LXR busybox/libbb/speed

   1/* vi: set sw=4 ts=4: */
   2/*
   3 * compact speed_t <-> speed functions for busybox
   4 *
   5 * Copyright (C) 2003  Manuel Novoa III  <mjn3@codepoet.org>
   6 *
   7 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
   8 */
   9#include "libbb.h"
  10
  11struct speed_map {
  12#if defined __FreeBSD__ \
  13 || (defined B115200  && B115200  > 0xffff) \
  14 || (defined B230400  && B230400  > 0xffff) \
  15 || (defined B460800  && B460800  > 0xffff) \
  16 || (defined B921600  && B921600  > 0xffff) \
  17 || (defined B1152000 && B1152000 > 0xffff) \
  18 || (defined B1000000 && B1000000 > 0xffff) \
  19 || (defined B2000000 && B2000000 > 0xffff) \
  20 || (defined B3000000 && B3000000 > 0xffff) \
  21 || (defined B4000000 && B4000000 > 0xffff)
  22        /* On FreeBSD, B<num> constants don't fit into a short */
  23        unsigned speed;
  24#else
  25        unsigned short speed;
  26#endif
  27        unsigned short value;
  28};
  29
  30/* On Linux, Bxx constants are 0..15 (up to B38400) and 0x1001..0x100f */
  31static const struct speed_map speeds[] ALIGN4 = {
  32        {B0, 0},
  33        {B50, 50},
  34        {B75, 75},
  35        {B110, 110},
  36        {B134, 134},
  37        {B150, 150},
  38        {B200, 200},
  39        {B300, 300},
  40        {B600, 600},
  41        {B1200, 1200},
  42        {B1800, 1800},
  43        {B2400, 2400},
  44        {B4800, 4800},
  45        {B9600, 9600},
  46#ifdef B19200
  47        {B19200, 19200},
  48#elif defined(EXTA)
  49        {EXTA,   19200},
  50#endif
  51/* 19200 = 0x4b00 */
  52/* 38400 = 0x9600, this value would use bit#15 if not "/200" encoded: */
  53#ifdef B38400
  54        {B38400, 38400/200 + 0x8000u},
  55#elif defined(EXTB)
  56        {EXTB,   38400/200 + 0x8000u},
  57#endif
  58#ifdef B57600
  59        {B57600, 57600/200 + 0x8000u},
  60#endif
  61#ifdef B115200
  62        {B115200, 115200/200 + 0x8000u},
  63#endif
  64#ifdef B230400
  65        {B230400, 230400/200 + 0x8000u},
  66#endif
  67#ifdef B460800
  68        {B460800, 460800/200 + 0x8000u},
  69#endif
  70#ifdef B576000
  71        {B576000, 576000/200 + 0x8000u},
  72#endif
  73#ifdef B921600
  74        {B921600, 921600/200 + 0x8000u},
  75#endif
  76#ifdef B1152000
  77        {B1152000, 1152000/200 + 0x8000u},
  78#endif
  79
  80#ifdef B500000
  81        {B500000,   500000/200 + 0x8000u},
  82#endif
  83#ifdef B1000000
  84        {B1000000, 1000000/200 + 0x8000u},
  85#endif
  86#ifdef B1500000
  87        {B1500000, 1500000/200 + 0x8000u},
  88#endif
  89#ifdef B2000000
  90        {B2000000, 2000000/200 + 0x8000u},
  91#endif
  92#ifdef B2500000
  93        {B2500000, 2500000/200 + 0x8000u},
  94#endif
  95#ifdef B3000000
  96        {B3000000, 3000000/200 + 0x8000u},
  97#endif
  98#ifdef B3500000
  99        {B3500000, 3500000/200 + 0x8000u},
 100#endif
 101#ifdef B4000000
 102        {B4000000, 4000000/200 + 0x8000u},
 103#endif
 104/* 4000000/200 = 0x4e20, bit#15 still does not interfere with the value */
 105/* (can use /800 if higher speeds would appear, /1600 won't work for B500000) */
 106};
 107
 108/*
 109 * TODO: maybe we can just bite the bullet, ditch the table and use termios2
 110 * Linux API (supports arbitrary baud rates, no Bxxxx mess needed)? Example:
 111 *
 112 * #include <asm/termios.h>
 113 * #include <asm/ioctls.h>
 114 * struct termios2 t;
 115 * ioctl(fd, TCGETS2, &t);
 116 * t.c_ospeed = t.c_ispeed = 543210;
 117 * t.c_cflag &= ~CBAUD;
 118 * t.c_cflag |= BOTHER;
 119 * ioctl(fd, TCSETS2, &t);
 120 */
 121
 122enum { NUM_SPEEDS = ARRAY_SIZE(speeds) };
 123
 124unsigned FAST_FUNC tty_baud_to_value(speed_t speed)
 125{
 126        int i = 0;
 127
 128        do {
 129                if (speed == speeds[i].speed) {
 130                        if (speeds[i].value & 0x8000u) {
 131                                return ((unsigned)(speeds[i].value) & 0x7fffU) * 200;
 132                        }
 133                        return speeds[i].value;
 134                }
 135        } while (++i < NUM_SPEEDS);
 136
 137        return 0;
 138}
 139
 140speed_t FAST_FUNC tty_value_to_baud(unsigned int value)
 141{
 142        int i = 0;
 143
 144        do {
 145                if (value == tty_baud_to_value(speeds[i].speed)) {
 146                        return speeds[i].speed;
 147                }
 148        } while (++i < NUM_SPEEDS);
 149
 150        return (speed_t) - 1;
 151}
 152
 153#if 0
 154/* testing code */
 155#include <stdio.h>
 156
 157int main(void)
 158{
 159        unsigned long v;
 160        speed_t s;
 161
 162        for (v = 0 ; v < 1000000; v++) {
 163                s = tty_value_to_baud(v);
 164                if (s == (speed_t) -1) {
 165                        continue;
 166                }
 167                printf("v = %lu -- s = %0lo\n", v, (unsigned long) s);
 168        }
 169
 170        printf("-------------------------------\n");
 171
 172        for (s = 0 ; s < 010017+1; s++) {
 173                v = tty_baud_to_value(s);
 174                if (!v) {
 175                        continue;
 176                }
 177                printf("v = %lu -- s = %0lo\n", v, (unsigned long) s);
 178        }
 179
 180        return 0;
 181}
 182#endif
 183