[U-Boot-Users] MPC5121 (and MPC5200) ethernet initialization delay

Stefan Roese
2007-12-18T09:03:41Z

On Tuesday 18 December 2007, Wolfgang Denk wrote:
> > autonegotiation only when the ethernet interface is used. Upon TFTP
> > download or something like this. So there should be no delay at all in
> > U-Boot related to this ethernet initialization when you don't use
> > ethernet.
>
> Right, that's how it should be in an ideal world.
>
> However, things are not that simple.
>
> First, the perception that this is how things should work has not been
> there forever. It has riped over time, and older boards / ports do
> things differently.
>
> Second, there are some CPUs / boards where "initializing" the ether-
> net just requires to whack a PY reset or simply take the PHT out of
> reset etc. Autonegotiation then takes place while U-Boot is doing
> other things, and by the time you want to use the Ethernet for a TFTP
> download or so it will be available with no or at least with greatly
> reduced delay.

Right. I know of such ports too and don't see any problems here since no delay
is imposed.

> But there are other implementations which wait for
> autonegotiation to complete.

I don't see a reason why a board should wait for autonegotionation to
complete, when the interface is not used. This should be fixed.

Best regards,
Stefan

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