arch/sh/kernel/sh_bios.c

/*
 *  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/module.h>
#include <asm/sh_bios.h>

#define BIOS_CALL_CONSOLE_WRITE		0
#define BIOS_CALL_ETH_NODE_ADDR		10
#define BIOS_CALL_SHUTDOWN		11
#define BIOS_CALL_CHAR_OUT		0x1f	/* TODO: hack */
#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);
}

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

void sh_bios_get_node_addr(unsigned char *node_addr)
{
	sh_bios_call(BIOS_CALL_ETH_NODE_ADDR, 0, (long)node_addr, 0, 0);
}
EXPORT_SYMBOL_GPL(sh_bios_get_node_addr);

void sh_bios_shutdown(unsigned int how)
{
	sh_bios_call(BIOS_CALL_SHUTDOWN, how, 0, 0, 0);
}

void *gdb_vbr_vector = NULL;

/*
 * Read the old value of the VBR register to initialise the vector
 * through which debug and BIOS traps are delegated by the Linux trap
 * handler.
 */
void sh_bios_vbr_init(void)
{
	unsigned long vbr;

	if (unlikely(gdb_vbr_vector))
		return;

	__asm__ __volatile__ ("stc vbr, %0" : "=r" (vbr));

	gdb_vbr_vector = (void *)(vbr + 0x100);
	printk(KERN_NOTICE "Setting GDB trap vector to %p\n", gdb_vbr_vector);
}

/**
 * sh_bios_vbr_reload - Re-load the system VBR from the BIOS vector.
 *
 * This can be used by save/restore code to reinitialize the system VBR
 * from the fixed BIOS VBR. A no-op if no BIOS VBR is known.
 */
void sh_bios_vbr_reload(void)
{
	if (gdb_vbr_vector)
		__asm__ __volatile__ (
			"ldc %0, vbr"
			:
			: "r" (((unsigned long) gdb_vbr_vector) - 0x100)
			: "memory"
		);
}