wakemain.c

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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);
    }
}