diff --git a/arch/tile/include/asm/pci.h b/arch/tile/include/asm/pci.h
index 553b7ff..1ab2a58 100644
--- a/arch/tile/include/asm/pci.h
+++ b/arch/tile/include/asm/pci.h
@@ -128,15 +128,10 @@ static inline void pci_iounmap(struct pci_dev *dev, void __iomem *addr) {}
 #define        TILE_PCI_MEM_MAP_BASE_OFFSET    (1ULL << CHIP_PA_WIDTH())

 /*
- * End of the PCI memory resource.
+ * Start of the PCI memory resource, which starts at the end of the
+ * maximum system physical RAM address.
  */
-#define        TILE_PCI_MEM_END        \
-               ((1ULL << CHIP_PA_WIDTH()) + TILE_PCI_BAR_WINDOW_TOP)
-
-/*
- * Start of the PCI memory resource.
- */
-#define        TILE_PCI_MEM_START      (TILE_PCI_MEM_END - TILE_PCI_BAR_WINDOW_SIZE)
+#define        TILE_PCI_MEM_START      (1ULL << CHIP_PA_WIDTH())

 /*
  * Structure of a PCI controller (host bridge) on Gx.
@@ -161,6 +156,7 @@ struct pci_controller {

        uint64_t mem_offset;    /* cpu->bus memory mapping offset. */

+       int first_busno;
        int last_busno;

        struct pci_ops *ops;
@@ -169,6 +165,7 @@ struct pci_controller {
        int irq_intx_table[4];

        struct resource mem_space;
+       char mem_name[32];

        /* Address ranges that are routed to this controller/bridge. */
        struct resource mem_resources[3];
@@ -179,14 +176,6 @@ extern gxio_trio_context_t trio_contexts[TILEGX_NUM_TRIO];

 extern void pci_iounmap(struct pci_dev *dev, void __iomem *);

-extern void
-pcibios_resource_to_bus(struct pci_dev *dev, struct pci_bus_region *region,
-                       struct resource *res);
-
-extern void
-pcibios_bus_to_resource(struct pci_dev *dev, struct resource *res,
-                       struct pci_bus_region *region);
-
 /*
  * The PCI address space does not equal the physical memory address
  * space (we have an IOMMU). The IDE and SCSI device layers use this
diff --git a/arch/tile/kernel/pci_gx.c b/arch/tile/kernel/pci_gx.c
index 27f7ab0..7d854b5 100644
--- a/arch/tile/kernel/pci_gx.c
+++ b/arch/tile/kernel/pci_gx.c
@@ -96,21 +96,6 @@ static struct pci_ops tile_cfg_ops;
 /* Mask of CPUs that should receive PCIe interrupts. */
 static struct cpumask intr_cpus_map;

-/* PCI I/O space support is not implemented. */
-static struct resource pci_ioport_resource = {
-       .name   = "PCI IO",
-       .start  = 0,
-       .end    = 0,
-       .flags  = IORESOURCE_IO,
-};
-
-static struct resource pci_iomem_resource = {
-       .name   = "PCI mem",
-       .start  = TILE_PCI_MEM_START,
-       .end    = TILE_PCI_MEM_END,
-       .flags  = IORESOURCE_MEM,
-};
-
 /*
  * We don't need to worry about the alignment of resources.
  */
@@ -440,6 +425,23 @@ out:
                controller->last_busno = 0xff;
                controller->ops = &tile_cfg_ops;

+               /*
+                * The PCI memory resource is located above the PA space.
+                * For every host bridge, the BAR window or the MMIO aperture
+                * is in range [3GB, 4GB - 1] of a 4GB space beyond the
+                * PA space.
+                */
+
+               controller->mem_offset = TILE_PCI_MEM_START +
+                       (i * TILE_PCI_BAR_WINDOW_TOP);
+               controller->mem_space.start = controller->mem_offset +
+                       TILE_PCI_BAR_WINDOW_TOP - TILE_PCI_BAR_WINDOW_SIZE;
+               controller->mem_space.end = controller->mem_offset +
+                       TILE_PCI_BAR_WINDOW_TOP - 1;
+               controller->mem_space.flags = IORESOURCE_MEM;
+               snprintf(controller->mem_name, sizeof(controller->mem_name),
+                        "PCI mem domain %d", i);
+               controller->mem_space.name = controller->mem_name;
        }

        return num_rc_controllers;
@@ -588,6 +590,7 @@ int __init pcibios_init(void)
 {
        resource_size_t offset;
        LIST_HEAD(resources);
+       int next_busno;
        int i;

        tile_pci_init();
@@ -628,7 +631,7 @@ int __init pcibios_init(void)
        msleep(250);

