diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 9b80428..8e4b789 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -276,6 +276,13 @@ config PCI_DOMAINS_GENERIC
 config PCI_SYSCALL
 	def_bool PCI
 
+config PCI_MMCONFIG
+	def_bool y
+	select PCI_ECAM
+	select HAVE_PCI_ECAM
+	select GENERIC_PCI_ECAM
+	depends on ACPI
+
 source "drivers/pci/Kconfig"
 source "drivers/pci/pcie/Kconfig"
 source "drivers/pci/hotplug/Kconfig"
diff --git a/arch/arm64/kernel/pci.c b/arch/arm64/kernel/pci.c
index 4095379..d1629dc 100644
--- a/arch/arm64/kernel/pci.c
+++ b/arch/arm64/kernel/pci.c
@@ -11,12 +11,15 @@
  */
 
 #include <linux/acpi.h>
+#include <linux/ecam.h>
 #include <linux/init.h>
 #include <linux/io.h>
 #include <linux/kernel.h>
 #include <linux/mm.h>
+#include <linux/of_address.h>
 #include <linux/of_pci.h>
 #include <linux/of_platform.h>
+#include <linux/pci-acpi.h>
 #include <linux/slab.h>
 
 #include <asm/pci-bridge.h>
@@ -43,31 +46,251 @@ resource_size_t pcibios_align_resource(void *data, const struct resource *res,
  */
 int pcibios_add_device(struct pci_dev *dev)
 {
-	dev->irq = of_irq_parse_and_map_pci(dev, 0, 0);
+	if (acpi_disabled)
+		dev->irq = of_irq_parse_and_map_pci(dev, 0, 0);
 
 	return 0;
 }
 
+#ifdef CONFIG_ACPI
+int pcibios_root_bridge_prepare(struct pci_host_bridge *bridge)
+{
+	struct pci_controller *sd = bridge->bus->sysdata;
+
+	ACPI_COMPANION_SET(&bridge->dev, sd->companion);
+	return 0;
+}
+
+void pcibios_add_bus(struct pci_bus *bus)
+{
+	acpi_pci_add_bus(bus);
+}
+
+void pcibios_remove_bus(struct pci_bus *bus)
+{
+	acpi_pci_remove_bus(bus);
+}
+
+int pcibios_enable_irq(struct pci_dev *dev)
+{
+	if (!pci_dev_msi_enabled(dev))
+		acpi_pci_irq_enable(dev);
+	return 0;
+}
+
+int pcibios_disable_irq(struct pci_dev *dev)
+{
+	if (!pci_dev_msi_enabled(dev))
+		acpi_pci_irq_disable(dev);
+	return 0;
+}
+
+int pcibios_enable_device(struct pci_dev *dev, int bars)
+{
+	int err;
+
+	err = pci_enable_resources(dev, bars);
+	if (err < 0)
+		return err;
+
+	return pcibios_enable_irq(dev);
+}
+
+static int __init pcibios_assign_resources(void)
+{
+	struct pci_bus *root_bus;
+
+	if (acpi_disabled)
+		return 0;
+
+	list_for_each_entry(root_bus, &pci_root_buses, node) {
+		pcibios_resource_survey_bus(root_bus);
+		pci_assign_unassigned_root_bus_resources(root_bus);
+	}
+	return 0;
+}
 /*
- * raw_pci_read/write - Platform-specific PCI config space access.
+ * fs_initcall comes after subsys_initcall, so we know acpi scan
+ * has run.
  */
-int raw_pci_read(unsigned int domain, unsigned int bus,
-		  unsigned int devfn, int reg, int len, u32 *val)
+fs_initcall(pcibios_assign_resources);
+
+static int pci_read(struct pci_bus *bus, unsigned int devfn, int where,
+		    int size, u32 *value)
 {
-	return -ENXIO;
+	return raw_pci_read(pci_domain_nr(bus), bus->number,
+			    devfn, where, size, value);
 }
 
