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 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 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 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 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 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 */ 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 */ 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 */ 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 */ 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 }; 147 148 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