Index: sys/arm64/cavium/thunder_pcie_common.h
===================================================================
--- sys/arm64/cavium/thunder_pcie_common.h
+++ sys/arm64/cavium/thunder_pcie_common.h
@@ -54,6 +54,7 @@
 
 uint32_t range_addr_is_pci(struct pcie_range *, uint64_t, uint64_t);
 uint32_t range_addr_is_phys(struct pcie_range *, uint64_t, uint64_t);
+uint64_t range_addr_phys_to_pci(struct pcie_range *, uint64_t);
 uint64_t range_addr_pci_to_phys(struct pcie_range *, uint64_t);
 int thunder_common_alloc_msi(device_t, device_t, int, int, int *);
 int thunder_common_alloc_msix(device_t, device_t, int *);
Index: sys/arm64/cavium/thunder_pcie_common.c
===================================================================
--- sys/arm64/cavium/thunder_pcie_common.c
+++ sys/arm64/cavium/thunder_pcie_common.c
@@ -109,3 +109,25 @@
 	return (0);
 }
 
+uint64_t
+range_addr_phys_to_pci(struct pcie_range *ranges, uint64_t phys_addr)
+{
+	struct pcie_range *r;
+	uint64_t offset;
+	int tuple;
+
+	/* Find physical address corresponding to given bus address */
+	for (tuple = 0; tuple < RANGES_TUPLES_MAX; tuple++) {
+		r = &ranges[tuple];
+		if (phys_addr >= r->phys_base &&
+		    phys_addr < (r->phys_base + r->size)) {
+			/* Given phys addr is in this range.
+			 * Translate phys addr to bus addr.
+			 */
+			offset = phys_addr - r->phys_base;
+			return (r->pci_base + offset);
+		}
+	}
+	return (0);
+}
+
Index: sys/arm64/cavium/thunder_pcie_pem.c
===================================================================
--- sys/arm64/cavium/thunder_pcie_pem.c
+++ sys/arm64/cavium/thunder_pcie_pem.c
@@ -83,7 +83,6 @@
 #define	SLIX_S2M_REGX_ACC_SPACING	0x001000000000UL
 #define	SLI_BASE			0x880000000000UL
 #define	SLI_WINDOW_SPACING		0x004000000000UL
-#define	SLI_WINDOW_SIZE			0x0000FF000000UL
 #define	SLI_PCI_OFFSET			0x001000000000UL
 #define	SLI_NODE_SHIFT			(44)
 #define	SLI_NODE_MASK			(3)
@@ -111,9 +110,13 @@
 
 #define	RID_PEM_SPACE		1
 
+static int thunder_pem_activate_resource(device_t, device_t, int, int,
+    struct resource *);
 static struct resource * thunder_pem_alloc_resource(device_t, device_t, int,
     int *, rman_res_t, rman_res_t, rman_res_t, u_int);
 static int thunder_pem_attach(device_t);
+static int thunder_pem_deactivate_resource(device_t, device_t, int, int,
+    struct resource *);
 static int thunder_pem_detach(device_t);
 static uint64_t thunder_pem_config_reg_read(struct thunder_pem_softc *, int);
 static int thunder_pem_link_init(struct thunder_pem_softc *);
@@ -125,6 +128,7 @@
 static void thunder_pem_release_all(device_t);
 static int thunder_pem_release_resource(device_t, device_t, int, int,
     struct resource *);
+static struct rman * thunder_pem_rman(struct thunder_pem_softc *, int);
 static void thunder_pem_slix_s2m_regx_acc_modify(struct thunder_pem_softc *,
     int, int);
 static void thunder_pem_write_config(device_t, u_int, u_int, u_int, u_int,
@@ -147,8 +151,8 @@
 	DEVMETHOD(bus_write_ivar,		thunder_pem_write_ivar),
 	DEVMETHOD(bus_alloc_resource,		thunder_pem_alloc_resource),
 	DEVMETHOD(bus_release_resource,		thunder_pem_release_resource),
-	DEVMETHOD(bus_activate_resource,	bus_generic_activate_resource),
-	DEVMETHOD(bus_deactivate_resource,	bus_generic_deactivate_resource),
+	DEVMETHOD(bus_activate_resource,	thunder_pem_activate_resource),
+	DEVMETHOD(bus_deactivate_resource,	thunder_pem_deactivate_resource),
 	DEVMETHOD(bus_setup_intr,		bus_generic_setup_intr),
 	DEVMETHOD(bus_teardown_intr,		bus_generic_teardown_intr),
 
@@ -164,6 +168,7 @@
     sizeof(struct thunder_pem_softc));
 
 static devclass_t thunder_pem_devclass;
+extern struct bus_space memmap_bus;
 
