Hi Wouter,
On Friday 04 September 2009 14:34:49 Wouter Eckhardt wrote:
I'm making quite good progress porting U-Boot (2009.03) to my custom PPC440GX board.
2009.03 is already "old". I suggest you use the 2009.09 release.
Right now I'm trying to solve a little problem I have with board start-up time when I enable ECC on DDR RAM. The board literally takes minutes to initialize RAM. I'm guessing this is due to the fact that ecc_init() fills the entire RAM (the comments already suggest some performance enhancements can be implemented).
d-cache is the solution.
I've tried solving this by shortly enabling the D cache before writing RAM and disabling the D cache afterwards, using the function change_tlb(). However, if I enable the D cache using change_tlb() and supply it with the same parameters ecc_init() receives, I get an exception when change_tlb() invalidates the cache.
Did you flush the caches? You need to be careful here, when changing TLB attributes.
Which DDR2 init code are you using btw? A specific custom code with fixed settings? Or the 4xx common SPD code? I suggest you take a look at the common DDR2 code (44x_spd_ddr2.c). ECC handling is done there already with caches enabled. This should give you an idea.
Cheers, Stefan
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