tinySA/os/nil/src/nil.c

794 lines
24 KiB
C

/*
ChibiOS - Copyright (C) 2006..2015 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 nil.c
* @brief Nil RTOS main source file.
*
* @addtogroup NIL_KERNEL
* @{
*/
#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.
* @note This function assumes that the @p nil global variable has been
* zeroed by the runtime environment. If this is not the case then
* make sure to clear it before calling this function.
*
* @special
*/
void chSysInit(void) {
thread_t *tp;
const thread_config_t *tcp;
/* Port layer initialization.*/
port_init();
/* System initialization hook.*/
NIL_CFG_SYSTEM_INIT_HOOK();
/* Iterates through the list of defined threads.*/
tp = &nil.threads[0];
tcp = nil_thd_configs;
while (tp < &nil.threads[NIL_CFG_NUM_THREADS]) {
#if NIL_CFG_ENABLE_STACK_CHECK
tp->stklim = (stkalign_t *)tcp->wbase;
#endif
/* Port dependent thread initialization.*/
PORT_SETUP_CONTEXT(tp, tcp->wend, tcp->funcp, tcp->arg);
/* Initialization hook.*/
NIL_CFG_THREAD_EXT_INIT_HOOK(tp);
tp++;
tcp++;
}
#if NIL_CFG_ENABLE_STACK_CHECK
/* The idle thread is a special case because its stack is set up by the
runtime environment.*/
tp->stklim = THD_IDLE_BASE;
#endif
/* Runs the highest priority thread, the current one becomes the null
thread.*/
nil.current = nil.next = nil.threads;
port_switch(nil.current, tp);
/* Interrupts enabled for the idle thread.*/
chSysEnable();
}
/**
* @brief Halts the system.
* @details This function is invoked by the operating system when an
* unrecoverable error is detected, for example because a programming
* error in the application code that triggers an assertion while
* in debug mode.
* @note Can be invoked from any system state.
*
* @param[in] reason pointer to an error string
*
* @special
*/
void chSysHalt(const char *reason) {
port_disable();
#if NIL_DBG_ENABLED
nil.dbg_panic_msg = reason;
#else
(void)reason;
#endif
NIL_CFG_SYSTEM_HALT_HOOK(reason);
/* Harmless infinite loop.*/
while (true) {
}
}
/**
* @brief Time management handler.
* @note This handler has to be invoked by a periodic ISR in order to
* reschedule the waiting threads.
*
* @iclass
*/
void chSysTimerHandlerI(void) {
#if NIL_CFG_ST_TIMEDELTA == 0
thread_t *tp = &nil.threads[0];
nil.systime++;
do {
/* Is the thread in a wait state with timeout?.*/
if (tp->timeout > (systime_t)0) {
chDbgAssert(!NIL_THD_IS_READY(tp), "is ready");
/* Did the timer reach zero?*/
if (--tp->timeout == (systime_t)0) {
/* Timeout on semaphores requires a special handling because the
semaphore counter must be incremented.*/
/*lint -save -e9013 [15.7] There is no else because it is not needed.*/
if (NIL_THD_IS_WTSEM(tp)) {
tp->u1.semp->cnt++;
}
else if (NIL_THD_IS_SUSP(tp)) {
*tp->u1.trp = NULL;
}
/*lint -restore*/
(void) chSchReadyI(tp, MSG_TIMEOUT);
}
}
/* Lock released in order to give a preemption chance on those
architectures supporting IRQ preemption.*/
chSysUnlockFromISR();
tp++;
chSysLockFromISR();
} while (tp < &nil.threads[NIL_CFG_NUM_THREADS]);
#else
thread_t *tp = &nil.threads[0];
systime_t next = (systime_t)0;
chDbgAssert(nil.nexttime == port_timer_get_alarm(), "time mismatch");
do {
/* Is the thread in a wait state with timeout?.*/
if (tp->timeout > (systime_t)0) {
chDbgAssert(!NIL_THD_IS_READY(tp), "is ready");
