Re: Fwd: DA850-evm MAC Address is random

From: Tony Lindgren <tony@atomide.com>
To: Adam Ford <aford173@gmail.com>
Cc: Grygorii Strashko <grygorii.strashko@ti.com>,
	linux-omap@vger.kernel.org, netdev@vger.kernel.org,
	Sekhar Nori <nsekhar@ti.com>
Subject: Re: Fwd: DA850-evm MAC Address is random
Date: Mon, 28 Aug 2017 14:12:17 -0700	[thread overview]
Message-ID: <20170828211217.GO6008@atomide.com> (raw)
In-Reply-To: <CAHCN7xLHEjda9DcVw5iHA9RaJ7UnyMVxf7e4e8NTEj9Op1JaBw@mail.gmail.com>

* Adam Ford <aford173@gmail.com> [170828 13:33]:
> On Mon, Aug 28, 2017 at 1:54 PM, Grygorii Strashko
> <grygorii.strashko@ti.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
> 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
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.

Regards,

Tony