Before we update the bindings, document the current graph bindings and usage of additional properties.
Cc: Mathieu Poirier <[email protected]> Signed-off-by: Suzuki K Poulose <[email protected]> --- .../devicetree/bindings/arm/coresight.txt | 31 +++++++++++++++++++--- 1 file changed, 27 insertions(+), 4 deletions(-) diff --git a/Documentation/devicetree/bindings/arm/coresight.txt b/Documentation/devicetree/bindings/arm/coresight.txt index 9aa30a1..ed6b555 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: @@ -90,6 +88,31 @@ its hardware characteristcs. * arm,scatter-gather: boolean. Indicates that the TMC-ETR can safely use the SG mode on this system. +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 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 represents a hardware port and the connection. + +Since it is possible to have multiple connections for any coresight component +with 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. + + + Example: 1. Sinks -- 2.7.4