chDbgAssert(tp->timeout >= (nil.nexttime - nil.lasttime), "skipped one");
tp->timeout -= nil.nexttime - nil.lasttime;
if (tp->timeout == (systime_t)0) {
/* Timeout on semaphores requires a special handling because the
semaphore counter must be incremented.*/
/*lint -save -e9013 [15.7] There is no else because it is not needed.*/
if (NIL_THD_IS_WTSEM(tp)) {
tp->u1.semp->cnt++;
}
else if (NIL_THD_IS_SUSP(tp)) {
*tp->u1.trp = NULL;
}
/*lint -restore*/
(void) chSchReadyI(tp, MSG_TIMEOUT);
}
else {
if (tp->timeout <= (systime_t)(next - (systime_t)1)) {
next = tp->timeout;
}
}
}
/* Lock released in order to give a preemption chance on those
architectures supporting IRQ preemption.*/
chSysUnlockFromISR();
tp++;
chSysLockFromISR();
} while (tp < &nil.threads[NIL_CFG_NUM_THREADS]);
nil.lasttime = nil.nexttime;
if (next > (systime_t)0) {
nil.nexttime += next;
port_timer_set_alarm(nil.nexttime);
}
else {
/* No tick event needed.*/
port_timer_stop_alarm();
}
#endif
}
/**
* @brief Unconditionally enters the kernel lock state.
* @note Can be called without previous knowledge of the current lock state.
* The final state is "s-locked".
*
* @special
*/
void chSysUnconditionalLock(void) {
if (port_irq_enabled(port_get_irq_status())) {
chSysLock();
}
}
/**
* @brief Unconditionally leaves the kernel lock state.
* @note Can be called without previous knowledge of the current lock state.
* The final state is "normal".
*
* @special
*/
void chSysUnconditionalUnlock(void) {
if (!port_irq_enabled(port_get_irq_status())) {
chSysUnlock();
}
}
/**
* @brief Returns the execution status and enters a critical zone.
* @details This functions enters into a critical zone and can be called
* from any context. Because its flexibility it is less efficient
* than @p chSysLock() which is preferable when the calling context
* is known.
* @post The system is in a critical zone.
*
* @return The previous system status, the encoding of this
* status word is architecture-dependent and opaque.
*
* @xclass
*/
syssts_t chSysGetStatusAndLockX(void) {
syssts_t sts = port_get_irq_status();
if (port_irq_enabled(sts)) {
if (port_is_isr_context()) {
chSysLockFromISR();
}
else {
chSysLock();
}
}
return sts;
}
/**
* @brief Restores the specified execution status and leaves a critical zone.
* @note A call to @p chSchRescheduleS() is automatically performed
* if exiting the critical zone and if not in ISR context.
*
* @param[in] sts the system status to be restored.
*
* @xclass
*/
void chSysRestoreStatusX(syssts_t sts) {
if (port_irq_enabled(sts)) {
if (port_is_isr_context()) {
chSysUnlockFromISR();
}
else {
chSchRescheduleS();
chSysUnlock();
}
}
}
/**
* @brief Makes the specified thread ready for execution.
*
* @param[in] tp pointer to the @p thread_t object
* @param[in] msg the wakeup message
*
* @return The same reference passed as parameter.
*/
thread_t *chSchReadyI(thread_t *tp, msg_t msg) {
chDbgAssert((tp >= nil.threads) &&
(tp < &nil.threads[NIL_CFG_NUM_THREADS]),
"pointer out of range");
chDbgAssert(!NIL_THD_IS_READY(tp), "already ready");
chDbgAssert(nil.next <= nil.current, "priority ordering");
tp->u1.msg = msg;
tp->state = NIL_STATE_READY;
tp->timeout = (systime_t)0;
if (tp < nil.next) {
nil.next = tp;
}
return tp;
}
/**
* @brief Reschedules if needed.
