Re: [PATCH v12 10/12] PCI: Assign unassigned bus resources in pci_scan_root_bus()

[Bjorn Helgaas]

On Tue, Sep 23, 2014 at 7:18 PM, Liviu Dudau <liviu@xxxxxxxxxxx> wrote:
> On Tue, Sep 23, 2014 at 08:01:12PM +0100, Liviu Dudau wrote:
>> If the firmware has not assigned all the bus resources and
>> we are not just probing the PCIe busses, it makes sense to
>> assign the unassigned resources in pci_scan_root_bus().
>>
>> Cc: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
>> Cc: Arnd Bergmann <arnd@xxxxxxxx>
>> Cc: Jason Gunthorpe <jgunthorpe@xxxxxxxxxxxxxxxxxxxx>
>> Cc: Rob Herring <robh+dt@xxxxxxxxxx>
>> Signed-off-by: Liviu Dudau <Liviu.Dudau@xxxxxxx>
>> ---
>>  drivers/pci/probe.c | 3 +++
>>  1 file changed, 3 insertions(+)
>>
>> diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
>> index ef891d2..508cf61 100644
>> --- a/drivers/pci/probe.c
>> +++ b/drivers/pci/probe.c
>> @@ -1953,6 +1953,9 @@ struct pci_bus *pci_scan_root_bus(struct device *parent, int bus,
>>       if (!found)
>>               pci_bus_update_busn_res_end(b, max);
>>
>> +     if (!pci_has_flag(PCI_PROBE_ONLY))
>> +             pci_assign_unassigned_bus_resources(b);
>> +
>>       pci_bus_add_devices(b);
>>       return b;
>>  }
>> --
>> 2.1.0
>>
>
> Bjorn,
>
> If you are OK with this patch, can you let me know how do you feel about
> making pci_scan_root_bus() set up the bus->msi pointer as well?

I'm not opposed to it, but I have the same question as for setting up
the domain: how does pci_scan_root_bus() learn what to assign to
bus->msi?  It currently only gets a "void *sysdata" so there's no
obvious place to put it there.  You could add a pcibios interface to
retrieve it, I suppose, but I'm starting to get uncomfortable with
adding more of those because we have such a mess of them already.

Bjorn

> Side note: I don't know exactly how to do it now, but setting bus->msi is
> needed by platforms that are based on my patches and want to use MSI,
> otherwise they have to open code pci_scan_root_bus() to set it. I haven't
> made any attempts to do it in this series as the GICv2m patches are not
> ready yet, but I can see the need arriving soon.
>
> Best regards,
> Liviu
>
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>
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