From mboxrd@z Thu Jan  1 00:00:00 1970
From: andy@warmcat.com (Andy Green)
Date: Fri, 18 Mar 2011 09:13:04 +0000
Subject: [RFC PATCH 2/5] OMAP2+: add cpu id register to MAC address helper
In-Reply-To: <4D831D4B.8090407@nokia.com>
References: <20110312224440.27728.60593.stgit@otae.warmcat.com>
	<20110312225047.27728.1835.stgit@otae.warmcat.com>
	<4D831D4B.8090407@nokia.com>
Message-ID: <4D832220.9030704@linaro.org>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On 03/18/2011 08:52 AM, Somebody in the thread at some point said:

>> +	/* mark it as not multicast and outside official 80211 MAC namespace */
>> +
>> +	mac[0] = (mac[0]&  ~1) | 2;

> so here lies the answer to my question "From where do you get the MAC" :)
>
> Is there a guarantee that this MAC will work in all Ethernet setups?

Yeah it's in 80211 spec.  You have to buy the spec, I can't point you to 
it directly, but here is the wikipedia article showing the structure

http://en.wikipedia.org/wiki/MAC_address#Address_details

the random mac addresses generated by the kernel also use this scheme.

-Andy