[U-Boot] PPC440GX: DDR ECC init time.

[Wouter Eckhardt]

Hi all,

I'm making quite good progress porting U-Boot (2009.03) to my custom
PPC440GX board. 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).

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. Commenting out that
call (just to try it) solves the exception problem, but the RAM
initialization time does not really seem to improve.

What can I do to speed up this ECC initialization? Have I forgotten
something when I try to enable the D cache? Any suggestions are welcome.

Kind regards,
Met vriendelijke groet,
Wouter Eckhardt
Engineer
wouter.eckhardt at prodrive.nl
tel. +31 40 2676187
Prodrive B.V.
Postbus 28030
5602 JA Eindhoven
Ekkersrijt 5025
5692 EB Son
The Netherlands
tel. +31 40 2676200
fax: +31 40 2676201
www.prodrive.nl


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