linux-kernel - Re: [PATCH V4 1/8] drivers/acpi: Add support for Wifi band RF mitigations

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Message-ID: <9435a928-04c4-442f-89f2-e76713c908a5@lunn.ch>
Date:   Wed, 21 Jun 2023 18:31:04 +0200
From:   Andrew Lunn <andrew@...n.ch>
To:     "Limonciello, Mario" <mario.limonciello@....com>
Cc:     Johannes Berg <johannes@...solutions.net>,
        Evan Quan <evan.quan@....com>, rafael@...nel.org,
        lenb@...nel.org, alexander.deucher@....com,
        christian.koenig@....com, Xinhui.Pan@....com, airlied@...il.com,
        daniel@...ll.ch, davem@...emloft.net, edumazet@...gle.com,
        kuba@...nel.org, pabeni@...hat.com, mdaenzer@...hat.com,
        maarten.lankhorst@...ux.intel.com, tzimmermann@...e.de,
        hdegoede@...hat.com, jingyuwang_vip@....com, lijo.lazar@....com,
        jim.cromie@...il.com, bellosilicio@...il.com,
        andrealmeid@...lia.com, trix@...hat.com, jsg@....id.au,
        arnd@...db.de, linux-kernel@...r.kernel.org,
        linux-acpi@...r.kernel.org, amd-gfx@...ts.freedesktop.org,
        dri-devel@...ts.freedesktop.org, linux-wireless@...r.kernel.org,
        netdev@...r.kernel.org
Subject: Re: [PATCH V4 1/8] drivers/acpi: Add support for Wifi band RF
 mitigations

> 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