diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 07d1811..bbcc6b1 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -89,6 +89,7 @@ config ARM64
 	select SPARSE_IRQ
 	select SYSCTL_EXCEPTION_TRACE
 	select HAVE_CONTEXT_TRACKING
+	select HAVE_PCI_ECAM
 	help
 	  ARM 64-bit (AArch64) Linux support.
 
@@ -202,6 +203,11 @@ source "drivers/pci/Kconfig"
 source "drivers/pci/pcie/Kconfig"
 source "drivers/pci/hotplug/Kconfig"
 
+config PCI_MMCONFIG
+	def_bool y
+	select PCI_ECAM
+	depends on ACPI
+
 endmenu
 
 menu "Kernel Features"
diff --git a/arch/arm64/kernel/pci.c b/arch/arm64/kernel/pci.c
index b3d098b..66cc1ae 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>
@@ -52,35 +55,216 @@ int pcibios_enable_device(struct pci_dev *dev, int mask)
 }
 
 /*
- * Try to assign the IRQ number from DT when adding a new device
+ * Try to assign the IRQ number from DT/ACPI when adding a new device
  */
 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);
+#ifdef CONFIG_ACPI
+	else
+		acpi_pci_irq_enable(dev);
+#endif
 
 	return 0;
 }
 
+#ifdef CONFIG_ACPI
+int pcibios_root_bridge_prepare(struct pci_host_bridge *bridge)
+{
+	struct acpi_pci_root *root = bridge->bus->sysdata;
+
+	ACPI_COMPANION_SET(&bridge->dev, root->device);
+	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);
+}
+
+static int __init pcibios_assign_resources(void)
+{
+	if (acpi_disabled)
+		return 0;
+
+	pci_assign_unassigned_resources();
+	return 0;
+}
 /*
- * raw_pci_read/write - Platform-specific PCI config space access.
+ * rootfs_initcall comes after subsys_initcall and fs_initcall_sync,
+ * so we know acpi scan and PCI_FIXUP_FINAL quirks have both run.
  */
-int raw_pci_read(unsigned int domain, unsigned int bus,
-		  unsigned int devfn, int reg, int len, u32 *val)
+rootfs_initcall(pcibios_assign_resources);
+
+static void __iomem *
+pci_mcfg_dev_base(struct pci_bus *bus, unsigned int devfn, int offset)
 {
-	return -ENXIO;
+	struct pci_mmcfg_region *cfg;
+
+	cfg = pci_mmconfig_lookup(pci_domain_nr(bus), bus->number);
+	if (cfg && cfg->virt)
+		return cfg->virt +
+			(PCI_MMCFG_BUS_OFFSET(bus->number) | (devfn << 12)) +
+			offset;
+	return NULL;
 }
 
-int raw_pci_write(unsigned int domain, unsigned int bus,
-		unsigned int devfn, int reg, int len, u32 val)
+struct pci_ops pci_root_ops = {
+	.map_bus = pci_mcfg_dev_base,
+	.read = pci_generic_config_read,
+	.write = pci_generic_config_write,
+};
+
+#ifdef CONFIG_PCI_MMCONFIG
+static int pci_add_mmconfig_region(struct acpi_pci_root_info *ci)
 {
-	return -ENXIO;
+	struct pci_mmcfg_region *cfg;
+	struct acpi_pci_root *root;
+	int seg, start, end, err;
+
+	root = ci->root;
+	seg = root->segment;
+	start = root->secondary.start;
+	end = root->secondary.end;
+
+	cfg = pci_mmconfig_lookup(seg, start);
+	if (cfg)
+		return 0;
+
+	cfg = pci_mmconfig_alloc(seg, start, end, root->mcfg_addr);
+	if (!cfg)
+		return -ENOMEM;
+
+	err = pci_mmconfig_inject(cfg);
+	return err;
 }
 
-#ifdef CONFIG_ACPI
+static void pci_remove_mmconfig_region(struct acpi_pci_root_info *ci)
+{
+	struct acpi_pci_root *root = ci->root;
+	struct pci_mmcfg_region *cfg;
+
+	cfg = pci_mmconfig_lookup(root->segment, root->secondary.start);
+	if (cfg)
+		return;
+
+	if (cfg->hot_added)
+		pci_mmconfig_delete(root->segment, root->secondary.start,
+				    root->secondary.end);
+}
+#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)
+{
+	pci_remove_mmconfig_region(ci);
+	kfree(ci);
+}
+
+static int pci_acpi_root_prepare_resources(struct acpi_pci_root_info *ci)
+{
+	struct resource_entry *entry, *tmp;
+	int ret;
+
+	ret = acpi_pci_probe_root_resources(ci);
+	if (ret < 0)
+		return ret;
+
+	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 0;
+}
+
+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;
+	int node = acpi_get_node(root->device->handle);
+	int domain = root->segment;
+	int busnum = root->secondary.start;
+	struct acpi_pci_root_info *info;
+	struct pci_bus *bus;
+
+	if (domain && !pci_domains_supported) {
+		pr_warn("PCI %04x:%02x: multiple domains not supported.\n",
+			domain, busnum);
+		return NULL;
+	}
+
+	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, root);
+
+	/* 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
