that error interrupts are =20
reversed, but this is generally implemented in b4si-post.dtsi, not in =20
block-specific include files.  Will no chip without the erratum ever =20
have maple?

-Scott=