On Tue, Dec 30, 2014 at 10:58:00PM +0100, Arnd Bergmann wrote:

On Tuesday 30 December 2014 13:28:33 Rob Herring wrote:

quoted

+	list_for_each_entry(win, res, list) {
+		struct resource *parent, *res = win->res;
+
+		switch (resource_type(res)) {
+		case IORESOURCE_IO:
+			parent = &ioport_resource;
+			err = pci_remap_iospace(res, iobase);
+			if (err) {
+				dev_warn(dev, "error %d: failed to map resource %pR\n",
+					 err, res);
+				continue;
+			}
+			break;
+		case IORESOURCE_MEM:
+			parent = &iomem_resource;
+			res_valid |= !(res->flags & IORESOURCE_PREFETCH);
+
+			writel(res->start >> 28, PCI_IMAP(mem));
+			writel(PHYS_OFFSET >> 28, PCI_SMAP(mem));
+			mem++;
+
+			break;
+		case IORESOURCE_BUS:
+		default:
+			continue;
+		}
+
+		err = devm_request_resource(dev, parent, res);
+		if (err)
+			goto out_release_res;
+	}

I wonder if we should also request the physical resource for the I/O space
window to have it show up in /proc/iomem. We are rather inconsistent in this
regard between drivers.

I'd like that.  We are inconsistent, but I think it's useful to have this
information in /proc/iomem.  After all, it is physical address space that
we can't use for anything else, so I guess you could argue that it's
actually a bug to omit it.

quoted

+	pci_add_flags(PCI_ENABLE_PROC_DOMAINS);
+	pci_add_flags(PCI_REASSIGN_ALL_BUS | PCI_REASSIGN_ALL_RSRC);
+
+	bus = pci_scan_root_bus(&pdev->dev, 0, &pci_versatile_ops, &sys, &pci_res);
+	if (!bus)
+		return -ENOMEM;
+
+	pci_fixup_irqs(pci_common_swizzle, of_irq_parse_and_map_pci);
+	pci_assign_unassigned_bus_resources(bus);
+
+	return 0;

One general question, mainly for Bjorn: pci_scan_root_bus adds all the devices
at the Linux driver level by calling pci_bus_add_devices(), but then we call
pci_fixup_irqs and pci_assign_unassigned_bus_resources after that, which will
change the devices again. Is this how it's meant to work? How do we ensure
that we have the correct irq number and resources by the time we enter the
probe() function of the PCI device driver that gets bound to a device here?

Nope, that isn't how it's meant to work.  After pci_bus_add_devices()
completes, drivers can be already bound to the device, and the PCI core
should keep its mitts off things the driver could be using.  But I think
we've had this problem for a long time, and I haven't looked at it recently
to see how hard it would be to fix.

Bjorn