/*
ChibiOS/RT - Copyright (C) 2006,2007,2008,2009,2010,
2011,2012,2013 Giovanni Di Sirio.
This file is part of ChibiOS/RT.
ChibiOS/RT is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
ChibiOS/RT is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
---
A special exception to the GPL can be applied should you wish to distribute
a combined work that includes ChibiOS/RT, without being obliged to provide
the source code for any proprietary components. See the file exception.txt
for full details of how and when the exception can be applied.
*/
/**
* @file io_channel.h
* @brief I/O channels access.
* @details This header defines an abstract interface useful to access generic
* I/O serial devices in a standardized way.
*
* @addtogroup IO_CHANNEL
* @details This module defines an abstract interface for I/O channels by
* extending the @p BaseSequentialStream interface.<br>
* Note that no code is present, I/O channels are just abstract
* interface like structures, you should look at the systems as
* to a set of abstract C++ classes (even if written in C).
* Specific device drivers can use/extend the interface and
* implement them.<br>
* This system has the advantage to make the access to channels
* independent from the implementation logic.
* @{
*/
#ifndef _IO_CHANNEL_H_
#define _IO_CHANNEL_H_
/**
* @brief @p BaseChannel specific methods.
*/
#define _base_channel_methods \
_base_sequential_stream_methods \
/* Channel put method with timeout specification.*/ \
msg_t (*putt)(void *instance, uint8_t b, systime_t time); \
/* Channel get method with timeout specification.*/ \
msg_t (*gett)(void *instance, systime_t time); \
/* Channel write method with timeout specification.*/ \
size_t (*writet)(void *instance, const uint8_t *bp, \
size_t n, systime_t time); \
/* Channel read method with timeout specification.*/ \
size_t (*readt)(void *instance, uint8_t *bp, size_t n, systime_t time);
/**
* @brief @p BaseChannel specific data.
* @note It is empty because @p BaseChannel is only an interface without
* implementation.
*/
#define _base_channel_data \
_base_sequential_stream_data
/**
* @extends BaseSequentialStreamVMT
*
* @brief @p BaseChannel virtual methods table.
*/
struct BaseChannelVMT {
_base_channel_methods
};
/**
* @extends BaseSequentialStream
*
* @brief Base channel class.
* @details This class represents a generic, byte-wide, I/O channel. This class
* introduces generic I/O primitives with timeout specification.
*/
typedef struct {
/** @brief Virtual Methods Table.*/
const struct BaseChannelVMT *vmt;
_base_channel_data
} BaseChannel;
/**
* @name Macro Functions (BaseChannel)
* @{
*/
/**
* @brief Channel blocking byte write with timeout.
* @details This function writes a byte value to a channel. If the channel
* is not ready to accept data then the calling thread is suspended.
*
* @param[in] ip pointer to a @p BaseChannel or derived class
* @param[in] b the byte value to be written to the channel
* @param[in] time the number of ticks before the operation timeouts,
* the following special values are allowed:
* - @a TIME_IMMEDIATE immediate timeout.
* - @a TIME_INFINITE no timeout.
* .
* @return The operation status.
* @retval Q_OK if the operation succeeded.
* @retval Q_TIMEOUT if the specified time expired.
* @retval Q_RESET if the channel associated queue (if any) was reset.
*
* @api
*/
#define chnPutTimeout(ip, b, time) ((ip)->vmt->putt(ip, b, time))
/**
* @brief Channel blocking byte read with timeout.
* @details This function reads a byte value from a channel. If the data
* is not available then the calling thread is suspended.
*
* @param[in] ip pointer to a @p BaseChannel or derived class
* @param[in] time the number of ticks before the operation timeouts,
* the following special values are allowed:
* - @a TIME_IMMEDIATE immediate timeout.
* - @a TIME_INFINITE no timeout.
* .
* @return A byte value from the queue.
* @retval Q_TIMEOUT if the specified time expired.
* @retval Q_RESET if the channel associated queue (if any) has been
* reset.
*
* @api
*/
#define chnGetTimeout(ip, time) ((ip)->vmt->gett(ip, time))
/**
* @brief Channel blocking write.
* @details The function writes data from a buffer to a channel. If the channel
* is not ready to accept data then the calling thread is suspended.
*
* @param[in] ip pointer to a @p BaseChannel or derived class
* @param[out] bp pointer to the data buffer
* @param[in] n the maximum amount of data to be transferred
*
* @return The number of bytes transferred.
*
* @api
*/
#define chnWrite(ip, bp, n) chSequentialStreamWrite(ip, bp, n)
/**
* @brief Channel blocking write with timeout.
