On Fri, Jul 17, 2020 at 10:08 AM Andrew Lunn <[email protected]> wrote: > > On Fri, Jul 17, 2020 at 08:58:26AM -0700, Tim Harvey wrote: > > Greetings, > > > > We make embedded boards that often have on-board PCIe based NIC's that > > have MAC addresses stored in an EEPROM (not within NIC's NVRAM). I've > > struggled with a way to have boot firmware assign the mac's via > > device-tree and I find that only some drivers support getting the MAC > > from device-tree anyway. > > > > What is the appropriate way to assign vendor MAC's to a NIC from boot > > firmware, or even in userspace? > > Hi Tim > > From user space you can always use > > ip link set address XX:XX:XX:XX:XX:XX dev enp42s0 > > But that assumes the MAC driver actually supports setting its MAC > address. As with getting the MAC address from DT, this is also > optional in the driver. But i guess it is more often implemented. > > I don't know of any universal method. So i think you probably do need > to work on each of the MAC drivers you are interested in, and add DT > support. >
Andrew, Doing it from device-tree becomes very complicated for example in the case where a NIC is behind a on-board switch and the PCI bus topology changes if an add-in card on a port before the NIC ends up having a switch on it (as the NIC's bus/device changes). Such a situation requires that boot firmware enumerates the PCI bus and rebuild's the nested topology to properly place/update the 'local-mac-address' property. I realize in userspace you can use 'ip' to set a hwaddr I'm just not clear if there is a common pattern like a udev hook or something that helps assign MAC addr that might be present in a common location. Maybe the norm is to skip assigning board vendor mac's and let the drivers choose a random addr? Tim
