[U-Boot] setting u-boot params based on serial number

[Wolfgang Denk]

Dear "David Collier",

In message <memo.20091023175206.2092W at postmaster+dexdyne.com.cix.co.uk> you wrote:
> 
> I have a batch of boards in production.
> 
> say serial numbers 1 to 50
> 
> I want to set the 2 mac address, and the ip address so that the last few
> digits match the serial number.
> 
> can I do this easily with some sort of u-boot script? Or can I run an app
> I write myself in C or whatever, and get it to do setenv commands?

You can do this using the "setexpr" command, with the restriction that
you cannot easily get leading zeros in the strings to fill tem up for
the requested length, but for the usage you mention it does not
matter. Also, you cannot easily convert to hex number, if that would
be needed.

Example:

	=> print serial#
	serial#=12851192

Extract last 2 digits into vatiable "tmp" (note: serial# must consist
of digits only):

	=> setex tmp ${serial#} % 100
	=> print tmp 
	tmp=92

Set MAC and IP address as requested:

	=> setenv ip_base 192.168.3.
	=> setenv mac_base ce:94:6b:3a:db:

	=> setenv ipaddr ${ip_base}${tmp}
	=> print ipaddr
	ipxxx=192.168.3.92
	=> setenv ethaddr ${mac_base}${tmp}
	=> print ethaddr
	ethaddr=ce:94:6b:3a:db:92

> AVR32, if it matters

It does not matter. This works on all boards / architectures. You just
have to enable CONFIG_CMD_SETEXPR in your board configuration.


Best regards,

Wolfgang Denk

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