-int raw_pci_write(unsigned int domain, unsigned int bus,
-		unsigned int devfn, int reg, int len, u32 val)
+static int pci_write(struct pci_bus *bus, unsigned int devfn, int where,
+		     int size, u32 value)
 {
-	return -ENXIO;
+	return raw_pci_write(pci_domain_nr(bus), bus->number,
+			     devfn, where, size, value);
 }
 
-#ifdef CONFIG_ACPI
+struct pci_ops pci_root_ops = {
+	.read = pci_read,
+	.write = pci_write,
+};
+
+struct pci_root_info {
+	struct acpi_pci_root_info common;
+#ifdef  CONFIG_PCI_MMCONFIG
+	bool mcfg_added;
+	u8 start_bus;
+	u8 end_bus;
+#endif
+};
+
+#ifdef CONFIG_PCI_MMCONFIG
+static int pci_add_mmconfig_region(struct acpi_pci_root_info *ci)
+{
+	struct pci_mmcfg_region *cfg;
+	struct pci_root_info *info;
+	struct acpi_pci_root *root = ci->root;
+	int err, seg = ci->controller.segment;
+
+	info = container_of(ci, struct pci_root_info, common);
+	info->start_bus = (u8)root->secondary.start;
+	info->end_bus = (u8)root->secondary.end;
+	info->mcfg_added = false;
+
+	rcu_read_lock();
+	cfg = pci_mmconfig_lookup(seg, info->start_bus);
+	rcu_read_unlock();
+	if (cfg)
+		return 0;
+
+	cfg = pci_mmconfig_alloc(seg, info->start_bus, info->end_bus,
+				 root->mcfg_addr);
+	if (!cfg)
+		return -ENOMEM;
+
+	err = pci_mmconfig_inject(cfg);
+	if (!err)
+		info->mcfg_added = true;
+
+	return err;
+}
+
+static void pci_remove_mmconfig_region(struct acpi_pci_root_info *ci)
+{
+	struct pci_root_info *info;
+
+	info = container_of(ci, struct pci_root_info, common);
+	if (info->mcfg_added) {
+		pci_mmconfig_delete(ci->controller.segment, info->start_bus,
+				    info->end_bus);
+		info->mcfg_added = false;
+	}
+}
+#else
+static int pci_add_mmconfig_region(struct acpi_pci_root_info *ci)
+{
+	return 0;
+}
+
+static void pci_remove_mmconfig_region(struct acpi_pci_root_info *ci) { }
+#endif
+
+static int pci_acpi_root_init_info(struct acpi_pci_root_info *ci)
+{
+	return pci_add_mmconfig_region(ci);
+}
+
+static void pci_acpi_root_release_info(struct acpi_pci_root_info *ci)
+{
+	struct pci_root_info *info;
+
+	info = container_of(ci, struct pci_root_info, common);
+	pci_remove_mmconfig_region(ci);
+	kfree(info);
+}
+
+static int pci_acpi_root_prepare_resources(struct acpi_pci_root_info *ci,
+					   int status)
+{
+	struct resource_entry *entry, *tmp;
+
+	resource_list_for_each_entry_safe(entry, tmp, &ci->resources) {
+		struct resource *res = entry->res;
+
+		/*
+		 * Special handling for ARM IO range
+		 * TODO: need to move pci_register_io_range() function out
+		 * of drivers/of/address.c for both used by DT and ACPI
+		 */
+		if (res->flags & IORESOURCE_IO) {
+			unsigned long port;
+			int err;
+			resource_size_t length = res->end - res->start;
+
+			err = pci_register_io_range(res->start, length);
+			if (err) {
+				resource_list_destroy_entry(entry);
+				continue;
+			}
+
+			port = pci_address_to_pio(res->start);
+			if (port == (unsigned long)-1) {
+				resource_list_destroy_entry(entry);
+				continue;
+			}
+
+			res->start = port;
+			res->end = res->start + length - 1;
+
+			if (pci_remap_iospace(res, res->start) < 0)
+				resource_list_destroy_entry(entry);
+		}
+	}
+
+	return status;
+}
+
+static struct acpi_pci_root_ops acpi_pci_root_ops = {
+	.pci_ops = &pci_root_ops,
+	.init_info = pci_acpi_root_init_info,
+	.release_info = pci_acpi_root_release_info,
+	.prepare_resources = pci_acpi_root_prepare_resources,
+};
+
 /* Root bridge scanning */
 struct pci_bus *pci_acpi_scan_root(struct acpi_pci_root *root)
 {
-	/* TODO: Should be revisited when implementing PCI on ACPI */
-	return NULL;
+	struct pci_root_info *info;
+	int node;
+	int domain = root->segment;
+	int busnum = root->secondary.start;
+	struct pci_bus *bus;
+
+	if (domain && !pci_domains_supported) {
+		pr_warn("PCI %04x:%02x: multiple domains not supported.\n",
+			domain, busnum);
+		return NULL;
+	}
+
+	node = acpi_get_node(root->device->handle);
+	info = kzalloc_node(sizeof(*info), GFP_KERNEL, node);
+	if (!info) {
+		dev_err(&root->device->dev, "pci_bus %04x:%02x: ignored (out of memory)\n",
+			domain, busnum);
+		return NULL;
+	}
+
+	bus = acpi_pci_root_create(root, &acpi_pci_root_ops, &info->common);
+
+	/* After the PCI-E bus has been walked and all devices discovered,
+	 * configure any settings of the fabric that might be necessary.
+	 */
+	if (bus) {
+		struct pci_bus *child;
+
+		list_for_each_entry(child, &bus->children, node)
+			pcie_bus_configure_settings(child);
+	}
+
+	return bus;
 }
 #endif
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index acc4b6e..0268a1d 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -25,6 +25,7 @@
 #include <linux/device.h>
 #include <linux/pm_runtime.h>
 #include <linux/pci_hotplug.h>
+#include <linux/acpi.h>
 #include <asm-generic/pci-bridge.h>
 #include <asm/setup.h>
 #include "pci.h"
@@ -4509,7 +4510,7 @@ int pci_get_new_domain_nr(void)
 void pci_bus_assign_domain_nr(struct pci_bus *bus, struct device *parent)
 {
 	static int use_dt_domains = -1;
-	int domain = of_get_pci_domain_nr(parent->of_node);
+	int domain;
 
