arch/x86/kernel/acpi/realmode/wakemain.c

   1 #include "wakeup.h"
   2 #include "boot.h"
   3
   4 static void udelay(int loops)
   5 {
   6         while (loops--)
   7                 io_delay();     /* Approximately 1 us */
   8 }
   9
  10 static void beep(unsigned int hz)
  11 {
  12         u8 enable;
  13
  14         if (!hz) {
  15                 enable = 0x00;          /* Turn off speaker */
  16         } else {
  17                 u16 div = 1193181/hz;
  18
  19                 outb(0xb6, 0x43);       /* Ctr 2, squarewave, load, binary */
  20                 io_delay();
  21                 outb(div, 0x42);        /* LSB of counter */
  22                 io_delay();
  23                 outb(div >> 8, 0x42);   /* MSB of counter */
  24                 io_delay();
  25
  26                 enable = 0x03;          /* Turn on speaker */
  27         }
  28         inb(0x61);              /* Dummy read of System Control Port B */
  29         io_delay();
  30         outb(enable, 0x61);     /* Enable timer 2 output to speaker */
  31         io_delay();
  32 }
  33
  34 #define DOT_HZ          880
  35 #define DASH_HZ         587
  36 #define US_PER_DOT      125000
  37
  38 /* Okay, this is totally silly, but it's kind of fun. */
  39 static void send_morse(const char *pattern)
  40 {
  41         char s;
  42
  43         while ((s = *pattern++)) {
  44                 switch (s) {
  45                 case '.':
  46                         beep(DOT_HZ);
  47                         udelay(US_PER_DOT);
  48                         beep(0);
  49                         udelay(US_PER_DOT);
  50                         break;
  51                 case '-':
  52                         beep(DASH_HZ);
  53                         udelay(US_PER_DOT * 3);
  54                         beep(0);
  55                         udelay(US_PER_DOT);
  56                         break;
  57                 default:        /* Assume it's a space */
  58                         udelay(US_PER_DOT * 3);
  59                         break;
  60                 }
  61         }
  62 }
  63
  64 void main(void)
  65 {
  66         /* Kill machine if structures are wrong */
  67         if (wakeup_header.real_magic != 0x12345678)
  68                 while (1);
  69
  70         if (wakeup_header.realmode_flags & 4)
  71                 send_morse("...-");
  72
  73         if (wakeup_header.realmode_flags & 1)
  74                 asm volatile("lcallw   $0xc000,$3");
  75
  76         if (wakeup_header.realmode_flags & 2) {
  77                 /* Need to call BIOS */
  78                 probe_cards(0);
  79                 set_mode(wakeup_header.video_mode);
  80         }
  81 }