[U-Boot-Users] [PATCH] m68k fix for Ethernet Buffers at address 0

Wolfgang Denk wd at denx.de
Sat Jul 14 01:21:08 CEST 2007


In message <1defaf580707121538y65db81c9y748f14b9a62ea31b at mail.gmail.com> you wrote:
>
> When I submitted the macb ethernet driver, which works on both avr32
> and at91sam926x devices, for inclusion in the LInux kernel, I was told
> to remove the mac address from the platform data. This was because ARM

So far this is most probably correct.

> relied on u-boot initializing the mac address of all ethernet
> controllers before booting Linux, so AVR32 should do the same as well.

This is definitely not correct. U-Boot's position about this is very
clear, and has been for a long time. This is actually a FAQ, please
look it up.

> So I did this and added some code to the avr32 board setup to
> initialize the mac address registers as a temporary measure until I
> could be sure that u-boot did in fact always set up the mac address on
> all interfaces.

It will never do that.

> Now, it seems like the situation is:
>   a) Other architectures rely on mac registers being initialized by
> u-boot as well.
>   b) This is not how things are supposed to work.

b)

> I'd be happy to go back to passing mac addresses through the tagged
> list (in fact, u-boot never stopped doing that on avr32) but this
> needs to be resolved on ARM before I can change the driver.

The thing is that the ARM folks don't want o  see  MAC  addresses  in
ATAGs  either.  Don't  ask  me  why  - if they use this mechanism for
passing h/w related information  around  that  would  seem  the  most
logical approach to me, too. But they don't want it.

And we are as stubborn as them: we don't want to initialize h/w we
didn't use.

<asbestos>
The Right Thing (TM) would of course be to get rid of all this  ATAGs
stuff  on  ARM  and  use  a  proper  device tree there, too, like the
PowerPC folks have been doing for such a long time. And on  MIPS  and
all the other systems, too.
</asbestos>

[He, I'm leaving for vacation, so I won't suffer from the fires of
the flame war I just started :-) ]

Best regards,

Wolfgang Denk

-- 
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