Adding bindings to represent a virtual cpufreq device.
Virtual machines may expose MMIO regions for a virtual cpufreq device for
guests to read frequency information or to request frequency selection. The
virtual cpufreq device has an individual controller for each CPU.
Co-developed-by: Saravana Kannan <[email protected]>
Signed-off-by: Saravana Kannan <[email protected]>
Signed-off-by: David Dai <[email protected]>
---
.../bindings/cpufreq/cpufreq-virtual.yaml | 89 +++++++++++++++++++
1 file changed, 89 insertions(+)
create mode 100644 Documentation/devicetree/bindings/cpufreq/cpufreq-virtual.yaml
diff --git a/Documentation/devicetree/bindings/cpufreq/cpufreq-virtual.yaml b/Documentation/devicetree/bindings/cpufreq/cpufreq-virtual.yaml
new file mode 100644
index 000000000000..f377cfc972ca
--- /dev/null
+++ b/Documentation/devicetree/bindings/cpufreq/cpufreq-virtual.yaml
@@ -0,0 +1,89 @@
+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/cpufreq/cpufreq-virtual.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yamll#
+
+title: Virtual CPUFreq
+
+maintainers:
+ - David Dai <[email protected]>
+ - Saravana Kannan <[email protected]>
+
+description:
+ Virtual CPUFreq is a virtualized driver in guest kernels that sends frequency
+ selection of its vCPUs as a hint to the host through MMIO regions. The host
+ uses the hint to schedule vCPU threads and select physical CPU frequency. It
+ enables accurate Per-Entity Load Tracking for tasks running in the guest by
+ querying host CPU frequency unless a virtualized FIE (ex. AMU) exists.
+
+properties:
+ compatible:
+ const: virtual,cpufreq
+ reg:
+ maxItems: 1
+
+required:
+ - compatible
+ - reg
+
+additionalProperties: false
+
+examples:
+ - |
+ cpus {
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ cpu@0 {
+ compatible = "arm,arm-v8";
+ device_type = "cpu";
+ reg = <0x0>;
+ operating-points-v2 = <&opp_table0>;
+ };
+
+ cpu@1 {
+ compatible = "arm,arm-v8";
+ device_type = "cpu";
+ reg = <0x0>;
+ operating-points-v2 = <&opp_table1>;
+ };
+ };
+
+ opp_table0: opp-table-0 {
+ compatible = "operating-points-v2";
+
+ opp1098000000 {
+ opp-hz = /bits/ 64 <1098000000>;
+ opp-level = <1>;
+ };
+
+ opp1197000000 {
+ opp-hz = /bits/ 64 <1197000000>;
+ opp-level = <2>;
+ };
+ };
+
+ opp_table1: opp-table-1 {
+ compatible = "operating-points-v2";
+
+ opp1106000000 {
+ opp-hz = /bits/ 64 <1106000000>;
+ opp-level = <1>;
+ };
+
+ opp1277000000 {
+ opp-hz = /bits/ 64 <1277000000>;
+ opp-level = <2>;
+ };
+ };
+
+ soc {
+ #address-cells = <1>;
+ #size-cells = <1>;
+
+ cpufreq {
+ reg = <0x1040000 0x10>;
+ compatible = "virtual,cpufreq";
+ };
+ };
--
2.41.0.585.gd2178a4bd4-goog
On Mon, 31 Jul 2023 10:46:08 -0700, David Dai wrote:
> Adding bindings to represent a virtual cpufreq device.
>
> Virtual machines may expose MMIO regions for a virtual cpufreq device for
> guests to read frequency information or to request frequency selection. The
> virtual cpufreq device has an individual controller for each CPU.
