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From:   Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Date:   Mon, 29 Jul 2019 23:45:51 +0200
Message-ID: <CAFBinCC5Bz-Oe4G1dtABrU+RFWUmqpdgyuDdRPp=Mo_Cucz7Wg@mail.gmail.com>
Subject: Re: [PATCH 1/2] ARM: dts: meson8b: add the nvmem cell with the
 board's MAC address
To:     Neil Armstrong <narmstrong@baylibre.com>,
        hexdump0815@googlemail.com
Cc:     linux-amlogic@lists.infradead.org, khilman@baylibre.com,
        linux.amoon@gmail.com, linux-kernel@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org, ottuzzi@gmail.com
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On Mon, Jul 29, 2019 at 9:11 AM Neil Armstrong <narmstrong@baylibre.com> wrote:
>
> Hi Martin,
>
> On 27/07/2019 21:46, Martin Blumenstingl wrote:
> > Amlogic's BSP kernel defines that all boards with a MAC address stored
> > in the eFuse have it at offset 0x1b4. It is up to the board to
> > decide whether to use this MAC address or not:
> > - Odroid-C1 uses the MAC address from the eFuse
> > - EC-100 seems to read the MAC address from eMMC
> >
> > Add the nvmem cell which describes the Ethernet MAC address. Don't
> > assign it to the Ethernet controller, because depending on the board the
> > actual MAC address may be read from somewhere else.
> >
> > Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
> > ---
> >  arch/arm/boot/dts/meson8b.dtsi | 4 ++++
> >  1 file changed, 4 insertions(+)
> >
> > diff --git a/arch/arm/boot/dts/meson8b.dtsi b/arch/arm/boot/dts/meson8b.dtsi
> > index 30fca9bb4bbe..c7de58b71d08 100644
> > --- a/arch/arm/boot/dts/meson8b.dtsi
> > +++ b/arch/arm/boot/dts/meson8b.dtsi
> > @@ -402,6 +402,10 @@
> >       clocks = <&clkc CLKID_EFUSE>;
> >       clock-names = "core";
> >
> > +     ethernet_mac_address: mac@1b4 {
> > +             reg = <0x1b4 0x6>;
> > +     };
>
> Is this a fixed position for all boards ? if not, I'll suggest moving
> it to the odroid-c1 dt until you have more users.
the 0x1b4 offset is hardcoded in Amlogic's kernel sources
if some board uses another offset then the manufacturer had to patch
the kernel to make it work (like Endless did)

+Cc hexdump0815 - can you please run the following command on your
Meson8b MXQ board:
$ hexdump -C /sys/bus/nvmem/devices/meson8b-efuse0/nvmem | grep
000001b0 | cut -d' ' -f7,8,9,10,12,13

this should print the MAC address that is also used by the stock
firmware and/or printed on the board
if it is then I'm happy to provide a patch also for your MXQ board so
it also uses the correct MAC address


Martin