diff mbox series

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

Message ID 1608717823-18387-7-git-send-email-anshuman.khandual@arm.com (mailing list archive)
State New, archived
Headers show
Series arm64: coresight: Enable ETE and TRBE | expand

Commit Message

Anshuman Khandual Dec. 23, 2020, 10:03 a.m. UTC 
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>
---
 Documentation/devicetree/bindings/arm/ete.txt | 41 +++++++++++++++++++++++++++
 1 file changed, 41 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/arm/ete.txt

Comments

Rob Herring Jan. 3, 2021, 5:02 p.m. UTC | #1 
On Wed, Dec 23, 2020 at 03:33:38PM +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>
> ---
>  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.

> 
> 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.

> +
> +** Optional properties:
> +- CoreSight connection graph, see bindings/arm/coresight.txt.
> +
> +** Example:
> +
> +ete_0 {
> +	compatible = "arm,embedded-trace-extension";
> +	cpu = <&cpu_0>;
> +};
> +
> +ete_1 {
> +	compatible = "arm,embedded-trace-extension";
> +	cpu = <&cpu_1>;
> +
> +	out-ports {	/* legacy CoreSight connection */
> +		port {
> +			ete1_out_port: endpoint@0 {
> +				remote-endpoint = <&funnel_in_port0>;
> +			};
> +		};
> +	};
> +};
> -- 
> 2.7.4
>
Suzuki K Poulose Jan. 4, 2021, 2:42 p.m. UTC | #2 
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@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>
>> ---
>>   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
Mathieu Poirier Jan. 4, 2021, 6:15 p.m. UTC | #3 
On Mon, Jan 04, 2021 at 02:42:08PM +0000, Suzuki K Poulose wrote:
> 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@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>
> > > ---
> > >   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).

Would it be possible to keep the CPU handle rather than moving things under the
CPU nodes?  ETMv3.x and ETMv4.x are using a handle and as Suzuki points out ETE
and ETMv4.x are sharing the same driver.  Proceeding differently for the ETE
would be terribly confusing.

> 
> That said, I am happy to move this under the CPU, if Mathieu is happy with
> the diversion.
> 
> Thanks for the review.
> 
> Suzuki
Rob Herring Jan. 4, 2021, 8:31 p.m. UTC | #4 
On Mon, Jan 4, 2021 at 11:15 AM Mathieu Poirier
<mathieu.poirier@linaro.org> wrote:
>
> On Mon, Jan 04, 2021 at 02:42:08PM +0000, Suzuki K Poulose wrote:
> > 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@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>
> > > > ---
> > > >   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).
>
> Would it be possible to keep the CPU handle rather than moving things under the
> CPU nodes?  ETMv3.x and ETMv4.x are using a handle and as Suzuki points out ETE
> and ETMv4.x are sharing the same driver.  Proceeding differently for the ETE
> would be terribly confusing.

Yeah, no problem.

Rob
diff mbox series

Patch

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.
+
+** Optional properties:
+- CoreSight connection graph, see bindings/arm/coresight.txt.
+
+** Example:
+
+ete_0 {
+	compatible = "arm,embedded-trace-extension";
+	cpu = <&cpu_0>;
+};
+
+ete_1 {
+	compatible = "arm,embedded-trace-extension";
+	cpu = <&cpu_1>;
+
+	out-ports {	/* legacy CoreSight connection */
+		port {
+			ete1_out_port: endpoint@0 {
+				remote-endpoint = <&funnel_in_port0>;
+			};
+		};
+	};
+};