diff options
Diffstat (limited to 'os/nil/src/nil.c')
| -rw-r--r-- | os/nil/src/nil.c | 598 |
1 files changed, 598 insertions, 0 deletions
diff --git a/os/nil/src/nil.c b/os/nil/src/nil.c new file mode 100644 index 000000000..da75ce1a9 --- /dev/null +++ b/os/nil/src/nil.c @@ -0,0 +1,598 @@ +/*
+ Nil RTOS - Copyright (C) 2012 Giovanni Di Sirio.
+
+ This file is part of Nil RTOS.
+
+ Nil RTOS 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.
+
+ Nil RTOS 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 nil.c
+ * @brief Nil RTOS main source file.
+ *
+ * @defgroup nil
+ * @details Nil RTOS services.
+ * @{
+ */
+
+#include "nil.h"
+
+/*===========================================================================*/
+/* Module local definitions. */
+/*===========================================================================*/
+
+/*===========================================================================*/
+/* Module exported variables. */
+/*===========================================================================*/
+
+/**
+ * @brief System data structures.
+ */
+nil_system_t nil;
+
+/*===========================================================================*/
+/* Module local variables. */
+/*===========================================================================*/
+
+/*===========================================================================*/
+/* Module local functions. */
+/*===========================================================================*/
+
+/*===========================================================================*/
+/* Module interrupt handlers. */
+/*===========================================================================*/
+
+/*===========================================================================*/
+/* Module exported functions. */
+/*===========================================================================*/
+
+/**
+ * @brief Initializes the kernel.
+ * @details Initializes the kernel structures, the current instructions flow
+ * becomes the idle thread upon return. The idle thread must not
+ * invoke any kernel primitive able to change state to not runnable.
+ *
+ * @special
+ */
+void nilSysInit(void) {
+ thread_ref_t tr;
+ const thread_config_t *tcp;
+
+ /* Port layer initialization.*/
+ port_init();
+
+ /* Iterates through the list of defined threads.*/
+ for (tr = &nil.threads[0], tcp = nil_thd_configs;
+ tr < &nil.threads[NIL_CFG_NUM_THREADS];
+ tr++, tcp++) {
+ tr->state = NIL_THD_READY;
+ tr->timeout = 0;
+
+ /* Port dependent thread initialization.*/
+ SETUP_CONTEXT(tr, tcp->wap, tcp->size, tcp->funcp, tcp->arg);
+
+ /* Initialization hook.*/
+#if defined(NIL_CFG_THREAD_EXT_INIT_HOOK)
+ NIL_CFG_THREAD_EXT_INIT_HOOK(tr);
+#endif
+ }
+
+ /* Runs the highest priority thread, the current one becomes the null
+ thread.*/
+ nil.current = nil.next = nil.threads;
+ port_switch(nil.threads, &nil.threads[NIL_CFG_NUM_THREADS]);
+
+ /* Interrupts enabled for the idle thread.*/
+ nilSysEnable();
+}
+
+/**
+ * @brief Time management handler.
+ * @note This handler has to be invoked by a periodic ISR in order to
+ * reschedule the waiting threads.
