1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
|
// SPDX-License-Identifier: GPL-2.0-only
/* -*- linux-c -*- ------------------------------------------------------- *
*
* Copyright (C) 1991, 1992 Linus Torvalds
* Copyright 2007 rPath, Inc. - All Rights Reserved
* Copyright 2009 Intel Corporation; author H. Peter Anvin
*
* ----------------------------------------------------------------------- */
/*
* Very simple screen and serial I/O
*/
#include "boot.h"
int early_serial_base;
#define XMTRDY 0x20
#define TXR 0 /* Transmit register (WRITE) */
#define LSR 5 /* Line Status */
/*
* These functions are in .inittext so they can be used to signal
* error during initialization.
*/
static void __attribute__((section(".inittext"))) serial_putchar(int ch)
{
unsigned timeout = 0xffff;
while ((inb(early_serial_base + LSR) & XMTRDY) == 0 && --timeout)
cpu_relax();
outb(ch, early_serial_base + TXR);
}
static void __attribute__((section(".inittext"))) bios_putchar(int ch)
{
struct biosregs ireg;
initregs(&ireg);
ireg.bx = 0x0007;
ireg.cx = 0x0001;
ireg.ah = 0x0e;
ireg.al = ch;
intcall(0x10, &ireg, NULL);
}
void __attribute__((section(".inittext"))) putchar(int ch)
{
if (ch == '\n')
putchar('\r'); /* \n -> \r\n */
bios_putchar(ch);
if (early_serial_base != 0)
serial_putchar(ch);
}
void __attribute__((section(".inittext"))) puts(const char *str)
{
while (*str)
putchar(*str++);
}
/*
* Read the CMOS clock through the BIOS, and return the
* seconds in BCD.
*/
static u8 gettime(void)
{
struct biosregs ireg, oreg;
initregs(&ireg);
ireg.ah = 0x02;
intcall(0x1a, &ireg, &oreg);
return oreg.dh;
}
/*
* Read from the keyboard
*/
int getchar(void)
{
struct biosregs ireg, oreg;
initregs(&ireg);
/* ireg.ah = 0x00; */
intcall(0x16, &ireg, &oreg);
return oreg.al;
}
static int kbd_pending(void)
{
struct biosregs ireg, oreg;
initregs(&ireg);
ireg.ah = 0x01;
intcall(0x16, &ireg, &oreg);
return !(oreg.eflags & X86_EFLAGS_ZF);
}
void kbd_flush(void)
{
for (;;) {
if (!kbd_pending())
break;
getchar();
}
}
int getchar_timeout(void)
{
int cnt = 30;
int t0, t1;
t0 = gettime();
while (cnt) {
if (kbd_pending())
return getchar();
t1 = gettime();
if (t0 != t1) {
cnt--;
t0 = t1;
}
}
return 0; /* Timeout! */
}
|
