[PATCH v4 4/8] dt-bindings: firmware: arm,scmi: Add atomic-threshold-us optional property

[PATCH v4 4/8] dt-bindings: firmware: arm,scmi: Add atomic-threshold-us optional property

[Cristian Marussi]

SCMI protocols in the platform can optionally signal to the OSPM agent
the expected execution latency for a specific resource/operation pair.

Introduce an SCMI system wide optional property to describe a global time
threshold which can be configured on a per-platform base to determine the
opportunity, or not, for an SCMI command advertised to have a higher
latency than the threshold, to be considered for atomic operations:
high-latency SCMI synchronous commands should be preferably issued in the
usual non-atomic mode.

Cc: Rob Herring <robh+dt@kernel.org>
Cc: devicetree@vger.kernel.org
Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
---
v3 --> v4
- renamed property to atomic-threshold-us
v1 --> v2
- rephrased the property description
---
 .../devicetree/bindings/firmware/arm,scmi.yaml        | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/Documentation/devicetree/bindings/firmware/arm,scmi.yaml b/Documentation/devicetree/bindings/firmware/arm,scmi.yaml
index eae15df36eef..3ffa669b91af 100644
--- a/Documentation/devicetree/bindings/firmware/arm,scmi.yaml
+++ b/Documentation/devicetree/bindings/firmware/arm,scmi.yaml
@@ -81,6 +81,15 @@ properties:
   '#size-cells':
     const: 0
 
+  atomic-threshold-us:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description:
+      An optional time value, expressed in microseconds, representing, on this
+      platform, the threshold above which any SCMI command, advertised to have
+      an higher-than-threshold execution latency, should not be considered for
+      atomic mode of operation, even if requested.
+      If left unconfigured defaults to zero.
+
   arm,smc-id:
     $ref: /schemas/types.yaml#/definitions/uint32
     description:
@@ -264,6 +273,8 @@ examples:
             #address-cells = <1>;
             #size-cells = <0>;
 
+            atomic_threshold = <10000>;
+
             scmi_devpd: protocol@11 {
                 reg = <0x11>;
                 #power-domain-cells = <1>;
-- 
2.17.1

Re: [PATCH v4 4/8] dt-bindings: firmware: arm,scmi: Add atomic-threshold-us optional property

[Cristian Marussi]

On Sun, Feb 13, 2022 at 07:58:28PM +0000, Cristian Marussi wrote:
> SCMI protocols in the platform can optionally signal to the OSPM agent
> the expected execution latency for a specific resource/operation pair.
> 
> Introduce an SCMI system wide optional property to describe a global time
> threshold which can be configured on a per-platform base to determine the
> opportunity, or not, for an SCMI command advertised to have a higher
> latency than the threshold, to be considered for atomic operations:
> high-latency SCMI synchronous commands should be preferably issued in the
> usual non-atomic mode.
> 
> Cc: Rob Herring <robh+dt@kernel.org>
> Cc: devicetree@vger.kernel.org
> Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
> ---
> v3 --> v4
> - renamed property to atomic-threshold-us
> v1 --> v2
> - rephrased the property description
> ---
>  .../devicetree/bindings/firmware/arm,scmi.yaml        | 11 +++++++++++
>  1 file changed, 11 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/firmware/arm,scmi.yaml b/Documentation/devicetree/bindings/firmware/arm,scmi.yaml
> index eae15df36eef..3ffa669b91af 100644
> --- a/Documentation/devicetree/bindings/firmware/arm,scmi.yaml
> +++ b/Documentation/devicetree/bindings/firmware/arm,scmi.yaml
> @@ -81,6 +81,15 @@ properties:
>    '#size-cells':
>      const: 0
>  

Hi Rob,

gentle ping ... any feedback on this SCMI DT addition ?

