/* $Id: sh_bios.c,v 1.2 2000/07/26 04:37:32 gniibe Exp $
 *
 *  linux/arch/sh/kernel/sh_bios.c
 *  C interface for trapping into the standard LinuxSH BIOS.
 *
 *  Copyright (C) 2000 Greg Banks, Mitch Davis
 *
 */

#include <linux/config.h>
#include <asm/sh_bios.h>

#ifdef CONFIG_SH_STANDARD_BIOS

#define BIOS_CALL_CONSOLE_WRITE     	0
#define BIOS_CALL_READ_BLOCK     	1   	/* not implemented */
#define BIOS_CALL_CHAR_OUT     	    	0x1f  	/* TODO: hack */
#define BIOS_CALL_GDB_GET_MODE_PTR     	0xfe
#define BIOS_CALL_GDB_DETACH     	0xff

static __inline__ long sh_bios_call(long func, long arg0, long arg1, long arg2, long arg3)
{
    register long r0 __asm__("$r0") = func;
    register long r4 __asm__("$r4") = arg0;
    register long r5 __asm__("$r5") = arg1;
    register long r6 __asm__("$r6") = arg2;
    register long r7 __asm__("$r7") = arg3;
    __asm__ __volatile__("trapa	#0x3f"
	 : "=z" (r0)
	 : "0" (r0), "r" (r4), "r" (r5), "r" (r6), "r" (r7)
	 : "memory");
    return r0;
}


void sh_bios_console_write(const char *buf, unsigned int len)
{
    sh_bios_call(BIOS_CALL_CONSOLE_WRITE, (long)buf, (long)len, 0, 0);
}


void sh_bios_char_out(char ch)
{
    sh_bios_call(BIOS_CALL_CHAR_OUT, ch, 0, 0, 0);
}


int sh_bios_in_gdb_mode(void)
{
    static char queried = 0;
    static char *gdb_mode_p = 0;

    if (!queried)
    {
    	/* Query the gdb stub for address of its gdb mode variable */
    	long r = sh_bios_call(BIOS_CALL_GDB_GET_MODE_PTR, 0, 0, 0, 0);
	if (r != ~0)	/* BIOS returns -1 for unknown function */
	    gdb_mode_p = (char *)r;
	queried = 1;
    }
    return (gdb_mode_p != 0 ? *gdb_mode_p : 0);
}

void sh_bios_gdb_detach(void)
{
    sh_bios_call(BIOS_CALL_GDB_DETACH, 0, 0, 0, 0);
}

#endif