*
* @sclass
*/
void chSchRescheduleS(void) {
if (chSchIsRescRequiredI()) {
thread_t *otp = nil.current;
nil.current = nil.next;
if (otp == &nil.threads[NIL_CFG_NUM_THREADS]) {
NIL_CFG_IDLE_LEAVE_HOOK();
}
port_switch(nil.next, otp);
}
}
/**
* @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 chSchGoSleepTimeoutS(tstate_t newstate, systime_t timeout) {
thread_t *ntp, *otp = nil.current;
chDbgAssert(otp != &nil.threads[NIL_CFG_NUM_THREADS],
"idle cannot sleep");
/* Storing the wait object for the current thread.*/
otp->state = newstate;
#if NIL_CFG_ST_TIMEDELTA > 0
if (timeout != TIME_INFINITE) {
systime_t abstime;
/* TIMEDELTA makes sure to have enough time to reprogram the timer
before the free-running timer counter reaches the selected timeout.*/
if (timeout < (systime_t)NIL_CFG_ST_TIMEDELTA) {
timeout = (systime_t)NIL_CFG_ST_TIMEDELTA;
}
/* Absolute time of the timeout event.*/
abstime = chVTGetSystemTimeX() + timeout;
if (nil.lasttime == nil.nexttime) {
/* Special case, first thread asking for a timeout.*/
port_timer_start_alarm(abstime);
nil.nexttime = abstime;
}
else {
/* Special case, there are already other threads with a timeout
activated, evaluating the order.*/
if (chVTIsTimeWithinX(abstime, nil.lasttime, nil.nexttime)) {
port_timer_set_alarm(abstime);
nil.nexttime = abstime;
}
}
/* Timeout settings.*/
otp->timeout = abstime - nil.lasttime;
}
#else
/* Timeout settings.*/
otp->timeout = timeout;
#endif
/* Scanning the whole threads array.*/
ntp = nil.threads;
while (true) {
/* Is this thread ready to execute?*/
if (NIL_THD_IS_READY(ntp)) {
nil.current = nil.next = ntp;
if (ntp == &nil.threads[NIL_CFG_NUM_THREADS]) {
NIL_CFG_IDLE_ENTER_HOOK();
}
port_switch(ntp, otp);
return nil.current->u1.msg;
}
/* Points to the next thread in lowering priority order.*/
ntp++;
chDbgAssert(ntp <= &nil.threads[NIL_CFG_NUM_THREADS],
"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 chThdSuspendTimeoutS(thread_reference_t *trp, systime_t timeout) {
chDbgAssert(*trp == NULL, "not NULL");
*trp = nil.current;
nil.current->u1.trp = trp;
return chSchGoSleepTimeoutS(NIL_STATE_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 chThdResumeI(thread_reference_t *trp, msg_t msg) {
if (*trp != NULL) {
thread_reference_t tr = *trp;
chDbgAssert(NIL_THD_IS_SUSP(tr), "not suspended");
*trp = NULL;
(void) chSchReadyI(tr, msg);
}
}
/**
* @brief Suspends the invoking thread for the specified time.
*
* @param[in] timeout the delay in system ticks
*
* @api
*/
void chThdSleep(systime_t timeout) {
chSysLock();
chThdSleepS(timeout);
chSysUnlock();
}
/**
* @brief Suspends the invoking thread until the system time arrives to the
* specified value.
*
* @param[in] abstime absolute system time
*
* @api
*/
void chThdSleepUntil(systime_t abstime) {
chSysLock();
chThdSleepUntilS(abstime);
chSysUnlock();
}
/**
* @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 chSemReset().
* @retval NIL_MSG_TMO if the semaphore has not been signaled or reset within
* the specified timeout.
*
* @api
*/
msg_t chSemWaitTimeout(semaphore_t *sp, systime_t timeout) {
msg_t msg;
chSysLock();
msg = chSemWaitTimeoutS(sp, timeout);
chSysUnlock();
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 chSemReset().
* @retval NIL_MSG_TMO if the semaphore has not been signaled or reset within
* the specified timeout.
