[PATCH 09/24] PCI, powerpc: Register busn_res for root buses

[Yinghai Lu]

On Fri, Feb 24, 2012 at 2:24 PM, Jesse Barnes <jbarnes at virtuousgeek.org> wrote:
> On Thu, 23 Feb 2012 12:51:30 -0800
> Bjorn Helgaas <bhelgaas at google.com> wrote:
>> 2) We already have a way to add resources to a root bus: the
>> pci_add_resource() used to add I/O port and MMIO apertures.  I think
>> it'd be a lot simpler to just use that same interface for the bus
>> number aperture, e.g.,
>>
>>     pci_add_resource(&resources, hose->io_space);
>>     pci_add_resource(&resources, hose->mem_space);
>>     pci_add_resource(&resources, hose->busnr_space);
>>     bus = pci_scan_root_bus(dev, next_busno, pci_ops, sysdata, &resources);
>>
>> This is actually a bit redundant, since "next_busno" should be the
>> same as hose->busnr_space->start.  So if we adopted this approach, we
>> might want to eventually drop the "next_busno" argument.
>
> Yeah that would be nice, the call would certainly make more sense that
> way.

no, I don't think so.

using pci_add_resource will need to create dummy resource abut bus range.

there is lots of pci_scan_root_bus(),  and those user does not bus end
yet before scan.
so could just hide pci_insert_busn_res in pci_scan_root_bus, and
update busn_res end there.

other arch like x86, ia64, powerpc, sparc, will insert exact bus range
between pci_create_root_bus and
pci_scan_child_bus, will not need to update busn_res end.

please check v7 of this patchset.

    	git://git.kernel.org/pub/scm/linux/kernel/git/yinghai/linux-yinghai.git
for-pci-busn-alloc

It should be clean and have minimum lines of change.

Thanks

      Yinghai