        /* Scan all of the recorded PCI controllers.  */
-       for (i = 0; i < num_rc_controllers; i++) {
+       for (next_busno = 0, i = 0; i < num_rc_controllers; i++) {
                struct pci_controller *controller = &pci_controllers[i];
                gxio_trio_context_t *trio_context = controller->trio;
                TRIO_PCIE_INTFC_PORT_CONFIG_t port_config;
@@ -843,13 +846,14 @@ int __init pcibios_init(void)
                 * The memory range for the PCI root bus should not overlap
                 * with the physical RAM
                 */
-               pci_add_resource_offset(&resources, &iomem_resource,
-                                       1ULL << CHIP_PA_WIDTH());
+               pci_add_resource_offset(&resources, &controller->mem_space,
+                                       controller->mem_offset);

-               bus = pci_scan_root_bus(NULL, 0, controller->ops,
+               controller->first_busno = next_busno;
+               bus = pci_scan_root_bus(NULL, next_busno, controller->ops,
                                        controller, &resources);
                controller->root_bus = bus;
-               controller->last_busno = bus->subordinate;
+               next_busno = bus->subordinate + 1;

        }

@@ -1011,20 +1015,9 @@ alloc_mem_map_failed:
 }
 subsys_initcall(pcibios_init);

-/*
- * PCI scan code calls the arch specific pcibios_fixup_bus() each time it scans
- * a new bridge. Called after each bus is probed, but before its children are
- * examined.
- */
+/* Note: to be deleted after Linux 3.6 merge. */
 void __devinit pcibios_fixup_bus(struct pci_bus *bus)
 {
-       struct pci_dev *dev = bus->self;
-
-       if (!dev) {
-               /* This is the root bus. */
-               bus->resource[0] = &pci_ioport_resource;
-               bus->resource[1] = &pci_iomem_resource;
-       }
 }

 /*
@@ -1124,7 +1117,10 @@ void __iomem *ioremap(resource_size_t phys_addr, unsigned long size)
 got_it:
        trio_fd = controller->trio->fd;

-       offset = HV_TRIO_PIO_OFFSET(controller->pio_mem_index) + phys_addr;
+       /* Convert the resource start to the bus address offset. */
+       start = phys_addr - controller->mem_offset;
+
+       offset = HV_TRIO_PIO_OFFSET(controller->pio_mem_index) + start;

        /*
         * We need to keep the PCI bus address's in-page offset in the VA.
@@ -1172,11 +1168,11 @@ static int __devinit tile_cfg_read(struct pci_bus *bus,
        void *mmio_addr;

        /*
-        * Map all accesses to the local device (bus == 0) into the
+        * Map all accesses to the local device on root bus into the
         * MMIO space of the MAC. Accesses to the downstream devices
         * go to the PIO space.
         */
-       if (busnum == 0) {
+       if (pci_is_root_bus(bus)) {
                if (device == 0) {
                        /*
                         * This is the internal downstream P2P bridge,
@@ -1205,11 +1201,11 @@ static int __devinit tile_cfg_read(struct pci_bus *bus,
        }

        /*
-        * Accesses to the directly attached device (bus == 1) have to be
+        * Accesses to the directly attached device have to be
         * sent as type-0 configs.
         */

-       if (busnum == 1) {
+       if (busnum == (controller->first_busno + 1)) {
                /*
                 * There is only one device off of our built-in P2P bridge.
                 */
@@ -1303,11 +1299,11 @@ static int __devinit tile_cfg_write(struct pci_bus *bus,
        u8 val_8 = (u8)val;

        /*
-        * Map all accesses to the local device (bus == 0) into the
+        * Map all accesses to the local device on root bus into the
         * MMIO space of the MAC. Accesses to the downstream devices
         * go to the PIO space.
         */
-       if (busnum == 0) {
+       if (pci_is_root_bus(bus)) {
                if (device == 0) {
                        /*
                         * This is the internal downstream P2P bridge,
@@ -1336,11 +1332,11 @@ static int __devinit tile_cfg_write(struct pci_bus *bus,
        }

        /*
-        * Accesses to the directly attached device (bus == 1) have to be
+        * Accesses to the directly attached device have to be
         * sent as type-0 configs.
         */

-       if (busnum == 1) {
+       if (busnum == (controller->first_busno + 1)) {
                /*
                 * There is only one device off of our built-in P2P bridge.
                 */
diff --git a/arch/tile/kernel/setup.c b/arch/tile/kernel/setup.c
index 2b8b689..6a649a4 100644
--- a/arch/tile/kernel/setup.c
+++ b/arch/tile/kernel/setup.c
@@ -1536,8 +1536,7 @@ static struct resource code_resource = {

 /*
  * On Pro, we reserve all resources above 4GB so that PCI won't try to put
- * mappings above 4GB; the standard allows that for some devices but
- * the probing code trunates values to 32 bits.
+ * mappings above 4GB.
  */
 #if defined(CONFIG_PCI) && !defined(__tilegx__)
 static struct resource* __init
@@ -1584,7 +1583,6 @@ static int __init request_standard_resources(void)
        int i;
        enum { CODE_DELTA = MEM_SV_INTRPT - PAGE_OFFSET };

-       iomem_resource.end = -1LL;
 #if defined(CONFIG_PCI) && !defined(__tilegx__)
        insert_non_bus_resource();
 #endif
