117 lines
5.0 KiB
C
117 lines
5.0 KiB
C
/****************************************************************************
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* libc/termios/lib_cfsetspeed.c
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*
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* Copyright (C) 2012 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <gnutt@nuttx.org>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name NuttX nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <sys/types.h>
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#include <termios.h>
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#include <assert.h>
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/****************************************************************************
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* Pre-processor Definitions
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****************************************************************************/
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/****************************************************************************
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* Private Variables
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****************************************************************************/
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/****************************************************************************
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* Public Variables
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****************************************************************************/
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: cfsetspeed
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*
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* Descripton:
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* The cfsetspeed() function is a non-POSIX function that sets the baud
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* stored in the structure pointed to by termiosp to speed.
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*
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* There is no effect on the baud set in the hardware until a subsequent
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* successful call to tcsetattr() on the same termios structure.
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*
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* NOTE 1: NuttX does not control input/output baud independently. Both
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* must be the same. The POSIX standard interfaces, cfisetispeed() and
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* cfisetospeed() are defined to be cfsetspeed() in termios.h.
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*
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* NOTE 3: A consequence of NOTE 1 is that you should never attempt to
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* set the input and output baud to different values.
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*
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* Also, the following POSIX requirement cannot be supported: "If the input
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* baud rate stored in the termios structure pointed to by termios_p is 0,
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* the input baud rate given to the hardware will be the same as the output
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* baud rate stored in the termios structure."
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*
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* NOTE 2. In Nuttx, the speed_t is defined to be uint32_t and the baud
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* encodings of termios.h are the actual baud values themselves. Therefore,
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* any baud value can be provided as the speed argument here. However, if
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* you do so, your code will *NOT* be portable to other environments where
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* speed_t is smaller and where the termios.h baud values are encoded! To
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* avoid portability issues, use the baud definitions in termios.h!
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*
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* Linux, for example, would require this (also non-portable) sequence:
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*
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* cfsetispeed(termiosp, BOTHER);
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* termiosp->c_ispeed = baud;
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*
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* cfsetospeed(termiosp, BOTHER);
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* termiosp->c_ospeed = baud;
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*
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* Input Parameters:
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* termiosp - The termiosp argument is a pointer to a termios structure.
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* speed - The new input speed
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*
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* Returned Value:
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* Baud is not checked... OK is always returned (this is non-standard
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* behavior).
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*
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****************************************************************************/
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int cfsetspeed(FAR struct termios *termiosp, speed_t speed)
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{
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DEBUGASSERT(termiosp);
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termiosp->c_speed = speed;
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return OK;
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}
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