[PATCH v2 1/7] dt-bindings: arm: Add support for Coresight TGU trace
From: Songwei Chai
Date: Thu Oct 10 2024 - 04:24:24 EST
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 <quic_songchai@xxxxxxxxxxx>
---
.../bindings/arm/qcom,coresight-tgu.yaml | 133 ++++++++++++++++++
1 file changed, 133 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..25b464486fe2
--- /dev/null
+++ b/Documentation/devicetree/bindings/arm/qcom,coresight-tgu.yaml
@@ -0,0 +1,133 @@
+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+# Copyright (c) 2023 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 of the SoC.
+
+maintainers:
+ - Mao Jinlong <quic_jinlmao@xxxxxxxxxxx>
+ - Sam Chai <quic_songchai@xxxxxxxxxxx>
+
+# 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
+
+ qcom,tgu-steps:
+ description:
+ The trigger logic is realized by configuring each step after sensing
+ the signal. The parameter here is used to describe the maximum of steps
+ that could be configured in the current TGU.
+ $ref: /schemas/types.yaml#/definitions/uint32
+ minimum: 1
+ maximum: 8
+
+ qcom,tgu-regs:
+ description:
+ There are some "groups" register clusters in each step, which are used to configure the signal
+ that we want to detect.Meanwhile, each group has its own priority, and the priority increases
+ with number of groups.For example, group3 has a higher priority than group2 ,the signal configured
+ in group3 will be sensed more preferentially than the signal which is configured in group2.
+ The parameter here is used to describe the signal number that each group could be configured.
+ $ref: /schemas/types.yaml#/definitions/uint32
+ minimum: 1
+ maximum: 18
+
+ qcom,tgu-conditions:
+ description:
+ A condition sets a specific requirement for a step and defines the subsequent
+ action once the requirement is met. For example, in step two, if signal A is
+ detected three times, the process jumps back to step one. The parameter describes
+ the register number for each functionality, whether it is setting a specific
+ requirement or defining a subsequent action.
+ $ref: /schemas/types.yaml#/definitions/uint32
+ minimum: 1
+ maximum: 4
+
+ qcom,tgu-timer-counters:
+ description:
+ TGU has timer and counter which are used to set some requirement on each step.
+ For example, we could use counter to create a trigger into CTI once TGU senses
+ the target signal three times.This parameter is used to describe the number of
+ Timers/Counters in TGU.
+ $ref: /schemas/types.yaml#/definitions/uint32
+ minimum: 0
+ maximum: 2
+
+ in-ports:
+ $ref: /schemas/graph.yaml#/properties/ports
+ additionalProperties: false
+
+ properties:
+ port:
+ description: AXI Slave connected to another Coresight component
+ $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";
+
+ qcom,tgu-steps = <3>;
+ qcom,tgu-regs = <4>;
+ qcom,tgu-conditions = <4>;
+ qcom,tgu-timer-counters = <1>;
+
+ in-ports {
+ port {
+ tgu_in_tpdm_swao: endpoint{
+ remote-endpoint = <&tpdm_swao_out_tgu>;
+ };
+ };
+ };
+ };
+...