On Wed, May 2, 2012 at 2:22 PM, Bjorn Helgaas <bhelgaas@xxxxxxxxxx> wrote:
> On Sun, Mar 18, 2012 at 11:42 PM, Yinghai Lu <yinghai@xxxxxxxxxx> wrote:
>> Set up iobusn_resource tree, and register bus number range to it.
>> Later when need to find bus range, will try to allocate from the tree
>>
>> Need to test on arches other than x86. esp for ia64 and powerpc that support
>> more than on peer root buses.
>>
>> The patches need to apply to linux v3.3 + pci-next and
>> [PATCH -v3] PCI: pci_host_bridge related cleanup
>>
>> could be found at:
>> git://git.kernel.org/pub/scm/linux/kernel/git/yinghai/linux-yinghai.git for-pci-busn-alloc
>
> I started merging this series, but I didn't get very far. I stopped
> at the "resources: Add probe_resource()" patch because I don't think
> that interface makes sense yet. My work-in-progress is at
> git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci.git on the
> topic/yinghai-busn-alloc branch.
>
> I *could* merge that branch, but I don't think they fix anything (that
> would come in the later patches), and there are still some issues in
> my mind.
>
> - I think we really want a [bus 00-ff] resource for each *domain*,
> with each host bridge in the domain requesting part of that range. I
> think these patches only track bus number usage within each host
> bridge, and I'm not sure there's any place we would detect conflicts
> between host bridges.
I updated the patch set a bit. now it have domain busn_res.
It could detect the conflicts. later could add code to resolve the conflicts.
int pci_bus_insert_busn_res(struct pci_bus *b, int bus, int bus_max)
{
struct resource *res = &b->busn_res;
struct resource *parent_res;
int ret;
res->start = bus;
res->end = bus_max;
res->flags = IORESOURCE_BUS;
if (!pci_is_root_bus(b))
parent_res = &b->parent->busn_res;
else {
parent_res = get_pci_domain_busn_res(pci_domain_nr(b));
res->flags |= IORESOURCE_PCI_FIXED;
}
ret = insert_resource(parent_res, res);
dev_printk(KERN_DEBUG, &b->dev,
"busn_res: %pR %s inserted under %s %pR\n",
res, ret ? "can not be" : "is",
pci_is_root_bus(b) ? "domain":"", parent_res);
return ret;
}
>
> - I think I made a mistake in the pci_create_root_bus() and
> pci_scan_root_bus() interfaces. They currently take a bus number and
> a list of resources, and we expect the arch to include the bus number
> aperture in the list. The bus number argument should have been
> replaced with a bus number aperture resource. The bus number aperture
> is essential, while the MMIO/IO aperture list may be empty. And it's
> stupid to pass both the starting bus number and a bus resource that
> contains the starting bus number. Fixing this would make some of
> these patches quite a bit simpler.
Yes, could try to address that later to make it more clean.
> - In some of the arches (sparc, powerpc), you added a bus number
> resource right next to existing first_busno, last_busno fields. So
> now that data lives two places, which will bite us later.
then later we should kill first_busno and last_busno in those arches.
Yinghai
--
To unsubscribe from this list: send the line "unsubscribe linux-pci" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
