Re: [PATCH 3/6] pci, thunder: Add PCIe host controller devicetree bindings

From: Bjorn Helgaas
Date: Thu Sep 25 2014 - 12:17:04 EST

On Thu, Sep 25, 2014 at 1:31 AM, Arnd Bergmann <arnd@xxxxxxxx> wrote:
> On Thursday 25 September 2014 00:37:00 Sunil Kovvuri wrote:
>> On Thu, Sep 25, 2014 at 12:04 AM, Arnd Bergmann <arnd@xxxxxxxx> wrote:
>> > On Wednesday 24 September 2014 23:34:04 Sunil Kovvuri wrote:

>> >> All on-board PCI devices connected to this PCI controller have fixed resources
>> >> and doesn't have to be allocated/reassigned. Some of these devices are
>> >> SRIOV based.
>> >
>> > I think you need to mark the ones that are nonrelocatable with flag
>> > 0x80000000, otherwise the PCI core might decide to reassign them.
>> Is this flag part of DT pci node properties ?
>> I am using IORESOURCE_PCI_FIXED flag. Its there in other patches of
>> the same series.
> Ah, right. I checked the source code again and it seems that we don't handle
> this right at the moment. I think a range that has the nonrelocatable
> flag set should be used for IORESOURCE_PCI_FIXED mappings without any
> host specific code, but that needs to be implemented in common code.

What connection do you envision between nonrelocatable ranges and
IORESOURCE_PCI_FIXED? I don't know what a nonrelocatable range is,
but for IORESOURCE_PCI_FIXED, all I intend is that the PCI core should
not try to assign a different address, e.g., because the BAR is
read-only or because it's a legacy IDE/VGA/etc. range for which there
is no BAR at all.

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