* @details The function writes data from a buffer to a channel. If the channel
* is not ready to accept data then the calling thread is suspended.
*
* @param[in] ip pointer to a @p BaseChannel or derived class
* @param[out] bp pointer to the data buffer
* @param[in] n the maximum amount of data to be transferred
* @param[in] time the number of ticks before the operation timeouts,
* the following special values are allowed:
* - @a TIME_IMMEDIATE immediate timeout.
* - @a TIME_INFINITE no timeout.
* .
* @return The number of bytes transferred.
*
* @api
*/
#define chnWriteTimeout(ip, bp, n, time) ((ip)->vmt->writet(ip, bp, n, time))
/**
* @brief Channel blocking read.
* @details The function reads data from a channel into a buffer. If the data
* is not available then the calling thread is suspended.
*
* @param[in] ip pointer to a @p BaseChannel or derived class
* @param[in] bp pointer to the data buffer
* @param[in] n the maximum amount of data to be transferred
*
* @return The number of bytes transferred.
*
* @api
*/
#define chnRead(ip, bp, n) chSequentialStreamRead(ip, bp, n)
/**
* @brief Channel blocking read with timeout.
* @details The function reads data from a channel into a buffer. If the data
* is not available then the calling thread is suspended.
*
* @param[in] ip pointer to a @p BaseChannel or derived class
* @param[in] bp pointer to the data buffer
* @param[in] n the maximum amount of data to be transferred
* @param[in] time the number of ticks before the operation timeouts,
* the following special values are allowed:
* - @a TIME_IMMEDIATE immediate timeout.
* - @a TIME_INFINITE no timeout.
* .
* @return The number of bytes transferred.
*
* @api
*/
#define chnReadTimeout(ip, bp, n, time) ((ip)->vmt->readt(ip, bp, n, time))
/** @} */
#if CH_USE_EVENTS || defined(__DOXYGEN__)
/**
* @name I/O status flags added to the event listener
* @{
*/
/** @brief No pending conditions.*/
#define CHN_NO_ERROR 0
/** @brief Connection happened.*/
#define CHN_CONNECTED 1
/** @brief Disconnection happened.*/
#define CHN_DISCONNECTED 2
/** @brief Data available in the input queue.*/
#define CHN_INPUT_AVAILABLE 4
/** @brief Output queue empty.*/
#define CHN_OUTPUT_EMPTY 8
/** @brief Transmission end.*/
#define CHN_TRANSMISSION_END 16
/** @} */
/**
* @brief @p BaseAsynchronousChannel specific methods.
*/
#define _base_asynchronous_channel_methods \
_base_channel_methods \
/**
* @brief @p BaseAsynchronousChannel specific data.
*/
#define _base_asynchronous_channel_data \
_base_channel_data \
/* I/O condition event source.*/ \
EventSource event;
/**
* @extends BaseChannelVMT
*
* @brief @p BaseAsynchronousChannel virtual methods table.
*/
struct BaseAsynchronousChannelVMT {
_base_asynchronous_channel_methods
};
/**
* @extends BaseChannel
*
* @brief Base asynchronous channel class.
* @details This class extends @p BaseChannel by adding event sources fields
* for asynchronous I/O for use in an event-driven environment.
*/
typedef struct {
/** @brief Virtual Methods Table.*/
const struct BaseAsynchronousChannelVMT *vmt;
_base_asynchronous_channel_data
} BaseAsynchronousChannel;
/**
* @name Macro Functions (BaseAsynchronousChannel)
* @{
*/
/**
* @brief Returns the I/O condition event source.
* @details The event source is broadcasted when an I/O condition happens.
*
* @param[in] ip pointer to a @p BaseAsynchronousChannel or derived
* class
* @return A pointer to an @p EventSource object.
*
* @api
*/
#define chnGetEventSource(ip) (&((ip)->event))
/**
* @brief Adds status flags to the listeners's flags mask.
* @details This function is usually called from the I/O ISRs in order to
* notify I/O conditions such as data events, errors, signal
* changes etc.
*
* @param[in] ip pointer to a @p BaseAsynchronousChannel or derived
* class
* @param[in] flags condition flags to be added to the listener flags mask
*
* @iclass
*/
#define chnAddFlagsI(ip, flags) { \
chEvtBroadcastFlagsI(&(ip)->event, flags); \
}
/** @} */
#endif /* CH_USE_EVENTS */
#endif /* _IO_CHANNEL_H_ */
/** @} */