On Jan 29, 2008, at 8:20 AM, Laurent Lagrange wrote:

Hello,

I have a MPC8641 based board. I try to use the two PCIe controllers.  
My
firmware configures (physically) the PCI buses as follow:

------------------+
MPC8641 PCIe 1	|	bus 1		+--------------+
			| --------------> | PCI device 0 |
	BUS 0		|			+--------------+
- - - - - - - - - +
MPC8641 PCIe 2	|	bus 3		+--------------+
			| --------------> | PCI device 1 |
	BUS 2		|			+--------------+
------------------+

I launch the Linux image (2.6.23.9). During the Kernel PCI  
configuration,
buses behind the 2nd MPC8641 PCIe are skipped because its primary  
bus don't
start at bus number 0. The kernel reconfigure the primary bus number  
of the
MPC8641 PCIe 2 controller from 2 to 0.

I can patch the kernel to work with my firmware but I don't know if  
my PCI
configuration is the good one.

What is the common way to configure the PCI for Linux when a new  
controller
is found: start the bus number to 0 or to the last bus number + 1?

Linux now has the concept of PCI domains so each controller is a new  
domain and thus the first bus should be 0 in each domain.  (at least  
that's the "normal" way we handle things).

- k