Before we updat the bindings, document the current graph bindings
and usage of additional properties.
Cc: Mathieu Poirier <mathieu.poir...@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poul...@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:
--
2.7.4
