aboutsummaryrefslogtreecommitdiff
path: root/libbb/speed_table.c
blob: cf7101e645c98a8fbcd39193c404e8b487ba46fa (plain)
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
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
/* vi: set sw=4 ts=4: */
/*
 * compact speed_t <-> speed functions for busybox
 *
 * Copyright (C) 2003  Manuel Novoa III  <mjn3@codepoet.org>
 *
 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
 */
#include "libbb.h"

struct speed_map {
#if defined __FreeBSD__ \
 || (defined B115200  && B115200  > 0xffff) \
 || (defined B230400  && B230400  > 0xffff) \
 || (defined B460800  && B460800  > 0xffff) \
 || (defined B921600  && B921600  > 0xffff) \
 || (defined B1152000 && B1152000 > 0xffff) \
 || (defined B1000000 && B1000000 > 0xffff) \
 || (defined B2000000 && B2000000 > 0xffff) \
 || (defined B3000000 && B3000000 > 0xffff) \
 || (defined B4000000 && B4000000 > 0xffff)
	/* On FreeBSD, B<num> constants don't fit into a short */
	unsigned speed;
#else
	unsigned short speed;
#endif
	unsigned short value;
};

/* On Linux, Bxx constants are 0..15 (up to B38400) and 0x1001..0x100f */
static const struct speed_map speeds[] ALIGN4 = {
	{B0, 0},
	{B50, 50},
	{B75, 75},
	{B110, 110},
	{B134, 134},
	{B150, 150},
	{B200, 200},
	{B300, 300},
	{B600, 600},
	{B1200, 1200},
	{B1800, 1800},
	{B2400, 2400},
	{B4800, 4800},
	{B9600, 9600},
#ifdef B19200
	{B19200, 19200},
#elif defined(EXTA)
	{EXTA,   19200},
#endif
/* 19200 = 0x4b00 */
/* 38400 = 0x9600, this value would use bit#15 if not "/200" encoded: */
#ifdef B38400
	{B38400, 38400/200 + 0x8000u},
#elif defined(EXTB)
	{EXTB,   38400/200 + 0x8000u},
#endif
#ifdef B57600
	{B57600, 57600/200 + 0x8000u},
#endif
#ifdef B115200
	{B115200, 115200/200 + 0x8000u},
#endif
#ifdef B230400
	{B230400, 230400/200 + 0x8000u},
#endif
#ifdef B460800
	{B460800, 460800/200 + 0x8000u},
#endif
#ifdef B576000
	{B576000, 576000/200 + 0x8000u},
#endif
#ifdef B921600
	{B921600, 921600/200 + 0x8000u},
#endif
#ifdef B1152000
	{B1152000, 1152000/200 + 0x8000u},
#endif

#ifdef B500000
	{B500000,   500000/200 + 0x8000u},
#endif
#ifdef B1000000
	{B1000000, 1000000/200 + 0x8000u},
#endif
#ifdef B1500000
	{B1500000, 1500000/200 + 0x8000u},
#endif
#ifdef B2000000
	{B2000000, 2000000/200 + 0x8000u},
#endif
#ifdef B2500000
	{B2500000, 2500000/200 + 0x8000u},
#endif
#ifdef B3000000
	{B3000000, 3000000/200 + 0x8000u},
#endif
#ifdef B3500000
	{B3500000, 3500000/200 + 0x8000u},
#endif
#ifdef B4000000
	{B4000000, 4000000/200 + 0x8000u},
#endif
/* 4000000/200 = 0x4e20, bit#15 still does not interfere with the value */
/* (can use /800 if higher speeds would appear, /1600 won't work for B500000) */
};

/*
 * TODO: maybe we can just bite the bullet, ditch the table and use termios2
 * Linux API (supports arbitrary baud rates, no Bxxxx mess needed)? Example:
 *
 * #include <asm/termios.h>
 * #include <asm/ioctls.h>
 * struct termios2 t;
 * ioctl(fd, TCGETS2, &t);
 * t.c_ospeed = t.c_ispeed = 543210;
 * t.c_cflag &= ~CBAUD;
 * t.c_cflag |= BOTHER;
 * ioctl(fd, TCSETS2, &t);
 */

enum { NUM_SPEEDS = ARRAY_SIZE(speeds) };

unsigned FAST_FUNC tty_baud_to_value(speed_t speed)
{
	int i = 0;

	do {
		if (speed == speeds[i].speed) {
			if (speeds[i].value & 0x8000u) {
				return ((unsigned)(speeds[i].value) & 0x7fffU) * 200;
			}
			return speeds[i].value;
		}
	} while (++i < NUM_SPEEDS);

	return 0;
}

speed_t FAST_FUNC tty_value_to_baud(unsigned int value)
{
	int i = 0;

	do {
		if (value == tty_baud_to_value(speeds[i].speed)) {
			return speeds[i].speed;
		}
	} while (++i < NUM_SPEEDS);

	return (speed_t) - 1;
}

#if 0
/* testing code */
#include <stdio.h>

int main(void)
{
	unsigned long v;
	speed_t s;

	for (v = 0 ; v < 1000000; v++) {
		s = tty_value_to_baud(v);
		if (s == (speed_t) -1) {
			continue;
		}
		printf("v = %lu -- s = %0lo\n", v, (unsigned long) s);
	}

	printf("-------------------------------\n");

	for (s = 0 ; s < 010017+1; s++) {
		v = tty_baud_to_value(s);
		if (!v) {
			continue;
		}
		printf("v = %lu -- s = %0lo\n", v, (unsigned long) s);
	}

	return 0;
}
#endif