linux/linux-5.4.31/arch/x86/realmode/rm/wakemain.c

84 lines
1.5 KiB
C

// SPDX-License-Identifier: GPL-2.0
#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);
}
}