netdev - Re: Fwd: DA850-evm MAC Address is random

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Date:   Tue, 29 Aug 2017 10:20:50 -0500
From:   Adam Ford <aford173@...il.com>
To:     Sekhar Nori <nsekhar@...com>
Cc:     Tony Lindgren <tony@...mide.com>,
        Grygorii Strashko <grygorii.strashko@...com>,
        linux-omap@...r.kernel.org, netdev@...r.kernel.org
Subject: Re: Fwd: DA850-evm MAC Address is random

On Tue, Aug 29, 2017 at 10:16 AM, Sekhar Nori <nsekhar@...com> wrote:
> On Tuesday 29 August 2017 05:32 PM, Adam Ford wrote:
>> On Tue, Aug 29, 2017 at 6:42 AM, Sekhar Nori <nsekhar@...com> wrote:
>>> On Tuesday 29 August 2017 03:53 PM, Adam Ford wrote:
>>>> On Tue, Aug 29, 2017 at 3:23 AM, Sekhar Nori <nsekhar@...com> wrote:
>>>>> On Tuesday 29 August 2017 02:42 AM, Tony Lindgren wrote:
>>>>>> * Adam Ford <aford173@...il.com> [170828 13:33]:
>>>>>>> On Mon, Aug 28, 2017 at 1:54 PM, Grygorii Strashko
>>>>>>> <grygorii.strashko@...com> wrote:
>>>>>>>> Cc: Sekhar
>>>>>>>>
>>>>>>>> On 08/28/2017 10:32 AM, Adam Ford wrote:
>>>>>>>>>
>>>>>>>>> The davinvi_emac MAC address seems to attempt a call to
>>>>>>>>> ti_cm_get_macid in cpsw-common.c but it returns the message
>>>>>>>>> 'davinci_emac davinci_emac.1: incompatible machine/device type for
>>>>>>>>> reading mac address ' and then generates a random MAC address.
>>>>>>>>>
>>>>>>>>> The function appears to lookup varions boards using
>>>>>>>>> 'of_machine_is_compaible' and supports dm8148, am33xx, am3517, dm816,
>>>>>>>>> am4372 and dra7.  I don't see the ti,davinci-dm6467-emac which is
>>>>>>>>> what's shown in the da850 device tree.
>>>>>>>>>
>>>>>>>>> Is there a patch somewhere for supporting the da850-evm?
>>>>>>>>
>>>>>>>>
>>>>>>>> Not sure if MAC address can be read from Control module.
>>>>>>>> May be Sekhar can say more?
>>>>>>>
>>>>>>> My understanding is that the MAC address is programmed by Logic PD
>>>>>>> into the SPI flash.  The Bootloader reads this from either SPI or its
>>>>>>> env variables.  Looking at the partition info listed in the
>>>>>>> da850-evm.dts file, it appears as if they've reserved space for it.
>>>>>>> Unfortunately, I don't see any code that reads it out.  I was hoping
>>>>>
>>>>> This code is present in U-Boot sources at
>>>>> board/davinci/da8xxevm/da850evm.c. See the function get_mac_addr() and
>>>>> its usage in misc_init_r().
>>>>>
>>>>>>> there might be a way to just pass cmdline parameter from the
>>>>>>> bootloader to the kernel to accept the MAC address.
>>>>>>>
>>>>>>>>
>>>>>>>>>
>>>>>>>>> If not, is there a way to pass the MAC address from U-Boot to the
>>>>>>>>> driver so it doesn't generate a random MAC?
>>>>>>>>
>>>>>>>>
>>>>>>>> "local-mac-address" dt porp
>>>>>>>
>>>>>>> The downside here, is that we'd have to have the Bootloader modify the
>>>>>>> device tree.
>>>>>>
>>>>>> That piece of code exists somewhere in u-boot already. Note how
>>>>>
>>>>> Yes, it is fdt_fixup_ethernet() and its usage is in common/image-fdt.c.
>>>>>
>>>>>> we are populating the mac address for USB Ethernet drivers in
>>>>>> u-boot and then the Ethernet driver code parses it. See commit
>>>>>> 055d31de7158 ("ARM: omap3: beagleboard-xm: dt: Add ethernet to
>>>>>> the device tree") for some more information.
>>>>>>
>>>>>> I think u-boot needs the ethernet alias for finding the interface.
>>>>>
>>>>> That's exactly what was missing. I have sent a patch for fixing that and
>>>>> copied you there.
>>>>
>>>> Thanks for doing that.
>>>>
>>>>>
>>>>> Adam, if I can get your Tested-by, I will make an attempt to send it for
>>>>> v4.13 itself.
>>>>
>>>> I will test it.  Do need to run some instruction or do something
>>>> special in U-Boot to pass this in the proper place for the kernel to
>>>> pull it?  Tony's patch reference showed
>>>> command for fdt set, but I am not sure I fully understand the
>>>> parameters that went along with that.
>>>
>>> Nope, just applying the patch and booting the with the new dtb should
>>> result in the random mac address going away.
>>
>> Unfortunately, I am not seeing any change with the patch (at least
>> with Kernel 4.12.9 from stable).
>>
>> netconsole: network logging started
>> davinci_emac davinci_emac.1: incompatible machine/device type for
>> reading mac address
>> davinci_emac davinci_emac.1: using random MAC addr: ee:74:c3:3a:15:be
>>
>> Looking at the source for cpsw-common.c function ti_cm_get_macid()
>> doesn't have a case for the  ti,davinci-dm6467-emac so I wonder if
>> there might be more to it.
>
> Hmm, it did solve the issue for me when I tried latest -next. And
> reverting the patch brought back the random mac address usage. Could you
> try latest mainline or -next?
>
> Meanwhile let me see whats going on with the observations you have.

I will try again with -next this afternoon and see what I can find.
Can you tell me which U-Boot version you're using? I want to match
your setup. I want to see if something is missing during the hand-off
between the Bootloader and Linux.


>
> Thanks,
> Sekhar