353 lines
14 KiB
C
353 lines
14 KiB
C
/*
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ChibiOS/RT - Copyright (C) 2006,2007,2008,2009,2010,
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2011 Giovanni Di Sirio.
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This file is part of ChibiOS/RT.
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ChibiOS/RT is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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ChibiOS/RT is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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/**
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* @file chioch.h
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* @brief I/O channels.
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* @details This header defines abstract interfaces useful to access generic
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* I/O resources in a standardized way.
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*
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* @addtogroup io_channels
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* @details This module defines an abstract interface for I/O channels by
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* extending the @p BaseSequentialStream interface. Note that no code
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* is present, I/O channels are just abstract interface like
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* structures, you should look at the systems as to a set of abstract
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* C++ classes (even if written in C). Specific device drivers can
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* use/extend the interface and implement them.<br>
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* This system has the advantage to make the access to channels
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* independent from the implementation logic.
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* @{
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*/
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#ifndef _CHIOCH_H_
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#define _CHIOCH_H_
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/**
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* @brief @p BaseChannel specific methods.
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*/
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#define _base_channel_methods \
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_base_sequential_stream_methods \
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/* Channel output check.*/ \
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bool_t (*putwouldblock)(void *instance); \
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/* Channel input check.*/ \
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bool_t (*getwouldblock)(void *instance); \
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/* Channel put method with timeout specification.*/ \
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msg_t (*put)(void *instance, uint8_t b, systime_t time); \
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/* Channel get method with timeout specification.*/ \
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msg_t (*get)(void *instance, systime_t time); \
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/* Channel write method with timeout specification.*/ \
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size_t (*writet)(void *instance, const uint8_t *bp, \
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size_t n, systime_t time); \
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/* Channel read method with timeout specification.*/ \
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size_t (*readt)(void *instance, uint8_t *bp, size_t n, systime_t time);
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/**
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* @brief @p BaseChannel specific data.
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* @note It is empty because @p BaseChannel is only an interface without
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* implementation.
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*/
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#define _base_channel_data \
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_base_sequential_stream_data
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/**
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* @brief @p BaseChannel virtual methods table.
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*/
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struct BaseChannelVMT { \
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_base_channel_methods \
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};
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/**
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* @extends BaseSequentialStream
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*
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* @brief Base channel class.
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* @details This class represents a generic, byte-wide, I/O channel. This class
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* introduces generic I/O primitives with timeout specification.
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*/
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typedef struct {
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/** @brief Virtual Methods Table.*/
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const struct BaseChannelVMT *vmt;
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_base_channel_data
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} BaseChannel;
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/**
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* @brief Channel output check.
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* @details This function verifies if a subsequent put/write operation would
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* block.
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*
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* @param[in] ip pointer to a @p BaseChannel or derived class
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* @return The output queue status.
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* @retval FALSE if the output queue has space and would not block a
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* write operation.
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* @retval TRUE if the output queue is full and would block a write
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* operation.
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*
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* @api
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*/
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#define chIOPutWouldBlock(ip) ((ip)->vmt->putwouldblock(ip))
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/**
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* @brief Channel input check.
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* @details This function verifies if a subsequent get/read operation would
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* block.
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*
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* @param[in] ip pointer to a @p BaseChannel or derived class
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* @return The input queue status.
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* @retval FALSE if the input queue contains data and would not block a
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* read operation.
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* @retval TRUE if the input queue is empty and would block a read
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* operation.
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*
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* @api
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*/
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#define chIOGetWouldBlock(ip) ((ip)->vmt->getwouldblock(ip))
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/**
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* @brief Channel blocking byte write.
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* @details This function writes a byte value to a channel. If the channel
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* is not ready to accept data then the calling thread is suspended.
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*
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* @param[in] ip pointer to a @p BaseChannel or derived class
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* @param[in] b the byte value to be written to the channel
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* @return The operation status.
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* @retval Q_OK if the operation succeeded.
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* @retval Q_RESET if the channel associated queue (if any) was reset.
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*
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* @api
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*/
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#define chIOPut(ip, b) ((ip)->vmt->put(ip, b, TIME_INFINITE))
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/**
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* @brief Channel blocking byte write with timeout.
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* @details This function writes a byte value to a channel. If the channel
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* is not ready to accept data then the calling thread is suspended.
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*
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* @param[in] ip pointer to a @p BaseChannel or derived class
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* @param[in] b the byte value to be written to the channel
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* @param[in] time the number of ticks before the operation timeouts,
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* the following special values are allowed:
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* - @a TIME_IMMEDIATE immediate timeout.
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* - @a TIME_INFINITE no timeout.
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* .
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* @return The operation status.
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* @retval Q_OK if the operation succeeded.
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* @retval Q_TIMEOUT if the specified time expired.
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* @retval Q_RESET if the channel associated queue (if any) was reset.
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*
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* @api
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*/
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#define chIOPutTimeout(ip, b, time) ((ip)->vmt->put(ip, b, time))
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/**
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* @brief Channel blocking byte read.
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* @details This function reads a byte value from a channel. If the data
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* is not available then the calling thread is suspended.
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*
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* @param[in] ip pointer to a @p BaseChannel or derived class
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* @return A byte value from the queue.
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* @retval Q_RESET if the channel associated queue (if any) has been
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* reset.
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*
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* @api
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*/
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#define chIOGet(ip) ((ip)->vmt->get(ip, TIME_INFINITE))
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/**
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* @brief Channel blocking byte read with timeout.
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* @details This function reads a byte value from a channel. If the data
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* is not available then the calling thread is suspended.
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*
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* @param[in] ip pointer to a @p BaseChannel or derived class
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* @param[in] time the number of ticks before the operation timeouts,
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* the following special values are allowed:
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* - @a TIME_IMMEDIATE immediate timeout.
