[PATCH v5 1/7] dt-bindings: arm: Add support for Coresight TGU trace
From: Songwei Chai <hidden>
Date: 2025-05-29 08:20:20
Also in:
linux-arm-msm, linux-devicetree, lkml
Subsystem:
arm/coresight framework and drivers, arm/qualcomm mailing list, open firmware and flattened device tree bindings, the rest · Maintainers:
Suzuki K Poulose, Rob Herring, Krzysztof Kozlowski, Conor Dooley, Linus Torvalds
The Trigger Generation Unit (TGU) is designed to detect patterns or
sequences within a specific region of the System on Chip (SoC). Once
configured and activated, it monitors sense inputs and can detect a
pre-programmed state or sequence across clock cycles, subsequently
producing a trigger.
TGU configuration space
offset table
x-------------------------x
| |
| |
| | Step configuration
| | space layout
| coresight management | x-------------x
| registers | |---> | |
| | | | reserve |
| | | | |
|-------------------------| | |-------------|
| | | | priority[3] |
| step[7] |<-- | |-------------|
|-------------------------| | | | priority[2] |
| | | | |-------------|
| ... | |Steps region | | priority[1] |
| | | | |-------------|
|-------------------------| | | | priority[0] |
| |<-- | |-------------|
| step[0] |--------------------> | |
|-------------------------| | condition |
| | | |
| control and status | x-------------x
| space | | |
x-------------------------x |Timer/Counter|
| |
x-------------x
TGU Configuration in Hardware
The TGU provides a step region for user configuration, similar
to a flow chart. Each step region consists of three register clusters:
1.Priority Region: Sets the required signals with priority.
2.Condition Region: Defines specific requirements (e.g., signal A
reaches three times) and the subsequent action once the requirement is
met.
3.Timer/Counter (Optional): Provides timing or counting functionality.
Add a new coresight-tgu.yaml file to describe the bindings required to
define the TGU in the device trees.
Signed-off-by: Songwei Chai <redacted>
---
.../bindings/arm/qcom,coresight-tgu.yaml | 92 +++++++++++++++++++
1 file changed, 92 insertions(+)
create mode 100644 Documentation/devicetree/bindings/arm/qcom,coresight-tgu.yaml
diff --git a/Documentation/devicetree/bindings/arm/qcom,coresight-tgu.yaml b/Documentation/devicetree/bindings/arm/qcom,coresight-tgu.yaml
new file mode 100644
index 000000000000..3576d3871126
--- /dev/null
+++ b/Documentation/devicetree/bindings/arm/qcom,coresight-tgu.yaml@@ -0,0 +1,92 @@ +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause +# Copyright (c) 2025 Qualcomm Innovation Center, Inc. All rights reserved. +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/arm/qcom,coresight-tgu.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: Trigger Generation Unit - TGU + +description: | + The Trigger Generation Unit (TGU) is a Data Engine which can be utilized + to sense a plurality of signals and create a trigger into the CTI or + generate interrupts to processors. The TGU is like the trigger circuit + of a Logic Analyzer. The corresponding trigger logic can be realized by + configuring the conditions for each step after sensing the signal. + Once setup and enabled, it will observe sense inputs and based upon + the activity of those inputs, even over clock cycles, may detect a + preprogrammed state/sequence and then produce a trigger or interrupt. + + The primary use case of the TGU is to detect patterns or sequences on a + given set of signals within some region to indentify the issue in time + once there is abnormal behavior in the subsystem. + +maintainers: + - Mao Jinlong <quic_jinlmao@quicinc.com> + - Sam Chai <quic_songchai@quicinc.com> + +# Need a custom select here or 'arm,primecell' will match on lots of nodes +select: + properties: + compatible: + contains: + enum: + - qcom,coresight-tgu + required: + - compatible + +properties: + compatible: + items: + - const: qcom,coresight-tgu + - const: arm,primecell + + reg: + maxItems: 1 + + clocks: + maxItems: 1 + + clock-names: + items: + - const: apb_pclk + + in-ports: + $ref: /schemas/graph.yaml#/properties/ports + additionalProperties: false + + properties: + port: + description: + The port mechanism here ensures the relationship between TGU and + TPDM, as TPDM is one of the inputs for TGU. It will allow TGU to + function as TPDM's helper and enable TGU when the connected + TPDM is enabled. + $ref: /schemas/graph.yaml#/properties/port + +required: + - compatible + - reg + - clocks + - clock-names + +additionalProperties: false + +examples: + - | + tgu@10b0e000 { + compatible = "qcom,coresight-tgu", "arm,primecell"; + reg = <0x10b0e000 0x1000>; + + clocks = <&aoss_qmp>; + clock-names = "apb_pclk"; + + in-ports { + port { + tgu_in_tpdm_swao: endpoint{ + remote-endpoint = <&tpdm_swao_out_tgu>; + }; + }; + }; + }; +...