arch/sh/kernel/sh_bios.c

   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