Re: Modpost warning on Alchemy

[Sergei Shtylyov <sshtylyov@ru.mvista.com>]

Maciej W. Rozycki wrote:

>>>>Of course it will.  It shall work with whatever physical address space is
>>>>supported by your MMU.  As long as the MMU is handled correctly that is,
>>>>but I guess I may have omitted this clarification as obvious.

>>>   Even on a CPU with 36-bit physical address? ;-)

>>   WTF... I know I've typed "32-bit CPU"! :-/

>  It does not matter.  The physical address of an I/O resource can be 

    Believe me, it does in *this* case. :-)

> treated as a cookie that is converted, typically though an MMU, to another 
> cookie that can be used with {read,write}{b,w,l}().  Of course you may 
> have troubles ioremap()ping say 4GB of I/O space on a processor with a
> 32-bit virtual address space, but that is a corner case and typically your 
> I/O space will be sparsely occupied.

    It is exactly this case.

>  On a MIPS32 processor you have 512MB of KSEG0/1 unmapped virtual address 
> space available for I/O devices located within the first 512MB of the 

    PCI config. space is mapped at 0x600000000, well beyond KGSEG0/1.

> physical address space plus 1GB of KSEG2 mapped virtual address space 
> available for I/O devices located anywhere in the physical address space.  
> That gives you from 1GB to 1.5GB of virtual address space for I/O which is 
> enough for all the usual cases.

    This case is not usual. :-)

>   Maciej

    Thanks for wasting time on my education about MIPS. ;-)

WBR, Sergei