powerpc/PCI: Clip bridge windows to fit in upstream windows

Every PCI-PCI bridge window should fit inside an upstream bridge window
because orphaned address space is unreachable from the primary side of the
upstream bridge.  If we inherit invalid bridge windows that overlap an
upstream window from firmware, clip them to fit and update the bridge
accordingly.

[bhelgaas: changelog]
Link: https://bugzilla.kernel.org/show_bug.cgi?id=85491
Reported-by: Marek Kordik <[email protected]>
Fixes: 5b28541 ("PCI: Restrict 64-bit prefetchable bridge windows to 64-bit resources")
Signed-off-by: Yinghai Lu <[email protected]>
Signed-off-by: Bjorn Helgaas <[email protected]>
CC: Benjamin Herrenschmidt <[email protected]>
CC: Paul Mackerras <[email protected]>
CC: Michael Ellerman <[email protected]>
CC: Gavin Shan <[email protected]>
CC: Anton Blanchard <[email protected]>
CC: Sebastian Ott <[email protected]>
CC: Wei Yang <[email protected]>
CC: Andrew Murray <[email protected]>
CC: [email protected]

Author: Yinghai Lu

arch/powerpc/kernel/pci-common.c

@@ -1184,6 +1184,8 @@ static void pcibios_allocate_bus_resources(struct pci_bus *bus)
 			 pr, (pr && pr->name) ? pr->name : "nil");
 
 		if (pr && !(pr->flags & IORESOURCE_UNSET)) {
+			struct pci_dev *dev = bus->self;
+
 			if (request_resource(pr, res) == 0)
 				continue;
 			/*
@@ -1193,6 +1195,11 @@ static void pcibios_allocate_bus_resources(struct pci_bus *bus)
 			 */
 			if (reparent_resources(pr, res) == 0)
 				continue;
+
+			if (dev && i < PCI_BRIDGE_RESOURCE_NUM &&
+			    pci_claim_bridge_resource(dev,
+						i + PCI_BRIDGE_RESOURCES) == 0)
+				continue;
 		}
 		pr_warning("PCI: Cannot allocate resource region "
 			   "%d of PCI bridge %d, will remap\n", i, bus->number);
@@ -1401,7 +1408,10 @@ void pcibios_claim_one_bus(struct pci_bus *bus)
 				 (unsigned long long)r->end,
 				 (unsigned int)r->flags);
 
-			pci_claim_resource(dev, i);
+			if (pci_claim_resource(dev, i) == 0)
+				continue;
+
+			pci_claim_bridge_resource(dev, i);
 		}
 	}