[openfirmware] OFW x86 MMU Setup

Andrea r&d4 at dave-tech.it
Thu Jun 19 18:25:52 CEST 2008



Mitch Bradley wrote:
> See http://wiki.laptop.org/go/Forth_Lesson_17
> 

Thanks for the Lesson Mitch!

I successfully enabled MMU but there is still some other problem, I 
think at lower level that this..
At address 0xFFAC0000 (physical or virtual it's the same.. I choose 
phys=virt for ease) I should see my second flash (with IDSEL=1) but I 
still see the first one (which is not a real LPC flash but an LPC dongle)

It's not a problem of physical address conflict (on LPC bus) due the 
fact that I can see the right data at system reset (with a JTAG 
debugger, as previuosly told).
With the same JTAG debugger, if I break the system when OFW is already 
initialized, I have the same problem as above (at physical address 
0xFFAC0000 I see the LPC dongle memory)

It seems that something at lower software level (some msr setup?) "maps" 
0xFFAC0000 somewhere else on LPC bus ('still don't know where.. I will 
investigate..)

Can you tell me where this kind of mappings (if any, of course) are done 
in OFW? (I thinks it's not strictly OFW dependent but only platform 
dependent.. but it will be usefull anyway to know where to look inside 
OFW for the required changes)

Can you also tell me where the MMU mapping of the first flash 
(0xFFBC0000) is done? (maybe I can add my mmu initialization in a better 
place..)

TIA and best regards,

-- 

Andrea

DAVE Srl - Electronics System House
e-mail address: r&d4 at dave-tech.it




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