Re: [XenPPC] [rfc] Serial discovery.

[Jimi Xenidis <jimix@xxxxxxxxxxxxxx>]

On May 4, 2006, at 8:43 AM, Maria Butrico wrote:

> I was hoping to bring in and use as much as possible linux'  
> pmac_zilog.h that defines read and write regs inlined functions  
> that only use readb and writeb.
yes if you can copy the entire file and subtly twist it so that is  
still can be matched to the original that would be handy, see xen/ 
arch/ppc/mpic.c
> As for the NS driver I would wish for something a bit more robust  
> that testing the value of io_base.
I agree, but I rather just leave the NS driver alone, IMHO its pretty  
finicky already.
>   My changes to the serial code discovery atm simply set io_base to  
> be the sum of the value we squirrel in isa_io_base and the device  
> address.
Thats fine, perhaps we should just find the location of ISA  
independent of the UART?  But, thats code for another day.
>   This would cause the ns device driver on ppc to do always read/ 
> writeb.  Not that is matters on ppc becuase inb and outb in fact  
> add the two anyway.
> In general I would prefer to see logic in the serial discovery code  
> that decides if the device is on the isa bus, sets or checks  
> isa_io_base, and flags the device as one that should use inb/outb,  
> rather than this funky thing based on the value of io_base.
Wellm I think that is what they do, but instead of a flag whey see if  
the absolute pointer is !NULL then use it.
One thing we cannot do is assume that if there is an isa_io_base that  
the NS is on the ISA (I know I'm stating the obvious, but IMHO it  
bears stating)
-JX


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