[v2,05/12] dt-bindings: remoteproc: Add Qualcomm RPM processor/subsystem

  On Qualcomm platforms, most subsystems (e.g. audio/modem DSP) are
described as remote processors in the device tree, with a dedicated
node where properties and services related to them can be described.

The Resource Power Manager (RPM) is also such a subsystem, with a
remote processor that is running a special firmware. Unfortunately,
the RPM never got a dedicated node representing it properly in the
device tree. Most of the RPM services are described below a top-level
/smd or /rpm-glink node.

However, SMD/GLINK is just one of the communication channels to the RPM
firmware. For example, the MPM interrupt functionality provided by the
RPM does not use SMD/GLINK but writes directly to a special memory
region allocated by the RPM firmware in combination with a mailbox.
Currently there is no good place in the device tree to describe this
functionality. It doesn't belong below SMD/GLINK but it's not an
independent top-level device either.

Introduce a new "qcom,rpm-proc" compatible that allows describing the
RPM as a remote processor/subsystem like all others. The SMD/GLINK node
is moved to a "smd-edge"/"glink-edge" subnode consistent with other
existing bindings. Additional subnodes (e.g. interrupt-controller for
MPM, rpm-master-stats) can be also added there.

Deprecate using the old top-level /smd node since all SMD edges
are now specified as subnodes of the remote processor.

Signed-off-by: Stephan Gerhold <stephan@gerhold.net>
---
This patch is based on qcom/for-next, since it needs the new
qcom,rpm-master-stats.yaml schema that is only applied there.
---
 .../bindings/remoteproc/qcom,rpm-proc.yaml         | 171 +++++++++++++++++++++
 .../devicetree/bindings/soc/qcom/qcom,smd-rpm.yaml |   6 +-
 .../devicetree/bindings/soc/qcom/qcom,smd.yaml     |   7 +
 3 files changed, 181 insertions(+), 3 deletions(-)
  

On Thu, 08 Jun 2023 09:10:25 +0200, Stephan Gerhold wrote:
> On Qualcomm platforms, most subsystems (e.g. audio/modem DSP) are
> described as remote processors in the device tree, with a dedicated
> node where properties and services related to them can be described.
> 
> The Resource Power Manager (RPM) is also such a subsystem, with a
> remote processor that is running a special firmware. Unfortunately,
> the RPM never got a dedicated node representing it properly in the
> device tree. Most of the RPM services are described below a top-level
> /smd or /rpm-glink node.
> 
> However, SMD/GLINK is just one of the communication channels to the RPM
> firmware. For example, the MPM interrupt functionality provided by the
> RPM does not use SMD/GLINK but writes directly to a special memory
> region allocated by the RPM firmware in combination with a mailbox.
> Currently there is no good place in the device tree to describe this
> functionality. It doesn't belong below SMD/GLINK but it's not an
> independent top-level device either.
> 
> Introduce a new "qcom,rpm-proc" compatible that allows describing the
> RPM as a remote processor/subsystem like all others. The SMD/GLINK node
> is moved to a "smd-edge"/"glink-edge" subnode consistent with other
> existing bindings. Additional subnodes (e.g. interrupt-controller for
> MPM, rpm-master-stats) can be also added there.
> 
> Deprecate using the old top-level /smd node since all SMD edges
> are now specified as subnodes of the remote processor.
> 
> Signed-off-by: Stephan Gerhold <stephan@gerhold.net>
> ---
> This patch is based on qcom/for-next, since it needs the new
> qcom,rpm-master-stats.yaml schema that is only applied there.
> ---
>  .../bindings/remoteproc/qcom,rpm-proc.yaml         | 171 +++++++++++++++++++++
>  .../devicetree/bindings/soc/qcom/qcom,smd-rpm.yaml |   6 +-
>  .../devicetree/bindings/soc/qcom/qcom,smd.yaml     |   7 +
>  3 files changed, 181 insertions(+), 3 deletions(-)
> 

My bot found errors running 'make DT_CHECKER_FLAGS=-m dt_binding_check'
on your patch (DT_CHECKER_FLAGS is new in v5.13):

yamllint warnings/errors:

dtschema/dtc warnings/errors:
./Documentation/devicetree/bindings/remoteproc/qcom,rpm-proc.yaml: Unable to find schema file matching $id: http://devicetree.org/schemas/soc/qcom/qcom,rpm-master-stats.yaml

doc reference errors (make refcheckdocs):

See https://patchwork.ozlabs.org/project/devicetree-bindings/patch/20230531-rpm-rproc-v2-5-56a4a00c8260@gerhold.net

The base for the series is generally the latest rc1. A different dependency
should be noted in *this* patch.

