[U-Boot-Users] Does Uboot do lowlevel clock settings if it is in RAM?

[Jerry Van Baren]

arun c wrote:
> Hi,
> 
> Sorry for the confusion,I mean i did not port uboot completely.
> 
> with a working uboot i mean, a uboot that able to access RAM,
> serial port etc. ie basic functionalities only.
> 
> My case is like this
> 1)on an old board we have a working uboot(Everything fine).
> 
> 2)we replaced the RAM on the old board(same mapping but
> different manufacturer)
> 
> 3)we did not modify  uboot(Thats why we are setting the timings
>  in a debugger(CCS), downloading uboot to RAM and running it
> there.)
> 
> 4)we are doing this with an assumption that uboot not change
>  clocks if it knows its running from RAM
> 
> But we are observing clock changes.
> 
> Does uboot change clock if its running from RAM?
> 
> Regards
> 
> Arun

Hi Arun,

It shouldn't, but you have to check your code and fix it if it does.  We 
cannot say for sure, not having your code.  Running from RAM is a 
"non-standard" configuration so it may or may not be supported on your 
board.  Sounds like not.  On the positive side, you have the source 
(including examples of proper support), so you can add the support.

Theoretically, adding the support is easy because you simply #ifdef out 
the SDRAM initialization.  In practice, there are lots of sharp edges to 
cut yourself on, which is why it is a non-standard configuration.

Best regards,
gvb