Re: [ECOS] compile redboot error for AT91EB40

[Mark Salter <msalter at redhat dot com>]

>>>>> Gary Thomas writes:

>> Interestingly, the actual code is..
>> 
>> #ifndef CYGARC_PHYSICAL_ADDRESS
>> # error
>> # define CYGARC_PHYSICAL_ADDRESS(x) (x)
>> #endif
>> 
>> So it looks like whoever wrote the code thinks a sensible fall back is
>> to assume a straight 1-1 mapping. The HAL can override this if
>> required.
>> 
>> May we should just remove the #error line and fix any HALs that are
>> reported not to work?

> I think the #error is serving it's purpose.  IMO, there can be no 
> reasonable fallback and making any assumptions like that is asking
> for trouble.  I didn't write that particular line in that file, but
> I do agree with the idea [of forcing HAL writers to think about what's
> going on]

A reasonable fallback is possible. If MMU is off, its a 1-1 mapping. If
MMU is on, read the appropriate page table entry and construct the phys
address from that. Not fast, but accurate and reliable.

--Mark



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