v4.19.13 snapshot.
diff --git a/arch/x86/kernel/devicetree.c b/arch/x86/kernel/devicetree.c
new file mode 100644
index 0000000..f39f3a0
--- /dev/null
+++ b/arch/x86/kernel/devicetree.c
@@ -0,0 +1,323 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Architecture specific OF callbacks.
+ */
+#include <linux/export.h>
+#include <linux/io.h>
+#include <linux/interrupt.h>
+#include <linux/list.h>
+#include <linux/of.h>
+#include <linux/of_fdt.h>
+#include <linux/of_address.h>
+#include <linux/of_platform.h>
+#include <linux/of_irq.h>
+#include <linux/libfdt.h>
+#include <linux/slab.h>
+#include <linux/pci.h>
+#include <linux/of_pci.h>
+#include <linux/initrd.h>
+
+#include <asm/irqdomain.h>
+#include <asm/hpet.h>
+#include <asm/apic.h>
+#include <asm/pci_x86.h>
+#include <asm/setup.h>
+#include <asm/i8259.h>
+
+__initdata u64 initial_dtb;
+char __initdata cmd_line[COMMAND_LINE_SIZE];
+
+int __initdata of_ioapic;
+
+void __init early_init_dt_scan_chosen_arch(unsigned long node)
+{
+	BUG();
+}
+
+void __init early_init_dt_add_memory_arch(u64 base, u64 size)
+{
+	BUG();
+}
+
+void __init add_dtb(u64 data)
+{
+	initial_dtb = data + offsetof(struct setup_data, data);
+}
+
+/*
+ * CE4100 ids. Will be moved to machine_device_initcall() once we have it.
+ */
+static struct of_device_id __initdata ce4100_ids[] = {
+	{ .compatible = "intel,ce4100-cp", },
+	{ .compatible = "isa", },
+	{ .compatible = "pci", },
+	{},
+};
+
+static int __init add_bus_probe(void)
+{
+	if (!of_have_populated_dt())
+		return 0;
+
+	return of_platform_bus_probe(NULL, ce4100_ids, NULL);
+}
+device_initcall(add_bus_probe);
+
+#ifdef CONFIG_PCI
+struct device_node *pcibios_get_phb_of_node(struct pci_bus *bus)
+{
+	struct device_node *np;
+
+	for_each_node_by_type(np, "pci") {
+		const void *prop;
+		unsigned int bus_min;
+
+		prop = of_get_property(np, "bus-range", NULL);
+		if (!prop)
+			continue;
+		bus_min = be32_to_cpup(prop);
+		if (bus->number == bus_min)
+			return np;
+	}
+	return NULL;
+}
+
+static int x86_of_pci_irq_enable(struct pci_dev *dev)
+{
+	u32 virq;
+	int ret;
+	u8 pin;
+
+	ret = pci_read_config_byte(dev, PCI_INTERRUPT_PIN, &pin);
+	if (ret)
+		return ret;
+	if (!pin)
+		return 0;
+
+	virq = of_irq_parse_and_map_pci(dev, 0, 0);
+	if (virq == 0)
+		return -EINVAL;
+	dev->irq = virq;
+	return 0;
+}
+
+static void x86_of_pci_irq_disable(struct pci_dev *dev)
+{
+}
+
+void x86_of_pci_init(void)
+{
+	pcibios_enable_irq = x86_of_pci_irq_enable;
+	pcibios_disable_irq = x86_of_pci_irq_disable;
+}
+#endif
+
+static void __init dtb_setup_hpet(void)
+{
+#ifdef CONFIG_HPET_TIMER
+	struct device_node *dn;
+	struct resource r;
+	int ret;
+
+	dn = of_find_compatible_node(NULL, NULL, "intel,ce4100-hpet");
+	if (!dn)
+		return;
+	ret = of_address_to_resource(dn, 0, &r);
+	if (ret) {
+		WARN_ON(1);
+		return;
+	}
+	hpet_address = r.start;
+#endif
+}
+
+#ifdef CONFIG_X86_LOCAL_APIC
+
+static void __init dtb_cpu_setup(void)
+{
+	struct device_node *dn;
+	u32 apic_id, version;
+	int ret;
+
+	version = GET_APIC_VERSION(apic_read(APIC_LVR));
+	for_each_node_by_type(dn, "cpu") {
+		ret = of_property_read_u32(dn, "reg", &apic_id);
+		if (ret < 0) {
+			pr_warn("%pOF: missing local APIC ID\n", dn);
+			continue;
+		}
+		generic_processor_info(apic_id, version);
+	}
+}
+
+static void __init dtb_lapic_setup(void)
+{
+	struct device_node *dn;
+	struct resource r;
+	unsigned long lapic_addr = APIC_DEFAULT_PHYS_BASE;
+	int ret;
+
+	dn = of_find_compatible_node(NULL, NULL, "intel,ce4100-lapic");