*
* @sclass
*/
msg_t chSemWaitTimeoutS(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 <= (cnt_t)0) {
if (TIME_IMMEDIATE == timeout) {
return MSG_TIMEOUT;
}
sp->cnt = cnt - (cnt_t)1;
nil.current->u1.semp = sp;
return chSchGoSleepTimeoutS(NIL_STATE_WTSEM, timeout);
}
sp->cnt = cnt - (cnt_t)1;
return 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 chSemSignal(semaphore_t *sp) {
chSysLock();
chSemSignalI(sp);
chSchRescheduleS();
chSysUnlock();
}
/**
* @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 chSemSignalI(semaphore_t *sp) {
if (++sp->cnt <= (cnt_t)0) {
thread_reference_t tr = nil.threads;
while (true) {
/* Is this thread waiting on this semaphore?*/
if (tr->u1.semp == sp) {
chDbgAssert(NIL_THD_IS_WTSEM(tr), "not waiting");
(void) chSchReadyI(tr, MSG_OK);
return;
}
tr++;
chDbgAssert(tr < &nil.threads[NIL_CFG_NUM_THREADS],
"pointer out of range");
}
}
}
/**
* @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 chSemReset(semaphore_t *sp, cnt_t n) {
chSysLock();
chSemResetI(sp, n);
chSchRescheduleS();
chSysUnlock();
}
/**
* @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 chSemResetI(semaphore_t *sp, cnt_t n) {
thread_t *tp;
cnt_t cnt;
cnt = sp->cnt;
sp->cnt = n;
tp = nil.threads;
while (cnt < (cnt_t)0) {
/* Is this thread waiting on this semaphore?*/
if (tp->u1.semp == sp) {
chDbgAssert(NIL_THD_IS_WTSEM(tp), "not waiting");
cnt++;
(void) chSchReadyI(tp, MSG_RESET);
}
tp++;
chDbgAssert(tp < &nil.threads[NIL_CFG_NUM_THREADS],
"pointer out of range");
}
}
/**
* @brief Adds a set of event flags directly to the specified @p thread_t.
*
* @param[in] tp the thread to be signaled
* @param[in] mask the event flags set to be ORed
*
* @api
*/
void chEvtSignal(thread_t *tp, eventmask_t mask) {
chSysLock();
chEvtSignalI(tp, mask);
chSchRescheduleS();
chSysUnlock();
}
/**
* @brief Adds a set of event flags directly to the specified @p thread_t.
* @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] tp the thread to be signaled
* @param[in] mask the event flags set to be ORed
*
* @iclass
*/
void chEvtSignalI(thread_t *tp, eventmask_t mask) {
tp->epmask |= mask;
if (NIL_THD_IS_WTOREVT(tp) &&
((tp->epmask & tp->u1.ewmask) != (eventmask_t)0)) {
(void) chSchReadyI(tp, MSG_OK);
}
}
/**
* @brief Waits for any of the specified events.
* @details The function waits for any event among those specified in
* @p mask to become pending then the events are cleared and
* returned.
*
* @param[in] mask mask of the event flags that the function should wait
* for, @p ALL_EVENTS enables all the events
* @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 The mask of the served and cleared events.
* @retval 0 if the operation has timed out.
*
* @api
*/
eventmask_t chEvtWaitAnyTimeout(eventmask_t mask, systime_t timeout) {
eventmask_t m;
chSysLock();
m = chEvtWaitAnyTimeoutS(mask, timeout);
chSysUnlock();
return m;
}
/**
* @brief Waits for any of the specified events.
* @details The function waits for any event among those specified in
* @p mask to become pending then the events are cleared and
* returned.
*
* @param[in] mask mask of the event flags that the function should wait
* for, @p ALL_EVENTS enables all the events
* @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 The mask of the served and cleared events.
* @retval 0 if the operation has timed out.
*
* @sclass
*/
eventmask_t chEvtWaitAnyTimeoutS(eventmask_t mask, systime_t timeout) {
thread_t *ctp = nil.current;
eventmask_t m;
if ((m = (ctp->epmask & mask)) == (eventmask_t)0) {
if (TIME_IMMEDIATE == timeout) {
chSysUnlock();
return (eventmask_t)0;
}
ctp->u1.ewmask = mask;
if (chSchGoSleepTimeoutS(NIL_STATE_WTOREVT, timeout) < MSG_OK) {
chSysUnlock();
return (eventmask_t)0;
}
m = ctp->epmask & mask;
}
ctp->epmask &= ~m;
return m;
}
/** @} */