Dear =?ISO-8859-1?Q?Matthias_Wei=DFer?=,
In message 4C63ACA6.6080303@arcor.de you wrote:
Am 12.08.2010 09:54, schrieb Frans Meulenbroeks:
2010/8/12 Matthias Weißerweisserm@arcor.de:
Why not store the size of the environment sector as env variable? The size should be only needed for storing the environment and not for loading (as it is terminated by a '\0'). So we could load the environment, check for "env_size" and if its not there take the value from fw_env.config
Currently the crc of the environment is calculated and if it does not match with the stored crc the default environment is used. For determining the crc the size is needed so storing the size in the env creates some form of catch-22. Of course the code could be modified to first peek at the unverified env to find the size. That is a different approach. Imho not too neat.
Was this an off-list reply? I cannot see any trace of this message on the list.
Please always keep the list on Cc: !
I see. I was thinking that the CRC is only calculated over the environment until the '\0' end mark is reached. But after checking my environment code I see that the CRC is calculated over the whole sector.
For the sake of simplicity it should be possible to assume that the CRC is correct, look up the env_size variable, and then check the CRC with the length thus found.
Wrt the format: I understood from the mail from Reinhard that the way the env is stored is going to change anyway. I saw the patches of Wolfgang pass by, but didn't have time to study them yet.
The external storage format will NOT change. Compatibility with existing code (not only in U-Boot) is a major concern of all such changes.
I also didn't go that deep into Wolfgangs patches but from what I understand the "on disk format" will not change. Will it?
No, it ill remain exactly the same.
Maybe the size could be added at the end of the environment (behind the '\0'). So we wouldn't loose compatibility.
It would add new issues, like when the envrionment is filing up.
Best regards,
Wolfgang Denk