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

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Date:   Tue, 29 Aug 2017 07:02:01 -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 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.

adam

>
> Thanks,
> Sekhar