1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * C interface for trapping into the standard LinuxSH BIOS. 4 * 5 * Copyright (C) 2000 Greg Banks, Mitch Davis 6 * Copyright (C) 1999, 2000 Niibe Yutaka 7 * Copyright (C) 2002 M. R. Brown 8 * Copyright (C) 2004 - 2010 Paul Mundt 9 */ 10 #include <linux/module.h> 11 #include <linux/console.h> 12 #include <linux/tty.h> 13 #include <linux/init.h> 14 #include <linux/io.h> 15 #include <linux/delay.h> 16 #include <asm/sh_bios.h> 17 18 #define BIOS_CALL_CONSOLE_WRITE 0 19 #define BIOS_CALL_ETH_NODE_ADDR 10 20 #define BIOS_CALL_SHUTDOWN 11 21 #define BIOS_CALL_GDB_DETACH 0xff 22 23 void *gdb_vbr_vector = NULL; 24 25 static inline long sh_bios_call(long func, long arg0, long arg1, long arg2, 26 long arg3) 27 { 28 register long r0 __asm__("r0") = func; 29 register long r4 __asm__("r4") = arg0; 30 register long r5 __asm__("r5") = arg1; 31 register long r6 __asm__("r6") = arg2; 32 register long r7 __asm__("r7") = arg3; 33 34 if (!gdb_vbr_vector) 35 return -ENOSYS; 36 37 __asm__ __volatile__("trapa #0x3f":"=z"(r0) 38 :"0"(r0), "r"(r4), "r"(r5), "r"(r6), "r"(r7) 39 :"memory"); 40 return r0; 41 } 42 43 void sh_bios_console_write(const char *buf, unsigned int len) 44 { 45 sh_bios_call(BIOS_CALL_CONSOLE_WRITE, (long)buf, (long)len, 0, 0); 46 } 47 48 void sh_bios_gdb_detach(void) 49 { 50 sh_bios_call(BIOS_CALL_GDB_DETACH, 0, 0, 0, 0); 51 } 52 EXPORT_SYMBOL_GPL(sh_bios_gdb_detach); 53 54 void sh_bios_get_node_addr(unsigned char *node_addr) 55 { 56 sh_bios_call(BIOS_CALL_ETH_NODE_ADDR, 0, (long)node_addr, 0, 0); 57 } 58 EXPORT_SYMBOL_GPL(sh_bios_get_node_addr); 59 60 void sh_bios_shutdown(unsigned int how) 61 { 62 sh_bios_call(BIOS_CALL_SHUTDOWN, how, 0, 0, 0); 63 } 64 65 /* 66 * Read the old value of the VBR register to initialise the vector 67 * through which debug and BIOS traps are delegated by the Linux trap 68 * handler. 69 */ 70 void sh_bios_vbr_init(void) 71 { 72 unsigned long vbr; 73 74 if (unlikely(gdb_vbr_vector)) 75 return; 76 77 __asm__ __volatile__ ("stc vbr, %0" : "=r" (vbr)); 78 79 if (vbr) { 80 gdb_vbr_vector = (void *)(vbr + 0x100); 81 printk(KERN_NOTICE "Setting GDB trap vector to %p\n", 82 gdb_vbr_vector); 83 } else 84 printk(KERN_NOTICE "SH-BIOS not detected\n"); 85 } 86 87 /** 88 * sh_bios_vbr_reload - Re-load the system VBR from the BIOS vector. 89 * 90 * This can be used by save/restore code to reinitialize the system VBR 91 * from the fixed BIOS VBR. A no-op if no BIOS VBR is known. 92 */ 93 void sh_bios_vbr_reload(void) 94 { 95 if (gdb_vbr_vector) 96 __asm__ __volatile__ ( 97 "ldc %0, vbr" 98 : 99 : "r" (((unsigned long) gdb_vbr_vector) - 0x100) 100 : "memory" 101 ); 102 } 103 104 #ifdef CONFIG_EARLY_PRINTK 105 /* 106 * Print a string through the BIOS 107 */ 108 static void sh_console_write(struct console *co, const char *s, 109 unsigned count) 110 { 111 sh_bios_console_write(s, count); 112 } 113 114 /* 115 * Setup initial baud/bits/parity. We do two things here: 116 * - construct a cflag setting for the first rs_open() 117 * - initialize the serial port 118 * Return non-zero if we didn't find a serial port. 119 */ 120 static int __init sh_console_setup(struct console *co, char *options) 121 { 122 int cflag = CREAD | HUPCL | CLOCAL; 123 124 /* 125 * Now construct a cflag setting. 126 * TODO: this is a totally bogus cflag, as we have 127 * no idea what serial settings the BIOS is using, or 128 * even if its using the serial port at all. 129 */ 130 cflag |= B115200 | CS8 | /*no parity*/0; 131 132 co->cflag = cflag; 133 134 return 0; 135 } 136 137 static struct console bios_console = { 138 .name = "bios", 139 .write = sh_console_write, 140 .setup = sh_console_setup, 141 .flags = CON_PRINTBUFFER, 142 .index = -1, 143 }; 144 145 static int __init setup_early_printk(char *buf) 146 { 147 int keep_early = 0; 148 149 if (!buf) 150 return 0; 151 152 if (strstr(buf, "keep")) 153 keep_early = 1; 154 155 if (!strncmp(buf, "bios", 4)) 156 early_console = &bios_console; 157 158 if (likely(early_console)) { 159 if (keep_early) 160 early_console->flags &= ~CON_BOOT; 161 else 162 early_console->flags |= CON_BOOT; 163 register_console(early_console); 164 } 165 166 return 0; 167 } 168 early_param("earlyprintk", setup_early_printk); 169 #endif 170