If you already ran 'make dt_binding_check' and didn't see the above
error(s), then make sure 'yamllint' is installed and dt-schema is up to
date:

pip3 install dtschema --upgrade

Please check and re-submit after running the above command yourself. Note
that DT_SCHEMA_FILES can be set to your schema file to speed up checking
your schema. However, it must be unset to test all examples with your schema.
  

On 08/06/2023 09:10, Stephan Gerhold wrote:
> On Qualcomm platforms, most subsystems (e.g. audio/modem DSP) are
> described as remote processors in the device tree, with a dedicated
> node where properties and services related to them can be described.


Thank you for your patch. There is something to discuss/improve.


> +
> +  smd-edge:
> +    $ref: /schemas/remoteproc/qcom,smd-edge.yaml#
> +    description:
> +      Qualcomm Shared Memory subnode which represents communication edge,
> +      channels and devices related to the RPM subsystem.
> +
> +  glink-rpm:

This should be "glink-edge", to be a bit more generic and match existing
smd-edge.

> +    $ref: /schemas/remoteproc/qcom,glink-rpm-edge.yaml#
> +    description:
> +      Qualcomm G-Link subnode which represents communication edge,
> +      channels and devices related to the RPM subsystem.
> +
> +  interrupt-controller:
> +    type: object
> +    $ref: /schemas/interrupt-controller/qcom,mpm.yaml#
> +    description:
> +      MSM Power Manager (MPM) interrupt controller that monitors interrupts
> +      when the system is asleep.
> +
> +  master-stats:
> +    $ref: /schemas/soc/qcom/qcom,rpm-master-stats.yaml#
> +    description:
> +      Subsystem-level low-power mode statistics provided by RPM.
> +
> +required:
> +  - compatible
> +


Best regards,
Krzysztof
  

On Sat, Jun 10, 2023 at 06:43:17PM +0200, Krzysztof Kozlowski wrote:
> On 08/06/2023 09:10, Stephan Gerhold wrote:
> > On Qualcomm platforms, most subsystems (e.g. audio/modem DSP) are
> > described as remote processors in the device tree, with a dedicated
> > node where properties and services related to them can be described.
> > +
> > +  smd-edge:
> > +    $ref: /schemas/remoteproc/qcom,smd-edge.yaml#
> > +    description:
> > +      Qualcomm Shared Memory subnode which represents communication edge,
> > +      channels and devices related to the RPM subsystem.
> > +
> > +  glink-rpm:
> 
> This should be "glink-edge", to be a bit more generic and match existing
> smd-edge.
> 

I fully agree and I actually made that change at some point before
sending v1. Unfortunately, it doesn't work: The node name "glink-edge"
is already reserved by qcom,glink-edge.yaml. While it's very similar it
has some subtle differences to glink-rpm-edge.yaml. For example, there
is no qcom,remote-pid in the RPM variant which is required by the normal
glink-edge.

Would "glink-rpm-edge" sound better?

Thanks,
Stephan
  

On 10/06/2023 18:52, Stephan Gerhold wrote:
> On Sat, Jun 10, 2023 at 06:43:17PM +0200, Krzysztof Kozlowski wrote:
>> On 08/06/2023 09:10, Stephan Gerhold wrote:
>>> On Qualcomm platforms, most subsystems (e.g. audio/modem DSP) are
>>> described as remote processors in the device tree, with a dedicated
>>> node where properties and services related to them can be described.
>>> +
>>> +  smd-edge:
>>> +    $ref: /schemas/remoteproc/qcom,smd-edge.yaml#
>>> +    description:
>>> +      Qualcomm Shared Memory subnode which represents communication edge,
>>> +      channels and devices related to the RPM subsystem.
>>> +
>>> +  glink-rpm:
>>
>> This should be "glink-edge", to be a bit more generic and match existing
>> smd-edge.
>>
> 
> I fully agree and I actually made that change at some point before
> sending v1. Unfortunately, it doesn't work: The node name "glink-edge"
> is already reserved by qcom,glink-edge.yaml. While it's very similar it
> has some subtle differences to glink-rpm-edge.yaml. For example, there
> is no qcom,remote-pid in the RPM variant which is required by the normal
> glink-edge.

But the other variant has, so they are pretty similar. It could be one
binding or some common part. Anyway we can as well drop the nodename
from the qcom,glink-edge.yaml binding. Anyway the binding is referenced
by each specific remote proc, so this nodename brings nothing.

> Would "glink-rpm-edge" sound better?
> 
> Thanks,
> Stephan
> 

Best regards,
Krzysztof