(beside the brain-dead error of mine down below in the example still
to be fixed...my bad)

> +  atomic-threshold-us:
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +    description:
> +      An optional time value, expressed in microseconds, representing, on this
> +      platform, the threshold above which any SCMI command, advertised to have
> +      an higher-than-threshold execution latency, should not be considered for
> +      atomic mode of operation, even if requested.
> +      If left unconfigured defaults to zero.
> +
>    arm,smc-id:
>      $ref: /schemas/types.yaml#/definitions/uint32
>      description:
> @@ -264,6 +273,8 @@ examples:
>              #address-cells = <1>;
>              #size-cells = <0>;
>  
> +            atomic_threshold = <10000>;
> +

...this example clearly still needs to be renamed to 'atomic-threshold-us'

Thanks,
Cristian

Re: [PATCH v4 4/8] dt-bindings: firmware: arm,scmi: Add atomic-threshold-us optional property

[Rob Herring]

On Sun, 13 Feb 2022 19:58:28 +0000, Cristian Marussi wrote:
> SCMI protocols in the platform can optionally signal to the OSPM agent
> the expected execution latency for a specific resource/operation pair.
> 
> Introduce an SCMI system wide optional property to describe a global time
> threshold which can be configured on a per-platform base to determine the
> opportunity, or not, for an SCMI command advertised to have a higher
> latency than the threshold, to be considered for atomic operations:
> high-latency SCMI synchronous commands should be preferably issued in the
> usual non-atomic mode.
> 
> Cc: Rob Herring <robh+dt@kernel.org>
> Cc: devicetree@vger.kernel.org
> Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
> ---
> v3 --> v4
> - renamed property to atomic-threshold-us
> v1 --> v2
> - rephrased the property description
> ---
>  .../devicetree/bindings/firmware/arm,scmi.yaml        | 11 +++++++++++
>  1 file changed, 11 insertions(+)
> 

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:
/builds/robherring/linux-dt-review/Documentation/devicetree/bindings/firmware/arm,scmi.yaml: properties:atomic-threshold-us: '$ref' should not be valid under {'const': '$ref'}
	hint: Standard unit suffix properties don't need a type $ref
	from schema $id: http://devicetree.org/meta-schemas/core.yaml#
/builds/robherring/linux-dt-review/Documentation/devicetree/bindings/firmware/arm,scmi.yaml: ignoring, error in schema: properties: atomic-threshold-us
Documentation/devicetree/bindings/firmware/arm,scmi.example.dt.yaml:0:0: /example-0/firmware/scmi: failed to match any schema with compatible: ['arm,scmi']
Documentation/devicetree/bindings/firmware/arm,scmi.example.dt.yaml:0:0: /example-1/firmware/scmi: failed to match any schema with compatible: ['arm,scmi-smc']
Documentation/devicetree/bindings/mailbox/arm,mhu.example.dt.yaml:0:0: /example-1/firmware/scmi: failed to match any schema with compatible: ['arm,scmi']

doc reference errors (make refcheckdocs):

See https://patchwork.ozlabs.org/patch/1592136

This check can fail if there are any dependencies. The base for a patch
series is generally the most recent rc1.

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.

Re: [PATCH v4 4/8] dt-bindings: firmware: arm,scmi: Add atomic-threshold-us optional property

[Rob Herring]

