Re: [PATCH 4/5] dt-bindings: remoteproc: Add documentation for ZynqMP R5 rproc bindings

[Mathieu Poirier <mathieu.poirier@linaro.org>]

On Mon, Feb 24, 2020 at 09:52:30AM -0800, Ben Levinsky wrote:
> From: Jason Wu <j.wu@xilinx.com>
> 
> Add binding for ZynqMP R5 OpenAMP.
> 
> Represent the RPU domain resources in one device node. Each RPU
> processor is a subnode of the top RPU domain node.
> 
> Signed-off-by: Jason Wu <j.wu@xilinx.com>
> Signed-off-by: Wendy Liang <jliang@xilinx.com>
> Signed-off-by: Michal Simek <michal.simek@xilinx.com>

Other than the yaml format that you've already taken care of, I have the
following comments:

> ---
>  .../remoteproc/xilinx,zynqmp-r5-remoteproc.txt     | 135 +++++++++++++++++++++
>  1 file changed, 135 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/remoteproc/xilinx,zynqmp-r5-remoteproc.txt
> 
> diff --git a/Documentation/devicetree/bindings/remoteproc/xilinx,zynqmp-r5-remoteproc.txt b/Documentation/devicetree/bindings/remoteproc/xilinx,zynqmp-r5-remoteproc.txt
> new file mode 100644
> index 0000000..ee7a515
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/remoteproc/xilinx,zynqmp-r5-remoteproc.txt
> @@ -0,0 +1,135 @@
> +Xilinx ARM Cortex A53-R5 remoteproc driver
> +==========================================
> +
> +ZynqMP family of devices use two Cortex R5 processors to help with various
> +low power / real time tasks.
> +
> +This driver requires specific ZynqMP hardware design.
> +
> +ZynqMP R5 Device Node:
> +=================================
> +A ZynqMP R5 device node is used to represent RPU domain
> +within ZynqMP SoC. This device node contains RPU processor
> +subnodes.
> +
> +Required Properties:
> +--------------------
> + - compatible : Should be "xlnx,zynqmp-r5-remoteproc-1.0"
> + - core_conf : R5 core configuration (valid string - split or lock-step)

Please describe "split" and "lock-step".  I am guessing that split means
core run independently from one another while lock-step is an smp configuration.
But event that is not clear from the implementation in patch 5.  I also assume
the property has no relevance when there is only one core.

> + - interrupts : Interrupt mapping for remoteproc IPI. It is required if the
> +                user uses the remoteproc driver with the RPMsg kernel driver.
> + - interrupt-parent : Phandle for the interrupt controller. It is required if
> +                      the user uses the remoteproc driver with the RPMsg kernel
> +                      kernel driver.

I can't find the interrupts and interrupts-parent properties under the
zynqmp-r5-remoteproc node.  But I do see them under the zynqmp_ipi node.  As
such there is a discrepancy between the above and the example.

> +
> +ZynqMP R5 Remoteproc Device Node:
> +=================================
> +A ZynqMP R5 Remoteproc device node is used to represent a RPU processor.
> +It is a subnode to the ZynqMP R5 device node. It also contains tightly
> +coupled memory subnodes.
> +
> +Required Properties:
> +--------------------
> + - pnode-id:	ZynqMP R5 processor power domain ID which will be used by
> +		ZynqMP power management unit to idetify the processor.
> +
> +Optional Properties:
> +--------------------
> + - memory-region: reserved memory which will be used by R5 processor
> +
> +
> +ZynqMP R5 Remoteproc Device Node:
> +=================================
> +A ZynqMP R5 Remoteproc device node is used to represent a RPU processor.
> +It is a subnode to the ZynqMP R5 device node.
> +
> +Required Properties:
> +--------------------
> + - pnode-id:	ZynqMP R5 processor power domain ID which will be used by
> +		ZynqMP power management unit to idetify the processor.
> +
> +Optional Properties:
> +--------------------
> + - memory-region:	reserved memory which will be used by R5 processor
> + - mboxes:		Specify tx and rx mailboxes
> + - mbox-names:		List of identifier strings for tx/rx mailbox channel.

This section is already laid out above, but this (other) one
has mboxes and mbox-names.  Please reorganise. 

> +
> +ZynqMP R5 TCM Device Node:
> +=================================
> +The ZynqMP R5 TCM device node is used to represent the TCM memory.
> +It is a subnode to the ZynqMP R5 processor.
> +
> +Required Properties:
> +--------------------
> + - reg:		TCM address range
> + - pnode-id:	TCM power domain ID
> +
> +
> +Example:
> +--------
> +	reserved-memory {
> +		#address-cells = <2>;
> +		#size-cells = <2>;
> +		ranges;
> +		/* R5 0 firmware memory in DDR */
> +		rproc_0_fw_reserved: rproc@3ed000000 {
> +			no-map;
> +			reg = <0x0 0x3ed00000 0x0 0x40000>;
> +		};
> +		/* DMA shared memory between APU and RPU */
> +		rpu0vdev0buffer: rpu0vdev0buffer@3ed400000 {
> +			compatible = "shared-dma-pool";
> +			no-map;
> +			reg = <0x0 0x3ed40000 0x0 0x100000>;
> +		};
> +	};
> +
> +	zynqmp-r5-remoteproc@0 {
> +		compatible = "xlnx,zynqmp-r5-remoteproc-1.0";
> +		core_conf = "split";
> +		#address-cells = <2>;
> +		#size-cells = <2>;
> +		ranges;
> +		r5-0: r5@0 {
> +			#address-cells = <2>;
> +			#size-cells = <2>;
> +			ranges;
> +			memory-region = <&rproc_0_fw_reserved>,
> +					<&rpu0vdev0buffer>;
> +			pnode-id = <0x7>;
> +			mboxes = <&ipi_mailbox_rpu0 0>, <&ipi_mailbox_rpu0 1>;
> +			mbox-names = "tx", "rx";
> +			tcm-a: tcm@0 {
> +				reg = <0x0 0xFFE00000 0x0 0x10000>,
> +				pnode-id = <0xf>;
> +			};
> +			tcm-b: tcm@1 {
> +				reg = <0x0 0xFFE20000 0x0 0x10000>,
> +				pnode-id = <0x10>;
> +			};
> +		};
> +	} ;
> +
> +	zynqmp_ipi {
> +		compatible = "xlnx,zynqmp-ipi-mailbox";
> +		interrupt-parent = <&gic>;
> +		interrupts = <0 29 4>;
> +		xlnx,ipi-id = <7>;
> +		#address-cells = <1>;
> +		#size-cells = <1>;
> +		ranges;
> +
> +		/* APU<->RPU0 IPI mailbox controller */
> +		ipi_mailbox_rpu0: mailbox@ff90600 {
> +			reg = <0xff990600 0x20>,
> +			      <0xff990620 0x20>,
> +			      <0xff9900c0 0x20>,
> +			      <0xff9900e0 0x20>;
> +			reg-names = "local_request_region",
> +				    "local_response_region",
> +				    "remote_request_region",
> +				    "remote_response_region";
> +			#mbox-cells = <1>;
> +			xlnx,ipi-id = <1>;
> +		};
> +	};
> -- 
> 2.7.4
>