[U-Boot-Users] Re: Using u-boot as application-firmware upgrader / Performing logical operations?

[Martin Egholm Nielsen]

Hi,

>>Ohh, of course - that's the way I'll do it. That is, saving it in an 
>>environment-variable.
>>In order to change it from Linux, access to the NOR-flash is required, 
>>right?! I'm not quite sure I have that?
> Of course yoiu have - through the MTD layer (and  the  stuff  in  the
> tools/env directory).
Ok, then I'm sure my board's kernel dosn't detect the NOR. The only 
mtd-messages I get concerns the NAND.

>>Dooh! I forgot that tftp use UDP. Then "responding" means one correct 
>>response from the tftp-server within x seconds. I guess there is a 
> Define "correct" response. What about time outs later?
That would be ok.
What I want is u-boot to try to see if there is a tftp-server connected 
(meaning that someone is trying to upgrade the firmware). If not: 
continue rapidly into Linux and launch the application. I don't wanna 
spend too much time hanging in u-boot if the reboot were, say, due to a 
powerfailure.

>>Hence, what I want is perhaps (?) environment variables controlling how 
>>how many retries, the interval between each "T"-try, and the amount of 
>>tries before abondoning...
> Perhaps.
:-)
I know that is exactly what I'm looking for...

>>>>Hence, what I'd like, was a way to determine if the download was 
>>>>successfull - e.g. by comparing the return value for the command.
>>>You can do that easily - just not by timeout only.
>>How?
> Use the return code in some conditional, like an "if tftp ... ;  then
> ... ; fi" or some "tftp ... && ..." - whatever you use in other shell
> scripts, too.
>>Is there a document describing these scripting possibilities?
> man sh? Ok, ok, the hush  shell  does  not  provide  every  bell  and
> whistle  the  bash  has,  but  it's  a pretty complete thing. See the
> busybox docs for more information.
Ahaaaaa!!! There we have it!
If one does not know the name of it - one (me) will look under
"5.11. U-Boot Scripting Capabilities" (which is empty).

and not in the correct (faq-) section:
"14.2.10. How the Command Line Parsing Works"

That title is not intuitive to me. I read: "How the 'Old, simple command 
line parser' works".

IMHO that beautiful section shouldn't be in a FAQ... :o)

Now, I just need to recompile with the enabling parameter (CFG_HUSH_PARSER).

BR,
  Martin