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
26 void *gdb_vbr_vector = NULL;
27
sh_bios_call(long func,long arg0,long arg1,long arg2,long arg3)28 static 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
sh_bios_console_write(const char * buf,unsigned int len)46 void 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
sh_bios_gdb_detach(void)51 void sh_bios_gdb_detach(void)
52 {
53 sh_bios_call(BIOS_CALL_GDB_DETACH, 0, 0, 0, 0);
54 }
55 EXPORT_SYMBOL_GPL(sh_bios_gdb_detach);
56
sh_bios_get_node_addr(unsigned char * node_addr)57 void 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 }
61 EXPORT_SYMBOL_GPL(sh_bios_get_node_addr);
62
sh_bios_shutdown(unsigned int how)63 void 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 */
sh_bios_vbr_init(void)73 void 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 */
sh_bios_vbr_reload(void)96 void 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 */
sh_console_write(struct console * co,const char * s,unsigned count)111 static 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 */
sh_console_setup(struct console * co,char * options)123 static 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
140 static 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
setup_early_printk(char * buf)148 static 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 }
171 early_param("earlyprintk", setup_early_printk);
172 #endif
173