Before we updat the bindings, document the current graph bindings and usage of additional properties.
Cc: Mathieu Poirier mathieu.poirier@linaro.org Signed-off-by: Suzuki K Poulose suzuki.poulose@arm.com --- .../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 +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: