LXR linux/arch/sh/kernel/sh

   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/*
 108 *      Print a string through the BIOS
 109 */
 110static void sh_console_write(struct console *co, const char *s,
 111                                 unsigned count)
 112{
 113        sh_bios_console_write(s, count);
 114}
 115
 116/*
 117 *      Setup initial baud/bits/parity. We do two things here:
 118 *      - construct a cflag setting for the first rs_open()
 119 *      - initialize the serial port
 120 *      Return non-zero if we didn't find a serial port.
 121 */
 122static int __init sh_console_setup(struct console *co, char *options)
 123{
 124        int     cflag = CREAD | HUPCL | CLOCAL;
 125
 126        /*
 127         *      Now construct a cflag setting.
 128         *      TODO: this is a totally bogus cflag, as we have
 129         *      no idea what serial settings the BIOS is using, or
 130         *      even if its using the serial port at all.
 131         */
 132        cflag |= B115200 | CS8 | /*no parity*/0;
 133
 134        co->cflag = cflag;
 135
 136        return 0;
 137}
 138
 139static struct console bios_console = {
 140        .name           = "bios",
 141        .write          = sh_console_write,
 142        .setup          = sh_console_setup,
 143        .flags          = CON_PRINTBUFFER,
 144        .index          = -1,
 145};
 146
 147static struct console *early_console;
 148
 149static int __init setup_early_printk(char *buf)
 150{
 151        int keep_early = 0;
 152
 153        if (!buf)
 154                return 0;
 155
 156        if (strstr(buf, "keep"))
 157                keep_early = 1;
 158
 159        if (!strncmp(buf, "bios", 4))
 160                early_console = &bios_console;
 161
 162        if (likely(early_console)) {
 163                if (keep_early)
 164                        early_console->flags &= ~CON_BOOT;
 165                else
 166                        early_console->flags |= CON_BOOT;
 167                register_console(early_console);
 168        }
 169
 170        return 0;
 171}
 172early_param("earlyprintk", setup_early_printk);
 173