[U-Boot-Users] Re: U-Boot for AT91RM9200DK

Steven Scholz steven.scholz at imc-berlin.de
Fri Oct 24 16:41:54 CEST 2003


Rick,

>>>>Should we put all the init code into cpu/at91rm9200/{start.S} and use CONFIG_ 
>>>>and CFG_?
>>>
>>>  I'd put it all in start.S and not define any CONFIG for it.
>>
>>Hmm. But my boards has a completly different clocking scheme!
>>For instance: I use an 16MHz external clock oszillator. The eval board has an 
>>18,xxx MHz crystal...
>>So we need at least some CFG_'s for clock configuration.
> 
>   I have completely different crystals than the AT91RM9200DK.  Do
> you want me to put my clock settings in u-boot?  How about the 500
> different AT91RM9200 boards that get designed this year?  Do you want
> their specific stuff in u-boot?
> 
>   By necessity u-boot is already nearing #ifdef hell because it
> supports so many devel boards (which is good).  If we all threw
> our specific board design stuff in there, I don't think anyone in
> their right mind would use u-boot.

Probably a misunderstanding!

How I am supposed to setup clocks and PLLs and serial port in the AT91RM9200 if 
I don't have any informations?

I thought of something like this in start.S:

#ifdef CFG_USE_EXT_CRYSTAL
	enable_main_oscillator;
#endif

/* set up PLL */
	set PLLA to CFG_PLLAR
	set PLLB to CFG_PLLBR
...

And the user just has to define CFG_USE_EXT_CRYSTAL, CFG_PLLAR etc in his board 
specific header file. Of course without the need to submit his configuration to 
the U-Boot CVS.

Ok?

Steven





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