/* SPDX-License-Identifier: GPL-2.0-only */

#include <assert.h>
#include <cpu/cpu.h>
#include <cpu/x86/lapic.h>
#include <cpu/x86/lapic_def.h>
#include <cpu/x86/msr.h>
#include <console/console.h>
#include <smp/node.h>
#include <stdint.h>

void enable_lapic(void)
{
	uintptr_t apic_base;
	bool use_x2apic;
	msr_t msr;

	msr = rdmsr(LAPIC_BASE_MSR);
	if (!(msr.lo & LAPIC_BASE_MSR_ENABLE)) {
		msr.hi &= 0xffffff00;
		msr.lo &= ~LAPIC_BASE_MSR_ADDR_MASK;
		msr.lo |= LAPIC_DEFAULT_BASE;
		msr.lo |= LAPIC_BASE_MSR_ENABLE;
		wrmsr(LAPIC_BASE_MSR, msr);
		msr = rdmsr(LAPIC_BASE_MSR);
	}

	ASSERT(msr.lo & LAPIC_BASE_MSR_ENABLE);

	apic_base = msr.lo & LAPIC_BASE_MSR_ADDR_MASK;
	ASSERT(apic_base == LAPIC_DEFAULT_BASE);

	if (CONFIG(XAPIC_ONLY)) {
		use_x2apic = false;
	} else {
		use_x2apic = !!(cpu_get_feature_flags_ecx() & CPUID_X2APIC);
		ASSERT(CONFIG(X2APIC_RUNTIME) || use_x2apic);
	}

	if (use_x2apic == !!(msr.lo & LAPIC_BASE_MSR_X2APIC_MODE)) {
		printk(BIOS_INFO, "LAPIC 0x%x in %s mode.\n", lapicid(),
				  use_x2apic ? "X2APIC" : "XAPIC");
	} else if (use_x2apic) {
		msr.lo |= LAPIC_BASE_MSR_X2APIC_MODE;
		wrmsr(LAPIC_BASE_MSR, msr);
		msr = rdmsr(LAPIC_BASE_MSR);
		ASSERT(!!(msr.lo & LAPIC_BASE_MSR_X2APIC_MODE));
		printk(BIOS_INFO, "LAPIC 0x%x switched to X2APIC mode.\n", lapicid());
	} else {
		die("Switching from X2APIC to XAPIC mode is not implemented.");
	}

}

void disable_lapic(void)
{
	msr_t msr;
	msr = rdmsr(LAPIC_BASE_MSR);
	msr.lo &= ~(LAPIC_BASE_MSR_ENABLE | LAPIC_BASE_MSR_X2APIC_MODE);
	wrmsr(LAPIC_BASE_MSR, msr);
}

uintptr_t cpu_get_lapic_addr(void)
{
	return LAPIC_DEFAULT_BASE;
}

/* See if I need to initialize the local APIC */
static int need_lapic_init(void)
{
	return CONFIG(SMP) || CONFIG(IOAPIC);
}

static void lapic_virtual_wire_mode_init(void)
{
	/*
	 * Set Task Priority to 'accept all'.
	 */
	lapic_update32(LAPIC_TASKPRI, ~LAPIC_TPRI_MASK, 0);

	/* Set spurious interrupt vector to 0 and keep LAPIC enabled to
	   be able to clear LVT register mask bits. */
	lapic_update32(LAPIC_SPIV, ~LAPIC_VECTOR_MASK, LAPIC_SPIV_ENABLE);

	/* Put the local APIC in virtual wire mode */
	uint32_t mask = LAPIC_LVT_MASKED | LAPIC_LVT_LEVEL_TRIGGER | LAPIC_INPUT_POLARITY |
			LAPIC_DELIVERY_MODE_MASK;

	if (boot_cpu())
		lapic_update32(LAPIC_LVT0, ~mask, LAPIC_DELIVERY_MODE_EXTINT);
	else
		lapic_update32(LAPIC_LVT0, ~mask, LAPIC_LVT_MASKED |
						  LAPIC_DELIVERY_MODE_EXTINT);

	lapic_update32(LAPIC_LVT1, ~mask, LAPIC_DELIVERY_MODE_NMI);
}

void setup_lapic(void)
{
	/* Enable the local APIC */
	if (need_lapic_init())
		enable_lapic();
	else if (!CONFIG(UDELAY_LAPIC))
		disable_lapic();

	/* This programming is for PIC mode i8259 interrupts to be delivered to CPU
	   while LAPIC is enabled. */
	if (need_lapic_init())
		lapic_virtual_wire_mode_init();
}