[PATCH v2 08/10] coresight: dts: Document usage of graph bindings
From: suzuki.poulose@arm.com (Suzuki K Poulose)
Date: 2018-07-19 10:56:02
Also in:
linux-devicetree, lkml
Subsystem:
open firmware and flattened device tree bindings, the rest · Maintainers:
Rob Herring, Krzysztof Kozlowski, Conor Dooley, Linus Torvalds
Before we update the bindings, document the current graph bindings and usage of additional properties. Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> --- .../devicetree/bindings/arm/coresight.txt | 30 +++++++++++++++++++--- 1 file changed, 26 insertions(+), 4 deletions(-)
diff --git a/Documentation/devicetree/bindings/arm/coresight.txt b/Documentation/devicetree/bindings/arm/coresight.txt
index 5d1ad09..8e21512 100644
--- a/Documentation/devicetree/bindings/arm/coresight.txt
+++ b/Documentation/devicetree/bindings/arm/coresight.txt@@ -54,9 +54,7 @@ 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
@@ -73,7 +71,7 @@ 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:
@@ -96,6 +94,30 @@ its hardware characteristcs. * interrupts : Exactly one SPI may be listed for reporting the address error +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
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2.7.4