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

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Message-ID: <CANAwSgSw4dCQnHv0cMSxDs7S=83NUh5B6M8m_-ooFQKv02=v_g@mail.gmail.com>
Date:   Tue, 26 Feb 2019 15:55:56 +0530
From:   Anand Moon <linux.amoon@...il.com>
To:     Martin Blumenstingl <martin.blumenstingl@...glemail.com>,
        Bartosz Golaszewski <bgolaszewski@...libre.com>
Cc:     linux-amlogic@...ts.infradead.org, netdev@...r.kernel.org
Subject: Re: 32-bit Amlogic SoCs: avoid using Ethernet MAC addresses

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.

>
> Odroid C2:
> I could clearly observe the same.
>
> [root@...hl-c2l alarm]# hexdump /sys/devices/platform/efuse/efuse0/nvmem
> 0000000 0000 0000 0000 0000 0000 0000 0000 0000
> 0000010 0000 0000 4b48 3243 3331 3532 4434 4346
> 0000020 4145 4146 0000 0000 0000 0000 0000 0000
> 0000030 0000 0000 1e00 3306 7a37 0000 0000 0000     *00:1e:06:33:37:7a*
> 0000040 0000 0000 0000 4b48 3243 3132 3631 3430
> 0000050 3834 3932 3631 3837 3937 3466 6233 6366
> 0000060 357c c7ec cc98 0f6d 65b7 92cf 000b 0a00
> 0000070 0000 0000 0000 0000 0000 0000 0000 0000
> 0000080 0014 0000 0000 0000 0000 0000 0000 0000
> 0000090 0000 0000 0000 0000 0000 0000 0000 0000
> *
       efuse: efuse {
                compatible = "amlogic,meson-gx-efuse",
"amlogic,meson-gxbb-efuse";
                #address-cells = <1>;
                #size-cells = <1>;
                read-only;

                sn: sn@14 {
                        reg = <0x14 0x10>;
                };

                eth_mac: eth_mac@34 {
                        reg = <0x34 0x10>;
                };

                bid: bid@46 {
                        reg = <0x46 0x30>;
                };
        };

> >
> > [0] http://lists.infradead.org/pipermail/linux-amlogic/2019-February/010464.html
> > [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=f7c36209c46c4d162202b65eed2e66962ad8c3c1
> > [2] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=9217e566bdee4583d0a9ea4879c8f5e004886eac
> > [3] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=afa64a72b862a7a9d04f8d07fba632eaf06b23f8
>
> Yes thanks for the inputs.
>
> I see c85efcc60a892210aa10688d5de1f997d5cad799 ("ARM: davinci:
> da830-evm: use cell nvmem lookup for mac address")
> I do not know what this changes will help get the mac address from nvmem region.
>
> If some body could share some inputs it will be better for me to debug.
>
> Best Regards
> -Anand

Best Regards
-Anand