[U-Boot-Users] 5282 u-boot shadowing

NZG ngustavson at emacinc.com
Tue Mar 15 18:50:34 CET 2005

I'm working on getting u-boot up and running, pre-loader less, for the 5282.
I've run into a few issues with the way things are currently done and I wanted 
to run some alternatives past the list to make sure I'm not violating any 
u-boot standards.

1. The m68k code currently copies it's flash to DRAM at it's final location, 
then jumps to DRAM.
To do it this way, the DRAM cannot be located at 0, as initializing the RAM 
there will shadow the Flash before the code has been copied. 

Therefore the RAM can either be
1. moved to another location - I have implemented a version that does this, 
and it starts up ok, but the RAM winds up being at location 0xff000000, 
rather than 0. Is this going to work? Or am I violating some important 

2. Copied before the address of the RAM is set, then just drop the RAM 
directly on top of it. I haven't tried this yet, but it may be a better 
solution as I'm getting the feeling that u-boot is expecting RAM at 0.
Is this correct?


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