linux-kernel - Re: [PATCH v3 3/5] dt-bindings: arm: Add Coresight TMC Control Unit hardware

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Message-ID: <9d9704ed-6ef8-4920-9874-29e0a815e2ba@kernel.org>
Date: Mon, 19 Aug 2024 08:25:33 +0200
From: Krzysztof Kozlowski <krzk@...nel.org>
To: JieGan <quic_jiegan@...cinc.com>, Rob Herring <robh@...nel.org>
Cc: Suzuki K Poulose <suzuki.poulose@....com>,
 Mike Leach <mike.leach@...aro.org>, James Clark <james.clark@...aro.org>,
 Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
 Maxime Coquelin <mcoquelin.stm32@...il.com>,
 Alexandre Torgue <alexandre.torgue@...s.st.com>,
 Krzysztof Kozlowski <krzk+dt@...nel.org>, Conor Dooley
 <conor+dt@...nel.org>, Bjorn Andersson <andersson@...nel.org>,
 Konrad Dybcio <konrad.dybcio@...aro.org>,
 Jinlong Mao <quic_jinlmao@...cinc.com>, coresight@...ts.linaro.org,
 linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
 devicetree@...r.kernel.org, Tingwei Zhang <quic_tingweiz@...cinc.com>,
 Yuanfang Zhang <quic_yuanfang@...cinc.com>,
 Tao Zhang <quic_taozha@...cinc.com>, Song Chai <quic_songchai@...cinc.com>,
 linux-arm-msm@...r.kernel.org, linux-stm32@...md-mailman.stormreply.com
Subject: Re: [PATCH v3 3/5] dt-bindings: arm: Add Coresight TMC Control Unit
 hardware

On 19/08/2024 03:49, JieGan wrote:
> On Sun, Aug 18, 2024 at 08:28:34AM -0600, Rob Herring wrote:
>> On Mon, Aug 12, 2024 at 10:41:39AM +0800, Jie Gan wrote:
>>> Add binding file to specify how to define a Coresight TMC
>>> Control Unit device in device tree.
>>>
>>> It is responsible for controlling the data filter function
>>> based on the source device's Trace ID for TMC ETR device.
>>> The trace data with that Trace id can get into ETR's buffer
>>> while other trace data gets ignored.
>>>
>>> Signed-off-by: Jie Gan <quic_jiegan@...cinc.com>
>>> ---
>>>  .../bindings/arm/qcom,coresight-ctcu.yaml     | 79 +++++++++++++++++++
>>>  1 file changed, 79 insertions(+)
>>>  create mode 100644 Documentation/devicetree/bindings/arm/qcom,coresight-ctcu.yaml
>>>
>>> diff --git a/Documentation/devicetree/bindings/arm/qcom,coresight-ctcu.yaml b/Documentation/devicetree/bindings/arm/qcom,coresight-ctcu.yaml
>>> new file mode 100644
>>> index 000000000000..7a9580007942
>>> --- /dev/null
>>> +++ b/Documentation/devicetree/bindings/arm/qcom,coresight-ctcu.yaml
>>> @@ -0,0 +1,79 @@
>>> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
>>> +%YAML 1.2
>>> +---
>>> +$id: http://devicetree.org/schemas/arm/qcom,coresight-ctcu.yaml#
>>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>>> +
>>> +title: CoreSight TMC Control Unit
>>> +
>>> +maintainers:
>>> +  - Yuanfang Zhang <quic_yuanfang@...cinc.com>
>>> +  - Mao Jinlong <quic_jinlmao@...cinc.com>
>>> +  - Jie Gan <quic_jiegan@...cinc.com>
>>> +
>>> +description:
>>> +  The Coresight TMC Control unit controls various Coresight behaviors.
>>> +  It works as a helper device when connected to TMC ETR device.
>>> +  It is responsible for controlling the data filter function based on
>>> +  the source device's Trace ID for TMC ETR device. The trace data with
>>> +  that Trace id can get into ETR's buffer while other trace data gets
>>> +  ignored.
>>
>> Nowhere is TMC defined.
> The Coresight TMC control unit(CTCU) connected to Coresight TMC device via replicator and
> works as a helper device to TMC device.

Did you understand the feedback or just responding with whatever to get
rid of reviewers?

> 
> The in-ports listed below illustrate their connection to TMC devices.
> 
>>
>>> +
>>> +properties:
>>> +  compatible:
>>> +    enum:
>>> +      - qcom,sa8775p-ctcu
>>> +
>>> +  reg:
>>> +    maxItems: 1
>>> +
>>> +  clocks:
>>> +    maxItems: 1
>>> +
>>> +  clock-names:
>>> +    items:
>>> +      - const: apb
>>> +
>>> +  in-ports:
>>
>> Use 'ports' unless you have both in and out ports.
> The ‘in-ports’ and ‘out-ports’ properties will be parsed by ‘of_coresight_get_port_parent’
> and their relationships to other devices will be stored in the coresight_platform_data structure.
> 
> for example:
> struct coresight_platform_data {
> 	int nr_inconns;
> 	int nr_outconns;
> 	struct coresight_connection **out_conns;
> 	struct coresight_connection **in_conns;
> };
> 
> https://elixir.bootlin.com/linux/v6.11-rc4/source/drivers/hwtracing/coresight/coresight-platform.c#L147

and? If you respond with some unrelated argument, we will respond with
the same: Use 'ports' unless you have both in and out ports.

Best regards,
Krzysztof