Hi Rob
On 2/9/21 7:00 PM, Rob Herring wrote:
On Wed, Jan 27, 2021 at 02:25:30PM +0530, Anshuman Khandual wrote:
From: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
Document the device tree bindings for Embedded Trace Extensions.
ETE can be connected to legacy coresight components and thus
could optionally contain a connection graph as described by
the CoreSight bindings.
Cc: devicetree@xxxxxxxxxxxxxxx
Cc: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>
Cc: Mike Leach <mike.leach@xxxxxxxxxx>
Cc: Rob Herring <robh@xxxxxxxxxx>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
Signed-off-by: Anshuman Khandual <anshuman.khandual@xxxxxxx>
---
Changes in V3:
- Fixed all DT yaml semantics problems
Documentation/devicetree/bindings/arm/ete.yaml | 74 ++++++++++++++++++++++++++
1 file changed, 74 insertions(+)
create mode 100644 Documentation/devicetree/bindings/arm/ete.yaml
diff --git a/Documentation/devicetree/bindings/arm/ete.yaml b/Documentation/devicetree/bindings/arm/ete.yaml
new file mode 100644
index 0000000..edc1fe2
--- /dev/null
+++ b/Documentation/devicetree/bindings/arm/ete.yaml
@@ -0,0 +1,74 @@
+# SPDX-License-Identifier: GPL-2.0-only or BSD-2-Clause
+# Copyright 2021, Arm Ltd
+%YAML 1.2
+---
+$id: "http://devicetree.org/schemas/arm/ete.yaml#";
+$schema: "http://devicetree.org/meta-schemas/core.yaml#";
+
+title: ARM Embedded Trace Extensions
+
+maintainers:
+ - Suzuki K Poulose <suzuki.poulose@xxxxxxx>
+ - Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>
+
+description: |
+ Arm Embedded Trace Extension(ETE) is a per CPU trace component that
+ allows tracing the CPU execution. It overlaps with the CoreSight ETMv4
+ architecture and has extended support for future architecture changes.
+ The trace generated by the ETE could be stored via legacy CoreSight
+ components (e.g, TMC-ETR) or other means (e.g, using a per CPU buffer
+ Arm Trace Buffer Extension (TRBE)). Since the ETE can be connected to
+ legacy CoreSight components, a node must be listed per instance, along
+ with any optional connection graph as per the coresight bindings.
+ See bindings/arm/coresight.txt.
+
+properties:
+ $nodename:
+ pattern: "^ete([0-9a-f]+)$"
+ compatible:
+ items:
+ - const: arm,embedded-trace-extension
+
+ cpu:
We've already established 'cpus' for this purpose.
Please see : https://lkml.kernel.org/r/9417218b-6eda-373b-a2cb-869089ffc7cd@xxxxxxx
for my response in the previous version to this and the one with out-ports.
+ description: |
+ Handle to the cpu this ETE is bound to.
+ $ref: /schemas/types.yaml#/definitions/phandle
+
+ out-ports:
+ type: object
Replace with: $ref: /schemas/graph.yaml#/properties/ports
So, just to confirm again :
The CoreSight graph bindings expect the input ports and output ports
grouped under in-ports{} and out-ports{} respectively to avoid having
to specify the direction of the ports in the individual "port" nodes.
i.e
in-ports {
property: ports
OR
property: port
required:
OneOf:
ports
port
}
out-ports {
# same as above
}
So thats why I added out-ports as a new object, where the ports/port
could be a child node.
Ideally the definition of out-ports /in-ports should go to a common schema
for CoreSight bindings, when we move to Yaml for the existing bindings,
which will follow in a separate series, later.
+ description: |
+ Output connections from the ETE to legacy CoreSight trace bus.
+ properties:
+ port:
+ $ref: /schemas/graph.yaml#/properties/port
Actually, if only 1 port ever, you can drop 'out-ports' and just have
'port'. Not sure though if the coresight stuff depends on 'out-ports'.
Cheers
Suzuki