+ *
+ * @iclass
+ */
+void nilSysTimerHandlerI(void) {
+
+#if NIL_CFG_TIMEDELTA == 0
+ thread_ref_t tr = &nil.threads[0];
+ nil.systime++;
+ do {
+ /* Is the thread in a wait state with timeout?.*/
+ if (tr->timeout > 0) {
+
+ nilDbgAssert(!NIL_THD_IS_READY(tr),
+ "nilSysTimerHandlerI(), #1", "is ready");
+
+ /* Did the timer reach zero?*/
+ if (--tr->timeout == 0) {
+ /* Timeout on semaphores requires a special handling because the
+ semaphore counter must be incremented.*/
+ if (NIL_THD_IS_WTSEM(tr))
+ tr->u1.semp->cnt++;
+ else if (NIL_THD_IS_SUSP(tr))
+ tr->u1.trp = NULL;
+ nilSchReadyI(tr, NIL_MSG_TMO);
+ }
+ }
+ /* Lock released in order to give a preemption chance on those
+ architectures supporting IRQ preemption.*/
+ nilSysUnlockFromISR();
+ tr++;
+ nilSysLockFromISR();
+ } while (tr < &nil.threads[NIL_CFG_NUM_THREADS]);
+#else
+ thread_ref_t tr = &nil.threads[0];
+ systime_t next = 0;
+
+ nilDbgAssert(nil.nexttime == port_timer_get_alarm(),
+ "nilSysTimerHandlerI(), #1", "time mismatch");
+
+ do {
+ /* Is the thread in a wait state with timeout?.*/
+ if (tr->timeout > 0) {
+
+ nilDbgAssert(!NIL_THD_IS_READY(tr),
+ "nilSysTimerHandlerI(), #2", "is ready");
+ nilDbgAssert(tr->timeout >= nil.nexttime - nil.lasttime,
+ "nilSysTimerHandlerI(), #3", "skipped one");
+
+ tr->timeout -= nil.nexttime - nil.lasttime;
+ if (tr->timeout == 0) {
+ /* Timeout on semaphores requires a special handling because the
+ semaphore counter must be incremented.*/
+ if (NIL_THD_IS_WTSEM(tr))
+ tr->u1.semp->cnt++;
+ else if (NIL_THD_IS_SUSP(tr))
+ tr->u1.trp = NULL;
+ nilSchReadyI(tr, NIL_MSG_TMO);
+ }
+ else {
+ if (tr->timeout <= next - 1)
+ next = tr->timeout;
+ }
+ }
+ /* Lock released in order to give a preemption chance on those
+ architectures supporting IRQ preemption.*/
+ nilSysUnlockFromISR();
+ tr++;
+ nilSysLockFromISR();
+ } while (tr < &nil.threads[NIL_CFG_NUM_THREADS]);
+ nil.lasttime = nil.nexttime;
+ if (next > 0) {
+ nil.nexttime += next;
+ port_timer_set_alarm(nil.nexttime);
+ }
+ else {
+ /* No tick event needed.*/
+ port_timer_stop_alarm();
+ }
+#endif
+}
+
+/**
+ * @brief Makes the specified thread ready for execution.
+ *
+ * @param[in] tr reference to the @p thread_t object
+ * @param[in] msg the wakeup message
+ *
+ * @return The same reference passed as parameter.
+ */
+thread_ref_t nilSchReadyI(thread_ref_t tr, msg_t msg) {
+
+ nilDbgAssert((tr >= nil.threads) &&
+ (tr < &nil.threads[NIL_CFG_NUM_THREADS]),
+ "nilSchReadyI(), #1", "pointer out of range");
+ nilDbgAssert(!NIL_THD_IS_READY(tr),
+ "nilSchReadyI(), #2", "already ready");
+ nilDbgAssert(nil.next <= nil.current,
+ "nilSchReadyI(), #3", "priority ordering");
+
+ tr->u1.msg = msg;
+ tr->state = NIL_THD_READY;
+ tr->timeout = 0;
+ if (tr < nil.next)
+ nil.next = tr;
+ return tr;
+}
+
+/**
+ * @brief Reschedules.
+ *
+ * @sclass
+ */
+void nilSchRescheduleS() {
+ thread_ref_t otr = nil.current;
+ thread_ref_t ntr = nil.next;
+
+ if (ntr != otr) {
+ nil.current = ntr;
+#if defined(NIL_CFG_IDLE_LEAVE_HOOK)
+ if (otr == &nil.threads[NIL_CFG_NUM_THREADS]) {
+ NIL_CFG_IDLE_LEAVE_HOOK();
+ }
+#endif
+ port_switch(ntr, otr);
+ }
+}
+
+/**
+ * @brief Puts the current thread to sleep into the specified state with
+ * timeout specification.
+ * @details The thread goes into a sleeping state, if it is not awakened
+ * explicitly within the specified system time then it is forcibly
+ * awakened with a @p NIL_MSG_TMO low level message.