On Sun, Feb 13, 2022 at 07:58:28PM +0000, Cristian Marussi wrote:
> SCMI protocols in the platform can optionally signal to the OSPM agent
> the expected execution latency for a specific resource/operation pair.
> 
> Introduce an SCMI system wide optional property to describe a global time
> threshold which can be configured on a per-platform base to determine the
> opportunity, or not, for an SCMI command advertised to have a higher
> latency than the threshold, to be considered for atomic operations:
> high-latency SCMI synchronous commands should be preferably issued in the
> usual non-atomic mode.
> 
> Cc: Rob Herring <robh+dt@kernel.org>
> Cc: devicetree@vger.kernel.org
> Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
> ---
> v3 --> v4
> - renamed property to atomic-threshold-us
> v1 --> v2
> - rephrased the property description
> ---
>  .../devicetree/bindings/firmware/arm,scmi.yaml        | 11 +++++++++++
>  1 file changed, 11 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/firmware/arm,scmi.yaml b/Documentation/devicetree/bindings/firmware/arm,scmi.yaml
> index eae15df36eef..3ffa669b91af 100644
> --- a/Documentation/devicetree/bindings/firmware/arm,scmi.yaml
> +++ b/Documentation/devicetree/bindings/firmware/arm,scmi.yaml
> @@ -81,6 +81,15 @@ properties:
>    '#size-cells':
>      const: 0
>  
> +  atomic-threshold-us:
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +    description:
> +      An optional time value, expressed in microseconds, representing, on this
> +      platform, the threshold above which any SCMI command, advertised to have
> +      an higher-than-threshold execution latency, should not be considered for
> +      atomic mode of operation, even if requested.

> +      If left unconfigured defaults to zero.

This can be expressed as 'default: 0'.

> +
>    arm,smc-id:
>      $ref: /schemas/types.yaml#/definitions/uint32
>      description:
> @@ -264,6 +273,8 @@ examples:
>              #address-cells = <1>;
>              #size-cells = <0>;
>  
> +            atomic_threshold = <10000>;
> +
>              scmi_devpd: protocol@11 {
>                  reg = <0x11>;
>                  #power-domain-cells = <1>;
> -- 
> 2.17.1
> 
> 

Re: [PATCH v4 4/8] dt-bindings: firmware: arm,scmi: Add atomic-threshold-us optional property

[Cristian Marussi]

On Tue, Feb 15, 2022 at 03:03:52PM -0600, Rob Herring wrote:
> On Sun, Feb 13, 2022 at 07:58:28PM +0000, Cristian Marussi wrote:
> > SCMI protocols in the platform can optionally signal to the OSPM agent
> > the expected execution latency for a specific resource/operation pair.
> > 
> > Introduce an SCMI system wide optional property to describe a global time
> > threshold which can be configured on a per-platform base to determine the
> > opportunity, or not, for an SCMI command advertised to have a higher
> > latency than the threshold, to be considered for atomic operations:
> > high-latency SCMI synchronous commands should be preferably issued in the
> > usual non-atomic mode.
> > 
> > Cc: Rob Herring <robh+dt@kernel.org>
> > Cc: devicetree@vger.kernel.org
> > Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
> > ---
> > v3 --> v4
> > - renamed property to atomic-threshold-us
> > v1 --> v2
> > - rephrased the property description
> > ---
> >  .../devicetree/bindings/firmware/arm,scmi.yaml        | 11 +++++++++++
> >  1 file changed, 11 insertions(+)
> > 
> > diff --git a/Documentation/devicetree/bindings/firmware/arm,scmi.yaml b/Documentation/devicetree/bindings/firmware/arm,scmi.yaml
> > index eae15df36eef..3ffa669b91af 100644
> > --- a/Documentation/devicetree/bindings/firmware/arm,scmi.yaml
> > +++ b/Documentation/devicetree/bindings/firmware/arm,scmi.yaml
> > @@ -81,6 +81,15 @@ properties:
> >    '#size-cells':
> >      const: 0
> >  
> > +  atomic-threshold-us:
> > +    $ref: /schemas/types.yaml#/definitions/uint32
> > +    description:
> > +      An optional time value, expressed in microseconds, representing, on this
> > +      platform, the threshold above which any SCMI command, advertised to have
> > +      an higher-than-threshold execution latency, should not be considered for
> > +      atomic mode of operation, even if requested.
> 
> > +      If left unconfigured defaults to zero.
> 
> This can be expressed as 'default: 0'.
> 

Thanks, I'll fix next V5 together with the warnings/errors fixes exposed
by your DT check bot (I had an obsoleted dtschema package indeed...)

Possibly tomorrow I'll send a v5.

Thanks,
Cristian