Re: Overriding MAC address via device_properties?

[Tom Trebisky <tom%mmto.org@localhost>]

I was working with the ROCK64 image from "armbsd.org" last night.

I uses a pretty old (2017.09) version of U-boot.  One of my goals for 
today was to rebuild
U-boot from the 2022.10 sources.  That will allow the saveenv command to 
work to
(in my case) the SD card -- it writes a file uenv.txt or some such in 
the EFI fat partition.

I saw that there were some NetBSD specific patches for U-boot 2022.10 so 
I need
to look at those (why would there be NetBSD specific patches to U-boot?)

I am working on the Orange Pi R1+ (another RK3328 board).

On 1/24/23 08:29, David Brownlee wrote:
> On Tue, 3 Jan 2023 at 15:01, Manuel Bouyer <bouyer%antioche.eu.org@localhost> wrote:
> > On Sat, Dec 31, 2022 at 09:06:23AM +0900, Chris wrote:
> > > Hello,
> > >
> > > I have a few rock64s running NetBSD-9.  I'm trying to migrate them from microSD
> > > cards to eMMC, and apparently the rock64 u-boot isn't able to write its
> > > environment to eMMC.
> > >
> > > That's unfortunate, because the rock64 doesn't have a unique per-board MAC
> > > address.  If the MAC address isn't explicitly set in the u-boot environment,
> > > all boards will use 9e:6b:01:38:f7:da.
> > >
> > > Attempting to override the MAC address via ifconfig's 'link <address> active'
> > > kills the awge interface completely.
> > >
> > > I'm planning on untangling that issue, as well as the u-boot issue, but in the
> > > meantime I need to get these boards running with unique MAC addresses.
> > >
> > > I see this bit in sys/dev/ic/dwc_gmac.c:
> > >
> > >          prop_data_t ea = dict ? prop_dictionary_get(dict, "mac-address") : NULL;
> > >          if (ea != NULL) {
> > >                  /*
> > >                   * If the MAC address is overriden by a device property,
> > >                   * use that.
> > >                   */
> > >                  KASSERT(prop_object_type(ea) == PROP_TYPE_DATA);
> > >                  KASSERT(prop_data_size(ea) == ETHER_ADDR_LEN);
> > >                  memcpy(enaddr, prop_data_data_nocopy(ea), ETHER_ADDR_LEN);
> > >          }
> > >
> > > ... which leads me to believe that there's a way to specify the MAC address via
> > > a property dictionary.
> > >
> > > However, I haven't been able to find any documentation on where that is
> > > actually configured.  Adding various permutations of mac-address to
> > > /boot/{cmdline,config}.txt hasn't worked.
> > The device properties are kernel internals. They are usually derived from
> > configuration informations such as device tree or ACPI.
> > AFAIK there's no way for a user to explicitely set a device property.
> OpenFirmware and UEFI allow properties to be set in the firmware to be
> read into a booting system, and NetBSD already reads FDT data from
> boot media.
>
> It feels like there should be some way to inject additional
> information. Does the rock64 support device tree overlay? If not then
> is there some other similar mechanism already defined that could be
> implemented?
>
> David