1 files changed, 116 insertions, 47 deletions

diff --git a/arch/powerpc/kernel/pci-common.c b/arch/powerpc/kernel/pci-common.c
index 8c0270929cc0..01ce8c38bae6 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);