/*-
 * Written by paradox <ddkprog@yahoo.com>
 * Public domain.
 */

#include <sys/cdefs.h>
__FBSDID("$FreeBSD: head/sys/dev/x86bios/x86bios.c 197387 2009-09-21 08:53:26Z delphij $");

#include "opt_x86bios.h"

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/module.h>
#include <sys/lock.h>
#include <sys/mutex.h>

#include <vm/vm.h>
#include <vm/vm_extern.h>
#include <vm/vm_kern.h>
#include <vm/vm_param.h>
#include <vm/pmap.h>

#include <machine/cpufunc.h>

#include <contrib/x86emu/x86emu.h>
#include <contrib/x86emu/x86emu_regs.h>
#include <dev/x86bios/x86bios.h>

u_char *pbiosMem = NULL;
static u_char *pbiosStack = NULL;

int busySegMap[5];

static struct x86emu xbios86emu;

static struct mtx x86bios_lock;

static uint8_t
vm86_emu_inb(struct x86emu *emu, uint16_t port)
{
	if (port == 0xb2) /* APM scratch register */
		return 0;
	if (port >= 0x80 && port < 0x88) /* POST status register */
		return 0;
	return inb(port);
}

static uint16_t
vm86_emu_inw(struct x86emu *emu, uint16_t port)
{
	if (port >= 0x80 && port < 0x88) /* POST status register */
		return 0;
	return inw(port);
}

static uint32_t
vm86_emu_inl(struct x86emu *emu, uint16_t port)
{
	if (port >= 0x80 && port < 0x88) /* POST status register */
		return 0;
	return inl(port);
}

static void
vm86_emu_outb(struct x86emu *emu, uint16_t port, uint8_t val)
{
	if (port == 0xb2) /* APM scratch register */
		return;
	if (port >= 0x80 && port < 0x88) /* POST status register */
		return;
	outb(port, val);
}

static void
vm86_emu_outw(struct x86emu *emu, uint16_t port, uint16_t val)
{
	if (port >= 0x80 && port < 0x88) /* POST status register */
		return;
	outw(port, val);
}

static void
vm86_emu_outl(struct x86emu *emu, uint16_t port, uint32_t val)
{
	if (port >= 0x80 && port < 0x88) /* POST status register */
		return;
	outl(port, val);
}

void
x86biosCall(struct x86regs *regs, int intno)
{
	if (intno < 0 || intno > 255)
		return;

	mtx_lock(&x86bios_lock);
	critical_enter();

	xbios86emu.x86.R_EAX = regs->R_EAX;
	xbios86emu.x86.R_EBX = regs->R_EBX;
	xbios86emu.x86.R_ECX = regs->R_ECX;
	xbios86emu.x86.R_EDX = regs->R_EDX;

	xbios86emu.x86.R_ESP = regs->R_ESP;
	xbios86emu.x86.R_EBP = regs->R_EBP;
	xbios86emu.x86.R_ESI = regs->R_ESI;
	xbios86emu.x86.R_EDI = regs->R_EDI;
	xbios86emu.x86.R_EIP = regs->R_EIP;
	xbios86emu.x86.R_EFLG = regs->R_EFLG;

	xbios86emu.x86.R_CS = regs->R_CS;
	xbios86emu.x86.R_DS = regs->R_DS;
	xbios86emu.x86.R_SS = regs->R_SS;
	xbios86emu.x86.R_ES = regs->R_ES;
	xbios86emu.x86.R_FS = regs->R_FS;
	xbios86emu.x86.R_GS = regs->R_GS;

	x86emu_exec_intr(&xbios86emu, intno);

	regs->R_EAX = xbios86emu.x86.R_EAX;
	regs->R_EBX = xbios86emu.x86.R_EBX;
	regs->R_ECX = xbios86emu.x86.R_ECX;
	regs->R_EDX = xbios86emu.x86.R_EDX;

	regs->R_ESP = xbios86emu.x86.R_ESP;
	regs->R_EBP = xbios86emu.x86.R_EBP;
	regs->R_ESI = xbios86emu.x86.R_ESI;
	regs->R_EDI = xbios86emu.x86.R_EDI;
	regs->R_EIP = xbios86emu.x86.R_EIP;
	regs->R_EFLG = xbios86emu.x86.R_EFLG;

	regs->R_CS = xbios86emu.x86.R_CS;
	regs->R_DS = xbios86emu.x86.R_DS;
	regs->R_SS = xbios86emu.x86.R_SS;
	regs->R_ES = xbios86emu.x86.R_ES;
	regs->R_FS = xbios86emu.x86.R_FS;
	regs->R_GS = xbios86emu.x86.R_GS;

	critical_exit();
	mtx_unlock(&x86bios_lock);
}

void *
x86biosOffs(uint32_t offs)
{
	return (pbiosMem + offs);
}

static void
x86bios_init(void *arg __unused)
{
	int offs;

	mtx_init(&x86bios_lock, "x86bios lock", NULL, MTX_DEF);

	/* Can pbiosMem be NULL here? */
	pbiosMem = pmap_mapbios(0x0, MAPPED_MEMORY_SIZE);

	memset(&xbios86emu, 0, sizeof(xbios86emu));
	x86emu_init_default(&xbios86emu);

	xbios86emu.emu_inb = vm86_emu_inb;
	xbios86emu.emu_inw = vm86_emu_inw;
	xbios86emu.emu_inl = vm86_emu_inl;
	xbios86emu.emu_outb = vm86_emu_outb;
	xbios86emu.emu_outw = vm86_emu_outw;
	xbios86emu.emu_outl = vm86_emu_outl;

	xbios86emu.mem_base = (char *)pbiosMem;
	xbios86emu.mem_size = 1024 * 1024;

	memset(busySegMap, 0, sizeof(busySegMap));

	pbiosStack = x86biosAlloc(1, &offs);
}

static void
x86bios_uninit(void *arg __unused)
{
	x86biosFree(pbiosStack, 1);

	if (pbiosMem)
		pmap_unmapdev((vm_offset_t)pbiosMem,
		    MAPPED_MEMORY_SIZE);

	mtx_destroy(&x86bios_lock);
}

static int
x86bios_modevent(module_t mod __unused, int type, void *data __unused)
{
	int err = 0;

	switch (type) {
	case MOD_LOAD:
		x86bios_init(NULL);
		break;
	case MOD_UNLOAD:
		x86bios_uninit(NULL);
		break;
	default:
		err = ENOTSUP;
		break;
	}

	return (err);
}

static moduledata_t x86bios_mod = {
	"x86bios",
	x86bios_modevent,
	NULL,
};

DECLARE_MODULE(x86bios, x86bios_mod, SI_SUB_KLD, SI_ORDER_ANY);
MODULE_VERSION(x86bios, 1);