Subject: Re: [PATCH 08/18] PCI, powerpc: Register busn_res for root buses

From: Benjamin Herrenschmidt <[email-masked]>
Date: Tue, 03 Apr 2012 07:22:47 +1000

On Mon, 2012-04-02 at 05:19 -0500, Milton Miller wrote:
> 
> In the POWER3 era we had several boxes that split the pci bus number
> space across domains and RTAS used the bus number to find the correct
> PHB.   This contineed to the first RS64 boxes.  By S80 and RS64-III
> it was obvious that we didn't have enough numbers to continue this
> ilusion and we added the presently used RTAS calls that take the pci
> domain as well as bus, device, and function numbers.
> 
> The bus numbers split across pci domains started with the F50
> F50 chrp 32 bit platforms. 

Ok, so old CHRPs would have a split as well...

I think the best is to honor the bus-range property of the PHB as min &
max values, and if we feel a need to allow the kernel to assign busses
beyond that, we can always quirk the appropriate platform code.

Cheers,
Ben.