+ *
+ * @param[in] newstate the new thread state or a semaphore pointer
+ * @param[in] timeout the number of ticks before the operation timeouts.
+ * the following special values are allowed:
+ * - @a TIME_INFINITE no timeout.
+ * .
+ * @return The wakeup message.
+ * @retval NIL_MSG_TMO if a timeout occurred.
+ *
+ * @sclass
+ */
+msg_t nilSchGoSleepTimeoutS(tstate_t newstate, systime_t timeout) {
+ thread_ref_t ntr, otr = nil.current;
+
+ nilDbgAssert(otr != &nil.threads[NIL_CFG_NUM_THREADS],
+ "nilSchGoSleepTimeoutS(), #1", "idle cannot sleep");
+
+ /* Storing the wait object for the current thread.*/
+ otr->state = newstate;
+
+#if NIL_CFG_TIMEDELTA > 0
+ if (timeout != TIME_INFINITE) {
+ systime_t time = nilTimeNowI() + timeout;
+
+ /* TIMEDELTA makes sure to have enough time to reprogram the timer
+ before the free-running timer counter reaches the selected timeout.*/
+ if (timeout < NIL_CFG_TIMEDELTA)
+ timeout = NIL_CFG_TIMEDELTA;
+
+ if (nil.lasttime == nil.nexttime) {
+ /* Special case, first thread asking for a timeout.*/
+ port_timer_start_alarm(time);
+ nil.nexttime = time;
+ }
+ else {
+ /* Special case, there are already other threads with a timeout
+ activated, evaluating the order.*/
+ if (nilTimeIsWithin(time, nil.lasttime, nil.nexttime)) {
+ port_timer_set_alarm(time);
+ nil.nexttime = time;
+ }
+ }
+
+ /* Timeout settings.*/
+ otr->timeout = time - nil.lasttime;
+ }
+#else
+
+ /* Timeout settings.*/
+ otr->timeout = timeout;
+#endif
+
+ /* Scanning the whole threads array.*/
+ ntr = nil.threads;
+ while (true) {
+ /* Is this thread ready to execute?*/
+ if (NIL_THD_IS_READY(ntr)) {
+ nil.current = nil.next = ntr;
+#if defined(NIL_CFG_IDLE_ENTER_HOOK)
+ if (ntr == &nil.threads[NIL_CFG_NUM_THREADS]) {
+ NIL_CFG_IDLE_ENTER_HOOK();
+ }
+#endif
+ port_switch(ntr, otr);
+ return nil.current->u1.msg;
+ }
+
+ /* Points to the next thread in lowering priority order.*/
+ ntr++;
+ nilDbgAssert(ntr <= &nil.threads[NIL_CFG_NUM_THREADS],
+ "nilSchGoSleepTimeoutS(), #2", "pointer out of range");
+ }
+}
+
+/**
+ * @brief Sends the current thread sleeping and sets a reference variable.
+ * @note This function must reschedule, it can only be called from thread
+ * context.
+ *
+ * @param[in] trp a pointer to a thread reference object
+ * @param[in] timeout the number of ticks before the operation timeouts,
+ * the following special values are allowed:
+ * - @a TIME_INFINITE no timeout.
+ * .
+ * @return The wake up message.
+ *
+ * @sclass
+ */
+msg_t nilThdSuspendTimeoutS(thread_ref_t *trp, systime_t timeout) {
+
+ nilDbgAssert(*trp == NULL, "nilThdSuspendTimeoutS(), #1", "not NULL");
+
+ *trp = nil.current;
+ nil.current->u1.trp = trp;
+ return nilSchGoSleepTimeoutS(NIL_THD_SUSP, timeout);
+}
+
+/**
+ * @brief Wakes up a thread waiting on a thread reference object.
+ * @note This function must not reschedule because it can be called from
+ * ISR context.
