Re: [RFC PATCH 1/8] dts: binding: coresight: Document graph bindings
From: Mathieu Poirier
Date: Fri Jun 01 2018 - 12:14:51 EST
On Fri, Jun 01, 2018 at 02:16:00PM +0100, Suzuki K Poulose wrote:
> Before we updat the bindings, document the current graph bindings
s/updat/update
> and usage of additional properties.
>
> Cc: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>
> Signed-off-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
> ---
> .../devicetree/bindings/arm/coresight.txt | 28 ++++++++++++++++++----
> 1 file changed, 24 insertions(+), 4 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/arm/coresight.txt b/Documentation/devicetree/bindings/arm/coresight.txt
> index 15ac8e8..bd36e40 100644
> --- a/Documentation/devicetree/bindings/arm/coresight.txt
> +++ b/Documentation/devicetree/bindings/arm/coresight.txt
> @@ -52,9 +52,7 @@ its hardware characteristcs.
> clocks the core of that coresight component. The latter clock
> is optional.
>
> - * port or ports: The representation of the component's port
> - layout using the generic DT graph presentation found in
> - "bindings/graph.txt".
> + * port or ports: see "Graph bindings for Coresight" below
>
> * Additional required properties for System Trace Macrocells (STM):
> * reg: along with the physical base address and length of the register
> @@ -71,7 +69,7 @@ its hardware characteristcs.
> AMBA markee):
> - "arm,coresight-replicator"
>
> - * port or ports: same as above.
> + * port or ports: see "Graph bindings for Coresight" below.
>
> * Optional properties for ETM/PTMs:
>
> @@ -86,6 +84,28 @@ its hardware characteristcs.
> * arm,buffer-size: size of contiguous buffer space for TMC ETR
> (embedded trace router)
>
> +Graph bindings for Coresight
> +-------------------------------
> +
> +Coresight components are interconnected to create a data path for the flow of
> +trace data generated from the "sources" to their collection points "sink". Each
Over 80 characters.
> +coresight component must describe the "input" and "output" connections.
> +The connections must be described via generic DT graph bindings as described
> +by the "bindings/graph.txt", where each "port" along with an "endpoint" component
Same here.
> +represents a hardware port and the connection.
> +
> +Since it is possible to have multiple connections for any coresight component with
And here.
> +a specific direction of data flow, each connection must define the following
> +properties to uniquely identify the connection details.
> +
> + * Direction of the data flow w.r.t the component :
> + Each input port must have the following property defined at the "endpoint"
> + for the port.
> + "slave-mode"
> +
> + * Hardware Port number at the component:
> + - The hardware port number is assumed to be the address of the "port" component.
And here.
Moveover this patches doesn't apply to my next tree.
> +
>
> Example:
>
> --
> 2.7.4
>