Subject: [PATCH v2 18/27] arm: plat-orion: add more flexible PCI configuration space read/write functions

From: [email-masked] (Thomas Petazzoni)
Date: Tue, 29 Jan 2013 09:40:03 +0100

Dear Jason Gunthorpe,

On Mon, 28 Jan 2013 12:51:11 -0700, Jason Gunthorpe wrote:
> On Mon, Jan 28, 2013 at 07:56:27PM +0100, Thomas Petazzoni wrote:
> 
> > However, with the usage of the emulated PCI host bridge and emulated
> > PCI-to-PCI bridges, this is not the case: bus number 0 is the emulated
> > bus on which the emulated PCI-to-PCI bridges sit, so from the Linux
> > point of view, the real busses start at bus 1, but from a hardware
> > point of view, they start at bus 0.
> 
> Hum.. This is a bit funny sounding, can you confirm..

Might be yes, but IIRC, when I try to enumerate the devices in the PCIe
interface 0 (from a hardware point of view), passing a bus number of 1
in the PCI configuration space access registers, then it simply doesn't
work.

> The bus number programmed into all the end points must match the Linux
> number. Ie the PCI-E Link Description register of end point devices

What is this PCI-E Link Description register ? Where is it located ?

Thanks,

Thomas
-- 
Thomas Petazzoni, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com