+ *
+ * @param[in] trp a pointer to a thread reference object
+ * @param[in] msg the message code
+ *
+ * @iclass
+ */
+void nilThdResumeI(thread_ref_t *trp, msg_t msg) {
+
+ if (*trp != NULL) {
+ thread_ref_t tr = *trp;
+
+ nilDbgAssert(NIL_THD_IS_SUSP(tr), "nilThdResumeI(), #1", "not suspended");
+
+ *trp = NULL;
+ nilSchReadyI(tr, msg);
+ }
+}
+
+/**
+ * @brief Suspends the invoking thread for the specified time.
+ *
+ * @param[in] time the delay in system ticks
+ *
+ * @api
+ */
+void nilThdSleep(systime_t time) {
+
+ nilSysLock();
+ nilThdSleepS(time);
+ nilSysUnlock();
+}
+
+/**
+ * @brief Suspends the invoking thread until the system time arrives to the
+ * specified value.
+ *
+ * @param[in] time absolute system time
+ *
+ * @api
+ */
+void nilThdSleepUntil(systime_t time) {
+
+ nilSysLock();
+ nilThdSleepUntilS(time);
+ nilSysUnlock();
+}
+
+/**
+ * @brief Current system time.
+ * @details Returns the number of system ticks since the @p nilSysInit()
+ * invocation.
+ * @note The counter can reach its maximum and then restart from zero.
+ * @note This function is designed to work with the @p nilThdSleepUntil().
+ *
+ * @return The system time in ticks.
+ *
+ * @api
+ */
+systime_t nilTimeNow(void) {
+ systime_t time;
+
+ nilSysLock();
+ time = nilTimeNowI();
+ nilSysUnlock();
+ return time;
+}
+
+/**
+ * @brief Checks if the current system time is within the specified time
+ * window.
+ * @note When start==end then the function returns always true because the
+ * whole time range is specified.
+ *
+ * @param[in] start the start of the time window (inclusive)
+ * @param[in] end the end of the time window (non inclusive)
+ *
+ * @retval true current time within the specified time window.
+ * @retval false current time not within the specified time window.
+ *
+ * @api
+ */
+bool nilTimeNowIsWithin(systime_t start, systime_t end) {
+
+ systime_t time = nilTimeNow();
+ return nilTimeIsWithin(time, start, end);
+}
+
+/**
+ * @brief Performs a wait operation on a semaphore with timeout specification.
+ *
+ * @param[in] sp pointer to a @p semaphore_t structure
+ * @param[in] timeout 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 message specifying how the invoking thread has been
+ * released from the semaphore.
+ * @retval NIL_MSG_OK if the thread has not stopped on the semaphore or the
+ * semaphore has been signaled.
+ * @retval NIL_MSG_RST if the semaphore has been reset using @p nilSemReset().
+ * @retval NIL_MSG_TMO if the semaphore has not been signaled or reset within
+ * the specified timeout.
+ *
+ * @api
+ */
+msg_t nilSemWaitTimeout(semaphore_t *sp, systime_t timeout) {
+ msg_t msg;
+
+ nilSysLock();
+ msg = nilSemWaitTimeoutS(sp, timeout);
+ nilSysUnlock();
+ return msg;
+}
+
+/**
+ * @brief Performs a wait operation on a semaphore with timeout specification.
+ *
+ * @param[in] sp pointer to a @p semaphore_t structure
+ * @param[in] timeout 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 message specifying how the invoking thread has been
+ * released from the semaphore.
+ * @retval NIL_MSG_OK if the thread has not stopped on the semaphore or the
+ * semaphore has been signaled.
+ * @retval NIL_MSG_RST if the semaphore has been reset using @p nilSemReset().
+ * @retval NIL_MSG_TMO if the semaphore has not been signaled or reset within
+ * the specified timeout.
+ *
+ * @sclass
+ */
+msg_t nilSemWaitTimeoutS(semaphore_t *sp, systime_t timeout) {
+
+ /* Note, the semaphore counter is a volatile variable so accesses are
+ manually optimized.*/
+ cnt_t cnt = sp->cnt;
+ if (cnt <= 0) {
+ if (TIME_IMMEDIATE == timeout)
+ return NIL_MSG_TMO;
+ sp->cnt = cnt - 1;
+ nil.current->u1.semp = sp;
+ return nilSchGoSleepTimeoutS(NIL_THD_WTSEM, timeout);
+ }
+ sp->cnt = cnt - 1;
+ return NIL_MSG_OK;
+}
+
+/**
+ * @brief Performs a signal operation on a semaphore.
