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/arch/sh/kernel/sh_bios.c

https://gitlab.com/teobaluta/opw
C | 172 lines | 108 code | 26 blank | 38 comment | 9 complexity | 25f45fc2b0c851cb12402df17614969b MD5 | raw file
  1/*
  2 *  C interface for trapping into the standard LinuxSH BIOS.
  3 *
  4 *  Copyright (C) 2000 Greg Banks, Mitch Davis
  5 *  Copyright (C) 1999, 2000  Niibe Yutaka
  6 *  Copyright (C) 2002  M. R. Brown
  7 *  Copyright (C) 2004 - 2010  Paul Mundt
  8 *
  9 * This file is subject to the terms and conditions of the GNU General Public
 10 * License.  See the file "COPYING" in the main directory of this archive
 11 * for more details.
 12 */
 13#include <linux/module.h>
 14#include <linux/console.h>
 15#include <linux/tty.h>
 16#include <linux/init.h>
 17#include <linux/io.h>
 18#include <linux/delay.h>
 19#include <asm/sh_bios.h>
 20
 21#define BIOS_CALL_CONSOLE_WRITE		0
 22#define BIOS_CALL_ETH_NODE_ADDR		10
 23#define BIOS_CALL_SHUTDOWN		11
 24#define BIOS_CALL_GDB_DETACH		0xff
 25
 26void *gdb_vbr_vector = NULL;
 27
 28static inline long sh_bios_call(long func, long arg0, long arg1, long arg2,
 29				    long arg3)
 30{
 31	register long r0 __asm__("r0") = func;
 32	register long r4 __asm__("r4") = arg0;
 33	register long r5 __asm__("r5") = arg1;
 34	register long r6 __asm__("r6") = arg2;
 35	register long r7 __asm__("r7") = arg3;
 36
 37	if (!gdb_vbr_vector)
 38		return -ENOSYS;
 39
 40	__asm__ __volatile__("trapa	#0x3f":"=z"(r0)
 41			     :"0"(r0), "r"(r4), "r"(r5), "r"(r6), "r"(r7)
 42			     :"memory");
 43	return r0;
 44}
 45
 46void sh_bios_console_write(const char *buf, unsigned int len)
 47{
 48	sh_bios_call(BIOS_CALL_CONSOLE_WRITE, (long)buf, (long)len, 0, 0);
 49}
 50
 51void sh_bios_gdb_detach(void)
 52{
 53	sh_bios_call(BIOS_CALL_GDB_DETACH, 0, 0, 0, 0);
 54}
 55EXPORT_SYMBOL_GPL(sh_bios_gdb_detach);
 56
 57void sh_bios_get_node_addr(unsigned char *node_addr)
 58{
 59	sh_bios_call(BIOS_CALL_ETH_NODE_ADDR, 0, (long)node_addr, 0, 0);
 60}
 61EXPORT_SYMBOL_GPL(sh_bios_get_node_addr);
 62
 63void sh_bios_shutdown(unsigned int how)
 64{
 65	sh_bios_call(BIOS_CALL_SHUTDOWN, how, 0, 0, 0);
 66}
 67
 68/*
 69 * Read the old value of the VBR register to initialise the vector
 70 * through which debug and BIOS traps are delegated by the Linux trap
 71 * handler.
 72 */
 73void sh_bios_vbr_init(void)
 74{
 75	unsigned long vbr;
 76
 77	if (unlikely(gdb_vbr_vector))
 78		return;
 79
 80	__asm__ __volatile__ ("stc vbr, %0" : "=r" (vbr));
 81
 82	if (vbr) {
 83		gdb_vbr_vector = (void *)(vbr + 0x100);
 84		printk(KERN_NOTICE "Setting GDB trap vector to %p\n",
 85		       gdb_vbr_vector);
 86	} else
 87		printk(KERN_NOTICE "SH-BIOS not detected\n");
 88}
 89
 90/**
 91 * sh_bios_vbr_reload - Re-load the system VBR from the BIOS vector.
 92 *
 93 * This can be used by save/restore code to reinitialize the system VBR
 94 * from the fixed BIOS VBR. A no-op if no BIOS VBR is known.
 95 */
 96void sh_bios_vbr_reload(void)
 97{
 98	if (gdb_vbr_vector)
 99		__asm__ __volatile__ (
100			"ldc %0, vbr"
101			:
102			: "r" (((unsigned long) gdb_vbr_vector) - 0x100)
103			: "memory"
104		);
105}
106
107#ifdef CONFIG_EARLY_PRINTK
108/*
109 *	Print a string through the BIOS
110 */
111static void sh_console_write(struct console *co, const char *s,
112				 unsigned count)
113{
114	sh_bios_console_write(s, count);
115}
116
117/*
118 *	Setup initial baud/bits/parity. We do two things here:
119 *	- construct a cflag setting for the first rs_open()
120 *	- initialize the serial port
121 *	Return non-zero if we didn't find a serial port.
122 */
123static int __init sh_console_setup(struct console *co, char *options)
124{
125	int	cflag = CREAD | HUPCL | CLOCAL;
126
127	/*
128	 *	Now construct a cflag setting.
129	 *	TODO: this is a totally bogus cflag, as we have
130	 *	no idea what serial settings the BIOS is using, or
131	 *	even if its using the serial port at all.
132	 */
133	cflag |= B115200 | CS8 | /*no parity*/0;
134
135	co->cflag = cflag;
136
137	return 0;
138}
139
140static struct console bios_console = {
141	.name		= "bios",
142	.write		= sh_console_write,
143	.setup		= sh_console_setup,
144	.flags		= CON_PRINTBUFFER,
145	.index		= -1,
146};
147
148static int __init setup_early_printk(char *buf)
149{
150	int keep_early = 0;
151
152	if (!buf)
153		return 0;
154
155	if (strstr(buf, "keep"))
156		keep_early = 1;
157
158	if (!strncmp(buf, "bios", 4))
159		early_console = &bios_console;
160
161	if (likely(early_console)) {
162		if (keep_early)
163			early_console->flags &= ~CON_BOOT;
164		else
165			early_console->flags |= CON_BOOT;
166		register_console(early_console);
167	}
168
169	return 0;
170}
171early_param("earlyprintk", setup_early_printk);
172#endif