 DRIVER_MODULE(thunder_pem, pci, thunder_pem_driver, thunder_pem_devclass, 0, 0);
 MODULE_DEPEND(thunder_pem, pci, 1, 1, 1);
@@ -215,6 +220,66 @@
 }
 
 static int
+thunder_pem_activate_resource(device_t dev, device_t child, int type, int rid,
+    struct resource *r)
+{
+	int err;
+	bus_addr_t paddr;
+	bus_size_t psize;
+	bus_space_handle_t vaddr;
+	struct thunder_pem_softc *sc;
+
+	if ((err = rman_activate_resource(r)) != 0)
+		return (err);
+
+	sc = device_get_softc(dev);
+
+	/*
+	 * If this is a memory resource, map it into the kernel.
+	 */
+	if (type == SYS_RES_MEMORY || type == SYS_RES_IOPORT) {
+		paddr = (bus_addr_t)rman_get_start(r);
+		psize = (bus_size_t)rman_get_size(r);
+
+		paddr = range_addr_pci_to_phys(sc->ranges, paddr);
+
+		err = bus_space_map(&memmap_bus, paddr, psize, 0, &vaddr);
+		if (err != 0) {
+			rman_deactivate_resource(r);
+			return (err);
+		}
+		rman_set_bustag(r, &memmap_bus);
+		rman_set_virtual(r, (void *)vaddr);
+		rman_set_bushandle(r, vaddr);
+	}
+	return (0);
+}
+
+/*
+ * This function is an exact copy of nexus_deactivate_resource()
+ * Keep it up-to-date with all changes in nexus. To be removed
+ * once bus-mapping interface is developed.
+ */
+static int
+thunder_pem_deactivate_resource(device_t bus, device_t child, int type, int rid,
+    struct resource *r)
+{
+	bus_size_t psize;
+	bus_space_handle_t vaddr;
+
+	psize = (bus_size_t)rman_get_size(r);
+	vaddr = rman_get_bushandle(r);
+
+	if (vaddr != 0) {
+		bus_space_unmap(&memmap_bus, vaddr, psize);
+		rman_set_virtual(r, NULL);
+		rman_set_bushandle(r, 0);
+	}
+
+	return (rman_deactivate_resource(r));
+}
+
+static int
 thunder_pem_identify(device_t dev)
 {
 	struct thunder_pem_softc *sc;
@@ -304,14 +369,6 @@
 		return retval;
 	}
 
-	retval = bus_space_map(sc->reg_bst, sc->sli_window_base,
-	    SLI_WINDOW_SIZE, 0, &sc->pem_sli_base);
-	if (retval) {
-		device_printf(sc->dev,
-		    "Unable to map RC%d pem_addr base address", sc->id);
-		return (ENOMEM);
-	}
-
 	/* To support 32-bit PCIe devices, set S2M_REGx_ACC[BA]=0x0 */
 	for (i = 0; i < SLI_ACC_REG_CNT; i++) {
 		thunder_pem_slix_s2m_regx_acc_modify(sc, sc->sli_group, i);
@@ -355,24 +412,30 @@
 
 	/* Calculate offset */
 	offset = (bus << PEM_BUS_SHIFT) | (slot << PEM_SLOT_SHIFT) |
-	    (func << PEM_FUNC_SHIFT) | reg;
+	    (func << PEM_FUNC_SHIFT);
 	t = sc->reg_bst;
 	h = sc->pem_sli_base;
 
+	bus_space_map(sc->reg_bst, sc->sli_window_base + offset,
+	    PCIE_REGMAX, 0, &h);
+
 	switch (bytes) {
 	case 1:
-		data = bus_space_read_1(t, h, offset);
+		data = bus_space_read_1(t, h, reg);
 		break;
 	case 2:
-		data = le16toh(bus_space_read_2(t, h, offset));
+		data = le16toh(bus_space_read_2(t, h, reg));
 		break;
 	case 4:
-		data = le32toh(bus_space_read_4(t, h, offset));
+		data = le32toh(bus_space_read_4(t, h, reg));
 		break;
 	default:
-		return (~0U);
+		data = ~0U;
+		break;
 	}
 
+	bus_space_unmap(sc->reg_bst, h, PCIE_REGMAX);
+
 	return (data);
 }
 
@@ -393,23 +456,28 @@
 
 	/* Calculate offset */
 	offset = (bus << PEM_BUS_SHIFT) | (slot << PEM_SLOT_SHIFT) |
-	    (func << PEM_FUNC_SHIFT) | reg;
+	    (func << PEM_FUNC_SHIFT);
 	t = sc->reg_bst;
 	h = sc->pem_sli_base;
 
+	bus_space_map(sc->reg_bst, sc->sli_window_base + offset,
+	    PCIE_REGMAX, 0, &h);
+
 	switch (bytes) {
 	case 1:
-		bus_space_write_1(t, h, offset, val);
+		bus_space_write_1(t, h, reg, val);
 		break;
 	case 2:
-		bus_space_write_2(t, h, offset, htole16(val));
+		bus_space_write_2(t, h, reg, htole16(val));
 		break;
 	case 4:
-		bus_space_write_4(t, h, offset, htole32(val));
+		bus_space_write_4(t, h, reg, htole32(val));
 		break;
 	default:
-		return;
+		break;
 	}
+
+	bus_space_unmap(sc->reg_bst, h, PCIE_REGMAX);
 }
 
 static struct resource *
@@ -421,35 +489,28 @@
 	struct resource *res;
 	device_t parent_dev;
 
