[PATCH 06/11] dts: bindings: Document device tree bindings for ETE

[Suzuki K Poulose]

Hi Rob,

On 1/3/21 5:02 PM, Rob Herring wrote:
> On Wed, Dec 23, 2020 at 03:33:38PM +0530, Anshuman Khandual wrote:
>> From: Suzuki K Poulose <suzuki.poulose at 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 at vger.kernel.org
>> Cc: Mathieu Poirier <mathieu.poirier at linaro.org>
>> Cc: Mike Leach <mike.leach at linaro.org>
>> Cc: Rob Herring <robh at kernel.org>
>> Signed-off-by: Suzuki K Poulose <suzuki.poulose at arm.com>
>> Signed-off-by: Anshuman Khandual <anshuman.khandual at arm.com>
>> ---
>>   Documentation/devicetree/bindings/arm/ete.txt | 41 +++++++++++++++++++++++++++
>>   1 file changed, 41 insertions(+)
>>   create mode 100644 Documentation/devicetree/bindings/arm/ete.txt
> 
> Bindings are in schema format now, please convert this.
> 

Sure, will do that.

>>
>> diff --git a/Documentation/devicetree/bindings/arm/ete.txt b/Documentation/devicetree/bindings/arm/ete.txt
>> new file mode 100644
>> index 0000000..b52b507
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/arm/ete.txt
>> @@ -0,0 +1,41 @@
>> +Arm Embedded Trace Extensions
>> +
>> +Arm Embedded Trace Extensions (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.
>> +
>> +** ETE Required properties:
>> +
>> +- compatible : should be one of:
>> +	"arm,embedded-trace-extensions"
>> +
>> +- cpu : the CPU phandle this ETE belongs to.
> 
> If this is 1:1 with CPUs, then perhaps it should be a child node of the
> CPU nodes.

Yes, it is 1:1 with the CPUs. I have tried to keep this aligned with that of
"coresight-etm4x". The same driver handles both. The only reason why this
was separated from the "coresight.txt" is to describe the new configurations
possible (read, TRBE).

That said, I am happy to move this under the CPU, if Mathieu is happy with
the diversion.

Thanks for the review.

Suzuki