Received-SPF: pass (google.com: domain of linux-wireless-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Wed, 21 Jun 2023 17:36:17 +0200
From:   Andrew Lunn <andrew@lunn.ch>
To:     Evan Quan <evan.quan@amd.com>
Cc:     rafael@kernel.org, lenb@kernel.org, alexander.deucher@amd.com,
        christian.koenig@amd.com, Xinhui.Pan@amd.com, airlied@gmail.com,
        daniel@ffwll.ch, johannes@sipsolutions.net, davem@davemloft.net,
        edumazet@google.com, kuba@kernel.org, pabeni@redhat.com,
        mario.limonciello@amd.com, mdaenzer@redhat.com,
        maarten.lankhorst@linux.intel.com, tzimmermann@suse.de,
        hdegoede@redhat.com, jingyuwang_vip@163.com, lijo.lazar@amd.com,
        jim.cromie@gmail.com, bellosilicio@gmail.com,
        andrealmeid@igalia.com, trix@redhat.com, jsg@jsg.id.au,
        arnd@arndb.de, linux-kernel@vger.kernel.org,
        linux-acpi@vger.kernel.org, amd-gfx@lists.freedesktop.org,
        dri-devel@lists.freedesktop.org, linux-wireless@vger.kernel.org,
        netdev@vger.kernel.org
Subject: Re: [PATCH V4 1/8] drivers/acpi: Add support for Wifi band RF
 mitigations
Message-ID: <3a7c8ffa-de43-4795-ae76-5cd9b00c52b5@lunn.ch>
References: <20230621054603.1262299-1-evan.quan@amd.com>
 <20230621054603.1262299-2-evan.quan@amd.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20230621054603.1262299-2-evan.quan@amd.com>
Precedence: bulk

On Wed, Jun 21, 2023 at 01:45:56PM +0800, Evan Quan wrote:
> From: Mario Limonciello <mario.limonciello@amd.com>
> 
> Due to electrical and mechanical constraints in certain platform designs
> there may be likely interference of relatively high-powered harmonics of
> the (G-)DDR memory clocks with local radio module frequency bands used
> by Wifi 6/6e/7.
> 
> To mitigate this, AMD has introduced an ACPI based mechanism that
> devices can use to notify active use of particular frequencies so
> that devices can make relative internal adjustments as necessary
> to avoid this resonance.

Do only ACPI based systems have:

   interference of relatively high-powered harmonics of the (G-)DDR
   memory clocks with local radio module frequency bands used by
   Wifi 6/6e/7."

Could Device Tree based systems not experience this problem?

> +/**
> + * 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.

       Andrew