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From: Kumar Gala <galak@kernel.crashing.org>
To: Laurent Lagrange <lagrange@fr.oleane.com>
In-Reply-To: <000501c86282$2a5ba9e0$a501a8c0@GEGE6600V>
Subject: Re: PCI configuration with multiple PCI controllers
References: <000501c86282$2a5ba9e0$a501a8c0@GEGE6600V>
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Date: Wed, 30 Jan 2008 08:24:05 -0600
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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