[U-Boot-Users] Ethernet port

[Wolfgang Denk]

In message <1190149063.4516.9.camel at aeglos.sweden.atmel.com> you wrote:
>
> > It is a terrible bad idea to set the IP address and especially the MAC
> > address of your board in the config file, as then all your boards will
> > share the same address, which will cause only trouble.
> > 
> > DO NOT DO THIS!!!
> 
> Unless you use this functionality to simplify factory programming of the
> device.

It's still a very stupid thing to do, as you buy your own convenience
at the cost of your customers - it's they who will have the problems,
not  you,  obviously.  And  it's  trivial  to  set  up  a  production
envrionment  where  each and every board has it's own specific serial
number, MAC address atf. in the U-Boot environment.

Don't tell me it could not be done, or would be too complicated. It's
all there, just use it.

> By having a compile time setup of ethaddr/ipaddr/serverip, you can
> easily connect to a production PC using a twisted cable.

It is NOT necessary to do this at compile time.

> If this "feature" is used, it must be possible to reconfigure
> the ethaddr/ipaddr combination to something unique.
> You do not want to ship this to end customers.

Then you have to make ethaddr and serial# unprotected, which IMHO  is
a bad idea either. I don't want to have users messing around with the
serial  number.  If  you intend for such a setup, you should at least
use the CONFIG_OVERWRITE_ETHADDR_ONCE feature.

> An autoscript at the production PC can do this as part of the production
> programming.

There are much easier ways which  don't  require  console  access  or
booting  the system. See "board/tqm8xx/load_sernum_ethaddr.c" for one
example wher ethis information can be written by the same programming
sequence that programs the U-Boot image - it just programs some small
data block in a second step.

> it is probably advisable to disallow booting the linux kernel if
> the ethaddr/ipaddr has not changed.

Too complicated, and not necessary.

Best regards,

Wolfgang Denk

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