From:   Kalle Valo <kvalo@kernel.org>
To:     Heiko Thiery <heiko.thiery@gmail.com>
Cc:     Michael Walle <michael@walle.cc>, Jakub Kicinski <kuba@kernel.org>,
        Ajay.Kathat@microchip.com, Claudiu.Beznea@microchip.com,
        linux-wireless@vger.kernel.org, netdev@vger.kernel.org,
        Amisha.Patel@microchip.com, Thomas Haller <thaller@redhat.com>,
        Beniamino Galvani <bgalvani@redhat.com>
Subject: Re: wilc1000 MAC address is 00:00:00:00:00:00
In-Reply-To: <CAEyMn7bpwusVarzHa262maJHf6XTpCW4SL0-o+YH4DGZx94+hw@mail.gmail.com>
        (Heiko Thiery's message of "Fri, 10 Feb 2023 10:17:24 +0100")
References: <CAEyMn7aV-B4OEhHR4Ad0LM3sKCz1-nDqSb9uZNmRWR-hMZ=z+A@mail.gmail.com>
        <e027bfcf-1977-f2fa-a362-8faed91a19f9@microchip.com>
        <20230209094825.49f59208@kernel.org>
        <51134d12-1b06-6d6f-e798-7dd681a8f3ae@microchip.com>
        <20230209130725.0b04a424@kernel.org>
        <2d548e01b266f7b1ad19a5ea979d00bf@walle.cc>
        <CAEyMn7bpwusVarzHa262maJHf6XTpCW4SL0-o+YH4DGZx94+hw@mail.gmail.com>
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Date:   Fri, 10 Feb 2023 11:25:00 +0200
Message-ID: <87bkm1x47n.fsf@kernel.org>
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Heiko Thiery <heiko.thiery@gmail.com> writes:

> HI,
>
> Am Do., 9. Feb. 2023 um 22:19 Uhr schrieb Michael Walle <michael@walle.cc>:
>>
>> Am 2023-02-09 22:07, schrieb Jakub Kicinski:
>> > On Thu, 9 Feb 2023 18:51:58 +0000 Ajay.Kathat@microchip.com wrote:
>> >> > netdev should be created with a valid lladdr, is there something
>> >> > wifi-specific here that'd prevalent that? The canonical flow is
>> >> > to this before registering the netdev:
>> >>
>> >> Here it's the timing in wilc1000 by when the MAC address is available
>> >> to
>> >> read from NV. NV read is available in "mac_open" net_device_ops
>> >> instead
>> >> of bus probe function. I think, mostly the operations on netdev which
>> >> make use of mac address are performed after the "mac_open" (I may be
>> >> missing something).
>> >>
>> >> Does it make sense to assign a random address in probe and later read
>> >> back from NV in mac_open to make use of stored value?
>> >
>> > Hard to say, I'd suspect that may be even more confusing than
>> > starting with zeroes. There aren't any hard rules around the
>> > addresses AFAIK, but addrs are visible to user space. So user
>> > space will likely make assumptions based on the most commonly
>> > observed sequence (reading real addr at probe).
>>
>> Maybe we should also ask the NetworkManager guys. IMHO random
>> MAC address sounds bogus.
>
> Maybe it would be a "workaround" with loading the firmware while
> probing the device to set the real hw address.
>
> probe()
>   load_fw()
>   read_hw_addr_from_nv()
>   eth_hw_addr_set(ndev, addr)
>   unload_fw()
>
> mac_open()
>   load_fw()
>
> mac_close()
>   unload_fw()

This is exactly what many wireless drivers already do and I recommend
that wilc1000 would do the same.

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