-	switch (type) {
-	case SYS_RES_IOPORT:
-		rm = &sc->io_rman;
-		break;
-	case SYS_RES_MEMORY:
-		rm = &sc->mem_rman;
-		break;
-	default:
+	rm = thunder_pem_rman(sc, type);
+	if (rm == NULL) {
 		/* Find parent device. On ThunderX we know an exact path. */
 		parent_dev = device_get_parent(device_get_parent(dev));
 		return (BUS_ALLOC_RESOURCE(parent_dev, dev, type, rid, start,
 		    end, count, flags));
 	};
 
-	if ((start == 0UL) && (end == ~0UL)) {
-		device_printf(dev,
-		    "Cannot allocate resource with unspecified range\n");
-		goto fail;
-	}
-
-	/* Translate PCI address to host PHYS */
-	if (range_addr_is_pci(sc->ranges, start, count) == 0)
-		goto fail;
-	start = range_addr_pci_to_phys(sc->ranges, start);
+	/*
+	 * We might get PHYS addresses here inherited from EFI.
+	 * Convert to PCI if necessary.
+	 */
+	if ((start != 0UL) || (end != ~0UL)) {
+		if (range_addr_is_phys(sc->ranges, start, count)) {
+			start = range_addr_phys_to_pci(sc->ranges, start);
 			end = start + count - 1;
+		}
+	}
 
 	if (bootverbose) {
 		device_printf(dev,
-		    "rman_reserve_resource: start=%#lx, end=%#lx, count=%#lx\n",
+		    "thunder_pem_alloc_resource: start=%#lx, end=%#lx, count=%#lx\n",
 		    start, end, count);
 	}
 
@@ -493,6 +554,22 @@
 	return (rman_release_resource(res));
 }
 
+static struct rman *
+thunder_pem_rman(struct thunder_pem_softc *sc, int type)
+{
+
+	switch (type) {
+	case SYS_RES_IOPORT:
+		return (&sc->io_rman);
+	case SYS_RES_MEMORY:
+		return (&sc->mem_rman);
+	default:
+		break;
+	}
+
+	return (NULL);
+}
+
 static int
 thunder_pem_probe(device_t dev)
 {
@@ -519,6 +596,9 @@
 	struct thunder_pem_softc *sc;
 	int error;
 	int rid;
+	int tuple;
+	uint64_t base, size;
+	struct rman *rman;
 
 	sc = device_get_softc(dev);
 	sc->dev = dev;
@@ -591,16 +671,42 @@
 	sc->ranges[0].size = PCI_MEMORY_SIZE;
 	sc->ranges[0].phys_base = sc->sli_window_base + SLI_PCI_OFFSET +
 	    sc->ranges[0].pci_base;
-	rman_manage_region(&sc->mem_rman, sc->ranges[0].phys_base,
-	    sc->ranges[0].phys_base + sc->ranges[0].size - 1);
+	sc->ranges[0].flags = SYS_RES_MEMORY;
 
 	/* Fill IO window */
 	sc->ranges[1].pci_base = PCI_IO_BASE;
 	sc->ranges[1].size = PCI_IO_SIZE;
 	sc->ranges[1].phys_base = sc->sli_window_base + SLI_PCI_OFFSET +
 	    sc->ranges[1].pci_base;
-	rman_manage_region(&sc->io_rman, sc->ranges[1].phys_base,
-	    sc->ranges[1].phys_base + sc->ranges[1].size - 1);
+	sc->ranges[1].flags = SYS_RES_IOPORT;
+
+	for (tuple = 0; tuple < RANGES_TUPLES_MAX; tuple++) {
+		base = sc->ranges[tuple].pci_base;
+		size = sc->ranges[tuple].size;
+		if (size == 0)
+			continue; /* empty range element */
+
+		rman = thunder_pem_rman(sc, sc->ranges[tuple].flags);
+		if (rman != NULL)
+			error = rman_manage_region(rman, base,
+			    base + size - 1);
+		else
+			error = EINVAL;
+		if (error) {
+			device_printf(dev,
+			    "rman_manage_region() failed. error = %d\n", error);
+			rman_fini(&sc->mem_rman);
+			return (error);
+		}
+		if (bootverbose) {
+			device_printf(dev,
+			    "\tPCI addr: 0x%jx, CPU addr: 0x%jx, Size: 0x%jx, Flags:0x%jx\n",
+			    sc->ranges[tuple].pci_base,
+			    sc->ranges[tuple].phys_base,
+			    sc->ranges[tuple].size,
+			    sc->ranges[tuple].flags);
+		}
+	}
 
 	if (thunder_pem_init(sc)) {
 		device_printf(dev, "Failure during PEM init\n");