Re: [PATCH 06/11] dts: bindings: Document device tree bindings for ETE

From: Rob Herring <robh@kernel.org>
To: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: linux-arm-kernel@lists.infradead.org, coresight@lists.linaro.org,
	linux-kernel@vger.kernel.org,
	Mathieu Poirier <mathieu.poirier@linaro.org>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Mike Leach <mike.leach@linaro.org>,
	Linu Cherian <lcherian@marvell.com>,
	devicetree@vger.kernel.org
Subject: Re: [PATCH 06/11] dts: bindings: Document device tree bindings for ETE
Date: Sun, 3 Jan 2021 10:02:16 -0700	[thread overview]
Message-ID: <20210103170216.GA4048658@robh.at.kernel.org> (raw)
In-Reply-To: <1608717823-18387-7-git-send-email-anshuman.khandual@arm.com>

On Wed, Dec 23, 2020 at 03:33:38PM +0530, Anshuman Khandual wrote:
> From: Suzuki K Poulose <suzuki.poulose@arm.com>
> 
> Document the device tree bindings for Embedded Trace Extensions.
> ETE can be connected to legacy coresight components and thus
> could optionally contain a connection graph as described by
> the CoreSight bindings.
> 
> Cc: devicetree@vger.kernel.org
> Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
> Cc: Mike Leach <mike.leach@linaro.org>
> Cc: Rob Herring <robh@kernel.org>
> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
> Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
> ---
>  Documentation/devicetree/bindings/arm/ete.txt | 41 +++++++++++++++++++++++++++
>  1 file changed, 41 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/arm/ete.txt

Bindings are in schema format now, please convert this.

> 
> diff --git a/Documentation/devicetree/bindings/arm/ete.txt b/Documentation/devicetree/bindings/arm/ete.txt
> new file mode 100644
> index 0000000..b52b507
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/arm/ete.txt
> @@ -0,0 +1,41 @@
> +Arm Embedded Trace Extensions
> +
> +Arm Embedded Trace Extensions (ETE) is a per CPU trace component that
> +allows tracing the CPU execution. It overlaps with the CoreSight ETMv4
> +architecture and has extended support for future architecture changes.
> +The trace generated by the ETE could be stored via legacy CoreSight
> +components (e.g, TMC-ETR) or other means (e.g, using a per CPU buffer
> +Arm Trace Buffer Extension (TRBE)). Since the ETE can be connected to
> +legacy CoreSight components, a node must be listed per instance, along
> +with any optional connection graph as per the coresight bindings.
> +See bindings/arm/coresight.txt.
> +
> +** ETE Required properties:
> +
> +- compatible : should be one of:
> +	"arm,embedded-trace-extensions"
> +
> +- cpu : the CPU phandle this ETE belongs to.

If this is 1:1 with CPUs, then perhaps it should be a child node of the 
CPU nodes.

> +
> +** Optional properties:
> +- CoreSight connection graph, see bindings/arm/coresight.txt.
> +
> +** Example:
> +
> +ete_0 {
> +	compatible = "arm,embedded-trace-extension";
> +	cpu = <&cpu_0>;
> +};
> +
> +ete_1 {
> +	compatible = "arm,embedded-trace-extension";
> +	cpu = <&cpu_1>;
> +
> +	out-ports {	/* legacy CoreSight connection */
> +		port {
> +			ete1_out_port: endpoint@0 {
> +				remote-endpoint = <&funnel_in_port0>;
> +			};
> +		};
> +	};
> +};
> -- 
> 2.7.4
> 