#include <stdbool.h>
#include "bios.h"
#include "stdio.h"
#include "e820.h"
#include "string.h"
#include "segment.h"
#include "fw_cfg.h"
#include "pflash.h"

static void set_realmode_int(int vec, void *p)
{
	uint16_t *realmode_idt = (uint16_t *) 0;
	realmode_idt[vec * 2] = flat_to_off16((uintptr_t) p);
	realmode_idt[vec * 2 + 1] = flat_to_seg16((uintptr_t) p);
}

static void setup_idt(void)
{
	int i;
	for (i = 0; i < 0x1f; i++)
		set_realmode_int(i, bios_intfake);
	for (i = 8; i < 16; i++)
		set_realmode_int(i, bios_irq);
	for (i = 0x70; i < 0x78; i++)
		set_realmode_int(i, bios_irq);
	set_realmode_int(0x10, bios_int10);
	set_realmode_int(0x15, bios_int15);
}

/* Top of memory below 4GB.  */
uint32_t lowmem;
struct e820map *e820;

static void extract_e820(void)
{
	int id = fw_cfg_file_id("etc/e820");
	uint32_t size;
	int nr_map;
	int i;

	if (id == -1)
		panic();

	size = fw_cfg_file_size(id);
	nr_map = size / sizeof(e820->map[0]) + 4;

	e820 = malloc(offsetof(struct e820map, map[nr_map]));
	e820->nr_map = nr_map;
	e820->map[0] = (struct e820entry)
		{ .addr = 0, .size = 639 * 1024, .type = E820_RAM }; /* low RAM */
	e820->map[1] = (struct e820entry)
		{ .addr = 639 * 1024, .size = 1024, .type = E820_RESERVED }; /* EBDA */
	e820->map[2] = (struct e820entry)
		{ .addr = 0xd0000, .size = 128 * 1024, .type = E820_NVS }; /* ACPI tables */
	e820->map[3] = (struct e820entry)
		{ .addr = 0xf0000, .size = 64 * 1024, .type = E820_RESERVED }; /* firmware */
	fw_cfg_read_file(id, &e820->map[4], size);
	for (i = 4; i < e820->nr_map; i++)
		if (e820->map[i].addr == 0) {
			lowmem = e820->map[i].size;
			e820->map[i].addr = 1024 * 1024;
			e820->map[i].size -= 1024 * 1024;
			break;
		}

	e820_seg = ((uintptr_t) e820) >> 4;
}

static bool detect_cbfs_and_boot(void)
{
	size_t sz;
	void *base = pflash_base(1, &sz);

	if (!base)
		return false;

	return boot_from_cbfs(base, sz);
}

int __attribute__ ((section (".text.startup"))) main(void)
{
	setup_hw();

	// Now go to the F-segment: we need to move away from flash area
	// in order to probe CBFS!
	asm("ljmp $0x8, $1f; 1:");

	setup_pci();
	setup_idt();
	fw_cfg_setup();
	extract_acpi();
	extract_e820();
	// extract_smbios();
	if (!detect_cbfs_and_boot())
		boot_from_fwcfg();
	panic();
}