/* ChibiOS/RT - Copyright (C) 2006,2007,2008,2009,2010 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 . */ /** * @file chioch.h * @brief I/O channels. * @details This header defines abstract interfaces useful to access generic * I/O resources in a standardized way. * * @addtogroup io_channels * @details This module defines an abstract interface for I/O channels by * extending the @p BaseSequentialStream interface. 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.
* This system has the advantage to make the access to channels * independent from the implementation logic. * @{ */ #ifndef _CHIOCH_H_ #define _CHIOCH_H_ /** * @brief @p BaseChannel specific methods. */ #define _base_channel_methods \ _base_sequental_stream_methods \ /* Channel output check.*/ \ bool_t (*putwouldblock)(void *instance); \ /* Channel input check.*/ \ bool_t (*getwouldblock)(void *instance); \ /* Channel put method with timeout specification.*/ \ msg_t (*put)(void *instance, uint8_t b, systime_t time); \ /* Channel get method with timeout specification.*/ \ msg_t (*get)(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_sequental_stream_data /** * @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; /** * @brief Channel output check. * @details This function verifies if a subsequent put/write operation would * block. * * @param[in] ip pointer to a @p BaseChannel or derived class * @return The output queue status: * @retval FALSE if the output queue has space and would not block a * write operation. * @retval TRUE if the output queue is full and would block a write * operation. */ #define chIOPutWouldBlock(ip) ((ip)->vmt->putwouldblock(ip)) /** * @brief Channel input check. * @details This function verifies if a subsequent get/read operation would * block. * * @param[in] ip pointer to a @p BaseChannel or derived class * @return The input queue status: * @retval FALSE if the input queue contains data and would not block a * read operation. * @retval TRUE if the input queue is empty and would block a read * operation. */ #define chIOGetWouldBlock(ip) ((ip)->vmt->getwouldblock(ip)) /** * @brief Channel blocking byte write. * @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 * @return The operation status: * @retval Q_OK if the operation succeeded. * @retval Q_RESET if the channel associated queue (if any) was reset. */ #define chIOPut(ip, b) ((ip)->vmt->put(ip, b, TIME_INFINITE)) /** * @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. */ #define chIOPutTimeout(ip, b, time) ((ip)->vmt->put(ip, b, time)) /** * @brief Channel blocking byte read. * @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 * @return A byte value from the queue or: * @retval Q_RESET if the channel associated queue (if any) was reset. */ #define chIOGet(ip) ((ip)->vmt->get(ip, TIME_INFINITE)) /** * @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 or: * @retval Q_TIMEOUT if the specified time expired. * @retval Q_RESET if the channel associated queue (if any) was reset. */ #define chIOGetTimeout(ip, time) ((ip)->vmt->get(ip, time)) /** * @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. */ #define chIOWriteTimeout(ip, bp, n, time) \ ((ip)->vmt->writet(ip, bp, n, time)) /** * @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. */ #define chIOReadTimeout(ip, bp, n, time) \ ((ip)->vmt->readt(ip, bp, n, time)) #if CH_USE_EVENTS /** * @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 \ /* Data Available EventSource.*/ \ EventSource ievent; \ /* Data Transmitted EventSource.*/ \ EventSource oevent; /** * @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; /** * @brief Returns the write event source. * @details The write event source is broadcasted when the channel is ready * for write operations. This usually happens when the internal * output queue becomes empty. * * @param[in] ip pointer to a @p BaseAsynchronousChannel or derived * class * @return A pointer to an @p EventSource object. */ #define chIOGetWriteEventSource(ip) (&((ip)->vmt->oevent)) /** * @brief Returns the read event source. * @details The read event source is broadcasted when the channel is ready * for read operations. This usually happens when the internal * input queue becomes non-empty. * * @param[in] ip pointer to a @p BaseAsynchronousChannel or derived * class * @return A pointer to an @p EventSource object. */ #define chIOGetReadEventSource(ip) (&((ip)->vmt->ievent)) #endif /* CH_USE_EVENTS */ #endif /* _CHIOCH_H_ */ /** @} */ '>262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440