>
> Co-developed-by: Saravana Kannan <[email protected]>
> Signed-off-by: Saravana Kannan <[email protected]>
> Signed-off-by: David Dai <[email protected]>
> ---
> .../bindings/cpufreq/cpufreq-virtual.yaml | 89 +++++++++++++++++++
> 1 file changed, 89 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/cpufreq/cpufreq-virtual.yaml
>
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:
Traceback (most recent call last):
File "/usr/local/lib/python3.10/dist-packages/jsonschema/validators.py", line 909, in resolve_from_url
document = self.store[url]
File "/usr/local/lib/python3.10/dist-packages/jsonschema/_utils.py", line 28, in __getitem__
return self.store[self.normalize(uri)]
KeyError: 'http://devicetree.org/meta-schemas/core.yamll'
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "/usr/local/lib/python3.10/dist-packages/jsonschema/validators.py", line 912, in resolve_from_url
document = self.resolve_remote(url)
File "/usr/local/lib/python3.10/dist-packages/jsonschema/validators.py", line 1011, in resolve_remote
result = self.handlers[scheme](uri)
File "/usr/local/lib/python3.10/dist-packages/dtschema/schema.py", line 91, in http_handler
raise RefResolutionError('Error in referenced schema matching $id: ' + uri)
jsonschema.exceptions.RefResolutionError: Error in referenced schema matching $id: http://devicetree.org/meta-schemas/core.yamll
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "/usr/local/bin/dt-doc-validate", line 64, in <module>
ret |= check_doc(f)
File "/usr/local/bin/dt-doc-validate", line 32, in check_doc
for error in sorted(dtsch.iter_errors(), key=lambda e: e.linecol):
File "/usr/local/lib/python3.10/dist-packages/dtschema/schema.py", line 130, in iter_errors
meta_schema = self.resolver.resolve_from_url(self['$schema'])
File "/usr/local/lib/python3.10/dist-packages/jsonschema/validators.py", line 914, in resolve_from_url
raise exceptions.RefResolutionError(exc)
jsonschema.exceptions.RefResolutionError: Error in referenced schema matching $id: http://devicetree.org/meta-schemas/core.yamll
Documentation/devicetree/bindings/cpufreq/cpufreq-virtual.example.dts:69.19-72.13: Warning (unit_address_vs_reg): /example-0/soc/cpufreq: node has a reg or ranges property, but no unit name
Documentation/devicetree/bindings/cpufreq/cpufreq-virtual.example.dtb: /example-0/cpus/cpu@0: failed to match any schema with compatible: ['arm,arm-v8']
Documentation/devicetree/bindings/cpufreq/cpufreq-virtual.example.dtb: /example-0/cpus/cpu@1: failed to match any schema with compatible: ['arm,arm-v8']
doc reference errors (make refcheckdocs):
See https://patchwork.ozlabs.org/project/devicetree-bindings/patch/[email protected]
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 31/07/2023 19:46, David Dai wrote:
> Adding bindings to represent a virtual cpufreq device.
>
> Virtual machines may expose MMIO regions for a virtual cpufreq device for
> guests to read frequency information or to request frequency selection. The
> virtual cpufreq device has an individual controller for each CPU.
A nit, subject: drop second/last, redundant "bindings for". The
"dt-bindings" prefix is already stating that these are bindings.
>
> Co-developed-by: Saravana Kannan <[email protected]>
> Signed-off-by: Saravana Kannan <[email protected]>
> Signed-off-by: David Dai <[email protected]>
> ---
> .../bindings/cpufreq/cpufreq-virtual.yaml | 89 +++++++++++++++++++
> 1 file changed, 89 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/cpufreq/cpufreq-virtual.yaml
>
> diff --git a/Documentation/devicetree/bindings/cpufreq/cpufreq-virtual.yaml b/Documentation/devicetree/bindings/cpufreq/cpufreq-virtual.yaml
> new file mode 100644
> index 000000000000..f377cfc972ca
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/cpufreq/cpufreq-virtual.yaml
> @@ -0,0 +1,89 @@
> +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/cpufreq/cpufreq-virtual.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yamll#
> +
> +title: Virtual CPUFreq
> +
> +maintainers:
> + - David Dai <[email protected]>
> + - Saravana Kannan <[email protected]>
> +
> +description:
> + Virtual CPUFreq is a virtualized driver in guest kernels that sends frequency
> + selection of its vCPUs as a hint to the host through MMIO regions. The host
> + uses the hint to schedule vCPU threads and select physical CPU frequency. It
> + enables accurate Per-Entity Load Tracking for tasks running in the guest by
> + querying host CPU frequency unless a virtualized FIE (ex. AMU) exists.
Why do you need DT for this? You control hypervisor, thus control the
interface to the guest. I think Rob made it pretty clear that
discoverable usecases (which is yours) are not for DT.
Incomplete style-review follows:
> +
> +properties:
> + compatible:
> + const: virtual,cpufreq
Missing blank line.
> + reg:
> + maxItems: 1
> +
> +required:
> + - compatible
> + - reg
> +
> +additionalProperties: false
> +
> +examples:
> + - |
> + cpus {
> + #address-cells = <1>;
> + #size-cells = <0>;
> +
> + cpu@0 {
> + compatible = "arm,arm-v8";
> + device_type = "cpu";
> + reg = <0x0>;
> + operating-points-v2 = <&opp_table0>;
> + };
> +
> + cpu@1 {
> + compatible = "arm,arm-v8";
> + device_type = "cpu";
> + reg = <0x0>;
> + operating-points-v2 = <&opp_table1>;
> + };
> + };
> +
> + opp_table0: opp-table-0 {
> + compatible = "operating-points-v2";
> +
> + opp1098000000 {
> + opp-hz = /bits/ 64 <1098000000>;
> + opp-level = <1>;
> + };
> +
> + opp1197000000 {
> + opp-hz = /bits/ 64 <1197000000>;
> + opp-level = <2>;
> + };
> + };
> +
> + opp_table1: opp-table-1 {
> + compatible = "operating-points-v2";
> +
> + opp1106000000 {
> + opp-hz = /bits/ 64 <1106000000>;
> + opp-level = <1>;
> + };
> +
> + opp1277000000 {
> + opp-hz = /bits/ 64 <1277000000>;
> + opp-level = <2>;
> + };
> + };
> +
> + soc {
> + #address-cells = <1>;
> + #size-cells = <1>;
> +
> + cpufreq {
Missing unit address
> + reg = <0x1040000 0x10>;
> + compatible = "virtual,cpufreq";
compatible is always the first property.
