Hello Kenji-san,
* Kenji Kaneshige <kaneshige.kenji@xxxxxxxxxxxxxx>:
> Alex Chiang wrote:
> > We have a nice interface for re-scanning a PCI bus which will
> > discover newly added devices, add them to the device tree, and
> > enable them properly.
> >
> > Ensure that the bridge resources are properly sized and assigned
> > during the rescan.
> >
> > Signed-off-by: Alex Chiang <achiang@xxxxxx>
> > ---
> >
> > drivers/pci/hotplug-pci.c | 16 ++++++++++++----
> > 1 files changed, 12 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/pci/hotplug-pci.c b/drivers/pci/hotplug-pci.c
> > index 4d4a644..33ab2d2 100644
> > --- a/drivers/pci/hotplug-pci.c
> > +++ b/drivers/pci/hotplug-pci.c
> > @@ -6,13 +6,21 @@
> >
> > unsigned int __devinit pci_do_scan_bus(struct pci_bus *bus)
> > {
> > - unsigned int max;
> > + unsigned int max, pass;
> > + struct pci_dev *dev;
> >
> > max = pci_scan_child_bus(bus);
> >
> > - /*
> > - * Make the discovered devices available.
> > - */
> > + for (pass=0; pass < 2; pass++)
> > + list_for_each_entry(dev, &bus->devices, bus_list) {
> > + if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE ||
> > + dev->hdr_type == PCI_HEADER_TYPE_CARDBUS)
> > + if (pass && dev->subordinate)
> > + pci_bus_size_bridges(dev->subordinate);
> > + }
> > +
> > + pci_bus_assign_resources(bus);
> > + pci_enable_bridges(bus);
> > pci_bus_add_devices(bus);
>
> The "for (pass=0; pass <2; pass++)" loop doesn't look necessary.
Yes, I don't know why I had it in there originally. I can remove
that.
> And I'm worrying that your change have some bad effect to the
> existing user of pci_do_scan_bus(). Did you confirm that?
I hadn't gotten around to verifying/fixing existing callers of
pci_do_scan_bus yet. I was focusing on the core first.
There aren't too many callers, but unfortunately, I don't have
any hardware that actually uses the existing drivers.
I seem to recall that your machines support shpchp. Would you
mind testing this patch and telling me if your machine still
behaves properly?
I looked at shpchp_configure_device and I think that simply
scanning the device's parent bus should work.
Thanks.
/ac
diff --git a/drivers/pci/hotplug/shpchp_pci.c b/drivers/pci/hotplug/shpchp_pci.c
index aa315e5..7e8457b 100644
--- a/drivers/pci/hotplug/shpchp_pci.c
+++ b/drivers/pci/hotplug/shpchp_pci.c
@@ -110,11 +110,7 @@ int __ref shpchp_configure_device(struct slot *p_slot)
return -EINVAL;
}
- num = pci_scan_slot(parent, PCI_DEVFN(p_slot->device, 0));
- if (num == 0) {
- ctrl_err(ctrl, "No new device found\n");
- return -ENODEV;
- }
+ pci_do_scan_bus(parent);
for (fn = 0; fn < 8; fn++) {
dev = pci_get_slot(parent, PCI_DEVFN(p_slot->device, fn));
@@ -126,40 +122,10 @@ int __ref shpchp_configure_device(struct slot *p_slot)
pci_dev_put(dev);
continue;
}
- if ((dev->hdr_type == PCI_HEADER_TYPE_BRIDGE) ||
- (dev->hdr_type == PCI_HEADER_TYPE_CARDBUS)) {
- /* Find an unused bus number for the new bridge */
- struct pci_bus *child;
- unsigned char busnr, start = parent->secondary;
- unsigned char end = parent->subordinate;
- for (busnr = start; busnr <= end; busnr++) {
- if (!pci_find_bus(pci_domain_nr(parent),
- busnr))
- break;
- }
- if (busnr > end) {
- ctrl_err(ctrl,
- "No free bus for hot-added bridge\n");
- pci_dev_put(dev);
- continue;
- }
- child = pci_add_new_bus(parent, dev, busnr);
- if (!child) {
- ctrl_err(ctrl, "Cannot add new bus for %s\n",
- pci_name(dev));
- pci_dev_put(dev);
- continue;
- }
- child->subordinate = pci_do_scan_bus(child);
- pci_bus_size_bridges(child);
- }
program_fw_provided_values(dev);
pci_dev_put(dev);
}
- pci_bus_assign_resources(parent);
- pci_bus_add_devices(parent);
- pci_enable_bridges(parent);
return 0;
}
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