On Thu, Sep 05, 2013 at 10:26:59AM +0200, Thomas Petazzoni wrote: > > One simpler solution for them could be to slightly modify the boot loader > > so that it sets the MAC address on the two ethernet controllers prior to > > boot. Then your code which checks if a MAC is already set will simply > > work. > > This works when the network driver is compiled 'statically' inside the > kernel. When compiled as a module, then the gatable clock of the > network interface will be gated at the end of the kernel boot, before > the mvneta module is probe. And gating the network interface clocks > means that it will loose its state, including its MAC address. So it's > not an entirely perfect solution either, but I admit that on such > platforms, the network driver is most likely compiled statically, so it > would probably suit the needs of most people. Agreed. > Note that this can be done without doing any change in the bootloader. > For example, on a Mirabox, you can do: > > mw.l 0xD0072414 0x5C93; mw.l 0xD0072418 0xF0AD4E01; mw.l 0xD0076414 0x5C94; mw.l 0xD0076418 0xF0AD4E01; bootm > > to boot your kernel. This will program the MAC addresses for both > network interfaces in the network controllers, so that when booting > Linux, you get: > > [ 42.122881] mvneta d0070000.ethernet eth0: Using hardware mac address f0:ad:4e:01:5c:93 > [ 42.385398] mvneta d0074000.ethernet eth1: Using hardware mac address f0:ad:4e:01:5c:94 > > You add that to your default U-Boot boot script, and that's it, you > have stable MAC addresses. Hmmm that's quite interesting. Unfortunately I don't see an easy way to make this directly rely on the ethaddr/eth1addr so that end users can simply cut-n-paste a few lines into the u-boot config. But anyway that can be useful. > > A last one would be to have the mvneta module accept an array of addresses > > as a module parameter. This way it would just require a minor change in the > > kernel's cmdline to pass the MAC addresses. I remember seeing this in the > > past, I don't remember the platform (maybe the NSLU2 but I could be wrong). > > The situation of module parameters to pass MAC addresses was a bit > fuzzy. There was once a proposal to add a generic kernel parameter to > do this, but it was rejected by David Miller (I believe not on specific > implementation details, but on the general idea). However, there are > numerous drivers in the tree that do provide a custom module parameter > to set MAC addresses. Yes, I remember using this with the sunhme driver many years ago when we did not have access to the onboard rom to retrieve the MAC address. > However, with the above suggestion of U-Boot scripting, I believe we > have a relatively easy solution for people to use. We could provide a script to do it more conveniently for the user :-) Best regards, Willy -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html