 	/*
 	 * Check DT domain and use_dt_domains values.
@@ -4537,17 +4538,22 @@ void pci_bus_assign_domain_nr(struct pci_bus *bus, struct device *parent)
 	 * invalidating the domain value (domain = -1) and printing a
 	 * corresponding error.
 	 */
-	if (domain >= 0 && use_dt_domains) {
-		use_dt_domains = 1;
-	} else if (domain < 0 && use_dt_domains != 1) {
-		use_dt_domains = 0;
-		domain = pci_get_new_domain_nr();
+	if (acpi_disabled) {
+		domain = of_get_pci_domain_nr(parent->of_node);
+		if (domain >= 0 && use_dt_domains) {
+			use_dt_domains = 1;
+		} else if (domain < 0 && use_dt_domains != 1) {
+			use_dt_domains = 0;
+			domain = pci_get_new_domain_nr();
+		} else {
+			dev_err(parent, "Node %s has inconsistent \"linux,pci-domain\" property in DT\n",
+				parent->of_node->full_name);
+			domain = -1;
+		}
 	} else {
-		dev_err(parent, "Node %s has inconsistent \"linux,pci-domain\" property in DT\n",
-			parent->of_node->full_name);
-		domain = -1;
+		struct pci_controller *sd = bus->sysdata;
+		domain = sd->segment;
 	}
-
 	bus->domain_nr = domain;
 }
 #endif