+ * @post This function does not reschedule so a call to a rescheduling
+ * function must be performed before unlocking the kernel. Note that
+ * interrupt handlers always reschedule on exit so an explicit
+ * reschedule must not be performed in ISRs.
+ *
+ * @param[in] sp pointer to a @p semaphore_t structure
+ *
+ * @api
+ */
+void nilSemSignal(semaphore_t *sp) {
+
+ nilSysLock();
+ nilSemSignalI(sp);
+ nilSchRescheduleS();
+ nilSysUnlock();
+}
+
+/**
+ * @brief Performs a signal operation on a semaphore.
+ * @post This function does not reschedule so a call to a rescheduling
+ * function must be performed before unlocking the kernel. Note that
+ * interrupt handlers always reschedule on exit so an explicit
+ * reschedule must not be performed in ISRs.
+ *
+ * @param[in] sp pointer to a @p semaphore_t structure
+ *
+ * @iclass
+ */
+void nilSemSignalI(semaphore_t *sp) {
+
+ if (++sp->cnt <= 0) {
+ thread_ref_t tr = nil.threads;
+ while (true) {
+ /* Is this thread waiting on this semaphore?*/
+ if (tr->u1.semp == sp) {
+
+ nilDbgAssert(NIL_THD_IS_WTSEM(tr),
+ "nilSemSignalI(), #1", "not waiting");
+
+ nilSchReadyI(tr, NIL_MSG_OK);
+ return;
+ }
+ tr++;
+ }
+ }
+}
+
+/**
+ * @brief Performs a reset operation on the semaphore.
+ * @post After invoking this function all the threads waiting on the
+ * semaphore, if any, are released and the semaphore counter is set
+ * to the specified, non negative, value.
+ * @post This function does not reschedule so a call to a rescheduling
+ * function must be performed before unlocking the kernel. Note that
+ * interrupt handlers always reschedule on exit so an explicit
+ * reschedule must not be performed in ISRs.
+ *
+ * @param[in] sp pointer to a @p semaphore_t structure
+ * @param[in] n the new value of the semaphore counter. The value must
+ * be non-negative.
+ *
+ * @api
+ */
+void nilSemReset(semaphore_t *sp, cnt_t n) {
+
+ nilSysLock();
+ nilSemResetI(sp, n);
+ nilSchRescheduleS();
+ nilSysUnlock();
+}
+
+/**
+ * @brief Performs a reset operation on the semaphore.
+ * @post After invoking this function all the threads waiting on the
+ * semaphore, if any, are released and the semaphore counter is set
+ * to the specified, non negative, value.
+ * @post This function does not reschedule so a call to a rescheduling
+ * function must be performed before unlocking the kernel. Note that
+ * interrupt handlers always reschedule on exit so an explicit
+ * reschedule must not be performed in ISRs.
+ *
+ * @param[in] sp pointer to a @p semaphore_t structure
+ * @param[in] n the new value of the semaphore counter. The value must
+ * be non-negative.
+ *
+ * @iclass
+ */
+void nilSemResetI(semaphore_t *sp, cnt_t n) {
+ thread_ref_t tr;
+ cnt_t cnt;
+
+ cnt = sp->cnt;
+ sp->cnt = n;
+ tr = nil.threads;
+ while (cnt < 0) {
+ /* Is this thread waiting on this semaphore?*/
+ if (tr->u1.semp == sp) {
+
+ nilDbgAssert(NIL_THD_IS_WTSEM(tr),
+ "nilSemResetI(), #1", "not waiting");
+
+ cnt++;
+ nilSchReadyI(tr, NIL_MSG_RST);
+ }
+ tr++;
+ }
+}
+
+/** @} */
|