diff options
Diffstat (limited to 'ChibiOS_20.3.2/os/rt/src/chmsg.c')
| -rw-r--r-- | ChibiOS_20.3.2/os/rt/src/chmsg.c | 221 |
1 files changed, 221 insertions, 0 deletions
diff --git a/ChibiOS_20.3.2/os/rt/src/chmsg.c b/ChibiOS_20.3.2/os/rt/src/chmsg.c new file mode 100644 index 0000000..2003dd0 --- /dev/null +++ b/ChibiOS_20.3.2/os/rt/src/chmsg.c @@ -0,0 +1,221 @@ +/*
+ ChibiOS - Copyright (C) 2006..2018 Giovanni Di Sirio.
+
+ This file is part of ChibiOS.
+
+ ChibiOS 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 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/>.
+*/
+
+/**
+ * @file rt/src/chmsg.c
+ * @brief Messages code.
+ *
+ * @addtogroup messages
+ * @details Synchronous inter-thread messages APIs and services.
+ * <h2>Operation Mode</h2>
+ * Synchronous messages are an easy to use and fast IPC mechanism,
+ * threads can both act as message servers and/or message clients,
+ * the mechanism allows data to be carried in both directions. Note
+ * that messages are not copied between the client and server threads
+ * but just a pointer passed so the exchange is very time
+ * efficient.<br>
+ * Messages are scalar data types of type @p msg_t that are guaranteed
+ * to be size compatible with data pointers. Note that on some
+ * architectures function pointers can be larger that @p msg_t.<br>
+ * Messages are usually processed in FIFO order but it is possible to
+ * process them in priority order by enabling the
+ * @p CH_CFG_USE_MESSAGES_PRIORITY option in @p chconf.h.<br>
+ * @pre In order to use the message APIs the @p CH_CFG_USE_MESSAGES option
+ * must be enabled in @p chconf.h.
+ * @post Enabling messages requires 6-12 (depending on the architecture)
+ * extra bytes in the @p thread_t structure.
+ * @{
+ */
+
+#include "ch.h"
+
+#if (CH_CFG_USE_MESSAGES == TRUE) || defined(__DOXYGEN__)
+
+/*===========================================================================*/
+/* Module exported variables. */
+/*===========================================================================*/
+
+/*===========================================================================*/
+/* Module local types. */
+/*===========================================================================*/
+
+/*===========================================================================*/
+/* Module local variables. */
+/*===========================================================================*/
+
+/*===========================================================================*/
+/* Module local functions. */
+/*===========================================================================*/
+
+#if CH_CFG_USE_MESSAGES_PRIORITY == TRUE
+#define msg_insert(tp, qp) queue_prio_insert(tp, qp)
+#else
+#define msg_insert(tp, qp) queue_insert(tp, qp)
+#endif
+
+/*===========================================================================*/
+/* Module exported functions. */
+/*===========================================================================*/
+
+/**
+ * @brief Sends a message to the specified thread.
+ * @details The sender is stopped until the receiver executes a
+ * @p chMsgRelease()after receiving the message.
+ *
+ * @param[in] tp the pointer to the thread
+ * @param[in] msg the message
+ * @return The answer message from @p chMsgRelease().
+ *
+ * @api
+ */
+msg_t chMsgSend(thread_t *tp, msg_t msg) {
+ thread_t *ctp = currp;
+
+ chDbgCheck(tp != NULL);
+
+ chSysLock();
+ ctp->u.sentmsg = msg;
+ msg_insert(ctp, &tp->msgqueue);
+ if (tp->state == CH_STATE_WTMSG) {
+ (void) chSchReadyI(tp);
+ }
+ chSchGoSleepS(CH_STATE_SNDMSGQ);
+ msg = ctp->u.rdymsg;
+ chSysUnlock();
+
+ return msg;
+}
+
+/**
+ * @brief Suspends the thread and waits for an incoming message.
