libcsupport/src/termios_setbestbaud.c

0001 /* SPDX-License-Identifier: BSD-2-Clause */
0002
0003 /*
0004  * Copyright (c) 2014 embedded brains GmbH & Co. KG
0005  *
0006  * Redistribution and use in source and binary forms, with or without
0007  * modification, are permitted provided that the following conditions
0008  * are met:
0009  * 1. Redistributions of source code must retain the above copyright
0010  *    notice, this list of conditions and the following disclaimer.
0011  * 2. Redistributions in binary form must reproduce the above copyright
0012  *    notice, this list of conditions and the following disclaimer in the
0013  *    documentation and/or other materials provided with the distribution.
0014  *
0015  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
0016  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
0017  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
0018  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
0019  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
0020  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
0021  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
0022  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
0023  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
0024  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
0025  * POSSIBILITY OF SUCH DAMAGE.
0026  */
0027
0028 #ifdef HAVE_CONFIG_H
0029 #include "config.h"
0030 #endif
0031
0032 #include <rtems/termiostypes.h>
0033
0034 void rtems_termios_set_best_baud(
0035   struct termios *term,
0036   uint32_t        baud
0037 )
0038 {
0039   const rtems_assoc_t *current = &rtems_termios_baud_table[ 0 ];
0040   const rtems_assoc_t *last = current;
0041   speed_t spd;
0042
0043   while ( current->name != NULL && current->local_value < baud ) {
0044     last = current;
0045     ++current;
0046   }
0047
0048   if ( current->name != NULL ) {
0049     uint32_t mid = (last->local_value + current->local_value) / UINT32_C( 2 );
0050
0051     spd = baud <= mid ? last->remote_value : current->remote_value;
0052   } else {
0053     spd = B460800;
0054   }
0055
0056   term->c_ispeed = spd;
0057   term->c_ospeed = spd;
0058 }