arch/sh/kernel/sh_bios.c

Source file repositories/reference/linux-study-clean/arch/sh/kernel/sh_bios.c

File Facts

System
Linux kernel
Corpus path
arch/sh/kernel/sh_bios.c
Extension
.c
Size
3877 bytes
Lines
170
Domain
Architecture Layer
Bucket
arch/sh
Inferred role
Architecture Layer: exported/initcall integration point
Status
integration implementation candidate

Why This File Exists

CPU and platform-specific kernel glue: boot entry, traps, syscall entry, interrupts, page tables, context switch, and low-level barriers.

Dependency Surface

Detected Declarations

Annotated Snippet

// SPDX-License-Identifier: GPL-2.0
/*
 *  C interface for trapping into the standard LinuxSH BIOS.
 *
 *  Copyright (C) 2000 Greg Banks, Mitch Davis
 *  Copyright (C) 1999, 2000  Niibe Yutaka
 *  Copyright (C) 2002  M. R. Brown
 *  Copyright (C) 2004 - 2010  Paul Mundt
 */
#include <linux/module.h>
#include <linux/console.h>
#include <linux/tty.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/delay.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_GDB_DETACH		0xff

void *gdb_vbr_vector = NULL;

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;

	if (!gdb_vbr_vector)
		return -ENOSYS;

	__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_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);
}

/*
 * 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));

	if (vbr) {
		gdb_vbr_vector = (void *)(vbr + 0x100);
		printk(KERN_NOTICE "Setting GDB trap vector to %p\n",
		       gdb_vbr_vector);
	} else
		printk(KERN_NOTICE "SH-BIOS not detected\n");
}

/**
 * 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

Annotation

Implementation Notes