1 files changed, 125 insertions, 0 deletions
diff --git a/os/kernel/src/chmsg.c b/os/kernel/src/chmsg.c
new file mode 100644
index 000000000..393ab8dad
--- /dev/null
+++ b/os/kernel/src/chmsg.c
@@ -0,0 +1,125 @@
+/*
+    ChibiOS/RT - Copyright (C) 2006-2007 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/>.
+*/
+
+/**
+ * @file chmsg.c
+ * @brief Messages code.
+ * @addtogroup Messages
+ * @{
+ */
+
+#include <ch.h>
+
+#if CH_USE_MESSAGES
+
+#if CH_USE_MESSAGES_PRIORITY
+#define msg_insert(tp, qp) prio_insert(tp, qp)
+#else
+#define msg_insert(tp, qp) queue_insert(tp, qp)
+#endif
+
+/**
+ * @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 return message from @p chMsgRelease().
+ */
+msg_t chMsgSend(Thread *tp, msg_t msg) {
+
+  chDbgCheck(tp != NULL, "chMsgSend");
+
+  chSysLock();
+  msg_insert(currp, &tp->p_msgqueue);
+  currp->p_msg = msg;
+  currp->p_wtthdp = tp;
+  if (tp->p_state == PRWTMSG)
+    chSchReadyI(tp);
+  chSchGoSleepS(PRSNDMSG);
+  msg = currp->p_rdymsg;
+  chSysUnlock();
+  return msg;
+}
+
+/**
+ * @brief Suspends the thread and waits for an incoming message.
+ *
+ * @return The pointer to the message structure. Note, it is always the
+ *         message associated to the thread on the top of the messages queue.
+ * @note You can assume that the data contained in the message is stable until
+ *       you invoke @p chMsgRelease() because the sending thread is
+ *       suspended until then.
+ */
+msg_t chMsgWait(void) {
+  msg_t msg;
+
+  chSysLock();
+  if (!chMsgIsPendingI(currp))
+    chSchGoSleepS(PRWTMSG);
+  msg = chMsgGetI(currp);
+  chSysUnlock();
+  return msg;
+}
+
+/**
+ * @brief Returns the next message in the queue.
+ *
+ * @return The pointer to the message structure. Note, it is always the
+ *         message associated to the thread on the top of the messages queue.
+ *         If the queue is empty then @p NULL is returned.
+ * @note 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. Always remember that the message data is not
+ *       copied between the sender and the receiver, just a pointer is passed.
+ */
+msg_t chMsgGet(void) {
+  msg_t msg;
+
+  chSysLock();
+  msg = chMsgIsPendingI(currp) ? chMsgGetI(currp) : (msg_t)NULL;
+  chSysUnlock();
+  return msg;
+}
+
+/**
+ * @brief Releases the thread waiting on top of the messages queue.
+ *
+ * @param[in] msg the message returned to the message sender
+ * @note You can call this function only if there is a message already in the
+ *       queue else the result will be unpredictable (a crash most likely).
+ *       Exiting from the @p chMsgWait() ensures you have at least one
+ *       message in the queue so it is not a big deal.<br>
+ *       The condition is only tested in debug mode in order to make this code
+ *       as fast as possible.
+ */
+void chMsgRelease(msg_t msg) {
+
+  chSysLock();
+  chDbgAssert(chMsgIsPendingI(currp),
+              "chMsgRelease(), #1",
+              "no message pending");
+  chSchWakeupS(fifo_remove(&currp->p_msgqueue), msg);
+  chSysUnlock();
+}
+
+#endif /* CH_USE_MESSAGES */
+
+/** @} */