Re: [PATCH 16/16] wl1251: Add sysfs file address for settingpermanent mac address

From: Dan Williams
Date: Mon Oct 28 2013 - 11:30:31 EST

On Mon, 2013-10-28 at 16:04 +0100, Pali RohÃr wrote:
> On Monday 28 October 2013 15:56:55 Johannes Berg wrote:
> > On Mon, 2013-10-28 at 09:46 -0500, Dan Williams wrote:
> > > If the device doesn't actually *have* a permanent MAC
> > > address, then it shouldn't be returning one via ethtool,
> > > and should return an error for ETHTOOL_GPERMADDR.
> >
> > There's currently no provision for that, but I agree it would
> > be better to do so.
> >
> > johannes
> So what to do with devices which has MAC address stored in some
> obscure place and there is userspace binary which can read it?
> I think that there should be some way to tell kernel that *this*
> is the permanent address and it should use it.
> This is reason why I proposed patch which adding sysfs entry for
> setting permanent address from userspace in wl1251 driver.

Ok, so the N900's MAC is stored in the "cal partition", which is a
region of flash exposed to the OS as /dev/mtd1. That also stores the
regulatory domain. Typically userspace binaries are used to pull out
this and other data (see ) which is then used to initialize the device.

Any idea what kernel driver is used to expose the CAL partition
as /dev/mtd1? If it's nothing special maybe a small EEPROM-style driver
could be written to read the relevant areas (and since they don't ever
change, don't need to worry about something else writing at the same


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