1 files changed, 116 insertions, 47 deletions

diff --git a/arch/powerpc/kernel/pci-common.c b/arch/powerpc/kernel/pci-common.c
index 8c02709..01ce8c3 100644
--- a/arch/powerpc/kernel/pci-common.c
+++ b/arch/powerpc/kernel/pci-common.c
@@ -780,11 +780,6 @@ static void __devinit fixup_resource(struct resource *res, struct pci_dev *dev)
 
 	res->start = (res->start + offset) & mask;
 	res->end = (res->end + offset) & mask;
-
-	pr_debug("PCI:%s            %016llx-%016llx\n",
-		 pci_name(dev),
-		 (unsigned long long)res->start,
-		 (unsigned long long)res->end);
 }
 
 
@@ -830,6 +825,11 @@ static void __devinit pcibios_fixup_resources(struct pci_dev *dev)
 			 (unsigned int)res->flags);
 
 		fixup_resource(res, dev);
+
+		pr_debug("PCI:%s            %016llx-%016llx\n",
+			 pci_name(dev),
+			 (unsigned long long)res->start,
+			 (unsigned long long)res->end);
 	}
 
 	/* Call machine specific resource fixup */
@@ -838,58 +838,127 @@ static void __devinit pcibios_fixup_resources(struct pci_dev *dev)
 }
 DECLARE_PCI_FIXUP_HEADER(PCI_ANY_ID, PCI_ANY_ID, pcibios_fixup_resources);
 
-static void __devinit __pcibios_fixup_bus(struct pci_bus *bus)
+/* This function tries to figure out if a bridge resource has been initialized
+ * by the firmware or not. It doesn't have to be absolutely bullet proof, but
+ * things go more smoothly when it gets it right. It should covers cases such
+ * as Apple "closed" bridge resources and bare-metal pSeries unassigned bridges
+ */
+static int __devinit pcibios_uninitialized_bridge_resource(struct pci_bus *bus,
+							   struct resource *res)
 {
 	struct pci_controller *hose = pci_bus_to_host(bus);
 	struct pci_dev *dev = bus->self;
+	resource_size_t offset;
+	u16 command;
+	int i;
 
-	pr_debug("PCI: Fixup bus %d (%s)\n", bus->number, dev ? pci_name(dev) : "PHB");
+	/* We don't do anything if PCI_PROBE_ONLY is set */
+	if (ppc_pci_flags & PPC_PCI_PROBE_ONLY)
+		return 0;
 
-	/* Fixup PCI<->PCI bridges. Host bridges are handled separately, for
-	 * now differently between 32 and 64 bits.
-	 */
-	if (dev != NULL) {
-		struct resource *res;
-		int i;
+	/* Job is a bit different between memory and IO */
+	if (res->flags & IORESOURCE_MEM) {
+		/* If the BAR is non-0 (res != pci_mem_offset) then it's probably been
+		 * initialized by somebody
+		 */
+		if (res->start != hose->pci_mem_offset)
+			return 0;
 
-		for (i = 0; i < PCI_BUS_NUM_RESOURCES; ++i) {
-			if ((res = bus->resource[i]) == NULL)
-				continue;
-			if (!res->flags)
-				continue;
-			if (i >= 3 && bus->self->transparent)
-				continue;
-			/* On PowerMac, Apple leaves bridge windows open over
-			 * an inaccessible region of memory space (0...fffff)
-			 * which is somewhat bogus, but that's what they think
-			 * means disabled...
-			 *
-			 * We clear those to force them to be reallocated later
-			 *
-			 * We detect such regions by the fact that the base is
-			 * equal to the pci_mem_offset of the host bridge and
-			 * their size is smaller than 1M.
-			 */
-			if (res->flags & IORESOURCE_MEM &&
-			    res->start == hose->pci_mem_offset &&
-			    res->end < 0x100000) {
-				printk(KERN_INFO
-				       "PCI: Closing bogus Apple Firmware"
-				       " region %d on bus 0x%02x\n",
-				       i, bus->number);
-				res->flags = 0;
-				continue;
-			}
+		/* The BAR is 0, let's check if memory decoding is enabled on
+		 * the bridge. If not, we consider it unassigned
+		 */
+		pci_read_config_word(dev, PCI_COMMAND, &command);
+		if ((command & PCI_COMMAND_MEMORY) == 0)
+			return 1;
 