+ * @post After receiving a message the function @p chMsgGet() must be
+ * called in order to retrieve the message and then @p chMsgRelease()
+ * must be invoked in order to acknowledge the reception and send
+ * the answer.
+ * @note If the message is a pointer then you can assume that the data
+ * pointed by the message is stable until you invoke @p chMsgRelease()
+ * because the sending thread is suspended until then.
+ * @note The reference counter of the sender thread is not increased, the
+ * returned pointer is a temporary reference.
+ *
+ * @return A pointer to the thread carrying the message.
+ *
+ * @sclass
+ */
+thread_t *chMsgWaitS(void) {
+ thread_t *tp;
+
+ chDbgCheckClassS();
+
+ if (!chMsgIsPendingI(currp)) {
+ chSchGoSleepS(CH_STATE_WTMSG);
+ }
+ tp = queue_fifo_remove(&currp->msgqueue);
+ tp->state = CH_STATE_SNDMSG;
+
+ return tp;
+}
+
+/**
+ * @brief Suspends the thread and waits for an incoming message or a
+ * timeout to occur.
+ * @post After receiving a message the function @p chMsgGet() must be
+ * called in order to retrieve the message and then @p chMsgRelease()
+ * must be invoked in order to acknowledge the reception and send
+ * the answer.
+ * @note If the message is a pointer then you can assume that the data
+ * pointed by the message is stable until you invoke @p chMsgRelease()
+ * because the sending thread is suspended until then.
+ * @note The reference counter of the sender thread is not increased, the
+ * returned pointer is a temporary reference.
+ *
+ * @param[in] timeout the number of ticks before the operation timeouts,
+ * the following special values are allowed:
+ * - @a TIME_INFINITE no timeout.
+ * .
+ * @return A pointer to the thread carrying the message.
+ * @retval NULL if a timeout occurred.
+ *
+ * @sclass
+ */
+thread_t *chMsgWaitTimeoutS(sysinterval_t timeout) {
+ thread_t *tp;
+
+ chDbgCheckClassS();
+
+ if (!chMsgIsPendingI(currp)) {
+ if (chSchGoSleepTimeoutS(CH_STATE_WTMSG, timeout) != MSG_OK) {
+ return NULL;
+ }
+ }
+ tp = queue_fifo_remove(&currp->msgqueue);
+ tp->state = CH_STATE_SNDMSG;
+
+ return tp;
+}
+
+/**
+ * @brief Poll to check for an incoming message.
+ * @post If a message is available the function @p chMsgGet() must be
+ * called in order to retrieve the message and then @p chMsgRelease()
+ * must be invoked in order to acknowledge the reception and send
+ * the answer.
+ * @note If the message is a pointer then you can assume that the data
+ * pointed by the message is stable until you invoke @p chMsgRelease()
+ * because the sending thread is suspended until then.
+ * @note The reference counter of the sender thread is not increased, the
+ * returned pointer is a temporary reference.
+ *
+ * @return Result of the poll.
+ * @retval NULL if no incoming message waiting.
+ *
+ * @sclass
+ */
+thread_t *chMsgPollS(void) {
+ thread_t *tp = NULL;
+
+ if (chMsgIsPendingI(currp)) {
+ tp = queue_fifo_remove(&currp->msgqueue);
+ tp->state = CH_STATE_SNDMSG;
+ }
+
+ return tp;
+}
+
+/**
+ * @brief Releases a sender thread specifying a response message.
+ * @pre Invoke this function only after a message has been received
+ * using @p chMsgWait().
+ *
+ * @param[in] tp pointer to the thread
+ * @param[in] msg message to be returned to the sender
+ *
+ * @api
+ */
+void chMsgRelease(thread_t *tp, msg_t msg) {
+
+ chSysLock();
+ chDbgAssert(tp->state == CH_STATE_SNDMSG, "invalid state");
+ chMsgReleaseS(tp, msg);
+ chSysUnlock();
+}
+
+#endif /* CH_CFG_USE_MESSAGES == TRUE */
+
+/** @} */
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