On Tue, Jun 05, 2018 at 10:43:18PM +0100, Suzuki K Poulose wrote: > Before we update the bindings, document the current graph bindings > and usage of additional properties. > > Cc: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx> > Signed-off-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx> Reviewed-by: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx> > --- > .../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 > -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