Also, you did not test it...
Best regards,
Krzysztof
On Sat, Aug 5, 2023 at 12:38 PM Krzysztof Kozlowski
<[email protected]> wrote:
>
> On 31/07/2023 19:46, David Dai wrote:
> > Adding bindings to represent a virtual cpufreq device.
> >
> > Virtual machines may expose MMIO regions for a virtual cpufreq device for
> > guests to read frequency information or to request frequency selection. The
> > virtual cpufreq device has an individual controller for each CPU.
>
> A nit, subject: drop second/last, redundant "bindings for". The
> "dt-bindings" prefix is already stating that these are bindings.
>
> >
> > Co-developed-by: Saravana Kannan <[email protected]>
> > Signed-off-by: Saravana Kannan <[email protected]>
> > Signed-off-by: David Dai <[email protected]>
> > ---
> > .../bindings/cpufreq/cpufreq-virtual.yaml | 89 +++++++++++++++++++
> > 1 file changed, 89 insertions(+)
> > create mode 100644 Documentation/devicetree/bindings/cpufreq/cpufreq-virtual.yaml
> >
> > diff --git a/Documentation/devicetree/bindings/cpufreq/cpufreq-virtual.yaml b/Documentation/devicetree/bindings/cpufreq/cpufreq-virtual.yaml
> > new file mode 100644
> > index 000000000000..f377cfc972ca
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/cpufreq/cpufreq-virtual.yaml
> > @@ -0,0 +1,89 @@
> > +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/cpufreq/cpufreq-virtual.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yamll#
> > +
> > +title: Virtual CPUFreq
> > +
> > +maintainers:
> > + - David Dai <[email protected]>
> > + - Saravana Kannan <[email protected]>
> > +
> > +description:
> > + Virtual CPUFreq is a virtualized driver in guest kernels that sends frequency
> > + selection of its vCPUs as a hint to the host through MMIO regions. The host
> > + uses the hint to schedule vCPU threads and select physical CPU frequency. It
> > + enables accurate Per-Entity Load Tracking for tasks running in the guest by
> > + querying host CPU frequency unless a virtualized FIE (ex. AMU) exists.
>
> Why do you need DT for this? You control hypervisor, thus control the
> interface to the guest. I think Rob made it pretty clear that
> discoverable usecases (which is yours) are not for DT.
>
> Incomplete style-review follows:
>
> > +
> > +properties:
> > + compatible:
> > + const: virtual,cpufreq
>
> Missing blank line.
>
> > + reg:
> > + maxItems: 1
> > +
> > +required:
> > + - compatible
> > + - reg
> > +
> > +additionalProperties: false
> > +
> > +examples:
> > + - |
> > + cpus {
> > + #address-cells = <1>;
> > + #size-cells = <0>;
> > +
> > + cpu@0 {
> > + compatible = "arm,arm-v8";
> > + device_type = "cpu";
> > + reg = <0x0>;
> > + operating-points-v2 = <&opp_table0>;
> > + };
> > +
> > + cpu@1 {
> > + compatible = "arm,arm-v8";
> > + device_type = "cpu";
> > + reg = <0x0>;
> > + operating-points-v2 = <&opp_table1>;
> > + };
> > + };
> > +
> > + opp_table0: opp-table-0 {
> > + compatible = "operating-points-v2";
> > +
> > + opp1098000000 {
> > + opp-hz = /bits/ 64 <1098000000>;
> > + opp-level = <1>;
> > + };
> > +
> > + opp1197000000 {
> > + opp-hz = /bits/ 64 <1197000000>;
> > + opp-level = <2>;
> > + };
> > + };
> > +
> > + opp_table1: opp-table-1 {
> > + compatible = "operating-points-v2";
> > +
> > + opp1106000000 {
> > + opp-hz = /bits/ 64 <1106000000>;
> > + opp-level = <1>;
> > + };
> > +
> > + opp1277000000 {
> > + opp-hz = /bits/ 64 <1277000000>;
> > + opp-level = <2>;
> > + };
> > + };
> > +
> > + soc {
> > + #address-cells = <1>;
> > + #size-cells = <1>;
> > +
> > + cpufreq {
>
> Missing unit address
>
> > + reg = <0x1040000 0x10>;
> > + compatible = "virtual,cpufreq";
>
> compatible is always the first property.
>
> Also, you did not test it...
Why do you say this? This patch series was obviously tested very well
with all the data we collected.
-Saravana
On 09/08/2023 01:31, Saravana Kannan wrote:
>>
>>> + reg = <0x1040000 0x10>;
>>> + compatible = "virtual,cpufreq";
>>
>> compatible is always the first property.
>>
>> Also, you did not test it...
>
> Why do you say this? This patch series was obviously tested very well
> with all the data we collected.
Why do I say? Because of warning and huge fat Python exception? Test
it... you will see.
Best regards,
Krzysztof