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@arm.com
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@vger.kernel.org Cc: Mathieu Poirier mathieu.poirier@linaro.org Cc: Mike Leach mike.leach@linaro.org Cc: Rob Herring robh@kernel.org Signed-off-by: Suzuki K Poulose suzuki.poulose@arm.com Signed-off-by: Anshuman Khandual anshuman.khandual@arm.com
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@arm.com
- Mathieu Poirier mathieu.poirier@linaro.org
+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@arm.com 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/portActually, 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