1 // SPDX-License-Identifier: GPL-2.0
2 #include "wakeup.h"
3 #include "boot.h"
4
5 static void udelay(int loops)
6 {
7 while (loops--)
8 io_delay(); /* Approximately 1 us */
9 }
10
11 static void beep(unsigned int hz)
12 {
13 u8 enable;
14
15 if (!hz) {
16 enable = 0x00; /* Turn off speaker */
17 } else {
18 u16 div = 1193181/hz;
19
20 outb(0xb6, 0x43); /* Ctr 2, squarewave, load, binary */
21 io_delay();
22 outb(div, 0x42); /* LSB of counter */
23 io_delay();
24 outb(div >> 8, 0x42); /* MSB of counter */
25 io_delay();
26
27 enable = 0x03; /* Turn on speaker */
28 }
29 inb(0x61); /* Dummy read of System Control Port B */
30 io_delay();
31 outb(enable, 0x61); /* Enable timer 2 output to speaker */
32 io_delay();
33 }
34
35 #define DOT_HZ 880
36 #define DASH_HZ 587
37 #define US_PER_DOT 125000
38
39 /* Okay, this is totally silly, but it's kind of fun. */
40 static void send_morse(const char *pattern)
41 {
42 char s;
43
44 while ((s = *pattern++)) {
45 switch (s) {
46 case '.':
47 beep(DOT_HZ);
48 udelay(US_PER_DOT);
49 beep(0);
50 udelay(US_PER_DOT);
51 break;
52 case '-':
53 beep(DASH_HZ);
54 udelay(US_PER_DOT * 3);
55 beep(0);
56 udelay(US_PER_DOT);
57 break;
58 default: /* Assume it's a space */
59 udelay(US_PER_DOT * 3);
60 break;
61 }
62 }
63 }
64
65 void main(void)
66 {
67 /* Kill machine if structures are wrong */
68 if (wakeup_header.real_magic != 0x12345678)
69 while (1)
70 ;
71
72 if (wakeup_header.realmode_flags & 4)
73 send_morse("...-");
74
75 if (wakeup_header.realmode_flags & 1)
76 asm volatile("lcallw $0xc000,$3");
77
78 if (wakeup_header.realmode_flags & 2) {
79 /* Need to call BIOS */
80 probe_cards(0);
81 set_mode(wakeup_header.video_mode);
82 }
83 }