netdev - Re: 32-bit Amlogic SoCs: avoid using Ethernet MAC addresses

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Date:   Tue, 26 Feb 2019 17:43:36 +0530
From:   Anand Moon <linux.amoon@...il.com>
To:     Martin Blumenstingl <martin.blumenstingl@...glemail.com>
Cc:     Bartosz Golaszewski <bgolaszewski@...libre.com>,
        linux-amlogic@...ts.infradead.org, netdev@...r.kernel.org
Subject: Re: 32-bit Amlogic SoCs: avoid using Ethernet MAC addresses

Hi Martin,

On Tue, 26 Feb 2019 at 17:07, Martin Blumenstingl
<martin.blumenstingl@...glemail.com> wrote:
>
> Hi Anand,
>
> On Tue, Feb 26, 2019 at 11:26 AM Anand Moon <linux.amoon@...il.com> wrote:
> >
> > Hi Martin,
> >
> > On Mon, 25 Feb 2019 at 17:49, Anand Moon <linux.amoon@...il.com> wrote:
> > >
> > > hi Martin,
> > >
> > > +Bartosz Golaszewski <bgolaszewski@...libre.com>
> > >
> > > On Mon, 25 Feb 2019 at 02:25, Martin Blumenstingl
> > > <martin.blumenstingl@...glemail.com> wrote:
> > > >
> > > > I have seen Anand's your question in [0]:
> > > > > only issue is I have is the each time their is random MAC address so I
> > > > > get new IP from dhcp server.
> > > > > How can I avoid this. I have tried to enable eFuse driver but with no success.
> > > >
> > > > u-boot on the 64-bit SoCs can read the MAC address from the eFuse and
> > > > pass it (via the .dtb) to the kernel.
> > > > This requires an ethernet0 alias in the mainline .dts though, see [1]
> > > > for and example.
> > > >
> > > > I'm not sure if this also works with the older u-boot on the 32-bit SoCs.
> > > > if it doesn't then there's a nvmem-cells binding for all Ethernet
> > > > controllers: [2] (please note that the function implementing this
> > > > binding was recently renamed: [3])
> > > > as far as I can tell the stmmac driver doesn't support the nvmem-cells
> > > > based binding yet
> > > >
> > > > Anand, if you want to work on this: feel free to do so!
> > > > I have the SDHC MMC driver and a discussion about the power-domain
> > > > drivers on my TODO-list, so I'm pretty busy at the moment.
> > > >
> > > >
> > > > Regards
> > > > Martin
> > > >
> > >
> > > Thanks for your inputs :) 8)
> > >
> > > After enable CONFIG_MESON_MX_EFUSE and added the alias
> > >
> >
> > As far as I can tell this nvmem consist of field.
> >  Board ID
> >  MAC address
> >  Serial Number
> >  UID
> >
> > I feel efues value in nvmem are read with following offset just for testing.
> > but it also need some driver changes to read from secure memory
> > by enable CONFIG_MESON_SM and get the mac address to be set in ethernet driver.
> > > On Odroid C1+
> > > # hexdump /sys/devices/platform/soc/da000000.secbus/da000000.nvmem/meson8b-efuse0/nvmem
> > > 0000000 1143 0000 4b48 3143 3131 3232 3346 4537
> > > 0000010 3942 4432 0000 0000 0000 0000 0000 0000
> > > 0000020 0000 0000 0000 0000 0000 0000 0000 0000
> > > *
> > > 00001b0 0000 0000 1e00 1006 addc 0000 0000 0000    *00:1e:06:10:dc:ad*
> > > mac address from nvmem
> > > 00001c0 0000 0000 0000 4b48 3143 3133 3631 3131
> > > 00001d0 3732 3130 6237 6537 3165 6437 3034 3764
> > > 00001e0 02ad ec24 ff7f acfb d692 5300 0047 0000
> > > 00001f0 0000 0000 0000 aff6 a000 0000 1400 c100
> > > 0000200
> > >
> > arch/arm/boot/dts/meson8b.dtsi
> > @@ -360,6 +360,18 @@
> >         compatible = "amlogic,meson8b-efuse";
> >         clocks = <&clkc CLKID_EFUSE>;
> >         clock-names = "core";
> > +
> > +       board_sn: board-sn@...0000 {
> > +               reg = <0x0000000 0x10>;
> > +       };
> > +
> > +       eth_mac: eth-mac@...01b4 {
> > +               reg = <0x00001b4 0x6>;
> > +       };
> > +
> > +       board_sno: board-sno@...01c0 {
> > +               reg = <0x00001c0 0x30>;
> > +       };
> >
> > This is what I am looking into.
> > If you have some input please share.
> your findings are looking good to me!
>
> I believe that some of the offsets are specific to the Odroid-C1.
> this is what the Endless Mini EC-100's kernel uses: [0] (eth_mac
> matches, but it seems that the other two don't)
>
>
.title = "mac", //for the main network interface
.id = EFUSE_MAC_ID,
.offset = 436,
.enc_len = 6,
.data_len = 6,

offset for mac which is in dec *436* is equal to hex *0x1b4* which I
am using for testing now.

I am changing this offset setting so that I get consistence result out of it.
I will also check with armbina image and see if I can find some thing usefull.

Thanks for your valuable inputs once again :)

Best Regards
-Anand

>
> [0] https://github.com/endlessm/linux-meson/blob/9969d20dc0f034e7a5addd4f6d28a8193e956b16/drivers/amlogic/efuse/efuse_version.c#L519