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kernel/linux-rt-4.4.41/arch/x86/realmode/rm/wakemain.c 1.5 KB
5113f6f70   김현기   kernel add
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  #include "wakeup.h"
  #include "boot.h"
  
  static void udelay(int loops)
  {
  	while (loops--)
  		io_delay();	/* Approximately 1 us */
  }
  
  static void beep(unsigned int hz)
  {
  	u8 enable;
  
  	if (!hz) {
  		enable = 0x00;		/* Turn off speaker */
  	} else {
  		u16 div = 1193181/hz;
  
  		outb(0xb6, 0x43);	/* Ctr 2, squarewave, load, binary */
  		io_delay();
  		outb(div, 0x42);	/* LSB of counter */
  		io_delay();
  		outb(div >> 8, 0x42);	/* MSB of counter */
  		io_delay();
  
  		enable = 0x03;		/* Turn on speaker */
  	}
  	inb(0x61);		/* Dummy read of System Control Port B */
  	io_delay();
  	outb(enable, 0x61);	/* Enable timer 2 output to speaker */
  	io_delay();
  }
  
  #define DOT_HZ		880
  #define DASH_HZ		587
  #define US_PER_DOT	125000
  
  /* Okay, this is totally silly, but it's kind of fun. */
  static void send_morse(const char *pattern)
  {
  	char s;
  
  	while ((s = *pattern++)) {
  		switch (s) {
  		case '.':
  			beep(DOT_HZ);
  			udelay(US_PER_DOT);
  			beep(0);
  			udelay(US_PER_DOT);
  			break;
  		case '-':
  			beep(DASH_HZ);
  			udelay(US_PER_DOT * 3);
  			beep(0);
  			udelay(US_PER_DOT);
  			break;
  		default:	/* Assume it's a space */
  			udelay(US_PER_DOT * 3);
  			break;
  		}
  	}
  }
  
  void main(void)
  {
  	/* Kill machine if structures are wrong */
  	if (wakeup_header.real_magic != 0x12345678)
  		while (1)
  			;
  
  	if (wakeup_header.realmode_flags & 4)
  		send_morse("...-");
  
  	if (wakeup_header.realmode_flags & 1)
  		asm volatile("lcallw   $0xc000,$3");
  
  	if (wakeup_header.realmode_flags & 2) {
  		/* Need to call BIOS */
  		probe_cards(0);
  		set_mode(wakeup_header.video_mode);
  	}
  }