Wolfgang Denk wrote:
In message 408CAD48.4020004@intracom.gr you wrote:
IMHO the gd data are pretty much useless in a complicated environment.
Agreed. But that's not what they were meant for.
The gd data is intended to store the absolute minimum of rwritable date which is really unavoidable to be stored in global variables until the RAM has been initialized and a standard data segment and stack are available.
For example when you have multiple network interfaces you have no information which network interface was used to obtain the configuration, which was it's ethernet address etc.
This is something which can easily be done after relocation to RAM, so there is no need to use gd for this purpose.
For me the gd is usefull only for the simple case of most boards with one network interface, fixed clock etc.
No. This is NOT the intention.
For anything more complicated is better to parse the environment variables.
In the end we will probably have something like bi_recs ...
Why don't we just add the missing information to the environment variables?
Because you cannot access envrionment in very early initialization steps, or you have to do it in a very slow way (like reading byte by byte from serial EEPROM), which would horribly slow down boot.
Correct.
But I'm not talking about the early initialization.
I'm talking about how the loaded image/kernel gets access to the information.
At that point the variables are placed in RAM, and can contain every info that is present in the gd structure.
U-boot can continue to use the gd structure, but the application can access all it's configuration from the environment variables.
For example we can fill a environment variable with the system clock value at the later stages of initialization.
Best regards,
Wolfgang Denk
Regards
Pantelis