forked from Archive/PX4-Autopilot
123 lines
3.9 KiB
C
123 lines
3.9 KiB
C
/****************************************************************************
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*
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* Copyright (C) 2012 PX4 Development Team. All rights reserved.
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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 PX4 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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* @file hx_stream.h
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*
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* A simple serial line framing protocol based on HDLC
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* with 32-bit CRC protection.
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*/
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#ifndef _SYSTEMLIB_HX_STREAM_H
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#define _SYSTEMLIB_HX_STREAM_H
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#include <sys/types.h>
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#include "perf_counter.h"
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struct hx_stream;
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typedef struct hx_stream *hx_stream_t;
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#define HX_STREAM_MAX_FRAME 64
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typedef void (* hx_stream_rx_callback)(void *arg, const void *data, size_t length);
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__BEGIN_DECLS
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/**
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* Allocate a new hx_stream object.
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*
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* @param fd The file handle over which the protocol will
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* communicate.
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* @param callback Called when a frame is received.
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* @param callback_arg Passed to the callback.
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* @return A handle to the stream, or NULL if memory could
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* not be allocated.
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*/
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__EXPORT extern hx_stream_t hx_stream_init(int fd,
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hx_stream_rx_callback callback,
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void *arg);
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/**
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* Free a hx_stream object.
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*
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* @param stream A handle returned from hx_stream_init.
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*/
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__EXPORT extern void hx_stream_free(hx_stream_t stream);
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/**
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* Set performance counters for the stream.
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*
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* Any counter may be set to NULL to disable counting that datum.
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*
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* @param tx_frames Counter for transmitted frames.
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* @param rx_frames Counter for received frames.
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* @param rx_errors Counter for short and corrupt received frames.
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*/
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__EXPORT extern void hx_stream_set_counters(hx_stream_t stream,
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perf_counter_t tx_frames,
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perf_counter_t rx_frames,
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perf_counter_t rx_errors);
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/**
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* Send a frame.
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*
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* This function will block until all frame bytes are sent if
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* the descriptor passed to hx_stream_init is marked blocking,
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* otherwise it will return -1 (but may transmit a
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* runt frame at the same time).
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*
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* @todo Handling of non-blocking streams needs to be better.
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*
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* @param stream A handle returned from hx_stream_init.
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* @param data Pointer to the data to send.
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* @param count The number of bytes to send.
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* @return Zero on success, -errno on error.
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*/
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__EXPORT extern int hx_stream_send(hx_stream_t stream,
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const void *data,
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size_t count);
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/**
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* Handle a byte from the stream.
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*
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* @param stream A handle returned from hx_stream_init.
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* @param c The character to process.
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*/
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__EXPORT extern void hx_stream_rx(hx_stream_t stream,
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uint8_t c);
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__END_DECLS
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#endif
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