+	if (dn) {
+		ret = of_address_to_resource(dn, 0, &r);
+		if (WARN_ON(ret))
+			return;
+		lapic_addr = r.start;
+	}
+
+	/* Did the boot loader setup the local APIC ? */
+	if (!boot_cpu_has(X86_FEATURE_APIC)) {
+		if (apic_force_enable(lapic_addr))
+			return;
+	}
+	smp_found_config = 1;
+	pic_mode = 1;
+	register_lapic_address(lapic_addr);
+}
+
+#endif /* CONFIG_X86_LOCAL_APIC */
+
+#ifdef CONFIG_X86_IO_APIC
+static unsigned int ioapic_id;
+
+struct of_ioapic_type {
+	u32 out_type;
+	u32 trigger;
+	u32 polarity;
+};
+
+static struct of_ioapic_type of_ioapic_type[] =
+{
+	{
+		.out_type	= IRQ_TYPE_EDGE_RISING,
+		.trigger	= IOAPIC_EDGE,
+		.polarity	= 1,
+	},
+	{
+		.out_type	= IRQ_TYPE_LEVEL_LOW,
+		.trigger	= IOAPIC_LEVEL,
+		.polarity	= 0,
+	},
+	{
+		.out_type	= IRQ_TYPE_LEVEL_HIGH,
+		.trigger	= IOAPIC_LEVEL,
+		.polarity	= 1,
+	},
+	{
+		.out_type	= IRQ_TYPE_EDGE_FALLING,
+		.trigger	= IOAPIC_EDGE,
+		.polarity	= 0,
+	},
+};
+
+static int dt_irqdomain_alloc(struct irq_domain *domain, unsigned int virq,
+			      unsigned int nr_irqs, void *arg)
+{
+	struct irq_fwspec *fwspec = (struct irq_fwspec *)arg;
+	struct of_ioapic_type *it;
+	struct irq_alloc_info tmp;
+	int type_index;
+
+	if (WARN_ON(fwspec->param_count < 2))
+		return -EINVAL;
+
+	type_index = fwspec->param[1];
+	if (type_index >= ARRAY_SIZE(of_ioapic_type))
+		return -EINVAL;
+
+	it = &of_ioapic_type[type_index];
+	ioapic_set_alloc_attr(&tmp, NUMA_NO_NODE, it->trigger, it->polarity);
+	tmp.ioapic_id = mpc_ioapic_id(mp_irqdomain_ioapic_idx(domain));
+	tmp.ioapic_pin = fwspec->param[0];
+
+	return mp_irqdomain_alloc(domain, virq, nr_irqs, &tmp);
+}
+
+static const struct irq_domain_ops ioapic_irq_domain_ops = {
+	.alloc		= dt_irqdomain_alloc,
+	.free		= mp_irqdomain_free,
+	.activate	= mp_irqdomain_activate,
+	.deactivate	= mp_irqdomain_deactivate,
+};
+
+static void __init dtb_add_ioapic(struct device_node *dn)
+{
+	struct resource r;
+	int ret;
+	struct ioapic_domain_cfg cfg = {
+		.type = IOAPIC_DOMAIN_DYNAMIC,
+		.ops = &ioapic_irq_domain_ops,
+		.dev = dn,
+	};
+
+	ret = of_address_to_resource(dn, 0, &r);
+	if (ret) {
+		printk(KERN_ERR "Can't obtain address from device node %pOF.\n", dn);
+		return;
+	}
+	mp_register_ioapic(++ioapic_id, r.start, gsi_top, &cfg);
+}
+
+static void __init dtb_ioapic_setup(void)
+{
+	struct device_node *dn;
+
+	for_each_compatible_node(dn, NULL, "intel,ce4100-ioapic")
+		dtb_add_ioapic(dn);
+
+	if (nr_ioapics) {
+		of_ioapic = 1;
+		return;
+	}
+	printk(KERN_ERR "Error: No information about IO-APIC in OF.\n");
+}
+#else
+static void __init dtb_ioapic_setup(void) {}
+#endif
+
+static void __init dtb_apic_setup(void)
+{
+#ifdef CONFIG_X86_LOCAL_APIC
+	dtb_lapic_setup();
+	dtb_cpu_setup();
+#endif
+	dtb_ioapic_setup();
+}
+
+#ifdef CONFIG_OF_EARLY_FLATTREE
+static void __init x86_flattree_get_config(void)
+{
+	u32 size, map_len;
+	void *dt;
+
+	if (!initial_dtb)
+		return;
+
+	map_len = max(PAGE_SIZE - (initial_dtb & ~PAGE_MASK), (u64)128);
+
+	dt = early_memremap(initial_dtb, map_len);
+	size = fdt_totalsize(dt);
+	if (map_len < size) {
+		early_memunmap(dt, map_len);
+		dt = early_memremap(initial_dtb, size);
+		map_len = size;
+	}
+
+	early_init_dt_verify(dt);
+	unflatten_and_copy_device_tree();
+	early_memunmap(dt, map_len);
+}
+#else
+static inline void x86_flattree_get_config(void) { }
+#endif
+
+void __init x86_dtb_init(void)
+{
+	x86_flattree_get_config();
+
+	if (!of_have_populated_dt())
+		return;
+
+	dtb_setup_hpet();
+	dtb_apic_setup();
+}