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Date:   Wed, 6 Apr 2022 10:32:14 +0200
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Subject: Re: [PATCH v2 04/14] dt-bindings: arm: mediatek: document WED binding
 for MT7622
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To:     Arnd Bergmann <arnd@arndb.de>
Cc:     Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>,
        Networking <netdev@vger.kernel.org>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzk+dt@kernel.org>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        Lorenzo Bianconi <lorenzo@kernel.org>,
        DTML <devicetree@vger.kernel.org>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>,
        "moderated list:ARM/Mediatek SoC..." 
        <linux-mediatek@lists.infradead.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
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 <CAK8P3a1A6QYajv_HTw79HjiJ8CN6YPeKXc_X3ZFD83pdOqVTkQ@mail.gmail.com>
From:   Felix Fietkau <nbd@nbd.name>
In-Reply-To: <CAK8P3a1A6QYajv_HTw79HjiJ8CN6YPeKXc_X3ZFD83pdOqVTkQ@mail.gmail.com>
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On 06.04.22 10:29, Arnd Bergmann wrote:
> On Wed, Apr 6, 2022 at 10:18 AM Felix Fietkau <nbd@nbd.name> wrote:
>> On 06.04.22 10:09, Krzysztof Kozlowski wrote:
>> > On 05/04/2022 21:57, Felix Fietkau wrote:
>> >> From: Lorenzo Bianconi <lorenzo@kernel.org>
>> >>
>> >> Document the binding for the Wireless Ethernet Dispatch core on the MT7622
>> >> SoC, which is used for Ethernet->WLAN offloading
>> >> Add related info in mediatek-net bindings.
>> >>
>> >> Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
>> >> Signed-off-by: Felix Fietkau <nbd@nbd.name>
>> >
>> > Thank you for your patch. There is something to discuss/improve.
>> >
>> >> ---
>> >>  .../arm/mediatek/mediatek,mt7622-wed.yaml     | 50 +++++++++++++++++++
>> >>  .../devicetree/bindings/net/mediatek-net.txt  |  2 +
>> >>  2 files changed, 52 insertions(+)
>> >>  create mode 100644 Documentation/devicetree/bindings/arm/mediatek/mediatek,mt7622-wed.yaml
>> >
>> > Don't store drivers in arm directory. See:
>> > https://lore.kernel.org/linux-devicetree/YkJa1oLSEP8R4U6y@robh.at.kernel.org/
>> >
>> > Isn't this a network offload engine? If yes, then probably it should be
>> > in "net/".
>> It's not a network offload engine by itself. It's a SoC component that
>> connects to the offload engine and controls a MTK PCIe WLAN device,
>> intercepting interrupts and DMA rings in order to be able to inject
>> packets coming in from the offload engine.
>> Do you think it still belongs in net, or maybe in soc instead?
> 
> I think it belongs into drivers/net/. Presumably this has some kind of
> user interface to configure which packets are forwarded? I would not
> want to maintain that in a SoC driver as this clearly needs to communicate
> with both of the normal network devices in some form.
The WLAN driver attaches to WED in order to deal with the intercepted 
DMA rings, but other than that, WED itself has no user configuration.
Offload is controlled by the PPE code in the ethernet driver (which is 
already upstream), and WED simply provides a destination port for PPE, 
which allows packets to flow to the wireless device.

- Felix