[U-Boot] environment variables crc

[Gerrit Van Damme]

Dear Wolgang Denk,

Wolfgang Denk wrote:
> Dear Gerrit Van Damme,
>
> In message <49ED809D.5030702 at mgb-tech.com> you wrote:
>   
>> The saveenv command doesn't work for me because then the default env 
>> variables are stored and this is what I want to avoid.
>>     
>
> Then change the environment before running saveenv? Or even better -
> adjust the default environment so it matches your needs. What's the
> problem?
>   
Thing is I would like to bypass the Uboot commands.
Maybe I'll explain my problem a little more detailed.
We're using a taskit panelcard based on the Atmel at91sam9261. Atmel 
provides some boot assistant software (SAM-BA) which allows you to 
create images and clone them.
Now we set up a complete system on the taskit and now we want to start 
cloning. We were succesfull on this part the only thing is the MAC 
address sits also in this flash image.
We created a script which gets the original MAC address from the board. 
Inserts it in the flash image file and then writes it to the board.
And then we got the CRC error because we didn't recalculate the CRC. We 
want to include the CRC calculation in our SAM-BA script so that 
everything is already set and we can skip the
Uboot part. This is why I needed some specific info on the CRC calculation.

But if I'm unable to calculate the CRC  I'll have to go for a second 
(Uboot) script to set up the environment. But it wont be highly 
appreciated by our production team :-)
>   
>> It's already a good thing that I can see that the first 4 bytes really 
>> look like the CRC of the environment. So this was really helpfull info.
>> Now you tell me it's calculated using the environment. In the source 
>> code I found the env variables crc calculated for a size of ENV_SIZE, but
>> I was unable to see how it was defined. Do you have more info on this?
>>     
>
> Hmmm... "grep" is your friend.
>   
Indeed that's true... but only if you're already friends with "Linux"
>   
>> Is the environment data (for crc calculation) terminated by a certain 
>> char (or sequence of chars) ?
>>     
>
> No. Not for CRC calculation.
>
> Best regards,
>
> Wolfgang Denk
>
>   
Thanks for your answer Wolfgang

Regards,

Gerrit