[RFC 2/2] dt-bindings: mailbox: Add Xilinx IPI Mailbox

[Rob Herring]

On Wed, Nov 29, 2017 at 03:59:07PM -0800, Wendy Liang wrote:
> Xilinx ZynqMP IPI(Inter Processor Interrupt) is a hardware block
> in ZynqMP SoC used for the communication between various processor
> systems.
> 
> Signed-off-by: Wendy Liang <jliang at xilinx.com>
> ---
>  .../bindings/mailbox/xlnx,zynqmp-ipi-mailbox.txt   | 113 +++++++++++++++++++++
>  1 file changed, 113 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/mailbox/xlnx,zynqmp-ipi-mailbox.txt
> 
> diff --git a/Documentation/devicetree/bindings/mailbox/xlnx,zynqmp-ipi-mailbox.txt b/Documentation/devicetree/bindings/mailbox/xlnx,zynqmp-ipi-mailbox.txt
> new file mode 100644
> index 0000000..a118d00
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/mailbox/xlnx,zynqmp-ipi-mailbox.txt
> @@ -0,0 +1,113 @@
> +Xilinx IPI Mailbox Controller
> +========================================
> +
> +The Xilinx IPI(Inter Processor Interrupt) mailbox controller is to manage
> +messaging between two Xilinx Zynq UltraScale+ MPSoC IPI agents. Each IPI
> +agent owns registers used for notification and buffers for message.
> +
> +               +-------------------------------------+
> +               | Xilinx ZynqMP IPI Controller        |
> +               +-------------------------------------+
> +    +--------------------------------------------------+
> +ATF                    |                     |
> +                       |                     |
> +                       |                     |
> +    +--------------------------+             |
> +                       |                     |
> +                       |                     |
> +    +--------------------------------------------------+
> +            +------------------------------------------+
> +            |  +----------------+   +----------------+ |
> +Hardware    |  |  IPI Agent     |   |  IPI Buffers   | |
> +            |  |  Registers     |   |                | |
> +            |  |                |   |                | |
> +            |  +----------------+   +----------------+ |
> +            |                                          |
> +            | Xilinx IPI Agent Block                   |
> +            +------------------------------------------+
> +
> +
> +Controller Device Node:
> +===========================
> +Required properties:
> +--------------------
> +- compatible:		Shall be: "xlnx,zynqmp-ipi-mailbox"
> +- reg:			IPI buffers address ranges
> +- reg-names:		Names of the reg resources. It should have:
> +			* local_request_region
> +			  - IPI request msg buffer written by local and read
> +			    by remote
> +			* local_response_region
> +			  - IPI response msg buffer written by local and read
> +			    by remote
> +			* remote_request_region
> +			  - IPI request msg buffer written by remote and read
> +			    by local
> +			* remote_response_region
> +			  - IPI response msg buffer written by remote and read
> +			    by local
> +- #mbox-cells:		Shall be 1. It contains:
> +			* tx(0) or rx(1) channel
> +- xlnx-ipi-ids:		Xilinx IPI agent IDs of the two peers of the
> +			Xilinx IPI communication channel.

xlnx,ipi-ids

> +- interrupt-parent:	Phandle for the interrupt controller
> +- interrupts:		Interrupt information corresponding to the
> +			interrupt-names property.
> +
> +Optional properties:
> +--------------------
> +- method:              The method of accessing the IPI agent registers.
> +                       Permitted values are: "smc" and "hvc". Default is
> +                       "smc".
> +

> +Client Device Node:
> +===========================
> +Required properties:
> +--------------------
> +- mboxes:		Standard property to specify a mailbox
> +			(See ./mailbox.txt)
> +- mbox-names:		List of identifier  strings for each mailbox
> +			channel.

This part is a standard part of the binding and doesn't need to be here.

> +
> +Example:
> +===========================
> +	/* APU<->RPU0 IPI mailbox controller */
> +	ipi_mailbox_rpu0: mailbox at ff90400 {
> +		compatible = "xlnx,zynqmp-ipi-mailbox";
> +		reg = <0x0 0xff990400 0x0 0x20>,
> +		      <0x0 0xff990420 0x0 0x20>,
> +		      <0x0 0xff990080 0x0 0x20>,
> +		      <0x0 0xff9900a0 0x0 0x20>;
> +		reg-names = "local_request_region", "local_response_region",
> +			    "remote_request_region", "remote_response_region";
> +		#mbox-cells = <1>;
> +		xlnx-ipi-ids = <0 1>;
> +		interrupt-parent = <&gic>;
> +		interrupts = <0 29 4>;
> +	};
> +	/* APU<->RPU1 IPI mailbox controller */
> +	ipi_mailbox_rpu1: mailbox at ff990440 {
> +		compatible = "xlnx,zynqmp-ipi-mailbox";
> +		reg = <0x0 0xff990440 0x0 0x20>,
> +		      <0x0 0xff990460 0x0 0x20>,
> +		      <0x0 0xff990280 0x0 0x20>,
> +		      <0x0 0xff9902a0 0x0 0x20>;
> +		reg-names = "local_request_region", "local_response_region",
> +			    "remote_request_region", "remote_response_region";
> +		#mbox-cells = <1>;
> +		xlnx-ipi-ids = <0 2>;
> +		interrupt-parent = <&gic>;
> +		interrupts = <0 29 4>;
> +	};
> +	rpu0 {
> +		...
> +		mboxes = <&ipi_mailbox_rpu0 0>,
> +			 <&ipi_mailbox_rpu0 1>;
> +		mbox-names = "tx", "rx";
> +	};
> +	rpu1 {
> +		...
> +		mboxes = <&ipi_mailbox_rpu1 0>,
> +			 <&ipi_mailbox_rpu1 1>;
> +		mbox-names = "tx", "rx";
> +	};
> -- 
> 2.7.4
> 
> --
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