-			pr_debug("PCI:%s Bus rsrc %d %016llx-%016llx [%x] fixup...\n",
-				 pci_name(dev), i,
-				 (unsigned long long)res->start,\
-				 (unsigned long long)res->end,
-				 (unsigned int)res->flags);
+		/* Memory decoding is enabled and the BAR is 0. If any of the bridge
+		 * resources covers that starting address (0 then it's good enough for
+		 * us for memory
+		 */
+		for (i = 0; i < 3; i++) {
+			if ((hose->mem_resources[i].flags & IORESOURCE_MEM) &&
+			    hose->mem_resources[i].start == hose->pci_mem_offset)
+				return 0;
+		}
+
+		/* Well, it starts at 0 and we know it will collide so we may as
+		 * well consider it as unassigned. That covers the Apple case.
+		 */
+		return 1;
+	} else {
+		/* If the BAR is non-0, then we consider it assigned */
+		offset = (unsigned long)hose->io_base_virt - _IO_BASE;
+		if (((res->start - offset) & 0xfffffffful) != 0)
+			return 0;
+
+		/* Here, we are a bit different than memory as typically IO space
+		 * starting at low addresses -is- valid. What we do instead if that
+		 * we consider as unassigned anything that doesn't have IO enabled
+		 * in the PCI command register, and that's it.
+		 */
+		pci_read_config_word(dev, PCI_COMMAND, &command);
+		if (command & PCI_COMMAND_IO)
+			return 0;
+
+		/* It's starting at 0 and IO is disabled in the bridge, consider
+		 * it unassigned
+		 */
+		return 1;
+	}
+}
+
+/* Fixup resources of a PCI<->PCI bridge */
+static void __devinit pcibios_fixup_bridge(struct pci_bus *bus)
+{
+	struct resource *res;
+	int i;
+
+	struct pci_dev *dev = bus->self;
 
-			fixup_resource(res, dev);
+	for (i = 0; i < PCI_BUS_NUM_RESOURCES; ++i) {
+		if ((res = bus->resource[i]) == NULL)
+			continue;
+		if (!res->flags)
+			continue;
+		if (i >= 3 && bus->self->transparent)
+			continue;
+
+		pr_debug("PCI:%s Bus rsrc %d %016llx-%016llx [%x] fixup...\n",
+			 pci_name(dev), i,
+			 (unsigned long long)res->start,\
+			 (unsigned long long)res->end,
+			 (unsigned int)res->flags);
+
+		/* Perform fixup */
+		fixup_resource(res, dev);
+
+		/* Try to detect uninitialized P2P bridge resources,
+		 * and clear them out so they get re-assigned later
+		 */
+		if (pcibios_uninitialized_bridge_resource(bus, res)) {
+			res->flags = 0;
+			pr_debug("PCI:%s            (unassigned)\n", pci_name(dev));
+		} else {
+
+			pr_debug("PCI:%s            %016llx-%016llx\n",
+				 pci_name(dev),
+				 (unsigned long long)res->start,
+				 (unsigned long long)res->end);
 		}
 	}
+}
+
+static void __devinit __pcibios_fixup_bus(struct pci_bus *bus)
+{
+	struct pci_dev *dev = bus->self;
+
+	pr_debug("PCI: Fixup bus %d (%s)\n", bus->number, dev ? pci_name(dev) : "PHB");
+
+	/* Fixup PCI<->PCI bridges. Host bridges are handled separately, for
+	 * now differently between 32 and 64 bits.
+	 */
+	if (dev != NULL)
+		pcibios_fixup_bridge(bus);
 
 	/* Additional setup that is different between 32 and 64 bits for now */
 	pcibios_do_bus_setup(bus);