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* - @a TIME_INFINITE no timeout.
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* .
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* @return A byte value from the queue.
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* @retval Q_TIMEOUT if the specified time expired.
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* @retval Q_RESET if the channel associated queue (if any) has been
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* reset.
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*
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* @api
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*/
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#define chIOGetTimeout(ip, time) ((ip)->vmt->get(ip, time))
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/**
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* @brief Channel blocking write with timeout.
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* @details The function writes data from a buffer to a channel. If the channel
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* is not ready to accept data then the calling thread is suspended.
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*
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* @param[in] ip pointer to a @p BaseChannel or derived class
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* @param[out] bp pointer to the data buffer
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* @param[in] n the maximum amount of data to be transferred
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* @param[in] time the number of ticks before the operation timeouts,
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* the following special values are allowed:
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* - @a TIME_IMMEDIATE immediate timeout.
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* - @a TIME_INFINITE no timeout.
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* .
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* @return The number of bytes transferred.
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*
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* @api
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*/
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#define chIOWriteTimeout(ip, bp, n, time) \
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((ip)->vmt->writet(ip, bp, n, time))
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/**
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* @brief Channel blocking read with timeout.
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* @details The function reads data from a channel into a buffer. If the data
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* is not available then the calling thread is suspended.
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*
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* @param[in] ip pointer to a @p BaseChannel or derived class
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* @param[in] bp pointer to the data buffer
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* @param[in] n the maximum amount of data to be transferred
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* @param[in] time the number of ticks before the operation timeouts,
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* the following special values are allowed:
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* - @a TIME_IMMEDIATE immediate timeout.
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* - @a TIME_INFINITE no timeout.
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* .
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* @return The number of bytes transferred.
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*
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* @api
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*/
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#define chIOReadTimeout(ip, bp, n, time) \
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((ip)->vmt->readt(ip, bp, n, time))
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#if CH_USE_EVENTS
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/** @brief No pending conditions.*/
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#define IO_NO_ERROR 0
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/** @brief Connection happened.*/
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#define IO_CONNECTED 1
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/** @brief Disconnection happened.*/
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#define IO_DISCONNECTED 2
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/** @brief Data available in the input queue.*/
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#define IO_INPUT_AVAILABLE 4
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/** @brief Output queue empty.*/
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#define IO_OUTPUT_EMPTY 8
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/** @brief Transmission end.*/
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#define IO_TRANSMISSION_END 16
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/**
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* @brief Type of an I/O condition flags mask.
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*/
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typedef uint_fast16_t ioflags_t;
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/**
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* @brief @p BaseAsynchronousChannel specific methods.
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*/
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#define _base_asynchronous_channel_methods \
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_base_channel_methods \
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/* Channel read method with timeout specification.*/ \
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ioflags_t (*getflags)(void *instance);
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/**
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* @brief @p BaseAsynchronousChannel specific data.
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*/
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#define _base_asynchronous_channel_data \
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_base_channel_data \
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/* I/O condition event source.*/ \
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EventSource event; \
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/* I/O condition flags.*/ \
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ioflags_t flags;
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/**
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* @brief @p BaseAsynchronousChannel virtual methods table.
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*/
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struct BaseAsynchronousChannelVMT {
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_base_asynchronous_channel_methods
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};
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/**
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* @extends BaseChannel
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*
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* @brief Base asynchronous channel class.
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* @details This class extends @p BaseChannel by adding event sources fields
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* for asynchronous I/O for use in an event-driven environment.
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*/
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typedef struct {
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/** @brief Virtual Methods Table.*/
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const struct BaseAsynchronousChannelVMT *vmt;
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_base_asynchronous_channel_data
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} BaseAsynchronousChannel;
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/**
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* @brief Returns the I/O condition event source.
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* @details The event source is broadcasted when an I/O condition happens.
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*
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* @param[in] ip pointer to a @p BaseAsynchronousChannel or derived
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* class
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* @return A pointer to an @p EventSource object.
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*
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* @api
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*/
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#define chIOGetEventSource(ip) (&((ip)->event))
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/**
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* @brief Adds condition flags to the channel's mask.
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* @details This function is usually called from the I/O ISTs in order to
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* notify I/O conditions such as data events, errors, signal
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* changes etc.
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*
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* @param[in] ip pointer to a @p BaseAsynchronousChannel or derived
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* class
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* @param[in] mask condition flags to be added to the mask
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*
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* @iclass
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*/
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#define chIOAddFlagsI(ip, mask) { \
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(ip)->flags |= (mask); \
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chEvtBroadcastI(&(ip)->event); \
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}
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/**
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* @brief Returns and clears the errors mask associated to the channel.
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*
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* @param[in] ip pointer to a @p BaseAsynchronousChannel or derived
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* class
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* @return The condition flags modified since last time this
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* function was invoked.
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*
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* @api
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*/
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#define chIOGetAndClearFlags(ip) ((ip)->vmt->getflags(ip))
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/**
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* @brief Default implementation of the @p getflags virtual method.
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*
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* @param[in] ip pointer to a @p BaseAsynchronousChannel or derived
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* class
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* @return The condition flags modified since last time this
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* function was invoked.
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*
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* @notapi
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*/
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#define _ch_get_and_clear_flags_impl(ip) \
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ioflags_t mask; \
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chSysLock(); \
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mask = ((BaseAsynchronousChannel *)(ip))->flags; \
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((BaseAsynchronousChannel *)(ip))->flags = IO_NO_ERROR; \
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chSysUnlock(); \
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return mask
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#endif /* CH_USE_EVENTS */
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#endif /* _CHIOCH_H_ */
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/** @} */
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