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Subject: Re: questions: second of the 2 pcie controllers does not scan the bus.
From: Scott Wood <scottwood@freescale.com>
To: Ruchika <ruchika.k@servergy.com>
Date: Mon, 9 Dec 2013 16:50:19 -0600
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On Fri, 2013-12-06 at 18:48 -0600, Ruchika wrote:
> Hi,
> I am working with an p4080 based board. I am trying to get 2 PCIE 
> controllers probed properly.
> 
> In uboot I have no problems scanning and discovering what is connected 
> to both controllers/PCI bridges.
> 
> For both PCIE1/2 uboot sets up the Primary, secondary and Subordinate 
> bus numbers to 0,1,1 respectively.
> 
> When linux boots up and probes the controllers, PCIE1 is probed and the 
> bridge scanned properly but PCIE2 is probed at the bridge but not 
> attempted a scan.
> I see this message
> "pci 0001:02:00.0: bridge configuration invalid ([bus 01-01]), reconfiguring
> "
> 
> I updated uboot to set the secondary and subordinate numbers to 2 (left 
> the primary number to 0) and a subsequent kernel boot scanned the bus 
> for PCIE2 successfully.
> I found these numbers to be very critical since the device tree blob 
> (bus-range) for pci is also based off these.
> 
> I'd like to get a good fix rather than the uboot hack and get better 
> understanding of the problem. If there are any pointers someone could 
> provide it would be awesome.

This is the code that prints that:

        /* Check if setup is sensible at all */
        if (!pass &&
            (primary != bus->number || secondary <= bus->number ||
             secondary > subordinate)) {
                dev_info(&dev->dev, "bridge configuration invalid ([bus %02x-%0
                         secondary, subordinate);
                broken = 1;
        }

Start by printing out more information to determine which of those
checks is failing (e.g. what is primary and bus->number).  If it turns
out that U-Boot is configuring the PCI bus incorrectly, send e-mail to
the U-Boot list.  Be sure to mention what version of Linux and U-Boot
you're using.

-Scott