On 6/21/2023 11:31 AM, Andrew Lunn wrote:
I think there is enough details for this to happen. It's done
so that either the AML can natively behave as a consumer or a
driver can behave as a consumer.
+/**
+ * APIs needed by drivers/subsystems for contributing frequencies:
+ * During probe, check `wbrf_supported_producer` to see if WBRF is supported.
+ * If adding frequencies, then call `wbrf_add_exclusion` with the
+ * start and end points specified for the frequency ranges added.
+ * If removing frequencies, then call `wbrf_remove_exclusion` with
+ * start and end points specified for the frequency ranges added.
+ */
+bool wbrf_supported_producer(struct acpi_device *adev);
+int wbrf_add_exclusion(struct acpi_device *adev,
+ struct wbrf_ranges_in *in);
+int wbrf_remove_exclusion(struct acpi_device *adev,
+ struct wbrf_ranges_in *in);
Could struct device be used here, to make the API agnostic to where
the information is coming from? That would then allow somebody in the
future to implement a device tree based information provider.
That does make sense, and it wouldn't even be that much harder if we
assume in a given platform there's only one provider
That seems like a very reasonable assumption. It is theoretically
possible to build an ACPI + DT hybrid, but i've never seen it actually
done.
If an ARM64 ACPI BIOS could implement this, then i would guess the low
level bits would be solved, i guess jumping into the EL1
firmware. Putting DT on top instead should not be too hard.
Andrew
To make life easier I'll ask whether we can include snippets of
the matching ASL for this first implementation as part of the
public ACPI spec that matches this code when we release it.
So it sounds like you are pretty open about this, there should be
enough information for independent implementations. So please do make
the APIs between the providers and the consumers abstract, struct
device, not an ACPI object.
Andrew
Think a little more about what a non-ACPI implementation
would look like:
1) Would producers and consumers still need you to set CONFIG_ACPI_WBRF?
2) How would you indicate you need WBRF support?
3) How would notifications from one device to another work?
I don't think those are trivial problems that can be solved by
just making the pointer 'struct device' particularly as with the
ACPI implementation consumers are expecting the notification from
ACPI.
